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Sample records for affects proteasome interacting

  1. Effects of ethanol on the proteasome interacting proteins

    Institute of Scientific and Technical Information of China (English)

    Fawzia; Bardag-Gorce

    2010-01-01

    Proteasome dysfunction has been repeatedly reported in alcoholic liver disease. Ethanol metabolism endproducts affect the structure of the proteasome, and, therefore, change the proteasome interaction with its regulatory complexes 19S and PA28, as well as its interacting proteins. Chronic ethanol feeding alters the ubiquitin-proteasome activity by altering the interaction between the 19S and the 20S proteasome interaction. The degradation of oxidized and damaged proteins is thus decreased and leads to accum...

  2. Proteins interacting with the 26S proteasome

    DEFF Research Database (Denmark)

    Hartmann-Petersen, R; Gordon, C

    2004-01-01

    The 26S proteasome is the multi-protein protease that recognizes and degrades ubiquitinylated substrates targeted for destruction by the ubiquitin pathway. In addition to the well-documented subunit organization of the 26S holoenzyme, it is clear that a number of other proteins transiently...... associate with the 26S complex. These transiently associated proteins confer a number of different roles such as substrate presentation, cleavage of the multi-ubiquitin chain from the protein substrate and turnover of misfolded proteins. Such activities are essential for the 26S proteasome to efficiently...... fulfill its intracellular function in protein degradation....

  3. Integral UBL domain proteins: a family of proteasome interacting proteins

    DEFF Research Database (Denmark)

    Hartmann-Petersen, Rasmus; Gordon, Colin

    2004-01-01

    The family of ubiquitin-like (UBL) domain proteins (UDPs) comprises a conserved group of proteins involved in a multitude of different cellular activities. However, recent studies on UBL-domain proteins indicate that these proteins appear to share a common property in their ability to interact with......-domain proteins catalyse the formation of ubiquitin-protein conjugates, whereas others appear to target ubiquitinated proteins for degradation and interact with chaperones. Hence, by binding to the 26S proteasome the UBL-domain proteins seem to tailor and direct the basic proteolytic functions of the particle to...... 26S proteasomes. The 26S proteasome is a multisubunit protease which is responsible for the majority of intracellular proteolysis in eukaryotic cells. Before degradation commences most proteins are first marked for destruction by being coupled to a chain of ubiquitin molecules. Some UBL...

  4. Plasminogen activator inhibitor type 1 interacts with alpha3 subunit of proteasome and modulates its activity.

    Science.gov (United States)

    Boncela, Joanna; Przygodzka, Patrycja; Papiewska-Pajak, Izabela; Wyroba, Elzbieta; Osinska, Magdalena; Cierniewski, Czeslaw S

    2011-02-25

    Plasminogen activator inhibitor type-1 (PAI-1), a multifunctional protein, is an important physiological regulator of fibrinolysis, extracellular matrix homeostasis, and cell motility. Recent observations show that PAI-1 may also be implicated in maintaining integrity of cells, especially with respect to cellular proliferation or apoptosis. In the present study we provide evidence that PAI-1 interacts with proteasome and affects its activity. First, by using the yeast two-hybrid system, we found that the α3 subunit of proteasome directly interacts with PAI-1. Then, to ensure that the PAI-1-proteasome complex is formed in vivo, both proteins were coimmunoprecipitated from endothelial cells and identified with specific antibodies. The specificity of this interaction was evidenced after transfection of HeLa cells with pCMV-PAI-1 and coimmunoprecipitation of both proteins with anti-PAI-1 antibodies. Subsequently, cellular distribution of the PAI-1-proteasome complexes was established by immunogold staining and electron microscopy analyses. Both proteins appeared in a diffuse cytosolic pattern but also could be found in a dense perinuclear and nuclear location. Furthermore, PAI-1 induced formation of aggresomes freely located in endothelial cytoplasm. Increased PAI-1 expression abrogated degradation of degron analyzed after cotransfection of HeLa cells with pCMV-PAI-1 and pd2EGFP-N1 and prevented degradation of p53 as well as IκBα, as evidenced both by confocal microscopy and Western immunoblotting.

  5. Plasminogen Activator Inhibitor Type 1 Interacts with α3 Subunit of Proteasome and Modulates Its Activity*

    Science.gov (United States)

    Boncela, Joanna; Przygodzka, Patrycja; Papiewska-Pajak, Izabela; Wyroba, Elzbieta; Osinska, Magdalena; Cierniewski, Czeslaw S.

    2011-01-01

    Plasminogen activator inhibitor type-1 (PAI-1), a multifunctional protein, is an important physiological regulator of fibrinolysis, extracellular matrix homeostasis, and cell motility. Recent observations show that PAI-1 may also be implicated in maintaining integrity of cells, especially with respect to cellular proliferation or apoptosis. In the present study we provide evidence that PAI-1 interacts with proteasome and affects its activity. First, by using the yeast two-hybrid system, we found that the α3 subunit of proteasome directly interacts with PAI-1. Then, to ensure that the PAI-1-proteasome complex is formed in vivo, both proteins were coimmunoprecipitated from endothelial cells and identified with specific antibodies. The specificity of this interaction was evidenced after transfection of HeLa cells with pCMV-PAI-1 and coimmunoprecipitation of both proteins with anti-PAI-1 antibodies. Subsequently, cellular distribution of the PAI-1-proteasome complexes was established by immunogold staining and electron microscopy analyses. Both proteins appeared in a diffuse cytosolic pattern but also could be found in a dense perinuclear and nuclear location. Furthermore, PAI-1 induced formation of aggresomes freely located in endothelial cytoplasm. Increased PAI-1 expression abrogated degradation of degron analyzed after cotransfection of HeLa cells with pCMV-PAI-1 and pd2EGFP-N1 and prevented degradation of p53 as well as IκBα, as evidenced both by confocal microscopy and Western immunoblotting. PMID:21135093

  6. Inhibition of Nek2 by Small Molecules Affects Proteasome Activity

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    Lingyao Meng

    2014-01-01

    Full Text Available Background. Nek2 is a serine/threonine kinase localized to the centrosome. It promotes cell cycle progression from G2 to M by inducing centrosome separation. Recent studies have shown that high Nek2 expression is correlated with drug resistance in multiple myeloma patients. Materials and Methods. To investigate the role of Nek2 in bortezomib resistance, we ectopically overexpressed Nek2 in several cancer cell lines, including multiple myeloma lines. Small-molecule inhibitors of Nek2 were discovered using an in-house library of compounds. We tested the inhibitors on proteasome and cell cycle activity in several cell lines. Results. Proteasome activity was elevated in Nek2-overexpressing cell lines. The Nek2 inhibitors inhibited proteasome activity in these cancer cell lines. Treatment with these inhibitors resulted in inhibition of proteasome-mediated degradation of several cell cycle regulators in HeLa cells, leaving them arrested in G2/M. Combining these Nek2 inhibitors with bortezomib increased the efficacy of bortezomib in decreasing proteasome activity in vitro. Treatment with these novel Nek2 inhibitors successfully mitigated drug resistance in bortezomib-resistant multiple myeloma. Conclusion. Nek2 plays a central role in proteasome-mediated cell cycle regulation and in conferring resistance to bortezomib in cancer cells. Taken together, our results introduce Nek2 as a therapeutic target in bortezomib-resistant multiple myeloma.

  7. Proteasome Activity Is Affected by Fluctuations in Insulin-Degrading Enzyme Distribution.

    Science.gov (United States)

    Sbardella, Diego; Tundo, Grazia Raffaella; Sciandra, Francesca; Bozzi, Manuela; Gioia, Magda; Ciaccio, Chiara; Tarantino, Umberto; Brancaccio, Andrea; Coletta, Massimo; Marini, Stefano

    2015-01-01

    Insulin-Degrading-Enzyme (IDE) is a Zn2+-dependent peptidase highly conserved throughout evolution and ubiquitously distributed in mammalian tissues wherein it displays a prevalent cytosolic localization. We have recently demonstrated a novel Heat Shock Protein-like behaviour of IDE and its association with the 26S proteasome. In the present study, we examine the mechanistic and molecular features of IDE-26S proteasome interaction in a cell experimental model, extending the investigation also to the effect of IDE on the enzymatic activities of the 26S proteasome. Further, kinetic investigations indicate that the 26S proteasome activity undergoes a functional modulation by IDE through an extra-catalytic mechanism. The IDE-26S proteasome interaction was analyzed during the Heat Shock Response and we report novel findings on IDE intracellular distribution that might be of critical relevance for cell metabolism.

  8. Proteasome Activity Is Affected by Fluctuations in Insulin-Degrading Enzyme Distribution.

    Directory of Open Access Journals (Sweden)

    Diego Sbardella

    Full Text Available Insulin-Degrading-Enzyme (IDE is a Zn2+-dependent peptidase highly conserved throughout evolution and ubiquitously distributed in mammalian tissues wherein it displays a prevalent cytosolic localization. We have recently demonstrated a novel Heat Shock Protein-like behaviour of IDE and its association with the 26S proteasome. In the present study, we examine the mechanistic and molecular features of IDE-26S proteasome interaction in a cell experimental model, extending the investigation also to the effect of IDE on the enzymatic activities of the 26S proteasome. Further, kinetic investigations indicate that the 26S proteasome activity undergoes a functional modulation by IDE through an extra-catalytic mechanism. The IDE-26S proteasome interaction was analyzed during the Heat Shock Response and we report novel findings on IDE intracellular distribution that might be of critical relevance for cell metabolism.

  9. Structural Models for Interactions between the 20S Proteasome and Its PAN/19S Activators

    Energy Technology Data Exchange (ETDEWEB)

    Stadtmueller, B.; Ferrell, K; Whitby, F; Heroux, A; Robinson, H; Myszka, D; Hill, C

    2009-01-01

    Proteasome activity is regulated by sequestration of its proteolytic centers in a barrel-shaped structure that limits substrate access. Substrates enter the proteasome by means of activator complexes that bind to the end rings of proteasome alpha subunits and induce opening of an axial entrance/exit pore. The PA26 activator binds in a pocket on the proteasome surface using main chain contacts of its C-terminal residues and uses an internal activation loop to trigger gate opening by repositioning the proteasome Pro-17 reverse turn. Subunits of the unrelated PAN/19S activators bind with their C termini in the same pockets but can induce proteasome gate opening entirely from interactions of their C-terminal peptides, which are reported to cause gate opening by inducing a rocking motion of proteasome alpha subunits rather than by directly contacting the Pro-17 turn. Here we report crystal structures and binding studies of proteasome complexes with PA26 constructs that display modified C-terminal residues, including those corresponding to PAN. These findings suggest that PA26 and PAN/19S C-terminal residues bind superimposably and that both classes of activator induce gate opening by using direct contacts to residues of the proteasome Pro-17 reverse turn. In the case of the PAN and 19S activators, a penultimate tyrosine/phenylalanine residue contacts the proteasome Gly-19 carbonyl oxygen to stabilize the open conformation.

  10. Bacterial proteasome and PafA, the pup ligase, interact to form a modular protein tagging and degradation machine.

    Science.gov (United States)

    Forer, Nadav; Korman, Maayan; Elharar, Yifat; Vishkautzan, Marina; Gur, Eyal

    2013-12-17

    Proteasome-containing bacteria possess a tagging system that directs proteins to proteasomal degradation by conjugating them to a prokaryotic ubiquitin-like protein (Pup). A single ligating enzyme, PafA, is responsible for Pup conjugation to lysine side chains of protein substrates. As Pup is recognized by the regulatory subunit of the proteasome, Pup functions as a degradation tag. Pup presents overlapping regions for binding of the proteasome and PafA. It was, therefore, unclear whether Pup binding by the proteasome regulatory subunit, Mpa, and by PafA are mutually exclusive events. The work presented here provides evidence for the simultaneous interaction of Pup with both Mpa and PafA. Surprisingly, we found that PafA and Mpa can form a complex both in vitro and in vivo. Our results thus suggest that PafA and the proteasome can function as a modular machine for the tagging and degradation of cytoplasmic proteins. PMID:24228735

  11. Experiencing affective interactive art

    NARCIS (Netherlands)

    Bialoskorski, Leticia S.S.; Westerink, Joyce H.D.M.; Broek, van den Egon L.

    2010-01-01

    The progress in the field of affective computing enables the realization of affective art. This paper describes the affective interactive art system Mood Swings, which interprets and visualizes affect expressed by a person. Mood Swings is founded on the integration of a framework for affective move

  12. Interaction between misfolded PrP and the ubiquitin-proteasome system in prion-mediated neurodegeneration

    Institute of Scientific and Technical Information of China (English)

    Zhu Lin; Deming Zhao; Lifeng Yang

    2013-01-01

    Prion diseases are associated with the conformational conversion of cellular prion protein (PrPC) to pathological β-sheet isoforms (PrpSc),which is the infectious agent beyond comprehension.Increasing evidence indicated that an unknown toxic gain of function of PrPSc underlies neuronal death.Conversely,strong evidence indicated that cellular prion protein might be directly cytotoxic by mediating neurotoxic signaling of β-sheet-rich conformers independent of prion replication.Furthermore,the common properties of β-sheet-rich isoform such as PrPSc and β amyloid protein become the lynchpin that interprets the general pathological mechanism of protein misfolding diseases.Dysfunction of the ubiquitin-proteasome system (UPS) has been implicated in various protein misfolding diseases.However,the mechanisms of this impairment remain unknown in many cases.In prion disease,prioninfected mouse brains have increased levels of ubiquitin conjugates,which correlate with decreased proteasome function.Both PrPC and PrPsc accumulate in cells after proteasome inhibition,which leads to increased cell death.A direct interaction between 20S core particle and PrP isoforms was demonstrated.Here we review the ability of misfolded PrP and UPS to affect each other,which might contribute to the pathological features of prion-mediated neurodegeneration.

  13. Gel-based chemical cross-linking analysis of 20S proteasome subunit-subunit interactions in breast cancer.

    Science.gov (United States)

    Song, Hai; Xiong, Hua; Che, Jing; Xi, Qing-Song; Huang, Liu; Xiong, Hui-Hua; Zhang, Peng

    2016-08-01

    The ubiquitin-proteasome system plays a pivotal role in breast tumorigenesis by controlling transcription factors, thus promoting cell cycle growth, and degradation of tumor suppressor proteins. However, breast cancer patients have failed to benefit from proteasome inhibitor treatment partially due to proteasome heterogeneity, which is poorly understood in malignant breast neoplasm. Chemical crosslinking is an increasingly important tool for mapping protein three-dimensional structures and proteinprotein interactions. In the present study, two cross-linkers, bis (sulfosuccinimidyl) suberate (BS(3)) and its water-insoluble analog disuccinimidyl suberate (DSS), were used to map the subunit-subunit interactions in 20S proteasome core particle (CP) from MDA-MB-231 cells. Different types of gel electrophoresis technologies were used. In combination with chemical cross-linking and mass spectrometry, we applied these gel electrophoresis technologies to the study of the noncovalent interactions among 20S proteasome subunits. Firstly, the CP subunit isoforms were profiled. Subsequently, using native/SDSPAGE, it was observed that 0.5 mmol/L BS(3) was a relatively optimal cross-linking concentration for CP subunit-subunit interaction study. 2-DE analysis of the cross-linked CP revealed that α1 might preinteract with α2, and α3 might pre-interact with α4. Moreover, there were different subtypes of α1α2 and α3α4 due to proteasome heterogeneity. There was no significant difference in cross-linking pattern for CP subunits between BS(3) and DSS. Taken together, the gel-based characterization in combination with chemical cross-linking could serve as a tool for the study of subunit interactions within a multi-subunit protein complex. The heterogeneity of 20S proteasome subunit observed in breast cancer cells may provide some key information for proteasome inhibition strategy. PMID:27465334

  14. Proteasome β5i Subunit Deficiency Affects Opsonin Synthesis and Aggravates Pneumococcal Pneumonia.

    Science.gov (United States)

    Kirschner, Felicia; Reppe, Katrin; Andresen, Nadine; Witzenrath, Martin; Ebstein, Frédéric; Kloetzel, Peter-Michael

    2016-01-01

    Immunoproteasomes, harboring the active site subunits β5i/LMP7, β1i/LMP2, and β2i/MECL1 exert protective, regulatory or modulating functions during infection-induced immune responses. Immunoproteasomes are constitutively expressed in hematopoietic derived cells, constituting the first line of defense against invading pathogens. To clarify the impact of immunoproteasomes on the innate immune response against Streptococcus pneumoniae, we characterized the progression of disease and analyzed the systemic immune response in β5i/LMP7-/- mice. Our data show that β5i/LMP7 deficiency, which affected the subunit composition of proteasomes in murine macrophages and liver, was accompanied by reduced transcription of genes encoding immune modulating molecules such as pentraxins, ficolins, and collectins. The diminished opsonin expression suggested an impaired humoral immune response against invading pneumococci resulting in an aggravated systemic dissemination of S. pneumoniae in β5i/LMP7-/- mice. The impaired bacterial elimination in β5i/LMP7-/- mice was accompanied by an aggravated course of pneumonia with early mortality as a consequence of critical illness during the late phase of disease. In summary our results highlight an unsuspected role for immuno-subunits in modulating the innate immune response to extracellular bacterial infections. PMID:27100179

  15. HIV-1 replication through hHR23A-mediated interaction of Vpr with 26S proteasome.

    Directory of Open Access Journals (Sweden)

    Ge Li

    Full Text Available HIV-1 Vpr is a virion-associated protein. Its activities link to viral pathogenesis and disease progression of HIV-infected patients. In vitro, Vpr moderately activates HIV-1 replication in proliferating T cells, but it is required for efficient viral infection and replication in vivo in non-dividing cells such as macrophages. How exactly Vpr contributes to viral replication remains elusive. We show here that Vpr stimulates HIV-1 replication at least in part through its interaction with hHR23A, a protein that binds to 19S subunit of the 26S proteasome and shuttles ubiquitinated proteins to the proteasome for degradation. The Vpr-proteasome interaction was initially discovered in fission yeast, where Vpr was shown to associate with Mts4 and Mts2, two 19S-associated proteins. The interaction of Vpr with the 19S subunit of the proteasome was further confirmed in mammalian cells where Vpr associates with the mammalian orthologues of fission yeast Mts4 and S5a. Consistently, depletion of hHR23A interrupts interaction of Vpr with proteasome in mammalian cells. Furthermore, Vpr promotes hHR23A-mediated protein-ubiquitination, and down-regulation of hHR23A using RNAi significantly reduced viral replication in non-proliferating MAGI-CCR5 cells and primary macrophages. These findings suggest that Vpr-proteasome interaction might counteract certain host restriction factor(s to stimulate viral replication in non-dividing cells.

  16. Interaction of Plasminogen Activator Inhibitor-2 and Proteasome Subunit, Beta Type 1

    Institute of Scientific and Technical Information of China (English)

    JingFAN; Yu-QingZHANG; PingLI; MinHOU; LiTAN; XiaWANG; Yun-SongZHU

    2004-01-01

    The apoptosis protection by plasminogen activator inhibitor-2(PAI-2) is dependent on a 33 amino acid fragment between helix C and D of PAI-2 which is probably due to the interaction of PAI-2 with unknown intracellular proteins. In this study, we used the fragment between helix C and D of PAI-2 as bait to screen a HeLa cell cDNA library constructed during apoptosis in a yeast two-hybrid system and retrieved a clone encoding 241 amino acids of proteasome (prosome, macropain) subunit, beta type 1(PSMβ1) which plays important roles in NF-κB activation. GST-pulldown experiments confirmed the interaction between PAI-2 and PSMβ1 in vitro. These data suggest that the antiapoptosis activity of PAI-2 is probably related to its interation with PSMβ1.

  17. Interactive effects of CO₂ and trace metals on the proteasome activity and cellular stress response of marine bivalves Crassostrea virginica and Mercenaria mercenaria

    Energy Technology Data Exchange (ETDEWEB)

    Götze, Sandra [Alfred Wegener Institute, Helmholtz Centre for Polar, Marine Research, Functional Ecology, 27570 Bremerhaven (Germany); Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Matoo, Omera B. [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Beniash, Elia [Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA (United States); Saborowski, Reinhard [Alfred Wegener Institute, Helmholtz Centre for Polar, Marine Research, Functional Ecology, 27570 Bremerhaven (Germany); Sokolova, Inna M., E-mail: isokolov@uncc.edu [Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223 (United States)

    2014-04-01

    Highlights: • Elevated PCO₂ enhanced accumulation of Cu and Cd in the gills of mollusks. • The proteasome activities were affected by metals but robust to elevated PCO₂. • Exposure to Cd and Cu had opposite effects on the proteasome activity. • Combined exposure to Cu and elevated PCO₂ negatively affected energy status. - Abstract: Increased anthropogenic emission of CO₂ changes the carbonate chemistry and decreases the pH of the ocean. This can affect the speciation and the bioavailability of metals in polluted habitats such as estuaries. However, the effects of acidification on metal accumulation and stress response in estuarine organisms including bivalves are poorly understood. We studied the interactive effects of CO₂ and two common metal pollutants, copper (Cu) and cadmium (Cd), on metal accumulation, intracellular ATP/ubiquitin-dependent protein degradation, stress response and energy metabolism in two common estuarine bivalves—Crassostrea virginica (eastern oyster) and Mercenaria mercenaria (hard shell clam). Bivalves were exposed for 4–5 weeks to clean seawater (control) and to either 50 μg L⁻¹ Cu or 50 μg L⁻¹ Cd at one of three partial pressures of CO₂ PCO₂ ~395, ~800 and ~1500 μatm) representative of the present-day conditions and projections of the Intergovernmental Panel for Climate Change (IPCC) for the years 2100 and 2250, respectively. Clams accumulated lower metal burdens than oysters, and elevated PCO₂ enhanced the Cd and Cu accumulation in mantle tissues in both species. Higher Cd and Cu burdens were associated with elevated mRNA expression of metal binding proteins metallothionein and ferritin. In the absence of added metals, proteasome activities of clams and oysters were robust to elevated PCO₂, but PCO₂ modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome

  18. Plastidial starch phosphorylase in sweet potato roots is proteolytically modified by protein-protein interaction with the 20S proteasome.

    Directory of Open Access Journals (Sweden)

    Yi-Chen Lin

    Full Text Available Post-translational regulation plays an important role in cellular metabolism. Earlier studies showed that the activity of plastidial starch phosphorylase (Pho1 may be regulated by proteolytic modification. During the purification of Pho1 from sweet potato roots, we observed an unknown high molecular weight complex (HX showing Pho1 activity. The two-dimensional gel electrophoresis, mass spectrometry, and reverse immunoprecipitation analyses showed that HX is composed of Pho1 and the 20S proteasome. Incubating sweet potato roots at 45°C triggers a stepwise degradation of Pho1; however, the degradation process can be partially inhibited by specific proteasome inhibitor MG132. The proteolytically modified Pho1 displays a lower binding affinity toward glucose 1-phosphate and a reduced starch-synthesizing activity. This study suggests that the 20S proteasome interacts with Pho1 and is involved in the regulation of the catalytic activity of Pho1 in sweet potato roots under heat stress conditions.

  19. Urban Interaction and Affective Experience

    DEFF Research Database (Denmark)

    Fritsch, Jonas; Brynskov, Martin

    2008-01-01

    in favor of three points in that direction: First we argue that interaction – and the definition of interaction – is central to unfold the potential of digital urban media, from big, shared screens and media facades to small pri-vate, networked mobile and embedded platforms. Then we argue that an affective...

  20. Affective Computing and Intelligent Interaction

    CERN Document Server

    2012-01-01

    2012 International Conference on Affective Computing and Intelligent Interaction (ICACII 2012) was the most comprehensive conference focused on the various aspects of advances in Affective Computing and Intelligent Interaction. The conference provided a rare opportunity to bring together worldwide academic researchers and practitioners for exchanging the latest developments and applications in this field such as Intelligent Computing, Affective Computing, Machine Learning, Business Intelligence and HCI.   This volume is a collection of 119 papers selected from 410 submissions from universities and industries all over the world, based on their quality and relevancy to the conference. All of the papers have been peer-reviewed by selected experts.  

  1. Interactive effects of CO₂ and trace metals on the proteasome activity and cellular stress response of marine bivalves Crassostrea virginica and Mercenaria mercenaria.

    Science.gov (United States)

    Götze, Sandra; Matoo, Omera B; Beniash, Elia; Saborowski, Reinhard; Sokolova, Inna M

    2014-04-01

    Increased anthropogenic emission of CO2 changes the carbonate chemistry and decreases the pH of the ocean. This can affect the speciation and the bioavailability of metals in polluted habitats such as estuaries. However, the effects of acidification on metal accumulation and stress response in estuarine organisms including bivalves are poorly understood. We studied the interactive effects of CO2 and two common metal pollutants, copper (Cu) and cadmium (Cd), on metal accumulation, intracellular ATP/ubiquitin-dependent protein degradation, stress response and energy metabolism in two common estuarine bivalves-Crassostrea virginica (eastern oyster) and Mercenaria mercenaria (hard shell clam). Bivalves were exposed for 4-5 weeks to clean seawater (control) and to either 50 μg L(-1) Cu or 50 μg L(-1) Cd at one of three partial pressures of CO2 ( [Formula: see text] ∼ 395, ∼ 800 and ∼ 1500 μatm) representative of the present-day conditions and projections of the Intergovernmental Panel for Climate Change (IPCC) for the years 2100 and 2250, respectively. Clams accumulated lower metal burdens than oysters, and elevated [Formula: see text] enhanced the Cd and Cu accumulation in mantle tissues in both species. Higher Cd and Cu burdens were associated with elevated mRNA expression of metal binding proteins metallothionein and ferritin. In the absence of added metals, proteasome activities of clams and oysters were robust to elevated [Formula: see text] , but [Formula: see text] modulated the proteasome response to metals. Cd exposure stimulated the chymotrypsin-like activity of the oyster proteasome at all CO2 levels. In contrast, trypsin- and caspase-like activities of the oyster proteasome were slightly inhibited by Cd exposure in normocapnia but this inhibition was reversed at elevated [Formula: see text] . Cu exposure inhibited the chymotrypsin-like activity of the oyster proteasome regardless of the exposure [Formula: see text] . The effects of metal exposure on

  2. Protein Interaction between Ameloblastin and Proteasome Subunit α Type 3 Can Facilitate Redistribution of Ameloblastin Domains within Forming Enamel.

    Science.gov (United States)

    Geng, Shuhui; White, Shane N; Paine, Michael L; Snead, Malcolm L

    2015-08-21

    Enamel is a bioceramic tissue composed of thousands of hydroxyapatite crystallites aligned in parallel within boundaries fabricated by a single ameloblast cell. Enamel is the hardest tissue in the vertebrate body; however, it starts development as a self-organizing assembly of matrix proteins that control crystallite habit. Here, we examine ameloblastin, a protein that is initially distributed uniformly across the cell boundary but redistributes to the lateral margins of the extracellular matrix following secretion thus producing cell-defined boundaries within the matrix and the mineral phase. The yeast two-hybrid assay identified that proteasome subunit α type 3 (Psma3) interacts with ameloblastin. Confocal microscopy confirmed Psma3 co-distribution with ameloblastin at the ameloblast secretory end piece. Co-immunoprecipitation assay of mouse ameloblast cell lysates with either ameloblastin or Psma3 antibody identified each reciprocal protein partner. Protein engineering demonstrated that only the ameloblastin C terminus interacts with Psma3. We show that 20S proteasome digestion of ameloblastin in vitro generates an N-terminal cleavage fragment consistent with the in vivo pattern of ameloblastin distribution. These findings suggest a novel pathway participating in control of protein distribution within the extracellular space that serves to regulate the protein-mineral interactions essential to biomineralization.

  3. Discovery of novel interacting partners of PSMD9, a proteasomal chaperone: Role of an Atypical and versatile PDZ-domain motif interaction and identification of putative functional modules

    Science.gov (United States)

    Sangith, Nikhil; Srinivasaraghavan, Kannan; Sahu, Indrajit; Desai, Ankita; Medipally, Spandana; Somavarappu, Arun Kumar; Verma, Chandra; Venkatraman, Prasanna

    2014-01-01

    PSMD9 (Proteasome Macropain non-ATPase subunit 9), a proteasomal assembly chaperone, harbors an uncharacterized PDZ-like domain. Here we report the identification of five novel interacting partners of PSMD9 and provide the first glimpse at the structure of the PDZ-domain, including the molecular details of the interaction. We based our strategy on two propositions: (a) proteins with conserved C-termini may share common functions and (b) PDZ domains interact with C-terminal residues of proteins. Screening of C-terminal peptides followed by interactions using full-length recombinant proteins, we discovered hnRNPA1 (an RNA binding protein), S14 (a ribosomal protein), CSH1 (a growth hormone), E12 (a transcription factor) and IL6 receptor as novel PSMD9-interacting partners. Through multiple techniques and structural insights, we clearly demonstrate for the first time that human PDZ domain interacts with the predicted Short Linear Sequence Motif (SLIM) at the C-termini of the client proteins. These interactions are also recapitulated in mammalian cells. Together, these results are suggestive of the role of PSMD9 in transcriptional regulation, mRNA processing and editing, hormone and receptor activity and protein translation. Our proof-of-principle experiments endorse a novel and quick method for the identification of putative interacting partners of similar PDZ-domain proteins from the proteome and for discovering novel functions. PMID:25009770

  4. Discovery of novel interacting partners of PSMD9, a proteasomal chaperone: Role of an Atypical and versatile PDZ-domain motif interaction and identification of putative functional modules

    Directory of Open Access Journals (Sweden)

    Nikhil Sangith

    2014-01-01

    Full Text Available PSMD9 (Proteasome Macropain non-ATPase subunit 9, a proteasomal assembly chaperone, harbors an uncharacterized PDZ-like domain. Here we report the identification of five novel interacting partners of PSMD9 and provide the first glimpse at the structure of the PDZ-domain, including the molecular details of the interaction. We based our strategy on two propositions: (a proteins with conserved C-termini may share common functions and (b PDZ domains interact with C-terminal residues of proteins. Screening of C-terminal peptides followed by interactions using full-length recombinant proteins, we discovered hnRNPA1 (an RNA binding protein, S14 (a ribosomal protein, CSH1 (a growth hormone, E12 (a transcription factor and IL6 receptor as novel PSMD9-interacting partners. Through multiple techniques and structural insights, we clearly demonstrate for the first time that human PDZ domain interacts with the predicted Short Linear Sequence Motif (SLIM at the C-termini of the client proteins. These interactions are also recapitulated in mammalian cells. Together, these results are suggestive of the role of PSMD9 in transcriptional regulation, mRNA processing and editing, hormone and receptor activity and protein translation. Our proof-of-principle experiments endorse a novel and quick method for the identification of putative interacting partners of similar PDZ-domain proteins from the proteome and for discovering novel functions.

  5. Characterisation of the Trichinella spiralis deubiquitinating enzyme, TsUCH37, an evolutionarily conserved proteasome interaction partner.

    Directory of Open Access Journals (Sweden)

    Rhiannon R White

    2011-10-01

    Full Text Available BACKGROUND: Trichinella spiralis is a zoonotic parasitic nematode that causes trichinellosis, a disease that has been identified on all continents except Antarctica. During chronic infection, T. spiralis larvae infect skeletal myofibres, severely disrupting their differentiation state. METHODOLOGY AND RESULTS: An activity-based probe, HA-Ub-VME, was used to identify deubiquitinating enzyme (DUB activity in lysate of T. spiralis L1 larvae. Results were analysed by immuno-blot and immuno-precipitation, identifying a number of potential DUBs. Immuno-precipitated proteins were subjected to LC/MS/MS, yielding peptides with sequence homology to 5 conserved human DUBs: UCH-L5, UCH-L3, HAUSP, OTU 6B and Ataxin-3. The predicted gene encoding the putative UCH-L5 homologue, TsUCH37, was cloned and recombinant protein was expressed and purified. The deubiquitinating activity of this enzyme was verified by Ub-AMC assay. Co-precipitation of recombinant TsUCH37 showed that the protein associates with putative T. spiralis proteasome components, including the yeast Rpn13 homologue ADRM1. In addition, the UCH inhibitor LDN-57444 exhibited specific inhibition of recombinant TsUCH37 and reduced the viability of cultured L1 larvae. CONCLUSIONS: This study reports the identification of the first T. spiralis DUB, a cysteine protease that is putatively orthologous to the human protein, hUCH-L5. Results suggest that the interaction of this protein with the proteasome has been conserved throughout evolution. We show potential for the use of inhibitor compounds to elucidate the role of UCH enzymes in T. spiralis infection and their investigation as therapeutic targets for trichinellosis.

  6. The T210M Substitution in the HLA-a*02:01 gp100 Epitope Strongly Affects Overall Proteasomal Cleavage Site Usage and Antigen Processing.

    Science.gov (United States)

    Textoris-Taube, Kathrin; Keller, Christin; Liepe, Juliane; Henklein, Petra; Sidney, John; Sette, Alessandro; Kloetzel, Peter M; Mishto, Michele

    2015-12-18

    MHC class I-restricted epitopes, which carry a tumor-specific mutation resulting in improved MHC binding affinity, are preferred T cell receptor targets in innovative adoptive T cell therapies. However, T cell therapy requires efficient generation of the selected epitope. How such mutations may affect proteasome-mediated antigen processing has so far not been studied. Therefore, we analyzed by in vitro experiments the effect on antigen processing and recognition of a T210M exchange, which previously had been introduced into the melanoma gp100209-217 tumor epitope to improve the HLA-A*02:01 binding and its immunogenicity. A quantitative analysis of the main steps of antigen processing shows that the T210M exchange affects proteasomal cleavage site usage within the mutgp100201-230 polypeptide, leading to the generation of an unique set of cleavage products. The T210M substitution qualitatively affects the proteasome-catalyzed generation of spliced and non-spliced peptides predicted to bind HLA-A or -B complexes. The T210M substitution also induces an enhanced production of the mutgp100209-217 epitope and its N-terminally extended peptides. The T210M exchange revealed no effect on ERAP1-mediated N-terminal trimming of the precursor peptides. However, mutant N-terminally extended peptides exhibited significantly increased HLA-A*02:01 binding affinity and elicited CD8(+) T cell stimulation in vitro similar to the wtgp100209-217 epitope. Thus, our experiments demonstrate that amino acid exchanges within an epitope can result in the generation of an altered peptide pool with new antigenic peptides and in a wider CD8(+) T cell response also towards N-terminally extended versions of the minimal epitope. PMID:26507656

  7. Come, see and experience affective interactive art

    NARCIS (Netherlands)

    Bialoskorski, Leticia S.S.; Westerink, Joyce H.D.M.; Broek, van den Egon L.; Nijholt, Anton; Reidsma, Dennis; Hondorp, Hendri

    2009-01-01

    The progress in the field of affective computing enables the realization of affective consumer products, affective games, and affective art. This paper describes the affective interactive art system Mood Swings, which interprets and visualizes affect expressed by a person. Mood Swings is founded on

  8. Mood Swings: An Affective Interactive Art System

    NARCIS (Netherlands)

    Bialoskorski, Leticia S.S.; Westerink, Joyce H.D.M.; Broek, van den Egon L.; Nijholt, Anton; Reidsma, Dennis; Hondorp, Hendri

    2009-01-01

    The progress in the field of affective computing enables the realization of affective consumer products, affective games, and affective art. This paper describes the affective interactive art system Mood Swings, which interprets and visualizes affect expressed by a person. Mood Swings is founded on

  9. Come, See and Experience Affective Interactive Art

    NARCIS (Netherlands)

    Bialoskorski, Leticia S.S.; Westerink, Joyce H.D.M.; Broek, van den Egon L.; Nijholt, A.; Reidsma, D.; Hondorp, G.H.W.

    2009-01-01

    The progress in the field of affective computing enables the realization of affective consumer products, affective games, and affective art. This paper describes the affective interactive art system Mood Swings, which interprets and visualizes affect expressed by a person. Mood Swings is founded on

  10. Treatment of Plasmodium chabaudi Parasites with Curcumin in Combination with Antimalarial Drugs: Drug Interactions and Implications on the Ubiquitin/Proteasome System

    OpenAIRE

    Zoraima Neto; Marta Machado; Ana Lindeza; Virgílio do Rosário; Gazarini, Marcos L.; Dinora Lopes

    2013-01-01

    Antimalarial drug resistance remains a major obstacle in malaria control. Evidence from Southeast Asia shows that resistance to artemisinin combination therapy (ACT) is inevitable. Ethnopharmacological studies have confirmed the efficacy of curcumin against Plasmodium spp. Drug interaction assays between curcumin/piperine/chloroquine and curcumin/piperine/artemisinin combinations and the potential of drug treatment to interfere with the ubiquitin proteasome system (UPS) were analyzed. In vivo...

  11. Mood Swings: An Affective Interactive Art System

    Science.gov (United States)

    Bialoskorski, Leticia S. S.; Westerink, Joyce H. D. M.; van den Broek, Egon L.

    The progress in the field of affective computing enables the realization of affective consumer products, affective games, and affective art. This paper describes the affective interactive art system Mood Swings, which interprets and visualizes affect expressed by a person. Mood Swings is founded on the integration of a framework for affective movements and a color model. This enables Mood Swings to recognize affective movement characteristics as expressed by a person and display a color that matches the expressed emotion. With that, a unique interactive system is introduced, which can be considered as art, a game, or a combination of both.

  12. Nonverbal synchrony and affect in dyadic interactions

    Directory of Open Access Journals (Sweden)

    Wolfgang eTschacher

    2014-11-01

    Full Text Available In an experiment on dyadic social interaction, we invited participants to verbal interactions in cooperative, competitive, and 'fun task' conditions. We focused on the link between interactants' affectivity and their nonverbal synchrony, and explored which further variables contributed to affectivity: interactants' personality traits, sex, and the prescribed interaction tasks. Nonverbal synchrony was quantified by the coordination of interactants' body movement, using an automated video-analysis algorithm (Motion Energy Analysis, MEA. Traits were assessed with standard questionnaires of personality, attachment, interactional style, psychopathology and interpersonal reactivity. We included 168 previously unacquainted individuals who were randomly allocated to same-sex dyads (84 females, 84 males, mean age 27.3 years. Dyads discussed four topics of general interest drawn from an urn of eight topics, and finally engaged in a fun interaction. Each interaction lasted five minutes. In between interactions, participants repeatedly assessed their affect. Using hierarchical linear modeling, we found moderate to strong effect sizes for synchrony to occur, especially in competitive and fun task conditions. Positive affect was associated positively with synchrony, negative affect was associated negatively. As for causal direction, data supported the interpretation that synchrony entailed affect rather than vice versa. The link between nonverbal synchrony and affect was strongest in female dyads. The findings extend previous reports of synchrony and mimicry associated with emotion in relationships and suggest a possible mechanism of the synchrony-affect correlation.

  13. Shear-affected depletion interaction

    NARCIS (Netherlands)

    July, C.; Kleshchanok, D.; Lang, P.R.

    2012-01-01

    We investigate the influence of flow fields on the strength of the depletion interaction caused by disc-shaped depletants. At low mass concentration of discs, it is possible to continuously decrease the depth of the depletion potential by increasing the applied shear rate until the depletion force i

  14. Inhibition of the host proteasome facilitates papaya ringspot virus accumulation and proteosomal catalytic activity is modulated by viral factor HcPro.

    Directory of Open Access Journals (Sweden)

    Nandita Sahana

    Full Text Available The ubiquitin/26S proteasome system plays an essential role not only in maintaining protein turnover, but also in regulating many other plant responses, including plant-pathogen interactions. Previous studies highlighted different roles of the 20S proteasome in plant defense during virus infection, either indirectly through viral suppressor-mediated degradation of Argonaute proteins, affecting the RNA interference pathway, or directly through modulation of the proteolytic and RNase activity of the 20S proteasome, a component of the 20S proteasome, by viral proteins, affecting the levels of viral proteins and RNAs. Here we show that MG132, a cell permeable proteasomal inhibitor, caused an increase in papaya ringspot virus (PRSV accumulation in its natural host papaya (Carica papaya. We also show that the PRSV HcPro interacts with the papaya homologue of the Arabidopsis PAA (α1 subunit of the 20S proteasome, but not with the papaya homologue of Arabidopsis PAE (α5 subunit of the 20S proteasome, associated with the RNase activity, although the two 20S proteasome subunits interacted with each other. Mutated forms of PRSV HcPro showed that the conserved KITC54 motif in the N-terminal domain of HcPro was necessary for its binding to PAA. Co-agroinfiltration assays demonstrated that HcPro expression mimicked the action of MG132, and facilitated the accumulation of bothtotal ubiquitinated proteins and viral/non-viral exogenous RNA in Nicotiana benthamiana leaves. These effects were not observed by using an HcPro mutant (KITS54, which impaired the HcPro - PAA interaction. Thus, the PRSV HcPro interacts with a proteasomal subunit, inhibiting the action of the 20S proteasome, suggesting that HcPro might be crucial for modulating its catalytic activities in support of virus accumulation.

  15. HUWE1 interacts with BRCA1 and promotes its degradation in the ubiquitin–proteasome pathway (Biochemical and Biophysical Research Communications, v. 444 issue 3)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaozhen [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China); Lu, Guang; Li, Li; Yi, Juan; Yan, Kaowen; Wang, Yaqing; Zhu, Baili; Kuang, Jingyu; Lin, Ming; Zhang, Sha [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Shao, Genze, E-mail: gzshao@bjmu.edu.cn [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China)

    2014-02-14

    Highlights: • The 2000–2634 aa region of HUWE1 mediates the interaction with BRCA1 degron. • HUWE1 promotes the degradation of BRCA1 through the ubiquitin–proteasome pathway. • HUWE1 expression is inversely correlated with BRCA1 in breast cancer cells. • RNAi inhibition of HUWE1 confers increased resistance of MCF-10F cells to IR and MMC. - Abstract: The cellular BRCA1 protein level is essential for its tumor suppression activity and is tightly regulated through multiple mechanisms including ubiquitn–proteasome system. E3 ligases are involved to promote BRCA1 for ubiquitination and degradation. Here, we identified HUWE1/Mule/ARF-BP1 as a novel BRCA1-interacting protein involved in the control of BRCA1 protein level. HUWE1binds BRCA1 through its N-terminus degron domain. Depletion of HUWE1 by siRNA-mediated interference significantly increases BRCA1 protein levels and prolongs the half-life of BRCA1. Moreover, exogenous expression of HUWE1 promotes BRCA1 degradation through the ubiquitin–proteasome pathway, which could explain an inverse correlation between HUWE1 and BRCA1 levels in MCF10F, MCF7 and MDA-MB-231 breast cancer cells. Consistent with a functional role for HUWE1 in regulating BRCA1-mediated cellular response to DNA damage, depletion of HUWE1 by siRNA confers increased resistance to ionizing radiation and mitomycin. These data indicate that HUWE1 is a critical negative regulator of BRCA1 and suggest a new molecular mechanism for breast cancer pathogenesis.

  16. HUWE1 interacts with BRCA1 and promotes its degradation in the ubiquitin–proteasome pathway (Biochemical and Biophysical Research Communications, v. 444, isse 4)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaozhen [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China); Lu, Guang; Li, Li; Yi, Juan; Yan, Kaowen; Wang, Yaqing; Zhu, Baili; Kuang, Jingyu; Lin, Ming; Zhang, Sha [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Shao, Genze, E-mail: gzshao@bjmu.edu.cn [Department of Cell Biology, Peking University Health Science Center, Beijing 100191 (China); Institute of Systems Biology, Peking University, Beijing 100191 (China)

    2014-02-21

    Highlights: • The 2000–2634aa region of HUWE1 mediates the interaction with BRCA1 degron. • HUWE1 promotes the degradation of BRCA1 through the ubiquitin–proteasome pathway. • HUWE1 expression is inversely correlated with BRCA1 in breast cancer cells. • RNAi inhibition of HUWE1 confers increased resistance of MCF-10F cells to IR and MMC. - Abstract: The cellular BRCA1 protein level is essential for its tumor suppression activity and is tightly regulated through multiple mechanisms including ubiquitn–proteasome system. E3 ligases are involved to promote BRCA1 for ubiquitination and degradation. Here, we identified HUWE1/Mule/ARF-BP1 as a novel BRCA1-interacting protein involved in the control of BRCA1 protein level. HUWE1 binds BRCA1 through its N-terminus degron domain. Depletion of HUWE1 by siRNA-mediated interference significantly increases BRCA1 protein levels and prolongs the half-life of BRCA1. Moreover, exogenous expression of HUWE1 promotes BRCA1 degradation through the ubiquitin–proteasome pathway, which could explain an inverse correlation between HUWE1 and BRCA1 levels in MCF10F, MCF7 and MDA-MB-231 breast cancer cells. Consistent with a functional role for HUWE1 in regulating BRCA1-mediated cellular response to DNA damage, depletion of HUWE1 by siRNA confers increased resistance to ionizing radiation and mitomycin. These data indicate that HUWE1 is a critical negative regulator of BRCA1 and suggest a new molecular mechanism for breast cancer pathogenesis.

  17. Proteasome inhibitor treatment in alcoholic liver disease

    Institute of Scientific and Technical Information of China (English)

    Fawzia Bardag-Gorce

    2011-01-01

    Oxidative stress, generated by chronic ethanol consumption, is a major cause of hepatotoxicity and liver injury. Increased production of oxygen-derived free radicals due to ethanol metabolism by CYP2E1 is principally located in the cytoplasm and in the mitochondria, which does not only injure liver cells, but also other vital organs, such as the heart and the brain. Therefore, there is a need for better treatment to enhance the antioxidant response elements. To date, there is no established treatment to attenuate high levels of oxidative stress in the liver of alcoholic patients. To block this oxidative stress, proteasome inhibitor treatment has been found to significantly enhance the antioxidant response elements of hepatocytes exposed to ethanol. Recent studies have shown in an experimental model of alcoholic liver disease that proteasome inhibitor treatment at low dose has cytoprotective effects against ethanol-induced oxidative stress and liver steatosis. The beneficial effects of proteasome inhibitor treatment against oxidative stress occurred because antioxidant response elements (glutathione peroxidase 2, superoxide dismutase 2, glutathione synthetase, glutathione reductase, and GCLC) were upregulated when rats fed alcohol were treated with a low dose of PS-341 (Bortezomib, Velcade(r)). This is an important finding because proteasome inhibitor treatment up-regulated reactive oxygen species removal and glutathione recycling enzymes, while ethanol feeding alone down-regulated these antioxidant elements. For the first time, it was shown that proteasome inhibition by a highly specific and reversible inhibitor is different from the chronic ethanol feeding-induced proteasome inhibition. As previously shown by our group, chronic ethanol feeding causes a complex dysfunction in the ubiquitin proteasome pathway, which affects the proteasome system, as well as the ubiquitination system. The beneficial effects of proteasome inhibitor treatment in alcoholic liver disease

  18. Affective loop experiences: designing for interactional embodiment.

    Science.gov (United States)

    Höök, Kristina

    2009-12-12

    Involving our corporeal bodies in interaction can create strong affective experiences. Systems that both can be influenced by and influence users corporeally exhibit a use quality we name an affective loop experience. In an affective loop experience, (i) emotions are seen as processes, constructed in the interaction, starting from everyday bodily, cognitive or social experiences; (ii) the system responds in ways that pull the user into the interaction, touching upon end users' physical experiences; and (iii) throughout the interaction the user is an active, meaning-making individual choosing how to express themselves-the interpretation responsibility does not lie with the system. We have built several systems that attempt to create affective loop experiences with more or less successful results. For example, eMoto lets users send text messages between mobile phones, but in addition to text, the messages also have colourful and animated shapes in the background chosen through emotion-gestures with a sensor-enabled stylus pen. Affective Diary is a digital diary with which users can scribble their notes, but it also allows for bodily memorabilia to be recorded from body sensors mapping to users' movement and arousal and placed along a timeline. Users can see patterns in their bodily reactions and relate them to various events going on in their lives. The experiences of building and deploying these systems gave us insights into design requirements for addressing affective loop experiences, such as how to design for turn-taking between user and system, how to create for 'open' surfaces in the design that can carry users' own meaning-making processes, how to combine modalities to create for a 'unity' of expression, and the importance of mirroring user experience in familiar ways that touch upon their everyday social and corporeal experiences. But a more important lesson gained from deploying the systems is how emotion processes are co-constructed and experienced

  19. CaMKII, but not protein kinase A, regulates Rpt6 phosphorylation and proteasome activity during the formation of long-term memories

    Directory of Open Access Journals (Sweden)

    Timothy J Jarome

    2013-08-01

    Full Text Available CaMKII and Protein Kinase A (PKA are thought to be critical for synaptic plasticity and memory formation through their regulation of protein synthesis. Consistent with this, numerous studies have reported that CaMKII, PKA and protein synthesis are critical for long-term memory formation. Recently, we found that protein degradation through the ubiquitin-proteasome system is also critical for long-term memory formation in the amygdala. However, the mechanism by which ubiquitin-proteasome activity is regulated during memory formation and how protein degradation interacts with known intracellular signaling pathways important for learning remain unknown. Recently, evidence has emerged suggesting that both CaMKII and PKA are capable of regulating proteasome activity in vitro through the phosphorylation of proteasome regulatory subunit Rpt6 at Serine-120, though whether they regulate Rpt6 phosphorylation and proteasome function in vivo remains unknown. In the present study we demonstrate for the first time that fear conditioning transiently modifies a proteasome regulatory subunit and proteasome catalytic activity in the mammalian brain in a CaMKII-dependent manner. We found increases in the phosphorylation of proteasome ATPase subunit Rpt6 at Serine-120 and an enhancement in proteasome activity in the amygdala following fear conditioning. Pharmacological manipulation of CaMKII, but not PKA, in vivo significantly reduced both the learning-induced increase in Rpt6 Serine-120 phosphorylation and the increase in proteasome activity without directly affecting protein polyubiquitination levels. These results indicate a novel role for CaMKII in memory formation through its regulation of protein degradation and suggest that CaMKII regulates Rpt6 phosphorylation and proteasome function both in vitro and in vivo.

  20. Genetics of Proteasome Diseases

    Directory of Open Access Journals (Sweden)

    Aldrin V. Gomes

    2013-01-01

    Full Text Available The proteasome is a large, multiple subunit complex that is capable of degrading most intracellular proteins. Polymorphisms in proteasome subunits are associated with cardiovascular diseases, diabetes, neurological diseases, and cancer. One polymorphism in the proteasome gene PSMA6 (−8C/G is associated with three different diseases: type 2 diabetes, myocardial infarction, and coronary artery disease. One type of proteasome, the immunoproteasome, which contains inducible catalytic subunits, is adapted to generate peptides for antigen presentation. It has recently been shown that mutations and polymorphisms in the immunoproteasome catalytic subunit PSMB8 are associated with several inflammatory and autoinflammatory diseases including Nakajo-Nishimura syndrome, CANDLE syndrome, and intestinal M. tuberculosis infection. This comprehensive review describes the disease-related polymorphisms in proteasome genes associated with human diseases and the physiological modulation of proteasome function by these polymorphisms. Given the large number of subunits and the central importance of the proteasome in human physiology as well as the fast pace of detection of proteasome polymorphisms associated with human diseases, it is likely that other polymorphisms in proteasome genes associated with diseases will be detected in the near future. While disease-associated polymorphisms are now readily discovered, the challenge will be to use this genetic information for clinical benefit.

  1. Bacterial proteasome activator bpa (rv3780 is a novel ring-shaped interactor of the mycobacterial proteasome.

    Directory of Open Access Journals (Sweden)

    Cyrille L Delley

    Full Text Available The occurrence of the proteasome in bacteria is limited to the phylum of actinobacteria, where it is maintained in parallel to the usual bacterial compartmentalizing proteases. The role it plays in these organisms is still not fully understood, but in the human pathogen Mycobacterium tuberculosis (Mtb the proteasome supports persistence in the host. In complex with the ring-shaped ATPase Mpa (called ARC in other actinobacteria, the proteasome can degrade proteins that have been post-translationally modified with the prokaryotic ubiquitin-like protein Pup. Unlike for the eukaryotic proteasome core particle, no other bacterial proteasome interactors have been identified to date. Here we describe and characterize a novel bacterial proteasome activator of Mycobacterium tuberculosis we termed Bpa (Rv3780, using a combination of biochemical and biophysical methods. Bpa features a canonical C-terminal proteasome interaction motif referred to as the HbYX motif, and its orthologs are only found in those actinobacteria encoding the proteasomal subunits. Bpa can inhibit degradation of Pup-tagged substrates in vitro by competing with Mpa for association with the proteasome. Using negative-stain electron microscopy, we show that Bpa forms a ring-shaped homooligomer that can bind coaxially to the face of the proteasome cylinder. Interestingly, Bpa can stimulate the proteasomal degradation of the model substrate β-casein, which suggests it could play a role in the removal of non-native or damaged proteins.

  2. Bacterial proteasome activator bpa (rv3780) is a novel ring-shaped interactor of the mycobacterial proteasome.

    Science.gov (United States)

    Delley, Cyrille L; Laederach, Juerg; Ziemski, Michal; Bolten, Marcel; Boehringer, Daniel; Weber-Ban, Eilika

    2014-01-01

    The occurrence of the proteasome in bacteria is limited to the phylum of actinobacteria, where it is maintained in parallel to the usual bacterial compartmentalizing proteases. The role it plays in these organisms is still not fully understood, but in the human pathogen Mycobacterium tuberculosis (Mtb) the proteasome supports persistence in the host. In complex with the ring-shaped ATPase Mpa (called ARC in other actinobacteria), the proteasome can degrade proteins that have been post-translationally modified with the prokaryotic ubiquitin-like protein Pup. Unlike for the eukaryotic proteasome core particle, no other bacterial proteasome interactors have been identified to date. Here we describe and characterize a novel bacterial proteasome activator of Mycobacterium tuberculosis we termed Bpa (Rv3780), using a combination of biochemical and biophysical methods. Bpa features a canonical C-terminal proteasome interaction motif referred to as the HbYX motif, and its orthologs are only found in those actinobacteria encoding the proteasomal subunits. Bpa can inhibit degradation of Pup-tagged substrates in vitro by competing with Mpa for association with the proteasome. Using negative-stain electron microscopy, we show that Bpa forms a ring-shaped homooligomer that can bind coaxially to the face of the proteasome cylinder. Interestingly, Bpa can stimulate the proteasomal degradation of the model substrate β-casein, which suggests it could play a role in the removal of non-native or damaged proteins. PMID:25469515

  3. Treatment of Plasmodium chabaudi Parasites with Curcumin in Combination with Antimalarial Drugs: Drug Interactions and Implications on the Ubiquitin/Proteasome System

    Directory of Open Access Journals (Sweden)

    Zoraima Neto

    2013-01-01

    Full Text Available Antimalarial drug resistance remains a major obstacle in malaria control. Evidence from Southeast Asia shows that resistance to artemisinin combination therapy (ACT is inevitable. Ethnopharmacological studies have confirmed the efficacy of curcumin against Plasmodium spp. Drug interaction assays between curcumin/piperine/chloroquine and curcumin/piperine/artemisinin combinations and the potential of drug treatment to interfere with the ubiquitin proteasome system (UPS were analyzed. In vivo efficacy of curcumin was studied in BALB/c mice infected with Plasmodium chabaudi clones resistant to chloroquine and artemisinin, and drug interactions were analyzed by isobolograms. Subtherapeutic doses of curcumin, chloroquine, and artemisinin were administered to mice, and mRNA was collected following treatment for RT-PCR analysis of genes encoding deubiquitylating enzymes (DUBs. Curcumin was found be nontoxic in BALB/c mice. The combination of curcumin/chloroquine/piperine reduced parasitemia to 37% seven days after treatment versus the control group’s 65%, and an additive interaction was revealed. Curcumin/piperine/artemisinin combination did not show a favorable drug interaction in this murine model of malaria. Treatment of mice with subtherapeutic doses of the drugs resulted in a transient increase in genes encoding DUBs indicating UPS interference. If curcumin is to join the arsenal of available antimalarial drugs, future studies exploring suitable drug partners would be of interest.

  4. E3 ubiquitin ligase CHIP interacts with C-type lectin-like receptor CLEC-2 and promotes its ubiquitin-proteasome degradation.

    Science.gov (United States)

    Shao, Miaomiao; Li, Lili; Song, Shushu; Wu, Weicheng; Peng, Peike; Yang, Caiting; Zhang, Mingming; Duan, Fangfang; Jia, Dongwei; Zhang, Jie; Wu, Hao; Zhao, Ran; Wang, Lan; Ruan, Yuanyuan; Gu, Jianxin

    2016-10-01

    C-type lectin-like receptor 2 (CLEC-2) was originally identified as a member of non-classical C-type lectin-like receptors in platelets and immune cells. Activation of CLEC-2 is involved in thrombus formation, lymphatic/blood vessel separation, platelet-mediated tumor metastasis and immune response. Nevertheless, the regulation of CLEC-2 expression is little understood. In this study, we identified that the C terminus of Hsc70-interacting protein (CHIP) interacted with CLEC-2 by mass spectrometry analysis, and CHIP decreased the protein expression of CLEC-2 through lysine-48-linked ubiquitination and proteasomal degradation. Deleted and point mutation also revealed that CHIP controlled CLEC-2 protein expression via both tetratricopeptide repeats (TPR) domain and Ubox domain in a HSP70/90-independent manner. Moreover, reduced CHIP expression was associated with decreased CLEC-2 polyubiquitination and increased CLEC-2 protein levels in PMA-induced differentiation of THP-1 monocytes into macrophages. These results indicate that CLEC-2 is the target substrate of E3 ubiquitin ligase CHIP, and suggest that the CHIP/CLEC-2 axis may play an important role in the modulation of immune response. PMID:27443248

  5. E3 ubiquitin ligase CHIP interacts with C-type lectin-like receptor CLEC-2 and promotes its ubiquitin-proteasome degradation.

    Science.gov (United States)

    Shao, Miaomiao; Li, Lili; Song, Shushu; Wu, Weicheng; Peng, Peike; Yang, Caiting; Zhang, Mingming; Duan, Fangfang; Jia, Dongwei; Zhang, Jie; Wu, Hao; Zhao, Ran; Wang, Lan; Ruan, Yuanyuan; Gu, Jianxin

    2016-10-01

    C-type lectin-like receptor 2 (CLEC-2) was originally identified as a member of non-classical C-type lectin-like receptors in platelets and immune cells. Activation of CLEC-2 is involved in thrombus formation, lymphatic/blood vessel separation, platelet-mediated tumor metastasis and immune response. Nevertheless, the regulation of CLEC-2 expression is little understood. In this study, we identified that the C terminus of Hsc70-interacting protein (CHIP) interacted with CLEC-2 by mass spectrometry analysis, and CHIP decreased the protein expression of CLEC-2 through lysine-48-linked ubiquitination and proteasomal degradation. Deleted and point mutation also revealed that CHIP controlled CLEC-2 protein expression via both tetratricopeptide repeats (TPR) domain and Ubox domain in a HSP70/90-independent manner. Moreover, reduced CHIP expression was associated with decreased CLEC-2 polyubiquitination and increased CLEC-2 protein levels in PMA-induced differentiation of THP-1 monocytes into macrophages. These results indicate that CLEC-2 is the target substrate of E3 ubiquitin ligase CHIP, and suggest that the CHIP/CLEC-2 axis may play an important role in the modulation of immune response.

  6. Oxidation and interaction of DJ-1 with 20S proteasome in the erythrocytes of early stage Parkinson’s disease patients

    Science.gov (United States)

    Saito, Yoshiro; Akazawa-Ogawa, Yoko; Matsumura, Akihiro; Saigoh, Kazumasa; Itoh, Sayoko; Sutou, Kenta; Kobayashi, Mayuka; Mita, Yuichiro; Shichiri, Mototada; Hisahara, Shin; Hara, Yasuo; Fujimura, Harutoshi; Takamatsu, Hiroyuki; Hagihara, Yoshihisa; Yoshida, Yasukazu; Hamakubo, Takao; Kusunoki, Susumu; Shimohama, Shun; Noguchi, Noriko

    2016-01-01

    Parkinson’s disease (PD) is a progressive, age-related, neurodegenerative disorder, and oxidative stress is an important mediator in its pathogenesis. DJ-1, the product of the causative gene of a familial form of PD, plays a significant role in anti-oxidative defence to protect cells from oxidative stress. DJ-1 undergoes preferential oxidation at the cysteine residue at position 106 (Cys-106) under oxidative stress. Here, using specific antibodies against Cys-106-oxidized DJ-1 (oxDJ-1), it was found that the levels of oxDJ-1 in the erythrocytes of unmedicated PD patients (n = 88) were higher than in those of medicated PD patients (n = 62) and healthy control subjects (n = 33). Elevated oxDJ-1 levels were also observed in a non-human primate PD model. Biochemical analysis of oxDJ-1 in erythrocyte lysates showed that oxDJ-1 formed dimer and polymer forms, and that the latter interacts with 20S proteasome. These results clearly indicate a biochemical alteration in the blood of PD patients, which could be utilized as an early diagnosis marker for PD. PMID:27470541

  7. Mood swings: design and evaluation of affective interactive art

    NARCIS (Netherlands)

    Bialoskorski, Leticia S.S.; Westerink, Joyce H.D.M.; Broek, van den Egon L.

    2009-01-01

    The field of affective computing is concerned with developing emphatic products, such as affective consumer products, affective games, and affective art. This paper describes Mood Swings, an affective interactive art system, which interprets and visualizes affect expressed by a person. Mood Swings c

  8. The Corepressor mSin3a Interacts with the Proline-Rich Domain of p53 and Protects p53 from Proteasome-Mediated Degradation

    Science.gov (United States)

    Zilfou, Jack T.; Hoffman, William H.; Sank, Michael; George, Donna L.; Murphy, Maureen

    2001-01-01

    While the transactivation function of the tumor suppressor p53 is well understood, less is known about the transrepression functions of this protein. We have previously shown that p53 interacts with the corepressor protein mSin3a (hereafter designated Sin3) in vivo and that this interaction is critical for the ability of p53 to repress gene expression. In the present study, we demonstrate that expression of Sin3 results in posttranslational stabilization of both exogenous and endogenous p53, due to an inhibition of proteasome-mediated degradation of this protein. Stabilization of p53 by Sin3 requires the Sin3-binding domain, determined here to map to the proline-rich region of p53, from amino acids 61 to 75. The correlation between Sin3 binding and stabilization supports the hypothesis that this domain of p53 may normally be subject to a destabilizing influence. The finding that a synthetic mutant of p53 lacking the Sin3-binding domain has an increased half-life in cells, compared to wild-type p53, supports this premise. Interestingly, unlike retinoblastoma tumor suppressor protein, MDMX, and p14ARF, Sin3 stabilizes p53 in an MDM2-independent manner. The ability of Sin3 to stabilize p53 is consistent with the model whereby these two proteins must exist on a promoter for extended periods, in order for repression to be an effective mechanism of gene regulation. This model is consistent with our data indicating that, unlike the p300-p53 complex, the p53-Sin3 complex is immunologically detectable for prolonged periods following exposure of cells to agents of DNA damage. PMID:11359905

  9. Epidermal Growth Factor Cytoplasmic Domain Affects ErbB Protein Degradation by the Lysosomal and Ubiquitin-Proteasome Pathway in Human Cancer Cells

    Directory of Open Access Journals (Sweden)

    Aleksandra Glogowska

    2012-05-01

    Full Text Available The cytoplasmic domains of EGF-like ligands, including EGF cytoplasmic domain (EGFcyt, have important biological functions. Using specific constructs and peptides of human EGF cytoplasmic domain, we demonstrate that EGFcyt facilitates lysosomal and proteasomal protein degradation, and this coincided with growth inhibition of human thyroid and glioma carcinoma cells. EGFcyt and exon 22–23-encoded peptide (EGF22.23 enhanced procathepsin B (procathB expression and procathB-mediated lysosomal degradation of EGFR/ErbB1 as determined by inhibitors for procathB and the lysosomal ATPase inhibitor BafA1. Presence of mbEGFctF, EGFcyt, EGF22.23, and exon 23-encoded peptides suppressed the expression of the deubiqitinating enzyme ubiquitin C-terminal hydrolase-L1 (UCH-L1. This coincided with hyperubiquitination of total cellular proteins and ErbB1/2 and reduced proteasome activity. Upon small interfering RNA-mediated silencing of endogenously expressed UCH-L1, a similar hyperubiquitinylation phenotype, reduced ErbB1/2 content, and attenuated growth was observed. The exon 23-encoded peptide region of EGFcyt was important for these biologic actions. Structural homology modeling of human EGFcyt showed that this molecular region formed an exposed surface loop. Peptides derived from this EGFcyt loop structure may aid in the design of novel peptide therapeutics aimed at inhibiting growth of cancer cells.

  10. Cysteine string protein promotes proteasomal degradation of the cystic fibrosis transmembrane conductance regulator (CFTR) by increasing its interaction with the C terminus of Hsp70-interacting protein and promoting CFTR ubiquitylation.

    Science.gov (United States)

    Schmidt, Béla Z; Watts, Rebecca J; Aridor, Meir; Frizzell, Raymond A

    2009-02-13

    Cysteine string protein (Csp) is a J-domain-containing protein whose overexpression blocks the exit of cystic fibrosis transmembrane conductance regulator (CFTR) from the endoplasmic reticulum (ER). Another method of blocking ER exit, the overexpression of Sar1-GTP, however, yielded twice as much immature CFTR compared with Csp overexpression. This finding suggested that Csp not only inhibits CFTR ER exit but also facilitates the degradation of immature CFTR. This was confirmed by treatment with a proteasome inhibitor, which returned the level of immature CFTR to that found in cells expressing Sar1-GTP only. CspH43Q, which does not interact with Hsc70/Hsp70 efficiently, did not promote CFTR degradation, suggesting that the pro-degradative effect of Csp requires Hsc70/Hsp70 binding/activation. In agreement with this, Csp overexpression increased the amount of Hsc70/Hsp70 co-immunoprecipitated with CFTR, whereas overexpression of CspH43Q did not. The Hsc70/Hsp70 binding partner C terminus of Hsp70-interacting protein (CHIP) can target CFTR for proteasome-mediated degradation. Csp overexpression also increased the amount of CHIP co-immunoprecipitated with CFTR. In addition, CHIP interacted directly with Csp, which was confirmed by in vitro binding experiments. Csp overexpression also increased CFTR ubiquitylation and reduced the half-life of immature CFTR. These findings indicate that Csp not only regulates the exit of CFTR from the ER, but that this action is accompanied by Hsc70/Hsp70 and CHIP-mediated CFTR degradation.

  11. Sequence analysis of β-subunit genes of the 20S proteasome in patients with relapsed multiple myeloma treated with bortezomib or dexamethasone

    NARCIS (Netherlands)

    D.I. Lichter (David); H. Danaee (Hadi); M.D. Pickard (Michael); O. Tayber (Olga); M. Sintchak (Michael); H. Shi (Hongliang); P.G. Richardson (Paul Gerard); J. Cavenagh (Jamie); J. Bladé (Joan); T. Facon (Thierry); R. Niesvizky; M. Alsina (Melissa); W. Dalton (William); P. Sonneveld (Pieter); S. Lonial (Sagar); H. van de Velde (Helgi); D. Ricci (Deborah); D.-L. Esseltine (Dixie-Lee); W.L. Trepicchio (William); G. Mulligan (George); K.C. Anderson (Kenneth Carl)

    2012-01-01

    textabstractVariations within proteasome β (PSMB) genes, which encode the β subunits of the 20S proteasome, may affect proteasome function, assembly, and/or binding of proteasome inhibitors. To investigate the potential association between PSMB gene variants and treatment-emergent resistance to bort

  12. Negative Affect in Human Robot Interaction

    DEFF Research Database (Denmark)

    Rehm, Matthias; Krogsager, Anders

    2013-01-01

    The vision of social robotics sees robots moving more and more into unrestricted social environments, where robots interact closely with users in their everyday activities, maybe even establishing relationships with the user over time. In this paper we present a field trial with a robot in a semi......-public place. Our analysis of the interactions with casual users shows that it is not enough to focus on modeling behavior that is similar to successful human interactions but that we have to take more deviant ways of interaction like abuse and impoliteness into account when we send robots into the users......’ environments. The analysis uses impoliteness theory as an analytical toolbox and exemplifies which strategies are employed by users in unexpected encounters with a humanoid robot....

  13. APC/C and retinoblastoma interaction: cross-talk of retinoblastoma protein with the ubiquitin proteasome pathway

    Science.gov (United States)

    Ramanujan, Ajeena; Tiwari, Swati

    2016-01-01

    The ubiquitin (Ub) ligase anaphase promoting complex/cyclosome (APC/C) and the tumour suppressor retinoblastoma protein (pRB) play key roles in cell cycle regulation. APC/C is a critical regulator of mitosis and G1-phase of the cell cycle whereas pRB keeps a check on proliferation by inhibiting transition to the S-phase. APC/C and pRB interact with each other via the co-activator of APC/C, FZR1, providing an alternative pathway of regulation of G1 to S transition by pRB using a post-translational mechanism. Both pRB and FZR1 have complex roles and are implicated not only in regulation of cell proliferation but also in differentiation, quiescence, apoptosis, maintenance of chromosomal integrity and metabolism. Both are also targeted by transforming viruses. We discuss recent advances in our understanding of the involvement of APC/C and pRB in cell cycle based decisions and how these insights will be useful for development of anti-cancer and anti-viral drugs. PMID:27402801

  14. Interactive affective sharing versus non-interactive affective sharing in work groups : Comparative effects of group affect on work group performance and dynamics

    NARCIS (Netherlands)

    Klep, Annefloor; Wisse, Barbara; Van Der Flier, Henk

    2011-01-01

    This study explores whether the dynamic path to group affect, which is characterized by interactive affective sharing processes, yields different effects on task performance and group dynamics than the static path to group affect, which arises from non-interactive affective sharing. The results of o

  15. Affective Computing used in an imaging interaction paradigm

    DEFF Research Database (Denmark)

    Schultz, Nette

    2003-01-01

    This paper combines affective computing with an imaging interaction paradigm. An imaging interaction paradigm means that human and computer communicates primarily by images. Images evoke emotions in humans, so the computer must be able to behave emotionally intelligent. An affective image selection...

  16. Drug-drug interactions affecting fluoroquinolones.

    Science.gov (United States)

    Wijnands, G J; Vree, T B; Janssen, T J; Guelen, P J

    1989-12-29

    In a three-week study, the metabolism of the bronchodilator theophylline and its major metabolites formed by C-8 oxidation (1,3-dimethyluric acid) and N-demethylation (3-methylxanthine and 1-methyluric acid) was investigated in two healthy volunteers. Metabolic studies were performed following intravenous infusion of a single 6 mg/kg dose of aminophylline. During Week 1, theophylline was given alone (blank period), and during Weeks 2 and 3 it was given during oral coadministration of ofloxacin and enoxacin, respectively. Dosage of each quinolone was 200 mg twice daily for four days, starting three days prior to the theophylline infusion. During enoxacin coadministration, elimination half-lives of theophylline increased from 8.7 to 17.4 hours and from 6.1 to 12.3 hours, respectively. Total body clearance of theophylline decreased in both volunteers, whereas renal clearance did not alter. From this it was concluded that the decreased elimination results from a reduced metabolic clearance. During enoxacin coadministration, the formation of the metabolites 1-methyluric acid and 3-methylxanthine clearly was decreased, whereas the formation of 1,3-dimethyluric acid was less affected compared with the blank period. Interference with theophylline disposition by enoxacin is based predominantly on inhibition of microsomal N-demethylation. Ofloxacin comedication did not cause a change in the plasma parameters or renal excretion of theophylline and its metabolites compared with the blank period. PMID:2603893

  17. Association of plasminogen activator inhibitor type 2 (PAI-2) with proteasome within endothelial cells activated with inflammatory stimuli.

    Science.gov (United States)

    Boncela, Joanna; Przygodzka, Patrycja; Papiewska-Pajak, Izabela; Wyroba, Elzbieta; Cierniewski, Czeslaw S

    2011-12-16

    Quiescent endothelial cells contain low concentrations of plasminogen activator inhibitor type 2 (PAI-2). However, its synthesis can be rapidly stimulated by a variety of inflammatory mediators. In this study, we provide evidence that PAI-2 interacts with proteasome and affects its activity in endothelial cells. To ensure that the PAI-2·proteasome complex is formed in vivo, both proteins were coimmunoprecipitated from endothelial cells and identified with specific antibodies. The specificity of this interaction was evidenced after (a) transfection of HeLa cells with pCMV-PAI-2 and coimmunoprecipitation of both proteins with anti-PAI-2 antibodies and (b) silencing of the PAI-2 gene using specific small interfering RNA (siRNA). Subsequently, cellular distribution of the PAI-2·proteasome complexes was established by immunogold staining and electron microscopy analyses. As judged by confocal microscopy, both proteins appeared in a diffuse cytosolic pattern, but they also could be found in a dense perinuclear and nuclear location. PAI-2 was not polyubiquitinated, suggesting that it bound to proteasome not as the substrate but rather as its inhibitor. Consistently, increased PAI-2 expression (a) abrogated degradation of degron analyzed after cotransfection of HeLa cells with pCMV-PAI-2 and pd2EGFP-N1, (b) prevented degradation of p53, as evidenced both by confocal microscopy and Western immunoblotting, and (c) inhibited proteasome cleavage of specific fluorogenic substrate. This suggests that PAI-2, in endothelial cells induced with inflammatory stimuli, can inhibit proteasome and thus tilt the balance favoring proapoptotic signaling.

  18. Association of Plasminogen Activator Inhibitor Type 2 (PAI-2) with Proteasome within Endothelial Cells Activated with Inflammatory Stimuli*

    Science.gov (United States)

    Boncela, Joanna; Przygodzka, Patrycja; Papiewska-Pajak, Izabela; Wyroba, Elzbieta; Cierniewski, Czeslaw S.

    2011-01-01

    Quiescent endothelial cells contain low concentrations of plasminogen activator inhibitor type 2 (PAI-2). However, its synthesis can be rapidly stimulated by a variety of inflammatory mediators. In this study, we provide evidence that PAI-2 interacts with proteasome and affects its activity in endothelial cells. To ensure that the PAI-2·proteasome complex is formed in vivo, both proteins were coimmunoprecipitated from endothelial cells and identified with specific antibodies. The specificity of this interaction was evidenced after (a) transfection of HeLa cells with pCMV-PAI-2 and coimmunoprecipitation of both proteins with anti-PAI-2 antibodies and (b) silencing of the PAI-2 gene using specific small interfering RNA (siRNA). Subsequently, cellular distribution of the PAI-2·proteasome complexes was established by immunogold staining and electron microscopy analyses. As judged by confocal microscopy, both proteins appeared in a diffuse cytosolic pattern, but they also could be found in a dense perinuclear and nuclear location. PAI-2 was not polyubiquitinated, suggesting that it bound to proteasome not as the substrate but rather as its inhibitor. Consistently, increased PAI-2 expression (a) abrogated degradation of degron analyzed after cotransfection of HeLa cells with pCMV-PAI-2 and pd2EGFP-N1, (b) prevented degradation of p53, as evidenced both by confocal microscopy and Western immunoblotting, and (c) inhibited proteasome cleavage of specific fluorogenic substrate. This suggests that PAI-2, in endothelial cells induced with inflammatory stimuli, can inhibit proteasome and thus tilt the balance favoring proapoptotic signaling. PMID:21976669

  19. Nuclear Import of Yeast Proteasomes

    Directory of Open Access Journals (Sweden)

    Julianne Burcoglu

    2015-08-01

    Full Text Available Proteasomes are highly conserved protease complexes responsible for the degradation of aberrant and short-lived proteins. In highly proliferating yeast and mammalian cells, proteasomes are predominantly nuclear. During quiescence and cell cycle arrest, proteasomes accumulate in granules in close proximity to the nuclear envelope/ER. With prolonged quiescence in yeast, these proteasome granules pinch off as membraneless organelles, and migrate as stable entities through the cytoplasm. Upon exit from quiescence, the proteasome granules clear and the proteasomes are rapidly transported into the nucleus, a process reflecting the dynamic nature of these multisubunit complexes. Due to the scarcity of studies on the nuclear transport of mammalian proteasomes, we summarised the current knowledge on the nuclear import of yeast proteasomes. This pathway uses canonical nuclear localisation signals within proteasomal subunits and Srp1/Kap95, and the canonical import receptor, named importin/karyopherin αβ. Blm10, a conserved 240 kDa protein, which is structurally related to Kap95, provides an alternative import pathway. Two models exist upon which either inactive precursor complexes or active holo-enzymes serve as the import cargo. Here, we reconcile both models and suggest that the import of inactive precursor complexes predominates in dividing cells, while the import of mature enzymes mainly occurs upon exit from quiescence.

  20. ORF2 protein of porcine circovirus type 2 promotes phagocytic activity of porcine macrophages by inhibiting proteasomal degradation of complement component 1, q subcomponent binding protein (C1QBP) through physical interaction.

    Science.gov (United States)

    Choi, Chang-Yong; Oh, Hae-Na; Lee, Suk Jun; Chun, Taehoon

    2015-11-01

    Defining how each ORF of porcine circovirus type 2 (PCV2) manipulates the host immune system may be helpful to understand the disease progression of post-weaning multisystemic wasting syndrome. In this study, we demonstrated a direct interaction between the PCV2 ORF2 and complement component 1, q subcomponent binding protein (C1QBP) within the cytoplasm of host macrophages. The physical interaction between PCV2 ORF2 and C1QBP inhibited ubiquitin-mediated proteasomal degradation of C1QBP in macrophages. Increased stability of C1QBP by the interaction with PCV2 ORF2 further enhanced the phagocytic activity of porcine macrophages through the phosphoinositol 3-kinase signalling pathway. This may explain the molecular basis of how PCV2 ORF2 enhances the phagocytic activity of host macrophages.

  1. Affective Behavior and Nonverbal Interaction in Collaborative Virtual Environments

    Science.gov (United States)

    Peña, Adriana; Rangel, Nora; Muñoz, Mirna; Mejia, Jezreel; Lara, Graciela

    2016-01-01

    While a person's internal state might not be easily inferred through an automatic computer system, within a group, people express themselves through their interaction with others. The group members' interaction can be then helpful to understand, to certain extent, its members' affective behavior in any case toward the task at hand. In this…

  2. Pyrrolidine dithiocarbamate-zinc(II) and -copper(II) complexes induce apoptosis in tumor cells by inhibiting the proteasomal activity.

    Science.gov (United States)

    Milacic, Vesna; Chen, Di; Giovagnini, Lorena; Diez, Alejandro; Fregona, Dolores; Dou, Q Ping

    2008-08-15

    Zinc and copper are trace elements essential for proper folding, stabilization and catalytic activity of many metalloenzymes in living organisms. However, disturbed zinc and copper homeostasis is reported in many types of cancer. We have previously demonstrated that copper complexes induced proteasome inhibition and apoptosis in cultured human cancer cells. In the current study we hypothesized that zinc complexes could also inhibit the proteasomal chymotrypsin-like activity responsible for subsequent apoptosis induction. We first showed that zinc(II) chloride was able to inhibit the chymotrypsin-like activity of a purified 20S proteasome with an IC(50) value of 13.8 microM, which was less potent than copper(II) chloride (IC(50) 5.3 microM). We then compared the potencies of a pyrrolidine dithiocarbamate (PyDT)-zinc(II) complex and a PyDT-copper(II) complex to inhibit cellular proteasomal activity, suppress proliferation and induce apoptosis in various human breast and prostate cancer cell lines. Consistently, zinc complex was less potent than copper complex in inhibiting the proteasome and inducing apoptosis. Additionally, zinc and copper complexes appear to use somewhat different mechanisms to kill tumor cells. Zinc complexes were able to activate calpain-, but not caspase-3-dependent pathway, while copper complexes were able to induce activation of both proteases. Furthermore, the potencies of these PyDT-metal complexes depend on the nature of metals and also on the ratio of PyDT to the metal ion within the complex, which probably affects their stability and availability for interacting with and inhibiting the proteasome in tumor cells. PMID:18501397

  3. Voluntary exercise may engage proteasome function to benefit the brain after trauma

    OpenAIRE

    Szabo, Zsofia; Ying, Zhe; Radak, Zsolt; Gomez-Pinilla, Fernando

    2009-01-01

    Brain trauma is associated with long-term decrements in synaptic plasticity and cognitive function, which likely reside on the acute effects of the injury on protein structure and function. Based on the action of proteasome on protein synthesis and degradation we have examined the effects of brain injury on proteasome level/activity and the potential of exercise to interact with the effects of the injury. Exercise has a healing ability but its action on proteasome function is not understood. ...

  4. Proteasomes are tightly associated to myofibrils in mature skeletal muscle.

    Science.gov (United States)

    Bassaglia, Yann; Cebrian, José; Covan, Silvia; Garcia, Monica; Foucrier, Jean

    2005-01-15

    Proteasomes are the major actors of nonlysosomal cytoplasmic protein degradation. In particular, these large protein complexes (about 2500 kDa) are considered to be responsible for muscular degradation during skeletal muscle atrophy. Despite their unusual and important size, they are widely described as soluble and mobile in the cytoplasm. In mature skeletal muscle, we have previously observed a sarcomeric distribution of proteasomes, as revealed by the distribution of alpha1/p27K, a subunit of the 20S core-particle (prosome) of proteasome. Here, we extend these observations at the electron microscopic level in vivo. We also show that this sarcomeric pattern is dependent of the extension of the sarcomere. Using isolated myofibrils, we demonstrate that proteasomes are still attached to the myofibrils after the isolation procedure, and reproduce the observations made in vivo. In addition, the extraction of actin by gelsolin largely removes proteasomes from isolated myofibrils, but some of them are held in place after this extraction, showing a sarcomeric disposition in the absence of any detectable actin, and suggesting the existence of another molecular partner for these interactions. From these results, we conclude that most of detectable 20S proteasomes in skeletal muscle cells is tightly attached to the myofibrils. PMID:15561103

  5. The ubiquitin-proteasome system

    Indian Academy of Sciences (India)

    Dipankar Nandi; Pankaj Tahiliani; Anujith Kumar; Dilip Chandu

    2006-03-01

    The 2004 Nobel Prize in chemistry for the discovery of protein ubiquitination has led to the recognition of cellular proteolysis as a central area of research in biology. Eukaryotic proteins targeted for degradation by this pathway are first ‘tagged’ by multimers of a protein known as ubiquitin and are later proteolyzed by a giant enzyme known as the proteasome. This article recounts the key observations that led to the discovery of ubiquitin-proteasome system (UPS). In addition, different aspects of proteasome biology are highlighted. Finally, some key roles of the UPS in different areas of biology and the use of inhibitors of this pathway as possible drug targets are discussed.

  6. Dyclonine and alverine citrate enhance the cytotoxic effects of proteasome inhibitor MG132 on breast cancer cells.

    Science.gov (United States)

    Ju, Donghong; Wang, Xiaogang; Xie, Youming

    2009-02-01

    Proteasome is an important target in cancer therapy. To enhance the efficacy of proteasome inhibitors is a challenging task due to the paucity of understanding the functional interactions between proteasome and other cellular pathways in mammalian cells. Taking advantage of the knowledge gained from Saccharomyces cerevisiae, we show that dyclonine and alverine citrate, the major components of two over-the-counter medicines, can substantially enhance the cytotoxic effects of proteasome inhibitor MG132 on breast cancer cells. This study also highlights an important yeast genetic approach to identification of potential therapeutics that can be used for combination therapy with proteasome inhibitors. PMID:19148544

  7. FMRI scanner noise interaction with affective neural processes.

    Directory of Open Access Journals (Sweden)

    Stavros Skouras

    Full Text Available The purpose of the present study was the investigation of interaction effects between functional MRI scanner noise and affective neural processes. Stimuli comprised of psychoacoustically balanced musical pieces, expressing three different emotions (fear, neutral, joy. Participants (N=34, 19 female were split into two groups, one subjected to continuous scanning and another subjected to sparse temporal scanning that features decreased scanner noise. Tests for interaction effects between scanning group (sparse/quieter vs continuous/noisier and emotion (fear, neutral, joy were performed. Results revealed interactions between the affective expression of stimuli and scanning group localized in bilateral auditory cortex, insula and visual cortex (calcarine sulcus. Post-hoc comparisons revealed that during sparse scanning, but not during continuous scanning, BOLD signals were significantly stronger for joy than for fear, as well as stronger for fear than for neutral in bilateral auditory cortex. During continuous scanning, but not during sparse scanning, BOLD signals were significantly stronger for joy than for neutral in the left auditory cortex and for joy than for fear in the calcarine sulcus. To the authors' knowledge, this is the first study to show a statistical interaction effect between scanner noise and affective processes and extends evidence suggesting scanner noise to be an important factor in functional MRI research that can affect and distort affective brain processes.

  8. Locomotion in Stroke Subjects: Interactions between Unaffected and Affected Sides

    Science.gov (United States)

    Kloter, Evelyne; Wirz, Markus; Dietz, Volker

    2011-01-01

    The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm…

  9. Positive affective interactions: The role of repeated exposure and copresence

    NARCIS (Netherlands)

    Shahid, S.; Krahmer, E.; Neerincx, M.; Swerts, M.

    2013-01-01

    We describe and evaluate a new interface to induce positive emotions in users: a digital, interactive adaptive mirror. We study whether the induced affect is repeatable after a fixed interval (Study 1) and how copresence influences the emotion induction (Study 2). Results show that participants syst

  10. Proteasome Assay in Cell Lysates

    Science.gov (United States)

    Maher, Pamela

    2016-01-01

    The ubiquitin-proteasome system (UPS) mediates the majority of the proteolysis seen in the cytoplasm and nucleus of mammalian cells. As such it plays an important role in the regulation of a variety of physiological and pathophysiological processes including tumorigenesis, inflammation and cell death (Ciechanover, 2005; Kisselev and Goldberg, 2001). A number of recent studies have shown that proteasome activity is decreased in a variety of neurological disorders including Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis and stroke as well as during normal aging (Chung et al., 2001; Ciechanover and Brundin, 2003; Betarbet et al., 2005). This decrease in proteasome activity is thought to play a critical role in the accumulation of abnormal and oxidized proteins. Protein clearance by the UPS involves two sequential reactions. The first is the tagging of protein lysine residues with ubiquitin (Ub) and the second is the subsequent degradation of the tagged proteins by the proteasome. We herein describe an assay for the second of these two reactions (Valera et al., 2013). This assay uses fluorogenic substrates for each of the three activities of the proteasome: chymotrypsin-like activity, trypsin-like activity and caspase-like activity. Cleavage of the fluorophore from the substrate by the proteasome results in fluorescence that can be detected with a fluorescent plate reader.

  11. Immersion in a virtual world interactive drama and affective sciences

    CERN Document Server

    Mayr, Simon

    2014-01-01

    Interactive drama is more than just a new breed of entertainment software. As different research projects have shown, these systems can also be used for pedagogical and therapeutic purposes. The goal of these systems is to teach sophisticated problem solving skills by allowing the user to interact with compelling stories that have didactic purpose.One of the main attractions of narratives, independent of the medium in which they are presented, is that they elicit emotional response in their audiences. They have an affective impact and only engineers and authors who understand how the emotion s

  12. Genetic by environment interactions affect plant–soil linkages

    OpenAIRE

    Pregitzer, Clara C; Joseph K Bailey; Schweitzer, Jennifer A.

    2013-01-01

    The role of plant intraspecific variation in plant–soil linkages is poorly understood, especially in the context of natural environmental variation, but has important implications in evolutionary ecology. We utilized three 18- to 21-year-old common gardens across an elevational gradient, planted with replicates of five Populus angustifolia genotypes each, to address the hypothesis that tree genotype (G), environment (E), and G × E interactions would affect soil carbon and nitrogen dynamics be...

  13. Fate of pup inside the Mycobacterium proteasome studied by in-cell NMR.

    Directory of Open Access Journals (Sweden)

    Andres Y Maldonado

    Full Text Available The Mycobacterium tuberculosis proteasome is required for maximum virulence and to resist killing by the host immune system. The prokaryotic ubiquitin-like protein, Pup-GGE, targets proteins for proteasome-mediated degradation. We demonstrate that Pup-GGQ, a precursor of Pup-GGE, is not a substrate for proteasomal degradation. Using STINT-NMR, an in-cell NMR technique, we studied the interactions between Pup-GGQ, mycobacterial proteasomal ATPase, Mpa, and Mtb proteasome core particle (CP inside a living cell at amino acid residue resolution. We showed that under in-cell conditions, in the absence of the proteasome CP, Pup-GGQ interacts with Mpa only weakly, primarily through its C-terminal region. When Mpa and non-stoichiometric amounts of proteasome CP are present, both the N-terminal and C-terminal regions of Pup-GGQ bind strongly to Mpa. This suggests a mechanism by which transient binding of Mpa to the proteasome CP controls the fate of Pup.

  14. Functions of the Proteasome on Chromatin

    Science.gov (United States)

    McCann, Tyler S.; Tansey, William P.

    2014-01-01

    The proteasome is a large self-compartmentalized protease complex that recognizes, unfolds, and destroys ubiquitylated substrates. Proteasome activities are required for a host of cellular functions, and it has become clear in recent years that one set of critical actions of the proteasome occur on chromatin. In this review, we discuss some of the ways in which proteasomes directly regulate the structure and function of chromatin and chromatin regulatory proteins, and how this influences gene transcription. We discuss lingering controversies in the field, the relative importance of proteolytic versus non-proteolytic proteasome activities in this process, and highlight areas that require further investigation. Our intention is to show that proteasomes are involved in major steps controlling the expression of the genetic information, that proteasomes use both proteolytic mechanisms and ATP-dependent protein remodeling to accomplish this task, and that much is yet to be learned about the full spectrum of ways that proteasomes influence the genome. PMID:25422899

  15. Functions of the Proteasome on Chromatin

    Directory of Open Access Journals (Sweden)

    Tyler S. McCann

    2014-11-01

    Full Text Available The proteasome is a large self-compartmentalized protease complex that recognizes, unfolds, and destroys ubiquitylated substrates. Proteasome activities are required for a host of cellular functions, and it has become clear in recent years that one set of critical actions of the proteasome occur on chromatin. In this review, we discuss some of the ways in which proteasomes directly regulate the structure and function of chromatin and chromatin regulatory proteins, and how this influences gene transcription. We discuss lingering controversies in the field, the relative importance of proteolytic versus non-proteolytic proteasome activities in this process, and highlight areas that require further investigation. Our intention is to show that proteasomes are involved in major steps controlling the expression of the genetic information, that proteasomes use both proteolytic mechanisms and ATP-dependent protein remodeling to accomplish this task, and that much is yet to be learned about the full spectrum of ways that proteasomes influence the genome.

  16. Proteasome Inhibition Suppresses Dengue Virus Egress in Antibody Dependent Infection.

    Science.gov (United States)

    Choy, Milly M; Zhang, Summer L; Costa, Vivian V; Tan, Hwee Cheng; Horrevorts, Sophie; Ooi, Eng Eong

    2015-11-01

    The mosquito-borne dengue virus (DENV) is a cause of significant global health burden, with an estimated 390 million infections occurring annually. However, no licensed vaccine or specific antiviral treatment for dengue is available. DENV interacts with host cell factors to complete its life cycle although this virus-host interplay remains to be fully elucidated. Many studies have identified the ubiquitin proteasome pathway (UPP) to be important for successful DENV production, but how the UPP contributes to DENV life cycle as host factors remains ill defined. We show here that proteasome inhibition decouples infectious virus production from viral RNA replication in antibody-dependent infection of THP-1 cells. Molecular and imaging analyses in β-lactone treated THP-1 cells suggest that proteasome function does not prevent virus assembly but rather DENV egress. Intriguingly, the licensed proteasome inhibitor, bortezomib, is able to inhibit DENV titers at low nanomolar drug concentrations for different strains of all four serotypes of DENV in primary monocytes. Furthermore, bortezomib treatment of DENV-infected mice inhibited the spread of DENV in the spleen as well as the overall pathological changes. Our findings suggest that preventing DENV egress through proteasome inhibition could be a suitable therapeutic strategy against dengue. PMID:26565697

  17. Proteasome Inhibition Suppresses Dengue Virus Egress in Antibody Dependent Infection.

    Directory of Open Access Journals (Sweden)

    Milly M Choy

    2015-11-01

    Full Text Available The mosquito-borne dengue virus (DENV is a cause of significant global health burden, with an estimated 390 million infections occurring annually. However, no licensed vaccine or specific antiviral treatment for dengue is available. DENV interacts with host cell factors to complete its life cycle although this virus-host interplay remains to be fully elucidated. Many studies have identified the ubiquitin proteasome pathway (UPP to be important for successful DENV production, but how the UPP contributes to DENV life cycle as host factors remains ill defined. We show here that proteasome inhibition decouples infectious virus production from viral RNA replication in antibody-dependent infection of THP-1 cells. Molecular and imaging analyses in β-lactone treated THP-1 cells suggest that proteasome function does not prevent virus assembly but rather DENV egress. Intriguingly, the licensed proteasome inhibitor, bortezomib, is able to inhibit DENV titers at low nanomolar drug concentrations for different strains of all four serotypes of DENV in primary monocytes. Furthermore, bortezomib treatment of DENV-infected mice inhibited the spread of DENV in the spleen as well as the overall pathological changes. Our findings suggest that preventing DENV egress through proteasome inhibition could be a suitable therapeutic strategy against dengue.

  18. Pesticide interactions with soils affected by olive oil mill wastewater

    Science.gov (United States)

    Keren, Yonatan; Bukhanovsky, Nadezhda; Borisover, Mikhail

    2013-04-01

    Soil pesticide sorption is well known to affect the fate of pesticides, their bioavailability and the potential to contaminate air and water. Soil - pesticide interactions may be strongly influenced by soil organic matter (SOM) and organic matter (OM)-rich soil amendments. One special OM source in soils is related to olive oil production residues that may include both solid and liquid wastes. In the Mediterranean area, the olive oil production is considered as an important field in the agricultural sector. Due to the significant rise in olive oil production, the amount of wastes is growing respectively. Olive oil mill waste water (OMWW) is the liquid byproduct in the so-called "three phase" technological process. Features of OMWW include the high content of fatty aliphatic components and polyphenols and their often-considered toxicity. One way of OMWW disposal is the land spreading, e.g., in olive orchards. The land application of OMWW (either controlled or not) is supposed to affect the multiple soil properties, including hydrophobicity and the potential of soils to interact with pesticides. Therefore, there is both basic and applied interest in elucidating the interactions between organic compounds and soils affected by OMWW. However, little is known about the impact of OMWW - soil interactions on sorption of organic compounds, and specifically, on sorption of agrochemicals. This paper reports an experimental study of sorption interactions of a series of organic compounds including widely used herbicides such as diuron and simazine, in a range of soils that were affected by OMWW (i) historically or (ii) in the controlled land disposal experiments. It is demonstrated that there is a distinct increase in apparent sorption of organic chemicals in soils affected by OMWW. In selected systems, this increase may be explained by increase in SOM content. However, the SOM quality places a role: the rise in organic compound - soil interactions may both exceed the SOM

  19. Ubiquitin and proteasomes in transcription.

    Science.gov (United States)

    Geng, Fuqiang; Wenzel, Sabine; Tansey, William P

    2012-01-01

    Regulation of gene transcription is vitally important for the maintenance of normal cellular homeostasis. Failure to correctly regulate gene expression, or to deal with problems that arise during the transcription process, can lead to cellular catastrophe and disease. One of the ways cells cope with the challenges of transcription is by making extensive use of the proteolytic and nonproteolytic activities of the ubiquitin-proteasome system (UPS). Here, we review recent evidence showing deep mechanistic connections between the transcription and ubiquitin-proteasome systems. Our goal is to leave the reader with a sense that just about every step in transcription-from transcription initiation through to export of mRNA from the nucleus-is influenced by the UPS and that all major arms of the system--from the first step in ubiquitin (Ub) conjugation through to the proteasome-are recruited into transcriptional processes to provide regulation, directionality, and deconstructive power. PMID:22404630

  20. Can the hydrophilicity of functional monomers affect chemical interaction?

    Science.gov (United States)

    Feitosa, V P; Ogliari, F A; Van Meerbeek, B; Watson, T F; Yoshihara, K; Ogliari, A O; Sinhoreti, M A; Correr, A B; Cama, G; Sauro, S

    2014-02-01

    The number of carbon atoms and/or ester/polyether groups in spacer chains may influence the interaction of functional monomers with calcium and dentin. The present study assessed the chemical interaction and bond strength of 5 standard-synthesized phosphoric-acid ester functional monomers with different spacer chain characteristics, by atomic absorption spectroscopy (AAS), ATR-FTIR, thin-film x-ray diffraction (TF-XRD), scanning electron microscopy (SEM), and microtensile bond strength (μTBS). The tested functional monomers were 2-MEP (two-carbon spacer chain), 10-MDP (10-carbon), 12-MDDP (12-carbon), MTEP (more hydrophilic polyether spacer chain), and CAP-P (intermediate hydrophilicity ester spacer). The intensity of monomer-calcium salt formation measured by AAS differed in the order of 12-MDDP=10-MDP>CAP-P>MTEP>2-MEP. FTIR and SEM analyses of monomer-treated dentin surfaces showed resistance to rinsing for all monomer-dentin bonds, except with 2-MEP. TF-XRD confirmed the weaker interaction of 2-MEP. Highest µTBS was observed for 12-MDDP and 10-MDP. A shorter spacer chain (2-MEP) of phosphate functional monomers induced formation of unstable monomer-calcium salts, and lower chemical interaction and dentin bond strength. The presence of ester or ether groups within longer spacer carbon chains (CAP-P and MTEP) may affect the hydrophilicity, μTBS, and also the formation of monomer-calcium salts. PMID:24284259

  1. Characterisation of 20S Proteasome in Tritrichomonas foetus and Its Role during the Cell Cycle and Transformation into Endoflagellar Form.

    Directory of Open Access Journals (Sweden)

    Antonio Pereira-Neves

    Full Text Available Proteasomes are intracellular complexes that control selective protein degradation in organisms ranging from Archaea to higher eukaryotes. These structures have multiple proteolytic activities that are required for cell differentiation, replication and maintaining cellular homeostasis. Here, we document the presence of the 20S proteasome in the protist parasite Tritrichomonas foetus. Complementary techniques, such as a combination of whole genome sequencing technologies, bioinformatics algorithms, cell fractionation and biochemistry and microscopy approaches were used to characterise the 20S proteasome of T. foetus. The 14 homologues of the typical eukaryotic proteasome subunits were identified in the T. foetus genome. Alignment analyses showed that the main regulatory and catalytic domains of the proteasome were conserved in the predicted amino acid sequences from T. foetus-proteasome subunits. Immunofluorescence assays using an anti-proteasome antibody revealed a labelling distributed throughout the cytosol as punctate cytoplasmic structures and in the perinuclear region. Electron microscopy of a T. foetus-proteasome-enriched fraction confirmed the presence of particles that resembled the typical eukaryotic 20S proteasome. Fluorogenic assays using specific peptidyl substrates detected presence of the three typical peptidase activities of eukaryotic proteasomes in T. foetus. As expected, these peptidase activities were inhibited by lactacystin, a well-known specific proteasome inhibitor, and were not affected by inhibitors of serine or cysteine proteases. During the transformation of T. foetus to endoflagellar form (EFF, also known as pseudocyst, we observed correlations between the EFF formation rates, increases in the proteasome activities and reduced levels of ubiquitin-protein conjugates. The growth, cell cycle and EFF transformation of T. foetus were inhibited after treatment with lactacystin in a dose-dependent manner. Lactacystin

  2. Epigenetics of proteasome inhibition in the liver of rats fed ethanol chronically

    Institute of Scientific and Technical Information of China (English)

    Joan Oliva; Jennifer Dedes; Jun Li; Samuel W French; Fawzia Bardag-Gorce

    2009-01-01

    AIM: To examine the effects of ethanol-induced proteasome inhibition, and the effects of proteasome inhibition in the regulation of epigenetic mechanisms. METHODS: Rats were fed ethanol for 1 mo using the Tsukamoto-French model and were compared to rats given the proteasome inhibitor PS-341 (Bortezomib, Velcade.) by intraperitoneal injection. Microarray analysis and real time PCR were performed and proteasome activity assays and Western blot analysis were performed using isolated nuclei. RESULTS: Chronic ethanol feeding caused a significant inhibition of the ubiquitin proteasome pathway in the nucleus, which led to changes in the turnover of transcriptional factors, histone-modifying enzymes, and, therefore, affected epigenetic mechanisms. Chronic ethanol feeding was related to an increase in histone acetylation, and it is hypothesized that the proteasome proteolytic activity regulated histone modifications by controlling the stability of histone modifying enzymes, and, therefore, regulated the chromatin structure, allowing easy access to chromatin by RNA polymerase, and, thus, proper gene expression. Proteasome inhibition by PS-341 increased histone acetylation similar to chronic ethanol feeding. In addition, proteasome inhibition caused dramatic changes in hepatic remethylation reactions as there was a significant decrease in the enzymes responsible for the regeneration of S-adenosylmethionine, and, in particular, a significant decrease in the betainehomocysteine methyltransferase enzyme. This suggested that hypomethylation was associated with proteasome inhibition, as indicated by the decrease in histone methylation. CONCLUSION: The role of proteasome inhibition in regulating epigenetic mechanisms, and its link to liver injury in alcoholic liver disease, is thus a promising approach to study liver injury due to chronic ethanol consumption.

  3. Tumor cells with low proteasome subunit expression predict overall survival in head and neck cancer patients

    International Nuclear Information System (INIS)

    Experimental and clinical data suggest that solid cancers contain treatment-resistant cancer stem cells that will impair treatment efficacy. The objective of this study was to investigate if head and neck squamous cell carcinoma (HNSCC) also contain cancer stem cells that can be identified by low 26S proteasome activity and if their presence correlates to clinical outcome. Human HNSCC cells, engineered to report lack of proteasome activity based on accumulation of a fluorescent fusion protein, were separated based on high (ZsGreen-cODCneg) or low (ZsGreen-cODCpos) proteasome activity. Self-renewal capacity, tumorigenicity and radioresistance were assessed. Proteasome subunit expression was analyzed in tissue microarrays and correlated to survival and locoregional cancer control of 174 patients with HNSCC. HNSCC cells with low proteasome activity showed a significantly higher self-renewal capacity and increased tumorigenicity. Irradiation enriched for ZsGreen-cODCpos cells. The survival probability of 82 patients treated with definitive radio- or chemo-radiotherapy exhibiting weak, intermediate, or strong proteasome subunit expression were 21.2, 28.8 and 43.8 months (p = 0.05), respectively. Locoregional cancer control was comparably affected. Subpopulations of HNSCC display stem cell features that affect patients’ tumor control and survival. Evaluating cancer tissue for expression of the proteasome subunit PSMD1 may help identify patients at risk for relapse

  4. Factors affecting interaction of radiocesium with freshwater solids Pt. 2

    International Nuclear Information System (INIS)

    The paper aims at the analysis of principal factors affecting the interaction of radiocesium with freshwater solids, important for the migration of radiocesium in rivers. Uptake and release of radiocesium by bottom sediment and suspended solids from a small stream were studied as a function of contact time during the uptake and release, of concentration of the solid phase and of temperature, using laboratory model experiments. Kinetics of the uptake were found to be significantly affected by temperature and concentration of the solid phase. The kinetics and the concentration effect can be quantitatively described using kinetic model of two parallel or consecutive reactions. Kinetic parameters for the model were determined. Distribution coefficient Kd is independent of sediment concentration in the range of 20-70mg·dm-3 but passes through a maximum at higher concentration values. Release of radiocesium absorbed on the freshwater solids was observed. The amount released decreased with increasing contact time of radiocesium with solid phase. Quantitative evaluation of the release revealed partial irreversibility of radiocesium uptake on the solids studied. Results obtained are compared with literature data and conclusions are drawn on the importance of the factors studied for modeling of radiocesium migration in rivers. (author) 40 refs.; 7 figs.; 6 tabs

  5. What Makes Sports Fans Interactive? Identifying Factors Affecting Chat Interactions in Online Sports Viewing.

    Directory of Open Access Journals (Sweden)

    Minsam Ko

    Full Text Available Sports fans are able to watch games from many locations using TV services while interacting with other fans online. In this paper, we identify the factors that affect sports viewers' online interactions. Using a large-scale dataset of more than 25 million chat messages from a popular social TV site for baseball, we extract various game-related factors, and investigate the relationships between these factors and fans' interactions using a series of multiple regression analyses. As a result, we identify several factors that are significantly related to viewer interactions. In addition, we determine that the influence of these factors varies according to the user group; i.e., active vs. less active users, and loyal vs. non-loyal users.

  6. Proteasomal degradation of the metabotropic glutamate receptor 1α is mediated by Homer-3 via the proteasomal S8 ATPase: Signal transduction and synaptic transmission.

    Science.gov (United States)

    Rezvani, Khosrow; Baalman, Kelli; Teng, Yanfen; Mee, Maureen P; Dawson, Simon P; Wang, Hongmin; De Biasi, Mariella; Mayer, R John

    2012-07-01

    The metabotropic glutamate receptors (mGluRs) fine-tune the efficacy of synaptic transmission. This unique feature makes mGluRs potential targets for the treatment of various CNS disorders. There is ample evidence to show that the ubiquitin proteasome system mediates changes in synaptic strength leading to multiple forms of synaptic plasticity. The present study describes a novel interaction between post-synaptic adaptors, long Homer-3 proteins, and one of the 26S proteasome regulatory subunits, the S8 ATPase, that influences the degradation of the metabotropic glutamate receptor 1α (mGluR1α). We have shown that the two human long Homer-3 proteins specifically interact with human proteasomal S8 ATPase. We identified that mGluR1α and long Homer-3s immunoprecipitate with the 26S proteasome both in vitro and in vivo. We further found that the mGluR1α receptor can be ubiquitinated and degraded by the 26S proteasome and that Homer-3A facilitates this process. Furthermore, the siRNA mediated silencing of Homer-3 led to increased levels of total and plasma membrane-associated mGluR1α receptors. These results suggest that long Homer-3 proteins control the degradation of mGluR1α receptors by shuttling ubiquitinated mGluR-1α receptors to the 26S proteasome via the S8 ATPase which may modulate synaptic transmission.

  7. 26 S proteasomes function as stable entities

    DEFF Research Database (Denmark)

    Hendil, Klavs B; Hartmann-Petersen, Rasmus; Tanaka, Keiji

    2002-01-01

    Most proteins in eukaryotic cells are degraded by 26-S proteasomes, usually after being conjugated to ubiquitin. In the absence of ATP, 26-S proteasomes fall apart into their two sub-complexes, 20-S proteasomes and PA700, which reassemble upon addition of ATP. Conceivably, 26-S proteasomes...... dissociate and reassemble during initiation of protein degradation in a ternary complex with the substrate, as in the dissociation-reassembly cycles found for ribosomes and the chaperonin GroEL/GroES. Here we followed disassembly and assembly of 26-S proteasomes in cell extracts as the exchange of PA700...... subunits between mouse and human 26-S proteasomes. Compared to the rate of proteolysis in the same extract, the disassembly-reassembly cycle was much too slow to present an obligatory step in a degradation cycle. It has been suggested that subunit S5a (Mcb1, Rpn10), which binds poly-ubiquitin substrates...

  8. The proteasomal and apoptotic phenotype determine bortezomib sensitivity of non-small cell lung cancer cells

    Directory of Open Access Journals (Sweden)

    Chęcińska Agnieszka

    2007-11-01

    Full Text Available Abstract Bortezomib is a novel anti-cancer agent which has shown promising activity in non-small lung cancer (NSCLC patients. However, only a subset of patients respond to this treatment. We show that NSCLC cell lines are differentially sensitive to bortezomib, IC50 values ranging from 5 to 83 nM. The apoptosis-inducing potential of bortezomib in NSCLC cells was found to be dependent not only on the apoptotic phenotype but also on the proteasomal phenotype of individual cell lines. Upon effective proteasome inhibition, H460 cells were more susceptible to apoptosis induction by bortezomib than SW1573 cells, indicating a different apoptotic phenotype. However, exposure to a low dose of bortezomib did only result in SW1573 cells, and not in H460 cells, in inhibition of proteasome activity and subsequent apoptosis. This suggests a different proteasomal phenotype as well. Additionally, overexpression of anti-apoptotic protein Bcl-2 in H460 cells did not affect the proteasomal phenotype of H460 cells but did result in decreased bortezomib-induced apoptosis. In conclusion, successful proteasome-inhibitor based treatment strategies in NSCLC face the challenge of having to overcome apoptosis resistance as well as proteasomal resistance of individual lung cancer cells. Further studies in NSCLC are warranted to elucidate underlying mechanisms.

  9. Modeling proteasome dynamics in Parkinson's disease.

    Science.gov (United States)

    Sneppen, Kim; Lizana, Ludvig; Jensen, Mogens H; Pigolotti, Simone; Otzen, Daniel

    2009-01-01

    In Parkinson's disease (PD), there is evidence that alpha-synuclein (alphaSN) aggregation is coupled to dysfunctional or overburdened protein quality control systems, in particular the ubiquitin-proteasome system. Here, we develop a simple dynamical model for the on-going conflict between alphaSN aggregation and the maintenance of a functional proteasome in the healthy cell, based on the premise that proteasomal activity can be titrated out by mature alphaSN fibrils and their protofilament precursors. In the presence of excess proteasomes the cell easily maintains homeostasis. However, when the ratio between the available proteasome and the alphaSN protofilaments is reduced below a threshold level, we predict a collapse of homeostasis and onset of oscillations in the proteasome concentration. Depleted proteasome opens for accumulation of oligomers. Our analysis suggests that the onset of PD is associated with a proteasome population that becomes occupied in periodic degradation of aggregates. This behavior is found to be the general state of a proteasome/chaperone system under pressure, and suggests new interpretations of other diseases where protein aggregation could stress elements of the protein quality control system. PMID:19411740

  10. Proteasome- and Ethanol-Dependent Regulation of HCV-Infection Pathogenesis

    Directory of Open Access Journals (Sweden)

    Natalia A. Osna

    2014-09-01

    Full Text Available This paper reviews the role of the catabolism of HCV and signaling proteins in HCV protection and the involvement of ethanol in HCV-proteasome interactions. HCV specifically infects hepatocytes, and intracellularly expressed HCV proteins generate oxidative stress, which is further exacerbated by heavy drinking. The proteasome is the principal proteolytic system in cells, and its activity is sensitive to the level of cellular oxidative stress. Not only host proteins, but some HCV proteins are degraded by the proteasome, which, in turn, controls HCV propagation and is crucial for the elimination of the virus. Ubiquitylation of HCV proteins usually leads to the prevention of HCV propagation, while accumulation of undegraded viral proteins in the nuclear compartment exacerbates infection pathogenesis. Proteasome activity also regulates both innate and adaptive immunity in HCV-infected cells. In addition, the proteasome/immunoproteasome is activated by interferons, which also induce “early” and “late” interferon-sensitive genes (ISGs with anti-viral properties. Cleaving viral proteins to peptides in professional immune antigen presenting cells and infected (“target” hepatocytes that express the MHC class I-antigenic peptide complex, the proteasome regulates the clearance of infected hepatocytes by the immune system. Alcohol exposure prevents peptide cleavage by generating metabolites that impair proteasome activity, thereby providing escape mechanisms that interfere with efficient viral clearance to promote the persistence of HCV-infection.

  11. Affective and Cognitive Information Behavior: Interaction Effects in Internet Use

    OpenAIRE

    Nahl, Diane

    2005-01-01

    The presence and influence of affective variables in information behavior was studied. Affective load (AL), a compound variable consisting of uncertainty and technophobia measures, was found to be present in a variety of simple and complex information tasks integrated into upper-division, disciplinary coursework. Affective load was higher in those who reported low values of affective coping skills and who had either high or low cognitive assessment scores. Affective coping skills (ACS) consi...

  12. Interactions of neurons with topographic nano cues affect branching morphology mimicking neuron-neuron interactions.

    Science.gov (United States)

    Baranes, Koby; Kollmar, Davida; Chejanovsky, Nathan; Sharoni, Amos; Shefi, Orit

    2012-08-01

    We study the effect of topographic nano-cues on neuronal growth-morphology using invertebrate neurons in culture. We use photolithography to fabricate substrates with repeatable line-pattern ridges of nano-scale heights of 10-150 nm. We plate leech neurons atop the patterned-substrates and compare their growth pattern to neurons plated atop non-patterned substrates. The model system allows us the analysis of single neurite-single ridge interactions. The use of high resolution electron microscopy reveals small filopodia processes that attach to the line-pattern ridges. These fine processes, that cannot be detected in light microscopy, add anchoring sites onto the side of the ridges, thus additional physical support. These interactions of the neuronal process dominantly affect the neuronal growth direction. We analyze the response of the entire neuronal branching tree to the patterned substrates and find significant effect on the growth patterns compared to non-patterned substrates. Moreover, interactions with the nano-cues trigger a growth strategy similarly to interactions with other neuronal cells, as reflected in their morphometric parameters. The number of branches and the number of neurites originating from the soma decrease following the interaction demonstrating a tendency to a more simplified neuronal branching tree. The effect of the nano-cues on the neuronal function deserves further investigation and will strengthen our understanding of the interplay between function and form.

  13. Interaction Between Optical and Neural Factors Affecting Visual Performance

    Science.gov (United States)

    Sabesan, Ramkumar

    The human eye suffers from higher order aberrations, in addition to conventional spherical and cylindrical refractive errors. Advanced optical techniques have been devised to correct them in order to achieve superior retinal image quality. However, vision is not completely defined by the optical quality of the eye, but also depends on how the image quality is processed by the neural system. In particular, how neural processing is affected by the past visual experience with optical blur has remained largely unexplored. The objective of this thesis was to investigate the interaction of optical and neural factors affecting vision. To achieve this goal, pathological keratoconic eyes were chosen as the ideal population to study since they are severely afflicted by degraded retinal image quality due to higher order aberrations and their neural system has been exposed to that habitually for a long period of time. Firstly, we have developed advanced customized ophthalmic lenses for correcting the higher order aberration of keratoconic eyes and demonstrated their feasibility in providing substantial visual benefit over conventional corrective methodologies. However, the achieved visual benefit was significantly smaller than that predicted optically. To better understand this, the second goal of the thesis was set to investigate if the neural system optimizes its underlying mechanisms in response to the long-term visual experience with large magnitudes of higher order aberrations. This study was facilitated by a large-stroke adaptive optics vision simulator, enabling us to access the neural factors in the visual system by manipulating the limit imposed by the optics of the eye. Using this instrument, we have performed a series of experiments to establish that habitual exposure to optical blur leads to an alteration in neural processing thereby alleviating the visual impact of degraded retinal image quality, referred to as neural compensation. However, it was also found that

  14. The ubiquitin proteasome system and efficacy of proteasome inhibitors in diseases.

    Science.gov (United States)

    Chitra, Selvarajan; Nalini, Ganesan; Rajasekhar, Gopalakrishnan

    2012-06-01

    In eukaryotes the ubiquitin proteasome pathway plays an important role in cellular homeostasis and also it exerts a critical role in regulating a wide variety of cellular pathways, including cell growth and proliferation, apoptosis, DNA repair, transcription and immune response. Defects in these pathways have been implicated in a number of human pathologies. Inhibition of the ubiquitin proteasome pathway by proteasome inhibitors may be a rational therapeutic approach for various diseases, such as cancer and inflammatory diseases. Many of the critical cytokine and chemokine mediators of the progression of rheumatoid arthritis are regulated by nuclear factor kappa B (NF-κB). In peptidoglycan/polysaccharide-induced polyarthritis, proteasome inhibitors limit the overall inflammation, reduce NF-κB activation, decrease cellular adhesion molecule expression, inhibit nitric oxide synthase, attenuate circulating levels of proinflammatory cytokine interleukin-6 and reduce the arthritis index and swelling in the joints of the animals. Since proteasome inhibitors exhibit anti-inflammatory and anti proliferative effects, diseases characterized by both of these processes such as rheumatoid arthritis might also represent clinical opportunities for such drugs. The regulation of the proteasomal complex by proteasome inhibitors also has implications and potential benefits for the treatment of rheumatoid arthritis. This review summarizes the ubiquitin proteasome pathway, the structure of 26S proteasomes and types of proteasome inhibitors, with their actions, and clinical applications of proteasome inhibitors in various diseases. PMID:22709487

  15. Structural basis for proteasome formation controlled by an assembly chaperone nas2.

    Science.gov (United States)

    Satoh, Tadashi; Saeki, Yasushi; Hiromoto, Takeshi; Wang, Ying-Hui; Uekusa, Yoshinori; Yagi, Hirokazu; Yoshihara, Hidehito; Yagi-Utsumi, Maho; Mizushima, Tsunehiro; Tanaka, Keiji; Kato, Koichi

    2014-05-01

    Proteasome formation does not occur due to spontaneous self-organization but results from a highly ordered process assisted by several assembly chaperones. The assembly of the proteasome ATPase subunits is assisted by four client-specific chaperones, of which three have been structurally resolved. Here, we provide the structural basis for the working mechanisms of the last, hereto structurally uncharacterized assembly chaperone, Nas2. We revealed that Nas2 binds to the Rpt5 subunit in a bivalent mode: the N-terminal helical domain of Nas2 masks the Rpt1-interacting surface of Rpt5, whereas its C-terminal PDZ domain caps the C-terminal proteasome-activating motif. Thus, Nas2 operates as a proteasome activation blocker, offering a checkpoint during the formation of the 19S ATPase prior to its docking onto the proteolytic 20S core particle. PMID:24685148

  16. Divergent tissue and sex effects of rapamycin on the proteasome-chaperone network of old mice

    Directory of Open Access Journals (Sweden)

    Karl Andrew Rodriguez

    2014-11-01

    Full Text Available Rapamycin, an allosteric inhibitor of the mTOR kinase, increases longevity in mice in a sex-specific manner. In contrast to the widely accepted theory that a loss of proteasome activity is detrimental to both life- and healthspan, biochemical studies in vitro reveal that rapamycin inhibits 20S proteasome peptidase activity. We tested if this unexpected finding is also evident after chronic rapamycin treatment in vivo by measuring peptidase activities for both the 26S and 20S proteasome in liver, fat, and brain tissues of old, male and female mice fed encapsulated chow containing 2.24mg/kg (14 ppm rapamycin for 6 months. Further we assessed if rapamycin altered expression of the chaperone proteins known to interact with the proteasome-mediated degradation system (PMDS, heat shock factor 1 (HSF1, and the levels of key mTOR pathway proteins. Rapamycin had little effect on liver proteasome activity in either gender, but increased proteasome activity in female brain lysates and lowered its activity in female fat tissue. Rapamycin-induced changes in molecular chaperone levels were also more substantial in tissues from female animals. Furthermore, mTOR pathway proteins showed more significant changes in female tissues compared to those from males. These data show collectively that there are divergent tissue and sex effects of rapamycin on the proteasome-chaperone network and that these may be linked to the disparate effects of rapamycin on males and females. Further our findings suggest that rapamycin induces indirect regulation of the PMDS/heat-shock response through its modulation of the mTOR pathway rather than via direct interactions between rapamycin and the proteasome.

  17. The possible role of the ubiquitin proteasome system in the development of atherosclerosis in diabetes

    Directory of Open Access Journals (Sweden)

    sasso Ferdinando

    2007-10-01

    Full Text Available Abstract We have reviewed the impact of the ubiquitin proteasome system (UPS on atherosclerosis progression of diabetic patients. A puzzle of many pieces of evidence suggests that UPS, in addition to its role in the removal of damaged proteins, is involved in a number of biological processes including inflammation, proliferation and apoptosis, all of which constitute important characteristics of atherosclerosis. From what can be gathered from the very few studies on the UPS in diabetic cardiovascular diseases published so far, the system seems to be functionally active to a different extent in the initiation, progression, and complication stage of atherosclerosis in the diabetic people. Further evidence for this theory, however, has to be given, for instance by specifically targeted antagonism of the UPS. Nonetheless, this hypothesis may help us understand why diverse therapeutic interventions, which have in common the ability to reduce ubiquitin-proteasome activity, can impede or delay the onset of diabetes and cardiovascular diseases (CVD. People with type 2 diabetes are disproportionately affected by CVD, compared with those without diabetes 1. The prevalence, incidence, and mortality from all forms of CVD (myocardial infarction, cerebro-vascular disease and congestive heart failure are strikingly increased in persons with diabetes compared with those withoutdiabetes 2. Furthermore, diabetic patients have not benefited by the advances in the management of obesity, dyslipidemia, and hypertension that have resulted in a decrease in mortality for coronary heart disease (CHD patients without diabetes 3. Nevertheless, these risk factors do not fully explain the excess risk for CHD associated with diabetes 45. Thus, the determinants of progression of atherosclerosis in persons with diabetes must be elucidated. Beyond the major risk factors, several studies have demonstrated that such factors, strictly related to diabetes, as insulin

  18. Toward an Integrated Structural Model of the 26S Proteasome*

    Science.gov (United States)

    Förster, Friedrich; Lasker, Keren; Nickell, Stephan; Sali, Andrej; Baumeister, Wolfgang

    2010-01-01

    The 26S proteasome is the end point of the ubiquitin-proteasome pathway and degrades ubiquitylated substrates. It is composed of the 20S core particle (CP), where degradation occurs, and the 19S regulatory particle (RP), which ensures substrate specificity of degradation. Whereas the CP is resolved to atomic resolution, the architecture of the RP is largely unknown. We provide a comprehensive analysis of the current structural knowledge on the RP, including structures of the RP subunits, physical protein-protein interactions, and cryoelectron microscopy data. These data allowed us to compute an atomic model for the CP-AAA-ATPase subcomplex. In addition to this atomic model, further subunits can be mapped approximately, which lets us hypothesize on the substrate path during its degradation. PMID:20467039

  19. Toward an integrated structural model of the 26S proteasome.

    Science.gov (United States)

    Förster, Friedrich; Lasker, Keren; Nickell, Stephan; Sali, Andrej; Baumeister, Wolfgang

    2010-08-01

    The 26S proteasome is the end point of the ubiquitin-proteasome pathway and degrades ubiquitylated substrates. It is composed of the 20S core particle (CP), where degradation occurs, and the 19S regulatory particle (RP), which ensures substrate specificity of degradation. Whereas the CP is resolved to atomic resolution, the architecture of the RP is largely unknown. We provide a comprehensive analysis of the current structural knowledge on the RP, including structures of the RP subunits, physical protein-protein interactions, and cryoelectron microscopy data. These data allowed us to compute an atomic model for the CP-AAA-ATPase subcomplex. In addition to this atomic model, further subunits can be mapped approximately, which lets us hypothesize on the substrate path during its degradation.

  20. Differential roles of the COOH termini of AAA subunits of PA700 (19 S regulator) in asymmetric assembly and activation of the 26 S proteasome.

    Science.gov (United States)

    Gillette, Thomas G; Kumar, Brajesh; Thompson, David; Slaughter, Clive A; DeMartino, George N

    2008-11-14

    The 26 S proteasome is an energy-dependent protease that degrades proteins modified with polyubiquitin chains. It is assembled from two multi-protein subcomplexes: a protease (20 S proteasome) and an ATPase regulatory complex (PA700 or 19 S regulatory particle) that contains six different AAA family subunits (Rpt1 to -6). Here we show that binding of PA700 to the 20 S proteasome is mediated by the COOH termini of two (Rpt2 and Rpt5) of the six Rpt subunits that constitute the interaction surface between the subcomplexes. COOH-terminal peptides of either Rpt2 or Rpt5 bind to the 20 S proteasome and activate hydrolysis of short peptide substrates. Simultaneous binding of both COOH-terminal peptides had additive effects on peptide substrate hydrolysis, suggesting that they bind to distinct sites on the proteasome. In contrast, only the Rpt5 peptide activated hydrolysis of protein substrates. Nevertheless, the COOH-terminal peptide of Rpt2 greatly enhanced this effect, suggesting that proteasome activation is a multistate process. Rpt2 and Rpt5 COOH-terminal peptides cross-linked to different but specific subunits of the 20 S proteasome. These results reveal critical roles of COOH termini of Rpt subunits of PA700 in the assembly and activation of eukaryotic 26 S proteasome. Moreover, they support a model in which Rpt subunits bind to dedicated sites on the proteasome and play specific, nonequivalent roles in the asymmetric assembly and activation of the 26 S proteasome.

  1. Mobile Education: Towards Affective Bi-modal Interaction for Adaptivity

    Directory of Open Access Journals (Sweden)

    Efthymios Alepis

    2009-04-01

    Full Text Available One important field where mobile technology can make significant contributions is education. However one criticism in mobile education is that students receive impersonal teaching. Affective computing may give a solution to this problem. In this paper we describe an affective bi-modal educational system for mobile devices. In our research we describe a novel approach of combining information from two modalities namely the keyboard and the microphone through a multi-criteria decision making theory.

  2. Use of proteasome inhibitors in anticancer therapy

    Directory of Open Access Journals (Sweden)

    Sara M. Schmitt

    2011-10-01

    Full Text Available The importance of the ubiquitin-proteasome pathway to cellular function has brought it to the forefront in the search for new anticancer therapies. The ubiquitin-proteasome pathway has proven promising in targeting various human cancers. The approval of the proteasome inhibitor bortezomib for clinical treatment of relapsed/refractory multiple myeloma and mantle cell lymphoma has validated the ubiquitin-proteasome as a rational target. Bortezomib has shown positive results in clinical use but some toxicity and side effects, as well as resistance, have been observed, indicating that further development of novel, less toxic drugs is necessary. Because less toxic drugs are necessary and drug development can be expensive and time-consuming, using existing drugs that can target the ubiquitin-proteasome pathway in new applications, such as cancer therapy, may be effective in expediting the regulatory process and bringing new drugs to the clinic. Toward this goal, previously approved drugs, such as disulfiram, as well as natural compounds found in common foods, such as green tea polyphenol (--EGCG and the flavonoid apigenin, have been investigated for their possible proteasome inhibitory and cell death inducing abilities. These compounds proved quite promising in preclinical studies and have now moved into clinical trials, with preliminary results that are encouraging. In addition to targeting the catalytic activity of the proteasome pathway, upstream regulators, such as the 19S regulatory cap, as well as E1, E2, and E3, are now being investigated as potential drug targets. This review outlines the development of novel proteasome inhibitors from preclinical to clinical studies, highlighting their abilities to inhibit the tumor proteasome and induce apoptosis in several human cancers.

  3. Defective Proteasome Delivery of Polyubiquitinated Proteins by Ubiquilin-2 Proteins Containing ALS Mutations.

    Directory of Open Access Journals (Sweden)

    Lydia Chang

    Full Text Available Ubiquilin proteins facilitate delivery of ubiquitinated proteins to the proteasome for degradation. Interest in the proteins has been heightened by the discovery that gene mutations in UBQLN2 cause dominant inheritance of amyotrophic lateral sclerosis (ALS. However, the mechanisms by which the mutations cause ALS are not known. Here we report on the underlying defect of ubiquilin-2 proteins containing ALS-linked mutations in affecting proteasome-mediated degradation. We found that overexpression of ubiquilin-2 proteins containing any one of five different ALS mutations slow degradation of Myc, a prototypic proteasome substrate. Examination of coprecipitating proteins indicated that the mutant proteins are generally capable of binding polyubiquitinated proteins, but defective in binding the proteasome. GST-pulldown studies revealed that many of the mutants bind weaker to the S5a subunit of the proteasome, compared with wild type (WT ubiquilin-2 protein. The results suggest the mutant proteins are unable to deliver their captured cargo to the proteasome for degradation, which presumably leads to toxicity. Quantification of cell death is consistent with this idea. Measurement of protein turnover further indicated the mutant proteins have longer half-lives than WT ubiquilin-2. Our studies provide novel insight into the mechanism by which ALS-linked mutations in UBQLN2 interfere with protein degradation.

  4. Biochemical and Biophysical Characterization of Recombinant Yeast Proteasome Maturation Factor UMP1

    Directory of Open Access Journals (Sweden)

    Bebiana Sá-Moura

    2013-04-01

    Full Text Available Protein degradation is essential for maintaining cellular homeostasis. The proteasome is the central enzyme responsible for non-lysosomal protein degradation in eukaryotic cells. Although proteasome assembly is not yet completely understood, a number of cofactors required for proper assembly and maturation have been identified. Ump1 is a short-lived maturation factor required for the efficient biogenesis of the 20S proteasome. Upon the association of the two precursor complexes, Ump1 is encased and is rapidly degraded after the proteolytic sites in the interior of the nascent proteasome are activated. In order to further understand the mechanisms behind proteasomal maturation, we expressed and purified yeast Ump1 in E. coli for biophysical and structural analysis.We show that recombinant Ump1 is purified as a mixture of different oligomeric species and that oligomerization is mediated by intermolecular disulfide bond formation involving the only cysteine residue present in the protein. Furthermore, a combination of bioinformatics tools, biochemical and structural analysis revealed that Ump1 shows characteristics of an intrinsically disordered protein, which might become structured only upon interaction with the proteasome subunits.

  5. Regulators of the proteasome pathway, Uch37 and Rpn13, play distinct roles in mouse development.

    Directory of Open Access Journals (Sweden)

    Amin Al-Shami

    Full Text Available Rpn13 is a novel mammalian proteasomal receptor that has recently been identified as an amplification target in ovarian cancer. It can interact with ubiquitin and activate the deubiquitinating enzyme Uch37 at the 26S proteasome. Since neither Rpn13 nor Uch37 is an integral proteasomal subunit, we explored whether either protein is essential for mammalian development and survival. Deletion of Uch37 resulted in prenatal lethality in mice associated with severe defect in embryonic brain development. In contrast, the majority of Rpn13-deficient mice survived to adulthood, although they were smaller at birth and fewer in number than wild-type littermates. Absence of Rpn13 produced tissue-specific effects on proteasomal function: increased proteasome activity in adrenal gland and lymphoid organs, and decreased activity in testes and brain. Adult Rpn13(-/- mice reached normal body weight but had increased body fat content and were infertile due to defective gametogenesis. Additionally, Rpn13(-/- mice showed increased T-cell numbers, resembling growth hormone-mediated effects. Indeed, serum growth hormone and follicular stimulating hormone levels were significantly increased in Rpn13(-/- mice, while growth hormone receptor expression was reduced in the testes. In conclusion, this is the first report characterizing the physiological roles of Uch37 and Rpn13 in murine development and implicating a non-ATPase proteasomal protein, Rpn13, in the process of gametogenesis.

  6. Regulation of Sperm Capacitation by the 26S Proteasome: An Emerging New Paradigm in Spermatology.

    Science.gov (United States)

    Kerns, Karl; Morales, Patricio; Sutovsky, Peter

    2016-05-01

    The ubiquitin proteasome system (UPS) participates in many biological processes ranging from cell cycle and antigen processing to cellular defense and signaling. Work of the last decade has made it evident that the UPS is involved in many sperm-related processes leading up to and as part of fertilization. The current knowledge of UPS involvement and changes during sperm capacitation are reviewed together with a list of known proteasome-associated sperm proteins and a discussion of the relationships between these proteins and the proteasome. Proteasomal inhibitors such as MG-132 and epoxomicin significantly alter capacitation and prevent acrosome reaction. The 26S proteasome degrades AKAP3, an A-kinase anchoring protein, partially regulating the release of protein-kinase A (PKA), a vital component necessary for the steps leading up to capacitation. Further, changes occur in 20S core subunit localization and abundance throughout capacitation. Proteasome-interacting valosine-containing protein (VCP) undergoes tyrosine phosphorylation; however, its physiological roles in capacitation and fertilization remain unknown. The E1-type ubiquitin-activating enzyme (UBA1) inhibitor PYR-41 also alters acrosomal membrane remodeling during capacitation. Furthermore, after capacitation, the acrosomal proteasomes facilitate the degradation of zona pellucida glycoproteins leading up to fertilization. Methods to modulate the sperm proteasome activity during sperm storage and capacitation may translate to increased reproductive efficiency in livestock animals. Human male infertility diagnostics may benefit from incorporation of research outcomes built upon relationships between UPS and capacitation. Altogether, the studies reviewed here support the involvement of UPS in sperm capacitation and present opportunities for new discoveries. PMID:27053366

  7. Native structure of rat liver immune proteasomes.

    Science.gov (United States)

    Stepanova, A A; Lyupina, Yu V; Sharova, N P; Erokhov, P A

    2016-05-01

    Native structure of active forms of rat liver immune proteasomes has been studied by two-dimensional electrophoresis method modified for analysis of unpurified protein fractions. The developed method allowed revealing the proteasome immune subunits LMP7 and LMP2 in 20S subparticles and in the structures bound to one or two PA28αβ activators, but not to the PA700 activator, which is involved in the hydrolysis of ubiquitinated proteins. The results obtained indicate the participation of the immune proteasomes in delicate regulatory mechanisms based on the production of biologically active peptides and exclude their participation in processes of crude degradation of "rotated" ubiquitinated proteins. PMID:27417720

  8. Identification and Characterisation of a Proteasome -

    DEFF Research Database (Denmark)

    Andersen, Katrine Mølgaard

    domain. A txl1 yeast knockout mutant displays a synthetic growth defect with a cut8 knockout, whereas the txc1 knockout does not. In fission yeast, Cut8 is a nuclear protein that tethers the 26S proteasome to the nuclear membrane. In both wild type cells and in a cut8 null mutant Txl1 co-localises with...... the proteasome at the nuclear rim, whereas Txc1 is distributed throughout the cytoplasm and nucleus. This indicates that Txl1 is closely associated with the 26S proteasome while Txc1 is perhaps only transiently bound to the complex. A slight stabilisation of ubiquitin conjugates was observed upon...

  9. Wash interacts with lamin and affects global nuclear organization

    OpenAIRE

    Verboon, Jeffrey M; Rincon-Arano, Hector; Werwie, Timothy R.; Delrow, Jeffrey J.; Scalzo, David; Nandakumar, Vivek; Groudine, Mark; Parkhurst, Susan M.

    2015-01-01

    The cytoplasmic functions of Wiskott-Aldrich Syndrome family (WAS) proteins are well established and include roles in cytoskeleton reorganization and membrane-cytoskeletal interactions important for membrane/vesicle trafficking, morphogenesis, immune response and signal transduction. Mis-regulation of these proteins is associated with immune deficiency and metastasis [1-4]. Cytoplasmic WAS proteins act as effectors of Rho family GTPases and polymerize branched actin through the Arp2/3 complex...

  10. Woody stem galls interact with foliage to affect community associations.

    Science.gov (United States)

    Cooper, W R; Rieske, L K

    2009-04-01

    Gall wasps (Hymenoptera: Cynipidae) hijack the physiology of their host plant to produce galls that house wasps throughout their immature stages. The gall-maker-host plant interaction is highly evolved, and galls represent an extended phenotype of the gall wasp. We evaluated two-way interactions between stem galls produced by Dryocosmus kuriphilus Yasumatsu on Castanea spp. (Fagales: Fagaceae) and foliage directly attached to galls (gall leaves) using gall leaf excision experiments and herbivore bioassays. Early season gall leaf excision decreased the dry weight per chamber (nutritive index) and thickness of the protective schlerenchyma layer and increased the number of empty chambers and the occurrence and size of exterior fungal lesions. Leaf excision also caused a modestly significant (alpha = 0.1) increase in the incidence of feeding chamber fungi and herbivory by Curculio sayi Gyllenhal (Coleoptera: Curculionidae), and a modest decrease in parasitoids. This study shows that gall leaves are important for stem gall development, quality, and defenses, adding support for the nutrient and enemy hypotheses. We also evaluated the effects of stem galls on the suitability of gall leaves to Lymantria dispar L. (Lepidoptera: Lymantriidae) herbivory to assess the extent of gall defenses in important source leaves. Relative growth rate of L. dispar larvae was greater on gall leaves compared with normal leaves, indicating that, despite their importance, gall leaves may be more suitable to generalist insect herbivores, suggesting limitations to the extended phenotype of the gall wasp. Our results improve our knowledge of host-cynipid interactions, gall source-sink relations, and D. kuriphilus community interactions.

  11. Epistatic Interactions between CREB and CREM Variants in Affective Disorder

    OpenAIRE

    Chiesa, Alberto; Marsano, Agnese; Han, Changsu; Lee, Soo-Jung; Patkar, Ashwin A.; Pae, Chi-Un; Serretti, Alessandro

    2014-01-01

    The aim of the present work is to investigate the existence of epistatic interactions possibly influencing psychotropic agents' response between rs6740584 within Cyclic adenosine monophosphate Response Element Binding (CREB) and rs12775799 within cAMP response element-modulator (CREM) variants in bipolar disorder (BD) and major depressive disorder (MDD). All BD and MDD patients were administered with the Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HAMD) at baseline a...

  12. Identification of interspecies interactions affecting Porphyromonas gingivalis virulence phenotypes

    Directory of Open Access Journals (Sweden)

    Elizabeth L. Tenorio

    2011-10-01

    Full Text Available Background: Periodontitis is recognized as a complex polymicrobial disease, however, the impact of the bacterial interactions among the 700–1,000 different species of the oral microbiota remains poorly understood. We conducted an in vitro screen for oral bacteria that mitigate selected virulence phenotypes of the important periodontal pathogen, Porphyromonas gingivalis. Methods: We isolated and identified oral anaerobic bacteria from subgingival plaque of dental patients. When cocultured with P. gingivalis W83, specific isolates reduced the cytopathogenic effects of P. gingivalis on oral epithelial cells. Results: In an initial screen of 103 subgingival isolates, we identified 19 distinct strains from nine species of bacteria (including Actinomyces naeslundii, Streptococcus oralis, Streptococcus mitis, and Veilonella dispar that protect oral epithelial cells from P. gingivalis-induced cytotoxicity. We found that some of these strains inhibited P. gingivalis growth in plate assays through the production of organic acids, whereas some decreased the gingipain activity of P. gingivalis in coculture or mixing experiments. Conclusion: In summary, we identified 19 strains isolated from human subgingival plaque that interacted with P. gingivalis, resulting in mitigation of its cytotoxicity to oral epithelial cells, inhibition of growth, and/or reduction of gingipain activity. Understanding the mechanisms of interaction between bacteria in the oral microbial community may lead to the development of new probiotic agents and new strategies for interrupting the development of periodontal disease.

  13. Toward affective brain-computer interfaces : exploring the neurophysiology of affect during human media interaction

    NARCIS (Netherlands)

    Mühl, Christian

    2012-01-01

    Affective Brain-Computer Interfaces (aBCI), the sensing of emotions from brain activity, seems a fantasy from the realm of science fiction. But unlike faster-than-light travel or teleportation, aBCI seems almost within reach due to novel sensor technologies, the advancement of neuroscience, and the

  14. Personality interacts with implicit affect to predict performance in analytic versus holistic processing.

    Science.gov (United States)

    Kazén, Miguel; Kuhl, Julius; Quirin, Markus

    2015-06-01

    Both theoretical approaches and empirical evidence suggest that negative affect fosters analytic processing, whereas positive affect fosters holistic processing, but these effects are inconsistent. We aim to show that (a) differences in affect regulation abilities ("action orientation") and (b) implicit more so than self-reported affect assessment need to be considered to advance our understanding of these processes. Forty participants were asked to verify whether a word was correctly or incorrectly spelled to measure analytic processing, as well as to intuitively assess whether sets of three words were coherent (remote associates task) to measure holistic processing. As expected, implicit but not explicit negative affect interacted with low action orientation ("state orientation") to predict higher d' performance in word spelling, whereas implicit but not explicit positive affect interacted with high action orientation to predict higher d' performance in coherence judgments for word triads. Results are interpreted according to personality systems interaction theory. These findings suggest that affect and affect changes should be measured explicitly and implicitly to investigate affect-cognition interactions. Moreover, they suggest that good affect regulators benefit from positive affect for holistic processing, whereas bad affect regulators benefit from negative affect for analytical processing. PMID:24725069

  15. Implication of altered proteasome function in alcoholic liver injury

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The proteasome is a major protein-degrading enzyme,which catalyzes degradation of oxidized and aged proteins, signal transduction factors and cleaves peptides for antigen presentation. Proteasome exists in the equilibrium of 26S and 20S particles. Proteasome function is altered by ethanol metabolism, depending on oxidative stress levels: low oxidative stress induces proteasome activity, while high oxidative stress reduces it. The proposed mechanisms for modulation of proteasome activity are related to oxidative modification of proteasomal proteins with primary and secondary products derived from ethanol oxidation.Decreased proteolysis by the proteasome results in the accumulation of insoluble protein aggregates, which cannot be degraded by proteasome and which further inhibit proteasome function. Mallory bodies, a common signature of alcoholic liver diseases, are formed by liver cells, when proteasome is unable to remove cytokeratins.Proteasome inhibition by ethanol also promotes the accumulation of pro-apoptotic factors in mitochondria of ethanol-metabolizing liver cells that are normally degraded by proteasome. In addition, decreased proteasome function also induces accumulation of the negative regulators of cytokine signaling (Ⅰ-κB and SOCS), thereby blocking cytokine signal transduction.Finally, ethanol-elicited blockade of interferon type 1 and 2 signaling and decreased proteasome function impairs generation of peptides for MHC class Ⅰ-restricted antigen presentation.

  16. Temporal factors affecting somatosensory-auditory interactions in speech processing

    Directory of Open Access Journals (Sweden)

    Takayuki eIto

    2014-11-01

    Full Text Available Speech perception is known to rely on both auditory and visual information. However, sound specific somatosensory input has been shown also to influence speech perceptual processing (Ito et al., 2009. In the present study we addressed further the relationship between somatosensory information and speech perceptual processing by addressing the hypothesis that the temporal relationship between orofacial movement and sound processing contributes to somatosensory-auditory interaction in speech perception. We examined the changes in event-related potentials in response to multisensory synchronous (simultaneous and asynchronous (90 ms lag and lead somatosensory and auditory stimulation compared to individual unisensory auditory and somatosensory stimulation alone. We used a robotic device to apply facial skin somatosensory deformations that were similar in timing and duration to those experienced in speech production. Following synchronous multisensory stimulation the amplitude of the event-related potential was reliably different from the two unisensory potentials. More importantly, the magnitude of the event-related potential difference varied as a function of the relative timing of the somatosensory-auditory stimulation. Event-related activity change due to stimulus timing was seen between 160-220 ms following somatosensory onset, mostly around the parietal area. The results demonstrate a dynamic modulation of somatosensory-auditory convergence and suggest the contribution of somatosensory information for speech processing process is dependent on the specific temporal order of sensory inputs in speech production.

  17. The proteasomes of two marine decapod crustaceans, European lobster (Homarus gammarus) and Edible crab (Cancer pagurus), are differently impaired by heavy metals.

    Science.gov (United States)

    Götze, Sandra; Bose, Aneesh; Sokolova, Inna M; Abele, Doris; Saborowski, Reinhard

    2014-05-01

    The intracellular ubiquitin-proteasome system is a key regulator of cellular processes involved in the controlled degradation of short-living or malfunctioning proteins. Certain diseases and cellular dysfunctions are known to arise from the disruption of proteasome pathways. Trace metals are recognized stressors of the proteasome system in vertebrates and plants, but their effects on the proteasome of invertebrates are not well understood. Since marine invertebrates, and particularly benthic crustaceans, can be exposed to high metal levels, we studied the effects of in vitro exposure to Hg(2+), Zn(2+), Cu(2+), and Cd(2+) on the activities of the proteasome from the claw muscles of lobsters (Homarus gammarus) and crabs (Cancer pagurus). The chymotrypsin like activity of the proteasome of these two species showed different sensitivity to metals. In lobsters the activity was significantly inhibited by all metals to a similar extent. In crabs the activities were severely suppressed only by Hg(2+) and Cu(2+) while Zn(2+) had only a moderate effect and Cd(2+) caused almost no inhibition of the crab proteasome. This indicates that the proteasomes of both species possess structural characteristics that determine different susceptibility to metals. Consequently, the proteasome-mediated protein degradation in crab C. pagurus may be less affected by metal pollution than that of the lobster H. gammarus. PMID:24721378

  18. Affective Interaction with a Virtual Character through an fNIRS Brain-Computer Interface

    OpenAIRE

    Aranyi, Gabor; Pecune, Florian; Charles, Fred; Pelachaud, Catherine; Cavazza, Marc

    2016-01-01

    Affective brain-computer interfaces (BCI) harness Neuroscience knowledge to develop affective interaction from first principles. In this article, we explore affective engagement with a virtual agent through Neurofeedback (NF). We report an experiment where subjects engage with a virtual agent by expressing positive attitudes towards her under a NF paradigm. We use for affective input the asymmetric activity in the dorsolateral prefrontal cortex (DL-PFC), which has been previously found to be ...

  19. Interactions between Artificial Gravity, Affected Physiological Systems, and Nutrition

    Science.gov (United States)

    Heer, Martina; Baecker, Natalie; Zwart, Sara; Smith, Scott M.

    2007-01-01

    Malnutrition, either by insufficient supply of some nutrients or by overfeeding has a profound effect on the health of an organism. Therefore, optimal nutrition is mandatory on Earth (1 g), in microgravity and also when applying artificial gravity to the human system. Immobilization like in microgravity or bed rest also has a profound effect on different physiological systems, like body fluid regulation, the cardiovascular, the musculoskeletal, the immunological system and others. Up to now there is no countermeasure available which is effective to counteract cardiovascular deconditioning (rf. Chapter 5) together with maintenance of the musculoskeletal system in a rather short period of time. Gravity seems therefore to be one of the main stimuli to keep these systems and application of certain duration of artificial gravity per day by centrifugation has often been proposed as a very potential countermeasure against the weakening of the physiological systems. Up to now, neither optimal intensity nor optimal length of application of artificial gravity has been studied sufficiently to recommend a certain, effective and efficient protocol. However, as shown in chapter 5 on cardiovascular system, in chapter 6 on the neuromuscular system and chapter 7 (bone and connective system) artificial gravity has a very high potential to counteract any degradation caused by immobilization. But, nutrient supply -which ideally should match the actual needs- will interact with these changes and therefore has also to be taken into account. It is well known that astronauts beside the Skylab missions- were and are still not optimally nourished during their stay in space (Bourland et al. 2000;Heer et al. 1995;Heer et al. 2000b;Smith et al. 1997;Smith & Lane 1999;Smith et al. 2001;Smith et al. 2005). It has also been described anecdotally that astronauts have lower appetites. One possible explanation could be altered taste and smell sensations during space flight, although in some early

  20. ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

    Science.gov (United States)

    Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

    2013-09-01

    NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis. PMID:23772801

  1. Radiation inhibits proteasomes and increases ubiquitinated proteins

    International Nuclear Information System (INIS)

    Full text: Exposure of cells to ionizing radiation results in accumulation of a number of short lived proteins that mediate cell survival/death, proliferation, repair, and differentiation. Expression of most of these proteins, including p53, mdm2, p21, c-jun, IkB-a, bcl-2, bax, cyclins A, B, E, Cdc25A, DNA-PKcs, and caspase-3 is regulated at the post-transcriptional level through ubiquitin/26S proteasome pathway. Several previous studies have shown that inhibition of proteasome activity by drugs leads to accumulation of ubiquitinated proteins. In this study we show that irradiation can do the same due to its inhibitory effect on 26S, but not 20S, proteasome activity. Two prostate cancer cell lines, murine TRAMP-C1 and human PC3, were used to examine the effect of ionizing radiation on the catalytic activity of the 26S proteasome. Cells were irradiated with different doses ranging from 0.25 to 20 Gy and lysed at different time points after irradiation. Crude extracts of both cell lines showed a rapid 30-50% decrease in chymotryptic activity of the 26S proteasome, as measured by a fluorogenic assay. The same level of inhibition was observed if purified 26S proteasomes were themselves irradiated, indicating that radiation has direct effects on this multicatalytic enzyme complex. Neither direct irradiation of proteasomes or cells had effect on 20S catalytic activity, suggesting that radiation selectively acts on 26S structure. Next, we examined whether this partial inhibition had any effect on ability of 26S proteasome to efficiently remove ubiquitinated proteins. Cells were irradiated with 10Gy and lysed at different time points. Ubiquitinated proteins were precipitated and examined by Western blot. Levels of ubiquitinated conjugates slowly increased over time and peaked at 7h post-irradiation. Accumulation of ubiquitinated conjugates has been shown to lead to formation of protein aggregates which can induce cell death. It has also been shown that monoubiquitination

  2. Proteomics of the 26S proteasome in Spodoptera frugiperda cells infected with the nucleopolyhedrovirus, AcMNPV.

    Science.gov (United States)

    Lyupina, Yulia V; Zatsepina, Olga G; Serebryakova, Marina V; Erokhov, Pavel A; Abaturova, Svetlana B; Kravchuk, Oksana I; Orlova, Olga V; Beljelarskaya, Svetlana N; Lavrov, Andrey I; Sokolova, Olga S; Mikhailov, Victor S

    2016-06-01

    Baculoviruses are large DNA viruses that infect insect species such as Lepidoptera and are used in biotechnology for protein production and in agriculture as insecticides against crop pests. Baculoviruses require activity of host proteasomes for efficient reproduction, but how they control the cellular proteome and interact with the ubiquitin proteasome system (UPS) of infected cells remains unknown. In this report, we analyzed possible changes in the subunit composition of 26S proteasomes of the fall armyworm, Spodoptera frugiperda (Sf9), cells in the course of infection with the Autographa californica multiple nucleopolyhedrovirus (AcMNPV). 26S proteasomes were purified from Sf9 cells by an immune affinity method and subjected to 2D gel electrophoresis followed by MALDI-TOF mass spectrometry and Mascot search in bioinformatics databases. A total of 34 homologues of 26S proteasome subunits of eukaryotic species were identified including 14 subunits of the 20S core particle (7 α and 7 β subunits) and 20 subunits of the 19S regulatory particle (RP). The RP contained homologues of 11 of RPN-type and 6 of RPT-type subunits, 2 deubiquitinating enzymes (UCH-14/UBP6 and UCH-L5/UCH37), and thioredoxin. Similar 2D-gel maps of 26S proteasomes purified from uninfected and AcMNPV-infected cells at 48hpi confirmed the structural integrity of the 26S proteasome in insect cells during baculovirus infection. However, subtle changes in minor forms of some proteasome subunits were detected. A portion of the α5(zeta) cellular pool that presumably was not associated with the proteasome underwent partial proteolysis at a late stage in infection.

  3. Proteomics of the 26S proteasome in Spodoptera frugiperda cells infected with the nucleopolyhedrovirus, AcMNPV.

    Science.gov (United States)

    Lyupina, Yulia V; Zatsepina, Olga G; Serebryakova, Marina V; Erokhov, Pavel A; Abaturova, Svetlana B; Kravchuk, Oksana I; Orlova, Olga V; Beljelarskaya, Svetlana N; Lavrov, Andrey I; Sokolova, Olga S; Mikhailov, Victor S

    2016-06-01

    Baculoviruses are large DNA viruses that infect insect species such as Lepidoptera and are used in biotechnology for protein production and in agriculture as insecticides against crop pests. Baculoviruses require activity of host proteasomes for efficient reproduction, but how they control the cellular proteome and interact with the ubiquitin proteasome system (UPS) of infected cells remains unknown. In this report, we analyzed possible changes in the subunit composition of 26S proteasomes of the fall armyworm, Spodoptera frugiperda (Sf9), cells in the course of infection with the Autographa californica multiple nucleopolyhedrovirus (AcMNPV). 26S proteasomes were purified from Sf9 cells by an immune affinity method and subjected to 2D gel electrophoresis followed by MALDI-TOF mass spectrometry and Mascot search in bioinformatics databases. A total of 34 homologues of 26S proteasome subunits of eukaryotic species were identified including 14 subunits of the 20S core particle (7 α and 7 β subunits) and 20 subunits of the 19S regulatory particle (RP). The RP contained homologues of 11 of RPN-type and 6 of RPT-type subunits, 2 deubiquitinating enzymes (UCH-14/UBP6 and UCH-L5/UCH37), and thioredoxin. Similar 2D-gel maps of 26S proteasomes purified from uninfected and AcMNPV-infected cells at 48hpi confirmed the structural integrity of the 26S proteasome in insect cells during baculovirus infection. However, subtle changes in minor forms of some proteasome subunits were detected. A portion of the α5(zeta) cellular pool that presumably was not associated with the proteasome underwent partial proteolysis at a late stage in infection. PMID:26945516

  4. Elevated CO2 Affects Predator-Prey Interactions through Altered Performance

    OpenAIRE

    Bridie J. M. Allan; Paolo Domenici; McCormick, Mark I.; Sue-Ann Watson; Munday, Philip L.

    2013-01-01

    Recent research has shown that exposure to elevated carbon dioxide (CO2) affects how fishes perceive their environment, affecting behavioral and cognitive processes leading to increased prey mortality. However, it is unclear if increased mortality results from changes in the dynamics of predator-prey interactions or due to prey increasing activity levels. Here we demonstrate that ocean pCO2 projected to occur by 2100 significantly effects the interactions of a predator-prey pair of common ree...

  5. The Dynamic Reactance Interaction - How Vested Interests Affect People's Experience, Behavior, and Cognition in Social Interactions.

    Science.gov (United States)

    Steindl, Christina; Jonas, Eva

    2015-01-01

    In social interactions, individuals may sometimes pursue their own interests at the expense of their interaction partner. Such self-interested behaviors impose a threat to the interaction partner's freedom to act. The current article investigates this threat in the context of interdependence and reactance theory. We explore how vested interests influence reactance process stages of an advisor-client interaction. We aim to explore the interactional process that evolves. In two studies, participants took the perspective of a doctor (advisor) or a patient (client). In both studies we incorporated a vested interest. In Study 1 (N = 82) we found that in response to a vested interest of their interaction partner, patients indicated a stronger experience of reactance, more aggressive behavioral intentions, and more biased cognitions than doctors. A serial multiple mediation revealed that a vested interest engendered mistrust toward the interaction partner and this mistrust led to an emerging reactance process. Study 2 (N = 207) further demonstrated that doctors expressed their reactance in a subtle way: they revealed a classic confirmation bias when searching for additional information on their preliminary decision preference, indicating stronger defense motivation. We discuss how these findings can help us to understand how social interactions develop dynamically. PMID:26640444

  6. Physiological levels of ATP Negatively Regulate Proteasome Function

    OpenAIRE

    Huang, Hongbiao; Zhang, Xiaoyan; Li, Shujue; Liu, Ningning; Lian, Wen; McDowell, Emily; Zhou, Ping; Zhao, Canguo; Guo, Haiping; Zhang, Change; Yang, Changshan; Wen, Guangmei; Dong, Xiaoxian; Lu, Li; Ma, Ningfang

    2010-01-01

    Intracellular protein degradation by the ubiquitin-proteasome system is ATP-dependent and the optimal ATP concentration to activate proteasome function in vitro is ~100 μM. Intracellular ATP levels are generally in the low millimolar range but ATP at a level within this range was shown to inhibit proteasome peptidase activities in vitro. Here we report new evidence that supports a hypothesis that intracellular ATP at the physiological levels bidirectionally regulates 26S proteasome proteolyti...

  7. Transferring substrates to the 26S proteasome

    DEFF Research Database (Denmark)

    Hartmann-Petersen, Rasmus; Seeger, Michael; Gordon, Colin

    2003-01-01

    Ubiquitin-dependent protein degradation is not only involved in the recycling of amino acids from damaged or misfolded proteins but also represents an essential and deftly controlled mechanism for modulating the levels of key regulatory proteins. Chains of ubiquitin conjugated to a substrate...... protein specifically target it for degradation by the 26S proteasome, a huge multi-subunit protein complex found in all eukaryotic cells. Recent reports have clarified some of the molecular mechanisms involved in the transfer of ubiquitinated substrates from the ubiquitination machinery to the proteasome...

  8. Understanding the Role of Interaction from Linguistic, Affective, and Social Perspectives

    Science.gov (United States)

    Xu, Guang

    2010-01-01

    This study was conducted to broaden the scope of studies on interaction. It examined the role of interaction in terms of linguistic, affective, and social aspects. A questionnaire was administered and intensive interviews conducted to reveal the reality of communication between Chinese ESL students and Canadian native English speakers and how…

  9. In Search of the Affective Subject Interacting in the ROODA Virtual Learning Environment

    OpenAIRE

    Longhi, Magalí Teresinha; Behar, Patricia Alejandra; Bercht, Magda

    2010-01-01

    This paper examines elements from Piaget's and Scherer's theories that are able to offer subsidies for the specification of the affective aspects involved in Virtual Learning Environments (VLE). The affective dimension is characterized by the moods manifested during interactions in virtual space by affective portion of psychological subject. To figure moods out is a way to personalize the pedagogical activities and to understand the student's actions and competence.

  10. Affectivity

    OpenAIRE

    Stenner, Paul; Greco, Monica

    2013-01-01

    The concept of affectivity has assumed central importance in much recent scholarship, and many in the social sciences and humanities now talk of an ‘affective turn’. The concept of affectivity at play in this ‘turn’ remains, however, somewhat vague and slippery. Starting with Silvan Tomkins’ influential theory of affect, this paper will explore the relevance of the general assumptions (or ‘utmost abstractions’) that inform thinking about affectivity. The technological and instrumentalist char...

  11. Potential role of 20S proteasome in maintaining stem cell integrity of human bone marrow stromal cells in prolonged culture expansion

    International Nuclear Information System (INIS)

    Highlights: ► Prolonged culture expansion retards proliferation and induces senescence of hBMSCs. ► Reduced 20S proteasomal activity and expression potentially contribute to cell aging. ► MG132-mediated 20S proteasomal inhibition induces senescence-like phenotype. ► 18α-GA stimulates proteasomal activity and restores replicative senescence. ► 18α-GA retains differentiation without affecting stem cell characterizations. -- Abstract: Human bone marrow stromal cells (hBMSCs) could be used in clinics as precursors of multiple cell lineages following proper induction. Such application is impeded by their characteristically short lifespan, together with the increasing loss of proliferation capability and progressive reduction of differentiation potential after the prolonged culture expansion. In the current study, we addressed the possible role of 20S proteasomes in this process. Consistent with prior reports, long-term in vitro expansion of hBMSCs decreased cell proliferation and increased replicative senescence, accompanied by reduced activity and expression of the catalytic subunits PSMB5 and PSMB1, and the 20S proteasome overall. Application of the proteasome inhibitor MG132 produced a senescence-like phenotype in early passages, whereas treating late-passage cells with 18α-glycyrrhetinic acid (18α-GA), an agonist of 20S proteasomes, delayed the senescence progress, enhancing the proliferation and recovering the capability of differentiation. The data demonstrate that activation of 20S proteasomes assists in counteracting replicative senescence of hBMSCs expanded in vitro.

  12. Dynamic recruitment of active proteasomes into polyglutamine initiated inclusion bodies.

    Science.gov (United States)

    Schipper-Krom, Sabine; Juenemann, Katrin; Jansen, Anne H; Wiemhoefer, Anne; van den Nieuwendijk, Rianne; Smith, Donna L; Hink, Mark A; Bates, Gillian P; Overkleeft, Hermen; Ovaa, Huib; Reits, Eric

    2014-01-01

    Neurodegenerative disorders such as Huntington's disease are hallmarked by neuronal intracellular inclusion body formation. Whether proteasomes are irreversibly recruited into inclusion bodies in these protein misfolding disorders is a controversial subject. In addition, it has been proposed that the proteasomes may become clogged by the aggregated protein fragments, leading to impairment of the ubiquitin-proteasome system. Here, we show by fluorescence pulse-chase experiments in living cells that proteasomes are dynamically and reversibly recruited into inclusion bodies. As these recruited proteasomes remain catalytically active and accessible to substrates, our results challenge the concept of proteasome sequestration and impairment in Huntington's disease, and support the reported absence of proteasome impairment in mouse models of Huntington's disease.

  13. Breast cancer cells: Modulation by melatonin and the ubiquitin-proteasome system--a review.

    Science.gov (United States)

    Vriend, Jerry; Reiter, Russel J

    2015-12-01

    Melatonin inhibits human breast cancer cells stimulated with estrogen. This antiproliferative action depends on the presence of the estrogen receptor alpha (ERα) in the human MCF-7 cell line and is strictly dose-dependent. Since researchers concerned with melatonin and breast cancer have not considered the relevance of the ubiquitin-proteasome system to this research in this review we do so. The fact that the first breast cancer susceptibility gene to be identified, Brca1, functions as a ubiquitin ligase indicates that the ubiquitin-proteasome system has a role in regulating susceptibility to breast cancer. While mutations of this gene increase the incidence of breast cancer, the wild type gene suppresses estrogen-dependent transcriptional events relying on the estrogen receptor ERα. Three other ubiquitin ligases, SCF(Skp2), E6AP and APC, interact directly with ERα at the ERE and AP-1 promoters of ERα target genes. Melatonin, like proteasome inhibitors, decreases estrogen-induced gene transcription. Indeed, it has been reported that melatonin specifically inhibits estrogen-induced transcription mediated by ERα at the ERE and AP1 gene promoters. Herein, we present a model in which the inhibitory action of melatonin on MCF-7 cells is mediated, directly or indirectly, by the ubiquitin-proteasome system. In this model ERα, apoptotic proteins, and cell cycle proteins, all influenced by melatonin, are substrates of key ubiquitin ligases including SCF(Skp2), E6AP, and SCF(B-TrCP). Since dysfunction of the ubiquitin-proteasome system is a risk factor for breast cancer, this model provides a context in which to test the clinical potential, and limitations, of melatonin and proteasome inhibitors. PMID:26363225

  14. Automatic Control of Contextual Interaction Integrated with Affection and Architectural Attentional Control

    Directory of Open Access Journals (Sweden)

    Yanrong Jiang

    2013-03-01

    Full Text Available It is still a challenge for robots to interact with complex environments in a smooth and natural manner. The robot should be aware of its surroundings and inner status to make decisions accordingly and appropriately. Contexts benefit the interaction a lot, such as avoiding frequent interruptions (e.g., the explicit inputting requests and thus are essential for interaction. Other challenges, such as shifting attentional focus to a more important stimulus, etc., are also crucial in interaction control. This paper presents a hybrid automatic control approach for interaction, as well as its integration, with these multiple important factors, aiming at performing natural, human‐like interactions in robots. In particular, a novel approach of architectural attentional control, based on affection is presented, which attempts to shift the attentional focus in a natural manner. Context‐aware computing is combined with interaction to endow the robot with proactive abilities. The long‐term interaction control approaches are described. Emotion and personality are introduced into the interaction and their influence mechanism on interaction is explored. We implemented the proposal in an interactive head robot (IHR and the experimental results indicate the effectiveness.

  15. Proteasome activity influences UV-mediated subnuclear localization changes of NPM.

    Science.gov (United States)

    Moore, Henna M; Bai, Baoyan; Matilainen, Olli; Colis, Laureen; Peltonen, Karita; Laiho, Marikki

    2013-01-01

    UV damage activates cellular stress signaling pathways, causes DNA helix distortions and inhibits transcription by RNA polymerases I and II. In particular, the nucleolus, which is the site of RNA polymerase I transcription and ribosome biogenesis, disintegrates following UV damage. The disintegration is characterized by reorganization of the subnucleolar structures and change of localization of many nucleolar proteins. Here we have queried the basis of localization change of nucleophosmin (NPM), a nucleolar granular component protein, which is increasingly detected in the nucleoplasm following UV radiation. Using photobleaching experiments of NPM-fluorescent fusion protein in live human cells we show that NPM mobility increases after UV damage. However, we show that the increase in NPM nucleoplasmic abundance after UV is independent of UV-activated cellular stress and DNA damage signaling pathways. Unexpectedly, we find that proteasome activity affects NPM redistribution. NPM nucleolar expression was maintained when the UV-treated cells were exposed to proteasome inhibitors or when the expression of proteasome subunits was inhibited using RNAi. However, there was no evidence of increased NPM turnover in the UV damaged cells, or that ubiquitin or ubiquitin recycling affected NPM localization. These findings suggest that proteasome activity couples to nucleolar protein localizations in UV damage stress.

  16. Affective Interaction with a Virtual Character through an fNIRS Brain-Computer Interface

    Directory of Open Access Journals (Sweden)

    Gabor Aranyi

    2016-07-01

    Full Text Available Affective Brain-Computer Interfaces (BCI harness Neuroscience knowledge to develop affective interaction from first principles. In this paper, we explore affective engagement with a virtual agent through Neurofeedback (NF. We report an experiment where subjects engage with a virtual agent by expressing positive attitudes towards her under a NF paradigm. We use for affective input the asymmetric activity in the dorsolateral prefrontal cortex (DL-PFC, which has been previously found to be related to the high-level affective-motivational dimension of approach/avoidance. The magnitude of left-asymmetric DL-PFC activity, measured using fNIRS and treated as a proxy for approach, is mapped onto a control mechanism for the virtual agent’s facial expressions, in which Action Units are activated through a neural network. We carried out an experiment with 18 subjects, which demonstrated that subjects are able to successfully engage with the virtual agent by controlling their mental disposition through NF, and that they perceived the agent’s responses as realistic and consistent with their projected mental disposition. This interaction paradigm is particularly relevant in the case of affective BCI as it facilitates the volitional activation of specific areas normally not under conscious control. Overall, our contribution reconciles a model of affect derived from brain metabolic data with an ecologically valid, yet computationally controllable, virtual affective communication environment.

  17. Affective Interaction with a Virtual Character Through an fNIRS Brain-Computer Interface.

    Science.gov (United States)

    Aranyi, Gabor; Pecune, Florian; Charles, Fred; Pelachaud, Catherine; Cavazza, Marc

    2016-01-01

    Affective brain-computer interfaces (BCI) harness Neuroscience knowledge to develop affective interaction from first principles. In this article, we explore affective engagement with a virtual agent through Neurofeedback (NF). We report an experiment where subjects engage with a virtual agent by expressing positive attitudes towards her under a NF paradigm. We use for affective input the asymmetric activity in the dorsolateral prefrontal cortex (DL-PFC), which has been previously found to be related to the high-level affective-motivational dimension of approach/avoidance. The magnitude of left-asymmetric DL-PFC activity, measured using functional near infrared spectroscopy (fNIRS) and treated as a proxy for approach, is mapped onto a control mechanism for the virtual agent's facial expressions, in which action units (AUs) are activated through a neural network. We carried out an experiment with 18 subjects, which demonstrated that subjects are able to successfully engage with the virtual agent by controlling their mental disposition through NF, and that they perceived the agent's responses as realistic and consistent with their projected mental disposition. This interaction paradigm is particularly relevant in the case of affective BCI as it facilitates the volitional activation of specific areas normally not under conscious control. Overall, our contribution reconciles a model of affect derived from brain metabolic data with an ecologically valid, yet computationally controllable, virtual affective communication environment. PMID:27462216

  18. The Interactive Effects of Affect Lability, Negative Urgency, and Sensation Seeking on Young Adult Problematic Drinking

    OpenAIRE

    Kenny Karyadi; Ayca Coskunpinar; Dir, Allyson L.; Cyders, Melissa A.

    2013-01-01

    Prior studies have suggested that affect lability might reduce the risk for problematic drinking among sensation seekers by compensating for their deficiencies in emotional reactivity and among individuals high on negative urgency by disrupting stable negative emotions. Due to the high prevalence of college drinking, this study examined whether affect lability interacted with sensation seeking and negative urgency to influence college student problematic drinking. 414 college drinkers (mean a...

  19. PiZ mouse liver accumulates polyubiquitin conjugates that associate with catalytically active 26S proteasomes.

    Directory of Open Access Journals (Sweden)

    Christopher J Haddock

    Full Text Available Accumulation of aggregation-prone human alpha 1 antitrypsin mutant Z (AT-Z protein in PiZ mouse liver stimulates features of liver injury typical of human alpha 1 antitrypsin type ZZ deficiency, an autosomal recessive genetic disorder. Ubiquitin-mediated proteolysis by the 26S proteasome counteracts AT-Z accumulation and plays other roles that, when inhibited, could exacerbate the injury. However, it is unknown how the conditions of AT-Z mediated liver injury affect the 26S proteasome. To address this question, we developed a rapid extraction strategy that preserves polyubiquitin conjugates in the presence of catalytically active 26S proteasomes and allows their separation from deposits of insoluble AT-Z. Compared to WT, PiZ extracts had about 4-fold more polyubiquitin conjugates with no apparent change in the levels of the 26S and 20S proteasomes, and unassembled subunits. The polyubiquitin conjugates had similar affinities to ubiquitin-binding domain of Psmd4 and co-purified with similar amounts of catalytically active 26S complexes. These data show that polyubiquitin conjugates were accumulating despite normal recruitment to catalytically active 26S proteasomes that were available in excess, and suggest that a defect at the 26S proteasome other than compromised binding to polyubiquitin chain or peptidase activity played a role in the accumulation. In support of this idea, PiZ extracts were characterized by high molecular weight, reduction-sensitive forms of selected subunits, including ATPase subunits that unfold substrates and regulate access to proteolytic core. Older WT mice acquired similar alterations, implying that they result from common aspects of oxidative stress. The changes were most pronounced on unassembled subunits, but some subunits were altered even in the 26S proteasomes co-purified with polyubiquitin conjugates. Thus, AT-Z protein aggregates indirectly impair degradation of polyubiquitinated proteins at the level of the 26S

  20. Synergistic apoptosis induction in leukemic cells by the phosphatase inhibitor salubrinal and proteasome inhibitors.

    Directory of Open Access Journals (Sweden)

    Hannes C A Drexler

    Full Text Available BACKGROUND: Cells adapt to endoplasmic reticulum (ER-stress by arresting global protein synthesis while simultaneously activating specific transcription factors and their downstream targets. These processes are mediated in part by the phosphorylation-dependent inactivation of the translation initiation factor eIF2alpha. Following restoration of homeostasis protein synthesis is resumed when the serine/threonine-protein phosphatase PP1 dephosphorylates and reactivates eIF2alpha. Proteasome inhibitors, used to treat multiple myeloma patients evoke ER-stress and apoptosis by blocking the ER-associated degradation of misfolded proteins (ERAD, however, the role of eIF2alpha phosphorylation in leukemic cells under conditions of proteasome inhibitor-mediated ER stress is currently unclear. METHODOLOGY AND PRINCIPAL FINDINGS: Bcr-Abl-positive and negative leukemic cell lines were used to investigate the functional implications of PP1-related phosphatase activities on eIF2alpha phosphorylation in proteasome inhibitor-mediated ER stress and apoptosis. Rather unexpectedly, salubrinal, a recently identified PP1 inhibitor capable to protect against ER stress in various model systems, strongly synergized with proteasome inhibitors to augment apoptotic death of different leukemic cell lines. Salubrinal treatment did not affect the phosphorlyation status of eIF2alpha. Furthermore, the proapoptotic effect of salubrinal occurred independently from the chemical nature of the proteasome inhibitor, was recapitulated by a second unrelated phosphatase inhibitor and was unaffected by overexpression of a dominant negative eIF2alpha S51A variant that can not be phosphorylated. Salubrinal further aggravated ER-stress and proteotoxicity inflicted by the proteasome inhibitors on the leukemic cells since characteristic ER stress responses, such as ATF4 and CHOP synthesis, XBP1 splicing, activation of MAP kinases and eventually apoptosis were efficiently abrogated by the

  1. Applied techniques for mining natural proteasome inhibitors.

    Science.gov (United States)

    Stein, Martin L; Groll, Michael

    2014-01-01

    In eukaryotic cells, the ubiquitin-proteasome-system (UPS) is responsible for the non-lysosomal degradation of proteins and plays a pivotal role in such vital processes as protein homeostasis, antigen processing or cell proliferation. Therefore, it is an attractive drug target with various applications in cancer and immunosuppressive therapies. Being an evolutionary well conserved pathway, many pathogenic bacteria have developed small molecules, which modulate the activity of their hosts' UPS components. Such natural products are, due to their stepwise optimization over the millennia, highly potent in terms of their binding mechanisms, their bioavailability and selectivity. Generally, this makes bioactive natural products an ideal starting point for the development of novel drugs. Since four out of the ten best seller drugs are natural product derivatives, research in this field is still of unfathomable value for the pharmaceutical industry. The currently most prominent example for the successful exploitation of a natural compound in the UPS field is carfilzomib (Kyprolis®), which represents the second FDA approved drug targeting the proteasome after the admission of the blockbuster bortezomib (Velcade®) in 2003. On the other hand side of the spectrum, ONX 0914, which is derived from the same natural product as carfilzomib, has been shown to selectively inhibit the immune response related branch of the pathway. To date, there exists a huge potential of UPS inhibitors with regard to many diseases. Both approved drugs against the proteasome show severe side effects, adaptive resistances and limited applicability, thus the development of novel compounds with enhanced properties is a main objective of active research. In this review, we describe the techniques, which can be utilized for the discovery of novel natural inhibitors, which in particular block the 20S proteasomal activity. In addition, we will illustrate the successful implementation of a recently

  2. Situational Motivation and Perceived Intensity: Their Interaction in Predicting Changes in Positive Affect from Physical Activity

    Directory of Open Access Journals (Sweden)

    Eva Guérin

    2012-01-01

    Full Text Available There is evidence that affective experiences surrounding physical activity can contribute to the proper self-regulation of an active lifestyle. Motivation toward physical activity, as portrayed by self-determination theory, has been linked to positive affect, as has the intensity of physical activity, especially of a preferred nature. The purpose of this experimental study was to examine the interaction between situational motivation and intensity [i.e., ratings of perceived exertion (RPE] in predicting changes in positive affect following an acute bout of preferred physical activity, namely, running. Fourty-one female runners engaged in a 30-minute self-paced treadmill run in a laboratory context. Situational motivation for running, pre- and post-running positive affect, and RPE were assessed via validated self-report questionnaires. Hierarchical regression analyses revealed a significant interaction effect between RPE and introjection (P<.05 but not between RPE and identified regulation or intrinsic motivation. At low levels of introjection, the influence of RPE on the change in positive affect was considerable, with higher RPE ratings being associated with greater increases in positive affect. The implications of the findings in light of SDT principles as well as the potential contingencies between the regulations and RPE in predicting positive affect among women are discussed.

  3. User Experience of Mobile Interactivity: How Do Mobile Websites Affect Attitudes and Relational Outcomes?

    Science.gov (United States)

    Dou, Xue

    2013-01-01

    Mobile media offer new opportunities for fostering communications between individuals and companies. Corporate websites are being increasingly accessed via smart phones and companies are scrambling to offer a mobile-friendly user experience on their sites. However, very little is known about how interactivity in the mobile context affects user…

  4. Dopamine D4 receptor polymorphism and sex interact to predict children's affective knowledge.

    Science.gov (United States)

    Ben-Israel, Sharon; Uzefovsky, Florina; Ebstein, Richard P; Knafo-Noam, Ariel

    2015-01-01

    Affective knowledge, the ability to understand others' emotional states, is considered to be a fundamental part in efficient social interaction. Affective knowledge can be seen as related to cognitive empathy, and in the framework of theory of mind (ToM) as affective ToM. Previous studies found that cognitive empathy and ToM are heritable, yet little is known regarding the specific genes involved in individual variability in affective knowledge. Investigating the genetic basis of affective knowledge is important for understanding brain mechanisms underlying socio-cognitive abilities. The 7-repeat (7R) allele within the third exon of the dopamine D4 receptor gene (DRD4-III) has been a focus of interest, due to accumulated knowledge regarding its relevance to individual differences in social behavior. A recent study suggests that an interaction between the DRD4-III polymorphism and sex is associated with cognitive empathy among adults. We aimed to examine the same association in two childhood age groups. Children (N = 280, age 3.5 years, N = 283, age 5 years) participated as part of the Longitudinal Israel Study of Twins. Affective knowledge was assessed through children's responses to an illustrated story describing different emotional situations, told in a laboratory setting. The findings suggest a significant interaction between sex and the DRD4-III polymorphism, replicated in both age groups. Boy carriers of the 7R allele had higher affective knowledge scores than girls, whereas in the absence of the 7R there was no significant sex effect on affective knowledge. The results support the importance of DRD4-III polymorphism and sex differences to social development. Possible explanations for differences from adult findings are discussed, as are pathways for future studies. PMID:26157401

  5. Dopamine D4 Receptor Polymorphism and Sex Interact to Predict Children's Affective Knowledge

    Directory of Open Access Journals (Sweden)

    Sharon eBen-Israel

    2015-06-01

    Full Text Available Affective knowledge, the ability to understand others’ emotional states, is considered to be a fundamental part in efficient social interaction. Affective knowledge can be seen as related to cognitive empathy, and in the framework of Theory of Mind (ToM as affective ToM. Previous studies found that cognitive empathy and ToM are heritable, yet little is known regarding the specific genes involved in individual variability in affective knowledge. Investigating the genetic basis of affective knowledge is important for understanding brain mechanisms underlying socio-cognitive abilities. The 7-repeat (7R allele within the third exon of the Dopamine D4 receptor gene (DRD4-III has been a focus of interest, due to accumulated knowledge regarding its relevance to individual differences in prosocial behavior. A recent study suggests that an interaction between the DRD4-III polymorphism and sex is associated with cognitive empathy among adults. We aimed to examine the same association in two childhood age groups. Children (N = 280, age 3.5 years, N = 283, age 5 years participated as part of the Longitudinal Israel Study of Twins (LIST. Affective knowledge was assessed through children’s responses to an illustrated story describing different emotional situations, told in a laboratory setting. The findings suggest a significant interaction between sex and the DRD4-III polymorphism, replicated in both age groups. Boy carriers of the 7R allele had higher affective knowledge scores than girls, whereas in the absence of the 7R there was no significant sex effect on affective knowledge. The results support the importance of DRD4-III polymorphism and sex differences to social development. Possible explanations for differences from adult findings are discussed, as are pathways for future studies.

  6. Approaches to Affective Computing and Learning towards Interactive Decision Making in Process Control Engineering

    Institute of Scientific and Technical Information of China (English)

    SU Chong; LI Hong-Guang

    2013-01-01

    Numerous multi-objective decision-making problems related to industrial process control engineering such as control and operation performance evaluation are being resolved through human-computer interactions.With regard to the problems that traditional interactive evolutionary computing approaches suffer i.e.,limited searching ability and human's strong subjectivity in multi-objective-attribute decision-making,a novel affective computing and learning solution adapted to human-computer interaction mechanism is explicitly proposed.Therein,a kind of stimulating response based affective computing model (STAM) is constructed,along with quantitative relations between affective space and human's subjective preferences.Thereafter,affective learning strategies based on genetic algorithms are introduced which are responsible for gradually grasping essentials in human's subjective judgments in decision-making,reducing human's subjective fatigue as well as making the decisions more objective and scientific.Affective learning algorithm's complexity and convergence analysis are shown in Appendices A and B.To exemplify applications of the proposed methods,ad-hoc test functions and PID parameter tuning are suggested as case studies,giving rise to satisfying results and showing validity of the contributions.

  7. Toward interactive context-aware affective educational recommendations in computer-assisted language learning

    Science.gov (United States)

    Santos, Olga C.; Saneiro, Mar; Boticario, Jesus G.; Rodriguez-Sanchez, M. C.

    2016-01-01

    This work explores the benefits of supporting learners affectively in a context-aware learning situation. This features a new challenge in related literature in terms of providing affective educational recommendations that take advantage of ambient intelligence and are delivered through actuators available in the environment, thus going beyond previous approaches which provided computer-based recommendation that present some text or tell aloud the learner what to do. To address this open issue, we have applied TORMES elicitation methodology, which has been used to investigate the potential of ambient intelligence for making more interactive recommendations in an emotionally challenging scenario (i.e. preparing for the oral examination of a second language learning course). Arduino open source electronics prototyping platform is used both to sense changes in the learners' affective state and to deliver the recommendation in a more interactive way through different complementary sensory communication channels (sight, hearing, touch) to cope with a universal design. An Ambient Intelligence Context-aware Affective Recommender Platform (AICARP) has been built to support the whole experience, which represents a progress in the state of the art. In particular, we have come up with what is most likely the first interactive context-aware affective educational recommendation. The value of this contribution lies in discussing methodological and practical issues involved.

  8. Differential regulation of the REGγ–proteasome pathway by p53/TGF-β signalling and mutant p53 in cancer cells

    OpenAIRE

    Ali, Amjad; Wang, Zhuo; Fu, Junjiang; Lei, Ji; Liu, Jiang; Lei, Li; Wang,; Chen, Jiwu; Caulin, Carlos; Jeffrey, N. Myers; Zhang, Pei; Xiao, Jianru; Zhang, Bianhong; Li, Xiaotao

    2013-01-01

    Proteasome activity is frequently enhanced in cancer to accelerate metastasis and tumorigenesis. REGγ, a proteasome activator known to promote p53/p21/p16 degradation, is often overexpressed in cancer cells. Here we show that p53/TGF-β signalling inhibits the REGγ–20S proteasome pathway by repressing REGγ expression. Smad3 and p53 interact on the REGγ promoter via the p53RE/SBE region. Conversely, mutant p53 binds to the REGγ promoter and recruits p300. Importantly, mutant p53 prevents Smad3/...

  9. Acidification and warming affect both a calcifying predator and prey, but not their interaction

    DEFF Research Database (Denmark)

    Landes, Anja; Zimmer, Martin

    2012-01-01

    Both ocean warming and acidification have been demonstrated to affect the growth, performance and reproductive success of calcifying invertebrates. However, relatively little is known regarding how such environmental change may affect interspecific interactions. We separately treated green crabs...... Carcinus maenas and periwinkles Littorina littorea under conditions that mimicked either ambient conditions (control) or warming and acidification, both separately and in combination, for 5 mo. After 5 mo, the predators, prey and predator-prey interactions were screened for changes in response...... to environmental change. Acidification negatively affected the closer-muscle length of the crusher chela and correspondingly the claw-strength increment in C. maenas. The effects of warming and/or acidification on L. littorea were less consistent but indicated weaker shells in response to acidification...

  10. Nuclear effects of ethanol-induced proteasome inhibition in liver cells

    Institute of Scientific and Technical Information of China (English)

    Fawzia Bardag-Gorce

    2009-01-01

    Alcohol ingestion causes alteration in several cellular mechanisms, and leads to inflammation, apoptosis,immunological response defects, and fibrosis. These phenomena are associated with significant changes in the epigenetic mechanisms, and subsequently,to liver cell memory. The ubiquitin-proteasome pathway is one of the vital pathways in the cell that becomes dysfunctionial as a result of chronic ethanol consumption. Inhibition of the proteasome activity in the nucleus causes changes in the turnover of transcriptional factors, histone modifying enzymes,and therefore, affects epigenetic mechanisms.Alcohol consumption has been associated with an increase in histone acetylation and a decrease in histone methylation, which leads to gene expression changes. DNA and histone modifications that result from ethanol-induced proteasome inhibition are key players in regulating gene expression, especially genes involved in the cell cycle, immunological responses,and metabolism of ethanol. The present review highlights the consequences of ethanol-induced proteasome inhibition in the nucleus of liver cells that are chronically exposed to ethanol.

  11. Production of Proteasome Inhibitor Syringolin A by the Endophyte Rhizobium sp. Strain AP16

    Science.gov (United States)

    Bigler, Laurent; Dudler, Robert

    2014-01-01

    Syringolin A, the product of a mixed nonribosomal peptide synthetase/polyketide synthase encoded by the syl gene cluster, is a virulence factor secreted by certain Pseudomonas syringae strains. Together with the glidobactins produced by a number of beta- and gammaproteobacterial human and animal pathogens, it belongs to the syrbactins, a structurally novel class of proteasome inhibitors. In plants, proteasome inhibition by syringolin A-producing P. syringae strains leads to the suppression of host defense pathways requiring proteasome activity, such as the ones mediated by salicylic acid and jasmonic acid. Here we report the discovery of a syl-like gene cluster with some unusual features in the alphaproteobacterial endophyte Rhizobium sp. strain AP16 that encodes a putative syringolin A-like synthetase whose components share 55% to 65% sequence identity (72% to 79% similarity) at the amino acid level. As revealed by average nucleotide identity (ANI) calculations, this strain likely belongs to the same species as biocontrol strain R. rhizogenes K84 (formely known as Agrobacterium radiobacter K84), which, however, carries a nonfunctional deletion remnant of the syl-like gene cluster. Here we present a functional analysis of the syl-like gene cluster of Rhizobium sp. strain AP16 and demonstrate that this endophyte synthesizes syringolin A and some related minor variants, suggesting that proteasome inhibition by syrbactin production can be important not only for pathogens but also for endophytic bacteria in the interaction with their hosts. PMID:24727275

  12. The ubiquitin–proteasome system as a molecular target in solid tumors: an update on bortezomib

    Directory of Open Access Journals (Sweden)

    A Milano

    2009-06-01

    Full Text Available A Milano,1 F Perri,2 F Caponigro21Sandro Pitigliani Medical Oncology Unit, Department of Oncology, Hospital of Prato, Istituto Toscano Tumori, Prato, Italy; 2Head and Neck Medical Oncology Unit, National Tumour institute of Naples, Naples, ItalyAbstract: The ubiquitin–proteasome system has become a promising molecular target in cancer therapy due to its critical role in cellular protein degradation, interaction with cell cycle and apoptosis regulation, and unique mechanism of action. Bortezomib (PS-341 is a potent and specific reversible proteasome inhibitor, which has shown strong in vitro antitumor activity as single agent and in combination with other cytotoxic drugs in a broad spectrum of hematological and solid malignancies. In preclinical studies, bortezomib induced apoptosis of malignant cells through the inhibition of NF-κB and stabilization of pro-apoptotic proteins. Bortezomib also promotes chemo- and radiosensitization of malignant cells in vitro and inhibits tumor growth in murine xenograft models. The proteasome has been established as a relevant target in hematologic malignancies and bortezomib has been approved for the treatment of multiple myeloma. This review summarizes recent data from clinical trials in solid tumors. Keywords: proteasome, bortezomib, NF-κB, clinical studies, solid tumors

  13. Suppression of the Oncogenic Transcription Factor FOXM1 by Proteasome Inhibitors

    Directory of Open Access Journals (Sweden)

    Andrei L. Gartel

    2014-01-01

    Full Text Available The oncogenic transcription factor FOXM1 is one of the key regulators of tumorigenesis. We found that FOXM1 upregulates its own transcription and its protein stability depends on its interaction with the chaperone nucleophosmin. We also determined that FOXM1 is negatively regulated by the tumor suppressor p53. We identified the thiazole antibiotics Siomycin A and thiostrepton as inhibitors of transcriptional activity and FOXM1 expression via proteasome inhibition. In addition, we found that all tested proteasome inhibitors target FOXM1. We showed synergy between thiostrepton and bortezomib in different human cancer cell lines and in vivo. We generated isogenic human cancer cell lines of different origin with wild-type p53 or p53 knockdown and we demonstrated that proteasome inhibitors induce p53-independent apoptosis in these cells. Using RNA-interference or proteasome inhibitors to inhibit FOXM1 we found that suppression of FOXM1 sensitized human cancer cells to apoptosis induced by DNA-damaging agents or oxidative stress. We encapsulated thiostrepton into micelle-nanoparticles and after injection we detected accumulation of nanoparticles in tumors and in the livers of treated mice. This treatment led to inhibition of human xenograft tumor growth in nude mice. Our data indicate that targeting FOXM1 increases apoptosis and inhibits tumor growth.

  14. The recognition of ubiquitinated proteins by the proteasome.

    Science.gov (United States)

    Grice, Guinevere L; Nathan, James A

    2016-09-01

    The ability of ubiquitin to form up to eight different polyubiquitin chain linkages generates complexity within the ubiquitin proteasome system, and accounts for the diverse roles of ubiquitination within the cell. Understanding how each type of ubiquitin linkage is correctly interpreted by ubiquitin binding proteins provides important insights into the link between chain recognition and cellular fate. A major function of ubiquitination is to signal degradation of intracellular proteins by the 26S proteasome. Lysine-48 (K48) linked polyubiquitin chains are well established as the canonical signal for proteasomal degradation, but recent studies show a role for other ubiquitin linked chains in facilitating degradation by the 26S proteasome. Here, we review how different types of polyubiquitin linkage bind to ubiquitin receptors on the 26S proteasome, how they signal degradation and discuss the implications of ubiquitin chain linkage in regulating protein breakdown by the proteasome. PMID:27137187

  15. Interactive effects of trait and state affect on top-down control of attention.

    Science.gov (United States)

    Hur, Juyoen; Miller, Gregory A; McDavitt, Jenika R B; Spielberg, Jeffrey M; Crocker, Laura D; Infantolino, Zachary P; Towers, David N; Warren, Stacie L; Heller, Wendy

    2015-08-01

    Few studies have investigated how attentional control is affected by transient affective states while taking individual differences in affective traits into consideration. In this study, participants completed a color-word Stroop task immediately after undergoing a positive, neutral or negative affective context manipulation (ACM). Behavioral performance was unaffected by any ACM considered in isolation. For individuals high in trait negative affect (NA), performance was impaired by the negative but not the positive or neutral ACM. Neuroimaging results indicate that activity in primarily top-down control regions of the brain (inferior frontal gyrus and dorsal anterior cingulate cortex) was suppressed in the presence of emotional arousal (both negative and positive ACMs). This effect appears to have been exacerbated or offset by co-occurring activity in other top-down control regions (parietal) and emotion processing regions (orbitofrontal cortex, amygdala and nucleus accumbens) as a function of the valence of state affect (positive or negative) and trait affect (trait NA or trait PA). Neuroimaging results are consistent with behavioral findings. In combination, they indicate both additive and interactive influences of trait and state affect on top-down control of attention. PMID:25556211

  16. 26S Proteasome: Hunter and Prey in Auxin Signaling.

    Science.gov (United States)

    Kong, Xiangpei; Zhang, Liangran; Ding, Zhaojun

    2016-07-01

    Auxin binds to TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALLING F-BOX proteins (TIR1/AFBs) and promotes the degradation of Aux/IAA transcriptional repressors. The proteasome regulator PROTEASOME REGULATOR1 (PTRE1) has now been shown to be required for auxin-mediated repression of 26S proteasome activity, thus providing new insights into the fine-tuning of the homoeostasis of Aux/IAA proteins and auxin signaling. PMID:27246455

  17. Viruses and the 26S proteasome: hacking into destruction.

    Science.gov (United States)

    Banks, Lawrence; Pim, David; Thomas, Miranda

    2003-08-01

    The discovery that the human papillomavirus E6 oncoprotein could direct the ubiquitination and degradation of the p53 tumour suppressor at the 26S proteasome was the beginning of a new view on virus-host interactions. A decade later, a plethora of viral proteins have been shown to direct host-cell proteins for proteolytic degradation. These activities are required for various aspects of the virus life-cycle from entry, through replication and enhanced cell survival, to viral release. As with oncogenes and cell-cycle control, the study of apparently simple viruses has provided a wealth of information on the function of a whole class of cellular proteins whose function is arguably as important as that of the kinases: the ubiquitin-protein ligases.

  18. The role of ubiquitin-proteasome pathway in spermatogenesis.

    Science.gov (United States)

    Lianhua, Dong; Maoliang, Ran; Zhi, Li; Fuzhi, Peng; Bin, Chen

    2016-09-01

    Ubiquitin-proteasome pathway (UPP) is the main pathway of protein degradation in eukaryotic cells. The UPP plays very important roles in cell cycle progression, apoptosis, stress response and growth and development through regulating protein interaction, protein activity, protein localization and signal transduction. Previous studies have shown that the UPP is essential for regulating acrosome and tail biogenesis during spermatogenesis in human and animals. The dysregulation of UPP during spermatogenesis results in sperm deformity and reduced sperm motility and leads to reproductive system diseases such as oligospermatism, infertility and testicular tumors. In this review, we summarized the signal transduction and regulation mechanism of UPP in spermatogenesis, which may provide references for future studies. PMID:27644740

  19. Neural coding of cooperative vs. affective human interactions: 150 ms to code the action's purpose.

    Directory of Open Access Journals (Sweden)

    Alice Mado Proverbio

    Full Text Available The timing and neural processing of the understanding of social interactions was investigated by presenting scenes in which 2 people performed cooperative or affective actions. While the role of the human mirror neuron system (MNS in understanding actions and intentions is widely accepted, little is known about the time course within which these aspects of visual information are automatically extracted. Event-Related Potentials were recorded in 35 university students perceiving 260 pictures of cooperative (e.g., 2 people dragging a box or affective (e.g., 2 people smiling and holding hands interactions. The action's goal was automatically discriminated at about 150-170 ms, as reflected by occipito/temporal N170 response. The swLORETA inverse solution revealed the strongest sources in the right posterior cingulate cortex (CC for affective actions and in the right pSTS for cooperative actions. It was found a right hemispheric asymmetry that involved the fusiform gyrus (BA37, the posterior CC, and the medial frontal gyrus (BA10/11 for the processing of affective interactions, particularly in the 155-175 ms time window. In a later time window (200-250 ms the processing of cooperative interactions activated the left post-central gyrus (BA3, the left parahippocampal gyrus, the left superior frontal gyrus (BA10, as well as the right premotor cortex (BA6. Women showed a greater response discriminative of the action's goal compared to men at P300 and anterior negativity level (220-500 ms. These findings might be related to a greater responsiveness of the female vs. male MNS. In addition, the discriminative effect was bilateral in women and was smaller and left-sided in men. Evidence was provided that perceptually similar social interactions are discriminated on the basis of the agents' intentions quite early in neural processing, differentially activating regions devoted to face/body/action coding, the limbic system and the MNS.

  20. N- and O-methylation of sphingomyelin markedly affects its membrane properties and interactions with cholesterol

    DEFF Research Database (Denmark)

    Bjorkbom, A.; Rog, T.; Kankaanpaa, P.;

    2011-01-01

    via the amide nitrogen, whereas 2-NH methylation did not similarly affect hydrogen bonding via the 3-OH. The interactions of sterols with the methylated SM analogs were markedly affected. 3-OH methylation almost completely eliminated the capacity of the SM analog to form sterol-enriched ordered...... domains, whereas the 2-NH methylated SM analog formed sterol-enriched domains but these were less thermostable (and thus less ordered) than the domains formed by PSM. Cholestatrienol affinity to bilayers containing methylated SM analogs was also markedly reduced as compared to its affinity for bilayers...

  1. Normal and mutant HTT interact to affect clinical severity and progression in Huntington disease

    DEFF Research Database (Denmark)

    Aziz, N A; Jurgens, C K; Landwehrmeyer, G B;

    2009-01-01

    OBJECTIVE: Huntington disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG repeat expansion in the HD gene (HTT). We aimed to assess whether interaction between CAG repeat sizes in the mutant and normal allele could affect disease severity and progression. METHODS: Using...... with less severe symptoms and pathology. CONCLUSIONS: Increasing CAG repeat size in normal HTT diminishes the association between mutant CAG repeat size and disease severity and progression in Huntington disease. The underlying mechanism may involve interaction of the polyglutamine domains of normal...

  2. Insulin alleviates degradation of skeletal muscle protein by inhibiting the ubiquitin-proteasome system in septic rats

    Directory of Open Access Journals (Sweden)

    Gao Tao

    2011-06-01

    Full Text Available Abstract Hypercatabolism is common under septic conditions. Skeletal muscle is the main target organ for hypercatabolism, and this phenomenon is a vital factor in the deterioration of recovery in septic patients. In skeletal muscle, activation of the ubiquitin-proteasome system plays an important role in hypercatabolism under septic status. Insulin is a vital anticatabolic hormone and previous evidence suggests that insulin administration inhibits various steps in the ubiquitin-proteasome system. However, whether insulin can alleviate the degradation of skeletal muscle protein by inhibiting the ubiquitin-proteasome system under septic condition is unclear. This paper confirmed that mRNA and protein levels of the ubiquitin-proteasome system were upregulated and molecular markers of skeletal muscle proteolysis (tyrosine and 3-methylhistidine simultaneously increased in the skeletal muscle of septic rats. Septic rats were infused with insulin at a constant rate of 2.4 mU.kg-1.min-1 for 8 hours. Concentrations of mRNA and proteins of the ubiquitin-proteasome system and molecular markers of skeletal muscle proteolysis were mildly affected. When the insulin infusion dose increased to 4.8 mU.kg-1.min-1, mRNA for ubiquitin, E2-14 KDa, and the C2 subunit were all sharply downregulated. At the same time, the levels of ubiquitinated proteins, E2-14KDa, and the C2 subunit protein were significantly reduced. Tyrosine and 3-methylhistidine decreased significantly. We concluded that the ubiquitin-proteasome system is important skeletal muscle hypercatabolism in septic rats. Infusion of insulin can reverse the detrimental metabolism of skeletal muscle by inhibiting the ubiquitin-proteasome system, and the effect is proportional to the insulin infusion dose.

  3. Warming, CO2, and nitrogen deposition interactively affect a plant-pollinator mutualism.

    Science.gov (United States)

    Hoover, Shelley E R; Ladley, Jenny J; Shchepetkina, Anastasia A; Tisch, Maggie; Gieseg, Steven P; Tylianakis, Jason M

    2012-03-01

    Environmental changes threaten plant-pollinator mutualisms and their critical ecosystem service. Drivers such as land use, invasions and climate change can affect pollinator diversity or species encounter rates. However, nitrogen deposition, climate warming and CO(2) enrichment could interact to disrupt this crucial mutualism by altering plant chemistry in ways that alter floral attractiveness or even nutritional rewards for pollinators. Using a pumpkin model system, we show that these drivers non-additively affect flower morphology, phenology, flower sex ratios and nectar chemistry (sugar and amino acids), thereby altering the attractiveness of nectar to bumble bee pollinators and reducing worker longevity. Alarmingly, bees were attracted to, and consumed more, nectar from a treatment that reduced their survival by 22%. Thus, three of the five major drivers of global environmental change have previously unknown interactive effects on plant-pollinator mutualisms that could not be predicted from studies of individual drivers in isolation.

  4. Effect of proteasome inhibitors on expression of HLA-G isoforms.

    Science.gov (United States)

    Poláková, K; Bandzuchová, E; Bystrická, M; Pancuchárová, H; Russ, G

    2006-01-01

    HLA-G primary transcript is alternatively spliced into a number of mRNAs. In addition to full length HLA-G1 protein isoform these mRNAs might also encode truncated HLA-G protein isoforms lacking one or two extracellular domains. Whereas HLA-G1 protein isoform is regularly identified, truncated HLAG protein isoforms are not detected even if all alternative spliced mRNAs are present in cells. The absence of entire domain(s) renders the truncated HLA-G protein isoforms incapable of binding peptide and beta2-microglobulin. These features of truncated HLA-G protein isoforms may result in their rapid degradation by proteasomes. Here we show that despite the presence of all alternatively spliced HLA-G transcripts in JEG-3 cells pretreated with proteasome inhibitors only a full length HLA-G1 protein isoform was regularly detected. Interestingly, immunoblot analysis showed slight increase of HLA-G1 protein in cells pretreated with proteasome inhibitors, although the expression of HLA-G1 transcript was basically not affected. Expression of HLA-G3 transcript increased in JEG-3 cells pre-incubated with LLL, however, neither HLA-G3 nor other HLA-G short protein isoform was regularly detected. In K562 transfectants proteasome inhibitor LLL greatly enhanced expression of the HLA-G1 and -G2 transcripts as well as corresponding protein isoforms. Flow cytometry analysis showed that in cells pre-treated with proteasome inhibitors cell surface expression of HLA-G1 protein decreased but the quantity of intracellularly localized HLA-G antigens increased. Altogether our results suggest that truncated HLA-G proteins isoforms are not detected in JEG-3 cells as a result of their instability and the low translation efficiency of truncated HLA-G transcripts.

  5. Syrbactin Structural Analog TIR-199 Blocks Proteasome Activity and Induces Tumor Cell Death.

    Science.gov (United States)

    Bachmann, André S; Opoku-Ansah, John; Ibarra-Rivera, Tannya R; Yco, Lisette P; Ambadi, Sudhakar; Roberts, Christopher C; Chang, Chia-En A; Pirrung, Michael C

    2016-04-15

    Multiple myeloma is an aggressive hematopoietic cancer of plasma cells. The recent emergence of three effective FDA-approved proteasome-inhibiting drugs, bortezomib (Velcade®), carfilzomib (Kyprolis®), and ixazomib (Ninlaro®), confirms that proteasome inhibitors are therapeutically useful against neoplastic disease, in particular refractory multiple myeloma and mantle cell lymphoma. This study describes the synthesis, computational affinity assessment, and preclinical evaluation of TIR-199, a natural product-derived syrbactin structural analog. Molecular modeling and simulation suggested that TIR-199 covalently binds each of the three catalytic subunits (β1, β2, and β5) and revealed key interaction sites. In vitro and cell culture-based proteasome activity measurements confirmed that TIR-199 inhibits the proteasome in a dose-dependent manner and induces tumor cell death in multiple myeloma and neuroblastoma cells as well as other cancer types in the NCI-60 cell panel. It is particularly effective against kidney tumor cell lines, with >250-fold higher anti-tumor activities than observed with the natural product syringolin A. In vivo studies in mice revealed a maximum tolerated dose of TIR-199 at 25 mg/kg. The anti-tumor activity of TIR-199 was confirmed in hollow fiber assays in mice. Adverse drug reaction screens in a kidney panel revealed no off-targets of concern. This is the first study to examine the efficacy of a syrbactin in animals. Taken together, the results suggest that TIR-199 is a potent new proteasome inhibitor with promise for further development into a clinical drug for the treatment of multiple myeloma and other forms of cancer.

  6. The proteasomal subunit Rpn6 is a molecular clamp holding the core and regulatory subcomplexes together.

    Science.gov (United States)

    Pathare, Ganesh Ramnath; Nagy, István; Bohn, Stefan; Unverdorben, Pia; Hubert, Agnes; Körner, Roman; Nickell, Stephan; Lasker, Keren; Sali, Andrej; Tamura, Tomohiro; Nishioka, Taiki; Förster, Friedrich; Baumeister, Wolfgang; Bracher, Andreas

    2012-01-01

    Proteasomes execute the degradation of most cellular proteins. Although the 20S core particle (CP) has been studied in great detail, the structure of the 19S regulatory particle (RP), which prepares ubiquitylated substrates for degradation, has remained elusive. Here, we report the crystal structure of one of the RP subunits, Rpn6, and we describe its integration into the cryo-EM density map of the 26S holocomplex at 9.1 Å resolution. Rpn6 consists of an α-solenoid-like fold and a proteasome COP9/signalosome eIF3 (PCI) module in a right-handed suprahelical configuration. Highly conserved surface areas of Rpn6 interact with the conserved surfaces of the Pre8 (alpha2) and Rpt6 subunits from the alpha and ATPase rings, respectively. The structure suggests that Rpn6 has a pivotal role in stabilizing the otherwise weak interaction between the CP and the RP.

  7. "God of Small Things": Service Interaction's Roots in Regulatory Focus and Affectivity

    OpenAIRE

    Tali Seger-Guttmann; Iris Vilnai-Yavetz

    2014-01-01

    We link regulatory focus, positive and negative affective states, and service behaviors to suggest that, salespersons' service interactions depend on their motivation (promotion- or prevention-focused) and their emotional responses during the service encounter. Based on in-depth interviews with salespeople, a questionnaire applying the concepts of 'skeleton' (the core of exchange relations) and 'tissue' (informal social behaviors) was administered to 90 salespeople in apparel stores. Results ...

  8. Interactions between affective and cognitive processing systems in problematic gamblers: a functional connectivity study.

    Directory of Open Access Journals (Sweden)

    Ruth J van Holst

    Full Text Available BACKGROUND: Motivational and cognitive abnormalities are frequently reported in pathological gambling. However, studies simultaneously investigating motivational and cognitive processing in problematic gamblers are lacking, limiting our understanding of the interplay between these systems in problematic gambling. Studies in non-clinical samples indicate that interactions between dorsal "executive" and ventral "affective" processing systems are necessary for adequate responses in various emotive situations. METHODS: We conducted a generalized Psycho-Physiological Interaction (gPPI analysis to assess the influence of affective stimuli on changes in functional connectivity associated with response inhibition in 16 treatment seeking problematic gamblers (PRGs and 15 healthy controls (HCs using an affective Go-NoGo fMRI paradigm including neutral, gambling-related, positive and negative pictures as neutral and affective conditions. RESULTS: Across groups, task performance accuracy during neutral inhibition trials was positively correlated with functional connectivity between the left caudate and the right middle frontal cortex. During inhibition in the gambling condition, only in PRGs accuracy of task performance was positively correlated with functional connectivity within sub-regions of the dorsal executive system. Group interactions showed that during neutral inhibition, HCs exhibited greater functional connectivity between the left caudate and occipital cortex than PRGs. In contrast, during inhibition in the positive condition, PRGs compared to HCs showed greater functional connectivity between the left caudate and occipital cortex. During inhibition trials in the negative condition, a stronger functional connectivity between the left caudate and the right anterior cingulate cortex in PRGs compared to HCs was present. There were no group interactions during inhibition in the gambling condition. CONCLUSIONS: During gamble inhibition PRGs seem to

  9. The Role of Cognitive and Affective Empathy in Spouses' Support Interactions: An Observational Study.

    Science.gov (United States)

    Verhofstadt, Lesley; Devoldre, Inge; Buysse, Ann; Stevens, Michael; Hinnekens, Céline; Ickes, William; Davis, Mark

    2016-01-01

    The present study examined how support providers' empathic dispositions (dispositional perspective taking, empathic concern, and personal distress) as well as their situational empathic reactions (interaction-based perspective taking, empathic concern, and personal distress) relate to the provision of spousal support during observed support interactions. Forty-five committed couples provided questionnaire data and participated in two ten-minute social support interactions designed to assess behaviors when partners are offering and soliciting social support. A video-review task was used to assess situational forms of perspective taking (e.g., empathic accuracy), empathic concern and personal distress. Data were analyzed by means of the multi-level Actor-Partner Interdependence Model. Results revealed that providers scoring higher on affective empathy (i.e., dispositional empathic concern), provided lower levels of negative support. In addition, for male partners, scoring higher on cognitive empathy (i.e., situational perspective taking) was related to lower levels of negative support provision. For both partners, higher scores on cognitive empathy (i.e., situational perspective taking) correlated with more instrumental support provision. Male providers scoring higher on affective empathy (i.e., situational personal distress) provided higher levels of instrumental support. Dispositional perspective taking was related to higher scores on emotional support provision for male providers. The current study furthers our insight into the empathy-support link, by revealing differential effects (a) for men and women, (b) of both cognitive and affective empathy, and

  10. The Role of Cognitive and Affective Empathy in Spouses' Support Interactions: An Observational Study.

    Directory of Open Access Journals (Sweden)

    Lesley Verhofstadt

    Full Text Available The present study examined how support providers' empathic dispositions (dispositional perspective taking, empathic concern, and personal distress as well as their situational empathic reactions (interaction-based perspective taking, empathic concern, and personal distress relate to the provision of spousal support during observed support interactions. Forty-five committed couples provided questionnaire data and participated in two ten-minute social support interactions designed to assess behaviors when partners are offering and soliciting social support. A video-review task was used to assess situational forms of perspective taking (e.g., empathic accuracy, empathic concern and personal distress. Data were analyzed by means of the multi-level Actor-Partner Interdependence Model. Results revealed that providers scoring higher on affective empathy (i.e., dispositional empathic concern, provided lower levels of negative support. In addition, for male partners, scoring higher on cognitive empathy (i.e., situational perspective taking was related to lower levels of negative support provision. For both partners, higher scores on cognitive empathy (i.e., situational perspective taking correlated with more instrumental support provision. Male providers scoring higher on affective empathy (i.e., situational personal distress provided higher levels of instrumental support. Dispositional perspective taking was related to higher scores on emotional support provision for male providers. The current study furthers our insight into the empathy-support link, by revealing differential effects (a for men and women, (b of both cognitive and affective empathy, and

  11. Spatial heterogeneity of plant-soil feedback affects root interactions and interspecific competition.

    Science.gov (United States)

    Hendriks, Marloes; Ravenek, Janneke M; Smit-Tiekstra, Annemiek E; van der Paauw, Jan Willem; de Caluwe, Hannie; van der Putten, Wim H; de Kroon, Hans; Mommer, Liesje

    2015-08-01

    Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species. We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR. All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment. We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands.

  12. Relative abundance of an invasive alien plant affects insect-flower interaction networks in Ireland

    Science.gov (United States)

    Stout, Jane C.; Casey, Leanne M.

    2014-02-01

    Invasive alien flowering plants may affect native plant pollinator interactions and have knock on impacts on populations of native plants and animals. The magnitude of these impacts, however, may be modified by the relative abundance of the invasive plant and the number of flowers it presents.We tested this by examining the structure of insect-flower interaction networks in six sites with increasing levels of invasion by Rhododendron ponticum in Ireland.Neither flower-visiting insect abundance, species richness nor diversity were related to R. ponticum flower abundance, but the composition of insect communities was. The total number of flowers in a site increased with the relative abundance of R. ponticum flowers but the number of co-flowering native plant species in these sites was low (<6), making interaction networks relatively small.As a result, changes in interaction network properties (connectance, interaction evenness and network level specialisation), which correlated with R. ponticum flower abundance, were a result of the small network size rather than due to changes in the resilience of networks.Overall, we conclude that the impacts of invasive alien plants on native plant-pollinator interactions are not only species specific, but site specific, according to the abundance of flowers produced by both the invasive and the native plants.

  13. The Interactive Effects of Affect Lability, Negative Urgency, and Sensation Seeking on Young Adult Problematic Drinking

    Directory of Open Access Journals (Sweden)

    Kenny Karyadi

    2013-01-01

    Full Text Available Prior studies have suggested that affect lability might reduce the risk for problematic drinking among sensation seekers by compensating for their deficiencies in emotional reactivity and among individuals high on negative urgency by disrupting stable negative emotions. Due to the high prevalence of college drinking, this study examined whether affect lability interacted with sensation seeking and negative urgency to influence college student problematic drinking. 414 college drinkers (mean age: 20, 77% female, and 74% Caucasian from a US Midwestern University completed self-administered questionnaires online. Consistent with our hypotheses, our results indicated that the effects of sensation seeking and negative urgency on problematic drinking weakened at higher levels of affect lability. These findings emphasize the importance of considering specific emotional contexts in understanding how negative urgency and sensation seeking create risk for problematic drinking among college students. These findings might also help us better understand how to reduce problematic drinking among sensation seekers and individuals high on negative urgency.

  14. "God of Small Things": Service Interaction's Roots in Regulatory Focus and Affectivity

    Directory of Open Access Journals (Sweden)

    Tali Seger-Guttmann

    2014-06-01

    Full Text Available We link regulatory focus, positive and negative affective states, and service behaviors to suggest that, salespersons' service interactions depend on their motivation (promotion- or prevention-focused and their emotional responses during the service encounter. Based on in-depth interviews with salespeople, a questionnaire applying the concepts of 'skeleton' (the core of exchange relations and 'tissue' (informal social behaviors was administered to 90 salespeople in apparel stores. Results supported our main assumption that salespeople interact with customers based on their regulatory focus (Promotion and Prevention and affectivity (PA and NA. Promotion focus was positively related to positive tissue behaviors (i.e., extra-role behaviors and to positive affect (PA and negatively related to negative affect (NA. Promotion-focused salespeople are more likely to demonstrate PA and high-quality service performance by adopting extra-role (tissue behaviors. PA and NA fully mediated the relationship between promotion focus and positive tissue behaviors I. Prevention focus was found to be positively correlated with skeleton behaviors (i.e., core behaviors and NA. No relationship was found between prevention focus and PA.

  15. Lamins, laminopathies and disease mechanisms: Possible role for proteasomal degradation of key regulatory proteins

    Indian Academy of Sciences (India)

    Veena K Parnaik; Pankaj Chaturvedi; B H Muralikrishna

    2011-08-01

    Lamins are major structural proteins of the nucleus and are essential for nuclear integrity and organization of nuclear functions. Mutations in the human lamin genes lead to highly degenerative genetic diseases that affect a number of different tissues such as muscle, adipose or neuronal tissues, or cause premature ageing syndromes. New findings on the role of lamins in cellular signalling pathways, as well as in ubiquitin-mediated proteasomal degradation, have given important insights into possible mechanisms of pathogenesis.

  16. Lysine Ubiquitination and Acetylation of Human Cardiac 20S Proteasomes

    Science.gov (United States)

    Lau, Edward; Choi, Howard JH; Ng, Dominic CM; Meyer, David; Fang, Caiyun; Li, Haomin; Wang, Ding; Zelaya, Ivette M; Yates, John R; Lam, Maggie PY

    2016-01-01

    Purpose Altered proteasome functions are associated with multiple cardiomyopathies. While the proteasome targets poly-ubiquitinated proteins for destruction, it itself is modifiable by ubiquitination. We aim to identify the exact ubiquitination sites on cardiac proteasomes and examine whether they are also subject to acetylations. Experimental design Assembled cardiac 20S proteasome complexes were purified from five human hearts with ischemic cardiomyopathy, then analyzed by high-resolution MS to identify ubiquitination and acetylation sites. We developed a library search strategy that may be used to complement database search in identifying PTM in different samples. Results We identified 63 ubiquitinated lysines from intact human cardiac 20S proteasomes. In parallel, 65 acetylated residues were also discovered, 39 of which shared with ubiquitination sites. Conclusion and clinical relevance This is the most comprehensive characterization of cardiac proteasome ubiquitination to-date. There are significant overlaps between the discovered ubiquitination and acetylation sites, permitting potential crosstalk in regulating proteasome functions. The information presented here will aid future therapeutic strategies aimed at regulating the functions of cardiac proteasomes. PMID:24957502

  17. How the ubiquitin proteasome system regulates the regulators of transcription.

    Science.gov (United States)

    Ee, Gary; Lehming, Norbert

    2012-01-01

    The ubiquitin proteasome system plays an important role in transcription. Monoubiquitination of activators is believed to aid their function, while the 26S proteasomal degradation of repressors is believed to restrict their function. What remains controversial is the question of whether the degradation of activators aids or restricts their function.

  18. Predicting proteasomal cleavage sites: a comparison of available methods

    DEFF Research Database (Denmark)

    Saxova, P.; Buus, S.; Brunak, Søren;

    2003-01-01

    The proteasome plays an essential role in the immune responses of vertebrates. By degrading intercellular proteins from self and non-self, the proteasome produces the majority of the peptides that are presented to cytotoxic T cells (CTL). There is accumulating evidence that the C-terminal, in par...

  19. An atomic model AAA-ATPase/20S core particle sub-complex of the 26S proteasome.

    Science.gov (United States)

    Förster, Friedrich; Lasker, Keren; Beck, Florian; Nickell, Stephan; Sali, Andrej; Baumeister, Wolfgang

    2009-10-16

    The 26S proteasome is the most downstream element of the ubiquitin-proteasome pathway of protein degradation. It is composed of the 20S core particle (CP) and the 19S regulatory particle (RP). The RP consists of 6 AAA-ATPases and at least 13 non-ATPase subunits. Based on a cryo-EM map of the 26S proteasome, structures of homologs, and physical protein-protein interactions we derive an atomic model of the AAA-ATPase-CP sub-complex. The ATPase order in our model (Rpt1/Rpt2/Rpt6/Rpt3/Rpt4/Rpt5) is in excellent agreement with the recently identified base-precursor complexes formed during the assembly of the RP. Furthermore, the atomic CP-AAA-ATPase model suggests that the assembly chaperone Nas6 facilitates CP-RP association by enhancing the shape complementarity between Rpt3 and its binding CP alpha subunits partners.

  20. An atomic model AAA-ATPase/20S core particle sub-complex of the 26S proteasome

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Friedrich [Department of Structural Biology, Max-Planck-Institute of Biochemistry, D-82152 Martinsried (Germany); Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences (QB3), University of California at San Francisco, San Francisco (United States); Lasker, Keren [Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences (QB3), University of California at San Francisco, San Francisco (United States); Blavatnik School of Computer Science, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv (Israel); Beck, Florian; Nickell, Stephan [Department of Structural Biology, Max-Planck-Institute of Biochemistry, D-82152 Martinsried (Germany); Sali, Andrej [Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences (QB3), University of California at San Francisco, San Francisco (United States); Baumeister, Wolfgang, E-mail: baumeist@biochem.mpg.de [Department of Structural Biology, Max-Planck-Institute of Biochemistry, D-82152 Martinsried (Germany)

    2009-10-16

    The 26S proteasome is the most downstream element of the ubiquitin-proteasome pathway of protein degradation. It is composed of the 20S core particle (CP) and the 19S regulatory particle (RP). The RP consists of 6 AAA-ATPases and at least 13 non-ATPase subunits. Based on a cryo-EM map of the 26S proteasome, structures of homologs, and physical protein-protein interactions we derive an atomic model of the AAA-ATPase-CP sub-complex. The ATPase order in our model (Rpt1/Rpt2/Rpt6/Rpt3/Rpt4/Rpt5) is in excellent agreement with the recently identified base-precursor complexes formed during the assembly of the RP. Furthermore, the atomic CP-AAA-ATPase model suggests that the assembly chaperone Nas6 facilitates CP-RP association by enhancing the shape complementarity between Rpt3 and its binding CP alpha subunits partners.

  1. Sorption interactions of organic compounds with soils affected by agricultural olive mill wastewater.

    Science.gov (United States)

    Keren, Yonatan; Borisover, Mikhail; Bukhanovsky, Nadezhda

    2015-11-01

    The organic compound-soil interactions may be strongly influenced by changes in soil organic matter (OM) which affects the environmental fate of multiple organic pollutants. The soil OM changes may be caused by land disposal of various OM-containing wastes. One unique type of OM-rich waste is olive mill-related wastewater (OMW) characterized by high levels of OM, the presence of fatty aliphatics and polyphenolic aromatics. The systematic data on effects of the land-applied OMW on organic compound-soil interactions is lacking. Therefore, aqueous sorption of simazine and diuron, two herbicides, was examined in batch experiments onto three soils, including untreated and OMW-affected samples. Typically, the organic compound-soil interactions increased following the prior land application of OMW. This increase is associated with the changes in sorption mechanisms and cannot be attributed solely to the increase in soil organic carbon content. A novel observation is that the OMW application changes the soil-sorbent matrix in such a way that the solute uptake may become cooperative or the existing ability of a soil sorbent to cooperatively sorb organic molecules from water may become characterized by a larger affinity. The remarkable finding of this study was that in some cases a cooperative uptake of organic molecules by soils makes itself evident in distinct sigmoidal sorption isotherms rarely observed in soil sorption of non-ionized organic compounds; the cooperative herbicide-soil interactions may be characterized by the Hill model coefficients. However, no single trend was found for the effect of applied OMW on the mechanisms of organic compound-soil interactions. PMID:26183941

  2. Motion and emotion: depression reduces psychomotor performance and alters affective movements in caregiving interactions

    Directory of Open Access Journals (Sweden)

    Katherine S Young

    2015-02-01

    Full Text Available Background: Impaired social functioning is a well-established feature of depression. Evidence to date suggests that disrupted processing of emotional cues may constitute part of this impairment. Beyond processing of emotional cues, fluent social interactions require that people physically move in synchronised, contingent ways. Disruptions to physical movements are a diagnostic feature of depression (psychomotor disturbance but have not previously been assessed in the context of social functioning. Here we investigated the impact of psychomotor disturbance in depression on physical responsive behaviour in both an experimental and observational setting.Methods: In Experiment 1, we examined motor disturbance in depression in response to salient emotional sounds, using a laboratory-based effortful motor task. In Experiment 2, we explored whether psychomotor disturbance was apparent in real-life social interactions. Using mother-infant interactions as a model affective social situation, we compared physical behaviours of mothers with and without postnatal depression (PND.Results: We found impairments in precise, controlled psychomotor performance in adults with depression relative to healthy adults (Experiment 1. Despite this disruption, all adults showed enhanced performance following exposure to highly salient emotional cues (infant cries. Examining real-life interactions, we found differences in physical movements, namely reduced affective touching, in mothers with PND responding to their infants, compared to healthy mothers (Experiment 2.Conclusions: Together, these findings suggest that psychomotor disturbance may be an important feature of depression that can impair social functioning. Future work investigating whether improvements in physical movement in depression could have a positive impact on social interactions would be of much interest.

  3. Using Bayesian Nonparametric Hidden Semi-Markov Models to Disentangle Affect Processes during Marital Interaction.

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    William A Griffin

    Full Text Available Sequential affect dynamics generated during the interaction of intimate dyads, such as married couples, are associated with a cascade of effects-some good and some bad-on each partner, close family members, and other social contacts. Although the effects are well documented, the probabilistic structures associated with micro-social processes connected to the varied outcomes remain enigmatic. Using extant data we developed a method of classifying and subsequently generating couple dynamics using a Hierarchical Dirichlet Process Hidden semi-Markov Model (HDP-HSMM. Our findings indicate that several key aspects of existing models of marital interaction are inadequate: affect state emissions and their durations, along with the expected variability differences between distressed and nondistressed couples are present but highly nuanced; and most surprisingly, heterogeneity among highly satisfied couples necessitate that they be divided into subgroups. We review how this unsupervised learning technique generates plausible dyadic sequences that are sensitive to relationship quality and provide a natural mechanism for computational models of behavioral and affective micro-social processes.

  4. Using Bayesian Nonparametric Hidden Semi-Markov Models to Disentangle Affect Processes during Marital Interaction.

    Science.gov (United States)

    Griffin, William A; Li, Xun

    2016-01-01

    Sequential affect dynamics generated during the interaction of intimate dyads, such as married couples, are associated with a cascade of effects-some good and some bad-on each partner, close family members, and other social contacts. Although the effects are well documented, the probabilistic structures associated with micro-social processes connected to the varied outcomes remain enigmatic. Using extant data we developed a method of classifying and subsequently generating couple dynamics using a Hierarchical Dirichlet Process Hidden semi-Markov Model (HDP-HSMM). Our findings indicate that several key aspects of existing models of marital interaction are inadequate: affect state emissions and their durations, along with the expected variability differences between distressed and nondistressed couples are present but highly nuanced; and most surprisingly, heterogeneity among highly satisfied couples necessitate that they be divided into subgroups. We review how this unsupervised learning technique generates plausible dyadic sequences that are sensitive to relationship quality and provide a natural mechanism for computational models of behavioral and affective micro-social processes. PMID:27187319

  5. Using Bayesian Nonparametric Hidden Semi-Markov Models to Disentangle Affect Processes during Marital Interaction

    Science.gov (United States)

    Griffin, William A.; Li, Xun

    2016-01-01

    Sequential affect dynamics generated during the interaction of intimate dyads, such as married couples, are associated with a cascade of effects—some good and some bad—on each partner, close family members, and other social contacts. Although the effects are well documented, the probabilistic structures associated with micro-social processes connected to the varied outcomes remain enigmatic. Using extant data we developed a method of classifying and subsequently generating couple dynamics using a Hierarchical Dirichlet Process Hidden semi-Markov Model (HDP-HSMM). Our findings indicate that several key aspects of existing models of marital interaction are inadequate: affect state emissions and their durations, along with the expected variability differences between distressed and nondistressed couples are present but highly nuanced; and most surprisingly, heterogeneity among highly satisfied couples necessitate that they be divided into subgroups. We review how this unsupervised learning technique generates plausible dyadic sequences that are sensitive to relationship quality and provide a natural mechanism for computational models of behavioral and affective micro-social processes. PMID:27187319

  6. Mathematics for Maths Anxious Tertiary Students: Integrating the cognitive and affective domains using interactive multimedia

    Directory of Open Access Journals (Sweden)

    Janet Taylor

    2011-04-01

    Full Text Available Today, commencing university students come from a diversity of backgrounds and have a broad range of abilities and attitudes. It is well known that attitudes towards mathematics, especially mathematics anxiety, can affect students’ performance to the extent that mathematics is often seen as a barrier to success by many. This paper reports on the design, development and evaluation of an interactive multimedia resource designed to explicitly address students’ beliefs and attitudes towards mathematics by following five characters as they progress through the highs and low of studying a preparatory mathematics course. The resource was built within two theoretical frameworks, one related to effective numeracy teaching (Marr and Helme 1991 and the other related to effective educational technology development (Laurillard 2002. Further, it uses a number of multimedia alternatives (video, audio, animations, diarying, interactive examples and self assessment to encourage students to feel part of a group, to reflect on their feelings and beliefs about mathematics, to expose students to authentic problem solving and generally build confidence through practice and self-assessment. Evaluation of the resource indicated that it encouraged students to value their own mathematical ability and helped to build confidence, while developing mathematical problem solving skills. The evaluation clearly demonstrated that it is possible to address the affective domain through multimedia initiatives and that this can complement the current focus on computer mediated communication as the primary method of addressing affective goals within the online environment.

  7. Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

    Science.gov (United States)

    Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

    2015-12-01

    Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

  8. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    Science.gov (United States)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-07-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services.

  9. AFFECTIVE AND EMOTIONAL ASPECTS OF HUMAN-COMPUTER INTERACTION: Game-Based and Innovative Learning Approaches

    Directory of Open Access Journals (Sweden)

    A. Askim GULUMBAY, Anadolu University, TURKEY

    2006-07-01

    Full Text Available This book was edited by, Maja Pivec, an educator at the University of Applied Sciences, and published by IOS Pres in 2006. The learning process can be seen as an emotional and personal experience that is addictive and leads learners to proactive behavior. New research methods in this field are related to affective and emotional approaches to computersupported learning and human-computer interactions.Bringing together scientists and research aspects from psychology, educational sciences, cognitive sciences, various aspects of communication and human computer interaction, interface design andcomputer science on one hand and educators and game industry on the other, this should open gates to evolutionary changes of the learning industry. The major topics discussed are emotions, motivation, games and game-experience.

  10. Indirect trophic interactions with an invasive species affect phenotypic divergence in a top consumer.

    Science.gov (United States)

    Hirsch, P E; Eklöv, P; Svanbäck, R

    2013-05-01

    While phenotypic responses to direct species interactions are well studied, we know little about the consequences of indirect interactions for phenotypic divergence. In this study we used lakes with and without the zebra mussel to investigate effects of indirect trophic interactions on phenotypic divergence between littoral and pelagic perch. We found a greater phenotypic divergence between littoral and pelagic individuals in lakes with zebra mussels and propose a mussel-mediated increase in pelagic and benthic resource availability as a major factor underlying this divergence. Lakes with zebra mussels contained higher densities of large plankton taxa and large invertebrates. We suggest that this augmented resource availability improved perch foraging opportunities in both the littoral and pelagic zones. Perch in both habitats could hence express a more specialized foraging morphology, leading to an increased divergence of perch forms in lakes with zebra mussels. As perch do not prey on mussels directly, we conclude that the increased divergence results from indirect interactions with the mussels. Our results hence suggest that species at lower food web levels can indirectly affect phenotypic divergence in species at the top of the food chain. PMID:23463242

  11. Interaction among the Criteria Affecting Main Battle Tank Selection: An Analysis with DEMATEL Method

    Directory of Open Access Journals (Sweden)

    Yavuz Gazibey

    2015-09-01

    Full Text Available Main battle tanks (MBTs have always been in the heart of all military campaigns and have enabled armies to fight across the full spectrum of war. Countries need to consider the complex interactions between subsystems of MBTs in the decision phase of a design process or MBT acquisition. In order to define the interaction among the subsystems of ‘system of systems’, which is MBT system for this case, this study aims to determine the criteria and their sub criteria affecting MBT selection problem and to analyse the cause and effect relations among these criteria. The criteria and the complex interaction among them have been determined by consulting a group of experts. Because of multiple complex criteria interactions in MBT selection problem, decision making trial and evaluation laboratory (DEMATEL method is used as a multiple criteria decision making method. DEMATEL method is applied on the main and the sub criteria separately to understand the cause and effect relations. The results show that Survivability main criterion has the strongest central role among the main criteria for MBT selection, while the followers are firepower, mobility and command and control (C2. It is also shown that, in terms of sub criteria for MBT selection, ballistic protection, a sub criterion of survivability main criterion, has the highest degree of influence over most of the other sub criteria. However, physical dimensions/silhouette, another sub criterion of survivability, is the most affected sub criteria. The top five sub criteria in terms of central role are determined as physical dimensions/silhouette, ballistic protection, power/weight ratio, ground pressure and suspension system.

  12. Structure of the 26S proteasome from Schizosaccharomyces pombe at subnanometer resolution.

    Science.gov (United States)

    Bohn, Stefan; Beck, Florian; Sakata, Eri; Walzthoeni, Thomas; Beck, Martin; Aebersold, Ruedi; Förster, Friedrich; Baumeister, Wolfgang; Nickell, Stephan

    2010-12-01

    The structure of the 26S proteasome from Schizosaccharomyces pombe has been determined to a resolution of 9.1 Å by cryoelectron microscopy and single particle analysis. In addition, chemical cross-linking in conjunction with mass spectrometry has been used to identify numerous residue pairs in close proximity to each other, providing an array of spatial restraints. Taken together these data clarify the topology of the AAA-ATPase module in the 19S regulatory particle and its spatial relationship to the α-ring of the 20S core particle. Image classification and variance analysis reveal a belt of high "activity" surrounding the AAA-ATPase module which is tentatively assigned to the reversible association of proteasome interacting proteins and the conformational heterogeneity among the particles. An integrated model is presented which sheds light on the early steps of protein degradation by the 26S complex.

  13. Discovery of new [Formula: see text] proteasome inhibitors using a knowledge-based computational screening approach.

    Science.gov (United States)

    Mehra, Rukmankesh; Chib, Reena; Munagala, Gurunadham; Yempalla, Kushalava Reddy; Khan, Inshad Ali; Singh, Parvinder Pal; Khan, Farrah Gul; Nargotra, Amit

    2015-11-01

    Mycobacterium tuberculosis bacteria cause deadly infections in patients [Corrected]. The rise of multidrug resistance associated with tuberculosis further makes the situation worse in treating the disease. M. tuberculosis proteasome is necessary for the pathogenesis of the bacterium validated as an anti-tubercular target, thus making it an attractive enzyme for designing Mtb inhibitors. In this study, a computational screening approach was applied to identify new proteasome inhibitor candidates from a library of 50,000 compounds. This chemical library was procured from the ChemBridge (20,000 compounds) and the ChemDiv (30,000 compounds) databases. After a detailed analysis of the computational screening results, 50 in silico hits were retrieved and tested in vitro finding 15 compounds with [Formula: see text] values ranging from 35.32 to 64.15 [Formula: see text]M on lysate. A structural analysis of these hits revealed that 14 of these compounds probably have non-covalent mode of binding to the target and have not reported for anti-tubercular or anti-proteasome activity. The binding interactions of all the 14 protein-inhibitor complexes were analyzed using molecular docking studies. Further, molecular dynamics simulations of the protein in complex with the two most promising hits were carried out so as to identify the key interactions and validate the structural stability.

  14. Proteasome activation as a novel anti-aging strategy.

    Science.gov (United States)

    Gonos, Efstathios

    2014-10-01

    Aging and longevity are two multifactorial biological phenomena whose knowledge at molecular level is still limited. We have studied proteasome function in replicative senescence and cell survival (Mol Aspects Med 35, 1-71, 2014). We have observed reduced levels of proteasome content and activities in senescent cells due to the down-regulation of the catalytic subunits of the 20S complex (J Biol Chem 278, 28026-28037, 2003). In support, partial inhibition of proteasomes in young cells by specific inhibitors induces premature senescence which is p53 dependent (Aging Cell 7, 717-732, 2008). Stable over-expression of catalytic subunits or POMP resulted in enhanced proteasome assembly and activities and increased cell survival following treatments with various oxidants. Importantly, the developed "proteasome activated" human fibroblasts cell lines exhibit a delay of senescence by approximately 15% (J Biol Chem 280, 11840-11850, 2005; J Biol Chem 284, 30076-30086, 2009). Our current work proposes that proteasome activation is an evolutionary conserved mechanism, as it can delay aging in various in vivo systems. Moreover, additional findings indicate that the recorded proteasome activation by many inducers is Nrf2-dependent (J Biol Chem 285, 8171-8184, 2010). Finally, we have studied the proteolysis processes of various age-related proteins and we have identified that CHIP is a major p53 E3 ligase in senescent fibroblasts (Free Rad Biol Med 50, 157-165, 2011). PMID:26461417

  15. Neural systems supporting cognitive-affective interactions in adolescence: The role of puberty and implications for affective disorders

    Directory of Open Access Journals (Sweden)

    Cecile D. Ladouceur

    2012-08-01

    Full Text Available Evidence from longitudinal studies suggests that adolescence may represent a period of vulnerability that, in the context of adverse events, could contribute to developmental trajectories toward behavioral and emotional health problems, including affective disorders. Adolescence is also a sensitive period for the development of neural systems supporting cognitive-affective processes, which have been implicated in the pathophysiology of affective disorders such as anxiety and mood disorders. In particular, the onset of puberty brings about a cascade of physical, hormonal, psychological, and social changes that contribute in complex ways to the development of these systems. This article provides a brief overview of neuroimaging research pertaining to the development of cognitive-affective processes in adolescence. It also includes a brief review of evidence from animal and human neuroimaging studies suggesting that sex steroids influence the connectivity between prefrontal cortical and subcortical limbic regions in ways that contribute to increased reactivity to emotionally salient stimuli. We integrate these findings in the context of a developmental affective neuroscience framework suggesting that the impact of rising levels of sex steroids during puberty on fronto-limbic connectivity may be even greater in the context of protracted development of prefrontal cortical regions in adolescence. We conclude by discussing the implications of these findings for future research aimed at identifying neurodevelopmental markers of risk for future onset of affective disorders.

  16. Potential role of 20S proteasome in maintaining stem cell integrity of human bone marrow stromal cells in prolonged culture expansion

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Li, E-mail: luli7300@126.com [Department of Anatomy, Shanxi Medical University, Taiyuan 030001 (China); Song, Hui-Fang; Zhang, Wei-Guo; Liu, Xue-Qin; Zhu, Qian; Cheng, Xiao-Long; Yang, Gui-Jiao [Department of Anatomy, Shanxi Medical University, Taiyuan 030001 (China); Li, Ang [Department of Anatomy, University of Hong Kong, Hong Kong Special Administrative Region (Hong Kong); Xiao, Zhi-Cheng, E-mail: zhicheng.xiao@monash.edu [Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical College, Kunming 650031 (China); Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Melbourne 3800 (Australia)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Prolonged culture expansion retards proliferation and induces senescence of hBMSCs. Black-Right-Pointing-Pointer Reduced 20S proteasomal activity and expression potentially contribute to cell aging. Black-Right-Pointing-Pointer MG132-mediated 20S proteasomal inhibition induces senescence-like phenotype. Black-Right-Pointing-Pointer 18{alpha}-GA stimulates proteasomal activity and restores replicative senescence. Black-Right-Pointing-Pointer 18{alpha}-GA retains differentiation without affecting stem cell characterizations. -- Abstract: Human bone marrow stromal cells (hBMSCs) could be used in clinics as precursors of multiple cell lineages following proper induction. Such application is impeded by their characteristically short lifespan, together with the increasing loss of proliferation capability and progressive reduction of differentiation potential after the prolonged culture expansion. In the current study, we addressed the possible role of 20S proteasomes in this process. Consistent with prior reports, long-term in vitro expansion of hBMSCs decreased cell proliferation and increased replicative senescence, accompanied by reduced activity and expression of the catalytic subunits PSMB5 and PSMB1, and the 20S proteasome overall. Application of the proteasome inhibitor MG132 produced a senescence-like phenotype in early passages, whereas treating late-passage cells with 18{alpha}-glycyrrhetinic acid (18{alpha}-GA), an agonist of 20S proteasomes, delayed the senescence progress, enhancing the proliferation and recovering the capability of differentiation. The data demonstrate that activation of 20S proteasomes assists in counteracting replicative senescence of hBMSCs expanded in vitro.

  17. Conserved mosquito/parasite interactions affect development of Plasmodium falciparum in Africa.

    Directory of Open Access Journals (Sweden)

    Antonio M Mendes

    2008-05-01

    Full Text Available In much of sub-Saharan Africa, the mosquito Anopheles gambiae is the main vector of the major human malaria parasite, Plasmodium falciparum. Convenient laboratory studies have identified mosquito genes that affect positively or negatively the developmental cycle of the model rodent parasite, P. berghei. Here, we use transcription profiling and reverse genetics to explore whether five disparate mosquito gene regulators of P. berghei development are also pertinent to A. gambiae/P. falciparum interactions in semi-natural conditions, using field isolates of this parasite and geographically related mosquitoes. We detected broadly similar albeit not identical transcriptional responses of these genes to the two parasite species. Gene silencing established that two genes affect similarly both parasites: infections are hindered by the intracellular local activator of actin cytoskeleton dynamics, WASP, but promoted by the hemolymph lipid transporter, ApoII/I. Since P. berghei is not a natural parasite of A. gambiae, these data suggest that the effects of these genes have not been drastically altered by constant interaction and co-evolution of A. gambiae and P. falciparum; this conclusion allowed us to investigate further the mode of action of these two genes in the laboratory model system using a suite of genetic tools and infection assays. We showed that both genes act at the level of midgut invasion during the parasite's developmental transition from ookinete to oocyst. ApoII/I also affects the early stages of oocyst development. These are the first mosquito genes whose significant effects on P. falciparum field isolates have been established by direct experimentation. Importantly, they validate for semi-field human malaria transmission the concept of parasite antagonists and agonists.

  18. Detection of antibodies to the 20s proteasome by ELISA

    DEFF Research Database (Denmark)

    Jørgensen, Karin Meinike; Frederiksen, Jette Lautrup; Nielsen, Christoffer Tandrup;

    2013-01-01

    The presence of antibodies against the 20S proteasome has been correlated with diseases like multiple sclerosis (MS) and systemic lupus erythematosus (SLE) but no definite association has been established. In order to investigate this further, we optimized an ELISA for proteasome antibodies...... and applied it to test a total of 324 serum and plasma samples from MS patients, SLE patients, and healthy controls. Our results yield a functional and reliable assay but no correlation between the amount of proteasome antibodies present and the development of MS or SLE could be established....

  19. Prediction of proteasome cleavage motifs by neural networks

    DEFF Research Database (Denmark)

    Kesimir, C.; Nussbaum, A.K.; Schild, H.;

    2002-01-01

    We present a predictive method that can simulate an essential step in the antigen presentation in higher vertebrates, namely the step involving the proteasomal degradation of polypeptides into fragments which have the potential to bind to MHC Class I molecules. Proteasomal cleavage prediction...... the prediction of MHC Class I ligand boundaries more accurate: 65% of the cleavage sites and 85% of the non-cleavage sites are correctly determined. Moreover, we show that the neural networks trained on the constitutive proteasome data learns a specificity that differs from that of the networks...

  20. Imaging Imageability: Behavioral Effects and Neural Correlates of Its Interaction with Affect and Context

    Science.gov (United States)

    Westbury, Chris F.; Cribben, Ivor; Cummine, Jacqueline

    2016-01-01

    The construct of imageability refers to the extent to which a word evokes a tangible sensation. Previous research (Westbury et al., 2013) suggests that the behavioral effects attributed to a word's imageability can be largely or wholly explained by two objective constructs, contextual density and estimated affect. Here, we extend these previous findings in two ways. First, we show that closely matched stimuli on the three measures of contextual density, estimated affect, and human-judged imageability show a three-way interaction in explaining variance in LD RTs, but that imagebility accounts for no additional variance after contextual density and estimated affect are entered first. Secondly, we demonstrate that the loci and functional connectivity (via graphical models) of the brain regions implicated in processing the three variables during that task are largely over-lapping and similar. These two lines of evidence support the conclusion that the effect usually attributed to human-judged imageability is largely or entirely due to the effects of other correlated measures that are directly computable. PMID:27471455

  1. Phenological mismatch and ontogenetic diet shifts interactively affect offspring condition in a passerine.

    Science.gov (United States)

    Samplonius, Jelmer M; Kappers, Elena F; Brands, Stef; Both, Christiaan

    2016-09-01

    Climate change may cause phenological asynchrony between trophic levels, which can lead to mismatched reproduction in animals. Although indirect effects of mismatch on fitness are well described, direct effects on parental prey choice are not. Moreover, direct effects of prey variation on offspring condition throughout their early development are understudied. Here, we used camera trap data collected over 2 years to study the effects of trophic mismatch and nestling age on prey choice in pied flycatchers (Ficedula hypoleuca). Furthermore, we studied the effect of mismatch and variation in nestling diet on offspring condition. Both experimentally induced and natural mismatches with the caterpillar peak negatively affected absolute and relative numbers of caterpillars and offspring condition (mass, tarsus and wing length) and positively affected absolute and relative numbers of flying insects in the nestling diet. Feeding more flying insects was negatively correlated with nestling day 12 mass. Both descriptive and experimental data showed preferential feeding of spiders when nestlings were spiders during this phase was positively correlated with tarsus growth. These results highlight the need for a more inclusive framework to study phenological mismatch in nature. The general focus on only one prey type, the rarity of studies that measure environmental abundance of prey, and the lack of timing experiments in dietary studies currently hamper understanding of the actual trophic interactions that affect fitness under climate change. PMID:27263989

  2. Some interactive factors affecting trench-cover integrity on low-level waste sites

    International Nuclear Information System (INIS)

    This paper describes important mechanisms by which radionuclide can be transported from low-level waste disposal sites into biological pathways, discuss interactions of abiotic and biotic processes, and recommends environmental characteristics that should be measured to design sites that minimize this transport. Past experience at shallow land burial sites for low-level radioactive wastes suggest that occurrences of waste exposure and radionuclide transport are often related to inadequate trench cover designs. Meeting performance standards at low-level waste sites can only be achieved by recognizing that physical, chemical, and biological processes operating on and in a trench cover profile are highly interactive. Failure to do so can lead to improper design criteria and subsequent remedial action procedures that can adversely affect site stability. Based upon field experiments and computer modeling, recommendations are made on site characteristics that require measurement in order to design systems that reduce surface runoff and erosion, manage soil moisture and biota in the cover profile to maximize evapotranspiration and minimize percolation, and place bounds on the intrusion potential of plants and animals into the waste material. Major unresolved problems include developing probabilistic approaches that include climatic variability, improved knowledge of soil-water-plant-erosion relationships, development of practical vegetation establishment and maintenance procedures, prediction and quantification of site potential and plant succession, and understanding the interaction of processes occurring on and in the cover profile with deeper subsurface processes

  3. Arabidopsis PROTEASOME REGULATOR1 is required for auxin-mediated suppression of proteasome activity and regulates auxin signalling.

    Science.gov (United States)

    Yang, Bao-Jun; Han, Xin-Xin; Yin, Lin-Lin; Xing, Mei-Qing; Xu, Zhi-Hong; Xue, Hong-Wei

    2016-01-01

    The plant hormone auxin is perceived by the nuclear F-box protein TIR1 receptor family and regulates gene expression through degradation of Aux/IAA transcriptional repressors. Several studies have revealed the importance of the proteasome in auxin signalling, but details on how the proteolytic machinery is regulated and how this relates to degradation of Aux/IAA proteins remains unclear. Here we show that an Arabidopsis homologue of the proteasome inhibitor PI31, which we name PROTEASOME REGULATOR1 (PTRE1), is a positive regulator of the 26S proteasome. Loss-of-function ptre1 mutants are insensitive to auxin-mediated suppression of proteasome activity, show diminished auxin-induced degradation of Aux/IAA proteins and display auxin-related phenotypes. We found that auxin alters the subcellular localization of PTRE1, suggesting this may be part of the mechanism by which it reduces proteasome activity. Based on these results, we propose that auxin regulates proteasome activity via PTRE1 to fine-tune the homoeostasis of Aux/IAA repressor proteins thus modifying auxin activity. PMID:27109828

  4. Major diet-drug interactions affecting the kinetic characteristics and hypolipidaemic properties of statins.

    Science.gov (United States)

    Vaquero, M P; Sánchez Muniz, F J; Jiménez Redondo, S; Prats Oliván, P; Higueras, F J; Bastida, S

    2010-01-01

    Concomitant administration of statins with food may alter statin pharmacokinetics or pharmacodynamics, increasing the risk of adverse reactions such as myopathy or rhabdomyolysis or reducing their pharmacological action. This paper reviews major interactions between statins and dietary compounds. Consumption of pectin or oat bran together with Lovastatin reduces absorption of the drug, while alcohol intake does not appear to affect the efficacy and safety of Fluvastatin treatment. Grapefruit juice components inhibit cytochrome P-4503A4, reducing the presystemic metabolism of drugs such as Simvastatin, Lovastatin and Atorvastatin. Follow-up studies on the therapeutic effect of statins in patients consuming a Mediterranean-style diet are necessary to assure the correct prescription because the oil-statin and minor oil compound-statin possible interactions have been only briefly studied. Preliminary study suggests that olive oil can increase the hypolipaemiant effect of Simvastatin with respect sunflower oil. The consumption of polyunsaturated rich oils, throughout the cytochrome P- 450 activation could decrease the half-life of some statins and therefore their hypolipaemic effects. The statins and n-3 fatty acids combined therapy gives rise to pharmacodinamic interaction that improves the lipid profile and leads greater cardioprotection. Although statins are more effective in high endogenous cholesterol production subjects and plant sterols are more effective in high cholesterol absorption efficacy subjects, plant esterols-statins combined therapy generates very positive complementary effects. This review ends suggesting possible diet-stain interactions that require further investigations (e.g. types of olive oils, fruit juices other than grapefruit, fibre or consumption of alcoholic beverages rich in polyphenols or ethanol).

  5. The Ginkgo biloba Extract EGb 761 Modulates Proteasome Activity and Polyglutamine Protein Aggregation

    Directory of Open Access Journals (Sweden)

    Marcel Stark

    2014-01-01

    Full Text Available The standardized Ginkgo biloba extract EGb 761 has well-described antioxidative activities and effects on different cytoprotective signaling pathways. Consequently, a potential use of EGb 761 in neurodegenerative diseases has been proposed. A common characteristic feature of a variety of such disorders is the pathologic formation of protein aggregates, suggesting a crucial role for protein homeostasis. In this study, we show that EGb 761 increased the catalytic activity of the proteasome and enhanced protein degradation in cultured cells. We further investigated this effect in a cellular model of Huntington’s disease (HD by employing cells expressing pathologic variants of a polyglutamine protein (polyQ protein. We show that EGb 761 affected these cells by (i increasing proteasome activity and (ii inducing a more efficient degradation of aggregation-prone proteins. These results demonstrate a novel activity of EGb 761 on protein aggregates by enhancing proteasomal protein degradation, suggesting a therapeutic use in neurodegenerative disorders with a disturbed protein homeostasis.

  6. Isolation and characterization of a novel endogenous inhibitor of the proteasome

    Energy Technology Data Exchange (ETDEWEB)

    Xiaochong Li (New York Medical Coll., Valhalla (United States) State Univ. of New York, Brooklyn (United States)); Gu, M.; Etlinger, J.D. (New York Medical Coll., Valhalla (United States))

    1991-10-08

    A novel endogenous inhibitor of the proteasome (high molecular weight multicatalytic protease) has been isolated and characterized from human erythrocytes. After purification by ion-exchange and sizing chromatography, the inhibitor displayed a native molecular mass of approximately 200 kDa and contained a single subunit of 50 kDa with an isoelectric point of 6.9. Although the inhibitor noncompetitively blocks proteolysis of (methyl-{sup 14}C)-{alpha}-casein and inhibits hydrolysis of Suc-Leu-Leu-Val-Tyr-AMC, it did not affect hydrolysis of other peptide substrates, such as MeOSuc-Phe-Leu-Phe-MNA and Z-Ala-Arg-Arg-MNA. To further characterize the 50-kDa inhibitor, a monoclonal antibody (MI-8) was generated that showed specific binding upon Western blot analysis of both native PAGE and SDS-PAGE. Immunoprecipitation with MI-8 specifically removed inhibitor activity against the proteasome. The 50-kDa inhibitor is distinct from a previously described 40-kDa inhibitor of the proteasome on the basis of lack of cross-reactivity with MI-8 and dissimilar peptide digest patterns. It is suggested that these endogenous inhibitors may have a role in ATP/ubiquitin-dependent proteolysis and/or other cellular functions involving this protease.

  7. The effects of proteasome inhibitor lactacystin on mouse oocyte meiosis and first cleavage

    Institute of Scientific and Technical Information of China (English)

    TAN; Xin; PENG; An; WANG; Yongchao; TANG; Zuoqing

    2005-01-01

    In order to study the effects of ubiquitin-proteasome pathway (UPP) on mouse oocyte meiosis and cleavage, oocytes undergoing maturation and parthenogenetic activation and 1-cell embryos were treated with lactacystin, a specific inhibitor of proteasome. The results indicared that the rate of GVBD was not influenced by the treatment, but polar body extrusion, parthenogenesis and first cleavage were inhibited. Immunofluorescent staining using anti β-tubulin antibody indicated that the continuous treatment of lactacystin from GV stage disorganized microtubules and spindle assembly. When metaphase stage oocytes were treated with the drug,the already formed spindle structure was not affected, but the oocytes were arrested at metaphases. The 1-cell embryos were arrested at interphase or metaphase of first mitosis when they were incubated in the drug. Proteasome regulatory subunit PA700 was located in the spindle region, as indicated by immunofluorescence. These results suggest that UPP has effects on the process of oocyte meiosis and early cleavage in many aspects, including normal organization of spindle at prophase and segregation of chromosomes at anaphase for normal meiosis.

  8. MiR-200c regulates Noxa expression and sensitivity to proteasomal inhibitors.

    Directory of Open Access Journals (Sweden)

    Mikael Lerner

    Full Text Available The pro-apoptotic p53 target Noxa is a BH3-only protein that antagonizes the function of selected anti-apoptotic Bcl-2 family members. While much is known regarding the transcriptional regulation of Noxa, its posttranscriptional regulation remains relatively unstudied. In this study, we therefore investigated whether Noxa is regulated by microRNAs. Using a screen combining luciferase reporters, bioinformatic target prediction analysis and microRNA expression profiling, we identified miR-200c as a negative regulator of Noxa expression. MiR-200c was shown to repress basal expression of Noxa, as well as Noxa expression induced by various stimuli, including proteasomal inhibition. Luciferase reporter experiments furthermore defined one miR-200c target site in the Noxa 3'UTR that is essential for this direct regulation. In spite of the miR-200c:Noxa interaction, miR-200c overexpression led to increased sensitivity to the clinically used proteasomal inhibitor bortezomib in several cell lines. This apparently contradictory finding was reconciled by the fact that in cells devoid of Noxa expression, miR-200c overexpression had an even more pronounced positive effect on apoptosis induced by proteasomal inhibition. Together, our data define miR-200c as a potentiator of bortezomib-induced cell death. At the same time, we show that miR-200c is a novel negative regulator of the pro-apoptotic Bcl-2 family member Noxa.

  9. Reciprocal regulation of cilia and autophagy via the MTOR and proteasome pathways.

    Science.gov (United States)

    Wang, Shixuan; Livingston, Man J; Su, Yunchao; Dong, Zheng

    2015-04-01

    Primary cilium is an organelle that plays significant roles in a number of cellular functions ranging from cell mechanosensation, proliferation, and differentiation to apoptosis. Autophagy is an evolutionarily conserved cellular function in biology and indispensable for cellular homeostasis. Both cilia and autophagy have been linked to different types of genetic and acquired human diseases. Their interaction has been suggested very recently, but the underlying mechanisms are still not fully understood. We examined autophagy in cells with suppressed cilia and measured cilium length in autophagy-activated or -suppressed cells. It was found that autophagy was repressed in cells with short cilia. Further investigation showed that MTOR activation was enhanced in cilia-suppressed cells and the MTOR inhibitor rapamycin could largely reverse autophagy suppression. In human kidney proximal tubular cells (HK2), autophagy induction was associated with cilium elongation. Conversely, autophagy inhibition by 3-methyladenine (3-MA) and chloroquine (CQ) as well as bafilomycin A1 (Baf) led to short cilia. Cilia were also shorter in cultured atg5-knockout (KO) cells and in atg7-KO kidney proximal tubular cells in mice. MG132, an inhibitor of the proteasome, could significantly restore cilium length in atg5-KO cells, being concomitant with the proteasome activity. Together, the results suggest that cilia and autophagy regulate reciprocally through the MTOR signaling pathway and ubiquitin-proteasome system.

  10. Integrated analysis of microarray data of atherosclerotic plaques: modulation of the ubiquitin-proteasome system.

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    Full Text Available Atherosclerosis is a typical complex multi-factorial disease and many molecules at different levels and pathways were involved in its development. Some studies have investigated the dysregulation in atherosclerosis at mRNA, miRNA or DNA methylation level, respectively. However, to our knowledge, the studies that integrated these data and revealed the abnormal networks of atherosclerosis have not been reported. Using microarray technology, we analyzed the omics data in atherosclerosis at mRNA, miRNA and DNA methylation levels. Our results demonstrated that the global DNA methylation and expression of miRNA/mRNA were significantly decreased in atherosclerotic plaque than in normal vascular tissue. The interaction network constructed using the integrative data revealed many genes, cellular processes and signaling pathways which were widely considered to play crucial roles in atherosclerosis and also revealed some genes, miRNAs or signaling pathways which have not been investigated in atherosclerosis until now (e.g. miR-519d and SNTB2. Moreover, the overall protein ubiquitination in atherosclerotic plaque was significantly increased. The proteasome activity was increased early but decreased in advanced atherosclerosis. Our study revealed many classic and novel genes and miRNAs involved in atherosclerosis and indicated the effects of ubiquitin-proteasome system on atherosclerosis might be closely related to the course of atherosclerosis. However, the efficacy of proteasome inhibitors in the treatment of atherosclerosis still needs more research.

  11. Yeast Pah1p phosphatidate phosphatase is regulated by proteasome-mediated degradation.

    Science.gov (United States)

    Pascual, Florencia; Hsieh, Lu-Sheng; Soto-Cardalda, Aníbal; Carman, George M

    2014-04-01

    Yeast PAH1-encoded phosphatidate phosphatase is the enzyme responsible for the production of the diacylglycerol used for the synthesis of triacylglycerol that accumulates in the stationary phase of growth. Paradoxically, the growth phase-mediated inductions of PAH1 and phosphatidate phosphatase activity do not correlate with the amount of Pah1p; enzyme abundance declined in a growth phase-dependent manner. Pah1p from exponential phase cells was a relatively stable protein, and its abundance was not affected by incubation with an extract from stationary phase cells. Recombinant Pah1p was degraded upon incubation with the 100,000 × g pellet fraction of stationary phase cells, although the enzyme was stable when incubated with the same fraction of exponential phase cells. MG132, an inhibitor of proteasome function, prevented degradation of the recombinant enzyme. Endogenously expressed and plasmid-mediated overexpressed levels of Pah1p were more abundant in the stationary phase of cells treated with MG132. Pah1p was stabilized in mutants with impaired proteasome (rpn4Δ, blm10Δ, ump1Δ, and pre1 pre2) and ubiquitination (hrd1Δ, ubc4Δ, ubc7Δ, ubc8Δ, and doa4Δ) functions. The pre1 pre2 mutations that eliminate nearly all chymotrypsin-like activity of the 20 S proteasome had the greatest stabilizing effect on enzyme levels. Taken together, these results supported the conclusion that Pah1p is subject to proteasome-mediated degradation in the stationary phase. That Pah1p abundance was stabilized in pah1Δ mutant cells expressing catalytically inactive forms of Pah1p and dgk1Δ mutant cells with induced expression of DGK1-encoded diacylglycerol kinase indicated that alteration in phosphatidate and/or diacylglycerol levels might be the signal that triggers Pah1p degradation.

  12. Antitumorigenic effect of proteasome inhibitors on insulinoma cells

    DEFF Research Database (Denmark)

    Størling, Joachim; Allaman-Pillet, Nathalie; Karlsen, Allan E;

    2004-01-01

    Malignant insulinoma is a critical cancer form with a poor prognosis. Because cure by surgery is infrequent, effective chemotherapy is in demand. Induction of cell death in tumor cells by proteasome inhibitors is emerging as a potential strategy in cancer therapy. Here we investigated whether...... inhibition reduced insulin secretion but had no impact on cell viability and even partially protected against the toxic effect of proinflammatory cytokines. Our findings demonstrate that proteasome inhibitors possess antitumorigenic and antiinsulinogenic effects on insulinoma cells....... inhibition of the proteasome has an antitumorigenic potential in insulinoma cells. Exposure of mouse betaTC3 insulinoma cells to the proteasome inhibitor N-Acetyl-Leu-Leu-Nle-CHO (ALLN) reduced cell viability, activated caspase-3, induced apoptosis, and suppressed insulin release. Treatment with ALLN also...

  13. Does prey community composition affect the way different behavioral types interact with their environment?

    Science.gov (United States)

    Nannini, Michael A; Wahl, David H

    2016-10-01

    We examined how different exploratory behavioral types of largemouth bass responded to differing prey communities by determining effects on growth, survival and diet in experimental ponds. We found evidence that non-explorer largemouth bass target young-of-year bluegill early on in life, but bluegill were not an important diet item by late summer. The presence of young-of-year bluegill as prey does appear to affect the foraging strategy of the two exploring types differently. In the absence of small bluegill, both behavioral types feed primarily on benthic invertebrates and zooplankton. When small bluegill were present, we saw a shift away from zooplankton as prey for largemouth bass. However, that shift was toward more benthic invertebrates for non-exploring behavioral types and toward terrestrial insects for exploring behavioral types. Thus, it appears that prey community composition can have important effects on the way in which different behavioral types interact with their environment.

  14. Phosphorylation of ATPase subunits of the 26S proteasome.

    Science.gov (United States)

    Mason, G G; Murray, R Z; Pappin, D; Rivett, A J

    1998-07-01

    The 26S proteasome complex plays a major role in the non-lysosomal degradation of intracellular proteins. Purified 26S proteasomes give a pattern of more than 40 spots on 2D-PAGE gels. The positions of subunits have been identified by mass spectrometry of tryptic peptides and by immunoblotting with subunit-specific antipeptide antibodies. Two-dimensional polyacrylamide gel electrophoresis of proteasomes immunoprecipitated from [32P]phosphate-labelled human embryo lung L-132 cells revealed the presence of at least three major phosphorylated polypeptides among the regulatory subunits as well as the C8 and C9 components of the core 20S proteasome. Comparison with the positions of the regulatory polypeptides revealed a minor phosphorylated form to be S7 (MSS1). Antibodies against S4, S6 (TBP7) and S12 (MOV34) all cross-reacted at the position of major phosphorylated polypeptides suggesting that several of the ATPase subunits may be phosphorylated. The phosphorylation of S4 was confirmed by double immunoprecipitation experiments in which 26S proteasomes were immunoprecipitated as above and dissociated and then S4 was immunoprecipitated with subunit-specific antibodies. Antibodies against the non-ATPase subunit S10, which has been suggested by others to be phosphorylated, did not coincide with the position of a phosphorylated polypeptide. Some differences were observed in the 2D-PAGE pattern of proteasomes immunoprecipitated from cultured cells compared to purified rat liver 26S proteasomes suggesting possible differences in subunit compositions of 26S proteasomes.

  15. Anti-tumor Action and Clinical Application of Proteasome Inhibitor

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yong-ming; YU Mei-xia; LONG Hui; HUANG Shi-ang

    2008-01-01

    Ubiquitin-proteasome pathway mediates the degradation of cell protein,and cell cycle,gene translation and expression,antigen presentation and inflammatory development.Proteasome inhibitor Call inhibit growth and proliferation of tumor cell,induce apoptosis and reverse multipledrug resistance of tumor cell,increase the sensitivity of other chemomerapeutic drugs and radiotherapy,and is a novel class of potent anti-tumor agents.

  16. Rational Design of Proteasome Inhibitors as Antimalarial Drugs.

    Science.gov (United States)

    Le Chapelain, Camille; Groll, Michael

    2016-05-23

    One life, two strategies: Crucial structural differences between the human and the Plasmodium falciparum proteasomes were recently identified. A combination of cryo-EM and functional characterization enabled the design of a selective antimalarial proteasome inhibitor that shows low toxicity in the host. When used with artemisinin, this ligand offers a new approach for the efficient treatment of malaria at all stages of the parasite lifecycle.

  17. Ecological Interactions Affecting the Efficacy of Aphidius colemani in Greenhouse Crops

    Directory of Open Access Journals (Sweden)

    Sara G. Prado

    2015-06-01

    Full Text Available Aphidius colemani Viereck (Hymenoptera: Braconidae is a solitary endoparasitoid used for biological control of many economically important pest aphids. Given its widespread use, a vast array of literature on this natural enemy exists. Though often highly effective for aphid suppression, the literature reveals that A. colemani efficacy within greenhouse production systems can be reduced by many stressors, both biotic (plants, aphid hosts, other natural enemies and abiotic (climate and lighting. For example, effects from 3rd and 4th trophic levels (fungal-based control products, hyperparasitoids can suddenly decimate A. colemani populations. But, the most chronic negative effects (reduced parasitoid foraging efficiency, fitness seem to be from stressors at the first trophic level. Negative effects from the 1st trophic level are difficult to mediate since growers are usually constrained to particular plant varieties due to market demands. Major research gaps identified by our review include determining how plants, aphid hosts, and A. colemani interact to affect the net aphid population, and how production conditions such as temperature, humidity and lighting affect both the population growth rate of A. colemani and its target pest. Decades of research have made A. colemani an essential part of biological control programs in greenhouse crops. Future gains in A. colemani efficacy and aphid biological control will require an interdisciplinary, systems approach that considers plant production and climate effects at all trophic levels.

  18. Dissolved organic matter conformation and its interaction with pyrene as affected by water chemistry and concentration.

    Science.gov (United States)

    Pan, Bo; Ghosh, Saikat; Xing, Baoshan

    2008-03-01

    Water chemistry and concentration of dissolved organic matter (DOM) have been reported to affect DOM conformation and binding properties with hydrophobic organic contaminants (HOCs). However, relationship between DOM conformation and its binding properties remains unclear. We designed a multibag equilibration system (MBES) to investigate the variation of carbon-normalized sorption coefficients (K(DOC)) of pyrene at different DOM concentrations based on an identical free solute concentration at different pHs and in the presence of Al ions. In addition, we studied the conformation of DOM under different conditions via atomic force microscopy (AFM) imaging, dynamic light scattering, and zeta potential measurements. Zeta potential measurements indicated that intra- and intermolecular interaction was facilitated at low pH or with the presence of Al ions, and a more organized molecular aggregate (such as a micelle-like structure) could form, thus, enhancing K(DOC). As DOM concentration increased, DOM molecular aggregation was promoted in a way reducing K(DOC). This research is a first attempt to correlate DOM conformation with K(DOC). Aggregation of DOM molecules resulting from increased zeta potential (less negative) generally led to an increased K(DOC). Further study in this area will provide valuable information on HOC-DOM interactions, thus, leading to more accurate predictions of K(DOC).

  19. Catechol-O-methyltransferase val158met Polymorphism Interacts with Sex to Affect Face Recognition Ability

    Science.gov (United States)

    Lamb, Yvette N.; McKay, Nicole S.; Singh, Shrimal S.; Waldie, Karen E.; Kirk, Ian J.

    2016-01-01

    The catechol-O-methyltransferase (COMT) val158met polymorphism affects the breakdown of synaptic dopamine. Consequently, this polymorphism has been associated with a variety of neurophysiological and behavioral outcomes. Some of the effects have been found to be sex-specific and it appears estrogen may act to down-regulate the activity of the COMT enzyme. The dopaminergic system has been implicated in face recognition, a form of cognition for which a female advantage has typically been reported. This study aimed to investigate potential joint effects of sex and COMT genotype on face recognition. A sample of 142 university students was genotyped and assessed using the Faces I subtest of the Wechsler Memory Scale – Third Edition (WMS-III). A significant two-way interaction between sex and COMT genotype on face recognition performance was found. Of the male participants, COMT val homozygotes and heterozygotes had significantly lower scores than met homozygotes. Scores did not differ between genotypes for female participants. While male val homozygotes had significantly lower scores than female val homozygotes, no sex differences were observed in the heterozygotes and met homozygotes. This study contributes to the accumulating literature documenting sex-specific effects of the COMT polymorphism by demonstrating a COMT-sex interaction for face recognition, and is consistent with a role for dopamine in face recognition. PMID:27445927

  20. Wolbachia-Host Interactions: Host Mating Patterns Affect Wolbachia Density Dynamics.

    Directory of Open Access Journals (Sweden)

    Dong-Xiao Zhao

    Full Text Available Wolbachia are maternally inherited intracellular bacteria that infect a wide range of arthropods and cause an array of effects on host reproduction, fitness and mating behavior. Although our understanding of the Wolbachia-associated effects on hosts is rapidly expanding, our knowledge of the host factors that mediate Wolbachia dynamics is rudimentary. Here, we explore the interactions between Wolbachia and its host, the two-spotted spider mite Tetranychus urticae Koch. Our results indicate that Wolbachia induces strong cytoplasmic incompatibility (CI, increases host fecundity, but has no effects on the longevity of females and the mating competitiveness of males in T. urticae. Most importantly, host mating pattern was found to affect Wolbachia density dynamics during host aging. Mating of an uninfected mite of either sex with an infected mite attenuates the Wolbachia density in the infected mite. According to the results of Wolbachia localization, this finding may be associated with the tropism of Wolbachia for the reproductive tissue in adult spider mites. Our findings describe a new interaction between Wolbachia and their hosts.

  1. Functional brain interactions that serve cognitive-affective processing during pain and placebo analgesia.

    Science.gov (United States)

    Craggs, Jason G; Price, Donald D; Verne, G Nicholas; Perlstein, William M; Robinson, Michael M

    2007-12-01

    Pain requires the integration of sensory, cognitive, and affective information. The use of placebo is a common methodological ploy in many fields, including pain. Neuroimaging studies of pain and placebo analgesia (PA) have yet to identify a mechanism of action. Because PA must result from higher order processes, it is likely influenced by cognitive and affective dimensions of the pain experience. A network of brain regions involved in these processes includes the anterior and posterior insula (A-Ins, P-Ins), dorsal anterior cingulate cortex (DACC), dorsolateral prefrontal cortex (DLPFC), and the supplementary motor area (SMA). We used connectivity analyses to investigate the underlying mechanisms associated with Placebo analgesia in a group of chronic pain patients. Structural equation models (SEM) of fMRI data evaluated the inter-regional connectivity of these regions across three conditions: (1) initial Baseline (B1), (2) placebo (PA), and (3) Placebo Match (PM). SEM results of B1 data in the left hemisphere confirmed hypothesized regional relationships. However, inter-regional relationships were dynamic and the network models varied across hemispheres and conditions. Deviations from the B1 model in the PA and PM conditions correspond to our manipulation of expectation for pain. The dynamic changes in inter-regional influence across conditions are interpreted in the context of a self-reinforcing feedback loop involved in the induction and maintenance of PA. Although it is likely that placebo analgesia results partly from afferent inhibition of a nociceptive signal, the mechanisms likely involve the interaction of a cognitive-affective network with input from both hemispheres. PMID:17904390

  2. Factors affecting mito-nuclear codon usage interactions in the OXPHOS system of Drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Codon usage bias varies considerably among genomes and even within the genes of the same genome.In eukaryotic organisms,energy production in the form of oxidative phosphorylation(OXPHOS)is the only process under control of both nuclear and mitochondrial genomes.Although factors affecting codon usage in a single genome have been studied,this has not occurred when both interactional genomes are involved.Consequently, we investigated whether or not other factors influence codon usage of coevolved genes.We used Drosophila melanogaster as a model organism.Our χ2 test on the number of codons of nuclear and mitochondrial genes involved in the OXPHOS system was significantly different (χ2=7945.16,P<0.01).A plot of effective number of codons against GC3s content of nuclear genes showed that few genes lie on the expected curve,indicating that codon usage was random.Correspondence analysis indicated a significant correlation between axis 1 and codon adaptation index(R=0.947,P<0.01)in every nuclear gene sequence.Thus,codon usage bias of nuclear genes appeared to be affected by translational selection.Correlation between axis 1 coordinates and GC content(R=0.814.P<0.01)indicated that the codon usage of nuclear genes was also affected by GC composition.Analysis of mitochondrial genes did not reveal a significant correlation between axis 1 and any parameter.Statistical analyses indicated that codon usages of both nDNA and mtDNA were subjected to context-dependent mutations.

  3. Reconfiguration of the proteasome during chaperone-mediated assembly

    Science.gov (United States)

    Park, Soyeon; Li, Xueming; Kim, Ho Min; Singh, Chingakham Ranjit; Tian, Geng; Hoyt, Martin A.; Lovell, Scott; Battaile, Kevin P.; Zolkiewski, Michal; Coffino, Philip; Roelofs, Jeroen; Cheng, Yifan; Finley, Daniel

    2013-01-01

    The proteasomal ATPase ring, comprising Rpt1-Rpt6, associates with the heptameric α ring of the proteasome core particle (CP) in the mature proteasome, with the Rpt C-terminal tails inserting into pockets of the α ring1–4. Rpt ring assembly is mediated by four chaperones, each binding a distinct Rpt subunit5–10. We report that the base subassembly of the proteasome, which includes the Rpt ring, forms a high affinity complex with the CP. This complex is subject to active dissociation by the chaperones Hsm3, Nas6, and Rpn14. Chaperone-mediated dissociation was abrogated by a nonhydrolyzable ATP analog, indicating that chaperone action is coupled to nucleotide hydrolysis by the Rpt ring. Unexpectedly, synthetic Rpt tail peptides bound α pockets with poor specificity, except for Rpt6, which uniquely bound the α2/α3 pocket. Although the Rpt6 tail is not visualized within an α pocket in mature proteasomes2–4, it inserts into the α2/α3 pocket in the base-CP complex and is important for complex formation. Thus, the Rpt-CP interface is reconfigured when the lid complex joins the nascent proteasome to form the mature holoenzyme. PMID:23644457

  4. Studies on terrein as a new class of proteasome inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Demasi, M.; Felicio, A.L.; Lima, C. [Instituto Butantan, Sao Paulo, SP (Brazil); Pacheco, A.O.; Leite, H.G.; Andrade, L.H. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica], e-mail: marimasi@butantan.gov.br

    2010-07-01

    The proteasome is an intracellular multicatalytic protease involved in the cell cycle regulation, signaling response, antigen presentation and apoptosis. Since proteasome inhibitors promote cell death by apoptosis, they have been proposed as new anti-tumoral drugs. Terrein, a secondary metabolite secreted by the fungus Aspergillus terreus, was firstly described in 1935. In the present work we report that terrein isolated through the screening for inhibitors of the 20S proteasome showed inhibitory effect upon both chymotrypsin- and trypsin-like activities of the multicatalytic core particle, the 20S proteasome. Despite of the high inhibitory concentration determined in vitro, that verified by incubating cells (fibroblasts and a pulmonary tumor cell line) in the presence of terrein was 4-fold lower indicating the proteasome as a selective intracellular target. Moreover, terrein promoted apoptotic cell death on both fibroblasts and pulmonary tumor cell line tested. Although terrein concentrations (mM range) necessary to elicit apoptosis in the cellular models herein tried were high when compared to those (muM and nM range) of other inhibitors recently described, its chemical structure is not correlated to any other inhibitor reported thus far. Therefore, the present results point out for the possibility of exploring terrein as a new molecular fragment for the development of synthetic proteasome inhibitors. (author)

  5. Proteasome dysfunction induces muscle growth defects and protein aggregation.

    Science.gov (United States)

    Kitajima, Yasuo; Tashiro, Yoshitaka; Suzuki, Naoki; Warita, Hitoshi; Kato, Masaaki; Tateyama, Maki; Ando, Risa; Izumi, Rumiko; Yamazaki, Maya; Abe, Manabu; Sakimura, Kenji; Ito, Hidefumi; Urushitani, Makoto; Nagatomi, Ryoichi; Takahashi, Ryosuke; Aoki, Masashi

    2014-12-15

    The ubiquitin-proteasome and autophagy-lysosome pathways are the two major routes of protein and organelle clearance. The role of the proteasome pathway in mammalian muscle has not been examined in vivo. In this study, we report that the muscle-specific deletion of a crucial proteasomal gene, Rpt3 (also known as Psmc4), resulted in profound muscle growth defects and a decrease in force production in mice. Specifically, developing muscles in conditional Rpt3-knockout animals showed dysregulated proteasomal activity. The autophagy pathway was upregulated, but the process of autophagosome formation was impaired. A microscopic analysis revealed the accumulation of basophilic inclusions and disorganization of the sarcomeres in young adult mice. Our results suggest that appropriate proteasomal activity is important for muscle growth and for maintaining myofiber integrity in collaboration with autophagy pathways. The deletion of a component of the proteasome complex contributed to myofiber degeneration and weakness in muscle disorders that are characterized by the accumulation of abnormal inclusions.

  6. The interaction of affective states and cognitive vulnerabilities in the prediction of non-suicidal self-injury.

    Science.gov (United States)

    Cohen, Jonah N; Stange, Jonathan P; Hamilton, Jessica L; Burke, Taylor A; Jenkins, Abigail; Ong, Mian-Li; Heimberg, Richard G; Abramson, Lyn Y; Alloy, Lauren B

    2015-01-01

    Non-suicidal self-injury (NSSI) is a serious public health concern and remains poorly understood. This study sought to identify both cognitive and affective vulnerabilities to NSSI and examine their interaction in the prediction of NSSI. A series of regressions indicated that low levels of positive affect (PA) moderated the relationships between self-criticism and brooding and NSSI. The associations of self-criticism and brooding with greater frequency of NSSI were attenuated by higher levels of PA. The interaction of cognitive and affective vulnerabilities is discussed within the context of current NSSI theory.

  7. Proteasome inhibition mediates p53 reactivation and anti-cancer activity of 6-gingerol in cervical cancer cells.

    Science.gov (United States)

    Rastogi, Namrata; Duggal, Shivali; Singh, Shailendra Kumar; Porwal, Konica; Srivastava, Vikas Kumar; Maurya, Rakesh; Bhatt, M L B; Mishra, Durga Prasad

    2015-12-22

    Human papilloma virus (HPV) expressing E6 and E7 oncoproteins, is known to inactivate the tumor suppressor p53 through proteasomal degradation in cervical cancers. Therefore, use of small molecules for inhibition of proteasome function and induction of p53 reactivation is a promising strategy for induction of apoptosis in cervical cancer cells. The polyphenolic alkanone, 6-Gingerol (6G), present in the pungent extracts of ginger (Zingiber officinale Roscoe) has shown potent anti-tumorigenic and pro-apoptotic activities against a variety of cancers. In this study we explored the molecular mechanism of action of 6G in human cervical cancer cells in vitro and in vivo. 6G potently inhibited proliferation of the HPV positive cervical cancer cells. 6G was found to: (i) inhibit the chymotrypsin activity of proteasomes, (ii) induce reactivation of p53, (iii) increase levels of p21, (iv) induce DNA damage and G2/M cell cycle arrest, (v) alter expression levels of p53-associated apoptotic markers like, cleaved caspase-3 and PARP, and (vi) potentiate the cytotoxicity of cisplatin. 6G treatment induced significant reduction of tumor volume, tumor weight, proteasome inhibition and p53 accumulation in HeLa xenograft tumor cells in vivo. The 6G treatment was devoid of toxic effects as it did not affect body weights, hematological and osteogenic parameters. Taken together, our data underscores the therapeutic and chemosensitizing effects of 6G in the management and treatment of cervical cancer. PMID:26621832

  8. Selective increase of in vivo firing frequencies in DA SN neurons after proteasome inhibition in the ventral midbrain.

    Science.gov (United States)

    Subramaniam, Mahalakshmi; Kern, Beatrice; Vogel, Simone; Klose, Verena; Schneider, Gaby; Roeper, Jochen

    2014-09-01

    The impairment of protein degradation via the ubiquitin-proteasome system (UPS) is present in sporadic Parkinson's disease (PD), and might play a key role in selective degeneration of vulnerable dopamine (DA) neurons in the substantia nigra pars compacta (SN). Further evidence for a causal role of dysfunctional UPS in familial PD comes from mutations in parkin, which results in a loss of function of an E3-ubiquitin-ligase. In a mouse model, genetic inactivation of an essential component of the 26S proteasome lead to widespread neuronal degeneration including DA midbrain neurons and the formation of alpha-synuclein-positive inclusion bodies, another hallmark of PD. Studies using pharmacological UPS inhibition in vivo had more mixed results, varying from extensive degeneration to no loss of DA SN neurons. However, it is currently unknown whether UPS impairment will affect the neurophysiological functions of DA midbrain neurons. To answer this question, we infused a selective proteasome inhibitor into the ventral midbrain in vivo and recorded single DA midbrain neurons 2 weeks after the proteasome challenge. We found a selective increase in the mean in vivo firing frequencies of identified DA SN neurons in anesthetized mice, while those in the ventral tegmental area (VTA) were unaffected. Our results demonstrate that a single-hit UPS inhibition is sufficient to induce a stable and selective hyperexcitability phenotype in surviving DA SN neurons in vivo. This might imply that UPS dysfunction sensitizes DA SN neurons by enhancing 'stressful pacemaking'.

  9. Great Expectations? Self-Expansion Motivation, Social Self-Efficacy, and Interaction Expectations Affect Interest in Cross-Group Interactions

    OpenAIRE

    Lorenzo, Genevieve Louise

    2014-01-01

    While high motivation to expand the self may lead to interest in cross-ethnic interactions, social self-efficacy may moderate this effect, such that those high in social self-efficacy will show a stronger effect of self-expansion motivation on interest in cross-group interactions. Study 1 failed to show the predicted interaction, but did show that social self-efficacy played a significant role in predicting interest in cross-group interactions. Study 2 extended Study 1, manipulating participa...

  10. Roostocks/Scion/Nitrogen Interactions Affect Secondary Metabolism in the Grape Berry

    Science.gov (United States)

    Habran, Aude; Commisso, Mauro; Helwi, Pierre; Hilbert, Ghislaine; Negri, Stefano; Ollat, Nathalie; Gomès, Eric; van Leeuwen, Cornelis; Guzzo, Flavia; Delrot, Serge

    2016-01-01

    The present work investigates the interactions between soil content, rootstock, and scion by focusing on the effects of roostocks and nitrogen supply on grape berry content. Scions of Cabernet Sauvignon (CS) and Pinot Noir (PN) varieties were grafted either on Riparia Gloire de Montpellier (RGM) or 110 Richter (110R) rootstock. The 4 rooststock/scion combinations were fertilized with 3 different levels of nitrogen after fruit set. Both in 2013 and 2014, N supply increased N uptake by the plants, and N content both in vegetative and reproductory organs. Rootstock, variety and year affected berry weight at harvest, while nitrogen did not affect significantly this parameter. Grafting on RGM consistently increased berry weight compared to 110R. PN consistently produced bigger berries than CS. CS berries were heavier in 2014 than in 2013, but the year effect was less marked for PN berries. The berries were collected between veraison and maturity, separated in skin and pulp, and their content was analyzed by conventional analytical procedures and untargeted metabolomics. For anthocyanins, the relative quantitation was fairly comparable with both LC-MS determination and HPLC-DAD, which is a fully quantitative technique. The data show complex responses of the metabolite content (sugars, organic acids, amino acids, anthocyanins, flavonols, flavan-3-ols/procyanidins, stilbenes, hydroxycinnamic, and hydroxybenzoic acids) that depend on the rootstock, the scion, the vintage, the nitrogen level, the berry compartment. This opens a wide range of possibilities to adjust the content of these compounds through the choice of the roostock, variety and nitrogen fertilization. PMID:27555847

  11. Roostocks/Scion/Nitrogen Interactions Affect Secondary Metabolism in the Grape Berry.

    Science.gov (United States)

    Habran, Aude; Commisso, Mauro; Helwi, Pierre; Hilbert, Ghislaine; Negri, Stefano; Ollat, Nathalie; Gomès, Eric; van Leeuwen, Cornelis; Guzzo, Flavia; Delrot, Serge

    2016-01-01

    The present work investigates the interactions between soil content, rootstock, and scion by focusing on the effects of roostocks and nitrogen supply on grape berry content. Scions of Cabernet Sauvignon (CS) and Pinot Noir (PN) varieties were grafted either on Riparia Gloire de Montpellier (RGM) or 110 Richter (110R) rootstock. The 4 rooststock/scion combinations were fertilized with 3 different levels of nitrogen after fruit set. Both in 2013 and 2014, N supply increased N uptake by the plants, and N content both in vegetative and reproductory organs. Rootstock, variety and year affected berry weight at harvest, while nitrogen did not affect significantly this parameter. Grafting on RGM consistently increased berry weight compared to 110R. PN consistently produced bigger berries than CS. CS berries were heavier in 2014 than in 2013, but the year effect was less marked for PN berries. The berries were collected between veraison and maturity, separated in skin and pulp, and their content was analyzed by conventional analytical procedures and untargeted metabolomics. For anthocyanins, the relative quantitation was fairly comparable with both LC-MS determination and HPLC-DAD, which is a fully quantitative technique. The data show complex responses of the metabolite content (sugars, organic acids, amino acids, anthocyanins, flavonols, flavan-3-ols/procyanidins, stilbenes, hydroxycinnamic, and hydroxybenzoic acids) that depend on the rootstock, the scion, the vintage, the nitrogen level, the berry compartment. This opens a wide range of possibilities to adjust the content of these compounds through the choice of the roostock, variety and nitrogen fertilization. PMID:27555847

  12. Earthworm-Mycorrhiza Interactions Can Affect the Diversity, Structure and Functioning of Establishing Model Grassland Communities

    Science.gov (United States)

    Zaller, Johann G.; Heigl, Florian; Grabmaier, Andrea; Lichtenegger, Claudia; Piller, Katja; Allabashi, Roza; Frank, Thomas; Drapela, Thomas

    2011-01-01

    Both earthworms and arbuscular mycorrhizal fungi (AMF) are important ecosystem engineers co-occurring in temperate grasslands. However, their combined impacts during grassland establishment are poorly understood and have never been studied. We used large mesocosms to study the effects of different functional groups of earthworms (i.e., vertically burrowing anecics vs. horizontally burrowing endogeics) and a mix of four AMF taxa on the establishment, diversity and productivity of plant communities after a simulated seed rain of 18 grassland species comprising grasses, non-leguminous forbs and legumes. Moreover, effects of earthworms and/or AMF on water infiltration and leaching of ammonium, nitrate and phosphate were determined after a simulated extreme rainfall event (40 l m−2). AMF colonisation of all three plant functional groups was altered by earthworms. Seedling emergence and diversity was reduced by anecic earthworms, however only when AMF were present. Plant density was decreased in AMF-free mesocosms when both anecic and endogeic earthworms were active; with AMF also anecics reduced plant density. Plant shoot and root biomass was only affected by earthworms in AMF-free mesocosms: shoot biomass increased due to the activity of either anecics or endogeics; root biomass increased only when anecics were active. Water infiltration increased when earthworms were present in the mesocosms but remained unaffected by AMF. Ammonium leaching was increased only when anecics or a mixed earthworm community was active but was unaffected by AMF; nitrate and phosphate leaching was neither affected by earthworms nor AMF. Ammonium leaching decreased with increasing plant density, nitrate leaching decreased with increasing plant diversity and density. In order to understand the underlying processes of these interactions further investigations possibly under field conditions using more diverse belowground communities are required. Nevertheless, this study demonstrates that

  13. Earthworm-mycorrhiza interactions can affect the diversity, structure and functioning of establishing model grassland communities.

    Directory of Open Access Journals (Sweden)

    Johann G Zaller

    Full Text Available Both earthworms and arbuscular mycorrhizal fungi (AMF are important ecosystem engineers co-occurring in temperate grasslands. However, their combined impacts during grassland establishment are poorly understood and have never been studied. We used large mesocosms to study the effects of different functional groups of earthworms (i.e., vertically burrowing anecics vs. horizontally burrowing endogeics and a mix of four AMF taxa on the establishment, diversity and productivity of plant communities after a simulated seed rain of 18 grassland species comprising grasses, non-leguminous forbs and legumes. Moreover, effects of earthworms and/or AMF on water infiltration and leaching of ammonium, nitrate and phosphate were determined after a simulated extreme rainfall event (40 l m(-2. AMF colonisation of all three plant functional groups was altered by earthworms. Seedling emergence and diversity was reduced by anecic earthworms, however only when AMF were present. Plant density was decreased in AMF-free mesocosms when both anecic and endogeic earthworms were active; with AMF also anecics reduced plant density. Plant shoot and root biomass was only affected by earthworms in AMF-free mesocosms: shoot biomass increased due to the activity of either anecics or endogeics; root biomass increased only when anecics were active. Water infiltration increased when earthworms were present in the mesocosms but remained unaffected by AMF. Ammonium leaching was increased only when anecics or a mixed earthworm community was active but was unaffected by AMF; nitrate and phosphate leaching was neither affected by earthworms nor AMF. Ammonium leaching decreased with increasing plant density, nitrate leaching decreased with increasing plant diversity and density. In order to understand the underlying processes of these interactions further investigations possibly under field conditions using more diverse belowground communities are required. Nevertheless, this study

  14. Roostocks/scion/ nitrogen interactions affect secondary metabolism in the grape berry

    Directory of Open Access Journals (Sweden)

    Aude Habran

    2016-08-01

    Full Text Available ABSTRACT : The present work investigates the interactions between soil content, rootstock and scion by focusing on the effects of roostocks and nitrogen supply on grape berry content. Scions of Cabernet Sauvignon (CS and Pinot Noir (PN varieties were grafted either on Riparia Gloire de Montpellier (RGM or 110 Richter (110R rootstock. The 4 rooststock/scion combinations were fertilized with 3 different levels of nitrogen after fruit set. Both in 2013 and 2014, N supply increased N uptake by the plants, and N content both in vegetative and reproductory organs. Rootstock, variety and year affected berry weight at harvest, while nitrogen did not affect significantly this parameter. Grafting on RGM consistently increased berry weight compared to 110R. PN consistently produced bigger berries than CS. CS berries were heavier in 2014 than in 2013, but the year effect was less marked for PN berries. The berries were collected between veraison and maturity, separated in skin and pulp, and their content was analyzed by conventional analytical procedures and untargeted metabolomics. For anthocyanins, the relative quantitation was fairly comparable with both LC-MS determination and HPLC-DAD, which is a fully quantitative technique. The data show complex responses of the metabolite content (sugars, organic acids, amino acids, anthocyanins, flavonols, flavan-3-ols/procyanidins, stilbenes, hydroxycinnamic and hydroxybenzoic acids. that depend on the rootstock, the scion, the vintage, the nitrogen level, the berry compartment. This opens a wide range of possibilities to adjust the content of these compounds through the choice of the roostock, variety and nitrogen fertilization.

  15. Stress and affective disorders: animal models elucidating the molecular basis of neuroendocrine-behavior interactions.

    Science.gov (United States)

    Touma, C

    2011-05-01

    Profound dysfunctions in several neuroendocrine systems have been described in patients suffering from affective disorders such as major depression. In order to elucidate the mechanisms underlying these functional alterations, animal models including mice genetically modified by either direct gene-targeting or by selective breeding approaches have been used exceedingly, revealing valuable insights into neuroendocrine pathways conserved between rodents and men. This review focuses on altered function and regulation of the hypothalamic-pituitary-adrenocortical axis, including its involvement in emotionality and stress responsiveness. In this context, the corticotropin-releasing hormone system and disturbances in glucocorticoid receptor signaling seem to be of central importance. However, changes in the expression and release patterns of vasopressin, dopamine and serotonin have also been shown to contribute to variation in emotionality, stress coping, cognitive functions and social behaviors. Affective disorders show a high degree of complexity, involving a multitude of molecular, neuroendocrine, and behavioral alterations as well as an intense gene-environment interaction, making it difficult to dissociate the primary causes from secondary consequences of the disease. Thus, interdisciplinary research, as applied in the emerging field of systems biology, involving adequate animal models and combined methodologies can significantly contribute to our understanding regarding the transmission of genetic predispositions into clinically relevant endophenotypes. It is only with deep insight into the mechanisms by which the stress hormone systems are regulated that novel treatment strategies and promising targets for therapeutic interventions can be developed in the future. Such in-depth understanding is ultimately essential to realizing our goal of predictive, preventive, and personalized medicine. PMID:21544741

  16. Keeper-Animal Interactions: Differences between the Behaviour of Zoo Animals Affect Stockmanship.

    Science.gov (United States)

    Ward, Samantha J; Melfi, Vicky

    2015-01-01

    Stockmanship is a term used to describe the management of animals with a good stockperson someone who does this in a in a safe, effective, and low-stress manner for both the stock-keeper and animals involved. Although impacts of unfamiliar zoo visitors on animal behaviour have been extensively studied, the impact of stockmanship i.e familiar zoo keepers is a new area of research; which could reveal significant ramifications for zoo animal behaviour and welfare. It is likely that different relationships are formed dependant on the unique keeper-animal dyad (human-animal interaction, HAI). The aims of this study were to (1) investigate if unique keeper-animal dyads were formed in zoos, (2) determine whether keepers differed in their interactions towards animals regarding their attitude, animal knowledge and experience and (3) explore what factors affect keeper-animal dyads and ultimately influence animal behaviour and welfare. Eight black rhinoceros (Diceros bicornis), eleven Chapman's zebra (Equus burchellii), and twelve Sulawesi crested black macaques (Macaca nigra) were studied in 6 zoos across the UK and USA. Subtle cues and commands directed by keepers towards animals were identified. The animals latency to respond and the respective behavioural response (cue-response) was recorded per keeper-animal dyad (n = 93). A questionnaire was constructed following a five-point Likert Scale design to record keeper demographic information and assess the job satisfaction of keepers, their attitude towards the animals and their perceived relationship with them. There was a significant difference in the animals' latency to appropriately respond after cues and commands from different keepers, indicating unique keeper-animal dyads were formed. Stockmanship style was also different between keepers; two main components contributed equally towards this: "attitude towards the animals" and "knowledge and experience of the animals". In this novel study, data demonstrated unique dyads

  17. Keeper-Animal Interactions: Differences between the Behaviour of Zoo Animals Affect Stockmanship.

    Directory of Open Access Journals (Sweden)

    Samantha J Ward

    Full Text Available Stockmanship is a term used to describe the management of animals with a good stockperson someone who does this in a in a safe, effective, and low-stress manner for both the stock-keeper and animals involved. Although impacts of unfamiliar zoo visitors on animal behaviour have been extensively studied, the impact of stockmanship i.e familiar zoo keepers is a new area of research; which could reveal significant ramifications for zoo animal behaviour and welfare. It is likely that different relationships are formed dependant on the unique keeper-animal dyad (human-animal interaction, HAI. The aims of this study were to (1 investigate if unique keeper-animal dyads were formed in zoos, (2 determine whether keepers differed in their interactions towards animals regarding their attitude, animal knowledge and experience and (3 explore what factors affect keeper-animal dyads and ultimately influence animal behaviour and welfare. Eight black rhinoceros (Diceros bicornis, eleven Chapman's zebra (Equus burchellii, and twelve Sulawesi crested black macaques (Macaca nigra were studied in 6 zoos across the UK and USA. Subtle cues and commands directed by keepers towards animals were identified. The animals latency to respond and the respective behavioural response (cue-response was recorded per keeper-animal dyad (n = 93. A questionnaire was constructed following a five-point Likert Scale design to record keeper demographic information and assess the job satisfaction of keepers, their attitude towards the animals and their perceived relationship with them. There was a significant difference in the animals' latency to appropriately respond after cues and commands from different keepers, indicating unique keeper-animal dyads were formed. Stockmanship style was also different between keepers; two main components contributed equally towards this: "attitude towards the animals" and "knowledge and experience of the animals". In this novel study, data demonstrated

  18. The intracellular domain of Dumbfounded affects myoblast fusion efficiency and interacts with Rolling pebbles and Loner.

    Directory of Open Access Journals (Sweden)

    Sarada Bulchand

    Full Text Available Drosophila body wall muscles are multinucleated syncytia formed by successive fusions between a founder myoblast and several fusion competent myoblasts. Initial fusion gives rise to a bi/trinucleate precursor followed by more fusion cycles forming a mature muscle. This process requires the functions of various molecules including the transmembrane myoblast attractants Dumbfounded (Duf and its paralogue Roughest (Rst, a scaffold protein Rolling pebbles (Rols and a guanine nucleotide exchange factor Loner. Fusion completely fails in a duf, rst mutant, and is blocked at the bi/trinucleate stage in rols and loner single mutants. We analysed the transmembrane and intracellular domains of Duf, by mutating conserved putative signaling sites and serially deleting the intracellular domain. These were tested for their ability to translocate and interact with Rols and Loner and to rescue the fusion defect in duf, rst mutant embryos. Studying combinations of double mutants, further tested the function of Rols, Loner and other fusion molecules. Here we show that serial truncations of the Duf intracellular domain successively compromise its function to translocate and interact with Rols and Loner in addition to affecting myoblast fusion efficiency in embryos. Putative phosphorylation sites function additively while the extreme C terminus including a PDZ binding domain is dispensable for its function. We also show that fusion is completely blocked in a rols, loner double mutant and is compromised in other double mutants. These results suggest an additive function of the intracellular domain of Duf and an early function of Rols and Loner which is independent of Duf.

  19. Macrofauna assemblage composition and soil moisture interact to affect soil ecosystem functions

    Science.gov (United States)

    Collison, E. J.; Riutta, T.; Slade, E. M.

    2013-02-01

    Changing climatic conditions and habitat fragmentation are predicted to alter the soil moisture conditions of temperate forests. It is not well understood how the soil macrofauna community will respond to changes in soil moisture, and how changes to species diversity and community composition may affect ecosystem functions, such as litter decomposition and soil fluxes. Moreover, few studies have considered the interactions between the abiotic and biotic factors that regulate soil processes. Here we attempt to disentangle the interactive effects of two of the main factors that regulate soil processes at small scales - moisture and macrofauna assemblage composition. The response of assemblages of three common temperate soil invertebrates (Glomeris marginata Villers, Porcellio scaber Latreille and Philoscia muscorum Scopoli) to two contrasting soil moisture levels was examined in a series of laboratory mesocosm experiments. The contribution of the invertebrates to the leaf litter mass loss of two common temperate tree species of contrasting litter quality (easily decomposing Fraxinus excelsior L. and recalcitrant Quercus robur L.) and to soil CO2 fluxes were measured. Both moisture conditions and litter type influenced the functioning of the invertebrate assemblages, which was greater in high moisture conditions compared with low moisture conditions and on good quality vs. recalcitrant litter. In high moisture conditions, all macrofauna assemblages functioned at equal rates, whereas in low moisture conditions there were pronounced differences in litter mass loss among the assemblages. This indicates that species identity and assemblage composition are more important when moisture is limited. We suggest that complementarity between macrofauna species may mitigate the reduced functioning of some species, highlighting the importance of maintaining macrofauna species richness.

  20. The Identification of Novel Protein-Protein Interactions in Liver that Affect Glucagon Receptor Activity.

    Directory of Open Access Journals (Sweden)

    Junfeng Han

    Full Text Available Glucagon regulates glucose homeostasis by controlling glycogenolysis and gluconeogenesis in the liver. Exaggerated and dysregulated glucagon secretion can exacerbate hyperglycemia contributing to type 2 diabetes (T2D. Thus, it is important to understand how glucagon receptor (GCGR activity and signaling is controlled in hepatocytes. To better understand this, we sought to identify proteins that interact with the GCGR to affect ligand-dependent receptor activation. A Flag-tagged human GCGR was recombinantly expressed in Chinese hamster ovary (CHO cells, and GCGR complexes were isolated by affinity purification (AP. Complexes were then analyzed by mass spectrometry (MS, and protein-GCGR interactions were validated by co-immunoprecipitation (Co-IP and Western blot. This was followed by studies in primary hepatocytes to assess the effects of each interactor on glucagon-dependent glucose production and intracellular cAMP accumulation, and then in immortalized CHO and liver cell lines to further examine cell signaling. Thirty-three unique interactors were identified from the AP-MS screening of GCGR expressing CHO cells in both glucagon liganded and unliganded states. These studies revealed a particularly robust interaction between GCGR and 5 proteins, further validated by Co-IP, Western blot and qPCR. Overexpression of selected interactors in mouse hepatocytes indicated that two interactors, LDLR and TMED2, significantly enhanced glucagon-stimulated glucose production, while YWHAB inhibited glucose production. This was mirrored with glucagon-stimulated cAMP production, with LDLR and TMED2 enhancing and YWHAB inhibiting cAMP accumulation. To further link these interactors to glucose production, key gluconeogenic genes were assessed. Both LDLR and TMED2 stimulated while YWHAB inhibited PEPCK and G6Pase gene expression. In the present study, we have probed the GCGR interactome and found three novel GCGR interactors that control glucagon

  1. The dynamic reactance interaction – How vested interests affect people’s experience, behavior, and cognition in social interactions

    Directory of Open Access Journals (Sweden)

    Christina eSteindl

    2015-11-01

    Full Text Available In social interactions, individuals may sometimes pursue their own interests at the expense of their interaction partner. Such self-interested behaviors impose a threat to the interaction partner’s freedom to act. The current article investigates this threat in the context of interdependence and reactance theory. We explore how vested interests influence reactance process stages of an advisor-client interaction. We aim to explore the interactional process that evolves. In two studies, participants took the perspective of a doctor (advisor or a patient (client. In both studies we incorporated a vested interest. In Study 1 (N=82 we found that in response to a vested interest of their interaction partner, patients indicated a stronger experience of reactance, more aggressive behavioral intentions, and more biased cognitions than doctors. A serial multiple mediation revealed that a vested interest engendered mistrust toward the interaction partner and this mistrust led to an emerging reactance process. Study 2 (N=207 further demonstrated that doctors expressed their reactance in a subtle way: They revealed a classic confirmation bias when searching for additional information on their preliminary decision preference, indicating stronger defense motivation. We discuss how these findings can help us to understand how social interactions develop dynamically.

  2. The Age of Cortical Neural Networks Affects Their Interactions with Magnetic Nanoparticles.

    Science.gov (United States)

    Tay, Andy; Kunze, Anja; Jun, Dukwoo; Hoek, Eric; Di Carlo, Dino

    2016-07-01

    Despite increasing use of nanotechnology in neuroscience, the characterization of interactions between magnetic nanoparticles (MNPs) and primary cortical neural networks remains underdeveloped. In particular, how the age of primary neural networks affects MNP uptake and endocytosis is critical when considering MNP-based therapies for age-related diseases. Here, primary cortical neural networks are cultured up to 4 weeks and with CCL11/eotaxin, an age-inducing chemokine, to create aged neural networks. As the neural networks are aged, their association with membrane-bound starch-coated ferromagnetic nanoparticles (fMNPs) increases while their endocytic mechanisms are impaired, resulting in reduced internalization of chitosan-coated fMNPs. The age of the neurons also negates the neuroprotective effects of chitosan coatings on fMNPs, attributing to decreased intracellular trafficking and increased colocalization of MNPs with lysosomes. These findings demonstrate the importance of age and developmental stage of primary neural cells when developing in vitro models for fMNP therapeutics targeting age-related diseases. PMID:27228954

  3. Disruption of adult neurogenesis in the olfactory bulb affects social interaction but not maternal behavior

    Directory of Open Access Journals (Sweden)

    Claudia E Feierstein

    2010-12-01

    Full Text Available Adult-born neurons arrive to the olfactory bulb and integrate into the existing circuit throughout life. Despite the prevalence of this phenomenon, its functional impact is still poorly understood. Recent studies point to the importance of newly generated neurons to olfactory learning and memory. Adult neurogenesis is regulated by a variety of factors, notably by instances related to reproductive behavior, such as exposure to mating partners, pregnancy and lactation, and exposure to offspring. To study the contribution of olfactory neurogenesis to maternal behavior and social recognition, here we selectively disrupted olfactory bulb neurogenesis using focal irradiation of the subventricular zone in adult female mice. We show that reduction of olfactory neurogenesis results in an abnormal social interaction pattern with male, but not female, conspecifics; we suggest that this effect could result from inability to detect or discriminate male odors and could therefore have implications for the recognition of potential mating partners. Disruption of olfactory bulb neurogenesis, however, neither impaired maternal-related behaviors, nor did it affect the ability of mothers to discriminate their own progeny from others.

  4. Zn—Cu Interaction Affecting Zn Adsorption and Plant Availability in a Metal—Contaminated Soil

    Institute of Scientific and Technical Information of China (English)

    D.L.Rimmer; LuoYongming

    1996-01-01

    In a previous greenhouse experiment,we showed that there was an interaction between cu and Zn,which affected growth and metal uptake by young barley plants grown on soil to which Cd,Cu,Pb,and Zn had been added.We suggested that the underlying mechanism was the control of the amount of plant-available Zn by competitive adsorption between Cu and Zn,In order to test this hypothesis,the adsorption of Zn alone,and in the presence of added Cd,Cu and Pb,has been measured using the same soil.Following adsorption,the extractability of the Zn in CaCl2 solution was measured .The adsorption isotherms showed that of the added metals only Cu had a large effect on Zn adsorption.The effect of Cu was to reduce Zn adsoption and to increase the amount of CaCl2-extractable(i.e.plant-available) Zn,in agreement with the conclusions from the greenhouse experiment.The magnitude of the effect of Cu on plant-avalilable Zn was similar in both experiments.

  5. Interactions of warming and exposure affect susceptibility to parasite infection in a temperate fish species.

    Science.gov (United States)

    Sheath, Danny J; Andreou, Demetra; Britton, J Robert

    2016-09-01

    Predicting how elevated temperatures from climate change alter host-parasite interactions requires understandings of how warming affects host susceptibility and parasite virulence. Here, the effect of elevated water temperature and parasite exposure level was tested on parasite prevalence, abundance and burden, and on fish growth, using Pomphorhynchus laevis and its fish host Squalius cephalus. At 60 days post-exposure, prevalence was higher at the elevated temperature (22 °C) than ambient temperature (18 °C), with infections achieved at considerably lower levels of exposure. Whilst parasite number was significantly higher in infected fish at 22 °C, both mean parasite weight and parasite burden was significantly higher at 18 °C. There were, however, no significant relationships between fish growth rate and temperature, parasite exposure, and the infection parameters. Thus, whilst elevated temperature significantly influenced parasite infection rates, it also impacted parasite development rates, suggesting warming could have complex implications for parasite dynamics and host resistance. PMID:27225942

  6. The Age of Cortical Neural Networks Affects Their Interactions with Magnetic Nanoparticles.

    Science.gov (United States)

    Tay, Andy; Kunze, Anja; Jun, Dukwoo; Hoek, Eric; Di Carlo, Dino

    2016-07-01

    Despite increasing use of nanotechnology in neuroscience, the characterization of interactions between magnetic nanoparticles (MNPs) and primary cortical neural networks remains underdeveloped. In particular, how the age of primary neural networks affects MNP uptake and endocytosis is critical when considering MNP-based therapies for age-related diseases. Here, primary cortical neural networks are cultured up to 4 weeks and with CCL11/eotaxin, an age-inducing chemokine, to create aged neural networks. As the neural networks are aged, their association with membrane-bound starch-coated ferromagnetic nanoparticles (fMNPs) increases while their endocytic mechanisms are impaired, resulting in reduced internalization of chitosan-coated fMNPs. The age of the neurons also negates the neuroprotective effects of chitosan coatings on fMNPs, attributing to decreased intracellular trafficking and increased colocalization of MNPs with lysosomes. These findings demonstrate the importance of age and developmental stage of primary neural cells when developing in vitro models for fMNP therapeutics targeting age-related diseases.

  7. The murine cardiac 26S proteasome: an organelle awaiting exploration.

    Science.gov (United States)

    Gomes, Aldrin V; Zong, Chenggong; Edmondson, Ricky D; Berhane, Beniam T; Wang, Guang-Wu; Le, Steven; Young, Glen; Zhang, Jun; Vondriska, Thomas M; Whitelegge, Julian P; Jones, Richard C; Joshua, Irving G; Thyparambil, Sheeno; Pantaleon, Dawn; Qiao, Joe; Loo, Joseph; Ping, Peipei

    2005-06-01

    Multiprotein complexes have been increasingly recognized as essential functional units for a variety of cellular processes, including the protein degradation system. Selective degradation of proteins in eukaryotes is primarily conducted by the ubiquitin proteasome system. The current knowledge base, pertaining to the proteasome complexes in mammalian cells, relies largely upon information gained in the yeast system, where the 26S proteasome is hypothesized to contain a 20S multiprotein core complex and one or two 19S regulatory complexes. To date, the molecular structure of the proteasome system, the proteomic composition of the entire 26S multiprotein complexes, and the specific designated function of individual components within this essential protein degradation system in the heart remain virtually unknown. A functional proteomic approach, employing multidimensional chromatography purification combined with liquid chromatography tandem mass spectrometry and protein chemistry, was utilized to explore the murine cardiac 26S proteasome system. This article presents an overview on the subject of protein degradation in mammalian cells. In addition, this review shares the limited information that has been garnered thus far pertaining to the molecular composition, function, and regulation of this important organelle in the cardiac cells. PMID:16093497

  8. Yeast Interacting Proteins Database: YIL007C, YOR117W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available YIL007C NAS2 Proteasome-interacting protein involved in the assembly of the base su... - - - - - 0 0 3 4 Show YIL007C Bait ORF YIL007C Bait gene name NAS2 Bait description Proteasome-interacti

  9. Affiliation and control in marital interaction: interpersonal complementarity is present but is not associated with affect or relationship quality.

    Science.gov (United States)

    Cundiff, Jenny M; Smith, Timothy W; Butner, Jonathan; Critchfield, Kenneth L; Nealey-Moore, Jill

    2015-01-01

    The principle of complementarity in interpersonal theory states that an actor's behavior tends to "pull, elicit, invite, or evoke" responses from interaction partners who are similar in affiliation (i.e., warmth vs. hostility) and opposite in control (i.e., dominance vs. submissiveness). Furthermore, complementary interactions are proposed to evoke less negative affect and promote greater relationship satisfaction. These predictions were examined in two studies of married couples. Results suggest that complementarity in affiliation describes a robust general pattern of marital interaction, but complementarity in control varies across contexts. Consistent with behavioral models of marital interaction, greater levels of affiliation and lower control by partners-not complementarity in affiliation or control-were associated with less anger and anxiety and greater relationship quality. Partners' levels of affiliation and control combined in ways other than complementarity-mostly additively, but sometimes synergistically-to predict negative affect and relationship satisfaction.

  10. Affiliation and control in marital interaction: interpersonal complementarity is present but is not associated with affect or relationship quality.

    Science.gov (United States)

    Cundiff, Jenny M; Smith, Timothy W; Butner, Jonathan; Critchfield, Kenneth L; Nealey-Moore, Jill

    2015-01-01

    The principle of complementarity in interpersonal theory states that an actor's behavior tends to "pull, elicit, invite, or evoke" responses from interaction partners who are similar in affiliation (i.e., warmth vs. hostility) and opposite in control (i.e., dominance vs. submissiveness). Furthermore, complementary interactions are proposed to evoke less negative affect and promote greater relationship satisfaction. These predictions were examined in two studies of married couples. Results suggest that complementarity in affiliation describes a robust general pattern of marital interaction, but complementarity in control varies across contexts. Consistent with behavioral models of marital interaction, greater levels of affiliation and lower control by partners-not complementarity in affiliation or control-were associated with less anger and anxiety and greater relationship quality. Partners' levels of affiliation and control combined in ways other than complementarity-mostly additively, but sometimes synergistically-to predict negative affect and relationship satisfaction. PMID:25367005

  11. Quaternary structure of the ATPase complex of human 26S proteasomes determined by chemical cross-linking

    DEFF Research Database (Denmark)

    Hartmann-Petersen, R; Tanaka, K; Hendil, K B

    2001-01-01

    -linking, immunoprecipitation, and blotting, we have determined that the ATPases are organized in the order S6-S6'-S10b-S8-S4-S7. Additionally, we found cross-links between the ATPase S10b and the 20S proteasome subunit alpha6. Together with the previously known interaction between S8 and alpha1 and between S4 and alpha7...

  12. The ubiquitin–proteasome system as a molecular target in solid tumors: an update on bortezomib

    OpenAIRE

    Caponigro, Francesco

    2009-01-01

    A Milano,1 F Perri,2 F Caponigro21Sandro Pitigliani Medical Oncology Unit, Department of Oncology, Hospital of Prato, Istituto Toscano Tumori, Prato, Italy; 2Head and Neck Medical Oncology Unit, National Tumour institute of Naples, Naples, ItalyAbstract: The ubiquitin–proteasome system has become a promising molecular target in cancer therapy due to its critical role in cellular protein degradation, interaction with cell cycle and apoptosis regulation, and unique mechanism of action...

  13. BOR-syndrome-associated Eya1 mutations lead to enhanced proteasomal degradation of Eya1 protein.

    Directory of Open Access Journals (Sweden)

    Amna Musharraf

    Full Text Available Mutations in the human EYA1 gene have been associated with several human diseases including branchio-oto (BO and branchio-oto-renal (BOR syndrome, as well as congenital cataracts and ocular anterior segment anomalies. BOR patients suffer from severe malformations of the ears, branchial arches and kidneys. The phenotype of Eya1-heterozygous mice resembles the symptoms of human patients suffering from BOR syndrome. The Eya1 gene encodes a multifunctional protein that acts as a protein tyrosine phosphatase and a transcriptional coactivator. It has been shown that Eya1 interacts with Six transcription factors, which are also required for nuclear translocation of the Eya1 protein. We investigated the effects of seven disease-causing Eya1 missense mutations on Eya1 protein function, in particular cellular localization, ability to interact with Six proteins, and protein stability. We show here that the BOR-associated Eya1 missense mutations S454P, L472R, and L550P lead to enhanced proteasomal degradation of the Eya1 protein in mammalian cells. Moreover, Six proteins lead to a significant stabilization of Eya1, which is caused by Six-mediated protection from proteasomal degradation. In case of the mutant L550P, loss of interaction with Six proteins leads to rapid protein degradation. Our observations suggest that protein destabilization constitutes a novel disease causing mechanism for Eya1.

  14. Interaction between Hsp60 and Bax in normal human myocardium and in myocardium affected by dilated cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Tykhonkova I. O.

    2009-04-01

    Full Text Available The main functional compartments of molecular chaperone Hsp60 are mitochondria and cytoplasm. Up to 30 % of Hsp60 are located in cytoplasm of cardiomyocytes. The interaction between molecular chaperone Hsp60 and proapoptotic Bax protein in the cytoplasmic fraction from normal human heart tissue has been revealed by co-immunoprecipitation in contrast to myocardium affected by dilated cardiomyopathy, where this interaction has not been observed

  15. Social Requests and Social Affordances: How They Affect the Kinematics of Motor Sequences during Interactions between Conspecifics

    OpenAIRE

    Francesca Ferri; Giovanna Cristina Campione; Riccardo Dalla Volta; Claudia Gianelli; Maurizio Gentilucci

    2011-01-01

    The present study aimed at determining whether and what factors affect the control of motor sequences related to interactions between conspecifics. Experiment 1 demonstrated that during interactions between conspecifics guided by the social intention of feeding, a social affordance was activated, which modified the kinematics of sequences constituted by reaching-grasping and placing. This was relative to the same sequence directed to an inanimate target. Experiments 2 and 4 suggested that the...

  16. Prostate stem cell antigen interacts with nicotinic acetylcholine receptors and is affected in Alzheimer's disease.

    Science.gov (United States)

    Jensen, Majbrit M; Arvaniti, Maria; Mikkelsen, Jens D; Michalski, Dominik; Pinborg, Lars H; Härtig, Wolfgang; Thomsen, Morten S

    2015-04-01

    Alzheimer's disease (AD) is a neurodegenerative disorder involving impaired cholinergic neurotransmission and dysregulation of nicotinic acetylcholine receptors (nAChRs). Ly-6/neurotoxin (Lynx) proteins have been shown to modulate cognition and neural plasticity by binding to nAChR subtypes and modulating their function. Hence, changes in nAChR regulatory proteins such as Lynx proteins could underlie the dysregulation of nAChRs in AD. Using Western blotting, we detected bands corresponding to the Lynx proteins prostate stem cell antigen (PSCA) and Lypd6 in human cortex indicating that both proteins are present in the human brain. We further showed that PSCA forms stable complexes with the α4 nAChR subunit and decreases nicotine-induced extracellular-signal regulated kinase phosphorylation in PC12 cells. In addition, we analyzed protein levels of PSCA and Lypd6 in postmortem tissue of medial frontal gyrus from AD patients and found significantly increased PSCA levels (approximately 70%). In contrast, no changes in Lypd6 levels were detected. In concordance with our findings in AD patients, PSCA levels were increased in the frontal cortex of triple transgenic mice with an AD-like pathology harboring human transgenes that cause both age-dependent β-amyloidosis and tauopathy, whereas Tg2576 mice, which display β-amyloidosis only, had unchanged PSCA levels compared to wild-type animals. These findings identify PSCA as a nAChR-binding protein in the human brain that is affected in AD, suggesting that PSCA-nAChR interactions may be involved in the cognitive dysfunction observed in AD. PMID:25680266

  17. The Proteasome Inhibitor MG-132 Protects Hypoxic SiHa Cervical Carcinoma Cells after Cyclic Hypoxia/Reoxygenation from Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Frank Pajonk

    2006-12-01

    Full Text Available INTRODUCTION: Transient hypoxia and subsequent reoxygenation are common phenomena in solid tumors that greatly influence the outcome of radiation therapy. This study was designed to determine how varying cycles of hypoxia/reoxygenation affect the response of cervical carcinoma cells irradiated under oxic and hypoxic conditions and whether this could be modulated by proteasome inhibition. MATERIALS AND METHODS: Plateau-phase SiHa cervical carcinoma cells in culture were exposed to varying numbers of 30-minute cycles of hypoxia/reoxygenation directly before irradiation under oxic or hypoxic conditions. 26S Proteasome activity was blocked by addition of MG-132. Clonogenic survival was measured by a colonyforming assay. RESULTS: Under oxic conditions, repeated cycles of hypoxia/reoxygenation decreased the clonogenic survival of SiHa cells. This effect was even more pronounced after the inhibition of 26S proteasome complex. In contrast, under hypoxic conditions, SiHa cells were radioresistant, as expected, but this was increased by proteasome inhibition. CONCLUSIONS: Proteasome inhibition radiosensitizes oxygenated tumor cells but may also protect tumor cells from ionizing radiation under certain hypoxic conditions.

  18. Changes in proteasome structure and function caused by HAMLET in tumor cells.

    OpenAIRE

    Lotta Gustafsson; Sonja Aits; Patrik Onnerfjord; Maria Trulsson; Petter Storm; Catharina Svanborg

    2009-01-01

    BACKGROUND: Proteasomes control the level of endogenous unfolded proteins by degrading them in the proteolytic core. Insufficient degradation due to altered protein structure or proteasome inhibition may trigger cell death. This study examined the proteasome response to HAMLET, a partially unfolded protein-lipid complex, which is internalized by tumor cells and triggers cell death. METHODOLOGY/PRINCIPAL FINDINGS: HAMLET bound directly to isolated 20S proteasomes in vitro and in tumor cells si...

  19. Validation of the 2nd Generation Proteasome Inhibitor Oprozomib for Local Therapy of Pulmonary Fibrosis

    OpenAIRE

    Semren, Nora; Habel-Ungewitter, Nunja C.; Fernandez, Isis E.; Königshoff, Melanie; Eickelberg, Oliver; Stöger, Tobias; Meiners, Silke

    2015-01-01

    Proteasome inhibition has been shown to prevent development of fibrosis in several organs including the lung. However, effects of proteasome inhibitors on lung fibrosis are controversial and cytotoxic side effects of the overall inhibition of proteasomal protein degradation cannot be excluded. Therefore, we hypothesized that local lung-specific application of a novel, selective proteasome inhibitor, oprozomib (OZ), provides antifibrotic effects without systemic toxicity in a mouse model of lu...

  20. Failure of Amino Acid Homeostasis Causes Cell Death following Proteasome Inhibition

    OpenAIRE

    Suraweera, Amila; Münch, Christian; Hanssum, Ariane; Bertolotti, Anne

    2012-01-01

    Summary The ubiquitin-proteasome system targets many cellular proteins for degradation and thereby controls most cellular processes. Although it is well established that proteasome inhibition is lethal, the underlying mechanism is unknown. Here, we show that proteasome inhibition results in a lethal amino acid shortage. In yeast, mammalian cells, and flies, the deleterious consequences of proteasome inhibition are rescued by amino acid supplementation. In all three systems, this rescuing effe...

  1. A Possible Mechanism of the Impact of Atmosphere-Ocean Interaction on the Activity of Tropical Cyclones Affecting China

    Institute of Scientific and Technical Information of China (English)

    REN Fumin; BAI Lina; WU Guoxiong; WANG Zaizhi; WANG Yuan

    2012-01-01

    In this study,tropical cyclone data from China Meteorological Administration (CMA) and the ECMWF reanalysis data for the period 1958 2001 was used to propose a possible mechanism for the impacts of airsea interaction on the activity of tropical cyclones (TCs) affecting China.The frequency of TCs affecting China over past 40 years has trended downward,while during the same period,the air sea interaction in the two key areas of the Pacific region has significantly weakened.Our diagnoses and simulations suggest that air sea interactions in the central North Pacific tropics and subtropics (Area 1) have an important role in adjusting typhoon activities in the Northwest Pacific in general,and especially in TC activity affecting China.On the contrary,impacts of the air-sea interaction in the eastern part of the South Pacific tropics (Area 2) were found to be rather limited.As both observational analysis and modeling studies show that,in the past four decades and beyond,the weakening trend of the latent heat released from Area 1 matched well with the decreasing Northwest Pacific TC frequency derived from CMA datasets.Results also showed that the weakening trend of latent heat flux in the area was most likely due to the decreasing TC frequency over the Northwest Pacific,including those affecting China.Although our preliminary analysis revealed a possible mechanism through which the air sea interaction may adjust the genesis conditions for TCs,which eventually affect China,other relevant questions,such as how TC tracks and impacts are affected by these trends,remain unanswered.Further in-depth investigations are required.

  2. Structural analysis of the 26S proteasome by cryoelectron tomography.

    Science.gov (United States)

    Nickell, Stephan; Mihalache, Oana; Beck, Florian; Hegerl, Reiner; Korinek, Andreas; Baumeister, Wolfgang

    2007-02-01

    The 26S proteasome is the key enzyme of intracellular protein degradation in eukaryotic cells. It is a multisubunit complex of 2.5 MDa confining the proteolytic action to an inner compartment with tightly controlled access. Structural studies of this intriguing molecular machine have been hampered by its intrinsic instability and its dynamics. Here we have used an unconventional approach to obtain a three-dimensional structure of the holocomplex uncompromised by preparation-induced alterations and unbiased by any starting model. We have performed a tomographic reconstruction, followed by averaging over approx. 150 individual reconstructions, of Drosophila 26S proteasomes suspended in a thin layer of amorphous ice.

  3. A heterodimeric complex that promotes the assembly of mammalian 20S proteasomes

    DEFF Research Database (Denmark)

    Hirano, Yoko; Hendil, Klavs B.; Yashiroda, Hideki;

    2005-01-01

    The 26S proteasome is a multisubunit protease responsible for regulated proteolysis in eukaryotic cells 1, 2 . It comprises one catalytic 20S proteasome and two axially positioned 19S regulatory complexes 3 . The 20S proteasome is composed of 28 subunits arranged in a cylindrical particle as four...

  4. Alteration of Proteasome System in Aging and Aging-Associated Disorders

    Directory of Open Access Journals (Sweden)

    Qunxing Ding

    2015-11-01

    Full Text Available The proteasome system is crucial in protein metabolism involving in physiological and pathological developments, especially in aging and agingrelated disorders. Here we discussed the relationship of proteasome with other metabolic systems such as lysosome and ribosome as well as the alteration of proteasome system under oxidative stress, aging and other pathological conditions

  5. Genotype-environment interactions affecting preflowering physiological and morphological traits of Brassica rapa grown in two watering regimes

    NARCIS (Netherlands)

    El-Soda, M.; Boer, M.P.; Bagheri, H.; Hanhart, C.J.; Koornneef, M.; Aarts, M.G.M.

    2014-01-01

    Plant growth and productivity are greatly affected by drought, which is likely to become more threatening with the predicted global temperature increase. Understanding the genetic architecture of complex quantitative traits and their interaction with water availability may lead to improved crop adap

  6. Do Core Interpersonal and Affective Traits of PCL-R Psychopathy Interact with Antisocial Behavior and Disinhibition to Predict Violence?

    Science.gov (United States)

    Kennealy, Patrick J.; Skeem, Jennifer L.; Walters, Glenn D.; Camp, Jacqueline

    2010-01-01

    The utility of psychopathy measures in predicting violence is largely explained by their assessment of social deviance (e.g., antisocial behavior; disinhibition). A key question is whether social deviance "interacts" with the core interpersonal-affective traits of psychopathy to predict violence. Do core psychopathic traits multiply the (already…

  7. The influence of prejudice and stereotypes on anticipated affect : feelings about a potentially negative interaction with another ethnic group

    NARCIS (Netherlands)

    Gordijn, Ernestine; Finchilescu, Gillian; Brix, Louise; Wijnants, Nienke; Koomen, Willem

    2008-01-01

    In this research we investigated whether feelings about an imagined potentially negative interaction with a member of another ethnic group was affected more by valence than content of stereotypes, and whether the differential influence of perception and meta-perception was similar for dominant and d

  8. The Xanthomonas campestris type III effector XopJ targets the host cell proteasome to suppress salicylic-acid mediated plant defence.

    Directory of Open Access Journals (Sweden)

    Suayib Üstün

    Full Text Available The phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv requires type III effector proteins (T3Es for virulence. After translocation into the host cell, T3Es are thought to interact with components of host immunity to suppress defence responses. XopJ is a T3E protein from Xcv that interferes with plant immune responses; however, its host cellular target is unknown. Here we show that XopJ interacts with the proteasomal subunit RPT6 in yeast and in planta to inhibit proteasome activity. A C235A mutation within the catalytic triad of XopJ as well as a G2A exchange within the N-terminal myristoylation motif abolishes the ability of XopJ to inhibit the proteasome. Xcv ΔxopJ mutants are impaired in growth and display accelerated symptom development including tissue necrosis on susceptible pepper leaves. Application of the proteasome inhibitor MG132 restored the ability of the Xcv ΔxopJ to attenuate the development of leaf necrosis. The XopJ dependent delay of tissue degeneration correlates with reduced levels of salicylic acid (SA and changes in defence- and senescence-associated gene expression. Necrosis upon infection with Xcv ΔxopJ was greatly reduced in pepper plants with reduced expression of NPR1, a central regulator of SA responses, demonstrating the involvement of SA-signalling in the development of XopJ dependent phenotypes. Our results suggest that XopJ-mediated inhibition of the proteasome interferes with SA-dependent defence response to attenuate onset of necrosis and to alter host transcription. A central role of the proteasome in plant defence is discussed.

  9. Childhood depression and conduct disorder: I. Behavioral, affective, and cognitive aspects of family problem-solving interactions.

    Science.gov (United States)

    Sanders, M R; Dadds, M R; Johnston, B M; Cash, R

    1992-08-01

    We assessed the family interactions of depressed, conduct-disordered, mixed depressed-conduct-disordered, and nonclinic children, ages 7-14 years, during a standardized family problem-solving discussion in the clinic. The child's and the mother's problem-solving proficiency, aversive behavior, and associated affective behavior (depressed and angry-hostile) were observed. The child and mother also rated each other's affect during the interaction for the dimensions sad, angry, critical, and happy on Likert-type scales. The child's and mother's cognitive constructions about the interaction were assessed using video-mediated recall. Although all clinic groups had lower levels of effective problem solving than did nonclinic children, their deficiencies were somewhat different. Mixed and depressed children displayed high levels of depressed affect and low levels of angry affect, whereas conduct-disordered children displayed both angry and depressed affect. In addition, conduct-disordered children had lower levels of positive problem solving and higher levels of aversive content than did non-conduct-disordered children. Depressed and conduct-disordered children had higher levels of self-referent negative cognitions than did mixed and comparison children, and depressed children also had higher other-referent negative cognitions than did all other groups. The study provides support for theories and treatment that stress the importance of family problem-solving and conflict resolution skills in child psychopathology.

  10. Predicting the Accuracy of Facial Affect Recognition: The Interaction of Child Maltreatment and Intellectual Functioning

    Science.gov (United States)

    Shenk, Chad E.; Putnam, Frank W.; Noll, Jennie G.

    2013-01-01

    Previous research demonstrates that both child maltreatment and intellectual performance contribute uniquely to the accurate identification of facial affect by children and adolescents. The purpose of this study was to extend this research by examining whether child maltreatment affects the accuracy of facial recognition differently at varying…

  11. Is Infant Initiation of Joint Attention by Pointing Affected by Type of Interaction?

    Science.gov (United States)

    Franco, Fabia; Perucchini, Paola; March, Barbara

    2009-01-01

    This article reports the results of two experiments studying the effects of type of interaction on infant production of declarative pointing. In Experiment 1, intensity of social presence was manipulated in adult-infant interaction with 12-19-month-olds (no social presence; adult responding only; adult also initiating joint attentional bids).…

  12. Proteasome function shapes innate and adaptive immune responses.

    Science.gov (United States)

    Kammerl, Ilona E; Meiners, Silke

    2016-08-01

    The proteasome system degrades more than 80% of intracellular proteins into small peptides. Accordingly, the proteasome is involved in many essential cellular functions, such as protein quality control, transcription, immune responses, cell signaling, and apoptosis. Moreover, degradation products are loaded onto major histocompatibility class I molecules to communicate the intracellular protein composition to the immune system. The standard 20S proteasome core complex contains three distinct catalytic active sites that are exchanged upon stimulation with inflammatory cytokines to form the so-called immunoproteasome. Immunoproteasomes are constitutively expressed in immune cells and have different proteolytic activities compared with standard proteasomes. They are rapidly induced in parenchymal cells upon intracellular pathogen infection and are crucial for priming effective CD8(+) T-cell-mediated immune responses against infected cells. Beyond shaping these adaptive immune reactions, immunoproteasomes also regulate the function of immune cells by degradation of inflammatory and immune mediators. Accordingly, they emerge as novel regulators of innate immune responses. The recently unraveled impairment of immunoproteasome function by environmental challenges and by genetic variations of immunoproteasome genes might represent a currently underestimated risk factor for the development and progression of lung diseases. In particular, immunoproteasome dysfunction will dampen resolution of infections, thereby promoting exacerbations, may foster autoimmunity in chronic lung diseases, and possibly contributes to immune evasion of tumor cells. Novel pharmacological tools, such as site-specific inhibitors of the immunoproteasome, as well as activity-based probes, however, hold promises as innovative therapeutic drugs for respiratory diseases and biomarker profiling, respectively. PMID:27343191

  13. The Ubiquitin-Proteasome Pathway and Synaptic Plasticity

    Science.gov (United States)

    Hegde, Ashok N.

    2010-01-01

    Proteolysis by the ubiquitin-proteasome pathway (UPP) has emerged as a new molecular mechanism that controls wide-ranging functions in the nervous system, including fine-tuning of synaptic connections during development and synaptic plasticity in the adult organism. In the UPP, attachment of a small protein, ubiquitin, tags the substrates for…

  14. Nicotiana tabacum Tsip1-Interacting Ferredoxin 1 Affects Biotic and Abiotic Stress Resistance

    OpenAIRE

    Huh, Sung Un; Lee, In-Ju; Ham, Byung-Kook; Paek, Kyung-Hee

    2012-01-01

    Tsip1, a Zn finger protein that was isolated as a direct interactor with tobacco stress-induced 1 (Tsi1), plays an important role in both biotic and abiotic stress signaling. To further understand Tsip1 function, we searched for more Tsip1-interacting proteins by yeast two-hybrid screening using a tobacco cDNA library. Screening identified a new Tsip1-interacting protein, Nicotiana tabacum Tsip1-interacting ferredoxin 1 (NtTfd1), and binding specificity was confirmed both in vitro and in vivo...

  15. PARO robot affects diverse interaction modalities in group sensory therapy for older adults with dementia.

    Science.gov (United States)

    Šabanović, Selma; Bennett, Casey C; Chang, Wan-Ling; Huber, Lesa

    2013-06-01

    We evaluated the seal-like robot PARO in the context of multi-sensory behavioral therapy in a local nursing home. Participants were 10 elderly nursing home residents with varying levels of dementia. We report three principle findings from our observations of interactions between the residents, PARO, and a therapist during seven weekly therapy sessions. Firstly, we show PARO provides indirect benefits for users by increasing their activity in particular modalities of social interaction, including visual, verbal, and physical interaction, which vary between primary and non-primary interactors. Secondly, PARO's positive effects on older adults' activity levels show steady growth over the duration of our study, suggesting they are not due to short-term "novelty effects." Finally, we show a variety of ways in which individual participants interacted with PARO and relate this to the "interpretive flexibility" of its design.

  16. Affect-modulated startle: interactive influence of catechol-O-methyltransferase Val158Met genotype and childhood trauma.

    Science.gov (United States)

    Klauke, Benedikt; Winter, Bernward; Gajewska, Agnes; Zwanzger, Peter; Reif, Andreas; Herrmann, Martin J; Dlugos, Andrea; Warrings, Bodo; Jacob, Christian; Mühlberger, Andreas; Arolt, Volker; Pauli, Paul; Deckert, Jürgen; Domschke, Katharina

    2012-01-01

    The etiology of emotion-related disorders such as anxiety or affective disorders is considered to be complex with an interaction of biological and environmental factors. Particular evidence has accumulated for alterations in the dopaminergic and noradrenergic system--partly conferred by catechol-O-methyltransferase (COMT) gene variation--for the adenosinergic system as well as for early life trauma to constitute risk factors for those conditions. Applying a multi-level approach, in a sample of 95 healthy adults, we investigated effects of the functional COMT Val158Met polymorphism, caffeine as an adenosine A2A receptor antagonist (300 mg in a placebo-controlled intervention design) and childhood maltreatment (CTQ) as well as their interaction on the affect-modulated startle response as a neurobiologically founded defensive reflex potentially related to fear- and distress-related disorders. COMT val/val genotype significantly increased startle magnitude in response to unpleasant stimuli, while met/met homozygotes showed a blunted startle response to aversive pictures. Furthermore, significant gene-environment interaction of COMT Val158Met genotype with CTQ was discerned with more maltreatment being associated with higher startle potentiation in val/val subjects but not in met carriers. No main effect of or interaction effects with caffeine were observed. Results indicate a main as well as a GxE effect of the COMT Val158Met variant and childhood maltreatment on the affect-modulated startle reflex, supporting a complex pathogenetic model of the affect-modulated startle reflex as a basic neurobiological defensive reflex potentially related to anxiety and affective disorders.

  17. Affect-modulated startle: interactive influence of catechol-O-methyltransferase Val158Met genotype and childhood trauma.

    Directory of Open Access Journals (Sweden)

    Benedikt Klauke

    Full Text Available The etiology of emotion-related disorders such as anxiety or affective disorders is considered to be complex with an interaction of biological and environmental factors. Particular evidence has accumulated for alterations in the dopaminergic and noradrenergic system--partly conferred by catechol-O-methyltransferase (COMT gene variation--for the adenosinergic system as well as for early life trauma to constitute risk factors for those conditions. Applying a multi-level approach, in a sample of 95 healthy adults, we investigated effects of the functional COMT Val158Met polymorphism, caffeine as an adenosine A2A receptor antagonist (300 mg in a placebo-controlled intervention design and childhood maltreatment (CTQ as well as their interaction on the affect-modulated startle response as a neurobiologically founded defensive reflex potentially related to fear- and distress-related disorders. COMT val/val genotype significantly increased startle magnitude in response to unpleasant stimuli, while met/met homozygotes showed a blunted startle response to aversive pictures. Furthermore, significant gene-environment interaction of COMT Val158Met genotype with CTQ was discerned with more maltreatment being associated with higher startle potentiation in val/val subjects but not in met carriers. No main effect of or interaction effects with caffeine were observed. Results indicate a main as well as a GxE effect of the COMT Val158Met variant and childhood maltreatment on the affect-modulated startle reflex, supporting a complex pathogenetic model of the affect-modulated startle reflex as a basic neurobiological defensive reflex potentially related to anxiety and affective disorders.

  18. Interactive effect of negative affectivity and anxiety sensitivity in terms of mental health among Latinos in primary care.

    Science.gov (United States)

    Zvolensky, Michael J; Paulus, Daniel J; Bakhshaie, Jafar; Garza, Monica; Ochoa-Perez, Melissa; Medvedeva, Angela; Bogiaizian, Daniel; Robles, Zuzuky; Manning, Kara; Schmidt, Norman B

    2016-09-30

    From a public health perspective, primary care medical settings represent a strategic location to address mental health disapirty among Latinos. Yet, there is little empirical work that addresses affective vulnerability processes for mental health problems in such settings. To help address this gap in knowledge, the present investigation examined an interactive model of negative affectivity (tendency to experience negative mood states) and anxiety sensitivity (fear of the negative consequences of aversive sensations) among a Latino sample in primary care in terms of a relatively wide range of anxiety/depression indices. Participants included 390 Latino adults (Mage=38.7, SD=11.3; 86.9% female; 95.6% reported Spanish as first language) from a primary care health clinic. Primary dependent measures included depressive, suicidal, social anxiety, and anxious arousal symptoms, number of mood and anxiety disorders, and disability. Consistent with prediction, the interaction between negative affectivity and anxiety sensitivity was significantly related to suicidal, social anxiety, and anxious arousal symptoms, as well as number of mood/anxiety diagnoses and disability among the primary care Latino sample. The form of the interactions indicated a synergistic effect, such that the greatest levels of each outcome were found among those with high negative affectivity and high anxiety sensitivity. There was a trending interaction for depressive symptoms. Overall, these data provide novel empirical evidence suggesting that there is a clinically-relevant interplay between anxiety sensitivity and negative affectivity in regard to the expression of anxiety and depressive symptoms among a Latino primary care sample. PMID:27359301

  19. Designing finger touch gestures for affective and expressive interaction on mobile social networking sites

    OpenAIRE

    Amoor Pour, Sepehr

    2014-01-01

    This thesis project is an interaction design study, which studies how finger touch gestures can be used as expressive alternatives to text comments on social networking sites. In the study qualitative research methods and a user-centred approach are used. The study collects literature on how emotion is modeled in Human-computer Interaction and how emotion can be expressed through touch. The popular social networking site Facebook is used as a case study of user behavior on social networking s...

  20. Hydroxyl Density Affects the Interaction of Fibrinogen with Silica Nanoparticles at Physiological Concentration

    OpenAIRE

    Marucco, Arianna; Turci, Francesco; O'Neill, Luke; Byrne, Hugh; Fubini, Bice; Fenoglio, Ivana

    2013-01-01

    An increasing interest in the interaction between blood serum proteins and nanoparticles has emerged over the last years. In fact, this process plays a key role in the biological response to nanoparticles. The behavior of proteins at the biofluid/material interface is driven by the physico-chemical properties of the surface. However, much research is still needed to gain insight into the process at a molecular level. In this study, the effect of silanol density on the interaction of fibrinog...

  1. Proteasome nuclear import mediated by Arc3 can influence efficient DNA damage repair and mitosis in Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Cabrera, Rodrigo; Sha, Zhe; Vadakkan, Tegy J.;

    2010-01-01

    Proteasomes must remove regulatory molecules and abnormal proteins throughout the cell, but how proteasomes can do so efficiently remains unclear. We have isolated a subunit of the Arp2/3 complex, Arc3, which binds proteasomes. When overexpressed, Arc3 rescues phenotypes associated with proteasom...

  2. The environment affects epistatic interactions to alter the topology of an empirical fitness landscape.

    Directory of Open Access Journals (Sweden)

    Kenneth M Flynn

    2013-04-01

    Full Text Available The fitness effect of mutations can be influenced by their interactions with the environment, other mutations, or both. Previously, we constructed 32 ( = 2⁵ genotypes that comprise all possible combinations of the first five beneficial mutations to fix in a laboratory-evolved population of Escherichia coli. We found that (i all five mutations were beneficial for the background on which they occurred; (ii interactions between mutations drove a diminishing returns type epistasis, whereby epistasis became increasingly antagonistic as the expected fitness of a genotype increased; and (iii the adaptive landscape revealed by the mutation combinations was smooth, having a single global fitness peak. Here we examine how the environment influences epistasis by determining the interactions between the same mutations in two alternative environments, selected from among 1,920 screened environments, that produced the largest increase or decrease in fitness of the most derived genotype. Some general features of the interactions were consistent: mutations tended to remain beneficial and the overall pattern of epistasis was of diminishing returns. Other features depended on the environment; in particular, several mutations were deleterious when added to specific genotypes, indicating the presence of antagonistic interactions that were absent in the original selection environment. Antagonism was not caused by consistent pleiotropic effects of individual mutations but rather by changing interactions between mutations. Our results demonstrate that understanding adaptation in changing environments will require consideration of the combined effect of epistasis and pleiotropy across environments.

  3. The role of the proteasome for therapy of incurable diseases

    Directory of Open Access Journals (Sweden)

    Irena Bubko

    2010-07-01

    Full Text Available Proteins constitute the basic building elements of living organisms. Proteins have a limited lifetime in a cell. The so called “half-life period” of proteins is diverse and lasts from several minutes to several days. Regulatory proteins appear in a cell for a definite time and are short-lived. The proteins responsible for basic cell functions are stable and long-lived. Once their functions are fulfilled or because of their surfeit or damage, proteins are eliminated by degradation. Transformation processes of proteins are precisely controlled. There is also a strict association between protein metabolism and the energetic state of a cell. The main proteolytic cell systems are lysosomal and proteasome ones. The first (lysosomes function in a simple and transparent way. The second system (proteasomes is highly organized; by using ubiquitin it delivers “molecular label” and sends a marked protein for degradation. Efficient degradation of cellular proteins by the UPS route (ubiquitin – proteasome system is essential for signal transduction, transcription adjustment, response to stress and control of receptors’ activity. The dysfunction of the UPS route is crucial in the development of tumors, neurodegenerative diseases and diseases of immunological and infectious origin. Therefore, it is a challenge to elaborate methods of pharmacological intervention within this system involving, for example, the use of specific, low molecular-weight proteasome inhibitors and enzymes catalyzing the ubiquitination process. The article presents a review of advances in the field, including description of the lysosomal protein degradation route, proteasome model, and the phenomenon of protein aggregation. The summary of the experience on applied therapies, which use the processes of protein degradation as a basis, were also presented.

  4. From facilitation to competition: temperature-driven shift in dominant plant interactions affects population dynamics in seminatural grasslands.

    Science.gov (United States)

    Olsen, Siri L; Töpper, Joachim P; Skarpaas, Olav; Vandvik, Vigdis; Klanderud, Kari

    2016-05-01

    Biotic interactions are often ignored in assessments of climate change impacts. However, climate-related changes in species interactions, often mediated through increased dominance of certain species or functional groups, may have important implications for how species respond to climate warming and altered precipitation patterns. We examined how a dominant plant functional group affected the population dynamics of four co-occurring forb species by experimentally removing graminoids in seminatural grasslands. Specifically, we explored how the interaction between dominants and subordinates varied with climate by replicating the removal experiment across a climate grid consisting of 12 field sites spanning broad-scale temperature and precipitation gradients in southern Norway. Biotic interactions affected population growth rates of all study species, and the net outcome of interactions between dominants and subordinates switched from facilitation to competition with increasing temperature along the temperature gradient. The impacts of competitive interactions on subordinates in the warmer sites could primarily be attributed to reduced plant survival. Whereas the response to dominant removal varied with temperature, there was no overall effect of precipitation on the balance between competition and facilitation. Our findings suggest that global warming may increase the relative importance of competitive interactions in seminatural grasslands across a wide range of precipitation levels, thereby favouring highly competitive dominant species over subordinate species. As a result, seminatural grasslands may become increasingly dependent on disturbance (i.e. traditional management such as grazing and mowing) to maintain viable populations of subordinate species and thereby biodiversity under future climates. Our study highlights the importance of population-level studies replicated under different climatic conditions for understanding the underlying mechanisms of climate

  5. Expression change of Nicastrin in the neuronal cells and its relationship with Aβ generation after proteasomal inhibitor treatment%蛋白酶体抑制剂处理神经细胞系后Nicastrin的表达变化及其与Aβ的关系

    Institute of Scientific and Technical Information of China (English)

    龙志敏; 赵蕾; 骆世芳; 汪克建; 贺桂琼

    2011-01-01

    Objective To explore whether Nicastrin undergoes ubiquitination before proteasomal degradation, as well as the relationship between Nicastrin protein level and Aβ generation. Methods Cell fractionation, Western blot, immunoprecipitation as well as ELISA were used to check the expression of NCT and Aβ level. Results NCr distributes primarily in ER and Golgi apparatus but less in lysosome. Increased NCT accumulates was found in the ER and Golgi apparatus after proteasomal inhibition. NCT and ubiquitin colocalized and interacted with each other in cells. The degradation of NCT was not affected by PS. Overexpression of NCT by transient NCT plasmid transfection or inhibition of NCT proteasomal degradation can decrease substrate of γ-secretase, C99 and C83, and increase production of γ-secretase, Aβ40 and Aβ42( P <0.01 ). Conclusion The degradation of NCT is resulted from ubiquitin-proteasome pathway. The expression of NCT is increased following proteasomal inhibition, and over-expression of NCT facilitates APP processing and Aβ generation.%目的 探讨蛋白酶体抑制剂处理后神经细胞内Nicastrin(NCT)的表达变化,及其与γ-分泌酶活性和Aβ生成的关系.方法 运用亚细胞器分级分离技术、免疫共沉淀、Western blot和ELISA等检测神经细胞内NCT的表达及Aβ水平.结果 正常情况下NCT主要分布于内质网和高尔基复合体,极少量分布于溶酶体,蛋白酶体抑制剂Lactacystin处理后NCT水平升高(P<0.001),且细胞内增多的NCT也主要聚集在内质网和高尔基复合体;NCT与泛素在细胞内共存;NCT的蛋白降解不受PS的影响;NCT降解受阻可引起细胞内γ-分泌酶的底物C99、C83显著减少,而γ-分泌酶的产物Aβ40、Aβ42的生成显著增多(P<0.01).结论 NCT的降解可通过泛素-蛋白酶体途径实现,蛋白酶体抑制剂处理后神经细胞内NCT水平升高,且增多的NCT可促进APP的代谢及Aβ的生成.

  6. [Maternal affect regulation of mothers with a history of abuse in mother-infant-interaction].

    Science.gov (United States)

    Kress, Sandra; Cierpka, Manfred; Möhler, Eva; Resch, Franz

    2012-01-01

    Maternal intuitive skills can be threatened as a result of severe deprivation or unresolved trauma in the own childhood and can even be inaccessible to the mother. A mother's own childhood experience of abuse maybe a risk factor for repeated child abuse. As a follow-up study to assess the emotional availability of abused mothers it was investigated how a physical or sexual abuse appears in the mother-child interaction and communication in the context of "cycle of abuse" and whether it could give effect to it. Interactions of mothers with abuse experience were compared with those of mothers without an abuse experience and evaluated five months postpartum with the Munich clinical communication scale (MKK). The results suggest that maltreatment experienced mothers show less emotion tuning to their child in a standardized interaction sequence. PMID:22957399

  7. Contamination by uranium mine drainages affects fungal growth and interactions between fungal species and strains.

    Science.gov (United States)

    Ferreira, Verónica; Gonçalves, Ana Lúcia; Pratas, João; Canhoto, Cristina

    2010-01-01

    The presence of aquatic hyphomycetes has been reported for several heavy metal-contaminated waters. Tolerance probably is one adaptation to coping with heavy metals. To help clarify this issue strains of two species of aquatic hyphomycetes (Tricladium splendens Ingold and Varicosporium elodeae Kegel) were isolated from a reference stream and a stream contaminated with heavy metals and grown on malt extract agar prepared with reference and contaminated water to characterize colony morphology, growth rate, growth inhibition and interaction among species and strains. In V. elodeae the morphology of colonies differed between strains. Colony diameter increased linearly over time with growth rates being lower for strains isolated from contaminated than from reference streams (mostly for V. elodeae). Strains from the contaminated stream grew faster in medium prepared with contaminated water than in medium prepared with reference water, while for strains from the reference stream there was no significant difference in growth rates on the two media. In interacting isolates radial growth toward the opposing colony was generally lower than toward the dish edge. Percentage growth inhibition was higher for isolates in intraspecific interactions (13-37%) than in interspecific interactions (3-27%). However differences in growth inhibition experienced by interacting isolates were observed only in three cases out of 16. The difference between the percentage inhibition caused and experienced by a given isolate was highest in interactions involving isolates with distinct growth rates. Our results suggest that strains from the reference stream tolerate heavy metals while strains from the contaminated stream seem to be adapted to contaminated waters. We hypothesize that in natural environments fungal species-specific limits of tolerance to metal contamination might determine an abrupt or gradual response of the original fungal community to mine pollution giving origin to a poorer

  8. Prefoldin Promotes Proteasomal Degradation of Cytosolic Proteins with Missense Mutations by Maintaining Substrate Solubility.

    Directory of Open Access Journals (Sweden)

    Sophie A Comyn

    2016-07-01

    Full Text Available Misfolded proteins challenge the ability of cells to maintain protein homeostasis and can accumulate into toxic protein aggregates. As a consequence, cells have adopted a number of protein quality control pathways to prevent protein aggregation, promote protein folding, and target terminally misfolded proteins for degradation. In this study, we employed a thermosensitive allele of the yeast Guk1 guanylate kinase as a model misfolded protein to investigate degradative protein quality control pathways. We performed a flow cytometry based screen to identify factors that promote proteasomal degradation of proteins misfolded as the result of missense mutations. In addition to the E3 ubiquitin ligase Ubr1, we identified the prefoldin chaperone subunit Gim3 as an important quality control factor. Whereas the absence of GIM3 did not impair proteasomal function or the ubiquitination of the model substrate, it led to the accumulation of the poorly soluble model substrate in cellular inclusions that was accompanied by delayed degradation. We found that Gim3 interacted with the Guk1 mutant allele and propose that prefoldin promotes the degradation of the unstable model substrate by maintaining the solubility of the misfolded protein. We also demonstrated that in addition to the Guk1 mutant, prefoldin can stabilize other misfolded cytosolic proteins containing missense mutations.

  9. Prefoldin Promotes Proteasomal Degradation of Cytosolic Proteins with Missense Mutations by Maintaining Substrate Solubility.

    Science.gov (United States)

    Comyn, Sophie A; Young, Barry P; Loewen, Christopher J; Mayor, Thibault

    2016-07-01

    Misfolded proteins challenge the ability of cells to maintain protein homeostasis and can accumulate into toxic protein aggregates. As a consequence, cells have adopted a number of protein quality control pathways to prevent protein aggregation, promote protein folding, and target terminally misfolded proteins for degradation. In this study, we employed a thermosensitive allele of the yeast Guk1 guanylate kinase as a model misfolded protein to investigate degradative protein quality control pathways. We performed a flow cytometry based screen to identify factors that promote proteasomal degradation of proteins misfolded as the result of missense mutations. In addition to the E3 ubiquitin ligase Ubr1, we identified the prefoldin chaperone subunit Gim3 as an important quality control factor. Whereas the absence of GIM3 did not impair proteasomal function or the ubiquitination of the model substrate, it led to the accumulation of the poorly soluble model substrate in cellular inclusions that was accompanied by delayed degradation. We found that Gim3 interacted with the Guk1 mutant allele and propose that prefoldin promotes the degradation of the unstable model substrate by maintaining the solubility of the misfolded protein. We also demonstrated that in addition to the Guk1 mutant, prefoldin can stabilize other misfolded cytosolic proteins containing missense mutations. PMID:27448207

  10. Interactions between polymorphisms in the aryl hydrocarbon receptor signalling pathway and exposure to persistent organochlorine pollutants affect human semen quality

    DEFF Research Database (Denmark)

    Brokken, L J S; Lundberg, P J; Spanò, M;

    2014-01-01

    Persistent organic pollutants (POPs) may affect male reproductive function. Many dioxin-like POPs exert their effects by activation of the aryl hydrocarbon receptor (AHR) signalling pathway. We analysed whether gene-environment interactions between polymorphisms in AHR (R554K) and AHR repressor...... and the expression of the pro-apoptotic marker protein Fas. The data indicate that susceptibility to adverse effects of POP exposure on male reproductive function is dependent on polymorphisms in genes involved in AHR signalling....

  11. Proteasome dysfunction in Drosophila signals to an Nrf2-dependent regulatory circuit aiming to restore proteostasis and prevent premature aging

    OpenAIRE

    Tsakiri, Eleni N.; Sykiotis, Gerasimos P.; Papassideri, Issidora S.; Terpos, Evangelos; Dimopoulos, Meletios A; Gorgoulis, Vassilis G.; Bohmann, Dirk; Trougakos, Ioannis P.

    2013-01-01

    The ubiquitin–proteasome system is central to the regulation of cellular proteostasis. Nevertheless, the impact of in vivo proteasome dysfunction on the proteostasis networks and the aging processes remains poorly understood. We found that RNAi-mediated knockdown of 20S proteasome subunits in Drosophila melanogaster resulted in larval lethality. We therefore studied the molecular effects of proteasome dysfunction in adult flies by developing a model of dose-dependent pharmacological proteasom...

  12. Earthworm functional traits and interspecific interactions affect plant nitrogen acquisition and primary production

    NARCIS (Netherlands)

    Andriuzzi, Walter; Schmidt, Olaf; Brussaard, L.; Faber, J.H.; Bolger, T.

    2016-01-01

    We performed a greenhouse experiment to test how the functional diversity of earthworms, the dominant group of soil macro-invertebrates in many terrestrial ecosystems, affects nitrogen cycling and plant growth. Three species were chosen to represent a range of functional traits: Lumbricus terrestris

  13. Dietary interactions and interventions affecting Escherichia coli 0157 colonization and shedding in cattle

    Science.gov (United States)

    Escherichia coli O157 is an important foodborne pathogen affecting human health and the beef cattle industry. Contamination of carcasses at slaughter is correlated to the prevalence of E. coli O157 in cattle feces. Many associations have been made between dietary factors and E. coli O157 prevalenc...

  14. Calcium and protons affect the interaction of neurotransmitters and anesthetics with anionic lipid membranes.

    Science.gov (United States)

    Pérez-Isidoro, Rosendo; Ruiz-Suárez, J C

    2016-09-01

    We study how zwitterionic and anionic biomembrane models interact with neurotransmitters (NTs) and anesthetics (ATs) in the presence of Ca(2+) and different pH conditions. As NTs we used acetylcholine (ACh), γ-aminobutyric acid (GABA), and l-glutamic acid (LGlu). As ATs, tetracaine (TC), and pentobarbital (PB) were employed. By using differential scanning calorimetry (DSC), we analyzed the changes such molecules produce in the thermal properties of the membranes. We found that calcium and pH play important roles in the interactions of NTs and ATs with the anionic lipid membranes. Changes in pH promote deprotonation of the phosphate groups in anionic phospholipids inducing electrostatic interactions between them and NTs; but if Ca(2+) ions are in the system, these act as bridges. Such interactions impact the physical properties of the membranes in a similar manner that anesthetics do. Beyond the usual biochemical approach, we claim that these effects should be taken into account to understand the excitatory-inhibitory orchestrated balance in the nervous system. PMID:27362370

  15. The interaction between epiphytic algae, a parasitic fungus and Sphagnum as affected by N. and P.

    NARCIS (Netherlands)

    Limpens, J.; Jeffrey, T.A.G.; Baar, J.; Berendse, F.; Zijlstra, J.D.

    2003-01-01

    We report the effects of fertilisation with N and P on the infection of Sphagnum by its fungal parasite Lyophyllum palustre, the expansion of epiphytic algae and the interaction between the latter two from 1998 to 2001. We added 40 kg N ha(-1) yr(-1) or 3 kg P ha(-1) yr(-1) in a full factorial desig

  16. Higher-order interaction between molluscs and sheep affecting seedling numbers in grassland

    Science.gov (United States)

    Clear Hill, B. H.; Silvertown, J.

    Vertebrate and invertebrate herbivores are both important in mesotrophic grasslands and these two different classes of herbivore potentially interact in their effect upon plant populations. We used two field experiments to test for higher order interactions (HOIs) among sheep, slugs and seedlings, using the mechanistic definition that an HOI occurs when the presence of one species modifies the interaction between two others. In each experiment slug addition and slug-removal treatments were nested inside treatments that altered sheep grazing intensity and timing, and the emergence, of seedlings from experimentally sown seeds was monitored. In Experiment 1, seedling numbers of Cerastium fontanum were increased by intense summer grazing by sheep in both slug-addition and slugremoval treatment, but winter grazing by sheep only increased seedling emergence if slugs were removed. In Experiment 2, winter grazing by sheep significantly reduced total seedling emergence of four species sown ( Lotus corniculatus, Plantago lanceolata, Leucanthemum vulgare, Achillea millefolium), but the effect was only seen where slugs were removed. Though the experimental system is a relatively simple one with only four components (sheep, slugs, seedlings and the matrix vegetation), higher order interactions, a combination of direct and indirect effects and possible switching behaviour by slugs are all suggested by our results.

  17. Albumin Supplement Affects the Metabolism and Metabolism-Related Drug-Drug Interaction of Fenoprofen Enantiomers.

    Science.gov (United States)

    Wang, Nan; Wang, Feng; Meng, Yu; Yang, Guo-Hui; Chen, Ju-Wu; Wang, Jia-Xiang

    2015-07-01

    The influence of albumin towards the metabolism behavior of fenoprofen enantiomers and relevant drug-drug interaction was investigated in the present study. The metabolic behavior of fenoprofen enantiomers was compared in a phase II metabolic incubation system with and without bovine serum albumin (BSA). BSA supplement increased the binding affinity parameter (Km) of (R)-fenoprofen towards human liver microsomes (HLMs) from 148.3 to 214.4 μM. In contrast, BSA supplement decreased the Km of (S)-fenoprofen towards HLMs from 218.2 to 123.5 μM. For maximum reaction velocity (Vmax), the addition of BSA increased the Vmax of (R)-fenoprofen from 1.3 to 1.6 nmol/min/mg protein. In the contrast, BSA supplement decreased the Vmax value from 3.3 to 1.5 nmol/min/mg protein. Andrographolide-fenoprofen interaction was used as an example to investigate the influence of BSA supplement towards fenoprofen-relevant drug-drug interaction. The addition of 0.2% BSA in the incubation system significantly decreased the inhibition potential of andrographolide towards (R)-fenoprofen metabolism (P andrographolide towards the metabolism of (S)-fenoprofen. BSA supplement also changed the inhibition kinetic type and parameter of andrographolide towards the metabolism of (S)-fenoprofen. In conclusion, albumin supplement changes the metabolic behavior of fenoprofen enantiomers and the fenoprofen-andrographolide interaction. PMID:26037509

  18. How parental dietary behavior and food parenting practices affect children's dietary behavior: Interacting sources of influence?

    NARCIS (Netherlands)

    Larsen, J.K.; Hermans, R.C.J.; Sleddens, E.F.C.; Engels, R.C.M.E.; Fisher, J.O.; Kremers, S.P.J.

    2015-01-01

    Until now, the literatures on the effects of food parenting practices and parents' own dietary behavior on children's dietary behavior have largely been independent from one another. Integrating findings across these areas could provide insight on simultaneous and interacting influences on children'

  19. The interaction of early life experiences with COMT val158met affects anxiety sensitivity.

    Science.gov (United States)

    Baumann, C; Klauke, B; Weber, H; Domschke, K; Zwanzger, P; Pauli, P; Deckert, J; Reif, A

    2013-11-01

    The pathogenesis of anxiety disorders is considered to be multifactorial with a complex interaction of genetic factors and individual environmental factors. Therefore, the aim of this study was to examine gene-by-environment interactions of the genes coding for catechol-O-methyltransferase (COMT) and monoamine oxidase A (MAOA) with life events on measures related to anxiety. A sample of healthy subjects (N = 782; thereof 531 women; mean age M = 24.79, SD = 6.02) was genotyped for COMT rs4680 and MAOA-uVNTR (upstream variable number of tandem repeats), and was assessed for childhood adversities [Childhood Trauma Questionnaire (CTQ)], anxiety sensitivity [Anxiety Sensitivity Index (ASI)] and anxious apprehension [Penn State Worry Questionnaire (PSWQ)]. Main and interaction effects of genotype, environment and gender on measures related to anxiety were assessed by means of regression analyses. Association analysis showed no main gene effect on either questionnaire score. A significant interactive effect of childhood adversities and COMT genotype was observed: Homozygosity for the low-active met allele and high CTQ scores was associated with a significant increment of explained ASI variance [R(2) = 0.040, false discovery rate (FDR) corrected P = 0.04]. A borderline interactive effect with respect to MAOA-uVNTR was restricted to the male subgroup. Carriers of the low-active MAOA allele who reported more aversive experiences in childhood exhibited a trend for enhanced anxious apprehension (R(2) = 0.077, FDR corrected P = 0.10). Early aversive life experiences therefore might increase the vulnerability to anxiety disorders in the presence of homozygosity for the COMT 158met allele or low-active MAOA-uVNTR alleles.

  20. Silica-coated magnetic nanoparticles impair proteasome activity and increase the formation of cytoplasmic inclusion bodies in vitro.

    Science.gov (United States)

    Phukan, Geetika; Shin, Tae Hwan; Shim, Jeom Soon; Paik, Man Jeong; Lee, Jin-Kyu; Choi, Sangdun; Kim, Yong Man; Kang, Seong Ho; Kim, Hyung Sik; Kang, Yup; Lee, Soo Hwan; Mouradian, M Maral; Lee, Gwang

    2016-07-05

    The potential toxicity of nanoparticles, particularly to neurons, is a major concern. In this study, we assessed the cytotoxicity of silica-coated magnetic nanoparticles containing rhodamine B isothiocyanate dye (MNPs@SiO2(RITC)) in HEK293 cells, SH-SY5Y cells, and rat primary cortical and dopaminergic neurons. In cells treated with 1.0 μg/μl MNPs@SiO2(RITC), the expression of several genes related to the proteasome pathway was altered, and proteasome activity was significantly reduced, compared with control and with 0.1 μg/μl MNPs@SiO2(RITC)-treated cells. Due to the reduction of proteasome activity, formation of cytoplasmic inclusions increased significantly in HEK293 cells over-expressing the α-synuclein interacting protein synphilin-1 as well as in primary cortical and dopaminergic neurons. Primary neurons, particularly dopaminergic neurons, were more vulnerable to MNPs@SiO2(RITC) than SH-SY5Y cells. Cellular polyamines, which are associated with protein aggregation, were significantly altered in SH-SY5Y cells treated with MNPs@SiO2(RITC). These findings highlight the mechanisms of neurotoxicity incurred by nanoparticles.

  1. Characterization of a Proteasome and TAP-independent Presentation of Intracellular Epitopes by HLA-B27 Molecules

    KAUST Repository

    Magnacca, A.

    2012-07-17

    Nascent HLA-class I molecules are stabilized by proteasome-derived peptides in the ER and the new complexes proceed to the cell surface through the post-ER vesicles. It has been shown, however, that less stable complexes can exchange peptides in the Trans Golgi Network (TGN). HLA-B27 are the most studied HLA-class I molecules due to their association with Ankylosing Spondylitis (AS). Chimeric proteins driven by TAT of HIV have been exploited by us to deliver viral epitopes, whose cross-presentation by the HLA-B27 molecules was proteasome and TAP-independent and not restricted to Antigen-Presenting Cells (APC). Here, using these chimeric proteins as epitope suppliers, we compared with each other and with the HLA-A2 molecules, the two HLA-B*2705 and B*2709 alleles differing at residue 116 (D116H) and differentially associated with AS. We found that the antigen presentation by the two HLA-B27 molecules was proteasome-, TAP-, and APC-independent whereas the presentation by the HLA-A2 molecules required proteasome, TAP and professional APC. Assuming that such difference could be due to the unpaired, highly reactive Cys-67 distinguishing the HLA-B27 molecules, C67S mutants in HLA-B*2705 and B*2709 and V67C mutant in HLA-A*0201 were also analyzed. The results showed that this mutation did not influence the HLA-A2-restricted antigen presentation while it drastically affected the HLA-B27-restricted presentation with, however, remarkable differences between B*2705 and B*2709. The data, together with the occurrence on the cell surface of unfolded molecules in the case of C67S-B*2705 mutant but not in that of C67S-B*2709 mutant, indicates that Cys-67 has a more critical role in stabilizing the B*2705 rather than the B*2709 complexes.

  2. How 3D Interaction Metaphors Affect User Experience in Collaborative Virtual Environment

    Directory of Open Access Journals (Sweden)

    Hamid Hrimech

    2011-01-01

    Full Text Available In this paper we presents the results of our experimental study which aims to understand the impact of three interaction 3D metaphors (ray casting, GoGo, and virtual hand on the user experience in a semi-immersive collaborative virtual environment (the Braccetto System. For each session, participants are grouped in twos to reconstruct a puzzle by an assemblage of cubes. The puzzle to reconstruct corresponds to a gradient of colors. We found that there is a significant difference in the user experience by changing the interaction metaphor on the copresence, awareness, involvement, collaborative effort, satisfaction usability, and preference. These findings provide a basis for designing 3D navigation techniques in a CVE.

  3. How parental dietary behavior and food parenting practices affect children's dietary behavior. Interacting sources of influence?

    Science.gov (United States)

    Larsen, Junilla K; Hermans, Roel C J; Sleddens, Ester F C; Engels, Rutger C M E; Fisher, Jennifer O; Kremers, Stef P J

    2015-06-01

    Until now, the literatures on the effects of food parenting practices and parents' own dietary behavior on children's dietary behavior have largely been independent from one another. Integrating findings across these areas could provide insight on simultaneous and interacting influences on children's food intake. In this narrative review, we provide a conceptual model that bridges the gap between both literatures and consists of three main hypotheses. First, parental dietary behavior and food parenting practices are important interactive sources of influence on children's dietary behavior and Body Mass Index (BMI). Second, parental influences are importantly mediated by changes in the child's home food environment. Third, parenting context (i.e., parenting styles and differential parental treatment) moderates effects of food parenting practices, whereas child characteristics (i.e., temperament and appetitive traits) mainly moderate effects of the home food environment. Future studies testing (parts of) this conceptual model are needed to inform effective parent-child overweight preventive interventions.

  4. Factors affecting virus dynamics and microbial host-virus interactions in marine environments

    OpenAIRE

    K. D. A. Mojica; Brussaard, C.P.D.

    2014-01-01

    Marine microorganisms constitute the largest percentage of living biomass and serve as the major driving force behind nutrient and energy cycles. While viruses only comprise a small percentage of this biomass (i.e., 5%), they dominate in numerical abundance and genetic diversity. Through host infection and mortality, viruses affect microbial population dynamics, community composition, genetic evolution, and biogeochemical cycling. However, the field of marine viral ecology is currently limite...

  5. Sediment-water interaction in a water reservoir affected by acid mine drainage : experimental and modeling

    OpenAIRE

    Torres Sánchez, Ester

    2013-01-01

    The discharge of acid mine drainage into a water reservoir may seriously affect the water quality. In this setting, sediment is commonly thought to act as a sink for pollutants. However, redox oscillations in the bottom water promoted by stratification-turnover events may significantly alter the metal cycling. A new sequential extraction procedure has been developed to study the metal partitioning in the sediment. The new scheme for iron, sulfur and organic carbon rich sediments was evaluated...

  6. Motion and emotion: depression reduces psychomotor performance and alters affective movements in caregiving interactions

    OpenAIRE

    Young, Katherine S.; Parsons, Christine E.; Alan eStein; Kringelbach, Morten L.

    2015-01-01

    Background: Impaired social functioning is a well-established feature of depression. Evidence to date suggests that disrupted processing of emotional cues may constitute part of this impairment. Beyond processing of emotional cues, fluent social interactions require that people physically move in synchronized, contingent ways. Disruptions to physical movements are a diagnostic feature of depression (psychomotor disturbance) but have not previously been assessed in the context of social functi...

  7. Network Regulation and Support Schemes - How Policy Interactions Affect the Integration of Distributed Generation

    DEFF Research Database (Denmark)

    Ropenus, Stephanie; Jacobsen, Henrik; Schröder, Sascha Thorsten

    2011-01-01

    -off between the incentives for these two market agents to facilitate the integration of distributed generation. Secondly, the interaction of these policy dimensions is analyzed, including case studies based on five EU Member States. Aspects of operational nature and investments in grid and distributed...... generation facilities are covered. The question in which policy segment to incorporate locational signals is at the heart of the debate...

  8. Transgenerational interactions involving parental age and immune status affect female reproductive success in Drosophila melanogaster.

    Science.gov (United States)

    Nystrand, M; Dowling, D K

    2014-11-01

    It is well established that the parental phenotype can influence offspring phenotypic expression, independent of the effects of the offspring's own genotype. Nonetheless, the evolutionary implications of such parental effects remain unclear, partly because previous studies have generally overlooked the potential for interactions between parental sources of non-genetic variance to influence patterns of offspring phenotypic expression. We tested for such interactions, subjecting male and female Drosophila melanogaster of two different age classes to an immune activation challenge or a control treatment. Flies were then crossed in all age and immune status combinations, and the reproductive success of their immune- and control-treated daughters measured. We found that daughters produced by two younger parents exhibited reduced reproductive success relative to those of other parental age combinations. Furthermore, immune-challenged daughters exhibited higher reproductive success when produced by immune-challenged relative to control-treated mothers, a pattern consistent with transgenerational immune priming. Finally, a complex interplay between paternal age and parental immune statuses influenced daughter's reproductive success. These findings demonstrate the dynamic nature of age- and immune-mediated parental effects, traceable to both parents, and regulated by interactions between parents and between parents and offspring.

  9. Habitat traits and species interactions differentially affect abundance and body size in pond-breeding amphibians.

    Science.gov (United States)

    Ousterhout, Brittany H; Anderson, Thomas L; Drake, Dana L; Peterman, William E; Semlitsch, Raymond D

    2015-07-01

    In recent studies, habitat traits have emerged as stronger predictors of species occupancy, abundance, richness and diversity than competition. However, in many cases, it remains unclear whether habitat also mediates processes more subtle than competitive exclusion, such as growth, or whether intra- and interspecific interactions among individuals of different species may be better predictors of size. To test whether habitat traits are a stronger predictor of abundance and body size than intra- and interspecific interactions, we measured the density and body size of three species of larval salamanders in 192 ponds across a landscape. We found that the density of larvae was best predicted by models that included habitat features, while models incorporating interactions among individuals of different species best explained the body size of larvae. Additionally, we found a positive relationship between focal species density and congener density, while focal species body size was negatively related to congener density. We posit that salamander larvae may not experience competitive exclusion and thus reduced densities, but instead compensate for increased competition behaviourally (e.g. reduced foraging), resulting in decreased growth. The discrepancy between larval density and body size, a strong predictor of fitness in this system, also highlights a potential shortcoming in using density or abundance as a metric of habitat quality or population health. PMID:25643605

  10. Host protein Snapin interacts with human cytomegalovirus pUL130 and affects viral DNA replication

    Indian Academy of Sciences (India)

    Guili Wang; Gaowei Ren; Xin Cui; Yanpin Ma; Ying Qi; Yujing Huang; Zhongyang Liu; Zhengrong Sun; Qiang Ruan

    2016-06-01

    The interplay between the host and Human cytomegalovirus (HCMV) plays a pivotal role in the outcome of an infection. HCMV growth in endothelial and epithelial cells requires expression of viral proteins UL128, UL130, and UL131 proteins (UL128-131), of which UL130 is the largest gene and the only one that is not interrupted by introns. Mutation of the C terminus of the UL130 protein causes reduced tropism of endothelial cells (EC). However, very few host factors have been identified that interact with the UL130 protein. In this study, HCMV UL130 protein was shown to directly interact with the human protein Snapin in human embryonic kidney HEK293 cells by Yeast two-hybrid screening, in vitro glutathione S-transferase (GST) pull-down, and co-immunoprecipitation. Additionally, heterologous expression of protein UL130 revealed co-localization with Snapin in the cell membrane and cytoplasm of HEK293 cells using fluorescence confocal microscopy. Furthermore, decreasing the level of Snapin via specific small interfering RNAs decreased the number of viral DNA copies and titer in HCMV-infected U373-S cells. Taken together, these results suggest that Snapin, the pUL130 interacting protein, has a role in modulating HCMV DNA synthesis.

  11. Role of the Ubiquitin-Proteasome Systems in the Biology and Virulence of Protozoan Parasites

    Directory of Open Access Journals (Sweden)

    Christian Muñoz

    2015-01-01

    Full Text Available In eukaryotic cells, proteasomes perform crucial roles in many cellular pathways by degrading proteins to enforce quality control and regulate many cellular processes such as cell cycle progression, signal transduction, cell death, immune responses, metabolism, protein-quality control, and development. The catalytic heart of these complexes, the 20S proteasome, is highly conserved in bacteria, yeast, and humans. However, until a few years ago, the role of proteasomes in parasite biology was completely unknown. Here, we summarize findings about the role of proteasomes in protozoan parasites biology and virulence. Several reports have confirmed the role of proteasomes in parasite biological processes such as cell differentiation, cell cycle, proliferation, and encystation. Proliferation and cell differentiation are key steps in host colonization. Considering the importance of proteasomes in both processes in many different parasites such as Trypanosoma, Leishmania, Toxoplasma, and Entamoeba, parasite proteasomes might serve as virulence factors. Several pieces of evidence strongly suggest that the ubiquitin-proteasome pathway is also a viable parasitic therapeutic target. Research in recent years has shown that the proteasome is a valid drug target for sleeping sickness and malaria. Then, proteasomes are a key organelle in parasite biology and virulence and appear to be an attractive new chemotherapeutic target.

  12. Role of the Ubiquitin-Proteasome Systems in the Biology and Virulence of Protozoan Parasites.

    Science.gov (United States)

    Muñoz, Christian; San Francisco, Juan; Gutiérrez, Bessy; González, Jorge

    2015-01-01

    In eukaryotic cells, proteasomes perform crucial roles in many cellular pathways by degrading proteins to enforce quality control and regulate many cellular processes such as cell cycle progression, signal transduction, cell death, immune responses, metabolism, protein-quality control, and development. The catalytic heart of these complexes, the 20S proteasome, is highly conserved in bacteria, yeast, and humans. However, until a few years ago, the role of proteasomes in parasite biology was completely unknown. Here, we summarize findings about the role of proteasomes in protozoan parasites biology and virulence. Several reports have confirmed the role of proteasomes in parasite biological processes such as cell differentiation, cell cycle, proliferation, and encystation. Proliferation and cell differentiation are key steps in host colonization. Considering the importance of proteasomes in both processes in many different parasites such as Trypanosoma, Leishmania, Toxoplasma, and Entamoeba, parasite proteasomes might serve as virulence factors. Several pieces of evidence strongly suggest that the ubiquitin-proteasome pathway is also a viable parasitic therapeutic target. Research in recent years has shown that the proteasome is a valid drug target for sleeping sickness and malaria. Then, proteasomes are a key organelle in parasite biology and virulence and appear to be an attractive new chemotherapeutic target.

  13. Distinct specificities of Mycobacterium tuberculosis and mammalian proteasomes for N-acetyl tripeptide substrates.

    Science.gov (United States)

    Lin, Gang; Tsu, Christopher; Dick, Lawrence; Zhou, Xi K; Nathan, Carl

    2008-12-01

    The proteasome of Mycobacterium tuberculosis (Mtb) is a validated and drug-treatable target for therapeutics. To lay ground-work for developing peptide-based inhibitors with a useful degree of selectivity for the Mtb proteasome over those of the host, we used a library of 5,920 N-acetyl tripeptide-aminomethylcoumarins to contrast the substrate preferences of the recombinant Mtb proteasome wild type and open gate mutant, the Rhodococcus erythropolis proteasome, and the bovine proteasome with activator PA28. The Mtb proteasome was distinctive in strictly preferring P1 = tryptophan, particularly in combination with P3 = glycine, proline, lysine or arginine. Screening results were validated with Michalis-Menten kinetic analyses of 21 oligopeptide aminomethyl-coumarin substrates. Bortezomib, a proteasome inhibitor in clinical use, and 17 analogs varying only at P1 were used to examine the differential impact of inhibitors on human and Mtb proteasomes. The results with the inhibitor panel confirmed those with the substrate panel in demonstrating differential preferences of Mtb and mammalian proteasomes at the P1 amino acid. Changing P1 in bortezomib from Leu to m-CF(3)-Phe led to a 220-fold increase in IC(50) against the human proteasome, whereas changing a P1 Ala to m-F-Phe decreased the IC(50) 400-fold against the Mtb proteasome. The change of a P1 Ala to m-Cl-Phe led to an 8000-fold shift in inhibitory potency in favor of the Mtb proteasome, resulting in 8-fold selectivity. Combinations of preferred amino acids at different sites may thus improve the species selectivity of peptide-based inhibitors that target the Mtb proteasome. PMID:18829465

  14. Identification of nitric oxide as an endogenous inhibitor of 26S proteasomes in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Hongtao Liu

    Full Text Available The 26S proteasome plays a fundamental role in almost all eukaryotic cells, including vascular endothelial cells. However, it remains largely unknown how proteasome functionality is regulated in the vasculature. Endothelial nitric oxide (NO synthase (eNOS-derived NO is known to be essential to maintain endothelial homeostasis. The aim of the present study was to establish the connection between endothelial NO and 26S proteasome functionality in vascular endothelial cells. The 26S proteasome reporter protein levels, 26S proteasome activity, and the O-GlcNAcylation of Rpt2, a key subunit of the proteasome regulatory complex, were assayed in 26S proteasome reporter cells, human umbilical vein endothelial cells (HUVEC, and mouse aortic tissues isolated from 26S proteasome reporter and eNOS knockout mice. Like the other selective NO donors, NO derived from activated eNOS (by pharmacological and genetic approach increased O-GlcNAc modification of Rpt2, reduced proteasome chymotrypsin-like activity, and caused 26S proteasome reporter protein accumulation. Conversely, inactivation of eNOS reversed all the effects. SiRNA knockdown of O-GlcNAc transferase (OGT, the key enzyme that catalyzes protein O-GlcNAcylation, abolished NO-induced effects. Consistently, adenoviral overexpression of O-GlcNAcase (OGA, the enzyme catalyzing the removal of the O-GlcNAc group, mimicked the effects of OGT knockdown. Finally, compared to eNOS wild type aortic tissues, 26S proteasome reporter mice lacking eNOS exhibited elevated 26S proteasome functionality in parallel with decreased Rpt2 O-GlcNAcylation, without changing the levels of Rpt2 protein. In conclusion, the eNOS-derived NO functions as a physiological suppressor of the 26S proteasome in vascular endothelial cells.

  15. Phosphocreatine interacts with phospholipids, affects membrane properties and exerts membrane-protective effects.

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    Malgorzata Tokarska-Schlattner

    Full Text Available A broad spectrum of beneficial effects has been ascribed to creatine (Cr, phosphocreatine (PCr and their cyclic analogues cyclo-(cCr and phospho-cyclocreatine (PcCr. Cr is widely used as nutritional supplement in sports and increasingly also as adjuvant treatment for pathologies such as myopathies and a plethora of neurodegenerative diseases. Additionally, Cr and its cyclic analogues have been proposed for anti-cancer treatment. The mechanisms involved in these pleiotropic effects are still controversial and far from being understood. The reversible conversion of Cr and ATP into PCr and ADP by creatine kinase, generating highly diffusible PCr energy reserves, is certainly an important element. However, some protective effects of Cr and analogues cannot be satisfactorily explained solely by effects on the cellular energy state. Here we used mainly liposome model systems to provide evidence for interaction of PCr and PcCr with different zwitterionic phospholipids by applying four independent, complementary biochemical and biophysical assays: (i chemical binding assay, (ii surface plasmon resonance spectroscopy (SPR, (iii solid-state (31P-NMR, and (iv differential scanning calorimetry (DSC. SPR revealed low affinity PCr/phospholipid interaction that additionally induced changes in liposome shape as indicated by NMR and SPR. Additionally, DSC revealed evidence for membrane packing effects by PCr, as seen by altered lipid phase transition. Finally, PCr efficiently protected against membrane permeabilization in two different model systems: liposome-permeabilization by the membrane-active peptide melittin, and erythrocyte hemolysis by the oxidative drug doxorubicin, hypoosmotic stress or the mild detergent saponin. These findings suggest a new molecular basis for non-energy related functions of PCr and its cyclic analogue. PCr/phospholipid interaction and alteration of membrane structure may not only protect cellular membranes against various insults

  16. Double trouble. Trait food craving and impulsivity interactively predict food-cue affected behavioral inhibition.

    Science.gov (United States)

    Meule, Adrian; Kübler, Andrea

    2014-08-01

    Impulsivity and food craving have both been implicated in overeating. Recent results suggest that both processes may interactively predict increased food intake. In the present study, female participants performed a Go/No-go task with pictures of high- and low-calorie foods. They were instructed to press a button in response to the respective target category, but withhold responses to the other category. Target category was switched after every other block, thereby creating blocks in which stimulus-response mapping was the same as in the previous block (nonshift blocks) and blocks in which it was reversed (shift blocks). The Food Cravings Questionnaires and the Barratt Impulsiveness Scale were used to assess trait and state food craving and attentional, motor, and nonplanning impulsivity. Participants had slower reaction times and more omission errors (OE) in high-calorie than in low-calorie blocks. Number of commission errors (CE) and OE was higher in shift blocks than in nonshift blocks. Trait impulsivity was positively correlated with CE in shift blocks while trait food craving was positively correlated with CE in high-calorie blocks. Importantly, CE in high-calorie-shift blocks were predicted by an interaction of food craving × impulsivity such that the relationship between food craving and CE was particularly strong at high levels of impulsivity, but vanished at low levels of impulsivity. Thus, impulsive reactions to high-calorie food-cues are particularly pronounced when both trait impulsivity and food craving is high, but low levels of impulsivity can compensate for high levels of trait food craving. Results support models of self-regulation which assume that interactive effects of low top-down control and strong reward sensitive, bottom-up mechanisms may determine eating-related disinhibition, ultimately leading to increased food intake.

  17. Sea Breezes over the Red Sea: Affect of topography and interaction with Desert Convective Boundary Layer

    Science.gov (United States)

    Khan, Basit A.; Stenchikov, Georgiy; Abualnaja, Yasser

    2014-05-01

    Thermodynamic structure of sea-breeze, its interaction with coastal mountains, desert plateau and desert convective boundary layer have been investigated in the middle region of the Red Sea around 25°N, at the Western coast of Saudi Arabia. Sea and land breeze is a common meteorological phenomenon in most of the coastal regions around the world. Sea-Breeze effects the local meteorology and cause changes in wind speed, direction, cloud cover and sometimes precipitation. The occurrence of sea-breeze, its intensity and landward propagation are important for wind energy resource assessment, load forecasting for existing wind farms, air pollution, marine and aviation applications. The thermally induced mesoscale circulation of sea breeze modifies the desert Planetary Boundary Layer (PBL) by forming Convective Internal Boundary Layer (CIBL), and propagates inland as a density current. The leading edge of the denser marine air rapidly moves inland undercutting the hot and dry desert air mass. The warm air lifts up along the frontal boundary and if contains enough moisture a band of clouds is formed along the sea breeze front (SBF). This study focuses on the thermodynamic structure of sea-breeze as it propagates over coastal rocky mountain range of Al-Sarawat, east of the Red Sea coast, and the desert plateau across the mountain range. Additional effects of topographical gaps such as Tokar gap on the dynamics of sea-land breezes have also been discussed. Interaction of SBF with the desert convective boundary layer provide extra lifting that could further enhance the convective instability along the frontal boundary. This study provides a detailed analysis of the thermodynamics of interaction of the SBF and convective internal boundary layer over the desert. Observational data from a buoy and meteorological stations have been utilized while The Advanced Research WRF (ARW) modeling system has been employed in real and 2D idealized configuration.

  18. Protein-binding RNA aptamers affect molecular interactions distantly from their binding sites.

    Directory of Open Access Journals (Sweden)

    Daniel M Dupont

    Full Text Available Nucleic acid aptamer selection is a powerful strategy for the development of regulatory agents for molecular intervention. Accordingly, aptamers have proven their diligence in the intervention with serine protease activities, which play important roles in physiology and pathophysiology. Nonetheless, there are only a few studies on the molecular basis underlying aptamer-protease interactions and the associated mechanisms of inhibition. In the present study, we use site-directed mutagenesis to delineate the binding sites of two 2´-fluoropyrimidine RNA aptamers (upanap-12 and upanap-126 with therapeutic potential, both binding to the serine protease urokinase-type plasminogen activator (uPA. We determine the subsequent impact of aptamer binding on the well-established molecular interactions (plasmin, PAI-1, uPAR, and LRP-1A controlling uPA activities. One of the aptamers (upanap-126 binds to the area around the C-terminal α-helix in pro-uPA, while the other aptamer (upanap-12 binds to both the β-hairpin of the growth factor domain and the kringle domain of uPA. Based on the mapping studies, combined with data from small-angle X-ray scattering analysis, we construct a model for the upanap-12:pro-uPA complex. The results suggest and highlight that the size and shape of an aptamer as well as the domain organization of a multi-domain protein such as uPA, may provide the basis for extensive sterical interference with protein ligand interactions considered distant from the aptamer binding site.

  19. Intracellular sodium affects ouabain interaction with the Na/K pump in cultured chick cardiac myocytes

    OpenAIRE

    1990-01-01

    Whether a given dose of ouabain will produce inotropic or toxic effects depends on factors that affect the apparent affinity (K0.5) of the Na/K pump for ouabain. To accurately resolve these factors, especially the effect of intracellular Na concentration (Nai), we have applied three complementary techniques for measuring the K0.5 for ouabain in cultured embryonic chick cardiac myocytes. Under control conditions with 5.4 mM Ko, the value of the K0.5 for ouabain was 20.6 +/- 1.2, 12.3 +/- 1.7, ...

  20. Role of the Ubiquitin Proteasome System in Regulating Skin Pigmentation

    Directory of Open Access Journals (Sweden)

    Hideya Ando

    2009-10-01

    Full Text Available Pigmentation of the skin, hair and eyes is regulated by tyrosinase, the critical rate-limiting enzyme in melanin synthesis by melanocytes. Tyrosinase is degraded endogenously, at least in part, by the ubiquitin proteasome system (UPS. Several types of inherited hypopigmentary diseases, such as oculocutaneous albinism and Hermansky-Pudlak syndrome, involve the aberrant processing and/or trafficking of tyrosinase and its subsequent degradation which can occur due to the quality-control machinery. Studies on carbohydrate modifications have revealed that tyrosinase in the endoplasmic reticulum (ER is proteolyzed via ER-associated protein degradation and that tyrosinase degradation can also occur following its complete maturation in the Golgi. Among intrinsic factors that regulate the UPS, fatty acids have been shown to modulate tyrosinase degradation in contrasting manners through increased or decreased amounts of ubiquitinated tyrosinase that leads to its accelerated or decelerated degradation by proteasomes.

  1. The Role of Ubiquitine Proteasome Pathway in Carcinogenesis

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    N.Ceren Sumer Turanligil

    2010-02-01

    Full Text Available Ubiquitin works as a marker protein which targets misfolded or injured proteins to cellular degradation. It brings the abnormal proteins to a subcellular organelle named proteasome and it maintains the degradation of proteins in limited lenghts of peptides by leaving the process withuout being changed. Mistakes in ubiquitin-dependent proteolysis in various steps of carcinogenesis is known. In this review, we dealed with the effects of ubiquitin-proteasome pathway (UPP on carcinogenesis via intercellular signaling molecules like Ras, transcription factors like NF-kB, cytokines like TNF-alfa Tumor necrosis factor, protooncogenes like p53 and MDM2(murine double minute 2, components of cell cycle and DNA repair proteins like BRCA1. We also focused on the relationship of UPP on antigen presentation which is active in immune response and its place in the aetiology of colon cancer to provide a specific example. [Archives Medical Review Journal 2010; 19(1.000: 36-55

  2. Divalent Ion Parameterization Strongly Affects Conformation and Interactions of an Anionic Biomimetic Polymer

    Energy Technology Data Exchange (ETDEWEB)

    Daily, Michael D.; Baer, Marcel D.; Mundy, Christopher J.

    2016-03-10

    The description of peptides and the use of molecular dynamics simulations to refine structures and investigate the dynamics on an atomistic scale are well developed. Through a consensus in this community over multiple decades, parameters were developed for molecular interactions that only require the sequence of amino-acids and an initial guess for the three-dimensional structure. The recent discovery of peptoids will require a retooling of the currently available interaction potentials in order to have the same level of confidence in the predicted structures and pathways as there is presently in the peptide counterparts. Here we present modeling of peptoids using a combination of ab initio molecular dynamics (AIMD) and atomistic resolution classical forcefield (FF) to span the relevant time and length scales. To properly account for the dominant forces that stabilize ordered structures of peptoids, namely steric-, electrostatic, and hydrophobic interactions mediated through sidechain-sidechain interactions in the FF model, those have to be first mapped out using high fidelity atomistic representations. A key feature here is not only to use gas phase quantum chemistry tools, but also account for solvation effects in the condensed phase through AIMD. One major challenge is to elucidate ion binding to charged or polar regions of the peptoid and its concomitant role in the creation of local order. Here, similar to proteins, a specific ion effect is observed suggesting that both the net charge and the precise chemical nature of the ion will need to be described. MDD was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative at Pacific Northwest National Laboratory. Research was funded by the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MDB acknowledges support from US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Material & Engineering. CJM acknowledges

  3. Inhibition of polyamine oxidase activity affects tumor development during the maize-Ustilago maydis interaction.

    Science.gov (United States)

    Jasso-Robles, Francisco Ignacio; Jiménez-Bremont, Juan Francisco; Becerra-Flora, Alicia; Juárez-Montiel, Margarita; Gonzalez, María Elisa; Pieckenstain, Fernando Luis; García de la Cruz, Ramón Fernando; Rodríguez-Kessler, Margarita

    2016-05-01

    Ustilago maydis is a biotrophic plant pathogenic fungus that leads to tumor development in the aerial tissues of its host, Zea mays. These tumors are the result of cell hypertrophy and hyperplasia, and are accompanied by the reprograming of primary and secondary metabolism of infected plants. Up to now, little is known regarding key plant actors and their role in tumor development during the interaction with U. maydis. Polyamines are small aliphatic amines that regulate plant growth, development and stress responses. In a previous study, we found substantial increases of polyamine levels in tumors. In the present work, we describe the maize polyamine oxidase (PAO) gene family, its contribution to hydrogen peroxide (H2O2) production and its possible role in tumor development induced by U. maydis. Histochemical analysis revealed that chlorotic lesions and maize tumors induced by U. maydis accumulate H2O2 to significant levels. Maize plants inoculated with U. maydis and treated with the PAO inhibitor 1,8-diaminooctane exhibit a notable reduction of H2O2 accumulation in infected tissues and a significant drop in PAO activity. This treatment also reduced disease symptoms in infected plants. Finally, among six maize PAO genes only the ZmPAO1, which encodes an extracellular enzyme, is up-regulated in tumors. Our data suggest that H2O2 produced through PA catabolism by ZmPAO1 plays an important role in tumor development during the maize-U. maydis interaction.

  4. Food availability affects the strength of mutualistic host-microbiota interactions in Daphnia magna.

    Science.gov (United States)

    Callens, Martijn; Macke, Emilie; Muylaert, Koenraad; Bossier, Peter; Lievens, Bart; Waud, Michael; Decaestecker, Ellen

    2016-04-01

    The symbiotic gut microbial community is generally known to have a strong impact on the fitness of its host. Nevertheless, it is less clear how the impact of symbiotic interactions on the hosts' fitness varies according to environmental circumstances such as changes in the diet. This study aims to get a better understanding of host-microbiota interactions under different levels of food availability. We conducted experiments with the invertebrate, experimental model organism Daphnia magna and compared growth, survival and reproduction of conventionalized symbiotic Daphnia with germ-free individuals given varying quantities of food. Our experiments revealed that the relative importance of the microbiota for the hosts' fitness varied according to dietary conditions. The presence of the microbiota had strong positive effects on Daphnia when food was sufficient or abundant, but had weaker effects under food limitation. Our results indicate that the microbiota can be a potentially important factor in determining host responses to changes in dietary conditions. Characterization of the host-associated microbiota further showed that Aeromonas sp. was the most prevalent taxon in the digestive tract of Daphnia.

  5. Radiative and Physiological Effects of Increased CO2: How Does This Interaction Affect Climate?

    Science.gov (United States)

    Bounoua, Lahouari

    2011-01-01

    Several climate models indicate that in a 2xCO2 environment, temperature and precipitation would increase and runoff would increase faster than precipitation. These models, however, did not allow the vegetation to increase its leaf density as a response to the physiological effects of increased CO2 and consequent changes in climate. Other assessments included these interactions but did not account for the vegetation downregulation to reduce plant's photosynthetic activity and as such resulted in a weak vegetation negative response. When we combine these interactions in climate simulations with 2xCO2, the associated increase in precipitation contributes primarily to increase evapotranspiration rather than surface runoff, consistent with observations, and results in an additional cooling effect not fully accounted for in previous 2xCO2 simulations. By accelerating the water cycle, this feedback slows but does not alleviate the projected warming, reducing the land surface warming by 0.6 C. Compared to previous studies, these results imply that long term negative feedback from CO2-induced increases in vegetation density could reduce temperature following a stabilization of CO2 concentration.

  6. Quantitative phosphoproteomics of proteasome inhibition in multiple myeloma cells.

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    Feng Ge

    Full Text Available BACKGROUND: The proteasome inhibitor bortezomib represents an important advance in the treatment of multiple myeloma (MM. Bortezomib inhibits the activity of the 26S proteasome and induces cell death in a variety of tumor cells; however, the mechanism of cytotoxicity is not well understood. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the differential phosphoproteome upon proteasome inhibition by using stable isotope labeling by amino acids in cell culture (SILAC in combination with phosphoprotein enrichment and LC-MS/MS analysis. In total 233 phosphoproteins were identified and 72 phosphoproteins showed a 1.5-fold or greater change upon bortezomib treatment. The phosphoproteins with expression alterations encompass all major protein classes, including a large number of nucleic acid binding proteins. Site-specific phosphopeptide quantitation revealed that Ser38 phosphorylation on stathmin increased upon bortezomib treatment, suggesting new mechanisms associated to bortezomib-induced apoptosis in MM cells. Further studies demonstrated that stathmin phosphorylation profile was modified in response to bortezomib treatment and the regulation of stathmin by phosphorylation at specific Ser/Thr residues participated in the cellular response induced by bortezomib. CONCLUSIONS/SIGNIFICANCE: Our systematic profiling of phosphorylation changes in response to bortezomib treatment not only advanced the global mechanistic understanding of the action of bortezomib on myeloma cells but also identified previously uncharacterized signaling proteins in myeloma cells.

  7. Network-oriented modeling addressing complexity of cognitive, affective and social interactions

    CERN Document Server

    Treur, Jan

    2016-01-01

    This book presents a new approach that can be applied to complex, integrated individual and social human processes. It provides an alternative means of addressing complexity, better suited for its purpose than and effectively complementing traditional strategies involving isolation and separation assumptions. Network-oriented modeling allows high-level cognitive, affective and social models in the form of (cyclic) graphs to be constructed, which can be automatically transformed into executable simulation models. The modeling format used makes it easy to take into account theories and findings about complex cognitive and social processes, which often involve dynamics based on interrelating cycles. Accordingly, it makes it possible to address complex phenomena such as the integration of emotions within cognitive processes of all kinds, of internal simulations of the mental processes of others, and of social phenomena such as shared understandings and collective actions. A variety of sample models – including ...

  8. Pain and affective memory biases interact to predict depressive symptoms in multiple sclerosis.

    Science.gov (United States)

    Bruce, J M; Polen, D; Arnett, P A

    2007-01-01

    A large literature supports a direct relationship between pain and depressive symptoms among various patient populations. Patients with multiple sclerosis (MS) frequently experience both pain and depression. Despite this, no relationship between pain and depression has been found in MS. The present investigation explored the relationship between pain and depression in a sample of patients with MS. Consistent with cognitive theories of depression, results supported the hypothesis that pain would only contribute to depression when MS patients exhibited a concomitant cognitive vulnerability. Cognitive vulnerability to depression was measured using a performance based affective memory bias (AMB) task. Patients with high levels of pain and negative AMB reported more depressive symptoms compared to patients with pain and positive AMB. Implications for the identification and treatment of depression in MS are discussed. PMID:17294612

  9. Interactions between major chlorogenic acid isomers and chemical changes in coffee brew that affect antioxidant activities.

    Science.gov (United States)

    Liang, Ningjian; Xue, Wei; Kennepohl, Pierre; Kitts, David D

    2016-12-15

    Coffee bean source and roasting conditions significantly (p<0.05) affected the content of chlorogenic acid (CGA) isomers, several indices of browning and subsequent antioxidant values. Principal component analysis was used to interpret the correlations between physiochemical and antioxidant parameters of coffee. CGA isomer content was positively correlated (p<0.001) to capacity of coffee to reduce nitric oxide and scavenge Frémy's salt. Indices of browning in roasted coffee were positively correlated (p<0.001) to ABTS and TEMPO radical scavenging capacity, respectively. Only the CGA content of coffee corresponded to intracellular antioxidant capacity measured in Caco-2 intestinal cells. This study concluded that the intracellular antioxidant capacity that best describes potential health benefits of coffee positively corresponds best with CGA content. PMID:27451179

  10. Short-Time Critical Behavior Affected by Weakly Long-Range Interactions

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuan; GUO Shuo-Hong; LI Zhi-Bing

    2001-01-01

    The theoretic renormalization group approach is applied to the study of short-time critical behavior of the Ginzburg-Landau model with weakly long-range interactions pσsps-p. The system initially at a high temperature is firstly quenched to the critical temperature Tc and then released to an evolution with a model A dynamics. A double expansion in ∈ = 2σ-d and α = 1 -σ/2 with α of order ∈ is employed, where d is the spatial dimension. The asymptotic scaling laws and the initial slip exponents θ' and θ for the order parameter and the response function respectively are calculated to the second order in ∈ for σ close to 2.

  11. Biofilm history and oxygen availability interact to affect habitat selection in a marine invertebrate.

    Science.gov (United States)

    Lagos, Marcelo E; White, Craig R; Marshall, Dustin J

    2016-07-01

    In marine systems, oxygen availability varies at small temporal and spatial scales, such that current oxygen levels may not reflect conditions of the past. Different studies have shown that marine invertebrate larvae can select settlement sites based on local oxygen levels and oxygenation history of the biofilm, but no study has examined the interaction of both. The influence of normoxic and hypoxic water and oxygenation history of biofilms on pre-settlement behavior and settlement of the bryozoan Bugula neritina was tested. Larvae used cues in a hierarchical way: the oxygen levels in the water prime larvae to respond, the response to different biofilms is contingent on oxygen levels in the water. When oxygen levels varied throughout biofilm formation, larvae responded differently depending on the history of the biofilm. It appears that B. neritina larvae integrate cues about current and historical oxygen levels to select the appropriate microhabitat and maximize their fitness. PMID:27169475

  12. Protein-binding RNA aptamers affect molecular interactions distantly from their binding sites

    DEFF Research Database (Denmark)

    Dupont, Daniel M; Thuesen, Cathrine K; Bøtkjær, Kenneth A;

    2015-01-01

    Nucleic acid aptamer selection is a powerful strategy for the development of regulatory agents for molecular intervention. Accordingly, aptamers have proven their diligence in the intervention with serine protease activities, which play important roles in physiology and pathophysiology. Nonetheless...... potential, both binding to the serine protease urokinase-type plasminogen activator (uPA). We determine the subsequent impact of aptamer binding on the well-established molecular interactions (plasmin, PAI-1, uPAR, and LRP-1A) controlling uPA activities. One of the aptamers (upanap-126) binds to the area...... around the C-terminal α-helix in pro-uPA, while the other aptamer (upanap-12) binds to both the β-hairpin of the growth factor domain and the kringle domain of uPA. Based on the mapping studies, combined with data from small-angle X-ray scattering analysis, we construct a model for the upanap-12:pro...

  13. Variable gene dispersal conditions and spatial deforestation patterns can interact to affect tropical tree conservation outcomes.

    Directory of Open Access Journals (Sweden)

    Yamini Kashimshetty

    Full Text Available Tropical lowland rain forest (TLRF biodiversity is under threat from anthropogenic factors including deforestation which creates forest fragments of different sizes that can further undergo various internal patterns of logging. Such interventions can modify previous equilibrium abundance and spatial distribution patterns of offspring recruitment and/or pollen dispersal. Little is known about how these aspects of deforestation and fragmentation might synergistically affect TLRF tree recovery demographics and population genetics in newly formed forest fragments. To investigate these TLRF anthropogenic disturbance processes we used the computer program NEWGARDEN (NG, which models spatially-explicit, individual-based plant populations, to simulate 10% deforestation in six different spatial logging patterns for the plant functional type of a long-lived TLRF canopy tree species. Further, each logging pattern was analyzed under nine varying patterns of offspring versus pollen dispersal distances that could have arisen post-fragmentation. Results indicated that gene dispersal condition (especially via offspring had a greater effect on population growth and genetic diversity retention (explaining 98.5% and 88.8% of the variance respectively than spatial logging pattern (0.2% and 4.7% respectively, with 'Near' distance dispersal maximizing population growth and genetic diversity relative to distant dispersal. Within logged regions of the fragment, deforestation patterns closer to fragment borders more often exhibited lower population recovery rates and founding genetic diversity retention relative to more centrally located logging. These results suggest newly isolated fragments have populations that are more sensitive to the way in which their offspring and pollen dispersers are affected than the spatial pattern in which subsequent logging occurs, and that large variation in the recovery rates of different TLRF tree species attributable to altered gene

  14. Mode of heparin attachment to nanocrystalline hydroxyapatite affects its interaction with bone morphogenetic protein-2.

    Science.gov (United States)

    Goonasekera, Chandhi S; Jack, Kevin S; Bhakta, Gajadhar; Rai, Bina; Luong-Van, Emma; Nurcombe, Victor; Cool, Simon M; Cooper-White, Justin J; Grøndahl, Lisbeth

    2015-12-16

    Heparin has a high affinity for bone morphogenetic protein-2 (BMP-2), which is a key growth factor in bone regeneration. The aim of this study was to investigate how the rate of release of BMP-2 was affected when adsorbed to nanosized hydroxyapatite (HAP) particles functionalized with heparin by different methods. Heparin was attached to the surface of HAP, either via adsorption or covalent coupling, via a 3-aminopropyltriethoxysilane (APTES) layer. The chemical composition of the particles was evaluated using X-ray photoelectron spectroscopy and elemental microanalysis, revealing that the heparin grafting densities achieved were dependent on the curing temperature used in the fabrication of APTES-modified HAP. Comparable amounts of heparin were attached via both covalent coupling and adsorption to the APTES-modified particles, but characterization of the particle surfaces by zeta potential and Brunauer-Emmett-Teller measurements indicated that the conformation of the heparin on the surface was dependent on the method of attachment, which in turn affected the stability of heparin on the surface. The release of BMP-2 from the particles after 7 days in phosphate-buffered saline found that 31% of the loaded BMP-2 was released from the APTES-modified particles with heparin covalently attached, compared to 16% from the APTES-modified particles with the heparin adsorbed. Moreover, when heparin was adsorbed onto pure HAP, it was found that the BMP-2 released after 7 days was 5% (similar to that from unmodified HAP). This illustrates that by altering the mode of attachment of heparin to HAP the release profile and total release of BMP-2 can be manipulated. Importantly, the BMP-2 released from all the heparin particle types was found by the SMAD 1/5/8 phosphorylation assay to be biologically active.

  15. Muecas: a multi-sensor robotic head for affective human robot interaction and imitation.

    Science.gov (United States)

    Cid, Felipe; Moreno, Jose; Bustos, Pablo; Núñez, Pedro

    2014-04-28

    This paper presents a multi-sensor humanoid robotic head for human robot interaction. The design of the robotic head, Muecas, is based on ongoing research on the mechanisms of perception and imitation of human expressions and emotions. These mechanisms allow direct interaction between the robot and its human companion through the different natural language modalities: speech, body language and facial expressions. The robotic head has 12 degrees of freedom, in a human-like configuration, including eyes, eyebrows, mouth and neck, and has been designed and built entirely by IADeX (Engineering, Automation and Design of Extremadura) and RoboLab. A detailed description of its kinematics is provided along with the design of the most complex controllers. Muecas can be directly controlled by FACS (Facial Action Coding System), the de facto standard for facial expression recognition and synthesis. This feature facilitates its use by third party platforms and encourages the development of imitation and of goal-based systems. Imitation systems learn from the user, while goal-based ones use planning techniques to drive the user towards a final desired state. To show the flexibility and reliability of the robotic head, the paper presents a software architecture that is able to detect, recognize, classify and generate facial expressions in real time using FACS. This system has been implemented using the robotics framework, RoboComp, which provides hardware-independent access to the sensors in the head. Finally, the paper presents experimental results showing the real-time functioning of the whole system, including recognition and imitation of human facial expressions.

  16. MVP-Associated Filamin A Mutations Affect FlnA-PTPN12 (PTP-PEST Interactions

    Directory of Open Access Journals (Sweden)

    Damien Duval

    2015-09-01

    Full Text Available Although the genetic basis of mitral valve prolapse (MVP has now been clearly established, the molecular and cellular mechanisms involved in the pathological processes associated to a specific mutation often remain to be determined. The FLNA gene (encoding Filamin A; FlnA was the first gene associated to non-syndromic X-linked myxomatous valvular dystrophy, but the impacts of the mutations on its function remain un-elucidated. Here, using the first repeats (1–8 of FlnA as a bait in a yeast two-hybrid screen, we identified the tyrosine phosphatase PTPN12 (PTP-PEST as a specific binding partner of this region of FlnA protein. In addition, using yeast two-hybrid trap assay pull down and co-immunoprecipitation experiments, we showed that the MVP-associated FlnA mutations (G288R, P637Q, H743P abolished FlnA/PTPN12 interactions. PTPN12 is a key regulator of signaling pathways involved in cell-extracellular matrix (ECM crosstalk, cellular responses to mechanical stress that involve integrins, focal adhesion transduction pathways, and actin cytoskeleton dynamics. Interestingly, we showed that the FlnA mutations impair the activation status of two PTPN12 substrates, the focal adhesion associated kinase Src, and the RhoA specific activating protein p190RhoGAP. Together, these data point to PTPN12/FlnA interaction and its weakening by FlnA mutations as a mechanism potentially involved in the physiopathology of FlnA-associated MVP.

  17. Disruption of NAD~+ binding site in glyceraldehyde 3-phosphate dehydrogenase affects its intranuclear interactions

    Institute of Scientific and Technical Information of China (English)

    Manali; Phadke; Natalia; Krynetskaia; Anurag; Mishra; Carlos; Barrero; Salim; Merali; Scott; A; Gothe; Evgeny; Krynetskiy

    2015-01-01

    AIM:To characterize phosphorylation of human glyceraldehyde 3-phosphate dehydrogenase(GAPDH),and mobility of GAPDH in cancer cells treated with chemotherapeutic agents. METHODS:We used proteomics analysis to detect and characterize phosphorylation sites within human GAPDH. Site-specific mutagenesis and alanine scanning was then performed to evaluate functional significance of phosphorylation sites in the GAPDH polypeptide chain. Enzymatic properties of mutated GAPDH variants were assessed using kinetic studies. Intranuclear dynamics parameters(diffusion coefficient and the immobile fraction) were estimated using fluorescence recovery after photobleaching(FRAP) experiments and confocal microscopy. Molecular modeling experiments were performed to estimate the effects of mutations on NAD+ cofactor binding.RESULTS:Using MALDI-TOF analysis,we identified novel phosphorylation sites within the NAD+ binding center of GAPDH at Y94,S98,and T99. Using polyclonal antibody specific to phospho-T99-containing peptide within GAPDH,we demonstrated accumulation of phospho-T99-GAPDH inthe nuclear fractions of A549,HCT116,and SW48 cancer cel s after cytotoxic stress. We performed site-mutagenesis,and estimated enzymatic properties,intranuclear distribution,and intranuclear mobility of GAPDH mutated variants. Site-mutagenesis at positions S98 and T99 in the NAD+ binding center reduced enzymatic activity of GAPDH due to decreased affinity to NAD+(Km = 741 ± 257 μmol/L in T99 I vs 57 ± 11.1 μmol/L in wild type GAPDH. Molecular modeling experiments revealed the effect of mutations on NAD+ binding with GAPDH. FRAP(fluorescence recovery after photo bleaching) analysis showed that mutations in NAD+ binding center of GAPDH abrogated its intranuclear interactions. CONCLUSION:Our results suggest an important functional role of phosphorylated amino acids in the NAD+ binding center in GAPDH interactions with its intranuclear partners.

  18. How social interactions affect emotional memory accuracy: Evidence from collaborative retrieval and social contagion paradigms.

    Science.gov (United States)

    Kensinger, Elizabeth A; Choi, Hae-Yoon; Murray, Brendan D; Rajaram, Suparna

    2016-07-01

    In daily life, emotional events are often discussed with others. The influence of these social interactions on the veracity of emotional memories has rarely been investigated. The authors (Choi, Kensinger, & Rajaram Memory and Cognition, 41, 403-415, 2013) previously demonstrated that when the categorical relatedness of information is controlled, emotional items are more accurately remembered than neutral items. The present study examined whether emotion would continue to improve the accuracy of memory when individuals discussed the emotional and neutral events with others. Two different paradigms involving social influences were used to investigate this question and compare evidence. In both paradigms, participants studied stimuli that were grouped into conceptual categories of positive (e.g., celebration), negative (e.g., funeral), or neutral (e.g., astronomy) valence. After a 48-hour delay, recognition memory was tested for studied items and categorically related lures. In the first paradigm, recognition accuracy was compared when memory was tested individually or in a collaborative triad. In the second paradigm, recognition accuracy was compared when a prior retrieval session had occurred individually or with a confederate who supplied categorically related lures. In both of these paradigms, emotional stimuli were remembered more accurately than were neutral stimuli, and this pattern was preserved when social interaction occurred. In fact, in the first paradigm, there was a trend for collaboration to increase the beneficial effect of emotion on memory accuracy, and in the second paradigm, emotional lures were significantly less susceptible to the "social contagion" effect. Together, these results demonstrate that emotional memories can be more accurate than nonemotional ones even when events are discussed with others (Experiment 1) and even when that discussion introduces misinformation (Experiment 2). PMID:26907480

  19. Muecas: a multi-sensor robotic head for affective human robot interaction and imitation.

    Science.gov (United States)

    Cid, Felipe; Moreno, Jose; Bustos, Pablo; Núñez, Pedro

    2014-01-01

    This paper presents a multi-sensor humanoid robotic head for human robot interaction. The design of the robotic head, Muecas, is based on ongoing research on the mechanisms of perception and imitation of human expressions and emotions. These mechanisms allow direct interaction between the robot and its human companion through the different natural language modalities: speech, body language and facial expressions. The robotic head has 12 degrees of freedom, in a human-like configuration, including eyes, eyebrows, mouth and neck, and has been designed and built entirely by IADeX (Engineering, Automation and Design of Extremadura) and RoboLab. A detailed description of its kinematics is provided along with the design of the most complex controllers. Muecas can be directly controlled by FACS (Facial Action Coding System), the de facto standard for facial expression recognition and synthesis. This feature facilitates its use by third party platforms and encourages the development of imitation and of goal-based systems. Imitation systems learn from the user, while goal-based ones use planning techniques to drive the user towards a final desired state. To show the flexibility and reliability of the robotic head, the paper presents a software architecture that is able to detect, recognize, classify and generate facial expressions in real time using FACS. This system has been implemented using the robotics framework, RoboComp, which provides hardware-independent access to the sensors in the head. Finally, the paper presents experimental results showing the real-time functioning of the whole system, including recognition and imitation of human facial expressions. PMID:24787636

  20. Muecas: A Multi-Sensor Robotic Head for Affective Human Robot Interaction and Imitation

    Directory of Open Access Journals (Sweden)

    Felipe Cid

    2014-04-01

    Full Text Available This paper presents a multi-sensor humanoid robotic head for human robot interaction. The design of the robotic head, Muecas, is based on ongoing research on the mechanisms of perception and imitation of human expressions and emotions. These mechanisms allow direct interaction between the robot and its human companion through the different natural language modalities: speech, body language and facial expressions. The robotic head has 12 degrees of freedom, in a human-like configuration, including eyes, eyebrows, mouth and neck, and has been designed and built entirely by IADeX (Engineering, Automation and Design of Extremadura and RoboLab. A detailed description of its kinematics is provided along with the design of the most complex controllers. Muecas can be directly controlled by FACS (Facial Action Coding System, the de facto standard for facial expression recognition and synthesis. This feature facilitates its use by third party platforms and encourages the development of imitation and of goal-based systems. Imitation systems learn from the user, while goal-based ones use planning techniques to drive the user towards a final desired state. To show the flexibility and reliability of the robotic head, the paper presents a software architecture that is able to detect, recognize, classify and generate facial expressions in real time using FACS. This system has been implemented using the robotics framework, RoboComp, which provides hardware-independent access to the sensors in the head. Finally, the paper presents experimental results showing the real-time functioning of the whole system, including recognition and imitation of human facial expressions.

  1. The 26S Proteasome Degrades the Soluble but Not the Fibrillar Form of the Yeast Prion Ure2p In Vitro.

    Directory of Open Access Journals (Sweden)

    Kai Wang

    Full Text Available Yeast prions are self-perpetuating protein aggregates that cause heritable and transmissible phenotypic traits. Among these, [PSI+] and [URE3] stand out as the most studied yeast prions, and result from the self-assembly of the translation terminator Sup35p and the nitrogen catabolism regulator Ure2p, respectively, into insoluble fibrillar aggregates. Protein quality control systems are well known to govern the formation, propagation and transmission of these prions. However, little is known about the implication of the cellular proteolytic machineries in their turnover. We previously showed that the 26S proteasome degrades both the soluble and fibrillar forms of Sup35p and affects [PSI+] propagation. Here, we show that soluble native Ure2p is degraded by the proteasome in an ubiquitin-independent manner. Proteasomal degradation of Ure2p yields amyloidogenic N-terminal peptides and a C-terminal resistant fragment. In contrast to Sup35p, fibrillar Ure2p resists proteasomal degradation. Thus, structural variability within prions may dictate their ability to be degraded by the cellular proteolytic systems.

  2. Myxoma virus attenuates expression of activating transcription factor 4 (ATF4 which has implications for the treatment of proteasome inhibitor–resistant multiple myeloma

    Directory of Open Access Journals (Sweden)

    Dunlap KM

    2015-01-01

    Full Text Available Katherine M Dunlap, Mee Y Bartee, Eric Bartee Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA Abstract: The recent development of chemotherapeutic proteasome inhibitors, such as bortezomib, has improved the outcomes of patients suffering from the plasma cell malignancy multiple myeloma. Unfortunately, many patients treated with these drugs still suffer relapsing disease due to treatment-induced upregulation of the antiapoptotic protein Mcl1. We have recently demonstrated that an oncolytic poxvirus, known as myxoma, can rapidly eliminate primary myeloma cells by inducing cellular apoptosis. The efficacy of myxoma treatment on proteasome inhibitor–relapsed or –refractory myeloma, however, remains unknown. We now demonstrate that myxoma-based elimination of myeloma is not affected by cellular resistance to proteasome inhibitors. Additionally, myxoma virus infection specifically prevents expression of Mcl1 following induction of the unfolded protein response, by blocking translation of the unfolded protein response activating transcription factor (ATF4. These results suggest that myxoma-based oncolytic therapy represents an attractive option for myeloma patients whose disease is refractory to chemotherapeutic proteasome inhibitors due to upregulation of Mcl1. Keywords: drug resistance, oncolytic

  3. Computational Approaches for the Discovery of Human Proteasome Inhibitors: An Overview.

    Science.gov (United States)

    Guedes, Romina A; Serra, Patrícia; Salvador, Jorge A R; Guedes, Rita C

    2016-01-01

    Proteasome emerged as an important target in recent pharmacological research due to its pivotal role in degrading proteins in the cytoplasm and nucleus of eukaryotic cells, regulating a wide variety of cellular pathways, including cell growth and proliferation, apoptosis, DNA repair, transcription, immune response, and signaling processes. The last two decades witnessed intensive efforts to discover 20S proteasome inhibitors with significant chemical diversity and efficacy. To date, the US FDA approved to market three proteasome inhibitors: bortezomib, carfilzomib, and ixazomib. However new, safer and more efficient drugs are still required. Computer-aided drug discovery has long being used in drug discovery campaigns targeting the human proteasome. The aim of this review is to illustrate selected in silico methods like homology modeling, molecular docking, pharmacophore modeling, virtual screening, and combined methods that have been used in proteasome inhibitors discovery. Applications of these methods to proteasome inhibitors discovery will also be presented and discussed to raise improvements in this particular field. PMID:27438821

  4. 1.15 Å resolution structure of the proteasome-assembly chaperone Nas2 PDZ domain

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Chingakham R. [Kansas State University, 338 Ackert Hall, Manhattan, KS 66506 (United States); Lovell, Scott; Mehzabeen, Nurjahan [University of Kansas, Del Shankel Structural Biology Center, Lawrence, KS 66047 (United States); Chowdhury, Wasimul Q.; Geanes, Eric S. [Kansas State University, 338 Ackert Hall, Manhattan, KS 66506 (United States); Battaile, Kevin P. [IMCA-CAT Hauptman–Woodward Medical Research Institute, 9700 South Cass Avenue, Building 435A, Argonne, IL 60439 (United States); Roelofs, Jeroen, E-mail: jroelofs@ksu.edu [Kansas State University, 338 Ackert Hall, Manhattan, KS 66506 (United States)

    2014-03-25

    The proteasome-assembly chaperone Nas2 binds to the proteasome subunit Rpt5 using its PDZ domain. The structure of the Nas2 PDZ domain has been determined. The 26S proteasome is a 2.5 MDa protease dedicated to the degradation of ubiquitinated proteins in eukaryotes. The assembly of this complex containing 66 polypeptides is assisted by at least nine proteasome-specific chaperones. One of these, Nas2, binds to the proteasomal AAA-ATPase subunit Rpt5. The PDZ domain of Nas2 binds to the C-terminal tail of Rpt5; however, it does not require the C-terminus of Rpt5 for binding. Here, the 1.15 Å resolution structure of the PDZ domain of Nas2 is reported. This structure will provide a basis for further insights regarding the structure and function of Nas2 in proteasome assembly.

  5. Multiple sclerosis autoantigen myelin basic protein escapes control by ubiquitination during proteasomal degradation.

    Science.gov (United States)

    Belogurov, Alexey; Kudriaeva, Anna; Kuzina, Ekaterina; Smirnov, Ivan; Bobik, Tatyana; Ponomarenko, Natalia; Kravtsova-Ivantsiv, Yelena; Ciechanover, Aaron; Gabibov, Alexander

    2014-06-20

    The vast majority of cellular proteins are degraded by the 26S proteasome after their ubiquitination. Here, we report that the major component of the myelin multilayered membrane sheath, myelin basic protein (MBP), is hydrolyzed by the 26S proteasome in a ubiquitin-independent manner both in vitro and in mammalian cells. As a proteasomal substrate, MBP reveals a distinct and physiologically relevant concentration range for ubiquitin-independent proteolysis. Enzymatic deimination prevents hydrolysis of MBP by the proteasome, suggesting that an abnormally basic charge contributes to its susceptibility toward proteasome-mediated degradation. To our knowledge, our data reveal the first case of a pathophysiologically important autoantigen as a ubiquitin-independent substrate of the 26S proteasome.

  6. Calcium-dependent proteasome activation is required for axonal neurofilament degradation.

    Science.gov (United States)

    Park, Joo Youn; Jang, So Young; Shin, Yoon Kyung; Suh, Duk Joon; Park, Hwan Tae

    2013-12-25

    Even though many studies have identified roles of proteasomes in axonal degeneration, the molecular mechanisms by which axonal injury regulates proteasome activity are still unclear. In the present study, we found evidence indicating that extracellular calcium influx is an upstream regulator of proteasome activity during axonal degeneration in injured peripheral nerves. In degenerating axons, the increase in proteasome activity and the degradation of ubiquitinated proteins were significantly suppressed by extracellular calcium chelation. In addition, electron microscopic findings revealed selective inhibition of neurofilament degradation, but not microtubule depolymerization or mitochondrial swelling, by the inhibition of calpain and proteasomes. Taken together, our findings suggest that calcium increase and subsequent proteasome activation are an essential initiator of neurofilament degradation in Wallerian degeneration. PMID:25206662

  7. Calcium-dependent proteasome activation is required for axonal neurofilament degradation

    Institute of Scientific and Technical Information of China (English)

    Joo Youn Park; So Young Jang; Yoon Kyung Shin; Duk Joon Suh; Hwan Tae Park

    2013-01-01

    Even though many studies have identified roles of proteasomes in axonal degeneration, the mo-lecular mechanisms by which axonal injury regulates proteasome activity are stil unclear. In the present study, we found evidence indicating that extracellular calcium influx is an upstream regula-tor of proteasome activity during axonal degeneration in injured peripheral nerves. In degenerating axons, the increase in proteasome activity and the degradation of ubiquitinated proteins were sig-nificantly suppressed by extracellular calcium chelation. In addition, electron microscopic findings revealed selective inhibition of neurofilament degradation, but not microtubule depolymerization or mitochondrial swel ing, by the inhibition of calpain and proteasomes. Taken together, our findings suggest that calcium increase and subsequent proteasome activation are an essential initiator of neurofilament degradation in Wal erian degeneration.

  8. Cells Sensing Mechanical Cues: Stiffness Influences the Lifetime of Cell-Extracellular Matrix Interactions by Affecting the Loading Rate.

    Science.gov (United States)

    Jiang, Li; Sun, Zhenglong; Chen, Xiaofei; Li, Jing; Xu, Yue; Zu, Yan; Hu, Jiliang; Han, Dong; Yang, Chun

    2016-01-26

    The question of how cells sense substrate mechanical cues has gained increasing attention among biologists. By introducing contour-based data analysis to single-cell force spectroscopy, we identified a loading-rate threshold for the integrin α2β1-DGEA bond beyond which a dramatic increase in bond lifetime was observed. On the basis of mechanical cues (elasticity or topography), the effective spring constant of substrates k is mapped to the loading rate r under actomyosin pulling speed v, which, in turn, affects the lifetime of the integrin-ligand bond. Additionally, downregulating v with a low-dose blebbistatin treatment promotes the neuronal lineage specification of mesenchymal stem cells on osteogenic stiff substrates. Thus, sensing of the loading rate is central to how cells sense mechanical cues that affect cell-extracellular matrix interactions and stem cell differentiation.

  9. GxE Interactions Between FOXO Genotypes and Tea Drinking Significantly Affect Cognitive Disability at Advanced Ages in China

    DEFF Research Database (Denmark)

    Zeng, Yi; Chen, Huashuai; Ni, Ting;

    2014-01-01

    Logistic regression analysis based on data from 822 Han Chinese oldest old aged 92+ demonstrated that interactions between carrying FOXO1A-266 or FOXO3-310 or FOXO3-292 and tea drinking at around age 60 or at present time were significantly associated with lower risk of cognitive disability...... age 60, and at present time. Based on prior findings from animal and human cell models, we postulate that intake of tea compounds may activate FOXO gene expression, which in turn may positively affect cognitive function in the oldest old population. Our empirical findings imply that the health...... at advanced ages. Associations between tea drinking and reduced cognitive disability were much stronger among carriers of the genotypes of FOXO1A-266 or FOXO3-310 or FOXO3-292 compared with noncarriers, and it was reconfirmed by analysis of three-way interactions across FOXO genotypes, tea drinking at around...

  10. Profiling human protein degradome delineates cellular responses to proteasomal inhibition and reveals a feedback mechanism in regulating proteasome homeostasis

    OpenAIRE

    Yu, Tao; Tao, Yonghui; Yang, Meiqiang; Chen, Peng; Gao, XiaoBo; Zhang, Yanbo; Zhang,Tao; Chen, Zi; Hou, Jian; Zhang, Yan; Ruan, Kangcheng; Wang, Hongyan; Hu, Ronggui

    2014-01-01

    Global change in protein turnover (protein degradome) constitutes a central part of cellular responses to intrinsic or extrinsic stimuli. However, profiling protein degradome remains technically challenging. Recently, inhibition of the proteasome, e.g., by using bortezomib (BTZ), has emerged as a major chemotherapeutic strategy for treating multiple myeloma and other human malignancies, but systematic understanding of the mechanisms for BTZ drug action and tumor drug resistance is yet to be a...

  11. Does vegetation complexity affect host plant chemistry, and thus multitrophic interactions, in a human-altered landscape?

    Science.gov (United States)

    Wäschke, Nicole; Hancock, Christine; Hilker, Monika; Obermaier, Elisabeth; Meiners, Torsten

    2015-09-01

    Anthropogenic land use may shape vegetation composition and affect trophic interactions by altering concentrations of host plant metabolites. Here, we investigated the hypotheses that: (1) plant N and defensive secondary metabolite contents of the herb Plantago lanceolata are affected by land use intensity (LUI) and the surrounding vegetation composition (=plant species richness and P. lanceolata density), and that (2) changes in plant chemistry affect abundances of the herbivorous weevils Mecinus pascuorum and Mecinus labilis, as well as their larval parasitoid Mesopolobus incultus, in the field. We determined plant species richness, P. lanceolata density, and abundances of the herbivores and the parasitoid in 77 grassland plots differing in LUI index in three regions across Germany. We also measured the N and secondary metabolite [the iridoid glycosides (IGs) aucubin and catalpol] contents of P. lanceolata leaves. Mixed-model analysis revealed that: (1) concentrations of leaf IGs were positively correlated with plant species richness; leaf N content was positively correlated with the LUI index. Furthermore: (2) herbivore abundance was not related to IG concentrations, but correlated negatively with leaf N content. Parasitoid abundance correlated positively only with host abundance over the three regions. Structural equation models revealed a positive impact of IG concentrations on parasitoid abundance in one region. We conclude that changes in plant chemistry due to land use and/or vegetation composition may affect higher trophic levels and that the manifestation of these effects may depend on local biotic or abiotic features of the landscape. PMID:25986560

  12. Influences of a Socially Interactive Robot on the Affective Behavior of Young Children with Disabilities. Social Robots Research Reports, Number 3

    Science.gov (United States)

    Dunst, Carl J.; Prior, Jeremy; Hamby, Deborah W.; Trivette, Carol M.

    2013-01-01

    Findings from two studies of 11 young children with autism, Down syndrome, or attention deficit disorders investigating the effects of Popchilla, a socially interactive robot, on the children's affective behavior are reported. The children were observed under two conditions, child-toy interactions and child-robot interactions, and ratings of child…

  13. Plasma membrane lipid-protein interactions affect signaling processes in sterol-biosynthesis mutants of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Henrik eZauber

    2014-03-01

    Full Text Available The plasma membrane is an important organelle providing structure, signaling and transport as major biological functions. Being composed of lipids and proteins with different physicochemical properties, the biological functions of membranes depend on specific protein-protein and protein-lipid interactions. Interactions of proteins with their specific sterol and lipid environment were shown to be important factors for protein recruitment into sub-compartmental structures of the plasma membrane. System-wide implications of altered endogenous sterol levels for membrane functions in living cells were not studied in higher plant cells. In particular, little is known how alterations in membrane sterol composition affect protein and lipid organization and interaction within membranes. Here, we conducted a comparative analysis of the plasma membrane protein and lipid composition in Arabidopsis sterol-biosynthesis mutants smt1 and ugt80A2;B1. smt1 shows general alterations in sterol composition while ugt80A2;B1 is significantly impaired in sterol glycosylation. By systematically analyzing different cellular fractions and combining proteomic with lipidomic data we were able to reveal contrasting alterations in lipid-protein interactions in both mutants, with resulting differential changes in plasma membrane signaling status.

  14. The proteasome cap RPT5/Rpt5p subunit prevents aggregation of unfolded ricin A chain

    DEFF Research Database (Denmark)

    Pietroni, Paola; Vasisht, Nishi; Cook, Jonathan P;

    2013-01-01

    model is that the bulk of ER-dislocated RTA is degraded by proteasomes. We show here that the proteasome has a more complex role in ricin intoxication than previously recognised, that the previously reported increase in sensitivity of mammalian cells to ricin in the presence of proteasome inhibitors......5p in the triage of substrates in which either activation (folding) or inactivation (degradation) pathways may be initiated....

  15. Clinical Use of Proteasome Inhibitors in the Treatment of Multiple Myeloma

    Directory of Open Access Journals (Sweden)

    Noah M. Merin

    2014-12-01

    Full Text Available Multiple myeloma (MM is an incurable hematological malignancy characterized by the clonal proliferation of neoplastic plasma cells. The use of proteasome inhibitors in the treatment of MM has led to significant improvements in outcomes. This article reviews data on the use of the two approved proteasome inhibitors (bortezomib and carlfilzomib, as well as newer agents under development. Emphasis is placed on the clinical use of proteasome inhibitors, including management of side effects and combination with other agents.

  16. Complex trait subtypes identification using transcriptome profiling reveals an interaction between two QTL affecting adiposity in chicken

    Directory of Open Access Journals (Sweden)

    Blum Yuna

    2011-11-01

    Full Text Available Abstract Background Integrative genomics approaches that combine genotyping and transcriptome profiling in segregating populations have been developed to dissect complex traits. The most common approach is to identify genes whose eQTL colocalize with QTL of interest, providing new functional hypothesis about the causative mutation. Another approach includes defining subtypes for a complex trait using transcriptome profiles and then performing QTL mapping using some of these subtypes. This approach can refine some QTL and reveal new ones. In this paper we introduce Factor Analysis for Multiple Testing (FAMT to define subtypes more accurately and reveal interaction between QTL affecting the same trait. The data used concern hepatic transcriptome profiles for 45 half sib male chicken of a sire known to be heterozygous for a QTL affecting abdominal fatness (AF on chromosome 5 distal region around 168 cM. Results Using this methodology which accounts for hidden dependence structure among phenotypes, we identified 688 genes that are significantly correlated to the AF trait and we distinguished 5 subtypes for AF trait, which are not observed with gene lists obtained by classical approaches. After exclusion of one of the two lean bird subtypes, linkage analysis revealed a previously undetected QTL on chromosome 5 around 100 cM. Interestingly, the animals of this subtype presented the same q paternal haplotype at the 168 cM QTL. This result strongly suggests that the two QTL are in interaction. In other words, the "q configuration" at the 168 cM QTL could hide the QTL existence in the proximal region at 100 cM. We further show that the proximal QTL interacts with the previous one detected on the chromosome 5 distal region. Conclusion Our results demonstrate that stratifying genetic population by molecular phenotypes followed by QTL analysis on various subtypes can lead to identification of novel and interacting QTL.

  17. The blues of adolescent romance: observed affective interactions in adolescent romantic relationships associated with depressive symptoms.

    Science.gov (United States)

    Ha, Thao; Dishion, Thomas J; Overbeek, Geertjan; Burk, William J; Engels, Rutger C M E

    2014-05-01

    We examined the associations between observed expressions of positive and negative emotions during conflict discussions and depressive symptoms during a 2-year period in a sample of 160 adolescents in 80 romantic relationships (M age = 15.48, SD = 1.16). Conflict discussions were coded using the 10-code Specific Affect Coding System. Depressive symptoms were assessed at the time of the observed conflict discussions (Time 1) and 2 years later (Time 2). Data were analyzed using actor-partner interdependence models. Girls' expression of both positive and negative emotions at T1 was related to their own depressive symptoms at T2 (actor effect). Boys' positive emotions and negative emotions (actor effect) and girls' negative emotions (partner effect) were related to boys' depressive symptoms at T2. Contrary to expectation, relationship break-up and relationship satisfaction were unrelated to changes in depressive symptoms or expression of negative or positive emotion during conflict discussion. These findings underscore the unique quality of adolescent romantic relationships and suggest new directions in the study of the link between mental health and romantic involvement in adolescence.

  18. Toxic metal interactions affect the bioaccumulation and dietary intake of macro- and micro-nutrients.

    Science.gov (United States)

    Khan, Anwarzeb; Khan, Sardar; Alam, Mehboob; Khan, Muhammad Amjad; Aamir, Muhammad; Qamar, Zahir; Ur Rehman, Zahir; Perveen, Sajida

    2016-03-01

    The present study was conducted to evaluate the effects of heavy metals (cadmium (Cd), lead (Pb) and Cd-Pb mix) on bioaccumulation of different nutrients. Three plant species including potato, tomato and lettuce were grown in pots containing soil contaminated with Cd, Pb and Cd-Pb mix at four different levels. The edible portions of each plant were analysed for Cd, Pb and different macro- and micro-nutrients including protein, vitamin C, nitrogen (N), phosphorous (P), potassium (K), iron (Fe), manganese (Mn), calcium (Ca) and magnesium (Mg). Results indicated significant variations in selected elemental concentrations in all the three plants grown in different treatments. The projected daily dietary intake values of selected metals were significant (P < 0.001) for Fe, Mn, Ca and Mg but not significant for protein, vitamin C, N and P. The elemental contribution to Recommended Dietary Allowance (RDA) was significant for Mn. Similarly, Fe and Mg also showed substantial contribution to RDA, while Ca, N, P, K, protein and vitamin C showed the minimal contribution for different age groups. This study suggests that vegetables cultivated on Cd and Pb contaminated soil may significantly affect their quality, and the consumption of such vegetables may result in substantial negative effects on nutritional composition of the consumer body. Long term and continuous use of contaminated vegetables may result in malnutrition.

  19. Some factors affecting the dynamics of a plasma-wall interaction simulator

    International Nuclear Information System (INIS)

    Isotope mixing and thermal desorption from samples exposed in a glow discharge apparatus were used to study the factors affecting hydrogen recycle and wall inventory. Conditions were chosen to be similar to those expected at the walls in today's experimental fusion devices. The size and nature of the hydrogen reservoir in the wall after plasma pulses was investigated by thermal desorption techniques. Large amounts of deuterium, i.e., 5 x 1015 D cm-2 remain in the sample 4 min after a single 200 ms plasma pulse. While this result may be explained by a model using bulk diffusion and traps, it is suggested that either a spectrum of desorption energies, or a concentration dependent recombination coefficient, may also be useful in describing the thermal desorption processes. Experiments with various pumping conditions show that readsorption of molecular hydrogen isotopes on the wall should be considered in modeling hydrogen recycle and isotope changeover processes. HD formation without plasmas confirms the role readsorption plays. (orig.)

  20. Ecology of conflict: marine food supply affects human-wildlife interactions on land

    Science.gov (United States)

    Artelle, Kyle A.; Anderson, Sean C.; Reynolds, John D.; Cooper, Andrew B.; Paquet, Paul C.; Darimont, Chris T.

    2016-01-01

    Human-wildlife conflicts impose considerable costs to people and wildlife worldwide. Most research focuses on proximate causes, offering limited generalizable understanding of ultimate drivers. We tested three competing hypotheses (problem individuals, regional population saturation, limited food supply) that relate to underlying processes of human-grizzly bear (Ursus arctos horribilis) conflict, using data from British Columbia, Canada, between 1960–2014. We found most support for the limited food supply hypothesis: in bear populations that feed on spawning salmon (Oncorhynchus spp.), the annual number of bears/km2 killed due to conflicts with humans increased by an average of 20% (6–32% [95% CI]) for each 50% decrease in annual salmon biomass. Furthermore, we found that across all bear populations (with or without access to salmon), 81% of attacks on humans and 82% of conflict kills occurred after the approximate onset of hyperphagia (July 1st), a period of intense caloric demand. Contrary to practices by many management agencies, conflict frequency was not reduced by hunting or removal of problem individuals. Our finding that a marine resource affects terrestrial conflict suggests that evidence-based policy for reducing harm to wildlife and humans requires not only insight into ultimate drivers of conflict, but also management that spans ecosystem and jurisdictional boundaries. PMID:27185189

  1. Working with interpreters: how student behavior affects quality of patient interaction when using interpreters

    Directory of Open Access Journals (Sweden)

    Cha-Chi Fung

    2010-06-01

    Full Text Available Background: Despite the prevalence of medical interpreting in the clinical environment, few medical professionals receive training in best practices when using an interpreter. We designed and implemented an educational workshop on using interpreters as part of the cultural competency curriculum for second year medical students (MSIIs at David Geffen School of Medicine at UCLA. The purpose of this study is two-fold: first, to evaluate the effectiveness of the workshop and second, if deficiencies are found, to investigate whether the deficiencies affected the quality of the patient encounter when using an interpreter. Methods: A total of 152 MSIIs completed the 3-hour workshop and a 1-station objective-structured clinical examination, 8 weeks later to assess skills. Descriptive statistics and independent sample t-tests were used to assess workshop effectiveness. Results: Based on a passing score of 70%, 39.4% of the class failed. Two skills seemed particularly problematic: assuring confidentiality (missed by 50% and positioning the interpreter (missed by 70%. While addressing confidentiality did not have a significant impact on standardized patient satisfaction, interpreter position did. Conclusion: Instructing the interpreter to sit behind the patient helps sustain eye contact between clinician and patient, while assuring confidentiality is a tenet of quality clinical encounters. Teaching students and faculty to emphasize both is warranted to improve cross-language clinical encounters.

  2. Ecology of conflict: marine food supply affects human-wildlife interactions on land.

    Science.gov (United States)

    Artelle, Kyle A; Anderson, Sean C; Reynolds, John D; Cooper, Andrew B; Paquet, Paul C; Darimont, Chris T

    2016-01-01

    Human-wildlife conflicts impose considerable costs to people and wildlife worldwide. Most research focuses on proximate causes, offering limited generalizable understanding of ultimate drivers. We tested three competing hypotheses (problem individuals, regional population saturation, limited food supply) that relate to underlying processes of human-grizzly bear (Ursus arctos horribilis) conflict, using data from British Columbia, Canada, between 1960-2014. We found most support for the limited food supply hypothesis: in bear populations that feed on spawning salmon (Oncorhynchus spp.), the annual number of bears/km(2) killed due to conflicts with humans increased by an average of 20% (6-32% [95% CI]) for each 50% decrease in annual salmon biomass. Furthermore, we found that across all bear populations (with or without access to salmon), 81% of attacks on humans and 82% of conflict kills occurred after the approximate onset of hyperphagia (July 1(st)), a period of intense caloric demand. Contrary to practices by many management agencies, conflict frequency was not reduced by hunting or removal of problem individuals. Our finding that a marine resource affects terrestrial conflict suggests that evidence-based policy for reducing harm to wildlife and humans requires not only insight into ultimate drivers of conflict, but also management that spans ecosystem and jurisdictional boundaries. PMID:27185189

  3. Salts affect the interaction of ZnO or CuO nanoparticles with wheat.

    Science.gov (United States)

    Stewart, Jacob; Hansen, Trevor; McLean, Joan E; McManus, Paul; Das, Siddhartha; Britt, David W; Anderson, Anne J; Dimkpa, Christian O

    2015-09-01

    Exposure to nanoparticles (NPs) that release metals with potential phytotoxicity could pose problems in agriculture. The authors of the present study used growth in a model growth matrix, sand, to examine the influence of 5 mmol/kg of Na, K, or Ca (added as Cl salts) and root exudates on transformation and changes to the bioactivity of copper(II) oxide (CuO) and zinc oxide (ZnO) NPs on wheat. These salt levels are found in saline agricultural soils. After 14 d of seedling growth, particles with crystallinity typical of CuO or ZnO remained in the aqueous fraction from the sand; particles had negative surface charges that differed with NP type and salt, but salt did not alter particle agglomeration. Reduction in shoot and root elongation and lateral root induction by ZnO NPs were mitigated by all salts. However, whereas Na and K promoted Zn loading into shoots, Ca reduced loading, suggesting that competition with Zn ions for uptake occurred. With CuO NPs, plant growth and loading was modified equally by all salts, consistent with major interaction with the plant with CuO rather than Cu ions. Thus, for both NPs, loading into plant tissues was not solely dependent on ion solubility. These findings indicated that salts in agricultural soils could modify the phytotoxicity of NPs.

  4. The interactive effects of affect and shopping goal on information search and product evaluations.

    Science.gov (United States)

    Chen, Fangyuan; Wyer, Robert S; Shen, Hao

    2015-12-01

    Although shoppers often want to evaluate products to make a purchase decision, they can also shop for enjoyment. In each case, the amount of time they spend on shopping and the number of options they consider can depend on the mood they happen to be in. We predicted that mood can signal whether the goal has been attained and when people should stop processing information. When people are primarily motivated to purchase a particular type of product, positive mood signals that they have done enough. Thus, they consider less information if they are happy than if they are unhappy. When people shop for enjoyment, however, positive mood signals that they are still having fun. Thus, they consider more information when they are happy than when they are not. Four experiments among university students (N = 827) examined these possibilities. Experiment 1 provided initial evidence for the interactive effects of mood and goals on search behavior and product evaluation. Other studies examined the implications of this conceptualization for different domains: (a) the relative impact of brand and attribute information on judgments (Experiment 2), (b) gender differences in shopping behavior (Experiment 3), and (c) the number of options that people review in an actual online shopping website (Experiment 4). PMID:26460676

  5. Structural analysis of the dodecameric proteasome activator PafE in Mycobacterium tuberculosis.

    Science.gov (United States)

    Bai, Lin; Hu, Kuan; Wang, Tong; Jastrab, Jordan B; Darwin, K Heran; Li, Huilin

    2016-04-01

    The human pathogen Mycobacterium tuberculosis (Mtb) requires a proteasome system to cause lethal infections in mice. We recently found that proteasome accessory factor E (PafE, Rv3780) activates proteolysis by the Mtb proteasome independently of adenosine triphosphate (ATP). Moreover, PafE contributes to the heat-shock response and virulence of Mtb Here, we show that PafE subunits formed four-helix bundles similar to those of the eukaryotic ATP-independent proteasome activator subunits of PA26 and PA28. However, unlike any other known proteasome activator, PafE formed dodecamers with 12-fold symmetry, which required a glycine-XXX-glycine-XXX-glycine motif that is not found in previously described activators. Intriguingly, the truncation of the PafE carboxyl-terminus resulted in the robust binding of PafE rings to native proteasome core particles and substantially increased proteasomal activity, suggesting that the extended carboxyl-terminus of this cofactor confers suboptimal binding to the proteasome core particle. Collectively, our data show that proteasomal activation is not limited to hexameric ATPases in bacteria. PMID:27001842

  6. The ubiquitin-proteasome system is a key component of the SUMO-2/3 cycle

    DEFF Research Database (Denmark)

    Schimmel, Joost; Larsen, Katja M; Matic, Ivan;

    2008-01-01

    proteomics experiments enabled the identification of 73 SUMO-2 conjugated proteins that accumulated in cells treated with proteasome inhibitors. Crosstalk between SUMO-2/3 and the ubiquitin-proteasome system controls many target proteins that regulate all aspects of nucleic acid metabolism. Surprisingly......, the relative abundance of 40 SUMO-2 conjugated proteins was reduced by proteasome inhibitors, possibly due to a lack of recycled SUMO-2. We conclude that SUMO-2/3 conjugation and the ubiquitin-proteasome system are tightly integrated and act in a cooperative manner....

  7. Different effect of proteasome inhibition on vesicular stomatitis virus and poliovirus replication.

    Directory of Open Access Journals (Sweden)

    Nickolay Neznanov

    Full Text Available Proteasome activity is an important part of viral replication. In this study, we examined the effect of proteasome inhibitors on the replication of vesicular stomatitis virus (VSV and poliovirus. We found that the proteasome inhibitors significantly suppressed VSV protein synthesis, virus accumulation, and protected infected cells from toxic effect of VSV replication. In contrast, poliovirus replication was delayed, but not diminished in the presence of the proteasome inhibitors MG132 and Bortezomib. We also found that inhibition of proteasomes stimulated stress-related processes, such as accumulation of chaperone hsp70, phosphorylation of eIF2alpha, and overall inhibition of translation. VSV replication was sensitive to this stress with significant decline in replication process. Poliovirus growth was less sensitive with only delay in replication. Inhibition of proteasome activity suppressed cellular and VSV protein synthesis, but did not reduce poliovirus protein synthesis. Protein kinase GCN2 supported the ability of proteasome inhibitors to attenuate general translation and to suppress VSV replication. We propose that different mechanisms of translational initiation by VSV and poliovirus determine their sensitivity to stress induced by the inhibition of proteasomes. To our knowledge, this is the first study that connects the effect of stress induced by proteasome inhibition with the efficiency of viral infection.

  8. The CHUVA Project Contributions to the Understanding of Anthropogenic Interactions Affecting the Atmospheric Physics over Amazonas.

    Science.gov (United States)

    Maroon, E.; Frierson, D. M.; Kang, S. M.; Scheff, J.; Battisti, D. S.

    2014-12-01

    Greater precipitation falls in the northern hemisphere (NH) tropics than in the southern hemisphere (SH) tropics over the course of the year. Here, we examine how Andes topography, ocean heat fluxes, and the presence of land affect the location of tropical precipitation in an idealized aquaplanet version of GFDL's AM2.1 GCM. We find that all three of these features influence which hemisphere has greater precipitation, though to different extents. The addition of Andes topography leads to a small regional northward shift of rainfall, but realistic ocean heat transport leads to a much larger and more global northward shift of precipitation. In simulations with an idealized NH subtropical continent, the location of tropical precipitation depends on the land albedo and continent width. To demonstrate this, we place a single Sahara-like rectangular continent with a width of 60-degrees and an albedo of 0.3 into the NH. This simulation has greater SH tropical precipitation, despite the NH continent's hot surface: the high land albedo increases the NH deficit of energy, creating an anomalous Hadley circulation that imports energy to the NH and moisture to the SH. As a result, the hemisphere with greater temperature is not the hemisphere with greater precipitation. However, simulations with wider continents and the same fixed albedo shift precipitation into the NH as the continent widens. While northward ocean heat transport is likely the reason for the observed annual NH peak in tropical precipitation, these experiments show that continents and topography also play an important role in modifying its location.

  9. Nutrient Deprivation Affects Salmonella Invasion and Its Interaction with the Gastrointestinal Microbiota.

    Directory of Open Access Journals (Sweden)

    Sophie Yurist-Doutsch

    Full Text Available Salmonella enterica serovar Typhimurium (S. Typhimurium is a foodborne enteric pathogen and a major cause of gastroenteritis in humans. It is known that molecules derived from the human fecal microbiota downregulate S. Typhimurium virulence gene expression and induce a starvation-like response. In this study, S. Typhimurium was cultured in minimal media to mimic starvation conditions such as that experienced by S. Typhimurium in the human intestinal tract, and the pathogen's virulence in vitro and in vivo was measured. S. Typhimurium cultured in minimal media displayed a reduced ability to invade human epithelial cells in a manner that was at least partially independent of the Salmonella Pathogenicity Island 1 (SPI-1 type III secretion system. Nutrient deprivation did not, however, alter the ability of S. Typhimurium to replicate and survive inside epithelial cells. In a murine model of S. Typhimurium-induced gastroenteritis, prior cultivation in minimal media did not alter the pathogen's ability to colonize mice, nor did it affect levels of gastrointestinal inflammation. Upon examining the post-infection fecal gastrointestinal microbiota, we found that specifically in the 129Sv/ImJ murine strain S. Typhimurium cultured in minimal media induced differential microbiota compositional shifts compared to that of S. Typhimurium cultured in rich media. Together these findings demonstrate that S. Typhimurium remains a potent pathogen even in the face of nutritional deprivation, but nevertheless that nutrient deprivation encountered in this environment elicits significant changes in the bacterium genetic programme, as well as its capacity to alter host microbiota composition.

  10. Neurophysiological processing of emotion and parenting interact to predict inhibited behavior: an affective-motivational framework.

    Science.gov (United States)

    Kessel, Ellen M; Huselid, Rebecca F; Decicco, Jennifer M; Dennis, Tracy A

    2013-01-01

    Although inhibited behavior problems are prevalent in childhood, relatively little is known about the intrinsic and extrinsic factors that predict a child's ability to regulate inhibited behavior during fear- and anxiety-provoking tasks. Inhibited behavior may be linked to both disruptions in avoidance-related processing of aversive stimuli and in approach-related processing of appetitive stimuli, but previous findings are contradictory and rarely integrate consideration of the socialization context. The current exploratory study used a novel combination of neurophysiological and observation-based methods to examine whether a neurophysiological measure sensitive to approach- and avoidance-oriented emotional processing, the late positive potential (LPP), interacted with observed approach- (promotion) and avoidance- (prevention) oriented parenting practices to predict children's observed inhibited behavior. Participants were 5- to 7-year-old (N = 32) typically-developing children (M = 75.72 months, SD = 6.01). Electroencephalography was continuously recorded while children viewed aversive, appetitive, or neutral images, and the LPP was generated to each picture type separately. Promotion and prevention parenting were observed during an emotional challenge with the child. Child inhibited behavior was observed during a fear and a social evaluation task. As predicted, larger LPPs to aversive images predicted more inhibited behavior during both tasks, but only when parents demonstrated low promotion. In contrast, larger LPPs to appetitive images predicted less inhibited behavior during the social evaluative task, but only when parents demonstrated high promotion; children of high promotion parents showing smaller LPPs to appetitive images showed the greatest inhibition. Parent-child goodness-of-fit and the LPP as a neural biomarker for emotional processes related to inhibited behavior are discussed. PMID:23847499

  11. Neurophysiological Processing of Emotion and Parenting Interact to Predict Inhibited Behavior: An Affective-Motivational Framework

    Directory of Open Access Journals (Sweden)

    Ellen M Kessel

    2013-07-01

    Full Text Available Although inhibited behavior problems are prevalent in childhood, relatively little is known about the intrinsic and extrinsic factors that predict a child’s ability to regulate inhibited behavior during fear- and anxiety-provoking tasks. Inhibited behavior may be linked to both disruptions in avoidance-related processing of aversive stimuli and in approach-related processing of appetitive stimuli, but previous findings are contradictory and rarely integrate consideration of the socialization context. The current exploratory study used a novel combination of neurophysiological and observation-based methods to examine whether a neurophysiological measure sensitive to approach- and avoidance-oriented emotional processing, the late positive potential (LPP, interacted with observed approach- (promotion and avoidance- (prevention oriented parenting practices to predict children’s observed inhibited behavior. Participants were 5- to 7-year-old (N = 32 typically-developing children (M = 75.72 months, SD = 6.01. Electroencephalography was continuously recorded while children viewed aversive, appetitive, or neutral images, and the LPP was generated to each picture type separately. Promotion and prevention parenting were observed during an emotional challenge with the child. Child inhibited behavior was observed during a fear and a social evaluation task. As predicted, larger LPPs to aversive images predicted more inhibited behavior during both tasks, but only when parents demonstrated low promotion. In contrast, larger LPPs to appetitive images predicted less inhibited behavior during the social evaluative task, but only when parents demonstrated high promotion; children of high promotion parents showing smaller LPPs to appetitive images showed the greatest inhibition. Parent-child goodness-of-fit and the LPP as a neural biomarker for emotional processes related to inhibited behavior are discussed.

  12. Benthic Trophic Interactions in an Antarctic Shallow Water Ecosystem Affected by Recent Glacier Retreat.

    Directory of Open Access Journals (Sweden)

    Francesca Pasotti

    Full Text Available The western Antarctic Peninsula is experiencing strong environmental changes as a consequence of ongoing regional warming. Glaciers in the area are retreating rapidly and increased sediment-laden meltwater runoff threatens the benthic biodiversity at shallow depths. We identified three sites with a distinct glacier-retreat related history and different levels of glacial influence in the inner part of Potter Cove (King George Island, South Shetland Islands, a fjord-like embayment impacted since the 1950s by a tidewater glacier retreat. We compared the soft sediment meio- and macrofauna isotopic niche widths (δ13C and δ15N stable isotope analysis at the three sites to investigate possible glacier retreat-related influences on benthic trophic interactions. The isotopic niches were locally shaped by the different degrees of glacier retreat-related disturbance within the Cove. Wider isotopic niche widths were found at the site that has become ice-free most recently, and narrower niches at the older ice-free sites. At an intermediate state of glacier retreat-related disturbance (e.g. via ice-growler scouring species with different strategies could settle. The site at the earliest stage of post-retreat development was characterized by an assemblage with lower trophic redundancy. Generally, the isotopic niche widths increased with increasing size spectra of organisms within the community, excepting the youngest assemblage, where the pioneer colonizer meiofauna size class displayed the highest isotopic niche width. Meiofauna at all sites generally occupied positions in the isotopic space that suggested a detrital-pool food source and/or the presence of predatory taxa. In general ice scour and glacial impact appeared to play a two-fold role within the Cove: i either stimulating trophic diversity by allowing continuous re-colonization of meiofaunal species or, ii over time driving the benthic assemblages into a more compact trophic structure with

  13. Schwann cell interactions with polymer films are affected by groove geometry and film hydrophilicity.

    Science.gov (United States)

    Mobasseri, S A; Terenghi, G; Downes, S

    2014-10-01

    We have developed a biodegradable polymer scaffold made of a polycaprolactone/polylactic acid (PCL/PLA) film. Surface properties such as topography and chemistry have a vital influence on cell-material interactions. Surface modifications of PCL/PLA films were performed using topographical cues and UV-ozone treatment to improve Schwann cell organisation and behaviour. Schwann cell attachment, alignment and proliferation were evaluated on the grooved UV-ozone treated and non-treated films. Solvent casting of the polymer solution on patterned silicon substrates resulted in films with different groove shapes: V (V), sloped (SL) and square (SQ) shapes. Pitted films, with no grooves, were prepared as a negative control. The UV-ozone treatment was performed to increase hydrophilicity. The process specifications for UV-ozone treatment were evaluated and 5 min radiation time and 6 cm distance to the UV source were suggested as the optimal practise. When cultured on grooved films, Schwann cells elongated on the V and SL shape grooves without crossing over, and grew in the direction of the grooves. However, there was less elongation with more crossing over on the SQ shape grooves. The maximum cell length (511 μm) was observed on the treated V-grooved films. The cells cultured on pitted UV-ozone treated surfaces showed random arrangements with no increase in length. We have demonstrated that the synergic effects of physical cues combined with UV-ozone treatment have the potential to enhance Schwann cell morphology and alignment. PMID:25167538

  14. Interactions between Coniothyrium minitans and Sclerotinia minor affect biocontrol efficacy of C. minitans.

    Science.gov (United States)

    Chitrampalam, P; Wu, B M; Koike, S T; Subbarao, K V

    2011-03-01

    Coniothyrium minitans, marketed as Contans, has become a standard management tool against Sclerotinia sclerotiorum in a variety of crops, including winter lettuce. However, it has been ineffective against lettuce drop caused by S. minor. The interactions between C. minitans and S minor were investigated to determine the most susceptible stage in culture to attack by C. minitans, and to determine its consistency on S minor isolates belonging to four major mycelial compatibility groups (MCGs). Four isolates of S. minor MCG 1 and 5 each from MCGs 2 and 3 and one from MCG 4 were treated in culture at purely mycelial, a few immature sclerotial, and fully mature sclerotial phases with a conidial suspension of C. minitans. Sclerotia from all treatments were harvested after 4 weeks, air dried, weighed, and plated on potato dextrose agar for recovery of C. minitans. S. minor formed the fewest sclerotia in plates that received C. minitans at the mycelial stage; C. minitans was recovered from nearly all sclerotia from this treatment and sclerotial mortality was total. However, the response of MCGs was inconsistent and variable. Field experiments to determine the efficacy of C. minitans relative to the registered fungicide, Endura, on lettuce drop incidence and soil inoculum dynamics were conducted from 2006 to 2009. All Contans treatments had significantly lower numbers of sclerotia than Endura and unsprayed control treatments, and drop incidence was as low as in Endura-treated plots (P > 0.05). Although the lower levels of lettuce drop in Contans treatments were correlated with significantly lower levels of sclerotia, the lower levels of lettuce drop, despite the presence of higher inoculum in the Endura treatment, was attributable to the prevention of infection by S. minor. A useful approach to sustained lettuce drop management is to employ Contans to lower the number of sclerotia in soil and to apply Endura to prevent S. minor infection within a cropping season. PMID

  15. Rootstock-scion interaction affecting citrus response to CTV infection: a proteomic view.

    Science.gov (United States)

    Laino, Paolo; Russo, Maria P; Guardo, Maria; Reforgiato-Recupero, Giuseppe; Valè, Giampiero; Cattivelli, Luigi; Moliterni, Vita M C

    2016-04-01

    Citrus tristeza virus (CTV) is the causal agent of various diseases with dramatic effects on citrus crops worldwide. Most Citrus species, grown on their own roots, are symptomless hosts for many CTV isolates. However, depending on different scion-rootstock combination, CTV infection should result in distinct syndromes, being 'tristeza' the more severe one, leading to a complete decline of the susceptible plants in a few weeks. Transcriptomic analyses revealed several genes involved either in defense response, or systemic acquired resistance, as well as transcription factors and components of the phosphorylation cascades, to be differentially regulated during CTV infection in Citrus aurantifolia species. To date little is known about the molecular mechanism of this host-pathogen interaction, and about the rootstock effect on citrus response to CTV infection. In this work, the response to CTV infection has been investigated in tolerant and susceptible scion-rootstock combinations by two-dimensional gel electrophoresis (2DE). A total of 125 protein spots have been found to be differently accumulated and/or phosphorylated between the two rootstock combinations. Downregulation in tolerant plants upon CTV infection was detected for proteins involved in reactive oxygen species (ROS) scavenging and defense response, suggesting a probable acclimation response able to minimize the systemic effects of virus infection. Some of these proteins resulted to be modulated also in absence of virus infection, revealing a rootstock effect on scion proteome modulation. Moreover, the phospho-modulation of proteins involved in ROS scavenging and defense response, further supports their involvement either in scion-rootstock crosstalk or in the establishment of tolerance/susceptibility to CTV infection. PMID:26459956

  16. The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato.

    Science.gov (United States)

    Hage-Ahmed, Karin; Krammer, Johannes; Steinkellner, Siegrid

    2013-10-01

    Arbuscular mycorrhizal fungi (AMF) and their bioprotective aspects are of great interest in the context of sustainable agriculture. Combining the benefits of AMF with the utilisation of plant species diversity shows great promise for the management of plant diseases in environmentally compatible agriculture. In the present study, AMF were tested against Fusarium oxysporum f. sp. lycopersici with tomato intercropped with either leek, cucumber, basil, fennel or tomato itself. Arbuscular mycorrhizal (AM) root colonisation of tomato was clearly affected by its intercropping partners. Tomato intercropped with leek showed even a 20 % higher AM colonisation rate than tomato intercropped with tomato. Positive effects of AMF expressed as an increase of tomato biomass compared to the untreated control treatment could be observed in root as well as in shoot weights. A compensation of negative effects of F. oxysporum f. sp. lycopersici on tomato biomass by AMF was observed in the tomato/leek combination. The intercropping partners leek, cucumber, basil and tomato had no effect on F. oxysporum f. sp. lycopersici disease incidence or disease severity indicating no allelopathic suppression; however, tomato co-cultivated with tomato clearly showed a negative effect on one plant/pot with regard to biomass and disease severity of F. oxysporum f. sp. lycopersici. Nonetheless, bioprotective effects of AMF resulting in the decrease of F. oxysporum f. sp. lycopersici disease severity were evident in treatments with AMF and F. oxysporum f. sp. lycopersici co-inoculation. However, these bioprotective effects depended on the intercropping partner since these effects were only observed in the tomato/leek and tomato/basil combination and for the better developed plant of tomato/tomato. In conclusion, the effects of the intercropping partner on AMF colonisation of tomato are of great interest for crop plant communities and for the influences on each other. The outcome of the bioprotective

  17. Structure- and function-based design of Plasmodium-selective proteasome inhibitors.

    Science.gov (United States)

    Li, Hao; O'Donoghue, Anthony J; van der Linden, Wouter A; Xie, Stanley C; Yoo, Euna; Foe, Ian T; Tilley, Leann; Craik, Charles S; da Fonseca, Paula C A; Bogyo, Matthew

    2016-02-11

    The proteasome is a multi-component protease complex responsible for regulating key processes such as the cell cycle and antigen presentation. Compounds that target the proteasome are potentially valuable tools for the treatment of pathogens that depend on proteasome function for survival and replication. In particular, proteasome inhibitors have been shown to be toxic for the malaria parasite Plasmodium falciparum at all stages of its life cycle. Most compounds that have been tested against the parasite also inhibit the mammalian proteasome, resulting in toxicity that precludes their use as therapeutic agents. Therefore, better definition of the substrate specificity and structural properties of the Plasmodium proteasome could enable the development of compounds with sufficient selectivity to allow their use as anti-malarial agents. To accomplish this goal, here we use a substrate profiling method to uncover differences in the specificities of the human and P. falciparum proteasome. We design inhibitors based on amino-acid preferences specific to the parasite proteasome, and find that they preferentially inhibit the β2-subunit. We determine the structure of the P. falciparum 20S proteasome bound to the inhibitor using cryo-electron microscopy and single-particle analysis, to a resolution of 3.6 Å. These data reveal the unusually open P. falciparum β2 active site and provide valuable information about active-site architecture that can be used to further refine inhibitor design. Furthermore, consistent with the recent finding that the proteasome is important for stress pathways associated with resistance of artemisinin family anti-malarials, we observe growth inhibition synergism with low doses of this β2-selective inhibitor in artemisinin-sensitive and -resistant parasites. Finally, we demonstrate that a parasite-selective inhibitor could be used to attenuate parasite growth in vivo without appreciable toxicity to the host. Thus, the Plasmodium proteasome is a

  18. Enhanced proteasome degradation extends Caenorhabditis elegans lifespan and alleviates aggregation-related pathologies.

    Science.gov (United States)

    Chondrogianni, Niki; Georgila, Konstantina; Kourtis, Nikos; Tavernarakis, Nektarios; Gonos Efstathios, S

    2014-10-01

    Collapse of proteostasis and accumulation of damaged macromolecules have been recognized as hallmarks of aging and age-related diseases. The proteasome is the major cellular protease responsible for intracellular protein degradation, having an impaired function during aging. We have previously shown that proteasome activation through overexpression of β5 proteasome subunit delays replicative senescence and confers resistance to oxidative stress in primary fibroblasts. Herein, we have investigated the impact of enhanced proteasome function on organismal longevity and aggregation-related pathologies by employing Caenorhabditis elegans as a model system. We have found that overexpression of a core 20S proteasome subunit in wild type worms extends lifespan, healthspan and survival under proteotoxic conditions. The longevity prolonging effect of the proteasome subunit overexpression was found to depend on the FOXO transcription factor DAF-16 and was associated with its elevated transcriptional activity. We have also uncovered a major role of enhanced proteasome activity in aggregation-related pathologies underlying neurodegenerative diseases. Genetic activation of the proteasome minimized the detrimental effect of polyglutamine-induced toxicity mimicking Huntington's disease, whereas knock-down of the proteasome component exaggerated the disease phenotypes. Similar results were obtained by using a C.elegans model of Amyloid beta (Αβ) -induced toxicity mimicking Alzheimer's disease. Collectively, these findings demonstrate that enhanced proteasome function alleviates proteotoxicity and promotes longevity in synergy with other nodes of lifespan regulation in C.elegans. Understanding the mechanism by which preservation of proteostasis via enhancement of proteasome function, decelerates the aging process and alleviates age-related pathologies may assist in the rational design of therapeutic and anti-aging interventions. PMID:26461298

  19. Redox control of the ubiquitin-proteasome system

    DEFF Research Database (Denmark)

    Kriegenburg, Franziska; Poulsen, Esben G; Koch, Annett;

    2011-01-01

    is characteristic of many diseases and during aging. To counter the adverse effects of oxidative stress, cells can initiate an antioxidative response in an attempt to repair the damage, or rapidly channel the damaged proteins for degradation by the ubiquitin-proteasome system (UPS). Recent studies...... associated with a thioredoxin and other cofactors that may adjust the particle's response during an oxidative challenge. Here, we give an overview of the UPS and a detailed description of the degradation of oxidized proteins and of the crosstalk between oxidative stress and protein degradation in health and...

  20. FAT10, a Ubiquitin-Independent Signal for Proteasomal Degradation

    OpenAIRE

    Hipp, Mark Steffen; Kalveram, Birte; Raasi, Shahri; Groettrup, Marcus; Schmidtke, Gunter

    2005-01-01

    FAT10 is a small ubiquitin-like modifier that is encoded in the major histocompatibility complex and is synergistically inducible by tumor necrosis factor alpha and gamma interferon. It is composed of two ubiquitin-like domains and possesses a free C-terminal diglycine motif that is required for the formation of FAT10 conjugates. Here we show that unconjugated FAT10 and a FAT10 conjugate were rapidly degraded by the proteasome at a similar rate. Fusion of FAT10 to the N terminus of very long-...

  1. The ubiquitin proteasome system plays a role in venezuelan equine encephalitis virus infection.

    Directory of Open Access Journals (Sweden)

    Moushimi Amaya

    Full Text Available Many viruses have been implicated in utilizing or modulating the Ubiquitin Proteasome System (UPS to enhance viral multiplication and/or to sustain a persistent infection. The mosquito-borne Venezuelan equine encephalitis virus (VEEV belongs to the Togaviridae family and is an important biodefense pathogen and select agent. There are currently no approved vaccines or therapies for VEEV infections; therefore, it is imperative to identify novel targets for therapeutic development. We hypothesized that a functional UPS is required for efficient VEEV multiplication. We have shown that at non-toxic concentrations Bortezomib, a FDA-approved inhibitor of the proteasome, proved to be a potent inhibitor of VEEV multiplication in the human astrocytoma cell line U87MG. Bortezomib inhibited the virulent Trinidad donkey (TrD strain and the attenuated TC-83 strain of VEEV. Additional studies with virulent strains of Eastern equine encephalitis virus (EEEV and Western equine encephalitis virus (WEEV demonstrated that Bortezomib is a broad spectrum inhibitor of the New World alphaviruses. Time-of-addition assays showed that Bortezomib was an effective inhibitor of viral multiplication even when the drug was introduced many hours post exposure to the virus. Mass spectrometry analyses indicated that the VEEV capsid protein is ubiquitinated in infected cells, which was validated by confocal microscopy and immunoprecipitation assays. Subsequent studies revealed that capsid is ubiquitinated on K48 during early stages of infection which was affected by Bortezomib treatment. This study will aid future investigations in identifying host proteins as potential broad spectrum therapeutic targets for treating alphavirus infections.

  2. Cables1 controls p21/Cip1 protein stability by antagonizing proteasome subunit alpha type 3.

    Science.gov (United States)

    Shi, Z; Li, Z; Li, Z J; Cheng, K; Du, Y; Fu, H; Khuri, F R

    2015-05-01

    The cyclin-dependent kinase (CDK) inhibitor 1A, p21/Cip1, is a vital cell cycle regulator, dysregulation of which has been associated with a large number of human malignancies. One critical mechanism that controls p21 function is through its degradation, which allows the activation of its associated cell cycle-promoting kinases, CDK2 and CDK4. Thus delineating how p21 is stabilized and degraded will enhance our understanding of cell growth control and offer a basis for potential therapeutic interventions. Here we report a novel regulatory mechanism that controls the dynamic status of p21 through its interaction with Cdk5 and Abl enzyme substrate 1 (Cables1). Cables1 has a proposed role as a tumor suppressor. We found that upregulation of Cables1 protein was correlated with increased half-life of p21 protein, which was attributed to Cables1/p21 complex formation and supported by their co-localization in the nucleus. Mechanistically, Cables1 interferes with the proteasome (Prosome, Macropain) subunit alpha type 3 (PSMA3) binding to p21 and protects p21 from PSMA3-mediated proteasomal degradation. Moreover, silencing of p21 partially reverses the ability of Cables1 to induce cell death and inhibit cell proliferation. In further support of a potential pathophysiological role of Cables1, the expression level of Cables1 is tightly associated with p21 in both cancer cell lines and human lung cancer patient tumor samples. Together, these results suggest Cables1 as a novel p21 regulator through maintaining p21 stability and support the model that the tumor-suppressive function of Cables1 occurs at least in part through enhancing the tumor-suppressive activity of p21. PMID:24975575

  3. Secomycalolide A: A New Proteasome Inhibitor Isolated from a Marine Sponge of the Genus Mycale

    Directory of Open Access Journals (Sweden)

    Sachiko Tsukamoto

    2005-06-01

    Full Text Available A new oxazole-containing proteasome inhibitor, secomycalolide A, together with known mycalolide A and 30-hydroxymycalolide A, was isolated from a marine sponge of the genus Mycale. They showed proteasome inhibitory activities with IC50 values of 11-45 μg/mL.

  4. Structure of the Mycobacterium tuberculosis proteasome and mechanism of inhibition by a peptidyl boronate.

    Science.gov (United States)

    Hu, Guiqing; Lin, Gang; Wang, Ming; Dick, Lawrence; Xu, Rui-Ming; Nathan, Carl; Li, Huilin

    2006-03-01

    Mycobacterium tuberculosis (Mtb) has the remarkable ability to resist killing by human macrophages. The 750 kDa proteasome, not available in most eubacteria except Actinomycetes, appears to contribute to Mtb's resistance. The crystal structure of the Mtb proteasome at 3.0 A resolution reveals a substrate-binding pocket with composite features of the distinct beta1, beta2 and beta5 substrate binding sites of eukaryotic proteasomes, accounting for the broad specificity of the Mtb proteasome towards oligopeptides described in the companion article [Lin et al. (2006), Mol Microbiol doi:10.1111/j.1365-2958.2005.05035.x]. The substrate entrance at the end of the cylindrical proteasome appears open in the crystal structure due to partial disorder of the alpha-subunit N-terminal residues. However, cryo-electron microscopy of the core particle reveals a closed end, compatible with the density observed in negative-staining electron microscopy that depended on the presence of the N-terminal octapetides of the alpha-subunits in the companion article, suggesting that the Mtb proteasome has a gated structure. We determine for the first time the proteasomal inhibition mechanism of the dipeptidyl boronate N-(4-morpholine)carbonyl-beta-(1-naphthyl)-L-alanine-L-leucine boronic acid (MLN-273), an analogue of the antimyeloma drug bortezomib. The structure improves prospects for designing Mtb-specific proteasomal inhibitors as a novel approach to chemotherapy of tuberculosis. PMID:16468986

  5. Characterization of the proteasome from the extremely halophilic archaeon Haloarcula marismortui

    Directory of Open Access Journals (Sweden)

    B. Franzetti

    2002-01-01

    Full Text Available A 20S proteasome, comprising two subunits α and β, was purified from the extreme halophilic archaeon Haloarcula marismortui, which grows only in saturated salt conditions. The three-dimensional reconstruction of the H. marismortui proteasome (Hm proteasome, obtained from negatively stained electron micrographs, is virtually identical to the structure of a thermophilic proteasome filtered to the same resolution. The stability of the Hm proteasome was found to be less salt-dependent than that of other halophilic enzymes previously described. The proteolytic activity of the Hm proteasome was investigated using the malate dehydrogenase from H. marismortui (HmMalDH as a model substrate. The HmMalDH denatures when the salt concentration is decreased below 2 M. Under these conditions, the proteasome efficiently cleaves HmMalDH during its denaturation process, but the fully denatured HmMalDH is poorly degraded. These in vitro experiments show that, at low salt concentrations, the 20S proteasome from halophilic archaea eliminates a misfolded protein.

  6. Structure of the Mycobacterium tuberculosis proteasome and mechanism of inhibition by a peptidyl boronate

    Energy Technology Data Exchange (ETDEWEB)

    Hu,G.; Lin, G.; Wang, M.; Dick, L.; Xu, R.; Nathan, C.; Li, H.

    2006-01-01

    Mycobacterium tuberculosis (Mtb) has the remarkable ability to resist killing by human macrophages. The 750 kDa proteasome, not available in most eubacteria except Actinomycetes, appears to contribute to Mtb's resistance. The crystal structure of the Mtb proteasome at 3.0 Angstroms resolution reveals a substrate-binding pocket with composite features of the distinct {beta}1, {beta}2 and {beta}5 substrate binding sites of eukaryotic proteasomes, accounting for the broad specificity of the Mtb proteasome towards oligopeptides described in the companion article [Lin et al. (2006), Mol Microbiol doi:10.1111/j.1365-2958.2005.05035.x]. The substrate entrance at the end of the cylindrical proteasome appears open in the crystal structure due to partial disorder of the a-subunit N-terminal residues. However, cryo-electron microscopy of the core particle reveals a closed end, compatible with the density observed in negative-staining electron microscopy that depended on the presence of the N-terminal octapeptides of the a-subunits in the companion article, suggesting that the Mtb proteasome has a gated structure. We determine for the first time the proteasomal inhibition mechanism of the dipeptidyl boronate N-(4-morpholine)carbonyl-{beta}-(1-naphthyl)-l-alanine-l-leucine boronic acid (MLN-273), an analogue of the antimyeloma drug bortezomib. The structure improves prospects for designing Mtb-specific proteasomal inhibitors as a novel approach to chemotherapy of tuberculosis.

  7. Reciprocity in computer-human interaction: source-based, norm-based, and affect-based explanations.

    Science.gov (United States)

    Lee, Seungcheol Austin; Liang, Yuhua Jake

    2015-04-01

    Individuals often apply social rules when they interact with computers, and this is known as the Computers Are Social Actors (CASA) effect. Following previous work, one approach to understand the mechanism responsible for CASA is to utilize computer agents and have the agents attempt to gain human compliance (e.g., completing a pattern recognition task). The current study focuses on three key factors frequently cited to influence traditional notions of compliance: evaluations toward the source (competence and warmth), normative influence (reciprocity), and affective influence (mood). Structural equation modeling assessed the effects of these factors on human compliance with computer request. The final model shows that norm-based influence (reciprocity) increased the likelihood of compliance, while evaluations toward the computer agent did not significantly influence compliance. PMID:25803145

  8. Txl1 and Txc1 are co-factors of the 26S proteasome in fission yeast

    DEFF Research Database (Denmark)

    Andersen, Katrine M; Jensen, Camilla; Kriegenburg, Franziska;

    2011-01-01

    proteasomes. A txl1 null mutant, but not a txc1 null, displayed a synthetic growth defect with cut8, encoding a protein that tethers the proteasome to the nuclear membrane. Txc1 is present throughout the cytoplasm and nucleus, whereas Txl1 co-localizes with 26S proteasomes in both wild-type cells and in cut8...

  9. Temperature and resource availability may interactively affect over-wintering success of juvenile fish in a changing climate.

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    Jakob Brodersen

    Full Text Available The predicted global warming may affect freshwater systems at several organizational levels, from organism to ecosystem. Specifically, in temperate regions, the projected increase of winter temperatures may have important effects on the over-winter biology of a range of organisms and especially for fish and other ectothermic animals. However, temperature effects on organisms may be directed strongly by resource availability. Here, we investigated whether over-winter loss of biomass and lipid content of juvenile roach (Rutilus rutilus was affected by the physiologically relatively small (2-5 °C changes of winter temperatures predicted by the Intergovernmental Panel on Climate Change (IPCC, under both natural and experimental conditions. This was investigated in combination with the effects of food availability. Finally, we explored the potential for a correlation between lake temperature and resource levels for planktivorous fish, i.e., zooplankton biomass, during five consecutive winters in a south Swedish lake. We show that small increases in temperature (+2 °C affected fish biomass loss in both presence and absence of food, but negatively and positively respectively. Temperature alone explained only a minor part of the variation when food availability was not taken into account. In contrast to other studies, lipid analyses of experimental fish suggest that critical somatic condition rather than critical lipid content determined starvation induced mortality. Our results illustrate the importance of considering not only changes in temperature when predicting organism response to climate change but also food-web interactions, such as resource availability and predation. However, as exemplified by our finding that zooplankton over-winter biomass in the lake was not related to over-winter temperature, this may not be a straightforward task.

  10. Enhancing User Experience through Emotional Interaction: Determining Users' Interests in Online Art Collections Using AMARA (Affective Museum of Art Resource Agent)

    Science.gov (United States)

    Park, S. Joon

    2013-01-01

    The need for emotional interaction has already influenced various disciplines and industries, and online museums represent a domain where providing emotional interactions could have a significant impact. Today, online museums lack the appropriate affective and hedonic values necessary to engage art enthusiasts on an emotional level. To address…

  11. Puromycin induces SUMO and ubiquitin redistribution upon proteasome inhibition.

    Science.gov (United States)

    Matsumoto, Hotaru; Saitoh, Hisato

    2016-07-29

    We have previously reported the co-localization of O-propargyl-puromycin (OP-Puro) with SUMO-2/3 and ubiquitin at promyelocytic leukemia-nuclear bodies (PML-NBs) in the presence of the proteasome inhibitor MG132, implying a role for the ubiquitin family in sequestering OP-puromycylated immature polypeptides to the nucleus during impaired proteasome activity. Here, we found that as expected puromycin induced SUMO-1/2/3 accumulation with ubiquitin at multiple nuclear foci in HeLa cells when co-exposed to MG132. Co-administration of puromycin and MG132 also facilitated redistribution of PML and the SUMO-targeted ubiquitin ligase RNF4 concurrently with SUMO-2/3. As removal of the drugs from the medium led to disappearance of the SUMO-2/3-ubiquitin nuclear foci, our findings indicated that nuclear assembly/disassembly of SUMO-2/3 and ubiquitin was pharmacologically manipulable, supporting our previous observation on OP-Puro, which predicted the ubiquitin family function in sequestrating aberrant proteins to the nucleus. PMID:27181354

  12. Disease-proportional proteasomal degradation of missense dystrophins.

    Science.gov (United States)

    Talsness, Dana M; Belanto, Joseph J; Ervasti, James M

    2015-10-01

    The 427-kDa protein dystrophin is expressed in striated muscle where it physically links the interior of muscle fibers to the extracellular matrix. A range of mutations in the DMD gene encoding dystrophin lead to a severe muscular dystrophy known as Duchenne (DMD) or a typically milder form known as Becker (BMD). Patients with nonsense mutations in dystrophin are specifically targeted by stop codon read-through drugs, whereas out-of-frame deletions and insertions are targeted by exon-skipping therapies. Both treatment strategies are currently in clinical trials. Dystrophin missense mutations, however, cause a wide range of phenotypic severity in patients. The molecular and cellular consequences of such mutations are not well understood, and there are no therapies specifically targeting this genotype. Here, we have modeled two representative missense mutations, L54R and L172H, causing DMD and BMD, respectively, in full-length dystrophin. In vitro, the mutation associated with the mild phenotype (L172H) caused a minor decrease in tertiary stability, whereas the L54R mutation associated with a severe phenotype had a more dramatic effect. When stably expressed in mammalian muscle cells, the mutations caused steady-state decreases in dystrophin protein levels inversely proportional to the tertiary stability and directly caused by proteasomal degradation. Both proteasome inhibitors and heat shock activators were able to increase mutant dystrophin to WT levels, establishing the new cell lines as a platform to screen for potential therapeutics personalized to patients with destabilized dystrophin. PMID:26392559

  13. Identifying candidate genes affecting developmental time in Drosophila melanogaster: pervasive pleiotropy and gene-by-environment interaction

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    Hasson Esteban

    2008-08-01

    Full Text Available Abstract Background Understanding the genetic architecture of ecologically relevant adaptive traits requires the contribution of developmental and evolutionary biology. The time to reach the age of reproduction is a complex life history trait commonly known as developmental time. In particular, in holometabolous insects that occupy ephemeral habitats, like fruit flies, the impact of developmental time on fitness is further exaggerated. The present work is one of the first systematic studies of the genetic basis of developmental time, in which we also evaluate the impact of environmental variation on the expression of the trait. Results We analyzed 179 co-isogenic single P[GT1]-element insertion lines of Drosophila melanogaster to identify novel genes affecting developmental time in flies reared at 25°C. Sixty percent of the lines showed a heterochronic phenotype, suggesting that a large number of genes affect this trait. Mutant lines for the genes Merlin and Karl showed the most extreme phenotypes exhibiting a developmental time reduction and increase, respectively, of over 2 days and 4 days relative to the control (a co-isogenic P-element insertion free line. In addition, a subset of 42 lines selected at random from the initial set of 179 lines was screened at 17°C. Interestingly, the gene-by-environment interaction accounted for 52% of total phenotypic variance. Plastic reaction norms were found for a large number of developmental time candidate genes. Conclusion We identified components of several integrated time-dependent pathways affecting egg-to-adult developmental time in Drosophila. At the same time, we also show that many heterochronic phenotypes may arise from changes in genes involved in several developmental mechanisms that do not explicitly control the timing of specific events. We also demonstrate that many developmental time genes have pleiotropic effects on several adult traits and that the action of most of them is sensitive

  14. Prediction of a common structural scaffold for proteasome lid, COP9-signalosome and eIF3 complexes

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    Hofmann Kay

    2005-03-01

    Full Text Available Abstract Background The 'lid' subcomplex of the 26S proteasome and the COP9 signalosome (CSN complex share a common architecture consisting of six subunits harbouring a so-called PCI domain (proteasome, CSN, eIF3 at their C-terminus, plus two subunits containing MPN domains (Mpr1/Pad1 N-terminal. The translation initiation complex eIF3 also contains PCI- and MPN-domain proteins, but seems to deviate from the 6+2 stoichiometry. Initially, the PCI domain was defined as the region of detectable sequence similarity between the components mentioned above. Results During an exhaustive bioinformatical analysis of proteasome components, we detected multiple instances of tetratrico-peptide repeats (TPR in the N-terminal region of most PCI proteins, suggesting that their homology is not restricted to the PCI domain. We also detected a previously unrecognized PCI domain in the eIF3 component eIF3k, a protein whose 3D-structure has been determined recently. By using profile-guided alignment techniques, we show that the structural elements found in eIF3k are most likely conserved in all PCI proteins, resulting in a structural model for the canonical PCI domain. Conclusion Our model predicts that the homology domain PCI is not a true domain in the structural sense but rather consists of two subdomains: a C-terminal 'winged helix' domain with a key role in PCI:PCI interaction, preceded by a helical repeat region. The TPR-like repeats detected in the N-terminal region of PCI proteins most likely form an uninterrupted extension of the repeats found within the PCI domain boundaries. This model allows an interpretation of several puzzling experimental results.

  15. Melatonin-Induced Temporal Up-Regulation of Gene Expression Related to Ubiquitin/Proteasome System (UPS in the Human Malaria Parasite Plasmodium falciparum

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    Fernanda C. Koyama

    2014-12-01

    Full Text Available There is an increasing understanding that melatonin and the ubiquitin/ proteasome system (UPS interact to regulate multiple cellular functions. Post-translational modifications such as ubiquitination are important modulators of signaling processes, cell cycle and many other cellular functions. Previously, we reported a melatonin-induced upregulation of gene expression related to ubiquitin/proteasome system (UPS in Plasmodium falciparum, the human malaria parasite, and that P. falciparum protein kinase 7 influences this process. This implies a role of melatonin, an indolamine, in modulating intraerythrocytic development of the parasite. In this report we demonstrate by qPCR analysis, that melatonin induces gene upregulation in nine out of fourteen genes of the UPS, consisting of the same set of genes previously reported, between 4 to 5 h after melatonin treatment. We demonstrate that melatonin causes a temporally controlled gene expression of UPS members.

  16. Proteasome Inhibition Contributed to the Cytotoxicity of Arenobufagin after Its Binding with Na, K-ATPase in Human Cervical Carcinoma HeLa Cells.

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    Qingxi Yue

    Full Text Available Although the possibility of developing cardiac steroids/cardiac glycosides as novel cancer therapeutic agents has been recognized, the mechanism of their anticancer activity is still not clear enough. Toad venom extract containing bufadienolides, which belong to cardiac steroids, has actually long been used as traditional Chinese medicine in clinic for cancer therapy in China. The cytotoxicity of arenobufagin, a bufadienolide isolated from toad venom, on human cervical carcinoma HeLa cells was checked. And, the protein expression profile of control HeLa cells and HeLa cells treated with arenobufagin for 48 h was analyzed using two-dimensional electrophoresis, respectively. Differently expressed proteins in HeLa cells treated with arenobufagin were identified and the pathways related to these proteins were mapped from KEGG database. Computational molecular docking was performed to verify the binding of arenobufagin and Na, K-ATPase. The effects of arenobufagin on Na, K-ATPase activity and proteasome activity of HeLa cells were checked. The protein-protein interaction network between Na, K-ATPase and proteasome was constructed and the expression of possible intermediate proteins ataxin-1 and translationally-controlled tumor protein in HeLa cells treated with arenobufagin was then checked. Arenobufagin induced apoptosis and G2/M cell cycle arrest in HeLa cells. The cytotoxic effect of arenobufagin was associated with 25 differently expressed proteins including proteasome-related proteins, calcium ion binding-related proteins, oxidative stress-related proteins, metabolism-related enzymes and others. The results of computational molecular docking revealed that arenobufagin was bound in the cavity formed by the transmembrane alpha subunits of Na, K-ATPase, which blocked the pathway of extracellular Na+/K+ cation exchange and inhibited the function of ion exchange. Arenobufagin inhibited the activity of Na, K-ATPase and proteasome, decreased the

  17. Proteasome Inhibition Contributed to the Cytotoxicity of Arenobufagin after Its Binding with Na, K-ATPase in Human Cervical Carcinoma HeLa Cells.

    Science.gov (United States)

    Yue, Qingxi; Zhen, Hong; Huang, Ming; Zheng, Xi; Feng, Lixing; Jiang, Baohong; Yang, Min; Wu, Wanying; Liu, Xuan; Guo, Dean

    2016-01-01

    Although the possibility of developing cardiac steroids/cardiac glycosides as novel cancer therapeutic agents has been recognized, the mechanism of their anticancer activity is still not clear enough. Toad venom extract containing bufadienolides, which belong to cardiac steroids, has actually long been used as traditional Chinese medicine in clinic for cancer therapy in China. The cytotoxicity of arenobufagin, a bufadienolide isolated from toad venom, on human cervical carcinoma HeLa cells was checked. And, the protein expression profile of control HeLa cells and HeLa cells treated with arenobufagin for 48 h was analyzed using two-dimensional electrophoresis, respectively. Differently expressed proteins in HeLa cells treated with arenobufagin were identified and the pathways related to these proteins were mapped from KEGG database. Computational molecular docking was performed to verify the binding of arenobufagin and Na, K-ATPase. The effects of arenobufagin on Na, K-ATPase activity and proteasome activity of HeLa cells were checked. The protein-protein interaction network between Na, K-ATPase and proteasome was constructed and the expression of possible intermediate proteins ataxin-1 and translationally-controlled tumor protein in HeLa cells treated with arenobufagin was then checked. Arenobufagin induced apoptosis and G2/M cell cycle arrest in HeLa cells. The cytotoxic effect of arenobufagin was associated with 25 differently expressed proteins including proteasome-related proteins, calcium ion binding-related proteins, oxidative stress-related proteins, metabolism-related enzymes and others. The results of computational molecular docking revealed that arenobufagin was bound in the cavity formed by the transmembrane alpha subunits of Na, K-ATPase, which blocked the pathway of extracellular Na+/K+ cation exchange and inhibited the function of ion exchange. Arenobufagin inhibited the activity of Na, K-ATPase and proteasome, decreased the expression of Na, K

  18. Interactions between Bifidobacterium and Bacteroides species in cofermentations are affected by carbon sources, including exopolysaccharides produced by bifidobacteria.

    Science.gov (United States)

    Rios-Covian, David; Arboleya, Silvia; Hernandez-Barranco, Ana M; Alvarez-Buylla, Jorge R; Ruas-Madiedo, Patricia; Gueimonde, Miguel; de los Reyes-Gavilan, Clara G

    2013-12-01

    Cocultures of strains from two Bifidobacterium and two Bacteroides species were performed with exopolysaccharides (EPS) previously purified from bifidobacteria, with inulin, or with glucose as the carbon source. Bifidobacterium longum NB667 and Bifidobacterium breve IPLA20004 grew in glucose but showed poor or no growth in complex carbohydrates (inulin, EPS E44, and EPS R1), whereas Bacteroides grew well in the four carbon sources tested. In the presence of glucose, the growth of Bacteroides thetaiotaomicron DSM-2079 was inhibited by B. breve, whereas it remained unaffected in the presence of B. longum. Ba. fragilis DSM-2151 contributed to a greater survival of B. longum, promoting changes in the synthesis of short-chain fatty acids (SCFA) and organic acids in coculture with respect to monocultures. In complex carbohydrates, cocultures of bifidobacterium strains with Ba. thetaiotaomicron did not modify the behavior of Bacteroides nor improve the poor growth of bifidobacteria. The metabolic activity of Ba. fragilis in coculture with bifidobacteria was not affected by EPS, but greater survival of bifidobacteria at late stages of incubation occurred in cocultures than in monocultures, leading to a higher production of acetic acid than in monocultures. Therefore, cocultures of Bifidobacterium and Bacteroides can behave differently against fermentable carbohydrates as a function of the specific characteristics of the strains from each species. These results stress the importance of considering specific species and strain interactions and not simply higher taxonomic divisions in the relationship among intestinal microbial populations and their different responses to probiotics and prebiotics. PMID:24077708

  19. Legionella metaeffector exploits host proteasome to temporally regulate cognate effector.

    Directory of Open Access Journals (Sweden)

    Tomoko Kubori

    Full Text Available Pathogen-associated secretion systems translocate numerous effector proteins into eukaryotic host cells to coordinate cellular processes important for infection. Spatiotemporal regulation is therefore important for modulating distinct activities of effectors at different stages of infection. Here we provide the first evidence of "metaeffector," a designation for an effector protein that regulates the function of another effector within the host cell. Legionella LubX protein functions as an E3 ubiquitin ligase that hijacks the host proteasome to specifically target the bacterial effector protein SidH for degradation. Delayed delivery of LubX to the host cytoplasm leads to the shutdown of SidH within the host cells at later stages of infection. This demonstrates a sophisticated level of coevolution between eukaryotic cells and L. pneumophila involving an effector that functions as a key regulator to temporally coordinate the function of a cognate effector protein.

  20. Insights into the molecular architecture of the 26S proteasome.

    Science.gov (United States)

    Nickell, Stephan; Beck, Florian; Scheres, Sjors H W; Korinek, Andreas; Förster, Friedrich; Lasker, Keren; Mihalache, Oana; Sun, Na; Nagy, István; Sali, Andrej; Plitzko, Jürgen M; Carazo, Jose-Maria; Mann, Matthias; Baumeister, Wolfgang

    2009-07-21

    Cryo-electron microscopy in conjunction with advanced image analysis was used to analyze the structure of the 26S proteasome and to elucidate its variable features. We have been able to outline the boundaries of the ATPase module in the "base" part of the regulatory complex that can vary in its position and orientation relative to the 20S core particle. This variation is consistent with the "wobbling" model that was previously proposed to explain the role of the regulatory complex in opening the gate in the alpha-rings of the core particle. In addition, a variable mass near the mouth of the ATPase ring has been identified as Rpn10, a multiubiquitin receptor, by correlating the electron microscopy data with quantitative mass spectrometry.

  1. Proteasomal diseases are a new branch of autoinflammatory pathology

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    Evgeny Stanislavovich Fedorov

    2013-12-01

    Full Text Available The paper deals with a new autoinflammatory disease entity that is proteasomal diseases. The latter include three nosological entities: Nakajo–Nishimura syndrome (NNS, Japanese autoinflammatory syndrome with lipodystrophy; chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE syndrome; joint contractures, muscular atrophy, microcytic anemia, and panniculitisinduced lipodystrophy (JMP syndrome. All the three conditions are caused by mutations in one PSMB8 gene encoding the immunoproteasome subunit β5i. Unlike other autoinflammatory syndromes that are mainly IL-1-dependent, the leading component of the pathogenesis of these diseases is IL-6/γ−interferonі system hyperactivation. These diseases are characterized by childhoodonset, retarded physical development, different skin and muscular lesions, lipodystrophy, joint contractures, and hypochromic anemia, as well as elevated levels of acutephase markers; autoimmune disorders may joint in time.

  2. The ubiquitin-proteasome system in glioma cell cycle control

    Directory of Open Access Journals (Sweden)

    Vlachostergios Panagiotis J

    2012-07-01

    Full Text Available Abstract A major determinant of cell fate is regulation of cell cycle. Tight regulation of this process is lost during the course of development and progression of various tumors. The ubiquitin-proteasome system (UPS constitutes a universal protein degradation pathway, essential for the consistent recycling of a plethora of proteins with distinct structural and functional roles within the cell, including cell cycle regulation. High grade tumors, such as glioblastomas have an inherent potential of escaping cell cycle control mechanisms and are often refractory to conventional treatment. Here, we review the association of UPS with several UPS-targeted proteins and pathways involved in regulation of the cell cycle in malignant gliomas, and discuss the potential role of UPS inhibitors in reinstitution of cell cycle control.

  3. Proteasomal diseases are a new branch of autoinflammatory pathology

    Directory of Open Access Journals (Sweden)

    Evgeny Stanislavovich Fedorov

    2013-01-01

    Full Text Available The paper deals with a new autoinflammatory disease entity that is proteasomal diseases. The latter include three nosological entities: Nakajo–Nishimura syndrome (NNS, Japanese autoinflammatory syndrome with lipodystrophy; chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE syndrome; joint contractures, muscular atrophy, microcytic anemia, and panniculitisinduced lipodystrophy (JMP syndrome. All the three conditions are caused by mutations in one PSMB8 gene encoding the immunoproteasome subunit β5i. Unlike other autoinflammatory syndromes that are mainly IL-1-dependent, the leading component of the pathogenesis of these diseases is IL-6/γ−interferonі system hyperactivation. These diseases are characterized by childhoodonset, retarded physical development, different skin and muscular lesions, lipodystrophy, joint contractures, and hypochromic anemia, as well as elevated levels of acutephase markers; autoimmune disorders may joint in time.

  4. Preclinical evaluation of the proteasome inhibitor bortezomib in cancer therapy

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    Morgan Gareth

    2005-06-01

    Full Text Available Abstract Bortezomib is a highly selective, reversible inhibitor of the 26S proteasome that is indicated for single-agent use in the treatment of patients with multiple myeloma who have received at least 2 prior therapies and are progressing on their most recent therapy. Clinical investigations have been completed or are under way to evaluate the safety and efficacy of bortezomib alone or in combination with chemotherapy in multiple myeloma, both at relapse and presentation, as well as in other cancer types. The antiproliferative, proapoptotic, antiangiogenic, and antitumor activities of bortezomib result from proteasome inhibition and depend on the altered degradation of a host of regulatory proteins. Exposure to bortezomib has been shown to stabilize p21, p27, and p53, as well as the proapoptotic Bid and Bax proteins, caveolin-1, and inhibitor κB-α, which prevents activation of nuclear factor κB-induced cell survival pathways. Bortezomib also promoted the activation of the proapoptotic c-Jun-NH2 terminal kinase, as well as the endoplasmic reticulum stress response. The anticancer effects of bortezomib as a single agent have been demonstrated in xenograft models of multiple myeloma, adult T-cell leukemia, lung, breast, prostate, pancreatic, head and neck, and colon cancer, and in melanoma. In these preclinical in vivo studies, bortezomib treatment resulted in decreased tumor growth, angiogenesis, and metastasis, as well as increased survival and tumor apoptosis. In several in vitro and/or in vivo cancer models, bortezomib has also been shown to enhance the antitumor properties of several antineoplastic treatments. Importantly, bortezomib was generally well tolerated and did not appear to produce additive toxicities when combined with other therapies in the dosing regimens used in these preclinical in vivo investigations. These findings provide a rationale for further clinical trials using bortezomib alone or in combination regimens with

  5. Multi-scale interactions affecting transport, storage, and processing of solutes and sediments in stream corridors (Invited)

    Science.gov (United States)

    Harvey, J. W.; Packman, A. I.

    2010-12-01

    Surface water and groundwater flow interact with the channel geomorphology and sediments in ways that determine how material is transported, stored, and transformed in stream corridors. Solute and sediment transport affect important ecological processes such as carbon and nutrient dynamics and stream metabolism, processes that are fundamental to stream health and function. Many individual mechanisms of transport and storage of solute and sediment have been studied, including surface water exchange between the main channel and side pools, hyporheic flow through shallow and deep subsurface flow paths, and sediment transport during both baseflow and floods. A significant challenge arises from non-linear and scale-dependent transport resulting from natural, fractal fluvial topography and associated broad, multi-scale hydrologic interactions. Connections between processes and linkages across scales are not well understood, imposing significant limitations on system predictability. The whole-stream tracer experimental approach is popular because of the spatial averaging of heterogeneous processes; however the tracer results, implemented alone and analyzed using typical models, cannot usually predict transport beyond the very specific conditions of the experiment. Furthermore, the results of whole stream tracer experiments tend to be biased due to unavoidable limitations associated with sampling frequency, measurement sensitivity, and experiment duration. We recommend that whole-stream tracer additions be augmented with hydraulic and topographic measurements and also with additional tracer measurements made directly in storage zones. We present examples of measurements that encompass interactions across spatial and temporal scales and models that are transferable to a wide range of flow and geomorphic conditions. These results show how the competitive effects between the different forces driving hyporheic flow, operating at different spatial scales, creates a situation

  6. Amino acids and insulin act additively to regulate components of the ubiquitin-proteasome pathway in C2C12 myotubes

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    Lomax Michael A

    2007-03-01

    Full Text Available Abstract Background The ubiquitin-proteasome system is the predominant pathway for myofibrillar proteolysis but a previous study in C2C12 myotubes only observed alterations in lysosome-dependent proteolysis in response to complete starvation of amino acids or leucine from the media. Here, we determined the interaction between insulin and amino acids in the regulation of myotube proteolysis Results Incubation of C2C12 myotubes with 0.2 × physiological amino acids concentration (0.2 × PC AA, relative to 1.0 × PC AA, significantly increased total proteolysis and the expression of 14-kDa E2 ubiquitin conjugating enzyme (p Conclusion In a C2C12 myotube model of myofibrillar protein turnover, amino acid limitation increases proteolysis in a ubiquitin-proteasome-dependent manner. Increasing amino acids or leucine alone, act additively with insulin to down regulate proteolysis and expression of components of ubiquitin-proteasome pathway. The effects of amino acids on proteolysis but not insulin and leucine, are blocked by inhibition of the mTOR signalling pathway.

  7. Centrosomal localisation of the cancer/testis (CT) antigens NY-ESO-1 and MAGE-C1 is regulated by proteasome activity in tumour cells.

    Science.gov (United States)

    Pagotto, Anna; Caballero, Otavia L; Volkmar, Norbert; Devalle, Sylvie; Simpson, Andrew J G; Lu, Xin; Christianson, John C

    2013-01-01

    The Cancer/Testis (CT) antigen family of genes are transcriptionally repressed in most human tissues but are atypically re-expressed in many malignant tumour types. Their restricted expression profile makes CT antigens ideal targets for cancer immunotherapy. As little is known about whether CT antigens may be regulated by post-translational processing, we investigated the mechanisms governing degradation of NY-ESO-1 and MAGE-C1 in selected cancer cell lines. Inhibitors of proteasome-mediated degradation induced the partitioning of NY-ESO-1 and MAGE-C1 into a detergent insoluble fraction. Moreover, this treatment also resulted in increased localisation of NY-ESO-1 and MAGE-C1 at the centrosome. Despite their interaction, relocation of either NY-ESO-1 or MAGE-C1 to the centrosome could occur independently of each other. Using a series of truncated fragments, the regions corresponding to NY-ESO-1(91-150) and MAGE-C1(900-1116) were established as important for controlling both stability and localisation of these CT antigens. Our findings demonstrate that the steady state levels of NY-ESO-1 and MAGE-C1 are regulated by proteasomal degradation and that both behave as aggregation-prone proteins upon accumulation. With proteasome inhibitors being increasingly used as front-line treatment in cancer, these data raise issues about CT antigen processing for antigenic presentation and therefore immunogenicity in cancer patients.

  8. Human-Robot Interaction: Does Robotic Guidance Force Affect Gait-Related Brain Dynamics during Robot-Assisted Treadmill Walking?

    Science.gov (United States)

    Knaepen, Kristel; Mierau, Andreas; Swinnen, Eva; Fernandez Tellez, Helio; Michielsen, Marc; Kerckhofs, Eric; Lefeber, Dirk; Meeusen, Romain

    2015-01-01

    In order to determine optimal training parameters for robot-assisted treadmill walking, it is essential to understand how a robotic device interacts with its wearer, and thus, how parameter settings of the device affect locomotor control. The aim of this study was to assess the effect of different levels of guidance force during robot-assisted treadmill walking on cortical activity. Eighteen healthy subjects walked at 2 km.h-1 on a treadmill with and without assistance of the Lokomat robotic gait orthosis. Event-related spectral perturbations and changes in power spectral density were investigated during unassisted treadmill walking as well as during robot-assisted treadmill walking at 30%, 60% and 100% guidance force (with 0% body weight support). Clustering of independent components revealed three clusters of activity in the sensorimotor cortex during treadmill walking and robot-assisted treadmill walking in healthy subjects. These clusters demonstrated gait-related spectral modulations in the mu, beta and low gamma bands over the sensorimotor cortex related to specific phases of the gait cycle. Moreover, mu and beta rhythms were suppressed in the right primary sensory cortex during treadmill walking compared to robot-assisted treadmill walking with 100% guidance force, indicating significantly larger involvement of the sensorimotor area during treadmill walking compared to robot-assisted treadmill walking. Only marginal differences in the spectral power of the mu, beta and low gamma bands could be identified between robot-assisted treadmill walking with different levels of guidance force. From these results it can be concluded that a high level of guidance force (i.e., 100% guidance force) and thus a less active participation during locomotion should be avoided during robot-assisted treadmill walking. This will optimize the involvement of the sensorimotor cortex which is known to be crucial for motor learning.

  9. Human-Robot Interaction: Does Robotic Guidance Force Affect Gait-Related Brain Dynamics during Robot-Assisted Treadmill Walking?

    Directory of Open Access Journals (Sweden)

    Kristel Knaepen

    Full Text Available In order to determine optimal training parameters for robot-assisted treadmill walking, it is essential to understand how a robotic device interacts with its wearer, and thus, how parameter settings of the device affect locomotor control. The aim of this study was to assess the effect of different levels of guidance force during robot-assisted treadmill walking on cortical activity. Eighteen healthy subjects walked at 2 km.h-1 on a treadmill with and without assistance of the Lokomat robotic gait orthosis. Event-related spectral perturbations and changes in power spectral density were investigated during unassisted treadmill walking as well as during robot-assisted treadmill walking at 30%, 60% and 100% guidance force (with 0% body weight support. Clustering of independent components revealed three clusters of activity in the sensorimotor cortex during treadmill walking and robot-assisted treadmill walking in healthy subjects. These clusters demonstrated gait-related spectral modulations in the mu, beta and low gamma bands over the sensorimotor cortex related to specific phases of the gait cycle. Moreover, mu and beta rhythms were suppressed in the right primary sensory cortex during treadmill walking compared to robot-assisted treadmill walking with 100% guidance force, indicating significantly larger involvement of the sensorimotor area during treadmill walking compared to robot-assisted treadmill walking. Only marginal differences in the spectral power of the mu, beta and low gamma bands could be identified between robot-assisted treadmill walking with different levels of guidance force. From these results it can be concluded that a high level of guidance force (i.e., 100% guidance force and thus a less active participation during locomotion should be avoided during robot-assisted treadmill walking. This will optimize the involvement of the sensorimotor cortex which is known to be crucial for motor learning.

  10. Central 5-HT depletion enhances impulsive responding without affecting the accuracy of attentional performance: interactions with dopaminergic mechanisms.

    Science.gov (United States)

    Harrison, A A; Everitt, B J; Robbins, T W

    1997-10-01

    A series of ten experiments examined the effects of profound central 5-HT depletion on attentional performance in the rat in the five-choice serial reaction time task, and also determined the effects of such depletion on responding affected by d-amphetamine and by selective dopamine receptor antagonists. Rats were trained to detect and locate brief visual stimuli randomly presented in one of five spatial locations. When performance had stabilised (> 80% correct, choice serial reaction time task with the same degree of accuracy as the sham-operated controls. However, 5-HT depletion reduced the percentage of omitted trials and increased the number of premature/anticipatory responses. This pattern of behaviour following 5-HT depletion could not be attributed to enhanced primary motivation as demonstrated by measures of food intake and latencies to collect food reinforcement. The lesion attenuated the increase of premature responding induced by high doses of systemically administered d-amphetamine. 5-HT depletion also attenuated the dose-dependent decrease in accuracy induced by (-)-sulpiride, a D2 receptor antagonist, although the effects of this drug on response latencies and premature responding were similar in both groups. However, the systemic administration of the D1 receptor antagonist, SCH 23390, blocked the impulsive responding produced by the lesion as indicated by a lack of lesion effects on the percentage of omitted trials and premature responding. The results suggest that central 5-HT depletion results in impulsive, fast responding, which nevertheless does not impair accuracy of visual discrimination performance. The increased impulsivity may be mediated by altered 5-HT-dopamine interactions, with the lesion removing an inhibitory influence over dopamine neurotransmission. PMID:9372531

  11. Low-dose aspartame consumption differentially affects gut microbiota-host metabolic interactions in the diet-induced obese rat.

    Directory of Open Access Journals (Sweden)

    Marie S A Palmnäs

    Full Text Available Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat or high fat (HF, 60% kcal fat and further into ad libitum water control (W or low-dose aspartame (A, 5-7 mg/kg/d in drinking water treatments for 8 week (n = 10-12 animals/treatment. Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (P<0.05. Within HF, aspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation.

  12. Low-dose aspartame consumption differentially affects gut microbiota-host metabolic interactions in the diet-induced obese rat.

    Science.gov (United States)

    Palmnäs, Marie S A; Cowan, Theresa E; Bomhof, Marc R; Su, Juliet; Reimer, Raylene A; Vogel, Hans J; Hittel, Dustin S; Shearer, Jane

    2014-01-01

    Aspartame consumption is implicated in the development of obesity and metabolic disease despite the intention of limiting caloric intake. The mechanisms responsible for this association remain unclear, but may involve circulating metabolites and the gut microbiota. Aims were to examine the impact of chronic low-dose aspartame consumption on anthropometric, metabolic and microbial parameters in a diet-induced obese model. Male Sprague-Dawley rats were randomized into a standard chow diet (CH, 12% kcal fat) or high fat (HF, 60% kcal fat) and further into ad libitum water control (W) or low-dose aspartame (A, 5-7 mg/kg/d in drinking water) treatments for 8 week (n = 10-12 animals/treatment). Animals on aspartame consumed fewer calories, gained less weight and had a more favorable body composition when challenged with HF compared to animals consuming water. Despite this, aspartame elevated fasting glucose levels and an insulin tolerance test showed aspartame to impair insulin-stimulated glucose disposal in both CH and HF, independently of body composition. Fecal analysis of gut bacterial composition showed aspartame to increase total bacteria, the abundance of Enterobacteriaceae and Clostridium leptum. An interaction between HF and aspartame was also observed for Roseburia ssp wherein HF-A was higher than HF-W (Paspartame attenuated the typical HF-induced increase in the Firmicutes:Bacteroidetes ratio. Serum metabolomics analysis revealed aspartame to be rapidly metabolized and to be associated with elevations in the short chain fatty acid propionate, a bacterial end product and highly gluconeogenic substrate, potentially explaining its negative affects on insulin tolerance. How aspartame influences gut microbial composition and the implications of these changes on the development of metabolic disease require further investigation.

  13. The proteasome immunosubunits, PA28 and ER-aminopeptidase 1 protect melanoma cells from efficient MART-126-35 -specific T-cell recognition.

    Science.gov (United States)

    Keller, Martin; Ebstein, Frédéric; Bürger, Elke; Textoris-Taube, Kathrin; Gorny, Xenia; Urban, Sabrina; Zhao, Fang; Dannenberg, Tanja; Sucker, Antje; Keller, Christin; Saveanu, Loredana; Krüger, Elke; Rothkötter, Hermann-Josef; Dahlmann, Burkhardt; Henklein, Petra; Voigt, Antje; Kuckelkorn, Ulrike; Paschen, Annette; Kloetzel, Peter-Michael; Seifert, Ulrike

    2015-12-01

    The immunodominant MART-1(26(27)-35) epitope, liberated from the differentiation antigen melanoma antigen recognized by T cells/melanoma antigen A (MART-1/Melan-A), has been frequently targeted in melanoma immunotherapy, but with limited clinical success. Previous studies suggested that this is in part due to an insufficient peptide supply and epitope presentation, since proteasomes containing the immunosubunits β5i/LMP7 (LMP, low molecular weight protein) or β1i/LMP2 and β5i/LMP7 interfere with MART-1(26-35) epitope generation in tumor cells. Here, we demonstrate that in addition the IFN-γ-inducible proteasome subunit β2i/MECL-1 (multicatalytic endopeptidase complex-like 1), proteasome activator 28 (PA28), and ER-resident aminopeptidase 1 (ERAP1) impair MART-1(26-35) epitope generation. β2i/MECL-1 and PA28 negatively affect C- and N-terminal cleavage and therefore epitope liberation from the proteasome, whereas ERAP1 destroys the MART-1(26-35) epitope by overtrimming activity. Constitutive expression of PA28 and ERAP1 in melanoma cells indicate that both interfere with MART-1(26-35) epitope generation even in the absence of IFN-γ. In summary, our results provide first evidence that activities of different antigen-processing components contribute to an inefficient MART-1(26-35) epitope presentation, suggesting the tumor cell's proteolytic machinery might have an important impact on the outcome of epitope-specific immunotherapies. PMID:26399368

  14. Localization of the proteasomal ubiquitin receptors Rpn10 and Rpn13 by electron cryomicroscopy.

    Science.gov (United States)

    Sakata, Eri; Bohn, Stefan; Mihalache, Oana; Kiss, Petra; Beck, Florian; Nagy, Istvan; Nickell, Stephan; Tanaka, Keiji; Saeki, Yasushi; Förster, Friedrich; Baumeister, Wolfgang

    2012-01-31

    Two canonical subunits of the 26S proteasome, Rpn10 and Rpn13, function as ubiquitin (Ub) receptors. The mutual arrangement of these subunits--and all other non-ATPase subunits--in the regulatory particle is unknown. Using electron cryomicroscopy, we calculated difference maps between wild-type 26S proteasome from Saccharomyces cerevisiae and deletion mutants (rpn10Δ, rpn13Δ, and rpn10Δrpn13Δ). These maps allowed us to localize the two Ub receptors unambiguously. Rpn10 and Rpn13 mapped to the apical part of the 26S proteasome, above the N-terminal coiled coils of the AAA-ATPase heterodimers Rpt4/Rpt5 and Rpt1/Rpt2, respectively. On the basis of the mutual positions of Rpn10 and Rpn13, we propose a model for polyubiquitin binding to the 26S proteasome.

  15. Aggresome-like structure induced by isothiocyanates is novel proteasome-dependent degradation machinery

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Lixin, E-mail: lm293@georgetown.edu [Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057 (United States); Gan, Nanqin; Chung, Fung-Lung [Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057 (United States)

    2009-10-16

    Unwanted or misfolded proteins are either refolded by chaperones or degraded by the ubiquitin-proteasome system (UPS). When UPS is impaired, misfolded proteins form aggregates, which are transported along microtubules by motor protein dynein towards the juxta-nuclear microtubule-organizing center to form aggresome, a single cellular garbage disposal complex. Because aggresome formation results from proteasome failure, aggresome components are degraded through the autophagy/lysosome pathway. Here we report that small molecule isothiocyanates (ITCs) can induce formation of aggresome-like structure (ALS) through covalent modification of cytoplasmic {alpha}- and {beta}-tubulin. The formation of ALS is related to neither proteasome inhibition nor oxidative stress. ITC-induced ALS is a proteasome-dependent assembly for emergent removal of misfolded proteins, suggesting that the cell may have a previously unknown strategy to cope with misfolded proteins.

  16. Two-substrate association with the 20S proteasome at single-molecule level.

    Science.gov (United States)

    Hutschenreiter, Silke; Tinazli, Ali; Model, Kirstin; Tampé, Robert

    2004-07-01

    The bipartite structure of the proteasome raises the question of functional significance. A rational design for unraveling mechanistic details of the highly symmetrical degradation machinery from Thermoplasma acidophilum pursues orientated immobilization at metal-chelating interfaces via affinity tags fused either around the pore apertures or at the sides. End-on immobilization of the proteasome demonstrates that one pore is sufficient for substrate entry and product release. Remarkably, a 'dead-end' proteasome can process only one substrate at a time. In contrast, the side-on immobilized and free proteasome can bind two substrates, presumably one in each antechamber, with positive cooperativity as analyzed by surface plasmon resonance and single-molecule cross-correlation spectroscopy. Thus, the two-stroke engine offers the advantage of speeding up degradation without enhancing complexity.

  17. Novel internally quenched substrate of the trypsin-like subunit of 20S eukaryotic proteasome.

    Science.gov (United States)

    Gruba, Natalia; Wysocka, Magdalena; Brzezińska, Magdalena; Debowski, Dawid; Rolka, Krzysztof; Martin, Nathaniel I; Lesner, Adam

    2016-09-01

    This article describes the synthesis, using combinatorial chemistry, of internally quenched substrates of the trypsin-like subunit of human 20S proteasome. Such substrates were optimized in both the nonprime and prime regions of the peptide chain. Two were selected as the most susceptible for proteasomal proteolysis with excellent kinetic parameters: (i) ABZ-Val-Val-Ser-Arg-Ser-Leu-Gly-Tyr(3-NO2)-NH2 (kcat/KM = 934,000 M(-1) s(-1)) and (ii) ABZ-Val-Val-Ser-GNF-Ala-Met-Gly-Tyr(3-NO2)-NH2 (kcat/KM = 1,980,000 M(-1) s(-1)). Both compounds were efficiently hydrolyzed by the 20S proteasome at picomolar concentrations, demonstrating significant selectivity over other proteasome entities. PMID:26314791

  18. Secondary Metabolites Produced by an Endophytic Fungus Pestalotiopsis sydowiana and Their 20S Proteasome Inhibitory Activities.

    Science.gov (United States)

    Xia, Xuekui; Kim, Soonok; Liu, Changheng; Shim, Sang Hee

    2016-01-01

    Fungal endophytes have attracted attention due to their functional diversity. Secondary metabolites produced by Pestalotiopsis sydowiana from a halophyte, Phragmites communis Trinus, were investigated. Eleven compounds, including four penicillide derivatives (1-4) and seven α-pyrone analogues (5-10) were isolated from cultures of P. sydowiana. The compounds were identified based on spectroscopic data. The inhibitory activities against the 20S proteasome were evaluated. Compounds 1-3, 5, and 9-10 showed modest proteasome inhibition activities, while compound 8 showed strong activity with an IC50 of 1.2 ± 0.3 μM. This is the first study on the secondary metabolites produced by P. sydowiana and their proteasome inhibitory activities. The endophytic fungus P. sydowiana might be a good resource for proteasome inhibitors. PMID:27447600

  19. Proteasome inhibition as a new strategy in cancer therapy and chemoprevention 

    Directory of Open Access Journals (Sweden)

    Michał Maliński

    2013-02-01

    Full Text Available  The ubiquitin-proteasome system is one of the main pathways involved in degradation of cellular proteins and regulation of most biochemical processes critical for maintaining cellular homeostasis. Among proteins that undergo proteasomal degradation are those involved in signal transduction, metabolism regulation, cell cycle control and apoptosis. Therefore, inhibition of the ubiquitin-proteasome system causes inhibition of cell proliferation and induction of apoptosis, especially in cancer cells, which makes it a promising strategy of cancer therapy that is already supported by clinical trials. This article summarizes reports of known proteasome inhibitors, differing in chemical structure and mechanism of action, emphasizing their effects on intracellular phenomena related to apoptosis and cell cycle control.

  20. The ubiquitin proteasome system in glia and its role in neurodegenerative diseases

    NARCIS (Netherlands)

    Jansen, Anne H P; Reits, Eric A J; Hol, Elly M

    2014-01-01

    The ubiquitin proteasome system (UPS) is crucial for intracellular protein homeostasis and for degradation of aberrant and damaged proteins. The accumulation of ubiquitinated proteins is a hallmark of many neurodegenerative diseases, including amyotrophic lateral sclerosis, Alzheimer's, Parkinson's,

  1. Cooperation of multiple chaperones required for the assembly of mammalian 20S proteasomes

    DEFF Research Database (Denmark)

    Hirano, Y.; Hayashi, H.; Iemura, S.;

    2006-01-01

    The 20S proteasome is a catalytic core of the 26S proteasome, a central enzyme in the degradation of ubiquitin-conjugated proteins. It is composed of 14 distinct gene products that form four stacked rings of seven subunits each, a1-7ß1-7ß1-7a1-7. It is reported that the biogenesis of mammalian 20...

  2. Proteasome functioning in breast cancer: connection with clinical-pathological factors.

    Directory of Open Access Journals (Sweden)

    Elena E Shashova

    Full Text Available Breast cancer is one of four oncology diseases that are most widespread in the world. Moreover, breast cancer is one of leading causes of cancer-related deaths in female population within economically developed regions of the world. So far, detection of new mechanisms of breast cancer development is very important for discovery of novel areas in which therapy approaches may be elaborated. The objective of the present study is to investigate involvement of proteasomes, which cleave up to 90% of cellular proteins and regulate numerous cellular processes, in mechanisms of breast cancer development. Proteasome characteristics in 106 patient breast carcinomas and adjacent tissues, as well as relationships of detected proteasome parameters with clinical-pathological factors, were investigated. Proteasome chymotrypsin-like activity was evaluated by hydrolysis of fluorogenic peptide Suc-LLVY-AMC. The expression of proteasome subunits was studied by Western-blotting and immunohistochemistry. The wide range of chymotrypsin-like activity in tumors was detected. Activity in tumors was higher if compared to adjacent tissues in 76 from 106 patients. Multiple analysis of generalized linear models discovered that in estrogen α-receptor absence, tumor growth was connected with the enhanced expression of proteasome immune subunit LMP2 and proteasome activator PA700 in tumor (at 95% confidence interval. Besides, by this analysis we detected some phenomena in adjacent tissue, which are important for tumor growth and progression of lymph node metastasis in estrogen α-receptor absence. These phenomena are related to the enhanced expression of activator PA700 and immune subunit LMP7. Thus, breast cancer development is connected with functioning of immune proteasome forms and activator PA700 in patients without estrogen α-receptors in tumor cells. These results could indicate a field for search of new therapy approaches for this category of patients, which has the

  3. Molecular study on copper-mediated tumor proteasome inhibition and cell death.

    Science.gov (United States)

    Xiao, Yan; Chen, Di; Zhang, Xia; Cui, Qiuzhi; Fan, Yuhua; Bi, Caifeng; Dou, Q Ping

    2010-07-01

    The metal ion copper is a cofactor essential for maintaining normal biological and physical functions in human beings. High copper levels have been found in variety of tumor tissues and are involved in tumor angiogenesis processes. The ubiquitin-proteasome system plays an important role in cell growth and apoptosis and has been shown as a novel target for cancer therapy. We previously reported that some organic copper complexes can inhibit the proteasomal chymotrypsin-like activity and induce apoptosis in human cancer cells and xenograft models. In the current study, we investigated the effect of oxidation status of copper, Cu(I) or Cu(II), on inhibition of proteasome activity, induction of apoptosis, and induction of reactive oxygen species (ROS) in human cancer cells. We report four major findings here: i) both Cu(I) and Cu(II) could inhibit the chymotrypsin-like activity of purified 20S proteasome, but Cu(I) was more potent than Cu(II), ii) purified 20S proteasome protein was able to reduce Cu(II) to Cu(I), suggesting that Cu(I) is the oxidation status of copper that directly reacts with the proteasome, iii) when complexed with the copper ligand neocuproine, Cu(I) showed higher ability to induce ROS production in cancer cells, compared with Cu(II), iv) addition of a ROS scavenger in the cancer cell culture-blocked copper-induced ROS generation, but did not overcome copper-mediated proteasome-inhibitory and cell death-inducing events, demonstrating the ROS-independent proteasome-inhibitory property of copper complexes.

  4. ROS inhibitor N-acetyl-l-cysteine antagonizes the activity of proteasome inhibitors

    OpenAIRE

    Halasi, Marianna; Wang, Ming; Chavan, Tanmay S.; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L.

    2013-01-01

    NAC (N-acetyl-l-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H2O2. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabi...

  5. Validation of the 2nd Generation Proteasome Inhibitor Oprozomib for Local Therapy of Pulmonary Fibrosis.

    Directory of Open Access Journals (Sweden)

    Nora Semren

    Full Text Available Proteasome inhibition has been shown to prevent development of fibrosis in several organs including the lung. However, effects of proteasome inhibitors on lung fibrosis are controversial and cytotoxic side effects of the overall inhibition of proteasomal protein degradation cannot be excluded. Therefore, we hypothesized that local lung-specific application of a novel, selective proteasome inhibitor, oprozomib (OZ, provides antifibrotic effects without systemic toxicity in a mouse model of lung fibrosis. Oprozomib was first tested on the human alveolar epithelial cancer cell line A549 and in primary mouse alveolar epithelial type II cells regarding its cytotoxic effects on alveolar epithelial cells and compared to the FDA approved proteasome inhibitor bortezomib (BZ. OZ was less toxic than BZ and provided high selectivity for the chymotrypsin-like active site of the proteasome. In primary mouse lung fibroblasts, OZ showed significant anti-fibrotic effects, i.e. reduction of collagen I and α smooth muscle actin expression, in the absence of cytotoxicity. When applied locally into the lungs of healthy mice via instillation, OZ was well tolerated and effectively reduced proteasome activity in the lungs. In bleomycin challenged mice, however, locally applied OZ resulted in accelerated weight loss and increased mortality of treated mice. Further, OZ failed to reduce fibrosis in these mice. While upon systemic application OZ was well tolerated in healthy mice, it rather augmented instead of attenuated fibrotic remodelling of the lung in bleomycin challenged mice. To conclude, low toxicity and antifibrotic effects of OZ in pulmonary fibroblasts could not be confirmed for pulmonary fibrosis of bleomycin-treated mice. In light of these data, the use of proteasome inhibitors as therapeutic agents for the treatment of fibrotic lung diseases should thus be considered with caution.

  6. Reduced Levels of Proteasome Products in a Mouse Striatal Cell Model of Huntington's Disease.

    Directory of Open Access Journals (Sweden)

    Sayani Dasgupta

    Full Text Available Huntington's disease is the result of a long polyglutamine tract in the gene encoding huntingtin protein, which in turn causes a large number of cellular changes and ultimately results in neurodegeneration of striatal neurons. Although many theories have been proposed, the precise mechanism by which the polyglutamine expansion causes cellular changes is not certain. Some evidence supports the hypothesis that the long polyglutamine tract inhibits the proteasome, a multiprotein complex involved in protein degradation. However, other studies report normal proteasome function in cells expressing long polyglutamine tracts. The controversy may be due to the methods used to examine proteasome activity in each of the previous studies. In the present study, we measured proteasome function by examining levels of endogenous peptides that are products of proteasome cleavage. Peptide levels were compared among mouse striatal cell lines expressing either 7 glutamines (STHdhQ7/Q7 or 111 glutamines in the huntingtin protein, either heterozygous (STHdhQ7/Q111 or homozygous (STHdhQ111/Q111. Both of the cell lines expressing huntingtin with 111 glutamines showed a large reduction in nearly all of the peptides detected in the cells, relative to levels of these peptides in cells homozygous for 7 glutamines. Treatment of STHdhQ7/Q7 cells with proteasome inhibitors epoxomicin or bortezomib also caused a large reduction in most of these peptides, suggesting that they are products of proteasome-mediated cleavage of cellular proteins. Taken together, these results support the hypothesis that proteasome function is impaired by the expression of huntingtin protein containing long polyglutamine tracts.

  7. NAC1 regulates the recruitment of the proteasome complex into dendritic spines.

    Science.gov (United States)

    Shen, Haowei; Korutla, Laxminarayana; Champtiaux, Nicholas; Toda, Shigenobu; LaLumiere, Ryan; Vallone, Joseph; Klugmann, Matthias; Blendy, Julie A; Mackler, Scott A; Kalivas, Peter W

    2007-08-15

    Coordinated proteolysis of synaptic proteins is required for synaptic plasticity, but a mechanism for recruiting the ubiquitin-proteasome system (UPS) into dendritic spines is not known. NAC1 is a cocaine-regulated transcriptional protein that was found to complex with proteins in the UPS, including cullins and Mov34. NAC1 and the proteasome were cotranslocated from the nucleus into dendritic spines in cortical neurons in response to proteasome inhibition or disinhibiting synaptic activity with bicuculline. Bicuculline also produced a progressive accumulation of the proteasome and NAC1 in the postsynaptic density. Recruitment of the proteasome into dendrites and postsynaptic density by bicuculline was prevented in neurons from mice harboring an NAC1 gene deletion or in neurons transfected with mutated NAC1 lacking the proteasome binding domain. These experiments show that NAC1 modulates the translocation of the UPS from the nucleus into dendritic spines, thereby suggesting a potential missing link in the recruitment of necessary proteolysis machinery for synaptic remodeling.

  8. Downregulation of 26S proteasome catalytic activity promotes epithelial-mesenchymal transition

    Science.gov (United States)

    van Baarsel, Eric D.; Metz, Patrick J.; Fisch, Kathleen; Widjaja, Christella E.; Kim, Stephanie H.; Lopez, Justine; Chang, Aaron N.; Geurink, Paul P.; Florea, Bogdan I.; Overkleeft, Hermen S.; Ovaa, Huib; Bui, Jack D.; Yang, Jing; Chang, John T.

    2016-01-01

    The epithelial-mesenchymal transition (EMT) endows carcinoma cells with phenotypic plasticity that can facilitate the formation of cancer stem cells (CSCs) and contribute to the metastatic cascade. While there is substantial support for the role of EMT in driving cancer cell dissemination, less is known about the intracellular molecular mechanisms that govern formation of CSCs via EMT. Here we show that β2 and β5 proteasome subunit activity is downregulated during EMT in immortalized human mammary epithelial cells. Moreover, selective proteasome inhibition enabled mammary epithelial cells to acquire certain morphologic and functional characteristics reminiscent of cancer stem cells, including CD44 expression, self-renewal, and tumor formation. Transcriptomic analyses suggested that proteasome-inhibited cells share gene expression signatures with cells that have undergone EMT, in part, through modulation of the TGF-β signaling pathway. These findings suggest that selective downregulation of proteasome activity in mammary epithelial cells can initiate the EMT program and acquisition of a cancer stem cell-like phenotype. As proteasome inhibitors become increasingly used in cancer treatment, our findings highlight a potential risk of these therapeutic strategies and suggest a possible mechanism by which carcinoma cells may escape from proteasome inhibitor-based therapy. PMID:26930717

  9. The Proteasome Inhibitor Bortezomib Maintains Osteocyte Viability in Multiple Myeloma Patients by Reducing Both Apoptosis and Autophagy: A New Function for Proteasome Inhibitors.

    Science.gov (United States)

    Toscani, Denise; Palumbo, Carla; Dalla Palma, Benedetta; Ferretti, Marzia; Bolzoni, Marina; Marchica, Valentina; Sena, Paola; Martella, Eugenia; Mancini, Cristina; Ferri, Valentina; Costa, Federica; Accardi, Fabrizio; Craviotto, Luisa; Aversa, Franco; Giuliani, Nicola

    2016-04-01

    Multiple myeloma (MM) is characterized by severely imbalanced bone remodeling. In this study, we investigated the potential effect of proteasome inhibitors (PIs), a class of drugs known to stimulate bone formation, on the mechanisms involved in osteocyte death induced by MM cells. First, we performed a histological analysis of osteocyte viability on bone biopsies on a cohort of 37 MM patients with symptomatic disease. A significantly higher number of viable osteocytes was detected in patients treated with a bortezomib (BOR)-based regimen compared with those treated without BOR. Interestingly, both osteocyte autophagy and apoptosis were affected in vivo by BOR treatment. Thereafter, we checked the in vitro effect of BOR to understand the mechanisms whereby BOR maintains osteocyte viability in bone from MM patients. We found that osteocyte and preosteocyte autophagic death was triggered during coculturing with MM cells. Our evaluation was conducted by analyzing either autophagy markers microtubule-associated protein light chain 3 beta (LC3B) and SQSTM1/sequestome 1 (p62) levels, or the cell ultrastructure by transmission electron microscopy. PIs were found to increase the basal levels of LC3 expression in the osteocytes while blunting the myeloma-induced osteocyte death. PIs also reduced the autophagic death of osteocytes induced by high-dose dexamethasone (DEX) and potentiated the anabolic effect of PTH(1-34). Our data identify osteocyte autophagy as a new potential target in MM bone disease and support the use of PIs to maintain osteocyte viability and improve bone integrity in MM patients. PMID:26551485

  10. Proteasomal degradation of ubiquitinated proteins in oocyte meiosis and fertilization in mammals.

    Science.gov (United States)

    Karabinova, Pavla; Kubelka, Michal; Susor, Andrej

    2011-10-01

    Gametogenesis and fertilization are the key events in sexual reproduction. In the female, meiosis results in a large oocyte that is competent for fertilization and fundamental for the success of early embryonic development. Progression through meiosis is monitored by fine regulatory mechanisms. In this review, we focus on one of the most well-known regulatory elements, the E3 ligase APC/C, which mediates proteolytic degradation of a number of important substrates via the ubiquitin proteasome pathway (UPP). The UPP also indirectly regulates protein synthesis by affecting proteins involved in RNA metabolism, a process that is paramount for the transcriptionally silent oocyte. During the past few years, more evidence has accumulated to suggest that the UPP has an important role in zona pellucida penetration and gamete fusion in mammals. This review focuses on the function of the UPP in regulating oocyte meiotic maturation in mammals, with special attention to its role in chromosome segregation and polar body extrusion, its role in the acquisition of meiotic/developmental competence and recent advances in our understanding of the UPP role in fertilization.

  11. Pseudomonas syringae pv. syringae uses proteasome inhibitor syringolin A to colonize from wound infection sites.

    Directory of Open Access Journals (Sweden)

    Johana C Misas-Villamil

    2013-03-01

    Full Text Available Infection of plants by bacterial leaf pathogens at wound sites is common in nature. Plants defend wound sites to prevent pathogen invasion, but several pathogens can overcome spatial restriction and enter leaf tissues. The molecular mechanisms used by pathogens to suppress containment at wound infection sites are poorly understood. Here, we studied Pseudomonas syringae strains causing brown spot on bean and blossom blight on pear. These strains exist as epiphytes that can cause disease upon wounding caused by hail, sand storms and frost. We demonstrate that these strains overcome spatial restriction at wound sites by producing syringolin A (SylA, a small molecule proteasome inhibitor. Consequently, SylA-producing strains are able to escape from primary infection sites and colonize adjacent tissues along the vasculature. We found that SylA diffuses from the primary infection site and suppresses acquired resistance in adjacent tissues by blocking signaling by the stress hormone salicylic acid (SA. Thus, SylA diffusion creates a zone of SA-insensitive tissue that is prepared for subsequent colonization. In addition, SylA promotes bacterial motility and suppresses immune responses at the primary infection site. These local immune responses do not affect bacterial growth and were weak compared to effector-triggered immunity. Thus, SylA facilitates colonization from wounding sites by increasing bacterial motility and suppressing SA signaling in adjacent tissues.

  12. Protein degradation by ubiquitin–proteasome system in formation and labilization of contextual conditioning memory

    Science.gov (United States)

    Sol Fustiñana, María; de la Fuente, Verónica; Federman, Noel; Freudenthal, Ramiro

    2014-01-01

    The ubiquitin–proteasome system (UPS) of protein degradation has been evaluated in different forms of neural plasticity and memory. The role of UPS in such processes is controversial. Several results support the idea that the activation of this system in memory consolidation is necessary to overcome negative constrains for plasticity. In this case, the inhibition of the UPS during consolidation impairs memory. Similar results were reported for memory reconsolidation. However, in other cases, the inhibition of UPS had no effect on memory consolidation and reconsolidation but impedes the amnesic action of protein synthesis inhibition after retrieval. The last finding suggests a specific action of the UPS inhibitor on memory labilization. However, another interpretation is possible in terms of the synthesis/degradation balance of positive and negative elements in neural plasticity, as was found in the case of long-term potentiation. To evaluate these alternative interpretations, other reconsolidation-interfering drugs than translation inhibitors should be tested. Here we analyzed initially the UPS inhibitor effect in contextual conditioning in crabs. We found that UPS inhibition during consolidation impaired long-term memory. In contrast, UPS inhibition did not affect memory reconsolidation after contextual retrieval but, in fact, impeded memory labilization, blocking the action of drugs that does not affect directly the protein synthesis. To extend these finding to vertebrates, we performed similar experiments in contextual fear memory in mice. We found that the UPS inhibitor in hippocampus affected memory consolidation and blocked memory labilization after retrieval. These findings exclude alternative interpretations to the requirement of UPS in memory labilization and give evidence of this mechanism in both vertebrates and invertebrates. PMID:25135196

  13. NAC1, A POZ/BTB protein interacts with Parkin and may contribute to Parkinson's disease.

    Science.gov (United States)

    Korutla, L; Furlong, H A; Mackler, S A

    2014-01-17

    Loss-of-function in the Parkin protein is thought to play a part in causing neuronal cell death in patients with Parkinson's disease. This study explores the effect of Parkin degradation, via the overexpression of nucleus accumbens 1 (NAC1), on cell viability. It was found that NAC1 and Parkin are co-localized within the cell and interact with one another, leading to a decrease in Parkin levels. Moreover, NAC1 down-regulates Parkin by presenting it for ubiquitin-dependent proteasome degradation, which causes a decrease in proteasomal activity in neuronal cells. Consequently, this decrease in proteasomal activity leads to an increase in the cells' susceptibility to proteasome inhibition-induced toxicity. It was also found that Parkin and NAC1 are key proteins found to be present mainly in the cytoplasm and are co-localized in neurons of Parkinson's disease patients. Interestingly, mutation in the POZ/BTB domain (Q23L) of NAC1 disrupts the co-localization and interaction of NAC1 with Parkin and it further abrogates the proteasome inhibition-induced toxicity. We further observed that co-transfection of the mutant form of NAC1 with Parkin reversed the proteasome activity and 20S proteasome protein levels. These results indicate a novel interaction between NAC1 and Parkin that leads to neuronal cell death, a main characteristic in Parkinson's disease.

  14. Rapid Proteasomal Degradation of Mutant Proteins Is the Primary Mechanism Leading to Tumorigenesis in Patients With Missense AIP Mutations

    Science.gov (United States)

    Hernández-Ramírez, Laura C.; Martucci, Federico; Morgan, Rhodri M. L.; Trivellin, Giampaolo; Tilley, Daniel; Ramos-Guajardo, Nancy; Iacovazzo, Donato; D'Acquisto, Fulvio; Prodromou, Chrisostomos

    2016-01-01

    Context: The pathogenic effect of mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene (AIPmuts) in pituitary adenomas is incompletely understood. We have identified the primary mechanism of loss of function for missense AIPmuts. Objective: This study sought to analyze the mechanism/speed of protein turnover of wild-type and missense AIP variants, correlating protein half-life with clinical parameters. Design and Setting: Half-life and protein–protein interaction experiments and cross-sectional analysis of AIPmut positive patients' data were performed in a clinical academic research institution. Patients: Data were obtained from our cohort of pituitary adenoma patients and literature-reported cases. Interventions: Protein turnover of endogenous AIP in two cell lines and fifteen AIP variants overexpressed in HEK293 cells was analyzed via cycloheximide chase and proteasome inhibition. Glutathione-S-transferase pull-down and quantitative mass spectrometry identified proteins involved in AIP degradation; results were confirmed by coimmunoprecipitation and gene knockdown. Relevant clinical data was collected. Main Outcome Measures: Half-life of wild-type and mutant AIP proteins and its correlation with clinical parameters. Results: Endogenous AIP half-life was similar in HEK293 and lymphoblastoid cells (43.5 and 32.7 h). AIP variants were divided into stable proteins (median, 77.7 h; interquartile range [IQR], 60.7–92.9 h), and those with short (median, 27 h; IQR, 21.6–28.7 h) or very short (median, 7.7 h; IQR, 5.6–10.5 h) half-life; proteasomal inhibition rescued the rapid degradation of mutant proteins. The experimental half-life significantly correlated with age at diagnosis of acromegaly/gigantism (r = 0.411; P = .002). The FBXO3-containing SKP1–CUL1–F-box protein complex was identified as the E3 ubiquitin-ligase recognizing AIP. Conclusions: AIP is a stable protein, driven to ubiquitination by the SKP1–CUL1–F-box protein complex

  15. Novel proteasome inhibitor ixazomib sensitizes neuroblastoma cells to doxorubicin treatment

    Science.gov (United States)

    Li, Haoyu; Chen, Zhenghu; Hu, Ting; Wang, Long; Yu, Yang; Zhao, Yanling; Sun, Wenijing; Guan, Shan; Pang, Jonathan C.; Woodfield, Sarah E.; Liu, Qing; Yang, Jianhua

    2016-01-01

    Neuroblastoma (NB) is the most common extracranial malignant solid tumor seen in children and continues to lead to the death of many pediatric cancer patients. The poor outcome in high risk NB is largely attributed to the development of chemoresistant tumor cells. Doxorubicin (dox) has been widely employed as a potent anti-cancer agent in chemotherapeutic regimens; however, it also leads to chemoresistance in many cancer types including NB. Thus, developing novel small molecules that can overcome dox-induced chemoresistance is a promising strategy in cancer therapy. Here we show that the second generation proteasome inhibitor ixazomib (MLN9708) not only inhibits NB cell proliferation and induces apoptosis in vitro but also enhances dox-induced cytotoxicity in NB cells. Ixazomib inhibits dox-induced NF-κB activity and sensitizes NB cells to dox-induced apoptosis. More importantly, ixazomib demonstrated potent anti-tumor efficacy in vivo by enhancing dox-induced apoptosis in an orthotopic xenograft NB mouse model. Collectively, our study illustrates the anti-tumor efficacy of ixazomib in NB both alone and in combination with dox, suggesting that combination therapy including ixazomib with traditional therapeutic agents such as dox is a viable strategy that may achieve better outcomes for NB patients. PMID:27687684

  16. Association of Obesity with Proteasomal Gene Polymorphisms in Children

    Science.gov (United States)

    Kupca, Sarmite; Paramonova, Natalija; Sugoka, Olga; Rinkuza, Irena; Trapina, Ilva; Daugule, Ilva; Sipols, Alfred J.; Rumba-Rozenfelde, Ingrida

    2013-01-01

    The aim of this study was to ascertain possible associations between childhood obesity, its anthropometric and clinical parameters, and three loci of proteasomal genes rs2277460 (PSMA6 c.-110C>A), rs1048990 (PSMA6 c.-8C>G), and rs2348071 (PSMA3 c. 543+138G>A) implicated in obesity-related diseases. Obese subjects included 94 otherwise healthy children in Latvia. Loci were genotyped and then analyzed using polymerase chain reactions, with results compared to those of 191 nonobese controls. PSMA3 SNP frequency differences between obese children and controls, while not reaching significance, suggested a trend. These differences, however, proved highly significant (P G SNP differences, while being nonsignificant, likewise suggested a trend in comparison to the nonobese controls. No PSMA6 c.-110C>A SNP differences were detected in the obese group or its subsets. Finally, PSMA3 SNP differences were significantly associated (P < 0.05) with circulating low-density lipoprotein cholesterol (LDL) levels. Our results clearly implicate the PSMA3 gene locus as an obesity risk factor in those Latvian children with a family history of obesity. While being speculative, the clinical results are suggestive of altered circulatory LDL levels playing a possible role in the etiology of obesity in the young. PMID:24455213

  17. Association of Obesity with Proteasomal Gene Polymorphisms in Children

    Directory of Open Access Journals (Sweden)

    Sarmite Kupca

    2013-01-01

    Full Text Available The aim of this study was to ascertain possible associations between childhood obesity, its anthropometric and clinical parameters, and three loci of proteasomal genes rs2277460 (PSMA6 c.-110C>A, rs1048990 (PSMA6 c.-8C>G, and rs2348071 (PSMA3 c. 543+138G>A implicated in obesity-related diseases. Obese subjects included 94 otherwise healthy children in Latvia. Loci were genotyped and then analyzed using polymerase chain reactions, with results compared to those of 191 nonobese controls. PSMA3 SNP frequency differences between obese children and controls, while not reaching significance, suggested a trend. These differences, however, proved highly significant (PG SNP differences, while being nonsignificant, likewise suggested a trend in comparison to the nonobese controls. No PSMA6 c.-110C>A SNP differences were detected in the obese group or its subsets. Finally, PSMA3 SNP differences were significantly associated (P<0.05 with circulating low-density lipoprotein cholesterol (LDL levels. Our results clearly implicate the PSMA3 gene locus as an obesity risk factor in those Latvian children with a family history of obesity. While being speculative, the clinical results are suggestive of altered circulatory LDL levels playing a possible role in the etiology of obesity in the young.

  18. Different Degree in Proteasome Malfunction Has Various Effects on Root Growth Possibly through Preventing Cell Division and Promoting Autophagic Vacuolization

    OpenAIRE

    Xianyong Sheng; Qian Wei; Liping Jiang; Xue Li; Yuan Gao; Li Wang

    2012-01-01

    The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated protei...

  19. Combined inhibition of p97 and the proteasome causes lethal disruption of the secretory apparatus in multiple myeloma cells.

    Directory of Open Access Journals (Sweden)

    Holger W Auner

    Full Text Available Inhibition of the proteasome is a widely used strategy for treating multiple myeloma that takes advantage of the heavy secretory load that multiple myeloma cells (MMCs have to deal with. Resistance of MMCs to proteasome inhibition has been linked to incomplete disruption of proteasomal endoplasmic-reticulum (ER-associated degradation (ERAD and activation of non-proteasomal protein degradation pathways. The ATPase p97 (VCP/Cdc48 has key roles in mediating both ERAD and non-proteasomal protein degradation and can be targeted pharmacologically by small molecule inhibition. In this study, we compared the effects of p97 inhibition with Eeyarestatin 1 and DBeQ on the secretory apparatus of MMCs with the effects induced by the proteasome inhibitor bortezomib, and the effects caused by combined inhibition of p97 and the proteasome. We found that p97 inhibition elicits cellular responses that are different from those induced by proteasome inhibition, and that the responses differ considerably between MMC lines. Moreover, we found that dual inhibition of both p97 and the proteasome terminally disrupts ER configuration and intracellular protein metabolism in MMCs. Dual inhibition of p97 and the proteasome induced high levels of apoptosis in all of the MMC lines that we analysed, including bortezomib-adapted AMO-1 cells, and was also effective in killing primary MMCs. Only minor toxicity was observed in untransformed and non-secretory cells. Our observations highlight non-redundant roles of p97 and the proteasome in maintaining secretory homeostasis in MMCs and provide a preclinical conceptual framework for dual targeting of p97 and the proteasome as a potential new therapeutic strategy in multiple myeloma.

  20. CDK11{sup p58} represses vitamin D receptor-mediated transcriptional activation through promoting its ubiquitin-proteasome degradation

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Yayun; Hong, Yi; Zong, Hongliang; Wang, Yanlin; Zou, Weiying; Yang, Junwu; Kong, Xiangfei; Yun, Xiaojing [Gene Research Center, Shanghai Medical College and Institutes of Biomedical, Shanghai 200032 (China); Gu, Jianxin, E-mail: jxgu@shmu.edu.cn [Gene Research Center, Shanghai Medical College and Institutes of Biomedical, Shanghai 200032 (China)

    2009-08-28

    Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily and regulates transcription of target genes. In this study, we identified CDK11{sup p58} as a novel protein involved in the regulation of VDR. CDK11{sup p58}, a member of the large family of p34cdc2-related kinases, is associated with cell cycle progression, tumorigenesis, and apoptotic signaling. Our study demonstrated that CDK11{sup p58} interacted with VDR and repressed VDR-dependent transcriptional activation. Furthermore, overexpression of CDK11{sup p58} decreased the stability of VDR through promoting its ubiquitin-proteasome-mediated degradation. Taken together, these results suggest that CDK11{sup p58} is involved in the negative regulation of VDR.

  1. CDK11p58 represses vitamin D receptor-mediated transcriptional activation through promoting its ubiquitin-proteasome degradation

    International Nuclear Information System (INIS)

    Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily and regulates transcription of target genes. In this study, we identified CDK11p58 as a novel protein involved in the regulation of VDR. CDK11p58, a member of the large family of p34cdc2-related kinases, is associated with cell cycle progression, tumorigenesis, and apoptotic signaling. Our study demonstrated that CDK11p58 interacted with VDR and repressed VDR-dependent transcriptional activation. Furthermore, overexpression of CDK11p58 decreased the stability of VDR through promoting its ubiquitin-proteasome-mediated degradation. Taken together, these results suggest that CDK11p58 is involved in the negative regulation of VDR.

  2. N,C-Capped dipeptides with selectivity for mycobacterial proteasome over human proteasomes: role of S3 and S1 binding pockets.

    Science.gov (United States)

    Lin, Gang; Chidawanyika, Tamutenda; Tsu, Christopher; Warrier, Thulasi; Vaubourgeix, Julien; Blackburn, Christopher; Gigstad, Kenneth; Sintchak, Michael; Dick, Lawrence; Nathan, Carl

    2013-07-10

    We identified N,C-capped dipeptides that are selective for the Mycobacterium tuberculosis proteasome over human constitutive and immunoproteasomes. Differences in the S3 and S1 binding pockets appeared to account for the species selectivity. The inhibitors can penetrate mycobacteria and kill nonreplicating M. tuberculosis under nitrosative stress.

  3. 26S Proteasome regulation of Ankrd1/CARP in adult rat ventricular myocytes and human microvascular endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Samaras, Susan E. [Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN (United States); Chen, Billy [Molecular Medicine Program, Department of Medicine, Boston University School of Medicine, Boston, MA (United States); Koch, Stephen R. [Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN (United States); Sawyer, Douglas B.; Lim, Chee Chew [Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN (United States); Davidson, Jeffrey M., E-mail: jeff.davidson@vanderbilt.edu [Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN (United States); Research Service, Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN (United States)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer The 26S proteasome regulates Ankrd1 levels in cardiomyocytes and endothelial cells. Black-Right-Pointing-Pointer Ankrd1 protein degrades 60-fold faster in endothelial cells than cardiomyocytes. Black-Right-Pointing-Pointer Differential degradation appears related to nuclear vs. sarcolemmal localization. Black-Right-Pointing-Pointer Endothelial cell density shows uncoupling of Ankrd1 mRNA and protein levels. -- Abstract: Ankyrin repeat domain 1 protein (Ankrd1), also known as cardiac ankyrin repeat protein (CARP), increases dramatically after tissue injury, and its overexpression improves aspects of wound healing. Reports that Ankrd1/CARP protein stability may affect cardiovascular organization, together with our findings that the protein is crucial to stability of the cardiomyocyte sarcomere and increased in wound healing, led us to compare the contribution of Ankrd1/CARP stability to its abundance. We found that the 26S proteasome is the dominant regulator of Ankrd1/CARP degradation, and that Ankrd1/CARP half-life is significantly longer in cardiomyocytes (h) than endothelial cells (min). In addition, higher endothelial cell density decreased the abundance of the protein without affecting steady state mRNA levels. Taken together, our data and that of others indicate that Ankrd1/CARP is highly regulated at multiple levels of its expression. The striking difference in protein half-life between a muscle and a non-muscle cell type suggests that post-translational proteolysis is correlated with the predominantly structural versus regulatory role of the protein in the two cell types.

  4. Proteasome structure, function, and lessons learned from beta-lactone inhibitors.

    Science.gov (United States)

    Groll, Michael; Potts, Barbara C

    2011-12-01

    The 26S proteasome is the enzymatic core engine of the ubiquitin and proteasome dependent proteolytic system (UPS), the major eukaryotic pathway for regulated protein degradation. The UPS plays a pivotal role in cellular protein turnover, protein quality control, antigen processing, signal transduction, cell cycle regulation, cell differentiation and apoptosis, inspiring in-depth studies of proteasome structure and function and the search for selective inhibitors. Structural studies revealed that the 26S proteasome comprises up to two 19S regulatory caps flanking a cylindrical 20S core particle, which houses the proteolytic subunits and is present in all kingdoms of life. This review highlights current understanding of 20S architecture, maturation and assembly, the mechanism for selective degradation of protein substrates targeted for destruction, and relationships to other proteases. This knowledge base has benefited from structurally diverse proteasome inhibitors discovered from unique sources, including terrestrial and marine actinomycetes that produce the β-lactone-γ- lactam superfamily of inhibitors, including omuralide, salinosporamide A (marizomib; NPI-0052) and the cinnabaramides. These "minimalist inhibitors" utilize dense functionality to maximum efficiency for potent and selective proteasome inhibition and have advanced from biochemical tools to potential agrochemicals and anticancer agents. In this review, lessons learned from the β-lactone-γ-lactam superfamily are presented, with an emphasis on their unique binding mechanisms elucidated through structural biology in concert with medicinal chemistry. Distinctions between slowly reversible and irreversible inhibitors are discussed, together with the relationship of irreversible binding at the molecular level to prolonged duration proteasome inhibition in tumor cells, and in vitro and in vivo efficacy.

  5. Advancing the Strategic Messages Affecting Robot Trust Effect: The Dynamic of User- and Robot-Generated Content on Human-Robot Trust and Interaction Outcomes.

    Science.gov (United States)

    Liang, Yuhua Jake; Lee, Seungcheol Austin

    2016-09-01

    Human-robot interaction (HRI) will soon transform and shift the communication landscape such that people exchange messages with robots. However, successful HRI requires people to trust robots, and, in turn, the trust affects the interaction. Although prior research has examined the determinants of human-robot trust (HRT) during HRI, no research has examined the messages that people received before interacting with robots and their effect on HRT. We conceptualize these messages as SMART (Strategic Messages Affecting Robot Trust). Moreover, we posit that SMART can ultimately affect actual HRI outcomes (i.e., robot evaluations, robot credibility, participant mood) by affording the persuasive influences from user-generated content (UGC) on participatory Web sites. In Study 1, participants were assigned to one of two conditions (UGC/control) in an original experiment of HRT. Compared with the control (descriptive information only), results showed that UGC moderated the correlation between HRT and interaction outcomes in a positive direction (average Δr = +0.39) for robots as media and robots as tools. In Study 2, we explored the effect of robot-generated content but did not find similar moderation effects. These findings point to an important empirical potential to employ SMART in future robot deployment.

  6. Advancing the Strategic Messages Affecting Robot Trust Effect: The Dynamic of User- and Robot-Generated Content on Human-Robot Trust and Interaction Outcomes.

    Science.gov (United States)

    Liang, Yuhua Jake; Lee, Seungcheol Austin

    2016-09-01

    Human-robot interaction (HRI) will soon transform and shift the communication landscape such that people exchange messages with robots. However, successful HRI requires people to trust robots, and, in turn, the trust affects the interaction. Although prior research has examined the determinants of human-robot trust (HRT) during HRI, no research has examined the messages that people received before interacting with robots and their effect on HRT. We conceptualize these messages as SMART (Strategic Messages Affecting Robot Trust). Moreover, we posit that SMART can ultimately affect actual HRI outcomes (i.e., robot evaluations, robot credibility, participant mood) by affording the persuasive influences from user-generated content (UGC) on participatory Web sites. In Study 1, participants were assigned to one of two conditions (UGC/control) in an original experiment of HRT. Compared with the control (descriptive information only), results showed that UGC moderated the correlation between HRT and interaction outcomes in a positive direction (average Δr = +0.39) for robots as media and robots as tools. In Study 2, we explored the effect of robot-generated content but did not find similar moderation effects. These findings point to an important empirical potential to employ SMART in future robot deployment. PMID:27585068

  7. Voicing by adapting and innovating employees : An empirical study on how personality and environment interact to affect voice behavior

    NARCIS (Netherlands)

    Janssen, O; Cozijnsen, AJ

    1998-01-01

    This article reports two studies exploring how cognitive style preferences for adaption-innovation affect the likelihood that employees will voice ideas for organizational change toward their supervisors. As hypothesized, Study 1 demonstrates that innovatively compared to adaptively predisposed poli

  8. Plasma membrane lipid–protein interactions affect signaling processes in sterol-biosynthesis mutants in Arabidopsis thaliana

    OpenAIRE

    Zauber, Henrik; Burgos, Asdrubal; Garapati, Prashanth; Schulze, Waltraud X.

    2014-01-01

    The plasma membrane is an important organelle providing structure, signaling and transport as major biological functions. Being composed of lipids and proteins with different physicochemical properties, the biological functions of membranes depend on specific protein-protein and protein-lipid interactions. Interactions of proteins with their specific sterol and lipid environment were shown to be important factors for protein recruitment into sub-compartmental structures of the plasma membrane...

  9. How Attributes of the Feedback Message affect Subsequent Feedback Seeking: The interactive effects of feedback sign and type

    OpenAIRE

    Megan Medvedeff; Jane Brodie Gregory; Paul E Levy

    2008-01-01

    In the current study, we examined the interactive effects of feedback type and sign on feedback-seeking behaviour, as well as the moderating role of regulatory focus. Using a behavioural measure of feedback seeking, we demonstrated a strong interaction between feedback type and sign, such that individuals subsequently sought the most feedback after they were provided with negative process feedback. Additionally, results suggested that an individual's chronic regulatory focus has implications ...

  10. How the Use of Second Life Affects E-Learners' Perceptions of Social Interaction in Online Courses

    Directory of Open Access Journals (Sweden)

    Carolyn Rude-Parkins

    2009-04-01

    Full Text Available Educators, researchers, and online courses designers are increasingly investigating the use of 3-D shared virtual worlds for online education. This paper discusses the importance of social interaction in e-learning. We present the idea of using Second Life, a 3-D shared virtual world, in online courses. The researchers investigated the impact of using Second Life as a learning environment and a communication medium in online courses. We measured the extent to which the completion of a learning task and the communication in Second Life can enhance the elearners' perceptions of social interaction via a self-report questionnaire. A prototype application called The Village of Belknap was developed by the Delphi Center of Teaching and Learning at the University of Louisville. The study compared the perception of social interaction of e-learners who participated in Second Life sessions with the perception of social interaction of e-learners who did not participate in the Second Life sessions. The results indicated that the use of Second Life has a positive impact on experiencing a high perception of social interaction in online courses.

  11. Proteasome inhibition improves the muscle of laminin α2 chain-deficient mice.

    Science.gov (United States)

    Carmignac, Virginie; Quéré, Ronan; Durbeej, Madeleine

    2011-02-01

    Muscle atrophy, a significant characteristic of congenital muscular dystrophy with laminin α2 chain deficiency (also known as MDC1A), occurs by a change in the normal balance between protein synthesis and protein degradation. The ubiquitin-proteasome system (UPS) plays a key role in protein degradation in skeletal muscle cells. In order to identify new targets for drug therapy against MDC1A, we have investigated whether increased proteasomal degradation is a feature of MDC1A. Using the generated dy(3K)/dy(3K) mutant mouse model of MDC1A, we studied the expression of members of the ubiquitin-proteasome pathway in laminin α2 chain-deficient muscle, and we treated dy(3K)/dy(3K) mice with the proteasome inhibitor MG-132. We show that members of the UPS are upregulated and that the global ubiquitination of proteins is raised in dystrophic limb muscles. Also, phosphorylation of Akt is diminished in diseased muscles. Importantly, proteasome inhibition significantly improves the dystrophic dy(3K)/dy(3K) phenotype. Specifically, treatment with MG-132 increases lifespan, enhances locomotive activity, enlarges muscle fiber diameter, reduces fibrosis, restores Akt phosphorylation and decreases apoptosis. These studies promote better understanding of the disease process in mice and could lead to a drug therapy for MDC1A patients.

  12. Proteasome inhibitors attenuated cholesterol-induced cardiac hypertrophy in H9c2 cells

    Science.gov (United States)

    Lee, Hyunjung; Park, Jinyoung; Kim, Eunice EunKyeong; Yoo, Young Sook; Song, Eun Joo

    2016-01-01

    The Ubiquitin proteasome system (UPS) plays roles in protein degradation, cell cycle control, and growth and inflammatory cell signaling. Dysfunction of UPS in cardiac diseases has been seen in many studies. Cholesterol acts as an inducer of cardiac hypertrophy. In this study, the effect of proteasome inhibitors on the cholesterol-induced hypertrophic growth in H9c2 cells is examined in order to observe whether UPS is involved in cardiac hypertrophy. The treatment of proteasome inhibitors MG132 and Bortezomib markedly reduced cellular surface area and mRNA expression of β-MHC in cholesterol-induced cardiac hypertrophy. In addition, activated AKT and ERK were significantly attenuated by MG132 and Bortezomib in cholesterol-induced cardiac hypertrophy. We demonstrated that cholesterol-induced cardiac hypertrophy was suppressed by proteasome inhibitors. Thus, regulatory mechanism of cholesterol-induced cardiac hypertrophy by proteasome inhibitors may provide a new therapeutic strategy to prevent the progression of heart failure. [BMB Reports 2016; 49(5): 270-275] PMID:26592933

  13. Identification of a new series of amides as non-covalent proteasome inhibitors.

    Science.gov (United States)

    Scarbaci, Kety; Troiano, Valeria; Micale, Nicola; Ettari, Roberta; Tamborini, Lucia; Di Giovanni, Carmen; Cerchia, Carmen; Grasso, Silvana; Novellino, Ettore; Schirmeister, Tanja; Lavecchia, Antonio; Zappalà, Maria

    2014-04-01

    Proteasome inhibition has emerged as an important therapeutic strategy for the treatment of multiple myeloma (MM) and some forms of lymphoma, with potential application in other types of cancers. 20S proteasome consists of three different catalytic activities known as chymotrypsin-like (ChT-L), trypsin-like (T-L), and, post-glutamyl peptide hydrolyzing (PGPH) or caspase-like (C-L), which are located respectively on the β5, β2, and β1 subunits of each heptameric β rings. Currently a wide number of covalent proteasome inhibitors are reported in literature; however, the less widely investigated non-covalent inhibitors might be a promising alternative to employ in therapy, because of the lack of all drawbacks and side-effects related to irreversible inhibition. In the present work we identified a series of amides, two of which (1b and 1f) are good candidates to non-covalent inhibition of the chymotrypsin-like activity of the β5 proteasome subunit. The non-covalent binding mode was corroborated by docking simulations of the most active inhibitors 1b, 1f and 2h into the yeast 20S proteasome crystal structure. PMID:24561716

  14. A Set of Activity-Based Probes to Visualize Human (Immuno)proteasome Activities.

    Science.gov (United States)

    de Bruin, Gerjan; Xin, Bo Tao; Kraus, Marianne; van der Stelt, Mario; van der Marel, Gijsbert A; Kisselev, Alexei F; Driessen, Christoph; Florea, Bogdan I; Overkleeft, Herman S

    2016-03-18

    Proteasomes are therapeutic targets for various cancers and autoimmune diseases. Constitutively expressed proteasomes have three active sites, β1c, β2c, and β5c. Lymphoid tissues also express the immunoproteasome subunits β1i, β2i, and β5i. Rapid and simultaneous measurement of the activity of these catalytic subunits would assist in the discovery of new inhibitors, improve analysis of proteasome inhibitors in clinical trials, and simplify analysis of subunit expression. In this work, we present a cocktail of activity-based probes that enables simultaneous gel-based detection of all six catalytic human proteasome subunits. We used this cocktail to develop specific inhibitors for β1c, β2c, β5c, and β2i, to compare the active-site specificity of clinical proteasome inhibitors, and to demonstrate that many hematologic malignancies predominantly express immunoproteasomes. Furthermore, we show that selective and complete inhibition of β5i and β1i is cytotoxic to primary cells from acute lymphocytic leukemia (ALL) patients. PMID:26511210

  15. Repression of protein translation and mTOR signaling by proteasome inhibitor in colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, William Ka Kei, E-mail: wukakei@cuhk.edu.hk [Institute of Digestive Diseases, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Volta, Viviana [Molecular Histology and Cellular Growth Unit, DiBiT-San Raffaele Scientific Institute (Italy); Dipartimento di Scienze dell' Ambiente e della Vita (DiSAV), University of Eastern Piedmont (Italy); Cho, Chi Hin, E-mail: chcho@cuhk.edu.hk [Institute of Digestive Diseases, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Wu, Ya Chun; Li, Hai Tao [Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Yu, Le [Institute of Digestive Diseases, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Li, Zhi Jie [Department of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Sung, Joseph Jao Yiu, E-mail: joesung@cuhk.edu.hk [Institute of Digestive Diseases, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong); Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong (Hong Kong)

    2009-09-04

    Protein homeostasis relies on a balance between protein synthesis and protein degradation. The ubiquitin-proteasome system is a major catabolic pathway for protein degradation. In this respect, proteasome inhibition has been used therapeutically for the treatment of cancer. Whether inhibition of protein degradation by proteasome inhibitor can repress protein translation via a negative feedback mechanism, however, is unknown. In this study, proteasome inhibitor MG-132 lowered the proliferation of colon cancer cells HT-29 and SW1116. In this connection, MG-132 reduced the phosphorylation of mammalian target of rapamycin (mTOR) at Ser2448 and Ser2481 and the phosphorylation of its downstream targets 4E-BP1 and p70/p85 S6 kinases. Further analysis revealed that MG-132 inhibited protein translation as evidenced by the reductions of {sup 35}S-methionine incorporation and polysomes/80S ratio. Knockdown of raptor, a structural component of mTOR complex 1, mimicked the anti-proliferative effect of MG-132. To conclude, we demonstrate that the inhibition of protein degradation by proteasome inhibitor represses mTOR signaling and protein translation in colon cancer cells.

  16. Mitochondrial Malfunctioning, Proteasome Arrest and Apoptosis in Cancer Cells by Focused Intracellular Generation of Oxygen Radicals

    Directory of Open Access Journals (Sweden)

    Ilaria Postiglione

    2015-08-01

    Full Text Available Photofrin/photodynamic therapy (PDT at sub-lethal doses induced a transient stall in proteasome activity in surviving A549 (p53+/+ and H1299 (p53−/− cells as indicated by the time-dependent decline/recovery of chymotrypsin-like activity. Indeed, within 3 h of incubation, Photofrin invaded the cytoplasm and localized preferentially within the mitochondria. Its light activation determined a decrease in mitochondrial membrane potential and a reversible arrest in proteasomal activity. A similar result is obtained by treating cells with Antimycin and Rotenone, indicating, as a common denominator of this effect, the ATP decrease. Both inhibitors, however, were more toxic to cells as the recovery of proteasomal activity was incomplete. We evaluated whether combining PDT (which is a treatment for killing tumor cells, per se, and inducing proteasome arrest in the surviving ones with Bortezomib doses capable of sustaining the stall would protract the arrest with sufficient time to induce apoptosis in remaining cells. The evaluation of the mitochondrial membrane depolarization, residual proteasome and mitochondrial enzymatic activities, colony-forming capabilities, and changes in protein expression profiles in A549 and H1299 cells under a combined therapeutic regimen gave results consistent with our hypothesis.

  17. USP14 deubiquitinates proteasome-bound substrates that are ubiquitinated at multiple sites.

    Science.gov (United States)

    Lee, Byung-Hoon; Lu, Ying; Prado, Miguel A; Shi, Yuan; Tian, Geng; Sun, Shuangwu; Elsasser, Suzanne; Gygi, Steven P; King, Randall W; Finley, Daniel

    2016-04-21

    USP14 is a major regulator of the proteasome and one of three proteasome-associated deubiquitinating enzymes. Its effects on protein turnover are substrate-specific, for unknown reasons. We report that USP14 shows a marked preference for ubiquitin-cyclin B conjugates that carry more than one ubiquitin modification or chain. This specificity is conserved from yeast to humans and is independent of chain linkage type. USP14 has been thought to cleave single ubiquitin groups from the distal tip of a chain, but we find that it removes chains from cyclin B en bloc, proceeding until a single chain remains. The suppression of degradation by USP14's catalytic activity reflects its capacity to act on a millisecond time scale, before the proteasome can initiate degradation of the substrate. In addition, single-molecule studies showed that the dwell time of ubiquitin conjugates at the proteasome was reduced by USP14-dependent deubiquitination. In summary, the specificity of the proteasome can be regulated by rapid ubiquitin chain removal, which resolves substrates based on a novel aspect of ubiquitin conjugate architecture. PMID:27074503

  18. Melittin restores proteasome function in an animal model of ALS

    Directory of Open Access Journals (Sweden)

    Lee Sang Min

    2011-06-01

    Full Text Available Abstract Amyotrophic lateral sclerosis (ALS is a paralyzing disorder characterized by the progressive degeneration and death of motor neurons and occurs both as a sporadic and familial disease. Mutant SOD1 (mtSOD1 in motor neurons induces vulnerability to the disease through protein misfolding, mitochondrial dysfunction, oxidative damage, cytoskeletal abnormalities, defective axonal transport- and growth factor signaling, excitotoxicity, and neuro-inflammation. Melittin is a 26 amino acid protein and is one of the components of bee venom which is used in traditional Chinese medicine to inhibit of cancer cell proliferation and is known to have anti-inflammatory and anti-arthritic effects. The purpose of the present study was to determine if melittin could suppress motor neuron loss and protein misfolding in the hSOD1G93A mouse, which is commonly used as a model for inherited ALS. Meltittin was injected at the 'ZuSanLi' (ST36 acupuncture point in the hSOD1G93A animal model. Melittin-treated animals showed a decrease in the number of microglia and in the expression level of phospho-p38 in the spinal cord and brainstem. Interestingly, melittin treatment in symptomatic ALS animals improved motor function and reduced the level of neuron death in the spinal cord when compared to the control group. Furthermore, we found increased of α-synuclein modifications, such as phosphorylation or nitration, in both the brainstem and spinal cord in hSOD1G93A mice. However, melittin treatment reduced α-synuclein misfolding and restored the proteasomal activity in the brainstem and spinal cord of symptomatic hSOD1G93A transgenic mice. Our research suggests a potential functional link between melittin and the inhibition of neuroinflammation in an ALS animal model.

  19. The Ubiquitin-Proteasome System and Microvascular Complications of Diabetes

    Directory of Open Access Journals (Sweden)

    Saeed Yadranji Aghdam

    2013-01-01

    Full Text Available The ubiquitin-proteasome system (UPS is the mainstay of protein quality control which regulates cell cycle, differentiation and various signal transduction pathways in eukaryotic cells. The timely and selective degradation of surplus and/or aberrant proteins by the UPS is essential for normal cellular physiology. Any disturbance, delay or exaggeration in the process of selection, sequestration, labeling for degradation and degradation of target proteins by the UPS will compromise cellular and tissue homeostasis. High blood glucose or hyperglycemia caused by diabetes disrupts normal vascular function in several target organs including the retina and kidney resulting in the development of diabetic retinopathy (DR and diabetic nephropathy (DN. We and others have shown that hyperglycemia and oxidative stress modulate UPS activity in the retina and kidney. The majority of studies have focused on the kidney and provided insights into the contribution of dysregulated UPS to microvascular damage in DN. The eye is a unique organ in which a semi-fluid medium, the vitreous humor, separates the neural retina and its anastomosed blood vessels from the semi-solid lens tissue. The complexity of the cellular and molecular components of the eye may require a normal functioning and well tuned UPS for healthy vision. Altered UPS activity may contribute to the development of retinal microvascular complications of diabetes. A better understanding of the molecular nature of the ocular UPS function under normal and diabetic conditions is essential for development of novel strategies targeting its activity. This review will discuss the association of retinal vascular cell UPS activity with microvascular damage in DR with emphasis on alterations of the PA28 subunits of the UPS.

  20. The structure of flower visitation webs : how morphology and abundance affect interaction patterns between flowers and flower visitors

    NARCIS (Netherlands)

    Stang, Martina

    2007-01-01

    Interaction patterns between plants and flower visitors in a Mediterranean flower visitation web can be explained surprisingly well by the combination of two simple mechanisms. Firstly, the size threshold that the nectar tube depth of flowers puts on the tongue length of potential flower visitors; a

  1. An Empirical Study of Factors Affecting Mobile Wireless Technology Adoption for Promoting Interactive Lectures in Higher Education

    Science.gov (United States)

    Gan, Chin Lay; Balakrishnan, Vimala

    2016-01-01

    Use of mobile technology is widespread, particularly among the younger generation. There is a huge potential for utilizing such technology in lecture classes with large numbers of students, serving as an interaction tool between the students and lecturers. The challenge is to identify significant adoption factors to ensure effective adoption of…

  2. Interactions between genetic variants of folate metabolism genes and lifestyle affect plasma homocysteine concentrations in the Boston Puerto Rican Population

    Science.gov (United States)

    Results of studies investigating relationships between lifestyle factors and elevated plasma homocysteine (Hcy), an independent risk factor for cardiovascular disease, are conflicting. The objective of this study was to investigate genetic and lifestyle factors and their interactions on plasma Hcy c...

  3. The Natural Interactive Walking Project and Emergence of Its Results in Research on Rhythmic Walking Interaction and the Role of Footsteps in Affecting Body Ownership

    DEFF Research Database (Denmark)

    Maculewicz, Justyna; Sikström, Erik; Serafin, Stefania

    2015-01-01

    which are interesting in a broader context of interactive walking with audio and haptic feedback to present and discuss the developed systems for gait analysis and feedback presentation, but also, what is even more interesting to show how it influence humans behavior and perception. We hope also to open...... a discussion on why we actually can manipulate our behavior and show the importance of explaining it from the neurological perspective. We start with a general introduction, moving on to more specific parts of the project, that are followed by the results of the research which were conducted after project...

  4. Pulse treatment with the proteasome inhibitor bortezomib inhibits osteoclast resorptive activity in clinically relevant conditions

    DEFF Research Database (Denmark)

    Boissy, P; Levin Andersen, Thomas; Lund, T;

    2008-01-01

    Myeloma bone disease is due to bone degradation by osteoclasts, and absence of repair by bone forming osteoblasts. Recent observations suggest that the anti-myeloma drug bortezomib, a proteasome inhibitor, stimulates bone formation and may inhibit bone resorption. Here, we tested bortezomib...... on cultured osteoclasts in conditions mimicking the pulse treatment used in the clinic, thereby avoiding continuous proteasome inhibition and unselective toxicity. A 3h pulse with 25nM bortezomib followed by a 3-day culture in its absence markedly inhibited osteoclast activity as evaluated through bone...... resorption, TRAcP release, and RANKL-induced NF-kappaB translocation into nuclei, an event dependent on proteasomes and critical for osteoclast function. The effect on TRAcP was maximal during the first 24h post-pulse, and then tended to subside. Importantly, applying this pulse treatment to cultured myeloma...

  5. Deimination of the myelin basic protein decelerates its proteasome-mediated metabolism.

    Science.gov (United States)

    Kuzina, E S; Kudriaeva, A A; Glagoleva, I S; Knorre, V D; Gabibov, A G; Belogurov, A A

    2016-07-01

    Deimination of myelin basic protein (MBP) by peptidylarginine deiminase (PAD) prevents its binding to the proteasome and decelerates its degradation by the proteasome in mammalian cells. Potential anticancer drug tetrazole analogue of chloramidine 2, at concentrations greater than 1 µM inhibits the enzymatic activity of PAD in vitro. The observed acceleration of proteasome hydrolysis of MBP to antigenic peptides in the presence of PAD inhibitor may increase the efficiency of lesion of the central nervous system by cytotoxic lymphocytes in multiple sclerosis. We therefore suggest that clinical trials and the introduction of PAD inhibitors in clinical practice for the treatment of malignant neoplasms should be performed only after a careful analysis of their potential effect on the induction of autoimmune neurodegeneration processes. PMID:27599511

  6. Fluorescent Tools for In Vivo Studies on the Ubiquitin-Proteasome System.

    Science.gov (United States)

    Matilainen, Olli; Jha, Sweta; Holmberg, Carina I

    2016-01-01

    The ubiquitin-proteasome system (UPS) plays a key role in maintaining proteostasis by degrading most of the cellular proteins. Traditionally, UPS activity is studied in vitro, in yeast, or in mammalian cell cultures by using short-lived GFP-based UPS reporters. Here, we present protocols for two fluorescent tools facilitating real-time imaging of UPS activity in living animals. We have generated transgenic Caenorhabditis elegans (C. elegans) expressing a photoconvertible UbG76V-Dendra2 UPS reporter, which permits measurement of reporter degradation by the proteasome independently of reporter protein synthesis, and a fluorescent polyubiquitin-binding reporter for detection of the endogenous pool of Lys48-linked polyubiquitinated proteasomal substrates. These reporter systems facilitate cell- and tissue-specific analysis of UPS activity especially in young adult animals, but can also be used for studies during development, aging, and for example stress conditions. PMID:27613038

  7. Roles of the ubiquitin proteasome system in the effects of drugs of abuse

    Directory of Open Access Journals (Sweden)

    Nicolas eMassaly

    2015-01-01

    Full Text Available Because of its ability to regulate the abundance of selected proteins the ubiquitin proteasome system (UPS plays an important role in neuronal and synaptic plasticity. As a result various stages of learning and memory depend on UPS activity. Drug addiction, another phenomenon that relies on neuroplasticity, shares molecular substrates with memory processes. However the necessity of proteasome-dependent protein degradation for the development of addiction has been poorly studied. Here we first review evidences from the literature that drugs of abuse regulate the expression and activity of the UPS system in the brain. We then provide a list of proteins which have been shown to be targeted to the proteasome following drug treatment and could thus be involved in neuronal adaptations underlying behaviors associated with drug use and abuse. Finally we describe the few studies that addressed the need for UPS-dependent protein degradation in animal models of addiction-related behaviors.

  8. The influence of proteasome inhibitor on the expression of cardiomyocytes damage markers after incubation with doxorubicin

    Directory of Open Access Journals (Sweden)

    Tereszkiewicz Sylwia

    2014-06-01

    Full Text Available The aim of the study was to verify the thesis that the cardiotoxic effects of doxorubicin are connected with activation of the ubiquitin - proteasome pathway followed by protein degradation. The expression of myocardial damage markers - fatty acid binding protein (H-FABP and brain natriuretic peptide (BNP was evaluated in rat fetal cardiomyocytes simultaneously treated with doxorubicin and the proteasome inhibitor - bortezomib. The level of H-FABP and BNP protein under the influence of doxorubicin was decreased below the detection threshold with unchanged (H-FABP or elevated (BNP mRNA expression level. Against the expectations, the inhibitor of proteasome did not abolish this effect. The observed abnormal expression of BNP and H-FABP protein after doxorubicin treatment makes their diagnostic significance in anthracycline cardiotoxicity questionable.

  9. Trypanocidal activity of the proteasome inhibitor and anti-cancer drug bortezomib

    Directory of Open Access Journals (Sweden)

    Wang Xia

    2009-07-01

    Full Text Available Abstract The proteasome inhibitor and anti-cancer drug bortezomib was tested for in vitro activity against bloodstream forms of Trypanosoma brucei. The concentrations of bortezomib required to reduce the growth rate by 50% and to kill all trypanosomes were 3.3 nM and 10 nM, respectively. In addition, bortezomib was 10 times more toxic to trypanosomes than to human HL-60 cells. Moreover, exposure of trypanosomes to 10 nM bortezomib for 16 h was enough to kill 90% of the parasites following incubation in fresh medium. However, proteasomal peptidase activities of trypanosomes exposed to bortezomib were only inhibited by 10% and 30% indicating that the proteasome is not the main target of the drug. The results suggest that bortezomib may be useful as drug for the treatment of human African trypanosomiasis.

  10. Human papillomavirus 16 E2 interacts with neuregulin receptor degradation protein 1 affecting ErbB-3 expression in vitro and in clinical samples of cervical lesions.

    Science.gov (United States)

    Paolini, Francesca; Curzio, Gianfranca; Melucci, Elisa; Terrenato, Irene; Antoniani, Barbara; Carosi, Mariantonia; Mottolese, Marcella; Vici, Patrizia; Mariani, Luciano; Venuti, Aldo

    2016-05-01

    The ErbB tyrosine kinase receptors play a key role in regulating many cellular functions and human papillomaviruses (HPVs) may interact with transductional pathway of different growth factor receptors. Here, these interactions were analysed in W12 cell line carrying HPV 16 genome and in clinical samples. W12 cells, in which HPV16 becomes integrated during passages, were utilised to detect viral and ErbB family expression at early (W12E) and late passages (W12G). Interestingly, a strong reduction of ErbB-3 expression was observed in W12G. Loss of the E2 and E5 viral genes occurs in W12G and this may affect ErbB-3 receptor expression. E2 and E5 rescue experiments demonstrated that only E2 gene was able to restore ErbB-3 expression. E2 is a transcriptional factor but the expression levels of ErbB3 were unaffected and ErbB-3 promoter did not show any consensus sequence for E2, thus E2 may interact in another way with ErbB3. Indeed, HPV 16 E2 can modulate ErbB-3 by interacting with the ubiquitin ligase neuregulin receptor degradation protein 1 (Nrdp-1) that is involved in the regulation of this receptor, via ubiquitination and degradation. E2 co-immunoprecipitated in a complex with Nrdp-1 leading to hypothesise an involvement of this interaction in ErbB-3 regulation. In addition, 90% of the clinical samples with integrated virus and E2 loss showed no or low ErbB-3 positivity, confirming in vitro results. In conclusion, the new discovered interaction of HPV-16 E2 with Nrdp-1 may affect ErbB-3 expression. PMID:26963794

  11. Tomato 26S Proteasome subunit RPT4a regulates ToLCNDV transcription and activates hypersensitive response in tomato.

    Science.gov (United States)

    Sahu, Pranav Pankaj; Sharma, Namisha; Puranik, Swati; Chakraborty, Supriya; Prasad, Manoj

    2016-01-01

    Involvement of 26S proteasomal subunits in plant pathogen-interactions, and the roles of each subunit in independently modulating the activity of many intra- and inter-cellular regulators controlling physiological and defense responses of a plant were well reported. In this regard, we aimed to functionally characterize a Solanum lycopersicum 26S proteasomal subunit RPT4a (SlRPT4) gene, which was differentially expressed after Tomato leaf curl New Delhi virus (ToLCNDV) infection in tolerant cultivar H-88-78-1. Molecular analysis revealed that SlRPT4 protein has an active ATPase activity. SlRPT4 could specifically bind to the stem-loop structure of intergenic region (IR), present in both DNA-A and DNA-B molecule of the bipartite viral genome. Lack of secondary structure in replication-associated gene fragment prevented formation of DNA-protein complex suggesting that binding of SlRPT4 with DNA is secondary structure specific. Interestingly, binding of SlRPT4 to IR inhibited the function of RNA Pol-II and subsequently reduced the bi-directional transcription of ToLCNDV genome. Virus-induced gene silencing of SlRPT4 gene incited conversion of tolerant attributes of cultivar H-88-78-1 into susceptibility. Furthermore, transient overexpression of SlRPT4 resulted in activation of programmed cell death and antioxidant enzymes system. Overall, present study highlights non-proteolytic function of SlRPT4 and their participation in defense pathway against virus infection in tomato. PMID:27252084

  12. Different degree in proteasome malfunction has various effects on root growth possibly through preventing cell division and promoting autophagic vacuolization.

    Directory of Open Access Journals (Sweden)

    Xianyong Sheng

    Full Text Available The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated proteins using immunofluorescence labeling, and autophagy activity using LysoTracker and MDC. The results indicated that lower concentration of proteasome inhibitors promoted root growth, whereas higher concentration of inhibitors had the opposite effects. The accumulation of cyclin B was linked to MG132-induced decline in meristem size, indicating that proteasome malfunction prevented cell division. Besides, MG132-induced accumulation of the ubiquitinated proteins was associated with the increasing fluorescence signal of LysoTracker and MDC in the elongation zone, revealing a link between the activation of autophagy and proteasome malfunction. These results suggest that weak proteasome malfunction activates moderate autophagy and promotes cell elongation, which compensates the inhibitor-induced reduction of cell division, resulting in long roots. Whereas strong proteasome malfunction induces severe autophagy and disturbs cell elongation, resulting in short roots.

  13. Proteasome nuclear import mediated by Arc3 can influence efficient DNA damage repair and mitosis in Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Cabrera, Alvaro R. Fuentes; Sha, Zhe; Vadakkan, Tegy J;

    2010-01-01

    deficiencies; when its expression is repressed, proteasome deficiencies intensify. Arp2/3 is best known for regulating membrane dynamics and vesicular transport; thus, we performed photobleaching experiments and showed that proteasomes are readily imported into the nucleus but exit the nucleus slowly...

  14. Interaction Between Syndromic and Non-Syndromic Factors Affecting Speech and Language Development in Treacher-Collins Syndrome

    OpenAIRE

    Marziyeh Poorjavad

    2011-01-01

    Background: Treacher-Collins syndrome is a congenital craniofacial disorder with multiple anomalies. This syndrome affects the maxilla, mandible, eyes, middle and outer ears, and soft palate. Conductive hearing loss due to the deformities of the middle and external ears is prevalent. The characteristics of this syndrome include multiple and serious threats to normal communication development in children. In this study, speech and language features of a Persian speaking child with this syndrom...

  15. Osmolyte Trimethylamine-N-Oxide Does Not Affect the Strength of Hydrophobic Interactions: Origin of Osmolyte Compatibility

    OpenAIRE

    Athawale, Manoj V.; Dordick, Jonathan S.; Garde, Shekhar

    2005-01-01

    Osmolytes are small organic solutes accumulated at high concentrations by cells/tissues in response to osmotic stress. Osmolytes increase thermodynamic stability of folded proteins and provide protection against denaturing stresses. The mechanism of osmolyte compatibility and osmolyte-induced stability has, therefore, attracted considerable attention in recent years. However, to our knowledge, no quantitative study of osmolyte effects on the strength of hydrophobic interactions has been repor...

  16. Direct interaction of natural and synthetic catechins with signal transducer activator of transcription 1 affects both its phosphorylation and activity

    KAUST Repository

    Menegazzi, Marta

    2013-12-10

    Our previous studies showed that (-)-epigallocatechin-3-gallate (EGCG) inhibits signal transducer activator of transcription 1 (STAT1) activation. Since EGCG may be a promising lead compound for new anti-STAT1 drug design, 15 synthetic catechins, characterized by the (-)-gallocatechin-3-gallate stereochemistry, were studied in the human mammary MDA-MB-231 cell line to identify the minimal structural features that preserve the anti-STAT1 activity. We demonstrate that the presence of three hydroxyl groups of B ring and one hydroxyl group in D ring is essential to preserve their inhibitory action. Moreover, a possible molecular target of these compounds in the STAT1 pathway was investigated. Our results demonstrate a direct interaction between STAT1 protein and catechins displaying anti-STAT1 activity. In particular, surface plasmon resonance (SPR) analysis and molecular modeling indicate the presence of two putative binding sites (a and b) with different affinity. Based on docking data, site-directed mutagenesis was performed, and interaction of the most active catechins with STAT1 was studied with SPR to test whether Gln518 on site a and His568 on site b could be important for the catechin-STAT1 interaction. Data indicate that site b has higher affinity for catechins than site a as the highest affinity constant disappears in the H568ASTAT1 mutant. Furthermore, Janus kinase 2 (JAK2) kinase assay data suggest that the contemporary presence in vitro of STAT1 and catechins inhibits JAK2-elicited STAT1 phosphorylation. The very tight catechin-STAT1 interaction prevents STAT1 phosphorylation and represents a novel, specific and efficient molecular mechanism for the inhibition of STAT1 activation. © Copyright 2014 Federation of European Biochemical Societies. All rights reserved.

  17. Factors affecting the interactions between beta-lactoglobulin and fatty acids as revealed in molecular dynamics simulations.

    Science.gov (United States)

    Yi, Changhong; Wambo, Thierry O

    2015-09-21

    Beta-lactoglobulin (BLG), a bovine dairy protein, is a promiscuously interacting protein that can bind multiple hydrophobic ligands. Fatty acids (FAs), common hydrophobic molecules bound to BLG, are important sources of fuel for life because they yield large quantities of ATP when metabolized. The binding affinity increases with the length of the ligands, indicating the importance of the van der Waals (vdW) interactions between the hydrocarbon tail and the hydrophobic calyx of BLG. An exception to this rule is caprylic acid (OCA) which is two-carbon shorter but has a stronger binding affinity than capric acid. Theoretical calculations in the current literature are not accurate enough to shed light on the underlying physics of this exception. The computed affinity values are greater for longer fatty acids without respect for the caprylic exception and those values are generally several orders of magnitude away from the experimental data. In this work, we used hybrid steered molecular dynamics to accurately compute the binding free energies between BLG and the five saturated FAs of 8 to 16 carbon atoms. The computed binding free energies agree well with experimental data not only in rank but also in absolute values. We gained insights into the exceptional behavior of caprylic acid in the computed values of entropy and electrostatic interactions. We found that the electrostatic interaction between the carboxyl group of caprylic acid and the two amino groups of K60/69 in BLG is much stronger than the vdW force between the OCA's hydrophobic tail and the BLG calyx. This pulls OCA to the top of the beta barrel where it is easier to fluctuate, giving rise to greater entropy of OCA at the binding site. PMID:26272099

  18. Crosstalk between the proteasome system and autophagy in the clearance of α-synuclein

    Institute of Scientific and Technical Information of China (English)

    Fang YANG; Ya-ping YANG; Cheng-jie MAO; Ling LIU; Hui-fen ZHENG; Li-fang HU; Chun-feng LIU

    2013-01-01

    A growing body of evidence suggests that α-synuclein accumulation may play an important role in the pathogenesis of Parkinson's disease.The aim of this study was to investigate the roles of the proteasome and autophagy pathways in the clearance of wild-type and mutant α-synuclein in PC12 cells.Methods:PC12 cells overexpressing either wild-type or A30P mutant α-synuclein were treated with the proteasome inhibitor epoxomicin,the macroautophagy inhibitor 3-MA and the macroautophagy activator rapamycin alone or in combination.The cell viability was assessed using MTT assay.Immunofluorescence and Western blot analysis were used to detect the level of α-synuclein,LAMP-2A,E1 activase,and E2 ligase in the cells.Chymotrypsin-like proteasomal activity was measured using a commercial kit.Results:When the proteasome and macroautophagy in the wild-type and mutant cells were inhibited with epoxomicin and 3-MA,respectively,the cell viability was significantly decreased,and the α-synuclein level was increased.Both epoxomicin and 3-MA activated the chaperone-mediated autophagy (CMA) by increasing the level of the CMA-limiting enzyme LAMP-2A.Furthermore,3-MA or epoxomicin significantly decreased chymotrypsin-like proteasomal activity.3-MA or epoxomicin did not change E1 activase expression in either mutant or wild-type cells,but increased E2 ligase expression,especially when used together.Macroautophagy inducer rapamycin increased the cell viability and reduced epoxomicin-induced α-synuclein accumulation.Interestingly,CMA was also activated by rapamycin.Conclusion:Our results demonstrate the existence of complex crosstalk between different forms of autophagy and between autophagy and the proteasome pathway in the clearance of α-synuclein in PC12 cells.

  19. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions...... interaction between a human operator and an artificial actor or agent. We can apply insights from puppetry to develop culturally-aware robots. Here we describe the development of a robotic marionette theatre wherein robotic controllers assume the role of human puppeteers. The system has been built, tested......, and demonstrated in public settings. We then describe INTERACT, a proposed research project that stages the robotic marionettes in a live performance. The interdisciplinary project brings humanities research to bear on scientific and technological inquiry, and culminates in the development a live performance which...

  20. Genotype-by-environment interactions and adaptation to local temperature affect immunity and fecundity in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Brian P Lazzaro

    2008-03-01

    Full Text Available Natural populations of most organisms harbor substantial genetic variation for resistance to infection. The continued existence of such variation is unexpected under simple evolutionary models that either posit direct and continuous natural selection on the immune system or an evolved life history "balance" between immunity and other fitness traits in a constant environment. However, both local adaptation to heterogeneous environments and genotype-by-environment interactions can maintain genetic variation in a species. In this study, we test Drosophila melanogaster genotypes sampled from tropical Africa, temperate northeastern North America, and semi-tropical southeastern North America for resistance to bacterial infection and fecundity at three different environmental temperatures. Environmental temperature had absolute effects on all traits, but there were also marked genotype-by-environment interactions that may limit the global efficiency of natural selection on both traits. African flies performed more poorly than North American flies in both immunity and fecundity at the lowest temperature, but not at the higher temperatures, suggesting that the African population is maladapted to low temperature. In contrast, there was no evidence for clinal variation driven by thermal adaptation within North America for either trait. Resistance to infection and reproductive success were generally uncorrelated across genotypes, so this study finds no evidence for a fitness tradeoff between immunity and fecundity under the conditions tested. Both local adaptation to geographically heterogeneous environments and genotype-by-environment interactions may explain the persistence of genetic variation for resistance to infection in natural populations.

  1. Genotype-by-Environment Interactions and Adaptation to Local Temperature Affect Immunity and Fecundity in Drosophila melanogaster

    Science.gov (United States)

    Lazzaro, Brian P.; Flores, Heather A.; Lorigan, James G.; Yourth, Christopher P.

    2008-01-01

    Natural populations of most organisms harbor substantial genetic variation for resistance to infection. The continued existence of such variation is unexpected under simple evolutionary models that either posit direct and continuous natural selection on the immune system or an evolved life history “balance” between immunity and other fitness traits in a constant environment. However, both local adaptation to heterogeneous environments and genotype-by-environment interactions can maintain genetic variation in a species. In this study, we test Drosophila melanogaster genotypes sampled from tropical Africa, temperate northeastern North America, and semi-tropical southeastern North America for resistance to bacterial infection and fecundity at three different environmental temperatures. Environmental temperature had absolute effects on all traits, but there were also marked genotype-by-environment interactions that may limit the global efficiency of natural selection on both traits. African flies performed more poorly than North American flies in both immunity and fecundity at the lowest temperature, but not at the higher temperatures, suggesting that the African population is maladapted to low temperature. In contrast, there was no evidence for clinal variation driven by thermal adaptation within North America for either trait. Resistance to infection and reproductive success were generally uncorrelated across genotypes, so this study finds no evidence for a fitness tradeoff between immunity and fecundity under the conditions tested. Both local adaptation to geographically heterogeneous environments and genotype-by-environment interactions may explain the persistence of genetic variation for resistance to infection in natural populations. PMID:18369474

  2. Interactions

    DEFF Research Database (Denmark)

    The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists such as ......The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists...... also key figures in the philosophical discussions of nature and science - from philosophical tendencies like logical empiricism via critical rationalism to various neo-Kantian trends....

  3. Computational analysis and modeling of cleavage by the immunoproteasome and the constitutive proteasome

    Directory of Open Access Journals (Sweden)

    Lafuente Esther M

    2010-09-01

    Full Text Available Abstract Background Proteasomes play a central role in the major histocompatibility class I (MHCI antigen processing pathway. They conduct the proteolytic degradation of proteins in the cytosol, generating the C-terminus of CD8 T cell epitopes and MHCI-peptide ligands (P1 residue of cleavage site. There are two types of proteasomes, the constitutive form, expressed in most cell types, and the immunoproteasome, which is constitutively expressed in mature dendritic cells. Protective CD8 T cell epitopes are likely generated by the immunoproteasome and the constitutive proteasome, and here we have modeled and analyzed the cleavage by these two proteases. Results We have modeled the immunoproteasome and proteasome cleavage sites upon two non-overlapping sets of peptides consisting of 553 CD8 T cell epitopes, naturally processed and restricted by human MHCI molecules, and 382 peptides eluted from human MHCI molecules, respectively, using N-grams. Cleavage models were generated considering different epitope and MHCI-eluted fragment lengths and the same number of C-terminal flanking residues. Models were evaluated in 5-fold cross-validation. Judging by the Mathew's Correlation Coefficient (MCC, optimal cleavage models for the proteasome (MCC = 0.43 ± 0.07 and the immunoproteasome (MCC = 0.36 ± 0.06 were obtained from 12-residue peptide fragments. Using an independent dataset consisting of 137 HIV1-specific CD8 T cell epitopes, the immunoproteasome and proteasome cleavage models achieved MCC values of 0.30 and 0.18, respectively, comparatively better than those achieved by related methods. Using ROC analyses, we have also shown that, combined with MHCI-peptide binding predictions, cleavage predictions by the immunoproteasome and proteasome models significantly increase the discovery rate of CD8 T cell epitopes restricted by different MHCI molecules, including A*0201, A*0301, A*2402, B*0702, B*2705. Conclusions We have developed models that are specific

  4. NIR is degraded by the anaphase-promoting complex proteasome pathway

    Directory of Open Access Journals (Sweden)

    Jeong Ho Myong

    2014-01-01

    Full Text Available Novel INHAT Repressor (NIR is a histone acetylation inhibitor that can directly bind histone complexes and the tumor suppressors p53 and p63. Because NIR is mainly localized in the nucleolus and disappears from the nucleolus upon RNase treatment, it is thought to bind RNA or ribonucleoproteins. When NIR moves to the cytoplasm, it is immediately degraded; this degradation was blocked by MG132, a proteasome inhibitor. Furthermore, the central domain of NIR specifically bound APC-CCdh1. These data show that the stability of NIR is governed by the ubiquitin/proteasome pathway.

  5. Plant ubiquitin-proteasome pathway and its role in gibberellin signaling

    Institute of Scientific and Technical Information of China (English)

    Feng Wang; Xing Wang Deng

    2011-01-01

    The ubiquitin-proteasome system (UPS) in plants,like in other eukaryotes,targets numerous intracellular regulators and thus modulates almost every aspect of growth and development.The well-known and best-characterized outcome of ubiquitination is mediating target protein degradation via the 26S proteasome,which represents the major selective protein degradation pathway conserved among eukaryotes.In this review,we will discuss the molecular composition,regulation and function of plant UPS,with a major focus on how DELLA protein degradation acts as a key in gibberellin signal transduction and its implication in the regulation of plant growth.

  6. Proteasomal activities in the claw muscle tissue of European lobster, Homarus gammarus, during larval development.

    Science.gov (United States)

    Götze, Sandra; Saborowski, Reinhard

    2011-10-01

    Decapod crustaceans grow discontinuously and gain size through complex molt processes. The molt comprises the loss of the old cuticle and, moreover, substantial reduction and re-organization of muscles and connective tissues. In adult lobsters, the muscle tissue of the massive claws undergoes significant atrophy of 40-75% before ecdysis. The degradation of this tissue is facilitated by calcium-dependent proteases and by the proteasome, an intra-cellular proteolytic multi-enzyme complex. In contrast to the adults, the involvement of the proteasome during the larval development is yet not validated. Therefore, we developed micro-methods to measure the 20S and the 26S proteasomal activities within mg- and sub-mg-quantities of the larval claw tissue of the European lobster, Homarus gammarus. Within the three larval stages (Z1-3) we distinguished between sub-stages of freshly molted/hatched (post-molt), inter-molt, and ready to molt (pre-molt) larvae. Juveniles were analyzed in the post-molt and in the inter-molt stage. The trypsin-like, the chymotrypsin-like, and the peptidyl-glutamyl peptide hydrolase activity (PGPH) of the 20S proteasome increased distinctly from freshly hatched larvae to pre-molt Z1. During the Z2 stage, the activities were highest in the post-molt animals, decreased in the inter-molt animals and increased again in the pre-molt animals. A similar but less distinct trend was evident in the Z3 stages. In the juveniles, the proteasomal activities decreased toward the lowest values. A similar pattern was present for the chymotrypsin-like activity of the 26S proteasome. The results show that the proteasome plays a significant role during the larval development of lobsters. This is not only reflected by the elevated activities, but also by the continuous change of the trypsin/chymotrypsin-ratio which may indicate a shift in the subunit composition of the proteasome and, thus, a biochemical adjustment to better cope with elevated protein turnover rates

  7. Uch2/Uch37 is the major deubiquitinating enzyme associated with the 26S proteasome in fission yeast

    DEFF Research Database (Denmark)

    Stone, Miranda; Hartmann-Petersen, Rasmus; Seeger, Michael;

    2004-01-01

    Conjugation of proteins to ubiquitin plays a central role for a number of cellular processes including endocytosis, DNA repair and degradation by the 26S proteasome. However, ubiquitination is reversible as a number of deubiquitinating enzymes mediate the disassembly of ubiquitin-protein conjugates....... Some deubiquitinating enzymes are associated with the 26S proteasome contributing to and regulating the particle's activity. Here, we characterise fission yeast Uch2 and Ubp6, two proteasome associated deubiquitinating enzymes. The human orthologues of these enzymes are known as Uch37 and Usp14......, respectively. We report that the subunit Uch2/Uch37 is the major deubiquitinating enzyme associated with the fission yeast 26S proteasome. In contrast, the activity of Ubp6 appears to play a more regulatory and/or structural role involving the proteasome subunits Mts1/Rpn9, Mts2/Rpt2 and Mts3/Rpn12, as Ubp6...

  8. Large-scale biotic interaction effects - tree cover interacts with shade toler-ance to affect distribution patterns of herb and shrub species across the Alps

    DEFF Research Database (Denmark)

    Nieto-Lugilde, Diego; Lenoir, Jonathan; Abdulhak, Sylvain;

    2012-01-01

    occurrence on light-demanding species via size-asymmetric competition for light, but a facilitative effect on shade-tolerant species. In order to compare the relative importance of tree cover, four models with different combinations of variables (climate, soil and tree cover) were run for each species. Then......, we simulated a removal experiment by comparing the elevational distribution of each species under high and low tree cover. Tree cover improved model performances and species’ response curves to a tree cover gradient varied depending on their shade tolerance, supporting the hypothesized antagonistic...... role. Results indicated that high tree cover causes range contraction, especially at the upper limit, for light-demanding species, whereas it causes shade-tolerant species to extend their range upwards and downwards. Tree cover thus drives plant-plant interactions to shape plant species distribution...

  9. Sorafenib enhances proteasome inhibitor-mediated cytotoxicity via inhibition of unfolded protein response and keratin phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Honma, Yuichi; Harada, Masaru, E-mail: msrharada@med.uoeh-u.ac.jp

    2013-08-15

    Hepatocellular carcinoma (HCC) is highly resistant to conventional systemic therapies and prognosis for advanced HCC patients remains poor. Recent studies of the molecular mechanisms responsible for tumor initiation and progression have identified several potential molecular targets in HCC. Sorafenib is a multi-kinase inhibitor shown to have survival benefits in advanced HCC. It acts by inhibiting the serine/threonine kinases and the receptor type tyrosine kinases. In preclinical experiments sorafenib had anti-proliferative activity in hepatoma cells and it reduced tumor angiogenesis and increased apoptosis. Here, we demonstrate for the first time that the cytotoxic mechanisms of sorafenib include its inhibitory effects on protein ubiquitination, unfolded protein response (UPR) and keratin phosphorylation in response to endoplasmic reticulum (ER) stress. Moreover, we show that combined treatment with sorafenib and proteasome inhibitors (PIs) synergistically induced a marked increase in cell death in hepatoma- and hepatocyte-derived cells. These observations may open the way to potentially interesting treatment combinations that may augment the effect of sorafenib, possibly including drugs that promote ER stress. Because sorafenib blocked the cellular defense mechanisms against hepatotoxic injury not only in hepatoma cells but also in hepatocyte-derived cells, we must be careful to avoid severe liver injury. -- Graphical abstract: Display Omitted -- Highlights: •We examined the cytotoxic mechanisms of sorafenib in hepatoma cells. •Sorafenib induces cell death via apoptotic and necrotic fashion. •Sorafenib inhibits protein ubiquitination and unfolded protein response. •Autophagy induced by sorafenib may affect its cytotoxicity. •Sorafenib inhibits keratin phosphorylation and cytoplasmic inclusion formation.

  10. Patient-Provider Interactions Affect Symptoms in Gastroesophageal Reflux Disease: A Pilot Randomized, Double-Blind, Placebo-Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Michelle L Dossett

    Full Text Available It is unclear whether the benefits that some patients derive from complementary and integrative medicine (CIM are related to the therapies recommended or to the consultation process as some CIM provider visits are more involved than conventional medical visits. Many patients with gastrointestinal conditions seek out CIM therapies, and prior work has demonstrated that the quality of the patient-provider interaction can improve health outcomes in irritable bowel syndrome, however, the impact of this interaction on gastroesophageal reflux disease (GERD is unknown. We aimed to assess the safety and feasibility of conducting a 2 x 2 factorial design study preliminarily exploring the impact of the patient-provider interaction, and the effect of an over-the-counter homeopathic product, Acidil, on symptoms and health-related quality of life in subjects with GERD.24 subjects with GERD-related symptoms were randomized in a 2 x 2 factorial design to receive 1 either a standard visit based on an empathic conventional primary care evaluation or an expanded visit with questions modeled after a CIM consultation and 2 either Acidil or placebo for two weeks. Subjects completed a daily GERD symptom diary and additional measures of symptom severity and health-related quality of life.There was no significant difference in GERD symptom severity between the Acidil and placebo groups from baseline to follow-up (p = 0.41, however, subjects who received the expanded visit were significantly more likely to report a 50% or greater improvement in symptom severity compared to subjects who received the standard visit (p = 0.01. Total consultation length, perceived empathy, and baseline beliefs in CIM were not associated with treatment outcomes.An expanded patient-provider visit resulted in greater GERD symptom improvement than a standard empathic medical visit. CIM consultations may have enhanced placebo effects, and further studies to assess the active components of this

  11. Characterization of conserved arginine residues on Cdt1 that affect licensing activity and interaction with Geminin or Mcm complex.

    Science.gov (United States)

    You, Zhiying; Ode, Koji L; Shindo, Mayumi; Takisawa, Haruhiko; Masai, Hisao

    2016-05-01

    All organisms ensure once and only once replication during S phase through a process called replication licensing. Cdt1 is a key component and crucial loading factor of Mcm complex, which is a central component for the eukaryotic replicative helicase. In higher eukaryotes, timely inhibition of Cdt1 by Geminin is essential to prevent rereplication. Here, we address the mechanism of DNA licensing using purified Cdt1, Mcm and Geminin proteins in combination with replication in Xenopus egg extracts. We mutagenized the 223th arginine of mouse Cdt1 (mCdt1) to cysteine or serine (R-S or R-C, respectively) and 342nd and 346th arginines constituting an arginine finger-like structure to alanine (RR-AA). The RR-AA mutant of Cdt1 could not only rescue the DNA replication activity in Cdt1-depleted extracts but also its specific activity for DNA replication and licensing was significantly increased compared to the wild-type protein. In contrast, the R223 mutants were partially defective in rescue of DNA replication and licensing. Biochemical analyses of these mutant Cdt1 proteins indicated that the RR-AA mutation disabled its functional interaction with Geminin, while R223 mutations resulted in ablation in interaction with the Mcm2∼7 complex. Intriguingly, the R223 mutants are more susceptible to the phosphorylation-induced inactivation or chromatin dissociation. Our results show that conserved arginine residues play critical roles in interaction with Geminin and Mcm that are crucial for proper conformation of the complexes and its licensing activity. PMID:26940553

  12. Charged histidine affects alpha-helix stability at all positions in the helix by interacting with the backbone charges.

    OpenAIRE

    Armstrong, K M; Baldwin, R L

    1993-01-01

    To determine whether a charged histidine side chain affects alpha-helix stability only when histidine is close to one end of the helix or also when it is in the central region, we substitute a single histidine residue at many positions in two reference peptides and measure helix stability and histidine pKa. The position of a charged histidine residue has a major effect on helix stability in 0.01 M NaCl: the helix content of a 17-residue peptide is 24% when histidine is at position 3 compared ...

  13. NH4+ enrichment and UV radiation interact to affect the photosynthesis and nitrogen uptake of Gracilaria lemaneiformis (Rhodophyta).

    Science.gov (United States)

    Xu, Zhiguang; Gao, Kunshan

    2012-01-01

    Solar ultraviolet radiation (UVR, 280-400 nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280-315 nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315-400 nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia.

  14. Interaction Between Syndromic and Non-Syndromic Factors Affecting Speech and Language Development in Treacher-Collins Syndrome

    Directory of Open Access Journals (Sweden)

    Marziyeh Poorjavad

    2011-09-01

    Full Text Available Background: Treacher-Collins syndrome is a congenital craniofacial disorder with multiple anomalies. This syndrome affects the maxilla, mandible, eyes, middle and outer ears, and soft palate. Conductive hearing loss due to the deformities of the middle and external ears is prevalent. The characteristics of this syndrome include multiple and serious threats to normal communication development in children. In this study, speech and language features of a Persian speaking child with this syndrome are presented.Case: The case was an 8-year old girl with Treacher-Collins syndrome and bilateral moderate conductive hearing loss due to atretic canal. In language and speech assessments, moderate hypernasality, numerous compensatory errors and morphosyntactic deficits were observed. There were 13 phonemes that were incorrectly produced at least in one position. Besides, she used 22 types of phonological processes that were abnormal and disappear before the age of three in normal Persian speaking children.Conclusion: Moderate hearing loss, velopharyngeal incompetency, malocclusion and dental anomalies, attention deficit/hyperactivity disorder (ADHD and environmental factors resulted in severe speech and language disorders in this case. These disorders affected her academic performance as well. Moderate hypernasality, numerous compensatory errors, and excessive and abnormal use of phonological processes were not presented as prevalent characteristics of Treacher-Collins syndrome in other resources.

  15. Religion priming and an oxytocin receptor gene (OXTR) polymorphism interact to affect self-control in a social context.

    Science.gov (United States)

    Sasaki, Joni Y; Mojaverian, Taraneh; Kim, Heejung S

    2015-02-01

    Using a genetic moderation approach, this study examines how an experimental prime of religion impacts self-control in a social context, and whether this effect differs depending on the genotype of an oxytocin receptor gene (OXTR) polymorphism (rs53576). People with different genotypes of OXTR seem to have different genetic orientations toward sociality, which may have consequences for the way they respond to religious cues in the environment. In order to determine whether the influence of religion priming on self-control is socially motivated, we examine whether this effect is stronger for people who have OXTR genotypes that should be linked to greater rather than less social sensitivity (i.e., GG vs. AA/AG genotypes). The results showed that experimentally priming religion increased self-control behaviors for people with GG genotypes more so than people with AA/AG genotypes. Furthermore, this Gene × Religion interaction emerged in a social context, when people were interacting face to face with another person. This research integrates genetic moderation and social psychological approaches to address a novel question about religion's influence on self-control behavior, which has implications for coping with distress and psychopathology. These findings also highlight the importance of the social context for understanding genetic moderation of psychological effects.

  16. Mutations in the DNA-binding domain of NR2E3 affect in vivo dimerization and interaction with CRX.

    Directory of Open Access Journals (Sweden)

    Raphael Roduit

    Full Text Available BACKGROUND: NR2E3 (PNR is an orphan nuclear receptor essential for proper photoreceptor determination and differentiation. In humans, mutations in NR2E3 have been associated with the recessively inherited enhanced short wavelength sensitive (S- cone syndrome (ESCS and, more recently, with autosomal dominant retinitis pigmentosa (adRP. NR2E3 acts as a suppressor of the cone generation program in late mitotic retinal progenitor cells. In adult rod photoreceptors, NR2E3 represses cone-specific gene expression and acts in concert with the transcription factors CRX and NRL to activate rod-specific genes. NR2E3 and CRX have been shown to physically interact in vitro through their respective DNA-binding domains (DBD. The DBD also contributes to homo- and heterodimerization of nuclear receptors. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed NR2E3 homodimerization and NR2E3/CRX complex formation in an in vivo situation by Bioluminescence Resonance Energy Transfer (BRET(2. NR2E3 wild-type protein formed homodimers in transiently transfected HEK293T cells. NR2E3 homodimerization was impaired in presence of disease-causing mutations in the DBD, except for the p.R76Q and p.R104W mutant proteins. Strikingly, the adRP-linked p.G56R mutant protein interacted with CRX with a similar efficiency to that of NR2E3 wild-type and p.R311Q proteins. In contrast, all other NR2E3 DBD-mutant proteins did not interact with CRX. The p.G56R mutant protein was also more effective in abolishing the potentiation of rhodospin gene transactivation by the NR2E3 wild-type protein. In addition, the p.G56R mutant enhanced the transrepression of the M- and S-opsin promoter, while all other NR2E3 DBD-mutants did not. CONCLUSIONS/SIGNIFICANCE: These results suggest different disease mechanisms in adRP- and ESCS-patients carrying NR2E3 mutations. Titration of CRX by the p.G56R mutant protein acting as a repressor in trans may account for the severe clinical phenotype in adRP patients.

  17. A Bowman-Birk inhibitor induces apoptosis in human breast adenocarcinoma through mitochondrial impairment and oxidative damage following proteasome 20S inhibition.

    Science.gov (United States)

    Mehdad, A; Brumana, G; Souza, A A; Barbosa, Jarg; Ventura, M M; de Freitas, S M

    2016-01-01

    Proteasome inhibitors are emerging as a new class of chemopreventive agents and have gained huge importance as potential pharmacological tools in breast cancer treatment. Improved understanding of the role played by proteases and their specific inhibitors in humans offers novel and challenging opportunities for preventive and therapeutic intervention. In this study, we demonstrated that the Bowman-Birk protease inhibitor from Vigna unguiculata seeds, named black-eyed pea trypsin/chymotrypsin Inhibitor (BTCI), potently suppresses human breast adenocarcinoma cell viability by inhibiting the activity of proteasome 20S. BTCI induced a negative growth effect against a panel of breast cancer cells, with a concomitant cytostatic effect at the G2/M phase of the cell cycle and an increase in apoptosis, as observed by an augmented number of cells at the sub-G1 phase and annexin V-fluorescin isothiocyanate (FITC)/propidium iodide (PI) staining. In contrast, BTCI exhibited no cytotoxic effect on normal mammary epithelial cells. Moreover, the increased levels of intracellular reactive oxygen species (ROS) and changes in the mitochondrial membrane potential in cells treated with BTCI indicated mitochondrial damage as a crucial cellular event responsible for the apoptotic process. The higher activity of caspase in tumoral cells treated with BTCI in comparison with untreated cells suggests that BTCI induces apoptosis in a caspase-dependent manner. BTCI affected NF-kB target gene expression in both non invasive and invasive breast cancer cell lines, with the effect highly pronounced in the invasive cells. An increased expression of interleukin-8 (IL-8) in both cell lines was also observed. Taken together, these results suggest that BTCI promotes apoptosis through ROS-induced mitochondrial damage following proteasome inhibition. These findings highlight the pharmacological potential and benefit of BTCI in breast cancer treatment. PMID:27551492

  18. A Bowman–Birk inhibitor induces apoptosis in human breast adenocarcinoma through mitochondrial impairment and oxidative damage following proteasome 20S inhibition

    Science.gov (United States)

    Mehdad, A; Brumana, G; Souza, AA; Barbosa, JARG; Ventura, MM; de Freitas, SM

    2016-01-01

    Proteasome inhibitors are emerging as a new class of chemopreventive agents and have gained huge importance as potential pharmacological tools in breast cancer treatment. Improved understanding of the role played by proteases and their specific inhibitors in humans offers novel and challenging opportunities for preventive and therapeutic intervention. In this study, we demonstrated that the Bowman–Birk protease inhibitor from Vigna unguiculata seeds, named black-eyed pea trypsin/chymotrypsin Inhibitor (BTCI), potently suppresses human breast adenocarcinoma cell viability by inhibiting the activity of proteasome 20S. BTCI induced a negative growth effect against a panel of breast cancer cells, with a concomitant cytostatic effect at the G2/M phase of the cell cycle and an increase in apoptosis, as observed by an augmented number of cells at the sub-G1 phase and annexin V-fluorescin isothiocyanate (FITC)/propidium iodide (PI) staining. In contrast, BTCI exhibited no cytotoxic effect on normal mammary epithelial cells. Moreover, the increased levels of intracellular reactive oxygen species (ROS) and changes in the mitochondrial membrane potential in cells treated with BTCI indicated mitochondrial damage as a crucial cellular event responsible for the apoptotic process. The higher activity of caspase in tumoral cells treated with BTCI in comparison with untreated cells suggests that BTCI induces apoptosis in a caspase-dependent manner. BTCI affected NF-kB target gene expression in both non invasive and invasive breast cancer cell lines, with the effect highly pronounced in the invasive cells. An increased expression of interleukin-8 (IL-8) in both cell lines was also observed. Taken together, these results suggest that BTCI promotes apoptosis through ROS-induced mitochondrial damage following proteasome inhibition. These findings highlight the pharmacological potential and benefit of BTCI in breast cancer treatment. PMID:27551492

  19. Effect of inhibition of the Ubiquitin-Proteasome System and Hsp90 on growth and survival of Rhabdomyosarcoma cells in vitro

    Directory of Open Access Journals (Sweden)

    Peron Marica

    2012-06-01

    Full Text Available Abstract Background The ubiquitin-proteasome system (UPS and the heat shock response (HSR are two critical regulators of cell homeostasis, as their inhibition affects growth and survival of normal cells, as well as stress response and invasiveness of cancer cells. We evaluated the effects of the proteasome inhibitor Bortezomib and of 17-DMAG, a competitive inhibitor of Hsp90, in rhabdomyosarcoma (RMS cells, and analyzed the efficacy of single-agent exposures with combination treatments. Methods To assess cytotoxicity induced by Bortezomib and 17-DMAG in RMS cells, viability was measured by MTT assay after 24, 48 and 72 hours. Western blotting and immunofluorescence analyses were carried out to elucidate the mechanisms of action. Apoptosis was measured by FACS with Annexin-V-FITC and Propidium Iodide. Results Bortezomib and 17-DMAG, when combined at single low-toxic concentrations, enhanced growth inhibition of RMS cells, with signs of autophagy that included intensive cytoplasmic vacuolization and conversion of cytosolic LC3-I protein to its autophagosome-associated form. Treatment with lysosomal inhibitor chloroquine facilitates apoptosis, whereas stimulation of autophagy by rapamycin prevents LC3-I conversion and cell death, suggesting that autophagy is a resistance mechanism in RMS cells exposed to proteotoxic drugs. However, combination treatment also causes caspase-dependent apoptosis, PARP cleavage and Annexin V staining, as simultaneous inhibition of both UPS and HSR systems limits cytoprotective autophagy, exacerbating stress resulting from accumulation of misfolded proteins. Conclusion The combination of proteasome inhibitor Bortezomib with Hsp90 inhibitor 17-DMAG, appears to have important therapeutic advantages in the treatment of RMS cells compared with single-agent exposure, because compensatory survival mechanisms that occur as side effects of treatment may be prevented.

  20. Metalloproteases Affecting Blood Coagulation, Fibrinolysis and Platelet Aggregation from Snake Venoms: Definition and Nomenclature of Interaction Sites

    Science.gov (United States)

    Kini, R. Manjunatha; Koh, Cho Yeow

    2016-01-01

    Snake venom metalloproteases, in addition to their contribution to the digestion of the prey, affect various physiological functions by cleaving specific proteins. They exhibit their activities through activation of zymogens of coagulation factors, and precursors of integrins or receptors. Based on their structure–function relationships and mechanism of action, we have defined classification and nomenclature of functional sites of proteases. These metalloproteases are useful as research tools and in diagnosis and treatment of various thrombotic and hemostatic conditions. They also contribute to our understanding of molecular details in the activation of specific factors involved in coagulation, platelet aggregation and matrix biology. This review provides a ready reference for metalloproteases that interfere in blood coagulation, fibrinolysis and platelet aggregation. PMID:27690102