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Sample records for prp chaperoning activities

  1. Propionate catabolism in Salmonella typhimurium LT2: two divergently transcribed units comprise the prp locus at 8.5 centisomes, prpR encodes a member of the sigma-54 family of activators, and the prpBCDE genes constitute an operon.

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    Horswill, A R; Escalante-Semerena, J C

    1997-02-01

    We present the initial genetic and biochemical characterization of the propionate (prp) locus at 8.5 centisomes of the Salmonella typhimurium LT2 chromosome (T. A. Hammelman et al., FEMS Microbiol. Lett. 137: 233-239, 1996). In this paper, we report the nucleotide sequences of two divergently transcribed transcriptional units. One unit is comprised of the prpR gene (1,626 bp) encoding a member of the sigma-54 family of transcriptional activators; the second unit contains an operon of four genes designated prpB (888 bp), prpC (1,170 bp), prpD (1,452 bp), and prpE (1,923 bp). The heme biosynthetic gene hemB was shown by DNA sequencing to be located immediately downstream of the prpBCDE operon; hemB is divergently transcribed from prpBCDE and is separated from prpE by a 66-bp gap. In addition, we demonstrate the involvement of PrpB, PrpC, and PrpD in propionate catabolism by complementation analysis of mutants using plasmids carrying a single prp gene under the control of the arabinose-responsive P(BAD) promoter. Expression of prpB to high levels was deleterious to the growth of a prp+ strain on minimal medium supplemented with propionate as a carbon and energy source. We also report the cloning and overexpression of prpB, prpC, prpD, and prpE in the T7 system. PrpB, PrpC, PrpD, and PrpE had molecular masses of ca. 32, ca. 44, ca. 53, and ca. 70 kDa, respectively. PrpB showed homology to carboxyphosphonoenolpyruvate phosphonomutase of Streptomyces hygroscopicus and to its homolog in the carnation Dianthus caryophyllus; PrpC was homologous to both archaeal and bacterial citrate synthases; PrpD showed homology to yeast and Bacillus subtilis proteins of unknown function; PrpE showed homology to acetyl coenzyme A synthetases. We identified a sigma-54 (RpoN)-dependent promoter with a consensus RpoN binding site upstream of the initiating methionine codon of prpB, the promoter-proximal gene of the prp operon. Consistent with this finding, an rpoN prp+ mutant failed to use

  2. The telomerase inhibitor Gno1p/PINX1 activates the helicase Prp43p during ribosome biogenesis.

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    Chen, Yan-Ling; Capeyrou, Régine; Humbert, Odile; Mouffok, Saïda; Kadri, Yasmine Al; Lebaron, Simon; Henras, Anthony K; Henry, Yves

    2014-06-01

    We provide evidence that a central player in ribosome synthesis, the ribonucleic acid helicase Prp43p, can be activated by yeast Gno1p and its human ortholog, the telomerase inhibitor PINX1. Gno1p and PINX1 expressed in yeast interact with Prp43p and the integrity of their G-patch domain is required for this interaction. Moreover, PINX1 interacts with human PRP43 (DHX15) in HeLa cells. PINX1 directly binds to yeast Prp43p and stimulates its adenosine triphosphatase activity, while alterations of the G patch abolish formation of the PINX1/Prp43p complex and the stimulation of Prp43p. In yeast, lack of Gno1p leads to a decrease in the levels of pre-40S and intermediate pre-60S pre-ribosomal particles, defects that can be corrected by PINX1 expression. We show that Gno1p associates with 90S and early pre-60S pre-ribosomal particles and is released from intermediate pre-60S particles. G-patch alterations in Gno1p or PINX1 that inhibit their interactions with Prp43p completely abolish their function in yeast ribosome biogenesis. Altogether, our results suggest that activation of Prp43p by Gno1p/PINX1 within early pre-ribosomal particles is crucial for their subsequent maturation. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. Transcription elongation factor GreA has functional chaperone activity.

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    Kun Li

    Full Text Available BACKGROUND: Bacterial GreA is an indispensable factor in the RNA polymerase elongation complex. It plays multiple roles in transcriptional elongation, and may be implicated in resistance to various stresses. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we show that Escherichia coli GreA inhibits aggregation of several substrate proteins under heat shock condition. GreA can also effectively promote the refolding of denatured proteins. These facts reveal that GreA has chaperone activity. Distinct from many molecular chaperones, GreA does not form stable complexes with unfolded substrates. GreA overexpression confers the host cells with enhanced resistance to heat shock and oxidative stress. Moreover, GreA expression in the greA/greB double mutant could suppress the temperature-sensitive phenotype, and dramatically alleviate the in vivo protein aggregation. The results suggest that bacterial GreA may act as chaperone in vivo. CONCLUSIONS/SIGNIFICANCE: These results suggest that GreA, in addition to its function as a transcription factor, is involved in protection of cellular proteins against aggregation.

  4. Humanin is an endogenous activator of chaperone-mediated autophagy.

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    Gong, Zhenwei; Tasset, Inmaculada; Diaz, Antonio; Anguiano, Jaime; Tas, Emir; Cui, Lingguang; Kuliawat, Regina; Liu, Honghai; Kühn, Bernhard; Cuervo, Ana Maria; Muzumdar, Radhika

    2017-11-29

    Chaperone-mediated autophagy (CMA) serves as quality control during stress conditions through selective degradation of cytosolic proteins in lysosomes. Humanin (HN) is a mitochondria-associated peptide that offers cytoprotective, cardioprotective, and neuroprotective effects in vivo and in vitro. In this study, we demonstrate that HN directly activates CMA by increasing substrate binding and translocation into lysosomes. The potent HN analogue HNG protects from stressor-induced cell death in fibroblasts, cardiomyoblasts, neuronal cells, and primary cardiomyocytes. The protective effects are lost in CMA-deficient cells, suggesting that they are mediated through the activation of CMA. We identified that a fraction of endogenous HN is present at the cytosolic side of the lysosomal membrane, where it interacts with heat shock protein 90 (HSP90) and stabilizes binding of this chaperone to CMA substrates as they bind to the membrane. Inhibition of HSP90 blocks the effect of HNG on substrate translocation and abolishes the cytoprotective effects. Our study provides a novel mechanism by which HN exerts its cardioprotective and neuroprotective effects. © 2018 Gong et al.

  5. Chaperone therapy for neuronopathic lysosomal diseases: competitive inhibitors as chemical chaperones for enhancement of mutant enzyme activities.

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    Suzuki, Yoshiyuki; Ogawa, Seiichiro; Sakakibara, Yasubumi

    2009-05-26

    Chaperone therapy is a newly developed molecular approach to lysosomal diseases, a group of human genetic diseases causing severe brain damage. We found two valienamine derivatives, N-octyl-4-epi-beta-valienamine (NOEV) and N-octyl-beta-valienamine (NOV), as promising therapeutic agents for human beta-galactosidase deficiency disorders (mainly G(M1)-gangliosidosis) and beta-glucosidase deficiency disorders (Gaucher disease), respectively. We briefly reviewed the historical background of research in carbasugar glycosidase inhibitors. Originally NOEV and NOV had been discovered as competitive inhibitors, and then their paradoxical bioactivities as chaperones were confirmed in cultured fibroblasts from patients with these disorders. Subsequently G(M1)-gangliosidosis model mice were developed and useful for experimental studies. Orally administered NOEV entered the brain through the blood-brain barrier, enhanced beta-galactosidase activity, reduced substrate storage, and improved neurological deterioration clinically. Furthermore, we executed computational analysis for prediction of molecular interactions between beta-galactosidase and NOEV. Some preliminary results of computational analysis of molecular interaction mechanism are presented in this article. NOV also showed the chaperone effect toward several beta-glucosidase gene mutations in Gaucher disease. We hope chaperone therapy will become available for some patients with G(M1)-gangliosidosis, Gaucher disease, and potentially other lysosomal storage diseases with central nervous system involvement.

  6. Evaluation of Not-Activated and Activated PRP in Hair Loss Treatment: Role of Growth Factor and Cytokine Concentrations Obtained by Different Collection Systems.

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    Gentile, Pietro; Cole, John P; Cole, Megan A; Garcovich, Simone; Bielli, Alessandra; Scioli, Maria Giovanna; Orlandi, Augusto; Insalaco, Chiara; Cervelli, Valerio

    2017-02-14

    Platelet rich plasma (PRP) was tested as a potential therapy for androgenetic alopecia (AGA) through two different clinical protocols in which one population (18 participants) received half-head treatment with autologous non-activated PRP (A-PRP) produced by CPunT Preparation System (Biomed Device, Modena, Italy) and the other half-head with placebo, and a second separated population in which all participants (n = 6, 3 participants per group) received treatment with calcium-activated PRP (AA-PRP) produced from one of two different PRP collection devices (Regen Blood Cell Therapy or Arthrex Angel System). For the A-PRP study, three treatments were administered over 30-day intervals. Trichoscan analysis of patients, three months post-treatment, showed a clinical improvement in the number of hairs in the target area (36 ± 3 hairs) and in total hair density (65±  5 hair cm2), whereas negligible improvements in hair count (1.1±  1.4 hairs) and density (1.9 ± 10.2 hair cm2) were seen in the region of the scalp that received placebo. Microscopic evaluation conducted two weeks after treatment showed also an increase in epidermal thickness, Ki67+ keratinocytes, and in the number of follicles. The AA-PRP treatment groups received a singular set of injections, and six months after the treatments were administered, notable differences in clinical outcomes were obtained from the two PRP collection devices (+90 ± 6 hair cm2 versus -73 ± 30 hair cm2 hair densities, Regen versus Arthrex). Growth factor concentrations in AA-PRP prepared from the two collection devices did not differ significantly upon calcium activation.

  7. Evaluation of Not-Activated and Activated PRP in Hair Loss Treatment: Role of Growth Factor and Cytokine Concentrations Obtained by Different Collection Systems

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    Pietro Gentile

    2017-02-01

    Full Text Available Platelet rich plasma (PRP was tested as a potential therapy for androgenetic alopecia (AGA through two different clinical protocols in which one population (18 participants received half-head treatment with autologous non-activated PRP (A-PRP produced by CPunT Preparation System (Biomed Device, Modena, Italy and the other half-head with placebo, and a second separated population in which all participants (n = 6, 3 participants per group received treatment with calcium-activated PRP (AA-PRP produced from one of two different PRP collection devices (Regen Blood Cell Therapy or Arthrex Angel System. For the A-PRP study, three treatments were administered over 30-day intervals. Trichoscan analysis of patients, three months post-treatment, showed a clinical improvement in the number of hairs in the target area (36 ± 3 hairs and in total hair density (65±  5 hair cm2, whereas negligible improvements in hair count (1.1±  1.4 hairs and density (1.9 ± 10.2 hair cm2 were seen in the region of the scalp that received placebo. Microscopic evaluation conducted two weeks after treatment showed also an increase in epidermal thickness, Ki67+ keratinocytes, and in the number of follicles. The AA-PRP treatment groups received a singular set of injections, and six months after the treatments were administered, notable differences in clinical outcomes were obtained from the two PRP collection devices (+90 ± 6 hair cm2 versus -73 ± 30 hair cm2 hair densities, Regen versus Arthrex. Growth factor concentrations in AA-PRP prepared from the two collection devices did not differ significantly upon calcium activation.

  8. The Chaperone Activity of Clusterin is Dependent on Glycosylation and Redox Environment

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    Philipp Rohne

    2014-11-01

    Full Text Available Background/Aims: Clusterin (CLU, also known as Apolipoprotein J (ApoJ is a highly glycosylated extracellular chaperone. In humans it is expressed from a broad spectrum of tissues and related to a plethora of physiological and pathophysiological processes, such as Alzheimer's disease, atherosclerosis and cancer. In its dominant form it is expressed as a secretory protein (secreted CLU, sCLU. During its maturation, the sCLU-precursor is N-glycosylated and cleaved into an α- and a β-chain, which are connected by five symmetrical disulfide bonds. Recently, it has been demonstrated that besides the predominant sCLU, rare intracellular CLU forms are expressed in stressed cells. Since these forms do not enter or complete the secretory pathway, they are not proteolytically modified and show either no or only core glycosylation. Due to their sparsity, these intracellular forms are functionally poorly characterized. To evaluate the function(s of these stress-related intracellular forms, we investigate for the first time the impact of proteolytic cleavage, differential glycosylation and the influence of the redox environment on the chaperone activity of CLU. Methods: Non-cleavable sCLU was generated by expression from a mutant construct of sCLU, in which the furin-like proprotein convertase (PC recognition site was modified. After purification of recombinant uncleaved sCLU from the medium of over-expressing cells, we performed chaperone activity assays to compare the activities of wild-type (cleaved and uncleaved mutant sCLU. Additionally, this approach enabled us to investigate the role of carbohydrates, the proteolytic maturation and reducing conditions on CLU chaperone activity. Further, we characterized the differentially treated CLU forms by using MALDI-TOF, CD-spectroscopy and Western blotting in addition to the functional assay. Results: We show that the PC-cleavage is dispensable for sCLU chaperone activity. Moreover, our data demonstrate that

  9. Conserved TRAM Domain Functions as an Archaeal Cold Shock Protein via RNA Chaperone Activity

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    Bo Zhang

    2017-08-01

    Full Text Available Cold shock proteins (Csps enable organisms to acclimate to and survive in cold environments and the bacterial CspA family exerts the cold protection via its RNA chaperone activity. However, most Archaea do not contain orthologs to the bacterial csp. TRAM, a conserved domain among RNA modification proteins ubiquitously distributed in organisms, occurs as an individual protein in most archaeal phyla and has a structural similarity to Csp proteins, yet its biological functions remain unknown. Through physiological and biochemical studies on four TRAM proteins from a cold adaptive archaeon Methanolobus psychrophilus R15, this work demonstrated that TRAM is an archaeal Csp and exhibits RNA chaperone activity. Three TRAM encoding genes (Mpsy_0643, Mpsy_3043, and Mpsy_3066 exhibited remarkable cold-shock induced transcription and were preferentially translated at lower temperature (18°C, while the fourth (Mpsy_2002 was constitutively expressed. They were all able to complement the cspABGE mutant of Escherichia coli BX04 that does not grow in cold temperatures and showed transcriptional antitermination. TRAM3066 (gene product of Mpsy_3066 and TRAM2002 (gene product of Mpsy_2002 displayed sequence-non-specific RNA but not DNA binding activity, and TRAM3066 assisted RNases in degradation of structured RNA, thus validating the RNA chaperone activity of TRAMs. Given the chaperone activity, TRAM is predicted to function beyond a Csp.

  10. The chaperone activity and toxicity of ambroxol on Gaucher cells and normal mice.

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    Luan, Zhuo; Li, Linjing; Higaki, Katsumi; Nanba, Eiji; Suzuki, Yoshiyuki; Ohno, Kousaku

    2013-04-01

    Gaucher disease (GD), caused by a defect of acid β-glucosidase (β-Glu), is one of the most common sphingolipidoses. Recently, ambroxol, an FDA-approved drug used to treat airway mucus hypersecretion and hyaline membrane disease in newborns, was identified as a chemical chaperone for GD. In the present study, we investigated the chaperone activity and toxicity of ambroxol on both cultured GD patient cells and normal mice. We found that ambroxol treatment significantly increased N370S, F213I, N188S/G193W and R120W mutant β-Glu activities in GD fibroblasts with low cytotoxicity. Additionally, we measured the β-Glu activity in the tissues of normal mice which received water containing increasing concentrations of ambroxol ad libitum for one week. No serious adverse effect was observed during this experiment. Ambroxol significantly increased the β-Glu activity in the spleen, heart and cerebellum of the mice. This result showed its oral availability and wide distribution and chaperone activity in the tissues, including the brain, and its lack of acute toxicity. These characteristics of ambroxol would make it a potential therapeutic chaperone in the treatment of GD with neurological manifestations. Copyright © 2012 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  11. Dynamic Contacts of U2, RES, Cwc25, Prp8 and Prp45 Proteins with the Pre-mRNA Branch-Site and 3' Splice Site during Catalytic Activation and Step 1 Catalysis in Yeast Spliceosomes.

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    Cornelius Schneider

    Full Text Available Little is known about contacts in the spliceosome between proteins and intron nucleotides surrounding the pre-mRNA branch-site and their dynamics during splicing. We investigated protein-pre-mRNA interactions by UV-induced crosslinking of purified yeast B(act spliceosomes formed on site-specifically labeled pre-mRNA, and analyzed their changes after conversion to catalytically-activated B* and step 1 C complexes, using a purified splicing system. Contacts between nucleotides upstream and downstream of the branch-site and the U2 SF3a/b proteins Prp9, Prp11, Hsh49, Cus1 and Hsh155 were detected, demonstrating that these interactions are evolutionarily conserved. The RES proteins Pml1 and Bud13 were shown to contact the intron downstream of the branch-site. A comparison of the B(act crosslinking pattern versus that of B* and C complexes revealed that U2 and RES protein interactions with the intron are dynamic. Upon step 1 catalysis, Cwc25 contacts with the branch-site region, and enhanced crosslinks of Prp8 and Prp45 with nucleotides surrounding the branch-site were observed. Cwc25's step 1 promoting activity was not dependent on its interaction with pre-mRNA, indicating it acts via protein-protein interactions. These studies provide important insights into the spliceosome's protein-pre-mRNA network and reveal novel RNP remodeling events during the catalytic activation of the spliceosome and step 1 of splicing.

  12. LINE-1 retrotransposition requires the nucleic acid chaperone activity of the ORF1 protein.

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    Martin, Sandra L; Cruceanu, Margareta; Branciforte, Dan; Wai-Lun Li, Patrick; Kwok, Stanley C; Hodges, Robert S; Williams, Mark C

    2005-05-06

    LINE-1 is a highly successful, non-LTR retrotransposon that has played a leading role in shaping mammalian genomes. These elements move autonomously through an RNA intermediate using target-primed reverse transcription (TPRT). L1 encodes two essential polypeptides for retrotransposition, the products of its two open reading frames, ORF1 and ORF2. The exact function of the ORF1 protein (ORF1p) in L1 retrotransposition is unknown, although it is an RNA-binding protein that can act as a nucleic acid chaperone. Here, we investigate the requirements for these two activities in L1 retrotransposition by examining the consequences of mutating two adjacent and highly conserved arginine residues in the ORF1p from mouse L1. Substitution of both arginine residues with alanine strongly reduces the affinity of the protein for single-stranded nucleic acid, whereas substitution of one or both with lysine has only minimal effects on this feature. Rather, the lysine substitutions alter the delicate balance between the ORF1 protein's melting and reannealing activities, thereby reducing its nucleic acid chaperone activity. These findings establish the importance of the nucleic acid chaperone activity of ORF1p to successful L1 retrotransposition, and provide insight into the essential properties of nucleic acid chaperones.

  13. Conformational changes in human Hsp70 induced by high hydrostatic pressure produce oligomers with ATPase activity but without chaperone activity.

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    Araujo, Thaís L S; Borges, Julio Cesar; Ramos, Carlos H; Meyer-Fernandes, José Roberto; Oliveira Júnior, Reinaldo S; Pascutti, Pedro G; Foguel, Debora; Palhano, Fernando L

    2014-05-13

    We investigated the folding of the 70 kDa human cytosolic inducible protein (Hsp70) in vitro using high hydrostatic pressure as a denaturing agent. We followed the structural changes in Hsp70 induced by high hydrostatic pressure using tryptophan fluorescence, molecular dynamics, circular dichroism, high-performance liquid chromatography gel filtration, dynamic light scattering, ATPase activity, and chaperone activity. Although monomeric, Hsp70 is very sensitive to hydrostatic pressure; after pressure had been removed, the protein did not return to its native sate but instead formed oligomeric species that lost chaperone activity but retained ATPase activity.

  14. The Healing Effects of Aquatic Activities and Allogenic Injection of Platelet-Rich Plasma (PRP) on Injuries of Achilles Tendon in Experimental Rat.

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    Rajabi, Hamid; Sheikhani Shahin, Homa; Norouzian, Manijeh; Mehrabani, Davood; Dehghani Nazhvani, Seifollah

    2015-01-01

    Clinical tendon injuries represent serious and unresolved issues of the case on how the injured tendons could be improved based on natural structure and mechanical strength. The aim of this studies the effect of aquatic activities and alogenic platelet rich plasma (PRP) injection in healing Achilles tendons of rats. Forty rats were randomly divided into 5 equal groups. Seventy two hours after a crush lesion on Achilles tendon, group 1 underwent aquatic activity for 8 weeks (five sessions per week), group 2 received intra-articular PRP (1 ml), group 3 had aquatic activity together with injection PRP injection after an experimental tendon injury, group 4 did not receive any treatment after tendon injury and the control group with no tendon injuries. of 32 rats. After 8 weeks, the animals were sacrificed and the tendons were transferred in 10% formalin for histological evaluation. There was a significant increase in number of fibroblast and cellular density, and collagen deposition in group 3 comparing to other groups denoting to an effective healing in injured tendons. However, there was no significant difference among the studied groups based on their tendons diameter. Based on our findings on the number of fibroblast, cellular density, collagen deposition, and tendon diameter, it was shown that aquatic activity together with PRP injection was the therapeutic measure of choice enhance healing in tendon injuries that can open a window in treatment of damages to tendons.

  15. Contributions of chaperone and glycosyltransferase activities of O-fucosyltransferase 1 to Notch signaling

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    Irvine Kenneth D

    2008-01-01

    Full Text Available Abstract Background O-fucosyltransferase1 (OFUT1 is a conserved ER protein essential for Notch signaling. OFUT1 glycosylates EGF domains, which can then be further modified by the N-acetylglucosaminyltransferase Fringe. OFUT1 also possesses a chaperone activity that promotes the folding and secretion of Notch. Here, we investigate the respective contributions of these activities to Notch signaling in Drosophila. Results We show that expression of an isoform lacking fucosyltransferase activity, Ofut1R245A, rescues the requirement for Ofut1 in embryonic neurogenesis. Lack of requirement for O-fucosylation is further supported by the absence of embryonic phenotypes in Gmd mutants, which lack all forms of fucosylation. Requirements for O-fucose during imaginal development were evaluated by characterizing clones of cells expressing only Ofut1R245A. These clones phenocopy fringe mutant clones, indicating that the absence of O-fucose is functionally equivalent to the absence of elongated O-fucose. Conclusion Our results establish that Notch does not need to be O-fucosylated for fringe-independent Notch signaling in Drosophila; the chaperone activity of OFUT1 is sufficient for the generation of functional Notch.

  16. Human protein-disulfide isomerase is a redox-regulated chaperone activated by oxidation of domain a'.

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    Wang, Chao; Yu, Jiang; Huo, Lin; Wang, Lei; Feng, Wei; Wang, Chih-chen

    2012-01-06

    Protein-disulfide isomerase (PDI), with domains arranged as abb'xa'c, is a key enzyme and chaperone localized in the endoplasmic reticulum (ER) catalyzing oxidative folding and preventing misfolding/aggregation of proteins. It has been controversial whether the chaperone activity of PDI is redox-regulated, and the molecular basis is unclear. Here, we show that both the chaperone activity and the overall conformation of human PDI are redox-regulated. We further demonstrate that the conformational changes are triggered by the active site of domain a', and the minimum redox-regulated cassette is located in b'xa'. The structure of the reduced bb'xa' reveals for the first time that domain a' packs tightly with both domain b' and linker x to form one compact structural module. Oxidation of domain a' releases the compact conformation and exposes the shielded hydrophobic areas to facilitate its high chaperone activity. Thus, the study unequivocally provides mechanistic insights into the redox-regulated chaperone activity of human PDI.

  17. Human Protein-disulfide Isomerase Is a Redox-regulated Chaperone Activated by Oxidation of Domain a′*

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    Wang, Chao; Yu, Jiang; Huo, Lin; Wang, Lei; Feng, Wei; Wang, Chih-chen

    2012-01-01

    Protein-disulfide isomerase (PDI), with domains arranged as abb′xa′c, is a key enzyme and chaperone localized in the endoplasmic reticulum (ER) catalyzing oxidative folding and preventing misfolding/aggregation of proteins. It has been controversial whether the chaperone activity of PDI is redox-regulated, and the molecular basis is unclear. Here, we show that both the chaperone activity and the overall conformation of human PDI are redox-regulated. We further demonstrate that the conformational changes are triggered by the active site of domain a′, and the minimum redox-regulated cassette is located in b′xa′. The structure of the reduced bb′xa′ reveals for the first time that domain a′ packs tightly with both domain b′ and linker x to form one compact structural module. Oxidation of domain a′ releases the compact conformation and exposes the shielded hydrophobic areas to facilitate its high chaperone activity. Thus, the study unequivocally provides mechanistic insights into the redox-regulated chaperone activity of human PDI. PMID:22090031

  18. Acid-denatured Green Fluorescent Protein (GFP) as model substrate to study the chaperone activity of protein disulfide isomerase.

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    Mares, Rosa E; Meléndez-López, Samuel G; Ramos, Marco A

    2011-01-01

    Green fluorescent protein (GFP) has been widely used in several molecular and cellular biology applications, since it is remarkably stable in vitro and in vivo. Interestingly, native GFP is resistant to the most common chemical denaturants; however, a low fluorescence signal has been observed after acid-induced denaturation. Furthermore, this acid-denatured GFP has been used as substrate in studies of the folding activity of some bacterial chaperones and other chaperone-like molecules. Protein disulfide isomerase enzymes, a family of eukaryotic oxidoreductases that catalyze the oxidation and isomerization of disulfide bonds in nascent polypeptides, play a key role in protein folding and it could display chaperone activity. However, contrasting results have been reported using different proteins as model substrates. Here, we report the further application of GFP as a model substrate to study the chaperone activity of protein disulfide isomerase (PDI) enzymes. Since refolding of acid-denatured GFP can be easily and directly monitored, a simple micro-assay was used to study the effect of the molecular participants in protein refolding assisted by PDI. Additionally, the effect of a well-known inhibitor of PDI chaperone activity was also analyzed. Because of the diversity their functional activities, PDI enzymes are potentially interesting drug targets. Since PDI may be implicated in the protection of cells against ER stress, including cancer cells, inhibitors of PDI might be able to enhance the efficacy of cancer chemotherapy; furthermore, it has been demonstrated that blocking the reductive cleavage of disulfide bonds of proteins associated with the cell surface markedly reduces the infectivity of the human immunodeficiency virus. Although several high-throughput screening (HTS) assays to test PDI reductase activity have been described, we report here a novel and simple micro-assay to test the chaperone activity of PDI enzymes, which is amenable for HTS of PDI

  19. A 21-kDa C-terminal fragment of protein-disulfide isomerase has isomerase, chaperone, and anti-chaperone activities.

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    Puig, A; Primm, T P; Surendran, R; Lee, J C; Ballard, K D; Orkiszewski, R S; Makarov, V; Gilbert, H F

    1997-12-26

    A catalyst of disulfide formation and isomerization during protein folding, protein-disulfide isomerase (PDI) has two catalytic sites housed in two domains homologous to thioredoxin, one near the N terminus and the other near the C terminus. The thioredoxin domains, by themselves, can catalyze disulfide formation, but they are unable to catalyze disulfide isomerizations (Darby, N. J. and Creighton, T. E. (1995) Biochemistry 34, 11725-11735). A 21-kDa, C-terminal fragment of PDI (amino acids 308-491), termed weePDI, comprises the C-terminal third of the molecule. The kcat for ribonuclease oxidative folding by weePDI is 0.26 +/- 0.02 min-1, 3-fold lower than the wild-type enzyme but indistinguishable from the activity of a full-length mutant of PDI in which both active site cysteines of the N-terminal thioredoxin domain have been mutated to serine. Eliminating the ability of weePDI to escape easily from covalent complexes with substrate by mutating the active site cysteine nearer the C terminus to serine has a large effect on the isomerase activity of weePDI compared with its effect on the full-length enzyme. weePDI also displays chaperone and anti-chaperone activity characteristic of the full-length molecule. As isolated, weePDI is a disulfide-linked dimer in which the single cysteine (Cys-326) outside active site cross-links two weePDI monomers. The presence of the intermolecular disulfide decreases the activity by more than 2-fold. The results imply that the functions of the core thioredoxin domains of PDI and other members of the thioredoxin superfamily might be modified quite easily by the addition of relatively small accessory domains.

  20. Delay of diabetic cataract in rats by the antiglycating potential of cumin through modulation of alpha-crystallin chaperone activity.

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    Kumar, Pasupulati Anil; Reddy, Paduru Yadagiri; Srinivas, P N B S; Reddy, Geereddy Bhanuprakash

    2009-07-01

    alpha-Crystallin, a molecular chaperone of the eye lens, plays an important role in maintaining the transparency of the lens by preventing the aggregation/inactivation of several proteins and enzymes in addition to its structural role. alpha-Crystallin is a long-lived protein and is susceptible to several posttranslational modifications during aging, more so in certain clinical conditions such as diabetes. Nonenzymatic glycation of lens proteins and decline in the chaperone-like function of alpha-crystallin have been reported in diabetic conditions. Therefore, inhibitors of nonenzymatic protein glycation appear to be a potential target to preserve the chaperone activity of alpha-crystallin and to combat cataract under hyperglycemic conditions. In this study, we investigated the antiglycating potential of cumin in vitro and its ability to modulate the chaperone-like activity of alpha-crystallin vis-à-vis the progression of diabetic cataract in vivo. Aqueous extract of cumin was tested for its antiglycating ability against fructose-induced glycation of goat lens total soluble protein (TSP), alpha-crystallin from goat lens and a nonlenticular protein bovine serum albumin (BSA). The antiglycating potential of cumin was also investigated by feeding streptozotocin (STZ)-induced diabetic rats with diet containing 0.5% cumin powder. The aqueous extract of cumin prevented in vitro glycation of TSP, alpha-crystallin and BSA. Slit lamp examination revealed that supplementation of cumin delayed progression and maturation of STZ-induced cataract in rats. Cumin was effective in preventing glycation of TSP and alpha-crystallin in diabetic lens. Interestingly, feeding of cumin to diabetic rats not only prevented loss of chaperone activity but also attenuated the structural changes of alpha-crystallin in lens. These results indicated that cumin has antiglycating properties that may be attributed to the modulation of chaperone activity of alpha-crystallin, thus delaying cataract in

  1. Chaperone-Like Activity of ß-Casein and Its Effect on Residual in Vitro Activity of Food Enzymes

    DEFF Research Database (Denmark)

    Sulewska, Anna Maria

    Agaricus bisporus and equine cytochrome c. Only for the first target β-casein was acting as a molecular chaperone i.e. its presence resulted in higher residual activity (higher degree of the function preservation). β-Casein did not have any influence on the residual activity of tyrosinase. Surprisingly....... The negative effect of BSA on enzyme was not observed before. The residual activity of horseradish peroxidase was also improved by the reconstituted skim milk: addition of reconstituted skim milk prior to heat treatment resulted in higher residual activity of HRP compared to no addition (58±3% and 30...

  2. A Chaperone Enhances Blood α-Glucosidase Activity in Pompe Disease Patients Treated With Enzyme Replacement Therapy

    Science.gov (United States)

    Parenti, Giancarlo; Fecarotta, Simona; la Marca, Giancarlo; Rossi, Barbara; Ascione, Serena; Donati, Maria Alice; Morandi, Lucia Ovidia; Ravaglia, Sabrina; Pichiecchio, Anna; Ombrone, Daniela; Sacchini, Michele; Pasanisi, Maria Barbara; De Filippi, Paola; Danesino, Cesare; Della Casa, Roberto; Romano, Alfonso; Mollica, Carmine; Rosa, Margherita; Agovino, Teresa; Nusco, Edoardo; Porto, Caterina; Andria, Generoso

    2014-01-01

    Enzyme replacement therapy is currently the only approved treatment for Pompe disease, due to acid α-glucosidase deficiency. Clinical efficacy of this approach is variable, and more effective therapies are needed. We showed in preclinical studies that chaperones stabilize the recombinant enzyme used for enzyme replacement therapy. Here, we evaluated the effects of a combination of enzyme therapy and a chaperone on α-glucosidase activity in Pompe disease patients. α-Glucosidase activity was analyzed by tandem-mass spectrometry in dried blood spots from patients treated with enzyme replacement therapy, either alone or in combination with the chaperone N-butyldeoxynojirimycin given at the time of the enzyme infusion. Thirteen patients with different presentations (3 infantile-onset, 10 late-onset) were enrolled. In 11 patients, the combination treatment resulted in α-glucosidase activities greater than 1.85-fold the activities with enzyme replacement therapy alone. In the whole patient population, α-glucosidase activity was significantly increased at 12 hours (2.19-fold, P = 0.002), 24 hours (6.07-fold, P = 0.001), and 36 hours (3.95-fold, P = 0.003). The areas under the curve were also significantly increased (6.78-fold, P = 0.002). These results suggest improved stability of recombinant α-glucosidase in blood in the presence of the chaperone. PMID:25052852

  3. A DNAJB Chaperone Subfamily with HDAC-Dependent Activities Suppresses Toxic Protein Aggregation

    NARCIS (Netherlands)

    Hageman, Jurre; Rujano, Maria A.; van Waarde, Maria A. W. H.; Kakkar, Vaishali; Dirks, Ron P.; Govorukhina, Natalia; Oosterveld-Hut, Henderika M. J.; Lubsen, Nicolette H.; Kampinga, Harm H.

    2010-01-01

    Misfolding and aggregation are associated with cytotoxicity in several protein folding diseases. A large network of molecular chaperones ensures protein quality control. Here, we show that within the Hsp70, Hsp110, and Hsp40 (DNAJ) chaperone families, members of a subclass of the DNAJB family

  4. Periodontal tissue regeneration with PRP incorporated gelatin hydrogel sponges.

    Science.gov (United States)

    Nakajima, Dai; Tabata, Yasuhiko; Sato, Soh

    2015-10-20

    Gelatin hydrogels have been designed and prepared for the controlled release of the transforming growth factor (TGF-b1) and the platelet-derived growth factor (PDGF-BB). PRP (Platelet rich plasma) contains many growth factors including the PDGF and TGF-b1. The objective of this study was to evaluate the regeneration of periodontal tissue following the controlled release of growth factors in PRP. For the periodontal ligament cells and osteoblast, PRP of different concentrations was added. The assessment of DNA, mitochondrial activity and ALP activity were measured. To evaluate the TGF-β1 release from PRP incorporated gelatin sponge, amounts of TGF-β1 in each supernatant sample were determined by the ELISA. Transplantation experiments to prepare a bone defect in a rat alveolar bone were an implanted gelatin sponge incorporated with different concentration PRP. In DNA assay and MTT assay, after the addition of PRP to the periodontal ligament cells and osteoblast, the cell count and mitochondrial activity had increased the most in the group with the addition of 5  ×  PRP. In the ALP assay, after the addition of PRP to the periodontal ligament cells, the cell activity had increased the most in the group with the addition of 3  ×  PRP. In the transplantation, the size of the bone regenerated in the defect with 3  ×  PRP incorporated gelatin sponge was larger than that of the other group.

  5. Different contributions of HtrA protease and chaperone activities to Campylobacter jejuni stress tolerance and physiology

    DEFF Research Database (Denmark)

    Bæk, Kristoffer Torbjørn; Vegge, Christina Skovgaard; Skórko-Glonek, Joanna

    2011-01-01

    activity is sufficient for growth at high temperature or oxidative stress, whereas the HtrA protease activity is only essential at conditions close to the growth limit for C. jejuni. However, the protease activity was required to prevent induction of the cytoplasmic heat-shock response even at optimal......, but little is known about how each of these activities contributes to stress tolerance in bacteria. In vitro experiments showed temperature dependent protease and chaperone activities of C. jejuni HtrA. A C. jejuni mutant lacking only the protease activity of HtrA was used to show that the HtrA chaperone...... growth conditions. Interestingly, the requirement of HtrA at high temperatures was found to depend on the oxygen level and our data suggest that HtrA may protect oxidatively damaged proteins. Finally, protease activity stimulates HtrA production and oligomer formation, suggesting that a regulatory role...

  6. Functional Amyloid Protection in the Eye Lens: Retention of α-Crystallin Molecular Chaperone Activity after Modification into Amyloid Fibrils.

    Science.gov (United States)

    Garvey, Megan; Ecroyd, Heath; Ray, Nicholas J; Gerrard, Juliet A; Carver, John A

    2017-09-12

    Amyloid fibril formation occurs from a wide range of peptides and proteins and is typically associated with a loss of protein function and/or a gain of toxic function, as the native structure of the protein undergoes major alteration to form a cross β-sheet array. It is now well recognised that some amyloid fibrils have a biological function, which has led to increased interest in the potential that these so-called functional amyloids may either retain the function of the native protein, or gain function upon adopting a fibrillar structure. Herein, we investigate the molecular chaperone ability of α-crystallin, the predominant eye lens protein which is composed of two related subunits αA- and αB-crystallin, and its capacity to retain and even enhance its chaperone activity after forming aggregate structures under conditions of thermal and chemical stress. We demonstrate that both eye lens α-crystallin and αB-crystallin (which is also found extensively outside the lens) retain, to a significant degree, their molecular chaperone activity under conditions of structural change, including after formation into amyloid fibrils and amorphous aggregates. The results can be related directly to the effects of aging on the structure and chaperone function of α-crystallin in the eye lens, particularly its ability to prevent crystallin protein aggregation and hence lens opacification associated with cataract formation.

  7. Functional Amyloid Protection in the Eye Lens: Retention of α-Crystallin Molecular Chaperone Activity after Modification into Amyloid Fibrils

    Directory of Open Access Journals (Sweden)

    Megan Garvey

    2017-09-01

    Full Text Available Amyloid fibril formation occurs from a wide range of peptides and proteins and is typically associated with a loss of protein function and/or a gain of toxic function, as the native structure of the protein undergoes major alteration to form a cross β-sheet array. It is now well recognised that some amyloid fibrils have a biological function, which has led to increased interest in the potential that these so-called functional amyloids may either retain the function of the native protein, or gain function upon adopting a fibrillar structure. Herein, we investigate the molecular chaperone ability of α-crystallin, the predominant eye lens protein which is composed of two related subunits αA- and αB-crystallin, and its capacity to retain and even enhance its chaperone activity after forming aggregate structures under conditions of thermal and chemical stress. We demonstrate that both eye lens α-crystallin and αB-crystallin (which is also found extensively outside the lens retain, to a significant degree, their molecular chaperone activity under conditions of structural change, including after formation into amyloid fibrils and amorphous aggregates. The results can be related directly to the effects of aging on the structure and chaperone function of α-crystallin in the eye lens, particularly its ability to prevent crystallin protein aggregation and hence lens opacification associated with cataract formation.

  8. c-Abl Mediated Tyrosine Phosphorylation of Aha1 Activates Its Co-chaperone Function in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Diana M. Dunn

    2015-08-01

    Full Text Available The ability of Heat Shock Protein 90 (Hsp90 to hydrolyze ATP is essential for its chaperone function. The co-chaperone Aha1 stimulates Hsp90 ATPase activity, tailoring the chaperone function to specific “client” proteins. The intracellular signaling mechanisms directly regulating Aha1 association with Hsp90 remain unknown. Here, we show that c-Abl kinase phosphorylates Y223 in human Aha1 (hAha1, promoting its interaction with Hsp90. This, consequently, results in an increased Hsp90 ATPase activity, enhances Hsp90 interaction with kinase clients, and compromises the chaperoning of non-kinase clients such as glucocorticoid receptor and CFTR. Suggesting a regulatory paradigm, we also find that Y223 phosphorylation leads to ubiquitination and degradation of hAha1 in the proteasome. Finally, pharmacologic inhibition of c-Abl prevents hAha1 interaction with Hsp90, thereby hypersensitizing cancer cells to Hsp90 inhibitors both in vitro and ex vivo.

  9. The Effect of Autologous Activated Platelet Rich Plasma (AA-PRP Injection on Pattern Hair Loss: Clinical and Histomorphometric Evaluation

    Directory of Open Access Journals (Sweden)

    V. Cervelli

    2014-01-01

    Full Text Available To investigate the safety and clinical efficacy of AA-PRP injections for pattern hair loss. AA-PRP, prepared from a small volume of blood, was injected on half of the selected patients’ scalps with pattern hair loss. The other half was treated with placebo. Three treatments were given for each patient, with intervals of 1 month. The endpoints were hair re-growth, hair dystrophy as measured by dermoscopy, burning or itching sensation, and cell proliferation as measured by Ki-67 evaluation. At the end of the 3 cycles of treatment, the patients presented clinical improvement in the mean number of hairs, with a mean increase of 18.0 hairs in the target area, and a mean increase in total hair density of 27.7 ( number of hairs/cm2 compared with baseline values. Microscopic evaluation showed the increase of epidermis thickness and of the number of hair follicles two weeks after the last AA-PRP treatment compared to baseline value (P<0.05. We also observed an increase of Ki67+ keratinocytes of epidermis and of hair follicular bulge cells and a slight increase of small blood vessels around hair follicles in the treated skin compared to baseline (P<0.05.

  10. Structural features important for the RNA chaperone activity of zinc finger-containing glycine-rich RNA-binding proteins from wheat (Triticum avestivum) and rice (Oryza sativa).

    Science.gov (United States)

    Xu, Tao; Han, Ji Hoon; Kang, Hunseung

    2013-10-01

    Despite the increase in understanding of RNA chaperone activity of zinc finger-containing glycine-rich RNA-binding proteins (RZs) during the cold adaptation process, the structural features relevant to the RNA chaperone activity of RZs still largely remain to be established. To investigate the structural determinants important for the RNA chaperone activity of RZs, domain-swapping and deletion analyses was carried out to assess the contribution of the N-terminal zinc finger RNA-recognition motif (RRM) domain and the C-terminal glycine-rich region of wheat (Triticum avestivum) and rice (Oryza sativa) RZs to RNA chaperone activity. Although the amino acid sequence similarity among wheat TaRZ2, wheat TaRZ3, and rice OsRZ1 was high, only TaRZ2 had RNA chaperone activity as evidenced by complementation ability in cold-sensitive Escherichia coli mutant cell under cold stress and in vivo and in vitro nucleic acid-melting activity. Domain-swapping and deletion analysis demonstrated that the overall folding of RZs governed by the N-terminal RRM domain and the C-terminal glycine-rich region, as well as the size of the disordered C-terminal glycine-rich region, are crucial for the RNA chaperone activity of RZs. Collectively, these results indicate that a specific modular arrangement of RRM domain and the disordered C-terminal region determines the RNA chaperone activity of RZs in cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Chaperone-Like Activity of ß-Casein and Its Effect on Residual in Vitro Activity of Food Enzymes

    DEFF Research Database (Denmark)

    Sulewska, Anna Maria

    ABSTRACT Activity of endogenous enzymes may cause browning of fruits and vegetables. These enzymes can be inactivated, for example by heat treatment, but the response of enzymes to heat treatment depends on many factors. Foods are very complex systems and the stability of enzymes in such an envir......ABSTRACT Activity of endogenous enzymes may cause browning of fruits and vegetables. These enzymes can be inactivated, for example by heat treatment, but the response of enzymes to heat treatment depends on many factors. Foods are very complex systems and the stability of enzymes...... in such an environment can be influenced by other components of the system potentially leading to enhancement of unwanted reactions or reduction of wanted ones. Caseins can potentially enhance the stability of other food proteins, as they were shown to exhibit chaperone-like activity. In this study influence of β...... Agaricus bisporus and equine cytochrome c. Only for the first target β-casein was acting as a molecular chaperone i.e. its presence resulted in higher residual activity (higher degree of the function preservation). β-Casein did not have any influence on the residual activity of tyrosinase. Surprisingly...

  12. DJ-1 Is a Copper Chaperone Acting on SOD1 Activation*

    Science.gov (United States)

    Girotto, Stefania; Cendron, Laura; Bisaglia, Marco; Tessari, Isabella; Mammi, Stefano; Zanotti, Giuseppe; Bubacco, Luigi

    2014-01-01

    Lack of oxidative stress control is a common and often prime feature observed in many neurodegenerative diseases. Both DJ-1 and SOD1, proteins involved in familial Parkinson disease and amyotrophic lateral sclerosis, respectively, play a protective role against oxidative stress. Impaired activity and modified expression of both proteins have been observed in different neurodegenerative diseases. A potential cooperative action of DJ-1 and SOD1 in the same oxidative stress response pathway may be suggested based on a copper-mediated interaction between the two proteins reported here. To investigate the mechanisms underlying the antioxidative function of DJ-1 in relation to SOD1 activity, we investigated the ability of DJ-1 to bind copper ions. We structurally characterized a novel copper binding site involving Cys-106, and we investigated, using different techniques, the kinetics of DJ-1 binding to copper ions. The copper transfer between the two proteins was also examined using both fluorescence spectroscopy and specific biochemical assays for SOD1 activity. The structural and functional analysis of the novel DJ-1 copper binding site led us to identify a putative role for DJ-1 as a copper chaperone. Alteration of the coordination geometry of the copper ion in DJ-1 may be correlated to the physiological role of the protein, to a potential failure in metal transfer to SOD1, and to successive implications in neurodegenerative etiopathogenesis. PMID:24567322

  13. DJ-1 is a copper chaperone acting on SOD1 activation.

    Science.gov (United States)

    Girotto, Stefania; Cendron, Laura; Bisaglia, Marco; Tessari, Isabella; Mammi, Stefano; Zanotti, Giuseppe; Bubacco, Luigi

    2014-04-11

    Lack of oxidative stress control is a common and often prime feature observed in many neurodegenerative diseases. Both DJ-1 and SOD1, proteins involved in familial Parkinson disease and amyotrophic lateral sclerosis, respectively, play a protective role against oxidative stress. Impaired activity and modified expression of both proteins have been observed in different neurodegenerative diseases. A potential cooperative action of DJ-1 and SOD1 in the same oxidative stress response pathway may be suggested based on a copper-mediated interaction between the two proteins reported here. To investigate the mechanisms underlying the antioxidative function of DJ-1 in relation to SOD1 activity, we investigated the ability of DJ-1 to bind copper ions. We structurally characterized a novel copper binding site involving Cys-106, and we investigated, using different techniques, the kinetics of DJ-1 binding to copper ions. The copper transfer between the two proteins was also examined using both fluorescence spectroscopy and specific biochemical assays for SOD1 activity. The structural and functional analysis of the novel DJ-1 copper binding site led us to identify a putative role for DJ-1 as a copper chaperone. Alteration of the coordination geometry of the copper ion in DJ-1 may be correlated to the physiological role of the protein, to a potential failure in metal transfer to SOD1, and to successive implications in neurodegenerative etiopathogenesis.

  14. Activation of sigma-1 receptor chaperone in the treatment of neuropsychiatric diseases and its clinical implication

    Directory of Open Access Journals (Sweden)

    Kenji Hashimoto

    2015-01-01

    Full Text Available Endoplasmic reticulum (ER protein sigma-1 receptor represents unique chaperone activity in the central nervous system, and it exerts a potent influence on a number of neurotransmitter systems. Several lines of evidence suggest that activation of sigma-1 receptor plays a role in the pathophysiology of neuropsychiatric diseases, as well as in the mechanisms of some therapeutic drugs and neurosteroids. Preclinical studies showed that some selective serotonin reuptake inhibitors (SSRIs; fluvoxamine, fluoxetine, excitalopram, donepezil, and ifenprodil act as sigma-1 receptor agonists. Furthermore, sigma-1 receptor agonists could improve the N-methyl-D-aspartate (NMDA antagonist phencyclidine (PCP-induced cognitive deficits in mice. A study using positron emission tomography have demonstrated that an oral administration of fluvoxamine or donepezil could bind to sigma-1 receptor in the healthy human brain, suggesting that sigma-1 receptor might be involved in the therapeutic mechanisms of these drugs. Moreover, case reports suggest that sigma-1 receptor agonists, including fluvoxamine, and ifenprodil, may be effective in the treatment of cognitive impairment in schizophrenia, delirium in elderly people, and flashbacks in post-traumatic stress disorder. In this review article, the author would like to discuss the clinical implication of sigma-1 receptor agonists, including endogenous neurosteroids, in the neuropsychiatric diseases.

  15. Involvement of a novel copper chaperone in tyrosinase activity and melanin synthesis in Marinomonas mediterranea.

    Science.gov (United States)

    López-Serrano, D; Solano, F; Sanchez-Amat, A

    2007-07-01

    Tyrosinase activity and melanin synthesis in the marine bacterium Marinomonas mediterranea in media with very low copper concentrations are dependent on the presence of a protein (PpoB2) that functions as a chaperone to deliver copper to tyrosinase (PpoB1). Under these conditions, mutants in ppoB2 (such as strain T105) produce PpoB1 as an apoenzyme that can be reconstituted to the active holoenzyme by the addition of cupric ions to cell extracts. To study PpoB2 functionality, a system was developed for genetic complementation in M. mediterranea. Using this approach, melanin synthesis was restored in strain T105 when a wild-type copy of ppoB2 was introduced. PpoB2 is a novel protein since it is believed to be the first to be described that contains several motifs similar to metal binding motifs present separately in other types of copper-related protein. At least three motifs, a His-rich N-terminal region, and the short CxxxC and MxxxMM sequences, are essential for the functionality of PpoB2, since site-directed mutagenesis of these motifs resulted in a non-functional protein. In addition, it was demonstrated that PpoB2 is a membrane copper transporter putatively participating in the delivery of this ion specifically to the tyrosinase of M. mediterranea and not to a second copper oxidase showing laccase activity that this micro-organism also expresses. PpoB2 has similarities with the COG5486 group encoding putative transmembrane metal binding proteins, and is believed to be the first protein in this group to be experimentally characterized. It may constitute the first example of a novel type of protein involved in copper trafficking in bacteria.

  16. Promiscuous histone mis-assembly is actively prevented by chaperones | Center for Cancer Research

    Science.gov (United States)

    About the Cover Chaperone HJURP drives the proper loading of protein CENP-A to the centromere of a chromosome. The effect of HJURP on CENP-A's structural dynamics are observed and explained using dual-resolution in silico simulations, while in vivo experiments demonstrate how CENP-A mutations influence its specific localization in human cells. Abstract

  17. Hsp31, a member of the DJ-1 superfamily, is a multitasking stress responder with chaperone activity.

    Science.gov (United States)

    Aslam, Kiran; Hazbun, Tony R

    2016-03-03

    Among different types of protein aggregation, amyloids are a biochemically well characterized state of protein aggregation that are associated with a large number of neurodegenerative diseases including Parkinson's disease, Alzheimer and Creutzfeldt-Jakob disease. Yeast, Saccharomyces cerevisiae is an insightful model to understand the underlying mechanism of protein aggregation. Many yeast molecular chaperones can modulate aggregation and misfolding of proteins including α-Syn and the Sup35 prion. Hsp31 is a homodimeric protein structurally similar to human DJ-1, a Parkinson's disease-linked protein, and both are members of the DJ-1/ThiJ/PfpI superfamily. An emerging view is that Hsp31 and its associated superfamily members each have divergent multitasking functions that have the common theme of responding and managing various types of cellular stress. Hsp31 has several biochemical activities including chaperone and detoxifying enzyme activities that modulate at various points of a stress pathway such as toxicity associated with protein misfolding. However, we have shown the protective role of Hsp31's chaperone activity can operate independent of detoxifying enzyme activities in preventing the early stages of protein aggregate formation and associated cellular toxicities. We provide additional data that collectively supports the multiple functional roles that can be accomplished independent of each other. We present data indicating Hsp31 purified from yeast is more active compared to expression and purification from E. coli suggesting that posttranslational modifications could be important for Hsp31 to be fully active. We also compare the similarities and differences in activities among paralogs of Hsp31 supporting a model in which this protein family has overlapping but diverging roles in responding to various sources of cellular stresses.

  18. Chaperone-like activity of β-casein and its effect on residual in vitro activity of horseradish peroxidase

    DEFF Research Database (Denmark)

    Sulewska, Anna Maria; Olsen, Karsten; Sørensen, Jens Christian

    2014-01-01

    , as similar experiment with bovine serum albumin resulted in residual activity of horseradish peroxidase that was significantly lower than without any addition. The effect of β-casein on HRP disappears when pH is below the isoelectric point of β-casein. It was also proven by light scattering studies that β......In this study, the residual activity horseradish peroxidase was used as a novel marker of chaperone-like activity of β-casein under elevated temperature. It was shown that β-casein does affect residual activity of horseradish peroxidase (HRP) depending on the concentration and molar ratio between...... proteins. Incubating HRP (0.1 mg mL-1) for 10 min at 72 °C resulted in residual activity of 59 ± 5%, while addition of 1 mg mL-1 β-casein resulted in increase in residual activity up to 85 ± 1%. Increased residual activity is not merely attributed to an effect of higher total protein concentration...

  19. Chaperonin 20 might be an iron chaperone for superoxide dismutase in activating iron superoxide dismutase (FeSOD).

    Science.gov (United States)

    Kuo, Wen-Yu; Huang, Chien-Hsun; Jinn, Tsung-Luo

    2013-02-01

    Activation of Cu/Zn superoxide dismutases (CuZnSODs) is aided by Cu incorporation and disulfide isomerization by Cu chaperone of SOD (CCS). As well, an Fe-S cluster scaffold protein, ISU, might alter the incorporation of Fe or Mn into yeast MnSOD (ySOD2), thus leading to active or inactive ySOD2. However, metallochaperones involved in the activation of FeSODs are unknown. Recently, we found that a chloroplastic chaperonin cofactor, CPN20, could mediate FeSOD activity. To investigate whether Fe incorporation in FeSOD is affected by CPN20, we used inductively coupled plasma mass spectrometry to analyze the ability of CPN20 to bind Fe. CPN20 could bind Fe, and the Fe binding to FeSOD was increased with CPN20 incubation. Thus, CPN20 might be an Fe chaperone for FeSOD activation, a role independent of its well-known co-chaperonin activity.

  20. Fidelity of plus-strand priming requires the nucleic acid chaperone activity of HIV-1 nucleocapsid protein

    Science.gov (United States)

    Post, Klara; Kankia, Besik; Gopalakrishnan, Swathi; Yang, Victoria; Cramer, Elizabeth; Saladores, Pilar; Gorelick, Robert J.; Guo, Jianhui; Musier-Forsyth, Karin; Levin, Judith G.

    2009-01-01

    During minus-strand DNA synthesis, RNase H degrades viral RNA sequences, generating potential plus-strand DNA primers. However, selection of the 3′ polypurine tract (PPT) as the exclusive primer is required for formation of viral DNA with the correct 5′-end and for subsequent integration. Here we show a new function for the nucleic acid chaperone activity of HIV-1 nucleocapsid protein (NC) in reverse transcription: blocking mispriming by non-PPT RNAs. Three representative 20-nt RNAs from the PPT region were tested for primer extension. Each primer had activity in the absence of NC, but less than the PPT. NC reduced priming by these RNAs to essentially base-line level, whereas PPT priming was unaffected. RNase H cleavage and zinc coordination by NC were required for maximal inhibition of mispriming. Biophysical properties, including thermal stability, helical structure and reverse transcriptase (RT) binding affinity, showed significant differences between PPT and non-PPT duplexes and the trends were generally correlated with the biochemical data. Binding studies in reactions with both NC and RT ruled out a competition binding model to explain NC's observed effects on mispriming efficiency. Taken together, these results demonstrate that NC chaperone activity has a major role in ensuring the fidelity of plus-strand priming. PMID:19158189

  1. Hyperuricemic PRP in Tendon Cells

    Directory of Open Access Journals (Sweden)

    I. Andia

    2014-01-01

    Full Text Available Platelet-rich plasma (PRP is injected within tendons to stimulate healing. Metabolic alterations such as the metabolic syndrome, diabetes, or hyperuricemia could hinder the therapeutic effect of PRP. We hypothesise that tendon cells sense high levels of uric acid and this could modify their response to PRP. Tendon cells were treated with allogeneic PRPs for 96 hours. Hyperuricemic PRP did not hinder the proliferative actions of PRP. The gene expression pattern of inflammatory molecules in response to PRP showed absence of IL-1b and COX1 and modest expression of IL6, IL8, COX2, and TGF-b1. IL8 and IL6 proteins were secreted by tendon cells treated with PRP. The synthesis of IL6 and IL8 proteins induced by PRP is decreased significantly in the presence of hyperuricemia (P = 0.017 and P = 0.012, resp.. Concerning extracellular matrix, PRP-treated tendon cells displayed high type-1 collagen, moderate type-3 collagen, decorin, and hyaluronan synthase-2 expression and modest expression of scleraxis. Hyperuricemia modified the expression pattern of extracellular matrix proteins, upregulating COL1 (P = 0.036 and COMP (P = 0.012 and downregulating HAS2 (P = 0.012. Positive correlations between TGF-b1 and type-1 collagen (R = 0.905, P = 0.002 and aggrecan (R = 0.833, P = 0.010 and negative correlations between TGF-b1 and IL6 synthesis (R = −0.857, P = 0.007 and COX2 (R = −0.810, P = 0.015 were found.

  2. Structural basis of PP2A activation by PTPA, an ATP-dependent activation chaperone

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Feng; Stanevich, Vitali; Wlodarchak, Nathan; Sengupta, Rituparna; Jiang, Li; Satyshur, Kenneth A.; Xing, Yongna

    2013-10-08

    Proper activation of protein phosphatase 2A (PP2A) catalytic subunit is central for the complex PP2A regulation and is crucial for broad aspects of cellular function. The crystal structure of PP2A bound to PP2A phosphatase activator (PTPA) and ATPγS reveals that PTPA makes broad contacts with the structural elements surrounding the PP2A active site and the adenine moiety of ATP. PTPA-binding stabilizes the protein fold of apo-PP2A required for activation, and orients ATP phosphoryl groups to bind directly to the PP2A active site. This allows ATP to modulate the metal-binding preferences of the PP2A active site and utilize the PP2A active site for ATP hydrolysis. In vitro, ATP selectively and drastically enhances binding of endogenous catalytic metal ions, which requires ATP hydrolysis and is crucial for acquisition of pSer/Thr-specific phosphatase activity. Furthermore, both PP2A- and ATP-binding are required for PTPA function in cell proliferation and survival. Our results suggest novel mechanisms of PTPA in PP2A activation with structural economy and a unique ATP-binding pocket that could potentially serve as a specific therapeutic target.

  3. A copper chaperone for superoxide dismutase that confers three types of copper/zinc superoxide dismutase activity in Arabidopsis.

    Science.gov (United States)

    Chu, Chiung-Chih; Lee, Wen-Chi; Guo, Wen-Yu; Pan, Shu-Mei; Chen, Lih-Jen; Li, Hsou-Min; Jinn, Tsung-Luo

    2005-09-01

    The copper chaperone for superoxide dismutase (CCS) has been identified as a key factor integrating copper into copper/zinc superoxide dismutase (CuZnSOD) in yeast (Saccharomyces cerevisiae) and mammals. In Arabidopsis (Arabidopsis thaliana), only one putative CCS gene (AtCCS, At1g12520) has been identified. The predicted AtCCS polypeptide contains three distinct domains: a central domain, flanked by an ATX1-like domain, and a C-terminal domain. The ATX1-like and C-terminal domains contain putative copper-binding motifs. We have investigated the function of this putative AtCCS gene and shown that a cDNA encoding the open reading frame predicted by The Arabidopsis Information Resource complemented only the cytosolic and peroxisomal CuZnSOD activities in the Atccs knockout mutant, which has lost all CuZnSOD activities. However, a longer AtCCS cDNA, as predicted by the Munich Information Centre for Protein Sequences and encoding an extra 66 amino acids at the N terminus, could restore all three, including the chloroplastic CuZnSOD activities in the Atccs mutant. The extra 66 amino acids were shown to direct the import of AtCCS into chloroplasts. Our results indicated that one AtCCS gene was responsible for the activation of all three types of CuZnSOD activity. In addition, a truncated AtCCS, containing only the central and C-terminal domains without the ATX1-like domain failed to restore any CuZnSOD activity in the Atccs mutant. This result indicates that the ATX1-like domain is essential for the copper chaperone function of AtCCS in planta.

  4. A Copper Chaperone for Superoxide Dismutase That Confers Three Types of Copper/Zinc Superoxide Dismutase Activity in Arabidopsis1

    Science.gov (United States)

    Chu, Chiung-Chih; Lee, Wen-Chi; Guo, Wen-Yu; Pan, Shu-Mei; Chen, Lih-Jen; Li, Hsou-min; Jinn, Tsung-Luo

    2005-01-01

    The copper chaperone for superoxide dismutase (CCS) has been identified as a key factor integrating copper into copper/zinc superoxide dismutase (CuZnSOD) in yeast (Saccharomyces cerevisiae) and mammals. In Arabidopsis (Arabidopsis thaliana), only one putative CCS gene (AtCCS, At1g12520) has been identified. The predicted AtCCS polypeptide contains three distinct domains: a central domain, flanked by an ATX1-like domain, and a C-terminal domain. The ATX1-like and C-terminal domains contain putative copper-binding motifs. We have investigated the function of this putative AtCCS gene and shown that a cDNA encoding the open reading frame predicted by The Arabidopsis Information Resource complemented only the cytosolic and peroxisomal CuZnSOD activities in the Atccs knockout mutant, which has lost all CuZnSOD activities. However, a longer AtCCS cDNA, as predicted by the Munich Information Centre for Protein Sequences and encoding an extra 66 amino acids at the N terminus, could restore all three, including the chloroplastic CuZnSOD activities in the Atccs mutant. The extra 66 amino acids were shown to direct the import of AtCCS into chloroplasts. Our results indicated that one AtCCS gene was responsible for the activation of all three types of CuZnSOD activity. In addition, a truncated AtCCS, containing only the central and C-terminal domains without the ATX1-like domain failed to restore any CuZnSOD activity in the Atccs mutant. This result indicates that the ATX1-like domain is essential for the copper chaperone function of AtCCS in planta. PMID:16126858

  5. Can PRP effectively treat injured tendons?

    Science.gov (United States)

    Wang, James H-C

    2014-01-01

    PRP is widely used to treat tendon and other tissue injuries in orthopaedics and sports medicine; however, the efficacy of PRP treatment on injured tendons is highly controversial. In this commentary, I reason that there are many PRP- and patient-related factors that influence the outcomes of PRP treatment on injured tendons. Therefore, more basic science studies are needed to understand the mechanism of PRP on injured tendons. Finally, I suggest that better understanding of the PRP action mechanism will lead to better use of PRP for the effective treatment of tendon injuries in clinics.

  6. Exploring geometric properties of gold nanoparticles using TEM images to explain their chaperone like activity for citrate synthase.

    Science.gov (United States)

    Kaushik, Vikas; Lahiri, Tapobrata; Singha, Shantiswaroop; Dasgupta, Anjan Kumar; Mishra, Hrishikesh; Kumar, Upendra; Kumar, Rajeev

    2011-01-01

    Study on geometric properties of nanoparticles and their relation with biomolecular activities, especially protein is quite a new field to explore. This work was carried out towards this direction where images of gold nanoparticles obtained from transmission electron microscopy were processed to extract their size and area profile at different experimental conditions including and excluding a protein, citrate synthase. Since the images were ill-posed, texture of a context-window for each pixel was used as input to a back-propagation network architecture to obtain decision on its membership as nanoparticle. The segmented images were further analysed by k-means clustering to derive geometric properties of individual nanoparticles even from their assembled form. The extracted geometric information was found to be crucial to give a model featuring porous cage like configuration of nanoparticle assembly using which the chaperone like activity of gold nanoparticles can be explained.

  7. C-terminal domain modulates the nucleic acid chaperone activity of human T-cell leukemia virus type 1 nucleocapsid protein via an electrostatic mechanism.

    Science.gov (United States)

    Qualley, Dominic F; Stewart-Maynard, Kristen M; Wang, Fei; Mitra, Mithun; Gorelick, Robert J; Rouzina, Ioulia; Williams, Mark C; Musier-Forsyth, Karin

    2010-01-01

    Retroviral nucleocapsid (NC) proteins are molecular chaperones that facilitate nucleic acid (NA) remodeling events critical in viral replication processes such as reverse transcription. Surprisingly, the NC protein from human T-cell leukemia virus type 1 (HTLV-1) is an extremely poor NA chaperone. Using bulk and single molecule methods, we find that removal of the anionic C-terminal domain (CTD) of HTLV-1 NC results in a protein with chaperone properties comparable with that of other retroviral NCs. Increasing the ionic strength of the solution also improves the chaperone activity of full-length HTLV-1 NC. To determine how the CTD negatively modulates the chaperone activity of HTLV-1 NC, we quantified the thermodynamics and kinetics of wild-type and mutant HTLV-1 NC/NA interactions. The wild-type protein exhibits very slow dissociation kinetics, and removal of the CTD or mutations that eliminate acidic residues dramatically increase the protein/DNA interaction kinetics. Taken together, these results suggest that the anionic CTD interacts with the cationic N-terminal domain intramolecularly when HTLV-1 NC is not bound to nucleic acids, and similar interactions occur between neighboring molecules when NC is NA-bound. The intramolecular N-terminal domain-CTD attraction slows down the association of the HTLV-1 NC with NA, whereas the intermolecular interaction leads to multimerization of HTLV-1 NC on the NA. The latter inhibits both NA/NC aggregation and rapid protein dissociation from single-stranded DNA. These features make HTLV-1 NC a poor NA chaperone, despite its robust duplex destabilizing capability.

  8. A single amino acid substitution in ORF1 dramatically decreases L1 retrotransposition and provides insight into nucleic acid chaperone activity.

    Science.gov (United States)

    Martin, Sandra L; Bushman, Diane; Wang, Fei; Li, Patrick Wai-Lun; Walker, Ann; Cummiskey, Jessica; Branciforte, Dan; Williams, Mark C

    2008-10-01

    L1 is a ubiquitous interspersed repeated sequence in mammals that achieved its high copy number by autonomous retrotransposition. Individual L1 elements within a genome differ in sequence and retrotransposition activity. Retrotransposition requires two L1-encoded proteins, ORF1p and ORF2p. Chimeric elements were used to map a 15-fold difference in retrotransposition efficiency between two L1 variants from the mouse genome, T(FC) and T(Fspa), to a single amino acid substitution in ORF1p, D159H. The steady-state levels of L1 RNA and protein do not differ significantly between these two elements, yet new insertions are detected earlier and at higher frequency in T(FC), indicating that it converts expressed L1 intermediates more effectively into new insertions. The two ORF1 proteins were purified and their nucleic acid binding and chaperone activities were examined in vitro. Although the RNA and DNA oligonucleotide binding affinities of these two ORF1 proteins were largely indistinguishable, D159 was significantly more effective as a nucleic acid chaperone than H159. These findings support a requirement for ORF1p nucleic acid chaperone activity at a late step during L1 retrotransposition, extend the region of ORF1p that is known to be critical for its functional interactions with nucleic acids, and enhance understanding of nucleic acid chaperone activity.

  9. Tsp36, a tapeworm small heat-shock protein with a duplicated alpha-crystallin domain, forms dimers and tetramers with good chaperone-like activity.

    NARCIS (Netherlands)

    Kappe, G.; Aquilina, J.A.; Wunderink, L.; Kamps, B.; Robinson, C.V.; Garate, T.; Boelens, W.C.; Jong, W.W.W. de

    2004-01-01

    Small heat shock proteins (sHSPs), which range in monomer size between 12 and 42 kDa, are characterized by a conserved C-terminal alpha-crystallin domain of 80-100 residues. They generally form large homo- or heteromeric complexes, and typically have in vitro chaperone-like activity, keeping

  10. A novel C-terminal homologue of Aha1 co-chaperone binds to heat shock protein 90 and stimulates its ATPase activity in Entamoeba histolytica.

    Science.gov (United States)

    Singh, Meetali; Shah, Varun; Tatu, Utpal

    2014-04-17

    Cytosolic heat shock protein 90 (Hsp90) has been shown to be essential for many infectious pathogens and is considered a potential target for drug development. In this study, we have carried out biochemical characterization of Hsp90 from a poorly studied protozoan parasite of clinical importance, Entamoeba histolytica. We have shown that Entamoeba Hsp90 can bind to both ATP and its pharmacological inhibitor, 17-AAG (17-allylamino-17-demethoxygeldanamycin), with Kd values of 365.2 and 10.77 μM, respectively, and it has a weak ATPase activity with a catalytic efficiency of 4.12×10(-4) min(-1) μM(-1). Using inhibitor 17-AAG, we have shown dependence of Entamoeba on Hsp90 for its growth and survival. Hsp90 function is regulated by various co-chaperones. Previous studies suggest a lack of several important co-chaperones in E. histolytica. In this study, we describe the presence of a novel homologue of co-chaperone Aha1 (activator of Hsp90 ATPase), EhAha1c, lacking a canonical Aha1 N-terminal domain. We also show that EhAha1c is capable of binding and stimulating ATPase activity of EhHsp90. In addition to highlighting the potential of Hsp90 inhibitors as drugs against amoebiasis, our study highlights the importance of E. histolytica in understanding the evolution of Hsp90 and its co-chaperone repertoire. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Plasmodium falciparum Hsp70-z, an Hsp110 homologue, exhibits independent chaperone activity and interacts with Hsp70-1 in a nucleotide-dependent fashion.

    Science.gov (United States)

    Zininga, Tawanda; Achilonu, Ikechukwu; Hoppe, Heinrich; Prinsloo, Earl; Dirr, Heini W; Shonhai, Addmore

    2016-05-01

    The role of molecular chaperones, among them heat shock proteins (Hsps), in the development of malaria parasites has been well documented. Hsp70s are molecular chaperones that facilitate protein folding. Hsp70 proteins are composed of an N-terminal nucleotide binding domain (NBD), which confers them with ATPase activity and a C-terminal substrate binding domain (SBD). In the ADP-bound state, Hsp70 possesses high affinity for substrate and releases the folded substrate when it is bound to ATP. The two domains are connected by a conserved linker segment. Hsp110 proteins possess an extended lid segment, a feature that distinguishes them from canonical Hsp70s. Plasmodium falciparum Hsp70-z (PfHsp70-z) is a member of the Hsp110 family of Hsp70-like proteins. PfHsp70-z is essential for survival of malaria parasites and is thought to play an important role as a molecular chaperone and nucleotide exchange factor of its cytosolic canonical Hsp70 counterpart, PfHsp70-1. Unlike PfHsp70-1 whose functions are fairly well established, the structure-function features of PfHsp70-z remain to be fully elucidated. In the current study, we established that PfHsp70-z possesses independent chaperone activity. In fact, PfHsp70-z appears to be marginally more effective in suppressing protein aggregation than its cytosol-localized partner, PfHsp70-1. Furthermore, based on coimmunoaffinity chromatography and surface plasmon resonance analyses, PfHsp70-z associated with PfHsp70-1 in a nucleotide-dependent fashion. Our findings suggest that besides serving as a molecular chaperone, PfHsp70-z could facilitate the nucleotide exchange function of PfHsp70-1. These dual functions explain why it is essential for parasite survival.

  12. Ric-8A, a G protein chaperone with nucleotide exchange activity induces long-range secondary structure changes in Gα.

    Science.gov (United States)

    Kant, Ravi; Zeng, Baisen; Thomas, Celestine J; Bothner, Brian; Sprang, Stephen R

    2016-12-23

    Cytosolic Ric-8A has guanine nucleotide exchange factor (GEF) activity and is a chaperone for several classes of heterotrimeric G protein α subunits in vertebrates. Using Hydrogen-Deuterium Exchange-Mass Spectrometry (HDX-MS) we show that Ric-8A disrupts the secondary structure of the Gα Ras-like domain that girds the guanine nucleotide-binding site, and destabilizes the interface between the Gαi1 Ras and helical domains, allowing domain separation and nucleotide release. These changes are largely reversed upon binding GTP and dissociation of Ric-8A. HDX-MS identifies a potential Gα interaction site in Ric-8A. Alanine scanning reveals residues crucial for GEF activity within that sequence. HDX confirms that, like G protein-coupled receptors (GPCRs), Ric-8A binds the C-terminus of Gα. In contrast to GPCRs, Ric-8A interacts with Switches I and II of Gα and possibly at the Gα domain interface. These extensive interactions provide both allosteric and direct catalysis of GDP unbinding and release and GTP binding.

  13. Inhibition of chaperone-mediated autophagy prevents glucotoxicity in the Caenorhabditis elegans mev-1 mutant by activation of the proteasome.

    Science.gov (United States)

    Eisermann, Dorothé Jenni; Wenzel, Uwe; Fitzenberger, Elena

    2017-02-26

    Chronic hyperglycemia is a hallmark of diabetes mellitus and the main cause of diabetes-associated complications. Increased intracellular glucose levels lead to damaged proteins and in consequence disturb cellular proteostasis. As an important contributor to the maintenance and restoration of proteostasis, autophagy mediates the lysosomal degradation of damaged proteins or entire cellular organelles. In the present study we used the stress-sensitive mev-1 mutant of the nematode Caenorhabditis elegans in order to assess the role of lmp-2, a homologue of the lysosome associated membrane protein type 2A, in the context of glucotoxicity, which was achieved by feeding glucose in a liquid medium. Knockdown of lmp-2 by RNA interference completely prevented the survival reduction caused by glucose under heat stress. Those effects were associated with the prevention of (1) increased lysosome formation and (2) reduction of proteasomal activity, which were observed under glucose feeding. Finally, the survival reduction due to knockdown of ubiquitin remained unaffected by the additional lmp-2 knockdown in the absence or presence of glucose. In conclusion, our study provides evidence that lmp-2, a key player in chaperone-mediated autophagy, is functional in C. elegans, too. Inhibition of lmp-2 prevents the reduction of proteasomal activity by glucose and thereby prevents also glucotoxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The metal chaperone Atox1 regulates the activity of the human copper transporter ATP7B by modulating domain dynamics.

    Science.gov (United States)

    Yu, Corey H; Yang, Nan; Bothe, Jameson; Tonelli, Marco; Nokhrin, Sergiy; Dolgova, Natalia V; Braiterman, Lelita; Lutsenko, Svetlana; Dmitriev, Oleg Y

    2017-11-03

    The human transporter ATP7B delivers copper to the biosynthetic pathways and maintains copper homeostasis in the liver. Mutations in ATP7B cause the potentially fatal hepatoneurological disorder Wilson disease. The activity and intracellular localization of ATP7B are regulated by copper, but the molecular mechanism of this regulation is largely unknown. We show that the copper chaperone Atox1, which delivers copper to ATP7B, and the group of the first three metal-binding domains (MBD1-3) are central to the activity regulation of ATP7B. Atox1-Cu binding to ATP7B changes domain dynamics and interactions within the MBD1-3 group and activates ATP hydrolysis. To understand the mechanism linking Atox1-MBD interactions and enzyme activity, we have determined the MBD1-3 conformational space using small angle X-ray scattering and identified changes in MBD dynamics caused by apo-Atox1 and Atox1-Cu by solution NMR. The results show that copper transfer from Atox1 decreases domain interactions within the MBD1-3 group and increases the mobility of the individual domains. The N-terminal segment of MBD1-3 was found to interact with the nucleotide-binding domain of ATP7B, thus physically coupling the domains involved in copper binding and those involved in ATP hydrolysis. Taken together, the data suggest a regulatory mechanism in which Atox1-mediated copper transfer activates ATP7B by releasing inhibitory constraints through increased freedom of MBD1-3 motions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Molecular chaperone assisted expression systems: obtaining pure soluble and active recombinant proteins for structural and therapeutic purposes

    CSIR Research Space (South Africa)

    Makhoba, XH

    2015-09-01

    Full Text Available during recombinant proteins production in E. coli. Molecular chaperones are proteins that are known to assist the newly synthesized proteins to complete their folding stages. This system has improved various proteins that are difficult to produce in E...

  16. Approaches to the isolation and characterization of molecular chaperones.

    Science.gov (United States)

    Nicoll, William S; Boshoff, Aileen; Ludewig, Michael H; Hennessy, Fritha; Jung, Martin; Blatch, Gregory L

    2006-03-01

    Molecular chaperones are integral components of the cellular machinery involved in ensuring correct protein folding and the continued maintenance of protein structure. An understanding of these ubiquitous molecules is key to finding cures to protein misfolding diseases such as Alzheimer's and Creutzfeldt-Jacob diseases. In addition, further understanding of chaperones will enhance our comprehension of the way the body copes with the environmental stresses that humans encounter daily. Our laboratory and our collaborators specialize in the production and characterization of chaperones from a wide variety of sources in order to gain a fuller understanding of how chaperones function in the cell. In this review, we primarily use the Hsp70/Hsp40 chaperone pair as an example to discuss recent advances in technology and reductions in cost that lend themselves to chaperone purification from both native and recombinant sources. Common assays to assess purified chaperone activity are also discussed.

  17. Evaluation of molecular chaperons Hsp72 and neuropeptide Y as characteristic markers of adaptogenic activity of plant extracts.

    Science.gov (United States)

    Asea, Alexzander; Kaur, Punit; Panossian, Alexander; Wikman, Karl Georg

    2013-11-15

    We have previously demonstrated that ADAPT-232, a fixed combination of adaptogenic substances derived from Eleutherococcus senticosus root extract, Schisandra chinensis berry extract, Rhodiola rosea root extract stimulated the expression and release of neuropeptide Y (NPY) and molecular chaperone Hsp72 from isolated human neurolgia cells. Both of these mediators of stress response are known to play an important role in regulation of neuroendocrine system and immune response. We further demonstrated that ADAPT-232 induced release of Hsp70 is mediated by NPY, suggesting an existence of NPY-mediated pathway of activation of Hsp72 release into the blood circulation system. The objective of this study was to determine whether this pathway is common for adaptogens and whether NPY and/or Hsp72 can be considered as necessary specific biomarkers for adaptogenic activity. The release of NPY and Hsp72 from neuroglia cells in response to treatment with various plant extracts (n=23) including selected validated adaptogens, partly validated adaptogens, claimed but negligibly validated adaptogens and some other plant extracts affecting neuroendocrine and immune systems but never considered as adaptogens was measured using high throughput ELISA techniques. We demonstrated that adaptogens, e.g. R. rosea, S. chinensis and E. senticosus stimulate both NPY and Hsp70 release from neuroblastoma cells, while tonics and stimulants have no significant effect on NPY in this in vitro test. In the groups of partly validated adaptogens the effect of Panax ginseng and Withania somnifera was not statistically significant both on NPY and Hsp70 release, while the activating effect of Bryonia alba and Rhaponticum cartamoides was significant only on Hsp70. In contrast, all tested non-adaptogens, such as antiinflammatoty plant extracts Matricaria recutita, Pelargonium sidoides, Hedera helix and Vitis vinifera significantly inhibit Hsp70 release and have no influence on NPY release from neuroblastoma

  18. The Salmonella type III effector SspH2 specifically exploits the NLR co-chaperone activity of SGT1 to subvert immunity.

    Directory of Open Access Journals (Sweden)

    Amit P Bhavsar

    Full Text Available To further its pathogenesis, S. Typhimurium delivers effector proteins into host cells, including the novel E3 ubiquitin ligase (NEL effector SspH2. Using model systems in a cross-kingdom approach we gained further insight into the molecular function of this effector. Here, we show that SspH2 modulates innate immunity in both mammalian and plant cells. In mammalian cell culture, SspH2 significantly enhanced Nod1-mediated IL-8 secretion when transiently expressed or bacterially delivered. In addition, SspH2 also enhanced an Rx-dependent hypersensitive response in planta. In both of these nucleotide-binding leucine rich repeat receptor (NLR model systems, SspH2-mediated phenotypes required its catalytic E3 ubiquitin ligase activity and interaction with the conserved host protein SGT1. SGT1 has an essential cell cycle function and an additional function as an NLR co-chaperone in animal and plant cells. Interaction between SspH2 and SGT1 was restricted to SGT1 proteins that have NLR co-chaperone function and accordingly, SspH2 did not affect SGT1 cell cycle functions. Mechanistic studies revealed that SspH2 interacted with, and ubiquitinated Nod1 and could induce Nod1 activity in an agonist-independent manner if catalytically active. Interestingly, SspH2 in vitro ubiquitination activity and protein stability were enhanced by SGT1. Overall, this work adds to our understanding of the sophisticated mechanisms used by bacterial effectors to co-opt host pathways by demonstrating that SspH2 can subvert immune responses by selectively exploiting the functions of a conserved host co-chaperone.

  19. Structural and functional analysis of the human spliceosomal DEAD-box helicase Prp28

    Energy Technology Data Exchange (ETDEWEB)

    Möhlmann, Sina [Georg-August-University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen (Germany); Mathew, Rebecca [Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, 37077 Göttingen (Germany); Neumann, Piotr; Schmitt, Andreas [Georg-August-University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen (Germany); Lührmann, Reinhard [Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, 37077 Göttingen (Germany); Ficner, Ralf, E-mail: rficner@uni-goettingen.de [Georg-August-University Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen (Germany)

    2014-06-01

    The crystal structure of the helicase domain of the human spliceosomal DEAD-box protein Prp28 was solved by SAD. The binding of ADP and ATP by Prp28 was studied biochemically and analysed with regard to the crystal structure. The DEAD-box protein Prp28 is essential for pre-mRNA splicing as it plays a key role in the formation of an active spliceosome. Prp28 participates in the release of the U1 snRNP from the 5′-splice site during association of the U5·U4/U6 tri-snRNP, which is a crucial step in the transition from a pre-catalytic spliceosome to an activated spliceosome. Here, it is demonstrated that the purified helicase domain of human Prp28 (hPrp28ΔN) binds ADP, whereas binding of ATP and ATPase activity could not be detected. ATP binding could not be observed for purified full-length hPrp28 either, but within an assembled spliceosomal complex hPrp28 gains ATP-binding activity. In order to understand the structural basis for the ATP-binding deficiency of isolated hPrp28, the crystal structure of hPrp28ΔN was determined at 2.0 Å resolution. In the crystal the helicase domain adopts a wide-open conformation, as the two RecA-like domains are extraordinarily displaced from the productive ATPase conformation. Binding of ATP is hindered by a closed conformation of the P-loop, which occupies the space required for the γ-phosphate of ATP.

  20. A Chaperone Function of NO CATALASE ACTIVITY1 Is Required to Maintain Catalase Activity and for Multiple Stress Responses in Arabidopsis

    Science.gov (United States)

    Li, Jing; Liu, Juntao; Wang, Guoqiang; Cha, Joon-Yung; Li, Guannan; Chen, She; Li, Zhen; Guo, Jinghua; Zhang, Caiguo; Yang, Yongqing; Kim, Woe-Yeon; Yun, Dae-Jin; Schumaker, Karen S.; Chen, Zhongzhou; Guo, Yan

    2015-01-01

    Catalases are key regulators of reactive oxygen species homeostasis in plant cells. However, the regulation of catalase activity is not well understood. In this study, we isolated an Arabidopsis thaliana mutant, no catalase activity1-3 (nca1-3) that is hypersensitive to many abiotic stress treatments. The mutated gene was identified by map-based cloning as NCA1, which encodes a protein containing an N-terminal RING-finger domain and a C-terminal tetratricopeptide repeat-like helical domain. NCA1 interacts with and increases catalase activity maximally in a 240-kD complex in planta. In vitro, NCA1 interacts with CATALASE2 (CAT2) in a 1:1 molar ratio, and the NCA1 C terminus is essential for this interaction. CAT2 activity increased 10-fold in the presence of NCA1, and zinc ion binding of the NCA1 N terminus is required for this increase. NCA1 has chaperone protein activity that may maintain the folding of catalase in a functional state. NCA1 is a cytosol-located protein. Expression of NCA1 in the mitochondrion of the nca1-3 mutant does not rescue the abiotic stress phenotypes of the mutant, while expression in the cytosol or peroxisome does. Our results suggest that NCA1 is essential for catalase activity. PMID:25700484

  1. In vitro study of the role of thrombin in platelet rich plasma (PRP) preparation: utility for gel formation and impact in growth factors release

    Science.gov (United States)

    Huber, Stephany Cares; Cunha Júnior, José Luiz Rosenberis; Montalvão, Silmara; da Silva, Letícia Queiroz; Paffaro, Aline Urban; da Silva, Francesca Aparecida Ramos; Rodrigues, Bruno Lima; Lana, José Fabio Santos Duarte; Annichino-Bizzacchi, Joyce Maria

    2016-01-01

    Introduction: The use of PRP has been studied for different fields, with promising results in regenerative medicine. Until now, there is no study in the literature evaluating thrombin levels in serum, used as autologous thrombin preparation. Therefore, in the present study we evaluated the role played by different thrombin concentrations in PRP and the impact in the release of growth factors. Also, different activators for PRP gel formation were evaluated. Methods: Thrombin levels were measured in different autologous preparations: serum, L-PRP (PRP rich in leukocytes) and T-PRP (thrombin produced through PRP added calcium gluconate). L-PRP was prepared according to the literature, with platelets and leukocytes being quantified. The effect of autologous thrombin associated or not with calcium in PRP gel was determined by measuring the time of gel formation. The relationship between thrombin concentration and release of growth factors was determined by growth factors (PDGF-AA, VEGF and EGF) multiplex analysis. Results: A similar concentration of thrombin was observed in serum, L-PRP and T-PRP (8.13 nM, 8.63 nM and 7.56 nM, respectively) with a high variation between individuals (CV%: 35.07, 43 and 58.42, respectively). T-PRP and serum with calcium chloride showed similar results in time to promote gel formation. The increase of thrombin concentrations (2.66, 8 and 24 nM) did not promote an increase in growth factor release. Conclusions: The technique of using serum as a thrombin source proved to be the most efficient and reproducible for promoting PRP gel formation, with some advantages when compared to other activation methods, as this technique is easier and quicker with no need of consuming part of PRP. Noteworthy, PRP activation using different thrombin concentrations did not promote a higher release of growth factors, appearing not to be necessary when PRP is used as a suspension. PMID:27397996

  2. Multitasking SecB chaperones in bacteria

    Directory of Open Access Journals (Sweden)

    Ambre eSala

    2014-12-01

    Full Text Available Protein export in bacteria is facilitated by the canonical SecB chaperone, which binds to unfolded precursor proteins, maintains them in a translocation competent state and specifically cooperates with the translocase motor SecA to ensure their proper targeting to the Sec translocon at the cytoplasmic membrane. Besides its key contribution to the Sec pathway, SecB chaperone tasking is critical for the secretion of the Sec-independent heme-binding protein HasA and actively contributes to the cellular network of chaperones that control general proteostasis in Escherichia coli, as judged by the significant interplay found between SecB and the Trigger Factor, DnaK and GroEL chaperones. Although SecB is mainly a proteobacterial chaperone associated with the presence of an outer membrane and outer membrane proteins, secB-like genes are also found in Gram-positive bacteria as well as in certain phages and plasmids, thus suggesting alternative functions. In addition, a SecB-like protein is also present in the major human pathogen M. tuberculosis where it specifically controls a stress-responsive toxin-antitoxin (TA system. This review focuses on such very diverse chaperone functions of SecB, both in E. coli and in other unrelated bacteria.

  3. Multitasking SecB chaperones in bacteria.

    Science.gov (United States)

    Sala, Ambre; Bordes, Patricia; Genevaux, Pierre

    2014-01-01

    Protein export in bacteria is facilitated by the canonical SecB chaperone, which binds to unfolded precursor proteins, maintains them in a translocation competent state and specifically cooperates with the translocase motor SecA to ensure their proper targeting to the Sec translocon at the cytoplasmic membrane. Besides its key contribution to the Sec pathway, SecB chaperone tasking is critical for the secretion of the Sec-independent heme-binding protein HasA and actively contributes to the cellular network of chaperones that control general proteostasis in Escherichia coli, as judged by the significant interplay found between SecB and the trigger factor, DnaK and GroEL chaperones. Although SecB is mainly a proteobacterial chaperone associated with the presence of an outer membrane and outer membrane proteins, secB-like genes are also found in Gram-positive bacteria as well as in certain phages and plasmids, thus suggesting alternative functions. In addition, a SecB-like protein is also present in the major human pathogen Mycobacterium tuberculosis where it specifically controls a stress-responsive toxin-antitoxin system. This review focuses on such very diverse chaperone functions of SecB, both in E. coli and in other unrelated bacteria.

  4. Myc-oncogene inactivating effect by proline rich polypeptide (PRP-1) in chondrosarcoma JJ012 cells.

    Science.gov (United States)

    Galoian, Karina; Scully, Sean; Galoyan, Armen

    2009-02-01

    Proline rich polypeptide (PRP-1) produced by NPV and NSO cells is released into the general circulation and exerts its effect on the activity of immunocompetent and neuronal cells. PRP-1 is a unique regulator of hematopoiesis, stimulator of bone-marrow hematogenesis. Taking into consideration our preliminary data on antitumor and unique diverse biological properties of PRP-1 previously described by Galoyan et al., we proceeded with investigation of the PRP-1 effect on chondrosarcoma, the second most common malignancy in bone, which tends to be locally invasive and then metastatic. Currently it does not have any effective treatment and does not respond either to radiation or chemotherapy, leaving surgical resection as the only option. Our experimental results of PRP-1 action on human chondrosarcoma JJ012 cells demonstrated inactivation, abolishment of Myc oncogene activity usually upregulated in chondrosarcoma cells and other malignancies. The fact that addition of PRP-1 caused drastic inactivation of Myc-luc response element to the control level in human chondrosarcoma JJ012 cell line prompts to investigate further this neuropeptides powerful antioncogenic potential, opening up possibilities to consider PRP-1 as a potential therapeutic tool for chondrosarcoma treatment.

  5. A Hypothetical Protein of Alteromonas macleodii AltDE1 (amad1_06475) Predicted to be a Cold-Shock Protein with RNA Chaperone Activity.

    Science.gov (United States)

    Oany, Arafat Rahman; Ahmad, Shah Adil Ishtiyaq; Kibria, Km Kaderi; Hossain, Mohammad Uzzal; Jyoti, Tahmina Pervin

    2014-01-01

    Alteromonas macleodii AltDE1 is a deep sea protobacteria that is distinct from the surface isolates of the same species. This study was designed to elucidate the biological function of amad1_06475, a hypothetical protein of A. macleodii AltDE1. The 70 residues protein sequence showed considerable homology with cold-shock proteins (CSPs) and RNA chaperones from different organisms. Multiple sequence alignment further supported the presence of conserved csp domain on the protein sequence. The three-dimensional structure of the protein was also determined, and verified by PROCHECK, Verify3D, and QMEAN programs. The predicted structure contained five anti-parallel β-strands and RNA-binding motifs, which are characteristic features of prokaryotic CSPs. Finally, the binding of a thymidine-rich oligonucleotide and a single uracil molecule in the active site of the protein further strengthens our prediction about the function of amad1_06475 as a CSP and thereby acting as a RNA chaperone. The binding was performed by molecular docking tools and was compared with similar binding of 3PF5 (PDB) and 2HAX (PDB), major CSPs of Bacillus subtilis and Bacillus caldolyticus, respectively.

  6. Molecular crime and cellular punishment: active detoxification of misfolded and aggregated proteins in the cell by the chaperone and protease networks.

    Science.gov (United States)

    Hinault, Marie-Pierre; Goloubinoff, Pierre

    2007-01-01

    Labile or mutation-sensitised proteins may spontaneously convert into aggregation-prone conformations that may be toxic and infectious. This hazardous behavior, which can be described as a form of "molecular criminality", can be actively counteracted in the cell by a network of molecular chaperone and proteases. Similar to law enforcement agents, molecular chaperones and proteases can specifically identify, apprehend, unfold and thus neutralize "criminal" protein conformers, allowing them to subsequently refold into harmless functional proteins. Irreversibly damaged polypeptides that have lost the ability to natively refold are preferentially degraded by highly controlled ATP-consuming proteases. Damaged proteins that escape proteasomal degradation can also be "incarcerated" into dense amyloids, "evicted" from the cell, or internally "exiled" to the lysosome to be hydrolysed and recycled. Thus, remarkable parallels exist between molecular and human forms of criminality, as well as in the cellular and social responses to various forms of crime. Yet, differences also exist: whereas programmed death is the preferred solution chosen by aged and aggregation-stressed cells, collective suicide is seldom chosen by lawless societies. Significantly, there is no cellular equivalent for the role of familial care and of education in general, which is so crucial to the proper shaping of functional persons in the society. Unlike in the cell, humanism introduces a bias against radical solutions such as capital punishment, favouring crime prevention, reeducation and social reinsertion of criminals.

  7. Functional and evolutionary analyses of Helicobacter pylori HP0231 (DsbK protein with strong oxidative and chaperone activity characterized by a highly diverged dimerization domain

    Directory of Open Access Journals (Sweden)

    Katarzyna Marta Bocian-Ostrzycka

    2015-10-01

    Full Text Available Helicobacter pylori does not encode the classical DsbA/DsbB oxidoreductases that are crucial for oxidative folding of extracytoplasmic proteins. Instead, this microorganism encodes an untypical two proteins playing a role in disulfide bond formation – periplasmic HP0231, which structure resembles that of EcDsbC/DsbG, and its redox partner, a membrane protein HpDsbI (HP0595 with a -propeller structure. The aim of presented work was to assess relations between HP0231 structure and function.We showed that HP0231 is most closely related evolutionarily to the catalytic domain of DsbG, even though it possesses a catalytic motif typical for canonical DsbA proteins. Similarly, the highly diverged N-terminal dimerization domain is homologous to the dimerization domain of DsbG. To better understand the functioning of this atypical oxidoreductase, we examined its activity using in vivo and in vitro experiments. We found that HP0231 exhibits oxidizing and chaperone activities but no isomerizing activity, even though H. pylori does not contain a classical DsbC. We also show that HP0231 is not involved in the introduction of disulfide bonds into HcpC (Helicobacter cysteine-rich protein C, a protein involved in the modulation of the H. pylori interaction with its host. Additionally, we also constructed a truncated version of HP0231 lacking the dimerization domain, denoted HP0231m, and showed that it acts in E. coli cells in a DsbB-dependent manner. In contrast, HP0231m and classical monomeric EcDsbA (Escherichia coli DsbA protein were both unable to complement the lack of HP0231 in H. pylori cells, though they exist in oxidized forms. HP0231m is inactive in the insulin reduction assay and possesses high chaperone activity, in contrast to EcDsbA. In conclusion, HP0231 combines oxidative functions characteristic of DsbA proteins and chaperone activity characteristic of DsbC/DsbG, and it lacks isomerization activity.

  8. Patients' attitudes to chaperones

    OpenAIRE

    Jones, Roger

    1985-01-01

    In a survey of 200 female patients attending a five-man practice in a health centre, 75 per cent of the respondents stated that they would like to be offered a chaperone at pelvic examinations. Only six per cent would accept the offer if the examination was performed by their own doctor and 17 per cent if a different doctor examined them. Patients expressing a definite wish for a chaperone were significantly younger and were less likely to have had a previous pelvic examination. Those who def...

  9. The Endoplasmic Reticulum Chaperone GRP78/BiP Modulates Prion Propagation in vitro and in vivo.

    Science.gov (United States)

    Park, Kyung-Won; Eun Kim, Gyoung; Morales, Rodrigo; Moda, Fabio; Moreno-Gonzalez, Ines; Concha-Marambio, Luis; Lee, Amy S; Hetz, Claudio; Soto, Claudio

    2017-03-23

    Prion diseases are fatal neurodegenerative disorders affecting several mammalian species, characterized by the accumulation of the misfolded form of the prion protein, which is followed by the induction of endoplasmic reticulum (ER) stress and the activation of the unfolded protein response (UPR). GRP78, also called BiP, is a master regulator of the UPR, reducing ER stress levels and apoptosis due to an enhancement of the cellular folding capacity. Here, we studied the role of GRP78 in prion diseases using several in vivo and in vitro approaches. Our results show that a reduction in the expression of this molecular chaperone accelerates prion pathogenesis in vivo. In addition, we observed that prion replication in cell culture was inversely related to the levels of expression of GRP78 and that both proteins interact in the cellular context. Finally, incubation of PrP Sc with recombinant GRP78 led to the dose-dependent reduction of protease-resistant PrP Sc in vitro. Our results uncover a novel role of GRP78 in reducing prion pathogenesis, suggesting that modulating its levels/activity may offer a novel opportunity for designing therapeutic approaches for these diseases. These findings may also have implications for other diseases involving the accumulation of misfolded proteins.

  10. C-terminal Domain Modulates the Nucleic Acid Chaperone Activity of Human T-cell Leukemia Virus Type 1 Nucleocapsid Protein via an Electrostatic Mechanism*

    OpenAIRE

    Qualley, Dominic F.; Stewart-Maynard, Kristen M.; Wang, Fei; Mitra, Mithun; Gorelick, Robert J.; Rouzina, Ioulia; Williams, Mark C.; Musier-Forsyth, Karin

    2009-01-01

    Retroviral nucleocapsid (NC) proteins are molecular chaperones that facilitate nucleic acid (NA) remodeling events critical in viral replication processes such as reverse transcription. Surprisingly, the NC protein from human T-cell leukemia virus type 1 (HTLV-1) is an extremely poor NA chaperone. Using bulk and single molecule methods, we find that removal of the anionic C-terminal domain (CTD) of HTLV-1 NC results in a protein with chaperone properties comparable with that of other retrovir...

  11. Binding of 3,4,5,6-Tetrahydroxyazepanes to the Acid-[beta]-glucosidase Active Site: Implications for Pharmacological Chaperone Design for Gaucher Disease

    Energy Technology Data Exchange (ETDEWEB)

    Orwig, Susan D.; Tan, Yun Lei; Grimster, Neil P.; Yu, Zhanqian; Powers, Evan T.; Kelly, Jeffery W.; Lieberman, Raquel L. (Scripps); (GIT)

    2013-03-07

    Pharmacologic chaperoning is a therapeutic strategy being developed to improve the cellular folding and trafficking defects associated with Gaucher disease, a lysosomal storage disorder caused by point mutations in the gene encoding acid-{beta}-glucosidase (GCase). In this approach, small molecules bind to and stabilize mutant folded or nearly folded GCase in the endoplasmic reticulum (ER), increasing the concentration of folded, functional GCase trafficked to the lysosome where the mutant enzyme can hydrolyze the accumulated substrate. To date, the pharmacologic chaperone (PC) candidates that have been investigated largely have been active site-directed inhibitors of GCase, usually containing five- or six-membered rings, such as modified azasugars. Here we show that a seven-membered, nitrogen-containing heterocycle (3,4,5,6-tetrahydroxyazepane) scaffold is also promising for generating PCs for GCase. Crystal structures reveal that the core azepane stabilizes GCase in a variation of its proposed active conformation, whereas binding of an analogue with an N-linked hydroxyethyl tail stabilizes GCase in a conformation in which the active site is covered, also utilizing a loop conformation not seen previously. Although both compounds preferentially stabilize GCase to thermal denaturation at pH 7.4, reflective of the pH in the ER, only the core azepane, which is a mid-micromolar competitive inhibitor, elicits a modest increase in enzyme activity for the neuronopathic G202R and the non-neuronopathic N370S mutant GCase in an intact cell assay. Our results emphasize the importance of the conformational variability of the GCase active site in the design of competitive inhibitors as PCs for Gaucher disease.

  12. PRP and Articular Cartilage: A Clinical Update

    Directory of Open Access Journals (Sweden)

    Antonio Marmotti

    2015-01-01

    Full Text Available The convincing background of the recent studies, investigating the different potentials of platelet-rich plasma, offers the clinician an appealing alternative for the treatment of cartilage lesions and osteoarthritis. Recent evidences in literature have shown that PRP may be helpful both as an adjuvant for surgical treatment of cartilage defects and as a therapeutic tool by intra-articular injection in patients affected by osteoarthritis. In this review, the authors introduce the trophic and anti-inflammatory properties of PRP and the different products of the available platelet concentrates. Then, in a complex scenario made of a great number of clinical variables, they resume the current literature on the PRP applications in cartilage surgery as well as the use of intra-articular PRP injections for the conservative treatment of cartilage degenerative lesions and osteoarthritis in humans, available as both case series and comparative studies. The result of this review confirms the fascinating biological role of PRP, although many aspects yet remain to be clarified and the use of PRP in a clinical setting has to be considered still exploratory.

  13. Portable Radiation Package (PRP) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, R Michael [Remote Measurements and Research Company, Seattle, WA (United States)

    2017-08-03

    The Portable Radiation Package (PRP) was developed to provide basic radiation information in locations such as ships at sea where proper exposure is remote and difficult, the platform is in motion, and azimuth alignment is not fixed. Development of the PRP began at Brookhaven National Laboratory (BNL) in the mid-1990s and versions of it were deployed on ships in the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Nauru-99 project. The PRP was deployed on ships in support of the National Aeronautics and Space Administration (NASA) Sensor Intercomparison for Marine Biological and Interdisciplinary Ocean Studies (SIMBIOS) program. Over the years the measurements have remained the same while the post-processing data analysis, especially for the FRSR, has evolved. This document describes the next-generation Portable Radiation Package (PRP2) that was developed for the DOE ARM Facility, under contract no. 9F-31462 from Argonne National Laboratory (ANL). The PRP2 has the same scientific principles that were well validated in prior studies, but has upgraded electronic hardware. The PRP2 approach is completely modular, both in hardware and software. Each sensor input is treated as a separate serial stream into the data collection computer. In this way the operator has complete access to each component of the system for purposes of error checking, calibration, and maintenance. The resulting system is more reliable, easier to install in complex situations, and more amenable to upgrade.

  14. Crystal Structure of the C-terminal Domain of Splicing Factor Prp8 Carrying Retinitis Pigmentosa Mutants

    Energy Technology Data Exchange (ETDEWEB)

    Zhang,L.; Shen, J.; Guarnieri, M.; Heroux, A.; Yang, K.; Zhao, R.

    2007-01-01

    Prp8 is a critical pre-mRNA splicing factor. Prp8 is proposed to help form and stabilize the spliceosome catalytic core and to be an important regulator of spliceosome activation. Mutations in human Prp8 (hPrp8) cause a severe form of the genetic disorder retinitis pigmentosa, RP13. Understanding the molecular mechanism of Prp8's function in pre-mRNA splicing and RP13 has been hindered by its large size (over 2000 amino acids) and remarkably low-sequence similarity with other proteins. Here we present the crystal structure of the C-terminal domain (the last 273 residues) of Caenorhabditis elegans Prp8 (cPrp8). The core of the C-terminal domain is an / structure that forms the MPN (Mpr1, Pad1 N-terminal) fold but without Zn{sup 2+} coordination. We propose that the C-terminal domain is a protein interaction domain instead of a Zn{sup 2+}-dependent metalloenzyme as proposed for some MPN proteins. Mapping of RP13 mutants on the Prp8 structure suggests that these residues constitute a binding surface between Prp8 and other partner(s), and the disruption of this interaction provides a plausible molecular mechanism for RP13.

  15. N-terminal arm of orchardgrass Hsp17.2 (DgHsp17.2) is essential for both in vitro chaperone activity and in vivo thermotolerance in yeast.

    Science.gov (United States)

    Cha, Joon-Yung; Lee, Sang-Hoon; Seo, Kyung Hye; Choi, Young Jin; Cheong, Mi Sun; Son, Daeyoung

    2016-02-01

    Small heat shock proteins are well-known to function as chaperone in the protection of proteins and subcellular structures against stress-induced denaturation in many cell compartments. Irrespective of such general functional assignment, a proof of function in a living organism is missing. Here, we used heat-induced orchardgrass small Hsp17.2 (DgHsp17.2). Its function in in vitro chaperone properties has shown in protecting the model substrate, malate dehydrogenase (MDH) and citrate synthase (CS). Overexpression of DgHsp17.2 triggering strong chaperone activity enhanced in vivo thermotolerance of yeast cells. To identify the functional domain on DgHsp17.2 and correlationship between in vitro chaperone property and in vivo thermotolerance, we generated truncation mutants of DgHsp17.2 and showed essentiality of the N-terminal arm of DgHsp17.2 for the chaperone function. In addition, beyond for acquisition of thermotolerance irrespective of sequences are diverse among the small Hsps. However, any truncation mutants of DgHsp17.2 did not exhibit strong interaction with orchardgrass heat shock protein 70 (DgHsp70) different from mature DgHsp17.2, indicating that full-length DgHsp17.2 is necessary for cooperating with Hsp70 protein. Our study indicates that the N-terminal arm of DgHsp17.2 is an important region for chaperone activity and thermotolerance. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. The Hsp90 chaperone in action: following the ATP cycle of a molecular machine

    NARCIS (Netherlands)

    Karagoz, G.E.

    2011-01-01

    Protein folding in the cell is assisted by molecular chaperones. Hsp90 is the most abundant molecular chaperone in the cytosol. It facilitates the folding and activation of mainly signalling molecules. Its chaperoning of regulatory proteins places Hsp90 in the cross road of several important

  17. Copper Chaperone-Dependent and -Independent Activation of Three Copper-Zinc Superoxide Dismutase Homologs Localized in Different Cellular Compartments in Arabidopsis1[W][OA

    Science.gov (United States)

    Huang, Chien-Hsun; Kuo, Wen-Yu; Weiss, Celeste; Jinn, Tsung-Luo

    2012-01-01

    Superoxide dismutases (SODs) are important antioxidant enzymes that catalyze the disproportionation of superoxide anion to oxygen and hydrogen peroxide to guard cells against superoxide toxicity. The major pathway for activation of copper/zinc SOD (CSD) involves a copper chaperone for SOD (CCS) and an additional minor CCS-independent pathway reported in mammals. We characterized the CCS-dependent and -independent activation pathways for three CSDs localized in different cellular compartments in Arabidopsis (Arabidopsis thaliana). The main activation pathway for CSD1 in the cytoplasm involved a CCS-dependent and -independent pathway, which was similar to that for human CSD. Activation of CSD2 in chloroplasts depended totally on CCS, similar to yeast (Saccharomyces cerevisiae) CSD. Peroxisome-localized CSD3 via a CCS-independent pathway was similar to nematode (Caenorhabditis elegans) CSD in retaining activity in the absence of CCS. In Arabidopsis, glutathione played a role in CCS-independent activation, as was reported in humans, but an additional factor was required. These findings reveal a highly specific and sophisticated regulation of CSD activation pathways in planta relative to other known CCS-independent activation. PMID:22186608

  18. Copper chaperone-dependent and -independent activation of three copper-zinc superoxide dismutase homologs localized in different cellular compartments in Arabidopsis.

    Science.gov (United States)

    Huang, Chien-Hsun; Kuo, Wen-Yu; Weiss, Celeste; Jinn, Tsung-Luo

    2012-02-01

    Superoxide dismutases (SODs) are important antioxidant enzymes that catalyze the disproportionation of superoxide anion to oxygen and hydrogen peroxide to guard cells against superoxide toxicity. The major pathway for activation of copper/zinc SOD (CSD) involves a copper chaperone for SOD (CCS) and an additional minor CCS-independent pathway reported in mammals. We characterized the CCS-dependent and -independent activation pathways for three CSDs localized in different cellular compartments in Arabidopsis (Arabidopsis thaliana). The main activation pathway for CSD1 in the cytoplasm involved a CCS-dependent and -independent pathway, which was similar to that for human CSD. Activation of CSD2 in chloroplasts depended totally on CCS, similar to yeast (Saccharomyces cerevisiae) CSD. Peroxisome-localized CSD3 via a CCS-independent pathway was similar to nematode (Caenorhabditis elegans) CSD in retaining activity in the absence of CCS. In Arabidopsis, glutathione played a role in CCS-independent activation, as was reported in humans, but an additional factor was required. These findings reveal a highly specific and sophisticated regulation of CSD activation pathways in planta relative to other known CCS-independent activation.

  19. Heat shock protein 90: the cancer chaperone

    Indian Academy of Sciences (India)

    2007-04-02

    Apr 2, 2007 ... Heat shock protein 90 (Hsp90) is a molecular chaperone required for the stability and function of a number of conditionally activated and/or expressed signalling proteins, as well as multiple mutated, chimeric, and/or over-expressed signalling proteins, that promote cancer cell growth and/or survival. Hsp90 ...

  20. The Effects of Platelet-Rich-Plasma (PRP Injection on Ligament Injury

    Directory of Open Access Journals (Sweden)

    Yudhistira Pradnyan Kloping

    2016-04-01

    Full Text Available Background: Soft tissue injuries are becoming a problem especially among active people and athletes, thus doctors are focusing on PRP injection however variety of study results are making the beneficial effects of PRP towards soft tissue healing unclear. The purpose of this study is to clarify the effects of PRP injection on the healing aspect of a ligament injury. Methods: The experimental study used European rabbit (Oryctolagus cuniculus, which was divided into the control and treated group. The 22 samples, ankle ligaments were injured. The treated group was injected with 4 ml PRP taken autologously. On the 2nd day the samples were examined for hematoma. 4 samples from each group were also examined histopathologically. On the 2nd week, the ligament thickness of the remaining samples from each group was examined ultrasonographically. Results: The clinical result showed lower presence of hematoma on the group injected with PRP compared to the control group. The Capillary dilation was less on the treated group compared to the control group. The Inflammatory cells were less on the treated group compared to the control group. The Fibroblasts Cells was less on the treated group compared to the control group. The fibrocytes was more abundant on the treated group compared to the control group. The average of Ligament Thickness was thicker on the treated group compared to the control group. Conclusion: The Injection of PRP is beneficial to a ligament injury based on its effect on enhancing healing on the inflammation, regeneration, and remodeling phases.

  1. The DExD/H-box ATPase Prp2p destabilizes and proofreads the catalytic RNA core of the spliceosome.

    Science.gov (United States)

    Wlodaver, Alissa M; Staley, Jonathan P

    2014-03-01

    After undergoing massive RNA and protein rearrangements during assembly, the spliceosome undergoes a final, more subtle, ATP-dependent rearrangement that is essential for catalysis. This rearrangement requires the DEAH-box protein Prp2p, an RNA-dependent ATPase. Prp2p has been implicated in destabilizing interactions between the spliceosome and the protein complexes SF3 and RES, but a role for Prp2p in destabilizing RNA-RNA interactions has not been explored. Using directed molecular genetics in budding yeast, we have found that a cold-sensitive prp2 mutation is suppressed not only by mutations in SF3 and RES components but also by a range of mutations that disrupt the spliceosomal catalytic core element U2/U6 helix I, which is implicated in juxtaposing the 5' splice site and branch site and in positioning metal ions for catalysis within the context of a putative catalytic triplex; indeed, mutations in this putative catalytic triplex also suppressed a prp2 mutation. Remarkably, we also found that prp2 mutations rescue lethal mutations in U2/U6 helix I. These data provide evidence that RNA elements that comprise the catalytic core are already formed at the Prp2p stage and that Prp2p destabilizes these elements, directly or indirectly, both to proofread spliceosome activation and to promote reconfiguration of the spliceosome to a fully competent, catalytic conformation.

  2. In silico analyses of essential interactions of iminosugars with the Hex A active site and evaluation of their pharmacological chaperone effects for Tay-Sachs disease.

    Science.gov (United States)

    Kato, Atsushi; Nakagome, Izumi; Nakagawa, Shinpei; Kinami, Kyoko; Adachi, Isao; Jenkinson, Sarah F; Désiré, Jérôme; Blériot, Yves; Nash, Robert J; Fleet, George W J; Hirono, Shuichi

    2017-11-15

    The affinity of a series of iminosugar-based inhibitors exhibiting various ring sizes toward Hex A and their essential interactions with the enzyme active site were investigated. All the Hex A-inhibiting iminosugars tested formed hydrogen bonds with Arg178, Asp322, Tyr421 and Glu462 and had the favorable cation-π interaction with Trp460. Among them, DMDP amide (6) proved to be the most potent competitive inhibitor with a Ki value of 0.041 μM. We analyzed the dynamic properties of both DMDP amide (6) and DNJNAc (1) in aqueous solution using molecular dynamics (MD) calculations; the distance of the interaction between Asp322 and 3-OH and Glu323 and 6-OH was important for stable interactions with Hex A, reducing fluctuations in the plasticity of the active site. DMDP amide (6) dose-dependently increased intracellular Hex A activity in the G269S mutant cells and restored Hex A activity up to approximately 43% of the wild type level; this effect clearly exceeded the border line treatment for Tay-Sachs disease, which is regarded as 10-15% of the wild type level. This is a significantly greater effect than that of pyrimethamine, which is currently in Phase 2 clinical trials. DMDP amide (6), therefore, represents a new promising pharmacological chaperone candidate for the treatment of Tay-Sachs disease.

  3. Models for the mechanism for activating copper-zinc superoxide dismutase in the absence of the CCS Cu chaperone in Arabidopsis.

    Science.gov (United States)

    Huang, Chien-Hsun; Kuo, Wen-Yu; Jinn, Tsung-Luo

    2012-03-01

    Copper-zinc superoxide dismutase (CuZnSOD; CSD) is an important antioxidant enzyme for oxidative stress protection. To date, two activation pathways have been identified in many species. One requiring the CCS, Cu chaperone for SOD, to insert Cu and activate CSD (referred to as CCS-dependent pathway), and the other works independently of CCS (referred to as CCS-independent pathway). In our previous study, we suggest an unidentified factor will work with glutathione (GSH) for CSD activation in the absence of the CCS. Here, two models of the CCS-independent mechanism are proposed. The role of the unidentified factor may work as a scaffold protein, which provides a platform for the CSD protein and Cu-GSH to interact, or as a Cu carrier, which itself can bind Cu and interact with CSD proteins. We also suggest that the CSD protein conformation at C-terminal is important in providing a docking site for unidentified factor to access.

  4. Cross-system excision of chaperone-mediated proteolysis in chaperone-assisted recombinant protein production

    Science.gov (United States)

    Martínez-Alonso, Mónica; Villaverde, Antonio

    2010-01-01

    Main Escherichia coli cytosolic chaperones such as DnaK are key components of the control quality network designed to minimize the prevalence of polypeptides with aberrant conformations. This is achieved by both favoring refolding activities but also stimulating proteolytic degradation of folding reluctant species. This last activity is responsible for the decrease of the proteolytic stability of recombinant proteins when co-produced along with DnaK, where an increase in solubility might be associated to a decrease in protein yield. However, when DnaK and its co-chaperone DnaJ are co-produced in cultured insect cells or whole insect larvae (and expectedly, in other heterologous hosts), only positive, folding-related effects of these chaperones are observed, in absence of proteolysis-mediated reduction of recombinant protein yield. PMID:21326941

  5. Structural and functional properties, chaperone activity and posttranslational modifications of alpha-crystallin and its related subunits in the crystalline lens: N-acetylcarnosine, carnosine and carcinine act as alpha- crystallin/small heat shock protein enhancers in prevention and dissolution of cataract in ocular drug delivery formulations of novel therapeutic agents.

    Science.gov (United States)

    Babizhayev, Mark A

    2012-08-01

    Cataract is a leading cause of blindness worldwide and is responsible for ∼40-80% of the estimated 45 million cases of blindness that occur across the globe. In addition to providing refractive properties to the lens for focusing the image, it is believed that the molecular chaperone function of α-crystallin is essential in preventing the light scattering due to aggregation of other proteins and thus in the maintenance of lens transparency and thereby prevention of cataract. By now, it is fairly acknowledged that chaperoning ability of α-crystallin is instrumental in the maintenance of crystalline lens transparency, and decreased chaperone-like activity of α-crystallin is associated with various types and stages of cataract. A better pharmacological targeting of safeguarding the α-crystallin chaperone activity may aid the development of therapeutic strategies that could evade the need for cataract surgery and revive lens transparency of the cataractous lenses. This article originally summarizes the significance of modulation and enhancing of α-crystallin chaperone activity with imidazole-containing dipeptides N-acetylcarnosine, carnosine and carcinine in consequence to prevent, delay or dissolve the human cataract. A growing evidence and discussion of recent patents are presented in this study that demonstrate the ability of N-acetylcarnosine (lubricant eye drops) or carcinine (lubricant eye drops) (universal antioxidant and deglycation agent) resistant to enzymatic hydrolysis with carnosinase to act as pharmacological chaperones, to decrease oxidative stress and ameliorate oxidative and excessive glycation stress-related eye disease phenotypes, suggesting that the field of chaperone therapy might hold novel treatments for age-related cataracts, age-related macular degeneration (AMD) and ocular complications of diabetes (OCD). The therapeutic strategies are highlighted in the study for identifying potential chaperone compounds and for experimentally

  6. Differential modulation of the chaperone-like activity of HSP-1/2, a major protein of horse seminal plasma by anionic and cationic surfactants.

    Science.gov (United States)

    Kumar, C Sudheer; Swamy, Musti J

    2017-03-01

    The major protein of equine seminal plasma, HSP-1/2 exhibits chaperone-like activity (CLA) by protecting various target proteins against thermal, chemical and oxidative stress. Polydispersity and surface hydrophobicity of HSP-1/2 were found to be important for its CLA. Surfactants are known to alter certain properties of proteins, e.g. hydrophobicity, charge and conformation either by altering properties of the medium or by direct binding. In the current study, thermal aggregation of alcohol dehydrogenase (ADH) and enolase has been studied in the presence of HSP-1/2, different surfactants and their combinations. The results obtained show that anionic surfactants (SDS, sodium dodecyl benzene sulfate) and neutral surfactants (tween-20, triton X-100) increase the CLA of HSP-1/2 and also inhibit aggregation of the target proteins independently. On the other hand, cationic surfactants (CTAB, alanine palmityl ester) increased the thermal aggregation of ADH and enolase and also decreased the CLA of HSP-1/2. These results are of significant interest as they show that surfactants such as SDS and tween-20 can potentially be used as anti-aggregation agents to prevent thermal aggregation of target proteins. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Pigeonpea Hybrid-Proline-Rich Protein (CcHyPRP) Confers Biotic and Abiotic Stress Tolerance in Transgenic Rice

    Science.gov (United States)

    Mellacheruvu, Sunitha; Tamirisa, Srinath; Vudem, Dashavantha Reddy; Khareedu, Venkateswara Rao

    2016-01-01

    In this study, we report the overexpression of Cajanus cajan hybrid-proline-rich protein encoding gene (CcHyPRP) in rice which resulted in increased tolerance to both abiotic and biotic stresses. Compared to the control plants, the transgenic rice lines, expressing CcHyPRP, exhibited high-level tolerance against major abiotic stresses, viz., drought, salinity, and heat, as evidenced by increased biomass, chlorophyll content, survival rate, root, and shoot growth. Further, transgenic rice lines showed increased panicle size and grain number compared to the control plants under different stress conditions. The CcHyPRP transgenics, as compared to the control, revealed enhanced activities of catalase and superoxide dismutase (SOD) enzymes and reduced malondialdehyde (MDA) levels. Expression pattern of CcHyPRP::GFP fusion-protein confirmed its predominant localization in cell walls. Moreover, the CcHyPRP transgenics, as compared to the control, exhibited increased resistance to the fungal pathogen Magnaporthe grisea which causes blast disease in rice. Higher levels of bZIP and endochitinase transcripts as well as endochitinase activity were observed in transgenic rice compared to the control plants. The overall results demonstrate the intrinsic role of CcHyPRP in conferring multiple stress tolerance at the whole-plant level. The multipotent CcHyPRP seems promising as a prime candidate gene to fortify crop plants for enhanced tolerance/resistance to different stress factors. PMID:26834756

  8. Proteomic identification of calcium-binding chaperone calreticulin as a potential mediator for the neuroprotective and neuritogenic activities of fruit-derived glycoside amygdalin.

    Science.gov (United States)

    Cheng, Yuanyuan; Yang, Chuanbin; Zhao, Jia; Tse, Hung Fat; Rong, Jianhui

    2015-02-01

    Amygdalin is a fruit-derived glycoside with the potential for treating neurodegenerative diseases. This study was designed to identify the neuroprotective and neuritogenic activities of amygdalin. We initially demonstrated that amygdalin enhanced nerve growth factor (NGF)-induced neuritogenesis and attenuated 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in rat dopaminergic PC12 cells. To define protein targets for amygdalin, we selected a total of 11 mostly regulated protein spots from two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels for protein identification by matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry. We verified the effect of amygdalin on six representative proteins (i.e., calreticulin, Hsp90β, Grp94, 14-3-3η, 14-3-3ζ/δ and Rab GDI-α) for biological relevance to neuronal survival and differentiation. Calcium-binding chaperone calreticulin is of special interest for its activities to promote folding, oligomeric assembly and quality control of proteins that modulate cell survival and differentiation. We transiently knocked down calreticulin expression by specific siRNA and studied its effect on the neuroprotective and neuritogenic activities of amygdalin. We found that amygdalin failed to enhance NGF-induced neuritogenesis in calreticulin-siRNA transfected cells. On the other hand, amygdalin rescued 6-OHDA-induced loss of calreticulin expression. We also found that amygdalin increased the intracellular calcium concentration possibly via inducing calreticulin. Collectively, our results demonstrated the role of calreticulin in mediating the neuroprotective and neuritogenic activities of amygdalin. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. The roles of co-chaperone CCRP/DNAJC7 in Cyp2b10 gene activation and steatosis development in mouse livers.

    Directory of Open Access Journals (Sweden)

    Marumi Ohno

    Full Text Available Cytoplasmic constitutive active/androstane receptor (CAR retention protein (CCRP and also known as DNAJC7 is a co-chaperone previously characterized to retain nuclear receptor CAR in the cytoplasm of HepG2 cells. Here we have produced CCRP knockout (KO mice and demonstrated that CCRP regulates CAR at multiple steps in activation of the cytochrome (Cyp 2b10 gene in liver: nuclear accumulation, RNA polymerase II recruitment and epigenetic modifications. Phenobarbital treatment greatly increased nuclear CAR accumulation in the livers of KO males as compared to those of wild type (WT males. Despite this accumulation, phenobarbital-induced activation of the Cyp2b10 gene was significantly attenuated. In ChIP assays, a CAR/retinoid X receptor-α (RXRα heterodimer binding to the Cyp2b10 promoter was already increased before phenobarbital treatment and further pronounced after treatment. However, RNA polymerase II was barely recruited to the promoter even after phenobarbital treatment. Histone H3K27 on the Cyp2b10 promoter was de-methylated only after phenobarbital treatment in WT but was fully de-methylated before treatment in KO males. Thus, CCRP confers phenobarbital-induced de-methylation capability to the promoter as well as the phenobarbital responsiveness of recruiting RNA polymerase II, but is not responsible for the binding between CAR and its cognate sequence, phenobarbital responsive element module. In addition, KO males developed steatotic livers and increased serum levels of total cholesterol and high density lipoprotein in response to fasting. CCRP appears to be involved in various hepatic regulations far beyond CAR-mediated drug metabolism.

  10. Pharmacological chaperone reshapes the energy landscape for folding and aggregation of the prion protein

    Science.gov (United States)

    Gupta, Amar Nath; Neupane, Krishna; Rezajooei, Negar; Cortez, Leonardo M.; Sim, Valerie L.; Woodside, Michael T.

    2016-06-01

    The development of small-molecule pharmacological chaperones as therapeutics for protein misfolding diseases has proven challenging, partly because their mechanism of action remains unclear. Here we study Fe-TMPyP, a tetrapyrrole that binds to the prion protein PrP and inhibits misfolding, examining its effects on PrP folding at the single-molecule level with force spectroscopy. Single PrP molecules are unfolded with and without Fe-TMPyP present using optical tweezers. Ligand binding to the native structure increases the unfolding force significantly and alters the transition state for unfolding, making it more brittle and raising the barrier height. Fe-TMPyP also binds the unfolded state, delaying native refolding. Furthermore, Fe-TMPyP binding blocks the formation of a stable misfolded dimer by interfering with intermolecular interactions, acting in a similar manner to some molecular chaperones. The ligand thus promotes native folding by stabilizing the native state while also suppressing interactions driving aggregation.

  11. Molecular chaperones and hypoxic-ischemic encephalopathy

    Directory of Open Access Journals (Sweden)

    Cong Hua

    2017-01-01

    Full Text Available Hypoxic-ischemic encephalopathy (HIE is a disease that occurs when the brain is subjected to hypoxia, resulting in neuronal death and neurological deficits, with a poor prognosis. The mechanisms underlying hypoxic-ischemic brain injury include excitatory amino acid release, cellular proteolysis, reactive oxygen species generation, nitric oxide synthesis, and inflammation. The molecular and cellular changes in HIE include protein misfolding, aggregation, and destruction of organelles. The apoptotic pathways activated by ischemia and hypoxia include the mitochondrial pathway, the extrinsic Fas receptor pathway, and the endoplasmic reticulum stress-induced pathway. Numerous treatments for hypoxic-ischemic brain injury caused by HIE have been developed over the last half century. Hypothermia, xenon gas treatment, the use of melatonin and erythropoietin, and hypoxic-ischemic preconditioning have proven effective in HIE patients. Molecular chaperones are proteins ubiquitously present in both prokaryotes and eukaryotes. A large number of molecular chaperones are induced after brain ischemia and hypoxia, among which the heat shock proteins are the most important. Heat shock proteins not only maintain protein homeostasis; they also exert anti-apoptotic effects. Heat shock proteins maintain protein homeostasis by helping to transport proteins to their target destinations, assisting in the proper folding of newly synthesized polypeptides, regulating the degradation of misfolded proteins, inhibiting the aggregation of proteins, and by controlling the refolding of misfolded proteins. In addition, heat shock proteins exert anti-apoptotic effects by interacting with various signaling pathways to block the activation of downstream effectors in numerous apoptotic pathways, including the intrinsic pathway, the endoplasmic reticulum-stress mediated pathway and the extrinsic Fas receptor pathway. Molecular chaperones play a key role in neuroprotection in HIE. In

  12. GmPRP2 promoter drives root-preferential expression in transgenic Arabidopsis and soybean hairy roots.

    Science.gov (United States)

    Chen, Li; Jiang, Bingjun; Wu, Cunxiang; Sun, Shi; Hou, Wensheng; Han, Tianfu

    2014-09-16

    Promoters play important roles in gene expression and function. There are three basic types of promoters: constitutive, specific, and inducible. Constitutive promoters are widely used in genetic engineering, but these promoters have limitations. Inducible promoters are activated by specific inducers. Tissue-specific promoters are a type of specific promoters that drive gene expression in specific tissues or organs. Here, we cloned and characterized the GmPRP2 promoter from soybean. The expression pattern indicated that this promoter is root-preferential in transgenic Arabidopsis and the hairy roots of soybean. It can be used to improve the root resistance or tolerance to pathogens, pests, malnutrition and other abiotic stresses which cause extensive annual losses in soybean production. The GmPRP2 promoter (GmPRP2p-1062) was isolated from soybean cv. Williams 82. Sequence analysis revealed that this promoter contains many cis-acting elements, including root-specific motifs. The GmPRP2p-1062 and its 5'-deletion fragments were fused with the GUS reporter gene and introduced into Arabidopsis and the hairy roots of soybean to further determine promoter activity. Histochemical analysis in transgenic Arabidopsis showed that GUS activity was mainly detected in roots and hypocotyls in all deletion fragments except GmPRP2p-471 (a 5'-deletion fragment of GmPRP2p-1062 with 471 bp length). GUS activity was higher in transgenic Arabidopsis and hairy roots with GmPRP2p-1062 and GmPRP2p-852 (a 5'-deletion fragment of GmPRP2p-1062 with 852 bp length) constructs than the other two constructs. GUS activity was enhanced by NaCl, PEG, IAA and JM treatments and decreased by SA, ABA and GA treatments in transgenic Arabidopsis. GmPRP2p-1062 is a root-preferential promoter, and its core fragment for root-preferential expression might lie between -369 and +1. GmPRP2p-852 may be useful in the genetic engineering of novel soybean cultivars in the future.

  13. UBL/BAG-domain co-chaperones cause cellular stress upon overexpression through constitutive activation of Hsf1

    DEFF Research Database (Denmark)

    Poulsen, Esben Guldahl; Kampmeyer, Caroline; Kriegenburg, Franziska

    2017-01-01

    As a result of exposure to stress conditions, mutations, or defects during synthesis, cellular proteins are prone to misfold. To cope with such partially denatured proteins, cells mount a regulated transcriptional response involving the Hsf1 transcription factor, which drives the synthesis......, binds Bag101 and Bag102 and key residues in the Hsp70 ATPase domains, required for interaction with Bag101 and Bag102, were identified. In humans, BAG-1 overexpression is typically observed in cancers. Overexpression of bag101 and bag102 in fission yeast leads to a strong growth defect caused......, leading to constitutive Hsf1 activation and growth defects....

  14. Nuclear Weapon Personnel Reliability Program (PRP)

    Science.gov (United States)

    1993-05-25

    amphetamines, barbiturates, or other narcotic drugs not prescribed by proper medical authorities, and anabolic steroids shall render an individual...Hallucinogens e. Cannabis f Anabolic Steroids Total C.3. Serious offense decertifications by type (continued) PRP Position Category Crit Cont Crit Cont Crit...States Code (c) DoD Directive 1010.4, "Alcohol and Drug Abuse by C TE. DoD Personnel," August 25, 1980 NO02 1 9 9 3 (d) DoD Directive 5210.56, "Use of

  15. Investigation of modified platelet-rich plasma (mPRP) in promoting the proliferation and differentiation of dental pulp stem cells from deciduous teeth.

    Science.gov (United States)

    Wen, J; Li, H T; Li, S H; Li, X; Duan, J M

    2016-09-01

    Stem cells from human exfoliated deciduous teeth (SHEDs) have great potential to treat various dental-related diseases in regenerative medicine. They are usually maintained with 10% fetal bovine serum (FBS) in vitro. Modified platelet-rich plasma (mPRP) would be a safe alternative to 10% FBS during SHEDs culture. Therefore, our study aimed to compare the proliferation and differentiation of SHEDs cultured in mPRP and FBS medium to explore an optimal concentration of mPRP for SHEDs maintenance. Platelets were harvested by automatic blood cell analyzer and activated by repeated liquid nitrogen freezing and thawing. The platelet-related cytokines were examined and analyzed by ELISA. SHEDs were extracted and cultured with different concentrations of mPRP or 10% FBS medium. Alkaline phosphatase (ALP) activity was measured. Mineralization factors, RUNX2 and OCN, were measured by real-time PCR. SHEDs were characterized with mesenchymal stem cells (MSCs) markers including vimentin, CD44, and CD105. mPRP at different concentrations (2, 5, 10, and 20%) enhanced the growth of SHEDs. Moreover, mPRP significantly stimulated ALP activity and promoted expression of RUNX2 and OCN compared with 10% FBS. mPRP could efficiently facilitate proliferation and differentiation of SHEDs, and 2% mPRP would be an optimal substitute for 10% FBS during SHEDs expansion and differentiation in clinical scale manufacturing.

  16. Investigation of modified platelet-rich plasma (mPRP in promoting the proliferation and differentiation of dental pulp stem cells from deciduous teeth

    Directory of Open Access Journals (Sweden)

    J. Wen

    2016-01-01

    Full Text Available Stem cells from human exfoliated deciduous teeth (SHEDs have great potential to treat various dental-related diseases in regenerative medicine. They are usually maintained with 10% fetal bovine serum (FBS in vitro. Modified platelet-rich plasma (mPRP would be a safe alternative to 10% FBS during SHEDs culture. Therefore, our study aimed to compare the proliferation and differentiation of SHEDs cultured in mPRP and FBS medium to explore an optimal concentration of mPRP for SHEDs maintenance. Platelets were harvested by automatic blood cell analyzer and activated by repeated liquid nitrogen freezing and thawing. The platelet-related cytokines were examined and analyzed by ELISA. SHEDs were extracted and cultured with different concentrations of mPRP or 10% FBS medium. Alkaline phosphatase (ALP activity was measured. Mineralization factors, RUNX2 and OCN, were measured by real-time PCR. SHEDs were characterized with mesenchymal stem cells (MSCs markers including vimentin, CD44, and CD105. mPRP at different concentrations (2, 5, 10, and 20% enhanced the growth of SHEDs. Moreover, mPRP significantly stimulated ALP activity and promoted expression of RUNX2 and OCN compared with 10% FBS. mPRP could efficiently facilitate proliferation and differentiation of SHEDs, and 2% mPRP would be an optimal substitute for 10% FBS during SHEDs expansion and differentiation in clinical scale manufacturing.

  17. Engagement of cellular prion protein with the co-chaperone Hsp70/90 organizing protein regulates the proliferation of glioblastoma stem-like cells.

    Science.gov (United States)

    Iglesia, Rebeca Piatniczka; Prado, Mariana Brandão; Cruz, Lilian; Martins, Vilma Regina; Santos, Tiago Góss; Lopes, Marilene Hohmuth

    2017-04-17

    Glioblastoma (GBM), a highly aggressive brain tumor, contains a subpopulation of glioblastoma stem-like cells (GSCs) that play roles in tumor maintenance, invasion, and therapeutic resistance. GSCs are therefore a promising target for GBM treatment. Our group identified the cellular prion protein (PrP C ) and its partner, the co-chaperone Hsp70/90 organizing protein (HOP), as potential target candidates due to their role in GBM tumorigenesis and in neural stem cell maintenance. GSCs expressing different levels of PrP C were cultured as neurospheres with growth factors, and characterized with stem cells markers and adhesion molecules markers through immunofluorescence and flow cytometry. We than evaluated GSC self-renewal and proliferation by clonal density assays and BrdU incorporation, respectively, in front of recombinant HOP treatment, combined or not with a HOP peptide which mimics the PrP C binding site. Stable silencing of HOP was also performed in parental and/or PrP C -depleted cell populations, and proliferation in vitro and tumor growth in vivo were evaluated. Migration assays were performed on laminin-1 pre-coated glass. We observed that, when GBM cells are cultured as neurospheres, they express specific stemness markers such as CD133, CD15, Oct4, and SOX2; PrP C is upregulated compared to monolayer culture and co-localizes with CD133. PrP C silencing downregulates the expression of molecules associated with cancer stem cells, upregulates markers of cell differentiation and affects GSC self-renewal, pointing to a pivotal role for PrP C in the maintenance of GSCs. Exogenous HOP treatment increases proliferation and self-renewal of GSCs in a PrP C -dependent manner while HOP knockdown disturbs the proliferation process. In vivo, PrP C and/or HOP knockdown potently inhibits the growth of subcutaneously implanted glioblastoma cells. In addition, disruption of the PrP C -HOP complex by a HOP peptide, which mimics the PrP C binding site, affects GSC self

  18. PRP8 inteins in species of the genus Botrytis and other ascomycetes.

    Science.gov (United States)

    Bokor, Annika A M; Kohn, Linda M; Poulter, Russell T M; van Kan, Jan A L

    2012-03-01

    The mobile elements termed inteins have a sporadic distribution in microorganisms. It is unclear how these elements are maintained. Inteins are intervening protein sequences that autocatalytically excise themselves from a precursor. Excision is a post-translational process referred to as 'protein splicing' in which the sequences flanking the intein are ligated, reforming the mature host protein. Some inteins contain a homing endonuclease domain (HEG) that is proposed to facilitate propagation of the intein element within a gene pool. We have previously demonstrated that the HEG of the PRP8 intein is highly active during meiosis in Botrytis cinerea. Here we analysed the Prp8 gene status in 21 additional Botrytis species to obtain insight into the mode of intein inheritance within the Botrytis lineage. Of the 21 species, 15 contained a PRP8 intein whereas six did not. The analysis was extended to closely related (Sclerotiniaceae) and distantly related (Ascomycota) taxa, focussing on evolutionary diversification of the PRP8 intein, including their possible acquisition by horizontal transfer and loss by deletion. Evidence was obtained for the occurrence of genetic footprints of previous intein occupation. There is no compelling evidence of horizontal transfer among species. Three distinct states of the Prp8 allele were identified, distributed over different orders within the Ascomycota: an occupied allele; an empty allele that was never occupied; an empty allele that was presumably previously occupied, from which the intein was precisely deleted. The presence of the genetic footprint identifies 20 species (including Neurospora crassa, Magnaporthe oryzae and Fusarium oxysporum) that previously contained the intein but have lost it entirely, while only 18 species (including Podospora anserina and Fusarium graminearum) appear never to have contained a PRP8 intein. The analysis indicates that inteins may be maintained in an equilibrium state. Copyright © 2012 Elsevier

  19. In Vitro Studies on the Degradability, Bioactivity, and Cell Differentiation of PRP/AZ31B Mg Alloys Composite Scaffold

    Directory of Open Access Journals (Sweden)

    Jian Zou

    2017-01-01

    Full Text Available In recent years, more and more methods have been developed to improve the bioactivity of the biodegradable materials in bone tissue regeneration. In present study, we used rat mesenchymal stem cells (rMSCs to evaluate the outcomes of Mg alloys (AZ31B, Magnesium, and Aluminum and Platelet-rich plasma (PRP/Mg alloys on rMSCs biocompatibility and osteogenic differentiation. Water absorption experiments indicated that both bare AZ31B and PRP/AZ31B were capable of absorbing large amounts of water. But the water absorption ratio for PRP/AZ31B was significantly higher than that for bare AZ31B. The degradability experiments implied that both samples degraded at same speed. rMSCs on the surface of AZ31B distributed more and better than those on the AZ31B scaffold. In ALP activity experiment, the activity of rMSCs on the PRP/AZ31B was markedly higher than that on the AZ31B scaffolds on the 7th day and 14th day. qRT-PCR also showed that OPN and OCN were expressed in both samples. OPN and OCN expression in PRP/AZ31B sample were higher than those in bare AZ31B samples. In summary, the in vitro study implied that AZ31B combined with PRP could remarkably improve cell seeding, attachment, proliferation, and differentiation.

  20. Chaperone-like properties of tobacco plastid thioredoxins f and m

    Science.gov (United States)

    Sanz-Barrio, Ruth; Fernández-San Millán, Alicia; Carballeda, Jon; Corral-Martínez, Patricia; Seguí-Simarro, José M.; Farran, Inmaculada

    2012-01-01

    Thioredoxins (Trxs) are ubiquitous disulphide reductases that play important roles in the redox regulation of many cellular processes. However, some redox-independent functions, such as chaperone activity, have also been attributed to Trxs in recent years. The focus of our study is on the putative chaperone function of the well-described plastid Trxs f and m. To that end, the cDNA of both Trxs, designated as NtTrxf and NtTrxm, was isolated from Nicotiana tabacum plants. It was found that bacterially expressed tobacco Trx f and Trx m, in addition to their disulphide reductase activity, possessed chaperone-like properties. In vitro, Trx f and Trx m could both facilitate the reactivation of the cysteine-free form of chemically denatured glucose-6 phosphate dehydrogenase (foldase chaperone activity) and prevent heat-induced malate dehydrogenase aggregation (holdase chaperone activity). Our results led us to infer that the disulphide reductase and foldase chaperone functions prevail when the proteins occur as monomers and the well-conserved non-active cysteine present in Trx f is critical for both functions. By contrast, the holdase chaperone activity of both Trxs depended on their oligomeric status: the proteins were functional only when they were associated with high molecular mass protein complexes. Because the oligomeric status of both Trxs was induced by salt and temperature, our data suggest that plastid Trxs could operate as molecular holdase chaperones upon oxidative stress, acting as a type of small stress protein. PMID:21948853

  1. Histone chaperone networks shaping chromatin function

    DEFF Research Database (Denmark)

    Hammond, Colin; Strømme, Caroline Bianchi; Huang, Hongda

    2017-01-01

    The association of histones with specific chaperone complexes is important for their folding, oligomerization, post-translational modification, nuclear import, stability, assembly and genomic localization. In this way, the chaperoning of soluble histones is a key determinant of histone availabili...... chaperone network and via co-chaperone complexes to match histone supply with demand, thereby promoting proper nucleosome assembly and maintaining epigenetic information by recycling modified histones evicted from chromatin....

  2. Platlet Rich Plasma (PRP) Improves Fat Grafting Outcomes.

    Science.gov (United States)

    Modarressi, Ali

    2013-01-01

    Autologous fat transfer offers many qualities of a ideal soft tissue filler. Main advantages of fat grafting ensue from the fact that the lipoaspirate tissue is an abundant source of regenerative pluripotential cells. However, the reported rates of fat cell survival vary greatly in the medical literature (10-90%). Different techniques of harvesting, processing, and reinjecting the fat cells are so claimed to be responsible for these differences, without any agreement concerning the best way to process. To address this important disadvantage, we propose the addition of autologous platelet rich plasma (PRP) which is known as a natural reservoir of growth factors stimulating tissue repair and regeneration. This approach is completely autologous and immediately employed without any type of preconditioning. Platelets rich plasma (PRP) preparation included bleeding of 8 ml of blood from patient's peripheral vein in Regen Lab© tubes containing sodium citrate anticoagulant. The whole blood was centrifugated at 1500 g during 3 min. As Regen-tubes contained a special gel separator, 99 % of red blood cells were discarded from the plasma at the bottom of the gel, and >90% of platelets were harvested in 4 ml of plasma on the top of the gel, called the platelet-rich plasma (PRP). The purified fat prepared by Coleman technique was mixed with different amount of PRP for in vitro, in vivo (mice) and clinical experiments: >50% of PRP for skin rejuvenation, superficial scars correction, infraorbital region, ..., and for 20% of PRP with 80% of purified fat for deep filler indication (nasolabial folds, lips, or soft tissue defect). In vitro studies demonstrated that PRP increased fat cells survival rate and stem cells differentiation. Animal models showed that fat graft survival rate was significantly increased by addition of PRP. Several clinical cases confirmed the improvement of wound healing and fat grafting survival in facial reconstruction and aesthetic cases by association of

  3. A Randomized, Controlled Study of DTaP-IPV-HB-PRP-T, a Fully Liquid Hexavalent Vaccine, Administered in a 3-, 5- and 11- to 12-month Schedule.

    Science.gov (United States)

    Vesikari, Timo; Silfverdal, Sven-Arne; Jordanov, Emilia; Feroldi, Emmanuel

    2017-01-01

    To assess the immunogenicity and safety of a fully liquid, ready-to-use hexavalent DTaP-IPV-HB-PRP-T vaccine when administered in a 2 + 1 schedule at 3, 5 and 11-12 months of age. Phase III, randomized, active-controlled, observer-blind, multicenter study. Infants were randomized to receive DTaP-IPV-HB-PRP-T (N = 275) or a licensed control hexavalent vaccine (DTaP-IPV-HB//PRP~T: N = 275), both given in coadministration with Prevenar 13. Serum was analyzed for immune responses to all vaccine antigens. Noninferiority of DTaP-IPV-HB-PRP-T to the control vaccine was tested at completion of the primary series using predefined seroprotection (SP) rate and vaccine response (VR) rates. Safety was assessed using parental reports. Noninferiority of DTaP-IPV-HB-PRP-T to the control vaccine was demonstrated postdose 3 for each antigen, and the SP (for D, T, poliovirus 1, 2 and 3, hepatitis B and polyribosylribitol phosphate) and VR rates (for pertussis toxin and filamentous hemagglutinin) were high in each group. SP rates for D, T, polio 1, 2, 3 and VR rates for pertussis toxin and filamentous hemagglutinin were similar in each group. For hepatitis B, SP rate was slightly higher for DTaP-IPV-HB//PRP~T (99.6%) than DTaP-IPV-HB-PRP-T (96.4%), and for PRP, SP rate was higher for DTaP-IPV-HB-PRP-T (93.5%) than DTaP-IPV-HB//PRP~T (85.2%). For Prevenar 13, the SP rate was high for each serotype and similar for both groups. All vaccines were well tolerated. These study findings confirm the safety and immunogenicity and thus the suitability of this fully liquid hexavalent vaccine for administration in a 2 + 1 schedule.

  4. OSU‐03012 and Viagra Treatment Inhibits the Activity of Multiple Chaperone Proteins and Disrupts the Blood–Brain Barrier: Implications for Anti‐Cancer Therapies

    Science.gov (United States)

    Booth, Laurence; Roberts, Jane L.; Tavallai, Mehrad; Nourbakhsh, Aida; Chuckalovcak, John; Carter, Jori; Poklepovic, Andrew

    2015-01-01

    We examined the interaction between OSU‐03012 (also called AR‐12) with phosphodiesterase 5 (PDE5) inhibitors to determine the role of the chaperone glucose‐regulated protein (GRP78)/BiP/HSPA5 in the cellular response. Sildenafil (Viagra) interacted in a greater than additive fashion with OSU‐03012 to kill stem‐like GBM cells. Treatment of cells with OSU‐03012/sildenafil: abolished the expression of multiple oncogenic growth factor receptors and plasma membrane drug efflux pumps and caused a rapid degradation of GRP78 and other HSP70 and HSP90 family chaperone proteins. Decreased expression of plasma membrane receptors and drug efflux pumps was dependent upon enhanced PERK‐eIF2α‐ATF4‐CHOP signaling and was blocked by GRP78 over‐expression. In vivo OSU‐03012/sildenafil was more efficacious than treatment with celecoxib and sildenafil at killing tumor cells without damaging normal tissues and in parallel reduced expression of ABCB1 and ABCG2 in the normal brain. The combination of OSU‐03012/sildenafil synergized with low concentrations of sorafenib to kill tumor cells, and with lapatinib to kill ERBB1 over‐expressing tumor cells. In multiplex assays on plasma and human tumor tissue from an OSU‐03012/sildenafil treated mouse, we noted a profound reduction in uPA signaling and identified FGF and JAK1/2 as response biomarkers for potentially suppressing the killing response. Inhibition of FGFR signaling and to a lesser extent JAK1/2 signaling profoundly enhanced OSU‐03012/sildenafil lethality. J. Cell. Physiol. 230: 1982–1998, 2015. © 2015 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc. PMID:25736380

  5. Indole and synthetic derivative activate chaperone expression to reduce polyQ aggregation in SCA17 neuronal cell and slice culture models

    Directory of Open Access Journals (Sweden)

    Kung PJ

    2014-10-01

    Full Text Available Pin-Jui Kung,1,* Yu-Chen Tao,1,* Ho-Chiang Hsu,1 Wan-Ling Chen,1 Te-Hsien Lin,1 Donala Janreddy,2 Ching-Fa Yao,2 Kuo-Hsuan Chang,3 Jung-Yaw Lin,1 Ming-Tsan Su,1 Chung-Hsin Wu,1 Guey-Jen Lee-Chen,1 Hsiu-Mei Hsieh-Li1 1Department of Life Science, 2Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan; 3Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei, Taiwan *These authors contributed equally to this work Abstract: In spinocerebellar ataxia type 17 (SCA17, the expansion of a translated CAG repeat in the TATA box binding protein (TBP gene results in a long polyglutamine (polyQ tract in the TBP protein, leading to intracellular accumulation of aggregated TBP and cell death. The molecular chaperones act in preventing protein aggregation to ameliorate downstream harmful events. In this study, we used Tet-On SH-SY5Y cells with inducible SCA17 TBP/Q79-green fluorescent protein (GFP expression to test indole and synthetic derivative NC001-8 for neuroprotection. We found that indole and NC001-8 up-regulated chaperone expression to reduce polyQ aggregation in neuronal differentiated TBP/Q79 cells. The effects on promoting neurite outgrowth and on reduction of aggregation on Purkinje cells were also confirmed with cerebellar primary and slice cultures of SCA17 transgenic mice. Our results demonstrate how indole and derivative NC001-8 reduce polyQ aggregation to support their therapeutic potentials in SCA17 treatment. Keywords: spinocerebellar ataxia type 17, TATA box binding protein, polyQ aggregation, indole and derivative, therapeutics

  6. Structural Bioinformatics and Protein Docking Analysis of the Molecular Chaperone-Kinase Interactions: Towards Allosteric Inhibition of Protein Kinases by Targeting the Hsp90-Cdc37 Chaperone Machinery

    Directory of Open Access Journals (Sweden)

    Gennady Verkhivker

    2013-11-01

    Full Text Available A fundamental role of the Hsp90-Cdc37 chaperone system in mediating maturation of protein kinase clients and supporting kinase functional activity is essential for the integrity and viability of signaling pathways involved in cell cycle control and organism development. Despite significant advances in understanding structure and function of molecular chaperones, the molecular mechanisms and guiding principles of kinase recruitment to the chaperone system are lacking quantitative characterization. Structural and thermodynamic characterization of Hsp90-Cdc37 binding with protein kinase clients by modern experimental techniques is highly challenging, owing to a transient nature of chaperone-mediated interactions. In this work, we used experimentally-guided protein docking to probe the allosteric nature of the Hsp90-Cdc37 binding with the cyclin-dependent kinase 4 (Cdk4 kinase clients. The results of docking simulations suggest that the kinase recognition and recruitment to the chaperone system may be primarily determined by Cdc37 targeting of the N-terminal kinase lobe. The interactions of Hsp90 with the C-terminal kinase lobe may provide additional “molecular brakes” that can lock (or unlock kinase from the system during client loading (release stages. The results of this study support a central role of the Cdc37 chaperone in recognition and recruitment of the kinase clients. Structural analysis may have useful implications in developing strategies for allosteric inhibition of protein kinases by targeting the Hsp90-Cdc37 chaperone machinery.

  7. Hsp100/ClpB Chaperone Function and Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Vierling, Elizabeth [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Biochemistry and Molecular Biology

    2015-01-27

    The supported research investigated the mechanism of action of a unique class of molecular chaperones in higher plants, the Hsp100/ClpB proteins, with the ultimate goal of defining how these chaperones influence plant growth, development, stress tolerance and productivity. Molecular chaperones are essential effectors of cellular “protein quality control”, which comprises processes that ensure the proper folding, localization, activation and turnover of proteins. Hsp100/ClpB proteins are required for temperature acclimation in plants, optimal seed yield, and proper chloroplast development. The model plant Arabidopsis thaliana and genetic and molecular approaches were used to investigate two of the three members of the Hsp100/ClpB proteins in plants, cytosolic AtHsp101 and chloroplast-localized AtClpB-p. Investigating the chaperone activity of the Hsp100/ClpB proteins addresses DOE goals in that this activity impacts how “plants generate and assemble components” as well as “allowing for their self repair”. Additionally, Hsp100/ClpB protein function in plants is directly required for optimal “utilization of biological energy” and is involved in “mechanisms that control the architecture of energy transduction systems”.

  8. Endoplasmic reticulum chaperones and their roles in the immunogenicity of cancer vaccines

    Directory of Open Access Journals (Sweden)

    Michael William Graner

    2015-01-01

    Full Text Available The endoplasmic reticulum (ER is a major site of passage for proteins en route to other organelles, to the cell surface, and to the extracellular space. It is also the transport route for peptides generated in the cytosol by the proteasome into the ER for loading onto major histocompatibility complex class I (MHC I molecules for eventual antigen presentation at the cell surface. Chaperones within the ER are critical for many of these processes; however, outside the ER certain of those chaperones may play important and direct roles in immune responses. In some cases, particular ER chaperones have been utilized as vaccines against tumors or infectious disease pathogens when purified from tumor tissue or recombinantly generated and loaded with antigen. In other cases, the cell surface location of ER chaperones has implications for immune responses as well as possible tumor resistance. We have produced heat shock protein/chaperone protein-based cancer vaccines called CRCL (Chaperone-Rich Cell Lysate that are conglomerates of chaperones enriched from solid tumors by an isoelectric focusing technique. These preparations have been effective against numerous murine tumors, as well as in a canine with an advanced lung carcinoma treated with autologous CRCL. We also published extensive proteomic analyses of CRCL prepared from human surgically-resected tumor samples. Of note, these preparations contained at least ten ER chaperones and a number of other residents, along with many other chaperones/heat shock proteins. Gene ontology and network analyses utilizing these proteins essentially recapitulate the antigen presentation pathways and interconnections. In conjunction with our current knowledge of cell surface/extracellular ER chaperones, these data collectively suggest that a systems-level view may provide insight into the potent immune stimulatory activities of CRCL with an emphasis on the roles of ER components in those processes.

  9. ESAT-6 from Mycobacterium tuberculosis dissociates from its putative chaperone CFP-10 under acidic conditions and exhibits membrane-lysing activity.

    Science.gov (United States)

    de Jonge, Marien I; Pehau-Arnaudet, Gérard; Fretz, Marjan M; Romain, Felix; Bottai, Daria; Brodin, Priscille; Honoré, Nadine; Marchal, Gilles; Jiskoot, Wim; England, Patrick; Cole, Stewart T; Brosch, Roland

    2007-08-01

    The 6-kDa early secreted antigenic target ESAT-6 and the 10-kDa culture filtrate protein CFP-10 of Mycobacterium tuberculosis are secreted by the ESX-1 system into the host cell and thereby contribute to pathogenicity. Although different studies performed at the organismal and cellular levels have helped to explain ESX-1-associated phenomena, not much is known about how ESAT-6 and CFP-10 contribute to pathogenesis at the molecular level. In this study we describe the interaction of both proteins with lipid bilayers, using biologically relevant liposomal preparations containing dimyristoylphosphatidylcholine (DMPC), dimyristoylphosphatidylglycerol, and cholesterol. Using flotation gradient centrifugation, we demonstrate that ESAT-6 showed strong association with liposomes, and in particular with preparations containing DMPC and cholesterol, whereas the interaction of CFP-10 with membranes appeared to be weaker and less specific. Most importantly, binding to the biomembranes no longer occurred when the proteins were present as a 1:1 ESAT-6.CFP-10 complex. However, lowering of the pH resulted in dissociation of the protein complex and subsequent protein-liposome interaction. Finally, cryoelectron microscopy revealed that ESAT-6 destabilized and lysed liposomes, whereas CFP-10 did not. In conclusion, we propose that one of the main features of ESAT-6 in the infection process of M. tuberculosis is the interaction with biomembranes that occurs after dissociation from its putative chaperone CFP-10 under acidic conditions typically encountered in the phagosome.

  10. Structural model of dodecameric heat-shock protein Hsp21: Flexible N-terminal arms interact with client proteins while C-terminal tails maintain the dodecamer and chaperone activity.

    Science.gov (United States)

    Rutsdottir, Gudrun; Härmark, Johan; Weide, Yoran; Hebert, Hans; Rasmussen, Morten I; Wernersson, Sven; Respondek, Michal; Akke, Mikael; Højrup, Peter; Koeck, Philip J B; Söderberg, Christopher A G; Emanuelsson, Cecilia

    2017-05-12

    Small heat-shock proteins (sHsps) prevent aggregation of thermosensitive client proteins in a first line of defense against cellular stress. The mechanisms by which they perform this function have been hard to define due to limited structural information; currently, there is only one high-resolution structure of a plant sHsp published, that of the cytosolic Hsp16.9. We took interest in Hsp21, a chloroplast-localized sHsp crucial for plant stress resistance, which has even longer N-terminal arms than Hsp16.9, with a functionally important and conserved methionine-rich motif. To provide a framework for investigating structure-function relationships of Hsp21 and understanding these sequence variations, we developed a structural model of Hsp21 based on homology modeling, cryo-EM, cross-linking mass spectrometry, NMR, and small-angle X-ray scattering. Our data suggest a dodecameric arrangement of two trimer-of-dimer discs stabilized by the C-terminal tails, possibly through tail-to-tail interactions between the discs, mediated through extended IXVXI motifs. Our model further suggests that six N-terminal arms are located on the outside of the dodecamer, accessible for interaction with client proteins, and distinct from previous undefined or inwardly facing arms. To test the importance of the IXVXI motif, we created the point mutant V181A, which, as expected, disrupts the Hsp21 dodecamer and decreases chaperone activity. Finally, our data emphasize that sHsp chaperone efficiency depends on oligomerization and that client interactions can occur both with and without oligomer dissociation. These results provide a generalizable workflow to explore sHsps, expand our understanding of sHsp structural motifs, and provide a testable Hsp21 structure model to inform future investigations. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Catalysis of protein folding by chaperones accelerates evolutionary dynamics in adapting cell populations.

    Directory of Open Access Journals (Sweden)

    Murat Cetinbaş

    Full Text Available Although molecular chaperones are essential components of protein homeostatic machinery, their mechanism of action and impact on adaptation and evolutionary dynamics remain controversial. Here we developed a physics-based ab initio multi-scale model of a living cell for population dynamics simulations to elucidate the effect of chaperones on adaptive evolution. The 6-loci genomes of model cells encode model proteins, whose folding and interactions in cellular milieu can be evaluated exactly from their genome sequences. A genotype-phenotype relationship that is based on a simple yet non-trivially postulated protein-protein interaction (PPI network determines the cell division rate. Model proteins can exist in native and molten globule states and participate in functional and all possible promiscuous non-functional PPIs. We find that an active chaperone mechanism, whereby chaperones directly catalyze protein folding, has a significant impact on the cellular fitness and the rate of evolutionary dynamics, while passive chaperones, which just maintain misfolded proteins in soluble complexes have a negligible effect on the fitness. We find that by partially releasing the constraint on protein stability, active chaperones promote a deeper exploration of sequence space to strengthen functional PPIs, and diminish the non-functional PPIs. A key experimentally testable prediction emerging from our analysis is that down-regulation of chaperones that catalyze protein folding significantly slows down the adaptation dynamics.

  12. Insight into the assembly of chaperones

    Energy Technology Data Exchange (ETDEWEB)

    May, R.P. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Stegmann, R.; Manakova, E.; Roessle, M.; Hermann, T.; Heumann, H. [Max-Planck-Institut fuer Biochemie, Martinsried (Germany); Axmann, S.; Plueckthun, A. [Zurich Univ. (Switzerland); Wiedenmann, A. [HMI, Berlin (Germany)

    1997-04-01

    Chaperones are proteins that help other proteins (substrate proteins) to acquire a `good` conformation. The folding is a dynamic process and involves repetitive binding and release of the chaperone components and of the substrate protein. Small-angle neutron scattering is used to investigate the structural changes that appear to happen during the folding process. (author). 2 refs.

  13. Copper transporters and chaperones: Their function on ...

    Indian Academy of Sciences (India)

    Copper, although known as a micronutrient, has a pivotal role in modulating the cellular metabolism. Many studieshave reported the role of copper in angiogenesis. Copper chaperones are intracellular proteins that mediate coppertrafficking to various cell organelles. However, the role and function of copper chaperones in ...

  14. Molecular chaperones: guardians of the proteome in normal and disease states [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Wilson Jeng

    2015-12-01

    Full Text Available Proteins must adopt a defined three-dimensional structure in order to gain functional activity, or must they? An ever-increasing number of intrinsically disordered proteins and amyloid-forming polypeptides challenge this dogma. While molecular chaperones and proteases are traditionally associated with protein quality control inside the cell, it is now apparent that molecular chaperones not only promote protein folding in the “forward” direction by facilitating folding and preventing misfolding and aggregation, but also facilitate protein unfolding and even disaggregation resulting in the recovery of functional protein from aggregates. Here, we review our current understanding of ATP-dependent molecular chaperones that harness the energy of ATP binding and hydrolysis to fuel their chaperone functions. An emerging theme is that most of these chaperones do not work alone, but instead function together with other chaperone systems to maintain the proteome. Hence, molecular chaperones are the major component of the proteostasis network that guards and protects the proteome from damage. Furthermore, while a decline of this network is detrimental to cell and organismal health, a controlled perturbation of the proteostasis network may offer new therapeutic avenues against human diseases.

  15. Microbicidal properties of Leukocyte- and Platelet-Rich Plasma/Fibrin (L-PRP/L-PRF): new perspectives.

    Science.gov (United States)

    Cieslik-Bielecka, A; Dohan Ehrenfest, D M; Lubkowska, A; Bielecki, T

    2012-01-01

    Platelets, as main actors of the first stage of the healing process, play an important role in tissue repair. Their granules contain many active substances, particularly over 30 growth factors with significant effects on the resident cells at the site of injury, such as mesenchymal stem cells, chondrocytes, fibroblasts, osteoblasts. This potential may be increased by the concentration of the platelets, using platelet-rich plasma/fibrin products. In the four families of platelet concentrates, 2 families contain also significant concentrations of leukocytes: L-PRP (Leukocyte- and Platelet-Rich Plasma) and L-PRF (Leukocyte- and Platelet-Rich Fibrin). Inductive properties of platelet concentrates were widely described. However, they present also antimicrobial effects. The antibacterial effects of L-PRP were highlighted in only a few in vitro studies. Strong activity comparable to gentamicin and oxacillin for L-PRP against methicillin susceptible Staphylococcus aureus (MSSA) was already demonstrated. L-PRP also inhibited the growth of methicillin resistant Staphylococcus aureus (MRSA) and Escherichia coli. Some authors also reported clinical observations about the reduction of infections and the induction of healing processes after the use of platelet concentrates in cardiac, orthopaedic, oral and maxillofacial surgery. However, very little is yet known about the antibacterial effects of these concentrates. In this manuscript, the current data about the antimicrobial agents and cells present in the platelet-rich plasma/fibrin are highlighted and discussed, in order to introduce this new key chapter of the platelet concentrate technology history.

  16. Phosphorylation-mediated control of histone chaperone ASF1 levels by tousled-like kinases

    OpenAIRE

    Maxim Pilyugin; Jeroen Demmers; Peter Verrijzer, C.; Francois Karch; Moshkin, Yuri M.

    2009-01-01

    textabstractHistone chaperones are at the hub of a diverse interaction networks integrating a plethora of chromatin modifying activities. Histone H3/H4 chaperone ASF1 is a target for cell-cycle regulated Tousled-like kinases (TLKs) and both proteins cooperate during chromatin replication. However, the precise role of post-translational modification of ASF1 remained unclear. Here, we identify the TLK phosphorylation sites for both Drosophila and human ASF1 proteins. Loss of TLK- mediated phosp...

  17. Na+/K+-ATPase is present in scrapie-associated fibrils, modulates PrP misfolding in vitro and links PrP function and dysfunction.

    Directory of Open Access Journals (Sweden)

    James F Graham

    Full Text Available Transmissible spongiform encephalopathies are characterised by widespread deposition of fibrillar and/or plaque-like forms of the prion protein. These aggregated forms are produced by misfolding of the normal prion protein, PrP(C, to the disease-associated form, PrP(Sc, through mechanisms that remain elusive but which require either direct or indirect interaction between PrP(C and PrP(Sc isoforms. A wealth of evidence implicates other non-PrP molecules as active participants in the misfolding process, to catalyse and direct the conformational conversion of PrP(C or to provide a scaffold ensuring correct alignment of PrP(C and PrP(Sc during conversion. Such molecules may be specific to different scrapie strains to facilitate differential prion protein misfolding. Since molecular cofactors may become integrated into the growing protein fibril during prion conversion, we have investigated the proteins contained in prion disease-specific deposits by shotgun proteomics of scrapie-associated fibrils (SAF from mice infected with 3 different strains of mouse-passaged scrapie. Concomitant use of negative control preparations allowed us to identify and discount proteins that are enriched non-specifically by the SAF isolation protocol. We found several proteins that co-purified specifically with SAF from infected brains but none of these were reproducibly and demonstrably specific for particular scrapie strains. The α-chain of Na(+/K(+-ATPase was common to SAF from all 3 strains and we tested the ability of this protein to modulate in vitro misfolding of recombinant PrP. Na(+/K(+-ATPase enhanced the efficiency of disease-specific conversion of recombinant PrP suggesting that it may act as a molecular cofactor. Consistent with previous results, the same protein inhibited fibrillisation kinetics of recombinant PrP. Since functional interactions between PrP(C and Na(+/K(+-ATPase have previously been reported in astrocytes, our data highlight this molecule as

  18. PRP: The Proven Solution for Cleaning Up Oil Spills

    Science.gov (United States)

    2006-01-01

    The basic technology behind PRP is thousands of microcapsules, tiny balls of beeswax with hollow centers. Water cannot penetrate the microcapsule s cell, but oil is absorbed right into the beeswax spheres as they float on the water s surface. This way, the contaminants, chemical compounds that originally come from crude oil such as fuels, motor oils, or petroleum hydrocarbons, are caught before they settle. PRP works well as a loose powder for cleaning up contaminants in lakes and other ecologically fragile areas. The powder can be spread over a contaminated body of water or soil, and it will absorb contaminants, contain them in isolation, and dispose of them safely. In water, it is important that PRP floats and keeps the oil on the surface, because, even if oil exposure is not immediately lethal, it can cause long-term harm if allowed to settle. Bottom-dwelling fish exposed to compounds released after oil spills may develop liver disease, in addition to reproductive and growth problems. This use of PRP is especially effective for environmental cleanup in sensitive areas like coral reefs and mangroves.

  19. The Prp19 complex directly functions in mitotic spindle assembly.

    Science.gov (United States)

    Hofmann, Jennifer C; Tegha-Dunghu, Justus; Dräger, Stefanie; Will, Cindy L; Lührmann, Reinhard; Gruss, Oliver J

    2013-01-01

    The conserved Prp19 (pre-RNA processing 19) complex is required for pre-mRNA splicing in eukaryotic nuclei. Recent RNAi screens indicated that knockdown of Prp19 complex subunits strongly delays cell proliferation. Here we show that knockdown of the smallest subunit, BCAS2/Spf27, destabilizes the entire complex and leads to specific mitotic defects in human cells. These could result from splicing failures in interphase or reflect a direct function of the complex in open mitosis. Using Xenopus extracts, in which cell cycle progression and spindle formation can be reconstituted in vitro, we tested Prp19 complex functions during a complete cell cycle and directly in open mitosis. Strikingly, immunodepletion of the complex either before or after interphase significantly reduces the number of intact spindles, and increases the percentage of spindles with lower microtubule density and impaired metaphase alignment of chromosomes. Our data identify the Prp19 complex as the first spliceosome subcomplex that directly contributes to mitosis in vertebrates independently of its function in interphase.

  20. The Prp19 complex directly functions in mitotic spindle assembly.

    Directory of Open Access Journals (Sweden)

    Jennifer C Hofmann

    Full Text Available The conserved Prp19 (pre-RNA processing 19 complex is required for pre-mRNA splicing in eukaryotic nuclei. Recent RNAi screens indicated that knockdown of Prp19 complex subunits strongly delays cell proliferation. Here we show that knockdown of the smallest subunit, BCAS2/Spf27, destabilizes the entire complex and leads to specific mitotic defects in human cells. These could result from splicing failures in interphase or reflect a direct function of the complex in open mitosis. Using Xenopus extracts, in which cell cycle progression and spindle formation can be reconstituted in vitro, we tested Prp19 complex functions during a complete cell cycle and directly in open mitosis. Strikingly, immunodepletion of the complex either before or after interphase significantly reduces the number of intact spindles, and increases the percentage of spindles with lower microtubule density and impaired metaphase alignment of chromosomes. Our data identify the Prp19 complex as the first spliceosome subcomplex that directly contributes to mitosis in vertebrates independently of its function in interphase.

  1. Platelet-rich plasma (PRP) for knee disorders

    Science.gov (United States)

    Shahid, Mohammad; Kundra, Rik

    2017-01-01

    Platelet-rich plasma (PRP) is an autologous blood product with platelet concentrations above baseline values. The process involves the extraction of blood from the patient which is then centrifuged to obtain a concentrated suspension of platelets by plasmapheresis. It then undergoes a two-stage centrifugation process to separate the solid and liquid components of the anticoagulated blood. PRP owes its therapeutic use to the growth factors released by the platelets which are claimed to possess multiple regenerative properties. In the knee, PRP has been used in patients with articular cartilage pathology, ligamentous and meniscal injuries. There is a growing body of evidence to support its use in selected indications and this review looks at the most recent evidence. We also look at the current UK National Institute of Health & Clinical Excellence (NICE) guidelines with respect to osteoarthritis and the use of PRP in the knee. Cite this article: EFORT Open Rev 2017;2:28–34. DOI: 10.1302/2058-5241.2.160004. PMID:28607768

  2. Do autologous blood and PRP injections effectively treat tennis elbow?

    Science.gov (United States)

    Widstrom, Luke; Slattengren, Andrew

    2016-09-01

    Both approaches reduce pain, but the improvement with platelet-rich plasma (PRP) is not clinically meaningful. Autologous blood injections (ABIs) are more effective than corticosteroid injections for reducing pain and disability in patients with tennis elbow in both the short and long term.

  3. Probing molecular mechanisms of the Hsp90 chaperone: biophysical modeling identifies key regulators of functional dynamics.

    Directory of Open Access Journals (Sweden)

    Anshuman Dixit

    Full Text Available Deciphering functional mechanisms of the Hsp90 chaperone machinery is an important objective in cancer biology aiming to facilitate discovery of targeted anti-cancer therapies. Despite significant advances in understanding structure and function of molecular chaperones, organizing molecular principles that control the relationship between conformational diversity and functional mechanisms of the Hsp90 activity lack a sufficient quantitative characterization. We combined molecular dynamics simulations, principal component analysis, the energy landscape model and structure-functional analysis of Hsp90 regulatory interactions to systematically investigate functional dynamics of the molecular chaperone. This approach has identified a network of conserved regions common to the Hsp90 chaperones that could play a universal role in coordinating functional dynamics, principal collective motions and allosteric signaling of Hsp90. We have found that these functional motifs may be utilized by the molecular chaperone machinery to act collectively as central regulators of Hsp90 dynamics and activity, including the inter-domain communications, control of ATP hydrolysis, and protein client binding. These findings have provided support to a long-standing assertion that allosteric regulation and catalysis may have emerged via common evolutionary routes. The interaction networks regulating functional motions of Hsp90 may be determined by the inherent structural architecture of the molecular chaperone. At the same time, the thermodynamics-based "conformational selection" of functional states is likely to be activated based on the nature of the binding partner. This mechanistic model of Hsp90 dynamics and function is consistent with the notion that allosteric networks orchestrating cooperative protein motions can be formed by evolutionary conserved and sparsely connected residue clusters. Hence, allosteric signaling through a small network of distantly connected

  4. Probing molecular mechanisms of the Hsp90 chaperone: biophysical modeling identifies key regulators of functional dynamics.

    Science.gov (United States)

    Dixit, Anshuman; Verkhivker, Gennady M

    2012-01-01

    Deciphering functional mechanisms of the Hsp90 chaperone machinery is an important objective in cancer biology aiming to facilitate discovery of targeted anti-cancer therapies. Despite significant advances in understanding structure and function of molecular chaperones, organizing molecular principles that control the relationship between conformational diversity and functional mechanisms of the Hsp90 activity lack a sufficient quantitative characterization. We combined molecular dynamics simulations, principal component analysis, the energy landscape model and structure-functional analysis of Hsp90 regulatory interactions to systematically investigate functional dynamics of the molecular chaperone. This approach has identified a network of conserved regions common to the Hsp90 chaperones that could play a universal role in coordinating functional dynamics, principal collective motions and allosteric signaling of Hsp90. We have found that these functional motifs may be utilized by the molecular chaperone machinery to act collectively as central regulators of Hsp90 dynamics and activity, including the inter-domain communications, control of ATP hydrolysis, and protein client binding. These findings have provided support to a long-standing assertion that allosteric regulation and catalysis may have emerged via common evolutionary routes. The interaction networks regulating functional motions of Hsp90 may be determined by the inherent structural architecture of the molecular chaperone. At the same time, the thermodynamics-based "conformational selection" of functional states is likely to be activated based on the nature of the binding partner. This mechanistic model of Hsp90 dynamics and function is consistent with the notion that allosteric networks orchestrating cooperative protein motions can be formed by evolutionary conserved and sparsely connected residue clusters. Hence, allosteric signaling through a small network of distantly connected residue clusters may be

  5. The Role of Co-chaperones in Synaptic Proteostasis and Neurodegenerative Disease

    Directory of Open Access Journals (Sweden)

    Erica L. Gorenberg

    2017-05-01

    Full Text Available Synapses must be preserved throughout an organism's lifespan to allow for normal brain function and behavior. Synapse maintenance is challenging given the long distances between the termini and the cell body, reliance on axonal transport for delivery of newly synthesized presynaptic proteins, and high rates of synaptic vesicle exo- and endocytosis. Hence, synapses rely on efficient proteostasis mechanisms to preserve their structure and function. To this end, the synaptic compartment has specific chaperones to support its functions. Without proper synaptic chaperone activity, local proteostasis imbalances lead to neurotransmission deficits, dismantling of synapses, and neurodegeneration. In this review, we address the roles of four synaptic chaperones in the maintenance of the nerve terminal, as well as their genetic links to neurodegenerative disease. Three of these are Hsp40 co-chaperones (DNAJs: Cysteine String Protein alpha (CSPα; DNAJC5, auxilin (DNAJC6, and Receptor-Mediated Endocytosis 8 (RME-8; DNAJC13. These co-chaperones contain a conserved J domain through which they form a complex with heat shock cognate 70 (Hsc70, enhancing the chaperone's ATPase activity. CSPα is a synaptic vesicle protein known to chaperone the t-SNARE SNAP-25 and the endocytic GTPase dynamin-1, thereby regulating synaptic vesicle exocytosis and endocytosis. Auxilin binds assembled clathrin cages, and through its interactions with Hsc70 leads to the uncoating of clathrin-coated vesicles, a process necessary for the regeneration of synaptic vesicles. RME-8 is a co-chaperone on endosomes and may have a role in clathrin-coated vesicle endocytosis on this organelle. These three co-chaperones maintain client function by preserving folding and assembly to prevent client aggregation, but they do not break down aggregates that have already formed. The fourth synaptic chaperone we will discuss is Heat shock protein 110 (Hsp110, which interacts with Hsc70, DNAJAs, and

  6. Peptide binding specificity of the chaperone calreticulin

    DEFF Research Database (Denmark)

    Sandhu, N.; Duus, K.; Jorgensen, C.S.

    2007-01-01

    Calreticulin is a molecular chaperone with specificity for polypeptides and N-linked monoglucosylated glycans. In order to determine the specificity of polypeptide binding, the interaction of calreticulin with polypeptides was investigated using synthetic peptides of different length and composit...

  7. From Chaperones to the Membrane with a BAM!

    Science.gov (United States)

    Plummer, Ashlee M; Fleming, Karen G

    2016-10-01

    Outer membrane proteins (OMPs) play a central role in the integrity of the outer membrane of Gram-negative bacteria. Unfolded OMPs (uOMPs) transit across the periplasm, and subsequent folding and assembly are crucial for biogenesis. Chaperones and the essential β-barrel assembly machinery (BAM) complex facilitate these processes. In vitro studies suggest that some chaperones sequester uOMPs in internal cavities during their periplasmic transit to prevent deleterious aggregation. Upon reaching the outer membrane, the BAM complex acts catalytically to accelerate uOMP folding. Complementary in vivo experiments have revealed the localization and activity of the BAM complex in living cells. Completing an understanding of OMP biogenesis will require a holistic view of the interplay among the individual components discussed here. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Ambroxol chaperone therapy for neuronopathic Gaucher disease: A pilot study.

    Science.gov (United States)

    Narita, Aya; Shirai, Kentarou; Itamura, Shinji; Matsuda, Atsue; Ishihara, Akiko; Matsushita, Kumi; Fukuda, Chisako; Kubota, Norika; Takayama, Rumiko; Shigematsu, Hideo; Hayashi, Anri; Kumada, Tomohiro; Yuge, Kotaro; Watanabe, Yoriko; Kosugi, Saori; Nishida, Hiroshi; Kimura, Yukiko; Endo, Yusuke; Higaki, Katsumi; Nanba, Eiji; Nishimura, Yoko; Tamasaki, Akiko; Togawa, Masami; Saito, Yoshiaki; Maegaki, Yoshihiro; Ohno, Kousaku; Suzuki, Yoshiyuki

    2016-03-01

    Gaucher disease (GD) is a lysosomal storage disease characterized by a deficiency of glucocerebrosidase. Although enzyme-replacement and substrate-reduction therapies are available, their efficacies in treating the neurological manifestations of GD are negligible. Pharmacological chaperone therapy is hypothesized to offer a new strategy for treating the neurological manifestations of this disease. Specifically, ambroxol, a commonly used expectorant, has been proposed as a candidate pharmacological chaperone. The purpose of this study was to evaluate the safety, tolerability, and neurological efficacy of ambroxol in patients with neuronopathic GD. This open-label pilot study included five patients who received high-dose oral ambroxol in combination with enzyme replacement therapy. Safety was assessed by adverse event query, physical examination, electrocardiography, laboratory studies, and drug concentration. Biochemical efficacy was assessed through evidence of glucocerebrosidase activity in the lymphocytes and glucosylsphingosine levels in the cerebrospinal fluid. Neurological efficacy was evaluated using the Unified Myoclonus Rating Scale, Gross Motor Function Measure, Functional Independence Measure, seizure frequency, pupillary light reflex, horizontal saccadic latency, and electrophysiologic studies. High-dose oral ambroxol had good safety and tolerability, significantly increased lymphocyte glucocerebrosidase activity, permeated the blood-brain barrier, and decreased glucosylsphingosine levels in the cerebrospinal fluid. Myoclonus, seizures, and pupillary light reflex dysfunction markedly improved in all patients. Relief from myoclonus led to impressive recovery of gross motor function in two patients, allowing them to walk again. Pharmacological chaperone therapy with high-dose oral ambroxol shows promise in treating neuronopathic GD, necessitating further clinical trials.

  9. Generalized iterative annealing model for the action of RNA chaperones

    Science.gov (United States)

    Hyeon, Changbong; Thirumalai, D.

    2013-09-01

    As a consequence of the rugged landscape of RNA molecules their folding is described by the kinetic partitioning mechanism according to which only a small fraction (ϕF) reaches the folded state while the remaining fraction of molecules is kinetically trapped in misfolded intermediates. The transition from the misfolded states to the native state can far exceed biologically relevant time. Thus, RNA folding in vivo is often aided by protein cofactors, called RNA chaperones, that can rescue RNAs from a multitude of misfolded structures. We consider two models, based on chemical kinetics and chemical master equation, for describing assisted folding. In the passive model, applicable for class I substrates, transient interactions of misfolded structures with RNA chaperones alone are sufficient to destabilize the misfolded structures, thus entropically lowering the barrier to folding. For this mechanism to be efficient the intermediate ribonucleoprotein complex between collapsed RNA and protein cofactor should have optimal stability. We also introduce an active model (suitable for stringent substrates with small ϕF), which accounts for the recent experimental findings on the action of CYT-19 on the group I intron ribozyme, showing that RNA chaperones do not discriminate between the misfolded and the native states. In the active model, the RNA chaperone system utilizes chemical energy of adenosine triphosphate hydrolysis to repeatedly bind and release misfolded and folded RNAs, resulting in substantial increase of yield of the native state. The theory outlined here shows, in accord with experiments, that in the steady state the native state does not form with unit probability.

  10. Early embryonic gene expression profiling of zebrafish prion protein (Prp2 morphants.

    Directory of Open Access Journals (Sweden)

    Rasoul Nourizadeh-Lillabadi

    Full Text Available BACKGROUND: The Prion protein (PRNP/Prp plays a crucial role in transmissible spongiform encephalopathies (TSEs like Creutzfeldt-Jakob disease (CJD, scrapie and mad cow disease. Notwithstanding the importance in human and animal disease, fundamental aspects of PRNP/Prp function and transmission remains unaccounted for. METHODOLOGY/PRINCIPAL FINDINGS: The zebrafish (Danio rerio genome contains three Prp encoding genes assigned prp1, prp2 and prp3. Currently, the second paralogue is believed to be the most similar to the mammalian PRNP gene in structure and function. Functional studies of the PRNP gene ortholog was addressed by prp2 morpholino (MO knockdown experiments. Investigation of Prp2 depleted embryos revealed high mortality and apoptosis at 24 hours post fertilization (hpf as well as impaired brain and neuronal development. In order to elucidate the underlying mechanisms, a genome-wide transcriptome analysis was carried out in viable 24 hpf morphants. The resulting changes in gene expression profiles revealed 249 differently expressed genes linked to biological processes like cell death, neurogenesis and embryonic development. CONCLUSIONS/SIGNIFICANCE: The current study contributes to the understanding of basic Prp functions and demonstrates that the zebrafish is an excellent model to address the role of Prp in vertebrates. The gene knockdown of prp2 indicates an essential biological function for the zebrafish ortholog with a morphant phenotype that suggests a neurodegenerative action and gene expression effects which are apoptosis related and effects gene networks controlling neurogenesis and embryo development.

  11. Human prion protein (PrP) 219K is converted to PrPSc but shows heterozygous inhibition in variant Creutzfeldt-Jakob disease infection.

    Science.gov (United States)

    Hizume, Masaki; Kobayashi, Atsushi; Teruya, Kenta; Ohashi, Hiroaki; Ironside, James W; Mohri, Shirou; Kitamoto, Tetsuyuki

    2009-02-06

    Prion protein gene (PRNP) E219K is a human polymorphism commonly occurring in Asian populations but is rarely found in patients with sporadic Creutzfeldt-Jakob disease (CJD). Thus the polymorphism E219K has been considered protective against sporadic CJD. The corresponding mouse prion protein (PrP) polymorphism variant (mouse PrP 218K) is not converted to the abnormal isoform (PrP(Sc)) and shows a dominant negative effect on wild-type PrP conversion. To define the conversion activity of this human molecule, we herein established knock-in mice with human PrP 219K and performed a series of transmission experiments with human prions. Surprisingly, the human PrP 219K molecule was converted to PrP(Sc) in variant CJD infection, and the conversion occurred more efficiently than PrP 219E molecule. Notably the knock-in mice with PRNP codon 219E/K showed the least efficient conversion compared with their hemizygotes with PRNP codon 219E/0 or codon 219K/0, or homozygotes with PRNP codon 219E/E or codon 219K/K. This phenomenon indicated heterozygous inhibition. This heterozygous inhibition was observed also in knock-in mice with PRNP codon 129M/V genotype. In addition to variant CJD infection, the human PrP 219K molecule is conversion-competent in transmission experiments with sporadic CJD prions. Therefore, the protective effect of PRNP E219K against sporadic CJD might be due to heterozygous inhibition.

  12. Regulation of Nod1 by Hsp90 chaperone complex.

    Science.gov (United States)

    Hahn, Ji-Sook

    2005-08-15

    Nod1 and Nod2 proteins play important roles in mammalian innate immune responses as intracellular sensors for bacterial peptidoglycan. Nod1 and Nod2 share structural homology with many R proteins involved in plant disease resistance. It has been demonstrated that plant Hsp90 and its co-chaperone RAR1 are implicated in R-mediated disease resistance. Here the Chp-1 gene encoding a mammalian homologue of plant RAR1 was identified as a new target for transcriptional activation by heat shock factor 1 (HSF1), a stress-responsive HSF isoform. In addition, Nod1 is demonstrated to be a client protein of the Hsp90 chaperone complex containing the Chp-1. Chp-1 interacts with the tetratricopeptide repeat (TPR) domain of protein phosphatase 5 (PP5) and the ATPase domain of Hsp90 via two distinct zinc-binding cysteine and histidine rich domains (CHORDs). These findings suggest a common regulatory mechanism involving the Hsp90 chaperone complex in R-mediated disease resistance in plants and Nod1-mediated innate immune response in mammals.

  13. Familial CJD associated PrP mutants within transmembrane region induced Ctm-PrP retention in ER and triggered apoptosis by ER stress in SH-SY5Y cells.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    Full Text Available BACKGROUND: Genetic prion diseases are linked to point and inserted mutations in the prion protein (PrP gene that are presumed to favor conversion of the cellular isoform of PrP (PrP(C to the pathogenic one (PrP(Sc. The pathogenic mechanisms and the subcellular sites of the conversion are not completely understood. Here we introduce several PRNP gene mutations (such as, PrP-KDEL, PrP-3AV, PrP-A117V, PrP-G114V, PrP-P102L and PrP-E200K into the cultured cells in order to explore the pathogenic mechanism of familial prion disease. METHODOLOGY/PRINCIPAL FINDINGS: To address the roles of aberrant retention of PrP in endoplasmic reticulum (ER, the recombinant plasmids expressing full-length human PrP tailed with an ER signal peptide at the COOH-terminal (PrP-KDEL and PrP with three amino acids exchange in transmembrane region (PrP-3AV were constructed. In the preparations of transient transfections, 18-kD COOH-terminal proteolytic resistant fragments (Ctm-PrP were detected in the cells expressing PrP-KDEL and PrP-3AV. Analyses of the cell viabilities in the presences of tunicamycin and brefeldin A revealed that expressions of PrP-KDEL and PrP-3AV sensitized the transfected cells to ER stress stimuli. Western blots and RT-PCR identified the clear alternations of ER stress associated events in the cells expressing PrP-KDEL and PrP-3AV that induced ER mediated apoptosis by CHOP and caspase-12 apoptosis pathway. Moreover, several familial CJD related PrP mutants were transiently introduced into the cultured cells. Only the mutants within the transmembrane region (G114V and A117V induced the formation of Ctm-PrP and caused the ER stress, while the mutants outside the transmembrane region (P102L and E200K failed. CONCLUSIONS/SIGNIFICANCE: The data indicate that the retention of PrP in ER through formation of Ctm-PrP results in ER stress and cell apoptosis. The cytopathic activities caused by different familial CJD associated PrP mutants may vary, among them

  14. Two New PRP Conjugate Gradient Algorithms for Minimization Optimization Models.

    Science.gov (United States)

    Yuan, Gonglin; Duan, Xiabin; Liu, Wenjie; Wang, Xiaoliang; Cui, Zengru; Sheng, Zhou

    2015-01-01

    Two new PRP conjugate Algorithms are proposed in this paper based on two modified PRP conjugate gradient methods: the first algorithm is proposed for solving unconstrained optimization problems, and the second algorithm is proposed for solving nonlinear equations. The first method contains two aspects of information: function value and gradient value. The two methods both possess some good properties, as follows: 1) βk ≥ 0 2) the search direction has the trust region property without the use of any line search method 3) the search direction has sufficient descent property without the use of any line search method. Under some suitable conditions, we establish the global convergence of the two algorithms. We conduct numerical experiments to evaluate our algorithms. The numerical results indicate that the first algorithm is effective and competitive for solving unconstrained optimization problems and that the second algorithm is effective for solving large-scale nonlinear equations.

  15. Two New PRP Conjugate Gradient Algorithms for Minimization Optimization Models.

    Directory of Open Access Journals (Sweden)

    Gonglin Yuan

    Full Text Available Two new PRP conjugate Algorithms are proposed in this paper based on two modified PRP conjugate gradient methods: the first algorithm is proposed for solving unconstrained optimization problems, and the second algorithm is proposed for solving nonlinear equations. The first method contains two aspects of information: function value and gradient value. The two methods both possess some good properties, as follows: 1 βk ≥ 0 2 the search direction has the trust region property without the use of any line search method 3 the search direction has sufficient descent property without the use of any line search method. Under some suitable conditions, we establish the global convergence of the two algorithms. We conduct numerical experiments to evaluate our algorithms. The numerical results indicate that the first algorithm is effective and competitive for solving unconstrained optimization problems and that the second algorithm is effective for solving large-scale nonlinear equations.

  16. PLATELET-RICH PLASMA (PRP AND ITS APPLICATION IN THE TREATMENT OF CHRONIC AND HARD-TO-HEAL SKIN WOUNDS. A Review.

    Directory of Open Access Journals (Sweden)

    Tsvetan Sokolov

    2015-12-01

    Full Text Available In the last few years various methods are being applied in the use of platelet-rich plasma (PRP during treatment in different orthopedic disease. They allow improvement of local biological condition and regeneration of different types of tissues. PRP is a modern treatment strategy with worldwide recognition. There is a high concentration of platelet growth factors in small amounts of plasma. PRP and its various forms have become one of the best methods to support the healing process of various tissues. PRP is used in regenerative medicine, because it provides two of three components (growth factors and scaffolds necessary for complete tissue regeneration. The particular reason for the appearance of lesions is important in order to select an appropriate treatment method and technical application. PRP may be used for treatment of various chronic and hard-to-heal cutaneous wounds, especially when standard conventional therapy is not good enough and surgical treatment is not possible. It reduces the duration, cost of treatment and the hospital stay. There is reduction of wound pain after starting the treatment, reduced risk of blood-borne disease transmission, wound healing is restored, and local immunity is activated.

  17. Ubiquitin ligase gp78 targets unglycosylated prion protein PrP for ubiquitylation and degradation.

    Directory of Open Access Journals (Sweden)

    Jia Shao

    Full Text Available Prion protein PrP is a central player in several devastating neurodegenerative disorders, including mad cow disease and Creutzfeltd-Jacob disease. Conformational alteration of PrP into an aggregation-prone infectious form PrPSc can trigger pathogenic events. How levels of PrP are regulated is poorly understood. Human PrP is known to be degraded by the proteasome, but the specific proteolytic pathway responsible for PrP destruction remains elusive. Here, we demonstrate that the ubiquitin ligase gp78, known for its role in protein quality control, is critical for unglycosylated PrP ubiquitylation and degradation. Furthermore, C-terminal sequences of PrP protein are crucial for its ubiquitylation and degradation. Our study reveals the first ubiquitin ligase specifically involved in prion protein PrP degradation and PrP sequences crucial for its turnover. Our data may lead to a new avenue to control PrP level and pathogenesis.

  18. Bacillus subtilis PrsA is required in vivo as an extracytoplasmic chaperone for secretion of active enzymes synthesized either with or without pro-sequences

    DEFF Research Database (Denmark)

    Jacobs, M; Kontinen, V; Sarvas, M

    1993-01-01

    In prsA (protein secretion) mutants of Bacillus subtilis, decreased levels of exoproteins, including alpha-amylase and subtilisins, are found extracellularly. The effect of prsA on subtilisin secretion is elaborated here. Extracytoplasmic folding and secretion of active subtilisin is assisted...

  19. The pharmacological chaperone AT2220 increases the specific activity and lysosomal delivery of mutant acid alpha-glucosidase, and promotes glycogen reduction in a transgenic mouse model of Pompe disease.

    Directory of Open Access Journals (Sweden)

    Richie Khanna

    Full Text Available Pompe disease is an inherited lysosomal storage disorder that results from a deficiency in acid α-glucosidase (GAA activity due to mutations in the GAA gene. Pompe disease is characterized by accumulation of lysosomal glycogen primarily in heart and skeletal muscles, which leads to progressive muscle weakness. We have shown previously that the small molecule pharmacological chaperone AT2220 (1-deoxynojirimycin hydrochloride, duvoglustat hydrochloride binds and stabilizes wild-type as well as multiple mutant forms of GAA, and can lead to higher cellular levels of GAA. In this study, we examined the effect of AT2220 on mutant GAA, in vitro and in vivo, with a primary focus on the endoplasmic reticulum (ER-retained P545L mutant form of human GAA (P545L GAA. AT2220 increased the specific activity of P545L GAA toward both natural (glycogen and artificial substrates in vitro. Incubation with AT2220 also increased the ER export, lysosomal delivery, proteolytic processing, and stability of P545L GAA. In a new transgenic mouse model of Pompe disease that expresses human P545L on a Gaa knockout background (Tg/KO and is characterized by reduced GAA activity and elevated glycogen levels in disease-relevant tissues, daily oral administration of AT2220 for 4 weeks resulted in significant and dose-dependent increases in mature lysosomal GAA isoforms and GAA activity in heart and skeletal muscles. Importantly, oral administration of AT2220 also resulted in significant glycogen reduction in disease-relevant tissues. Compared to daily administration, less-frequent AT2220 administration, including repeated cycles of 4 or 5 days with AT2220 followed by 3 or 2 days without drug, respectively, resulted in even greater glycogen reductions. Collectively, these data indicate that AT2220 increases the specific activity, trafficking, and lysosomal stability of P545L GAA, leads to increased levels of mature GAA in lysosomes, and promotes glycogen reduction in situ. As

  20. The Pharmacological Chaperone AT2220 Increases the Specific Activity and Lysosomal Delivery of Mutant Acid Alpha-Glucosidase, and Promotes Glycogen Reduction in a Transgenic Mouse Model of Pompe Disease

    Science.gov (United States)

    Lun, Yi; Soska, Rebecca; Feng, Jessie; Dhulipala, Rohini; Frascella, Michelle; Garcia, Anadina; Pellegrino, Lee J.; Xu, Su; Brignol, Nastry; Toth, Matthew J.; Do, Hung V.; Lockhart, David J.; Wustman, Brandon A.; Valenzano, Kenneth J.

    2014-01-01

    Pompe disease is an inherited lysosomal storage disorder that results from a deficiency in acid α-glucosidase (GAA) activity due to mutations in the GAA gene. Pompe disease is characterized by accumulation of lysosomal glycogen primarily in heart and skeletal muscles, which leads to progressive muscle weakness. We have shown previously that the small molecule pharmacological chaperone AT2220 (1-deoxynojirimycin hydrochloride, duvoglustat hydrochloride) binds and stabilizes wild-type as well as multiple mutant forms of GAA, and can lead to higher cellular levels of GAA. In this study, we examined the effect of AT2220 on mutant GAA, in vitro and in vivo, with a primary focus on the endoplasmic reticulum (ER)-retained P545L mutant form of human GAA (P545L GAA). AT2220 increased the specific activity of P545L GAA toward both natural (glycogen) and artificial substrates in vitro. Incubation with AT2220 also increased the ER export, lysosomal delivery, proteolytic processing, and stability of P545L GAA. In a new transgenic mouse model of Pompe disease that expresses human P545L on a Gaa knockout background (Tg/KO) and is characterized by reduced GAA activity and elevated glycogen levels in disease-relevant tissues, daily oral administration of AT2220 for 4 weeks resulted in significant and dose-dependent increases in mature lysosomal GAA isoforms and GAA activity in heart and skeletal muscles. Importantly, oral administration of AT2220 also resulted in significant glycogen reduction in disease-relevant tissues. Compared to daily administration, less-frequent AT2220 administration, including repeated cycles of 4 or 5 days with AT2220 followed by 3 or 2 days without drug, respectively, resulted in even greater glycogen reductions. Collectively, these data indicate that AT2220 increases the specific activity, trafficking, and lysosomal stability of P545L GAA, leads to increased levels of mature GAA in lysosomes, and promotes glycogen reduction in situ. As such, AT2220 may

  1. Molecular chaperones: The modular evolution of cellular networks

    Indian Academy of Sciences (India)

    2007-03-22

    Mar 22, 2007 ... Molecular chaperones play a prominent role in signaling and transcriptional regulatory networks of the cell. Recent advances uncovered that chaperones act as genetic buffers stabilizing the phenotype of various cells and organisms and may serve as potential regulators of evolvability. Chaperones have ...

  2. Effective Chaperone Selection and Training for Enhanced Youth Experiences

    Science.gov (United States)

    Anderson, Emily J.; Roop, Kelsey; MacArthur, Stacey

    2017-01-01

    This article identifies key strategies for selecting and training chaperones for youth programs. Although substantial research on volunteer core competencies and training exists, very little has been written to specifically address volunteers who serve in a chaperone capacity. We surveyed chaperones who had participated in an international youth…

  3. Pathogenic Mutations Differentially Affect the Catalytic Activities of the Human B12-processing Chaperone CblC and Increase Futile Redox Cycling*

    Science.gov (United States)

    Gherasim, Carmen; Ruetz, Markus; Li, Zhu; Hudolin, Stephanie; Banerjee, Ruma

    2015-01-01

    Human CblC catalyzes the elimination of the upper axial ligand in cobalamin or B12 derivatives entering the cell from circulation. This processing step is critical for assimilation of dietary cobalamin into the active cofactor forms that support the B12-dependent enzymes, methionine synthase and methylmalonyl-CoA mutase. Using a modified nitroreductase scaffold tailored to bind cobalamin and glutathione, CblC exhibits versatility in the mechanism by which it removes cyano versus alkyl ligands in cobalamin. In this study, we have characterized the effects of two pathogenic missense mutations at the same residue, R161G and R161Q, which are associated with early and late onset of the CblC disorder, respectively. We find that the R161Q and R161G CblC mutants display lower protein stability and decreased dealkylation but not decyanation activity, suggesting that cyanocobalamin might be therapeutically useful for patients carrying mutations at Arg-161. The mutant proteins also exhibit impaired glutathione binding. In the presence of physiologically relevant glutathione concentrations, stabilization of the cob(II)alamin derivative is observed, which occurs at the expense of increased oxidation of glutathione. Futile redox cycling, which is suppressed in wild-type human CblC, explains the reported increase in oxidative stress levels associated with the CblC disorder. PMID:25809485

  4. Pathogenic mutations differentially affect the catalytic activities of the human B12-processing chaperone CblC and increase futile redox cycling.

    Science.gov (United States)

    Gherasim, Carmen; Ruetz, Markus; Li, Zhu; Hudolin, Stephanie; Banerjee, Ruma

    2015-05-01

    Human CblC catalyzes the elimination of the upper axial ligand in cobalamin or B12 derivatives entering the cell from circulation. This processing step is critical for assimilation of dietary cobalamin into the active cofactor forms that support the B12-dependent enzymes, methionine synthase and methylmalonyl-CoA mutase. Using a modified nitroreductase scaffold tailored to bind cobalamin and glutathione, CblC exhibits versatility in the mechanism by which it removes cyano versus alkyl ligands in cobalamin. In this study, we have characterized the effects of two pathogenic missense mutations at the same residue, R161G and R161Q, which are associated with early and late onset of the CblC disorder, respectively. We find that the R161Q and R161G CblC mutants display lower protein stability and decreased dealkylation but not decyanation activity, suggesting that cyanocobalamin might be therapeutically useful for patients carrying mutations at Arg-161. The mutant proteins also exhibit impaired glutathione binding. In the presence of physiologically relevant glutathione concentrations, stabilization of the cob(II)alamin derivative is observed, which occurs at the expense of increased oxidation of glutathione. Futile redox cycling, which is suppressed in wild-type human CblC, explains the reported increase in oxidative stress levels associated with the CblC disorder. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Prp19 Arrests Cell Cycle via Cdc5L in Hepatocellular Carcinoma Cells.

    Science.gov (United States)

    Huang, Renzheng; Xue, Ruyi; Qu, Di; Yin, Jie; Shen, Xi-Zhong

    2017-04-07

    Pre-mRNA processing factor 19 (Prp19) is involved in many cellular events including pre-mRNA processing and DNA damage response. Recently, it has been identified as a candidate oncogene in hepatocellular carcinoma (HCC). However, the role of Prp19 in tumor biology is still elusive. Here, we reported that Prp19 arrested cell cycle in HCC cells via regulating G2/M transition. Mechanistic insights revealed that silencing Prp19 inhibited the expression of cell division cycle 5-like (Cdc5L) via repressing the translation of Cdc5L mRNA and facilitating lysosome-mediated degradation of Cdc5L in HCC cells. Furthermore, we found that silencing Prp19 induced cell cycle arrest could be partially resumed by overexpressing Cdc5L. This work implied that Prp19 participated in mitotic progression and thus could be a promising therapeutic target of HCC.

  6. Investigating the Chaperone Properties of a Novel Heat Shock Protein, Hsp70.c, from Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Adélle Burger

    2014-01-01

    Full Text Available The neglected tropical disease, African Trypanosomiasis, is fatal and has a crippling impact on economic development. Heat shock protein 70 (Hsp70 is an important molecular chaperone that is expressed in response to stress and Hsp40 acts as its co-chaperone. These proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. A novel cytosolic Hsp70, from Trypanosoma brucei, TbHsp70.c, contains an acidic substrate binding domain and lacks the C-terminal EEVD motif. The ability of a cytosolic Hsp40 from Trypanosoma brucei J protein 2, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated. The main objective was to functionally characterize TbHsp70.c to further expand our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed the ability to suppress aggregation of thermolabile MDH and chemically denatured rhodanese. ATPase assays revealed a 2.8-fold stimulation of the ATPase activity of TbHsp70.c by Tbj2. TbHsp70.c and Tbj2 both demonstrated chaperone activity and Tbj2 functions as a co-chaperone of TbHsp70.c. In vivo heat stress experiments indicated upregulation of the expression levels of TbHsp70.c.

  7. Functional adaptations of the bacterial chaperone trigger factor to extreme environmental temperatures.

    Science.gov (United States)

    Godin-Roulling, Amandine; Schmidpeter, Philipp A M; Schmid, Franz X; Feller, Georges

    2015-07-01

    Trigger factor (TF) is the first molecular chaperone interacting cotranslationally with virtually all nascent polypeptides synthesized by the ribosome in bacteria. Thermal adaptation of chaperone function was investigated in TFs from the Antarctic psychrophile Pseudoalteromonas haloplanktis, the mesophile Escherichia coli and the hyperthermophile Thermotoga maritima. This series covers nearly all temperatures encountered by bacteria. Although structurally homologous, these TFs display strikingly distinct properties that are related to the bacterial environmental temperature. The hyperthermophilic TF strongly binds model proteins during their folding and protects them from heat-induced misfolding and aggregation. It decreases the folding rate and counteracts the fast folding rate imposed by high temperature. It also functions as a carrier of partially folded proteins for delivery to downstream chaperones ensuring final maturation. By contrast, the psychrophilic TF displays weak chaperone activities, showing that these functions are less important in cold conditions because protein folding, misfolding and aggregation are slowed down at low temperature. It efficiently catalyses prolyl isomerization at low temperature as a result of its increased cellular concentration rather than from an improved activity. Some chaperone properties of the mesophilic TF possibly reflect its function as a cold shock protein in E. coli. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Prp22 and spliceosome components regulate chromatin dynamics in germ-line polyploid cells.

    Directory of Open Access Journals (Sweden)

    Stephen Klusza

    Full Text Available During Drosophila oogenesis, the endopolyploid nuclei of germ-line nurse cells undergo a dramatic shift in morphology as oogenesis progresses; the easily-visible chromosomes are initially polytenic during the early stages of oogenesis before they transiently condense into a distinct '5-blob' configuration, with subsequent dispersal into a diffuse state. Mutations in many genes, with diverse cellular functions, can affect the ability of nurse cells to fully decondense their chromatin, resulting in a '5-blob arrest' phenotype that is maintained throughout the later stages of oogenesis. However, the mechanisms and significance of nurse-cell (NC chromatin dispersal remain poorly understood. Here, we report that a screen for modifiers of the 5-blob phenotype in the germ line isolated the spliceosomal gene peanuts, the Drosophila Prp22. We demonstrate that reduction of spliceosomal activity through loss of peanuts promotes decondensation defects in NC nuclei during mid-oogenesis. We also show that the Prp38 spliceosomal protein accumulates in the nucleoplasm of nurse cells with impaired peanuts function, suggesting that spliceosomal recycling is impaired. Finally, we reveal that loss of additional spliceosomal proteins impairs the full decondensation of NC chromatin during later stages of oogenesis, suggesting that individual spliceosomal subcomplexes modulate expression of the distinct subset of genes that are required for correct morphology in endopolyploid nurse cells.

  9. Prp22 and Spliceosome Components Regulate Chromatin Dynamics in Germ-Line Polyploid Cells

    Science.gov (United States)

    Klusza, Stephen; Novak, Amanda; Figueroa, Shirelle; Palmer, William; Deng, Wu-Min

    2013-01-01

    During Drosophila oogenesis, the endopolyploid nuclei of germ-line nurse cells undergo a dramatic shift in morphology as oogenesis progresses; the easily-visible chromosomes are initially polytenic during the early stages of oogenesis before they transiently condense into a distinct ‘5-blob’ configuration, with subsequent dispersal into a diffuse state. Mutations in many genes, with diverse cellular functions, can affect the ability of nurse cells to fully decondense their chromatin, resulting in a ‘5-blob arrest’ phenotype that is maintained throughout the later stages of oogenesis. However, the mechanisms and significance of nurse-cell (NC) chromatin dispersal remain poorly understood. Here, we report that a screen for modifiers of the 5-blob phenotype in the germ line isolated the spliceosomal gene peanuts, the Drosophila Prp22. We demonstrate that reduction of spliceosomal activity through loss of peanuts promotes decondensation defects in NC nuclei during mid-oogenesis. We also show that the Prp38 spliceosomal protein accumulates in the nucleoplasm of nurse cells with impaired peanuts function, suggesting that spliceosomal recycling is impaired. Finally, we reveal that loss of additional spliceosomal proteins impairs the full decondensation of NC chromatin during later stages of oogenesis, suggesting that individual spliceosomal subcomplexes modulate expression of the distinct subset of genes that are required for correct morphology in endopolyploid nurse cells. PMID:24244416

  10. Intraarticular Injections of Platelet-rich Plasma (PRP) in the Management of Knee Osteoarthritis

    OpenAIRE

    E. Carlos RODRIGUEZ-MERCHAN

    2013-01-01

      The clinical use of PRP therapy in the practical setting of orthopaedic fields is increasing partly because of the accessibility of devices that are used in outpatient preparation and delivery. Another reason is the strong advertisement of PRP procedures as the ultimate treatment and novel technology for knee problems by a few orthopaedic surgeons based on claims of abundant scientific evidence. Hence, PubMed articles related to the clinical use of PRP in knee osteoarthritis were searched u...

  11. The Splicing Factor Prp43p, a DEAH Box ATPase, Functions in Ribosome Biogenesis

    Science.gov (United States)

    Leeds, Nina B.; Small, Eliza C.; Hiley, Shawna L.; Hughes, Timothy R.; Staley, Jonathan P.

    2006-01-01

    Biogenesis of the small and large ribosomal subunits requires modification, processing, and folding of pre-rRNA to yield mature rRNA. Here, we report that efficient biogenesis of both small- and large-subunit rRNAs requires the DEAH box ATPase Prp43p, a pre-mRNA splicing factor. By steady-state analysis, a cold-sensitive prp43 mutant accumulates 35S pre-rRNA and depletes 20S, 27S, and 7S pre-rRNAs, precursors to the small- and large-subunit rRNAs. By pulse-chase analysis, the prp43 mutant is defective in the formation of 20S and 27S pre-rRNAs and in the accumulation of 18S and 25S mature rRNAs. Wild-type Prp43p immunoprecipitates pre-rRNAs and mature rRNAs, indicating a direct role in ribosome biogenesis. The Prp43p-Q423N mutant immunoprecipitates 27SA2 pre-rRNA threefold more efficiently than the wild type, suggesting a critical role for Prp43p at the earliest stages of large-subunit biogenesis. Consistent with an early role for Prp43p in ribosome biogenesis, Prp43p immunoprecipitates the majority of snoRNAs; further, compared to the wild type, the prp43 mutant generally immunoprecipitates the snoRNAs more efficiently. In the prp43 mutant, the snoRNA snR64 fails to methylate residue C2337 in 27S pre-rRNA, suggesting a role in snoRNA function. We propose that Prp43p promotes recycling of snoRNAs and biogenesis factors during pre-rRNA processing, similar to its recycling role in pre-mRNA splicing. The dual function for Prp43p in the cell raises the possibility that ribosome biogenesis and pre-mRNA splicing may be coordinately regulated. PMID:16382143

  12. HGF mediates the anti-inflammatory effects of PRP on injured tendons.

    Directory of Open Access Journals (Sweden)

    Jianying Zhang

    Full Text Available Platelet-rich plasma (PRP containing hepatocyte growth factor (HGF and other growth factors are widely used in orthopaedic/sports medicine to repair injured tendons. While PRP treatment is reported to decrease pain in patients with tendon injury, the mechanism of this effect is not clear. Tendon pain is often associated with tendon inflammation, and HGF is known to protect tissues from inflammatory damages. Therefore, we hypothesized that HGF in PRP causes the anti-inflammatory effects. To test this hypothesis, we performed in vitro experiments on rabbit tendon cells and in vivo experiments on a mouse Achilles tendon injury model. We found that addition of PRP or HGF decreased gene expression of COX-1, COX-2, and mPGES-1, induced by the treatment of tendon cells in vitro with IL-1β. Further, the treatment of tendon cell cultures with HGF antibodies reduced the suppressive effects of PRP or HGF on IL-1β-induced COX-1, COX-2, and mPGES-1 gene expressions. Treatment with PRP or HGF almost completely blocked the cellular production of PGE2 and the expression of COX proteins. Finally, injection of PRP or HGF into wounded mouse Achilles tendons in vivo decreased PGE2 production in the tendinous tissues. Injection of platelet-poor plasma (PPP however, did not reduce PGE2 levels in the wounded tendons, but the injection of HGF antibody inhibited the effects of PRP and HGF. Further, injection of PRP or HGF also decreased COX-1 and COX-2 proteins. These results indicate that PRP exerts anti-inflammatory effects on injured tendons through HGF. This study provides basic scientific evidence to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2.

  13. Heat shock protein 90: the cancer chaperone

    Indian Academy of Sciences (India)

    Madhu Sudhan

    2007-04-02

    Apr 2, 2007 ... Auluck P K, Chan H Y, Trojanowski J Q, Lee V M -Y and Bonini. N M 2002a Chaperone suppression of alpha-synuclein toxicity in a Drosophila model for Parkinson's disease; Science 295. 865–868. Bagatell R and Whitesell L 2004 Altered Hsp90 function in cancer: a unique therapeutic opportunity; Mol.

  14. Chaperone binding at the ribosomal exit tunnel

    DEFF Research Database (Denmark)

    Kristensen, Ole; Gajhede, Michael

    2003-01-01

    The exit tunnel region of the ribosome is well established as a focal point for interaction between the components that guide the fate of nascent polypeptides. One of these, the chaperone trigger factor (TF), associates with the 50S ribosomal subunit through its N-terminal domain. Targeting of TF...

  15. Reconfiguration of the proteasome during chaperone-mediated assembly

    OpenAIRE

    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 ? ring of the proteasome core particle (CP) in the mature proteasome, with the Rpt C-terminal tails inserting into pockets of the ? ring 1?4 . Rpt ring assembly is mediated by four chaperones, each binding a distinct Rpt subunit 5?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 th...

  16. Quantitative analysis of the interplay between hsc70 and its co-chaperone HspBP1

    Directory of Open Access Journals (Sweden)

    Hicham Mahboubi

    2015-12-01

    Full Text Available Background. Chaperones and their co-factors are components of a cellular network; they collaborate to maintain proteostasis under normal and harmful conditions. In particular, hsp70 family members and their co-chaperones are essential to repair damaged proteins. Co-chaperones are present in different subcellular compartments, where they modulate chaperone activities.Methods and Results. Our studies assessed the relationship between hsc70 and its co-factor HspBP1 in human cancer cells. HspBP1 promotes nucleotide exchange on hsc70, but has also chaperone-independent functions. We characterized the interplay between hsc70 and HspBP1 by quantitative confocal microscopy combined with automated image analyses and statistical evaluation. Stress and the recovery from insult changed significantly the subcellular distribution of hsc70, but had little effect on HspBP1. Single-cell measurements and regression analysis revealed that the links between the chaperone and its co-factor relied on (i the physiological state of the cell and (ii the subcellular compartment. As such, we identified a linear relationship and strong correlation between hsc70 and HspBP1 distribution in control and heat-shocked cells; this correlation changed in a compartment-specific fashion during the recovery from stress. Furthermore, we uncovered significant stress-induced changes in the colocalization between hsc70 and HspBP1 in the nucleus and cytoplasm.Discussion. Our quantitative approach defined novel properties of the co-chaperone HspBP1 as they relate to its interplay with hsc70. We propose that changes in cell physiology promote chaperone redistribution and thereby stimulate chaperone-independent functions of HspBP1.

  17. The Malarial Exported PFA0660w Is an Hsp40 Co-Chaperone of PfHsp70-x.

    Directory of Open Access Journals (Sweden)

    Michael O Daniyan

    Full Text Available Plasmodium falciparum, the human pathogen responsible for the most dangerous malaria infection, survives and develops in mature erythrocytes through the export of proteins needed for remodelling of the host cell. Molecular chaperones of the heat shock protein (Hsp family are prominent members of the exportome, including a number of Hsp40s and a Hsp70. PFA0660w, a type II Hsp40, has been shown to be exported and possibly form a complex with PfHsp70-x in the infected erythrocyte cytosol. However, the chaperone properties of PFA0660w and its interaction with human and parasite Hsp70s are yet to be investigated. Recombinant PFA0660w was found to exist as a monomer in solution, and was able to significantly stimulate the ATPase activity of PfHsp70-x but not that of a second plasmodial Hsp70 (PfHsp70-1 or a human Hsp70 (HSPA1A, indicating a potential specific functional partnership with PfHsp70-x. Protein binding studies in the presence and absence of ATP suggested that the interaction of PFA0660w with PfHsp70-x most likely represented a co-chaperone/chaperone interaction. Also, PFA0660w alone produced a concentration-dependent suppression of rhodanese aggregation, demonstrating its chaperone properties. Overall, we have provided the first biochemical evidence for the possible role of PFA0660w as a chaperone and as co-chaperone of PfHsp70-x. We propose that these chaperones boost the chaperone power of the infected erythrocyte, enabling successful protein trafficking and folding, and thereby making a fundamental contribution to the pathology of malaria.

  18. Kinetics and thermodynamics of the thermal inactivation and chaperone assisted folding of zebrafish dihydrofolate reductase.

    Science.gov (United States)

    Thapliyal, Charu; Jain, Neha; Rashid, Naira; Chaudhuri Chattopadhyay, Pratima

    2017-11-11

    The maintenance of thermal stability is a major issue in protein engineering as many proteins tend to form inactive aggregates at higher temperatures. Zebrafish DHFR, an essential protein for the survival of cells, shows irreversible thermal unfolding transition. The protein exhibits complete unfolding and loss of activity at 50 °C as monitored by UV-Visible, fluorescence and far UV-CD spectroscopy. The heat induced inactivation of zDHFR follows first-order kinetics and Arrhenius law. The variation in the value of inactivation rate constant, k with increasing temperatures depicts faster inactivation at elevated temperatures. We have attempted to study the chaperoning ability of a shorter variant of GroEL (minichaperone) and compared it with that of conventional GroEL-GroES chaperone system. Both the chaperone system prevented the aggregation and assisted in refolding of zDHFR. The rate of thermal inactivation was significantly retarded in the presence of chaperones which indicate that it enhances the thermal stability of the enzyme. As minichaperone is less complex, and does not require high energy co-factors like ATP, for its function as compared to conventional GroEL-GroES system, it can act as a very good in vitro as well as in vivo chaperone model for monitoring assisted protein folding phenomenon. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Yeast prions are useful for studying protein chaperones and protein quality control.

    Science.gov (United States)

    Masison, Daniel C; Reidy, Michael

    2015-01-01

    Protein chaperones help proteins adopt and maintain native conformations and play vital roles in cellular processes where proteins are partially folded. They comprise a major part of the cellular protein quality control system that protects the integrity of the proteome. Many disorders are caused when proteins misfold despite this protection. Yeast prions are fibrous amyloid aggregates of misfolded proteins. The normal action of chaperones on yeast prions breaks the fibers into pieces, which results in prion replication. Because this process is necessary for propagation of yeast prions, even small differences in activity of many chaperones noticeably affect prion phenotypes. Several other factors involved in protein processing also influence formation, propagation or elimination of prions in yeast. Thus, in much the same way that the dependency of viruses on cellular functions has allowed us to learn much about cell biology, the dependency of yeast prions on chaperones presents a unique and sensitive way to monitor the functions and interactions of many components of the cell's protein quality control system. Our recent work illustrates the utility of this system for identifying and defining chaperone machinery interactions.

  20. Reconstrucción mamaria mediante lipoinfiltrado enriquecido con PRP

    Directory of Open Access Journals (Sweden)

    A. Jarrah

    2013-12-01

    Full Text Available Presentamos una serie de pacientes con mastectomía a las que hemos realizado reconstrucción mamaria con infiltraciones de grasa (lipoinfiltrado enriquecida con plasma rico en plaquetas (PRP como único procedimiento, o como paso previo a la colocación de un implante mamario. El objetivo de este trabajo es presentar una alternativa a la reconstrucción mamaria con colgajos libres o pediculados en mamas sometidas a radioterapia; también, una revisión detallada de los pasos a seguir para la realización de este procedimiento, que van desde la extracción de sangre para la posterior obtención del PRP, hasta la técnica de infiltración de grasa enriquecida con dichos factores en la mama intervenida. Con esta técnica de enriquecimiento de la grasa hemos logrado mejores resultados y mayor permanencia de los injertos grasos. Evaluando los postoperatorios de las pacientes sometidas a este procedimiento, hemos observado que se necesitan de 2 a 3 tiempos de lipoinfiltrado para obtener buena cobertura y mejoría de la calidad de piel como paso previo a la colocación del implante en este tipo de pacientes.

  1. Cytosolic iron chaperones: Proteins delivering iron cofactors in the cytosol of mammalian cells.

    Science.gov (United States)

    Philpott, Caroline C; Ryu, Moon-Suhn; Frey, Avery; Patel, Sarju

    2017-08-04

    Eukaryotic cells contain hundreds of metalloproteins that are supported by intracellular systems coordinating the uptake and distribution of metal cofactors. Iron cofactors include heme, iron-sulfur clusters, and simple iron ions. Poly(rC)-binding proteins are multifunctional adaptors that serve as iron ion chaperones in the cytosolic/nuclear compartment, binding iron at import and delivering it to enzymes, for storage (ferritin) and export (ferroportin). Ferritin iron is mobilized by autophagy through the cargo receptor, nuclear co-activator 4. The monothiol glutaredoxin Glrx3 and BolA2 function as a [2Fe-2S] chaperone complex. These proteins form a core system of cytosolic iron cofactor chaperones in mammalian cells. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Both Hsp70 chaperone and Clp protease plastidial systems are required for protection against oxidative stress.

    Science.gov (United States)

    Pulido, Pablo; Llamas, Ernesto; Rodriguez-Concepcion, Manuel

    2017-03-04

    Environmental stress conditions such as high light, extreme temperatures, salinity or drought trigger oxidative stress and eventually protein misfolding in plants. In chloroplasts, chaperone systems refold proteins after stress, while proteases degrade misfolded and aggregated proteins that cannot be refolded. We observed that reduced activity of chloroplast Hsp70 chaperone or Clp protease systems both prevented growth of Arabidopsis thaliana seedlings after treatment with the oxidative agent methyl viologen. Besides showing a role for these particular protein quality control components on the protection against oxidative stress, we provide evidence supporting the existence of a yet undiscovered pathway for Clp-mediated degradation of the damaged proteins.

  3. Prp43p Is a DEAH-Box Spliceosome Disassembly Factor Essential for Ribosome Biogenesis

    Science.gov (United States)

    Combs, D. Joshua; Nagel, Roland J.; Ares, Manuel; Stevens, Scott W.

    2006-01-01

    The known function of the DEXH/D-box protein Prp43p is the removal of the U2, U5, and U6 snRNPs from the postsplicing lariat-intron ribonucleoprotein complex. We demonstrate that affinity-purified Prp43p-associated material includes the expected spliceosomal components; however, we also identify several preribosomal complexes that are specifically purified with Prp43p. Conditional prp43 mutant alleles confer a 35S pre-rRNA processing defect, with subsequent depletion of 27S and 20S precursors. Upon a shift to a nonpermissive temperature, both large and small-ribosomal-subunit proteins accumulate in the nucleolus of prp43 mutants. Pulse-chase analysis demonstrates delayed kinetics of 35S, 27S, and 20S pre-rRNA processing with turnover of these intermediates. Microarray analysis of pre-mRNA splicing defects in prp43 mutants shows a very mild effect, similar to that of nonessential pre-mRNA splicing factors. Prp43p is the first DEXH/D-box protein shown to function in both RNA polymerase I and polymerase II transcript metabolism. Its essential function is in its newly characterized role in ribosome biogenesis of both ribosomal subunits, positioning Prp43p to regulate both pre-mRNA splicing and ribosome biogenesis. PMID:16382144

  4. Recommendations for the Involvement of Patient Research Partners (PRP) in OMERACT Working Groups. A Report from the OMERACT 2014 Working Group on PRP.

    Science.gov (United States)

    Cheung, Peter P; de Wit, Maarten; Bingham, Clifton O; Kirwan, John R; Leong, Amye; March, Lyn M; Montie, Pam; Scholte-Voshaar, Marieke; Gossec, Laure

    2016-01-01

    Patient participation in research is increasing; however, practical guidelines to enhance this participation are lacking. Specifically within the Outcome Measures in Rheumatology (OMERACT) organization, although patients have participated in OMERACT meetings since 2002, consensus about the procedures for involving patients in working groups has not been formalized. The objective is to develop a set of recommendations regarding patient research partner (PRP) involvement in research working groups. We conducted a systematic literature review on recommendations/guidelines of PRP involvement in research; elaborated a structured consensus process involving multiple participants to develop a set of recommendations; and sought endorsement of recommendations by OMERACT. In the 18 articles included in the literature review, there was general agreement on the broad concepts for recommendations covering PRP involvement in research although they were heterogeneous in detail. Most considered PRP involvement in all phases of research with early engagement, training, and support important, but details on the content were scarce. This review informed a larger consensus-building process regarding PRP inclusion in OMERACT research. Three overarching principles and 8 recommendations were developed, discussed, and refined at OMERACT 2014. The guiding principles were endorsed during the OMERACT plenary session. These recommendations for PRP involvement in OMERACT research reinforce the importance of patient participation throughout the research process as integral members. Although the applicability of the recommendations in other research contexts should be assessed, the generalizability is expected to be high. Future research should evaluate their implementation and their effect on outcome development.

  5. Chaperone proteostasis in Parkinson's disease : stabilization of the Hsp70/alpha-synuclein complex by Hip

    NARCIS (Netherlands)

    Roodveldt, Cintia; Bertoncini, Carlos W.; Andersson, August; van der Goot, Annemieke T.; Hsu, Shang-Te; Fernandez-Montesinos, Rafael; de Jong, Jannie; van Ham, Tjakko J.; Nollen, Ellen A.; Pozo, David; Christodoulou, John; Dobson, Christopher M.

    2009-01-01

    The ATP-dependent protein chaperone heat-shock protein 70 (Hsp70) displays broad anti-aggregation functions and has a critical function in preventing protein misfolding pathologies. According to in vitro and in vivo models of Parkinson's disease (PD), loss of Hsp70 activity is associated with

  6. The composite of bone marrow concentrate and PRP as an alternative to autologous bone grafting.

    Directory of Open Access Journals (Sweden)

    Mohssen Hakimi

    Full Text Available One possible alternative to the application of autologous bone grafts represents the use of autologous bone marrow concentrate (BMC. The purpose of our study was to evaluate the potency of autologous platelet-rich plasma (PRP in combination with BMC. In 32 mini-pigs a metaphyseal critical-size defect was surgically created at the proximal tibia. The animals were allocated to four treatment groups of eight animals each (1. BMC+CPG group, 2. BMC+CPG+PRP group, 3. autograft group, 4. CPG group. In the BMC+CPG group the defect was filled with autologous BMC in combination with calcium phosphate granules (CPG, whereas in the BMC+CPG+PRP group the defect was filled with the composite of autologous BMC, CPG and autologous PRP. In the autograft group the defect was filled with autologous cancellous graft, whereas in the CPG group the defect was filled with CPG solely. After 6 weeks radiological and histomorphometrical analysis showed significantly more new bone formation in the BMC+CPG+PRP group compared to the BMC+CPG group and the CPG group. There were no significant differences between the BMC+CPG+PRP group and the autograft group. In the PRP platelets were enriched significantly about 4.7-fold compared to native blood. In BMC the count of mononuclear cells increased significantly (3.5-fold compared to the bone marrow aspirate. This study demonstrates that the composite of BMC+CPG+PRP leads to a significantly higher bone regeneration of critical-size defects at the proximal tibia in mini-pigs than the use of BMC+CPG without PRP. Furthermore, within the limits of the present study the composite BMC+CPG+PRP represents a comparable alternative to autologous bone grafting.

  7. Comparative Analysis of the Index of Success of Implantations with Osteointegrations with and without the Use of PRP, in the Protocol of Setting Análise Comparativa do Índice de Sucesso dos Implantes Osteointegrados com e sem a Utilização de PRP, no Protocolo de Fixação

    Directory of Open Access Journals (Sweden)

    Adriana Passanezi

    2004-10-01

    Full Text Available This work deals with the data gathering of 1267 dental records from CID – Center of Dental Implants in Londrina, evaluating the success and loss results of osteo-integrated implants and separating them by trademark of the implant FOB – USP and ACTIVE (this one with two types of surface: smooth and sandblasted and whether the PRP was used or not in the protocol of setting. One thousand five hundred and seventy-two implants were analyzed. In 642 of them the PRP was used in the protocol of setting and there were 16 losses which represent a success percentage of 97,51%. In 930 implants the PRP was not used and there were 66 losses, showing a success index of 92,90%. The results were discussed based on the current literature, and it was concluded that the PRP used in the protocol of implant setting leads to a loss reduction of the osteo-integrated implants, increasing the success index; the influence of the PRP in the success index of osteo-integrated implants is more significant in the maxilla than in the mandible; the PRP represents a promising material in the processes of bone reconstruction in a general sense, being its use recommended in certain situations of implant settings.   O presente trabalho refere-se ao levantamento de dados de 1267 prontuários do CID – Centro de Implantes Dentários de Londrina. Os resultados de sucessos e perdas de implantes ósseo-integrados foram anotados e, a seguir, separados por marca do implante FOB-USP e ACTIVE, este com dois tipos de superfície (lisa ou jateada. Também se verificou se houve ou não utilização de PRP no protocolo de fixação.Foi analisado o total de 1572 implantes, em 642 dos quais foi utilizado o PRP no protocolo de fixação. Ocorreram 16 perdas,representando um percentual de sucesso de 97,51%. Em 930 implantes, não foi utilizado o PRP e houve 66 perdas, demonstrando um índice de sucesso de 92,90%. Os resultados foram discutidos à luz da literatura atual, e pode-se concluir que

  8. Ambroxol as a pharmacological chaperone for mutant glucocerebrosidase.

    Science.gov (United States)

    Bendikov-Bar, Inna; Maor, Gali; Filocamo, Mirella; Horowitz, Mia

    2013-02-01

    Gaucher disease (GD) is characterized by accumulation of glucosylceramide in lysosomes due to mutations in the GBA1 gene encoding the lysosomal hydrolase β-glucocerebrosidase (GCase). The disease has a broad spectrum of phenotypes, which were divided into three different Types; Type 1 GD is not associated with primary neurological disease while Types 2 and 3 are associated with central nervous system disease. GCase molecules are synthesized on endoplasmic reticulum (ER)-bound polyribosomes, translocated into the ER and following modifications and correct folding, shuttle to the lysosomes. Mutant GCase molecules, which fail to fold correctly, undergo ER associated degradation (ERAD) in the proteasomes, the degree of which is one of the factors that determine GD severity. Several pharmacological chaperones have already been shown to assist correct folding of mutant GCase molecules in the ER, thus facilitating their trafficking to the lysosomes. Ambroxol, a known expectorant, is one such chaperone. Here we show that ambroxol increases both the lysosomal fraction and the enzymatic activity of several mutant GCase variants in skin fibroblasts derived from Type 1 and Type 2 GD patients. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Degradation of AF1Q by chaperone-mediated autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Ji, Min; Lu, Fei; Zhang, Jingru [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Li, Huanjie; Cui, Taixing; Li Wang, Xing [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Tang, Dongqi, E-mail: tangdq@sdu.edu.cn [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Center for Stem Cell and Regenerative Medicine, The Second Hospital of Shandong University, Jinan 250033 (China); Ji, Chunyan, E-mail: jichunyan@sdu.edu.cn [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China)

    2014-09-10

    AF1Q, a mixed lineage leukemia gene fusion partner, is identified as a poor prognostic biomarker for pediatric acute myeloid leukemia (AML), adult AML with normal cytogenetic and adult myelodysplastic syndrome. AF1Q is highly regulated during hematopoietic progenitor differentiation and development but its regulatory mechanism has not been defined clearly. In the present study, we used pharmacological and genetic approaches to influence chaperone-mediated autophagy (CMA) and explored the degradation mechanism of AF1Q. Pharmacological inhibitors of lysosomal degradation, such as chloroquine, increased AF1Q levels, whereas activators of CMA, including 6-aminonicotinamide and nutrient starvation, decreased AF1Q levels. AF1Q interacts with HSPA8 and LAMP-2A, which are core components of the CMA machinery. Knockdown of HSPA8 or LAMP-2A increased AF1Q protein levels, whereas overexpression showed the opposite effect. Using an amino acid deletion AF1Q mutation plasmid, we identified that AF1Q had a KFERQ-like motif which was recognized by HSPA8 for CMA-dependent proteolysis. In conclusion, we demonstrate for the first time that AF1Q can be degraded in lysosomes by CMA. - Highlights: • Chaperone-mediated autophagy (CMA) is involved in the degradation of AF1Q. • Macroautophagy does not contribute to the AF1Q degradation. • AF1Q has a KFERQ-like motif that is recognized by CMA core components.

  10. Cellular chaperones and folding enzymes are vital contributors to membrane bound replication and movement complexes during plant RNA virus infection.

    Directory of Open Access Journals (Sweden)

    Jeanmarie eVerchot

    2012-12-01

    Full Text Available Cellular chaperones and folding enzymes play central roles in the formation of positive strand and negative strand RNA virus infection. This article examines the key cellular chaperones and discusses evidence that these factors are diverted from their cellular functions to play alternative roles in virus infection. For most chaperones discussed, their primary role in the cell is to ensure protein quality control. They are system components that drive substrate protein folding, complex assembly or disaggregation. Their activities often depend upon co-chaperones and ATP hydrolysis. During plant virus infection, Hsp70 and Hsp90 proteins play central roles in the formation of membrane bound replication complexes for certain members of the tombusvirus, tobamovirus, potyvirus, dianthovirus, potexvirus, and carmovirus genus. There are several co-chaperones, including Yjd1, RME-8 and Hsp40 that associate with the bromovirus replication complex, pomovirus TGB2, and tospovirus Nsm movement proteins. There are also examples of plant viruses that rely on chaperone systems in the endoplasmic reticulum (ER to support cell-to-cell movement. TMV relies on calreticulin to promote virus intercellular transport. Calreticulin also resides in the plasmodesmata and plays a role in calcium sequestration as well as glycoprotein folding. The pomovirus TGB2 interacts with RME-8 in the endosome. The potexvirus TGB3 protein stimulates expression of ER resident chaperones via the bZIP60 transcription factor. Upregulating factors involved in protein folding may be essential to handling the load of viral proteins translated along the ER. In addition TGB3 stimulates SKP1 which is a co-factor in proteasomal degradation of cellular proteins. Such chaperones and co-factors are potential targets for antiviral defense.

  11. Single molecule DNA interaction kinetics of retroviral nucleic acid chaperone proteins

    Science.gov (United States)

    Williams, Mark

    2010-03-01

    Retroviral nucleocapsid (NC) proteins are essential for several viral replication processes including specific genomic RNA packaging and reverse transcription. The nucleic acid chaperone activity of NC facilitates the latter process. In this study, we use single molecule biophysical methods to quantify the DNA interactions of wild type and mutant human immunodeficiency virus type 1 (HIV-1) NC and Gag and human T-cell leukemia virus type 1 (HTLV-1) NC. We find that the nucleic acid interaction properties of these proteins differ significantly, with HIV-1 NC showing rapid protein binding kinetics, significant duplex destabilization, and strong DNA aggregation, all properties that are critical components of nucleic acid chaperone activity. In contrast, HTLV-1 NC exhibits significant destabilization activity but extremely slow DNA interaction kinetics and poor aggregating capability, which explains why HTLV-1 NC is a poor nucleic acid chaperone. To understand these results, we developed a new single molecule method for quantifying protein dissociation kinetics, and applied this method to probe the DNA interactions of wild type and mutant HIV-1 and HTLV-1 NC. We find that mutations to aromatic and charged residues strongly alter the proteins' nucleic acid interaction kinetics. Finally, in contrast to HIV-1 NC, HIV-1 Gag, the nucleic acid packaging protein that contains NC as a domain, exhibits relatively slow binding kinetics, which may negatively impact its ability to act as a nucleic acid chaperone.

  12. Wound Healing Activity of a New Formulation from Platelet Lysate

    OpenAIRE

    Akram Jamshidzadeh; Omid Koohi Hosseinabadi; Reza Heidari; Soliman Mohammadi-Samani; Sara Rajabzadeh; Seyed Mojtaba Seyed Raoufi; Alireza Ahmadi Vadeghani

    2016-01-01

    Platelet-rich plasma (PRP) is an attractive preparation in regenerative medicine due to its potential role in the healing process in different experimental models. This study was designed to investigate the wound healing activity of a new formulation of PRP. Different gel-based formulations of PRP were prepared. Open excision wounds were made on the back of male Sprague-Dawley rats, and PRP gel was administered topically once daily until the wounds healed completely (12 days). The results rev...

  13. Intraarticular Injections of Platelet-rich Plasma (PRP) in the Management of Knee Osteoarthritis.

    Science.gov (United States)

    Rodriguez-Merchan, E Carlos

    2013-09-01

    The clinical use of PRP therapy in the practical setting of orthopaedic fields is increasing partly because of the accessibility of devices that are used in outpatient preparation and delivery. Another reason is the strong advertisement of PRP procedures as the ultimate treatment and novel technology for knee problems by a few orthopaedic surgeons based on claims of abundant scientific evidence. Hence, PubMed articles related to the clinical use of PRP in knee osteoarthritis were searched using the key words: PRP, knee and osteoarthritis in order to study these claims. A total of 20 reports were found directly related to the topic. The aforementioned clinical studies suggest that intraarticular injections of PRP could have preventive effects against osteoarthritis progression. However, presently there is no clear evidence from well-designed clinical trials that intraarticular injections of PRP are efficacious in osteoarthritis. Therefore, at this time the efficacy of PRP requires more investigation, wherein better scientific studies should be performed that include high powered randomized controlled trials.

  14. Augmenting tendon and ligament repair with platelet-rich plasma (PRP)

    Science.gov (United States)

    Yuan, Ting; Zhang, Chang-Qing; Wang, James H-C.

    2013-01-01

    Summary Tendon and ligament injuries (TLI) commonly occur in athletes and non-athletes alike, and remarkably debilitate patients’ athletic and personal abilities. Current clinical treatments, such as reconstruction surgeries, do not adequately heal these injuries and often result in the formation of scar tissue that is prone to re-injury. Platelet-rich plasma (PRP) is a widely used alternative option that is also safe because of its autologous nature. PRP contains a number of growth factors that are responsible for its potential to heal TLIs effectively. In this review, we provide a comprehensive report on PRP. While basic science studies in general indicate the potential of PRP to treat TLIs effectively, a review of existing literature on the clinical use of PRP for the treatment of TLIs indicates a lack of consensus due to varied treatment outcomes. This suggests that current PRP treatment protocols for TLIs may not be optimal, and that not all TLIs may be effectively treated with PRP. Certainly, additional basic science studies are needed to develop optimal treatment protocols and determine those TLI conditions that can be treated effectively. PMID:24367773

  15. A conserved co-chaperone is required for virulence in fungal plant pathogens.

    Science.gov (United States)

    Lo Presti, Libera; López Díaz, Cristina; Turrà, David; Di Pietro, Antonio; Hampel, Martin; Heimel, Kai; Kahmann, Regine

    2016-02-01

    The maize pathogenic fungus Ustilago maydis experiences endoplasmic reticulum (ER) stress during plant colonization and relies on the unfolded protein response (UPR) to cope with this stress. We identified the U. maydis co-chaperone, designated Dnj1, as part of this conserved cellular response to ER stress. ∆dnj1 cells are sensitive to the ER stressor tunicamycin and display a severe virulence defect in maize infection assays. A dnj1 mutant allele unable to stimulate the ATPase activity of chaperones phenocopies the null allele. A Dnj1-mCherry fusion protein localizes in the ER and interacts with the luminal chaperone Bip1. The Fusarium oxysporum Dnj1 ortholog contributes to the virulence of this fungal pathogen in tomato plants. Unlike the human ortholog, F. oxysporum Dnj1 partially rescues the virulence defect of the Ustilago dnj1 mutant. By enabling the fungus to restore ER homeostasis and maintain a high secretory activity, Dnj1 contributes to the establishment of a compatible interaction with the host. Dnj1 orthologs are present in many filamentous fungi, but are absent in budding and fission yeasts. We postulate a conserved and essential role during virulence for this class of co-chaperones. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  16. Autologous US-guided PRP injection versus US-guided focal extracorporeal shock wave therapy for chronic lateral epicondylitis: A minimum of 2-year follow-up retrospective comparative study.

    Science.gov (United States)

    Alessio-Mazzola, Mattia; Repetto, Ilaria; Biti, Besmir; Trentini, Roberto; Formica, Matteo; Felli, Lamberto

    2018-01-01

    To compare the efficacy of two independent groups of patients treated with ultrasound (US)-guided extracorporeal shock wave (ESW) therapy and with US-guided injection of platelet-rich plasma (PRP) for chronic lateral epicondylitis (LE) with a minimum of 2-year follow-up. We retrospectively evaluated 63 patients treated for chronic LE (31 patients with autologous US-guided PRP injection and 32 patients with US-guided focal ESW therapy) from 2009 to 2014. All the patients were evaluated by means of Roles-Maudsley (RM) score, quick Disabilities of Arm, Shoulder, and Hand (QuickDASH) score, visual analogic scale (VAS) and patient-rated tennis elbow evaluation (PRTEE) to retrospectively assess the pain relief, level of activity, the self-reported function and subjective satisfaction at minimum of 2-year follow-up. Both US-guided autologous PRP injection and US-guided focal ESW administration proved effective in chronic LE with significant improvement in the QuickDASH, VAS, RM and PRTEE scores ( p 0.05). The mean time between treatment and symptom resolution was significantly shorter for the PRP treatment ( p = 0.0212); furthermore, the mean time to return to the normal activities was quicker for PRP group ( p = 0.0119). Both PRP injection and ESW therapy are feasible and safe options for the treatment of chronic LE with low risk of complications and with good long-term follow-up results. US-guided PRP injection has quick efficacy when compared with US-guided focal ESW therapy.

  17. Specific Hsp100 Chaperones Determine the Fate of the First Enzyme of the Plastidial Isoprenoid Pathway for Either Refolding or Degradation by the Stromal Clp Protease in Arabidopsis.

    Science.gov (United States)

    Pulido, Pablo; Llamas, Ernesto; Llorente, Briardo; Ventura, Salvador; Wright, Louwrance P; Rodríguez-Concepción, Manuel

    2016-01-01

    The lifespan and activity of proteins depend on protein quality control systems formed by chaperones and proteases that ensure correct protein folding and prevent the formation of toxic aggregates. We previously found that the Arabidopsis thaliana J-protein J20 delivers inactive (misfolded) forms of the plastidial enzyme deoxyxylulose 5-phosphate synthase (DXS) to the Hsp70 chaperone for either proper folding or degradation. Here we show that the fate of Hsp70-bound DXS depends on pathways involving specific Hsp100 chaperones. Analysis of individual mutants for the four Hsp100 chaperones present in Arabidopsis chloroplasts showed increased levels of DXS proteins (but not transcripts) only in those defective in ClpC1 or ClpB3. However, the accumulated enzyme was active in the clpc1 mutant but inactive in clpb3 plants. Genetic evidence indicated that ClpC chaperones might be required for the unfolding of J20-delivered DXS protein coupled to degradation by the Clp protease. By contrast, biochemical and genetic approaches confirmed that Hsp70 and ClpB3 chaperones interact to collaborate in the refolding and activation of DXS. We conclude that specific J-proteins and Hsp100 chaperones act together with Hsp70 to recognize and deliver DXS to either reactivation (via ClpB3) or removal (via ClpC1) depending on the physiological status of the plastid.

  18. The Unfolded Protein Response and Chemical Chaperones Reduce Protein Misfolding and Colitis in Mice

    Science.gov (United States)

    CAO, STEWART SIYAN; ZIMMERMANN, ELLEN M.; CHUANG, BRANDY–MENGCHIEH; SONG, BENBO; NWOKOYE, ANOSIKE; WILKINSON, J. ERBY; EATON, KATHRYN A.; KAUFMAN, RANDAL J.

    2013-01-01

    BACKGROUND & AIMS Endoplasmic reticulum (ER) stress has been associated with development of inflammatory bowel disease. We examined the effects of ER stress–induced chaperone response and the orally active chemical chaperones tauroursodeoxycholate (TUDCA) and 4-phenylbutyrate (PBA), which facilitate protein folding and reduce ER stress, in mice with colitis. METHODS We used dextran sulfate sodium (DSS) to induce colitis in mice that do not express the transcription factor ATF6α or the protein chaperone P58IPK. We examined the effects of TUDCA and PBA in cultured intestinal epithelial cells (IECs); in wild-type, P58IPK−/−, and Atf6α−/− mice with colitis; and in Il10−/− mice. RESULTS P58IPK−/− and Atf6α−/− mice developed more severe colitis following administration of DSS than wild-type mice. IECs from P58IPK−/− mice had excessive ER stress, and apoptotic signaling was activated in IECs from Atf6α−/− mice. Inflammatory stimuli induced ER stress signals in cultured IECs, which were reduced by incubation with TUDCA or PBA. Oral administration of either PBA or TUDCA reduced features of DSS-induced acute and chronic colitis in wild-type mice, the colitis that develops in Il10−/− mice, and DSS-induced colitis in P58IPK−/− and Atf6α−/− mice. Reduced signs of colonic inflammation in these mice were associated with significantly decreased ER stress in colonic epithelial cells. CONCLUSIONS The unfolded protein response induces expression of genes that encode chaperones involved in ER protein folding; these factors prevent induction of colitis in mice. Chemical chaperones such as TUDCA and PBA alleviate different forms of colitis in mice and might be developed for treatment of inflammatory bowel diseases. PMID:23336977

  19. [Preparation of anticolon carcinoma vaccine with rich chaperone peptides and study on its anticancer efficacy].

    Science.gov (United States)

    Zhao, Jian-Gang; Huang, Chang-Xin; Yang, Guan-Gen; Jin, Jian-Fang; Kang, Yun-Ping; Xia, Da-Jing; Wang, Qing-Qing

    2009-05-01

    To prepare the anticolon carcinoma vaccine with rich chaperone peptide and to examine its anticancer immunological efficacy. CT26 colon carcinoma cells were cultured in 1 mg/L Trichosanthin 1640 medium at different temperatures to induce the chaperone expression and promote the synthesis of antigen peptides. Groups of these cells treated under the different condition were lysed by the sonic disintegration, and the lysates were centrifuged. The rawpurified proteins were obtained from the supernatants by precipitating with saturated ammonium sulfate and removing the molecules below 50,000 and above 300,000 in molecular weight via dialysis. Furthermore, the proteins with the molecular weights in 70,000, 90,000, 95,000, 110,000 and 170,000 were collected through gel filtration and SDS-PAGE. The purified proteins were analysed by Western blotting, and inspected on the anticancer immunological effects including lymphocyte proliferation and the activities of NK and CTL. Major of the chaperone peptides of anticancer effects in CT26 cells, including antigen peptides joining with HSP70, HSP90, gp96, HSP110 and HSP170, was satisfactorily extracted and condensed, and rich chaperone peptide composites were successfully obtained. The composites prepared under various condition could all enhance lymphocyte proliferation and the activities of CTL and NK(P<0.01). The rich chaperone peptide composites are successfully prepared via dialysis, salt fractionation and gel filtration combined with SDS-PAGE. Both the heat stress and Trichosanthin can increase the composites, which treated by 42 centi-degree heat stress and Trichosanthin are found to possess the strongest anticancer efficacy.

  20. Bacterial proteostasis balances energy and chaperone utilization efficiently

    Science.gov (United States)

    Santra, Mantu; Farrell, Daniel W.; Dill, Ken A.

    2017-01-01

    Chaperones are protein complexes that help to fold and disaggregate a cell’s proteins. It is not understood how four major chaperone systems of Escherichia coli work together in proteostasis: the recognition, sorting, folding, and disaggregating of the cell’s many different proteins. Here, we model this machine. We combine extensive data on chaperoning, folding, and aggregation rates with expression levels of proteins and chaperones measured at different growth rates. We find that the proteostasis machine recognizes and sorts a client protein based on two biophysical properties of the client’s misfolded state (M state): its stability and its kinetic accessibility from its unfolded state (U state). The machine is energy-efficient (the sickest proteins use the most ATP-expensive chaperones), comprehensive (it can handle any type of protein), and economical (the chaperone concentrations are just high enough to keep the whole proteome folded and disaggregated but no higher). The cell needs higher chaperone levels in two situations: fast growth (when protein production rates are high) and very slow growth (to mitigate the effects of protein degradation). This type of model complements experimental knowledge by showing how the various chaperones work together to achieve the broad folding and disaggregation needs of the cell. PMID:28292901

  1. Presence of chaperones during pelvic examinations in southeast ...

    African Journals Online (AJOL)

    Objectives: To assess the opinions, attitude, and preferences of Nigerian women to the presence of chaperones during pelvic examinations. Materials and Methods: A cross‑sectional survey of first time gynecology clinic attendees on their opinions, attitudes, and preferences with respect to the presence of chaperones ...

  2. Mitochondrial chaperones may be targets for anti-cancer drugs

    Science.gov (United States)

    Scientists at NCI have found that a mitochondrial chaperone protein, TRAP1, may act indirectly as a tumor suppressor as well as a novel target for developing anti-cancer drugs. Chaperone proteins, such as TRAP1, help other proteins adapt to stress, but sc

  3. Disaggregases, molecular chaperones that resolubilize protein aggregates

    Directory of Open Access Journals (Sweden)

    David Z. Mokry

    2015-08-01

    Full Text Available The process of folding is a seminal event in the life of a protein, as it is essential for proper protein function and therefore cell physiology. Inappropriate folding, or misfolding, can not only lead to loss of function, but also to the formation of protein aggregates, an insoluble association of polypeptides that harm cell physiology, either by themselves or in the process of formation. Several biological processes have evolved to prevent and eliminate the existence of non-functional and amyloidogenic aggregates, as they are associated with several human pathologies. Molecular chaperones and heat shock proteins are specialized in controlling the quality of the proteins in the cell, specifically by aiding proper folding, and dissolution and clearance of already formed protein aggregates. The latter is a function of disaggregases, mainly represented by the ClpB/Hsp104 subfamily of molecular chaperones, that are ubiquitous in all organisms but, surprisingly, have no orthologs in the cytosol of metazoan cells. This review aims to describe the characteristics of disaggregases and to discuss the function of yeast Hsp104, a disaggregase that is also involved in prion propagation and inheritance.

  4. The use of monoclonal antibody epitopes for tagging PrP in conversion experiments.

    Science.gov (United States)

    Vorberg, I; Pfaff, E; Groschup, M H

    2000-01-01

    The key event in the pathogenesis of spongiform encephalopathies is a conformational transition of a normal cellular protein, PrPsen, to its pathological isoform, PrPres. The mechanism of PrPres formation is unknown but is likely to involve a direct interaction between PrPsen and PrPres. The molecular basis of PrPres formation has been studied extensively using transgenic mice and scrapie-infected tissue cultures that express heterologous PrP molecules. However, these experiments are dependant on the discrimination of endogenous host PrP and exogenous PrP molecules. Here we give a short review on the PrP-specific epitopes that have been used for tagging exogenous PrP molecules and present a novel PrP-specific epitope that is well suitable for in vivo and in vitro conversion experiments.

  5. Role of Ultrasound Guided Platelet-Rich Plasma (PRP Injection in Treatment of Lateral Epicondylitis

    Directory of Open Access Journals (Sweden)

    Enass M. Khattab

    2017-06-01

    Conclusion: We concluded that US-guided platelet-rich plasma (PRP injection for treatment of lateral epicondylitis was a safe, minimally invasive and effective procedure in improving the sonographic and pathological changes of common extensor tendon (CET.

  6. Human Enterovirus Nonstructural Protein 2CATPase Functions as Both an RNA Helicase and ATP-Independent RNA Chaperone.

    Directory of Open Access Journals (Sweden)

    Hongjie Xia

    2015-07-01

    Full Text Available RNA helicases and chaperones are the two major classes of RNA remodeling proteins, which function to remodel RNA structures and/or RNA-protein interactions, and are required for all aspects of RNA metabolism. Although some virus-encoded RNA helicases/chaperones have been predicted or identified, their RNA remodeling activities in vitro and functions in the viral life cycle remain largely elusive. Enteroviruses are a large group of positive-stranded RNA viruses in the Picornaviridae family, which includes numerous important human pathogens. Herein, we report that the nonstructural protein 2CATPase of enterovirus 71 (EV71, which is the major causative pathogen of hand-foot-and-mouth disease and has been regarded as the most important neurotropic enterovirus after poliovirus eradication, functions not only as an RNA helicase that 3'-to-5' unwinds RNA helices in an adenosine triphosphate (ATP-dependent manner, but also as an RNA chaperone that destabilizes helices bidirectionally and facilitates strand annealing and complex RNA structure formation independently of ATP. We also determined that the helicase activity is based on the EV71 2CATPase middle domain, whereas the C-terminus is indispensable for its RNA chaperoning activity. By promoting RNA template recycling, 2CATPase facilitated EV71 RNA synthesis in vitro; when 2CATPase helicase activity was impaired, EV71 RNA replication and virion production were mostly abolished in cells, indicating that 2CATPase-mediated RNA remodeling plays a critical role in the enteroviral life cycle. Furthermore, the RNA helicase and chaperoning activities of 2CATPase are also conserved in coxsackie A virus 16 (CAV16, another important enterovirus. Altogether, our findings are the first to demonstrate the RNA helicase and chaperoning activities associated with enterovirus 2CATPase, and our study provides both in vitro and cellular evidence for their potential roles during viral RNA replication. These findings

  7. An improved freeze-dried PRP-coated biodegradable material suitable for connective tissue regenerative therapy.

    Science.gov (United States)

    Horimizu, Makoto; Kawase, Tomoyuki; Nakajima, Yu; Okuda, Kazuhiro; Nagata, Masaki; Wolff, Larry F; Yoshie, Hiromasa

    2013-06-01

    We previously published an investigation indicating freeze-dried platelet-rich plasma (PRP)-coated polyglactin mesh was a promising wound-dressing material. However, one of its disadvantages was the inflammatory nature due to degradation of the polyglactin. Therefore, in this study, we investigated the use of a collagen sponge as the carrier for PRP. When implanted subcutaneously in nude mice, the PRP-coated sponge alone rapidly induced angiogenesis and infiltration of surrounding connective tissue without inducing appreciable inflammation. Moreover, addition of periosteal fibroblastic cells substantially augmented the angiogenic response. With in vitro studies, the PRP-coated sponge provided various major growth factors at high levels to stimulate the proliferation of cells cultured on plastic dishes, but did not stimulate the proliferation of cells inoculated into the PRP-coated sponge. Cells were embedded in the fibrin mesh and maintained their spherical shape without stretching. The atomic force microscopic analysis demonstrated that the fibrin gel formed on the PRP-coated sponge was much softer (approx. 22 kPa) than the cross-linked collagen that formed the sponge base (appox. 1.9 MPa). Because insoluble matrices have recently and increasingly been considered important regulatory factors of cellular behavior, as are soluble growth factors, it is suggested that this soft fibrin mesh possibly suppresses cell survival. Overall, our investigation has successfully demonstrated improved wound-healing and regenerative potential of the PRP-coated mesh by combining it with the collagen sponge. In the clinical setting, this PRP-coated collagen sponge is a promising material for connective tissue regenerative therapy, such as periodontal therapy, burn victim treatment and in cosmetic or plastic surgery. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Differential effect of platelet-rich plasma fractions on β1-integrin signaling, collagen biosynthesis, and prolidase activity in human skin fibroblasts

    Science.gov (United States)

    Guszczyn, Tomasz; Surażyński, Arkadiusz; Zaręba, Ilona; Rysiak, Edyta; Popko, Janusz; Pałka, Jerzy

    2017-01-01

    The study was conducted to evaluate the effects of platelet-rich plasma (PRP), supernatant of PRP (SPRP) obtained by centrifugation, and supernatant of activated PRP (SActi-PRP) obtained by Ca2+ solution-treated PRP on collagen biosynthesis, prolidase activity, and β1-integrin signaling in cultured human skin fibroblasts. Incubation of fibroblasts with 5% PRP for 24 h contributed to ~5-fold increase in collagen biosynthesis compared to the control. In the cells treated with 5% of SPRP or SActi-PRP, collagen biosynthesis showed a 3-fold increase of the control. PRP, SPRP, and SActi-PRP stimulated prolidase activity similar to collagen biosynthesis. Collagen biosynthesis and prolidase activity are regulated by β1-integrin receptor signaling. Incubation of fibroblasts with PRP for 24 h contributed to a dose-dependent increase in the expression of β1-integrin receptor, while SActi-PRP increased the process to a much lower extent. SPRP had no effect on the β1-integrin receptor expression. All the studied fractions of blood increased the expression of FAK as well as the expression of phosphorylated MAP-kinases. However, PRP was found to be the most effective stimulator of expression of these particular kinases. These studies suggest that a complex of factors, including growth factors, adhesion molecules, and prolidase contained in PRP, all evoke growth and collagen-promoting activities in human dermal fibroblasts. PMID:28694685

  9. Evidence for alternative quaternary structure in a bacterial Type III secretion system chaperone

    Directory of Open Access Journals (Sweden)

    Picking Wendy L

    2010-07-01

    Full Text Available Abstract Background Type III secretion systems are a common virulence mechanism in many Gram-negative bacterial pathogens. These systems use a nanomachine resembling a molecular needle and syringe to provide an energized conduit for the translocation of effector proteins from the bacterial cytoplasm to the host cell cytoplasm for the benefit of the pathogen. Prior to translocation specialized chaperones maintain proper effector protein conformation. The class II chaperone, Invasion plasmid gene (Ipg C, stabilizes two pore forming translocator proteins. IpgC exists as a functional dimer to facilitate the mutually exclusive binding of both translocators. Results In this study, we present the 3.3 Å crystal structure of an amino-terminally truncated form (residues 10-155, denoted IpgC10-155 of the class II chaperone IpgC from Shigella flexneri. Our structure demonstrates an alternative quaternary arrangement to that previously described for a carboxy-terminally truncated variant of IpgC (IpgC1-151. Specifically, we observe a rotationally-symmetric "head-to- head" dimerization interface that is far more similar to that previously described for SycD from Yersinia enterocolitica than to IpgC1-151. The IpgC structure presented here displays major differences in the amino terminal region, where extended coil-like structures are seen, as opposed to the short, ordered alpha helices and asymmetric dimerization interface seen within IpgC1-151. Despite these differences, however, both modes of dimerization support chaperone activity, as judged by a copurification assay with a recombinant form of the translocator protein, IpaB. Conclusions From primary to quaternary structure, these results presented here suggest that a symmetric dimerization interface is conserved across bacterial class II chaperones. In light of previous data which have described the structure and function of asymmetric dimerization, our results raise the possibility that class II

  10. Evidence for alternative quaternary structure in a bacterial Type III secretion system chaperone

    Energy Technology Data Exchange (ETDEWEB)

    Barta, Michael L.; Zhang, Lingling; Picking, Wendy L.; Geisbrecht, Brian V. (UMKC); (OKLU)

    2010-10-05

    Type III secretion systems are a common virulence mechanism in many Gram-negative bacterial pathogens. These systems use a nanomachine resembling a molecular needle and syringe to provide an energized conduit for the translocation of effector proteins from the bacterial cytoplasm to the host cell cytoplasm for the benefit of the pathogen. Prior to translocation specialized chaperones maintain proper effector protein conformation. The class II chaperone, Invasion plasmid gene (Ipg) C, stabilizes two pore forming translocator proteins. IpgC exists as a functional dimer to facilitate the mutually exclusive binding of both translocators. In this study, we present the 3.3 {angstrom} crystal structure of an amino-terminally truncated form (residues 10-155, denoted IpgC10-155) of the class II chaperone IpgC from Shigella flexneri. Our structure demonstrates an alternative quaternary arrangement to that previously described for a carboxy-terminally truncated variant of IpgC (IpgC{sup 1-151}). Specifically, we observe a rotationally-symmetric 'head-to-head' dimerization interface that is far more similar to that previously described for SycD from Yersinia enterocolitica than to IpgC1-151. The IpgC structure presented here displays major differences in the amino terminal region, where extended coil-like structures are seen, as opposed to the short, ordered alpha helices and asymmetric dimerization interface seen within IpgC{sup 1-151}. Despite these differences, however, both modes of dimerization support chaperone activity, as judged by a copurification assay with a recombinant form of the translocator protein, IpaB. Conclusions: From primary to quaternary structure, these results presented here suggest that a symmetric dimerization interface is conserved across bacterial class II chaperones. In light of previous data which have described the structure and function of asymmetric dimerization, our results raise the possibility that class II chaperones may

  11. Interaction of new antidepressants with sigma-1 receptor chaperones and their potentiation of neurite outgrowth in PC12 cells.

    Science.gov (United States)

    Ishima, Tamaki; Fujita, Yuko; Hashimoto, Kenji

    2014-03-15

    The sigma-1 receptor chaperone located in the endoplasmic reticulum (ER) may be implicated in the mechanistic action of some antidepressants. The present study was undertaken to examine whether new antidepressant drugs interact with the sigma-1 receptor chaperone. First, we examined the effects of selective serotonin reuptake inhibitors (SSRIs) (fluvoxamine, paroxetine, sertraline, citalopram and escitalopram), serotonin and noradrenaline reuptake inhibitors (SNRIs) (duloxetine, venlafaxine, milnacipran), and mirtazapine, a noradrenaline and specific serotonergic antidepressant (NaSSA), on [(3)H](+)-pentazocine binding to rat brain membranes. Then, we examined the effects of these drugs on nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. The order of potency for drugs at the sigma-1 receptor chaperone was as follows: fluvoxamine>sertraline>fluoxetine>escitalopram>citalopram>paroxetine>duoxetine. Venlafaxine, milnacipran, and mirtazapine showed very weak affinity for this chaperone. Furthermore, fluvoxamine, fluoxetine, escitalopram, and mirtazapine significantly potentiated NGF-induced neurite outgrowth in cell assays, and the effects of all these drugs, excluding mirtazapine, were antagonized by NE-100, a selective antagonist of the sigma-1 receptor chaperone. Moreover, the effects of fluvoxamine and fluoxetine on neurite outgrowth were also antagonized by sertraline, indicating that sertraline may be an antagonist at the sigma-1 receptor chaperone. The effect of mirtazapine on neurite outgrowth was antagonized by the selective 5-hydroxytryptamine1A receptor antagonist WAY-100635. These findings suggest that activation at the sigma-1 receptor chaperone may be involved in the action of some SSRIs, such as fluvoxamine, fluoxetine and escitalopram. In contrast, mirtazapine independently potentiated neurite outgrowth in PC12 cells, indicating that this beneficial effect may mediate its pharmacological effect. Copyright © 2014 Elsevier B.V. All

  12. Polymorphisms at Amino Acid Residues 141 and 154 Influence Conformational Variation in Ovine PrP

    Directory of Open Access Journals (Sweden)

    Sujeong Yang

    2014-01-01

    Full Text Available Polymorphisms in ovine PrP at amino acid residues 141 and 154 are associated with susceptibility to ovine prion disease: Leu141Arg154 with classical scrapie and Phe141Arg154 and Leu141His154 with atypical scrapie. Classical scrapie is naturally transmissible between sheep, whereas this may not be the case with atypical scrapie. Critical amino acid residues will determine the range or stability of structural changes within the ovine prion protein or its functional interaction with potential cofactors, during conversion of PrPC to PrPSc in these different forms of scrapie disease. Here we computationally identified that regions of ovine PrP, including those near amino acid residues 141 and 154, displayed more conservation than expected based on local structural environment. Molecular dynamics simulations showed these conserved regions of ovine PrP displayed genotypic differences in conformational repertoire and amino acid side-chain interactions. Significantly, Leu141Arg154 PrP adopted an extended beta sheet arrangement in the N-terminal palindromic region more frequently than the Phe141Arg154 and Leu141His154 variants. We supported these computational observations experimentally using circular dichroism spectroscopy and immunobiochemical studies on ovine recombinant PrP. Collectively, our observations show amino acid residues 141 and 154 influence secondary structure and conformational change in ovine PrP that may correlate with different forms of scrapie.

  13. Cotton PRP5 gene encoding a proline-rich protein is involved in fiber development.

    Science.gov (United States)

    Xu, Wen-Liang; Zhang, De-Jing; Wu, Yan-Feng; Qin, Li-Xia; Huang, Geng-Qing; Li, Juan; Li, Long; Li, Xue-Bao

    2013-07-01

    Proline-rich proteins contribute to cell wall structure of specific cell types and are involved in plant growth and development. In this study, a fiber-specific gene, GhPRP5, encoding a proline-rich protein was functionally characterized in cotton. GhPRP5 promoter directed GUS expression only in trichomes of both transgenic Arabidopsis and tobacco plants. The transgenic Arabidopsis plants with overexpressing GhPRP5 displayed reduced cell growth, resulting in smaller cell size and consequently plant dwarfs, in comparison with wild type plants. In contrast, knock-down of GhPRP5 expression by RNA interference in cotton enhanced fiber development. The fiber length of transgenic cotton plants was longer than that of wild type. In addition, some genes involved in fiber elongation and wall biosynthesis of cotton were up-regulated or down-regulated in the transgenic cotton plants owing to suppression of GhPRP5. Collectively, these data suggested that GhPRP5 protein as a negative regulator participates in modulating fiber development of cotton.

  14. Parkinson disease-linked GBA mutation effects reversed by molecular chaperones in human cell and fly models

    Science.gov (United States)

    Sanchez-Martinez, Alvaro; Beavan, Michelle; Gegg, Matthew E.; Chau, Kai-Yin; Whitworth, Alexander J.; Schapira, Anthony H. V.

    2016-01-01

    GBA gene mutations are the greatest cause of Parkinson disease (PD). GBA encodes the lysosomal enzyme glucocerebrosidase (GCase) but the mechanisms by which loss of GCase contributes to PD remain unclear. Inhibition of autophagy and the generation of endoplasmic reticulum (ER) stress are both implicated. Mutant GCase can unfold in the ER and be degraded via the unfolded protein response, activating ER stress and reducing lysosomal GCase. Small molecule chaperones that cross the blood brain barrier help mutant GCase refold and traffic correctly to lysosomes are putative treatments for PD. We treated fibroblast cells from PD patients with heterozygous GBA mutations and Drosophila expressing human wild-type, N370S and L444P GBA with the molecular chaperones ambroxol and isofagomine. Both chaperones increased GCase levels and activity, but also GBA mRNA, in control and mutant GBA fibroblasts. Expression of mutated GBA in Drosophila resulted in dopaminergic neuronal loss, a progressive locomotor defect, abnormal aggregates in the ER and increased levels of the ER stress reporter Xbp1-EGFP. Treatment with both chaperones lowered ER stress and prevented the loss of motor function, providing proof of principle that small molecule chaperones can reverse mutant GBA-mediated ER stress in vivo and might prove effective for treating PD. PMID:27539639

  15. No associations between PrP genotypes and reproduction traits in INRA 401 sheep.

    Science.gov (United States)

    Vitezica, Z G; Moreno, C R; Bodin, L; François, D; Barillet, F; Brunel, J C; Elsen, J M

    2006-06-01

    In this study, the potential association of PrP genotypes with ewe reproductive traits and lamb growth traits was investigated. Data were included on ewes and lambs of the INRA 401 breed from the Bourges-La Sapinière INRA experimental farm. This breed was chosen because of good breeding (prolificacy and maternal abilities) and carcass qualities, and the large number of available animals with performance records and PrP genotypes. Ewes were categorized into 3 PrP genotype classes: ARR homozygous, ARR heterozygous, and animals without any ARR haplotype. Two analyses differing in the traits considered were carried out. Firstly, the potential association of the PrP genotype of ewes with their reproduction traits (fertility, litter size, and ovulation rate) was studied. The data included 801, 779, and 587 genotyped ewes for fertility, litter size, and ovulation rate, respectively. Secondly, the association of the PrP genotype of the ewes with growth traits of their lambs (birth weight, ADG between 10 and 30 d of age) was investigated. The data included 3,749 and 3,512 lambs for birth weight and ADG, respectively. The different traits were analyzed using an animal model, where the PrP genotype effect was included as a fixed effect. The reproductive traits were modeled under a probit or a threshold approach. The results of this study indicate no evidence of an association between PrP genotypes and reproductive and growth traits. It is unlikely that selection for scrapie resistance will have an effect on the reproductive or performance traits studied in the INRA 401 breed.

  16. Substrate and Substrate-Mimetic Chaperone Binding Sites in Human α-Galactosidase A Revealed by Affinity-Mass Spectrometry

    Science.gov (United States)

    Moise, Adrian; Maeser, Stefan; Rawer, Stephan; Eggers, Frederike; Murphy, Mary; Bornheim, Jeff; Przybylski, Michael

    2016-06-01

    Fabry disease (FD) is a rare metabolic disorder of a group of lysosomal storage diseases, caused by deficiency or reduced activity of the enzyme α-galactosidase. Human α-galactosidase A (hαGAL) hydrolyses the terminal α-galactosyl moiety from glycosphingolipids, predominantly globotriaosylceramide (Gb3). Enzyme deficiency leads to incomplete or blocked breakdown and progressive accumulation of Gb3, with detrimental effects on normal organ functions. FD is successfully treated by enzyme replacement therapy (ERT) with purified recombinant hαGAL. An emerging treatment strategy, pharmacologic chaperone therapy (PCT), employs small molecules that can increase and/or reconstitute the activity of lysosomal enzyme trafficking by stabilizing misfolded isoforms. One such chaperone, 1-deoxygalactonojirimycin (DGJ), is a structural galactose analogue currently validated in clinical trials. DGJ is an active-site-chaperone that binds at the same or similar location as galactose; however, the molecular determination of chaperone binding sites in lysosomal enzymes represents a considerable challenge. Here we report the identification of the galactose and DGJ binding sites in recombinant α-galactosidase through a new affinity-mass spectrometry-based approach that employs selective proteolytic digestion of the enzyme-galactose or -inhibitor complex. Binding site peptides identified by mass spectrometry, [39-49], [83-100], and [141-168], contain the essential ligand-contacting amino acids, in agreement with the known X-ray crystal structures. The inhibitory effect of DGJ on galactose recognition was directly characterized through competitive binding experiments and mass spectrometry. The methods successfully employed in this study should have high potential for the characterization of (mutated) enzyme-substrate and -chaperone interactions, and for identifying chaperones without inhibitory effects.

  17. Discovery of Benzisoxazoles as Potent Inhibitors of Chaperone Heat Shock Protein 90

    Energy Technology Data Exchange (ETDEWEB)

    Gopalsamy, Ariamala; Shi, Mengxiao; Golas, Jennifer; Vogan, Erik; Jacob, Jaison; Johnson, Mark; Lee, Frederick; Nilakantan, Ramaswamy; Petersen, Roseann; Svenson, Kristin; Chopra, Rajiv; Tam, May S.; Wen, Yingxia; Ellingboe, John; Arndt, Kim; Boschelli, Frank (Wyeth)

    2008-08-11

    Heat shock protein 90 (Hsp90) is a molecular chaperone that is responsible for activating many signaling proteins and is a promising target in tumor biology. We have identified small-molecule benzisoxazole derivatives as Hsp90 inhibitors. Crystallographic studies show that these compounds bind in the ATP binding pocket interacting with the Asp93. Structure based optimization led to the identification of potent analogues, such as 13, with good biochemical profiles.

  18. An Expanding Range of Functions for the Copper Chaperone/Antioxidant Protein Atox1

    OpenAIRE

    Hatori, Yuta; Lutsenko, Svetlana

    2013-01-01

    Significance: Antioxidant protein 1 (Atox1 in human cells) is a copper chaperone for the copper export pathway with an essential role in cellular copper distribution. In vitro, Atox1 binds and transfers copper to the copper-transporting ATPases, stimulating their catalytic activity. Inactivation of Atox1 in cells inhibits maturation of secreted cuproenzymes as well as copper export from cells. Recent Advances: Accumulating data suggest that cellular functions of Atox1 are not limited to its c...

  19. The N-terminal domain of the thermo-regulated surface protein PrpA of Enterococcus faecium binds to fibrinogen, fibronectin and platelets.

    Science.gov (United States)

    Guzmán Prieto, Ana M; Urbanus, Rolf T; Zhang, Xinglin; Bierschenk, Damien; Koekman, C Arnold; van Luit-Asbroek, Miranda; Ouwerkerk, Janneke P; Pape, Marieke; Paganelli, Fernanda L; Wobser, Dominique; Huebner, Johannes; Hendrickx, Antoni P A; Bonten, Marc J M; Willems, Rob J L; van Schaik, Willem

    2015-12-17

    Enterococcus faecium is a commensal of the mammalian gastrointestinal tract, but is also found in non-enteric environments where it can grow between 10 °C and 45 °C. E. faecium has recently emerged as a multi-drug resistant nosocomial pathogen. We hypothesized that genes involved in the colonization and infection of mammals exhibit temperature-regulated expression control and we therefore performed a transcriptome analysis of the clinical isolate E. faecium E1162, during mid-exponential growth at 25 °C and 37 °C. One of the genes that exhibited differential expression between 25 °C and 37 °C, was predicted to encode a peptidoglycan-anchored surface protein. The N-terminal domain of this protein is unique to E. faecium and closely related enterococci, while the C-terminal domain is homologous to the Streptococcus agalactiae surface protein BibA. This region of the protein contains proline-rich repeats, leading us to name the protein PrpA for proline-rich protein A. We found that PrpA is a surface-exposed protein which is most abundant during exponential growth at 37 °C in E. faecium E1162. The heterologously expressed and purified N-terminal domain of PrpA was able to bind to the extracellular matrix proteins fibrinogen and fibronectin. In addition, the N-terminal domain of PrpA interacted with both non-activated and activated platelets.

  20. COLLABORATIVE ACTION OF CELL CYCLE, MOLECULAR CHAPERONES, AND UBIQUITIN PROTEASOME SYSTEM IN NEUROONCOLOGY

    Directory of Open Access Journals (Sweden)

    Pravir Kumar

    2013-06-01

    Full Text Available he striking feature in tumor biology is uncontrolled cell proliferation and growth. Any alteration in the genetic make up may cause cell cycle deregulation that leads to aberrant cell cycle re-entry. These cascades ultimately cause cancerous situation with unwanted cell growth and division. There are several factors in cell cycle events that can lead to cancerous situations, for instance, checkpoint breach, extracellular signals, malfunctioned protein kinases, re-expression of cyclins and cyclin-CDKs complex. A crucial function of cyclinCDK complex is phosphorylation of retinoblastoma tumor suppressor gene that inhibits its ability to regulate the action of E2F transcription factor, which induces the gene expression and thus cause cell proliferation. To maintain the cellular homeostasis under tumorous condition, a line of protective mechanism is switched on such as availability of molecular chaperones; and if repair work fails, ubiquitin proteasome system comes in action. These regulatory mechanisms are highly conserved and play a critical role in maintaining several molecular events in the brain tumor or any stress situation. Misfolded proteins in tumor tissues are either rectified by chaperone activity upto a certain threshold or follow a degradation pathway by proteolytic activity of ubiquitinproteasome system. In this review, we have highlighted an extensive explorative potential of molecular chaperones in combination with ubiquitin E3 ligase enzymes activities in brain tumors.

  1. Conformational switching of the molecular chaperone Hsp90 via regulated phosphorylation.

    Science.gov (United States)

    Soroka, Joanna; Wandinger, Sebastian K; Mäusbacher, Nina; Schreiber, Thiemo; Richter, Klaus; Daub, Henrik; Buchner, Johannes

    2012-02-24

    Hsp90 is an essential molecular chaperone in the eukaryotic cytosol. Its function is modulated by cochaperones and posttranslational modifications. Importantly, the phosphatase Ppt1 is a dedicated regulator of the Hsp90 chaperone system. Little is known about Ppt1-dependent phosphorylation sites and how these affect Hsp90 activity. Here, we identified the major phosphorylation sites of yeast Hsp90 in its middle or the C-terminal domain and determined the subset regulated by Ppt1. In general, phosphorylation decelerates the Hsp90 machinery, reduces chaperone function in vivo, sensitizes yeast cells to Hsp90 inhibition and affects DNA repair processes. Modification of one particular site (S485) is lethal, whereas others modulate Hsp90 activity via distinct mechanisms affecting the ATPase activity, cochaperone binding and manipulating conformational transitions in Hsp90. Our mechanistic analysis reveals that phosphorylation of Hsp90 permits a regulation of the conformational cycle at distinct steps by targeting switch points for the communication of remote regions within Hsp90. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. The influence of using anticoagulants (EDTA and citrate acid 3.8% toward the quantity of Platelet Rich Plasma (PRP

    Directory of Open Access Journals (Sweden)

    Lilies Anggarwati Astuti

    2016-06-01

    Full Text Available Platelet Rich Plasma (PRP is a blood concentrate that has a thrombocytes concentration several time higher than normal concentration of thrombocytes in normal human blood. PRP is a promising alternative to surgery with a safe and natural healing. The standard protocol for PRP preparation must be determined to get the right quantity and quality of the matrix of fibrin, leukocytes, platelets and growth factors. It could not be separated from the number of PRP produced. The use of PRP in the success of periodontal treatment would not be separated from methods to obtain it. To detect the influence of using anticoagulants (EDTA and citrate acid 3.8% toward the quantity of PRP. There are 41 subjects studied by taking 21 ml of venous blood in each of the seven tubes. Centrifugation performed twice with different speed, duration, use of anticoagulants then analyzed. This quantity between the two groups differed significantly between the PRP in EDTA group is higher 322.2 ml rather than citrate acid 3.8% group, then control group is higher 329.5 ml rather than citrate acid 3.8% group, while there is no difference between EDTA and control group. There is effect of the use of anticoagulants EDTA compared with citrate acid 3.8% in the quantity of PRP, and there was no effect using citrate acid 3.8% as anticoagulants in quantity of PRP.

  3. The Hsp70/Hsp90 Chaperone Machinery in Neurodegenerative Diseases

    OpenAIRE

    Rachel E. Lackie; Rachel E. Lackie; Andrzej Maciejewski; Andrzej Maciejewski; Valeriy G. Ostapchenko; Jose Marques-Lopes; Wing-Yiu Choy; Martin L. Duennwald; Vania F. Prado; Vania F. Prado; Vania F. Prado; Vania F. Prado; Marco A. M. Prado; Marco A. M. Prado; Marco A. M. Prado

    2017-01-01

    The accumulation of misfolded proteins in the human brain is one of the critical features of many neurodegenerative diseases, including Alzheimer's disease (AD). Assembles of beta-amyloid (Aβ) peptide—either soluble (oligomers) or insoluble (plaques) and of tau protein, which form neurofibrillary tangles, are the major hallmarks of AD. Chaperones and co-chaperones regulate protein folding and client maturation, but they also target misfolded or aggregated proteins for refolding or for degrada...

  4. Biochemical characterization and cooperation with co-chaperones of heat shock protein 90 from Schizosaccharomyces pombe.

    Science.gov (United States)

    Ishida, Mari; Tomomari, Taichi; Kanzaki, Taro; Abe, Tetsuya; Oka, Toshihiko; Yohda, Masafumi

    2013-10-01

    The characterization of Hsp90 from the fission yeast Schizosaccharomyces pombe was performed. Hsp90 of S. pombe existed as a dimer and exhibited ATP-dependent conformational changes. It captured unfolded proteins in the ATP-free open conformation and protected them from thermal aggregation. Hsp90 of S. pombe was also able to refold thermally denatured firefly luciferase. The co-chaperones Sti1 and Aha1 bound Hsp90 and modulated its activity. Because the affinity of Sti1 was higher than that of Aha1, the effect of Sti1 appeared to dominate when both co-chaperones existed simultaneously. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. DEAD-box proteins as RNA helicases and chaperones

    Science.gov (United States)

    Jarmoskaite, Inga; Russell, Rick

    2010-01-01

    DEAD-box proteins are ubiquitous in RNA-mediated processes and function by coupling cycles of ATP binding and hydrolysis to changes in affinity for single-stranded RNA. Many DEAD-box proteins use this basic mechanism as the foundation for a version of RNA helicase activity, efficiently separating the strands of short RNA duplexes in a process that involves little or no translocation. This activity, coupled with mechanisms to direct different DEAD-box proteins to their physiological substrates, allows them to promote RNA folding steps and rearrangements and to accelerate remodeling of RNA-protein complexes. This review will describe the properties of DEAD-box proteins as RNA helicases and the current understanding of how the energy from ATPase activity is used to drive the separation of RNA duplex strands. It will then describe how the basic biochemical properties allow some DEAD-box proteins to function as chaperones by promoting RNA folding reactions, with a focus on the self-splicing group I and group II intron RNAs. PMID:21297876

  6. Chaperoning Roles of Macromolecules Interacting with Proteins in Vivo

    Directory of Open Access Journals (Sweden)

    Baik L. Seong

    2011-03-01

    Full Text Available The principles obtained from studies on molecular chaperones have provided explanations for the assisted protein folding in vivo. However, the majority of proteins can fold without the assistance of the known molecular chaperones, and little attention has been paid to the potential chaperoning roles of other macromolecules. During protein biogenesis and folding, newly synthesized polypeptide chains interact with a variety of macromolecules, including ribosomes, RNAs, cytoskeleton, lipid bilayer, proteolytic system, etc. In general, the hydrophobic interactions between molecular chaperones and their substrates have been widely believed to be mainly responsible for the substrate stabilization against aggregation. Emerging evidence now indicates that other features of macromolecules such as their surface charges, probably resulting in electrostatic repulsions, and steric hindrance, could play a key role in the stabilization of their linked proteins against aggregation. Such stabilizing mechanisms are expected to give new insights into our understanding of the chaperoning functions for de novo protein folding. In this review, we will discuss the possible chaperoning roles of these macromolecules in de novo folding, based on their charge and steric features.

  7. The use of a chaperone in obstetrical and gynaecological practice.

    LENUS (Irish Health Repository)

    Afaneh, I

    2012-02-01

    The aim of this study was to assess the use of a chaperone in obstetrical and gynaecological practice in Ireland and to explore patients\\' opinions. Two questionnaires were designed; one for patients and the other one was sent to 145 gynaecologists in Ireland. One hundred and fifty two women took part in this survey of whom 74 were gynaecological and 78 were obstetric patients. Ninety five (65%) patients felt no need for a chaperone during a vaginal examination (VE) by a male doctor. On the other hand 34 (23%) participating women would request a chaperone if being examined by a female doctor. Among clinicians 116 (80%) responded by returning the questionnaire. Overall 60 (52%) always used a chaperone in public practice, in contrast to 24 (27%) in private practice. The study demonstrated that most patients do not wish to have a chaperone during a VE but a small proportion would still request one regardless of the examiner\\'s gender. Patients should be offered the choice of having a chaperone and their opinion should be respected and documented.

  8. The use of a chaperone in obstetrical and gynaecological practice.

    LENUS (Irish Health Repository)

    Afaneh, I

    2010-05-01

    The aim of this study was to assess the use of a chaperone in obstetrical and gynaecological practice in Ireland and to explore patients\\' opinions. Two questionnaires were designed; one for patients and the other one was sent to 145 gynaecologists in Ireland. One hundred and fifty two women took part in this survey of whom 74 were gynaecological and 78 were obstetric patients. Ninety five (65%) patients felt no need for a chaperone during a vaginal examination (VE) by a male doctor. On the other hand 34 (23%) participating women would request a chaperone if being examined by a female doctor. Among clinicians 116 (80%) responded by returning the questionnaire. Overall 60 (52%) always used a chaperone in public practice, in contrast to 24 (27%) in private practice. The study demonstrated that most patients do not wish to have a chaperone during a VE but a small proportion would still request one regardless of the examiner\\'s gender. Patients should be offered the choice of having a chaperone and their opinion should be respected and documented.

  9. A primate specific extra domain in the molecular chaperone Hsp90.

    Directory of Open Access Journals (Sweden)

    Vishwadeepak Tripathi

    Full Text Available Hsp90 (heat shock protein 90 is an essential molecular chaperone that mediates folding and quality control of client proteins. Many of them such as protein kinases, steroid receptors and transcription factors are involved in cellular signaling processes. Hsp90 undergoes an ATP hydrolysis dependent conformational cycle to assist folding of the client protein. The canonical Hsp90 shows a typical composition of three distinct domains and interacts with individual cochaperone partners such as Hop, Cdc37 and Aha1 (activator of Hsp90 ATPase that regulate the reaction cycle of the molecular chaperone. A bioinformatic survey identified an additional domain of 122 amino acids in front of the canonical Hsp90 sequence. This extra domain (E domain is specific to the Catarrhini or drooping nose monkeys, a subdivision of the higher primates that includes man, the great apes and the old world monkeys but is absent from all other species. Our biochemical analysis reveals that Hsp103 associates with cochaperone proteins such as Hop, Cdc37 and Aha1 similar to Hsp90. However, the extra domain reduces the ATP hydrolysis rate to about half when compared to Hsp90 thereby acting as a negative regulator of the molecular chaperonés intrinsic ATPase activity.

  10. Brucella alters the immune response in a prpA-dependent manner

    Science.gov (United States)

    Spera, Juan M.; Comerci, Diego J.; Ugalde, Juan E.

    2014-01-01

    Brucellosis, a disease caused by the gram-negative bacterium Brucella sp, is a widespread zoonosis that inflicts important animal and human health problems, especially in developing countries. One of the hallmarks of Brucella infection is its capacity to establish a chronic infection, characteristic that depends on a wide repertoire of virulence factors among which are immunomodulatory proteins such as PrpA (encoding the proline racemase protein A or hydroxyproline-2-epimerase), involved in the establishment of the chronic phase of the infectious process that we have previously identified and characterized. We report here that, in vivo, B. abortus prpA is responsible for an increment in the B-cell number and in the specific antibody response and that these antibodies promote cell infection. We additionally found that Brucella alters the cytokine levels of IFN-γ, IL-10, TGFβ1 and TNFα during the acute phase of the infectious process in a prpA dependent manner. PMID:24508400

  11. Anaesthetics, steroids and platelet-rich plasma (PRP) in ultrasound-guided musculoskeletal procedures

    Science.gov (United States)

    La Marra, Alice; Arrigoni, Francesco; Mariani, Silvia; Zugaro, Luigi; Splendiani, Alessandra; Di Cesare, Ernesto; Reginelli, Alfonso; Zappia, Marcello; Brunese, Luca; Duka, Ejona; Carrafiello, Giampaolo; Masciocchi, Carlo

    2016-01-01

    This review aims to evaluate the role of anaesthetics, steroids and platelet-rich plasma (PRP) employed with ultrasound-guided injection in the management of musculoskeletal pathology of the extremities. Ultrasound-guided injection represents an interesting and minimally invasive solution for the treatment of tendon and joint inflammatory or degenerative diseases. The availability of a variety of new drugs such as hyaluronic acid and PRP provides expansion of the indications and therapeutic possibilities. The clinical results obtained in terms of pain reduction and functional recovery suggest that the use of infiltrative procedures can be a good therapeutic alternative in degenerative and inflammatory joint diseases. PMID:27302491

  12. IMPACT OF NATURAL FERTILIZATION USING PRP FIX ON SOME SOIL FERTILITY INDICATORS

    OpenAIRE

    Ewa Możdżer; Justyna Chudeka

    2017-01-01

    The field experiment was carried out at The Experimental Station of Plant Varieties Protection in Szczecin Dąbie. The experiment aimed at evaluating the influence of slurry with and without increasing doses of PRP FIX preparation on some soil fertility indicators after test plants harvest. Contents of determined macronutrients in the soil were higher in objects where slurry was applied with addition of 8 kg or 12 kg of PRP FIX per 1 m3 as compared to those with exclusively mineral fertiliz...

  13. Structural and functional characterization of Pseudomonas aeruginosa CupB chaperones.

    Directory of Open Access Journals (Sweden)

    Xun Cai

    Full Text Available Pseudomonas aeruginosa, an important human pathogen, is estimated to be responsible for ∼10% of nosocomial infections worldwide. The pathogenesis of P. aeruginosa starts from its colonization in the damaged tissue or medical devices (e.g. catheters, prothesis and implanted heart valve etc. facilitated by several extracellular adhesive factors including fimbrial pili. Several clusters containing fimbrial genes have been previously identified on the P. aeruginosa chromosome and named cup[1]. The assembly of the CupB pili is thought to be coordinated by two chaperones, CupB2 and CupB4. However, due to the lack of structural and biochemical data, their chaperone activities remain speculative. In this study, we report the 2.5 Å crystal structure of P. aeruginosa CupB2. Based on the structure, we further tested the binding specificity of CupB2 and CupB4 towards CupB1 (the presumed major pilus subunit and CupB6 (the putative adhesin using limited trypsin digestion and strep-tactin pull-down assay. The structural and biochemical data suggest that CupB2 and CupB4 might play different, but not redundant, roles in CupB secretion. CupB2 is likely to be the chaperone of CupB1, and CupB4 could be the chaperone of CupB4:CupB5:CupB6, in which the interaction of CupB4 and CupB6 might be mediated via CupB5.

  14. Molecular functions of the histone acetyltransferase chaperone complex Rtt109-Vps75

    Energy Technology Data Exchange (ETDEWEB)

    Berndsen, Christopher E; Tsubota, Toshiaki; Lindner, Scott E; Lee, Susan; Holton, James M; Kaufman, Paul D; Keck, James L; Denu, John M [UMASS, MED; (UCB); (UW-MED)

    2010-01-12

    Histone acetylation and nucleosome remodeling regulate DNA damage repair, replication and transcription. Rtt109, a recently discovered histone acetyltransferase (HAT) from Saccharomyces cerevisiae, functions with the histone chaperone Asf1 to acetylate lysine K56 on histone H3 (H3K56), a modification associated with newly synthesized histones. In vitro analysis of Rtt109 revealed that Vps75, a Nap1 family histone chaperone, could also stimulate Rtt109-dependent acetylation of H3K56. However, the molecular function of the Rtt109-Vps75 complex remains elusive. Here we have probed the molecular functions of Vps75 and the Rtt109-Vps75 complex through biochemical, structural and genetic means. We find that Vps75 stimulates the kcat of histone acetylation by {approx}100-fold relative to Rtt109 alone and enhances acetylation of K9 in the H3 histone tail. Consistent with the in vitro evidence, cells lacking Vps75 showed a substantial reduction (60%) in H3K9 acetylation during S phase. X-ray structural, biochemical and genetic analyses of Vps75 indicate a unique, structurally dynamic Nap1-like fold that suggests a potential mechanism of Vps75-dependent activation of Rtt109. Together, these data provide evidence for a multifunctional HAT-chaperone complex that acetylates histone H3 and deposits H3-H4 onto DNA, linking histone modification and nucleosome assembly.

  15. Hsp70/Hsp90 organising protein (hop): beyond interactions with chaperones and prion proteins.

    Science.gov (United States)

    Baindur-Hudson, Swati; Edkins, Adrienne L; Blatch, Gregory L

    2015-01-01

    The Hsp70/Hsp90 organising protein (Hop), also known as stress-inducible protein 1 (STI1), has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins. Consequently, Hop is implicated in a number of key signalling pathways, including aberrant pathways leading to cancer. However, Hop is also secreted and it is now well established that Hop also serves as a receptor for the prion protein, PrP(C). The intracellular and extracellular forms of Hop most likely represent two different isoforms, although the molecular determinants of these divergent functions are yet to be identified. There is also a growing body of research that reports the involvement of Hop in cellular activities that appear independent of either chaperones or PrP(C). While Hop has been shown to have various cellular functions, its biological function remains elusive. However, recent knockout studies in mammals suggest that Hop has an important role in embryonic development. This review provides a critical overview of the latest molecular, cellular and biological research on Hop, critically evaluating its function in healthy systems and how this function is adapted in diseases states.

  16. Structure of the human histone chaperone FACT Spt16 N-terminal domain

    Energy Technology Data Exchange (ETDEWEB)

    Marcianò, G.; Huang, D. T., E-mail: d.huang@beatson.gla.ac.uk [Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, Scotland (United Kingdom)

    2016-01-22

    The Spt16–SSRP1 heterodimer is a histone chaperone that plays an important role in regulating chromatin assembly. Here, a crystal structure of the N-terminal domain of human Spt16 is presented and it is shown that this domain may contribute to histone binding. The histone chaperone FACT plays an important role in facilitating nucleosome assembly and disassembly during transcription. FACT is a heterodimeric complex consisting of Spt16 and SSRP1. The N-terminal domain of Spt16 resembles an inactive aminopeptidase. How this domain contributes to the histone chaperone activity of FACT remains elusive. Here, the crystal structure of the N-terminal domain (NTD) of human Spt16 is reported at a resolution of 1.84 Å. The structure adopts an aminopeptidase-like fold similar to those of the Saccharomyces cerevisiae and Schizosaccharomyces pombe Spt16 NTDs. Isothermal titration calorimetry analyses show that human Spt16 NTD binds histones H3/H4 with low-micromolar affinity, suggesting that Spt16 NTD may contribute to histone binding in the FACT complex. Surface-residue conservation and electrostatic analysis reveal a conserved acidic patch that may be involved in histone binding.

  17. Schizosaccharomyces pombe disaggregation machinery chaperones support Saccharomyces cerevisiae growth and prion propagation.

    Science.gov (United States)

    Reidy, Michael; Sharma, Ruchika; Masison, Daniel C

    2013-05-01

    Hsp100 chaperones protect microorganisms and plants from environmental stress by cooperating with Hsp70 and its nucleotide exchange factor (NEF) and Hsp40 cochaperones to resolubilize proteins from aggregates. The Saccharomyces cerevisiae Hsp104 (Sc-Hsp104)-based disaggregation machinery also is essential for replication of amyloid-based prions. Escherichia coli ClpB can substitute for Hsp104 to propagate [PSI(+)] prions in yeast, but only if E. coli DnaK and GrpE (Hsp70 and NEF) are coexpressed. Here, we tested if the reported inability of Schizosaccharomyces pombe Hsp104 (Sp-Hsp104) to support [PSI(+)] propagation was due to similar species-specific chaperone requirements and find that Sp-Hsp104 alone supported propagation of three different yeast prions. Sp-Hsp70 and Sp-Fes1p (NEF) likewise functioned in place of their Sa. cerevisiae counterparts. Thus, chaperones of these long-diverged species possess conserved activities that function in processes essential for both cell growth and prion propagation, suggesting Sc. pombe can propagate its own prions. We show that curing by Hsp104 overexpression and inactivation can be distinguished and confirm the observation that, unlike Sc-Hsp104, Sp-Hsp104 cannot cure yeast of [PSI(+)] when it is overexpressed. These results are consistent with a view that mechanisms underlying prion replication and elimination are distinct.

  18. Sulphur shuttling across a chaperone during molybdenum cofactor maturation.

    Science.gov (United States)

    Arnoux, Pascal; Ruppelt, Christian; Oudouhou, Flore; Lavergne, Jérôme; Siponen, Marina I; Toci, René; Mendel, Ralf R; Bittner, Florian; Pignol, David; Magalon, Axel; Walburger, Anne

    2015-02-04

    Formate dehydrogenases (FDHs) are of interest as they are natural catalysts that sequester atmospheric CO2, generating reduced carbon compounds with possible uses as fuel. FDHs activity in Escherichia coli strictly requires the sulphurtransferase EcFdhD, which likely transfers sulphur from IscS to the molybdenum cofactor (Mo-bisPGD) of FDHs. Here we show that EcFdhD binds Mo-bisPGD in vivo and has submicromolar affinity for GDP-used as a surrogate of the molybdenum cofactor's nucleotide moieties. The crystal structure of EcFdhD in complex with GDP shows two symmetrical binding sites located on the same face of the dimer. These binding sites are connected via a tunnel-like cavity to the opposite face of the dimer where two dynamic loops, each harbouring two functionally important cysteine residues, are present. On the basis of structure-guided mutagenesis, we propose a model for the sulphuration mechanism of Mo-bisPGD where the sulphur atom shuttles across the chaperone dimer.

  19. Platelet-Rich Plasma Activates Proinflammatory Signaling Pathways and Induces Oxidative Stress in Tendon Fibroblasts.

    Science.gov (United States)

    Hudgens, Joshua L; Sugg, Kristoffer B; Grekin, Jeremy A; Gumucio, Jonathan P; Bedi, Asheesh; Mendias, Christopher L

    2016-08-01

    Tendon injuries are one of the most common musculoskeletal conditions in active patients. Platelet-rich plasma (PRP) has shown some promise in the treatment of tendon disorders, but little is known as to the mechanisms by which PRP can improve tendon regeneration. PRP contains numerous different growth factors and cytokines that activate various cellular signaling cascades, but it has been difficult to determine precisely which signaling pathways and cellular responses are activated after PRP treatment. Additionally, macrophages play an important role in modulating tendon regeneration, but the influence of PRP on determining whether macrophages assume a proinflammatory or anti-inflammatory phenotype remains unknown. To use genome-wide expression profiling, bioinformatics, and protein analysis to determine the cellular pathways activated in fibroblasts treated with PRP. The effect of PRP on macrophage polarization was also evaluated. Controlled laboratory study. Tendon fibroblasts or macrophages from rats were cultured and treated with either platelet-poor plasma (PPP) or PRP. RNA or protein was isolated from cells and analyzed using microarrays, quantitative polymerase chain reaction, immunoblotting, or bioinformatics techniques. Pathway analysis determined that the most highly induced signaling pathways in PRP-treated tendon fibroblasts were TNFα and NFκB pathways. PRP also downregulated the expression of extracellular matrix genes and induced the expression of autophagy-related genes and reactive oxygen species (ROS) genes and protein markers in tendon fibroblasts. PRP failed to have a major effect on markers of macrophage polarization. PRP induces an inflammatory response in tendon fibroblasts, which leads to the formation of ROS and the activation of oxidative stress pathways. PRP does not appear to significantly modulate macrophage polarization. PRP might act by inducing a transient inflammatory event, which could then trigger a tissue regeneration response

  20. A comparison between platelet-rich plasma (PRP and hyaluronate acid on the healing of cartilage defects.

    Directory of Open Access Journals (Sweden)

    Ji Liu

    Full Text Available Platelet-rich plasma (PRP has offered great promise for the treatment of cartilage degradation, and has been proved to have positive effects on the restoration of cartilage lesions. But no comparative work has been done between PRP and hyaluronate acid (HA concerning their restoring effect on cartilage defect, especially by means of animal experiments and histologic assessments. The purpose of the study was to compare the therapeutic effects of P-PRP and HA on osteoarthritis in rabbit knees. Thirty rabbits were used to establish the animal models by creating a cartilage defect of 5 mm in diameter on the condyles of the femurs, and were randomly divided into three groups: the P-PRP group, HA group and the control group. Then each group was treated with P-PRP, HA or saline solution, respectively. Six and twelve weeks later the rabbits were sacrificed and the samples were collected. The platelet number, the concentrations of growth factors of P-PRP and whole blood, and the IL-1β concentration in the joint fluid were investigated, and the histological assessment of the cartilage were performed according to Mankin's scoring system. Micro-CT was also used to evaluate the restoration of subchondral bone. The platelet concentration in P-PRP is 6.8 fold of that in the whole blood. The IL-1β level in the P-PRP group was lower than in the HA group (p<0.01 and in the control group (p<0.01. The restoration of the defected cartilage as well as the subchondral bone was better in the P-PRP group than in the HA group or the control group (P<0.05. Our data showed that P-PRP is better than HA in promoting the restoration of the cartilage and alleviating the arthritis caused by cartilage damage.

  1. Clinical effect of PRP combined with calcium dobesilate in treatment of patients with DR

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    Li-Bo Wang

    2017-09-01

    Full Text Available AIM: To investigate the clinical effect of panretinal photocoagulation(PRPcombined with calcium dobesilate in treatment of diabetic retinopathy(DR. METHODS: Selected 120 cases(240 eyesof DR diagnosed in our hospital from January 2011 to January 2016 were retrospectively analyzed. According to whether calcium dobesilate was used, the treatment group was divided into two groups. Sixty cases were treated with PRP combined with calcium dobesilate, and 60 cases in the control group were treated with PRP only. The BCVA, CMT and clinical efficacy of the two groups were compared. RESULTS: Before treatment, there was no significant difference on BCVA between combined group and control group(P>0.05. After treatment, BCVA of combined group was higher than that of the control group(PP>0.05; after treatment, the combination group on CMT, neovascularization and fluorescein leakage area value were less than the control group(PPCONCLUSION:PRP combined with calcium dobesilate in treatment of DR has a more significant clinical effect than PRP alone.

  2. The use of autologous PRP gel as an aid in the management of acute trauma wounds.

    Science.gov (United States)

    Kazakos, K; Lyras, D N; Verettas, D; Tilkeridis, K; Tryfonidis, M

    2009-08-01

    Autologous platelet-rich plasma (PRP) gel is increasingly used in the treatment of a variety of soft and bony tissue defects, such as accelerating bone formation and in the management of chronic non-healing wounds. We performed this study to assess the benefits of using autologous PRP gel in the treatment of acute limb soft tissue wounds. 59 patients with acute wounds (open fractures, closed fractures with skin necrosis and friction burns) were randomised into two groups. Group A (32 patients) were treated with conventional dressings and Group B (27 patients) were managed with local application of PRP gel. Gustillo grade IIIb or IIIc open fractures were not included in this study, as these injuries required coverage with flap. The clinical endpoints were the healing rate and/or the time required to bring about adequate tissue regeneration in order to undergo reconstructive plastic surgery. The rate of wound healing rate was significantly faster in Group B at week 1, 2 and 3 (p=0.003, p<0.001 and p<0.001, respectively). The mean time to plastic reconstruction in Group B was 21.26 days, S.D.=1.35 vs 40.6 days in Group A, S.D.=5.27 (p<0.001). This study has shown that PRP gel treatment can be a valuable and effective aid in the management of acute trauma wounds.

  3. Quantitating PrP polymorphisms present in prions from heterozygous scrapie-infected sheep

    Science.gov (United States)

    Scrapie is a prion (PrPSc) disease of sheep. The incubation period of sheep scrapie is strongly influenced by polymorphisms at positions 136, 154, and 171 of a sheep’s normal cellular prion protein (PrPC). Chymotrypsin was used to digest sheep recombinant PrP to identify a set of characteristic pept...

  4. Immunological mimicry of PrPC-PrPSc interactions: antibody-induced PrP misfolding.

    Science.gov (United States)

    Li, Li; Guest, Will; Huang, Alan; Plotkin, Steven S; Cashman, Neil R

    2009-08-01

    Prion diseases are associated with the conversion of cellular prion protein (PrP(C)) to an abnormal protease-resistant conformational isoform (PrP(Sc)) by template-directed conversion. The interaction between PrP(C) and PrP(Sc) is mediated by specific sites which have been mapped to six putative 'binding and conversion domains' (PrP-BCD) through peptide and antibody competition studies. Monoclonal antibodies (mAbs) directed against the bityrosine motif Tyr-Tyr-Arg (YYR) specifically recognize PrP(Sc) and other misfolded PrP species. Here, we report that select bead-bound PrP-BCD mAbs induce exposure of bityrosine epitopes on mouse brain PrP. By competition immunoprecipitation, we show that PrP-BCD mAb-induced bityrosine exposure occurs at alpha-helices 1 and 3. However, PrP-BCD mAb-induced PrP(C) misfolding is not accompanied by beta-sheet dissociation, a key event in PrP(C) conversion to PrP(Sc), and is not associated with acquisition of protease resistance, or the capacity to recruit additional molecules of PrP. Our data suggest that mAb mimics of the physical interaction of PrP(C) with PrP(Sc) can induce unfolding of specific PrP domains, but that subsequent processes (including the energetically unfavorable beta-sheet dissociation) effect isoform conversion in prion disease.

  5. Exceptions to the PRP Effect? A Comparison of Prepared and Unconditioned Reflexes

    Science.gov (United States)

    Janczyk, Markus; Pfister, Roland; Wallmeier, Gloria; Kunde, Wilfried

    2014-01-01

    Psychological research has documented again and again marked performance decrements whenever humans perform 2 or more tasks at the same time. In fact, the available evidence seems to suggest that any type of behavior is subject to such limitations. The present experiments employed the psychological refractory period (PRP) paradigm to identify a…

  6. No associations between PrP genotypes and reproduction traits in INRA 401 sheep

    National Research Council Canada - National Science Library

    Vitezica, Z. G; Moreno, C. R; Bodin, L; Francois, D; Barillet, F; Brunel, J. C; Elsen, J. M

    2006-01-01

    ...; and and INRA, Domaine de la Sapinière, 18390 Osmoy, France 2 Corresponding author: vitezica{at}germinal.toulouse.inra.fr In this study, the potential association of PrP genotypes with ewe reproductive traits and lamb growth traits was investigated...

  7. 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.

  8. On the importance of Task 1 and error performance measures in PRP dual-task studies

    Directory of Open Access Journals (Sweden)

    Tilo eStrobach

    2015-04-01

    Full Text Available The Psychological Refractory Period (PRP paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and 2 are presented with variable stimulus onset asynchronies (SOAs and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e. decreasing SOAs do not increase RTs and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/ or error rates in Task 1. This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  9. [Immunogenicity and safety of DTaP-IPV//PRP-T combined vaccine in infants in China].

    Science.gov (United States)

    Li, Yan-ping; Li, Feng-xiang; Hou, Qi-ming; Li, Chang-gui; Li, Ya-nan; Chen, Fu-sheng; Hu, Xue-zhong; Su, Wen-bin; Zhang, Shu-min; Fang, Han-hua; Ye, Qiang; Zeng, Tian-de; Liu, Tao-xuan; Li, Xiu-bi; Huang, Yun-neng; Deng, Man-ling; Li, Rong-cheng; Zhang, Yan-ping; Esteban, Ortiz

    2011-08-01

    The aim of this study was to demonstrate the immunogenicity and safety of diphtheria, tetanus, pertussis (acellular, component), poliomyelitis (inactivated) vaccine (adsorbed) and Haemophilus influenzae type b conjugate vaccine (DTaP-IPV//PRP-T) combined vaccine compared with commercially available DTaP (diphtheria, tetanus and pertussis), Haemophilus influenzae type b (Hib), tetanus conjugate and IPV monovalent vaccine. Subjects were randomly divided into three groups, Group A and Group B were DTaP-IPV//PRP-T combined vaccine (PENTAXIM(TM)) vaccinated at 2, 3, 4 months of age or 3, 4, 5 months of age respectively; Group C was commercially available DTaP. Hib tetanus conjugate (Act-HIB(TM)) and IPV (IMOVAX PolioTM(TM)) vaccines vaccinated at 3, 4, 5 months of age. All groups received booster dose at 18 to 20 months of age, with antibody titers tested. Non-inferiority analysis was demonstrated in terms of seroprotection/seroconversion rates between Group A, Group B respectively and Group C. Safety information was collected after each vaccination to assess the safety of investigational vaccines. The non-inferiority of DTaP-IPV//PRP-T combined vaccine vaccinated at 2, 3, 4 or 3, 4, 5 months of age versus DTaP, Hib tetanus conjugate and IPV vaccine was demonstrated for all vaccine antigens in both primary and booster phases in terms of seroprotection/seroconversion rates. DTaP-IPV//PRP-T combined vaccine was well tolerated. The rate of solicited/unsolicited severe adverse reactions was very low and similar to the control vaccines. DTaP-IPV//PRP-T combined vaccine was highly immunogenic with good safety profile in Chinese infants, which was comparable to the commercially available control vaccines.

  10. On the importance of Task 1 and error performance measures in PRP dual-task studies.

    Science.gov (United States)

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

    The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  11. The R/V Discoverer cruise to Manus Island. The BNL Portable Radiometer Package (PRP) evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, R.M.; Smith, S.

    1996-05-24

    Brookhaven National Laboratory installed and operated a Portable Radiation Package (PRP) on the NOAA ship R/V DISCOVERER as part of the Combined Sensor Program cruise in the Tropical Western Pacific Ocean. The DISCOVERER transported a collection of radiation and atmospheric instrumentation to positions offshore of manus Island to compare cloud and radiation fields to like instruments measured from a station on the island. The ship sailed NW from Pago Pago, American Samoa, on 14 March 1996 to a latitude of 1{degree}S then due West until it approached manus Island (2{degree}S and 148{degree}E) on approximately 7 April. The ship then turned SW and approached Manus Island in three steps. This route was reversed during the ship`s return to Hawaii. The PRP package is a compact low-power integration of simple sensors that measure long- and short-wave irradiance from moving platforms. A rapid rotating shadowband radiometer that is designed to provide good estimates of diffuse (sky) radiation even from moving buoys or ships was being evaluated. The PRP provided the only means of making diffuse (sky) radiation measurements from the ship. The CSP cruise provided an excellent opportunity to intercompare the PRP with other like instruments in the TWP locale. The unit was located on the starboard flying bridge which was fully exposed to direct sunlight during the ship`s westward transit. When the ship was at its closest approach to manus, the PRP was moved to the island where careful intercomparison with the Manus instrumentation was conducted.

  12. Atomistic simulations and network-based modeling of the Hsp90-Cdc37 chaperone binding with Cdk4 client protein: A mechanism of chaperoning kinase clients by exploiting weak spots of intrinsically dynamic kinase domains.

    Directory of Open Access Journals (Sweden)

    Josh Czemeres

    Full Text Available A fundamental role of the Hsp90 and Cdc37 chaperones in mediating conformational development and activation of diverse protein kinase clients is essential in signal transduction. There has been increasing evidence that the Hsp90-Cdc37 system executes its chaperoning duties by recognizing conformational instability of kinase clients and modulating their folding landscapes. The recent cryo-electron microscopy structure of the Hsp90-Cdc37-Cdk4 kinase complex has provided a framework for dissecting regulatory principles underlying differentiation and recruitment of protein kinase clients to the chaperone machinery. In this work, we have combined atomistic simulations with protein stability and network-based rigidity decomposition analyses to characterize dynamic factors underlying allosteric mechanism of the chaperone-kinase cycle and identify regulatory hotspots that control client recognition. Through comprehensive characterization of conformational dynamics and systematic identification of stabilization centers in the unbound and client- bound Hsp90 forms, we have simulated key stages of the allosteric mechanism, in which Hsp90 binding can induce instability and partial unfolding of Cdk4 client. Conformational landscapes of the Hsp90 and Cdk4 structures suggested that client binding can trigger coordinated dynamic changes and induce global rigidification of the Hsp90 inter-domain regions that is coupled with a concomitant increase in conformational flexibility of the kinase client. This process is allosteric in nature and can involve reciprocal dynamic exchanges that exert global effect on stability of the Hsp90 dimer, while promoting client instability. The network-based rigidity analysis and emulation of thermal unfolding of the Cdk4-cyclin D complex and Hsp90-Cdc37-Cdk4 complex revealed weak spots of kinase instability that are present in the native Cdk4 structure and are targeted by the chaperone during client recruitment. Our findings

  13. Atomistic simulations and network-based modeling of the Hsp90-Cdc37 chaperone binding with Cdk4 client protein: A mechanism of chaperoning kinase clients by exploiting weak spots of intrinsically dynamic kinase domains.

    Science.gov (United States)

    Czemeres, Josh; Buse, Kurt; Verkhivker, Gennady M

    2017-01-01

    A fundamental role of the Hsp90 and Cdc37 chaperones in mediating conformational development and activation of diverse protein kinase clients is essential in signal transduction. There has been increasing evidence that the Hsp90-Cdc37 system executes its chaperoning duties by recognizing conformational instability of kinase clients and modulating their folding landscapes. The recent cryo-electron microscopy structure of the Hsp90-Cdc37-Cdk4 kinase complex has provided a framework for dissecting regulatory principles underlying differentiation and recruitment of protein kinase clients to the chaperone machinery. In this work, we have combined atomistic simulations with protein stability and network-based rigidity decomposition analyses to characterize dynamic factors underlying allosteric mechanism of the chaperone-kinase cycle and identify regulatory hotspots that control client recognition. Through comprehensive characterization of conformational dynamics and systematic identification of stabilization centers in the unbound and client- bound Hsp90 forms, we have simulated key stages of the allosteric mechanism, in which Hsp90 binding can induce instability and partial unfolding of Cdk4 client. Conformational landscapes of the Hsp90 and Cdk4 structures suggested that client binding can trigger coordinated dynamic changes and induce global rigidification of the Hsp90 inter-domain regions that is coupled with a concomitant increase in conformational flexibility of the kinase client. This process is allosteric in nature and can involve reciprocal dynamic exchanges that exert global effect on stability of the Hsp90 dimer, while promoting client instability. The network-based rigidity analysis and emulation of thermal unfolding of the Cdk4-cyclin D complex and Hsp90-Cdc37-Cdk4 complex revealed weak spots of kinase instability that are present in the native Cdk4 structure and are targeted by the chaperone during client recruitment. Our findings suggested that this

  14. Accumulation of proteinase K-resistant prion protein (PrP) is restricted by the expression level of normal PrP in mice inoculated with a mouse-adapted strain of the Creutzfeldt-Jakob disease agent.

    OpenAIRE

    Sakaguchi, S; Katamine, S.; Shigematsu, K.; Nakatani, A; Moriuchi, R.; Nishida, N.; Kurokawa, K; Nakaoke, R; Sato, H; Jishage, K

    1995-01-01

    Creutzfeldt-Jakob disease (CJD) is a transmissible neurodegenerative disease of humans caused by an unidentified infectious agent, the prion. To determine whether there was an involvement of the host-encoded prion protein (PrPc) in CJD development and prion propagation, mice heterozygous (PrP+/-) or homozygous (PrP-/-) for a disrupted PrP gene were established and inoculated with the mouse-adapted CJD agent. In keeping with findings of previous studies using other lines of PrP-less mice inocu...

  15. Chaperone Use by Residents During Pelvic, Breast, Testicular, and Rectal Exams

    OpenAIRE

    Ehrenthal, Deborah B; Farber, Neil J.; Collier, Virginia U; Aboff, Brian M

    2000-01-01

    We designed a questionnaire survey to study internal medicine residents' plans to use a chaperone during the pelvic, breast, rectal, and testicular examinations. We found chaperone use by male and female residents differed markedly, and neither group planned to use chaperones universally. When examining female patients, male residents overall were very likely to use a chaperone during a pelvic exam, but less likely for the breast exam and rectal exam. For the female resident, there was a sign...

  16. Activated platelet-rich plasma improves adipose-derived stem cell transplantation efficiency in injured articular cartilage

    Science.gov (United States)

    2013-01-01

    Introduction Adipose-derived stem cells (ADSCs) have been isolated, expanded, and applied in the treatment of many diseases. ADSCs have also been used to treat injured articular cartilage. However, there is controversy regarding the treatment efficiency. We considered that ADSC transplantation with activated platelet-rich plasma (PRP) may improve injured articular cartilage compared with that of ADSC transplantation alone. In this study, we determined the role of PRP in ADSC transplantation to improve the treatment efficiency. Methods ADSCs were isolated and expanded from human adipose tissue. PRP was collected and activated from human peripheral blood. The effects of PRP were evaluated in vitro and in ADSC transplantation in vivo. In vitro, the effects of PRP on ADSC proliferation, differentiation into chondrogenic cells, and inhibition of angiogenic factors were investigated at three concentrations of PRP (10%, 15% and 20%). In vivo, ADSCs pretreated with or without PRP were transplanted into murine models of injured articular cartilage. Results PRP promoted ADSC proliferation and differentiation into chondrogenic cells that strongly expressed collagen II, Sox9 and aggrecan. Moreover, PRP inhibited expression of the angiogenic factor vascular endothelial growth factor. As a result, PRP-pretreated ADSCs improved healing of injured articular cartilage in murine models compared with that of untreated ADSCs. Conclusion Pretreatment of ADSCs with PRP is a simple method to efficiently apply ADSCs in cartilage regeneration. This study provides an important step toward the use of autologous ADSCs in the treatment of injured articular cartilage. PMID:23915433

  17. Presence of chaperones during pelvic examinations in southeast ...

    African Journals Online (AJOL)

    2012-12-12

    Dec 12, 2012 ... Nigerian Journal of Clinical Practice • Oct-Dec 2013 • Vol 16 • Issue 4. Abstract. Objectives: To assess the opinions, attitude, and preferences of Nigerian women to the presence of chaperones during pelvic examinations. Materials and Methods: A cross-sectional survey of first time gynecology clinic ...

  18. Treatment of Fabry's Disease with the Pharmacologic Chaperone Migalastat

    DEFF Research Database (Denmark)

    Germain, Dominique P; Hughes, Derralynn A; Nicholls, Kathleen

    2016-01-01

    BACKGROUND: Fabry's disease, an X-linked disorder of lysosomal α-galactosidase deficiency, leads to substrate accumulation in multiple organs. Migalastat, an oral pharmacologic chaperone, stabilizes specific mutant forms of α-galactosidase, increasing enzyme trafficking to lysosomes. METHODS: The...

  19. Chaperone-assisted translocation of flexible polymers in three dimensions

    Science.gov (United States)

    Suhonen, P. M.; Linna, R. P.

    2016-01-01

    Polymer translocation through a nanometer-scale pore assisted by chaperones binding to the polymer is a process encountered in vivo for proteins. Studying the relevant models by computer simulations is computationally demanding. Accordingly, previous studies are either for stiff polymers in three dimensions or flexible polymers in two dimensions. Here, we study chaperone-assisted translocation of flexible polymers in three dimensions using Langevin dynamics. We show that differences in binding mechanisms, more specifically, whether a chaperone can bind to a single site or multiple sites on the polymer, lead to substantial differences in translocation dynamics in three dimensions. We show that the single-binding mode leads to dynamics that is very much like that in the constant-force driven translocation and accordingly mainly determined by tension propagation on the cis side. We obtain β ≈1.26 for the exponent for the scaling of the translocation time with polymer length. This fairly low value can be explained by the additional friction due to binding particles. The multiple-site binding leads to translocation the dynamics of which is mainly determined by the trans side. For this process we obtain β ≈1.36 . This value can be explained by our derivation of β =4 /3 for constant-bias translocation, where translocated polymer segments form a globule on the trans side. Our results pave the way for understanding and utilizing chaperone-assisted translocation where variations in microscopic details lead to rich variations in the emerging dynamics.

  20. The small heat shock proteins family : The long forgotten chaperones

    NARCIS (Netherlands)

    Garrido, C.; Paul, C.; Seigneuric, R.; Kampinga, H. H.

    2012-01-01

    Small heat shock proteins are a rather heterogeneous family of ATP-independent chaperones, some of which have been proven to block protein aggregation and help the cells to survive stressful conditions. Although much less studied than high molecular weight HSPs like HSP70/HSPA or HSP90/HSPC, their

  1. Is PRP useful in alveolar cleft reconstruction? Platelet-rich plasma in secondary alveoloplasty.

    Science.gov (United States)

    Luaces-Rey, Ramon; Arenaz-Búa, Jorge; Lopez-Cedrún-Cembranos, José-Luis; Herrero-Patiño, Susana; Sironvalle-Soliva, Sheyla; Iglesias-Candal, Emma; Pombo-Castro, María

    2010-07-01

    Cleft lip and palate is a congenital facial malformation with an established treatment protocol. Mixed dentition period is the best moment for correct maxillary bone defect with an alveoloplasty. The aim of this surgical procedure is to facilitate dental eruption, re-establish maxillary arch, close any oro-nasal communication, give support to nasal ala, and in some cases allow dental rehabilitation with osteointegrated implants. Twenty cleft patients who underwent secondary alveoloplasty were included. In 10 of them autogenous bone graft were used and in other 10 autogenous bone and platelet-rich plasma (PRP) obtained from autogenous blood. Bone formation was compared by digital orthopantomography made on immediate post-operatory and 3 and 6 months after the surgery. No significant differences were found between both therapeutic groups on bone regeneration. We do not find justified the use of PRP for alveoloplasty in cleft patients' treatment protocol.

  2. Tendinopathies and platelet-rich plasma (PRP): from pre-clinical experiments to therapeutic use

    Science.gov (United States)

    Kaux, Jean-François; Drion, Pierre; Croisier, Jean-Louis; Crielaard, Jean-Michel

    2015-01-01

    Objectives: The restorative properties of platelets, through the local release of growth factors, are used in various medical areas. This article reviews fundamental and clinical research relating to platelet-rich plasma applied to tendinous lesions. Materials and method: Articles in French and English, published between 1 January 2012 and 31 December 2014. dealing with PRP and tendons were searched for using the Medline and Scopus data bases. Results: Forty-seven articles were identified which addressed pre-clinical and clinical studies: 27 relating to in vitro and in vivo animal studies and 20 relating to human studies. Of these, five addressed lateral epicondylitis, two addressed rotator cuff tendinopathies, ten dealt with patellar tendinopathies and three looked at Achilles tendinopathies. Conclusions: The majority of pre-clinical studies show that PRP stimulates the tendon’s healing process. However, clinical series remain more controversial and level 1, controlled, randomised studies are still needed. PMID:26195890

  3. Tendinopathies and platelet-rich plasma (PRP: from pre-clinical experiments to therapeutic use

    Directory of Open Access Journals (Sweden)

    Kaux JF

    2015-05-01

    Full Text Available Objectives: The restorative properties of platelets, through the local release of growth factors, are used in various medical areas. This article reviews fundamental and clinical research relating to platelet-rich plasma applied to tendinous lesions. Materials and method: Articles in French and English, published between 1 January 2012 and 31 December 2014. dealing with PRP and tendons were searched for using the Medline and Scopus data bases. Results: Forty-seven articles were identified which addressed pre-clinical and clinical studies: 27 relating to in vitro and in vivo animal studies and 20 relating to human studies. Of these, five addressed lateral epicondylitis, two addressed rotator cuff tendinopathies, ten dealt with patellar tendinopathies and three looked at Achilles tendinopathies. Conclusions: The majority of pre-clinical studies show that PRP stimulates the tendon's healing process. However, clinical series remain more controversial and level 1, controlled, randomised studies are still needed.

  4. IMPACT OF NATURAL FERTILIZATION USING PRP FIX ON SOME SOIL FERTILITY INDICATORS

    Directory of Open Access Journals (Sweden)

    Ewa Możdżer

    2017-07-01

    Contents of determined macronutrients in the soil were higher in objects where slurry was applied with addition of 8 kg or 12 kg of PRP FIX per 1 m3 as compared to those with exclusively mineral fertilization or slurry. The soil after test plants harvest contained more N, Corg., P, K, Mg, Ca, S, and available forms of P, K, Mg and SO3 in relation to levels before experiment establishment. In general, more soil fertility indicators were recorded in objects treated with the slurry along with PRP FIX preparation and additional PK nutrition (series II as compared to series I. Differences in macronutrients in the soil due to the fertilization system applied were diverse, however they not always were significant.

  5. Differential Regulation of G1 CDK Complexes by the Hsp90-Cdc37 Chaperone System

    Directory of Open Access Journals (Sweden)

    Stephen T. Hallett

    2017-10-01

    Full Text Available Summary: Selective recruitment of protein kinases to the Hsp90 system is mediated by the adaptor co-chaperone Cdc37. We show that assembly of CDK4 and CDK6 into protein complexes is differentially regulated by the Cdc37-Hsp90 system. Like other Hsp90 kinase clients, binding of CDK4/6 to Cdc37 is blocked by ATP-competitive inhibitors. Cdc37-Hsp90 relinquishes CDK6 to D3- and virus-type cyclins and to INK family CDK inhibitors, whereas CDK4 is relinquished to INKs but less readily to cyclins. p21CIP1 and p27KIP1 CDK inhibitors are less potent than the INKs at displacing CDK4 and CDK6 from Cdc37. However, they cooperate with the D-type cyclins to generate CDK4/6-containing ternary complexes that are resistant to cyclin D displacement by Cdc37, suggesting a molecular mechanism to explain the assembly factor activity ascribed to CIP/KIP family members. Overall, our data reveal multiple mechanisms whereby the Hsp90 system may control formation of CDK4- and CDK6-cyclin complexes under different cellular conditions. : Hallett et al. reconstitute CDK4/6 client kinase handover from Cdc37-Hsp90 to CDK regulatory partners and propose a model for the assembly factor activity of CIP/KIP CDK inhibitors. They find that CDK4/6 inhibitors in clinical use can displace G1 CDKs from the Cdc37-Hsp90 chaperone system at submicromolar concentrations. Keywords: Cdc37, CDK, chaperone, CIP/KIP, cyclin D, Hsp90, INK, kinase, palbociclib, ribociclib

  6. Secreted protein acidic and rich in cysteine is a matrix scavenger chaperone.

    Directory of Open Access Journals (Sweden)

    Alexandre Chlenski

    Full Text Available Secreted Protein Acidic and Rich in Cysteine (SPARC is one of the major non-structural proteins of the extracellular matrix (ECM in remodeling tissues. The functional significance of SPARC is emphasized by its origin in the first multicellular organisms and its high degree of evolutionary conservation. Although SPARC has been shown to act as a critical modulator of ECM remodeling with profound effects on tissue physiology and architecture, no plausible molecular mechanism of its action has been proposed. In the present study, we demonstrate that SPARC mediates the disassembly and degradation of ECM networks by functioning as a matricellular chaperone. While it has low affinity to its targets inside the cells where the Ca(2+ concentrations are low, high extracellular concentrations of Ca(2+ activate binding to multiple ECM proteins, including collagens. We demonstrated that in vitro, this leads to the inhibition of collagen I fibrillogenesis and disassembly of pre-formed collagen I fibrils by SPARC at high Ca(2+ concentrations. In cell culture, exogenous SPARC was internalized by the fibroblast cells in a time- and concentration-dependent manner. Pulse-chase assay further revealed that internalized SPARC is quickly released outside the cell, demonstrating that SPARC shuttles between the cell and ECM. Fluorescently labeled collagen I, fibronectin, vitronectin, and laminin were co-internalized with SPARC by fibroblasts, and semi-quantitative Western blot showed that SPARC mediates internalization of collagen I. Using a novel 3-dimensional model of fluorescent ECM networks pre-deposited by live fibroblasts, we demonstrated that degradation of ECM depends on the chaperone activity of SPARC. These results indicate that SPARC may represent a new class of scavenger chaperones, which mediate ECM degradation, remodeling and repair by disassembling ECM networks and shuttling ECM proteins into the cell. Further understanding of this mechanism may provide

  7. Using PRP and human amniotic fluid combination for osteogenesis in rabbit socket preservation

    Directory of Open Access Journals (Sweden)

    Amir Hossein Moradi

    2015-01-01

    Full Text Available Introduction: Platelet-rich plasma (PRP is used as an adjunct treatment during periodontal grafting surgery because of its capability of enhancing healing process. Amniotic fluid is a rich source of growth factors and hyaluronic acid (HA and a good point to study its properties of wound healing and bone formation. The aim of this study was to evaluate the osteogenic properties of a combination of amniotic fluid and PRP in rabbit′s dental socket preservation. Materials and Methods: The study population consisted of 24 healthy male laboratory rabbits (average weight 3,125 ± 185 gr that were randomly allocated into four groups. PRP for the first group, human amniotic fluid (HAF for the second group, a combination of PRP and HAF (PRHA for the third group was used. In the fourth (control group, no biomaterial was used. In each group, half of the rabbits were sacrificed at 4 weeks following surgery and the rest were sacrificed after 8 weeks. Histological analysis of biopsies of the sockets was performed using hematoxylin and eosin (H&E staining. Data were analyzed using Statistical Package for the Social Sciences (SPSS software (version 16 and P-value <0.05 was considered significance. Results: All three experimental groups showed positive effect on bone formation in terms of area of trabecular bone and number of osteocytes and also vessel formation. Socket preservation using HAF and PRHA showed the highest impact on bone formation. Socket preservation using HAF also had the highest impact on vessel formation. Conclusion: PRHA and HAF appear to be useful for enhancing bone formation. Since there was no difference between HAF and PRHA, it seems beneficial to use HAF due to its simplicity of application.

  8. Efectividad del PRP en el tratamiento de la artrosis de rodilla: Estudio de casos

    OpenAIRE

    Fernández Valverde, Noelia; Fidalgo González, Verónica

    2016-01-01

    La artrosis es una enfermedad degenerativa de elevada prevalencia para la cual, en la actualidad, no hay tratamiento curativo. Una de las localizaciones más frecuentes es la rodilla. La utilización de infiltraciones de plasma rico en plaquetas constituye una alternativa en el tratamiento de esta patología. Objetivo: demostrar la efectividad y la seguridad de las infiltraciones con PRP en el tratamiento de pacientes con artrosis de rodilla. Resultado: este trabajo muestra una...

  9. Platelet-rich plasma (PRP) in dental and oral surgery: from the wound healing to bone regeneration

    National Research Council Canada - National Science Library

    Albanese, Antonino; Licata, Maria E; Polizzi, Bianca; Campisi, Giuseppina

    2013-01-01

    Platelet-rich plasma (PRP) is a new approach to tissue regeneration and it is becoming a valuable adjunct to promote healing in many procedures in dental and oral surgery, especially in aging patients...

  10. Efficacy of leukocyte‐ and platelet‐rich plasma gel (L‐PRP gel) in treating osteomyelitis in a rabbit model

    National Research Council Canada - National Science Library

    Li, Guang‐Yi; Yin, Ji‐Min; Ding, Hao; Jia, Wei‐Tao; Zhang, Chang‐Qing

    2013-01-01

    Leukocyte‐ and platelet‐rich plasma gel (L‐PRP gel), a new autologous product which was previously utilized in several surgical procedures to enhance tissue healing, is now increasingly used as a promising treatment method for infections...

  11. Split face comparative study of microneedling with prp versus microneedling with vitamin c in treating atrophic post acne scars: Erratum

    National Research Council Canada - National Science Library

    2015-01-01

      The article, "Split Face Comparative Study of Microneedling with PRP Versus Microneedling with Vitamin C in Treating Atrophic Post Acne Scars", which appeared in the pages 209-212 Issue 4, Vol 7...

  12. Comparing hybrid hyaluronic acid with PRP in end career athletes with degenerative cartilage lesions of the knee.

    Science.gov (United States)

    Papalia, R; Zampogna, B; Russo, F; Vasta, S; Tirindelli, M C; Nobile, C; Di Martino, A C; Vadalà, G; Denaro, V

    2016-01-01

    Cartilage lesions are very common causes of chronic knee pain in athletes. Current treatment options consist in conservative strategies, such as viscosupplementation and platelet-rich plasma injections. This randomized controlled trial aims to investigate the effect of intra-articular Hybrid Hyaluronic Acid injections compared to PRP for the treatment of cartilage lesions among athletes at the end of their career. Since March 2015, 48 professional soccer players were randomized into two groups: 24 patients received 3 injections of HHA and 23 patients received 3 intra-articular injections of PRP. All patients achieved a statistically significant clinical improvement from preoperative to postoperative time in both groups. Patients in the HHA group showed a significant superiority compared to PRP group at 3 and 6 months. Intergroup differences decrease gradually until loss of significance at 12 months follow-up. Athletes with chronic degenerative cartilage lesions of the knee responded positively both to HHA and PRP until last follow up.

  13. Sequence polymorphism of PrP exon 3 gene in Istrian and crossbred sheep

    Directory of Open Access Journals (Sweden)

    Ino Curik

    2010-01-01

    Full Text Available Polymorphisms in sheep PrP (prion protein gene are known for scrapie susceptibility. We sequenced part of PrP exon 3 gene in 92 autochthonous Istrian (IS and 38 crossbred sheep (CBS. ARQ, ARR and AHQ alleles were predominant with frequency of 0.674 (0.526, 0.228 (0.132 and 0.082 (0.263 in IS (CBS, respectively, while VRQ (0.011 in IS and ARH (0.005 in IS and 0.079 in CBS alleles were rare. We also found non-synonymous mutations at codons 112 (M→T, 127 (G→S and 143 (H→R, and synonymous mutations at codons 231 (R and 237 (L. Additional mutations were associated only with AHQ, ARH and ARQ alleles. The polymorphism of PrP gene in IS was not critical with respect to scrapie susceptibility and with some efforts number of “favourable” genotypes can be increased.

  14. NMR structure of the mouse prion protein domain PrP(121-231).

    Science.gov (United States)

    Riek, R; Hornemann, S; Wider, G; Billeter, M; Glockshuber, R; Wüthrich, K

    1996-07-11

    The 'protein only' hypothesis states that a modified form of normal prion protein triggers infectious neurodegenerative diseases, such as bovine spongiform encephalopathy (BSE), or Creutzfeldt-Jakob disease (CJD) in humans. Prion proteins are thought to exist in two different conformations: the 'benign' PrPcform, and the infectious 'scrapie form', PrPsc. Knowledge of the three-dimensional structure of PrPc is essential for understanding the transition to PrPsc. The nuclear magnetic resonance (NMR) structure of the autonomously folding PrP domain comprising residues 121-231 (ref. 6) contains a two-stranded antiparallel beta-sheet and three alpha-helices. This domain contains most of the point-mutation sites that have been linked, in human PrP, to the occurrence of familial prion diseases. The NMR structure shows that these mutations occur within, or directly adjacent to, regular secondary structures. The presence of a beta-sheet in PrP(121-231) is in contrast with model predictions of an all-helical structure of PrPc (ref. 8), and may be important for the initiation of the transition from PrPc to PrPsc.

  15. Platelet-rich plasma (PRP) in dental and oral surgery: from the wound healing to bone regeneration.

    Science.gov (United States)

    Albanese, Antonino; Licata, Maria E; Polizzi, Bianca; Campisi, Giuseppina

    2013-06-13

    Platelet-rich plasma (PRP) is a new approach to tissue regeneration and it is becoming a valuable adjunct to promote healing in many procedures in dental and oral surgery, especially in aging patients. PRP derives from the centrifugation of the patient's own blood and it contains growth factors that influence wound healing, thereby playing an important role in tissue repairing mechanisms. The use of PRP in surgical practice could have beneficial outcomes, reducing bleeding and enhancing soft tissue healing and bone regeneration. Studies conducted on humans have yielded promising results regarding the application of PRP to many dental and oral surgical procedures (i.e. tooth extractions, periodontal surgery, implant surgery). The use of PRP has also been proposed in the management of bisphosphonate-related osteonecrosis of the jaw (BRONJ) with the aim of enhancing wound healing and bone maturation. The aims of this narrative review are: i) to describe the different uses of PRP in dental surgery (tooth extractions and periodontal surgery) and oral surgery (soft tissues and bone tissue surgery, implant surgery and BRONJ surgery); and ii) to discuss its efficacy, efficiency and risk/benefit ratio. This review suggests that the use of PRP in the alveolar socket after tooth extractions is certainly capable of improving soft tissue healing and positively influencing bone regeneration but the latter effect seems to decrease a few days after the extraction. PRP has produced better results in periodontal therapy in association with other materials than when it is used alone. Promising results have also been obtained in implant surgery, when PRP was used in isolation as a coating material. The combination of necrotic bone curettage and PRP application seem to be encouraging for the treatment of refractory BRONJ, as it has proven successful outcomes with minimal invasivity. Since PRP is free from potential risks for patients, not difficult to obtain and use, it can be employed

  16. Chaperones and multitasking proteins in the nucleolus: networking together for survival?

    Science.gov (United States)

    Bański, Piotr; Kodiha, Mohamed; Stochaj, Ursula

    2010-07-01

    The nucleolus has emerged as a key player that regulates cell growth, survival and the recovery from stress. Progress in proteomics made it possible to sequence the nucleolar proteome under different physiological conditions. Together with other research, this work revealed the presence of multiple chaperones and co-chaperones in the nucleolus. Molecular chaperones are components of a larger network that promotes protein homeostasis, thereby providing continuous adaptation to a changing environment. Recent studies suggest that the cellular chaperone network is divided into individual branches which orchestrate specific functions. Input from separate branches is then combined to 'fine-tune' the cellular proteostasis network. Based on the latest developments in nucleolar and chaperone biology, we speculate that a unique network comprising chaperones, co-chaperones and multitasking proteins is located in nucleoli. This network supports and regulates fundamental biological processes, including ribosome biogenesis, cell signaling, and the stress response. Copyright 2010 Elsevier Ltd. All rights reserved.

  17. The chaperone ClpX stimulates expression of Staphylococcus aureus protein A by rot dependent and independent pathways

    DEFF Research Database (Denmark)

    Jelsbak, Lotte; Ingmer, Hanne; Valihrach, Lukás

    2010-01-01

    The Clp ATPases (Hsp100) constitute a family of closely related proteins that have protein reactivating and remodelling activities typical of molecular chaperones. In Staphylococcus aureus the ClpX chaperone is essential for virulence and for transcription of spa encoding Protein A. The present...... study was undertaken to elucidate the mechanism by which ClpX stimulates expression of Protein A. For this purpose, we prepared antibodies directed against Rot, an activator of spa transcription, and demonstrated that cells devoid of ClpX contain three-fold less Rot than wild-type cells. By varying Rot...... expression from an inducible promoter we showed that expression of Protein A requires a threshold level of Rot. In the absence of ClpX the Rot content is reduced below this threshold level, hence, explaining the substantially reduced Protein A expression in the clpX mutant. Experiments addressed...

  18. At the Start of the Sarcomere: A Previously Unrecognized Role for Myosin Chaperones and Associated Proteins during Early Myofibrillogenesis

    Directory of Open Access Journals (Sweden)

    J. Layne Myhre

    2012-01-01

    Full Text Available The development of striated muscle in vertebrates requires the assembly of contractile myofibrils, consisting of highly ordered bundles of protein filaments. Myofibril formation occurs by the stepwise addition of complex proteins, a process that is mediated by a variety of molecular chaperones and quality control factors. Most notably, myosin of the thick filament requires specialized chaperone activity during late myofibrillogenesis, including that of Hsp90 and its cofactor, Unc45b. Unc45b has been proposed to act exclusively as an adaptor molecule, stabilizing interactions between Hsp90 and myosin; however, recent discoveries in zebrafish and C. elegans suggest the possibility of an earlier role for Unc45b during myofibrillogenesis. This role may involve functional control of nonmuscle myosins during the earliest stages of myogenesis, when premyofibril scaffolds are first formed from dynamic cytoskeletal actin. This paper will outline several lines of evidence that converge to build a model for Unc45b activity during early myofibrillogenesis.

  19. A prion-like domain in Hsp42 drives chaperone-facilitated aggregation of misfolded proteins.

    Science.gov (United States)

    Grousl, Tomas; Ungelenk, Sophia; Miller, Stephanie; Ho, Chi-Ting; Khokhrina, Maria; Mayer, Matthias P; Bukau, Bernd; Mogk, Axel

    2018-01-23

    Chaperones with aggregase activity promote and organize the aggregation of misfolded proteins and their deposition at specific intracellular sites. This activity represents a novel cytoprotective strategy of protein quality control systems; however, little is known about its mechanism. In yeast, the small heat shock protein Hsp42 orchestrates the stress-induced sequestration of misfolded proteins into cytosolic aggregates (CytoQ). In this study, we show that Hsp42 harbors a prion-like domain (PrLD) and a canonical intrinsically disordered domain (IDD) that act coordinately to promote and control protein aggregation. Hsp42 PrLD is essential for CytoQ formation and is bifunctional, mediating self-association as well as binding to misfolded proteins. Hsp42 IDD confines chaperone and aggregase activity and affects CytoQ numbers and stability in vivo. Hsp42 PrLD and IDD are both crucial for cellular fitness during heat stress, demonstrating the need for sequestering misfolded proteins in a regulated manner. © 2018 Grousl et al.

  20. Tratamiento de quemaduras mediante plasma rico en plaquetas (PRP: parte I

    Directory of Open Access Journals (Sweden)

    G. Rossani

    2014-06-01

    Full Text Available El objetivo del presente trabajo es determinar la eficacia clínica del plasma rico en plaquetas (PRP en las quemaduras de segundo grado. Estudiamos el tiempo requerido en la reepitelización del tejido dañado, la estancia hospitalaria asociada a la curación de las lesiones y la satisfacción del paciente. Realizamos un estudio prospectivo, observacional y longitudinal, en una muestra de 115 pacientes con quemaduras de segundo grado según la clasificación de Converse-Smith. Las lesiones fueron de menos de 48 horas de evolución, en diferentes zonas de cara y cuerpo. A todos los pacientes se les aplicó de forma ambulatoria PRP por goteo, completándose el tratamiento con la aplicación de gasas parafinadas. El estudio se realizó entre marzo de 2011 y agosto de 2013. Las quemaduras que evolucionaron mejor y de forma más rápida fueron las de cara, seguidas por las de abdomen y, por último, las de extremidades inferiores. En todas, el tiempo de epitelización fue un 30 % inferior que en quemaduras de similar extensión, profundidad y localización, en pacientes anteriormente tratados sin PRP. Los pacientes fueron atendidos ambulatoriamente cuando las lesiones lo permitieron, y si presentaban lesiones más extensas fueron hospitalizados. El tiempo de internamiento en estos casos se redujo como promedio 18 días con respecto al grupo no tratado con PRP. El tiempo de reepitelización, estancia hospitalaria y la satisfacción de los pacientes, alcanzaron significación estadística p< 0,05. En conclusión, creemos que el uso de PRP acorta el tiempo de recuperación en quemaduras de segundo grado, reduce el tiempo de hospitalización y conlleva un alto grado de satisfacción de los pacientes por los resultados obtenidos.

  1. NarJ chaperone binds on two distinct sites of the aponitrate reductase of Escherichia coli to coordinate molybdenum cofactor insertion and assembly.

    Science.gov (United States)

    Vergnes, Alexandra; Pommier, Janine; Toci, René; Blasco, Francis; Giordano, Gérard; Magalon, Axel

    2006-01-27

    Understanding when and how metal cofactor insertion occurs into a multisubunit metalloenzyme is of fundamental importance. Molybdenum cofactor insertion is a tightly controlled process that involves specific interactions between the proteins that promote cofactor delivery, enzyme-specific chaperones, and the apoenzyme. In the assembly pathway of the multisubunit molybdoenzyme, membrane-bound nitrate reductase A from Escherichia coli, a NarJ-assisted molybdenum cofactor (Moco) insertion step, must precede membrane anchoring of the apoenzyme. Here, we have shown that the NarJ chaperone interacts at two distinct binding sites of the apoenzyme, one interfering with its membrane anchoring and another one being involved in molybdenum cofactor insertion. The presence of the two NarJ-binding sites within NarG is required to ensure productive formation of active nitrate reductase. Our findings supported the view that enzyme-specific chaperones play a central role in the biogenesis of multisubunit molybdoenzymes by coordinating subunits assembly and molybdenum cofactor insertion.

  2. Broadening the functionality of a J-protein/Hsp70 molecular chaperone system.

    Directory of Open Access Journals (Sweden)

    Brenda A Schilke

    2017-10-01

    Full Text Available By binding to a multitude of polypeptide substrates, Hsp70-based molecular chaperone systems perform a range of cellular functions. All J-protein co-chaperones play the essential role, via action of their J-domains, of stimulating the ATPase activity of Hsp70, thereby stabilizing its interaction with substrate. In addition, J-proteins drive the functional diversity of Hsp70 chaperone systems through action of regions outside their J-domains. Targeting to specific locations within a cellular compartment and binding of specific substrates for delivery to Hsp70 have been identified as modes of J-protein specialization. To better understand J-protein specialization, we concentrated on Saccharomyces cerevisiae SIS1, which encodes an essential J-protein of the cytosol/nucleus. We selected suppressors that allowed cells lacking SIS1 to form colonies. Substitutions changing single residues in Ydj1, a J-protein, which, like Sis1, partners with Hsp70 Ssa1, were isolated. These gain-of-function substitutions were located at the end of the J-domain, suggesting that suppression was connected to interaction with its partner Hsp70, rather than substrate binding or subcellular localization. Reasoning that, if YDJ1 suppressors affect Ssa1 function, substitutions in Hsp70 itself might also be able to overcome the cellular requirement for Sis1, we carried out a selection for SSA1 suppressor mutations. Suppressing substitutions were isolated that altered sites in Ssa1 affecting the cycle of substrate interaction. Together, our results point to a third, additional means by which J-proteins can drive Hsp70's ability to function in a wide range of cellular processes-modulating the Hsp70-substrate interaction cycle.

  3. Broadening the functionality of a J-protein/Hsp70 molecular chaperone system.

    Science.gov (United States)

    Schilke, Brenda A; Ciesielski, Szymon J; Ziegelhoffer, Thomas; Kamiya, Erina; Tonelli, Marco; Lee, Woonghee; Cornilescu, Gabriel; Hines, Justin K; Markley, John L; Craig, Elizabeth A

    2017-10-01

    By binding to a multitude of polypeptide substrates, Hsp70-based molecular chaperone systems perform a range of cellular functions. All J-protein co-chaperones play the essential role, via action of their J-domains, of stimulating the ATPase activity of Hsp70, thereby stabilizing its interaction with substrate. In addition, J-proteins drive the functional diversity of Hsp70 chaperone systems through action of regions outside their J-domains. Targeting to specific locations within a cellular compartment and binding of specific substrates for delivery to Hsp70 have been identified as modes of J-protein specialization. To better understand J-protein specialization, we concentrated on Saccharomyces cerevisiae SIS1, which encodes an essential J-protein of the cytosol/nucleus. We selected suppressors that allowed cells lacking SIS1 to form colonies. Substitutions changing single residues in Ydj1, a J-protein, which, like Sis1, partners with Hsp70 Ssa1, were isolated. These gain-of-function substitutions were located at the end of the J-domain, suggesting that suppression was connected to interaction with its partner Hsp70, rather than substrate binding or subcellular localization. Reasoning that, if YDJ1 suppressors affect Ssa1 function, substitutions in Hsp70 itself might also be able to overcome the cellular requirement for Sis1, we carried out a selection for SSA1 suppressor mutations. Suppressing substitutions were isolated that altered sites in Ssa1 affecting the cycle of substrate interaction. Together, our results point to a third, additional means by which J-proteins can drive Hsp70's ability to function in a wide range of cellular processes-modulating the Hsp70-substrate interaction cycle.

  4. Spinal Muscular Atrophy: From Defective Chaperoning of snRNP Assembly to Neuromuscular Dysfunction

    Directory of Open Access Journals (Sweden)

    Maia Lanfranco

    2017-06-01

    Full Text Available Spinal Muscular Atrophy (SMA is a neuromuscular disorder that results from decreased levels of the survival motor neuron (SMN protein. SMN is part of a multiprotein complex that also includes Gemins 2–8 and Unrip. The SMN-Gemins complex cooperates with the protein arginine methyltransferase 5 (PRMT5 complex, whose constituents include WD45, PRMT5 and pICln. Both complexes function as molecular chaperones, interacting with and assisting in the assembly of an Sm protein core onto small nuclear RNAs (snRNAs to generate small nuclear ribonucleoproteins (snRNPs, which are the operating components of the spliceosome. Molecular and structural studies have refined our knowledge of the key events taking place within the crowded environment of cells and the numerous precautions undertaken to ensure the faithful assembly of snRNPs. Nonetheless, it remains unclear whether a loss of chaperoning in snRNP assembly, considered as a “housekeeping” activity, is responsible for the selective neuromuscular phenotype in SMA. This review thus shines light on in vivo studies that point toward disturbances in snRNP assembly and the consequential transcriptome abnormalities as the primary drivers of the progressive neuromuscular degeneration underpinning the disease. Disruption of U1 snRNP or snRNP assembly factors other than SMN induces phenotypes that mirror aspects of SMN deficiency, and splicing defects, described in numerous SMA models, can lead to a DNA damage and stress response that compromises the survival of the motor system. Restoring the correct chaperoning of snRNP assembly is therefore predicted to enhance the benefit of SMA therapeutic modalities based on augmenting SMN expression.

  5. Platelet-rich plasma exerts antinociceptive activity by a peripheral endocannabinoid-related mechanism.

    Science.gov (United States)

    Descalzi, Fiorella; Ulivi, Valentina; Cancedda, Ranieri; Piscitelli, Fabiana; Luongo, Livio; Guida, Francesca; Gatta, Luisa; Maione, Sabatino; Di Marzo, Vincenzo

    2013-10-01

    In regenerative medicine, platelet by-products containing factors physiologically involved in wound healing, have been successfully used in the form of platelet-rich plasma (PRP) for the topical therapy of various clinical conditions since it produces an improvement in tissue repair as well as analgesic effects. Measurement of endocannabinoids and related compounds in PRP revealed the presence of a significant amount of anandamide, 2-arachidonoylglycerol, palmitoylethanolamide, and oleoylethanolamide. Investigation of the activity of PRP on the keratinocyte cell line NCTC2544 in physiological and inflammatory conditions showed that, under inflammatory conditions, PRP induced in a statistically significant manner the production of these compounds by the cells suggesting that PRP might induce the production of these analgesic mediators particularly in the physiologically inflamed wounded tissue. Studies in a mouse model of acute inflammatory pain induced by formalin injection demonstrated a potent antinociceptive effect against both early and late nocifensive responses. This effect was observed following intrapaw injection of (1) total PRP; (2) lipids extracted from PRP; and (3) an endocannabinoid-enriched lipid fraction of PRP. In all conditions, antagonists of endocannabinoid CB1 and CB2 receptors, injected in the paw, abrogated the antinociceptive effects strongly suggesting for this preparation a peripheral mechanism of action. In conclusion, we showed that PRP and PRP lipid extract exert a potent antinociceptive activity linked, at least in part, to their endocannabinoids and related compound content, and to their capability of elevating the levels of these lipid mediators in cells.

  6. The chaperone like function of the nonhistone protein HMGB1

    Energy Technology Data Exchange (ETDEWEB)

    Osmanov, Taner; Ugrinova, Iva [Institute of Molecular Biology, Bulgarian Academy of Sciences (Bulgaria); Pasheva, Evdokia, E-mail: eva@bio21.bas.bg [Institute of Molecular Biology, Bulgarian Academy of Sciences (Bulgaria)

    2013-03-08

    Highlights: ► The HMGB1 protein strongly enhanced the formation of nucleosome particles. ► The target of HMGB1 action as a chaperone is the DNA not the histone octamer. ► The acetylation of HMGB1 decreases the stimulating effect of the protein. -- Abstract: Almost all essential nuclear processes as replication, repair, transcription and recombination require the chromatin template to be correctly unwound and than repackaged. The major strategy that the cell uses to overcome the nucleosome barrier is the proper removal of the histone octamer and subsequent deposition onto DNA. Important factors in this multi step phenomenon are the histone chaperones that can assemble nucleosome arrays in vitro in the absence of ATP. The nonhistone protein HMGB1 is a good candidate for a chaperone as its molecule consists of two DNA binding motives, Box’s A and B, and a long nonstructured C tail highly negatively charged. HMGB1 protein is known as a nuclear “architectural” factor for its property to bind preferentially to distorted DNA structures and was reported to kink the double helix. Our experiments show that in the classical stepwise dialysis method for nucleosome assembly the addition of HMGB1 protein stimulates more than two times the formation of middle-positioned nucleosomes. The stimulation effect persists in dialysis free experiment when the reconstitution is possible only in the presence of a chaperone. The addition of HMGB1 protein strongly enhanced the formation of a nucleosome in a dose dependant manner. Our results show that the target of HMGB1 action as a chaperone is the DNA fragment not the histone octamer. One possible explanation for the stimulating effect of HMGB1 is the “architectural” property of the protein to associate with the middle of the DNA fragment and to kink it. The acquired V shaped DNA structure is probably conformationals more favorable to wrap around the prefolded histone octamer. We tested also the role of the post

  7. Chaperone-mediated gene therapy with recombinant AAV-PPCA in a new mouse model of type I sialidosis.

    Science.gov (United States)

    Bonten, Erik J; Yogalingam, Gouri; Hu, Huimin; Gomero, Elida; van de Vlekkert, Diantha; d'Azzo, Alessandra

    2013-10-01

    The lysosomal storage disease sialidosis is caused by a primary deficiency of the sialidase N-acetyl-α-neuraminidase-1 (NEU1). Patients with type I sialidosis develop an attenuated, non-neuropathic form of the disease also named cherry red spot myoclonus syndrome, with symptoms arising during juvenile/ adult age. NEU1 requires binding to its chaperone, protective protein/cathepsin A (PPCA), for lysosomal compartmentalization, stability and catalytic activation. We have generated a new mouse model of type I sialidosis that ubiquitously expresses a NEU1 variant carrying a V54M amino acid substitution identified in an adult patient with type I sialidosis. Mutant mice developed signs of lysosomal disease after 1year of age, predominantly in the kidney, albeit low residual NEU1 activity was detected in most organs and cell types. We demonstrate that the activity of the mutant enzyme could be effectively increased in all systemic tissues by chaperone-mediated gene therapy with a liver-tropic recombinant AAV2/8 vector expressing PPCA. This resulted in clear amelioration of the disease phenotype. These results suggest that at least some of the NEU1 mutations associated with type I sialidosis may respond to PPCA-chaperone-mediated gene therapy. Published by Elsevier B.V.

  8. High dose of antibiotic colistin induces oligomerization of molecular chaperone HSP90.

    Science.gov (United States)

    Togashi, Shuntaro; Takahashi, Kyosuke; Tamura, Arisa; Toyota, Ikumi; Hatakeyama, Shiori; Komatsuda, Atsushi; Kudo, Ikuru; Sasaki Kudoh, Erina; Okamoto, Tomoya; Haga, Asami; Miyamoto, Asuka; Grave, Ewa; Sugawara, Taku; Shimizu, Hiroaki; Itoh, Hideaki

    2017-07-01

    Colistin is an antimicrobial cationic peptide that belongs to the polymyxin family. Colistin was clinically used for the treatment of gram-negative infections but fell out of favour because of its significant side effects including neurotoxicity and nephrotoxicity. More recently, colistin has been regarded as one of the important options for nosocomial infections caused by multidrug resistant bacteria. Mechanisms of both the side effect onset of the drug and the side effect reduction are yet to be elucidated. In this study, we identified the specific binding protein of colistin using an affinity column chromatography. Colistin binds to the molecular chaperone HSP90. Although colistin slightly suppressed the chaperone activity of HSP90, there are no effects on the ATPase activity for a low concentration of colistin. Interestingly, colistin-induced aggregation of HSP90 via the N-domain. As for the cell viability of the SHSY5Y cell, the cell viability decreased to approximately 80% by the colistin 300 μM. However, the cell viability recovered to approximately 100% by adding ATP dosage. The same result was obtained by dot blot assay using anti-HSP90 antibody. Our results may help to understand the side effect mechanism of colistin. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  9. Chemical Chaperones Reduce ER Stress and Restore Glucose Homeostasis in a Mouse Model of Type 2 Diabetes

    Science.gov (United States)

    Özcan, Umut; Yilmaz, Erkan; Özcan, Lale; Furuhashi, Masato; Vaillancourt, Eric; Smith, Ross O.; Görgün, Cem Z.; Hotamisligil, Gökhan S.

    2006-08-01

    Endoplasmic reticulum (ER) stress is a key link between obesity, insulin resistance, and type 2 diabetes. Here, we provide evidence that this mechanistic link can be exploited for therapeutic purposes with orally active chemical chaperones. 4-Phenyl butyric acid and taurine-conjugated ursodeoxycholic acid alleviated ER stress in cells and whole animals. Treatment of obese and diabetic mice with these compounds resulted in normalization of hyperglycemia, restoration of systemic insulin sensitivity, resolution of fatty liver disease, and enhancement of insulin action in liver, muscle, and adipose tissues. Our results demonstrate that chemical chaperones enhance the adaptive capacity of the ER and act as potent antidiabetic modalities with potential application in the treatment of type 2 diabetes.

  10. Metal chaperones: a holistic approach to the treatment of AD

    Directory of Open Access Journals (Sweden)

    Paul Anthony Adlard

    2012-03-01

    Full Text Available As the burden of proof for the role of metal ion dysregulation in the pathogenesis of multiple CNS disorders grows, it has become important to more precisely identify and differentiate the biological effects of various pharmacological modulators of metal ion homeostasis. This is particularly evident in disorders such as Alzheimer’s disease, where the use of metal chaperones (that transport metals, as opposed to chelators (which exclude metals from biological interactions, may prove to be the first truly disease modifying approach for this condition. The purpose of this mini-review is to highlight the emerging notion that metal chaperones, such as PBT2 (Prana Biotechnology, modulate a variety of critical pathways affecting key aspects of the AD cascade to provide a more holistic approach to the treatment of this disease.

  11. Chaperone use during intimate examinations in primary care: postal survey of family physicians

    Directory of Open Access Journals (Sweden)

    Upshur Ross EG

    2005-12-01

    Full Text Available Abstract Background Physicians have long been advised to have a third party present during certain parts of a physical examination; however, little is known about the frequency of chaperone use for those specific intimate examinations regularly performed in primary care. We aimed to determine the frequency of chaperone use among family physicians across a variety of intimate physical examinations for both male and female patients, and also to identify the factors associated with chaperone use. Methods Questionnaires were mailed to a randomly selected sample of 500 Ontario members of the College of Family Physicians of Canada. Participants were asked about their use of chaperones when performing a variety of intimate examinations, namely female pelvic, breast, and rectal exams and male genital and rectal exams. Results 276 of 500 were returned (56%, of which 257 were useable. Chaperones were more commonly used with female patients than with males (t = 9.09 [df = 249], p Conclusion Clinical practice concerning the use of chaperones during intimate exams continues to be discordant with the recommendations of medical associations and medico-legal societies. Chaperones are used by only a minority of Ontario family physicians. Chaperone use is higher for examinations of female patients than of male patients and is highest for female pelvic exams. The availability of a nurse in the clinic to act as a chaperone is associated with more frequent use of chaperones.

  12. Cloning and molecular characterization of a copper chaperone gene ...

    African Journals Online (AJOL)

    The cDNA encoding a copper chaperone, designated as HbCCH1, was isolated from Hevea brasiliensis. HbCC1 was 589 bp long containing a 261 bp open reading frame encoding a putative protein of 86 amino acids, flanked by a 103 bp 5'UTR and a 225 bp 3'UTR. The predicted molecular mass of HbCCH1 was 9.2 kDa, ...

  13. PfClpC Is an Essential Clp Chaperone Required for Plastid Integrity and Clp Protease Stability in Plasmodium falciparum.

    Science.gov (United States)

    Florentin, Anat; Cobb, David W; Fishburn, Jillian D; Cipriano, Michael J; Kim, Paul S; Fierro, Manuel A; Striepen, Boris; Muralidharan, Vasant

    2017-11-14

    The deadly malaria parasite Plasmodium falciparum contains a nonphotosynthetic plastid, known as the apicoplast, that functions to produce essential metabolites, and drugs that target the apicoplast are clinically effective. Several prokaryotic caseinolytic protease (Clp) genes have been identified in the Plasmodium genome. Using phylogenetic analysis, we focused on the Clp members that may form a regulated proteolytic complex in the apicoplast. We genetically targeted members of this complex and generated conditional mutants of the apicoplast-localized PfClpC chaperone and PfClpP protease. Conditional inhibition of the PfClpC chaperone resulted in growth arrest and apicoplast loss and was rescued by addition of the essential apicoplast-derived metabolite IPP. Using a double-conditional mutant parasite line, we discovered that the chaperone activity is required to stabilize the mature protease, revealing functional interactions. These data demonstrate the essential function of PfClpC in maintaining apicoplast integrity and its role in regulating the proteolytic activity of the Clp complex. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  14. PfClpC Is an Essential Clp Chaperone Required for Plastid Integrity and Clp Protease Stability in Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Anat Florentin

    2017-11-01

    Full Text Available The deadly malaria parasite Plasmodium falciparum contains a nonphotosynthetic plastid, known as the apicoplast, that functions to produce essential metabolites, and drugs that target the apicoplast are clinically effective. Several prokaryotic caseinolytic protease (Clp genes have been identified in the Plasmodium genome. Using phylogenetic analysis, we focused on the Clp members that may form a regulated proteolytic complex in the apicoplast. We genetically targeted members of this complex and generated conditional mutants of the apicoplast-localized PfClpC chaperone and PfClpP protease. Conditional inhibition of the PfClpC chaperone resulted in growth arrest and apicoplast loss and was rescued by addition of the essential apicoplast-derived metabolite IPP. Using a double-conditional mutant parasite line, we discovered that the chaperone activity is required to stabilize the mature protease, revealing functional interactions. These data demonstrate the essential function of PfClpC in maintaining apicoplast integrity and its role in regulating the proteolytic activity of the Clp complex.

  15. Oxidative stress and expression of chaperones in aging mollusks.

    Science.gov (United States)

    Ivanina, Anna V; Sokolova, Inna M; Sukhotin, Alexey A

    2008-05-01

    The mechanisms of aging are not well understood in animals with continuous growth such as fish, reptiles, amphibians and numerous invertebrates, including mollusks. We studied the effects of age on oxidative stress, cellular defense mechanisms (including two major antioxidant enzymes, superoxide dismutase (SOD) and catalase), and molecular chaperones in two mollusks--eastern oysters Crassostrea virginica and hard clams Mercenaria mercenaria. In order to detect the age-related changes in these parameters, correction for the effects of size was performed where appropriate to account for growth-related dilution. Fluorescent age pigments accumulated with age in both species. Protein carbonyls did not change with age or size indicating that they are not a good marker of aging in mollusks possibly due to the fast turnover and degradation of oxidized proteins in growing tissues. SOD did not show a compensatory increase with aging in either species, while catalase significantly decreased with age. Mitochondrial heat shock protein (HSP60) decreased with age in mollusks suggesting an age-related decline in mitochondrial chaperone protection. In contrast, changes in cytosolic chaperones were species-specific. HSP70 increased and HSP90 declined with age in clams, whereas in oysters HSP70 expression did not change, and HSP90 increased with aging.

  16. ATP-dependent chromatin remodeling by Cockayne syndrome protein B and NAP1-like histone chaperones is required for efficient transcription-coupled DNA repair.

    Science.gov (United States)

    Cho, Iltaeg; Tsai, Pei-Fang; Lake, Robert J; Basheer, Asjad; Fan, Hua-Ying

    2013-04-01

    The Cockayne syndrome complementation group B (CSB) protein is essential for transcription-coupled DNA repair, and mutations in CSB are associated with Cockayne syndrome--a devastating disease with complex clinical features, including the appearance of premature aging, sun sensitivity, and numerous neurological and developmental defects. CSB belongs to the SWI2/SNF2 ATP-dependent chromatin remodeler family, but the extent to which CSB remodels chromatin and whether this activity is utilized in DNA repair is unknown. Here, we show that CSB repositions nucleosomes in an ATP-dependent manner in vitro and that this activity is greatly enhanced by the NAP1-like histone chaperones, which we identify as new CSB-binding partners. By mapping functional domains and analyzing CSB derivatives, we demonstrate that chromatin remodeling by the combined activities of CSB and the NAP1-like chaperones is required for efficient transcription-coupled DNA repair. Moreover, we show that chromatin remodeling and repair protein recruitment mediated by CSB are separable activities. The collaboration that we observed between CSB and the NAP1-like histone chaperones adds a new dimension to our understanding of the ways in which ATP-dependent chromatin remodelers and histone chaperones can regulate chromatin structure. Taken together, the results of this study offer new insights into the functions of chromatin remodeling by CSB in transcription-coupled DNA repair as well as the underlying mechanisms of Cockayne syndrome.

  17. ATP-dependent chromatin remodeling by Cockayne syndrome protein B and NAP1-like histone chaperones is required for efficient transcription-coupled DNA repair.

    Directory of Open Access Journals (Sweden)

    Iltaeg Cho

    2013-04-01

    Full Text Available The Cockayne syndrome complementation group B (CSB protein is essential for transcription-coupled DNA repair, and mutations in CSB are associated with Cockayne syndrome--a devastating disease with complex clinical features, including the appearance of premature aging, sun sensitivity, and numerous neurological and developmental defects. CSB belongs to the SWI2/SNF2 ATP-dependent chromatin remodeler family, but the extent to which CSB remodels chromatin and whether this activity is utilized in DNA repair is unknown. Here, we show that CSB repositions nucleosomes in an ATP-dependent manner in vitro and that this activity is greatly enhanced by the NAP1-like histone chaperones, which we identify as new CSB-binding partners. By mapping functional domains and analyzing CSB derivatives, we demonstrate that chromatin remodeling by the combined activities of CSB and the NAP1-like chaperones is required for efficient transcription-coupled DNA repair. Moreover, we show that chromatin remodeling and repair protein recruitment mediated by CSB are separable activities. The collaboration that we observed between CSB and the NAP1-like histone chaperones adds a new dimension to our understanding of the ways in which ATP-dependent chromatin remodelers and histone chaperones can regulate chromatin structure. Taken together, the results of this study offer new insights into the functions of chromatin remodeling by CSB in transcription-coupled DNA repair as well as the underlying mechanisms of Cockayne syndrome.

  18. The genes coding for the hsp70(dnaK) molecular chaperone machine occur in the moderate thermophilic archaeon Methanosarcina thermophila TM-1

    DEFF Research Database (Denmark)

    Hofman-Bang, H Jacob Peider; Lange, Marianne; Ahring, Birgitte Kiær

    1999-01-01

    of response by hsp70(dnaK), and a similar response by trkA. The data suggest that the moderate thermophile TM-1 has an active Hsp70(DnaK)-chaperone machine in contrast to hyperthermophilic archaea, and that trkA is a stress gene, inasmuch as it responds like classic heat-shock genes to stressors that induce...

  19. Split face comparative study of microneedling with PRP versus microneedling with vitamin C in treating atrophic post acne scars

    Directory of Open Access Journals (Sweden)

    Simran Chawla

    2014-01-01

    Full Text Available Introduction: Acne scars are largely preventable complications of acne. 95% of the scars occur over the face thus impacting the quality of life. Correction of scars is the priority for acne patients. Materials and Methods: Thirty patients with post acne atrophic facial scars attending the OPD during the period from April to October 2013 were offered four sittings of microneedling with PRP on one side and microneedling with vitamin C on other side of the face at an interval of 1 month. Results: Twenty-seven out of the total 30 patients completed the treatment schedule. Two patients were lost to follow up and one dropped out of the study due to severe PIH. Mean age of the patients was 27.5 years. Out of 30 patients, 23 achieved reduction in scarring by one or two grades. Excellent response was seen in five (18.5% patients with platelet-rich plasma (PRP as compared to two (7% patients who received treatment with vitamin C according to physician′s assessment. As far as up gradation by 1 score is considered, i.e., good response, it was similar in both cases. Vitamin C did not prove to be as efficacious as PRP since 10 (37% patients had poor response in vitamin C-treated area compared to only 6 (22.2% patients who underwent PRP therapy, but vitamin C proved to be efficacious in dealing with post inflammatory hyper-pigmentation secondary to acne. Patients were more satisfied with PRP as compared to vitamin C. The results were evaluated and statistical analysis was done using SPSS 16.0.2. Conclusions: Overall results were better with microneedling and PRP. Vitamin C combined with microneedling also showed improvement with respect to firmness and smoothness of skin; as well as post inflammatory hyper-pigmentation. Microneedling combined with PRP proved to be good in treating boxcar and rolling scars but had limited efficacy in dealing with ice pick scars.

  20. The Role of Histidine-Proline-Rich Glycoprotein as Zinc Chaperone for Skeletal Muscle AMP Deaminase

    Directory of Open Access Journals (Sweden)

    Maria Ranieri-Raggi

    2014-05-01

    Full Text Available Metallochaperones function as intracellular shuttles for metal ions. At present, no evidence for the existence of any eukaryotic zinc-chaperone has been provided although metallochaperones could be critical for the physiological functions of Zn2+ metalloenzymes. We propose that the complex formed in skeletal muscle by the Zn2+ metalloenzyme AMP deaminase (AMPD and the metal binding protein histidine-proline-rich glycoprotein (HPRG acts in this manner. HPRG is a major plasma protein. Recent investigations have reported that skeletal muscle cells do not synthesize HPRG but instead actively internalize plasma HPRG. X-ray absorption spectroscopy (XAS performed on fresh preparations of rabbit skeletal muscle AMPD provided evidence for a dinuclear zinc site in the enzyme compatible with a (μ-aqua(μ-carboxylatodizinc(II core with two histidine residues at each metal site. XAS on HPRG isolated from the AMPD complex showed that zinc is bound to the protein in a dinuclear cluster where each Zn2+ ion is coordinated by three histidine and one heavier ligand, likely sulfur from cysteine. We describe the existence in mammalian HPRG of a specific zinc binding site distinct from the His-Pro-rich region. The participation of HPRG in the assembly and maintenance of skeletal muscle AMPD by acting as a zinc chaperone is also demonstrated.

  1. Phosphorylation-mediated control of histone chaperone ASF1 levels by Tousled-like kinases.

    Directory of Open Access Journals (Sweden)

    Maxim Pilyugin

    Full Text Available Histone chaperones are at the hub of a diverse interaction networks integrating a plethora of chromatin modifying activities. Histone H3/H4 chaperone ASF1 is a target for cell-cycle regulated Tousled-like kinases (TLKs and both proteins cooperate during chromatin replication. However, the precise role of post-translational modification of ASF1 remained unclear. Here, we identify the TLK phosphorylation sites for both Drosophila and human ASF1 proteins. Loss of TLK-mediated phosphorylation triggers hASF1a and dASF1 degradation by proteasome-dependent and independent mechanisms respectively. Consistent with this notion, introduction of phosphorylation-mimicking mutants inhibits hASF1a and dASF1 degradation. Human hASF1b is also targeted for proteasome-dependent degradation, but its stability is not affected by phosphorylation indicating that other mechanisms are likely to be involved in control of hASF1b levels. Together, these results suggest that ASF1 cellular levels are tightly controlled by distinct pathways and provide a molecular mechanism for post-translational regulation of dASF1 and hASF1a by TLK kinases.

  2. Localization of MRP-1 to the outer mitochondrial membrane by the chaperone protein HSP90β.

    Science.gov (United States)

    Roundhill, Elizabeth; Turnbull, Doug; Burchill, Susan

    2016-05-01

    Overexpression of plasma membrane multidrug resistance-associated protein 1 (MRP-1) in Ewing's sarcoma (ES) predicts poor outcome. MRP-1 is also expressed in mitochondria, and we have examined the submitochondrial localization of MRP-1 and investigated the mechanism of MRP-1 transport and role of this organelle in the response to doxorubicin. The mitochondrial localization of MRP-1 was examined in ES cell lines by differential centrifugation and membrane solubilization by digitonin. Whether MRP-1 is chaperoned by heat shock proteins (HSPs) was investigated by immunoprecipitation, immunofluorescence microscopy, and HSP knockout using small hairpin RNA and inhibitors (apoptozole, 17-AAG, and NVPAUY). The effect of disrupting mitochondrial MRP-1-dependent efflux activity on the cytotoxic effect of doxorubicin was investigated by counting viable cell number. Mitochondrial MRP-1 is glycosylated and localized to the outer mitochondrial membrane, where it is coexpressed with HSP90. MRP-1 binds to both HSP90 and HSP70, although only inhibition of HSP90β decreases expression of MRP-1 in the mitochondria. Disruption of mitochondrial MRP-1-dependent efflux significantly increases the cytotoxic effect of doxorubicin (combination index, MRP-1 is expressed in the outer mitochondrial membrane and is a client protein of HSP90β, where it may play a role in the doxorubicin-induced resistance of ES.-Roundhill, E., Turnbull, D., Burchill, S. Localization of MRP-1 to the outer mitochondrial membrane by the chaperone protein HSP90β. © FASEB.

  3. Transporters, chaperones, and P-type ATPases controlling grapevine copper homeostasis.

    Science.gov (United States)

    Leng, Xiangpeng; Mu, Qian; Wang, Xiaomin; Li, Xiaopeng; Zhu, Xudong; Shangguan, Lingfei; Fang, Jinggui

    2015-11-01

    With more copper and copper-containing compounds used as bactericides and fungicides in viticulture, copper homeostasis in grapevine (Vitis) has become one of the serious environmental crises with great risk. To better understand the regulation of Cu homeostasis in grapevine, grapevine seedlings cultured in vitro with different levels of Cu were utilized to investigate the tolerance mechanisms of grapevine responding to copper availability at physiological and molecular levels. The results indicated that Cu contents in roots and leaves arose with increasing levels of Cu application. With copper concentration increasing, malondialdehyde (MDA) content increased in roots and leaves and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased to protect the plant itself from damage. The expression patterns of 19 genes, encoding transporters, chaperones, and P-type ATPases involved in copper homeostasis in root and leaf of grapevine seedling under various levels of Cu(2+) were further analyzed. The expression patterns indicated that CTr1, CTr2, and CTr8 transporters were significantly upregulated in response both to Cu excess and deficiency. ZIP2 was downregulated in response to Cu excess and upregulated under Cu-deficient conditions, while ZIP4 had an opposite expression pattern under similar conditions. The expression of chaperones and P-type ATPases in response to Cu availability in grapevine were also briefly studied.

  4. Wound Healing Activity of a New Formulation from Platelet Lysate

    Directory of Open Access Journals (Sweden)

    Akram Jamshidzadeh

    2016-03-01

    Full Text Available Platelet-rich plasma (PRP is an attractive preparation in regenerative medicine due to its potential role in the healing process in different experimental models. This study was designed to investigate the wound healing activity of a new formulation of PRP. Different gel-based formulations of PRP were prepared. Open excision wounds were made on the back of male Sprague-Dawley rats, and PRP gel was administered topically once daily until the wounds healed completely (12 days. The results revealed that the tested PRP formulation significantly accelerated the wound healing process by increasing the wound contraction, tissue granulization, vascularization, and collagen regeneration. Interestingly, this study showed that there were no significant differences between the PRP and its gel-based formulation in all the above mentioned parameters. Although this investigation showed that PRP formulation had significant wound healing effects, the PRP gel-based formulation also had significant wound healing properties. This might indicate the wound healing properties of the PRP gel ingredients in the current investigation.

  5. The Hsp70/Hsp90 Chaperone Machinery in Neurodegenerative Diseases

    Science.gov (United States)

    Lackie, Rachel E.; Maciejewski, Andrzej; Ostapchenko, Valeriy G.; Marques-Lopes, Jose; Choy, Wing-Yiu; Duennwald, Martin L.; Prado, Vania F.; Prado, Marco A. M.

    2017-01-01

    The accumulation of misfolded proteins in the human brain is one of the critical features of many neurodegenerative diseases, including Alzheimer's disease (AD). Assembles of beta-amyloid (Aβ) peptide—either soluble (oligomers) or insoluble (plaques) and of tau protein, which form neurofibrillary tangles, are the major hallmarks of AD. Chaperones and co-chaperones regulate protein folding and client maturation, but they also target misfolded or aggregated proteins for refolding or for degradation, mostly by the proteasome. They form an important line of defense against misfolded proteins and are part of the cellular quality control system. The heat shock protein (Hsp) family, particularly Hsp70 and Hsp90, plays a major part in this process and it is well-known to regulate protein misfolding in a variety of diseases, including tau levels and toxicity in AD. However, the role of Hsp90 in regulating protein misfolding is not yet fully understood. For example, knockdown of Hsp90 and its co-chaperones in a Caenorhabditis elegans model of Aβ misfolding leads to increased toxicity. On the other hand, the use of Hsp90 inhibitors in AD mouse models reduces Aβ toxicity, and normalizes synaptic function. Stress-inducible phosphoprotein 1 (STI1), an intracellular co-chaperone, mediates the transfer of clients from Hsp70 to Hsp90. Importantly, STI1 has been shown to regulate aggregation of amyloid-like proteins in yeast. In addition to its intracellular function, STI1 can be secreted by diverse cell types, including astrocytes and microglia and function as a neurotrophic ligand by triggering signaling via the cellular prion protein (PrPC). Extracellular STI1 can prevent Aβ toxic signaling by (i) interfering with Aβ binding to PrPC and (ii) triggering pro-survival signaling cascades. Interestingly, decreased levels of STI1 in C. elegans can also increase toxicity in an amyloid model. In this review, we will discuss the role of intracellular and extracellular STI1 and the

  6. The Hsp70/Hsp90 Chaperone Machinery in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Rachel E. Lackie

    2017-05-01

    Full Text Available The accumulation of misfolded proteins in the human brain is one of the critical features of many neurodegenerative diseases, including Alzheimer's disease (AD. Assembles of beta-amyloid (Aβ peptide—either soluble (oligomers or insoluble (plaques and of tau protein, which form neurofibrillary tangles, are the major hallmarks of AD. Chaperones and co-chaperones regulate protein folding and client maturation, but they also target misfolded or aggregated proteins for refolding or for degradation, mostly by the proteasome. They form an important line of defense against misfolded proteins and are part of the cellular quality control system. The heat shock protein (Hsp family, particularly Hsp70 and Hsp90, plays a major part in this process and it is well-known to regulate protein misfolding in a variety of diseases, including tau levels and toxicity in AD. However, the role of Hsp90 in regulating protein misfolding is not yet fully understood. For example, knockdown of Hsp90 and its co-chaperones in a Caenorhabditis elegans model of Aβ misfolding leads to increased toxicity. On the other hand, the use of Hsp90 inhibitors in AD mouse models reduces Aβ toxicity, and normalizes synaptic function. Stress-inducible phosphoprotein 1 (STI1, an intracellular co-chaperone, mediates the transfer of clients from Hsp70 to Hsp90. Importantly, STI1 has been shown to regulate aggregation of amyloid-like proteins in yeast. In addition to its intracellular function, STI1 can be secreted by diverse cell types, including astrocytes and microglia and function as a neurotrophic ligand by triggering signaling via the cellular prion protein (PrPC. Extracellular STI1 can prevent Aβ toxic signaling by (i interfering with Aβ binding to PrPC and (ii triggering pro-survival signaling cascades. Interestingly, decreased levels of STI1 in C. elegans can also increase toxicity in an amyloid model. In this review, we will discuss the role of intracellular and extracellular

  7. Differential effect of platelet-rich plasma fractions on β1-integrin signaling, collagen biosynthesis, and prolidase activity in human skin fibroblasts

    Directory of Open Access Journals (Sweden)

    Guszczyn T

    2017-06-01

    Full Text Available Tomasz Guszczyn,1 Arkadiusz Surażyński,2 Ilona Zaręba,2 Edyta Rysiak,2 Janusz Popko,1 Jerzy Pałka2 1Department of Pediatric Orthopedics and Traumatology, 2Department of Medicinal Chemistry, Medical University of Białystok, Białystok, Poland Abstract: The study was conducted to evaluate the effects of platelet-rich plasma (PRP, supernatant of PRP (SPRP obtained by centrifugation, and supernatant of activated PRP (SActi-PRP obtained by Ca2+ solution-treated PRP on collagen biosynthesis, prolidase activity, and β1-integrin signaling in cultured human skin fibroblasts. Incubation of fibroblasts with 5% PRP for 24 h contributed to ~5-fold increase in collagen biosynthesis compared to the control. In the cells treated with 5% of SPRP or SActi-PRP, collagen biosynthesis showed a 3-fold increase of the control. PRP, SPRP, and SActi-PRP stimulated prolidase activity similar to collagen biosynthesis. Collagen biosynthesis and prolidase activity are regulated by β1-integrin receptor signaling. Incubation of fibroblasts with PRP for 24 h contributed to a dose-dependent increase in the expression of β1-integrin receptor, while SActi-PRP increased the process to a much lower extent. SPRP had no effect on the β1-integrin receptor expression. All the studied fractions of blood increased the expression of FAK as well as the expression of phosphorylated MAP-kinases. However, PRP was found to be the most effective stimulator of expression of these particular kinases. These studies suggest that a complex of factors, including growth factors, adhesion molecules, and prolidase contained in PRP, all evoke growth and collagen-promoting activities in human dermal fibroblasts. Keywords: fibroblasts, FAK, MAPK

  8. Tratamiento de quemaduras mediante plasma rico en plaquetas (PRP): parte I

    OpenAIRE

    G. Rossani; I. Hernández; J.M. Alcolea; R. Castro-Sierra; W. Pérez-Soto; M.A. Trelles

    2014-01-01

    El objetivo del presente trabajo es determinar la eficacia clínica del plasma rico en plaquetas (PRP) en las quemaduras de segundo grado. Estudiamos el tiempo requerido en la reepitelización del tejido dañado, la estancia hospitalaria asociada a la curación de las lesiones y la satisfacción del paciente. Realizamos un estudio prospectivo, observacional y longitudinal, en una muestra de 115 pacientes con quemaduras de segundo grado según la clasificación de Converse-Smith. Las lesiones fueron ...

  9. Beneficios del adhesivo autólogo de fibrina y PRP en ritidectomía

    OpenAIRE

    I. Hernández; G. Rossani; R. Castro-Sierra

    2015-01-01

    Determinamos la eficacia clínica del adhesivo autólogo de fibrina y la fracción de sangre rica en plaquetas (PRP) en la disminución de complicaciones en ritidectomía. Se intervino con igual técnica ambas hemicaras, pero solo una, aleatoriamente, recibió tratamiento con hemoderivados. Estudiamos comparativamente la evolución postquirúrgica de una hemicara frente a otra: tiempo de recuperación a corto, medio y largo plazo; incidencia de hematomas, seromas, epidermolisis, necrosis y equimosis; y...

  10. Truncated forms of the prion protein PrP demonstrate the need for complexity in prion structure

    Energy Technology Data Exchange (ETDEWEB)

    Wan, William; Stöhr, Jan; Kendall, Amy; Stubbs, Gerald

    2015-09-01

    Self-propagation of aberrant protein folds is the defining characteristic of prions. Knowing the structural basis of self-propagation is essential to understanding prions and their related diseases. Prion rods are amyloid fibrils, but not all amyloids are prions. Prions have been remarkably intractable to structural studies, so many investigators have preferred to work with peptide fragments, particularly in the case of the mammalian prion protein PrP. We compared the structures of a number of fragments of PrP by X-ray fiber diffraction, and found that although all of the peptides adopted amyloid conformations, only the larger fragments adopted conformations that modeled the complexity of self-propagating prions, and even these fragments did not always adopt the PrP structure. It appears that the relatively complex structure of the prion form of PrP is not accessible to short model peptides, and that self-propagation may be tied to a level of structural complexity unobtainable in simple model systems. The larger fragments of PrP, however, are useful to illustrate the phenomenon of deformed templating (heterogeneous seeding), which has important biological consequences.

  11. The fate of PrP GPI-anchor signal peptide is modulated by P238S pathogenic mutation.

    Science.gov (United States)

    Guizzunti, Gianni; Zurzolo, Chiara

    2014-01-01

    Glycosylphosphatidylinositol (GPI)-anchored proteins are localized to the plasma membrane via a C-terminally linked GPI anchor. The GPI anchor is added concomitantly to the cleavage of the carboxy-terminal GPI-anchor signal sequence, thereby causing the release of a C-terminal hydrophobic peptide, whose fate has not yet been investigated. Here we followed the fate of the GPI-attachment signal of the prion protein (PrP), a protein implicated in various types of transmissible neurodegenerative spongiform encephalopathies (TSE). The PrP GPI-anchor signal sequence shows a remarkable and unusual degree of conservation across the species and contains two point mutations (M232R/T and P238S) that are responsible for genetic forms of prion disorders. We show that the PrP GPI-anchor signal peptide (SP), but not the one from an unrelated GPI-anchored protein (folate receptor), undergoes degradation via the proteasome. Moreover, the P238S point mutation partially protects the PrP GPI-anchor SP from degradation. Our data provide the first attempt to address the fate of a GPI-anchor SP and identify a role for the P238S mutation, suggesting the possibility that the PrP GPI-anchor SP could play a role in neurodegenerative prion diseases. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Truncated forms of the prion protein PrP demonstrate the need for complexity in prion structure.

    Science.gov (United States)

    Wan, William; Stöhr, Jan; Kendall, Amy; Stubbs, Gerald

    2015-01-01

    Self-propagation of aberrant protein folds is the defining characteristic of prions. Knowing the structural basis of self-propagation is essential to understanding prions and their related diseases. Prion rods are amyloid fibrils, but not all amyloids are prions. Prions have been remarkably intractable to structural studies, so many investigators have preferred to work with peptide fragments, particularly in the case of the mammalian prion protein PrP. We compared the structures of a number of fragments of PrP by X-ray fiber diffraction, and found that although all of the peptides adopted amyloid conformations, only the larger fragments adopted conformations that modeled the complexity of self-propagating prions, and even these fragments did not always adopt the PrP structure. It appears that the relatively complex structure of the prion form of PrP is not accessible to short model peptides, and that self-propagation may be tied to a level of structural complexity unobtainable in simple model systems. The larger fragments of PrP, however, are useful to illustrate the phenomenon of deformed templating (heterogeneous seeding), which has important biological consequences.

  13. Chaperone use during intimate examinations in primary care: postal survey of family physicians

    OpenAIRE

    Upshur Ross EG; Tracy C Shawn; Price David H

    2005-01-01

    Abstract Background Physicians have long been advised to have a third party present during certain parts of a physical examination; however, little is known about the frequency of chaperone use for those specific intimate examinations regularly performed in primary care. We aimed to determine the frequency of chaperone use among family physicians across a variety of intimate physical examinations for both male and female patients, and also to identify the factors associated with chaperone use...

  14. Post-translational modifications of Hsp90 and their contributions to chaperone regulation

    OpenAIRE

    Mollapour, Mehdi; Neckers, Len

    2011-01-01

    Molecular chaperones, as the name suggests, are involved in folding, maintenance, intracellular transport, and degradation of proteins as well as in facilitating cell signaling. Heat shock protein 90 (Hsp90) is an essential eukaryotic molecular chaperone that carries out these processes in normal and cancer cells. Hsp90 function in vivo is coupled to its ability to hydrolyze ATP and this can be regulated by co-chaperones and post-translational modifications. In this review, we explore the var...

  15. The Cell Wall Polymer Lipoteichoic Acid Becomes Nonessential in Staphylococcus aureus Cells Lacking the ClpX Chaperone

    Directory of Open Access Journals (Sweden)

    Kristoffer T. Bæk

    2016-08-01

    Full Text Available Lipoteichoic acid (LTA is an important cell wall component of Gram-positive bacteria and a promising target for the development of vaccines and antimicrobial compounds against Staphylococcus aureus. Here we demonstrate that mutations in the conditionally essential ltaS (LTA synthase gene arise spontaneously in an S. aureus mutant lacking the ClpX chaperone. A wide variety of ltaS mutations were selected, and among these, a substantial portion resulted in premature stop codons and other changes predicted to abolish LtaS synthesis. Consistent with this assumption, the clpX ltaS double mutants did not produce LTA, and genetic analyses confirmed that LTA becomes nonessential in the absence of the ClpX chaperone. In fact, inactivation of ltaS alleviated the severe growth defect conferred by the clpX deletion. Microscopic analyses showed that the absence of ClpX partly alleviates the septum placement defects of an LTA-depleted strain, while other phenotypes typical of LTA-negative S. aureus mutants, including increased cell size and decreased autolytic activity, are retained. In conclusion, our results indicate that LTA has an essential role in septum placement that can be bypassed by inactivating the ClpX chaperone.

  16. The CAF-1 and Hir Histone Chaperones Associate with Sites of Meiotic Double-Strand Breaks in Budding Yeast.

    Directory of Open Access Journals (Sweden)

    Elsa Brachet

    Full Text Available In the meiotic prophase, programmed DNA double-strand breaks (DSB are introduced along chromosomes to promote homolog pairing and recombination. Although meiotic DSBs usually occur in nucleosome-depleted, accessible regions of chromatin, their repair by homologous recombination takes place in a nucleosomal environment. Nucleosomes may represent an obstacle for the recombination machinery and their timely eviction and reincorporation into chromatin may influence the outcome of recombination, for instance by stabilizing recombination intermediates. Here we show in budding yeast that nucleosomes flanking a meiotic DSB are transiently lost during recombination, and that specific histone H3 chaperones, CAF-1 and Hir, are mobilized at meiotic DSBs. However, the absence of these chaperones has no effect on meiotic recombination, suggesting that timely histone reincorporation following their eviction has no influence on the recombination outcome, or that redundant pathways are activated. This study is the first example of the involvement of histone H3 chaperones at naturally occurring, developmentally programmed DNA double-strand breaks.

  17. The CAF-1 and Hir Histone Chaperones Associate with Sites of Meiotic Double-Strand Breaks in Budding Yeast.

    Science.gov (United States)

    Brachet, Elsa; Béneut, Claire; Serrentino, Maria-Elisabetta; Borde, Valérie

    2015-01-01

    In the meiotic prophase, programmed DNA double-strand breaks (DSB) are introduced along chromosomes to promote homolog pairing and recombination. Although meiotic DSBs usually occur in nucleosome-depleted, accessible regions of chromatin, their repair by homologous recombination takes place in a nucleosomal environment. Nucleosomes may represent an obstacle for the recombination machinery and their timely eviction and reincorporation into chromatin may influence the outcome of recombination, for instance by stabilizing recombination intermediates. Here we show in budding yeast that nucleosomes flanking a meiotic DSB are transiently lost during recombination, and that specific histone H3 chaperones, CAF-1 and Hir, are mobilized at meiotic DSBs. However, the absence of these chaperones has no effect on meiotic recombination, suggesting that timely histone reincorporation following their eviction has no influence on the recombination outcome, or that redundant pathways are activated. This study is the first example of the involvement of histone H3 chaperones at naturally occurring, developmentally programmed DNA double-strand breaks.

  18. Chaperone Use by Residents During Pelvic, Breast, Testicular, and Rectal Exams

    Science.gov (United States)

    Ehrenthal, Deborah B; Farber, Neil J; Collier, Virginia U; Aboff, Brian M

    2000-01-01

    We designed a questionnaire survey to study internal medicine residents' plans to use a chaperone during the pelvic, breast, rectal, and testicular examinations. We found chaperone use by male and female residents differed markedly, and neither group planned to use chaperones universally. When examining female patients, male residents overall were very likely to use a chaperone during a pelvic exam, but less likely for the breast exam and rectal exam. For the female resident, there was a significantly lower likelihood of using chaperones during the pelvic, breast, or rectal exams. There was a much lower rate of chaperone use during the sensitive portions of the male physical examination compared with the female examination, with somewhat higher use by female residents. We concluded that male and female residents differ significantly in their patterns of chaperone use. It would be valuable to develop guidelines for chaperone use to help residents understand the issues involved in the choices, and to protect the residents from the possible medico-legal consequences of forgoing chaperones. PMID:10940150

  19. Antibody persistence after a primary series of a new DTaP-IPV-Hep B-PRP-T combined vaccine or separate DTaP-IPV//PRP-T and hepatitis B vaccines at 2, 4, and 6 months of age and the effect of a subsequent DTaP-IPV//PRP-T booster vaccination at 18 months of age in healthy Argentinean infants.

    Science.gov (United States)

    Tregnaghi, Marcelo; Zambrano, Betzana; Santos-Lima, Eduardo

    2012-01-01

    To assess antibody persistence after vaccination with a new, fully liquid, hexavalent DTaP-IPV-Hep B-PRP-T vaccine at 18 months of age versus licensed DTaP-IPV//PRP-T and hepatitis B (Hep B) vaccines, and to assess the immunogenicity and safety of a subsequent DTaP-IPV//PRP-T booster. A phase III, open-label, single-center study was conducted. Infants previously primed with 3 doses of DTaP-IPV-Hep B-PRP-T (Hexaxim: N = 232 [group 1]) or DTaP-IPV//PRP-T and hepatitis B vaccine (Pentaxim + Engerix B Pediatrico: N = 226 [group 2]) at 2, 4, and 6 months of age received a DTaP-IPV//PRP-T booster at 18 months of age. Antibodies were measured before and 1 month after booster vaccination. Safety was evaluated from parental reports. Analyses were descriptive. Antibody persistence was high and similar in each group for each antigen except for Hep B, for which the percentage (95% confidence interval) of participants with a titer of ≥ 10 mIU/mL was higher in group 2 (99.5% [97.5%, 100.0%]) than in group 1 (85.5% [80.3%, 89.8%]). Postbooster seroprotection (diphtheria, tetanus, inactivated poliovirus, polyribosyl-ribitol phosphate) and serconversion (pertussis toxoid, filamentous hemagglutinin) rates were high and similar in each group, and geometric mean antibody concentrations increased markedly in both groups. Safety after the booster vaccination was good and independent of the primary-series vaccine, although one serious adverse event of convulsions was considered to be vaccine related. The DTaP-IPV/PRP-T booster vaccination at 18 months of age was similarly immunogenic and well tolerated after primary-series vaccination with either the investigational hexavalent vaccine or the reference pentavalent vaccine. This confirms the suitability of a booster vaccination of DTaP-IPV//PRP-T after a primary series of the new DTaP-IPV-Hep B-PRP-T vaccine.

  20. PRP Comments for ICF Q1/Q2 FY17 Experiments 3/10/16

    Energy Technology Data Exchange (ETDEWEB)

    Kauffman, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-04-14

    The PRP generally endorsed the Program plan during the short time for discussions. We agree that the strategy to develop a hohlraum that is symmetric and has low laser-plasma instabilities and to develop an alternative method for supporting the capsule is the best path forward for making progress in understanding ignition performance. The Program is oriented toward a milestone in 2020 for “determining the efficacy of NIF for ignition and credible physics-scaling to multi-megajoule yields for all ICF approaches.” We are concerned that the time and resources are not sufficient to vet all of the various approaches that are being pursued to make an informed decision by this date. For NIF to meet this goal, a process will be needed to to select the most promising paths forward. We recommend that the Program develop this process for selecting the path forward to optimize resources. We were glad to see that the direct drive program took our comments under consideration. We think that the proposed experiments have the program headed in a better direction. The PRP had only a short time to discuss the detailed experimental proposals. The following are comments on the detailed proposals. We did not have time to discuss them as a group. They represent individual opinions and provided to you as feedback to your proposals.

  1. A modified three-term PRP conjugate gradient algorithm for optimization models.

    Science.gov (United States)

    Wu, Yanlin

    2017-01-01

    The nonlinear conjugate gradient (CG) algorithm is a very effective method for optimization, especially for large-scale problems, because of its low memory requirement and simplicity. Zhang et al. (IMA J. Numer. Anal. 26:629-649, 2006) firstly propose a three-term CG algorithm based on the well known Polak-Ribière-Polyak (PRP) formula for unconstrained optimization, where their method has the sufficient descent property without any line search technique. They proved the global convergence of the Armijo line search but this fails for the Wolfe line search technique. Inspired by their method, we will make a further study and give a modified three-term PRP CG algorithm. The presented method possesses the following features: (1) The sufficient descent property also holds without any line search technique; (2) the trust region property of the search direction is automatically satisfied; (3) the steplengh is bounded from below; (4) the global convergence will be established under the Wolfe line search. Numerical results show that the new algorithm is more effective than that of the normal method.

  2. A DTAP–IPV//PRP~T VACCINE: A REVIEW OF 16 YEARS’ CLINICAL EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Stanley A. Plotkin

    2012-01-01

    Full Text Available Owing to their low reactogenicity, confirmed efficacy and availability in combination vaccines, acellular pertussis (aP-inactivated poliovirus (IPV combined vaccines are now included in various national immunization programs worldwide. We provide an overview of 16 years of clinical experience with a diphtheria (D, tetanus (T, aP, IPV and Haemophilus influenzae type b (Hib polysaccharide conjugated to tetanus protein (PRP~T combined vaccine (DTaP–IPV//PRP~T — Pentaxim, Sanofi Pasteur, France. Good immunogenicity has been demonstrated after primary vaccination with Pentaxim, regardless of the population ethnicity and primary vaccination schedule. A booster vaccination in the second year of life also resulted in a high immune response for each antigen. Furthermore, 10 years of national surveillance in Sweden has demonstrated the effectiveness of Pentaxim in controlling pertussis. As is the case for other aP-containing combined vaccines, Pentaxim is well tolerated, with the safety profile being better than for whole-cell pertussiscontaining combination vaccines for primary and booster vaccinations.

  3. Prediction and optimization of the recovery rate in centrifugal separation of platelet-rich plasma (PRP)

    Science.gov (United States)

    Piao, Linfeng; Park, Hyungmin; Jo, Chris

    2016-11-01

    We present a theoretical model of the recovery rate of platelet and white blood cell in the process of centrifugal separation of platelet-rich plasma (PRP). For the practically used conditions in the field, the separation process is modeled as a one-dimensional particle sedimentation; a quasi-linear partial differential equation is derived based on the kinematic-wave theory. This is solved to determine the interface positions between supernatant-suspension and suspension-sediment, used to estimate the recovery rate of the plasma. While correcting the Brown's hypothesis (1989) claiming that the platelet recovery is linearly proportional to that of plasma, we propose a new correlation model for prediction of the platelet recovery, which is a function of the volume of whole blood, centrifugal acceleration and time. For a range of practical parameters, such as hematocrit, volume of whole blood and centrifugation (time and acceleration), the predicted recovery rate shows a good agreement with available clinical data. We propose that this model is further used to optimize the preparation method of PRP that satisfies the customized case. Supported by a Grant (MPSS-CG-2016-02) through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

  4. CLINICAL RESULTS FROM THE TREATMENT OF CHRONIC SKIN WOUNDS WITH PLATELET RICH PLASMA (PRP

    Directory of Open Access Journals (Sweden)

    Pencho Kossev

    2015-12-01

    Full Text Available PURPOSE: To show platelet rich plasma (PRP application of chronic skin wounds and to evaluate the results from the treatment. MATERIAL AND METHODS: A total of 14 patients with problematic skin wounds had been treated at the clinic for a period of five years (from May 2009 to December 2014 with the following patient sex ratio: male patients - 5 and female patients - 9. Average age - 48,5 (30-76. Patients with Type 2 Diabetes - 4, with decubitus ulcers - 6, traumatic - 8, with infection - 5. Based on a scheme developed by us, all cases were treated by administering platelet-rich plasma, derived by PRGF Endoret system. Follow-up period was within 4 - 6 months (4,5 on average. RESULTS: The results have been evaluated based on the following functional scoring systems - Total wound score, Total anatomic score and Total score (20. The baseline values at the very beginning of the follow-up period were as follows: Total wound score - 12 p.; Total anatomic score - 10 p., Total score - 17 p. By the end of the treatment period the score was 0 p., which means excellent results, i.e. complete healing of the wounds. CONCLUSION: We believe that the application of PRP may become optimal therapy in the treatment of difficult to heal wounds around joints, bone, subject tendons, plantar surface of the foot, etc., as it opens new perspectives in the field of human tissue regeneration.

  5. Two for the Price of One: A Neuroprotective Chaperone Kit within NAD Synthase Protein NMNAT2.

    Directory of Open Access Journals (Sweden)

    Angela Lavado-Roldán

    2016-07-01

    Full Text Available One of the most fascinating properties of the brain is the ability to function smoothly across decades of a lifespan. Neurons are nondividing mature cells specialized in fast electrical and chemical communication at synapses. Often, neurons and synapses operate at high levels of activity through sophisticated arborizations of long axons and dendrites that nevertheless stay healthy throughout years. On the other hand, aging and activity-dependent stress strike onto the protein machineries turning proteins unfolded and prone to form pathological aggregates associated with neurodegeneration. How do neurons protect from those insults and remain healthy for their whole life? Ali and colleagues now present a molecular mechanism by which the enzyme nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2 acts not only as a NAD synthase involved in axonal maintenance but as a molecular chaperone helping neurons to overcome protein unfolding and protein aggregation.

  6. The co-chaperone p23 is degraded by caspases and the proteasome during apoptosis

    DEFF Research Database (Denmark)

    Mollerup, Jens; Berchtold, Martin Werner

    2005-01-01

    The heat shock protein 90 co-chaperone p23 has recently been shown to be up-regulated in cancer cells and down-regulated in atheroschlerotic plaques. We found that p23 is degraded during apoptosis induced by several stimuli, including Fas and TNFa-receptor activation as well as staurosporine...... treatment. Caspase inhibition protected p23 from degradation in several cell lines. In addition, recombinant caspase-3 and 8 cleaved p23 at Asp 142 generating a degradation product of 18 kDa as seen in apoptotic cells. Truncated p23 is further degraded in a proteasome dependent process during apoptosis....... Furthermore, we found that the anti-aggregating activity of truncated p23 was reduced compared to full length p23 indicating that caspase mediated p23 degradation contributes to protein destabilisation in apoptosis....

  7. Modulation of chaperone-like and membranolytic activities of major ...

    Indian Academy of Sciences (India)

    The HSP-1/2–L-carnitine complex exhibits anti-oxidative behaviour by inhibiting the production ofhydroxyl radicals, suggesting that it can protect other constituents of seminal plasma from damage by hydroxyl radicals. AsHSP-1/2 and L-carnitine share the same spatiotemporal location in the horse reproductive tract, this ...

  8. Modulation of chaperone-like and membranolytic activities of major ...

    Indian Academy of Sciences (India)

    C Sudheer Kumar

    2017-06-20

    Jun 20, 2017 ... ologically significant and may prevent premature interaction of HSP-1/2 with sperm, which in turn regulates the sperm capacitation. Keywords. ... proteins present in the seminal plasma bind to the sperm surface and play a major ..... proximal parts of the epididymal lumen contain unde- tectable amounts of ...

  9. Improved 1, 2, 4-butanetriol production from an engineered Escherichia coli by co-expression of different chaperone proteins.

    Science.gov (United States)

    Lu, Xinyao; He, Shuying; Zong, Hong; Song, Jian; Chen, Wen; Zhuge, Bin

    2016-09-01

    1, 2, 4-Butanetriol (BT) is a high-value non-natural chemical and has important applications in polymers, medical production and military industry. In the constructed BT biosynthesis pathway from xylose in Escherichia coli, the xylose dehydrogenase (Xdh) and the benzoylformate decarboxylase (MdlC) are heterologous enzymes and the activity of MdlC is the key limiting factor for BT production. In this study, six chaperone protein systems were introduced into the engineered E. coli harboring the recombinant BT pathway. The chaperone GroES-GroEL was beneficial to Xdh activity but had a negative effect on MdlC activity and BT titer. The plasmid pTf16 containing the tig gene (trigger factor) was beneficial to Xdh and MdlC activities and improved the BT titer from 0.42 to 0.56 g/l from 20 g/l xylose. However, co-expression of trigger factor and GroES-GroEL simultaneously reduced the activity of MdlC and had no effect on the BT production. The plasmid pKJE7 harboring dnaK-dnaJ-grpE showed significant negative effects on these enzyme activities and cell growth, leading to completely restrained the BT production. Similarly, co-expression of DnaKJ-GrpPE and GroES-GroEL simultaneously reduced Xdh and MdlC activities and decreased the BT titer by 45.2 %. The BT production of the engineered E. coli harboring pTf16 was further improved to the highest level at 1.01 g/l under pH control (pH 7). This work showed the potential application of chaperone proteins in microorganism engineering to get high production of target compounds as an effective and valuable tool.

  10. Knee Osteoarthritis Injection Choices: Platelet- Rich Plasma (PRP versus Hyaluronic Acid (A one-year randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Seyed Ahmad Raeissadat

    2015-01-01

    Full Text Available Introduction Knee osteoarthritis (OA is the most common articular disease. Different methods are used to alleviate the symptoms of patients with knee OA, including analgesics, physical therapy, exercise prescription, and intra-articular injections (glucocorticoids, hyaluronic acid [HA], etc. New studies have focused on modern therapeutic methods that stimulate cartilage healing process and improve the damage, including the use of platelet-rich plasma (PRP as a complex of growth factors. Due to the high incidence of OA and its consequences, we decided to study the long-term effect of intraarticular injection of PRP and HA on clinical outcome and quality of life of patients with knee OA. Method This non-placebo-controlled randomized clinical trial involved 160 patients affected by knee OA, grade 1–4 of Kellgren–Lawrence scale. In the PRP group ( n = 87, two intra-articular injections at 4-week interval were applied, and in the HA group ( n = 73, three doses of intra-articular injection at 1-week interval were applied. All patients were prospectively evaluated before and at 12 months after the treatment by Western Ontario and McMaster Universities Arthritis Index (WOMAC and SF-36 questionnaires. The results were analyzed using SPSS 16.1 software (RCT code: IRCT2014012113442N5. Results At the 12-month follow-up, WOMAC pain score and bodily pain significantly improved in both groups; however, better results were determined in the PRP group compared to the HA group ( P < 0.001. Other WOMAC and SF-36 parameters improved only in the PRP group. More improvement (but not statistically significant was achieved in patients with grade 2 OA in both the groups. Conclusion This study suggests that PRP injection is more efficacious than HA injection in reducing symptoms and improving quality of life and is a therapeutic option in select patients with knee OA who have not responded to conventional treatment.

  11. Roles of Intramolecular and Intermolecular Interactions in Functional Regulation of the Hsp70 J-protein Co-Chaperone Sis1

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hyun Young; Ziegelhoffer, Thomas; Osipiuk, Jerzy; Ciesielski, Szymon J.; Baranowski, Maciej; Zhou, Min; Joachimiak, Andrzej; Craig, Elizabeth A.

    2015-04-01

    Unlike other Hsp70 molecular chaperones, those of the eukaryotic cytosol have four residues, EEVD, at heir C-termini. EEVD(Hsp70) binds adaptor proteins of the Hsp90 chaperone system and mitochondrial membrane preprotein receptors, thereby facilitating processing of Hsp70-bound clients through protein folding and translocation pathways. Among J-protein co-chaperones functioning in these pathways, Sis1 is unique, as it also binds the EEVD(Hsp70) motif. However, little is known about the role of the Sis1:EEVD(Hsp70) interaction. We found that deletion of EEVD(Hsp70) abolished the ability of Sis1, but not the ubiquitous J-protein Ydj1, to partner with Hsp70 in in vitro protein refolding. Sis1 co-chaperone activity with Hsp70ΔEEVD was restored upon substitution of a glutamic acid of the J-domain. Structural analysis revealed that this key glutamic acid, which is not present in Ydj1, forms a salt bridge with an arginine of the immediately adjacent glycine-rich region. Thus, restoration of Sis1 in vitro activity suggests that intramolecular interactions between the J-domain and glycine-rich region control co-chaperone activity, which is optimal only when Sis1 interacts with the EEVD(Hsp70) motif. However, we found that disruption of the Sis1:EEVD(Hsp70) interaction enhances the ability of Sis1 to substitute for Ydj1 in vivo. Our results are consistent with the idea that interaction of Sis1 with EEVD(Hsp70) minimizes transfer of Sis1-bound clients to Hsp70s that are primed for client transfer to folding and translocation pathways by their preassociation with EEVD binding adaptor proteins. These interactions may be one means by which cells triage Ydj1- and Sis1-bound clients to productive and quality control pathways, respectively.

  12. Oxidation reduces the fibrillation but not the neurotoxicity of the prion peptide PrP106-126

    DEFF Research Database (Denmark)

    Bergstrøm, Linda Alice; Chabry, J.; Bastholm, L.

    2007-01-01

    There is increasing evidence that soluble oligomers of misfolded protein may play a role in the pathogenesis of protein misfolding diseases including the transmissible spongiform encephalopathies (TSE) where the protein involved is the prion protein, PrP. The effect of oxidation on fibrillation...... tendency and neurotoxicity of different molecular variants of the prion peptide PrP106-126 was investigated. It was found that methionine oxidation significantly reduced amyloid fibril formation and proteinase K resistance, but it did not reduce (but rather increase slightly) the neurotoxicity...

  13. Platelet rich plasma (PRP) induces chondroprotection via increasing autophagy, anti-inflammatory markers, and decreasing apoptosis in human osteoarthritic cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Moussa, Mayssam, E-mail: Moussa-mayssam@hotmail.com [Regenerative medicine and inflammation Laboratory, Faculty of Medicine, Saint-Joseph University, Beirut (Lebanon); Lajeunesse, Daniel, E-mail: daniel.lajeunesse@umontreal.ca [Research Centre in Osteoarthritis, Research Centre in Monteral University (Canada); Hilal, George, E-mail: George2266@gmail.com [Cancer and metabolism Laboratory, Faculty of Medicine, Saint-Joseph University, Beirut (Lebanon); El Atat, Oula, E-mail: oulaatat@hotmail.com [Regenerative medicine and inflammation Laboratory, Faculty of Medicine, Saint-Joseph University, Beirut (Lebanon); Haykal, Gaby, E-mail: Gaby.haykal@hdf.usj.edu.lb [Hotel Dieu de France, Faculty of Medicine, Saint-Joseph University, Beirut (Lebanon); Serhal, Rim, E-mail: rim.basbous@gmail.com [Regenerative medicine and inflammation Laboratory, Faculty of Medicine, Saint-Joseph University, Beirut (Lebanon); Chalhoub, Antonio, E-mail: Mava.o@hotmail.com [Carantina Hospital, Beirut (Lebanon); Khalil, Charbel, E-mail: charbelk3@hotmail.com [Regenerative medicine and inflammation Laboratory, Faculty of Medicine, Saint-Joseph University, Beirut (Lebanon); Alaaeddine, Nada, E-mail: Nada.aladdin@gmail.com [Regenerative medicine and inflammation Laboratory, Faculty of Medicine, Saint-Joseph University, Beirut (Lebanon)

    2017-03-01

    Objectives: Autophagy constitutes a defense mechanism to overcome aging and apoptosis in osteoarthritic cartilage. Several cytokines and transcription factors are linked to autophagy and play an important role in the degradative cascade in osteoarthritis (OA). Cell therapy such as platelet rich plasma (PRP) has recently emerged as a promising therapeutic tool for many diseases including OA. However, its mechanism of action on improving cartilage repair remains to be determined. The purpose of this study is to investigate the effect of PRP on osteoarthritic chondrocytes and to elucidate the mechanism by which PRP contributes to cartilage regeneration. Methods: Osteoarthritic chondrocytes were co-cultured with an increasing concentration of PRP obtained from healthy donors. The effect of PRP on the proliferation of chondrocytes was performed using cell counting and WST8 proliferation assays. Autophagy, apoptosis and intracellular level of IL-4, IL-10, and IL-13 were determined using flow cytometry analyses. Autophagy markers BECLIN and LC3II were also determined using quantitative polymerase chain reaction (qPCR). qPCR and ELISA were used to measure the expression of ADAMDTS-5, MMP3, MMP13, TIMP-1–2–3, aggregan, Collagen type 2, TGF-β, Cox-2, Il-6, FOXO1, FOXO3, and HIF-1 in tissues and co-cultured media. Results: PRP increased significantly the proliferation of chondrocytes, decreased apoptosis and increased autophagy and its markers along with its regulators FOXO1, FOXO3 and HIF-1 in osteoarthritic chondrocytes. Furthermore, PRP caused a dose-dependent significant decrease in MMP3, MMP13, and ADAMTS-5, IL-6 and COX-2 while increasing TGF-β, aggregan, and collagen type 2, TIMPs and intracellular IL-4, IL-10, IL-13. Conclusion: These results suggest that PRP could be a potential therapeutic tool for the treatment of OA. - Highlights: • Platelet Rich Plasma is suggested as a new treatment for osteoarthritis. • The proposed therapeutic effect is

  14. Translational autocontrol of the Escherichia coli hfq RNA chaperone gene.

    Science.gov (United States)

    Vecerek, Branislav; Moll, Isabella; Bläsi, Udo

    2005-06-01

    The conserved bacterial RNA chaperone Hfq has been shown to play an important role in post-transcriptional regulation. Here, we demonstrate that Hfq synthesis is autoregulated at the translational level. We have mapped two Hfq binding sites in the 5'-untranslated region of hfq mRNA and show that Hfq binding inhibits formation of the translation initiation complex. In vitro translation and in vivo studies further revealed that Hfq binding to both sites is required for efficient translational repression of hfq mRNA.

  15. Endoplasmic reticulum proteins SDF2 and SDF2L1 act as components of the BiP chaperone cycle to prevent protein aggregation.

    Science.gov (United States)

    Fujimori, Tsutomu; Suno, Ryoji; Iemura, Shun-Ichiro; Natsume, Tohru; Wada, Ikuo; Hosokawa, Nobuko

    2017-08-01

    The folding of newly synthesized proteins in the endoplasmic reticulum (ER) is assisted by ER-resident chaperone proteins. BiP (immunoglobulin heavy-chain-binding protein), a member of the HSP70 family, plays a central role in protein quality control. The chaperone function of BiP is regulated by its intrinsic ATPase activity, which is stimulated by ER-resident proteins of the HSP40/DnaJ family, including ERdj3. Here, we report that two closely related proteins, SDF2 and SDF2L1, regulate the BiP chaperone cycle. Both are ER-resident, but SDF2 is constitutively expressed, whereas SDF2L1 expression is induced by ER stress. Both luminal proteins formed a stable complex with ERdj3 and potently inhibited the aggregation of different types of misfolded ER cargo. These proteins associated with non-native proteins, thus promoting the BiP-substrate interaction cycle. A dominant-negative ERdj3 mutant that inhibits the interaction between ERdj3 and BiP prevented the dissociation of misfolded cargo from the ERdj3-SDF2L1 complex. Our findings indicate that SDF2 and SDF2L1 associate with ERdj3 and act as components in the BiP chaperone cycle to prevent the aggregation of misfolded proteins, partly explaining the broad folding capabilities of the ER under various physiological conditions. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  16. Immunogenicity and safety study of a new DTaP-IPV-Hep B-PRP-T combined vaccine compared to a licensed DTaP-IPV-Hep B//PRP-T comparator, both concomitantly administered with a 7-valent pneumococcal conjugate vaccine at 2, 4, and 6 months of age in Thai infants.

    Science.gov (United States)

    Kosalaraksa, Pope; Thisyakorn, Usa; Benjaponpitak, Suwat; Chokephaibulkit, Kulkanya; Santos-Lima, Eduardo

    2011-04-01

    To assess a new, fully-liquid, hexavalent DTaP-IPV-Hep B-PRP-T vaccine (diphtheria toxoid (D), tetanus toxoid (T), acellular pertussis (aP), inactivated poliovirus (IPV), hepatitis B (Hep B), and Haemophilus influenzae type b polysaccharide conjugated to tetanus protein (PRP-T) antigens) compared to a licensed DTaP-IPV-Hep B//PRP-T vaccine following primary series co-administration with a 7-valent pneumococcal conjugate vaccine (PCV7). This was a randomized, phase III, observer-blind study in Thai infants (N=412), who received DTaP-IPV-Hep B-PRP-T or DTaP-IPV-Hep B//PRP-T at 2, 4, and 6 months of age, co-administered with PCV7. All received Hep B at birth. Non-inferiority for Hep B ≥ 10 mIU/ml and PRP ≥0.15μg/ml was analyzed (DTaP-IPV-Hep B-PRP-T relative to DTaP-IPV-Hep B//PRP-T) at 1 month post-primary. Seroprotection/seroconversion and geometric mean titers (GMTs) were analyzed descriptively for all hexavalent components. Safety was evaluated from parental reports. Anti-Hep B and anti-PRP antibody seroprotection rates were high for DTaP-IPV-Hep B-PRP-T (n=189) and DTaP-IPV-Hep B//PRP-T (n=190), and non-inferiority was demonstrated. Anti-D and anti-T ≥ 0.01 IU/ml, anti-polio types 1, 2, and 3 ≥ 8 (1/dil), and anti-PT and anti-FHA seroconversion were high and similar in each group. For DTaP-IPV-Hep B-PRP-T and DTaP-IPV-Hep B//PRP-T, anti-Hep B ≥ 100 mIU/ml was 98.4% and 99.5% (GMTs 2477 and 2442 mIU/ml), respectively; anti-PRP ≥ 1.0 μg/ml was 85.2% and 71.1% (GMTs 5.07 and 2.41 μg/ml), respectively. Safety profiles were comparable. There were no vaccine-related serious adverse events. Following co-administration with PCV7 the investigational DTaP-IPV-Hep B-PRP-T vaccine was safe and immunogenic. Non-inferiority to DTaP-IPV-Hep B//PRP-T was shown for Hep B and PRP. Copyright © 2011 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  17. The cellular chaperone hsc70 is specifically recruited to reovirus viral factories independently of its chaperone function.

    Science.gov (United States)

    Kaufer, Susanne; Coffey, Caroline M; Parker, John S L

    2012-01-01

    Mammalian orthoreoviruses replicate and assemble in the cytosol of infected cells. A viral nonstructural protein, μNS, forms large inclusion-like structures called viral factories (VFs) in which assembling viral particles can be identified. Here we examined the localization of the cellular chaperone Hsc70 and found that it colocalizes with VFs in infected cells and also with viral factory-like structures (VFLs) formed by ectopically expressed μNS. Small interfering RNA (siRNA)-mediated knockdown of Hsc70 did not affect the formation or maintenance of VFLs. We further showed that dominant negative mutants of Hsc70 were also recruited to VFLs, indicating that Hsc70 recruitment to VFLs is independent of the chaperone function. In support of this finding, μNS was immunoprecipitated with wild-type Hsc70, with a dominant negative mutant of Hsc70, and with the minimal substrate-binding site of Hsc70 (amino acids 395 to 540). We identified a minimal region of μNS between amino acids 222 and 271 that was sufficient for the interaction with Hsc70. This region of μNS has not been assigned any function previously. However, neither point mutants with alterations in this region nor the complete deletion of this domain abrogated the μNS-Hsc70 interaction, indicating that a second portion of μNS also interacts with Hsc70. Taken together, these findings suggest a specific chaperone function for Hsc70 within viral factories, the sites of reovirus replication and assembly in cells.

  18. Beneficios del adhesivo autólogo de fibrina y PRP en ritidectomía

    Directory of Open Access Journals (Sweden)

    I. Hernández

    2015-09-01

    Full Text Available Determinamos la eficacia clínica del adhesivo autólogo de fibrina y la fracción de sangre rica en plaquetas (PRP en la disminución de complicaciones en ritidectomía. Se intervino con igual técnica ambas hemicaras, pero solo una, aleatoriamente, recibió tratamiento con hemoderivados. Estudiamos comparativamente la evolución postquirúrgica de una hemicara frente a otra: tiempo de recuperación a corto, medio y largo plazo; incidencia de hematomas, seromas, epidermolisis, necrosis y equimosis; y satisfacción con los resultados. Todos los datos recogidos fueron analizados estadísticamente. Realizamos un estudio clínico prospectivo en fase I, randomizado y a doble ciego, en una muestra de 19 pacientes, mayores de 50 años, sometidos a ritidectomía. A todos se les aplicó por goteo las fracciones de fibrina y PRP en la hemicara seleccionada hasta cubrir toda el área quirúrgica antes del cierre con suturas: sienes, mejillas y cuello. El tratamiento se completó en ambas hemicaras con drenaje laminar durante 24 horas y vendaje oclusivo durante 72 horas. Las hemicaras que presentaron menos complicaciones, evolucionaron mejor y de forma más rápida fueron las tratadas con la composición de hemoderivados. En todas, el tiempo de recuperación promedio fue un 48% menor respecto a las no tratadas. Las equimosis fueron más evidentes en las hemicaras no tratadas y solo en ellas se desarrollaron hematomas. La cicatrización con epidermolisis de los bordes de los colgajos se observó en 10 casos: 2 en hemicara tratadas con hemoderivados y 8 en las hemicaras control. Las hemicaras tratadas evolucionaron más rápidamente, sin secuelas cicatriciales y con notable satisfacción por parte de los pacientes. Concluimos que el efecto del adhesivo autólogo de fibrina combinado con PRP en las ritidectomías reduce la incidencia de seromas, equimosis, epidermólisis y el tiempo de recuperación, y favorece una evidente supervivencia de la cicatrizaci

  19. Modulation of polyglutamine inclusion formation by the Hsp70 chaperone machine

    NARCIS (Netherlands)

    Rujano, M. A.; Kampinga, H. H.; Salomons, F. A.

    2007-01-01

    Components of the Hsp70 chaperone machine have been implied in protection against polyglutamine (poly-Q) pathologies. Yet, little is known about specific mechanisms and the rate-limiting components that account for this protective effect. Here, we examined the effects of an Hsp70 chaperone family

  20. Model systems of protein-misfolding diseases reveal chaperone modifiers of proteotoxicity

    Directory of Open Access Journals (Sweden)

    Marc Brehme

    2016-08-01

    Full Text Available Chaperones and co-chaperones enable protein folding and degradation, safeguarding the proteome against proteotoxic stress. Chaperones display dynamic responses to exogenous and endogenous stressors and thus constitute a key component of the proteostasis network (PN, an intricately regulated network of quality control and repair pathways that cooperate to maintain cellular proteostasis. It has been hypothesized that aging leads to chronic stress on the proteome and that this could underlie many age-associated diseases such as neurodegeneration. Understanding the dynamics of chaperone function during aging and disease-related proteotoxic stress could reveal specific chaperone systems that fail to respond to protein misfolding. Through the use of suppressor and enhancer screens, key chaperones crucial for proteostasis maintenance have been identified in model organisms that express misfolded disease-related proteins. This review provides a literature-based analysis of these genetic studies and highlights prominent chaperone modifiers of proteotoxicity, which include the HSP70-HSP40 machine and small HSPs. Taken together, these studies in model systems can inform strategies for therapeutic regulation of chaperone functionality, to manage aging-related proteotoxic stress and to delay the onset of neurodegenerative diseases.

  1. Structure of Spa15, a type III secretion chaperone from Shigella flexneri with broad specificity

    NARCIS (Netherlands)

    Eerde, André van; Hamiaux, Cyril; Pérez, Javier; Parsot, Claude; Dijkstra, Bauke W.

    2004-01-01

    Type III secretion (TTS) systems are used by many Gram-negative pathogens to inject virulence proteins into the cells of their hosts. Several of these virulence effectors require TTS chaperones that maintain them in a secretion-competent state. Whereas most chaperones bind only one effector, Spa15

  2. Oral pharmacological chaperone migalastat compared with enzyme replacement therapy in Fabry disease

    DEFF Research Database (Denmark)

    Hughes, Derralynn A; Nicholls, Kathleen; Shankar, Suma P

    2017-01-01

    BACKGROUND: Fabry disease is an X-linked lysosomal storage disorder caused by GLA mutations, resulting in α-galactosidase (α-Gal) deficiency and accumulation of lysosomal substrates. Migalastat, an oral pharmacological chaperone being developed as an alternative to intravenous enzyme replacement...... therapy (ERT), stabilises specific mutant (amenable) forms of α-Gal to facilitate normal lysosomal trafficking. METHODS: The main objective of the 18-month, randomised, active-controlled ATTRACT study was to assess the effects of migalastat on renal function in patients with Fabry disease previously...... treated with ERT. Effects on heart, disease substrate, patient-reported outcomes (PROs) and safety were also assessed. RESULTS: Fifty-seven adults (56% female) receiving ERT (88% had multiorgan disease) were randomised (1.5:1), based on a preliminary cell-based assay of responsiveness to migalastat...

  3. Synthetic cation-selective nanotube: permeant cations chaperoned by anions.

    Science.gov (United States)

    Hilder, Tamsyn A; Gordon, Dan; Chung, Shin-Ho

    2011-01-28

    The ability to design ion-selective, synthetic nanotubes which mimic biological ion channels may have significant implications for the future treatment of bacteria, diseases, and as ultrasensitive biosensors. We present the design of a synthetic nanotube made from carbon atoms that selectively allows monovalent cations to move across and rejects all anions. The cation-selective nanotube mimics some of the salient properties of biological ion channels. Before practical nanodevices are successfully fabricated it is vital that proof-of-concept computational studies are performed. With this in mind we use molecular and stochastic dynamics simulations to characterize the dynamics of ion permeation across a single-walled (10, 10), 36 Å long, carbon nanotube terminated with carboxylic acid with an effective radius of 5.08 Å. Although cations encounter a high energy barrier of 7 kT, its height is drastically reduced by a chloride ion in the nanotube. The presence of a chloride ion near the pore entrance thus enables a cation to enter the pore and, once in the pore, it is chaperoned by the resident counterion across the narrow pore. The moment the chaperoned cation transits the pore, the counterion moves back to the entrance to ferry another ion. The synthetic nanotube has a high sodium conductance of 124 pS and shows linear current-voltage and current-concentration profiles. The cation-anion selectivity ratio ranges from 8 to 25, depending on the ionic concentrations in the reservoirs.

  4. Structural Analysis of the Rubisco-Assembly Chaperone RbcX-II from Chlamydomonas reinhardtii.

    Directory of Open Access Journals (Sweden)

    Andreas Bracher

    Full Text Available The most prevalent form of the Rubisco enzyme is a complex of eight catalytic large subunits (RbcL and eight regulatory small subunits (RbcS. Rubisco biogenesis depends on the assistance by specific molecular chaperones. The assembly chaperone RbcX stabilizes the RbcL subunits after folding by chaperonin and mediates their assembly to the RbcL8 core complex, from which RbcX is displaced by RbcS to form active holoenzyme. Two isoforms of RbcX are found in eukaryotes, RbcX-I, which is more closely related to cyanobacterial RbcX, and the more distant RbcX-II. The green algae Chlamydomonas reinhardtii contains only RbcX-II isoforms, CrRbcX-IIa and CrRbcX-IIb. Here we solved the crystal structure of CrRbcX-IIa and show that it forms an arc-shaped dimer with a central hydrophobic cleft for binding the C-terminal sequence of RbcL. Like other RbcX proteins, CrRbcX-IIa supports the assembly of cyanobacterial Rubisco in vitro, albeit with reduced activity relative to cyanobacterial RbcX-I. Structural analysis of a fusion protein of CrRbcX-IIa and the C-terminal peptide of RbcL suggests that the peptide binding mode of RbcX-II may differ from that of cyanobacterial RbcX. RbcX homologs appear to have adapted to their cognate Rubisco clients as a result of co-evolution.

  5. The chaperone role of the pyridoxal 5'-phosphate and its implications for rare diseases involving B6-dependent enzymes.

    Science.gov (United States)

    Cellini, Barbara; Montioli, Riccardo; Oppici, Elisa; Astegno, Alessandra; Voltattorni, Carla Borri

    2014-02-01

    The biologically active form of the B6 vitamers is pyridoxal 5'-phosphate (PLP), which plays a coenzymatic role in several distinct enzymatic activities ranging from the synthesis, interconversion and degradation of amino acids to the replenishment of one-carbon units, synthesis and degradation of biogenic amines, synthesis of tetrapyrrolic compounds and metabolism of amino-sugars. In the catalytic process of PLP-dependent enzymes, the substrate amino acid forms a Schiff base with PLP and the electrophilicity of the PLP pyridine ring plays important roles in the subsequent catalytic steps. While the essential role of PLP in the acquisition of biological activity of many proteins is long recognized, the finding that some PLP-enzymes require the coenzyme for refolding in vitro points to an additional role of PLP as a chaperone in the folding process. Mutations in the genes encoding PLP-enzymes are causative of several rare inherited diseases. Patients affected by some of these diseases (AADC deficiency, cystathionuria, homocystinuria, gyrate atrophy, primary hyperoxaluria type 1, xanthurenic aciduria, X-linked sideroblastic anaemia) can benefit, although at different degrees, from the administration of pyridoxine, a PLP precursor. The effect of the coenzyme is not limited to mutations that affect the enzyme-coenzyme interaction, but also to those that cause folding defects, reinforcing the idea that PLP could play a chaperone role and improve the folding efficiency of misfolded variants. In this review, recent biochemical and cell biology studies highlighting the chaperoning activity of the coenzyme on folding-defective variants of PLP-enzymes associated with rare diseases are presented and discussed. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  6. Recombinant PrP and Its Contribution to Research on Transmissible Spongiform Encephalopathies

    Directory of Open Access Journals (Sweden)

    Jorge M. Charco

    2017-12-01

    Full Text Available The misfolding of the cellular prion protein (PrPC into the disease-associated isoform (PrPSc and its accumulation as amyloid fibrils in the central nervous system is one of the central events in transmissible spongiform encephalopathies (TSEs. Due to the proteinaceous nature of the causal agent the molecular mechanisms of misfolding, interspecies transmission, neurotoxicity and strain phenomenon remain mostly ill-defined or unknown. Significant advances were made using in vivo and in cellula models, but the limitations of these, primarily due to their inherent complexity and the small amounts of PrPSc that can be obtained, gave rise to the necessity of new model systems. The production of recombinant PrP using E. coli and subsequent induction of misfolding to the aberrant isoform using different techniques paved the way for the development of cell-free systems that complement the previous models. The generation of the first infectious recombinant prion proteins with identical properties of brain-derived PrPSc increased the value of cell-free systems for research on TSEs. The versatility and ease of implementation of these models have made them invaluable for the study of the molecular mechanisms of prion formation and propagation, and have enabled improvements in diagnosis, high-throughput screening of putative anti-prion compounds and the design of novel therapeutic strategies. Here, we provide an overview of the resultant advances in the prion field due to the development of recombinant PrP and its use in cell-free systems.

  7. PLATELET-RICH PLASMA (PRP FOR THE TREATMENT OF PROBLEMATIC SKIN WOUNDS

    Directory of Open Access Journals (Sweden)

    Tsvetan Sokolov

    2016-12-01

    Full Text Available OBJECTIVE: To show platelet-rich plasma (PRP application of problematic skin wounds and to evaluate the results from the treatment. MATERIAL AND METHODS: A total of 31 patients with problematic skin wounds had been treated at the clinic for a period of five years (from May 2010 to September 2015 with the following patient sex ratio: male patients– 13 and female patients– 18. Average age– 46,5 (22-82. Patients with Type 2 Diabetes– 10, with decubitus ulcers– 2, traumatic– 29, with infection– 12, acute– 15, chronic– 16. Based on a scheme developed by us, all cases were treated by administering platelet-rich plasma, derived by PRGF Endoret system. Follow-up period was within 4 – 6 months (4,5 on average. We used platelet rich plasma derived by PRGF Endoret system, applied on the wound bed on a weekly basis. RESULTS: The results have been evaluated based on the following functional scoring systems - Total wound score, Total anatomic score and Total score (20. The baseline values at the very beginning of the follow-up period were as follows: Total wound score – 10 p.; Total anatomic score – 8 p., Total score – 15 p. By the end of the treatment period the score was 0 p., which means excellent results, i.e. complete healing of the wounds. CONCLUSION: We believe that the application of PRP may become optimal therapy in the treatment of difficult to heal wounds around joints, bone, subject tendons, plantar surface of the foot, etc., as it opens new perspectives in the field of human tissue regeneration.

  8. Identification of Conserved and Species-Specific Functions of the Listeria monocytogenes PrsA2 Secretion Chaperone

    Science.gov (United States)

    Cahoon, Laty A.

    2015-01-01

    The Gram-positive bacterium Listeria monocytogenes is a facultative intracellular pathogen that relies on the regulated secretion and activity of a variety of proteins that sustain life within diverse environments. PrsA2 has recently been identified as a secreted peptidyl-prolyl cis/trans isomerase and chaperone that is dispensable for bacterial growth in broth culture but essential for L. monocytogenes virulence. Following host infection, PrsA2 contributes to the proper folding and activity of secreted proteins that are required for bacterial replication within the host cytosol and for bacterial spread to adjacent cells. PrsA2 is one member of a family of Gram-positive secretion chaperones that appear to play important roles in bacterial physiology; however, it is not known how these proteins recognize their substrate proteins or the degree to which their function is conserved across diverse Gram-positive species. We therefore examined PrsA proteins encoded by a variety of Gram-positive bacteria for functional complementation of L. monocytogenes mutants lacking prsA2. PrsA homologues encoded by Bacillus subtilis, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus mutans, Staphylococcus aureus, and Lactococcus lactis were examined for functional complementation of a variety of L. monocytogenes PrsA2-associated phenotypes central to L. monocytogenes pathogenesis and bacterial cell physiology. Our results indicate that while selected aspects of PrsA2 function are broadly conserved among diverse Gram-positive bacteria, PrsA2 exhibits unique specificity for L. monocytogenes target proteins required for pathogenesis. The L. monocytogenes PrsA2 chaperone thus appears evolutionarily optimized for virulence factor secretion within the host cell cytosol while still maintaining aspects of activity relevant to more general features of Gram-positive protein translocation. PMID:26216425

  9. Motif-grafted antibodies containing the replicative interface of cellular PrP are specific for PrPSc.

    Science.gov (United States)

    Moroncini, Gianluca; Kanu, Nnennaya; Solforosi, Laura; Abalos, Gil; Telling, Glenn C; Head, Mark; Ironside, James; Brockes, Jeremy P; Burton, Dennis R; Williamson, R Anthony

    2004-07-13

    Prion diseases are closely associated with the conversion of the cellular prion protein (PrPC) to an abnormal conformer (PrPSc) [Prusiner, S. B. (1998) Proc. Natl. Acad. Sci. USA 95, 13363-13383]. Monoclonal antibodies that bind epitopes comprising residues 96-104 and 133-158 of PrPC potently inhibit this process, presumably by preventing heterodimeric association of PrPC and PrPSc, and suggest that these regions of PrPC may be critical components of the PrPC-PrPSc replicative interface. We reasoned that transplanting PrP sequence corresponding to these regions into a suitable carrier molecule, such as an antibody, could impart specific recognition of disease-associated forms of PrP. To test this hypothesis, polypeptides containing PrP sequence between residues 89-112 or 136-158 were used to replace the extended heavy chain complementarity-determining region 3 of an IgG antibody specific for the envelope glycoprotein of HIV-1. Herein the resulting engineered PrP-IgGs are shown to bind specifically to infective fractions of PrP in mouse, human, and hamster prion-infected tissues, but not to PrPC, other cellular components, or the HIV-1 envelope. PrPSc reactivity was abolished when the sequence of the PrP 89-112 and 136-158 grafts was mutated, scrambled, or N-terminally truncated. Our findings suggest that residues within the 89-112 and 136-158 segments of PrPC are key components of one face of the PrPC-PrPSc complex. PrPSc-specific antibodies produced by the approach described may find widespread application in the study of prion biology and replication and in the detection of infectious prions in human and animal materials.

  10. CONTAMINATED PROBLEMATIC SKIN WOUNDS IN DIABETIC PATIENTS TREATED WITH AUTOLOGOUS PLATELET-RICH PLASMA (PRP: A case series study

    Directory of Open Access Journals (Sweden)

    Tsvetan Sokolov

    2016-03-01

    Full Text Available OBJECTIVE: To study the effect of platelet-rich plasma (PRP on contaminated problematic skin ulcers in patients with diabetes. MATERIAL AND METHODS: A total of 6 patients had been treated within the period from 2012 to 2014; they had various types of problematic wounds and diabetes type 2. Patients’ distribution by sex was as follows: 1 man and 5 women; mean age- 68 years. Ulcer types: acute (2 patients, hard-to-heal (2 patients and chronic (2 patients ulcers. The mean size of the skin and soft tissue defect was 9,5 cm2. Pathogenic microflora was isolated in 4 patients - S. aureus in three and Е. Coli in one. Based on a scheme developed by us, all cases were treated by administering platelet-rich plasma, derived by PRGF Endoret system. Follow-up period was within 4 – 6 months (4,5 on average. We used platelet rich plasma derived by PRGF Endoret system, applied on the wound bed on a weekly basis. RESULTS: Application of PRP allowed successful closure of all wounds. There were no complications associated with treatment of PRP. Epithelialization of the wound took 15 weeks on average for all patients. One patient presented with hyperkeratosis. Initial score of followed wounds, based on the scales are as follows: Total wound score – 10 p. Total anatomic score – 8 p. Total score – 15 p. at the initial stage. At the end of the treatment period scores were as follows - 0 p., which means excellent results CONCLUSION: We believe that the application of PRP may become optimal therapy in the treatment of contaminated problematic wounds in diabetic patients. PRP not only stimulates wound healing, but also has antimicrobial properties, which may contribute to the prevention of infections.

  11. Cloning, expression and crystallisation of SGT1 co-chaperone protein from Glaciozyma antarctica

    Science.gov (United States)

    Yusof, Nur Athirah; Bakar, Farah Diba Abu; Beddoe, Travis; Murad, Abdul Munir Abdul

    2013-11-01

    Studies on psycrophiles are now in the limelight of today's post genomic era as they fascinate the research and development industries. The discovery from Glaciozyma antarctica, an extreme cold adapted yeast from Antarctica shows promising future to provide cost effective natural sustainable energy and create wider understanding of the property that permits this organisms to adapt to extreme temperature downshift. In plants and yeast, studies show the interaction between SGT1 and HSP90 are essential for disease resistance and heat stress by activating a number of resistance proteins. Here we report for the first time cloning, expression and crystallization of the recombinant SGT1 protein of G. antarctica (rGa_SGT1), a highly conserved eukaryotic protein that interacts with the molecular chaperones HSP90 (heat shock protein 90) apparently associated in a role of co-chaperone that may play important role in cold adaptation. The sequence analysis of rGa_SGT1 revealed the presence of all the characteristic features of SGT1 protein. In this study, we present the outlines and results of protein structural study of G. antarctica SGT1 protein. We validate this approach by starting with cloning the target insert into Ligation Independent Cloning system proceeded with expression using E. coli system, and crystallisation of the target rGA_SGT1 protein. The work is still on going with the target subunit of the complex proteins yielded crystals. These results, still ongoing, open a platform for better understanding of the uniqueness of this crucial molecular machine function in cold adaptation.

  12. The mitochondrial chaperone protein TRAP1 mitigates α-Synuclein toxicity.

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    Erin K Butler

    2012-02-01

    Full Text Available Overexpression or mutation of α-Synuclein is associated with protein aggregation and interferes with a number of cellular processes, including mitochondrial integrity and function. We used a whole-genome screen in the fruit fly Drosophila melanogaster to search for novel genetic modifiers of human [A53T]α-Synuclein-induced neurotoxicity. Decreased expression of the mitochondrial chaperone protein tumor necrosis factor receptor associated protein-1 (TRAP1 was found to enhance age-dependent loss of fly head dopamine (DA and DA neuron number resulting from [A53T]α-Synuclein expression. In addition, decreased TRAP1 expression in [A53T]α-Synuclein-expressing flies resulted in enhanced loss of climbing ability and sensitivity to oxidative stress. Overexpression of human TRAP1 was able to rescue these phenotypes. Similarly, human TRAP1 overexpression in rat primary cortical neurons rescued [A53T]α-Synuclein-induced sensitivity to rotenone treatment. In human (nonneuronal cell lines, small interfering RNA directed against TRAP1 enhanced [A53T]α-Synuclein-induced sensitivity to oxidative stress treatment. [A53T]α-Synuclein directly interfered with mitochondrial function, as its expression reduced Complex I activity in HEK293 cells. These effects were blocked by TRAP1 overexpression. Moreover, TRAP1 was able to prevent alteration in mitochondrial morphology caused by [A53T]α-Synuclein overexpression in human SH-SY5Y cells. These results indicate that [A53T]α-Synuclein toxicity is intimately connected to mitochondrial dysfunction and that toxicity reduction in fly and rat primary neurons and human cell lines can be achieved using overexpression of the mitochondrial chaperone TRAP1. Interestingly, TRAP1 has previously been shown to be phosphorylated by the serine/threonine kinase PINK1, thus providing a potential link of PINK1 via TRAP1 to α-Synuclein.

  13. Bovine leukemia virus nucleocapsid protein is an efficient nucleic acid chaperone

    Energy Technology Data Exchange (ETDEWEB)

    Qualley, Dominic F., E-mail: dqualley@berry.edu; Sokolove, Victoria L.; Ross, James L.

    2015-03-13

    Nucleocapsid proteins (NCs) direct the rearrangement of nucleic acids to form the most thermodynamically stable structure, and facilitate many steps throughout the life cycle of retroviruses. NCs bind strongly to nucleic acids (NAs) and promote NA aggregation by virtue of their cationic nature; they also destabilize the NA duplex via highly structured zinc-binding motifs. Thus, they are considered to be NA chaperones. While most retroviral NCs are structurally similar, differences are observed both within and between retroviral genera. In this work, we compare the NA binding and chaperone activity of bovine leukemia virus (BLV) NC to that of two other retroviral NCs: human immunodeficiency virus type 1 (HIV-1) NC, which is structurally similar to BLV NC but from a different retrovirus genus, and human T-cell leukemia virus type 1 (HTLV-1) NC, which possesses several key structural differences from BLV NC but is from the same genus. Our data show that BLV and HIV-1 NCs bind to NAs with stronger affinity in relation to HTLV-1 NC, and that they also accelerate the annealing of complementary stem-loop structures to a greater extent. Analysis of kinetic parameters derived from the annealing data suggests that while all three NCs stimulate annealing by a two-step mechanism as previously reported, the relative contributions of each step to the overall annealing equilibrium are conserved between BLV and HIV-1 NCs but are different for HTLV-1 NC. It is concluded that while BLV and HTLV-1 belong to the same genus of retroviruses, processes that rely on NC may not be directly comparable. - Highlights: • BLV NC binds strongly to DNA and RNA. • BLV NC promotes mini-TAR annealing as well as HIV-1 NC. • Annealing kinetics suggest a low degree of similarity between BLV NC and HTLV-1 NC.

  14. A New Glucocerebrosidase Chaperone Reduces α-Synuclein and Glycolipid Levels in iPSC-Derived Dopaminergic Neurons from Patients with Gaucher Disease and Parkinsonism.

    Science.gov (United States)

    Aflaki, Elma; Borger, Daniel K; Moaven, Nima; Stubblefield, Barbara K; Rogers, Steven A; Patnaik, Samarjit; Schoenen, Frank J; Westbroek, Wendy; Zheng, Wei; Sullivan, Patricia; Fujiwara, Hideji; Sidhu, Rohini; Khaliq, Zayd M; Lopez, Grisel J; Goldstein, David S; Ory, Daniel S; Marugan, Juan; Sidransky, Ellen

    2016-07-13

    Among the known genetic risk factors for Parkinson disease, mutations in GBA1, the gene responsible for the lysosomal disorder Gaucher disease, are the most common. This genetic link has directed attention to the role of the lysosome in the pathogenesis of parkinsonism. To study how glucocerebrosidase impacts parkinsonism and to evaluate new therapeutics, we generated induced human pluripotent stem cells from four patients with Type 1 (non-neuronopathic) Gaucher disease, two with and two without parkinsonism, and one patient with Type 2 (acute neuronopathic) Gaucher disease, and differentiated them into macrophages and dopaminergic neurons. These cells exhibited decreased glucocerebrosidase activity and stored the glycolipid substrates glucosylceramide and glucosylsphingosine, demonstrating their similarity to patients with Gaucher disease. Dopaminergic neurons from patients with Type 2 and Type 1 Gaucher disease with parkinsonism had reduced dopamine storage and dopamine transporter reuptake. Levels of α-synuclein, a protein present as aggregates in Parkinson disease and related synucleinopathies, were selectively elevated in neurons from the patients with parkinsonism or Type 2 Gaucher disease. The cells were then treated with NCGC607, a small-molecule noninhibitory chaperone of glucocerebrosidase identified by high-throughput screening and medicinal chemistry structure optimization. This compound successfully chaperoned the mutant enzyme, restored glucocerebrosidase activity and protein levels, and reduced glycolipid storage in both iPSC-derived macrophages and dopaminergic neurons, indicating its potential for treating neuronopathic Gaucher disease. In addition, NCGC607 reduced α-synuclein levels in dopaminergic neurons from the patients with parkinsonism, suggesting that noninhibitory small-molecule chaperones of glucocerebrosidase may prove useful for the treatment of Parkinson disease. Because GBA1 mutations are the most common genetic risk factor for

  15. In vivo functional expression of a screened P. aeruginosa chaperone-dependent lipase in E. coli

    Directory of Open Access Journals (Sweden)

    Wu Xiangping

    2012-09-01

    Full Text Available Abstract Background Microbial lipases particularly Pseudomonas lipases are widely used for biotechnological applications. It is a meaningful work to design experiments to obtain high-level active lipase. There is a limiting factor for functional overexpression of the Pseudomonas lipase that a chaperone is necessary for effective folding. As previously reported, several methods had been used to resolve the problem. In this work, the lipase (LipA and its chaperone (LipB from a screened strain named AB which belongs to Pseudomonas aeruginosa were overexpressed in E. coli with two dual expression plasmid systems to enhance the production of the active lipase LipA without in vitro refolding process. Results In this work, we screened a lipase-produced strain named AB through the screening procedure, which was identified as P. aeruginosa on the basis of 16S rDNA. Genomic DNA obtained from the strain was used to isolate the gene lipA (936 bp and lipase specific foldase gene lipB (1023 bp. One single expression plasmid system E. coli BL21/pET28a-lipAB and two dual expression plasmid systems E. coli BL21/pETDuet-lipA-lipB and E. coli BL21/pACYCDuet-lipA-lipB were successfully constructed. The lipase activities of the three expression systems were compared to choose the optimal expression method. Under the same cultured condition, the activities of the lipases expressed by E. coli BL21/pET28a-lipAB and E. coli BL21/pETDuet-lipA-lipB were 1300 U/L and 3200 U/L, respectively, while the activity of the lipase expressed by E. coli BL21/pACYCDuet-lipA-lipB was up to 8500 U/L. The lipase LipA had an optimal temperature of 30°C and an optimal pH of 9 with a strong pH tolerance. The active LipA could catalyze the reaction between fatty alcohols and fatty acids to generate fatty acid alkyl esters, which meant that LipA was able to catalyze esterification reaction. The most suitable fatty acid and alcohol substrates for esterification were octylic acid and hexanol

  16. Proteotoxicity is not the reason for the dependence of cancer cells on the major chaperone Hsp70.

    Science.gov (United States)

    Colvin, Teresa A; Gabai, Vladimir L; Sherman, Michael Y

    2014-01-01

    Several years ago a hypothesis was proposed that the survival of cancer cells depend on elevated expression of molecular chaperones because these cells are prone to proteotoxic stress. A critical prediction of this hypothesis is that depletion of chaperones in cancer cells should lead to proteotoxicity. Here, using the major chaperone Hsp70 as example, we demonstrate that its depletion does not trigger proteotoxic stress, thus refuting the model. Accordingly, other functions of chaperones, e.g., their role in cell signaling, might define the requirements for chaperones in cancer cells, which is critical for rational targeting Hsp70 in cancer treatment.

  17. Small kinetochore associated protein (SKAP promotes UV-induced cell apoptosis through negatively regulating pre-mRNA processing factor 19 (Prp19.

    Directory of Open Access Journals (Sweden)

    Shan Lu

    Full Text Available Apoptosis is a regulated cellular suicide program that is critical for the development and maintenance of healthy tissues. Previous studies have shown that small kinetochore associated protein (SKAP cooperates with kinetochore and mitotic spindle proteins to regulate mitosis. However, the role of SKAP in apoptosis has not been investigated. We have identified a new interaction involving SKAP, and we propose a mechanism through which SKAP regulates cell apoptosis. Our experiments demonstrate that both overexpression and knockdown of SKAP sensitize cells to UV-induced apoptosis. Further study has revealed that SKAP interacts with Pre-mRNA processing Factor 19 (Prp19. We find that UV-induced apoptosis can be inhibited by ectopic expression of Prp19, whereas silencing Prp19 has the opposite effect. Additionally, SKAP negatively regulates the protein levels of Prp19, whereas Prp19 does not alter SKAP expression. Finally, rescue experiments demonstrate that the pro-apoptotic role of SKAP is executed through Prp19. Taken together, these findings suggest that SKAP promotes UV-induced cell apoptosis by negatively regulating the anti-apoptotic protein Prp19.

  18. Antarctic krill 454 pyrosequencing reveals chaperone and stress transcriptome.

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    Melody S Clark

    Full Text Available BACKGROUND: The Antarctic krill Euphausia superba is a keystone species in the Antarctic food chain. Not only is it a significant grazer of phytoplankton, but it is also a major food item for charismatic megafauna such as whales and seals and an important Southern Ocean fisheries crop. Ecological data suggest that this species is being affected by climate change and this will have considerable consequences for the balance of the Southern Ocean ecosystem. Hence, understanding how this organism functions is a priority area and will provide fundamental data for life history studies, energy budget calculations and food web models. METHODOLOGY/PRINCIPAL FINDINGS: The assembly of the 454 transcriptome of E. superba resulted in 22,177 contigs with an average size of 492bp (ranging between 137 and 8515bp. In depth analysis of the data revealed an extensive catalogue of the cellular chaperone systems and the major antioxidant proteins. Full length sequences were characterised for the chaperones HSP70, HSP90 and the super-oxide dismutase antioxidants, with the discovery of potentially novel duplications of these genes. The sequence data contained 41,470 microsatellites and 17,776 Single Nucleotide Polymorphisms (SNPs/INDELS, providing a resource for population and also gene function studies. CONCLUSIONS: This paper details the first 454 generated data for a pelagic Antarctic species or any pelagic crustacean globally. The classical "stress proteins", such as HSP70, HSP90, ferritin and GST were all highly expressed. These genes were shown to be over expressed in the transcriptomes of Antarctic notothenioid fish and hypothesized as adaptations to living in the cold, with the associated problems of decreased protein folding efficiency and increased vulnerability to damage by reactive oxygen species. Hence, these data will provide a major resource for future physiological work on krill, but in particular a suite of "stress" genes for studies understanding

  19. One out of four: HspL but no other small heat shock protein of Agrobacterium tumefaciens acts as efficient virulence-promoting VirB8 chaperone.

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    Yun-Long Tsai

    Full Text Available Alpha-crystallin-type small heat shock proteins (sHsps are ubiquitously distributed in most eukaryotes and prokaryotes. Four sHsp genes named hspL, hspC, hspAT1, and hspAT2 were identified in Agrobacterium tumefaciens, a plant pathogenic bacterium capable of unique interkingdom DNA transfer via type IV secretion system (T4SS. HspL is highly expressed in virulence-induced growth condition and functions as a VirB8 chaperone to promote T4SS-mediated DNA transfer. Here, we used genetic and biochemical approaches to investigate the involvement of the other three sHsps in T4SS and discovered the molecular basis underlying the dominant function of HspL in promoting T4SS function. While single deletion of hspL but no other sHsp gene reduced T4SS-mediated DNA transfer and tumorigenesis efficiency, additional deletion of other sHsp genes in the hspL deletion background caused synergistic effects in the virulence phenotypes. This is correlated with the high induction of hspL and only modest increase of hspC, hspAT1, and hspAT2 at their mRNA and protein abundance in virulence-induced growth condition. Interestingly, overexpression of any single sHsp gene alone in the quadruple mutant caused increased T4SS-mediated DNA transfer and tumorigenesis. Thermal aggregation protecting assays in vitro indicated that all four sHsps exhibit chaperone activity for the model substrate citrate synthase but only HspL functions as efficient chaperone for VirB8. The higher VirB8 chaperone activity of HspL was also demonstrated in vivo, in which lower amounts of HspL than other sHsps were sufficient in maintaining VirB8 homeostasis in A. tumefaciens. Domain swapping between HspL and HspAT2 indicated that N-terminal, central alpha-crystallin, and C-terminal domains of HspL all contribute to HspL function as an efficient VirB8 chaperone. Taken together, we suggest that the dominant role of HspL in promoting T4SS function is based on its higher expression in virulence

  20. A fully liquid DTaP-IPV-HB-PRP-T hexavalent vaccine for primary and booster vaccination of healthy Turkish infants and toddlers

    Science.gov (United States)

    Ceyhan, Mehmet; Yıldırım, İnci; Tezer, Hasan; Devrim, İlker; Feroldi, Emmanuel

    2017-08-23

    Background/aim: Immunogenicity and safety of a primary series of a fully liquid, hexavalent DTaP-IPV-HB-PRP-T vaccine given at 2, 3, and 4 months of age compared to licensed comparators and a DTaP-IPV-HB-PRP-T booster at 15?18 months were evaluated. Materials and methods: This was a Phase III, randomized, open-label trial. Primary series (no hepatitis B [HB] at birth) of DTaP-IPV-HB-PRP-T (N = 155) (group 1) or licensed control vaccines (DTaP-IPV//PRP-T and standalone HB: N = 155) (group 2) and DTaP-IPV-HB-PRP-T booster were administered. Noninferiority was evaluated 1 month postprimary series for anti-HB seroprotection (SP). All other analyses were descriptive. Safety was assessed from parental reports. Results: Postprimary series noninferiority of anti-HB ≥ 10 mIU/mL was demonstrated for the DTaP-IPV-HB-PRP-T vaccine (94.0%) compared to the licensed control (96.1%). Postprimary series primary SP and seroconversion (SC) rates were high and similar for both groups. Antibody persistence (prebooster) was high for each antigen and similar between groups except for HB, which was lower for DTaP-IPV-HB-PRP-T than for standalone HB. For each antigen except HB, DTaP-IPV-HB-PRP-T booster responses were high and similar in each group. Safety was good for primary and booster series and similar between groups. Conclusion: The DTaP-IPV-HB-PRP-T vaccine is immunogenic and safe when administered in a challenging primary series schedule without HB vaccination at birth.

  1. Investigation of modified platelet-rich plasma (mPRP) in promoting the proliferation and differentiation of dental pulp stem cells from deciduous teeth

    OpenAIRE

    Wen, J.; Li, H T; Li, S H; LI, X.; Duan, J. M.

    2016-01-01

    Stem cells from human exfoliated deciduous teeth (SHEDs) have great potential to treat various dental-related diseases in regenerative medicine. They are usually maintained with 10% fetal bovine serum (FBS) in vitro. Modified platelet-rich plasma (mPRP) would be a safe alternative to 10% FBS during SHEDs culture. Therefore, our study aimed to compare the proliferation and differentiation of SHEDs cultured in mPRP and FBS medium to explore an optimal concentration of mPRP for SHEDs maintenance...

  2. Amidation and structure relaxation abolish the neurotoxicity of the prion peptide PrP106-126 in vivo and in vitro

    DEFF Research Database (Denmark)

    Bergstrøm, Linda Alice; Hvass, Henriette Cordes; Zsurger, N.

    2005-01-01

    One of the major pathological hallmarks of transmissible spongiform encephalopathies (TSEs) is the accumulation of a pathogenic (scrapie) isoform (PrPSc) of the cellular prion protein (PrPC) primarily in the central nervous system. The synthetic prion peptide PrP106-126 shares many characteristics...... with PrPSc in that it shows PrPC-dependent neurotoxicity both in vivo and in vitro. Moreover, PrP106-126 in vitro neurotoxicity has been closely associated with the ability to form fibrils. Here, we studied the in vivo neurotoxicity of molecular variants of PrP106-126 toward retinal neurons using...

  3. Rôle du domaine N-terminal de la PrP dans la pathogenèse des maladies à prions

    OpenAIRE

    Erlich, Paul

    2009-01-01

    The role of the N-terminal (N-ter) domain of PrP protein in the conversion of PrPc into an infectious isoform PrPSc is poorly understood. The objective of my thesis was to create a synthetic prion composed of the N-ter domain of PrP and the Doppel protein to get an insight in the involvement of this PrP domain in the aggregation mechanisms and the pathogenesis of prion diseases. Three PrP/Dpl chimeric recombinant proteins were expressed, purified and aggregated in vitro into oligomers. These ...

  4. Effect of Platelet-Rich Plasma (PRP) versus Autologous Whole Blood on Pain and Function Improvement in Tennis Elbow: A Randomized Clinical Trial

    OpenAIRE

    Raeissadat, Seyed Ahmad; Sedighipour, Leyla; Rayegani, Seyed Mansoor; Bahrami, Mohammad Hasan; Bayat, Masume; Rahimi, Rosa

    2014-01-01

    Background. Autologous whole blood and platelet-rich plasma (PRP) have been both suggested to treat chronic tennis elbow. The aim of the present study was to compare the effects of PRP versus autologous whole blood local injection in chronic tennis elbow. Methods. Forty patients with tennis elbow were randomly divided into 2 groups. Group 1 was treated with a single injection of 2 mL of autologous PRP and group 2 with 2 mL of autologous blood. Tennis elbow strap, stretching, and strengthening...

  5. Decreased hernia recurrence using autologous platelet-rich plasma (PRP) with Strattice™ mesh in a rodent ventral hernia model.

    Science.gov (United States)

    Van Eps, Jeffrey; Fernandez-Moure, Joseph; Cabrera, Fernando; Wang, Xin; Karim, Azim; Corradetti, Bruna; Chan, Paige; Dunkin, Brian; Tasciotti, Ennio; Weiner, Bradley; Ellsworth, Warren

    2016-08-01

    Recurrence after ventral hernia repair (VHR) remains a multifactorial problem still plaguing surgeons today. Some of the many contributing factors include mechanical strain, poor tissue-mesh integration, and degradation of matrices. The high recurrence rate witnessed with the use of acellular dermal matrices (ADM) for definitive hernia repair has reduced their use largely to bridging repair and breast reconstruction. Modalities that improve classic cellular metrics of successful VHR could theoretically result in improved rates of hernia recurrence; autologous platelet-rich plasma (PRP) may represent one such tool, but has been underinvestigated for this purpose. Lewis rats (32) had chronic ventral hernias created surgically and then repaired with Strattice™ mesh alone (control) or mesh + autologous PRP. Samples were harvested at 3 and 6 months postoperatively and compared for gross, histologic, and molecular outcomes of: neovascularization, tissue incorporation, peritoneal adhesions, hernia recurrence, and residual mesh thickness. Compared to control at 3 months postoperatively, PRP-treated rats displayed significantly more neovascularization of implanted mesh and considerable upregulation of both angiogenic genes (vEGF 2.73-fold, vWF 2.21-fold) and myofibroblastic genes (αSMA 9.68-fold, FSP-1 3.61-fold, Col1a1 3.32-fold, Col31a1 3.29-fold). Histologically, they also showed enhanced tissue deposition/ingrowth and diminished chronic immune cell infiltration. Peritoneal adhesions were less severe at both 3 (1.88 vs. 2.94) and 6 months (1.63 vs. 2.75) by Modified Hopkins Adhesion Scoring. PRP-treated rats experienced decreased hernia recurrence at 6 months (0/10 vs. 7/10) and had significantly improved ADM preservation as evidenced by quantification of residual mesh thickness. PRP is an autologous source of pro-regenerative growth factors and chemokines uniquely suited to soft tissue wound healing. When applied to a model of chronic VHR, it incites enhanced

  6. Alda-1 is an agonist and chemical chaperone for the common human aldehyde dehydrogenase 2 variant

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Miller, Samantha; Younus, Hina; Vanam, Ram; Chen, Che-Hong; Mochly-Rosen, Daria; Hurley, Thomas D. (Indiana-Med); (Stanford-MED)

    2010-04-19

    In approximately one billion people, a point mutation inactivates a key detoxifying enzyme, aldehyde dehydrogenase (ALDH2). This mitochondrial enzyme metabolizes toxic biogenic and environmental aldehydes, including the endogenously produced 4-hydroxynonenal (4HNE) and the environmental pollutant acrolein, and also bioactivates nitroglycerin. ALDH2 is best known, however, for its role in ethanol metabolism. The accumulation of acetaldehyde following the consumption of even a single alcoholic beverage leads to the Asian alcohol-induced flushing syndrome in ALDH2*2 homozygotes. The ALDH2*2 allele is semidominant, and heterozygotic individuals show a similar but less severe phenotype. We recently identified a small molecule, Alda-1, that activates wild-type ALDH2 and restores near-wild-type activity to ALDH2*2. The structures of Alda-1 bound to ALDH2 and ALDH2*2 reveal how Alda-1 activates the wild-type enzyme and how it restores the activity of ALDH2*2 by acting as a structural chaperone.

  7. Induced prion protein controls immune-activated retroviruses in the mouse spleen.

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    Marius Lötscher

    Full Text Available The prion protein (PrP is crucially involved in transmissible spongiform encephalopathies (TSE, but neither its exact role in disease nor its physiological function are known. Here we show for mice, using histological, immunochemical and PCR-based methods, that stimulation of innate resistance was followed by appearance of numerous endogenous retroviruses and ensuing PrP up-regulation in germinal centers of the spleen. Subsequently, the activated retroviruses disappeared in a PrP-dependent manner. Our results reveal the regular involvement of endogenous retroviruses in murine immune responses and provide evidence for an essential function of PrP in the control of the retroviral activity. The interaction between PrP and ubiquitous endogenous retroviruses may allow new interpretations of TSE pathophysiology and explain the evolutionary conservation of PrP.

  8. Thiol-based copper handling by the copper chaperone Atox1.

    Science.gov (United States)

    Hatori, Yuta; Inouye, Sachiye; Akagi, Reiko

    2017-04-01

    Human antioxidant protein 1 (Atox1) plays a crucial role in cellular copper homeostasis. Atox1 captures cytosolic copper for subsequent transfer to copper pumps in trans Golgi network, thereby facilitating copper supply to various copper-dependent oxidereductases matured within the secretory vesicles. Atox1 and other copper chaperones handle cytosolic copper using Cys thiols which are ideal ligands for coordinating Cu(I). Recent studies demonstrated reversible oxidation of these Cys residues in copper chaperones, linking cellular redox state to copper homeostasis. Highlighted in this review are unique redox properties of Atox1 and other copper chaperones. Also, summarized are the redox nodes in the cytosol which potentially play dominant roles in the redox regulation of copper chaperones. © 2016 IUBMB Life, 69(4):246-254, 2017. © 2017 International Union of Biochemistry and Molecular Biology.

  9. Substitutions of PrP N-terminal histidine residues modulate scrapie disease pathogenesis and incubation time in transgenic mice.

    Directory of Open Access Journals (Sweden)

    Sabina Eigenbrod

    Full Text Available Prion diseases have been linked to impaired copper homeostasis and copper induced-oxidative damage to the brain. Divalent metal ions, such as Cu2+ and Zn2+, bind to cellular prion protein (PrPC at octapeptide repeat (OR and non-OR sites within the N-terminal half of the protein but information on the impact of such binding on conversion to the misfolded isoform often derives from studies using either OR and non-OR peptides or bacterially-expressed recombinant PrP. Here we created new transgenic mouse lines expressing PrP with disrupted copper binding sites within all four histidine-containing OR's (sites 1-4, H60G, H68G, H76G, H84G, "TetraH>G" allele or at site 5 (composed of residues His-95 and His-110; "H95G" allele and monitored the formation of misfolded PrP in vivo. Novel transgenic mice expressing PrP(TetraH>G at levels comparable to wild-type (wt controls were susceptible to mouse-adapted scrapie strain RML but showed significantly prolonged incubation times. In contrast, amino acid replacement at residue 95 accelerated disease progression in corresponding PrP(H95G mice. Neuropathological lesions in terminally ill transgenic mice were similar to scrapie-infected wt controls, but less severe. The pattern of PrPSc deposition, however, was not synaptic as seen in wt animals, but instead dense globular plaque-like accumulations of PrPSc in TgPrP(TetraH>G mice and diffuse PrPSc deposition in (TgPrP(H95G mice, were observed throughout all brain sections. We conclude that OR and site 5 histidine substitutions have divergent phenotypic impacts and that cis interactions between the OR region and the site 5 region modulate pathogenic outcomes by affecting the PrP globular domain.

  10. Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF).

    Science.gov (United States)

    Dohan Ehrenfest, David M; Rasmusson, Lars; Albrektsson, Tomas

    2009-03-01

    The topical use of platelet concentrates is recent and its efficiency remains controversial. Several techniques for platelet concentrates are available; however, their applications have been confusing because each method leads to a different product with different biology and potential uses. Here, we present classification of the different platelet concentrates into four categories, depending on their leucocyte and fibrin content: pure platelet-rich plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; leucocyte- and platelet-rich plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan or GPS PRP; pure plaletet-rich fibrin (P-PRF), such as Fibrinet; and leucocyte- and platelet-rich fibrin (L-PRF), such as Choukroun's PRF. This classification should help to elucidate successes and failures that have occurred so far, as well as providing an objective approach for the further development of these techniques.

  11. In vitro immunological and biological evaluations of the angiogenic potential of platelet-rich fibrin preparations: a standardized comparison with PRP preparations

    National Research Council Canada - National Science Library

    Kobayashi, Mito; Kawase, Tomoyuki; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

    2015-01-01

    Platelet-rich fibrin (PRF), a platelet-rich plasma (PRP) derivative mainly composed of fibrin networks, has been increasingly demonstrated to be effective in wound healing in clinical and pre-clinical animal studies...

  12. The Deinococcus radiodurans DR1245 Protein, a DdrB Partner Homologous to YbjN Proteins and Reminiscent of Type III Secretion System Chaperones

    Science.gov (United States)

    Bouthier-de-la-Tour, Claire; Coureux, Pierre-Damien; Ithurbide, Solenne; Vannier, Françoise; Guerin, Philippe P.; Dulberger, Charles L.; Satyshur, Kenneth A.; Keck, James L.; Armengaud, Jean; Cox, Michael M.; Sommer, Suzanne

    2013-01-01

    The bacterium Deinococcus radiodurans exhibits an extreme resistance to ionizing radiation. A small subset of Deinococcus genus-specific genes were shown to be up-regulated upon exposure to ionizing radiation and to play a role in genome reconstitution. These genes include an SSB-like protein called DdrB. Here, we identified a novel protein encoded by the dr1245 gene as an interacting partner of DdrB. A strain devoid of the DR1245 protein is impaired in growth, exhibiting a generation time approximately threefold that of the wild type strain while radioresistance is not affected. We determined the three-dimensional structure of DR1245, revealing a relationship with type III secretion system chaperones and YbjN family proteins. Thus, DR1245 may display some chaperone activity towards DdrB and possibly other substrates. PMID:23441204

  13. Rapid preparation of (3R,4S,5R) polyhydroxylated pyrrolidine-based libraries to discover a pharmacological chaperone for treatment of Fabry disease.

    Science.gov (United States)

    Cheng, Wei-Chieh; Wang, Jen-Hon; Yun, Wen-Yi; Li, Huang-Yi; Hu, Jia-Ming

    2017-01-27

    The rapid discovery of a pharmacological chaperone toward human α-Gal A for the treatment of Fabry disease is described. Two polyhydroxylated pyrrolidines with the (3R,4S,5R) configuration pattern underwent rapid substituent diversity by conjugating the primary aminomethyl moiety of each with a variety of carboxylic acids to generate two libraries (2 × 60 members). Our bioevaluation results showed one member with the (2R,3R,4S,5R) configuration pattern and bearing a 5-cyclohexylpentanoyl group as a substituent moiety possessed sufficient chaperoning capability to rescue α-Gal A activity in the lymphocyte of the N215S Fabry patient-derived cell line and other α-Gal A mutants in COS7 cells. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. The Deinococcus radiodurans DR1245 Protein, a DdrB Partner Homologous to YbjN Proteins and Reminiscent of Type III Secretion System Chaperones

    Energy Technology Data Exchange (ETDEWEB)

    Norais, Cédric [Univ. of Wisconsin, Madison, WI (United States); Ecole Polytechnic, Paaiseau (France); Servant, Pascale [Univ. of Paris-Sud, Orsay (France); National Center of Scientific Research, Orsay (France); Bouthier-de-la-Tour, Claire [Univ. of Paris-Sud, Orsay (France); National Center of Scientific Research, Orsay (France); Coureux, Pierre-Damien [Ecole Polytechnic, Paaiseau (France); Ithurbide, Solenne [Univ. of Paris-Sud, Orsay (France); National Center of Scientific Research, Orsay (France); Vannier, Françoise [Univ. of Paris-Sud, Orsay (France); National Center of Scientific Research, Orsay (France); Guerin, Philippe P. [French Alternatives Energy Commission (France); Dulberger, Charles L. [Univ. of Wisconsin, Madison, WI (United States); Satyshur, Kenneth A. [Univ. of Wisconsin, Madison, WI (United States); Keck, James L. [Univ. of Wisconsin, Madison, WI (United States); Armengaud, Jean [French Alternatives Energy Commission (France); Cox, Michael M. [Univ. of Wisconsin, Madison, WI (United States); Sommer, Suzanne [Univ. of Paris-Sud, Orsay (France); National Center of Scientific Research, Orsay (France)

    2013-02-18

    The bacterium Deinococcus radiodurans exhibits an extreme resistance to ionizing radiation. A small subset of Deinococcus genus-specific genes were shown to be up-regulated upon exposure to ionizing radiation and to play a role in genome reconstitution. These genes include an SSB-like protein called DdrB. Here, we identified a novel protein encoded by the dr1245gene as an interacting partner of DdrB. A strain devoid of the DR1245 protein is impaired in growth, exhibiting a generation time approximately threefold that of the wild type strain while radioresistance is not affected. We determined the three-dimensional structure of DR1245, revealing a relationship with type III secretion system chaperones and YbjN family proteins. Thus, DR1245 may display some chaperone activity towards DdrB and possibly other substrates.

  15. The Deinococcus radiodurans DR1245 protein, a DdrB partner homologous to YbjN proteins and reminiscent of type III secretion system chaperones.

    Directory of Open Access Journals (Sweden)

    Cédric Norais

    Full Text Available The bacterium Deinococcus radiodurans exhibits an extreme resistance to ionizing radiation. A small subset of Deinococcus genus-specific genes were shown to be up-regulated upon exposure to ionizing radiation and to play a role in genome reconstitution. These genes include an SSB-like protein called DdrB. Here, we identified a novel protein encoded by the dr1245 gene as an interacting partner of DdrB. A strain devoid of the DR1245 protein is impaired in growth, exhibiting a generation time approximately threefold that of the wild type strain while radioresistance is not affected. We determined the three-dimensional structure of DR1245, revealing a relationship with type III secretion system chaperones and YbjN family proteins. Thus, DR1245 may display some chaperone activity towards DdrB and possibly other substrates.

  16. Behavior of Gingival Fibroblasts on Titanium Implant Surfaces in Combination with either Injectable-PRF or PRP

    Directory of Open Access Journals (Sweden)

    Xuzhu Wang

    2017-02-01

    Full Text Available Various strategies have been employed to speed tissue regeneration using bioactive molecules. Interestingly, platelet concentrates derived from a patient’s own blood have been utilized as a regenerative strategy in recent years. In the present study, a novel liquid platelet formulation prepared without the use of anti-coagulants (injectable-platelet-rich fibrin, i-PRF was compared to standard platelet-rich plasma (PRP with gingival fibroblasts cultured on smooth and roughened titanium implant surfaces. Standard PRP and i-PRF (centrifuged at 700 rpm (60× g for 3 min were compared by assays for fibroblast biocompatibility, migration, adhesion, proliferation, as well as expression of platelet-derived growth factor (PDGF, transforming growth factor-β (TGF-β, collagen1 (COL1 and fibronectin (FN. The results demonstrate that i-PRF induced significantly higher cell migration, as well as higher messenger RNA (mRNA levels of PDGF, TGF-β, collagen1 and fibronectin when compared to PRP. Furthermore, collagen1 synthesis was highest in the i-PRF group. These findings demonstrate that liquid platelet concentrates can be formulated without the use of anticoagulants and present much translational potential for future research. Future animal and clinical trials are now necessary to further investigate the potential of utilizing i-PRF for soft tissue regenerative protocols in combination with various biomaterials.

  17. Amyloid-β oligomers are sequestered by both intracellular and extracellular chaperones.

    Science.gov (United States)

    Narayan, Priyanka; Meehan, Sarah; Carver, John A; Wilson, Mark R; Dobson, Christopher M; Klenerman, David

    2012-11-20

    The aberrant aggregation of the amyloid-β peptide into β-sheet rich, fibrillar structures proceeds via a heterogeneous ensemble of oligomeric intermediates that have been associated with neurotoxicity in Alzheimer's disease (AD). Of particular interest in this context are the mechanisms by which molecular chaperones, part of the primary biological defenses against protein misfolding, influence Aβ aggregation. We have used single-molecule fluorescence techniques to compare the interactions between distinct aggregation states (monomers, oligomers, and amyloid fibrils) of the AD-associated amyloid-β(1-40) peptide, and two molecular chaperones, both of which are upregulated in the brains of patients with AD and have been found colocalized with Aβ in senile plaques. One of the chaperones, αB-crystallin, is primarily found inside cells, while the other, clusterin, is predominantly located in the extracellular environment. We find that both chaperones bind to misfolded oligomeric species and form long-lived complexes, thereby preventing both their further growth into fibrils and their dissociation. From these studies, we conclude that these chaperones have a common mechanism of action based on sequestering Aβ oligomers. This conclusion suggests that these chaperones, both of which are ATP-independent, are able to inhibit potentially pathogenic Aβ oligomer-associated processes whether they occur in the extracellular or intracellular environment.

  18. A fully liquid DTaP-IPV-Hep B-PRP-T hexavalent vaccine for primary and booster vaccination of healthy Mexican children.

    Science.gov (United States)

    Aquino, Amalia Guadalupe Becerra; Brito, Maricruz Gutiérrez; Doniz, Carlos E Aranza; Herrera, Juan Francisco Galán; Macias, Mercedes; Zambrano, Betzana; Plennevaux, Eric; Santos-Lima, Eduardo

    2012-10-05

    To evaluate an investigational, fully liquid hexavalent diphtheria-tetanus-acellular pertussis-inactivated poliovirus-hepatitis B-Haemophilus influenzae type b (DTaP-IPV-Hep B-PRP-T: Hexaxim™) vaccine for primary and booster vaccination of healthy children in Mexico. Infants (N=1189) were randomized to receive one of three lots of the DTaP-IPV-Hep B-PRP-T vaccine or a licensed hexavalent control vaccine (Infanrix™ hexa) for primary vaccination at 2, 4 and 6 months. All participants who completed the primary series and agreed to participate in the booster part of the study received a dose of the investigational vaccine at 15-18 months of age. Validated serological assays and parental reports were used to assess immunogenicity and safety, respectively. Post-primary vaccination, ≥95.8% of participants in both the DTaP-IPV-Hep B-PRP-T and control groups were seroprotected (SP) against diphtheria, tetanus, poliovirus, hepatitis B and PRP, or had seroconverted (SC) to the pertussis toxin (PT) and filamentous hemagglutinin (FHA) pertussis antigens. The SP/SC rates induced by the three DTaP-IPV-Hep B-PRP-T lots were equivalent. No differences in SP/SC rates were observed between the pooled lots of investigational vaccine and the control vaccine. Antibody persistence at 15-18 months was comparable between groups, with strong increases in all antibody concentrations post-DTaP-IPV-Hep B-PRP-T booster. Both vaccines were well tolerated for primary vaccination, as was the booster dose of DTaP-IPV-Hep B-PRP-T. These study findings confirm the suitability of the combined, fully liquid DTaP-IPV-Hep B-PRP-T vaccine for inclusion in routine childhood vaccination schedules. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Universal Stress Protein exhibits a redox-dependent chaperone function in Arabidopsis and enhances plant tolerance to heat shock and oxidative stress

    Directory of Open Access Journals (Sweden)

    Jung eYoung Jun

    2015-12-01

    Full Text Available Although a wide range of physiological information on Universal Stress Proteins (USPs is available from many organisms, their biochemical and molecular functions remain unidentified. The biochemical function of AtUSP (At3g53990 from Arabidopsis thaliana was therefore investigated. Plants over-expressing AtUSP showed a strong resistance to heat shock and oxidative stress, compared with wild-type and Atusp knock-out plants, confirming the crucial role of AtUSP in stress tolerance. AtUSP was present in a variety of structures including monomers, dimers, trimers, and oligomeric complexes, and switched in response to external stresses from low molecular weight (LMW species to high molecular weight (HMW complexes. AtUSP exhibited a strong chaperone function under stress conditions in particular, and this activity was significantly increased by heat treatment. Chaperone activity of AtUSP was critically regulated by the redox status of cells and accompanied by structural changes to the protein. Over-expression of AtUSP conferred a strong tolerance to heat shock and oxidative stress upon Arabidopsis, primarily via its chaperone function.

  20. Regulation of Rvb1/Rvb2 by a Domain within the INO80 Chromatin Remodeling Complex Implicates the Yeast Rvbs as Protein Assembly Chaperones

    Directory of Open Access Journals (Sweden)

    Coral Y. Zhou

    2017-06-01

    Full Text Available The hexameric AAA+ ATPases Rvb1 and Rvb2 (Rvbs are essential for diverse processes ranging from metabolic signaling to chromatin remodeling, but their functions are unknown. While originally thought to act as helicases, recent proposals suggest that Rvbs act as protein assembly chaperones. However, experimental evidence for chaperone-like behavior is lacking. Here, we identify a potent protein activator of the Rvbs, a domain in the Ino80 ATPase subunit of the INO80 chromatin-remodeling complex, termed Ino80INS. Ino80INS stimulates Rvbs’ ATPase activity by 16-fold while concomitantly promoting their dodecamerization. Using mass spectrometry, cryo-EM, and integrative modeling, we find that Ino80INS binds asymmetrically along the dodecamerization interface, resulting in a conformationally flexible dodecamer that collapses into hexamers upon ATP addition. Our results demonstrate the chaperone-like potential of Rvb1/Rvb2 and suggest a model where binding of multiple clients such as Ino80 stimulates ATP-driven cycling between hexamers and dodecamers, providing iterative opportunities for correct subunit assembly.

  1. RPS3a over-expressed in HBV-associated hepatocellular carcinoma enhances the HBx-induced NF-κB signaling via its novel chaperoning function.

    Directory of Open Access Journals (Sweden)

    Keo-Heun Lim

    Full Text Available Hepatitis B virus (HBV infection is one of the major causes of hepatocellular carcinoma (HCC development. Hepatitis B virus X protein (HBx is known to play a key role in the development of hepatocellular carcinoma (HCC. Several cellular proteins have been reported to be over-expressed in HBV-associated HCC tissues, but their role in the HBV-mediated oncogenesis remains largely unknown. Here, we explored the effect of the over-expressed cellular protein, a ribosomal protein S3a (RPS3a, on the HBx-induced NF-κB signaling as a critical step for HCC development. The enhancement of HBx-induced NF-κB signaling by RPS3a was investigated by its ability to translocate NF-κB (p65 into the nucleus and the knock-down analysis of RPS3a. Notably, further study revealed that the enhancement of NF-κB by RPS3a is mediated by its novel chaperoning activity toward physiological HBx. The over-expression of RPS3a significantly increased the solubility of highly aggregation-prone HBx. This chaperoning function of RPS3a for HBx is closely correlated with the enhanced NF-κB activity by RPS3a. In addition, the mutational study of RPS3a showed that its N-terminal domain (1-50 amino acids is important for the chaperoning function and interaction with HBx. The results suggest that RPS3a, via extra-ribosomal chaperoning function for HBx, contributes to virally induced oncogenesis by enhancing HBx-induced NF-κB signaling pathway.

  2. Expression of the promoter of HyPRP, an embryo-specific gene from Zea mays in maize and tobacco transgenic plants.

    Science.gov (United States)

    José-Estanyol, Matilde; Pérez, Pascual; Puigdomènech, Pere

    2005-08-15

    zmHyPRP is a gene specifically expressed in maize immature embryos where its transcripts are mainly observed in the scutellum. It has been shown that zmHyPRP expression in the embryo is arrested when ABA levels increase at the beginning of the maturation stage. Here we report the ability of 2 Kb zmHyPRP promoter to reproduce the zmHyPRP gene specific expression pattern in the maize embryo and its repression by ABA at the end of the morphogenetic process. Three different approaches have been used, transient particle bombardment of maize immature excised embryos and stable transformation of maize and tobacco plants with a construct containing 2 Kb of zmHyPRP promoter fused to the GUS gene. This construct has shown to confer specific expression to maize and tobacco embryos but in tobacco expression in the embryo was very low. The same construct was also negatively regulated by ABA in embryos of both species. This suggests that 2 Kb of the zmHyPRP promoter contain all regulatory elements sufficient to confer the developmental expression patterns of the gene characterized to date.

  3. Effect of Platelet-Rich Plasma (PRP versus Autologous Whole Blood on Pain and Function Improvement in Tennis Elbow: A Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Seyed Ahmad Raeissadat

    2014-01-01

    Full Text Available Background. Autologous whole blood and platelet-rich plasma (PRP have been both suggested to treat chronic tennis elbow. The aim of the present study was to compare the effects of PRP versus autologous whole blood local injection in chronic tennis elbow. Methods. Forty patients with tennis elbow were randomly divided into 2 groups. Group 1 was treated with a single injection of 2 mL of autologous PRP and group 2 with 2 mL of autologous blood. Tennis elbow strap, stretching, and strengthening exercises were administered for both groups during a 2-month followup. Pain and functional improvements were assessed using visual analog scale (VAS, modified Mayo Clinic performance index for the elbow, and pressure pain threshold (PPT at 0, 4, and 8 weeks. Results. All pain and functional variables including VAS, PPT, and Mayo scores improved significantly in both groups 4 weeks after injection. No statistically significant difference was noted between groups regarding pain scores in 4-week follow-up examination (P>0.05. At 8-week reevaluations, VAS and Mayo scores improved only in PRP group (P<0.05. Conclusion. PRP and autologous whole blood injections are both effective to treat chronic lateral epicondylitis. PRP might be slightly superior in 8-week followup. However, further studies are suggested to get definite conclusion.

  4. Effect of Platelet-Rich Plasma (PRP) versus Autologous Whole Blood on Pain and Function Improvement in Tennis Elbow: A Randomized Clinical Trial.

    Science.gov (United States)

    Raeissadat, Seyed Ahmad; Sedighipour, Leyla; Rayegani, Seyed Mansoor; Bahrami, Mohammad Hasan; Bayat, Masume; Rahimi, Rosa

    2014-01-01

    Background. Autologous whole blood and platelet-rich plasma (PRP) have been both suggested to treat chronic tennis elbow. The aim of the present study was to compare the effects of PRP versus autologous whole blood local injection in chronic tennis elbow. Methods. Forty patients with tennis elbow were randomly divided into 2 groups. Group 1 was treated with a single injection of 2 mL of autologous PRP and group 2 with 2 mL of autologous blood. Tennis elbow strap, stretching, and strengthening exercises were administered for both groups during a 2-month followup. Pain and functional improvements were assessed using visual analog scale (VAS), modified Mayo Clinic performance index for the elbow, and pressure pain threshold (PPT) at 0, 4, and 8 weeks. Results. All pain and functional variables including VAS, PPT, and Mayo scores improved significantly in both groups 4 weeks after injection. No statistically significant difference was noted between groups regarding pain scores in 4-week follow-up examination (P > 0.05). At 8-week reevaluations, VAS and Mayo scores improved only in PRP group (P PRP and autologous whole blood injections are both effective to treat chronic lateral epicondylitis. PRP might be slightly superior in 8-week followup. However, further studies are suggested to get definite conclusion.

  5. Diabetic Peripheral Neuropathy: Should a Chaperone Accompany Our Therapeutic Approach?

    Science.gov (United States)

    Farmer, Kevin L.; Li, Chengyuan

    2012-01-01

    Diabetic peripheral neuropathy (DPN) is a common complication of diabetes that is associated with axonal atrophy, demyelination, blunted regenerative potential, and loss of peripheral nerve fibers. The development and progression of DPN is due in large part to hyperglycemia but is also affected by insulin deficiency and dyslipidemia. Although numerous biochemical mechanisms contribute to DPN, increased oxidative/nitrosative stress and mitochondrial dysfunction seem intimately associated with nerve dysfunction and diminished regenerative capacity. Despite advances in understanding the etiology of DPN, few approved therapies exist for the pharmacological management of painful or insensate DPN. Therefore, identifying novel therapeutic strategies remains paramount. Because DPN does not develop with either temporal or biochemical uniformity, its therapeutic management may benefit from a multifaceted approach that inhibits pathogenic mechanisms, manages inflammation, and increases cytoprotective responses. Finally, exercise has long been recognized as a part of the therapeutic management of diabetes, and exercise can delay and/or prevent the development of painful DPN. This review presents an overview of existing therapies that target both causal and symptomatic features of DPN and discusses the role of up-regulating cytoprotective pathways via modulating molecular chaperones. Overall, it may be unrealistic to expect that a single pharmacologic entity will suffice to ameliorate the multiple symptoms of human DPN. Thus, combinatorial therapies that target causal mechanisms and enhance endogenous reparative capacity may enhance nerve function and improve regeneration in DPN if they converge to decrease oxidative stress, improve mitochondrial bioenergetics, and increase response to trophic factors. PMID:22885705

  6. Regulation of GPCR Anterograde Trafficking by Molecular Chaperones and Motifs.

    Science.gov (United States)

    Young, Brent; Wertman, Jaime; Dupré, Denis J

    2015-01-01

    G protein-coupled receptors (GPCRs) make up a superfamily of integral membrane proteins that respond to a wide variety of extracellular stimuli, giving them an important role in cell function and survival. They have also proven to be valuable targets in the fight against various diseases. As such, GPCR signal regulation has received considerable attention over the last few decades. With the amplitude of signaling being determined in large part by receptor density at the plasma membrane, several endogenous mechanisms for modulating GPCR expression at the cell surface have come to light. It has been shown that cell surface expression is determined by both exocytic and endocytic processes. However, the body of knowledge surrounding GPCR trafficking from the endoplasmic reticulum to the plasma membrane, commonly known as anterograde trafficking, has considerable room for growth. We focus here on the current paradigms of anterograde GPCR trafficking. We will discuss the regulatory role of both the general and "nonclassical private" chaperone systems in GPCR trafficking as well as conserved motifs that serve as modulators of GPCR export from the endoplasmic reticulum and Golgi apparatus. Together, these topics summarize some of the known mechanisms by which the cell regulates anterograde GPCR trafficking. © 2015 Elsevier Inc. All rights reserved.

  7. Sigma-1 receptor chaperone at the ER-mitochondrion interface mediates the mitochondrion-ER-nucleus signaling for cellular survival.

    Science.gov (United States)

    Mori, Tomohisa; Hayashi, Teruo; Hayashi, Eri; Su, Tsung-Ping

    2013-01-01

    The membrane of the endoplasmic reticulum (ER) of a cell forms contacts directly with mitochondria whereby the contact is referred to as the mitochondrion-associated ER membrane or the MAM. Here we found that the MAM regulates cellular survival via an MAM-residing ER chaperone the sigma-1 receptor (Sig-1R) in that the Sig-1R chaperones the ER stress sensor IRE1 to facilitate inter-organelle signaling for survival. IRE1 is found in this study to be enriched at the MAM in CHO cells. We found that IRE1 is stabilized at the MAM by Sig-1Rs when cells are under ER stress. Sig-1Rs stabilize IRE1 and thus allow for conformationally correct IRE1 to dimerize into the long-lasting, activated endonuclease. The IRE1 at the MAM also responds to reactive oxygen species derived from mitochondria. Therefore, the ER-mitochondrion interface serves as an important subcellular entity in the regulation of cellular survival by enhancing the stress-responding signaling between mitochondria, ER, and nucleus.

  8. Structure of trigger factor binding domain in biologically homologous complex with eubacterial ribosome reveals its chaperone action

    Energy Technology Data Exchange (ETDEWEB)

    Baram, David; Pyetan, Erez; Sittner, Assa; Auerbach-Nevo, Tamar; Bashan, Anat; Yonath, Ada (WIS-I)

    2010-07-13

    Trigger factor (TF), the first chaperone in eubacteria to encounter the emerging nascent chain, binds to the large ribosomal subunit in the vicinity of the protein exit tunnel opening and forms a sheltered folding space. Here, we present the 3.5-{angstrom} crystal structure of the physiological complex of the large ribosomal subunit from the eubacterium Deinococcus radiodurans with the N-terminal domain of TF (TFa) from the same organism. For anchoring, TFa exploits a small ribosomal surface area in the vicinity of proteins L23 and L29, by using its 'signature motif' as well as additional structural elements. The molecular details of TFa interactions reveal that L23 is essential for the association of TF with the ribosome and may serve as a channel of communication with the nascent chain progressing in the tunnel. L29 appears to induce a conformational change in TFa, which results in the exposure of TFa hydrophobic patches to the opening of the ribosomal exit tunnel, thus increasing its affinity for hydrophobic segments of the emerging nascent polypeptide. This observation implies that, in addition to creating a protected folding space for the emerging nascent chain, TF association with the ribosome prevents aggregation by providing a competing hydrophobic environment and may be critical for attaining the functional conformation necessary for chaperone activity.

  9. Immunogenicity and safety of a fully liquid aluminum phosphate adjuvanted Haemophilus influenzae type b PRP-CRM197-conjugate vaccine in healthy Japanese children: A phase III, randomized, observer-blind, multicenter, parallel-group study.

    Science.gov (United States)

    Togashi, Takehiro; Mitsuya, Nodoka; Kogawara, Osamu; Sumino, Shuji; Takanami, Yohei; Sugizaki, Kayoko

    2016-08-31

    Broad use of monovalent Haemophilus influenzae type b (Hib) conjugate vaccines based on the capsular polysaccharide polyribosyl-ribitol phosphate (PRP), has significantly reduced invasive Hib disease burden in children worldwide, particularly in children aged vaccine has been widely used since the initiation of public funding programs followed by a routine vaccination designation in 2013. We compared the immunogenicity and safety of PRP conjugated to a non-toxic diphtheria toxin mutant (PRP-CRM197) vaccine with the PRP-T vaccine when administered subcutaneously to healthy Japanese children in a phase III study. Additionally, we evaluated the immunogenicity and safety profiles of a diphtheria-tetanus acellular pertussis (DTaP) combination vaccine when concomitantly administered with either PRP-CRM197 or PRP-T vaccines. The primary endpoint was the "long-term seroprotection rate", defined as the group proportion with anti-PRP antibody titers ⩾1.0μg/mL, after the primary series. Long-term seroprotection rates were 99.3% in the PRP-CRM197 group and 95.6% in the PRP-T group. The intergroup difference (PRP-CRM197 group - PRP-T group) was 3.7% (95% confidence interval: 0.099-7.336), demonstrating that PRP-CRM197 vaccine was non-inferior to PRP-T vaccine (pvaccination was higher in the PRP-CRM197 group than in PRP-T. Concomitant administration of PRP-CRM197 vaccine with DTaP vaccine showed no differences in terms of immunogenicity compared with concomitant vaccination with PRP-T vaccine and DTaP vaccine. Although CRM197 vaccine had higher local reactogenicity, overall, both Hib vaccines had acceptable safety and tolerability profiles. The immunogenicity of PRP-CRM197 vaccine administered subcutaneously as a three-dose primary series in children followed by a booster vaccination 1year after the primary series induced protective levels of Hib antibodies with no safety or tolerability concerns. Registered on ClinicalTrials.gov: NCT01379846. Copyright © 2016 The Authors

  10. Structure and functions of the chaperone-like p97/CDC48 in plants.

    Science.gov (United States)

    Bègue, Hervé; Jeandroz, Sylvain; Blanchard, Cécile; Wendehenne, David; Rosnoblet, Claire

    2017-01-01

    The chaperone-like p97 is a member of the AAA+ ATPase enzyme family that contributes to numerous cellular activities. P97 has been broadly studied in mammals (VCP/p97) and yeasts (CDC48: Cell Division Cycle 48/p97) and numerous investigations highlighted that this protein is post-translationally regulated, is structured in homohexamer and interacts with partners and cofactors that direct it to distinct cellular signalization pathway including protein quality control and degradation, cell cycle regulation, genome stability, vesicular trafficking, autophagy and immunity. p97 is also conserved in plants (CDC48) but its functions are less understood. In the present review we intended to present the state of the art of the structure, regulation and functions of CDC48 in plants. Evidence accumulated underline that CDC48 plays a crucial role in development, cell cycle regulation and protein turnover in plants. Furthermore, its involvement in plant immunity has recently emerged and first interacting partners have been identified, shedding light on its putative cellular activities. Identification of emerging functions of CDC48 in plants opens new roads of research in immunity and provides new insights into the mechanisms of protein quality control. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Adipocyte lipid chaperone AP2 is a secreted adipokine regulating hepatic glucose production.

    Science.gov (United States)

    Cao, Haiming; Sekiya, Motohiro; Ertunc, Meric Erikci; Burak, M Furkan; Mayers, Jared R; White, Ariel; Inouye, Karen; Rickey, Lisa M; Ercal, Baris C; Furuhashi, Masato; Tuncman, Gürol; Hotamisligil, Gökhan S

    2013-05-07

    Proper control of hepatic glucose production is central to whole-body glucose homeostasis, and its disruption plays a major role in diabetes. Here, we demonstrate that although established as an intracellular lipid chaperone, aP2 is in fact actively secreted from adipocytes to control liver glucose metabolism. Secretion of aP2 from adipocytes is regulated by fasting- and lipolysis-related signals, and circulating aP2 levels are markedly elevated in mouse and human obesity. Recombinant aP2 stimulates glucose production and gluconeogenic activity in primary hepatocytes in vitro and in lean mice in vivo. In contrast, neutralization of secreted aP2 reduces glucose production and corrects the diabetic phenotype of obese mice. Hyperinsulinemic-euglycemic and pancreatic clamp studies upon aP2 administration or neutralization demonstrated actions of aP2 in liver. We conclude that aP2 is an adipokine linking adipocytes to hepatic glucose production and that neutralizing secreted aP2 may represent an effective therapeutic strategy against diabetes. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Transgenic Rabbits Expressing Ovine PrP Are Susceptible to Scrapie

    Science.gov (United States)

    Sarradin, Pierre; Viglietta, Céline; Limouzin, Claude; Andréoletti, Olivier; Daniel-Carlier, Nathalie; Barc, Céline; Leroux-Coyau, Mathieu; Berthon, Patricia; Chapuis, Jérôme; Rossignol, Christelle; Gatti, Jean-Luc; Belghazi, Maya; Labas, Valérie; Vilotte, Jean-Luc; Béringue, Vincent; Lantier, Frédéric; Laude, Hubert; Houdebine, Louis-Marie

    2015-01-01

    Transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative diseases affecting a wide range of mammalian species. They are caused by prions, a proteinaceous pathogen essentially composed of PrPSc, an abnormal isoform of the host encoded cellular prion protein PrPC. Constrained steric interactions between PrPSc and PrPC are thought to provide prions with species specificity, and to control cross-species transmission into other host populations, including humans. Transgenetic expression of foreign PrP genes has been successfully and widely used to overcome the recognized resistance of mouse to foreign TSE sources. Rabbit is one of the species that exhibit a pronounced resistance to TSEs. Most attempts to infect experimentally rabbit have failed, except after inoculation with cell-free generated rabbit prions. To gain insights on the molecular determinants of the relative resistance of rabbits to prions, we generated transgenic rabbits expressing the susceptible V136R154Q171 allele of the ovine PRNP gene on a rabbit wild type PRNP New Zealand background and assessed their experimental susceptibility to scrapie prions. All transgenic animals developed a typical TSE 6–8 months after intracerebral inoculation, whereas wild type rabbits remained healthy more than 700 days after inoculation. Despite the endogenous presence of rabbit PrPC, only ovine PrPSc was detectable in the brains of diseased animals. Collectively these data indicate that the low susceptibility of rabbits to prion infection is not enciphered within their non-PrP genetic background. PMID:26248157

  13. Chemical chaperones reduce ionizing radiation-induced endoplasmic reticulum stress and cell death in IEC-6 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sang; Lee, Hae-June; Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Jeong, Jae-Hoon [Division of Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Kang, Seongman [Division of Life Sciences, Korea University, Seoul 136-701 (Korea, Republic of); Lim, Young-Bin, E-mail: yblim@kirams.re.kr [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of)

    2014-07-25

    Highlights: • UPR activation precedes caspase activation in irradiated IEC-6 cells. • Chemical ER stress inducers radiosensitize IEC-6 cells. • siRNAs that targeted ER stress responses ameliorate IR-induced cell death. • Chemical chaperons prevent cell death in irradiated IEC-6 cells. - Abstract: Radiotherapy, which is one of the most effective approaches to the treatment of various cancers, plays an important role in malignant cell eradication in the pelvic area and abdomen. However, it also generates some degree of intestinal injury. Apoptosis in the intestinal epithelium is the primary pathological factor that initiates radiation-induced intestinal injury, but the mechanism by which ionizing radiation (IR) induces apoptosis in the intestinal epithelium is not clearly understood. Recently, IR has been shown to induce endoplasmic reticulum (ER) stress, thereby activating the unfolded protein response (UPR) signaling pathway in intestinal epithelial cells. However, the consequences of the IR-induced activation of the UPR signaling pathway on radiosensitivity in intestinal epithelial cells remain to be determined. In this study, we investigated the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhanced IR-induced caspase 3 activation and DNA fragmentation in intestinal epithelial cells. Knockdown of Xbp1 or Atf6 with small interfering RNA inhibited IR-induced caspase 3 activation. Treatment with chemical chaperones prevented ER stress and subsequent apoptosis in IR-exposed intestinal epithelial cells. Our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Furthermore, inhibiting ER stress may be an effective strategy to prevent IR-induced intestinal injury.

  14. Characterization and Structure of a Zn[superscript 2+] and [2Fe-2S]-containing Copper Chaperone from Archaeoglobus fulgidus

    Energy Technology Data Exchange (ETDEWEB)

    Sazinsky, Matthew H.; LeMoine, Benjamin; Orofino, Maria; Davydov, Roman; Bencze, Krisztina Z.; Stemmler, Timothy L.; Hoffman, Brian M.; Arguello, Jose M.; Rosenzweig, Amy C. (Worcester); (WSU-MED); (NWU)

    2010-03-08

    Bacterial CopZ proteins deliver copper to P{sub 1B}-type Cu{sup +}-ATPases that are homologous to the human Wilson and Menkes disease proteins. The genome of the hyperthermophile Archaeoglobus fulgidus encodes a putative CopZ copper chaperone that contains an unusual cysteine-rich N-terminal domain of 130 amino acids in addition to a C-terminal copper binding domain with a conserved CXXC motif. The N-terminal domain (CopZ-NT) is homologous to proteins found only in extremophiles and is the only such protein that is fused to a copper chaperone. Surprisingly, optical, electron paramagnetic resonance, and x-ray absorption spectroscopic data indicate the presence of a [2Fe-2S] cluster in CopZ-NT. The intact CopZ protein binds two copper ions, one in each domain. The 1.8 {angstrom} resolution crystal structure of CopZ-NT reveals that the [2Fe-2S] cluster is housed within a novel fold and that the protein also binds a zinc ion at a four-cysteine site. CopZ can deliver Cu{sup +} to the A. fulgidus CopA N-terminal metal binding domain and is capable of reducing Cu{sup 2+} to Cu{sup +}. This unique fusion of a redox-active domain with a CXXC-containing copper chaperone domain is relevant to the evolution of copper homeostatic mechanisms and suggests new models for copper trafficking.

  15. The DnaK Chaperone Uses Different Mechanisms To Promote and Inhibit Replication of Vibrio cholerae Chromosome 2

    Energy Technology Data Exchange (ETDEWEB)

    Jha, Jyoti K.; Li, Mi; Ghirlando, Rodolfo; Miller Jenkins, Lisa M.; Wlodawer, Alexander; Chattoraj, Dhruba; Dunny, Gary M.

    2017-04-18

    promotes initiation by reducing the initiator’s propensity to dimerize. Dimerization of the initiator of the putative plasmid progenitor of Chr2 is also reduced by DnaK, which promotes initiation. Paradoxically, the DnaK binding also promotes replication inhibition by reducing an autoinhibitory activity of RctB. In the plasmid-to-chromosome transition, it appears that the initiator has acquired an autoinhibitory activity and along with it a new chaperone activity that apparently helps to control replication inhibition independently of replication promotion.

  16. Transcription recovery after DNA damage requires chromatin priming by the H3.3 histone chaperone HIRA.

    Science.gov (United States)

    Adam, Salomé; Polo, Sophie E; Almouzni, Geneviève

    2013-09-26

    Understanding how to recover fully functional and transcriptionally active chromatin when its integrity has been challenged by genotoxic stress is a critical issue. Here, by investigating how chromatin dynamics regulate transcriptional activity in response to DNA damage in human cells, we identify a pathway involving the histone chaperone histone regulator A (HIRA) to promote transcription restart after UVC damage. Our mechanistic studies reveal that HIRA accumulates at sites of UVC irradiation upon detection of DNA damage prior to repair and deposits newly synthesized H3.3 histones. This local action of HIRA depends on ubiquitylation events associated with damage recognition. Furthermore, we demonstrate that the early and transient function of HIRA in response to DNA damage primes chromatin for later reactivation of transcription. We propose that HIRA-dependent histone deposition serves as a chromatin bookmarking system to facilitate transcription recovery after genotoxic stress. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Structure and Histone Binding Properties of the Vps75-Rtt109 Chaperone-Lysine Acetyltransferase Complex

    Energy Technology Data Exchange (ETDEWEB)

    Su, Dan; Hu, Qi; Zhou, Hui; Thompson, James R.; Xu, Rui-Ming; Zhang, Zhiguo; Mer, Georges (Mayo); (Chinese Aca. Sci.)

    2011-11-02

    The histone chaperone Vps75 presents the remarkable property of stimulating the Rtt109-dependent acetylation of several histone H3 lysine residues within (H3-H4){sub 2} tetramers. To investigate this activation mechanism, we determined x-ray structures of full-length Vps75 in complex with full-length Rtt109 in two crystal forms. Both structures show similar asymmetric assemblies of a Vps75 dimer bound to an Rtt109 monomer. In the Vps75-Rtt109 complexes, the catalytic site of Rtt109 is confined to an enclosed space that can accommodate the N-terminal tail of histone H3 in (H3-H4){sub 2}. Investigation of Vps75-Rtt109-(H3-H4)2 and Vps75-(H3-H4)2 complexes by NMR spectroscopy-probed hydrogen/deuterium exchange suggests that Vps75 guides histone H3 in the catalytic enclosure. These findings clarify the basis for the enhanced acetylation of histone H3 tail residues by Vps75-Rtt109.

  18. Interaction specificity between the chaperone and proteolytic components of the cyanobacterial Clp protease.

    Science.gov (United States)

    Tryggvesson, Anders; Ståhlberg, Frida M; Mogk, Axel; Zeth, Kornelius; Clarke, Adrian K

    2012-09-01

    The Clp protease is conserved among eubacteria and most eukaryotes, and uses ATP to drive protein substrate unfolding and translocation into a chamber of sequestered proteolytic active sites. In plant chloroplasts and cyanobacteria, the essential constitutive Clp protease consists of the Hsp100/ClpC chaperone partnering a proteolytic core of catalytic ClpP and noncatalytic ClpR subunits. In the present study, we have examined putative determinants conferring the highly specific association between ClpC and the ClpP3/R core from the model cyanobacterium Synechococcus elongatus. Two conserved sequences in the N-terminus of ClpR (tyrosine and proline motifs) and one in the N-terminus of ClpP3 (MPIG motif) were identified as being crucial for the ClpC-ClpP3/R association. These N-terminal domains also influence the stability of the ClpP3/R core complex itself. A unique C-terminal sequence was also found in plant and cyanobacterial ClpC orthologues just downstream of the P-loop region previously shown in Escherichia coli to be important for Hsp100 association to ClpP. This R motif in Synechococcus ClpC confers specificity for the ClpP3/R core and prevents association with E. coli ClpP; its removal from ClpC reverses this core specificity.

  19. Histone chaperone HIRA regulates neural progenitor cell proliferation and neurogenesis via β-catenin.

    Science.gov (United States)

    Li, Yanxin; Jiao, Jianwei

    2017-07-03

    Histone cell cycle regulator (HIRA) is a histone chaperone and has been identified as an epigenetic regulator. Subsequent studies have provided evidence that HIRA plays key roles in embryonic development, but its function during early neurogenesis remains unknown. Here, we demonstrate that HIRA is enriched in neural progenitor cells, and HIRA knockdown reduces neural progenitor cell proliferation, increases terminal mitosis and cell cycle exit, and ultimately results in premature neuronal differentiation. Additionally, we demonstrate that HIRA enhances β-catenin expression by recruiting H3K4 trimethyltransferase Setd1A, which increases H3K4me3 levels and heightens the promoter activity of β-catenin. Significantly, overexpression of HIRA, HIRA N-terminal domain, or β-catenin can override neurogenesis abnormities caused by HIRA defects. Collectively, these data implicate that HIRA, cooperating with Setd1A, modulates β-catenin expression and then regulates neurogenesis. This finding represents a novel epigenetic mechanism underlying the histone code and has profound and lasting implications for diseases and neurobiology. © 2017 Li and Jiao.

  20. Corticosteroid Receptors, Their Chaperones and Cochaperones: How Do They Modulate Adipogenesis?

    Directory of Open Access Journals (Sweden)

    Judith Toneatto

    2014-11-01

    Full Text Available It is well known that glucocorticoids and mineralocorticoids are part of the list of hormones that control adipogenesis as well as different aspects of the physiology of the adipose tissue. Their actions are mediated through their binding to the glucocorticoid and the mineralocorticoid receptors (GR and MR, respectively, in complex with heat shock proteins (Hsps and high molecular weight immunophilins (IMMs. Albeit many aspects of the molecular mechanism of the corticosteroid receptors are not fully elucidated yet, it was not until recently that the first evidences of the functional importance of Hsps and IMMs in the process of adipocyte differentiation have been described. Hsp90 and the high molecular weight IMM FKBP51 modulate GR and MR activity at multiple levels, that is, hormone binding affinity, their subcellular distribution, and the transcriptional status, among other aspects of the NR function. Interestingly, it has recently been described that Hsp90 and FKBP51 also participate in the control of PPARγ, a key transcription factor in the control of adipogenesis and the maintenance of the adipocyte phenotype. In addition, novel roles have been uncovered for FKBP51 in the organization of the nuclear architecture through its participation in the reorganization of the nuclear lamina and the control of the subnuclear distribution of GR. Thus, the aim of this review is to integrate and discuss the actual understanding of the role of corticosteroid receptors, their chaperones and cochaperones, in the process of adipocyte differentiation.

  1. Autologous platelet-rich plasma (PRP) in chronic penile lichen sclerosus: the impact on tissue repair and patient quality of life.

    Science.gov (United States)

    Casabona, Francesco; Gambelli, Ilaria; Casabona, Federica; Santi, Pierluigi; Santori, Gregorio; Baldelli, Ilaria

    2017-04-01

    Lichen sclerosus (LS) is a chronic inflammatory skin condition that frequently involves the anogenital region. Ongoing research is focused on finding more effective treatments for tissue repair and reducing symptoms. The aim of this study is to evaluate the effectiveness of platelet-rich plasma (PRP) local injections in penile LS. Forty-five male patients affected by penile LS underwent injections of autologous PRP in the affected skin areas. Age at diagnosis and at first treatment, number of treatments, clinical conditions (phimosis, splitting, inflammation, synechiae, meatus stenosis), symptoms (pain, burning, itching), and functional impairment were considered. Treatment efficacy was also evaluated through the Investigator's Global Assessment (IGA) on a six-point Likert scale and the Dermatology Life Quality Index (DLQI). The patient age at LS diagnosis was 36.20 ± 9.19 years, while the mean age at the first PRP treatment was 42.96 ± 11.32 years (p < 0.001). The number of treatments/patient ranged from 2 to 10. The follow-up was 17.60 ± 5.63 months. After PRP injections, it was observed in all patients a significant improvement in clinical conditions, with reduction/disappearance of symptoms. Topical steroid therapy, interrupted before PRP treatment, was not restarted by any patient. Only one patient underwent a later circumcision procedure. Both IGA scale and DLQI score showed a significant difference (p < 0.001) before and after PRP treatment. PRP treatment in penile LS seems to be helpful to regenerate scarring, reduce symptoms, and improve patient quality of life. Further studies are necessary to evaluate long-term results.

  2. Exploring the mechanisms used by promiscuous chaperones to assist protein folding in the cell

    Science.gov (United States)

    Jewett, Andrew I.

    There are two popular theories to explain how molecular chaperones boost the yield of folded protein in the cell: According to the Anfinsen cage model, (ACM) chaperonins protect denatured proteins from aggregation. A competing theory, the iterative annealing model (IAM) claims that ATP regulated chaperone binding and release accelerates folding by freeing proteins from long-lived kinetic traps. We present experimental and kinetic evidence to argue that the IAM is not a complete picture of how the GroEL/ES chaperonin works. Surprisingly some substrate proteins experience folding rate enhancements without undergoing multiple rounds of ATP-induced binding and release from the chaperonin. An explanation of this data requires going beyond the ACM and IAM models. Our work uses molecular dynamics simulations to investigate the folding of a highly frustrated protein within a chaperonin cavity. The chaperonin interior is modeled by a sphere with variable degree of attraction to the protein inside. We demonstrate that this cavity, similar to the weakly hydrophobic interior of the GroEL cavity upon complexion with ATP and GroES, is sufficient to accelerate the folding of a frustrated protein by more than an order of magnitude. Our simulations uncover a novel form of the IAM in which the substrate exhibits spontaneous binding and release from the wall of the chaperonin cage. This mimics the behavior observed in the standard IAM, with the difference that thermal fluctuations, rather than ATP, allow the substrate to unbind from the chaperone. An growing number of smaller cageless chaperones have been discovered that can assist protein folding without the consumption of ATP, including artificial "minichaperones" (fragments of larger chaperones). It is tempting to speculate that the same thermally-driven IAM mechanism could play a role with these chaperones as well. We performed additional simulations of protein folding outside the sphere. We find that in order to accelerate

  3. Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Andia, Isabel; Zumstein, Matthias A; Zhang, Chang-Qing; Pinto, Nelson R; Bielecki, Tomasz

    2014-01-01

    Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) - are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics.

  4. Molecular Chaperones of Leishmania: Central Players in Many Stress-Related and -Unrelated Physiological Processes

    Science.gov (United States)

    Requena, Jose M.; Montalvo, Ana M.; Fraga, Jorge

    2015-01-01

    Molecular chaperones are key components in the maintenance of cellular homeostasis and survival, not only during stress but also under optimal growth conditions. Folding of nascent polypeptides is supported by molecular chaperones, which avoid the formation of aggregates by preventing nonspecific interactions and aid, when necessary, the translocation of proteins to their correct intracellular localization. Furthermore, when proteins are damaged, molecular chaperones may also facilitate their refolding or, in the case of irreparable proteins, their removal by the protein degradation machinery of the cell. During their digenetic lifestyle, Leishmania parasites encounter and adapt to harsh environmental conditions, such as nutrient deficiency, hypoxia, oxidative stress, changing pH, and shifts in temperature; all these factors are potential triggers of cellular stress. We summarize here our current knowledge on the main types of molecular chaperones in Leishmania and their functions. Among them, heat shock proteins play important roles in adaptation and survival of this parasite against temperature changes associated with its passage from the poikilothermic insect vector to the warm-blooded vertebrate host. The study of structural features and the function of chaperones in Leishmania biology is providing opportunities (and challenges) for drug discovery and improving of current treatments against leishmaniasis. PMID:26167482

  5. Molecular Chaperones of Leishmania: Central Players in Many Stress-Related and -Unrelated Physiological Processes

    Directory of Open Access Journals (Sweden)

    Jose M. Requena

    2015-01-01

    Full Text Available Molecular chaperones are key components in the maintenance of cellular homeostasis and survival, not only during stress but also under optimal growth conditions. Folding of nascent polypeptides is supported by molecular chaperones, which avoid the formation of aggregates by preventing nonspecific interactions and aid, when necessary, the translocation of proteins to their correct intracellular localization. Furthermore, when proteins are damaged, molecular chaperones may also facilitate their refolding or, in the case of irreparable proteins, their removal by the protein degradation machinery of the cell. During their digenetic lifestyle, Leishmania parasites encounter and adapt to harsh environmental conditions, such as nutrient deficiency, hypoxia, oxidative stress, changing pH, and shifts in temperature; all these factors are potential triggers of cellular stress. We summarize here our current knowledge on the main types of molecular chaperones in Leishmania and their functions. Among them, heat shock proteins play important roles in adaptation and survival of this parasite against temperature changes associated with its passage from the poikilothermic insect vector to the warm-blooded vertebrate host. The study of structural features and the function of chaperones in Leishmania biology is providing opportunities (and challenges for drug discovery and improving of current treatments against leishmaniasis.

  6. A Structural and Functional Comparison Between Infectious and Non-Infectious Autocatalytic Recombinant PrP Conformers.

    Directory of Open Access Journals (Sweden)

    Geoffrey P Noble

    2015-06-01

    Full Text Available Infectious prions contain a self-propagating, misfolded conformer of the prion protein termed PrPSc. A critical prediction of the protein-only hypothesis is that autocatalytic PrPSc molecules should be infectious. However, some autocatalytic recombinant PrPSc molecules have low or undetectable levels of specific infectivity in bioassays, and the essential determinants of recombinant prion infectivity remain obscure. To identify structural and functional features specifically associated with infectivity, we compared the properties of two autocatalytic recombinant PrP conformers derived from the same original template, which differ by >105-fold in specific infectivity for wild-type mice. Structurally, hydrogen/deuterium exchange mass spectrometry (DXMS studies revealed that solvent accessibility profiles of infectious and non-infectious autocatalytic recombinant PrP conformers are remarkably similar throughout their protease-resistant cores, except for two domains encompassing residues 91-115 and 144-163. Raman spectroscopy and immunoprecipitation studies confirm that these domains adopt distinct conformations within infectious versus non-infectious autocatalytic recombinant PrP conformers. Functionally, in vitro prion propagation experiments show that the non-infectious conformer is unable to seed mouse PrPC substrates containing a glycosylphosphatidylinositol (GPI anchor, including native PrPC. Taken together, these results indicate that having a conformation that can be specifically adopted by post-translationally modified PrPC molecules is an essential determinant of biological infectivity for recombinant prions, and suggest that this ability is associated with discrete features of PrPSc structure.

  7. A Structural and Functional Comparison Between Infectious and Non-Infectious Autocatalytic Recombinant PrP Conformers

    Science.gov (United States)

    Noble, Geoffrey P.; Wang, Daphne W.; Walsh, Daniel J.; Barone, Justin R.; Miller, Michael B.; Nishina, Koren A.; Li, Sheng; Supattapone, Surachai

    2015-01-01

    Infectious prions contain a self-propagating, misfolded conformer of the prion protein termed PrPSc. A critical prediction of the protein-only hypothesis is that autocatalytic PrPSc molecules should be infectious. However, some autocatalytic recombinant PrPSc molecules have low or undetectable levels of specific infectivity in bioassays, and the essential determinants of recombinant prion infectivity remain obscure. To identify structural and functional features specifically associated with infectivity, we compared the properties of two autocatalytic recombinant PrP conformers derived from the same original template, which differ by >105-fold in specific infectivity for wild-type mice. Structurally, hydrogen/deuterium exchange mass spectrometry (DXMS) studies revealed that solvent accessibility profiles of infectious and non-infectious autocatalytic recombinant PrP conformers are remarkably similar throughout their protease-resistant cores, except for two domains encompassing residues 91-115 and 144-163. Raman spectroscopy and immunoprecipitation studies confirm that these domains adopt distinct conformations within infectious versus non-infectious autocatalytic recombinant PrP conformers. Functionally, in vitro prion propagation experiments show that the non-infectious conformer is unable to seed mouse PrPC substrates containing a glycosylphosphatidylinositol (GPI) anchor, including native PrPC. Taken together, these results indicate that having a conformation that can be specifically adopted by post-translationally modified PrPC molecules is an essential determinant of biological infectivity for recombinant prions, and suggest that this ability is associated with discrete features of PrPSc structure. PMID:26125623

  8. A novel expression system for production of soluble prion proteins in E. coli

    Directory of Open Access Journals (Sweden)

    Abskharon Romany NN

    2012-01-01

    Full Text Available Abstract Expression of eukaryotic proteins in Escherichia coli is challenging, especially when they contain disulfide bonds. Since the discovery of the prion protein (PrP and its role in transmissible spongiform encephalopathies, the need to obtain large quantities of the recombinant protein for research purposes has been essential. Currently, production of recombinant PrP is achieved by refolding protocols. Here, we show that the co-expression of two different PrP with the human Quiescin Sulfhydryl OXidase (QSOX, a human chaperone with thiol/disulfide oxidase activity, in the cytoplasm of E. coli produces soluble recombinant PrP. The structural integrity of the soluble PrP has been confirmed by nuclear magnetic resonance spectroscopy, demonstrating that properly folded PrP can be easily expressed in bacteria. Furthermore, the soluble recombinant PrP produced with this method can be used for functional and structural studies.

  9. Production of 10S-hydroxy-8(E)-octadecenoic acid from oleic acid by whole recombinant Escherichia coli cells expressing 10S-dioxygenase from Nostoc punctiforme PCC 73102 with the aid of a chaperone.

    Science.gov (United States)

    Kim, Min-Ji; Seo, Min-Ju; Shin, Kyung-Chul; Oh, Deok-Kun

    2017-01-01

    To increase the production of 10S-hydroxy-8(E)-octadecenoic acid from oleic acid by whole recombinant Escherichia coli cells expressing Nostoc punctiforme 10S-dioxygenase with the aid of a chaperone. The optimal conditions for 10S-hydroxy-8(E)-octadecenoic acid production by recombinant cells co-expressing chaperone plasmid were pH 9, 35 °C, 15 % (v/v) dimethyl sulfoxide, 40 g cells l(-1), and 10 g oleic acid l(-1). Under these conditions, recombinant cells co-expressing chaperone plasmid produced 7.2 g 10S-hydroxy-8(E)-octadecenoic acid l(-1) within 30 min, with a conversion yield of 72 % (w/w) and a volumetric productivity of 14.4 g l(-1) h(-1). The activity of recombinant cells expressing 10S-dioxygenase was increased by 200 % with the aid of a chaperone, demonstrating the first biotechnological production of 10S-hydroxy-8(E)-octadecenoic acid using recombinant cells expressing 10S-dioxygenase.

  10. Faithful mRNA splicing depends on the Prp19 complex subunit faint sausage and is required for tracheal branching morphogenesis in Drosophila.

    Science.gov (United States)

    Sauerwald, Julia; Soneson, Charlotte; Robinson, Mark D; Luschnig, Stefan

    2017-02-15

    Morphogenesis requires the dynamic regulation of gene expression, including transcription, mRNA maturation and translation. Dysfunction of the general mRNA splicing machinery can cause surprisingly specific cellular phenotypes, but the basis for these effects is not clear. Here, we show that the Drosophila faint sausage (fas) locus, which is implicated in epithelial morphogenesis and has previously been reported to encode a secreted immunoglobulin domain protein, in fact encodes a subunit of the spliceosome-activating Prp19 complex, which is essential for efficient pre-mRNA splicing. Loss of zygotic fas function globally impairs the efficiency of splicing, and is associated with widespread retention of introns in mRNAs and dramatic changes in gene expression. Surprisingly, despite these general effects, zygotic fas mutants show specific defects in tracheal cell migration during mid-embryogenesis when maternally supplied splicing factors have declined. We propose that tracheal branching, which relies on dynamic changes in gene expression, is particularly sensitive for efficient spliceosome function. Our results reveal an entry point to study requirements of the splicing machinery during organogenesis and provide a better understanding of disease phenotypes associated with mutations in general splicing factors. © 2017. Published by The Company of Biologists Ltd.

  11. GHRH, PRP-PACAP and GHRHR Target Sequencing via an Ion Torrent Personal Genome Machine Reveals an Association with Growth in Orange-Spotted Grouper (Epinephelus coioides

    Directory of Open Access Journals (Sweden)

    Liang Guo

    2015-11-01

    Full Text Available Growth hormone-releasing hormone (GHRH and the receptor, GHRHR, constitute important components of the hypothalamus-pituitary growth axis and act on the downstream growth hormone (GH. PACAP-related peptide/pituitary adenylate cyclase activating polypeptide (PRP-PACAP is a paralog of GHRH. These genes all play key roles in development and growth patterns. To improve the quality of cultured fish strains, natural genetic variation must be examined and understood. A mixed linear model has been widely used in association mapping, taking the population structures and pairwise kinship patterns into consideration. In this study, a mass cross population of orange-spotted grouper (Epinephelus coioides was examined. These candidate genes were found to harbor low nucleotide diversity (θw from 0.00154 to 0.00388 and linkage disequilibrium levels (delay of 50% within 2 kbp. Association mapping was employed, and two single-nucleotide polymorphisms (KR269823.1:g.475A>C and KR269823.1:g.2143T>C were found to be associated with growth (false discovery rate Q < 0.05, explaining 9.0%–17.0% of the phenotypic variance. The association of KR269823.1:g.2143T>C was also found via haplotype-based association (p < 0.05. The identified associations offer new insights into gene functions, and the associated single-nucleotide polymorphisms (SNPs may be used for breeding purposes.

  12. The Role of Sigma-1 Receptor, an Intracellular Chaperone in Neurodegenerative Diseases.

    Science.gov (United States)

    Penke, Botond; Fülöp, Lívia; Szűcs, Mária; Frecska, Ede

    2017-05-28

    Widespread protein aggregation occurs in the living system under stress or during aging, owing to disturbance of endoplasmic reticulum (ER) proteostasis. Many neurodegenerative diseases may have a common mechanism: the failure of protein homeostasis. Perturbation of ER results in unfolded protein response (UPR). Prolonged chronical UPR may activate apoptotic pathways and cause cell death. ER is associated to mitochondria by the mitochondria-associated ER-membrane, MAM. The sigma-1 receptor (Sig-1R), a well-known ER-chaperone localizes in the MAM. It serves for Ca2+-signaling between the ER and mitochondria, involved in ion channel activities and especially important during neuronal differentiation. Sig-1R acts as central modulator in inter-organelle signaling. Sig-1R helps cell survival by attenuating ER-stress. According to sequence based predictions Sig-1R is a 223 amino acid protein with two transmembrane (2TM) domains. The X-ray structure of the Sig-1R [1] showed a membrane-bound trimeric assembly with one transmembrane (1TM) region. Despite the in vitro determined assembly, the results of in vivo studies are rather consistent with the 2TM structure . The receptor has unique and versatile pharmacological profile. Dimethyl tryptamine (DMT) and neuroactive steroids are endogenous ligands that activate Sig-1R. The receptor has a plethora of interacting client proteins. Sig-1R exists in oligomeric structures (dimer-trimer-octamer-multimer) and this fact may explain interaction with diverse proteins. Sig-1R agonists have been used in the treatment of different neurodegenerative diseases e.g. Alzheimer's and Parkinson's diseases (AD and PD) and amyotrophic lateral sclerosis. Utilization of Sig-1R agents early in AD and similar other diseases has remained an overlooked therapeutic opportunity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  13. Interplay between Molecular Chaperones and the Ubiquitin-Proteasome System in Targeting of Misfolded Proteins for Degradation

    DEFF Research Database (Denmark)

    Poulsen, Esben Guldahl

    interacting with purified 26S proteasomes, and the subsequent characterization of two novel proteasome interacting proteins. The third study was aimed at analyzing the chaperone-assisted pathway leading to degradation of misfolded kinetochore proteins in S. pombe. In this study chaperones, E2s, E3s and DUBs...

  14. Mechanisms of Translocation of ER Chaperones to the Cell Surface and Immunomodulatory Roles in Cancer and Autoimmunity

    NARCIS (Netherlands)

    Wiersma, Valerie; Michalak, Marek; Abdullah, Trefa M; Bremer, Edwin; Eggleton, Paul

    2015-01-01

    Endoplasmic reticulum (ER) chaperones (e.g., calreticulin, heat shock proteins, and isomerases) perform a multitude of functions within the ER. However, many of these chaperones can translocate to the cytosol and eventually the surface of cells, particularly during ER stress induced by e.g., drugs,

  15. Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture.

    Directory of Open Access Journals (Sweden)

    Ramazan Kurt

    Full Text Available Hepatic steatosis is a risk factor for both liver disease progression and an impaired response to interferon alpha (IFN-α-based combination therapy in chronic hepatitis C virus (HCV infection. Previously, we reported that free fatty acid (FFA-treated HCV cell culture induces hepatocellular steatosis and impairs the expression of interferon alpha receptor-1 (IFNAR1, which is why the antiviral activity of IFN-α against HCV is impaired.To investigate the molecular mechanism by which IFNAR1 expression is impaired in HCV cell culture with or without free fatty acid-treatment.HCV-infected Huh 7.5 cells were cultured with or without a mixture of saturated (palmitate and unsaturated (oleate long-chain free fatty acids (FFA. Intracytoplasmic fat accumulation in HCV-infected culture was visualized by oil red staining. Clearance of HCV in FFA cell culture treated with type I IFN (IFN-α and Type III IFN (IFN-λ was determined by Renilla luciferase activity, and the expression of HCV core was determined by immunostaining. Activation of Jak-Stat signaling in the FFA-treated HCV culture by IFN-α alone and IFN-λ alone was examined by Western blot analysis and confocal microscopy. Lysosomal degradation of IFNAR1 by chaperone-mediated autophagy (CMA in the FFA-treated HCV cell culture model was investigated.FFA treatment induced dose-dependent hepatocellular steatosis and lipid droplet accumulation in HCV-infected Huh-7.5 cells. FFA treatment of infected culture increased HCV replication in a concentration-dependent manner. Intracellular lipid accumulation led to reduced Stat phosphorylation and nuclear translocation, causing an impaired IFN-α antiviral response and HCV clearance. Type III IFN (IFN-λ, which binds to a separate receptor, induces Stat phosphorylation, and nuclear translocation as well as antiviral clearance in FFA-treated HCV cell culture. We show here that the HCV-induced autophagy response is increased in FFA-treated cell culture

  16. Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture.

    Science.gov (United States)

    Kurt, Ramazan; Chandra, Partha K; Aboulnasr, Fatma; Panigrahi, Rajesh; Ferraris, Pauline; Aydin, Yucel; Reiss, Krzysztof; Wu, Tong; Balart, Luis A; Dash, Srikanta

    2015-01-01

    Hepatic steatosis is a risk factor for both liver disease progression and an impaired response to interferon alpha (IFN-α)-based combination therapy in chronic hepatitis C virus (HCV) infection. Previously, we reported that free fatty acid (FFA)-treated HCV cell culture induces hepatocellular steatosis and impairs the expression of interferon alpha receptor-1 (IFNAR1), which is why the antiviral activity of IFN-α against HCV is impaired. To investigate the molecular mechanism by which IFNAR1 expression is impaired in HCV cell culture with or without free fatty acid-treatment. HCV-infected Huh 7.5 cells were cultured with or without a mixture of saturated (palmitate) and unsaturated (oleate) long-chain free fatty acids (FFA). Intracytoplasmic fat accumulation in HCV-infected culture was visualized by oil red staining. Clearance of HCV in FFA cell culture treated with type I IFN (IFN-α) and Type III IFN (IFN-λ) was determined by Renilla luciferase activity, and the expression of HCV core was determined by immunostaining. Activation of Jak-Stat signaling in the FFA-treated HCV culture by IFN-α alone and IFN-λ alone was examined by Western blot analysis and confocal microscopy. Lysosomal degradation of IFNAR1 by chaperone-mediated autophagy (CMA) in the FFA-treated HCV cell culture model was investigated. FFA treatment induced dose-dependent hepatocellular steatosis and lipid droplet accumulation in HCV-infected Huh-7.5 cells. FFA treatment of infected culture increased HCV replication in a concentration-dependent manner. Intracellular lipid accumulation led to reduced Stat phosphorylation and nuclear translocation, causing an impaired IFN-α antiviral response and HCV clearance. Type III IFN (IFN-λ), which binds to a separate receptor, induces Stat phosphorylation, and nuclear translocation as well as antiviral clearance in FFA-treated HCV cell culture. We show here that the HCV-induced autophagy response is increased in FFA-treated cell culture

  17. glsA, a Volvox gene required for asymmetric division and germ cell specification, encodes a chaperone-like protein.

    Science.gov (United States)

    Miller, S M; Kirk, D L

    1999-02-01

    The gls genes of Volvox are required for the asymmetric divisions that set apart cells of the germ and somatic lineages during embryogenesis. Here we used transposon tagging to clone glsA, and then showed that it is expressed maximally in asymmetrically dividing embryos, and that it encodes a 748-amino acid protein with two potential protein-binding domains. Site-directed mutagenesis of one of these, the J domain (by which Hsp40-class chaperones bind to and activate specific Hsp70 partners) abolishes the capacity of glsA to rescue mutants. Based on this and other considerations, including the fact that the GlsA protein is associated with the mitotic spindle, we discuss how it might function, in conjunction with an Hsp70-type partner, to shift the division plane in asymmetrically dividing cells.

  18. Cloning, expression and nuclear localization of human NPM3, a member of the nucleophosmin/nucleoplasmin family of nuclear chaperones

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    Ganguly Amit

    2001-11-01

    Full Text Available Abstract Background Studies suggest that the related proteins nucleoplasmin and nucleophosmin (also called B23, NO38 or numatrin are nuclear chaperones that mediate the assembly of nucleosomes and ribosomes, respectively, and that these activities are accomplished through the binding of basic proteins via their acidic domains. Recently discovered and less well characterized members of this family of acidic phosphoproteins include mouse nucleophosmin/nucleoplasmin 3 (Npm3 and Xenopus NO29. Here we report the cloning and initial characterization of the human ortholog of Npm3. Results Human genomic and cDNA clones of NPM3 were isolated and sequenced. NPM3 lies 5.5 kb upstream of FGF8 and thus maps to chromosome 10q24-26. In addition to amino acid similarities, NPM3 shares many physical characteristics with the nucleophosmin/nucleoplasmin family, including an acidic domain, multiple potential phosphorylation sites and a putative nuclear localization signal. Comparative analyses of 14 members of this family from various metazoans suggest that Xenopus NO29 is a candidate ortholog of human and mouse NPM3, and they further group both proteins closer with the nucleoplasmins than with the nucleophosmins. Northern blot analysis revealed that NPM3 was strongly expressed in all 16 human tissues examined, with especially robust expression in pancreas and testis; lung displayed the lowest level of expression. An analysis of subcellular fractions of NIH3T3 cells expressing epitope-tagged NPM3 revealed that NPM3 protein was localized solely in the nucleus. Conclusions Human NPM3 is an abundant and widely expressed protein with primarily nuclear localization. These biological activities, together with its physical relationship to the chaparones nucleoplasmin and nucleophosmin, are consistent with the proposed function of NPM3 as a molecular chaperone functioning in the nucleus.

  19. PrP glycoforms are associated in a strain-specific ratio in native PrPSc.

    Science.gov (United States)

    Khalili-Shirazi, Azadeh; Summers, Linda; Linehan, Jacqueline; Mallinson, Gary; Anstee, David; Hawke, Simon; Jackson, Graham S; Collinge, John

    2005-09-01

    Prion diseases involve conversion of host-encoded cellular prion protein (PrPC) to a disease-related isoform (PrPSc). Using recombinant human beta-PrP, a panel of monoclonal antibodies was produced that efficiently immunoprecipitated native PrPSc and recognized epitopes between residues 93-105, indicating for the first time that this region is exposed in both human vCJD and mouse RML prions. In contrast, monoclonal antibodies raised to human alpha-PrP were more efficient in immunoprecipitating PrPC than PrPSc, and some of them could also distinguish between different PrP glycoforms. Using these monoclonal antibodies, the physical association of PrP glycoforms was studied in normal brain and in the brains of humans and mice with prion disease. It was shown that while PrPC glycoforms can be selectively immunoprecipitated, the differentially glycosylated molecules of native PrPSc are closely associated and always immunoprecipitate together. Furthermore, the ratio of glycoforms comprising immunoprecipitated native PrPSc from diverse prion strains was similar to those observed on denaturing Western blots. These studies are consistent with the view that the proportion of each glycoform incorporated into PrPSc is probably controlled in a strain-specific manner and that each PrPSc particle contains a mixture of glycoforms.

  20. L-PRP/L-PRF in esthetic plastic surgery, regenerative medicine of the skin and chronic wounds.

    Science.gov (United States)

    Cieslik-Bielecka, Agata; Choukroun, Joseph; Odin, Guillaume; Dohan Ehrenfest, David M

    2012-06-01

    The use of platelet concentrates for topical use is of particular interest for the promotion of skin wound healing. Fibrin-based surgical adjuvants are indeed widely used in plastic surgery since many years in order to improve scar healing and wound closure. However, the addition of platelets and their associated growth factors opened a new range of possibilities, particularly for the treatment of chronic skin ulcers and other applications of regenerative medicine on the covering tissues. In the 4 families of platelet concentrates available, 2 families were particularly used and tested in this clinical field: L-PRP (Leukocyte- and Platelet-rich Plasma) and L-PRF (Leukocyte- and Platelet-Rich Fibrin). These 2 families have in common the presence of significant concentrations of leukocytes, and these cells are important in the local cleaning and immune regulation of the wound healing process. The main difference between them is the fibrin architecture, and this parameter considerably influences the healing potential and the therapeutical protocol associated to each platelet concentrate technology. In this article, we describe the historical evolutions of these techniques from the fibrin glues to the current L-PRP and L-PRF, and discuss the important functions of the platelet growth factors, the leukocyte content and the fibrin architecture in order to optimize the numerous potential applications of these products in regenerative medicine of the skin. Many outstanding perspectives are appearing in this field and require further research.

  1. Assessment of efficacy of platelet-rich plasma (PRP) on infraorbital dark circles and crow's feet wrinkles.

    Science.gov (United States)

    Mehryan, Pedram; Zartab, Hamed; Rajabi, Ali; Pazhoohi, Neda; Firooz, Alireza

    2014-03-01

    Infraorbital skin hyperpigmentation, commonly called dark circles, and crow's feet wrinkles are common cosmetic concerns. Various methods of treatment have been evaluated with variable outcomes. This study was performed to assess the efficacy of platelet-rich plasma (PRP) injection for treating periorbital dark circles and crow's feet. Ten participants with a mean age of 41.2 years were treated in a single session with intradermal injections of 1.5 mL PRP into tear trough area and crow's feet wrinkles on each side. The effects on melanin content, color homogeneity of the treated area, epidermal stratum corneum hydration, and wrinkle volume and visibility index were compared 3 months after treatment with baseline. Physician's global assessment and participants' satisfaction and any potential side effects were also assessed. The improvement in infraorbital color homogeneity was statistically significant (P = 0.010), but no statistically significant changes were observed in melanin content, stratum corneum hydration, wrinkle volume, and visibility index. Participant's satisfaction score and physician's global assessment score were 2.2 and 1.7, respectively, on a 0-3 scale. Platelet-rich plasma may have the potential to improve infraorbital dark circle in terms of color homogeneity of the region, though this remains to be proven using larger, controlled studies using multiple injections. © 2014 Wiley Periodicals, Inc.

  2. Proteomics analysis of exported chaperone/co-chaperone complexes of P. falciparum reveals an array of complex protein-protein interactions

    OpenAIRE

    Zhang, Qi; Przyborski, Jude (Prof. Dr.)

    2016-01-01

    In order to grow and survive the human malaria parasite Plasmodium falciparum synthesizes and exports hundreds of proteins in order to modify the infected red blood cell. In previous studies, our group found that two members of parasite encoded type II Hsp40s (PEF55, PFA660) associate with highly mobile structure in the infected host cell, which are referred to as J-dots. Furthermore, an exported parasite chaperone, PfHsp70x was i...

  3. Eps8 is recruited to lysosomes and subjected to chaperone-mediated autophagy in cancer cells.

    Science.gov (United States)

    Welsch, Thilo; Younsi, Alexander; Disanza, Andrea; Rodriguez, Jose Antonio; Cuervo, Ana Maria; Scita, Giorgio; Schmidt, Jan

    2010-07-15

    Eps8 controls actin dynamics directly through its barbed end capping and actin-bundling activity, and indirectly by regulating Rac-activation when engaged into a trimeric complex with Eps8-Abi1-Sos1. Recently, Eps8 has been associated with promotion of various solid malignancies, but neither its mechanisms of action nor its regulation in cancer cells have been elucidated. Here, we report a novel association of Eps8 with the late endosomal/lysosomal compartment, which is independent from actin polymerization and specifically occurs in cancer cells. Endogenous Eps8 localized to large vesicular lysosomal structures in metastatic pancreatic cancer cell lines, such as AsPC-1 and Capan-1 that display high Eps8 levels. Additionally, ectopic expression of Eps8 increased the size of lysosomes. Structure-function analysis revealed that the region encompassing the amino acids 184-535 of Eps8 was sufficient to mediate lysosomal recruitment. Notably, this fragment harbors two KFERQ-like motifs required for chaperone-mediated autophagy (CMA). Furthermore, Eps8 co-immunoprecipitated with Hsc70 and LAMP-2, which are key elements for the CMA degradative pathway. Consistently, in vitro, a significant fraction of Eps8 bound to (11.9+/-5.1%) and was incorporated into (5.3+/-6.5%) lysosomes. Additionally, Eps8 binding to lysosomes was competed by other known CMA-substrates. Fluorescence recovery after photobleaching revealed that Eps8 recruitment to the lysosomal membrane was highly dynamic. Collectively, these results indicate that Eps8 in certain human cancer cells specifically localizes to lysosomes, and is directed to CMA. These results open a new field for the investigation of how Eps8 is regulated and contributes to tumor promotion in human cancers.

  4. Exosomes derived from platelet-rich plasma promote the re-epithelization of chronic cutaneous wounds via activation of YAP in a diabetic rat model.

    Science.gov (United States)

    Guo, Shang-Chun; Tao, Shi-Cong; Yin, Wen-Jing; Qi, Xin; Yuan, Ting; Zhang, Chang-Qing

    2017-01-01

    Chronic wounds have become an economic, social, and public health burden and need advanced treatment. Platelet-rich plasma (PRP) has been used extensively in treatment of chronic wounds because it contains an abundance of growth factors secreted by platelets. The exosomes derived from PRP (PRP-Exos) have been proven to encapsulate principal growth factors from platelets. This study is the first to show that these exosomes may exert the function of PRP. PRP-Exos can effectively induce proliferation and migration of endothelial cells and fibroblasts to improve angiogenesis and re-epithelialization in chronic wounds. We regulated YAP to verify the PRP-Exos-dependent effect on fibroblast proliferation and migration through YAP activation. In vivo, we observed the cutaneous healing process in chronic wounds treated with PRP-Exos in a diabetic rat model. We provide evidence of the probable molecular mechanisms underlying the PRP effect on healing of chronic ulcers and describe a promising resource of growth factors from exosomes without species restriction.

  5. PrP(ST, a soluble, protease resistant and truncated PrP form features in the pathogenesis of a genetic prion disease.

    Directory of Open Access Journals (Sweden)

    Yael Friedman-Levi

    Full Text Available While the conversion of PrP(C into PrP(Sc in the transmissible form of prion disease requires a preexisting PrP(Sc seed, in genetic prion disease accumulation of disease related PrP could be associated with biochemical and metabolic modifications resulting from the designated PrP mutation. To investigate this possibility, we looked into the time related changes of PrP proteins in the brains of TgMHu2ME199K/wt mice, a line modeling for heterozygous genetic prion disease linked to the E200K PrP mutation. We found that while oligomeric entities of mutant E199KPrP exist at all ages, aggregates of wt PrP in the same brains presented only in advanced disease, indicating a late onset conversion process. We also show that most PK resistant PrP in TgMHu2ME199K mice is soluble and truncated (PrP(ST, a pathogenic form never before associated with prion disease. We next looked into brain samples from E200K patients and found that both PK resistant PrPs, PrP(ST as in TgMHu2ME199K mice, and "classical" PrP(Sc as in infectious prion diseases, coincide in the patient's post mortem brains. We hypothesize that aberrant metabolism of mutant PrPs may result in the formation of previously unknown forms of the prion protein and that these may be central for the fatal outcome of the genetic prion condition.

  6. Virus-Induced Chaperone-Enriched (VICE domains function as nuclear protein quality control centers during HSV-1 infection.

    Directory of Open Access Journals (Sweden)

    Christine M Livingston

    2009-10-01

    Full Text Available Virus-Induced Chaperone-Enriched (VICE domains form adjacent to nuclear viral replication compartments (RC during the early stages of HSV-1 infection. Between 2 and 3 hours post infection at a MOI of 10, host protein quality control machinery such as molecular chaperones (e.g. Hsc70, the 20S proteasome and ubiquitin are reorganized from a diffuse nuclear distribution pattern to sequestration in VICE domains. The observation that VICE domains contain putative misfolded proteins suggests that they may be similar to nuclear inclusion bodies that form under conditions in which the protein quality control machinery is overwhelmed by the presence of misfolded proteins. The detection of Hsc70 in VICE domains, but not in nuclear inclusion bodies, indicates that Hsc70 is specifically reorganized by HSV-1 infection. We hypothesize that HSV-1 infection induces the formation of nuclear protein quality control centers to remodel or degrade aberrant nuclear proteins that would otherwise interfere with productive infection. Detection of proteolytic activity in VICE domains suggests that substrates may be degraded by the 20S proteasome in VICE domains. FRAP analysis reveals that GFP-Hsc70 is dynamically associated with VICE domains, suggesting a role for Hsc70 in scanning the infected nucleus for misfolded proteins. During 42 degrees C heat shock, Hsc70 is redistributed from VICE domains into RC perhaps to remodel viral replication and regulatory proteins that have become insoluble in these compartments. The experiments presented in this paper suggest that VICE domains are nuclear protein quality control centers that are modified by HSV-1 to promote productive infection.

  7. Nucleosome assembly protein-1 is a linker histone chaperone in Xenopus eggs.

    Science.gov (United States)

    Shintomi, Keishi; Iwabuchi, Mari; Saeki, Hideaki; Ura, Kiyoe; Kishimoto, Takeo; Ohsumi, Keita

    2005-06-07

    In eukaryotic cells, genomic DNA is primarily packaged into nucleosomes through sequential ordered binding of the core and linker histone proteins. The acidic proteins termed histone chaperones are known to bind to core histones to neutralize their positive charges, thereby facilitating their proper deposition onto DNA to assemble the core of nucleosomes. For linker histones, however, little has been known about the regulatory mechanism for deposition of linker histones onto the linker DNA. Here we report that, in Xenopus eggs, the linker histone is associated with the Xenopus homologue of nucleosome assembly protein-1 (NAP-1), which is known to be a chaperone for the core histones H2A and H2B in Drosophila and mammalian cells [Ito, T., Bulger, M., Kobayashi, R. & Kadonaga, J. T. (1996) Mol. Cell Biol. 16, 3112-3124; Chang, L., Loranger, S. S., Mizzen, C., Ernst, S. G., Allis, C. D. & Annunziato, A. T. (1997) Biochemistry 36, 469-480]. We show that NAP-1 acts as the chaperone for the linker histone in both sperm chromatin remodeling into nucleosomes and linker histone binding to nucleosome core dimers. In the presence of NAP-1, the linker histone is properly deposited onto linker DNA at physiological ionic strength, without formation of nonspecific aggregates. These results strongly suggest that NAP-1 functions as a chaperone for the linker histone in Xenopus eggs.

  8. Co-translational capturing of nascent ribosomal proteins by their dedicated chaperones

    Science.gov (United States)

    Pausch, Patrick; Singh, Ujjwala; Ahmed, Yasar Luqman; Pillet, Benjamin; Murat, Guillaume; Altegoer, Florian; Stier, Gunter; Thoms, Matthias; Hurt, Ed; Sinning, Irmgard; Bange, Gert; Kressler, Dieter

    2015-06-01

    Exponentially growing yeast cells produce every minute >160,000 ribosomal proteins. Owing to their difficult physicochemical properties, the synthesis of assembly-competent ribosomal proteins represents a major challenge. Recent evidence highlights that dedicated chaperone proteins recognize the N-terminal regions of ribosomal proteins and promote their soluble expression and delivery to the assembly site. Here we explore the intuitive possibility that ribosomal proteins are captured by dedicated chaperones in a co-translational manner. Affinity purification of four chaperones (Rrb1, Syo1, Sqt1 and Yar1) selectively enriched the mRNAs encoding their specific ribosomal protein clients (Rpl3, Rpl5, Rpl10 and Rps3). X-ray crystallography reveals how the N-terminal, rRNA-binding residues of Rpl10 are shielded by Sqt1's WD-repeat β-propeller, providing mechanistic insight into the incorporation of Rpl10 into pre-60S subunits. Co-translational capturing of nascent ribosomal proteins by dedicated chaperones constitutes an elegant mechanism to prevent unspecific interactions and aggregation of ribosomal proteins on their road to incorporation.

  9. Hsp40 function in yeast prion propagation: Amyloid diversity necessitates chaperone functional complexity.

    Science.gov (United States)

    Sporn, Zachary A; Hines, Justin K

    2015-01-01

    Yeast prions are heritable protein-based elements, most of which are formed of amyloid aggregates that rely on the action of molecular chaperones for transmission to progeny. Prions can form distinct amyloid structures, known as 'strains' in mammalian systems, that dictate both pathological progression and cross-species infection barriers. In yeast these same amyloid structural polymorphisms, called 'variants', dictate the intensity of prion-associated phenotypes and stability in mitosis. We recently reported that [PSI(+)] prion variants differ in the fundamental domain requirements for one chaperone, the Hsp40/J-protein Sis1, which are mutually exclusive between 2 different yeast prions, demonstrating a functional plurality for Sis1. Here we extend that analysis to incorporate additional data that collectively support the hypothesis that Sis1 has multiple functional roles that can be accomplished by distinct sets of domains. These functions are differentially required by distinct prions and prion variants. We also present new data regarding Hsp104-mediated prion elimination and show that some Sis1 functions, but not all, are conserved in the human homolog Hdj1/DNAJB1. Importantly, of the 10 amyloid-based prions indentified to date in Saccharomyces cerevisiae, the chaperone requirements of only 4 are known, leaving a great diversity of amyloid structures, and likely modes of amyloid-chaperone interaction, largely unexplored.

  10. Chaperone gelator for the chiral self-assembly of all proteinogenic amino acids and their enantiomers.

    Science.gov (United States)

    Chen, Jie; Wang, Tianyu; Liu, Minghua

    2016-05-04

    A concept of a chaperone gelator that can assist non-gelator molecules to form gels is proposed. Such a new gelator was developed and found to tune all the proteinogenic l-amino acids, as well as their enantiomers into supramolecular gels.

  11. Histone Chaperone NAP1 Mediates Sister Chromatid Resolution by Counteracting Protein Phosphatase 2A

    NARCIS (Netherlands)

    Y.M. Moshkin (Yuri); C.M. Doyen (Cécile); T.W. Kan (Tsung Wai); G.E. Chalkley (Gillian); K. Sap (Karen); K. Bezstarosti (Karel); J.A.A. Demmers (Jeroen); Z. Özgür (Zeliha); W.F.J. van IJcken (Wilfred); C.P. Verrijzer (Peter)

    2013-01-01

    textabstractChromosome duplication and transmission into daughter cells requires the precisely orchestrated binding and release of cohesin. We found that the Drosophila histone chaperone NAP1 is required for cohesin release and sister chromatid resolution during mitosis. Genome-wide surveys revealed

  12. The Attitudes and Practices of General Practitioners about the Use of Chaperones in Melbourne, Australia

    Directory of Open Access Journals (Sweden)

    Oliver van Hecke

    2012-01-01

    Full Text Available Introduction. To consider the use of medical chaperones during certain clinical examinations is important whether one practises as a specialist, nurse, medical student, or generalist. Chaperones have been used by doctors conducting intimate examinations for many years but their true extent remains largely unknown. Until recently, there was no national guidance in Australia. Aim. To explore the attitudes and practices of general practitioners (GP regarding their use of chaperones in urban Melbourne, Australia. Method. Qualitative two focus groups involving seventeen GPs from two locations. Discussions were audio-taped, transcribed verbatim and analysed. Results. Common themes and subthemes emerged which were grouped into three main areas: (a practitioner-related, (b patient-related and (c practice related. Discussion. This is the first study from an Australian primary care perspective to gauge the attitudes and experiences of GPs on their use of chaperones. It will provide vital information to inform the next step of extending this research to a national GP audience. From an international perspective, this study provides an excellent template for other primary care clinicians to conduct research in this important field of doctor-patient relationship.

  13. Oral pharmacological chaperone migalastat compared with enzyme replacement therapy in Fabry disease

    DEFF Research Database (Denmark)

    Hughes, Derralynn A.; Nicholls, Kathleen; Shankar, Suma P.

    2017-01-01

    Background Fabry disease is an X-linked lysosomal storage disorder caused by GLA mutations, resulting in α-galactosidase (α-Gal) deficiency and accumulation of lysosomal substrates. Migalastat, an oral pharmacological chaperone being developed as an alternative to intravenous enzyme replacement t...

  14. Analytical background and discussion of the chaperone model of prion diseases.

    Science.gov (United States)

    Liautard, J P

    1999-01-01

    It is generally accepted that prion infection is due solely to a protein i.e. the protein-only hypothesis. The essential constituent of infectious prions is the scrapie prion protein (PrPSc) which is chemically indistinguishable from the normal, cellular protein (PrPC) but exhibits distinct secondary and tertiary structure. This very unusual feature seems to be in contradiction with a major paradigm of present structural biology stated by Anfinsen: a protein folds to the most stable conformation, this means only one structure. In order to reconcile the results obtained on prions with the biophysics of protein folding, a model is proposed. It is based on the hypothesis that a thermodynamically irreversible step is involved in protein folding. The model is then extended to chaperone-assisted protein folding. It is shown that, under certain conditions, the transitory secondary structure formed during the earlier step of folding could interact with chaperone. Analysis shows that chaperone may help the protein to find correct conformation. On the other hand, analysis reveals the possibility that more than one structure may form from a single polypeptide chain. Under these conditions, the behaviour of chaperones resembles the characteristics of prion diseases.

  15. Chaperone-usher fimbriae in a diverse selection of Gallibacterium genomes

    DEFF Research Database (Denmark)

    Kudirkiene, Egle; Bager, Ragnhild Jørgensen; Johnson, Timothy J.

    2014-01-01

    encoding a putative major fimbrial subunit, a chaperone, an usher and a fimbrial adhesin. Five fimbrial clusters (Flf-Flf4) and eight conserved domain groups were defined to accommodate the identified fimbriae. Although, the number of different fimbrial clusters in individual Gallibacterium genomes was low...

  16. The story of stolen chaperones: how overexpression of Q/N proteins cures yeast prions.

    Science.gov (United States)

    Derkatch, Irina L; Liebman, Susan W

    2013-01-01

    Prions are self-seeding alternate protein conformations. Most yeast prions contain glutamine/asparagine (Q/N)-rich domains that promote the formation of amyloid-like prion aggregates. Chaperones, including Hsp104 and Sis1, are required to continually break these aggregates into smaller "seeds." Decreasing aggregate size and increasing the number of growing aggregate ends facilitates both aggregate transmission and growth. Our previous work showed that overexpression of 11 proteins with Q/N-rich domains facilitates the de novo aggregation of Sup35 into the [PSI(+)] prion, presumably by a cross-seeding mechanism. We now discuss our recent paper, in which we showed that overexpression of most of these same 11 Q/N-rich proteins, including Pin4C and Cyc8, destabilized pre-existing Q/N rich prions. Overexpression of both Pin4C and Cyc8 caused [PSI(+)] aggregates to enlarge. This is incompatible with a previously proposed "capping" model where the overexpressed Q/N-rich protein poisons, or "caps," the growing aggregate ends. Rather the data match what is expected of a reduction in prion severing by chaperones. Indeed, while Pin4C overexpression does not alter chaperone levels, Pin4C aggregates sequester chaperones away from the prion aggregates. Cyc8 overexpression cures [PSI(+)] by inducing an increase in Hsp104 levels, as excess Hsp104 binds to [PSI(+)] aggregates in a way that blocks their shearing.

  17. Platelets display potent antimicrobial activity and release human beta-defensin 2.

    Science.gov (United States)

    Tohidnezhad, Mersedeh; Varoga, Deike; Wruck, Christoph Jan; Podschun, Rainer; Sachweh, Benita Hermanns; Bornemann, Jorg; Bovi, Manfred; Sönmez, Taha Tolga; Slowik, Alexander; Houben, Astrid; Seekamp, Andreas; Brandenburg, Lars Ove; Pufe, Thomas; Lippross, Sebastian

    2012-01-01

    Platelet-rich plasma (PRP) is a potent agent that improves soft tissue and bone healing. By the release of growth factors and cytokines, PRP is believed to locally boost physiologic healing processes. Recently, antimicrobial activity of PRP has been demonstrated against S. aureus strains. Major scientific effort is being put into the understanding and prevention of infections i.e. by delivery of antimicrobial substances. In previous studies we showed the ideal antibacterial activity-profile of the human beta-defensin 2 (hBD-2) for orthopaedic infections and therefore hypothesized that hBD-2 may be the effector of antimicrobial platelet action. Platelet concentrates were produced from human platelet phresis obtained from a hospital blood bank. They were screened by immunohistochemistry, Western Blot and ELISA for the human beta defensin-2. In vitro susceptibility to PRP was investigated by a standard disc diffusion test with or without pre-incubation of PRP with anti-hBD-2 antibody. SPSS statistical software was used for statistical analysis. PRP contains hBD-2 470 pg/10(9) platelets or 1786 pg/ml, respectively, (ELISA), which was confirmed by immunohistochemistry and Western Blot. In antimicrobial testing, PRP demonstrates effective inhibition of E. coli, B. megaterium, P. aeruginosa, E. faecalis and P. mirabilis. With this study we confirm the previously reported antimicrobial action of platelet concentrates i.e. PRP. In opposition to previously reported effects against gram positive bacteria our study focuses on gram negative and less common gram positive bacteria that do frequently cause clinical complications. We provide a possible molecular mechanism at least for E. coli and P. mirabilis for this effect by the detection of an antimicrobial peptide (hBD-2). This study may advocate the clinical use of PRP by highlighting a new aspect of platelet action.

  18. Fibroblastic synoviocytes secrete plasma proteins via α2 -macroglobulins serving as intracellular and extracellular chaperones.

    Science.gov (United States)

    Zhao, Ke-Wei; Murray, Elsa J Brochmann; Murray, Samuel S

    2015-11-01

    Changes in plasma protein levels in synovial fluid (SF) have been implicated in osteoarthritis and rheumatoid arthritis. It was previously thought that the presence of plasma proteins in SF reflected ultrafiltration or extravasation from the vasculature, possibly due to retraction of inflamed endothelial cells. Recent proteomic analyses have confirmed the abundant presence of plasma proteins in SF from control and arthritic patients. Systematic depletion of high-abundance plasma proteins from SF and conditioned media from synoviocytes cultured in serum, and protein analysis under denaturing/reducing conditions have limited our understanding of sources and the native structures of "plasma protein" complexes in SF. Using Western blotting, qPCR, and mass spectrometry, we found that Hig-82 lapine fibroblastic synovicytes cultured under serum-free conditions expressed and secreted plasma proteins, including the cytokine-binding protein secreted phosphoprotein 24 kDa (Spp24) and many of the proteases and protease inhibitors found in SF. Treating synoviocytes with TGF-β1 or BMP-2 for 24 h upregulated the expression of plasma proteins, including Spp24, α2 -HS-glycoprotein, α1 -antitrypsin, IGF-1, and C-reactive protein. Furthermore, many of the plasma proteins of mass <151 kDa were secreted as disulfide-bound complexes with members of the α2 -macroglobulin (A2M) family, which serve as intracellular and extracellular chaperones, not protease inhibitors. Using brefeldin A to block vesicular traffic and protease inhibitors to inhibit endogenous activation of naïve A2M, we demonstrated that the complexes were formed in the endoplasmic reticulum lumen and that Ca(2+) cysteine protease-dependent processes are involved. © Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  19. The RNA chaperone Hfq impacts growth, metabolism and production of virulence factors in Yersinia enterocolitica.

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    Tamara Kakoschke

    Full Text Available To adapt to changes in environmental conditions, bacteria regulate their gene expression at the transcriptional but also at the post-transcriptional level, e.g. by small RNAs (sRNAs which modulate mRNA stability and translation. The conserved RNA chaperone Hfq mediates the interaction of many sRNAs with their target mRNAs, thereby playing a global role in fine-tuning protein production. In this study, we investigated the significance of Hfq for the enteropathogen Yersina enterocolitica serotype O:8. Hfq facilitated optimal growth in complex and minimal media. Our comparative protein analysis of parental and hfq-negative strains suggested that Hfq promotes lipid metabolism and transport, cell redox homeostasis, mRNA translation and ATP synthesis, and negatively affects carbon and nitrogen metabolism, transport of siderophore and peptides and tRNA synthesis. Accordingly, biochemical tests indicated that Hfq represses ornithine decarboxylase activity, indole production and utilization of glucose, mannitol, inositol and 1,2-propanediol. Moreover, Hfq repressed production of the siderophore yersiniabactin and its outer membrane receptor FyuA. In contrast, hfq mutants exhibited reduced urease production. Finally, strains lacking hfq were more susceptible to acidic pH and oxidative stress. Unlike previous reports in other Gram-negative bacteria, Hfq was dispensable for type III secretion encoded by the virulence plasmid. Using a chromosomally encoded FLAG-tagged Hfq, we observed increased production of Hfq-FLAG in late exponential and stationary phases. Overall, Hfq has a profound effect on metabolism, resistance to stress and modulates the production of two virulence factors in Y. enterocolitica, namely urease and yersiniabactin.

  20. Oxidative stress induces monocyte necrosis with enrichment of cell-bound albumin and overexpression of endoplasmic reticulum and mitochondrial chaperones.

    Directory of Open Access Journals (Sweden)

    Haiping Tang

    Full Text Available In the present study, monocytes were treated with 5-azacytidine (azacytidine, gossypol or hydrogen peroxide to induce cell death through oxidative stress. A shift from apoptotic to necrotic cell death occurred when monocytes were treated with 100 µM azacytidine for more than 12 hours. Necrotic monocytes exhibited characteristics, including enrichment of cell-bound albumin and up-regulation of endoplasmic reticulum (ER- and mitochondrial-specific chaperones to protect mitochondrial integrity, which were not observed in other necrotic cells, including HUH-7, A2780, A549 and HOC1a. Our results show that the cell-bound albumin originates in the culture medium rather than from monocyte-derived hepatocytes, and that HSP60 is a potential binding partner of the cell-bound albumin. Proteomic analysis shows that HSP60 and protein disulfide isomerase are the most abundant up-regulated mitochondrial and ER-chaperones, and that both HSP60 and calreticulin are ubiquitinated in necrotic monocytes. In contrast, expression levels of the cytosolic chaperones HSP90 and HSP71 were down-regulated in the azacytidine-treated monocytes, concomitant with an increase in the levels of these chaperones in the cell culture medium. Collectively, our results demonstrates that chaperones from different organelles behave differently in necrotic monocytes, ER- and mitochondrial chaperones being retained and cytosolic and nuclear chaperones being released into the cell culture medium through the ruptured cell membrane. HSP60 may serve as a new target for development of myeloid leukemia treatment.

  1. Protecting effect of PrP codons M142 and K222 in goats orally challenged with bovine spongiform encephalopathy prions

    NARCIS (Netherlands)

    Fast, C.; Goldmann, W.; Berthon, P.; Tauscher, Kerstin; Andréoletti, O.; Lantier, I.; Rossignol, C.; Bossers, A.; Jacobs, J.G.; Hunter, N.; Groschup, Martin H.; Lantier, F.; Langeveld, J.P.M.

    2017-01-01

    Breeding towards genetic resistance to prion disease is effective in eliminating scrapie. In sheep, classical forms of scrapie have been eradicated almost completely in several countries by breeding programs using a prion protein (PrP) gene (PRNP) amino acid polymorphism. For goats, field and

  2. PrP0\\0 mice show behavioral abnormalities that suggest PrPC has a role in maintaining the cytoskeleton.

    Science.gov (United States)

    Background/Introduction. PrPC is highly conserved among mammals, but its natural function is unclear. Prnp ablated mice (PrP0/0) appear to develop normally and are able to reproduce. These observations seem to indicate that the gene is not essential for viability, in spite of it being highly conse...

  3. Multi-center study on the simultaneous administration of DPT-IPV and Hib PRP-T vaccines. Part 1. Immunogenicity

    NARCIS (Netherlands)

    Labadie J; Sundermann LC; Rumke HC; the DPT-IPV Hib vaccine study group; LVO; LVM; LCB; LBA; LPO

    1996-01-01

    Results are presented of a multi-center clinical study into the antibody formation following two vaccination regimens with simultaneous and combined administration of DPT-IPV and Hib PRP-T vaccines. 543 infants were recruited from 42 baby clinics in Apeldoorn, Capelle and Rotterdam. The antibody

  4. Effectiveness of polyene antibiotics in treatment of transmissible spongiform encephalopathy in transgenic mice expressing Syrian hamster PrP only in neurons.

    Science.gov (United States)

    Demaimay, R; Race, R; Chesebro, B

    1999-04-01

    To date very few drugs have favorably influenced the course of transmissible spongiform encephalopathies. In previous studies, the polyene antibiotics amphotericin B (AmB) and MS-8209 prolonged the incubation time in Syrian hamsters of the 263K strain of scrapie, but AmB had no effect against other scrapie strains in Syrian hamsters. In the present experiments using transgenic mice expressing Syrian hamster PrP in neurons only, MS-8209 extended the life spans of animals infected with the 263K strain but not the DY strain. AmB was effective against both 263K and DY and prevented death in 18% of DY-infected animals. The AmB effect against strain 263K was more prominent in mice whose endogenous PrP gene had been inactivated by homologous recombination. It was unclear whether this difference was due to a change in the duration of the disease or to possible interactive effects between the mouse PrP gene and the drugs themselves. The effectiveness of treatment after intracerebral scrapie infection in transgenic mice expressing PrP only in neurons suggested that neurons are important sites of action for these drugs.

  5. Histone Chaperone Jun Dimerization Protein 2 (JDP2: Role in Cellular Senescence and Aging

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    Yu-Chang Huang

    2010-10-01

    Full Text Available Transcription factor Jun dimerization protein 2 (JDP2 binds directly to histones and DNA, and inhibits p300-mediated acetylation of core histones and reconstituted nucleosomes that contain JDP2-recognition DNA sequences. The region of JDP2 that encompasses its histone-binding domain and DNA-binding region is essential to inhibit histone acetylation by histone acetyltransferases. Moreover, assays of nucleosome assembly in vitro demonstrate that JDP2 also has histone-chaperone activity. The mutation of the region responsible for inhibition of histone acetyltransferase activity within JDP2 eliminates repression of transcription from the c-jun promoter by JDP2, as well as JDP2-mediated inhibition of retinoic-acid-induced differentiation. Thus JDP2 plays a key role as a repressor of cell differentiation by regulating the expression of genes with an activator protein 1 (AP-1 site via inhibition of histone acetylation and/or assembly and disassembly of nucleosomes. Senescent cells show a series of alterations, including flatten and enlarged morphology, increase in nonspecific acidic β-galactosidase activity, chromatin condensation, and changes in gene expression patterns. The onset and maintenance of senescence are regulated by two tumor suppressors, p53 and retinoblastoma proteins. The expression of p53 and retinoblastoma proteins is regulated by two distinct proteins, p16Ink4a and Arf, respectively, which are encoded by cdkn2a. JDP2 inhibits recruitment of the polycomb repressive complexes 1 and 2 (PRC-1 and PRC-2 to the promoter of the gene that encodes p16Ink4a and inhibits the methylation of lysine 27 of histone H3 (H3K27. The PRCs associate with the p16Ink4a/Arf locus in young proliferating cells and dissociate from it in senescent cells. Therefore, it seems that chromatin-remodeling factors that regulate association and dissociation of PRCs, and are controlled by JDP2, might play an important role in the senescence program. The molecular

  6. Establishment of a novel fluorescence-based method to evaluate chaperone-mediated autophagy in a single neuron.

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    Takahiro Seki

    Full Text Available BACKGROUND: Chaperone-mediated autophagy (CMA is a selective autophagy-lysosome protein degradation pathway. The role of CMA in normal neuronal functions and in neural disease pathogenesis remains unclear, in part because there is no available method to monitor CMA activity at the single-cell level. METHODOLOGY/PRINCIPAL FINDINGS: We sought to establish a single-cell monitoring method by visualizing translocation of CMA substrates from the cytosol to lysosomes using the HaloTag (HT system. GAPDH, a CMA substrate, was fused to HT (GAPDH-HT; this protein accumulated in the lysosomes of HeLa cells and cultured cerebellar Purkinje cells (PCs after labeling with fluorescent dye-conjugated HT ligand. Lysosomal accumulation was enhanced by treatments that activate CMA and prevented by siRNA-mediated knockdown of LAMP2A, a lysosomal receptor for CMA, and by treatments that inactivate CMA. These results suggest that lysosomal accumulation of GAPDH-HT reflects CMA activity. Using this method, we revealed that mutant γPKC, which causes spinocerebellar ataxia type 14, decreased CMA activity in cultured PCs. CONCLUSION/SIGNIFICANCE: In the present study, we established a novel fluorescent-based method to evaluate CMA activity in a single neuron. This novel method should be useful and valuable for evaluating the role of CMA in various neuronal functions and neural disease pathogenesis.

  7. Arcabouço de PRP-gel associado a células tronco mesenquimais: uso em lesões condrais em modelo experimental equino

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    Ana Lúcia M. Yamada

    2016-06-01

    Full Text Available Resumo: O plasma rico em plaquetas (PRP é conhecido por apresentar propriedades anabólicas, anti-inflamatórias e capacidade de gelificação. Atualmente o PRP é considerado eficaz na reparação da cartilagem, sendo sua capacidade de formação de gel indicada para o preenchimento de defeitos condrais. O objetivo desse estudo foi analisar o uso do PRP ativado, no formato de arcabouço, como suporte para o implante de células tronco mesenquimais (CTM, no preenchimento e tratamento de lesões condrais induzidas em equinos. Doze equinos foram submetidos a uma cirurgia artroscópica no tempo zero do experimento (T0, onde foi induzida uma lesão condral de 15 mm de diâmetro na tróclea medial femoral dos membros pélvicos direito. As 12 articulações foram divididas em dois grupos distintos com seis articulações cada (GA e GB. As articulações do GA foram submetidas ao tratamento com o implante de CTM em gel de PRP. As articulações de GB foram o grupo controle do experimento. As CTMs foram extraídas do tecido adiposo e o PRP em gel foi obtido por protocolo de dupla centrifugação seguido da adição de trombina liofilizada. Após cinco meses (T150 foi realizada nova artroscopia para avaliação macroscópica do local, coleta de amostras do tecido de reparação para análises de microscopia eletrônica, sendo realizadas imagens ressonância magnética e tomografia computadorizada no local do implante no GA. Observamos que o gel de PRP associado às CTM demonstrou ser adequado no tratamento de defeitos condrais experimentais dos equinos. GA evidenciou um melhor aspecto macroscópico e microscópico do tecido de reparação, sendo que GB mostrou maior desorganização das fibras colágenas. Nas imagens de ressonância magnética e tomografia computadorizada apenas foi relevante o local da lesão condral. O arcabouço de gel de PRP demonstrou ser apropriado no suporte do tratamento com as CTMs, sendo de fácil aplicação e efetivo

  8. Changes in retinal venular oxygen saturation predict activity of proliferative diabetic retinopathy 3 months after panretinal photocoagulation

    DEFF Research Database (Denmark)

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin

    2018-01-01

    BACKGROUND/AIMS: Proliferative diabetic retinopathy (PDR) is a severe blinding condition. We investigated whether retinal metabolism, measured by retinal oximetry, may predict PDR activity after panretinal laser photocoagulation (PRP). METHODS: We performed a prospective, interventional, clinical...

  9. A Toxoplasma gondii Class XIV Myosin, Expressed in Sf9 Cells with a Parasite Co-chaperone, Requires Two Light Chains for Fast Motility*

    Science.gov (United States)

    Bookwalter, Carol S.; Kelsen, Anne; Leung, Jacqueline M.; Ward, Gary E.; Trybus, Kathleen M.

    2014-01-01

    Many diverse myosin classes can be expressed using the baculovirus/Sf9 insect cell expression system, whereas others have been recalcitrant. We hypothesized that most myosins utilize Sf9 cell chaperones, but others require an organism-specific co-chaperone. TgMyoA, a class XIVa myosin from the parasite Toxoplasma gondii, is required for the parasite to efficiently move and invade host cells. The T. gondii genome contains one UCS family myosin co-chaperone (TgUNC). TgMyoA expressed in Sf9 cells was soluble and functional only if the heavy and light chain(s) were co-expressed with TgUNC. The tetratricopeptide repeat domain of TgUNC was not essential to obtain functional myosin, implying that there are other mechanisms to recruit Hsp90. Purified TgMyoA heavy chain complexed with its regulatory light chain (TgMLC1) moved actin in a motility assay at a speed of ∼1.5 μm/s. When a putative essential light chain (TgELC1) was also bound, TgMyoA moved actin at more than twice that speed (∼3.4 μm/s). This result implies that two light chains bind to and stabilize the lever arm, the domain that amplifies small motions at the active site into the larger motions that propel actin at fast speeds. Our results show that the TgMyoA domain structure is more similar to other myosins than previously appreciated and provide a molecular explanation for how it moves actin at fast speeds. The ability to express milligram quantities of a class XIV myosin in a heterologous system paves the way for detailed structure-function analysis of TgMyoA and identification of small molecule inhibitors. PMID:25231988

  10. The MsPRP2 promoter enables strong heterologous gene expression in a root-specific manner and is enhanced by overexpression of Alfin 1.

    Science.gov (United States)

    Winicov, Ilga; Valliyodan, Babu; Xue, Lingru; Hoober, J Kenneth

    2004-10-01

    Promoter specificity and efficiency of utilization are essential for endogenous and transgene expression. Selective root expression remains to be defined in terms of both promoter elements and transcription factors that provide high levels of ubiquitous expression. We characterized expression from the MsPRP2 promoter with the green fluorescent protein (GFP) reporter transgene in alfalfa (Medicago sativa) and found that a promoter fragment (+1 to -652 bp) retained the root and callus specificity of the endogenous MsPRP2 gene and hence this promoter fragment contains elements necessary for root-specific expression. The strong ubiquitous expression obtained from this promoter was comparable to that of the CaMV 35S promoter in roots and was enhanced by transgenic overexpression of Alfin 1, a root- and callus-specific transcription factor in alfalfa. No transgenic expression was obtained in leaves with this promoter in the presence or absence of Alfin 1. The increased expression of GFP in alfalfa containing the Alfin 1 transgene confirms the function of Alfin 1 binding sites in the MsPRP2 promoter fragment and also indicates that Alfin 1 concentrations are limiting for maximal expression in calli and roots. These findings characterize the MsPRP2 promoter as a novel root- and callus-specific promoter of plant origin that can be used as an effective tool for strong root-directed gene expression. In addition, we have demonstrated that the signal sequence of MsPRP2 can be used for efficient secretion of transgene products from callus and roots.

  11. Dendritic cell-mediated-immunization with xenogenic PrP and adenoviral vectors breaks tolerance and prolongs mice survival against experimental scrapie.

    Directory of Open Access Journals (Sweden)

    Martine Bruley Rosset

    Full Text Available In prion diseases, PrP(c, a widely expressed protein, is transformed into a pathogenic form called PrP(Sc, which is in itself infectious. Antibodies directed against PrP(c have been shown to inhibit PrP(c to PrP(Sc conversion in vitro and protect in vivo from disease. Other effectors with potential to eliminate PrPSc-producing cells are cytotoxic T cells directed against PrP-derived peptides but their ability to protect or to induce deleterious autoimmune reactions is not known. The natural tolerance to PrP(c makes difficult to raise efficient adaptive responses. To break tolerance, adenovirus (Ad encoding human PrP (hPrP or control Ad were administered to wild-type mice by direct injection or by transfer of Ad-transduced dendritic cells (DCs. Control Ad-transduced DCs from Tg650 mice overexpressing hPrP were also used for immunization. DC-mediated but not direct administration of AdhPrP elicited antibodies that bound to murine native PrP(c. Frequencies of PrP-specific IFNgamma-secreting T cells were low and in vivo lytic activity only targeted cells strongly expressing hPrP. Immunohistochemical analysis revealed that CD3(+ T cell infiltration was similar in the brain of vaccinated and unvaccinated 139A-infected mice suggesting the absence of autoimmune reactions. Early splenic PrP(Sc replication was strongly inhibited ten weeks post infection and mean survival time prolonged from 209 days in untreated 139A-infected mice to 246 days in mice vaccinated with DCs expressing the hPrP. The efficacy appeared to be associated with antibody but not with cytotoxic cell-mediated PrP-specific responses.

  12. Platelet-rich plasma (PRP) and Platelet-Rich Fibrin (PRF): surgical adjuvants, preparations for in situ regenerative medicine and tools for tissue engineering.

    Science.gov (United States)

    Bielecki, Tomasz; Dohan Ehrenfest, David M

    2012-06-01

    The recent developement of platelet concentrate for surgical use is an evolution of the fibrin glue technologies used since many years. The initial concept of these autologous preparations was to concentrate platelets and their growth factors in a plasma solution, and to activate it into a fibrin gel on a surgical site, in order to improve local healing. These platelet suspensions were often called Platelet-Rich Plasma (PRP) like the platelet concentrate used in transfusion medicine, but many different technologies have in fact been developed; some of them are even no more platelet suspensions, but solid fibrin-based biomaterials called Platelet-Rich Fibrin (PRF). These various technologies were tested in many different clinical fields, particularly oral and maxillofacial surgery, Ear-Nose-Throat surgery, plastic surgery, orthopaedic surgery, sports medicine, gynecologic and cardiovascular surgery and ophthalmology. This field of research unfortunately suffers from the lack of a proper accurate terminology and the associated misunderstandings, and the literature on the topic is quite contradictory. Indeed, the effects of these preparations cannot be limited to their growth factor content: these products associate many actors of healing in synergy, such as leukocytes, fibrin matrix, and circulating progenitor cells, and are in fact as complex as blood itself. If platelet concentrates were first used as surgical adjuvants for the stimulation of healing (as fibrin glues enriched with growth factors), many applications for in situ regenerative medicine and tissue engineering were developed and offer a great potential. However, the future of this field is first dependent on his coherence and scientific clarity. The objectives of this article is to introduce the main definitions, problematics and perspectives that are described in this special issue of Current Pharmaceutical Biotechnology about platelet concentrates.

  13. Generation of human ER chaperone BiP in yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Čiplys, Evaldas; Aučynaitė, Agota; Slibinskas, Rimantas

    2014-02-11

    Human BiP is traditionally regarded as a major endoplasmic reticulum (ER) chaperone performing a number of well-described functions in the ER. In recent years it was well established that this molecule can also be located in other cell organelles and compartments, on the cell surface or be secreted. Also novel functions were assigned to this protein. Importantly, BiP protein appears to be involved in cancer and rheumatoid arthritis progression, autoimmune inflammation and tissue damage, and thus could potentially be used for therapeutic purposes. In addition, a growing body of evidence indicates BiP as a new therapeutic target for the treatment of neurodegenerative diseases. Increasing importance of this protein and its involvement in critical human diseases demands new source of high quality native recombinant human BiP for further studies and potential application. Here we introduce yeast Saccharomyces cerevisiae as a host for the generation of human BiP protein. Expression of a full-length human BiP precursor in S. cerevisiae resulted in a high-level secretion of mature recombinant protein into the culture medium. The newly discovered ability of the yeast cells to recognize, correctly process the native signal sequence of human BiP and secrete this protein into the growth media allowed simple one-step purification of highly pure recombinant BiP protein with yields reaching 10 mg/L. Data presented in this study shows that secreted recombinant human BiP possesses native amino acid sequence and structural integrity, is biologically active and without yeast-derived modifications. Strikingly, ATPase activity of yeast-derived human BiP protein exceeded the activity of E. coli-derived recombinant human BiP by a 3-fold. S. cerevisiae is able to correctly process and secrete human BiP protein. Consequently, resulting recombinant BiP protein corresponds accurately to native analogue. The ability to produce large quantities of native recombinant human BiP in yeast

  14. Stability of the Human Hsp90-p50Cdc37 Chaperone Complex against Nucleotides and Hsp90 Inhibitors, and the Influence of Phosphorylation by Casein Kinase 2

    Science.gov (United States)

    Olesen, Sanne H.; Ingles, Donna J.; Zhu, Jin-Yi; Martin, Mathew P.; Betzi, Stephane; Georg, Gunda I.; Tash, Joseph S.; Schönbrunn, Ernst

    2015-01-01

    The molecular chaperone Hsp90 is regulated by co-chaperones such as p50Cdc37, which recruits a wide selection of client protein kinases. Targeted disruption of the Hsp90-p50Cdc37 complex by protein-protein interaction (PPI) inhibitors has emerged as an alternative strategy to treat diseases characterized by aberrant Hsp90 activity. Using isothermal microcalorimetry, ELISA and GST-pull down assays we evaluated reported Hsp90 inhibitors and nucleotides for their ability to inhibit formation of the human Hsp90β-p50Cdc37 complex, reconstituted in-vitro from full-length proteins. Hsp90 inhibitors, including the proposed PPI inhibitors gedunin and H2-gamendazole, did not affect the interaction of Hsp90 with p50Cdc37 in vitro. Phosphorylation of Hsp90 and p50Cdc37 by casein kinase 2 (CK2) did not alter the thermodynamic signature of complex formation. However, the phosphorylated complex was vulnerable to disruption by ADP (IC50 = 32 µM), while ATP, AMPPNP and Hsp90 inhibitors remained largely ineffective. The differential inhibitory activity of ADP suggests that phosphorylation by CK2 primes the complex for dissociation in response to a drop in ATP/ADP levels. The approach applied herein provides robust assays for a comprehensive biochemical evaluation of potential effectors of the Hsp90-p50Cdc37 complex, such as phosphorylation by a kinase or the interaction with small molecule ligands. PMID:25608045

  15. Stability of the human Hsp90-p50Cdc37 chaperone complex against nucleotides and Hsp90 inhibitors, and the influence of phosphorylation by casein kinase 2.

    Science.gov (United States)

    Olesen, Sanne H; Ingles, Donna J; Zhu, Jin-Yi; Martin, Mathew P; Betzi, Stephane; Georg, Gunda I; Tash, Joseph S; Schönbrunn, Ernst

    2015-01-19

    The molecular chaperone Hsp90 is regulated by co-chaperones such as p50Cdc37, which recruits a wide selection of client protein kinases. Targeted disruption of the Hsp90-p50Cdc37 complex by protein-protein interaction (PPI) inhibitors has emerged as an alternative strategy to treat diseases characterized by aberrant Hsp90 activity. Using isothermal microcalorimetry, ELISA and GST-pull down assays we evaluated reported Hsp90 inhibitors and nucleotides for their ability to inhibit formation of the human Hsp90β-p50Cdc37 complex, reconstituted in vitro from full-length proteins. Hsp90 inhibitors, including the proposed PPI inhibitors gedunin and H2-gamendazole, did not affect the interaction of Hsp90 with p50Cdc37 in vitro. Phosphorylation of Hsp90 and p50Cdc37 by casein kinase 2 (CK2) did not alter the thermodynamic signature of complex formation. However, the phosphorylated complex was vulnerable to disruption by ADP (IC50 = 32 µM), while ATP, AMPPNP and Hsp90 inhibitors remained largely ineffective. The differential inhibitory activity of ADP suggests that phosphorylation by CK2 primes the complex for dissociation in response to a drop in ATP/ADP levels. The approach applied herein provides robust assays for a comprehensive biochemical evaluation of potential effectors of the Hsp90-p50Cdc37 complex, such as phosphorylation by a kinase or the interaction with small molecule ligands.

  16. Stability of the Human Hsp90-p50Cdc37 Chaperone Complex against Nucleotides and Hsp90 Inhibitors, and the Influence of Phosphorylation by Casein Kinase 2

    Directory of Open Access Journals (Sweden)

    Sanne H. Olesen

    2015-01-01

    Full Text Available The molecular chaperone Hsp90 is regulated by co-chaperones such as p50Cdc37, which recruits a wide selection of client protein kinases. Targeted disruption of the Hsp90-p50Cdc37 complex by protein–protein interaction (PPI inhibitors has emerged as an alternative strategy to treat diseases characterized by aberrant Hsp90 activity. Using isothermal microcalorimetry, ELISA and GST-pull down assays we evaluated reported Hsp90 inhibitors and nucleotides for their ability to inhibit formation of the human Hsp90β-p50Cdc37 complex, reconstituted in vitro from full-length proteins. Hsp90 inhibitors, including the proposed PPI inhibitors gedunin and H2-gamendazole, did not affect the interaction of Hsp90 with p50Cdc37 in vitro. Phosphorylation of Hsp90 and p50Cdc37 by casein kinase 2 (CK2 did not alter the thermodynamic signature of complex formation. However, the phosphorylated complex was vulnerable to disruption by ADP (IC50 = 32 µM, while ATP, AMPPNP and Hsp90 inhibitors remained largely ineffective. The differential inhibitory activity of ADP suggests that phosphorylation by CK2 primes the complex for dissociation in response to a drop in ATP/ADP levels. The approach applied herein provides robust assays for a comprehensive biochemical evaluation of potential effectors of the Hsp90-p50Cdc37 complex, such as phosphorylation by a kinase or the interaction with small molecule ligands.

  17. An unexpected role for the yeast nucleotide exchange factor Sil1 as a reductant acting on the molecular chaperone BiP.

    Science.gov (United States)

    Siegenthaler, Kevin D; Pareja, Kristeen A; Wang, Jie; Sevier, Carolyn S

    2017-03-03

    Unfavorable redox conditions in the endoplasmic reticulum (ER) can decrease the capacity for protein secretion, altering vital cell functions. While systems to manage reductive stress are well-established, how cells cope with an overly oxidizing ER remains largely undefined. In previous work (Wang et al., 2014), we demonstrated that the chaperone BiP is a sensor of overly oxidizing ER conditions. We showed that modification of a conserved BiP cysteine during stress beneficially alters BiP chaperone activity to cope with suboptimal folding conditions. How this cysteine is reduced to reestablish 'normal' BiP activity post-oxidative stress has remained unknown. Here we demonstrate that BiP's nucleotide exchange factor - Sil1 - can reverse BiP cysteine oxidation. This previously unexpected reductant capacity for yeast Sil1 has potential implications for the human ataxia Marinesco-Sjögren syndrome, where it is interesting to speculate that a disruption in ER redox-signaling (due to genetic defects in SIL1 ) may influence disease pathology.

  18. Chaperone-Assisted Formation of Cucurbit[8]uril-Based Molecular Porous Materials with One-Dimensional Channel Structure.

    Science.gov (United States)

    Zhu, Wei; Wang, Chen; Lan, Yue; Li, Jian; Wang, Hui; Gao, Ning; Ji, Jingwei; Li, Guangtao

    2016-09-06

    Exploiting "chaperone molecule" to navigate the successful assembly energy landscapes has been extensively used in biological systems, whereas in artifical supramolecular systems the "chaperone-assisted" assembly strategy to be used for the synthesis of materials with novel structures or the structures to be hardly prepared by "conventional" methods are still far from realizing the potential functions. In this work, we present a new example of small organic molecule acting as "chaperone molecule" in the facile formation of organic molecular porous materials. This porous material is composed of pure cucurbit[8]uril (CB[8]) macrocycle and possesses a honeycomb-like structure with an isolated and relatively large one-dimensional (1D) nanochannel. Moreover, it has good chemical and thermal stability, and shows a good adsorption capability for large molecule loading. Importantly, with the assistance of chaperone molecules, pure CB[8] could also be recycled even from a complex aqueous solution, demonstrating a powerful purification method of CB[8] from complex systems.

  19. MiR-17-5p impairs trafficking of H-ERG K+ channel protein by targeting multiple er stress-related chaperones during chronic oxidative stress.

    Directory of Open Access Journals (Sweden)

    Qi Wang

    Full Text Available BACKGROUND: To investigate if microRNAs (miRNAs play a role in regulating h-ERG trafficking in the setting of chronic oxidative stress as a common deleterious factor for many cardiac disorders. METHODS: We treated neonatal rat ventricular myocytes and HEK293 cells with stable expression of h-ERG with H2O2 for 12 h and 48 h. Expression of miR-17-5p seed miRNAs was quantified by real-time RT-PCR. Protein levels of chaperones and h-ERG trafficking were measured by Western blot analysis. Luciferase reporter gene assay was used to study miRNA and target interactions. Whole-cell patch-clamp techniques were employed to record h-ERG K(+ current. RESULTS: H-ERG trafficking was impaired by H2O2 after 48 h treatment, accompanied by reciprocal changes of expression between miR-17-5p seed miRNAs and several chaperones (Hsp70, Hsc70, CANX, and Golga2, with the former upregulated and the latter downregulated. We established these chaperones as targets for miR-17-5p. Application miR-17-5p inhibitor rescued H2O2-induced impairment of h-ERG trafficking. Upregulation of endogenous by H2O2 or forced miR-17-5p expression either reduced h-ERG current. Sequestration of AP1 by its decoy molecule eliminated the upregulation of miR-17-5p, and ameliorated impairment of h-ERG trafficking. CONCLUSIONS: Collectively, deregulation of the miR-17-5p seed family miRNAs can cause severe impairment of h-ERG trafficking through targeting multiple ER stress-related chaperones, and activation of AP1 likely accounts for the deleterious upregulation of these miRNAs, in the setting of prolonged duration of oxidative stress. These findings revealed the role of miRNAs in h-ERG trafficking, which may contribute to the cardiac electrical disturbances associated with oxidative stress.

  20. Review Article A Novel Regulatory Mechanism of Apoptosis by Calreticulin, a Molecular Chaperone in the Endoplasmic Reticulum

    OpenAIRE

    Ihara, Yoshito

    2003-01-01

    Calreticulin (CRT) is a Ca"--binding lectin-like molecular chaperone of the lumen of the endoplasmic reticulum. Recently, CRT has been revealed to be a multi-functional molecule related with glycoprotein maturation and chaperone function, Ca" homeostasis, cell adhesion, cell signaling, transcriptional regulation, and nuclear transporting mechanisms. CRT is also essential for cardiac and neural development in mice, suggesting an importance in the regulation of cell survival and death during de...

  1. The Role of System-Specific Molecular Chaperones in the Maturation of Molybdoenzymes in Bacteria

    Directory of Open Access Journals (Sweden)

    Meina Neumann

    2011-01-01

    Full Text Available Biogenesis of prokaryotic molybdoenzymes is a complex process with the final step representing the insertion of a matured molybdenum cofactor (Moco into a folded apoenzyme. Usually, specific chaperones of the XdhC family are required for the maturation of molybdoenzymes of the xanthine oxidase family in bacteria. Enzymes of the xanthine oxidase family are characterized to contain an equatorial sulfur ligand at the molybdenum center of Moco. This sulfur ligand is inserted into Moco while bound to the XdhC-like protein and before its insertion into the target enzyme. In addition, enzymes of the xanthine oxidase family bind either the molybdopterin (Mo-MPT form of Moco or the modified molybdopterin cytosine dinucleotide cofactor (MCD. In both cases, only the matured cofactor is inserted by a proofreading process of XdhC. The roles of these specific XdhC-like chaperones during the biogenesis of enzymes of the xanthine oxidase family in bacteria are described.

  2. The heat shock protein/chaperone network and multiple stress resistance

    KAUST Repository

    Jacob, Pierre

    2016-11-15

    Crop yield has been greatly enhanced during the last century. However, most elite cultivars are adapted to temperate climates and are not well suited to more stressful conditions. In the context of climate change, stress resistance is a major concern. To overcome these difficulties, scientists may help breeders by providing genetic markers associated with stress resistance. However, multi-stress resistance cannot be obtained from the simple addition of single stress resistance traits. In the field, stresses are unpredictable and several may occur at once. Consequently, the use of single stress resistance traits is often inadequate. Although it has been historically linked with the heat stress response, the heat shock protein (HSP)/chaperone network is a major component of multiple stress responses. Among the HSP/chaperone

  3. Amino acid sequence determinants and molecular chaperones in amyloid fibril formation.

    Science.gov (United States)

    Nerelius, Charlotte; Fitzen, Michael; Johansson, Jan

    2010-05-21

    Amyloid consists of cross-beta-sheet fibrils and is associated with about 25 human diseases, including several neurodegenerative diseases, systemic and localized amyloidoses and type II diabetes mellitus. Amyloid-forming proteins differ in structures and sequences, and it is to a large extent unknown what makes them convert from their native conformations into amyloid. In this review, current understanding of amino acid sequence determinants and the effects of molecular chaperones on amyloid formation are discussed. Studies of the nonpolar, transmembrane surfactant protein C (SP-C) have revealed amino acid sequence features that determine its amyloid fibril formation, features that are also found in the amyloid beta-peptide in Alzheimer's disease and the prion protein. Moreover, a proprotein chaperone domain (CTC(Brichos)) that prevents amyloid-like aggregation during proSP-C biosynthesis can prevent fibril formation also of other amyloidogenic proteins. 2010 Elsevier Inc. All rights reserved.

  4. Structure of Glycerol Dehydratase Reactivase: A New Type of Molecular Chaperone

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Der-Ing; Reiss, Lisa; Turner, Jr., Ivan; Dotson, Garry (Dupont)

    2010-03-08

    The function of glycerol dehydratase (GDH) reactivase is to remove damaged coenzyme B{sub 12} from GDH that has suffered mechanism-based inactivation. The structure of GDH reactivase from Klebsiella pneumoniae was determined at 2.4 {angstrom} resolution by the single isomorphous replacement with anomalous signal (SIR/AS) method. Each tetramer contains two elongated 63 kDa {alpha} subunits and two globular 14 kDa {beta} subunits. The {alpha} subunit contains structural features resembling both GroEL and Hsp70 groups of chaperones, and it appears chaperone like in its interactions with ATP. The fold of the {beta} subunit resembles that of the {beta} subunit of glycerol dehydratase, except that it lacks some coenzyme B12 binding elements. A hypothesis for the reactivation mechanism of reactivase is proposed based on these structural features.

  5. Transthyretin Amyloidosis: Chaperone Concentration Changes and Increased Proteolysis in the Pathway to Disease.

    Directory of Open Access Journals (Sweden)

    Gonçalo da Costa

    Full Text Available Transthyretin amyloidosis is a conformational pathology characterized by the extracellular formation of amyloid deposits and the progressive impairment of the peripheral nervous system. Point mutations in this tetrameric plasma protein decrease its stability and are linked to disease onset and progression. Since non-mutated transthyretin also forms amyloid in systemic senile amyloidosis and some mutation bearers are asymptomatic throughout their lives, non-genetic factors must also be involved in transthyretin amyloidosis. We discovered, using a differential proteomics approach, that extracellular chaperones such as fibrinogen, clusterin, haptoglobin, alpha-1-anti-trypsin and 2-macroglobulin are overrepresented in transthyretin amyloidosis. Our data shows that a complex network of extracellular chaperones are over represented in human plasma and we speculate that they act synergistically to cope with amyloid prone proteins. Proteostasis may thus be as important as point mutations in transthyretin amyloidosis.

  6. Metabolic and chaperone gene loss marks the origin of animals: evidence for Hsp104 and Hsp78 chaperones sharing mitochondrial enzymes as clients.

    Directory of Open Access Journals (Sweden)

    Albert J Erives

    Full Text Available The evolution of animals involved acquisition of an emergent gene repertoire for gastrulation. Whether loss of genes also co-evolved with this developmental reprogramming has not yet been addressed. Here, we identify twenty-four genetic functions that are retained in fungi and choanoflagellates but undetectable in animals. These lost genes encode: (i sixteen distinct biosynthetic functions; (ii the two ancestral eukaryotic ClpB disaggregases, Hsp78 and Hsp104, which function in the mitochondria and cytosol, respectively; and (iii six other assorted functions. We present computational and experimental data that are consistent with a joint function for the differentially localized ClpB disaggregases, and with the possibility of a shared client/chaperone relationship between the mitochondrial Fe/S homoaconitase encoded by the lost LYS4 gene and the two ClpBs. Our analyses lead to the hypothesis that the evolution of gastrulation-based multicellularity in animals led to efficient extraction of nutrients from dietary sources, loss of natural selection for maintenance of energetically expensive biosynthetic pathways, and subsequent loss of their attendant ClpB chaperones.

  7. Endoplasmic reticulum chaperone glucose regulated protein 170-Pokemon complexes elicit a robust antitumor immune response in vivo.

    Science.gov (United States)

    Yuan, Bangqing; Xian, Ronghua; Wu, Xianqu; Jing, Junjie; Chen, Kangning; Liu, Guojun; Zhou, Zhenhua

    2012-07-01

    Previous evidence suggested that the stress protein grp170 can function as a highly efficient molecular chaperone, binding to large protein substrates and acting as a potent vaccine against specific tumors when purified from the same tumor. In addition, Pokemon can be found in almost all malignant tumor cells and is regarded to be a promising candidate for the treatment of tumors. However, the potential of the grp170-Pokemon chaperone complex has not been well described. In the present study, the natural chaperone complex between grp170 and the Pokemon was formed by heat shock, and its immunogenicity was detected by ELISPOT and (51)Cr-release assays in vitro and by tumor bearing models in vivo. Our results demonstrated that the grp170-Pokemon chaperone complex could elicit T cell responses as determined by ELISPOT and (51)Cr-release assays. In addition, immunized C57BL/6 mice were challenged with subcutaneous (s.c.) injection of Lewis cancer cells to induce primary tumors. Treatment of mice with the grp170-Pokemon chaperone complex also significantly inhibited tumor growth and prolonged the life span of tumor-bearing mice. Our results indicated that the grp170-Pokemon chaperone complex might represent a powerful approach to tumor immunotherapy and have significant potential for clinical application. Copyright © 2012 Elsevier GmbH. All rights reserved.

  8. Mechanisms of Translocation of ER Chaperones to the Cell Surface and Immunomodulatory Roles in Cancer and Autoimmunity

    Science.gov (United States)

    Wiersma, Valerie R.; Michalak, Marek; Abdullah, Trefa M.; Bremer, Edwin; Eggleton, Paul

    2015-01-01

    Endoplasmic reticulum (ER) chaperones (e.g., calreticulin, heat shock proteins, and isomerases) perform a multitude of functions within the ER. However, many of these chaperones can translocate to the cytosol and eventually the surface of cells, particularly during ER stress induced by e.g., drugs, UV irradiation, and microbial stimuli. Once on the cell surface or in the extracellular space, the ER chaperones can take on immunogenic characteristics, as mostly described in the context of cancer, appearing as damage-associated molecular patterns recognized by the immune system. How ER chaperones relocate to the cell surface and interact with other intracellular proteins appears to influence whether a tumor cell is targeted for cell death. The relocation of ER proteins to the cell surface can be exploited to target cancer cells for elimination by immune mechanism. Here we evaluate the evidence for the different mechanisms of ER protein translocation and binding to the cell surface and how ER protein translocation can act as a signal for cancer cells to undergo killing by immunogenic cell death and other cell death pathways. The release of chaperones can also exacerbate underlying autoimmune conditions, such as rheumatoid arthritis and multiple sclerosis, and the immunomodulatory role of extracellular chaperones as potential cancer immunotherapies requires cautious monitoring, particularly in cancer patients with underlying autoimmune disease. PMID:25688334

  9. Mechanisms of translocation of ER chaperones to the cell surface and immunomodulatory roles in cancer and autoimmunity

    Directory of Open Access Journals (Sweden)

    Valerie R. Wiersma

    2015-01-01

    Full Text Available Endoplasmic reticulum (ER chaperones (e.g. calreticulin, heat shock proteins and isomerases perform a multitude of functions within the ER. However, many of these chaperones can translocate to the cytosol and eventually the surface of cells, particularly during ER stress induced by e.g. drugs, UV irradiation and microbial stimuli. Once on the cell surface or in the extracellular space, the ER chaperones can take on immunogenic characteristics, as mostly described in the context of cancer, appearing as damage-associated molecular patterns recognized by the immune system. How ER chaperones relocate to the cell surface and interact with other intracellular proteins appears to influence whether a tumor cell is targeted for cell death. The relocation of ER proteins to the cell surface can be exploited to target cancer cells for elimination by immune mechanism. Here we evaluate the evidence for the different mechanisms of ER protein translocation and binding to the cell surface and how ER protein translocation can act as a signal for cancer cells to undergo killing by immunogenic cell death and other cell death pathways. The release of chaperones can also exacerbate underlying autoimmune conditions, such as rheumatoid arthritis and multiple sclerosis, and the immunomodulatory role of extracellular chaperones as potential cancer immunotherapies requires cautious monitoring, particularly in cancer patients with underlying autoimmune disease.

  10. Mechanisms of Translocation of ER Chaperones to the Cell Surface and Immunomodulatory Roles in Cancer and Autoimmunity.

    Science.gov (United States)

    Wiersma, Valerie R; Michalak, Marek; Abdullah, Trefa M; Bremer, Edwin; Eggleton, Paul

    2015-01-01

    Endoplasmic reticulum (ER) chaperones (e.g., calreticulin, heat shock proteins, and isomerases) perform a multitude of functions within the ER. However, many of these chaperones can translocate to the cytosol and eventually the surface of cells, particularly during ER stress induced by e.g., drugs, UV irradiation, and microbial stimuli. Once on the cell surface or in the extracellular space, the ER chaperones can take on immunogenic characteristics, as mostly described in the context of cancer, appearing as damage-associated molecular patterns recognized by the immune system. How ER chaperones relocate to the cell surface and interact with other intracellular proteins appears to influence whether a tumor cell is targeted for cell death. The relocation of ER proteins to the cell surface can be exploited to target cancer cells for elimination by immune mechanism. Here we evaluate the evidence for the different mechanisms of ER protein translocation and binding to the cell surface and how ER protein translocation can act as a signal for cancer cells to undergo killing by immunogenic cell death and other cell death pathways. The release of chaperones can also exacerbate underlying autoimmune conditions, such as rheumatoid arthritis and multiple sclerosis, and the immunomodulatory role of extracellular chaperones as potential cancer immunotherapies requires cautious monitoring, particularly in cancer patients with underlying autoimmune disease.

  11. Enhanced Transport Capabilities via Nanotechnologies: Impacting Bioefficacy, Controlled Release Strategies, and Novel Chaperones

    Directory of Open Access Journals (Sweden)

    Thomai Panagiotou

    2011-01-01

    side affects and providing improved therapeutic interventions. Innovative nanotechnology applications, such as simultaneous targeting, imaging and delivery to tumors, are now possible through use of novel chaperones. Other examples include nanoparticles attachment to T-cells, release from novel hydrogel implants, and functionalized encapsulants. Difficult tasks such as drug delivery to the brain via the blood brain barrier and/or the cerebrospinal fluid are now easier to accomplish.

  12. Interactive Domains in the Molecular Chaperone Human ?B Crystallin Modulate Microtubule Assembly and Disassembly

    OpenAIRE

    Ghosh, Joy G.; Houck, Scott A.; Clark, John I.

    2007-01-01

    Small heat shock proteins regulate microtubule assembly during cell proliferation and in response to stress through interactions that are poorly understood.Novel functions for five interactive sequences in the small heat shock protein and molecular chaperone, human alphaB crystallin, were investigated in the assembly/disassembly of microtubules and aggregation of tubulin using synthetic peptides and mutants of human alphaB crystallin.The interactive sequence (113)FISREFHR(120) exposed on the ...

  13. Jasmonate signalling in Arabidopsis involves SGT1b-HSP70-HSP90 chaperone complexes.

    Science.gov (United States)

    Zhang, Xue-Cheng; Millet, Yves A; Cheng, Zhenyu; Bush, Jenifer; Ausubel, Frederick M

    Plant hormones play pivotal roles in growth, development and stress responses. Although it is essential to our understanding of hormone signalling, how plants maintain a steady state level of hormone receptors is poorly understood. We show that mutation of the Arabidopsis thaliana co-chaperone SGT1b impairs responses to the plant hormones jasmonate, auxin and gibberellic acid, but not brassinolide and abscisic acid, and that SGT1b and its homologue SGT1a are involved in maintaining the steady state levels of the F-box proteins COI1 and TIR1, receptors for jasmonate and auxin, respectively. The association of SGT1b with COI1 is direct and is independent of the Arabidopsis SKP1 protein, ASK1. We further show that COI1 is a client protein of SGT1b-HSP70-HSP90 chaperone complexes and that the complexes function in hormone signalling by stabilizing the COI1 protein. This study extends the SGT1b-HSP90 client protein list and broadens the functional scope of SGT1b-HSP70-HSP90 chaperone complexes.

  14. Heat Shock Proteins: A Review of the Molecular Chaperones for Plant Immunity

    Directory of Open Access Journals (Sweden)

    Chang-Jin Park

    2015-12-01

    Full Text Available As sessile organisms, plants are exposed to persistently changing stresses and have to be able to interpret and respond to them. The stresses, drought, salinity, chemicals, cold and hot temperatures, and various pathogen attacks have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. Heat shock proteins (HSPs functioning as molecular chaperones are the key components responsible for protein folding, assembly, translocation, and degradation under stress conditions and in many normal cellular processes. Plants respond to pathogen invasion using two different innate immune responses mediated by pattern recognition receptors (PRRs or resistance (R proteins. HSPs play an indispensable role as molecular chaperones in the quality control of plasma membrane-resident PRRs and intracellular R proteins against potential invaders. Here, we specifically discuss the functional involvement of cytosolic and endoplasmic reticulum (ER HSPs/chaperones in plant immunity to obtain an integrated understanding of the immune responses in plant cells.

  15. A review of acquired thermotolerance, heat shock proteins, and molecular chaperones in archaea

    Energy Technology Data Exchange (ETDEWEB)

    Trent, J.D.

    1996-05-01

    Acquired thermotolerance, the associated synthesis of heat-shock proteins (HSPs) under stress conditions, and the role of HSPs as molecular chaperones under normal growth conditions have been studied extensively in eukaryotes and bacteria, whereas research in these areas in archaea is only beginning. All organisms have evolved a variety of strategies for coping with high-temperature stress, and among these strategies is the increased synthesis of HSPs. The facts that both high temperatures and chemical stresses induce the HSPs and that some of the HSPs recognize and bind to unfolded proteins in vitro have led to the theory that the function of HSPs is to prevent protein aggregation in vivo. The facts that some HSPs are abundant under normal growth conditions and that they assist in protein folding in vitro have led to the theory that they assist protein folding in vivo; in this role, they are referred to as molecular chaperones. The limited research on acquired thermotolerance, HSPs, and molecular chaperones in archaea, particularly the hyperthermophilic archaea, suggests that these extremophiles provide a new perspective in these areas of research, both because they are members of a separate phylogenetic domain and because they have evolved to live under extreme conditions.

  16. The Clp Chaperones and Proteases of the Human Malaria Parasite Plasmodium falciparum

    Energy Technology Data Exchange (ETDEWEB)

    Bakkouri, Majida El; Pow, Andre; Mulichak, Anne; Cheung, Kevin L.Y.; Artz, Jennifer D.; Amani, Mehrnaz; Fell, Stuart; de Koning-Ward, Tania F.; Goodman, C. Dean; McFadden, Geoffrey I.; Ortega, Joaquin; Hui, Raymond; Houry, Walid A. (McMaster U.); (Melbourne); (Toronto); (Deakin); (HWMRI)

    2015-02-09

    The Clp chaperones and proteases play an important role in protein homeostasis in the cell. They are highly conserved across prokaryotes and found also in the mitochondria of eukaryotes and the chloroplasts of plants. They function mainly in the disaggregation, unfolding and degradation of native as well as misfolded proteins. Here, we provide a comprehensive analysis of the Clp chaperones and proteases in the human malaria parasite Plasmodium falciparum. The parasite contains four Clp ATPases, which we term PfClpB1, PfClpB2, PfClpC and PfClpM. One PfClpP, the proteolytic subunit, and one PfClpR, which is an inactive version of the protease, were also identified. Expression of all Clp chaperones and proteases was confirmed in blood-stage parasites. The proteins were localized to the apicoplast, a non-photosynthetic organelle that accommodates several important metabolic pathways in P. falciparum, with the exception of PfClpB2 (also known as Hsp101), which was found in the parasitophorous vacuole. Both PfClpP and PfClpR form mostly homoheptameric rings as observed by size-exclusion chromatography, analytical ultracentrifugation and electron microscopy. The X-ray structure of PfClpP showed the protein as a compacted tetradecamer similar to that observed for Streptococcus pneumoniae and Mycobacterium tuberculosis ClpPs. Our data suggest the presence of a ClpCRP complex in the apicoplast of P. falciparum.

  17. Antimicrobial activity of platelet-rich plasma and other plasma preparations against periodontal pathogens.

    Science.gov (United States)

    Yang, Li-Chiu; Hu, Suh-Woan; Yan, Min; Yang, Jaw-Ji; Tsou, Sing-Hua; Lin, Yuh-Yih

    2015-02-01

    In addition to releasing a pool of growth factors during activation, platelets have many features that indicate their role in the anti-infective host defense. The antimicrobial activities of platelet-rich plasma (PRP) and related plasma preparations against periodontal disease-associated bacteria were evaluated. Four distinct plasma fractions were extracted in the formulation used commonly in dentistry and were tested for their antibacterial properties against three periodontal bacteria: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum. The minimum inhibitory concentration of each plasma preparation was determined, and in vitro time-kill assays were used to detect their abilities to inhibit bacterial growth. Bacterial adhesion interference and the susceptibility of bacterial adherence by these plasma preparations were also conducted. All plasma preparations can inhibit bacterial growth, with PRP showing the superior activity. Bacterial growth inhibition by PRP occurred in the first 24 hours after application in the time-kill assay. PRP interfered with P. gingivalis and A. actinomycetemcomitans attachment and enhanced exfoliation of attached P. gingivalis but had no influences on F. nucleatum bacterial adherence. PRP expressed antibacterial properties, which may be attributed to platelets possessing additional antimicrobial molecules. The application of PRP on periodontal surgical sites is advisable because of its regenerative potential and its antibacterial effects.

  18. Protein arginine methyltransferase Prmt5-Mep50 methylates histones H2A and H4 and the histone chaperone nucleoplasmin in Xenopus laevis eggs.

    Science.gov (United States)

    Wilczek, Carola; Chitta, Raghu; Woo, Eileen; Shabanowitz, Jeffrey; Chait, Brian T; Hunt, Donald F; Shechter, David

    2011-12-09

    Histone proteins carry information contained in post-translational modifications. Eukaryotic cells utilize this histone code to regulate the usage of the underlying DNA. In the maturing oocytes and eggs of the frog Xenopus laevis, histones are synthesized in bulk in preparation for deposition during the rapid early developmental cell cycles. During this key developmental time frame, embryonic pluripotent chromatin is established. In the egg, non-chromatin-bound histones are complexed with storage chaperone proteins, including nucleoplasmin. Here we describe the identification and characterization of a complex of the protein arginine methyltransferase 5 (Prmt5) and the methylosome protein 50 (Mep50) isolated from Xenopus eggs that specifically methylates predeposition histones H2A/H2A.X-F and H4 and the histone chaperone nucleoplasmin on a conserved motif (GRGXK). We demonstrate that nucleoplasmin (Npm), an exceedingly abundant maternally deposited protein, is a potent substrate for Prmt5-Mep50 and is monomethylated and symmetrically dimethylated at Arg-187. Furthermore, Npm modulates Prmt5-Mep50 activity directed toward histones, consistent with a regulatory role for Npm in vivo. We show that H2A and nucleoplasmin methylation appears late in oogenesis and is most abundant in the laid egg. We hypothesize that these very abundant arginine methylations are constrained to pre-mid blastula transition events in the embryo and therefore may be involved in the global transcriptional repression found in this developmental time frame.

  19. Chaperone protein HYPK interacts with the first 17 amino acid region of Huntingtin and modulates mutant HTT-mediated aggregation and cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, Kamalika Roy [Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Centre for Neuroscience, Indian Institute of Science, Bangalore 560012 (India); Bhattacharyya, Nitai P., E-mail: nitai_sinp@yahoo.com [Biomedical Genomics Centre, PG Polyclinic Building, 5, Suburbun Hospital Road, Kolkata 700020 (India)

    2015-01-02

    Highlights: • HYPK reduces mutant HTT-mediated aggregate formation and cytotoxicity. • Interaction of HYPK with HTT requires N-terminal 17 amino acid of HTT (HTT-N17). • Deletion of HTT-N17 leads to SDS-soluble, smaller, nuclear aggregates. • These smaller aggregates do not associate with HYPK and are more cytotoxic. • Maybe, interaction of HYPK with amphipathic HTT-N17 block HTT aggregate formation. - Abstract: Huntington’s disease is a polyglutamine expansion disorder, characterized by mutant HTT-mediated aggregate formation and cytotoxicity. Many reports suggests roles of N-terminal 17 amino acid domain of HTT (HTT-N17) towards subcellular localization, aggregate formation and subsequent pathogenicity induced by N-terminal HTT harboring polyQ stretch in pathogenic range. HYPK is a HTT-interacting chaperone which can reduce N-terminal mutant HTT-mediated aggregate formation and cytotoxicity in neuronal cell lines. However, how HYPK interacts with N-terminal fragment of HTT remained unknown. Here we report that specific interaction of HYPK with HTT-N17 is crucial for the chaperone activity of HYPK. Deletion of HTT-N17 leads to formation of tinier, SDS-soluble nuclear aggregates formed by N-terminal mutant HTT. The increased cytotoxicity imparted by these tiny aggregates might be contributed due to loss of interaction with HYPK.

  20. Artemin, a diapause-specific chaperone, contributes to the stress tolerance of Artemia franciscana cysts and influences their release from females.

    Science.gov (United States)

    King, Allison M; Toxopeus, Jantina; MacRae, Thomas H

    2014-05-15

    Females of the crustacean Artemia franciscana produce either motile nauplii or gastrula stage embryos enclosed in a shell impermeable to nonvolatile compounds and known as cysts. The encysted embryos enter diapause, a state of greatly reduced metabolism and profound stress tolerance. Artemin, a diapause-specific ferritin homolog in cysts has molecular chaperone activity in vitro. Artemin represents 7.2% of soluble protein in cysts, approximately equal to the amount of p26, a small heat shock protein. However, there is almost twice as much artemin mRNA in cysts as compared with p26 mRNA, suggesting that artemin mRNA is translated less efficiently. RNA interference employing the injection of artemin double-stranded RNA into the egg sacs of A. franciscana females substantially reduced artemin mRNA and protein in cysts. Decreasing artemin diminished desiccation and freezing tolerance of cysts, demonstrating a role for this protein in stress resistance. Knockdown of artemin increased the time required for complete discharge of a brood of cysts carried within a female from a few hours up to 4 days, an effect weakened in successive broods. Artemin, an abundant molecular chaperone, contributes to stress tolerance of A. franciscana cysts while influencing their development and/or exit from females. © 2014. Published by The Company of Biologists Ltd.

  1. Sulforaphane Potentiates the Efficacy of 17-Allylamino 17-Demethoxygeldanamycin Against Pancreatic Cancer Through Enhanced Abrogation of Hsp90 Chaperone Function

    Science.gov (United States)

    Li, Yanyan; Zhang, Tao; Schwartz, Steven J.; Sun, Duxin

    2013-01-01

    Heat shock protein 90 (Hsp90), an essential molecular chaperone that regulates the stability of a wide range of oncogenic proteins, is a promising target for cancer therapeutics. We investigated the combination efficacy and potential mechanisms of sulforaphane, a dietary component from broccoli and broccoli sprouts, and 17-allylamino 17-demethoxygeldanamycin (17-AAG), an Hsp90 inhibitor, in pancreatic cancer. MTS assay demonstrated that sulforaphane sensitized pancreatic cancer cells to 17-AAG in vitro. Caspase-3 was activated to 6.4-fold in response to simultaneous treatment with sulforaphane and 17-AAG, whereas 17-AAG alone induced caspase-3 activity to 2-fold compared to control. ATP binding assay and coimmunoprecipitation revealed that sulforaphane disrupted Hsp90-p50Cdc37 interaction, whereas 17-AAG inhibited ATP binding to Hsp90. Concomitant use of sulforaphane and 17-AAG synergistically downregulated Hsp90 client proteins in Mia Paca-2 cells. Co-administration of sulforaphane and 17-AAG in pancreatic cancer xenograft model led to more than 70% inhibition of the tumor growth, whereas 17-AAG alone only suppressed the tumor growth by 50%. Our data suggest that sulforaphane potentiates the efficacy of 17-AAG against pancreatic cancer through enhanced abrogation of Hsp90 function. These findings provide a rationale for further evaluation of broccoli/broccoli sprout preparations combined with 17-AAG for better efficacy and lower dose-limiting toxicity in pancreatic cancer. PMID:21875325

  2. The Endoplasmic Reticulum Chaperone GRP78/BiP Modulates Prion Propagation in vitro and in vivo

    Science.gov (United States)

    Park, Kyung-Won; Eun Kim, Gyoung; Morales, Rodrigo; Moda, Fabio; Moreno-Gonzalez, Ines; Concha-Marambio, Luis; Lee, Amy S.; Hetz, Claudio; Soto, Claudio

    2017-01-01

    Prion diseases are fatal neurodegenerative disorders affecting several mammalian species, characterized by the accumulation of the misfolded form of the prion protein, which is followed by the induction of endoplasmic reticulum (ER) stress and the activation of the unfolded protein response (UPR). GRP78, also called BiP, is a master regulator of the UPR, reducing ER stress levels and apoptosis due to an enhancement of the cellular folding capacity. Here, we studied the role of GRP78 in prion diseases using several in vivo and in vitro approaches. Our results show that a reduction in the expression of this molecular chaperone accelerates prion pathogenesis in vivo. In addition, we observed that prion replication in cell culture was inversely related to the levels of expression of GRP78 and that both proteins interact in the cellular context. Finally, incubation of PrPSc with recombinant GRP78 led to the dose-dependent reduction of protease-resistant PrPSc in vitro. Our results uncover a novel role of GRP78 in reducing prion pathogenesis, suggesting that modulating its levels/activity may offer a novel opportunity for designing therapeutic approaches for these diseases. These findings may also have implications for other diseases involving the accumulation of misfolded proteins. PMID:28333162

  3. Discovery of a novel target for the dysglycemic chromogranin A fragment pancreastatin: interaction with the chaperone GRP78 to influence metabolism.

    Directory of Open Access Journals (Sweden)

    Nilima Biswas

    Full Text Available RATIONALE: The chromogranin A-derived peptide pancreastatin (PST is a dysglycemic, counter-regulatory peptide for insulin action, especially in liver. Although previous evidence for a PST binding protein has been reported, such a receptor has not been identified or sequenced. METHODS AND RESULTS: We used ligand affinity to purify the PST target, with biotinylated human PST (hCHGA273-301-amide as "bait" and mouse liver homogenate as "prey", and identified GRP78 (a.k.a. "78 kDa Glucose Regulated Protein", HSPA5, BIP as a major interacting partner of PST. GRP78 belongs to the family of heat shock proteins (chaperones, involved in several cellular processes including protein folding and glucose metabolism. We analyzed expression of GRP78 in the absence of PST in a mouse knockout model lacking its precursor CHGA: hepatic transcriptome data revealed global over-expression of not only GRP78 but also other heat shock transcripts (of the "adaptive UPR" in CHGA(-/- mice compared to wild-type (+/+. By contrast, we found a global decline in expression of hepatic pro-apoptotic transcripts in CHGA(-/- mice. GRP78's ATPase enzymatic activity was dose-dependently inhibited by PST (IC50∼5.2 µM. PST also inhibited the up-regulation of GRP78 expression during UPR activation (by tunicamycin in hepatocytes. PST inhibited insulin-stimulated glucose uptake in adipocytes, and increased hepatic expression of G6Pase (the final step in gluconeogenesis/glycogenolysis. In hepatocytes not only PST but also other GRP78-ATPase inhibitors (VER-155008 or ADP increased G6Pase expression. GRP78 over-expression inhibited G6Pase expression in hepatocytes, with partial restoration by GRP78-ATPase inhibitors PST, VER-155008, or ADP. CONCLUSIONS: Our results indicate that an unexpected major hepatic target of PST is the adaptive UPR chaperone GRP78. PST not only binds to GRP78 (in pH-dependent fashion, but also inhibits GRP78's ATPase enzymatic activity, and impairs its biosynthetic

  4. Crystallographic Studies of Prion Protein (PrP) Segments Suggest How Structural Changes Encoded by Polymorphism at Residue 129 Modulate Susceptibility to Human Prion Disease

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    Apostol, Marcin I.; Sawaya, Michael R.; Cascio, Duilio; Eisenberg, David (UCLA)

    2010-09-23

    A single nucleotide polymorphism (SNP) in codon 129 of the human prion gene, leading to a change from methionine to valine at residue 129 of prion protein (PrP), has been shown to be a determinant in the susceptibility to prion disease. However, the molecular basis of this effect remains unexplained. In the current study, we determined crystal structures of prion segments having either Met or Val at residue 129. These 6-residue segments of PrP centered on residue 129 are 'steric zippers,' pairs of interacting {beta}-sheets. Both structures of these 'homozygous steric zippers' reveal direct intermolecular interactions between Met or Val in one sheet and the identical residue in the mating sheet. These two structures, plus a structure-based model of the heterozygous Met-Val steric zipper, suggest an explanation for the previously observed effects of this locus on prion disease susceptibility and progression.

  5. Immunohistochemistry for PrPSc in natural scrapie reveals patterns which are associated with the PrP genotype.

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    Spiropoulos, J; Casalone, C; Caramelli, M; Simmons, M M

    2007-08-01

    Immunohistochemistry for PrPSc is used widely in scrapie diagnosis. In natural scrapie cases the use of immunohistochemistry (IHC) has revealed the existence of up to 12 different morphological types of immunostained deposits. The significance of this pattern variability in relation to genotype has not been studied extensively in natural disease. In this study we recorded in detail PrPSc patterns at the obex level of the medulla oblongata from 163 animals derived from 55 flocks which presented through passive surveillance in the UK and Italy. A strong association was seen between PrPSc patterns and PrP genotype, particularly in relation to codon 136. In a blind assessment of this association we were able to predict, with over 80% accuracy, the genotype of 151 scrapie cases which were presented through passive surveillance from 13 farms. The genotype of these cases was ARQ/ARQ or VRQ/VRQ. The association of PrPsc patterns with genotype was generally stronger in those farms where all the affected animals belonged to a single genotype compared with farms where both genotypes were identified, with the exception of one farm in which the genotype of all affected sheep was ARQ/ARQ and the PrPSc patterns were of the VRQ/VRQ type. Our observations support the hypothesis that the observed association between specific IHC patterns and genotypes may in fact be strain driven but in natural disease individual scrapie strains may demonstrate a genotypic tropism.

  6. Peroxiredoxin 6 promotes upregulation of the prion protein (PrP in neuronal cells of prion-infected mice

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    Wagner Wibke

    2012-12-01

    Full Text Available Abstract Background It has been widely established that the conversion of the cellular prion protein (PrPC into its abnormal isoform (PrPSc is responsible for the development of transmissible spongiform encephalopathies (TSEs. However, the knowledge of the detailed molecular mechanisms and direct functional consequences within the cell is rare. In this study, we aimed at the identification of deregulated proteins which might be involved in prion pathogenesis. Findings Apolipoprotein E and peroxiredoxin 6 (PRDX6 were identified as upregulated proteins in brains of scrapie-infected mice and cultured neuronal cell lines. Downregulation of PrP gene expression using specific siRNA did not result in a decrease of PRDX6 amounts. Interestingly, selective siRNA targeting PRDX6 or overexpression of PRDX6 controlled PrPC and PrPSc protein amounts in neuronal cells. Conclusions Besides its possible function as a novel marker protein in the diagnosis of TSEs, PDRX6 represents an attractive target molecule in putative pharmacological intervention strategies in the future.

  7. Immediately loaded dental implants bioactivated with platelet-rich plasma (PRP) placed in maxillary and mandibular region.

    Science.gov (United States)

    Inchingolo, F; Ballini, A; Cagiano, R; Inchingolo, A D; Serafini, M; De Benedittis, M; Cortelazzi, R; Tatullo, M; Marrelli, M; Inchingolo, A M; Vermesan, D; Del Corso, M; Malcangi, G; Diteodoro, S; Mura, S A; Cantore, S; Cortelazzi, A; Paduanelli, G; Resta, G; Muollo, F; Cirulli, N; Pettini, F; Farronato, D; De Vito, D; Caprio, M; Haragus, H; Dipalma, G

    2015-01-01

    Dental implants have today deeply changed the dental field. In fact, after almost 50 years, the permanent placement of a titanium screw with an attached tooth have, step by step, changed the society's standard toward a permanently replacement of missed or severely damaged teeth. In fact, the host of benefits born from dental implants have affected both patients and dental professionals. The aim of the present study is to report the outcomes of an implant therapy protocol supporting fixed prostheses implanted soon after extractions and loaded with flapless guided surgery by a 3D software planning. 37 patients, requiring rehabilitation of booth dental arches with a one-to-one technique, were enrolled in a follow-up study plan which established clinical and radiological examinations on the day after surgery, seven months and one year later. Platelet Rich Plasma (PRP), in combination with autogenous bone, organic bone material and organic bone substitutes, was used before implant-prosthetic rehabilitation with an its prompt loading just before the implant insertion phase. Definitive restorations were delivered at 6-12 months after surgical procedure. One year after loading there were no dropouts and no failure of the definitive prosthesis. Furthermore, the feedback from patients resulted positive. Patients resulted satisfied both aesthetically and functionally regarding these types of prosthetic reconstructions made at the time.

  8. Bcl-2 regulates HIF-1alpha protein stabilization in hypoxic melanoma cells via the molecular chaperone HSP90.

    Directory of Open Access Journals (Sweden)

    Daniela Trisciuoglio

    activation of HIF-1 in hypoxic tumour cells involving the beta isoform of molecular chaperone HSP90.

  9. Optimization of overexpression of a chaperone protein of steroid C25 dehydrogenase for biochemical and biophysical characterization.

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    Niedzialkowska, Ewa; Mrugała, Beata; Rugor, Agnieszka; Czub, Mateusz P; Skotnicka, Anna; Cotelesage, Julien J H; George, Graham N; Szaleniec, Maciej; Minor, Wladek; Lewiński, Krzysztof

    2017-06-01

    Molybdenum is an essential nutrient for metabolism in plant, bacteria, and animals. Molybdoenzymes are involved in nitrogen assimilation and oxidoreductive detoxification, and bioconversion reactions of environmental, industrial, and pharmaceutical interest. Molybdoenzymes contain a molybdenum cofactor (Moco), which is a pyranopterin heterocyclic compound that binds a molybdenum atom via a dithiolene group. Because Moco is a large and complex compound deeply buried within the protein, molybdoenzymes are accompanied by private chaperone proteins responsible for the cofactor's insertion into the enzyme and the enzyme's maturation. An efficient recombinant expression and purification of both Moco-free and Moco-containing molybdoenzymes and their chaperones is of paramount importance for fundamental and applied research related to molybdoenzymes. In this work, we focused on a D1 protein annotated as a chaperone of steroid C25 dehydrogenase (S25DH) from Sterolibacterium denitrificans Chol-1S. The D1 protein is presumably involved in the maturation of S25DH engaged in oxygen-independent oxidation of sterols. As this chaperone is thought to be a crucial element that ensures the insertion of Moco into the enzyme and consequently, proper folding of S25DH optimization of the chaperon's expression is the first step toward the development of recombinant expression and purification methods for S25DH. We have identified common E. coli strains and conditions for both expression and purification that allow us to selectively produce Moco-containing and Moco-free chaperones. We have also characterized the Moco-containing chaperone by EXAFS and HPLC analysis and identified conditions that stabilize both forms of the protein. The protocols presented here are efficient and result in protein quantities sufficient for biochemical studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. The AGAAAAGA palindrome in PrP is required to generate a productive PrPSc-PrPC complex that leads to prion propagation.

    Science.gov (United States)

    Norstrom, Eric M; Mastrianni, James A

    2005-07-22

    The molecular hallmark of prion disease is the conversion of normal prion protein (PrPC) to an insoluble, proteinase K-resistant, pathogenic isoform (PrPSc). Once generated, PrPSc propagates by complexing with, and transferring its pathogenic conformation onto, PrPC. Defining the specific nature of this PrPSc-PrPC interaction is critical to understanding prion genesis. To begin to approach this question, we employed a prion-infected neuroblastoma cell line (ScN2a) combined with a heterologous yeast expression system to independently model PrPSc generation and propagation. We additionally applied fluorescence resonance energy transfer analysis to the latter to specifically study PrP-PrP interactions. In this report we focus on an N-terminal hydrophobic palindrome of PrP (112-AGAAAAGA-119) thought to feature intimately in prion generation via an unclear mechanism. We found that, in contrast to wild type (wt) PrP, PrP lacking the palindrome (PrPDelta112-119) neither converted to PrPSc when expressed in ScN2a cells nor generated proteinase K-resistant PrP when expressed in yeast. Furthermore, PrPDelta112-119 was a dominant-negative inhibitor of wtPrP in ScN2a cells. Both wtPrP and PrPDelta112-119 were highly insoluble when expressed in yeast and produced distinct cytosolic aggregates when expressed as fluorescent fusion proteins (PrP::YFP). Although self-aggregation was evident, fluorescence resonance energy transfer studies in live yeast co-expressing PrPSc-like protein and PrPDelta112-119 indicated altered interaction properties. These results suggest that the palindrome is required, not only for the attainment of the PrPSc conformation but also to facilitate the proper association of PrPSc with PrPC to effect prion propagation.

  11. THE EFFECT OF ORGANIC FERTILISATION OF LIQUID MANURE AND THE PRP FIX PREPARATION ON THE YIELD AND CHEMICAL COMPOSITION OF WINTER RAPE SEEDS AND SPRING WHEAT GRAIN

    Directory of Open Access Journals (Sweden)

    Ewa Możdżer

    2017-01-01

    Full Text Available In 2011–2013, a field experiment was carried out at the Experimental Station of Cultivar Evaluation in Szczecin-Dąbie. The experiment aimed at determining the effect of slurry without and with addition of increasing PRP Fix preparation doses on the crop yields and some of their qualitative traits. The soil where the experiment was set up was slightly acidic (pHKCL 5.95; nitrogen, phosphorus and potassium contents were 0.86, 1.55 and 2.70 g·kg-1 d.m., respectively. The total content of macro-elements for this type of soil was average. The content of bioavailable forms of phosphorus, magnesium and sulphur was average, while that of potassium was high. The content of organic carbon in soil was low, while the C:N ratio was 10.2:1 and was average for that type of soils. The obtained results show that the applied fertilisation with slurry combined with PRP Fix preparation and PK fertilisation increased the yield of winter rape seeds and spring wheat grain and the content of macro-elements being examined in them. The yields of the test plants were larger in the fertilisation objects where fertilisation with slurry with addition of 8 kg PRP Fix preparation pe