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Sample records for abc transporter involved

  1. Insight into Two ABC Transporter Families Involved in Lantibiotic Resistance

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    Rebecca Clemens

    2018-01-01

    Full Text Available Antimicrobial peptides, which contain (methyl-lanthionine-rings are called lantibiotics. They are produced by several Gram-positive bacteria and are mainly active against these bacteria. Although these are highly potent antimicrobials, some human pathogenic bacteria express specific ABC transporters that confer resistance and counteract their antimicrobial activity. Two distinct ABC transporter families are known to be involved in this process. These are the Cpr- and Bce-type ABC transporter families, named after their involvement in cationic peptide resistance in Clostridium difficile, and bacitracin efflux in Bacillus subtilis, respectively. Both resistance systems differentiate to each other in terms of the proteins involved. Here, we summarize the current knowledge and describe the divergence as well as the common features present in both the systems to confer lantibiotic resistance.

  2. ABC and MFS transporters from Botrytis cinerea involved in sensitivity to fungicides and natural toxic compounds

    NARCIS (Netherlands)

    Hayashi, K.

    2003-01-01

    ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporters are two major classes of proteins involved in drug resistance. ABC transporter proteins are primary transporters that use the energy generated by ATP hydrolysis to transport drugs over membranes, while MFS transport

  3. ABC transporters from Aspergillus nidulans are involved in protection against cytotoxic agents and antibiotic production

    NARCIS (Netherlands)

    Andrade, A.C.; Nistelrooy, van J.G.M.; Peery, R.B.; Skatrud, P.L.; Waard, de M.A.

    2000-01-01

    This paper describes the characterization of atrC and atrD (ABC transporters C and D), two novel ABC transporter-encoding genes from the filamentous fungus Aspergillus nidulans, and provides evidence for the involvement of atrD in multidrug transport and antibiotic production. BLAST analysis of the

  4. Plant ABC Transporters

    Science.gov (United States)

    Kang, Joohyun; Park, Jiyoung; Choi, Hyunju; Burla, Bo; Kretzschmar, Tobias; Lee, Youngsook; Martinoia, Enrico

    2011-01-01

    ABC transporters constitute one of the largest protein families found in all living organisms. ABC transporters are driven by ATP hydrolysis and can act as exporters as well as importers. The plant genome encodes for more than 100 ABC transporters, largely exceeding that of other organisms. In Arabidopsis, only 22 out of 130 have been functionally analyzed. They are localized in most membranes of a plant cell such as the plasma membrane, the tonoplast, chloroplasts, mitochondria and peroxisomes and fulfill a multitude of functions. Originally identified as transporters involved in detoxification processes, they have later been shown to be required for organ growth, plant nutrition, plant development, response to abiotic stresses, pathogen resistance and the interaction of the plant with its environment. To fulfill these roles they exhibit different substrate specifies by e.g. depositing surface lipids, accumulating phytate in seeds, and transporting the phytohormones auxin and abscisic acid. The aim of this review is to give an insight into the functions of plant ABC transporters and to show their importance for plant development and survival. PMID:22303277

  5. Thermodynamics of ABC transporters

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    Xuejun C. Zhang

    2015-09-01

    Full Text Available ABSTRACT ABC transporters form the largest of all transporter families, and their structural study has made tremendous progress over recent years. However, despite such advances, the precise mechanisms that determine the energy-coupling between ATP hydrolysis and the conformational changes following substrate binding remain to be elucidated. Here, we present our thermodynamic analysis for both ABC importers and exporters, and introduce the two new concepts of differential-binding energy and elastic conformational energy into the discussion. We hope that the structural analysis of ABC transporters will henceforth take thermodynamic aspects of transport mechanisms into account as well.

  6. A putative ABC transporter is involved in negative regulation of biofilm formation by Listeria monocytogenes

    DEFF Research Database (Denmark)

    Zhu, Xinna; Long, Fei; Chen, Yonghui

    2008-01-01

    with enhanced ability of biofilm-formation generated via transposon Tn917 mutagenesis of L. monocytogenes 4b G. In this mutant, a Tn917 insertion has disrupted the coding region of the gene encoding a putative ATP binding cassette (ABC) transporter permease identical to Lmof2365_1771 (a putative ABC...... regulation of biofilm formation by L. monocytogenes 4b G. The immediate gene upstream of lm.G_1771 encoded an ATP-binding protein. Bioinformatics analysis suggested that these two genes were organized into an operon and that their proteins formed an export ABC transporter. Here, we report...... the characterization of the mutant and identification of a novel ABC transporter that functions in negative regulation of biofilm formation in L. monocytogenes....

  7. Mercury toxicokinetics of the healthy human term placenta involve amino acid transporters and ABC transporters

    International Nuclear Information System (INIS)

    Straka, Elisabeth; Ellinger, Isabella; Balthasar, Christina; Scheinast, Matthias; Schatz, Jasmin; Szattler, Tamara; Bleichert, Sonja; Saleh, Leila; Knöfler, Martin; Zeisler, Harald; Hengstschläger, Markus; Rosner, Margit; Salzer, Hans; Gundacker, Claudia

    2016-01-01

    Highlights: • It is known that MeHg is able to pass the placenta and to affect fetal brain development. • Uptake and efflux transporters were examined in human primary trophoblast cells and BeWo cells. • Involvement in mercury transfer was assessed by measurement of cellular mercury content upon siRNA mediated gene knockdown. • Localization of transporters was determined by immunofluorescence microscopy. • LAT1 and rBAT at the apical membrane of the syncytiotrophoblast (STB) are involved in MeHg uptake. • MRP1 located at basal membrane of STB mediates mercury efflux. - Abstract: Background: The capacity of the human placenta to handle exogenous stressors is poorly understood. The heavy metal mercury is well-known to pass the placenta and to affect brain development. An active transport across the placenta has been assumed. The underlying mechanisms however are virtually unknown. Objectives: Uptake and efflux transporters (17 candidate proteins) assumed to play a key role in placental mercury transfer were examined for expression, localization and function in human primary trophoblast cells and the trophoblast-derived choriocarcinoma cell line BeWo. Methods: To prove involvement of the transporters, we used small interfering RNA (siRNA) and exposed cells to methylmercury (MeHg). Total mercury contents of cells were analyzed by Cold vapor-atomic fluorescence spectrometry (CV-AFS). Localization of the proteins in human term placenta sections was determined via immunofluorescence microscopy. Results: We found the amino acid transporter subunits L-type amino acid transporter (LAT)1 and rBAT (related to b 0,+ type amino acid transporter) as well as the efflux transporter multidrug resistance associated protein (MRP)1 to be involved in mercury kinetics of trophoblast cells (t-test P < 0.05). Conclusion: The amino acid transporters located at the apical side of the syncytiotrophoblast (STB) manage uptake of MeHg. Mercury conjugated to glutathione (GSH) is

  8. ABCdb: an ABC transporter database.

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    Quentin, Y; Fichant, G

    2000-10-01

    We present the first release of a database devoted to the ATP-binding cassette (ABC) protein domains (ABCdb). The ABC proteins are involved in a wide variety of physiological processes in Archea, Bacteria and Eucaryota where they are encoded by large families of paralogous genes. The majority of ABC domains energize the transport of compounds across the membranes. In bacteria, ABC transporters are involved in the uptake of a wide range of molecules and in mechanisms of virulence and antibiotic resistance. In eukaryotes, most of them are involved in drug resistance and in human cells, many are associated with diseases. Sequence analysis reveals that members of the ABC superfamily can be organized into sub-families and suggests that they have diverged from common ancestral forms. In this release, ABCdb includes the inventory and assembly of the ABC transporter systems of completely sequenced genomes. In addition to the protein entries, the database comprises information on functional domains, sequence motifs, predicted trans-membrane segments, and signal peptides. It also includes a classification in sub-families of the ABC systems as well as a classification of the different partners of the systems. Evolutionary trees and specific sequence patterns are provided for each sub-family. The database is endowed with a powerful query system and it was interfaced with blastP2 program for similarity searches. ABCdb has been developed in the ACeDB format, a database system developed by Jean Thierry-Mieg and Richard Durbin. ABCdb can be accessed via the World Wide Web (http://ir2lcb.cnrs-mrs.fr/ABCdb/).

  9. Structural diversity of ABC transporters

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    ter Beek, Josy; Guskov, Albert

    2014-01-01

    ATP-binding cassette (ABC) transporters form a large superfamily of ATP-dependent protein complexes that mediate transport of a vast array of substrates across membranes. The 14 currently available structures of ABC transporters have greatly advanced insight into the transport mechanism and revealed a tremendous structural diversity. Whereas the domains that hydrolyze ATP are structurally related in all ABC transporters, the membrane-embedded domains, where the substrates are translocated, adopt four different unrelated folds. Here, we review the structural characteristics of ABC transporters and discuss the implications of this structural diversity for mechanistic diversity. PMID:24638992

  10. Yeast ABC proteins involved in multidrug resistance.

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    Piecuch, Agata; Obłąk, Ewa

    2014-03-01

    Pleiotropic drug resistance is a complex phenomenon that involves many proteins that together create a network. One of the common mechanisms of multidrug resistance in eukaryotic cells is the active efflux of a broad range of xenobiotics through ATP-binding cassette (ABC) transporters. Saccharomyces cerevisiae is often used as a model to study such activity because of the functional and structural similarities of its ABC transporters to mammalian ones. Numerous ABC transporters are found in humans and some are associated with the resistance of tumors to chemotherapeutics. Efflux pump modulators that change the activity of ABC proteins are the most promising candidate drugs to overcome such resistance. These modulators can be chemically synthesized or isolated from natural sources (e.g., plant alkaloids) and might also be used in the treatment of fungal infections. There are several generations of synthetic modulators that differ in specificity, toxicity and effectiveness, and are often used for other clinical effects.

  11. The ABC transporters in Candidatus Liberibacter asiaticus

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    Li, Wenlin; Cong, Qian; Pei, Jimin; Kinch, Lisa N; Grishin, Nick V

    2012-01-01

    Candidatus Liberibacter asiaticus (Ca. L. asiaticus) is a Gram-negative bacterium and the pathogen of Citrus Greening disease (Huanglongbing, HLB). As a parasitic bacterium, Ca. L. asiaticus harbors ABC transporters that play important roles in exchanging chemical compounds between Ca. L. asiaticus and its host. Here, we analyzed all the ABC transporter-related proteins in Ca. L. asiaticus. We identified 14 ABC transporter systems and predicted their structures and substrate specificities. In-depth sequence and structure analysis including multiple sequence alignment, phylogenetic tree reconstruction, and structure comparison further support their function predictions. Our study shows that this bacterium could use these ABC transporters to import metabolites (amino acids and phosphates) and enzyme cofactors (choline, thiamine, iron, manganese, and zinc), resist to organic solvent, heavy metal, and lipid-like drugs, maintain the composition of the outer membrane (OM), and secrete virulence factors. Although the features of most ABC systems could be deduced from the abundant experimental data on their orthologs, we reported several novel observations within ABC system proteins. Moreover, we identified seven nontransport ABC systems that are likely involved in virulence gene expression regulation, transposon excision regulation, and DNA repair. Our analysis reveals several candidates for further studies to understand and control the disease, including the type I virulence factor secretion system and its substrate that are likely related to Ca. L. asiaticus pathogenicity and the ABC transporter systems responsible for bacterial OM biosynthesis that are good drug targets. PMID:22807026

  12. ABC transporters : Lessons from a bacterial oligopeptide uptake system

    NARCIS (Netherlands)

    Doeven, Mark Koop

    2006-01-01

    ABC transporters are proteins that are involved in the uptake of nutrients and excretion of harmful substances in biological cells. Defects in human ABC transporters can result in severe diseases. Too high ABC transporter activity can lead to non-responsiveness of cancercells to chemotherapy, and

  13. ABC transporters in adaptive immunity.

    Science.gov (United States)

    Seyffer, Fabian; Tampé, Robert

    2015-03-01

    ABC transporters ubiquitously found in all kingdoms of life move a broad range of solutes across membranes. Crystal structures of four distinct types of ABC transport systems have been solved, shedding light on different conformational states within the transport process. Briefly, ATP-dependent flipping between inward- and outward-facing conformations allows directional transport of various solutes. The heterodimeric transporter associated with antigen processing TAP1/2 (ABCB2/3) is a crucial element of the adaptive immune system. The ABC transport complex shuttles proteasomal degradation products into the endoplasmic reticulum. These antigenic peptides are loaded onto major histocompatibility complex class I molecules and presented on the cell surface. We detail the functional modules of TAP, its ATPase and transport cycle, and its interaction with and modulation by other cellular components. In particular, we emphasize how viral factors inhibit TAP activity and thereby prevent detection of the infected host cell by cytotoxic T-cells. Merging functional details on TAP with structural insights from related ABC transporters refines the understanding of solute transport. Although human ABC transporters are extremely diverse, they still may employ conceptually related transport mechanisms. Appropriately, we delineate a working model of the transport cycle and how viral factors arrest TAP in distinct conformations. Deciphering the transport cycle of human ABC proteins is the major issue in the field. The defined peptidic substrate, various inhibitory viral factors, and its role in adaptive immunity provide unique tools for the investigation of TAP, making it an ideal model system for ABC transporters in general. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Yeast ABC transporters in lipid trafficking.

    Science.gov (United States)

    Prasad, Rajendra; Khandelwal, Nitesh Kumar; Banerjee, Atanu

    2016-08-01

    Throughout its evolution, the ATP-binding cassette (ABC) transporter superfamily has experienced a rapid expansion in its substrate repertoire and functions. Of the diverse functions that these pumps offer, their drug transport properties have attracted considerable attention primarily owing to their clinical significance. Despite this fact, emerging evidence suggests that physiological substrates of transporters also affect the overall functioning of an organism. Lipids, as substrates of ABC transporters, constitute one feature found in all representative groups of the living kingdom. Due to the importance of lipid species in the cellular physiology of an organism, their proper distribution within cells is crucial. This fact is well exemplified by the vast number of medical conditions that have been caused as a result of perturbations in ABC transporter-mediated lipid transport in higher organisms. In yeasts, apart from providing transport functions, ABC transporters also coordinate regulatory networks with lipids. This review focuses on yeast ABC transporters involved in the transport of lipids and briefly discusses the integration of their regulatory network with that of the lipid species. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Phylogenetic analysis of fungal ABC transporters

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    Driessen Arnold JM

    2010-03-01

    Full Text Available Abstract Background The superfamily of ABC proteins is among the largest known in nature. Its members are mainly, but not exclusively, involved in the transport of a broad range of substrates across biological membranes. Many contribute to multidrug resistance in microbial pathogens and cancer cells. The diversity of ABC proteins in fungi is comparable with those in multicellular animals, but so far fungal ABC proteins have barely been studied. Results We performed a phylogenetic analysis of the ABC proteins extracted from the genomes of 27 fungal species from 18 orders representing 5 fungal phyla thereby covering the most important groups. Our analysis demonstrated that some of the subfamilies of ABC proteins remained highly conserved in fungi, while others have undergone a remarkable group-specific diversification. Members of the various fungal phyla also differed significantly in the number of ABC proteins found in their genomes, which is especially reduced in the yeast S. cerevisiae and S. pombe. Conclusions Data obtained during our analysis should contribute to a better understanding of the diversity of the fungal ABC proteins and provide important clues about their possible biological functions.

  16. Phylogenetic analysis of fungal ABC transporters

    NARCIS (Netherlands)

    Kovalchuk, Andriy; Driessen, Arnold J. M.

    2010-01-01

    Background: The superfamily of ABC proteins is among the largest known in nature. Its members are mainly, but not exclusively, involved in the transport of a broad range of substrates across biological membranes. Many contribute to multidrug resistance in microbial pathogens and cancer cells. The

  17. The peroxisomal ABC transporter family

    NARCIS (Netherlands)

    Wanders, Ronald J. A.; Visser, Wouter F.; van Roermund, Carlo W. T.; Kemp, Stephan; Waterham, Hans R.

    2007-01-01

    This review describes the current state of knowledge about the ABCD family of peroxisomal half adenosine-triphosphate-binding cassette (ABC) transporters. ABCDs are predicted to be present in a variety of eukaryotic organisms, although at present, only ABCDs in the yeast Saccharomyces cerevisiae,

  18. Involvement of the carboxyl-terminal region of the yeast peroxisomal half ABC transporter Pxa2p in its interaction with Pxa1p and in transporter function.

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    Cheng-Yi Chuang

    Full Text Available The peroxisome is a single membrane-bound organelle in eukaryotic cells involved in lipid metabolism, including β-oxidation of fatty acids. The human genetic disorder X-linked adrenoleukodystrophy (X-ALD is caused by mutations in the ABCD1 gene (encoding ALDP, a peroxisomal half ATP-binding cassette [ABC] transporter. This disease is characterized by defective peroxisomal β-oxidation and a large accumulation of very long-chain fatty acids in brain white matter, adrenal cortex, and testis. ALDP forms a homodimer proposed to be the functional transporter, whereas the peroxisomal transporter in yeast is a heterodimer comprising two half ABC transporters, Pxa1p and Pxa2p, both orthologs of human ALDP. While the carboxyl-terminal domain of ALDP is engaged in dimerization, it remains unknown whether the same region is involved in the interaction between Pxa1p and Pxa2p.Using a yeast two-hybrid assay, we found that the carboxyl-terminal region (CT of Pxa2p, but not of Pxa1p, is required for their interaction. Further analysis indicated that the central part of the CT (designated CT2 of Pxa2p was indispensable for its interaction with the carboxyl terminally truncated Pxa1_NBD. An interaction between the CT of Pxa2p and Pxa1_NBD was not detected, but could be identified in the presence of Pxa2_NBD-CT1. A single mutation of two conserved residues (aligned with X-ALD-associated mutations at the same positions in ALDP in the CT2 of the Pxa2_NBD-CT protein impaired its interaction with Pxa1_NBD or Pxa1_NBD-CT, resulting in a mutant protein that exhibited a proteinase K digestion profile different from that of the wild-type protein. Functional analysis of these mutant proteins on oleate plates indicated that they were defective in transporter function.The CT of Pxa2p is involved in its interaction with Pxa1p and in transporter function. This concept may be applied to human ALDP studies, helping to establish the pathological mechanism for CT-related X

  19. ABC transporters in the CNS - an inventory.

    Science.gov (United States)

    Hartz, A M S; Bauer, B

    2011-04-01

    In the present review we provide a summary of ATP-binding cassette (ABC) transporters in the central nervous system (CNS). Our review is focused on transporters of the ABC A, B, C, D, and G families that have been detected in the cells of the neurovascular unit/blood-brain barrier including brain capillary endothelial cells, pericytes, astrocytes, and neurons, as well as in other brain cells, such as microglia, oligodendrocytes, and choroid plexus epithelial cells. In this review, we provide an overview, organized by ABC family, of transporter expression, localization, and function. We summarize recent findings on ABC transporter regulation in the CNS and address the role of ABC transporters in CNS diseases including brain cancer, seizures/epilepsy, and Alzheimer's disease. Finally, we discuss new therapeutic strategies focused on ABC transporters in CNS disease.

  20. Current advances on ABC drug transporters in fish.

    Science.gov (United States)

    Luckenbach, Till; Fischer, Stephan; Sturm, Armin

    2014-09-01

    Most members of the large ATP-binding cassette (ABC) gene family are transporters involved in substrate translocation across biological membranes. In eukaryotes, ABC proteins functioning as drug transporters are located in the plasma membrane and mediate the cellular efflux of a wide range of organic chemicals, with some transporters also transporting certain metals. As the enhanced expression of ABC drug transporters can confer multidrug resistance (MDR) to cancers and multixenobiotic resistance (MXR) to organisms from polluted habitats, these ABC family members are also referred to as MDR or MXR proteins. In mammals, ABC drug transporters show predominant expression in tissues involved in excretion or constituting internal or external body boundaries, where they facilitate the excretion of chemicals and their metabolites, and limit chemical uptake and penetration into "sanctuary" sites of the body. Available knowledge about ABC proteins is still limited in teleost fish, a large vertebrate group of high ecological and economic importance. Using transport activity measurements and immunochemical approaches, early studies demonstrated similarities in the tissue distribution of ABC drug transporters between teleosts and mammals, suggesting conserved roles of the transporters in the biochemical defence against toxicants. Recently, the availability of teleost genome assemblies has stimulated studies of the ABC family in this taxon. This review summarises the current knowledge regarding the genetics, functional properties, physiological function, and ecotoxicological relevance of teleostean ABC transporters. The available literature is reviewed with emphasis on recent studies addressing the tissue distribution, substrate spectrum, regulation, physiological function and phylogenetic origin of teleostean ABC transporters. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Bioinformatic survey of ABC transporters in dermatophytes.

    Science.gov (United States)

    Gadzalski, Marek; Ciesielska, Anita; Stączek, Paweł

    2016-01-15

    ATP binding cassette (ABC) transporters constitute a very large and ubiquitous superfamily of membrane proteins. They are responsible for ATP hydrolysis driven translocation of countless substrates. Being a very old and diverse group of proteins present in all organisms they share a common feature, which is the presence of an evolutionary conservative nucleotide binding domain (NBD)--the engine that drives the transport. Another common domain is a transmembrane domain (TMD) which consists of several membrane-spanning helices. This part of protein is substrate-specific, thus it is much more variable. ABC transporters are known for driving drug efflux in many pathogens and cancer cells, therefore they are the subject of extensive studies. There are many examples of conferring a drug resistance phenotype in fungal pathogens by ABC transporters, however, little is known about these proteins in dermatophytes--a group of fungi causing superficial mycoses. So far only a single ABC transporter has been extensively studied in this group of pathogens. We analyzed available genomic sequences of seven dermatophyte species in order to provide an insight into dermatophyte ABC protein inventory. Phylogenetic studies of ABC transporter genes and their products were conducted and included ABC transporters of other fungi. Our results show that each dermatophyte genome studied possesses a great variety of ABC transporter genes. Detailed analysis of selected genes and their products indicates that relatively recent duplication of ABC transporter genes could lead to novel substrate specificity. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. ABC transporters in megakaryopoiesis and platelet activity.

    Science.gov (United States)

    Wang, Wei; Buitrago, Lorena; Wang, Ying

    2017-08-01

    ATP-binding cassette (ABC) is a family of transporters that facilitates the translocation of substrates across cell membrane using its ATPase subunit. These transporters have key roles in multidrug resistance, lipid homeostasis, antigen processing, immunity, cell proliferation and hematopoiesis. Some ABC transporters are selectively expressed on megakaryocyte progenitor, megakaryocyte and its cellular fragment platelet. However, the role of ABC transporters in hemostasis and thrombosis were not well explored until recently. Studies of both human genetic diseases and genetically-manipulated animal models have greatly improved our understanding of ABC transporters in regulating hematopoiesis particularly megakaryopoiesis and/or platelet activity. Human genome wide association studies (GWAS) have also unraveled the association between ABC transporters and thrombopoiesis in general population. Therefore, this review aims to summarize the recent advances in our understanding of how ABC transporters regulate megakaryopoiesis and platelet activity, the underlining mechanisms and their association with atherosclerosis and atherothrombosis. Last, the emerging therapeutic targets to slow down atherosclerosis development and prevent atherothrombosis via ABC transporters or downstream pathways will also be discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. ABC Transport Proteins in Cardiovascular Disease-A Brief Summary.

    Science.gov (United States)

    Schumacher, Toni; Benndorf, Ralf A

    2017-04-06

    Adenosine triphosphate (ATP)-binding cassette (ABC) transporters may play an important role in the pathogenesis of atherosclerotic vascular diseases due to their involvement in cholesterol homeostasis, blood pressure regulation, endothelial function, vascular inflammation, as well as platelet production and aggregation. In this regard, ABC transporters, such as ABCA1, ABCG5 and ABCG8, were initially found to be responsible for genetically-inherited syndromes like Tangier diseases and sitosterolemia. These findings led to the understanding of those transporter's function in cellular cholesterol efflux and thereby also linked them to atherosclerosis and cardiovascular diseases (CVD). Subsequently, further ABC transporters, i.e., ABCG1, ABCG4, ABCB6, ABCC1, ABCC6 or ABCC9, have been shown to directly or indirectly affect cellular cholesterol efflux, the inflammatory response in macrophages, megakaryocyte proliferation and thrombus formation, as well as vascular function and blood pressure, and may thereby contribute to the pathogenesis of CVD and its complications. Furthermore, ABC transporters, such as ABCB1, ABCC2 or ABCG2, may affect the safety and efficacy of several drug classes currently in use for CVD treatment. This review will give a brief overview of ABC transporters involved in the process of atherogenesis and CVD pathology. It also aims to briefly summarize the role of ABC transporters in the pharmacokinetics and disposition of drugs frequently used to treat CVD and CVD-related complications.

  4. ABC Transporters in Cancer Stem Cells: Beyond Chemoresistance.

    Science.gov (United States)

    Begicevic, Romana-Rea; Falasca, Marco

    2017-11-08

    The efficacy of chemotherapy is one of the main challenges in cancer treatment and one of the major obstacles to overcome in achieving lasting remission and a definitive cure in patients with cancer is the emergence of cancer resistance. Indeed, drug resistance is ultimately accountable for poor treatment outcomes and tumour relapse. There are various molecular mechanisms involved in multidrug resistance, such as the change in the activity of membrane transporters primarily belonging to the ATP binding cassette (ABC) transporter family. In addition, it has been proposed that this common feature could be attributed to a subpopulation of slow-cycling cancer stem cells (CSCs), endowed with enhanced tumorigenic potential and multidrug resistance. CSCs are characterized by the overexpression of specific surface markers that vary in different cancer cell types. Overexpression of ABC transporters has been reported in several cancers and more predominantly in CSCs. While the major focus on the role played by ABC transporters in cancer is polarized by their involvement in chemoresistance, emerging evidence supports a more active role of these proteins, in which they release specific bioactive molecules in the extracellular milieu. This review will outline our current understanding of the role played by ABC transporters in CSCs, how their expression is regulated and how they support the malignant metabolic phenotype. To summarize, we suggest that the increased expression of ABC transporters in CSCs may have precise functional roles and provide the opportunity to target, particularly these cells, by using specific ABC transporter inhibitors.

  5. ABC Transporters in Cancer Stem Cells: Beyond Chemoresistance

    Directory of Open Access Journals (Sweden)

    Romana-Rea Begicevic

    2017-11-01

    Full Text Available The efficacy of chemotherapy is one of the main challenges in cancer treatment and one of the major obstacles to overcome in achieving lasting remission and a definitive cure in patients with cancer is the emergence of cancer resistance. Indeed, drug resistance is ultimately accountable for poor treatment outcomes and tumour relapse. There are various molecular mechanisms involved in multidrug resistance, such as the change in the activity of membrane transporters primarily belonging to the ATP binding cassette (ABC transporter family. In addition, it has been proposed that this common feature could be attributed to a subpopulation of slow-cycling cancer stem cells (CSCs, endowed with enhanced tumorigenic potential and multidrug resistance. CSCs are characterized by the overexpression of specific surface markers that vary in different cancer cell types. Overexpression of ABC transporters has been reported in several cancers and more predominantly in CSCs. While the major focus on the role played by ABC transporters in cancer is polarized by their involvement in chemoresistance, emerging evidence supports a more active role of these proteins, in which they release specific bioactive molecules in the extracellular milieu. This review will outline our current understanding of the role played by ABC transporters in CSCs, how their expression is regulated and how they support the malignant metabolic phenotype. To summarize, we suggest that the increased expression of ABC transporters in CSCs may have precise functional roles and provide the opportunity to target, particularly these cells, by using specific ABC transporter inhibitors.

  6. Polymorphism in ABC transporter genes of Dirofilaria immitis

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    Thangadurai Mani

    2017-08-01

    Full Text Available Dirofilaria immitis, a filarial nematode, causes dirofilariasis in dogs, cats and occasionally in humans. Prevention of the disease has been mainly by monthly use of the macrocyclic lactone (ML endectocides during the mosquito transmission season. Recently, ML resistance has been confirmed in D. immitis and therefore, there is a need to find new classes of anthelmintics. One of the mechanisms associated with ML resistance in nematodes has been the possible role of ATP binding cassette (ABC transporters in reducing drug concentrations at receptor sites. ABC transporters, mainly from sub-families B, C and G, may contribute to multidrug resistance (MDR by active efflux of drugs out of the cell. Gene products of ABC transporters may thus serve as the targets for agents that may modulate susceptibility to drugs, by inhibiting drug transport. ABC transporters are believed to be involved in a variety of physiological functions critical to the parasite, such as sterol transport, and therefore may also serve as the target for drugs that can act as anthelmintics on their own. Knowledge of polymorphism in these ABC transporter genes in nematode parasites could provide useful information for the process of drug design. We have identified 15 ABC transporter genes from sub-families A, B, C and G, in D. immitis, by comparative genomic approaches and analyzed them for polymorphism. Whole genome sequencing data from four ML susceptible (SUS and four loss of efficacy (LOE pooled populations were used for single nucleotide polymorphism (SNP genotyping. Out of 231 SNPs identified in those 15 ABC transporter genes, 89 and 75 of them were specific to the SUS or LOE populations, respectively. A few of the SNPs identified may affect gene expression, protein function, substrate specificity or resistance development and may be useful for transporter inhibitor/anthelmintic drug design, or in order to anticipate resistance development. Keywords: Dirofilaria immitis

  7. In vitro characterization of ABC transporters involved in the absorption and distribution of liensinine and its analogs.

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    Yu, Lushan; Shen, Qi; Zhou, Quan; Jiang, Huidi; Bi, Huichang; Huang, Min; Zhou, Hui; Zeng, Su

    2013-11-25

    Lotus plumule, the dried young cotyledon and radicle of the Nelumbo nucifera Gaertn. (Fam. Nymphaeaceae) ripe seed, is a famous Traditional Chinese Medicine to remove heat from the heart, anchor the mind, improve seminal emission, and arrest bleeding for centuries in China. Liensinine and its analogs neferine and isoliensinine are the major active components in lotus plumule. Aim of the study is to investigate the association of liensinine, neferine, and isoliensinine with efflux transporters. Caco-2, MDCK, MDCK-MDR1, and MDCK-MRP2 were used as cell models for the transcellular transport and accumulation studies. The results obtained in Caco-2 cells suggested that P-glycoprotein (P-gp) might be involved in transcellular transport. Cellular accumulation and transport experiments were further performed in MDCK-MDR1 cells. GF120918 and cyclosporine A were found to completely inhibit the efflux, and the net efflux ratios of these alkaloids exhibited saturation over the concentration range. No significant differences in liensinine accumulation and transport were observed between MDCK and MDCK-MRP2 cells. These results demonstrated that liensinine, neferine, and isoliensinine are substrates of P-gp, whereas MRP2 is not involved in the transport process, suggesting that P-gp might be responsible for the absorption and distribution of the 3 alkaloids. © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. ABC-B transporter genes in Dirofilaria immitis.

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    Bourguinat, Catherine; Che, Hua; Mani, Thangadurai; Keller, Kathy; Prichard, Roger K

    2016-08-01

    Dirofilaria immitis is a filarial nematode causing infection and heartworm disease in dogs and other canids, cats, and occasionally in humans. Prevention with macrocyclic lactones (ML) is recommended during the mosquito transmission season. Recently, ML resistance has been reported. ABC-B transporter genes are thought to be involved in the mechanism of ML resistance in other nematodes. This study aimed to identify all the ABC-B transporter genes in D. immitis using as a reference the nDi.2.2 D. immitis whole genome, which is not completely annotated. Using bioinformatic tools and PCR amplification on pooled D. immitis genomic DNA and on pooled cDNA, nine ABC transporter genes including one pseudogene were characterized. Bioinformatic and phylogenetic analyses allowed identification of three P-glycoproteins (Pgps) (Dim-pgp-3 Dim-pgp-10, Dim-pgp-11), of two ABC-B half transporter genes (one ortholog of Cel-haf-4 and Cel-haf-9; and one ortholog of Cel-haf-1 and Cel-haf-3), of one ABC half transporter gene (ortholog of Cel-haf-5) that contained an ABC-C motif, and of one additional half transporter that would require functional study for characterization. The number of ABC-B transporter genes identified was lower than in Caenorhabditis elegans and Haemonchus contortus. Further studies are needed to understand their possible role in ML resistance in D. immitis. These ABC transporters constitute a base for ML resistance investigation in D. immitis and advance our understanding of the molecular biology of this parasite. Copyright © 2016. Published by Elsevier Ltd.

  9. Polymorphism in ABC transporter genes of Dirofilaria immitis.

    Science.gov (United States)

    Mani, Thangadurai; Bourguinat, Catherine; Prichard, Roger K

    2017-08-01

    Dirofilaria immitis, a filarial nematode, causes dirofilariasis in dogs, cats and occasionally in humans. Prevention of the disease has been mainly by monthly use of the macrocyclic lactone (ML) endectocides during the mosquito transmission season. Recently, ML resistance has been confirmed in D. immitis and therefore, there is a need to find new classes of anthelmintics. One of the mechanisms associated with ML resistance in nematodes has been the possible role of ATP binding cassette (ABC) transporters in reducing drug concentrations at receptor sites. ABC transporters, mainly from sub-families B, C and G, may contribute to multidrug resistance (MDR) by active efflux of drugs out of the cell. Gene products of ABC transporters may thus serve as the targets for agents that may modulate susceptibility to drugs, by inhibiting drug transport. ABC transporters are believed to be involved in a variety of physiological functions critical to the parasite, such as sterol transport, and therefore may also serve as the target for drugs that can act as anthelmintics on their own. Knowledge of polymorphism in these ABC transporter genes in nematode parasites could provide useful information for the process of drug design. We have identified 15 ABC transporter genes from sub-families A, B, C and G, in D. immitis, by comparative genomic approaches and analyzed them for polymorphism. Whole genome sequencing data from four ML susceptible (SUS) and four loss of efficacy (LOE) pooled populations were used for single nucleotide polymorphism (SNP) genotyping. Out of 231 SNPs identified in those 15 ABC transporter genes, 89 and 75 of them were specific to the SUS or LOE populations, respectively. A few of the SNPs identified may affect gene expression, protein function, substrate specificity or resistance development and may be useful for transporter inhibitor/anthelmintic drug design, or in order to anticipate resistance development. Copyright © 2017 The Authors. Published by

  10. ABC transporters in the liver fluke Opisthorchis felineus.

    Science.gov (United States)

    Mordvinov, Viatcheslav A; Ershov, Nikita I; Pirozhkova, Darya S; Pakharukov, Yuri V; Pakharukova, Maria Y

    2017-09-01

    ATP-binding cassette transporters (ABC transporters) are essential components of normal cellular physiological machinery in all eukaryotic and prokaryotic species, including parasites. Some ABC transporters, e.g., P-glycoproteins, are involved in the efflux of toxins and xenobiotics from the cell. At present, nothing is known about ABC transporter genes in epidemiologically important liver flukes from the Opisthorchiidae family, including European liver fluke Opisthorchis felineus. Opisthorchiasis caused by O. felineus is a serious public health problem on the territory of Russia and other Eastern European countries. ABC drug transporters are attractive objects of research on molecular markers of resistance and on ways to potentiate sensitivity to anthelmintics through suppression of the transporters themselves with specific inhibitors. Here we aimed at the identification of ABC transporters in the O. felineus transcriptome and identification of P-glycoproteins. In addition, our aim was to assess ABC transcript abundance in the RNA-seq data, to study the mRNA expression of P-glycoprotein genes by Droplet Digital PCR throughout the life cycle of O. felineus, and to test the gene induction in response to xenobiotics or anthelminthic agents. We found 23 nucleotide sequences encoding ABC transporters belonging to different subfamilies, including four sequences of P-glycoproteins. According to the transcript abundance in the RNA-seq data, one of P-glycoproteins (P4) has the highest expression among all ABC genes in the adult worm. P-glycoproteins showed substantially differential mRNA expression throughout the fluke life cycle, with high expression in the adult worms. Putative activity of P-glycoproteins as xenobiotic efflux pumps was found to be linked to the excretory system of O. felineus and to be inhibited by verapamil or tariquidar. Thus, ABC drug transporters in the liver fluke O. felineus are functionally active, indicating that ABC drug transporters are likely

  11. Importance of ABC Transporters in Drug Development.

    Science.gov (United States)

    Benadiba, Marcel; Maor, Yehoshua

    2016-01-01

    ATP-binding cassette (ABC) transporters are a huge family of ATP-dependent transmembrane proteins whose main function is exporting or importing substances or molecules through the cell membranes, plasma cell membrane, or inner membranes in organelles. They fulfill these functions by maintaining cell integrity, metabolism, and homeostasis. They are expressed in a variety of tissues as they transport numerous essential compounds including lipids and other signaling molecules. ABC transporters became widely studied since the discovery of their ability to carry a multitude of xenobiotics, including therapeutic drugs, and in light of the fact that they represent a hurdle for the treatment of resistant cancers. In contrast, the role of ABC transporters in neurological diseases like Alzheimer`s and Parkinson`s, depression, schizophrenia, and epilepsy remains controversial and their mechanism of action in these pathologies remains elusive, thus hindering the implementation of therapies aimed at modulating the functions of these transporters. To date, a number of natural and synthetic compounds are known to act as inhibitors, substrates, and even inducers of these transporters, being able to modulate their expression and/or function; however, their implication as therapeutic agents is far from reaching wide clinical utilization. This review highlights the importance of overcoming the challenges posed by ABC transporters in drug development.

  12. Asymmetric switching in a homodimeric ABC transporter: a simulation study.

    Directory of Open Access Journals (Sweden)

    Jussi Aittoniemi

    2010-04-01

    Full Text Available ABC transporters are a large family of membrane proteins involved in a variety of cellular processes, including multidrug and tumor resistance and ion channel regulation. Advances in the structural and functional understanding of ABC transporters have revealed that hydrolysis at the two canonical nucleotide-binding sites (NBSs is co-operative and non-simultaneous. A conserved core architecture of bacterial and eukaryotic ABC exporters has been established, as exemplified by the crystal structure of the homodimeric multidrug exporter Sav1866. Currently, it is unclear how sequential ATP hydrolysis arises in a symmetric homodimeric transporter, since it implies at least transient asymmetry at the NBSs. We show by molecular dynamics simulation that the initially symmetric structure of Sav1866 readily undergoes asymmetric transitions at its NBSs in a pre-hydrolytic nucleotide configuration. MgATP-binding residues and a network of charged residues at the dimer interface are shown to form a sequence of putative molecular switches that allow ATP hydrolysis only at one NBS. We extend our findings to eukaryotic ABC exporters which often consist of two non-identical half-transporters, frequently with degeneracy substitutions at one of their two NBSs. Interestingly, many residues involved in asymmetric conformational switching in Sav1866 are substituted in degenerate eukaryotic NBS. This finding strengthens recent suggestions that the interplay of a consensus and a degenerate NBS in eukaroytic ABC proteins pre-determines the sequence of hydrolysis at the two NBSs.

  13. ABC transporters in fish species: a review

    Directory of Open Access Journals (Sweden)

    Marta eFerreira

    2014-07-01

    Full Text Available ATP-binding cassette (ABC proteins were first recognized for their role in multidrug resistance (MDR in chemotherapeutic treatments, which is a major impediment for the successful treatment of many forms of malignant tumors in humans. These proteins, highly conserved throughout vertebrate species, were later related to cellular detoxification and accounted as responsible for protecting aquatic organisms from xenobiotic insults in the so-called multixenobiotic resistance mechanism (MXR. In recent years, research on these proteins in aquatic species has highlighted their importance in the detoxification mechanisms in fish thus it is of extreme added value to continue these studies. Several transporters have been pointed out as relevant in the ecotoxicological context associated to the transport of xenobiotics, such as P-glycoproteins (Pgps, multidrug-resistance-associated proteins (MRPs 1-5 and breast resistance associated protein (BCRP. In mammals, several nuclear receptors have been identified as mediators of phase I and II metabolizing enzymes and ABC transporters. In aquatic species, knowledge on co-regulation of detoxification mechanism is scarce and needs to be addressed. The interaction of emergent contaminants, with chemosensitizer potential, with ABC transporters in aquatic organisms can compromise detoxification processes and have population effects and should be studied in more detail. This review intends to summarize the recent advances in research on MXR mechanisms in fish species, focusing in 1 regulation and functioning of ABC proteins; 2 cooperation with phase I and II biotransformation enzymes; and 3 ecotoxicological relevance and information on emergent pollutants with ability to modulate ABC transporters expression and activity. Several lines of evidence are clear suggesting the important role of these transporters in detoxification mechanisms and must be further investigated in fish.

  14. Energy Coupling Factor-Type ABC Transporters for Vitamin Uptake in Prokaryotes

    NARCIS (Netherlands)

    Erkens, Guus B.; Dosz-Majsnerowska, Maria; ter Beek, Josy; Slotboom, Dirk Jan

    2012-01-01

    Energy coupling factor (ECF) transporters are a subgroup of ATP-binding cassette (ABC) transporters involved in the uptake of vitamins and micronutrients in prokaryotes. In contrast to classical ABC importers, ECF transporters do not make use of water-soluble substrate binding proteins or domains

  15. Phenotypic, Proteomic, and Genomic Characterization of a Putative ABC-Transporter Permease Involved in Listeria monocytogenes Biofilm Formation

    DEFF Research Database (Denmark)

    Zhu, Xinna; Liu, Weibing; Lametsch, René

    2011-01-01

    Δ1771 was more sensitive to Triton X-100 and less resistant to cationic antibiotics, which might be explained by the down-regulation of dlt operon in this deletant and the fact that dlt involves the incorporation of D-alanine residues into lipoteichoic acids, resulting in a positive net charge...

  16. Functional analysis of candidate ABC transporter proteins for sitosterol transport

    DEFF Research Database (Denmark)

    Albrecht, C; Elliott, J I; Sardini, A

    2002-01-01

    Two ATP-binding cassette (ABC) proteins, ABCG5 and ABCG8, have recently been associated with the accumulation of dietary cholesterol in the sterol storage disease sitosterolemia. These two 'half-transporters' are assumed to dimerize to form the complete sitosterol transporter which reduces...... the absorption of sitosterol and related molecules in the intestine by pumping them back into the lumen. Although mutations altering ABCG5 and ABCG8 are found in affected patients, no functional demonstration of sitosterol transport has been achieved. In this study, we investigated whether other ABC transporters......-specific ABC transporters have acquired specificity to exclude sitosterol and related sterols like cholesterol presumably because the abundance of cholesterol in the membrane would interfere with their action; in consequence, specific transporters have evolved to handle these sterols....

  17. Abc1: a new ABC transporter from the fission yeast Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Christensen, P U; Davis, K; Nielsen, O

    1997-01-01

    We have isolated the abc1 gene from the fission yeast Schizosaccharomyces pombe. Sequence analysis suggests that the Abc1 protein is a member of the ABC superfamily of transporters and is composed of two structurally homologous halves, each consisting of a hydrophobic region of six transmembrane...... domains and a hydrophilic region containing one ATP-binding site. The abc1 gene appears to be expressed under all growth conditions but gene disruption experiments indicate that it is not essential for growth. The sequence of the abc1 gene has been deposited in the EMBL data library under the Accession...

  18. The ABC gene family in arthropods: comparative genomics and role in insecticide transport and resistance.

    Science.gov (United States)

    Dermauw, Wannes; Van Leeuwen, Thomas

    2014-02-01

    About a 100 years ago, the Drosophila white mutant marked the birth of Drosophila genetics. The white gene turned out to encode the first well studied ABC transporter in arthropods. The ABC gene family is now recognized as one of the largest transporter families in all kingdoms of life. The majority of ABC proteins function as primary-active transporters that bind and hydrolyze ATP while transporting a large diversity of substrates across lipid membranes. Although extremely well studied in vertebrates for their role in drug resistance, less is known about the role of this family in the transport of endogenous and exogenous substances in arthropods. The ABC families of five insect species, a crustacean and a chelicerate have been annotated in some detail. We conducted a thorough phylogenetic analysis of the seven arthropod and human ABC protein subfamilies, to infer orthologous relationships that might suggest conserved function. Most orthologous relationships were found in the ABCB half transporter, ABCD, ABCE and ABCF subfamilies, but specific expansions within species and lineages are frequently observed and discussed. We next surveyed the role of ABC transporters in the transport of xenobiotics/plant allelochemicals and their involvement in insecticide resistance. The involvement of ABC transporters in xenobiotic resistance in arthropods is historically not well documented, but an increasing number of studies using unbiased differential gene expression analysis now points to their importance. We give an overview of methods that can be used to link ABC transporters to resistance. ABC proteins have also recently been implicated in the mode of action and resistance to Bt toxins in Lepidoptera. Given the enormous interest in Bt toxicology in transgenic crops, such findings will provide an impetus to further reveal the role of ABC transporters in arthropods. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Inventory, assembly and analysis of Bacillus subtilis ABC transport systems.

    Science.gov (United States)

    Quentin, Y; Fichant, G; Denizot, F

    1999-04-02

    We have undertaken the inventory and assembly of the ATP binding cassette (ABC) transporter systems in the complete genome of Bacillus subtilis. We combined the identification of the three protein partners that compose an ABC transporter (nucleotide-binding domain, NBD; membrane spanning domain, MSD; and solute-binding protein, SBP) with constraints on the genetic organization. This strategy allowed the identification of 86 NBDs in 78 proteins, 103 MSD proteins and 37 SBPs. The analysis of transcriptional units allows the reconstruction of 59 ABC transporters, which include at least one NBD and one MSD. A particular class of five dimeric ATPases was not associated to MSD partners and is assumed to be involved either in macrolide resistance or regulation of translation elongation. In addition, we have detected five genes encoding ATPases without any gene coding for MSD protein in their neighborhood and 11 operons that encode only the membrane and solute-binding proteins. On the bases of similarities, three ATP-binding proteins are proposed to energize ten incomplete systems, suggesting that one ATPase may be recruited by more than one transporter. Finally, we estimate that the B. subtilis genome encodes for at least 78 ABC transporters that have been split in 38 importers and 40 extruders. The ABC systems have been further classified into 11 sub-families according to the tree obtained from the NBDs and the clustering of the MSDs and the SBPs. Comparisons with Escherichia coli show that the extruders are over-represented in B. subtilis, corresponding to an expansion of the sub-families of antibiotic and drug resistance systems. Copyright 1999 Academic Press.

  20. Functional analysis of candidate ABC transporter proteins for sitosterol transport

    DEFF Research Database (Denmark)

    Albrecht, C; Elliott, J I; Sardini, A

    2002-01-01

    Two ATP-binding cassette (ABC) proteins, ABCG5 and ABCG8, have recently been associated with the accumulation of dietary cholesterol in the sterol storage disease sitosterolemia. These two 'half-transporters' are assumed to dimerize to form the complete sitosterol transporter which reduces the ab...

  1. Isolation and Characterization of the Colletotrichum acutatum ABC Transporter CaABC1

    Directory of Open Access Journals (Sweden)

    Suyoung Kim

    2014-12-01

    Full Text Available Fungi tolerate exposure to various abiotic stresses, including cytotoxic compounds and fungicides, via their ATP-driven efflux pumps belonging to ATP-binding cassette (ABC transporters. To clarify the molecular basis of interaction between the fungus and various abiotic stresses including fungicides, we constructed a cDNA library from germinated conidia of Colletotrichum acutatum, a major anthracnose pathogen of pepper (Capsicum annum L.. Over 1,000 cDNA clones were sequenced, of which single clone exhibited significant nucleotide sequence homology to ABC transporter genes. We isolated three fosmid clones containing the C. acutatum ABC1 (CaABC1 gene in full-length from genomic DNA library screening. The CaABC1 gene consists of 4,059 bp transcript, predicting a 1,353-aa protein. The gene contains the typical ABC signature and Walker A and B motifs. The 5′-flanking region contains a CAAT motif, a TATA box, and a Kozak region. Phylogenetic and structural analysis suggested that the CaABC1 is a typical ABC transporter gene highly conserved in various fungal species, as well as in Chromista, Metazoans, and Viridiplantae. We also found that CaABC1 was up-regulated during conidiation and a minimal medium condition. Moreover, CaABC1 was induced in iprobenfos, kresoxim-methyl, thiophanate-methyl, and hygromycin B. These results demonstrate that CaABC1 is necessary for conidiation, abiotic stress, and various fungicide resistances. These results will provide the basis for further study on the function of ABC transporter genes in C. acutatum.

  2. Reduction of U(VI) by the deep subsurface bacterium, Thermus scotoductus SA-01, and the involvement of the ABC transporter protein.

    Science.gov (United States)

    Cason, Errol Duncan; Piater, Lizelle Ann; van Heerden, Esta

    2012-02-01

    In this study we investigated the effect of uranium on the growth of the bacterium Thermus scotoductus strain SA-01 as well as the whole cell U(VI) reduction capabilities of the organism. Also, site-directed mutagenesis confirmed the identity of a protein capable of a possible alternative mechanism of U(VI) reduction. SA-01 can grow aerobically in up to 1.25 mM uranium and has the capability to reduce low levels of U(VI) in under 20 h. TEM analysis performed on cells exposed to uranium showed extracellular and membrane-bound accumulation of uranium. The reductase-like protein was surprisingly identified as a peptide ABC transporter, peptide-binding protein. This study showcases the concept of protein promiscuity, where this protein with a distinct function in situ can also have the unintended function of a reactant for the reduction of U(VI). Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Diversity of ABC transporter genes across the plant kingdom and their potential utility in biotechnology.

    Science.gov (United States)

    Lane, Thomas S; Rempe, Caroline S; Davitt, Jack; Staton, Margaret E; Peng, Yanhui; Soltis, Douglas Edward; Melkonian, Michael; Deyholos, Michael; Leebens-Mack, James H; Chase, Mark; Rothfels, Carl J; Stevenson, Dennis; Graham, Sean W; Yu, Jun; Liu, Tao; Pires, J Chris; Edger, Patrick P; Zhang, Yong; Xie, Yinlong; Zhu, Ying; Carpenter, Eric; Wong, Gane Ka-Shu; Stewart, C Neal

    2016-05-31

    The ATP-binding cassette (ABC) transporter gene superfamily is ubiquitous among extant organisms and prominently represented in plants. ABC transporters act to transport compounds across cellular membranes and are involved in a diverse range of biological processes. Thus, the applicability to biotechnology is vast, including cancer resistance in humans, drug resistance among vertebrates, and herbicide and other xenobiotic resistance in plants. In addition, plants appear to harbor the highest diversity of ABC transporter genes compared with any other group of organisms. This study applied transcriptome analysis to survey the kingdom-wide ABC transporter diversity in plants and suggest biotechnology applications of this diversity. We utilized sequence similarity-based informatics techniques to infer the identity of ABC transporter gene candidates from 1295 phylogenetically-diverse plant transcriptomes. A total of 97,149 putative (approximately 25 % were full-length) ABC transporter gene members were identified; each RNA-Seq library (plant sample) had 88 ± 30 gene members. As expected, simpler organisms, such as algae, had fewer unique members than vascular land plants. Differences were also noted in the richness of certain ABC transporter subfamilies. Land plants had more unique ABCB, ABCC, and ABCG transporter gene members on average (p plant groups (p plant groups. An increase in the number of gene family members present in the ABCB, ABCC, and ABCD transporter subfamilies may indicate an expansion of the ABC transporter superfamily among green land plants, which include all crop species. The striking difference between the number of ABCA subfamily transporter gene members between ferns and other plant taxa is surprising and merits further investigation. Discussed is the potential exploitation of ABC transporters in plant biotechnology, with an emphasis on crops.

  4. Transport mechanism of acyl-CoA into peroxisomes by a peroxisomal ABC transporter, ABCD1

    OpenAIRE

    Agustina, Rina

    2016-01-01

    Transport mechanism of acyl-CoA into peroxisomes by a peroxisomal ABC protein, ABCD1 ABCD1, belonging to the ABC protein subfamily D, is aperoxisomal membrane protein and involves in the transport of very long chain fatty acid (VLCFA)-CoA into peroxisomes. Its mutation causes X-linked adrenoleukodystophy; an inborn error of peroxisomal VLCFA ??-oxidation. It has been reported that COMATOSE, a homolog of human ABCD1 in plant possess acyl-CoA thioesterase (ACOT) activity and t...

  5. Human ATP-binding cassette (ABC transporter family

    Directory of Open Access Journals (Sweden)

    Vasiliou Vasilis

    2009-04-01

    Full Text Available Abstract There exist four fundamentally different classes of membrane-bound transport proteins: ion channels; transporters; aquaporins; and ATP-powered pumps. ATP-binding cassette (ABC transporters are an example of ATP-dependent pumps. ABC transporters are ubiquitous membrane-bound proteins, present in all prokaryotes, as well as plants, fungi, yeast and animals. These pumps can move substrates in (influx or out (efflux of cells. In mammals, ABC transporters are expressed predominantly in the liver, intestine, blood-brain barrier, blood-testis barrier, placenta and kidney. ABC proteins transport a number of endogenous substrates, including inorganic anions, metal ions, peptides, amino acids, sugars and a large number of hydrophobic compounds and metabolites across the plasma membrane, and also across intracellular membranes. The human genome contains 49 ABC genes, arranged in eight subfamilies and named via divergent evolution. That ABC genes are important is underscored by the fact that mutations in at least I I of these genes are already known to cause severe inherited diseases (eg cystic fibrosis and X-linked adrenoleukodystrophy [X-ALD]. ABC transporters also participate in the movement of most drugs and their metabolites across cell surface and cellular organelle membranes; thus, defects in these genes can be important in terms of cancer therapy, pharmacokinetics and innumerable pharmacogenetic disorders.

  6. Structural basis for the mechanism of ABC transporters.

    Science.gov (United States)

    Beis, Konstantinos

    2015-10-01

    The ATP-binding cassette (ABC) transporters are primary transporters that couple the energy stored in adenosine triphosphate (ATP) to the movement of molecules across the membrane. ABC transporters can be divided into exporters and importers; importers mediate the uptake of essential nutrients into cells and are found predominantly in prokaryotes whereas exporters transport molecules out of cells or into organelles and are found in all organisms. ABC exporters have been linked with multi-drug resistance in both bacterial and eukaryotic cells. ABC transporters are powered by the hydrolysis of ATP and transport their substrate via the alternating access mechanism, whereby the protein alternates between a conformation in which the substrate-binding site is accessible from the outside of the membrane, outward-facing and one in which it is inward-facing. In this mini-review, the structures of different ABC transporter types in different conformations are presented within the context of the alternating access mechanism and how they have shaped our current understanding of the mechanism of ABC transporters. © 2015 Authors; published by Portland Press Limited.

  7. Current Understanding of Interactions between Nanoparticles and ABC Transporters in Cancer Cells.

    Science.gov (United States)

    Yin, Jian; Deng, Xudong; Zhang, Jie; Lin, Jun

    2018-03-14

    Adenosine triphosphate-binding cassette (ABC) transporters-mediated multidrug resistance (MDR) remains as a obstacle for effective cancer therapy. Nanoparticles (NPs)-based delivery systems are promising to overcome MDR, but only a few of them have been accepted for clinical treatment, due to characteristics such as insufficient transportation and potential toxicity. In this respect, mounting attention has been attracted towards interactions between NPs and ABC transporters, which hold a key role in the treatment of multidrug-resistant cancer and NP toxicity. In this review article, current knowledge on the involvement of ABC transporters in MDR and their inhibitors is provided. More importantly, recent literatures about the interactions between NPs and ABC transporters are summarized here. Organic and inorganic NPs inhibit the function of ABC transporters based on distinct mechanisms. The effects of organic NPs are caused by several excipients like surfactants, polymers, lipids and cyclodextrin, whereas inorganic NPs act as substrates of ABC transporters and competitively inhibit the efflux of drugs. Based on these interesting phenomena, a more thorough understanding of the specific mechanisms is necessary and essential in the hope to develop more efficient NPs to overcome MDR and decrease environmental toxicity of NPs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. ABC transporter research: going strong 40 years on.

    Science.gov (United States)

    Theodoulou, Frederica L; Kerr, Ian D

    2015-10-01

    In most organisms, ABC transporters constitute one of the largest families of membrane proteins. In humans, their functions are diverse and underpin numerous key physiological processes, as well as being causative factors in a number of clinically relevant pathologies. Advances in our understanding of these diseases have come about through combinations of genetic and protein biochemical investigations of these transporters and the power of in vitro and in vivo investigations is helping to develop genotype-phenotype understanding. However, the importance of ABC transporter research goes far beyond human biology; microbial ABC transporters are of great interest in terms of understanding virulence and drug resistance and industrial biotechnology researchers are exploring the potential of prokaryotic ABC exporters to increase the capacity of synthetic biology systems. Plant ABC transporters play important roles in transport of hormones, xenobiotics, metals and secondary metabolites, pathogen responses and numerous aspects of development, all of which are important in the global food security area. For 3 days in Chester, this Biochemical Society Focused Meeting brought together researchers with diverse experimental approaches and with different fundamental questions, all of which are linked by the commonality of ABC transporters. © 2015 Authors.

  9. Export of recombinant proteins in Escherichia coli using ABC transporter with an attached lipase ABC transporter recognition domain (LARD

    Directory of Open Access Journals (Sweden)

    Moon Yuseok

    2009-01-01

    Full Text Available Abstract Background ATP binding cassette (ABC transporter secretes the protein through inner and outer membranes simultaneously in gram negative bacteria. Thermostable lipase (TliA of Pseudomonas fluorescens SIK W1 is secreted through the ABC transporter. TliA has four glycine-rich repeats (GGXGXD in its C-terminus, which appear in many ABC transporter-secreted proteins. From a homology model of TliA derived from the structure of P. aeruginosa alkaline protease (AprA, lipase ABC transporter domains (LARDs were designed for the secretion of fusion proteins. Results The LARDs included four glycine-rich repeats comprising a β-roll structure, and were added to the C-terminus of test proteins. Either Pro-Gly linker or Factor Xa site was added between fusion proteins and LARDs. We attached different length of LARDs such as LARD0, LARD1 or whole TliA (the longest LARD to three types of proteins; green fluorescent protein (GFP, epidermal growth factor (EGF and cytoplasmic transduction peptide (CTP. These fusion proteins were expressed in Escherichia coli together with ABC transporter of either P. fluorescens or Erwinia chrysanthemi. Export of fusion proteins with the whole TliA through the ABC transporter was evident on the basis of lipase enzymatic activity. Upon supplementation of E. coli with ABC transporter, GFP-LARDs and EGF-LARDs were excreted into the culture supernatant. Conclusion The LARDs or whole TliA were attached to C-termini of model proteins and enabled the export of the model proteins such as GFP and EGF in E. coli supplemented with ABC transporter. These results open the possibility for the extracellular production of recombinant proteins in Pseudomonas using LARDs or TliA as a C-terminal signal sequence.

  10. Transportomics: screening for substrates of ABC transporters in body fluids using vesicular transport assays

    NARCIS (Netherlands)

    Krumpochova, Petra; Sapthu, Sunny; Brouwers, Jos F.; de Haas, Marcel; de Vos, Ric; Borst, Piet; van de Wetering, Koen

    2012-01-01

    The ATP-binding cassette (ABC) genes encode the largest family of transmembrane proteins. ABC transporters translocate a wide variety of substrates across membranes, but their physiological function is often incompletely understood. We describe a new method to study the substrate spectrum of ABC

  11. Comparison of mechanistic transport cycle models of ABC exporters.

    Science.gov (United States)

    Szöllősi, Dániel; Rose-Sperling, Dania; Hellmich, Ute A; Stockner, Thomas

    2018-04-01

    ABC (ATP binding cassette) transporters, ubiquitous in all kingdoms of life, carry out essential substrate transport reactions across cell membranes. Their transmembrane domains bind and translocate substrates and are connected to a pair of nucleotide binding domains, which bind and hydrolyze ATP to energize import or export of substrates. Over four decades of investigations into ABC transporters have revealed numerous details from atomic-level structural insights to their functional and physiological roles. Despite all these advances, a comprehensive understanding of the mechanistic principles of ABC transporter function remains elusive. The human multidrug resistance transporter ABCB1, also referred to as P-glycoprotein (P-gp), is one of the most intensively studied ABC exporters. Using ABCB1 as the reference point, we aim to compare the dominating mechanistic models of substrate transport and ATP hydrolysis for ABC exporters and to highlight the experimental and computational evidence in their support. In particular, we point out in silico studies that enhance and complement available biochemical data. "This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain." Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  12. Glycolysis inhibition inactivates ABC transporters to restore drug sensitivity in malignant cells.

    Directory of Open Access Journals (Sweden)

    Ayako Nakano

    Full Text Available Cancer cells eventually acquire drug resistance largely via the aberrant expression of ATP-binding cassette (ABC transporters, ATP-dependent efflux pumps. Because cancer cells produce ATP mostly through glycolysis, in the present study we explored the effects of inhibiting glycolysis on the ABC transporter function and drug sensitivity of malignant cells. Inhibition of glycolysis by 3-bromopyruvate (3BrPA suppressed ATP production in malignant cells, and restored the retention of daunorubicin or mitoxantrone in ABC transporter-expressing, RPMI8226 (ABCG2, KG-1 (ABCB1 and HepG2 cells (ABCB1 and ABCG2. Interestingly, although side population (SP cells isolated from RPMI8226 cells exhibited higher levels of glycolysis with an increased expression of genes involved in the glycolytic pathway, 3BrPA abolished Hoechst 33342 exclusion in SP cells. 3BrPA also disrupted clonogenic capacity in malignant cell lines including RPMI8226, KG-1, and HepG2. Furthermore, 3BrPA restored cytotoxic effects of daunorubicin and doxorubicin on KG-1 and RPMI8226 cells, and markedly suppressed subcutaneous tumor growth in combination with doxorubicin in RPMI8226-implanted mice. These results collectively suggest that the inhibition of glycolysis is able to overcome drug resistance in ABC transporter-expressing malignant cells through the inactivation of ABC transporters and impairment of SP cells with enhanced glycolysis as well as clonogenic cells.

  13. The therapeutic potential of targeting ABC transporters to combat multi-drug resistance.

    Science.gov (United States)

    Bugde, Piyush; Biswas, Riya; Merien, Fabrice; Lu, Jun; Liu, Dong-Xu; Chen, Mingwei; Zhou, Shufeng; Li, Yan

    2017-05-01

    Most disseminated cancers remain fatal despite the availability of a variety of conventional and novel treatments including surgery, chemotherapy, radiotherapy, immunotherapy, and biologically targeted therapy. A major factor responsible for the failure of chemotherapy in the treatment of cancer is the development of multidrug resistance (MDR). The overexpression of various ABC transporters in cancer cells can efficiently remove the anticancer drug from the cell, thus causing the drug to lose its effect. Areas covered: In this review, we summarised the ongoing research related to the mechanism, function, and regulation of ABC transporters. We integrated our current knowledge at different levels from molecular biology to clinical trials. We also discussed potential therapeutic strategies of targeting ABC transporters to reverse MDR in cancer cells. Expert opinion: Involvement of various ABC transporters to cancer MDR lays the foundation for developing tailored therapies that can overcome MDR. An ideal MDR reversal agent should have broad-spectrum ABC-transporter inhibitory activity, be potent, have good pharmacokinetics, have no trans-stimulation effects, and have low or no toxicity. Alternatively, nanotechnology-based drug delivery systems containing both the cytotoxic drug and reversing agent may represent a useful approach to reversing MDR with minimal off-target toxicity.

  14. Tissue-Specific Transcript Profiling for ABC Transporters in the Sequestering Larvae of the Phytophagous Leaf Beetle Chrysomela populi

    Science.gov (United States)

    Gretscher, René R.; Groth, Marco; Boland, Wilhelm; Burse, Antje

    2014-01-01

    Background Insects evolved ingenious adaptations to use extraordinary food sources. Particularly, the diet of herbivores enriched with noxious plant secondary metabolites requires detoxification mechanisms. Sequestration, which involves the uptake, transfer, and concentration of occasionally modified phytochemicals into specialized tissues or hemolymph, is one of the most successful detoxification strategies found in most insect orders. Due to the ability of ATP-binding cassette (ABC) carriers to transport a wide range of molecules including phytochemicals and xenobiotics, it is highly likely that they play a role in this sequestration process. To shed light on the role of ABC proteins in sequestration, we describe an inventory of putative ABC transporters in various tissues in the sequestering juvenile poplar leaf beetle, Chrysomela populi. Results In the transcriptome of C. populi, we predicted 65 ABC transporters. To link the proteins with a possible function, we performed comparative phylogenetic analyses with ABC transporters of other insects and of humans. While tissue-specific profiling of each ABC transporter subfamily suggests that ABCB, C and G influence the plant metabolite absorption in the gut, ABCC with 14 members is the preferred subfamily responsible for the excretion of these metabolites via Malpighian tubules. Moreover, salicin, which is sequestered from poplar plants, is translocated into the defensive glands for further deterrent production. In these glands and among all identified ABC transporters, an exceptionally high transcript level was observed only for Cpabc35 (Cpmrp). RNAi revealed the deficiency of other ABC pumps to compensate the function of CpABC35, demonstrating its key role during sequestration. Conclusion We provide the first comprehensive phylogenetic study of the ABC family in a phytophagous beetle species. RNA-seq data from different larval tissues propose the importance of ABC pumps to achieve a homeostasis of plant

  15. Tissue-specific transcript profiling for ABC transporters in the sequestering larvae of the phytophagous leaf beetle Chrysomela populi.

    Directory of Open Access Journals (Sweden)

    Anja S Strauss

    Full Text Available Insects evolved ingenious adaptations to use extraordinary food sources. Particularly, the diet of herbivores enriched with noxious plant secondary metabolites requires detoxification mechanisms. Sequestration, which involves the uptake, transfer, and concentration of occasionally modified phytochemicals into specialized tissues or hemolymph, is one of the most successful detoxification strategies found in most insect orders. Due to the ability of ATP-binding cassette (ABC carriers to transport a wide range of molecules including phytochemicals and xenobiotics, it is highly likely that they play a role in this sequestration process. To shed light on the role of ABC proteins in sequestration, we describe an inventory of putative ABC transporters in various tissues in the sequestering juvenile poplar leaf beetle, Chrysomela populi.In the transcriptome of C. populi, we predicted 65 ABC transporters. To link the proteins with a possible function, we performed comparative phylogenetic analyses with ABC transporters of other insects and of humans. While tissue-specific profiling of each ABC transporter subfamily suggests that ABCB, C and G influence the plant metabolite absorption in the gut, ABCC with 14 members is the preferred subfamily responsible for the excretion of these metabolites via Malpighian tubules. Moreover, salicin, which is sequestered from poplar plants, is translocated into the defensive glands for further deterrent production. In these glands and among all identified ABC transporters, an exceptionally high transcript level was observed only for Cpabc35 (Cpmrp. RNAi revealed the deficiency of other ABC pumps to compensate the function of CpABC35, demonstrating its key role during sequestration.We provide the first comprehensive phylogenetic study of the ABC family in a phytophagous beetle species. RNA-seq data from different larval tissues propose the importance of ABC pumps to achieve a homeostasis of plant-derived compounds and

  16. Tissue-specific transcript profiling for ABC transporters in the sequestering larvae of the phytophagous leaf beetle Chrysomela populi.

    Science.gov (United States)

    Strauss, Anja S; Wang, Ding; Stock, Magdalena; Gretscher, René R; Groth, Marco; Boland, Wilhelm; Burse, Antje

    2014-01-01

    Insects evolved ingenious adaptations to use extraordinary food sources. Particularly, the diet of herbivores enriched with noxious plant secondary metabolites requires detoxification mechanisms. Sequestration, which involves the uptake, transfer, and concentration of occasionally modified phytochemicals into specialized tissues or hemolymph, is one of the most successful detoxification strategies found in most insect orders. Due to the ability of ATP-binding cassette (ABC) carriers to transport a wide range of molecules including phytochemicals and xenobiotics, it is highly likely that they play a role in this sequestration process. To shed light on the role of ABC proteins in sequestration, we describe an inventory of putative ABC transporters in various tissues in the sequestering juvenile poplar leaf beetle, Chrysomela populi. In the transcriptome of C. populi, we predicted 65 ABC transporters. To link the proteins with a possible function, we performed comparative phylogenetic analyses with ABC transporters of other insects and of humans. While tissue-specific profiling of each ABC transporter subfamily suggests that ABCB, C and G influence the plant metabolite absorption in the gut, ABCC with 14 members is the preferred subfamily responsible for the excretion of these metabolites via Malpighian tubules. Moreover, salicin, which is sequestered from poplar plants, is translocated into the defensive glands for further deterrent production. In these glands and among all identified ABC transporters, an exceptionally high transcript level was observed only for Cpabc35 (Cpmrp). RNAi revealed the deficiency of other ABC pumps to compensate the function of CpABC35, demonstrating its key role during sequestration. We provide the first comprehensive phylogenetic study of the ABC family in a phytophagous beetle species. RNA-seq data from different larval tissues propose the importance of ABC pumps to achieve a homeostasis of plant-derived compounds and offer a basis for

  17. ABC transporters in Arthropods: genomic comparison and role in insecticide transport and resistance

    NARCIS (Netherlands)

    Dermauw, W.; Van Leeuwen, T.

    2014-01-01

    About a 100 years ago, the Drosophila white mutant marked the birth of Drosophila genetics. The white gene turned out to encode the first well studied ABC transporter in arthropods. The ABC gene family is now recognized as one of the largest transporter families in all kingdoms of life. The majority

  18. Phosphorylation is required for the pathogen defense function of the Arabidopsis PEN3 ABC transporter

    Science.gov (United States)

    The Arabidopsis PEN3 ABC transporter accumulates at sites of pathogen detection, where it is involved in defense against multiple pathogens. Perception of PAMPs by pattern recognition receptors initiates recruitment of PEN3 and also leads to PEN3 phosphorylation at multiple amino acid residues. Whet...

  19. ABC transporter genes and risk of type 2 diabetes

    DEFF Research Database (Denmark)

    Schou, Jesper; Tybjærg-Hansen, Anne; Møller, Holger Jon

    2012-01-01

    Alterations of pancreatic β-cell cholesterol content may contribute to β-cell dysfunction. Two important determinants of intracellular cholesterol content are the ATP-binding cassette (ABC) transporters A1 (ABCA1) and -G1 (ABCG1). Whether genetic variation in ABCA1 and ABCG1 predicts risk of type 2...... diabetes in the general population is unknown....

  20. ABC transporters of the wheat pathogen Mycosphaerella graminicola

    NARCIS (Netherlands)

    Zwiers, L.H.

    2002-01-01

    A TP- b inding c assette (ABC) transporters belong to one of the largest protein families known. They play a role in numerous vital processes in the cell and are characterised by their

  1. ABC transporters van Botrytis cinerea in biotische en abiotische interacties

    NARCIS (Netherlands)

    Schoonbeek, H.

    2005-01-01

    Op 29 november 2004 promoveerde Henk-jan Schoonbeek aan Wageningen Universiteit op het proefschrift getiteld 'ABC transporters from Botrytis cinerea in biotic and abiotic interactions'. Promotor was Prof. dr. ir. P.J.G.M. de Wit en co-promotor was dr.ir. M.A. de Waard, leerstoelgroep Fytopathologie,

  2. ABC transporters from Botrytis cinerea in biotic and abiotic interactions

    NARCIS (Netherlands)

    Schoonbeek, H.

    2004-01-01

    Botrytis cinereais the causal agent of grey mould disease on a wide variety of crop plants. It is relatively insensitive to natural and synthetic fungitoxic compounds. This thesis describes how ABC (ATP-binding cassette) transporters contribute to protection by actively

  3. Energy Coupling Efficiency in the Type I ABC Transporter GlnPQ.

    Science.gov (United States)

    Lycklama A Nijeholt, Jelger A; Vietrov, Ruslan; Schuurman-Wolters, Gea K; Poolman, Bert

    2018-03-16

    Solute transport via ATP binding cassette (ABC) importers involves receptor-mediated substrate binding, which is followed by ATP-driven translocation of the substrate across the membrane. How these steps are exactly initiated and coupled, and how much ATP it takes to complete a full transport cycle, are subject of debate. Here, we reconstitute the ABC importer GlnPQ in nanodiscs and in proteoliposomes and determine substrate-(in)dependent ATP hydrolysis and transmembrane transport. We determined the conformational states of the substrate-binding domains (SBDs) by single-molecule Förster resonance energy transfer measurements. We find that the basal ATPase activity (ATP hydrolysis in the absence of substrate) is mainly caused by the docking of the closed-unliganded state of the SBDs onto the transporter domain of GlnPQ and that, unlike glutamine, arginine binds both SBDs but does not trigger their closing. Furthermore, comparison of the ATPase activity in nanodiscs with glutamine transport in proteoliposomes shows that the stoichiometry of ATP per substrate is close to two. These findings help understand the mechanism of transport and the energy coupling efficiency in ABC transporters with covalently linked SBDs, which may aid our understanding of Type I ABC importers in general. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Overcoming ABC transporter-mediated multidrug resistance: Molecular mechanisms and novel therapeutic drug strategies.

    Science.gov (United States)

    Li, Wen; Zhang, Han; Assaraf, Yehuda G; Zhao, Kun; Xu, Xiaojun; Xie, Jinbing; Yang, Dong-Hua; Chen, Zhe-Sheng

    2016-07-01

    Multidrug resistance is a key determinant of cancer chemotherapy failure. One of the major causes of multidrug resistance is the enhanced efflux of drugs by membrane ABC transporters. Targeting ABC transporters projects a promising approach to eliminating or suppressing drug resistance in cancer treatment. To reveal the functional mechanisms of ABC transporters in drug resistance, extensive studies have been conducted from identifying drug binding sites to elucidating structural dynamics. In this review article, we examined the recent crystal structures of ABC proteins to depict the functionally important structural elements, such as domains, conserved motifs, and critical amino acids that are involved in ATP-binding and drug efflux. We inspected the drug-binding sites on ABC proteins and the molecular mechanisms of various substrate interactions with the drug binding pocket. While our continuous battle against drug resistance is far from over, new approaches and technologies have emerged to push forward our frontier. Most recent developments in anti-MDR strategies include P-gp inhibitors, RNA-interference, nano-medicines, and delivering combination strategies. With the advent of the 'Omics' era - genomics, epigenomics, transcriptomics, proteomics, and metabolomics - these disciplines play an important role in fighting the battle against chemoresistance by further unraveling the molecular mechanisms of drug resistance and shed light on medical therapies that specifically target MDR. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. The role of ABC transporters of the blood-brain barrier in opioid tolerance development

    Directory of Open Access Journals (Sweden)

    Kamila Środa-Pomianek

    2018-02-01

    Full Text Available Opioids constitute an important group of drugs used in chronic pain treatment, e.g. cancer pain. Unfortunately, the development of the organism’s tolerance to the analgesic activity of opioids, the tendency to develop addictions and undesirable side effects are the main causes reducing opioid efficiency in chronic pain treatment. Among many mechanisms connected to emerging of opioid resistance the ATP-binding cassette (ABC transporters present at the blood-brain barrier may play an important role. These transporter proteins, especially P-glycoprotein (ABCB1, MDR1, affect pharmacokinetics of many drugs and xenobiotics that are their substrates. ABC transporters reduce cellular uptake of drugs and/or increase their export from brain tissue to blood. Substrate specificity of P-glycoprotein is extremely wide and comprises many structurally and functionally unrelated compounds. What is interesting, substrate specificity of P-glycoprotein overlaps to a great extent the specificity of the isoforms of cytochrome P450 involved in drug metabolism. In the present review, the ABC proteins-mediated transport of opioids was discussed as well as the mechanisms of transport regulation. Cellular metabolism of various opioid drugs and the role of ABC transporters in their absorption, distribution and elimination were also described.

  6. Genome-wide identification, characterization and phylogenetic analysis of 50 catfish ATP-binding cassette (ABC transporter genes.

    Directory of Open Access Journals (Sweden)

    Shikai Liu

    Full Text Available Although a large set of full-length transcripts was recently assembled in catfish, annotation of large gene families, especially those with duplications, is still a great challenge. Most often, complexities in annotation cause mis-identification and thereby much confusion in the scientific literature. As such, detailed phylogenetic analysis and/or orthology analysis are required for annotation of genes involved in gene families. The ATP-binding cassette (ABC transporter gene superfamily is a large gene family that encodes membrane proteins that transport a diverse set of substrates across membranes, playing important roles in protecting organisms from diverse environment.In this work, we identified a set of 50 ABC transporters in catfish genome. Phylogenetic analysis allowed their identification and annotation into seven subfamilies, including 9 ABCA genes, 12 ABCB genes, 12 ABCC genes, 5 ABCD genes, 2 ABCE genes, 4 ABCF genes and 6 ABCG genes. Most ABC transporters are conserved among vertebrates, though cases of recent gene duplications and gene losses do exist. Gene duplications in catfish were found for ABCA1, ABCB3, ABCB6, ABCC5, ABCD3, ABCE1, ABCF2 and ABCG2.The whole set of catfish ABC transporters provide the essential genomic resources for future biochemical, toxicological and physiological studies of ABC drug efflux transporters. The establishment of orthologies should allow functional inferences with the information from model species, though the function of lineage-specific genes can be distinct because of specific living environment with different selection pressure.

  7. Hepatic ABC transporters and triglyceride metabolism.

    Science.gov (United States)

    Parks, John S; Chung, Soonkyu; Shelness, Gregory S

    2012-06-01

    Elevated plasma triglyceride and reduced HDL concentrations are prominent features of metabolic syndrome and type 2 diabetes. Individuals with Tangier disease also have elevated plasma triglyceride concentrations and very low HDL, resulting from mutations in ATP-binding cassette transporter A1 (ABCA1), an integral membrane protein that facilitates nascent HDL particle assembly. Past studies attributed the inverse relationship between plasma HDL and triglyceride to intravascular lipid exchange and catabolic events. However, recent studies also suggest that hepatic signaling and lipid mobilization and secretion may explain how HDL affects plasma triglyceride concentrations. Hepatocyte-specific ABCA1 knockout mice have markedly reduced plasma HDL and a two-fold increase in triglyceride due to failure to assemble nascent HDL particles by hepatocytes, causing increased catabolism of HDL apolipoprotein A-I and increased hepatic production of triglyceride-enriched VLDL. In-vitro studies suggest that nascent HDL particles may induce signaling to decrease triglyceride secretion. Inhibition of microRNA 33 expression in nonhuman primates augments hepatic ABCA1, genes involved in fatty acid oxidation, and decreases expression of lipogenic genes, causing increased plasma HDL and decreased triglyceride levels. New evidence suggests potential mechanisms by which hepatic ABCA1-mediated nascent HDL formation regulates VLDL-triglyceride production and contributes to the inverse relationship between plasma HDL and triglyceride.

  8. Tonoplast-localized Abc2 transporter mediates phytochelatin accumulation in vacuoles and confers cadmium tolerance.

    Science.gov (United States)

    Mendoza-Cózatl, David G; Zhai, Zhiyang; Jobe, Timothy O; Akmakjian, Garo Z; Song, Won-Yong; Limbo, Oliver; Russell, Matthew R; Kozlovskyy, Volodymyr I; Martinoia, Enrico; Vatamaniuk, Olena K; Russell, Paul; Schroeder, Julian I

    2010-12-24

    Phytochelatins mediate tolerance to heavy metals in plants and some fungi by sequestering phytochelatin-metal complexes into vacuoles. To date, only Schizosaccharomyces pombe Hmt1 has been described as a phytochelatin transporter and attempts to identify orthologous phytochelatin transporters in plants and other organisms have failed. Furthermore, recent data indicate that the hmt1 mutant accumulates significant phytochelatin levels in vacuoles, suggesting that unidentified phytochelatin transporters exist in fungi. Here, we show that deletion of all vacuolar ABC transporters abolishes phytochelatin accumulation in S. pombe vacuoles and abrogates (35)S-PC(2) uptake into S. pombe microsomal vesicles. Systematic analysis of the entire S. pombe ABC transporter family identified Abc2 as a full-size ABC transporter (ABCC-type) that mediates phytochelatin transport into vacuoles. The S. pombe abc1 abc2 abc3 abc4 hmt1 quintuple and abc2 hmt1 double mutant show no detectable phytochelatins in vacuoles. Abc2 expression restores phytochelatin accumulation into vacuoles and suppresses the cadmium sensitivity of the abc quintuple mutant. A novel, unexpected, function of Hmt1 in GS-conjugate transport is also shown. In contrast to Hmt1, Abc2 orthologs are widely distributed among kingdoms and are proposed as the long-sought vacuolar phytochelatin transporters in plants and other organisms.

  9. Regulation of ABC transporters blood-brain barrier: the good, the bad, and the ugly.

    Science.gov (United States)

    Miller, David S

    2015-01-01

    The brain capillary endothelial cells that constitute the blood-brain barrier express multiple ABC transport proteins on the luminal, blood-facing, plasma membrane. These transporters function as ATP-driven efflux pumps for xenobiotics and endogenous metabolites. High expression of these ABC transporters at the barrier is a major obstacle to the delivery of therapeutics, including chemotherapeutics, to the CNS. Here, I review the signals that alter ABC transporter expression and transport function with an emphasis on P-glycoprotein, Mrp2, and breast cancer resistance protein (BCRP), the efflux transporters for which we have the most detailed picture of regulation. Recent work shows that transporter protein expression can be upregulated in response to inflammatory and oxidative stress, therapeutic drugs, diet, and persistent environmental pollutants; as a consequence, drug delivery to the brain is reduced (potentially bad and ugly). In contrast, basal transport activity of P-glycoprotein and BCRP can be reduced through complex signaling pathways that involve events in and on the brain capillary endothelial cells. Targeting these signaling events provides opportunities to rapidly and reversibly increase brain accumulation of drugs that are substrates for the transporters (potentially good). The clinical usefulness of targeting signaling to reduce efflux transporter activity and improve drug delivery to the CNS remains to be established. © 2015 Elsevier Inc. All rights reserved.

  10. ABC Transporters and the Alzheimer’s Disease Enigma

    Directory of Open Access Journals (Sweden)

    Andrea eWolf

    2012-06-01

    Full Text Available Alzheimer’s disease (AD is considered the disease of the 21st century. With a 10-fold increase in global incidence over the past 100 years, AD is now reaching epidemic proportions and by all projections, AD patient numbers will continue to rise. Despite intense research efforts, AD remains a mystery and effective therapies are still unavailable. This represents an unmet need resulting in clinical, social, and economic problems.Over the last decade, a new AD research focus has emerged: ATP-binding cassette (ABC transporters. In this article, we provide an overview of the ABC transporters ABCA1, ABCA2, P-glycoprotein (ABCB1, Mrp1 (ABCC1 and BCRP (ABCG2, all of which are expressed in the brain and have been implicated in AD. We summarize recent findings on the role of these five transporters in AD, and discuss their potential to serve as therapeutic targets.

  11. Transportomics: screening for substrates of ABC transporters in body fluids using vesicular transport assays.

    NARCIS (Netherlands)

    Krumpochova, P; Sapthu, S.; Brouwers, J.F.H.M.; de Haas, M.; de Vos, R.; Borst, P.; van de Wetering, K.

    2013-01-01

    ABSTRACT The ATP-binding cassette (ABC) genes encode the largest family of transmembrane proteins. ABC transporters translocate a wide variety of substrates across membranes, but their physiological function is often incompletely understood. We describe a new method to study the substrate spectrum

  12. [Peroxisomal ABC transporters and X-linked adrenoleukodystrophy].

    Science.gov (United States)

    Geillon, Flore; Trompier, Doriane; Gondcaille, Catherine; Lizard, Gérard; Savary, Stéphane

    2012-12-01

    X-linked adrenoleukodystrophy (X-ALD) is a complex neurodegenerative disease associated with mutations in the ABCD1 gene, which encodes for a peroxisomal ABC transporter. Thanks to the efforts of the ELA foundation and to the recent successes of gene therapy published in Science in 2009, X-ALD is better known but still remains poorly understood. The exact role of ABCD1 and its homologs, as well as the exact link between the biochemical and metabolic peroxisomal defects and the clinical symptoms of the disease remain to be elucidated. This review summarizes the knowledge concerning the subfamily D of the ABC transporter family and concerning X-ALD, the most frequent peroxisomal disorder. © 2012 médecine/sciences – Inserm / SRMS.

  13. Evidence for an ABC-Type Riboflavin Transporter System in Pathogenic Spirochetes

    Science.gov (United States)

    Deka, Ranjit K.; Brautigam, Chad A.; Biddy, Brent A.; Liu, Wei Z.; Norgard, Michael V.

    2013-01-01

    ABSTRACT Bacterial transporter proteins are involved in the translocation of many essential nutrients and metabolites. However, many of these key bacterial transport systems remain to be identified, including those involved in the transport of riboflavin (vitamin B2). Pathogenic spirochetes lack riboflavin biosynthetic pathways, implying reliance on obtaining riboflavin from their hosts. Using structural and functional characterizations of possible ligand-binding components, we have identified an ABC-type riboflavin transport system within pathogenic spirochetes. The putative lipoprotein ligand-binding components of these systems from three different spirochetes were cloned, hyperexpressed in Escherichia coli, and purified to homogeneity. Solutions of all three of the purified recombinant proteins were bright yellow. UV-visible spectra demonstrated that these proteins were likely flavoproteins; electrospray ionization mass spectrometry and thin-layer chromatography confirmed that they contained riboflavin. A 1.3-Å crystal structure of the protein (TP0298) encoded by Treponema pallidum, the syphilis spirochete, demonstrated that the protein’s fold is similar to the ligand-binding components of ABC-type transporters. The structure also revealed other salient details of the riboflavin binding site. Comparative bioinformatics analyses of spirochetal genomes, coupled with experimental validation, facilitated the discovery of this new ABC-type riboflavin transport system(s). We denote the ligand-binding component as riboflavin uptake transporter A (RfuA). Taken together, it appears that pathogenic spirochetes have evolved an ABC-type transport system (RfuABCD) for survival in their host environments, particularly that of the human host. PMID:23404400

  14. A multidrug ABC transporter with a taste for salt.

    Directory of Open Access Journals (Sweden)

    Saroj Velamakanni

    2009-07-01

    Full Text Available LmrA is a multidrug ATP-binding cassette (ABC transporter from Lactococcus lactis with no known physiological substrate, which can transport a wide range of chemotherapeutic agents and toxins from the cell. The protein can functionally replace the human homologue ABCB1 (also termed multidrug resistance P-glycoprotein MDR1 in lung fibroblast cells. Even though LmrA mediates ATP-dependent transport, it can use the proton-motive force to transport substrates, such as ethidium bromide, across the membrane by a reversible, H(+-dependent, secondary-active transport reaction. The mechanism and physiological context of this reaction are not known.We examined ion transport by LmrA in electrophysiological experiments and in transport studies using radioactive ions and fluorescent ion-selective probes. Here we show that LmrA itself can transport NaCl by a similar secondary-active mechanism as observed for ethidium bromide, by mediating apparent H(+-Na(+-Cl(- symport. Remarkably, LmrA activity significantly enhances survival of high-salt adapted lactococcal cells during ionic downshift.The observations on H(+-Na(+-Cl(- co-transport substantiate earlier suggestions of H(+-coupled transport by LmrA, and indicate a novel link between the activity of LmrA and salt stress. Our findings demonstrate the relevance of investigations into the bioenergetics of substrate translocation by ABC transporters for our understanding of fundamental mechanisms in this superfamily. This study represents the first use of electrophysiological techniques to analyze substrate transport by a purified multidrug transporter.

  15. Functional expression and characterization of plant ABC transporters in Xenopus laevis oocytes for transport engineering purposes

    DEFF Research Database (Denmark)

    Xu, Deyang; Veres, Dorottya; Belew, Zeinu Mussa

    2016-01-01

    Transport engineering in bioengineering is aimed at efficient export of the final product to reduce toxicity and feedback inhibition and to increase yield. The ATP-binding cassette (ABC) transporters with their highly diverse substrate specificity and role in cellular efflux are potentially...... suitable in transport engineering approaches, although their size and high number of introns make them notoriously difficult to clone. Here, we report a novel in planta “exon engineering” strategy for cloning of full-length coding sequence of ABC transporters followed by methods for biochemical...... provided will hopefully contribute to more successful transport engineering in synthetic biology....

  16. Obstacles to Brain Tumor Therapy: Key ABC Transporters

    Directory of Open Access Journals (Sweden)

    Juwina Wijaya

    2017-11-01

    Full Text Available The delivery of cancer chemotherapy to treat brain tumors remains a challenge, in part, because of the inherent biological barrier, the blood–brain barrier. While its presence and role as a protector of the normal brain parenchyma has been acknowledged for decades, it is only recently that the important transporter components, expressed in the tightly knit capillary endothelial cells, have been deciphered. These transporters are ATP-binding cassette (ABC transporters and, so far, the major clinically important ones that functionally contribute to the blood–brain barrier are ABCG2 and ABCB1. A further limitation to cancer therapy of brain tumors or brain metastases is the blood–tumor barrier, where tumors erect a barrier of transporters that further impede drug entry. The expression and regulation of these two transporters at these barriers, as well as tumor derived alteration in expression and/or mutation, are likely obstacles to effective therapy.

  17. Structural and mechanistic insights into ABC-type ECF transporters for vitamin uptake

    NARCIS (Netherlands)

    Dosz-Majsnerowska, Maria

    2014-01-01

    Dit proefschrift gaat over de relatie tussen de structuur en het mechanisme van ABC-type ECF transporters voor vitamines, uit de bacterie Lactococcus lactis. Energy-Coupling Factor (ECF) transporters vormen een subgroep van de ATP-binding cassette (ABC) transporters en zijn betrokken bij de opname

  18. Predictive Structure and Topology of Peroxisomal ATP-Binding Cassette (ABC) Transporters

    Science.gov (United States)

    Andreoletti, Pierre; Raas, Quentin; Gondcaille, Catherine; Cherkaoui-Malki, Mustapha; Trompier, Doriane; Savary, Stéphane

    2017-01-01

    The peroxisomal ATP-binding Cassette (ABC) transporters, which are called ABCD1, ABCD2 and ABCD3, are transmembrane proteins involved in the transport of various lipids that allow their degradation inside the organelle. Defective ABCD1 leads to the accumulation of very long-chain fatty acids and is associated with a complex and severe neurodegenerative disorder called X-linked adrenoleukodystrophy (X-ALD). Although the nucleotide-binding domain is highly conserved and characterized within the ABC transporters family, solid data are missing for the transmembrane domain (TMD) of ABCD proteins. The lack of a clear consensus on the secondary and tertiary structure of the TMDs weakens any structure-function hypothesis based on the very diverse ABCD1 mutations found in X-ALD patients. Therefore, we first reinvestigated thoroughly the structure-function data available and performed refined alignments of ABCD protein sequences. Based on the 2.85  Å resolution crystal structure of the mitochondrial ABC transporter ABCB10, here we propose a structural model of peroxisomal ABCD proteins that specifies the position of the transmembrane and coupling helices, and highlight functional motifs and putative important amino acid residues. PMID:28737695

  19. Predictive Structure and Topology of Peroxisomal ATP-Binding Cassette (ABC Transporters

    Directory of Open Access Journals (Sweden)

    Pierre Andreoletti

    2017-07-01

    Full Text Available The peroxisomal ATP-binding Cassette (ABC transporters, which are called ABCD1, ABCD2 and ABCD3, are transmembrane proteins involved in the transport of various lipids that allow their degradation inside the organelle. Defective ABCD1 leads to the accumulation of very long-chain fatty acids and is associated with a complex and severe neurodegenerative disorder called X-linked adrenoleukodystrophy (X-ALD. Although the nucleotide-binding domain is highly conserved and characterized within the ABC transporters family, solid data are missing for the transmembrane domain (TMD of ABCD proteins. The lack of a clear consensus on the secondary and tertiary structure of the TMDs weakens any structure-function hypothesis based on the very diverse ABCD1 mutations found in X-ALD patients. Therefore, we first reinvestigated thoroughly the structure-function data available and performed refined alignments of ABCD protein sequences. Based on the 2.85  Å resolution crystal structure of the mitochondrial ABC transporter ABCB10, here we propose a structural model of peroxisomal ABCD proteins that specifies the position of the transmembrane and coupling helices, and highlight functional motifs and putative important amino acid residues.

  20. The ABC transporter Rv1272c of Mycobacterium tuberculosis enhances the import of long-chain fatty acids in Escherichia coli.

    Science.gov (United States)

    Martin, Audrey; Daniel, Jaiyanth

    2018-02-05

    Mycobacterium tuberculosis (Mtb), which causes tuberculosis, is capable of accumulating triacylglycerol (TAG) by utilizing fatty acids from host cells. ATP-binding cassette (ABC) transporters are involved in transport processes in all organisms. Among the classical ABC transporters in Mtb none have been implicated in fatty acid import. Since the transport of fatty acids from the host cell is important for dormancy-associated TAG synthesis in the pathogen, mycobacterial ABC transporter(s) could potentially be involved in this process. Based on sequence identities with a bacterial ABC transporter that mediates fatty acid import for TAG synthesis, we identified Rv1272c, a hitherto uncharacterized ABC-transporter in Mtb that also shows sequence identities with a plant ABC transporter involved in fatty acid transport. We expressed Rv1272c in E. coli and show that it enhances the import of radiolabeled fatty acids. We also show that Rv1272c causes a significant increase in the metabolic incorporation of radiolabeled long-chain fatty acids into cardiolipin, a tetra-acylated phospholipid, and phosphatidylglycerol in E. coli. This is the first report on the function of Rv1272c showing that it displays a long-chain fatty acid transport function. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Transmembrane Domain Single-Nucleotide Polymorphisms Impair Expression and Transport Activity of ABC Transporter ABCG2

    NARCIS (Netherlands)

    Sjostedt, N.; Heuvel, J.J.M.W. van den; Koenderink, J.B.; Kidron, H.

    2017-01-01

    PURPOSE: To study the function and expression of nine naturally occurring single-nucleotide polymorphisms (G406R, F431L, S441N, P480L, F489L, M515R, L525R, A528T and T542A) that are predicted to reside in the transmembrane regions of the ABC transporter ABCG2. METHODS: The transport activity of the

  2. Transcriptional expression analysis of ABC efflux transporters and xenobiotic-metabolizing enzymes in the Chinese rare minnow.

    Science.gov (United States)

    Yuan, Lilai; Lv, Biping; Zha, Jinmiao; Wang, Zijian

    2014-05-01

    In the present study, the cDNA fragments of five ABC transporter genes (ABCB1, ABCB11, ABCC1, ABCC2, and ABCG2) in the rare minnow were cloned, and their tissue-specific expression patterns were evaluated across eight rare minnow tissues (liver, gill, intestine, kidney, spleen, brain, skin, and muscle). Furthermore, the transcriptional effects on these ABC transporter genes and five xenobiotic-metabolizing enzyme genes (CYP1A, GSTm, GSTp1, GCLC, and UGT1a) were determined in the rare minnow liver after 12 days of pyrene exposure. Basal expression analysis showed that the tissues with high expression of the ABC transporters included the liver, kidney, and intestine. Moreover, the most highly expressed of the ABC genes were ABCB1 and ABCC2 in all eight of the tissues tested. The ABCB11 gene was almost exclusively expressed in the liver of the rare minnow, whereas ABCC1 and ABCG2 showed weak expression in all eight tissues compared to ABCB1 and ABCC2. Our results provide the first thorough examination of the expression patterns of toxicologically relevant ABC transporters in the rare minnow and serve as a necessary basis for further studies of these ABC transporters in fish. Furthermore, synergistic up-regulation of CYP1A, GSTp1, GCLC, UGT1a, and ABCC2 was observed in the rare minnow liver following pyrene exposure, while GSTm, ABCB1, ABCB11, ABCC1, and ABCG2 were not significantly affected (p ABC transporters by pyrene suggests a possible involvement and cooperation of these genes in the detoxification process in rare minnows. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. A Critical View on ABC Transporters and Their Interacting Partners in Auxin Transport.

    Science.gov (United States)

    Geisler, Markus; Aryal, Bibek; di Donato, Martin; Hao, Pengchao

    2017-10-01

    Different subclasses of ATP-binding cassette (ABC) transporters have been implicated in the transport of native variants of the phytohormone auxin. Here, the putative, individual roles of key members belonging to the ABCB, ABCD and ABCG families, respectively, are highlighted and the knowledge of their assumed expression and transport routes is reviewed and compared with their mutant phenotypes. Protein-protein interactions between ABC transporters and regulatory components during auxin transport are summarized and their importance is critically discussed. There is a focus on the functional interaction between members of the ABCB family and the FKBP42, TWISTED DWARF1, acting as a chaperone during plasma membrane trafficking of ABCBs. Further, the mode and relevance of functional ABCB-PIN interactions is diagnostically re-evaluated. A new nomenclature describing precisely the most likely ABCB-PIN interaction scenarios is suggested. Finally, available tools for the detection and prediction of ABC transporter interactomes are summarized and the potential of future ABC transporter interactome maps is highlighted. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  4. Effect of Oxidative Stress on ABC Transporters: Contribution to Epilepsy Pharmacoresistance

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    Gurpreet Kaur Grewal

    2017-02-01

    Full Text Available Epilepsy is a neurological disorder affecting around 1%–2% of population worldwide and its treatment includes use of antiepileptic drugs to control seizures. Failure to respond to antiepileptic drug therapy is a major clinical problem and over expression of ATP-binding cassette transporters is considered one of the major reasons for pharmacoresistance. In this review, we have summarized the regulation of ABC transporters in response to oxidative stress due to disease and antiepileptic drugs. Further, ketogenic diet and antioxidants were examined for their role in pharmacoresistance. The understanding of signalling pathways and mechanism involved may help in identifying potential therapeutic targets and improving drug response.

  5. The substrate-binding protein in bacterial ABC transporters: dissecting roles in the evolution of substrate specificity.

    Science.gov (United States)

    Maqbool, Abbas; Horler, Richard S P; Muller, Axel; Wilkinson, Anthony J; Wilson, Keith S; Thomas, Gavin H

    2015-10-01

    ATP-binding cassette (ABC) transporters, although being ubiquitous in biology, often feature a subunit that is limited primarily to bacteria and archaea. This subunit, the substrate-binding protein (SBP), is a key determinant of the substrate specificity and high affinity of ABC uptake systems in these organisms. Most prokaryotes have many SBP-dependent ABC transporters that recognize a broad range of ligands from metal ions to amino acids, sugars and peptides. Herein, we review the structure and function of a number of more unusual SBPs, including an ABC transporter involved in the transport of rare furanose forms of sugars and an SBP that has evolved to specifically recognize the bacterial cell wall-derived murein tripeptide (Mtp). Both these examples illustrate that subtle changes in binding-site architecture, including changes in side chains not directly involved in ligand co-ordination, can result in significant alteration of substrate range in novel and unpredictable ways. © 2015 Authors; published by Portland Press Limited.

  6. Identification of ABC transporters acting in vitamin B12metabolism in Caenorhabditis elegans.

    Science.gov (United States)

    McDonald, Megan K; Fritz, Julie-Anne; Jia, Dongxin; Scheuchner, Deborah; Snyder, Floyd F; Stanislaus, Avalyn; Curle, Jared; Li, Liang; Stabler, Sally P; Allen, Robert H; Mains, Paul E; Gravel, Roy A

    2017-12-01

    Vitamin B 12 (cobalamin, Cbl) is a micronutrient essential to human health. Cbl is not utilized as is but must go through complex subcellular and metabolic processing to generate two cofactor forms: methyl-Cbl for methionine synthase, a cytosolic enzyme; and adenosyl-Cbl for methylmalonyl-CoA mutase, a mitochondrial enzyme. Some 10-12 human genes have been identified responsible for the intracellular conversion of Cbl to cofactor forms, including genes that code for ATP-binding cassette (ABC) transporters acting at the lysosomal and plasma membranes. However, the gene for mitochondrial uptake is not known. We hypothesized that ABC transporters should be candidates for other uptake and efflux functions, including mitochondrial transport, and set out to screen ABC transporter mutants for blocks in Cbl utilization using the nematode roundworm Caenorhabditis elegans. Thirty-seven mutant ABC transporters were screened for the excretion of methylmalonic acid (MMA), which should result from loss of Cbl transport into the mitochondria. One mutant, wht-6, showed elevated MMA excretion and reduced [ 14 C]-propionate incorporation, pointing to a functional block in methylmalonyl-CoA mutase. In contrast, the wht-6 mutant appeared to have a normal cytosolic pathway based on analysis of cystathionine excretion, suggesting that cytosolic methionine synthase was functioning properly. Further, the MMA excretion in wht-6 could be partially reversed by including vitamin B 12 in the assay medium. The human ortholog of wht-6 is a member of the G family of ABC transporters. We propose wht-6 as a candidate for the transport of Cbl into mitochondria and suggest that a member of the corresponding ABCG family of ABC transporters has this role in humans. Our ABC transporter screen also revealed that mrp-1 and mrp-2 mutants excreted lower MMA than wild type, suggesting they were concentrating intracellular Cbl, consistent with the cellular efflux defect proposed for the mammalian MRP1 ABC

  7. Hematopoietic stem cells exhibit a specific ABC transporter gene expression profile clearly distinct from other stem cells.

    NARCIS (Netherlands)

    Tang, L.; Bergevoet, S.M.; Gilissen, C.F.H.A.; Witte, T.J.M. de; Jansen, J.H.; Reijden, B.A. van der; Raymakers, R.A.P.

    2010-01-01

    BACKGROUND: ATP-binding cassette (ABC) transporters protect cells against unrelated (toxic) substances by pumping them across cell membranes. Earlier we showed that many ABC transporters are highly expressed in hematopoietic stem cells (HSCs) compared to more committed progenitor cells. The ABC

  8. An ABC transporter mutation is correlated with insect resistance to Bacillus thuringiensis Cry1Ac toxin.

    Directory of Open Access Journals (Sweden)

    Linda J Gahan

    2010-12-01

    Full Text Available Transgenic crops producing insecticidal toxins from Bacillus thuringiensis (Bt are commercially successful in reducing pest damage, yet knowledge of resistance mechanisms that threaten their sustainability is incomplete. Insect resistance to the pore-forming Cry1Ac toxin is correlated with the loss of high-affinity, irreversible binding to the mid-gut membrane, but the genetic factors responsible for this change have been elusive. Mutations in a 12-cadherin-domain protein confer some Cry1Ac resistance but do not block this toxin binding in in vitro assays. We sought to identify mutations in other genes that might be responsible for the loss of binding. We employed a map-based cloning approach using a series of backcrosses with 1,060 progeny to identify a resistance gene in the cotton pest Heliothis virescens that segregated independently from the cadherin mutation. We found an inactivating mutation of the ABC transporter ABCC2 that is genetically linked to Cry1Ac resistance and is correlated with loss of Cry1Ac binding to membrane vesicles. ABC proteins are integral membrane proteins with many functions, including export of toxic molecules from the cell, but have not been implicated in the mode of action of Bt toxins before. The reduction in toxin binding due to the inactivating mutation suggests that ABCC2 is involved in membrane integration of the toxin pore. Our findings suggest that ABC proteins may play a key role in the mode of action of Bt toxins and that ABC protein mutations can confer high levels of resistance that could threaten the continued utilization of Bt-expressing crops. However, such mutations may impose a physiological cost on resistant insects, by reducing export of other toxins such as plant secondary compounds from the cell. This weakness could be exploited to manage this mechanism of Bt resistance in the field.

  9. An ABC transporter mutation is correlated with insect resistance to Bacillus thuringiensis Cry1Ac toxin.

    Science.gov (United States)

    Gahan, Linda J; Pauchet, Yannick; Vogel, Heiko; Heckel, David G

    2010-12-16

    Transgenic crops producing insecticidal toxins from Bacillus thuringiensis (Bt) are commercially successful in reducing pest damage, yet knowledge of resistance mechanisms that threaten their sustainability is incomplete. Insect resistance to the pore-forming Cry1Ac toxin is correlated with the loss of high-affinity, irreversible binding to the mid-gut membrane, but the genetic factors responsible for this change have been elusive. Mutations in a 12-cadherin-domain protein confer some Cry1Ac resistance but do not block this toxin binding in in vitro assays. We sought to identify mutations in other genes that might be responsible for the loss of binding. We employed a map-based cloning approach using a series of backcrosses with 1,060 progeny to identify a resistance gene in the cotton pest Heliothis virescens that segregated independently from the cadherin mutation. We found an inactivating mutation of the ABC transporter ABCC2 that is genetically linked to Cry1Ac resistance and is correlated with loss of Cry1Ac binding to membrane vesicles. ABC proteins are integral membrane proteins with many functions, including export of toxic molecules from the cell, but have not been implicated in the mode of action of Bt toxins before. The reduction in toxin binding due to the inactivating mutation suggests that ABCC2 is involved in membrane integration of the toxin pore. Our findings suggest that ABC proteins may play a key role in the mode of action of Bt toxins and that ABC protein mutations can confer high levels of resistance that could threaten the continued utilization of Bt-expressing crops. However, such mutations may impose a physiological cost on resistant insects, by reducing export of other toxins such as plant secondary compounds from the cell. This weakness could be exploited to manage this mechanism of Bt resistance in the field.

  10. Expression pattern of the human ABC transporters in pluripotent embryonic stem cells and in their derivatives.

    Science.gov (United States)

    Erdei, Zsuzsa; Lőrincz, Réka; Szebényi, Kornélia; Péntek, Adrienn; Varga, Nóra; Likó, István; Várady, György; Szakács, Gergely; Orbán, Tamás I; Sarkadi, Balázs; Apáti, Agota

    2014-09-01

    ATP-binding cassette (ABC) transporters have key roles in various physiological functions as well as providing chemical defense and stress tolerance in human tissues. In this study, we have examined the expression pattern of all ABC proteins in pluripotent human embryonic stem cells (hESCs) and in their differentiated progenies. We paid special attention to the cellular expression and localization of multidrug transporter ABC proteins. Stem cell differentiation was carried out without chemical induction or cell sorting, and specialized cell types were separated mechanically. Cellular features regarding pluripotency and tissue identity, as well as ABC transporter expression were studied by flow cytomtery, immuno-microscopy, and qPCR-based low-density arrays. Pluripotent hESCs and differentiated cell types (cardiomyocytes, neuronal cells, and mesenchymal stem cells) were distinguished by morphology, immunostaining markers, and selected mRNA expression patterns. We found that the mRNA expression levels of the 48 human ABC proteins also clearly distinguished the pluripotent and the respective differentiated cell types. When multidrug and lipid transporter ABC protein expression was examined by using well characterized specific antibodies by flow cytometry and confocal microscopy, the protein expression data corresponded well to the mRNA expression results. Moreover, the cellular localization of these important human ABC transporter proteins could be established in the pluripotent and differentiated hESC derived samples. These studies provide valuable information regarding ABC protein expression in human stem cells and their differentiated offspring. The results may also help to obtain further information concerning the specialized cellular functions of selected ABC transporters. © 2014 Clinical Cytometry Society.

  11. ATP binding cassette (ABC) transporters: expression and clinical value in glioblastoma.

    Science.gov (United States)

    Dréan, Antonin; Rosenberg, Shai; Lejeune, François-Xavier; Goli, Larissa; Nadaradjane, Aravindan Arun; Guehennec, Jérémy; Schmitt, Charlotte; Verreault, Maïté; Bielle, Franck; Mokhtari, Karima; Sanson, Marc; Carpentier, Alexandre; Delattre, Jean-Yves; Idbaih, Ahmed

    2018-03-08

    ATP-binding cassette transporters (ABC transporters) regulate traffic of multiple compounds, including chemotherapeutic agents, through biological membranes. They are expressed by multiple cell types and have been implicated in the drug resistance of some cancer cells. Despite significant research in ABC transporters in the context of many diseases, little is known about their expression and clinical value in glioblastoma (GBM). We analyzed expression of 49 ABC transporters in both commercial and patient-derived GBM cell lines as well as from 51 human GBM tumor biopsies. Using The Cancer Genome Atlas (TCGA) cohort as a training dataset and our cohort as a validation dataset, we also investigated the prognostic value of these ABC transporters in newly diagnosed GBM patients, treated with the standard of care. In contrast to commercial GBM cell lines, GBM-patient derived cell lines (PDCL), grown as neurospheres in a serum-free medium, express ABC transporters similarly to parental tumors. Serum appeared to slightly increase resistance to temozolomide correlating with a tendency for an increased expression of ABCB1. Some differences were observed mainly due to expression of ABC transporters by microenvironmental cells. Together, our data suggest that the efficacy of chemotherapeutic agents may be misestimated in vitro if they are the targets of efflux pumps whose expression can be modulated by serum. Interestingly, several ABC transporters have prognostic value in the TCGA dataset. In our cohort of 51 GBM patients treated with radiation therapy with concurrent and adjuvant temozolomide, ABCA13 overexpression is associated with a decreased progression free survival in univariate (p ABC transporters is: (i) detected in GBM and microenvironmental cells and (ii) better reproduced in GBM-PDCL. ABCA13 expression is an independent prognostic factor in newly diagnosed GBM patients. Further prospective studies are warranted to investigate whether ABCA13 expression can be

  12. ATP-binding cassette (ABC transporters in normal and pathological lung

    Directory of Open Access Journals (Sweden)

    Timmer-Bosscha Hetty

    2005-06-01

    Full Text Available Abstract ATP-binding cassette (ABC transporters are a family of transmembrane proteins that can transport a wide variety of substrates across biological membranes in an energy-dependent manner. Many ABC transporters such as P-glycoprotein (P-gp, multidrug resistance-associated protein 1 (MRP1 and breast cancer resistance protein (BCRP are highly expressed in bronchial epithelium. This review aims to give new insights in the possible functions of ABC molecules in the lung in view of their expression in different cell types. Furthermore, their role in protection against noxious compounds, e.g. air pollutants and cigarette smoke components, will be discussed as well as the (malfunction in normal and pathological lung. Several pulmonary drugs are substrates for ABC transporters and therefore, the delivery of these drugs to the site of action may be highly dependent on the presence and activity of many ABC transporters in several cell types. Three ABC transporters are known to play an important role in lung functioning. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR gene can cause cystic fibrosis, and mutations in ABCA1 and ABCA3 are responsible for respectively Tangier disease and fatal surfactant deficiency. The role of altered function of ABC transporters in highly prevalent pulmonary diseases such as asthma or chronic obstructive pulmonary disease (COPD have hardly been investigated so far. We especially focused on polymorphisms, knock-out mice models and in vitro results of pulmonary research. Insight in the function of ABC transporters in the lung may open new ways to facilitate treatment of lung diseases.

  13. Investigation of the quaternary structure of an ABC transporter in living cells using spectrally resolved resonance energy transfer

    Science.gov (United States)

    Singh, Deo Raj

    Forster resonance energy transfer (FRET) has become an important tool to study proteins inside living cells. It has been used to explore membrane protein folding and dynamics, determine stoichiometry and geometry of protein complexes, and measure the distance between two molecules. In this dissertation, we use a method based on FRET and optical micro-spectroscopy (OptiMiS) technology, developed in our lab, to probe the structure of dynamic (as opposed to static) protein complexes in living cells. We use this method to determine the association stoichiometry and quaternary structure of an ABC transporter in living cells. Specifically, the transporter we investigate originates from the pathogen Pseudomonas aeruginosa, which is a Gram-negative bacterium with several virulence factors, lipopolysaccharides being one of them. This pathogen coexpresses two unique forms of lipopolysaccharides on its surface, the A- and B-bands. The A-band polysaccharides, synthesized in the cytoplasm, are translocated into the periplasm through an ATP-binding-cassette (ABC) transporter consisting of a transmembranar protein, Wzm, and a nucleotide-binding protein, Wzt. In P. aeruginosa, all of the biochemical studies of A-band LPS are concentrated on the stages of the synthesis and ligation of polysaccharides (PSs), leaving the export stage involving ABC transporter unexplored. The mode of PS export through ABC transporters is still unknown. This difficulty is due to the lack of information about sub-unit composition and structure of this bi-component ABC transporter. Using the FRET-OptiMiS combination method developed by our lab, we found that Wzt forms a rhombus-shaped homo-tetramer which becomes a square upon co-expression with Wzm, and that Wzm forms a square-shaped homo-tetramer both in the presence and absence of Wzt. Based on these results, we propose a structural model for the double-tetramer complex formed by the bi-component ABC transporter in living cells. An understanding of the

  14. The predicted ABC transporter AbcEDCBA is required for type IV secretion system expression and lysosomal evasion by Brucella ovis.

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    Teane M A Silva

    Full Text Available Brucella ovis is a major cause of reproductive failure in rams and it is one of the few well-described Brucella species that is not zoonotic. Previous work showed that a B. ovis mutant lacking a species-specific ABC transporterabcBA was attenuated in mice and was unable to survive in macrophages. The aim of this study was to evaluate the role of this ABC transporter during intracellular survival of B. ovis. In HeLa cells, B. ovis WT was able to survive and replicate at later time point (48 hpi, whereas an ΔabcBA mutant was attenuated at 24 hpi. The reduced survival of the ΔabcBA mutant was associated with a decreased ability to exclude the lysosomal marker LAMP1 from its vacuolar membrane, suggesting a failure to establish a replicative niche. The ΔabcBA mutant showed a reduced abundance of the Type IV secretion system (T4SS proteins VirB8 and VirB11 in both rich and acid media, when compared to WT B. ovis. However, mRNA levels of virB1, virB8, hutC, and vjbR were similar in both strains. These results support the notion that the ABC transporter encoded by abcEDCBA or its transported substrate acts at a post-transcriptional level to promote the optimal expression of the B. ovis T4SS within infected host cells.

  15. Whole-Transcriptome Survey of the Putative ATP-Binding Cassette (ABC) Transporter Family Genes in the Latex-Producing Laticifers of Hevea brasiliensis

    Science.gov (United States)

    Zhiyi, Nie; Guijuan, Kang; Yu, Li; Longjun, Dai; Rizhong, Zeng

    2015-01-01

    The ATP-binding cassette (ABC) proteins or transporters constitute a large protein family in plants and are involved in many different cellular functions and processes, including solute transportation, channel regulation and molecular switches, etc. Through transcriptome sequencing, a transcriptome-wide survey and expression analysis of the ABC protein genes were carried out using the laticiferous latex from Hevea brasiliensis (rubber tree). A total of 46 putative ABC family proteins were identified in the H. brasiliensis latex. These consisted of 12 ‘full-size’, 21 ‘half-size’ and 13 other putative ABC proteins, and all of them showed strong conservation with their Arabidopsis thaliana counterparts. This study indicated that all eight plant ABC protein paralog subfamilies were identified in the H. brasiliensis latex, of which ABCB, ABCG and ABCI were the most abundant. Real-time quantitative reverse transcription-polymerase chain reaction assays demonstrated that gene expression of several latex ABC proteins was regulated by ethylene, jasmonic acid or bark tapping (a wound stress) stimulation, and that HbABCB15, HbABCB19, HbABCD1 and HbABCG21 responded most significantly of all to the abiotic stresses. The identification and expression analysis of the latex ABC family proteins could facilitate further investigation into their physiological involvement in latex metabolism and rubber biosynthesis by H. brasiliensis. PMID:25615936

  16. The multidrug-resistant phenotype associated with overexpression of the new ABC half-transporter, MXR (ABCG2)

    DEFF Research Database (Denmark)

    Litman, Thomas; Brangi, M; Hudson, E

    2000-01-01

    Mechanisms of drug resistance other than P-glycoprotein are of increasing interest as the list of newly identified members of the ABC transport family has grown. We sought to characterize the phenotype of the newly discovered ABC transporter encoded by the mitoxantrone resistance gene, MXR, also...... that the ABC half-transporter, MXR, is a potent, new mechanism for conferring multiple drug resistance. Definition of its mechanism of transport and its role in clinical oncology is required....

  17. ABC transporters in Mycoplasma hyopneumoniae and Mycoplasma synoviae: insights into evolution and pathogenicity

    Directory of Open Access Journals (Sweden)

    Marisa Fabiana Nicolás

    2007-01-01

    Full Text Available ABC transporters represent one of the largest superfamilies of active membrane transport proteins (MTPs with a highly conserved ATPase domain that binds and hydrolyzes ATP, supplying energy for the uptake of a variety of nutrients and for the extrusion of drugs and metabolic wastes. The complete genomes of a non-pathogenic (J and pathogenic (7448 strain of Mycoplasma hyopneumoniae, as well as of a pathogenic (53 strain of Mycoplasma synoviae have been recently sequenced. A detailed study revealed a high percentage of CDSs encoding MTPs in M. hyopneumoniae strains J (13.4%, 7448 (13.8%, and in M. synoviae 53 (11.2%, and the ABC systems represented from 85.0 to 88.6% of those CDSs. Uptake systems are mainly involved in cell nutrition and some might be associated with virulence. Exporter systems include both drug and multidrug resistant systems (MDR, which may represent mechanisms of resistance to toxic molecules. No relation was found between the phylogeny of the ATPase domains and the lifestyle or pathogenicity of Mycoplasma, but several proteins, potentially useful as targets for the control of infections, were identified.

  18. Multi-Drug Resistance ABC Transporter Inhibition Enhances Murine Ventral Prostate Stem/Progenitor Cell Differentiation.

    Science.gov (United States)

    Samant, Mugdha D; Jackson, Courtney M; Felix, Carina L; Jones, Anthony J; Goodrich, David W; Foster, Barbara A; Huss, Wendy J

    2015-05-15

    Multi-drug resistance (MDR)-ATP binding cassette (ABC) transporters, ABCB1, ABCC1, and ABCG2 participate in the efflux of steroid hormones, estrogens, and androgens, which regulate prostate development and differentiation. The role of MDR-ABC efflux transporters in prostate epithelial proliferation and differentiation remains unclear. We hypothesized that MDR-ABC transporters regulate prostate differentiation and epithelium regeneration. Prostate epithelial differentiation was studied using histology, sphere formation assay, and prostate regeneration induced by cycles of repeated androgen withdrawal and replacement. Embryonic deletion of Abcg2 resulted in a decreased number of luminal cells in the prostate and increased sphere formation efficiency, indicating an imbalance in the prostate epithelial differentiation pattern. Decreased luminal cell number in the Abcg2 null prostate implies reduced differentiation. Enhanced sphere formation efficiency in Abcg2 null prostate cells implies activation of the stem/progenitor cells. Prostate regeneration was associated with profound activation of the stem/progenitor cells, indicating the role of Abcg2 in maintaining stem/progenitor cell pool. Since embryonic deletion of Abcg2 may result in compensation by other ABC transporters, pharmacological inhibition of MDR-ABC efflux was performed. Pharmacological inhibition of MDR-ABC efflux enhanced prostate epithelial differentiation in sphere culture and during prostate regeneration. In conclusion, Abcg2 deletion leads to activation of the stem/progenitor cells and enhances differentiating divisions; and pharmacological inhibition of MDR-ABC efflux leads to epithelial differentiation. Our study demonstrates for the first time that MDR-ABC efflux transporter inhibition results in enhanced prostate epithelial cell differentiation.

  19. Frequent down-regulation of ABC transporter genes in prostate cancer

    International Nuclear Information System (INIS)

    Demidenko, Rita; Razanauskas, Deividas; Daniunaite, Kristina; Lazutka, Juozas Rimantas; Jankevicius, Feliksas; Jarmalaite, Sonata

    2015-01-01

    ATP-binding cassette (ABC) transporters are transmembrane proteins responsible for the efflux of a wide variety of substrates, including steroid metabolites, through the cellular membranes. For better characterization of the role of ABC transporters in prostate cancer (PCa) development, the profile of ABC transporter gene expression was analyzed in PCa and noncancerous prostate tissues (NPT). TaqMan Low Density Array (TLDA) human ABC transporter plates were used for the gene expression profiling in 10 PCa and 6 NPT specimens. ABCB1 transcript level was evaluated in a larger set of PCa cases (N = 78) and NPT (N = 15) by real-time PCR, the same PCa cases were assessed for the gene promoter hypermethylation by methylation-specific PCR. Expression of eight ABC transporter genes (ABCA8, ABCB1, ABCC6, ABCC9, ABCC10, ABCD2, ABCG2, and ABCG4) was significantly down-regulated in PCa as compared to NPT, and only two genes (ABCC4 and ABCG1) were up-regulated. Down-regulation of ABC transporter genes was prevalent in the TMPRSS2-ERG-negative cases. A detailed analysis of ABCB1 expression confirmed TLDA results: a reduced level of the transcript was identified in PCa in comparison to NPT (p = 0.048). Moreover, the TMPRSS2-ERG-negative PCa cases showed significantly lower expression of ABCB1 in comparison to NPT (p = 0.003) or the fusion-positive tumors (p = 0.002). Promoter methylation of ABCB1 predominantly occurred in PCa and was rarely detected in NPT (p < 0.001). The study suggests frequent down-regulation of the ABC transporter genes in PCa, especially in the TMPRSS2-ERG-negative tumors. The online version of this article (doi:10.1186/s12885-015-1689-8) contains supplementary material, which is available to authorized users

  20. Identification of ABC transporter genes of Fusarium graminearum with roles in azole tolerance and/or virulence.

    Directory of Open Access Journals (Sweden)

    Ghada Abou Ammar

    Full Text Available Fusarium graminearum is a plant pathogen infecting several important cereals, resulting in substantial yield losses and mycotoxin contamination of the grain. Triazole fungicides are used to control diseases caused by this fungus on a worldwide scale. Our previous microarray study indicated that 15 ABC transporter genes were transcriptionally upregulated in response to tebuconazole treatment. Here, we deleted four ABC transporter genes in two genetic backgrounds of F. graminearum representing the DON (deoxynivalenol and the NIV (nivalenol trichothecene chemotypes. Deletion of FgABC3 and FgABC4 belonging to group I of ABC-G and to group V of ABC-C subfamilies of ABC transporters, respectively, considerably increased the sensitivity to the class I sterol biosynthesis inhibitors triazoles and fenarimol. Such effects were specific since they did not occur with any other fungicide class tested. Assessing the contribution of the four ABC transporters to virulence of F. graminearum revealed that, irrespective of their chemotypes, deletion mutants of FgABC1 (ABC-C subfamily group V and FgABC3 were impeded in virulence on wheat, barley and maize. Phylogenetic context and analyses of mycotoxin production suggests that FgABC3 may encode a transporter protecting the fungus from host-derived antifungal molecules. In contrast, FgABC1 may encode a transporter responsible for the secretion of fungal secondary metabolites alleviating defence of the host. Our results show that ABC transporters play important and diverse roles in both fungicide resistance and pathogenesis of F. graminearum.

  1. The AbcA Transporter of Staphylococcus aureus Affects Cell Autolysis

    Science.gov (United States)

    Schrader-Fischer, Gesine; Berger-Bächi, Brigitte

    2001-01-01

    Increased production of penicillin-binding protein PBP 4 is known to increase peptidoglycan cross-linking and contributes to methicillin resistance in Staphylococcus aureus. The pbp4 gene shares a 400-nucleotide intercistronic region with the divergently transcribed abcA gene, encoding an ATP-binding cassette transporter of unknown function. Our study revealed that methicillin stimulated abcA transcription but had no effects on pbp4 transcription. Analysis of abcA expression in mutants defective for global regulators showed that abcA is under the control of agr. Insertional inactivation of abcA by an erythromycin resistance determinant did not influence pbp4 transcription, nor did it alter resistance to methicillin and other cell wall-directed antibiotics. However, abcA mutants showed spontaneous partial lysis on plates containing subinhibitory concentrations of methicillin due to increased spontaneous autolysis. Since the autolytic zymograms of cell extracts were identical in mutants and parental strains, we postulate an indirect role of AbcA in control of autolytic activities and in protection of the cells against methicillin. PMID:11158733

  2. ABC transporters as multidrug resistance mechanisms and the development of chemosensitizers for their reversal

    Directory of Open Access Journals (Sweden)

    Choi Cheol-Hee

    2005-10-01

    Full Text Available Abstract One of the major problems related with anticancer chemotherapy is resistance against anticancer drugs. The ATP-binding cassette (ABC transporters are a family of transporter proteins that are responsible for drug resistance and a low bioavailability of drugs by pumping a variety of drugs out cells at the expense of ATP hydrolysis. One strategy for reversal of the resistance of tumor cells expressing ABC transporters is combined use of anticancer drugs with chemosensitizers. In this review, the physiological functions and structures of ABC transporters, and the development of chemosensitizers are described focusing on well-known proteins including P-glycoprotein, multidrug resistance associated protein, and breast cancer resistance protein.

  3. Genome-wide analysis of ATP-binding cassette (ABC) transporters in the sweetpotato whitefly, Bemisia tabaci.

    Science.gov (United States)

    Tian, Lixia; Song, Tianxue; He, Rongjun; Zeng, Yang; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Zhou, Xuguo; Zhang, Youjun

    2017-04-26

    ABC transporter superfamily is one of the largest and ubiquitous groups of proteins. Because of their role in detoxification, insect ABC transporters have gained more attention in recent years. In this study, we annotated ABC transporters from a newly sequenced sweetpotato whitefly genome. Bemisia tabaci Q biotype is an emerging global invasive species that has caused extensive damages to field crops as well as ornamental plants. A total of 55 ABC transporters containing all eight described subfamilies (A to H) were identified in the B. tabaci Q genome, including 8 ABCAs, 3 ABCBs, 6 ABCCs, 2 ABCDs, 1 ABCE, 3 ABCFs, 23 ABCGs and 9 ABCHs. In comparison to other species, subfamilies G and H in both phloem- and blood-sucking arthropods are expanded. The temporal expression profiles of these 55 ABC transporters throughout B. tabaci developmental stages and their responses to imidacloprid, a neonicotinoid insecticide, were investigated using RNA-seq analysis. Furthermore, the mRNA expression of 24 ABC transporters (44% of the total) representing all eight subfamilies was confirmed by the quantitative real-time PCR (RT-qPCR). Furthermore, mRNA expression levels estimated by RT-qPCR and RNA-seq analyses were significantly correlated (r = 0.684, p ABC transporters in B. tabaci. The identification of these ABC transporters, their temporal expression profiles during B. tabaci development, and their response to a neonicotinoid insecticide lay the foundation for functional genomic understanding of their contribution to the invasiveness of B. tabaci.

  4. Plant ABC transporters enable many unique aspects of a terrestrial plant's lifestyle

    DEFF Research Database (Denmark)

    Hwang, Jae-Ung; Song, Won-Yong; Hong, Daewoong

    2016-01-01

    Terrestrial plants have two to four times more ATP-binding cassette (ABC) transporter genes than other organisms, including their ancestral microalgae. Recent studies found that plants harboring mutations in these transporters exhibit dramatic phenotypes, many of which are related to developmental...

  5. Transcriptome-based identification of ABC transporters in the western tarnished plant bug lygus hesperus

    Science.gov (United States)

    ATP-binding cassette (ABC) transporters are a large superfamily of proteins that mediate diverse physiological functions by coupling ATP hydrolysis with substrate transport across lipid membranes. In insects, these proteins play roles in metabolism, development, eye pigmentation, and xenobiotic cle...

  6. Functional Diversity of Tandem Substrate-Binding Domains in ABC Transporters from Pathogenic Bacteria

    NARCIS (Netherlands)

    Fulyani, Faizah; Schuurman-Wolters, Gea K.; Vujicic - Zagar, Andreja; Guskov, Albert; Slotboom, Dirk-Jan; Poolman, Bert

    2013-01-01

    The ATP-binding cassette (ABC) transporter GInPQ is an essential uptake system for amino acids in gram-positive pathogens and related nonpathogenic bacteria. The transporter has tandem substrate-binding domains (SBDs) fused to each transmembrane domain, giving rise to four SBDs per functional

  7. The human ABC transporter pseudogene family: Evidence for transcription and gene-pseudogene interference.

    Science.gov (United States)

    Piehler, Armin P; Hellum, Marit; Wenzel, Jürgen J; Kaminski, Ellen; Haug, Kari Bente Foss; Kierulf, Peter; Kaminski, Wolfgang E

    2008-04-11

    Pseudogenes are an integral component of the human genome. Little attention, however, has so far been paid to the phenomenon that some pseudogenes are transcriptionally active. Recently, we demonstrated that the human ortholog of the rodent testis-specific ATP-binding cassette (ABC) transporter Abca17 is a ubiquitously transcribed pseudogene (ABCA17P). The aim of the present study was to establish a complete inventory of all ABC transporter pseudogenes in the human genome and to identify transcriptionally active ABC transporter pseudogenes. Moreover, we tested the hypothesis that a regulatory interdependency exists between ABC transporter pseudogenes and their parental protein coding equivalents. Systematic bioinformatic analysis revealed the existence of 22 ABC transporter pseudogenes within the human genome. We identified two clusters on chromosomes 15 and 16, respectively, which harbor almost half of all pseudogenes (n = 10). Available information from EST and mRNA databases and RT-PCR expression profiling indicate that a large portion of the ABC transporter pseudogenes (45%, n = 10) are transcriptionally active and some of them are expressed as alternative splice variants. We demonstrate that both pseudogenes of the pseudoxanthoma elasticum gene ABCC6, ABCC6P1 and ABCC6P2, are transcribed. ABCC6P1 and ABCC6 possess near-identical promoter sequences and their tissue-specific expression profiles are strikingly similar raising the possibility that they form a gene-pseudogene dual transcription unit. Intriguingly, targeted knockdown of the transcribed pseudogene ABCC6P1 resulted in a significant reduction of ABCC6 mRNA expression levels. The human genome contains a surprisingly small number of ABC transporter pseudogenes relative to other known gene families. They are unevenly distributed across the chromosomes. Importantly, a significant portion of the ABC transporter pseudogenes is transcriptionally active. The downregulation of ABCC6 mRNA levels by targeted

  8. The human ABC transporter pseudogene family: Evidence for transcription and gene-pseudogene interference

    Directory of Open Access Journals (Sweden)

    Haug Kari

    2008-04-01

    Full Text Available Abstract Background Pseudogenes are an integral component of the human genome. Little attention, however, has so far been paid to the phenomenon that some pseudogenes are transcriptionally active. Recently, we demonstrated that the human ortholog of the rodent testis-specific ATP-binding cassette (ABC transporter Abca17 is a ubiquitously transcribed pseudogene (ABCA17P. The aim of the present study was to establish a complete inventory of all ABC transporter pseudogenes in the human genome and to identify transcriptionally active ABC transporter pseudogenes. Moreover, we tested the hypothesis that a regulatory interdependency exists between ABC transporter pseudogenes and their parental protein coding equivalents. Results Systematic bioinformatic analysis revealed the existence of 22 ABC transporter pseudogenes within the human genome. We identified two clusters on chromosomes 15 and 16, respectively, which harbor almost half of all pseudogenes (n = 10. Available information from EST and mRNA databases and RT-PCR expression profiling indicate that a large portion of the ABC transporter pseudogenes (45%, n = 10 are transcriptionally active and some of them are expressed as alternative splice variants. We demonstrate that both pseudogenes of the pseudoxanthoma elasticum gene ABCC6, ABCC6P1 and ABCC6P2, are transcribed. ABCC6P1 and ABCC6 possess near-identical promoter sequences and their tissue-specific expression profiles are strikingly similar raising the possibility that they form a gene-pseudogene dual transcription unit. Intriguingly, targeted knockdown of the transcribed pseudogene ABCC6P1 resulted in a significant reduction of ABCC6 mRNA expression levels. Conclusion The human genome contains a surprisingly small number of ABC transporter pseudogenes relative to other known gene families. They are unevenly distributed across the chromosomes. Importantly, a significant portion of the ABC transporter pseudogenes is transcriptionally active

  9. The Role of Eukaryotic and Prokaryotic ABC Transporter Family in Failure of Chemotherapy.

    Science.gov (United States)

    El-Awady, Raafat; Saleh, Ekram; Hashim, Amna; Soliman, Nehal; Dallah, Alaa; Elrasheed, Azza; Elakraa, Ghada

    2016-01-01

    Over the years chemotherapy failure has been a vital research topic as researchers have been striving to discover reasons behind it. The extensive studies carried out on chemotherapeutic agents confirm that resistance to chemotherapy is a major reason for treatment failure. "Resistance to chemotherapy," however, is a comprehensive phrase that refers to a variety of different mechanisms in which ATP-binding cassette (ABC) mediated efflux dominates. The ABC is one of the largest gene superfamily of transporters among both eukaryotes and prokaryotes; it represents a variety of genes that code for proteins, which perform countless functions, including drug efflux - a natural process that protects cells from foreign chemicals. Up to date, chemotherapy failure due to ABC drug efflux is an active research topic that continuously provides further evidence on multiple drug resistance (MDR), aiding scientists in tackling and overcoming this issue. This review focuses on drug resistance by ABC efflux transporters in human, viral, parasitic, fungal and bacterial cells and highlights the importance of the MDR permeability glycoprotein being the mutual ABC transporter among all studied organisms. Current developments and future directions to overcome this problem are also discussed.

  10. The role of ABCG-type ABC transporters in phytohormone transport.

    Science.gov (United States)

    Borghi, Lorenzo; Kang, Joohyun; Ko, Donghwi; Lee, Youngsook; Martinoia, Enrico

    2015-10-01

    Plant hormones (phytohormones) integrate endogenous and exogenous signals thus synchronizing plant growth with environmental and developmental changes. Similar to animals, phytohormones have distinct source and target tissues, hence controlled transport and focused targeting are required for their functions. Many evidences accumulated in the last years about the regulation of long-distance and directional transport of phytohormones. ATP-binding cassette (ABC) transporters turned out to play major roles in routing phytohormones not only in the plant body but also towards the outer environment. The ABCG-type proteins ABCG25 and ABCG40 are high affinity abscisic acid (ABA) transporters. ABCG14 is highly co-expressed with cytokinin biosynthesis and is the major root-to-shoot cytokinin transporter. Pleiotropic drug resistance1 (PDR1) from Petunia hybrida transports strigolactones (SLs) from the root tip to the plant shoot but also outside to the rhizosphere, where SLs are the main attractants to mycorrhizal fungi. Last but not least, ABCG36 and ABCG37 possibly play a dual role in coumarine and IBA transport. © 2015 Authors.

  11. Inhibition of the Human ABC Efflux Transporters P-gp and ...

    Science.gov (United States)

    High body burdens of polybrominated diphenyl ethers (PBDEs) in infants and young children have led to increased concern over their potential impact on human development. PBDE exposure can alter the expression of genes involved in thyroid homeostasis, including those of ATP-binding cassette (ABC) transporters, which mediate cellular xenobiotic efflux. However, little information exists on how PBDEs interact with ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). The purpose of this study was to evaluate the interactions of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and its hydroxylated metabolite 6-OH-BDE-47 with P-gp and BCRP, using human MDR1- and BCRP-expressing membrane vesicles and stably transfected NIH-3T3-MDR1 and MDCK-BCRP cells. In P-gp membranes, BDE-47 did not affect P-gp activity; however, 6-OH-BDE-47 inhibited P-gp activity at low µM concentrations (IC50 = 11.7 µM). In BCRP membranes, BDE-47 inhibited BCRP activity; however, 6-OH-BDE-47 was a stronger inhibitor [IC50 = 45.9 µM (BDE-47) vs. IC50 = 9.4 µM (6-OH-BDE-47)]. Intracellular concentrations of known P-gp and BCRP substrates [(3H)-paclitaxel and (3H)-prazosin, respectively] were significantly higher (indicating less efflux) in NIH-3T3-MDR1 and MDCK-BCRP cells in the presence of 6-OH-BDE-47, but not BDE-47. Collectively, our results indicate that the BDE-47 metabolite 6-OH-BDE-47 is an inhibitor of both P-gp and BCRP efflux activity.

  12. Structural basis for antibacterial peptide self-immunity by the bacterial ABC transporter McjD.

    Science.gov (United States)

    Bountra, Kiran; Hagelueken, Gregor; Choudhury, Hassanul G; Corradi, Valentina; El Omari, Kamel; Wagner, Armin; Mathavan, Indran; Zirah, Séverine; Yuan Wahlgren, Weixiao; Tieleman, D Peter; Schiemann, Olav; Rebuffat, Sylvie; Beis, Konstantinos

    2017-10-16

    Certain pathogenic bacteria produce and release toxic peptides to ensure either nutrient availability or evasion from the immune system. These peptides are also toxic to the producing bacteria that utilize dedicated ABC transporters to provide self-immunity. The ABC transporter McjD exports the antibacterial peptide MccJ25 in Escherichia coli Our previously determined McjD structure provided some mechanistic insights into antibacterial peptide efflux. In this study, we have determined its structure in a novel conformation, apo inward-occluded and a new nucleotide-bound state, high-energy outward-occluded intermediate state, with a defined ligand binding cavity. Predictive cysteine cross-linking in E. coli membranes and PELDOR measurements along the transport cycle indicate that McjD does not undergo major conformational changes as previously proposed for multi-drug ABC exporters. Combined with transport assays and molecular dynamics simulations, we propose a novel mechanism for toxic peptide ABC exporters that only requires the transient opening of the cavity for release of the peptide. We propose that shielding of the cavity ensures that the transporter is available to export the newly synthesized peptides, preventing toxic-level build-up. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  13. A wheat ABC transporter contributes to both grain formation and mycotoxin tolerance

    Science.gov (United States)

    Deoxynivalenol (DON) is a mycotoxin produced by Fusarium fungi which acts as a disease virulence factor, aiding fungal pathogenesis of cereals spikelets and spread of the economically important Fusarium head blight (FHB) disease. Previously, a fragment of a wheat ABC transporter gene was shown to be...

  14. Genetic variation in ABC transporter A1 contributes to HDL cholesterol in the general population

    DEFF Research Database (Denmark)

    Frikke-Schmidt, Ruth; Nordestgaard, Børge G; Jensen, Gorm B

    2004-01-01

    Homozygosity for mutations in ABC transporter A1 (ABCA1) causes Tangier disease, a rare HDL-deficiency syndrome. Whether heterozygosity for genetic variation in ABCA1 also contributes to HDL cholesterol (HDL-C) levels in the general population is presently unclear. We determined whether mutations...

  15. Gangliosides do not affect ABC transporter function in human neuroblastoma cells

    NARCIS (Netherlands)

    Dijkhuis, Anne-Jan; Klappe, Karin; Kamps, Willem; Sietsma, Hannie; Kok, Jan Willem

    Previous studies have indicated a role for glucosylceramide synthase (GCS) in multidrug resistance (MDR), either related to turnover of ceramide (Cer) or generation of gangliosides, which modulate apoptosis and/or the activity of ABC transporters. This study challenges the hypothesis that

  16. Influence of detergents on the activity of the ABC transporter LmrA

    NARCIS (Netherlands)

    Infed, Nacera; Hanekop, Nils; Driessen, Arnold J. M.; Smits, Sander H. J.; Schmitt, Lutz

    The ABC transporter LmrA from Lactococcus lactis has been intensively studied and a role in multidrug resistance was proposed. Here, we performed a comprehensive detergent screen to analyze the impact of detergents for a successful solubilization, purification and retention of functional properties

  17. Transmembrane Domain Single-Nucleotide Polymorphisms Impair Expression and Transport Activity of ABC Transporter ABCG2.

    Science.gov (United States)

    Sjöstedt, Noora; van den Heuvel, Jeroen J M W; Koenderink, Jan B; Kidron, Heidi

    2017-08-01

    To study the function and expression of nine naturally occurring single-nucleotide polymorphisms (G406R, F431L, S441N, P480L, F489L, M515R, L525R, A528T and T542A) that are predicted to reside in the transmembrane regions of the ABC transporter ABCG2. The transport activity of the variants was tested in inside-out membrane vesicles from Sf9 insect and human derived HEK293 cells overexpressing ABCG2. Lucifer Yellow and estrone sulfate were used as probe substrates of activity. The expression levels and cellular localization of the variants was compared to the wild-type ABCG2 by western blotting and immunofluorescence microscopy. All studied variants of ABCG2 displayed markedly decreased transport in both Sf9-ABCG2 and HEK293-ABCG2 vesicles. Impaired transport could be explained for some variants by altered expression levels and cellular localization. Moreover, the destructive effect on transport activity of variants G406R, P480L, M515R and T542A is, to our knowledge, reported for the first time. These results indicate that the transmembrane region of ABCG2 is sensitive to amino acid substitution and that patients harboring these ABCG2 variant forms could suffer from unexpected pharmacokinetic events of ABCG2 substrate drugs or have an increased risk for diseases such as gout where ABCG2 is implicated.

  18. Congruence ABC implies ABC

    OpenAIRE

    Ellenberg, Jordan S.

    2000-01-01

    The ABC conjecture of Masser and Oesterle' states that if (a,b,c) are coprime integers with a + b + c = 0, then sup(|a|,|b|,|c|) 0. Oesterle' has observed that if the ABC conjecture holds for all (a,b,c) with 16 | abc, then the full ABC conjecture holds. We extend that result to show that, for every integer N, the "congruence ABC conjecture" that ABC holds for all (a,b,c) with N|abc implies the full ABC conjecture.

  19. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    Science.gov (United States)

    Bhattacharjee, Sourav; van Opstal, Edward J.; Alink, Gerrit M.; Marcelis, Antonius T. M.; Zuilhof, Han; Rietjens, Ivonne M. C. M.

    2013-06-01

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size 45 nm) and polystyrene nanoparticles (PSNPs/size 50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

  20. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Sourav, E-mail: sourav.bhattacharjee@wur.nl [Wageningen University, Laboratory of Organic Chemistry (Netherlands); Opstal, Edward J. van; Alink, Gerrit M. [Wageningen University, Division of Toxicology (Netherlands); Marcelis, Antonius T. M.; Zuilhof, Han [Wageningen University, Laboratory of Organic Chemistry (Netherlands); Rietjens, Ivonne M. C. M. [Wageningen University, Division of Toxicology (Netherlands)

    2013-06-15

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size {approx}45 nm) and polystyrene nanoparticles (PSNPs/size {approx}50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

  1. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    International Nuclear Information System (INIS)

    Bhattacharjee, Sourav; Opstal, Edward J. van; Alink, Gerrit M.; Marcelis, Antonius T. M.; Zuilhof, Han; Rietjens, Ivonne M. C. M.

    2013-01-01

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size ∼45 nm) and polystyrene nanoparticles (PSNPs/size ∼50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

  2. ATP-binding cassette (ABC) transporter expression and localization in sea urchin development.

    Science.gov (United States)

    Shipp, Lauren E; Hamdoun, Amro

    2012-06-01

    ATP-binding cassette (ABC) transporters are membrane proteins that regulate intracellular concentrations of myriad compounds and ions. There are >100 ABC transporter predictions in the Strongylocentrotus purpuratus genome, including 40 annotated ABCB, ABCC, and ABCG "multidrug efflux" transporters. Despite the importance of multidrug transporters for protection and signaling, their expression patterns have not been characterized in deuterostome embryos. Sea urchin embryos expressed 20 ABCB, ABCC, and ABCG transporter genes in the first 58 hr of development, from unfertilized egg to early prism. We quantified transcripts of ABCB1a, ABCB4a, ABCC1, ABCC5a, ABCC9a, and ABCG2b, and found that ABCB1a mRNA was 10-100 times more abundant than other transporter mRNAs. In situ hybridization showed ABCB1a was expressed ubiquitously in embryos, while ABCC5a was restricted to secondary mesenchyme cells and their precursors. Fluorescent protein fusions showed localization of ABCB1a on apical cell surfaces, and ABCC5a on basolateral surfaces. Embryos use many ABC transporters with predicted functions in cell signaling, lysosomal and mitochondrial homeostasis, potassium channel regulation, pigmentation, and xenobiotic efflux. Detailed characterization of ABCB1a and ABCC5a revealed that they have different temporal and spatial gene expression profiles and protein localization patterns that correlate to their predicted functions in protection and development, respectively. Copyright © 2012 Wiley Periodicals, Inc.

  3. Putative ABC transporter responsible for acetic acid resistance in Acetobacter aceti.

    Science.gov (United States)

    Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

    2006-01-01

    Two-dimensional gel electrophoretic analysis of the membrane fraction of Acetobacter aceti revealed the presence of several proteins that were produced in response to acetic acid. A 60-kDa protein, named AatA, which was mostly induced by acetic acid, was prepared; aatA was cloned on the basis of its NH2-terminal amino acid sequence. AatA, consisting of 591 amino acids and containing ATP-binding cassette (ABC) sequences and ABC signature sequences, belonged to the ABC transporter superfamily. The aatA mutation with an insertion of the neomycin resistance gene within the aatA coding region showed reduced resistance to acetic acid, formic acid, propionic acid, and lactic acid, whereas the aatA mutation exerted no effects on resistance to various drugs, growth at low pH (adjusted with HCl), assimilation of acetic acid, or resistance to citric acid. Introduction of plasmid pABC101 containing aatA under the control of the Escherichia coli lac promoter into the aatA mutant restored the defect in acetic acid resistance. In addition, pABC101 conferred acetic acid resistance on E. coli. These findings showed that AatA was a putative ABC transporter conferring acetic acid resistance on the host cell. Southern blot analysis and subsequent nucleotide sequencing predicted the presence of aatA orthologues in a variety of acetic acid bacteria belonging to the genera Acetobacter and Gluconacetobacter. The fermentation with A. aceti containing aatA on a multicopy plasmid resulted in an increase in the final yield of acetic acid.

  4. The ABC transporter ABC40 encodes a phenylacetic acid export system in Penicillium chrysogenum

    NARCIS (Netherlands)

    Weber, Stefan S.; Kovalchuk, Andriy; Bovenberg, Roe A. L.; Driessen, Arnold J. M.

    2012-01-01

    The filamentous fungus Penicillium chrysogenum is used for the industrial production of beta-lactam antibiotics. The pathway for beta-lactam biosynthesis has been resolved and involves the enzyme phenylacetic acid CoA ligase that is responsible for the CoA activation of the side chain precursor

  5. The mitochondrial transporter ABC-me (ABCB10), a downstream target of GATA-1, is essential for erythropoiesis in vivo

    Science.gov (United States)

    Hyde, B B; Liesa, M; Elorza, A A; Qiu, W; Haigh, S E; Richey, L; Mikkola, H K; Schlaeger, T M; Shirihai, O S

    2012-01-01

    The mitochondrial transporter ATP binding cassette mitochondrial erythroid (ABC-me/ABCB10) is highly induced during erythroid differentiation by GATA-1 and its overexpression increases hemoglobin production rates in vitro. However, the role of ABC-me in erythropoiesis in vivo is unknown. Here we report for the first time that erythrocyte development in mice requires ABC-me. ABC-me−/− mice die at day 12.5 of gestation, showing nearly complete eradication of primitive erythropoiesis and lack of hemoglobinized cells at day 10.5. ABC-me−/− erythroid cells fail to differentiate because they exhibit a marked increase in apoptosis, both in vivo and ex vivo. Erythroid precursors are particularly sensitive to oxidative stress and ABC-me in the heart and its yeast ortholog multidrug resistance-like 1 have been shown to protect against oxidative stress. Thus, we hypothesized that increased apoptosis in ABC-me−/− erythroid precursors was caused by oxidative stress. Within this context, ABC-me deletion causes an increase in mitochondrial superoxide production and protein carbonylation in erythroid precursors. Furthermore, treatment of ABC-me−/− erythroid progenitors with the mitochondrial antioxidant MnTBAP (superoxide dismutase 2 mimetic) supports survival, ex vivo differentiation and increased hemoglobin production. Altogether, our findings demonstrate that ABC-me is essential for erythropoiesis in vivo. PMID:22240895

  6. Arbuscular mycorrhiza affects nickel translocation and expression of ABC transporter and metallothionein genes in Festuca arundinacea.

    Science.gov (United States)

    Shabani, Leila; Sabzalian, Mohammad R; Mostafavi pour, Sodabeh

    2016-01-01

    Mycorrhizal fungi are key microorganisms for enhancing phytoremediation of soils contaminated with heavy metals. In this study, the effects of the arbuscular mycorrhizal fungus (AMF) Funneliformis mosseae (=Glomus mosseae) on physiological and molecular mechanisms involved in the nickel (Ni) tolerance of tall fescue (Festuca arundinacea = Schedonorus arundinaceus) were investigated. Nickel addition had a pronounced negative effect on tall fescue growth and photosynthetic pigment contents, as well as on AMF colonization. Phosphorus content increased markedly in mycorrhizal plants (M) compared to non-inoculated (NM) ones. However, no significant difference was observed in root carbohydrate content between AMF-inoculated and non-inoculated plants. For both M and NM plants, Ni concentrations in shoots and roots increased according to the addition of the metal into soil, but inoculation with F. mosseae led to significantly lower Ni translocation from roots to the aboveground parts compared to non-inoculated plants. ABC transporter and metallothionein transcripts accumulated to considerably higher levels in tall fescue plants colonized by F. mosseae than in the corresponding non-mycorrhizal plants. These results highlight the importance of mycorrhizal colonization in alleviating Ni-induced stress by reducing Ni transport from roots to shoots of tall fescue plants.

  7. Functional analysis of ABC transporter genes from Botrytis cinerea identifies BcatrB as a transporter of eugenol

    NARCIS (Netherlands)

    Schoonbeek, H.; Nistelrooy, van J.G.M.; Waard, de M.A.

    2003-01-01

    The role of multiple ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporter genes from the plant pathogenic fungus Botrytis cinerea in protection against natural fungitoxic compounds was studied by expression analysis and phenotyping of gene-replacement mutants. The

  8. Role of ABC transporters in veterinary medicine: pharmaco-toxicological implications.

    Science.gov (United States)

    Virkel, Guillermo; Ballent, Mariana; Lanusse, Carlos; Lifschitz, Adrian

    2018-01-31

    Unlike physicians, veterinary practitioners must deal with a number of animal species with crucial differences in anatomy, physiology and metabolism. Accordingly, the pharmacokinetic behaviour, the clinical efficacy and the adverse or toxic effects of drugs may differ across domestic animals. Moreover, the use of drugs in food-producing species may impose a risk for humans due to the generation of chemical residues in edible products, a major concern for public health and consumer's safety. As is clearly known in human beings, the ATP binding cassette (ABC) of transport proteins may influence the bioavailability and elimination of numerous drugs and other xenobiotics in domestic animals as well. A number of drugs, currently available in the veterinary market, are substrates of one or more transporters. Therefore, significant drug-drug interactions among ABC substrates may have unpredictable pharmaco-toxicological consequences in different species of veterinary interest. In this context, different investigations revealed the major relevance of P-gp and other transport proteins, like breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRPs), in both companion and livestock animals. Undoubtedly, the discovery of the ABC transporters and the deep understanding of their physiological role in the different species introduced a new paradigm into the veterinary pharmacology. This review focus on the expression and function of the major transport proteins expressed in species of veterinary interest, and their impact in drug disposition, efficacy and toxicity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. ABC transporters and xenobiotic defense systems in early life stages of rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Kropf, Christian; Segner, Helmut; Fent, Karl

    2016-01-01

    Embryos of oviparous fish, in contrast to (ovo) viviparous species, develop in the aquatic environment, and therefore need solute transport systems at their body surfaces for maintaining internal homeostasis and defending against potentially harmful substances. We hypothesized that solute transporters undergo changes in tissue distribution from the embryo to the larval stage. We therefore studied the mRNA profiles of eight ABC transporters (abcb1a, abcb1b, abcc1, abcc2, abcc3, abcc4, abcc5, abcg2) and three solute carriers (oatp1d, putative oatp2 putative, mate1) in different body regions (head, yolk sac epithelium, abdominal viscera, skin/muscles) of developing rainbow trout. Additionally, we investigated mRNA levels of phase I (cyp1a, cyp3a) and phase II (gstp, putative ugt1, putative ugt2) biotransformation enzymes. The study covered the developmental period from the eleuthero-embryo stage to the first-feeding larval stage (1-20days post-hatch, dph). At 1dph, transcripts of abcc2, abcc4, abcg2, cyp3a, gstp, putative mate1, and putative oatp2 occurred primarily in the yolk sac epithelium, whereas at later stages expression of these genes was predominantly observed in the abdominal viscera. The functional activity of ABC transporters in fish early life stages was assessed by rhodamine B accumulation assays. Finally, we investigated the potential impact of xenobiotics (clotrimazole, clofibric acid) on the ABC and biotransformation systems of trout early life stages. While clofibric acid had no effect, clotrimazole lead to an increased rhodamine B accumulation. The results provide evidence that the transition from the eleuthero-embryo to the larval stage is accompanied by a major alteration in tissue expression of ABC transporters. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Discovery of an auto-regulation mechanism for the maltose ABC transporter MalFGK2.

    Directory of Open Access Journals (Sweden)

    Huan Bao

    Full Text Available The maltose transporter MalFGK(2, together with the substrate-binding protein MalE, is one of the best-characterized ABC transporters. In the conventional model, MalE captures maltose in the periplasm and delivers the sugar to the transporter. Here, using nanodiscs and proteoliposomes, we instead find that MalE is bound with high-affinity to MalFGK2 to facilitate the acquisition of the sugar. When the maltose concentration exceeds the transport capacity, MalE captures maltose and dissociates from the transporter. This mechanism explains why the transport rate is high when MalE has low affinity for maltose, and low when MalE has high affinity for maltose. Transporter-bound MalE facilitates the acquisition of the sugar at low concentrations, but also captures and dissociates from the transporter past a threshold maltose concentration. In vivo, this maltose-forced dissociation limits the rate of transport. Given the conservation of the substrate-binding proteins, this mode of allosteric regulation may be universal to ABC importers.

  11. Multidrug ABC transporter Cdr1 of Candida albicans harbors specific and overlapping binding sites for human steroid hormones transport.

    Science.gov (United States)

    Baghel, Pratima; Rawal, Manpreet Kaur; Khan, Mohammad Firoz; Sen, Sobhan; Siddiqui, Mohammed Haris; Chaptal, Vincent; Falson, Pierre; Prasad, Rajendra

    2017-10-01

    The present study examines the kinetics of steroids efflux mediated by the Candida drug resistance protein 1 (Cdr1p) and evaluates their interaction with the protein. We exploited our in-house mutant library for targeting the 252 residues forming the twelve transmembrane helices (TMHs) of Cdr1p. The screening revealed 65 and 58 residues critical for β-estradiol and corticosterone transport, respectively. Notably, up to 83% critical residues for corticosterone face the lipid interface compared to 54% for β-estradiol. Molecular docking identified a possible peripheral corticosterone-binding site made of 8/14 critical/non-critical residues between TMHs 3, 4 and 6. β-estradiol transport was severely hampered by alanine replacements of Cdr1p core residues involving TMHs 2, 5 and 8, in a binding site made of 10/14 critical residues mainly shared with rhodamine 6G with which it competes. By contrast, TMH11 was poorly impacted, although being part of the core domain. Finally, we observed the presence of several contiguous stretches of 3-5 critical residues in TMHs 2, 5 and 10 that points to a rotation motion of these helices during the substrate transport cycle. The selective structural arrangement of the steroid-binding pockets in the core region and at the lipid-TMD interface, which was never reported before, together with the possible rotation of some TMHs may be the structural basis of the drug-transport mechanism achieved by these type II ABC transporters. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Brain barriers and functional interfaces with sequential appearance of ABC efflux transporters during human development

    DEFF Research Database (Denmark)

    Møllgård, Kjeld; Dziegielewska, Katarzyna M.; Holst, Camilla B.

    2017-01-01

    Adult brain is protected from entry of drugs and toxins by specific mechanisms such as ABC (ATP-binding Cassette) efflux transporters. Little is known when these appear in human brain during development. Cellular distribution of three main ABC transporters (ABCC1, ABCG2, ABCB1) was determined...... at blood-brain barriers and interfaces in human embryos and fetuses in first half of gestation. Antibodies against claudin-5 and-11 and antibodies to α-fetoprotein were used to describe morphological and functional aspects of brain barriers. First exchange interfaces to be established, probably at 4......-5 weeks post conception, are between brain and embryonic cerebrospinal fluid (eCSF) and between outer surface of brain anlage and primary meninx. They already exclude α-fetoprotein and are immunopositive for both claudins, ABCC1 and ABCG2. ABCB1 is detectable within a week of blood vessels first...

  13. ABC Transporter for Corrinoids in Halobacterium sp. Strain NRC-1†

    OpenAIRE

    Woodson, Jesse D.; Reynolds, April A.; Escalante-Semerena, Jorge C.

    2005-01-01

    We report evidence for the existence of a putative ABC transporter for corrinoid utilization in the extremely halophilic archaeon Halobacterium sp. strain NRC-1. Results from genetic and nutritional analyses of Halobacterium showed that mutants with lesions in open reading frames (ORFs) Vng1370G, Vng1371Gm, and Vng1369G required a 105-fold higher concentration of cobalamin for growth than the wild-type or parent strain. The data support the conclusion that these ORFs encode orthologs of the b...

  14. How to move an amphipathic molecule across a lipid bilayer: different mechanisms for different ABC transporters?

    Science.gov (United States)

    Theodoulou, Frederica L; Carrier, David J; Schaedler, Theresia A; Baldwin, Stephen A; Baker, Alison

    2016-06-15

    Import of β-oxidation substrates into peroxisomes is mediated by ATP binding cassette (ABC) transporters belonging to subfamily D. In order to enter the β-oxidation pathway, fatty acids are activated by conversion to fatty acyl-CoA esters, a reaction which is catalysed by acyl-CoA synthetases (ACSs). Here, we present evidence for an unusual transport mechanism, in which fatty acyl-CoA substrates are accepted by ABC subclass D protein (ABCD) transporters, cleaved by the transporters during transit across the lipid bilayer to release CoA, and ultimately re-esterified in the peroxisome lumen by ACSs which interact with the transporter. We propose that this solves the biophysical problem of moving an amphipathic molecule across the peroxisomal membrane, since the intrinsic thioesterase activity of the transporter permits separate membrane translocation pathways for the hydrophobic fatty acid moiety and the polar CoA moiety. The cleavage/re-esterification mechanism also has the potential to control entry of disparate substrates into the β-oxidation pathway when coupled with distinct peroxisomal ACSs. A different solution to the movement of amphipathic molecules across a lipid bilayer is deployed by the bacterial lipid-linked oligosaccharide (LLO) flippase, PglK, in which the hydrophilic head group and the hydrophobic polyprenyl tail of the substrate are proposed to have distinct translocation pathways but are not chemically separated during transport. We discuss a speculative alternating access model for ABCD proteins based on the mammalian ABC transporter associated with antigen processing (TAP) and compare it to the novel mechanism suggested by the recent PglK crystal structures and biochemical data. © 2016 The Author(s).

  15. Alzheimer's and ABC transporters--new opportunities for diagnostics and treatment.

    Science.gov (United States)

    Pahnke, Jens; Langer, Oliver; Krohn, Markus

    2014-12-01

    Much has been said about the increasing number of demented patients and the main risk factor 'age'. Frustratingly, we do not know the precise pattern and all modulating factors that provoke the pathologic changes in the brains of affected elderly. We have to diagnose early to be able to stop the progression of diseases that irreversibly destroy brain substance. Familiar AD cases have mislead some researchers for almost 20 years, which has unfortunately narrowed the scientific understanding and has, thus, lead to insufficient funding of independent approaches. Therefore, basic researchers hardly have been able to develop causative treatments and clinicians still do not have access to prognostic and early diagnostic tools. During the recent years it became clear that insufficient Aβ export, physiologically facilitated by the ABC transporter superfamily at the brain's barriers, plays a fundamental role in disease initiation and progression. Furthermore, export mechanisms that are deficient in affected elderly are new targets for activation and, thus, treatment, but ideally also for prevention. In sporadic AD disturbed clearance of β-amyloid from the brain is so far the most important factor for its accumulation in the parenchyma and vessel walls. Here, we review findings about the contribution of ABC transporters and of the perivascular drainage/glymphatic system on β-amyloid clearance. We highlight their potential value for innovative early diagnostics using PET and describe recently described, effective ABC transporter-targeting agents as potential causative treatment for neurodegenerative proteopathies/dementias. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. The ABC family of multidrug transporters in microorganisms

    NARCIS (Netherlands)

    van Veen, H.W; Konings, W.N

    1998-01-01

    Multidrug transporters are membrane proteins that are able to expel a broad range of toxic molecules from the cell. In humans, the overexpression of the multidrug resistance P-glycoprotein (Pgp) and the multidrug resistance-associated protein MRP1 (MRP) is a principal cause of resistance of cancers

  17. Computer-Aided Recognition of ABC Transporters Substrates and Its Application to the Development of New Drugs for Refractory Epilepsy.

    Science.gov (United States)

    Couyoupetrou, Manuel; Gantner, Melisa E; Di Ianni, Mauricio E; Palestro, Pablo H; Enrique, Andrea V; Gavernet, Luciana; Ruiz, Maria E; Pesce, Guido; Bruno-Blanch, Luis E; Talevi, Alan

    2017-01-01

    Despite the introduction of more than 15 third generation antiepileptic drugs to the market from 1990 to the moment, about one third of the epileptic patients still suffer from refractory to intractable epilepsy. Several hypotheses seek to explain the failure of drug treatments to control epilepsy symptoms in such patients. The most studied one proposes that drug resistance might be related with regional overactivity of efflux transporters from the ATP-Binding Cassette (ABC) superfamily at the blood-brain barrier and/or the epileptic foci in the brain. Different strategies have been conceived to address the transporter hypothesis, among them inhibiting or down-regulating the efflux transporters or bypassing them through a diversity of artifices. Here, we review scientific evidence supporting the transporter hypothesis along with its limitations, as well as computer-assisted early recognition of ABC transporter substrates as an interesting strategy to develop novel antiepileptic drugs capable of treating refractory epilepsy linked to ABC transporters overactivity.

  18. Simulation of the coupling between nucleotide binding and transmembrane domains in the ABC transporter BtuCD

    DEFF Research Database (Denmark)

    Sonne, Jacob; Kandt, C.; Peters, Günther H.j.

    2007-01-01

    binding domains and the shared role of ATP in ABC transporters. The rearrangements in the cytoplasmic gate region do not provide enough space for B12 to diffuse from the transporter pore into the cytoplasm, which could suggest that peristaltic forces are needed to exclude B12 from the transporter pore....

  19. Describing the role of Drosophila melanogaster ABC transporters in insecticide biology using CRISPR-Cas9 knockouts.

    Science.gov (United States)

    Denecke, Shane; Fusetto, Roberto; Batterham, Philip

    2017-12-01

    ABC transporters have a well-established role in drug resistance, effluxing xenobiotics from cells and tissues within the organism. More recently, research has been dedicated to understanding the role insect ABC transporters play in insecticide toxicity, but progress in understanding the contribution of specific transporters has been hampered by the lack of functional genetic tools. Here, we report knockouts of three Drosophila melanogaster ABC transporter genes, Mdr49, Mdr50, and Mdr65, that are homologous to the well-studied mammalian ABCB1 (P-glycoprotein). Each knockout mutant was created in the same wild type background and tested against a panel of insecticides representing different chemical classes. Mdr65 knockouts were more susceptible to all neuroactive insecticides tested, but Mdr49 and Mdr50 knockouts showed increased susceptibility or resistance depending on the insecticide used. Mdr65 was chosen for further analysis. Calculation of LC 50 values for the Mdr65 knockout allowed the substrate specificity of this transporter to be examined. No obvious distinguishing structural features were shared among MDR65 substrates. A role for Mdr65 in insecticide transport was confirmed by testing the capacity of the knockout to synergize with the ABC inhibitor verapamil and by measuring the levels of insecticide retained in the body of knockout flies. These data unambiguously establish the influence of ABC transporters on the capacity of wild type D. melanogaster to tolerate insecticide exposure and suggest that both tissue and substrate specificity underpin this capacity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. ATP-Binding Cassette (ABC) Transporters of the Human Respiratory Tract Pathogen, Moraxella catarrhalis: Role in Virulence.

    Science.gov (United States)

    Murphy, Timothy F; Brauer, Aimee L; Johnson, Antoinette; Kirkham, Charmaine

    2016-01-01

    Moraxella catarrhalis is a human respiratory tract pathogen that causes otitis media (middle ear infections) in children and respiratory tract infections in adults with chronic obstructive pulmonary disease. In view of the huge global burden of disease caused by M. catarrhalis, the development of vaccines to prevent these infections and better approaches to treatment have become priorities. In previous work, we used a genome mining approach that identified three substrate binding proteins (SBPs) of ATP-binding cassette (ABC) transporters as promising candidate vaccine antigens. In the present study, we performed a comprehensive assessment of 19 SBPs of 15 ABC transporter systems in the M. catarrhalis genome by engineering knockout mutants and studying their role in assays that assess mechanisms of infection. The capacity of M. catarrhalis to survive and grow in the nutrient-limited and hostile environment of the human respiratory tract, including intracellular growth, account in part for its virulence. The results show that ABC transporters that mediate uptake of peptides, amino acids, cations and anions play important roles in pathogenesis by enabling M. catarrhalis to 1) grow in nutrient-limited conditions, 2) invade and survive in human respiratory epithelial cells and 3) persist in the lungs in a murine pulmonary clearance model. The knockout mutants of SBPs and ABC transporters showed different patterns of activity in the assay systems, supporting the conclusion that different SBPs and ABC transporters function at different stages in the pathogenesis of infection. These results indicate that ABC transporters are nutritional virulence factors, functioning to enable the survival of M catarrhalis in the diverse microenvironments of the respiratory tract. Based on the role of ABC transporters as virulence factors of M. catarrhalis, these molecules represent potential drug targets to eradicate the organism from the human respiratory tract.

  1. Reversal of resistance by GF120918 in cell lines expressing the ABC half-transporter, MXR

    DEFF Research Database (Denmark)

    de Bruin, M; Miyake, K; Litman, Thomas

    1999-01-01

    The emergence of several newly identified members of the ABC transporter family has necessitated the development of antagonists that are able to inhibit more than one transporter. We assessed the ability of the chemosensitizer GF120918 to function as a multispecific antagonist using cytotoxicity...... assays, rhodamine and calcein efflux assays, and confocal microscopy in cell lines expressing different multidrug resistance transporters. At a concentration of 1 microM in cytotoxicity assays, GF120918 was able to sensitize both S1-B1-20, a subline expressing P-glycoprotein (Pgp), and S1-M1......-80, a subline expressing a newly identified mitoxantrone transporter, MXR. GF120918 was ineffective in sensitizing MRP-overexpressing MCF-7 VP-16 cells to etoposide as determined by cytotoxicity studies. In flow cytometry experiments, rhodamine 123 efflux in S1-B1-20 cells was decreased at GF120918...

  2. Purification and biochemical characterisation of the yeast ABC transporter Pdr11p

    DEFF Research Database (Denmark)

    Laub, Katrine Rude

    Sterols constitute an essential lipid class in eukaryotic membranes where intracellular distributions are highly regulated. In the yeast Saccharomyces cerevisiae sterol uptake has been attributed to the two plasma membrane-localised ATP-binding cassette (ABC) transporters, Aus1p and Pdr11p...... understanding of their action and molecular functioning, it is helpful to focus on homogeneous preparations of membrane proteins reconstituted into model membranes like detergent micelles, liposomes, and nanodiscs. In the present study, I report the first successful expression, purification, and reconstitution...

  3. Molecular characterization of ABC transporters in marine ciliate, Euplotes crassus: Identification and response to cadmium and benzo[a]pyrene.

    Science.gov (United States)

    Kim, Hokyun; Yim, Bora; Kim, Jisoo; Kim, Haeyeon; Lee, Young-Mi

    2017-11-30

    ATP-binding cassette (ABC) transporters participate in transporting various substances, including xenobiotics, in or out of cells. However, their genetic information and function in ciliates remain still unclear. In this study, we sequenced and characterized two ABC transporter genes (EcABCB and EcABCC), and investigated the effect of cadmium (Cd) and benzo[a]pyrene (B[a]P) on their function and gene expression, using efflux assay and real-time reverse transcription-polymerase chain reaction (qRT-PCR), respectively, in the marine ciliate, Euplotes crassus. Sequencing analysis and efflux assay showed that EcABCB and EcABCC are typical ABC transporters, possessing conserved function. Exposure to Cd (≥5mg/L) and B[a]P (≥50.5μg/L) enhanced accumulation of a substrate. A significant increase in the expression of EcABCB and EcABC mRNA was observed at lower concentration in response to Cd and B[a]P. Our findings indicate that Cd and B[a]P could inhibit the efflux function of ABC transporters, leading to cellular toxicity in the ciliate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Nucleotide dependent packing differences in helical crystals of the ABC transporter MsbA.

    Science.gov (United States)

    Ward, Andrew; Mulligan, Sheila; Carragher, Bridget; Chang, Geoffrey; Milligan, Ronald A

    2009-03-01

    Bacterial ATP binding cassette (ABC) exporters fulfill a wide variety of transmembrane transport roles and are homologous to the human multidrug resistance P-glycoprotein. Recent X-ray structures of the exporters MsbA and Sav1866 have begun to describe the conformational changes that accompany the ABC transport cycle. Here we present cryo-electron microscopy structures of MsbA reconstituted into a lipid bilayer. Using ATPase inhibitors, we captured three nucleotide transition states of the transporter that were subsequently reconstituted into helical arrays. The enzyme-substrate complex (trapped by ADP-aluminum fluoride or AMPPNP) crystallized in a different helical lattice than the enzyme-product complex (trapped by ADP-vanadate). Approximately 20A resolution maps were calculated for each state and revealed MsbA to be a dimer with a large channel between the membrane spanning domains, similar to the outward facing crystal structures of MsbA and Sav1866. This suggests that while there are likely structural differences between the nucleotide transition states, membrane embedded MsbA remains in an outward facing conformation while nucleotide is bound.

  5. The role of ATP-binding cassette (ABC) transporters in pathogenesis and multidrug resistance of the wheat pathogen Mycosphaerella graminicola

    NARCIS (Netherlands)

    Stergiopoulos, I.

    2003-01-01

    ATP-binding cassette (ABC) transporters are membrane proteins that utilise the energy derived from the hydrolysis of ATP to drive the transport of compounds over biological membranes. They are members of one of the largest protein families to date, present in both pro- and eukaryotic

  6. Changes in metabolism affect expression of ABC transporters through ERK5 and depending on p53 status.

    Science.gov (United States)

    Belkahla, Sana; Haq Khan, Abrar Ul; Gitenay, Delphine; Alexia, Catherine; Gondeau, Claire; Vo, Dang-Nghiem; Orecchioni, Stefania; Talarico, Giovanna; Bertolini, Francesco; Cartron, Guillaume; Hernandez, Javier; Daujat-Chavanieu, Martine; Allende-Vega, Nerea; Gonzalez, Martin Villalba

    2018-01-02

    Changes in metabolism require the efflux and influx of a diverse variety of metabolites. The ABC superfamily of transporters regulates the exchange of hundreds of substrates through the impermeable cell membrane. We show here that a metabolic switch to oxidative phosphorylation (OXPHOS), either by treating cells with dichloroacetate (DCA) or by changing the available substrates, reduced expression of ABCB1, ABCC1, ABCC5 and ABCG2 in wild-type p53-expressing cells. This metabolic change reduced histone changes associated to active promoters. Notably, DCA also inhibited expression of these genes in two animal models in vivo . In contrast, OXPHOS increased the expression of the same transporters in mutated (mut) or null p53-expressing cells. ABC transporters control the export of drugs from cancer cells and render tumors resistant to chemotherapy, playing an important role in multiple drug resistance (MDR). Wtp53 cells forced to perform OXPHOS showed impaired drug clearance. In contrast mutp53 cells increased drug clearance when performing OXPHOS. ABC transporter promoters contain binding sites for the transcription factors MEF2, NRF1 and NRF2 that are targets of the MAPK ERK5. OXPHOS induced expression of the MAPK ERK5. Decreasing ERK5 levels in wtp53 cells increased ABC expression whereas it inhibited expression in mutp53 cells. Our results showed that the ERK5/MEF2 pathway controlled ABC expression depending on p53 status.

  7. ABC Transporter Subfamily D: Distinct Differences in Behavior between ABCD1–3 and ABCD4 in Subcellular Localization, Function, and Human Disease

    Science.gov (United States)

    2016-01-01

    ATP-binding cassette (ABC) transporters are one of the largest families of membrane-bound proteins and transport a wide variety of substrates across both extra- and intracellular membranes. They play a critical role in maintaining cellular homeostasis. To date, four ABC transporters belonging to subfamily D have been identified. ABCD1–3 and ABCD4 are localized to peroxisomes and lysosomes, respectively. ABCD1 and ABCD2 are involved in the transport of long and very long chain fatty acids (VLCFA) or their CoA-derivatives into peroxisomes with different substrate specificities, while ABCD3 is involved in the transport of branched chain acyl-CoA into peroxisomes. On the other hand, ABCD4 is deduced to take part in the transport of vitamin B12 from lysosomes into the cytosol. It is well known that the dysfunction of ABCD1 results in X-linked adrenoleukodystrophy, a severe neurodegenerative disease. Recently, it is reported that ABCD3 and ABCD4 are responsible for hepatosplenomegaly and vitamin B12 deficiency, respectively. In this review, the targeting mechanism and physiological functions of the ABCD transporters are summarized along with the related disease. PMID:27766264

  8. ABC Transporter Subfamily D: Distinct Differences in Behavior between ABCD1-3 and ABCD4 in Subcellular Localization, Function, and Human Disease.

    Science.gov (United States)

    Kawaguchi, Kosuke; Morita, Masashi

    2016-01-01

    ATP-binding cassette (ABC) transporters are one of the largest families of membrane-bound proteins and transport a wide variety of substrates across both extra- and intracellular membranes. They play a critical role in maintaining cellular homeostasis. To date, four ABC transporters belonging to subfamily D have been identified. ABCD1-3 and ABCD4 are localized to peroxisomes and lysosomes, respectively. ABCD1 and ABCD2 are involved in the transport of long and very long chain fatty acids (VLCFA) or their CoA-derivatives into peroxisomes with different substrate specificities, while ABCD3 is involved in the transport of branched chain acyl-CoA into peroxisomes. On the other hand, ABCD4 is deduced to take part in the transport of vitamin B 12 from lysosomes into the cytosol. It is well known that the dysfunction of ABCD1 results in X-linked adrenoleukodystrophy, a severe neurodegenerative disease. Recently, it is reported that ABCD3 and ABCD4 are responsible for hepatosplenomegaly and vitamin B 12 deficiency, respectively. In this review, the targeting mechanism and physiological functions of the ABCD transporters are summarized along with the related disease.

  9. ABC Transporter Subfamily D: Distinct Differences in Behavior between ABCD1–3 and ABCD4 in Subcellular Localization, Function, and Human Disease

    Directory of Open Access Journals (Sweden)

    Kosuke Kawaguchi

    2016-01-01

    Full Text Available ATP-binding cassette (ABC transporters are one of the largest families of membrane-bound proteins and transport a wide variety of substrates across both extra- and intracellular membranes. They play a critical role in maintaining cellular homeostasis. To date, four ABC transporters belonging to subfamily D have been identified. ABCD1–3 and ABCD4 are localized to peroxisomes and lysosomes, respectively. ABCD1 and ABCD2 are involved in the transport of long and very long chain fatty acids (VLCFA or their CoA-derivatives into peroxisomes with different substrate specificities, while ABCD3 is involved in the transport of branched chain acyl-CoA into peroxisomes. On the other hand, ABCD4 is deduced to take part in the transport of vitamin B12 from lysosomes into the cytosol. It is well known that the dysfunction of ABCD1 results in X-linked adrenoleukodystrophy, a severe neurodegenerative disease. Recently, it is reported that ABCD3 and ABCD4 are responsible for hepatosplenomegaly and vitamin B12 deficiency, respectively. In this review, the targeting mechanism and physiological functions of the ABCD transporters are summarized along with the related disease.

  10. Using mass spectrometry for identification of ABC transporters from Xanthomonas citri and mutants expressed in different growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Faria, J.N.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil); Paes Leme, A.F. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)

    2012-07-01

    Full text: Xanthomonas citri is a phytopathogenic bacterium that infects citrus plants causing significant losses for the economy. In our group, we have focused on the identification and characterization of ABC transport proteins of this bacterium, in order to determinate their function for growth in vitro and in vivo, during infection. ABC transporters represent one of the largest families of proteins, which transport since small molecules as ions up to oligopeptides and sugars. In prokaryotic cells many works have reported the ABC transport function in pathogenesis, resistance, biofilm formation, infectivity and DNA repair, but until our knowledge, there is no data related to these transporters and X. citri. So, In order to determinate which transporters are expressed in X. citri, we started a proteomic analysis based on mono and bi-dimensional gels associated to mass spectrometry analyses. After growing X. citri and two different mutants deleted for ssuA and nitA genes in LB and minimum media, cellular extracts were obtained and used for preparation of mono and bi-dimensional gels. Seven bands covering the expected mass of ABC transporter components (20 kDa to 50 kDa) in SDS-PAGE were cut off the gel, treated with trypsin and submitted to the MS for protein identification. The results of 2D gels were good enough and will serve as a standard for development of similar experiments in large scale. (author)

  11. Genome-Wide Identification, Characterization and Phylogenetic Analysis of ATP-Binding Cassette (ABC) Transporter Genes in Common Carp (Cyprinus carpio).

    Science.gov (United States)

    Liu, Xiang; Li, Shangqi; Peng, Wenzhu; Feng, Shuaisheng; Feng, Jianxin; Mahboob, Shahid; Al-Ghanim, Khalid A; Xu, Peng

    2016-01-01

    The ATP-binding cassette (ABC) gene family is considered to be one of the largest gene families in all forms of prokaryotic and eukaryotic life. Although the ABC transporter genes have been annotated in some species, detailed information about the ABC superfamily and the evolutionary characterization of ABC genes in common carp (Cyprinus carpio) are still unclear. In this research, we identified 61 ABC transporter genes in the common carp genome. Phylogenetic analysis revealed that they could be classified into seven subfamilies, namely 11 ABCAs, six ABCBs, 19 ABCCs, eight ABCDs, two ABCEs, four ABCFs, and 11 ABCGs. Comparative analysis of the ABC genes in seven vertebrate species including common carp, showed that at least 10 common carp genes were retained from the third round of whole genome duplication, while 12 duplicated ABC genes may have come from the fourth round of whole genome duplication. Gene losses were also observed for 14 ABC genes. Expression profiles of the 61 ABC genes in six common carp tissues (brain, heart, spleen, kidney, intestine, and gill) revealed extensive functional divergence among the ABC genes. Different copies of some genes had tissue-specific expression patterns, which may indicate some gene function specialization. This study provides essential genomic resources for future studies in common carp.

  12. The product of the ABC half-transporter gene ABCG2 (BCRP/MXR/ABCP) is expressed in the plasma membrane

    DEFF Research Database (Denmark)

    Rocchi, E; Khodjakov, A; Volk, E L

    2000-01-01

    The products of the ABC gene family can be generally classified as either full-transporters of half-transporters. Full-transporters are expressed in the plasma membrane, whereas half-transporters are usually found in intracellular membranes. Recently, an ABC half-transporter, the ABCG2 gene product...... by Western blot and immunohistochemistry. This protein is highly overexpressed in several drug-resistant cell lines and localizes predominantly to the plasma membrane, instead of to intracellular membranes as seen with all other known half-transporters. Therefore, BCRP/MXR is unique among the ABC half...

  13. Identification of Residues in the Lipopolysaccharide ABC Transporter That Coordinate ATPase Activity with Extractor Function.

    Science.gov (United States)

    Simpson, Brent W; Owens, Tristan W; Orabella, Matthew J; Davis, Rebecca M; May, Janine M; Trauger, Sunia A; Kahne, Daniel; Ruiz, Natividad

    2016-10-18

    The surface of most Gram-negative bacteria is covered with lipopolysaccharide (LPS), creating a permeability barrier against toxic molecules, including many antimicrobials. To assemble LPS on their surface, Gram-negative bacteria must extract newly synthesized LPS from the inner membrane, transport it across the aqueous periplasm, and translocate it across the outer membrane. The LptA to -G proteins assemble into a transenvelope complex that transports LPS from the inner membrane to the cell surface. The Lpt system powers LPS transport from the inner membrane by using a poorly characterized ATP-binding cassette system composed of the ATPase LptB and the transmembrane domains LptFG. Here, we characterize a cluster of residues in the groove region of LptB that is important for controlling LPS transport. We also provide the first functional characterization of LptFG and identify their coupling helices that interact with the LptB groove. Substitutions at conserved residues in these coupling helices compromise both the assembly and function of the LptB 2 FG complex. Defects in LPS transport conferred by alterations in the LptFG coupling helices can be rescued by changing a residue in LptB that is adjacent to functionally important residues in the groove region. This suppression is achieved by increasing the ATPase activity of the LptB 2 FG complex. Taken together, these data identify a specific binding site in LptB for the coupling helices of LptFG that is responsible for coupling of ATP hydrolysis by LptB with LptFG function to achieve LPS extraction. Lipopolysaccharide (LPS) is synthesized at the cytoplasmic membrane of Gram-negative bacteria and transported across several compartments to the cell surface, where it forms a barrier that protects these organisms from antibiotics. The LptB 2 FG proteins form an ATP-binding cassette (ABC) transporter that uses energy from ATP hydrolysis in the cytoplasm to facilitate extraction of LPS from the outer face of the

  14. ABC- and SLC-Transporters in Murine and Bovine Mammary Epithelium--Effects of Prochloraz.

    Directory of Open Access Journals (Sweden)

    Yagmur Yagdiran

    Full Text Available Some chemicals are ligands to efflux transporters which may result in high concentrations in milk. Limited knowledge is available on the influence of maternal exposure to chemicals on the expression and function of transporters in the lactating mammary gland. We determined gene expression of ABC and SLC transporters in murine mammary tissue of different gestation and lactation stages, in murine mammary cells (HC11 featuring resting and secreting phenotypes and in bovine mammary tissue and cells (BME-UV. Effects on transporter expression and function of the imidazole fungicide prochloraz, previously reported to influence BCRP in mammary cells, was investigated on transporter expression and function in the two cell lines. Transporters studied were BCRP, MDR1, MRP1, OATP1A5/OATP1A2, OCTN1 and OCT1. Gene expressions of BCRP and OCT1 in murine mammary glands were increased during gestation and lactation, whereas MDR1, MRP1, OATP1A5 and OCTN1 were decreased, compared to expressions in virgins. All transporters measured in mammary glands of mice were detected in bovine mammary tissue and in HC11 cells, while only MDR1 and MRP1 were detected in BME-UV cells. Prochloraz treatment induced MDR1 gene and protein expression in both differentiated HC11 and BME-UV cells and increased protein function in HC11 cells, resulting in decreased accumulation of the MDR1 substrate digoxin. In conclusion, our results demonstrate that murine (HC11 and bovine (BME-UV mammary epithelial cells can be applied to characterize expression and function of transporters as well as effects of contaminants on the mammary transporters. An altered expression, induced by a drug or toxic chemical, on any of the transporters expressed in the mammary epithelial cells during lactation may modulate the well-balanced composition of nutrients and/or secretion of contaminants in milk with potential adverse effects on breast-fed infants and dairy consumers.

  15. Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Svenningsen, Katrine; Almind Knudsen, Lina

    2015-01-01

    AIM: To evaluate ATP-binding cassette (ABC) transporters in colonic pathophysiology as they had recently been related to colorectal cancer (CRC) development. METHODS: Literature search was conducted on PubMed using combinations of the following terms: ABC transporters, ATP binding cassette....../Mdr1a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function. RESULTS: Recently, human studies reported that changes in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes...... translocation from one side to the other of the cell membrane lipid bilayer by ABC transporters affecting inflammatory response and/or function of tight junctions, phagocytosis and vesicle trafficking. Also, diet and microbes give rise to molecules which are potential substrates for the ABC transporters...

  16. Molybdate transporter ModABC is important for Pseudomonas aeruginosa chronic lung infection.

    Science.gov (United States)

    Périnet, Simone; Jeukens, Julie; Kukavica-Ibrulj, Irena; Ouellet, Myriam M; Charette, Steve J; Levesque, Roger C

    2016-01-12

    Mechanisms underlying the success of Pseudomonas aeruginosa in chronic lung infection among cystic fibrosis (CF) patients are poorly defined. The modA gene was previously linked to in vivo competitiveness of P. aeruginosa by a genetic screening in the rat lung. This gene encodes a subunit of transporter ModABC, which is responsible for extracellular uptake of molybdate. This compound is essential for molybdoenzymes, including nitrate reductases. Since anaerobic growth conditions are known to occur during CF chronic lung infection, inactivation of a molybdate transporter could inhibit proliferation through the inactivation of denitrification enzymes. Hence, we performed phenotypic characterization of a modA mutant strain obtained by signature-tagged mutagenesis (STM_modA) and assessed its virulence in vivo with two host models. The STM_modA mutant was in fact defective for anaerobic growth and unable to use nitrates in the growth medium for anaerobic respiration. Bacterial growth and nitrate usage were restored when the medium was supplemented with molybdate. Most significantly, the mutant strain showed reduced virulence compared to wild-type strain PAO1 according to a competitive index in the rat model of chronic lung infection and a predation assay with Dictyostelium discoideum amoebae. As the latter took place in aerobic conditions, the in vivo impact of the mutation in modA appears to extend beyond its effect on anaerobic growth. These results support the modABC-encoded transporter as important for the pathogenesis of P. aeruginosa, and suggest that enzymatic machinery implicated in anaerobic growth during chronic lung infection in CF merits further investigation as a potential target for therapeutic intervention.

  17. Specificity of the second binding protein of the peptide ABC-transporter (Dpp) of Lactococcus lactis IL1403

    NARCIS (Netherlands)

    Sanz, Y; Toldra, F; Renault, P; Poolman, B

    2003-01-01

    The genome sequence of Lactococcus lactis IL1403 revealed the presence of a putative peptide-binding protein-dependent ABC-transporter (Dpp). The genes for two peptide-binding proteins (dppA and dppP) precede the membrane components, which include two transmembrane protein genes (dppB and dppC) and

  18. Human and Rat ABC Transporter Efflux of Bisphenol A and Bisphenol A Glucuronide: Interspecies Comparison and Implications for Pharmacokinetic Assessment

    Science.gov (United States)

    Significant interspecies differences exist between human and rodent with respect to absorption, distribution, and excretion of bisphenol A (BPA) and its primary metabolite, BPA-glucuronide (BPA-G). ATP-Binding Cassette (ABC) transporter enzymes play important roles in these physi...

  19. An ABC transporter controls export of a Drosophila germ cell attractant.

    Science.gov (United States)

    Ricardo, Sara; Lehmann, Ruth

    2009-02-13

    Directed cell migration, which is critical for embryonic development, leukocyte trafficking, and cell metastasis, depends on chemoattraction. 3-hydroxy-3-methylglutaryl coenzyme A reductase regulates the production of an attractant for Drosophila germ cells that may itself be geranylated. Chemoattractants are commonly secreted through a classical, signal peptide-dependent pathway, but a geranyl-modified attractant would require an alternative pathway. In budding yeast, pheromones produced by a-cells are farnesylated and secreted in a signal peptide-independent manner, requiring the adenosine triphosphate-binding cassette (ABC) transporter Ste6p. Here we show that Drosophila germ cell migration uses a similar pathway, demonstrating that invertebrate germ cells, like yeast cells, are attracted to lipid-modified peptides. Components of this unconventional export pathway are highly conserved, suggesting that this pathway may control the production of similarly modified chemoattractants in organisms ranging from yeast to humans.

  20. Genetic variation in ABC transporter A1 contributes to HDL cholesterol in the general population

    DEFF Research Database (Denmark)

    Frikke-Schmidt, Ruth; Nordestgaard, Børge G; Jensen, Gorm B

    2004-01-01

    or single-nucleotide polymorphisms (SNPs) in ABCA1 were overrepresented in individuals with the lowest 1% (n=95) or highest 1% (n=95) HDL-C levels in the general population by screening the core promoter and coding region of ABCA1. For all nonsynonymous SNPs identified, we determined the effect of genotype......Homozygosity for mutations in ABC transporter A1 (ABCA1) causes Tangier disease, a rare HDL-deficiency syndrome. Whether heterozygosity for genetic variation in ABCA1 also contributes to HDL cholesterol (HDL-C) levels in the general population is presently unclear. We determined whether mutations...... on lipid traits in 9,259 individuals from the general population. Heterozygosity for ABCA1 mutations was identified in 10% of individuals with low HDL-C only. Three of 6 nonsynonymous SNPs (V771M, V825I, and R1587K) were associated with increases or decreases in HDL-C in women in the general population...

  1. The ABC of ECF transporters : discovery and initial characterization of ECF-type ATP-binding casette (ABC) importers

    NARCIS (Netherlands)

    ter Beek, Josy

    2012-01-01

    Josy ter Beek heeft een nieuwe klasse transporteiwitten in de celmembraan ontdekt en gekarakteriseerd. Aangezien deze transporter alleen door bacteriën wordt gebruikt en voor het transport van verscheidene belangrijke stoffen zorgt, kan informatie over deze nieuwe klasse transporters in de toekomst

  2. Control of Insulin Granule Formation and Function by the ABC Transporters ABCG1 and ABCA1 and by Oxysterol Binding Protein OSBP.

    Science.gov (United States)

    Hussain, Syed Saad; Harris, Megan T; Kreutzberger, Alex J B; Inouye, Candice M; Doyle, Catherine A; Castle, Anna M; Arvan, Peter; Castle, J David

    2018-03-14

    In pancreatic β cells, insulin granule membranes are enriched in cholesterol and are both recycled and newly generated. Cholesterol's role in supporting granule membrane formation and function is poorly understood. A TP b inding c assette transporters ABCG1 and ABCA1 regulate intracellular cholesterol and are important for insulin secretion. RNAi-induced depletion in cultured pancreatic β cells shows that ABCG1 is needed to stabilize newly made insulin granules against lysosomal degradation; ABCA1 is also involved but to a lesser extent. Both transporters are also required for optimum glucose-stimulated insulin secretion, likely via complementary roles. Exogenous cholesterol addition rescues knockdown-induced granule loss (ABCG1) and reduced secretion (both transporters). Another cholesterol transport protein, oxysterol binding protein (OSBP) appears to act proximally as a source of endogenous cholesterol for granule formation. Its knockdown caused similar defective stability of young granules and glucose-stimulated insulin secretion, neither of which were rescued with exogenous cholesterol. Dual knockdowns of OSBP and ABC transporters support their serial function in supplying and concentrating cholesterol for granule formation. OSBP knockdown also decreased proinsulin synthesis consistent with a proximal ER defect. Thus, membrane cholesterol distribution contributes to insulin homeostasis at production, packaging and export levels through the actions of OSBP and ABCs G1 and A1. © 2018 by The American Society for Cell Biology.

  3. Enterococcus faecalis Uses a Phosphotransferase System Permease and a Host Colonization-Related ABC Transporter for Maltodextrin Uptake.

    Science.gov (United States)

    Sauvageot, Nicolas; Mokhtari, Abdelhamid; Joyet, Philippe; Budin-Verneuil, Aurélie; Blancato, Víctor S; Repizo, Guillermo D; Henry, Céline; Pikis, Andreas; Thompson, John; Magni, Christian; Hartke, Axel; Deutscher, Josef

    2017-05-01

    Maltodextrin is a mixture of maltooligosaccharides, which are produced by the degradation of starch or glycogen. They are mostly composed of α-1,4- and some α-1,6-linked glucose residues. Genes presumed to code for the Enterococcus faecalis maltodextrin transporter were induced during enterococcal infection. We therefore carried out a detailed study of maltodextrin transport in this organism. Depending on their length (3 to 7 glucose residues), E. faecalis takes up maltodextrins either via MalT, a maltose-specific permease of the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS), or the ATP binding cassette (ABC) transporter MdxEFG-MsmX. Maltotriose, the smallest maltodextrin, is primarily transported by the PTS permease. A malT mutant therefore exhibits significantly reduced growth on maltose and maltotriose. The residual uptake of the trisaccharide is catalyzed by the ABC transporter, because a malT mdxF double mutant no longer grows on maltotriose. The trisaccharide arrives as maltotriose-6″-P in the cell. MapP, which dephosphorylates maltose-6'-P, also releases P i from maltotriose-6″-P. Maltotetraose and longer maltodextrins are mainly (or exclusively) taken up via the ABC transporter, because inactivation of the membrane protein MdxF prevents growth on maltotetraose and longer maltodextrins up to at least maltoheptaose. E. faecalis also utilizes panose and isopanose, and we show for the first time, to our knowledge, that in contrast to maltotriose, its two isomers are primarily transported via the ABC transporter. We confirm that maltodextrin utilization via MdxEFG-MsmX affects the colonization capacity of E. faecalis , because inactivation of mdxF significantly reduced enterococcal colonization and/or survival in kidneys and liver of mice after intraperitoneal infection. IMPORTANCE Infections by enterococci, which are major health care-associated pathogens, are difficult to treat due to their increasing resistance to clinically

  4. PPAR Medicines and Human Disease: The ABCs of It All

    Directory of Open Access Journals (Sweden)

    Anthony J. Apostoli

    2012-01-01

    Full Text Available ATP-dependent binding cassette (ABC transporters are a family of transmembrane proteins that pump a variety of hydrophobic compounds across cellular and subcellular barriers and are implicated in human diseases such as cancer and atherosclerosis. Inhibition of ABC transporter activity showed promise in early preclinical studies; however, the outcomes in clinical trials with these agents have not been as encouraging. Peroxisome proliferator-activated receptors (PPARs are ligand-activated transcription factors that regulate genes involved in fat and glucose metabolism, and inflammation. Activation of PPAR signaling is also reported to regulate ABC gene expression. This suggests the potential of PPAR medicines as a novel means of controlling ABC transporter activity at the transcriptional level. This paper summarizes the advances made in understanding how PPAR medicines affect ABC transporters, and the potential implications for impacting on human diseases, in particular with respect to cancer and atherosclerosis.

  5. The ABC of Biofilm Drug Tolerance: the MerR-Like Regulator BrlR Is an Activator of ABC Transport Systems, with PA1874-77 Contributing to the Tolerance of Pseudomonas aeruginosa Biofilms to Tobramycin.

    Science.gov (United States)

    Poudyal, Bandita; Sauer, Karin

    2018-02-01

    A hallmark of biofilms is their tolerance to killing by antimicrobial agents. In Pseudomonas aeruginosa , biofilm drug tolerance requires the c-di-GMP-responsive MerR transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm drug tolerance has not been elucidated. Here, we demonstrate that BrlR activates the expression of at least 7 ABC transport systems, including the PA1874-PA1875-PA1876-PA1877 (PA1874-77) operon, with chromatin immunoprecipitation and DNA binding assays confirming BrlR binding to the promoter region of PA1874-77. Insertional inactivation of the 7 ABC transport systems rendered P. aeruginosa PAO1 biofilms susceptible to tobramycin or norfloxacin. Susceptibility was linked to drug accumulation, with BrlR contributing to norfloxacin accumulation in a manner dependent on multidrug efflux pumps and the PA1874-77 ABC transport system. Inactivation of the respective ABC transport system, furthermore, eliminated the recalcitrance of biofilms to killing by tobramycin but not norfloxacin, indicating that drug accumulation is not linked to biofilm drug tolerance. Our findings indicate for the first time that BrlR, a MerR-type transcriptional activator, activates genes encoding several ABC transport systems, in addition to multiple multidrug efflux pump genes. Moreover, our data confirm a BrlR target contributing to drug tolerance, likely countering the prevailing dogma that biofilm tolerance arises from a multiplicity of factors. Copyright © 2018 American Society for Microbiology.

  6. Plant ABC proteins--a unified nomenclature and updated inventory.

    Science.gov (United States)

    Verrier, Paul J; Bird, David; Burla, Bo; Dassa, Elie; Forestier, Cyrille; Geisler, Markus; Klein, Markus; Kolukisaoglu, Uner; Lee, Youngsook; Martinoia, Enrico; Murphy, Angus; Rea, Philip A; Samuels, Lacey; Schulz, Burkhard; Spalding, Edgar J; Yazaki, Kazufumi; Theodoulou, Frederica L

    2008-04-01

    The ABC superfamily comprises both membrane-bound transporters and soluble proteins involved in a broad range of processes, many of which are of considerable agricultural, biotechnological and medical potential. Completion of the Arabidopsis and rice genome sequences has revealed a particularly large and diverse complement of plant ABC proteins in comparison with other organisms. Forward and reverse genetics, together with heterologous expression, have uncovered many novel roles for plant ABC proteins, but this progress has been accompanied by a confusing proliferation of names for plant ABC genes and their products. A consolidated nomenclature will provide much-needed clarity and a framework for future research.

  7. In Vitro and Ex Vivo Model Systems to Measure ABC Transporter Activity at the Blood-Brain Barrier.

    Science.gov (United States)

    de Wit, Nienke M; Kooij, Gijs; de Vries, Helga E

    2016-01-01

    With the aging population the occurrence of central nervous system diseases such as cancer, mental disorders and neurodegenerative diseases, is expected to increase and hence, the demand for effective drugs. However, the passage of drugs across the blood-brain barrier represents a major challenge in accomplishing efficient brain delivery of therapeutic agents. This highly efficient barrier is composed of a monolayer of capillary endothelial cells supported by pericytes and astrocytic end-feet, that together effectively shield the brain from the blood. The brain microvascular endothelial cells form a physical and metabolic barrier where paracellular and transcellular transport of molecules in and out of the brain is closely regulated, allowing nutrients to pass but preventing the entry of harmful neurotoxic substances, including drugs. For this purpose brain endothelial cells express efficient efflux pumps, such as ATP binding cassette (ABC) transporters, which limit the delivery of drugs into the brain. To treat the above-mentioned chronic central nervous system disorders, it is crucial to design compounds that can pass the blood-brain barrier and thus the ABC transporters. In order to achieve this, representative models of the blood-brain barrier with predictive validity are necessary. This review discusses the current in vitro and ex vivo model systems that are used to measure ABC transporter activity in order to study potential in vivo efficacy of blood-brain barrier-drug passage.

  8. Tuning the drug efflux activity of an ABC transporter in vivo by in vitro selected DARPin binders.

    Directory of Open Access Journals (Sweden)

    Markus A Seeger

    Full Text Available ABC transporters use the energy from binding and hydrolysis of ATP to import or extrude substrates across the membrane. Using ribosome display, we raised designed ankyrin repeat proteins (DARPins against detergent solubilized LmrCD, a heterodimeric multidrug ABC exporter from Lactococcus lactis. Several target-specific DARPin binders were identified that bind to at least three distinct, partially overlapping epitopes on LmrD in detergent solution as well as in native membranes. Remarkably, functional screening of the LmrCD-specific DARPin pools in L. lactis revealed three homologous DARPins which, when generated in LmrCD-expressing cells, strongly activated LmrCD-mediated drug transport. As LmrCD expression in the cell membrane was unaltered upon the co-expression of activator DARPins, the activation is suggested to occur at the level of LmrCD activity. Consistent with this, purified activator DARPins were found to stimulate the ATPase activity of LmrCD in vitro when reconstituted in proteoliposomes. This study suggests that membrane transporters are tunable in vivo by in vitro selected binding proteins. Our approach could be of biopharmaceutical importance and might facilitate studies on molecular mechanisms of ABC transporters.

  9. Chorioamnionitis Induces a Specific Signature of Placental ABC Transporters Associated with an Increase of miR-331-5p in the Human Preterm Placenta.

    Science.gov (United States)

    do Imperio, Guinever Eustaquio; Bloise, Enrrico; Javam, Mohsen; Lye, Phetcharawan; Constantinof, Andrea; Dunk, Caroline; Dos Reis, Fernando Marcos; Lye, Stephen James; Gibb, William; Ortiga-Carvalho, Tania M; Matthews, Stephen Giles

    2018-01-01

    The ATP-binding cassette (ABC) transporters mediate drug biodisposition and immunological responses in the placental barrier. In vitro infective challenges alter expression of specific placental ABC transporters. We hypothesized that chorioamnionitis induces a distinct pattern of ABC transporter expression. Gene expression of 50 ABC transporters was assessed using TaqMan® Human ABC Transporter Array, in preterm human placentas without (PTD; n=6) or with histological chorioamnionitis (PTDC; n=6). Validation was performed using qPCR, immunohistochemistry and Western blot. MicroRNAs known to regulate P-glycoprotein (P-gp) were examined by qPCR. Up-regulation of ABCB9, ABCC2 and ABCF2 mRNA was detected in chorioamnionitis (pABC transporters will likely lead to modified transport of clinically relevant compounds at the inflamed placenta. A better understanding of the potential role of these transporters in the events surrounding PTD may also enable new strategies to be developed for prevention and treatment of PTD. © 2018 The Author(s). Published by S. Karger AG, Basel.

  10. Beyond Competitive Inhibition: Regulation of ABC Transporters by Kinases and Protein-Protein Interactions as Potential Mechanisms of Drug-Drug Interactions.

    Science.gov (United States)

    Crawford, Rebecca R; Potukuchi, Praveen K; Schuetz, Erin G; Schuetz, John D

    2018-03-07

    ATP-binding cassette (ABC) transporters are transmembrane efflux transporters mediating the extrusion of an array of substrates ranging from amino acids and lipids to xenobiotics, and many therapeutic compounds, including anticancer drugs. The ABC transporters are also recognized as important contributors to pharmacokinetics, especially in drug-drug interactions and adverse drug effects. Drugs and xenobiotics, as well as pathological conditions, can influence the transcription of ABC transporters, or modify their activity or intracellular localization. Kinases can affect the aforementioned processes for ABC transporters as do protein interactions. In this review, we focus on the ABC transporters ABCB1, ABCB11, ABCC1, ABCC4 and ABCG2 and illustrate how kinases and protein-protein interactions affect these transporters. The clinical relevance of these factors is currently unknown, however these examples suggest that our understanding of drug-drug interactions will benefit from further knowledge of how kinases and protein-protein interactions affect ABC transporters. The American Society for Pharmacology and Experimental Therapeutics.

  11. Co-Induction of a Glutathione-S-transferase, a Glutathione Transporter and an ABC Transporter in Maize by Xenobiotics

    Science.gov (United States)

    Liu, Zhiqian; Song, Xiaoyu; Li, Xuefeng; Wang, Chengju

    2012-01-01

    Glutathione conjugation reactions are one of the principal mechanisms that plants utilize to detoxify xenobiotics. The induction by four herbicides (2,4-D, atrazine, metolachlor and primisulfuron) and a herbicide safener (dichlormid) on the expression of three genes, ZmGST27, ZmGT1 and ZmMRP1, encoding respectively a glutathione-S-transferase, a glutathione transporter and an ATP-binding cassette (ABC) transporter was studied in maize. The results demonstrate that the inducing effect on gene expression varies with both chemicals and genes. The expression of ZmGST27 and ZmMRP1 was up-regulated by all five compounds, whereas that of ZmGT1 was increased by atrazine, metolachlor, primisulfuron and dichlormid, but not by 2,4-D. For all chemicals, the inducing effect was first detected on ZmGST27. The finding that ZmGT1 is activated alongside ZmGST27 and ZmMRP1 suggests that glutathione transporters are an important component in the xenobiotic detoxification system of plants. PMID:22792398

  12. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein.

    Directory of Open Access Journals (Sweden)

    Wee Tek Tay

    2015-11-01

    Full Text Available The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the

  13. Detoxification of multiple heavy metals by a half-molecule ABC transporter, HMT-1, and coelomocytes of Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Marc S Schwartz

    2010-03-01

    Full Text Available Developing methods for protecting organisms in metal-polluted environments is contingent upon our understanding of cellular detoxification mechanisms. In this regard, half-molecule ATP-binding cassette (ABC transporters of the HMT-1 subfamily are required for cadmium (Cd detoxification. HMTs have conserved structural architecture that distinguishes them from other ABC transporters and allows the identification of homologs in genomes of different species including humans. We recently discovered that HMT-1 from the simple, unicellular organism, Schizosaccharomyces pombe, SpHMT1, acts independently of phytochelatin synthase (PCS and detoxifies Cd, but not other heavy metals. Whether HMTs from multicellular organisms confer tolerance only to Cd or also to other heavy metals is not known.Using molecular genetics approaches and functional in vivo assays we showed that HMT-1 from a multicellular organism, Caenorhabditis elegans, functions distinctly from its S. pombe counterpart in that in addition to Cd it confers tolerance to arsenic (As and copper (Cu while acting independently of pcs-1. Further investigation of hmt-1 and pcs-1 revealed that these genes are expressed in different cell types, supporting the notion that hmt-1 and pcs-1 operate in distinct detoxification pathways. Interestingly, pcs-1 and hmt-1 are co-expressed in highly endocytic C. elegans cells with unknown function, the coelomocytes. By analyzing heavy metal and oxidative stress sensitivities of the coelomocyte-deficient C. elegans strain we discovered that coelomocytes are essential mainly for detoxification of heavy metals, but not of oxidative stress, a by-product of heavy metal toxicity.We established that HMT-1 from the multicellular organism confers tolerance to multiple heavy metals and is expressed in liver-like cells, the coelomocytes, as well as head neurons and intestinal cells, which are cell types that are affected by heavy metal poisoning in humans. We also showed

  14. Quantitative structure-activity relationship (QSAR) analysis to predict drug-drug interactions of ABC transporter ABCG2.

    Science.gov (United States)

    Ishikawa, T; Hirano, H; Saito, H; Sano, K; Ikegami, Y; Yamaotsu, N; Hirono, S

    2012-06-01

    Quantitative structure-activity relationship (QSAR) analysis is a practical approach by which chemical structure is quantitatively correlated with biological activity or chemical reactivity. Human ABC transporter ABCG2 exhibits broad substrate specificity toward structurally diverse compounds. To gain insight into the relationship between the molecular structures of compounds and the interaction with ABCG2, we have developed an algorithm that analyzes QSAR to evaluate ABCG2-drug interactions. In addition, to support QSAR analysis, we developed a high-speed screening method for analyzing the drug-drug interactions of ABCG2. Based on both experimental results and computational QSAR analysis data, we propose a hypothetical mechanism underlying ABC-mediated drug transport and its interaction with drugs.

  15. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana

    OpenAIRE

    Stefanato, Francesca L.; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G.; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-01-01

    Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mut...

  16. Evolution of mal ABC transporter operons in the Thermococcales and Thermotogales

    Directory of Open Access Journals (Sweden)

    Gogarten J Peter

    2008-01-01

    Full Text Available Abstract Background The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry. Results We demonstrate that the two maltose ATP binding cassette (ABC transporter operons now found in Tc. litoralis and P. furiosus (termed mal and mdx genes, respectively are not closely related to one another. The Tc. litoralis and P. furiosus mal genes are most closely related to bacterial mal genes while their respective mdx genes are archaeal. The genes of the two mal operons in Tt. maritima are not related to genes in either of these archaeal operons. They are highly similar to one another and belong to a phylogenetic lineage that includes mal genes from the enteric bacteria. A unique domain of the enteric MalF membrane spanning proteins found also in these Thermotogales MalF homologs supports their relatively close relationship with these enteric proteins. Analyses of genome sequence data from other Thermotogales species, Fervidobacterium nodosum, Thermosipho melanesiensis, Thermotoga petrophila, Thermotoga lettingae, and Thermotoga neapolitana, revealed a third apparent mal operon, absent from the published genome sequence of Tt. maritima strain MSB8. This third operon, mal3, is more closely related to the Thermococcales' bacteria-derived mal genes than are mal1 and mal2. F. nodosum, Ts. melanesiensis, and Tt. lettingae have only one of the mal1-mal2 paralogs. The mal2 operon from an unknown species of Thermotoga appears to

  17. In Vitro Assessment of the Effect of Antiepileptic Drugs on Expression and Function of ABC Transporters and Their Interactions with ABCC2

    Directory of Open Access Journals (Sweden)

    Gurpreet Kaur Grewal

    2017-09-01

    Full Text Available ABC transporters have a significant role in drug disposition and response and various studies have implicated their involvement in epilepsy pharmacoresistance. Since genetic studies till now are inconclusive, we thought of investigating the role of xenobiotics as transcriptional modulators of ABC transporters. Here, we investigated the effect of six antiepileptic drugs (AEDs viz. phenytoin, carbamazepine, valproate, lamotrigine, topiramate and levetiracetam, on the expression and function of ABCB1, ABCC1, ABCC2 and ABCG2 in Caco2 and HepG2 cell lines through real time PCR, western blot and functional activity assays. Further, the interaction of AEDs with maximally induced ABCC2 was studied. Carbamazepine caused a significant induction in expression of ABCB1 and ABCC2 in HepG2 and Caco2 cells, both at the transcript and protein level, together with increased functional activity. Valproate caused a significant increase in the expression and functional activity of ABCB1 in HepG2 only. No significant effect of phenytoin, lamotrigine, topiramate and levetiracetam on the transporters under study was observed in either of the cell lines. We demonstrated the interaction of carbamazepine and valproate with ABCC2 with ATPase and 5,6-carboxyfluorescein inhibition assays. Thus, altered functionality of ABCB1 and ABCC2 can affect the disposition and bioavailability of administered drugs, interfering with AED therapy.

  18. Survey of ABC transporter and metallothionein genes expressions in tall fescue inoculated with Funneliformis intraradices under Nickel toxicity

    Directory of Open Access Journals (Sweden)

    Massomeh Rafiei-Demneh

    2016-09-01

    Full Text Available In plants, there are complex network of transport, chelation, and sequestration processes that functions in maintaining concentrations of essential metal ions in different cellular compartments, thus minimizing the damage caused by entry of non-essential metal ions into the cytosol. In the presence of toxic ones, arbuscular mycorrhizal (AM fungi are able to alleviate metal toxicity in the plant. In this study the effect of an arbuscular mycorrhizal fungi Funneliformis intraradices on growth, Nickel tolerance, and ABC transporter and metallothionein expression in leaves and roots of tall fescue (Festuca arundinacea plants cultivated in Ni polluted soil were evaluated. The fungi infected (M+ and uninfected (M- fescue plants were cultivated in soil under different Ni concentrations (0, 30, 90 and 180 ppm for 3 months. Results demonstrated the positive effect of fungi colonization on the increase in growth and reduction in Ni uptake (90 and 180 ppm and Ni translocation from roots to shoot of tall fescue under Ni stress. The results also demonstrated that the level of ABC transporterand metallothionein transcripts accumulation in roots was considerably higher for both M- and M+ plants compared to the control. Also, M+ plants showed less ABC and MET expression compared to the M- plants. These results demonstrated the importance of mycorrhizal colonization of F. intraradices in reduction of Ni transport from root to shoot of tall fescue which alleviates Ni-induced stress.

  19. Functional Characterization of ABCC Proteins from Trypanosoma cruzi and Their Involvement with Thiol Transport

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    Kelli Monteiro da Costa

    2018-02-01

    Full Text Available Chagas disease is a neglected disease caused by the protozoan Trypanosoma cruzi and affects 8 million people worldwide. The main chemotherapy is based on benznidazole. The efficacy in the treatment depends on factors such as the parasite strain, which may present different sensitivity to treatment. In this context, the expression of ABC transporters has been related to chemotherapy failure. ABC transporters share a well-conserved ABC domain, responsible for ATP binding and hydrolysis, whose the energy released is coupled to transport of molecules through membranes. The most known ABC transporters are ABCB1 and ABCC1, involved in the multidrug resistance phenotype in cancer, given their participation in cellular detoxification. In T. cruzi, 27 ABC genes were identified in the genome. Nonetheless, only four ABC genes were characterized: ABCA3, involved in vesicular trafficking; ABCG1, overexpressed in strains naturally resistant to benznidazole, and P-glycoprotein 1 and 2, whose participation in drug resistance is controversial. Considering P-glycoprotein genes are related to ABCC subfamily in T. cruzi according to the demonstration using BLASTP alignment, we evaluated both ABCB1-like and ABCC-like activities in epimastigote and trypomastigote forms of the Y strain. The transport activities were evaluated by the efflux of the fluorescent dyes Rhodamine 123 and Carboxyfluorescein in a flow cytometer. Results indicated that there was no ABCB1-like activity in both T. cruzi forms. Conversely, results demonstrated ABCC-like activity in both epimastigote and trypomastigote forms of T. cruzi. This activity was inhibited by ABCC transport modulators (probenecid, indomethacin, and MK-571, by ATP-depleting agents (sodium azide and iodoacetic acid and by the thiol-depleting agent N-ethylmaleimide. Additionally, the presence of ABCC-like activity was supported by direct inhibition of the thiol-conjugated compound efflux with indomethacin, characteristic of

  20. A lower isoelectric point increases signal sequence-mediated secretion of recombinant proteins through a bacterial ABC transporter.

    Science.gov (United States)

    Byun, Hyunjong; Park, Jiyeon; Kim, Sun Chang; Ahn, Jung Hoon

    2017-12-01

    Efficient protein production for industrial and academic purposes often involves engineering microorganisms to produce and secrete target proteins into the culture. Pseudomonas fluorescens has a TliDEF ATP-binding cassette transporter, a type I secretion system, which recognizes C-terminal LARD3 signal sequence of thermostable lipase TliA. Many proteins are secreted by TliDEF in vivo when recombined with LARD3, but there are still others that cannot be secreted by TliDEF even when LARD3 is attached. However, the factors that determine whether or not a recombinant protein can be secreted through TliDEF are still unknown. Here, we recombined LARD3 with several proteins and examined their secretion through TliDEF. We found that the proteins secreted via LARD3 are highly negatively charged with highly-acidic isoelectric points (pI) lower than 5.5. Attaching oligo-aspartate to lower the pI of negatively-charged recombinant proteins improved their secretion, and attaching oligo-arginine to negatively-charged proteins blocked their secretion by LARD3. In addition, negatively supercharged green fluorescent protein (GFP) showed improved secretion, whereas positively supercharged GFP did not secrete. These results disclosed that proteins' acidic pI and net negative charge are major factors that determine their secretion through TliDEF. Homology modeling for TliDEF revealed that TliD dimer forms evolutionarily-conserved positively-charged clusters in its pore and substrate entrance site, which also partially explains the pI dependence of the TliDEF-dependent secretions. In conclusion, lowering the isoelectric point improved LARD3-mediated protein secretion, both widening the range of protein targets for efficient production via secretion and signifying an important aspect of ABC transporter-mediated secretions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Active transmembrane drug transport in microgravity: a validation study using an ABC transporter model [v1; ref status: indexed, http://f1000r.es/41n

    Directory of Open Access Journals (Sweden)

    Sergi Vaquer

    2014-08-01

    Full Text Available Abstract Microgravity has been shown to influence the expression of ABC (ATP-Binding Cassette transporters in bacteria, fungi and mammals, but also to modify the activity of certain cellular components with structural and functional similarities to ABC transporters. Changes in activity of ABC transporters could lead to important metabolic disorders and undesired pharmacological effects during spaceflights. However, no current means exist to study the functionality of these transporters in microgravity. To this end, a Vesicular Transport Assay® (Solvo Biotechnology, Hungary was adapted to evaluate multi-drug resistance-associated protein 2 (MRP2 trans-membrane estradiol-17-β-glucuronide (E17βG transport activity, when activated by adenosine-tri-phosphate (ATP during parabolic flights. Simple diffusion, ATP-independent transport and benzbromarone inhibition were also evaluated. A high accuracy engineering system was designed to perform, monitor and synchronize all procedures. Samples were analysed using a validated high sensitivity drug detection protocol. Experiments were performed in microgravity during parabolic flights, and compared to 1g on ground results using identical equipment and procedures in all cases. Our results revealed that sufficient equipment accuracy and analytical sensitivity were reached to detect transport activity in both gravitational conditions. Additionally, transport activity levels of on ground samples were within commercial transport standards, proving the validity of the methods and equipment used. MRP2 net transport activity was significantly reduced in microgravity, so was signal detected in simple diffusion samples. Ultra-structural changes induced by gravitational stress upon vesicle membranes or transporters could explain the current results, although alternative explanations are possible. Further research is needed to provide a conclusive answer in this regard. Nevertheless, the present validated technology

  2. Iowa ABC connections.

    Science.gov (United States)

    2015-06-01

    For several years the Iowa Department of Transportation (DOT), Iowa State University, the Federal Highway Administration, : and several Iowa counties have been working to develop accelerated bridge construction (ABC) concepts, details, and processes....

  3. ABC proteins protect the human body and maintain optimal health.

    Science.gov (United States)

    Ueda, Kazumitsu

    2011-01-01

    Human MDR1, a multi-drug transporter gene, was isolated as the first of the eukaryote ATP Binding Cassette (ABC) proteins from a multidrug-resistant carcinoma cell line in 1986. To date, over 25 years, many ABC proteins have been found to play important physiological roles by transporting hydrophobic compounds. Defects in their functions cause various diseases, indicating that endogenous hydrophobic compounds, as well as water-soluble compounds, are properly transported by transmembrane proteins. MDR1 transports a large number of structurally unrelated drugs and is involved in their pharmacokinetics, and thus is a key factor in drug interaction. ABCA1, an ABC protein, eliminates excess cholesterol in peripheral cells by generating HDL. Because ABCA1 is a key molecule in cholesterol homeostasis, its function and expression are highly regulated. Eukaryote ABC proteins function on the body surface facing the outside and in organ pathways to adapt to the extracellular environment and protect the body to maintain optimal health.

  4. Maltose and maltodextrin utilization by Listeria monocytogenes depend on an inducible ABC transporter which is repressed by glucose.

    Directory of Open Access Journals (Sweden)

    Shubha Gopal

    2010-04-01

    Full Text Available In the environment as well as in the vertebrate intestine, Listeriae have access to complex carbohydrates like maltodextrins. Bacterial exploitation of such compounds requires specific uptake and utilization systems.We could show that Listeria monocytogenes and other Listeria species contain genes/gene products with high homology to the maltodextrin ABC transporter and utilization system of B. subtilis. Mutant construction and growth tests revealed that the L. monocytogenes gene cluster was required for the efficient utilization of maltodextrins as well as maltose. The gene for the ATP binding protein of the transporter was located distant from the cluster. Transcription analyses demonstrated that the system was induced by maltose/maltodextrins and repressed by glucose. Its induction was dependent on a LacI type transcriptional regulator. Repression by glucose was independent of the catabolite control protein CcpA, but was relieved in a mutant defective for Hpr kinase/phosphorylase.The data obtained show that in L. monocytogenes the uptake of maltodextrin and, in contrast to B. subtilis, also maltose is exclusively mediated by an ABC transporter. Furthermore, the results suggest that glucose repression of the uptake system possibly is by inducer exclusion, a mechanism not described so far in this organism.

  5. Structure and function of the universal stress protein TeaD and its role in regulating the ectoine transporter TeaABC of Halomonas elongata DSM 2581(T).

    Science.gov (United States)

    Schweikhard, Eva S; Kuhlmann, Sonja I; Kunte, Hans-Jörg; Grammann, Katrin; Ziegler, Christine M

    2010-03-16

    The halophilic bacterium Halomonas elongata takes up the compatible solute ectoine via the osmoregulated TRAP transporter TeaABC. A fourth orf (teaD) is located adjacent to the teaABC locus that encodes a putative universal stress protein (USP). By RT-PCR experiments we proved a cotranscription of teaD along with teaABC. Deletion of teaD resulted in an enhanced uptake for ectoine by the transporter TeaABC and hence a negative activity regulation of TeaABC by TeaD. A transcriptional regulation via DNA binding could be excluded. ATP binding to native TeaD was shown by HPLC, and the crystal structure of TeaD was solved in complex with ATP to a resolution of 1.9 A by molecular replacement. TeaD forms a dimer-dimer complex with one ATP molecule bound to each monomer, which has a Rossmann-like alpha/beta overall fold. Our results reveal an ATP-dependent oligomerization of TeaD, which might have a functional role in the regulatory mechanism of TeaD. USP-encoding orfs, which are located adjacent to genes encoding for TeaABC homologues, could be identified in several other organisms, and their physiological role in balancing the internal cellular ectoine pool is discussed.

  6. The abcEDCBA-Encoded ABC Transporter and the virB Operon-Encoded Type IV Secretion System of Brucella ovis Are Critical for Intracellular Trafficking and Survival in Ovine Monocyte-Derived Macrophages.

    Directory of Open Access Journals (Sweden)

    Auricelio A Macedo

    Full Text Available Brucella ovis infection is associated with epididymitis, orchitis and infertility in rams. Most of the information available on B. ovis and host cell interaction has been generated using murine macrophages or epithelial cell lines, but the interaction between B. ovis and primary ovine macrophages has not been studied. The aim of this study was to evaluate the role of the B. ovis abcEDCBA-encoded ABC transporter and the virB operon-encoded Type IV Secretion System (T4SS during intracellular survival of B. ovis in ovine peripheral blood monocyte-derived macrophages. ΔabcBA and ΔvirB2 mutant strains were unable to survive in the intracellular environment when compared to the WT B. ovis at 48 hours post infection (hpi. In addition, these mutant strains cannot exclude the lysosomal marker LAMP1 from its vacuolar membrane, and their vacuoles do not acquire the endoplasmic reticulum marker calreticulin, which takes place in the WT B. ovis containing vacuole. Higher levels of nitric oxide production were observed in macrophages infected with WT B. ovis at 48 hpi when compared to macrophages infected with the ΔabcBA or ΔvirB2 mutant strains. Conversely, higher levels of reactive oxygen species were detected in macrophages infected with the ΔabcBA or ΔvirB2 mutant strains at 48 hpi when compared to macrophages infected with the WT strain. Our results demonstrate that B. ovis is able to persist and multiply in ovine macrophages, while ΔabcBA and ΔvirB2 mutations prevent intracellular multiplication, favor phagolysosome fusion, and impair maturation of the B. ovis vacuole towards an endoplasmic reticulum-derived compartment.

  7. ATP binding and hydrolysis disrupt the high-affinity interaction between the heme ABC transporter HmuUV and its cognate substrate-binding protein.

    Science.gov (United States)

    Qasem-Abdullah, Hiba; Perach, Michal; Livnat-Levanon, Nurit; Lewinson, Oded

    2017-09-01

    Using the energy of ATP hydrolysis, ABC transporters catalyze the trans-membrane transport of molecules. In bacteria, these transporters partner with a high-affinity substrate-binding protein (SBP) to import essential micronutrients. ATP binding by Type I ABC transporters (importers of amino acids, sugars, peptides, and small ions) stabilizes the interaction between the transporter and the SBP, thus allowing transfer of the substrate from the latter to the former. In Type II ABC transporters (importers of trace elements, e.g. vitamin B 12 , heme, and iron-siderophores) the role of ATP remains debatable. Here we studied the interaction between the Yersinia pestis ABC heme importer (HmuUV) and its partner substrate-binding protein (HmuT). Using real-time surface plasmon resonance experiments and interaction studies in membrane vesicles, we find that in the absence of ATP the transporter and the SBP tightly bind. Substrate in excess inhibits this interaction, and ATP binding by the transporter completely abolishes it. To release the stable docked SBP from the transporter hydrolysis of ATP is required. Based on these results we propose a mechanism for heme acquisition by HmuUV-T where the substrate-loaded SBP docks to the nucleotide-free outward-facing conformation of the transporter. ATP binding leads to formation of an occluded state with the substrate trapped in the trans-membrane translocation cavity. Subsequent ATP hydrolysis leads to substrate delivery to the cytoplasm, release of the SBP, and resetting of the system. We propose that other Type II ABC transporters likely share the fundamentals of this mechanism. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana.

    Science.gov (United States)

    Stefanato, Francesca L; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-05-01

    Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mutants. A B. cinerea strain lacking functional BcatrB is more sensitive to camalexin in vitro and less virulent on wild-type plants, but is still fully virulent on camalexin-deficient mutants. Pre-treatment of A. thaliana with UV-C leads to increased camalexin accumulation and substantial resistance to B. cinerea. UV-C-induced resistance was not seen in the camalexin-deficient mutants cyp79B2/B3, cyp71A13, pad3 or pad2, and was strongly reduced in ups1. Here we demonstrate that an ABC transporter is a virulence factor that increases tolerance of the pathogen towards a phytoalexin, and the complete restoration of virulence on host plants lacking this phytoalexin.

  9. TetAB46, a predicted heterodimeric ABC transporter conferring tetracycline resistance in Streptococcus australis isolated from the oral cavity.

    Science.gov (United States)

    Warburton, Philip J; Ciric, Lena; Lerner, Avigdor; Seville, Lorna A; Roberts, Adam P; Mullany, Peter; Allan, Elaine

    2013-01-01

    To identify the genes responsible for tetracycline resistance in a strain of Streptococcus australis isolated from pooled saliva from healthy volunteers in France. S. australis is a viridans Streptococcus, originally isolated from the oral cavity of children in Australia, and subsequently reported in the lungs of cystic fibrosis patients and as a cause of invasive disease in an elderly patient. Agar containing 2 mg/L tetracycline was used for the isolation of tetracycline-resistant organisms. A genomic library in Escherichia coli was used to isolate the tetracycline resistance determinant. In-frame deletions and chromosomal repair were used to confirm function. Antibiotic susceptibility was determined by agar dilution and disc diffusion assay. The tetracycline resistance determinant from S. australis FRStet12 was isolated from a genomic library in E. coli and DNA sequencing showed two open reading frames predicted to encode proteins with similarity to multidrug resistance-type ABC transporters. Both genes were required for tetracycline resistance (to both the naturally occurring and semi-synthetic tetracyclines) and they were designated tetAB(46). This is the first report of a predicted ABC transporter conferring tetracycline resistance in a member of the oral microbiota.

  10. Investigating the dynamic nature of the ABC transporters: ABCB1 and MsbA as examples for the potential synergies of MD theory and EPR applications.

    Science.gov (United States)

    Stockner, Thomas; Mullen, Anna; MacMillan, Fraser

    2015-10-01

    ABC transporters are primary active transporters found in all kingdoms of life. Human multidrug resistance transporter ABCB1, or P-glycoprotein, has an extremely broad substrate spectrum and confers resistance against chemotherapy drug treatment in cancer cells. The bacterial ABC transporter MsbA is a lipid A flippase and a homolog to the human ABCB1 transporter, with which it partially shares its substrate spectrum. Crystal structures of MsbA and ABCB1 have been solved in multiple conformations, providing a glimpse into the possible conformational changes the transporter could be going through during the transport cycle. Crystal structures are inherently static, while a dynamic picture of the transporter in motion is needed for a complete understanding of transporter function. Molecular dynamics (MD) simulations and electron paramagnetic resonance (EPR) spectroscopy can provide structural information on ABC transporters, but the strength of these two methods lies in the potential to characterise the dynamic regime of these transporters. Information from the two methods is quite complementary. MD simulations provide an all atom dynamic picture of the time evolution of the molecular system, though with a narrow time window. EPR spectroscopy can probe structural, environmental and dynamic properties of the transporter in several time regimes, but only through the attachment sites of an exogenous spin label. In this review the synergistic effects that can be achieved by combining the two methods are highlighted, and a brief methodological background is also presented. © 2015 Authors; published by Portland Press Limited.

  11. A burst of ABC genes in the genome of the polyphagous spider mite Tetranychus urticae

    Science.gov (United States)

    2013-01-01

    Background The ABC (ATP-binding cassette) gene superfamily is widespread across all living species. The majority of ABC genes encode ABC transporters, which are membrane-spanning proteins capable of transferring substrates across biological membranes by hydrolyzing ATP. Although ABC transporters have often been associated with resistance to drugs and toxic compounds, within the Arthropoda ABC gene families have only been characterized in detail in several insects and a crustacean. In this study, we report a genome-wide survey and expression analysis of the ABC gene superfamily in the spider mite, Tetranychus urticae, a chelicerate ~ 450 million years diverged from other Arthropod lineages. T. urticae is a major agricultural pest, and is among of the most polyphagous arthropod herbivores known. The species resists a staggering array of toxic plant secondary metabolites, and has developed resistance to all major classes of pesticides in use for its control. Results We identified 103 ABC genes in the T. urticae genome, the highest number discovered in a metazoan species to date. Within the T. urticae ABC gene set, all members of the eight currently described subfamilies (A to H) were detected. A phylogenetic analysis revealed that the high number of ABC genes in T. urticae is due primarily to lineage-specific expansions of ABC genes within the ABCC, ABCG and ABCH subfamilies. In particular, the ABCC subfamily harbors the highest number of T. urticae ABC genes (39). In a comparative genomic analysis, we found clear orthologous relationships between a subset of T. urticae ABC proteins and ABC proteins in both vertebrates and invertebrates known to be involved in fundamental cellular processes. These included members of the ABCB-half transporters, and the ABCD, ABCE and ABCF families. Furthermore, one-to-one orthologues could be distinguished between T. urticae proteins and human ABCC10, ABCG5 and ABCG8, the Drosophila melanogaster sulfonylurea receptor and ecdysone

  12. Severities of transportation accidents involving large packages

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, A.W.; Foley, J.T. Jr.; Hartman, W.F.; Larson, D.W.

    1978-05-01

    The study was undertaken to define in a quantitative nonjudgmental technical manner the abnormal environments to which a large package (total weight over 2 tons) would be subjected as the result of a transportation accident. Because of this package weight, air shipment was not considered as a normal transportation mode and was not included in the study. The abnormal transportation environments for shipment by motor carrier and train were determined and quantified. In all cases the package was assumed to be transported on an open flat-bed truck or an open flat-bed railcar. In an earlier study, SLA-74-0001, the small-package environments were investigated. A third transportation study, related to the abnormal environment involving waterways transportation, is now under way at Sandia Laboratories and should complete the description of abnormal transportation environments. Five abnormal environments were defined and investigated, i.e., fire, impact, crush, immersion, and puncture. The primary interest of the study was directed toward the type of large package used to transport radioactive materials; however, the findings are not limited to this type of package but can be applied to a much larger class of material shipping containers.

  13. Severities of transportation accidents involving large packages

    International Nuclear Information System (INIS)

    Dennis, A.W.; Foley, J.T. Jr.; Hartman, W.F.; Larson, D.W.

    1978-05-01

    The study was undertaken to define in a quantitative nonjudgmental technical manner the abnormal environments to which a large package (total weight over 2 tons) would be subjected as the result of a transportation accident. Because of this package weight, air shipment was not considered as a normal transportation mode and was not included in the study. The abnormal transportation environments for shipment by motor carrier and train were determined and quantified. In all cases the package was assumed to be transported on an open flat-bed truck or an open flat-bed railcar. In an earlier study, SLA-74-0001, the small-package environments were investigated. A third transportation study, related to the abnormal environment involving waterways transportation, is now under way at Sandia Laboratories and should complete the description of abnormal transportation environments. Five abnormal environments were defined and investigated, i.e., fire, impact, crush, immersion, and puncture. The primary interest of the study was directed toward the type of large package used to transport radioactive materials; however, the findings are not limited to this type of package but can be applied to a much larger class of material shipping containers

  14. Diversity and evolution of ABC proteins in mycorrhiza-forming fungi.

    Science.gov (United States)

    Kovalchuk, Andriy; Kohler, Annegret; Martin, Francis; Asiegbu, Fred O

    2015-12-28

    Transporter proteins are predicted to have an important role in the mycorrhizal symbiosis, due to the fact that this type of an interaction between plants and fungi requires a continuous nutrient and signalling exchange. ABC transporters are one of the large groups of transporter proteins found both in plants and in fungi. The crucial role of plant ABC transporters in the formation of the mycorrhizal symbiosis has been demonstrated recently. Some of the fungal ABC transporter-encoding genes are also induced during the mycorrhiza formation. However, no experimental evidences of the direct involvement of fungal ABC transporters in this process are available so far. To facilitate the identification of fungal ABC proteins with a potential role in the establishment of the mycorrhizal symbiosis, we have performed an inventory of the ABC protein-encoding genes in the genomes of 25 species of mycorrhiza-forming fungi. We have identified, manually annotated and curated more than 1300 gene models of putative ABC protein-encoding genes. Out of those, more than 1000 models are predicted to encode functional proteins, whereas about 300 models represent gene fragments or putative pseudogenes. We have also performed the phylogenetic analysis of the identified sequences. The sets of ABC proteins in the mycorrhiza-forming species were compared to the related saprotrophic or plant-pathogenic fungal species. Our results demonstrate the high diversity of ABC genes in the genomes of mycorrhiza-forming fungi. Via comparison of transcriptomics data from different species, we have identified candidate groups of ABC transporters that might have a role in the process of the mycorrhiza formation. Results of our inventory will facilitate the identification of fungal transporters with a role in the mycorrhiza formation. We also provide the first data on ABC protein-coding genes for the phylum Glomeromycota and for orders Pezizales, Atheliales, Cantharellales and Sebacinales, contributing to

  15. Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo.

    Directory of Open Access Journals (Sweden)

    Suneeta Chimalapati

    Full Text Available Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt, deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection.

  16. Identification of the minimal region in lipase ABC transporter recognition domain of Pseudomonas fluorescens for secretion and fluorescence of green fluorescent protein

    Directory of Open Access Journals (Sweden)

    Park Yeonwoo

    2012-05-01

    Full Text Available Abstract Background TliA is a thermostable lipase secreted by the type 1 secretion system (T1SS of Pseudomonas fluorescens. The secretion is promoted by its secretion/chaperone domain located near the C-terminus, which is composed mainly of four Repeat-in-Toxin (RTX repeats. In order to identify the minimal region of TliA responsible for its secretion, five different copies of the secretion/chaperone domain, each involving truncated N-terminal residues and a common C-terminus, were acquired and named as lipase ABC transporter recognition domains (LARDs. Each LARD was fused to epidermal growth factor (EGF or green fluorescent protein (GFP, and the secretion of EGF-LARD or GFP-LARD fusion proteins was assessed in Escherichia coli with ABC transporter. Results Among the fusion proteins, GFP or EGF with 105-residue LARD3 was most efficiently secreted. In addition, GFP-LARD3 emitted wild type GFP fluorescence. Structurally, LARD3 had the 4 RTX repeats exposed at the N-terminus, while other LARDs had additional residues prior to them or missed some of the RTX repeats. LARD3 was both necessary and sufficient for efficient secretion and maintenance of GFP fluorescence in E. coli, which was also confirmed in P. fluorescens and P. fluorescens ▵tliA, a knock-out mutant of tliA. Conclusion LARD3 was a potent secretion signal in T1SS for its fusion flanking RTX motif, which enhanced secretion and preserved the fluorescence of GFP. LARD3-mediated secretion in E. coli or P. fluorescens will enable the development of enhanced protein manufacturing factory and recombinant microbe secreting protein of interest in situ.

  17. The Schizosaccharomyces pombe mam1 gene encodes an ABC transporter mediating secretion of M-factor

    DEFF Research Database (Denmark)

    Christensen, P U; Davey, William John; Nielsen, O

    1997-01-01

    In the fission yeast Schizosaccharomyces pombe, cells of opposite mating type communicate via diffusible peptide pheromones prior to mating. We have cloned the S. pombe mam1 gene, which encodes a 1336-amino acid protein belonging to the ATP-binding cassette (ABC) superfamily. The mam1 gene is only...... expressed in M cells and the gene product is responsible for the secretion of the mating pheromone. M-factor, a nonapeptide that is S-farnesylated and carboxy-methylated on its C-terminal cysteine residue. The predicted Mam1 protein is highly homologous to mammalian multiple drug-resistance proteins...

  18. Secondary metabolites inhibiting ABC transporters and reversing resistance of cancer cells and fungi to cytotoxic and antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Michael eWink

    2012-04-01

    Full Text Available Fungal, bacterial and cancer cells can develop resistance against antifungal, antibacterial or anticancer agents. Mechanisms of resistance are complex and often multifactorial. Mechanisms include: 1. Activation of ABC transporters, such as P-gp, which pump out lipophilic compounds that have entered a cell, 2. Activation of cytochrome p450 oxidases which can oxidise lipophilic agents to make them more hydrophilic and accessible for conjugation reaction with glucuronic acid, sulphate or amino acids, and 3. Activation of glutathione transferase, which can conjugate xenobiotics. This review summarises the evidence that secondary metabolites of plants, such as alkaloids, phenolics and terpenoids can interfere with ABC transporters in cancer cells, parasites, bacteria and fungi. Among the active natural products several lipophilic terpenoids ( monoterpenes, diterpenes, triterpenes (including saponins, steroids (including cardiac glycosides and tetraterpenes but also some alkaloids (isoquinoline, protoberberine, quinoline, indole, monoterpene indole, and steroidal alkaloids function probably as competitive inhibitors of P-gp, MRP1 and BCRP in cancer cells, or efflux pumps in bacteria (NorA and fungi. More polar phenolics (phenolic acids, flavonoids, catechins, chalcones, xanthones, stilbenes, anthocyanins, tannins, anthraquinones, and naphthoquinones directly inhibit proteins forming several hydrogen and ionic bonds and thus disturbing the 3D structure of the transporters. The natural products may be interesting in medicine or agriculture as they can enhance the activity of active chemotherapeutics or pesticides or even reverse MDR, at least partially, of adapted and resistant cells. If these secondary metabolites are applied in combination with a cytotoxic or antimicrobial agent, they may reverse resistance in a synergistic fashion.

  19. The Crystal Structure of the YknZ Extracellular Domain of ABC Transporter YknWXYZ from Bacillus amyloliquefaciens.

    Directory of Open Access Journals (Sweden)

    Yongbin Xu

    Full Text Available Bacillus possesses the peptide toxin Sporulation-Delaying Protein (SDP, which can kill cells within a biofilm to support continued growth, thereby delaying the onset of biofilm sporulation. The four-component transporter YknWXYZ acts as a major SDP efflux pump to protect cells against the endogenous SDP toxin, for which YknYZ is a non-canonical ATP-binding cassette (ABC-type transporter. YknYZ consists of the following two components: (1 an individual protein (YknY and (2 a respective permease (YknZ. To date, the crystal structure, molecular function, and mechanism of action of the integral membrane protein YknZ remain to be elucidated. In this study, to characterize the structural and biochemical roles of YknZ in the functional assembly of YknWXYZ, we predicted and overexpressed the YknZ extracellular domain. We determined the crystal structure of B. amyloliquefaciens YknZ at a resolution of 2.0 Å. The structure revealed that the YknZ extracellular region exhibits significant structural similarity with the MacB periplasmic domain, which is a non-canonical ABC-type transporter in the tripartite macrolide-specific efflux pump in Gram-negative bacteria. We also found that the YknZ extracellular domain can directly bind to an extracellular component of YknX. This structural and biochemical study provides insights into the assembly of YknWXYZ, which may be relevant to understanding cannibalistic peptide toxin resistance in Bacillus and controlling bacterial growth.

  20. Iowa ABC connections : [tech transfer summary].

    Science.gov (United States)

    2015-06-01

    The Iowa Department of Transportation (DOT) and other organizations have : been developing accelerated bridge construction (ABC) concepts, details, and : processes, and Iowa has come to be viewed as a national leader in the area of : ABC. However, th...

  1. The expression of superoxide dismutase (SOD) and a putative ABC transporter permease is inversely correlated during biofilm formation in Listeria monocytogenes 4b G

    Science.gov (United States)

    Little is known about the molecular basis of biofilm formation in Listeria monocytogenes. The superoxide dismutase (SOD) of the deletion mutant of lm.G_1771 gene, which encodes for a putative ABC_transporter permease, is highly expressed in biofilm. In this study, the sod gene deletion mutant delta ...

  2. X-linked adrenoleukodystrophy: very long-chain fatty acid metabolism, ABC half-transporters and the complicated route to treatment

    NARCIS (Netherlands)

    Kemp, Stephan; Wanders, Ronald J. A.

    2007-01-01

    X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene that encodes a peroxisomal membrane located ABC half-transporter named ALDP. Mutations in ALDP result in elevated levels of very long-chain fatty acids (VLCFA) and reduced VLCFA beta-oxidation in peroxisomes. The

  3. Pharmacological activation of LXR in utero directly influences ABC transporter expression and function in mice but does not affect adult cholesterol metabolism

    NARCIS (Netherlands)

    van Straten, E. M. E.; Huijkman, N. C. A.; Baller, J. F. W.; Kuipers, F.; Plosch, T.

    2008-01-01

    van Straten EM, Huijkman NC, Baller JF, Kuipers F, Plosch T. Pharmacological activation of LXR in utero directly influences ABC transporter expression and function in mice but does not affect adult cholesterol metabolism. Am J Physiol Endocrinol Metab 295: E1341-E1348, 2008. First published October

  4. Salinomycin overcomes ABC transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like KG-1a cells

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Dominik [Research Group Molecular Neuro-Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Daniel, Volker; Sadeghi, Mahmoud; Opelz, Gerhard [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Naujokat, Cord, E-mail: cord.naujokat@med.uni-heidelberg.de [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany)

    2010-04-16

    Leukemia stem cells are known to exhibit multidrug resistance by expression of ATP-binding cassette (ABC) transporters which constitute transmembrane proteins capable of exporting a wide variety of chemotherapeutic drugs from the cytosol. We show here that human promyeloblastic leukemia KG-1a cells exposed to the histone deacetylase inhibitor phenylbutyrate resemble many characteristics of leukemia stem cells, including expression of functional ABC transporters such as P-glycoprotein, BCRP and MRP8. Consequently, KG-1a cells display resistance to the induction of apoptosis by various chemotherapeutic drugs. Resistance to apoptosis induction by chemotherapeutic drugs can be reversed by cyclosporine A, which effectively inhibits the activity of P-glycoprotein and BCRP, thus demonstrating ABC transporter-mediated drug resistance in KG-1a cells. However, KG-1a are highly sensitive to apoptosis induction by salinomycin, a polyether ionophore antibiotic that has recently been shown to kill human breast cancer stem cell-like cells and to induce apoptosis in human cancer cells displaying multiple mechanisms of drug and apoptosis resistance. Whereas KG-1a cells can be adapted to proliferate in the presence of apoptosis-inducing concentrations of bortezomib and doxorubicin, salinomycin does not permit long-term adaptation of the cells to apoptosis-inducing concentrations. Thus, salinomycin should be regarded as a novel and effective agent for the elimination of leukemia stem cells and other tumor cells exhibiting ABC transporter-mediated multidrug resistance.

  5. Conservation of targeting but divergence in function and quality control of peroxisomal ABC transporters: an analysis using cross-kingdom expression

    NARCIS (Netherlands)

    Zhang, Xuebin; de Marcos Lousa, Carine; Schutte-Lensink, Nellie; Ofman, Rob; Wanders, Ronald J.; Baldwin, Stephen A.; Baker, Alison; Kemp, Stephan; Theodoulou, Frederica L.

    2011-01-01

    ABC (ATP-binding cassette) subfamily D transporters are found in all eukaryotic kingdoms and are known to play essential roles in mammals and plants; however, their number, organization and physiological contexts differ. Via cross-kingdom expression experiments, we have explored the conservation of

  6. Molecular insights into the mechanism of ATP-hydrolysis by the NBD of the ABC-transporter HlyB.

    Science.gov (United States)

    Hanekop, N; Zaitseva, J; Jenewein, S; Holland, I B; Schmitt, L

    2006-02-13

    The ABC-transporter HlyB is a central element of the Type I protein secretion machinery, dedicated to export the E. coli toxin HlyA in a single step across the two membranes of the cell envelope. Here, we discuss recent insights into the structure and the mechanism of ATP-hydrolysis by the NBD of HlyB. Combining structural and biochemical data, we have suggested that substrate-assisted catalysis (SAC), but not general base catalysis, is responsible for ATP-hydrolysis in this NBD and might also operate in other NBDs. Finally, the implications and advantages of SAC are discussed in the context of ATP-induced dimerization of the NBDs.

  7. Antagonistic changes in sensitivity to antifungal drugs by mutations of an important ABC transporter gene in a fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Wenjun Guan

    2010-06-01

    Full Text Available Fungal pathogens can be lethal, especially among immunocompromised populations, such as patients with AIDS and recipients of tissue transplantation or chemotherapy. Prolonged usage of antifungal reagents can lead to drug resistance and treatment failure. Understanding mechanisms that underlie drug resistance by pathogenic microorganisms is thus vital for dealing with this emerging issue. In this study, we show that dramatic sequence changes in PDR5, an ABC (ATP-binding cassette efflux transporter protein gene in an opportunistic fungal pathogen, caused the organism to become hypersensitive to azole, a widely used antifungal drug. Surprisingly, the same mutations conferred growth advantages to the organism on polyenes, which are also commonly used antimycotics. Our results indicate that Pdr5p might be important for ergosterol homeostasis. The observed remarkable sequence divergence in the PDR5 gene in yeast strain YJM789 may represent an interesting case of adaptive loss of gene function with significant clinical implications.

  8. The Schizosaccharomyces pombe mam1 gene encodes an ABC transporter mediating secretion of M-factor

    DEFF Research Database (Denmark)

    Christensen, P U; Davey, William John; Nielsen, O

    1997-01-01

    In the fission yeast Schizosaccharomyces pombe, cells of opposite mating type communicate via diffusible peptide pheromones prior to mating. We have cloned the S. pombe mam1 gene, which encodes a 1336-amino acid protein belonging to the ATP-binding cassette (ABC) superfamily. The mam1 gene is only...... expressed in M cells and the gene product is responsible for the secretion of the mating pheromone. M-factor, a nonapeptide that is S-farnesylated and carboxy-methylated on its C-terminal cysteine residue. The predicted Mam1 protein is highly homologous to mammalian multiple drug-resistance proteins...... and to the Saccharomyces cerevisiae STE6 gene product, which mediates export of a-factor mating pheromone. We show that STE6 can also mediate secretion of M-factor in S. pombe....

  9. Backbone NMR resonance assignments of the nucleotide binding domain of the ABC multidrug transporter LmrA from Lactococcus lactis in its ADP-bound state.

    Science.gov (United States)

    Hellmich, Ute A; Duchardt-Ferner, Elke; Glaubitz, Clemens; Wöhnert, Jens

    2012-04-01

    LmrA from Lactococcus lactis is a multidrug transporter and a member of the ATP binding cassette (ABC) transporter family. ABC transporters consist of a transmembrane domain (TMD) and a nucleotide binding domain (NBD). The NBD contains the highly conserved signature motifs of this transporter superfamily. In the case of LmrA, the TMD and the NBD are expressed as a single polypeptide. LmrA catalyzes the extrusion of hydrophobic compounds including antibiotics from the cell membrane at the expense of ATP hydrolysis. ATP binds to the NBD, where binding and hydrolysis induce conformational changes that lead to the extrusion of the substrate via the TMD. Here, we report the (1)H, (13)C and (15)N backbone chemical shift assignments of the isolated 263 amino acid containing NBD of LmrA in its ADP bound state.

  10. Professionsbachelorens ABC

    DEFF Research Database (Denmark)

    Svendsen, Christian Bundgaard

    2008-01-01

    På baggrund af Lars-Henrik Schmidts "Sociale ABC" og Bloom og Dreyfus' taksonomier gives der et teoretiske bud på professionsbachelorbegrebet......På baggrund af Lars-Henrik Schmidts "Sociale ABC" og Bloom og Dreyfus' taksonomier gives der et teoretiske bud på professionsbachelorbegrebet...

  11. Validation of inhibitors of an ABC transporter required to transport lipopolysaccharide to the cell surface in Escherichia coli

    Science.gov (United States)

    Sherman, David J.; Okuda, Suguru; Denny, William A.; Kahne, Daniel

    2013-01-01

    The presence of lipopolysaccharide (LPS) in the outer leaflet of the outer membrane (OM) of Gram-negative bacteria creates a permeability barrier that prevents the entry of most currently available antibiotics. The seven lipopolysaccharide transport (Lpt) proteins involved in transporting and assembling this glycolipid are essential for growth and division in Escherichia coli; therefore, inhibiting their functions leads to cell death. LptB, the ATPase that provides energy for LPS transport and assembly, forms a complex with three other inner membrane (IM) components, LptC, F, and G. We demonstrate that inhibitors of pure LptB can also inhibit the full IM complex, LptBFGC, purified in detergent. We also compare inhibition of LptB and the LptBFGC complex with the antibiotic activity of these compounds. Our long-term goal is to develop tools to study inhibitors of LPS biogenesis that could serve as potentiators by disrupting the OM permeability barrier, facilitating entry of clinically used antibiotics not normally used to treat Gram-negative infections, or that can serve as antibiotics themselves. PMID:23665139

  12. Functional characterization of the Bradyrhizobium japonicum modA and modB genes involved in molybdenum transport.

    Science.gov (United States)

    Delgado, María J; Tresierra-Ayala, Alvaro; Talbi, Chouhra; Bedmar, Eulogio J

    2006-01-01

    A modABC gene cluster that encodes an ABC-type, high-affinity molybdate transporter from Bradyrhizobium japonicum has been isolated and characterized. B. japonicum modA and modB mutant strains were unable to grow aerobically or anaerobically with nitrate as nitrogen source or as respiratory substrate, respectively, and lacked nitrate reductase activity. The nitrogen-fixing ability of the mod mutants in symbiotic association with soybean plants grown in a Mo-deficient mineral solution was severely impaired. Addition of molybdate to the bacterial growth medium or to the plant mineral solution fully restored the wild-type phenotype. Because the amount of molybdate required for suppression of the mutant phenotype either under free-living or under symbiotic conditions was dependent on sulphate concentration, it is likely that a sulphate transporter is also involved in Mo uptake in B. japonicum. The promoter region of the modABC genes has been characterized by primer extension. Reverse transcription and expression of a transcriptional fusion, P(modA)-lacZ, was detected only in a B. japonicum modA mutant grown in a medium without molybdate supplementation. These findings indicate that transcription of the B. japonicum modABC genes is repressed by molybdate.

  13. The multidrug ABC transporter BmrC/BmrD of Bacillus subtilis is regulated via a ribosome-mediated transcriptional attenuation mechanism

    OpenAIRE

    Reilman, E.; Mars, R. A. T.; van Dijl, J. M.; Denham, Emma

    2014-01-01

    Expression of particular drug transporters in response to antibiotic pressure is a critical element in the development of bacterial multidrug resistance, and represents a serious concern for human health. To obtain a better understanding of underlying regulatory mechanisms, we have dissected the transcriptional activation of the ATP-binding cassette (ABC) transporter BmrC/BmrD of the Gram-positive model bacterium Bacillus subtilis. By using promoter-GFP fusions and live cell array technology,...

  14. The ABC transporter MalFGK2 sequesters the MalT transcription factor at the membrane in the absence of cognate substrate

    OpenAIRE

    Richet, Evelyne; Davidson, Amy L.; Joly, Nicolas

    2012-01-01

    MalK, the cytoplasmic component of the maltose ABC transporter from Escherichia coli is known to control negatively the activity of MalT, the activator of the maltose regulon, through complex formation. Here we further investigate this regulatory process by monitoring MalT activity and performing fluorescence microscopy analyses under various conditions. We establish that, under physiological conditions, the molecular entity that interacts with MalT is not free MalK, but the maltose transport...

  15. Genome-wide comparative analysis of ABC systems in the Bdellovibrio-and-like organisms.

    Science.gov (United States)

    Li, Nan; Chen, Huan; Williams, Henry N

    2015-05-10

    Bdellovibrio-and-like organisms (BALOs) are gram-negative, predatory bacteria with wide variations in genome sizes and GC content and ecological habitats. The ATP-binding cassette (ABC) systems have been identified in several prokaryotes, fungi and plants and have a role in transport of materials in and out of cells and in cellular processes. However, knowledge of the ABC systems of BALOs remains obscure. A total of 269 putative ABC proteins were identified in BALOs. The genes encoding these ABC systems occupy nearly 1.3% of the gene content in freshwater Bdellovibrio strains and about 0.7% in their saltwater counterparts. The proteins found belong to 25 ABC system families based on their structural characteristics and functions. Among these, 16 families function as importers, 6 as exporters and 3 are involved in various cellular processes. Eight of these 25 ABC system families were deduced to be the core set of ABC systems conserved in all BALOs. All Bacteriovorax strains have 28 or less ABC systems. On the contrary, the freshwater Bdellovibrio strains have more ABC systems, typically around 51. In the genome of Bdellovibrio exovorus JSS (CP003537.1), 53 putative ABC systems were detected, representing the highest number among all the BALO genomes examined in this study. Unexpected high numbers of ABC systems involved in cellular processes were found in all BALOs. Phylogenetic analysis suggests that the majority of ABC proteins can be assigned into many separate families with high bootstrap supports (>50%). In this study, a general framework of sequence-structure-function connections for the ABC systems in BALOs was revealed providing novel insights for future investigations. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. 9-Deazapurines as Broad-Spectrum Inhibitors of the ABC Transport Proteins P-Glycoprotein, Multidrug Resistance-Associated Protein 1, and Breast Cancer Resistance Protein.

    Science.gov (United States)

    Stefan, Katja; Schmitt, Sven Marcel; Wiese, Michael

    2017-11-09

    P-Glycoprotein (P-gp, ABCB1), multidrug resistance-associated protein 1 (MRP1, ABCC1), and breast cancer resistance protein (BCRP, ABCG2) are the three major ABC transport proteins conferring resistance to many structurally diverse anticancer agents, leading to the phenomenon called multidrug resistance (MDR). Much effort has been put into the development of clinically useful compounds to reverse MDR. Broad-spectrum inhibitors of ABC transport proteins can be of great use in cancers that simultaneously coexpress two or three transporters. In this work, we continued our effort to generate new, potent, nontoxic, and multiply effective inhibitors of the three major ABC transporters. The best compound was active in a very low micromolar concentration range against all three transporters and restored sensitivity toward daunorubicin (P-gp and MRP1) and SN-38 (BCRP) in A2780/ADR (P-gp), H69AR (MRP1), and MDCK II BCRP (BCRP) cells. Additionally, the compound is a noncompetitive inhibitor of daunorubicin (MRP1), calcein AM (P-gp), and pheophorbide A (BCRP) transport.

  17. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    NARCIS (Netherlands)

    Bhattacharjee, S.; Opstal, van E.J.; Alink, G.M.; Marcelis, A.T.M.; Zuilhof, H.; Rietjens, I.M.C.M.

    2013-01-01

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles

  18. YehZYXW of Escherichia coli Is a Low-Affinity, Non-Osmoregulatory Betaine-Specific ABC Transporter.

    Science.gov (United States)

    Lang, Shenhui; Cressatti, Marisa; Mendoza, Kris E; Coumoundouros, Chelsea N; Plater, Samantha M; Culham, Doreen E; Kimber, Matthew S; Wood, Janet M

    2015-09-22

    Transporter-mediated osmolyte accumulation stimulates the growth of Escherichia coli in high-osmolality environments. YehZYXW was predicted to be an osmoregulatory transporter because (1) osmotic and stationary phase induction of yehZYXW is mediated by RpoS, (2) the Yeh proteins are homologous to the components of known osmoregulatory ABC transporters (e.g., ProU of E. coli), and (3) YehZ models based on the structures of periplasmic betaine-binding proteins suggested that YehZ retains key betaine-binding residues. The betaines choline-O-sulfate, glycine betaine, and dimethylsulfoniopropionate bound YehZ and ProX with millimolar and micromolar affinities, respectively, as determined by equilibrium dialysis and isothermal titration calorimetry. The crystal structure of the YehZ apoprotein, determined at 1.5 Å resolution (PDB ID: 4WEP ), confirmed its similarity to other betaine-binding proteins. Small and nonpolar residues in the hinge region of YehZ (e.g., Gly223) pack more closely than the corresponding residues in ProX, stabilizing the apoprotein. Betaines bound YehZ-Gly223Ser an order of magnitude more tightly than YehZ, suggesting that weak substrate binding in YehZ is at least partially due to apo state stabilization. Neither ProX nor YehZ bound proline. Assays based on osmoprotection or proline auxotrophy failed to detect YehZYXW-mediated uptake of proline, betaines, or other osmolytes. However, transport assays revealed low-affinity glycine betaine uptake, mediated by YehZYXW, that was inhibited at high salinity. Thus, YehZYXW is a betaine transporter that shares substrate specificity, but not an osmoregulatory function, with homologues like E. coli ProU. Other work suggests that yehZYXW may be an antivirulence locus whose expression promotes persistent, asymptomatic bacterial infection.

  19. Evolutionary relationships of ATP-Binding Cassette (ABC) uptake porters.

    Science.gov (United States)

    Zheng, Wei Hao; Västermark, Åke; Shlykov, Maksim A; Reddy, Vamsee; Sun, Eric I; Saier, Milton H

    2013-05-06

    The ATP-Binding Cassette (ABC) functional superfamily includes integral transmembrane exporters that have evolved three times independently, forming three families termed ABC1, ABC2 and ABC3, upon which monophyletic ATPases have been superimposed for energy-coupling purposes [e.g., J Membr Biol 231(1):1-10, 2009]. The goal of the work reported in this communication was to understand how the integral membrane constituents of ABC uptake transporters with different numbers of predicted or established transmembrane segments (TMSs) evolved. In a few cases, high resolution 3-dimensional structures were available, and in these cases, their structures plus primary sequence analyses allowed us to predict evolutionary pathways of origin. All of the 35 currently recognized families of ABC uptake proteins except for one (family 21) were shown to be homologous using quantitative statistical methods. These methods involved using established programs that compare native protein sequences with each other, after having compared each sequence with thousands of its own shuffled sequences, to gain evidence for homology. Topological analyses suggested that these porters contain numbers of TMSs ranging from four or five to twenty. Intragenic duplication events occurred multiple times during the evolution of these porters. They originated from a simple primordial protein containing 3 TMSs which duplicated to 6 TMSs, and then produced porters of the various topologies via insertions, deletions and further duplications. Except for family 21 which proved to be related to ABC1 exporters, they are all related to members of the previously identified ABC2 exporter family. Duplications that occurred in addition to the primordial 3 → 6 duplication included 5 → 10, 6 → 12 and 10 → 20 TMSs. In one case, protein topologies were uncertain as different programs gave discrepant predictions. It could not be concluded with certainty whether a 4 TMS ancestral protein or a 5 TMS ancestral protein

  20. ABC transporters P-gp and Bcrp do not limit the brain uptake of the novel antipsychotic and anticonvulsant drug cannabidiol in mice

    Directory of Open Access Journals (Sweden)

    Natalia Brzozowska

    2016-05-01

    Full Text Available Cannabidiol (CBD is currently being investigated as a novel therapeutic for the treatment of CNS disorders like schizophrenia and epilepsy. ABC transporters such as P-glycoprotein (P-gp and breast cancer resistance protein (Bcrp mediate pharmacoresistance in these disorders. P-gp and Bcrp are expressed at the blood brain barrier (BBB and reduce the brain uptake of substrate drugs including various antipsychotics and anticonvulsants. It is therefore important to assess whether CBD is prone to treatment resistance mediated by P-gp and Bcrp. Moreover, it has become common practice in the drug development of CNS agents to screen against ABC transporters to help isolate lead compounds with optimal pharmacokinetic properties. The current study aimed to assess whether P-gp and Bcrp impacts the brain transport of CBD by comparing CBD tissue concentrations in wild-type (WT mice versus mice devoid of ABC transporter genes. P-gp knockout (Abcb1a/b−∕−, Bcrp knockout (Abcg2−∕−, combined P-gp/Bcrp knockout (Abcb1a/b−∕−Abcg2−∕− and WT mice were injected with CBD, before brain and plasma samples were collected at various time-points. CBD results were compared with the positive control risperidone and 9-hydroxy risperidone, antipsychotic drugs that are established ABC transporter substrates. Brain and plasma concentrations of CBD were not greater in P-gp, Bcrp or P-gp/Bcrp knockout mice than WT mice. In comparison, the brain/plasma concentration ratios of risperidone and 9-hydroxy risperidone were profoundly higher in P-gp knockout mice than WT mice. These results suggest that CBD is not a substrate of P-gp or Bcrp and may be free from the complication of reduced brain uptake by these transporters. Such findings provide favorable evidence for the therapeutic development of CBD in the treatment of various CNS disorders.

  1. ABC transporters P-gp and Bcrp do not limit the brain uptake of the novel antipsychotic and anticonvulsant drug cannabidiol in mice.

    Science.gov (United States)

    Brzozowska, Natalia; Li, Kong M; Wang, Xiao Suo; Booth, Jessica; Stuart, Jordyn; McGregor, Iain S; Arnold, Jonathon C

    2016-01-01

    Cannabidiol (CBD) is currently being investigated as a novel therapeutic for the treatment of CNS disorders like schizophrenia and epilepsy. ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) mediate pharmacoresistance in these disorders. P-gp and Bcrp are expressed at the blood brain barrier (BBB) and reduce the brain uptake of substrate drugs including various antipsychotics and anticonvulsants. It is therefore important to assess whether CBD is prone to treatment resistance mediated by P-gp and Bcrp. Moreover, it has become common practice in the drug development of CNS agents to screen against ABC transporters to help isolate lead compounds with optimal pharmacokinetic properties. The current study aimed to assess whether P-gp and Bcrp impacts the brain transport of CBD by comparing CBD tissue concentrations in wild-type (WT) mice versus mice devoid of ABC transporter genes. P-gp knockout (Abcb1a/b (-∕-)), Bcrp knockout (Abcg2 (-∕-)), combined P-gp/Bcrp knockout (Abcb1a/b (-∕-) Abcg2 (-∕-)) and WT mice were injected with CBD, before brain and plasma samples were collected at various time-points. CBD results were compared with the positive control risperidone and 9-hydroxy risperidone, antipsychotic drugs that are established ABC transporter substrates. Brain and plasma concentrations of CBD were not greater in P-gp, Bcrp or P-gp/Bcrp knockout mice than WT mice. In comparison, the brain/plasma concentration ratios of risperidone and 9-hydroxy risperidone were profoundly higher in P-gp knockout mice than WT mice. These results suggest that CBD is not a substrate of P-gp or Bcrp and may be free from the complication of reduced brain uptake by these transporters. Such findings provide favorable evidence for the therapeutic development of CBD in the treatment of various CNS disorders.

  2. Cholestasis: The ABCs of Cellular Mechanisms for Impaired Bile Secretion – Transporters and Genes

    Directory of Open Access Journals (Sweden)

    Eldon A Shaffer

    2002-01-01

    Full Text Available The transport of bile salts, organic anions and cations, bilirubin and other substances from the portal blood into the biliary system is accomplished through the action of an array of transporter proteins in the hepatocyte. Transporters on the basolateral membrane, which faces the space of Disse, are responsible for the uptake of bile salts and organic anions. Once translocated through the hepatocyte to the canalicular membrane, other ATP pumps provide the energy to export bile salts, phospholipids and organic ions into the bile. Canalicular transport is rate limiting. Defects in specific canalicular transporters are responsible for many of the intrahepatic cholestatic syndromes that occur in children and adults. Moreover, cholestasis provokes changes in several transport mechanisms, many of which appear to be compensatory and serve to protect the liver from the toxic effects of accumulated materials. The identification and characterization of the major transporters responsible for bile formation have yielded a more precise classification of the cholestatic syndromes of infancy and childhood, and are unlocking the molecular mechanism of acquired cholestasis in adults. This review identifies the basic physiology of bile production and the actions of the key transporters, indicates the clinical relevance and possible treatments of transport disorders, and provides an illustrative case.

  3. Ion specificity and ionic strength dependence of the osmoregulatory ABC transporter OpuA

    NARCIS (Netherlands)

    Mahmood, N. A. B. Nik; Biemans-Oldehinkel, Esther; Patzlaff, Jason S.; Schuurman-Wolters, Gea K.; Poolman, Bert

    2006-01-01

    The ATPase subunit of the osmoregulatory ATP- binding cassette transporterOpuAfrom Lactococcus lactis has a C- terminal extension, the tandem cystathionine beta- synthase ( CBS) domain, which constitutes the sensor that allows the transporter to sense and respond to osmotic stress ( Biemans-

  4. Drug trafficking in mice: In vivo functions of OATP uptake and ABC efflux transporters

    NARCIS (Netherlands)

    Iusuf, D.

    2013-01-01

    In recent years, there has been increasing attention for drug uptake transporters of the Organic Anion-Transporting Polypeptide (human OATP, mouse Oatp, gene names SLCO, Slco) superfamily. Especially the OATP1A and OATP1B subfamilies turn out to have important physiological and pharmacological

  5. A Survey of the ATP-Binding Cassette (ABC Gene Superfamily in the Salmon Louse (Lepeophtheirus salmonis.

    Directory of Open Access Journals (Sweden)

    Greta Carmona-Antoñanzas

    Full Text Available Salmon lice, Lepeophtheirus salmonis (Krøyer, 1837, are fish ectoparasites causing significant economic damage in the mariculture of Atlantic salmon, Salmo salar Linnaeus, 1758. The control of L. salmonis at fish farms relies to a large extent on treatment with anti-parasitic drugs. A problem related to chemical control is the potential for development of resistance, which in L. salmonis is documented for a number of drug classes including organophosphates, pyrethroids and avermectins. The ATP-binding cassette (ABC gene superfamily is found in all biota and includes a range of drug efflux transporters that can confer drug resistance to cancers and pathogens. Furthermore, some ABC transporters are recognised to be involved in conferral of insecticide resistance. While a number of studies have investigated ABC transporters in L. salmonis, no systematic analysis of the ABC gene family exists for this species. This study presents a genome-wide survey of ABC genes in L. salmonis for which, ABC superfamily members were identified through homology searching of the L. salmonis genome. In addition, ABC proteins were identified in a reference transcriptome of the parasite generated by high-throughput RNA sequencing (RNA-seq of a multi-stage RNA library. Searches of both genome and transcriptome allowed the identification of a total of 33 genes / transcripts coding for ABC proteins, of which 3 were represented only in the genome and 4 only in the transcriptome. Eighteen sequences were assigned to ABC subfamilies known to contain drug transporters, i.e. subfamilies B (4 sequences, C (11 and G (2. The results suggest that the ABC gene family of L. salmonis possesses fewer members than recorded for other arthropods. The present survey of the L. salmonis ABC gene superfamily will provide the basis for further research into potential roles of ABC transporters in the toxicity of salmon delousing agents and as potential mechanisms of drug resistance.

  6. A Survey of the ATP-Binding Cassette (ABC) Gene Superfamily in the Salmon Louse (Lepeophtheirus salmonis).

    Science.gov (United States)

    Carmona-Antoñanzas, Greta; Carmichael, Stephen N; Heumann, Jan; Taggart, John B; Gharbi, Karim; Bron, James E; Bekaert, Michaël; Sturm, Armin

    2015-01-01

    Salmon lice, Lepeophtheirus salmonis (Krøyer, 1837), are fish ectoparasites causing significant economic damage in the mariculture of Atlantic salmon, Salmo salar Linnaeus, 1758. The control of L. salmonis at fish farms relies to a large extent on treatment with anti-parasitic drugs. A problem related to chemical control is the potential for development of resistance, which in L. salmonis is documented for a number of drug classes including organophosphates, pyrethroids and avermectins. The ATP-binding cassette (ABC) gene superfamily is found in all biota and includes a range of drug efflux transporters that can confer drug resistance to cancers and pathogens. Furthermore, some ABC transporters are recognised to be involved in conferral of insecticide resistance. While a number of studies have investigated ABC transporters in L. salmonis, no systematic analysis of the ABC gene family exists for this species. This study presents a genome-wide survey of ABC genes in L. salmonis for which, ABC superfamily members were identified through homology searching of the L. salmonis genome. In addition, ABC proteins were identified in a reference transcriptome of the parasite generated by high-throughput RNA sequencing (RNA-seq) of a multi-stage RNA library. Searches of both genome and transcriptome allowed the identification of a total of 33 genes / transcripts coding for ABC proteins, of which 3 were represented only in the genome and 4 only in the transcriptome. Eighteen sequences were assigned to ABC subfamilies known to contain drug transporters, i.e. subfamilies B (4 sequences), C (11) and G (2). The results suggest that the ABC gene family of L. salmonis possesses fewer members than recorded for other arthropods. The present survey of the L. salmonis ABC gene superfamily will provide the basis for further research into potential roles of ABC transporters in the toxicity of salmon delousing agents and as potential mechanisms of drug resistance.

  7. The ABCs of membrane transporters in health and disease (SLC series): introduction.

    Science.gov (United States)

    Hediger, Matthias A; Clémençon, Benjamin; Burrier, Robert E; Bruford, Elspeth A

    2013-01-01

    The field of transport biology has steadily grown over the past decade and is now recognized as playing an important role in manifestation and treatment of disease. The SLC (solute carrier) gene series has grown to now include 52 families and 395 transporter genes in the human genome. A list of these genes can be found at the HUGO Gene Nomenclature Committee (HGNC) website (see www.genenames.org/genefamilies/SLC). This special issue features mini-reviews for each of these SLC families written by the experts in each field. The existing online resource for solute carriers, the Bioparadigms SLC Tables (www.bioparadigms.org), has been updated and significantly extended with additional information and cross-links to other relevant databases, and the nomenclature used in this database has been validated and approved by the HGNC. In addition, the Bioparadigms SLC Tables functionality has been improved to allow easier access by the scientific community. This introduction includes: an overview of all known SLC and "non-SLC" transporter genes; a list of transporters of water soluble vitamins; a summary of recent progress in the structure determination of transporters (including GLUT1/SLC2A1); roles of transporters in human diseases and roles in drug approval and pharmaceutical perspectives. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. An ABC-Type Cobalt Transport System Is Essential for Growth of Sinorhizobium melilotiat Trace Metal Concentrations ▿ †

    Science.gov (United States)

    Cheng, Jiujun; Poduska, Branislava; Morton, Richard A.; Finan, Turlough M.

    2011-01-01

    We report expression and mutant phenotypes for a gene cluster in Sinorhizobium meliloti, designated cbtJKL, that has been shown to encode an ABC-type cobalt transport system. Transcription of cbtJKLinitiated 384 nucleotides upstream from the cbtJtranslation start codon, and the resulting 5′ region contained a putative B12riboswitch. Expression of the cbtJKLgenes appeared to be controlled by (cobalt-loaded) cobalamin interacting at the B12riboswitch, since (i) a putative B12riboswitch was located within this large upstream region, (ii) cbtJtranscription was repressed upon addition of cobalt or vitamin B12, and (iii) deletions in the B12riboswitch resulted in constitutive cbtJKLtranscription. Insertion mutants in cbtJKLfailed to grow in LB medium, and growth was restored through the addition of cobalt but not other metals. This growth phenotype appeared to be due to the chelation of cobalt present in LB, and cbtJKLmutants also failed to grow in minimal medium containing the chelating agent EDTA unless the medium was supplemented with additional or excess cobalt. In uptake experiments, 57Co2+accumulation was high in wild-type cells expressing the cbtJKLgenes, whereas wild-type cells in which cbtJKLexpression was repressed showed reduced accumulation. In cbtJKLmutant cells, 57Co2+accumulation was reduced relative to that of the wild type, and presumably, this residual cobalt transport occurred via an alternate ion uptake system(s) that is not specific to cobalt. In symbiosis, the alternate system(s) appeared to mediate cobalt transport into bacteroid cells, as low cbtJKLexpression was detected in bacteroids and cbtJKLmutants formed N2-fixing nodules on alfalfa. PMID:21725018

  9. Classification of a Haemophilus influenzae ABC Transporter HI1470/71 through Its Cognate Molybdate Periplasmic Binding Protein, MolA

    Energy Technology Data Exchange (ETDEWEB)

    Tirado-Lee, Leidamarie; Lee, Allen; Rees, Douglas C.; Pinkett, Heather W. (CIT); (NWU)

    2014-10-02

    molA (HI1472) from H. influenzae encodes a periplasmic binding protein (PBP) that delivers substrate to the ABC transporter MolB{sub 2}C{sub 2} (formerly HI1470/71). The structures of MolA with molybdate and tungstate in the binding pocket were solved to 1.6 and 1.7 {angstrom} resolution, respectively. The MolA-binding protein binds molybdate and tungstate, but not other oxyanions such as sulfate and phosphate, making it the first class III molybdate-binding protein structurally solved. The {approx}100 {mu}M binding affinity for tungstate and molybdate is significantly lower than observed for the class II ModA molybdate-binding proteins that have nanomolar to low micromolar affinity for molybdate. The presence of two molybdate loci in H. influenzae suggests multiple transport systems for one substrate, with molABC constituting a low-affinity molybdate locus.

  10. Development, Maintenance, and Reversal of Multiple Drug Resistance: At the Crossroads of TFPI1, ABC Transporters, and HIF1

    Directory of Open Access Journals (Sweden)

    Terra Arnason

    2015-10-01

    Full Text Available Early detection and improved therapies for many cancers are enhancing survival rates. Although many cytotoxic therapies are approved for aggressive or metastatic cancer; response rates are low and acquisition of de novo resistance is virtually universal. For decades; chemotherapeutic treatments for cancer have included anthracyclines such as Doxorubicin (DOX; and its use in aggressive tumors appears to remain a viable option; but drug resistance arises against DOX; as for all other classes of compounds. Our recent work suggests the anticoagulant protein Tissue Factor Pathway Inhibitor 1α (TFPI1α plays a role in driving the development of multiple drug resistance (MDR; but not maintenance; of the MDR state. Other factors; such as the ABC transporter drug efflux pumps MDR-1/P-gp (ABCB1 and BCRP (ABCG2; are required for MDR maintenance; as well as development. The patient population struggling with therapeutic resistance specifically requires novel treatment options to resensitize these tumor cells to therapy. In this review we discuss the development, maintenance, and reversal of MDR as three distinct phases of cancer biology. Possible means to exploit these stages to reverse MDR will be explored. Early molecular detection of MDRcancers before clinical failure has the potential to offer new approaches to fighting MDRcancer.

  11. ABC- and SLC-Transporters in Murine and Bovine Mammary Epithelium

    DEFF Research Database (Denmark)

    Yagdiran, Yagmur; Oskarsson, Agneta; Knight, Christopher H.

    2016-01-01

    and SLC transporters in murine mammary tissue of different gestation and lactation stages, in murine mammary cells (HC11) featuring resting and secreting phenotypes and in bovine mammary tissue and cells (BME-UV). Effects on transporter expression and function of the imidazole fungicide prochloraz...... and lactation, whereas MDR1, MRP1, OATP1A5 and OCTN1 were decreased, compared to expressions in virgins. All transporters measured inmammary glands of mice were detected in bovine mammary tissue and in HC11 cells, while only MDR1 and MRP1 were detected in BME-UV cells. Prochloraz treatment induced MDR1 gene...... and protein expression in both differentiated HC11 and BME-UV cells and increased protein function in HC11 cells, resulting in decreased accumulation of the MDR1substrate digoxin. In conclusion, our results demonstrate that murine (HC11) and bovine (BME-UV) mammary epithelial cells can be applied...

  12. Spent fuel transportation accident: a state's involvement

    International Nuclear Information System (INIS)

    Neuweg, M.

    1978-01-01

    On February 9, 1978 at 8:20 p.m., the duty officer for the Illinois Radiological Assistance Team was notified that a shipment containing uranium and plutonium was involved in an accident near Gibson City, Illinois on Route 54. It was reported that a pig containing an unknown amount of uranium and plutonium was involved. The Illinois District 6A State Police were called to the scene and secured the area. The duty officer in the meantime learned after numerous telephone calls, approximately 1 hour after the first notice was received, that the pig actually was a 48,000 pound cask containing 6 spent fuel rods and the tractor-trailer had split apart and was blocking one lane of the highway. The shipment had departed from Dresden Nuclear Power Station, Morris, Illinois, enroute to Babcox and Wilcox in Lynchburg, Virginia. Initial reports indicated the vehicle had split apart. Actually, the semi-trailer bed had buckled beneath the cask due to apparent excess stress. The cask remained entirely intact and was not damaged, but the state highway was closed to traffic. The State Radiological Assistance Team was dispatched and arrived on the scene at 12:45 a.m. Immediate radiation monitoring revealed a reading of 4 milliroentgen per hour at 10 feet from the cask. No contamination existed nor was anyone exposed to radiation unnecessarily. The cask was transferred to a Tri-State semi-trailer vehicle the following morning at approximately 6:30 a.m. At 9:30 a.m., February 10, the new vehicle was again enroute to its destination. This incident demonstrated typical occurrences involving transportation radiation accident: misinformation and/or lack of information on the initial response notification, inaccuracies of radiation monitorings at the scene of the accident, inconsistencies concerning the occurrences of the accident and unfamiliar terminology utilized by personnel first on the scene, i.e., pig, cask, vehicle split apart, etc

  13. Reversal of resistance by GF120918 in cell lines expressing the ABC half-transporter, MXR

    DEFF Research Database (Denmark)

    de Bruin, M; Miyake, K; Litman, Thomas

    1999-01-01

    -80, a subline expressing a newly identified mitoxantrone transporter, MXR. GF120918 was ineffective in sensitizing MRP-overexpressing MCF-7 VP-16 cells to etoposide as determined by cytotoxicity studies. In flow cytometry experiments, rhodamine 123 efflux in S1-B1-20 cells was decreased at GF120918...

  14. ABC protein transport of MRI contrast agents in canalicular rat liver plasma vesicles and yeast vacuoles

    International Nuclear Information System (INIS)

    Pascolo, Lorella; Petrovic, Sinisa; Cupelli, Felicia; Bruschi, Carlo V.; Anelli, Pier Lucio; Lorusso, Vito; Visigalli, Massimo; Uggeri, Fulvio; Tiribelli, Claudio

    2001-01-01

    The mechanism of excretion into bile of hepatospecific magnetic resonance imaging (MRI) contrast media employed labeled Gd-reagents EOB.DTPA, BOPTA, B 20790 (iopanoate-linked), and B 21690 (glycocholate-linked) for measurement in rat liver canalicular plasma membrane vesicles and yeast vacuoles. The presence of ATP gave threefold greater transport of B 20790 and B 21690 than of EOB.DTPA and BOPTA. In yeast vacuoles the ATP stimulatory effect was eightfold with B 20790 and fivefold greater for B 21690, whereas in YCF1- or YLLO115w-deleted yeast cells the transport was significantly reduced and absent from double mutants, YCF1 and YLLO15w. The transport was similar in wild-type and deletant cells for B 21690; taurocholate gave 85% inhibition. These data suggest that bilary secretion of structurally related MRI agents depend on molecular structure. The findings are suggestive as of possible value for clinical diagnosis of inherited hyperbilirubinemias and other liver disorders

  15. Downregulation of eIF4G by microRNA-503 enhances drug sensitivity of MCF-7/ADR cells through suppressing the expression of ABC transport proteins.

    Science.gov (United States)

    Pan, Xia; Yang, Xiaoyan; Zang, Jinglei; Zhang, Si; Huang, Nan; Guan, Xinxin; Zhang, Jianhua; Wang, Zhihui; Li, Xi; Lei, Xiaoyong

    2017-06-01

    Overexpression of adenosine triphosphate-binding cassette (ABC) transport protein is emerging as a critical contributor to anticancer drug resistance. The eukaryotic translation initiation factor (eIF) 4F complex, the key modulator of mRNA translation, is regulated by the phosphoinositide 3-kinase-AKT-mammalian target of rapamycin pathway in anticancer drug-resistant tumors. The present study demonstrated the roles of ABC translation protein alterations in the acquisition of the Adriamycin (ADM)-resistant phenotype of MCF-7 human breast cells. Quantitative polymerase chain reaction and western blot analysis were applied to examine the differences in mRNA and protein levels, respectively. It was found that the expression of the ABC sub-family B member 1, ABC sub-family C member 1 and ABC sub-family G member 2 transport proteins were upregulated in MCF-7/ADR cells. An MTT assay was used to detect the cell viability, from the results MCF-7/ADR cells were less sensitive to ADM, tamoxifen (TAM) and taxol (TAX) treatment compared with MCF-7 cells. We predicted that the 3'-untranslated region of eukaryotic translation initiation factor 4-γ 1 (eIF4G) contains a potential miRNA binding site for microRNA (miR)-503 through using computational programs. These binding sites were confirmed by luciferase reporter assays. eIF4G mRNA degradation was accelerated in cells transfected with miR-503 mimics. Furthermore, it was demonstrated that eIF4G and ABC translation proteins were significantly downregulated in MCF-7/ADR cells after transfection with miR-503. It was found that miR-503 mimics could sensitize the cells to treatment with ADM, TAM and TAX. These findings demonstrated for the first time that eIF4G acted as a key factor in MCF-7/ADR cells, and may be an efficient agent for preventing and reversing multi-drug resistance in breast cancer.

  16. ABC Transporters and Their Role in the Neoadjuvant Treatment of Esophageal Cancer

    Directory of Open Access Journals (Sweden)

    David Vrana

    2018-03-01

    Full Text Available The prognosis of esophageal cancer (EC is poor, despite considerable effort of both experimental scientists and clinicians. The tri-modality treatment consisting of neoadjuvant chemoradiation followed by surgery has remained the gold standard over decades, unfortunately, without significant progress in recent years. Suitable prognostic factors indicating which patients will benefit from this tri-modality treatment are missing. Some patients rapidly progress on the neoadjuvant chemoradiotherapy, which is thus useless and sometimes even harmful. At the same time, other patients achieve complete remission on neoadjuvant chemoradiotherapy and subsequent surgery may increase their risk of morbidity and mortality. The prognosis of patients ranges from excellent to extremely poor. Considering these differences, the role of drug metabolizing enzymes and transporters, among other factors, in the EC response to chemotherapy may be more important compared, for example, with pancreatic cancer where all patients progress on chemotherapy regardless of the treatment or disease stage. This review surveys published literature describing the potential role of ATP-binding cassette transporters, the genetic polymorphisms, epigenetic regulations, and phenotypic changes in the prognosis and therapy of EC. The review provides knowledge base for further research of potential predictive biomarkers that will allow the stratification of patients into defined groups for optimal therapeutic outcome.

  17. Conserved ABC Transport System Regulated by the General Stress Response Pathways of Alpha- and Gammaproteobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Herrou, Julien; Willett, Jonathan W.; Czyż, Daniel M.; Babnigg, Gyorgy; Kim, Youngchang; Crosson, Sean; Stock, Ann M.

    2016-12-19

    ABSTRACT

    Brucella abortusσE1is an EcfG family sigma factor that regulates the transcription of dozens of genes in response to diverse stress conditions and is required for maintenance of chronic infection in a mouse model. A putative ATP-binding cassette transporter operon,bab1_0223-bab1_0226, is among the most highly activated gene sets in the σE1regulon. The proteins encoded by the operon resemble quaternary ammonium-compatible solute importers but are most similar in sequence to the broadly conserved YehZYXW system, which remains largely uncharacterized. Transcription ofyehZYXWis activated by the general stress sigma factor σSinEnterobacteriaceae, which suggests a functional role for this transport system in bacterial stress response across the classesAlphaproteobacteriaandGammaproteobacteria. We present evidence thatB. abortusYehZYXW does not function as an importer of known compatible solutes under physiological conditions and does not contribute to the virulence defect of a σE1-null strain. The solein vitrophenotype associated with genetic disruption of this putative transport system is reduced growth in the presence of high Li+ion concentrations. A crystal structure ofB. abortusYehZ revealed a class II periplasmic binding protein fold with significant structural homology toArchaeoglobus fulgidusProX, which binds glycine betaine. However, the structure

  18. Lateral gene transfer of an ABC transporter complex between major constituents of the human gut microbiome

    Directory of Open Access Journals (Sweden)

    Meehan Conor J

    2012-11-01

    Full Text Available Abstract Background Several links have been established between the human gut microbiome and conditions such as obesity and inflammatory bowel syndrome. This highlights the importance of understanding what properties of the gut microbiome can affect the health of the human host. Studies have been undertaken to determine the species composition of this microbiome and infer functional profiles associated with such host properties. However, lateral gene transfer (LGT between community members may result in misleading taxonomic attributions for the recipient organisms, thus making species-function links difficult to establish. Results We identified a peptides/nickel transport complex whose components differed in abundance based upon levels of host obesity, and assigned the encoded proteins to members of the microbial community. Each protein was assigned to several distinct taxonomic groups, with moderate levels of agreement observed among different proteins in the complex. Phylogenetic trees of these proteins produced clusters that differed greatly from taxonomic attributions and indicated that habitat-directed LGT of this complex is likely to have occurred, though not always between the same partners. Conclusions These findings demonstrate that certain membrane transport systems may be an important factor within an obese-associated gut microbiome and that such complexes may be acquired several times by different strains of the same species. Additionally, an example of individual proteins from different organisms being transferred into one operon was observed, potentially demonstrating a functional complex despite the donors of the subunits being taxonomically disparate. Our results also highlight the potential impact of habitat-directed LGT on the resident microbiota.

  19. Drosophila ABC transporter mutants white, brown and scarlet have altered contents and distribution of biogenic amines in the brain.

    Science.gov (United States)

    Borycz, J; Borycz, J A; Kubów, A; Lloyd, V; Meinertzhagen, I A

    2008-11-01

    Monoamines such as dopamine, histamine and serotonin (5-HT) are widely distributed throughout the brain of the fruit fly Drosophila melanogaster, where many of their actions have been investigated. For example, histamine is released from photoreceptor synapses in the lamina neuropile of the visual system. Mutations of the genes white, an important eye pigmentation marker in fly genetics that encodes an ABC transporter, and its binding partner brown, cause neural phenotypes not readily reconciled solely with actions in eye pigmentation. We find that flies mutant for these genes, and another binding partner, scarlet, have about half the wild-type amount of histamine in the head, as well as reduced 5-HT and dopamine. These differences parallel reductions in immunoreactivity to the corresponding biogenic amines. They also correlate with the amine content of fractions after differential centrifugation of head homogenates. Thus, most of the amine is found in the vesicle-rich fraction of wild-type head homogenates, whereas it is found in the supernatant fractions from white, brown and scarlet flies. White co-expresses in lamina epithelial glia with Ebony, which conjugates histamine to beta-alanine. Histamine is then released when the conjugate is hydrolyzed in photoreceptors, by Tan. Mutant white ameliorates the effects of tan on head histamine whereas it exacerbates the effects of ebony. Our results are consistent with the proposal that histamine uptake by the epithelial glia may be white dependent. Behavioral abnormalities in white, brown and scarlet mutants could arise because aminergic neurons in the Drosophila brain have reduced amine for release.

  20. Mutational analysis of the binding affinity and transport activity for N-acetylglucosamine of the novel ABC transporter Ngc in the chitin-degrader Streptomyces olivaceoviridis.

    Science.gov (United States)

    Saito, A; Schrempf, H

    2004-06-01

    The highly differentiated bacterium Streptomyces olivaceoviridis efficiently hydrolyses chitin, a highly abundant natural polysaccharide, to low molecular weight products including N-acetylglucosamine (NAG) and N,N' -diacetylchitobiose (chitobiose). NAG is taken up by a PTS (phosphoenolpyruvate-dependent phosphotransferase system) which includes the PtsC2 protein, and via the ABC (ATP-binding cassette) transporter Ngc, which itself includes the substrate-binding protein NgcE. This is at present the only ABC transporter which is known to mediate specific uptake of NAG (K(m) 0.48 microM, V(max) 1.3 nmol/min/mg dry weight) and is competitively inhibited by chitobiose (K(i) 0.68 microM). The latter finding suggests that the Ngc system transports both NAG and chitobiose efficiently. To identify amino acid residues required for the function of NgcE, either the wild-type or one of several mutant forms of the ngcE gene was introduced into the strain S. olivaceoviridis DeltaNgcE/DeltaPtsC1/DeltaPtsC2, which lacks both functional transport systems for NAG, and chromosomal recombinants were selected. Based on the in vivo transport parameters of the recombinants, and the in vitro binding characteristics of the corresponding purified proteins, the following conclusions can be drawn. (1) Replacement of the C-terminally located residue Y396 by A (Y396A) has little effect on ligand-binding or transport parameters. The W395A mutation also induced little change in the substrate affinity in vitro, but it led in vivo to a marked increase (11 fold) in K(m), and enhanced V(max) (by 1.5 fold). (2) The amino acids Y201 and W280 both contribute (51% and 38%) to the ligand-binding capacity of NgcE. They are both very important for the in vivo function of the complete transport apparatus; strains expressing either Y201A or W280A show drastically (100 or 150 times) enhanced K(m) values. (3) The concomitant presence of either Y200 and W280 or Y201 and W280 is essential for the function of Ngc

  1. Live cell FRET microscopy: homo- and heterodimerization of two human peroxisomal ABC transporters, the adrenoleukodystrophy protein (ALDP, ABCD1) and PMP70 (ABCD3).

    Science.gov (United States)

    Hillebrand, Merle; Verrier, Sophie E; Ohlenbusch, Andreas; Schäfer, Annika; Söling, Hans-Dieter; Wouters, Fred S; Gärtner, Jutta

    2007-09-14

    The adrenoleukodystrophy protein (ALDP) and the 70-kDa peroxisomal membrane protein (PMP70) are half-ATP-binding cassette (ABC) transporters in the mammalian peroxisome membrane. Mutations in the gene encoding ALDP result in a devastating neurodegenerative disorder, X-linked adrenoleukodystrophy (X-ALD) that is associated with elevated levels of very long chain fatty acids because of impaired peroxisomal beta-oxidation. The interactions of peroxisomal ABC transporters, their role in the peroxisomal membrane, and their functions in disease pathogenesis are poorly understood. Studies on ABC transporters revealed that half-transporters have to dimerize to gain functionality. So far, conflicting observations are described for ALDP. By the use of in vitro methods (yeast two-hybrid and immunoprecipitation assays) on the one hand, it was shown that ALDP can form homodimers as well as heterodimers with PMP70 and ALDR, while on the other hand, it was demonstrated that ALDP and PMP70 exclusively homodimerize. To circumvent the problems of artificial interactions due to biochemical sample preparation in vitro, we investigated protein-protein interaction of ALDP in its physiological environment by FRET microscopy in intact living cells. The statistical relevance of FRET data was determined in two different ways using probability distribution shift analysis and Kolmogorov-Smirnov statistics. We demonstrate in vivo that ALDP and PMP70 form homodimers as well as ALDP/PMP70 heterodimers where ALDP homodimers predominate. Using C-terminal deletion constructs of ALDP, we demonstrate that the last 87 C-terminal amino acids harbor the most important protein domain mediating these interactions, and that the N-terminal transmembrane region of ALDP has an additional stabilization effect on ALDP homodimers. Loss of ALDP homo- or heterodimerization is highly relevant for understanding the disease mechanisms of X-ALD.

  2. Combined phylogeny and neighborhood analysis of the evolution of the ABC transporters conferring multiple drug resistance in hemiascomycete yeasts

    Directory of Open Access Journals (Sweden)

    Goffeau André

    2009-10-01

    Full Text Available Abstract Background Pleiotropic Drug Resistant transporters (PDR are members of the ATP-Binding Cassette (ABC subfamily which export antifungals and other xenobiotics in fungi and plants. This subfamily of transmembrane transporters has nine known members in Saccharomyces cerevisiae. We have analyzed the complex evolution of the pleiotropic drug resistance proteins (Pdrp subfamily where gene duplications and deletions occur independently in individual genomes. This study was carried out on 62 Pdrp from nine hemiascomycetous species, seven of which span 6 of the 14 clades of the Saccharomyces complex while the two others species, Debaryomyces hansenii and Yarrowia lipolytica, are further apart from an evolutive point of view. Results Combined phylogenetic and neighborhood analyses enabled us to identify five Pdrp clusters in the Saccharomyces complex. Three of them comprise orthologs of the Pdrp sensu stricto, Pdr5p, Pdr10p, Pdr12p, Pdr15p, Snq2p and YNR070wp. The evolutive pathway of the orthologs of Snq2 and YNR070w is particularly complex due to a tandem gene array in Eremothecium gossypii, Kluyveromyces lactis and Saccharomyces (Lachancea kluyveri. This pathway and different cases of duplications and deletions were clarified by using a neighborhood analysis based on synteny. For the two distant species, Yarrowia lipolytica and Debaryomyces hansenii, no neighborhood evidence is available for these clusters and many homologs of Pdr5 and Pdr15 are phylogenetically assigned to species-based clusters. Two other clusters comprise the orthologs of the sensu lato Pdrp, Aus1p/Pdr11p and YOL075cp respectively. The evolutionary pathway of these clusters is simpler. Nevertheless, orthologs of these genes are missing in some species. Conclusion Numerous duplications were traced among the Hemiascomycetous Pdrp studied. The role of the Whole Genome Duplication (WGD is sorted out and our analyses confirm the common ancestrality of Pdr5p and Pdr15p. A tandem

  3. Combined phylogeny and neighborhood analysis of the evolution of the ABC transporters conferring multiple drug resistance in hemiascomycete yeasts.

    Science.gov (United States)

    Seret, Marie-Line; Diffels, Julie F; Goffeau, André; Baret, Philippe V

    2009-10-01

    Pleiotropic Drug Resistant transporters (PDR) are members of the ATP-Binding Cassette (ABC) subfamily which export antifungals and other xenobiotics in fungi and plants. This subfamily of transmembrane transporters has nine known members in Saccharomyces cerevisiae. We have analyzed the complex evolution of the pleiotropic drug resistance proteins (Pdrp) subfamily where gene duplications and deletions occur independently in individual genomes. This study was carried out on 62 Pdrp from nine hemiascomycetous species, seven of which span 6 of the 14 clades of the Saccharomyces complex while the two others species, Debaryomyces hansenii and Yarrowia lipolytica, are further apart from an evolutive point of view. Combined phylogenetic and neighborhood analyses enabled us to identify five Pdrp clusters in the Saccharomyces complex. Three of them comprise orthologs of the Pdrp sensu stricto, Pdr5p, Pdr10p, Pdr12p, Pdr15p, Snq2p and YNR070wp. The evolutive pathway of the orthologs of Snq2 and YNR070w is particularly complex due to a tandem gene array in Eremothecium gossypii, Kluyveromyces lactis and Saccharomyces (Lachancea) kluyveri. This pathway and different cases of duplications and deletions were clarified by using a neighborhood analysis based on synteny. For the two distant species, Yarrowia lipolytica and Debaryomyces hansenii, no neighborhood evidence is available for these clusters and many homologs of Pdr5 and Pdr15 are phylogenetically assigned to species-based clusters. Two other clusters comprise the orthologs of the sensu lato Pdrp, Aus1p/Pdr11p and YOL075cp respectively. The evolutionary pathway of these clusters is simpler. Nevertheless, orthologs of these genes are missing in some species. Numerous duplications were traced among the Hemiascomycetous Pdrp studied. The role of the Whole Genome Duplication (WGD) is sorted out and our analyses confirm the common ancestrality of Pdr5p and Pdr15p. A tandem gene array is observed in Eremothecium gossypii. One

  4. ABC transporters and the proteasome complex are implicated in susceptibility to Stevens-Johnson syndrome and toxic epidermal necrolysis across multiple drugs.

    Directory of Open Access Journals (Sweden)

    Paola Nicoletti

    Full Text Available Stevens-Johnson syndrome (SJS and Toxic Epidermal Necrolysis (TEN represent rare but serious adverse drug reactions (ADRs. Both are characterized by distinctive blistering lesions and significant mortality rates. While there is evidence for strong drug-specific genetic predisposition related to HLA alleles, recent genome wide association studies (GWAS on European and Asian populations have failed to identify genetic susceptibility alleles that are common across multiple drugs. We hypothesize that this is a consequence of the low to moderate effect size of individual genetic risk factors. To test this hypothesis we developed Pointer, a new algorithm that assesses the aggregate effect of multiple low risk variants on a pathway using a gene set enrichment approach. A key advantage of our method is the capability to associate SNPs with genes by exploiting physical proximity as well as by using expression quantitative trait loci (eQTLs that capture information about both cis- and trans-acting regulatory effects. We control for known bias-inducing aspects of enrichment based analyses, such as: 1 gene length, 2 gene set size, 3 presence of biologically related genes within the same linkage disequilibrium (LD region, and, 4 genes shared among multiple gene sets. We applied this approach to publicly available SJS/TEN genome-wide genotype data and identified the ABC transporter and Proteasome pathways as potentially implicated in the genetic susceptibility of non-drug-specific SJS/TEN. We demonstrated that the innovative SNP-to-gene mapping phase of the method was essential in detecting the significant enrichment for those pathways. Analysis of an independent gene expression dataset provides supportive functional evidence for the involvement of Proteasome pathways in SJS/TEN cutaneous lesions. These results suggest that Pointer provides a useful framework for the integrative analysis of pharmacogenetic GWAS data, by increasing the power to detect

  5. Civilsamfundets ABC

    DEFF Research Database (Denmark)

    Lund, Anker Brink; Meyer, Gitte

    Filantropiske fonde og foreninger får stadig større indflydelse på udviklingen af det danske samfund – fra kunst, kultur, byggeri og byudvikling til forskning og udvikling af den danske velfærdsstat. Gennem 32 essays giver Anker Brink Lund og Gitte Meyer en oplysende – og polemisk – analyse af de...... for almenvelllet? CIVILSAMFUNDETS ABC er skrevet på baggrund af et udredningsprojekt om civilsamfundets rolle i det danske samfund. Såvel udredningsprojektet som ABC’en er finansieret af Realdania...

  6. Detergent screening and purification of the human liver ABC transporters BSEP (ABCB11 and MDR3 (ABCB4 expressed in the yeast Pichia pastoris.

    Directory of Open Access Journals (Sweden)

    Philipp Ellinger

    Full Text Available The human liver ATP-binding cassette (ABC transporters bile salt export pump (BSEP/ABCB11 and the multidrug resistance protein 3 (MDR3/ABCB4 fulfill the translocation of bile salts and phosphatidylcholine across the apical membrane of hepatocytes. In concert with ABCG5/G8, these two transporters are responsible for the formation of bile and mutations within these transporters can lead to severe hereditary diseases. In this study, we report the heterologous overexpression and purification of human BSEP and MDR3 as well as the expression of the corresponding C-terminal GFP-fusion proteins in the yeast Pichia pastoris. Confocal laser scanning microscopy revealed that BSEP-GFP and MDR3-GFP are localized in the plasma membrane of P. pastoris. Furthermore, we demonstrate the first purification of human BSEP and MDR3 yielding ∼1 mg and ∼6 mg per 100 g of wet cell weight, respectively. By screening over 100 detergents using a dot blot technique, we found that only zwitterionic, lipid-like detergents such as Fos-cholines or Cyclofos were able to extract both transporters in sufficient amounts for subsequent functional analysis. For MDR3, fluorescence-detection size exclusion chromatography (FSEC screens revealed that increasing the acyl chain length of Fos-Cholines improved monodispersity. BSEP purified in n-dodecyl-β-D-maltoside or Cymal-5 after solubilization with Fos-choline 16 from P. pastoris membranes showed binding to ATP-agarose. Furthermore, detergent-solubilized and purified MDR3 showed a substrate-inducible ATPase activity upon addition of phosphatidylcholine lipids. These results form the basis for further biochemical analysis of human BSEP and MDR3 to elucidate the function of these clinically relevant ABC transporters.

  7. Detergent Screening and Purification of the Human Liver ABC Transporters BSEP (ABCB11) and MDR3 (ABCB4) Expressed in the Yeast Pichia pastoris

    Science.gov (United States)

    Stindt, Jan; Smits, Sander H. J.; Schmitt, Lutz

    2013-01-01

    The human liver ATP-binding cassette (ABC) transporters bile salt export pump (BSEP/ABCB11) and the multidrug resistance protein 3 (MDR3/ABCB4) fulfill the translocation of bile salts and phosphatidylcholine across the apical membrane of hepatocytes. In concert with ABCG5/G8, these two transporters are responsible for the formation of bile and mutations within these transporters can lead to severe hereditary diseases. In this study, we report the heterologous overexpression and purification of human BSEP and MDR3 as well as the expression of the corresponding C-terminal GFP-fusion proteins in the yeast Pichia pastoris. Confocal laser scanning microscopy revealed that BSEP-GFP and MDR3-GFP are localized in the plasma membrane of P. pastoris. Furthermore, we demonstrate the first purification of human BSEP and MDR3 yielding ∼1 mg and ∼6 mg per 100 g of wet cell weight, respectively. By screening over 100 detergents using a dot blot technique, we found that only zwitterionic, lipid-like detergents such as Fos-cholines or Cyclofos were able to extract both transporters in sufficient amounts for subsequent functional analysis. For MDR3, fluorescence-detection size exclusion chromatography (FSEC) screens revealed that increasing the acyl chain length of Fos-Cholines improved monodispersity. BSEP purified in n-dodecyl-β-D-maltoside or Cymal-5 after solubilization with Fos-choline 16 from P. pastoris membranes showed binding to ATP-agarose. Furthermore, detergent-solubilized and purified MDR3 showed a substrate-inducible ATPase activity upon addition of phosphatidylcholine lipids. These results form the basis for further biochemical analysis of human BSEP and MDR3 to elucidate the function of these clinically relevant ABC transporters. PMID:23593265

  8. A burst of ABC genes in the genome of the polyphagous spider mite Tetranychus urticae

    NARCIS (Netherlands)

    Dermauw, W.; Osborne, E.J.; Clark, R.M.; Grbić, M.; Tirry, L.; Van Leeuwen, T.

    2013-01-01

    Background: The ABC (ATP-binding cassette) gene superfamily is widespread across all living species. The majority of ABC genes encode ABC transporters, which are membrane-spanning proteins capable of transferring substrates across biological membranes by hydrolyzing ATP. Although ABC transporters

  9. Inactivation of the peroxisomal ABCD2 transporter in the mouse leads to late-onset ataxia involving mitochondria, Golgi and endoplasmic reticulum damage

    NARCIS (Netherlands)

    Ferrer, Isidre; Kapfhammer, Josef P.; Hindelang, Colette; Kemp, Stephan; Troffer-Charlier, Nathalie; Broccoli, Vania; Callyzot, Noëlle; Mooyer, Petra; Selhorst, Jacqueline; Vreken, Peter; Wanders, Ronald J. A.; Mandel, Jean Louis; Pujol, Aurora

    2005-01-01

    ATP-binding cassette (ABC) transporters facilitate unidirectional translocation of chemically diverse substances, ranging from peptides to lipids, across cell or organelle membranes. In peroxisomes, a subfamily of four ABC transporters (ABCD1 to ABCD4) has been related to fatty acid transport,

  10. A mutation within the extended X loop abolished substrate-induced ATPase activity of the human liver ATP-binding cassette (ABC) transporter MDR3.

    Science.gov (United States)

    Kluth, Marianne; Stindt, Jan; Dröge, Carola; Linnemann, Doris; Kubitz, Ralf; Schmitt, Lutz

    2015-02-20

    The human multidrug resistance protein 3 (MDR3/ABCB4) belongs to the ubiquitous family of ATP-binding cassette (ABC) transporters and is located in the canalicular membrane of hepatocytes. There it flops the phospholipids of the phosphatidylcholine (PC) family from the inner to the outer leaflet. Here, we report the characterization of wild type MDR3 and the Q1174E mutant, which was identified previously in a patient with progressive familial intrahepatic cholestasis type 3 (PFIC-3). We expressed different variants of MDR3 in the yeast Pichia pastoris, purified the proteins via tandem affinity chromatography, and determined MDR3-specific ATPase activity in the presence or absence of phospholipids. The ATPase activity of wild type MDR3 was stimulated 2-fold by liver PC or 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine lipids. Furthermore, the cross-linking of MDR3 with a thiol-reactive fluorophore blocked ATP hydrolysis and exhibited no PC stimulation. Similarly, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin lipids did not induce an increase of wild type MDR3 ATPase activity. The phosphate analogues beryllium fluoride and aluminum fluoride led to complete inhibition of ATPase activity, whereas orthovanadate inhibited exclusively the PC-stimulated ATPase activity of MDR3. The Q1174E mutation is located in the nucleotide-binding domain in direct proximity of the leucine of the ABC signature motif and extended the X loop, which is found in ABC exporters. Our data on the Q1174E mutant demonstrated basal ATPase activity, but PC lipids were incapable of stimulating ATPase activity highlighting the role of the extended X loop in the cross-talk of the nucleotide-binding domain and the transmembrane domain. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Interaction of BDE-47 and its Hydroxylated Metabolite 6-OH-BDE-47 with the Human ABC Efflux Transporters P-gp and BCRP: Considerations for Human Exposure and Risk Assessment

    Science.gov (United States)

    ATP binding cassette (ABC) transporters, including P-glycoprotein (P-gp; also known as MDR1, ABCB1) and breast cancer resistance protein (BCRP; also known as ABCG2), are membrane-bound proteins that mediate the cellular efflux of xenobiotics as an important defense against chemic...

  12. Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

    Science.gov (United States)

    2012-01-01

    Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC) Superfamily and Major Facilitator Superfamily (MFS) in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3 H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to improve alcoholic

  13. Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation.

    Science.gov (United States)

    Teixeira, Miguel C; Godinho, Cláudia P; Cabrito, Tânia R; Mira, Nuno P; Sá-Correia, Isabel

    2012-07-27

    The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC) Superfamily and Major Facilitator Superfamily (MFS) in S. cerevisiae were scrutinized for a role in ethanol stress resistance. A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased ³H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to improve alcoholic fermentation performance for sustainable bio

  14. Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Teixeira Miguel C

    2012-07-01

    Full Text Available Abstract Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC Superfamily and Major Facilitator Superfamily (MFS in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3 H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to

  15. LrABCF1, a GCN-type ATP-binding cassette transporter from lilium regale, is involved in defense responses against viral and fungal pathogens

    Science.gov (United States)

    ATP-binding cassette (ABC) transporters are essential for membrane translocation in diverse biological processes, such as plant development and defense response. Here, a general control non-derepressible (GCN)-type ABC transporter gene, designated LrABCF1, was identified from Cucumber mosaic virus (...

  16. Human ATP-binding cassette transporter 1 (ABC1): Genomic organization and identification of the genetic defect in the original Tangier disease kindred

    Science.gov (United States)

    Remaley, Alan T.; Rust, Stephan; Rosier, Marie; Knapper, Cathy; Naudin, Laurent; Broccardo, Cyril; Peterson, Katherine M.; Koch, Christine; Arnould, Isabelle; Prades, Catherine; Duverger, Nicholas; Funke, Harald; Assman, Gerd; Dinger, Maria; Dean, Michael; Chimini, Giovanna; Santamarina-Fojo, Silvia; Fredrickson, Donald S.; Denefle, Patrice; Brewer, H. Bryan

    1999-01-01

    Tangier disease is characterized by low serum high density lipoproteins and a biochemical defect in the cellular efflux of lipids to high density lipoproteins. ABC1, a member of the ATP-binding cassette family, recently has been identified as the defective gene in Tangier disease. We report here the organization of the human ABC1 gene and the identification of a mutation in the ABC1 gene from the original Tangier disease kindred. The organization of the human ABC1 gene is similar to that of the mouse ABC1 gene and other related ABC genes. The ABC1 gene contains 49 exons that range in size from 33 to 249 bp and is over 70 kb in length. Sequence analysis of the ABC1 gene revealed that the proband for Tangier disease was homozygous for a deletion of nucleotides 3283 and 3284 (TC) in exon 22. The deletion results in a frameshift mutation and a premature stop codon starting at nucleotide 3375. The product is predicted to encode a nonfunctional protein of 1,084 aa, which is approximately half the size of the full-length ABC1 protein. The loss of a Mnl1 restriction site, which results from the deletion, was used to establish the genotype of the rest of the kindred. In summary, we report on the genomic organization of the human ABC1 gene and identify a frameshift mutation in the ABC1 gene of the index case of Tangier disease. These results will be useful in the future characterization of the structure and function of the ABC1 gene and the analysis of additional ABC1 mutations in patients with Tangier disease. PMID:10535983

  17. Effects of in vitro exposure to ivermectin and levamisole on the expression patterns of ABC transporters in Haemonchus contortus larvae

    Directory of Open Access Journals (Sweden)

    Ali Raza

    2016-08-01

    Full Text Available This study investigated the interaction of ATP binding cassette (ABC transport proteins with ivermectin (IVM and levamisole (LEV in larvae of susceptible and resistant isolates of Haemonchus contortus in vitro by measuring transcription patterns following exposure to these anthelmintics. Furthermore, we studied the consequences of drug exposure by measuring the sensitivity of L3 to subsequent exposure to higher drug concentrations using larval migration assays. The most highly transcribed transporter genes in both susceptible and resistant L3 were pgp-9.3, abcf-1, mrp-5, abcf-2, pgp-3, and pgp-10. The resistant isolate showed significantly higher transcription of pgp-1, pgp-9.1 and pgp-9.2 compared to the susceptible isolate. Five P-gp genes and the haf-6 gene showed significantly higher transcription (up to 12.6-fold after 3 h exposure to IVM in the resistant isolate. Similarly, five P-gp genes, haf-6 and abcf-1 were transcribed at significantly higher levels (up to 10.3-fold following 3 h exposure to LEV in this isolate. On the other hand, there were no significant changes in transcriptional patterns of all transporter genes in the susceptible isolate following 3 and 6 h exposure to IVM or LEV. In contrast to these isolate-specific transcription changes, both isolates showed an increase in R-123 efflux following exposure to the drugs, suggesting that the drugs stimulated activity of existing transporter proteins in both isolates. Exposure of resistant larvae to IVM or LEV resulted, in some instances, in an increase in the proportion of the population able to migrate at the highest IVM concentrations in subsequent migration assays. The significant increase in transcription of some ABC transporter genes following 3 h exposure to both IVM and LEV in the resistant isolate only, suggests that an ability to rapidly upregulate protective pathways in response to drugs may be a component of the resistance displayed by this isolate.

  18. ABC Technology Development Program

    International Nuclear Information System (INIS)

    1994-01-01

    The Accelerator-Based Conversion (ABC) facility will be designed to accomplish the following mission: 'Provide a weapon's grade plutonium disposition capability in a safe, economical, and environmentally sound manner on a prudent schedule for [50] tons of weapon's grade plutonium to be disposed on in [20] years.' This mission is supported by four major objectives: provide a reliable plutonium disposition capability within the next [15] years; provide a level of safety and of safety assurance that meets or exceeds that afforded to the public by modern commercial nuclear power plants; meet or exceed all applicable federal, state, and local regulations or standards for environmental compliance; manage the program in a cost effective manner. The ABC Technology Development Program defines the technology development activities that are required to accomplish this mission. The technology development tasks are related to the following topics: blanket system; vessel systems; reactivity control systems; heat transport system components; energy conversion systems; shutdown heat transport systems components; auxiliary systems; technology demonstrations - large scale experiments

  19. Inventory and general analysis of the ATP-binding cassette (ABC) gene superfamily in maize (Zea mays L.).

    Science.gov (United States)

    Pang, Kaiyuan; Li, Yanjiao; Liu, Menghan; Meng, Zhaodong; Yu, Yanli

    2013-09-10

    The metabolic functions of ATP-binding cassette (or ABC) proteins, one of the largest families of proteins presented in all organisms, have been investigated in many protozoan, animal and plant species. To facilitate more systematic and complicated studies on maize ABC proteins in the future, we present the first complete inventory of these proteins, including 130 open reading frames (ORFs), and provide general descriptions of their classifications, basic structures, typical functions, evolution track analysis and expression profiles. The 130 ORFs were assigned to eight subfamilies based on their structures and homological features. Five of these subfamilies consist of 109 proteins, containing transmembrane domains (TM) performing as transporters. The rest three subfamilies contain 21 soluble proteins involved in various functions other than molecular transport. A comparison of ABC proteins among nine selected species revealed either convergence or divergence in each of the ABC subfamilies. Generally, plant genomes contain far more ABC genes than animal genomes. The expression profiles and evolution track of each maize ABC gene were further investigated, the results of which could provide clues for analyzing their functions. Quantitative real-time polymerase chain reaction experiments (PCR) were conducted to detect induced expression in select ABC genes under several common stresses. This investigation provides valuable information for future research on stress tolerance in plants and potential strategies for enhancing maize production under stressful conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. On transport mechanisms in solar cells involving organic semiconductors

    OpenAIRE

    Nolasco Montaño, Jairo César

    2011-01-01

    The knowledge of transport mechanisms in solar cells is useful to determine electrical losses. In my doctoral thesis we studied the transport mechanisms in solar cells involving organic semiconductors. We show that models which have been used to study amorphous inorganic solar cells can be applied on organic ones. We conclude that: multitunelling capture emission and tunelling-enhanced interface recombination mechanisms contribute to the dark current characteristics in P3HT/Si, Pc/C60 and P3H...

  1. RNA-seq analysis of the effect of kanamycin and the ABC transporter AtWBC19 on Arabidopsis thaliana seedlings reveals changes in metal content.

    Directory of Open Access Journals (Sweden)

    Ayalew Mentewab

    Full Text Available Plants are exposed to antibiotics produced by soil microorganisms, but little is known about their responses at the transcriptional level. Likewise, few endogenous mechanisms of antibiotic resistance have been reported. The Arabidopsis thaliana ATP Binding Cassette (ABC transporter AtWBC19 (ABCG19 is known to confer kanamycin resistance, but the exact mechanism of resistance is not well understood. Here we examined the transcriptomes of control seedlings and wbc19 mutant seedlings using RNA-seq analysis. Exposure to kanamycin indicated changes in the organization of the photosynthetic apparatus, metabolic fluxes and metal uptake. Elemental analysis showed a 60% and 80% reduction of iron uptake in control and wbc19 mutant seedlings respectively, upon exposure to kanamycin. The drop in iron content was accompanied by the upregulation of the gene encoding for FERRIC REDUCTION OXIDASE 6 (FRO6 in mutant seedlings but not by the differential expression of other transport genes known to be induced by iron deficiency. In addition, wbc19 mutants displayed a distinct expression profile in the absence of kanamycin. Most notably the expression of several zinc ion binding proteins, including ZINC TRANSPORTER 1 PRECURSOR (ZIP1 was increased, suggesting abnormal zinc uptake. Elemental analysis confirmed a 50% decrease of zinc content in wbc19 mutants. Thus, the antibiotic resistance gene WBC19 appears to also have a role in zinc uptake.

  2. 75 FR 49549 - ABC & D Recycling, Inc.-Lease and Operation Exemption-a Line of Railroad in Ware, MA

    Science.gov (United States)

    2010-08-13

    ... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35397] ABC & D Recycling, Inc.--Lease and Operation Exemption--a Line of Railroad in Ware, MA ABC & D Recycling, Inc. (ABC & D...\\ The line is currently operated by the Massachusetts Central Railroad Corporation.\\2\\ \\1\\ ABC & D...

  3. Preliminary time-of-flight neutron diffraction studies of Escherichia coli ABC transport receptor phosphate-binding protein at the Protein Crystallography Station.

    Science.gov (United States)

    Sippel, K H; Bacik, J; Quiocho, F A; Fisher, S Z

    2014-06-01

    Inorganic phosphate is an essential molecule for all known life. Organisms have developed many mechanisms to ensure an adequate supply, even in low-phosphate conditions. In prokaryotes phosphate transport is instigated by the phosphate-binding protein (PBP), the initial receptor for the ATP-binding cassette (ABC) phosphate transporter. In the crystal structure of the PBP-phosphate complex, the phosphate is completely desolvated and sequestered in a deep cleft and is bound by 13 hydrogen bonds: 12 to protein NH and OH donor groups and one to a carboxylate acceptor group. The carboxylate plays a key recognition role by accepting a phosphate hydrogen. PBP phosphate affinity is relatively consistent across a broad pH range, indicating the capacity to bind monobasic (H2PO4-) and dibasic (HPO4(2-)) phosphate; however, the mechanism by which it might accommodate the second hydrogen of monobasic phosphate is unclear. To answer this question, neutron diffraction studies were initiated. Large single crystals with a volume of 8 mm3 were grown and subjected to hydrogen/deuterium exchange. A 2.5 Å resolution data set was collected on the Protein Crystallography Station at the Los Alamos Neutron Science Center. Initial refinement of the neutron data shows significant nuclear density, and refinement is ongoing. This is the first report of a neutron study from this superfamily.

  4. The Absence of the Transcription Factor Yrr1p, Identified from Comparative Genome Profiling, Increased Vanillin Tolerance Due to Enhancements of ABC Transporters Expressing, rRNA Processing and Ribosome Biogenesis in Saccharomyces cerevisiae.

    Science.gov (United States)

    Wang, Xinning; Liang, Zhenzhen; Hou, Jin; Shen, Yu; Bao, Xiaoming

    2017-01-01

    Enhancing the tolerance of Saccharomyces cerevisiae to inhibitors derived from lignocellulose is conducive to producing biofuel and chemicals using abundant lignocellulosic materials. Vanillin is a major type of phenolic inhibitor in lignocellulose hydrolysates for S. cerevisiae . In the present work, the factors beneficial to vanillin resistance in yeast were identified from the vanillin-resistant strain EMV-8, which was derived from strain NAN-27 by adaptive evolution. We found 450 SNPs and 44 genes with InDels in the vanillin-tolerant strain EMV-8 by comparing the genome sequences of EMV-8 and NAN-27. To investigate the effects of InDels, InDels were deleted in BY4741, respectively. We demonstrated that the deletion of YRR1 improved vanillin tolerance of strain. In the presence of 6 mM vanillin, deleting YRR1 increase the maximum specific growth rate and the vanillin consumption rate by 142 and 51%, respectively. The subsequent transcriptome analysis revealed that deleting YRR1 resulted in changed expression of over 200 genes in the presence of 5 mM vanillin. The most marked changes were the significant up-regulation of the dehydrogenase ADH7 , several ATP-binding cassette (ABC) transporters, and dozens of genes involved in ribosome biogenesis and rRNA processing. Coincidently, the crude enzyme solution of BY4741( yrr1 Δ) exhibited higher NADPH-dependent vanillin reduction activity than control. In addition, overexpressing the ABC transporter genes PDR5, YOR1 , and SNQ2 , as well as the RNA helicase gene DBP2 , increased the vanillin tolerance of strain. Interestingly, unlike the marked changes we mentioned above, under vanillin-free conditions, there are only limited transcriptional differences between wildtype and yrr1 Δ. This indicated that vanillin might act as an effector in Yrr1p-related regulatory processes. The new findings of the relationship between YRR1 and vanillin tolerance, as well as the contribution of rRNA processing and ribosome biogenesis to

  5. Genes Involved in the Biosynthesis and Transport of Acinetobactin in

    Directory of Open Access Journals (Sweden)

    Tarik Hasan

    2015-03-01

    Full Text Available Pathogenic bacteria survive in iron-limited host environments by using several iron acquisition mechanisms. Acinetobacter baumannii, causing serious infections in compromised patients, produces an iron-chelating molecule, called acinetobactin, which is composed of equimolar quantities of 2,3-dihydroxybenzoic acid (DHBA, L-threonine, and N-hydroxyhistamine, to compete with host cells for iron. Genes that are involved in the production and transport of acinetobactin are clustered within the genome of A. baumannii. A recent study showed that entA, located outside of the acinetobactin gene cluster, plays important roles in the biosynthesis of the acinetobactin precursor DHBA and in bacterial pathogenesis. Therefore, understanding the genes that are associated with the biosynthesis and transport of acinetobactin in the bacterial genome is required. This review is intended to provide a general overview of the genes in the genome of A. baumannii that are required for acinetobactin biosynthesis and transport.

  6. Integrated Transport Planning Framework Involving Combined Utility Regret Approach

    DEFF Research Database (Denmark)

    Wang, Yang; Monzon, Andres; Di Ciommo, Floridea

    2014-01-01

    in a framework for integrated transport planning. The framework consisted of a two-round Delphi survey, integrated land use and transport model for Madrid, and multicriteria analysis. Results show that (a) the regret-based ranking has a similar mean but larger variance than the utility-based ranking does, (b......Sustainable transport planning requires an integrated approach involving strategic planning, impact analysis, and multicriteria evaluation. This study aimed at relaxing the utility-based decision-making assumption by newly embedding anticipated-regret and combined utility regret decision mechanisms......-based multicriteria analyses result in different rankings of policy packages, and (e) the combined utility regret ranking is more informative compared with the utility-based or the regret-based ranking....

  7. Involvement of NRAMP1 from Arabidopsis thaliana in iron transport.

    Science.gov (United States)

    Curie, C; Alonso, J M; Le Jean, M; Ecker, J R; Briat, J F

    2000-05-01

    Nramp genes code for a widely distributed class of proteins involved in a variety of processes, ranging from the control of susceptibility to bacterial infection in mammalian cells and taste behaviour in Drosophila to manganese uptake in yeast. Some of the NRAMP proteins in mammals and in yeast are capable of transporting metal ions, including iron. In plants, iron transport was shown to require a reduction/Fe(II) transport system. In Arabidopsis thaliana this process involves the IRT1 and Fro2 genes. Here we report the sequence of five NRAMP proteins from A. thaliana. Sequence comparison suggests that there are two classes of NRAMP proteins in plants: A. thaliana (At) NRAMP1 and Oriza sativa (Os) NRAMP1 and 3 (two rice isologues) represent one class, and AtNRAMP2-5 and OsNRAMP2 the other. AtNramp1 and OsNramp1 are able to complement the fet3fet4 yeast mutant defective both in low- and high-affinity iron transports, whereas AtNramp2 and OsNramp2 fail to do so. In addition, AtNramp1 transcript, but not AtNramp2 transcript, accumulates in response to iron deficiency in roots but not in leaves. Finally, overexpression of AtNramp1 in transgenic A. thaliana plants leads to an increase in plant resistance to toxic iron concentration. Taken together, these results demonstrate that AtNramp1 participates in the control of iron homoeostasis in plants.

  8. Emergency response planning for transport accidents involving radioactive materials

    International Nuclear Information System (INIS)

    1982-03-01

    The document presents a basic discussion of the various aspects and philosophies of emergency planning and preparedness along with a consideration of the problems which might be encountered in a transportation accident involving a release of radioactive materials. Readers who are responsible for preparing emergency plans and procedures will have to decide on how best to apply this guidance to their own organizational structures and will also have to decide on an emergency planning and preparedness philosophy suitable to their own situations

  9. ABC Kinga kauplused = ABC King shoe stores

    Index Scriptorium Estoniae

    2011-01-01

    Tallinnas Kristiine keskuses, Tartu Kaubamajas ja Pärnus Port Artur 2 asuvate ABC Kinga kaupluste sisekujundusest. Sisearhitekid Andres Labi ja Janno Roos (Ruumilabor OÜ), loetletud nende ühiselt tehtud töid

  10. Characterization of a lactose-responsive promoter of ATP-binding cassette (ABC) transporter gene from Lactobacillus acidophilus 05-172.

    Science.gov (United States)

    Zeng, Zhu; Zuo, Fanglei; Yu, Rui; Zhang, Bo; Ma, Huiqin; Chen, Shangwu

    2017-09-01

    A novel lactose-responsive promoter of the ATP-binding cassette (ABC) transporter gene Lba1680 of Lactobacillus acidophilus strain 05-172 isolated from a traditionally fermented dairy product koumiss was characterized. In L. acidophilus 05-172, expression of Lba1680 was induced by lactose, with lactose-induced transcription of Lba1680 being 6.1-fold higher than that induced by glucose. This is in contrast to L. acidophilus NCFM, a strain isolated from human feces, in which expression of Lba1680 and Lba1679 is induced by glucose. Both gene expression and enzyme activity assays in L. paracasei transformed with a vector containing the inducible Lba1680 promoter (PLba1680) of strain 05-172 and a heme-dependent catalase gene as reporter confirmed that PLba1680 is specifically induced by lactose. Its regulatory expression could not be repressed by glucose, and was independent of cAMP receptor protein. This lactose-responsive promoter might be used in the expression of functional genes in L. paracasei incorporated into a lactose-rich environment, such as dairy products. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. The ABC model of recombination reinterpreted: Impact on understanding carrier transport and efficiency droop in InGaN/GaN light emitting diodes

    Science.gov (United States)

    Hopkins, M. A.; Allsopp, D. W. E.; Kappers, M. J.; Oliver, R. A.; Humphreys, C. J.

    2017-12-01

    The efficiency of light emitting diodes (LEDs) remains a topic of great contemporary interest due to their potential to reduce the amount of energy consumed in lighting. The current consensus is that electrons and holes distribute themselves through the emissive region by a drift-diffusion process which results in a highly non-uniform distribution of the light emission and can reduce efficiency. In this paper, the measured variations in the external quantum efficiency of a range of InGaN/GaN LEDs with different numbers of quantum wells (QWs) are shown to compare closely with the predictions of a revised ABC model, in which it is assumed that the electrically injected electrons and holes are uniformly distributed through the multi-quantum well (MQW) region, or nearly so, and hence carrier recombination occurs equally in all the quantum wells. The implications of the reported results are that drift-diffusion plays a far lesser role in cross-well carrier transport than previously thought; that the dominant cause of efficiency droop is intrinsic to the quantum wells and that reductions in the density of non-radiative recombination centers in the MQW would enable the use of more QWs and thereby reduce Auger losses by spreading carriers more evenly across a wider emissive region.

  12. ABC transporter PEN3/PDR8/ABCG36 interacts with calmodulin that, like PEN3, is required for Arabidopsis nonhost resistance.

    Science.gov (United States)

    Campe, Ruth; Langenbach, Caspar; Leissing, Franz; Popescu, George V; Popescu, Sorina C; Goellner, Katharina; Beckers, Gerold J M; Conrath, Uwe

    2016-01-01

    Nonhost resistance (NHR) is the most prevalent form of plant immunity. In Arabidopsis, NHR requires membrane-localized ATP-binding cassette (ABC) transporter PENETRATION (PEN) 3. Upon perception of pathogen-associated molecular patterns, PEN3 becomes phosphorylated, suggestive of PEN3 regulation by post-translational modification. Here, we investigated the PEN3 protein interaction network. We probed the Arabidopsis protein microarray AtPMA-5000 with the N-terminal cytoplasmic domain of PEN3. Several of the proteins identified to interact with PEN3 in vitro represent cellular Ca(2+) sensors, including calmodulin (CaM) 3, CaM7 and several CaM-like proteins, pointing to the importance of Ca(2+) sensing to PEN3-mediated NHR. We demonstrated co-localization of PEN3 and CaM7, and we confirmed PEN3-CaM interaction in vitro and in vivo by PEN3 pull-down with CaM Sepharose, CaM overlay assay and bimolecular fluorescence complementation. We also show that just like in pen3, NHR to the nonadapted fungal pathogens Phakopsora pachyrhizi and Blumeria graminis f.sp. hordei is compromised in the Arabidopsis cam7 and pen3 cam7 mutants. Our study discloses CaM7 as a PEN3-interacting protein crucial to Arabidopsis NHR and emphasizes the importance of Ca(2+) sensing to plant immunity. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  13. The function of the ATP-binding cassette (ABC) transporter ABCB1 is not susceptible to actin disruption

    NARCIS (Netherlands)

    Meszaros, Peter; Hummel, Ina; Klappe, Karin; Draghiciu, Oana; Hoekstra, Dick; Kok, Jan W.

    Previously we have shown that the activity of the multidrug transporter ABCC1 (multidrug resistance protein 1), and its localization in lipid rafts, depends on cortical actin (Hummel I, Klappe K, Ercan C, Kok JW. Mol. Pharm. 2011 79, 229-40). Here we show that the efflux activity of the ATP-binding

  14. Relative rates of amino acid import via the ABC transporter GlnPQ determine the growth performance of Lactococcus lactis

    NARCIS (Netherlands)

    Fulyani, Faizah; Schuurman-Wolters, Geesina; Slotboom, Dirk-Jan; Poolman, Bert

    The GlnPQ transporter from Lactococcus lactis has the remarkable feature of having two substrate-binding domains (SBD) fused to the N-terminus of the transmembrane domain (TMD), and thus four SBDs are present in the homodimeric complex. Although X-ray structures and ligand binding data are available

  15. RCN1/OsABCG5, an ATP-binding cassette (ABC) transporter, is required for hypodermal suberization of roots in rice (Oryza sativa).

    Science.gov (United States)

    Shiono, Katsuhiro; Ando, Miho; Nishiuchi, Shunsaku; Takahashi, Hirokazu; Watanabe, Kohtaro; Nakamura, Motoaki; Matsuo, Yuichi; Yasuno, Naoko; Yamanouchi, Utako; Fujimoto, Masaru; Takanashi, Hideki; Ranathunge, Kosala; Franke, Rochus B; Shitan, Nobukazu; Nishizawa, Naoko K; Takamure, Itsuro; Yano, Masahiro; Tsutsumi, Nobuhiro; Schreiber, Lukas; Yazaki, Kazufumi; Nakazono, Mikio; Kato, Kiyoaki

    2014-10-01

    Suberin is a complex polymer composed of aliphatic and phenolic compounds. It is a constituent of apoplastic plant interfaces. In many plant species, including rice (Oryza sativa), the hypodermis in the outer part of roots forms a suberized cell wall (the Casparian strip and/or suberin lamellae), which inhibits the flow of water and ions and protects against pathogens. To date, there is no genetic evidence that suberin forms an apoplastic transport barrier in the hypodermis. We discovered that a rice reduced culm number1 (rcn1) mutant could not develop roots longer than 100 mm in waterlogged soil. The mutated gene encoded an ATP-binding cassette (ABC) transporter named RCN1/OsABCG5. RCN1/OsABCG5 gene expression in the wild type was increased in most hypodermal and some endodermal roots cells under stagnant deoxygenated conditions. A GFP-RCN1/OsABCG5 fusion protein localized at the plasma membrane of the wild type. Under stagnant deoxygenated conditions, well suberized hypodermis developed in wild types but not in rcn1 mutants. Under stagnant deoxygenated conditions, apoplastic tracers (periodic acid and berberine) were blocked at the hypodermis in the wild type but not in rcn1, indicating that the apoplastic barrier in the mutant was impaired. The amount of the major aliphatic suberin monomers originating from C(28) and C(30) fatty acids or ω-OH fatty acids was much lower in rcn1 than in the wild type. These findings suggest that RCN1/OsABCG5 has a role in the suberization of the hypodermis of rice roots, which contributes to formation of the apoplastic barrier. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  16. The role of peroxisomal ABC transporters in the mouse adrenal gland: the loss of Abcd2 (ALDR), Not Abcd1 (ALD), causes oxidative damage.

    Science.gov (United States)

    Lu, Jyh-Feng; Barron-Casella, Emily; Deering, Rebecca; Heinzer, Ann K; Moser, Ann B; deMesy Bentley, Karen L; Wand, Gary S; C McGuinness, Martina; Pei, Zhengtong; Watkins, Paul A; Pujol, Aurora; Smith, Kirby D; Powers, James M

    2007-03-01

    X-linked adreno-leukodystrophy is a progressive, systemic peroxisomal disorder that primarily affects the adrenal cortex, as well as myelin and axons of the central nervous system. Marked phenotypic heterogeneity does not correlate with disease-causing mutations in ABCD1, which encodes a peroxisomal membrane protein that is a member of the ABC transmembrane transporter proteins. The precise physiological functions of ABCD1 and ABCD2, a closely related peroxisomal membrane half-transporter, are unknown. The abcd1 knockout mouse does not develop the inflammatory demyelination so typical and devastating in adreno-leukodystrophy, but it does display the same lamellae and lipid profiles in adrenocortical cells under the electron microscope as the human patients. The adrenocortical cells in the mouse also exhibit immunohistochemical evidence of oxidative stress at 12 weeks but no evidence of oxidative damage. To better understand the pathogenesis of this complex disease, we evaluate the adrenal lesion of the abcd1 knockout mouse as a function of normal aging, dietary or therapeutic manipulations, and abcd genotype. The loss of abcd2 causes oxidative stress in the adrenal at 12 weeks, as judged by increased immunoreactivity for the mitochondrial manganese superoxide dismutase, in both the inner cortex and medulla. The loss of abcd2 (n=20), but not abcd1 (n=27), results in the spontaneous and premature deposition of ceroid, a known end-product of oxidative damage, predominantly in adrenal medullary cells. These data indicate that the loss of abcd2 results in greater oxidative stress in murine adrenal cells than the loss of abcd1, providing a clue to its cellular function. We also find that the adrenocortical lesion of the abcd1 knockout mouse does not produce functional impairment at ten to nineteen months or overt hypocortisolism at any age, nor does it progress histologically; these and other data align this mouse model closer to human female heterozygotes than to male

  17. Enhancing the ABC Cross

    OpenAIRE

    Euske, K.J.; Vercio, Alan

    2007-01-01

    The purpose of the ABC Cross was to portray both a cost and process view of an organization as simply as possible. Unfortunately, the model’s simplified form does not capture the real value of activity-based costing (ABC) for cost accounting that emerged in the mid-1980s. Here we present several ABC models that can help functional and process managers make better decisions.

  18. Multidrug resistance mediated by ABC transporters in osteosarcoma cell lines: mRNA analysis and functional radiotracer studies

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Celia Maria Freitas [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal)]. E-mail: cgomes@ibili.uc.pt; van Paassen, Heidi [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Romeo, Salvatore [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Welling, Mick M. [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Feitsma, R.I.J. [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Abrunhosa, Antero J. [Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal); Botelho, M. Filomena [Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal); Hogendoorn, Pancras C.W. [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Pauwels, Ernest [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Cleton-Jansen, Anne Marie [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands)

    2006-10-15

    Drug resistance remains a significant impediment to successful chemotherapy and constitutes a major prognostic factor in osteosarcoma (OS) patients. This study was designed to identify the role and prognostic significance of multidrug-resistance (MDR)-related transporters, such as multidrug resistance protein 1 (MDR1), multidrug-resistance-associated protein (MRP1) and breast-cancer-related protein (BCRP), in OS using cationic lipophilic radiotracers. We evaluated the chemosensitivity of four OS cell lines (Saos-2, 143B, MNNG/HOS and U-2OS) to doxorubicin (DOX), cisplatin (CIS) and methotrexate. The expression of MDR-related transporters was analyzed at mRNA level by quantitative polymerase chain reaction and at functional level by {sup 99m}Tc sestamibi and {sup 99m}Tc tetrofosmin. The effectiveness of MDR modulators [cyclosporin A (CsA) and imatinib] on transporter inhibition and on the reversal of resistance was also assessed. MNNG/HOS and U-2OS cells expressing high levels of MDR1 were highly resistant to DOX and showed reduced accumulation and higher efflux for radiotracers. Although MRP1 was uniformly expressed in all cells, only U-2OS was resistant to CIS. CsA restored sensitivity to DOX and CIS, and enhanced the accumulation and efflux half-life of radiotracers in MDR1-expressing cell lines. The chemosensitivity of OS cells to DOX was strongly dependent on mRNA MDR1 expression and could be circumvented by adding CsA. The kinetic parameters of radiotracers correlated with MDR1 expression levels, hence predicting DOX resistance. We concluded that sensitivity to chemotherapy is strongly dependent on the expression of MDR1 transporter and that radiotracer studies could prove clinically useful in predicting chemotherapy response and in evaluating the efficacy of MDR-reversing agents.

  19. An ABC transporter B family protein, ABCB19, is required for cytoplasmic streaming and gravitropism of the inflorescence stems.

    Science.gov (United States)

    Okamoto, Keishi; Ueda, Haruko; Shimada, Tomoo; Tamura, Kentaro; Koumoto, Yasuko; Tasaka, Masao; Morita, Miyo Terao; Hara-Nishimura, Ikuko

    2016-01-01

    A significant feature of plant cells is the extensive motility of organelles and the cytosol, which was originally defined as cytoplasmic streaming. We suggested previously that a three-way interaction between plant-specific motor proteins myosin XIs, actin filaments, and the endoplasmic reticulum (ER) was responsible for cytoplasmic streaming. (1) Currently, however, there are no reports of molecular components for cytoplasmic streaming other than the actin-myosin-cytoskeleton and ER-related proteins. In the present study, we found that elongated cells of inflorescence stems of Arabidopsis thaliana exhibit vigorous cytoplasmic streaming. Statistical analysis showed that the maximal velocity of plastid movements is 7.26 µm/s, which is much faster than the previously reported velocities of organelles. Surprisingly, the maximal velocity of streaming in the inflorescence stem cells was significantly reduced to 1.11 µm/s in an Arabidopsis mutant, abcb19-101, which lacks ATP BINDING CASSETTE SUBFAMILY B19 (ABCB19) that mediates the polar transport of the phytohormone auxin together with PIN-FORMED (PIN) proteins. Polar auxin transport establishes the auxin concentration gradient essential for plant development and tropisms. Deficiency of ABCB19 activity eventually caused enhanced gravitropic responses of the inflorescence stems and abnormally flexed inflorescence stems. These results suggest that ABCB19-mediated auxin transport plays a role not only in tropism regulation, but also in cytoplasmic streaming.

  20. Loss of AtPDR11, a plasma membrane-localized ABC transporter, confers paraquat tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Xi, Jing; Xu, Ping; Xiang, Cheng-Bin

    2012-03-01

    Paraquat is one of the most widely used herbicides in the world. However, no paraquat transporter has been isolated in plants. Here, we describe paraquat-tolerant mutant pqt24-1, isolated from an activation-tagging library on the basis of its tolerance to 2 μm paraquat in the seedling stage. Molecular analysis revealed that the T-DNA was inserted in the 13th exon of At1g66950, which encodes AtPDR11, a member of the ATP-binding cassette transporter superfamily. As a result, AtPDR11 was knocked out in the mutant. Loss-of-function mutations of AtPDR11 led to reduced paraquat accumulation in plant cells. In addition, the AtPDR11 protein was specifically localized in the plasmalemma, suggesting AtPDR11 as a potential transporter of paraquat. This conclusion was supported by kinetic analysis of paraquat import. Further studies showed that the transcript level of AtPDR11 could be strongly induced by paraquat and other abiotic stresses including H(2) O(2) , indicating possible up-regulation of AtPDR11 expression by oxidative stress signaling. Thus, our data suggest that paraquat is an opportunistic substrate of AtPDR11 and the enhanced paraquat tolerance of pqt24-1 is due to reduced uptake of paraquat into plant cells. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  1. An ABC transporter B family protein, ABCB19, is required for cytoplasmic streaming and gravitropism of the inflorescence stems

    Science.gov (United States)

    Okamoto, Keishi; Ueda, Haruko; Shimada, Tomoo; Tamura, Kentaro; Koumoto, Yasuko; Tasaka, Masao; Morita, Miyo Terao; Hara-Nishimura, Ikuko

    2016-01-01

    Abstract A significant feature of plant cells is the extensive motility of organelles and the cytosol, which was originally defined as cytoplasmic streaming. We suggested previously that a three-way interaction between plant-specific motor proteins myosin XIs, actin filaments, and the endoplasmic reticulum (ER) was responsible for cytoplasmic streaming.1 Currently, however, there are no reports of molecular components for cytoplasmic streaming other than the actin-myosin-cytoskeleton and ER-related proteins. In the present study, we found that elongated cells of inflorescence stems of Arabidopsis thaliana exhibit vigorous cytoplasmic streaming. Statistical analysis showed that the maximal velocity of plastid movements is 7.26 µm/s, which is much faster than the previously reported velocities of organelles. Surprisingly, the maximal velocity of streaming in the inflorescence stem cells was significantly reduced to 1.11 µm/s in an Arabidopsis mutant, abcb19-101, which lacks ATP BINDING CASSETTE SUBFAMILY B19 (ABCB19) that mediates the polar transport of the phytohormone auxin together with PIN-FORMED (PIN) proteins. Polar auxin transport establishes the auxin concentration gradient essential for plant development and tropisms. Deficiency of ABCB19 activity eventually caused enhanced gravitropic responses of the inflorescence stems and abnormally flexed inflorescence stems. These results suggest that ABCB19-mediated auxin transport plays a role not only in tropism regulation, but also in cytoplasmic streaming. PMID:26337543

  2. Tritium Suicide Selection Identifies Proteins Involved in the Uptake and Intracellular Transport of Sterols in Saccharomyces cerevisiae▿

    Science.gov (United States)

    Sullivan, David P.; Georgiev, Alexander; Menon, Anant K.

    2009-01-01

    Sterol transport between the plasma membrane (PM) and the endoplasmic reticulum (ER) occurs by a nonvesicular mechanism that is poorly understood. To identify proteins required for this process, we isolated Saccharomyces cerevisiae mutants with defects in sterol transport. We used Upc2-1 cells that have the ability to take up sterols under aerobic conditions and exploited the observation that intracellular accumulation of exogenously supplied [3H]cholesterol in the form of [3H]cholesteryl ester requires an intact PM-ER sterol transport pathway. Upc2-1 cells were mutagenized using a transposon library, incubated with [3H]cholesterol, and subjected to tritium suicide selection to isolate mutants with a decreased ability to accumulate [3H]cholesterol. Many of the mutants had defects in the expression and trafficking of Aus1 and Pdr11, PM-localized ABC transporters that are required for sterol uptake. Through characterization of one of the mutants, a new role was uncovered for the transcription factor Mot3 in controlling expression of Aus1 and Pdr11. A number of mutants had transposon insertions in the uncharacterized Ydr051c gene, which we now refer to as DET1 (decreased ergosterol transport). These mutants expressed Aus1 and Pdr11 normally but were severely defective in the ability to accumulate exogenously supplied cholesterol. The transport of newly synthesized sterols from the ER to the PM was also defective in det1Δ cells. These data indicate that the cytoplasmic protein encoded by DET1 is involved in intracellular sterol transport. PMID:19060182

  3. The human peroxisomal ABC half transporter ALDP functions as a homodimer and accepts acyl-CoA esters

    NARCIS (Netherlands)

    van Roermund, Carlo W. T.; Visser, Wouter F.; Ijlst, Lodewijk; van Cruchten, Arno; Boek, Maxim; Kulik, Wim; Waterham, Hans R.; Wanders, Ronald J. A.

    2008-01-01

    Peroxisomes play a major role in human cellular lipid metabolism, including the beta-oxidation of fatty acids. The most frequent peroxisomal disorder is X-linked adrenoleukodystrophy (X-ALD), which is caused by mutations in the ABCD1 gene. The protein involved, called ABCD1, or alternatively ALDP,

  4. A Putative ABC Transporter Permease is Necessary For Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa Under Aerobic, Anaerobic, Planktonic or Biofilm Conditions

    Directory of Open Access Journals (Sweden)

    Cameron eMcDaniel

    2016-04-01

    Full Text Available Pseudomonas aeruginosa (PA is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite (A-NO2-, pH 6.5 at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to A-NO2-. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to A-NO2-, but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin and chloramphenicol, respectively. Treatment of bacteria with A-NO2- plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 25 mM (aerobic, 15 mM (anaerobic A-NO2- and EDTA (1 mM, aerobic, anaerobic, respectively. Most importantly, the PA4455 mutant was also sensitive to A-NO2- in biofilms. A-NO2- sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, A-NO2- as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.

  5. A Putative ABC Transporter Permease Is Necessary for Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa under Aerobic and Anaerobic Planktonic and Biofilm Conditions.

    Science.gov (United States)

    McDaniel, Cameron; Su, Shengchang; Panmanee, Warunya; Lau, Gee W; Browne, Tristan; Cox, Kevin; Paul, Andrew T; Ko, Seung-Hyun B; Mortensen, Joel E; Lam, Joseph S; Muruve, Daniel A; Hassett, Daniel J

    2016-01-01

    Pseudomonas aeruginosa (PA) is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite ([Formula: see text], pH 6.5) at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to [Formula: see text]. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to [Formula: see text], but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with [Formula: see text] plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM [Formula: see text], and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to [Formula: see text] in biofilms. [Formula: see text] sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM) that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, [Formula: see text] as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.

  6. The cystic-fibrosis-associated ΔF508 mutation confers post-transcriptional destabilization on the C. elegans ABC transporter PGP-3

    Directory of Open Access Journals (Sweden)

    Liping He

    2012-11-01

    Membrane proteins make up ∼30% of the proteome. During the early stages of maturation, this class of proteins can experience localized misfolding in distinct cellular compartments, such as the cytoplasm, endoplasmic reticulum (ER lumen and ER membrane. ER quality control (ERQC mechanisms monitor folding and determine whether a membrane protein is appropriately folded or is misfolded and warrants degradation. ERQC plays crucial roles in human diseases, such as cystic fibrosis, in which deletion of a single amino acid (F508 results in the misfolding and degradation of the cystic fibrosis transmembrane conductance regulator (CFTR Cl– channel. We introduced the ΔF508 mutation into Caenorhabditis elegans PGP-3, a 12-transmembrane ABC transporter with 15% identity to CFTR. When expressed in intestinal epithelial cells, PGP-3wt was stable and efficiently trafficked to the apical plasma membrane through a COPII-dependent mechanism. However, PGP-3ΔF508 was post-transcriptionally destabilized, resulting in reduced total and apical membrane protein levels. Genetic or physiological activation of the osmotic stress response pathway, which causes accumulation of the chemical chaperone glycerol, stabilized PGP-3ΔF508. Efficient degradation of PGP-3ΔF508 required the function of several C. elegans ER-associated degradation (ERAD homologs, suggesting that destabilization occurs through an ERAD-type mechanism. Our studies show that the ΔF508 mutation causes post-transcriptional destabilization and degradation of PGP-3 in C. elegans epithelial cells. This model, combined with the power of C. elegans genetics, provides a new opportunity to genetically dissect metazoan ERQC.

  7. The ABC and AUSSAT.

    Science.gov (United States)

    McGarritty, Ian

    1985-01-01

    Discusses the Australian Broadcasting Corporation's (ABC) utilization of the AUSSAT telecommunications satellite to extend its television and radio transmission range to reach remote Australian audiences; the satellite's program gathering and interchange capabilities; and ABC's generation of other benefits to offset cost of satellite services.…

  8. Impaired phloem loading in zmsweet13a,b,c sucrose transporter triple knock-out mutants in Zea mays.

    Science.gov (United States)

    Bezrutczyk, Margaret; Hartwig, Thomas; Horschman, Marc; Char, Si Nian; Yang, Jinliang; Yang, Bing; Frommer, Wolf B; Sosso, Davide

    2018-04-01

    Crop yield depends on efficient allocation of sucrose from leaves to seeds. In Arabidopsis, phloem loading is mediated by a combination of SWEET sucrose effluxers and subsequent uptake by SUT1/SUC2 sucrose/H + symporters. ZmSUT1 is essential for carbon allocation in maize, but the relative contribution to apoplasmic phloem loading and retrieval of sucrose leaking from the translocation path is not known. Here we analysed the contribution of SWEETs to phloem loading in maize. We identified three leaf-expressed SWEET sucrose transporters as key components of apoplasmic phloem loading in Zea mays L. ZmSWEET13 paralogues (a, b, c) are among the most highly expressed genes in the leaf vasculature. Genome-edited triple knock-out mutants were severely stunted. Photosynthesis of mutants was impaired and leaves accumulated high levels of soluble sugars and starch. RNA-seq revealed profound transcriptional deregulation of genes associated with photosynthesis and carbohydrate metabolism. Genome-wide association study (GWAS) analyses may indicate that variability in ZmSWEET13s correlates with agronomical traits, especifically flowering time and leaf angle. This work provides support for cooperation of three ZmSWEET13s with ZmSUT1 in phloem loading in Z. mays. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  9. Dual fluorescent labelling of the human malaria parasite Plasmodium falciparum for the analysis of the ABC type transporter pfmdr2

    Directory of Open Access Journals (Sweden)

    Rosental Benyamin

    2012-11-01

    Full Text Available Abstract Background The study of the Plasmodium falciparum heavy metal transporter gene pfmdr2 employed radioactive labelled heavy metal. As the use of radioactive isotopes shrank considerably during the last few years, resulting in the cessation of the production of some isotopes, amongst them Cadmium109 which was used for that purpose, a different approach had to be developed. Herein, a dual fluorescent labelling of heavy metals accumulation in the P. falciparum parasite is proposed as an alternative to the use of radioactive labelled heavy metals. Methods Plasmodium falciparum Cd resistant and sensitive strains at the trophozoite stage were used in this study. The cells were cultured at different CdCl2 concentrations and for different time periods followed by staining of the infected red blood cells with Fluo-3/AM for Cd detection and Hoechst 33342 for parasite DNA labelling. The fluorescent analysis was done by flow cytometry and confocal microscopy. Results The results show that the sensitive strain has a higher Fluo-3/AM fluorescence in a Cd concentration and time dependent manner, whereas in the resistant strain Fluo-3/AM fluorescence levels were negligible and increased only at high concentrations of Cd and at long incubation periods, but to a much lesser extent than the sensitive strain. No Cd uptake is observed in uninfected red blood cells populations originating from cultures infected with either sensitive or resistant strain. In addition, confocal microscopy overlay of Fluo-3/AM and Hoechst staining shows that the Cd metal accumulates in the parasite itself. Conclusions The dual fluorescent labelling is a valid method for detecting heavy metal accumulation in P. falciparum. Furthermore, in contrast to the use of radioactive labelled heavy metal, the fluorescent labelling enables us to differentiate between the different populations existing in a P. falciparum infected red blood cells cultures and thus actually study a phenomenon at

  10. Rhizobium leguminosarum has a second general amino acid permease with unusually broad substrate specificity and high similarity to branched-chain amino acid transporters (Bra/LIV) of the ABC family.

    Science.gov (United States)

    Hosie, A H F; Allaway, D; Galloway, C S; Dunsby, H A; Poole, P S

    2002-08-01

    Amino acid uptake by Rhizobium leguminosarum is dominated by two ABC transporters, the general amino acid permease (Aap) and the branched-chain amino acid permease (Bra(Rl)). Characterization of the solute specificity of Bra(Rl) shows it to be the second general amino acid permease of R. leguminosarum. Although Bra(Rl) has high sequence identity to members of the family of hydrophobic amino acid transporters (HAAT), it transports a broad range of solutes, including acidic and basic polar amino acids (L-glutamate, L-arginine, and L-histidine), in addition to neutral amino acids (L-alanine and L-leucine). While amino and carboxyl groups are required for transport, solutes do not have to be alpha-amino acids. Consistent with this, Bra(Rl) is the first ABC transporter to be shown to transport gamma-aminobutyric acid (GABA). All previously identified bacterial GABA transporters are secondary carriers of the amino acid-polyamine-organocation (APC) superfamily. Also, transport by Bra(Rl) does not appear to be stereospecific as D amino acids cause significant inhibition of uptake of L-glutamate and L-leucine. Unlike all other solutes tested, L-alanine uptake is not dependent on solute binding protein BraC(Rl). Therefore, a second, unidentified solute binding protein may interact with the BraDEFG(Rl) membrane complex during L-alanine uptake. Overall, the data indicate that Bra(Rl) is a general amino acid permease of the HAAT family. Furthermore, Bra(Rl) has the broadest solute specificity of any characterized bacterial amino acid transporter.

  11. The Arabidopsis Peroxisomal ABC Transporter, Comatose, Complements the Saccharomyces cerevisiae pxa1 pxa2Δ Mutant for Metabolism of Long-chain Fatty Acids and Exhibits Fatty Acyl-CoA-stimulated ATPase Activity*

    Science.gov (United States)

    Nyathi, Yvonne; De Marcos Lousa, Carine; van Roermund, Carlo W.; Wanders, Ronald J. A.; Johnson, Barbara; Baldwin, Stephen A.; Theodoulou, Frederica L.; Baker, Alison

    2010-01-01

    The Arabidopsis ABC transporter Comatose (CTS; AtABCD1) is required for uptake into the peroxisome of a wide range of substrates for β-oxidation, but it is uncertain whether CTS itself is the transporter or if the transported substrates are free acids or CoA esters. To establish a system for its biochemical analysis, CTS was expressed in Saccharomyces cerevisiae. The plant protein was correctly targeted to yeast peroxisomes, was assembled into the membrane with its nucleotide binding domains in the cytosol, and exhibited basal ATPase activity that was sensitive to aluminum fluoride and abrogated by mutation of a conserved Walker A motif lysine residue. The yeast pxa1 pxa2Δ mutant lacks the homologous peroxisomal ABC transporter and is unable to grow on oleic acid. Consistent with its exhibiting a function in yeast akin to that in the plant, CTS rescued the oleate growth phenotype of the pxa1 pxa2Δ mutant, and restored β-oxidation of fatty acids with a range of chain lengths and varying degrees of desaturation. When expressed in yeast peroxisomal membranes, the basal ATPase activity of CTS could be stimulated by fatty acyl-CoAs but not by fatty acids. The implications of these findings for the function and substrate specificity of CTS are discussed. PMID:20659892

  12. The Arabidopsis peroxisomal ABC transporter, comatose, complements the Saccharomyces cerevisiae pxa1 pxa2Delta mutant for metabolism of long-chain fatty acids and exhibits fatty acyl-CoA-stimulated ATPase activity.

    Science.gov (United States)

    Nyathi, Yvonne; De Marcos Lousa, Carine; van Roermund, Carlo W; Wanders, Ronald J A; Johnson, Barbara; Baldwin, Stephen A; Theodoulou, Frederica L; Baker, Alison

    2010-09-24

    The Arabidopsis ABC transporter Comatose (CTS; AtABCD1) is required for uptake into the peroxisome of a wide range of substrates for β-oxidation, but it is uncertain whether CTS itself is the transporter or if the transported substrates are free acids or CoA esters. To establish a system for its biochemical analysis, CTS was expressed in Saccharomyces cerevisiae. The plant protein was correctly targeted to yeast peroxisomes, was assembled into the membrane with its nucleotide binding domains in the cytosol, and exhibited basal ATPase activity that was sensitive to aluminum fluoride and abrogated by mutation of a conserved Walker A motif lysine residue. The yeast pxa1 pxa2Δ mutant lacks the homologous peroxisomal ABC transporter and is unable to grow on oleic acid. Consistent with its exhibiting a function in yeast akin to that in the plant, CTS rescued the oleate growth phenotype of the pxa1 pxa2Δ mutant, and restored β-oxidation of fatty acids with a range of chain lengths and varying degrees of desaturation. When expressed in yeast peroxisomal membranes, the basal ATPase activity of CTS could be stimulated by fatty acyl-CoAs but not by fatty acids. The implications of these findings for the function and substrate specificity of CTS are discussed.

  13. Rapportering med ABC modellen

    DEFF Research Database (Denmark)

    Wiese, Lars Ole

    2006-01-01

    I denne artikel diskuteres Activity Based Costing (ABC) som rapporterings-teknik for kunde profitabilitet. Der argumenteres for, at indtægtserhvervel-sen inkl. dens direkte omkostningsforbrug bør adskilles fra omkostnings-beskrivelsen til produktfremstilling. Dvs. der gennemføres en aktivitetsba......-seret rapportering for indtægter og en ABC model for omkostningsforbrug til produktfremstilling. Modellen er tilført logiske beslutningsobjekter (klas-sifikationer), som er opbygget niveaubaseret. Samtidigt føres belæg for, at ABC modellen bør baseres på logiske fordelinger til kalkulationsobjektet i stedet...

  14. Involvement of Multiple Transporters-mediated Transports in Mizoribine and Methotrexate Pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Teruo Murakami

    2012-08-01

    Full Text Available Mizoribine is administered orally and excreted into urine without being metabolized. Many research groups have reported a linear relationship between the dose and peak serum concentration, between the dose and AUC, and between AUC and cumulative urinary excretion of mizoribine. In contrast, a significant interindividual variability, with a small intraindividual variability, in oral bioavailability of mizoribine is also reported. The interindividual variability is mostly considered to be due to the polymophisms of transporter genes. Methotrexate (MTX is administered orally and/or by parenteral routes, depending on the dose. Metabolic enzymes and multiple transporters are involved in the pharmacokinetics of MTX. The oral bioavailability of MTX exhibits a marked interindividual variability and saturation with increase in the dose of MTX, with a small intraindividual variability, where the contribution of gene polymophisms of transporters and enzymes is suggested. Therapeutic drug monitoring of both mizoribine and MTX is expected to improve their clinical efficacy in the treatment of rheumatoid arthritis.

  15. 77 FR 53779 - Reports by Air Carriers on Incidents Involving Animals During Air Transport

    Science.gov (United States)

    2012-09-04

    ... Involving Animals During Air Transport AGENCY: Office of the Secretary (OST), Department of Transportation... period of an NPRM on the reporting of incidents involving animals during air transport that was published... animal during air transport. The NPRM proposed to: (1) Expand the reporting requirement to U.S. carriers...

  16. A putative amino acid ABC transporter substrate-binding protein, NMB1612, from Neisseria meningitidis, induces murine bactericidal antibodies against meningococci expressing heterologous NMB1612 proteins.

    Science.gov (United States)

    Hung, Miao-Chiu; Humbert, María Victoria; Laver, Jay R; Phillips, Renee; Heckels, John E; Christodoulides, Myron

    2015-08-26

    The nmb1612 (NEIS1533) gene encoding the ~27-kDa putative amino acid ATP-binding cassette (ABC) transporter, periplasmic substrate-binding protein from Neisseria meningitidis serogroup B (MenB) strain MC58 was cloned and expressed in Escherichia coli, and the purified recombinant (r)NMB1612 was used for animal immunization studies. Immunization of mice with rNMB1612 adsorbed to Al(OH)3 and in liposomes with and without MPLA, induced antiserum with bactericidal activity in an assay using baby rabbit complement, against the homologous strain MC58 (encoding protein representative of Allele 62) and killed heterologous strains encoding proteins of three other alleles (representative of Alleles 1, 64 and 68), with similar SBA titres. However, strain MC58 was not killed (titre bactericidal assay (hSBA) using anti-rNMB1612 sera, although another strain (MC168) expressing the same protein was killed (median titres of 16-64 in the hSBA). Analysis of the NMB1612 amino acid sequences from 4351 meningococcal strains in the pubmlst.org/Neisseria database and a collection of 13 isolates from colonized individuals and from patients, showed that antibodies raised against rNMB1612 could potentially kill at least 72% of the MenB strains in the complete sequence database. For MenB disease occurring specifically in the UK from 2013 to 2015, >91% of the isolates causing disease in this recent period expressed NMB1612 protein encoded by Allele 1 and could be potentially killed by sera raised to the recombinant antigen in the current study. The NMB1612 protein was surface-accessible and expressed by different meningococcal strains. In summary, the properties of (i) NMB1612 protein conservation and expression, (ii) limited amino acid sequence variation between proteins encoded by different alleles, and (iii) the ability of a recombinant protein to induce cross-strain bactericidal antibodies, would all suggest a promising antigen for consideration for inclusion in new meningococcal vaccines

  17. Identification of ABC transporter genes conferring combined pleuromutilin-lincosamide-streptogramin A resistance in bovine methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci.

    Science.gov (United States)

    Wendlandt, Sarah; Kadlec, Kristina; Feßler, Andrea T; Schwarz, Stefan

    2015-06-12

    The aim of this study was to investigate the genetic basis of combined pleuromutilin-lincosamide-streptogramin A resistance in 26 unrelated methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) from dairy cows suffering from mastitis. The 26 pleuromutilin-resistant staphylococcal isolates were screened for the presence of the genes vga(A), vga(B), vga(C), vga(E), vga(E) variant, sal(A), vmlR, cfr, lsa(A), lsa(B), lsa(C), and lsa(E) by PCR. None of the 26 isolates carried the genes vga(B), vga(C), vga(E), vga(E) variant, vmlR, cfr, lsa(A), lsa(B), or lsa(C). Two Staphylococcus haemolyticus and single Staphylococcus xylosus, Staphylococcus lentus, and Staphylococcus hominis were vga(A)-positive. Twelve S. aureus, two Staphylococcus warneri, as well as single S. lentus and S. xylosus carried the lsa(E) gene. Moreover, single S. aureus, S. haemolyticus, S. xylosus, and Staphylococcus epidermidis were positive for both genes, vga(A) and lsa(E). The sal(A) gene was found in a single Staphylococcus sciuri. All ABC transporter genes were located in the chromosomal DNA, except for a plasmid-borne vga(A) gene in the S. epidermidis isolate. The genetic environment of the lsa(E)-positive isolates was analyzed using previously described PCR assays. Except for the S. warneri and S. xylosus, all lsa(E)-positive isolates harbored a part of the previously described enterococcal multiresistance gene cluster. This is the first report of the novel lsa(E) gene in the aforementioned bovine CoNS species. This is also the first identification of the sal(A) gene in a S. sciuri from a case of bovine mastitis. Moreover, the sal(A) gene was shown to also confer pleuromutilin resistance. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Involvement of Agrobacterium tumefaciens Galacturonate Tripartite ATP-Independent Periplasmic (TRAP) Transporter GaaPQM in Virulence Gene Expression.

    Science.gov (United States)

    Zhao, Jinlei; Binns, Andrew N

    2016-02-15

    Monosaccharides capable of serving as nutrients for the soil bacterium Agrobacterium tumefaciens are also inducers of the vir regulon present in the tumor-inducing (Ti) plasmid of this plant pathogen. One such monosaccharide is galacturonate, the predominant monomer of pectin found in plant cell walls. This ligand is recognized by the periplasmic sugar binding protein ChvE, which interacts with the VirA histidine kinase that controls vir gene expression. Although ChvE is also a member of the ChvE-MmsAB ABC transporter involved in the utilization of many neutral sugars, it is not involved in galacturonate utilization. In this study, a putative tripartite ATP-independent periplasmic (TRAP) transporter, GaaPQM, is shown to be essential for the utilization of galacturonic acid; we show that residue R169 in the predicted sugar binding site of the GaaP is required for activity. The gene upstream of gaaPQM (gaaR) encodes a member of the GntR family of regulators. GaaR is shown to repress the expression of gaaPQM, and the repression is relieved in the presence of the substrate for GaaPQM. Moreover, GaaR is shown to bind putative promoter regions in the sequences required for galacturonic acid utilization. Finally, A. tumefaciens strains carrying a deletion of gaaPQM are more sensitive to galacturonate as an inducer of vir gene expression, while the overexpression of gaaPQM results in strains being less sensitive to this vir inducer. This supports a model in which transporter activity is crucial in ensuring that vir gene expression occurs only at sites of high ligand concentration, such as those at a plant wound site. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  19. Sulfur source-mediated transcriptional regulation of the rhlABC genes involved in biosurfactants production by Pseudomonas sp. strain AK6U.

    Science.gov (United States)

    Ismail, Wael; El Nayal, Ashraf M; Ramadan, Ahmed R; Abotalib, Nasser

    2014-01-01

    Despite the nutritional significance of sulfur, its influence on biosurfactants production has not been sufficiently studied. We investigated the expression of key biosurfactants production genes, rhlABC, in cultures of Pseudomonas sp. AK6U grown with inorganic or organic sulfur sources. AK6U grew with either inorganic sulfate (MgSO4), dibenzothiophene (DBT), or DBT-sulfone as a sole sulfur source in the presence of glucose as a carbon source. The AK6U cultures produced variable amounts of biosurfactants depending on the utilized sulfur source. Biosurfactants production profile of the DBT cultures was significantly different from that of the DBT-sulfone and inorganic sulfate cultures. The last two cultures were very similar in terms of biosurfactants productivity. Biosurfactants yield in the DBT cultures (1.3 g/L) was higher than that produced by the DBT-sulfone (0.5 g/L) and the inorganic sulfate (0.44 g/L) cultures. Moreover, the surface tension reduction in the DBT cultures (33 mN/m) was much stronger than that measured in the DBT-sulfone (58 mN/m) or inorganic sulfate (54 mN/m) cultures. RT-qPCR revealed variations in the expression levels of the rhlABC genes depending on the sulfur source. The DBT cultures had higher expression levels for the three genes as compared to the DBT-sulfone and inorganic sulfate cultures. There was no significant difference in the expression profiles between the DBT-sulfone and the MgSO4 cultures. The increased expression of rhlC in the DBT cultures is indicative for production of higher amounts of dirhamnolipids compared to the DBT-sulfone and inorganic sulfate cultures. The gene expression results were in good agreement with the biosurfactants production yields and surface tension measurements. The sulfur source mediates a fine-tuned mechanism of transcriptional regulation of biosurfactants production genes. Our findings can have an impact on industrial production of biosurfactants and other biotechnological processes like

  20. The role of the atypical kinases ABC1K7 and ABC1K8 in abscisic acid responses

    Directory of Open Access Journals (Sweden)

    Anna eManara

    2016-03-01

    Full Text Available The ABC1K family of atypical kinases (activity of bc1 complex kinase is represented in bacteria, archaea and eukaryotes. In plants they regulate diverse physiological processes in the chloroplasts and mitochondria, but their precise functions are poorly defined. ABC1K7 and ABC1K8 are probably involved in oxidative stress responses, isoprenyl lipid synthesis and distribution of iron within chloroplasts. Because reactive oxygen species take part in abscisic acid (ABA-mediated processes, we investigated the functions of ABC1K7 and ABC1K8 during germination, stomatal movement and leaf senescence. Both genes were upregulated by ABA treatment and some ABA-responsive physiological processes were affected in abc1k7 and abc1k8 mutants. Germination was more severely affected by ABA, osmotic stress and salt stress in the single and double mutants; the stomatal aperture was smaller in the mutants under standard growth conditions and was not further reduced by exogenous ABA application; ABA-induced senescence symptoms were more severe in the leaves of the single and double mutants compared to wild type leaves. Taken together, our results suggest that ABC1K7 and ABC1K8 might be involved in the cross-talk between ABA and ROS signaling.

  1. The role of transporters on drug therapy

    Directory of Open Access Journals (Sweden)

    . Ngatidjan

    2016-02-01

    Full Text Available ABSTRACT Pharmacodynamical studies showed that most drugs elicit their effects by acting on 3 kinds of protein molecules known as receptors, enzymes or transporters. Although their detail properties had not been explained for decades the roles of transporters in drug kinetics and dynamics has been well understood, even have been applied in the therapy. Transporters are classified into 2 major classes, the solute carriers (SLC and ATP-binding cassette (ABC families. SLC transporters do not possess ATP binding site property as those of ABC transporters. SLC transporters consist of 3 SLC subfamilies i.e. organic cation transporters (OCTs, organic anion transporters (OATs and organic anion transporting polypeptides (OATPs. In contrast, ABC transporters require ATP hydrolysis to transport substrate across cell membrane. Human ABC-transporters consist of ABCA1- 13, ABCB1-11, ABCC1-12, ABCD1-4, ABCE1, ABCF1-3 and ABCG1-8 subfamily. Although the originally funtion of transporter is to transport specific physiological substrate such as nutrient, hormone, cytokines, neurotransmitters and other physiological subtances across cell membrane the specificity is not restricted to each substrate. Drugs and other xenobiotics which have structural similarity to the physiological substrates are recognized and transported by the related transporters. The competition of them on transporters therefore may lead to the occurence of drug-drug interactions (DDI or drugphysiological substrate interaction in the drug-kinetics phase. Many transporters located in the liver, intestinal and renal epithelial cell membranes involve in the transport of endogenous substance or xenobiotics including drugs play important roles as protective barrier. Since transporters also serve as the targets of drug action it is understood that transporters play important role in the pathogenesis of diseases as well as in the drug therapy of diseases.

  2. 77 FR 38747 - Reports by Air Carriers on Incidents Involving Animals During Air Transport

    Science.gov (United States)

    2012-06-29

    ...-2010-0211] RIN 2105-AE07 Reports by Air Carriers on Incidents Involving Animals During Air Transport... incidents involving animals during air transport, 14 CFR 234.13, to expand the reporting requirement to U.S... seats, to expand the definition of ``animal'' to include all cats and dogs transported by the carrier...

  3. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Science.gov (United States)

    2010-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to or...

  4. Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Svenningsen, Katrine; Knudsen, Lina Almind

    2015-01-01

    transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein (P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2 (MRP2) and ABCG2/breast cancer resistance protein (BCRP), Abcb1...... with glucocorticoids. The evidence for the involvement of ABCC2 and ABCG2 in colonic pathophysiology was weak. CONCLUSION: ABCB1, diet, and gut microbes mutually interact in colonic inflammation, a well-known risk factor for CRC. Further insight may be translated into preventive and treatment strategies....... pathogen-free Abcb1 KO mice. The Abcb1 KO mice might thus serve as a model in which diet/environmental factors and microbes may be controlled and investigated in relation to intestinal inflammation. Potential molecular mechanisms include defective transport of inflammatory mediators and/or phospholipid...

  5. Transportation accidents/incidents involving radioactive materials (1971-1991)

    International Nuclear Information System (INIS)

    Cashwell, C.E.; McClure, J.D.

    1993-01-01

    In 1981, Sandia National Laboratories developed the Radioactive Materials Incident Report (RMIR) database to support its research and development activities for the U.S. Department of Energy (DOE). The RMIR database contains information on transportation accidents/incidents with radioactive materials that have occurred since 1971. The RMIR classifies a transportation accident/incident in one of six ways: as a transportation accident, a handling accident, a reported incident, missing or stolen, cask weeping, or other. This paper will define these terms and provide detailed examples of each. (J.P.N.)

  6. Uptake of L-cystine via an ABC transporter contributes defense of oxidative stress in the L-cystine export-dependent manner in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Iwao Ohtsu

    Full Text Available Intracellular thiols like L-cystine and L-cystine play a critical role in the regulation of cellular processes. Here we show that Escherichia coli has two L-cystine transporters, the symporter YdjN and the ATP-binding cassette importer FliY-YecSC. These proteins import L-cystine, an oxidized product of L-cystine from the periplasm to the cytoplasm. The symporter YdjN, which is expected to be a new member of the L-cystine regulon, is a low affinity L-cystine transporter (Km = 1.1 μM that is mainly involved in L-cystine uptake from outside as a nutrient. E. coli has only two L-cystine importers because ΔydjNΔyecS mutant cells are not capable of growing in the minimal medium containing L-cystine as a sole sulfur source. Another protein YecSC is the FliY-dependent L-cystine transporter that functions cooperatively with the L-cystine transporter YdeD, which exports L-cystine as reducing equivalents from the cytoplasm to the periplasm, to prevent E. coli cells from oxidative stress. The exported L-cystine can reduce the periplasmic hydrogen peroxide to water, and then generated L-cystine is imported back into the cytoplasm via the ATP-binding cassette transporter YecSC with a high affinity to L-cystine (Km = 110 nM in a manner dependent on FliY, the periplasmic L-cystine-binding protein. The double disruption of ydeD and fliY increased cellular levels of lipid peroxides. From these findings, we propose that the hydrogen peroxide-inducible L-cystine/L-cystine shuttle system plays a role of detoxification of hydrogen peroxide before lipid peroxidation occurs, and then might specific prevent damage to membrane lipids.

  7. Split tasks of asymmetric nucleotide-binding sites in the heterodimeric ABC exporter EfrCD.

    Science.gov (United States)

    Hürlimann, Lea M; Hohl, Michael; Seeger, Markus A

    2017-06-01

    Many heterodimeric ATP-binding cassette (ABC) exporters evolved asymmetric ATP-binding sites containing a degenerate site incapable of ATP hydrolysis due to noncanonical substitutions in conserved sequence motifs. Recent studies revealed that nucleotide binding to the degenerate site stabilizes contacts between the nucleotide-binding domains (NBDs) of the inward-facing transporter and regulates ATP hydrolysis at the consensus site via allosteric coupling mediated by the D-loops. However, it is unclear whether nucleotide binding to the degenerate site is strictly required for substrate transport. In this study, we examined the functional consequences of a systematic set of mutations introduced at the degenerate and consensus site of the multidrug efflux pump EfrCD of Enterococcus faecalis. Mutating motifs which differ among the two ATP-binding sites (Walker B, switch loop, and ABC signature) or which are involved in interdomain communication (D-loop and Q-loop) led to asymmetric results in the functional assays and were better tolerated at the degenerate site. This highlights the importance of the degenerate site to allosterically regulate the events at the consensus site. Mutating invariant motifs involved in ATP binding and NBD closure (A-loop and Walker A) resulted in equally reduced transport activities, regardless at which ATP-binding site they were introduced. In contrast to previously investigated heterodimeric ABC exporters, mutation of the degenerate site Walker A lysine completely inactivated ATPase activity and substrate transport, indicating that ATP binding to the degenerate site is essential for EfrCD. This study provides novel insights into the split tasks of asymmetric ATP-binding sites of heterodimeric ABC exporters. © 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  8. The yeast ABC transporter Pdr18 (ORF YNR070w) controls plasma membrane sterol composition, playing a role in multidrug resistance

    Science.gov (United States)

    Cabrito, Tânia R.; Teixeira, Miguel C.; Singh, Ashutosh; Prasad, Rajendra; Sá-Correia, Isabel

    2011-01-01

    The action of multidrug efflux pumps in MDR (multidrug resistance) acquisition has been proposed to partially depend on the transport of physiological substrates which may indirectly affect drug partition and transport across cell membranes. In the present study, the PDR18 gene [ORF (open reading frame) YNR070w], encoding a putative PDR (pleiotropic drug resistance) transporter of the ATP-binding cassette superfamily, was found to mediate plasma membrane sterol incorporation in yeast. The physiological role of Pdr18 is demonstrated to affect plasma membrane potential and is proposed to underlie its action as a MDR determinant, conferring resistance to the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid). The action of Pdr18 in yeast tolerance to 2,4-D, which was found to contribute to reduce [14C]2,4-D intracellular accumulation, may be indirect, given the observation that 2,4-D exposure deeply affects the sterol plasma membrane composition, this effect being much stronger in a Δpdr18 background. PDR18 activation under 2,4-D stress is regulated by the transcription factors Nrg1, controlling carbon source availability and the stress response, and, less significantly, Yap1, involved in oxidative stress and MDR, and Pdr3, a key regulator of the yeast PDR network, consistent with a broad role in stress defence. Taken together, the results of the present study suggest that Pdr18 plays a role in plasma membrane sterol incorporation, this physiological trait contributing to an MDR phenotype. PMID:21831043

  9. Suppression of c-Myc is involved in multi-walled carbon nanotubes' down-regulation of ATP-binding cassette transporters in human colon adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaojing [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Xu, Yonghong [Institute of Ophthalmological Research, Department of Ophthalmology, Renmin Hospital of Wuhan University, 430060 Wuhan (China); Meng, Xiangning [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Watari, Fumio [Department of Biomedical, Dental Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Sapporo 060-8586 (Japan); Liu, Hudan, E-mail: hudanliu@hust.edu.cn [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Chen, Xiao, E-mail: mornsmile@yahoo.com [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China)

    2015-01-01

    Over-expression of ATP-binding cassette (ABC) transporters, a large family of integral membrane proteins that decrease cellular drug uptake and accumulation by active extrusion, is one of the major causes of cancer multi-drug resistance (MDR) that frequently leads to failure of chemotherapy. Carbon nanotubes (CNTs)-based drug delivery devices hold great promise in enhancing the efficacy of cancer chemotherapy. However, CNTs' effects on the ABC transporters remain under-investigated. In this study, we found that multiwalled carbon nanotubes (MWCNTs) reduced transport activity and expression of ABC transporters including ABCB1/Pgp and ABCC4/MRP4 in human colon adenocarcinoma Caco-2 cells. Proto-oncogene c-Myc, which directly regulates ABC gene expression, was concurrently decreased in MWCNT-treated cells and forced over-expression of c-Myc reversed MWCNTs' inhibitory effects on ABCB1 and ABCC4 expression. MWCNT-cell membrane interaction and cell membrane oxidative damage were observed. However, antioxidants such as vitamin C, β-mecaptoethanol and dimethylthiourea failed to antagonize MWCNTs' down-regulation of ABC transporters. These data suggest that MWCNTs may act on c-Myc, but not through oxidative stress, to down-regulate ABC transporter expression. Our findings thus shed light on CNTs' novel cellular effects that may be utilized to develop CNTs-based drug delivery devices to overcome ABC transporter-mediated cancer chemoresistance.

  10. Maintenance Policy in Public-Transport Involving Government Subsidy

    Science.gov (United States)

    Pasaribu, U. S.; Bayuzetra, Y.; Gunawan, L. E.; Husniah, H.

    2018-02-01

    A public transport with government subsidy is considered to encourage the sustainability of the transportation. The transportations revenue is determined by the maximum of the uptimes of the vehicle. In this paper, we study a one-dimensional maintenance policy for new vehicle which is characterized by age parameter. We consider that the degradation of the vehicle is affected by the age of the vehicle, and modelled by using a one-dimensional approach. The owner performs both preventive and corrective maintenance actions, and the preventive maintenance action will reduce the vehicle failure rate and hence it will decrease the corrective maintenance cost during the life time of the vehicle. The decision problem for the owner is to find the optimal preventive maintenance time of the vehicle of each subsidy option offered by maximizing the expected profit for each subsidy.

  11. ABC's of Being Smart

    Science.gov (United States)

    Foster, Joanne

    2011-01-01

    Determining what giftedness is all about means focusing on many aspects of the individual. In this paper, the author focuses on letter D of the ABC's of being smart. She starts with specifics about giftedness (details), and then moves on to some ways of thinking (dispositions).

  12. Diffusive transport in a one dimensional disordered potential involving correlations

    International Nuclear Information System (INIS)

    Monthus, C.; Paris-6 Univ., 75

    1995-03-01

    Transport properties of one dimensional Brownian diffusion under the influence of a quenched random force, distributed as a two-level Poisson process is discussed. Large time scaling laws of the position of the Brownian particle, and the probability distribution of the stationary flux going through a sample between two prescribed concentrations are studied. (author) 14 refs.; 3 figs

  13. Inventory and analysis of ATP-binding cassette (ABC) systems in Brugia malayi.

    Science.gov (United States)

    Ardelli, B F; Stitt, L E; Tompkins, J B

    2010-07-01

    ABC systems are one of the largest described protein superfamilies. These systems have a domain organization that may contain 1 or more transmembrane domains (ABC_TM1F) and 1 or 2 ATP-binding domains (ABC_2). The functions (e.g., import, export and DNA repair) of these proteins distinguish the 3 classes of ABC systems. Mining and PCR-based cloning were used to identify 33 putative ABC systems from the Brugia malayi genome. There were 31 class 2 genes, commonly called ABC transporters, and 2 class 3 genes. The ABC transporters were divided into subfamilies. Three belonged to subfamily A, 16 to subfamily B, 5 to subfamily C, 1 to subfamily E and 3 to subfamilies F and G, respectively. None were placed in subfamilies D and H. Similar to other ABC systems, the ABC_2 domain of B. malayi genes was conserved and contained the Walker A and B motifs, the signature sequence/linker region and the switch region with the conserved histidine. The ABC_TM1F domain was less conserved. The relative abundance of ABC systems was quantified using real-time reverse transcription PCR and was significantly higher in female adults of B. malayi than in males and microfilaria, particularly those in subfamilies B and C, which are associated with drug resistance.

  14. [Research progress in chondroitinase ABC].

    Science.gov (United States)

    Li, Ye; Chen, Zhenya; Yuan, Qipeng

    2015-05-01

    As the components of proteoglycans, glycosaminoglycans (GAGs) are linear polysaccharides consisting of hexose and uronic acid units linked by β-1,3-glycosidic bond. GAGs mainly distribute in extracellular matrix and on cell surfaces. They guide many biological processes, such as proliferation of cells, transmission of signals and mediation of inflammation. Because of their large molecular weights, GAGs have limited biological functions in vitro. However, the appearance of chondroitinase ABC (ChSase ABC), which can lyse polysaccharides, solves the difficulties. Based on our work, we summarized the classification and the crystal structure of ChSase ABC, as well as other recent research progress on ChSase ABCs. The separation and purification methods of ChSase ABC and construction of engineering bacteria are illustrated. The stability and immobilization are also analyzed by taking account of the characterization of ChSase ABC. Finally, problems and future prospect of the ChSase ABC study are summarized.

  15. General mechanism for helium blistering involving displaced atom transport

    Energy Technology Data Exchange (ETDEWEB)

    McDonell, W.R.

    1979-01-01

    A mechanism developed to account for formation of vertically elongated blisters in high displacement environments produced by /sup 252/Cf alpha particles and fission fragments has been extended to formation of done-shaped blisters in the low displacement environments produced by simple helium ion beams. In this mechanism, transport of displaced atoms to relieve compressive stresses in the helium-implanted layer allows interconnections of small, subsurface bubbles to form the blister cavity. The same transport may cause thickening of the blister caps at low implantation energies. The transition from dome-shaped to vertically elongated blistering occurs between the 300 and 3000 displacements per helium atom produced by simple helium ions and /sup 252/Cf radiations respectively.

  16. Field Efficiency of Slurry Applications Involving In-field Transports

    DEFF Research Database (Denmark)

    Bochtis, Dionysis; Sørensen, Claus Aage Grøn; Green, Ole

    2009-01-01

    Controlled traffic farming can significantly reduce the soil compaction caused from heavy machinery systems. However, using CTF in material handling operations executed by cooperative machines, the significantly increased in-field transports lead to a lower system’s efficiency. Recently, a discrete...... traffic system and the corresponding operation under the CTF system are presented and analyzed. . Key word:  Controlled traffic, cooperative machines, machinery management...

  17. Polymorphism in a second ABC transproter gene located within the class II region of the human major histocompatibility complex

    Energy Technology Data Exchange (ETDEWEB)

    Powis, S.H.; Mockridge, I.; Kelly, A.; Glynne, R.; Beck, S.; Trowsdale, J. (Imperial Cancer Research Fund Labs., London (United Kingdom)); Kerr, L.A. (Guy' s Campus, London (United Kingdom)); Gileadi, U. (Univ. of Oxford (United Kingdom))

    1992-02-15

    Recent studies have identified genes within the major histocompatibility complex (MHC) that may play a role in presentation of antigenic peptides to T cells. The authors have previously described RING4, a gene within the human MHC class II region that has sequence homology with members of the ABC (ATP-binding cassette) transporter superfamily. They now report the nucleotide sequence of RING11, a second ABC transporter gene located approximately 7 kilobases telomeric to RING4. RING11 is {gamma}-interferon inducible, a property shared with other genes involved in antigen presentation. Comparison between the amino acid sequences of RING11 and RING4 reveals strong homology. They propose that they form a heterodimer that transports peptides from the cytoplasm into the endoplasmic reticulum. They have identified two RING11 alleles, which differ in length of their derived protein sequence by 17 amino acids. The more common of these alleles is present in a Caucasoid population at a frequency of 79%.

  18. 31 CFR 585.207 - Prohibited transportation-related transactions involving the FRY (S&M).

    Science.gov (United States)

    2010-07-01

    ... transactions involving the FRY (S&M). 585.207 Section 585.207 Money and Finance: Treasury Regulations Relating... transactions involving the FRY (S&M). Except as otherwise authorized, the following are prohibited: (a) Any... transportation to or from the FRY (S&M); (b) The provision of transportation to or from the United States by: (1...

  19. ATP-binding cassette transporters in reproduction: a new frontier

    Science.gov (United States)

    Bloise, E.; Ortiga-Carvalho, T.M.; Reis, F.M.; Lye, S.J.; Gibb, W.; Matthews, S.G.

    2016-01-01

    BACKGROUND The transmembrane ATP-binding cassette (ABC) transporters actively efflux an array of clinically relevant compounds across biological barriers, and modulate biodistribution of many physiological and pharmacological factors. To date, over 48 ABC transporters have been identified and shown to be directly and indirectly involved in peri-implantation events and fetal/placental development. They efflux cholesterol, steroid hormones, vitamins, cytokines, chemokines, prostaglandins, diverse xenobiotics and environmental toxins, playing a critical role in regulating drug disposition, immunological responses and lipid trafficking, as well as preventing fetal accumulation of drugs and environmental toxins. METHODS This review examines ABC transporters as important mediators of placental barrier functions and key reproductive processes. Expression, localization and function of all identified ABC transporters were systematically reviewed using PubMed and Google Scholar websites to identify relevant studies examining ABC transporters in reproductive tissues in physiological and pathophysiological states. Only reports written in English were incorporated with no restriction on year of publication. While a major focus has been placed on the human, extensive evidence from animal studies is utilized to describe current understanding of the regulation and function of ABC transporters relevant to human reproduction. RESULTS ABC transporters are modulators of steroidogenesis, fertilization, implantation, nutrient transport and immunological responses, and function as ‘gatekeepers’ at various barrier sites (i.e. blood-testes barrier and placenta) against potentially harmful xenobiotic factors, including drugs and environmental toxins. These roles appear to be species dependent and change as a function of gestation and development. The best-described ABC transporters in reproductive tissues (primarily in the placenta) are the multidrug transporters p-glycoprotein and

  20. ABC+SCM=Sant?

    OpenAIRE

    Dahl, Jonas; Porelius, Jesper

    2006-01-01

    Background: Companies of today commonly search to gain competitive advantages throughout different forms of co-operation, one of which is referred to as Supply Chain Management. Although little research has been assigned to the topic of how to manage and control this type of relation, lately a growing number of academics has been arguing that ABC is an appropriate mean of controlling this type of relationships. Purpose: The purpose of this thesis is to investigate to what degree the ongoing d...

  1. Evaluation of the role of ATP-binding cassette transporters as a defence mechanism against temephos in populations of Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Estelita Pereira Lima

    2014-11-01

    Full Text Available The role of ATP-binding cassette (ABC transporters in the efflux of the insecticide, temephos, was assessed in the larvae of Aedes aegypti. Bioassays were conducted using mosquito populations that were either susceptible or resistant to temephos by exposure to insecticide alone or in combination with sublethal doses of the ABC transporter inhibitor, verapamil (30, 35 and 40 μM. The best result in the series was obtained with the addition of verapamil (40 μM, which led to a 2x increase in the toxicity of temephos, suggesting that ABC transporters may be partially involved in conferring resistance to the populations evaluated.

  2. Flavonoid-mediated inhibition of intestinal ABC transporters may affect the oral bioavailability of drugs, food-borne toxic compounds and bioactive ingredients

    NARCIS (Netherlands)

    Brand, W.; Schutte, M.E.; Williamson, G.; Zanden, J.J. van; Cnubben, N.H.P.; Groten, J.P.; Bladeren, P.J. van; Rietjens, I.M.C.M.

    2006-01-01

    The transcellular transport of ingested food ingredients across the intestinal epithelial barrier is an important factor determining bioavailability upon oral intake. This transcellular transport of many chemicals, food ingredients, drugs or toxic compounds over the intestinal epithelium can be

  3. Thermodynamics of the ATPase cycle of GlcV, the nucleotide-binding domain of the glucose ABC transporter of Sulfolobus solfataricus

    NARCIS (Netherlands)

    Pretz, Monika G.; Albers, Sonja-Verena; Schuurman-Wolters, Gea; Tampe, Robert; Driessen, Arnold J. M.; van der Does, Chris

    2006-01-01

    ATP-binding cassette transporters drive the transport of substrates across the membrane by the hydrolysis of ATP. They typically have a conserved domain structure with two membrane-spanning domains that form the transport channel and two cytosolic nucleotide-binding domains ( NBDs) that energize the

  4. ATP-binding cassette-like transporters are involved in the transport of lignin precursors across plasma and vacuolar membranes

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Y.C.; Liu, C.

    2010-12-28

    Lignin is a complex biopolymer derived primarily from the condensation of three monomeric precursors, the monolignols. The synthesis of monolignols occurs in the cytoplasm. To reach the cell wall where they are oxidized and polymerized, they must be transported across the cell membrane. However, the molecular mechanisms underlying the transport process are unclear. There are conflicting views about whether the transport of these precursors occurs by passive diffusion or is an energized active process; further, we know little about what chemical forms are required. Using isolated plasma and vacuolar membrane vesicles prepared from Arabidopsis, together with applying different transporter inhibitors in the assays, we examined the uptake of monolignols and their derivatives by these native membrane vesicles. We demonstrate that the transport of lignin precursors across plasmalemma and their sequestration into vacuoles are ATP-dependent primary-transport processes, involving ATP-binding cassette-like transporters. Moreover, we show that both plasma and vacuolar membrane vesicles selectively transport different forms of lignin precursors. In the presence of ATP, the inverted plasma membrane vesicles preferentially take up monolignol aglycones, whereas the vacuolar vesicles are more specific for glucoconjugates, suggesting that the different ATP-binding cassette-like transporters recognize different chemical forms in conveying them to distinct sites, and that glucosylation of monolignols is necessary for their vacuolar storage but not required for direct transport into the cell wall in Arabidopsis.

  5. Diversity and evolution of ABC proteins in mycorrhiza-forming fungi

    OpenAIRE

    Kovalchuk, Andriy; Kohler, Annegret; Martin, Francis; Asiegbu, Fred O

    2015-01-01

    Abstract Background Transporter proteins are predicted to have an important role in the mycorrhizal symbiosis, due to the fact that this type of an interaction between plants and fungi requires a continuous nutrient and signalling exchange. ABC transporters are one of the large groups of transporter proteins found both in plants and in fungi. The crucial role of plant ABC transporters in the formation of the mycorrhizal symbiosis has bee...

  6. Curva ABC de fornecedores

    OpenAIRE

    Solano, Renato da Silva

    2003-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. Este trabalho faz uma revisão e busca dar uma contribuição aos gerentes de Planejamento, Programação, Controle e Gerenciamento de Empreendimentos e Obras através do uso das Curvas ABC. O trabalho utilizou 10 empreendimentos de classificação Alta (NBR 12721), incorporados por oito empresas do setor e fez uma análise dos projetos-padrão da NBR 12721. Foi f...

  7. Do You Know Your ABC?

    Science.gov (United States)

    Neale, Claire

    2013-01-01

    Within primary schools, the core subjects of literacy and numeracy are highly regarded, and rightly so, as children need to learn to read, write and be numerically literate. This means that all children learn their ABCs at an early age, But, what about the "other ABC"--"Airway, Breathing and Circulation?" Accidents and medical…

  8. Planning and Preparing for Emergency Response to Transport Accidents Involving Radioactive Material. Safety Guide

    International Nuclear Information System (INIS)

    2009-01-01

    This Safety Guide provides guidance on various aspects of emergency planning and preparedness for dealing effectively and safely with transport accidents involving radioactive material, including the assignment of responsibilities. It reflects the requirements specified in Safety Standards Series No. TS-R-1, Regulations for the Safe Transport of Radioactive Material, and those of Safety Series No. 115, International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources. Contents: 1. Introduction; 2. Framework for planning and preparing for response to accidents in the transport of radioactive material; 3. Responsibilities for planning and preparing for response to accidents in the transport of radioactive material; 4. Planning for response to accidents in the transport of radioactive material; 5. Preparing for response to accidents in the transport of radioactive material; Appendix I: Features of the transport regulations influencing emergency response to transport accidents; Appendix II: Preliminary emergency response reference matrix; Appendix III: Guide to suitable instrumentation; Appendix IV: Overview of emergency management for a transport accident involving radioactive material; Appendix V: Examples of response to transport accidents; Appendix VI: Example equipment kit for a radiation protection team; Annex I: Example of guidance on emergency response to carriers; Annex II: Emergency response guide.

  9. Understanding Municipal Officials' Involvement in Transportation Policies Supportive of Walking and Bicycling.

    Science.gov (United States)

    Zwald, Marissa L; Eyler, Amy A; Goins, Karin Valentine; Brownson, Ross C; Schmid, Thomas L; Lemon, Stephenie C

    Local transportation policies can impact the built environment and physical activity. Municipal officials play a critical role in transportation policy and planning decisions, yet little is known about what influences their involvement. To describe municipal officials' involvement in transportation policies that were supportive of walking and bicycling and to examine individual- and job-related predictors of involvement in transportation policies among municipal officials. A cross-sectional survey was administered online from June to July 2012 to municipal officials in 83 urban areas with a population of 50 000 or more residents across 8 states. A total of 461 municipal officials from public health, planning, transportation, public works, community and economic development, parks and recreation, city management, and municipal legislatures responded to the survey. Participation in the development, adoption, or implementation of a municipal transportation policy supportive of walking or bicycling. Multivariate logistic regression analyses, conducted in September 2013, revealed that perceived importance of economic development and traffic congestion was positively associated with involvement in a municipal transportation policy (odds ratio [OR] = 1.32, 95% confidence interval [CI] = 1.02-1.70; OR = 1.59, 95% CI = 1.26-2.01, respectively). Higher perceived resident support of local government to address economic development was associated with an increased likelihood of participation in a transportation policy (OR = 1.70, 95% CI = 1.24-2.32). Respondents who perceived lack of collaboration as a barrier were less likely to be involved in a transportation policy (OR = 0.78, 95% CI = 0.63-0.97). Municipal officials who lived in the city or town in which they worked were significantly more likely to be involved in a transportation policy (OR = 1.83, 95% CI = 1.05-3.17). Involvement in a local transportation policy by a municipal official was associated with greater

  10. Genome organisation and expression profiling of ABC protein-encoding genes in Heterobasidion annosum s.l. complex.

    Science.gov (United States)

    Baral, Bikash; Kovalchuk, Andriy; Asiegbu, Fred O

    2016-03-01

    Members of Heterobasidion annosum species complex are widely regarded as the most destructive fungal pathogens of conifer trees in the boreal and temperate zones of Northern hemisphere. To invade and colonise their host trees, Heterobasidion fungi must overcome components of host chemical defence, including terpenoid oleoresin and phenolic compounds. ABC transporters may play an important role in this process participating in the export of toxic host metabolites and maintaining their intracellular concentration below the critical level. We have identified and phylogenetically classified Heterobasidion genes encoding ABC transporters and closely related ABC proteins. The number of ABC proteins in the Heterobasidion genome is one of the lowest among analysed species of Agaricomycotina. Using quantitative RT-PCR, we have analysed transcriptional response of Heterobasidion ABC transporter-encoding genes to monoterpenes as well as their expression profile during growth on pine wood in comparison to the growth on defined media. Several ABC transporters were up-regulated during growth on pine wood. The ABC-transporter encoding gene ABCG1.1 was induced both during growth of H. annosum on pine wood and upon exposure to monoterpenes. Our experimental data demonstrate the differential responses of Heterobasidion ABC genes to growth conditions and chemical stressors. The presented results suggest a potential role of Heterobasidion ABC-G transporters in the resistance to the components of conifer chemical defence. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  11. The chemistry of ABC

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, R.J. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    ABC stand for accelerator based conversion of Pu. It is a unique approach to Pu destruction that allows for a well controlled and complete burn of Pu as may be required by treaty or policy. The central idea of the approach is to provide a spallation source of neutrons that allows the operation of a fissioning system without a critical mass and at a K effective less than one. Material to be fissioned is suspended in a molten salt medium for high temperature control and on-line removal of neutron absorbing fission products. This paper discusses the issues associated with the selection and operation of a molten salt chemical system: redox control, product removal, material feed, solubilities, deposition control, and a host of operational procedures.

  12. The domain II loops of Bacillus thuringiensis Cry1Aa form an overlapping interaction site for two Bombyx mori larvae functional receptors, ABC transporter C2 and cadherin-like receptor.

    Science.gov (United States)

    Adegawa, Satomi; Nakama, Yui; Endo, Haruka; Shinkawa, Naoki; Kikuta, Shingo; Sato, Ryoichi

    2017-02-01

    Information about the receptor-interaction region of Cry toxins, insecticidal proteins produced by Bacillus thuringiensis, is needed to elucidate the mode of action of Cry toxins and improve their toxicity through protein engineering. We analyzed the interaction sites on Cry1Aa with ABC transporter C2 (ABCC2), one of the most important Cry1A toxin receptors. A competitive binding assay revealed that the Bombyx mori ABCC2 (BmABCC2) Cry1A binding site was the same as the BtR175 binding site, suggesting that the loop region of Cry1Aa domain II is a binding site. Next, we constructed several domain II loop mutant toxins and tested their binding affinity in an SPR analysis, and also performed a cell swelling assay to evaluate receptor-mediated cytotoxicity. Our results indicate that the loop regions required for BtR175 and BmABCC2 binding and the regions important for cytotoxicity partially overlap. Our results also suggest that receptor binding is necessary but not sufficient for cytotoxicity. This is the first report showing the region of interaction between ABCC2 and Cry1Aa and the cytotoxicity-relevant properties of the Cry1Aa domain II loop region. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Purification, crystallization and preliminary X-ray analysis of the galacto-N-biose-/lacto-N-biose I-binding protein (GL-BP) of the ABC transporter from Bifidobacterium longum JCM1217

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Jun [Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Suzuki, Ryuichiro; Fushinobu, Shinya [Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Kitaoka, Motomitsu [National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642 (Japan); Wakagi, Takayoshi; Shoun, Hirofumi [Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Ashida, Hisashi [Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Kumagai, Hidehiko; Katayama, Takane, E-mail: takane@ishikawa-pu.ac.jp [Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836 (Japan); Yamamoto, Kenji [Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

    2007-09-01

    Preliminary X-ray analysis of the galacto-N-biose-/lacto-N-biose I-binding protein (GL-BP) of the ABC transporter from B. longum is described. A recombinant galacto-N-biose-/lacto-N-biose I-binding protein (GL-BP) from Bifidobacterium longum JCM1217 has been prepared and crystallized by the hanging-drop vapour-diffusion method using 10 mg ml{sup −1} purified enzyme, 0.01 M zinc sulfate, 0.1 M MES buffer pH 5.9–6.4 and 20–22%(v/v) PEG MME 550 in the presence of 5 mM disaccharide ligands. Suitable crystals grew after 10 d incubation at 293 K. The crystals belong to space group C222{sub 1}, with unit-cell parameters a = 106.3, b = 143.6, c = 114.6 Å for the lacto-N-biose I complex and a = 106.4, b = 143.4, c = 115.5 Å for the galacto-N-biose complex, and diffracted to 1.85 and 1.99 Å resolution, respectively.

  14. The Arabidopsis thaliana ABC protein superfamily, a complete inventory.

    Science.gov (United States)

    Sánchez-Fernández, R; Davies, T G; Coleman, J O; Rea, P A

    2001-08-10

    We describe the first complete inventory of ATP-binding cassette (ABC) proteins from a multicellular organism, the model plant Arabidopsis thaliana. By the application of several search criteria, Arabidopsis was found to contain a total of 129 open reading frames (ORFs) capable of encoding ABC proteins, of which 103 possessed contiguous transmembrane spans and were identified as putative intrinsic membrane proteins. Fifty-two of the putative intrinsic membrane proteins contained at least two transmembrane domains (TMDs) and two nucleotide-binding folds (NBFs) and could be classified as belonging to one of five subfamilies of full-molecule transporters. The other 51 putative membrane proteins, all of which were half-molecule transporters, fell into five subfamilies. Of the remaining ORFs identified, all of which encoded proteins lacking TMDs, 11 could be classified into three subfamilies. There were no obvious homologs in other organisms for 15 of the ORFs which encoded a heterogeneous group of non-intrinsic ABC proteins (NAPs). Unrooted phylogenetic analyses substantiated the subfamily designations. Notable features of the Arabidopsis ABC superfamily was the presence of a large yeast-like PDR subfamily, and the absence of genes encoding bona fide cystic fibrosis transmembrane conductance regulator (CFTR), sulfonylurea receptor (SUR), and heavy metal tolerance factor 1 (HMT1) homologs. Arabidopsis was unusual in its large allocation of ORFs (a minimum of 0.5%) to members of the ABC protein superfamily.

  15. The ABCs of Sex Ed.

    Science.gov (United States)

    Sroka, Stephen R.

    2002-01-01

    Cites statistics on extent of sexually transmitted diseases and pregnancies among adolescents; describes ideological dispute over how to teach sex education; advocates teaching the ABCs of sex education: Abstinence, Be Monogamous, and Condoms. (PKP)

  16. Politseiniku lustlik ABC / Pekka Erelt

    Index Scriptorium Estoniae

    Erelt, Pekka, 1965-

    1999-01-01

    Politsei on välja andnud 'Politseiniku ABC', mis antakse igale politseinikule. Karikaturist Heiki Ernits on peaaegu igale taskuraamatu leheküljele joonistanud pildikese mundrimeestest kentsakates situatsioonides.

  17. The Yeast ATP-binding Cassette (ABC) Transporter Ycf1p Enhances the Recruitment of the Soluble SNARE Vam7p to Vacuoles for Efficient Membrane Fusion*

    Science.gov (United States)

    Sasser, Terry L.; Lawrence, Gus; Karunakaran, Surya; Brown, Christopher; Fratti, Rutilio A.

    2013-01-01

    The Saccharomyces cerevisiae vacuole contains five ATP-binding cassette class C (ABCC) transporters, including Ycf1p, a family member that was originally characterized as a Cd2+ transporter. Ycf1p has also been found to physically interact with a wide array of proteins, including factors that regulate vacuole homeostasis. In this study, we examined the role of Ycf1p and other ABCC transporters in the regulation of vacuole homotypic fusion. We found that deletion of YCF1 attenuated in vitro vacuole fusion by up to 40% relative to wild-type vacuoles. Plasmid-expressed wild-type Ycf1p rescued the deletion phenotype; however, Ycf1p containing a mutation of the conserved Lys-669 to Met in the Walker A box of the first nucleotide-binding domain (Ycf1pK669M) was unable to complement the fusion defect of ycf1Δ vacuoles. This indicates that the ATPase activity of Ycf1p is required for its function in regulating fusion. In addition, we found that deleting YCF1 caused a striking decrease in vacuolar levels of the soluble SNARE Vam7p, whereas total cellular levels were not altered. The attenuated fusion of ycf1Δ vacuoles was rescued by the addition of recombinant Vam7p to in vitro experiments. Thus, Ycf1p contributes in the recruitment of Vam7p to the vacuole for efficient membrane fusion. PMID:23658021

  18. Accelerated bridge construction (ABC) decision making and economic modeling tool.

    Science.gov (United States)

    2011-12-01

    In this FHWA-sponsored pool funded study, a set of decision making tools, based on the Analytic Hierarchy Process (AHP) was developed. This tool set is prepared for transportation specialists and decision-makers to determine if ABC is more effective ...

  19. Genome-Wide Identification and Expression Profiling of ATP-Binding Cassette (ABC Transporter Gene Family in Pineapple (Ananas comosus (L. Merr. Reveal the Role of AcABCG38 in Pollen Development

    Directory of Open Access Journals (Sweden)

    Piaojuan Chen

    2017-12-01

    Full Text Available Pineapple (Ananas comosus L. cultivation commonly relies on asexual reproduction which is easily impeded by many factors in agriculture production. Sexual reproduction might be a novel approach to improve the pineapple planting. However, genes controlling pineapple sexual reproduction are still remain elusive. In different organisms a conserved superfamily proteins known as ATP binding cassette (ABC participate in various biological processes. Whereas, till today the ABC gene family has not been identified in pineapple. Here 100 ABC genes were identified in the pineapple genome and grouped into eight subfamilies (5 ABCAs, 20 ABCBs, 16 ABCCs, 2 ABCDs, one ABCEs, 5 ABCFs, 42 ABCGs and 9 ABCIs. Gene expression profiling revealed the dynamic expression pattern of ABC gene family in various tissues and different developmental stages. AcABCA5, AcABCB6, AcABCC4, AcABCC7, AcABCC9, AcABCG26, AcABCG38 and AcABCG42 exhibited preferential expression in ovule and stamen. Over-expression of AcABCG38 in the Arabidopsis double mutant abcg1-2abcg16-2 partially restored its pollen abortion defects, indicating that AcABCG38 plays important roles in pollen development. Our study on ABC gene family in pineapple provides useful information for developing sexual pineapple plantation which could be utilized to improve pineapple agricultural production.

  20. Experience in the analysis of accidents and incidents involving the transport of radioactive materials

    International Nuclear Information System (INIS)

    Warner-Jones, S.M.; Hughes, J.S.; Shaw, K.B.

    2002-01-01

    Some half a million packages containing radioactive materials are transported to, from and within the UK annually. Accidents and incidents involving these shipments are rare. However, there is always the potential for such an event, which could lead to a release of the contents of a package or an increase in radiation level caused by damaged shielding. These events could result in radiological consequences for transport workers. As transport occurs in the public environment, such events could also lead to radiation exposures of members of the public. The UK Department for Transport (DfT), together with the Health and Safety Executive (HSE) have supported, for almost 20 years, work to compile, analyse and report on accidents and incidents that occur during the transport of radioactive materials. Annual reports on these events have been produced for twelve years. The details of these events are recorded in the Radioactive Materials Transport Event Database (RAMTED) maintained by the National Radiological Protection Board on behalf of the DfT and HSE. Information on accidents and incidents dates back to 1958. RAMTED currently includes information of 708 accidents and incidents, covering the period 1958 to 2000. This paper presents a summary of the data covering this period, identifying trends and lessons learned together with a discussion of some examples. It was found that, historically, the most significant exposures were received as a result of accidents involving the transport of industrial radiography sources. However, the frequency and severity of these events has decreased considerably in the later years of this study due to improvements in training, awareness and equipment. The International Atomic Energy Agency and the Nuclear Energy Agency, have established the international nuclear event scale (INES), which is described in detail in a users' guide. The INES has been revised to fully include transport events, and the information in RAMTED has been reviewed

  1. Identification of five partial ABC genes in the liver of the Antarctic fish Trematomus bernacchii and sensitivity of ABCB1 and ABCC2 to Cd exposure

    Energy Technology Data Exchange (ETDEWEB)

    Zucchi, Sara, E-mail: zucchi2@unisi.i [Department of Environmental Sciences ' G. Sarfatti' , University of Siena, Via Mattioli 4, 53100 Siena (Italy); Corsi, Ilaria [Department of Environmental Sciences ' G. Sarfatti' , University of Siena, Via Mattioli 4, 53100 Siena (Italy); Luckenbach, Till [UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, D-04318 Leipzig (Germany); Bard, Shannon Mala [Environmental Programmes, Dalhousie University, 1355 Oxford Street, Life Science Centre, Room 820, Halifax, Nova Scotia, Canada B3H 4J1 (Canada); Regoli, Francesco [Department of Biochemistry, Biology and Genetics, Polytechnic University of Marches, Ancona (Italy); Focardi, Silvano [Department of Environmental Sciences ' G. Sarfatti' , University of Siena, Via Mattioli 4, 53100 Siena (Italy)

    2010-08-15

    Several ABC transporters have been characterized from many aquatic organisms, but no information is yet available for Antarctic fish. The aim of this work was to identify the expression of genes for ABC proteins in Trematomus bernacchii, a bioindicator species of the Southern Ocean. Partial cDNA sequences of ABCB1, ABCC1, ABCC2, ABCC4 and ABCC9 were cloned from liver. Using RACE technology, 3.5 and 2.2 kb contigs were obtained for ABCB1 and ABCC2. Considering the elevated natural bioavailability of cadmium at Terra Nova Bay, responsiveness of ABCB1 and ABCC2 to this element was investigated under laboratory conditions. ABCB1 and ABCC2 mRNA levels were approximately four-fold higher in Cd-exposed fish compared to the controls. Induction of ABCB1 protein was also found by western blot. This study provides the first identification of five ABC genes in the liver of an Antarctic key species, some of which may be involved in cellular detoxification. - The presence of five partial sequences showing homology with ABC transporters and the sensitivity of ABCB1 and ABCC2 toward cadmium were determined in the liver of T. bernacchii.

  2. ATP-binding Cassette (ABC) Transport System Solute-binding Protein-guided Identification of Novel d-Altritol and Galactitol Catabolic Pathways in Agrobacterium tumefaciens C58.

    Science.gov (United States)

    Wichelecki, Daniel J; Vetting, Matthew W; Chou, Liyushang; Al-Obaidi, Nawar; Bouvier, Jason T; Almo, Steven C; Gerlt, John A

    2015-11-27

    Innovations in the discovery of the functions of uncharacterized proteins/enzymes have become increasingly important as advances in sequencing technology flood protein databases with an exponentially growing number of open reading frames. This study documents one such innovation developed by the Enzyme Function Initiative (EFI; U54GM093342), the use of solute-binding proteins for transport systems to identify novel metabolic pathways. In a previous study, this strategy was applied to the tripartite ATP-independent periplasmic transporters. Here, we apply this strategy to the ATP-binding cassette transporters and report the discovery of novel catabolic pathways for d-altritol and galactitol in Agrobacterium tumefaciens C58. These efforts resulted in the description of three novel enzymatic reactions as follows: 1) oxidation of d-altritol to d-tagatose via a dehydrogenase in Pfam family PF00107, a previously unknown reaction; 2) phosphorylation of d-tagatose to d-tagatose 6-phosphate via a kinase in Pfam family PF00294, a previously orphan EC number; and 3) epimerization of d-tagatose 6-phosphate C-4 to d-fructose 6-phosphate via a member of Pfam family PF08013, another previously unknown reaction. The epimerization reaction catalyzed by a member of PF08013 is especially noteworthy, because the functions of members of PF08013 have been unknown. These discoveries were assisted by the following two synergistic bioinformatics web tools made available by the Enzyme Function Initiative: the EFI-Enzyme Similarity Tool and the EFI-Genome Neighborhood Tool. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. ATP-binding Cassette (ABC) Transport System Solute-binding Protein-guided Identification of Novel d-Altritol and Galactitol Catabolic Pathways in Agrobacterium tumefaciens C58*

    Science.gov (United States)

    Wichelecki, Daniel J.; Vetting, Matthew W.; Chou, Liyushang; Al-Obaidi, Nawar; Bouvier, Jason T.; Almo, Steven C.; Gerlt, John A.

    2015-01-01

    Innovations in the discovery of the functions of uncharacterized proteins/enzymes have become increasingly important as advances in sequencing technology flood protein databases with an exponentially growing number of open reading frames. This study documents one such innovation developed by the Enzyme Function Initiative (EFI; U54GM093342), the use of solute-binding proteins for transport systems to identify novel metabolic pathways. In a previous study, this strategy was applied to the tripartite ATP-independent periplasmic transporters. Here, we apply this strategy to the ATP-binding cassette transporters and report the discovery of novel catabolic pathways for d-altritol and galactitol in Agrobacterium tumefaciens C58. These efforts resulted in the description of three novel enzymatic reactions as follows: 1) oxidation of d-altritol to d-tagatose via a dehydrogenase in Pfam family PF00107, a previously unknown reaction; 2) phosphorylation of d-tagatose to d-tagatose 6-phosphate via a kinase in Pfam family PF00294, a previously orphan EC number; and 3) epimerization of d-tagatose 6-phosphate C-4 to d-fructose 6-phosphate via a member of Pfam family PF08013, another previously unknown reaction. The epimerization reaction catalyzed by a member of PF08013 is especially noteworthy, because the functions of members of PF08013 have been unknown. These discoveries were assisted by the following two synergistic bioinformatics web tools made available by the Enzyme Function Initiative: the EFI-Enzyme Similarity Tool and the EFI-Genome Neighborhood Tool. PMID:26472925

  4. Mechanisms involved in the transport of mercuric ions in target tissues

    Science.gov (United States)

    Bridges, Christy C.; Zalups, Rudolfs K.

    2016-01-01

    Mercury exists in the environment in various forms, all of which pose a risk to human health. Despite guidelines regulating the industrial release of mercury into the environment, humans continue to be exposed regularly to various forms of this metal via inhalation or ingestion. Following exposure, mercuric ions are taken up by and accumulate in numerous organs, including brain, intestine, kidney, liver, and placenta. In order to understand the toxicological effects of exposure to mercury, a thorough understanding of the mechanisms that facilitate entry of mercuric ions into target cells must first be obtained. A number of mechanisms for the transport of mercuric ions into target cells and organs have been proposed in recent years. However, the ability of these mechanisms to transport mercuric ions and the regulatory features of these carriers have not been characterized completely. The purpose of this review is to summarize the current findings related to the mechanisms that may be involved in the transport of inorganic and organic forms of mercury in target tissues and organs. This review will describe mechanisms known to be involved in the transport of mercury and will also propose additional mechanisms that may potentially be involved in the transport of mercuric ions into target cells. PMID:27422290

  5. Assessment of the radiological risks of road transport accidents involving type A package shipments

    International Nuclear Information System (INIS)

    Lange, F.; Fett, H.J.; Schwarz, G.; Raffestin, D.; Schneider, T.; Gelder, R.; Hughes, J.S.; Shaw, K.B.; Hedberg, B.; Simenstad, P.; Svahn, B.; Hienen, J.F.A.; Jansma, R.

    1998-01-01

    This paper is an account of work performed within a multi-lateral research project on the radiological risks associated with the transportation of Type A packaged radioactive material. The research project has been performed on behalf of the European Commission and various national agencies of the participating countries and involved organizations and institutes of five EU Member States, France, Germany, The Netherlands, Sweden, and the UK. The main objectives of the research project were the assessment and appraisal of the potential radiological risks of road transport accidents involving Type A package shipments in participating EU Member States. Data were collected and include harmonized sets information related to the type, quantity and characteristics of Type A package shipments by road. Such databases were basically non-existent until recently. The results are expected to be valuable to both national agencies and international organizations, with responsibilities for the safe transport of radioactive materials by providing some insight in the carriage of radioactive materials by road making up a major fraction of radioactive material transports. Similarly, a wide body of information has been collected and compiled on road transport accidents in terms of the frequency of occurrence and the severity of accidental impact loads potentially experienced by a Type A package.In addition, the results will facilitate judgement of the adequacy of the IAEA Transport Regulations as far as Type A packages are concerned. (O.M.)

  6. Inhibition of the Human ABC Efflux Transporters P-gp and BCRP by the BDE-47 Hydroxylated Metabolite 6-OH-BDE-47: Considerations for Human Exposure

    Science.gov (United States)

    High body burdens of polybrominated diphenyl ethers (PBDEs) in infants and young children have led to increased concern over their potential impact on human development. PBDE exposure can alter the expression of genes involved in thyroid homeostasis, including those of ATP-bindin...

  7. Effects of Deletion of the Streptococcus pneumoniae Lipoprotein Diacylglyceryl Transferase Gene lgt on ABC Transporter Function and on Growth In Vivo.

    NARCIS (Netherlands)

    Chimalapati, S.; Cohen, J.M.; Camberlein, E.; Macdonald, N.; Durmort, C.; Vernet, T.; Hermans, P.W.M.; Mitchell, T.; Brown, J.S.

    2012-01-01

    Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt), deletion of the

  8. Down-regulation of aminopeptidase N and ABC transporter subfamily G transcripts in Cry1Ab and Cry1Ac resistant Asian corn borer, Ostrina furnacalis (Lepidoptera: Crambidae)

    Science.gov (United States)

    Bacillus thuringiensis (Bt) crystalline protein (Cry) toxins cause mortality by a mechanism involving pore formation or signal transduction following toxin binding to receptors along the midgut lumen of susceptible insects, but this mechanism and mutations therein that lead to resistance remain poor...

  9. The Role of ABC Proteins in Drug Resistant Breast Cancer Cells

    National Research Council Canada - National Science Library

    Lekostaj, Jacqueline K

    2008-01-01

    ...) of the Office of the Congressionally Directed Medical Research Programs (CDMRP), aims to study the possible role of ABC transporters in pleitropic drug resistance, using a combination of molecular biological, biochemical, and biophysical methods...

  10. Identification of functional amino acid residues involved in polyamine and agmatine transport by human organic cation transporter 2.

    Directory of Open Access Journals (Sweden)

    Kyohei Higashi

    Full Text Available Polyamine (putrescine, spermidine and spermine and agmatine uptake by the human organic cation transporter 2 (hOCT2 was studied using HEK293 cells transfected with pCMV6-XL4/hOCT2. The Km values for putrescine and spermidine were 7.50 and 6.76 mM, and the Vmax values were 4.71 and 2.34 nmol/min/mg protein, respectively. Spermine uptake by hOCT2 was not observed at pH 7.4, although it inhibited both putrescine and spermidine uptake. Agmatine was also taken up by hOCT2, with Km value: 3.27 mM and a Vmax value of 3.14 nmol/min/mg protein. Amino acid residues involved in putrescine, agmatine and spermidine uptake by hOCT2 were Asp427, Glu448, Glu456, Asp475, and Glu516. In addition, Glu524 and Glu530 were involved in putrescine and spermidine uptake activity, and Glu528 and Glu540 were weakly involved in putrescine uptake activity. Furthermore, Asp551 was also involved in the recognition of spermidine. These results indicate that the recognition sites for putrescine, agmatine and spermidine on hOCT2 strongly overlap, consistent with the observation that the three amines are transported with similar affinity and velocity. A model of spermidine binding to hOCT2 was constructed based on the functional amino acid residues.

  11. Identification of Functional Amino Acid Residues Involved in Polyamine and Agmatine Transport by Human Organic Cation Transporter 2

    Science.gov (United States)

    Higashi, Kyohei; Imamura, Masataka; Fudo, Satoshi; Uemura, Takeshi; Saiki, Ryotaro; Hoshino, Tyuji; Toida, Toshihiko; Kashiwagi, Keiko; Igarashi, Kazuei

    2014-01-01

    Polyamine (putrescine, spermidine and spermine) and agmatine uptake by the human organic cation transporter 2 (hOCT2) was studied using HEK293 cells transfected with pCMV6-XL4/hOCT2. The Km values for putrescine and spermidine were 7.50 and 6.76 mM, and the Vmax values were 4.71 and 2.34 nmol/min/mg protein, respectively. Spermine uptake by hOCT2 was not observed at pH 7.4, although it inhibited both putrescine and spermidine uptake. Agmatine was also taken up by hOCT2, with Km value: 3.27 mM and a Vmax value of 3.14 nmol/min/mg protein. Amino acid residues involved in putrescine, agmatine and spermidine uptake by hOCT2 were Asp427, Glu448, Glu456, Asp475, and Glu516. In addition, Glu524 and Glu530 were involved in putrescine and spermidine uptake activity, and Glu528 and Glu540 were weakly involved in putrescine uptake activity. Furthermore, Asp551 was also involved in the recognition of spermidine. These results indicate that the recognition sites for putrescine, agmatine and spermidine on hOCT2 strongly overlap, consistent with the observation that the three amines are transported with similar affinity and velocity. A model of spermidine binding to hOCT2 was constructed based on the functional amino acid residues. PMID:25019617

  12. Ion transporters involved in acidification of the resorption lacuna in osteoclasts

    DEFF Research Database (Denmark)

    Henriksen, K.; Sorensen, M.G.; Jensen, V.K.

    2008-01-01

    Osteoclasts possess a large amount of ion transporters, which participate in bone resorption; of these, the vacuolar-adenosine trisphosphatase (V-ATPase) and the chloride-proton antiporter ClC-7 acidify the resorption lacuna. However, whether other ion transporters participate in this process is ......, including carbonic anhydrase II, the NHEs, and potassium-chloride cotransporters, are all involved in resorption but do not seem to directly be involved in acidification of the lysosomes Udgivelsesdato: 2008/9...... experiments, or (4) lysed in trizol for mRNA isolation for Affymetrix array analysis. Inhibitors targeted toward most of the ion transporters showed low potency in the acidification-based assays, although some inhibitors, such as carbonic anhydrase II and the sodium-hydrogen exchanger (NHE) inhibitors...

  13. Identification of the cells involved in auxin transport in maize mesocotyl

    International Nuclear Information System (INIS)

    Jones, A.M.

    1989-01-01

    A study was undertaken to identify by a direct method the cells involved in auxin transport through maize mesocotyl tissue. The auxin photoaffinity labeling agent, 7-[ 3 H], 5-azidoindole 3-acetic acid (N 3 IAA), was loaded into excised stem tissue from a cut end. Polar transport of this analog was demonstrated over 4 hours by comparing uptake into tissue loaded with N 3 IAA from the apical vs. the basal end. Triiodobenzoic acid, an auxin transport inhibitor, inhibited N 3 IAA uptake into tissue. Tissue which had taken up the photoaffinity labeling agent was photolyzed to covalently fix the radioisotope within cells. This tissue was sectioned and subjected to in situ autoradiography. The outermost cell of epidermal tissue and certain files of cells in vascular tissue were densely labeled indicating that on a per cell basis these two cell types are most actively transporting auxin

  14. Status of transport events involving radioactive materials which occurred in France between 1999 and 2011

    International Nuclear Information System (INIS)

    2013-01-01

    This report presents transport events involving radioactive materials, occurred on French territory from 1999 to 2011, listed in the IRSN's database. 1,304 events have been recorded. For each of them, many parameters have been collected and analysed from information listed in the notifications and reports of the events sent by users (type of event, purpose, package design, level on the INES scale...). The numbers of events notified in 2010 and 2011 are slightly higher than the average of 100 events per year. The two main causes of notification concern documentation errors (in transport documents or labeling) and handling mishaps. The downward trend of frequency of package or conveyance contaminations has been confirmed. A short description of the outstanding events occurred in 2010 and 2011 is proposed. This synthesis also gives an outline of the actions recommended by IRSN to avoid recurrence of the notified events and improve the safety of the transports of radioactive materials

  15. Identification and expression analysis of MATE genes involved in flavonoid transport in blueberry plants.

    Science.gov (United States)

    Chen, Li; Liu, Yushan; Liu, Hongdi; Kang, Limin; Geng, Jinman; Gai, Yuzhuo; Ding, Yunlong; Sun, Haiyue; Li, Yadong

    2015-01-01

    Multidrug and toxic compound extrusion (MATE) proteins are the most recently identified family of multidrug transporters. In plants, this family is remarkably large compared to the human and bacteria counterpart, highlighting the importance of MATE proteins in this kingdom. Here 33 Unigenes annotated as MATE transporters were found in the blueberry fruit transcriptome, of which eight full-length cDNA sequences were identified and cloned. These proteins are composed of 477-517 residues, with molecular masses ~54 kDa, and theoretical isoelectric points from 5.35 to 8.41. Bioinformatics analysis predicted 10-12 putative transmembrane segments for VcMATEs, and localization to the plasma membrane without an N-terminal signal peptide. All blueberry MATE proteins shared 32.1-84.4% identity, among which VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8, and VcMATE9 were more similar to the MATE-type flavonoid transporters. Phylogenetic analysis showed VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8 and VcMATE9 clustered with MATE-type flavonoid transporters, indicating that they might be involved in flavonoid transport. VcMATE1 and VcMATE4 may be involved in the transport of secondary metabolites, the detoxification of xenobiotics, or the export of toxic cations. Real-time quantitative PCR demonstrated that the expression profile of the eight VcMATE genes varied spatially and temporally. Analysis of expression and anthocyanin accumulation indicated that there were some correlation between the expression profile and the accumulation of anthocyanins. These results showed VcMATEs might be involved in diverse physiological functions, and anthocyanins across the membranes might be mutually maintained by MATE-type flavonoid transporters and other mechanisms. This study will enrich the MATE-based transport mechanisms of secondary metabolite, and provide a new biotechonology strategy to develop better nutritional blueberry cultivars.

  16. Decision process involved in preparing the Shippingport reactor pressure vessel for transport

    International Nuclear Information System (INIS)

    Murphie, W.E.

    1989-01-01

    The most significant part of the Shippingport Station Decommissioning Project was the one-piece removal and shipment of the reactor pressure vessel (RPV). Implicit in the RPV transport was the task of qualifying the RPV as a waste package acceptable for shipment. Soon after physical decommissioning began on September 1985, questions regarding the packaging certification and transport of the RPV from Shippingport, Pennsylvania to the US Department of Energy (DOE) Hanford Waste Burial Site necessitated reexamination of several planning assumptions. A complete reassessment of the regulatory requirements governing the RPV shipment resulted in a programmatic decision to obtain a type B(U) Certificate of Compliance and abandon the originally planned US Department of Transportation (DOT) low specific activity (LSA) shipment. The decision process resulting in this conclusion was extensive and involved many organizations and agencies. Incidental to this process, several subtle certification issues were identified that required resolution. Some of these issues involved the definition of LSA material for large packages; interpretation and compliance with DOE, DOT and US Nuclear Regulatory Commission (NRC) regulations for the transport of radioactive material; incorporation of the International Atomic Energy Agency (IAEA) regulations by the Panama Canal; and DOE policy requiring advance notification to states of radioactive waste shipments. 2 figs

  17. Decision process involved in preparing the Shippingport reactor pressure vessel for transport

    International Nuclear Information System (INIS)

    Murphie, W.E.

    1990-01-01

    The most significant part of the Shippingport Station Decommissioning Project was the one-piece removal and shipment of the reactor pressure vessel (RPV). Implicit in the RPV transport was the task of qualifying the RPV as a waste package acceptable for shipment. Soon after physical decommissioning began on September, 1985, questions regarding the packaging certification and transport of the RPV from Shippingport, Pennsylvania to the U.S. Department of Energy (DOE) Hanford waste burial site necessitated reexamination of several planning assumptions. A complete reassessment of the regulatory requirements governing the RPV shipment resulting in a programmatic decision to obtain a Type B(U) Certification of Compliance and abandon the originally planned U.S. Department of Transportation (DOT) low specific activity (LSA) shipment. The decision process resulting in this conclusion was extensive and involved many organizations and agencies. Incidental to this process, several subtle certification issues were identified that required resolution. Some of these issues involved the definition of LSA material for large packages; interpretation and compliance with DOE, DOT and U.S. Nuclear Regulatory Commission (NRC) regulations for the transport of radioactive material; incorporation of the International Atomic Energy Agency (IAEA) regulations by the Panama Canal; and DOE policy requiring advance notification to states of radioactive waste shipments

  18. Identification of a transporter Slr0982 involved in ethanol tolerance in cyanobacterium Synechocystis sp. PCC 6803

    Directory of Open Access Journals (Sweden)

    Yanan eZhang

    2015-05-01

    Full Text Available Cyanobacteria have been engineered to produce ethanol through recent synthetic biology efforts. However, one major challenge to the cyanobacterial systems for high-efficiency ethanol production is their low tolerance to the ethanol toxicity. With a major goal to identify novel transporters involved in ethanol tolerance, we constructed gene knockout mutants for 58 transporter-encoding genes of Synechocystis sp. PCC 6803 and screened their tolerance change under ethanol stress. The efforts allowed discovery of a mutant of slr0982 gene encoding an ATP-binding cassette transporter which grew poorly in BG11 medium supplemented with 1.5% (v/v ethanol when compared with the wild type, and the growth loss could be recovered by complementing slr0982 in the ∆slr0982 mutant, suggesting that slr0982 is involved in ethanol tolerance in Synechocystis. To decipher the tolerance mechanism involved, a comparative metabolomic and network-based analysis of the wild type and the ethanol-sensitive ∆slr0982 mutant was performed. The analysis allowed the identification of four metabolic modules related to slr0982 deletion in the ∆slr0982 mutant, among which metabolites like sucrose and L-pyroglutamic acid which might be involved in ethanol tolerance, were found important for slr0982 deletion in the ∆slr0982 mutant. This study reports on the first transporter related to ethanol tolerance in Synechocystis, which could be a useful target for further tolerance engineering. In addition, metabolomic and network analysis provides important findings for better understanding of the tolerance mechanism to ethanol stress in Synechocystis.

  19. Emergency response planning and preparedness for transport accidents involving radioactive material

    International Nuclear Information System (INIS)

    1988-01-01

    The purpose of this Guide is to provide assistance to public authorities and others (including consignors and carriers of radioactive materials) who are responsible for ensuring safety in establishing and developing emergency response arrangements for responding effectively to transport accidents involving radioactive materials. This Guide is concerned mainly with the preparation of emergency response plans. It provides information which will assist those countries whose involvement with radioactive materials is just beginning and those which have already developed their industries involving radioactive materials and attendant emergency plans, but may need to review and improve these plans. The need for emergency response plans and the ways in which they are implemented vary from country to country. In each country, the responsible authorities must decide how best to apply this Guide, taking into account the actual shipments and associated hazards. In this Guide the emergency response planning and response philosophy are outlined, including identification of emergency response organizations and emergency services that would be required during a transport accident. General consequences which could prevail during an accident are described taking into account the IAEA Regulations for the Safe Transport of Radioactive Material. 43 refs, figs and tabs

  20. Paraquat Resistant1, a Golgi-localized putative transporter protein, is involved in intracellular transport of paraquat.

    Science.gov (United States)

    Li, Jianyong; Mu, Jinye; Bai, Jiaoteng; Fu, Fuyou; Zou, Tingting; An, Fengying; Zhang, Jian; Jing, Hongwei; Wang, Qing; Li, Zhen; Yang, Shuhua; Zuo, Jianru

    2013-05-01

    Paraquat is one of the most widely used herbicides worldwide. In green plants, paraquat targets the chloroplast by transferring electrons from photosystem I to molecular oxygen to generate toxic reactive oxygen species, which efficiently induce membrane damage and cell death. A number of paraquat-resistant biotypes of weeds and Arabidopsis (Arabidopsis thaliana) mutants have been identified. The herbicide resistance in Arabidopsis is partly attributed to a reduced uptake of paraquat through plasma membrane-localized transporters. However, the biochemical mechanism of paraquat resistance remains poorly understood. Here, we report the identification and characterization of an Arabidopsis paraquat resistant1 (par1) mutant that shows strong resistance to the herbicide without detectable developmental abnormalities. PAR1 encodes a putative l-type amino acid transporter protein localized to the Golgi apparatus. Compared with the wild-type plants, the par1 mutant plants show similar efficiency of paraquat uptake, suggesting that PAR1 is not directly responsible for the intercellular uptake of paraquat. However, the par1 mutation caused a reduction in the accumulation of paraquat in the chloroplast, suggesting that PAR1 is involved in the intracellular transport of paraquat into the chloroplast. We identified a PAR1-like gene, OsPAR1, in rice (Oryza sativa). Whereas the overexpression of OsPAR1 resulted in hypersensitivity to paraquat, the knockdown of its expression using RNA interference conferred paraquat resistance on the transgenic rice plants. These findings reveal a unique mechanism by which paraquat is actively transported into the chloroplast and also provide a practical approach for genetic manipulations of paraquat resistance in crops.

  1. The ABCs of particle physics

    CERN Document Server

    Biron, Lauren

    2016-01-01

    For lovers of rhymes and anthropomorphic Higgs bosons, Symmetry presents its first published board book, The ABCs of Particle Physics. Use it as an illustrated guide to basic particle- and astrophysics terms, or read it to your infant at bedtime, if you don’t mind their first word being “quark.”

  2. Involvement of intracellular transport in TREK-1c current run-up in 293T cells.

    Science.gov (United States)

    Andharia, Naaz; Joseph, Ancy; Hayashi, Mikio; Okada, Masayoshi; Matsuda, Hiroko

    2017-05-04

    The TREK-1 channel, the TWIK-1-related potassium (K + ) channel, is a member of a family of 2-pore-domain K + (K2P) channels, through which background or leak K + currents occur. An interesting feature of the TREK-1 channel is the run-up of current: i.e. the current through TREK-1 channels spontaneously increases within several minutes of the formation of the whole-cell configuration. To investigate whether intracellular transport is involved in the run-up, we established 293T cell lines stably expressing the TREK-1c channel (K2P2.1) and examined the effects of inhibitors of membrane protein transport, N-methylmaleimide (NEM), brefeldin-A, and an endocytosis inhibitor, pitstop2, on the run-up. The results showing that NEM and brefeldin-A inhibited and pitstop2 facilitated the run-up suggest the involvement of intracellular protein transport. Correspondingly, in cells stably expressing the mCherry-TREK-1 fusion protein, NEM decreased and pitstop2 increased the cell surface localization of the fusion protein. Furthermore, the run-up was inhibited by the intracellular application of a peptide of the C-terminal fragment TREK335-360, corresponding to the interaction site with microtubule-associated protein 2 (Mtap2). This peptide also inhibited the co-immunoprecipitation of Mtap2 with anti-mCherry antibody. The extracellular application of an ezrin inhibitor (NSC668394) also suppressed the run-up and surface localization of the fusion protein. The co-application of these inhibitors abolished the TREK-1c current, suggesting that the additive effects of ezrin and Mtap2 enhance the surface expression of TREK-1c channels and the run-up. These findings clearly showed the involvement of intracellular transport in TREK-1c current run-up and its mechanism.

  3. A solute-binding protein for iron transport in Streptococcus iniae

    Directory of Open Access Journals (Sweden)

    Li Anxing

    2010-12-01

    Full Text Available Abstract Background Streptococcus iniae (S. iniae is a major pathogen that causes considerable morbidity and mortality in cultured fish worldwide. The pathogen's ability to adapt to the host affects the extent of infection, hence understanding the mechanisms by which S. iniae overcomes physiological stresses during infection will help to identify potential virulence determinants of streptococcal infection. Grow S. iniae under iron-restricted conditions is one approach for identifying host-specific protein expression. Iron plays an important role in many biological processes but it has low solubility under physiological condition. Many microorganisms have been shown to be able to circumvent this nutritional limitation by forming direct contacts with iron-containing proteins through ATP-binding cassette (ABC transporters. The ABC transporter superfamilies constitute many different systems that are widespread among living organisms with different functions, such as ligands translocation, mRNA translation, and DNA repair. Results An ABC transporter system, named as mtsABC (metal transport system was cloned from S. iniae HD-1, and was found to be involved in heme utilization. mtsABC is cotranscribed by three downstream genes, i.e., mtsA, mtsB, and mtsC. In this study, we cloned the first gene of the mtsABC transporter system (mtsA, and purified the corresponding recombinant protein MtsA. The analysis indicated that MtsA is a putative lipoprotein which binds to heme that can serve as an iron source for the microorganism, and is expressed in vivo during Kunming mice infection by S. iniae HD-1. Conclusions This is believed to be the first report on the cloning the ABC transporter lipoprotein from S. iniae genomic DNA. Together, our data suggested that MtsA is associated with heme, and is expressed in vivo during Kunming mice infection by S. iniae HD-1 which indicated that it can be a potential candidate for S. iniae subunit vaccine.

  4. A 6-Nucleotide Regulatory Motif within the AbcR Small RNAs of Brucella abortus Mediates Host-Pathogen Interactions

    Science.gov (United States)

    Sheehan, Lauren M.

    2017-01-01

    ABSTRACT In Brucella abortus, two small RNAs (sRNAs), AbcR1 and AbcR2, are responsible for regulating transcripts encoding ABC-type transport systems. AbcR1 and AbcR2 are required for Brucella virulence, as a double chromosomal deletion of both sRNAs results in attenuation in mice. Although these sRNAs are responsible for targeting transcripts for degradation, the mechanism utilized by the AbcR sRNAs to regulate mRNA in Brucella has not been described. Here, two motifs (M1 and M2) were identified in AbcR1 and AbcR2, and complementary motif sequences were defined in AbcR-regulated transcripts. Site-directed mutagenesis of M1 or M2 or of both M1 and M2 in the sRNAs revealed transcripts to be targeted by one or both motifs. Electrophoretic mobility shift assays revealed direct, concentration-dependent binding of both AbcR sRNAs to a target mRNA sequence. These experiments genetically and biochemically characterized two indispensable motifs within the AbcR sRNAs that bind to and regulate transcripts. Additionally, cellular and animal models of infection demonstrated that only M2 in the AbcR sRNAs is required for Brucella virulence. Furthermore, one of the M2-regulated targets, BAB2_0612, was found to be critical for the virulence of B. abortus in a mouse model of infection. Although these sRNAs are highly conserved among Alphaproteobacteria, the present report displays how gene regulation mediated by the AbcR sRNAs has diverged to meet the intricate regulatory requirements of each particular organism and its unique biological niche. PMID:28588127

  5. H{sup +}/peptide transporter (PEPT2) is expressed in human epidermal keratinocytes and is involved in skin oligopeptide transport

    Energy Technology Data Exchange (ETDEWEB)

    Kudo, Michiko; Katayoshi, Takeshi; Kobayashi-Nakamura, Kumiko [DHC Corporation Laboratories, Division 2, 2-42 Hamada, Mihama-ku, Chiba 261-0025 (Japan); Akagawa, Mitsugu [Department of Biological Chemistry, Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan); Tsuji-Naito, Kentaro, E-mail: knaito@dhc.co.jp [DHC Corporation Laboratories, Division 2, 2-42 Hamada, Mihama-ku, Chiba 261-0025 (Japan)

    2016-07-08

    Peptide transporter 2 (PEPT2) is a member of the proton-coupled oligopeptide transporter family, which mediates the cellular uptake of oligopeptides and peptide-like drugs. Although PEPT2 is expressed in many tissues, its expression in epidermal keratinocytes remains unclear. We investigated PEPT2 expression profile and functional activity in keratinocytes. We confirmed PEPT2 mRNA expression in three keratinocyte lines (normal human epidermal keratinocytes (NHEKs), immortalized keratinocytes, and malignant keratinocytes) by reverse transcription-polymerase chain reaction (RT-PCR) and quantitative real-time RT-PCR. In contrast to PEPT1, PEPT2 expression in the three keratinocytes was similar or higher than that in HepG2 cells, used as PEPT2-positive cells. Immunolocalization analysis using human skin showed epidermal PEPT2 localization. We studied keratinocyte transport function by measuring the oligopeptide content using liquid chromatography/tandem mass spectrometry. Glycylsarcosine uptake in NHEKs was pH-dependent, suggesting that keratinocytes could absorb small peptides in the presence of an inward H{sup +} gradient. We also performed a skin-permeability test of several oligopeptides using skin substitute, suggesting that di- and tripeptides pass actively through the epidermis. In conclusion, PEPT2 is expressed in keratinocytes and involved in skin oligopeptide uptake. -- Highlights: •PEPT2 is expressed in keratinocytes, which are more common than other skin cells. •Immunolocalization analysis using human skin revealed epidermal PEPT2 localization. •Keratinocytes could absorb small peptides in the presence of an inward H{sup +} gradient. •Di- and tripeptide pass actively through the epidermis.

  6. Development of supporting system for emergency response to maritime transport accidents involving radioactive material

    International Nuclear Information System (INIS)

    Odano, N.; Matsuoka, T.; Suzuki, H.

    2004-01-01

    National Maritime Research Institute has developed a supporting system for emergency response of competent authority to maritime transport accidents involving radioactive material. The supporting system for emergency response has functions of radiation shielding calculation, marine diffusion simulation, air diffusion simulation and radiological impact evaluation to grasp potential hazard of radiation. Loss of shielding performance accident and loss of sealing ability accident were postulated and impact of the accidents was evaluated based on the postulated accident scenario. Procedures for responding to emergency were examined by the present simulation results

  7. A 6-Nucleotide Regulatory Motif within the AbcR Small RNAs of Brucella abortus Mediates Host-Pathogen Interactions.

    Science.gov (United States)

    Sheehan, Lauren M; Caswell, Clayton C

    2017-06-06

    In Brucella abortus , two small RNAs (sRNAs), AbcR1 and AbcR2, are responsible for regulating transcripts encoding ABC-type transport systems. AbcR1 and AbcR2 are required for Brucella virulence, as a double chromosomal deletion of both sRNAs results in attenuation in mice. Although these sRNAs are responsible for targeting transcripts for degradation, the mechanism utilized by the AbcR sRNAs to regulate mRNA in Brucella has not been described. Here, two motifs (M1 and M2) were identified in AbcR1 and AbcR2, and complementary motif sequences were defined in AbcR-regulated transcripts. Site-directed mutagenesis of M1 or M2 or of both M1 and M2 in the sRNAs revealed transcripts to be targeted by one or both motifs. Electrophoretic mobility shift assays revealed direct, concentration-dependent binding of both AbcR sRNAs to a target mRNA sequence. These experiments genetically and biochemically characterized two indispensable motifs within the AbcR sRNAs that bind to and regulate transcripts. Additionally, cellular and animal models of infection demonstrated that only M2 in the AbcR sRNAs is required for Brucella virulence. Furthermore, one of the M2-regulated targets, BAB2_0612, was found to be critical for the virulence of B. abortus in a mouse model of infection. Although these sRNAs are highly conserved among Alphaproteobacteria , the present report displays how gene regulation mediated by the AbcR sRNAs has diverged to meet the intricate regulatory requirements of each particular organism and its unique biological niche. IMPORTANCE Small RNAs (sRNAs) are important components of bacterial regulation, allowing organisms to quickly adapt to changes in their environments. The AbcR sRNAs are highly conserved throughout the Alphaproteobacteria and negatively regulate myriad transcripts, many encoding ABC-type transport systems. In Brucella abortus , AbcR1 and AbcR2 are functionally redundant, as only a double abcR1 abcR2 ( abcR1 / 2 ) deletion results in attenuation in

  8. Wireless technology for ABC Assessment

    DEFF Research Database (Denmark)

    Kristensen, Margit; Kyng, Morten; Christensen, Erika Frischknecht

    be just beside a victim to assess the ABC status. Consequently - in situations with many victims - monitoring equipment is only used for the (few) most seriously injured. Our ongoing research builds on data collected through extensive field studies and is described in several published papers. We......  In medical emergency service (EMS) the ABC status (Airway-Breathing-Circulation) of victims is essential in the decision making process regarding prioritizing and treatment. Today's use of information technology does, however, not inform directly about "A" and "B". The parameters are evaluated...... indirectly through assessment of collected biosensor data, such as ECG, and directly by the rescuer regarding how the patient looks and sounds. Moreover, the monitoring equipment used today is connected with displays by wires and thus only utilizes one display at a time. This means that the rescuers must...

  9. The GARP Complex Is Involved in Intracellular Cholesterol Transport via Targeting NPC2 to Lysosomes.

    Science.gov (United States)

    Wei, Jian; Zhang, Ying-Yu; Luo, Jie; Wang, Ju-Qiong; Zhou, Yu-Xia; Miao, Hong-Hua; Shi, Xiong-Jie; Qu, Yu-Xiu; Xu, Jie; Li, Bo-Liang; Song, Bao-Liang

    2017-06-27

    Proper intracellular cholesterol trafficking is critical for cellular function. Two lysosome-resident proteins, NPC1 and NPC2, mediate the egress of low-density lipoprotein-derived cholesterol from lysosomes. However, other proteins involved in this process remain largely unknown. Through amphotericin B-based selection, we isolated two cholesterol transport-defective cell lines. Subsequent whole-transcriptome-sequencing analysis revealed two cell lines bearing the same mutation in the vacuolar protein sorting 53 (Vps53) gene. Depletion of VPS53 or other subunits of the Golgi-associated retrograde protein (GARP) complex impaired NPC2 sorting to lysosomes and caused cholesterol accumulation. GARP deficiency blocked the retrieval of the cation-independent mannose 6-phosphate receptor (CI-MPR) to the trans-Golgi network. Further, Vps54 mutant mice displayed reduced cellular NPC2 protein levels and increased cholesterol accumulation, underscoring the physiological role of the GARP complex in cholesterol transport. We conclude that the GARP complex contributes to intracellular cholesterol transport by targeting NPC2 to lysosomes in a CI-MPR-dependent manner. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  10. INVENTORY CLASSIFICATION WITH ABC ANALYSIS

    OpenAIRE

    Kıyak, Erkan; Timuş, Oğuz Han; Karayel, Mehmet

    2015-01-01

    For a substantial organization, managing the expansive inventory is a serious problem. One of the methods to solve this problem used widely is classifying the inventory according to some criteria and managing inventory according to this classisifation. In this study, ABC classification methods are researched and Ng's model, which is one of the most widely used, selected for further investigation. An illustrative example is presented to show the usability of the Ng's method.

  11. Function and regulation of ATP-binding cassette transport proteins involved in hepatobiliary transport (vol 12, pg 13, 2000)

    NARCIS (Netherlands)

    Hooiveld, GJEJ; van Montfoort, JE; Meijer, DKF; Muller, M

    Hepatobiliary transport of endogenous and exogenous compounds is mediated by the coordinated action of multiple transport systems present at the sinusoidal (basolateral) and canalicular (apical) membrane domains of hepatocytes. During the last few years many of these transporters have been cloned

  12. An inventory of the human ABC proteins.

    Science.gov (United States)

    Klein, I; Sarkadi, B; Váradi, A

    1999-12-06

    Currently 30 human ABC proteins are represented by full sequences in various databases, and this paper provides a brief overview of these proteins. ABC proteins are composed of transmembrane domains (TMDs), and nucleotide binding domains (NBDs, or ATP-binding cassettes, ABSs). The arrangement of these domains, together with available membrane topology models of the family members, are presented. Based on their sequence similarity scores, the members of the human ABC protein family can be grouped into eight subfamilies. At present the MDR/TAP, the ALD, the MRP/CFTR, the ABC1, the White, the RNAseL inhibitor, the ANSA, and the GCN20 subfamilies are identified. Mutations of many human ABC proteins are known to be causative in inherited diseases, and a short description of the molecular pathology of these ABC gene-related genetic diseases is also provided.

  13. Characterization of a novel domain ‘GATE’ in the ABC protein DrrA and its role in drug efflux by the DrrAB complex

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Han; Rahman, Sadia; Li, Wen; Fu, Guoxing; Kaur, Parjit, E-mail: pkaur@gsu.edu

    2015-03-27

    A novel domain, GATE (Glycine-loop And Transducer Element), is identified in the ABC protein DrrA. This domain shows sequence and structural conservation among close homologs of DrrA as well as distantly-related ABC proteins. Among the highly conserved residues in this domain are three glycines, G215, G221 and G231, of which G215 was found to be critical for stable expression of the DrrAB complex. Other conserved residues, including E201, G221, K227 and G231, were found to be critical for the catalytic and transport functions of the DrrAB transporter. Structural analysis of both the previously published crystal structure of the DrrA homolog MalK and the modeled structure of DrrA showed that G215 makes close contacts with residues in and around the Walker A motif, suggesting that these interactions may be critical for maintaining the integrity of the ATP binding pocket as well as the complex. It is also shown that G215A or K227R mutation diminishes some of the atomic interactions essential for ATP catalysis and overall transport function. Therefore, based on both the biochemical and structural analyses, it is proposed that the GATE domain, located outside of the previously identified ATP binding and hydrolysis motifs, is an additional element involved in ATP catalysis. - Highlights: • A novel domain ‘GATE’ is identified in the ABC protein DrrA. • GATE shows high sequence and structural conservation among diverse ABC proteins. • GATE is located outside of the previously studied ATP binding and hydrolysis motifs. • Conserved GATE residues are critical for stability of DrrAB and for ATP catalysis.

  14. LrABCF1, a GCN-type ATP-binding cassette transporter from Lilium regale, is involved in defense responses against viral and fungal pathogens.

    Science.gov (United States)

    Sun, Daoyang; Zhang, Xinguo; Li, Shaohua; Jiang, Cai-Zhong; Zhang, Yanlong; Niu, Lixin

    2016-12-01

    The L. regale ATP-binding cassette transporter gene, LrABCF1 belonging to GCN subfamily, functions as a positive regulator of plant defense against Cucumber mosaic virus, Tobacco rattle virus , and Botrytis cinerea in petunia. ATP-binding cassette (ABC) transporters are essential for membrane translocation in diverse biological processes, such as plant development and defense response. Here, a general control non-derepressible (GCN)-type ABC transporter gene, designated LrABCF1, was identified from Cucumber mosaic virus (CMV)-induced cDNA library of L. regale. LrABCF1 was up-regulated upon inoculation with CMV and Lily mottle virus (LMoV). Salicylic acid (SA) and ethylene (ET) application and treatments with abiotic stresses such as cold, high salinity, and wounding increased the transcript abundances of LrABCF1. Constitutive overexpression of LrABCF1 in petunia (Petunia × hybrida) resulted in an impairment of plant growth and development. LrABCF1 overexpression conferred reduced susceptibility to CMV, Tobacco rattle virus (TRV), and B. cinerea infection in transgenic petunia plants, accompanying by elevated transcripts of PhGCN2 and a few defense-related genes in SA-signaling pathway. Our data indicate that LrABCF1 positively modulates viral and fungal resistance.

  15. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast

    DEFF Research Database (Denmark)

    Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D.

    2014-01-01

    Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been i...

  16. Enterprise Architecture Data Pada Hotel ABC

    OpenAIRE

    Soesatyo, Stephanie; Wibowo, Adi; Handojo, Andreas

    2015-01-01

    Hotel ABC is a company engaged in hospitality management, i.e. room rental, rental of meeting rooms and coffee shop. Hotel ABC has a branch that has the same specifications of the hotel. In business process, Hotel ABC has information systems to support existing business processes. However, existing information systems have not been integrated as a whole. Based on the condition stated above, analysis and design of enterprise architecture information system is created for the company. The proce...

  17. Injuries in special transport services--situations and risk levels involving wheelchair users.

    Science.gov (United States)

    Wretstrand, Anders; Bylund, Per-Olof; Petzäll, Jan; Falkmer, Torbjörn

    2010-04-01

    Previous research has shown that wheelchair-seated passengers using special transportation services (STS) have been injured without being involved in a vehicle crash. In order to estimate incident rate and societal costs for these vehicle-related injuries, the focus needs to be adjusted towards a traveler/incident-oriented perspective. The aim of the project was to utilize such a perspective, related to travelers using STS in Sweden. In order to address the chosen perspective, a mixed method approach was used, involving quantitative as well as qualitative research techniques applied on four different sets of data: one hospital-based record, two sets of STS incident report databases, and interviews with wheelchair-seated STS passengers. The results showed that the injury incidence rate in STS is considerable, i.e. 10 per 100,000 trips. However, this high incidence rate is not due to road traffic collisions, but to non-collision injury incidents involving many elderly and frail passengers, who easily sustain traumas ranging from minor to moderate. The costs were estimated to be 23 million USD per annum or 14 USD per trip. Results suggest that future injury prevention measures should focus on safety in boarding and alighting procedures, as well as the continuing development of WTORS. Copyright 2009 IPEM. Published by Elsevier Ltd. All rights reserved.

  18. Scenario-based transportation planning with involvement of metropolitan planning organizations.

    Science.gov (United States)

    2009-01-01

    The Office of Virginia's Secretary of Transportation identified 21 transportation policies and 42 performance criteria in Virginia's long-range multimodal transportation plan, VTrans2025. A subsequent planning effort, VTrans2035, provided direction f...

  19. Uptake of perfluorooctanoic acid by Caco-2 cells: Involvement of organic anion transporting polypeptides.

    Science.gov (United States)

    Kimura, Osamu; Fujii, Yukiko; Haraguchi, Koichi; Kato, Yoshihisa; Ohta, Chiho; Koga, Nobuyuki; Endo, Tetsuya

    2017-08-05

    The mechanism underlying the intestinal absorption of perfluorooctanoic acid (PFOA) was investigated using Caco-2 cells. The uptake of PFOA from the apical membrane of Caco-2 cells was fast, and pH, temperature, and concentration dependent, but Na + independent. Coincubation with sulfobromophthalein (BSP), glibenclamide, estron-3-sulfate, cyclosporine A or rifamycin SV, which are typical substrates or inhibitors of organic anion transporting polypeptides (OATPs), significantly decreased the uptake of PFOA. However, coincubation with probenecid or p-aminohippuric acid, typical substrates of organic anion transporters, did not decrease the uptake of PFOA. Furthermore, coincubation with l-lactic acid or benzoic acid, substrates of monocarboxylic acid transporters, did not decrease PFOA uptake. The relationship between the initial uptake of PFOA and its concentration was saturable, suggesting the involvement of a carrier-mediated process. The calculated K m and uptake clearance (V max /K m ) values for PFOA were 8.3μM and 55.0μL/mg protein/min, respectively. This clearance value was about 3-fold greater than that of the non-saturable uptake clearance (K d : 18.1μL/mg protein/min). Lineweaver-Burk plots revealed that BSP competitively inhibits the uptake of PFOA, with a K i value of 23.1μM. These results suggest that the uptake of PFOA from the apical membranes of Caco-2 cells could be, at least in part, mediated by OATPs along with BSP. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Vacuolar iron transporter BnMEB2 is involved in enhancing iron tolerance of Brassica napus

    Directory of Open Access Journals (Sweden)

    Wei Zhu

    2016-09-01

    Full Text Available Iron toxicity is a major nutrient disorder that severely affects crop development and yield. Vacuolar detoxification of metal stress is an important strategy for plants to survive and adapt to this adverse environment. Vacuolar iron transporter (VIT members are involved in this process and play essential roles in iron storage and transport. In this study, a rapeseed VIT gene BnMEB2 (BnaC07g30170D was identified. BnMEB2 is a homolog to Arabidopsis MEB2 (At5g24290 and acts as a detoxifier in vacuolar sequestration of divalent metal. Transient expression analysis revealed that BnMEB2 was localized to the vacuolar membrane. Q-PCR detection showed a high expression of BnMEB2 in mature (60-day-old leaves and could be obviously induced by exogenous iron stress in both roots and leaves. Over-expressed BnMEB2 in both Arabidopsis wild type and meb2 mutant seedlings resulted in greatly improved iron tolerability with no significant changes in the expression level of other vacuolar iron transporter genes. The mutant meb2 grew slowly and its root hair elongation was inhibited under high iron concentration condition while BnMEB2 over-expressed transgenic plants of the mutant restored the phenotypes with apparently higher iron storage in roots and dramatically increased iron content in the whole plant. Taken together, these results suggested that BnMEB2 was a VIT gene in rapeseed which was necessary for safe storage and vacuole detoxification function of excess iron to enhance the tolerance of iron toxicity. This research sheds light on a potentially new strategy for attenuating hazardous metal stress from environment and improving iron biofortification in Brassicaceae crops.

  1. Structural and functional diversity of substrate-binding domains in ABC importers

    NARCIS (Netherlands)

    Fulyani, Faizah

    2015-01-01

    In dit proefschrift heb ik de structuur en functie van GlnPQ, een ATP- bindingscassette (ABC) transporter, bepaald. GlnPQ heeft twee verschillende, met elkaar verbonden substraatbindende domeinen (SBDs), die aan het transmembraan domein van de transporter vast zitten. Ondanks het feit dat de

  2. Learning the ABCs: Activity based costing in waste operations

    International Nuclear Information System (INIS)

    Zocher, Marc A.

    1992-01-01

    The United States Department of Energy (DOE) is facing a challenging new national role based on current world events, changing public perception and awareness, and a legacy of wastes generated in the past. Clearly, the DOE must put mechanisms in place to comply with environmental rules, regulations, and good management practices so that public health risk is minimized while programmatic costs are controlled. DOE has begun this process and has developed a Five-Year Plan to describe the activities necessary to comply with both cleanup, or environmental restoration, and waste management of existing waste streams. The focus of this paper is how to best manage the treatment, storage, disposal, and transportation of waste throughout the DOE weapons complex by using Activity Based Costing (ABC) to both plan and control expenditures in DOE Waste Management (WM). The basics of ABC, along with an example, will be detailed. (author)

  3. Assessment of the radiological risks of road transport accidents involving Type A packages

    International Nuclear Information System (INIS)

    Lange, F.; Fett, H.J.; Schwarz, G.; Raffestin, D.; Schneider, T.; Gelder, R.; S. Hughes, J.; B. Shaw, K.; Hedberg, B.; Simenstad, P.; Svahn, B.; Heinen, J.F.A. van; Jansma, R.

    2001-01-01

    An assessment and evaluation of the potential radiological risks of transport accidents involving Type A package shipments by road have been performed by five EU Member States, France, Germany, Sweden, The Netherlands, and the UK. The analysis involved collection and analysis of information on a national basis related to the type, volume, and characteristics of Type A package consignments, the associated radioactive traffic, and the expected frequency and consequences of potential vehicular road transport accidents. It was found that the majority of Type A packaged radioactive material shipments by road is related to applications of non-special form radioactive material, i.e. radiopharmaceuticals, radiochemicals etc., in medicine, research, and industry and special form material contained in radiography and other radiation sources, e.g. gauging equipment. The annual volumes of Type A package shipments of radiopharmaceuticals and radiochemicals by road differ considerably between the participating EU Member States from about 12,000 Type A packages in Sweden to about 240,000 in the Netherlands. The broad range reflects to a large extent the supply of radioactive material for the national populations and the production and distribution operations prevailing in the participating EU Member States (some are producer countries, others are not!). Very few standard package designs weighing from about 1-25 kg are predominant in Type A package shipments in all participating countries. Type A packages contain typically a range of radioactivity from a few mega becquerels to a few tens of giga becquerels, the average package activity contents is in terms of fractions of A 2 about 0.01, i.e. about one hundredth of a Type A package contents limits. Based on a probabilistic risk assessment method it has been concluded that the expected frequencies of occurrence of vehicular road transport accidents with the potential to result in an environmental release - including radiologically

  4. Phase 0 and phase III transport in various organs: combined concept of phases in xenobiotic transport and metabolism.

    Science.gov (United States)

    Döring, Barbara; Petzinger, Ernst

    2014-08-01

    The historical phasing concept of drug metabolism and elimination was introduced to comprise the two phases of metabolism: phase I metabolism for oxidations, reductions and hydrolyses, and phase II metabolism for synthesis. With this concept, biological membrane barriers obstructing the accessibility of metabolism sites in the cells for drugs were not considered. The concept of two phases was extended to a concept of four phases when drug transporters were detected that guided drugs and drug metabolites in and out of the cells. In particular, water soluble or charged drugs are virtually not able to overcome the phospholipid membrane barrier. Drug transporters belong to two main clusters of transporter families: the solute carrier (SLC) families and the ATP binding cassette (ABC) carriers. The ABC transporters comprise seven families with about 20 carriers involved in drug transport. All of them operate as pumps at the expense of ATP splitting. Embedded in the former phase concept, the term "phase III" was introduced by Ishikawa in 1992 for drug export by ABC efflux pumps. SLC comprise 52 families, from which many carriers are drug uptake transporters. Later on, this uptake process was referred to as the "phase 0 transport" of drugs. Transporters for xenobiotics in man and animal are most expressed in liver, but they are also present in extra-hepatic tissues such as in the kidney, the adrenal gland and lung. This review deals with the function of drug carriers in various organs and their impact on drug metabolism and elimination.

  5. Structure and mechanism of ATP-dependent phospholipid transporters

    DEFF Research Database (Denmark)

    Lopez Marques, Rosa Laura; Poulsen, Lisbeth Rosager; Bailly, Aurélien

    2015-01-01

    Background ATP-binding cassette (ABC) transporters and P4-ATPases are two large and seemingly unrelated families of primary active pumps involved in moving phospholipids from one leaflet of a biological membrane to the other. Scope of review This review aims to identify common mechanistic features...... in the way phospholipid flipping is carried out by two evolutionarily unrelated families of transporters. Major conclusions Both protein families hydrolyze ATP, although they employ different mechanisms to use it, and have a comparable size with twelve transmembrane segments in the functional unit. Further......, despite differences in overall architecture, both appear to operate by an alternating access mechanism and during transport they might allow access of phospholipids to the internal part of the transmembrane domain. The latter feature is obvious for ABC transporters, but phospholipids and other hydrophobic...

  6. Playware ABC: Engineering Play for Everybody

    DEFF Research Database (Denmark)

    Lund, Henrik Hautop

    2017-01-01

    This paper describes the Playware ABC concept, and how it allows anybody, anywhere, anytime to be building bodies and brains, which facilitates users to construct, combine and create. The Playware ABC concept focuses engineering and IT system development on creating solutions that are usable by a...

  7. ABC classification : service levels and inventory costs

    NARCIS (Netherlands)

    Teunter, R.H.; Babai, M.; Syntetos, A.

    2010-01-01

    ABC inventory classifications are widely used in practice, with demand value and demand volume as the most common ranking criteria. The standard approach in ABC applications is to set the same service level for all stock keeping units (SKUs) in a class. In this paper, we show (for three large real

  8. Regulatory pathways for ATP-binding cassette transport proteins in kidney proximal tubules.

    Science.gov (United States)

    Masereeuw, Rosalinde; Russel, Frans G M

    2012-12-01

    The ATP-binding cassette transport proteins (ABC transporters) represent important determinants of drug excretion. Protective or excretory tissues where these transporters mediate substrate efflux include the kidney proximal tubule. Regulation of the transport proteins in this tissue requires elaborate signaling pathways, including genetic, epigenetic, nuclear receptor mediated, posttranscriptional gene regulation involving microRNAs, and non-genomic (kinases) pathways triggered by hormones and/or growth factors. This review discusses current knowledge on regulatory pathways for ABC transporters in kidney proximal tubules, with a main focus on P-glycoprotein, multidrug resistance proteins 2 and 4, and breast cancer resistance protein. Insight in these processes is of importance because variations in transporter activity due to certain (disease) conditions could lead to significant changes in drug efficacy or toxicity.

  9. Cellular distribution and function of ion channels involved in transport processes in rat tracheal epithelium.

    Science.gov (United States)

    Hahn, Anne; Faulhaber, Johannes; Srisawang, Lalita; Stortz, Andreas; Salomon, Johanna J; Mall, Marcus A; Frings, Stephan; Möhrlen, Frank

    2017-06-01

    Transport of water and electrolytes in airway epithelia involves chloride-selective ion channels, which are controlled either by cytosolic Ca 2+ or by cAMP The contributions of the two pathways to chloride transport differ among vertebrate species. Because rats are becoming more important as animal model for cystic fibrosis, we have examined how Ca 2+ - dependent and cAMP- dependent Cl - secretion is organized in the rat tracheal epithelium. We examined the expression of the Ca 2+ -gated Cl - channel anoctamin 1 (ANO1), the cystic fibrosis transmembrane conductance regulator (CFTR) Cl - channel, the epithelial Na + channel ENaC, and the water channel aquaporin 5 (AQP5) in rat tracheal epithelium. The contribution of ANO1 channels to nucleotide-stimulated Cl - secretion was determined using the channel blocker Ani9 in short-circuit current recordings obtained from primary cultures of rat tracheal epithelial cells in Ussing chambers. We found that ANO1, CFTR and AQP5 proteins were expressed in nonciliated cells of the tracheal epithelium, whereas ENaC was expressed in ciliated cells. Among nonciliated cells, ANO1 occurred together with CFTR and Muc5b and, in addition, in a different cell type without CFTR and Muc5b. Bioelectrical studies with the ANO1-blocker Ani9 indicated that ANO1 mediated the secretory response to the nucleotide uridine-5'-triphosphate. Our data demonstrate that, in rat tracheal epithelium, Cl - secretion and Na + absorption are routed through different cell types, and that ANO1 channels form the molecular basis of Ca 2+ -dependent Cl - secretion in this tissue. These characteristic features of Cl - -dependent secretion reveal similarities and distinct differences to secretory processes in human airways. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  10. Carrier-Mediated Transport of Nicotine Across the Inner Blood-Retinal Barrier: Involvement of a Novel Organic Cation Transporter Driven by an Outward H(+) Gradient.

    Science.gov (United States)

    Tega, Yuma; Kubo, Yoshiyuki; Yuzurihara, Chihiro; Akanuma, Shin-Ichi; Hosoya, Ken-Ichi

    2015-09-01

    The present study was carried out to investigate the blood-to-retina transport of nicotine across the inner blood-retinal barrier (BRB). Using the in vivo vascular injection method, the blood-to-retina influx clearance of nicotine across the BRB was determined as 131 μL/(min?g retina), which is much higher than that of a nonpermeable paracellular marker, and blood-to-retina transport of nicotine was inhibited by organic cations such as pyrilamine and verapamil. The nicotine uptake by a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2 cells), an in vitro model of the inner BRB, exhibited time, temperature, and concentration dependence with a Km of 492 μM. These results suggest the involvement of a carrier-mediated transport process in nicotine transport in the inner BRB. The nicotine uptake by TR-iBRB2 cells was stimulated by an outwardly directed H(+) gradient, and the uptake was significantly inhibited by bulky and hydrophobic cationic drugs, whereas inhibitors of organic cation transporters did not show inhibitory effect. These results suggest that the novel organic cation transport system driven by an outwardly directed H(+) gradient is involved in the blood-to-retina transport of nicotine across the inner BRB. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  11. ATP-binding cassette (ABC) proteins in aquatic invertebrates: Evolutionary significance and application in marine ecotoxicology.

    Science.gov (United States)

    Jeong, Chang-Bum; Kim, Hui-Su; Kang, Hye-Min; Lee, Jae-Seong

    2017-04-01

    The ATP-binding cassette (ABC) protein superfamily is known to play a fundamental role in biological processes and is highly conserved across animal taxa. The ABC proteins function as active transporters for multiple substrates across the cellular membrane by ATP hydrolysis. As this superfamily is derived from a common ancestor, ABC genes have evolved via lineage-specific duplications through the process of adaptation. In this review, we summarized information about the ABC gene families in aquatic invertebrates, considering their evolution and putative functions in defense mechanisms. Phylogenetic analysis was conducted to examine the evolutionary significance of ABC gene families in aquatic invertebrates. Particularly, a massive expansion of multixenobiotic resistance (MXR)-mediated efflux transporters was identified in the absence of the ABCG2 (BCRP) gene in Ecdysozoa and Platyzoa, suggesting that a loss of Abcg2 gene occurred sporadically in these species during divergence of Protostome to Lophotrochozoa. Furthermore, in aquatic invertebrates, the ecotoxicological significance of MXR is discussed while considering the role of MXR-mediated efflux transporters in response to various environmental pollutants. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Processes and parameters involved in modeling radionuclide transport from bedded salt repositories. Final report. Technical memorandum

    International Nuclear Information System (INIS)

    Evenson, D.E.; Prickett, T.A.; Showalter, P.A.

    1979-07-01

    The parameters necessary to model radionuclide transport in salt beds are identified and described. A proposed plan for disposal of the radioactive wastes generated by nuclear power plants is to store waste canisters in repository sites contained in stable salt formations approximately 600 meters below the ground surface. Among the principal radioactive wastes contained in these canisters will be radioactive isotopes of neptunium, americium, uranium, and plutonium along with many highly radioactive fission products. A concern with this form of waste disposal is the possibility of ground-water flow occurring in the salt beds and endangering water supplies and the public health. Specifically, the research investigated the processes involved in the movement of radioactive wastes from the repository site by groundwater flow. Since the radioactive waste canisters also generate heat, temperature is an important factor. Among the processes affecting movement of radioactive wastes from a repository site in a salt bed are thermal conduction, groundwater movement, ion exchange, radioactive decay, dissolution and precipitation of salt, dispersion and diffusion, adsorption, and thermomigration. In addition, structural changes in the salt beds as a result of temperature changes are important. Based upon the half-lives of the radioactive wastes, he period of concern is on the order of a million years. As a result, major geologic phenomena that could affect both the salt bed and groundwater flow in the salt beds was considered. These phenomena include items such as volcanism, faulting, erosion, glaciation, and the impact of meteorites. CDM reviewed all of the critical processes involved in regional groundwater movement of radioactive wastes and identified and described the parameters that must be included to mathematically model their behavior. In addition, CDM briefly reviewed available echniques to measure these parameters

  13. Efficiency improvement of the investment and innovation activities in the transport facility construction field with public-private partnership involvement

    Science.gov (United States)

    Shibayeva, Marina; Serebryakova, Yelena; Shalnev, Oleg

    2017-10-01

    Growing demand to increase the investment volume in modernization and development projects for transport infrastructure define the urgency of the current study. The amount of private sector investments in the field is insufficient to implement the projects for road construction due to their significant capital intensity and long payoff period. The implementation of social significant infrastructure projects on the principles of public-private partnership is one of the key strategic directions of growth for transport facilities. The authors come up with a concept and methodology for modeling the investment and innovation activity in the transport facility construction. Furthermore, there is developed a model to find the balance between public and private sector investments in implementing construction projects for transport infrastructure with involvement of PPP (further - public-private partnership). The suggested concepts aim to improve the efficiency rate of the investment and innovation activity in the field of transport facility construction on the basis of public and private sectors collaboration.

  14. An ABC for decision making

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Luiz Henrique Costa, E-mail: luiz_mogi@yahoo.com.br [Associacao de Medicina Intensiva Brasileira (AMIB), Sao Paulo, SP (Brazil); Irmandade da Santa Casa de Misericordia de Sao Paulo, SP (Brazil); Ferreira, Bruna Cortez [Hospital de Base de Sao Jose do Rio Preto, SP (Brazil)

    2015-03-15

    The present study was aimed at proposing a systematic evaluation of cranial computed tomography, identifying the main aspects to be analyzed in order to facilitate the decision making process regarding diagnosis and management in emergency settings. The present descriptive study comprised a literature review at the following databases: Access Medicine and Access Emergency Medicine (McGraw-Hill Education); British Medical Journal Evidence Center; UptoDate; Bireme; PubMed; Lilacs; SciELO; ProQuest; Micromedex (Thomson Reuters); Embase. Once the literature review was completed, the authors identified the main diseases with tomographic repercussions and proposed the present system to evaluate cranial computed tomography images. An easy-to-memorize ABC system will facilitate the decision making in emergency settings, as it covers the main diseases encountered by intensivists and emergency physicians, and provides a sequential guidance about anatomical structures to be investigated as well as their respective alterations. (author)

  15. An ABC for decision making

    International Nuclear Information System (INIS)

    Garcia, Luiz Henrique Costa; Ferreira, Bruna Cortez

    2015-01-01

    The present study was aimed at proposing a systematic evaluation of cranial computed tomography, identifying the main aspects to be analyzed in order to facilitate the decision making process regarding diagnosis and management in emergency settings. The present descriptive study comprised a literature review at the following databases: Access Medicine and Access Emergency Medicine (McGraw-Hill Education); British Medical Journal Evidence Center; UptoDate; Bireme; PubMed; Lilacs; SciELO; ProQuest; Micromedex (Thomson Reuters); Embase. Once the literature review was completed, the authors identified the main diseases with tomographic repercussions and proposed the present system to evaluate cranial computed tomography images. An easy-to-memorize ABC system will facilitate the decision making in emergency settings, as it covers the main diseases encountered by intensivists and emergency physicians, and provides a sequential guidance about anatomical structures to be investigated as well as their respective alterations. (author)

  16. An ABC for decision making

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Costa Garcia

    2015-04-01

    Full Text Available The present study was aimed at proposing a systematic evaluation of cranial computed tomography, identifying the main aspects to be analyzed in order to facilitate the decision making process regarding diagnosis and management in emergency settings. The present descriptive study comprised a literature review at the following databases: Access Medicine and Access Emergency Medicine (McGraw- Hill Education; British Medical Journal Evidence Center; UptoDate; Bireme; PubMed; Lilacs; SciELO; ProQuest; Micromedex (Thomson Reuters; Embase. Once the literature review was completed, the authors identified the main diseases with tomographic repercussions and proposed the present system to evaluate cranial computed tomography images. An easy-to-memorize ABC system will facilitate the decision making in emergency settings, as it covers the main diseases encountered by intensivists and emergency physicians, and provides a sequential guidance about anatomical structures to be investigated as well as their respective alterations.

  17. Mechanism(S) Involved in the Colon-Specific Expression of the Thiamine Pyrophosphate (Tpp) Transporter.

    Science.gov (United States)

    Nabokina, Svetlana M; Ramos, Mel Brendan; Said, Hamid M

    2016-01-01

    Microbiota of the large intestine synthesizes considerable amount of vitamin B1 (thiamine) in the form of thiamine pyrophosphate (TPP). We have recently demonstrated the existence of an efficient and specific carrier-mediated uptake process for TPP in human colonocytes, identified the TPP transporter (TPPT) involved (product of the SLC44A4 gene), and shown that expression of TPPT along the gastrointestinal (GI) tract is restricted to the colon. Our aim in this study was to determine the molecular basis of the colon-specific expression of TPPT focusing on a possible epigenetic mechanism. Our results showed that the CpG island predicted in the SLC44A4 promoter is non-methylated in the human colonic epithelial NCM460 cells, but is hyper-methylated in the human duodenal epithelial HuTu80 cells (as well as in the human retinal pigment epithelial ARPE19 cells). In the mouse (where TPPT expression in the GI tract is also restricted to the colon), the CpG island predicted in the Slc44a4 promoter is non-methylated in both the jejunum and colon, thus arguing against possible contribution of DNA methylation in the colon-specific expression of TPPT. A role for histone modifications in the tissue-specific pattern of Slc44a4 expression, however, was suggested by the findings that in mouse colon, histone H3 in the 5'-regulatory region of Slc44a4 is tri-methylated at lysine 4 and acetylated at lysine 9, whereas the tri-methylation at lysine 27 modification was negligible. In contrast, in the mouse jejunum, histone H3 is hyper-trimethylated at lysine 27 (repressor mark). Similarly, possible involvement of miRNA(s) in the tissue-specific expression of TPPT was also suggested by the findings that the 3'-UTR of SLC44A4 is targeted by specific miRNAs/RNA binding proteins in non-colonic, but not in colonic, epithelial cells. These studies show, for the first time, epigenetic mechanisms (histone modifications) play a role in determining the tissue-specific pattern of expression of TPPT

  18. Molecular evidence for an involvement of organic anion transporters (OATs) in aristolochic acid nephropathy

    International Nuclear Information System (INIS)

    Bakhiya, Nadiya; Arlt, Volker M.; Bahn, Andrew; Burckhardt, Gerhard; Phillips, David H.; Glatt, Hansruedi

    2009-01-01

    Aristolochic acid (AA), present in Aristolochia species, is the major causative agent in the development of severe renal failure and urothelial cancers in patients with AA nephropathy. It may also be a cause of Balkan endemic nephropathy. Epithelial cells of the proximal tubule are the primary cellular target of AA. To study whether organic anion transporters (OATs) expressed in proximal tubule cells are involved in uptake of AA, we used human epithelial kidney (HEK293) cells stably expressing human (h) OAT1, OAT3 or OAT4. AA potently inhibited the uptake of characteristic substrates, p-aminohippurate for hOAT1 and estrone sulfate for hOAT3 and hOAT4. Aristolochic acid I (AAI), the more cytotoxic and genotoxic AA congener, exhibited high affinity for hOAT1 (K i = 0.6 μM) as well as hOAT3 (K i = 0.5 μM), and lower affinity for hOAT4 (K i = 20.6 μM). Subsequently, AAI-DNA adduct formation (investigated by 32 P-postlabelling) was used as a measure of AAI uptake. Significantly higher levels of adducts occurred in hOAT-expressing cells than in control cells: this effect was abolished in the presence of the OAT inhibitor probenecid. In Xenopus laevis oocytes hOAT-mediated efflux of p-aminohippurate was trans-stimulated by extracellular AA, providing further molecular evidence for AA translocation by hOATs. Our study indicates that OATs can mediate the uptake of AA into proximal tubule cells and thereby participate in kidney cell damage by this toxin.

  19. Complete inventory of ABC proteins in human pathogenic yeast, Candida albicans.

    Science.gov (United States)

    Gaur, Manisha; Choudhury, Devapriya; Prasad, Rajendra

    2005-01-01

    The recent completion of the sequencing project of the opportunistic human pathogenic yeast, Candida albicans (http://www.ncbi.nlm.nih.gov/), led us to analyze and classify its ATP-binding cassette (ABC) proteins, which constitute one of the largest superfamilies of proteins. Some of its members are multidrug transporters responsible for the commonly encountered problem of antifungal resistance. TBLASTN searches together with domain analysis identified 81 nucleotide-binding domains, which belong to 51 different putative open reading frames. Considering that each allelic pair represents a single ABC protein of the Candida genome, the total number of putative members of this superfamily is 28. Domain organization, sequence-based analysis and self-organizing map-based clustering led to the classification of Candida ABC proteins into 6 distinct subfamilies. Each subfamily from C. albicans has an equivalent in Saccharomyces cerevisiae suggesting a close evolutionary relationship between the two yeasts. Our searches also led to the identification of a new motif to each subfamily in Candida that could be used to identify sequences from the corresponding subfamily in other organisms. It is hoped that the inventory of Candida ABC transporters thus created will provide new insights into the role of ABC proteins in antifungal resistance as well as help in the functional characterization of the superfamily of these proteins. 2005 S. Karger AG, Basel

  20. Podocyte expression of membrane transporters involved in puromycin aminonucleoside-mediated injury.

    Directory of Open Access Journals (Sweden)

    Cristina Zennaro

    Full Text Available Several complex mechanisms contribute to the maintenance of the intricate ramified morphology of glomerular podocytes and to interactions with neighboring cells and the underlying basement membrane. Recently, components of small molecule transporter families have been found in the podocyte membrane, but expression and function of membrane transporters in podocytes is largely unexplored. To investigate this complex field of investigation, we used two molecules which are known substrates of membrane transporters, namely Penicillin G and Puromycin Aminonucleoside (PA. We observed that Penicillin G pre-administration prevented both in vitro and in vivo podocyte damage caused by PA, suggesting the engagement of the same membrane transporters by the two molecules. Indeed, we found that podocytes express a series of transporters which are known to be used by Penicillin G, such as members of the Organic Anion Transporter Polypeptides (OATP/Oatp family of influx transporters, and P-glycoprotein, a member of the MultiDrug Resistance (MDR efflux transporter family. Expression of OATP/Oatp transporters was modified by PA treatment. Similarly, in vitro PA treatment increased mRNA and protein expression of P-glycoprotein, as well as its activity, confirming the engagement of the molecule upon PA administration. In summary, we have characterized some of the small molecule transporters present at the podocyte membrane, focusing on those used by PA to enter and exit the cell. Further investigation will be needed to understand precisely the role of these transporter families in maintaining podocyte homeostasis and in the pathogenesis of podocyte injury.

  1. Zinc Transporter 3 Is Involved in Learned Fear and Extinction, but Not in Innate Fear

    Science.gov (United States)

    Martel, Guillaume; Hevi, Charles; Friebely, Olivia; Baybutt, Trevor; Shumyatsky, Gleb P.

    2010-01-01

    Synaptically released Zn[superscript 2+] is a potential modulator of neurotransmission and synaptic plasticity in fear-conditioning pathways. Zinc transporter 3 (ZnT3) knock-out (KO) mice are well suited to test the role of zinc in learned fear, because ZnT3 is colocalized with synaptic zinc, responsible for its transport to synaptic vesicles,…

  2. ABCs of Oral Health: Nutrition - Children

    Science.gov (United States)

    ... higher risk for heart attacks More ABCs of Oral Health A | B | C | D | E | F | G | H | ... Children Home | InfoBites | Find a Dentist | Your Family's Oral Health | RSS About AGD | Contact AGD | Site Map | Reprints ...

  3. ABC Inventory classification application: Özdemirler

    OpenAIRE

    Duru, Mehmet

    1989-01-01

    Ankara : The Department of Management and the Institute of Management Sciences of Bilkent Univ. , 1989. Thesis (Master's) -- Bilkent University, 1989. Includes bibliographical references leaves 37. ABC inventory classification can result in more effective control of business. In this work, ABC method is applied to Ozdemirler to examine the inventory profile of the store, and to be able to aid the management in allocating control effort among items more effectively. Dur...

  4. Involvement of Carrier-Mediated Transport at the Blood-Cerebrospinal Fluid Barrier in Spermine Clearance from Rat Brain.

    Science.gov (United States)

    Akanuma, Shin-Ichi; Shimada, Hirokazu; Kubo, Yoshiyuki; Hosoya, Ken-Ichi

    2017-01-01

    Spermine is the end-product in the polyamine biosynthetic pathway, and its excess accumulation induces neuroexcitatory responses and neurotoxicity. The purpose of this study was to elucidate the involvement of transport systems at the brain barriers in the clearance of spermine. In vivo rat spermine elimination from brain parenchyma across the blood-brain barrier (BBB) and blood-cerebrospinal fluid (CSF) barrier (BCSFB) was assessed by intracerebral and intracerebroventricular administration techniques, respectively. To characterize spermine transport at the BCSFB, a transport study using rat choroid plexus was performed. After the intracerebral microinjection of [ 3 H]spermine, no time-dependent decrease in [ 3 H]spermine in the ipsilateral cerebrum was observed, suggesting the low contribution of the BBB to spermine clearance from the brain. In contrast, the [ 3 H]spermine concentration in the CSF after intracerebroventricular administration was time-dependently decreased with an elimination rate constant of 0.352 min -1 , and the elimination clearance of [ 3 H]spermine was 6.6-fold greater than that of [ 14 C]D-mannitol, reflecting bulk flow of the CSF. This [ 3 H]spermine elimination was attenuated by co-administration of unlabeled excess spermine, indicating carrier-mediated elimination of spermine from the CSF. [ 3 H]Spermine transport into the choroid plexus was strongly inhibited by unlabeled spermine, other polyamines (spermidine and putrescine), and organic cation transporter substrates such as corticosterone and 1-methyl-4-phenylpyridinium. However, other substrates/inhibitors for organic cation transporters (decynium-22 and tetraethylammonium) had little effect. Consequently, our study indicates that transporting molecules at the BCSFB, distinct from typical organic cation transporters, are involved in spermine clearance from the CSF.

  5. AaPDR3, a PDR Transporter 3, Is Involved in Sesquiterpene β-Caryophyllene Transport in Artemisia annua

    Science.gov (United States)

    Fu, Xueqing; Shi, Pu; He, Qian; Shen, Qian; Tang, Yueli; Pan, Qifang; Ma, Yanan; Yan, Tingxiang; Chen, Minghui; Hao, Xiaolong; Liu, Pin; Li, Ling; Wang, Yuliang; Sun, Xiaofen; Tang, Kexuan

    2017-01-01

    Artemisinin, a sesquiterpenoid endoperoxide, isolated from the plant Artemisia annua L., is widely used in the treatment of malaria. Another sesquiterpenoid, β-caryophyllene having antibiotic, antioxidant, anticarcinogenic and local anesthetic activities, is also presented in A. annua. The role played by sesquiterpene transporters in trichomes and accumulation of these metabolites is poorly understood in A. annua and in trichomes of other plant species. We identified AaPDR3, encoding a pleiotropic drug resistance (PDR) transporter located to the plasma membrane from A. annua. Expression of AaPDR3 is tissue-specifically and developmentally regulated in A. annua. GUS activity is primarily restricted to T-shaped trichomes of old leaves and roots of transgenic A. annua plants expressing proAaPDR3: GUS. The level of β-caryophyllene was decreased in transgenic A. annua plants expressing AaPDR3-RNAi while transgenic A. annua plants expressing increased levels of AaPDR3 accumulated higher levels of β-caryophyllene. When AaPDR3 was expressed in transformed yeast, yeasts expressing AaPDR3 accumulated more β-caryophyllene, rather than germacrene D and β-farnesene, compared to the non-expressing control. PMID:28533790

  6. Marketing Research of Construction Sites based on ABC-XYZ Analysis and Relational Data

    Directory of Open Access Journals (Sweden)

    Konikov Aleksandr

    2017-01-01

    Full Text Available ABC-XYZ analysis is well known in marketing. It allows identifying sites that yield maximum profits when sold, sites that enjoy stable demand, or sites have both qualities specified above. However, the methods are quite abstract and are not designed to study specific factors that impact the results of ABC-XYZ analysis. Meanwhile, for some applications, particularly for marketing research of construction sites, it is critical not only to identify high-profit and stable sites but also to find out what combination of technical parameters, factors related to their location, transport accessibility, etc. are typical of them. This work suggests an approach to address the issue.

  7. A kinome wide screen identifies novel kinases involved in regulation of monoamine transporter function

    DEFF Research Database (Denmark)

    Vuorenpää, Anne Elina; Ammendrup-Johnsen, Ina; Jorgensen, Trine N.

    2016-01-01

    cells (CAD) and rat chromocytoma (PC12) cells. Whereas SIK3 likely transcriptionally regulated expression of the three transfected transporters, depletion of PKA C-α was shown to decrease SERT function. Depletion of PrKX caused decreased surface expression and function of DAT without changing protein...... in regulation of monoamine transporter function and surface expression. A primary screen in HEK 293 cells stably expressing DAT or SERT with siRNAs against 573 human kinases revealed 93 kinases putatively regulating transporter function. All 93 hits, which also included kinases previously implicated...... in HEK 293 cells transiently expressing DAT, SERT or NET. Subsequently, three kinases; salt inducible kinase 3 (SIK3), cAMP-dependent protein kinase catalytic subunit alpha (PKA C-α) and protein kinase X-linked (PrKX); were selected for additional exploration in catecholaminergic CATH.a differentiated...

  8. Early-Onset Alzheimer Disease and Candidate Risk Genes Involved in Endolysosomal Transport.

    Science.gov (United States)

    Kunkle, Brian W; Vardarajan, Badri N; Naj, Adam C; Whitehead, Patrice L; Rolati, Sophie; Slifer, Susan; Carney, Regina M; Cuccaro, Michael L; Vance, Jeffery M; Gilbert, John R; Wang, Li-San; Farrer, Lindsay A; Reitz, Christiane; Haines, Jonathan L; Beecham, Gary W; Martin, Eden R; Schellenberg, Gerard D; Mayeux, Richard P; Pericak-Vance, Margaret A

    2017-09-01

    gene RIN3 showed suggestive evidence of association with EOAD after Bonferroni correction (OR, 4.56; 95% CI, 1.26-16.48; P = .02, BP = 0.091). In addition, a missense variant in RUFY1 identified in 2 NHW EOAD cases showed suggestive evidence of an association with EOAD as well (OR, 18.63; 95% CI, 1.62-213.45; P = .003; BP = 0.129). The genes PSD2, TCIRG1, RIN3, and RUFY1 all may be involved in endolysosomal transport-a process known to be important to development of AD. Furthermore, this study identified shared risk genes between EOAD and LOAD similar to previously reported genes, such as SORL1, PSEN2, and TREM2.

  9. Acropetal Auxin Transport Inhibition Is Involved in Indeterminate But Not Determinate Nodule Formation

    Directory of Open Access Journals (Sweden)

    Jason L. P. Ng

    2018-02-01

    Full Text Available Legumes enter into a symbiotic relationship with nitrogen-fixing rhizobia, leading to nodule development. Two main types of nodules have been widely studied, indeterminate and determinate, which differ in the location of the first cell division in the root cortex, and persistency of the nodule meristem. Here, we compared the control of auxin transport, content, and response during the early stages of indeterminate and determinate nodule development in the model legumes Medicago truncatula and Lotus japonicus, respectively, to investigate whether differences in auxin transport control could explain the differences in the location of cortical cell divisions. While auxin responses were activated in dividing cortical cells during nodulation of both nodule types, auxin (indole-3-acetic acid content at the nodule initiation site was transiently increased in M. truncatula, but transiently reduced in L. japonicus. Root acropetal auxin transport was reduced in M. truncatula at the very start of nodule initiation, in contrast to a prolonged increase in acropetal auxin transport in L. japonicus. The auxin transport inhibitors 2,3,5-triiodobenzoic acid and 1-N-naphthylphthalamic acid (NPA only induced pseudonodules in legume species forming indeterminate nodules, but failed to elicit such structures in a range of species forming determinate nodules. The development of these pseudonodules in M. truncatula exhibited increased auxin responses in a small primordium formed from the pericycle, endodermis, and inner cortex, similar to rhizobia-induced nodule primordia. In contrast, a diffuse cortical auxin response and no associated cortical cell divisions were found in L. japonicus. Collectively, we hypothesize that a step of acropetal auxin transport inhibition is unique to the process of indeterminate nodule development, leading to auxin responses in pericycle, endodermis, and inner cortex cells, while increased auxin responses in outer cortex cells likely

  10. Parental Involvement in Active Transport to School Initiatives: A Multi-Site Case Study

    Science.gov (United States)

    Eyler, Amy; Baldwin, Julie; Carnoske, Cheryl; Nickelson, Jan; Troped, Philip; Steinman, Lesley; Pluto, Delores; Litt, Jill; Evenson, Kelly; Terpstra, Jennifer; Brownson, Ross; Schmid, Thomas

    2008-01-01

    Background: Increasing physical activity in youth is a recommended approach to curbing the childhood obesity epidemic. One way to help increase children's daily activity is to promote active transportation to and from school (ATS). Purpose: The purpose of this case study was to explore parental perception of, and participation in, ATS initiatives.…

  11. Involvement of organic cation transporter 1 in the lactic acidosis caused bv metformin

    NARCIS (Netherlands)

    Wang, DS; Kusuhara, H; Kato, Y; Jonker, JW; Schinkel, AH; Sugiyama, Y

    Biguanides are a class of drugs widely used as oral antihyperglycemic agents for the treatment of type 2 diabetes mellitus, but they are associated with lactic acidosis, a lethal side effect. We reported previously that biguanides are good substrates of rat organic cation transporter 1 (Oct1;

  12. Organelles involved in the intracellular transport of newly synthesized aminopeptidase N and their acidity

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Danielsen, E M; Sjöström, H

    1989-01-01

    vesicles are exocytotic and that the low pH in the acid compartments is of no importance for intracellular transport and correct sorting of aminopeptidase N. Furthermore, our results show that the majority of the aminopeptidase N in the lysosomal/endosomal-like compartments is newly synthesized....

  13. Bile secretion of cadmium, silver, zinc and copper in the rat. Involvement of various transport systems.

    NARCIS (Netherlands)

    Havinga, R; Vonk, RJ; Kuipers, F

    1996-01-01

    In the present study we compared, in vivo in rats, the hepatobiliary transport of monovalent (silver:Ag) and divalent metals (zinc:Zn; cadmium:Cd) with that of copper (Cu). Cu can have two oxidation states in vivo, i.e. Cu(I) and Cu(II). Studies were performed in normal Wistar (NW) rats and mutant

  14. Atomic force microscopy analysis of SasA-KaiC complex formation involved in information transfer from the KaiABC clock machinery to the output pathway in cyanobacteria.

    Science.gov (United States)

    Murakami, Reiko; Hokonohara, Hitomi; Che, Dock-Chil; Kawai, Tomoji; Matsumoto, Takuya; Ishiura, Masahiro

    2018-03-12

    The cyanobacterial clock oscillator is composed of three clock proteins: KaiA, KaiB and KaiC. SasA, a KaiC-binding EnvZ-like orthodox histidine kinase involved in the main clock output pathway, exists mainly as a trimer (SasA 3mer ) and occasionally as a hexamer (SasA 6mer ) in vitro. Previously, the molecular mass of the SasA-KaiC DD complex, where KaiC DD is a mutant KaiC with two Asp substitutions at the two phosphorylation sites, has been estimated by gel-filtration chromatography to be larger than 670 kDa. This value disagrees with the theoretical estimation of 480 kDa for a SasA 3mer -KaiC hexamer (KaiC 6mer ) complex with a 1:1 molecular ratio. To clarify the structure of the SasA-KaiC complex, we analyzed KaiC DD with 0.1 mmol/L ATP and 5 mmol/L MgCl 2 (Mg-ATP), SasA and a mixture containing SasA and KaiC DD 6mer with Mg-ATP by atomic force microscopy (AFM). KaiC DD images were classified into two types with height distribution corresponding to KaiC DD monomer (KaiC DD 1mer ) and KaiC DD 6mer , respectively. SasA images were classified into two types with height corresponding to SasA 3mer and SasA 6mer , respectively. The AFM images of the SasA-KaiC DD mixture indicated not only KaiC DD 1mer , KaiC DD 6mer , SasA 3mer and SasA 6mer , but also wider area "islands," suggesting the presence of a polymerized form of the SasA-KaiC DD complex. © 2018 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  15. Transport company safety climate-The impact on truck driver behavior and crash involvement.

    Science.gov (United States)

    Sullman, Mark J M; Stephens, Amanda N; Pajo, Karl

    2017-04-03

    The present study investigated the relationships between safety climate and driving behavior and crash involvement. A total of 339 company-employed truck drivers completed a questionnaire that measured their perceptions of safety climate, crash record, speed choice, and aberrant driving behaviors (errors, lapses, and violations). Although there was no direct relationship between the drivers' perceptions of safety climate and crash involvement, safety climate was a significant predictor of engagement in risky driving behaviors, which were in turn predictive of crash involvement. This research shows that safety climate may offer an important starting point for interventions aimed at reducing risky driving behavior and thus fewer vehicle collisions.

  16. Transcorneal permeation of L- and D-aspartate ester prodrugs of acyclovir: delineation of passive diffusion versus transporter involvement.

    Science.gov (United States)

    Majumdar, Soumyajit; Hingorani, Tushar; Srirangam, Ramesh; Gadepalli, Rama Sarma; Rimoldi, John M; Repka, Michael A

    2009-05-01

    The aim of this study was to evaluate the contribution of amino acid transporters in the transcorneal permeation of the aspartate (Asp) ester acyclovir (ACV) prodrug. Physicochemical characterization, solubility and stability of acyclovir L-aspartate (L-Asp-ACV) and acyclovir D-aspartate (D-Asp-ACV) were studied. Transcorneal permeability was evaluated across excised rabbit cornea. Solubility of L-Asp-ACV and D-Asp-ACV were about twofold higher than that of ACV. The prodrugs demonstrated greater stability under acidic conditions. Calculated pK(a) and logP values for both prodrugs were identical. Transcorneal permeability of L-Asp-ACV (12.1 +/- 1.48 x 10(-6) cm/s) was fourfold higher than D-Asp-ACV (3.12 +/- 0.36 x 10(-6) cm/s) and ACV (3.25 +/- 0.56 x 10(-6) cm/s). ACV generation during the transport process was minimal. L-Asp-ACV transport was sodium and energy dependent but was not inhibited by glutamic acid. Addition of BCH, a specific B(0,+) and L amino acid transporter inhibitor, decreased transcorneal L-Asp-ACV permeability to 2.66 +/- 0.21 x 10(-6) cm/s. L-Asp-ACV and D-Asp-ACV did not demonstrate significant difference in stability in ocular tissue homogenates. The results demonstrate that enhanced transport of L-Asp-ACV is as a result of corneal transporter involvement (probably amino acid transporter B(0,+)) and not as a result of changes in physicochemical properties due to prodrug derivatization (permeability of D-Asp-ACV and ACV were not significantly different).

  17. Protective Behaviour of Citizens to Transport Accidents Involving Hazardous Materials: A Discrete Choice Experiment Applied to Populated Areas nearby Waterways.

    Science.gov (United States)

    de Bekker-Grob, Esther W; Bergstra, Arnold D; Bliemer, Michiel C J; Trijssenaar-Buhre, Inge J M; Burdorf, Alex

    2015-01-01

    To improve the information for and preparation of citizens at risk to hazardous material transport accidents, a first important step is to determine how different characteristics of hazardous material transport accidents will influence citizens' protective behaviour. However, quantitative studies investigating citizens' protective behaviour in case of hazardous material transport accidents are scarce. A discrete choice experiment was conducted among subjects (19-64 years) living in the direct vicinity of a large waterway. Scenarios were described by three transport accident characteristics: odour perception, smoke/vapour perception, and the proportion of people in the environment that were leaving at their own discretion. Subjects were asked to consider each scenario as realistic and to choose the alternative that was most appealing to them: staying, seeking shelter, or escaping. A panel error component model was used to quantify how different transport accident characteristics influenced subjects' protective behaviour. The response was 44% (881/1,994). The predicted probability that a subject would stay ranged from 1% in case of a severe looking accident till 62% in case of a mild looking accident. All three transport accident characteristics proved to influence protective behaviour. Particularly a perception of strong ammonia or mercaptan odours and visible smoke/vapour close to citizens had the strongest positive influence on escaping. In general, 'escaping' was more preferred than 'seeking shelter', although stated preference heterogeneity among subjects for these protective behaviour options was substantial. Males were less willing to seek shelter than females, whereas elderly people were more willing to escape than younger people. Various characteristics of transport accident involving hazardous materials influence subjects' protective behaviour. The preference heterogeneity shows that information needs to be targeted differently depending on gender and age

  18. Environmental health, public safety, and social impacts associated with transportation accidents involving hazardous substances

    Science.gov (United States)

    2000-12-31

    Accidents involving chemicals or radioactive materials represent a significant threat to the environment, public : health and safety, and community well-being. In an increasingly complex and interconnected world, no community : is immune from the thr...

  19. Assessment of the radiological risks of road transport accidents involving type A-packages

    International Nuclear Information System (INIS)

    Lange, F.; Fett, H.J.; Schwarz, G.; Raffestin, D.; Schneider, T.; Gelder, R.; Hughes, J.S.; Shaw, K.B.; Hedberg, B.; Simenstad, P.; Svahn, B.; Van Hienen, J.F.A.; Jansma, R.

    1998-10-01

    This document, prepared in the framework of a study for the European Commission, presents the evaluation of the risks of accidents associated to the road transport of type A-packages (primarily packages of radio-pharmaceutic or radiography products) for five countries of the European Union. The annual transport of type A-packages varies considerably from one country to another, some countries being producers of radio-pharmaceutic products, others not. These packages are also very different one from each another: the weight varies generally from 1 to 25 kg and the activity from some Mega-Becquerels to few tens of Giga-Becquerels, the average activity expressed in A 2 is 0,01. (A.L.B.)

  20. Involving Freight Transport Actors in Production of Knowledge - Experience with Future Workshop Methodology

    DEFF Research Database (Denmark)

    Jespersen, Per Homann; Drewes, Lise

    2005-01-01

    . The validation of the research is taken ex post when the results are presented in reports for discussions in public. The effect of the research on practice is seldom evaluated. The research presented in this paper has a quite different aim. Taking our inspiration from modern action research, we have......The freight transport sector plays a major role in the process of globalisation and accounts for a large and increasing share of the economy and workforce. This growth in turn results in a range of societal problems – externally as environmental and health problems, internally as a number...... of congestion problems. In spite of this, freight transport has been somewhat neglected in qualitative oriented social sciences such as sociology and socio-economy, and thus a lack of analytical understanding as well as problem solving competences prevail. This chapter presents a methodology where...

  1. A New Metal Binding Domain Involved in Cadmium, Cobalt and Zinc Transport

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Aaron T. [Northwestern Univ., Evanston, IL (United States); Barupala, Dulmini [Wayne State Univ., Detroit, MI (United States); Stemmler, Timothy L. [Wayne State Univ., Detroit, MI (United States); Rosenzweig, Amy C. [Northwestern Univ., Evanston, IL (United States)

    2015-07-20

    In the P1B-ATPases, which couple cation transport across membranes to ATP hydrolysis, are central to metal homeostasis in all organisms. An important feature of P1B-ATPases is the presence of soluble metal binding domains (MBDs) that regulate transport activity. Only one type of MBD has been characterized extensively, but bioinformatics analyses indicate that a diversity of MBDs may exist in nature. Here we report the biochemical, structural and functional characterization of a new MBD from the Cupriavidus metallidurans P1B-4-ATPase CzcP (CzcP MBD). The CzcP MBD binds two Cd2+, Co2+ or Zn2+ ions in distinct and unique sites and adopts an unexpected fold consisting of two fused ferredoxin-like domains. Both in vitro and in vivo activity assays using full-length CzcP, truncated CzcP and several variants indicate a regulatory role for the MBD and distinct functions for the two metal binding sites. Moreover, these findings elucidate a previously unknown MBD and suggest new regulatory mechanisms for metal transport by P1B-ATPases.

  2. Involvement of FST1 from Fusarium verticillioides in virulence and transport of inositol.

    Science.gov (United States)

    Niu, Chenxing; Payne, Gary A; Woloshuk, Charles P

    2017-06-01

    Fumonisin B1 (FB1), a polyketide mycotoxin produced by Fusarium verticillioides during the colonization of maize kernels, is detrimental to human and animal health. FST1 encodes a putative protein with 12 transmembrane domains; however, its function remains unknown. The FST1 gene is highly expressed by the fungus in the endosperm of maize kernels compared with the levels of expression in germ tissues. Previous research has shown that FST1 affects FB1 production, virulence, hydrogen peroxide resistance, hydrophobicity and macroconidia production. Here, we examine the phylogeny of FST1, its expression in a Saccharomyces cerevisiae strain lacking a functional myo-inositol transporter (ITR1) and the effect of amino acid changes in the central loop and C-terminus regions of FST1 on functionality. The results indicate that expression of FST1 in an ITR1 mutant strain restores growth on myo-inositol medium to wild-type levels and restores the inhibitory effects of FB1, suggesting that FST1 can transport both myo-inositol and FB1 into yeast cells. Our results with engineered FST1 also indicate that amino acids in the central loop and C-terminus regions are important for FST1 functionality in both S. cerevisiae and F. verticillioides. Overall, this research has established the first characterized inositol transporter in filamentous fungi and has advanced our knowledge about the global regulatory functions of FST1. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  3. abc: An extensible AspectJ compiler

    DEFF Research Database (Denmark)

    Avgustinov, Pavel; Christensen, Aske Simon; Hendren, Laurie

    2005-01-01

    Research in the design of aspect-oriented programming languages requires a workbench that facilitates easy experimentation with new language features and implementation techniques. In particular, new features for AspectJ have been proposed that require extensions in many dimensions: syntax, type...... checking and code generation, as well as data flow and control flow analyses. The AspectBench Compiler (abc) is an implementation of such a workbench. The base version of abc implements the full AspectJ language. Its frontend is built, using the Polyglot framework, as a modular extension of the Java...... language. The use of Polyglot gives flexibility of syntax and type checking. The backend is built using the Soot framework, to give modular code generation and analyses. In this paper, we outline the design of abc, focusing mostly on how the design supports extensibility. We then provide a general overview...

  4. An Electrically Tight In Vitro Blood-Brain Barrier Model Displays Net Brain-to-Blood Efflux of Substrates for the ABC Transporters, P-gp, Bcrp and Mrp-1

    DEFF Research Database (Denmark)

    Helms, Hans Christian; Hersom, Maria; Kuhlmann, Louise Borella

    2014-01-01

    if a bovine endothelial/rat astrocyte in vitro BBB co-culture model displayed polarized transport of known efflux transporter substrates. The co-culture model displayed low mannitol permeabilities of 0.95 ± 0.1 · 10(-6) cm·s(-1) and high transendothelial electrical resistances of 1,177 ± 101 Ω·cm(2...

  5. Regional differences in glutathione accumulation pathways in the rat cornea: Mapping of amino acid transporters involved in glutathione synthesis.

    Science.gov (United States)

    Yoganandarajah, Vithushiya; Li, Bo; Umapathy, Ankita; Donaldson, Paul J; Lim, Julie C

    2017-08-01

    In this study we have sought to complete the identification and localisation of uptake pathways involved in accumulating precursor amino acids involved in GSH synthesis in the rat cornea. To do this, we performed reverse transcription PCR (RT-PCR) to identify the Excitatory Amino Acid Transporters (EAAT 1-5) responsible for glutamate uptake, and glycine transporters (GLYT 1-2) at the transcript level. Western blotting was used to verify protein expression, while immunolabelling of sagittal sections was used to localise transporters to the different layers of the cornea. Immunolabelling of en face sections was used to examine the subcellular distribution of proteins in the corneal endothelium. Our findings revealed EAAT 1-5 and GLYT 1-2 to be expressed at the transcript and protein level in the rat cornea. Immunohistochemistry revealed all amino acid transporters to be localised to the epithelium. In the majority of cases, labelling was restricted to the epithelium, and labelling absent from the stroma or endothelium. However, EAAT 4 and GLYT 2 labelling was detected in the stroma with EAAT 4 labelling also present in the endothelium. Overall, the identification of amino acid transporters strongly supports the existence of an intracellular GSH synthesis pathway in the rat corneal epithelium. This suggests that regional differences in GSH accumulation pathways exist, with direct uptake of GSH and intracellular synthesis of GSH restricted to the endothelial and epithelial cell layers, respectively. This information is important in the design of targeted strategies to enhance GSH levels in specific layers of the cornea to prevent against oxidative damage, corneal swelling and loss of corneal transparency. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Analysis of behavioral intention on ABC system adoption: Model of information systems technology and success acceptance

    Directory of Open Access Journals (Sweden)

    Baiq Nensi Veni Indipenrian

    2015-12-01

    Full Text Available This study aims to examine the effect of individual behavioral change on the adoption of activity- based costing (ABC system and its usage, using Unified Theory of Accep-tance and Use of Technology (UTAUT and Information System Success Model. The sample involves 78 respondents who have positions as financial manager, controller manager, accounting manager, and production manager in mid-sized manufacturing companies in East java. The data were collected by survey method. This study used a Partial Least Square (PLS as the data analysis method. It was found that not all of the main UTAUT models were supported, because performance expectancy and effort expectancy have no effect on behavioral intention and use behavior to adopt ABC system. Whereas, social factors, information quality and facilitating conditions had a positive effect on behavioral intention and use behavior to adopt ABC system. The different results of this study with several previous studies are probably caused by the differences in the context of system, culture and characteristics of the sample. The implication of this study is not only to propose a theoretical framework for researches in future, but also useful for companies to optimize the use of ABC system that should be supported by top level and mid-level management and the readiness of the individu-als to accept the adoption of the ABC system.

  7. ABC model and the management of costs

    Directory of Open Access Journals (Sweden)

    Pravdić Predrag

    2016-01-01

    Full Text Available When a company has multiple objectives at the same time, they all must be considered and balanced when making any business decisions. Linking the markets, capital and resources so as to thus ensure the highest yield is, In fact, the search for competitive advantage as a basic condition for survival in a market economy. In highly detailed systems based on the management of costs or ABC (activity based costing systems, the cost of activities often result in erroneous evaluation of aggregate costs of the action. Improvements in information technology and monitoring decrease of technology costs enabled the ABC system to become a feasible system calculating costs in many organizations.

  8. Expression and functional studies of genes involved in transport and metabolism of glycerol in Pachysolen tannophilus

    DEFF Research Database (Denmark)

    Liu, Xiaoying; Mortensen, Uffe Hasbro; Workman, Mhairi

    2013-01-01

    P. tannophilus has characteristics relevant for a microbial cell factory to be applied in a biorefinery setting, i.e. its ability to utilise the carbon sources such as xylose and glycerol. However, the strain is not currently amenable to genetic modification and transformation. Heterologous...... expression of the glycerol transporters from P. tannophilus, which has a relatively high growth rate on glycerol, could be used as an approach for improving the efficiency of glycerol assimilation in other well characterized and applied cell factories such as S. cerevisiae....

  9. Heat shock protein 27-derived atheroprotection involves reverse cholesterol transport that is dependent on GM-CSF to maintain ABCA1 and ABCG1 expression in ApoE-/- mice.

    Science.gov (United States)

    Pulakazhi Venu, Vivek Krishna; Adijiang, Ayinuer; Seibert, Tara; Chen, Yong-Xiang; Shi, Chunhua; Batulan, Zarah; O'Brien, Edward R

    2017-06-01

    Recently, we demonstrated that heat shock protein (HSP)-27 is protective against the development of experimental atherosclerosis, reducing plaque cholesterol content by more than 30%. Moreover, elevated HSP-27 levels are predictive of relative freedom from clinical cardiovascular events. HSP-27 signaling occurs via the activation of NF-κB, which induces a marked up-regulation in expression of granulocyte-monocyte colony-stimulating factor (GM-CSF), a cytokine that is known to alter ABC transporters involved in reverse cholesterol transport (RCT). Therefore, we hypothesized that HSP-27-derived GM-CSF has a potent role in impeding plaque formation by promoting macrophage RCT and sought to better characterize this pathway. Treatment of THP-1 cells, RAW-Blue cells, and primary macrophages with recombinant HSP-27 resulted in NF-κB activation via TLR-4 and was inhibited by various pharmacologic blockers of this pathway. Moreover, HSP-27-induced upregulation of GM-CSF expression was dependent on TLR-4 signaling. Recombinant (r)HSP-27 treatment of ApoE -/- female (but not male) mice for 4 wk yielded reductions in plaque area and cholesterol clefts of 33 and 47%, respectively, with no effect on GM-CSF -/- ApoE -/- mice. With 12 wk of rHSP-27 treatment, both female and male mice showed reductions in plaque burden (55 and 42%, respectively) and a 60% reduction in necrotic core area but no treatment effect in GM-CSF -/- ApoE -/- mice. In vitro functional studies revealed that HSP-27 enhanced the expression of ABCA1 and ABCG1, as well as facilitated cholesterol efflux in vitro by ∼10%. These novel findings establish a paradigm for HSP-27-mediated RCT and set the stage for the development of HSP-27 atheroprotective therapeutics.-Pulakazhi Venu, V. K., Adijiang, A., Seibert, T., Chen, Y.-X., Shi, C., Batulan, Z., O'Brien, E. R. Heat shock protein 27-derived atheroprotection involves reverse cholesterol transport that is dependent on GM-CSF to maintain ABCA1 and ABCG1

  10. Multi-choice stochastic transportation problem involving general form of distributions.

    Science.gov (United States)

    Quddoos, Abdul; Ull Hasan, Md Gulzar; Khalid, Mohammad Masood

    2014-01-01

    Many authors have presented studies of multi-choice stochastic transportation problem (MCSTP) where availability and demand parameters follow a particular probability distribution (such as exponential, weibull, cauchy or extreme value). In this paper an MCSTP is considered where availability and demand parameters follow general form of distribution and a generalized equivalent deterministic model (GMCSTP) of MCSTP is obtained. It is also shown that all previous models obtained by different authors can be deduced with the help of GMCSTP. MCSTP with pareto, power function or burr-XII distributions are also considered and equivalent deterministic models are obtained. To illustrate the proposed model two numerical examples are presented and solved using LINGO 13.0 software package.

  11. Retinoblastoma-binding Protein 4-regulated Classical Nuclear Transport Is Involved in Cellular Senescence*

    Science.gov (United States)

    Tsujii, Akira; Miyamoto, Yoichi; Moriyama, Tetsuji; Tsuchiya, Yuko; Obuse, Chikashi; Mizuguchi, Kenji; Oka, Masahiro; Yoneda, Yoshihiro

    2015-01-01

    Nucleocytoplasmic trafficking is a fundamental cellular process in eukaryotic cells. Here, we demonstrated that retinoblastoma-binding protein 4 (RBBP4) functions as a novel regulatory factor to increase the efficiency of importin α/β-mediated nuclear import. RBBP4 accelerates the release of importin β1 from importin α via competitive binding to the importin β-binding domain of importin α in the presence of RanGTP. Therefore, it facilitates importin α/β-mediated nuclear import. We showed that the importin α/β pathway is down-regulated in replicative senescent cells, concomitant with a decrease in RBBP4 level. Knockdown of RBBP4 caused both suppression of nuclear transport and induction of cellular senescence. This is the first report to identify a factor that competes with importin β1 to bind to importin α, and it demonstrates that the loss of this factor can trigger cellular senescence. PMID:26491019

  12. Wallerian degeneration slow mouse neurons are protected against cell death caused by mechanisms involving mitochondrial electron transport dysfunction.

    Science.gov (United States)

    Tokunaga, Shinji; Araki, Toshiyuki

    2012-03-01

    Ischemia elicits a variety of stress responses in neuronal cells, which result in cell death. wld(S) Mice bear a mutation that significantly delays Wallerian degeneration. This mutation also protects all neuronal cells against other types of stresses resulting in cell death, including ischemia. To clarify the types of stresses that neuronal cell bodies derived from wld(S) mice are protected from, we exposed primary cultured neurons derived from wld(S) mice to various components of hypoxic stress. We found that wld(S) mouse neurons are protected against cellular injury induced by reoxygenation following hypoxic stress. Furthermore, we found that wld(S) mouse neurons are protected against functional impairment of the mitochondrial electron transport chain. These data suggest that Wld(S) protein expression may provide protection against neuronal cell death caused by mechanisms involving mitochondrial electron transport dysfunction. Copyright © 2011 Wiley Periodicals, Inc.

  13. The ABC-paradox: is Time Driven ABC relevant for small and Medium sized enterprises (SME)?

    DEFF Research Database (Denmark)

    Fladkjær, Henrik Find; Jensen, Erling

    -books and in curriculum at most business schools. But ABC is not used very much by the compa-nies. Especially in small and medium enterprises ABC is rarely implemented. This is primarily due to two things: First, the ABC model is too difficult to implement. Second, the data foundation for the model is not available...... in the required quality in the ERP systems used by the businesses. In this article we will explore ways of overcoming these two related problems. We will explore these issues particularly in relation to small and medium enterprises. Through a theoretical analysis and practical implementation in a medium sized...... manufacturing company we will analyse whether it is possible to create a satisfactory decision making foundation using a TDABC as a less complex cost model in the company. We have analysed our way to the conclusion that compared to ABC, the TDABC model provides the management with a number of pragmatic...

  14. Step 2: Know Your Diabetes ABCs

    Science.gov (United States)

    ... page please turn JavaScript on. Feature: Type 2 Diabetes Step 2: Know Your Diabetes ABCs Past Issues / Fall 2014 Table of Contents ... cholesterol helps remove cholesterol from your blood vessels. Diabetes HealthSense Find tools and programs that can help ...

  15. ABC – Advocates for Breast Cancer

    African Journals Online (AJOL)

    Cancer 2008;113(S8):221-224. [http://dx.doi.org/10.1002/cncr.23844]. ARTICLE. ABC – Advocates for Breast Cancer. A Steyn,1 Dip DA (Lond), LRAM (Speech and Drama) (Lond); J du Plessis;2 S Meyer,3 MSocSc (SW). 1 Immediate Past President, Reach to Recovery International, Queensland, Australia. 2 Chief Executive ...

  16. Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120

    Directory of Open Access Journals (Sweden)

    Rafael Pernil

    2015-04-01

    Full Text Available Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion.

  17. Modelling of the blood-brain barrier transport of morphine-3-glucuronide studied using microdialysis in the rat: involvement of probenecid-sensitive transport

    Science.gov (United States)

    Xie, Rujia; Bouw, M René; Hammarlund-Udenaes, Margareta

    2000-01-01

    The objective of this study was to investigate the impact of probenecid on the blood-brain barrier (BBB) transport of morphine-3-glucuronide (M3G). Two groups of rats received an exponential infusion of M3G over 4 h to reach a target plasma concentration of 65 μM on two consecutive days. Probenecid was co-administered in the treatment group on day 2. Microdialysis was used to estimate unbound M3G concentrations in brain extracellular fluid (ECF) and blood. In vivo recovery of M3G was calculated with retrodialysis by drug, preceding the drug administration. The BBB transport was modelled using NONMEM. In the probenecid group, the ratio of the steady-state concentration of unbound M3G in brain ECF to that in blood was 0.08±0.02 in the absence and 0.16±0.05 in the presence of probenecid (P=0.001). In the control group, no significant difference was found in this ratio between the 2 days (0.11±0.05 and 0.10±0.02, respectively). The process that appears to be mainly influenced by probenecid is influx clearance into the brain (0.11 μl min−1 g-brain−1 vs 0.17 μl min−1 g-brain−1, in the absence vs presence of probenecid, Pprobenecid. In conclusion, a probenecid-sensitive transport system is involved in the transport of M3G across the BBB. PMID:11139459

  18. PARAQUAT RESISTANT1, a Golgi-Localized Putative Transporter Protein, Is Involved in Intracellular Transport of Paraquat1[C][W

    Science.gov (United States)

    Li, Jianyong; Mu, Jinye; Bai, Jiaoteng; Fu, Fuyou; Zou, Tingting; An, Fengying; Zhang, Jian; Jing, Hongwei; Wang, Qing; Li, Zhen; Yang, Shuhua; Zuo, Jianru

    2013-01-01

    Paraquat is one of the most widely used herbicides worldwide. In green plants, paraquat targets the chloroplast by transferring electrons from photosystem I to molecular oxygen to generate toxic reactive oxygen species, which efficiently induce membrane damage and cell death. A number of paraquat-resistant biotypes of weeds and Arabidopsis (Arabidopsis thaliana) mutants have been identified. The herbicide resistance in Arabidopsis is partly attributed to a reduced uptake of paraquat through plasma membrane-localized transporters. However, the biochemical mechanism of paraquat resistance remains poorly understood. Here, we report the identification and characterization of an Arabidopsis paraquat resistant1 (par1) mutant that shows strong resistance to the herbicide without detectable developmental abnormalities. PAR1 encodes a putative l-type amino acid transporter protein localized to the Golgi apparatus. Compared with the wild-type plants, the par1 mutant plants show similar efficiency of paraquat uptake, suggesting that PAR1 is not directly responsible for the intercellular uptake of paraquat. However, the par1 mutation caused a reduction in the accumulation of paraquat in the chloroplast, suggesting that PAR1 is involved in the intracellular transport of paraquat into the chloroplast. We identified a PAR1-like gene, OsPAR1, in rice (Oryza sativa). Whereas the overexpression of OsPAR1 resulted in hypersensitivity to paraquat, the knockdown of its expression using RNA interference conferred paraquat resistance on the transgenic rice plants. These findings reveal a unique mechanism by which paraquat is actively transported into the chloroplast and also provide a practical approach for genetic manipulations of paraquat resistance in crops. PMID:23471133

  19. An aggregated indicator of air-pollution impacts involved by transports

    International Nuclear Information System (INIS)

    Goger, Th.

    2006-11-01

    We intend to build a global environmental impact indicator of air pollution to assess transport infrastructures, technologies or flows. This indicator tries to be simple and transparent to facilitate its use in decision-making. The intention is for the indicator to be like the Global Warming Potential (GWP), which establishes a relationship between the emission of six greenhouse gases and the average temperature increase of the Earth. The indicator therefore allows estimating the global environmental impact of transport-generated air pollution, while simultaneously conserving the value of the environmental impact of each type of air pollution and the emission assessment. This work is based on an environmental impact typology, a set of indicators, and aggregation architecture of atmospheric pollution. The typology is established as a function of the specific and homogenous characteristics of each type of pollution in terms of pollutants, impact mechanisms, targets and environmental impacts. To ensure exhaustiveness and non-redundancy, 10 types of air pollution impact are proposed: greenhouse effect, ozone depletion, direct eco-toxicity (this type of pollution excludes greenhouse effects on nature, ozone depletion, eutrophication, acidification and photochemical pollution), eutrophication, acidification, photochemical pollution, restricted direct health effects (not taking into account welfare, and excluding the effects on health of the greenhouse effect, ozone depletion, acidification and photochemical pollution), sensitive pollution (annoyance caused by odours and fumes), and degradation of common and historical man-made heritage. Indicators similar to GWP can be identified in the literature for each type of atmospheric pollution, except for the degradation of common and historical man-made heritage, for which none indicator have been suggested. However, these indicators do not seem to have achieved wide scientific consensus, except for GWP, which may make it

  20. Na+,K+-ATPase amino acids involved in transport of the 3rd sodium ion

    DEFF Research Database (Denmark)

    Holm, Rikke; Einholm, Anja P.; Toustrup-Jensen, Mads Schak

    . I have mutated several residues of the rat α1 isoform related to the channel structure and have characterized the effects on Na+ and K+ affinities and the E2-E1 and E1P-E2P conformational transitions of the pump cycle. Mutation D928N of rat α1, equivalent to D923N of human α3, shows a conspicuous......Available evidence indicates that two of the three Na+ ions bound in the E1 form occupy approximately the same positions as the K+ ions in E2, but the location of the third Na+ ion is unsolved. We have previously found a marked decrease in Na+ affinity for activation of phosphorylation in the human...... α3 mutant D923N, which is associated with RDP [1]. D923 is located in the cytoplasmic half of transmembrane helix M8 in a putative transport channel between M5, M7, M8 and M10. The external K+ sites behaved wild type (wt)-like in the mutant, suggesting that D923 is associated with the third Na+ ion...

  1. The Putative Response Regulator BaeR Stimulates Multidrug Resistance of Escherichia coli via a Novel Multidrug Exporter System, MdtABC

    OpenAIRE

    Nagakubo, Satoshi; Nishino, Kunihiko; Hirata, Takahiro; Yamaguchi, Akihito

    2002-01-01

    Overproduction of the response regulator BaeR confers resistance to novobiocin and bile salts in a ΔacrAB mutant by stimulating drug exporter gene expression. The mdtABC (multidrug transporter ABC, formerly known as yegMNO) genes, which encode a resistance-nodulation-cell division (RND) drug efflux system, are responsible for resistance. The MdtABC system comprises the transmembrane MdtB/MdtC heteromultimer and MdtA membrane fusion protein. MdtAC also confers bile salt, but not novobiocin, re...

  2. Regulatory pathways for ATP-binding cassette transport proteins in kidney proximal tubules

    NARCIS (Netherlands)

    Masereeuw, R.; Russel, F.G.M.

    2012-01-01

    The ATP-binding cassette transport proteins (ABC transporters) represent important determinants of drug excretion. Protective or excretory tissues where these transporters mediate substrate efflux include the kidney proximal tubule. Regulation of the transport proteins in this tissue requires

  3. A common highly conserved cadmium detoxification mechanism from bacteria to humans: heavy metal tolerance conferred by the ATP-binding cassette (ABC) transporter SpHMT1 requires glutathione but not metal-chelating phytochelatin peptides.

    Science.gov (United States)

    Prévéral, Sandra; Gayet, Landry; Moldes, Cristina; Hoffmann, Jonathan; Mounicou, Sandra; Gruet, Antoine; Reynaud, Florie; Lobinski, Ryszard; Verbavatz, Jean-Marc; Vavasseur, Alain; Forestier, Cyrille

    2009-02-20

    Cadmium poses a significant threat to human health due to its toxicity. In mammals and in bakers' yeast, cadmium is detoxified by ATP-binding cassette transporters after conjugation to glutathione. In fission yeast, phytochelatins constitute the co-substrate with cadmium for the transporter SpHMT1. In plants, a detoxification mechanism similar to the one in fission yeast is supposed, but the molecular nature of the transporter is still lacking. To investigate further the relationship between SpHMT1 and its co-substrate, we overexpressed the transporter in a Schizosaccharomyces pombe strain deleted for the phytochelatin synthase gene and heterologously in Saccharomyces cerevisiae and in Escherichia coli. In all organisms, overexpression of SpHMT1 conferred a markedly enhanced tolerance to cadmium but not to Sb(III), AgNO(3), As(III), As(V), CuSO(4), or HgCl(2). Abolishment of the catalytic activity by expression of SpHMT1(K623M) mutant suppressed the cadmium tolerance phenotype independently of the presence of phytochelatins. Depletion of the glutathione pool inhibited the SpHMT1 activity but not that of AtHMA4, a P-type ATPase, indicating that GSH is necessary for the SpHMT1-mediated cadmium resistance. In E. coli, SpHMT1 was targeted to the periplasmic membrane and led to an increased amount of cadmium in the periplasm. These results demonstrate that SpHMT1 confers cadmium tolerance in the absence of phytochelatins but depending on the presence of GSH and ATP. Our results challenge the dogma of the two separate cadmium detoxification pathways and demonstrate that a common highly conserved mechanism has been selected during the evolution from bacteria to humans.

  4. Modelling of contact problems involved in ensuring the safety of rail transport

    Directory of Open Access Journals (Sweden)

    Edward Rydygier

    2013-12-01

    Full Text Available Background: Mathematical modelling aids diagnostics the track and rolling stock, as it often for technical reasons it is not possible to obtain a complete set of measurement data required to diagnose the rail and wheel deformation caused by the impact of a rail vehicle on the track. The important issue in a railway diagnostics is to study the effects of contact wheel and rail. Diagnostics investigations of track and rolling stock have a fundamental role in ensuring the safety of transport of passengers and goods. The aim of the study presented in the paper was to develop simulation methods of mathematical modelling of the wheel-rail system useful in the diagnostics of the track and a railway vehicle. Methods: In the paper two ways of modelling were presented and discussed. One of these ways is the method which consists in reducing the contact issue to field issue and solving the identification of the field source in 2-D system. Also presented a different method designed on the basis of the methods using one period energy concept. This method is adapted for modelling the dynamics of the contact wheel-rail for the normal force. It has been shown that the developed modelling methods to effectively support the study on the effects of mechanical and thermal of contact wheel-rail and contribute to the safety of operations.  Results and conclusions:  In the case of field sources identifications two specific issues were examined: the issue of rail torsion and the identification of heat sources in the rail due to exposure the rolling contact wheel-rail. In the case of the method using one period energy concept it was demonstrated the usefulness of this method to the study of energy processes in the contact wheel-rail under the normal periodic force. The future direction of research is to establish cooperation with research teams entrusted with the diagnostic measurements of track and rolling stock.  

  5. Inhibition of beta-amino acid transport by diamide does not involve the brush border membrane surface

    International Nuclear Information System (INIS)

    Chesney, R.W.; Gusowski, N.; Albright, P.

    1985-01-01

    Diamide (dicarboxylic acid bis-(N,N-dimethylamide) has been shown in previous studies to block the uptake of the beta-amino acid taurine at its high affinity transport site in rat renal cortex slices. Diamide may act by increasing the efflux of taurine from the slice. Studies performed in rat slices again indicate enhanced efflux over 8-12 minutes. The time course of reduced glutathione (GSH) depletion from renal cortex is similar, indicating a potential interaction between GSH depletion and inhibition of taurine accumulation. The effect of 9 mM diamide on the Na+ -dependent accumulation of taurine (10 and 250 microM) by brush border membrane vesicles was examined, and the taurine uptake value both initially and at equilibrium was the same in the presence and absence of diamide. Isolation of the brush border surface and subsequent transport studies of taurine are not influenced by diamide. Thus, diamide inhibition of taurine uptake does not involve physiochemical alteration of the membrane surface where active amino acid transport occurs, despite the thiol-oxidizing properties of this agent. Further, these studies suggest that diamide either acts at the basolateral surface, rather than the brush border surface of rat renal cortex or requires the presence of an intact tubule, capable of metabolism, prior to its inhibitory action

  6. Specificity of drug transport mediated by CaMDR1: a major facilitator ...

    Indian Academy of Sciences (India)

    Unknown

    among these two tested drugs. Due to severe toxicity of these drugs to insect cells, further characterization of. CaMdr1p as a drug transporter could not be done with this system. Therefore, as an alternative, CaMdr1p and. Cdr1p, which is an ABC protein (ATP binding cassette) also involved in azole resistance in C. albicans, ...

  7. Organic cation transporter 1 (OCT1 is involved in pentamidine transport at the human and mouse blood-brain barrier (BBB.

    Directory of Open Access Journals (Sweden)

    Gayathri N Sekhar

    Full Text Available Pentamidine is an effective trypanocidal drug used against stage 1 Human African Trypanosomiasis (HAT. At the blood-brain barrier (BBB, it accumulates inside the endothelial cells but has limited entry into the brain. This study examined transporters involved in pentamidine transport at the human and mouse BBB using hCMEC/D3 and bEnd.3 cell lines, respectively. Results revealed that both cell lines expressed the organic cation transporters (OCT1, OCT2 and OCT3, however, P-gp was only expressed in hCMEC/D3 cells. Polarised expression of OCT1 was also observed. Functional assays found that ATP depletion significantly increased [3H]pentamidine accumulation in hCMEC/D3 cells (***p<0.001 but not in bEnd.3 cells. Incubation with unlabelled pentamidine significantly decreased accumulation in hCMEC/D3 and bEnd.3 cells after 120 minutes (***p<0.001. Treating both cell lines with haloperidol and amantadine also decreased [3H]pentamidine accumulation significantly (***p<0.001 and **p<0.01 respectively. However, prazosin treatment decreased [3H]pentamidine accumulation only in hCMEC/D3 cells (*p<0.05, and not bEnd.3 cells. Furthermore, the presence of OCTN, MATE, PMAT, ENT or CNT inhibitors/substrates had no significant effect on the accumulation of [3H]pentamidine in both cell lines. From the data, we conclude that pentamidine interacts with multiple transporters, is taken into brain endothelial cells by OCT1 transporter and is extruded into the blood by ATP-dependent mechanisms. These interactions along with the predominant presence of OCT1 in the luminal membrane of the BBB contribute to the limited entry of pentamidine into the brain. This information is of key importance to the development of pentamidine based combination therapies which could be used to treat CNS stage HAT by improving CNS delivery, efficacy against trypanosomes and safety profile of pentamidine.

  8. Loss of plastoglobule kinases ABC1K1 and ABC1K3 causes conditional degreening, modified prenyl-lipids, and recruitment of the jasmonic acid pathway

    Science.gov (United States)

    Plastoglobules (PGs) are plastid lipid-protein particles. This study examines the function of PG-localized kinases ABC1K1 and ABC1K3 in Arabidopsis thaliana. Several lines of evidence suggested that ABC1K1 and ABC1K3 form a protein complex. Null mutants for both genes (abc1k1 and abc1k3) and the dou...

  9. The proton-coupled amino acid transporter hPAT1 is the main transporter involved in vigabatrin uptake in intestinal Caco-2 cells

    DEFF Research Database (Denmark)

    Nøhr, Martha Kampp; Hansen, Steen Honore'; Brodin, Birger

    2012-01-01

    transporter hPAT1. The aim of the project was to identify if transporters are involved in cellular uptake of vigabatrin in Caco-2 cells. Methods: The uptake rate of vigabatrin was measured in Caco-2 cells at pH 6.0 or 7.4 for 15 min after application of 0.1 – 25.0 mM vigabatrin. The inhibitory effect...... of selected amino acids and -derivatives on the apical vigabatrin uptake in Caco-2 cells was investigated. Vigabatrin samples were analyzed using liquid chromatography (LC) coupled to a mass selective detector (MSD). Results: The uptake rate of vigabatrin in Caco-2 cells was pH-dependent. The uptake...... of vigabatrin was saturable at pH 6.0 with a Michaelis constant, Km of 12.7 ± 3.7 mM and a maximal flux, Jmax of 3.7 ± 0.5 nmol•min-1•cm-2. The presences of hPAT1 ligands significantly inhibited the uptake of vigabatrin in Caco-2 cells at pH 6.0, whereas hPAT1 non-ligands did not. Discussion: The saturability...

  10. Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR.

    Science.gov (United States)

    Moretti, Marcelo L; Alárcon-Reverte, Rocio; Pearce, Stephen; Morran, Sarah; Hanson, Bradley D

    2017-01-01

    Herbicide resistance is a challenge for modern agriculture further complicated by cases of resistance to multiple herbicides. Conyza bonariensis and Conyza canadensis are invasive weeds of field crops, orchards, and non-cropped areas in many parts of the world. In California, USA, Conyza populations resistant to the herbicides glyphosate and paraquat have recently been described. Although the mechanism conferring resistance to glyphosate and paraquat in these species was not elucidated, reduced translocation of these herbicides was observed under experimental conditions in both species. Glyphosate and paraquat resistance associated with reduced translocation are hypothesized to be a result of sequestration of herbicides into the vacuole, with the possible involvement of over-expression of genes encoding tonoplast transporters of ABC-transporter families in cases of glyphosate resistance or cationic amino acid transporters (CAT) in cases of paraquat resistance. However, gene expression in response to herbicide treatment has not been studied in glyphosate and paraquat resistant populations. In the current study, we evaluated the transcript levels of genes possibly involved in resistance using real-time PCR. First, we evaluated eight candidate reference genes following herbicide treatment and selected three genes that exhibited stable expression profiles; ACTIN, HEAT-SHOCK-PROTEIN-70, and CYCLOPHILIN. The reference genes identified here can be used for further studies related to plant-herbicide interactions. We used these reference genes to assay the transcript levels of EPSPS, ABC transporters, and CAT in response to herbicide treatment in susceptible and resistant Conyza spp. lines. No transcription changes were observed in EPSPS or CAT genes after glyphosate or paraquat treatment, suggesting that these genes are not involved in the resistance mechanism. Transcription of the two ABC transporter genes increased following glyphosate treatment in all Conyza spp. lines

  11. Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing

    Science.gov (United States)

    López, Maria; Blasco, Lucia; Gato, Eva; Perez, Astrid; Fernández-Garcia, Laura; Martínez-Martinez, Luis; Fernández-Cuenca, Felipe; Rodríguez-Baño, Jesús; Pascual, Alvaro; Bou, German; Tomás, Maria

    2017-01-01

    Introduction: Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A. baumannii are scarce. Material and Methods: Microbiological and transcriptional studies (arrays and RT-PCR) in the response to bile salts were carried out in isogenic (A. baumanni ΔadeB ATCC 17978 and A. baumannii ΔadeL ATCC 17978) and clinical strains from clone ST79/PFGE-HUI-1 which is characterized by lacking the AdeABC efflux pump and by overexpression the AdeFGH efflux pump. Results and Discussion: In presence of bile salts, in addition to the glutamate/aspartate transporter were found overexpressed in A. baumannii ΔadeB ATCC 17978, the virulence factors (surface motility, biofilm, and Type VI Secretion System) which are associated with activation of the Quorum Sensing system. Overexpression of these factors was confirmed in clinical strains of clone ST79/PFGE-HUI-1. Conclusions: This the first study about the adaptive response to bile salts investigating the molecular and microbiological characteristics in response to bile salts of an isogenic model of A. baumannii ATCC 17978 and clinical isolates of A. baumannii (clinical strains of ST79/PFGE-HUI-1) lacking the main RND efflux pump (AdeABC). Clinical isolates of A. baumannii lacking the AdeABC efflux pump (clone ST79/PFGE-HUI-1) displayed a new clinical profile (increased invasiveness) possibly associated with the response to stress conditions (such as the presence of bile salts). PMID:28536672

  12. Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing.

    Science.gov (United States)

    López, Maria; Blasco, Lucia; Gato, Eva; Perez, Astrid; Fernández-Garcia, Laura; Martínez-Martinez, Luis; Fernández-Cuenca, Felipe; Rodríguez-Baño, Jesús; Pascual, Alvaro; Bou, German; Tomás, Maria

    2017-01-01

    Introduction: Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A. baumannii are scarce. Material and Methods: Microbiological and transcriptional studies (arrays and RT-PCR) in the response to bile salts were carried out in isogenic ( A. baumanni Δ adeB ATCC 17978 and A. baumannii Δ adeL ATCC 17978) and clinical strains from clone ST79/PFGE-HUI-1 which is characterized by lacking the AdeABC efflux pump and by overexpression the AdeFGH efflux pump. Results and Discussion: In presence of bile salts, in addition to the glutamate/aspartate transporter were found overexpressed in A. baumannii Δ adeB ATCC 17978, the virulence factors (surface motility, biofilm, and Type VI Secretion System) which are associated with activation of the Quorum Sensing system. Overexpression of these factors was confirmed in clinical strains of clone ST79/PFGE-HUI-1. Conclusions: This the first study about the adaptive response to bile salts investigating the molecular and microbiological characteristics in response to bile salts of an isogenic model of A. baumannii ATCC 17978 and clinical isolates of A. baumannii (clinical strains of ST79/PFGE-HUI-1) lacking the main RND efflux pump (AdeABC). Clinical isolates of A. baumannii lacking the AdeABC efflux pump (clone ST79/PFGE-HUI-1) displayed a new clinical profile (increased invasiveness) possibly associated with the response to stress conditions (such as the presence of bile salts).

  13. Effect of the deletion of qmoABC and the promoter distal gene encoding a hypothetical protein on sulfate-reduction in Desulfovibrio vulgaris Hildenborough

    Energy Technology Data Exchange (ETDEWEB)

    Zane, Grant M.; Yen, Huei-chi Bill; Wall, Judy D.

    2010-03-18

    The pathway of electrons required for the reduction of sulfate in sulfate-reducing bacteria (SRB) is not yet fully characterized. In order to determine the role of a transmembrane protein complex suggested to be involved in this process, a deletion of Desulfovibrio vulgaris Hildenborough was created by marker exchange mutagenesis that eliminated four genes putatively encoding the QmoABC complex and a hypothetical protein (DVU0851). The Qmo complex (quinone-interacting membrane-bound oxidoreductase) is proposed to be responsible for transporting electrons to the dissimilatory adenosine-5?phosphosulfate (APS) reductase in SRB. In support of the predicted role of this complex, the deletion mutant was unable to grow using sulfate as its sole electron acceptor with a range of electron donors. To explore a possible role for the hypothetical protein in sulfate reduction, a second mutant was constructed that had lost only the gene that codes for DVU0851. The second constructed mutant grew with sulfate as the sole electron acceptor; however, there was a lag that was not present with the wild-type or complemented strain. Neither deletion strain was significantly impaired for growth with sulfite or thiosulfate as terminal electron acceptor. Complementation of the D(qmoABC-DVU0851) mutant with all four genes or only the qmoABC genes restored its ability to grow by sulfate respiration. These results confirmed the prediction that the Qmo complex is in the electron pathway for sulfate-reduction and revealed that no other transmembrane complex could compensate when Qmo was lacking.

  14. The ABC of ABC-transport in the hyperthermophilic archaeon Pyrococcus furiosus

    NARCIS (Netherlands)

    Koning, S

    2003-01-01

    Living organisms of our earth can be divided into two groups, the prokaryotes and the eukaryotes. Eukaryotic cells have a nucleus, a special compartment in the cell, where the genetic material, the DNA is located. The DNA in the prokaryotic cell is floating freely in the cell. The eukaryotes, that

  15. Sucrose transporter NtSUT4 from tobacco BY-2 involved in plant cell shape during miniprotoplast culture.

    Science.gov (United States)

    Okubo-Kurihara, Emiko; Higaki, Takumi; Kurihara, Yukio; Kutsuna, Natsumaro; Yamaguchi, Junji; Hasezawa, Seiichiro

    2011-05-01

    Sucrose plays an important role in several cellular processes since it is a general source of metabolic energy, serves as a precursor for starch and cellulose synthesis, and is a metabolic starting point for carboxylate- and amino acid synthesis. While plant vacuole is the main cellular storage pool, where sucrose accumulates to high concentrations, only a small number of vacuolar sugar transporters have been identified and characterized to date. We initially identified a vacuolar sucrose transporter (NtSUT4) from tobacco BY-2 cells and established transgenic tobacco BY-2 cell lines that overexpress NtSUT4-GFP (BY-SUTG cells). Using a model system for synchronous cell elongation in miniprotoplasts (evacuolated cells) prepared from tobacco BY-2 cells, we found that NtSUT4-GFP overexpression inhibited cell growth towards the cell major axis. Moreover, under the same conditions, we found that the cell walls were well stained by calcofluor in BY-SUTG cells than in wild type BY-2 cells. These results suggest that NtSUT4 is involved in cell shape via sucrose homeostasis in plant cells.

  16. Nuclear Liability and Insurance Protection for Nuclear Transport Accidents Involving Non-Contracting EU States: An assessment

    International Nuclear Information System (INIS)

    Horbach, N. L. J. T.

    2006-01-01

    This paper provides an analysis of the possible complications and consequences with respect to nuclear liability and insurance protection applicable in respect of transport activities resulting in damage suffered and/or accidents occurring in EU States that are not party to the Paris Convention. It looks at the different legal aspects (jurisdiction, applicable law, liability amounts, reciprocity) should the revised Vienna and Paris Convention become applicable in comparison with the unrevised Conventions. Within Europe, a large number of States are party to the 1960 Paris Convention and the 1963 Brussels Supplementary Convention, providing liability and insurance protection, in general, up to a limit of 300 million SDRs (or even higher). In principle, such protection is confined to nuclear incidents occurring and nuclear damage suffered in the territory of Contracting Parties, including, as recommended, the high seas, unless the legislation of the Installation State determines otherwise (Article 2). The geographical scope of application of the Paris Convention would thus vary according to the law of the Installation State. However, some EU States never became party to the Paris Convention, and are not bound by its the liability principles (notably, channelling of liability), such as Austria, Luxembourg and Ireland. Transport accidents involving these countries might therefore result in liability claims outside the treaty liability regime against operators, suppliers, carriers or persons involved and for types of damages different from those currently covered by the Paris Convention (e.g., environmental damage). It is uncertain to what extent liability insurance of the installation operators would provide adequate protection and whether related damage claims can be enforceable. In addition, a number of newly entered EU States are party to the Vienna Convention, which, although bound by liability principles basically similar to those of the Paris Convention, will

  17. The Role of the Actin Cytoskeleton and Lipid Rafts in the Localization and Function of the ABCC1 Transporter

    Directory of Open Access Journals (Sweden)

    Jan Willem Kok

    2014-01-01

    Full Text Available ATP-binding cassette (ABC transporters are known to be important factors in multidrug resistance of tumor cells. Lipid rafts have been implicated in their localization in the plasma membrane, where they function as drug efflux pumps. This specific localization in rafts may support the activity of ABC/Abc transporters. This raises questions regarding the nature and composition of the lipid rafts that harbor ABC/Abc transporters and the dependence of ABC/Abc transporters—concerning their localization and activity—on lipid raft constituents. Here we review our work of the past 10 years aimed at evaluating whether ABC/Abc transporters are dependent on a particular membrane environment for their function. What is the nature of this membrane environment and which of the lipid raft constituents are important for this dependency? It turns out that cortical actin is of major importance for stabilizing the localization and function of the ABC/Abc transporter, provided it is localized in an actin-dependent subtype of lipid rafts, as is the case for human ABCC1/multidrug resistance-related protein 1 (MRP1 and rodent Abcc1/Mrp1 but not human ABCB1/P-glycoprotein (PGP. On the other hand, sphingolipids do not appear to be modulators of ABCC1/MRP1 (or Abcc1/Mrp1, even though they are coregulated during drug resistance development.

  18. Arabidopsis Transporter ABCG37/PDR9 contributes primarily highly oxygenated Coumarins to Root Exudation.

    Science.gov (United States)

    Ziegler, Jörg; Schmidt, Stephan; Strehmel, Nadine; Scheel, Dierk; Abel, Steffen

    2017-06-16

    The chemical composition of root exudates strongly impacts the interactions of plants with microorganisms in the rhizosphere and the efficiency of nutrient acquisition. Exudation of metabolites is in part mediated by ATP-binding cassette (ABC) transporters. In order to assess the contribution of individual ABC transporters to root exudation, we performed an LC-MS based non-targeted metabolite profiling of semi-polar metabolites accumulating in root exudates of Arabidopsis thaliana plants and mutants deficient in the expression of ABCG36 (PDR8/PEN3), ABCG37 (PDR9) or both transporters. Comparison of the metabolite profiles indicated distinct roles for each ABC transporter in root exudation. Thymidine exudation could be attributed to ABCG36 function, whereas coumarin exudation was strongly reduced only in ABCG37 deficient plants. However, coumarin exudation was compromised in abcg37 mutants only with respect to certain metabolites of this substance class. The specificity of ABCG37 for individual coumarins was further verified by a targeted LC-MS based coumarin profiling method. The response to iron deficiency, which is known to strongly induce coumarin exudation, was also investigated. In either treatment, the distribution of individual coumarins between roots and exudates in the investigated genotypes suggested the involvement of ABCG37 in the exudation specifically of highly oxygenated rather than monohydroxylated coumarins.

  19. Involvement of the ABC transporter BcAtrB and the laccase BcLCC2 in defence of Botrytis cinerea against the broad-spectrum antibiotic 2,4-diacetylphloroglucinol

    NARCIS (Netherlands)

    Schouten, A.; Maksimova, O.; Cuesta Arenas, Y.; Berg, van den G.; Raaijmakers, J.M.

    2008-01-01

    The genetic and biochemical basis of defence mechanisms in plant pathogenic fungi against antifungal compounds produced by antagonistic microorganisms is largely unknown. The results of this study show that both degradative and non-degradative defence mechanisms enable the plant pathogenic fungus

  20. Nonlinear resonances in the ABC-flow

    Science.gov (United States)

    Didov, A. A.; Uleysky, M. Yu.

    2018-01-01

    In this paper, we study resonances of the ABC-flow in the near integrable case ( C ≪1 ). This is an interesting example of a Hamiltonian system with 3/2 degrees of freedom in which simultaneous existence of two resonances of the same order is possible. Analytical conditions of the resonance existence are received. It is shown numerically that the largest n :1 (n = 1, 2, 3) resonances exist, and their energies are equal to theoretical energies in the near integrable case. We provide analytical and numerical evidences for existence of two branches of the two largest n :1 (n = 1, 2) resonances in the region of finite motion.

  1. Effects of ginsenosides on the expression of cytochrome P450s and transporters involved in cholesterol metabolism.

    Science.gov (United States)

    Kawase, Atsushi; Yamada, Ayano; Gamou, Yuko; Tahara, Chika; Takeshita, Fumiaki; Murata, Kazuya; Matsuda, Hideaki; Samukawa, Keiichi; Iwaki, Masahiro

    2014-04-01

    An extract from red ginseng (steamed and dried roots of Panax ginseng C.A. Meyer; RGE) has been shown to promote cholesterol metabolism in the liver. We have reported that RGE induced the hepatic expression of cytochrome P450 (CYP)7A1, involved in cholesterol metabolism. Other cholesterol metabolism-related proteins, such as CYP8B1, CYP27A1, multidrug resistance-associated protein (MRP)2, MRP3, and Na(+) taurocholate cotransporting polypeptide (NTCP), are involved in cholesterol metabolism. The purpose of this study was to clarify whether RGE affected mRNA expression of cholesterol metabolism-related CYPs and transporters in the liver of hypercholesterolemic rats and rat primary hepatocytes. In-vivo studies showed little differences in CYP8B1, CYP27A1, MRP2, MRP3, and NTCP mRNA expression levels between hypercholesterolemic rats with or without RGE treatments. However, the disruption of the membrane localization of MRP2 was suppressed by RGE treatments in hypercholesterolemic rats. In-vitro studies using rat primary hepatocytes showed upregulation of CYP8B1 and MRP2 mRNA by the addition of RGE (100 and 500 μg/mL). We further examined which ginsenosides contributed to the upregulation of CYP8B1 and MRP2 mRNA levels. Ginsenoside Re enhanced the mRNA level of CYP8B1, whereas ginsenosides Rb2 and Rg2 enhanced MRP2 mRNA levels. These results suggest that the in-vitro exposure of hepatocytes to RGE or some ginsenosides could lead to upregulation of CYP8B1 and MRP2, resulting in the alteration of biosynthesis and disposition of bile acids.

  2. Amino acid residues involved in ligand preference of the Snf3 transporter-like sensor in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Dietvorst, J.; Karhumaa, Kaisa; Kielland-Brandt, Morten

    2010-01-01

    Snf3 is a plasma membrane protein in Saccharomyces cerevisiae cerevisiae able to sense the presence of glucose. Although the Snf3 protein does not transport sugars, it shares sequence similarity with various glucose transporters from other organisms. we investigated the sugar specificity/preferen...... used for facilitated hexose transport in the GLUT proteins....

  3. Flavonoids as modulators of metabolic enzymes and drug transporters.

    Science.gov (United States)

    Miron, Anca; Aprotosoaie, Ana Clara; Trifan, Adriana; Xiao, Jianbo

    2017-06-01

    Flavonoids, natural compounds found in plants and in plant-derived foods and beverages, have been extensively studied with regard to their capacity to modulate metabolic enzymes and drug transporters. In vitro, flavonoids predominantly inhibit the major phase I drug-metabolizing enzyme CYP450 3A4 and the enzymes responsible for the bioactivation of procarcinogens (CYP1 enzymes) and upregulate the enzymes involved in carcinogen detoxification (UDP-glucuronosyltransferases, glutathione S-transferases (GSTs)). Flavonoids have been reported to inhibit ATP-binding cassette (ABC) transporters (multidrug resistance (MDR)-associated proteins, breast cancer-resistance protein) that contribute to the development of MDR. P-glycoprotein, an ABC transporter that limits drug bioavailability and also induces MDR, was differently modulated by flavonoids. Flavonoids and their phase II metabolites (sulfates, glucuronides) inhibit organic anion transporters involved in the tubular uptake of nephrotoxic compounds. In vivo studies have partially confirmed in vitro findings, suggesting that the mechanisms underlying the modulatory effects of flavonoids are complex and difficult to predict in vivo. Data summarized in this review strongly support the view that flavonoids are promising candidates for the enhancement of oral drug bioavailability, chemoprevention, and reversal of MDR. © 2017 New York Academy of Sciences.

  4. Diversity of transport mechanisms: common structural principles

    NARCIS (Netherlands)

    Driessen, A.J.M.; Rosen, B.P.; Konings, W.N

    2000-01-01

    Traditionally, prokaryotic solute transport systems are classified into major groups based on the energetic requirement of the transport process. These include the secondary transporters that are driven by a proton or sodium motive force, and the ATP-binding cassette (ABC) primary transporters,

  5. ABC's "Person of the Week": American Values in Television News.

    Science.gov (United States)

    Larson, Stephanie Greco; Bailey, Martha

    1998-01-01

    Contributes to scholarship on values and ideologies in the media by analyzing five years of ABC's "Person of the Week" segments to identify prominent types of people and values endorsed by mainstream news media. Finds that individuals most frequently selected for ABC's honor lived in the United States; worked in politics and…

  6. Measuring Academic Behavioural Confidence: The ABC Scale Revisited

    Science.gov (United States)

    Sander, Paul; Sanders, Lalage

    2009-01-01

    The Academic Behavioural Confidence (ABC) scale has been shown to be valid and can be useful to teachers in understanding their students, enabling the design of more effective teaching sessions with large cohorts. However, some of the between-group differences have been smaller than expected, leading to the hypothesis that the ABC scale many not…

  7. Dashboard Auditing of Activity-Based Costing (ABC

    Directory of Open Access Journals (Sweden)

    Sorinel Capusneanu

    2009-03-01

    Full Text Available This article aims to define the dashboard auditing according to the specifics of Activity-Based Costing method (ABC. It describes the main objectives of dashboard auditing, the criteria that a dashboard auditor should meet and the step-by-step stages of the entire dashboard auditing process according to the Activity-Based Costing method (ABC.

  8. Dashboard Auditing of Activity-Based Costing (ABC)

    OpenAIRE

    Sorinel Capusneanu

    2009-01-01

    This article aims to define the dashboard auditing according to the specifics of Activity-Based Costing method (ABC). It describes the main objectives of dashboard auditing, the criteria that a dashboard auditor should meet and the step-by-step stages of the entire dashboard auditing process according to the Activity-Based Costing method (ABC).

  9. Dashboard auditing of ABC (Activity-Based Costing). Theoretical approaches

    OpenAIRE

    Căpuşneanu, Sorinel/I

    2009-01-01

    This article aims to define the dashboard auditing according to the specifics of Activity-Based Costing method (ABC). It describes the main objectives of dashboard auditing, the criteria that a dashboard auditor should meet and the step-by-step stages of the entire dashboard auditing process of an enterprise from steel industry according to the Activity-Based Costing method (ABC).

  10. Transportation

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Here is the decree of the thirtieth of July 1998 relative to road transportation, to trade and brokerage of wastes. It requires to firms which carry out a road transportation as well as to traders and to brokers of wastes to declare their operations to the prefect. The declaration has to be renewed every five years. (O.M.)

  11. Sustained Delivery of Chondroitinase ABC from Hydrogel System

    Directory of Open Access Journals (Sweden)

    Filippo Rossi

    2012-03-01

    Full Text Available In the injured spinal cord, chondroitin sulfate proteoglycans (CSPGs are the principal responsible of axon growth inhibition and they contribute to regenerative failure, promoting glial scar formation. Chondroitinase ABC (chABC is known for being able to digest proteoglycans, thus degrading glial scar and favoring axonal regrowth. However, its classic administration is invasive, infection-prone and clinically problematic. An agarose-carbomer (AC1 hydrogel, already used in SCI repair strategies, was here investigated as a delivery system capable of an effective chABC administration: the material ability to include chABC within its pores and the possibility to be injected into the target tissue were firstly proved. Subsequently, release kinetic and the maintenance of enzymatic activity were positively assessed: AC1 hydrogel was thus confirmed to be a feasible tool for chABC delivery and a promising device for spinal cord injury topic repair strategies.

  12. Soybean SAT1 (Symbiotic Ammonium Transporter 1) encodes a bHLH transcription factor involved in nodule growth and NH4+ transport

    NARCIS (Netherlands)

    Chiasson, D.M.; Loughlin, P.C.; Mazurkiewicz, D.; Mohammadidehcheshmeh, M.; Fedorova, E.E.; Okamoto, M.; McLean, E.; Glass, A.D.M.; Smith, S.E.; Bisseling, T.; Tyerman, S.D.; Day, D.A.; Kaiser, B.N.

    2014-01-01

    Glycine max symbiotic ammonium transporter 1 was first documented as a putative ammonium (NH4+) channel localized to the symbiosome membrane of soybean root nodules. We show that Glycine max symbiotic ammonium transporter 1 is actually a membrane-localized basic helix–loop–helix (bHLH) DNA-binding

  13. ABC transporters and multidrug resistance in Aspergillus nidulans

    NARCIS (Netherlands)

    Andrade, A.C.

    2000-01-01

    The term multidrug resistance (MDR) stands for simultaneous cellular resistance to chemically unrelated toxicants and is often associated with overproduction of multidrug-efflux proteins of the A TP- b inding-

  14. The ABC of ABC : An analysis of attribute-based credentials in the light of data protection, privacy and identity.

    NARCIS (Netherlands)

    Korenhof, P.E.I.; Koning, Merel; Alpár, Gergely; Hoepman, J.H.; Padullés, Joan Balcells; i Martínez, Agustí Cerrillo; Poch, Miquel Peguera; López, Ismael Peña; de Moner, María José Pifarré; Solana, Mònica Vilasau

    2014-01-01

    Our networked society increasingly needs secure identity sys- tems. The Attribute-based credential (ABC) technology is designed to be privacy-friendlier than contemporary authentication methods, which often suffer from information leakage. So far, however, some of the wider implications of ABC have

  15. Local Delivery of High-Dose Chondroitinase ABC in the Sub-Acute Stage Promotes Axonal Outgrowth and Functional Recovery after Complete Spinal Cord Transection.

    Directory of Open Access Journals (Sweden)

    Chu-Hsun Cheng

    Full Text Available Chondroitin sulfate proteoglycans (CSPGs are glial scar-associated molecules considered axonal regeneration inhibitors and can be digested by chondroitinase ABC (ChABC to promote axonal regeneration after spinal cord injury (SCI. We previously demonstrated that intrathecal delivery of low-dose ChABC (1 U in the acute stage of SCI promoted axonal regrowth and functional recovery. In this study, high-dose ChABC (50 U introduced via intrathecal delivery induced subarachnoid hemorrhage and death within 48 h. However, most SCI patients are treated in the sub-acute or chronic stages, when the dense glial scar has formed and is minimally digested by intrathecal delivery of ChABC at the injury site. The present study investigated whether intraparenchymal delivery of ChABC in the sub-acute stage of complete spinal cord transection would promote axonal outgrowth and improve functional recovery. We observed no functional recovery following the low-dose ChABC (1 U or 5 U treatments. Furthermore, animals treated with high-dose ChABC (50 U or 100 U showed decreased CSPGs levels. The extent and area of the lesion were also dramatically decreased after ChABC treatment. The outgrowth of the regenerating axons was significantly increased, and some partially crossed the lesion site in the ChABC-treated groups. In addition, retrograde Fluoro-Gold (FG labeling showed that the outgrowing axons could cross the lesion site and reach several brain stem nuclei involved in sensory and motor functions. The Basso, Beattie and Bresnahan (BBB open field locomotor scores revealed that the ChABC treatment significantly improved functional recovery compared to the control group at eight weeks after treatment. Our study demonstrates that high-dose ChABC treatment in the sub-acute stage of SCI effectively improves glial scar digestion by reducing the lesion size and increasing axonal regrowth to the related functional nuclei, which promotes locomotor recovery. Thus, our results

  16. Erythropoietin Increases Myelination in Oligodendrocytes: Gene Expression Profiling Reveals Early Induction of Genes Involved in Lipid Transport and Metabolism

    Directory of Open Access Journals (Sweden)

    Georgina Gyetvai

    2017-10-01

    Full Text Available Several studies have shown that erythropoietin (EPO has neuroprotective or neuroreparative actions on diseases of the nervous system and that improves oligodendrocyte (OL differentiation and myelination in vivo and in vitro. This study aims at investigating the early molecular mechanisms for the pro-myelinating action of EPO at the gene expression level. For this purpose, we used a differentiating OL precursor cell line, rat central glia-4 cells. Cells were differentiated or not, and then treated with EPO for 1 or 20 h. RNA was extracted and changes in the gene expression profile were assessed using microarray analysis. Experiments were performed in biological replicates of n = 4. Differentiation alone changed the expression of 11% of transcripts (2,663 out of 24,272, representing 2,436 genes, half of which were upregulated and half downregulated. At 20 h of treatment, EPO significantly affected the expression of 99 genes that were already regulated by differentiation and of 150 genes that were not influenced by differentiation alone. Analysis of the transcripts most upregulated by EPO identified several genes involved in lipid transport (e.g., Cd36 and lipid metabolism (Ppargc1a/Pgc1alpha, Lpin1, Pnlip, Lpin2, Ppard, Plin2 along with Igf1 and Igf2, growth factors known for their pro-myelinating action. All these genes were only induced by EPO and not by differentiation alone, except for Pnlip which was highly induced by differentiation and augmented by EPO. Results were validated by quantitative PCR. These findings suggest that EPO might increase remyelination by inducing insulin-like growth factors and increasing lipid metabolism.

  17. Transportation

    National Research Council Canada - National Science Library

    Allshouse, Michael; Armstrong, Frederick Henry; Burns, Stephen; Courts, Michael; Denn, Douglas; Fortunato, Paul; Gettings, Daniel; Hansen, David; Hoffman, Douglas; Jones, Robert

    2007-01-01

    .... The ability of the global transportation industry to rapidly move passengers and products from one corner of the globe to another continues to amaze even those wise to the dynamics of such operations...

  18. Bacterial multidrug resistance mediated by a homologue of the human multidrug transporter P-glycoprotein

    NARCIS (Netherlands)

    Konings, WN; Poelarends, GJ

    2002-01-01

    Most ATP-binding cassette (ABC) multidrug transporters known to date are of eukaryotic origin, such as the P-glycoproteins (Pgps) and multidrug resistance-associated proteins (MRPs). Only one well-characterized ABC multidrug transporter, LmrA, is of bacterial origin. On the basis of its structural

  19. ABCA Transporter Gene Expression and Poor Outcome in Epithelial Ovarian Cancer

    DEFF Research Database (Denmark)

    Hedditch, Ellen L; Gao, Bo; Russell, Amanda J

    2014-01-01

    BACKGROUND: ATP-binding cassette (ABC) transporters play various roles in cancer biology and drug resistance, but their association with outcomes in serous epithelial ovarian cancer (EOC) is unknown. METHODS: The relationship between clinical outcomes and ABC transporter gene expression in two in...

  20. Interaction of Food Additives with Intestinal Efflux Transporters.

    Science.gov (United States)

    Sjöstedt, Noora; Deng, Feng; Rauvala, Oskari; Tepponen, Tuomas; Kidron, Heidi

    2017-11-06

    Breast cancer resistance protein (BCRP), multidrug resistance associated protein 2 (MRP2) and P-glycoprotein (P-gp) are ABC transporters that are expressed in the intestine, where they are involved in the efflux of many drugs from enterocytes back into the intestinal lumen. The inhibition of BCRP, MRP2, and P-gp can result in enhanced absorption and exposure of substrate drugs. Food additives are widely used by the food industry to improve the stability, flavor, and consistency of food products. Although they are considered safe for consumption, their interactions with intestinal transporters are poorly characterized. Therefore, in this study, selected food additives, including preservatives, colorants, and sweeteners, were studied in vitro for their inhibitory effects on intestinal ABC transporters. Among the studied compounds, several colorants were able to inhibit BCRP and MRP2, whereas P-gp was fairly insensitive to inhibition. Additionally, one sweetener was identified as a potent inhibitor of BCRP. Dose-response studies revealed that the IC 50 values of the inhibitors were lower than the estimated intestinal concentrations after the consumption of beverages containing food colorants. This suggests that there is potential for previously unrecognized transporter-mediated food additive-drug interactions.

  1. Lenalidomide modulates gene expression in human ABC-DLBCL cells by regulating IKAROS interaction with an intronic control region of SPIB.

    Science.gov (United States)

    Solomon, Lauren A; Batista, Carolina R; DeKoter, Rodney P

    2017-12-01

    Activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) is associated with a poor prognosis compared with other DLBCL types and therefore represents a top priority for developing novel therapies. Lenalidomide, an immunomodulatory drug in trials for treatment of ABC-DLBCL, targets the transcription factor IKAROS for degradation by the cereblon E3 ubiquitin ligase complex. In this study, we investigated whether the gene encoding the transcription factor SPI-B is a target of IKAROS. Using cultured ABC-DLBCL cell lines, we found that high levels of SPI-B expression conferred resistance to lenalidomide. Lenalidomide treatment of ABC-DLBCL cells resulted in downregulation of SPIB at the level of transcription. SPIB was regulated directly by IKAROS through a binding site located in the first intron of the gene. Inhibition of IKAROS binding using CRISPR/Cas9-mediated transcriptional repression downregulated endogenous SPIB transcription. Finally, ectopic expression of IKAROS protected SPIB from downregulation. These results show that the mechanism of action of lenalidomide in ABC-DLBCL cells involves downregulation of SPIB transcription by cereblon-induced degradation of IKAROS. These results have implications for the design of synthetic lethal therapy for the treatment of ABC-DLBCL. Copyright © 2017 ISEH – Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.

  2. An assessment of public involvement for the 2006 regional transportation coordination planning process in selected Texas cities

    Science.gov (United States)

    2010-12-01

    Regional mobility is cumbersome, confusing, and often a frustrating experience for many Texans. Those living in : larger urban areas have access to public transportation, while others depend on social service agencies and are : required to meet finan...

  3. Whole-genome survey of the putative ATP-binding cassette transporter family genes in Vitis vinifera.

    Science.gov (United States)

    Çakır, Birsen; Kılıçkaya, Ozan

    2013-01-01

    The ATP-binding cassette (ABC) protein superfamily constitutes one of the largest protein families known in plants. In this report, we performed a complete inventory of ABC protein genes in Vitis vinifera, the whole genome of which has been sequenced. By comparison with ABC protein members of Arabidopsis thaliana, we identified 135 putative ABC proteins with 1 or 2 NBDs in V. vinifera. Of these, 120 encode intrinsic membrane proteins, and 15 encode proteins missing TMDs. V. vinifera ABC proteins can be divided into 13 subfamilies with 79 "full-size," 41 "half-size," and 15 "soluble" putative ABC proteins. The main feature of the Vitis ABC superfamily is the presence of 2 large subfamilies, ABCG (pleiotropic drug resistance and white-brown complex homolog) and ABCC (multidrug resistance-associated protein). We identified orthologs of V. vinifera putative ABC transporters in different species. This work represents the first complete inventory of ABC transporters in V. vinifera. The identification of Vitis ABC transporters and their comparative analysis with the Arabidopsis counterparts revealed a strong conservation between the 2 species. This inventory could help elucidate the biological and physiological functions of these transporters in V. vinifera.

  4. Whole-genome survey of the putative ATP-binding cassette transporter family genes in Vitis vinifera.

    Directory of Open Access Journals (Sweden)

    Birsen Çakır

    Full Text Available The ATP-binding cassette (ABC protein superfamily constitutes one of the largest protein families known in plants. In this report, we performed a complete inventory of ABC protein genes in Vitis vinifera, the whole genome of which has been sequenced. By comparison with ABC protein members of Arabidopsis thaliana, we identified 135 putative ABC proteins with 1 or 2 NBDs in V. vinifera. Of these, 120 encode intrinsic membrane proteins, and 15 encode proteins missing TMDs. V. vinifera ABC proteins can be divided into 13 subfamilies with 79 "full-size," 41 "half-size," and 15 "soluble" putative ABC proteins. The main feature of the Vitis ABC superfamily is the presence of 2 large subfamilies, ABCG (pleiotropic drug resistance and white-brown complex homolog and ABCC (multidrug resistance-associated protein. We identified orthologs of V. vinifera putative ABC transporters in different species. This work represents the first complete inventory of ABC transporters in V. vinifera. The identification of Vitis ABC transporters and their comparative analysis with the Arabidopsis counterparts revealed a strong conservation between the 2 species. This inventory could help elucidate the biological and physiological functions of these transporters in V. vinifera.

  5. Characterization of hexose transporters in Yarrowia lipolytica reveals new groups of Sugar Porters involved in yeast growth.

    Science.gov (United States)

    Lazar, Zbigniew; Neuvéglise, Cécile; Rossignol, Tristan; Devillers, Hugo; Morin, Nicolas; Robak, Małgorzata; Nicaud, Jean-Marc; Crutz-Le Coq, Anne-Marie

    2017-03-01

    Sugar assimilation has been intensively studied in the model yeast S. cerevisiae, and for two decades, it has been clear that the homologous HXT genes, which encode a set of hexose transporters, play a central role in this process. However, in the yeast Yarrowia lipolytica, which is well-known for its biotechnological applications, sugar assimilation is only poorly understood, even though this yeast exhibits peculiar intra-strain differences in fructose uptake: some strains (e.g., W29) are known to be slow-growing in fructose while others (e.g.,