1
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Watanabe A, Hataida H, Inoue N, Kamon K, Baba K, Sasaki K, Kimura R, Sasaki H, Eura Y, Ni WF, Shibasaki Y, Waguri S, Kokame K, Shiba Y. Arf GTPase-activating proteins SMAP1 and AGFG2 regulate the size of Weibel-Palade bodies and exocytosis of von Willebrand factor. Biol Open 2021; 10:271213. [PMID: 34369554 PMCID: PMC8430232 DOI: 10.1242/bio.058789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 07/28/2021] [Indexed: 01/22/2023] Open
Abstract
Arf GTPase-Activating proteins (ArfGAPs) mediate the hydrolysis of GTP bound to ADP-ribosylation factors (Arfs), which are critical to form transport intermediates. ArfGAPs have been thought to be negative regulators of Arfs; however, accumulating evidence indicates that ArfGAPs are important for cargo sorting and promote membrane traffic. Weibel-Palade bodies (WPBs) are cigar-shaped secretory granules in endothelial cells that contain von Willebrand factor (vWF) as their main cargo. WPB biogenesis at the Golgi was reported to be regulated by Arf and their regulators, but the role of ArfGAPs has been unknown. In this study, we performed siRNA screening of ArfGAPs to investigate the role of ArfGAPs in the biogenesis of WPBs. We found two ArfGAPs, SMAP1 and AGFG2, to be involved in WPB size and vWF exocytosis, respectively. SMAP1 depletion resulted in small-sized WPBs, and the lysosomal inhibitor leupeptin recovered the size of WPBs. The results indicate that SMAP1 functions in preventing the degradation of cigar-shaped WPBs. On the other hand, AGFG2 downregulation resulted in the inhibition of vWF secretion upon Phorbol 12-myristate 13-acetate (PMA) or histamine stimulation, suggesting that AGFG2 plays a role in vWF exocytosis. Our study revealed unexpected roles of ArfGAPs in vWF transport. Summary: The Arf GTPase-activating proteins SMAP1 and AGFG2 regulate the size of Weibel-Palade bodies and exocytosis of von Willebrand factor.
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Affiliation(s)
- Asano Watanabe
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Hikari Hataida
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Naoya Inoue
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Kosuke Kamon
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Keigo Baba
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Kuniaki Sasaki
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Rika Kimura
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Honoka Sasaki
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Yuka Eura
- Department of Molecular Pathogenesis, National Cerebral and Cardiovascular Center, Osaka, 564-8565, Japan
| | - Wei-Fen Ni
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, 80201, Taiwan
| | - Yuji Shibasaki
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Satoshi Waguri
- Department of Anatomy and Histology, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Koichi Kokame
- Department of Molecular Pathogenesis, National Cerebral and Cardiovascular Center, Osaka, 564-8565, Japan
| | - Yoko Shiba
- Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
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2
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Roy NS, Jian X, Soubias O, Zhai P, Hall JR, Dagher JN, Coussens NP, Jenkins LM, Luo R, Akpan IO, Hall MD, Byrd RA, Yohe ME, Randazzo PA. Interaction of the N terminus of ADP-ribosylation factor with the PH domain of the GTPase-activating protein ASAP1 requires phosphatidylinositol 4,5-bisphosphate. J Biol Chem 2019; 294:17354-17370. [PMID: 31591270 DOI: 10.1074/jbc.ra119.009269] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 10/02/2019] [Indexed: 12/15/2022] Open
Abstract
Arf GAP with Src homology 3 domain, ankyrin repeat, and pleckstrin homology (PH) domain 1 (ASAP1) is a multidomain GTPase-activating protein (GAP) for ADP-ribosylation factor (ARF)-type GTPases. ASAP1 affects integrin adhesions, the actin cytoskeleton, and invasion and metastasis of cancer cells. ASAP1's cellular function depends on its highly-regulated and robust ARF GAP activity, requiring both the PH and the ARF GAP domains of ASAP1, and is modulated by phosphatidylinositol 4,5-bisphosphate (PIP2). The mechanistic basis of PIP2-stimulated GAP activity is incompletely understood. Here, we investigated whether PIP2 controls binding of the N-terminal extension of ARF1 to ASAP1's PH domain and thereby regulates its GAP activity. Using [Δ17]ARF1, lacking the N terminus, we found that PIP2 has little effect on ASAP1's activity. A soluble PIP2 analog, dioctanoyl-PIP2 (diC8PIP2), stimulated GAP activity on an N terminus-containing variant, [L8K]ARF1, but only marginally affected activity on [Δ17]ARF1. A peptide comprising residues 2-17 of ARF1 ([2-17]ARF1) inhibited GAP activity, and PIP2-dependently bound to a protein containing the PH domain and a 17-amino acid-long interdomain linker immediately N-terminal to the first β-strand of the PH domain. Point mutations in either the linker or the C-terminal α-helix of the PH domain decreased [2-17]ARF1 binding and GAP activity. Mutations that reduced ARF1 N-terminal binding to the PH domain also reduced the effect of ASAP1 on cellular actin remodeling. Mutations in the ARF N terminus that reduced binding also reduced GAP activity. We conclude that PIP2 regulates binding of ASAP1's PH domain to the ARF1 N terminus, which may partially regulate GAP activity.
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Affiliation(s)
- Neeladri Sekhar Roy
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Olivier Soubias
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Peng Zhai
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Jessica R Hall
- Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892
| | - Jessica N Dagher
- Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892
| | - Nathan P Coussens
- Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892
| | - Lisa M Jenkins
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Ruibai Luo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Itoro O Akpan
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Matthew D Hall
- Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892
| | - R Andrew Byrd
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Marielle E Yohe
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892 .,Pediatric Oncology Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
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3
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Arakel EC, Huranova M, Estrada AF, Rau EM, Spang A, Schwappach B. Dissection of GTPase-activating proteins reveals functional asymmetry in the COPI coat of budding yeast. J Cell Sci 2019; 132:jcs.232124. [PMID: 31331965 PMCID: PMC6737914 DOI: 10.1242/jcs.232124] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/12/2019] [Indexed: 12/11/2022] Open
Abstract
The Arf GTPase controls formation of the COPI vesicle coat. Recent structural models of COPI revealed the positioning of two Arf1 molecules in contrasting molecular environments. Each of these pockets for Arf1 is expected to also accommodate an Arf GTPase-activating protein (ArfGAP). Structural evidence and protein interactions observed between isolated domains indirectly suggest that each niche preferentially recruits one of the two ArfGAPs known to affect COPI, i.e. Gcs1/ArfGAP1 and Glo3/ArfGAP2/3, although only partial structures are available. The functional role of the unique non-catalytic domain of either ArfGAP has not been integrated into the current COPI structural model. Here, we delineate key differences in the consequences of triggering GTP hydrolysis through the activity of one versus the other ArfGAP. We demonstrate that Glo3/ArfGAP2/3 specifically triggers Arf1 GTP hydrolysis impinging on the stability of the COPI coat. We show that the Snf1 kinase complex, the yeast homologue of AMP-activated protein kinase (AMPK), phosphorylates the region of Glo3 that is crucial for this effect and, thereby, regulates its function in the COPI-vesicle cycle. Our results revise the model of ArfGAP function in the molecular context of COPI. This article has an associated First Person interview with the first author of the paper. Highlighted Article: The regulatory domain of the COPI-associated ArfGAP Glo3 can stabilize the COPI coat. GTP hydrolysis is necessary to resolve the stabilised state. This mechanism is regulated by phosphorylation.
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Affiliation(s)
- Eric C Arakel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Martina Huranova
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.,Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Alejandro F Estrada
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - E-Ming Rau
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Anne Spang
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany .,Max-Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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4
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Sztul E, Chen PW, Casanova JE, Cherfils J, Dacks JB, Lambright DG, Lee FJS, Randazzo PA, Santy LC, Schürmann A, Wilhelmi I, Yohe ME, Kahn RA. ARF GTPases and their GEFs and GAPs: concepts and challenges. Mol Biol Cell 2019; 30:1249-1271. [PMID: 31084567 PMCID: PMC6724607 DOI: 10.1091/mbc.e18-12-0820] [Citation(s) in RCA: 149] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/26/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022] Open
Abstract
Detailed structural, biochemical, cell biological, and genetic studies of any gene/protein are required to develop models of its actions in cells. Studying a protein family in the aggregate yields additional information, as one can include analyses of their coevolution, acquisition or loss of functionalities, structural pliability, and the emergence of shared or variations in molecular mechanisms. An even richer understanding of cell biology can be achieved through evaluating functionally linked protein families. In this review, we summarize current knowledge of three protein families: the ARF GTPases, the guanine nucleotide exchange factors (ARF GEFs) that activate them, and the GTPase-activating proteins (ARF GAPs) that have the ability to both propagate and terminate signaling. However, despite decades of scrutiny, our understanding of how these essential proteins function in cells remains fragmentary. We believe that the inherent complexity of ARF signaling and its regulation by GEFs and GAPs will require the concerted effort of many laboratories working together, ideally within a consortium to optimally pool information and resources. The collaborative study of these three functionally connected families (≥70 mammalian genes) will yield transformative insights into regulation of cell signaling.
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Affiliation(s)
- Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Pei-Wen Chen
- Department of Biology, Williams College, Williamstown, MA 01267
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée, CNRS and Ecole Normale Supérieure Paris-Saclay, 94235 Cachan, France
| | - Joel B. Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - David G. Lambright
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Amherst, MA 01605
| | - Fang-Jen S. Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | | | - Lorraine C. Santy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
| | - Annette Schürmann
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Ilka Wilhelmi
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Marielle E. Yohe
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-3050
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5
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Abstract
The coat protein complex I (COPI) allows the precise sorting of lipids and proteins between Golgi cisternae and retrieval from the Golgi to the ER. This essential role maintains the identity of the early secretory pathway and impinges on key cellular processes, such as protein quality control. In this Cell Science at a Glance and accompanying poster, we illustrate the different stages of COPI-coated vesicle formation and revisit decades of research in the context of recent advances in the elucidation of COPI coat structure. By calling attention to an array of questions that have remained unresolved, this review attempts to refocus the perspectives of the field.
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Affiliation(s)
- Eric C Arakel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany .,Max-Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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6
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Abstract
In eukaryotes, distinct transport vesicles functionally connect various intracellular compartments. These carriers mediate transport of membranes for the biogenesis and maintenance of organelles, secretion of cargo proteins and peptides, and uptake of cargo into the cell. Transport vesicles have distinct protein coats that assemble on a donor membrane where they can select cargo and curve the membrane to form a bud. A multitude of structural elements of coat proteins have been solved by X-ray crystallography. More recently, the architectures of the COPI and COPII coats were elucidated in context with their membrane by cryo-electron tomography. Here, we describe insights gained from the structures of these two coat lattices and discuss the resulting functional implications.
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Affiliation(s)
- Julien Béthune
- Heidelberg University Biochemistry Centre, 69120 Heidelberg, Germany; ,
| | - Felix T Wieland
- Heidelberg University Biochemistry Centre, 69120 Heidelberg, Germany; ,
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7
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Dodonova SO, Aderhold P, Kopp J, Ganeva I, Röhling S, Hagen WJH, Sinning I, Wieland F, Briggs JAG. 9Å structure of the COPI coat reveals that the Arf1 GTPase occupies two contrasting molecular environments. eLife 2017. [PMID: 28621666 PMCID: PMC5482573 DOI: 10.7554/elife.26691] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
COPI coated vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 Å resolution. We also obtained a 2.57 Å resolution crystal structure of βδ-COP. By combining these structures we built a molecular model of the coat. We additionally determined the coat structure in the presence of ArfGAP proteins that regulate coat dissociation. We found that Arf1 occupies contrasting molecular environments within the coat, leading us to hypothesize that some Arf1 molecules may regulate vesicle assembly while others regulate coat disassembly. DOI:http://dx.doi.org/10.7554/eLife.26691.001
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Affiliation(s)
- Svetlana O Dodonova
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Molecular Biology Department, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Patrick Aderhold
- Heidelberg University Biochemistry Center, Heidelberg University, Heidelberg, Germany
| | - Juergen Kopp
- Heidelberg University Biochemistry Center, Heidelberg University, Heidelberg, Germany
| | - Iva Ganeva
- Heidelberg University Biochemistry Center, Heidelberg University, Heidelberg, Germany
| | - Simone Röhling
- Heidelberg University Biochemistry Center, Heidelberg University, Heidelberg, Germany
| | - Wim J H Hagen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center, Heidelberg University, Heidelberg, Germany
| | - Felix Wieland
- Heidelberg University Biochemistry Center, Heidelberg University, Heidelberg, Germany
| | - John A G Briggs
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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8
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Chen PW, Jian X, Luo R, Randazzo PA. Simple in vitro assay of Arf GAPs and preparation of Arf proteins as substrates. Methods Cell Biol 2015; 130:69-80. [PMID: 26360029 DOI: 10.1016/bs.mcb.2015.03.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Defining the interaction of Arf GAPs with specific Arfs is important for understanding their functions in the endocytic system. Cell-based approaches have been valuable for identifying Arfs and Arf GAPs active in the endocytic compartment; however, the cell-based assays have some limitations in establishing relationships among the Arfs and ArfGAPs. Here we describe a simple in vitro assay that will provide a means for comparing Arfs as substrates and serve to complement cell-based studies.
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Affiliation(s)
- Pei-Wen Chen
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Ruibai Luo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
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9
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Abstract
Mammalian cells have many membranous organelles that require proper composition of proteins and lipids. Cargo sorting is a process required for transporting specific proteins and lipids to appropriate organelles, and if this process is disrupted, organelle function as well as cell function is disrupted. ArfGAP family proteins have been found to be critical for receptor sorting. In this review, we summarize our recent knowledge about the mechanism of cargo sorting that require function of ArfGAPs in promoting the formation of transport vesicles, and discuss the involvement of specific ArfGAPs for the sorting of a variety of receptors, such as MPR, EGFR, TfR, Glut4, TRAIL-R1/DR4, M5-muscarinic receptor, c-KIT, rhodopsin and β1-integrin. Given the importance of many of these receptors to human disease, the studies of ArfGAPs may provide novel therapeutic strategies in addition to providing mechanistic insight of receptor sorting.
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Affiliation(s)
- Yoko Shiba
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, MD20892, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, MD20892, USA
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10
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Cancino J, Luini A. Signaling Circuits on the Golgi Complex. Traffic 2012; 14:121-34. [DOI: 10.1111/tra.12022] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/12/2012] [Accepted: 10/12/2012] [Indexed: 01/21/2023]
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11
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Shiba Y, Randazzo PA. ArfGAP1 function in COPI mediated membrane traffic: currently debated models and comparison to other coat-binding ArfGAPs. Histol Histopathol 2012; 27:1143-53. [PMID: 22806901 DOI: 10.14670/hh-27.1143] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The ArfGAPs are a family of proteins containing an ArfGAP catalytic domain that induces the hydrolysis of GTP bound to the small guanine nucleotide binding-protein ADP-ribosylation factor (Arf). Functional models for Arfs, which are regulators of membrane traffic, are based on the idea that guanine nucleotide-binding proteins function as switches: Arf with GTP bound is active and binds to effector proteins; the conversion of GTP to GDP inactivates Arf. The cellular activities of ArfGAPs have been examined primarily as regulatory proteins that inactivate Arf; however, Arf function in membrane traffic does not strictly adhere to the concept of a simple switch, adding complexity to models explaining the role of ArfGAPs. Here, we review the literature addressing the function Arf and ArfGAP1 in COPI mediated transport, focusing on two critical and integrated functions of membrane traffic, cargo sorting and vesicle coat polymerization. We briefly discuss other ArfGAPs that may have similar function in Arf-dependent membrane traffic outside the ER-Golgi.
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Affiliation(s)
- Yoko Shiba
- National Cancer Institute, Laboratory of Cellular and Molecular Biology, Bethesda, MD 20892, USA
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12
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Cottam NP, Ungar D. Retrograde vesicle transport in the Golgi. PROTOPLASMA 2012; 249:943-55. [PMID: 22160157 DOI: 10.1007/s00709-011-0361-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 11/29/2011] [Indexed: 05/23/2023]
Abstract
The Golgi apparatus is the central sorting and biosynthesis hub of the secretory pathway, and uses vesicle transport for the recycling of its resident enzymes. This system must operate with high fidelity and efficiency for the correct modification of secretory glycoconjugates. In this review, we discuss recent advances on how coats, tethers, Rabs and SNAREs cooperate at the Golgi to achieve vesicle transport. We cover the well understood vesicle formation process orchestrated by the COPI coat, and the comprehensively documented fusion process governed by a set of Golgi localised SNAREs. Much less clear are the steps in-between formation and fusion of vesicles, and we therefore provide a much needed update of the latest findings about vesicle tethering. The interplay between Rab GTPases, golgin family coiled-coil tethers and the conserved oligomeric Golgi (COG) complex at the Golgi are thoroughly evaluated.
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Affiliation(s)
- Nathanael P Cottam
- Department of Biology (Area 9), University of York, Heslington, York, YO10 5DD, UK
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13
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Pevzner I, Strating J, Lifshitz L, Parnis A, Glaser F, Herrmann A, Brügger B, Wieland F, Cassel D. Distinct role of subcomplexes of the COPI coat in the regulation of ArfGAP2 activity. Traffic 2012; 13:849-56. [PMID: 22375848 DOI: 10.1111/j.1600-0854.2012.01349.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 02/27/2012] [Accepted: 02/29/2012] [Indexed: 11/29/2022]
Abstract
COPI vesicles serve for transport of proteins and membrane lipids in the early secretory pathway. Their coat protein (coatomer) is a heptameric complex that is recruited to the Golgi by the small GTPase Arf1. Although recruited en bloc, coatomer can be viewed as a stable assembly of an adaptin-like tetrameric subcomplex (CM4) and a trimeric 'cage' subcomplex (CM3). Following recruitment, coatomer stimulates ArfGAP-dependent GTP hydrolysis on Arf1. Here, we employed recombinant coatomer subcomplexes to study the role of coatomer components in the regulation of ArfGAP2, an ArfGAP whose activity is strictly coatomer-dependent. Within CM4, we define a novel hydrophobic pocket for ArfGAP2 interaction on the appendage domain of γ₁-COP. The CM4 subcomplex (but not CM3) is recruited to membranes through Arf1 and can subsequently recruit ArfGAP2. Neither CM3 nor CM4 in itself is effective in stimulating ArfGAP2 activity, but stimulation is regained when both subcomplexes are present. Our findings point to a distinct role of each of the two coatomer subcomplexes in the regulation of ArfGAP2-dependent GTP hydrolysis on Arf1, where the CM4 subcomplex functions in GAP recruitment, while, similarly to the COPII system, the cage-like CM3 subcomplex stimulates the catalytic reaction.
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Affiliation(s)
- Irit Pevzner
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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14
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Luo R, Akpan IO, Hayashi R, Sramko M, Barr V, Shiba Y, Randazzo PA. GTP-binding protein-like domain of AGAP1 is protein binding site that allosterically regulates ArfGAP protein catalytic activity. J Biol Chem 2012; 287:17176-17185. [PMID: 22453919 DOI: 10.1074/jbc.m111.334458] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AGAPs are a subtype of Arf GTPase-activating proteins (GAPs) with 11 members in humans. In addition to the Arf GAP domain, the proteins contain a G-protein-like domain (GLD) with homology to Ras superfamily proteins and a PH domain. AGAPs bind to clathrin adaptors, function in post Golgi membrane traffic, and have been implicated in glioblastoma. The regulation of AGAPs is largely unexplored. Other enzymes containing GTP binding domains are regulated by nucleotide binding. However, nucleotide binding to AGAPs has not been detected. Here, we found that neither nucleotides nor deleting the GLD of AGAP1 affected catalysis, which led us to hypothesize that the GLD is a protein binding site that regulates GAP activity. Two-hybrid screens identified RhoA, Rac1, and Cdc42 as potential binding partners. Coimmunoprecipitation confirmed that AGAP1 and AGAP2 can bind to RhoA. Binding was mediated by the C terminus of RhoA and was independent of nucleotide. RhoA and the C-terminal peptide from RhoA increased GAP activity specifically for the substrate Arf1. In contrast, a C-terminal peptide from Cdc42 neither bound nor activated AGAP1. Based on these results, we propose that AGAPs are allosterically regulated through protein binding to the GLD domain.
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Affiliation(s)
- Ruibai Luo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892
| | - Itoro O Akpan
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892
| | - Ryo Hayashi
- Department of Chemistry, Faculty of Science and Engineering, Saga University, Honjo, Saga 840-8502, Japan
| | - Marek Sramko
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892
| | - Valarie Barr
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892
| | - Yoko Shiba
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892.
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15
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Abstract
Protein traffic is necessary to maintain homeostasis in all eukaryotic organisms. All newly synthesized secretory proteins destined to the secretory and endolysosmal systems are transported from the endoplasmic reticulum to the Golgi before delivery to their final destinations. Here, we describe the COPII and COPI coating machineries that generate carrier vesicles and the tethers and SNAREs that mediate COPII and COPI vesicle fusion at the ER-Golgi interface.
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Affiliation(s)
- Tomasz Szul
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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16
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Meierhofer T, Eberhardt M, Spoerner M. Conformational states of ADP ribosylation factor 1 complexed with different guanosine triphosphates as studied by 31P NMR spectroscopy. Biochemistry 2011; 50:6316-27. [PMID: 21702511 DOI: 10.1021/bi101573j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Guanine nucleotide binding proteins (GNB-proteins) play an essential role in cellular signaling, acting as molecular switches, cycling between the inactive, GDP-bound form and the active, GTP-bound form. It has been shown that conformational equilibria also exist within the active form of GNB-proteins between conformational states with different functional properties. Here we present (31)P NMR data on ADP ribosylation factor 1 (Arf1), a GNB-protein involved in Golgi traffic, promoting the coating of secretory vesicles. To investigate conformational equilibria in active Arf1, the wild type and switch I mutants complexed with GTP and a variety of commonly used GTP analogues, namely, GppCH(2)p, GppNHp, and GTPγS, were analyzed. To gain deeper insight into the conformational state of active Arf1, we titrated with Cu(2+)-cyclen and GdmCl and formed the complex with the Sec7 domain of nucleotide exchange factor ARNO and an effector GAT domain. In contrast to the related proteins Ras, Ral, Cdc42, and Ran, from (31)P NMR spectroscopic view, Arf1 exists predominantly in a single conformation independent of the GTP analogue used. This state seems to correspond to the so-called state 2(T) conformation, according to Ras nomenclature, which is interacting with the effector domain. The exchange of the highly conserved threonine in position 48 with alanine led to a shift of the equilibrium toward a conformational state with typical properties obtained for state 1(T) in Ras, such as interaction with guanine nucleotide exchange factors, a lower affinity for nucleoside triphosphates, and greater sensitivity to chaotropic agents. In active Arf1(wt), the effector interacting conformation is strongly favored. These intrinsic conformational equilibria of active GNB-proteins could be a fine-tuning mechanism of regulation and thereby an interesting target for the modulation of protein activity.
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Affiliation(s)
- Tanja Meierhofer
- University of Regensburg, Institute of Biophysics and Physical Biochemistry, Universitätsstrasse 31, D-93053 Regensburg, Germany
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17
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Shiba Y, Luo R, Hinshaw JE, Szul T, Hayashi R, Sztul E, Nagashima K, Baxa U, Randazzo PA. ArfGAP1 promotes COPI vesicle formation by facilitating coatomer polymerization. CELLULAR LOGISTICS 2011; 1:139-154. [PMID: 22279613 PMCID: PMC3265926 DOI: 10.4161/cl.1.4.18896] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 11/21/2011] [Accepted: 11/29/2011] [Indexed: 12/31/2022]
Abstract
The role of ArfGAP1 in COPI vesicle biogenesis has been controversial. In work using isolated Golgi membranes, ArfGAP1 was found to promote COPI vesicle formation. In contrast, in studies using large unilamellar vesicles (LUVs) as model membranes, ArfGAP1 functioned as an uncoating factor inhibiting COPI vesicle formation. We set out to discriminate between these models. First, we reexamined the effect of ArfGAP1 on LUVs. We found that ArfGAP1 increased the efficiency of coatomer-induced deformation of LUVs. Second, ArfGAP1 and peptides from cargo facilitated self-assembly of coatomer into spherical structures in the absence of membranes, reminiscent of clathrin self-assembly. Third, in vivo, ArfGAP1 overexpression induced the accumulation of vesicles and allowed normal trafficking of a COPI cargo. Taken together, these data support the model in which ArfGAP1 promotes COPI vesicle formation and membrane traffic and identify a function for ArfGAP1 in the assembly of coatomer into COPI.
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Affiliation(s)
- Yoko Shiba
- Laboratory of Cellular and Molecular Biology; National Cancer Institute, Bethesda, MD USA
| | - Ruibai Luo
- Laboratory of Cellular and Molecular Biology; National Cancer Institute, Bethesda, MD USA
| | - Jenny E Hinshaw
- National Institute of Diabetes and Digestive and Kidney Disease; National Institutes of Health; Bethesda, MD USA
| | - Tomasz Szul
- Department of Cell Biology; The University of Alabama at Birmingham; Birmingham, AL USA
| | - Ryo Hayashi
- Laboratory of Cell Biology; National Cancer Institute; Bethesda, MD USA
| | - Elizabeth Sztul
- Department of Cell Biology; The University of Alabama at Birmingham; Birmingham, AL USA
| | - Kunio Nagashima
- Electron Microscopy Laboratory, ATP, SAIC-Frederick, Center for Cancer Research, National Cancer Institute; Frederick, MD USA
| | - Ulrich Baxa
- Electron Microscopy Laboratory, ATP, SAIC-Frederick, Center for Cancer Research, National Cancer Institute; Frederick, MD USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology; National Cancer Institute, Bethesda, MD USA
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18
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19
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East MP, Kahn RA. Models for the functions of Arf GAPs. Semin Cell Dev Biol 2010; 22:3-9. [PMID: 20637885 DOI: 10.1016/j.semcdb.2010.07.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 07/02/2010] [Accepted: 07/07/2010] [Indexed: 11/27/2022]
Abstract
Arf GAPs (ADP-ribosylation factor GTPase-activating proteins) are essential components of Arf (ADP-ribosylation factor) signaling pathways. Arf GAPs stimulate the hydrolysis of GTP to GDP to transition Arf from the active, GTP bound, state to the inactive, GDP bound, state. Based on this activity, Arf GAPs were initially proposed to function primarily or exclusively as terminators of Arf signaling. Further studies of Arf GAPs have revealed that they also function as effectors of Arf signaling in at least a few steps or processes in which Arfs are not directly involved. In this review we discuss the non-canonical functions of Arf GAPs and address several key questions in the field, including: whether (1) Arf GAPs are terminators or effectors of Arf signaling, (2) Arf GAPs positively or negatively regulate COPI assembly, (3) Arf GAPs are involved in vesicle fission, and (4) Arf GAPs regulate vesicle uncoating.
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Affiliation(s)
- Michael P East
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-3050, USA.
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20
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Liu Y, Kahn RA, Prestegard JH. Dynamic structure of membrane-anchored Arf*GTP. Nat Struct Mol Biol 2010; 17:876-81. [PMID: 20601958 PMCID: PMC2921649 DOI: 10.1038/nsmb.1853] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 04/13/2010] [Indexed: 11/11/2022]
Abstract
Arfs (ADP ribosylation factors) are N-myristoylated GTP/GDP switch proteins playing key regulatory roles in vesicle transport in eukaryotic cells. ARFs execute their roles by anchoring to membrane surfaces where they interact with other proteins to initiate budding and maturation of transport vesicles. However, existing structures of Arf•GTP are limited to non-myristoylated and truncated forms with impaired membrane binding. We report a high resolution NMR structure for full-length myristoylated yeast (Saccharomyces cerevisiae) Arf1 in complex with a membrane mimic. The two domain structure, in which the myristoylated N-terminal helix is separated from the C-terminal domain by a flexible linker, suggests a level of adaptability in binding modes for the myriad of proteins with which Arf interacts, and allows predictions of specific lipid binding sites on some of these proteins.
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Affiliation(s)
- Yizhou Liu
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
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21
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Spang A, Shiba Y, Randazzo PA. Arf GAPs: gatekeepers of vesicle generation. FEBS Lett 2010; 584:2646-51. [PMID: 20394747 DOI: 10.1016/j.febslet.2010.04.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 03/26/2010] [Accepted: 04/03/2010] [Indexed: 11/17/2022]
Abstract
Arf GAP proteins are a versatile and diverse group of proteins. They control the activity of the GTP-binding proteins of the ARF family by inducing the hydrolysis of GTP that is bound to Arf proteins. The best-studied role of Arf GAPs is in intracellular traffic. In this review, we will focus mainly on the Arf GAPs that play a role in vesicle formation, Arf GAP1, Arf GAP2 and Arf GAP3 and their yeast homologues, Gcs1p and Glo3p. We discuss the roles of Arf GAPs as regulators and effectors for Arf GTP-binding proteins.
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Affiliation(s)
- Anne Spang
- University of Basel, Growth and Development, Biozentrum, Switzerland.
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22
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Chen PW, Randazzo PA, Parent CA. ACAP-A/B are ArfGAP homologs in dictyostelium involved in sporulation but not in chemotaxis. PLoS One 2010; 5:e8624. [PMID: 20062541 PMCID: PMC2797641 DOI: 10.1371/journal.pone.0008624] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 12/14/2009] [Indexed: 11/29/2022] Open
Abstract
Arfs and Arf GTPase-activating proteins (ArfGAPs) are regulators of membrane trafficking and actin dynamics in mammalian cells. In this study, we identified a primordial Arf, ArfA, and two ArfGAPs (ACAP-A/B) containing BAR, PH, ArfGAP and Ankyrin repeat domains in the eukaryote Dictyostelium discoideum. In vitro, ArfA has similar nucleotide binding properties as mammalian Arfs and, with GTP bound, is a substrate for ACAP-A and B. We also investigated the physiological functions of ACAP-A/B by characterizing cells lacking both ACAP-A and B. Although ACAP-A/B knockout cells showed no defects in cell growth, migration or chemotaxis, they exhibited abnormal actin protrusions and ∼50% reduction in spore yield. We conclude that while ACAP-A/B have a conserved biochemical mechanism and effect on actin organization, their role in migration is not conserved. The absence of an effect on Dictyostelium migration may be due to a specific requirement for ACAPs in mesenchymal migration, which is observed in epithelial cancer cells where most studies of mammalian ArfGAPs were performed.
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Affiliation(s)
- Pei-Wen Chen
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Paul A. Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, Maryland, United States of America
- * E-mail:
| | - Carole A. Parent
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, Maryland, United States of America
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23
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Beck R, Ravet M, Wieland F, Cassel D. The COPI system: Molecular mechanisms and function. FEBS Lett 2009; 583:2701-9. [DOI: 10.1016/j.febslet.2009.07.032] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/07/2009] [Accepted: 07/13/2009] [Indexed: 02/03/2023]
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