1
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Mohr I, Mirzaiebadizi A, Sanyal SK, Chuenban P, Ahmadian MR, Ivanov R, Bauer P. Characterization of the small Arabidopsis thaliana GTPase and ADP-ribosylation factor-like 2 protein TITAN 5. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.27.538563. [PMID: 37162876 PMCID: PMC10168340 DOI: 10.1101/2023.04.27.538563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Small GTPases function by conformational switching ability between GDP- and GTP-bound states in rapid cell signaling events. The ADP-ribosylation factor (ARF) family is involved in vesicle trafficking. Though evolutionarily well conserved, little is known about ARF and ARF-like GTPases in plants. Here, we characterized biochemical properties and cellular localization of the essential small ARF-like GTPase TITAN 5/HALLIMASCH/ARL2/ARLC1 (hereafter termed TTN5) from Arabidopsis thaliana. Two TTN5 variants were included in the study with point mutations at conserved residues, suspected to be functional for nucleotide exchange and GTP hydrolysis, TTN5T30N and TTN5Q70L. We found that TTN5 had a very rapid intrinsic nucleotide exchange capacity with a conserved nucleotide switching mechanism. TTN5 acted as a non-classical small GTPase with a remarkably low GTP hydrolysis activity, suggesting it is likely present in GTP-loaded active form in the cell. We analyzed signals from yellow fluorescent protein (YFP)-tagged TTN5 and from in situ immunolocalization of hemagglutine-tagged HA3-TTN5 in Arabidopsis seedlings and in a transient expression system. Together with colocalization using endomembrane markers and pharmacological treatments the microscopic analysis suggests that TTN5 can be present at the plasma membrane and dynamically associated with membranes of vesicles, Golgi stacks and multivesicular bodies. While the TTN5Q70L variant showed similar GTPase activities and localization behavior as wild-type TTN5, the TTN5T30N mutant differed in some aspects. Hence, the unusual capacity of rapid nucleotide exchange activity of TTN5 is linked with cell membrane dynamics, likely associated with vesicle transport pathways in the endomembrane system.
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Affiliation(s)
- Inga Mohr
- Institute of Botany, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Amin Mirzaiebadizi
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Sibaji K Sanyal
- Institute of Botany, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Pichaporn Chuenban
- Institute of Botany, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Mohammad R Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Rumen Ivanov
- Institute of Botany, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Petra Bauer
- Institute of Botany, Heinrich Heine University, 40225 Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences, Heinrich Heine University, 40225 Düsseldorf, Germany
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2
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Schlienger S, Yam PT, Balekoglu N, Ducuing H, Michaud JF, Makihara S, Kramer DK, Chen B, Fasano A, Berardelli A, Hamdan FF, Rouleau GA, Srour M, Charron F. Genetics of mirror movements identifies a multifunctional complex required for Netrin-1 guidance and lateralization of motor control. SCIENCE ADVANCES 2023; 9:eadd5501. [PMID: 37172092 PMCID: PMC10181192 DOI: 10.1126/sciadv.add5501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 04/06/2023] [Indexed: 05/14/2023]
Abstract
Mirror movements (MM) disorder is characterized by involuntary movements on one side of the body that mirror intentional movements on the opposite side. We performed genetic characterization of a family with autosomal dominant MM and identified ARHGEF7, a RhoGEF, as a candidate MM gene. We found that Arhgef7 and its partner Git1 bind directly to Dcc. Dcc is the receptor for Netrin-1, an axon guidance cue that attracts commissural axons to the midline, promoting the midline crossing of axon tracts. We show that Arhgef7 and Git1 are required for Netrin-1-mediated axon guidance and act as a multifunctional effector complex. Arhgef7/Git1 activates Rac1 and Cdc42 and inhibits Arf1 downstream of Netrin-1. Furthermore, Arhgef7/Git1, via Arf1, mediates the Netrin-1-induced increase in cell surface Dcc. Mice heterozygous for Arhgef7 have defects in commissural axon trajectories and increased symmetrical paw placements during skilled walking, a MM-like phenotype. Thus, we have delineated how ARHGEF7 mutation causes MM.
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Affiliation(s)
- Sabrina Schlienger
- Montreal Clinical Research Institute (IRCM), 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
- Department of Anatomy and Cell Biology, Division of Experimental Medicine, McGill University, Montreal, QC H3A 0G4, Canada
| | - Patricia T. Yam
- Montreal Clinical Research Institute (IRCM), 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
| | - Nursen Balekoglu
- Montreal Clinical Research Institute (IRCM), 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B4, Canada
| | - Hugo Ducuing
- Montreal Clinical Research Institute (IRCM), 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
| | - Jean-Francois Michaud
- Montreal Clinical Research Institute (IRCM), 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
| | - Shirin Makihara
- Montreal Clinical Research Institute (IRCM), 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B4, Canada
| | - Daniel K. Kramer
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Alfonso Fasano
- Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, ON, Canada
- Division of Neurology, University of Toronto, Toronto, ON, Canada
- Krembil Brain Institute, Toronto, ON, Canada
| | - Alfredo Berardelli
- IRCCS Neuromed, Pozzilli (IS), Italy
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Fadi F. Hamdan
- Division of Medical Genetics, Department of Pediatrics, CHU Sainte-Justine and University of Montreal, Montreal, QC H3T1C5, Canada
| | - Guy A. Rouleau
- Division of Medical Genetics, Department of Pediatrics, CHU Sainte-Justine and University of Montreal, Montreal, QC H3T1C5, Canada
- Department of Human Genetics, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Myriam Srour
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
- Department of Pediatrics, Division of Pediatric Neurology, McGill University, Montreal, QC H4A 3J1, Canada
- McGill University Health Center Research Institute, Montreal, QC H4A 3J1, Canada
| | - Frederic Charron
- Montreal Clinical Research Institute (IRCM), 110 Pine Avenue West, Montreal, QC H2W 1R7, Canada
- Department of Anatomy and Cell Biology, Division of Experimental Medicine, McGill University, Montreal, QC H3A 0G4, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B4, Canada
- Department of Medicine, University of Montreal, Montreal, QC H3T 1J4, Canada
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3
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Ishida M, Otero MG, Freeman C, Sánchez-Lara PA, Guardia CM, Pierson TM, Bonifacino JS. A neurodevelopmental disorder associated with an activating de novo missense variant in ARF1. Hum Mol Genet 2023; 32:1162-1174. [PMID: 36345169 PMCID: PMC10026249 DOI: 10.1093/hmg/ddac279] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/31/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
ADP-ribosylation factor 1 (ARF1) is a small GTPase that regulates membrane traffic at the Golgi apparatus and endosomes through recruitment of several coat proteins and lipid-modifying enzymes. Here, we report a pediatric patient with an ARF1-related disorder because of a monoallelic de novo missense variant (c.296 G > A; p.R99H) in the ARF1 gene, associated with developmental delay, hypotonia, intellectual disability and motor stereotypies. Neuroimaging revealed a hypoplastic corpus callosum and subcortical white matter abnormalities. Notably, this patient did not exhibit periventricular heterotopias previously observed in other patients with ARF1 variants (including p.R99H). Functional analysis of the R99H-ARF1 variant protein revealed that it was expressed at normal levels and properly localized to the Golgi apparatus; however, the expression of this variant caused swelling of the Golgi apparatus, increased the recruitment of coat proteins such as coat protein complex I, adaptor protein complex 1 and GGA3 and altered the morphology of recycling endosomes. In addition, we observed that the expression of R99H-ARF1 prevented dispersal of the Golgi apparatus by the ARF1-inhibitor brefeldin A. Finally, protein interaction analyses showed that R99H-ARF1 bound more tightly to the ARF1-effector GGA3 relative to wild-type ARF1. These properties were similar to those of the well-characterized constitutively active Q71L-ARF1 mutant, indicating that the pathogenetic mechanism of the R99H-ARF1 variant involves constitutive activation with resultant Golgi and endosomal alterations. The absence of periventricular nodular heterotopias in this R99H-ARF1 subject also indicates that this finding may not be a consistent phenotypic expression of all ARF1-related disorders.
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Affiliation(s)
- Morié Ishida
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - María G Otero
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Christina Freeman
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Pedro A Sánchez-Lara
- Division of Medical Genetics, Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Carlos M Guardia
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27703, USA
| | - Tyler Mark Pierson
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Division of Pediatric Neurology, Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Center for the Undiagnosed Patient, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Juan S Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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4
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Fasano G, Muto V, Radio FC, Venditti M, Mosaddeghzadeh N, Coppola S, Paradisi G, Zara E, Bazgir F, Ziegler A, Chillemi G, Bertuccini L, Tinari A, Vetro A, Pantaleoni F, Pizzi S, Conti LA, Petrini S, Bruselles A, Prandi IG, Mancini C, Chandramouli B, Barth M, Bris C, Milani D, Selicorni A, Macchiaiolo M, Gonfiantini MV, Bartuli A, Mariani R, Curry CJ, Guerrini R, Slavotinek A, Iascone M, Dallapiccola B, Ahmadian MR, Lauri A, Tartaglia M. Dominant ARF3 variants disrupt Golgi integrity and cause a neurodevelopmental disorder recapitulated in zebrafish. Nat Commun 2022; 13:6841. [PMID: 36369169 PMCID: PMC9652361 DOI: 10.1038/s41467-022-34354-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/24/2022] [Indexed: 11/13/2022] Open
Abstract
Vesicle biogenesis, trafficking and signaling via Endoplasmic reticulum-Golgi network support essential developmental processes and their disruption lead to neurodevelopmental disorders and neurodegeneration. We report that de novo missense variants in ARF3, encoding a small GTPase regulating Golgi dynamics, cause a developmental disease in humans impairing nervous system and skeletal formation. Microcephaly-associated ARF3 variants affect residues within the guanine nucleotide binding pocket and variably perturb protein stability and GTP/GDP binding. Functional analysis demonstrates variably disruptive consequences of ARF3 variants on Golgi morphology, vesicles assembly and trafficking. Disease modeling in zebrafish validates further the dominant behavior of the mutants and their differential impact on brain and body plan formation, recapitulating the variable disease expression. In-depth in vivo analyses traces back impaired neural precursors' proliferation and planar cell polarity-dependent cell movements as the earliest detectable effects. Our findings document a key role of ARF3 in Golgi function and demonstrate its pleiotropic impact on development.
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Affiliation(s)
- Giulia Fasano
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Valentina Muto
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Francesca Clementina Radio
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Martina Venditti
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Niloufar Mosaddeghzadeh
- grid.411327.20000 0001 2176 9917Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Simona Coppola
- grid.416651.10000 0000 9120 6856National Center for Rare Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Graziamaria Paradisi
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy ,grid.12597.380000 0001 2298 9743Department for Innovation in Biological Agro-food and Forest systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy
| | - Erika Zara
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy ,grid.7841.aDepartment of Biology and Biotechnology “Charles Darwin”, Università “Sapienza”, Rome, 00185 Italy
| | - Farhad Bazgir
- grid.411327.20000 0001 2176 9917Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Alban Ziegler
- grid.7252.20000 0001 2248 3363UFR Santé de l’Université d’Angers, INSERM U1083, CNRS UMR6015, MITOVASC, SFR ICAT, F-49000 Angers, France ,grid.411147.60000 0004 0472 0283Département de Génétique, CHU d’Angers, 49000 Angers, France
| | - Giovanni Chillemi
- grid.12597.380000 0001 2298 9743Department for Innovation in Biological Agro-food and Forest systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy ,grid.5326.20000 0001 1940 4177Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Centro Nazionale delle Ricerche, 70126 Bari, Italy
| | - Lucia Bertuccini
- grid.416651.10000 0000 9120 6856Servizio grandi strumentazioni e core facilities, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Antonella Tinari
- grid.416651.10000 0000 9120 6856Centro di riferimento per la medicina di genere, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Annalisa Vetro
- grid.8404.80000 0004 1757 2304Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children’s Hospital, University of Florence, 50139 Florence, Italy
| | - Francesca Pantaleoni
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Simone Pizzi
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Libenzio Adrian Conti
- grid.414603.4Confocal Microscopy Core Facility, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Stefania Petrini
- grid.414603.4Confocal Microscopy Core Facility, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Alessandro Bruselles
- grid.416651.10000 0000 9120 6856Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Ingrid Guarnetti Prandi
- grid.12597.380000 0001 2298 9743Department for Innovation in Biological Agro-food and Forest systems (DIBAF), University of Tuscia, 01100 Viterbo, Italy
| | - Cecilia Mancini
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Balasubramanian Chandramouli
- grid.431603.30000 0004 1757 1950Super Computing Applications and Innovation, CINECA, 40033 Casalecchio di Reno, Italy
| | - Magalie Barth
- grid.411147.60000 0004 0472 0283Département de Génétique, CHU d’Angers, 49000 Angers, France
| | - Céline Bris
- grid.7252.20000 0001 2248 3363UFR Santé de l’Université d’Angers, INSERM U1083, CNRS UMR6015, MITOVASC, SFR ICAT, F-49000 Angers, France ,grid.411147.60000 0004 0472 0283Département de Génétique, CHU d’Angers, 49000 Angers, France
| | - Donatella Milani
- grid.414818.00000 0004 1757 8749Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Angelo Selicorni
- grid.512106.1Mariani Center for Fragile Children Pediatric Unit, Azienda Socio Sanitaria Territoriale Lariana, 22100 Como, Italy
| | - Marina Macchiaiolo
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Michaela V. Gonfiantini
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Andrea Bartuli
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Riccardo Mariani
- grid.414603.4Department of Laboratories Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Cynthia J. Curry
- grid.266102.10000 0001 2297 6811Genetic Medicine, Dept of Pediatrics, University of California San Francisco, Ca, Fresno, Ca, San Francisco, CA 94143 USA
| | - Renzo Guerrini
- grid.8404.80000 0004 1757 2304Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children’s Hospital, University of Florence, 50139 Florence, Italy
| | - Anne Slavotinek
- grid.266102.10000 0001 2297 6811Genetic Medicine, Dept of Pediatrics, University of California San Francisco, Ca, Fresno, Ca, San Francisco, CA 94143 USA
| | - Maria Iascone
- grid.460094.f0000 0004 1757 8431Medical Genetics, ASST Papa Giovanni XXIII, 24127 Bergamo, Italy
| | - Bruno Dallapiccola
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Mohammad Reza Ahmadian
- grid.411327.20000 0001 2176 9917Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Antonella Lauri
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Marco Tartaglia
- grid.414603.4Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
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5
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Jung J, Khan MM, Landry J, Halavatyi A, Machado P, Reiss M, Pepperkok R. Regulation of the COPII secretory machinery via focal adhesions and extracellular matrix signaling. J Cell Biol 2022; 221:213351. [PMID: 35829701 PMCID: PMC9284426 DOI: 10.1083/jcb.202110081] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 05/10/2022] [Accepted: 06/24/2022] [Indexed: 12/19/2022] Open
Abstract
Proteins that enter the secretory pathway are transported from their place of synthesis in the endoplasmic reticulum to the Golgi complex by COPII-coated carriers. The networks of proteins that regulate these components in response to extracellular cues have remained largely elusive. Using high-throughput microscopy, we comprehensively screened 378 cytoskeleton-associated and related proteins for their functional interaction with the coat protein complex II (COPII) components SEC23A and SEC23B. Among these, we identified a group of proteins associated with focal adhesions (FERMT2, MACF1, MAPK8IP2, NGEF, PIK3CA, and ROCK1) that led to the downregulation of SEC23A when depleted by siRNA. Changes in focal adhesions induced by plating cells on ECM also led to the downregulation of SEC23A and decreases in VSVG transport from ER to Golgi. Both the expression of SEC23A and the transport defect could be rescued by treatment with a focal adhesion kinase inhibitor. Altogether, our results identify a network of cytoskeleton-associated proteins connecting focal adhesions and ECM-related signaling with the gene expression of the COPII secretory machinery and trafficking.
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Affiliation(s)
- Juan Jung
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Muzamil Majid Khan
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Translational Lung Research Center Heidelberg, German Center for Lung Research, Heidelberg, Germany
| | - Jonathan Landry
- Core Facilities Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Aliaksandr Halavatyi
- Core Facilities Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Pedro Machado
- Core Facilities Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Miriam Reiss
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Rainer Pepperkok
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Core Facilities Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Translational Lung Research Center Heidelberg, German Center for Lung Research, Heidelberg, Germany
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6
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Saito-Nakano Y, Makiuchi T, Tochikura M, Gilchrist CA, Petri WA, Nozaki T. ArfX2 GTPase Regulates Trafficking From the Trans-Golgi to Lysosomes and Is Necessary for Liver Abscess Formation in the Protozoan Parasite Entamoeba histolytica. Front Cell Infect Microbiol 2022; 11:794152. [PMID: 34976870 PMCID: PMC8719317 DOI: 10.3389/fcimb.2021.794152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/24/2021] [Indexed: 02/03/2023] Open
Abstract
Entamoeba histolytica is the causative agent of amoebic dysentery and liver abscess in humans. The parasitic lifestyle and the virulence of the protist require elaborate biological processes, including vesicular traffic and stress management against a variety of reactive oxygen and nitrogen species produced by the host immune response. Although the mechanisms for intracellular traffic of representative virulence factors have been investigated at molecular levels, it remains poorly understood whether and how intracellular traffic is involved in the defense against reactive oxygen and nitrogen species. Here, we demonstrate that EhArfX2, one of the Arf family of GTPases known to be involved in the regulation of vesicular traffic, was identified by comparative transcriptomic analysis of two isogenic strains: an animal-passaged highly virulent HM-1:IMSS Cl6 and in vitro maintained attenuated avirulent strain. EhArfX2 was identified as one of the most highly upregulated genes in the highly virulent strain. EhArfX2 was localized to small vesicle-like structures and largely colocalized with the marker for the trans-Golgi network SNARE, EhYkt6, but neither with the endoplasmic reticulum (ER)-resident chaperon, EhBip, nor the cis-Golgi SNARE, EhSed5, and Golgi-luminal galactosyl transferase, EhGalT. Expression of the dominant-active mutant form of EhArfX2 caused an increase in the number of lysosomes, while expression of the dominant-negative mutant led to a defect in lysosome formation and cysteine protease transport to lysosomes. Expression of the dominant-negative mutant in the virulent E. histolytica strain caused a reduction of the size of liver abscesses in a hamster model. This defect in liver abscess formation was likely at least partially attributed to reduced resistance to nitrosative, but not oxidative stress in vitro. These results showed that the EhArfX2-mediated traffic is necessary for the nitrosative stress response and virulence in the host.
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Affiliation(s)
- Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Takashi Makiuchi
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Mami Tochikura
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Carol A Gilchrist
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - William A Petri
- Department of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Tomoyoshi Nozaki
- Graduate School of Medicine, The University of Tokyo, Bunkyo, Tokyo, Japan
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7
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Pennauer M, Buczak K, Prescianotto-Baschong C, Spiess M. Shared and specific functions of Arfs 1-5 at the Golgi revealed by systematic knockouts. J Cell Biol 2022; 221:212750. [PMID: 34749397 PMCID: PMC8579194 DOI: 10.1083/jcb.202106100] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/14/2021] [Accepted: 10/04/2021] [Indexed: 12/22/2022] Open
Abstract
ADP-ribosylation factors (Arfs) are small GTPases regulating membrane traffic in the secretory pathway. They are closely related and appear to have overlapping functions, regulators, and effectors. The functional specificity of individual Arfs and the extent of redundancy are still largely unknown. We addressed these questions by CRISPR/Cas9-mediated genomic deletion of the human class I (Arf1/3) and class II (Arf4/5) Arfs, either individually or in combination. Most knockout cell lines were viable with slight growth defects only when lacking Arf1 or Arf4. However, Arf1+4 and Arf4+5 could not be deleted simultaneously. Class I Arfs are nonessential, and Arf4 alone is sufficient for viability. Upon Arf1 deletion, the Golgi was enlarged, and recruitment of vesicle coats decreased, confirming a major role of Arf1 in vesicle formation at the Golgi. Knockout of Arf4 caused secretion of ER-resident proteins, indicating specific defects in coatomer-dependent ER protein retrieval by KDEL receptors. The knockout cell lines will be useful tools to study other Arf-dependent processes.
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8
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Pothukuchi P, Agliarulo I, Pirozzi M, Rizzo R, Russo D, Turacchio G, Nüchel J, Yang JS, Gehin C, Capolupo L, Hernandez-Corbacho MJ, Biswas A, Vanacore G, Dathan N, Nitta T, Henklein P, Thattai M, Inokuchi JI, Hsu VW, Plomann M, Obeid LM, Hannun YA, Luini A, D'Angelo G, Parashuraman S. GRASP55 regulates intra-Golgi localization of glycosylation enzymes to control glycosphingolipid biosynthesis. EMBO J 2021; 40:e107766. [PMID: 34516001 PMCID: PMC8521277 DOI: 10.15252/embj.2021107766] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 07/26/2021] [Accepted: 08/06/2021] [Indexed: 12/24/2022] Open
Abstract
The Golgi apparatus, the main glycosylation station of the cell, consists of a stack of discontinuous cisternae. Glycosylation enzymes are usually concentrated in one or two specific cisternae along the cis‐trans axis of the organelle. How such compartmentalized localization of enzymes is achieved and how it contributes to glycosylation are not clear. Here, we show that the Golgi matrix protein GRASP55 directs the compartmentalized localization of key enzymes involved in glycosphingolipid (GSL) biosynthesis. GRASP55 binds to these enzymes and prevents their entry into COPI‐based retrograde transport vesicles, thus concentrating them in the trans‐Golgi. In genome‐edited cells lacking GRASP55, or in cells expressing mutant enzymes without GRASP55 binding sites, these enzymes relocate to the cis‐Golgi, which affects glycosphingolipid biosynthesis by changing flux across metabolic branch points. These findings reveal a mechanism by which a matrix protein regulates polarized localization of glycosylation enzymes in the Golgi and controls competition in glycan biosynthesis.
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Affiliation(s)
- Prathyush Pothukuchi
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Ilenia Agliarulo
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Marinella Pirozzi
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Riccardo Rizzo
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Domenico Russo
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Gabriele Turacchio
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Julian Nüchel
- Medical Faculty, Center for Biochemistry, University of Cologne, Cologne, Germany
| | - Jia-Shu Yang
- Division of Rheumatology, Inflammation and Immunity, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Charlotte Gehin
- École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Laura Capolupo
- École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | | | - Ansuman Biswas
- National Center of Biological Sciences, Bengaluru, India
| | - Giovanna Vanacore
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Nina Dathan
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Takahiro Nitta
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Petra Henklein
- Universitätsmedizin Berlin Institut für Biochemie Charité CrossOver Charitéplatz 1 / Sitz, Berlin, Germany
| | - Mukund Thattai
- National Center of Biological Sciences, Bengaluru, India
| | - Jin-Ichi Inokuchi
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Victor W Hsu
- Division of Rheumatology, Inflammation and Immunity, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Markus Plomann
- Medical Faculty, Center for Biochemistry, University of Cologne, Cologne, Germany
| | - Lina M Obeid
- Stony Brook University Medical Center, Stony Brook, NY, USA
| | - Yusuf A Hannun
- Stony Brook University Medical Center, Stony Brook, NY, USA
| | - Alberto Luini
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy
| | - Giovanni D'Angelo
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, Rome, Italy.,École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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9
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Lauri A, Fasano G, Venditti M, Dallapiccola B, Tartaglia M. In vivo Functional Genomics for Undiagnosed Patients: The Impact of Small GTPases Signaling Dysregulation at Pan-Embryo Developmental Scale. Front Cell Dev Biol 2021; 9:642235. [PMID: 34124035 PMCID: PMC8194860 DOI: 10.3389/fcell.2021.642235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/12/2021] [Indexed: 12/24/2022] Open
Abstract
While individually rare, disorders affecting development collectively represent a substantial clinical, psychological, and socioeconomic burden to patients, families, and society. Insights into the molecular mechanisms underlying these disorders are required to speed up diagnosis, improve counseling, and optimize management toward targeted therapies. Genome sequencing is now unveiling previously unexplored genetic variations in undiagnosed patients, which require functional validation and mechanistic understanding, particularly when dealing with novel nosologic entities. Functional perturbations of key regulators acting on signals' intersections of evolutionarily conserved pathways in these pathological conditions hinder the fine balance between various developmental inputs governing morphogenesis and homeostasis. However, the distinct mechanisms by which these hubs orchestrate pathways to ensure the developmental coordinates are poorly understood. Integrative functional genomics implementing quantitative in vivo models of embryogenesis with subcellular precision in whole organisms contribute to answering these questions. Here, we review the current knowledge on genes and mechanisms critically involved in developmental syndromes and pediatric cancers, revealed by genomic sequencing and in vivo models such as insects, worms and fish. We focus on the monomeric GTPases of the RAS superfamily and their influence on crucial developmental signals and processes. We next discuss the effectiveness of exponentially growing functional assays employing tractable models to identify regulatory crossroads. Unprecedented sophistications are now possible in zebrafish, i.e., genome editing with single-nucleotide precision, nanoimaging, highly resolved recording of multiple small molecules activity, and simultaneous monitoring of brain circuits and complex behavioral response. These assets permit accurate real-time reporting of dynamic small GTPases-controlled processes in entire organisms, owning the potential to tackle rare disease mechanisms.
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Affiliation(s)
- Antonella Lauri
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | | | | | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
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10
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Fisher S, Kuna D, Caspary T, Kahn RA, Sztul E. ARF family GTPases with links to cilia. Am J Physiol Cell Physiol 2020; 319:C404-C418. [PMID: 32520609 PMCID: PMC7500214 DOI: 10.1152/ajpcell.00188.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The ADP-ribosylation factor (ARF) superfamily of regulatory GTPases, including both the ARF and ARF-like (ARL) proteins, control a multitude of cellular functions, including aspects of vesicular traffic, lipid metabolism, mitochondrial architecture, the assembly and dynamics of the microtubule and actin cytoskeletons, and other pathways in cell biology. Considering their general utility, it is perhaps not surprising that increasingly ARF/ARLs have been found in connection to primary cilia. Here, we critically evaluate the current knowledge of the roles four ARF/ARLs (ARF4, ARL3, ARL6, ARL13B) play in cilia and highlight key missing information that would help move our understanding forward. Importantly, these GTPases are themselves regulated by guanine nucleotide exchange factors (GEFs) that activate them and by GTPase-activating proteins (GAPs) that act as both effectors and terminators of signaling. We believe that the identification of the GEFs and GAPs and better models of the actions of these GTPases and their regulators will provide a much deeper understanding and appreciation of the mechanisms that underly ciliary functions and the causes of a number of human ciliopathies.
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Affiliation(s)
- Skylar Fisher
- 1Department of Biochemistry, Emory University
School of Medicine, Atlanta,
Georgia
| | - Damian Kuna
- 2Department of Cell, Developmental and Integrative
Biology, University of Alabama at Birmingham,
Birmingham, Alabama
| | - Tamara Caspary
- 3Department of Human Genetics, Emory
University School of Medicine, Atlanta,
Georgia
| | - Richard A. Kahn
- 1Department of Biochemistry, Emory University
School of Medicine, Atlanta,
Georgia
| | - Elizabeth Sztul
- 2Department of Cell, Developmental and Integrative
Biology, University of Alabama at Birmingham,
Birmingham, Alabama
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11
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Turn RE, East MP, Prekeris R, Kahn RA. The ARF GAP ELMOD2 acts with different GTPases to regulate centrosomal microtubule nucleation and cytokinesis. Mol Biol Cell 2020; 31:2070-2091. [PMID: 32614697 PMCID: PMC7543072 DOI: 10.1091/mbc.e20-01-0012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
ELMOD2 is a ∼32 kDa protein first purified by its GTPase-activating protein (GAP) activity toward ARL2 and later shown to have uniquely broad specificity toward ARF family GTPases in in vitro assays. To begin the task of defining its functions in cells, we deleted ELMOD2 in immortalized mouse embryonic fibroblasts and discovered a number of cellular defects, which are reversed upon expression of ELMOD2-myc. We show that these defects, resulting from the loss of ELMOD2, are linked to two different pathways and two different GTPases: with ARL2 and TBCD to support microtubule nucleation from centrosomes and with ARF6 in cytokinesis. These data highlight key aspects of signaling by ARF family GAPs that contribute to previously underappreciated sources of complexity, including GAPs acting from multiple sites in cells, working with multiple GTPases, and contributing to the spatial and temporal control of regulatory GTPases by serving as both GAPs and effectors.
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Affiliation(s)
- Rachel E Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322.,Biochemistry, Cell & Developmental Biology Graduate Program, Laney Graduate School, Emory University, Atlanta, GA 30307
| | - Michael P East
- Department of Pharmacology, University of North Carolina Chapel Hill, Chapel Hill, NC 27599
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, University of Colorado, Aurora, CO 80045
| | - Richard A Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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12
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Makes caterpillars floppy-like effector-containing MARTX toxins require host ADP-ribosylation factor (ARF) proteins for systemic pathogenicity. Proc Natl Acad Sci U S A 2019; 116:18031-18040. [PMID: 31427506 PMCID: PMC6731672 DOI: 10.1073/pnas.1905095116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
MARTX toxins present across multiple bacterial genera are primary virulence factors that facilitate initial colonization, dissemination, and lethality in a wide range of hosts, including humans. Upon entry into host cells, the toxins undergo a processing event to release their disease-related modularly structured effector domains. However, the mechanisms underlying processing and activation of diverse effector domains within the toxins remain unclear. Here, we use biochemical and structural biological approaches, in combination with cellular microbiological experiments, to demonstrate how Makes caterpillars floppy-like effector (MCF) or its homolog-containing MARTX toxins process effector modules and fully activate effectors. MCF-containing toxins target ADP-ribosylation factor proteins ubiquitously expressed in cells to activate and disseminate effectors across subcellular compartments simultaneously, eventually leading to systemic pathogenicity. Upon invading target cells, multifunctional autoprocessing repeats-in-toxin (MARTX) toxins secreted by bacterial pathogens release their disease-related modularly structured effector domains. However, it is unclear how a diverse repertoire of effector domains within these toxins are processed and activated. Here, we report that Makes caterpillars floppy-like effector (MCF)-containing MARTX toxins require ubiquitous ADP-ribosylation factor (ARF) proteins for processing and activation of intermediate effector modules, which localize in different subcellular compartments following limited processing of holo effector modules by the internal cysteine protease. Effector domains structured tandemly with MCF in intermediate modules become disengaged and fully activated by MCF, which aggressively interacts with ARF proteins present at the same location as intermediate modules and is converted allosterically into a catalytically competent protease. MCF-mediated effector processing leads ultimately to severe virulence in mice via an MCF-mediated ARF switching mechanism across subcellular compartments. This work provides insight into how bacteria take advantage of host systems to induce systemic pathogenicity.
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13
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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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14
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Despres J, Ramdani Y, di Giovanni M, Bénard M, Zahid A, Montero-Hadjadje M, Yvergnaux F, Saguet T, Driouich A, Follet-Gueye ML. Replicative senescence of human dermal fibroblasts affects structural and functional aspects of the Golgi apparatus. Exp Dermatol 2019; 28:922-932. [DOI: 10.1111/exd.13886] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/14/2018] [Accepted: 01/02/2019] [Indexed: 01/02/2023]
Affiliation(s)
- Julie Despres
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale; Normandie Université; UNIROUEN, Fédération de recherche Normandie-Végétal - FED 4277, GDR CNRS 3711, COSM'ACTIFS; Mont-Saint-Aignan France
- Bioeurope; Groupe SOLABIA; Route d'OulinsAnet France
| | - Yasmina Ramdani
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale; Normandie Université; UNIROUEN, Fédération de recherche Normandie-Végétal - FED 4277, GDR CNRS 3711, COSM'ACTIFS; Mont-Saint-Aignan France
| | - Marine di Giovanni
- Cell Imaging Platform (PRIMACEN-IRIB); Normandie Université; UNIROUEN; Mont-Saint-Aignan France
| | - Magalie Bénard
- Cell Imaging Platform (PRIMACEN-IRIB); Normandie Université; UNIROUEN; Mont-Saint-Aignan France
| | - Abderrakib Zahid
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale; Normandie Université; UNIROUEN, Fédération de recherche Normandie-Végétal - FED 4277, GDR CNRS 3711, COSM'ACTIFS; Mont-Saint-Aignan France
| | - Maité Montero-Hadjadje
- Laboratoire de Différenciation et Communication Neuronale et Neuroendocrine; Institut de Recherche et d'Innovation Biomédicale de Normandie; Normandie Univ; UNIROUEN; INSERM U1239; Rouen France
| | | | | | - Azeddine Driouich
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale; Normandie Université; UNIROUEN, Fédération de recherche Normandie-Végétal - FED 4277, GDR CNRS 3711, COSM'ACTIFS; Mont-Saint-Aignan France
- Cell Imaging Platform (PRIMACEN-IRIB); Normandie Université; UNIROUEN; Mont-Saint-Aignan France
| | - Marie-Laure Follet-Gueye
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale; Normandie Université; UNIROUEN, Fédération de recherche Normandie-Végétal - FED 4277, GDR CNRS 3711, COSM'ACTIFS; Mont-Saint-Aignan France
- Cell Imaging Platform (PRIMACEN-IRIB); Normandie Université; UNIROUEN; Mont-Saint-Aignan France
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15
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Hong X, Jeyifous O, Ronilo M, Marshall J, Green WN, Standley S. A novel function for the ER retention signals in the C-terminus of kainate receptor subunit, GluK5. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:459-473. [PMID: 30339823 DOI: 10.1016/j.bbamcr.2018.10.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 11/30/2022]
Abstract
Classically, endoplasmic reticulum (ER) retention signals in secreted integral membrane proteins impose the requirement to assemble with other cognate subunits to form functional assemblies before they can exit the ER. We report that GluK5 has two ER retention signals in its cytoplasmic C-terminus: an arginine-based signal and a di-leucine motif previously thought to be an endocytic motif. GluK5 assembles with GluK2, but surprisingly GluK2 association does little to block the ER retention signals. We find instead that the ER retention signals are blocked by two proteins involved in intracellular trafficking, SAP97 and CASK. We show that SAP97, in the presence of CASK and the receptor complex, assumes an extended conformation. In the extended conformation, SAP97 makes its SH3 and GuK domains available to bind and sterically mask the ER retention signals in the GluK5 C-terminus. SAP97 and CASK are also necessary for sorting receptor cargoes into the local dendritic secretory pathway in neurons. We show that the ER retention signals of GluK5 play a vital role in sorting the receptor complex in the local dendritic secretory pathway in neurons. These data suggest a new role for ER retention signals in trafficking integral membrane proteins in neurons. SIGNIFICANCE: We present evidence that the ER retention signals in the kainate receptors containing GluK5 impose a requirement for sorting into local dendritic secretory pathways in neurons, as opposed to traversing the somatic Golgi apparatus. There are two ER retention signals in the C-terminus of GluK5. We show that both are blocked by physical association with SAP97 and CASK. The SH3 and GuK domains of SAP97, in the presence of CASK, bind directly to each ER retention signal and form a complex. These results support an entirely new function for ER retention signals in the C-termini of neuronal receptors, such as NMDA and kainate receptors, and define a mechanism for selective entry of receptors into local secretory pathways.
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Affiliation(s)
- Xiaoqi Hong
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91711, United States of America
| | - Okunola Jeyifous
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, United States of America
| | - Mason Ronilo
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91711, United States of America
| | - John Marshall
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912, United States of America
| | - William N Green
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, United States of America
| | - Steve Standley
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91711, United States of America.
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16
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Luchsinger C, Aguilar M, Burgos PV, Ehrenfeld P, Mardones GA. Functional disruption of the Golgi apparatus protein ARF1 sensitizes MDA-MB-231 breast cancer cells to the antitumor drugs Actinomycin D and Vinblastine through ERK and AKT signaling. PLoS One 2018; 13:e0195401. [PMID: 29614107 PMCID: PMC5882166 DOI: 10.1371/journal.pone.0195401] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 03/21/2018] [Indexed: 12/26/2022] Open
Abstract
Increasing evidence indicates that the Golgi apparatus plays active roles in cancer, but a comprehensive understanding of its functions in the oncogenic transformation has not yet emerged. At the same time, the Golgi is becoming well recognized as a hub that integrates its functions of protein and lipid biosynthesis to signal transduction for cell proliferation and migration in cancer cells. Nevertheless, the active function of the Golgi apparatus in cancer cells has not been fully evaluated as a target for combined treatment. Here, we analyzed the effect of perturbing the Golgi apparatus on the sensitivity of the MDA-MB-231 breast cancer cell line to the drugs Actinomycin D and Vinblastine. We disrupted the function of ARF1, a protein necessary for the homeostasis of the Golgi apparatus. We found that the expression of the ARF1-Q71L mutant increased the sensitivity of MDA-MB-231 cells to both Actinomycin D and Vinblastine, resulting in decreased cell proliferation and cell migration, as well as in increased apoptosis. Likewise, the combined treatment of cells with Actinomycin D or Vinblastine and Brefeldin A or Golgicide A, two disrupting agents of the ARF1 function, resulted in similar effects on cell proliferation, cell migration and apoptosis. Interestingly, each combined treatment had distinct effects on ERK1/2 and AKT signaling, as indicated by the decreased levels of either phospho-ERK1/2 or phospho-AKT. Our results suggest that disruption of Golgi function could be used as a strategy for the sensitization of cancer cells to chemotherapy.
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Affiliation(s)
- Charlotte Luchsinger
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
- Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Marcelo Aguilar
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
- Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Patricia V. Burgos
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
- Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
- Center for Cell Biology and Biomedicine (CEBICEM), School of Medicine and Science, Universidad San Sebastián, Santiago, Chile
- Center for Aging and Regeneration (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pamela Ehrenfeld
- Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
- Department of Anatomy, Histology and Pathology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Gonzalo A. Mardones
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
- Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
- Center for Cell Biology and Biomedicine (CEBICEM), School of Medicine and Science, Universidad San Sebastián, Santiago, Chile
- * E-mail:
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17
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Gilbert CE, Sztul E, Machamer CE. Commonly used trafficking blocks disrupt ARF1 activation and the localization and function of specific Golgi proteins. Mol Biol Cell 2018; 29:937-947. [PMID: 29467256 PMCID: PMC5896932 DOI: 10.1091/mbc.e17-11-0622] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cold temperature blocks used to synchronize protein trafficking inhibit GBF1 function, leading to a decrease in ARF1-GTP levels and mislocalization of the ARF1 effector golgin-160. Several other, but not all, Golgi proteins including ARL1 also mislocalize. ARF1 activity and golgin-160 localization require more than 30 min to recover from these blocks. ADP-ribosylation factor (ARF) proteins are key regulators of the secretory pathway. ARF1, through interacting with its effectors, regulates protein trafficking by facilitating numerous events at the Golgi. One unique ARF1 effector is golgin-160, which promotes the trafficking of only a specific subset of cargo proteins through the Golgi. While studying this role of golgin-160, we discovered that commonly used cold temperature blocks utilized to synchronize cargo trafficking (20 and 16°C) caused golgin-160 dispersal from Golgi membranes. Here, we show that the loss of golgin-160 localization correlates with a decrease in the levels of activated ARF1, and that golgin-160 dispersal can be prevented by expression of a GTP-locked ARF1 mutant. Overexpression of the ARF1 activator Golgi brefeldin A–resistant guanine nucleotide exchange factor 1 (GBF1) did not prevent golgin-160 dispersal, suggesting that GBF1 may be nonfunctional at lower temperatures. We further discovered that several other Golgi resident proteins had altered localization at lower temperatures, including proteins recruited by ARF-like GTPase 1 (ARL1), a small GTPase that also became dispersed in the cold. Although cold temperature blocks are useful for synchronizing cargo trafficking through the Golgi, our data indicate that caution must be taken when interpreting results from these assays.
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Affiliation(s)
- Catherine E Gilbert
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35924
| | - Carolyn E Machamer
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
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18
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Ivanova AA, Caspary T, Seyfried NT, Duong DM, West AB, Liu Z, Kahn RA. Biochemical characterization of purified mammalian ARL13B protein indicates that it is an atypical GTPase and ARL3 guanine nucleotide exchange factor (GEF). J Biol Chem 2017; 292:11091-11108. [PMID: 28487361 PMCID: PMC5491791 DOI: 10.1074/jbc.m117.784025] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 05/02/2017] [Indexed: 12/11/2022] Open
Abstract
Primary cilia play central roles in signaling during metazoan development. Several key regulators of ciliogenesis and ciliary signaling are mutated in humans, resulting in a number of ciliopathies, including Joubert syndrome (JS). ARL13B is a ciliary GTPase with at least three missense mutations identified in JS patients. ARL13B is a member of the ADP ribosylation factor family of regulatory GTPases, but is atypical in having a non-homologous, C-terminal domain of ∼20 kDa and at least one key residue difference in the consensus GTP-binding motifs. For these reasons, and to establish a solid biochemical basis on which to begin to model its actions in cells and animals, we developed preparations of purified, recombinant, murine Arl13b protein. We report results from assays for solution-based nucleotide binding, intrinsic and GTPase-activating protein-stimulated GTPase, and ARL3 guanine nucleotide exchange factor activities. Biochemical analyses of three human missense mutations found in JS and of two consensus GTPase motifs reinforce the atypical properties of this regulatory GTPase. We also discovered that murine Arl13b is a substrate for casein kinase 2, a contaminant in our preparation from human embryonic kidney cells. This activity, and the ability of casein kinase 2 to use GTP as a phosphate donor, may be a source of differences between our data and previously published results. These results provide a solid framework for further research into ARL13B on which to develop models for the actions of this clinically important cell regulator.
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Affiliation(s)
| | - Tamara Caspary
- Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322 and
| | | | | | - Andrew B West
- the Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Zhiyong Liu
- the Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, Birmingham, Alabama 35294
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19
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Newman LE, Schiavon CR, Turn RE, Kahn RA. The ARL2 GTPase regulates mitochondrial fusion from the intermembrane space. CELLULAR LOGISTICS 2017; 7:e1340104. [PMID: 28944094 PMCID: PMC5602422 DOI: 10.1080/21592799.2017.1340104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/05/2017] [Indexed: 01/11/2023]
Abstract
Mitochondria are essential, dynamic organelles that regularly undergo both fusion and fission in response to cellular conditions, though mechanisms of the regulation of their dynamics are incompletely understood. We provide evidence that increased activity of the small GTPase ARL2 is strongly correlated with an increase in fusion, while loss of ARL2 activity results in a decreased rate of mitochondrial fusion. Strikingly, expression of activated ARL2 can partially restore the loss of fusion resulting from deletion of either mitofusin 1 (MFN1) or mitofusin 2 (MFN2), but not deletion of both. We only observe the full effects of ARL2 on mitochondrial fusion when it is present in the intermembrane space (IMS), as constructs driven to the matrix or prevented from entering mitochondria are essentially inactive in promoting fusion. Thus, ARL2 is the first regulatory (small) GTPase shown to act inside mitochondria or in the fusion pathway. Finally, using high-resolution, structured illumination microscopy (SIM), we find that ARL2 and mitofusin immunoreactivities present as punctate staining along mitochondria that share a spatial convergence in fluorescence signals. Thus, we propose that ARL2 plays a regulatory role in mitochondrial fusion, acting from the IMS and requiring at least one of the mitofusins in their canonical role in fusion of the outer membranes.
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Affiliation(s)
- Laura E. Newman
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Cara R. Schiavon
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Rachel E. Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
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20
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Wang C, Timmons CL, Shao Q, Kinlock BL, Turner TM, Iwamoto A, Zhang H, Liu H, Liu B. GB virus type C E2 protein inhibits human immunodeficiency virus type 1 Gag assembly by downregulating human ADP-ribosylation factor 1. Oncotarget 2016; 6:43293-309. [PMID: 26675377 PMCID: PMC4791233 DOI: 10.18632/oncotarget.6537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 11/21/2015] [Indexed: 12/28/2022] Open
Abstract
GB virus type C (GBV-C) glycoprotein E2 protein disrupts HIV-1 assembly and release by inhibiting Gag plasma membrane targeting, however the mechanism by which the GBV-C E2 inhibits Gag trafficking remains unclear. In the present study, we identified ADP-ribosylation factor 1 (ARF1) contributed to the inhibitory effect of GBV-C E2 on HIV-1 Gag membrane targeting. Expression of GBV-C E2 decreased ARF1 expression in a proteasomal degradation-dependent manner. The restoration of ARF1 expression rescued the HIV-1 Gag processing and membrane targeting defect imposed by GBV-C E2. In addition, GBV-C E2 expression also altered Golgi morphology and suppressed protein traffic through the secretory pathway, which are all consistent with a phenotype of disrupting the function of ARF1 protein. Thus, our results indicate that GBV-C E2 inhibits HIV-1 assembly and release by decreasing ARF1, and may provide insights regarding GBV-C E2's potential for a new therapeutic approach for treating HIV-1.
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Affiliation(s)
- Chenliang Wang
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, USA.,Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Department of Clinical Laboratory, Guangdong Institute of Gastroenterology and The Sixth Affiliated Hospital, Institute of Human Virology and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Christine L Timmons
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, USA
| | - Qiujia Shao
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, USA
| | - Ballington L Kinlock
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, USA
| | - Tiffany M Turner
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, USA
| | - Aikichi Iwamoto
- Division of Infectious Diseases, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Hui Zhang
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Department of Clinical Laboratory, Guangdong Institute of Gastroenterology and The Sixth Affiliated Hospital, Institute of Human Virology and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Huanliang Liu
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Department of Clinical Laboratory, Guangdong Institute of Gastroenterology and The Sixth Affiliated Hospital, Institute of Human Virology and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Bindong Liu
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, USA
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21
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Mariani LE, Bijlsma MF, Ivanova AA, Suciu SK, Kahn RA, Caspary T. Arl13b regulates Shh signaling from both inside and outside the cilium. Mol Biol Cell 2016; 27:mbc.E16-03-0189. [PMID: 27682584 PMCID: PMC5170560 DOI: 10.1091/mbc.e16-03-0189] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 08/16/2016] [Accepted: 09/20/2016] [Indexed: 12/21/2022] Open
Abstract
The regulatory GTPase Arl13b localizes to primary cilia, where it regulates Sonic hedgehog (Shh) signaling. Missense mutations in ARL13B can cause the ciliopathy Joubert syndrome, while the mouse null allele is embryonic lethal. We used mouse embryonic fibroblasts as a system to determine the effects of Arl13b mutations on Shh signaling. We tested a total of seven different mutants, three JS-causing variants, two point mutants predicted to alter guanine nucleotide handling, one that disrupts cilia localization, and one that prevents palmitoylation and thus membrane binding, in assays of transcriptional and non-transcriptional Shh signaling. We found that mutations disrupting Arl13b's palmitoylation site, cilia localization signal, or GTPase handling altered the Shh response in distinct assays of transcriptional or non-transcriptional signaling. In contrast, JS-causing mutations in Arl13b did not affect Shh signaling in these same assays, suggesting these mutations result in more subtle defects, likely affecting only a subset of signaling outputs. Finally, we show that restricting Arl13b from cilia interferes with its ability to regulate Shh-stimulated chemotaxis, despite previous evidence that cilia themselves are not required for this non-transcriptional Shh response. This points to a more complex relationship between the ciliary and non-ciliary roles of this regulatory GTPase than previously envisioned.
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Affiliation(s)
- Laura E Mariani
- *Department of Human Genetics, Emory University, Atlanta, GA, USA Neuroscience Graduate Program, Emory University, Atlanta, GA, USA
| | - Maarten F Bijlsma
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Academic Medical Center and Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Anna A Ivanova
- Department of Biochemistry, Emory University, Atlanta, GA, USA
| | - Sarah K Suciu
- *Department of Human Genetics, Emory University, Atlanta, GA, USA Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA, USA
| | - Richard A Kahn
- Department of Biochemistry, Emory University, Atlanta, GA, USA
| | - Tamara Caspary
- *Department of Human Genetics, Emory University, Atlanta, GA, USA
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22
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Naramoto S, Dainobu T, Tokunaga H, Kyozuka J, Fukuda H. Cellular and developmental function of ACAP type ARF-GAP proteins are diverged in plant cells. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2016; 33:309-314. [PMID: 31274992 PMCID: PMC6565945 DOI: 10.5511/plantbiotechnology.16.0309a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 03/09/2016] [Indexed: 05/29/2023]
Abstract
Vesicle transport is crucial for various cellular functions and development of multicellular organisms. ARF-GAP is one of the key regulators of vesicle transport and is diverse family of proteins. Arabidopsis has 15 ARF-GAP proteins and four members are classified as ACAP type ARF-GAP proteins. Our previous study identified that VASCULAR NETWORK DEFECTIVE3 (VAN3), an ACAP ARF-GAP, played crucial roles in leaf vascular formation. However, it remains question how other members of plant ACAP ARF-GAPs function in cellular and developmental processes. To characterize these, we analyzed spatial expression pattern and subcellular localization of VAN3 and three other ACAPs, so called VAN3-like proteins (VALs). Expression pattern analysis revealed that they were expressed in distinctive developmental processes. Subcellular localization analysis in protoplast cells indicated that in contrast to VAN3, which localizes on trans-Golgi networks/early endosomes (TGNs/EEs), VAL1 and VAL2 were localized on ARA6-labelled endosomes, and VAL3 resided mainly in the cytoplasm. These results indicated that VAN3 and VALs are differently expressed in a tissue level and function in different intracellular compartments, in spite of their significant sequence similarities. These findings suggested functional divergence among plant ACAPs. Cellular localizations of all members of animal ACAP proteins are identical. Therefore our findings also suggested that plant evolved ACAP proteins in plant specific manner.
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Affiliation(s)
- Satoshi Naramoto
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Tomoko Dainobu
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Hiroki Tokunaga
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Junko Kyozuka
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Hiroo Fukuda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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23
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Abstract
Mutant genes that underlie Mendelian forms of amyotrophic lateral sclerosis (ALS) and biochemical investigations of genetic disease models point to potential driver pathophysiological events involving endoplasmic reticulum (ER) stress and autophagy. Several steps in these cell biological processes are known to be controlled physiologically by small ADP-ribosylation factor (ARF) signaling. Here, we investigated the role of ARF guanine nucleotide exchange factors (GEFs), cytohesins, in models of ALS. Genetic or pharmacological inhibition of cytohesins protects motor neurons in vitro from proteotoxic insults and rescues locomotor defects in a Caenorhabditis elegans model of disease. Cytohesins form a complex with mutant superoxide dismutase 1 (SOD1), a known cause of familial ALS, but this is not associated with a change in GEF activity or ARF activation. ER stress evoked by mutant SOD1 expression is alleviated by antagonism of cytohesin activity. In the setting of mutant SOD1 toxicity, inhibition of cytohesin activity enhances autophagic flux and reduces the burden of misfolded SOD1. These observations suggest that targeting cytohesins may have potential benefits for the treatment of ALS.
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24
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Newman LE, Zhou CJ, Mudigonda S, Mattheyses AL, Paradies E, Marobbio CMT, Kahn RA. The ARL2 GTPase is required for mitochondrial morphology, motility, and maintenance of ATP levels. PLoS One 2014; 9:e99270. [PMID: 24911211 PMCID: PMC4050054 DOI: 10.1371/journal.pone.0099270] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/13/2014] [Indexed: 02/06/2023] Open
Abstract
ARF-like 2 (ARL2) is a member of the ARF family and RAS superfamily of regulatory GTPases, predicted to be present in the last eukaryotic common ancestor, and essential in a number of model genetic systems. Though best studied as a regulator of tubulin folding, we previously demonstrated that ARL2 partially localizes to mitochondria. Here, we show that ARL2 is essential to a number of mitochondrial functions, including mitochondrial morphology, motility, and maintenance of ATP levels. We compare phenotypes resulting from ARL2 depletion and expression of dominant negative mutants and use these to demonstrate that the mitochondrial roles of ARL2 are distinct from its roles in tubulin folding. Testing of current models for ARL2 actions at mitochondria failed to support them. Rather, we found that knockdown of the ARL2 GTPase activating protein (GAP) ELMOD2 phenocopies two of three phenotypes of ARL2 siRNA, making it a likely effector for these actions. These results add new layers of complexity to ARL2 signaling, highlighting the need to deconvolve these different cell functions. We hypothesize that ARL2 plays essential roles inside mitochondria along with other cellular functions, at least in part to provide coupling of regulation between these essential cell processes.
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Affiliation(s)
- Laura E. Newman
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Cheng-jing Zhou
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Samatha Mudigonda
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Alexa L. Mattheyses
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Eleonora Paradies
- Consiglio Nazionale delle Ricerche Institute of Biomembranes and Bioenergetics, Bari, Italy
| | | | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, United States of America
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25
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Valenzuela JI, Jaureguiberry-Bravo M, Salas DA, Ramírez OA, Cornejo VH, Lu HE, Blanpied TA, Couve A. Transport along the dendritic endoplasmic reticulum mediates the trafficking of GABAB receptors. J Cell Sci 2014; 127:3382-95. [PMID: 24895402 DOI: 10.1242/jcs.151092] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In neurons, secretory organelles within the cell body are complemented by the dendritic endoplasmic reticulum (ER) and Golgi outposts (GOPs), whose role in neurotransmitter receptor trafficking is poorly understood. γ-aminobutyric acid (GABA) type B metabotropic receptors (GABABRs) regulate the efficacy of synaptic transmission throughout the brain. Their plasma membrane availability is controlled by mechanisms involving an ER retention motif and assembly-dependent ER export. Thus, they constitute an ideal molecular model to study ER trafficking, but the extent to which the dendritic ER participates in GABABR biosynthesis has not been thoroughly explored. Here, we show that GABAB1 localizes preferentially to the ER in dendrites and moves long distances within this compartment. Not only diffusion but also microtubule and dynein-dependent mechanisms control dendritic ER transport. GABABRs insert throughout the somatodendritic plasma membrane but dendritic post-ER carriers containing GABABRs do not fuse selectively with GOPs. This study furthers our understanding of the spatial selectivity of neurotransmitter receptors for dendritic organelles.
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Affiliation(s)
- José I Valenzuela
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Matías Jaureguiberry-Bravo
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Daniela A Salas
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Omar A Ramírez
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Program of Anatomy and Development, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Víctor H Cornejo
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Hsiangmin E Lu
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Andrés Couve
- Program of Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile Biomedical Neuroscience Institute, BNI, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
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26
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van den Bosch MTJ, Poole AW, Hers I. Cytohesin-2 phosphorylation by protein kinase C relieves the constitutive suppression of platelet dense granule secretion by ADP-ribosylation factor 6. J Thromb Haemost 2014; 12:726-35. [PMID: 24581425 PMCID: PMC4238808 DOI: 10.1111/jth.12542] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/19/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Protein kinase C (PKC) is a major regulator of platelet function and secretion. The underlying molecular pathway from PKC to secretion, however, is poorly understood. By a proteomics screen we identified the guanine nucleotide exchange factor cytohesin-2 as a candidate PKC substrate. OBJECTIVES We aimed to validate cytohesin-2 as a PKC substrate in platelets and to determine its role in granule secretion and other platelet responses. METHODS AND RESULTS Immunoprecipitation was performed with a phosphoserine PKC substrate antibody followed by mass spectrometry, leading to the identification of cytohesin-2. By western blotting we showed that different agonists induced cytohesin-2 phosphorylation by PKC. Protein function was investigated using a pharmacological approach. The cytohesin inhibitor SecinH3 significantly enhanced platelet dense granule secretion and aggregation, as measured by lumi-aggregometry. Flow cytometry data indicate that α-granule release and integrin αII b β3 activation were not affected by cytohesin-2 inhibition. Lysosome secretion was assessed by a colorimetric assay and was also unchanged. As shown by western blotting, ARF6 interacted with cytohesin-2 and was present in an active GTP-bound form under basal conditions. Upon platelet stimulation, this interaction was largely lost and ARF6 activation decreased, both of which could be rescued by PKC inhibition. CONCLUSIONS Cytohesin-2 constitutively suppresses platelet dense granule secretion and aggregation by keeping ARF6 in a GTP-bound state. PKC-mediated phosphorylation of cytohesin-2 relieves this inhibitory effect, thereby promoting platelet secretion and aggregation.
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27
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Dong Z, Zuber C, Pierce M, Stanley P, Roth J. Reduction in Golgi apparatus dimension in the absence of a residential protein, N-acetylglucosaminyltransferase V. Histochem Cell Biol 2014; 141:153-64. [PMID: 24078077 PMCID: PMC4085668 DOI: 10.1007/s00418-013-1146-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2013] [Indexed: 11/28/2022]
Abstract
Various proteins are involved in the generation and maintenance of the membrane complex known as the Golgi apparatus. We have used mutant Chinese hamster ovary (CHO) cell lines Lec4 and Lec4A lacking N-acetylglucosaminyltransferase V (GlcNAcT-V, MGAT5) activity and protein in the Golgi apparatus to study the effects of the absence of a single glycosyltransferase on the Golgi apparatus dimension. Quantification of immunofluorescence in serial confocal sections for Golgi α-mannosidase II and electron microscopic morphometry revealed a reduction in Golgi volume density up to 49 % in CHO Lec4 and CHO Lec4A cells compared to parental CHO cells. This reduction in Golgi volume density could be reversed by stable transfection of Lec4 cells with a cDNA encoding Mgat5. Inhibition of the synthesis of β1,6-branched N-glycans by swainsonine had no effect on Golgi volume density. In addition, no effect on Golgi volume density was observed in CHO Lec1 cells that contain enzymatically active GlcNAcT-V, but cannot synthesize β1,6-branched glycans due to an inactive GlcNAcT-I in their Golgi apparatus. These results indicate that it may be the absence of the GlcNAcT-V protein that is the determining factor in reducing Golgi volume density. No dimensional differences existed in cross-sectioned cisternal stacks between Lec4 and control CHO cells, but significantly reduced Golgi stack hits were observed in cross-sectioned Lec4 cells. Therefore, the Golgi apparatus dimensional change in Lec4 and Lec4A cells may be due to a compaction of the organelle.
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Affiliation(s)
- Zhizhong Dong
- Division of Cell and Molecular Pathology, Department of Pathology, University of Zürich, 8091 Zürich, Switzerland
| | - Christian Zuber
- Division of Cell and Molecular Pathology, Department of Pathology, University of Zürich, 8091 Zürich, Switzerland
| | - Michael Pierce
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Pamela Stanley
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Jürgen Roth
- Division of Cell and Molecular Pathology, Department of Pathology, University of Zürich, 8091 Zürich, Switzerland
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28
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Abstract
As an obligate pathogen, influenza virus requires host cell factors and compartments to mediate productive infection and to produce infectious progeny virus. Recently, several small interfering RNA (siRNA) knockdown screens revealed influenza virus host dependency proteins, all of which identified at least two subunits of the coat protein I (COPI) complex. COPI proteins oligomerize to form coated vesicles that transport contents between the Golgi apparatus and the endoplasmic reticulum, and they have also been reported to mediate endosomal trafficking. However, it remains unclear which steps in the influenza virus infection cycle rely on the COPI complex. Upon systematic dissection of the influenza virus infection cycle, from entry to progeny virion production, we found that prolonged exposure to COPI complex disruption through siRNA depletion resulted in significant defects in virus internalization and trafficking to late endosomes. Acute inhibition of COPI complex recruitment to the Golgi apparatus with pharmacological compounds failed to recapitulate the same entry defects as observed with the COPI-depleted cells but did result in specific decreases in viral membrane protein expression and assembly, leading to defects in progeny virion production. Taken together, our findings suggest that COPI complexes likely function indirectly in influenza virus entry but play direct roles in viral membrane protein expression and assembly.
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29
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Sheen VL. Periventricular Heterotopia: Shuttling of Proteins through Vesicles and Actin in Cortical Development and Disease. SCIENTIFICA 2012; 2012:480129. [PMID: 24278701 PMCID: PMC3820590 DOI: 10.6064/2012/480129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 10/14/2012] [Indexed: 06/02/2023]
Abstract
During cortical development, proliferating neural progenitors exhibit polarized apical and basolateral membranes that are maintained by tightly controlled and membrane-specific vesicular trafficking pathways. Disruption of polarity through impaired delivery of proteins can alter cell fate decisions and consequent expansion of the progenitor pool, as well as impact the integrity of the neuroependymal lining. Loss of neuroependymal integrity disrupts radial glial scaffolding and alters initial neuronal migration from the ventricular zone. Vesicle trafficking is also required for maintenance of lipid and protein cycling within the leading and trailing edge of migratory neurons, as well as dendrites and synapses of mature neurons. Defects in this transport machinery disrupt neuronal identity, migration, and connectivity and give rise to a malformation of cortical development termed as periventricular heterotopia (PH). PH is characterized by a reduction in brain size, ectopic clusters of neurons localized along the lateral ventricle, and epilepsy and dyslexia. These anatomical anomalies correlate with developmental impairments in neural progenitor proliferation and specification, migration from loss of neuroependymal integrity and neuronal motility, and aberrant neuronal process extension. Genes causal for PH regulate vesicle-mediated endocytosis along an actin cytoskeletal network. This paper explores the role of these dynamic processes in cortical development and disease.
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Affiliation(s)
- Volney L. Sheen
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
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30
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Valdés V, Valenzuela JI, Salas DA, Jaureguiberry-Bravo M, Otero C, Thiede C, Schmidt CF, Couve A. Endoplasmic reticulum sorting and kinesin-1 command the targeting of axonal GABAB receptors. PLoS One 2012; 7:e44168. [PMID: 22952914 PMCID: PMC3428321 DOI: 10.1371/journal.pone.0044168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 07/30/2012] [Indexed: 12/17/2022] Open
Abstract
In neuronal cells the intracellular trafficking machinery controls the availability of neurotransmitter receptors at the plasma membrane, which is a critical determinant of synaptic strength. Metabotropic γ amino-butyric acid (GABA) type B receptors (GABABRs) are neurotransmitter receptors that modulate synaptic transmission by mediating the slow and prolonged responses to GABA. GABABRs are obligatory heteromers constituted by two subunits, GABABR1 and GABABR2. GABABR1a and GABABR1b are the most abundant subunit variants. GABABR1b is located in the somatodendritic domain whereas GABABR1a is additionally targeted to the axon. Sushi domains located at the N-terminus of GABABR1a constitute the only difference between both variants and are necessary and sufficient for axonal targeting. The precise targeting machinery and the organelles involved in sorting and transport have not been described. Here we demonstrate that GABABRs require the Golgi apparatus for plasma membrane delivery but that axonal sorting and targeting of GABABR1a operate in a pre-Golgi compartment. In the axon GABABR1a subunits are enriched in the endoplasmic reticulum (ER), and their dynamic behavior and colocalization with other secretory organelles like the ER-to-Golgi intermediate compartment (ERGIC) suggest that they employ a local secretory route. The transport of axonal GABABR1a is microtubule-dependent and kinesin-1, a molecular motor of the kinesin family, determines axonal localization. Considering that progression of GABABRs through the secretory pathway is regulated by an ER retention motif our data contribute to understand the role of the axonal ER in non-canonical sorting and targeting of neurotransmitter receptors.
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Affiliation(s)
- Viviana Valdés
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - José Ignacio Valenzuela
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Daniela A. Salas
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Matías Jaureguiberry-Bravo
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- School of Biochemistry, Faculty of Biological Science, Universidad Andrés Bello, Santiago, Chile
| | - Carolina Otero
- Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Christina Thiede
- Georg-August-Universität, Fakultät für Physik, Drittes Physikalisches Institut-Biophysik, Göttingen, Germany
| | - Christoph F. Schmidt
- Georg-August-Universität, Fakultät für Physik, Drittes Physikalisches Institut-Biophysik, Göttingen, Germany
| | - Andrés Couve
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago, Chile
- * E-mail:
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STAGSTED JAN. Journey beyond immunology. Regulation of receptor internalization by major histocompatibility complex class I (MHC-I) and effect of peptides derived from MHC-I. APMIS 2011. [DOI: 10.1111/j.1600-0463.1998.tb05657.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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ADP ribosylation factor 1 activity is required to recruit AP-1 to the major histocompatibility complex class I (MHC-I) cytoplasmic tail and disrupt MHC-I trafficking in HIV-1-infected primary T cells. J Virol 2011; 85:12216-26. [PMID: 21917951 DOI: 10.1128/jvi.00056-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-1-infected cells are partially resistant to anti-HIV cytotoxic T lymphocytes (CTLs) due to the effects of the HIV Nef protein on antigen presentation by major histocompatibility complex class I (MHC-I), and evidence has been accumulating that this function of Nef is important in vivo. HIV Nef disrupts the normal expression of MHC-I by stabilizing a protein-protein interaction between the clathrin adaptor protein AP-1 and the MHC-I cytoplasmic tail. There is also evidence that Nef activates a phosphatidylinositol 3 kinase (PI3K)-dependent GTPase, ADP ribosylation factor 6 (ARF-6), to stimulate MHC-I internalization. However, the relative importance of these two pathways is unclear. Here we report that a GTPase required for AP-1 activity (ARF-1) was needed for Nef to disrupt MHC-I surface levels, whereas no significant requirement for ARF-6 was observed in Nef-expressing T cell lines and in HIV-infected primary T cells. An ARF-1 inhibitor blocked the ability of Nef to recruit AP-1 to the MHC-I cytoplasmic tail, and a dominant active ARF-1 mutant stabilized the Nef-MHC-I-AP-1 complex. These data support a model in which Nef and ARF-1 stabilize an interaction between MHC-I and AP-1 to disrupt the presentation of HIV-1 epitopes to CTLs.
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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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Carvou N, Holic R, Li M, Futter C, Skippen A, Cockcroft S. Phosphatidylinositol- and phosphatidylcholine-transfer activity of PITPbeta is essential for COPI-mediated retrograde transport from the Golgi to the endoplasmic reticulum. J Cell Sci 2010; 123:1262-73. [PMID: 20332109 DOI: 10.1242/jcs.061986] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vesicles formed by the COPI complex function in retrograde transport from the Golgi to the endoplasmic reticulum (ER). Phosphatidylinositol transfer protein beta (PITPbeta), an essential protein that possesses phosphatidylinositol (PtdIns) and phosphatidylcholine (PtdCho) lipid transfer activity is known to localise to the Golgi and ER but its role in these membrane systems is not clear. To examine the function of PITPbeta at the Golgi-ER interface, RNA interference (RNAi) was used to knockdown PITPbeta protein expression in HeLa cells. Depletion of PITPbeta leads to a decrease in PtdIns(4)P levels, compaction of the Golgi complex and protection from brefeldin-A-mediated dispersal to the ER. Using specific transport assays, we show that anterograde traffic is unaffected but that KDEL-receptor-dependent retrograde traffic is inhibited. This phenotype can be rescued by expression of wild-type PITPbeta but not by mutants defective in docking, PtdIns transfer and PtdCho transfer. These data demonstrate that the PtdIns and PtdCho exchange activity of PITPbeta is essential for COPI-mediated retrograde transport from the Golgi to the ER.
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Affiliation(s)
- Nicolas Carvou
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower St, London WC1E 6BT, UK
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Integrity of the early secretory pathway promotes, but is not required for, severe acute respiratory syndrome coronavirus RNA synthesis and virus-induced remodeling of endoplasmic reticulum membranes. J Virol 2009; 84:833-46. [PMID: 19889777 DOI: 10.1128/jvi.01826-09] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
To accommodate its RNA synthesis in the infected cell, severe acute respiratory syndrome coronavirus (SARS-CoV) induces a cytoplasmic reticulovesicular network (RVN) that is derived from endoplasmic reticulum (ER) membranes. We set out to investigate how the early secretory pathway interacts with the RVN and the viral replication/transcription complex (RTC) that is anchored to it. When the secretory pathway was disrupted by brefeldin A (BFA) treatment at the start of infection, RVN formation and viral RTC activity were not blocked and continued up to 11 h postinfection, although RNA synthesis was reduced by ca. 80%. In vitro RTC assays, using membrane fractions from infected cells, demonstrated that BFA does not directly interfere with the activity of the viral RNA-synthesizing enzymes. Confocal microscopy studies showed that early secretory pathway components are not associated with SARS-CoV-induced replication sites, although our studies revealed that infection induces a remarkable redistribution of the translocon subunit Sec61alpha. Ultrastructural studies, including electron tomography, revealed that the formation of the RVN and all its previously documented features can occur in the presence of BFA, despite differences in the volume and morphology of the network. We therefore conclude that early secretory pathway proteins do not play a direct role in RVN morphogenesis or the functionality of the SARS-CoV RTC. The BFA-induced disruption of ER integrity and functionality probably affects the overall quality of the membrane scaffold that is needed to support the viral RTC and/or the availability of specific host factors, which in turn compromises viral RNA synthesis.
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del Castillo FJ, Cohen-Salmon M, Charollais A, Caille D, Lampe PD, Chavrier P, Meda P, Petit C. Consortin, a trans-Golgi network cargo receptor for the plasma membrane targeting and recycling of connexins. Hum Mol Genet 2009; 19:262-75. [PMID: 19864490 DOI: 10.1093/hmg/ddp490] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Targeting of numerous transmembrane proteins to the cell surface is thought to depend on their recognition by cargo receptors that interact with the adaptor machinery for anterograde traffic at the distal end of the Golgi complex. We report here on consortin, a novel integral membrane protein that is predicted to be intrinsically disordered, i.e. that contains large segments whose native state is unstructured. We identified consortin as a binding partner of connexins, the building blocks of gap junctions. Consortin is located at the trans-Golgi network (TGN), in tubulovesicular transport organelles, and at the plasma membrane. It directly interacts with the TGN clathrin adaptors GGA1 and GGA2, and disruption of this interaction by expression of a consortin mutant lacking the acidic cluster-dileucine (DXXLL) GGA interaction motif causes an intracellular accumulation of several connexins. RNA interference-mediated silencing of consortin expression in HeLa cells blocks the cell surface targeting of these connexins, which accumulate intracellularly, whereas partial depletion and redistribution of the consortin pool slows down the intracellular degradation of gap junction plaques. Altogether, our results show that, by studying connexin trafficking, we have identified the first TGN cargo receptor for the targeting of transmembrane proteins to the plasma membrane. The identification of consortin provides in addition a potential target for therapies aimed at diseases in which connexin traffic is altered, including cardiac ischemia, peripheral neuropathies, cataracts and hearing impairment. Sequence accession numbers. GenBank: Human CNST cDNA, NM_152609; mouse Cnst cDNA, NM_146105.
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Brizard JP, Ramos J, Robert A, Lafitte D, Bigi N, Sarda P, Laoudj-Chenivesse D, Navarro F, Blanc P, Assenat E, Maurel P, Pascussi JM, Vilarem MJ. Identification of proteomic changes during human liver development by 2D-DIGE and mass spectrometry. J Hepatol 2009; 51:114-26. [PMID: 19443070 DOI: 10.1016/j.jhep.2009.02.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 02/06/2009] [Accepted: 02/18/2009] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS The aim of this study was to identify human liver proteins that are associated with different stages of liver development. METHODS We collected liver samples from 14 fetuses between 14 and 41 weeks of development, one child and four adults. Proteins which exhibited consistent and significant variations during development by two-dimensional differential in gel electrophoresis (2D-DIGE) were subjected to peptide mass fingerprint analysis by MALDI-TOF mass spectrometry. Real-time PCR analysis confirmed, at the transcriptional level, the data obtained by the proteomic approach. RESULTS Among a total of 80 protein spots showing differential expression, we identified 42 different proteins or polypeptide chains, of which 26 were upregulated and 16 downregulated in developing in comparison to adult liver. These proteins could be classified in specific groups according to their function. By comparing their temporal expression profiles, we identified protein groups that were associated with different developmental stages of human fetal liver and suggest that the changes in protein expression observed during the 20- to 36-week time window play a pivotal role in liver development. CONCLUSIONS The identification of these proteins may represent good markers of human liver and stem cells differentiation.
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Affiliation(s)
- Jean Paul Brizard
- Institut de Recherche pour le Développement, UMR 5096 (CNRS-IRD-Université Perpignan), Montpellier, France
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Belov GA, Feng Q, Nikovics K, Jackson CL, Ehrenfeld E. A critical role of a cellular membrane traffic protein in poliovirus RNA replication. PLoS Pathog 2008; 4:e1000216. [PMID: 19023417 PMCID: PMC2581890 DOI: 10.1371/journal.ppat.1000216] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 10/23/2008] [Indexed: 12/12/2022] Open
Abstract
Replication of many RNA viruses is accompanied by extensive remodeling of intracellular membranes. In poliovirus-infected cells, ER and Golgi stacks disappear, while new clusters of vesicle-like structures form sites for viral RNA synthesis. Virus replication is inhibited by brefeldin A (BFA), implicating some components(s) of the cellular secretory pathway in virus growth. Formation of characteristic vesicles induced by expression of viral proteins was not inhibited by BFA, but they were functionally deficient. GBF1, a guanine nucleotide exchange factor for the small cellular GTPases, Arf, is responsible for the sensitivity of virus infection to BFA, and is required for virus replication. Knockdown of GBF1 expression inhibited virus replication, which was rescued by catalytically active protein with an intact N-terminal sequence. We identified a mutation in GBF1 that allows growth of poliovirus in the presence of BFA. Interaction between GBF1 and viral protein 3A determined the outcome of infection in the presence of BFA.
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Affiliation(s)
- George A. Belov
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Qian Feng
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Krisztina Nikovics
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Catherine L. Jackson
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | - Ellie Ehrenfeld
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Chun J, Shapovalova Z, Dejgaard SY, Presley JF, Melançon P. Characterization of class I and II ADP-ribosylation factors (Arfs) in live cells: GDP-bound class II Arfs associate with the ER-Golgi intermediate compartment independently of GBF1. Mol Biol Cell 2008; 19:3488-500. [PMID: 18524849 DOI: 10.1091/mbc.e08-04-0373] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Despite extensive work on ADP-ribosylation factor (Arf) 1 at the Golgi complex, the functions of Arf2-5 in the secretory pathway, or for that of any Arf at the ER-Golgi intermediate compartment (ERGIC) remain uncharacterized. Here, we examined the recruitment of fluorescently tagged Arf1, -3, -4, and -5 onto peripheral ERGIC. Live cell imaging detected Arfs on peripheral puncta that also contained Golgi-specific brefeldin A (BFA) resistance factor (GBF) 1 and the ERGIC marker p58. Unexpectedly, BFA did not promote corecruitment of Arfs with GBF1 either at the Golgi complex or the ERGIC, but it uncovered striking differences between Arf1,3 and Arf4,5. Although Arf1,3 quickly dissociated from all endomembranes after BFA addition, Arf4,5 persisted on ERGIC structures, even after redistribution of GBF1 to separate compartments. The GDP-arrested Arf4(T31N) mutant localized to the ERGIC, even with BFA and Exo1 present. In addition, loss of Arf x GTP after treatment with Exo1 caused rapid release of all Arfs from the Golgi complex and led to GBF1 accumulation on both Golgi and ERGIC membranes. Our results demonstrate that GDP-bound Arf4,5 associate with ERGIC membranes through binding sites distinct from those responsible for GBF1 recruitment. Furthermore, they provide the first evidence that GBF1 accumulation on membranes may be caused by loss of Arf x GTP, rather than the formation of an Arf x GDP x BFA x GBF1 complex.
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Affiliation(s)
- Justin Chun
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
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Havrylov S, Ichioka F, Powell K, Borthwick EB, Baranska J, Maki M, Buchman VL. Adaptor Protein Ruk/CIN85 is Associated with a Subset of COPI-Coated Membranes of the Golgi Complex. Traffic 2008; 9:798-812. [DOI: 10.1111/j.1600-0854.2008.00724.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Aspergillus nidulans hypB encodes a Sec7-domain protein important for hyphal morphogenesis. Fungal Genet Biol 2008; 45:749-59. [DOI: 10.1016/j.fgb.2007.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 11/07/2007] [Accepted: 11/19/2007] [Indexed: 01/31/2023]
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Abstract
Intracellular trafficking of membrane-coated vesicles represents a fundamental process that controls the architecture of different intracellular compartments and communication between the cell and its environment. Major trafficking pathways consist of an inward flux of endocytic vesicles from the plasma membrane and an outward flux of exocytic vesicles to the plasma membrane. This overview describes a number of molecular biology tools commonly used to analyze endocytic and exocytic pathways. The overall emphasis is on major proteins responsible for vesicle formation, recognition, and fusion. These include components of vesicle coats, adaptor complexes, SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins, and Rab guanosine 5'-triphosphatases (GTPases), which represent attractive targets for genetic manipulation aimed at unraveling mechanisms of endocytosis and exocytosis.
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Affiliation(s)
- Elena V Vassilieva
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
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Coemans B, Takahashi Y, Berberich T, Ito A, Kanzaki H, Matsumura H, Saitoh H, Tsuda S, Kamoun S, Sági L, Swennen R, Terauchi R. High-throughput in planta expression screening identifies an ADP-ribosylation factor (ARF1) involved in non-host resistance and R gene-mediated resistance. MOLECULAR PLANT PATHOLOGY 2008; 9:25-36. [PMID: 18705881 PMCID: PMC6640410 DOI: 10.1111/j.1364-3703.2007.00440.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
To identify positive regulators of cell death in plants, we performed a high-throughput screening, employing potato virus X-based overexpression in planta of a cDNA library derived from paraquat-treated Nicotiana benthamiana leaves. The screening of 30,000 cDNA clones enabled the identification of an ADP-ribosylation factor 1 (ARF1) that induces cell death when overexpressed in N. benthamiana. Overexpression of the guanosine diphosphate (GDP)-locked mutant of ARF1 did not trigger cell death, suggesting that ARF1 guanosine triphosphatase (GTPase) activity is necessary for the observed cell death-inducing activity. The ARF1 transcript level increased strongly following treatment with Phytophthora infestans elicitor INF1, as well as inoculation with a non-host pathogen Pseudomonas cichorii in N. benthamiana. In addition, ARF1 was induced in the interaction between the N gene and tobacco mosaic virus (TMV) in Nicotiana tabacum. By contrast, inoculation with the virulent pathogen Pseudomonas syringae pv. tabaci did not affect ARF1 expression in N. benthamiana. Virus-induced gene silencing of ARF1 in N. benthamiana resulted in a stunted phenotype, and severely hampered non-host resistance towards P. cichorii. In addition, ARF1 silencing partially compromised resistance towards TMV in N. benthamiana containing the N resistance gene. By contrast, and in accordance with the ARF1 gene expression profile, silencing of ARF1 transcription did not alter the susceptibility of N. benthamiana towards the pathogen P. syringae pv. tabaci. These results strongly implicate ARF1 in the non-host resistance to bacteria and N gene-mediated resistance in N. benthamiana.
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Affiliation(s)
- Bert Coemans
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, Katholieke Universiteit Leuven, Kasteelpark Arenberg 13, 3001 Leuven, Belgium
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ARF1 is directly involved in dynamin-independent endocytosis. Nat Cell Biol 2007; 10:30-41. [PMID: 18084285 DOI: 10.1038/ncb1666] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Accepted: 11/29/2007] [Indexed: 12/20/2022]
Abstract
Endocytosis of glycosylphosphatidyl inositol (GPI)-anchored proteins (GPI-APs) and the fluid phase takes place primarily through a dynamin- and clathrin-independent, Cdc42-regulated pinocytic mechanism. This mechanism is mediated by primary carriers called clathrin-independent carriers (CLICs), which fuse to form tubular early endocytic compartments called GPI-AP enriched endosomal compartments (GEECs). Here, we show that reduction in activity or levels of ARF1 specifically inhibits GPI-AP and fluid-phase endocytosis without affecting other clathrin-dependent or independent endocytic pathways. ARF1 is activated at distinct sites on the plasma membrane, and by the recruitment of RhoGAP domain-containing protein, ARHGAP10, to the plasma membrane, modulates cell-surface Cdc42 dynamics. This results in the coupling of ARF1 and Cdc42 activity to regulate endocytosis at the plasma membrane. These findings provide a molecular basis for a crosstalk of endocytosis with secretion by the sharing of a key regulator of secretory traffic, ARF1.
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Haynes LP, Sherwood MW, Dolman NJ, Burgoyne RD. Specificity, promiscuity and localization of ARF protein interactions with NCS-1 and phosphatidylinositol-4 kinase-III beta. Traffic 2007; 8:1080-92. [PMID: 17555535 PMCID: PMC2492389 DOI: 10.1111/j.1600-0854.2007.00594.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ADP-ribosylation factor (ARF) proteins are involved in multiple intracellular vesicular transport pathways. Most studies have focused on the functions of ARF1 or ARF6 and little is known about the remaining ARF isoforms. Although the mammalian ARF proteins share a high degree of sequence identity, recent evidence has indicated that they may control distinct trafficking steps within cells. A unanswered issue is the degree of specificity of ARF family members for different interacting proteins. To investigate potential functional differences between the human ARF proteins, we have examined the localization of all human ARF isoforms and their interactions with two ARF1 binding proteins, neuronal calcium sensor-1 (NCS-1) and phosphatidylinositol-4 kinase-IIIbeta (PI4Kbeta). Use of a fluorescent protein fragment complementation method showed direct interactions between ARFs 1, 3, 5 and 6 with NCS-1 but at different intracellular locations in live HeLa cells. Photobleaching experiments indicated that complementation did not detect dynamic changes in protein interactions over short-time scales. A more specific interaction between ARFs 1/3 and PI4Kbeta was observed. Consistent with these latter findings ARF1 but not ARF5 or 6 enhanced the stimulatory effect of PI4Kbeta on regulated exocytosis, suggesting a specific role for class-I ARFs in the regulation of PI4Kbeta.
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Affiliation(s)
- Lee P Haynes
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Mark W. Sherwood
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Nick J Dolman
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
| | - Robert D Burgoyne
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK
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Matheson LA, Hanton SL, Rossi M, Latijnhouwers M, Stefano G, Renna L, Brandizzi F. Multiple roles of ADP-ribosylation factor 1 in plant cells include spatially regulated recruitment of coatomer and elements of the Golgi matrix. PLANT PHYSIOLOGY 2007; 143:1615-27. [PMID: 17307898 PMCID: PMC1851833 DOI: 10.1104/pp.106.094953] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Recent evidence indicates that ADP-ribosylation factor 1 (ARF1) carries out multiple roles in plant cells that may be independent from the established effector complex COPI. To investigate potential COPI-independent functions, we have followed the dynamics of ARF1 and a novel putative effector, the plant golgin GRIP-related ARF-binding domain-containing Arabidopsis (Arabidopsis thaliana) protein 1 (GDAP1) in living plant cells. We present data that ascribe a new role to ARF1 in plant cell membrane traffic by showing that the GTPase functions to recruit GDAP1 to membranes. In addition, although ARF1 appears to be central to the recruitment of both COPI components and the golgin, we have established a different subcellular distribution of these ARF1 effectors. Live cell imaging demonstrates that GDAP1 and COPI are distributed on Golgi membranes. However, GDAP1 is also found on ARF1-labeled structures that lack coatomer, suggesting that the membrane environment, rather than ARF1 alone, influences the differential recruitment of ARF1 effectors. In support of this hypothesis, fluorescence recovery after photobleaching analyses demonstrated that GDAP1 and COPI have different kinetics on membranes during the cycle of activation and inactivation of ARF1. Therefore, our data support a model where modulation of the cellular functions of ARF1 in plant cells encompasses not only the intrinsic activities of the effectors, but also differential recruitment onto membranes that is spatially regulated.
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Affiliation(s)
- Loren A Matheson
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
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Zhou C, Cunningham L, Marcus AI, Li Y, Kahn RA. Arl2 and Arl3 regulate different microtubule-dependent processes. Mol Biol Cell 2006; 17:2476-87. [PMID: 16525022 PMCID: PMC1446103 DOI: 10.1091/mbc.e05-10-0929] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Arl2 and Arl3 are closely related members of the Arf family of regulatory GTPases that arose from a common ancestor early in eukaryotic evolution yet retain extensive structural, biochemical, and functional features. The presence of Arl3 in centrosomes, mitotic spindles, midzones, midbodies, and cilia are all supportive of roles in microtubule-dependent processes. Knockdown of Arl3 by siRNA resulted in changes in cell morphology, increased acetylation of alpha-tubulin, failure of cytokinesis, and increased number of binucleated cells. We conclude that Arl3 binds microtubules in a regulated manner to alter specific aspects of cytokinesis. In contrast, an excess of Arl2 activity, achieved by expression of the [Q70L]Arl2 mutant, caused the loss of microtubules and cell cycle arrest in M phase. Initial characterization of the underlying defects suggests a defect in the ability to polymerize tubulin in the presence of excess Arl2 activity. We also show that Arl2 is present in centrosomes and propose that its action in regulating tubulin polymerization is mediated at centrosomes. Somewhat paradoxically, no phenotypes were observed Arl2 expression was knocked down or Arl3 activity was increased in HeLa cells. We conclude that Arl2 and Arl3 have related but distinct roles at centrosomes and in regulating microtubule-dependent processes.
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Affiliation(s)
- Chengjing Zhou
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-3050, USA
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Shin HW, Kobayashi H, Kitamura M, Waguri S, Suganuma T, Uchiyama Y, Nakayama K. Roles of ARFRP1 (ADP-ribosylation factor-related protein 1) in post-Golgi membrane trafficking. J Cell Sci 2005; 118:4039-48. [PMID: 16129887 DOI: 10.1242/jcs.02524] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ADP-ribosylation factor (ARF)-related protein 1 (ARFRP1) is a small GTPase with significant similarity to the ARF family. However, little is known about the function of ARFRP1 in mammalian cells, although knockout mice of its gene are embryonic lethal. In the present study, we demonstrate that ARFRP1 is associated mainly with the trans-Golgi compartment and the trans-Golgi network (TGN) and is an essential regulatory factor for targeting of Arl1 and GRIP domain-containing proteins, golgin-97 and golgin-245, onto Golgi membranes. Furthermore, we show that, in concert with Arl1 and GRIP proteins, ARFRP1 is implicated in the Golgi-to-plasma membrane transport of the vesicular stomatitis virus G protein as well as in the retrograde transport of TGN38 and Shiga toxin from endosomes to the TGN.
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Affiliation(s)
- Hye-Won Shin
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
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Latijnhouwers M, Hawes C, Carvalho C, Oparka K, Gillingham AK, Boevink P. An Arabidopsis GRIP domain protein locates to the trans-Golgi and binds the small GTPase ARL1. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 44:459-70. [PMID: 16236155 DOI: 10.1111/j.1365-313x.2005.02542.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
GRIP domain proteins are a class of golgins that have been described in yeast and animals. They locate to the trans-Golgi network and are thought to play a role in endosome-to-Golgi trafficking. The Arabidopsis GRIP domain protein, AtGRIP, fused to the green fluorescent protein (GFP), locates to Golgi stacks but does not exactly co-locate with the Golgi marker sialyl transferase (ST)-mRFP, nor with the t-SNAREs Memb11, SYP31 and BS14a. We conclude that the location of AtGRIP is further to the trans side of the stack than STtmd-mRFP. The 185-aa C-terminus of AtGRIP containing the GRIP domain targeted GFP to the Golgi, although a proportion of the fusion protein was still found in the cytosol. Mutation of a conserved tyrosine (Y717) to alanine in the GRIP domain disrupted Golgi localization. ARL1 is a small GTPase required for Golgi targeting of GRIP domain proteins in other systems. An Arabidopsis ARL1 homologue was isolated and shown to target to Golgi stacks. The GDP-restricted mutant of ARL1, AtARL1-T31N, was observed to locate partially to the cytosol, whereas the GTP-restricted mutant AtARL1-Q71L labelled the Golgi and a population of small structures. Increasing the levels of AtARL1 in epidermal cells increased the proportion of GRIP-GFP fusion protein on Golgi stacks. We show, moreover, that AtARL1 interacted with the GRIP domain in a GTP-dependent manner in vitro in affinity chromatography and in the yeast two-hybrid system. This indicates that AtGRIP and AtARL1 interact directly. We conclude that the pathway involving ARL1 and GRIP domain golgins is conserved in plants.
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Affiliation(s)
- Maita Latijnhouwers
- Cell-to-Cell Communication Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK
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Hasdemir B, Fitzgerald DJ, Prior IA, Tepikin AV, Burgoyne RD. Traffic of Kv4 K+ channels mediated by KChIP1 is via a novel post-ER vesicular pathway. ACTA ACUST UNITED AC 2005; 171:459-69. [PMID: 16260497 PMCID: PMC2171252 DOI: 10.1083/jcb.200506005] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The traffic of Kv4 K+ channels is regulated by the potassium channel interacting proteins (KChIPs). Kv4.2 expressed alone was not retained within the ER, but reached the Golgi complex. Coexpression of KChIP1 resulted in traffic of the channel to the plasma membrane, and traffic was abolished when mutations were introduced into the EF-hands with channel captured on vesicular structures that colocalized with KChIP1(2–4)-EYFP. The EF-hand mutant had no effect on general exocytic traffic. Traffic of Kv4.2 was coat protein complex I (COPI)–dependent, but KChIP1-containing vesicles were not COPII-coated, and expression of a GTP-loaded Sar1 mutant to block COPII function more effectively inhibited traffic of vesicular stomatitis virus glycoprotein (VSVG) than did KChIP1/Kv4.2 through the secretory pathway. Therefore, KChIP1seems to be targeted to post-ER transport vesicles, different from COPII-coated vesicles and those involved in traffic of VSVG. When expressed in hippocampal neurons, KChIP1 co-distributed with dendritic Golgi outposts; therefore, the KChIP1 pathway could play an important role in local vesicular traffic in neurons.
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Affiliation(s)
- Burcu Hasdemir
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, England, UK
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