1
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Griffiths G, Brügger B, Freund C. Lipid switches in the immunological synapse. J Biol Chem 2024; 300:107428. [PMID: 38823638 PMCID: PMC11259711 DOI: 10.1016/j.jbc.2024.107428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 05/07/2024] [Accepted: 05/26/2024] [Indexed: 06/03/2024] Open
Abstract
Adaptive immune responses comprise the activation of T cells by peptide antigens that are presented by proteins of the Major Histocompatibility Complex (MHC) on the surface of an antigen-presenting cell. As a consequence of the T cell receptor interacting productively with a certain peptide-MHC complex, a specialized cell-cell junction known as the immunological synapse forms and is accompanied by changes in the spatiotemporal patterning and function of intracellular signaling molecules. Key modifications occurring at the cytoplasmic leaflet of the plasma and internal membranes in activated T cells comprise lipid switches that affect the binding and distribution of proteins within or near the lipid bilayer. Here, we describe two major classes of lipid switches that act at this critical water/membrane interface. Phosphoinositides are derived from phosphatidylinositol, an amphiphilic molecule that contains two fatty acid chains and a phosphate group that bridges the glycerol backbone to the carbohydrate inositol. The inositol ring can be variably (de-)phosphorylated by dedicated kinases and phosphatases, thereby creating phosphoinositide signatures that define the composition and properties of signaling molecules, molecular complexes, or whole organelles. Palmitoylation refers to the reversible attachment of the fatty acid palmitate to a substrate protein's cysteine residue. DHHC enzymes, named after the four conserved amino acids in their active site, catalyze this post-translational modification and thereby change the distribution of proteins at, between, and within membranes. T cells utilize these two types of molecular switches to adjust their properties to an activation process that requires changes in motility, transport, secretion, and gene expression.
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Affiliation(s)
| | - Britta Brügger
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Christian Freund
- Laboratory of Protein Biochemistry, Institute of Chemistry & Biochemistry, Freie Universität Berlin, Berlin, Germany.
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2
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Jian F, Wang S, Tian R, Wang Y, Li C, Li Y, Wang S, Fang C, Ma C, Rong Y. The STX17-SNAP47-VAMP7/VAMP8 complex is the default SNARE complex mediating autophagosome-lysosome fusion. Cell Res 2024; 34:151-168. [PMID: 38182888 PMCID: PMC10837459 DOI: 10.1038/s41422-023-00916-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 12/11/2023] [Indexed: 01/07/2024] Open
Abstract
Autophagosome-lysosome fusion mediated by SNARE complexes is an essential step in autophagy. Two SNAP29-containing SNARE complexes have been extensively studied in starvation-induced bulk autophagy, while the relevant SNARE complexes in other types of autophagy occurring under non-starvation conditions have been overlooked. Here, we found that autophagosome-lysosome fusion in selective autophagy under non-starvation conditions does not require SNAP29-containing SNARE complexes, but requires the STX17-SNAP47-VAMP7/VAMP8 SNARE complex. Further, the STX17-SNAP47-VAMP7/VAMP8 SNARE complex also functions in starvation-induced autophagy. SNAP47 is recruited to autophagosomes following concurrent detection of ATG8s and PI(4,5)P2 via its Pleckstrin homology domain. By contrast, SNAP29-containing SNAREs are excluded from selective autophagy due to inactivation by O-GlcNAcylation under non-starvation conditions. These findings depict a previously unknown, default SNARE complex responsible for autophagosome-lysosome fusion in both selective and bulk autophagy, which could guide research and therapeutic development in autophagy-related diseases.
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Affiliation(s)
- Fenglei Jian
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shen Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Rui Tian
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yufen Wang
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chuangpeng Li
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yan Li
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shixuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chao Fang
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China.
| | - Yueguang Rong
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonostic Infectious Disease, Huazhong University of Science and Technology, Wuhan, Hubei, China.
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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3
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Gasparotto M, Dall’Ara E, Vacca M, Filippini F. VAMP7j: A Splice Variant of Human VAMP7 That Modulates Neurite Outgrowth by Regulating L1CAM Transport to the Plasma Membrane. Int J Mol Sci 2023; 24:17326. [PMID: 38139155 PMCID: PMC10743575 DOI: 10.3390/ijms242417326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
The vesicle-associated membrane protein 7 (VAMP7) is a SNARE protein of the longin family involved in a wide range of subcellular trafficking events, including neurite sprouting and elongation. The expression of the human gene SYBL1, encoding VAMP7, is finely regulated by alternative splicing. Among the minor isoforms identified so far, VAMP7j is the one most expressed and modulated in the human brain. Therefore, we focused on gaining functional evidence on VAMP7j, which lacks a functional SNARE motif but retains both the longin and transmembrane domains. In human SH-SY5Y cells, we found VAMP7j to modulate neuritogenesis by mediating transport of L1CAM toward the plasma membrane, in a fashion regulated by phosphorylation of the longin domain. VAMP7-mediated regulation of L1CAM trafficking seems at least to differentiate humans from rats, with VAMP7j CNS expression being restricted to primates, including humans. Since L1CAM is a central player in neuritogenesis and axon guidance, these findings suggest the species-specific splicing of SYBL1 is among the fine tuners of human neurodevelopmental complexity.
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Affiliation(s)
- Matteo Gasparotto
- Synthetic Biology and Biotechnology Unit, Department of Biology, University of Padua, Via U. Bassi 58/B, 35131 Padova, Italy; (M.G.); (E.D.)
| | - Elena Dall’Ara
- Synthetic Biology and Biotechnology Unit, Department of Biology, University of Padua, Via U. Bassi 58/B, 35131 Padova, Italy; (M.G.); (E.D.)
| | - Marcella Vacca
- Institute of Genetics and Biophysics “A. Buzzati Traverso”, Consiglio Nazionale delle Ricerche (CNR), Via Pietro Castellino, 111, 80131 Naples, Italy
| | - Francesco Filippini
- Synthetic Biology and Biotechnology Unit, Department of Biology, University of Padua, Via U. Bassi 58/B, 35131 Padova, Italy; (M.G.); (E.D.)
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4
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Ricardi MM, Wallmeroth N, Cermesoni C, Mehlhorn DG, Richter S, Zhang L, Mittendorf J, Godehardt I, Berendzen KW, von Roepenack-Lahaye E, Stierhof YD, Lipka V, Jürgens G, Grefen C. A tyrosine phospho-switch within the Longin domain of VAMP721 modulates SNARE functionality. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1633-1651. [PMID: 37659090 DOI: 10.1111/tpj.16451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 09/04/2023]
Abstract
The final step in secretion is membrane fusion facilitated by SNARE proteins that reside in opposite membranes. The formation of a trans-SNARE complex between one R and three Q coiled-coiled SNARE domains drives the final approach of the membranes providing the mechanical energy for fusion. Biological control of this mechanism is exerted by additional domains within some SNAREs. For example, the N-terminal Longin domain (LD) of R-SNAREs (also called Vesicle-associated membrane proteins, VAMPs) can fold back onto the SNARE domain blocking interaction with other cognate SNAREs. The LD may also determine the subcellular localization via interaction with other trafficking-related proteins. Here, we provide cell-biological and genetic evidence that phosphorylation of the Tyrosine57 residue regulates the functionality of VAMP721. We found that an aspartate mutation mimics phosphorylation, leading to protein instability and subsequent degradation in lytic vacuoles. The mutant SNARE also fails to rescue the defects of vamp721vamp722 loss-of-function lines in spite of its wildtype-like localization within the secretory pathway and the ability to interact with cognate SNARE partners. Most importantly, it imposes a dominant negative phenotype interfering with root growth, normal secretion and cytokinesis in wildtype plants generating large aggregates that mainly contain secretory vesicles. Non-phosphorylatable VAMP721Y57F needs higher gene dosage to rescue double mutants in comparison to native VAMP721 underpinning that phosphorylation modulates SNARE function. We propose a model where short-lived phosphorylation of Y57 serves as a regulatory step to control VAMP721 activity, favoring its open state and interaction with cognate partners to ultimately drive membrane fusion.
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Affiliation(s)
- Martiniano Maria Ricardi
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Bochum, Germany
- Departamento de Fisiología y Biología Molecular y Celular (FBMC), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Niklas Wallmeroth
- University of Tübingen, ZMBP Developmental Genetics, Tübingen, Germany
| | - Cecilia Cermesoni
- Departamento de Fisiología y Biología Molecular y Celular (FBMC), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Sandra Richter
- University of Tübingen, ZMBP Developmental Genetics, Tübingen, Germany
- University of Tübingen, ZMBP Central Facilities, Tübingen, Germany
| | - Lei Zhang
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Bochum, Germany
| | - Josephine Mittendorf
- University of Göttingen, Albrecht-von-Haller-Institute of Plant Sciences, Göttingen, Germany
| | - Ingeborg Godehardt
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Bochum, Germany
| | | | | | | | - Volker Lipka
- University of Göttingen, Albrecht-von-Haller-Institute of Plant Sciences, Göttingen, Germany
| | - Gerd Jürgens
- University of Tübingen, ZMBP Developmental Genetics, Tübingen, Germany
| | - Christopher Grefen
- Ruhr University Bochum, Faculty of Biology and Biotechnology, Bochum, Germany
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5
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Vats S, Galli T. Role of SNAREs in Unconventional Secretion—Focus on the VAMP7-Dependent Secretion. Front Cell Dev Biol 2022; 10:884020. [PMID: 35784483 PMCID: PMC9244844 DOI: 10.3389/fcell.2022.884020] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/27/2022] [Indexed: 11/28/2022] Open
Abstract
Intracellular membrane protein trafficking is crucial for both normal cellular physiology and cell-cell communication. The conventional secretory route follows transport from the Endoplasmic reticulum (ER) to the plasma membrane via the Golgi apparatus. Alternative modes of secretion which can bypass the need for passage through the Golgi apparatus have been collectively termed as Unconventional protein secretion (UPS). UPS can comprise of cargo without a signal peptide or proteins which escape the Golgi in spite of entering the ER. UPS has been classified further depending on the mode of transport. Type I and Type II unconventional secretion are non-vesicular and non-SNARE protein dependent whereas Type III and Type IV dependent on vesicles and on SNARE proteins. In this review, we focus on the Type III UPS which involves the import of cytoplasmic proteins in membrane carriers of autophagosomal/endosomal origin and release in the extracellular space following SNARE-dependent intracellular membrane fusion. We discuss the role of vesicular SNAREs with a strong focus on VAMP7, a vesicular SNARE involved in exosome, lysosome and autophagy mediated secretion. We further extend our discussion to the role of unconventional secretion in health and disease with emphasis on cancer and neurodegeneration.
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Affiliation(s)
- Somya Vats
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Membrane Traffic in Healthy and Diseased Brain, Université Paris Cité, Paris, France
| | - Thierry Galli
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Membrane Traffic in Healthy and Diseased Brain, Université Paris Cité, Paris, France
- GHU PARIS Psychiatrie & Neurosciences, Paris, France
- *Correspondence: Thierry Galli,
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6
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Gasparotto M, Lee YS, Palazzi A, Vacca M, Filippini F. Nuclear and Cytoplasmatic Players in Mitochondria-Related CNS Disorders: Chromatin Modifications and Subcellular Trafficking. Biomolecules 2022; 12:biom12050625. [PMID: 35625553 PMCID: PMC9138954 DOI: 10.3390/biom12050625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 12/10/2022] Open
Abstract
Aberrant mitochondrial phenotypes are common to many central nervous system (CNS) disorders, including neurodegenerative and neurodevelopmental diseases. Mitochondrial function and homeostasis depend on proper control of several biological processes such as chromatin remodeling and transcriptional control, post-transcriptional events, vesicle and organelle subcellular trafficking, fusion, and morphogenesis. Mutation or impaired regulation of major players that orchestrate such processes can disrupt cellular and mitochondrial dynamics, contributing to neurological disorders. The first part of this review provides an overview of a functional relationship between chromatin players and mitochondria. Specifically, we relied on specific monogenic CNS disorders which share features with mitochondrial diseases. On the other hand, subcellular trafficking is coordinated directly or indirectly through evolutionarily conserved domains and proteins that regulate the dynamics of membrane compartments and organelles, including mitochondria. Among these “building blocks”, longin domains and small GTPases are involved in autophagy and mitophagy, cell reshaping, and organelle fusion. Impairments in those processes significantly impact CNS as well and are discussed in the second part of the review. Hopefully, in filling the functional gap between the nucleus and cytoplasmic organelles new routes for therapy could be disclosed.
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Affiliation(s)
- Matteo Gasparotto
- Synthetic Biology and Biotechnology Unit, Department of Biology, University of Padua, Via Ugo Bassi 58/B, 35131 Padua, Italy;
| | - Yi-Shin Lee
- Institute of Genetics and Biophysics “A. Buzzati Traverso”, CNR, Via Pietro Castellino, 111, 80131 Naples, Italy; (Y.-S.L.); (A.P.); (M.V.)
- Pharmacology Division, Department of Neuroscience, Reproductive and Odontostomatological Sciences, Faculty of Medicine and surgery, University of Naples Federico II, Via Pansini 5, Building 19 (Biological Tower), 80131 Naples, Italy
| | - Alessandra Palazzi
- Institute of Genetics and Biophysics “A. Buzzati Traverso”, CNR, Via Pietro Castellino, 111, 80131 Naples, Italy; (Y.-S.L.); (A.P.); (M.V.)
| | - Marcella Vacca
- Institute of Genetics and Biophysics “A. Buzzati Traverso”, CNR, Via Pietro Castellino, 111, 80131 Naples, Italy; (Y.-S.L.); (A.P.); (M.V.)
| | - Francesco Filippini
- Synthetic Biology and Biotechnology Unit, Department of Biology, University of Padua, Via Ugo Bassi 58/B, 35131 Padua, Italy;
- Correspondence:
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7
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Tian X, Teng J, Chen J. New insights regarding SNARE proteins in autophagosome-lysosome fusion. Autophagy 2021; 17:2680-2688. [PMID: 32924745 PMCID: PMC8525925 DOI: 10.1080/15548627.2020.1823124] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/04/2020] [Accepted: 09/09/2020] [Indexed: 12/26/2022] Open
Abstract
Macroautophagy/autophagy refers to the engulfment of cellular contents selected for lysosomal degradation. The final step in autophagy is the fusion of autophagosome with the lysosome, which is mediated by SNARE proteins. Of the SNAREs, autophagosome-localized Q-SNAREs, such as STX17 and SNAP29, and lysosome-localized R-SNAREs, such as VAMP8 or VAMP7, have been reported to be involved. Recent studies also reveal participation of the R-SNARE, YKT6, in autophagosome-lysosome fusion. These SNAREs, with the help of other regulatory factors, act coordinately to spatiotemporally control the fusion process. Besides regulating autophagosome-lysosome fusion, some SNAREs, such as STX17, also function in other autophagic processes, including autophagosome formation and mitophagy. A better understanding of the functions of SNAREs will shed light on the molecular mechanisms of autophagosome-lysosome fusion as well as on the mechanisms by which autophagy is globally regulated.Abbreviations: ATG: autophagy related; DNM1L: dynamin 1 like; ER: endoplasmic reticulum; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor associated protein like 1; IRGM: immunity related GTPase M; LAMP2: lysosomal associated membrane protein 2; MAP1LC3B/LC3: microtubule associated protein 1 light chain 3 beta; MTOR: mechanistic target of rapamycin kinase; PIK3R4: phosphoinositide-3-kinase regulatory subunit 4; PLEKHM1: pleckstrin homology and RUN domain containing M1; PRKN: PRKN RBR E3 ubiquitin protein ligase; RAB2A: RAB2A, member RAS oncogene family; RAB33B: RAB33B, member RAS oncogene family; RAB7A: RAB7A, member RAS oncogene family; RB1CC1: RB1 inducible coiled-coil 1; RTN3: reticulon 3; RUBCNL: rubicon like autophagy enhancer; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SNAP29: synaptosomal associated protein 29; STX17: syntaxin 17; ULK1: unc-51 like autophagy activating kinase 1; VAMP7: vesicle associated membrane protein 7; VAMP8: vesicle associated membrane protein 8; YKT6: YKT6 v-SNARE homolog.
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Affiliation(s)
- Xiaoyu Tian
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Junlin Teng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Jianguo Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
- Center for Quantitative Biology, Peking University, Beijing, China
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8
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Bowman SL, Le L, Zhu Y, Harper DC, Sitaram A, Theos AC, Sviderskaya EV, Bennett DC, Raposo-Benedetti G, Owen DJ, Dennis MK, Marks MS. A BLOC-1-AP-3 super-complex sorts a cis-SNARE complex into endosome-derived tubular transport carriers. J Cell Biol 2021; 220:212016. [PMID: 33886957 PMCID: PMC8077166 DOI: 10.1083/jcb.202005173] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 02/15/2021] [Accepted: 03/19/2021] [Indexed: 02/02/2023] Open
Abstract
Membrane transport carriers fuse with target membranes through engagement of cognate vSNAREs and tSNAREs on each membrane. How vSNAREs are sorted into transport carriers is incompletely understood. Here we show that VAMP7, the vSNARE for fusing endosome-derived tubular transport carriers with maturing melanosomes in melanocytes, is sorted into transport carriers in complex with the tSNARE component STX13. Sorting requires either recognition of VAMP7 by the AP-3δ subunit of AP-3 or of STX13 by the pallidin subunit of BLOC-1, but not both. Consequently, melanocytes expressing both AP-3δ and pallidin variants that cannot bind their respective SNARE proteins are hypopigmented and fail to sort BLOC-1-dependent cargo, STX13, or VAMP7 into transport carriers. However, SNARE binding does not influence BLOC-1 function in generating tubular transport carriers. These data reveal a novel mechanism of vSNARE sorting by recognition of redundant sorting determinants on a SNARE complex by an AP-3-BLOC-1 super-complex.
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Affiliation(s)
- Shanna L. Bowman
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Department of Biology, Linfield University, McMinnville, OR
| | - Linh Le
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA
| | - Yueyao Zhu
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Department of Biology, University of Pennsylvania, Philadelphia, PA
| | - Dawn C. Harper
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA
| | - Anand Sitaram
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA
| | | | - Elena V. Sviderskaya
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, UK
| | - Dorothy C. Bennett
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, UK
| | - Graça Raposo-Benedetti
- Institut Curie, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique Unité Mixte de Recherche 144, Compartiments de Structure et de Membrane, Paris, France
| | - David J. Owen
- Cambridge Institute for Medical Research, Cambridge, UK
| | - Megan K. Dennis
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Department of Biology, Marist College, Poughkeepsie, NY
| | - Michael S. Marks
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Correspondence to Michael S. Marks:
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9
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Deretic D, Lorentzen E, Fresquez T. The ins and outs of the Arf4-based ciliary membrane-targeting complex. Small GTPases 2021; 12:1-12. [PMID: 31068062 PMCID: PMC7781591 DOI: 10.1080/21541248.2019.1616355] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/09/2019] [Accepted: 05/02/2019] [Indexed: 10/26/2022] Open
Abstract
The small GTPase Arf4-based ciliary membrane-targeting complex recognizes specific targeting signals within sensory receptors and regulates their directed movement to primary cilia. Activated Arf4 directly binds the VxPx ciliary-targeting signal (CTS) of the light-sensing receptor rhodopsin. Recent findings revealed that at the trans-Golgi, marked by the small GTPase Rab6, activated Arf4 forms a functional complex with rhodopsin and the Arf guanine nucleotide exchange factor (GEF) GBF1, providing positive feedback that drives further Arf4 activation in ciliary trafficking. Arf4 function is conserved across diverse cell types; however, it appears that not all its aspects are conserved across species, as mouse Arf4 is a natural mutant in the conserved α3 helix, which is essential for its interaction with rhodopsin. Generally, activated Arf4 regulates the assembly of the targeting nexus containing the Arf GAP ASAP1 and the Rab11a-FIP3-Rabin8 dual effector complex, which controls the assembly of the highly conserved Rab11a-Rabin8-Rab8 ciliary-targeting module. It was recently found that this module interacts with the R-SNARE VAMP7, likely in its activated, c-Src-phosphorylated form. Rab11 and Rab8 bind VAMP7 regulatory longin domain (LD), whereas Rabin8 interacts with the SNARE domain, capturing VAMP7 for delivery to the ciliary base and subsequent pairing with the cognate SNAREs syntaxin 3 and SNAP-25. This review will focus on the implications of these novel findings that further illuminate the role of well-ordered Arf and Rab interaction networks in targeting of sensory receptors to primary cilia. Abbreviations: CTS: Ciliary-Targeting Signal; GAP: GTPase Activating Protein; GEF: Guanine Nucleotide Exchange Factor; RTC(s), Rhodopsin Transport Carrier(s); SNARE: Soluble N-ethylmaleimide-sensitive Factor Attachment Protein Receptor; TGN: Trans-Golgi Network.
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Affiliation(s)
- Dusanka Deretic
- Departments of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM, USA
- Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, USA
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Theresa Fresquez
- Departments of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM, USA
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10
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Tang BL. SNAREs and developmental disorders. J Cell Physiol 2020; 236:2482-2504. [PMID: 32959907 DOI: 10.1002/jcp.30067] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/20/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022]
Abstract
Members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family mediate membrane fusion processes associated with vesicular trafficking and autophagy. SNAREs mediate core membrane fusion processes essential for all cells, but some SNAREs serve cell/tissue type-specific exocytic/endocytic functions, and are therefore critical for various aspects of embryonic development. Mutations or variants of their encoding genes could give rise to developmental disorders, such as those affecting the nervous system and immune system in humans. Mutations to components in the canonical synaptic vesicle fusion SNARE complex (VAMP2, STX1A/B, and SNAP25) and a key regulator of SNARE complex formation MUNC18-1, produce variant phenotypes of autism, intellectual disability, movement disorders, and epilepsy. STX11 and MUNC18-2 mutations underlie 2 subtypes of familial hemophagocytic lymphohistiocytosis. STX3 mutations contribute to variant microvillus inclusion disease. Chromosomal microdeletions involving STX16 play a role in pseudohypoparathyroidism type IB associated with abnormal imprinting of the GNAS complex locus. In this short review, I discuss these and other SNARE gene mutations and variants that are known to be associated with a variety developmental disorders, with a focus on their underlying cellular and molecular pathological basis deciphered through disease modeling. Possible pathogenic potentials of other SNAREs whose variants could be disease predisposing are also speculated upon.
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Affiliation(s)
- Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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11
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Chitirala P, Ravichandran K, Galgano D, Sleiman M, Krause E, Bryceson YT, Rettig J. Cytotoxic Granule Exocytosis From Human Cytotoxic T Lymphocytes Is Mediated by VAMP7. Front Immunol 2019; 10:1855. [PMID: 31447853 PMCID: PMC6692471 DOI: 10.3389/fimmu.2019.01855] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 07/23/2019] [Indexed: 11/13/2022] Open
Abstract
Cytotoxic T lymphocytes kill infected or malignant cells through the directed release of cytotoxic substances at the site of target cell contact, the immunological synapse. While genetic association studies of genes predisposing to early-onset life-threatening hemophagocytic lymphohistiocytosis has identified components of the plasma membrane fusion machinery, the identity of the vesicular components remain enigmatic. Here, we identify VAMP7 as an essential component of the vesicular fusion machinery of primary, human T cells. VAMP7 co-localizes with granule markers throughout all stages of T cell maturation and simultaneously fuses with granule markers at the IS. Knock-down of VAMP7 expression significantly decreased the killing efficiency of T cells, without diminishing early T cell receptor signaling. VAMP7 exerts its function in a SNARE complex with Syntaxin11 and SNAP-23 on the plasma membrane. The identification of the minimal fusion machinery in T cells provides a starting point for the development of potential drugs in immunotherapy.
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Affiliation(s)
- Praneeth Chitirala
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Donatella Galgano
- Center for Hematology and Regenerative Medicine (HERM), Karolinska Institute, Stockholm, Sweden
| | - Marwa Sleiman
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Yenan T. Bryceson
- Center for Hematology and Regenerative Medicine (HERM), Karolinska Institute, Stockholm, Sweden
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
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12
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Tian X, Zheng P, Zhou C, Wang X, Ma H, Ma W, Zhou X, Teng J, Chen J. DIPK2A promotes STX17- and VAMP7-mediated autophagosome-lysosome fusion by binding to VAMP7B. Autophagy 2019; 16:797-810. [PMID: 31251111 DOI: 10.1080/15548627.2019.1637199] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Autophagosome and lysosome fusion is an important macroautophagy/autophagy process for cargo degradation, and SNARE proteins, including STX17, SNAP29, VAMP7 and VAMP8, are key players in this process. However, the manner in which this process is precisely regulated is poorly understood. Here, we show that VAMP7B, a SNARE domain-disrupted isoform of R-SNARE protein VAMP7, competes with SNARE domain functional isoform VAMP7A to bind to STX17 and inhibits autophagosome-lysosome fusion. Moreover, we show that DIPK2A, a late endosome- and lysosome-localized protein, binds to VAMP7B, which inhibits the interaction of VAMP7B with STX17 and enhances the binding of STX17 to VAMP7A, thus enhancing autophagosome-lysosome fusion. Furthermore, DIPK2A participates in autophagic degradation of mitochondria proteins and alleviates apoptosis. Thus, we reveal a new aspect of autophagosome-lysosome fusion in which different isoforms of VAMP7 compete with STX17 and their regulation by DIPK2A.Abbreviations: DIPK2A: divergent protein kinase domain 2A; EEA1: early endosome antigen 1; GOLGA2: golgin A2; LAMP1: lysosomal associated membrane protein 1; MAP1LC3B/LC3: microtubule associated protein 1 light chain 3 beta; MFN2: mitofusin 2; MT-CO2: mitochondrially encoded cytochrome c oxidase II; PARP1: poly(ADP-ribose) polymerase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; RAB5A: RAB5A, member RAS oncogene family; RAB7A: RAB7A, member RAS oncogene family; REEP: receptor accessory protein; RTN4: reticulon 4; SNARE: SNAP receptor; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TOMM20: translocase of outer mitochondrial membrane 20; VAMP7: vesicle associated membrane protein 7; VAMP8: vesicle associated membrane protein 8.
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Affiliation(s)
- Xiaoyu Tian
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Pengli Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Chenqian Zhou
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Xurui Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Hua Ma
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou, China
| | - Wei Ma
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou, China
| | - Xiaokai Zhou
- Gansu Tech Innovation Center of Animal Cell, Biomedical Research Center, Northwest Minzu University, Lanzhou, China
| | - Junlin Teng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Jianguo Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China.,Center for Quantitative Biology, Peking University, Beijing, China
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Kandachar V, Tam BM, Moritz OL, Deretic D. An interaction network between the SNARE VAMP7 and Rab GTPases within a ciliary membrane-targeting complex. J Cell Sci 2018; 131:jcs.222034. [PMID: 30404838 DOI: 10.1242/jcs.222034] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/30/2018] [Indexed: 12/16/2022] Open
Abstract
The Arf4-rhodopsin complex (mediated by the VxPx motif in rhodopsin) initiates expansion of vertebrate rod photoreceptor cilia-derived light-sensing organelles through stepwise assembly of a conserved trafficking network. Here, we examine its role in the sorting of VAMP7 (also known as TI-VAMP) - an R-SNARE possessing a regulatory longin domain (LD) - into rhodopsin transport carriers (RTCs). During RTC formation and trafficking, VAMP7 colocalizes with the ciliary cargo rhodopsin and interacts with the Rab11-Rabin8-Rab8 trafficking module. Rab11 and Rab8 bind the VAMP7 LD, whereas Rabin8 (also known as RAB3IP) interacts with the SNARE domain. The Arf/Rab11 effector FIP3 (also known as RAB11FIP3) regulates VAMP7 access to Rab11. At the ciliary base, VAMP7 forms a complex with the cognate SNAREs syntaxin 3 and SNAP-25. When expressed in transgenic animals, a GFP-VAMP7ΔLD fusion protein and a Y45E phosphomimetic mutant colocalize with endogenous VAMP7. The GFP-VAMP7-R150E mutant displays considerable localization defects that imply an important role of the R-SNARE motif in intracellular trafficking, rather than cognate SNARE pairing. Our study defines the link between VAMP7 and the ciliary targeting nexus that is conserved across diverse cell types, and contributes to general understanding of how functional Arf and Rab networks assemble SNAREs in membrane trafficking.
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Affiliation(s)
- Vasundhara Kandachar
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Beatrice M Tam
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC V5Z 3N9, Canada
| | - Orson L Moritz
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC V5Z 3N9, Canada
| | - Dusanka Deretic
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM 87131, USA .,Cell Biology and Physiology, University of New Mexico, Albuquerque, NM 87131, USA
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Wu S, Wang D, Weng J, Liu J, Wang W. A revisit of the conformational dynamics of SNARE protein rYkt6. Biochem Biophys Res Commun 2018; 503:2841-2847. [PMID: 30119892 DOI: 10.1016/j.bbrc.2018.08.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 08/06/2018] [Indexed: 12/12/2022]
Abstract
N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are involved in the fusion of vesicles with their target membranes. R-SNARE protein Ykt6 is one of the most conserved SNARE in eukaryotes. The conformational state of Ykt6 is regulated by the lipidations at its C-terminal motif. Previous studies show that the binding of dodecylphosphocholine (DPC) can stabilize a closed conformation of rat Ykt6 (rYkt6) and mimic the farnesylated rYkt6. Despite this model, the detailed conformational dynamics of Ykt6 is still unclear. Here, we combined smFRET and MD simulation to demonstrate that the un-lipidated rYkt6 adopts five major conformational states. DPC binding shifts the conformational distribution toward the more closed states. At the same time, there remain considerable fractions of open and semi-open conformations in the presence of DPC. These newly revealed dynamic features of rYkt6 are consistent with its unique functional diversity in neuronal cells.
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Affiliation(s)
- Shaowen Wu
- Multiscale Research Institute of Complex Systems, Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, PR China
| | - Dongdong Wang
- Multiscale Research Institute of Complex Systems, Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, PR China
| | - Jingwei Weng
- Multiscale Research Institute of Complex Systems, Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, PR China
| | - Jianwei Liu
- Multiscale Research Institute of Complex Systems, Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, PR China.
| | - Wenning Wang
- Multiscale Research Institute of Complex Systems, Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai, PR China.
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15
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Chanaday NL, Kavalali ET. Presynaptic origins of distinct modes of neurotransmitter release. Curr Opin Neurobiol 2018; 51:119-126. [PMID: 29597140 PMCID: PMC6066415 DOI: 10.1016/j.conb.2018.03.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/22/2018] [Accepted: 03/12/2018] [Indexed: 11/17/2022]
Abstract
Presynaptic nerve terminals release neurotransmitter synchronously, asynchronously or spontaneously. During synchronous neurotransmission release is precisely coupled to action potentials, in contrast, asynchronous release events show only loose temporal coupling to presynaptic activity whereas spontaneous neurotransmission occurs independent of presynaptic activity. The mechanisms that give rise to this diversity in neurotransmitter release modes are poorly understood. Recent studies have described several presynaptic molecular pathways controlling synaptic vesicle pool segregation and recycling, which in turn may dictate distinct modes of neurotransmitter release. In this article, we review this recent work regarding neurotransmitter release modes and their relationship to synaptic vesicle pool dynamics as well as the molecular machinery that establishes synaptic vesicle pool identity.
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Affiliation(s)
- Natali L Chanaday
- Department of Neuroscience, the University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Ege T Kavalali
- Department of Neuroscience, the University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
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16
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Zhang B, Karnik R, Waghmare S, Donald N, Blatt MR. VAMP721 Conformations Unmask an Extended Motif for K+ Channel Binding and Gating Control. PLANT PHYSIOLOGY 2017; 173:536-551. [PMID: 27821719 PMCID: PMC5210753 DOI: 10.1104/pp.16.01549] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/04/2016] [Indexed: 05/20/2023]
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins play a major role in membrane fusion and contribute to cell expansion, signaling, and polar growth in plants. The SNARE SYP121 of Arabidopsis thaliana that facilitates vesicle fusion at the plasma membrane also binds with, and regulates, K+ channels already present at the plasma membrane to affect K+ uptake and K+-dependent growth. Here, we report that its cognate partner VAMP721, which assembles with SYP121 to drive membrane fusion, binds to the KAT1 K+ channel via two sites on the protein, only one of which contributes to channel-gating control. Binding to the VAMP721 SNARE domain suppressed channel gating. By contrast, interaction with the amino-terminal longin domain conferred specificity on VAMP721 binding without influencing gating. Channel binding was defined by a linear motif within the longin domain. The SNARE domain is thought to wrap around this structure when not assembled with SYP121 in the SNARE complex. Fluorescence lifetime analysis showed that mutations within this motif, which suppressed channel binding and its effects on gating, also altered the conformational displacement between the VAMP721 SNARE and longin domains. The presence of these two channel-binding sites on VAMP721, one also required for SNARE complex assembly, implies a well-defined sequence of events coordinating K+ uptake and the final stages of vesicle traffic. It suggests that binding begins with VAMP721, and subsequently with SYP121, thereby coordinating K+ channel gating during SNARE assembly and vesicle fusion. Thus, our findings also are consistent with the idea that the K+ channels are nucleation points for SNARE complex assembly.
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Affiliation(s)
- Ben Zhang
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Rucha Karnik
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Sakharam Waghmare
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Naomi Donald
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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17
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de Marcos Lousa C, Soubeyrand E, Bolognese P, Wattelet-Boyer V, Bouyssou G, Marais C, Boutté Y, Filippini F, Moreau P. Subcellular localization and trafficking of phytolongins (non-SNARE longins) in the plant secretory pathway. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2627-2639. [PMID: 26962210 PMCID: PMC4861013 DOI: 10.1093/jxb/erw094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
SNARE proteins are central elements of the machinery involved in membrane fusion of eukaryotic cells. In animals and plants, SNAREs have diversified to sustain a variety of specific functions. In animals, R-SNARE proteins called brevins have diversified; in contrast, in plants, the R-SNARE proteins named longins have diversified. Recently, a new subfamily of four longins named 'phytolongins' (Phyl) was discovered. One intriguing aspect of Phyl proteins is the lack of the typical SNARE motif, which is replaced by another domain termed the 'Phyl domain'. Phytolongins have a rather ubiquitous tissue expression in Arabidopsis but still await intracellular characterization. In this study, we found that the four phytolongins are distributed along the secretory pathway. While Phyl2.1 and Phyl2.2 are strictly located at the endoplasmic reticulum network, Phyl1.2 associates with the Golgi bodies, and Phyl1.1 locates mainly at the plasma membrane and partially in the Golgi bodies and post-Golgi compartments. Our results show that export of Phyl1.1 from the endoplasmic reticulum depends on the GTPase Sar1, the Sar1 guanine nucleotide exchange factor Sec12, and the SNAREs Sec22 and Memb11. In addition, we have identified the Y48F49 motif as being critical for the exit of Phyl1.1 from the endoplasmic reticulum. Our results provide the first characterization of the subcellular localization of the phytolongins, and we discuss their potential role in regulating the secretory pathway.
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Affiliation(s)
- Carine de Marcos Lousa
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK Faculty of Clinical and Applied Sciences, School of Biomedical Sciences, Leeds Beckett University, Portland Building 611, Leeds Beckett University City Campus, LS1 3HE, Leeds, UK
| | - Eric Soubeyrand
- CNRS-University of Bordeaux, UMR 5200 Membrane Biogenesis Laboratory, INRA Bordeaux Aquitaine, 71 Avenue Edouard Bourlaux, CS 20032, 33140 Villenave d'Ornon, France
| | - Paolo Bolognese
- Molecular Biology and Bioinformatics Unit, Department of Biology, University of Padova, Viale G. Colombo 3, 35131 Padova, Italy
| | - Valerie Wattelet-Boyer
- CNRS-University of Bordeaux, UMR 5200 Membrane Biogenesis Laboratory, INRA Bordeaux Aquitaine, 71 Avenue Edouard Bourlaux, CS 20032, 33140 Villenave d'Ornon, France
| | - Guillaume Bouyssou
- CNRS-University of Bordeaux, UMR 5200 Membrane Biogenesis Laboratory, INRA Bordeaux Aquitaine, 71 Avenue Edouard Bourlaux, CS 20032, 33140 Villenave d'Ornon, France
| | - Claireline Marais
- CNRS-University of Bordeaux, UMR 5200 Membrane Biogenesis Laboratory, INRA Bordeaux Aquitaine, 71 Avenue Edouard Bourlaux, CS 20032, 33140 Villenave d'Ornon, France
| | - Yohann Boutté
- CNRS-University of Bordeaux, UMR 5200 Membrane Biogenesis Laboratory, INRA Bordeaux Aquitaine, 71 Avenue Edouard Bourlaux, CS 20032, 33140 Villenave d'Ornon, France
| | - Francesco Filippini
- Molecular Biology and Bioinformatics Unit, Department of Biology, University of Padova, Viale G. Colombo 3, 35131 Padova, Italy
| | - Patrick Moreau
- CNRS-University of Bordeaux, UMR 5200 Membrane Biogenesis Laboratory, INRA Bordeaux Aquitaine, 71 Avenue Edouard Bourlaux, CS 20032, 33140 Villenave d'Ornon, France Bordeaux Imaging Center, UMS 3420 CNRS, US004 INSERM, University of Bordeaux, 33000 Bordeaux, France
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18
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Ghosh D, Pinto S, Danglot L, Vandewauw I, Segal A, Van Ranst N, Benoit M, Janssens A, Vennekens R, Vanden Berghe P, Galli T, Vriens J, Voets T. VAMP7 regulates constitutive membrane incorporation of the cold-activated channel TRPM8. Nat Commun 2016; 7:10489. [PMID: 26843440 PMCID: PMC4742910 DOI: 10.1038/ncomms10489] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 12/18/2015] [Indexed: 02/06/2023] Open
Abstract
The cation channel TRPM8 plays a central role in the somatosensory system, as a key sensor of innocuously cold temperatures and cooling agents. Although increased functional expression of TRPM8 has been implicated in various forms of pathological cold hypersensitivity, little is known about the cellular and molecular mechanisms that determine TRPM8 abundance at the plasma membrane. Here we demonstrate constitutive transport of TRPM8 towards the plasma membrane in atypical, non-acidic transport vesicles that contain lysosomal-associated membrane protein 1 (LAMP1), and provide evidence that vesicle-associated membrane protein 7 (VAMP7) mediates fusion of these vesicles with the plasma membrane. In line herewith, VAMP7-deficient mice exhibit reduced functional expression of TRPM8 in sensory neurons and concomitant deficits in cold avoidance and icilin-induced cold hypersensitivity. Our results uncover a cellular pathway that controls functional plasma membrane incorporation of a temperature-sensitive TRP channel, and thus regulates thermosensitivity in vivo.
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Affiliation(s)
- Debapriya Ghosh
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Silvia Pinto
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Lydia Danglot
- Institut Jacques Monod, CNRS UMR 7592, University of Paris Diderot, F-75013 Paris, France
- INSERM ERL U950, Membrane Traffic in Health & disease Group, F-75013 Paris, France
| | - Ine Vandewauw
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Andrei Segal
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Nele Van Ranst
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Melissa Benoit
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Annelies Janssens
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Rudi Vennekens
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience, Department of Clinical and Experimental Medicine, University of Leuven, B-3000 Leuven, Belgium
- Translational Research Centre for Gastrointestinal Disorders, KU Leuven, Herestraat 49 box 701, B-3000 Leuven, Belgium
| | - Thierry Galli
- Institut Jacques Monod, CNRS UMR 7592, University of Paris Diderot, F-75013 Paris, France
- INSERM ERL U950, Membrane Traffic in Health & disease Group, F-75013 Paris, France
| | - Joris Vriens
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
- Laboratory of Experimental Gynaecology, Department of Development and Regeneration, University of Leuven, Herestraat 49 box 611, B-3000 Leuven, Belgium
| | - Thomas Voets
- Laboratory of Ion Channel Research and TRP Channel Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, University of Leuven, Herestraat 49 box 802, B-3000 Leuven, Belgium
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Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins constitute the core membrane fusion machinery of intracellular transport and intercellular communication. A little more than ten years ago, it was proposed that the long N-terminal domain of a subset of SNAREs, henceforth called the longin domain, could be a crucial regulator with multiple functions in membrane trafficking. Structural, biochemical and cell biology studies have now produced a large set of data that support this hypothesis and indicate a role for the longin domain in regulating the sorting and activity of SNAREs. Here, we review the first decade of structure-function data on the three prototypical longin SNAREs: Ykt6, VAMP7 and Sec22b. We will, in particular, highlight the conserved molecular mechanisms that allow longin domains to fold back onto the fusion-inducing SNARE coiled-coil domain, thereby inhibiting membrane fusion, and describe the interactions of longin SNAREs with proteins that regulate their intracellular sorting. This dual function of the longin domain in regulating both the membrane localization and membrane fusion activity of SNAREs points to its role as a key regulatory module of intracellular trafficking.
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Affiliation(s)
- Frédéric Daste
- Université Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, CNRS UMR 7592, Membrane Traffic in Health & Disease, INSERM ERL U950, Paris F-75013, France
| | - Thierry Galli
- Université Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, CNRS UMR 7592, Membrane Traffic in Health & Disease, INSERM ERL U950, Paris F-75013, France
| | - David Tareste
- Université Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, CNRS UMR 7592, Membrane Traffic in Health & Disease, INSERM ERL U950, Paris F-75013, France
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20
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Zhang B, Karnik R, Wang Y, Wallmeroth N, Blatt MR, Grefen C. The Arabidopsis R-SNARE VAMP721 Interacts with KAT1 and KC1 K+ Channels to Moderate K+ Current at the Plasma Membrane. THE PLANT CELL 2015; 27:1697-717. [PMID: 26002867 PMCID: PMC4498211 DOI: 10.1105/tpc.15.00305] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 04/08/2015] [Accepted: 05/06/2015] [Indexed: 05/04/2023]
Abstract
SNARE (soluble N-ethylmaleimide-sensitive factor protein attachment protein receptor) proteins drive vesicle traffic, delivering membrane and cargo to target sites within the cell and at its surface. They contribute to cell homeostasis, morphogenesis, and pathogen defense. A subset of SNAREs, including the Arabidopsis thaliana SNARE SYP121, are known also to coordinate solute uptake via physical interactions with K(+) channels and to moderate their gating at the plasma membrane. Here, we identify a second subset of SNAREs that interact to control these K(+) channels, but with opposing actions on gating. We show that VAMPs (vesicle-associated membrane proteins), which target vesicles to the plasma membrane, also interact with and suppress the activities of the inward-rectifying K(+) channels KAT1 and KC1. Interactions were evident in yeast split-ubiquitin assays, they were recovered in vivo by ratiometric bimolecular fluorescence complementation, and they were sensitive to mutation of a single residue, Tyr-57, within the longin domain of VAMP721. Interaction was also recovered on exchange of the residue at this site in the homolog VAMP723, which normally localizes to the endoplasmic reticulum and otherwise did not interact. Functional analysis showed reduced channel activity and alterations in voltage sensitivity that are best explained by a physical interaction with the channel gates. These actions complement those of SYP121, a cognate SNARE partner of VAMP721, and lead us to propose that the channel interactions reflect a "hand-off" in channel control between the two SNARE proteins that is woven together with vesicle fusion.
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Affiliation(s)
- Ben Zhang
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Rucha Karnik
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Yizhou Wang
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | | | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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De Franceschi N, Wild K, Schlacht A, Dacks JB, Sinning I, Filippini F. Longin and GAF domains: structural evolution and adaptation to the subcellular trafficking machinery. Traffic 2013; 15:104-21. [PMID: 24107188 DOI: 10.1111/tra.12124] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 09/18/2013] [Accepted: 09/23/2013] [Indexed: 11/28/2022]
Abstract
Endomembrane trafficking is one of the most prominent cytological features of eukaryotes. Given their widespread distribution and specialization, coiled-coil domains, coatomer domains, small GTPases and Longin domains are considered primordial 'building blocks' of the membrane trafficking machineries. Longin domains are conserved across eukaryotes and were likely to be present in the Last Eukaryotic Common Ancestor. The Longin fold is based on the α-β-α sandwich architecture and a unique topology, possibly accounting for the special adaptation to the eukaryotic trafficking machinery. The ancient Per ARNT Sim (PAS) and cGMP-specific phosphodiesterases, Adenylyl cyclases and FhlA (GAF) family domains show a similar architecture, and the identification of prokaryotic counterparts of GAF domains involved in trafficking provides an additional connection for the endomembrane system back into the pre-eukaryotic world. Proteome-wide, comparative bioinformatic analyses of the domains reveal three binding regions (A, B and C) mediating either specific or conserved protein-protein interactions. While the A region mediates intra- and inter-molecular interactions, the B region is involved in binding small GTPases, thus providing an evolutionary connection among major building blocks in the endomembrane system. Finally, we propose that the peculiar interaction surface of the C region of the Longin domain allowed it to extensively integrate into the endomembrane trafficking machinery in the earliest stages of building the eukaryotic cell.
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Affiliation(s)
- Nicola De Franceschi
- Molecular Biology and Bioinformatics Unit, Department of Biology, University of Padova, Padova, Italy; Current address: Centre for Biotechnology, University of Turku, Turku, Finland
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22
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Sahlender DA, Kozik P, Miller SE, Peden AA, Robinson MS. Uncoupling the functions of CALM in VAMP sorting and clathrin-coated pit formation. PLoS One 2013; 8:e64514. [PMID: 23741335 PMCID: PMC3669311 DOI: 10.1371/journal.pone.0064514] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/15/2013] [Indexed: 11/19/2022] Open
Abstract
CALM (clathrin assembly lymphoid myeloid leukemia protein) is a cargo-selective adaptor for the post-Golgi R-SNAREs VAMPs 2, 3, and 8, and it also regulates the size of clathrin-coated pits and vesicles at the plasma membrane. The present study has two objectives: to determine whether CALM can sort additional VAMPs, and to investigate whether VAMP sorting contributes to CALM-dependent vesicle size regulation. Using a flow cytometry-based endocytosis efficiency assay, we demonstrate that CALM is also able to sort VAMPs 4 and 7, even though they have sorting signals for other clathrin adaptors. CALM homologues are present in nearly every eukaryote, suggesting that the CALM family may have evolved as adaptors for retrieving all post-Golgi VAMPs from the plasma membrane. Using a knockdown/rescue system, we show that wild-type CALM restores normal VAMP sorting in CALM-depleted cells, but that two non-VAMP-binding mutants do not. However, when we assayed the effect of CALM depletion on coated pit morphology, using a fluorescence microscopy-based assay, we found that the two mutants were as effective as wild-type CALM. Thus, we can uncouple the sorting function of CALM from its structural role.
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Affiliation(s)
- Daniela A. Sahlender
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Patrycja Kozik
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Sharon E. Miller
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Andrew A. Peden
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Margaret S. Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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23
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Burgo A, Casano AM, Kuster A, Arold ST, Wang G, Nola S, Verraes A, Dingli F, Loew D, Galli T. Increased activity of the vesicular soluble N-ethylmaleimide-sensitive factor attachment protein receptor TI-VAMP/VAMP7 by tyrosine phosphorylation in the Longin domain. J Biol Chem 2013; 288:11960-72. [PMID: 23471971 DOI: 10.1074/jbc.m112.415075] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Vesicular (v)- and target (t)-SNAREs play essential roles in intracellular membrane fusion through the formation of cytoplasmic α-helical bundles. Several v-SNAREs have a Longin N-terminal extension that, by promoting a closed conformation, plays an autoinhibitory function and decreases SNARE complex formation and membrane fusion efficiency. The molecular mechanism leading to Longin v-SNARE activation is largely unknown. Here we find that exocytosis mediated by the Longin v-SNARE TI-VAMP/VAMP7 is activated by tonic treatment with insulin and insulin-like growth factor-1 but not by depolarization and intracellular calcium rise. In search of a potential downstream mechanism, we found that TI-VAMP is phosphorylated in vitro by c-Src kinase on tyrosine 45 of the Longin domain. Accordingly, a mutation of tyrosine 45 into glutamate, but not phenylalanine, activates both t-SNARE binding and exocytosis. Activation of TI-VAMP-mediated exocytosis thus relies on tyrosine phosphorylation.
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Affiliation(s)
- Andrea Burgo
- Institut Jacques Monod, UMR 7592, CNRS, Université Paris Diderot, Sorbonne Paris Cité, F-75013 Paris, France
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24
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Schäfer IB, Hesketh GG, Bright NA, Gray SR, Pryor PR, Evans PR, Luzio JP, Owen DJ. The binding of Varp to VAMP7 traps VAMP7 in a closed, fusogenically inactive conformation. Nat Struct Mol Biol 2012; 19:1300-9. [PMID: 23104059 PMCID: PMC3605791 DOI: 10.1038/nsmb.2414] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 09/18/2012] [Indexed: 11/29/2022]
Abstract
SNAREs provide energy and specificity to membrane fusion events. Fusogenic trans-SNARE complexes are assembled from glutamine-contributing SNAREs (Q-SNAREs) embedded in one membrane and an arginine-contributing SNARE (R-SNARE) embedded in the other. Regulation of membrane fusion events is crucial for intracellular trafficking. We identify the endosomal protein Varp as an R-SNARE-binding regulator of SNARE complex formation. Varp colocalizes with and binds to VAMP7, an R-SNARE that is involved in both endocytic and secretory pathways. We present the structure of the second ankyrin repeat domain of mammalian Varp in complex with the cytosolic portion of VAMP7. The VAMP7-SNARE motif is trapped between Varp and the VAMP7 longin domain, and hence Varp kinetically inhibits the ability of VAMP7 to form SNARE complexes. This inhibition will be increased when Varp can also bind to other proteins present on the same membrane as VAMP7, such as Rab32-GTP.
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Affiliation(s)
- Ingmar B Schäfer
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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25
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Rizo J, Südhof TC. The Membrane Fusion Enigma: SNAREs, Sec1/Munc18 Proteins, and Their Accomplices—Guilty as Charged? Annu Rev Cell Dev Biol 2012; 28:279-308. [DOI: 10.1146/annurev-cellbio-101011-155818] [Citation(s) in RCA: 318] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Josep Rizo
- Departments of Biophysics, Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390;
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, California 94305;
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26
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Kasai H, Takahashi N, Tokumaru H. Distinct Initial SNARE Configurations Underlying the Diversity of Exocytosis. Physiol Rev 2012; 92:1915-64. [DOI: 10.1152/physrev.00007.2012] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The dynamics of exocytosis are diverse and have been optimized for the functions of synapses and a wide variety of cell types. For example, the kinetics of exocytosis varies by more than five orders of magnitude between ultrafast exocytosis in synaptic vesicles and slow exocytosis in large dense-core vesicles. However, in all cases, exocytosis is mediated by the same fundamental mechanism, i.e., the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. It is often assumed that vesicles need to be docked at the plasma membrane and SNARE proteins must be preassembled before exocytosis is triggered. However, this model cannot account for the dynamics of exocytosis recently reported in synapses and other cells. For example, vesicles undergo exocytosis without prestimulus docking during tonic exocytosis of synaptic vesicles in the active zone. In addition, epithelial and hematopoietic cells utilize cAMP and kinases to trigger slow exocytosis of nondocked vesicles. In this review, we summarize the manner in which the diversity of exocytosis reflects the initial configurations of SNARE assembly, including trans-SNARE, binary-SNARE, unitary-SNARE, and cis-SNARE configurations. The initial SNARE configurations depend on the particular SNARE subtype (syntaxin, SNAP25, or VAMP), priming proteins (Munc18, Munc13, CAPS, complexin, or snapin), triggering proteins (synaptotagmins, Doc2, and various protein kinases), and the submembraneous cytomatrix, and they are the key to determining the kinetics of subsequent exocytosis. These distinct initial configurations will help us clarify the common SNARE assembly processes underlying exocytosis and membrane trafficking in eukaryotic cells.
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Affiliation(s)
- Haruo Kasai
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Noriko Takahashi
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
| | - Hiroshi Tokumaru
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; and Faculty of Pharmaceutical Sciences at Kagawa, Tokushima Bunri University, Kagawa, Japan
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27
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Kent HM, Evans PR, Schäfer IB, Gray SR, Sanderson CM, Luzio JP, Peden AA, Owen DJ. Structural basis of the intracellular sorting of the SNARE VAMP7 by the AP3 adaptor complex. Dev Cell 2012; 22:979-88. [PMID: 22521722 PMCID: PMC3549491 DOI: 10.1016/j.devcel.2012.01.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 12/14/2011] [Accepted: 01/26/2012] [Indexed: 11/15/2022]
Abstract
VAMP7 is involved in the fusion of late endocytic compartments with other membranes. One possible mechanism of VAMP7 delivery to these late compartments is via the AP3 trafficking adaptor. We show that the linker of the δ-adaptin subunit of AP3 binds the VAMP7 longin domain and determines the structure of their complex. Mutation of residues on both partners abolishes the interaction in vitro and in vivo. The binding of VAMP7 to δ-adaptin requires the VAMP7 SNARE motif to be engaged in SNARE complex formation and hence AP3 must transport VAMP7 when VAMP7 is part of a cis-SNARE complex. The absence of δ-adaptin causes destabilization of the AP3 complex in mouse mocha fibroblasts and mislocalization of VAMP7. The mislocalization can be rescued by transfection with wild-type δ-adaptin but not by δ-adaptin containing mutations that abolish VAMP7 binding, despite in all cases intact AP3 being present and LAMP1 trafficking being rescued.
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Affiliation(s)
- Helen M Kent
- Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK
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28
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Vacca M, Albania L, Della Ragione F, Carpi A, Rossi V, Strazzullo M, De Franceschi N, Rossetto O, Filippini F, D'Esposito M. Alternative splicing of the human gene SYBL1 modulates protein domain architecture of Longin VAMP7/TI-VAMP, showing both non-SNARE and synaptobrevin-like isoforms. BMC Mol Biol 2011; 12:26. [PMID: 21609427 PMCID: PMC3123573 DOI: 10.1186/1471-2199-12-26] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 05/24/2011] [Indexed: 11/15/2022] Open
Abstract
Background The control of intracellular vesicle trafficking is an ideal target to weigh the role of alternative splicing in shaping genomes to make cells. Alternative splicing has been reported for several Soluble N-ethylmaleimide-sensitive factor Attachment protein REceptors of the vesicle (v-SNAREs) or of the target membrane (t-SNARES), which are crucial to intracellular membrane fusion and protein and lipid traffic in Eukaryotes. However, splicing has not yet been investigated in Longins, i.e. the most widespread v-SNAREs. Longins are essential in Eukaryotes and prototyped by VAMP7, Sec22b and Ykt6, sharing a conserved N-terminal Longin domain which regulates membrane fusion and subcellular targeting. Human VAMP7/TI-VAMP, encoded by gene SYBL1, is involved in multiple cell pathways, including control of neurite outgrowth. Results Alternative splicing of SYBL1 by exon skipping events results in the production of a number of VAMP7 isoforms. In-frame or frameshift coding sequence modifications modulate domain architecture of VAMP7 isoforms, which can lack whole domains or domain fragments and show variant or extra domains. Intriguingly, two main types of VAMP7 isoforms either share the inhibitory Longin domain and lack the fusion-promoting SNARE motif, or vice versa. Expression analysis in different tissues and cell lines, quantitative real time RT-PCR and confocal microscopy analysis of fluorescent protein-tagged isoforms demonstrate that VAMP7 variants have different tissue specificities and subcellular localizations. Moreover, design and use of isoform-specific antibodies provided preliminary evidence for the existence of splice variants at the protein level. Conclusions Previous evidence on VAMP7 suggests inhibitory functions for the Longin domain and fusion/growth promoting activity for the Δ-longin molecule. Thus, non-SNARE isoforms with Longin domain and non-longin SNARE isoforms might have somehow opposite regulatory functions. When considering splice variants as "natural mutants", evidence on modulation of subcellular localization by variation in domain combination can shed further light on targeting determinants. Although further work will be needed to characterize identified variants, our data might open the route to unravel novel molecular partners and mechanisms, accounting for the multiplicity of functions carried out by the different members of the Longin proteins family.
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Affiliation(s)
- Marcella Vacca
- Institute of Genetics and Biophysics A.Buzzati Traverso Consiglio Nazionale delle Ricerche, via P. Castellino 111, 80131 Naples, Italy
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