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Lee C, Lepore D, Lee SH, Kim TG, Buwa N, Lee J, Munson M, Yoon TY. Exocyst stimulates multiple steps of exocytic SNARE complex assembly and vesicle fusion. Nat Struct Mol Biol 2024:10.1038/s41594-024-01388-2. [PMID: 39242980 DOI: 10.1038/s41594-024-01388-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 08/13/2024] [Indexed: 09/09/2024]
Abstract
Exocyst is a large multisubunit tethering complex essential for targeting and fusion of secretory vesicles in eukaryotic cells. Although the assembled exocyst complex has been proposed to tether vesicles to the plasma membrane and activate soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) for membrane fusion, the key biochemical steps that exocyst stimulates in SNARE-mediated fusion are undetermined. Here we use a combination of single-molecule and bulk fluorescence assays to investigate the roles of purified octameric yeast exocyst complexes in a reconstituted yeast exocytic SNARE assembly and vesicle fusion system. Exocyst had stimulatory roles in multiple distinct steps ranging from SNARE protein activation to binary and ternary complex assembly. Importantly, exocyst had a downstream role in driving membrane fusion and full content mixing of vesicle lumens. Our data suggest that exocyst provides extensive chaperoning functions across the entire process of SNARE complex assembly and fusion, thereby governing exocytosis at multiple steps.
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Affiliation(s)
- Chanwoo Lee
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Dante Lepore
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Seung-Hak Lee
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Tae Gyun Kim
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Natasha Buwa
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jongchan Lee
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Mary Munson
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA, USA.
| | - Tae-Young Yoon
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, South Korea.
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2
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Szabó L, Pollio AR, Vogel GF. Intracellular Trafficking Defects in Congenital Intestinal and Hepatic Diseases. Traffic 2024; 25:e12954. [PMID: 39187475 DOI: 10.1111/tra.12954] [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: 04/30/2024] [Revised: 06/11/2024] [Accepted: 07/30/2024] [Indexed: 08/28/2024]
Abstract
Enterocytes and liver cells fulfill important metabolic and barrier functions and are responsible for crucial vectorial secretive and absorptive processes. To date, genetic diseases affecting metabolic enzymes or transmembrane transporters in the intestine and the liver are better comprehended than mutations affecting intracellular trafficking. In this review, we explore the emerging knowledge on intracellular trafficking defects and their clinical manifestations in both the intestine and the liver. We provide a detailed overview including more investigated diseases such as the canonical, variant and associated forms of microvillus inclusion disease, as well as recently described pathologies, highlighting the complexity and disease relevance of several trafficking pathways. We give examples of how intracellular trafficking hubs, such as the apical recycling endosome system, the trans-Golgi network, lysosomes, or the Golgi-to-endoplasmic reticulum transport are involved in the pathomechanism and lead to disease. Ultimately, understanding these processes could spark novel therapeutic approaches, which would greatly improve the quality of life of the affected patients.
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Affiliation(s)
- Luca Szabó
- Institute of Cell Biology, Medical University of Innsbruck, Innsbruck, Austria
| | - Adam R Pollio
- Institute of Cell Biology, Medical University of Innsbruck, Innsbruck, Austria
| | - Georg Friedrich Vogel
- Institute of Cell Biology, Medical University of Innsbruck, Innsbruck, Austria
- Department of Paediatrics I, Medical University of Innsbruck, Innsbruck, Austria
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3
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Duan M, Plemel RL, Takenaka T, Lin A, Delgado BM, Nattermann U, Nickerson DP, Mima J, Miller EA, Merz AJ. SNARE chaperone Sly1 directly mediates close-range vesicle tethering. J Cell Biol 2024; 223:e202001032. [PMID: 38478018 PMCID: PMC10943277 DOI: 10.1083/jcb.202001032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 12/20/2023] [Accepted: 02/22/2024] [Indexed: 03/17/2024] Open
Abstract
The essential Golgi protein Sly1 is a member of the Sec1/mammalian Unc-18 (SM) family of SNARE chaperones. Sly1 was originally identified through remarkable gain-of-function alleles that bypass requirements for diverse vesicle tethering factors. Employing genetic analyses and chemically defined reconstitutions of ER-Golgi fusion, we discovered that a loop conserved among Sly1 family members is not only autoinhibitory but also acts as a positive effector. An amphipathic lipid packing sensor (ALPS)-like helix within the loop directly binds high-curvature membranes. Membrane binding is required for relief of Sly1 autoinhibition and also allows Sly1 to directly tether incoming vesicles to the Qa-SNARE on the target organelle. The SLY1-20 mutation bypasses requirements for diverse tethering factors but loses this ability if the tethering activity is impaired. We propose that long-range tethers, including Golgins and multisubunit tethering complexes, hand off vesicles to Sly1, which then tethers at close range to initiate trans-SNARE complex assembly and fusion in the early secretory pathway.
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Affiliation(s)
- Mengtong Duan
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Rachael L. Plemel
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | | | - Ariel Lin
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Department of Biology, California State University, San Bernardino, CA, USA
| | | | - Una Nattermann
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Biophysics, Structure, and Design Graduate Program, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | | | - Joji Mima
- Institute for Protein Research, Osaka University, Osaka, Japan
| | | | - Alexey J. Merz
- Department of Biochemistry, University of Washington, Seattle, WA, USA
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4
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DAmico KA, Stanton AE, Shirkey JD, Travis SM, Jeffrey PD, Hughson FM. Structure of a membrane tethering complex incorporating multiple SNAREs. Nat Struct Mol Biol 2024; 31:246-254. [PMID: 38196032 PMCID: PMC10923073 DOI: 10.1038/s41594-023-01164-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 10/26/2023] [Indexed: 01/11/2024]
Abstract
Most membrane fusion reactions in eukaryotic cells are mediated by multisubunit tethering complexes (MTCs) and SNARE proteins. MTCs are much larger than SNAREs and are thought to mediate the initial attachment of two membranes. Complementary SNAREs then form membrane-bridging complexes whose assembly draws the membranes together for fusion. Here we present a cryo-electron microscopy structure of the simplest known MTC, the 255-kDa Dsl1 complex of Saccharomyces cerevisiae, bound to the two SNAREs that anchor it to the endoplasmic reticulum. N-terminal domains of the SNAREs form an integral part of the structure, stabilizing a Dsl1 complex configuration with unexpected similarities to the 850-kDa exocyst MTC. The structure of the SNARE-anchored Dsl1 complex and its comparison with exocyst reveal what are likely to be common principles underlying MTC function. Our structure also implies that tethers and SNAREs can work together as a single integrated machine.
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Affiliation(s)
- Kevin A DAmico
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Abigail E Stanton
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Jaden D Shirkey
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Sophie M Travis
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Philip D Jeffrey
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
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5
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Ji Q, Zhang K, Cao N, You X, Cao S, Wang M, Guo J, Wang H, Mei K. Highly efficient overexpression and purification of multisubunit tethering complexes in Saccharomyces cerevisiae. Protein Expr Purif 2023; 212:106351. [PMID: 37574178 DOI: 10.1016/j.pep.2023.106351] [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: 05/05/2023] [Revised: 08/02/2023] [Accepted: 08/09/2023] [Indexed: 08/15/2023]
Abstract
Vesicle trafficking is a fundamental cellular process that ensures proper material exchange between organelles in eukaryotic cells, and multisubunit tethering complexes (MTCs) are essential in this process. The heterohexameric homotypic fusion and protein sorting (HOPS) complex, which functions in the endolysosomal pathway, is a member of MTCs. Despite its critical role, the complex composition and low-expression level of HOPS have made its expression and purification extremely challenging. In this study, we present a highly efficient strategy for overexpressing and purifying HOPS from Saccharomyces cerevisiae. We achieved HOPS overexpression by integrating a strong promoter TEF1 before each subunit using the gRNA-tRNA array for CRISPR-Cas9 (GTR-CRISPR) system. The HOPS complex was subsequently purified using Staphylococcus aureus protein A (ProtA) affinity purification and size-exclusion chromatography, resulting in high purity and homogeneity. We obtained two-fold more HOPS using this method than that obtained using the commonly used GAL1 promoter-controlled HOPS overexpression. Negative staining electron microscopy analysis confirmed the correct assembly of HOPS. Notably, we also successfully purified two other MTCs, class C core vacuole/endosome tethering (CORVET) and Golgi-associated retrograde protein (GARP) using this approach. Our findings facilitate further in vitro biochemical characterization and functional studies of MTCs and provide a useful guide for the preparation of other heterogenic multisubunit complexes.
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Affiliation(s)
- Qiushuang Ji
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
| | - Ke Zhang
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
| | - Na Cao
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Xiaoyu You
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
| | - Shuaihua Cao
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
| | - Mengya Wang
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
| | - Jiatian Guo
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
| | - Hongwei Wang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Kunrong Mei
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
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6
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Kiss RS, Chicoine J, Khalil Y, Sladek R, Chen H, Pisaturo A, Martin C, Dale JD, Brudenell TA, Kamath A, Kyei-Boahen J, Hafiane A, Daliah G, Alecki C, Hopes TS, Heier M, Aligianis IA, Lebrun JJ, Aspden J, Paci E, Kerksiek A, Lütjohann D, Clayton P, Wills JC, von Kriegsheim A, Nilsson T, Sheridan E, Handley MT. Comparative proximity biotinylation implicates the small GTPase RAB18 in sterol mobilization and biosynthesis. J Biol Chem 2023; 299:105295. [PMID: 37774976 PMCID: PMC10641524 DOI: 10.1016/j.jbc.2023.105295] [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: 03/16/2023] [Revised: 09/14/2023] [Accepted: 09/17/2023] [Indexed: 10/01/2023] Open
Abstract
Loss of functional RAB18 causes the autosomal recessive condition Warburg Micro syndrome. To better understand this disease, we used proximity biotinylation to generate an inventory of potential RAB18 effectors. A restricted set of 28 RAB18 interactions were dependent on the binary RAB3GAP1-RAB3GAP2 RAB18-guanine nucleotide exchange factor complex. Twelve of these 28 interactions are supported by prior reports, and we have directly validated novel interactions with SEC22A, TMCO4, and INPP5B. Consistent with a role for RAB18 in regulating membrane contact sites, interactors included groups of microtubule/membrane-remodeling proteins, membrane-tethering and docking proteins, and lipid-modifying/transporting proteins. Two of the putative interactors, EBP and OSBPL2/ORP2, have sterol substrates. EBP is a Δ8-Δ7 sterol isomerase, and ORP2 is a lipid transport protein. This prompted us to investigate a role for RAB18 in cholesterol biosynthesis. We found that the cholesterol precursor and EBP-product lathosterol accumulates in both RAB18-null HeLa cells and RAB3GAP1-null fibroblasts derived from an affected individual. Furthermore, de novo cholesterol biosynthesis is impaired in cells in which RAB18 is absent or dysregulated or in which ORP2 expression is disrupted. Our data demonstrate that guanine nucleotide exchange factor-dependent Rab interactions are highly amenable to interrogation by proximity biotinylation and may suggest that Micro syndrome is a cholesterol biosynthesis disorder.
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Affiliation(s)
- Robert S Kiss
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.
| | - Jarred Chicoine
- Metabolic Disorders and Complications (MEDIC) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Youssef Khalil
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Robert Sladek
- Metabolic Disorders and Complications (MEDIC) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - He Chen
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Alessandro Pisaturo
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Cyril Martin
- Cardiovascular Health Across the Lifespan (CHAL) Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Jessica D Dale
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom
| | - Tegan A Brudenell
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom
| | - Archith Kamath
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom; Division of Medical Sciences, University of Oxford, Oxford, United Kingdom
| | - Jeffrey Kyei-Boahen
- Department of Medicine, McGill University Health Centre, CHAL Research Program, Montreal, Canada
| | - Anouar Hafiane
- Department of Medicine, McGill University Health Centre, CHAL Research Program, Montreal, Canada
| | - Girija Daliah
- Department of Medicine, McGill University Health Centre, Cancer Research Program, Montreal, Canada
| | - Célia Alecki
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Tayah S Hopes
- Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Martin Heier
- Department of Clinical Neuroscience for Children, Oslo University Hospital, Oslo, Norway
| | - Irene A Aligianis
- Medical and Developmental Genetics, Medical Research Council Human Genetics Unit, Edinburgh, United Kingdom
| | - Jean-Jacques Lebrun
- Department of Medicine, McGill University Health Centre, Cancer Research Program, Montreal, Canada
| | - Julie Aspden
- Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Emanuele Paci
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Anja Kerksiek
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Dieter Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Peter Clayton
- Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Jimi C Wills
- Cancer Research United Kingdom Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom; Firefinch Software Ltd, Edinburgh, United Kingdom
| | - Alex von Kriegsheim
- Cancer Research United Kingdom Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
| | - Tommy Nilsson
- Cancer Research Program (CRP), Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Eamonn Sheridan
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom
| | - Mark T Handley
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom; Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.
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7
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Bravo-Plaza I, Tagua VG, Arst HN, Alonso A, Pinar M, Monterroso B, Galindo A, Peñalva MA. The Uso1 globular head interacts with SNAREs to maintain viability even in the absence of the coiled-coil domain. eLife 2023; 12:e85079. [PMID: 37249218 PMCID: PMC10275640 DOI: 10.7554/elife.85079] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/29/2023] [Indexed: 05/31/2023] Open
Abstract
Uso1/p115 and RAB1 tether ER-derived vesicles to the Golgi. Uso1/p115 contains a globular-head-domain (GHD), a coiled-coil (CC) mediating dimerization/tethering, and a C-terminal region (CTR) interacting with golgins. Uso1/p115 is recruited to vesicles by RAB1. Genetic studies placed Uso1 paradoxically acting upstream of, or in conjunction with RAB1 (Sapperstein et al., 1996). We selected two missense mutations in uso1 resulting in E6K and G540S in the GHD that rescued lethality of rab1-deficient Aspergillus nidulans. The mutations are phenotypically additive, their combination suppressing the complete absence of RAB1, which emphasizes the key physiological role of the GHD. In living hyphae Uso1 recurs on puncta (60 s half-life) colocalizing partially with the Golgi markers RAB1, Sed5, and GeaA/Gea1/Gea2, and totally with the retrograde cargo receptor Rer1, consistent with Uso1 dwelling in a very early Golgi compartment from which ER residents reaching the Golgi recycle back to the ER. Localization of Uso1, but not of Uso1E6K/G540S, to puncta is abolished by compromising RAB1 function, indicating that E6K/G540S creates interactions bypassing RAB1. That Uso1 delocalization correlates with a decrease in the number of Gea1 cisternae supports that Uso1-and-Rer1-containing puncta are where the protein exerts its physiological role. In S-tag-coprecipitation experiments, Uso1 is an associate of the Sed5/Bos1/Bet1/Sec22 SNARE complex zippering vesicles with the Golgi, with Uso1E6K/G540S showing a stronger association. Using purified proteins, we show that Bos1 and Bet1 bind the Uso1 GHD directly. However, Bet1 is a strong E6K/G540S-independent binder, whereas Bos1 is weaker but becomes as strong as Bet1 when the GHD carries E6K/G540S. G540S alone markedly increases GHD binding to Bos1, whereas E6K causes a weaker effect, correlating with their phenotypic contributions. AlphaFold2 predicts that G540S increases the binding of the GHD to the Bos1 Habc domain. In contrast, E6K lies in an N-terminal, potentially alpha-helical, region that sensitive genetic tests indicate as required for full Uso1 function. Remarkably, this region is at the end of the GHD basket opposite to the end predicted to interact with Bos1. We show that, unlike dimeric full-length and CTR∆ Uso1 proteins, the GHD lacking the CC/CTR dimerization domain, whether originating from bacteria or Aspergillus extracts and irrespective of whether it carries or not E6K/G540S, would appear to be monomeric. With the finding that overexpression of E6K/G540S and wild-type GHD complement uso1∆, our data indicate that the GHD monomer is capable of providing, at least partially, the essential Uso1 functions, and that long-range tethering activity is dispensable. Rather, these findings strongly suggest that the essential role of Uso1 involves the regulation of SNAREs.
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Affiliation(s)
- Ignacio Bravo-Plaza
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Victor G Tagua
- Instituto de Tecnologías Biomédicas, Hospital Universitario Nuestra Señora de CandelariaSanta Cruz de TenerifeSpain
| | - Herbert N Arst
- Department of Infectious Diseases, Faculty of Medicine, Flowers Building, Imperial CollegeLondonUnited Kingdom
| | - Ana Alonso
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Mario Pinar
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Begoña Monterroso
- Department of Structural and Chemical Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Antonio Galindo
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
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8
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Pazos I, Puig‐Tintó M, Betancur L, Cordero J, Jiménez‐Menéndez N, Abella M, Hernández AC, Duran AG, Adachi‐Fernández E, Belmonte‐Mateos C, Sabido‐Bozo S, Tosi S, Nezu A, Oliva B, Colombelli J, Graham TR, Yoshimori T, Muñiz M, Hamasaki M, Gallego O. The P4-ATPase Drs2 interacts with and stabilizes the multisubunit tethering complex TRAPPIII in yeast. EMBO Rep 2023; 24:e56134. [PMID: 36929574 PMCID: PMC10157312 DOI: 10.15252/embr.202256134] [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: 09/16/2022] [Revised: 02/10/2023] [Accepted: 02/17/2023] [Indexed: 03/17/2023] Open
Abstract
Multisubunit Tethering Complexes (MTCs) are a set of conserved protein complexes that tether vesicles at the acceptor membrane. Interactions with other components of the trafficking machinery regulate MTCs through mechanisms that are partially understood. Here, we systematically investigate the interactome that regulates MTCs. We report that P4-ATPases, a family of lipid flippases, interact with MTCs that participate in the anterograde and retrograde transport at the Golgi, such as TRAPPIII. We use the P4-ATPase Drs2 as a paradigm to investigate the mechanism and biological relevance of this interplay during transport of Atg9 vesicles. Binding of Trs85, the sole-specific subunit of TRAPPIII, to the N-terminal tail of Drs2 stabilizes TRAPPIII on membranes loaded with Atg9 and is required for Atg9 delivery during selective autophagy, a role that is independent of P4-ATPase canonical functions. This mechanism requires a conserved I(S/R)TTK motif that also mediates the interaction of the P4-ATPases Dnf1 and Dnf2 with MTCs, suggesting a broader role of P4-ATPases in MTC regulation.
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Affiliation(s)
- Irene Pazos
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Marta Puig‐Tintó
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Laura Betancur
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Jorge Cordero
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | | | - Marc Abella
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Altair C Hernández
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Ana G Duran
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Emi Adachi‐Fernández
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Carla Belmonte‐Mateos
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
| | - Susana Sabido‐Bozo
- Department of Cell BiologyUniversity of SevilleSevilleSpain
- Instituto de Biomedicina de Sevilla (IBiS)Hospital Universitario Virgen del Rocío/CSIC/Universidad de SevillaSevilleSpain
| | - Sébastien Tosi
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
| | - Akiko Nezu
- Department of Genetics, Graduate School of MedicineOsaka UniversityOsakaJapan
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Baldomero Oliva
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
- Structural Bioinformatics Lab (GRIB‐IMIM)BarcelonaSpain
| | - Julien Colombelli
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
| | - Todd R Graham
- Department of Biological SciencesVanderbilt UniversityNashvilleTNUSA
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of MedicineOsaka UniversityOsakaJapan
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Manuel Muñiz
- Department of Cell BiologyUniversity of SevilleSevilleSpain
- Instituto de Biomedicina de Sevilla (IBiS)Hospital Universitario Virgen del Rocío/CSIC/Universidad de SevillaSevilleSpain
| | - Maho Hamasaki
- Department of Genetics, Graduate School of MedicineOsaka UniversityOsakaJapan
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Oriol Gallego
- Department of Medicine and Life Sciences (MELIS)Pompeu Fabra University (UPF)BarcelonaSpain
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9
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Taylor RJ, Tagiltsev G, Briggs JAG. The structure of COPI vesicles and regulation of vesicle turnover. FEBS Lett 2023; 597:819-835. [PMID: 36513395 DOI: 10.1002/1873-3468.14560] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/15/2022]
Abstract
COPI-coated vesicles mediate transport between Golgi stacks and retrograde transport from the Golgi to the endoplasmic reticulum. The COPI coat exists as a stable heptameric complex in the cytosol termed coatomer and is recruited en bloc to the membrane for vesicle formation. Recruitment of COPI onto membranes is mediated by the Arf family of small GTPases, which, in their GTP-bound state, bind both membrane and coatomer. Arf GTPases also influence cargo selection, vesicle scission and vesicle uncoating. Guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) regulate nucleotide binding by Arf GTPases. To understand the mechanism of COPI-coated vesicle trafficking, it is necessary to characterize the interplay between coatomer and Arf GTPases and their effectors. It is also necessary to understand interactions between coatomer and cargo, cargo adaptors/receptors and tethers facilitating binding to the target membrane. Here, we summarize current knowledge of COPI coat protein structure; we describe how structural and biochemical studies contributed to this knowledge; we review mechanistic insights into COPI vesicle biogenesis and disassembly; and we discuss the potential to answer open questions in the field.
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Affiliation(s)
- Rebecca J Taylor
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Grigory Tagiltsev
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - John A G Briggs
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Martinsried, Germany
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10
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DAmico KA, Stanton AE, Shirkey JD, Travis SM, Jeffrey PD, Hughson FM. Structure of a Membrane Tethering Complex Incorporating Multiple SNAREs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526244. [PMID: 36778436 PMCID: PMC9915479 DOI: 10.1101/2023.01.30.526244] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Most membrane fusion reactions in eukaryotic cells are mediated by membrane tethering complexes (MTCs) and SNARE proteins. MTCs are much larger than SNAREs and are thought to mediate the initial attachment of two membranes. Complementary SNAREs then form membrane-bridging complexes whose assembly draws the membranes together for fusion. Here, we present a cryo-EM structure of the simplest known MTC, the 255-kDa Dsl1 complex, bound to the two SNAREs that anchor it to the endoplasmic reticulum. N-terminal domains of the SNAREs form an integral part of the structure, stabilizing a Dsl1 complex configuration with remarkable and unexpected similarities to the 850-kDa exocyst MTC. The structure of the SNARE-anchored Dsl1 complex and its comparison with exocyst reveal what are likely to be common principles underlying MTC function. Our structure also implies that tethers and SNAREs can work together as a single integrated machine.
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Affiliation(s)
- Kevin A DAmico
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Abigail E Stanton
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Jaden D Shirkey
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Sophie M Travis
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Philip D Jeffrey
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
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11
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Cui L, Li H, Xi Y, Hu Q, Liu H, Fan J, Xiang Y, Zhang X, Shui W, Lai Y. Vesicle trafficking and vesicle fusion: mechanisms, biological functions, and their implications for potential disease therapy. MOLECULAR BIOMEDICINE 2022; 3:29. [PMID: 36129576 PMCID: PMC9492833 DOI: 10.1186/s43556-022-00090-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/12/2022] [Indexed: 11/10/2022] Open
Abstract
Intracellular vesicle trafficking is the fundamental process to maintain the homeostasis of membrane-enclosed organelles in eukaryotic cells. These organelles transport cargo from the donor membrane to the target membrane through the cargo containing vesicles. Vesicle trafficking pathway includes vesicle formation from the donor membrane, vesicle transport, and vesicle fusion with the target membrane. Coat protein mediated vesicle formation is a delicate membrane budding process for cargo molecules selection and package into vesicle carriers. Vesicle transport is a dynamic and specific process for the cargo containing vesicles translocation from the donor membrane to the target membrane. This process requires a group of conserved proteins such as Rab GTPases, motor adaptors, and motor proteins to ensure vesicle transport along cytoskeletal track. Soluble N-ethyl-maleimide-sensitive factor (NSF) attachment protein receptors (SNARE)-mediated vesicle fusion is the final process for vesicle unloading the cargo molecules at the target membrane. To ensure vesicle fusion occurring at a defined position and time pattern in eukaryotic cell, multiple fusogenic proteins, such as synaptotagmin (Syt), complexin (Cpx), Munc13, Munc18 and other tethering factors, cooperate together to precisely regulate the process of vesicle fusion. Dysfunctions of the fusogenic proteins in SNARE-mediated vesicle fusion are closely related to many diseases. Recent studies have suggested that stimulated membrane fusion can be manipulated pharmacologically via disruption the interface between the SNARE complex and Ca2+ sensor protein. Here, we summarize recent insights into the molecular mechanisms of vesicle trafficking, and implications for the development of new therapeutics based on the manipulation of vesicle fusion.
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12
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Wang S, Ma C. Neuronal SNARE complex assembly guided by Munc18-1 and Munc13-1. FEBS Open Bio 2022; 12:1939-1957. [PMID: 35278279 PMCID: PMC9623535 DOI: 10.1002/2211-5463.13394] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/28/2022] [Accepted: 03/10/2022] [Indexed: 01/25/2023] Open
Abstract
Neurotransmitter release by Ca2+ -triggered synaptic vesicle exocytosis is essential for information transmission in the nervous system. The soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs) syntaxin-1, SNAP-25, and synaptobrevin-2 form the SNARE complex to bring synaptic vesicles and the plasma membranes together and to catalyze membrane fusion. Munc18-1 and Munc13-1 regulate synaptic vesicle priming via orchestrating neuronal SNARE complex assembly. In this review, we summarize recent advances toward the functions and molecular mechanisms of Munc18-1 and Munc13-1 in guiding neuronal SNARE complex assembly, and discuss the functional similarities and differences between Munc18-1 and Munc13-1 in neurons and their homologs in other intracellular membrane trafficking systems.
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Affiliation(s)
- Shen Wang
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
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13
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Ma X, Zhao X, Zhang H, Zhang Y, Sun S, Li Y, Long Z, Liu Y, Zhang X, Li R, Tan L, Jiang L, Zhu JK, Li L. MAG2 and MAL Regulate Vesicle Trafficking and Auxin Homeostasis With Functional Redundancy. FRONTIERS IN PLANT SCIENCE 2022; 13:849532. [PMID: 35371137 PMCID: PMC8966843 DOI: 10.3389/fpls.2022.849532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Auxin is a central phytohormone and controls almost all aspects of plant development and stress response. Auxin homeostasis is coordinately regulated by biosynthesis, catabolism, transport, conjugation, and deposition. Endoplasmic reticulum (ER)-localized MAIGO2 (MAG2) complex mediates tethering of arriving vesicles to the ER membrane, and it is crucial for ER export trafficking. Despite important regulatory roles of MAG2 in vesicle trafficking, the mag2 mutant had mild developmental abnormalities. MAG2 has one homolog protein, MAG2-Like (MAL), and the mal-1 mutant also had slight developmental phenotypes. In order to investigate MAG2 and MAL regulatory function in plant development, we generated the mag2-1 mal-1 double mutant. As expected, the double mutant exhibited serious developmental defects and more alteration in stress response compared with single mutants and wild type. Proteomic analysis revealed that signaling, metabolism, and stress response in mag2-1 mal-1 were affected, especially membrane trafficking and auxin biosynthesis, signaling, and transport. Biochemical and cell biological analysis indicated that the mag2-1 mal-1 double mutant had more serious defects in vesicle transport than the mag2-1 and mal-1 single mutants. The auxin distribution and abundance of auxin transporters were altered significantly in the mag2-1 and mal-1 single mutants and mag2-1 mal-1 double mutant. Our findings suggest that MAG2 and MAL regulate plant development and auxin homeostasis by controlling membrane trafficking, with functional redundancy.
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Affiliation(s)
- Xiaohui Ma
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaonan Zhao
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Hailong Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Yiming Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Shanwen Sun
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Ying Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Zhengbiao Long
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Yuqi Liu
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaomeng Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Rongxia Li
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixi Jiang
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixin Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
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14
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An SJ, Rivera-Molina F, Anneken A, Xi Z, McNellis B, Polejaev VI, Toomre D. An active tethering mechanism controls the fate of vesicles. Nat Commun 2021; 12:5434. [PMID: 34521845 PMCID: PMC8440521 DOI: 10.1038/s41467-021-25465-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/05/2021] [Indexed: 11/09/2022] Open
Abstract
Vesicle tethers are thought to underpin the efficiency of intracellular fusion by bridging vesicles to their target membranes. However, the interplay between tethering and fusion has remained enigmatic. Here, through optogenetic control of either a natural tether-the exocyst complex-or an artificial tether, we report that tethering regulates the mode of fusion. We find that vesicles mainly undergo kiss-and-run instead of full fusion in the absence of functional exocyst. Full fusion is rescued by optogenetically restoring exocyst function, in a manner likely dependent on the stoichiometry of tether engagement with the plasma membrane. In contrast, a passive artificial tether produces mostly kissing events, suggesting that kiss-and-run is the default mode of vesicle fusion. Optogenetic control of tethering further shows that fusion mode has physiological relevance since only full fusion could trigger lamellipodial expansion. These findings demonstrate that active coupling between tethering and fusion is critical for robust membrane merger.
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Affiliation(s)
- Seong J An
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Alexander Anneken
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Zhiqun Xi
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Brian McNellis
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Vladimir I Polejaev
- International Science and Technology Center, Yale University School of Medicine, New Haven, CT, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
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15
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Santana-Molina C, Gutierrez F, Devos DP. Homology and Modular Evolution of CATCHR at the Origin of the Eukaryotic Endomembrane System. Genome Biol Evol 2021; 13:6290715. [PMID: 34061181 PMCID: PMC8290106 DOI: 10.1093/gbe/evab125] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2021] [Indexed: 01/02/2023] Open
Abstract
The membrane trafficking is an essential process of eukaryotic cells, as it manages vesicular trafficking toward different parts of the cell. In this process, membrane fusions between vesicles and target membranes are mediated by several factors, including the multisubunit tethering complexes. One type of multisubunit tethering complex, the complexes associated with tethering containing helical rods (CATCHR), encompasses the exocyst, COG, GARP, and DSL1 complexes. The CATCHR share similarities at sequence, structural, and protein-complex organization level although their actual relationship is still poorly understood. In this study, we have re-evaluated CATCHR at different levels, demonstrating that gene duplications followed by neofunctionalization, were key for their origin. Our results, reveals that there are specific homology relationships and parallelism within and between the CATCHR suggesting that most of these complexes are composed by modular tetramers of four different kinds of proteins, three of them having a clear common origin. The extension of CATCHR family occurred concomitantly with the protein family expansions of their molecular partners, such as small GTPases and SNAREs, among others, and likely providing functional specificity. Our results provide novel insights into the structural organization and mechanism of action of CATCHR, with implications for the evolution of the endomembrane system of eukaryotes and promoting CATCHR as ideal candidates to study the evolution of multiprotein complexes.
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Affiliation(s)
- Carlos Santana-Molina
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide/Junta de Andalucía, Seville, Spain
| | - Fernando Gutierrez
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide/Junta de Andalucía, Seville, Spain.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Damien P Devos
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas/Universidad Pablo de Olavide/Junta de Andalucía, Seville, Spain
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16
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Morelli E, Speranza EA, Pellegrino E, Beznoussenko GV, Carminati F, Garré M, Mironov AA, Onorati M, Vaccari T. Activity of the SNARE Protein SNAP29 at the Endoplasmic Reticulum and Golgi Apparatus. Front Cell Dev Biol 2021; 9:637565. [PMID: 33718375 PMCID: PMC7945952 DOI: 10.3389/fcell.2021.637565] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/14/2021] [Indexed: 01/21/2023] Open
Abstract
Snap29 is a conserved regulator of membrane fusion essential to complete autophagy and to support other cellular processes, including cell division. In humans, inactivating SNAP29 mutations causes CEDNIK syndrome, a rare multi-systemic disorder characterized by congenital neuro-cutaneous alterations. The fibroblasts of CEDNIK patients show alterations of the Golgi apparatus (GA). However, whether and how Snap29 acts at the GA is unclear. Here we investigate SNAP29 function at the GA and endoplasmic reticulum (ER). As part of the elongated structures in proximity to these membrane compartments, a pool of SNAP29 forms a complex with Syntaxin18, or with Syntaxin5, which we find is required to engage SEC22B-loaded vesicles. Consistent with this, in HeLa cells, in neuroepithelial stem cells, and in vivo, decreased SNAP29 activity alters GA architecture and reduces ER to GA trafficking. Our data reveal a new regulatory function of Snap29 in promoting secretory trafficking.
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Affiliation(s)
- Elena Morelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Elisa A Speranza
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Enrica Pellegrino
- Dipartimento di Biologia, Unità di Biologia Cellulare e dello Sviluppo, Università di Pisa, Pisa, Italy
| | | | | | | | | | - Marco Onorati
- Dipartimento di Biologia, Unità di Biologia Cellulare e dello Sviluppo, Università di Pisa, Pisa, Italy
| | - Thomas Vaccari
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
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17
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Abstract
The functions of coat protein complex II (COPII) coats in cargo packaging and the creation of vesicles at the endoplasmic reticulum are conserved in eukaryotic protein secretion. Standard COPII vesicles, however, cannot handle the secretion of metazoan-specific cargoes such as procollagens, apolipoproteins, and mucins. Metazoans have thus evolved modules centered on proteins like TANGO1 (transport and Golgi organization 1) to engage COPII coats and early secretory pathway membranes to engineer a novel mode of cargo export at the endoplasmic reticulum.
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Affiliation(s)
- I Raote
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain; ,
| | - V Malhotra
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain; , .,Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain
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18
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Schoppe J, Mari M, Yavavli E, Auffarth K, Cabrera M, Walter S, Fröhlich F, Ungermann C. AP-3 vesicle uncoating occurs after HOPS-dependent vacuole tethering. EMBO J 2020; 39:e105117. [PMID: 32840906 PMCID: PMC7560216 DOI: 10.15252/embj.2020105117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 11/09/2022] Open
Abstract
Heterotetrameric adapter (AP) complexes cooperate with the small GTPase Arf1 or lipids in cargo selection, vesicle formation, and budding at endomembranes in eukaryotic cells. While most AP complexes also require clathrin as the outer vesicle shell, formation of AP-3-coated vesicles involved in Golgi-to-vacuole transport in yeast has been postulated to depend on Vps41, a subunit of the vacuolar HOPS tethering complex. HOPS has also been identified as the tether of AP-3 vesicles on vacuoles. To unravel this conundrum of a dual Vps41 function, we anchored Vps41 stably to the mitochondrial outer membrane. By monitoring AP-3 recruitment, we now show that Vps41 can tether AP-3 vesicles to mitochondria, yet AP-3 vesicles can form in the absence of Vps41 or clathrin. By proximity labeling and mass spectrometry, we identify the Arf1 GTPase-activating protein (GAP) Age2 at the AP-3 coat and show that tethering, but not fusion at the vacuole can occur without complete uncoating. We conclude that AP-3 vesicles retain their coat after budding and that their complete uncoating occurs only after tethering at the vacuole.
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Affiliation(s)
- Jannis Schoppe
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Erdal Yavavli
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Kathrin Auffarth
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Margarita Cabrera
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Farba, Barcelona, Spain
| | - Stefan Walter
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Department of Biology/Chemistry, Molecular Membrane Biology Section, University of Osnabrück, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
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19
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Gao J, Kurre R, Rose J, Walter S, Fröhlich F, Piehler J, Reggiori F, Ungermann C. Function of the SNARE Ykt6 on autophagosomes requires the Dsl1 complex and the Atg1 kinase complex. EMBO Rep 2020; 21:e50733. [PMID: 33025734 PMCID: PMC7726795 DOI: 10.15252/embr.202050733] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 12/11/2022] Open
Abstract
The mechanism and regulation of fusion between autophagosomes and lysosomes/vacuoles are still only partially understood in both yeast and mammals. In yeast, this fusion step requires SNARE proteins, the homotypic vacuole fusion and protein sorting (HOPS) tethering complex, the RAB7 GTPase Ypt7, and its guanine nucleotide exchange factor (GEF) Mon1‐Ccz1. We and others recently identified Ykt6 as the autophagosomal SNARE protein. However, it has not been resolved when and how lipid‐anchored Ykt6 is recruited onto autophagosomes. Here, we show that Ykt6 is recruited at an early stage of the formation of these carriers through a mechanism that depends on endoplasmic reticulum (ER)‐resident Dsl1 complex and COPII‐coated vesicles. Importantly, Ykt6 activity on autophagosomes is regulated by the Atg1 kinase complex, which inhibits Ykt6 through direct phosphorylation. Thus, our findings indicate that the Ykt6 pool on autophagosomal membranes is kept inactive by Atg1 phosphorylation, and once an autophagosome is ready to fuse with vacuole, Ykt6 dephosphorylation allows its engagement in the fusion event.
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Affiliation(s)
- Jieqiong Gao
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Rainer Kurre
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany
| | - Jaqueline Rose
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
| | - Jacob Piehler
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany.,Department of Biology/Chemistry, Biophysics Section, University of Osnabrück, Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
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20
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Chung CG, Park SS, Park JH, Lee SB. Dysregulated Plasma Membrane Turnover Underlying Dendritic Pathology in Neurodegenerative Diseases. Front Cell Neurosci 2020; 14:556461. [PMID: 33192307 PMCID: PMC7580253 DOI: 10.3389/fncel.2020.556461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/03/2020] [Indexed: 12/29/2022] Open
Abstract
Due to their enormous surface area compared to other cell types, neurons face unique challenges in properly handling supply and retrieval of the plasma membrane (PM)-a process termed PM turnover-in their distal areas. Because of the length and extensiveness of dendritic branches in neurons, the transport of materials needed for PM turnover from soma to distal dendrites will be inefficient and quite burdensome for somatic organelles. To meet local demands, PM turnover in dendrites most likely requires local cellular machinery, such as dendritic endocytic and secretory systems, dysregulation of which may result in dendritic pathology observed in various neurodegenerative diseases (NDs). Supporting this notion, a growing body of literature provides evidence to suggest the pathogenic contribution of dysregulated PM turnover to dendritic pathology in certain NDs. In this article, we present our perspective view that impaired dendritic endocytic and secretory systems may contribute to dendritic pathology by encumbering PM turnover in NDs.
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Affiliation(s)
- Chang Geon Chung
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Sung Soon Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Jeong Hyang Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Sung Bae Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
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21
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Ueda S, Tamura N, Mima J. Membrane Tethering Potency of Rab-Family Small GTPases Is Defined by the C-Terminal Hypervariable Regions. Front Cell Dev Biol 2020; 8:577342. [PMID: 33102484 PMCID: PMC7554592 DOI: 10.3389/fcell.2020.577342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022] Open
Abstract
Membrane tethering is a crucial step to determine the spatiotemporal specificity of secretory and endocytic trafficking pathways in all eukaryotic endomembrane systems. Recent biochemical studies by a chemically-defined reconstitution approach reveal that, in addition to the structurally-diverse classic tethering factors such as coiled-coil tethering proteins and multisubunit tethering complexes, Rab-family small GTPases also retain the inherent membrane tethering functions to directly and physically bridge two distinct lipid bilayers by themselves. Although Rab-mediated membrane tethering reactions are fairly efficient and specific in the physiological context, its mechanistic basis is yet to be understood. Here, to explore whether and how the intrinsic tethering potency of Rab GTPases is controlled by their C-terminal hypervariable region (HVR) domains that link the conserved small GTPase domains (G-domains) to membrane anchors at the C-terminus, we quantitatively compared tethering activities of two representative Rab isoforms in humans (Rab5a, Rab4a) and their HVR-deleted mutant forms. Strikingly, deletion of the HVR linker domains enabled both Rab5a and Rab4a isoforms to enhance their intrinsic tethering potency, exhibiting 5- to 50-fold higher initial velocities of tethering for the HVR-deleted mutants than those for the full-length, wild-type Rabs. Furthermore, we revealed that the tethering activity of full-length Rab5a was significantly reduced by the omission of anionic lipids and cholesterol from membrane lipids and, however, membrane tethering driven by HVR-deleted Rab5a mutant was completely insensitive to the headgroup composition of lipids. Reconstituted membrane tethering assays with the C-terminally-truncated mutants of Rab4a further uncovered that the N-terminal residues in the HVR linker, located adjacent to the G-domain, are critical for regulating the intrinsic tethering activity. In conclusion, our current findings establish that the non-conserved, flexible C-terminal HVR linker domains define membrane tethering potency of Rab-family small GTPases through controlling the close attachment of the globular G-domains to membrane surfaces, which confers the active tethering-competent state of the G-domains on lipid bilayers.
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Affiliation(s)
- Sanae Ueda
- Institute for Protein Research, Osaka University, Suita, Japan
| | - Naoki Tamura
- Institute for Protein Research, Osaka University, Suita, Japan
| | - Joji Mima
- Institute for Protein Research, Osaka University, Suita, Japan
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22
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Zhang Y, Yang J. Securing SNAREs for assembly. J Biol Chem 2020; 295:10136-10137. [PMID: 32709759 DOI: 10.1074/jbc.h120.014815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Indexed: 11/06/2022] Open
Abstract
SNARE proteins are essential for exocytosis, mediating the fusion of vesicles with their target membrane. Tethering factors play a key role in chaperoning SNARE assembly; however, the underlying molecular mechanisms are not well-understood. Here, Travis et al. report two crystal structures of a yeast tethering factor, the Dsl1 complex, bound with two SNARE proteins, revealing new insights into how tethering factors bridge vesicles to target membranes, recruit multiple SNARE proteins, trigger their conformational changes, and facilitate SNARE assembly.
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Affiliation(s)
- Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jie Yang
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
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23
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SNAREs, tethers and SM proteins: how to overcome the final barriers to membrane fusion? Biochem J 2020; 477:243-258. [PMID: 31951000 DOI: 10.1042/bcj20190050] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/04/2019] [Accepted: 12/16/2019] [Indexed: 12/18/2022]
Abstract
Physiological membrane vesicles are built to separate reaction spaces in a stable manner, even when they accidentally collide or are kept in apposition by spatial constraints in the cell. This requires a natural resistance to fusion and mixing of their content, which originates from substantial energetic barriers to membrane fusion [1]. To facilitate intracellular membrane fusion reactions in a controlled manner, proteinaceous fusion machineries have evolved. An important open question is whether protein fusion machineries actively pull the fusion reaction over the present free energy barriers, or whether they rather catalyze fusion by lowering those barriers. At first sight, fusion proteins such as SNARE complexes and viral fusion proteins appear to act as nano-machines, which mechanically transduce force to the membranes and thereby overcome the free energy barriers [2,3]. Whether fusion proteins additionally alter the free energy landscape of the fusion reaction via catalytic roles is less obvious. This is a question that we shall discuss in this review, with particular focus on the influence of the eukaryotic SNARE-dependent fusion machinery on the final step of the reaction, the formation and expansion of the fusion pore.
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24
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Kumar M, Gouw M, Michael S, Sámano-Sánchez H, Pancsa R, Glavina J, Diakogianni A, Valverde JA, Bukirova D, Čalyševa J, Palopoli N, Davey NE, Chemes LB, Gibson TJ. ELM-the eukaryotic linear motif resource in 2020. Nucleic Acids Res 2020; 48:D296-D306. [PMID: 31680160 PMCID: PMC7145657 DOI: 10.1093/nar/gkz1030] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/18/2019] [Accepted: 10/23/2019] [Indexed: 12/20/2022] Open
Abstract
The eukaryotic linear motif (ELM) resource is a repository of manually curated experimentally validated short linear motifs (SLiMs). Since the initial release almost 20 years ago, ELM has become an indispensable resource for the molecular biology community for investigating functional regions in many proteins. In this update, we have added 21 novel motif classes, made major revisions to 12 motif classes and added >400 new instances mostly focused on DNA damage, the cytoskeleton, SH2-binding phosphotyrosine motifs and motif mimicry by pathogenic bacterial effector proteins. The current release of the ELM database contains 289 motif classes and 3523 individual protein motif instances manually curated from 3467 scientific publications. ELM is available at: http://elm.eu.org.
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Affiliation(s)
- Manjeet Kumar
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Marc Gouw
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Sushama Michael
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Hugo Sámano-Sánchez
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.,Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Rita Pancsa
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary
| | - Juliana Glavina
- Instituto de Investigaciones Biotecnológicas (IIBio) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de San Martín. Av. 25 de Mayo y Francia, CP1650, Buenos Aires, Argentina
| | - Athina Diakogianni
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Jesús Alvarado Valverde
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Dayana Bukirova
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.,Nazarbayev University, Nur-Sultan 010000, Kazakhstan
| | - Jelena Čalyševa
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.,Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Nicolas Palopoli
- Department of Science and Technology, Universidad Nacional de Quilmes - CONICET, Bernal B1876BXD, Buenos Aires, Argentina
| | - Norman E Davey
- The Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Rd, Chelsea, London SW3 6JB, UK
| | - Lucía B Chemes
- Instituto de Investigaciones Biotecnológicas (IIBio) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de San Martín. Av. 25 de Mayo y Francia, CP1650, Buenos Aires, Argentina
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
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25
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Travis SM, DAmico K, Yu IM, McMahon C, Hamid S, Ramirez-Arellano G, Jeffrey PD, Hughson FM. Structural basis for the binding of SNAREs to the multisubunit tethering complex Dsl1. J Biol Chem 2020; 295:10125-10135. [PMID: 32409579 DOI: 10.1074/jbc.ra120.013654] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/01/2020] [Indexed: 01/02/2023] Open
Abstract
Multisubunit-tethering complexes (MTCs) are large (250 to >750 kDa), conserved macromolecular machines that are essential for soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated membrane fusion in all eukaryotes. MTCs are thought to organize membrane trafficking by mediating the initial long-range interaction between a vesicle and its target membrane and promoting the formation of membrane-bridging SNARE complexes. Previously, we reported the structure of the yeast Dsl1 complex, the simplest known MTC, which is essential for coat protein I (COPI) mediated transport from the Golgi to the endoplasmic reticulum (ER). This structure suggests how the Dsl1 complex might tether a vesicle to its target membrane by binding at one end to the COPI coat and at the other to ER-associated SNAREs. Here, we used X-ray crystallography to investigate these Dsl1-SNARE interactions in greater detail. The Dsl1 complex comprises three subunits that together form a two-legged structure with a central hinge. We found that distal regions of each leg bind N-terminal Habc domains of the ER SNAREs Sec20 (a Qb-SNARE) and Use1 (a Qc-SNARE). The observed binding modes appear to anchor the Dsl1 complex to the ER target membrane while simultaneously ensuring that both SNAREs are in open conformations, with their SNARE motifs available for assembly. The proximity of the two SNARE motifs, and therefore their ability to enter the same SNARE complex, will depend on the relative orientation of the two Dsl1 legs. These results underscore the critical roles of SNARE N-terminal domains in mediating interactions with other elements of the vesicle docking and fusion machinery.
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Affiliation(s)
- Sophie M Travis
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Kevin DAmico
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - I-Mei Yu
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Conor McMahon
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Safraz Hamid
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | | | - Philip D Jeffrey
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Frederick M Hughson
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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26
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Ganesan SJ, Feyder MJ, Chemmama IE, Fang F, Rout MP, Chait BT, Shi Y, Munson M, Sali A. Integrative structure and function of the yeast exocyst complex. Protein Sci 2020; 29:1486-1501. [PMID: 32239688 DOI: 10.1002/pro.3863] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022]
Abstract
Exocyst is an evolutionarily conserved hetero-octameric tethering complex that plays a variety of roles in membrane trafficking, including exocytosis, endocytosis, autophagy, cell polarization, cytokinesis, pathogen invasion, and metastasis. Exocyst serves as a platform for interactions between the Rab, Rho, and Ral small GTPases, SNARE proteins, and Sec1/Munc18 regulators that coordinate spatial and temporal fidelity of membrane fusion. However, its mechanism is poorly described at the molecular level. Here, we determine the molecular architecture of the yeast exocyst complex by an integrative approach, based on a 3D density map from negative-stain electron microscopy (EM) at ~16 Å resolution, 434 disuccinimidyl suberate and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride cross-links from chemical-crosslinking mass spectrometry, and partial atomic models of the eight subunits. The integrative structure is validated by a previously determined cryo-EM structure, cross-links, and distances from in vivo fluorescence microscopy. Our subunit configuration is consistent with the cryo-EM structure, except for Sec5. While not observed in the cryo-EM map, the integrative model localizes the N-terminal half of Sec3 near the Sec6 subunit. Limited proteolysis experiments suggest that the conformation of Exo70 is dynamic, which may have functional implications for SNARE and membrane interactions. This study illustrates how integrative modeling based on varied low-resolution structural data can inform biologically relevant hypotheses, even in the absence of high-resolution data.
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Affiliation(s)
- Sai J Ganesan
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Michael J Feyder
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Ilan E Chemmama
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Fei Fang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York, USA
| | - Yi Shi
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
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27
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Roy Chowdhury S, Bhattacharjee C, Casler JC, Jain BK, Glick BS, Bhattacharyya D. ER arrival sites associate with ER exit sites to create bidirectional transport portals. J Cell Biol 2020; 219:e201902114. [PMID: 32328626 PMCID: PMC7147096 DOI: 10.1083/jcb.201902114] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/11/2019] [Accepted: 01/17/2020] [Indexed: 01/30/2023] Open
Abstract
COPI vesicles mediate Golgi-to-ER recycling, but COPI vesicle arrival sites at the ER have been poorly defined. We explored this issue using the yeast Pichia pastoris. ER arrival sites (ERAS) can be visualized by labeling COPI vesicle tethers such as Tip20. Our results place ERAS at the periphery of COPII-labeled ER export sites (ERES). The dynamics of ERES and ERAS are indistinguishable, indicating that these structures are tightly coupled. Displacement or degradation of Tip20 does not alter ERES organization, whereas displacement or degradation of either COPII or COPI components disrupts ERAS organization. We infer that Golgi compartments form at ERES and then produce COPI vesicles to generate ERAS. As a result, ERES and ERAS are functionally linked to create bidirectional transport portals at the ER-Golgi interface. COPI vesicles likely become tethered while they bud, thereby promoting efficient retrograde transport. In mammalian cells, the Tip20 homologue RINT1 associates with ERES, indicating possible conservation of the link between ERES and ERAS.
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Affiliation(s)
- Sudeshna Roy Chowdhury
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer, Tata Memorial Centre, Navi Mumbai, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, India
| | - Chumki Bhattacharjee
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer, Tata Memorial Centre, Navi Mumbai, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, India
| | - Jason C. Casler
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL
| | - Bhawik Kumar Jain
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer, Tata Memorial Centre, Navi Mumbai, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, India
| | - Benjamin S. Glick
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL
| | - Dibyendu Bhattacharyya
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer, Tata Memorial Centre, Navi Mumbai, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, India
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28
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Affiliation(s)
- Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster
- Cells-in-Motion Cluster of Excellence (EXC 1003—CiM), University of Münster
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29
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Travis SM, Kokona B, Fairman R, Hughson FM. Roles of singleton tryptophan motifs in COPI coat stability and vesicle tethering. Proc Natl Acad Sci U S A 2019; 116:24031-24040. [PMID: 31712447 PMCID: PMC6883825 DOI: 10.1073/pnas.1909697116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coat protein I (COPI)-coated vesicles mediate retrograde transport from the Golgi to the endoplasmic reticulum (ER), as well as transport within the Golgi. Major progress has been made in defining the structure of COPI coats, in vitro and in vivo, at resolutions as high as 9 Å. Nevertheless, important questions remain unanswered, including what specific interactions stabilize COPI coats, how COPI vesicles recognize their target membranes, and how coat disassembly is coordinated with vesicle fusion and cargo delivery. Here, we use X-ray crystallography to identify a conserved site on the COPI subunit α-COP that binds to flexible, acidic sequences containing a single tryptophan residue. One such sequence, found within α-COP itself, mediates α-COP homo-oligomerization. Another such sequence is contained within the lasso of the ER-resident Dsl1 complex, where it helps mediate the tethering of Golgi-derived COPI vesicles at the ER membrane. Together, our findings suggest that α-COP homo-oligomerization plays a key role in COPI coat stability, with potential implications for the coordination of vesicle tethering, uncoating, and fusion.
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Affiliation(s)
- Sophie M Travis
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Bashkim Kokona
- Department of Biology, Haverford College, Haverford, PA 19041
- Department of Chemistry, Haverford College, Haverford, PA 19041
| | - Robert Fairman
- Department of Biology, Haverford College, Haverford, PA 19041
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30
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Staufner C, Peters B, Wagner M, Alameer S, Barić I, Broué P, Bulut D, Church JA, Crushell E, Dalgıç B, Das AM, Dick A, Dikow N, Dionisi-Vici C, Distelmaier F, Bozbulut NE, Feillet F, Gonzales E, Hadzic N, Hauck F, Hegarty R, Hempel M, Herget T, Klein C, Konstantopoulou V, Kopajtich R, Kuster A, Laass MW, Lainka E, Larson-Nath C, Leibner A, Lurz E, Mayr JA, McKiernan P, Mention K, Moog U, Mungan NO, Riedhammer KM, Santer R, Palafoll IV, Vockley J, Westphal DS, Wiedemann A, Wortmann SB, Diwan GD, Russell RB, Prokisch H, Garbade SF, Kölker S, Hoffmann GF, Lenz D. Defining clinical subgroups and genotype–phenotype correlations in NBAS-associated disease across 110 patients. Genet Med 2019; 22:610-621. [DOI: 10.1038/s41436-019-0698-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/30/2019] [Accepted: 10/30/2019] [Indexed: 12/16/2022] Open
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31
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Gillingham AK, Munro S. Transport carrier tethering - how vesicles are captured by organelles. Curr Opin Cell Biol 2019; 59:140-146. [PMID: 31154044 DOI: 10.1016/j.ceb.2019.04.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/16/2019] [Accepted: 04/24/2019] [Indexed: 12/20/2022]
Abstract
All cells contain numerous membrane-bound organelles that carry out specific functions. These compartments do not, however, act in isolation. Some are in direct contact via membrane contact sites, while others exchange material via specific vesicles or tubular carriers laden with cargo. The term tethering in the context of this review is used to describe the primary recognition and docking of transport carriers with acceptor organelles that occurs before SNARE engagement and membrane fusion. However, it is important to note that other tethering events occur, for example, between organelles in direct contact, which do not lead to fusion.
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Affiliation(s)
- Alison K Gillingham
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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32
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Ungermann C, Kümmel D. Structure of membrane tethers and their role in fusion. Traffic 2019; 20:479-490. [DOI: 10.1111/tra.12655] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/26/2019] [Accepted: 05/03/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Christian Ungermann
- Biochemistry Section, Department of Biology/ChemistryUniversity of Osnabrück Osnabrück Germany
- Center for Cellular Nanoanalytics (CellNanOs)University of Osnabrück Osnabrück Germany
| | - Daniel Kümmel
- Biochemistry & Structural Biology Section, Institute of BiochemistryUniversity of Münster Münster Germany
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33
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van der Beek J, Jonker C, van der Welle R, Liv N, Klumperman J. CORVET, CHEVI and HOPS – multisubunit tethers of the endo-lysosomal system in health and disease. J Cell Sci 2019; 132:132/10/jcs189134. [DOI: 10.1242/jcs.189134] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
ABSTRACT
Multisubunit tethering complexes (MTCs) are multitasking hubs that form a link between membrane fusion, organelle motility and signaling. CORVET, CHEVI and HOPS are MTCs of the endo-lysosomal system. They regulate the major membrane flows required for endocytosis, lysosome biogenesis, autophagy and phagocytosis. In addition, individual subunits control complex-independent transport of specific cargoes and exert functions beyond tethering, such as attachment to microtubules and SNARE activation. Mutations in CHEVI subunits lead to arthrogryposis, renal dysfunction and cholestasis (ARC) syndrome, while defects in CORVET and, particularly, HOPS are associated with neurodegeneration, pigmentation disorders, liver malfunction and various forms of cancer. Diseases and phenotypes, however, vary per affected subunit and a concise overview of MTC protein function and associated human pathologies is currently lacking. Here, we provide an integrated overview on the cellular functions and pathological defects associated with CORVET, CHEVI or HOPS proteins, both with regard to their complexes and as individual subunits. The combination of these data provides novel insights into how mutations in endo-lysosomal proteins lead to human pathologies.
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Affiliation(s)
- Jan van der Beek
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Institute for Biomembranes, Utrecht University, Utrecht 3584 CX, The Netherlands
| | - Caspar Jonker
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Institute for Biomembranes, Utrecht University, Utrecht 3584 CX, The Netherlands
| | - Reini van der Welle
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Institute for Biomembranes, Utrecht University, Utrecht 3584 CX, The Netherlands
| | - Nalan Liv
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Institute for Biomembranes, Utrecht University, Utrecht 3584 CX, The Netherlands
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Institute for Biomembranes, Utrecht University, Utrecht 3584 CX, The Netherlands
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34
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Jackson CL. Lipid droplet biogenesis. Curr Opin Cell Biol 2019; 59:88-96. [PMID: 31075519 DOI: 10.1016/j.ceb.2019.03.018] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/24/2019] [Accepted: 03/29/2019] [Indexed: 11/18/2022]
Abstract
Lipid droplets (LDs) store neutral lipids in their core as an energy source when nutrients are scarce. The center of an LD is hydrophobic, and hence it is surrounded by a phospholipid monolayer, unlike other organelles that have an aqueous interior and are bounded by a phospholipid bilayer. LDs arise from the ER, where neutral lipid synthesis enzymes are localized. A combination of biophysical analysis and modeling, in vitro reconstitution and cell biological analyses has provided a great deal of information over the past few years on the process of LD biogenesis from the ER. In addition to lipid composition, four protein families (seipin proteins, perilipins, FIT proteins and ER shaping proteins) are crucial for LD biogenesis. Recent studies have shown that LDs preferentially arise, along with peroxisomes, at special ER sites marked by the reticulon-like Pex30/MCTP2 protein. New functions for perilipins and FIT family proteins have been uncovered, and the cryo-electron microscopy structure of seipin coupled with high resolution imaging in cells has provided a more comprehensive picture of its function in LD biogenesis. Seipin, along with other proteins such as Rab18 and its effector NRZ, have been shown to carry out their functions at least in part through regulation of ER-LD contact sites, whose establishment and maintenance have emerged as an essential component of LD biogenesis and maturation.
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Affiliation(s)
- Catherine L Jackson
- Institut Jacques Monod, UMR7592 CNRS Université Paris-Diderot, Sorbonne Paris Cité, Paris, France.
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35
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Koike S, Jahn R. SNAREs define targeting specificity of trafficking vesicles by combinatorial interaction with tethering factors. Nat Commun 2019; 10:1608. [PMID: 30962439 PMCID: PMC6453939 DOI: 10.1038/s41467-019-09617-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 03/15/2019] [Indexed: 02/06/2023] Open
Abstract
Membrane traffic operates by vesicles that bud from precursor organelles and are transported to their target compartment where they dock and fuse. Targeting requires tethering factors recruited by small GTPases and phosphoinositides whereas fusion is carried out by SNARE proteins. Here we report that vesicles containing the Q-SNAREs syntaxin 13 (Stx13) and syntaxin 6 (Stx6) together are targeted to a different endosomal compartment than vesicles containing only Stx6 using injection of artificial vesicles. Targeting by Stx6 requires Vps51, a component of the GARP/EARP tethering complexes. In contrast, targeting by both Stx6 and Stx13 is governed by Vps13B identified here as tethering factor functioning in transport from early endosomes to recycling endosomes. Vps13B specifically binds to Stx13/Stx6 as well as to Rab14, Rab6, and PtdIns(3)P. We conclude that SNAREs use a combinatorial code for recruiting tethering factors, revealing a key function in targeting that is independent of SNARE pairing during fusion. Intracellular vesicle targeting is mediated by Rab GTPases that cooperate with phosphatidylinositides and SNARE proteins, which then facilitate membrane fusion. Here, the authors microinject artificial vesicles into HeLa cells and find that SNAREs play a more prominent role in targeting specificity of trafficking vesicles than previously known.
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Affiliation(s)
- Seiichi Koike
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, 37077, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, 37077, Germany.
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36
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Wang S, Li Y, Gong J, Ye S, Yang X, Zhang R, Ma C. Munc18 and Munc13 serve as a functional template to orchestrate neuronal SNARE complex assembly. Nat Commun 2019; 10:69. [PMID: 30622273 PMCID: PMC6325239 DOI: 10.1038/s41467-018-08028-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/12/2018] [Indexed: 11/30/2022] Open
Abstract
The transition of the Munc18-1/syntaxin-1 complex to the SNARE complex, a key step involved in exocytosis, is regulated by Munc13-1, SNAP-25 and synaptobrevin-2, but the underlying mechanism remains elusive. Here, we identify an interaction between Munc13-1 and the membrane-proximal linker region of synaptobrevin-2, and reveal its essential role in transition and exocytosis. Upon this interaction, Munc13-1 not only recruits synaptobrevin-2-embedded vesicles to the target membrane but also renders the synaptobrevin-2 SNARE motif more accessible to the Munc18-1/syntaxin-1 complex. Afterward, the entry of SNAP-25 leads to a half-zippered SNARE assembly, which eventually dissociates the Munc18-1/syntaxin-1 complex to complete SNARE complex formation. Our data suggest that Munc18-1 and Munc13-1 together serve as a functional template to orchestrate SNARE complex assembly. Synaptic exocytosis depends on formation of the SNARE complex but its assembly mechanism is still under debate. Here, the authors identify an interaction between Munc13-1 and synaptobrevin-2 that is critical for the transition of the Munc18-1/syntaxin-1 complex to the SNARE complex.
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Affiliation(s)
- Shen Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Yun Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Jihong Gong
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Sheng Ye
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Xiaofei Yang
- Key Laboratory of Cognitive Science, Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis and Treatment, Laboratory of Membrane Ion Channels and Medicine, College of Biomedical Engineering, South-Central University for Nationalities, 430074, Wuhan, China
| | - Rongguang Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,National Center for Protein Science Shanghai, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, 201203, Shanghai, China
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, 430074, Wuhan, China.
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37
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Lepore DM, Martínez-Núñez L, Munson M. Exposing the Elusive Exocyst Structure. Trends Biochem Sci 2018; 43:714-725. [PMID: 30055895 PMCID: PMC6108956 DOI: 10.1016/j.tibs.2018.06.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 06/18/2018] [Accepted: 06/29/2018] [Indexed: 11/18/2022]
Abstract
A major challenge for a molecular understanding of membrane trafficking has been the elucidation of high-resolution structures of large, multisubunit tethering complexes that spatially and temporally control intracellular membrane fusion. Exocyst is a large hetero-octameric protein complex proposed to tether secretory vesicles at the plasma membrane to provide quality control of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated membrane fusion. Breakthroughs in methodologies, including sample preparation, biochemical characterization, fluorescence microscopy, and single-particle cryoelectron microscopy, are providing critical insights into the structure and function of the exocyst. These studies now pose more questions than answers for understanding fundamental functional mechanisms, and they open wide the door for future studies to elucidate interactions with protein and membrane partners, potential conformational changes, and molecular insights into tethering reactions.
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Affiliation(s)
- Dante M Lepore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Leonora Martínez-Núñez
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
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38
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Morlon-Guyot J, El Hajj H, Martin K, Fois A, Carrillo A, Berry L, Burchmore R, Meissner M, Lebrun M, Daher W. A proteomic analysis unravels novel CORVET and HOPS proteins involved in Toxoplasma gondii
secretory organelles biogenesis. Cell Microbiol 2018; 20:e12870. [DOI: 10.1111/cmi.12870] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/23/2018] [Accepted: 06/05/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Juliette Morlon-Guyot
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Hiba El Hajj
- Departments of Internal Medicine and Experimental Pathology, Immunology and Microbiology; American University of Beirut; Beirut Lebanon
| | - Kevin Martin
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Adrien Fois
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Amandine Carrillo
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Laurence Berry
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | | | - Markus Meissner
- Wellcome Centre for Molecular Parasitology; University of Glasgow; Glasgow UK
- Department of Veterinary Sciences, Experimental Parasitology; Ludwig-Maximilians-Universität München; Munich Germany
| | - Maryse Lebrun
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
| | - Wassim Daher
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS, INSERM; Université de Montpellier; Montpellier France
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39
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Zhao X, Guo X, Tang X, Zhang H, Wang M, Kong Y, Zhang X, Zhao Z, Lv M, Li L. Misregulation of ER-Golgi Vesicle Transport Induces ER Stress and Affects Seed Vigor and Stress Response. FRONTIERS IN PLANT SCIENCE 2018; 9:658. [PMID: 29868102 PMCID: PMC5968616 DOI: 10.3389/fpls.2018.00658] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/30/2018] [Indexed: 05/20/2023]
Abstract
Seeds of higher plants accumulate numerous storage proteins to use as nitrogen resources for early plant development. Seed storage proteins (SSPs) are synthesized as large precursors on the rough endoplasmic reticulum (rER), and are delivered to protein storage vacuoles (PSVs) via vesicle transport, where they are processed to mature forms. We previously identified an Arabidopsis ER-localized tethering complex, MAG2 complex, which might be involved in Golgi to ER retrograde transport. The MAG2 complex is composed of 4 subunits, MAG2, MIP1, MIP2, and MIP3. Mutants with defective alleles for these subunits accumulated SSP precursors inside the ER lumen. Here, we report that the mag2-1 mip3-1 and mip2-1 mip3-1 double mutant have more serious vesicle transport defects than the mag2-1, mip2-1, and mip3-1 single mutants, since they accumulate more SSP precursors than the corresponding single mutants, and ER stress is more severe than the single mutants. The mag2-1 mip3-1 and mip2-1 mip3-1 double mutants show growth and developmental defects rather than the single mutants. Both single and double mutant seeds are found to have lower protein content and decreased germinating vigor than wild type seeds. All the mutants are sensitive to abscisic acid (ABA) and salt stress, and exhibit alteration in ABA signaling pathway. Our study clarified that ER-Golgi vesicle transport affects seed vigor through controlling seed protein quality and content, as well as plant response to environmental stress via influencing ABA signaling pathway.
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Affiliation(s)
- Xiaonan Zhao
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Xiufen Guo
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Xiaofei Tang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
- Institute of Soybean Research, Heilongjiang Provincial Academy of Agricultural Sciences, Harbin, China
| | - Hailong Zhang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Mingjing Wang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Yun Kong
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Xiaomeng Zhang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Zhenjie Zhao
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Min Lv
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
| | - Lixin Li
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Harbin, China
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40
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Assembly-hub function of ER-localized SNARE proteins in biogenesis of tombusvirus replication compartment. PLoS Pathog 2018; 14:e1007028. [PMID: 29746582 PMCID: PMC5963807 DOI: 10.1371/journal.ppat.1007028] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 05/22/2018] [Accepted: 04/13/2018] [Indexed: 01/28/2023] Open
Abstract
Positive-strand RNA viruses assemble numerous membrane-bound viral replicase complexes within large replication compartments to support their replication in infected cells. Yet the detailed mechanism of how given subcellular compartments are subverted by viruses is incompletely understood. Although, Tomato bushy stunt virus (TBSV) uses peroxisomal membranes for replication, in this paper, we show evidence that the ER-resident SNARE (soluble NSF attachment protein receptor) proteins play critical roles in the formation of active replicase complexes in yeast model host and in plants. Depletion of the syntaxin 18-like Ufe1 and Use1, which are components of the ER SNARE complex in the ERAS (ER arrival site) subdomain, in yeast resulted in greatly reduced tombusvirus accumulation. Over-expression of a dominant-negative mutant of either the yeast Ufe1 or the orthologous plant Syp81 syntaxin greatly interferes with tombusvirus replication in yeast and plants, thus further supporting the role of this host protein in tombusvirus replication. Moreover, tombusvirus RNA replication was low in cell-free extracts from yeast with repressed Ufe1 or Use1 expression. We also present evidence for the mislocalization of the tombusviral p33 replication protein to the ER membrane in Ufe1p-depleted yeast cells. The viral p33 replication protein interacts with both Ufe1p and Use1p and co-opts them into the TBSV replication compartment in yeast and plant cells. The co-opted Ufe1 affects the virus-driven membrane contact site formation, sterol-enrichment at replication sites, recruitment of several pro-viral host factors and subversion of the Rab5-positive PE-rich endosomes needed for robust TBSV replication. In summary, we demonstrate a critical role for Ufe1 and Use1 SNARE proteins in TBSV replication and propose that the pro-viral functions of Ufe1 and Use1 are to serve as assembly hubs for the formation of the extensive TBSV replication compartments in cells. Altogether, these findings point clearly at the ERAS subdomain of ER as a critical site for the biogenesis of the TBSV replication compartment. Viral replication organelles are formed in subcellular compartments during positive-strand RNA virus infections to support robust virus replication. TBSV induces multivesicular body-like structures consisting of aggregated peroxisomes. However, endoplasmic reticulum (ER) and early endosomal proteins and membranes also contribute to the biogenesis of the replication compartment. The authors show that the syntaxin 18-like Ufe1 and Use1 ER SNARE proteins, which are present in ER subdomains called ERAS (ER arrival site), are necessary for the formation of the viral replication organelles. By binding to the p33 replication protein of TBSV, Ufe1 and Use1 serve as an assembly hub for biogenesis of the replication compartment and facilitating the transfer of phospholipids and sterols to the growing sites of viral replication. The advantage of co-opting ER resident SNAREs could be that these proteins constitute very active ER subdomains (ERAS), which might be especially suitable for generation of the extensive membranous viral replication compartment.
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Abstract
Plant vacuoles are multifunctional organelles. On the one hand, most vegetative tissues develop lytic vacuoles that have a role in degradation. On the other hand, seed cells have two types of storage vacuoles: protein storage vacuoles (PSVs) in endosperm and embryonic cells and metabolite storage vacuoles in seed coats. Vacuolar proteins and metabolites are synthesized on the endoplasmic reticulum and then transported to the vacuoles via Golgi-dependent and Golgi-independent pathways. Proprotein precursors delivered to the vacuoles are converted into their respective mature forms by vacuolar processing enzyme, which also regulates various kinds of programmed cell death in plants. We summarize two types of vacuolar membrane dynamics that occur during defense responses: vacuolar membrane collapse to attack viral pathogens and fusion of vacuolar and plasma membranes to attack bacterial pathogens. We also describe the chemical defense against herbivores brought about by the presence of PSVs in the idioblast myrosin cell.
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Affiliation(s)
- Tomoo Shimada
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;
| | - Junpei Takagi
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;
- Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
| | - Takuji Ichino
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji 611-0011, Japan
| | - Makoto Shirakawa
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Ikuko Hara-Nishimura
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
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42
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Abstract
The coat protein complex I (COPI) allows the precise sorting of lipids and proteins between Golgi cisternae and retrieval from the Golgi to the ER. This essential role maintains the identity of the early secretory pathway and impinges on key cellular processes, such as protein quality control. In this Cell Science at a Glance and accompanying poster, we illustrate the different stages of COPI-coated vesicle formation and revisit decades of research in the context of recent advances in the elucidation of COPI coat structure. By calling attention to an array of questions that have remained unresolved, this review attempts to refocus the perspectives of the field.
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Affiliation(s)
- Eric C Arakel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany .,Max-Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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43
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Raote I, Ortega-Bellido M, Santos AJ, Foresti O, Zhang C, Garcia-Parajo MF, Campelo F, Malhotra V. TANGO1 builds a machine for collagen export by recruiting and spatially organizing COPII, tethers and membranes. eLife 2018. [PMID: 29513218 PMCID: PMC5851698 DOI: 10.7554/elife.32723] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Collagen export from the endoplasmic reticulum (ER) requires TANGO1, COPII coats, and retrograde fusion of ERGIC membranes. How do these components come together to produce a transport carrier commensurate with the bulky cargo collagen? TANGO1 is known to form a ring that corrals COPII coats, and we show here how this ring or fence is assembled. Our data reveal that a TANGO1 ring is organized by its radial interaction with COPII, and lateral interactions with cTAGE5, TANGO1-short or itself. Of particular interest is the finding that TANGO1 recruits ERGIC membranes for collagen export via the NRZ (NBAS/RINT1/ZW10) tether complex. Therefore, TANGO1 couples retrograde membrane flow to anterograde cargo transport. Without the NRZ complex, the TANGO1 ring does not assemble, suggesting its role in nucleating or stabilising this process. Thus, coordinated capture of COPII coats, cTAGE5, TANGO1-short, and tethers by TANGO1 assembles a collagen export machine at the ER.
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Affiliation(s)
- Ishier Raote
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Maria Ortega-Bellido
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - António Jm Santos
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Ombretta Foresti
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Chong Zhang
- SIMBIOsys Group, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Maria F Garcia-Parajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | - Vivek Malhotra
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
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44
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Xu D, Li Y, Wu L, Li Y, Zhao D, Yu J, Huang T, Ferguson C, Parton RG, Yang H, Li P. Rab18 promotes lipid droplet (LD) growth by tethering the ER to LDs through SNARE and NRZ interactions. J Cell Biol 2018; 217:975-995. [PMID: 29367353 PMCID: PMC5839781 DOI: 10.1083/jcb.201704184] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 10/12/2017] [Accepted: 12/22/2017] [Indexed: 12/16/2022] Open
Abstract
Lipid incorporation from endoplasmic reticulum (ER) to lipid droplet (LD) is important in controlling LD growth and intracellular lipid homeostasis. However, the molecular link mediating ER and LD cross talk remains elusive. Here, we identified Rab18 as an important Rab guanosine triphosphatase in controlling LD growth and maturation. Rab18 deficiency resulted in a drastically reduced number of mature LDs and decreased lipid storage, and was accompanied by increased ER stress. Rab3GAP1/2, the GEF of Rab18, promoted LD growth by activating and targeting Rab18 to LDs. LD-associated Rab18 bound specifically to the ER-associated NAG-RINT1-ZW10 (NRZ) tethering complex and their associated SNAREs (Syntaxin18, Use1, BNIP1), resulting in the recruitment of ER to LD and the formation of direct ER-LD contact. Cells with defects in the NRZ/SNARE complex function showed reduced LD growth and lipid storage. Overall, our data reveal that the Rab18-NRZ-SNARE complex is critical protein machinery for tethering ER-LD and establishing ER-LD contact to promote LD growth.
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Affiliation(s)
- Dijin Xu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuqi Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lizhen Wu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ying Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Dongyu Zhao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jinhai Yu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Tuozhi Huang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Charles Ferguson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia.,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Peng Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
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45
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Liu D, Li X, Shen D, Novick P. Two subunits of the exocyst, Sec3p and Exo70p, can function exclusively on the plasma membrane. Mol Biol Cell 2018; 29:736-750. [PMID: 29343551 PMCID: PMC6003224 DOI: 10.1091/mbc.e17-08-0518] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 11/18/2022] Open
Abstract
The exocyst is an octameric complex that tethers secretory vesicles to the plasma membrane in preparation for fusion. We anchored each subunit with a transmembrane (TM) domain at its N- or C-terminus. Only N-terminally anchored TM-Sec3p and C-terminally anchored Exo70p-TM proved functional. These findings orient the complex with respect to the membrane and establish that Sec3p and Exo70p can function exclusively on the membrane. The functions of TM-Sec3p and Exo70p-TM were largely unaffected by blocks in endocytic recycling, suggesting that they act on the plasma membrane rather than on secretory vesicles. Cytosolic pools of the other exocyst subunits were unaffected in TM-sec3 cells, while they were partially depleted in exo70-TM cells. Blocking actin-dependent delivery of secretory vesicles in act1-3 cells results in loss of Sec3p from the purified complex. Our results are consistent with a model in which Sec3p and Exo70p can function exclusively on the plasma membrane while the other subunits are brought to them on secretory vesicles.
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Affiliation(s)
- Dongmei Liu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
| | - Xia Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
| | - David Shen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
| | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92130
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46
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TFG facilitates outer coat disassembly on COPII transport carriers to promote tethering and fusion with ER-Golgi intermediate compartments. Proc Natl Acad Sci U S A 2017; 114:E7707-E7716. [PMID: 28851831 DOI: 10.1073/pnas.1709120114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The conserved coat protein complex II (COPII) mediates the initial steps of secretory protein trafficking by assembling onto subdomains of the endoplasmic reticulum (ER) in two layers to generate cargo-laden transport carriers that ultimately fuse with an adjacent ER-Golgi intermediate compartment (ERGIC). Here, we demonstrate that Trk-fused gene (TFG) binds directly to the inner layer of the COPII coat. Specifically, the TFG C terminus interacts with Sec23 through a shared interface with the outer COPII coat and the cargo receptor Tango1/cTAGE5. Our findings indicate that TFG binding to Sec23 outcompetes these other associations in a concentration-dependent manner and ultimately promotes outer coat dissociation. Additionally, we demonstrate that TFG tethers vesicles harboring the inner COPII coat, which contributes to their clustering between the ER and ERGIC in cells. Together, our studies define a mechanism by which COPII transport carriers are retained locally at the ER/ERGIC interface after outer coat disassembly, which is a prerequisite for fusion with ERGIC membranes.
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47
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Anderson NS, Mukherjee I, Bentivoglio CM, Barlowe C. The Golgin protein Coy1 functions in intra-Golgi retrograde transport and interacts with the COG complex and Golgi SNAREs. Mol Biol Cell 2017; 28:mbc.E17-03-0137. [PMID: 28794270 PMCID: PMC5620376 DOI: 10.1091/mbc.e17-03-0137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 07/12/2017] [Accepted: 07/31/2017] [Indexed: 01/09/2023] Open
Abstract
Extended coiled-coil proteins of the Golgin family play prominent roles in maintaining the structure and function of the Golgi complex. Here we further investigate the Golgin protein Coy1 and document its function in retrograde transport between early Golgi compartments. Cells that lack Coy1 displayed a reduced half-life of the Och1 mannosyltransferase, an established cargo of intra-Golgi retrograde transport. Combining the coy1Δ mutation with deletions in other putative retrograde Golgins (sgm1Δ and rud3Δ) caused strong glycosylation and growth defects and reduced membrane association of the Conserved Oligomeric Golgi complex. In contrast, overexpression of COY1 inhibited the growth of mutant strains deficient in fusion activity at the Golgi (sed5-1 and sly1-ts). To map Coy1 protein interactions, co-immunoprecipitation experiments revealed an association with the Conserved Oliogmeric Golgi (COG) complex and with intra-Golgi SNARE proteins. These physical interactions are direct, as Coy1 was efficiently captured in vitro by Lobe A of the COG complex and the purified SNARE proteins Gos1, Sed5 and Sft1. Thus, our genetic, in vivo, and biochemical data indicate a role for Coy1 in regulating COG complex-dependent fusion of retrograde-directed COPI vesicles.
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Affiliation(s)
- Nadine S Anderson
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Indrani Mukherjee
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Christine M Bentivoglio
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Charles Barlowe
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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48
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Identification of Rab18 as an Essential Host Factor for BK Polyomavirus Infection Using a Whole-Genome RNA Interference Screen. mSphere 2017; 2:mSphere00291-17. [PMID: 28815213 PMCID: PMC5555678 DOI: 10.1128/mspheredirect.00291-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 07/12/2017] [Indexed: 11/20/2022] Open
Abstract
Polyomaviruses bind to a group of specific gangliosides on the plasma membrane of the cell prior to being endocytosed. They then follow a retrograde trafficking pathway to reach the endoplasmic reticulum (ER). The viruses begin to disassemble in the ER and then exit the ER and move to the nucleus. However, the details of intracellular trafficking between the endosome and the ER are largely unknown. By implementing a whole human genome small interfering RNA screen, we identified Rab18, syntaxin 18, and the NRZ complex as key components in endosome-ER trafficking of the human polyomavirus BKPyV. These results serve to further elucidate the route BKPyV takes from outside the cell to its site of replication in the nucleus. BK polyomavirus (BKPyV) is a human pathogen first isolated in 1971. BKPyV infection is ubiquitous in the human population, with over 80% of adults worldwide being seropositive for BKPyV. BKPyV infection is usually asymptomatic; however, BKPyV reactivation in immunosuppressed transplant patients causes two diseases, polyomavirus-associated nephropathy and hemorrhagic cystitis. To establish a successful infection in host cells, BKPyV must travel in retrograde transport vesicles to reach the nucleus. To make this happen, BKPyV requires the cooperation of host cell proteins. To further identify host factors associated with BKPyV entry and intracellular trafficking, we performed a whole-genome small interfering RNA screen on BKPyV infection of primary human renal proximal tubule epithelial cells. The results revealed the importance of Ras-related protein Rab18 and syntaxin 18 for BKPyV infection. Our subsequent experiments implicated additional factors that interact with this pathway and suggest a more detailed model of the intracellular trafficking process, indicating that BKPyV reaches the endoplasmic reticulum (ER) lumen through a retrograde transport pathway between the late endosome and the ER. IMPORTANCE Polyomaviruses bind to a group of specific gangliosides on the plasma membrane of the cell prior to being endocytosed. They then follow a retrograde trafficking pathway to reach the endoplasmic reticulum (ER). The viruses begin to disassemble in the ER and then exit the ER and move to the nucleus. However, the details of intracellular trafficking between the endosome and the ER are largely unknown. By implementing a whole human genome small interfering RNA screen, we identified Rab18, syntaxin 18, and the NRZ complex as key components in endosome-ER trafficking of the human polyomavirus BKPyV. These results serve to further elucidate the route BKPyV takes from outside the cell to its site of replication in the nucleus.
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Brandizzi F. Transport from the endoplasmic reticulum to the Golgi in plants: Where are we now? Semin Cell Dev Biol 2017; 80:94-105. [PMID: 28688928 DOI: 10.1016/j.semcdb.2017.06.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/11/2017] [Accepted: 06/27/2017] [Indexed: 11/26/2022]
Abstract
The biogenesis of about one third of the cellular proteome is initiated in the endoplasmic reticulum (ER), which exports proteins to the Golgi apparatus for sorting to their final destination. Notwithstanding the close proximity of the ER with other secretory membranes (e.g., endosomes, plasma membrane), the ER is also important for the homeostasis of non-secretory organelles such as mitochondria, peroxisomes, and chloroplasts. While how the plant ER interacts with most of the non-secretory membranes is largely unknown, the knowledge on the mechanisms for ER-to-Golgi transport is relatively more advanced. Indeed, over the last fifteen years or so, a large number of exciting results have contributed to draw parallels with non-plant species but also to highlight the complexity of the plant ER-Golgi interface, which bears unique features. This review reports and discusses results on plant ER-to-Golgi traffic, focusing mainly on research on COPII-mediated transport in the model species Arabidopsis thaliana.
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Affiliation(s)
- Federica Brandizzi
- MSU-DOE Plant Research Lab and Plant Biology Department, Michigan State University, East Lansing, MI 48824, USA; Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA.
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Yue P, Zhang Y, Mei K, Wang S, Lesigang J, Zhu Y, Dong G, Guo W. Sec3 promotes the initial binary t-SNARE complex assembly and membrane fusion. Nat Commun 2017; 8:14236. [PMID: 28112172 PMCID: PMC5267525 DOI: 10.1038/ncomms14236] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 12/12/2016] [Indexed: 01/04/2023] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor-attachment protein receptors (SNAREs) constitute the core machinery for membrane fusion during eukaryotic cell vesicular trafficking. However, how the assembly of the SNARE complex is initiated is unknown. Here we report that Sec3, a component of the exocyst complex that mediates vesicle tethering during exocytosis, directly interacts with the t-SNARE protein Sso2. This interaction promotes the formation of an Sso2-Sec9 'binary' t-SNARE complex, the early rate-limiting step in SNARE complex assembly, and stimulates membrane fusion. The crystal structure of the Sec3-Sso2 complex suggests that Sec3 binding induces conformational changes of Sso2 that are crucial for the relief of its auto-inhibition. Interestingly, specific disruption of the Sec3-Sso2 interaction in cells blocks exocytosis without affecting the function of Sec3 in vesicle tethering. Our study reveals an activation mechanism for SNARE complex assembly, and uncovers a role of the exocyst in promoting membrane fusion in addition to vesicle tethering.
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Affiliation(s)
- Peng Yue
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Yubo Zhang
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, 1030 Vienna, Austria
| | - Kunrong Mei
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Shaoxiao Wang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Johannes Lesigang
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, 1030 Vienna, Austria
| | - Yueyao Zhu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Gang Dong
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, 1030 Vienna, Austria
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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