1
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Feathers JR, Vignogna RC, Fromme JC. Structural basis for Rab6 activation by the Ric1-Rgp1 complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.06.592747. [PMID: 38766083 PMCID: PMC11100747 DOI: 10.1101/2024.05.06.592747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Rab GTPases act as molecular switches to regulate organelle homeostasis and membrane trafficking. Rab6 plays a central role in regulating cargo flux through the Golgi and is activated via nucleotide exchange by the Ric1-Rgp1 protein complex. Ric1-Rgp1 is conserved throughout eukaryotes but the structural and mechanistic basis for its function has not been established. Here we report the cryoEM structure of a Ric1-Rgp1-Rab6 complex representing a key intermediate of the nucleotide exchange reaction. This structure reveals the overall architecture of the complex and enabled us to identify interactions critical for proper recognition and activation of Rab6 on the Golgi membrane surface. Ric1-Rgp1 interacts with the nucleotide-binding domain of Rab6 using an uncharacterized helical domain, which we establish as a novel RabGEF domain by identifying residues required for Rab6 nucleotide exchange. Unexpectedly, the complex uses an arrestin fold to interact with the Rab6 hypervariable domain, indicating that interactions with the unstructured C-terminal regions of Rab GTPases may be a common specificity mechanism used by their activators. Collectively, our findings provide a detailed mechanistic understanding of regulated Rab6 activation at the Golgi.
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Affiliation(s)
- J. Ryan Feathers
- Department of Molecular Biology & Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850 USA
- Current address: 201 Schultz Laboratory, Princeton University, Princeton, NJ 08544 USA
| | - Ryan C. Vignogna
- Department of Molecular Biology & Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850 USA
| | - J. Christopher Fromme
- Department of Molecular Biology & Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14850 USA
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2
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Lai CC, Chiu WY, Chen YT, Wu CL, Lee FJS. The SNARE-associated protein Sft2 functions in Imh1-mediated SNARE recycling transport upon ER stress. Mol Biol Cell 2023; 34:ar112. [PMID: 37610835 PMCID: PMC10559307 DOI: 10.1091/mbc.e23-01-0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 08/07/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023] Open
Abstract
Vesicular trafficking involving SNARE proteins play a crucial role in the delivery of cargo to the target membrane. Arf-like protein 1 (Arl1) is an important regulator of the endosomal trans-Golgi network (TGN) and secretory trafficking. In yeast, ER stress-enhances Arl1 activation and Golgin Imh1 recruitment to the late-Golgi. Although Arl1 and Imh1 are critical for GARP-mediated endosomal SNARE-recycling transport in response to ER stress, their downstream effectors are unknown. Here, we report that the SNARE-associated protein Sft2 acts downstream of the Arl1-Imh1 axis to regulate SNARE recycling upon ER stress. We first demonstrated that Sft2 is required for Tlg1/Snc1 SNARE-recycling transport under tunicamycin-induced ER stress. Interestingly, we found that Imh1 regulates Tlg2 retrograde transport to the late-Golgi under ER stress, which in turn is required for Sft2 targeting to the late-Golgi. We further showed that Sft2 with 40 amino acids deleted from the N-terminus exhibits defective mediation of SNARE recycling and decreased association with Tlg1 under ER stress. Finally, we demonstrated that Sft2 is required for GARP-dependent endosome-to-Golgi transport in the absence of Rab protein Ypt6. This study highlights Sft2 as a critical downstream effector of the Arl1-Imh1 axis, mediating the endosome-to-Golgi transport of SNAREs.
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Affiliation(s)
- Chun-Chi Lai
- Institute of Molecular Medicine, National Taiwan University, Taipei 10002, Taiwan
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Wan-Yun Chiu
- Institute of Molecular Medicine, National Taiwan University, Taipei 10002, Taiwan
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Yan-Ting Chen
- Institute of Molecular Medicine, National Taiwan University, Taipei 10002, Taiwan
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chia-Lu Wu
- Institute of Molecular Medicine, National Taiwan University, Taipei 10002, Taiwan
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Fang-Jen S. Lee
- Institute of Molecular Medicine, National Taiwan University, Taipei 10002, Taiwan
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei 100, Taiwan
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3
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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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4
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Khakurel A, Lupashin VV. Role of GARP Vesicle Tethering Complex in Golgi Physiology. Int J Mol Sci 2023; 24:6069. [PMID: 37047041 PMCID: PMC10094427 DOI: 10.3390/ijms24076069] [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: 02/22/2023] [Revised: 03/17/2023] [Accepted: 03/19/2023] [Indexed: 04/14/2023] Open
Abstract
The Golgi associated retrograde protein complex (GARP) is an evolutionarily conserved component of Golgi membrane trafficking machinery that belongs to the Complexes Associated with Tethering Containing Helical Rods (CATCHR) family. Like other multisubunit tethering complexes such as COG, Dsl1, and Exocyst, the GARP is believed to function by tethering and promoting fusion of the endosome-derived small trafficking intermediate. However, even twenty years after its discovery, the exact structure and the functions of GARP are still an enigma. Recent studies revealed novel roles for GARP in Golgi physiology and identified human patients with mutations in GARP subunits. In this review, we summarized our knowledge of the structure of the GARP complex, its protein partners, GARP functions related to Golgi physiology, as well as cellular defects associated with the dysfunction of GARP subunits.
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Affiliation(s)
| | - Vladimir V. Lupashin
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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5
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Wang YH, Chiu WY, Chen YT, Cai PJ, Wu YC, Wu JL, Chen BH, Liu YW, Yu CJ, Lee FJS. Golgin Imh1 and GARP complex cooperate to restore the impaired SNARE recycling transport induced by ER stress. Cell Rep 2022; 38:110488. [PMID: 35320730 DOI: 10.1016/j.celrep.2022.110488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/11/2021] [Accepted: 02/14/2022] [Indexed: 11/03/2022] Open
Abstract
The accumulation of misfolded proteins in the endoplasmic reticulum (ER) induces the unfolded protein response (UPR), which acts through various mechanisms to reduce ER stress. While the UPR has been well studied for its effects on the ER, its impact on the Golgi is less understood. The Golgi complex receives transport vesicles from the endosome through two types of tethering factors: long coiled-coil golgin and the multisubunit Golgi-associated retrograde protein (GARP) complex. Here, we report that ER stress increases the phosphorylation of golgin Imh1 to maintain the GARP-mediated recycling of the SNAREs Snc1 and Tlg1. We also identify a specific function of the Golgi affected by ER stress and elucidate a homeostatic response to restore this function, which involves both an Ire1-dependent and a MAP kinase Slt2/ERK2-dependent mechanism. Furthermore, our findings advance a general understanding of how two different types of tethers act cooperatively to mediate a transport pathway.
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Affiliation(s)
| | | | | | | | - Yu-Chieh Wu
- Institute of Molecular Medicine, Taipei, Taiwan
| | - Jia-Lu Wu
- Institute of Molecular Medicine, Taipei, Taiwan
| | - Bo-Han Chen
- Institute of Molecular Medicine, Taipei, Taiwan
| | - Ya-Wen Liu
- Institute of Molecular Medicine, Taipei, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Jung Yu
- Department of Cell and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Thoracic Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Fang-Jen S Lee
- Institute of Molecular Medicine, Taipei, Taiwan; Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan.
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6
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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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7
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Humphreys IR, Pei J, Baek M, Krishnakumar A, Anishchenko I, Ovchinnikov S, Zhang J, Ness TJ, Banjade S, Bagde SR, Stancheva VG, Li XH, Liu K, Zheng Z, Barrero DJ, Roy U, Kuper J, Femández IS, Szakal B, Branzei D, Rizo J, Kisker C, Greene EC, Biggins S, Keeney S, Miller EA, Fromme JC, Hendrickson TL, Cong Q, Baker D. Computed structures of core eukaryotic protein complexes. Science 2021; 374:eabm4805. [PMID: 34762488 PMCID: PMC7612107 DOI: 10.1126/science.abm4805] [Citation(s) in RCA: 251] [Impact Index Per Article: 83.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Protein-protein interactions play critical roles in biology, but the structures of many eukaryotic protein complexes are unknown, and there are likely many interactions not yet identified. We take advantage of advances in proteome-wide amino acid coevolution analysis and deep-learning–based structure modeling to systematically identify and build accurate models of core eukaryotic protein complexes within the Saccharomyces cerevisiae proteome. We use a combination of RoseTTAFold and AlphaFold to screen through paired multiple sequence alignments for 8.3 million pairs of yeast proteins, identify 1505 likely to interact, and build structure models for 106 previously unidentified assemblies and 806 that have not been structurally characterized. These complexes, which have as many as five subunits, play roles in almost all key processes in eukaryotic cells and provide broad insights into biological function.
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Affiliation(s)
- Ian R. Humphreys
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Jimin Pei
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Minkyung Baek
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Aditya Krishnakumar
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Ivan Anishchenko
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Sergey Ovchinnikov
- Faculty of Arts and Sciences, Division of Science, Harvard University, Cambridge, MA, USA
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, USA
| | - Jing Zhang
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Travis J. Ness
- Department of Chemistry, Wayne State University, Detroit, MI, USA
| | - Sudeep Banjade
- Department of Molecular Biology & Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Saket R. Bagde
- Department of Molecular Biology & Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | | | - Xiao-Han Li
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Kaixian Liu
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Zhi Zheng
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, NY
| | - Daniel J. Barrero
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Upasana Roy
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Jochen Kuper
- Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Israel S. Femández
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Barnabas Szakal
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Dana Branzei
- IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100, Pavia, Italy
| | - Josep Rizo
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Caroline Kisker
- Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Eric C. Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Sue Biggins
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Scott Keeney
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, NY
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - J. Christopher Fromme
- Department of Molecular Biology & Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | | | - Qian Cong
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
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8
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D’Souza Z, Sumya FT, Khakurel A, Lupashin V. Getting Sugar Coating Right! The Role of the Golgi Trafficking Machinery in Glycosylation. Cells 2021; 10:cells10123275. [PMID: 34943782 PMCID: PMC8699264 DOI: 10.3390/cells10123275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 12/18/2022] Open
Abstract
The Golgi is the central organelle of the secretory pathway and it houses the majority of the glycosylation machinery, which includes glycosylation enzymes and sugar transporters. Correct compartmentalization of the glycosylation machinery is achieved by retrograde vesicular trafficking as the secretory cargo moves forward by cisternal maturation. The vesicular trafficking machinery which includes vesicular coats, small GTPases, tethers and SNAREs, play a major role in coordinating the Golgi trafficking thereby achieving Golgi homeostasis. Glycosylation is a template-independent process, so its fidelity heavily relies on appropriate localization of the glycosylation machinery and Golgi homeostasis. Mutations in the glycosylation enzymes, sugar transporters, Golgi ion channels and several vesicle tethering factors cause congenital disorders of glycosylation (CDG) which encompass a group of multisystem disorders with varying severities. Here, we focus on the Golgi vesicle tethering and fusion machinery, namely, multisubunit tethering complexes and SNAREs and their role in Golgi trafficking and glycosylation. This review is a comprehensive summary of all the identified CDG causing mutations of the Golgi trafficking machinery in humans.
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9
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Homma Y, Fukuda M. Knockout analysis of Rab6 effector proteins revealed the role of VPS52 in the secretory pathway. Biochem Biophys Res Commun 2021; 561:151-157. [PMID: 34023780 DOI: 10.1016/j.bbrc.2021.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 05/05/2021] [Indexed: 10/21/2022]
Abstract
Rab small GTPases regulate intracellular membrane trafficking by interacting with specific binding proteins called Rab effectors. Although Rab6 is implicated in basement membrane formation and secretory cargo trafficking, its precise regulatory mechanisms have remained largely unknown. In the present study we established five knockout cell lines for candidate Rab6 effectors and discovered that knockout of VPS52, a subunit of the GARP complex, resulted in attenuated secretion and lysosomal accumulation of secretory cargos, the same as Rab6-knockout does. We also evaluated the functional importance of the previously uncharacterized C-terminal region of VPS52 for restoring these phenotypes, as well as for the sorting of lysosomal proteins. Our findings suggest that VPS52 is an effector protein that is responsible for the Rab6-dependent secretory cargo trafficking.
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Affiliation(s)
- Yuta Homma
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.
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10
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Clague MJ, Urbé S. Data mining for traffic information. Traffic 2021; 21:162-168. [PMID: 31596015 DOI: 10.1111/tra.12702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/19/2019] [Accepted: 09/19/2019] [Indexed: 12/23/2022]
Abstract
Modern cell biology is now rich with data acquired at the whole genome and proteome level. We can add value to this data through integration and application of specialist knowledge. To illustrate, we will focus on the SNARE and RAB proteins; key regulators of intracellular fusion specificity and organelle identity. We examine published mass spectrometry data to gain an estimate of protein copy number and organelle distribution in HeLa cells for each family member. We also survey recent global CRISPR/Cas9 screens for essential genes from these families. We highlight instances of co-essentiality with other genes across a large panel of cell lines that allows for the identification of functionally coherent clusters. Examples of such correlations include RAB10 with the SNARE protein Syntaxin4 (STX4) and RAB7/RAB21 with the WASH and the CCC (COMMD/CCDC22/CCDC93) complexes, both of which are linked to endosomal recycling pathways.
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Affiliation(s)
- Michael J Clague
- Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Sylvie Urbé
- Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
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11
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Pinar M, Peñalva MA. The fungal RABOME: RAB GTPases acting in the endocytic and exocytic pathways of Aspergillus nidulans (with excursions to other filamentous fungi). Mol Microbiol 2021; 116:53-70. [PMID: 33724562 DOI: 10.1111/mmi.14716] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/04/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022]
Abstract
RAB GTPases are major determinants of membrane identity that have been exploited as highly specific reporters to study intracellular traffic in vivo. A score of fungal papers have considered individual RABs, but systematic, integrated studies on the localization and physiological role of these regulators and their effectors have been performed only with Aspergillus nidulans. These studies have influenced the intracellular trafficking field beyond fungal specialists, leading to findings such as the maturation of trans-Golgi (TGN) cisternae into post-Golgi RAB11 secretory vesicles, the concept that these RAB11 secretory carriers are loaded with three molecular nanomotors, the understanding of the role of endocytic recycling mediated by RAB6 and RAB11 in determining the hyphal mode of life, the discovery that early endosome maturation and the ESCRT pathway are essential, the identification of specific adaptors of dynein-dynactin to RAB5 endosomes, the exquisite dependence that autophagy displays on RAB1 activity, the role of TRAPPII as a GEF for RAB11, or the conclusion that the RAB1-to-RAB11 transition is not mediated by TRAPP maturation. A remarkable finding was that the A. nidulans Spitzenkörper contains four RABs: RAB11, Sec4, RAB6, and RAB1. How these RABs cooperate during exocytosis represents an as yet outstanding question.
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Affiliation(s)
- Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
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12
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Ibuchi K, Fukaya M, Shinohara T, Hara Y, Shiroshima T, Sugawara T, Sakagami H. The Vps52 subunit of the GARP and EARP complexes is a novel Arf6-interacting protein that negatively regulates neurite outgrowth of hippocampal neurons. Brain Res 2020; 1745:146905. [PMID: 32473257 DOI: 10.1016/j.brainres.2020.146905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/18/2020] [Accepted: 05/24/2020] [Indexed: 01/05/2023]
Abstract
ADP ribosylation factor 6 (Arf6) is a small GTP-binding protein implicated in neuronal morphogenesis through endosomal trafficking and actin remodeling. In this study, we identified Vps52, a core subunit of the Golgi-associated retrograde protein (GARP) and endosome-associated recycling protein (EARP) complexes, as a novel Arf6-binding protein by yeast two-hybrid screening. Vps52 interacted specifically with GTP-bound Arf6 among the Arf family. Immunohistochemical analyses of hippocampal pyramidal cells revealed that fine punctate immunolabeling for Vps52 was distributed throughout neuronal compartments, most densely in the cell body and dendritic shafts, and was largely associated with trans-Golgi network and vesicular endomembranes. In cultured hippocampal neurons, knockdown of Vps52 increased total length of axons and dendrites; these phenotypes were completely restored by co-expression of shRNA-resistant full-length Vps52. However, co-expression of a Vps52 mutant lacking the ability to interact with Arf6 restored only the Vps52-knockdown phenotype of the dendritic length. The present findings suggest that Vps52 is a novel Arf6-interacting protein that regulates neurite outgrowth in hippocampal neurons.
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Affiliation(s)
- Kanta Ibuchi
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Tetsuro Shinohara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Yoshinobu Hara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Tomoko Shiroshima
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Takeyuki Sugawara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan.
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13
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Eisemann TJ, Allen F, Lau K, Shimamura GR, Jeffrey PD, Hughson FM. The Sec1/Munc18 protein Vps45 holds the Qa-SNARE Tlg2 in an open conformation. eLife 2020; 9:e60724. [PMID: 32804076 PMCID: PMC7470827 DOI: 10.7554/elife.60724] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 08/15/2020] [Indexed: 01/17/2023] Open
Abstract
Fusion of intracellular trafficking vesicles is mediated by the assembly of SNARE proteins into membrane-bridging complexes. SNARE-mediated membrane fusion requires Sec1/Munc18-family (SM) proteins, SNARE chaperones that can function as templates to catalyze SNARE complex assembly. Paradoxically, the SM protein Munc18-1 traps the Qa-SNARE protein syntaxin-1 in an autoinhibited closed conformation. Here we present the structure of a second SM-Qa-SNARE complex, Vps45-Tlg2. Strikingly, Vps45 holds Tlg2 in an open conformation, with its SNARE motif disengaged from its Habc domain and its linker region unfolded. The domain 3a helical hairpin of Vps45 is unfurled, exposing the presumptive R-SNARE binding site to allow template complex formation. Although Tlg2 has a pronounced tendency to form homo-tetramers, Vps45 can rescue Tlg2 tetramers into stoichiometric Vps45-Tlg2 complexes. Our findings demonstrate that SM proteins can engage Qa-SNAREs using at least two different modes, one in which the SNARE is closed and one in which it is open.
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Affiliation(s)
- Travis J Eisemann
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Frederick Allen
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Kelly Lau
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | | | - Philip D Jeffrey
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
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14
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An optogenetic system to control membrane phospholipid asymmetry through flippase activation in budding yeast. Sci Rep 2020; 10:12474. [PMID: 32719316 PMCID: PMC7385178 DOI: 10.1038/s41598-020-69459-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 07/08/2020] [Indexed: 02/06/2023] Open
Abstract
Lipid asymmetry in biological membranes is essential for various cell functions, such as cell polarity, cytokinesis, and apoptosis. P4-ATPases (flippases) are involved in the generation of such asymmetry. In Saccharomyces cerevisiae, the protein kinases Fpk1p/Fpk2p activate the P4-ATPases Dnf1p/Dnf2p by phosphorylation. Previously, we have shown that a blue-light-dependent protein kinase, phototropin from Chlamydomonas reinhardtii (CrPHOT), complements defects in an fpk1Δ fpk2Δ mutant. Herein, we investigated whether CrPHOT optically regulates P4-ATPase activity. First, we demonstrated that the translocation of NBD-labelled phospholipids to the cytoplasmic leaflet via P4-ATPases was promoted by blue-light irradiation in fpk1Δ fpk2Δ cells with CrPHOT. In addition, blue light completely suppressed the defects in membrane functions (such as endocytic recycling, actin depolarization, and apical-isotropic growth switching) caused by fpk1Δ fpk2Δ mutations. All responses required the kinase activity of CrPHOT. Hence, these results indicate the utility of CrPHOT as a powerful and first tool for optogenetic manipulation of P4-ATPase activity.
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15
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Xu Y, Hu D, Hou X, Shen J, Liu J, Cen X, Fu J, Li X, Hu H, Xiong L. OsTMF attenuates cold tolerance by affecting cell wall properties in rice. THE NEW PHYTOLOGIST 2020; 227:498-512. [PMID: 32176820 DOI: 10.1111/nph.16549] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 03/04/2020] [Indexed: 05/15/2023]
Abstract
Plant cell wall composition and structure can be modified as plants adapt to environmental stresses; however, the underlying regulatory mechanisms remain elusive. Here, we report that OsTMF, a homologue of the human TATA modulatory factor (TMF) in rice (Oryza sativa) and highly conserved in plants, negatively regulates cold tolerance through modification of cell wall properties. Cold stress increased the expression of OsTMF and accumulation of OsTMF in the nucleus, where OsTMF acts as a transcription activator and modulates the expression of genes involved in pectin degradation (OsBURP16), cellulose biosynthesis (OsCesA4 and OsCesA9), and cell wall structural maintenance (genes encoding proline-rich proteins and peroxidases). OsTMF directly activated the expression of OsBURP16, OsCesA4, and OsCesA9 through binding to the TATA cis-elements in their promoters. Under cold stress conditions, OsTMF negatively regulated pectin content and peroxidase activity and positively regulated cellulose content, causing corresponding alterations to cell wall properties, all of which collectively contribute to the negative effect of OsTMF on cold tolerance. Our findings unravel a previously unreported molecular mechanism of a conserved plant TMF protein in the regulation of cell wall changes under cold stress.
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Affiliation(s)
- Yan Xu
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Biofuels, Qingdao Engineering Research Center of Biomass Resources and Environment, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Dan Hu
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Xin Hou
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Jianqiang Shen
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Juhong Liu
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiang Cen
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Jie Fu
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Xianghua Li
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Honghong Hu
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
| | - Lizhong Xiong
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China
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16
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Best JT, Xu P, McGuire JG, Leahy SN, Graham TR. Yeast synaptobrevin, Snc1, engages distinct routes of postendocytic recycling mediated by a sorting nexin, Rcy1-COPI, and retromer. Mol Biol Cell 2020; 31:944-962. [PMID: 32074001 PMCID: PMC7185969 DOI: 10.1091/mbc.e19-05-0290] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 01/31/2020] [Accepted: 02/10/2020] [Indexed: 12/12/2022] Open
Abstract
The budding yeast v-SNARE, Snc1, mediates fusion of exocytic vesicles to the plasma membrane (PM) and is subsequently recycled back to the Golgi. Postendocytic recycling of Snc1 requires a phospholipid flippase (Drs2-Cdc50), an F-box protein (Rcy1), a sorting nexin (Snx4-Atg20), and the COPI coat complex. A portion of the endocytic tracer FM4-64 is also recycled back to the PM after internalization. However, the relationship between Snx4, Drs2, Rcy1, and COPI in recycling Snc1 or FM4-64 is unclear. Here we show that rcy1∆ and drs2∆ single mutants, or a COPI mutant deficient in ubiquitin binding, display a defect in recycling FM4-64 while snx4∆ cells recycle FM4-64 normally. The addition of latrunculin A to acutely inhibit endocytosis shows that rcy1∆ and snx4∆ single mutants retain the ability to recycle Snc1, but a snx4∆rcy1∆ mutant substantially blocks export. Additional deletion of a retromer subunit completely eliminates recycling of Snc1 in the triple mutant (snx4∆rcy1∆vps35∆). A minor role for retromer in Snc1 recycling can also be observed in single and double mutants harboring vps35∆. These data support the existence of three distinct and parallel recycling pathways mediated by Drs2/Rcy1/COPI, Snx4-Atg20, and retromer that retrieve an exocytic v-SNARE from the endocytic pathway to the Golgi.
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Affiliation(s)
- Jordan T. Best
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Peng Xu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Jack G. McGuire
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Shannon N. Leahy
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Todd R. Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
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17
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Ishida M, Bonifacino JS. ARFRP1 functions upstream of ARL1 and ARL5 to coordinate recruitment of distinct tethering factors to the trans-Golgi network. J Cell Biol 2019; 218:3681-3696. [PMID: 31575603 PMCID: PMC6829661 DOI: 10.1083/jcb.201905097] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/09/2019] [Accepted: 08/27/2019] [Indexed: 12/22/2022] Open
Abstract
SNARE-mediated fusion of endosome-derived transport carriers with the trans-Golgi network (TGN) depends on the concerted action of two types of tethering factors: long coiled-coil tethers of the golgin family, and the heterotetrameric complex GARP. Whereas the golgins mediate long-distance capture of the carriers, GARP promotes assembly of the SNAREs. It remains to be determined, however, how the functions of these tethering factors are coordinated. Herein we report that the ARF-like (ARL) GTPase ARFRP1 functions upstream of two other ARL GTPases, ARL1 and ARL5, which in turn recruit golgins and GARP, respectively, to the TGN. We also show that this mechanism is essential for the delivery of retrograde cargos to the TGN. Our findings thus demonstrate that ARFRP1 is a master regulator of retrograde-carrier tethering to the TGN. The coordinated recruitment of distinct tethering factors by a bifurcated GTPase cascade may be paradigmatic of other vesicular fusion events within the cell.
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Affiliation(s)
- Morié Ishida
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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18
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Ma M, Burd CG. Retrograde trafficking and plasma membrane recycling pathways of the budding yeast Saccharomyces cerevisiae. Traffic 2019; 21:45-59. [PMID: 31471931 DOI: 10.1111/tra.12693] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 02/06/2023]
Abstract
The endosomal system functions as a network of protein and lipid sorting stations that receives molecules from endocytic and secretory pathways and directs them to the lysosome for degradation, or exports them from the endosome via retrograde trafficking or plasma membrane recycling pathways. Retrograde trafficking pathways describe endosome-to-Golgi transport while plasma membrane recycling pathways describe trafficking routes that return endocytosed molecules to the plasma membrane. These pathways are crucial for lysosome biogenesis, nutrient acquisition and homeostasis and for the physiological functions of many types of specialized cells. Retrograde and recycling sorting machineries of eukaryotic cells were identified chiefly through genetic screens using the budding yeast Saccharomyces cerevisiae system and discovered to be highly conserved in structures and functions. In this review, we discuss advances regarding retrograde trafficking and recycling pathways, including new discoveries that challenge existing ideas about the organization of the endosomal system, as well as how these pathways intersect with cellular homeostasis pathways.
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Affiliation(s)
- Mengxiao Ma
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut
| | - Christopher G Burd
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut
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19
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Tojima T, Suda Y, Ishii M, Kurokawa K, Nakano A. Spatiotemporal dissection of the trans-Golgi network in budding yeast. J Cell Sci 2019; 132:jcs.231159. [PMID: 31289195 PMCID: PMC6703704 DOI: 10.1242/jcs.231159] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/01/2019] [Indexed: 12/27/2022] Open
Abstract
The trans-Golgi network (TGN) acts as a sorting hub for membrane traffic. It receives newly synthesized and recycled proteins, and sorts and delivers them to specific targets such as the plasma membrane, endosomes and lysosomes/vacuoles. Accumulating evidence suggests that the TGN is generated from the trans-most cisterna of the Golgi by maturation, but the detailed transition processes remain obscure. Here, we examine spatiotemporal assembly dynamics of various Golgi/TGN-resident proteins in budding yeast by high-speed and high-resolution spinning-disk confocal microscopy. The Golgi–TGN transition gradually proceeds via at least three successive stages: the ‘Golgi stage’ where glycosylation occurs; the ‘early TGN stage’, which receives retrograde traffic; and the ‘late TGN stage’, where transport carriers are produced. During the stage transition periods, earlier and later markers are often compartmentalized within a cisterna. Furthermore, for the late TGN stage, various types of coat/adaptor proteins exhibit distinct assembly patterns. Taken together, our findings characterize the identity of the TGN as a membrane compartment that is structurally and functionally distinguishable from the Golgi. This article has an associated First Person interview with the first author of the paper. Highlighted Article: The TGN displays two sub-stages of maturation: ‘early TGN’, when retrograde traffic is received, and ‘late TGN’, when transport carriers are produced. At the late TGN, various coat/adaptor proteins exhibit distinct assembly dynamics.
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Affiliation(s)
- Takuro Tojima
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Yasuyuki Suda
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan.,Laboratory of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Midori Ishii
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
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20
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Anderson NS, Barlowe C. Conserved juxtamembrane domains in the yeast golgin Coy1 drive assembly of a megadalton-sized complex and mediate binding to tethering and SNARE proteins. J Biol Chem 2019; 294:9690-9705. [PMID: 31073031 DOI: 10.1074/jbc.ra119.008107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/26/2019] [Indexed: 12/13/2022] Open
Abstract
The architecture and organization of the Golgi complex depend on a family of coiled-coil proteins called golgins. Golgins are thought to form extended homodimers that are C-terminally anchored to Golgi membranes, whereas their N termini extend into the cytoplasm to initiate vesicle capture. Previously, we reported that the Saccharomyces cerevisiae golgin Coy1 contributes to intra-Golgi retrograde transport and binds to the conserved oligomeric Golgi (COG) complex and multiple retrograde Golgi Q-SNAREs (where SNARE is soluble NSF-attachment protein receptor). Here, using various engineered yeast strains, membrane protein extraction and fractionation methods, and in vitro binding assays, we mapped the Coy1 regions responsible for these activities. We also report that Coy1 assembles into a megadalton-size complex and that assembly of this complex depends on the most C-terminal coiled-coil and a conserved region between this coiled-coil and the transmembrane domain of Coy1. We found that this conserved region is necessary and sufficient for binding the SNARE protein Sed5 and the COG complex. Mutagenesis of conserved arginine residues within the C-terminal coiled-coil disrupted oligomerization, binding, and function of Coy1. Our findings indicate that the stable incorporation of Coy1 into a higher-order oligomer is required for its interactions and role in maintaining Golgi homeostasis. We propose that Coy1 assembles into a docking platform that directs COG-bound vesicles toward cognate SNAREs on the Golgi membrane.
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Affiliation(s)
- Nadine S Anderson
- From the Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755
| | - Charles Barlowe
- From the Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755
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21
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Gershlick DC, Ishida M, Jones JR, Bellomo A, Bonifacino JS, Everman DB. A neurodevelopmental disorder caused by mutations in the VPS51 subunit of the GARP and EARP complexes. Hum Mol Genet 2019; 28:1548-1560. [PMID: 30624672 PMCID: PMC6489419 DOI: 10.1093/hmg/ddy423] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 11/27/2018] [Accepted: 12/02/2018] [Indexed: 11/12/2022] Open
Abstract
Golgi-associated retrograde protein (GARP) and endosome-associated recycling protein (EARP) are related heterotetrameric complexes that associate with the cytosolic face of the trans-Golgi network and recycling endosomes, respectively. At these locations, GARP and EARP function to promote the fusion of endosome-derived transport carriers with their corresponding compartments. GARP and EARP share three subunits, VPS51, VPS52 and VPS53, and each has an additional complex-specific subunit, VPS54 or VPS50, respectively. The role of these complexes in human physiology, however, remains poorly understood. By exome sequencing, we have identified compound heterozygous mutations in the gene encoding the shared GARP/EARP subunit VPS51 in a 6-year-old patient with severe global developmental delay, microcephaly, hypotonia, epilepsy, cortical vision impairment, pontocerebellar abnormalities, failure to thrive, liver dysfunction, lower extremity edema and dysmorphic features. The mutation in one allele causes a frameshift that produces a longer but highly unstable protein that is degraded by the proteasome. In contrast, the other mutant allele produces a protein with a single amino acid substitution that is stable but assembles less efficiently with the other GARP/EARP subunits. Consequently, skin fibroblasts from the patient have reduced levels of fully assembled GARP and EARP complexes. Likely because of this deficiency, the patient's fibroblasts display altered distribution of the cation-independent mannose 6-phosphate receptor, which normally sorts acid hydrolases to lysosomes. Furthermore, a fraction of the patient's fibroblasts exhibits swelling of lysosomes. These findings thus identify a novel genetic locus for a neurodevelopmental disorder and highlight the critical importance of GARP/EARP function in cellular and organismal physiology.
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Affiliation(s)
- David C Gershlick
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Morié Ishida
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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22
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Chen YT, Wang IH, Wang YH, Chiu WY, Hu JH, Chen WH, Lee FJS. Action of Arl1 GTPase and golgin Imh1 in Ypt6-independent retrograde transport from endosomes to the trans-Golgi network. Mol Biol Cell 2019; 30:1008-1019. [PMID: 30726160 PMCID: PMC6589904 DOI: 10.1091/mbc.e18-09-0579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Arf and Rab/Ypt GTPases coordinately regulate membrane traffic and organelle structure by regulating vesicle formation and fusion. Ample evidence has indicated that proteins in these two families may function in parallel or complementarily; however, the manner in which Arf and Rab/Ypt proteins perform interchangeable functions remains unclear. In this study, we report that a Golgi-localized Arf, Arl1, could suppress Ypt6 dysfunction via its effector golgin, Imh1, but not via the lipid flippase Drs2. Ypt6 is critical for the retrograde transport of vesicles from endosomes to the trans-Golgi network (TGN), and its mutation leads to severe protein mislocalization and growth defects. We first overexpress the components of the Arl3-Syt1-Arl1-Imh1 cascade and show that only Arl1 and Imh1 can restore endosome-to-TGN trafficking in ypt6-deleted cells. Interestingly, increased abundance of Arl1 or Imh1 restores localization of the tethering factor Golgi associated retrograde–protein (GARP) complex to the TGN in the absence of Ypt6. We further show that the N-terminal domain of Imh1 is critical for restoring GARP localization and endosome-to-TGN transport in ypt6-deleted cells. Together, our results reveal the mechanism by which Arl1-Imh1 facilitates the recruitment of GARP to the TGN and compensates for the endosome-to-TGN trafficking defects in dysfunctional Ypt6 conditions.
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Affiliation(s)
- Yan-Ting Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - I-Hao Wang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yi-Hsun Wang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Wan-Yun Chiu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Jen-Hao Hu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Wen-Hui Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Fang-Jen S Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan.,Department of Medical Research, National Taiwan University Hospital, Taipei 100, Taiwan.,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
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23
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He M, Lan M, Zhang B, Zhou Y, Wang Y, Zhu L, Yuan M, Fu Y. Rab-H1b is essential for trafficking of cellulose synthase and for hypocotyl growth in Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:1051-1069. [PMID: 29975455 DOI: 10.1111/jipb.12694] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 07/03/2018] [Indexed: 05/26/2023]
Abstract
Cell-wall deposition of cellulose microfibrils is essential for plant growth and development. In plant cells, cellulose synthesis is accomplished by cellulose synthase complexes located in the plasma membrane. Trafficking of the complex between endomembrane compartments and the plasma membrane is vital for cellulose biosynthesis; however, the mechanism for this process is not well understood. We here report that, in Arabidopsis thaliana, Rab-H1b, a Golgi-localized small GTPase, participates in the trafficking of CELLULOSE SYNTHASE 6 (CESA6) to the plasma membrane. Loss of Rab-H1b function resulted in altered distribution and motility of CESA6 in the plasma membrane and reduced cellulose content. Seedlings with this defect exhibited short, fragile etiolated hypocotyls. Exocytosis of CESA6 was impaired in rab-h1b cells, and endocytosis in mutant cells was significantly reduced as well. We further observed accumulation of vesicles around an abnormal Golgi apparatus having an increased number of cisternae in rab-h1b cells, suggesting a defect in cisternal homeostasis caused by Rab-H1b loss function. Our findings link Rab GTPases to cellulose biosynthesis, during hypocotyl growth, and suggest Rab-H1b is crucial for modulating the trafficking of cellulose synthase complexes between endomembrane compartments and the plasma membrane and for maintaining Golgi organization and morphology.
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Affiliation(s)
- Ming He
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Miao Lan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Baocai Zhang
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences, Beijing 100101, China
| | - Youqun Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Lei Zhu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ming Yuan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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Ayala CI, Kim J, Neufeld TP. Rab6 promotes insulin receptor and cathepsin trafficking to regulate autophagy induction and activity in Drosophila. J Cell Sci 2018; 131:jcs.216127. [PMID: 30111579 DOI: 10.1242/jcs.216127] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/02/2018] [Indexed: 01/07/2023] Open
Abstract
The self-degradative process of autophagy is important for energy homeostasis and cytoplasmic renewal. This lysosome-mediated pathway is negatively regulated by the target of rapamycin kinase (TOR) under basal conditions, and requires the vesicle trafficking machinery regulated by Rab GTPases. However, the interactions between autophagy, TOR and Rab proteins remain incompletely understood in vivo Here, we identify Rab6 as a critical regulator of the balance between TOR signaling and autolysosome function. Loss of Rab6 causes an accumulation of enlarged autophagic vesicles resulting in part from a failure to deliver lysosomal hydrolases, rendering autolysosomes with a reduced degradative capacity and impaired turnover. Additionally, Rab6-deficient cells are reduced in size and display defective insulin-TOR signaling as a result of mis-sorting and internalization of the insulin receptor. Our findings suggest that Rab6 acts to maintain the reciprocal regulation between autophagy and TOR activity during distinct nutrient states, thereby balancing autophagosome production and turnover to avoid autophagic stress.
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Affiliation(s)
- Carlos I Ayala
- Department of Genetics, Cell Biology and Development, 6-160 Jackson Hall, 321 Church St. SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jung Kim
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology and Development, 6-160 Jackson Hall, 321 Church St. SE, University of Minnesota, Minneapolis, MN 55455, USA
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25
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Makaraci P, Delgado Cruz M, McDermott H, Nguyen V, Highfill C, Kim K. Yeast dynamin and Ypt6 function in parallel for the endosome-to-Golgi retrieval of Snc1. Cell Biol Int 2018; 43:1137-1151. [PMID: 30080296 DOI: 10.1002/cbin.11042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Protein recycling is an important cellular process required for cell homeostasis. Results from prior studies have shown that vacuolar sorting protein-1 (Vps1), a dynamin homolog in yeast, is implicated in protein recycling from the endosome to the trans-Golgi Network (TGN). However, the function of Vps1 in relation to Ypt6, a master GTPase in the recycling pathway, remains unknown. The present study reveals that Vps1 physically interacts with Ypt6 if at least one of them is full-length. We found that overexpression of full-length Vps1, but not GTP hydrolysis-defective Vps1 mutants, is sufficient to rescue abnormal phenotypes of Snc1 distribution provoked by the loss of Ypt6, and vice versa. This suggests that Vps1 and Ypt6 function in parallel pathways instead of in a sequential pathway and that GTP binding/hydrolysis of Vps1 is required for proper traffic of Snc1 toward the TGN. Additionally, we identified two novel Vps1-binding partners, Vti1 and Snc2, which function for the endosome-derived vesicle fusion at the TGN. Taken together, the present study demonstrates that Vps1 plays a role in later stages of the endosome-to-TGN traffic.
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Affiliation(s)
- Pelin Makaraci
- Department of Biology, Missouri State University, 901S National, Springfield, MO, 65807, USA
| | | | - Hyoeun McDermott
- Department of Biology, Missouri State University, 901S National, Springfield, MO, 65807, USA
| | | | - Chad Highfill
- Department of Biology, Missouri State University, 901S National, Springfield, MO, 65807, USA.,Genetics Program, North Carolina State University, Raleigh, NC, 27695, USA
| | - Kyoungtae Kim
- Department of Biology, Missouri State University, 901S National, Springfield, MO, 65807, USA
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Hernández-González M, Bravo-Plaza I, Pinar M, de los Ríos V, Arst HN, Peñalva MA. Endocytic recycling via the TGN underlies the polarized hyphal mode of life. PLoS Genet 2018; 14:e1007291. [PMID: 29608571 PMCID: PMC5880334 DOI: 10.1371/journal.pgen.1007291] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/06/2018] [Indexed: 12/13/2022] Open
Abstract
Intracellular traffic in Aspergillus nidulans hyphae must cope with the challenges that the high rates of apical extension (1μm/min) and the long intracellular distances (>100 μm) impose. Understanding the ways in which the hyphal tip cell coordinates traffic to meet these challenges is of basic importance, but is also of considerable applied interest, as fungal invasiveness of animals and plants depends critically upon maintaining these high rates of growth. Rapid apical extension requires localization of cell-wall-modifying enzymes to hyphal tips. By combining genetic blocks in different trafficking steps with multidimensional epifluorescence microscopy and quantitative image analyses we demonstrate that polarization of the essential chitin-synthase ChsB occurs by indirect endocytic recycling, involving delivery/exocytosis to apices followed by internalization by the sub-apical endocytic collar of actin patches and subsequent trafficking to TGN cisternae, where it accumulates for ~1 min before being re-delivered to the apex by a RAB11/TRAPPII-dependent pathway. Accordingly, ChsB is stranded at the TGN by Sec7 inactivation but re-polarizes to the apical dome if the block is bypassed by a mutation in geaAgea1 that restores growth in the absence of Sec7. That polarization is independent of RAB5, that ChsB predominates at apex-proximal cisternae, and that upon dynein impairment ChsB is stalled at the tips in an aggregated endosome indicate that endocytosed ChsB traffics to the TGN via sorting endosomes functionally located upstream of the RAB5 domain and that this step requires dynein-mediated basipetal transport. It also requires RAB6 and its effector GARP (Vps51/Vps52/Vps53/Vps54), whose composition we determined by MS/MS following affinity chromatography purification. Ablation of any GARP component diverts ChsB to vacuoles and impairs growth and morphology markedly, emphasizing the important physiological role played by this pathway that, we propose, is central to the hyphal mode of growth. Filamentous fungi form long tubular cells, called hyphae, which grow rapidly by apical extension, enabling these sessile organisms to explore substrates and facilitating tissue invasion in the case of pathogenic species. Because the shape of the hyphae is determined by an external cell wall, hyphal growth requires that cell-wall sculpting enzymes polarize to the tips. Endocytosis is essential for hyphal growth, and it was suspected that this results from its participation in a recycling pathway that takes up cell-wall enzymes from the plasma membrane and re-delivers them to the apex. Here we track the trafficking of a chitin synthase (a cell-wall modifying enzyme) to demonstrate that it is polarized by endocytic recycling. This chitin synthase is delivered by exocytosis to the apex, but diffuses away until being captured by a subapical collar of actin patches (sites of endocytosis) from where it reaches a sorting endosome before undergoing transport to the nearest trans-Golgi cisternae and incorporating into secretory vesicles that re-deliver the enzyme to the apex. Because impairing transit across this pathway compromises apical extension markedly and results in severe morphological defects, the pathway could be manipulated to prevent fungal pathogenicity of plants and humans, an enormous burden on human welfare.
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Affiliation(s)
- Miguel Hernández-González
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Ignacio Bravo-Plaza
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Mario Pinar
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Vivian de los Ríos
- Proteomics Facility, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Herbert N. Arst
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, United Kingdom
| | - Miguel A. Peñalva
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
- * E-mail:
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27
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Hovsepian J, Albanèse V, Becuwe M, Ivashov V, Teis D, Léon S. The yeast arrestin-related protein Bul1 is a novel actor of glucose-induced endocytosis. Mol Biol Cell 2018. [PMID: 29514933 PMCID: PMC5921569 DOI: 10.1091/mbc.e17-07-0466] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Yeast cells have a remarkable ability to adapt to nutritional changes in their environment. During adaptation, nutrient-signaling pathways drive the selective endocytosis of nutrient transporters present at the cell surface. A current challenge is to understand the mechanistic basis of this regulation. Transporter endocytosis is triggered by their ubiquitylation, which involves the ubiquitin ligase Rsp5 and its adaptors of the arrestin-related family (ART). This step is highly regulated by nutrient availability. For instance, the monocarboxylate transporter Jen1 is ubiquitylated, endocytosed, and degraded upon exposure to glucose. The ART protein Rod1 is required for this overall process; yet Rod1 rather controls Jen1 trafficking later in the endocytic pathway and is almost dispensable for Jen1 internalization. Thus, how glucose triggers Jen1 internalization remains unclear. We report that another ART named Bul1, but not its paralogue Bul2, contributes to Jen1 internalization. Bul1 responds to glucose availability, and preferentially acts at the plasma membrane for Jen1 internalization. Thus, multiple ARTs can act sequentially along the endocytic pathway to control transporter homeostasis. Moreover, Bul1 is in charge of Jen1 endocytosis after cycloheximide treatment, suggesting that the functional redundancy of ARTs may be explained by their ability to interact with multiple cargoes in various conditions.
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Affiliation(s)
- Junie Hovsepian
- Institut Jacques Monod, UMR 7592 Centre National de la Recherche Scientifique/Université Paris-Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Véronique Albanèse
- Institut Jacques Monod, UMR 7592 Centre National de la Recherche Scientifique/Université Paris-Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Michel Becuwe
- Institut Jacques Monod, UMR 7592 Centre National de la Recherche Scientifique/Université Paris-Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Vasyl Ivashov
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - David Teis
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Sébastien Léon
- Institut Jacques Monod, UMR 7592 Centre National de la Recherche Scientifique/Université Paris-Diderot, Sorbonne Paris Cité, 75205 Paris, France
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Molecular Insights into the Roles of Rab Proteins in Intracellular Dynamics and Neurodegenerative Diseases. Neuromolecular Med 2018; 20:18-36. [PMID: 29423895 DOI: 10.1007/s12017-018-8479-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/27/2018] [Indexed: 02/01/2023]
Abstract
In eukaryotes, the cellular functions are segregated to membrane-bound organelles. This inherently requires sorting of metabolites to membrane-limited locations. Sorting the metabolites from ribosomes to various organelles along the intracellular trafficking pathways involves several integral cellular processes, including an energy-dependent step, in which the sorting of metabolites between organelles is catalyzed by membrane-anchoring protein Rab-GTPases (Rab). They contribute to relaying the switching of the secretory proteins between hydrophobic and hydrophilic environments. The intracellular trafficking routes include exocytic and endocytic pathways. In these pathways, numerous Rab-GTPases are participating in discrete shuttling of cargoes. Long-distance trafficking of cargoes is essential for neuronal functions, and Rabs are critical for these functions, including the transport of membranes and essential proteins for the development of axons and neurites. Rabs are also the key players in exocytosis of neurotransmitters and recycling of neurotransmitter receptors. Thus, Rabs are critical for maintaining neuronal communication, as well as for normal cellular physiology. Therefore, cellular defects of Rab components involved in neural functions, which severely affect normal brain functions, can produce neurological complications, including several neurodegenerative diseases. In this review, we provide a comprehensive overview of the current understanding of the molecular signaling pathways of Rab proteins and the impact of their defects on different neurodegenerative diseases. The insights gathered into the dynamics of Rabs that are described in this review provide new avenues for developing effective treatments for neurodegenerative diseases-associated with Rab defects.
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29
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Makaraci P, Kim K. trans-Golgi network-bound cargo traffic. Eur J Cell Biol 2018; 97:137-149. [PMID: 29398202 DOI: 10.1016/j.ejcb.2018.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/15/2017] [Accepted: 01/16/2018] [Indexed: 12/19/2022] Open
Abstract
Cargo following the retrograde trafficking are sorted at endosomes to be targeted the trans-Golgi network (TGN), a central receiving organelle. Though molecular requirements and their interaction networks have been somewhat established, the complete understanding of the intricate nature of their action mechanisms in every step of the retrograde traffic pathway remains unachieved. This review focuses on elucidating known functions of key regulators, including scission factors at the endosome and tethering/fusion mediators at the receiving dock, TGN, as well as a diverse range of cargo.
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Affiliation(s)
- Pelin Makaraci
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA
| | - Kyoungtae Kim
- Department of Biology, Missouri State University, 901 S National Ave., Springfield, MO 65807, USA.
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30
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Suda Y, Kurokawa K, Nakano A. Regulation of ER-Golgi Transport Dynamics by GTPases in Budding Yeast. Front Cell Dev Biol 2018; 5:122. [PMID: 29473037 PMCID: PMC5810278 DOI: 10.3389/fcell.2017.00122] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/28/2017] [Indexed: 01/21/2023] Open
Abstract
A large number of proteins are synthesized de novo in the endoplasmic reticulum (ER). They are transported through the Golgi apparatus and then delivered to their proper destinations. The ER and the Golgi play a central role in protein processing and sorting and show dynamic features in their forms. Ras super family small GTPases mediate the protein transport through and between these organelles. The ER-localized GTPase, Sar1, facilitates the formation of COPII transport carriers at the ER exit sites (ERES) on the ER for the transport of cargo proteins from the ER to the Golgi. The Golgi-localized GTPase, Arf1, controls intra-Golgi, and Golgi-to-ER transport of cargo proteins by the formation of COPI carriers. Rab GTPases localized at the Golgi, which are responsible for fusion of membranes, are thought to establish the identities of compartments. Recent evidence suggests that these small GTPases regulate not only discrete sites for generation/fusion of transport carriers, but also membrane dynamics of the organelles where they locate to ensure the integrity of transport. Here we summarize the current understandings about the membrane traffic between these organelles and highlight the cutting-edge advances from super-resolution live imaging of budding yeast, Saccharomyces cerevisiae.
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Affiliation(s)
- Yasuyuki Suda
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan.,Laboratory of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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31
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 286] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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32
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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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33
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Pantazopoulou A. The Golgi apparatus: insights from filamentous fungi. Mycologia 2017; 108:603-22. [DOI: 10.3852/15-309] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/01/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Areti Pantazopoulou
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
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34
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Yang S, Rosenwald AG. Autophagy in Saccharomyces cerevisiae requires the monomeric GTP-binding proteins, Arl1 and Ypt6. Autophagy 2016; 12:1721-1737. [PMID: 27462928 PMCID: PMC5079543 DOI: 10.1080/15548627.2016.1196316] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Macroautophagy/autophagy is a cellular degradation process that sequesters organelles or proteins into a double-membrane structure called the phagophore; this transient compartment matures into an autophagosome, which then fuses with the lysosome or vacuole to allow hydrolysis of the cargo. Factors that control membrane traffic are also essential for each step of autophagy. Here we demonstrate that 2 monomeric GTP-binding proteins in Saccharomyces cerevisiae, Arl1 and Ypt6, which belong to the Arf/Arl/Sar protein family and the Rab family, respectively, and control endosome-trans-Golgi traffic, are also necessary for starvation-induced autophagy under high temperature stress. Using established autophagy-specific assays we found that cells lacking either ARL1 or YPT6, which exhibit synthetic lethality with one another, were unable to undergo autophagy at an elevated temperature, although autophagy proceeds normally at normal growth temperature; specifically, strains lacking one or the other of these genes are unable to construct the autophagosome because these 2 proteins are required for proper traffic of Atg9 to the phagophore assembly site (PAS) at the restrictive temperature. Using degron technology to construct an inducible arl1Δ ypt6Δ double mutant, we demonstrated that cells lacking both genes show defects in starvation-inducted autophagy at the permissive temperature. We also found Arl1 and Ypt6 participate in autophagy by targeting the Golgi-associated retrograde protein (GARP) complex to the PAS to regulate the anterograde trafficking of Atg9. Our data show that these 2 membrane traffic regulators have novel roles in autophagy.
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Affiliation(s)
- Shu Yang
- a Department of Biology , Georgetown University , Washington DC , USA
| | - Anne G Rosenwald
- a Department of Biology , Georgetown University , Washington DC , USA
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35
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Vukašinović N, Žárský V. Tethering Complexes in the Arabidopsis Endomembrane System. Front Cell Dev Biol 2016; 4:46. [PMID: 27243010 PMCID: PMC4871884 DOI: 10.3389/fcell.2016.00046] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/02/2016] [Indexed: 12/30/2022] Open
Abstract
Targeting of endomembrane transport containers is of the utmost importance for proper land plant growth and development. Given the immobility of plant cells, localized membrane vesicle secretion and recycling are amongst the main processes guiding proper cell, tissue and whole plant morphogenesis. Cell wall biogenesis and modification are dependent on vectorial membrane traffic, not only during normal development, but also in stress responses and in plant defense against pathogens and/or symbiosis. It is surprising how little we know about these processes in plants, from small GTPase regulation to the tethering complexes that act as their effectors. Tethering factors are single proteins or protein complexes mediating first contact between the target membrane and arriving membrane vesicles. In this review we focus on the tethering complexes of the best-studied plant model—Arabidopsis thaliana. Genome-based predictions indicate the presence of all major tethering complexes in plants that are known from a hypothetical last eukaryotic common ancestor (LECA). The evolutionary multiplication of paralogs of plant tethering complex subunits has produced the massively expanded EXO70 family, indicating a subfunctionalization of the terminal exocytosis machinery in land plants. Interpretation of loss of function (LOF) mutant phenotypes has to consider that related, yet clearly functionally-specific complexes often share some common core subunits. It is therefore impossible to conclude with clarity which version of the complex is responsible for the phenotypic deviations observed. Experimental interest in the analysis of plant tethering complexes is growing and we hope to contribute with this review by attracting even more attention to this fascinating field of plant cell biology.
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Affiliation(s)
- Nemanja Vukašinović
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University Prague, Czech Republic
| | - Viktor Žárský
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University Prague, Czech Republic
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36
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Topalidou I, Cattin-Ortolá J, Pappas AL, Cooper K, Merrihew GE, MacCoss MJ, Ailion M. The EARP Complex and Its Interactor EIPR-1 Are Required for Cargo Sorting to Dense-Core Vesicles. PLoS Genet 2016; 12:e1006074. [PMID: 27191843 PMCID: PMC4871572 DOI: 10.1371/journal.pgen.1006074] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/30/2016] [Indexed: 12/15/2022] Open
Abstract
The dense-core vesicle is a secretory organelle that mediates the regulated release of peptide hormones, growth factors, and biogenic amines. Dense-core vesicles originate from the trans-Golgi of neurons and neuroendocrine cells, but it is unclear how this specialized organelle is formed and acquires its specific cargos. To identify proteins that act in dense-core vesicle biogenesis, we performed a forward genetic screen in Caenorhabditis elegans for mutants defective in dense-core vesicle function. We previously reported the identification of two conserved proteins that interact with the small GTPase RAB-2 to control normal dense-core vesicle cargo-sorting. Here we identify several additional conserved factors important for dense-core vesicle cargo sorting: the WD40 domain protein EIPR-1 and the endosome-associated recycling protein (EARP) complex. By assaying behavior and the trafficking of dense-core vesicle cargos, we show that mutants that lack EIPR-1 or EARP have defects in dense-core vesicle cargo-sorting similar to those of mutants in the RAB-2 pathway. Genetic epistasis data indicate that RAB-2, EIPR-1 and EARP function in a common pathway. In addition, using a proteomic approach in rat insulinoma cells, we show that EIPR-1 physically interacts with the EARP complex. Our data suggest that EIPR-1 is a new interactor of the EARP complex and that dense-core vesicle cargo sorting depends on the EARP-dependent trafficking of cargo through an endosomal sorting compartment. Animal cells package and store many important signaling molecules in specialized compartments called dense-core vesicles. Molecules stored in dense-core vesicles include peptide hormones like insulin and small molecule neurotransmitters like dopamine. Defects in the release of these compounds can lead to a wide range of metabolic and mental disorders in humans, including diabetes, depression, and drug addiction. However, it is not well understood how dense-core vesicles are formed in cells and package the appropriate molecules. Here we use a genetic screen in the microscopic worm C. elegans to identify proteins that are important for early steps in the generation of dense-core vesicles, such as packaging the correct molecular cargos in the vesicles. We identify several factors that are conserved between worms and humans and point to a new role for a protein complex that had previously been shown to be important for controlling trafficking in other cellular compartments. The identification of this complex suggests new cellular trafficking events that may be important for the generation of dense-core vesicles.
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Affiliation(s)
- Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Jérôme Cattin-Ortolá
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Andrea L. Pappas
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Kirsten Cooper
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Gennifer E. Merrihew
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Michael J. MacCoss
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Dubuke ML, Munson M. The Secret Life of Tethers: The Role of Tethering Factors in SNARE Complex Regulation. Front Cell Dev Biol 2016; 4:42. [PMID: 27243006 PMCID: PMC4860414 DOI: 10.3389/fcell.2016.00042] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/25/2016] [Indexed: 02/03/2023] Open
Abstract
Trafficking in eukaryotic cells is a tightly regulated process to ensure correct cargo delivery to the proper destination organelle or plasma membrane. In this review, we focus on how the vesicle fusion machinery, the SNARE complex, is regulated by the interplay of the multisubunit tethering complexes (MTC) with the SNAREs and Sec1/Munc18 (SM) proteins. Although these factors are used in different stages of membrane trafficking, e.g., Golgi to plasma membrane transport vs. vacuolar fusion, and in a variety of diverse eukaryotic cell types, many commonalities between their functions are being revealed. We explore the various protein-protein interactions and findings from functional reconstitution studies in order to highlight both their common features and the differences in their modes of regulation. These studies serve as a starting point for mechanistic explorations in other systems.
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Affiliation(s)
- Michelle L Dubuke
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, MA USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, MA USA
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Cheung PYP, Pfeffer SR. Transport Vesicle Tethering at the Trans Golgi Network: Coiled Coil Proteins in Action. Front Cell Dev Biol 2016; 4:18. [PMID: 27014693 PMCID: PMC4791371 DOI: 10.3389/fcell.2016.00018] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 02/29/2016] [Indexed: 12/14/2022] Open
Abstract
The Golgi complex is decorated with so-called Golgin proteins that share a common feature: a large proportion of their amino acid sequences are predicted to form coiled-coil structures. The possible presence of extensive coiled coils implies that these proteins are highly elongated molecules that can extend a significant distance from the Golgi surface. This property would help them to capture or trap inbound transport vesicles and to tether Golgi mini-stacks together. This review will summarize our current understanding of coiled coil tethers that are needed for the receipt of transport vesicles at the trans Golgi network (TGN). How do long tethering proteins actually catch vesicles? Golgi-associated, coiled coil tethers contain numerous binding sites for small GTPases, SNARE proteins, and vesicle coat proteins. How are these interactions coordinated and are any or all of them important for the tethering process? Progress toward understanding these questions and remaining, unresolved mysteries will be discussed.
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Affiliation(s)
- Pak-Yan P Cheung
- Department of Biochemistry, Stanford University School of Medicine Stanford, CA, USA
| | - Suzanne R Pfeffer
- Department of Biochemistry, Stanford University School of Medicine Stanford, CA, USA
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Papanikou E, Day KJ, Austin J, Glick BS. COPI selectively drives maturation of the early Golgi. eLife 2015; 4. [PMID: 26709839 PMCID: PMC4758959 DOI: 10.7554/elife.13232] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 12/27/2015] [Indexed: 12/12/2022] Open
Abstract
COPI coated vesicles carry material between Golgi compartments, but the role of COPI in the secretory pathway has been ambiguous. Previous studies of thermosensitive yeast COPI mutants yielded the surprising conclusion that COPI was dispensable both for the secretion of certain proteins and for Golgi cisternal maturation. To revisit these issues, we optimized the anchor-away method, which allows peripheral membrane proteins such as COPI to be sequestered rapidly by adding rapamycin. Video fluorescence microscopy revealed that COPI inactivation causes an early Golgi protein to remain in place while late Golgi proteins undergo cycles of arrival and departure. These dynamics generate partially functional hybrid Golgi structures that contain both early and late Golgi proteins, explaining how secretion can persist when COPI has been inactivated. Our findings suggest that cisternal maturation involves a COPI-dependent pathway that recycles early Golgi proteins, followed by multiple COPI-independent pathways that recycle late Golgi proteins. DOI:http://dx.doi.org/10.7554/eLife.13232.001 Proteins play many important roles for cells, and these roles often require the proteins to be in particular locations in or around the cells. A set of cell compartments called the Golgi packages certain proteins into bubble-like structures called vesicles to enable the proteins to be used elsewhere in the cell or released to the outside of the cell, in a process called the secretory pathway. The operation of the secretory pathway requires the Golgi compartments to be continually remodeled. Proteins and other materials can be ferried between the compartments of the Golgi by another type of vesicle. These vesicles are coated with a group, or complex, of proteins called COPI, which forms a curved lattice around the vesicles and helps them to capture the materials they will transport. However, it is not clear whether COPI is also involved in remodeling of the Golgi compartments. Papanikou, Day et al. addressed this question using a technique called the “anchor-away method” combined with microscopy to study COPI in yeast cells. The yeast were genetically engineered so that COPI activity was effectively shut down in the presence of a drug called rapamycin. The experiments show that COPI is involved in the early stages of remodeling the Golgi compartments, but not the later stages. This finding supports the emerging view of the Golgi as a self-organizing cellular machine, and it provides a framework for uncovering the engineering principles that underlie the secretory pathway. DOI:http://dx.doi.org/10.7554/eLife.13232.002
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Affiliation(s)
- Effrosyni Papanikou
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Kasey J Day
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Jotham Austin
- Electron Microscopy Core Facility, The University of Chicago, Chicago, United States
| | - Benjamin S Glick
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
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Lee M, Ko YJ, Moon Y, Han M, Kim HW, Lee SH, Kang K, Jun Y. SNAREs support atlastin-mediated homotypic ER fusion in Saccharomyces cerevisiae. J Cell Biol 2015. [PMID: 26216899 PMCID: PMC4523606 DOI: 10.1083/jcb.201501043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dynamin-like GTPases of the atlastin family are thought to mediate homotypic endoplasmic reticulum (ER) membrane fusion; however, the underlying mechanism remains largely unclear. Here, we developed a simple and quantitative in vitro assay using isolated yeast microsomes for measuring yeast atlastin Sey1p-dependent ER fusion. Using this assay, we found that the ER SNAREs Sec22p and Sec20p were required for Sey1p-mediated ER fusion. Consistently, ER fusion was significantly reduced by inhibition of Sec18p and Sec17p, which regulate SNARE-mediated membrane fusion. The involvement of SNAREs in Sey1p-dependent ER fusion was further supported by the physical interaction of Sey1p with Sec22p and Ufe1p, another ER SNARE. Furthermore, our estimation of the concentration of Sey1p on isolated microsomes, together with the lack of fusion between Sey1p proteoliposomes even with a 25-fold excess of the physiological concentration of Sey1p, suggests that Sey1p requires additional factors to support ER fusion in vivo. Collectively, our data strongly suggest that SNARE-mediated membrane fusion is involved in atlastin-initiated homotypic ER fusion.
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Affiliation(s)
- Miriam Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Integrative Aging Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Young-Joon Ko
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Integrative Aging Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Yeojin Moon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Integrative Aging Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Minsoo Han
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Integrative Aging Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Hyung-Wook Kim
- College of Life Sciences, Sejong University, Seoul 143-747, Korea
| | - Sung Haeng Lee
- Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju 501-759, Korea
| | - KyeongJin Kang
- Department of Anatomy and Cell Biology, School of Medicine, Sungkyunkwan University, Suwon 440-746, Korea
| | - Youngsoo Jun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Integrative Aging Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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41
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Hierro A, Gershlick DC, Rojas AL, Bonifacino JS. Formation of Tubulovesicular Carriers from Endosomes and Their Fusion to the trans-Golgi Network. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 318:159-202. [PMID: 26315886 DOI: 10.1016/bs.ircmb.2015.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Endosomes undergo extensive spatiotemporal rearrangements as proteins and lipids flux through them in a series of fusion and fission events. These controlled changes enable the concentration of cargo for eventual degradation while ensuring the proper recycling of other components. A growing body of studies has now defined multiple recycling pathways from endosomes to the trans-Golgi network (TGN) which differ in their molecular machineries. The recycling process requires specific sets of lipids, coats, adaptors, and accessory proteins that coordinate cargo selection with membrane deformation and its association with the cytoskeleton. Specific tethering factors and SNARE (SNAP (Soluble NSF Attachment Protein) Receptor) complexes are then required for the docking and fusion with the acceptor membrane. Herein, we summarize some of the current knowledge of the machineries that govern the retrograde transport from endosomes to the TGN.
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Affiliation(s)
- Aitor Hierro
- Structural Biology Unit, CIC bioGUNE, Derio, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - David C Gershlick
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | | | - Juan S Bonifacino
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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42
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Kuhlee A, Raunser S, Ungermann C. Functional homologies in vesicle tethering. FEBS Lett 2015; 589:2487-97. [PMID: 26072291 DOI: 10.1016/j.febslet.2015.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 05/30/2015] [Accepted: 06/01/2015] [Indexed: 11/24/2022]
Abstract
The HOPS multisubunit tethering factor (MTC) is a macromolecular protein complex composed of six different subunits. It is one of the key components in the perception and subsequent fusion of multivesicular bodies and vacuoles. Electron microscopy studies indicate structural flexibility of the purified HOPS complex. Inducing higher rigidity into HOPS by biochemically modifying the complex declines the potential to mediate SNARE-driven membrane fusion. Thus, we propose that integral flexibility seems to be not only a feature, but of essential need for the function of HOPS. This review focuses on the general features of membrane tethering and fusion. For this purpose, we compare the structure and mode of action of different tethering factors to highlight their common central features and mechanisms.
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Affiliation(s)
- Anne Kuhlee
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Christian Ungermann
- Department of Biology, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
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43
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Molecular dynamics at the endocytic portal and regulations of endocytic and recycling traffics. Eur J Cell Biol 2015; 94:235-48. [DOI: 10.1016/j.ejcb.2015.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/02/2015] [Accepted: 04/08/2015] [Indexed: 02/01/2023] Open
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Schultzhaus Z, Yan H, Shaw BD. Aspergillus nidulansflippase DnfA is cargo of the endocytic collar and plays complementary roles in growth and phosphatidylserine asymmetry with another flippase, DnfB. Mol Microbiol 2015; 97:18-32. [DOI: 10.1111/mmi.13019] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Zachary Schultzhaus
- Department of Plant Pathology and Microbiology; Texas A&M University; College Station TX USA
| | - Huijuan Yan
- Department of Plant Protection; Fujian Agricultural and Forestry University; Fuzhou Fujian China
| | - Brian D. Shaw
- Department of Plant Pathology and Microbiology; Texas A&M University; College Station TX USA
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45
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Rosa-Ferreira C, Christis C, Torres IL, Munro S. The small G protein Arl5 contributes to endosome-to-Golgi traffic by aiding the recruitment of the GARP complex to the Golgi. Biol Open 2015; 4:474-81. [PMID: 25795912 PMCID: PMC4400590 DOI: 10.1242/bio.201410975] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The small G proteins of the Arf family play critical roles in membrane trafficking and cytoskeleton organization. However, the function of some members of the family remains poorly understood including Arl5 which is widely conserved in eukaryotes. Humans have two closely related Arl5 paralogues (Arl5a and Arl5b), and both Arl5a and Arl5b localize to the trans-Golgi with Arl5b being involved in retrograde traffic from endosomes to the Golgi apparatus. To investigate the function of Arl5, we have used Drosophila melanogaster as a model system. We find that the single Arl5 orthologue in Drosophila also localizes to the trans-Golgi, but flies lacking the Arl5 gene are viable and fertile. By using both liposome and column based affinity chromatography methods we find that Arl5 interacts with the Golgi-associated retrograde protein (GARP) complex that acts in the tethering of vesicles moving from endosomes to the trans-Golgi network (TGN). In Drosophila tissues the GARP complex is partially displaced from the Golgi when Arl5 is absent, and the late endosomal compartment is enlarged. In addition, in HeLa cells GARP also becomes cytosolic upon depletion of Arl5b. These phenotypes are consistent with a role in endosome-to-Golgi traffic, but are less severe than loss of GARP itself. Thus it appears that Arl5 is one of the factors that directs the recruitment of the GARP complex to the trans-Golgi, and this function is conserved in both flies and humans.
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Affiliation(s)
| | | | | | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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46
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Wang T, Grabski R, Sztul E, Hay JC. p115-SNARE interactions: a dynamic cycle of p115 binding monomeric SNARE motifs and releasing assembled bundles. Traffic 2015; 16:148-71. [PMID: 25406594 DOI: 10.1111/tra.12242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 11/30/2022]
Abstract
Tethering factors regulate the targeting of membrane-enclosed vesicles under the control of Rab GTPases. p115, a golgin family tether, has been shown to participate in multiple stages of ER/Golgi transport. Despite extensive study, the mechanism of action of p115 is poorly understood. SNARE proteins make up the machinery for membrane fusion, and strong evidence shows that function of p115 is directly linked to its interaction with SNAREs. Using a gel filtration binding assay, we have demonstrated that in solution p115 stably interacts with ER/Golgi SNAREs rbet1 and sec22b, but not membrin and syntaxin 5. These binding preferences stemmed from selectivity of p115 for monomeric SNARE motifs as opposed to SNARE oligomers. Soluble monomeric rbet1 can compete off p115 from coat protein II (COPII) vesicles. Furthermore, excess p115 inhibits p115 function in trafficking. We conclude that monomeric SNAREs are a major binding site for p115 on COPII vesicles, and that p115 dissociates from its SNARE partners upon SNAREpin assembly. Our results suggest a model in which p115 forms a mixed p115/SNARE helix bundle with a monomeric SNARE, facilitates the binding activity and/or concentration of the SNARE at prefusion sites and is subsequently ejected as SNARE complex formation and fusion proceed.
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Affiliation(s)
- Ting Wang
- Division of Biological Sciences and Center for Structural & Functional Neuroscience, The University of Montana, Missoula, MT, USA
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47
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Sánchez-León E, Bowman B, Seidel C, Fischer R, Novick P, Riquelme M. The Rab GTPase YPT-1 associates with Golgi cisternae and Spitzenkörper microvesicles inNeurospora crassa. Mol Microbiol 2014; 95:472-90. [DOI: 10.1111/mmi.12878] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2014] [Indexed: 02/02/2023]
Affiliation(s)
- Eddy Sánchez-León
- Department of Microbiology; Center for Scientific Research and Higher Education of Ensenada (CICESE); Ensenada Baja California Mexico
| | - Barry Bowman
- Department of Molecular, Cell and Developmental Biology; University of California; Santa Cruz CA USA
| | - Constanze Seidel
- Department of Applied Microbiology; Karlsruhe Institute of Technology; Karlsruhe Germany
| | - Reinhard Fischer
- Department of Applied Microbiology; Karlsruhe Institute of Technology; Karlsruhe Germany
| | - Peter Novick
- Department of Cellular and Molecular Medicine; University of California; San Diego CA USA
| | - Meritxell Riquelme
- Department of Microbiology; Center for Scientific Research and Higher Education of Ensenada (CICESE); Ensenada Baja California Mexico
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Becuwe M, Léon S. Integrated control of transporter endocytosis and recycling by the arrestin-related protein Rod1 and the ubiquitin ligase Rsp5. eLife 2014; 3. [PMID: 25380227 PMCID: PMC4244573 DOI: 10.7554/elife.03307] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 11/04/2014] [Indexed: 01/04/2023] Open
Abstract
After endocytosis, membrane proteins can recycle to the cell membrane or be degraded in lysosomes. Cargo ubiquitylation favors their lysosomal targeting and can be regulated by external signals, but the mechanism is ill-defined. Here, we studied the post-endocytic trafficking of Jen1, a yeast monocarboxylate transporter, using microfluidics-assisted live-cell imaging. We show that the ubiquitin ligase Rsp5 and the glucose-regulated arrestin-related trafficking adaptors (ART) protein Rod1, involved in the glucose-induced internalization of Jen1, are also required for the post-endocytic sorting of Jen1 to the yeast lysosome. This new step takes place at the trans-Golgi network (TGN), where Rod1 localizes dynamically upon triggering endocytosis. Indeed, transporter trafficking to the TGN after internalization is required for their degradation. Glucose removal promotes Rod1 relocalization to the cytosol and Jen1 deubiquitylation, allowing transporter recycling when the signal is only transient. Therefore, nutrient availability regulates transporter fate through the localization of the ART/Rsp5 ubiquitylation complex at the TGN. DOI:http://dx.doi.org/10.7554/eLife.03307.001 The plasma membrane that surrounds cells contains many different proteins that perform tasks such as detecting signals sent to the cell, and transporting molecules into or out of the cell. To adapt to changing conditions, cells remodel their membrane to change how much of each type of protein is present. A process called endocytosis—where part of the plasma membrane and the proteins it contains buds off into the cell—plays an important role in this remodeling. The fate of a membrane protein after endocytosis can depend on whether a protein ‘tag’ called ubiquitin has been added to it. Ubiquitin-marked proteins bud off into the cell and are then sent to cell structures called lysosomes to be degraded, whereas unmarked proteins are recycled back to the plasma membrane. Yeast cell membranes contain a protein called Jen1 that transports certain molecules, including one called lactate that can be used as fuel for growth. However, glucose is a preferred nutrient for yeast, so when glucose is available, another protein called Rod1 becomes activated and promotes the addition of ubiquitin to Jen1, and hence its degradation. This means that the cells can no longer use lactate as a source of energy. However, it was not known where in the cell the Rod1 protein does this. Becuwe and Léon labeled proteins involved in endocytosis with fluorescent tags and used microscopy to observe their fate in live yeast cells exposed to glucose. This revealed two roles for Rod1. At the plasma membrane, Rod1 helps Jen1 to be taken into the cell in the early stages of endocytosis. But unexpectedly, Rod1 is also found at a cellular structure called the trans-Golgi network, small membrane sacs that are typically responsible for packaging proteins so they can be transported to a new destination, in particular the plasma membrane. This suggests that Rod1 can also act at this location in the cell. When the proteins responsible for maintaining transport to the trans-Golgi network are inhibited, Jen1 is no longer degraded, even when glucose is present; instead, Jen1 is recycled back to the plasma membrane. Becuwe and Léon therefore propose that a second level of control of the degradation of plasma membrane proteins occurs in the trans-Golgi network, and so this compartment has an essential role in sorting proteins for degradation or recycling. The group of proteins that Rod1 belongs to, named arrestins, has been suggested to play important roles in several diseases, including diabetes and cancer. As many of the features of the endocytic pathway are conserved in a broad range of species, arrestins may also be important for controlling the fate of membrane proteins at multiple places in mammalian cells. However, further work is required to confirm this. DOI:http://dx.doi.org/10.7554/eLife.03307.002
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Affiliation(s)
- Michel Becuwe
- Department of Cell Biology, Institut Jacques Monod, Université Paris-Diderot, CNRS, Paris, France
| | - Sébastien Léon
- Department of Cell Biology, Institut Jacques Monod, Université Paris-Diderot, CNRS, Paris, France
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49
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Brunet S, Sacher M. Are all multisubunit tethering complexes bona fide tethers? Traffic 2014; 15:1282-7. [PMID: 25048641 DOI: 10.1111/tra.12200] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 01/15/2023]
Abstract
Since the late 1990s, a number of multisubunit tethering complexes (MTCs) have been described that function in membrane trafficking events: TRAPP I, TRAPP II, TRAPP III, COG, HOPS, CORVET, Dsl1, GARP and exocyst. On the basis of structural and sequence similarities, they have been categorized as complexes associated with tethering containing helical rods (CATCHR) (Dsl1, COG, GARP and exocyst) or non-CATCHR (TRAPP I, II and III, HOPS and CORVET) complexes (Yu IM, Hughson FM. Tethering factors as organizers of intracellular vesicular traffic. Annu Rev Cell Dev Biol 2010;26:137-156). Both acronyms (CATCHR and MTC) imply these complexes tether opposing membranes to facilitate fusion. The main question we will address is: have these complexes been formally demonstrated to function as tethers? If the answer is no, then is it premature or even correct to refer to them as tethers? In this commentary, we will argue that the vast majority of MTCs have not been demonstrated to act as a tether. We propose that a distinction between the terms tether and tethering factor be considered to address this issue.
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Affiliation(s)
- Stephanie Brunet
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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50
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Abstract
Membrane trafficking depends on transport vesicles and carriers docking and fusing with the target organelle for the delivery of cargo. Membrane tethers and small guanosine triphosphatases (GTPases) mediate the docking of transport vesicles/carriers to enhance the efficiency of the subsequent SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor)-mediated fusion event with the target membrane bilayer. Different classes of membrane tethers and their specific intracellular location throughout the endomembrane system are now well defined. Recent biochemical and structural studies have led to a deeper understanding of the mechanism by which membrane tethers mediate docking of membrane carriers as well as an appreciation of the role of tethers in coordinating the correct SNARE complex and in regulating the organization of membrane compartments. This review will summarize the properties and roles of membrane tethers of both secretory and endocytic systems.
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Affiliation(s)
- Pei Zhi Cheryl Chia
- National Institute of Dental and Craniofacial Research, National Institutes of Health30 Convent Drive, Bethesda, MD 20892-4340USA
| | - Paul A. Gleeson
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute30 Flemington Road, The University of Melbourne, Victoria 3010Australia
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