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Cattin-Ortolá J, Kaufman JGG, Gillingham AK, Wagstaff JL, Peak-Chew SY, Stevens TJ, Boulanger J, Owen DJ, Munro S. Cargo selective vesicle tethering: The structural basis for binding of specific cargo proteins by the Golgi tether component TBC1D23. SCIENCE ADVANCES 2024; 10:eadl0608. [PMID: 38552021 DOI: 10.1126/sciadv.adl0608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 02/26/2024] [Indexed: 04/02/2024]
Abstract
The Golgi-localized golgins golgin-97 and golgin-245 capture transport vesicles arriving from endosomes via the protein TBC1D23. The amino-terminal domain of TBC1D23 binds to the golgins, and the carboxyl-terminal domain of TBC1D23 captures the vesicles, but how it recognizes specific vesicles was unclear. A search for binding partners of the carboxyl-terminal domain unexpectedly revealed direct binding to carboxypeptidase D and syntaxin-16, known cargo proteins of the captured vesicles. Binding is via a threonine-leucine-tyrosine (TLY) sequence present in both proteins next to an acidic cluster. A crystal structure reveals how this acidic TLY motif binds to TBC1D23. An acidic TLY motif is also present in the tails of other endosome-to-Golgi cargo, and these also bind TBC1D23. Structure-guided mutations in the carboxyl-terminal domain that disrupt motif binding in vitro also block vesicle capture in vivo. Thus, TBC1D23 attached to golgin-97 and golgin-245 captures vesicles by a previously undescribed mechanism: the recognition of a motif shared by cargo proteins carried by the vesicle.
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Affiliation(s)
- Jérôme Cattin-Ortolá
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Jonathan G G Kaufman
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Alison K Gillingham
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Jane L Wagstaff
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Sew-Yeu Peak-Chew
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Tim J Stevens
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Jérôme Boulanger
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - David J Owen
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
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2
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Griffin EN, Jucius T, Sim SE, Harris BS, Heinz S, Ackerman SL. RREB1 regulates neuronal proteostasis and the microtubule network. SCIENCE ADVANCES 2024; 10:eadh3929. [PMID: 38198538 PMCID: PMC10780896 DOI: 10.1126/sciadv.adh3929] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 12/12/2023] [Indexed: 01/12/2024]
Abstract
Transcription factors play vital roles in neuron development; however, little is known about the role of these proteins in maintaining neuronal homeostasis. Here, we show that the transcription factor RREB1 (Ras-responsive element-binding protein 1) is essential for neuron survival in the mammalian brain. A spontaneous mouse mutation causing loss of a nervous system-enriched Rreb1 transcript is associated with progressive loss of cerebellar Purkinje cells and ataxia. Analysis of chromatin immunoprecipitation and sequencing, along with RNA sequencing data revealed dysregulation of RREB1 targets associated with the microtubule cytoskeleton. In agreement with the known role of microtubules in dendritic development, dendritic complexity was disrupted in Rreb1-deficient neurons. Analysis of sequencing data also suggested that RREB1 plays a role in the endomembrane system. Mutant Purkinje cells had fewer numbers of autophagosomes and lysosomes and contained P62- and ubiquitin-positive inclusions. Together, these studies demonstrate that RREB1 functions to maintain the microtubule network and proteostasis in mammalian neurons.
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Affiliation(s)
- Emily N. Griffin
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Department of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Thomas Jucius
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Department of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Su-Eon Sim
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Department of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Sven Heinz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L. Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Department of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
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3
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Song R, McAlpine W, Fond AM, Nair-Gill E, Choi JH, Nyström EEL, Arike L, Field S, Li X, SoRelle JA, Moresco JJ, Moresco EMY, Yates JR, Azadi P, Ni J, Birchenough GMH, Beutler B, Turer EE. Trans-Golgi protein TVP23B regulates host-microbe interactions via Paneth cell homeostasis and Goblet cell glycosylation. Nat Commun 2023; 14:3652. [PMID: 37339972 PMCID: PMC10282085 DOI: 10.1038/s41467-023-39398-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 06/09/2023] [Indexed: 06/22/2023] Open
Abstract
A key feature in intestinal immunity is the dynamic intestinal barrier, which separates the host from resident and pathogenic microbiota through a mucus gel impregnated with antimicrobial peptides. Using a forward genetic screen, we have found a mutation in Tvp23b, which conferred susceptibility to chemically induced and infectious colitis. Trans-Golgi apparatus membrane protein TVP23 homolog B (TVP23B) is a transmembrane protein conserved from yeast to humans. We found that TVP23B controls the homeostasis of Paneth cells and function of goblet cells, leading to a decrease in antimicrobial peptides and more penetrable mucus layer. TVP23B binds with another Golgi protein, YIPF6, which is similarly critical for intestinal homeostasis. The Golgi proteomes of YIPF6 and TVP23B-deficient colonocytes have a common deficiency of several critical glycosylation enzymes. TVP23B is necessary for the formation of the sterile mucin layer of the intestine and its absence disturbs the balance of host and microbe in vivo.
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Affiliation(s)
- Ran Song
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - William McAlpine
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Aaron M Fond
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Evan Nair-Gill
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Jin Huk Choi
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Elisabeth E L Nyström
- Institute of Biochemistry, University of Kiel, 24118, Kiel, Schleswig-Holstein, Germany
| | - Liisa Arike
- The Wallenberg Centre for Molecular & Translational Medicine, Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Sydney Field
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Xiaohong Li
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Jeffrey A SoRelle
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - James J Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Eva Marie Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Josephine Ni
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - George M H Birchenough
- The Wallenberg Centre for Molecular & Translational Medicine, Department of Medical Biochemistry, Institute of Biomedicine, University of Gothenburg, 40530, Gothenburg, Sweden
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA
| | - Emre E Turer
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA.
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-8505, USA.
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4
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Shin JJH, Crook OM, Borgeaud AC, Cattin-Ortolá J, Peak-Chew SY, Breckels LM, Gillingham AK, Chadwick J, Lilley KS, Munro S. Spatial proteomics defines the content of trafficking vesicles captured by golgin tethers. Nat Commun 2020; 11:5987. [PMID: 33239640 PMCID: PMC7689464 DOI: 10.1038/s41467-020-19840-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023] Open
Abstract
Intracellular traffic between compartments of the secretory and endocytic pathways is mediated by vesicle-based carriers. The proteomes of carriers destined for many organelles are ill-defined because the vesicular intermediates are transient, low-abundance and difficult to purify. Here, we combine vesicle relocalisation with organelle proteomics and Bayesian analysis to define the content of different endosome-derived vesicles destined for the trans-Golgi network (TGN). The golgin coiled-coil proteins golgin-97 and GCC88, shown previously to capture endosome-derived vesicles at the TGN, were individually relocalised to mitochondria and the content of the subsequently re-routed vesicles was determined by organelle proteomics. Our findings reveal 45 integral and 51 peripheral membrane proteins re-routed by golgin-97, evidence for a distinct class of vesicles shared by golgin-97 and GCC88, and various cargoes specific to individual golgins. These results illustrate a general strategy for analysing intracellular sub-proteomes by combining acute cellular re-wiring with high-resolution spatial proteomics.
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Affiliation(s)
- John J H Shin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| | - Oliver M Crook
- The Milner Therapeutics Institute, University of Cambridge, Cambridge, CB2 0AW, UK
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QR, UK
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, CB2 0SR, UK
| | - Alicia C Borgeaud
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Jérôme Cattin-Ortolá
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Sew Y Peak-Chew
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Lisa M Breckels
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QR, UK
| | - Alison K Gillingham
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Jessica Chadwick
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Kathryn S Lilley
- The Milner Therapeutics Institute, University of Cambridge, Cambridge, CB2 0AW, UK
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QR, UK
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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5
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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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6
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Identifying novel members of the Wntless interactome through genetic and candidate gene approaches. Brain Res Bull 2017; 138:96-105. [PMID: 28734904 DOI: 10.1016/j.brainresbull.2017.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/26/2017] [Accepted: 07/06/2017] [Indexed: 02/07/2023]
Abstract
Wnt signaling is an important pathway that regulates several aspects of embryogenesis, stem cell maintenance, and neural connectivity. We have recently determined that opioids decrease Wnt secretion, presumably by inhibiting the recycling of the Wnt trafficking protein Wntless (Wls). This effect appears to be mediated by protein-protein interaction between Wls and the mu-opioid receptor (MOR), the primary cellular target of opioid drugs. The goal of this study was to identify novel protein interactors of Wls that are expressed in the brain and may also play a role in reward or addiction. Using genetic and candidate gene approaches, we show that among a variety of protein, Wls interacts with the dopamine transporter (target of cocaine), cannabinoid receptors (target of THC), Adenosine A2A receptor (target of caffeine), and SGIP1 (endocytic regulator of cannabinoid receptors). Our study shows that aside from opioid receptors, Wntless interacts with additional proteins involved in reward and/or addiction. Future studies will determine whether Wntless and WNT signaling play a more universal role in these processes.
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7
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McFarlane HE, Watanabe Y, Gendre D, Carruthers K, Levesque-Tremblay G, Haughn GW, Bhalerao RP, Samuels L. Cell wall polysaccharides are mislocalized to the Vacuole in echidna mutants. PLANT & CELL PHYSIOLOGY 2013; 54:1867-1880. [PMID: 24058145 DOI: 10.1093/pcp/pct129] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
During cell wall biosynthesis, the Golgi apparatus is the platform for cell wall matrix biosynthesis and the site of packaging, of both matrix polysaccharides and proteins, into secretory vesicles with the correct targeting information. The objective of this study was to dissect the post-Golgi trafficking of cell wall polysaccharides using echidna as a vesicle traffic mutant of Arabidopsis thaliana and the pectin-secreting cells of the seed coat as a model system. ECHIDNA encodes a trans-Golgi network (TGN)-localized protein, which was previously shown to be required for proper structure and function of the secretory pathway. In echidna mutants, some cell wall matrix polysaccharides accumulate inside cells, rather than being secreted to the apoplast. In this study, live cell imaging of fluorescent protein markers as well as transmission electron microscopy (TEM)/immunoTEM of cryofixed seed coat cells were used to examine the consequences of TGN disorganization in echidna mutants under conditions of high polysaccharide production and secretion. While in wild-type seed coat cells, pectin is secreted to the apical surface, in echidna, polysaccharides accumulate in post-Golgi vesicles, the central lytic vacuole and endoplasmic reticulum-derived bodies. In contrast, proteins were partially mistargeted to internal multilamellar membranes in echidna. These results suggest that while secretion of both cell wall polysaccharides and proteins at the TGN requires ECHIDNA, different vesicle trafficking components may mediate downstream events in their secretion from the TGN.
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Affiliation(s)
- Heather E McFarlane
- Department of Botany, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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8
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Gendre D, McFarlane HE, Johnson E, Mouille G, Sjödin A, Oh J, Levesque-Tremblay G, Watanabe Y, Samuels L, Bhalerao RP. Trans-Golgi network localized ECHIDNA/Ypt interacting protein complex is required for the secretion of cell wall polysaccharides in Arabidopsis. THE PLANT CELL 2013; 25:2633-46. [PMID: 23832588 PMCID: PMC3753388 DOI: 10.1105/tpc.113.112482] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The secretion of cell wall polysaccharides through the trans-Golgi network (TGN) is required for plant cell elongation. However, the components mediating the post-Golgi secretion of pectin and hemicellulose, the two major cell wall polysaccharides, are largely unknown. We identified evolutionarily conserved YPT/RAB GTPase Interacting Protein 4a (YIP4a) and YIP4b (formerly YIP2), which form a TGN-localized complex with ECHIDNA (ECH) in Arabidopsis thaliana. The localization of YIP4 and ECH proteins at the TGN is interdependent and influences the localization of VHA-a1 and SYP61, which are key components of the TGN. YIP4a and YIP4b act redundantly, and the yip4a yip4b double mutants have a cell elongation defect. Genetic, biochemical, and cell biological analyses demonstrate that the ECH/YIP4 complex plays a key role in TGN-mediated secretion of pectin and hemicellulose to the cell wall in dark-grown hypocotyls and in secretory cells of the seed coat. In keeping with these observations, Fourier transform infrared microspectroscopy analysis revealed that the ech and yip4a yip4b mutants exhibit changes in their cell wall composition. Overall, our results reveal a TGN subdomain defined by ECH/YIP4 that is required for the secretion of pectin and hemicellulose and distinguishes the role of the TGN in secretion from its roles in endocytic and vacuolar trafficking.
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Affiliation(s)
- Delphine Gendre
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | - Heather E. McFarlane
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Errin Johnson
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | - Gregory Mouille
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Institut National de la Recherche Agronomique Centre de Versailles-Grignon, 78026 Versailles cedex, France
| | - Andreas Sjödin
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | - Jaesung Oh
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
| | | | - Yoichiro Watanabe
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Lacey Samuels
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Rishikesh P. Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83 Umea, Sweden
- Address correspondence to
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9
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Gossing M, Chidambaram S, Fischer von Mollard G. Importance of the N-terminal domain of the Qb-SNARE Vti1p for different membrane transport steps in the yeast endosomal system. PLoS One 2013; 8:e66304. [PMID: 23776654 PMCID: PMC3680383 DOI: 10.1371/journal.pone.0066304] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 05/04/2013] [Indexed: 01/11/2023] Open
Abstract
SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) on transport vesicles and target membranes are crucial for vesicle targeting and fusion. They form SNARE complexes, which contain four α-helical SNARE motifs contributed by three or four different SNAREs. Most SNAREs function only in a single transport step. The yeast SNARE Vti1p participates in four distinct SNARE complexes in transport from the trans Golgi network to late endosomes, in transport to the vacuole, in retrograde transport from endosomes to the trans Golgi network and in retrograde transport within the Golgi. So far, all vti1 mutants investigated had mutations within the SNARE motif. Little is known about the function of the N-terminal domain of Vti1p, which forms a three helix bundle called Habc domain. Here we generated a temperature-sensitive mutant of this domain to study the effects on different transport steps. The secondary structure of wild type and vti1-3 Habc domain was analyzed by circular dichroism spectroscopy. The amino acid exchanges identified in the temperature-sensitive vti1-3 mutant caused unfolding of the Habc domain. Transport pathways were investigated by immunoprecipitation of newly synthesized proteins after pulse-chase labeling and by fluorescence microscopy of a GFP-tagged protein cycling between plasma membrane, early endosomes and Golgi. In vti1-3 cells transport to the late endosome and assembly of the late endosomal SNARE complex was blocked at 37°C. Retrograde transport to the trans Golgi network was affected while fusion with the vacuole was possible but slower. Steady state levels of SNARE complexes mediating these steps were less affected than that of the late endosomal SNARE complex. As different transport steps were affected our data demonstrate the importance of a folded Vti1p Habc domain for transport.
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Affiliation(s)
- Michael Gossing
- Biochemie III, Fakultät für Chemie, Universität Bielefeld, Bielefeld, Germany
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10
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Marešová L, Vydarený T, Sychrová H. Comparison of the influence of small GTPases Arl1 and Ypt6 on yeast cells' tolerance to various stress factors. FEMS Yeast Res 2012; 12:332-40. [PMID: 22188384 DOI: 10.1111/j.1567-1364.2011.00780.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 11/22/2011] [Accepted: 12/08/2011] [Indexed: 11/30/2022] Open
Abstract
The GTPases Arl1 and Ypt6 are involved in the intracellular transport of vesicles and their fusion with the trans-Golgi network. This work is focused on comparing the roles of these GTPases in the tolerance of Saccharomyces cerevisiae cells to an increased concentration of alkali metal cations and other stress factors. We studied the phenotypes of arl1 or ypt6 deletions in combination with the deletions of genes encoding alkali-metal-cation transporters (ena1-4, nha1, nhx1, and kha1). Salt sensitivity of the arl1 and ypt6 mutants was shown to be independent of the tested cation transporters and electrochemical membrane potential. Phenotype manifestations of ypt6 deletion were usually more prominent than those of arl1 (cells were more sensitive to KCl, NaCl, LiCl, hygromycin B, increased temperature, and increased pH). At suboptimal temperature, the growth inhibition of arl1 and ypt6 mutants was approximately the same, and low pH was the only condition where arl1 mutants grew even worse than ypt6 mutants. Overexpression of the ARL1 gene suppressed the phenotypes of ypt6 deletion; however, this did not work vice versa (additional copies of YPT6 could not replace ARL1). Our results suggest partially overlapping functions of the GTPases in resistance to various stress factors, with Ypt6 being more efficient under physiological conditions and Arl1 more versatile when overexpressed.
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Affiliation(s)
- Lydie Marešová
- Department of Membrane Transport, Institute of Physiology Academy of Sciences of the Czech Republic v.v.i., Prague, Czech Republic.
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11
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Conserved Arabidopsis ECHIDNA protein mediates trans-Golgi-network trafficking and cell elongation. Proc Natl Acad Sci U S A 2011; 108:8048-53. [PMID: 21512130 DOI: 10.1073/pnas.1018371108] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Multiple steps of plant growth and development rely on rapid cell elongation during which secretory and endocytic trafficking via the trans-Golgi network (TGN) plays a central role. Here, we identify the ECHIDNA (ECH) protein from Arabidopsis thaliana as a TGN-localized component crucial for TGN function. ECH partially complements loss of budding yeast TVP23 function and a Populus ECH complements the Arabidopsis ech mutant, suggesting functional conservation of the genes. Compared with wild-type, the Arabidopsis ech mutant exhibits severely perturbed cell elongation as well as defects in TGN structure and function, manifested by the reduced association between Golgi bodies and TGN as well as mislocalization of several TGN-localized proteins including vacuolar H(+)-ATPase subunit a1 (VHA-a1). Strikingly, ech is defective in secretory trafficking, whereas endocytosis appears unaffected in the mutant. Some aspects of the ech mutant phenotype can be phenocopied by treatment with a specific inhibitor of vacuolar H(+)-ATPases, concanamycin A, indicating that mislocalization of VHA-a1 may account for part of the defects in ech. Hence, ECH is an evolutionarily conserved component of the TGN with a central role in TGN structure and function.
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12
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Kanneganti V, Kama R, Gerst JE. Btn3 is a negative regulator of Btn2-mediated endosomal protein trafficking and prion curing in yeast. Mol Biol Cell 2011; 22:1648-63. [PMID: 21441304 PMCID: PMC3093318 DOI: 10.1091/mbc.e10-11-0878] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Btn2 is a Batten disease-related protein that mediates endosome-Golgi protein retrieval and prion curing in yeast. Here we characterize Btn3, a putative orthologue of a human complex I deficiency protein, as a Btn2-interacting protein and negative regulator. Thus endosomal proteins involved in disease onset may engage prion-clearing compartments. Yeast Btn2 facilitates the retrieval of specific proteins from late endosomes (LEs) to the Golgi, a process that may be adversely affected in Batten disease patients. We isolated the putative yeast orthologue of a human complex I deficiency gene, designated here as BTN3, as encoding a Btn2-interacting protein and negative regulator. First, yeast overexpressing BTN3 phenocopy the deletion of BTN2 and mislocalize certain trans-Golgi proteins, like Kex2 and Yif1, to the LE and vacuole, respectively. In contrast, the deletion of BTN3 results in a tighter pattern of protein localization to the Golgi. Second, BTN3 overexpression alters Btn2 localization from the IPOD compartment, which correlates with a sharp reduction in Btn2-mediated [URE3] prion curing. Third, Btn3 and the Snc1 v-SNARE compete for the same binding domain on Btn2, and this competition controls Btn2 localization and function. The inhibitory effects upon protein retrieval and prion curing suggest that Btn3 sequesters Btn2 away from its substrates, thus down-regulating protein trafficking and aggregation. Therefore Btn3 is a novel negative regulator of intracellular protein sorting, which may be of importance in the onset of complex I deficiency and Batten disease in humans.
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Affiliation(s)
- Vydehi Kanneganti
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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Marešová L, Sychrová H. Genetic interactions among the Arl1 GTPase and intracellular Na(+) /H(+) antiporters in pH homeostasis and cation detoxification. FEMS Yeast Res 2010; 10:802-11. [PMID: 20659170 DOI: 10.1111/j.1567-1364.2010.00661.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The roles of intracellular GTPase Arl1 and organellar cation/H(+) antiporters (Kha1 and Nhx1) in Saccharomyces cerevisiae tolerance to various stress factors were investigated and interesting new phenotypes of strains devoid of these proteins were found. The role of Arl1 GTPase in their tolerance to various cations is not caused by an altered plasma-membrane potential. Besides the known sensitivity of arl1 mutants to high temperature, we discovered their sensitivity to low temperature. We found for the first time that in the absence of Arl1p, Kha1p increases potassium, sodium and lithium tolerance, and can thus be categorized as an antiporter with broad substrate specificity. Kha1p also participates in the detoxification of undesired chemical compounds, pH regulation and growth at nonoptimal temperatures. Cells with the combined deletions of all three genes have considerable difficulty growing under nonoptimal conditions. We conclude that Arl1p, Kha1p and Nhx1p collaborate in survival strategies at nonoptimal pH, temperatures and cation concentrations, but work independent of each other.
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Affiliation(s)
- Lydie Marešová
- Department of Membrane Transport, Institute of Physiology Academy of Sciences of the Czech Republic v.v.i., Prague, Czech Republic.
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Wendler F, Gillingham AK, Sinka R, Rosa-Ferreira C, Gordon DE, Franch-Marro X, Peden AA, Vincent JP, Munro S. A genome-wide RNA interference screen identifies two novel components of the metazoan secretory pathway. EMBO J 2010; 29:304-14. [PMID: 19942856 PMCID: PMC2824459 DOI: 10.1038/emboj.2009.350] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 11/02/2009] [Indexed: 02/01/2023] Open
Abstract
Genetic screens in the yeast Saccharomyces cerevisiae have identified many proteins involved in the secretory pathway, most of which have orthologues in higher eukaryotes. To investigate whether there are additional proteins that are required for secretion in metazoans but are absent from yeast, we used genome-wide RNA interference (RNAi) to look for genes required for secretion of recombinant luciferase from Drosophila S2 cells. This identified two novel components of the secretory pathway that are conserved from humans to plants. Gryzun is distantly related to, but distinct from, the Trs130 subunit of the TRAPP complex but is absent from S. cerevisiae. RNAi of human Gryzun (C4orf41) blocks Golgi exit. Kish is a small membrane protein with a previously uncharacterised orthologue in yeast. The screen also identified Drosophila orthologues of almost 60% of the yeast genes essential for secretion. Given this coverage, the small number of novel components suggests that contrary to previous indications the number of essential core components of the secretory pathway is not much greater in metazoans than in yeasts.
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Affiliation(s)
- Franz Wendler
- MRC National Institute for Medical Research, London, UK
| | | | - Rita Sinka
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | - David E Gordon
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Andrew A Peden
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, UK
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Current awareness on yeast. Yeast 2009. [DOI: 10.1002/yea.1625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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