51
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Rana M, Lachmann J, Ungermann C. Identification of a Rab GTPase-activating protein cascade that controls recycling of the Rab5 GTPase Vps21 from the vacuole. Mol Biol Cell 2015; 26:2535-49. [PMID: 25971802 PMCID: PMC4571306 DOI: 10.1091/mbc.e15-02-0062] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/06/2015] [Indexed: 01/30/2023] Open
Abstract
Endocytic transport depends on two consecutive Rabs, Vps21 (Rab5 in metazoans) and Ypt7 (Rab7), which bind to effectors on early and late endosomes. This study now shows that inactivation of Vps21 via its GTPase-activating protein (GAP) Msb3 requires both Ypt7 and fusion with the vacuole. The data suggest an endosomal GAP cascade that includes the effector of Ypt7. Transport within the endocytic pathway depends on a consecutive function of the endosomal Rab5 and the late endosomal/lysosomal Rab7 GTPases to promote membrane recycling and fusion in the context of endosomal maturation. We previously identified the hexameric BLOC-1 complex as an effector of the yeast Rab5 Vps21, which also recruits the GTPase-activating protein (GAP) Msb3. This raises the question of when Vps21 is inactivated on endosomes. We provide evidence for a Rab cascade in which activation of the Rab7 homologue Ypt7 triggers inactivation of Vps21. We find that the guanine nucleotide exchange factor (GEF) of Ypt7 (the Mon1-Ccz1 complex) and BLOC-1 both localize to the same endosomes. Overexpression of Mon1-Ccz1, which generates additional Ypt7-GTP, or overexpression of activated Ypt7 promotes relocalization of Vps21 from endosomes to the endoplasmic reticulum (ER), which is indicative of Vps21 inactivation. This ER relocalization is prevented by loss of either BLOC-1 or Msb3, but it also occurs in mutants lacking endosome–vacuole fusion machinery such as the HOPS tethering complex, an effector of Ypt7. Importantly, BLOC-1 interacts with the HOPS on vacuoles, suggesting a direct Ypt7-dependent cross-talk. These data indicate that efficient Vps21 recycling requires both Ypt7 and endosome–vacuole fusion, thus suggesting extended control of a GAP cascade beyond Rab interactions.
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Affiliation(s)
- Meenakshi Rana
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Jens Lachmann
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
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52
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Bouchez I, Pouteaux M, Canonge M, Genet M, Chardot T, Guillot A, Froissard M. Regulation of lipid droplet dynamics in Saccharomyces cerevisiae depends on the Rab7-like Ypt7p, HOPS complex and V1-ATPase. Biol Open 2015; 4:764-75. [PMID: 25948753 PMCID: PMC4571102 DOI: 10.1242/bio.20148615] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
It has now been clearly shown that lipid droplets (LDs) play a dynamic role in the cell. This was reinforced by LD proteomics which suggest that a significant number of trafficking proteins are associated with this organelle. Using microscopy, we showed that LDs partly co-localize with the vacuole in S. cerevisiae. Immunoblot experiments confirmed the association of the vacuolar Rab GTPase Rab7-like Ypt7p with LDs. We observed an increase in fatty acid content and LD number in ypt7Δ mutant and also changes in LD morphology and intra LD fusions, revealing a direct role for Ypt7p in LD dynamics. Using co-immunoprecipitation, we isolated potential Ypt7p partners including, Vma13p, the H subunit of the V1 part of the vacuolar (H+) ATPase (V-ATPase). Deletion of the VMA13 gene, as well as deletion of three other subunits of the V1 part of the V-ATPase, also increased the cell fatty acid content and LD number. Mutants of the Homotypic fusion and vacuole protein sorting (HOPS) complex showed similar phenotypes. Here, we demonstrated that LD dynamics and membrane trafficking between the vacuole and LDs are regulated by the Rab7-like Ypt7p and are impaired when the HOPS complex and the V1 domain of the V-ATPase are defective.
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Affiliation(s)
- Isabelle Bouchez
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Marie Pouteaux
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Michel Canonge
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Mélanie Genet
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Thierry Chardot
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
| | - Alain Guillot
- MICALIS PAPPSO, UMR 1319 INRA, Domaine de Vilvert 78352, Jouy-en-Josas cedex, France MICALIS PAPPSO, UMR 1319 AgroParisTech, Domaine de Vilvert 78352, Jouy-en-Josas cedex, France
| | - Marine Froissard
- Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France
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53
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Morlon‐Guyot J, Pastore S, Berry L, Lebrun M, Daher W. Toxoplasma gondii
Vps11, a subunit of
HOPS
and
CORVET
tethering complexes, is essential for the biogenesis of secretory organelles. Cell Microbiol 2015; 17:1157-78. [DOI: 10.1111/cmi.12426] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 01/20/2015] [Accepted: 01/28/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Juliette Morlon‐Guyot
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Sandra Pastore
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Laurence Berry
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Maryse Lebrun
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
| | - Wassim Daher
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR5235 CNRS Université Montpellier Montpellier France
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54
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Arlt H, Auffarth K, Kurre R, Lisse D, Piehler J, Ungermann C. Spatiotemporal dynamics of membrane remodeling and fusion proteins during endocytic transport. Mol Biol Cell 2015; 26:1357-70. [PMID: 25657322 PMCID: PMC4454181 DOI: 10.1091/mbc.e14-08-1318] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Endosomal sorting requires consecutive steps of membrane remodeling and fusion in the course of endosomal maturation. Tracing of cargo relative to machinery reveals similar temporal localization of ESCRT and endosomal fusion machinery, which precedes the retromer complex. However, blocking fusion with the vacuole does not impair maturation. Organelles of the endolysosomal system undergo multiple fission and fusion events to combine sorting of selected proteins to the vacuole with endosomal recycling. This sorting requires a consecutive remodeling of the organelle surface in the course of endosomal maturation. Here we dissect the remodeling and fusion machinery on endosomes during the process of endocytosis. We traced selected GFP-tagged endosomal proteins relative to exogenously added fluorescently labeled α-factor on its way from the plasma membrane to the vacuole. Our data reveal that the machinery of endosomal fusion and ESCRT proteins has similar temporal localization on endosomes, whereas they precede the retromer cargo recognition complex. Neither deletion of retromer nor the fusion machinery with the vacuole affects this maturation process, although the kinetics seems to be delayed due to ESCRT deletion. Of importance, in strains lacking the active Rab7-like Ypt7 or the vacuolar SNARE fusion machinery, α-factor still proceeds to late endosomes with the same kinetics. This indicates that endosomal maturation is mainly controlled by the early endosomal fusion and remodeling machinery but not the downstream Rab Ypt7 or the SNARE machinery. Our data thus provide important further understanding of endosomal biogenesis in the context of cargo sorting.
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Affiliation(s)
- Henning Arlt
- Biochemistry Section, University of Osnabrück, 49076 Osnabrück, Germany
| | - Kathrin Auffarth
- Biochemistry Section, University of Osnabrück, 49076 Osnabrück, Germany
| | - Rainer Kurre
- Center of Advanced Light Microscopy, University of Osnabrück, 49076 Osnabrück, Germany
| | - Dominik Lisse
- Biophysics Section, University of Osnabrück, 49076 Osnabrück, Germany
| | - Jacob Piehler
- Biophysics Section, University of Osnabrück, 49076 Osnabrück, Germany
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55
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Bean BDM, Davey M, Snider J, Jessulat M, Deineko V, Tinney M, Stagljar I, Babu M, Conibear E. Rab5-family guanine nucleotide exchange factors bind retromer and promote its recruitment to endosomes. Mol Biol Cell 2015; 26:1119-28. [PMID: 25609093 PMCID: PMC4357511 DOI: 10.1091/mbc.e14-08-1281] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The retromer complex regulates vesicle transport at endosomes. Different members of the VPS9 domain–containing Rab5-family guanine nucleotide exchange factors interact with the yeast retromer complex and mediate its endosomal localization. The retromer complex facilitates the sorting of integral membrane proteins from the endosome to the late Golgi. In mammalian cells, the efficient recruitment of retromer to endosomes requires the lipid phosphatidylinositol 3-phosphate (PI3P) as well as Rab5 and Rab7 GTPases. However, in yeast, the role of Rabs in recruiting retromer to endosomes is less clear. We identified novel physical interactions between retromer and the Saccharomyces cerevisiae VPS9-domain Rab5-family guanine nucleotide exchange factors (GEFs) Muk1 and Vps9. Furthermore, we identified a new yeast VPS9 domain-containing protein, VARP-like 1 (Vrl1), which is related to the human VARP protein. All three VPS9 domain–containing proteins show localization to endosomes, and the presence of any one of them is necessary for the endosomal recruitment of retromer. We find that expression of an active VPS9-domain protein is required for correct localization of the phosphatidylinositol 3-kinase Vps34 and the production of endosomal PI3P. These results suggest that VPS9 GEFs promote retromer recruitment by establishing PI3P-enriched domains at the endosomal membrane. The interaction of retromer with distinct VPS9 GEFs could thus link GEF-dependent regulatory inputs to the temporal or spatial coordination of retromer assembly or function.
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Affiliation(s)
- Bjorn D M Bean
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Jamie Snider
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada Department of Biochemistry and Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A8, Canada
| | - Matthew Jessulat
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK S4S 0A2, Canada
| | - Viktor Deineko
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK S4S 0A2, Canada
| | - Matthew Tinney
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada Department of Biochemistry and Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A8, Canada
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK S4S 0A2, Canada
| | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
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56
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Priya A, Kalaidzidis IV, Kalaidzidis Y, Lambright D, Datta S. Molecular Insights into Rab7-Mediated Endosomal Recruitment of Core Retromer: Deciphering the Role of Vps26 and Vps35. Traffic 2014; 16:68-84. [DOI: 10.1111/tra.12237] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 10/31/2014] [Accepted: 10/31/2014] [Indexed: 12/31/2022]
Affiliation(s)
- Amulya Priya
- Department of Biological Sciences; Indian Institute of Science Education and Research Bhopal; ITI Gas Rahat Building Bhopal 462023 India
| | - Inna V Kalaidzidis
- Max Planck Institute of Molecular Cell Biology and Genetics; 108 Pfotenhauerstrasse Dresden 01307 Germany
| | - Yannis Kalaidzidis
- Max Planck Institute of Molecular Cell Biology and Genetics; 108 Pfotenhauerstrasse Dresden 01307 Germany
- Faculty of Bioengineering and Bioinformatics; Moscow State University; Moscow 119991 Russia
| | - David Lambright
- Program in Molecular Medicine; University of Massachusetts Medical School; 373 Plantation Street Worcester MA 01605 USA
| | - Sunando Datta
- Department of Biological Sciences; Indian Institute of Science Education and Research Bhopal; ITI Gas Rahat Building Bhopal 462023 India
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57
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Lachmann J, Ungermann C, Engelbrecht-Vandré S. Rab GTPases and tethering in the yeast endocytic pathway. Small GTPases 2014; 2:182-186. [PMID: 21776422 DOI: 10.4161/sgtp.2.3.16701] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 05/24/2011] [Accepted: 05/30/2011] [Indexed: 11/19/2022] Open
Abstract
Within eukaryotic cells, Rab GTPases control the maturation of early to late endosomes and their subsequent fusion with the vacuole. Within this ExtraView, we will focus on our recent findings regarding the activation of the Rab7 homolog Ypt7 in yeast and its interplay with the two multisubunit tethering complexes CORVET and HOPS.
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Affiliation(s)
- Jens Lachmann
- Department of Biology/Chemistry; Biochemistry Section; University of Osnabrück; Osnabrück, Germany
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58
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McGough IJ, Steinberg F, Gallon M, Yatsu A, Ohbayashi N, Heesom KJ, Fukuda M, Cullen PJ. Identification of molecular heterogeneity in SNX27-retromer-mediated endosome-to-plasma-membrane recycling. J Cell Sci 2014; 127:4940-53. [PMID: 25278552 PMCID: PMC4231307 DOI: 10.1242/jcs.156299] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Retromer is a protein assembly that orchestrates the sorting of transmembrane cargo proteins into endosome-to-Golgi and endosome-to-plasma-membrane transport pathways. Here, we have employed quantitative proteomics to define the interactome of human VPS35, the core retromer component. This has identified a number of new interacting proteins, including ankyrin-repeat domain 50 (ANKRD50), seriologically defined colon cancer antigen 3 (SDCCAG3) and VPS9-ankyrin-repeat protein (VARP, also known as ANKRD27). Depletion of these proteins resulted in trafficking defects of retromer-dependent cargo, but differential and cargo-specific effects suggested a surprising degree of functional heterogeneity in retromer-mediated endosome-to-plasma-membrane sorting. Extending this, suppression of the retromer-associated WASH complex did not uniformly affect retromer cargo, thereby confirming cargo-specific functions for retromer-interacting proteins. Further analysis of the retromer-VARP interaction identified a role for retromer in endosome-to-melanosome transport. Suppression of VPS35 led to mistrafficking of the melanogenic enzymes, tyrosinase and tryrosine-related protein 1 (Tyrp1), establishing that retromer acts in concert with VARP in this trafficking pathway. Overall, these data reveal hidden complexities in retromer-mediated sorting and open up new directions in our molecular understanding of this essential sorting complex.
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Affiliation(s)
- Ian J McGough
- The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Florian Steinberg
- The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Matthew Gallon
- The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Ayaka Yatsu
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Norihiko Ohbayashi
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Kate J Heesom
- Proteomics Facility, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Mitsunori Fukuda
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Peter J Cullen
- The Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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59
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Hönscher C, Mari M, Auffarth K, Bohnert M, Griffith J, Geerts W, van der Laan M, Cabrera M, Reggiori F, Ungermann C. Cellular Metabolism Regulates Contact Sites between Vacuoles and Mitochondria. Dev Cell 2014; 30:86-94. [DOI: 10.1016/j.devcel.2014.06.006] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 04/04/2014] [Accepted: 06/09/2014] [Indexed: 11/25/2022]
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60
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Gautreau A, Oguievetskaia K, Ungermann C. Function and regulation of the endosomal fusion and fission machineries. Cold Spring Harb Perspect Biol 2014; 6:6/3/a016832. [PMID: 24591520 DOI: 10.1101/cshperspect.a016832] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Organelles within the endomembrane system are connected via vesicle flux. Along the endocytic pathway, endosomes are among the most versatile organelles. They sort cargo through tubular protrusions for recycling or through intraluminal vesicles for degradation. Sorting involves numerous machineries, which mediate fission of endosomal transport intermediates and fusion with other endosomes or eventually with lysosomes. Here we review the recent advances in our understanding of these processes with a particular focus on the Rab GTPases, tethering factors, and retromer. The cytoskeleton has also been recently recognized as a central player in membrane dynamics of endosomes, and this review covers the regulation of the machineries that govern the formation of branched actin networks through the WASH and Arp2/3 complexes in relation with cargo recycling and endosomal fission.
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Affiliation(s)
- Alexis Gautreau
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS UPR3082, 91190 Gif-sur-Yvette, France
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61
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Krai P, Dalal S, Klemba M. Evidence for a Golgi-to-endosome protein sorting pathway in Plasmodium falciparum. PLoS One 2014; 9:e89771. [PMID: 24587025 PMCID: PMC3934947 DOI: 10.1371/journal.pone.0089771] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022] Open
Abstract
During the asexual intraerythrocytic stage, the malaria parasite Plasmodium falciparum must traffic newly-synthesized proteins to a broad array of destinations within and beyond the parasite's plasma membrane. In this study, we have localized two well-conserved protein components of eukaryotic endosomes, the retromer complex and the small GTPase Rab7, to define a previously-undescribed endosomal compartment in P. falciparum. Retromer and Rab7 co-localized to a small number of punctate structures within parasites. These structures, which we refer to as endosomes, lie in close proximity to the Golgi apparatus and, like the Golgi apparatus, are inherited by daughter merozoites. However, the endosome is clearly distinct from the Golgi apparatus as neither retromer nor Rab7 redistributed to the endoplasmic reticulum upon brefeldin A treatment. Nascent rhoptries (specialized secretory organelles required for invasion) developed adjacent to endosomes, an observation that suggests a role for the endosome in rhoptry biogenesis. A P. falciparum homolog of the sortilin family of protein sorting receptors (PfSortilin) was localized to the Golgi apparatus. Together, these results elaborate a putative Golgi-to-endosome protein sorting pathway in asexual blood stage parasites and suggest that one role of retromer is to mediate the retrograde transport of PfSortilin from the endosome to the Golgi apparatus.
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Affiliation(s)
- Priscilla Krai
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Seema Dalal
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Michael Klemba
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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62
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Abstract
The endosomal network comprises an interconnected network of membranous compartments whose primary function is to receive, dissociate, and sort cargo that originates from the plasma membrane and the biosynthetic pathway. A major challenge in cell biology is to achieve a thorough molecular description of how this network operates, and in so doing, how defects contribute to the etiology and pathology of human disease. We discuss the increasing body of evidence that implicates an ancient evolutionary conserved complex, termed "retromer," as a master conductor in the complex orchestration of multiple cargo-sorting events within the endosomal network.
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Affiliation(s)
- Christopher Burd
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520
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63
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Arlt H, Reggiori F, Ungermann C. Retromer and the dynamin Vps1 cooperate in the retrieval of transmembrane proteins from vacuoles. J Cell Sci 2014; 128:645-55. [DOI: 10.1242/jcs.132720] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Endosomes are dynamic organelles that need to combine the ability to successfully deliver proteins and lipids to the lysosome-like vacuole, and recycle others to the Golgi or the plasma membrane. We now show that retromer, implicated in retrieval of proteins from endosomes to the Golgi or to the plasma membrane, can act on vacuoles. We explore its function using an assay that allows us to dissect the required cofactors during recycling. We demonstrate that recycling of the transmembrane receptor Vps10 from vacuoles requires the retromer, the dynamin-like Vps1, and the Rab7 GTPase Ypt7. While retromer and Vps1 leave the vacuole together with the cargo, Ypt7 stays behind, in agreement with its regulatory function. Recycled cargo then accumulates at endosomes and later at the Golgi, implying consecutive sorting steps to the final destination. Our data further suggest that retromer and Vps1 are essential to maintain vacuole membrane organization. All together, our data demonstrate that retromer can cooperate with Vps1 and the Rab Ypt7 to clear the vacuole of selected membrane proteins.
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64
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Balderhaar HJK, Ungermann C. CORVET and HOPS tethering complexes - coordinators of endosome and lysosome fusion. J Cell Sci 2013; 126:1307-16. [PMID: 23645161 DOI: 10.1242/jcs.107805] [Citation(s) in RCA: 364] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Protein and lipid transport along the endolysosomal system of eukaryotic cells depends on multiple fusion and fission events. Over the past few years, the molecular constituents of both fission and fusion machineries have been identified. Here, we focus on the mechanism of membrane fusion at endosomes, vacuoles and lysosomes, and in particular on the role of the two homologous tethering complexes called CORVET and HOPS. Both complexes are heterohexamers; they share four subunits, interact with Rab GTPases and soluble NSF attachment protein receptors (SNAREs) and can tether membranes. Owing to the presence of specific subunits, CORVET is a Rab5 effector complex, whereas HOPS can bind efficiently to late endosomes and lysosomes through Rab7. Based on the recently described overall structure of the HOPS complex and a number of in vivo and in vitro analyses, important insights into their function have been obtained. Here, we discuss the general function of both complexes in yeast and in metazoan cells in the context of endosomal biogenesis and maturation.
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Affiliation(s)
- Henning J kleine Balderhaar
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry Section, Barbarastrasse 13, 49076 Osnabrück, Germany
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65
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Abstract
Retromer is an evolutionarily conserved protein complex composed of the VPS26, VPS29, and VPS35 proteins that selects and packages cargo proteins into transport carriers that export cargo from the endosome. The mechanisms by which retromer is recruited to the endosome and captures cargo are unknown. We show that membrane recruitment of retromer is mediated by bivalent recognition of an effector of PI3K, SNX3, and the RAB7A GTPase, by the VPS35 retromer subunit. These bivalent interactions prime retromer to capture integral membrane cargo, which enhances membrane association of retromer and initiates cargo sorting. The role of RAB7A is severely impaired by a mutation, K157N, that causes Charcot-Marie-Tooth neuropathy 2B. The results elucidate minimal requirements for retromer assembly on the endosome membrane and reveal how PI3K and RAB signaling are coupled to initiate retromer-mediated cargo export.
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66
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Abstract
Intracellular organelles, including endosomes, show differences not only in protein but also in lipid composition. It is becoming clear from the work of many laboratories that the mechanisms necessary to achieve such lipid segregation can operate at very different levels, including the membrane biophysical properties, the interactions with other lipids and proteins, and the turnover rates or distribution of metabolic enzymes. In turn, lipids can directly influence the organelle membrane properties by changing biophysical parameters and by recruiting partner effector proteins involved in protein sorting and membrane dynamics. In this review, we will discuss how lipids are sorted in endosomal membranes and how they impact on endosome functions.
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Affiliation(s)
- Christin Bissig
- Biochemistry Department, University of Geneva, 1211 Geneva 4, Switzerland
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67
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Katsiarimpa A, Kalinowska K, Anzenberger F, Weis C, Ostertag M, Tsutsumi C, Schwechheimer C, Brunner F, Hückelhoven R, Isono E. The deubiquitinating enzyme AMSH1 and the ESCRT-III subunit VPS2.1 are required for autophagic degradation in Arabidopsis. THE PLANT CELL 2013; 25:2236-52. [PMID: 23800962 PMCID: PMC3723623 DOI: 10.1105/tpc.113.113399] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In eukaryotes, posttranslational modification by ubiquitin regulates the activity and stability of many proteins and thus influences a variety of developmental processes as well as environmental responses. Ubiquitination also plays a critical role in intracellular trafficking by serving as a signal for endocytosis. We have previously shown that the Arabidopsis thaliana associated molecule with the SH3 domain of STAM3 (AMSH3) is a deubiquitinating enzyme (DUB) that interacts with endosomal complex required for transport-III (ESCRT-III) and is essential for intracellular transport and vacuole biogenesis. However, physiological functions of AMSH3 in the context of its ESCRT-III interaction are not well understood due to the severe seedling lethal phenotype of its null mutant. In this article, we show that Arabidopsis AMSH1, an AMSH3-related DUB, interacts with the ESCRT-III subunit vacuolar protein sorting2.1 (VPS2.1) and that impairment of both AMSH1 and VPS2.1 causes early senescence and hypersensitivity to artificial carbon starvation in the dark similar to previously reported autophagy mutants. Consistent with this, both mutants accumulate autophagosome markers and accumulate less autophagic bodies in the vacuole. Taken together, our results demonstrate that AMSH1 and the ESCRT-III-subunit VPS2.1 are important for autophagic degradation and autophagy-mediated physiological processes.
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Affiliation(s)
- Anthi Katsiarimpa
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising, Germany
| | - Kamila Kalinowska
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising, Germany
| | - Franziska Anzenberger
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising, Germany
| | - Corina Weis
- Department of Phytopathology, Technische Universität München, 85354 Freising, Germany
| | - Maya Ostertag
- Department of Phytopathology, Technische Universität München, 85354 Freising, Germany
| | - Chie Tsutsumi
- Department of Botany, National Museum of Nature and Science, Tsukuba 305-0005, Japan
| | - Claus Schwechheimer
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising, Germany
| | - Frédéric Brunner
- Department of Plant Biochemistry, Center for Plant Molecular Biology, Tübingen University, 72076 Tuebingen, Germany
| | - Ralph Hückelhoven
- Department of Phytopathology, Technische Universität München, 85354 Freising, Germany
| | - Erika Isono
- Department of Plant Systems Biology, Technische Universität München, 85354 Freising, Germany
- Address correspondence to
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68
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Yin X, Murphy SJ, Wilkes MC, Ji Y, Leof EB. Retromer maintains basolateral distribution of the type II TGF-β receptor via the recycling endosome. Mol Biol Cell 2013; 24:2285-98. [PMID: 23720763 PMCID: PMC3708733 DOI: 10.1091/mbc.e13-02-0093] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
After basolateral (BL) cell surface delivery, retromer promotes type II TGF-β receptor exit and recycling to the BL plasma membrane. In the absence of retromer, however, type II receptors aberrantly sort and are mislocalized such that both BL and apical expression is observed independent of the Rab11-positive apical recycling endosome. Transforming growth factor β (TGF-β) is critical for the development and maintenance of epithelial structures. Because receptor localization and trafficking affect the cellular and organismal response to TGF-β, the present study was designed to address how such homeostatic control is regulated. To that end, we identify a new role for the mammalian retromer complex in maintaining basolateral plasma membrane expression of the type II TGF-β receptor (TβRII). Retromer and TβRII associate in the presence or absence of TGF-β ligand. After retromer knockdown, although TβRII internalization and trafficking to a Rab5-positive compartment occur as in wild-type cells, receptor recycling is inhibited. This results in TβRII mislocalization from the basolateral to both the basolateral and apical plasma membranes independent of Golgi transit and the Rab11-positive apical recycling endosome. The data support a model in which, after initial basolateral TβRII delivery, steady-state polarized TβRII expression is maintained by retromer/TβRII binding and delivery to the common recycling endosome.
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Affiliation(s)
- Xueqian Yin
- Thoracic Disease Research Unit, Departments of Biochemistry/Molecular Biology and Medicine, Mayo Clinic Cancer Center, Rochester, MN 55905, USA
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69
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John Peter AT, Lachmann J, Rana M, Bunge M, Cabrera M, Ungermann C. The BLOC-1 complex promotes endosomal maturation by recruiting the Rab5 GTPase-activating protein Msb3. ACTA ACUST UNITED AC 2013; 201:97-111. [PMID: 23547030 PMCID: PMC3613695 DOI: 10.1083/jcb.201210038] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Yeast BLOC-1 acts as both a Rab5–Vps21 effector and an adapter for the Rab-GAP Msb3 to promote endosomal maturation. Membrane microcompartments of the early endosomes serve as a sorting and signaling platform, where receptors are either recycled back to the plasma membrane or forwarded to the lysosome for destruction. In metazoan cells, three complexes, termed BLOC-1 to -3, mediate protein sorting from the early endosome to lysosomes and lysosome-related organelles. We now demonstrate that BLOC-1 is an endosomal Rab-GAP (GTPase-activating protein) adapter complex in yeast. The yeast BLOC-1 consisted of six subunits, which localized interdependently to the endosomes in a Rab5/Vps21-dependent manner. In the absence of BLOC-1 subunits, the balance between recycling and degradation of selected cargoes was impaired. Additionally, our data show that BLOC-1 is both a Vps21 effector and an adapter for its GAP Msb3. BLOC-1 and Msb3 interacted in vivo, and both mutants resulted in a redistribution of active Vps21 to the vacuole surface. We thus conclude that BLOC-1 controls the lifetime of active Rab5/Vps21 and thus endosomal maturation along the endocytic pathway.
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Affiliation(s)
- Arun T John Peter
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, 49076 Osnabrück, Germany
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70
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The CORVET complex promotes tethering and fusion of Rab5/Vps21-positive membranes. Proc Natl Acad Sci U S A 2013; 110:3823-8. [PMID: 23417307 DOI: 10.1073/pnas.1221785110] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Membrane fusion along the endocytic pathway occurs in a sequence of tethering, docking, and fusion. At endosomes and vacuoles, the CORVET (class C core vacuole/endosome tethering) and HOPS (homotypic fusion and vacuole protein sorting) tethering complexes require their organelle-specific Rabs for localization and function. Until now, despite the absence of experimental evidence, it has been assumed that CORVET is a membrane-tethering factor. To test this theory and understand the mechanistic analogies with the HOPS complex, we set up an in vitro system, and establish CORVET as a bona-fide tether for Vps21-positive endosome/vacuole membranes. Purified CORVET binds to SNAREs and Rab5/Vps21-GTP. We then demonstrate that purified CORVET can specifically tether Vps21-positive membranes. Tethering via CORVET is dose-dependent, stimulated by the GEF Vps9, and inhibited by Msb3, the Vps21-GAP. Moreover, CORVET supports fusion of isolated membranes containing Vps21. In agreement with its role as a tether, overexpressed CORVET drives Vps21, but not the HOPS-specific Ypt7 into contact sites between vacuoles, which likely represent vacuole-associated endosomes. We therefore conclude that CORVET is a tethering complex that promotes fusion of Rab5-positive membranes and thus facilitates receptor down-regulation and recycling at the late endosome.
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71
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Vardarajan BN, Bruesegem SY, Harbour ME, St. George-Hyslop P, Seaman MN, Farrer LA. Identification of Alzheimer disease-associated variants in genes that regulate retromer function. Neurobiol Aging 2012; 33:2231.e15-2231.e30. [PMID: 22673115 PMCID: PMC3391348 DOI: 10.1016/j.neurobiolaging.2012.04.020] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 03/13/2012] [Accepted: 04/30/2012] [Indexed: 12/18/2022]
Abstract
The proteolytic processing of amyloid precursor protein (APP) to generate the neurotoxic amyloid β (Aβ) peptide is central to the pathogenesis of Alzheimer disease (AD). The endocytic system mediates the processing of APP by controlling its access to secretases that cleave APP. A key mediator of APP localization is SorL1-a membrane protein that has been genetically linked to AD. The retromer complex is a conserved protein complex required for endosome-to-Golgi retrieval of a number of physiologically important membrane proteins including SorL1. Based on the prior suggestion that endocytosis and retromer sorting pathways might be involved, we hypothesized that variants in other genes in this pathway might also modulate AD risk. Genetic association of AD with 451 polymorphisms in 15 genes encoding retromer or retromer-associated proteins was tested in a Caucasian sample of 8309 AD cases and 7366 cognitively normal elders using individual single nucleotide polymorphism (SNP)- and gene-based tests. We obtained significant evidence of association with KIAA1033 (VEGAS p = 0.025), SNX1 (VEGAS p = 0.035), SNX3 (p = 0.0057), and RAB7A (VEGAS p = 0.018). Ten KIAA1033 SNPs were also significantly associated with AD in a group of African Americans (513 AD cases, 504 control subjects). Findings with four significant SNX3 SNPs in the discovery sample were replicated in a community-based sample of Israeli-Arabs (124 AD cases, 142 control subjects). We show that Snx3 and Rab7A proteins interact with the cargo-selective retromer complex through independent mechanisms to regulate the membrane association of retromer and thereby are key mediators of retromer function. These data implicate additional AD risk genes in the retromer pathway and formally demonstrate a direct link between the activity of the retromer complex and the pathogenesis of AD.
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Affiliation(s)
- Badri N. Vardarajan
- Department of Medicine (Biomedical Genetics), Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118
| | - Sophia Y. Bruesegem
- University of Cambridge, Departments of Clinical Biochemistry and Clinical Neurosciences, Cambridge Institute for Medical Research, Addenbrookes Hospital, Cambridge, CB2 0XY, UK
| | - Michael E. Harbour
- University of Cambridge, Departments of Clinical Biochemistry and Clinical Neurosciences, Cambridge Institute for Medical Research, Addenbrookes Hospital, Cambridge, CB2 0XY, UK
| | - Peter St. George-Hyslop
- University of Cambridge, Departments of Clinical Biochemistry and Clinical Neurosciences, Cambridge Institute for Medical Research, Addenbrookes Hospital, Cambridge, CB2 0XY, UK
- Tanz Centre for Research in Neurodegenerative Diseases, Department of Medicine, University of Toronto, 1 King’s College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Matthew N.J. Seaman
- University of Cambridge, Departments of Clinical Biochemistry and Clinical Neurosciences, Cambridge Institute for Medical Research, Addenbrookes Hospital, Cambridge, CB2 0XY, UK
| | - Lindsay A. Farrer
- Department of Medicine (Biomedical Genetics), Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118
- Departments of Neurology, Ophthalmology, Genetics & Genomics, Epidemiology, and Biostatistics, Boston University Schools of Medicine and Public Health, 72 East Concord Street, Boston, MA 02118
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72
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Russell MRG, Shideler T, Nickerson DP, West M, Odorizzi G. Class E compartments form in response to ESCRT dysfunction in yeast due to hyperactivity of the Vps21 Rab GTPase. J Cell Sci 2012; 125:5208-20. [PMID: 22899724 DOI: 10.1242/jcs.111310] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The endosomal sorting complexes required for transport (ESCRTs) mediate the budding of intralumenal vesicles (ILVs) at late endosomes. ESCRT dysfunction causes drastic changes in endosome morphology, which are manifested in Saccharomyces cerevisiae by the formation of aberrant endosomes known as class E compartments. Except for the absence of ILVs, the mechanistic basis for class E compartment biogenesis is unknown. We used electron microscopy to examine endosomal morphology in response to transient ESCRT inactivation and recovery in yeast expressing the temperature-sensitive mutant vps4(ts) allele. Our results show class E compartments accumulate fourfold the amount of membrane normally present at multivesicular bodies and that multivesicular bodies can form directly from class E compartments upon recovery of ESCRT function. We found class E compartment formation requires Vps21, which is orthologous to the Rab5A GTPase in metazoans that promotes fusion of endocytic vesicles with early endosomes and homotypic fusion of early endosomes with one another. We also determined that class E compartments accumulate GTP-bound Vps21 and its effector, the class C core vacuole/endosome tethering (CORVET). Ypt7, the yeast ortholog of Rab7 that in metazoans promotes fusion of late endosomes with lysosomes, also accumulates at class E compartments but without its effector, the homotypic fusion and protein sorting (HOPS), signifying that Ypt7 at class E compartments is dysfunctional. These results suggest that failure to complete Rab5-Rab7 conversion is a consequence of ESCRT dysfunction, which results in Vps21 hyperactivity that drives the class E compartment morphology. Indeed, genetic disruption of Rab conversion without ESCRT dysfunction autonomously drives the class E compartment morphology without blocking ILV budding.
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Affiliation(s)
- Matthew R G Russell
- Department of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Campus Box 347, Boulder, CO 80309, USA
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73
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Dissecting the gene network of dietary restriction to identify evolutionarily conserved pathways and new functional genes. PLoS Genet 2012; 8:e1002834. [PMID: 22912585 PMCID: PMC3415404 DOI: 10.1371/journal.pgen.1002834] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 06/04/2012] [Indexed: 01/19/2023] Open
Abstract
Dietary restriction (DR), limiting nutrient intake from diet without causing malnutrition, delays the aging process and extends lifespan in multiple organisms. The conserved life-extending effect of DR suggests the involvement of fundamental mechanisms, although these remain a subject of debate. To help decipher the life-extending mechanisms of DR, we first compiled a list of genes that if genetically altered disrupt or prevent the life-extending effects of DR. We called these DR–essential genes and identified more than 100 in model organisms such as yeast, worms, flies, and mice. In order for other researchers to benefit from this first curated list of genes essential for DR, we established an online database called GenDR (http://genomics.senescence.info/diet/). To dissect the interactions of DR–essential genes and discover the underlying lifespan-extending mechanisms, we then used a variety of network and systems biology approaches to analyze the gene network of DR. We show that DR–essential genes are more conserved at the molecular level and have more molecular interactions than expected by chance. Furthermore, we employed a guilt-by-association method to predict novel DR–essential genes. In budding yeast, we predicted nine genes related to vacuolar functions; we show experimentally that mutations deleting eight of those genes prevent the life-extending effects of DR. Three of these mutants (OPT2, FRE6, and RCR2) had extended lifespan under ad libitum, indicating that the lack of further longevity under DR is not caused by a general compromise of fitness. These results demonstrate how network analyses of DR using GenDR can be used to make phenotypically relevant predictions. Moreover, gene-regulatory circuits reveal that the DR–induced transcriptional signature in yeast involves nutrient-sensing, stress responses and meiotic transcription factors. Finally, comparing the influence of gene expression changes during DR on the interactomes of multiple organisms led us to suggest that DR commonly suppresses translation, while stimulating an ancient reproduction-related process. Dietary restriction has been shown to extend lifespan in diverse, evolutionarily distant species, yet its underlying mechanisms remain unknown. We first constructed a database of genes essential for the life-extending effects of dietary restriction in various model organisms and then studied their interactions using a variety of network and systems biology approaches. This enabled us to predict novel genes related to dietary restriction, which we validated experimentally in yeast. By comparing large-scale data compilations (interactomes and transcriptomes) from multiple organisms, we were able to condense this -omics information to the most conserved essential elements, eliminating species-specific adaptive responses. These results lead us to the rather surprising conclusion that lifespan extension by a restricted diet commonly may exploit an ancient rejuvenation process derived from gametogenesis.
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Nickerson DP, Russell MRG, Lo SY, Chapin HC, Milnes J, Merz AJ. Termination of isoform-selective Vps21/Rab5 signaling at endolysosomal organelles by Msb3/Gyp3. Traffic 2012; 13:1411-1428. [PMID: 22748138 DOI: 10.1111/j.1600-0854.2012.01390.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 06/26/2012] [Accepted: 07/02/2012] [Indexed: 12/11/2022]
Abstract
Traffic through endosomes and lysosomes is controlled by small G-proteins of the Rab5 and Rab7 families. Like humans, Saccharomyces cerevisiae has three Rab5s (Vps21, Ypt52 and Ypt53) and one Rab7 (Ypt7). Here, we elucidate the functional roles and regulation of the yeast Rab5s. Using GFP-tagged cargoes, a novel quantitative multivesicular body (MVB) sorting assay, and electron microscopy, we show that MVB biogenesis and thus MVB cargo sorting is severely impaired in vps21Δ ypt52Δ double mutants. Ypt53, the third Rab5 paralog, is hardly expressed during normal growth but its transcription is strongly induced by cellular stress through the calcineurin-Crz1 pathway. The requirement for Rab5 activity in stress tolerance facilitated identification of Msb3/Gyp3 as the principal Rab5 GAP (GTPase accelerating protein). In vitro GAP assays verified that Vps21 is a preferred Gyp3 target. Moreover, we demonstrate that Gyp3 spatially restricts active Vps21 to intermediate endosomal compartments by preventing Vps21 accumulation on lysosomal vacuoles. Gyp3, therefore, operates as a compartmental insulator that helps to define the spatial domain of Vps21 signaling in the endolysosomal pathway.
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Affiliation(s)
- Daniel P Nickerson
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Matthew R G Russell
- Department of Molecular, Cell and Developmental Biology University of Colorado, Boulder CO 80309-0347
| | - Shing-Yeng Lo
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Hannah C Chapin
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Joshua Milnes
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Alexey J Merz
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
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75
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Robinson DG, Pimpl P, Scheuring D, Stierhof YD, Sturm S, Viotti C. Trying to make sense of retromer. TRENDS IN PLANT SCIENCE 2012; 17:431-9. [PMID: 22502774 DOI: 10.1016/j.tplants.2012.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/13/2012] [Accepted: 03/15/2012] [Indexed: 05/08/2023]
Abstract
Retromer is a cytosolic protein complex which binds to post-Golgi organelles involved in the trafficking of proteins to the lytic compartment of the cell. In non-plant organisms, retromer mediates the recycling of acid hydrolase receptors from early endosomal (EE) compartments. In plants, retromer components are required for the targeting of vacuolar storage proteins, and for the recycling of endocytosed PIN proteins. However, there are contradictory reports as to the localization of the sorting nexins and the core subunit of retromer. There is also uncertainty as to the identity of the organelles from which vacuolar sorting receptors (VSRs) and endocytosed plasma membrane (PM) proteins are recycled. In this review we try to resolve some of these conflicting observations.
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Affiliation(s)
- David G Robinson
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, D-69120 Heidelberg, Germany.
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76
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Liu TT, Gomez TS, Sackey BK, Billadeau DD, Burd CG. Rab GTPase regulation of retromer-mediated cargo export during endosome maturation. Mol Biol Cell 2012; 23:2505-15. [PMID: 22593205 PMCID: PMC3386214 DOI: 10.1091/mbc.e11-11-0915] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 04/25/2012] [Accepted: 05/07/2012] [Indexed: 11/11/2022] Open
Abstract
The retromer complex, composed of sorting nexin subunits and a Vps26/Vps29/Vps35 trimer, mediates sorting of retrograde cargo from the endosome to the trans-Golgi network. The retromer trimer subcomplex is an effector of Rab7 (Ypt7 in yeast). Whereas endosome targeting of human retromer has been shown to require Rab7-GTP, targeting of yeast retromer to the endosome is independent of Ypt7-GTP and requires the Vps5 and Vps17 retromer sorting nexin subunits. An evolutionarily conserved amino acid segment within Vps35 is required for Ypt7/Rab7 recognition in vivo by both yeast and human retromer, establishing that Rab recognition is a conserved feature of this subunit. Recognition of Ypt7 by retromer is required for its function in retrograde sorting, and in yeast cells lacking the guanine nucleotide exchange factor for Ypt7, retrograde cargo accumulates in endosomes that are decorated with retromer, revealing an additional role for Rab recognition at the cargo export stage of the retromer functional cycle. In addition, yeast retromer trimer antagonizes Ypt7-regulated organelle tethering and fusion of endosomes/vacuoles via recognition of Ypt7. Thus retromer has dual roles in retrograde cargo export and in controlling the fusion dynamics of the late endovacuolar system.
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Affiliation(s)
- Ting-Ting Liu
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Timothy S. Gomez
- Department of Immunology, Division of Oncology Research and Schulze Center for Novel Therapeutics, College of Medicine, Mayo Clinic, Rochester, MN 55905
| | - Bridget K. Sackey
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel D. Billadeau
- Department of Immunology, Division of Oncology Research and Schulze Center for Novel Therapeutics, College of Medicine, Mayo Clinic, Rochester, MN 55905
| | - Christopher G. Burd
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
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77
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Abenza JF, Galindo A, Pinar M, Pantazopoulou A, de los Ríos V, Peñalva MA. Endosomal maturation by Rab conversion in Aspergillus nidulans is coupled to dynein-mediated basipetal movement. Mol Biol Cell 2012; 23:1889-901. [PMID: 22456509 PMCID: PMC3350553 DOI: 10.1091/mbc.e11-11-0925] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Highly motile fungal early endosomes can be easily distinguished from more static late endosomes and vacuoles, a feature that is exploited to study endosomal maturation. RabA/RabB early endosomes mature into RabSRab7 late endosomes as they move away from the tip where endocytosis predominates, augmenting their size, with concomitant loss of motility. We exploit the ease with which highly motile early endosomes are distinguished from static late endosomes in order to study Aspergillus nidulans endosomal traffic. RabSRab7 mediates homotypic fusion of late endosomes/vacuoles in a homotypic fusion- and vacuole protein sorting/Vps41–dependent manner. Progression across the endocytic pathway involves endosomal maturation because the end products of the pathway in the absence of RabSRab7 are minivacuoles that are competent in multivesicular body sorting and cargo degradation but retain early endosomal features, such as the ability to undergo long-distance movement and propensity to accumulate in the tip region if dynein function is impaired. Without RabSRab7, early endosomal Rab5s—RabA and RabB—reach minivacuoles, in agreement with the view that Rab7 homologues facilitate the release of Rab5 homologues from endosomes. RabSRab7 is recruited to membranes already at the stage of late endosomes still lacking vacuolar morphology, but the transition between early and late endosomes is sharp, as only in a minor proportion of examples are RabA/RabB and RabSRab7 detectable in the same—frequently the less motile—structures. This early-to-late endosome/vacuole transition is coupled to dynein-dependent movement away from the tip, resembling the periphery-to-center traffic of endosomes accompanying mammalian cell endosomal maturation. Genetic studies establish that endosomal maturation is essential, whereas homotypic vacuolar fusion is not.
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Affiliation(s)
- Juan F Abenza
- Departamento de Medicina Molecular y Celular, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Cientificas, 28040 Madrid, Spain
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78
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Cullen PJ, Korswagen HC. Sorting nexins provide diversity for retromer-dependent trafficking events. Nat Cell Biol 2011; 14:29-37. [PMID: 22193161 PMCID: PMC3613977 DOI: 10.1038/ncb2374] [Citation(s) in RCA: 260] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sorting nexins are a large family of evolutionarily conserved phosphoinositide-binding proteins that have fundamental roles in orchestrating cargo sorting through the membranous maze that is the endosomal network. One ancient group of complexes that contain sorting nexins is the retromer. Here we discuss how retromer complexes regulate endosomal sorting, and describe how this is generating exciting new insight into the central role played by endosomal sorting in development and homeostasis of normal tissues.
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Affiliation(s)
- Peter J. Cullen
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, U.K
| | - Hendrik C. Korswagen
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
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79
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Kallay LM, Brett CL, Tukaye DN, Wemmer MA, Chyou A, Odorizzi G, Rao R. Endosomal Na+ (K+)/H+ exchanger Nhx1/Vps44 functions independently and downstream of multivesicular body formation. J Biol Chem 2011; 286:44067-44077. [PMID: 21998311 DOI: 10.1074/jbc.m111.282319] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The multivesicular body (MVB) is an endosomal intermediate containing intralumenal vesicles destined for membrane protein degradation in the lysosome. In Saccharomyces cerevisiae, the MVB pathway is composed of 17 evolutionarily conserved ESCRT (endosomal sorting complex required for transport) genes grouped by their vacuole protein sorting Class E mutant phenotypes. Only one integral membrane protein, the endosomal Na+ (K+)/H+ exchanger Nhx1/Vps44, has been assigned to this class, but its role in the MVB pathway has not been directly tested. Herein, we first evaluated the link between Nhx1 and the ESCRT proteins and then used an unbiased phenomics approach to probe the cellular role of Nhx1. Select ESCRT mutants (vps36Δ, vps20Δ, snf7Δ, and bro1Δ) with defects in cargo packaging and intralumenal vesicle formation shared multiple growth phenotypes with nhx1Δ. However, analysis of cellular trafficking and ultrastructural examination by electron microscopy revealed that nhx1Δ cells retain the ability to sort cargo into intralumenal vesicles. In addition, we excluded a role for Nhx1 in Snf7/Bro1-mediated cargo deubiquitylation and Rim101 response to pH stress. Genetic epistasis experiments provided evidence that NHX1 and ESCRT genes function in parallel. A genome-wide screen for single gene deletion mutants that phenocopy nhx1Δ yielded a limited gene set enriched for endosome fusion function, including Rab signaling and actin cytoskeleton reorganization. In light of these findings and the absence of the so-called Class E compartment in nhx1Δ, we eliminated a requirement for Nhx1 in MVB formation and suggest an alternative post-ESCRT role in endosomal membrane fusion.
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Affiliation(s)
- Laura M Kallay
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Christopher L Brett
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Biology, Concordia University, Montréal, Quebec H3G 1M8, Canada
| | - Deepali N Tukaye
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Megan A Wemmer
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Anthony Chyou
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Greg Odorizzi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Rajini Rao
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
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Epp N, Rethmeier R, Krämer L, Ungermann C. Membrane dynamics and fusion at late endosomes and vacuoles – Rab regulation, multisubunit tethering complexes and SNAREs. Eur J Cell Biol 2011; 90:779-85. [DOI: 10.1016/j.ejcb.2011.04.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Arlt H, Perz A, Ungermann C. An Overexpression Screen in Saccharomyces cerevisiae Identifies Novel Genes that Affect Endocytic Protein Trafficking. Traffic 2011; 12:1592-603. [DOI: 10.1111/j.1600-0854.2011.01252.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cabrera M, Langemeyer L, Mari M, Rethmeier R, Orban I, Perz A, Bröcker C, Griffith J, Klose D, Steinhoff HJ, Reggiori F, Engelbrecht-Vandré S, Ungermann C. Phosphorylation of a membrane curvature-sensing motif switches function of the HOPS subunit Vps41 in membrane tethering. ACTA ACUST UNITED AC 2011; 191:845-59. [PMID: 21079247 PMCID: PMC2983053 DOI: 10.1083/jcb.201004092] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An AP-3–binding site required for vesicle–vacuole fusion is masked when Vps41 is associated with highly curved membranes, such as endosomes, but is exposed at membranes with lower curvature, such as vacuoles, because of phosphorylation of the membrane-binding motif. Tethering factors are organelle-specific multisubunit protein complexes that identify, along with Rab guanosine triphosphatases, transport vesicles and trigger their SNARE-mediated fusion of specific transport vesicles with the target membranes. Little is known about how tethering factors discriminate between different trafficking pathways, which may converge at the same organelle. In this paper, we describe a phosphorylation-based switch mechanism, which allows the homotypic vacuole fusion protein sorting effector subunit Vps41 to operate in two distinct fusion events, namely endosome–vacuole and AP-3 vesicle–vacuole fusion. Vps41 contains an amphipathic lipid-packing sensor (ALPS) motif, which recognizes highly curved membranes. At endosomes, this motif is inserted into the lipid bilayer and masks the binding motif for the δ subunit of the AP-3 complex, Apl5, without affecting the Vps41 function in endosome–vacuole fusion. At the much less curved vacuole, the ALPS motif becomes available for phosphorylation by the resident casein kinase Yck3. As a result, the Apl5-binding site is exposed and allows AP-3 vesicles to bind to Vps41, followed by specific fusion with the vacuolar membrane. This multifunctional tethering factor thus discriminates between trafficking routes by switching from a curvature-sensing to a coat recognition mode upon phosphorylation.
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Affiliation(s)
- Margarita Cabrera
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, 49076 Osnabrück, Germany
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