1
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Fote GM, Eapen VV, Lim RG, Yu C, Salazar L, McClure NR, McKnight J, Nguyen TB, Heath MC, Lau AL, Villamil MA, Miramontes R, Kratter IH, Finkbeiner S, Reidling JC, Paulo JA, Kaiser P, Huang L, Housman DE, Thompson LM, Steffan JS. Huntingtin contains an ubiquitin-binding domain and regulates lysosomal targeting of mitochondrial and RNA-binding proteins. Proc Natl Acad Sci U S A 2024; 121:e2319091121. [PMID: 39074279 PMCID: PMC11317567 DOI: 10.1073/pnas.2319091121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 06/20/2024] [Indexed: 07/31/2024] Open
Abstract
Understanding the normal function of the Huntingtin (HTT) protein is of significance in the design and implementation of therapeutic strategies for Huntington's disease (HD). Expansion of the CAG repeat in the HTT gene, encoding an expanded polyglutamine (polyQ) repeat within the HTT protein, causes HD and may compromise HTT's normal activity contributing to HD pathology. Here, we investigated the previously defined role of HTT in autophagy specifically through studying HTT's association with ubiquitin. We find that HTT interacts directly with ubiquitin in vitro. Tandem affinity purification was used to identify ubiquitinated and ubiquitin-associated proteins that copurify with a HTT N-terminal fragment under basal conditions. Copurification is enhanced by HTT polyQ expansion and reduced by mimicking HTT serine 421 phosphorylation. The identified HTT-interacting proteins include RNA-binding proteins (RBPs) involved in mRNA translation, proteins enriched in stress granules, the nuclear proteome, the defective ribosomal products (DRiPs) proteome and the brain-derived autophagosomal proteome. To determine whether the proteins interacting with HTT are autophagic targets, HTT knockout (KO) cells and immunoprecipitation of lysosomes were used to investigate autophagy in the absence of HTT. HTT KO was associated with reduced abundance of mitochondrial proteins in the lysosome, indicating a potential compromise in basal mitophagy, and increased lysosomal abundance of RBPs which may result from compensatory up-regulation of starvation-induced macroautophagy. We suggest HTT is critical for appropriate basal clearance of mitochondrial proteins and RBPs, hence reduced HTT proteostatic function with mutation may contribute to the neuropathology of HD.
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Affiliation(s)
- Gianna M. Fote
- Department of Biological Chemistry, UC Irvine School of Medicine, Irvine, CA92697
- Department of Neurological Surgery, UC Irvine School of Medicine, Orange, CA92868
| | - Vinay V. Eapen
- Department of Cell Biology, Harvard Medical School, Boston, MA02115
- Casma Therapeutics, Cambridge, MA02139
| | - Ryan G. Lim
- The University of California Irvine Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA92697
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, CA92697
| | - Lisa Salazar
- Department of Psychiatry and Human Behavior, UC Irvine School of Medicine, Orange, CA92868
| | - Nicolette R. McClure
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
| | - Jharrayne McKnight
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
| | - Thai B. Nguyen
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
| | - Marie C. Heath
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
| | - Alice L. Lau
- Department of Psychiatry and Human Behavior, UC Irvine School of Medicine, Orange, CA92868
| | - Mark A. Villamil
- Department of Biological Chemistry, UC Irvine School of Medicine, Irvine, CA92697
| | - Ricardo Miramontes
- Department of Psychiatry and Human Behavior, UC Irvine School of Medicine, Orange, CA92868
| | - Ian H. Kratter
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA94158
- Stanford Brain Stimulation Lab, Stanford, CA94304
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA94304
| | - Steven Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA94158
- Department of Physiology, University of California, San Francisco, CA94158
- Department of Neurology, University of California, San Francisco, CA94158
| | - Jack C. Reidling
- The University of California Irvine Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA92697
| | - Joao A. Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA02115
| | - Peter Kaiser
- Department of Biological Chemistry, UC Irvine School of Medicine, Irvine, CA92697
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, CA92697
| | - David E. Housman
- Koch Institute for Integrative Cancer Research, The Massachusetts Institute of Technology, Cambridge, MA02139
| | - Leslie M. Thompson
- Department of Biological Chemistry, UC Irvine School of Medicine, Irvine, CA92697
- The University of California Irvine Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA92697
- Department of Psychiatry and Human Behavior, UC Irvine School of Medicine, Orange, CA92868
- Department of Neurobiology and Behavior, University of California, Irvine, CA92697
- Center for Epigenetics and Metabolism, University of California, Irvine School of Medicine, University of California, Irvine, CA92697
| | - Joan S. Steffan
- The University of California Irvine Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA92697
- Department of Psychiatry and Human Behavior, UC Irvine School of Medicine, Orange, CA92868
- Center for Epigenetics and Metabolism, University of California, Irvine School of Medicine, University of California, Irvine, CA92697
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2
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Tseng CC, Dean S, Davies BA, Azmi IF, Pashkova N, Payne JA, Staffenhagen J, West M, Piper RC, Odorizzi G, Katzmann DJ. Bro1 stimulates Vps4 to promote intralumenal vesicle formation during multivesicular body biogenesis. J Cell Biol 2021; 220:212434. [PMID: 34160559 PMCID: PMC8240856 DOI: 10.1083/jcb.202102070] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/18/2021] [Accepted: 05/23/2021] [Indexed: 01/20/2023] Open
Abstract
Endosomal sorting complexes required for transport (ESCRT-0, -I, -II, -III) execute cargo sorting and intralumenal vesicle (ILV) formation during conversion of endosomes to multivesicular bodies (MVBs). The AAA-ATPase Vps4 regulates the ESCRT-III polymer to facilitate membrane remodeling and ILV scission during MVB biogenesis. Here, we show that the conserved V domain of ESCRT-associated protein Bro1 (the yeast homologue of mammalian proteins ALIX and HD-PTP) directly stimulates Vps4. This activity is required for MVB cargo sorting. Furthermore, the Bro1 V domain alone supports Vps4/ESCRT–driven ILV formation in vivo without efficient MVB cargo sorting. These results reveal a novel activity of the V domains of Bro1 homologues in licensing ESCRT-III–dependent ILV formation and suggest a role in coordinating cargo sorting with membrane remodeling during MVB sorting. Moreover, ubiquitin binding enhances V domain stimulation of Vps4 to promote ILV formation via the Bro1–Vps4–ESCRT-III axis, uncovering a novel role for ubiquitin during MVB biogenesis in addition to facilitating cargo recognition.
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Affiliation(s)
- Chun-Che Tseng
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN.,Biochemistry and Molecular Biology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN
| | - Shirley Dean
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN.,Biochemistry and Molecular Biology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN
| | - Brian A Davies
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN
| | - Ishara F Azmi
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN.,Biochemistry and Molecular Biology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN
| | - Natalya Pashkova
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Johanna A Payne
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN
| | | | - Matt West
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO
| | - Robert C Piper
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Greg Odorizzi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO
| | - David J Katzmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN.,Biochemistry and Molecular Biology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN
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3
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Liao PC, Wolken DMA, Serrano E, Srivastava P, Pon LA. Mitochondria-Associated Degradation Pathway (MAD) Function beyond the Outer Membrane. Cell Rep 2021; 32:107902. [PMID: 32668258 PMCID: PMC7391283 DOI: 10.1016/j.celrep.2020.107902] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/07/2020] [Accepted: 06/23/2020] [Indexed: 12/01/2022] Open
Abstract
The mitochondria-associated degradation pathway (MAD) mediates ubiquitination and degradation of mitochondrial outer membrane (MOM) proteins by the proteasome. We find that the MAD, but not other quality-control pathways including macroautophagy, mitophagy, or mitochondrial chaperones and proteases, is critical for yeast cellular fitness under conditions of paraquat (PQ)-induced oxidative stress in mitochondria. Specifically, inhibition of the MAD increases PQ-induced defects in growth and mitochondrial quality and decreases chronological lifespan. We use mass spectrometry analysis to identify possible MAD substrates as mitochondrial proteins that exhibit increased ubiquitination in response to PQ treatment and inhibition of the MAD. We identify candidate substrates in the mitochondrial matrix and inner membrane and confirm that two matrix proteins are MAD substrates. Our studies reveal a broader function for the MAD in mitochondrial protein surveillance beyond the MOM and a major role for the MAD in cellular and mitochondrial fitness in response to chronic, low-level oxidative stress in mitochondria.
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Affiliation(s)
- Pin-Chao Liao
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | | | - Edith Serrano
- Department of Chemistry, Barnard College, Columbia University, New York, NY 10027, USA
| | - Pallavi Srivastava
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G1H9, Canada
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
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4
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Reichert P, Caudron F. Mnemons and the memorization of past signaling events. Curr Opin Cell Biol 2021; 69:127-135. [PMID: 33618243 DOI: 10.1016/j.ceb.2021.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 11/28/2022]
Abstract
Current advances are raising our awareness of the diverse roles that protein condensation plays in the biology of cells. Particularly, findings in organisms as diverse as yeast and Drosophila suggest that cells may utilize protein condensation to establish long-lasting changes in cellular activities and thereby encode a memory of past signaling events. Proteins that oligomerize to confer such cellular memory have been termed 'mnemons'. In the forming of super-assemblies, mnemons change their function and modulate the influence that the affected protein originally had on cellular processes. Because mnemon assemblies are self-templating, they allow cells to retain the memory of past decisions over larger timescales. Here, we review the mechanisms behind the formation of cellular memory with an emphasis on mnemon-mediated memorization of past signaling events.
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Affiliation(s)
- Polina Reichert
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Fabrice Caudron
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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5
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de Souza W, Barrias ES. Membrane-bound extracellular vesicles secreted by parasitic protozoa: cellular structures involved in the communication between cells. Parasitol Res 2020; 119:2005-2023. [PMID: 32394001 DOI: 10.1007/s00436-020-06691-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/15/2020] [Indexed: 02/06/2023]
Abstract
The focus of this review is a group of structures/organelles collectively known as extracellular vesicles (EVs) that are secreted by most, if not all, cells, varying from mammalian cells to protozoa and even bacteria. They vary in size: some are small (100-200 nm) and others are larger (> 200 nm). In protozoa, however, most of them are small or medium in size (200-400 nm). These include vesicles from different origins. We briefly review the biogenesis of this distinct group that includes (a) exosome, which originates from the multivesicular bodies, an important component of the endocytic pathway; (b) ectosome, formed from a budding process that takes place in the plasma membrane of the cells; (c) vesicles released from the cell surface following a process of patching and capping of ligand/receptor complexes; (d) other processes where tubules secreted by the parasite subsequently originate exosome-like structures. Here, special emphasis is given to EVs secreted by parasitic protozoa such as Leishmania, Trypanosoma, Plasmodium, Toxoplasma, Cryptosporidium, Trichomonas, and Giardia. Most of them have been characterized as exosomes that were isolated using several approaches and characterized by electron microscopy, proteomic analysis, and RNA sequencing. The results obtained show clearly that they present several proteins and different types of RNAs. From the functional point of view, it is now clear that the secreted exosomes can be incorporated by the parasite itself as well as by mammalian cells with which they interact. As a consequence, there is interference both with the parasite (induction of differentiation, changes in infectivity, etc.) and with the host cell. Therefore, the EVs constitute a new system of transference of signals among cells. On the other hand, there are suggestions that exosomes may constitute potential biotechnology tools and are important players of what has been designated as nanobiotechnology. They may constitute an important delivery system for gene therapy and molecular-displaying cell regulation capabilities when incorporated into other cells and even by interfering with the exosomal membrane during its biogenesis, targeting the vesicles via specific ligands to different cell types. These vesicles may reach the bloodstream, overflow through intercellular junctions, and even pass through the central nervous system blood barrier. There is evidence that it is possible to interfere with the composition of the exosomes by interfering with multivesicular body biogenesis.
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Affiliation(s)
- Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Bloco G, Ilha do Fundão, Rio de Janeiro, RJ, 21941-900, Brazil. .,Instituto Nacional de Ciência e Tecnologia and Núcleo de Biologia Estrutural e Bioimagens, CENABIO, Rio de Janeiro, Brazil.
| | - Emile S Barrias
- Instituto Nacional de Ciência e Tecnologia and Núcleo de Biologia Estrutural e Bioimagens, CENABIO, Rio de Janeiro, Brazil.,Laboratorio de Metrologia Aplicada à Ciências da Vida, Diretoria de Metrologia Aplicada à Ciências da Vida - Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro), Rio de Janeiro, Brazil
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6
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Yanguas F, Moscoso-Romero E, Valdivieso MH. Ent3 and GGA adaptors facilitate diverse anterograde and retrograde trafficking events to and from the prevacuolar endosome. Sci Rep 2019; 9:10747. [PMID: 31341193 PMCID: PMC6656748 DOI: 10.1038/s41598-019-47035-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/09/2019] [Indexed: 11/09/2022] Open
Abstract
Carboxypeptidases Y (Cpy1) and S (Cps1), the receptor Vps10, and the ATPase subunit Vph1 follow the carboxypeptidase Y (CPY) pathway from the trans-Golgi network (TGN) to the prevacuolar endosome (PVE). Using Schizosaccharomyces pombe quantitative live-cell imaging, biochemical and genetic analyses, we extended the previous knowledge and showed that collaboration between Gga22, the dominant Golgi-localized Gamma-ear-containing ARF-binding (GGA) protein, and Gga21, and between Gga22 and the endosomal epsin Ent3, was required for efficient: i) Vps10 anterograde trafficking from the TGN to the PVE; ii) Vps10 retrograde trafficking from the PVE to the TGN; iii) Cps1 exit from the TGN, and its sorting in the PVE en route to the vacuole; and iv) Syb1/Snc1 recycling to the plasma membrane through the PVE. Therefore, monomeric clathrin adaptors facilitated the trafficking of Vps10 in both directions of the CPY pathway, and facilitated trafficking events of Cps1 in different organelles. By contrast, they were dispensable for Vph1 trafficking. Thus, these adaptors regulated the traffic of some, but not all, of the cargo of the CPY pathway, and regulated the traffic of cargoes that do not follow this pathway. Additionally, this collaboration was required for PVE organization and efficient growth under stress.
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Affiliation(s)
- Francisco Yanguas
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - Esteban Moscoso-Romero
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain
| | - M-Henar Valdivieso
- Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain. .,Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), Calle Zacarías González 2, 37007, Salamanca, Spain.
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7
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Ma M, Burd CG. Retrograde trafficking and quality control of yeast synaptobrevin, Snc1, are conferred by its transmembrane domain. Mol Biol Cell 2019; 30:1729-1742. [PMID: 31067149 PMCID: PMC6727757 DOI: 10.1091/mbc.e19-02-0117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/11/2019] [Accepted: 05/03/2019] [Indexed: 11/11/2022] Open
Abstract
Synaptobrevin/vesicle-associated membrane protein 2 (VAMP2) is an essential soluble N-ethyl maleimide-sensitive factor attachment protein receptor (SNARE) protein that has been extensively studied in its role in synaptic vesicle fusion. However, sorting and trafficking of VAMP2 within the endosomal system is not well understood. Here, we use the yeast VAMP2 homologue Snc1 to investigate the pathways and signals required for endocytic trafficking. We identify two genetically distinct retrieval pathways from the endosomal system: a plasma membrane recycling pathway that requires the Rcy1 F-box protein and a retrograde pathway originating from the multivesicular/prevacuole endosome dependent on the Snx4-Atg20 sorting nexin complex. Lysine residues within the transmembrane domain of Snc1 are necessary for presentation of a Snx4-Atg20-dependent sorting signal located within its juxtamembrane region. Mutations of the transmembrane lysine residues ablate retrograde sorting and subject Snc1 to quality control via sorting into the degradative multivesicular endosome pathway. Degradative sorting requires lysine residues in the juxtamembrane region of Snc1 and is mediated by the Rsp5 ubiquitin ligase and its transmembrane adapters, Ear1 and Ssh4, which localize to endosome and vacuole membranes. This study shows that Snc1 is trafficked between the endosomal system and the Golgi apparatus via multiple pathways and provides evidence for protein quality control surveillance of a SNARE protein in the endo-vacuolar system.
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Affiliation(s)
- Mengxiao Ma
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
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8
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Aufschnaiter A, Büttner S. The vacuolar shapes of ageing: From function to morphology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:957-970. [PMID: 30796938 DOI: 10.1016/j.bbamcr.2019.02.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 12/21/2022]
Abstract
Cellular ageing results in accumulating damage to various macromolecules and the progressive decline of organelle function. Yeast vacuoles as well as their counterpart in higher eukaryotes, the lysosomes, emerge as central organelles in lifespan determination. These acidic organelles integrate enzymatic breakdown and recycling of cellular waste with nutrient sensing, storage, signalling and mobilization. Establishing physical contact with virtually all other organelles, vacuoles serve as hubs of cellular homeostasis. Studies in Saccharomyces cerevisiae contributed substantially to our understanding of the ageing process per se and the multifaceted roles of vacuoles/lysosomes in the maintenance of cellular fitness with progressing age. Here, we discuss the multiple roles of the vacuole during ageing, ranging from vacuolar dynamics and acidification as determinants of lifespan to the function of this organelle as waste bin, recycling facility, nutrient reservoir and integrator of nutrient signalling.
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Affiliation(s)
- Andreas Aufschnaiter
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria
| | - Sabrina Büttner
- Institute of Molecular Biosciences, University of Graz, Humboldtstraße 50, 8010 Graz, Austria; Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, 106 91 Stockholm, Sweden.
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9
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Weill U, Arakel EC, Goldmann O, Golan M, Chuartzman S, Munro S, Schwappach B, Schuldiner M. Toolbox: Creating a systematic database of secretory pathway proteins uncovers new cargo for COPI. Traffic 2019. [PMID: 29527758 PMCID: PMC5947560 DOI: 10.1111/tra.12560] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A third of yeast genes encode for proteins that function in the endomembrane system. However, the precise localization for many of these proteins is still uncertain. Here, we visualized a collection of ~500 N‐terminally, green fluorescent protein (GFP), tagged proteins of the yeast Saccharomyces cerevisiae. By co‐localizing them with 7 known markers of endomembrane compartments we determined the localization for over 200 of them. Using this approach, we create a systematic database of the various secretory compartments and identify several new residents. Focusing in, we now suggest that Lam5 resides in contact sites between the endoplasmic reticulum and the late Golgi. Additionally, analysis of interactions between the COPI coat and co‐localizing proteins from our screen identifies a subset of proteins that are COPI‐cargo. In summary, our approach defines the protein roster within each compartment enabling characterization of the physical and functional organization of the endomembrane system and its components.
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Affiliation(s)
- Uri Weill
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eric C Arakel
- Universitätsmedizin Göttingen Institut für Molekularbiologie Humboldtallee 23, D-37073 Göttingen, Germany
| | - Omer Goldmann
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Matan Golan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Silvia Chuartzman
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Blanche Schwappach
- Universitätsmedizin Göttingen Institut für Molekularbiologie Humboldtallee 23, D-37073 Göttingen, Germany.,Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
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10
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Carpinone EM, Li Z, Mills MK, Foltz C, Brannon ER, Carlow CKS, Starai VJ. Identification of putative effectors of the Type IV secretion system from the Wolbachia endosymbiont of Brugia malayi. PLoS One 2018; 13:e0204736. [PMID: 30261054 PMCID: PMC6160203 DOI: 10.1371/journal.pone.0204736] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 09/13/2018] [Indexed: 11/19/2022] Open
Abstract
Wolbachia is an unculturable, intracellular bacterium that persists within an extremely broad range of arthropod and parasitic nematode hosts, where it is transmitted maternally to offspring via vertical transmission. In the filarial nematode Brugia malayi, a causative agent of human lymphatic filariasis, Wolbachia is an endosymbiont, and its presence is essential for proper nematode development, survival, and pathogenesis. While the elucidation of Wolbachia:nematode interactions that promote the bacterium’s intracellular persistence is of great importance, research has been hampered due to the fact that Wolbachia cannot be cultured in the absence of host cells. The Wolbachia endosymbiont of B. malayi (wBm) has an active Type IV secretion system (T4SS). Here, we have screened 47 putative T4SS effector proteins of wBm for their ability to modulate growth or the cell biology of a typical eukaryotic cell, Saccharomyces cerevisiae. Five candidates strongly inhibited yeast growth upon expression, and 6 additional proteins showed toxicity in the presence of zinc and caffeine. Studies on the uptake of an endocytic vacuole-specific fluorescent marker, FM4-64, identified 4 proteins (wBm0076 wBm00114, wBm0447 and wBm0152) involved in vacuole membrane dynamics. The WAS(p)-family protein, wBm0076, was found to colocalize with yeast cortical actin patches and disrupted actin cytoskeleton dynamics upon expression. Deletion of the Arp2/3-activating protein, Abp1p, provided resistance to wBm0076 expression, suggesting a role for wBm0076 in regulating eukaryotic actin dynamics and cortical actin patch formation. Furthermore, wBm0152 was found to strongly disrupt endosome:vacuole cargo trafficking in yeast. This study provides molecular insight into the potential role of the T4SS in the Wolbachia endosymbiont:nematode relationship.
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Affiliation(s)
- Emily M. Carpinone
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
| | - Zhiru Li
- Division of Genome Biology, New England Biolabs, Ipswich, MA, United States of America
| | - Michael K. Mills
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
| | - Clemence Foltz
- Division of Genome Biology, New England Biolabs, Ipswich, MA, United States of America
| | - Emma R. Brannon
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
| | - Clotilde K. S. Carlow
- Division of Genome Biology, New England Biolabs, Ipswich, MA, United States of America
| | - Vincent J. Starai
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
- Department of Infectious Diseases, University of Georgia, Athens, GA, United States of America
- * E-mail:
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11
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McColl AI, Bleackley MR, Anderson MA, Lowe RGT. Resistance to the Plant Defensin NaD1 Features Modifications to the Cell Wall and Osmo-Regulation Pathways of Yeast. Front Microbiol 2018; 9:1648. [PMID: 30087664 PMCID: PMC6066574 DOI: 10.3389/fmicb.2018.01648] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/02/2018] [Indexed: 11/24/2022] Open
Abstract
Over the last few decades, the emergence of resistance to commonly used antifungal molecules has become a major barrier to effective treatment of recurrent life-threatening fungal diseases. Resistance combined with the increased incidence of fungal diseases has created the need for new antifungals, such as the plant defensin NaD1, with different mechanisms of action to broaden treatment options. Antimicrobial peptides produced in plants and animals are promising new molecules in the arsenal of antifungal agents because they have different mechanisms of action to current antifungals and are often targeted specifically to fungal pathogens (van der Weerden et al., 2013). A key step in the development of novel antifungals is an understanding of the potential for the fungus to develop resistance. Here, we have used the prototypic plant defensin NaD1 in serial passages with the model fungus Saccharomyces cerevisiae to examine the evolution of resistance to plant antifungal peptides. The yeast strains did develop tolerance to NaD1, but it occurred more slowly than to the clinically used antifungal caspofungin. Sequencing the genomes of the strains with increased tolerance failed to identify any ‘hotspot’ mutations associated with increased tolerance to NaD1 and led to the identification of 12 genes that are involved in resistance. Characterization of the strains with increased tolerance to NaD1 also revealed changes in tolerance to abiotic stressors. Resistance developed slowly via an accumulation of single nucleotide mutations and had a fitness penalty associated with it. One of the genes identified FPS1, revealed that there is a common mechanism of resistance to NaD1 that involves the osmotic stress response pathway. These data indicate that it is more difficult to generate resistance to antimicrobial peptides such as NaD1 compared to small molecule antifungals.
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Affiliation(s)
- Amanda I McColl
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Mark R Bleackley
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Marilyn A Anderson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Rohan G T Lowe
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
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12
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Kama R, Gabriely G, Kanneganti V, Gerst JE. Cdc48 and ubiquilins confer selective anterograde protein sorting and entry into the multivesicular body in yeast. Mol Biol Cell 2018; 29:948-963. [PMID: 29444958 PMCID: PMC5896933 DOI: 10.1091/mbc.e17-11-0652] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/22/2018] [Accepted: 02/07/2018] [Indexed: 12/14/2022] Open
Abstract
Cdc48/p97 and the ubiquilin family of UBA-UBL proteins are known for their role in the retrotranslocation of damaged proteins from the endoplasmic reticulum. We demonstrate that Cdc48 and the ubiquilin-like proteins in yeast also play a role in the anterograde trafficking of proteins, in this case the vacuolar protease, Cps1.
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Affiliation(s)
- Rachel Kama
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Galina Gabriely
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Vydehi Kanneganti
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jeffrey E. Gerst
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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13
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Gonzalez AC, Schweizer M, Jagdmann S, Bernreuther C, Reinheckel T, Saftig P, Damme M. Unconventional Trafficking of Mammalian Phospholipase D3 to Lysosomes. Cell Rep 2018; 22:1040-1053. [PMID: 29386126 DOI: 10.1016/j.celrep.2017.12.100] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/10/2017] [Accepted: 12/26/2017] [Indexed: 01/08/2023] Open
Abstract
Variants in the phospholipase D3 (PLD3) gene have genetically been linked to late-onset Alzheimer's disease. We present a detailed biochemical analysis of PLD3 and reveal its endogenous localization in endosomes and lysosomes. PLD3 reaches lysosomes as a type II transmembrane protein via a (for mammalian cells) uncommon intracellular biosynthetic route that depends on the ESCRT (endosomal sorting complex required for transport) machinery. PLD3 is sorted into intraluminal vesicles of multivesicular endosomes, and ESCRT-dependent sorting correlates with ubiquitination. In multivesicular endosomes, PLD3 is subjected to proteolytic cleavage, yielding a stable glycosylated luminal polypeptide and a rapidly degraded N-terminal membrane-bound fragment. This pathway closely resembles the delivery route of carboxypeptidase S to the yeast vacuole. Our experiments reveal a biosynthetic route of PLD3 involving proteolytic processing and ESCRT-dependent sorting for its delivery to lysosomes in mammalian cells.
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Affiliation(s)
| | - Michaela Schweizer
- Center of Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - Sebastian Jagdmann
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel 24118, Germany
| | - Christian Bernreuther
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Reinheckel
- Institute of Molecular Medicine and Cell Research, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Paul Saftig
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel 24118, Germany
| | - Markus Damme
- Biochemical Institute, Christian-Albrechts-University of Kiel, Kiel 24118, Germany.
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14
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Sun A, Wei J, Childress C, Shaw JH, Peng K, Shao G, Yang W, Lin Q. The E3 ubiquitin ligase NEDD4 is an LC3-interactive protein and regulates autophagy. Autophagy 2017; 13:522-537. [PMID: 28085563 DOI: 10.1080/15548627.2016.1268301] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The MAP1LC3/LC3 family plays an essential role in autophagosomal biogenesis and transport. In this report, we show that the HECT family E3 ubiquitin ligase NEDD4 interacts with LC3 and is involved in autophagosomal biogenesis. NEDD4 binds to LC3 through a conserved WXXL LC3-binding motif in a region between the C2 and the WW2 domains. Knockdown of NEDD4 impaired starvation- or rapamycin-induced activation of autophagy and autophagosomal biogenesis and caused aggregates of the LC3 puncta colocalized with endoplasmic reticulum membrane markers. Electron microscopy observed gigantic deformed mitochondria in NEDD4 knockdown cells, suggesting that NEDD4 might function in mitophagy. Furthermore, SQSTM1 is ubiquitinated by NEDD4 while LC3 functions as an activator of NEDD4 ligase activity. Taken together, our studies define an important role of NEDD4 in regulation of autophagy.
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Affiliation(s)
- Aiqin Sun
- a School of Medicine, Jiangsu University , Zhenjiang , China
| | - Jing Wei
- a School of Medicine, Jiangsu University , Zhenjiang , China
| | - Chandra Childress
- b Department of Biology , Susquehanna University , Selinsgrove , PA , USA
| | - John H Shaw
- c Department of Pathology , Geisinger Clinic , Danville , PA , USA
| | - Ke Peng
- a School of Medicine, Jiangsu University , Zhenjiang , China
| | - Genbao Shao
- a School of Medicine, Jiangsu University , Zhenjiang , China
| | - Wannian Yang
- a School of Medicine, Jiangsu University , Zhenjiang , China
| | - Qiong Lin
- a School of Medicine, Jiangsu University , Zhenjiang , China
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15
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Johnson N, West M, Odorizzi G. Regulation of yeast ESCRT-III membrane scission activity by the Doa4 ubiquitin hydrolase. Mol Biol Cell 2017; 28:661-672. [PMID: 28057764 PMCID: PMC5328624 DOI: 10.1091/mbc.e16-11-0761] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/15/2016] [Accepted: 12/30/2016] [Indexed: 11/23/2022] Open
Abstract
Doa4 is the ubiquitin hydrolase in yeast that deubiquitinates transmembrane proteins sorted by ESCRTs. Results support a model for bidirectional regulation between Doa4 and the ESCRT-III complex. ESCRT-III executes membrane scission during the budding of intralumenal vesicles (ILVs) at endosomes. The scission mechanism is unknown but appears to be linked to the cycle of assembly and disassembly of ESCRT-III complexes at membranes. Regulating this cycle is therefore expected to be important for determining the timing of ESCRT-III–mediated membrane scission. We show that in Saccharomyces cerevisiae, ESCRT-III complexes are stabilized and ILV membrane scission is delayed by Doa4, which is the ubiquitin hydrolase that deubiquitinates transmembrane proteins sorted as cargoes into ILVs. These results suggest a mechanism to delay ILV budding while cargoes undergo deubiquitination. We further show that deubiquitination of ILV cargoes is inhibited via Doa4 binding to Vps20, which is the subunit of ESCRT-III that initiates assembly of the complex. Current models suggest that ESCRT-III complexes surround ubiquitinated cargoes to trap them at the site of ILV budding while the cargoes undergo deubiquitination. Thus our results also propose a mechanism to prevent the onset of ILV cargo deubiquitination at the initiation of ESCRT-III complex assembly.
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Affiliation(s)
- Natalie Johnson
- Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Matt West
- Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Greg Odorizzi
- Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309
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16
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Sunshine AB, Ong GT, Nickerson DP, Carr D, Murakami CJ, Wasko BM, Shemorry A, Merz AJ, Kaeberlein M, Dunham MJ. Aneuploidy shortens replicative lifespan in Saccharomyces cerevisiae. Aging Cell 2016; 15:317-24. [PMID: 26762766 PMCID: PMC4783355 DOI: 10.1111/acel.12443] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2015] [Indexed: 11/28/2022] Open
Abstract
Aneuploidy and aging are correlated; however, a causal link between these two phenomena has remained elusive. Here, we show that yeast disomic for a single native yeast chromosome generally have a decreased replicative lifespan. In addition, the extent of this lifespan deficit correlates with the size of the extra chromosome. We identified a mutation in BUL1 that rescues both the lifespan deficit and a protein trafficking defect in yeast disomic for chromosome 5. Bul1 is an E4 ubiquitin ligase adaptor involved in a protein quality control pathway that targets membrane proteins for endocytosis and destruction in the lysosomal vacuole, thereby maintaining protein homeostasis. Concurrent suppression of the aging and trafficking phenotypes suggests that disrupted membrane protein homeostasis in aneuploid yeast may contribute to their accelerated aging. The data reported here demonstrate that aneuploidy can impair protein homeostasis, shorten lifespan, and may contribute to age-associated phenotypes.
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Affiliation(s)
- Anna B. Sunshine
- Department of Genome SciencesUniversity of WashingtonFoege Building, Room S403B, 3720 15th Ave NE, Box 355065SeattleWA98195‐5065USA
| | - Giang T. Ong
- Department of Genome SciencesUniversity of WashingtonFoege Building, Room S403B, 3720 15th Ave NE, Box 355065SeattleWA98195‐5065USA
| | - Daniel P. Nickerson
- Departments of Biochemistry and Physiology and BiophysicsUniversity of WashingtonRoom HSB J‐355, 1705 NE Pacific St, UW box 357350SeattleWA98195‐7350USA
| | - Daniel Carr
- Department of PathologyUniversity of WashingtonRoom HSB D‐514, 1705 NE Pacific St, Box 357470SeattleWA98195‐7470USA
| | - Christopher J. Murakami
- Department of PathologyUniversity of WashingtonRoom HSB D‐514, 1705 NE Pacific St, Box 357470SeattleWA98195‐7470USA
| | - Brian M. Wasko
- Department of PathologyUniversity of WashingtonRoom HSB D‐514, 1705 NE Pacific St, Box 357470SeattleWA98195‐7470USA
| | - Anna Shemorry
- Department of PathologyUniversity of WashingtonRoom HSB D‐514, 1705 NE Pacific St, Box 357470SeattleWA98195‐7470USA
| | - Alexey J. Merz
- Departments of Biochemistry and Physiology and BiophysicsUniversity of WashingtonRoom HSB J‐355, 1705 NE Pacific St, UW box 357350SeattleWA98195‐7350USA
| | - Matt Kaeberlein
- Department of PathologyUniversity of WashingtonRoom HSB D‐514, 1705 NE Pacific St, Box 357470SeattleWA98195‐7470USA
| | - Maitreya J. Dunham
- Department of Genome SciencesUniversity of WashingtonFoege Building, Room S403B, 3720 15th Ave NE, Box 355065SeattleWA98195‐5065USA
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17
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Watanabe D, Murai H, Tanahashi R, Nakamura K, Sasaki T, Takagi H. Cooperative and selective roles of the WW domains of the yeast Nedd4-like ubiquitin ligase Rsp5 in the recognition of the arrestin-like adaptors Bul1 and Bul2. Biochem Biophys Res Commun 2015; 463:76-81. [DOI: 10.1016/j.bbrc.2015.05.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 05/09/2015] [Indexed: 11/28/2022]
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18
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Comparative Analysis of Transmembrane Regulators of the Filamentous Growth Mitogen-Activated Protein Kinase Pathway Uncovers Functional and Regulatory Differences. EUKARYOTIC CELL 2015; 14:868-83. [PMID: 26116211 DOI: 10.1128/ec.00085-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 06/17/2015] [Indexed: 12/14/2022]
Abstract
Filamentous growth is a microbial differentiation response that involves the concerted action of multiple signaling pathways. In budding yeast, one pathway that regulates filamentous growth is a Cdc42p-dependent mitogen-activated protein kinase (MAPK) pathway. Several transmembrane (TM) proteins regulate the filamentous growth pathway, including the signaling mucin Msb2p, the tetraspan osmosensor Sho1p, and an adaptor Opy2p. The TM proteins were compared to identify common and unique features. Msb2p, Sho1p, and Opy2p associated by coimmunoprecipitation analysis but showed predominantly different localization patterns. The different localization patterns of the proteins resulted in part from different rates of turnover from the plasma membrane (PM). In particular, Msb2p (and Opy2p) were turned over rapidly compared to Sho1p. Msb2p signaled from the PM, and its turnover was a rate-limiting step in MAPK signaling. Genetic analysis identified unique phenotypes of cells overexpressing the TM proteins. Therefore, each TM regulator of the filamentous growth pathway has its own regulatory pattern and specific function in regulating filamentous growth. This specialization may be important for fine-tuning and potentially diversifying the filamentation response.
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19
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Role of the unfolded protein response in regulating the mucin-dependent filamentous-growth mitogen-activated protein kinase pathway. Mol Cell Biol 2015; 35:1414-32. [PMID: 25666509 DOI: 10.1128/mcb.01501-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Signaling mucins are evolutionarily conserved regulators of signal transduction pathways. The signaling mucin Msb2p regulates the Cdc42p-dependent mitogen-activated protein kinase (MAPK) pathway that controls filamentous growth in yeast. The cleavage and release of the glycosylated inhibitory domain of Msb2p is required for MAPK activation. We show here that proteolytic processing of Msb2p was induced by underglycosylation of its extracellular domain. Cleavage of underglycosylated Msb2p required the unfolded protein response (UPR), a quality control (QC) pathway that operates in the endoplasmic reticulum (ER). The UPR regulator Ire1p, which detects misfolded/underglycosylated proteins in the ER, controlled Msb2p cleavage by regulating transcriptional induction of Yps1p, the major protease that processes Msb2p. Accordingly, the UPR was required for differentiation to the filamentous cell type. Cleavage of Msb2p occurred in conditional trafficking mutants that trap secretory cargo in the endomembrane system. Processed Msb2p was delivered to the plasma membrane, and its turnover by the ubiquitin ligase Rsp5p and ESCRT attenuated the filamentous-growth pathway. We speculate that the QC pathways broadly regulate signaling glycoproteins and their cognate pathways by recognizing altered glycosylation patterns that can occur in response to extrinsic cues.
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20
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Specific α-arrestins negatively regulate Saccharomyces cerevisiae pheromone response by down-modulating the G-protein-coupled receptor Ste2. Mol Cell Biol 2014; 34:2660-81. [PMID: 24820415 DOI: 10.1128/mcb.00230-14] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are integral membrane proteins that initiate responses to extracellular stimuli by mediating ligand-dependent activation of cognate heterotrimeric G proteins. In yeast, occupancy of GPCR Ste2 by peptide pheromone α-factor initiates signaling by releasing a stimulatory Gβγ complex (Ste4-Ste18) from its inhibitory Gα subunit (Gpa1). Prolonged pathway stimulation is detrimental, and feedback mechanisms have evolved that act at the receptor level to limit the duration of signaling and stimulate recovery from pheromone-induced G1 arrest, including upregulation of the expression of an α-factor-degrading protease (Bar1), a regulator of G-protein signaling protein (Sst2) that stimulates Gpa1-GTP hydrolysis, and Gpa1 itself. Ste2 is also downregulated by endocytosis, both constitutive and ligand induced. Ste2 internalization requires its phosphorylation and subsequent ubiquitinylation by membrane-localized protein kinases (Yck1 and Yck2) and a ubiquitin ligase (Rsp5). Here, we demonstrate that three different members of the α-arrestin family (Ldb19/Art1, Rod1/Art4, and Rog3/Art7) contribute to Ste2 desensitization and internalization, and they do so by discrete mechanisms. We provide genetic and biochemical evidence that Ldb19 and Rod1 recruit Rsp5 to Ste2 via PPXY motifs in their C-terminal regions; in contrast, the arrestin fold domain at the N terminus of Rog3 is sufficient to promote adaptation. Finally, we show that Rod1 function requires calcineurin-dependent dephosphorylation.
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21
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Erpapazoglou Z, Walker O, Haguenauer-Tsapis R. Versatile roles of k63-linked ubiquitin chains in trafficking. Cells 2014; 3:1027-88. [PMID: 25396681 PMCID: PMC4276913 DOI: 10.3390/cells3041027] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/14/2014] [Accepted: 10/21/2014] [Indexed: 12/11/2022] Open
Abstract
Modification by Lys63-linked ubiquitin (UbK63) chains is the second most abundant form of ubiquitylation. In addition to their role in DNA repair or kinase activation, UbK63 chains interfere with multiple steps of intracellular trafficking. UbK63 chains decorate many plasma membrane proteins, providing a signal that is often, but not always, required for their internalization. In yeast, plants, worms and mammals, this same modification appears to be critical for efficient sorting to multivesicular bodies and subsequent lysosomal degradation. UbK63 chains are also one of the modifications involved in various forms of autophagy (mitophagy, xenophagy, or aggrephagy). Here, in the context of trafficking, we report recent structural studies investigating UbK63 chains assembly by various E2/E3 pairs, disassembly by deubiquitylases, and specifically recognition as sorting signals by receptors carrying Ub-binding domains, often acting in tandem. In addition, we address emerging and unanticipated roles of UbK63 chains in various recycling pathways that function by activating nucleators required for actin polymerization, as well as in the transient recruitment of signaling molecules at the plasma or ER membrane. In this review, we describe recent advances that converge to elucidate the mechanisms underlying the wealth of trafficking functions of UbK63 chains.
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Affiliation(s)
- Zoi Erpapazoglou
- Institut Jacques Monod-CNRS, UMR 7592, Université-Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
| | - Olivier Walker
- Institut des Sciences Analytiques, UMR5280, Université de Lyon/Université Lyon 1, 69100 Villeurbanne, France.
| | - Rosine Haguenauer-Tsapis
- Institut Jacques Monod-CNRS, UMR 7592, Université-Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
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22
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Hecht KA, O'Donnell AF, Brodsky JL. The proteolytic landscape of the yeast vacuole. CELLULAR LOGISTICS 2014; 4:e28023. [PMID: 24843828 PMCID: PMC4022603 DOI: 10.4161/cl.28023] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 01/27/2014] [Accepted: 01/28/2014] [Indexed: 01/07/2023]
Abstract
The vacuole in the yeast Saccharomyces cerevisiae plays a number of essential roles, and to provide some of these required functions the vacuole harbors at least seven distinct proteases. These proteases exhibit a range of activities and different classifications, and they follow unique paths to arrive at their ultimate, common destination in the cell. This review will first summarize the major functions of the yeast vacuole and delineate how proteins are targeted to this organelle. We will then describe the specific trafficking itineraries and activities of the characterized vacuolar proteases, and outline select features of a new member of this protease ensemble. Finally, we will entertain the question of why so many proteases evolved and reside in the vacuole, and what future research challenges exist in the field.
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Affiliation(s)
- Karen A Hecht
- Department of Biological Sciences; University of Pittsburgh; Pittsburgh, PA USA
| | - Allyson F O'Donnell
- Department of Cell Biology; University of Pittsburgh School of Medicine; Pittsburgh, PA USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences; University of Pittsburgh; Pittsburgh, PA USA
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23
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Morvan J, de Craene JO, Rinaldi B, Addis V, Misslin C, Friant S. Btn3 regulates the endosomal sorting function of the yeast Ent3 epsin, an adaptor for SNARE proteins. J Cell Sci 2014; 128:706-16. [DOI: 10.1242/jcs.159699] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Ent3 and Ent5 are yeast epsin N-terminal homology (ENTH) domain containing proteins involved in protein trafficking between the Golgi and late endosomes (LE). They interact with clathrin, clathrin adaptor at the Golgi (AP-1 and GGA) and different SNAREs (Vti1, Snc1, Pep12 and Syn8) required for vesicular transport at the Golgi and endosomes. To better understand the role of these epsins in membrane trafficking, we performed a protein-protein interaction screen. We identified Btn3/Tda3, a putative oxidoreductase, as a new partner of both Ent3 and Ent5. Btn3 is a negative regulator of the Batten disease linked protein Btn2 involved in the retrieval of specific SNAREs (Vti1, Snc1, Tlg1 and Tlg2) from the LE to the Golgi. We show that Btn3 endosomal localization depends on epsins Ent3 and Ent5. We demonstrated that in btn3Δ mutant cells, endosomal sorting of ubiquitinated cargos and endosomal recycling of the Snc1 SNARE are delayed. We thus propose that Btn3 regulates the sorting function of two adaptors for SNARE proteins, the epsin Ent3 and the Batten disease linked protein Btn2.
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24
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Kolb AR, Needham PG, Rothenberg C, Guerriero CJ, Welling PA, Brodsky JL. ESCRT regulates surface expression of the Kir2.1 potassium channel. Mol Biol Cell 2013; 25:276-89. [PMID: 24227888 PMCID: PMC3890348 DOI: 10.1091/mbc.e13-07-0394] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Kir2.1 potassium channel is targeted by endoplasmic reticulum–associated degradation in yeast. To identify other Kir2.1 quality control factors, a novel yeast screen was performed. ESCRT components were among the strongest hits from the screen. Consistent with these data, ESCRT also regulates Kir2.1 stability in human cells. Protein quality control (PQC) is required to ensure cellular health. PQC is recognized for targeting the destruction of defective polypeptides, whereas regulated protein degradation mechanisms modulate the concentration of specific proteins in concert with physiological demands. For example, ion channel levels are physiologically regulated within tight limits, but a system-wide approach to define which degradative systems are involved is lacking. We focus on the Kir2.1 potassium channel because altered Kir2.1 levels lead to human disease and Kir2.1 restores growth on low-potassium medium in yeast mutated for endogenous potassium channels. Using this system, first we find that Kir2.1 is targeted for endoplasmic reticulum–associated degradation (ERAD). Next a synthetic gene array identifies nonessential genes that negatively regulate Kir2.1. The most prominent gene family that emerges from this effort encodes members of endosomal sorting complex required for transport (ESCRT). ERAD and ESCRT also mediate Kir2.1 degradation in human cells, with ESCRT playing a more prominent role. Thus multiple proteolytic pathways control Kir2.1 levels at the plasma membrane.
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Affiliation(s)
- Alexander R Kolb
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15261 Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
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25
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Abstract
E3 ligases comprise a highly diverse and important group of enzymes that act within the 26S ubiquitin proteasome pathway. They facilitate the transfer of ubiquitin moieties to substrate proteins which may be marked for degradation by this step. As such, they serve as central regulators in many cellular and physiological processes in plants. The review provides an update on the multitude of different E3 ligases currently known in plants, and illustrates the central role in plant biology of specific examples.
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Affiliation(s)
- Liyuan Chen
- Plant Stress Physiology, School of Biological Sciences, Abelson 435, PO Box 644236, Washington State University, Pullman, WA 99164-4236, USA
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26
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Norgan AP, Lee JRE, Oestreich AJ, Payne JA, Krueger EW, Katzmann DJ. ESCRT-independent budding of HIV-1 gag virus-like particles from Saccharomyces cerevisiae spheroplasts. PLoS One 2012; 7:e52603. [PMID: 23285107 PMCID: PMC3528670 DOI: 10.1371/journal.pone.0052603] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 11/20/2012] [Indexed: 12/28/2022] Open
Abstract
Heterologous expression of HIV-1 Gag in a variety of host cells results in its packaging into virus-like particles (VLPs) that are subsequently released into the extracellular milieu. This phenomenon represents a useful tool for probing cellular factors required for viral budding and has contributed to the discovery of roles for ubiquitin ligases and the endosomal sorting complexes required for transport (ESCRTs) in viral budding. These factors are highly conserved throughout eukaryotes and have been studied extensively in the yeast Saccharomyces cerevisiae, a model eukaryote previously utilized as a host for the production of VLPs. We used heterologous expression of HIV Gag in yeast spheroplasts to examine the role of ESCRTs and associated factors (Rsp5, a HECT ubiquitin ligase of the Nedd4 family; Bro1, a homolog of Alix; and Vps4, the AAA-ATPase required for ESCRT function in all contexts/organisms investigated) in the generation of VLPs. Our data reveal: 1) characterized Gag-ESCRT interaction motifs (late domains) are not required for VLP budding, 2) loss of function alleles of the essential HECT ubiquitin ligase Rsp5 do not display defects in VLP formation, and 3) ESCRT function is not required for VLP formation from spheroplasts. These results suggest that the egress of HIV Gag from yeast cells is distinct from the most commonly described mode of exit from mammalian cells, instead mimicking ESCRT-independent VLP formation observed in a subset of mammalian cells. As such, budding of Gag from yeast cells appears to represent ESCRT-independent budding relevant to viral replication in at least some situations. Thus the myriad of genetic and biochemical tools available in the yeast system may be of utility in the study of this aspect of viral budding.
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Affiliation(s)
- Andrew P. Norgan
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Jacqueline R. E. Lee
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Andrea J. Oestreich
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Johanna A. Payne
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Eugene W. Krueger
- Center for Cell Signaling in Gastroenterology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - David J. Katzmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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27
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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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28
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Oh Y, Franck WL, Han SO, Shows A, Gokce E, Muddiman DC, Dean RA. Polyubiquitin is required for growth, development and pathogenicity in the rice blast fungus Magnaporthe oryzae. PLoS One 2012; 7:e42868. [PMID: 22900059 PMCID: PMC3416782 DOI: 10.1371/journal.pone.0042868] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 07/12/2012] [Indexed: 02/01/2023] Open
Abstract
Protein ubiquitination, which is highly selective, regulates many important biological processes including cellular differentiation and pathogenesis in eukaryotic cells. Here, we integrated pharmacological, molecular and proteomic approaches to explore the role of ubiquitination in Magnaporthe oryzae, the leading fungal disease of rice world-wide. Inhibition of ubiquitin-mediated proteolysis using the 26S proteasome inhibitor, Bortezomib, significantly attenuated conidia germination, appressorium formation and pathogenicity in M. oryzae. Gene expression analysis revealed that many genes associated with protein ubiquitination were developmentally regulated during conidia germination. Only a few, including a polyubiquitin encoding gene, MGG_01282, were more abundantly expressed during appressorium formation and under nitrogen starvation. Targeted gene deletion of MGG_01282, in addition to a significant reduction in protein ubiquitination as determined by immuno blot assays, resulted in pleiotropic effects on M. oryzae including reduced growth and sporulation, abnormal conidia morphology, reduced germination and appressorium formation, and the inability to cause disease. Mutants were also defective in sexual development and were female sterile. Using mass spectrometry, we identified 63 candidate polyubiquitinated proteins under nitrogen starvation, which included overrepresentation of proteins involved in translation, transport and protein modification. Our study suggests that ubiquitination of target proteins plays an important role in nutrient assimilation, development and pathogenicity of M. oryzae.
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Affiliation(s)
- Yeonyee Oh
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - William L. Franck
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Sang-Oh Han
- Department of Medicine, Duke University, Durham, North Carolina, United States of America
| | - Angela Shows
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Emine Gokce
- W. M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina, United States of America
| | - David C. Muddiman
- W. M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Ralph A. Dean
- Center for Integrated Fungal Research, Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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29
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Cai Y, Zhuang X, Wang J, Wang H, Lam SK, Gao C, Wang X, Jiang L. Vacuolar degradation of two integral plasma membrane proteins, AtLRR84A and OsSCAMP1, is cargo ubiquitination-independent and prevacuolar compartment-mediated in plant cells. Traffic 2012; 13:1023-40. [PMID: 22486829 DOI: 10.1111/j.1600-0854.2012.01360.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 04/02/2012] [Accepted: 04/04/2012] [Indexed: 12/31/2022]
Abstract
In plant cells, how integral plasma membrane (PM) proteins are degraded in a cargo ubiquitination-independent manner remains elusive. Here, we studied the degradative pathway of two plant PM proteins: AtLRR84A, a type I integral membrane protein belonging to the leucine-rich repeat receptor-like kinase protein family, and OsSCAMP1 (rice secretory carrier membrane protein 1), a tetraspan transmembrane protein located on the PM and trans-Golgi network (TGN) or early endosome (EE). Using wortmannin and ARA7(Q69L) mutant that could enlarge the multivesicular body (MVB) or prevacuolar compartment (PVC) as tools, we demonstrated that, when expressed as green fluorescent protein (GFP) fusions in tobacco BY-2 or Arabidopsis protoplasts, both AtLRR84A and OsSCAMP1 were degraded in the lytic vacuole via the internal vesicles of MVB/PVC in a cargo ubiquitination-independent manner. Such MVB/PVC-mediated vacuolar degradation of PM proteins was further supported by immunocytochemical electron microscopy (immunoEM) study showing the labeling of the fusions on the internal vesicles of the PVC/MVB. Thus, cargo ubiquitination-independent and PVC-mediated degradation of PM proteins in the vacuole is functionally operated in plant cells.
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Affiliation(s)
- Yi Cai
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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30
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Jarmoszewicz K, Łukasiak K, Riezman H, Kaminska J. Rsp5 ubiquitin ligase is required for protein trafficking in Saccharomyces cerevisiae COPI mutants. PLoS One 2012; 7:e39582. [PMID: 22761830 PMCID: PMC3383674 DOI: 10.1371/journal.pone.0039582] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 05/24/2012] [Indexed: 11/24/2022] Open
Abstract
Retrograde trafficking from the Golgi to the endoplasmic reticulum (ER) depends on the formation of vesicles coated with the multiprotein complex COPI. In Saccharomyces cerevisiae ubiquitinated derivatives of several COPI subunits have been identified. The importance of this modification of COPI proteins is unknown. With the exception of the Sec27 protein (β'COP) neither the ubiquitin ligase responsible for ubiquitination of COPI subunits nor the importance of this modification are known. Here we find that the ubiquitin ligase mutation, rsp5-1, has a negative effect that is additive with ret1-1 and sec28Δ mutations, in genes encoding α- and ε-COP, respectively. The double ret1-1 rsp5-1 mutant is also more severely defective in the Golgi-to-ER trafficking compared to the single ret1-1, secreting more of the ER chaperone Kar2p, localizing Rer1p mostly to the vacuole, and increasing sensitivity to neomycin. Overexpression of ubiquitin in ret1-1 rsp5-1 mutant suppresses vacuolar accumulation of Rer1p. We found that the effect of rsp5 mutation on the Golgi-to-ER trafficking is similar to that of sla1Δ mutation in a gene encoding actin cytoskeleton proteins, an Rsp5p substrate. Additionally, Rsp5 and Sla1 proteins were found by co-immunoprecipitation in a complex containing COPI subunits. Together, our results show that Rsp5 ligase plays a role in regulating retrograde Golgi-to-ER trafficking.
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Affiliation(s)
- Katarzyna Jarmoszewicz
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Łukasiak
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Howard Riezman
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Joanna Kaminska
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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31
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Hassink G, Slotman J, Oorschot V, Van Der Reijden BA, Monteferrario D, Noordermeer SM, Van Kerkhof P, Klumperman J, Strous GJ. Identification of the ubiquitin ligase Triad1 as a regulator of endosomal transport. Biol Open 2012; 1:607-14. [PMID: 23213454 PMCID: PMC3509441 DOI: 10.1242/bio.2012778] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The ubiquitin system plays an important role in trafficking of signaling receptors from the plasma membrane to lysosomes. Triad1 is a ubiquitin ligase that catalyzes the formation of poly-ubiquitin chains linked via lysine-48 as well as lysine-63 residues. We show that depletion of Triad1 affects the sorting of both growth hormone and epidermal growth factor. Triad1-depleted cells accumulate both ligands in endosomes. While fluid phase transport to the lysosomes is reduced in the absence of Triad1, growth hormone receptor can recycle back to the plasma membrane together with transferrin. Using immune electron microscopy we show that Triad1 depletion results in enlarged endosomes with enlarged and irregular shaped intraluminal vesicles. The endosomes display prominent clathrin coats and show increased levels of growth hormone label. We conclude that Triad1 is required for the proper function of multivesicular bodies.
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Affiliation(s)
- Gerco Hassink
- Department of Cell Biology and Institute of Biomembranes, University Medical Center Utrecht , 3584 CX Utrecht , The Netherlands
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32
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Erpapazoglou Z, Dhaoui M, Pantazopoulou M, Giordano F, Mari M, Léon S, Raposo G, Reggiori F, Haguenauer-Tsapis R. A dual role for K63-linked ubiquitin chains in multivesicular body biogenesis and cargo sorting. Mol Biol Cell 2012; 23:2170-83. [PMID: 22493318 PMCID: PMC3364180 DOI: 10.1091/mbc.e11-10-0891] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In yeast, the sorting of transmembrane proteins into the multivesicular body (MVB) internal vesicles requires their ubiquitylation by the ubiquitin ligase Rsp5. This allows their recognition by the ubiquitin-binding domains (UBDs) of several endosomal sorting complex required for transport (ESCRT) subunits. K63-linked ubiquitin (K63Ub) chains decorate several MVB cargoes, and accordingly we show that they localize prominently to the class E compartment, which accumulates ubiquitylated cargoes in cells lacking ESCRT components. Conversely, yeast cells unable to generate K63Ub chains displayed MVB sorting defects. These properties are conserved among eukaryotes, as the mammalian melanosomal MVB cargo MART-1 is modified by K63Ub chains and partly missorted when the genesis of these chains is inhibited. We show that all yeast UBD-containing ESCRT proteins undergo ubiquitylation and deubiquitylation, some being modified through the opposing activities of Rsp5 and the ubiquitin isopeptidase Ubp2, which are known to assemble and disassemble preferentially K63Ub chains, respectively. A failure to generate K63Ub chains in yeast leads to an MVB ultrastructure alteration. Our work thus unravels a double function of K63Ub chains in cargo sorting and MVB biogenesis.
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Affiliation(s)
- Zoi Erpapazoglou
- Institut Jacques Monod, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7592, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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33
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Abstract
From the moment of cotranslational insertion into the lipid bilayer of the endoplasmic reticulum (ER), newly synthesized integral membrane proteins are subject to a complex series of sorting, trafficking, quality control, and quality maintenance systems. Many of these processes are intimately controlled by ubiquitination, a posttranslational modification that directs trafficking decisions related to both the biosynthetic delivery of proteins to the plasma membrane (PM) via the secretory pathway and the removal of proteins from the PM via the endocytic pathway. Ubiquitin modification of integral membrane proteins (or "cargoes") generally acts as a sorting signal, which is recognized, captured, and delivered to a specific cellular destination via specialized trafficking events. By affecting the quality, quantity, and localization of integral membrane proteins in the cell, defects in these processes contribute to human diseases, including cystic fibrosis, circulatory diseases, and various neuropathies. This review summarizes our current understanding of how ubiquitin modification influences cargo trafficking, with a special emphasis on mechanisms of quality control and quality maintenance in the secretory and endocytic pathways.
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Affiliation(s)
- Jason A MacGurn
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA.
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34
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MacDonald C, Stringer DK, Piper RC. Sna3 is an Rsp5 adaptor protein that relies on ubiquitination for its MVB sorting. Traffic 2012; 13:586-98. [PMID: 22212814 DOI: 10.1111/j.1600-0854.2011.01326.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 12/27/2011] [Accepted: 12/29/2011] [Indexed: 01/24/2023]
Abstract
The process in which ubiquitin (Ub) conjugation is required for trafficking of integral membrane proteins into multivesicular bodies (MVBs) and eventual degradation in the lumen of lysosomes/vacuoles is well defined. However, Ub-independent pathways into MVBs are less understood. To better understand this process, we have further characterized the membrane protein Sna3, the prototypical Ub-independent cargo protein sorted through the MVB pathway in yeast. We show that Sna3 trafficking to the vacuole is critically dependent on Rsp5 ligase activity and ubiquitination. We find Sna3 undergoes Ub-dependent MVB sorting by either becoming ubiquitinated itself or associating with other ubiquitinated membrane protein substrates. In addition, our functional studies support a role for Sna3 as an adaptor protein that recruits Rsp5 to cargo such as the methionine transporter Mup1, resulting in efficient Mup1 delivery to the vacuole.
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Affiliation(s)
- Chris MacDonald
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52246, USA
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35
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Liu BA, Shah E, Jablonowski K, Stergachis A, Engelmann B, Nash PD. The SH2 domain-containing proteins in 21 species establish the provenance and scope of phosphotyrosine signaling in eukaryotes. Sci Signal 2011; 4:ra83. [PMID: 22155787 DOI: 10.1126/scisignal.2002105] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The Src homology 2 (SH2) domains are participants in metazoan signal transduction, acting as primary mediators for regulated protein-protein interactions with tyrosine-phosphorylated substrates. Here, we describe the origin and evolution of SH2 domain proteins by means of sequence analysis from 21 eukaryotic organisms from the basal unicellular eukaryotes, where SH2 domains first appeared, through the multicellular animals and increasingly complex metazoans. On the basis of our results, SH2 domains and phosphotyrosine signaling emerged in the early Unikonta, and the numbers of SH2 domains expanded in the choanoflagellate and metazoan lineages with the development of tyrosine kinases, leading to rapid elaboration of phosphotyrosine signaling in early multicellular animals. Our results also indicated that SH2 domains coevolved and the number of the domains expanded alongside protein tyrosine kinases and tyrosine phosphatases, thereby coupling phosphotyrosine signaling to downstream signaling networks. Gene duplication combined with domain gain or loss produced novel SH2-containing proteins that function within phosphotyrosine signaling, which likely have contributed to diversity and complexity in metazoans. We found that intra- and intermolecular interactions within and between SH2 domain proteins increased in prevalence along with organismal complexity and may function to generate more highly connected and robust phosphotyrosine signaling networks.
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Affiliation(s)
- Bernard A Liu
- Ben May Department for Cancer Research, University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
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36
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Kaminska J, Spiess M, Stawiecka-Mirota M, Monkaityte R, Haguenauer-Tsapis R, Urban-Grimal D, Winsor B, Zoladek T. Yeast Rsp5 ubiquitin ligase affects the actin cytoskeleton in vivo and in vitro. Eur J Cell Biol 2011; 90:1016-28. [DOI: 10.1016/j.ejcb.2011.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 08/11/2011] [Accepted: 08/17/2011] [Indexed: 10/16/2022] Open
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37
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Synthetic biology approach to reconstituting the ubiquitylation cascade in bacteria. EMBO J 2011; 31:378-90. [PMID: 22081111 DOI: 10.1038/emboj.2011.397] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 10/07/2011] [Indexed: 12/16/2022] Open
Abstract
Covalent modification of proteins with ubiquitin (Ub) is widely implicated in the control of protein function and fate. Over 100 deubiquitylating enzymes rapidly reverse this modification, posing challenges to the biochemical and biophysical characterization of ubiquitylated proteins. We circumvented this limitation with a synthetic biology approach of reconstructing the entire eukaryotic Ub cascade in bacteria. Co-expression of affinity-tagged substrates and Ub with E1, E2 and E3 enzymes allows efficient purification of ubiquitylated proteins in milligram quantity. Contrary to in-vitro assays that lead to spurious modification of several lysine residues of Rpn10 (regulatory proteasomal non-ATPase subunit), the reconstituted system faithfully recapitulates its monoubiquitylation on lysine 84 that is observed in vivo. Mass spectrometry revealed the ubiquitylation sites on the Mind bomb E3 ligase and the Ub receptors Rpn10 and Vps9. Förster resonance energy transfer (FRET) analyses of ubiquitylated Vps9 purified from bacteria revealed that although ubiquitylation occurs on the Vps9-GEF domain, it does not affect the guanine nucleotide exchanging factor (GEF) activity in vitro. Finally, we demonstrated that ubiquitylated Vps9 assumes a closed structure, which blocks additional Ub binding. Characterization of several ubiquitylated proteins demonstrated the integrity, specificity and fidelity of the system, and revealed new biological findings.
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38
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Abstract
Multivesicular bodies (MVBs) deliver cargo destined for degradation to the vacuole or lysosome. The ESCRT (endosomal sorting complex required for transport) pathway is a key mediator of MVB biogenesis, but it also plays critical roles in retroviral budding and cytokinetic abscission. Despite these diverse roles, the ESCRT pathway can be simply seen as a cargo-recognition and membrane-sculpting machine viewable from three distinct perspectives: (1) the ESCRT proteins themselves, (2) the cargo they sort, and (3) the membrane they deform. Here, we review ESCRT function from these perspectives and discuss how ESCRTs may drive vesicle budding.
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39
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Cholbinski P, Jastrzebska Z, Wysocka-Kapcinska M, Plochocka D, Gornicka A, Hopper AK, Zoladek T. Yeast ubiquitin ligase Rsp5 contains nuclear localization and export signals. Eur J Cell Biol 2011; 90:834-43. [PMID: 21868125 PMCID: PMC3167943 DOI: 10.1016/j.ejcb.2011.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 06/07/2011] [Accepted: 06/15/2011] [Indexed: 01/25/2023] Open
Abstract
The Rsp5 ubiquitin ligase regulates numerous cellular processes. Rsp5 is mainly localized to the cytoplasm but nuclear localization was also reported. A potential nuclear export signal was tested for activity by using a GFP(2) reporter. The 687-LIGGIAEIDI-696 sequence located in the Hect domain was identified as a nuclear export signal active in a Crm1-dependent manner, and its importance for the localization of Rsp5 was documented by using fluorescence microscopy and a lacZ-based reporter system. Analysis of the cellular location of other Rsp5 fragments fused with GFP(2) indicated two independent potential nuclear localization signals, both located in the Hect domain. We also uncovered Rsp5 fragments that are important to targeting/tethering Rsp5 to various regions in the cytoplasm. The presented data indicate that Rsp5 ligase is a shuttling protein whose distribution within the cytoplasm and partitioning between cytoplasmic and nuclear locations is determined by a balance between the actions of several targeting sequences and domains.
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Affiliation(s)
- Piotr Cholbinski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Zaneta Jastrzebska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | | | - Danuta Plochocka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Gornicka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | | | - Teresa Zoladek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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40
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Abstract
Over the past 14 years, ubiquitination has emerged as a centrally important mechanism governing the subcellular trafficking of proteins. Ubiquitination, interaction with sorting factors that contain ubiquitin-binding domains, and deubiquitination govern the itineraries of cargo proteins that include yeast carboxypeptidase S, the epithelial sodium channel ENaC, and epidermal growth factor receptor. The molecular structures and mechanisms of the paradigmatic HECT and RING domain ubiquitin ligases, of JAMM- and USP-domain-deubiquitinating enzymes, and of numerous ubiquitin-binding domains involved in these pathways have been worked out in recent years and are described.
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Affiliation(s)
- James H Hurley
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0580, USA.
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41
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Wang S, Thibault G, Ng DTW. Routing misfolded proteins through the multivesicular body (MVB) pathway protects against proteotoxicity. J Biol Chem 2011; 286:29376-29387. [PMID: 21708947 DOI: 10.1074/jbc.m111.233346] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The secretory pathway maintains multiple quality control checkpoints. Initially, endoplasmic reticulum-associated degradation pathways monitor protein folding to retain and eliminate aberrant products. Despite its broad client range, some molecules escape detection and traffic to Golgi membranes. There, a poorly understood mechanism termed Golgi quality control routes aberrant proteins for lysosomal/vacuolar degradation. To better understand Golgi quality control, we examined the processing of the obligate substrate Wsc1p. Misfolded Wsc1p does not use routes of typical vacuolar membrane proteins. Instead, it partitions into intralumenal vesicles of the multivesicular body (MVB) pathway, mediated by the E3 ubiquitin ligase Rsp5p. Its subsequent transport to the vacuolar lumen is essential for complete molecule breakdown. Surprisingly, the transport mode plays a second crucial function in neutralizing potential substrate toxicity. Eliminating the MVB sorting signal diverted molecules to the vacuolar limiting membrane, resulting in the generation of toxic by-products. These data demonstrate a new role of the MVB pathway in protein quality control.
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Affiliation(s)
- Songyu Wang
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore
| | - Guillaume Thibault
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore
| | - Davis T W Ng
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
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42
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Stewart EV, Nwosu CC, Tong Z, Roguev A, Cummins TD, Kim DU, Hayles J, Park HO, Hoe KL, Powell DW, Krogan NJ, Espenshade PJ. Yeast SREBP cleavage activation requires the Golgi Dsc E3 ligase complex. Mol Cell 2011; 42:160-71. [PMID: 21504829 DOI: 10.1016/j.molcel.2011.02.035] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 12/29/2010] [Accepted: 02/22/2011] [Indexed: 12/25/2022]
Abstract
Mammalian lipid homeostasis requires proteolytic activation of membrane-bound sterol regulatory element binding protein (SREBP) transcription factors through sequential action of the Golgi Site-1 and Site-2 proteases. Here we report that while SREBP function is conserved in fungi, fission yeast employs a different mechanism for SREBP cleavage. Using genetics and biochemistry, we identified four genes defective for SREBP cleavage, dsc1-4, encoding components of a transmembrane Golgi E3 ligase complex with structural homology to the Hrd1 E3 ligase complex involved in endoplasmic reticulum-associated degradation. The Dsc complex binds SREBP and cleavage requires components of the ubiquitin-proteasome pathway: the E2-conjugating enzyme Ubc4, the Dsc1 RING E3 ligase, and the proteasome. dsc mutants display conserved aggravating genetic interactions with components of the multivesicular body pathway in fission yeast and budding yeast, which lacks SREBP. Together, these data suggest that the Golgi Dsc E3 ligase complex functions in a post-ER pathway for protein degradation.
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Affiliation(s)
- Emerson V Stewart
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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43
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Ohzono C, Etoh S, Matsumoto M, Nakayama KI, Hirota Y, Tanaka Y, Fujita H. Nedd4-interacting protein 2, a short half-life membrane protein degraded in lysosomes, negatively controls down-regulation of connexin43. Biol Pharm Bull 2011; 33:951-7. [PMID: 20522958 DOI: 10.1248/bpb.33.951] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nedd4-interacting protein 2 (NDFIP2) has three transmembrane domains and interacts with multiple Nedd4 family ubiquitin ligases through polyprolinetyrosine (PY) motifs located in its N-terminal cytoplasmic domain. It has been postulated that NDFIP2 acts as an adaptor for the ubiquitylation of substrates with Nedd4 ubiquitin ligase. However, whether NDFIP2 promotes or inhibits the ubiquitylation of Nedd4 substrates is still under debate. We show here that although NDFIP2 is detected in the Golgi/trans-Golgi network (TGN) area, it is rapidly delivered to and degraded in lysosomes with its half-life ca. 1.5 h. Intriguingly, knockdown (KD) of NDFIP2 with small interfering RNA (siRNA) impaired both the formation and function of gap junctions. Indeed, KD of NDFIP2 destabilized the gap junction protein connexin43 that contains PY motif. In support of this, overexpression of NDFIP2 stabilized connexin43 and enhanced the formation of gap junctions. Furthermore, the PY motifs of NDFIP2, which are required for its interaction with Nedd4, Atrophin-1 interacting protein (AIP) 4 (AIP4)/Itch, and AIP2/WWP2, were necessary for the targeting of NDFIP2 to lysosomes and/or the stability of connexin43 and gap junctions. Collectively these findings suggest that NDFIP2 may inhibit the Nedd4-dependent ubiquitylation of membrane proteins containing PY motifs, such as connexin43, in a competitive manner.
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Affiliation(s)
- Chiho Ohzono
- Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Abstract
The ESCRT (endosomal sorting complex required for transport) machinery is a group of multisubunit protein complexes conserved across phyla that are involved in a range of diverse cellular processes. ESCRT proteins regulate the biogenesis of MVBs (multivesicular bodies) and the sorting of ubiquitinated cargos on to ILVs (intraluminal vesicles) within these MVBs. These proteins are also recruited to sites of retroviral particle assembly, where they provide an activity that allows release of these retroviruses. More recently, these proteins have been shown to be recruited to the intracellular bridge linking daughter cells at the end of mitosis, where they act to ensure the separation of these cells through the process of cytokinesis. Although these cellular processes are diverse, they share a requirement for a topologically unique membrane-fission step for their completion. Current models suggest that the ESCRT machinery catalyses this membrane fission.
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Nickerson DP, West M, Henry R, Odorizzi G. Regulators of Vps4 ATPase activity at endosomes differentially influence the size and rate of formation of intralumenal vesicles. Mol Biol Cell 2010; 21:1023-32. [PMID: 20089837 PMCID: PMC2836955 DOI: 10.1091/mbc.e09-09-0776] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Disassembly of ESCRT-III requires Vps4 ATPase activity under the control of regulatory proteins. Described here are distinct spatiotemporal functions for Vps4 regulators, with Did2 playing a unique role in regulating MVB lumenal vesicle size and Vtal-Vps60 promoting efficient membrane scission and delivery of vesicles into the endosome lumen. Recruitment of endosomal sorting complexes required for transport (ESCRTs) to the cytosolic face of endosomes regulates selective inclusion of transmembrane proteins into the lumenal vesicles of multivesicular bodies (MVBs). ESCRT-0, -I, and -II bind directly to ubiquitinated transmembrane cargoes of the MVB pathway, whereas polymerization of ESCRT-III at endosomes is thought to bend the membrane and/or provide the energetic force that drives membrane scission and detachment of vesicles into the endosome lumen. Disassembly of the ESCRT-III polymer and dissociation of its subunits from endosomes requires the Vps4 ATPase, the activity of which is controlled in vivo by regulatory proteins. We identify distinct spatiotemporal roles for Vps4-regulating proteins through examinations of subcellular localization and endosome morphology. Did2 plays a unique role in the regulation of MVB lumenal vesicle size, whereas Vtal and Vps60 promote efficient membrane scission and delivery of membrane to the endosome lumen. These morphological effects probably result from Vps4-mediated manipulations of ESCRT-III, because we show dissociation of ESCRT-0, -I, and -II from endosomes is not directly dependent on Vps4 activity.
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Affiliation(s)
- Daniel P Nickerson
- Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
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Late domain-independent rescue of a release-deficient Moloney murine leukemia virus by the ubiquitin ligase itch. J Virol 2009; 84:704-15. [PMID: 19864377 DOI: 10.1128/jvi.01319-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Moloney murine leukemia virus (MoMLV) Gag utilizes its late (L) domain motif PPPY to bind members of the Nedd4-like ubiquitin ligase family. These interactions recruit components of the cell's budding machinery that are critical for virus release. MoMLV Gag contains two additional L domains, PSAP and LYPAL, that are believed to drive residual MoMLV release via interactions with cellular proteins Tsg101 and Alix, respectively. We found that overexpression of Tsg101 or Alix failed to rescue the release of PPPY-deficient MoMLV via these other L domains. However, low-level expression of the ubiquitin ligase Itch potently rescued the release and infectivity of MoMLV lacking PPPY function. In contrast, other ubiquitin ligases such as WWP1, Nedd4.1, Nedd4.2, and Nedd4.2s did not rescue this release-deficient virus. Efficient rescue required the ubiquitin ligase activity of Itch and an intact C2 domain but not presence of the endophilin-binding site. Additionally, we found Itch to immunoprecipitate with MoMLV Gag lacking the PPPY motif and to be incorporated into rescued MoMLV particles. The PSAP and LYPAL motifs were dispensable for Itch-mediated virus rescue, and their absence did not affect the incorporation of Itch into the rescued particles. Itch-mediated rescue of release-defective MoMLV was sensitive to inhibition by dominant-negative versions of ESCRT-III components and the VPS4 AAA ATPase, indicating that Itch-mediated correction of MoMLV release defects requires the integrity of the host vacuolar sorting protein pathway. RNA interference knockdown of Itch suppressed the residual release of the MoMLV lacking the PPPY motif. Interestingly, Itch stimulation of the PPPY-deficient MoMLV release was accompanied by the enhancement of Gag ubiquitination and the appearance of new ubiquitinated Gag proteins in virions. Together, these results suggest that Itch can facilitate MoMLV release in an L domain-independent manner via a mechanism that requires the host budding machinery and involves Gag ubiquitination.
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Everaerts W, Nilius B, Owsianik G. The vanilloid transient receptor potential channel TRPV4: from structure to disease. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2009; 103:2-17. [PMID: 19835908 DOI: 10.1016/j.pbiomolbio.2009.10.002] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Accepted: 10/07/2009] [Indexed: 12/19/2022]
Abstract
The Transient Receptor Potential Vanilloid 4 channel, TRPV4, is a Ca(2+) and Mg(2+) permeable non-selective cation channel involved in many different cellular functions. It is activated by a variety of physical and chemical stimuli, including heat, mechano-stimuli, endogenous substances such as arachidonic acid and its cytochrome P450-derived metabolites (epoxyeicosatrienoic acids), endocannabinoids (anandamide and 2-arachidonoylglycerol), as well as synthetic alpha-phorbol derivatives. Recently, TRPV4 has been characterized as an important player modulating osteoclast differentiation in bone remodelling and as a urothelial mechanosensor that controls normal voiding. Several TRPV4 gain-of-function mutations are shown to cause autosomal-dominant bone dysplasias such as brachyolmia and Koszlowski disease. In this review we comprehensively describe the structural, biophysical and (patho)physiological properties of the TRPV4 channel and we summarize the current knowledge about the role of TRPV4 in the pathogenesis of several diseases.
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Affiliation(s)
- Wouter Everaerts
- Department of Molecular Cell Biology, Laboratory Ion Channel Research, Campus Gasthuisberg, KULeuven, Herestraat 49, bus 802, B-3000 Leuven, Belgium
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Lee JRE, Oestreich AJ, Payne JA, Gunawan MS, Norgan AP, Katzmann DJ. The HECT domain of the ubiquitin ligase Rsp5 contributes to substrate recognition. J Biol Chem 2009; 284:32126-37. [PMID: 19744925 DOI: 10.1074/jbc.m109.048629] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Ubiquitin modification of endosomal membrane proteins is a signal for active inclusion into the Multivesicular Body (MVB) pathway, resulting in lysosomal degradation. However, the endosome represents a dynamic site of protein sorting with a majority of proteins destined for recycling, rather than MVB targeting. Substrate recognition by ubiquitin ligases is therefore highly regulated. We have investigated substrate recognition by the Nedd4 ortholog Rsp5 as a model for understanding ligase-substrate interactions. Rsp5 interacts directly with its substrate Cps1 via a novel interaction mode. Perturbation of this mode of interaction revealed a compensatory role for the Rsp5 adaptor Bsd2. These results highlight the ability of Rsp5 to interact with substrates via multiple modalities, suggesting additional mechanisms of regulating this interaction and relevant outcomes.
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Affiliation(s)
- Jacqueline R E Lee
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Paiva S, Vieira N, Nondier I, Haguenauer-Tsapis R, Casal M, Urban-Grimal D. Glucose-induced ubiquitylation and endocytosis of the yeast Jen1 transporter: role of lysine 63-linked ubiquitin chains. J Biol Chem 2009; 284:19228-36. [PMID: 19433580 DOI: 10.1074/jbc.m109.008318] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein ubiquitylation is essential for many events linked to intracellular protein trafficking. Despite the significance of this process, the molecular mechanisms that govern the regulation of ubiquitylation remain largely unknown. Plasma membrane transporters are subjected to tightly regulated endocytosis, and ubiquitylation is a key signal at several stages of the endocytic pathway. The yeast monocarboxylate transporter Jen1 displays glucose-regulated endocytosis. We show here that casein kinase 1-dependent phosphorylation and HECT-ubiquitin ligase Rsp5-dependent ubiquitylation are required for Jen1 endocytosis. Ubiquitylation and endocytosis of Jen1 are induced within minutes in response to glucose addition. Jen1 is modified at the cell surface by oligo-ubiquitylation with ubiquitin-Lys(63) linked chain(s), and Jen1-Lys(338) is one of the target residues. Ubiquitin-Lys(63)-linked chain(s) are also required directly or indirectly to sort Jen1 into multivesicular bodies. Jen1 is one of the few examples for which ubiquitin-Lys(63)-linked chain(s) was shown to be required for correct trafficking at two stages of endocytosis: endocytic internalization and sorting at multivesicular bodies.
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Affiliation(s)
- Sandra Paiva
- Department of Biology, Molecular and Environmental Biology Centre, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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50
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Lauwers E, Jacob C, André B. K63-linked ubiquitin chains as a specific signal for protein sorting into the multivesicular body pathway. ACTA ACUST UNITED AC 2009; 185:493-502. [PMID: 19398763 PMCID: PMC2700384 DOI: 10.1083/jcb.200810114] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
A growing number of yeast and mammalian plasma membrane proteins are reported to be modified with K63-linked ubiquitin (Ub) chains. However, the relative importance of this modification versus monoubiquitylation in endocytosis, Golgi to endosome traffic, and sorting into the multivesicular body (MVB) pathway remains unclear. In this study, we show that K63-linked ubiquitylation of the Gap1 permease is essential for its entry into the MVB pathway. Carboxypeptidase S also requires modification with a K63-Ub chain for correct MVB sorting. In contrast, monoubiquitylation of a single target lysine of Gap1 is a sufficient signal for its internalization from the cell surface, and Golgi to endosome transport of the permease requires neither its ubiquitylation nor the Ub-binding GAT (Gga and Tom1) domain of Gga (Golgi localizing, gamma-ear containing, ARF binding) adapter proteins, the latter being crucial for subsequent MVB sorting of the permease. Our data reveal that K63-linked Ub chains act as a specific signal for MVB sorting, providing further insight into the Ub code of membrane protein trafficking.
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Affiliation(s)
- Elsa Lauwers
- Laboratoire de Physiologie Moléculaire de la Cellule, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, Gosselies, Belgium
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