1
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Martins TS, Correia M, Pinheiro D, Lemos C, Mendes MV, Pereira C, Costa V. Sit4 Genetically Interacts with Vps27 to Regulate Mitochondrial Function and Lifespan in Saccharomyces cerevisiae. Cells 2024; 13:655. [PMID: 38667270 PMCID: PMC11049076 DOI: 10.3390/cells13080655] [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: 01/06/2024] [Revised: 03/27/2024] [Accepted: 04/06/2024] [Indexed: 04/28/2024] Open
Abstract
The Sit4 protein phosphatase plays a key role in orchestrating various cellular processes essential for maintaining cell viability during aging. We have previously shown that SIT4 deletion promotes vacuolar acidification, mitochondrial derepression, and oxidative stress resistance, increasing yeast chronological lifespan. In this study, we performed a proteomic analysis of isolated vacuoles and yeast genetic interaction analysis to unravel how Sit4 influences vacuolar and mitochondrial function. By employing high-resolution mass spectrometry, we show that sit4Δ vacuolar membranes were enriched in Vps27 and Hse1, two proteins that are part of the endosomal sorting complex required for transport-0. In addition, SIT4 exhibited a negative genetic interaction with VPS27, as sit4∆vps27∆ double mutants had a shortened lifespan compared to sit4∆ and vps27∆ single mutants. Our results also show that Vps27 did not increase sit4∆ lifespan by improving protein trafficking or vacuolar sorting pathways. However, Vps27 was critical for iron homeostasis and mitochondrial function in sit4∆ cells, as sit4∆vps27∆ double mutants exhibited high iron levels and impaired mitochondrial respiration. These findings show, for the first time, cross-talk between Sit4 and Vps27, providing new insights into the mechanisms governing chronological lifespan.
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Affiliation(s)
- Telma S. Martins
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (T.S.M.); (M.C.); (D.P.); (C.L.); (M.V.M.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
- ICBAS—Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Miguel Correia
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (T.S.M.); (M.C.); (D.P.); (C.L.); (M.V.M.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Denise Pinheiro
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (T.S.M.); (M.C.); (D.P.); (C.L.); (M.V.M.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Carolina Lemos
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (T.S.M.); (M.C.); (D.P.); (C.L.); (M.V.M.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
- ICBAS—Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Marta Vaz Mendes
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (T.S.M.); (M.C.); (D.P.); (C.L.); (M.V.M.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Clara Pereira
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (T.S.M.); (M.C.); (D.P.); (C.L.); (M.V.M.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Vítor Costa
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (T.S.M.); (M.C.); (D.P.); (C.L.); (M.V.M.)
- IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
- ICBAS—Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
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2
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Diep DTV, Collado J, Hugenroth M, Fausten RM, Percifull L, Wälte M, Schuberth C, Schmidt O, Fernández-Busnadiego R, Bohnert M. A metabolically controlled contact site between vacuoles and lipid droplets in yeast. Dev Cell 2024; 59:740-758.e10. [PMID: 38367622 DOI: 10.1016/j.devcel.2024.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 11/17/2023] [Accepted: 01/18/2024] [Indexed: 02/19/2024]
Abstract
The lipid droplet (LD) organization proteins Ldo16 and Ldo45 affect multiple aspects of LD biology in yeast. They are linked to the LD biogenesis machinery seipin, and their loss causes defects in LD positioning, protein targeting, and breakdown. However, their molecular roles remained enigmatic. Here, we report that Ldo16/45 form a tether complex with Vac8 to create vacuole lipid droplet (vCLIP) contact sites, which can form in the absence of seipin. The phosphatidylinositol transfer protein (PITP) Pdr16 is a further vCLIP-resident recruited specifically by Ldo45. While only an LD subpopulation is engaged in vCLIPs at glucose-replete conditions, nutrient deprivation results in vCLIP expansion, and vCLIP defects impair lipophagy upon prolonged starvation. In summary, Ldo16/45 are multifunctional proteins that control the formation of a metabolically regulated contact site. Our studies suggest a link between LD biogenesis and breakdown and contribute to a deeper understanding of how lipid homeostasis is maintained during metabolic challenges.
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Affiliation(s)
- Duy Trong Vien Diep
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Javier Collado
- Institute of Neuropathology, University Medical Center Göttingen, 37099 Göttingen, Germany
| | - Marie Hugenroth
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Rebecca Martina Fausten
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Louis Percifull
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Mike Wälte
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany
| | - Christian Schuberth
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Oliver Schmidt
- Institute of Cell Biology, Biocenter Innsbruck, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Rubén Fernández-Busnadiego
- Institute of Neuropathology, University Medical Center Göttingen, 37099 Göttingen, Germany; Cluster of Excellence "Multiscale Imaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany; Faculty of Physics, University of Göttingen, Göttingen 37077, Germany
| | - Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany.
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3
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Nenciarini S, Cavalieri D. Immunomodulatory Potential of Fungal Extracellular Vesicles: Insights for Therapeutic Applications. Biomolecules 2023; 13:1487. [PMID: 37892168 PMCID: PMC10605264 DOI: 10.3390/biom13101487] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/30/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
Extracellular vesicles (EVs) are membranous vesicular organelles that perform a variety of biological functions including cell communication across different biological kingdoms. EVs of mammals and, to a lesser extent, bacteria have been deeply studied over the years, whereas investigations of fungal EVs are still in their infancy. Fungi, encompassing both yeast and filamentous forms, are increasingly recognized for their production of extracellular vesicles (EVs) containing a wealth of proteins, lipids, and nucleic acids. These EVs play pivotal roles in orchestrating fungal communities, bolstering pathogenicity, and mediating interactions with the environment. Fungal EVs have emerged as promising candidates for innovative applications, not only in the management of mycoses but also as carriers for therapeutic molecules. Yet, numerous questions persist regarding fungal EVs, including their mechanisms of generation, release, cargo regulation, and discharge. This comprehensive review delves into the present state of knowledge regarding fungal EVs and provides fresh insights into the most recent hypotheses on the mechanisms driving their immunomodulatory properties. Furthermore, we explore the considerable potential of fungal EVs in the realms of medicine and biotechnology. In the foreseeable future, engineered fungal cells may serve as vehicles for tailoring cargo- and antigen-specific EVs, positioning them as invaluable biotechnological tools for diverse medical applications, such as vaccines and drug delivery.
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Affiliation(s)
| | - Duccio Cavalieri
- Department of Biology, University of Florence, Via Madonna del Piano 6, Sesto Fiorentino, 50019 Florence, Italy;
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4
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Golden CK, Kazmirchuk TDD, McNally EK, El eissawi M, Gokbayrak ZD, Richard JD, Brett CL. A two-tiered system for selective receptor and transporter protein degradation. PLoS Genet 2022; 18:e1010446. [PMID: 36215320 PMCID: PMC9584418 DOI: 10.1371/journal.pgen.1010446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 10/20/2022] [Accepted: 09/26/2022] [Indexed: 11/06/2022] Open
Abstract
Diverse physiology relies on receptor and transporter protein down–regulation and degradation mediated by ESCRTs. Loss–of–function mutations in human ESCRT genes linked to cancers and neurological disorders are thought to block this process. However, when homologous mutations are introduced into model organisms, cells thrive and degradation persists, suggesting other mechanisms compensate. To better understand this secondary process, we studied degradation of transporter (Mup1) or receptor (Ste3) proteins when ESCRT genes (VPS27, VPS36) are deleted in Saccharomyces cerevisiae using live-cell imaging and organelle biochemistry. We find that endocytosis remains intact, but internalized proteins aberrantly accumulate on vacuolar lysosome membranes within cells. Here they are sorted for degradation by the intralumenal fragment (ILF) pathway, constitutively or when triggered by substrates, misfolding or TOR activation in vivo and in vitro. Thus, the ILF pathway functions as fail–safe layer of defense when ESCRTs disregard their clients, representing a two–tiered system that ensures degradation of surface polytopic proteins. Receptor, transporter and channel proteins on the plasma membranes (or surface) of all cells mediate extensive physiology. This requires precise control of their numbers, and damaged copies must be removed to prevent cytotoxicity. Their downregulation and degradation is mediated by lysosomes after endocytosis and entry into the multi–vesicular body (MVB) pathway which depends on ESCRTs (Endosomal Sorting Complexes Required for Transport). Loss–of–function mutations in ESCRT genes are linked to cancers and neurological disease, but cells survive and some proteins continue to be degraded. Herein, we use baker’s yeast (Saccharomyces cerevisiae) as model to better understand how surface proteins are degraded in cells missing ESCRT genes. Using fluorescence microscopy matched with biochemical and genetic approaches, we find that the methionine transporter Mup1 and G-protein coupled receptor Ste3 continue to be degraded when two ESCRT genes are deleted. They are endocytosed but rerouted to membranes of vacuolar lysosomes after stimuli are applied to trigger their downregulation. Here they are sorted into intralumenal fragments and degraded by acid hydrolases within vacuolar lysosomes upon homotypic membrane fusion. We propose that this intralumenal fragment (ILF) pathway functions as a secondary mechanism to degrade surface proteins with the canonical MVB pathway is disrupted.
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Affiliation(s)
| | | | - Erin Kate McNally
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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5
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Hatano T, Palani S, Papatziamou D, Salzer R, Souza DP, Tamarit D, Makwana M, Potter A, Haig A, Xu W, Townsend D, Rochester D, Bellini D, Hussain HMA, Ettema TJG, Löwe J, Baum B, Robinson NP, Balasubramanian M. Asgard archaea shed light on the evolutionary origins of the eukaryotic ubiquitin-ESCRT machinery. Nat Commun 2022; 13:3398. [PMID: 35697693 PMCID: PMC9192718 DOI: 10.1038/s41467-022-30656-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 05/10/2022] [Indexed: 11/23/2022] Open
Abstract
The ESCRT machinery, comprising of multiple proteins and subcomplexes, is crucial for membrane remodelling in eukaryotic cells, in processes that include ubiquitin-mediated multivesicular body formation, membrane repair, cytokinetic abscission, and virus exit from host cells. This ESCRT system appears to have simpler, ancient origins, since many archaeal species possess homologues of ESCRT-III and Vps4, the components that execute the final membrane scission reaction, where they have been shown to play roles in cytokinesis, extracellular vesicle formation and viral egress. Remarkably, metagenome assemblies of Asgard archaea, the closest known living relatives of eukaryotes, were recently shown to encode homologues of the entire cascade involved in ubiquitin-mediated membrane remodelling, including ubiquitin itself, components of the ESCRT-I and ESCRT-II subcomplexes, and ESCRT-III and Vps4. Here, we explore the phylogeny, structure, and biochemistry of Asgard homologues of the ESCRT machinery and the associated ubiquitylation system. We provide evidence for the ESCRT-I and ESCRT-II subcomplexes being involved in ubiquitin-directed recruitment of ESCRT-III, as it is in eukaryotes. Taken together, our analyses suggest a pre-eukaryotic origin for the ubiquitin-coupled ESCRT system and a likely path of ESCRT evolution via a series of gene duplication and diversification events.
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Grants
- MC_U105184326 Medical Research Council
- MC_UP_1201/27 Medical Research Council
- 203276/Z/16/Z Wellcome Trust
- Wellcome Trust
- WT101885MA Wellcome Trust
- Wellcome Trust (Wellcome)
- Leverhulme Trust
- Svenska Forskningsrådet Formas (Swedish Research Council Formas)
- Above funding attributed to the authors as follows (from paper acknowledgements): Computational analysis was facilitated by resources provided by the Swedish National Infrastructure for Computing (SNIC) at the Uppsala Multidisciplinary Center for Advanced Computational Science (UPPMAX), partially funded by the Swedish Research Council through grant agreement no. 2018-05973. We thank the Warwick Proteomics RTP for mass spectrometry. MKB was supported by the Wellcome Trust (WT101885MA) and the European Research Council (ERC-2014-ADG No. 671083). Work by the NR laboratory was supported by start-up funds from the Division of Biomedical and Life Sciences (BLS, Lancaster University) and a Leverhulme Research Project Grant (RPG-2019-297). NR would like to thank Johanna Syrjanen for performing trial expressions of the Odinarchaeota ESCRT proteins, and Joseph Maman for helpful discussion regarding the SEC-MALS. NR, WX and AP would like to thank Charley Lai and Siu-Kei Yau for assistance with initial Odinarchaeota ESCRT protein purifications. DPS and BB would like to thank Chris Johnson at the MRC LMB Biophysics facility for performing the SEC-MALS assay on Heimdallarchaeotal Vps22. TH, HH, MB, RS, JL, D Tamarit, TE, DPS and BB received support from a Wellcome Trust collaborative award (203276/Z/16/Z). BB and DPS were supported by the MRC. D Tamarit was supported by the Swedish Research Council (International Postdoc grant 2018-06609).
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Affiliation(s)
- Tomoyuki Hatano
- Centre for Mechanochemical Cell Biology, Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK
| | - Saravanan Palani
- Centre for Mechanochemical Cell Biology, Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Dimitra Papatziamou
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YG, UK
| | - Ralf Salzer
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Diorge P Souza
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Daniel Tamarit
- Laboratory of Microbiology, Wageningen University, 6708 WE, Wageningen, The Netherlands
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, SE-75007, Uppsala, Sweden
| | - Mehul Makwana
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YG, UK
| | - Antonia Potter
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YG, UK
| | - Alexandra Haig
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YG, UK
| | - Wenjue Xu
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YG, UK
| | - David Townsend
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
| | - David Rochester
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
| | - Dom Bellini
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Hamdi M A Hussain
- Centre for Mechanochemical Cell Biology, Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK
| | - Thijs J G Ettema
- Laboratory of Microbiology, Wageningen University, 6708 WE, Wageningen, The Netherlands
| | - Jan Löwe
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Buzz Baum
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
| | - Nicholas P Robinson
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YG, UK.
| | - Mohan Balasubramanian
- Centre for Mechanochemical Cell Biology, Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK.
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6
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Eising S, Esch B, Wälte M, Vargas Duarte P, Walter S, Ungermann C, Bohnert M, Fröhlich F. A lysosomal biogenesis map reveals the cargo spectrum of yeast vacuolar protein targeting pathways. J Cell Biol 2022; 221:213011. [PMID: 35175277 PMCID: PMC8859911 DOI: 10.1083/jcb.202107148] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/20/2021] [Accepted: 01/18/2022] [Indexed: 12/15/2022] Open
Abstract
The lysosome is the major catabolic organelle in the cell that has been established as a key metabolic signaling center. Mutations in many lysosomal proteins have catastrophic effects and cause neurodegeneration, cancer, and age-related diseases. The vacuole is the lysosomal analog of Saccharomyces cerevisiae that harbors many evolutionary conserved proteins. Proteins reach vacuoles via the Vps10-dependent endosomal vacuolar protein sorting pathway, via the alkaline phosphatase (ALP or AP-3) pathway, and via the cytosol-to-vacuole transport (CVT) pathway. A systematic understanding of the cargo spectrum of each pathway is completely lacking. Here, we use quantitative proteomics of purified vacuoles to generate the yeast lysosomal biogenesis map. This dataset harbors information on the cargo-receptor relationship of almost all vacuolar proteins. We map binding motifs of Vps10 and the AP-3 complex and identify a novel cargo of the CVT pathway under nutrient-rich conditions. Our data show how organelle purification and quantitative proteomics can uncover fundamental insights into organelle biogenesis.
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Affiliation(s)
- Sebastian Eising
- Molecular Membrane Biology Group, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Bianca Esch
- Molecular Membrane Biology Group, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Mike Wälte
- Institute of Cell Dynamics and Imaging, University of Münster, Münster, Germany
| | - Prado Vargas Duarte
- Biochemistry Section, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Biochemistry Section, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück, Osnabrück University, Osnabrück, Germany
| | - Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster, Münster, Germany.,Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | - Florian Fröhlich
- Molecular Membrane Biology Group, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany.,Biochemistry Section, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
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7
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Lemus L, Matić Z, Gal L, Fadel A, Schuldiner M, Goder V. Post-ER degradation of misfolded GPI-anchored proteins is linked with microautophagy. Curr Biol 2021; 31:4025-4037.e5. [PMID: 34314677 DOI: 10.1016/j.cub.2021.06.078] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/07/2021] [Accepted: 06/25/2021] [Indexed: 01/08/2023]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are membrane-conjugated cell-surface proteins with diverse structural, developmental, and signaling functions and clinical relevance. Typically, after biosynthesis and attachment to the preassembled GPI anchor, GPI-APs rapidly leave the endoplasmic reticulum (ER) and rely on post-ER quality control. Terminally misfolded GPI-APs end up inside the vacuole/lysosome for degradation, but their trafficking itinerary to this organelle and the processes linked to their uptake by the vacuole/lysosome remain uncharacterized. In a yeast mutant that is lacking Pep4, a key vacuolar protease, several misfolded model GPI-APs accumulated in the vacuolar membrane. In the same mutant, macroautophagy and the multi-vesicular body (MVB) pathway were intact, hinting at a hitherto-unknown trafficking pathway for the degradation of misfolded GPI-APs. To unravel it, we used a genome-wide screen coupled to high-throughput fluorescence microscopy and followed the fate of the misfolded GPI-AP: Gas1∗. We found that components of the early secretory and endocytic pathways are involved in its targeting to the vacuole and that vacuolar transporter chaperones (VTCs), with roles in microautophagy, negatively affect the vacuolar uptake of Gas1∗. In support, we demonstrate that Gas1∗ internalizes from vacuolar membranes into membrane-bound intravacuolar vesicles prior to degradation. Our data link post-ER degradation with microautophagy.
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Affiliation(s)
- Leticia Lemus
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
| | - Zrinka Matić
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain
| | - Lihi Gal
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Amir Fadel
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Veit Goder
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
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8
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Zhang A, Meng Y, Li Q, Liang Y. The endosomal sorting complex required for transport complex negatively regulates Erg6 degradation under specific glucose restriction conditions. Traffic 2021; 21:488-502. [PMID: 32378292 DOI: 10.1111/tra.12732] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 12/20/2022]
Abstract
Lipid droplets (LDs) are cytosolic fat storage organelles that play roles in lipid metabolism, trafficking and signaling. Breakdown of LDs in Saccharomyces cerevisiae is mainly achieved by lipolysis and lipophagy. In this study, we found that the endosomal sorting complex required for transport (ESCRT) in S. cerevisiae negatively regulated the turnover of a LD marker, Erg6, under both simplified glucose restriction (GR) and acute glucose restriction (AGR) conditions by monitoring the localization and degradation of Erg6. Loss of Vps27, Snf7 or Vps4, representative subunits of the ESCRT machinery, facilitated the delivery of Erg6-GFP to vacuoles and its degradation depending on the lipophagy protein Atg15 under simplified GR. Additionally, the lipolysis proteins Tgl3 and Tgl4 were also involved in the enhanced vacuolar localization and degradation of Erg6-GFP in vps4Δ cells. Furthermore, we found that Atg14, which is required for the formation of putatively liquid-ordered (Lo) membrane domains on the vacuole that act as preferential internalization sites for LDs, abundantly localized to vacuolar membranes in ESCRT mutants. Most importantly, the depletion or overexpression of Atg14 correspondingly abolished or promoted the observed Erg6 degradation in ESCRT mutant cells. We propose that Atg14 together with other proteins promotes Erg6 degradation in ESCRT mutant cells under specific glucose restriction conditions. These results shed new light on the regulation of ESCRT on LD turnover.
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Affiliation(s)
- Ao Zhang
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Ying Meng
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Qunli Li
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Yongheng Liang
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
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9
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Avalos-Padilla Y, Georgiev VN, Lantero E, Pujals S, Verhoef R, N. Borgheti-Cardoso L, Albertazzi L, Dimova R, Fernàndez-Busquets X. The ESCRT-III machinery participates in the production of extracellular vesicles and protein export during Plasmodium falciparum infection. PLoS Pathog 2021; 17:e1009455. [PMID: 33798247 PMCID: PMC9159051 DOI: 10.1371/journal.ppat.1009455] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 04/14/2021] [Accepted: 03/08/2021] [Indexed: 01/08/2023] Open
Abstract
Infection with Plasmodium falciparum enhances extracellular
vesicle (EV) production in parasitized red blood cells (pRBCs), an important
mechanism for parasite-to-parasite communication during the asexual
intraerythrocytic life cycle. The endosomal
sorting complex
required for transport
(ESCRT), and in particular the ESCRT-III sub-complex, participates in the
formation of EVs in higher eukaryotes. However, RBCs have lost the majority of
their organelles through the maturation process, including an important
reduction in their vesicular network. Therefore, the mechanism of EV production
in P. falciparum-infected RBCs remains to be
elucidated. Here we demonstrate that P.
falciparum possesses a functional ESCRT-III machinery
activated by an alternative recruitment pathway involving the action of PfBro1
and PfVps32/PfVps60 proteins. Additionally, multivesicular body formation and
membrane shedding, both reported mechanisms of EV production, were reconstituted
in the membrane model of giant unilamellar vesicles using the purified
recombinant proteins. Moreover, the presence of PfVps32, PfVps60 and PfBro1 in
EVs purified from a pRBC culture was confirmed by super-resolution microscopy
and dot blot assays. Finally, disruption of the PfVps60 gene
led to a reduction in the number of the produced EVs in the KO strain and
affected the distribution of other ESCRT-III components. Overall, our results
increase the knowledge on the underlying molecular mechanisms during malaria
pathogenesis and demonstrate that ESCRT-III P.
falciparum proteins participate in EV production. Malaria is a disease caused by Plasmodium parasites that is
still a leading cause of death in many low-income countries, and for which
currently available therapeutic strategies are not succeeding in its control,
let alone eradication. An interesting feature observed after
Plasmodium invasion is the increase of extracellular
vesicles (EVs) generated by parasitized red blood cells (pRBCs), which lack a
vesicular trafficking that would explain EV production. Here, by combining
different approaches, we demonstrated the participation of the
endosomal sorting
complex required for
transport (ESCRT) machinery from Plasmodium
falciparum in the production of EVs in pRBCs. Moreover, we were
able to detect ESCRT-III proteins adjacent to the membrane of the host and in
EVs purified from a pRBC culture, which shows the export of these proteins and
their participation in EV production. Finally, the disruption of an ESCRT-III
associated gene, Pfvps60, led to a significant reduction in the
amount of EVs. Altogether, these results confirm ESCRT-III participation in EV
production and provide novel information on the P.
falciparum protein export mechanisms, which can be used for
the development of new therapeutic strategies against malaria, based on the
disruption of EV formation and trafficking.
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Affiliation(s)
- Yunuen Avalos-Padilla
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute
of Science and Technology (BIST), Barcelona, Spain
- Barcelona Institute for Global Health (ISGlobal, Hospital
Clínic-Universitat de Barcelona), Barcelona, Spain
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids
and Interfaces, Science Park Golm, Potsdam, Germany
- * E-mail: (YA-P); (XF-B)
| | - Vasil N. Georgiev
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids
and Interfaces, Science Park Golm, Potsdam, Germany
| | - Elena Lantero
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute
of Science and Technology (BIST), Barcelona, Spain
- Barcelona Institute for Global Health (ISGlobal, Hospital
Clínic-Universitat de Barcelona), Barcelona, Spain
| | - Silvia Pujals
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute
of Science and Technology (BIST), Barcelona, Spain
- Department of Electronics and Biomedical Engineering, Faculty of Physics,
Universitat de Barcelona, Barcelona, Spain
| | - René Verhoef
- Computational Biology Group, Eindhoven University of Technology,
Eindhoven, The Netherlands
| | - Livia N. Borgheti-Cardoso
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute
of Science and Technology (BIST), Barcelona, Spain
| | - Lorenzo Albertazzi
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute
of Science and Technology (BIST), Barcelona, Spain
- Department of Biomedical Engineering and the Institute for Complex
Molecular Systems, Eindhoven University of Technology, Eindhoven, The
Netherlands
| | - Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids
and Interfaces, Science Park Golm, Potsdam, Germany
| | - Xavier Fernàndez-Busquets
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute
of Science and Technology (BIST), Barcelona, Spain
- Barcelona Institute for Global Health (ISGlobal, Hospital
Clínic-Universitat de Barcelona), Barcelona, Spain
- * E-mail: (YA-P); (XF-B)
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10
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Biogenesis of Fungal Extracellular Vesicles: What Do We Know? Curr Top Microbiol Immunol 2021; 432:1-11. [DOI: 10.1007/978-3-030-83391-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Pannen H, Rapp T, Klein T. The ESCRT machinery regulates retromer-dependent transcytosis of septate junction components in Drosophila. eLife 2020; 9:61866. [PMID: 33377869 PMCID: PMC7848756 DOI: 10.7554/elife.61866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/29/2020] [Indexed: 12/30/2022] Open
Abstract
Loss of ESCRT function in Drosophila imaginal discs is known to cause neoplastic overgrowth fueled by mis-regulation of signaling pathways. Its impact on junctional integrity, however, remains obscure. To dissect the events leading to neoplasia, we used transmission electron microscopy (TEM) on wing imaginal discs temporally depleted of the ESCRT-III core component Shrub. We find a specific requirement for Shrub in maintaining septate junction (SJ) integrity by transporting the claudin Megatrachea (Mega) to the SJ. In absence of Shrub function, Mega is lost from the SJ and becomes trapped on endosomes coated with the endosomal retrieval machinery retromer. We show that ESCRT function is required for apical localization and mobility of retromer positive carrier vesicles, which mediate the biosynthetic delivery of Mega to the SJ. Accordingly, loss of retromer function impairs the anterograde transport of several SJ core components, revealing a novel physiological role for this ancient endosomal agent. Proteins are large molecules responsible for a variety of activities that cells needs to perform to survive; from respiration to copying DNA before cells divide. To perform these roles proteins need to be transported to the correct cell compartment, or to the cell membrane. This protein trafficking depends on the endosomal system, a set of membrane compartments that can travel within the cell and act as a protein sorting hub. This system needs its own proteins to work properly. In particular, there are two sets of proteins that are crucial for the endosomal systems activity: a group of proteins known as the ESCRT (endosomal sorting complex required for transport) machinery and a complex called retromer. The retromer complex regulates recycling of receptor proteins so they can be reused, while the ESCRT machinery mediates degradation of proteins that the cell does not require anymore. In the epithelia of fruit fly larvae – the tissues that form layers of cells, usually covering an organ but also making structures like wings – defects in ESCRT activity lead to a loss of tissue integrity. This loss of tissue integrity suggests that the endosomal system might be involved in transporting proteins that form cellular junctions, the multiprotein complexes that establish contacts between cells or between a cell and the extracellular space. In arthropods such as the fruit fly, the adherens junction and the septate junction are two types of cellular junctions important for the integrity of epithelia integrity. Adherens junctions allow cells to adhere to each other, while septate junctions stop nutrient molecules, ions and water from leaking into the tissue. The role of the endosomal system in trafficking the proteins that form septate junctions remains a mystery. To better understand the role of the endosomal system in regulating cell junctions and tissue integrity, Pannen et al. blocked the activity of either the ESCRT or retromer in wing imaginal discs – the future wings – of fruit fly larvae. Pannen et al. then analyzed the effects of these endosomal defects on cellular junctions using an imaging technique called transmission electron microscopy. The results showed that both ESCRT and retromer activities are necessary for the correct delivery of septate junction components to the cell membrane. However, neither retromer nor ESCRT were required for the delivery of adherens junction proteins. These findings shed light on how retromer and the ESCRT machinery are involved in the epithelial tissue integrity of fruit fly larvae through their effects on cell junctions. Humans have their own versions of the ESCRT, retromer, and cell junction proteins, all of which are very similar to their fly counterparts. Since defects in the human versions of these proteins have been associated with a variety of diseases, from infections to cancer, these results may have implications for research into treating those diseases.
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Affiliation(s)
- Hendrik Pannen
- Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Tim Rapp
- Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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12
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Chemical-Genetic Interactions with the Proline Analog L-Azetidine-2-Carboxylic Acid in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2020; 10:4335-4345. [PMID: 33082270 PMCID: PMC7718759 DOI: 10.1534/g3.120.401876] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Non-proteinogenic amino acids, such as the proline analog L-azetidine-2-carboxylic acid (AZC), are detrimental to cells because they are mis-incorporated into proteins and lead to proteotoxic stress. Our goal was to identify genes that show chemical-genetic interactions with AZC in Saccharomyces cerevisiae and thus also potentially define the pathways cells use to cope with amino acid mis-incorporation. Screening the yeast deletion and temperature sensitive collections, we found 72 alleles with negative chemical-genetic interactions with AZC treatment and 12 alleles that suppress AZC toxicity. Many of the genes with negative chemical-genetic interactions are involved in protein quality control pathways through the proteasome. Genes involved in actin cytoskeleton organization and endocytosis also had negative chemical-genetic interactions with AZC. Related to this, the number of actin patches per cell increases upon AZC treatment. Many of the same cellular processes were identified to have interactions with proteotoxic stress caused by two other amino acid analogs, canavanine and thialysine, or a mistranslating tRNA variant that mis-incorporates serine at proline codons. Alleles that suppressed AZC-induced toxicity functioned through the amino acid sensing TOR pathway or controlled amino acid permeases required for AZC uptake. Further suggesting the potential of genetic changes to influence the cellular response to proteotoxic stress, overexpressing many of the genes that had a negative chemical-genetic interaction with AZC suppressed AZC toxicity.
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13
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Nguyen V, Smothers J, Ballhorn P, Kottapalli S, Ly A, Villarreal J, Kim K. Myosin V-mediated transport of Snc1 and Vps10 toward the trans-Golgi network. Eur J Cell Biol 2020; 100:151143. [PMID: 33277053 DOI: 10.1016/j.ejcb.2020.151143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 10/30/2020] [Accepted: 11/27/2020] [Indexed: 12/23/2022] Open
Abstract
Retrieval of cargo proteins from the endosome towards the trans-Golgi network (TGN) is a crucial intracellular process for cellular homeostasis. Its dysfunction is associated with pathogenesis of Alzheimer and Parkinson's diseases. Myosin family proteins are cellular motors walking along actin filaments by utilizing the chemical energy from ATP hydrolysis, known to involve in pleiotropic cellular trafficking pathways. However, the question of whether myosins play a role in the trafficking of Snc1 and Vps10 has not been addressed yet. The present study assesses the potential roles of all five yeast myosins in the recycling of two membrane cargo, Snc1 and Vps10. It appears that all myosins except Myo2 are not required for the Snc1 traffic, while it was found that Myo1 and 2 play important roles for Vps10 retrieval from the endosome and the vacuole. Multiple myo2 mutants harboring a point mutation in the actin binding or the cargo binding tail domain were characterized to demonstrate abnormal Vps10-GFP and GFP-Snc1 distribution phenotypes, suggesting a severe defect in their sorting and trafficking at the endosome. Furthermore, Vps10-GFP patches in all tested myo2 mutants were found to be near stationary with quantitative live cell imaging. Finally, we found that actin cables in the myo2 mutant cells were considerably disrupted, which may aggravate the trafficking of Vps10 from the endosome. Together, our results provide novel insights into the function of Myo-family proteins in the recycling traffic of Vps10 and Snc1 destined for the TGN.
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Affiliation(s)
- Vy Nguyen
- Department of Biology, Missouri State University, 901 S National, Springfield, MO, 65807, USA
| | - Jared Smothers
- Department of Biology, Missouri State University, 901 S National, Springfield, MO, 65807, USA; Department of Biophysics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75235-8816, USA
| | - Paul Ballhorn
- Department of Biology, Missouri State University, 901 S National, Springfield, MO, 65807, USA
| | - Sravya Kottapalli
- Department of Biology, Missouri State University, 901 S National, Springfield, MO, 65807, USA
| | - Anh Ly
- Department of Biology, Missouri State University, 901 S National, Springfield, MO, 65807, USA
| | - Julia Villarreal
- Department of Biology, Missouri State University, 901 S National, Springfield, MO, 65807, USA
| | - Kyoungtae Kim
- Department of Biology, Missouri State University, 901 S National, Springfield, MO, 65807, USA.
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14
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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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15
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Xie Q, Chen A, Zhang Y, Zhang C, Hu Y, Luo Z, Wang B, Yun Y, Zhou J, Li G, Wang Z. ESCRT-III accessory proteins regulate fungal development and plant infection in Fusarium graminearum. Curr Genet 2019; 65:1041-1055. [PMID: 30927052 DOI: 10.1007/s00294-019-00949-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/22/2019] [Accepted: 02/28/2019] [Indexed: 12/27/2022]
Abstract
Ubiquitinated biosynthetic and surface proteins destined for degradation are sorted into the lysosome/vacuole via the multivesicular body sorting pathway, which depends on the function of ESCRT machinery. Fusarium head blight (FHB) caused by Fusarium graminearum is one of the most devastating diseases for wheat and barley worldwide. To better understand the role of ESCRT machinery in F. graminearum, we investigated the function of ESCRT-III accessory proteins FgVps60, FgDid2 and FgIst1 in this study. FgVps60-GFP, FgDid2-GFP and FgIst1-GFP are localized to punctate structures adjacent to the vacuolar membrane except for FgIst1-GFP that is also found in the nucleus. Then, the gene deletion mutants ΔFgvps60, ΔFgdid2 and ΔFgist1 displayed defective growth to a different extent. ΔFgvps60 and ΔFgdid2 but not ΔFgist1 also showed significant reduction in hydrophobicity on cell surface, conidiation, perithecia production and virulence. Interestingly, ΔFgist1 mutant produced a significantly higher level of DON while showing a minor reduction in pathogenicity. Microscopic analyses revealed that FgVps60 but not FgIst1 and FgDid2 is necessary for endocytosis. Moreover, spontaneous mutations were identified in the ΔFgvps60 mutant that partially rescued its defects in growth and conidiation. Taken together, we conclude that ESCRT-III accessory proteins play critical roles in growth, reproduction and plant infection in F. graminearum.
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Affiliation(s)
- Qiurong Xie
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China.,Key Laboratory for Plant-Microbe Interaction, School of Life Sciences, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Ahai Chen
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Yunzhi Zhang
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Chengkang Zhang
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Yanpei Hu
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Zenghong Luo
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Baohua Wang
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Yingzi Yun
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China. .,Key Laboratory for Plant-Microbe Interaction, School of Life Sciences, Fujian Agriculture and Forestry University, 350002, Fuzhou, China.
| | - Jie Zhou
- Key Laboratory for Plant-Microbe Interaction, School of Life Sciences, Fujian Agriculture and Forestry University, 350002, Fuzhou, China.
| | - Guangpu Li
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 73104, Oklahoma City, OK, USA. .,Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, 73104, Oklahoma City, OK, USA.
| | - Zonghua Wang
- Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Plant Protection, Fujian Agriculture and Forestry University, 350002, Fuzhou, China. .,Key Laboratory for Plant-Microbe Interaction, School of Life Sciences, Fujian Agriculture and Forestry University, 350002, Fuzhou, China. .,Institute of Oceanography, Minjiang University, 350108, Fuzhou, China.
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16
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Dores MR, Trejo J. Endo-lysosomal sorting of G-protein-coupled receptors by ubiquitin: Diverse pathways for G-protein-coupled receptor destruction and beyond. Traffic 2018; 20:101-109. [PMID: 30353650 DOI: 10.1111/tra.12619] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 10/14/2018] [Accepted: 10/15/2018] [Indexed: 02/06/2023]
Abstract
Ubiquitin is covalently attached to substrate proteins in the form of a single ubiquitin moiety or polyubiquitin chains and has been generally linked to protein degradation, however, distinct types of ubiquitin linkages are also used to control other critical cellular processes like cell signaling. Over forty mammalian G protein-coupled receptors (GPCRs) have been reported to be ubiquitinated, but despite the diverse and rich complexity of GPCR signaling, ubiquitin has been largely ascribed to receptor degradation. Indeed, GPCR ubiquitination targets the receptors for degradation by lysosome, which is mediated by the Endosomal Sorting Complexes Required for Transport (ESCRT) machinery, and the proteasome. This has led to the view that ubiquitin and ESCRTs primarily function as the signal to target GPCRs for destruction. Contrary to this conventional view, studies indicate that ubiquitination of certain GPCRs and canonical ubiquitin-binding ESCRTs are not required for receptor degradation and revealed that diverse and complex pathways exist to regulate endo-lysosomal sorting of GPCRs. In other studies, GPCR ubiquitination has been shown to drive signaling and not receptor degradation and further revealed novel insight into the mechanisms by which GPCRs trigger the activity of the ubiquitination machinery. Here, we discuss the diverse pathways by which ubiquitin controls GPCR endo-lysosomal sorting and beyond.
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Affiliation(s)
- Michael R Dores
- Department of Biology, Hofstra University, Hempstead, New York
| | - JoAnn Trejo
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California
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17
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Gireud-Goss M, Reyes S, Wilson M, Farley M, Memarzadeh K, Srinivasan S, Sirisaengtaksin N, Yamashita S, Tsunoda S, Lang FF, Waxham MN, Bean AJ. Distinct mechanisms enable inward or outward budding from late endosomes/multivesicular bodies. Exp Cell Res 2018; 372:1-15. [PMID: 30144444 DOI: 10.1016/j.yexcr.2018.08.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 12/25/2022]
Abstract
Regulating the residence time of membrane proteins on the cell surface can modify their response to extracellular cues and allow for cellular adaptation in response to changing environmental conditions. The fate of membrane proteins that are internalized from the plasma membrane and arrive at the limiting membrane of the late endosome/multivesicular body (MVB) is dictated by whether they remain on the limiting membrane, bud into internal MVB vesicles, or bud outwardly from the membrane. The molecular details underlying the disposition of membrane proteins that transit this pathway and the mechanisms regulating these trafficking events are unclear. We established a cell-free system that reconstitutes budding of membrane protein cargo into internal MVB vesicles and onto vesicles that bud outwardly from the MVB membrane. Both budding reactions are cytosol-dependent and supported by Saccharomyces cerevisiae (yeast) cytosol. We observed that inward and outward budding from the MVB membrane are mechanistically distinct but may be linked, such that inhibition of inward budding triggers a re-routing of cargo from inward to outward budding vesicles, without affecting the number of vesicles that bud outwardly from MVBs.
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Affiliation(s)
- Monica Gireud-Goss
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
| | - Sahily Reyes
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
| | - Marenda Wilson
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
| | - Madeline Farley
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
| | - Kimiya Memarzadeh
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
| | | | - Natalie Sirisaengtaksin
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
| | - Shinji Yamashita
- Department of Neurosurgery, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
| | - Susan Tsunoda
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
| | - Frederick F Lang
- Department of Neurosurgery, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
| | - M Neal Waxham
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
| | - Andrew J Bean
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Biochemistry and Cell Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA; Department of Pediatrics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
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18
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Naslavsky N, Caplan S. The enigmatic endosome - sorting the ins and outs of endocytic trafficking. J Cell Sci 2018; 131:131/13/jcs216499. [PMID: 29980602 DOI: 10.1242/jcs.216499] [Citation(s) in RCA: 195] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The early endosome (EE), also known as the sorting endosome (SE) is a crucial station for the sorting of cargoes, such as receptors and lipids, through the endocytic pathways. The term endosome relates to the receptacle-like nature of this organelle, to which endocytosed cargoes are funneled upon internalization from the plasma membrane. Having been delivered by the fusion of internalized vesicles with the EE or SE, cargo molecules are then sorted to a variety of endocytic pathways, including the endo-lysosomal pathway for degradation, direct or rapid recycling to the plasma membrane, and to a slower recycling pathway that involves a specialized form of endosome known as a recycling endosome (RE), often localized to the perinuclear endocytic recycling compartment (ERC). It is striking that 'the endosome', which plays such essential cellular roles, has managed to avoid a precise description, and its characteristics remain ambiguous and heterogeneous. Moreover, despite the rapid advances in scientific methodologies, including breakthroughs in light microscopy, overall, the endosome remains poorly defined. This Review will attempt to collate key characteristics of the different types of endosomes and provide a platform for discussion of this unique and fascinating collection of organelles. Moreover, under-developed, poorly understood and important open questions will be discussed.
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Affiliation(s)
- Naava Naslavsky
- The Department of Biochemistry and Molecular Biology, The University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Steve Caplan
- The Department of Biochemistry and Molecular Biology, The University of Nebraska Medical Center, Omaha, NE 68198, USA .,The Fred and Pamela Buffett Cancer Center, The University of Nebraska Medical Center, Omaha, NE 68198, USA
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19
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Day KJ, Casler JC, Glick BS. Budding Yeast Has a Minimal Endomembrane System. Dev Cell 2018; 44:56-72.e4. [PMID: 29316441 DOI: 10.1016/j.devcel.2017.12.014] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 12/01/2017] [Accepted: 12/12/2017] [Indexed: 12/13/2022]
Abstract
The endomembrane system consists of the secretory and endocytic pathways, which communicate by transport to and from the trans-Golgi network (TGN). In mammalian cells, the endocytic pathway includes early, late, and recycling endosomes. In budding yeast, different types of endosomes have been described, but the organization of the endocytic pathway has remained unclear. We performed a spatial and temporal analysis of yeast endosomal markers and endocytic cargoes. Our results indicate that the yeast TGN also serves as an early and recycling endosome. In addition, as previously described, yeast contains a late or prevacuolar endosome (PVE). Endocytic cargoes localize to the TGN shortly after internalization, and manipulations that perturb export from the TGN can slow the passage of endocytic cargoes to the PVE. Yeast apparently lacks a distinct early endosome. Thus, yeast has a simple endocytic pathway that may reflect the ancestral organization of the endomembrane system.
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Affiliation(s)
- Kasey J Day
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
| | - Jason C Casler
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
| | - Benjamin S Glick
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA.
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20
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Frankel EB, Shankar R, Moresco JJ, Yates JR, Volkmann N, Audhya A. Ist1 regulates ESCRT-III assembly and function during multivesicular endosome biogenesis in Caenorhabditis elegans embryos. Nat Commun 2017; 8:1439. [PMID: 29129923 PMCID: PMC5682282 DOI: 10.1038/s41467-017-01636-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/03/2017] [Indexed: 12/23/2022] Open
Abstract
Degradation of most integral membrane proteins is directed by the endosomal sorting complex required for transport (ESCRT) machinery, which selectively targets ubiquitin-modified cargoes into intralumenal vesicles (ILVs) within multivesicular endosomes (MVEs). To better understand the mechanisms underlying ESCRT-mediated formation of ILVs, we exploited the rapid, de novo biogenesis of MVEs during the oocyte-to-embryo transition in C. elegans. In contrast to previous models suggesting that ILVs form individually, we demonstrate that they remain tethered to one another subsequent to internalization, arguing that they bud continuously from stable subdomains. In addition, we show that membrane bending and ILV formation are directed specifically by the ESCRT-III complex in vivo in a manner regulated by Ist1, which promotes ESCRT-III assembly and inhibits the incorporation of upstream ESCRT components into ILVs. Our findings underscore essential actions for ESCRT-III in membrane remodeling, cargo selection, and cargo retention, which act repetitively to maximize the rate of ILV formation.
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Affiliation(s)
- E B Frankel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA
| | - Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA
| | - James J Moresco
- The Scripps Research Institute, 10550 North Torrey Pines Rd., Department of Chemical Physiology, La Jolla, CA, 92037, USA
| | - John R Yates
- The Scripps Research Institute, 10550 North Torrey Pines Rd., Department of Chemical Physiology, La Jolla, CA, 92037, USA
| | - Niels Volkmann
- Bioinformatics and Structural Biology Program, Sanford-Burnham Medical Research Institute, 10901N Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, 440 Henry Mall, Madison, WI, 53706, USA.
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21
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Oku M, Maeda Y, Kagohashi Y, Kondo T, Yamada M, Fujimoto T, Sakai Y. Evidence for ESCRT- and clathrin-dependent microautophagy. J Cell Biol 2017; 216:3263-3274. [PMID: 28838958 PMCID: PMC5626533 DOI: 10.1083/jcb.201611029] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 04/27/2017] [Accepted: 07/24/2017] [Indexed: 12/20/2022] Open
Abstract
Microautophagy is a mode of autophagy in which the lysosomal or vacuolar membrane invaginates and engulfs target components. Oku et al. show that, upon a diauxic shift, yeast microautophagy involves recruitment of ESCRT proteins to the vacuolar membrane, including clathrin-interacting Vps27, and uptake of lipid droplets by the vacuole. Microautophagy refers to a mode of autophagy in which the lysosomal or vacuolar membrane invaginates and directly engulfs target components. The molecular machinery of membrane dynamics driving microautophagy is still elusive. Using immunochemical monitoring of yeast vacuolar transmembrane proteins, Vph1 and Pho8, fused to fluorescent proteins, we obtained evidence showing an induction of microautophagy after a diauxic shift in the yeast Saccharomyces cerevisiae. Components of the endosomal sorting complex required for transport machinery were found to be required for this process, and the gateway protein of the machinery, Vps27, was observed to change its localization onto the vacuolar membrane after a diauxic shift. We revealed the functional importance of Vps27’s interaction with clathrin in this microautophagy that also contributed to uptake of lipid droplets into the vacuole. This study sheds light on the molecular mechanism of microautophagy, which does not require the core Atg proteins.
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Affiliation(s)
- Masahide Oku
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yuichiro Maeda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yoko Kagohashi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takeshi Kondo
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Mai Yamada
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuyoshi Sakai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan .,Research Unit for Physiological Chemistry, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan
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22
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Zhu L, Jorgensen JR, Li M, Chuang YS, Emr SD. ESCRTs function directly on the lysosome membrane to downregulate ubiquitinated lysosomal membrane proteins. eLife 2017; 6:e26403. [PMID: 28661397 PMCID: PMC5507667 DOI: 10.7554/elife.26403] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/23/2017] [Indexed: 11/23/2022] Open
Abstract
The lysosome plays an important role in maintaining cellular nutrient homeostasis. Regulation of nutrient storage can occur by the ubiquitination of certain transporters that are then sorted into the lysosome lumen for degradation. To better understand the underlying mechanism of this process, we performed genetic screens to identify components of the sorting machinery required for vacuole membrane protein degradation. These screens uncovered genes that encode a ubiquitin ligase complex, components of the PtdIns 3-kinase complex, and the ESCRT machinery. We developed a novel ubiquitination system, Rapamycin-Induced Degradation (RapiDeg), to test the sorting defects caused by these mutants. These tests revealed that ubiquitinated vacuole membrane proteins recruit ESCRTs to the vacuole surface, where they mediate cargo sorting and direct cargo delivery into the vacuole lumen. Our findings demonstrate that the ESCRTs can function at both the late endosome and the vacuole membrane to mediate cargo sorting and intra-luminal vesicle formation.
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Affiliation(s)
- Lu Zhu
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Jeff R Jorgensen
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Ming Li
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Ya-Shan Chuang
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Scott D Emr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
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23
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Arcones I, Sacristán C, Roncero C. Maintaining protein homeostasis: early and late endosomal dual recycling for the maintenance of intracellular pools of the plasma membrane protein Chs3. Mol Biol Cell 2016; 27:4021-4032. [PMID: 27798229 PMCID: PMC5156543 DOI: 10.1091/mbc.e16-04-0239] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 10/11/2016] [Accepted: 10/12/2016] [Indexed: 11/19/2022] Open
Abstract
The traffic of the PM protein Chs3 is tightly regulated by combining mechanisms independently described for Golgi-resident proteins and bona fide PM permeases. This complexity highlights the importance of maintaining both stable intracellular pools of the protein and the status of Chs3 as a model for the intracellular traffic of proteins. The major chitin synthase activity in yeast cells, Chs3, has become a paradigm in the study of the intracellular traffic of transmembrane proteins due to its tightly regulated trafficking. This includes an efficient mechanism for the maintenance of an extensive reservoir of Chs3 at the trans-Golgi network/EE, which allows for the timely delivery of the protein to the plasma membrane. Here we show that this intracellular reservoir of Chs3 is maintained not only by its efficient AP-1–mediated recycling, but also by recycling through the retromer complex, which interacts with Chs3 at a defined region in its N-terminal cytosolic domain. Moreover, the N-terminal ubiquitination of Chs3 at the plasma membrane by Rsp5/Art4 distinctly labels the protein and regulates its retromer-mediated recycling by enabling Chs3 to be recognized by the ESCRT machinery and degraded in the vacuole. Therefore the combined action of two independent but redundant endocytic recycling mechanisms, together with distinct labels for vacuolar degradation, determines the final fate of the intracellular traffic of the Chs3 protein, allowing yeast cells to regulate morphogenesis, depending on environmental constraints.
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Affiliation(s)
- Irene Arcones
- IBFG and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37007 Salamanca, Spain
| | - Carlos Sacristán
- IBFG and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37007 Salamanca, Spain
| | - Cesar Roncero
- IBFG and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37007 Salamanca, Spain
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24
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Xie Q, Chen A, Zheng W, Xu H, Shang W, Zheng H, Zhang D, Zhou J, Lu G, Li G, Wang Z. Endosomal sorting complexes required for transport-0 is essential for fungal development and pathogenicity in Fusarium graminearum. Environ Microbiol 2016; 18:3742-3757. [PMID: 26971885 DOI: 10.1111/1462-2920.13296] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/30/2016] [Accepted: 03/09/2016] [Indexed: 01/19/2023]
Abstract
Fusarium graminearum is an important plant pathogen that causes head blight of major cereal crops. The vacuolar protein sorting (Vps) protein Vps27 is a component of ESCRT-0 involved in the multivesicular body (MVB) sorting pathway during endocytosis. In this study, we investigated the function of FgVps27 using a gene replacement strategy. The FgVPS27 deletion mutant (ΔFgvps27) exhibited a reduction in growth rate, aerial hyphae formation and hydrophobicity. It also showed increased sensitivity to cell wall-damaging agents and to osmotic stresses. In addition, FgHog1, the critical component of high osmolarity glycerol response pathway, was mis-localized in the ΔFgvps27 mutant upon NaCl treatment. Furthermore, the ΔFgvps27 mutant was defective in conidial production and was unable to generate perithecium in sexual reproduction. The depletion of FgVPS27 also caused a significant reduction in virulence. Further analysis by domain-specific deletion revealed that the FYVE domain was essential for the FgVps27 function and was necessary for the proper localization of FgVps27-GFP and endocytosis. Another component of ESCRT-0, the FgVps27-interacting partner FgHse1, also played an important role in F. graminearum development and pathogenesis. Overall, our results indicate that ESCRT-0 components play critical roles in a variety of cellular and biological processes.
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Affiliation(s)
- Qiurong Xie
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ahai Chen
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wenhui Zheng
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Huaijian Xu
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wenjie Shang
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Huawei Zheng
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Dongmei Zhang
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jie Zhou
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guodong Lu
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guangpu Li
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Zonghua Wang
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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25
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Lemus L, Ribas JL, Sikorska N, Goder V. An ER-Localized SNARE Protein Is Exported in Specific COPII Vesicles for Autophagosome Biogenesis. Cell Rep 2016; 14:1710-1722. [PMID: 26876173 DOI: 10.1016/j.celrep.2016.01.047] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 11/11/2015] [Accepted: 01/13/2016] [Indexed: 12/26/2022] Open
Abstract
The de novo formation of autophagosomes for the targeting of cytosolic material to the vacuole/lysosome is upregulated upon starvation. How autophagosomes acquire membranes remains still unclear. Here, we report that, in yeast, the endoplasmic reticulum (ER)-localized Qa/t-SNARE Ufe1 has a role in autophagy. During starvation, Ufe1 is increasingly exported from the ER and targeted to intracellular sites that contain the autophagy markers Atg8 and Atg9. In addition, Ufe1 interacts with non-ER SNARE proteins implicated in autophagosome formation. Loss of Ufe1 function impairs autophagy and results in fewer and smaller autophagosomes. Unlike conventional cargo, the ER export of Ufe1 is significantly reduced in sec23-1 cells, which affects the coat protein (COP)II complex, already at the permissive temperature. Under the same conditions, sec23-1 cells are hypersensitive to starvation and deficient in autophagy. Our data suggest that ER membranes containing Ufe1 are delivered to sites of autophagosome formation in specific COPII vesicles.
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Affiliation(s)
- Leticia Lemus
- Department of Genetics, University of Seville, Avenue Reina Mercedes, s/n, 41012 Seville, Spain
| | - Juan Luis Ribas
- Centro de Investigación Tecnología e Innovación de la Universidad de Sevilla, Avenue Reina Mercedes, 41012 Seville, Spain
| | - Natalia Sikorska
- Department of Genetics, University of Seville, Avenue Reina Mercedes, s/n, 41012 Seville, Spain
| | - Veit Goder
- Department of Genetics, University of Seville, Avenue Reina Mercedes, s/n, 41012 Seville, Spain.
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26
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The AP-3 adaptor complex mediates sorting of yeast and mammalian PQ-loop-family basic amino acid transporters to the vacuolar/lysosomal membrane. Sci Rep 2015; 5:16665. [PMID: 26577948 PMCID: PMC4649669 DOI: 10.1038/srep16665] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/19/2015] [Indexed: 01/31/2023] Open
Abstract
The limiting membrane of lysosomes in animal cells and that of the vacuole in yeast
include a wide variety of transporters, but little is known about how these proteins
reach their destination membrane. The mammalian PQLC2 protein catalyzes efflux of
basic amino acids from the lysosome, and the similar Ypq1, −2, and
−3 proteins of yeast perform an equivalent function at the vacuole. We
here show that the Ypq proteins are delivered to the vacuolar membrane via the
alkaline phosphatase (ALP) trafficking pathway, which requires the AP-3 adaptor
complex. When traffic via this pathway is deficient, the Ypq proteins pass through
endosomes from where Ypq1 and Ypq2 properly reach the vacuolar membrane whereas Ypq3
is missorted to the vacuolar lumen via the multivesicular body pathway. When
produced in yeast, PQLC2 also reaches the vacuolar membrane via the ALP pathway, but
tends to sort to the vacuolar lumen if AP-3 is defective. Finally, in HeLa cells,
inhibiting the synthesis of an AP-3 subunit also impairs sorting of PQLC2 to
lysosomes. Our results suggest the existence of a conserved AP-3-dependent
trafficking pathway for proper delivery of basic amino acid exporters to the yeast
vacuole and to lysosomes of human cells.
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27
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Corrigan L, Redhai S, Leiblich A, Fan SJ, Perera SMW, Patel R, Gandy C, Wainwright SM, Morris JF, Hamdy F, Goberdhan DCI, Wilson C. BMP-regulated exosomes from Drosophila male reproductive glands reprogram female behavior. ACTA ACUST UNITED AC 2014; 206:671-88. [PMID: 25154396 PMCID: PMC4151142 DOI: 10.1083/jcb.201401072] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Male Drosophila reproductive glands secrete exosomes in a BMP-dependent manner that fuse with sperm after mating and suppress female remating. Male reproductive glands secrete signals into seminal fluid to facilitate reproductive success. In Drosophila melanogaster, these signals are generated by a variety of seminal peptides, many produced by the accessory glands (AGs). One epithelial cell type in the adult male AGs, the secondary cell (SC), grows selectively in response to bone morphogenetic protein (BMP) signaling. This signaling is involved in blocking the rapid remating of mated females, which contributes to the reproductive advantage of the first male to mate. In this paper, we show that SCs secrete exosomes, membrane-bound vesicles generated inside late endosomal multivesicular bodies (MVBs). After mating, exosomes fuse with sperm (as also seen in vitro for human prostate-derived exosomes and sperm) and interact with female reproductive tract epithelia. Exosome release was required to inhibit female remating behavior, suggesting that exosomes are downstream effectors of BMP signaling. Indeed, when BMP signaling was reduced in SCs, vesicles were still formed in MVBs but not secreted as exosomes. These results demonstrate a new function for the MVB–exosome pathway in the reproductive tract that appears to be conserved across evolution.
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Affiliation(s)
- Laura Corrigan
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Siamak Redhai
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Aaron Leiblich
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Shih-Jung Fan
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Sumeth M W Perera
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Rachel Patel
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Carina Gandy
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - S Mark Wainwright
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - John F Morris
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Freddie Hamdy
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Deborah C I Goberdhan
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
| | - Clive Wilson
- Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK
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28
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Signaling events of the Rim101 pathway occur at the plasma membrane in a ubiquitination-dependent manner. Mol Cell Biol 2014; 34:3525-34. [PMID: 25002535 DOI: 10.1128/mcb.00408-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In yeast, external alkalization and alteration in plasma membrane lipid asymmetry are sensed by the Rim101 pathway. It is currently under debate whether the signal elicited by external alkalization is transduced to downstream molecules at the plasma membrane or via endocytosis of the Rim21 sensor protein at the late endosome. We found that the downstream molecules, including arrestin-related protein Rim8, calpain-like protein Rim13, and scaffold protein Rim20, accumulated at the plasma membrane upon external alkalization and that the accumulation was dependent on Rim21. Snf7, an endosomal sorting complex required for transport (ESCRT) III subunit also essential for the Rim101 pathway, localized to the plasma membrane, in addition to the late endosome, under alkaline conditions. Snf7 at the plasma membrane but not at the late endosome was shown to be involved in Rim101 signaling. In addition, the Rim101 pathway was normally activated, even when endocytosis was severely impaired. Considering this information as a whole, we propose that Rim101 signaling proceeds at the plasma membrane. We also found that activity of the Rsp5 ubiquitin ligase was required for recruiting the downstream molecules to the plasma membrane, suggesting that ubiquitination mediates Rim101 signaling at the plasma membrane.
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29
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Cai Y, Zhuang X, Gao C, Wang X, Jiang L. The Arabidopsis Endosomal Sorting Complex Required for Transport III Regulates Internal Vesicle Formation of the Prevacuolar Compartment and Is Required for Plant Development. PLANT PHYSIOLOGY 2014; 165:1328-1343. [PMID: 24812106 PMCID: PMC4081340 DOI: 10.1104/pp.114.238378] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We have established an efficient transient expression system with several vacuolar reporters to study the roles of endosomal sorting complex required for transport (ESCRT)-III subunits in regulating the formation of intraluminal vesicles of prevacuolar compartments (PVCs)/multivesicular bodies (MVBs) in plant cells. By measuring the distributions of reporters on/within the membrane of PVC/MVB or tonoplast, we have identified dominant negative mutants of ESCRT-III subunits that affect membrane protein degradation from both secretory and endocytic pathways. In addition, induced expression of these mutants resulted in reduction in luminal vesicles of PVC/MVB, along with increased detection of membrane-attaching vesicles inside the PVC/MVB. Transgenic Arabidopsis (Arabidopsis thaliana) plants with induced expression of ESCRT-III dominant negative mutants also displayed severe cotyledon developmental defects with reduced cell size, loss of the central vacuole, and abnormal chloroplast development in mesophyll cells, pointing out an essential role of the ESCRT-III complex in postembryonic development in plants. Finally, membrane dissociation of ESCRT-III components is important for their biological functions and is regulated by direct interaction among Vacuolar Protein Sorting-Associated Protein20-1 (VPS20.1), Sucrose Nonfermenting7-1, VPS2.1, and the adenosine triphosphatase VPS4/SUPPRESSOR OF K+ TRANSPORT GROWTH DEFECT1.
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Affiliation(s)
- Yi Cai
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (Y.C., X.Z., C.G., X.W., L.J.); andChinese University of Hong Kong Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Xiaohong Zhuang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (Y.C., X.Z., C.G., X.W., L.J.); andChinese University of Hong Kong Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Caiji Gao
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (Y.C., X.Z., C.G., X.W., L.J.); andChinese University of Hong Kong Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Xiangfeng Wang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (Y.C., X.Z., C.G., X.W., L.J.); andChinese University of Hong Kong Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (Y.C., X.Z., C.G., X.W., L.J.); andChinese University of Hong Kong Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
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30
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ESCRT-0 is not required for ectopic Notch activation and tumor suppression in Drosophila. PLoS One 2014; 9:e93987. [PMID: 24718108 PMCID: PMC3981749 DOI: 10.1371/journal.pone.0093987] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 03/10/2014] [Indexed: 12/05/2022] Open
Abstract
Multivesicular endosome (MVE) sorting depends on proteins of the Endosomal Sorting Complex Required for Transport (ESCRT) family. These are organized in four complexes (ESCRT-0, -I, -II, -III) that act in a sequential fashion to deliver ubiquitylated cargoes into the internal luminal vesicles (ILVs) of the MVE. Drosophila genes encoding ESCRT-I, -II, -III components function in sorting signaling receptors, including Notch and the JAK/STAT signaling receptor Domeless. Loss of ESCRT-I, -II, -III in Drosophila epithelia causes altered signaling and cell polarity, suggesting that ESCRTs genes are tumor suppressors. However, the nature of the tumor suppressive function of ESCRTs, and whether tumor suppression is linked to receptor sorting is unclear. Unexpectedly, a null mutant in Hrs, encoding one of the components of the ESCRT-0 complex, which acts upstream of ESCRT-I, -II, -III in MVE sorting is dispensable for tumor suppression. Here, we report that two Drosophila epithelia lacking activity of Stam, the other known components of the ESCRT-0 complex, or of both Hrs and Stam, accumulate the signaling receptors Notch and Dome in endosomes. However, mutant tissue surprisingly maintains normal apico-basal polarity and proliferation control and does not display ectopic Notch signaling activation, unlike cells that lack ESCRT-I, -II, -III activity. Overall, our in vivo data confirm previous evidence indicating that the ESCRT-0 complex plays no crucial role in regulation of tumor suppression, and suggest re-evaluation of the relationship of signaling modulation in endosomes and tumorigenesis.
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Toshima JY, Nishinoaki S, Sato Y, Yamamoto W, Furukawa D, Siekhaus DE, Sawaguchi A, Toshima J. Bifurcation of the endocytic pathway into Rab5-dependent and -independent transport to the vacuole. Nat Commun 2014; 5:3498. [PMID: 24667230 DOI: 10.1038/ncomms4498] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 02/24/2014] [Indexed: 12/27/2022] Open
Abstract
The yeast Rab5 homologue, Vps21p, is known to be involved both in the vacuolar protein sorting (VPS) pathway from the trans-Golgi network to the vacuole, and in the endocytic pathway from the plasma membrane to the vacuole. However, the intracellular location at which these two pathways converge remains unclear. In addition, the endocytic pathway is not completely blocked in yeast cells lacking all Rab5 genes, suggesting the existence of an unidentified route that bypasses the Rab5-dependent endocytic pathway. Here we show that convergence of the endocytic and VPS pathways occurs upstream of the requirement for Vps21p in these pathways. We also identify a previously unidentified endocytic pathway mediated by the AP-3 complex. Importantly, the AP-3-mediated pathway appears mostly intact in Rab5-disrupted cells, and thus works as an alternative route to the vacuole/lysosome. We propose that the endocytic traffic branches into two routes to reach the vacuole: a Rab5-dependent VPS pathway and a Rab5-independent AP-3-mediated pathway.
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Affiliation(s)
- Junko Y Toshima
- 1] Faculty of Science and Engineering, Waseda University, Wakamatsu-cho, 2-2, Shinjuku-ku, Tokyo 162-8480, Japan [2] Research Center for RNA Science, RIST, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Show Nishinoaki
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Yoshifumi Sato
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Wataru Yamamoto
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Daiki Furukawa
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | | | - Akira Sawaguchi
- Department of Anatomy, University of Miyazaki Faculty of Medicine, Miyazaki 889-1692, Japan
| | - Jiro Toshima
- 1] Research Center for RNA Science, RIST, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan [2] Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
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Smardon AM, Diab HI, Tarsio M, Diakov TT, Nasab ND, West RW, Kane PM. The RAVE complex is an isoform-specific V-ATPase assembly factor in yeast. Mol Biol Cell 2013; 25:356-67. [PMID: 24307682 PMCID: PMC3907276 DOI: 10.1091/mbc.e13-05-0231] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Vacuolar H+-ATPases (V-ATPases) acidify multiple organelles, and subunit isoforms help impart organelle-specific regulation of acidification. The regulator of ATPase of vacuoles and endosomes (RAVE) complex regulates organelle acidification by promoting V-ATPase assembly. This work demonstrates that RAVE is the first identified isoform-specific V-ATPase assembly factor required for control of vacuolar acidification. The regulator of ATPase of vacuoles and endosomes (RAVE) complex is implicated in vacuolar H+-translocating ATPase (V-ATPase) assembly and activity. In yeast, rav1∆ mutants exhibit a Vma− growth phenotype characteristic of loss of V-ATPase activity only at high temperature. Synthetic genetic analysis identified mutations that exhibit a full, temperature-independent Vma− growth defect when combined with the rav1∆ mutation. These include class E vps mutations, which compromise endosomal sorting. The synthetic Vma− growth defect could not be attributed to loss of vacuolar acidification in the double mutants, as there was no vacuolar acidification in the rav1∆ mutant. The yeast V-ATPase a subunit is present as two isoforms, Stv1p in Golgi and endosomes and Vph1p in vacuoles. Rav1p interacts directly with the N-terminal domain of Vph1p. STV1 overexpression suppressed the growth defects of both rav1∆ and rav1∆vph1∆, and allowed RAVE-independent assembly of active Stv1p-containing V-ATPases in vacuoles. Mutations causing synthetic genetic defects in combination with rav1∆ perturbed the normal localization of Stv1–green fluorescent protein. We propose that RAVE is necessary for assembly of Vph1-containing V-ATPase complexes but not Stv1-containing complexes. Synthetic Vma− phenotypes arise from defects in Vph1p-containing complexes caused by rav1∆, combined with defects in Stv1p-containing V-ATPases caused by the second mutation. Thus RAVE is the first isoform-specific V-ATPase assembly factor.
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Affiliation(s)
- Anne M Smardon
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210
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Hachiro T, Yamamoto T, Nakano K, Tanaka K. Phospholipid flippases Lem3p-Dnf1p and Lem3p-Dnf2p are involved in the sorting of the tryptophan permease Tat2p in yeast. J Biol Chem 2012; 288:3594-608. [PMID: 23250744 DOI: 10.1074/jbc.m112.416263] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The type 4 P-type ATPases are flippases that generate phospholipid asymmetry in membranes. In budding yeast, heteromeric flippases, including Lem3p-Dnf1p and Lem3p-Dnf2p, translocate phospholipids to the cytoplasmic leaflet of membranes. Here, we report that Lem3p-Dnf1/2p are involved in transport of the tryptophan permease Tat2p to the plasma membrane. The lem3Δ mutant exhibited a tryptophan requirement due to the mislocalization of Tat2p to intracellular membranes. Tat2p was relocalized to the plasma membrane when trans-Golgi network (TGN)-to-endosome transport was inhibited. Inhibition of ubiquitination by mutations in ubiquitination machinery also rerouted Tat2p to the plasma membrane. Lem3p-Dnf1/2p are localized to endosomal/TGN membranes in addition to the plasma membrane. Endocytosis mutants, in which Lem3p-Dnf1/2p are sequestered to the plasma membrane, also exhibited the ubiquitination-dependent missorting of Tat2p. These results suggest that Tat2p is ubiquitinated at the TGN and missorted to the vacuolar pathway in the lem3Δ mutant. The NH(2)-terminal cytoplasmic region of Tat2p containing ubiquitination acceptor lysines interacted with liposomes containing acidic phospholipids, including phosphatidylserine. This interaction was abrogated by alanine substitution mutations in the basic amino acids downstream of the ubiquitination sites. Interestingly, a mutant Tat2p containing these substitutions was missorted in a ubiquitination-dependent manner. We propose the following model based on these results; Tat2p is not ubiquitinated when the NH(2)-terminal region is bound to membrane phospholipids, but if it dissociates from the membrane due to a low level of phosphatidylserine caused by perturbation of phospholipid asymmetry in the lem3Δ mutant, Tat2p is ubiquitinated and then transported from the TGN to the vacuole.
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Affiliation(s)
- Takeru Hachiro
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, N15 W7, Kita-ku, Sapporo 060-0815, Japan
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The endosomal protein-sorting receptor sortilin has a role in trafficking α-1 antitrypsin. Genetics 2012; 192:889-903. [PMID: 22923381 DOI: 10.1534/genetics.112.143487] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Up to 1 in 3000 individuals in the United States have α-1 antitrypsin deficiency, and the most common cause of this disease is homozygosity for the antitrypsin-Z variant (ATZ). ATZ is inefficiently secreted, resulting in protein deficiency in the lungs and toxic polymer accumulation in the liver. However, only a subset of patients suffer from liver disease, suggesting that genetic factors predispose individuals to liver disease. To identify candidate factors, we developed a yeast ATZ expression system that recapitulates key features of the disease-causing protein. We then adapted this system to screen the yeast deletion mutant collection to identify conserved genes that affect ATZ secretion and thus may modify the risk for developing liver disease. The results of the screen and associated assays indicate that ATZ is degraded in the vacuole after being routed from the Golgi. In fact, one of the strongest hits from our screen was Vps10, which can serve as a receptor for the delivery of aberrant proteins to the vacuole. Because genome-wide association studies implicate the human Vps10 homolog, sortilin, in cardiovascular disease, and because hepatic cell lines that stably express wild-type or mutant sortilin were recently established, we examined whether ATZ levels and secretion are affected by sortilin. As hypothesized, sortilin function impacts the levels of secreted ATZ in mammalian cells. This study represents the first genome-wide screen for factors that modulate ATZ secretion and has led to the identification of a gene that may modify disease severity or presentation in individuals with ATZ-associated liver disease.
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35
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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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36
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Richards A, Gow NAR, Veses V. Identification of vacuole defects in fungi. J Microbiol Methods 2012; 91:155-63. [PMID: 22902527 DOI: 10.1016/j.mimet.2012.08.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 07/30/2012] [Accepted: 08/02/2012] [Indexed: 11/25/2022]
Abstract
Fungal vacuoles are involved in a diverse range of cellular functions, participating in cellular homeostasis, degradation of intracellular components, and storage of ions and molecules. In recent years there has been a significant increase in the number of studies linking these organelles with the regulation of growth and control of cellular morphology, particularly in those fungal species able to undergo yeast-hypha morphogenetic transitions. This has contributed to the refinement of previously published protocols and the development of new techniques, particularly in the area of live-cell imaging of membrane trafficking events and vacuolar dynamics. The current review outlines recent advances in the imaging of fungal vacuoles and assays for characterization of trafficking pathways, and other physiological activities of this important cell organelle.
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Affiliation(s)
- Andrea Richards
- The Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
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37
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Peptides induce persistent signaling from endosomes by a nutrient transceptor. Nat Chem Biol 2012; 8:400-8. [PMID: 22388927 DOI: 10.1038/nchembio.910] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 12/23/2011] [Indexed: 11/09/2022]
Abstract
The yeast Gap1 transceptor mediates amino acid activation of the protein kinase A pathway and undergoes endocytic internalization following amino acid transport. We identified three specific γ-glutamyl dipeptides that cause persistent cyclic AMP-independent activation of protein kinase A, prevent Gap1 vacuolar sorting and cause Gap1 accumulation in endosomes. To our knowledge, these are the first examples of persistent agonists of a transceptor. In yeast mutants blocked in multivesicular body sorting, L-citrulline mimicked persistent signaling, further supporting that the internalized Gap1 transceptor keeps signaling. Unexpectedly, these dipeptides were transported by Gap1 and not by the regular dipeptide transporters. Their uptake was unusually sensitive to external pH and caused transient intracellular acidification. High external pH, NHA1 deletion or V-ATPase inhibition overcame the vacuolar sorting defect. Hence, this work has identified specific dipeptides that cause enhanced proton influx through the Gap1 symporter, resulting in its defective vacuolar sorting, and independently transform it into a persistently signaling transceptor.
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38
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Intracellular interactome of secreted antibody Fab fragment in Pichia pastoris reveals its routes of secretion and degradation. Appl Microbiol Biotechnol 2012; 93:2503-12. [DOI: 10.1007/s00253-012-3933-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 01/26/2012] [Accepted: 01/28/2012] [Indexed: 12/13/2022]
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Kama R, Kanneganti V, Ungermann C, Gerst JE. The yeast Batten disease orthologue Btn1 controls endosome-Golgi retrograde transport via SNARE assembly. ACTA ACUST UNITED AC 2011; 195:203-15. [PMID: 21987636 PMCID: PMC3198160 DOI: 10.1083/jcb.201102115] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The human Batten disease gene CLN3 and yeast orthologue BTN1 encode proteins of unclear function. We show that the loss of BTN1 phenocopies that of BTN2, which encodes a retromer accessory protein involved in the retrieval of specific cargo from late endosomes (LEs) to the Golgi. However, Btn1 localizes to Golgi and regulates soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor (SNARE) function to control retrograde transport. Specifically, BTN1 overexpression and deletion have opposing effects on phosphorylation of the Sed5 target membrane SNARE, on Golgi SNARE assembly, and on Golgi integrity. Although Btn1 does not interact physically with SNAREs, it regulates Sed5 phosphorylation by modulating Yck3, a palmitoylated endosomal kinase. This may involve modification of the Yck3 lipid anchor, as substitution with a transmembrane domain suppresses the deletion of BTN1 and restores trafficking. Correspondingly, deletion of YCK3 mimics that of BTN1 or BTN2 with respect to LE-Golgi retrieval. Thus, Btn1 controls retrograde sorting by regulating SNARE phosphorylation and assembly, a process that may be adversely affected in Batten Disease patients.
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Affiliation(s)
- Rachel Kama
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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40
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Vacuolar protein sorting genes regulate mat formation in Saccharomyces cerevisiae by Flo11p-dependent and -independent mechanisms. EUKARYOTIC CELL 2011; 10:1516-26. [PMID: 21908597 DOI: 10.1128/ec.05078-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Saccharomyces cerevisiae generates complex biofilms called mats on low-density (0.3%) agar plates. The mats can be morphologically divided into two regions: (i) hub, the interior region characterized by the presence of wrinkles and channels, and (ii) rim, the smooth periphery. Formation of mats depends on the adhesin Flo11p, which is also required for invasive growth, a phenotype in which the S. cerevisiae yeasts grow as chains of cells that dig into standard-density (2%) agar plates. Although both invasive growth and mat formation depend on Flo11p, mutations that perturb the multivesicular body (MVB) protein sorting pathway inhibit mat formation in a FLO11-independent manner. These mutants, represented by vps27Δ, disrupt mat formation but do not affect invasive growth, FLO11 gene or protein expression, or Flo11p localization. In contrast, an overlapping subset of MVB mutants (represented by ESCRT [endosomal sorting complex required for transport] complex genes such as VPS25) interrupt the Rim101p signal transduction cascade, which is required for FLO11 expression, and thus block both invasive growth and mat formation. In addition, this report shows that mature Flo11p is covalently associated with the cell wall and shed into the extracellular matrix of the growing mat.
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Abstract
The endosomal-sorting complex required for transport (ESCRT) apparatus has multiple ubiquitin (Ub)-binding domains and participates in a wide variety of cellular processes. Many of these ESCRT-dependent processes are keenly regulated by Ub, which serves as a lysosomal-sorting signal for membrane proteins targeted into multivesicular bodies (MVBs) and which may serve as a mediator of viral budding from the cell surface. Hints that both ESCRTs and Ub work together in the processes such as cytokinesis, transcription and autophagy are beginning to emerge. Here, we explore the relationship between ESCRTs and Ub in MVB sorting and viral budding.
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Affiliation(s)
- S Brookhart Shields
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52246, USA
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42
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Gulshan K, Moye-Rowley WS. Vacuolar import of phosphatidylcholine requires the ATP-binding cassette transporter Ybt1. Traffic 2011; 12:1257-68. [PMID: 21649806 DOI: 10.1111/j.1600-0854.2011.01228.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
ATP-binding cassette (ABC) transporters are well known for their roles as multidrug resistance determinants but also play important roles in regulation of lipid levels. In the yeast Saccharomyces cerevisiae, the plasma membrane ABC transporter proteins Pdr5 and Yor1 are required for normal rates of transport of phosphatidyethanolamine to the surface of the cell. Loss of these ABC transporters causes a defect in phospholipid asymmetry across the plasma membrane and has been linked with slowed rates of trafficking of other membrane proteins. Four ABC transporter proteins are found on the limiting membrane of the yeast vacuole and loss of one of these vacuolar ABC transporters, Ybt1, caused a major defect in the normal delivery of the phosphatidylcholine (PC) analog NBD-PC (7-nitro-2,1,3-benzoxadiazol-PC) to the lumen of the vacuole. NBD-PC accumulates on cytosolic membranes in an ybt1Δ strain. We demonstrated that Ybt1 is required to import NBD-PC into vacuoles in the presence of ATP in vitro. Loss of Ybt1 prevented vacuolar remodeling of PC analogs. Turnover of Ybt1 was reduced under conditions in which function of this vacuolar remodeling pathway was required. Our data describe a novel vacuolar route for lipid remodeling and reutilization in addition to previously described enzymatic avenues in the cytoplasm.
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Affiliation(s)
- Kailash Gulshan
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, 6-530 Bowen Science Building, University of Iowa, Iowa City, IA 52246, USA
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Lim PH, Pisat NP, Gadhia N, Pandey A, Donovan FX, Stein L, Salt DE, Eide DJ, MacDiarmid CW. Regulation of Alr1 Mg transporter activity by intracellular magnesium. PLoS One 2011; 6:e20896. [PMID: 21738593 PMCID: PMC3125163 DOI: 10.1371/journal.pone.0020896] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 05/12/2011] [Indexed: 12/15/2022] Open
Abstract
Mg homeostasis is critical to eukaryotic cells, but the contribution of Mg transporter activity to homeostasis is not fully understood. In yeast, Mg uptake is primarily mediated by the Alr1 transporter, which also allows low affinity uptake of other divalent cations such as Ni(2+), Mn(2+), Zn(2+) and Co(2+). Using Ni(2+) uptake to assay Alr1 activity, we observed approximately nine-fold more activity under Mg-deficient conditions. The mnr2 mutation, which is thought to block release of vacuolar Mg stores, was associated with increased Alr1 activity, suggesting Alr1 was regulated by intracellular Mg supply. Consistent with a previous report of the regulation of Alr1 expression by Mg supply, Mg deficiency and the mnr2 mutation both increased the accumulation of a carboxy-terminal epitope-tagged version of the Alr1 protein (Alr1-HA). However, Mg supply had little effect on ALR1 promoter activity or mRNA levels. In addition, while Mg deficiency caused a seven-fold increase in Alr1-HA accumulation, the N-terminally tagged and untagged Alr1 proteins increased less than two-fold. These observations argue that the Mg-dependent accumulation of the C-terminal epitope-tagged protein was primarily an artifact of its modification. Plasma membrane localization of YFP-tagged Alr1 was also unaffected by Mg supply, indicating that a change in Alr1 location did not explain the increased activity we observed. We conclude that variation in Alr1 protein accumulation or location does not make a substantial contribution to its regulation by Mg supply, suggesting Alr1 activity is directly regulated via as yet unknown mechanisms.
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Affiliation(s)
- Phaik Har Lim
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Nilambari P. Pisat
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Nidhi Gadhia
- Department of Pharmacology and Pharmacokinetics, Regeneron Pharmaceuticals, Inc., Tarrytown, New York, United States of America
| | - Abhinav Pandey
- Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Frank X. Donovan
- Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lauren Stein
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Wauwatosa, Wisconsin, United States of America
| | - David E. Salt
- School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - David J. Eide
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Colin W. MacDiarmid
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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44
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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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45
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Coonrod EM, Stevens TH. The yeast vps class E mutants: the beginning of the molecular genetic analysis of multivesicular body biogenesis. Mol Biol Cell 2011; 21:4057-60. [PMID: 21115849 PMCID: PMC2993735 DOI: 10.1091/mbc.e09-07-0603] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In 1992, Raymond et al. published a compilation of the 41 yeast vacuolar protein sorting (vps) mutant groups and described a large class of mutants (class E vps mutants) that accumulated an exaggerated prevacuolar endosome-like compartment. Further analysis revealed that this "class E compartment" contained soluble vacuolar hydrolases, vacuolar membrane proteins, and Golgi membrane proteins unable to recycle back to the Golgi complex, yet these class E vps mutants had what seemed to be normal vacuoles. The 13 class E VPS genes were later shown to encode the proteins that make up the complexes required for formation of intralumenal vesicles in late endosomal compartments called multivesicular bodies, and for the sorting of ubiquitinated cargo proteins into these internal vesicles for eventual delivery to the vacuole or lysosome.
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Affiliation(s)
- Emily M Coonrod
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
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46
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Martín Y, González YV, Cabrera E, Rodríguez C, Siverio JM. Npr1 Ser/Thr protein kinase links nitrogen source quality and carbon availability with the yeast nitrate transporter (Ynt1) levels. J Biol Chem 2011; 286:27225-35. [PMID: 21652715 DOI: 10.1074/jbc.m111.265116] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ynt1, the single high affinity nitrate and nitrite transporter of the yeast Hansenula polymorpha, is regulated by the quality of nitrogen sources. Preferred nitrogen sources cause Ynt1 dephosphorylation, ubiquitinylation, endocytosis, and vacuolar degradation. In contrast, under nitrogen limitation Ynt1 is phosphorylated and sorted to the plasma membrane. We show here the involvement of the Ser/Thr kinase HpNpr1 in Ynt1 phosphorylation and regulation of Ynt1 levels in response to nitrogen source quality and the availability of carbon. In Δnpr1, Ynt1 phosphorylation does not take place, although Ynt1 ubiquitin conjugates increase. As a result, in this strain Ynt1 is sorted to the vacuole, from both plasma membrane and the later biosynthetic pathway in nitrogen-free conditions and nitrate. In contrast, overexpression of NPR1 blocks down-regulation of Ynt1, increasing Ynt1 phosphorylation at Ser-244 and -246 and reducing ubiquitinylation. Furthermore, Npr1 is phosphorylated in response to the preferred nitrogen sources, and indeed it is dephosphorylated in nitrogen-free medium. Under conditions where Npr1 is phosphorylated, Ynt1 is not and vice versa. We show for the first time that carbon starvation leads to Npr1 phosphorylation, whereas Ynt1 is dephosphorylated and degraded in the vacuole. Rapamycin prevents this, indicating a possible role of the target of rapamycin signaling pathway in this process. We concluded that Npr1 plays a key role in adapting Ynt1 levels to the nitrogen quality and availability of a source of carbon.
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Affiliation(s)
- Yusé Martín
- Department of Biochemistry and Molecular Biology, Institute of Biomedical Technologies, Nitrogen Metabolism Group, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Canarias, Spain
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Structural basis for endosomal recruitment of ESCRT-I by ESCRT-0 in yeast. EMBO J 2011; 30:2130-9. [PMID: 21505419 DOI: 10.1038/emboj.2011.122] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 03/25/2011] [Indexed: 11/08/2022] Open
Abstract
The ESCRT-0 and ESCRT-I complexes coordinate the clustering of ubiquitinated cargo with intralumenal budding of the endosomal membrane, two essential steps in vacuolar/lysosomal protein sorting from yeast to humans. The 1.85-Å crystal structure of interacting regions of the yeast ESCRT-0 and ESCRT-I complexes reveals that PSDP motifs of the Vps27 ESCRT-0 subunit bind to a novel electropositive N-terminal site on the UEV domain of the ESCRT-I subunit Vps23 centred on Trp16. This novel site is completely different from the C-terminal part of the human UEV domain that binds to P(S/T)AP motifs of human ESCRT-0 and HIV-1 Gag. Disruption of the novel PSDP-binding site eliminates the interaction in vitro and blocks enrichment of Vps23 in endosome-related class E compartments in yeast cells. However, this site is non-essential for sorting of the ESCRT cargo Cps1. Taken together, these results show how a conserved motif/domain pair can evolve to use strikingly different binding modes in different organisms.
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48
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Abstract
The vacuolar proton-translocating ATPase (V-ATPase) plays a major role in organelle acidification and works together with other ion transporters to maintain pH homeostasis in eukaryotic cells. We analyzed a requirement for V-ATPase activity in protein trafficking in the yeast secretory pathway. Deficiency of V-ATPase activity caused by subunit deletion or glucose deprivation results in missorting of newly synthesized plasma membrane proteins Pma1 and Can1 directly from the Golgi to the vacuole. Vacuolar mislocalization of Pma1 is dependent on Gga adaptors although no Pma1 ubiquitination was detected. Proper cell surface targeting of Pma1 was rescued in V-ATPase-deficient cells by increasing the pH of the medium, suggesting that missorting is the result of aberrant cytosolic pH. In addition to mislocalization of the plasma membrane proteins, Golgi membrane proteins Kex2 and Vrg4 are also missorted to the vacuole upon loss of V-ATPase activity. Because the missorted cargos have distinct trafficking routes, we suggest a pH dependence for multiple cargo sorting events at the Golgi.
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Affiliation(s)
- Chunjuan Huang
- Department of Molecular, Cellular & Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Hislop JN, von Zastrow M. Role of ubiquitination in endocytic trafficking of G-protein-coupled receptors. Traffic 2010; 12:137-48. [PMID: 20854416 DOI: 10.1111/j.1600-0854.2010.01121.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Lysyl ubiquitination has long been known to target cytoplasmic proteins for proteasomal degradation, and there is now extensive evidence that ubiquitination functions in vacuolar/lysosomal targeting of membrane proteins from both the biosynthetic and endocytic pathways. G-protein-coupled receptors (GPCRs) represent the largest and most diverse family of membrane proteins, whose function is of fundamental importance both physiologically and therapeutically. In this review, we discuss the role of ubiquitination in the vacuolar/lysosomal downregulation of GPCRs through the endocytic pathway, with a primary focus on lysosomal trafficking in mammalian cells. We will summarize evidence indicating that mammalian GPCRs are regulated by ubiquitin-dependent mechanisms conserved in budding yeast, and then consider evidence for additional ubiquitin-dependent and -independent regulation that may be specific to animal cells.
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Affiliation(s)
- James N Hislop
- Department of Psychiatry, Department of Cellular and Molecular Pharmacology, UCSF School of Medicine, San Francisco, CA 94158-2140, USA
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Shahriari M, Keshavaiah C, Scheuring D, Sabovljevic A, Pimpl P, Häusler RE, Hülskamp M, Schellmann S. The AAA-type ATPase AtSKD1 contributes to vacuolar maintenance of Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:71-85. [PMID: 20663085 DOI: 10.1111/j.1365-313x.2010.04310.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The vacuole is the most prominent organelle of plant cells. Despite its importance for many physiological and developmental aspects of plant life, little is known about its biogenesis and maintenance. Here we show that Arabidopsis plants expressing a dominant-negative version of the AAA (ATPase associated with various cellular activities) ATPase AtSKD1 (SUPPRESSOR OF K+ TRANSPORT GROWTH DEFECT1) under the control of the trichome-specific GLABRA2 (GL2) promoter exhibit normal vacuolar development in early stages of trichome development. Shortly after its formation, however, the large central vacuole is fragmented and finally disappears completely. Secretion assays with amylase fused to the vacuolar sorting signal of Sporamin show that dominant-negative AtSKD1 inhibits vacuolar trafficking of the reporter that is instead secreted. In addition, trichomes expressing dominant-negative AtSKD1 frequently contain multiple nuclei. Our results suggest that AtSKD1 contributes to vacuolar protein trafficking and thereby to the maintenance of the large central vacuole of plant cells, and might play a role in cell-cycle regulation.
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Affiliation(s)
- Mojgan Shahriari
- Biozentrum Köln, University of Cologne, Zülpicher Street 47 b, 50674 Cologne, Germany
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