1
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Schultz DF, Davies BA, Payne JA, Martin CP, Minard AY, Childs BG, Zhang C, Jeganathan KB, Sturmlechner I, White TA, de Bruin A, Harkema L, Chen H, Davies MA, Jachim S, LeBrasseur NK, Piper RC, Li H, Baker DJ, van Deursen J, Billadeau DD, Katzmann DJ. Loss of HD-PTP function results in lipodystrophy, defective cellular signaling and altered lipid homeostasis. J Cell Sci 2024; 137:jcs262032. [PMID: 39155850 DOI: 10.1242/jcs.262032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 08/13/2024] [Indexed: 08/20/2024] Open
Abstract
His domain protein tyrosine phosphatase (HD-PTP; also known as PTPN23) facilitates function of the endosomal sorting complexes required for transport (ESCRTs) during multivesicular body (MVB) formation. To uncover its role in physiological homeostasis, embryonic lethality caused by a complete lack of HD-PTP was bypassed through generation of hypomorphic mice expressing reduced protein, resulting in animals that are viable into adulthood. These mice exhibited marked lipodystrophy and decreased receptor-mediated signaling within white adipose tissue (WAT), involving multiple prominent pathways including RAS/MAPK, phosphoinositide 3-kinase (PI3K)/AKT and receptor tyrosine kinases (RTKs), such as EGFR. EGFR signaling was dissected in vitro to assess the nature of defective signaling, revealing decreased trans-autophosphorylation and downstream effector activation, despite normal EGF binding. This corresponds to decreased plasma membrane cholesterol and increased lysosomal cholesterol, likely resulting from defective endosomal maturation necessary for cholesterol trafficking and homeostasis. The ESCRT components Vps4 and Hrs have previously been implicated in cholesterol homeostasis; thus, these findings expand knowledge on which ESCRT subunits are involved in cholesterol homeostasis and highlight a non-canonical role for HD-PTP in signal regulation and adipose tissue homeostasis.
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Affiliation(s)
- Destiny F Schultz
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
- Immunology Graduate Program, Mayo Clinic, Rochester, Minnesota 55905, USA
- Department of Immunology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Brian A Davies
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Johanna A Payne
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Cole P Martin
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Annabel Y Minard
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, USA
| | - Bennett G Childs
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Cheng Zhang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Karthik B Jeganathan
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Ines Sturmlechner
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen 9713 AV, The Netherlands
| | - Thomas A White
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Alain de Bruin
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen 9713 AV, The Netherlands
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht 3584 CL, The Netherlands
| | - Liesbeth Harkema
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht 3584 CL, The Netherlands
| | - Huiqin Chen
- Department of Biostatistics, Division of Quantitative Sciences, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Michael A Davies
- Department of Melanoma Medical Oncology, Division of Cancer Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Sarah Jachim
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Nathan K LeBrasseur
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Robert C Piper
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, USA
| | - Hu Li
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Darren J Baker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Jan van Deursen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
| | | | - David J Katzmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
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2
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Suzuki SW, West M, Zhang Y, Fan JS, Roberts RT, Odorizzi G, Emr SD. A role for Vps13-mediated lipid transfer at the ER-endosome contact site in ESCRT-mediated sorting. J Cell Biol 2024; 223:e202307094. [PMID: 38319250 PMCID: PMC10847051 DOI: 10.1083/jcb.202307094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 12/27/2023] [Accepted: 01/22/2024] [Indexed: 02/07/2024] Open
Abstract
Endosomes are specialized organelles that function in the secretory and endocytic protein sorting pathways. Endocytosed cell surface receptors and transporters destined for lysosomal degradation are sorted into intraluminal vesicles (ILVs) at endosomes by endosomal sorting complexes required for transport (ESCRT) proteins. The endosomes (multivesicular bodies, MVBs) then fuse with the lysosome. During endosomal maturation, the number of ILVs increases, but the size of endosomes does not decrease despite the consumption of the limiting membrane during ILV formation. Vesicle-mediated trafficking is thought to provide lipids to support MVB biogenesis. However, we have uncovered an unexpected contribution of a large bridge-like lipid transfer protein, Vps13, in this process. Here, we reveal that Vps13-mediated lipid transfer at ER-endosome contact sites is required for the ESCRT pathway. We propose that Vps13 may play a critical role in supplying lipids to the endosome, ensuring continuous ESCRT-mediated sorting during MVB biogenesis.
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Affiliation(s)
- Sho W. Suzuki
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Matthew West
- Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Yichen Zhang
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Jenny S. Fan
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Rachel T. Roberts
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Greg Odorizzi
- Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Scott D. Emr
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
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3
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Sukreet S, Rafii MS, Rissman RA. From understanding to action: Exploring molecular connections of Down syndrome to Alzheimer's disease for targeted therapeutic approach. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2024; 16:e12580. [PMID: 38623383 PMCID: PMC11016820 DOI: 10.1002/dad2.12580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 04/17/2024]
Abstract
Down syndrome (DS) is caused by a third copy of chromosome 21. Alzheimer's disease (AD) is a neurodegenerative condition characterized by the deposition of amyloid-beta (Aβ) plaques and neurofibrillary tangles in the brain. Both disorders have elevated Aβ, tau, dysregulated immune response, and inflammation. In people with DS, Hsa21 genes like APP and DYRK1A are overexpressed, causing an accumulation of amyloid and neurofibrillary tangles, and potentially contributing to an increased risk of AD. As a result, people with DS are a key demographic for research into AD therapeutics and prevention. The molecular links between DS and AD shed insights into the underlying causes of both diseases and highlight potential therapeutic targets. Also, using biomarkers for early diagnosis and treatment monitoring is an active area of research, and genetic screening for high-risk individuals may enable earlier intervention. Finally, the fundamental mechanistic parallels between DS and AD emphasize the necessity for continued research into effective treatments and prevention measures for DS patients at risk for AD. Genetic screening with customized therapy approaches may help the DS population in current clinical studies and future biomarkers.
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Affiliation(s)
- Sonal Sukreet
- Department of NeurosciencesUniversity of California‐San DiegoLa JollaCaliforniaUSA
| | - Michael S. Rafii
- Department of Neurology, Alzheimer's Therapeutic Research InstituteKeck School of Medicine of the University of Southern CaliforniaSan DiegoCaliforniaUSA
| | - Robert A. Rissman
- Department of NeurosciencesUniversity of California‐San DiegoLa JollaCaliforniaUSA
- Department Physiology and Neuroscience, Alzheimer’s Therapeutic Research InstituteKeck School of Medicine of the University of Southern CaliforniaSan DiegoCaliforniaUSA
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4
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Nagano M, Aoshima K, Shimamura H, Siekhaus DE, Toshima JY, Toshima J. Distinct role of TGN-resident clathrin adaptors for Vps21p activation in the TGN-endosome trafficking pathway. J Cell Sci 2023; 136:jcs261448. [PMID: 37539494 DOI: 10.1242/jcs.261448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023] Open
Abstract
Clathrin-mediated vesicle trafficking plays central roles in post-Golgi transport. In yeast (Saccharomyces cerevisiae), the AP-1 complex and GGA adaptors are predicted to generate distinct transport vesicles at the trans-Golgi network (TGN), and the epsin-related proteins Ent3p and Ent5p (collectively Ent3p/5p) act as accessories for these adaptors. Recently, we showed that vesicle transport from the TGN is crucial for yeast Rab5 (Vps21p)-mediated endosome formation, and that Ent3p/5p are crucial for this process, whereas AP-1 and GGA adaptors are dispensable. However, these observations were incompatible with previous studies showing that these adaptors are required for Ent3p/5p recruitment to the TGN, and thus the overall mechanism responsible for regulation of Vps21p activity remains ambiguous. Here, we investigated the functional relationships between clathrin adaptors in post-Golgi-mediated Vps21p activation. We show that AP-1 disruption in the ent3Δ5Δ mutant impaired transport of the Vps21p guanine nucleotide exchange factor Vps9p transport to the Vps21p compartment and severely reduced Vps21p activity. Additionally, GGA adaptors, the phosphatidylinositol-4-kinase Pik1p and Rab11 GTPases Ypt31p and Ypt32p were found to have partially overlapping functions for recruitment of AP-1 and Ent3p/5p to the TGN. These findings suggest a distinct role of clathrin adaptors for Vps21p activation in the TGN-endosome trafficking pathway.
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Affiliation(s)
- Makoto Nagano
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kaito Aoshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiroki Shimamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | | | - Junko Y Toshima
- School of Health Science, Tokyo University of Technology, 5-23-22 Nishikamada, Ota-ku, Tokyo 144-8535, Japan
| | - Jiro Toshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
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5
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Nakano A. The Golgi Apparatus and its Next-Door Neighbors. Front Cell Dev Biol 2022; 10:884360. [PMID: 35573670 PMCID: PMC9096111 DOI: 10.3389/fcell.2022.884360] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/28/2022] [Indexed: 12/20/2022] Open
Abstract
The Golgi apparatus represents a central compartment of membrane traffic. Its apparent architecture, however, differs considerably among species, from unstacked and scattered cisternae in the budding yeast Saccharomyces cerevisiae to beautiful ministacks in plants and further to gigantic ribbon structures typically seen in mammals. Considering the well-conserved functions of the Golgi, its fundamental structure must have been optimized despite seemingly different architectures. In addition to the core layers of cisternae, the Golgi is usually accompanied by next-door compartments on its cis and trans sides. The trans-Golgi network (TGN) can be now considered as a compartment independent from the Golgi stack. On the cis side, the intermediate compartment between the ER and the Golgi (ERGIC) has been known in mammalian cells, and its functional equivalent is now suggested for yeast and plant cells. High-resolution live imaging is extremely powerful for elucidating the dynamics of these compartments and has revealed amazing similarities in their behaviors, indicating common mechanisms conserved along the long course of evolution. From these new findings, I would like to propose reconsideration of compartments and suggest a new concept to describe their roles comprehensively around the Golgi and in the post-Golgi trafficking.
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6
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Gao J, Nicastro R, Péli-Gulli MP, Grziwa S, Chen Z, Kurre R, Piehler J, De Virgilio C, Fröhlich F, Ungermann C. The HOPS tethering complex is required to maintain signaling endosome identity and TORC1 activity. J Biophys Biochem Cytol 2022; 221:213121. [PMID: 35404387 PMCID: PMC9011323 DOI: 10.1083/jcb.202109084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/27/2022] [Accepted: 02/28/2022] [Indexed: 12/04/2022] Open
Abstract
The endomembrane system of eukaryotic cells is essential for cellular homeostasis during growth and proliferation. Previous work showed that a central regulator of growth, namely the target of rapamycin complex 1 (TORC1), binds both membranes of vacuoles and signaling endosomes (SEs) that are distinct from multivesicular bodies (MVBs). Interestingly, the endosomal TORC1, which binds membranes in part via the EGO complex, critically defines vacuole integrity. Here, we demonstrate that SEs form at a branch point of the biosynthetic and endocytic pathways toward the vacuole and depend on MVB biogenesis. Importantly, function of the HOPS tethering complex is essential to maintain the identity of SEs and proper endosomal and vacuolar TORC1 activities. In HOPS mutants, the EGO complex redistributed to the Golgi, which resulted in a partial mislocalization of TORC1. Our study uncovers that SE function requires a functional HOPS complex and MVBs, suggesting a tight link between trafficking and signaling along the endolysosomal pathway.
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Affiliation(s)
- Jieqiong Gao
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, Chemin du Musée, Fribourg, Switzerland
| | | | - Sophie Grziwa
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Zilei Chen
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Rainer Kurre
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Jacob Piehler
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
- Department of Biology/Chemistry, Biophysics Section, Osnabrück University, Osnabrück, Germany
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Chemin du Musée, Fribourg, Switzerland
| | - Florian Fröhlich
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
- Department of Biology/Chemistry, Molecular Membrane Biology Section, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
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7
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Buysse D, West M, Leih M, Odorizzi G. Bro1 binds the Vps20 subunit of ESCRT-III and promotes ESCRT-III regulation by Doa4. Traffic 2022; 23:109-119. [PMID: 34908216 PMCID: PMC8792227 DOI: 10.1111/tra.12828] [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: 06/26/2021] [Revised: 11/19/2021] [Accepted: 12/09/2021] [Indexed: 02/03/2023]
Abstract
The budding of intralumenal vesicles (ILVs) at endosomes requires membrane scission by the ESCRT-III complex. This step is negatively regulated in yeast by Doa4, the ubiquitin hydrolase that deubiquitinates transmembrane proteins sorted as cargoes into ILVs. Doa4 acts non-enzymatically to inhibit ESCRT-III membrane scission activity by directly binding the Snf7 subunit of ESCRT-III. This interaction inhibits the remodeling/disassembly of Snf7 polymers required for the ILV membrane scission reaction. Thus, Doa4 is thought to have a structural role that delays ILV budding while it also functions enzymatically to deubiquitinate ILV cargoes. In this study, we show that Doa4 binding to Snf7 in vivo is antagonized by another ESCRT-III subunit, Vps20. Doa4 is restricted from interacting with Snf7 in yeast expressing a mutant Vps20 allele that constitutively binds Doa4. This inhibitory effect of Vps20 is suppressed by overexpression of another ESCRT-III-associated protein, Bro1. We show that Bro1 binds directly to Vps20, suggesting that Bro1 has a central role in relieving the antagonistic relationship that Vps20 has toward Doa4.
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Affiliation(s)
- Dalton Buysse
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Matt West
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Mitchell Leih
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Greg Odorizzi
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA,Author for correspondence ()
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8
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Pan T, Wang Y, Jing R, Wang Y, Wei Z, Zhang B, Lei C, Qi Y, Wang F, Bao X, Yan M, Zhang Y, Zhang P, Yu M, Wan G, Chen Y, Yang W, Zhu J, Zhu Y, Zhu S, Cheng Z, Zhang X, Jiang L, Ren Y, Wan J. Post-Golgi trafficking of rice storage proteins requires the small GTPase Rab7 activation complex MON1-CCZ1. PLANT PHYSIOLOGY 2021; 187:2174-2191. [PMID: 33871646 PMCID: PMC8644195 DOI: 10.1093/plphys/kiab175] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/26/2021] [Indexed: 05/16/2023]
Abstract
Protein storage vacuoles (PSVs) are unique organelles that accumulate storage proteins in plant seeds. Although morphological evidence points to the existence of multiple PSV-trafficking pathways for storage protein targeting, the molecular mechanisms that regulate these processes remain mostly unknown. Here, we report the functional characterization of the rice (Oryza sativa) glutelin precursor accumulation7 (gpa7) mutant, which over-accumulates 57-kDa glutelin precursors in dry seeds. Cytological and immunocytochemistry studies revealed that the gpa7 mutant exhibits abnormal accumulation of storage prevacuolar compartment-like structures, accompanied by the partial mistargeting of glutelins to the extracellular space. The gpa7 mutant was altered in the CCZ1 locus, which encodes the rice homolog of Arabidopsis (Arabidopsis thaliana) CALCIUM CAFFEINE ZINC SENSITIVITY1a (CCZ1a) and CCZ1b. Biochemical evidence showed that rice CCZ1 interacts with MONENSIN SENSITIVITY1 (MON1) and that these proteins function together as the Rat brain 5 (Rab5) effector and the Rab7 guanine nucleotide exchange factor (GEF). Notably, loss of CCZ1 function promoted the endosomal localization of vacuolar protein sorting-associated protein 9 (VPS9), which is the GEF for Rab5 in plants. Together, our results indicate that the MON1-CCZ1 complex is involved in post-Golgi trafficking of rice storage protein through a Rab5- and Rab7-dependent pathway.
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Affiliation(s)
- Tian Pan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yihua Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Ruonan Jing
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yongfei Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhongyan Wei
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Binglei Zhang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Cailin Lei
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yanzhou Qi
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Fan Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiuhao Bao
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Mengyuan Yan
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yu Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Pengcheng Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Mingzhou Yu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Gexing Wan
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yu Chen
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wenkun Yang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jianping Zhu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yun Zhu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Shanshan Zhu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zhijun Cheng
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xin Zhang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ling Jiang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yulong Ren
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jianmin Wan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- Author for communication: ,
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9
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Parkinson G, Roboti P, Zhang L, Taylor S, Woodman P. His domain protein tyrosine phosphatase and Rabaptin-5 couple endo-lysosomal sorting of EGFR with endosomal maturation. J Cell Sci 2021; 134:272512. [PMID: 34657963 PMCID: PMC8627557 DOI: 10.1242/jcs.259192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/13/2021] [Indexed: 01/20/2023] Open
Abstract
His domain protein tyrosine phosphatase (HD-PTP; also known as PTPN23) collaborates with endosomal sorting complexes required for transport (ESCRTs) to sort endosomal cargo into intralumenal vesicles, forming the multivesicular body (MVB). Completion of MVB sorting is accompanied by maturation of the endosome into a late endosome, an event that requires inactivation of the early endosomal GTPase Rab5 (herein referring to generically to all isoforms). Here, we show that HD-PTP links ESCRT function with endosomal maturation. HD-PTP depletion prevents MVB sorting, while also blocking cargo from exiting Rab5-rich endosomes. HD-PTP-depleted cells contain hyperphosphorylated Rabaptin-5 (also known as RABEP1), a cofactor for the Rab5 guanine nucleotide exchange factor Rabex-5 (also known as RABGEF1), although HD-PTP is unlikely to directly dephosphorylate Rabaptin-5. In addition, HD-PTP-depleted cells exhibit Rabaptin-5-dependent hyperactivation of Rab5. HD-PTP binds directly to Rabaptin-5, between its Rabex-5- and Rab5-binding domains. This binding reaction involves the ESCRT-0/ESCRT-III binding site in HD-PTP, which is competed for by an ESCRT-III peptide. Jointly, these findings indicate that HD-PTP may alternatively scaffold ESCRTs and modulate Rabex-5–Rabaptin-5 activity, thereby helping to coordinate the completion of MVB sorting with endosomal maturation. Summary: Sorting of endocytic cargo to the multivesicular body is accompanied by endosomal maturation. Here, we provide a potential mechanism by which these two processes are linked.
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Affiliation(s)
- Gabrielle Parkinson
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Peristera Roboti
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Ling Zhang
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Sandra Taylor
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Philip Woodman
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
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10
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Wilson ZN, Buysse D, West M, Ahrens D, Odorizzi G. Vacuolar H+-ATPase dysfunction rescues intralumenal vesicle cargo sorting in yeast lacking PI(3,5)P2 or Doa4. J Cell Sci 2021; 134:jcs258459. [PMID: 34342352 PMCID: PMC8353521 DOI: 10.1242/jcs.258459] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 06/25/2021] [Indexed: 12/19/2022] Open
Abstract
Endosomes undergo a maturation process highlighted by a reduction in lumenal pH, a conversion of surface markers that prime endosome-lysosome fusion and the sequestration of ubiquitylated transmembrane protein cargos within intralumenal vesicles (ILVs). We investigated ILV cargo sorting in mutant strains of the budding yeast Saccharomyces cerevisiae that are deficient for either the lysosomal/vacuolar signaling lipid PI(3,5)P2 or the Doa4 ubiquitin hydrolase that deubiquitylates ILV cargos. Disruption of PI(3,5)P2 synthesis or Doa4 function causes a defect in sorting of a subset of ILV cargos. We show that these cargo-sorting defects are suppressed by mutations that disrupt Vph1, a subunit of vacuolar H+-ATPase (V-ATPase) complexes that acidify late endosomes and vacuoles. We further show that Vph1 dysfunction increases endosome abundance, and disrupts vacuolar localization of Ypt7 and Vps41, two crucial mediators of endosome-vacuole fusion. Because V-ATPase inhibition attenuates this fusion and rescues the ILV cargo-sorting defects in yeast that lack PI(3,5)P2 or Doa4 activity, our results suggest that the V-ATPase has a role in coordinating ILV cargo sorting with the membrane fusion machinery. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | | | | | | | - Greg Odorizzi
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
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11
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Michelini S, Barbero F, Prinelli A, Steiner P, Weiss R, Verwanger T, Andosch A, Lütz-Meindl U, Puntes VF, Drobne D, Duschl A, Horejs-Hoeck J. Gold nanoparticles (AuNPs) impair LPS-driven immune responses by promoting a tolerogenic-like dendritic cell phenotype with altered endosomal structures. NANOSCALE 2021; 13:7648-7666. [PMID: 33928963 PMCID: PMC8087175 DOI: 10.1039/d0nr09153g] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/12/2021] [Indexed: 05/15/2023]
Abstract
Dendritic cells (DCs) shape immune responses by influencing T-cell activation. Thus, they are considered both an interesting model for studying nano-immune interactions and a promising target for nano-based biomedical applications. However, the accentuated ability of nanoparticles (NPs) to interact with biomolecules may have an impact on DC function that poses an unexpected risk of unbalanced immune reactions. Here, we investigated the potential effects of gold nanoparticles (AuNPs) on DC function and the consequences for effector and memory T-cell responses in the presence of the microbial inflammatory stimulus lipopolysaccharide (LPS). Overall, we found that, in the absence of LPS, none of the tested NPs induced a DC response. However, whereas 4-, 8-, and 11 nm AuNPs did not modulate LPS-dependent immune responses, 26 nm AuNPs shifted the phenotype of LPS-activated DCs toward a tolerogenic state, characterized by downregulation of CD86, IL-12 and IL-27, upregulation of ILT3, and induction of class E compartments. Moreover, this DC phenotype was less proficient in promoting Th1 activation and central memory T-cell proliferation. Taken together, these findings support the perception that AuNPs are safe under homeostatic conditions; however, particular care should be taken in patients experiencing a current infection or disorders of the immune system.
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Affiliation(s)
- Sara Michelini
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
| | - Francesco Barbero
- Insitut Català de Nanosciència i Nanotecnologia (ICN2), UAB Campus, Bellaterra, Barcelona 08193, Spain
| | | | - Philip Steiner
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
| | - Richard Weiss
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
| | - Thomas Verwanger
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
| | - Ancuela Andosch
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
| | - Ursula Lütz-Meindl
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
| | - Victor F Puntes
- Insitut Català de Nanosciència i Nanotecnologia (ICN2), UAB Campus, Bellaterra, Barcelona 08193, Spain
| | - Damjana Drobne
- Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Albert Duschl
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
| | - Jutta Horejs-Hoeck
- Department of Biosciences, Paris-Lodron University Salzburg, Hellbrunner Str. 34, 5020 Salzburg, Austria.
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12
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The Role of Secretory Pathways in Candida albicans Pathogenesis. J Fungi (Basel) 2020; 6:jof6010026. [PMID: 32102426 PMCID: PMC7151058 DOI: 10.3390/jof6010026] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Candida albicans is a fungus that is a commensal organism and a member of the normal human microbiota. It has the ability to transition into an opportunistic invasive pathogen. Attributes that support pathogenesis include secretion of virulence-associated proteins, hyphal formation, and biofilm formation. These processes are supported by secretion, as defined in the broad context of membrane trafficking. In this review, we examine the role of secretory pathways in Candida virulence, with a focus on the model opportunistic fungal pathogen, Candida albicans.
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13
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Nagano M, Toshima JY, Siekhaus DE, Toshima J. Rab5-mediated endosome formation is regulated at the trans-Golgi network. Commun Biol 2019; 2:419. [PMID: 31754649 PMCID: PMC6858330 DOI: 10.1038/s42003-019-0670-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/29/2019] [Indexed: 01/01/2023] Open
Abstract
Early endosomes, also called sorting endosomes, are known to mature into late endosomes via the Rab5-mediated endolysosomal trafficking pathway. Thus, early endosome existence is thought to be maintained by the continual fusion of transport vesicles from the plasma membrane and the trans-Golgi network (TGN). Here we show instead that endocytosis is dispensable and post-Golgi vesicle transport is crucial for the formation of endosomes and the subsequent endolysosomal traffic regulated by yeast Rab5 Vps21p. Fittingly, all three proteins required for endosomal nucleotide exchange on Vps21p are first recruited to the TGN before transport to the endosome, namely the GEF Vps9p and the epsin-related adaptors Ent3/5p. The TGN recruitment of these components is distinctly controlled, with Vps9p appearing to require the Arf1p GTPase, and the Rab11s, Ypt31p/32p. These results provide a different view of endosome formation and identify the TGN as a critical location for regulating progress through the endolysosomal trafficking pathway.
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Affiliation(s)
- Makoto Nagano
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo, 125-8585 Japan
| | - Junko Y. Toshima
- School of Health Science, Tokyo University of Technology, 5-23-22 Nishikamada, Ota-ku, Tokyo, 144-8535 Japan
| | | | - Jiro Toshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo, 125-8585 Japan
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14
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Li J, Breker M, Graham M, Schuldiner M, Hochstrasser M. AMPK regulates ESCRT-dependent microautophagy of proteasomes concomitant with proteasome storage granule assembly during glucose starvation. PLoS Genet 2019; 15:e1008387. [PMID: 31738769 PMCID: PMC6886873 DOI: 10.1371/journal.pgen.1008387] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/02/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
The ubiquitin-proteasome system regulates numerous cellular processes and is central to protein homeostasis. In proliferating yeast and many mammalian cells, proteasomes are highly enriched in the nucleus. In carbon-starved yeast, proteasomes migrate to the cytoplasm and collect in proteasome storage granules (PSGs). PSGs dissolve and proteasomes return to the nucleus within minutes of glucose refeeding. The mechanisms by which cells regulate proteasome homeostasis under these conditions remain largely unknown. Here we show that AMP-activated protein kinase (AMPK) together with endosomal sorting complexes required for transport (ESCRTs) drive a glucose starvation-dependent microautophagy pathway that preferentially sorts aberrant proteasomes into the vacuole, thereby biasing accumulation of functional proteasomes in PSGs. The proteasome core particle (CP) and regulatory particle (RP) are regulated differently. Without AMPK, the insoluble protein deposit (IPOD) serves as an alternative site that specifically sequesters CP aggregates. Our findings reveal a novel AMPK-controlled ESCRT-mediated microautophagy mechanism in the regulation of proteasome trafficking and homeostasis under carbon starvation.
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Affiliation(s)
- Jianhui Li
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Michal Breker
- Department of Molecular Genetics, Weizmann Institute of Sciences, Rehovot, Israel
| | - Morven Graham
- Center for Cellular and Molecular Imaging, School of Medicine, Yale University, New Haven, Connecticut, United States of America
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Sciences, Rehovot, Israel
| | - Mark Hochstrasser
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
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15
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Bykov YS, Cohen N, Gabrielli N, Manenschijn H, Welsch S, Chlanda P, Kukulski W, Patil KR, Schuldiner M, Briggs JAG. High-throughput ultrastructure screening using electron microscopy and fluorescent barcoding. J Cell Biol 2019; 218:2797-2811. [PMID: 31289126 PMCID: PMC6683748 DOI: 10.1083/jcb.201812081] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 05/28/2019] [Accepted: 06/11/2019] [Indexed: 01/24/2023] Open
Abstract
Genetic screens using high-throughput fluorescent microscopes have generated large datasets, contributing many cell biological insights. Such approaches cannot tackle questions requiring knowledge of ultrastructure below the resolution limit of fluorescent microscopy. Electron microscopy (EM) reveals detailed cellular ultrastructure but requires time-consuming sample preparation, limiting throughput. Here we describe a robust method for screening by high-throughput EM. Our approach uses combinations of fluorophores as barcodes to uniquely mark each cell type in mixed populations and correlative light and EM (CLEM) to read the barcode of each cell before it is imaged by EM. Coupled with an easy-to-use software workflow for correlation, segmentation, and computer image analysis, our method, called "MultiCLEM," allows us to extract and analyze multiple cell populations from each EM sample preparation. We demonstrate several uses for MultiCLEM with 15 different yeast variants. The methodology is not restricted to yeast, can be scaled to higher throughput, and can be used in multiple ways to enable EM to become a powerful screening technique.
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Affiliation(s)
- Yury S Bykov
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Nir Cohen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Natalia Gabrielli
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Hetty Manenschijn
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Sonja Welsch
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Petr Chlanda
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Wanda Kukulski
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Kiran R Patil
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - John A G Briggs
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany .,Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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16
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Zhou F, Wu Z, Zhao M, Murtazina R, Cai J, Zhang A, Li R, Sun D, Li W, Zhao L, Li Q, Zhu J, Cong X, Zhou Y, Xie Z, Gyurkovska V, Li L, Huang X, Xue Y, Chen L, Xu H, Xu H, Liang Y, Segev N. Rab5-dependent autophagosome closure by ESCRT. J Cell Biol 2019; 218:1908-1927. [PMID: 31010855 PMCID: PMC6548130 DOI: 10.1083/jcb.201811173] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/09/2019] [Accepted: 03/29/2019] [Indexed: 01/08/2023] Open
Abstract
Zhou et al. identify the mechanism of autophagosome (AP) closure. They show that Rab5 GTPase regulates an interaction between the ESCRT subunit Snf7 and Atg17 to bring ESCRT to APs where it catalyzes AP closure. These findings highlight the convergence of the endocytic and autophagic pathways at this step. In the conserved autophagy pathway, autophagosomes (APs) engulf cellular components and deliver them to the lysosome for degradation. Before fusing with the lysosome, APs have to close via an unknown mechanism. We have previously shown that the endocytic Rab5-GTPase regulates AP closure. Therefore, we asked whether ESCRT, which catalyzes scission of vesicles into late endosomes, mediates the topologically similar process of AP sealing. Here, we show that depletion of representative subunits from all ESCRT complexes causes late autophagy defects and accumulation of APs. Focusing on two subunits, we show that Snf7 and the Vps4 ATPase localize to APs and their depletion results in accumulation of open APs. Moreover, Snf7 and Vps4 proteins complement their corresponding mutant defects in vivo and in vitro. Finally, a Rab5-controlled Atg17–Snf7 interaction is important for Snf7 localization to APs. Thus, we unravel a mechanism in which a Rab5-dependent Atg17–Snf7 interaction leads to recruitment of ESCRT to open APs where ESCRT catalyzes AP closure.
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Affiliation(s)
- Fan Zhou
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Zulin Wu
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Mengzhu Zhao
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Rakhilya Murtazina
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Juan Cai
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Ao Zhang
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Rui Li
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Dan Sun
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Wenjing Li
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Lei Zhao
- 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
| | - Jing Zhu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Technology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoxia Cong
- Department of Biochemistry and Molecular Biology, Dr. Li Dak Sam and Yap Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Yiting Zhou
- Department of Biochemistry and Molecular Biology, Dr. Li Dak Sam and Yap Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhiping Xie
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Technology, Shanghai Jiao Tong University, Shanghai, China
| | - Valeriya Gyurkovska
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Liuju Li
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Xiaoshuai Huang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Yanhong Xue
- The National Laboratory of Biomacromolecules, Chinese Academy of Sciences Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Hui Xu
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing, China
| | - Haiqian Xu
- 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
| | - Nava Segev
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL
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17
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Alfatah M, Wong JH, Nge CE, Kong KW, Low KN, Leong CY, Crasta S, Munusamy M, Chang AML, Hoon S, Ng SB, Kanagasundaram Y, Arumugam P. Hypoculoside, a sphingoid base-like compound from Acremonium disrupts the membrane integrity of yeast cells. Sci Rep 2019; 9:710. [PMID: 30679518 PMCID: PMC6345779 DOI: 10.1038/s41598-018-35979-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 11/09/2018] [Indexed: 11/15/2022] Open
Abstract
We have isolated Hypoculoside, a new glycosidic amino alcohol lipid from the fungus Acremonium sp. F2434 belonging to the order Hypocreales and determined its structure by 2D-NMR (Nuclear Magnetic Resonance) spectroscopy. Hypoculoside has antifungal, antibacterial and cytotoxic activities. Homozygous profiling (HOP) of hypoculoside in Saccharomyces cerevisiae (budding yeast) revealed that several mutants defective in vesicular trafficking and vacuolar protein transport are sensitive to hypoculoside. Staining of budding yeast cells with the styryl dye FM4-64 indicated that hypoculoside damaged the vacuolar structure. Furthermore, the propidium iodide (PI) uptake assay showed that hypoculoside disrupted the plasma membrane integrity of budding yeast cells. Interestingly, the glycosidic moiety of hypoculoside is required for its deleterious effect on growth, vacuoles and plasma membrane of budding yeast cells.
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Affiliation(s)
- Mohammad Alfatah
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore
| | - Jin Huei Wong
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore
| | - Choy Eng Nge
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore
| | - Kiat Whye Kong
- Molecular Engineering Laboratory, 61 Biopolis Drive, #03-12, Proteos, 13867, Singapore
| | - Kia Ngee Low
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore
| | - Chung Yan Leong
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore
| | - Sharon Crasta
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore
| | - Madhaiyan Munusamy
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore
| | | | - Shawn Hoon
- Molecular Engineering Laboratory, 61 Biopolis Drive, #03-12, Proteos, 13867, Singapore
| | - Siew Bee Ng
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore.
| | | | - Prakash Arumugam
- Bioinformatics Institute, 30 Biopolis Street, #07-01, Matrix, 138671, Singapore.
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18
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Karim MA, Brett CL. The Na +(K +)/H + exchanger Nhx1 controls multivesicular body-vacuolar lysosome fusion. Mol Biol Cell 2018; 29:317-325. [PMID: 29212874 PMCID: PMC5996954 DOI: 10.1091/mbc.e17-08-0496] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/07/2017] [Accepted: 11/28/2017] [Indexed: 01/12/2023] Open
Abstract
Loss-of-function mutations in human endosomal Na+(K+)/H+ exchangers (NHEs) NHE6 and NHE9 are implicated in neurological disorders including Christianson syndrome, autism, and attention deficit and hyperactivity disorder. These mutations disrupt retention of surface receptors within neurons and glial cells by affecting their delivery to lysosomes for degradation. However, the molecular basis of how these endosomal NHEs control endocytic trafficking is unclear. Using Saccharomyces cerevisiae as a model, we conducted cell-free organelle fusion assays to show that transport activity of the orthologous endosomal NHE Nhx1 is important for multivesicular body (MVB)-vacuolar lysosome fusion, the last step of endocytosis required for surface protein degradation. We find that deleting Nhx1 disrupts the fusogenicity of the MVB, not the vacuole, by targeting pH-sensitive machinery downstream of the Rab-GTPase Ypt7 needed for SNARE-mediated lipid bilayer merger. All contributing mechanisms are evolutionarily conserved offering new insight into the etiology of human disorders linked to loss of endosomal NHE function.
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19
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Karim MA, Samyn DR, Mattie S, Brett CL. Distinct features of multivesicular body-lysosome fusion revealed by a new cell-free content-mixing assay. Traffic 2017; 19:138-149. [DOI: 10.1111/tra.12543] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 11/07/2017] [Accepted: 11/09/2017] [Indexed: 01/18/2023]
Affiliation(s)
| | | | - Sevan Mattie
- Department of Biology; Concordia University; Montreal Canada
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20
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Schmidt O, Weyer Y, Fink MJ, Müller M, Weys S, Bindreither M, Teis D. Regulation of Rab5 isoforms by transcriptional and post-transcriptional mechanisms in yeast. FEBS Lett 2017; 591:2803-2815. [PMID: 28792590 PMCID: PMC5637908 DOI: 10.1002/1873-3468.12785] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 07/26/2017] [Accepted: 07/31/2017] [Indexed: 12/15/2022]
Abstract
Rab5 GTPases are master regulators of early endosome biogenesis and transport. The genome of Saccharomyces cerevisiae encodes three Rab5 proteins: Vps21, the major isoform, Ypt52 and Ypt53. Here, we show that Vps21 is the most abundant Rab5 protein and Ypt53 is the least abundant. In stressed cells, Ypt53 levels increase but never exceed that of Vps21. Its induction requires the transcription factors Crz1 and Gis1. In growing cells, the expression of Ypt53 is suppressed by post-transcriptional mechanisms mediated by the untranslated regions of the YPT53 mRNA. Based on genetic experiments, these sequences appear to stimulate deadenylation, Pat1-activated decapping and Xrn1-mediated mRNA degradation. Once this regulation is bypassed, Ypt53 protein levels surpass Vps21, and Ypt53 is sufficient to maintain endosomal function and cell growth.
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Affiliation(s)
- Oliver Schmidt
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria
| | - Yannick Weyer
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria
| | - Matthias J Fink
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria
| | - Martin Müller
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria
| | - Sabine Weys
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria
| | | | - David Teis
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria
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21
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Haag C, Pohlmann T, Feldbrügge M. The ESCRT regulator Did2 maintains the balance between long-distance endosomal transport and endocytic trafficking. PLoS Genet 2017; 13:e1006734. [PMID: 28422978 PMCID: PMC5415202 DOI: 10.1371/journal.pgen.1006734] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 05/03/2017] [Accepted: 04/04/2017] [Indexed: 01/01/2023] Open
Abstract
In highly polarised cells, like fungal hyphae, early endosomes function in both endocytosis as well as long-distance transport of various cargo including mRNA and protein complexes. However, knowledge on the crosstalk between these seemingly different trafficking processes is scarce. Here, we demonstrate that the ESCRT regulator Did2 coordinates endosomal transport in fungal hyphae of Ustilago maydis. Loss of Did2 results in defective vacuolar targeting, less processive long-distance transport and abnormal shuttling of early endosomes. Importantly, the late endosomal protein Rab7 and vacuolar protease Prc1 exhibit increased shuttling on these aberrant endosomes suggesting defects in endosomal maturation and identity. Consistently, molecular motors fail to attach efficiently explaining the disturbed processive movement. Furthermore, the endosomal mRNP linker protein Upa1 is hardly present on endosomes resulting in defects in long-distance mRNA transport. In conclusion, the ESCRT regulator Did2 coordinates precise maturation of endosomes and thus provides the correct membrane identity for efficient endosomal long-distance transport.
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Affiliation(s)
- Carl Haag
- Heinrich Heine University Düsseldorf, Institute for Microbiology, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Thomas Pohlmann
- Heinrich Heine University Düsseldorf, Institute for Microbiology, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Michael Feldbrügge
- Heinrich Heine University Düsseldorf, Institute for Microbiology, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
- * E-mail:
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22
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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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23
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Webster BM, Thaller DJ, Jäger J, Ochmann SE, Borah S, Lusk CP. Chm7 and Heh1 collaborate to link nuclear pore complex quality control with nuclear envelope sealing. EMBO J 2016; 35:2447-2467. [PMID: 27733427 DOI: 10.15252/embj.201694574] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 09/21/2016] [Accepted: 09/22/2016] [Indexed: 11/09/2022] Open
Abstract
The integrity of the nuclear envelope barrier relies on membrane remodeling by the ESCRTs, which seal nuclear envelope holes and contribute to the quality control of nuclear pore complexes (NPCs); whether these processes are mechanistically related remains poorly defined. Here, we show that the ESCRT-II/III chimera, Chm7, is recruited to a nuclear envelope subdomain that expands upon inhibition of NPC assembly and is required for the formation of the storage of improperly assembled NPCs (SINC) compartment. Recruitment to sites of NPC assembly is mediated by its ESCRT-II domain and the LAP2-emerin-MAN1 (LEM) family of integral inner nuclear membrane proteins, Heh1 and Heh2. We establish direct binding between Heh2 and the "open" forms of both Chm7 and the ESCRT-III, Snf7, and between Chm7 and Snf7. Interestingly, Chm7 is required for the viability of yeast strains where double membrane seals have been observed over defective NPCs; deletion of CHM7 in these strains leads to a loss of nuclear compartmentalization suggesting that the sealing of defective NPCs and nuclear envelope ruptures could proceed through similar mechanisms.
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Affiliation(s)
- Brant M Webster
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - David J Thaller
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Jens Jäger
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Sarah E Ochmann
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Sapan Borah
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
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24
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Ohashi Y, Soler N, García Ortegón M, Zhang L, Kirsten ML, Perisic O, Masson GR, Burke JE, Jakobi AJ, Apostolakis AA, Johnson CM, Ohashi M, Ktistakis NT, Sachse C, Williams RL. Characterization of Atg38 and NRBF2, a fifth subunit of the autophagic Vps34/PIK3C3 complex. Autophagy 2016; 12:2129-2144. [PMID: 27630019 PMCID: PMC5103362 DOI: 10.1080/15548627.2016.1226736] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The phosphatidylinositol 3-kinase Vps34 is part of several protein complexes. The structural organization of heterotetrameric complexes is starting to emerge, but little is known about organization of additional accessory subunits that interact with these assemblies. Combining hydrogen-deuterium exchange mass spectrometry (HDX-MS), X-ray crystallography and electron microscopy (EM), we have characterized Atg38 and its human ortholog NRBF2, accessory components of complex I consisting of Vps15-Vps34-Vps30/Atg6-Atg14 (yeast) and PIK3R4/VPS15-PIK3C3/VPS34-BECN1/Beclin 1-ATG14 (human). HDX-MS shows that Atg38 binds the Vps30-Atg14 subcomplex of complex I, using mainly its N-terminal MIT domain and bridges the coiled-coil I regions of Atg14 and Vps30 in the base of complex I. The Atg38 C-terminal domain is important for localization to the phagophore assembly site (PAS) and homodimerization. Our 2.2 Å resolution crystal structure of the Atg38 C-terminal homodimerization domain shows 2 segments of α-helices assembling into a mushroom-like asymmetric homodimer with a 4-helix cap and a parallel coiled-coil stalk. One Atg38 homodimer engages a single complex I. This is in sharp contrast to human NRBF2, which also forms a homodimer, but this homodimer can bridge 2 complex I assemblies.
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Affiliation(s)
- Yohei Ohashi
- a MRC Laboratory of Molecular Biology , Cambridge , United Kingdom
| | - Nicolas Soler
- a MRC Laboratory of Molecular Biology , Cambridge , United Kingdom
| | | | - Lufei Zhang
- a MRC Laboratory of Molecular Biology , Cambridge , United Kingdom
| | - Marie L Kirsten
- b European Molecular Biology Laboratory , Structural and Computational Biology Unit , Heidelberg , Germany
| | - Olga Perisic
- a MRC Laboratory of Molecular Biology , Cambridge , United Kingdom
| | - Glenn R Masson
- a MRC Laboratory of Molecular Biology , Cambridge , United Kingdom
| | - John E Burke
- b European Molecular Biology Laboratory , Structural and Computational Biology Unit , Heidelberg , Germany
| | - Arjen J Jakobi
- b European Molecular Biology Laboratory , Structural and Computational Biology Unit , Heidelberg , Germany.,c European Molecular Biology Laboratory, Hamburg Unit , Hamburg , Germany
| | | | | | - Maki Ohashi
- a MRC Laboratory of Molecular Biology , Cambridge , United Kingdom
| | | | - Carsten Sachse
- b European Molecular Biology Laboratory , Structural and Computational Biology Unit , Heidelberg , Germany
| | - Roger L Williams
- a MRC Laboratory of Molecular Biology , Cambridge , United Kingdom
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Toshima JY, Furuya E, Nagano M, Kanno C, Sakamoto Y, Ebihara M, Siekhaus DE, Toshima J. Yeast Eps15-like endocytic protein Pan1p regulates the interaction between endocytic vesicles, endosomes and the actin cytoskeleton. eLife 2016; 5. [PMID: 26914139 PMCID: PMC4775215 DOI: 10.7554/elife.10276] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 02/01/2016] [Indexed: 11/29/2022] Open
Abstract
The actin cytoskeleton plays important roles in the formation and internalization of endocytic vesicles. In yeast, endocytic vesicles move towards early endosomes along actin cables, however, the molecular machinery regulating interaction between endocytic vesicles and actin cables is poorly understood. The Eps15-like protein Pan1p plays a key role in actin-mediated endocytosis and is negatively regulated by Ark1 and Prk1 kinases. Here we show that pan1 mutated to prevent phosphorylation at all 18 threonines, pan1-18TA, displayed almost the same endocytic defect as ark1Δ prk1Δ cells, and contained abnormal actin concentrations including several endocytic compartments. Early endosomes were highly localized in the actin concentrations and displayed movement along actin cables. The dephosphorylated form of Pan1p also caused stable associations between endocytic vesicles and actin cables, and between endocytic vesicles and endosomes. Thus Pan1 phosphorylation is part of a novel mechanism that regulates endocytic compartment interactions with each other and with actin cables. DOI:http://dx.doi.org/10.7554/eLife.10276.001 The cells of all eukaryotes – including plants, animals and fungi – absorb many substances that they need from their surroundings by forming pockets around them, and then pinching off these pockets to create structures called vesicles. Clathrin is a protein that acts as a scaffold for these vesicles. Inside a eukaryotic cell, clathrin-coated vesicles first go to a structure known as an endosome, possibly by following a track made from filaments of a protein called actin. Researchers have shown previously that a yeast protein called Pan1 binds to actin filaments and helps the cells to create clathrin-coated vesicles. However it was unclear if the Pan1 protein is also important for transporting clathrin-coated vesicles to endosomes. Previous studies have also shown that adding phosphate groups on to the Pan1 protein prevents it from binding to clathrin-coated vesicles or actin filaments. Now, Toshima et al. show that a mutant version of the Pan1 protein, which cannot be modified in this way, can bind stably to both clathrin-coated vesicles and the actin filaments and connect them together. The experiments also showed that, in yeast cells that only produce the mutant version of Pan1, clathrin-coated vesicles bind stably to endosomes without the need for actin. Thus, these findings show that the addition of phosphate groups onto Pan1 is part of a mechanism that regulates the interactions between clathrin-coated vesicles, endosomes and actin filaments. Following on from this work, one future challenge is to find which proteins directly connect clathrin-coated vesicles with endosomes. It will also be important to investigate if similar mechanisms are used in the cells of mammals. DOI:http://dx.doi.org/10.7554/eLife.10276.002
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Affiliation(s)
- Junko Y Toshima
- Department of Liberal Arts, Tokyo University of Technology, Tokyo, Japan.,Research Center for RNA Science, Tokyo University of Science, Tokyo, Japan
| | - Eri Furuya
- Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Makoto Nagano
- Research Center for RNA Science, Tokyo University of Science, Tokyo, Japan.,Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Chisa Kanno
- Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Yuta Sakamoto
- Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Masashi Ebihara
- Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan
| | | | - Jiro Toshima
- Research Center for RNA Science, Tokyo University of Science, Tokyo, Japan.,Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan
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26
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Nickerson DP, Merz AJ. LUCID: A Quantitative Assay of ESCRT-Mediated Cargo Sorting into Multivesicular Bodies. Traffic 2015; 16:1318-29. [PMID: 26424513 DOI: 10.1111/tra.12331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 09/09/2015] [Accepted: 09/09/2015] [Indexed: 11/30/2022]
Abstract
Endosomes are transportation nodes, mediating selective transport of soluble and transmembrane cargos to and from the Golgi apparatus, plasma membrane and lysosomes. As endosomes mature to become multivesicular bodies (MVBs), Endosomal Sorting Complexes Required for Transport (ESCRTs) selectively incorporate transmembrane cargos into vesicles that bud into the endosome lumen. Luminal vesicles and their cargoes are targeted for destruction when MVBs fuse with lysosomes. Common assays of endosomal luminal targeting, including fluorescence microscopy and monitoring of proteolytic cargo maturation, possess significant limitations. We present a quantitative assay system called LUCID (LUCiferase reporter of Intraluminal Deposition) that monitors exposure of chimeric luciferase-cargo reporters to cytosol. Luciferase-chimera signal increases when sorting to the endosome lumen is disrupted, and silencing of signal from the chimera depends upon luminal delivery of the reporter rather than proteolytic degradation. The system presents several advantages, including rapidity, microscale operation and a high degree of reproducibility that enables detection of subtle phenotypic differences. Luciferase reporters provide linear signal over an extremely broad dynamic range, allowing analysis of reporter traffic even at anemic levels of expression. Furthermore, LUCID reports transport kinetics when applied to inducible trafficking reporters.
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Affiliation(s)
- Daniel P Nickerson
- Department of Biochemistry, University of Washington, Seattle, WA, 98195-7350, USA
| | - Alexey J Merz
- Department of Biochemistry, University of Washington, Seattle, WA, 98195-7350, USA.,Department of Physiology and Biophysics, University of Washington, Seattle, WA, 98195-7350, USA
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27
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Legent K, Liu HH, Treisman JE. Drosophila Vps4 promotes Epidermal growth factor receptor signaling independently of its role in receptor degradation. Development 2015; 142:1480-91. [PMID: 25790850 DOI: 10.1242/dev.117960] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 02/20/2015] [Indexed: 12/12/2022]
Abstract
Endocytic trafficking of signaling receptors is an important mechanism for limiting signal duration. Components of the Endosomal Sorting Complexes Required for Transport (ESCRT), which target ubiquitylated receptors to intra-lumenal vesicles (ILVs) of multivesicular bodies, are thought to terminate signaling by the epidermal growth factor receptor (EGFR) and direct it for lysosomal degradation. In a genetic screen for mutations that affect Drosophila eye development, we identified an allele of Vacuolar protein sorting 4 (Vps4), which encodes an AAA ATPase that interacts with the ESCRT-III complex to drive the final step of ILV formation. Photoreceptors are largely absent from Vps4 mutant clones in the eye disc, and even when cell death is genetically prevented, the mutant R8 photoreceptors that develop fail to recruit surrounding cells to differentiate as R1-R7 photoreceptors. This recruitment requires EGFR signaling, suggesting that loss of Vps4 disrupts the EGFR pathway. In imaginal disc cells mutant for Vps4, EGFR and other receptors accumulate in endosomes and EGFR target genes are not expressed; epistasis experiments place the function of Vps4 at the level of the receptor. Surprisingly, Vps4 is required for EGFR signaling even in the absence of Shibire, the Dynamin that internalizes EGFR from the plasma membrane. In ovarian follicle cells, in contrast, Vps4 does not affect EGFR signaling, although it is still essential for receptor degradation. Taken together, these findings indicate that Vps4 can promote EGFR activity through an endocytosis-independent mechanism.
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Affiliation(s)
- Kevin Legent
- Kimmel Center for Biology and Medicine of the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Hui Hua Liu
- Kimmel Center for Biology and Medicine of the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Jessica E Treisman
- Kimmel Center for Biology and Medicine of the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
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28
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Shideler T, Nickerson DP, Merz AJ, Odorizzi G. Ubiquitin binding by the CUE domain promotes endosomal localization of the Rab5 GEF Vps9. Mol Biol Cell 2015; 26:1345-56. [PMID: 25673804 PMCID: PMC4454180 DOI: 10.1091/mbc.e14-06-1156] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Vps9 is a guanine nucleotide exchange factor that activates Rab5 GTPases in the yeast endolysosomal pathway. Ubiquitin binding by its CUE domain is dispensable for Vps9 function. The CUE domain is shown to target Vps9 to endosomes, supporting a model in which it senses ubiquitinated transmembrane proteins trafficking in the endolysosomal pathway. Vps9 and Muk1 are guanine nucleotide exchange factors (GEFs) in Saccharomyces cerevisiae that regulate membrane trafficking in the endolysosomal pathway by activating Rab5 GTPases. We show that Vps9 is the primary Rab5 GEF required for biogenesis of late endosomal multivesicular bodies (MVBs). However, only Vps9 (but not Muk1) is required for the formation of aberrant class E compartments that arise upon dysfunction of endosomal sorting complexes required for transport (ESCRTs). ESCRT dysfunction causes ubiquitinated transmembrane proteins to accumulate at endosomes, and we demonstrate that endosomal recruitment of Vps9 is promoted by its ubiquitin-binding CUE domain. Muk1 lacks ubiquitin-binding motifs, but its fusion to the Vps9 CUE domain allows Muk1 to rescue endosome morphology, cargo trafficking, and cellular stress-tolerance phenotypes that result from loss of Vps9 function. These results indicate that ubiquitin binding by the CUE domain promotes Vps9 function in endolysosomal membrane trafficking via promotion of localization.
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Affiliation(s)
- Tess Shideler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
| | - Daniel P Nickerson
- Department of Biochemistry, University of Washington, Seattle, WA 98195-3750
| | - Alexey J Merz
- Department of Biochemistry, University of Washington, Seattle, WA 98195-3750
| | - Greg Odorizzi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
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29
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Yim YI, Park BC, Yadavalli R, Zhao X, Eisenberg E, Greene LE. The multivesicular body is the major internal site of prion conversion. J Cell Sci 2015; 128:1434-43. [PMID: 25663703 PMCID: PMC4379730 DOI: 10.1242/jcs.165472] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The conversion of the properly folded prion protein, PrPc, to its misfolded amyloid form, PrPsc, occurs as the two proteins traffic along the endocytic pathway and PrPc is exposed to PrPsc. To determine the specific site of prion conversion, we knocked down various proteins in the endocytic pathway including Rab7a, Tsg101 and Hrs (also known as HGS). PrPsc was markedly reduced in two chronically infected cell lines by preventing the maturation of the multivesicular body, a process that begins in the early endosome and ends with the sorting of cargo to the lysosome. By contrast, knocking down proteins in the retromer complex, which diverts cargo away from the multivesicular body caused an increase in PrPsc levels. These results suggest that the multivesicular body is the major site for intracellular conversion of PrPc to PrPsc.
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Affiliation(s)
- Yang-In Yim
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Bum-Chan Park
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | | | - Xiaohong Zhao
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Evan Eisenberg
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Lois E Greene
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
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30
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Arlt H, Auffarth K, Kurre R, Lisse D, Piehler J, Ungermann C. Spatiotemporal dynamics of membrane remodeling and fusion proteins during endocytic transport. Mol Biol Cell 2015; 26:1357-70. [PMID: 25657322 PMCID: PMC4454181 DOI: 10.1091/mbc.e14-08-1318] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Endosomal sorting requires consecutive steps of membrane remodeling and fusion in the course of endosomal maturation. Tracing of cargo relative to machinery reveals similar temporal localization of ESCRT and endosomal fusion machinery, which precedes the retromer complex. However, blocking fusion with the vacuole does not impair maturation. Organelles of the endolysosomal system undergo multiple fission and fusion events to combine sorting of selected proteins to the vacuole with endosomal recycling. This sorting requires a consecutive remodeling of the organelle surface in the course of endosomal maturation. Here we dissect the remodeling and fusion machinery on endosomes during the process of endocytosis. We traced selected GFP-tagged endosomal proteins relative to exogenously added fluorescently labeled α-factor on its way from the plasma membrane to the vacuole. Our data reveal that the machinery of endosomal fusion and ESCRT proteins has similar temporal localization on endosomes, whereas they precede the retromer cargo recognition complex. Neither deletion of retromer nor the fusion machinery with the vacuole affects this maturation process, although the kinetics seems to be delayed due to ESCRT deletion. Of importance, in strains lacking the active Rab7-like Ypt7 or the vacuolar SNARE fusion machinery, α-factor still proceeds to late endosomes with the same kinetics. This indicates that endosomal maturation is mainly controlled by the early endosomal fusion and remodeling machinery but not the downstream Rab Ypt7 or the SNARE machinery. Our data thus provide important further understanding of endosomal biogenesis in the context of cargo sorting.
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Affiliation(s)
- Henning Arlt
- Biochemistry Section, University of Osnabrück, 49076 Osnabrück, Germany
| | - Kathrin Auffarth
- Biochemistry Section, University of Osnabrück, 49076 Osnabrück, Germany
| | - Rainer Kurre
- Center of Advanced Light Microscopy, University of Osnabrück, 49076 Osnabrück, Germany
| | - Dominik Lisse
- Biophysics Section, University of Osnabrück, 49076 Osnabrück, Germany
| | - Jacob Piehler
- Biophysics Section, University of Osnabrück, 49076 Osnabrück, Germany
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31
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ESCRT-mediated uptake and degradation of brain-targeted α-synuclein single chain antibody attenuates neuronal degeneration in vivo. Mol Ther 2014; 22:1753-67. [PMID: 25008355 PMCID: PMC4428402 DOI: 10.1038/mt.2014.129] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 07/01/2014] [Indexed: 12/22/2022] Open
Abstract
Parkinson's disease and dementia with Lewy bodies are neurodegenerative
disorders characterized by accumulation of α-synuclein (α-syn).
Recently, single-chain fragment variables (scFVs) have been developed against
individual conformational species of α-syn. Unlike more traditional
monoclonal antibodies, these scFVs will not activate or be endocytosed by Fc
receptors. For this study, we investigated an scFV directed against oligomeric
α-syn fused to the LDL receptor-binding domain from apolipoprotein B
(apoB). The modified scFV showed enhanced brain penetration and was imported
into neuronal cells through the endosomal sorting complex required for transport
(ESCRT) pathway, leading to lysosomal degradation of α-syn aggregates.
Further analysis showed that the scFV was effective at ameliorating
neurodegenerative pathology and behavioral deficits observed in the mouse model
of dementia with Lewy bodies/Parkinson's disease. Thus, the apoB
modification had the effect of both increasing accumulation of the scFV in the
brain and directing scFV/α-syn complexes for degradation through the ESCRT
pathway, leading to improved therapeutic potential of immunotherapy.
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32
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Adell MAY, Vogel GF, Pakdel M, Müller M, Lindner H, Hess MW, Teis D. Coordinated binding of Vps4 to ESCRT-III drives membrane neck constriction during MVB vesicle formation. ACTA ACUST UNITED AC 2014; 205:33-49. [PMID: 24711499 PMCID: PMC3987140 DOI: 10.1083/jcb.201310114] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Five endosomal sorting complexes required for transport (ESCRTs) mediate the degradation of ubiquitinated membrane proteins via multivesicular bodies (MVBs) in lysosomes. ESCRT-0, -I, and -II interact with cargo on endosomes. ESCRT-II also initiates the assembly of a ringlike ESCRT-III filament consisting of Vps20, Snf7, Vps24, and Vps2. The AAA-adenosine triphosphatase Vps4 disassembles and recycles the ESCRT-III complex, thereby terminating the ESCRT pathway. A mechanistic role for Vps4 in intraluminal vesicle (ILV) formation has been unclear. By combining yeast genetics, biochemistry, and electron tomography, we find that ESCRT-III assembly on endosomes is required to induce or stabilize the necks of growing MVB ILVs. Yet, ESCRT-III alone is not sufficient to complete ILV biogenesis. Rather, binding of Vps4 to ESCRT-III, coordinated by interactions with Vps2 and Snf7, is coupled to membrane neck constriction during ILV formation. Thus, Vps4 not only recycles ESCRT-III subunits but also cooperates with ESCRT-III to drive distinct membrane-remodeling steps, which lead to efficient membrane scission at the end of ILV biogenesis in vivo.
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Affiliation(s)
- Manuel Alonso Y Adell
- Division of Cell Biology and 2 Division of Clinical Biochemistry, Biocenter; and 3 Division of Histology and Embryology; Innsbruck Medical University, Innsbruck 6020, Austria
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33
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Govindaraghavan M, McGuire Anglin SL, Shen KF, Shukla N, De Souza CP, Osmani SA. Identification of interphase functions for the NIMA kinase involving microtubules and the ESCRT pathway. PLoS Genet 2014; 10:e1004248. [PMID: 24675878 PMCID: PMC3967960 DOI: 10.1371/journal.pgen.1004248] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 02/03/2014] [Indexed: 12/11/2022] Open
Abstract
The Never in Mitosis A (NIMA) kinase (the founding member of the Nek family of kinases) has been considered a mitotic specific kinase with nuclear restricted roles in the model fungus Aspergillus nidulans. By extending to A. nidulans the results of a synthetic lethal screen performed in Saccharomyces cerevisiae using the NIMA ortholog KIN3, we identified a conserved genetic interaction between nimA and genes encoding proteins of the Endosomal Sorting Complex Required for Transport (ESCRT) pathway. Absence of ESCRT pathway functions in combination with partial NIMA function causes enhanced cell growth defects, including an inability to maintain a single polarized dominant cell tip. These genetic insights suggest NIMA potentially has interphase functions in addition to its established mitotic functions at nuclei. We therefore generated endogenously GFP-tagged NIMA (NIMA-GFP) which was fully functional to follow its interphase locations using live cell spinning disc 4D confocal microscopy. During interphase some NIMA-GFP locates to the tips of rapidly growing cells and, when expressed ectopically, also locates to the tips of cytoplasmic microtubules, suggestive of non-nuclear interphase functions. In support of this, perturbation of NIMA function either by ectopic overexpression or through partial inactivation results in marked cell tip growth defects with excess NIMA-GFP promoting multiple growing cell tips. Ectopic NIMA-GFP was found to locate to the plus ends of microtubules in an EB1 dependent manner, while impairing NIMA function altered the dynamic localization of EB1 and the cytoplasmic microtubule network. Together, our genetic and cell biological analyses reveal novel non-nuclear interphase functions for NIMA involving microtubules and the ESCRT pathway for normal polarized fungal cell tip growth. These insights extend the roles of NIMA both spatially and temporally and indicate that this conserved protein kinase could help integrate cell cycle progression with polarized cell growth.
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Affiliation(s)
- Meera Govindaraghavan
- Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | | | - Kuo-Fang Shen
- Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Nandini Shukla
- Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, United States of America
| | - Colin P. De Souza
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Stephen A. Osmani
- Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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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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Schuh AL, Audhya A. The ESCRT machinery: from the plasma membrane to endosomes and back again. Crit Rev Biochem Mol Biol 2014; 49:242-61. [PMID: 24456136 DOI: 10.3109/10409238.2014.881777] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The manipulation and reorganization of lipid bilayers are required for diverse cellular processes, ranging from organelle biogenesis to cytokinetic abscission, and often involves transient membrane disruption. A set of membrane-associated proteins collectively known as the endosomal sorting complex required for transport (ESCRT) machinery has been implicated in membrane scission steps, which transform a single, continuous bilayer into two distinct bilayers, while simultaneously segregating cargo throughout the process. Components of the ESCRT pathway, which include 5 distinct protein complexes and an array of accessory factors, each serve discrete functions. This review focuses on the molecular mechanisms by which the ESCRT proteins facilitate cargo sequestration and membrane remodeling and highlights their unique roles in cellular homeostasis.
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Affiliation(s)
- Amber L Schuh
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health , Madison, WI , USA
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Balderhaar HJK, Ungermann C. CORVET and HOPS tethering complexes - coordinators of endosome and lysosome fusion. J Cell Sci 2013; 126:1307-16. [PMID: 23645161 DOI: 10.1242/jcs.107805] [Citation(s) in RCA: 372] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Protein and lipid transport along the endolysosomal system of eukaryotic cells depends on multiple fusion and fission events. Over the past few years, the molecular constituents of both fission and fusion machineries have been identified. Here, we focus on the mechanism of membrane fusion at endosomes, vacuoles and lysosomes, and in particular on the role of the two homologous tethering complexes called CORVET and HOPS. Both complexes are heterohexamers; they share four subunits, interact with Rab GTPases and soluble NSF attachment protein receptors (SNAREs) and can tether membranes. Owing to the presence of specific subunits, CORVET is a Rab5 effector complex, whereas HOPS can bind efficiently to late endosomes and lysosomes through Rab7. Based on the recently described overall structure of the HOPS complex and a number of in vivo and in vitro analyses, important insights into their function have been obtained. Here, we discuss the general function of both complexes in yeast and in metazoan cells in the context of endosomal biogenesis and maturation.
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Affiliation(s)
- Henning J kleine Balderhaar
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry Section, Barbarastrasse 13, 49076 Osnabrück, Germany
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Johnston DA, Tapia AL, Eberle KE, Palmer GE. Three prevacuolar compartment Rab GTPases impact Candida albicans hyphal growth. EUKARYOTIC CELL 2013; 12:1039-50. [PMID: 23709183 PMCID: PMC3697461 DOI: 10.1128/ec.00359-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 05/20/2013] [Indexed: 11/20/2022]
Abstract
Disruption of vacuolar biogenesis in the pathogenic yeast Candida albicans causes profound defects in polarized hyphal growth. However, the precise vacuolar pathways involved in yeast-hypha differentiation have not been determined. Previously we focused on Vps21p, a Rab GTPase involved in directing vacuolar trafficking through the late endosomal prevacuolar compartment (PVC). Herein, we identify two additional Vps21p-related GTPases, Ypt52p and Ypt53p, that colocalize with Vps21p and can suppress the hyphal defects of the vps21Δ/Δ mutant. Phenotypic analysis of gene deletion strains revealed that loss of both VPS21 and YPT52 causes synthetic defects in endocytic trafficking to the vacuole, as well as delivery of the virulence-associated vacuolar membrane protein Mlt1p from the Golgi compartment. Transcription of all three GTPase-encoding genes is increased under hyphal growth conditions, and overexpression of the transcription factor Ume6p is sufficient to increase the transcription of these genes. While only the vps21Δ/Δ single mutant has hyphal growth defects, these were greatly exacerbated in a vps21Δ/Δ ypt52Δ/Δ double mutant. On the basis of relative expression levels and phenotypic analysis of gene deletion strains, Vps21p is the most important of the three GTPases, followed by Ypt52p, while Ypt53p has an only marginal impact on C. albicans physiology. Finally, disruption of a nonendosomal AP-3-dependent vacuolar trafficking pathway in the vps21Δ/Δ ypt52Δ/Δ mutant, further exacerbated the stress and hyphal growth defects. These findings underscore the importance of membrane trafficking through the PVC in sustaining the invasive hyphal growth form of C. albicans.
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Affiliation(s)
- Douglas A Johnston
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, School of Medicine, New Orleans, Louisiana, USA
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Paulsel AL, Merz AJ, Nickerson DP. Vps9 family protein Muk1 is the second Rab5 guanosine nucleotide exchange factor in budding yeast. J Biol Chem 2013; 288:18162-71. [PMID: 23612966 DOI: 10.1074/jbc.m113.457069] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
VPS9 domains can act as guanosine nucleotide exchange factors (GEFs) against small G proteins of the Rab5 family. Saccharomyces cerevisiae vps9Δ mutants have trafficking defects considerably less severe than multiple deletions of the three cognate Rab5 paralogs (Vps21, Ypt52, and Ypt53). Here, we show that Muk1, which also contains a VPS9 domain, acts as a second GEF against Vps21, Ypt52, and Ypt53. Muk1 is partially redundant with Vps9 in vivo, with vps9Δ muk1Δ double mutant cells displaying hypersensitivity to temperature and ionic stress, as well as profound impairments in endocytic and Golgi endosome trafficking, including defects in sorting through the multivesicular body. Cells lacking both Vps9 and Muk1 closely phenocopy double and triple knock-out strains lacking Rab5 paralogs. Microscopy and overexpression experiments demonstrate that Vps9 and Muk1 have distinct localization determinants. These experiments establish Muk1 as the second Rab5 GEF in budding yeast.
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Affiliation(s)
- Andrew L Paulsel
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350, USA
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The CORVET complex promotes tethering and fusion of Rab5/Vps21-positive membranes. Proc Natl Acad Sci U S A 2013; 110:3823-8. [PMID: 23417307 DOI: 10.1073/pnas.1221785110] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Membrane fusion along the endocytic pathway occurs in a sequence of tethering, docking, and fusion. At endosomes and vacuoles, the CORVET (class C core vacuole/endosome tethering) and HOPS (homotypic fusion and vacuole protein sorting) tethering complexes require their organelle-specific Rabs for localization and function. Until now, despite the absence of experimental evidence, it has been assumed that CORVET is a membrane-tethering factor. To test this theory and understand the mechanistic analogies with the HOPS complex, we set up an in vitro system, and establish CORVET as a bona-fide tether for Vps21-positive endosome/vacuole membranes. Purified CORVET binds to SNAREs and Rab5/Vps21-GTP. We then demonstrate that purified CORVET can specifically tether Vps21-positive membranes. Tethering via CORVET is dose-dependent, stimulated by the GEF Vps9, and inhibited by Msb3, the Vps21-GAP. Moreover, CORVET supports fusion of isolated membranes containing Vps21. In agreement with its role as a tether, overexpressed CORVET drives Vps21, but not the HOPS-specific Ypt7 into contact sites between vacuoles, which likely represent vacuole-associated endosomes. We therefore conclude that CORVET is a tethering complex that promotes fusion of Rab5-positive membranes and thus facilitates receptor down-regulation and recycling at the late endosome.
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40
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Cabrera M, Arlt H, Epp N, Lachmann J, Griffith J, Perz A, Reggiori F, Ungermann C. Functional separation of endosomal fusion factors and the class C core vacuole/endosome tethering (CORVET) complex in endosome biogenesis. J Biol Chem 2012; 288:5166-75. [PMID: 23264632 DOI: 10.1074/jbc.m112.431536] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Transport along the endolysosomal system requires multiple fusion events at early and late endosomes. Deletion of several endosomal fusion factors, including the Vac1 tether and the Class C core vacuole/endosome tethering (CORVET) complex-specific subunits Vps3 and Vps8, results in a class D vps phenotype. As these mutants have an apparently similar defect in endosomal transport, we asked whether CORVET and Vac1 could still act in distinct tethering reactions. Our data reveal that CORVET mutants can be rescued by Vac1 overexpression in the endocytic pathway but not in CPY or Cps1 sorting to the vacuole. Moreover, when we compared the ultrastructure, CORVET mutants were most similar to deletions of the Rab Vps21 and its guanine nucleotide exchange factor Vps9 and different from vac1 deletion, indicating separate functions. Likewise, CORVET still localized to endosomes even in the absence of Vac1, whereas Vac1 localization became diffuse in CORVET mutants. Importantly, CORVET localization requires the Rab5 homologs Vps21 and Ypt52, whereas Vac1 localization is strictly Vps21-dependent. In this context, we also uncover that Muk1 can compensate for loss of Vps9 in CORVET localization, indicating that two Rab5 guanine nucleotide exchange factors operate in the endocytic pathway. Overall, our study reveals a unique role of CORVET in the sorting of biosynthetic cargo to the vacuole/lysosome.
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Affiliation(s)
- Margarita Cabrera
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastr 13, 49076 Osnabrück, Germany.
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Nickerson DP, Russell MRG, Lo SY, Chapin HC, Milnes J, Merz AJ. Termination of isoform-selective Vps21/Rab5 signaling at endolysosomal organelles by Msb3/Gyp3. Traffic 2012; 13:1411-1428. [PMID: 22748138 DOI: 10.1111/j.1600-0854.2012.01390.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 06/26/2012] [Accepted: 07/02/2012] [Indexed: 12/11/2022]
Abstract
Traffic through endosomes and lysosomes is controlled by small G-proteins of the Rab5 and Rab7 families. Like humans, Saccharomyces cerevisiae has three Rab5s (Vps21, Ypt52 and Ypt53) and one Rab7 (Ypt7). Here, we elucidate the functional roles and regulation of the yeast Rab5s. Using GFP-tagged cargoes, a novel quantitative multivesicular body (MVB) sorting assay, and electron microscopy, we show that MVB biogenesis and thus MVB cargo sorting is severely impaired in vps21Δ ypt52Δ double mutants. Ypt53, the third Rab5 paralog, is hardly expressed during normal growth but its transcription is strongly induced by cellular stress through the calcineurin-Crz1 pathway. The requirement for Rab5 activity in stress tolerance facilitated identification of Msb3/Gyp3 as the principal Rab5 GAP (GTPase accelerating protein). In vitro GAP assays verified that Vps21 is a preferred Gyp3 target. Moreover, we demonstrate that Gyp3 spatially restricts active Vps21 to intermediate endosomal compartments by preventing Vps21 accumulation on lysosomal vacuoles. Gyp3, therefore, operates as a compartmental insulator that helps to define the spatial domain of Vps21 signaling in the endolysosomal pathway.
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Affiliation(s)
- Daniel P Nickerson
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Matthew R G Russell
- Department of Molecular, Cell and Developmental Biology University of Colorado, Boulder CO 80309-0347
| | - Shing-Yeng Lo
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Hannah C Chapin
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Joshua Milnes
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
| | - Alexey J Merz
- Department of Biochemistry University of Washington School of Medicine, Seattle WA 98195-3750
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