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Qu M, Liu X, Wang X, Li Z, Zhou L, Li H. Palmitoylation of vacuole membrane protein 1 promotes small extracellular vesicle secretion via interaction with ALIX and influences intercellular communication. Cell Commun Signal 2024; 22:150. [PMID: 38403678 PMCID: PMC10895845 DOI: 10.1186/s12964-024-01529-6] [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: 10/19/2023] [Accepted: 02/13/2024] [Indexed: 02/27/2024] Open
Abstract
BACKGROUND Small extracellular vesicles (EVs), exemplified by exosomes, mediate intercellular communication by transporting proteins, mRNAs, and miRNAs. Post-translational modifications are involved in controlling small EV secretion process. However, whether palmitoylation regulates small EV secretion, remains largely unexplored. METHODS Vacuole Membrane Protein 1 (VMP1) was testified to be S-palmitoylated by Palmitoylation assays. VMP1 mutant plasmids were constructed to screen out the exact palmitoylation sites. Small EVs were isolated, identified and compared between wild-type VMP1 or mutant VMP1 transfected cells. Electron microscope and immunofluorescence were used to detect multivesicular body (MVB) number and morphology change when VMP1 was mutated. Immunoprecipitation and Mass spectrum were adopted to identify the protein that interacted with palmitoylated VMP1, while knock down experiment was used to explore the function of targeted protein ALIX. Taking human Sertoli cells (SCs) and human spermatogonial stem cell like cells (SSCLCs) as a model of intercellular communication, SSCLC maintenance was detected by flow cytometry and qPCR at 12 days of differentiation. In vivo, mouse model was established by intraperitoneal injection with palmitoylation inhibitor, 2-bromopalmitate (2BP) for 3 months. RESULTS VMP1 was identified to be palmitoylated at cysteine 263,278 by ZDHHC3. Specifically, palmitoylation of VMP1 regulated its subcellular location and enhanced the amount of small EV secretion. Mutation of VMP1 palmitoylation sites interfered with the morphology and biogenesis of MVBs through suppressing intraluminal vesicle formation. Furthermore, inhibition of VMP1 palmitoylation impeded small EV secretion by affecting the interaction of VMP1 with ALIX, an accessory protein of the ESCRT machinery. Taking SCs and SSCLCs as a model of intercellular communication, we discovered VMP1 palmitoylation in SCs was vital to the growth status of SSCLCs in a co-culture system. Inhibition of VMP1 palmitoylation caused low self-maintenance, increased apoptosis, and decreased proliferation rate of SSCLCs. In vivo, intraperitoneal injection of 2BP inhibited VMP1 palmitoylation and exosomal marker expression in mouse testes, which were closely associated with the level of spermatogenic cell apoptosis and proliferation. CONCLUSIONS Our study revealed a novel mechanism for small EV secretion regulated by VMP1 palmitoylation in Sertoli cells, and demonstrated its pivotal role in intercellular communication and SSC niche.
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Affiliation(s)
- Mengyuan Qu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
- The Reproduction Medical Center, The Third Affiliated Hospital of Shenzhen University (Luohu Hospital), 47 Youyi Road, Shenzhen, 518000, Guangdong, China.
| | - Xinyu Liu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Xiaotong Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
- The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zili Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Liquan Zhou
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
| | - Honggang Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
- Wuhan Huake Reproductive Medicine Hospital, Wuhan, China.
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Mollereau B, Hayflick SJ, Escalante R, Mauthe M, Papandreou A, Iuso A, Celle M, Aniorte S, Issa AR, Lasserre JP, Lesca G, Thobois S, Burger P, Walter L. A burning question from the first international BPAN symposium: is restoration of autophagy a promising therapeutic strategy for BPAN? Autophagy 2023; 19:3234-3239. [PMID: 37565733 PMCID: PMC10621268 DOI: 10.1080/15548627.2023.2247314] [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: 01/27/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023] Open
Abstract
Beta-propeller protein-associated neurodegeneration (BPAN) is a rare neurodegenerative disease associated with severe cognitive and motor deficits. BPAN pathophysiology and phenotypic spectrum are still emerging due to the fact that mutations in the WDR45 (WD repeat domain 45) gene, a regulator of macroautophagy/autophagy, were only identified a decade ago. In the first international symposium dedicated to BPAN, which was held in Lyon, France, a panel of international speakers, including several researchers from the autophagy community, presented their work on human patients, cellular and animal models, carrying WDR45 mutations and their homologs. Autophagy researchers found an opportunity to explore the defective function of autophagy mechanisms associated with WDR45 mutations, which underlie neuronal dysfunction and early death. Importantly, BPAN is one of the few human monogenic neurological diseases targeting a regulator of autophagy, which raises the possibility that it is a relevant model to directly assess the roles of autophagy in neurodegeneration and to develop autophagy restorative therapeutic strategies for more common disorders.Abbreviations: ATG: autophagy related; BPAN: beta-propeller protein-associated neurodegeneration; ER: endoplasmic reticulum; KO: knockout; NBIA: neurodegeneration with brain iron accumulation; PtdIns3P: phosphatidylinositol-3-phosphate; ULK1: unc-51 like autophagy activating kinase 1; WDR45: WD repeat domain 45; WIPI: WD repeat domain, phosphoinositide interacting.
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Affiliation(s)
- Bertrand Mollereau
- Laboratory of Biology and Modelling of the Cell, ENS of Lyon, University of Lyon, University of Claude Bernard Lyon 1, CNRS UMR 5239, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Lyon, France
| | - Susan J Hayflick
- Departments of Molecular and Medical Genetics, Pediatrics, and Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Ricardo Escalante
- Instituto de Investigaciones Biomédicas Alberto Sols. CSIC-UAM, Madrid, Spain
| | - Mario Mauthe
- Department of Biomedical Sciences of Cells & Systems, Molecular Cell Biology Section, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Apostolos Papandreou
- Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, University College London Great Ormond Street Institute of Child Health, London, UK
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Arcangela Iuso
- Institute of Human Genetics, Technische Universität München, Munich, Germany
- Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Marion Celle
- Laboratory of Biology and Modelling of the Cell, ENS of Lyon, University of Lyon, University of Claude Bernard Lyon 1, CNRS UMR 5239, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Lyon, France
| | - Sahra Aniorte
- Laboratory of Biology and Modelling of the Cell, ENS of Lyon, University of Lyon, University of Claude Bernard Lyon 1, CNRS UMR 5239, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Lyon, France
| | - Abdul Raouf Issa
- Laboratory of Biology and Modelling of the Cell, ENS of Lyon, University of Lyon, University of Claude Bernard Lyon 1, CNRS UMR 5239, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Lyon, France
| | - Jean Paul Lasserre
- Laboratory of NRGEN, Univ. Bordeaux, CNRS, INCIA, UMR 5287, Bordeaux, France
| | - Gaetan Lesca
- Service de Génétique, Hospices Civils de Lyon, Lyon, France
- Institut Neuromyogene, Laboratoire Physiopathologie et Génétique du Neurone et du Muscle, CNRS UMR 5261-INSERM U1315, Université de Lyon - Université Claude Bernard Lyon 1, Lyon, France
| | - Stéphane Thobois
- Service de Neurologie C, Movement disorders unit, Hopital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, Bron, France
- Institut des Sciences Cognitives Marc Jeannerod, UMR 5229, CNRS, Bron, France
- Faculté de Médecine et de Maieutique Charles Mérieux, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Pauline Burger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, INSERM U1258, CNRS UMR7104, Illkirch, France
| | - Ludivine Walter
- Laboratory of Biology and Modelling of the Cell, ENS of Lyon, University of Lyon, University of Claude Bernard Lyon 1, CNRS UMR 5239, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Lyon, France
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Hama Y, Morishita H, Mizushima N. Regulation of ER-derived membrane dynamics by the DedA domain-containing proteins VMP1 and TMEM41B. EMBO Rep 2022; 23:e53894. [PMID: 35044051 PMCID: PMC8811646 DOI: 10.15252/embr.202153894] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/30/2021] [Accepted: 12/23/2021] [Indexed: 02/05/2023] Open
Abstract
The endoplasmic reticulum (ER) is a central hub for the biogenesis of various organelles and lipid-containing structures. Recent studies suggest that vacuole membrane protein 1 (VMP1) and transmembrane protein 41B (TMEM41B), multispanning ER membrane proteins, regulate the formation of many of these ER-derived structures, including autophagosomes, lipid droplets, lipoproteins, and double-membrane structures for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. VMP1 and TMEM41B possess a DedA domain that is widely distributed not only in eukaryotes but also in prokaryotes and predicted to adopt a characteristic structure containing two reentrant loops. Furthermore, recent studies show that both proteins have lipid scrambling activity. Based on these findings, the potential roles of VMP1 and TMEM41B in the dynamic remodeling of ER membranes and the biogenesis of ER-derived structures are discussed.
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Affiliation(s)
- Yutaro Hama
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
| | - Hideaki Morishita
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
- Department of PhysiologyGraduate School of MedicineJuntendo UniversityTokyoJapan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
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Xu X, Cai W, Cai P, Zhang L, Yao H, Zhang T, Shen H, Chen S. Prognostic Nomogram for Acute Myeloid Leukemia Patients With Biallelic CEBPA Mutations. Front Oncol 2021; 11:628248. [PMID: 34513657 PMCID: PMC8427751 DOI: 10.3389/fonc.2021.628248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 07/15/2021] [Indexed: 12/21/2022] Open
Abstract
Adult acute myeloid leukemia (AML) patients with biallelic mutations of CEBPA (biCEBPA) displays a favorable clinical outcome, and is defined as a unique entity in the 2016 World Health Organization classification. However, due to the intrinsic characteristics of the mutation, existence of co-occurring mutations and diversified gene expression signature, the prognosis of these patients needs to be analyzed in a more systematic way. In this study we evaluated the genetic characteristics and clinical outcome in a cohort of 137 biCEBPA AML cases, and proposed a prognostic nomogram to predict the overall survival (OS) of based on the clinical variables selected by multivariate Cox regression model in training cohort, including age, white blood cell count, co-existence of DNMT3A and CSF3R mutation and whether patients could achieve complete remission after induction therapy. The area under the receiver operating characteristic (ROC) curves for 3 and 5-year OS were 0.833 and 0.863, respectively. RNA sequencing of 4 relapsed patients showed that over-expression of VMP1 was an indicator of poor prognosis of biCEBPA AML patients. In conclusion, this prognostic nomogram might provide a more accurate prediction of the clinical outcomes of biCEBPA AML patients.
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Affiliation(s)
- Xiaoyu Xu
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China.,Institute of Blood and Marrow Transplantation, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Wenzhi Cai
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China
| | - Ping Cai
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China.,Department of Hematology, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, China
| | - Ling Zhang
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China.,Institute of Blood and Marrow Transplantation, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Hong Yao
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China.,Institute of Blood and Marrow Transplantation, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Tongtong Zhang
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China
| | - Hongjie Shen
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China
| | - Suning Chen
- National Clinical Research Center for Hematologic Diseases, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, China.,Institute of Blood and Marrow Transplantation, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
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Tornero-Écija A, Tábara LC, Bueno-Arribas M, Antón-Esteban L, Navarro-Gómez C, Sánchez I, Vincent O, Escalante R. A Dictyostelium model for BPAN disease reveals a functional relationship between the WDR45/WIPI4 homolog Wdr45l and Vmp1 in the regulation of autophagy-associated PtdIns3P and ER stress. Autophagy 2021; 18:661-677. [PMID: 34328055 PMCID: PMC9037511 DOI: 10.1080/15548627.2021.1953262] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PROPPINs are conserved PtdIns3P-binding proteins required for autophagosome biogenesis that fold into a characteristic group of seven-bladed beta-propellers. Mutations in WDR45/WIPI4, a human member of this family, lead to BPAN, a rare form of neurodegeneration. We have generated mutants for the two PROPPIN proteins present in the model system Dictyostelium discoideum (Atg18 and Wdr45l) and characterized their function. Lack of Wdr45l greatly impairs autophagy, while Atg18 only causes subtle defects in the maturation of autolysosomes. The strong phenotype of the Wdr45l mutant is strikingly similar to that observed in Dictyostelium cells lacking Vmp1, an ER protein required for omegasome formation. Common phenotypes include impaired growth in axenic medium, lack of aggregation, and local enrichment of PtdIns3P as determined by the use of lipid reporters. In addition, Vmp1 and Wdr45l mutants show a chronically active response to ER stress. For both mutants, this altered PtdIns3P localization can be prevented by the additional mutation of the upstream regulator Atg1, which also leads to recovery of axenic growth and reduction of ER stress. We propose that, in addition to an autophagy defect, local autophagy-associated PtdIns3P accumulation might contribute to the pathogenesis of BPAN by disrupting ER homeostasis. The introduction of BPAN-associated mutations in Dictyostelium Wdr45l reveals the impact of pathogenic residues on the function and localization of the protein.
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Affiliation(s)
- Alba Tornero-Écija
- C.S.I.C./U.A.M., Instituto De Investigaciones Biomédicas Alberto Sols, Madrid, Spain
| | - Luis-Carlos Tábara
- C.S.I.C./U.A.M., Instituto De Investigaciones Biomédicas Alberto Sols, Madrid, Spain
| | - Miranda Bueno-Arribas
- C.S.I.C./U.A.M., Instituto De Investigaciones Biomédicas Alberto Sols, Madrid, Spain
| | - Laura Antón-Esteban
- C.S.I.C./U.A.M., Instituto De Investigaciones Biomédicas Alberto Sols, Madrid, Spain
| | | | - Irene Sánchez
- C.S.I.C./U.A.M., Instituto De Investigaciones Biomédicas Alberto Sols, Madrid, Spain
| | - Olivier Vincent
- C.S.I.C./U.A.M., Instituto De Investigaciones Biomédicas Alberto Sols, Madrid, Spain
| | - Ricardo Escalante
- C.S.I.C./U.A.M., Instituto De Investigaciones Biomédicas Alberto Sols, Madrid, Spain
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Gomez RE, Lupette J, Chambaud C, Castets J, Ducloy A, Cacas JL, Masclaux-Daubresse C, Bernard A. How Lipids Contribute to Autophagosome Biogenesis, a Critical Process in Plant Responses to Stresses. Cells 2021; 10:1272. [PMID: 34063958 PMCID: PMC8224036 DOI: 10.3390/cells10061272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/03/2021] [Accepted: 05/17/2021] [Indexed: 01/18/2023] Open
Abstract
Throughout their life cycle, plants face a tremendous number of environmental and developmental stresses. To respond to these different constraints, they have developed a set of refined intracellular systems including autophagy. This pathway, highly conserved among eukaryotes, is induced by a wide range of biotic and abiotic stresses upon which it mediates the degradation and recycling of cytoplasmic material. Central to autophagy is the formation of highly specialized double membrane vesicles called autophagosomes which select, engulf, and traffic cargo to the lytic vacuole for degradation. The biogenesis of these structures requires a series of membrane remodeling events during which both the quantity and quality of lipids are critical to sustain autophagy activity. This review highlights our knowledge, and raises current questions, regarding the mechanism of autophagy, and its induction and regulation upon environmental stresses with a particular focus on the fundamental contribution of lipids. How autophagy regulates metabolism and the recycling of resources, including lipids, to promote plant acclimation and resistance to stresses is further discussed.
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Affiliation(s)
- Rodrigo Enrique Gomez
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Josselin Lupette
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Clément Chambaud
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Julie Castets
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Amélie Ducloy
- Institut Jean-Pierre Bourgin, UMR 1318 AgroParisTech-INRAE, Université Paris-Saclay, 78000 Versailles, France; (A.D.); (J.-L.C.); (C.M.-D.)
| | - Jean-Luc Cacas
- Institut Jean-Pierre Bourgin, UMR 1318 AgroParisTech-INRAE, Université Paris-Saclay, 78000 Versailles, France; (A.D.); (J.-L.C.); (C.M.-D.)
| | - Céline Masclaux-Daubresse
- Institut Jean-Pierre Bourgin, UMR 1318 AgroParisTech-INRAE, Université Paris-Saclay, 78000 Versailles, France; (A.D.); (J.-L.C.); (C.M.-D.)
| | - Amélie Bernard
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
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A model for a partnership of lipid transfer proteins and scramblases in membrane expansion and organelle biogenesis. Proc Natl Acad Sci U S A 2021; 118:2101562118. [PMID: 33850023 PMCID: PMC8072408 DOI: 10.1073/pnas.2101562118] [Citation(s) in RCA: 129] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The autophagy protein ATG2, proposed to transfer bulk lipid from the endoplasmic reticulum (ER) during autophagosome biogenesis, interacts with ER residents TMEM41B and VMP1 and with ATG9, in Golgi-derived vesicles that initiate autophagosome formation. In vitro assays reveal TMEM41B, VMP1, and ATG9 as scramblases. We propose a model wherein membrane expansion results from the partnership of a lipid transfer protein, moving lipids between the cytosolic leaflets of apposed organelles, and scramblases that reequilibrate the leaflets of donor and acceptor organelle membranes as lipids are depleted or augmented. TMEM41B and VMP1 are implicated broadly in lipid homeostasis and membrane dynamics processes in which their scrambling activities likely are key.
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Melia TJ, Lystad AH, Simonsen A. Autophagosome biogenesis: From membrane growth to closure. J Cell Biol 2021; 219:151729. [PMID: 32357219 PMCID: PMC7265318 DOI: 10.1083/jcb.202002085] [Citation(s) in RCA: 164] [Impact Index Per Article: 54.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/04/2020] [Accepted: 04/06/2020] [Indexed: 12/14/2022] Open
Abstract
Autophagosome biogenesis involves de novo formation of a membrane that elongates to sequester cytoplasmic cargo and closes to form a double-membrane vesicle (an autophagosome). This process has remained enigmatic since its initial discovery >50 yr ago, but our understanding of the mechanisms involved in autophagosome biogenesis has increased substantially during the last 20 yr. Several key questions do remain open, however, including, What determines the site of autophagosome nucleation? What is the origin and lipid composition of the autophagosome membrane? How is cargo sequestration regulated under nonselective and selective types of autophagy? This review provides key insight into the core molecular mechanisms underlying autophagosome biogenesis, with a specific emphasis on membrane modeling events, and highlights recent conceptual advances in the field.
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Affiliation(s)
- Thomas J Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Alf H Lystad
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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Xu C, Fan J, Shanklin J. Metabolic and functional connections between cytoplasmic and chloroplast triacylglycerol storage. Prog Lipid Res 2020; 80:101069. [DOI: 10.1016/j.plipres.2020.101069] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/23/2020] [Accepted: 10/24/2020] [Indexed: 12/14/2022]
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Yamamoto YH, Noda T. Autophagosome formation in relation to the endoplasmic reticulum. J Biomed Sci 2020; 27:97. [PMID: 33087127 PMCID: PMC7579975 DOI: 10.1186/s12929-020-00691-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/02/2020] [Indexed: 02/08/2023] Open
Abstract
Autophagy is a process in which a myriad membrane structures called autophagosomes are formed de novo in a single cell, which deliver the engulfed substrates into lysosomes for degradation. The size of the autophagosomes is relatively uniform in non-selective autophagy and variable in selective autophagy. It has been recently established that autophagosome formation occurs near the endoplasmic reticulum (ER). In this review, we have discussed recent advances in the relationship between autophagosome formation and endoplasmic reticulum. Autophagosome formation occurs near the ER subdomain enriched with phospholipid synthesizing enzymes like phosphatidylinositol synthase (PIS)/CDP-diacylglycerol-inositol 3-phosphatidyltransferase (CDIPT) and choline/ethanolamine phosphotransferase 1 (CEPT1). Autophagy-related protein 2 (Atg2), which is involved in autophagosome formation has a lipid transfer capacity and is proposed to directly transfer the lipid molecules from the ER to form autophagosomes. Vacuole membrane protein 1 (VMP1) and transmembrane protein 41b (TMEM41b) are ER membrane proteins that are associated with the formation of the subdomain. Recently, we have reported that an uncharacterized ER membrane protein possessing the DNAJ domain, called ERdj8/DNAJC16, is associated with the regulation of the size of autophagosomes. The localization of ERdj8/DNAJC16 partially overlaps with the PIS-enriched ER subdomain, thereby implying its association with autophagosome size determination.
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Affiliation(s)
- Yo-Hei Yamamoto
- Center for Frontier Oral Sciences, Graduate School of Dentistry, Osaka University Graduate School, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takeshi Noda
- Center for Frontier Oral Sciences, Graduate School of Dentistry, Osaka University Graduate School, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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Emerging roles of ATG proteins and membrane lipids in autophagosome formation. Cell Discov 2020; 6:32. [PMID: 32509328 PMCID: PMC7248066 DOI: 10.1038/s41421-020-0161-3] [Citation(s) in RCA: 149] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/21/2020] [Indexed: 12/12/2022] Open
Abstract
Autophagosome biogenesis is a dynamic membrane event, which is executed by the sequential function of autophagy-related (ATG) proteins. Upon autophagy induction, a cup-shaped membrane structure appears in the cytoplasm, then elongates sequestering cytoplasmic materials, and finally forms a closed double membrane autophagosome. However, how this complex vesicle formation event is strictly controlled and achieved is still enigmatic. Recently, there is accumulating evidence showing that some ATG proteins have the ability to directly interact with membranes, transfer lipids between membranes and regulate lipid metabolism. A novel role for various membrane lipids in autophagosome formation is also emerging. Here, we highlight past and recent key findings on the function of ATG proteins related to autophagosome biogenesis and consider how ATG proteins control this dynamic membrane formation event to organize the autophagosome by collaborating with membrane lipids.
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How is the acyl chain composition of phosphoinositides created and does it matter? Biochem Soc Trans 2020; 47:1291-1305. [PMID: 31657437 PMCID: PMC6824679 DOI: 10.1042/bst20190205] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/27/2019] [Accepted: 10/01/2019] [Indexed: 12/11/2022]
Abstract
The phosphoinositide (PIPn) family of signalling phospholipids are central regulators in membrane cell biology. Their varied functions are based on the phosphorylation pattern of their inositol ring, which can be recognized by selective binding domains in their effector proteins and be modified by a series of specific PIPn kinases and phosphatases, which control their interconversion in a spatial and temporal manner. Yet, a unique feature of PIPns remains largely unexplored: their unusually uniform acyl chain composition. Indeed, while most phospholipids present a range of molecular species comprising acyl chains of diverse length and saturation, PIPns in several organisms and tissues show the predominance of a single hydrophobic backbone, which in mammals is composed of arachidonoyl and stearoyl chains. Despite evolution having favoured this specific PIPn configuration, little is known regarding the mechanisms and functions behind it. In this review, we explore the metabolic pathways that could control the acyl chain composition of PIPns as well as the potential roles of this selective enrichment. While our understanding of this phenomenon has been constrained largely by the technical limitations in the methods traditionally employed in the PIPn field, we believe that the latest developments in PIPn analysis should shed light onto this old question.
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Morishita H, Zhao YG, Tamura N, Nishimura T, Kanda Y, Sakamaki Y, Okazaki M, Li D, Mizushima N. A critical role of VMP1 in lipoprotein secretion. eLife 2019; 8:48834. [PMID: 31526472 PMCID: PMC6748824 DOI: 10.7554/elife.48834] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/23/2019] [Indexed: 12/12/2022] Open
Abstract
Lipoproteins are lipid-protein complexes that are primarily generated and secreted from the intestine, liver, and visceral endoderm and delivered to peripheral tissues. Lipoproteins, which are assembled in the endoplasmic reticulum (ER) membrane, are released into the ER lumen for secretion, but its mechanism remains largely unknown. Here, we show that the release of lipoproteins from the ER membrane requires VMP1, an ER transmembrane protein essential for autophagy and certain types of secretion. Loss of vmp1, but not other autophagy-related genes, in zebrafish causes lipoprotein accumulation in the intestine and liver. Vmp1 deficiency in mice also leads to lipid accumulation in the visceral endoderm and intestine. In VMP1-depleted cells, neutral lipids accumulate within lipid bilayers of the ER membrane, thus affecting lipoprotein secretion. These results suggest that VMP1 is important for the release of lipoproteins from the ER membrane to the ER lumen in addition to its previously known functions.
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Affiliation(s)
- Hideaki Morishita
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Yan G Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States
| | - Norito Tamura
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Taki Nishimura
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Yuki Kanda
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Yuriko Sakamaki
- Microscopy Research Support Unit Research Core, Tokyo Medical and Dental University, Tokyo, Japan
| | | | - Dongfang Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan
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Amirfallah A, Arason A, Einarsson H, Gudmundsdottir ET, Freysteinsdottir ES, Olafsdottir KA, Johannsson OT, Agnarsson BA, Barkardottir RB, Reynisdottir I. High expression of the vacuole membrane protein 1 (VMP1) is a potential marker of poor prognosis in HER2 positive breast cancer. PLoS One 2019; 14:e0221413. [PMID: 31442252 PMCID: PMC6707546 DOI: 10.1371/journal.pone.0221413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/06/2019] [Indexed: 02/07/2023] Open
Abstract
Background Fusion genes result from genomic structural changes, which can lead to alterations in gene expression that supports tumor development. The aim of the study was to use fusion genes as a tool to identify new breast cancer (BC) genes with a role in BC progression. Methods Fusion genes from breast tumors and BC cell lines were collected from publications. RNA-Seq data from tumors and cell lines were retrieved from databanks and analyzed for fusions with SOAPfuse or the analysis was purchased. Fusion genes identified in both tumors (n = 1724) and cell lines (n = 45) were confirmed by qRT-PCR and sequencing. Their individual genes were ranked by selection criteria that included correlation of their mRNA level with copy number. The expression of the top ranked gene was measured by qRT-PCR in normal tissue and in breast tumors from an exploratory cohort (n = 141) and a validation cohort (n = 277). Expression levels were correlated with clinical and pathological factors as well as the patients’ survival. The results were followed up in BC cohorts from TCGA (n = 818) and METABRIC (n = 2509). Results Vacuole membrane protein 1 (VMP1) was the most promising candidate based on specific selection criteria. Its expression was higher in breast tumor tissue than normal tissue (p = 1x10-4), and its expression was significantly higher in HER2 positive than HER2 negative breast tumors in all four cohorts analyzed. High expression of VMP1 associated with breast cancer specific survival (BCSS) in cohort 1 (hazard ratio (HR) = 2.31, CI 1.27–4.18) and METABRIC (HR = 1.26, CI 1.02–1.57), and also after adjusting for HER2 expression in cohort 1 (HR = 2.03, CI 1.10–3.72). BCSS was not significant in cohort 2 or TCGA cohort, which may be due to differences in treatment regimens. Conclusions The results suggest that high VMP1 expression is a potential marker of poor prognosis in HER2 positive BC. Further studies are needed to elucidate how VMP1 could affect pathways supportive of tumorigenesis.
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Affiliation(s)
- Arsalan Amirfallah
- Cell Biology Unit at the Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
- The Biomedical Center, University of Iceland, Reykjavik, Iceland
| | - Adalgeir Arason
- The Biomedical Center, University of Iceland, Reykjavik, Iceland
- Molecular Pathology Unit at the Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
| | - Hjorleifur Einarsson
- Cell Biology Unit at the Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
| | - Eydis Thorunn Gudmundsdottir
- Cell Biology Unit at the Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
| | - Edda Sigridur Freysteinsdottir
- Molecular Pathology Unit at the Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
| | | | - Oskar Thor Johannsson
- Department of Oncology, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
| | - Bjarni Agnar Agnarsson
- Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Rosa Bjork Barkardottir
- The Biomedical Center, University of Iceland, Reykjavik, Iceland
- Molecular Pathology Unit at the Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
| | - Inga Reynisdottir
- Cell Biology Unit at the Pathology Department, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
- The Biomedical Center, University of Iceland, Reykjavik, Iceland
- * E-mail:
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Blunsom NJ, Cockcroft S. Phosphatidylinositol synthesis at the endoplasmic reticulum. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158471. [PMID: 31173893 DOI: 10.1016/j.bbalip.2019.05.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/21/2019] [Accepted: 05/23/2019] [Indexed: 12/23/2022]
Abstract
Phosphatidylinositol (PI) is a minor phospholipid with a characteristic fatty acid profile; it is highly enriched in stearic acid at the sn-1 position and arachidonic acid at the sn-2 position. PI is phosphorylated into seven specific derivatives, and individual species are involved in a vast array of cellular functions including signalling, membrane traffic, ion channel regulation and actin dynamics. De novo PI synthesis takes place at the endoplasmic reticulum where phosphatidic acid (PA) is converted to PI in two enzymatic steps. PA is also produced at the plasma membrane during phospholipase C signalling, where hydrolysis of phosphatidylinositol (4,5) bisphosphate (PI(4,5)P2) leads to the production of diacylglycerol which is rapidly phosphorylated to PA. This PA is transferred to the ER to be also recycled back to PI. For the synthesis of PI, CDP-diacylglycerol synthase (CDS) converts PA to the intermediate, CDP-DG, which is then used by PI synthase to make PI. The de novo synthesised PI undergoes remodelling to acquire its characteristic fatty acid profile, which is altered in p53-mutated cancer cells. In mammals, there are two CDS enzymes at the ER, CDS1 and CDS2. In this review, we summarise the de novo synthesis of PI at the ER and the enzymes involved in its subsequent remodelling to acquire its characteristic acyl chains. We discuss how CDS, the rate limiting enzymes in PI synthesis are regulated by different mechanisms. During phospholipase C signalling, the CDS1 enzyme is specifically upregulated by cFos via protein kinase C.
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Affiliation(s)
- Nicholas J Blunsom
- Dept. of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London WC1E 6JJ, UK
| | - Shamshad Cockcroft
- Dept. of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London WC1E 6JJ, UK.
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