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Isola D, Elazar Z. Phospholipid Supply for Autophagosome Biogenesis. J Mol Biol 2024:168691. [PMID: 38944336 DOI: 10.1016/j.jmb.2024.168691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 06/10/2024] [Accepted: 06/24/2024] [Indexed: 07/01/2024]
Abstract
Autophagy is a cellular degradation pathway where double-membrane autophagosomes form de novo to engulf cytoplasmic material destined for lysosomal degradation. This process requires regulated membrane remodeling, beginning with the initial autophagosomal precursor and progressing to its elongation and maturation into a fully enclosed, fusion-capable vesicle. While the core protein machinery involved in autophagosome formation has been extensively studied over the past two decades, the role of phospholipids in this process has only recently been studied. This review focuses on the phospholipid composition of the phagophore membrane and the mechanisms that supply lipids to expand this unique organelle.
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Affiliation(s)
- Damilola Isola
- Departments of Biomolecular Sciences, The Weizmann Institute of Science 76100 Rehovot, Israel
| | - Zvulun Elazar
- Departments of Biomolecular Sciences, The Weizmann Institute of Science 76100 Rehovot, Israel.
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2
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Nähse V, Stenmark H, Schink KO. Omegasomes control formation, expansion, and closure of autophagosomes. Bioessays 2024; 46:e2400038. [PMID: 38724256 DOI: 10.1002/bies.202400038] [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: 02/15/2024] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 05/28/2024]
Abstract
Autophagy, an essential cellular process for maintaining cellular homeostasis and eliminating harmful cytoplasmic objects, involves the de novo formation of double-membraned autophagosomes that engulf and degrade cellular debris, protein aggregates, damaged organelles, and pathogens. Central to this process is the phagophore, which forms from donor membranes rich in lipids synthesized at various cellular sites, including the endoplasmic reticulum (ER), which has emerged as a primary source. The ER-associated omegasomes, characterized by their distinctive omega-shaped structure and accumulation of phosphatidylinositol 3-phosphate (PI3P), play a pivotal role in autophagosome formation. Omegasomes are thought to serve as platforms for phagophore assembly by recruiting essential proteins such as DFCP1/ZFYVE1 and facilitating lipid transfer to expand the phagophore. Despite the critical importance of phagophore biogenesis, many aspects remain poorly understood, particularly the complete range of proteins involved in omegasome dynamics, and the detailed mechanisms of lipid transfer and membrane contact site formation.
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Affiliation(s)
- Viola Nähse
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Kay O Schink
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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3
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Muramoto M, Mineoka N, Fukuda K, Kuriyama S, Masatani T, Fujita A. Coordinated regulation of phosphatidylinositol 4-phosphate and phosphatidylserine levels by Osh4p and Osh5p is an essential regulatory mechanism in autophagy. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184308. [PMID: 38437942 DOI: 10.1016/j.bbamem.2024.184308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 01/26/2024] [Accepted: 02/26/2024] [Indexed: 03/06/2024]
Abstract
Macroautophagy (hereafter autophagy) is an intracellular degradative pathway in budding yeast cells. Certain lipid types play essential roles in autophagy; yet the precise mechanisms regulating lipid composition during autophagy remain unknown. Here, we explored the role of the Osh family proteins in the modulating lipid composition during autophagy in budding yeast. Our results showed that osh1-osh7∆ deletions lead to autophagic dysfunction, with impaired GFP-Atg8 processing and the absence of autophagosomes and autophagic bodies in the cytosol and vacuole, respectively. Freeze-fracture electron microscopy (EM) revealed elevated phosphatidylinositol 4-phosphate (PtdIns(4)P) levels in cytoplasmic and luminal leaflets of autophagic bodies and vacuolar membranes in all deletion mutants. Phosphatidylserine (PtdSer) levels were significantly decreased in the autophagic bodies and vacuolar membranes in osh4∆ and osh5∆ mutants, whereas no significant changes were observed in other osh deletion mutants. Furthermore, we identified defects in autophagic processes in the osh4∆ and osh5∆ mutants, including rare autophagosome formation in the osh5∆ mutant and accumulation of autophagic bodies in the vacuole in the osh4∆ mutant, even in the absence of the proteinase inhibitor PMSF. These findings suggest that Osh4p and Osh5p play crucial roles in the transport of PtdSer to autophagic bodies and autophagosome membranes, respectively. The precise control of lipid composition in the membranes of autophagosomes and autophagic bodies by Osh4p and Osh5p represents an important regulatory mechanism in autophagy.
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Affiliation(s)
- Moe Muramoto
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Nanaru Mineoka
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Kayoko Fukuda
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Sayuri Kuriyama
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Tatsunori Masatani
- Laboratory of Zoonotic Diseases, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Center for One Medicine Innovative Translational Research (COMIT), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Akikazu Fujita
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan.
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Ren Q, Sun Q, Fu J. Dysfunction of autophagy in high-fat diet-induced non-alcoholic fatty liver disease. Autophagy 2024; 20:221-241. [PMID: 37700498 PMCID: PMC10813589 DOI: 10.1080/15548627.2023.2254191] [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: 05/01/2023] [Accepted: 08/24/2023] [Indexed: 09/14/2023] Open
Abstract
ABBREVIATIONS ACOX1: acyl-CoA oxidase 1; ADH5: alcohol dehydrogenase 5 (class III), chi polypeptide; ADIPOQ: adiponectin, C1Q and collagen domain containing; ATG: autophagy related; BECN1: beclin 1; CRTC2: CREB regulated transcription coactivator 2; ER: endoplasmic reticulum; F2RL1: F2R like trypsin receptor 1; FA: fatty acid; FOXO1: forkhead box O1; GLP1R: glucagon like peptide 1 receptor; GRK2: G protein-coupled receptor kinase 2; GTPase: guanosine triphosphatase; HFD: high-fat diet; HSCs: hepatic stellate cells; HTRA2: HtrA serine peptidase 2; IRGM: immunity related GTPase M; KD: knockdown; KDM6B: lysine demethylase 6B; KO: knockout; LAMP2: lysosomal associated membrane protein 2; LAP: LC3-associated phagocytosis; LDs: lipid droplets; Li KO: liver-specific knockout; LSECs: liver sinusoidal endothelial cells; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAP3K5: mitogen-activated protein kinase kinase kinase 5; MED1: mediator complex subunit 1; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin complex 1; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; NFE2L2: NFE2 like bZIP transcription factor 2; NOS3: nitric oxide synthase 3; NR1H3: nuclear receptor subfamily 1 group H member 3; OA: oleic acid; OE: overexpression; OSBPL8: oxysterol binding protein like 8; PA: palmitic acid; RUBCNL: rubicon like autophagy enhancer; PLIN2: perilipin 2; PLIN3: perilipin 3; PPARA: peroxisome proliferator activated receptor alpha; PRKAA2/AMPK: protein kinase AMP-activated catalytic subunit alpha 2; RAB: member RAS oncogene family; RPTOR: regulatory associated protein of MTOR complex 1; SCD: stearoyl-CoA desaturase; SIRT1: sirtuin 1; SIRT3: sirtuin 3; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SQSTM1/p62: sequestosome 1; SREBF1: sterol regulatory element binding transcription factor 1;SREBF2: sterol regulatory element binding transcription factor 2; STING1: stimulator of interferon response cGAMP interactor 1; STX17: syntaxin 17; TAGs: triacylglycerols; TFEB: transcription factor EB; TP53/p53: tumor protein p53; ULK1: unc-51 like autophagy activating kinase 1; VMP1: vacuole membrane protein 1.
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Affiliation(s)
- Qiannan Ren
- Department of Endocrinology, Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Qiming Sun
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, Zhejiang, China
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Junfen Fu
- Department of Endocrinology, Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
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Peters B, Dattner T, Schlieben LD, Sun T, Staufner C, Lenz D. Disorders of vesicular trafficking presenting with recurrent acute liver failure: NBAS, RINT1, and SCYL1 deficiency. J Inherit Metab Dis 2024. [PMID: 38279772 DOI: 10.1002/jimd.12707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 01/28/2024]
Abstract
Among genetic disorders of vesicular trafficking, there are three causing recurrent acute liver failure (RALF): NBAS, RINT1, and SCYL1-associated disease. These three disorders are characterized by liver crises triggered by febrile infections and account for a relevant proportion of RALF causes. While the frequency and severity of liver crises in NBAS and RINT1-associated disease decrease with age, patients with SCYL1 variants present with a progressive, cholestatic course. In all three diseases, there is a multisystemic, partially overlapping phenotype with variable expression, including liver, skeletal, and nervous systems, all organ systems with high secretory activity. There are no specific biomarkers for these diseases, and whole exome sequencing should be performed in patients with RALF of unknown etiology. NBAS, SCYL1, and RINT1 are involved in antegrade and retrograde vesicular trafficking. Pathomechanisms remain unclarified, but there is evidence of a decrease in concentration and stability of the protein primarily affected by the respective gene defect and its interaction partners, potentially causing impairment of vesicular transport. The impairment of protein secretion by compromised antegrade transport provides a possible explanation for different organ manifestations such as bone alteration due to lack of collagens or diabetes mellitus when insulin secretion is affected. Dysfunction of retrograde transport impairs membrane recycling and autophagy. The impairment of vesicular trafficking results in increased endoplasmic reticulum stress, which, in hepatocytes, can progress to hepatocytolysis. While there is no curative therapy, an early and consequent implementation of an emergency protocol seems crucial for optimal therapeutic management.
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Affiliation(s)
- Bianca Peters
- Medical Faculty Heidelberg, Center for Paediatric and Adolescent Medicine, Department I, Division of Paediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Tal Dattner
- Medical Faculty Heidelberg, Center for Paediatric and Adolescent Medicine, Department I, Division of Paediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Lea D Schlieben
- School of Medicine, Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Institute of Neurogenomics, Computational Health Centre, Helmholtz Zentrum München, Neuherberg, Germany
| | - Tian Sun
- Medical Faculty Heidelberg, Center for Paediatric and Adolescent Medicine, Department I, Division of Paediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Christian Staufner
- Medical Faculty Heidelberg, Center for Paediatric and Adolescent Medicine, Department I, Division of Paediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Dominic Lenz
- Medical Faculty Heidelberg, Center for Paediatric and Adolescent Medicine, Department I, Division of Paediatric Neurology and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
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Babazadeh R, Schneider KL, Fischbach A, Hao X, Liu B, Nystrom T. The yeast guanine nucleotide exchange factor Sec7 is a bottleneck in spatial protein quality control and detoxifies neurological disease proteins. Sci Rep 2023; 13:14068. [PMID: 37640758 PMCID: PMC10462735 DOI: 10.1038/s41598-023-41188-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023] Open
Abstract
ER-to-Golgi trafficking partakes in the sorting of misfolded cytoplasmic proteins to reduce their cytological toxicity. We show here that yeast Sec7, a protein involved in proliferation of the Golgi, is part of this pathway and participates in an Hsp70-dependent formation of insoluble protein deposits (IPOD). Sec7 associates with the disaggregase Hsp104 during a mild heat shock and increases the rate of Hsp104 diffusion in an Hsp70-dependent manner when overproduced. Sec7 overproduction increased formation of IPODs from smaller aggregates and mitigated the toxicity of Huntingtin exon-1 upon heat stress while Sec7 depletion increased sensitivity to aẞ42 of the Alzheimer's disease and α-synuclein of the Parkinson's disease, suggesting a role of Sec7 in mitigating proteotoxicity.
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Affiliation(s)
- Roja Babazadeh
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Kara L Schneider
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Arthur Fischbach
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Xinxin Hao
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Beidong Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9 C, 413 90, Gothenburg, Sweden
| | - Thomas Nystrom
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, 405 30, Gothenburg, Sweden.
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Pathogenic Aspects and Therapeutic Avenues of Autophagy in Parkinson's Disease. Cells 2023; 12:cells12040621. [PMID: 36831288 PMCID: PMC9954720 DOI: 10.3390/cells12040621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/07/2023] [Accepted: 02/11/2023] [Indexed: 02/17/2023] Open
Abstract
The progressive aging of the population and the fact that Parkinson's disease currently does not have any curative treatment turn out to be essential issues in the following years, where research has to play a critical role in developing therapy. Understanding this neurodegenerative disorder keeps advancing, proving the discovery of new pathogenesis-related genes through genome-wide association analysis. Furthermore, the understanding of its close link with the disruption of autophagy mechanisms in the last few years permits the elaboration of new animal models mimicking, through multiple pathways, different aspects of autophagic dysregulation, with the presence of pathological hallmarks, in brain regions affected by Parkinson's disease. The synergic advances in these fields permit the elaboration of multiple therapeutic strategies for restoring autophagy activity. This review discusses the features of Parkinson's disease, the autophagy mechanisms and their involvement in pathogenesis, and the current methods to correct this cellular pathway, from the development of animal models to the potentially curative treatments in the preclinical and clinical phase studies, which are the hope for patients who do not currently have any curative treatment.
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Kriegenburg F, Huiting W, van Buuren-Broek F, Zwilling E, Hardenberg R, Mari M, Kraft C, Reggiori F. The lipid flippase Drs2 regulates anterograde transport of Atg9 during autophagy. AUTOPHAGY REPORTS 2022; 1:345-367. [PMID: 38106996 PMCID: PMC7615381 DOI: 10.1080/27694127.2022.2104781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Macroautophagy/autophagy is a conserved catabolic pathway during which cellular material is sequestered within newly formed double-membrane vesicles called autophagosomes and delivered to the lytic compartment of eukaryotic cells for degradation. Autophagosome biogenesis depends on the core autophagy-related (Atg) machinery, and involves a massive supply and remodelling of membranes. To gain insight into the lipid remodelling mechanisms during autophagy, we have systematically investigated whether lipid flippases are required for this pathway in the yeast Saccharomyces cerevisiae. We found that the flippase Drs2, which transfers phosphatidylserine and phosphatidylethanolamine from the lumenal to the cytosolic leaflet of the limiting membrane at the trans-Golgi network, is required for normal progression of autophagy. We also show that Drs2 is important for the trafficking of the core Atg protein Atg9. Atg9 is a transmembrane protein important for autophagosome biogenesis and its anterograde transport from its post-Golgi reservoirs to the site of autophagosome formation is severely impaired in the absence of Drs2. Thus, our results identify a novel autophagy player and highlight that membrane asymmetry regulates early autophagy steps.
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Affiliation(s)
- Franziska Kriegenburg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University medical Centre Groningen, 9713AV Groningen, The Netherlands
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Wouter Huiting
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University medical Centre Groningen, 9713AV Groningen, The Netherlands
| | - Fleur van Buuren-Broek
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University medical Centre Groningen, 9713AV Groningen, The Netherlands
| | - Emma Zwilling
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University medical Centre Groningen, 9713AV Groningen, The Netherlands
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark
| | - Ralph Hardenberg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University medical Centre Groningen, 9713AV Groningen, The Netherlands
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University medical Centre Groningen, 9713AV Groningen, The Netherlands
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University medical Centre Groningen, 9713AV Groningen, The Netherlands
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark
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Mailler E, Guardia CM, Bai X, Jarnik M, Williamson CD, Li Y, Maio N, Golden A, Bonifacino JS. The autophagy protein ATG9A enables lipid mobilization from lipid droplets. Nat Commun 2021; 12:6750. [PMID: 34799570 PMCID: PMC8605025 DOI: 10.1038/s41467-021-26999-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 10/26/2021] [Indexed: 01/18/2023] Open
Abstract
The multispanning membrane protein ATG9A is a scramblase that flips phospholipids between the two membrane leaflets, thus contributing to the expansion of the phagophore membrane in the early stages of autophagy. Herein, we show that depletion of ATG9A does not only inhibit autophagy but also increases the size and/or number of lipid droplets in human cell lines and C. elegans. Moreover, ATG9A depletion blocks transfer of fatty acids from lipid droplets to mitochondria and, consequently, utilization of fatty acids in mitochondrial respiration. ATG9A localizes to vesicular-tubular clusters (VTCs) that are tightly associated with an ER subdomain enriched in another multispanning membrane scramblase, TMEM41B, and also in close proximity to phagophores, lipid droplets and mitochondria. These findings indicate that ATG9A plays a critical role in lipid mobilization from lipid droplets to autophagosomes and mitochondria, highlighting the importance of ATG9A in both autophagic and non-autophagic processes.
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Affiliation(s)
- Elodie Mailler
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Carlos M Guardia
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Xiaofei Bai
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michal Jarnik
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Chad D Williamson
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Yan Li
- Proteomics Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Nunziata Maio
- Metals Biology and Molecular Medicine Group, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Andy Golden
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Juan S Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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10
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Involvement of Autophagy in Ageing and Chronic Cholestatic Diseases. Cells 2021; 10:cells10102772. [PMID: 34685751 PMCID: PMC8534511 DOI: 10.3390/cells10102772] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/05/2021] [Accepted: 10/13/2021] [Indexed: 01/18/2023] Open
Abstract
Autophagy is a “housekeeping” lysosomal degradation process involved in numerous physiological and pathological processes in all eukaryotic cells. The dysregulation of hepatic autophagy has been described in several conditions, from obesity to diabetes and cholestatic disease. We review the role of autophagy, focusing on age-related cholestatic diseases, and discuss its therapeutic potential and the molecular targets identified to date. The accumulation of toxic BAs is the main cause of cell damage in cholestasis patients. BAs and their receptor, FXR, have been implicated in the regulation of hepatic autophagy. The mechanisms by which cholestasis induces liver damage include mitochondrial dysfunction, oxidative stress and ER stress, which lead to cell death and ultimately to liver fibrosis as a compensatory mechanism to reduce the damage. The stimulation of autophagy seems to ameliorate the liver damage. Autophagic activity decreases with age in several species, whereas its basic extends lifespan in animals, suggesting that it is one of the convergent mechanisms of several longevity pathways. No strategies aimed at inducing autophagy have yet been tested in cholestasis patients. However, its stimulation can be viewed as a novel therapeutic strategy that may reduce ageing-dependent liver deterioration and also mitigate hepatic steatosis.
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11
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Porin 1 Modulates Autophagy in Yeast. Cells 2021; 10:cells10092416. [PMID: 34572064 PMCID: PMC8464718 DOI: 10.3390/cells10092416] [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] [Received: 08/20/2021] [Revised: 09/07/2021] [Accepted: 09/09/2021] [Indexed: 12/27/2022] Open
Abstract
Autophagy is a cellular recycling program which efficiently reduces the cellular burden of ageing. Autophagy is characterised by nucleation of isolation membranes, which grow in size and further expand to form autophagosomes, engulfing cellular material to be degraded by fusion with lysosomes (vacuole in yeast). Autophagosomal membranes do not bud from a single cell organelle, but are generated de novo. Several lipid sources for autophagosomal membranes have been identified, but the whole process of their generation is complex and not entirely understood. In this study, we investigated how the mitochondrial outer membrane protein porin 1 (Por1), the yeast orthologue of mammalian voltage-dependent anion channel (VDAC), affects autophagy in yeast. We show that POR1 deficiency reduces the autophagic capacity and leads to changes in vacuole and lipid homeostasis. We further investigated whether limited phosphatidylethanolamine (PE) availability in por1∆ was causative for reduced autophagy by overexpression of the PE-generating phosphatidylserine decarboxylase 1 (Psd1). Altogether, our results show that POR1 deficiency is associated with reduced autophagy, which can be circumvented by additional PSD1 overexpression. This suggests a role for Por1 in Psd1-mediated autophagy regulation.
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12
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Zhang X, Deibert CP, Kim WJ, Jaman E, Rao AV, Lotze MT, Amankulor NM. Autophagy inhibition is the next step in the treatment of glioblastoma patients following the Stupp era. Cancer Gene Ther 2021; 28:971-983. [PMID: 32759988 DOI: 10.1038/s41417-020-0205-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/17/2020] [Accepted: 07/22/2020] [Indexed: 01/30/2023]
Abstract
It has now been nearly 15 years since the last major advance in the treatment of patients with glioma. "The addition of temozolomide to radiotherapy for newly diagnosed glioblastoma resulted in a clinically meaningful and statistically significant survival benefit with minimal additional toxicity". Autophagy is primarily a survival pathway, literally self-eating, that is utilized in response to stress (such as radiation and chemotherapy), enabling clearance of effete protein aggregates and multimolecular assemblies. Promising results have been observed in patients with glioma for over a decade now when autophagy inhibition with chloroquine derivatives coupled with conventional therapy. The application of autophagy inhibitors, the role of immune cell-induced autophagy, and the potential role of novel cellular and gene therapies, should now be considered for development as part of this well-established regimen.
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Affiliation(s)
- Xiaoran Zhang
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Christopher P Deibert
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Wi-Jin Kim
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Emade Jaman
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Aparna V Rao
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Michael T Lotze
- Department of Surgery, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
| | - Nduka M Amankulor
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
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13
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Lei Z, Wang J, Zhang L, Liu CH. Ubiquitination-Dependent Regulation of Small GTPases in Membrane Trafficking: From Cell Biology to Human Diseases. Front Cell Dev Biol 2021; 9:688352. [PMID: 34277632 PMCID: PMC8281112 DOI: 10.3389/fcell.2021.688352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/09/2021] [Indexed: 01/04/2023] Open
Abstract
Membrane trafficking is critical for cellular homeostasis, which is mainly carried out by small GTPases, a class of proteins functioning in vesicle budding, transport, tethering and fusion processes. The accurate and organized membrane trafficking relies on the proper regulation of small GTPases, which involves the conversion between GTP- and GDP-bound small GTPases mediated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Emerging evidence indicates that post-translational modifications (PTMs) of small GTPases, especially ubiquitination, play an important role in the spatio-temporal regulation of small GTPases, and the dysregulation of small GTPase ubiquitination can result in multiple human diseases. In this review, we introduce small GTPases-mediated membrane trafficking pathways and the biological processes of ubiquitination-dependent regulation of small GTPases, including the regulation of small GTPase stability, activity and localization. We then discuss the dysregulation of small GTPase ubiquitination and the associated human membrane trafficking-related diseases, focusing on the neurological diseases and infections. An in-depth understanding of the molecular mechanisms by which ubiquitination regulates small GTPases can provide novel insights into the membrane trafficking process, which knowledge is valuable for the development of more effective and specific therapeutics for membrane trafficking-related human diseases.
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Affiliation(s)
- Zehui Lei
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Cui Hua Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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14
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Jiang L, Zheng X, Liu Y, Chen J, Lu Y, Yan F. Plant protein P3IP participates in the regulation of autophagy in Nicotiana benthamiana. PLANT SIGNALING & BEHAVIOR 2021; 16:1861768. [PMID: 33356829 PMCID: PMC7889025 DOI: 10.1080/15592324.2020.1861768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/04/2020] [Accepted: 12/06/2020] [Indexed: 05/19/2023]
Abstract
Autophagy, a bulk degradation system conserved among most eukaryotes, is also involved in responses to viral infection in plant. In our previous study, a new host factor P3IP was identified to interact with RSV (rice stripe virus) p3 and mediate its autophagic degradation to limit the viral infection. Here, we further discovered that P3IP of Nicotiana benthamiana (NbP3IP) participated in regulation of autophagy. Overexpression of NbP3IP induced autophagy and down-regulation of NbP3IP reduced autophagy. Combined the functions of autophagy-mediated plant defense against plant virus and regulation autophagy, we indicate that P3IP participates in the regulation of autophagy.
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Affiliation(s)
- Liangliang Jiang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Xiying Zheng
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jianping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Yuwen Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Fei Yan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
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15
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Leal NS, Martins LM. Mind the Gap: Mitochondria and the Endoplasmic Reticulum in Neurodegenerative Diseases. Biomedicines 2021; 9:biomedicines9020227. [PMID: 33672391 PMCID: PMC7926795 DOI: 10.3390/biomedicines9020227] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/16/2022] Open
Abstract
The way organelles are viewed by cell biologists is quickly changing. For many years, these cellular entities were thought to be unique and singular structures that performed specific roles. However, in recent decades, researchers have discovered that organelles are dynamic and form physical contacts. In addition, organelle interactions modulate several vital biological functions, and the dysregulation of these contacts is involved in cell dysfunction and different pathologies, including neurodegenerative diseases. Mitochondria–ER contact sites (MERCS) are among the most extensively studied and understood juxtapositioned interorganelle structures. In this review, we summarise the major biological and ultrastructural dysfunctions of MERCS in neurodegeneration, with a particular focus on Alzheimer’s disease as well as Parkinson’s disease, amyotrophic lateral sclerosis and frontotemporal dementia. We also propose an updated version of the MERCS hypothesis in Alzheimer’s disease based on new findings. Finally, we discuss the possibility of MERCS being used as possible drug targets to halt cell death and neurodegeneration.
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16
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Xu F, Tautenhahn HM, Dirsch O, Dahmen U. Modulation of Autophagy: A Novel "Rejuvenation" Strategy for the Aging Liver. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6611126. [PMID: 33628363 PMCID: PMC7889356 DOI: 10.1155/2021/6611126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/08/2020] [Accepted: 01/23/2021] [Indexed: 12/11/2022]
Abstract
Aging is a natural life process which leads to a gradual decline of essential physiological processes. For the liver, it leads to alterations in histomorphology (steatosis and fibrosis) and function (protein synthesis and energy generation) and affects central hepatocellular processes (autophagy, mitochondrial respiration, and hepatocyte proliferation). These alterations do not only impair the metabolic capacity of the liver but also represent important factors in the pathogenesis of malignant liver disease. Autophagy is a recycling process for eukaryotic cells to degrade dysfunctional intracellular components and to reuse the basic substances. It plays a crucial role in maintaining cell homeostasis and in resisting environmental stress. Emerging evidence shows that modulating autophagy seems to be effective in improving the age-related alterations of the liver. However, autophagy is a double-edged sword for the aged liver. Upregulating autophagy alleviates hepatic steatosis and ROS-induced cellular stress and promotes hepatocyte proliferation but may aggravate hepatic fibrosis. Therefore, a well-balanced autophagy modulation strategy might be suitable to alleviate age-related liver dysfunction. Conclusion. Modulation of autophagy is a promising strategy for "rejuvenation" of the aged liver. Detailed knowledge regarding the most devastating processes in the individual patient is needed to effectively counteract aging of the liver without causing obvious harm.
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Affiliation(s)
- Fengming Xu
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena 07747, Germany
| | - Hans-Michael Tautenhahn
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena 07747, Germany
| | - Olaf Dirsch
- Institute of Pathology, Klinikum Chemnitz gGmbH, Chemnitz 09111, Germany
| | - Uta Dahmen
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena 07747, Germany
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17
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Sumiyoshi M, Kotani Y, Ikuta Y, Suzue K, Ozawa M, Katakai T, Yamada T, Abe T, Bando K, Koyasu S, Kanaho Y, Watanabe T, Matsuda S. Arf1 and Arf6 Synergistically Maintain Survival of T Cells during Activation. THE JOURNAL OF IMMUNOLOGY 2020; 206:366-375. [PMID: 33310872 DOI: 10.4049/jimmunol.2000971] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/12/2020] [Indexed: 12/25/2022]
Abstract
ADP-ribosylation factor (Arf) family consisting of six family members, Arf1-Arf6, belongs to Ras superfamily and orchestrates vesicle trafficking under the control of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins. It is well established that brefeldin A, a potent inhibitor of ArfGEFs, blocks cytokine secretion from activated T cells, suggesting that the Arf pathway plays important roles in T cell functions. In this study, because Arf1 and Arf6 are the best-characterized members among Arf family, we established T lineage-specific Arf1-deficient, Arf6-deficient, and Arf1/6 double-deficient mice to understand physiological roles of the Arf pathway in the immune system. Contrary to our expectation, Arf deficiency had little or no impact on cytokine secretion from the activated T cells. In contrast, the lack of both Arf1 and Arf6, but neither Arf1 nor Arf6 deficiency alone, rendered naive T cells susceptible to apoptosis upon TCR stimulation because of imbalanced expression of Bcl-2 family members. We further demonstrate that Arf1/6 deficiency in T cells alleviates autoimmune diseases like colitis and experimental autoimmune encephalomyelitis, whereas Ab response under Th2-polarizing conditions is seemingly normal. Our findings reveal an unexpected role for the Arf pathway in the survival of T cells during TCR-induced activation and its potential as a therapeutic target in the autoimmune diseases.
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Affiliation(s)
- Mami Sumiyoshi
- Department of Cell Signaling, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
| | - Yui Kotani
- Department of Cell Signaling, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan.,Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Yuki Ikuta
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Kazutomo Suzue
- Department of Parasitology, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Madoka Ozawa
- Department of Immunology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | - Tomoya Katakai
- Department of Immunology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | - Taketo Yamada
- Department of Pathology, Saitama Medical University, Iruma-gun, Saitama 350-0495, Japan
| | - Takaya Abe
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Kana Bando
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Shigeo Koyasu
- Laboratory for Immune Cell Systems, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan; and
| | - Yasunori Kanaho
- Department of Physiological Chemistry, Graduate School of Comprehensive Human Sciences, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Toshio Watanabe
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Satoshi Matsuda
- Department of Cell Signaling, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan;
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18
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Sun X, Shu Y, Xu M, Jiang J, Wang L, Wang J, Huang D, Zhang J. ANXA6 suppresses the tumorigenesis of cervical cancer through autophagy induction. Clin Transl Med 2020; 10:e208. [PMID: 33135350 PMCID: PMC7571625 DOI: 10.1002/ctm2.208] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/18/2020] [Accepted: 10/03/2020] [Indexed: 12/17/2022] Open
Abstract
Background Autophagy is an intracellular degradation pathway conserved in eukaryotes. ANXA6 (annexin A6) belongs to a family of calcium‐dependent membrane and phospholipid‐binding proteins. Here, we identify ANXA6 as a newly synthesized protein in starvation‐induced autophagy and validate it as a novel autophagy modulator that regulates autophagosome formation. Results ANXA6 knockdown attenuates starvation‐induced autophagy, while restoration of its expression enhances autophagy. GO (gene ontology) analysis of ANXA6 targets showed that ANXA6 interacts with many RAB GTPases and targets endocytosis and phagocytosis pathways, indicating that ANXA6 exerts its function through protein trafficking. ATG9A (autophagy‐related 9A) is the sole multispanning transmembrane protein and its trafficking through recycling endosomes is an essential step for autophagosome formation. Our results showed that ANXA6 enables appropriate ATG9A+ vesicle trafficking from endosomes to autophagosomes through RAB proteins or F‐actin. In addition, restoration of ANXA6 expression suppresses mTOR (mammalian target of rapamycin) activity through the inhibition of the PI3K (phosphoinositide 3‐kinase)‐AKT and ERK (extracellular signal‐regulated kinase) signaling pathways, which is a negative regulator of autophagy. Functionally, ANXA6 expression is correlated with LC3 (microtubule‐associated protein 1 light chain 3) expression in cervical cancer, and ANXA6 inhibits tumorigenesis through autophagy induction. Conclusions Our results reveal an important mechanism for ANXA6 in tumor suppression and autophagy regulation.
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Affiliation(s)
- Xin Sun
- Department of Oncology, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Yuhan Shu
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Mengting Xu
- College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Jiukun Jiang
- Department of Emergency Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Liming Wang
- Department of Physiology, National University of Singapore, Singapore, Singapore
| | - Jigang Wang
- Artemisinin Research Center, and Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China.,The First Affiliated Hospital of Southern University of Science and Technology, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China.,Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, China
| | - Dongsheng Huang
- Key Laboratory of Tumor Molecular Diagnosis and Individualized Medicine of Zhejiang Province, People's Hospital of Hangzhou Medical College, Clinical Research Institute, Hangzhou, China
| | - Jianbin Zhang
- Key Laboratory of Tumor Molecular Diagnosis and Individualized Medicine of Zhejiang Province, People's Hospital of Hangzhou Medical College, Clinical Research Institute, Hangzhou, China
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19
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Gao J, Kurre R, Rose J, Walter S, Fröhlich F, Piehler J, Reggiori F, Ungermann C. Function of the SNARE Ykt6 on autophagosomes requires the Dsl1 complex and the Atg1 kinase complex. EMBO Rep 2020; 21:e50733. [PMID: 33025734 PMCID: PMC7726795 DOI: 10.15252/embr.202050733] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 12/11/2022] Open
Abstract
The mechanism and regulation of fusion between autophagosomes and lysosomes/vacuoles are still only partially understood in both yeast and mammals. In yeast, this fusion step requires SNARE proteins, the homotypic vacuole fusion and protein sorting (HOPS) tethering complex, the RAB7 GTPase Ypt7, and its guanine nucleotide exchange factor (GEF) Mon1‐Ccz1. We and others recently identified Ykt6 as the autophagosomal SNARE protein. However, it has not been resolved when and how lipid‐anchored Ykt6 is recruited onto autophagosomes. Here, we show that Ykt6 is recruited at an early stage of the formation of these carriers through a mechanism that depends on endoplasmic reticulum (ER)‐resident Dsl1 complex and COPII‐coated vesicles. Importantly, Ykt6 activity on autophagosomes is regulated by the Atg1 kinase complex, which inhibits Ykt6 through direct phosphorylation. Thus, our findings indicate that the Ykt6 pool on autophagosomal membranes is kept inactive by Atg1 phosphorylation, and once an autophagosome is ready to fuse with vacuole, Ykt6 dephosphorylation allows its engagement in the fusion event.
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Affiliation(s)
- Jieqiong Gao
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Rainer Kurre
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany
| | - Jaqueline Rose
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
| | - Jacob Piehler
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany.,Department of Biology/Chemistry, Biophysics Section, University of Osnabrück, Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
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20
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Mookherjee D, Das S, Mukherjee R, Bera M, Jana SC, Chakrabarti S, Chakrabarti O. RETREG1/FAM134B mediated autophagosomal degradation of AMFR/GP78 and OPA1 -a dual organellar turnover mechanism. Autophagy 2020; 17:1729-1752. [PMID: 32559118 DOI: 10.1080/15548627.2020.1783118] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Turnover of cellular organelles, including endoplasmic reticulum (ER) and mitochondria, is orchestrated by an efficient cellular surveillance system. We have identified a mechanism for dual regulation of ER and mitochondria under stress. It is known that AMFR, an ER E3 ligase and ER-associated degradation (ERAD) regulator, degrades outer mitochondrial membrane (OMM) proteins, MFNs (mitofusins), via the proteasome and triggers mitophagy. We show that destabilized mitochondria are almost devoid of the OMM and generate "mitoplasts". This brings the inner mitochondrial membrane (IMM) in the proximity of the ER. When AMFR levels are high and the mitochondria are stressed, the reticulophagy regulatory protein RETREG1 participates in the formation of the mitophagophore by interacting with OPA1. Interestingly, OPA1 and other IMM proteins exhibit similar RETREG1-dependent autophagosomal degradation as AMFR, unlike most of the OMM proteins. The "mitoplasts" generated are degraded by reticulo-mito-phagy - simultaneously affecting dual organelle turnover.Abbreviations: AMFR/GP78: autocrine motility factor receptor; BAPTA: 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; BFP: blue fluorescent protein; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; CNBr: cyanogen bromide; ER: endoplasmic reticulum; ERAD: endoplasmic-reticulum-associated protein degradation; FL: fluorescence, GFP: green fluorescent protein; HA: hemagglutinin; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; IMM: inner mitochondrial membrane; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MFN: mitofusin, MGRN1: mahogunin ring finger 1; NA: numerical aperature; OMM: outer mitochondrial membrane; OPA1: OPA1 mitochondrial dynamin like GTPase; PRNP/PrP: prion protein; RER: rough endoplasmic reticulum; RETREG1/FAM134B: reticulophagy regulator 1; RFP: red fluorescent protein; RING: really interesting new gene; ROI: region of interest; RTN: reticulon; SEM: standard error of the mean; SER: smooth endoplasmic reticulum; SIM: structured illumination microscopy; SQSTM1/p62: sequestosome 1; STED: stimulated emission depletion; STOML2: stomatin like 2; TOMM20: translocase of outer mitochondrial membrane 20; UPR: unfolded protein response.
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Affiliation(s)
- Debdatto Mookherjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India
| | - Subhrangshu Das
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Rukmini Mukherjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India.,Buchmann Institute for Molecular Life Sciences, Frankfurt Am Main, Germany
| | - Manindra Bera
- Laboratory of Cell Biology, the Rockefeller University, New York, USA
| | | | - Saikat Chakrabarti
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Oishee Chakrabarti
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India.,Homi Bhabha National Institute, Mumbai, India
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21
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Local Fatty Acid Channeling into Phospholipid Synthesis Drives Phagophore Expansion during Autophagy. Cell 2019; 180:135-149.e14. [PMID: 31883797 DOI: 10.1016/j.cell.2019.12.005] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 10/29/2019] [Accepted: 12/04/2019] [Indexed: 12/21/2022]
Abstract
Autophagy is a conserved catabolic homeostasis process central for cellular and organismal health. During autophagy, small single-membrane phagophores rapidly expand into large double-membrane autophagosomes to encapsulate diverse cargoes for degradation. It is thought that autophagic membranes are mainly derived from preformed organelle membranes. Instead, here we delineate a pathway that expands the phagophore membrane by localized phospholipid synthesis. Specifically, we find that the conserved acyl-CoA synthetase Faa1 accumulates on nucleated phagophores and locally activates fatty acids (FAs) required for phagophore elongation and autophagy. Strikingly, using isotopic FA tracing, we directly show that Faa1 channels activated FAs into the synthesis of phospholipids and promotes their assembly into autophagic membranes. Indeed, the first committed steps of de novo phospholipid synthesis at the ER, which forms stable contacts with nascent autophagosomes, are essential for autophagy. Together, our work illuminates how cells spatially tune synthesis and flux of phospholipids for autophagosome biogenesis during autophagy.
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22
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Valionyte E, Yang Y, Roberts SL, Kelly J, Lu B, Luo S. Lowering Mutant Huntingtin Levels and Toxicity: Autophagy-Endolysosome Pathways in Huntington's Disease. J Mol Biol 2019; 432:2673-2691. [PMID: 31786267 DOI: 10.1016/j.jmb.2019.11.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/04/2019] [Accepted: 11/19/2019] [Indexed: 02/06/2023]
Abstract
Huntington's disease (HD) is a monogenetic neurodegenerative disease, which serves as a model of neurodegeneration with protein aggregation. Autophagy has been suggested to possess a great value to tackle protein aggregation toxicity and neurodegenerative diseases. Current studies suggest that autophagy-endolysosomal pathways are critical for HD pathology. Here we review recent advancement in the studies of autophagy and selective autophagy relating HD. Restoration of autophagy flux and enhancement of selective removal of mutant huntingtin/disease-causing protein would be effective approaches towards tackling HD as well as other similar neurodegenerative disorders.
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Affiliation(s)
- Evelina Valionyte
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Yi Yang
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Sheridan L Roberts
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Jack Kelly
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK
| | - Boxun Lu
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Shouqing Luo
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified Medicine, University of Plymouth, Research Way, Plymouth PL6 8BU, UK.
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23
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Cerri S, Blandini F. Role of Autophagy in Parkinson's Disease. Curr Med Chem 2019; 26:3702-3718. [PMID: 29484979 DOI: 10.2174/0929867325666180226094351] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 01/30/2018] [Accepted: 02/13/2018] [Indexed: 12/11/2022]
Abstract
Autophagy is an essential catabolic mechanism that delivers misfolded proteins and damaged organelles to the lysosome for degradation. Autophagy pathways include macroautophagy, chaperone-mediated autophagy and microautophagy, each involving different mechanisms of substrate delivery to lysosome. Defects of these pathways and the resulting accumulation of protein aggregates represent a common pathobiological feature of neurodegenerative disorders such as Alzheimer, Parkinson and Huntington disease. This review provides an overview of the role of autophagy in Parkinson's disease (PD) by summarizing the most relevant genetic and experimental evidence showing how this process can contribute to disease pathogenesis. Given lysosomes take part in the final step of the autophagic process, the role of lysosomal defects in the impairment of autophagy and their impact on disease will also be discussed. A glance on the role of non-neuronal autophagy in the pathogenesis of PD will be included. Moreover, we will examine novel pharmacological targets and therapeutic strategies that, by boosting autophagy, may be theoretically beneficial for PD. Special attention will be focused on natural products, such as phenolic compounds, that are receiving increasing consideration due to their potential efficacy associated with low toxicity. Although many efforts have been made to elucidate autophagic process, the development of new therapeutic interventions requires a deeper understanding of the mechanisms that may lead to autophagy defects in PD and should take into account the multifactorial nature of the disease as well as the phenotypic heterogeneity of PD patients.
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Affiliation(s)
- Silvia Cerri
- Laboratory of Cellular and Molecular Neurobiology, IRCCS Mondino Foundation, Pavia, Italy
| | - Fabio Blandini
- Laboratory of Cellular and Molecular Neurobiology, IRCCS Mondino Foundation, Pavia, Italy
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24
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Abstract
Autophagy is the major cellular pathway to degrade dysfunctional organelles and protein aggregates. Autophagy is particularly important in neurons, which are terminally differentiated cells that must last the lifetime of the organism. There are both constitutive and stress-induced pathways for autophagy in neurons, which catalyze the turnover of aged or damaged mitochondria, endoplasmic reticulum, other cellular organelles, and aggregated proteins. These pathways are required in neurodevelopment as well as in the maintenance of neuronal homeostasis. Here we review the core components of the pathway for autophagosome biogenesis, as well as the cell biology of bulk and selective autophagy in neurons. Finally, we discuss the role of autophagy in neuronal development, homeostasis, and aging and the links between deficits in autophagy and neurodegeneration.
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Affiliation(s)
- Andrea K H Stavoe
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA;
| | - Erika L F Holzbaur
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA;
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25
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Proteomic study of the membrane components of signalling cascades of Botrytis cinerea controlled by phosphorylation. Sci Rep 2019; 9:9860. [PMID: 31285484 PMCID: PMC6614480 DOI: 10.1038/s41598-019-46270-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 06/26/2019] [Indexed: 12/19/2022] Open
Abstract
Protein phosphorylation and membrane proteins play an important role in the infection of plants by phytopathogenic fungi, given their involvement in signal transduction cascades. Botrytis cinerea is a well-studied necrotrophic fungus taken as a model organism in fungal plant pathology, given its broad host range and adverse economic impact. To elucidate relevant events during infection, several proteomics analyses have been performed in B. cinerea, but they cover only 10% of the total proteins predicted in the genome database of this fungus. To increase coverage, we analysed by LC-MS/MS the first-reported overlapped proteome in phytopathogenic fungi, the "phosphomembranome" of B. cinerea, combining the two most important signal transduction subproteomes. Of the 1112 membrane-associated phosphoproteins identified, 64 and 243 were classified as exclusively identified or overexpressed under glucose and deproteinized tomato cell wall conditions, respectively. Seven proteins were found under both conditions, but these presented a specific phosphorylation pattern, so they were considered as exclusively identified or overexpressed proteins. From bioinformatics analysis, those differences in the membrane-associated phosphoproteins composition were associated with various processes, including pyruvate metabolism, unfolded protein response, oxidative stress response, autophagy and cell death. Our results suggest these proteins play a significant role in the B. cinerea pathogenic cycle.
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Cousin MA, Conboy E, Wang JS, Lenz D, Schwab TL, Williams M, Abraham RS, Barnett S, El-Youssef M, Graham RP, Gutierrez Sanchez LH, Hasadsri L, Hoffmann GF, Hull NC, Kopajtich R, Kovacs-Nagy R, Li JQ, Marx-Berger D, McLin V, McNiven MA, Mounajjed T, Prokisch H, Rymen D, Schulze RJ, Staufner C, Yang Y, Clark KJ, Lanpher BC, Klee EW. RINT1 Bi-allelic Variations Cause Infantile-Onset Recurrent Acute Liver Failure and Skeletal Abnormalities. Am J Hum Genet 2019; 105:108-121. [PMID: 31204009 DOI: 10.1016/j.ajhg.2019.05.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 05/13/2019] [Indexed: 01/12/2023] Open
Abstract
Pediatric acute liver failure (ALF) is life threatening with genetic, immunologic, and environmental etiologies. Approximately half of all cases remain unexplained. Recurrent ALF (RALF) in infants describes repeated episodes of severe liver injury with recovery of hepatic function between crises. We describe bi-allelic RINT1 alterations as the cause of a multisystem disorder including RALF and skeletal abnormalities. Three unrelated individuals with RALF onset ≤3 years of age have splice alterations at the same position (c.1333+1G>A or G>T) in trans with a missense (p.Ala368Thr or p.Leu370Pro) or in-frame deletion (p.Val618_Lys619del) in RINT1. ALF episodes are concomitant with fever/infection and not all individuals have complete normalization of liver function testing between episodes. Liver biopsies revealed nonspecific liver damage including fibrosis, steatosis, or mild increases in Kupffer cells. Skeletal imaging revealed abnormalities affecting the vertebrae and pelvis. Dermal fibroblasts showed splice-variant mediated skipping of exon 9 leading to an out-of-frame product and nonsense-mediated transcript decay. Fibroblasts also revealed decreased RINT1 protein, abnormal Golgi morphology, and impaired autophagic flux compared to control. RINT1 interacts with NBAS, recently implicated in RALF, and UVRAG, to facilitate Golgi-to-ER retrograde vesicle transport. During nutrient depletion or infection, Golgi-to-ER transport is suppressed and autophagy is promoted through UVRAG regulation by mTOR. Aberrant autophagy has been associated with the development of similar skeletal abnormalities and also with liver disease, suggesting that disruption of these RINT1 functions may explain the liver and skeletal findings. Clarifying the pathomechanism underlying this gene-disease relationship may inform therapeutic opportunities.
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Adnan M, Islam W, Zhang J, Zheng W, Lu GD. Diverse Role of SNARE Protein Sec22 in Vesicle Trafficking, Membrane Fusion, and Autophagy. Cells 2019; 8:E337. [PMID: 30974782 PMCID: PMC6523435 DOI: 10.3390/cells8040337] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 01/09/2023] Open
Abstract
Protein synthesis begins at free ribosomes or ribosomes attached with the endoplasmic reticulum (ER). Newly synthesized proteins are transported to the plasma membrane for secretion through conventional or unconventional pathways. In conventional protein secretion, proteins are transported from the ER lumen to Golgi lumen and through various other compartments to be secreted at the plasma membrane, while unconventional protein secretion bypasses the Golgi apparatus. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins are involved in cargo vesicle trafficking and membrane fusion. The ER localized vesicle associated SNARE (v-SNARE) protein Sec22 plays a major role during anterograde and retrograde transport by promoting efficient membrane fusion and assisting in the assembly of higher order complexes by homodimer formation. Sec22 is not only confined to ER-Golgi intermediate compartments (ERGIC) but also facilitates formation of contact sites between ER and plasma membranes. Sec22 mutation is responsible for the development of atherosclerosis and symptoms in the brain in Alzheimer's disease and aging in humans. In the fruit fly Drosophila melanogaster, Sec22 is essential for photoreceptor morphogenesis, the wingless signaling pathway, and normal ER, Golgi, and endosome morphology. In the plant Arabidopsis thaliana, it is involved in development, and in the nematode Caenorhabditis elegans, it is in involved in the RNA interference (RNAi) pathway. In filamentous fungi, it affects cell wall integrity, growth, reproduction, pathogenicity, regulation of reactive oxygen species (ROS), expression of extracellular enzymes, and transcriptional regulation of many development related genes. This review provides a detailed account of Sec22 function, summarizes its domain structure, discusses its genetic redundancy with Ykt6, discusses what is known about its localization to discrete membranes, its contributions in conventional and unconventional autophagy, and a variety of other roles across different cellular systems ranging from higher to lower eukaryotes, and highlights some of the surprises that have originated from research on Sec22.
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Affiliation(s)
- Muhammad Adnan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, and Key Laboratory of Bio-pesticides and Chemical Biology Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Waqar Islam
- College of Geographical Sciences, Fujian Normal University, Fuzhou 350007, Fujian, China.
| | - Jing Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, and Key Laboratory of Bio-pesticides and Chemical Biology Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Wenhui Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, and Key Laboratory of Bio-pesticides and Chemical Biology Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Guo-Dong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, and Key Laboratory of Bio-pesticides and Chemical Biology Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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28
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Ding X, Jiang X, Tian R, Zhao P, Li L, Wang X, Chen S, Zhu Y, Mei M, Bao S, Liu W, Tang Z, Sun Q. RAB2 regulates the formation of autophagosome and autolysosome in mammalian cells. Autophagy 2019; 15:1774-1786. [PMID: 30957628 PMCID: PMC6735470 DOI: 10.1080/15548627.2019.1596478] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Multiple sources contribute membrane and protein machineries to construct functional macroautophagic/autophagic structures. However, the underlying molecular mechanisms remain elusive. Here, we show that RAB2 connects the Golgi network to autophagy pathway by delivering membrane and by sequentially engaging distinct autophagy machineries. In unstressed cells, RAB2 resides primarily in the Golgi apparatus, as evidenced by its interaction and colocalization with GOLGA2/GM130. Importantly, autophagy stimuli dissociate RAB2 from GOLGA2 to interact with ULK1 complex, which facilitates the recruitment of ULK1 complex to form phagophores. Intriguingly, RAB2 appears to modulate ULK1 kinase activity to propagate signals for autophagosome formation. Subsequently, RAB2 switches to interact with autophagosomal RUBCNL/PACER and STX17 to further specify the recruitment of HOPS complex for autolysosome formation. Together, our study reveals a multivalent pathway in bulk autophagy regulation, and provides mechanistic insights into how the Golgi apparatus contributes to the formation of different autophagic structures. Abbreviations: ACTB: actin beta; ATG9: autophagy related 9A; ATG14: autophagy related 14; ATG16L1: autophagy related 16 like 1; BCAP31: B cell receptor associated protein 31; BECN1: beclin 1; Ctrl: control; CQ: chloroquine; CTSD: cathepsin D; DMSO: dimethyl sulfoxide; EBSS: Earle’s balanced salt solution; EEA1: early endosome antigen 1; GDI: guanine nucleotide dissociation inhibitor; GFP: green fluorescent protein; GOLGA2: golgin A2; HOPS: homotypic fusion and protein sorting complex; IP: immunoprecipitation; KD: knockdown; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LC3: microtubule-associated protein 1 light chain 3; OE: overexpression; PtdIns3K: class III phosphatidylinositol 3-kinase; SQSTM1/p62: sequestosome 1; RAB2: RAB2A, member RAS oncogene family; RAB7: RAB7A, member RAS oncogene family; RAB11: RAB11A, member RAS oncogene family; RUBCNL/PACER: rubicon like autophagy enhancer; STX17: syntaxin 17; TBC1D14: TBC1 domain family member 14; TFRC: transferrin receptor; TGOLN2: trans-golgi network protein 2; TUBB: tubulin beta class I; ULK1: unc-51 like autophagy activating kinase 1; VPS41: VPS41, HOPS complex subunit; WB: western blot; WT: wild type; YPT1: GTP-binding protein YPT1.
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Affiliation(s)
- Xianming Ding
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou , China
| | - Xiao Jiang
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou , China
| | - Rui Tian
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou , China
| | - Pengwei Zhao
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou , China
| | - Lin Li
- Proteomics Center, National Institute of Biological Sciences , Beijing , China
| | - Xinyi Wang
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou , China
| | - She Chen
- Proteomics Center, National Institute of Biological Sciences , Beijing , China
| | - Yushan Zhu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Sciences, College of Life Sciences, Nankai University , Tianjin , China
| | - Mei Mei
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences , Beijing , China
| | - Shilai Bao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences , Beijing , China
| | - Wei Liu
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou , China
| | - Zaiming Tang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiao Tong University , Shanghai , China
| | - Qiming Sun
- Department of Biochemistry, and Department of Cardiology of Second Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou , China
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29
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Shima T, Kirisako H, Nakatogawa H. COPII vesicles contribute to autophagosomal membranes. J Cell Biol 2019; 218:1503-1510. [PMID: 30787039 PMCID: PMC6504894 DOI: 10.1083/jcb.201809032] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/11/2019] [Accepted: 02/05/2019] [Indexed: 01/03/2023] Open
Abstract
The membrane dynamics underlying the biogenesis of autophagosomes, including the origin of the autophagosomal membrane, are still elusive. Shima et al. use a recently developed COPII vesicle–labeling system to show that COPII vesicles are a membrane source in autophagosome formation. A hallmark of autophagy is the de novo formation of double-membrane vesicles called autophagosomes, which sequester various cellular constituents for degradation in lysosomes or vacuoles. The membrane dynamics underlying the biogenesis of autophagosomes, including the origin of the autophagosomal membrane, are still elusive. Although previous studies suggested that COPII vesicles are closely associated with autophagosome biogenesis, it remains unclear whether these vesicles serve as a source of the autophagosomal membrane. Using a recently developed COPII vesicle–labeling system in fluorescence and immunoelectron microscopy in the budding yeast Saccharomyces cerevisiae, we show that the transmembrane cargo Axl2 is loaded into COPII vesicles in the ER. Axl2 is then transferred to autophagosome intermediates, ultimately becoming part of autophagosomal membranes. This study provides a definitive answer to a long-standing, fundamental question regarding the mechanisms of autophagosome formation by implicating COPII vesicles as a membrane source for autophagosomes.
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Affiliation(s)
- Takayuki Shima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiromi Kirisako
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hitoshi Nakatogawa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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30
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Abstract
Macroautophagy (hereafter autophagy) is a catabolic pathway present in all eukaryotic cells. The yeast Saccharomyces cerevisiae has been pivotal in the identification and characterization of the key autophagy-related (Atg) proteins, which play a central role in the generation of autophagosomes. The components of the core Atg/ATG machinery and their functions are highly conserved among species, although mammalian cells also have isoforms and auxiliary factors. Atg9/ATG9 is the only transmembrane protein that is part of the core Atg/ATG machinery, but it appears to have divergent localizations and molecular roles in yeast and mammals. A recent experimental analysis of the yeast endo-lysosomal system by the laboratory of Benjamin Glick, however, suggests a more simple organization of this membrane system. Although this study has not examined yeast Atg9, its findings place this protein in the same compartments as its mammalian counterpart. Here, we will discuss the implications of this conceptual change on the trafficking of yeast Atg9 and its function in autophagy.
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Affiliation(s)
- Christian Ungermann
- a Department of Biology/Chemistry, Biochemistry section , University of Osnabrück , Osnabrück , Germany
| | - Fulvio Reggiori
- b Department of Cell Biology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
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31
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Ryan TA, Tumbarello DA. Optineurin: A Coordinator of Membrane-Associated Cargo Trafficking and Autophagy. Front Immunol 2018; 9:1024. [PMID: 29867991 PMCID: PMC5962687 DOI: 10.3389/fimmu.2018.01024] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/24/2018] [Indexed: 12/13/2022] Open
Abstract
Optineurin is a multifunctional adaptor protein intimately involved in various vesicular trafficking pathways. Through interactions with an array of proteins, such as myosin VI, huntingtin, Rab8, and Tank-binding kinase 1, as well as via its oligomerisation, optineurin has the ability to act as an adaptor, scaffold, or signal regulator to coordinate many cellular processes associated with the trafficking of membrane-delivered cargo. Due to its diverse interactions and its distinct functions, optineurin is an essential component in a number of homeostatic pathways, such as protein trafficking and organelle maintenance. Through the binding of polyubiquitinated cargoes via its ubiquitin-binding domain, optineurin also serves as a selective autophagic receptor for the removal of a wide range of substrates. Alternatively, it can act in an ubiquitin-independent manner to mediate the clearance of protein aggregates. Regarding its disease associations, mutations in the optineurin gene are associated with glaucoma and have more recently been found to correlate with Paget’s disease of bone and amyotrophic lateral sclerosis (ALS). Indeed, ALS-associated mutations in optineurin result in defects in neuronal vesicular localisation, autophagosome–lysosome fusion, and secretory pathway function. More recent molecular and functional analysis has shown that it also plays a role in mitophagy, thus linking it to a number of other neurodegenerative conditions, such as Parkinson’s. Here, we review the role of optineurin in intracellular membrane trafficking, with a focus on autophagy, and describe how upstream signalling cascades are critical to its regulation. Current data and contradicting reports would suggest that optineurin is an important and selective autophagy receptor under specific conditions, whereby interplay, synergy, and functional redundancy with other receptors occurs. We will also discuss how dysfunction in optineurin-mediated pathways may lead to perturbation of critical cellular processes, which can drive the pathologies of number of diseases. Therefore, further understanding of optineurin function, its target specificity, and its mechanism of action will be critical in fully delineating its role in human disease.
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Affiliation(s)
- Thomas A Ryan
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - David A Tumbarello
- Biological Sciences, University of Southampton, Southampton, United Kingdom
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32
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Bustamante HA, González AE, Cerda-Troncoso C, Shaughnessy R, Otth C, Soza A, Burgos PV. Interplay Between the Autophagy-Lysosomal Pathway and the Ubiquitin-Proteasome System: A Target for Therapeutic Development in Alzheimer's Disease. Front Cell Neurosci 2018; 12:126. [PMID: 29867359 PMCID: PMC5954036 DOI: 10.3389/fncel.2018.00126] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/20/2018] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common cause of age-related dementia leading to severe irreversible cognitive decline and massive neurodegeneration. While therapeutic approaches for managing symptoms are available, AD currently has no cure. AD associates with a progressive decline of the two major catabolic pathways of eukaryotic cells—the autophagy-lysosomal pathway (ALP) and the ubiquitin-proteasome system (UPS)—that contributes to the accumulation of harmful molecules implicated in synaptic plasticity and long-term memory impairment. One protein recently highlighted as the earliest initiator of these disturbances is the amyloid precursor protein (APP) intracellular C-terminal membrane fragment β (CTFβ), a key toxic agent with deleterious effects on neuronal function that has become an important pathogenic factor for AD and a potential biomarker for AD patients. This review focuses on the involvement of regulatory molecules and specific post-translational modifications (PTMs) that operate in the UPS and ALP to control a single proteostasis network to achieve protein balance. We discuss how these aspects can contribute to the development of novel strategies to strengthen the balance of key pathogenic proteins associated with AD.
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Affiliation(s)
- Hianara A Bustamante
- Institute of Physiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile.,Center for Interdisciplinary Studies on the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Alexis E González
- Institute of Physiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile.,Fundación Ciencia y Vida, Santiago, Chile
| | - Cristobal Cerda-Troncoso
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Ronan Shaughnessy
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.,Center for Aging and Regeneration (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carola Otth
- Center for Interdisciplinary Studies on the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile.,Institute of Clinical Microbiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Andrea Soza
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.,Center for Aging and Regeneration (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Patricia V Burgos
- Institute of Physiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile.,Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.,Center for Aging and Regeneration (CARE), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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33
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Bingol B. Autophagy and lysosomal pathways in nervous system disorders. Mol Cell Neurosci 2018; 91:167-208. [PMID: 29729319 DOI: 10.1016/j.mcn.2018.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 04/26/2018] [Accepted: 04/28/2018] [Indexed: 12/12/2022] Open
Abstract
Autophagy is an evolutionarily conserved pathway for delivering cytoplasmic cargo to lysosomes for degradation. In its classically studied form, autophagy is a stress response induced by starvation to recycle building blocks for essential cellular processes. In addition, autophagy maintains basal cellular homeostasis by degrading endogenous substrates such as cytoplasmic proteins, protein aggregates, damaged organelles, as well as exogenous substrates such as bacteria and viruses. Given their important role in homeostasis, autophagy and lysosomal machinery are genetically linked to multiple human disorders such as chronic inflammatory diseases, cardiomyopathies, cancer, and neurodegenerative diseases. Multiple targets within the autophagy and lysosomal pathways offer therapeutic opportunities to benefit patients with these disorders. Here, I will summarize the mechanisms of autophagy pathways, the evidence supporting a pathogenic role for disturbed autophagy and lysosomal degradation in nervous system disorders, and the therapeutic potential of autophagy modulators in the clinic.
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Affiliation(s)
- Baris Bingol
- Genentech, Inc., Department of Neuroscience, 1 DNA Way, South San Francisco 94080, United States.
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34
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Vigié P, Cougouilles E, Bhatia-Kiššová I, Salin B, Blancard C, Camougrand N. Mitochondrial phosphatidylserine decarboxylase 1 (Psd1) is involved in nitrogen starvation-induced mitophagy in yeast. J Cell Sci 2018; 132:jcs.221655. [DOI: 10.1242/jcs.221655] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 11/26/2018] [Indexed: 12/28/2022] Open
Abstract
Mitophagy, the selective degradation of mitochondria by autophagy, is a central process essential to maintain cell homeostasis. It is implicated in the clearance of superfluous or damaged mitochondria and requires specific proteins and regulators to perform. In yeast, Atg32, an outer mitochondrial membrane protein, interacts with the ubiquitin-like Atg8 protein, promoting the recruitment of mitochondria to the phagophore and their sequestration within autophagosomes. Atg8 is anchored to the phagophore and autophagosome membranes thanks to a phosphatidylethanolamine tail. In yeast, several phosphatidylethanolamine synthesis pathways have been characterized, but their contribution to autophagy and mitophagy are unknown. Through different approaches, we show that Psd1, the mitochondrial phosphatidylserine decarboxylase, is involved only in mitophagy induction in nitrogen starvation, whereas Psd2, located in vacuole/Golgi apparatus/endosome membranes, is required preferentially for mitophagy induction in the stationary phase of growth but also to a lesser extent for nitrogen starvation-induced mitophagy. Our results suggest that Δpsd1 mitophagy defect in nitrogen starvation may be due to a failure of Atg8 recruitment to mitochondria.
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Affiliation(s)
- Pierre Vigié
- CNRS, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
- Université de Bordeaux, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
| | - Elodie Cougouilles
- CNRS, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
- Université de Bordeaux, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
| | - Ingrid Bhatia-Kiššová
- Comenius University, Faculty of Natural Sciences, Department of Biochemistry, Mlynská dolina CH1, 84215 Bratislava, Slovak Republic
| | - Bénédicte Salin
- CNRS, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
- Université de Bordeaux, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
| | - Corinne Blancard
- CNRS, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
- Université de Bordeaux, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
| | - Nadine Camougrand
- CNRS, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
- Université de Bordeaux, UMR5095, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France
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35
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Host-pathogen interactions and subversion of autophagy. Essays Biochem 2017; 61:687-697. [PMID: 29233878 PMCID: PMC5869863 DOI: 10.1042/ebc20170058] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/26/2017] [Accepted: 11/01/2017] [Indexed: 12/17/2022]
Abstract
Macroautophagy (‘autophagy’), is the process by which cells can form a double-membraned vesicle that encapsulates material to be degraded by the lysosome. This can include complex structures such as damaged mitochondria, peroxisomes, protein aggregates and large swathes of cytoplasm that can not be processed efficiently by other means of degradation. Recycling of amino acids and lipids through autophagy allows the cell to form intracellular pools that aid survival during periods of stress, including growth factor deprivation, amino acid starvation or a depleted oxygen supply. One of the major functions of autophagy that has emerged over the last decade is its importance as a safeguard against infection. The ability of autophagy to selectively target intracellular pathogens for destruction is now regarded as a key aspect of the innate immune response. However, pathogens have evolved mechanisms to either evade or reconfigure the autophagy pathway for their own survival. Understanding how pathogens interact with and manipulate the host autophagy pathway will hopefully provide a basis for combating infection and increase our understanding of the role and regulation of autophagy. Herein, we will discuss how the host cell can identify and target invading pathogens and how pathogens have adapted in order to evade destruction by the host cell. In particular, we will focus on interactions between the mammalian autophagy gene 8 (ATG8) proteins and the host and pathogen effector proteins.
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36
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Baron O, Boudi A, Dias C, Schilling M, Nölle A, Vizcay-Barrena G, Rattray I, Jungbluth H, Scheper W, Fleck RA, Bates GP, Fanto M. Stall in Canonical Autophagy-Lysosome Pathways Prompts Nucleophagy-Based Nuclear Breakdown in Neurodegeneration. Curr Biol 2017; 27:3626-3642.e6. [PMID: 29174892 PMCID: PMC5723708 DOI: 10.1016/j.cub.2017.10.054] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 09/19/2017] [Accepted: 10/20/2017] [Indexed: 12/31/2022]
Abstract
The terminal stages of neuronal degeneration and death in neurodegenerative diseases remain elusive. Autophagy is an essential catabolic process frequently failing in neurodegeneration. Selective autophagy routes have recently emerged, including nucleophagy, defined as degradation of nuclear components by autophagy. Here, we show that, in a mouse model for the polyglutamine disease dentatorubral-pallidoluysian atrophy (DRPLA), progressive acquirement of an ataxic phenotype is linked to severe cerebellar cellular pathology, characterized by nuclear degeneration through nucleophagy-based LaminB1 degradation and excretion. We find that canonical autophagy is stalled in DRPLA mice and in human fibroblasts from patients of DRPLA. This is evidenced by accumulation of p62 and downregulation of LC3-I/II conversion as well as reduced Tfeb expression. Chronic autophagy blockage in several conditions, including DRPLA and Vici syndrome, an early-onset autolysosomal pathology, leads to the activation of alternative clearance pathways including Golgi membrane-associated and nucleophagy-based LaminB1 degradation and excretion. The combination of these alternative pathways and canonical autophagy blockade, results in dramatic nuclear pathology with disruption of the nuclear organization, bringing about terminal cell atrophy and degeneration. Thus, our findings identify a novel progressive mechanism for the terminal phases of neuronal cell degeneration and death in human neurodegenerative diseases and provide a link between autophagy block, activation of alternative pathways for degradation, and excretion of cellular components.
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Affiliation(s)
- Olga Baron
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, UK
| | - Adel Boudi
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, UK
| | - Catarina Dias
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, UK
| | - Michael Schilling
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, UK
| | - Anna Nölle
- Department of Clinical Genetics and Alzheimer Center, VU University Medical Center, Amsterdam, the Netherlands; Department of Functional Genome Analysis, VU University, Amsterdam, the Netherlands
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, King's College London, SE1 1UL London, UK
| | - Ivan Rattray
- Department Medical and Molecular Genetics, School of Basic and Biomedical Sciences, King's College London, SE1 9RT London, UK
| | - Heinz Jungbluth
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, UK; Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Randall Division for Cell and Molecular Biophysics, Muscle Signaling Section, King's College London, London, UK
| | - Wiep Scheper
- Department of Clinical Genetics and Alzheimer Center, VU University Medical Center, Amsterdam, the Netherlands; Department of Functional Genome Analysis, VU University, Amsterdam, the Netherlands
| | - Roland A Fleck
- Centre for Ultrastructural Imaging, King's College London, SE1 1UL London, UK
| | - Gillian P Bates
- Department Medical and Molecular Genetics, School of Basic and Biomedical Sciences, King's College London, SE1 9RT London, UK; Sobell Department of Motor Neuroscience, UCL Institute of Neurology, WC1N 3BG London, UK
| | - Manolis Fanto
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, UK.
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Zou S, Sun D, Liang Y. The Roles of the SNARE Protein Sed5 in Autophagy in Saccharomyces cerevisiae. Mol Cells 2017; 40:643-654. [PMID: 28927260 PMCID: PMC5638772 DOI: 10.14348/molcells.2017.0030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/10/2017] [Accepted: 07/19/2017] [Indexed: 12/15/2022] Open
Abstract
Autophagy is a degradation pathway in eukaryotic cells in which aging proteins and organelles are sequestered into double-membrane vesicles, termed autophagosomes, which fuse with vacuoles to hydrolyze cargo. The key step in autophagy is the formation of autophagosomes, which requires different kinds of vesicles, including COPII vesicles and Atg9-containing vesicles, to transport lipid double-membranes to the phagophore assembly site (PAS). In yeast, the cis-Golgi localized t-SNARE protein Sed5 plays a role in endoplasmic reticulum (ER)-Golgi and intra-Golgi vesicular transport. We report that during autophagy, sed5-1 mutant cells could not properly transport Atg8 to the PAS, resulting in multiple Atg8 dots being dispersed into the cytoplasm. Some dots were trapped in the Golgi apparatus. Sed5 regulates the antero-grade trafficking of Atg9-containing vesicles to the PAS by participating in the localization of Atg23 and Atg27 to the Golgi apparatus. Furthermore, we found that overexpression of SFT1 or SFT2 (suppressor of sed5 ts) rescued the autophagy defects in sed5-1 mutant cells. Our data suggest that Sed5 plays a novel role in autophagy, by regulating the formation of Atg9-containing vesicles in the Golgi apparatus, and the genetic interaction between Sft1/2 and Sed5 is essential for autophagy.
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Affiliation(s)
- Shenshen Zou
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095,
China
| | - Dan Sun
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095,
China
| | - Yongheng Liang
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095,
China
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Abstract
Macroautophagy is an intracellular pathway used for targeting of cellular components to the lysosome for their degradation and involves sequestration of cytoplasmic material into autophagosomes formed from a double membrane structure called the phagophore. The nucleation and elongation of the phagophore is tightly regulated by several autophagy-related (ATG) proteins, but also involves vesicular trafficking from different subcellular compartments to the forming autophagosome. Such trafficking must be tightly regulated by various intra- and extracellular signals to respond to different cellular stressors and metabolic states, as well as the nature of the cargo to become degraded. We are only starting to understand the interconnections between different membrane trafficking pathways and macroautophagy. This review will focus on the membrane trafficking machinery found to be involved in delivery of membrane, lipids, and proteins to the forming autophagosome and in the subsequent autophagosome fusion with endolysosomal membranes. The role of RAB proteins and their regulators, as well as coat proteins, vesicle tethers, and SNARE proteins in autophagosome biogenesis and maturation will be discussed.
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Wang IH, Chen YJ, Hsu JW, Lee FJ. The Arl3 and Arl1 GTPases co-operate with Cog8 to regulate selective autophagy via Atg9 trafficking. Traffic 2017. [PMID: 28627726 DOI: 10.1111/tra.12498] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The Arl3-Arl1 GTPase cascade plays important roles in vesicle trafficking at the late Golgi and endosomes. Subunits of the conserved oligomeric Golgi (COG) complex, a tethering factor, are important for endosome-to-Golgi transport and contribute to the efficient functioning of the cytoplasm-to-vacuole targeting (Cvt) pathway, a well-known selective autophagy pathway. According to our findings, the Arl3-Arl1 GTPase cascade co-operates with Cog8 to regulate the Cvt pathway via Atg9 trafficking. arl3cog8Δ and arl1cog8Δ exhibit profound defects in aminopeptidase I maturation in rich medium. In addition, the Arl3-Arl1 cascade acts on the Cvt pathway via dynamic nucleotide binding. Furthermore, Atg9 accumulates at the late Golgi in arl3cog8Δ and arl1cog8Δ cells under normal growth conditions but not under starvation conditions. Thus, our results offer insight into the requirement for multiple components in the Golgi-endosome system to determine Atg9 trafficking at the Golgi, thereby regulating selective autophagy.
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Affiliation(s)
- I-Hao Wang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Jie Chen
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jia-Wei Hsu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Fang Jen Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
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40
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Xiang G, Yang L, Long Q, Chen K, Tang H, Wu Y, Liu Z, Zhou Y, Qi J, Zheng L, Liu W, Ying Z, Fan W, Shi H, Li H, Lin X, Gao M, Liu J, Bao F, Li L, Duan L, Li M, Liu X. BNIP3L-dependent mitophagy accounts for mitochondrial clearance during 3 factors-induced somatic cell reprogramming. Autophagy 2017; 13:1543-1555. [PMID: 28722510 DOI: 10.1080/15548627.2017.1338545] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Induced pluripotent stem cells (iPSCs) have fewer and immature mitochondria than somatic cells and mainly rely on glycolysis for energy source. During somatic cell reprogramming, somatic mitochondria and other organelles get remodeled. However, events of organelle remodeling and interaction during somatic cell reprogramming have not been extensively explored. We show that both SKP/SKO (Sox2, Klf4, Pou5f1/Oct4) and SKPM/SKOM (SKP/SKO plus Myc/c-Myc) reprogramming lead to decreased mitochondrial mass but with different kinetics and by divergent pathways. Rapid, MYC/c-MYC-induced cell proliferation may function as the main driver of mitochondrial decrease in SKPM/SKOM reprogramming. In SKP/SKO reprogramming, however, mitochondrial mass initially increases and subsequently decreases via mitophagy. This mitophagy is dependent on the mitochondrial outer membrane receptor BNIP3L/NIX but not on mitochondrial membrane potential (ΔΨm) dissipation, and this SKP/SKO-induced mitophagy functions in an important role during the reprogramming process. Furthermore, endosome-related RAB5 is involved in mitophagosome formation in SKP/SKO reprogramming. These results reveal a novel role of mitophagy in reprogramming that entails the interaction between mitochondria, macroautophagy/autophagy and endosomes.
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Affiliation(s)
- Ge Xiang
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Liang Yang
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Qi Long
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Keshi Chen
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Haite Tang
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Yi Wu
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Zihuang Liu
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Yanshuang Zhou
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Juntao Qi
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Lingjun Zheng
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China.,c Institute of Health Sciences , Anhui University , Hefei , China
| | - Wenbo Liu
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Zhongfu Ying
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Weimin Fan
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Hongyan Shi
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China.,c Institute of Health Sciences , Anhui University , Hefei , China
| | - Hongmei Li
- d School of Life Sciences , Sun Yat-sen University , Guangzhou , China
| | - Xiaobing Lin
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Mi Gao
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Jinglei Liu
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Feixiang Bao
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Linpeng Li
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Lifan Duan
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
| | - Min Li
- e School of Pharmaceutical Sciences , Sun Yat-Sen University , Guangzhou , China
| | - Xingguo Liu
- a CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health , Chinese Academy of Sciences , Guangzhou , China ; Guangzhou Medical University , Guangzhou , China.,b Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Guangzhou , China
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Lee MH, Yoo YJ, Kim DH, Hanh NH, Kwon Y, Hwang I. The Prenylated Rab GTPase Receptor PRA1.F4 Contributes to Protein Exit from the Golgi Apparatus. PLANT PHYSIOLOGY 2017; 174:1576-1594. [PMID: 28487479 PMCID: PMC5490915 DOI: 10.1104/pp.17.00466] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/04/2017] [Indexed: 05/28/2023]
Abstract
Prenylated Rab acceptor1 (PRA1) functions in the recruitment of prenylated Rab proteins to their cognate organelles. Arabidopsis (Arabidopsis thaliana) contains a large number of proteins belonging to the AtPRA1 family. However, their physiological roles remain largely unknown. Here, we investigated the physiological role of AtPRA1.F4, a member of the AtPRA1 family. A T-DNA insertion knockdown mutant of AtPRA1.F4, atpra1.f4, was smaller in stature than parent plants and possessed shorter roots, whereas transgenic plants overexpressing HA:AtPRA1.F4 showed enhanced development of secondary roots and root hairs. However, both overexpression and knockdown plants exhibited increased sensitivity to high-salt stress, lower vacuolar Na+/K+-ATPase and plasma membrane ATPase activities, lower and higher pH in the vacuole and apoplast, respectively, and highly vesiculated Golgi apparatus. HA:AtPRA1.F4 localized to the Golgi apparatus and assembled into high-molecular-weight complexes. atpra1.f4 plants displayed a defect in vacuolar trafficking, which was complemented by low but not high levels of HA:AtPRA1.F4 Overexpression of HA:AtPRA1.F4 also inhibited protein trafficking at the Golgi apparatus, albeit differentially depending on the final destination or type of protein: trafficking of vacuolar proteins, plasma membrane proteins, and trans-Golgi network (TGN)-localized SYP61 was strongly inhibited; trafficking of TGN-localized SYP51 was slightly inhibited; and trafficking of secretory proteins and TGN-localized SYP41 was negligibly or not significantly inhibited. Based on these results, we propose that Golgi-localized AtPRA1.F4 is involved in the exit of many but not all types of post-Golgi proteins from the Golgi apparatus. Additionally, an appropriate level of AtPRA1.F4 is crucial for its function at the Golgi apparatus.
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Affiliation(s)
- Myoung Hui Lee
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Yun-Joo Yoo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Dae Heon Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Nguyen Hong Hanh
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Yun Kwon
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Inhwan Hwang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
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42
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Reggiori F, Ungermann C. Autophagosome Maturation and Fusion. J Mol Biol 2017; 429:486-496. [DOI: 10.1016/j.jmb.2017.01.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/03/2017] [Accepted: 01/04/2017] [Indexed: 02/07/2023]
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Gómez-Sánchez R, Sánchez-Wandelmer J, Reggiori F. Monitoring the Formation of Autophagosomal Precursor Structures in Yeast Saccharomyces cerevisiae. Methods Enzymol 2017; 588:323-365. [DOI: 10.1016/bs.mie.2016.09.085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Shi B, Huang QQ, Birkett R, Doyle R, Dorfleutner A, Stehlik C, He C, Pope RM. SNAPIN is critical for lysosomal acidification and autophagosome maturation in macrophages. Autophagy 2016; 13:285-301. [PMID: 27929705 DOI: 10.1080/15548627.2016.1261238] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
We previously observed that SNAPIN, which is an adaptor protein in the SNARE core complex, was highly expressed in rheumatoid arthritis synovial tissue macrophages, but its role in macrophages and autoimmunity is unknown. To identify SNAPIN's role in these cells, we employed siRNA to silence the expression of SNAPIN in primary human macrophages. Silencing SNAPIN resulted in swollen lysosomes with impaired CTSD (cathepsin D) activation, although total CTSD was not reduced. Neither endosome cargo delivery nor lysosomal fusion with endosomes or autophagosomes was inhibited following the forced silencing of SNAPIN. The acidification of lysosomes and accumulation of autolysosomes in SNAPIN-silenced cells was inhibited, resulting in incomplete lysosomal hydrolysis and impaired macroautophagy/autophagy flux. Mechanistic studies employing ratiometric color fluorescence on living cells demonstrated that the reduction of SNAPIN resulted in a modest reduction of H+ pump activity; however, the more critical mechanism was a lysosomal proton leak. Overall, our results demonstrate that SNAPIN is critical in the maintenance of healthy lysosomes and autophagy through its role in lysosome acidification and autophagosome maturation in macrophages largely through preventing proton leak. These observations suggest an important role for SNAPIN and autophagy in the homeostasis of macrophages, particularly long-lived tissue resident macrophages.
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Affiliation(s)
- Bo Shi
- a Division of Rheumatology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
| | - Qi-Quan Huang
- a Division of Rheumatology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
| | - Robert Birkett
- a Division of Rheumatology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
| | - Renee Doyle
- a Division of Rheumatology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
| | - Andrea Dorfleutner
- a Division of Rheumatology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
| | - Christian Stehlik
- a Division of Rheumatology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
| | - Congcong He
- b Department of Cell and Molecular Biology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
| | - Richard M Pope
- a Division of Rheumatology , Feinberg School of Medicine, Northwestern University , Chicago , IL , USA
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Tábara LC, Escalante R. VMP1 Establishes ER-Microdomains that Regulate Membrane Contact Sites and Autophagy. PLoS One 2016; 11:e0166499. [PMID: 27861594 PMCID: PMC5115753 DOI: 10.1371/journal.pone.0166499] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 10/28/2016] [Indexed: 11/18/2022] Open
Abstract
The endoplasmic reticulum (ER) regulates organelle dynamics through the formation of membrane contact sites (MCS). Here we describe that VMP1, a multispanning ER-resident protein involved in autophagy, is enriched in ER micro-domains that are in close proximity to diverse organelles in HeLa and Cos-7 cells. These VMP1 puncta are highly dynamic, moving in concert with lipid droplets, mitochondria and endosomes. Some of these micro-domains are associated with ER sliding events and also with fission events of mitochondria and endosomes. VMP1-depleted cells display increased ER-mitochondria MCS and altered mitochondria morphology demonstrating a role in the regulation of MCS. Additional defects in ER structure and lipid droplets size and distribution are consistent with a more general function of VMP1 in membrane remodeling and organelle function. We hypothesize that in autophagy VMP1 is required for the correct morphogenesis of the omegasome by regulating MCS at the site of autophagosome formation.
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Affiliation(s)
- Luis-Carlos Tábara
- Instituto de Investigaciones Biomédicas Alberto Sols; C.S.I.C./U.A.M.; 28029-Madrid, Spain
| | - Ricardo Escalante
- Instituto de Investigaciones Biomédicas Alberto Sols; C.S.I.C./U.A.M.; 28029-Madrid, Spain
- * E-mail:
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Huang Y, Yang P, Liu T, Chen H, Chu X, Ahmad N, Zhang Q, Li Q, Hu L, Liu Y, Chen Q. Subcellular Evidence for Biogenesis of Autophagosomal Membrane during Spermiogenesis In vivo. Front Physiol 2016; 7:470. [PMID: 27803675 PMCID: PMC5067523 DOI: 10.3389/fphys.2016.00470] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 09/30/2016] [Indexed: 11/28/2022] Open
Abstract
Although autophagosome formation has attracted substantial attention, the origin and the source of the autophagosomal membrane remains unresolved. The present study was designed to investigate in vivo subcellular evidence for the biogenesis of autophagosomal membrane during spermiogenesis using transmission-electron microscopy (TEM), Western blots and immunohistochemistry in samples from the Chinese soft-shelled turtle. The testis expressed LC3-II protein, which was located within spermatids at different stages of differentiation and indicated active autophagy. TEM showed that numerous autophagosomes were developed inside spermatids. Many endoplasmic reticulum (ER) were transferred into a special “Chrysanthemum flower center” (CFC) in which several double-layer isolation membranes (IM) were formed and extended. The elongated IM always engulfed some cytoplasm and various structures. Narrow tubules connected the ends of multiple ER and the CFC. The CFC was more developed in spermatids with compact nuclei than in spermatids with granular nuclei. An IM could also be transformed from a single ER. Sometimes an IM extended from a trans-Golgi network and wrapped different structures. The plasma membrane of the spermatid invaginated to form vesicles that were distributed among various endosomes around the CFC during spermiogenesis. All this cellular evidence suggests that, in vivo, IM was developed mainly by CFC produced from ER within differentiating spermatids during spermiogenesis. Vesicles from Golgi complexes, plasma membranes and endosomes might also be the sources of the autophagosome membrane.
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Affiliation(s)
- Yufei Huang
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Ping Yang
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Tengfei Liu
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Hong Chen
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Xiaoya Chu
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Nisar Ahmad
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Qian Zhang
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Quanfu Li
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Lisi Hu
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Yi Liu
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Qiusheng Chen
- Laboratory of Animal Cell Biology and Embryology, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
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Petibone DM, Majeed W, Casciano DA. Autophagy function and its relationship to pathology, clinical applications, drug metabolism and toxicity. J Appl Toxicol 2016; 37:23-37. [PMID: 27682190 DOI: 10.1002/jat.3393] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 08/30/2016] [Accepted: 08/30/2016] [Indexed: 12/19/2022]
Abstract
Autophagy is a cellular process that facilitates nutrient turnover and removal of expended macromolecules and organelles to maintain homeostasis. The recycling of cytosolic macromolecules and damaged organelles by autophagosomes occurs through the lysosomal degradation pathway. Autophagy can also be upregulated as a prosurvival pathway in response to stress stimuli such as starvation, hypoxia or cell damage. Over the last two decades, there has been a surge in research revealing the basic molecular mechanisms of autophagy in mammalian cells. A corollary of an advanced understanding of autophagy has been a concurrent expansion of research into understanding autophagic function and dysfunction in pathology. Recent studies have revealed a pivotal role for autophagy in drug toxicity, and for utilizing autophagic components as diagnostic markers and therapeutic targets in treating disease and cancer. In this review, advances in understanding the molecular basis of mammalian autophagy, methods used to induce and evaluate autophagy, and the diverse interactions between autophagy and drug toxicity, disease progression and carcinogenesis are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Dayton M Petibone
- National Center for Toxicological Research, US FDA, Division of Genetic and Molecular Toxicology, Jefferson, AR, 72079, USA
| | - Waqar Majeed
- Center of Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
| | - Daniel A Casciano
- Center of Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, AR, 72204, USA
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Yang S, Rosenwald AG. Autophagy in Saccharomyces cerevisiae requires the monomeric GTP-binding proteins, Arl1 and Ypt6. Autophagy 2016; 12:1721-1737. [PMID: 27462928 PMCID: PMC5079543 DOI: 10.1080/15548627.2016.1196316] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Macroautophagy/autophagy is a cellular degradation process that sequesters organelles or proteins into a double-membrane structure called the phagophore; this transient compartment matures into an autophagosome, which then fuses with the lysosome or vacuole to allow hydrolysis of the cargo. Factors that control membrane traffic are also essential for each step of autophagy. Here we demonstrate that 2 monomeric GTP-binding proteins in Saccharomyces cerevisiae, Arl1 and Ypt6, which belong to the Arf/Arl/Sar protein family and the Rab family, respectively, and control endosome-trans-Golgi traffic, are also necessary for starvation-induced autophagy under high temperature stress. Using established autophagy-specific assays we found that cells lacking either ARL1 or YPT6, which exhibit synthetic lethality with one another, were unable to undergo autophagy at an elevated temperature, although autophagy proceeds normally at normal growth temperature; specifically, strains lacking one or the other of these genes are unable to construct the autophagosome because these 2 proteins are required for proper traffic of Atg9 to the phagophore assembly site (PAS) at the restrictive temperature. Using degron technology to construct an inducible arl1Δ ypt6Δ double mutant, we demonstrated that cells lacking both genes show defects in starvation-inducted autophagy at the permissive temperature. We also found Arl1 and Ypt6 participate in autophagy by targeting the Golgi-associated retrograde protein (GARP) complex to the PAS to regulate the anterograde trafficking of Atg9. Our data show that these 2 membrane traffic regulators have novel roles in autophagy.
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Affiliation(s)
- Shu Yang
- a Department of Biology , Georgetown University , Washington DC , USA
| | - Anne G Rosenwald
- a Department of Biology , Georgetown University , Washington DC , USA
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Fahie K, Zachara NE. Molecular Functions of Glycoconjugates in Autophagy. J Mol Biol 2016; 428:3305-3324. [PMID: 27345664 DOI: 10.1016/j.jmb.2016.06.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 05/27/2016] [Accepted: 06/16/2016] [Indexed: 02/07/2023]
Abstract
Glycoconjugates, glycans, carbohydrates, and sugars: these terms encompass a class of biomolecules that are diverse in both form and function ranging from free oligosaccharides, glycoproteins, and proteoglycans, to glycolipids that make up a complex glycan code that impacts normal physiology and disease. Recent data suggest that one mechanism by which glycoconjugates impact physiology is through the regulation of the process of autophagy. Autophagy is a degradative pathway necessary for differentiation, organism development, and the maintenance of cell and tissue homeostasis. In this review, we will highlight what is known about the regulation of autophagy by glycoconjugates focusing on signaling mechanisms from the extracellular surface and the regulatory roles of intracellular glycans. Glycan signaling from the extracellular matrix converges on "master" regulators of autophagy including AMPK and mTORC1, thus impacting their localization, activity, and/or expression. Within the intracellular milieu, gangliosides are constituents of the autophagosome membrane, a subset of proteins composing the autophagic machinery are regulated by glycosylation, and oligosaccharide exposure in the cytosol triggers an autophagic response. The examples discussed provide some mechanistic insights into glycan regulation of autophagy and reveal areas for future investigation.
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Affiliation(s)
- Kamau Fahie
- Department of Biological Chemistry, The Johns Hopkins University, School of Medicine, 725 N. Wolfe St, Baltimore, MD 21205-2185, USA
| | - Natasha E Zachara
- Department of Biological Chemistry, The Johns Hopkins University, School of Medicine, 725 N. Wolfe St, Baltimore, MD 21205-2185, USA.
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Turco E, Martens S. Insights into autophagosome biogenesis from in vitro reconstitutions. J Struct Biol 2016; 196:29-36. [PMID: 27251905 PMCID: PMC5039013 DOI: 10.1016/j.jsb.2016.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 01/01/2023]
Abstract
Macro-autophagy (autophagy) is a conserved catabolic pathway for the degradation of cytoplasmic material in the lysosomal system. This is achieved by the sequestration of the cytoplasmic cargo material within double membrane-bound vesicles that fuse with lysosomes, wherein the vesicle’s inner membrane and the cargo are degraded. Autophagosomes form in a de novo manner and their precursors are initially detected as small membrane structures that are referred to as isolation membranes. The isolation membranes gradually expand and subsequently close to give rise to autophagosomes. Many proteins required to form autophagosomes have been identified but how they act mechanistically is still enigmatic. Here we critically review reconstitution approaches employed to decipher the inner working of the fascinating autophagy machinery.
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Affiliation(s)
- Eleonora Turco
- Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
| | - Sascha Martens
- Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
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