1
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Kang N, Tan J, Yan S, Lin L, Gao Q. General autophagy-dependent and -independent lipophagic processes collaborate to regulate the overall level of lipophagy in yeast. Autophagy 2024; 20:1523-1536. [PMID: 38425021 PMCID: PMC11210923 DOI: 10.1080/15548627.2024.2325297] [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: 08/04/2023] [Accepted: 02/26/2024] [Indexed: 03/02/2024] Open
Abstract
ABBREVIATION AP: autophagosome; ATG: autophagy related; CMA: chaperone-mediated autophagy; ESCRT: endosomal sorting complex required for transport; FA: fatty acid; LD: lipid droplet; Ld microdomains: liquid-disordered microdomains; NL: neutral lipid.
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Affiliation(s)
- Na Kang
- School of Biomedical Sciences, Hunan University, Changsha, Hunan, China
| | - Jinling Tan
- School of Biomedical Sciences, Hunan University, Changsha, Hunan, China
| | - Sisi Yan
- School of Biomedical Sciences, Hunan University, Changsha, Hunan, China
| | - Leiying Lin
- School of Biomedical Sciences, Hunan University, Changsha, Hunan, China
| | - Qiang Gao
- Hunan Key Laboratory of Animal Models and Molecular Medicine, School of Biomedical Sciences, Hunan University, Changsha, Hunan, China
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2
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Isoda T, Takeda E, Hosokawa S, Hotta-Ren S, Ohsumi Y. Atg45 is an autophagy receptor for glycogen, a non-preferred cargo of bulk autophagy in yeast. iScience 2024; 27:109810. [PMID: 38832010 PMCID: PMC11145338 DOI: 10.1016/j.isci.2024.109810] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/03/2023] [Accepted: 04/22/2024] [Indexed: 06/05/2024] Open
Abstract
The mechanisms governing autophagy of proteins and organelles have been well studied, but how other cytoplasmic components such as RNA and polysaccharides are degraded remains largely unknown. In this study, we examine autophagy of glycogen, a storage form of glucose. We find that cells accumulate glycogen in the cytoplasm during nitrogen starvation and that this carbohydrate is rarely observed within autophagosomes and autophagic bodies. However, sequestration of glycogen by autophagy is observed following prolonged nitrogen starvation. We identify a yet-uncharacterized open reading frame, Yil024c (herein Atg45), as encoding a cytosolic receptor protein that mediates autophagy of glycogen (glycophagy). Furthermore, we show that, during sporulation, Atg45 is highly expressed and is associated with an increase in glycophagy. Our results suggest that cells regulate glycophagic activity by controlling the expression level of Atg45.
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Affiliation(s)
- Takahiro Isoda
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- School and Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- Frontier Research Center, POLA Chemical Industries, Inc, Yokohama 244-0812, Japan
| | - Eigo Takeda
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Sachiko Hosokawa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Shukun Hotta-Ren
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Yoshinori Ohsumi
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
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3
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Soong TH, Hotze C, Khandelwal NK, Tomasiak TM. Structural Basis for Oxidized Glutathione Recognition by the Yeast Cadmium Factor 1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.578287. [PMID: 38352558 PMCID: PMC10862839 DOI: 10.1101/2024.01.31.578287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Transporters from the ABCC family have an essential role in detoxifying electrophilic compounds including metals, drugs, and lipids, often through conjugation with glutathione complexes. The Yeast Cadmium Factor 1 (Ycf1) transports glutathione alone as well as glutathione conjugated to toxic heavy metals including Cd2+, Hg2+, and As3+. To understand the complicated selectivity and promiscuity of heavy metal substrate binding, we determined the cryo-EM structure of Ycf1 bound to the substrate, oxidized glutathione. We systematically tested binding determinants with cellular survival assays against cadmium to determine how the substrate site accommodates different-sized metal complexes. We identify a "flex-pocket" for substrate binding that binds glutathione complexes asymmetrically and flexes to accommodate different size complexes.
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Affiliation(s)
- Tik Hang Soong
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Clare Hotze
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Nitesh Kumar Khandelwal
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Department of Biochemistry and Physics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Thomas M Tomasiak
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
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4
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Kagohashi Y, Sasaki M, May AI, Kawamata T, Ohsumi Y. The mechanism of Atg15-mediated membrane disruption in autophagy. J Cell Biol 2023; 222:e202306120. [PMID: 37917025 PMCID: PMC10622257 DOI: 10.1083/jcb.202306120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/25/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023] Open
Abstract
Autophagy is a lysosomal/vacuolar delivery system that degrades cytoplasmic material. During autophagy, autophagosomes deliver cellular components to the vacuole, resulting in the release of a cargo-containing autophagic body (AB) into the vacuole. AB membranes must be disrupted for degradation of cargo to occur. The lipase Atg15 and vacuolar proteases Pep4 and Prb1 are known to be necessary for this disruption and cargo degradation, but the mechanistic underpinnings remain unclear. In this study, we establish a system to detect lipase activity in the vacuole and show that Atg15 is the sole vacuolar phospholipase. Pep4 and Prb1 are required for the activation of Atg15 lipase function, which occurs following delivery of Atg15 to the vacuole by the MVB pathway. In vitro experiments reveal that Atg15 is a phospholipase B of broad substrate specificity that is likely implicated in the disruption of a range of membranes. Further, we use isolated ABs to demonstrate that Atg15 alone is able to disrupt AB membranes.
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Affiliation(s)
- Yoko Kagohashi
- Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- POLA Chemical Industries, Inc., Yokohama, Japan
| | - Michiko Sasaki
- Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Alexander I. May
- Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Tomoko Kawamata
- Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Yoshinori Ohsumi
- Research Center for Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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5
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Elander PH, Holla S, Sabljić I, Gutierrez-Beltran E, Willems P, Bozhkov PV, Minina EA. Interactome of Arabidopsis ATG5 Suggests Functions beyond Autophagy. Int J Mol Sci 2023; 24:12300. [PMID: 37569688 PMCID: PMC10418956 DOI: 10.3390/ijms241512300] [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: 07/05/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/13/2023] Open
Abstract
Autophagy is a catabolic pathway capable of degrading cellular components ranging from individual molecules to organelles. Autophagy helps cells cope with stress by removing superfluous or hazardous material. In a previous work, we demonstrated that transcriptional upregulation of two autophagy-related genes, ATG5 and ATG7, in Arabidopsis thaliana positively affected agronomically important traits: biomass, seed yield, tolerance to pathogens and oxidative stress. Although the occurrence of these traits correlated with enhanced autophagic activity, it is possible that autophagy-independent roles of ATG5 and ATG7 also contributed to the phenotypes. In this study, we employed affinity purification and LC-MS/MS to identify the interactome of wild-type ATG5 and its autophagy-inactive substitution mutant, ATG5K128R Here we present the first interactome of plant ATG5, encompassing not only known autophagy regulators but also stress-response factors, components of the ubiquitin-proteasome system, proteins involved in endomembrane trafficking, and potential partners of the nuclear fraction of ATG5. Furthermore, we discovered post-translational modifications, such as phosphorylation and acetylation present on ATG5 complex components that are likely to play regulatory functions. These results strongly indicate that plant ATG5 complex proteins have roles beyond autophagy itself, opening avenues for further investigations on the complex roles of autophagy in plant growth and stress responses.
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Affiliation(s)
- Pernilla H. Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Sanjana Holla
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Igor Sabljić
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Emilio Gutierrez-Beltran
- Instituto de Bioquımica Vegetal y Fotosıntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Cientıficas, 41092 Sevilla, Spain;
- Departamento de Bioquimica Vegetal y Biologia Molecular, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Patrick Willems
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium;
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
| | - Peter V. Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
| | - Elena A. Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750-07 Uppsala, Sweden; (P.H.E.); (S.H.); (I.S.); (P.V.B.)
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6
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Stasic AJ, Moreno SNJ, Carruthers VB, Dou Z. The Toxoplasma plant-like vacuolar compartment (PLVAC). J Eukaryot Microbiol 2022; 69:e12951. [PMID: 36218001 PMCID: PMC10576567 DOI: 10.1111/jeu.12951] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/06/2022] [Accepted: 10/07/2022] [Indexed: 11/28/2022]
Abstract
Toxoplasma gondii belongs to the phylum Apicomplexa and is an important cause of congenital disease and infection in immunocompromised patients. T. gondii shares several characteristics with plants including a nonphotosynthetic plastid termed apicoplast and a multivesicular organelle that was named the plant-like vacuole (PLV) or vacuolar compartment (VAC). The name plant-like vacuole was selected based on its resemblance in composition and function to plant vacuoles. The name VAC represents its general vacuolar characteristics. We will refer to the organelle as PLVAC in this review. New findings in recent years have revealed that the PLVAC represents the lysosomal compartment of T. gondii which has adapted peculiarities to fulfill specific Toxoplasma needs. In this review, we discuss the composition and functions of the PLVAC highlighting its roles in ion storage and homeostasis, endocytosis, exocytosis, and autophagy.
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Affiliation(s)
- Andrew J Stasic
- Department of Microbiology, Heartland FPG, Carmel, Indiana, USA
| | - Silvia N J Moreno
- Department of Cellular Biology, University of Georgia, Georgia, Athens, USA
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Georgia, Athens, USA
| | - Vern B Carruthers
- Department of Microbiology & Immunology, University of Michigan Medical School, Michigan, Ann Arbor, USA
| | - Zhicheng Dou
- Department of Biological Sciences, Clemson University, South Carolina, Clemson, USA
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7
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Juárez-Montiel M, Clark-Flores D, Tesillo-Moreno P, de la Vega-Camarillo E, Andrade-Pavón D, Hernández-García JA, Hernández-Rodríguez C, Villa-Tanaca L. Vacuolar proteases and autophagy in phytopathogenic fungi: A review. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:948477. [PMID: 37746183 PMCID: PMC10512327 DOI: 10.3389/ffunb.2022.948477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 10/11/2022] [Indexed: 09/26/2023]
Abstract
Autophagy (macroautophagy) is a survival and virulence mechanism of different eukaryotic pathogens. Autophagosomes sequester cytosolic material and organelles, then fuse with or enter into the vacuole or lysosome (the lytic compartment of most fungal/plant cells and many animal cells, respectively). Subsequent degradation of cargoes delivered to the vacuole via autophagy and endocytosis maintains cellular homeostasis and survival in conditions of stress, cellular differentiation, and development. PrA and PrB are vacuolar aspartyl and serine endoproteases, respectively, that participate in the autophagy of fungi and contribute to the pathogenicity of phytopathogens. Whereas the levels of vacuolar proteases are regulated by the expression of the genes encoding them (e.g., PEP4 for PrA and PRB1 for PrB), their activity is governed by endogenous inhibitors. The aim of the current contribution is to review the main characteristics, regulation, and role of vacuolar soluble endoproteases and Atg proteins in the process of autophagy and the pathogenesis of three fungal phytopathogens: Ustilago maydis, Magnaporthe oryzae, and Alternaria alternata. Aspartyl and serine proteases are known to participate in autophagy in these fungi by degrading autophagic bodies. However, the gene responsible for encoding the vacuolar serine protease of U. maydis has yet to be identified. Based on in silico analysis, this U. maydis gene is proposed to be orthologous to the Saccharomyces cerevisiae genes PRB1 and PBI2, known to encode the principal protease involved in the degradation of autophagic bodies and its inhibitor, respectively. In fungi that interact with plants, whether phytopathogenic or mycorrhizal, autophagy is a conserved cellular degradation process regulated through the TOR, PKA, and SNF1 pathways by ATG proteins and vacuolar proteases. Autophagy plays a preponderant role in the recycling of cell components as well as in the fungus-plant interaction.
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Affiliation(s)
| | | | | | | | | | | | | | - Lourdes Villa-Tanaca
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Mexico City, Mexico
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8
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Application of Metabolomics in the Study of Starvation-Induced Autophagy in Saccharomyces cerevisiae: A Scoping Review. J Fungi (Basel) 2021; 7:jof7110987. [PMID: 34829274 PMCID: PMC8619235 DOI: 10.3390/jof7110987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 11/18/2022] Open
Abstract
This scoping review is aimed at the application of the metabolomics platform to dissect key metabolites and their intermediates to observe the regulatory mechanisms of starvation-induced autophagy in Saccharomyces cerevisiae. Four research papers were shortlisted in this review following the inclusion and exclusion criteria. We observed a commonly shared pathway undertaken by S. cerevisiae under nutritional stress. Targeted and untargeted metabolomics was applied in either of these studies using varying platforms resulting in the annotation of several different observable metabolites. We saw a commonly shared pathway undertaken by S. cerevisiae under nutritional stress. Following nitrogen starvation, the concentration of cellular nucleosides was altered as a result of autophagic RNA degradation. Additionally, it is also found that autophagy replenishes amino acid pools to sustain macromolecule synthesis. Furthermore, in glucose starvation, nucleosides were broken down into carbonaceous metabolites that are being funneled into the non-oxidative pentose phosphate pathway. The ribose salvage allows for the survival of starved yeast. Moreover, acute glucose starvation showed autophagy to be involved in maintaining ATP/energy levels. We highlighted the practicality of metabolomics as a tool to better understand the underlying mechanisms involved to maintain homeostasis by recycling degradative products to ensure the survival of S. cerevisiae under starvation. The application of metabolomics has extended the scope of autophagy and provided newer intervention targets against cancer as well as neurodegenerative diseases in which autophagy is implicated.
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9
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Ebrahimi M, Habernig L, Broeskamp F, Aufschnaiter A, Diessl J, Atienza I, Matz S, Ruiz FA, Büttner S. Phosphate Restriction Promotes Longevity via Activation of Autophagy and the Multivesicular Body Pathway. Cells 2021; 10:3161. [PMID: 34831384 PMCID: PMC8620443 DOI: 10.3390/cells10113161] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 01/05/2023] Open
Abstract
Nutrient limitation results in an activation of autophagy in organisms ranging from yeast, nematodes and flies to mammals. Several evolutionary conserved nutrient-sensing kinases are critical for efficient adaptation of yeast cells to glucose, nitrogen or phosphate depletion, subsequent cell-cycle exit and the regulation of autophagy. Here, we demonstrate that phosphate restriction results in a prominent extension of yeast lifespan that requires the coordinated activity of autophagy and the multivesicular body pathway, enabling efficient turnover of cytoplasmic and plasma membrane cargo. While the multivesicular body pathway was essential during the early days of aging, autophagy contributed to long-term survival at later days. The cyclin-dependent kinase Pho85 was critical for phosphate restriction-induced autophagy and full lifespan extension. In contrast, when cell-cycle exit was triggered by exhaustion of glucose instead of phosphate, Pho85 and its cyclin, Pho80, functioned as negative regulators of autophagy and lifespan. The storage of phosphate in form of polyphosphate was completely dispensable to in sustaining viability under phosphate restriction. Collectively, our results identify the multifunctional, nutrient-sensing kinase Pho85 as critical modulator of longevity that differentially coordinates the autophagic response to distinct kinds of starvation.
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Affiliation(s)
- Mahsa Ebrahimi
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Filomena Broeskamp
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Andreas Aufschnaiter
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden;
| | - Jutta Diessl
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Isabel Atienza
- Instituto de Investigación e Innovación Biomédica de Cádiz (INIBICA), University of Cadiz, 11001 Cadiz, Spain; (I.A.); (F.A.R.)
| | - Steffen Matz
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
| | - Felix A. Ruiz
- Instituto de Investigación e Innovación Biomédica de Cádiz (INIBICA), University of Cadiz, 11001 Cadiz, Spain; (I.A.); (F.A.R.)
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; (M.E.); (L.H.); (F.B.); (J.D.); (S.M.)
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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10
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Miyazaki M, Hiramoto M, Takano N, Kokuba H, Takemura J, Tokuhisa M, Hino H, Kazama H, Miyazawa K. Targeted disruption of GAK stagnates autophagic flux by disturbing lysosomal dynamics. Int J Mol Med 2021; 48:195. [PMID: 34468012 PMCID: PMC8416139 DOI: 10.3892/ijmm.2021.5028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/05/2021] [Indexed: 01/13/2023] Open
Abstract
The autophagy-lysosome system allows cells to adapt to environmental changes by regulating the degradation and recycling of cellular components, and to maintain homeostasis by removing aggregated proteins and defective organelles. Cyclin G-associated kinase (GAK) is involved in the regulation of clathrin-dependent endocytosis and cell cycle progression. In addition, a single nucleotide polymorphism at the GAK locus has been reported as a risk factor for Parkinson's disease. However, the roles of GAK in the autophagy-lysosome system are not completely understood, thus the present study aimed to clarify this. In the present study, under genetic disruption or chemical inhibition of GAK, analyzing autophagic flux and observing morphological changes of autophagosomes and autolysosomes revealed that GAK controlled lysosomal dynamics via actomyosin regulation, resulting in a steady progression of autophagy. GAK knockout (KO) in A549 cells impaired autophagosome-lysosome fusion and autophagic lysosome reformation, which resulted in the accumulation of enlarged autophagosomes and autolysosomes during prolonged starvation. The stagnation of autophagic flux accompanied by these phenomena was also observed with the addition of a GAK inhibitor. Furthermore, the addition of Rho-associated protein kinase (ROCK) inhibitor or ROCK1 knockdown mitigated GAK KO-mediated effects. The results suggested a vital role of GAK in controlling lysosomal dynamics via maintaining lysosomal homeostasis during autophagy.
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Affiliation(s)
- Masaya Miyazaki
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Masaki Hiramoto
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Naoharu Takano
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Hiroko Kokuba
- Laboratory of Electron Microscopy, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Jun Takemura
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Mayumi Tokuhisa
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Hirotsugu Hino
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Hiromi Kazama
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
| | - Keisuke Miyazawa
- Department of Biochemistry, Tokyo Medical University, Tokyo 160‑8402, Japan
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11
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Fan Y, Shao J, Wei S, Song C, Li Y, Jiang S. Self-eating and Heart: The Emerging Roles of Autophagy in Calcific Aortic Valve Disease. Aging Dis 2021; 12:1287-1303. [PMID: 34341709 PMCID: PMC8279526 DOI: 10.14336/ad.2021.0101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 01/01/2021] [Indexed: 12/16/2022] Open
Abstract
Autophagy is a self-degradative pathway by which subcellular elements are broken down intracellularly to maintain cellular homeostasis. Cardiac autophagy commonly decreases with aging and is accompanied by the accumulation of misfolded proteins and dysfunctional organelles, which are undesirable to the cell. Reduction of autophagy over time leads to aging-related cardiac dysfunction and is inversely related to longevity. However, despite the increasing interest in autophagy in cardiac diseases and aging, the process remains an undervalued and disregarded object in calcific valvular disease. Neither the nature through which autophagy is triggered nor the interplay between autophagic machinery and targeted molecules during aortic valve calcification are fully understood. Recently, the upregulation of autophagy has been shown to result in cardioprotective effects against cell death as well as its origin. Here, we review the evidence that shows how autophagy can be both beneficial and detrimental as it pertains to aortic valve calcification in the heart.
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Affiliation(s)
- Yunlong Fan
- 1Medical School of Chinese PLA, Beijing 100853, China.,2Department of Cardiovascular Surgery, the First Medical Centre of Chinese PLA General Hospital, Beijing 100853, China
| | - Jiakang Shao
- 1Medical School of Chinese PLA, Beijing 100853, China
| | - Shixiong Wei
- 1Medical School of Chinese PLA, Beijing 100853, China.,2Department of Cardiovascular Surgery, the First Medical Centre of Chinese PLA General Hospital, Beijing 100853, China
| | - Chao Song
- 1Medical School of Chinese PLA, Beijing 100853, China.,2Department of Cardiovascular Surgery, the First Medical Centre of Chinese PLA General Hospital, Beijing 100853, China
| | - Yanan Li
- 1Medical School of Chinese PLA, Beijing 100853, China
| | - Shengli Jiang
- 1Medical School of Chinese PLA, Beijing 100853, China.,2Department of Cardiovascular Surgery, the First Medical Centre of Chinese PLA General Hospital, Beijing 100853, China
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12
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Huang YJ, Klionsky DJ. Yeast mitophagy: Unanswered questions. Biochim Biophys Acta Gen Subj 2021; 1865:129932. [PMID: 34022298 PMCID: PMC8205991 DOI: 10.1016/j.bbagen.2021.129932] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 01/18/2023]
Abstract
Superfluous and damaged mitochondria need to be efficiently repaired or removed. Mitophagy is a selective type of autophagy that can engulf a portion of mitochondria within a double-membrane structure, called a mitophagosome, and deliver it to the vacuole for degradation. Mitophagy has significant physiological functions from yeast to human, and recent advances in yeast mitophagy shed light on the molecular mechanisms of mitophagy, especially the regulation of mitophagy induction. This review summarizes our current knowledge about yeast mitophagy and considers several unsolved questions, with a particular focus on Saccharomyces cerevisiae.
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Affiliation(s)
- Yuxiang J Huang
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Daniel J Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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13
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Lemus L, Matić Z, Gal L, Fadel A, Schuldiner M, Goder V. Post-ER degradation of misfolded GPI-anchored proteins is linked with microautophagy. Curr Biol 2021; 31:4025-4037.e5. [PMID: 34314677 DOI: 10.1016/j.cub.2021.06.078] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/07/2021] [Accepted: 06/25/2021] [Indexed: 01/08/2023]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are membrane-conjugated cell-surface proteins with diverse structural, developmental, and signaling functions and clinical relevance. Typically, after biosynthesis and attachment to the preassembled GPI anchor, GPI-APs rapidly leave the endoplasmic reticulum (ER) and rely on post-ER quality control. Terminally misfolded GPI-APs end up inside the vacuole/lysosome for degradation, but their trafficking itinerary to this organelle and the processes linked to their uptake by the vacuole/lysosome remain uncharacterized. In a yeast mutant that is lacking Pep4, a key vacuolar protease, several misfolded model GPI-APs accumulated in the vacuolar membrane. In the same mutant, macroautophagy and the multi-vesicular body (MVB) pathway were intact, hinting at a hitherto-unknown trafficking pathway for the degradation of misfolded GPI-APs. To unravel it, we used a genome-wide screen coupled to high-throughput fluorescence microscopy and followed the fate of the misfolded GPI-AP: Gas1∗. We found that components of the early secretory and endocytic pathways are involved in its targeting to the vacuole and that vacuolar transporter chaperones (VTCs), with roles in microautophagy, negatively affect the vacuolar uptake of Gas1∗. In support, we demonstrate that Gas1∗ internalizes from vacuolar membranes into membrane-bound intravacuolar vesicles prior to degradation. Our data link post-ER degradation with microautophagy.
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Affiliation(s)
- Leticia Lemus
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
| | - Zrinka Matić
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain
| | - Lihi Gal
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Amir Fadel
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Veit Goder
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
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14
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Tomashevsky A, Kulakovskaya E, Trilisenko L, Kulakovskiy IV, Kulakovskaya T, Fedorov A, Eldarov M. VTC4 Polyphosphate Polymerase Knockout Increases Stress Resistance of Saccharomyces cerevisiae Cells. BIOLOGY 2021; 10:487. [PMID: 34070801 PMCID: PMC8227513 DOI: 10.3390/biology10060487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 11/17/2022]
Abstract
Inorganic polyphosphate (polyP) is an important factor of alkaline, heavy metal, and oxidative stress resistance in microbial cells. In yeast, polyP is synthesized by Vtc4, a subunit of the vacuole transporter chaperone complex. Here, we report reduced but reliably detectable amounts of acid-soluble and acid-insoluble polyPs in the Δvtc4 strain of Saccharomyces cerevisiae, reaching 10% and 20% of the respective levels of the wild-type strain. The Δvtc4 strain has decreased resistance to alkaline stress but, unexpectedly, increased resistance to oxidation and heavy metal excess. We suggest that increased resistance is achieved through elevated expression of DDR2, which is implicated in stress response, and reduced expression of PHO84 encoding a phosphate and divalent metal transporter. The decreased Mg2+-dependent phosphate accumulation in Δvtc4 cells is consistent with reduced expression of PHO84. We discuss a possible role that polyP level plays in cellular signaling of stress response mobilization in yeast.
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Affiliation(s)
- Alexander Tomashevsky
- Federal Scientific Center, Pushchino Research Center for Biology of the Russian Academy of Sciences, Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, pr. Nauki 5, 142290 Pushchino, Russia; (A.T.); (E.K.); (L.T.)
| | - Ekaterina Kulakovskaya
- Federal Scientific Center, Pushchino Research Center for Biology of the Russian Academy of Sciences, Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, pr. Nauki 5, 142290 Pushchino, Russia; (A.T.); (E.K.); (L.T.)
| | - Ludmila Trilisenko
- Federal Scientific Center, Pushchino Research Center for Biology of the Russian Academy of Sciences, Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, pr. Nauki 5, 142290 Pushchino, Russia; (A.T.); (E.K.); (L.T.)
| | - Ivan V. Kulakovskiy
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia;
- Vavilov Institute of General Genetics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Tatiana Kulakovskaya
- Federal Scientific Center, Pushchino Research Center for Biology of the Russian Academy of Sciences, Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, pr. Nauki 5, 142290 Pushchino, Russia; (A.T.); (E.K.); (L.T.)
| | - Alexey Fedorov
- Federal Scientific Center for Biotechnology of the Russian Academy of Sciences, Institute of Bioengineering, Russian Academy of Sciences, Leninsky prosp. 33-2, 119071 Moscow, Russia; (A.F.); (M.E.)
| | - Mikhail Eldarov
- Federal Scientific Center for Biotechnology of the Russian Academy of Sciences, Institute of Bioengineering, Russian Academy of Sciences, Leninsky prosp. 33-2, 119071 Moscow, Russia; (A.F.); (M.E.)
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15
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Di YQ, Han XL, Kang XL, Wang D, Chen CH, Wang JX, Zhao XF. Autophagy triggers CTSD (cathepsin D) maturation and localization inside cells to promote apoptosis. Autophagy 2021; 17:1170-1192. [PMID: 32324083 PMCID: PMC8143247 DOI: 10.1080/15548627.2020.1752497] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 03/30/2020] [Accepted: 04/02/2020] [Indexed: 12/28/2022] Open
Abstract
CTSD/CathD/CATD (cathepsin D) is a lysosomal aspartic protease. A distinguishing characteristic of CTSD is its dual functions of promoting cell proliferation via secreting a pro-enzyme outside the cells as a ligand, and promoting apoptosis via the mature form of this enzyme inside cells; however, the regulation of its secretion, expression, and maturation is undetermined. Using the lepidopteran insect Helicoverpa armigera, a serious agricultural pest, as a model, we revealed the dual functions and regulatory mechanisms of CTSD secretion, expression, and maturation. Glycosylation of asparagine 233 (N233) determined pro-CTSD secretion. The steroid hormone 20-hydroxyecdysone (20E) promoted CTSD expression. Macroautophagy/autophagy triggered CTSD maturation and localization inside midgut cells to activate CASP3 (caspase 3) and promote apoptosis. Pro-CTSD was expressed in the pupal epidermis and was secreted into the hemolymph to promote adult fat body endoreplication/endoreduplication, cell proliferation, and association. Our study revealed that the differential expression and autophagy-mediated maturation of CTSD in tissues determine its roles in apoptosis and cell proliferation, thereby determining the cell fates of tissues during lepidopteran metamorphosis.Abbreviations: 20E: 20-hydroxyecdysone; 3-MA: 3-methyladenine; ACTB/β-actin: actin beta; AKT: protein kinase B; ATG1: autophagy-related 1; ATG4: autophagy-related 4; ATG5: autophagy-related 5; ATG7: autophagy-related 7; ATG14: autophagy-related 14; BSA: bovine serum albumin; CASP3: caspase 3; CQ: choroquine; CTSD: cathepsin D; DAPI: 4',6-diamidino-2-phenylindole; DMSO: dimethyl sulfoxide; DPBS: dulbecco's phosphate-buffered saline; DsRNA: double-stranded RNA; EcR: ecdysone receptor; EcRE: ecdysone response element; EdU: 5-ethynyl-2´-deoxyuridine; G-m-CTSD: glycosylated-mautre-CTSD; G-pro-CTSD: glycosylated-pro-CTSD; HaEpi: Helicoverpa armigera epidermal cell line; HE staining: hematoxylin and eosin staining; IgG: immunoglobin G; IM: imaginal midgut; JH: juvenile hormone; Kr-h1: krueppel homologous protein 1; LM: larval midgut; M6P: mannose-6-phosphate; PBS: phosphate-buffered saline; PCD: programmed cell death; PNGase: peptide-N-glycosidase F; RFP: red fluorescent protein; RNAi: RNA interference; SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; SYX17: syntaxin 17; USP1: ultraspiracle isoform 1.
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Affiliation(s)
- Yu-Qin Di
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xiao-Lin Han
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xin-Le Kang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Di Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Cai-Hua Chen
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Jin-Xing Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xiao-Fan Zhao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
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16
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Robichaud S, Fairman G, Vijithakumar V, Mak E, Cook DP, Pelletier AR, Huard S, Vanderhyden BC, Figeys D, Lavallée-Adam M, Baetz K, Ouimet M. Identification of novel lipid droplet factors that regulate lipophagy and cholesterol efflux in macrophage foam cells. Autophagy 2021; 17:3671-3689. [PMID: 33590792 PMCID: PMC8632324 DOI: 10.1080/15548627.2021.1886839] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Macrophage autophagy is a highly anti-atherogenic process that promotes the catabolism of cytosolic lipid droplets (LDs) to maintain cellular lipid homeostasis. Selective autophagy relies on tags such as ubiquitin and a set of selectivity factors including selective autophagy receptors (SARs) to label specific cargo for degradation. Originally described in yeast cells, "lipophagy" refers to the degradation of LDs by autophagy. Yet, how LDs are targeted for autophagy is poorly defined. Here, we employed mass spectrometry to identify lipophagy factors within the macrophage foam cell LD proteome. In addition to structural proteins (e.g., PLIN2), metabolic enzymes (e.g., ACSL) and neutral lipases (e.g., PNPLA2), we found the association of proteins related to the ubiquitination machinery (e.g., AUP1) and autophagy (e.g., HMGB, YWHA/14-3-3 proteins). The functional role of candidate lipophagy factors (a total of 91) was tested using a custom siRNA array combined with high-content cholesterol efflux assays. We observed that knocking down several of these genes, including Hmgb1, Hmgb2, Hspa5, and Scarb2, significantly reduced cholesterol efflux, and SARs SQSTM1/p62, NBR1 and OPTN localized to LDs, suggesting a role for these in lipophagy. Using yeast lipophagy assays, we established a genetic requirement for several candidate lipophagy factors in lipophagy, including HSPA5, UBE2G2 and AUP1. Our study is the first to systematically identify several LD-associated proteins of the lipophagy machinery, a finding with important biological and therapeutic implications. Targeting these to selectively enhance lipophagy to promote cholesterol efflux in foam cells may represent a novel strategy to treat atherosclerosis.Abbreviations:ADGRL3: adhesion G protein-coupled receptor L3; agLDL: aggregated low density lipoprotein; AMPK: AMP-activated protein kinase; APOA1: apolipoprotein A1; ATG: autophagy related; AUP1: AUP1 lipid droplet regulating VLDL assembly factor; BMDM: bone-marrow derived macrophages; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; BSA: bovine serum albumin; CALCOCO2: calcium binding and coiled-coil domain 2; CIRBP: cold inducible RNA binding protein; COLGALT1: collagen beta(1-O)galactosyltransferase 1; CORO1A: coronin 1A; DMA: deletion mutant array; Faa4: long chain fatty acyl-CoA synthetase; FBS: fetal bovine serum; FUS: fused in sarcoma; HMGB1: high mobility group box 1; HMGB2: high mobility group box 2: HSP90AA1: heat shock protein 90: alpha (cytosolic): class A member 1; HSPA5: heat shock protein family A (Hsp70) member 5; HSPA8: heat shock protein 8; HSPB1: heat shock protein 1; HSPH1: heat shock 105kDa/110kDa protein 1; LDAH: lipid droplet associated hydrolase; LIPA: lysosomal acid lipase A; LIR: LC3-interacting region; MACROH2A1: macroH2A.1 histone; MAP1LC3: microtubule-associated protein 1 light chain 3; MCOLN1: mucolipin 1; NBR1: NBR1, autophagy cargo receptor; NPC2: NPC intracellular cholesterol transporter 2; OPTN: optineurin; P/S: penicillin-streptomycin; PLIN2: perilipin 2; PLIN3: perilipin 3; PNPLA2: patatin like phospholipase domain containing 2; RAB: RAB, member RAS oncogene family; RBBP7, retinoblastoma binding protein 7, chromatin remodeling factor; SAR: selective autophagy receptor; SCARB2: scavenger receptor class B, member 2; SGA: synthetic genetic array; SQSTM1: sequestosome 1; TAX1BP1: Tax1 (human T cell leukemia virus type I) binding protein 1; TFEB: transcription factor EB; TOLLIP: toll interacting protein; UBE2G2: ubiquitin conjugating enzyme E2 G2; UVRAG: UV radiation resistance associated gene; VDAC2: voltage dependent anion channel 2; VIM: vimentin.
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Affiliation(s)
- Sabrina Robichaud
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Garrett Fairman
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Viyashini Vijithakumar
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Esther Mak
- University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - David P Cook
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Alexander R Pelletier
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Ottawa Institute of Systems Biology, Ottawa, ON, Canada
| | - Sylvain Huard
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Ottawa Institute of Systems Biology, Ottawa, ON, Canada
| | - Barbara C Vanderhyden
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Daniel Figeys
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Ottawa Institute of Systems Biology, Ottawa, ON, Canada
| | - Mathieu Lavallée-Adam
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Ottawa Institute of Systems Biology, Ottawa, ON, Canada
| | - Kristin Baetz
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Ottawa Institute of Systems Biology, Ottawa, ON, Canada
| | - Mireille Ouimet
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Heart Institute, Ottawa, ON, Canada
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17
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Abstract
The 26S proteasome is the most complex ATP-dependent protease machinery, of ~2.5 MDa mass, ubiquitously found in all eukaryotes. It selectively degrades ubiquitin-conjugated proteins and plays fundamentally indispensable roles in regulating almost all major aspects of cellular activities. To serve as the sole terminal "processor" for myriad ubiquitylation pathways, the proteasome evolved exceptional adaptability in dynamically organizing a large network of proteins, including ubiquitin receptors, shuttle factors, deubiquitinases, AAA-ATPase unfoldases, and ubiquitin ligases, to enable substrate selectivity and processing efficiency and to achieve regulation precision of a vast diversity of substrates. The inner working of the 26S proteasome is among the most sophisticated, enigmatic mechanisms of enzyme machinery in eukaryotic cells. Recent breakthroughs in three-dimensional atomic-level visualization of the 26S proteasome dynamics during polyubiquitylated substrate degradation elucidated an extensively detailed picture of its functional mechanisms, owing to progressive methodological advances associated with cryogenic electron microscopy (cryo-EM). Multiple sites of ubiquitin binding in the proteasome revealed a canonical mode of ubiquitin-dependent substrate engagement. The proteasome conformation in the act of substrate deubiquitylation provided insights into how the deubiquitylating activity of RPN11 is enhanced in the holoenzyme and is coupled to substrate translocation. Intriguingly, three principal modes of coordinated ATP hydrolysis in the heterohexameric AAA-ATPase motor were discovered to regulate intermediate functional steps of the proteasome, including ubiquitin-substrate engagement, deubiquitylation, initiation of substrate translocation and processive substrate degradation. The atomic dissection of the innermost working of the 26S proteasome opens up a new era in our understanding of the ubiquitin-proteasome system and has far-reaching implications in health and disease.
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Affiliation(s)
- Youdong Mao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, 02215, Massachusetts, USA. .,School of Physics, Center for Quantitative Biology, Peking University, Beijing, 100871, China.
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18
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Autophagy sustains glutamate and aspartate synthesis in Saccharomyces cerevisiae during nitrogen starvation. Nat Commun 2021; 12:57. [PMID: 33397945 PMCID: PMC7782722 DOI: 10.1038/s41467-020-20253-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/20/2020] [Indexed: 01/29/2023] Open
Abstract
Autophagy catabolizes cellular constituents to promote survival during nutrient deprivation. Yet, a metabolic comprehension of this recycling operation, despite its crucial importance, remains incomplete. Here, we uncover a specific metabolic function of autophagy that exquisitely adjusts cellular metabolism according to nitrogen availability in the budding yeast Saccharomyces cerevisiae. Autophagy enables metabolic plasticity to promote glutamate and aspartate synthesis, which empowers nitrogen-starved cells to replenish their nitrogen currency and sustain macromolecule synthesis. Our findings provide critical insights into the metabolic basis by which autophagy recycles cellular components and may also have important implications in understanding the role of autophagy in diseases such as cancer.
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19
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Niu R, Wang J, Geng C, Li Y, Dong L, Liu L, Chang Y, Shen J, Nie Z, Zhang Y, Hu B. Tandem mass tag-based proteomic analysis reveals cathepsin-mediated anti-autophagic and pro-apoptotic effects under proliferative diabetic retinopathy. Aging (Albany NY) 2020; 13:973-990. [PMID: 33293479 PMCID: PMC7835038 DOI: 10.18632/aging.202217] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 10/08/2020] [Indexed: 04/20/2023]
Abstract
Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes and can cause blindness. However, the available therapeutic modalities to PDR have unsatisfactory efficacies and incur adverse effects, which is due to the paucity in the understanding of pathogenic mechanisms responsible for the disease. In this study, tandem mass tag labeling technology combined with liquid chromatography and tandem mass spectrometry were utilized to identify differentially expressed proteins in vitreous humor of patients with rhegmatogenous retinal detachment and PDR. The data are available via ProteomeXchange with identifier PXD021788. Afterwards, the downregulated protein expression of Cathepsin B, D, and L was verified in vitreous and serum of another cohort. The gene expression profiling of the 3 cathepsins was confirmed in blood cells of an extra cohort. Furthermore, in high glucose (HG)-treated retinal vascular endothelial cell cultures recapitulating the cathepsin expression patterns, Cathepsin B or D downregulation mediated the HG-induced anti-autophagic and pro-apoptotic effects, thereby may contribute to vascular lesions under hyperglycemia. This study demonstrates previously undescribed expression patterns of cathepsins, reveals a novel cathepsin-involved pathogenic mechanism under PDR, and sheds light on potential therapeutic targets to this debilitating retinal disease.
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Affiliation(s)
- Rui Niu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Jindan Wang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Chao Geng
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Yahong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Lijie Dong
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Lin Liu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Yuwen Chang
- Hetian District People's Hospital, Xinjiang, China
| | - Jianqun Shen
- Hetian District People's Hospital, Xinjiang, China
| | - Zetong Nie
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Yan Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Bojie Hu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
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20
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Yang X, Zhang W, Wen X, Bulinski PJ, Chomchai DA, Arines FM, Liu YY, Sprenger S, Teis D, Klionsky DJ, Li M. TORC1 regulates vacuole membrane composition through ubiquitin- and ESCRT-dependent microautophagy. J Cell Biol 2020; 219:133713. [PMID: 32045480 PMCID: PMC7055007 DOI: 10.1083/jcb.201902127] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 11/22/2019] [Accepted: 01/07/2020] [Indexed: 01/12/2023] Open
Abstract
Cellular adaptation in response to nutrient limitation requires the induction of autophagy and lysosome biogenesis for the efficient recycling of macromolecules. Here, we discovered that starvation and TORC1 inactivation not only lead to the up-regulation of autophagy and vacuole proteins involved in recycling but also result in the down-regulation of many vacuole membrane proteins to supply amino acids as part of a vacuole remodeling process. Down-regulation of vacuole membrane proteins is initiated by ubiquitination, which is accomplished by the coordination of multiple E3 ubiquitin ligases, including Rsp5, the Dsc complex, and a newly characterized E3 ligase, Pib1. The Dsc complex is negatively regulated by TORC1 through the Rim15-Ume6 signaling cascade. After ubiquitination, vacuole membrane proteins are sorted into the lumen for degradation by ESCRT-dependent microautophagy. Thus, our study uncovered a complex relationship between TORC1 inactivation and vacuole biogenesis.
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Affiliation(s)
- Xi Yang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Weichao Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Xin Wen
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Patrick J Bulinski
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Dominic A Chomchai
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Felichi Mae Arines
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Yun-Yu Liu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Simon Sprenger
- Institute for Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - David Teis
- Institute for Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Daniel J Klionsky
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Ming Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
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21
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Forouzanfar F, Read MI, Barreto GE, Sahebkar A. Neuroprotective effects of curcumin through autophagy modulation. IUBMB Life 2019; 72:652-664. [DOI: 10.1002/iub.2209] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/22/2019] [Indexed: 02/07/2023]
Affiliation(s)
- Fatemeh Forouzanfar
- Neuroscience Research CenterMashhad University of Medical Sciences Mashhad Iran
- Department of Neuroscience, Faculty of MedicineMashhad University of Medical Sciences Mashhad Iran
| | - Morgayn I. Read
- Department of PharmacologySchool of Medical Sciences, University of Otago Dunedin New Zealand
| | - George E. Barreto
- Department of Biological SciencesUniversity of Limerick Limerick Ireland
- Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile Santiago Chile
| | - Amirhossein Sahebkar
- Halal Research Center of IRI, FDA Tehran Iran
- Biotechnology Research CenterPharmaceutical Technology Institute, Mashhad University of Medical Sciences Mashhad Iran
- Neurogenic Inflammation Research CenterMashhad University of Medical Sciences Mashhad Iran
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22
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Hartley S, Klionsky DJ. Found art: the yeast vacuole. Autophagy 2019; 15:1638-1644. [PMID: 31305202 DOI: 10.1080/15548627.2019.1638208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Over the past 9 years I have worked with artists who have used various media to portray the process of autophagy. This has included paintings, protein music, a piano composition, a wood sculpture, a quilt, and a dance. Here, I describe a two-part project that focuses on the vacuole/lysosome. In the initial part of the work I assembled the found-art vacuole; the second part involved the work of a professional watercolor artist, who describes his part of the project from a non-scientist's perspective.
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Affiliation(s)
| | - Daniel J Klionsky
- b Life Sciences Institute, University of Michigan , Ann Arbor , MI , USA
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23
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Marshall RS, Vierstra RD. Dynamic Regulation of the 26S Proteasome: From Synthesis to Degradation. Front Mol Biosci 2019; 6:40. [PMID: 31231659 PMCID: PMC6568242 DOI: 10.3389/fmolb.2019.00040] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/09/2019] [Indexed: 01/12/2023] Open
Abstract
All eukaryotes rely on selective proteolysis to control the abundance of key regulatory proteins and maintain a healthy and properly functioning proteome. Most of this turnover is catalyzed by the 26S proteasome, an intricate, multi-subunit proteolytic machine. Proteasomes recognize and degrade proteins first marked with one or more chains of poly-ubiquitin, the addition of which is actuated by hundreds of ligases that individually identify appropriate substrates for ubiquitylation. Subsequent proteasomal digestion is essential and influences a myriad of cellular processes in species as diverse as plants, fungi and humans. Importantly, dysfunction of 26S proteasomes is associated with numerous human pathologies and profoundly impacts crop performance, thus making an understanding of proteasome dynamics critically relevant to almost all facets of human health and nutrition. Given this widespread significance, it is not surprising that sophisticated mechanisms have evolved to tightly regulate 26S proteasome assembly, abundance and activity in response to demand, organismal development and stress. These include controls on transcription and chaperone-mediated assembly, influences on proteasome localization and activity by an assortment of binding proteins and post-translational modifications, and ultimately the removal of excess or damaged particles via autophagy. Intriguingly, the autophagic clearance of damaged 26S proteasomes first involves their modification with ubiquitin, thus connecting ubiquitylation and autophagy as key regulatory events in proteasome quality control. This turnover is also influenced by two distinct biomolecular condensates that coalesce in the cytoplasm, one attracting damaged proteasomes for autophagy, and the other reversibly storing proteasomes during carbon starvation to protect them from autophagic clearance. In this review, we describe the current state of knowledge regarding the dynamic regulation of 26S proteasomes at all stages of their life cycle, illustrating how protein degradation through this proteolytic machine is tightly controlled to ensure optimal growth, development and longevity.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
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Thellung S, Corsaro A, Nizzari M, Barbieri F, Florio T. Autophagy Activator Drugs: A New Opportunity in Neuroprotection from Misfolded Protein Toxicity. Int J Mol Sci 2019; 20:ijms20040901. [PMID: 30791416 PMCID: PMC6412775 DOI: 10.3390/ijms20040901] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/11/2019] [Accepted: 02/14/2019] [Indexed: 02/06/2023] Open
Abstract
The aim of this review is to critically analyze promises and limitations of pharmacological inducers of autophagy against protein misfolding-associated neurodegeneration. Effective therapies against neurodegenerative disorders can be developed by regulating the “self-defense” equipment of neurons, such as autophagy. Through the degradation and recycling of the intracellular content, autophagy promotes neuron survival in conditions of trophic factor deprivation, oxidative stress, mitochondrial and lysosomal damage, or accumulation of misfolded proteins. Autophagy involves the activation of self-digestive pathways, which is different for dynamics (macro, micro and chaperone-mediated autophagy), or degraded material (mitophagy, lysophagy, aggrephagy). All neurodegenerative disorders share common pathogenic mechanisms, including the impairment of autophagic flux, which causes the inability to remove the neurotoxic oligomers of misfolded proteins. Pharmacological activation of autophagy is typically achieved by blocking the kinase activity of mammalian target of rapamycin (mTOR) enzymatic complex 1 (mTORC1), removing its autophagy suppressor activity observed under physiological conditions; acting in this way, rapamycin provided the first proof of principle that pharmacological autophagy enhancement can induce neuroprotection through the facilitation of oligomers’ clearance. The demand for effective disease-modifying strategies against neurodegenerative disorders is currently stimulating the development of a wide number of novel molecules, as well as the re-evaluation of old drugs for their pro-autophagic potential.
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Affiliation(s)
- Stefano Thellung
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Alessandro Corsaro
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Mario Nizzari
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Federica Barbieri
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Tullio Florio
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
- IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy.
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