1
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Pogany J, Inaba JI, Liu Y, Nagy PD. Screening bacterial effectors and human virus proteins in yeast to identify host factors driving tombusvirus RNA recombination: a role for autophagy and membrane phospholipid content. J Virol 2025:e0166124. [PMID: 40422074 DOI: 10.1128/jvi.01661-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2024] [Accepted: 03/27/2025] [Indexed: 05/28/2025] Open
Abstract
Recombination in RNA viruses contributes to virus evolution and rapid emergence of new viral variants that helps evade host's antiviral strategies. Host factors play important but poorly characterized roles in viral RNA recombination. The authors expressed Legionella bacterium effector proteins and SARS-CoV-2 and human metapneumovirus (HMPV) proteins in yeast to test their effects on tomato bushy stunt virus (TBSV) RNA recombination. The identified 16 Legionella effectors, six SARS-CoV-2, and two HMPV proteins affecting TBSV recombination likely target shared host factors with TBSV. Among the targets of the effectors/viral proteins was the autophagy pathway. Inhibition of autophagy by expression of RavZ and LegA9 Legionella effectors reduced the production of TBSV recombinants in yeast and plants. Induction of autophagy by rapamycin, via nitrogen starvation of yeast or overexpression of ATG2 lipid transfer protein, led to enhanced viral RNA recombination. Using in vitro TBSV replicase assembly on giant unilamellar vesicles confirmed the critical role of phosphatidylethanolamine in RNA recombination. We suggest that the pro-recombination role of co-opted autophagy is to provide abundant phospholipids for viral replication organelle biogenesis. Overall, this work highlights the critical roles of membrane phospholipids and lipid context in the regulation of viral RNA recombination. We show that SARS-CoV-2 N and HMPV M2-1 proteins enhance TBSV RNA replication and recombination by protecting the viral RNAs from host Xrn1 5´-3´ exoribonuclease in yeast. Altogether, the novel strategy of using TBSV as a cellular system sensor might assist in the identification of novel functional targets of various viral and bacterial effectors in yeast. IMPORTANCE Positive-strand (+)RNA viruses replicate in the cytosol of infected cells by exploiting cellular proteins and resources that frequently lead to diseases. Virus replication results in the generation of viral RNA recombinants that contribute to the emergence of new viral variants and adaptation to new hosts. The authors expressed Legionella bacterium effector proteins, SARS-CoV-2 and human metapneumovirus proteins in yeast to test their effects on tomato bushy stunt virus (TBSV) RNA recombination. This novel approach revealed that Legionella effectors and heterologous viral proteins target shared host factors with TBSV, including the autophagy pathway. In vitro approach revealed that the pro-recombination role of co-opted autophagy is to provide abundant phospholipids for viral replication. SARS-CoV-2 nucleocapsid protein and human metapneumovirus M2-1 protein are shown to enhance TBSV RNA replication and recombination by protecting the viral RNAs from host Xrn1 5´-3´ exoribonuclease in yeast. Thus, the TBSV/yeast system can be used as a cellular system sensor to find new functions of heterologous viral proteins.
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Affiliation(s)
- Judit Pogany
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Jun-Ichi Inaba
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Yuyan Liu
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
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2
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Zhang T, Lin Y, Zhang Z, Wang Z, Zeng F, Wang Q. Roles and applications of autophagy in guarding against environmental stress and DNA damage in Saccharomyces cerevisiae. FEBS J 2025. [PMID: 40272088 DOI: 10.1111/febs.70112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2025] [Revised: 03/09/2025] [Accepted: 04/07/2025] [Indexed: 04/25/2025]
Abstract
Saccharomyces cerevisiae (S. cerevisiae), a famous chassis cell factory, often faces various environmental stress conditions like extreme temperature, osmolarity, and nutrient starvation during the fermentation process. Additionally, chromosomal replication and genome editing-assisted metabolic engineering may cause DNA damage to S. cerevisiae. S. cerevisiae has evolved multiple elaborate mechanisms to fend against these adverse conditions. One of these "self-repair" mechanisms is autophagy, a ubiquitous "self-eating" mechanism that transports intracellular components to the lysosome/vacuole for degradation. Here, we reviewed the current state of our knowledge about the role and application of autophagy regulation in S. cerevisiae in response to environmental stress and genome damage, which may provide new strategies for developing robust industrial yeast and accelerating genome engineering.
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Affiliation(s)
- Tong Zhang
- College of Science & Technology, Hebei Agricultural University, Cangzhou, Hebei, China
| | - Yuping Lin
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Ziteng Zhang
- College of Science & Technology, Hebei Agricultural University, Cangzhou, Hebei, China
| | - Zhen Wang
- College of Science & Technology, Hebei Agricultural University, Cangzhou, Hebei, China
| | - Fanli Zeng
- College of Life Sciences, Hebei Agricultural University, Baoding, Hebei, China
| | - Qinhong Wang
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
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3
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Nagy PD, Pogany J, Kang Y. Novel exploitation of autophagy by tombusviruses. Virology 2025; 603:110363. [PMID: 39708618 DOI: 10.1016/j.virol.2024.110363] [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: 10/23/2024] [Revised: 12/04/2024] [Accepted: 12/16/2024] [Indexed: 12/23/2024]
Abstract
Positive-strand (+)RNA viruses are major pathogens of humans, animals and plants. This review summarizes the complex interplay between the host autophagy pathway and Tomato bushy stunt virus (TBSV) replication. Recent discoveries with TBSV have revealed virus-driven exploitation of autophagy in multiple ways that contributes to the unique phospholipid composition of viral replication organellar (VROs) membranes. Viral replication protein-driven subversion of phagophore membranes, recruitment of ATG2 bulk lipid transfer protein to enrich phosphatidylethanolamine and phosphatidylserine in VROs, recruitment of VPS34 PI3K to produce PI(3)P; and ATG11-facilitated formation of stable viral membrane contact sites contributes to VRO membrane proliferation. Recruitment of autophagy core proteins to vir-NBR1 bodies within vir-condensates associated with VROs results in dampened antiviral degradation by autophagy. Overall, TBSV intricate interplay with the autophagy machinery highlights the importance of lipid dynamics in viral life cycles and points toward potential directions for therapeutic intervention.
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Affiliation(s)
- Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY, USA.
| | - Judit Pogany
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY, USA
| | - Yuanrong Kang
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY, USA
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4
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Williams TD, Rousseau A. Translation regulation in response to stress. FEBS J 2024; 291:5102-5122. [PMID: 38308808 PMCID: PMC11616006 DOI: 10.1111/febs.17076] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/07/2023] [Accepted: 01/22/2024] [Indexed: 02/05/2024]
Abstract
Cell stresses occur in a wide variety of settings: in disease, during industrial processes, and as part of normal day-to-day rhythms. Adaptation to these stresses requires cells to alter their proteome. Cells modify the proteins they synthesize to aid proteome adaptation. Changes in both mRNA transcription and translation contribute to altered protein synthesis. Here, we discuss the changes in translational mechanisms that occur following the onset of stress, and the impact these have on stress adaptation.
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Affiliation(s)
- Thomas D. Williams
- MRC‐PPU, School of Life SciencesUniversity of DundeeUK
- Sir William Dunn School of PathologyUniversity of OxfordUK
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5
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Fangma Y, Chen Z, Zheng Y. Flexible Atg1/ULK complex composition activates selective autophagy for phosphate starvation. Cell Mol Biol Lett 2024; 29:85. [PMID: 38834954 PMCID: PMC11151501 DOI: 10.1186/s11658-024-00597-3] [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: 03/20/2024] [Accepted: 05/16/2024] [Indexed: 06/06/2024] Open
Abstract
The molecular basis for bulk autophagy activation due to a deficiency in essential nutrients such as carbohydrates, amino acids, and nitrogen is well understood. Given autophagy functions to reduce surplus to compensate for scarcity, it theoretically possesses the capability to selectively degrade specific substrates to meet distinct metabolic demands. However, direct evidence is still lacking that substantiates the idea that autophagy selectively targets specific substrates (known as selective autophagy) to address particular nutritional needs. Recently, Gross et al. found that during phosphate starvation (P-S), rather than nitrogen starvation (N-S), yeasts selectively eliminate peroxisomes by dynamically altering the composition of the Atg1/ULK kinase complex (AKC) to adapt to P-S. This study elucidates how the metabolite sensor Pho81 flexibly interacts with AKC and guides selective autophagic clearance of peroxisomes during P-S, providing novel insights into the metabolic contribution of autophagy to special nutritional needs.
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Affiliation(s)
- Yijia Fangma
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Yanrong Zheng
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
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6
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Gross AS, Ghillebert R, Schuetter M, Reinartz E, Rowland A, Bishop BC, Stumpe M, Dengjel J, Graef M. A metabolite sensor subunit of the Atg1/ULK complex regulates selective autophagy. Nat Cell Biol 2024; 26:366-377. [PMID: 38316984 PMCID: PMC10940145 DOI: 10.1038/s41556-024-01348-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/03/2024] [Indexed: 02/07/2024]
Abstract
Cells convert complex metabolic information into stress-adapted autophagy responses. Canonically, multilayered protein kinase networks converge on the conserved Atg1/ULK kinase complex (AKC) to induce non-selective and selective forms of autophagy in response to metabolic changes. Here we show that, upon phosphate starvation, the metabolite sensor Pho81 interacts with the adaptor subunit Atg11 at the AKC via an Atg11/FIP200 interaction motif to modulate pexophagy by virtue of its conserved phospho-metabolite sensing SPX domain. Notably, core AKC components Atg13 and Atg17 are dispensable for phosphate starvation-induced autophagy revealing significant compositional and functional plasticity of the AKC. Our data indicate that, instead of functioning as a selective autophagy receptor, Pho81 compensates for partially inactive Atg13 by promoting Atg11 phosphorylation by Atg1 critical for pexophagy during phosphate starvation. Our work shows Atg11/FIP200 adaptor subunits bind not only selective autophagy receptors but also modulator subunits that convey metabolic information directly to the AKC for autophagy regulation.
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Affiliation(s)
- A S Gross
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
- Gregor Mendel Institute of Molecular Plant Biology, Vienna Biocenter, Vienna, Austria
| | - R Ghillebert
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - M Schuetter
- Max Planck Research Metabolomics Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - E Reinartz
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - A Rowland
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - B C Bishop
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - M Stumpe
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - J Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - M Graef
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany.
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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7
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Kang Y, Lin W, Nagy PD. Subversion of selective autophagy for the biogenesis of tombusvirus replication organelles inhibits autophagy. PLoS Pathog 2024; 20:e1012085. [PMID: 38484009 DOI: 10.1371/journal.ppat.1012085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 03/26/2024] [Accepted: 02/29/2024] [Indexed: 03/27/2024] Open
Abstract
Elaborate viral replication organelles (VROs) are formed to support positive-strand RNA virus replication in infected cells. VRO formation requires subversion of intracellular membranes by viral replication proteins. Here, we showed that the key ATG8f autophagy protein and NBR1 selective autophagy receptor were co-opted by Tomato bushy stunt virus (TBSV) and the closely-related carnation Italian ringspot virus. Knockdown of ATG8f or NBR1 in plants led to reduced tombusvirus replication, suggesting pro-viral function for selective autophagy. BiFC and proximity-labeling experiments showed that the TBSV p33 replication protein interacted with ATG8f and NBR1 to recruit them to VROs. In addition, we observed that several core autophagy proteins, such as ATG1a, ATG4, ATG5, ATG101 and the plant-specific SH3P2 autophagy adaptor proteins were also re-localized to TBSV VROs, suggesting that TBSV hijacks the autophagy machinery in plant cells. We demonstrated that subversion of autophagy components facilitated the recruitment of VPS34 PI3 kinase and enrichment of phospholipids, such as phosphatidylethanolamine and PI3P phosphoinositide in the VRO membranes. Hijacking of autophagy components into TBSV VROs led to inhibition of autophagic flux. We also found that a fraction of the subverted ATG8f and NBR1 was sequestered in biomolecular condensates associated with VROs. We propose that the VRO-associated condensates trap those autophagy proteins, taking them away from the autophagy pathway. Overall, tombusviruses hijack selective autophagy to provide phospholipid-rich membranes for replication and to regulate the antiviral autophagic flux.
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Affiliation(s)
- Yuanrong Kang
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Wenwu Lin
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
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8
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Kim DH. Contrasting views on the role of AMPK in autophagy. Bioessays 2024; 46:e2300211. [PMID: 38214366 PMCID: PMC10922896 DOI: 10.1002/bies.202300211] [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: 11/01/2023] [Revised: 01/01/2024] [Accepted: 01/04/2024] [Indexed: 01/13/2024]
Abstract
Efficient management of low energy states is vital for cells to maintain basic functions and metabolism and avoid cell death. While autophagy has long been considered a critical mechanism for ensuring survival during energy depletion, recent research has presented conflicting evidence, challenging the long-standing concept. This recent development suggests that cells prioritize preserving essential cellular components while restraining autophagy induction when cellular energy is limited. This essay explores the conceptual discourse on autophagy regulation during energy stress, navigating through the studies that established the current paradigm and the recent research that has challenged its validity while proposing an alternative model. This exploration highlights the far-reaching implications of the alternative model, which represents a conceptual departure from the established paradigm, offering new perspectives on how cells respond to energy stress.
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Affiliation(s)
- Do-Hyung Kim
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
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9
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Bhattacharya A, Torggler R, Reiter W, Romanov N, Licheva M, Ciftci A, Mari M, Kolb L, Kaiser D, Reggiori F, Ammerer G, Hollenstein DM, Kraft C. Decoding the function of Atg13 phosphorylation reveals a role of Atg11 in bulk autophagy initiation. EMBO Rep 2024; 25:813-831. [PMID: 38233718 PMCID: PMC10897315 DOI: 10.1038/s44319-023-00055-9] [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: 07/14/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 01/19/2024] Open
Abstract
Autophagy is initiated by the assembly of multiple autophagy-related proteins that form the phagophore assembly site where autophagosomes are formed. Atg13 is essential early in this process, and a hub of extensive phosphorylation. How these multiple phosphorylations contribute to autophagy initiation, however, is not well understood. Here we comprehensively analyze the role of phosphorylation events on Atg13 during nutrient-rich conditions and nitrogen starvation. We identify and functionally characterize 48 in vivo phosphorylation sites on Atg13. By generating reciprocal mutants, which mimic the dephosphorylated active and phosphorylated inactive state of Atg13, we observe that disrupting the dynamic regulation of Atg13 leads to insufficient or excessive autophagy, which are both detrimental to cell survival. We furthermore demonstrate an involvement of Atg11 in bulk autophagy even during nitrogen starvation, where it contributes together with Atg1 to the multivalency that drives phase separation of the phagophore assembly site. These findings reveal the importance of post-translational regulation on Atg13 early during autophagy initiation, which provides additional layers of regulation to control bulk autophagy activity and integrate cellular signals.
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Affiliation(s)
- Anuradha Bhattacharya
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104, Freiburg, Germany
| | - Raffaela Torggler
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Wolfgang Reiter
- Department for Biochemistry and Cell Biology, University of Vienna, Center for Molecular Biology, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9, 1030, Vienna, Austria
- Mass Spectrometry Facility, Max Perutz Labs, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 7, Vienna, Austria
| | - Natalie Romanov
- Department for Biochemistry and Cell Biology, University of Vienna, Center for Molecular Biology, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9, 1030, Vienna, Austria
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Akif Ciftci
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Muriel Mari
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark
| | - Lena Kolb
- Department for Biochemistry and Cell Biology, University of Vienna, Center for Molecular Biology, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Dominik Kaiser
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark
| | - Gustav Ammerer
- Department for Biochemistry and Cell Biology, University of Vienna, Center for Molecular Biology, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - David M Hollenstein
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.
- Department for Biochemistry and Cell Biology, University of Vienna, Center for Molecular Biology, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9, 1030, Vienna, Austria.
- Mass Spectrometry Facility, Max Perutz Labs, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 7, Vienna, Austria.
| | - 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.
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10
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Metur SP, Klionsky DJ. Nutrient-dependent signaling pathways that control autophagy in yeast. FEBS Lett 2024; 598:32-47. [PMID: 37758520 PMCID: PMC10841420 DOI: 10.1002/1873-3468.14741] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023]
Abstract
Macroautophagy/autophagy is a highly conserved catabolic process vital for cellular stress responses and maintaining equilibrium within the cell. Malfunctioning autophagy has been implicated in the pathogenesis of various diseases, including certain neurodegenerative disorders, diabetes, metabolic diseases, and cancer. Cells face diverse metabolic challenges, such as limitations in nitrogen, carbon, and minerals such as phosphate and iron, necessitating the integration of complex metabolic information. Cells utilize a signal transduction network of sensors, transducers, and effectors to coordinate the execution of the autophagic response, concomitant with the severity of the nutrient-starvation condition. This review presents the current mechanistic understanding of how cells regulate the initiation of autophagy through various nutrient-dependent signaling pathways. Emphasizing findings from studies in yeast, we explore the emerging principles that underlie the nutrient-dependent regulation of autophagy, significantly shaping stress-induced autophagy responses under various metabolic stress conditions.
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Affiliation(s)
- Shree Padma Metur
- Department of Molecular, Cellular and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Daniel J Klionsky
- Department of Molecular, Cellular and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
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11
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Feng Y, Chen Y, Wu X, Chen J, Zhou Q, Liu B, Zhang L, Yi C. Interplay of energy metabolism and autophagy. Autophagy 2024; 20:4-14. [PMID: 37594406 PMCID: PMC10761056 DOI: 10.1080/15548627.2023.2247300] [Citation(s) in RCA: 53] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/19/2023] Open
Abstract
Macroautophagy/autophagy, is widely recognized for its crucial role in enabling cell survival and maintaining cellular energy homeostasis during starvation or energy stress. Its regulation is intricately linked to cellular energy status. In this review, covering yeast, mammals, and plants, we aim to provide a comprehensive overview of the understanding of the roles and mechanisms of carbon- or glucose-deprivation related autophagy, showing how cells effectively respond to such challenges for survival. Further investigation is needed to determine the specific degraded substrates by autophagy during glucose or energy deprivation and the diverse roles and mechanisms during varying durations of energy starvation.Abbreviations: ADP: adenosine diphosphate; AMP: adenosine monophosphate; AMPK: AMP-activated protein kinase; ATG: autophagy related; ATP: adenosine triphosphate; ER: endoplasmic reticulum; ESCRT: endosomal sorting complex required for transport; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GD: glucose deprivation; GFP: green fluorescent protein; GTPases: guanosine triphosphatases; HK2: hexokinase 2; K phaffii: Komagataella phaffii; LD: lipid droplet; MAP1LC3/LC3: microtubule-associated protein1 light chain 3; MAPK: mitogen-activated protein kinase; Mec1: mitosis entry checkpoint 1; MTOR: mechanistic target of rapamycin kinase; NAD (+): nicotinamide adenine dinucleotide; OGD: oxygen and glucose deprivation; PAS: phagophore assembly site; PCD: programmed cell death; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; ROS: reactive oxygen species; S. cerevisiae: Saccharomyces cerevisiae; SIRT1: sirtuin 1; Snf1: sucrose non-fermenting 1; STK11/LKB1: serine/threonine kinase 11; TFEB: transcription factor EB; TORC1: target of rapamycin complex 1; ULK1: unc-51 like kinase 1; Vps27: vacuolar protein sorting 27; Vps4: vacuolar protein sorting 4.
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Affiliation(s)
- Yuyao Feng
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University, Huzhou, China
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China
| | - Ying Chen
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoyong Wu
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Junye Chen
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China
| | - Qingyan Zhou
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bao Liu
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China
| | - Liqin Zhang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University, Huzhou, China
| | - Cong Yi
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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12
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Chiu CY, Lung HF, Chou WC, Lin LY, Chow HX, Kuo YH, Chien PS, Chiou TJ, Liu TY. Autophagy-Mediated Phosphate Homeostasis in Arabidopsis Involves Modulation of Phosphate Transporters. PLANT & CELL PHYSIOLOGY 2023; 64:519-535. [PMID: 36943363 DOI: 10.1093/pcp/pcad015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 01/31/2023] [Accepted: 03/01/2023] [Indexed: 05/17/2023]
Abstract
Autophagy in plants is regulated by diverse signaling cascades in response to environmental changes. Fine-tuning of its activity is critical for the maintenance of cellular homeostasis under basal and stressed conditions. In this study, we compared the Arabidopsis autophagy-related (ATG) system transcriptionally under inorganic phosphate (Pi) deficiency versus nitrogen deficiency and showed that most ATG genes are only moderately upregulated by Pi starvation, with relatively stronger induction of AtATG8f and AtATG8h among the AtATG8 family. We found that Pi shortage increased the formation of GFP-ATG8f-labeled autophagic structures and the autophagic flux in the differential zone of the Arabidopsis root. However, the proteolytic cleavage of GFP-ATG8f and the vacuolar degradation of endogenous ATG8 proteins indicated that Pi limitation does not drastically alter the autophagic flux in the whole roots, implying a cell type-dependent regulation of autophagic activities. At the organismal level, the Arabidopsis atg mutants exhibited decreased shoot Pi concentrations and smaller meristem sizes under Pi sufficiency. Under Pi limitation, these mutants showed enhanced Pi uptake and impaired root cell division and expansion. Despite a reduced steady-state level of several PHOSPHATE TRANSPORTER 1s (PHT1s) in the atg root, cycloheximide treatment analysis suggested that the protein stability of PHT1;1/2/3 is comparable in the Pi-replete wild type and atg5-1. By contrast, the degradation of PHT1;1/2/3 is enhanced in the Pi-deplete atg5-1. Our findings reveal that both basal autophagy and Pi starvation-induced autophagy are required for the maintenance of Pi homeostasis and may modulate the expression of PHT1s through different mechanisms.
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Affiliation(s)
- Chang-Yi Chiu
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Hui-Fang Lung
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Wen-Chun Chou
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Li-Yen Lin
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Hong-Xuan Chow
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Yu-Hao Kuo
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
| | - Pei-Shan Chien
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Tzyy-Jen Chiou
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Tzu-Yin Liu
- Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
- Department of Life Science, College of Life Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., East Dist., Hsinchu 30013, Taiwan
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13
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Wang YN, Liu FJ, Liu HD, Zhang Y, Jiao X, Ye ML, Zhao ZBK, Zhang SF. Regulation of autophagy and lipid accumulation under phosphate limitation in Rhodotorula toruloides. Front Microbiol 2023; 13:1046114. [PMID: 36777022 PMCID: PMC9908577 DOI: 10.3389/fmicb.2022.1046114] [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: 09/16/2022] [Accepted: 12/23/2022] [Indexed: 01/27/2023] Open
Abstract
Background It is known that autophagy is essential for cell survival under stress conditions. Inorganic phosphate (Pi) is an essential nutrient for cell growth and Pi-limitation can trigger autophagy and lipid accumulation in oleaginous yeasts, yet protein (de)-phosphorylation and related signaling events in response to Pi limitation and the molecular basis linking Pi-limitation to autophagy and lipid accumulation remain elusive. Results Here, we compared the proteome and phosphoproteome of Rhodotorula toruloides CGMCC 2.1389 under Pi-limitation and Pi-repletion. In total, proteome analysis identified 3,556 proteins and the phosphoproteome analysis identified 1,649 phosphoproteins contained 5,659 phosphosites including 4,499 pSer, 978 pThr, and 182 pTyr. We found Pi-starvation-induced autophagy was regulated by autophagy-related proteins, but not the PHO pathway. When ATG9 was knocked down, the engineered strains produced significantly less lipids under Pi-limitation, suggesting that autophagy required Atg9 in R. toruloides and that was conducive to lipid accumulation. Conclusion Our results provide new insights into autophagy regulation under Pi-limitation and lipid accumulation in oleaginous yeast, which should be valuable to guide further mechanistic study of oleaginicity and genetic engineering for advanced lipid producing cell factory.
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Affiliation(s)
- Ya-nan Wang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Fang-jie Liu
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Hong-di Liu
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Yue Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Xiang Jiao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Ming-liang Ye
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, CAS, Dalian, China,Ming-liang Ye,
| | - Zong-bao Kent Zhao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Zong-bao Kent Zhao,
| | - Su-fang Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,*Correspondence: Su-fang Zhang, ,
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14
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Abstract
Most cells live in environments that are permissive for proliferation only a small fraction of the time. Entering quiescence enables cells to survive long periods of nondivision and reenter the cell cycle when signaled to do so. Here, we describe what is known about the molecular basis for quiescence in Saccharomyces cerevisiae, with emphasis on the progress made in the last decade. Quiescence is triggered by depletion of an essential nutrient. It begins well before nutrient exhaustion, and there is extensive crosstalk between signaling pathways to ensure that all proliferation-specific activities are stopped when any one essential nutrient is limiting. Every aspect of gene expression is modified to redirect and conserve resources. Chromatin structure and composition change on a global scale, from histone modifications to three-dimensional chromatin structure. Thousands of proteins and RNAs aggregate, forming unique structures with unique fates, and the cytoplasm transitions to a glass-like state.
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Affiliation(s)
- Linda L Breeden
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA; ,
| | - Toshio Tsukiyama
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA; ,
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15
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Sharma I, Kirti PB, Pati PK. Autophagy: a game changer for plant development and crop improvement. PLANTA 2022; 256:103. [PMID: 36307739 DOI: 10.1007/s00425-022-04004-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Manipulation of autophagic pathway represents a tremendous opportunity for designing climate-smart crops with improved yield and better adaptability to changing environment. For exploiting autophagy to its full potential, identification and comprehensive characterization of adapters/receptor complex and elucidation of its regulatory network in crop plants is highly warranted. Autophagy is a major intracellular trafficking pathway in eukaryotes involved in vacuolar degradation of cytoplasmic constituents, mis-folded proteins, and defective organelles. Under optimum conditions, autophagy operates at a basal level to maintain cellular homeostasis, but under stressed conditions, it is induced further to provide temporal stress relief. Our understanding of this highly dynamic process has evolved exponentially in the past few years with special reference to several plant-specific roles of autophagy. Here, we review the most recent advances in the field of autophagy in plants and discuss its potential implications in designing crops with improved stress and disease-tolerance, enhanced yield potential, and improved capabilities for producing metabolites of high economic value. We also assess the current knowledge gaps and the possible strategies to develop a robust module for biotechnological application of autophagy to enhance bioeconomy and sustainability of agriculture.
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Affiliation(s)
- Isha Sharma
- AgriBiotech Foundation, PJTS Agriculture University, Rajendranagar, Hyderabad, Telangana, 500032, India.
- International Crops Research Institute for the Semi-Arid Tropics, 502324, Patancheru, Telangana, India.
| | | | - Pratap Kumar Pati
- Department of Biotechnology, Guru Nanak Dev University, Amritsar, Punjab, 140301, India
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16
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Li L, Lee CP, Ding X, Qin Y, Wijerathna-Yapa A, Broda M, Otegui MS, Millar AH. Defects in autophagy lead to selective in vivo changes in turnover of cytosolic and organelle proteins in Arabidopsis. THE PLANT CELL 2022; 34:3936-3960. [PMID: 35766863 PMCID: PMC9516138 DOI: 10.1093/plcell/koac185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/21/2022] [Indexed: 05/26/2023]
Abstract
Identification of autophagic protein cargo in plants in autophagy-related genes (ATG) mutants is complicated by changes in protein synthesis and protein degradation. To detect autophagic cargo, we measured protein degradation rate in shoots and roots of Arabidopsis (Arabidopsis thaliana) atg5 and atg11 mutants. These data show that less than a quarter of proteins changing in abundance are probable cargo and revealed roles of ATG11 and ATG5 in degradation of specific glycolytic enzymes and of other cytosol, chloroplast, and ER-resident proteins, and a specialized role for ATG11 in degradation of proteins from mitochondria and chloroplasts. Protein localization in transformed protoplasts and degradation assays in the presence of inhibitors confirm a role for autophagy in degrading glycolytic enzymes. Autophagy induction by phosphate (Pi) limitation changed metabolic profiles and the protein synthesis and degradation rates of atg5 and atg11 plants. A general decrease in the abundance of amino acids and increase in secondary metabolites in autophagy mutants was consistent with altered catabolism and changes in energy conversion caused by reduced degradation rate of specific proteins. Combining measures of changes in protein abundance and degradation rates, we also identify ATG11 and ATG5-associated protein cargo of low Pi-induced autophagy in chloroplasts and ER-resident proteins involved in secondary metabolism.
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Affiliation(s)
- Lei Li
- Authors for correspondence (L.L.) and (A.H.M)
| | - Chun Pong Lee
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, Crawley, WA 6009, Australia
| | - Xinxin Ding
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Yu Qin
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Akila Wijerathna-Yapa
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, Crawley, WA 6009, Australia
| | - Martyna Broda
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, Crawley, WA 6009, Australia
| | - Marisa S Otegui
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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17
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Kang Y, Lin W, Liu Y, Nagy PD. Key tethering function of Atg11 autophagy scaffold protein in formation of virus-induced membrane contact sites during tombusvirus replication. Virology 2022; 572:1-16. [DOI: 10.1016/j.virol.2022.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/15/2022] [Accepted: 04/25/2022] [Indexed: 01/04/2023]
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18
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Reggiori F, Molinari M. ER-phagy: mechanisms, regulation and diseases connected to the lysosomal clearance of the endoplasmic reticulum. Physiol Rev 2022; 102:1393-1448. [PMID: 35188422 PMCID: PMC9126229 DOI: 10.1152/physrev.00038.2021] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
ER-phagy (reticulo-phagy) defines the degradation of portions of the endoplasmic reticulum (ER) within lysosomes or vacuoles. It is part of the self-digestion (i.e., auto-phagic) programs recycling cytoplasmic material and organelles, which rapidly mobilize metabolites in cells confronted with nutrient shortage. Moreover, selective clearance of ER subdomains participates to the control of ER size and activity during ER stress, the re-establishment of ER homeostasis after ER stress resolution and the removal of ER parts, in which aberrant and potentially cytotoxic material has been segregated. ER-phagy relies on the individual and/or concerted activation of the ER-phagy receptors, ER peripheral or integral membrane proteins that share the presence of LC3/Atg8-binding motifs in their cytosolic domains. ER-phagy involves the physical separation of portions of the ER from the bulk ER network, and their delivery to the endolysosomal/vacuolar catabolic district. This last step is accomplished by a variety of mechanisms including macro-ER-phagy (in which ER fragments are sequestered by double-membrane autophagosomes that eventually fuse with lysosomes/vacuoles), micro-ER-phagy (in which ER fragments are directly engulfed by endosomes/lysosomes/vacuoles), or direct fusion of ER-derived vesicles with lysosomes/vacuoles. ER-phagy is dysfunctional in specific human diseases and its regulators are subverted by pathogens, highlighting its crucial role for cell and organism life.
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Affiliation(s)
- Fulvio Reggiori
- Department of Biomedical Sciences of Cells & Systems, grid.4830.fUniversity of Groningen, Netherlands
| | - Maurizio Molinari
- Protein Folding and Quality Control, grid.7722.0Institute for Research in Biomedicine, Bellinzona, Switzerland
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19
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Waite KA, Burris A, Vontz G, Lang A, Roelofs J. Proteaphagy is specifically regulated and requires factors dispensable for general autophagy. J Biol Chem 2022; 298:101494. [PMID: 34919962 PMCID: PMC8732087 DOI: 10.1016/j.jbc.2021.101494] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 12/27/2022] Open
Abstract
Changing physiological conditions can increase the need for protein degradative capacity in eukaryotic cells. Both the ubiquitin-proteasome system and autophagy contribute to protein degradation. However, these processes can be differently regulated depending on the physiological conditions. Strikingly, proteasomes themselves can be a substrate for autophagy. The signals and molecular mechanisms that govern proteasome autophagy (proteaphagy) are only partly understood. Here, we used immunoblots, native gel analyses, and fluorescent microscopy to understand the regulation of proteaphagy in response to genetic and small molecule-induced perturbations. Our data indicate that chemical inhibition of the master nutrient sensor TORC1 (inhibition of which induces general autophagy) with rapamycin induces a bi-phasic response where proteasome levels are upregulated after an autophagy-dependent reduction. Surprisingly, several conditions that result in inhibited TORC1, such as caffeinine treatment or nitrogen starvation, only induced proteaphagy (i.e., without any proteasome upregulation), suggesting a convergence of signals upstream of proteaphagy under different physiological conditions. Indeed, we found that several conditions that activated general autophagy did not induce proteaphagy, further distinguishing proteaphagy from general autophagy. Consistent with this, we show that Atg11, a selective autophagy receptor, as well as the MAP kinases Mpk1, Mkk1, and Mkk2 all play a role in autophagy of proteasomes, although they are dispensable for general autophagy. Taken together, our data provide new insights into the molecular regulation of proteaphagy by demonstrating that degradation of proteasome complexes is specifically regulated under different autophagy-inducing conditions.
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Affiliation(s)
- Kenrick A Waite
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Alicia Burris
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA; Biology & Environmental Health, Missouri Southern State University, Joplin, Missouri, USA
| | - Gabrielle Vontz
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Angelica Lang
- Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Jeroen Roelofs
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA.
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20
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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: 17] [Impact Index Per Article: 4.3] [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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21
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Montella-Manuel S, Pujol-Carrion N, de la Torre-Ruiz MA. The Cell Wall Integrity Receptor Mtl1 Contributes to Articulate Autophagic Responses When Glucose Availability Is Compromised. J Fungi (Basel) 2021; 7:903. [PMID: 34829194 PMCID: PMC8623553 DOI: 10.3390/jof7110903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 01/02/2023] Open
Abstract
Mtl1protein is a cell wall receptor belonging to the CWI pathway. Mtl1 function is related to glucose and oxidative stress signaling. In this report, we show data demonstrating that Mtl1 plays a critical role in the detection of a descent in glucose concentration, in order to activate bulk autophagy machinery as a response to nutrient deprivation and to maintain cell survival in starvation conditions. Autophagy is a tightly regulated mechanism involving several signaling pathways. The data here show that in Saccharomyces cerevisiae, Mtl1 signals glucose availability to either Ras2 or Sch9 proteins converging in Atg1 phosphorylation and autophagy induction. TORC1 complex function is not involved in autophagy induction during the diauxic shift when glucose is limited. In this context, the GCN2 gene is required to regulate autophagy activation upon amino acid starvation independent of the TORC1 complex. Mtl1 function is also involved in signaling the autophagic degradation of mitochondria during the stationary phase through both Ras2 and Sch9, in a manner dependent on either Atg33 and Atg11 proteins and independent of the Atg32 protein, the mitophagy receptor. All of the above suggest a pivotal signaling role for Mtl1 in maintaining correct cell homeostasis function in periods of glucose scarcity in budding yeast.
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Affiliation(s)
| | | | - Maria Angeles de la Torre-Ruiz
- Cell Signalling in Yeast Unit, Department of Basic Medical Sciences, Institut de Recerca Biomèdica de Lleida (IRBLleida), University of Lleida, 25198 Lleida, Spain; (S.M.-M.); (N.P.-C.)
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22
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Corral-Ramos C, Barrios R, Ayté J, Hidalgo E. TOR and MAP kinase pathways synergistically regulate autophagy in response to nutrient depletion in fission yeast. Autophagy 2021; 18:375-390. [PMID: 34157946 DOI: 10.1080/15548627.2021.1935522] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
General autophagy is an evolutionarily conserved process in eukaryotes, by which intracellular materials are transported into and degraded inside lysosomes or vacuoles, with the main goal of recycling those materials during periods of starvation. The molecular bases of autophagy have been widely described in Saccharomyces cerevisiae, and the specific roles of Atg proteins in the process were first characterized in this model system. Important contributions have been made in Schizosaccharomyces pombe highlighting the evolutionary similarity and, at the same time, diversity of Atg components in autophagy. However, little is known regarding signals, pathways and role of autophagy in this distant yeast. Here, we undertake a global approach to investigate the signals, the pathways and the consequences of autophagy activation. We demonstrate that not only nitrogen but several nutritional deprivations including lack of carbon, sulfur, phosphorus or leucine sources, trigger autophagy, and that the TORC1, TORC2 and MAP kinase Sty1 pathways control the onset of autophagy. Furthermore, we identify an unexpected phenotype of autophagy-defective mutants, namely their inability to survive in the absence of leucine when biosynthesis of this amino acid is impaired.Abbreviations: ATG: autophagy-related; cAMP: cyclic adenosine monophosphate; cDNA: complementary deoxyribonucleic acid; GFP: green fluorescence protein; Gluc: glucose; Leu: leucine; MAP: mitogen-activated protein; MM: minimal medium; PI: propidium iodine; PKA: protein kinase A; RNA: ribonucleic acid; RT-qPCR: real time quantitative polymerase chain reaction; S. cerevisiae: Saccharomyces cerevisiae; S. pombe: Schizosaccharomyces pombe; TCA: trichloroacetic acid; TOR: target of rapamycin; TORC1: target of rapamycin complex 1; TORC2: target of rapamycin complex 2; YE5S: yeast extract 5 amino acid supplemented.
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Affiliation(s)
| | - Rubén Barrios
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
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23
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Shi M, Shepard S, Zhou Z, Maique J, Seli O, Moe OW, Hu MC. High Dietary Phosphate Exacerbates and Acts Independently of Low Autophagy Activity in Pathological Cardiac Remodeling and Dysfunction. Cells 2021; 10:777. [PMID: 33915953 PMCID: PMC8065663 DOI: 10.3390/cells10040777] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 11/21/2022] Open
Abstract
High phosphate contributes to uremic cardiomyopathy. Abnormal autophagy is associated with the development and progression of heart disease. What is unknown is the effects of phosphate on autophagy and whether the ill effects of phosphate on cardiomyocytes are mediated by low autophagy. High (2.0% w/w)-phosphate diet reduced LC3 puncta in cardiomyocytes and ratio of LC3 II/I and increased p62 protein, indicating that autophagy activity was suppressed. Mice with cardiomyocyte-specific deletion of autophagy-related protein 5 (H-atg5-/-) had reduced autophagy only in the heart, developed cardiac dysfunction with hypertrophy and fibrosis, and had a short lifespan. When H-atg5-/- mice were fed a high-phosphate diet, they developed more apoptosis in cardiomyocytes, more severe cardiac remodeling, and shorter lifespan than normal phosphate-fed H-atg5-/- mice, indicating that cardiac phosphotoxicity is imparted independently of atg5. In conclusion, although high phosphate suppresses autophagy, high phosphate and low autophagy independently trigger and additionally amplify cardiac remodeling and dysfunction.
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Affiliation(s)
- Mingjun Shi
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (M.S.); (S.S.); (Z.Z.); (J.M.); (O.S.)
| | - Sierra Shepard
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (M.S.); (S.S.); (Z.Z.); (J.M.); (O.S.)
| | - Zhiyong Zhou
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (M.S.); (S.S.); (Z.Z.); (J.M.); (O.S.)
| | - Jenny Maique
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (M.S.); (S.S.); (Z.Z.); (J.M.); (O.S.)
| | - Olivia Seli
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (M.S.); (S.S.); (Z.Z.); (J.M.); (O.S.)
| | - Orson W. Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (M.S.); (S.S.); (Z.Z.); (J.M.); (O.S.)
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ming Chang Hu
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; (M.S.); (S.S.); (Z.Z.); (J.M.); (O.S.)
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24
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Pan ZQ, Shao GC, Liu XM, Chen Q, Dong MQ, Du LL. Atg1 kinase in fission yeast is activated by Atg11-mediated dimerization and cis-autophosphorylation. eLife 2020; 9:58073. [PMID: 32909946 PMCID: PMC7511232 DOI: 10.7554/elife.58073] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 09/10/2020] [Indexed: 12/28/2022] Open
Abstract
Autophagy is a proteolytic pathway that is conserved from yeasts to mammals. Atg1 kinase is essential for autophagy, but how its activity is controlled remains insufficiently understood. Here, we show that, in the fission yeast Schizosaccharomyces pombe, Atg1 kinase activity requires Atg11, the ortholog of mammalian FIP200/RB1CC1, but does not require Atg13, Atg17, or Atg101. Remarkably, a 62 amino acid region of Atg11 is sufficient for the autophagy function of Atg11 and for supporting the Atg1 kinase activity. This region harbors an Atg1-binding domain and a homodimerization domain. Dimerizing Atg1 is the main role of Atg11, as it can be bypassed by artificially dimerizing Atg1. In an Atg1 dimer, only one Atg1 molecule needs to be catalytically active, suggesting that Atg1 activation can be achieved through cis-autophosphorylation. We propose that mediating Atg1 oligomerization and activation may be a conserved function of Atg11/FIP200 family proteins and cis-autophosphorylation may be a general mechanism of Atg1 activation.
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Affiliation(s)
- Zhao-Qian Pan
- College of Life Sciences, Beijing Normal University, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Guang-Can Shao
- National Institute of Biological Sciences, Beijing, China
| | - Xiao-Man Liu
- National Institute of Biological Sciences, Beijing, China
| | - Quan Chen
- National Institute of Biological Sciences, Beijing, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
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25
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Yao W, Li Y, Wu L, Wu C, Zhang Y, Liu J, He Z, Wu X, Lu C, Wang L, Zhong H, Hong Z, Xu S, Liu W, Yi C. Atg11 is required for initiation of glucose starvation-induced autophagy. Autophagy 2020; 16:2206-2218. [PMID: 31971848 DOI: 10.1080/15548627.2020.1719724] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
How energy deprivation induces macroautophagy/autophagy is not fully understood. Here, we show that Atg11, a receptor protein for cargo recognition in selective autophagy, is required for the initiation of glucose starvation-induced autophagy. Upon glucose starvation, Atg11 facilitates the interaction between Snf1 and Atg1, thus is required for Snf1-dependent Atg1 activation. Phagophore assembly site (PAS) formation requires Atg11 via its control of the association of Atg17 with Atg29-Atg31. The binding of Atg11 with Atg9 is crucial for recruiting Atg9 vesicles to the PAS and, thus, glucose starvation-induced autophagy. We propose Atg11 as a key initiation factor controlling multiple key steps in energy deprivation-induced autophagy. Abbreviations: AMPK: AMP-activated protein kinase; Ams1: α-mannosidase; Ape1: aminopeptidase I; Cvt: cytoplasm-to-vacuole targeting; GAPDH: glyceraldehyde 3-phosphate dehydrogenase; GFP: green fluorescent protein; MBP: myelin basic protein; MMS: methanesulfonate; PAS: phagophore assembly site; PNBM: p-nitrobenzyl mesylate; SD-G: glucose starvation medium; SD-N: nitrogen starvation medium; ULK1, unc-51 like autophagy activating kinase 1; WT: wild type.
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Affiliation(s)
- Weijing Yao
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou, China
| | - Yixing Li
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou, China
| | - Liming Wu
- Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou, China
| | - Choufei Wu
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University , Huzhou, China
| | - Yi Zhang
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University , Ganzhou, China
| | - Jing Liu
- Institute of Translational Medicine, Zhejiang University School of Medicine , Hangzhou, China
| | - Zhiyong He
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University , Ganzhou, China
| | - Xiaoyong Wu
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou, China
| | - Chenjun Lu
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou, China
| | - Liefeng Wang
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University , Ganzhou, China
| | - Huiming Zhong
- Department of Emergency, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University , Hangzhou, China
| | - Zhi Hong
- ZJU-UoE Institute, Zhejiang University School of Medicine, Zhejiang University , Haining, China
| | - Shiming Xu
- Institute of Translational Medicine, Zhejiang University School of Medicine , Hangzhou, China
| | - Wei Liu
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou, China
| | - Cong Yi
- Department of Biochemistry, and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine , Hangzhou, China
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26
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Mechanisms of Autophagy in Metabolic Stress Response. J Mol Biol 2020; 432:28-52. [DOI: 10.1016/j.jmb.2019.09.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/06/2019] [Accepted: 09/06/2019] [Indexed: 01/17/2023]
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27
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Umekawa M, Shiraishi D, Fuwa M, Sawaguchi K, Mashima Y, Katayama T, Karita S. Mitotic cyclin Clb4 is required for the intracellular adaptation to glucose starvation inSaccharomyces cerevisiae. FEBS Lett 2019; 594:1329-1338. [DOI: 10.1002/1873-3468.13722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/08/2019] [Accepted: 12/09/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Midori Umekawa
- Graduate School of Bioresources Mie University Tsu Japan
| | | | - Marin Fuwa
- Faculty of Bioresources Mie University Tsu Japan
| | | | | | | | - Shuichi Karita
- Graduate School of Bioresources Mie University Tsu Japan
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28
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Iwama R, Ohsumi Y. Analysis of autophagy activated during changes in carbon source availability in yeast cells. J Biol Chem 2019; 294:5590-5603. [PMID: 30755486 DOI: 10.1074/jbc.ra118.005698] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/05/2019] [Indexed: 11/06/2022] Open
Abstract
Autophagy is a conserved intracellular degradation system in eukaryotes. Recent studies have revealed that autophagy can be induced not only by nitrogen starvation but also by many other stimuli. However, questions persist regarding the types of conditions that induce autophagy, as well as the particular kinds of autophagy that are induced under these specific conditions. In experimental studies, abrupt nutrient changes are often used to induce autophagy. In this study, we investigated autophagy induction in batch culture on low-glucose medium, in which growth of yeast (Saccharomyces cerevisiae) cells is clearly reflected exclusively by carbon source state. In this medium, cells pass sequentially through three stages: glucose-utilizing, ethanol-utilizing, and ethanol-depleted phases. Using GFP cleavage assay by immunoblotting methods, fluorescence microscopy, and transmission electron microscopy ultrastructural analysis, we found that bulk autophagy and endoplasmic reticulum-phagy are induced starting at the ethanol-utilizing phase, and bulk autophagy is activated to a greater extent in the ethanol-depleted phase. Furthermore, we found that mitophagy is induced by ethanol depletion. Microautophagy occurred after glucose depletion and involved incorporation of cytosolic components and lipid droplets into the vacuolar lumen. Moreover, we observed that autophagy-deficient cells grow more slowly in the ethanol-utilizing phase and exhibit a delay in growth resumption when they are shifted to fresh medium from the ethanol-depleted phase. Our findings suggest that distinct types of autophagy are induced in yeast cells undergoing gradual changes in carbon source availability.
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Affiliation(s)
- Ryo Iwama
- From the Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-12 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Yoshinori Ohsumi
- From the Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-12 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
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29
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Parzych KR, Klionsky DJ. Vacuolar hydrolysis and efflux: current knowledge and unanswered questions. Autophagy 2018; 15:212-227. [PMID: 30422029 DOI: 10.1080/15548627.2018.1545821] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Hydrolysis within the vacuole in yeast and the lysosome in mammals is required for the degradation and recycling of a multitude of substrates, many of which are delivered to the vacuole/lysosome by autophagy. In humans, defects in lysosomal hydrolysis and efflux can have devastating consequences, and contribute to a class of diseases referred to as lysosomal storage disorders. Despite the importance of these processes, many of the proteins and regulatory mechanisms involved in hydrolysis and efflux are poorly understood. In this review, we describe our current knowledge of the vacuolar/lysosomal degradation and efflux of a vast array of substrates, focusing primarily on what is known in the yeast Saccharomyces cerevisiae. We also highlight many unanswered questions, the answers to which may lead to new advances in the treatment of lysosomal storage disorders. Abbreviations: Ams1: α-mannosidase; Ape1: aminopeptidase I; Ape3: aminopeptidase Y; Ape4: aspartyl aminopeptidase; Atg: autophagy related; Cps1: carboxypeptidase S; CTNS: cystinosin, lysosomal cystine transporter; CTSA: cathepsin A; CTSD: cathepsin D; Cvt: cytoplasm-to-vacuole targeting; Dap2: dipeptidyl aminopeptidase B; GS-bimane: glutathione-S-bimane; GSH: glutathione; LDs: lipid droplets; MVB: multivesicular body; PAS: phagophore assembly site; Pep4: proteinase A; PolyP: polyphosphate; Prb1: proteinase B; Prc1: carboxypeptidase Y; V-ATPase: vacuolar-type proton-translocating ATPase; VTC: vacuolar transporter chaperone.
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Affiliation(s)
- Katherine R Parzych
- a Life Sciences Institute, and Department of Molecular, Cellular and Developmental Biology , University of Michigan , Ann Arbor , MI , USA
| | - Daniel J Klionsky
- a Life Sciences Institute, and Department of Molecular, Cellular and Developmental Biology , University of Michigan , Ann Arbor , MI , USA
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30
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Yue W, Nie X, Cui L, Zhi Y, Zhang T, Du X, Song W. Genome-wide sequence and expressional analysis of autophagy Gene family in bread wheat (Triticum aestivum L.). JOURNAL OF PLANT PHYSIOLOGY 2018; 229:7-21. [PMID: 30025220 DOI: 10.1016/j.jplph.2018.06.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 05/06/2023]
Abstract
Autophagy, a highly conserved intracellular degradation system, is regarded to be responsible for self-defense and protect cells from abiotic stress. Extensive studies have demonstrated that autophagy plays a crucial role in regulating plant growth and development as well as in response to diverse stresses. However, little is known about autophagy-associated genes (ATGs) in wheat, especially those involved in the regulatory network of stress processes. In this study, a total of 108 putative wheat ATGs (TaATG) were obtained based on a genome-wide search approach. Phylogenetic analysis classified them into 13 subfamilies, of which the TaAtg16 subfamily consisted of 29 members, ranking it the largest subfamily. The conserved motif compositions as well as their exon-intron structures were systematically analyzed and strongly supported the classification. The homoeologous genes tended to have similar gene features during wheat polyploidization. Furthermore, a total of 114 putative cis-elements were found, and those related to hormone, stress, and light responsiveness were abundantly presented in the promoter regions. Co-expression network analysis revealed that orthologous VAMP727 was the hub node of the whole network, and complex interactions were also found. Finally, the expression profiles of TaATGs among different tissues and under abiotic stresses were investigated to identify tissue-specific or stress-responsive candidates, and then 14 were validated by wet-lab analysis. Results showed that the TaAtg8 subfamily played a crucial role in tissue autophagy and stress defense, which could be considered as processes that are candidates for further functional study. This was the first study to comprehensively investigate the ATG family in wheat, which ultimately provided important clues for further functional analysis and also took a step toward uncovering the evolutionary mechanism of ATG genes in wheat and beyond.
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Affiliation(s)
- Wenjie Yue
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling, Shaanxi, China.
| | - Xiaojun Nie
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling, Shaanxi, China.
| | - Licao Cui
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling, Shaanxi, China.
| | - Yongqiang Zhi
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling, Shaanxi, China.
| | - Ting Zhang
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling, Shaanxi, China.
| | - Xianghong Du
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling, Shaanxi, China.
| | - Weining Song
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling, Shaanxi, China; Australia-China Joint Research Centre for Abiotic and Biotic Stress Management in Agriculture, Horticulture and Forestry, Northwest A&F University, Yangling, Shaanxi, China.
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31
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Ding JL, Peng YJ, Chu XL, Feng MG, Ying SH. Autophagy-related gene BbATG11 is indispensable for pexophagy and mitophagy, and contributes to stress response, conidiation and virulence in the insect mycopathogen Beauveria bassiana. Environ Microbiol 2018; 20:3309-3324. [PMID: 30058280 DOI: 10.1111/1462-2920.14329] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/06/2018] [Accepted: 06/17/2018] [Indexed: 12/17/2022]
Abstract
Autophagy is a conserved degradation system in eukaryotic cells that includes non-selective and selective processes. Selective autophagy functions as a selective degradation mechanism for specific substrates in which autophagy-related protein 11 (ATG11) acts as an essential scaffold protein. In B. bassiana, there is a unique ATG11 family protein, which is designated as BbATG11. Disruption of BbATG11 resulted in significantly reduced conidial germination under starvation stress. The mutant ΔBbATG11 displayed enhanced sensitivity to oxidative stress and impaired asexual reproduction. The conidial yield was reduced by approximately 75%, and this defective phenotype could be repressed by increasing exogenous nutrients. The virulence of the ΔBbATG11 mutant strain was significantly impaired as indicated in topical and intra-hemocoel injection bioassays, with a greater reduction in topical infection. Notably, BbATG11 was involved in pexophagy and mitophagy, but these two autophagic processes appeared in different fungal physiological aspects. Both pexophagy and mitophagy were associated with nutrient shift, starvation stress and growth in the host hemocoel, but only pexophagy appeared in both oxidation-stressed cells and aerial mycelia. This study highlights that BbATG11 mediates pexophagy and mitophagy in B. bassiana and links selective autophagy to the fungal stress response, conidiation and virulence.
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Affiliation(s)
- Jin-Li Ding
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yue-Jin Peng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xin-Ling Chu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
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32
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Brown RB, Razzaque MS. Phosphate toxicity and tumorigenesis. Biochim Biophys Acta Rev Cancer 2018; 1869:303-309. [PMID: 29684520 DOI: 10.1016/j.bbcan.2018.04.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/17/2018] [Accepted: 04/18/2018] [Indexed: 02/07/2023]
Abstract
In this article, we briefly summarized evidence that cellular phosphate burden from phosphate toxicity is a pathophysiological determinant of cancer cell growth. Tumor cells express more phosphate cotransporters and store more inorganic phosphate than normal cells, and dysregulated phosphate homeostasis is associated with the genesis of various human tumors. High dietary phosphate consumption causes the growth of lung and skin tumors in experimental animal models. Additional studies show that excessive phosphate burden induces growth-promoting cell signaling, stimulates neovascularization, and is associated with chromosome instability and metastasis. Studies have also shown phosphate is a mitogenic factor that affects various tumor cell growth. Among epidemiological evidence linking phosphate and tumor formation, the Health Professionals Follow-Up Study found that high dietary phosphate levels were independently associated with lethal and high-grade prostate cancer. Further research is needed to determine how excessive dietary phosphate consumption influences initiation and promotion of tumorigenesis, and to elucidate prognostic benefits of reducing phosphate burden to decrease tumor cell growth and delay metastatic progression. The results of such studies could provide the basis for therapeutic modulation of phosphate metabolism for improved patient outcome.
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Affiliation(s)
- Ronald B Brown
- School of Public Health & Health Systems, University of Waterloo, Waterloo, Ontario, Canada
| | - Mohammed S Razzaque
- Department of Oral Health Policy & Epidemiology, Harvard School of Dental Medicine, Boston, MA, USA; Department of Preventive & Community Dentistry, University of Rwanda College of Medicine & Health Sciences, School of Dentistry, Kigali, Rwanda; Department of Pathology, Lake Erie College of Osteopathic Medicine, Erie, PA, USA.
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33
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Umekawa M, Ujihara M, Nakai D, Takematsu H, Wakayama M. Ecm33 is a novel factor involved in efficient glucose uptake for nutrition-responsive TORC1 signaling in yeast. FEBS Lett 2017; 591:3721-3729. [PMID: 29029364 DOI: 10.1002/1873-3468.12882] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 11/09/2022]
Abstract
Glucose uptake is crucial for providing both an energy source and a signal that regulates cell proliferation. Therefore, it is important to clarify the mechanisms underlying glucose uptake and its transmission to intracellular signaling pathways. In this study, we searched for a novel regulatory factor involved in glucose-induced signaling by using Saccharomyces cerevisiae as a eukaryotic model. Requirement of the extracellular protein Ecm33 in efficient glucose uptake and full activation of the nutrient-responsive TOR kinase complex 1 (TORC1) signaling pathway is shown. Cells lacking Ecm33 elicit a series of starvation-induced pathways even in the presence of extracellular high glucose concentration. This results in delayed cell proliferation, reduced ATP, induction of autophagy, and dephosphorylation of the TORC1 substrates Atg13 and Sch9.
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Affiliation(s)
| | - Masato Ujihara
- Faculty of Life Sciences, Ritsumeikan University, Kyoto, Shiga, Japan
| | - Daiki Nakai
- Faculty of Life Sciences, Ritsumeikan University, Kyoto, Shiga, Japan
| | | | - Mamoru Wakayama
- Faculty of Life Sciences, Ritsumeikan University, Kyoto, Shiga, Japan
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34
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Adachi A, Koizumi M, Ohsumi Y. Autophagy induction under carbon starvation conditions is negatively regulated by carbon catabolite repression. J Biol Chem 2017; 292:19905-19918. [PMID: 29042435 DOI: 10.1074/jbc.m117.817510] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/10/2017] [Indexed: 12/30/2022] Open
Abstract
Autophagy is a conserved process in which cytoplasmic components are sequestered for degradation in the vacuole/lysosomes in eukaryotic cells. Autophagy is induced under a variety of starvation conditions, such as the depletion of nitrogen, carbon, phosphorus, zinc, and others. However, apart from nitrogen starvation, it remains unclear how these stimuli induce autophagy. In yeast, for example, it remains contentious whether autophagy is induced under carbon starvation conditions, with reports variously suggesting both induction and lack of induction upon depletion of carbon. We therefore undertook an analysis to account for these inconsistencies, concluding that autophagy is induced in response to abrupt carbon starvation when cells are grown with glycerol but not glucose as the carbon source. We found that autophagy under these conditions is mediated by nonselective degradation that is highly dependent on the autophagosome-associated scaffold proteins Atg11 and Atg17. We also found that the extent of carbon starvation-induced autophagy is positively correlated with cells' oxygen consumption rate, drawing a link between autophagy induction and respiratory metabolism. Further biochemical analyses indicated that maintenance of intracellular ATP levels is also required for carbon starvation-induced autophagy and that autophagy plays an important role in cell viability during prolonged carbon starvation. Our findings suggest that carbon starvation-induced autophagy is negatively regulated by carbon catabolite repression.
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Affiliation(s)
- Atsuhiro Adachi
- From the Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-12 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Michiko Koizumi
- From the Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-12 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Yoshinori Ohsumi
- From the Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4259-S2-12 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
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