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Prigent M, Jean-Jacques H, Naquin D, Chédin S, Cuif MH, Legouis R, Kuras L. Sulfur starvation-induced autophagy in Saccharomyces cerevisiae involves SAM-dependent signaling and transcription activator Met4. Nat Commun 2024; 15:6927. [PMID: 39138175 DOI: 10.1038/s41467-024-51309-6] [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: 05/03/2022] [Accepted: 08/01/2024] [Indexed: 08/15/2024] Open
Abstract
Autophagy is a key lysosomal degradative mechanism allowing a prosurvival response to stresses, especially nutrient starvation. Here we investigate the mechanism of autophagy induction in response to sulfur starvation in Saccharomyces cerevisiae. We found that sulfur deprivation leads to rapid and widespread transcriptional induction of autophagy-related (ATG) genes in ways not seen under nitrogen starvation. This distinctive response depends mainly on the transcription activator of sulfur metabolism Met4. Consistently, Met4 is essential for autophagy under sulfur starvation. Depletion of either cysteine, methionine or SAM induces autophagy flux. However, only SAM depletion can trigger strong transcriptional induction of ATG genes and a fully functional autophagic response. Furthermore, combined inactivation of Met4 and Atg1 causes a dramatic decrease in cell survival under sulfur starvation, highlighting the interplay between sulfur metabolism and autophagy to maintain cell viability. Thus, we describe a pathway of sulfur starvation-induced autophagy depending on Met4 and involving SAM as signaling sulfur metabolite.
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Affiliation(s)
- Magali Prigent
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- INSERM U1280, 91198, Gif-sur-Yvette, France
| | - Hélène Jean-Jacques
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Delphine Naquin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Stéphane Chédin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Marie-Hélène Cuif
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- INSERM U1280, 91198, Gif-sur-Yvette, France
| | - Renaud Legouis
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- INSERM U1280, 91198, Gif-sur-Yvette, France
| | - Laurent Kuras
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France.
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2
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Bueno-Arribas M, Cruz-Cuevas C, Navas MA, Escalante R, Vincent O. Coiled-coil-mediated dimerization of Atg16 is required for binding to the PROPPIN Atg21. Open Biol 2023; 13:230192. [PMID: 37989223 PMCID: PMC10688262 DOI: 10.1098/rsob.230192] [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: 06/22/2023] [Accepted: 10/13/2023] [Indexed: 11/23/2023] Open
Abstract
PROPPINs/WIPIs are β-propeller proteins that bind phosphoinositides and contribute to the recruitment of protein complexes involved in membrane remodelling processes such as autophagosome formation and endosomal trafficking. Yeast Atg21 and mammalian WIPI2 interact with Atg16/ATG16L1 to mediate recruitment of the lipidation machinery to the autophagosomal membrane. Here, we used the reverse double two-hybrid method (RD2H) to identify residues in Atg21 and Atg16 critical for protein-protein binding. Although our results are generally consistent with the crystal structure of the Atg21-Atg16 complex reported previously, they also reveal that dimerization of the Atg16 coiled-coil domain is required for Atg21 binding. Furthermore, most of the residues identified in Atg21 are conserved in WIPI2 and we showed that these residues also mediate ATG16L1 binding. Strikingly, these residues occupy the same position in the β-propeller structure as residues in PROPPINs/WIPIs Hsv2 and WIPI4 that mediate Atg2/ATG2A binding, supporting the idea that these proteins use different amino acids at the same position to interact with different autophagic proteins. Finally, our findings demonstrate the effectiveness of the RD2H system to identify critical residues for protein-protein interactions and the utility of this method to generate combinatory mutants with a complete loss of binding capacity.
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Affiliation(s)
- Miranda Bueno-Arribas
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
| | - Celia Cruz-Cuevas
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
| | - María-Angeles Navas
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Ricardo Escalante
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
| | - Olivier Vincent
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
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3
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Liu S, Chen M, Wang Y, Lei Y, Huang T, Zhang Y, Lam SM, Li H, Qi S, Geng J, Lu K. The ER calcium channel Csg2 integrates sphingolipid metabolism with autophagy. Nat Commun 2023; 14:3725. [PMID: 37349354 PMCID: PMC10287731 DOI: 10.1038/s41467-023-39482-6] [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: 06/29/2022] [Accepted: 06/15/2023] [Indexed: 06/24/2023] Open
Abstract
Sphingolipids are ubiquitous components of membranes and function as bioactive lipid signaling molecules. Here, through genetic screening and lipidomics analyses, we find that the endoplasmic reticulum (ER) calcium channel Csg2 integrates sphingolipid metabolism with autophagy by regulating ER calcium homeostasis in the yeast Saccharomyces cerevisiae. Csg2 functions as a calcium release channel and maintains calcium homeostasis in the ER, which enables normal functioning of the essential sphingolipid synthase Aur1. Under starvation conditions, deletion of Csg2 causes increases in calcium levels in the ER and then disturbs Aur1 stability, leading to accumulation of the bioactive sphingolipid phytosphingosine, which specifically and completely blocks autophagy and induces loss of starvation resistance in cells. Our findings indicate that calcium homeostasis in the ER mediated by the channel Csg2 translates sphingolipid metabolism into autophagy regulation, further supporting the role of the ER as a signaling hub for calcium homeostasis, sphingolipid metabolism and autophagy.
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Affiliation(s)
- Shiyan Liu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Mutian Chen
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy, Med-X Center for Manufacturing, West China Hospital, Sichuan University, Chengdu, 610041, China
- Tianfu Jincheng Laboratory, City of Future Medicine, Chengdu, 641400, China
| | - Yichang Wang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yuqing Lei
- Department of Pathology, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Ting Huang
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yabin Zhang
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- LipidALL Technologies Company Limited, Changzhou, 213022, China
| | - Huihui Li
- Department of Pathology, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
| | - Shiqian Qi
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Jia Geng
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy, Med-X Center for Manufacturing, West China Hospital, Sichuan University, Chengdu, 610041, China.
- Tianfu Jincheng Laboratory, City of Future Medicine, Chengdu, 641400, China.
| | - Kefeng Lu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
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4
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Garrido-Huarte JL, Fita-Torró J, Viana R, Pascual-Ahuir A, Proft M. Severe acute respiratory syndrome coronavirus-2 accessory proteins ORF3a and ORF7a modulate autophagic flux and Ca2+ homeostasis in yeast. Front Microbiol 2023; 14:1152249. [PMID: 37077240 PMCID: PMC10106705 DOI: 10.3389/fmicb.2023.1152249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/21/2023] [Indexed: 04/05/2023] Open
Abstract
Virus infection involves the manipulation of key host cell functions by specialized virulence proteins. The Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) small accessory proteins ORF3a and ORF7a have been implicated in favoring virus replication and spreading by inhibiting the autophagic flux within the host cell. Here, we apply yeast models to gain insights into the physiological functions of both SARS-CoV-2 small open reading frames (ORFs). ORF3a and ORF7a can be stably overexpressed in yeast cells, producing a decrease in cellular fitness. Both proteins show a distinguishable intracellular localization. ORF3a localizes to the vacuolar membrane, whereas ORF7a targets the endoplasmic reticulum. Overexpression of ORF3a and ORF7a leads to the accumulation of Atg8 specific autophagosomes. However, the underlying mechanism is different for each viral protein as assessed by the quantification of the autophagic degradation of Atg8-GFP fusion proteins, which is inhibited by ORF3a and stimulated by ORF7a. Overexpression of both SARS-CoV-2 ORFs decreases cellular fitness upon starvation conditions, where autophagic processes become essential. These data confirm previous findings on SARS-CoV-2 ORF3a and ORF7a manipulating autophagic flux in mammalian cell models and are in agreement with a model where both small ORFs have synergistic functions in stimulating intracellular autophagosome accumulation, ORF3a by inhibiting autophagosome processing at the vacuole and ORF7a by promoting autophagosome formation at the ER. ORF3a has an additional function in Ca2+ homeostasis. The overexpression of ORF3a confers calcineurin-dependent Ca2+ tolerance and activates a Ca2+ sensitive FKS2-luciferase reporter, suggesting a possible ORF3a-mediated Ca2+ efflux from the vacuole. Taken together, we show that viral accessory proteins can be functionally investigated in yeast cells and that SARS-CoV-2 ORF3a and ORF7a proteins interfere with autophagosome formation and processing as well as with Ca2+ homeostasis from distinct cellular targets.
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Affiliation(s)
- José Luis Garrido-Huarte
- Department of Molecular and Cellular Pathology and Therapy, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Josep Fita-Torró
- Department of Molecular and Cellular Pathology and Therapy, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Rosa Viana
- Department of Molecular and Cellular Pathology and Therapy, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Amparo Pascual-Ahuir
- Department of Biotechnology, Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València UPV, Valencia, Spain
- *Correspondence: Amparo Pascual-Ahuir,
| | - Markus Proft
- Department of Molecular and Cellular Pathology and Therapy, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
- Markus Proft,
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5
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Huang T, Jiang G, Zhang Y, Lei Y, Liu S, Li H, Lu K. The RNA polymerase II subunit Rpb9 activates ATG1 transcription and autophagy. EMBO Rep 2022; 23:e54993. [PMID: 36102592 PMCID: PMC9638876 DOI: 10.15252/embr.202254993] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 08/23/2022] [Accepted: 08/26/2022] [Indexed: 08/01/2023] Open
Abstract
Macroautophagy/autophagy is a conserved process in eukaryotic cells that mediates the degradation and recycling of intracellular substrates. Proteins encoded by autophagy-related (ATG) genes are essentially involved in the autophagy process and must be tightly regulated in response to various circumstances, such as nutrient-rich and starvation conditions. However, crucial transcriptional activators of ATG genes have remained obscure. Here, we identify the RNA polymerase II subunit Rpb9 as an essential regulator of autophagy by a high-throughput screen of a Saccharomyces cerevisiae gene knockout library. Rpb9 plays a crucial and specific role in upregulating ATG1 transcription, and its deficiency decreases autophagic activities. Rpb9 promotes ATG1 transcription by binding to its promoter region, which is mediated by Gcn4. Furthermore, the function of Rpb9 in autophagy and its regulation of ATG1/ULK1 transcription are conserved in mammalian cells. Together, our results indicate that Rpb9 specifically activates ATG1 transcription and thus positively regulates the autophagy process.
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Affiliation(s)
- Ting Huang
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Gaoyue Jiang
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Yabin Zhang
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Yuqing Lei
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Shiyan Liu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
| | - Huihui Li
- West China Second University HospitalSichuan UniversityChengduChina
| | - Kefeng Lu
- Department of Neurosurgery, State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduChina
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6
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Kira S, Noguchi M, Araki Y, Oikawa Y, Yoshimori T, Miyahara A, Noda T. Vacuolar protein Tag1 and Atg1-Atg13 regulate autophagy termination during persistent starvation in S. cerevisiae. J Cell Sci 2021; 134:jcs.253682. [PMID: 33536246 DOI: 10.1242/jcs.253682] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/19/2021] [Indexed: 02/06/2023] Open
Abstract
Under starvation conditions, cells degrade their own components via autophagy in order to provide sufficient nutrients to ensure their survival. However, even if starvation persists, the cell is not completely degraded through autophagy, implying the existence of some kind of termination mechanism. In the yeast Saccharomyces cerevisiae, autophagy is terminated after 10-12 h of nitrogen starvation. In this study, we found that termination is mediated by re-phosphorylation of Atg13 by the Atg1 protein kinase, which is also affected by PP2C phosphatases, and the eventual dispersion of the pre-autophagosomal structure, also known as the phagophore assembly site (PAS). In a genetic screen, we identified an uncharacterized vacuolar membrane protein, Tag1, as a factor responsible for the termination of autophagy. Re-phosphorylation of Atg13 and eventual PAS dispersal were defective in the Δtag1 mutant. The vacuolar luminal domain of Tag1 and autophagic progression are important for the behaviors of Tag1. Together, our findings reveal the mechanism and factors responsible for termination of autophagy in yeast.
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Affiliation(s)
- Shintaro Kira
- Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Yamadaoka 1-8, Suita, Osaka 565-0871, Japan
| | - Masafumi Noguchi
- Department of Oral Frontier Biology, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-8, Suita, Osaka 565-0871, Japan.,Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan
| | - Yasuhiro Araki
- Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Yamadaoka 1-8, Suita, Osaka 565-0871, Japan
| | - Yu Oikawa
- Research Center of Cell Biology, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259, Yokohama, Kanagawa 226-8503, Japan
| | - Tamotsu Yoshimori
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan.,Department of Genetics, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan
| | - Aiko Miyahara
- Department of Oral Frontier Biology, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-8, Suita, Osaka 565-0871, Japan.,Department of Genetics, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan
| | - Takeshi Noda
- Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Yamadaoka 1-8, Suita, Osaka 565-0871, Japan .,Department of Oral Frontier Biology, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-8, Suita, Osaka 565-0871, Japan
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7
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Characterization of constitutive ER-phagy of excess membrane proteins. PLoS Genet 2020; 16:e1009255. [PMID: 33275594 PMCID: PMC7744050 DOI: 10.1371/journal.pgen.1009255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 12/16/2020] [Accepted: 11/05/2020] [Indexed: 11/19/2022] Open
Abstract
Thirty percent of all cellular proteins are inserted into the endoplasmic reticulum (ER), which spans throughout the cytoplasm. Two well-established stress-induced pathways ensure quality control (QC) at the ER: ER-phagy and ER-associated degradation (ERAD), which shuttle cargo for degradation to the lysosome and proteasome, respectively. In contrast, not much is known about constitutive ER-phagy. We have previously reported that excess of integral-membrane proteins is delivered from the ER to the lysosome via autophagy during normal growth of yeast cells. Whereas endogenously expressed ER resident proteins serve as cargos at a basal level, this level can be induced by overexpression of membrane proteins that are not ER residents. Here, we characterize this pathway as constitutive ER-phagy. Constitutive and stress-induced ER-phagy share the basic macro-autophagy machinery including the conserved Atgs and Ypt1 GTPase. However, induction of stress-induced autophagy is not needed for constitutive ER-phagy to occur. Moreover, the selective receptors needed for starvation-induced ER-phagy, Atg39 and Atg40, are not required for constitutive ER-phagy and neither these receptors nor their cargos are delivered through it to the vacuole. As for ERAD, while constitutive ER-phagy recognizes cargo different from that recognized by ERAD, these two ER-QC pathways can partially substitute for each other. Because accumulation of membrane proteins is associated with disease, and constitutive ER-phagy players are conserved from yeast to mammalian cells, this process could be critical for human health.
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8
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Wu C, Yao W, Kai W, Liu W, Wang W, Li S, Chen Y, Wu X, Wang L, Li Y, Tong J, Qian J, Zhang L, Hong Z, Yi C. Mitochondrial Fusion Machinery Specifically Involved in Energy Deprivation-Induced Autophagy. Front Cell Dev Biol 2020; 8:221. [PMID: 32318571 PMCID: PMC7154291 DOI: 10.3389/fcell.2020.00221] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/16/2020] [Indexed: 01/03/2023] Open
Abstract
Mitochondria are highly dynamic organelles, which can form a network in cells through fusion, fission, and tubulation. Its morphology is closely related to the function of mitochondria. The damaged mitochondria can be removed by mitophagy. However, the relationship between mitochondrial morphology and non-selective autophagy is not fully understood. We found that mitochondrial fusion machinery, not fission or tubulation machinery, is essential for energy deprivation-induced autophagy. In response to glucose starvation, deletion of mitochondrial fusion proteins severely impaired the association of Atg1/ULK1 with Atg13, and then affected the recruitment of Atg1 and other autophagic proteins to PAS (phagophore assembly site). Furthermore, the deletion of fusion proteins blocks mitochondrial respiration, the binding of Snf1-Mec1, the phosphorylation of Mec1 by Snf1, and the dissociation of Mec1 from mitochondria under prolonged starvation. We propose that mitochondrial fusion machinery regulates energy deprivation-induced autophagy through maintaining mitochondrial respiration.
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Affiliation(s)
- Choufei Wu
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University, Huzhou, China
| | - Weijing Yao
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenwen Kai
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University, Huzhou, China
| | - Weikang Liu
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenlve Wang
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shuzhen Li
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yingcong Chen
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoyong Wu
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Liefeng Wang
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, Ganzhou, China
| | - Ying Li
- School of Life Sciences, Tsinghua University-Peking University Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | - Jingjing Tong
- School of Life Sciences, Central China Normal University, Wuhan, China
| | - Jing Qian
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Nursing and Medicine, Huzhou University, Huzhou, China
| | - Liqin Zhang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University, Huzhou, China
| | - Zhi Hong
- Department of Breast Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China.,ZJU-UoE Institute, Zhejiang University School of Medicine, International Campus, Zhejiang University, Haining, China
| | - Cong Yi
- Department of Biochemistry, Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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9
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Rpn4 and proteasome-mediated yeast resistance to ethanol includes regulation of autophagy. Appl Microbiol Biotechnol 2020; 104:4027-4041. [PMID: 32157425 DOI: 10.1007/s00253-020-10518-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/15/2020] [Accepted: 03/01/2020] [Indexed: 12/18/2022]
Abstract
Distilled spirits production using Saccharomyces cerevisiae requires understanding of the mechanisms of yeast cell response to alcohol stress. Reportedly, specific mutations in genes of the ubiquitin-proteasome system, e.g., RPN4, may result in strains exhibiting hyper-resistance to different alcohols. To study the Rpn4-dependent yeast response to short-term ethanol exposure, we performed a comparative analysis of the wild-type (WT) strain, strain with RPN4 gene deletion (rpn4-Δ), and a mutant strain with decreased proteasome activity and consequent Rpn4 accumulation due to PRE1 deregulation (YPL). The stress resistance tests demonstrated an increased sensitivity of mutant strains to ethanol compared with WT. Comparative proteomics analysis revealed significant differences in molecular responses to ethanol between these strains. GO analysis of proteins upregulated in WT showed enrichments represented by oxidative and heat responses, protein folding/unfolding, and protein degradation. Enrichment of at least one of these responses was not observed in the mutant strains. Moreover, activity of autophagy was not increased in the RPN4 deletion strain upon ethanol stress which agrees with changes in mRNA levels of ATG7 and PRB1 genes of the autophagy system. Activity of the autophagic system was clearly induced and accompanied with PRB1 overexpression in the YPL strain upon ethanol stress. We demonstrated that Rpn4 stabilization contributes to the PRB1 upregulation. CRISPR-Cas9-mediated repression of PACE-core Rpn4 binding sites in the PRB1 promoter inhibits PRB1 induction in the YPL strain upon ethanol treatment and results in YPL hypersensitivity to ethanol. Our data suggest that Rpn4 affects the autophagic system activity upon ethanol stress through the PRB1 regulation. These findings can be a basis for creating genetically modified yeast strains resistant to high levels of alcohol, being further used for fermentation in ethanol production.
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10
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Torggler R, Papinski D, Kraft C. Assays to Monitor Autophagy in Saccharomyces cerevisiae. Cells 2017; 6:cells6030023. [PMID: 28703742 PMCID: PMC5617969 DOI: 10.3390/cells6030023] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/04/2017] [Accepted: 07/09/2017] [Indexed: 12/18/2022] Open
Abstract
Autophagy is an intracellular process responsible for the degradation and recycling of cytoplasmic components. It selectively removes harmful cellular material and enables the cell to survive starvation by mobilizing nutrients via the bulk degradation of cytoplasmic components. While research over the last decades has led to the discovery of the key factors involved in autophagy, the pathway is not yet completely understood. The first studies of autophagy on a molecular level were conducted in the yeast Saccharomyces cerevisiae. Building up on these studies, many homologs have been found in higher eukaryotes. Yeast remains a highly relevant model organism for studying autophagy, with a wide range of established methods to elucidate the molecular details of the autophagy pathway. In this review, we provide an overview of methods to study both selective and bulk autophagy, including intermediate steps in the yeast Saccharomyces cerevisiae. We compare different assays, discuss their advantages and limitations and list potential applications.
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Affiliation(s)
- Raffaela Torggler
- Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, 1030 Vienna, Austria
| | - Daniel Papinski
- Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, 1030 Vienna, Austria.
| | - Claudine Kraft
- Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, 1030 Vienna, Austria.
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