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Filali-Mouncef Y, Leytens A, Vargas Duarte P, Zampieri M, Dengjel J, Reggiori F. An APEX2-based proximity-dependent biotinylation assay with temporal specificity to study protein interactions during autophagy in the yeast Saccharomyces cerevisiae. Autophagy 2024:1-16. [PMID: 38958087 DOI: 10.1080/15548627.2024.2366749] [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: 12/03/2023] [Accepted: 06/07/2024] [Indexed: 07/04/2024] Open
Abstract
Autophagosome biogenesis is a complex process orchestrated by dynamic interactions between Atg (autophagy-related) proteins and characterized by the turnover of specific cargoes, which can differ over time and depending on how autophagy is stimulated. Proteomic analyses are central to uncover protein-protein interaction networks and when combined with proximity-dependent biotinylation or proximity labeling (PL) approaches, they also permit to detect transient and weak interactions. However, current PL procedures for yeast Saccharomyces cerevisiae, one of the leading models for the study of autophagy, do not allow to keep temporal specificity and thus identify interactions and cargoes at a precise time point upon autophagy induction. Here, we present a new ascorbate peroxidase 2 (APEX2)-based PL protocol adapted to yeast that preserves temporal specificity and allows uncovering neighbor proteins by either western blot or proteomics. As a proof of concept, we applied this new method to identify Atg8 and Atg9 interactors and detected known binding partners as well as potential uncharacterized ones in rich and nitrogen starvation conditions. Also, as a proof of concept, we confirmed the spatial proximity interaction between Atg8 and Faa1. We believe that this protocol will be a new important experimental tool for all those researchers studying the mechanism and roles of autophagy in yeast, but also other cellular pathways in this model organism.Abbreviations: APEX2, ascorbate peroxidase 2, Atg, autophagy-related; BP, biotin phenol; Cvt, cytoplasm-to-vacuole targeting; ER, endoplasmic reticulum; LN2, liquid nitrogen; MS, mass spectrometry; PAS, phagophore assembly site; PL, proximity labeling; PE, phosphatidylethanolamine; PPINs, protein-protein interaction networks; PPIs, protein-protein interactions; RT, room temperature; SARs, selective autophagy receptors; WT, wild-type.
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Affiliation(s)
- Yasmina Filali-Mouncef
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, AV, The Netherlands
| | - Alexandre Leytens
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | - Mattia Zampieri
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, AV, The Netherlands
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus C, Denmark
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2
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Chakraborty S, Nandi P, Mishra J, Niharika, Roy A, Manna S, Baral T, Mishra P, Mishra PK, Patra SK. Molecular mechanisms in regulation of autophagy and apoptosis in view of epigenetic regulation of genes and involvement of liquid-liquid phase separation. Cancer Lett 2024; 587:216779. [PMID: 38458592 DOI: 10.1016/j.canlet.2024.216779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/19/2024] [Accepted: 02/29/2024] [Indexed: 03/10/2024]
Abstract
Cellular physiology is critically regulated by multiple signaling nexuses, among which cell death mechanisms play crucial roles in controlling the homeostatic landscape at the tissue level within an organism. Apoptosis, also known as programmed cell death, can be induced by external and internal stimuli directing the cells to commit suicide in unfavourable conditions. In contrast, stress conditions like nutrient deprivation, infection and hypoxia trigger autophagy, which is lysosome-mediated processing of damaged cellular organelle for recycling of the degraded products, including amino acids. Apparently, apoptosis and autophagy both are catabolic and tumor-suppressive pathways; apoptosis is essential during development and cancer cell death, while autophagy promotes cell survival under stress. Moreover, autophagy plays dual role during cancer development and progression by facilitating the survival of cancer cells under stressed conditions and inducing death in extreme adversity. Despite having two different molecular mechanisms, both apoptosis and autophagy are interconnected by several crosslinking intermediates. Epigenetic modifications, such as DNA methylation, post-translational modification of histone tails, and miRNA play a pivotal role in regulating genes involved in both autophagy and apoptosis. Both autophagic and apoptotic genes can undergo various epigenetic modifications and promote or inhibit these processes under normal and cancerous conditions. Epigenetic modifiers are uniquely important in controlling the signaling pathways regulating autophagy and apoptosis. Therefore, these epigenetic modifiers of both autophagic and apoptotic genes can act as novel therapeutic targets against cancers. Additionally, liquid-liquid phase separation (LLPS) also modulates the aggregation of misfolded proteins and provokes autophagy in the cytosolic environment. This review deals with the molecular mechanisms of both autophagy and apoptosis including crosstalk between them; emphasizing epigenetic regulation, involvement of LLPS therein, and possible therapeutic approaches against cancers.
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Affiliation(s)
- Subhajit Chakraborty
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Piyasa Nandi
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Jagdish Mishra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Niharika
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Ankan Roy
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Soumen Manna
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Tirthankar Baral
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Prahallad Mishra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Pradyumna Kumar Mishra
- Department of Molecular Biology, ICMR-National Institute for Research in Environmental Health, Bypass Road, Bhauri, Bhopal, 462 030, MP, India
| | - Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India.
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Schmid M, Fischer P, Engl M, Widder J, Kerschbaum-Gruber S, Slade D. The interplay between autophagy and cGAS-STING signaling and its implications for cancer. Front Immunol 2024; 15:1356369. [PMID: 38660307 PMCID: PMC11039819 DOI: 10.3389/fimmu.2024.1356369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
Autophagy is an intracellular process that targets various cargos for degradation, including members of the cGAS-STING signaling cascade. cGAS-STING senses cytosolic double-stranded DNA and triggers an innate immune response through type I interferons. Emerging evidence suggests that autophagy plays a crucial role in regulating and fine-tuning cGAS-STING signaling. Reciprocally, cGAS-STING pathway members can actively induce canonical as well as various non-canonical forms of autophagy, establishing a regulatory network of feedback mechanisms that alter both the cGAS-STING and the autophagic pathway. The crosstalk between autophagy and the cGAS-STING pathway impacts a wide variety of cellular processes such as protection against pathogenic infections as well as signaling in neurodegenerative disease, autoinflammatory disease and cancer. Here we provide a comprehensive overview of the mechanisms involved in autophagy and cGAS-STING signaling, with a specific focus on the interactions between the two pathways and their importance for cancer.
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Affiliation(s)
- Maximilian Schmid
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
| | - Patrick Fischer
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
| | - Magdalena Engl
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Joachim Widder
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Sylvia Kerschbaum-Gruber
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
| | - Dea Slade
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
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4
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Pareek G, Kundu M. Physiological functions of ULK1/2. J Mol Biol 2024:168472. [PMID: 38311233 DOI: 10.1016/j.jmb.2024.168472] [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: 12/19/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/10/2024]
Abstract
UNC-51-like kinases 1 and 2 (ULK1/2) are serine/threonine kinases that are best known for their evolutionarily conserved role in the autophagy pathway. Upon sensing the nutrient status of a cell, ULK1/2 integrate signals from upstream cellular energy sensors such as mTOR and AMPK and relay them to the downstream components of the autophagy machinery. ULK1/2 also play indispensable roles in the selective autophagy pathway, removing damaged mitochondria, invading pathogens, and toxic protein aggregates. Additional functions of ULK1/2 have emerged beyond autophagy, including roles in protein trafficking, RNP granule dynamics, and signaling events impacting innate immunity, axon guidance, cellular homeostasis, and cell fate. Therefore, it is no surprise that alterations in ULK1/2 expression and activity have been linked with pathophysiological processes, including cancer, neurological disorders, and cardiovascular diseases. Growing evidence suggests that ULK1/2 function as biological rheostats, tuning cellular functions to intra and extra-cellular cues. Given their broad physiological relevance, ULK1/2 are candidate targets for small molecule activators or inhibitors that may pave the way for the development of therapeutics for the treatment of diseases in humans.
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Affiliation(s)
- Gautam Pareek
- Cell and Molecular Biology Department, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Mondira Kundu
- Cell and Molecular Biology Department, St. Jude Children's Research Hospital, Memphis, TN, USA.
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5
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Kraft C, Reggiori F. Phagophore closure, autophagosome maturation and autophagosome fusion during macroautophagy in the yeast Saccharomyces cerevisiae. FEBS Lett 2024; 598:73-83. [PMID: 37585559 DOI: 10.1002/1873-3468.14720] [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: 07/10/2023] [Revised: 08/07/2023] [Accepted: 08/07/2023] [Indexed: 08/18/2023]
Abstract
Macroautophagy, hereafter referred to as autophagy, is a complex process in which multiple membrane-remodeling events lead to the formation of a cisterna known as the phagophore, which then expands and closes into a double-membrane vesicle termed the autophagosome. During the past decade, enormous progress has been made in understanding the molecular function of the autophagy-related proteins and their role in generating these phagophores. In this Review, we discuss the current understanding of three membrane remodeling steps in autophagy that remain to be largely characterized; namely, the closure of phagophores, the maturation of the resulting autophagosomes into fusion-competent vesicles, and their fusion with vacuoles/lysosomes. Our review will mainly focus on the yeast Saccharomyces cerevisiae, which has been the leading model system for the study of molecular events in autophagy and has led to the discovery of the major mechanistic concepts, which have been found to be mostly conserved in higher eukaryotes.
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Affiliation(s)
- Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Germany
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Denmark
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6
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Guo P, Wang Y, Xu J, Yang Z, Zhang Z, Qian J, Hu J, Yin Z, Yang L, Liu M, Liu X, Li G, Zhang H, Rumsey R, Wang P, Zhang Z. Autophagy and cell wall integrity pathways coordinately regulate the development and pathogenicity through MoAtg4 phosphorylation in Magnaporthe oryzae. PLoS Pathog 2024; 20:e1011988. [PMID: 38289966 PMCID: PMC10857709 DOI: 10.1371/journal.ppat.1011988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 02/09/2024] [Accepted: 01/20/2024] [Indexed: 02/01/2024] Open
Abstract
Autophagy and Cell wall integrity (CWI) signaling are critical stress-responsive processes during fungal infection of host plants. In the rice blast fungus Magnaporthe oryzae, autophagy-related (ATG) proteins phosphorylate CWI kinases to regulate virulence; however, how autophagy interplays with CWI signaling to coordinate such regulation remains unknown. Here, we have identified the phosphorylation of ATG protein MoAtg4 as an important process in the coordination between autophagy and CWI in M. oryzae. The ATG kinase MoAtg1 phosphorylates MoAtg4 to inhibit the deconjugation and recycling of the key ATG protein MoAtg8. At the same time, MoMkk1, a core kinase of CWI, also phosphorylates MoAtg4 to attenuate the C-terminal cleavage of MoAtg8. Significantly, these two phosphorylation events maintain proper autophagy levels to coordinate the development and pathogenicity of the rice blast fungus.
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Affiliation(s)
- Pusheng Guo
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Yurong Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Jiayun Xu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Zhixiang Yang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Ziqi Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Jinyi Qian
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Jiexiong Hu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Ziyi Yin
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Leiyun Yang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Muxing Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Xinyu Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Gang Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Ryan Rumsey
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Ping Wang
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
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7
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Lee DH, Choi I, Park SJ, Kim S, Choi MS, Lee HS, Pai HS. Three consecutive cytosolic glycolysis enzymes modulate autophagic flux. PLANT PHYSIOLOGY 2023; 193:1797-1815. [PMID: 37539947 PMCID: PMC10602606 DOI: 10.1093/plphys/kiad439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 08/05/2023]
Abstract
Autophagy serves as an important recycling route for the growth and survival of eukaryotic organisms in nutrient-deficient conditions. Since starvation induces massive changes in the metabolic flux that are coordinated by key metabolic enzymes, specific processing steps of autophagy may be linked with metabolic flux-monitoring enzymes. We attempted to identify carbon metabolic genes that modulate autophagy using VIGS screening of 45 glycolysis- and Calvin-Benson cycle-related genes in Arabidopsis (Arabidopsis thaliana). Here, we report that three consecutive triose-phosphate-processing enzymes involved in cytosolic glycolysis, triose-phosphate-isomerase (TPI), glyceraldehyde-3-phosphate dehydrogenase (GAPC), and phosphoglycerate kinase (PGK), designated TGP, negatively regulate autophagy. Depletion of TGP enzymes causes spontaneous autophagy induction and increases AUTOPHAGY-RELATED 1 (ATG1) kinase activity. TGP enzymes interact with ATG101, a regulatory component of the ATG1 kinase complex. Spontaneous autophagy induction and abnormal growth under insufficient sugar in TGP mutants are suppressed by crossing with the atg101 mutant. Considering that triose-phosphates are photosynthates transported to the cytosol from active chloroplasts, the TGP enzymes would be strategically positioned to monitor the flow of photosynthetic sugars and modulate autophagy accordingly. Collectively, these results suggest that TGP enzymes negatively control autophagy acting upstream of the ATG1 complex, which is critical for seedling development.
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Affiliation(s)
- Du-Hwa Lee
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
- Department of Systems Biology, Yonsei University, Seoul 03722, Korea
| | - Ilyeong Choi
- Department of Systems Biology, Yonsei University, Seoul 03722, Korea
| | - Seung Jun Park
- Department of Systems Biology, Yonsei University, Seoul 03722, Korea
| | - Sumin Kim
- Department of Systems Biology, Yonsei University, Seoul 03722, Korea
| | - Min-Soo Choi
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Ho-Seok Lee
- Department of Biology, Kyung Hee University, Seoul 02447, Korea
- Center for Genome Engineering, Institute for Basic Science, Daejeon 34126, Korea
| | - Hyun-Sook Pai
- Department of Systems Biology, Yonsei University, Seoul 03722, Korea
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8
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Caraba B, Stirpe M, Palermo V, Vaccher U, Bianchi MM, Falcone C, Mazzoni C. Yeast Lsm Pro-Apoptotic Mutants Show Defects in Autophagy. Int J Mol Sci 2023; 24:13708. [PMID: 37762007 PMCID: PMC10530990 DOI: 10.3390/ijms241813708] [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: 07/18/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
LSM4 is an essential yeast gene encoding a component of different LSM complexes involved in the regulation of mRNA splicing, stability, and translation. In previous papers, we reported that the expression in S. cerevisiae of the K. lactis LSM4 gene lacking the C-terminal Q/N-rich domain in an Lsm4 null strain S. cerevisiae (Sclsm4Δ1) restored cell viability. Nevertheless, in this transformed strain, we observed some phenotypes that are typical markers of regulated cell death, reactive oxygen species (ROS), and oxidated RNA accumulation. In this paper, we report that a similar truncation operated in the S. cerevisiae LSM4 gene confers on cells the same phenotypes observed with the K. lactis lsm4Δ1 gene. Up until now, there was no evidence of the direct involvement of LSM4 in autophagy. Here we found that the Sclsm4Δ1 mutant showed a block in the autophagic process and was very sensitive to nitrogen starvation or treatment with low doses of rapamycin, an inducer of autophagy. Moreover, both during nitrogen starvation and aging, the Sclsm4Δ1 mutant accumulated cytoplasmic autophagy-related structures, suggesting a role of Lsm4 in a later step of the autophagy process.
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Affiliation(s)
| | | | | | | | | | | | - Cristina Mazzoni
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy; (B.C.); (M.S.); (V.P.); (U.V.); (M.M.B.); (C.F.)
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9
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Lee Y, Kim B, Jang HS, Huh WK. Atg1-dependent phosphorylation of Vps34 is required for dynamic regulation of the phagophore assembly site and autophagy in Saccharomyces cerevisiae. Autophagy 2023; 19:2428-2442. [PMID: 36803233 PMCID: PMC10392759 DOI: 10.1080/15548627.2023.2182478] [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: 07/28/2022] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
Macroautophagy/autophagy is a key catabolic pathway in which double-membrane autophagosomes sequester various substrates destined for degradation, enabling cells to maintain homeostasis and survive under stressful conditions. Several autophagy-related (Atg) proteins are recruited to the phagophore assembly site (PAS) and cooperatively function to generate autophagosomes. Vps34 is a class III phosphatidylinositol 3-kinase, and Atg14-containing Vps34 complex I plays essential roles in autophagosome formation. However, the regulatory mechanisms of yeast Vps34 complex I are still poorly understood. Here, we demonstrate that Atg1-dependent phosphorylation of Vps34 is required for robust autophagy activity in Saccharomyces cerevisiae. Following nitrogen starvation, Vps34 in complex I is selectively phosphorylated on multiple serine/threonine residues in its helical domain. This phosphorylation is important for full autophagy activation and cell survival. The absence of Atg1 or its kinase activity leads to complete loss of Vps34 phosphorylation in vivo, and Atg1 directly phosphorylates Vps34 in vitro, regardless of its complex association type. We also demonstrate that the localization of Vps34 complex I to the PAS provides a molecular basis for the complex I-specific phosphorylation of Vps34. This phosphorylation is required for the normal dynamics of Atg18 and Atg8 at the PAS. Together, our results reveal a novel regulatory mechanism of yeast Vps34 complex I and provide new insights into the Atg1-dependent dynamic regulation of the PAS.Abbreviations: ATG: autophagy-related; BARA: the repeated, autophagy-specific Co-IP: co-immunoprecipitation; GFP: green fluorescent protein; IP-MS: immunoprecipitation followed by tandem mass spectrometry; NTD: the N-terminal domain; PAS: phagophore assembly site; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: phosphatidylinositol 3-kinase; SUR: structurally uncharacterized region; Vps34[KD]: Vps34D731N.
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Affiliation(s)
- Yongook Lee
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Bongkeun Kim
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hae-Soo Jang
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
- Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
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10
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Arlt H, Raman B, Filali-Mouncef Y, Hu Y, Leytens A, Hardenberg R, Guimarães R, Kriegenburg F, Mari M, Smaczynska-de Rooij II, Ayscough KR, Dengjel J, Ungermann C, Reggiori F. The dynamin Vps1 mediates Atg9 transport to the sites of autophagosome formation. J Biol Chem 2023; 299:104712. [PMID: 37060997 DOI: 10.1016/j.jbc.2023.104712] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/14/2023] [Accepted: 04/06/2023] [Indexed: 04/17/2023] Open
Abstract
Autophagy is a key process in eukaryotes to maintain cellular homeostasis by delivering cellular components to lysosomes/vacuoles for degradation and reuse of the resulting metabolites. Membrane rearrangements and trafficking events are mediated by the core machinery of autophagy-related (Atg) proteins, which carry out a variety of functions. How Atg9, a lipid scramblase and the only conserved transmembrane protein within this core Atg machinery, is trafficked during autophagy remained largely unclear. Here, we addressed this question in yeast Saccharomyces cerevisiae and found that retromer complex and dynamin Vps1 mutants alter Atg9 subcellular distribution and severely impair the autophagic flux by affecting two separate autophagy steps. We provide evidence that Vps1 interacts with Atg9 at Atg9 reservoirs. In the absence of Vps1, Atg9 fails to reach the sites of autophagosome formation, and this results in an autophagy defect. The function of Vps1 in autophagy requires its GTPase activity. Moreover, Vps1 point mutants associated with human diseases such as microcytic anemia and Charcot-Marie-Tooth are unable to sustain autophagy and affect Atg9 trafficking. Together, our data provide novel insights on the role of dynamins in Atg9 trafficking and suggest that a defect in this autophagy step could contribute to severe human pathologies.
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Affiliation(s)
- Henning Arlt
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Babu Raman
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Yasmina Filali-Mouncef
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Yan Hu
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark
| | - Alexandre Leytens
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Ralph Hardenberg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rodrigo Guimarães
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Franziska Kriegenburg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark
| | | | - Kathryn R Ayscough
- Department of Biomedical Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Christian Ungermann
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark; Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark.
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11
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Mallén-Ponce MJ, Gámez-Arcas S, Pérez-Pérez ME. Redox partner interactions in the ATG8 lipidation system in microalgae. Free Radic Biol Med 2023; 203:58-68. [PMID: 37028463 DOI: 10.1016/j.freeradbiomed.2023.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/29/2023] [Accepted: 04/05/2023] [Indexed: 04/09/2023]
Abstract
Autophagy is a catabolic pathway that functions as a degradative and recycling process to maintain cellular homeostasis in most eukaryotic cells, including photosynthetic organisms such as microalgae. This process involves the formation of double-membrane vesicles called autophagosomes, which engulf the material to be degraded and recycled in lytic compartments. Autophagy is mediated by a set of highly conserved autophagy-related (ATG) proteins that play a fundamental role in the formation of the autophagosome. The ATG8 ubiquitin-like system catalyzes the conjugation of ATG8 to the lipid phosphatidylethanolamine, an essential reaction in the autophagy process. Several studies identified the ATG8 system and other core ATG proteins in photosynthetic eukaryotes. However, how ATG8 lipidation is driven and regulated in these organisms is not fully understood yet. A detailed analysis of representative genomes from the entire microalgal lineage revealed a high conservation of ATG proteins in these organisms with the remarkable exception of red algae, which likely lost ATG genes before diversification. Here, we examine in silico the mechanisms and dynamic interactions between different components of the ATG8 lipidation system in plants and algae. Moreover, we also discuss the role of redox post-translational modifications in the regulation of ATG proteins and the activation of autophagy in these organisms by reactive oxygen species.
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Affiliation(s)
- Manuel J Mallén-Ponce
- Institut de Biologie Paris-Seine, UMR 7238, CNRS, Sorbonne Université, 75005, Paris, France
| | - Samuel Gámez-Arcas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092, Sevilla, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092, Sevilla, Spain.
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12
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Sánchez-Martín P, Kriegenburg F, Alves L, Adam J, Elsaesser J, Babic R, Mancilla H, Licheva M, Tascher G, Münch C, Eimer S, Kraft C. ULK1-mediated phosphorylation regulates the conserved role of YKT6 in autophagy. J Cell Sci 2023; 136:jcs260546. [PMID: 36644903 PMCID: PMC10022743 DOI: 10.1242/jcs.260546] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/06/2023] [Indexed: 01/17/2023] Open
Abstract
Autophagy is a catabolic process during which cytosolic material is enwrapped in a newly formed double-membrane structure called the autophagosome, and subsequently targeted for degradation in the lytic compartment of the cell. The fusion of autophagosomes with the lytic compartment is a tightly regulated step and involves membrane-bound SNARE proteins. These play a crucial role as they promote lipid mixing and fusion of the opposing membranes. Among the SNARE proteins implicated in autophagy, the essential SNARE protein YKT6 is the only SNARE protein that is evolutionarily conserved from yeast to humans. Here, we show that alterations in YKT6 function, in both mammalian cells and nematodes, produce early and late autophagy defects that result in reduced survival. Moreover, mammalian autophagosomal YKT6 is phospho-regulated by the ULK1 kinase, preventing premature bundling with the lysosomal SNARE proteins and thereby inhibiting autophagosome-lysosome fusion. Together, our findings reveal that timely regulation of the YKT6 phosphorylation status is crucial throughout autophagy progression and cell survival.
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Affiliation(s)
- Pablo Sánchez-Martín
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Franziska Kriegenburg
- 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
| | - Ludovico Alves
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt, Germany
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Julius Adam
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Jana Elsaesser
- 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
| | - Riccardo Babic
- 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
| | - Hector Mancilla
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, 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
| | - Georg Tascher
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Christian Münch
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, 60590 Frankfurt, Germany
| | - Stefan Eimer
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - 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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13
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Yao W, Li Y, Chen Y, Chen Y, Xie Y, Ye M, Zhang Y, Chen X, Wu X, Feng Y, Hong Z, Wang Y, Liu W, Yi C. Atg1-mediated Atg11 phosphorylation is required for selective autophagy by regulating its association with receptor proteins. Autophagy 2023; 19:180-188. [PMID: 35427192 PMCID: PMC9809958 DOI: 10.1080/15548627.2022.2063494] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Atg11 is an adaptor protein required for the induction of selective autophagy via receptor binding. However, our understanding of the molecular mechanisms by which it regulates selective autophagy remains incomplete. Here, we show that Atg11 is phosphorylated by Atg1. Rapamycin treatment or starvation conditions induced slower electrophoretic mobility of Atg11 in an Atg1 kinase activity-dependent manner. Through in vitro kinase assays combined with mutagenesis, we determined that Atg1 phosphorylates S949, S1057, and S1064 residues in CC4 domain of Atg11. Replacing the three residues with alanine suppressed the cleavage of selective autophagy substrates for the cytoplasm-to-vacuole targeting (Cvt) pathway, mitophagy, reticulophagy, and pexophagy. The Atg11 mutant was defective in binding to related selective autophagy receptors. These results demonstrate a previously unknown function of Atg1 in regulation of selective autophagy via Atg11 phosphorylation.Abbreviations: AMPK: AMP-activated protein kinase; ATG: autophagy-related; Cvt: cytoplasm-to-vacuole targeting; FUNDC1: FUN14 domain-containing protein 1; GFP: green fluorescent protein; MTOR: mechanistic target of rapamycin kinase; PAS: phagophore assembly site; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PRKAC/PKA: protein kinase cAMP-activated; SD-G: glucose starvation; SD-N: nitrogen starvation; ULK1: unc-51 like autophagy activating kinase 1; λ-PPase: lambda protein phosphatase.
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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
| | - Yingcong Chen
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuting Chen
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Xie
- College of Chemistry and Bio-Engineering, Yichun University, Yichun, China
| | - Miaojuan Ye
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Ying Zhang
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Jiefang Road, Hangzhou, China,Institute of Translational Medicine, Zhejiang University School of Medicine, Kaixuan Road, Hangzhou, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Jiefang Road, Hangzhou, China,Institute of Translational Medicine, Zhejiang University School of Medicine, Kaixuan Road, 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
| | - Yuyao Feng
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi Hong
- ZJU-UoE Institute, Zhejiang University School of Medicine, Zhejiang University, Haining, China
| | - Yigang Wang
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, 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,CONTACT Cong Yi Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang310058, China
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14
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Chumpen Ramirez S, Gómez-Sánchez R, Verlhac P, Hardenberg R, Margheritis E, Cosentino K, Reggiori F, Ungermann C. --Atg9 interactions via its transmembrane domains are required for phagophore expansion during autophagy. Autophagy 2022:1-20. [PMID: 36354155 DOI: 10.1080/15548627.2022.2136340] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
During macroautophagy/autophagy, precursor cisterna known as phagophores expand and sequester portions of the cytoplasm and/or organelles, and subsequently close resulting in double-membrane transport vesicles called autophagosomes. Autophagosomes fuse with lysosomes/vacuoles to allow the degradation and recycling of their cargoes. We previously showed that sequential binding of yeast Atg2 and Atg18 to Atg9, the only conserved transmembrane protein in autophagy, at the extremities of the phagophore mediates the establishment of membrane contact sites between the phagophore and the endoplasmic reticulum. As the Atg2-Atg18 complex transfers lipids between adjacent membranes in vitro, it has been postulated that this activity and the scramblase activity of the trimers formed by Atg9 are required for the phagophore expansion. Here, we present evidence that Atg9 indeed promotes Atg2-Atg18 complex-mediated lipid transfer in vitro, although this is not the only requirement for its function in vivo. In particular, we show that Atg9 function is dramatically compromised by a F627A mutation within the conserved interface between the transmembrane domains of the Atg9 monomers. Although Atg9F627A self-interacts and binds to the Atg2-Atg18 complex, the F627A mutation blocks the phagophore expansion and thus autophagy progression. This phenotype is conserved because the corresponding human ATG9A mutant severely impairs autophagy as well. Importantly, Atg9F627A has identical scramblase activity in vitro like Atg9, and as with the wild-type protein enhances Atg2-Atg18-mediated lipid transfer. Collectively, our data reveal that interactions of Atg9 trimers via their transmembrane segments play a key role in phagophore expansion beyond Atg9's role as a lipid scramblase.Abbreviations: BafA1: bafilomycin A1; Cvt: cytoplasm-to-vacuole targeting; Cryo-EM: cryo-electron microscopy; ER: endoplasmic reticulum; GFP: green fluorescent protein; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MCS: membrane contact site; NBD-PE: N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine; PAS: phagophore assembly site; PE: phosphatidylethanolamine; prApe1: precursor Ape1; PtdIns3P: phosphatidylinositol-3-phosphate; SLB: supported lipid bilayer; SUV: small unilamellar vesicle; TMD: transmembrane domain; WT: wild type.
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Affiliation(s)
- Sabrina Chumpen Ramirez
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Rubén Gómez-Sánchez
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Pauline Verlhac
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ralph Hardenberg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | | | - Katia Cosentino
- Osnabrück University, Department of Biology/Chemistry, Osnabrück, Germany.,Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department of Biomedicine, Aarhus University, Ole Worms Alle 4, 8000 Aarhus C, Aarhus, Denmark.,Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus C, Denmark
| | - Christian Ungermann
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany.,Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
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15
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Cai YY, Li L, Zhu XM, Lu JP, Liu XH, Lin FC. The crucial role of the regulatory mechanism of the Atg1/ULK1 complex in fungi. Front Microbiol 2022; 13:1019543. [PMID: 36386635 PMCID: PMC9643702 DOI: 10.3389/fmicb.2022.1019543] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/10/2022] [Indexed: 12/05/2022] Open
Abstract
Autophagy, an evolutionarily conserved cellular degradation pathway in eukaryotes, is hierarchically regulated by autophagy-related genes (Atgs). The Atg1/ULK1 complex is the most upstream factor involved in autophagy initiation. Here,we summarize the recent studies on the structure and molecular mechanism of the Atg1/ULK1 complex in autophagy initiation, with a special focus on upstream regulation and downstream effectors of Atg1/ULK1. The roles of pathogenicity and autophagy aspects in Atg1/ULK1 complexes of various pathogenic hosts, including plants, insects, and humans, are also discussed in this work based on recent research findings. We establish a framework to study how the Atg1/ULK1 complex integrates the signals that induce autophagy in accordance with fungus to mammalian autophagy regulation pathways. This framework lays the foundation for studying the deeper molecular mechanisms of the Atg1 complex in pathogenic fungi.
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Affiliation(s)
- Ying-Ying Cai
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Lin Li
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Xue-Ming Zhu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jian-Ping Lu
- College of Life Science, Zhejiang University, Hangzhou, China
| | - Xiao-Hong Liu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Fu-Cheng Lin
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- *Correspondence: Fu-Cheng Lin,
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16
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Shedding Light on the Role of Phosphorylation in Plant Autophagy. FEBS Lett 2022; 596:2172-2185. [DOI: 10.1002/1873-3468.14352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/30/2022] [Accepted: 04/04/2022] [Indexed: 11/07/2022]
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17
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Post-Translational Modifications of ATG4B in the Regulation of Autophagy. Cells 2022; 11:cells11081330. [PMID: 35456009 PMCID: PMC9025542 DOI: 10.3390/cells11081330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 11/16/2022] Open
Abstract
Autophagy plays a key role in eliminating and recycling cellular components in response to stress, including starvation. Dysregulation of autophagy is observed in various diseases, including neurodegenerative diseases, cancer, and diabetes. Autophagy is tightly regulated by autophagy-related (ATG) proteins. Autophagy-related 4 (ATG4) is the sole cysteine protease, and four homologs (ATG4A–D) have been identified in mammals. These proteins have two domains: catalytic and short fingers. ATG4 facilitates autophagy by promoting autophagosome maturation through reversible lipidation and delipidation of seven autophagy-related 8 (ATG8) homologs, including microtubule-associated protein 1-light chain 3 (LC3) and GABA type A receptor-associated protein (GABARAP). Each ATG4 homolog shows a preference for a specific ATG8 homolog. Post-translational modifications of ATG4, including phosphorylation/dephosphorylation, O-GlcNAcylation, oxidation, S-nitrosylation, ubiquitination, and proteolytic cleavage, regulate its activity and ATG8 processing, thus modulating its autophagic activity. We reviewed recent advances in our understanding of the effect of post-translational modification on the regulation, activity, and function of ATG4, the main protease that controls autophagy.
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18
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Duarte PV, Hardenberg R, Mari M, Walter S, Reggiori F, Fröhlich F, Montoro AG, Ungermann C. The yeast LYST homolog Bph1 is a Rab5 effector and prevents Atg8 lipidation at endosomes. J Cell Sci 2022; 135:274866. [PMID: 35343566 DOI: 10.1242/jcs.259421] [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: 09/30/2021] [Accepted: 03/18/2022] [Indexed: 01/18/2023] Open
Abstract
Lysosomes mediate degradation of macromolecules to their precursors for their cellular recycling. Additionally, lysosome-related organelles mediate cell type-specific functions. The Chédiak-Higashi syndrome is an autosomal, recessive disease, in which loss of the protein LYST causes defects in lysosomes and lysosome-related organelles. The molecular function of LYST, however, is largely unknown. Here, we dissected the function of the yeast LYST homolog, Bph1. We show that Bph1 is an endosomal protein, and an effector of the minor Rab5 isoform Ypt52. Strikingly, the bph1▵ mutant has lipidated Atg8 on their endosomes, which is sorted via late endosomes into the vacuole lumen under non-autophagy inducing conditions. In agreement, proteomics of bph1▵ vacuoles reveal an accumulation of Atg8, reduced flux via selective autophagy, and defective endocytosis. Additionally, bph1▵ cells have reduced autophagic flux under starvation conditions. Our observations suggest that Bph1 is a novel Rab5 effector that maintains endosomal functioning. When lost, Atg8 is lipidated at endosomes even during normal growth and ends up in the vacuole lumen. Thus, our results contribute to the understanding of the role of LYST-related proteins and associated diseases.
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Affiliation(s)
- Prado Vargas Duarte
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Ralph Hardenberg
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Stefan Walter
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Florian Fröhlich
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany.,Osnabrück University, Department of Biology/Chemistry, Molecular Membrane Biology section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Ayelén González Montoro
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany.,Osnabrück University, Department of Biology/Chemistry, Cellular Communication Laboratory, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany.,Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
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19
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Fission Yeast Autophagy Machinery. Cells 2022; 11:cells11071086. [PMID: 35406650 PMCID: PMC8997447 DOI: 10.3390/cells11071086] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/19/2022] [Accepted: 03/22/2022] [Indexed: 01/27/2023] Open
Abstract
Autophagy is a conserved process that delivers cytoplasmic components to the vacuole/lysosome. It plays important roles in maintaining cellular homeostasis and conferring stress resistance. In the fission yeast Schizosaccharomyces pombe, autophagy is important for cell survival under nutrient depletion and ER stress conditions. Experimental analyses of fission yeast autophagy machinery in the last 10 years have unveiled both similarities and differences in autophagosome biogenesis mechanisms between fission yeast and other model eukaryotes for autophagy research, in particular, the budding yeast Saccharomyces cerevisiae. More recently, selective autophagy pathways that deliver hydrolytic enzymes, the ER, and mitochondria to the vacuole have been discovered in fission yeast, yielding novel insights into how cargo selectivity can be achieved in autophagy. Here, we review the progress made in understanding the autophagy machinery in fission yeast.
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20
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Molecular regulation of autophagosome formation. Biochem Soc Trans 2022; 50:55-69. [PMID: 35076688 PMCID: PMC9022990 DOI: 10.1042/bst20210819] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/21/2021] [Accepted: 01/04/2022] [Indexed: 12/11/2022]
Abstract
Macroautophagy, hereafter autophagy, is a degradative process conserved among eukaryotes, which is essential to maintain cellular homeostasis. Defects in autophagy lead to numerous human diseases, including various types of cancer and neurodegenerative disorders. The hallmark of autophagy is the de novo formation of autophagosomes, which are double-membrane vesicles that sequester and deliver cytoplasmic materials to lysosomes/vacuoles for degradation. The mechanism of autophagosome biogenesis entered a molecular era with the identification of autophagy-related (ATG) proteins. Although there are many unanswered questions and aspects that have raised some controversies, enormous advances have been done in our understanding of the process of autophagy in recent years. In this review, we describe the current knowledge about the molecular regulation of autophagosome formation, with a particular focus on budding yeast and mammalian cells.
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21
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The Landscape of Autophagy-Related (ATG) Genes and Functional Characterization of TaVAMP727 to Autophagy in Wheat. Int J Mol Sci 2022; 23:ijms23020891. [PMID: 35055085 PMCID: PMC8776105 DOI: 10.3390/ijms23020891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Autophagy is an indispensable biological process and plays crucial roles in plant growth and plant responses to both biotic and abiotic stresses. This study systematically identified autophagy-related proteins (ATGs) in wheat and its diploid and tetraploid progenitors and investigated their genomic organization, structure characteristics, expression patterns, genetic variation, and regulation network. We identified a total of 77, 51, 29, and 30 ATGs in wheat, wild emmer, T. urartu and A. tauschii, respectively, and grouped them into 19 subfamilies. We found that these autophagy-related genes (ATGs) suffered various degrees of selection during the wheat’s domestication and breeding processes. The genetic variations in the promoter region of Ta2A_ATG8a were associated with differences in seed size, which might be artificially selected for during the domestication process of tetraploid wheat. Overexpression of TaVAMP727 improved the cold, drought, and salt stresses resistance of the transgenic Arabidopsis and wheat. It also promoted wheat heading by regulating the expression of most ATGs. Our findings demonstrate how ATGs regulate wheat plant development and improve abiotic stress resistance. The results presented here provide the basis for wheat breeding programs for selecting varieties of higher yield which are capable of growing in colder, drier, and saltier areas.
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22
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Shatz O, Fraiberg M, Elazar Z. Atg1 kinase activity links PAS dissolution to balanced Atg8 conjugation. Trends Cell Biol 2021; 32:179-181. [PMID: 34969581 DOI: 10.1016/j.tcb.2021.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 11/15/2022]
Abstract
Atg1 phosphoregulates different steps and factors in autophagy. Schreiber et al. report in Molecular Cell on the cell-free identification of a negative feedback ejection of Atg1 from the pre-autophagosomal structure (PAS), followed by positive feedback recruitment of Atg1 to phagophore-resident Atg8-PE, followed by yet another, negative feedback inhibition of the Atg8 conjugation machinery.
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Affiliation(s)
- Oren Shatz
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Milana Fraiberg
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Zvulun Elazar
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
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23
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Schreiber A, Collins BC, Davis C, Enchev RI, Sedra A, D'Antuono R, Aebersold R, Peter M. Multilayered regulation of autophagy by the Atg1 kinase orchestrates spatial and temporal control of autophagosome formation. Mol Cell 2021; 81:5066-5081.e10. [PMID: 34798055 PMCID: PMC8693860 DOI: 10.1016/j.molcel.2021.10.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/23/2021] [Accepted: 10/26/2021] [Indexed: 12/26/2022]
Abstract
Autophagy is a conserved intracellular degradation pathway exerting various cytoprotective and homeostatic functions by using de novo double-membrane vesicle (autophagosome) formation to target a wide range of cytoplasmic material for vacuolar/lysosomal degradation. The Atg1 kinase is one of its key regulators, coordinating a complex signaling program to orchestrate autophagosome formation. Combining in vitro reconstitution and cell-based approaches, we demonstrate that Atg1 is activated by lipidated Atg8 (Atg8-PE), stimulating substrate phosphorylation along the growing autophagosomal membrane. Atg1-dependent phosphorylation of Atg13 triggers Atg1 complex dissociation, enabling rapid turnover of Atg1 complex subunits at the pre-autophagosomal structure (PAS). Moreover, Atg1 recruitment by Atg8-PE self-regulates Atg8-PE levels in the growing autophagosomal membrane by phosphorylating and thus inhibiting the Atg8-specific E2 and E3. Our work uncovers the molecular basis for positive and negative feedback imposed by Atg1 and how opposing phosphorylation and dephosphorylation events underlie the spatiotemporal regulation of autophagy.
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Affiliation(s)
- Anne Schreiber
- Cellular Degradation Systems Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK; Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland.
| | - Ben C Collins
- Institute of Molecular Systems Biology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; School of Biological Sciences, Queen's University of Belfast, 19 Chlorine Gardens, BT9 5DL Belfast, UK
| | - Colin Davis
- Cellular Degradation Systems Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK
| | - Radoslav I Enchev
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland; Visual Biochemistry Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK
| | - Angie Sedra
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Rocco D'Antuono
- Crick Advanced Light Microscopy (CALM) STP, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Matthias Peter
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland.
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24
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Non-canonical roles of autophagy proteins in endocytosis and exocytosis. Biochem Soc Trans 2021; 49:2841-2851. [PMID: 34783341 DOI: 10.1042/bst20210811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/21/2021] [Accepted: 10/25/2021] [Indexed: 01/18/2023]
Abstract
Autophagy, the pathways that degrade cytoplasmic constituents in lysosomes, contribute to most biological processes from aging and neurodegeneration to pathogen restriction and immunity. In recent years, it was realized that the autophagy machinery serves additional functions, primarily in endo- and exocytosis. In this review, I summarize recent advances in our understanding on how these non-canonical functions differ from canonical macroautophagy, and contribute to immune activation and viral replication. Understanding these pathways will allow us to harness them for the treatment of human diseases, as well as appreciate how cells use modules of membrane remodeling and trafficking for multiple biological functions.
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25
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Li B, Song S, Wei X, Tang G, Wang C. Activation of microlipophagy during early infection of insect hosts by Metarhizium robertsii. Autophagy 2021; 18:608-623. [PMID: 34130590 DOI: 10.1080/15548627.2021.1943179] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The requirement of macroautophagic/autophagic machinery for filamentous fungal development and pathogenicity has been recognized, but the underlying effects and mechanisms remain elusive. The insect pathogenic fungus Metarhizium robertsii infects hosts by cuticular penetration through the formation of the infection structure appressoria. Here, we show that autophagic fluxes were highly activated during the appressorial formation of M. robertsii. Genome-wide deletion of the autophagy-related genes and insect bioassays identified 10 of 23 encoded MrATG genes with requirements for topical fungal infection of insect hosts. Besides the defect in forming appressoria on insects (two null mutants), these virulence-reduced mutants were largely impaired in penetrating cellophane membrane and insect cuticles, suggesting their failures in generating proper appressorium turgor. We found that the conidial storage of lipid droplets (LDs) had no obvious difference between strains, but autophagic LD degradation was impaired in different mutants. After induction of cell autophagy by nitrogen starvation, we found that LD entry into vacuoles was unaffected in the selected mutant cells with potential failures in forming autophagosomes. The finding therefore reveals a microlipophagy machinery employed in this fungus and that the direct engulfment of LDs occurs without inhibition by the downstream defective lipolysis. Our data first unveil the activation and contribution of microlipophagy to fungal infection biology. The obtained technique may benefit future detection of microlipophagy in different organisms by examining vacuolar or lysosomal engulfment of LDs in core autophagic gene deletion mutants.
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Affiliation(s)
- Bing Li
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuangxiu Song
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuefei Wei
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guirong Tang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chengshu Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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26
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Münz C. Non-canonical functions of autophagy proteins in immunity and infection. Mol Aspects Med 2021; 82:100987. [PMID: 34147281 DOI: 10.1016/j.mam.2021.100987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/20/2021] [Accepted: 06/08/2021] [Indexed: 10/21/2022]
Abstract
The molecular machinery of macroautophagy, a catabolic pathway for cytoplasmic constituent degradation in lysosomes, remodels membranes by lipid phosphorylation and conjugation of LC3 and GABARAP proteins. In recent year it has become clear that these membrane modifications also regulate endo- and exocytosis. Here I will discuss recent evidence of how such non-canonical functions of the macroautophagy machinery with its autophagy related gene (atg) products influences infectious viral particle secretion, inflammation, and MHC restricted antigen presentation. Especially LC3-Associated Phagocytosis and ATG supported exocytosis will be high-lighted during immunity and infection.
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Affiliation(s)
- Christian Münz
- Viral Immunobiology, Institute of Experimental Immunology, University of Zurich, Switzerland.
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27
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Barz S, Kriegenburg F, Sánchez-Martín P, Kraft C. Small but mighty: Atg8s and Rabs in membrane dynamics during autophagy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119064. [PMID: 34048862 PMCID: PMC8261831 DOI: 10.1016/j.bbamcr.2021.119064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/04/2021] [Accepted: 05/21/2021] [Indexed: 11/17/2022]
Abstract
Autophagy is a degradative pathway during which autophagosomes are formed that enwrap cytosolic material destined for turnover within the lytic compartment. Autophagosome biogenesis requires controlled lipid and membrane rearrangements to allow the formation of an autophagosomal seed and its subsequent elongation into a fully closed and fusion-competent double membrane vesicle. Different membrane remodeling events are required, which are orchestrated by the distinct autophagy machinery. An important player among these autophagy proteins is the small lipid-modifier Atg8. Atg8 proteins facilitate various aspects of autophagosome formation and serve as a binding platform for autophagy factors. Also Rab GTPases have been implicated in autophagosome biogenesis. As Atg8 proteins interact with several Rab GTPase regulators, they provide a possible link between autophagy progression and Rab GTPase activity. Here, we review central aspects in membrane dynamics during autophagosome biogenesis with a focus on Atg8 proteins and selected Rab GTPases.
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Affiliation(s)
- Saskia Barz
- 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
| | - Franziska Kriegenburg
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Pablo Sánchez-Martín
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - 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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28
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Licheva M, Raman B, Kraft C, Reggiori F. Phosphoregulation of the autophagy machinery by kinases and phosphatases. Autophagy 2021; 18:104-123. [PMID: 33970777 PMCID: PMC8865292 DOI: 10.1080/15548627.2021.1909407] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cells use post-translational modifications to diversify and dynamically coordinate the function and properties of protein networks within various cellular processes. For example, the process of autophagy strongly depends on the balanced action of kinases and phosphatases. Highly conserved from the budding yeast Saccharomyces cerevisiae to humans, autophagy is a tightly regulated self-degradation process that is crucial for survival, stress adaptation, maintenance of cellular and organismal homeostasis, and cell differentiation and development. Many studies have emphasized the importance of kinases and phosphatases in the regulation of autophagy and identified many of the core autophagy proteins as their direct targets. In this review, we summarize the current knowledge on kinases and phosphatases acting on the core autophagy machinery and discuss the relevance of phosphoregulation for the overall process of autophagy.
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Affiliation(s)
- Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Babu Raman
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
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29
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Nguyen TN, Padman BS, Zellner S, Khuu G, Uoselis L, Lam WK, Skulsuppaisarn M, Lindblom RSJ, Watts EM, Behrends C, Lazarou M. ATG4 family proteins drive phagophore growth independently of the LC3/GABARAP lipidation system. Mol Cell 2021; 81:2013-2030.e9. [PMID: 33773106 DOI: 10.1016/j.molcel.2021.03.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 10/20/2020] [Accepted: 02/25/2021] [Indexed: 02/08/2023]
Abstract
The sequestration of damaged mitochondria within double-membrane structures termed autophagosomes is a key step of PINK1/Parkin mitophagy. The ATG4 family of proteases are thought to regulate autophagosome formation exclusively by processing the ubiquitin-like ATG8 family (LC3/GABARAPs). We discover that human ATG4s promote autophagosome formation independently of their protease activity and of ATG8 family processing. ATG4 proximity networks reveal a role for ATG4s and their proximity partners, including the immune-disease protein LRBA, in ATG9A vesicle trafficking to mitochondria. Artificial intelligence-directed 3D electron microscopy of phagophores shows that ATG4s promote phagophore-ER contacts during the lipid-transfer phase of autophagosome formation. We also show that ATG8 removal during autophagosome maturation does not depend on ATG4 activity. Instead, ATG4s can disassemble ATG8-protein conjugates, revealing a role for ATG4s as deubiquitinating-like enzymes. These findings establish non-canonical roles of the ATG4 family beyond the ATG8 lipidation axis and provide an AI-driven framework for rapid 3D electron microscopy.
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Affiliation(s)
- Thanh Ngoc Nguyen
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia.
| | - Benjamin Scott Padman
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Susanne Zellner
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
| | - Grace Khuu
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Louise Uoselis
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Wai Kit Lam
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Marvin Skulsuppaisarn
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Runa S J Lindblom
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Emily M Watts
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Christian Behrends
- Munich Cluster for Systems Neurology, Medical Faculty, Ludwig-Maximilians-University München, Munich, Germany
| | - Michael Lazarou
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia.
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30
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Pérez-Pérez ME, Lemaire SD, Crespo JL. The ATG4 protease integrates redox and stress signals to regulate autophagy. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3340-3351. [PMID: 33587749 DOI: 10.1093/jxb/erab063] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Autophagy is a highly conserved degradative pathway that ensures cellular homeostasis through the removal of damaged or useless intracellular components including proteins, membranes, or even entire organelles. A main hallmark of autophagy is the biogenesis of autophagosomes, double-membrane vesicles that engulf and transport to the vacuole the material to be degraded and recycled. The formation of autophagosomes responds to integrated signals produced as a consequence of metabolic reactions or different types of stress and is mediated by the coordinated action of core autophagy-related (ATG) proteins. ATG4 is a key Cys-protease with a dual function in both ATG8 lipidation and free ATG8 recycling whose balance is crucial for proper biogenesis of the autophagosome. ATG4 is conserved in the green lineage, and its regulation by different post-translational modifications has been reported in the model systems Chlamydomonas reinhardtii and Arabidopsis. In this review, we discuss the major role of ATG4 in the integration of stress and redox signals that regulate autophagy in algae and plants.
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Affiliation(s)
- María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Avda. Américo Vespucio, Sevilla, Spain
| | - Stéphane D Lemaire
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, Paris, France
- CNRS, Sorbonne Université, Institut de Biologie Physico-Chimique, Paris, France
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Sevilla, Avda. Américo Vespucio, Sevilla, Spain
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31
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Melia TJ, Lystad AH, Simonsen A. Autophagosome biogenesis: From membrane growth to closure. J Cell Biol 2021; 219:151729. [PMID: 32357219 PMCID: PMC7265318 DOI: 10.1083/jcb.202002085] [Citation(s) in RCA: 158] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/04/2020] [Accepted: 04/06/2020] [Indexed: 12/14/2022] Open
Abstract
Autophagosome biogenesis involves de novo formation of a membrane that elongates to sequester cytoplasmic cargo and closes to form a double-membrane vesicle (an autophagosome). This process has remained enigmatic since its initial discovery >50 yr ago, but our understanding of the mechanisms involved in autophagosome biogenesis has increased substantially during the last 20 yr. Several key questions do remain open, however, including, What determines the site of autophagosome nucleation? What is the origin and lipid composition of the autophagosome membrane? How is cargo sequestration regulated under nonselective and selective types of autophagy? This review provides key insight into the core molecular mechanisms underlying autophagosome biogenesis, with a specific emphasis on membrane modeling events, and highlights recent conceptual advances in the field.
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Affiliation(s)
- Thomas J Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Alf H Lystad
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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32
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Ligeon LA, Pena-Francesch M, Vanoaica LD, Núñez NG, Talwar D, Dick TP, Münz C. Oxidation inhibits autophagy protein deconjugation from phagosomes to sustain MHC class II restricted antigen presentation. Nat Commun 2021; 12:1508. [PMID: 33686057 PMCID: PMC7940406 DOI: 10.1038/s41467-021-21829-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 02/15/2021] [Indexed: 01/31/2023] Open
Abstract
LC3-associated phagocytosis (LAP) contributes to a wide range of cellular processes and notably to immunity. The stabilization of phagosomes by the macroautophagy machinery in human macrophages can maintain antigen presentation on MHC class II molecules. However, the molecular mechanisms involved in the formation and maturation of the resulting LAPosomes are not completely understood. Here, we show that reactive oxygen species (ROS) produced by NADPH oxidase 2 (NOX2) stabilize LAPosomes by inhibiting LC3 deconjugation from the LAPosome cytosolic surface. NOX2 residing in the LAPosome membrane generates ROS to cause oxidative inactivation of the protease ATG4B, which otherwise releases LC3B from LAPosomes. An oxidation-insensitive ATG4B mutant compromises LAP and thereby impedes sustained MHC class II presentation of exogenous Candida albicans antigens. Redox regulation of ATG4B is thereby an important mechanism for maintaining LC3 decoration of LAPosomes to support antigen processing for MHC class II presentation.
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Affiliation(s)
- Laure-Anne Ligeon
- grid.7400.30000 0004 1937 0650Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Maria Pena-Francesch
- grid.7400.30000 0004 1937 0650Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Liliana Danusia Vanoaica
- grid.7400.30000 0004 1937 0650Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Nicolás Gonzalo Núñez
- grid.7400.30000 0004 1937 0650Inflammation Research, Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
| | - Deepti Talwar
- grid.7497.d0000 0004 0492 0584Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Heidelberg, Germany ,grid.7700.00000 0001 2190 4373Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Tobias P. Dick
- grid.7497.d0000 0004 0492 0584Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Heidelberg, Germany ,grid.7700.00000 0001 2190 4373Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Christian Münz
- grid.7400.30000 0004 1937 0650Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland
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33
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Li X, Sun L, Yan G, Yan X. PFKP facilitates ATG4B phosphorylation during amino acid deprivation-induced autophagy. Cell Signal 2021; 82:109956. [PMID: 33607258 DOI: 10.1016/j.cellsig.2021.109956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/29/2021] [Accepted: 02/13/2021] [Indexed: 12/09/2022]
Abstract
ATG4B facilitates autophagy by promoting autophagosome maturation through the reversible lipidation and delipidation of LC3. Recent reports have shown that phosphorylation of ATG4B regulates its activity and LC3 processing, leading to modulate autophagy activity. However, the mechanism about how ATG4B phosphorylation is involved in amino acid deprivation-induced autophagy is unclear. Here, we combined the tandem affinity purification with mass spectrometry (MS) and identified the ATG4B-interacting proteins including its well-known partner gamma-aminobutyric acid receptor-associated protein (GABARAP, a homolog of LC3) and phosphofructokinase 1 platelet isoform (PFKP). Further immunoprecipitation assays showed that amino acid deprivation strengthened the interaction between ATG4B and PFKP. By genetic depletion of PFKP using CRISPR/Cas9, we uncovered that PFKP loss reduced the degradation of LC3-II and p62 due to a partial block in autophagic flux. Furthermore, MS analysis of Flag-tagged ATG4B immunoprecipitates identified phosphorylation of ATG4B serine 34 residue (S34) and PFKP serine 386 residue (S386) under amino acid deprivation condition. In vitro kinase assay validated that PFKP functioning as a protein kinase phosphorylated ATG4B at S34. This phosphorylation could enhance ATG4B activity and p62 degradation. In addition, PFKP S386 phosphorylation was important to ATG4B S34 phosphorylation and autophagy in HEK293T cells. In brief, our findings describe that PFKP, a rate-limiting enzyme in the glycolytic pathway, functions as a protein kinase for ATG4B to regulate ATG4B activity and autophagy under amino acid deprivation condition.
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Affiliation(s)
- Xiuzhi Li
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Lingling Sun
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Guokai Yan
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China
| | - Xianghua Yan
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei 430070, China.
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34
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Xia F, Liu P, Li M. The regulatory factors and pathological roles of autophagy-related protein 4 in diverse diseases: Recent research advances. Med Res Rev 2020; 41:1644-1675. [PMID: 33314291 DOI: 10.1002/med.21772] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 12/12/2022]
Abstract
Macroautophagy (autophagy) is an evolutionarily conserved and dynamic degradation/recycling pathway in which portions of the cytoplasm, such as dysfunctional proteins and surplus organelles, are engulfed by double-membrane bound vesicles through a lysosome-dependent process. As the only proteolytic enzyme of the core mammalian autophagy proteins, autophagy-related protein 4 (ATG4) primes newly synthesized pro-light chain 3 (LC3) to form LC3-I that attaches to phosphatidylethanolamine and delipidates LC3-PE to LC3-I for recycling. Besides autophagy, ATG4 has been shown to be involved in regulating various biological and pathological processes. The roles of ATG4 in cancer therapy, a methodology for ATG4 activity detection, and the discovery of chemical modulators have been well-reviewed. However, a comprehensive summary on how ATG4 is regulated by multiple factors and, thereby, how ATG4 influences autophagy or other pathways remains lacking. In this paper, we summarize multiple processes and molecules that regulate the activity of ATG4, such as micro-RNAs, posttranslational modifications, and small molecules. Additionally, we focus on the relationship between ATG4 and diverse diseases, including cancer, neurodegeneration, microbial infection, and other diseases. It provides insight regarding potential ATG4-targeted therapeutic opportunities, which could be beneficial for future studies and human health.
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Affiliation(s)
- Fan Xia
- Department of Pharmacology and Toxicology, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, National and Local United Engineering Lab of Druggability and New Drugs Evaluation, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Peiqing Liu
- Department of Pharmacology and Toxicology, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, National and Local United Engineering Lab of Druggability and New Drugs Evaluation, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Min Li
- Department of Pharmacology and Toxicology, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, National and Local United Engineering Lab of Druggability and New Drugs Evaluation, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
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35
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Barz S, Kriegenburg F, Henning A, Bhattacharya A, Mancilla H, Sánchez-Martín P, Kraft C. Atg1 kinase regulates autophagosome-vacuole fusion by controlling SNARE bundling. EMBO Rep 2020; 21:e51869. [PMID: 33274589 PMCID: PMC7726815 DOI: 10.15252/embr.202051869] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/26/2022] Open
Abstract
Autophagy mediates the degradation of cytoplasmic material. Upon autophagy induction, autophagosomes form a sealed membrane around the cargo and fuse with the lytic compartment to release the cargo for degradation. In order to avoid premature fusion of immature autophagosomal membranes with the lytic compartment, this process needs to be tightly regulated. Several factors mediating autophagosome–vacuole fusion have recently been identified. In budding yeast, autophagosome–vacuole fusion requires the R‐SNARE Ykt6 on the autophagosome, together with the three Q‐SNAREs Vam3, Vam7, and Vti1 on the vacuole. However, how these SNAREs are regulated during the fusion process is poorly understood. In this study, we investigate the regulation of Ykt6. We found that Ykt6 is directly phosphorylated by Atg1 kinase, which keeps this SNARE in an inactive state. Ykt6 phosphorylation prevents SNARE bundling by disrupting its interaction with the vacuolar SNAREs Vam3 and Vti1, thereby preventing premature autophagosome–vacuole fusion. These findings shed new light on the regulation of autophagosome–vacuole fusion and reveal a further step in autophagy controlled by the Atg1 kinase.
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Affiliation(s)
- Saskia Barz
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Franziska Kriegenburg
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anna Henning
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anuradha Bhattacharya
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Hector Mancilla
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Pablo Sánchez-Martín
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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36
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Hu Z, Raucci S, Jaquenoud M, Hatakeyama R, Stumpe M, Rohr R, Reggiori F, De Virgilio C, Dengjel J. Multilayered Control of Protein Turnover by TORC1 and Atg1. Cell Rep 2020; 28:3486-3496.e6. [PMID: 31553916 DOI: 10.1016/j.celrep.2019.08.069] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/19/2019] [Accepted: 08/22/2019] [Indexed: 12/13/2022] Open
Abstract
The target of rapamycin complex 1 (TORC1) is a master regulator of cell homeostasis, which promotes anabolic reactions and synchronously inhibits catabolic processes such as autophagy-mediated protein degradation. Its prime autophagy target is Atg13, a subunit of the Atg1 kinase complex that acts as the gatekeeper of canonical autophagy. To study whether the activities of TORC1 and Atg1 are coupled through additional, more intricate control mechanisms than simply this linear pathway, we analyzed the epistatic relationship between TORC1 and Atg1 by using quantitative phosphoproteomics. Our in vivo data, combined with targeted in vitro TORC1 and Atg1 kinase assays, not only uncover numerous TORC1 and Atg1 effectors, but also suggest distinct bi-directional regulatory feedback loops and characterize Atg29 as a commonly regulated downstream target of both TORC1 and Atg1. Thus, an exquisitely multilayered regulatory network appears to coordinate TORC1 and Atg1 activities to robustly tune autophagy in response to nutritional cues.
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Affiliation(s)
- Zehan Hu
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Serena Raucci
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Malika Jaquenoud
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Riko Hatakeyama
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Michael Stumpe
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Rudolf Rohr
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells & Systems, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, the Netherlands
| | | | - Jörn Dengjel
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland.
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37
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Gao J, Kurre R, Rose J, Walter S, Fröhlich F, Piehler J, Reggiori F, Ungermann C. Function of the SNARE Ykt6 on autophagosomes requires the Dsl1 complex and the Atg1 kinase complex. EMBO Rep 2020; 21:e50733. [PMID: 33025734 PMCID: PMC7726795 DOI: 10.15252/embr.202050733] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 12/11/2022] Open
Abstract
The mechanism and regulation of fusion between autophagosomes and lysosomes/vacuoles are still only partially understood in both yeast and mammals. In yeast, this fusion step requires SNARE proteins, the homotypic vacuole fusion and protein sorting (HOPS) tethering complex, the RAB7 GTPase Ypt7, and its guanine nucleotide exchange factor (GEF) Mon1‐Ccz1. We and others recently identified Ykt6 as the autophagosomal SNARE protein. However, it has not been resolved when and how lipid‐anchored Ykt6 is recruited onto autophagosomes. Here, we show that Ykt6 is recruited at an early stage of the formation of these carriers through a mechanism that depends on endoplasmic reticulum (ER)‐resident Dsl1 complex and COPII‐coated vesicles. Importantly, Ykt6 activity on autophagosomes is regulated by the Atg1 kinase complex, which inhibits Ykt6 through direct phosphorylation. Thus, our findings indicate that the Ykt6 pool on autophagosomal membranes is kept inactive by Atg1 phosphorylation, and once an autophagosome is ready to fuse with vacuole, Ykt6 dephosphorylation allows its engagement in the fusion event.
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Affiliation(s)
- Jieqiong Gao
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Rainer Kurre
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany
| | - Jaqueline Rose
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Molecular Membrane Biology Group, University of Osnabrück, Osnabrück, Germany
| | - Jacob Piehler
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Osnabrück, Germany.,Department of Biology/Chemistry, Biophysics Section, University of Osnabrück, Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
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38
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Sawa-Makarska J, Baumann V, Coudevylle N, von Bülow S, Nogellova V, Abert C, Schuschnig M, Graef M, Hummer G, Martens S. Reconstitution of autophagosome nucleation defines Atg9 vesicles as seeds for membrane formation. Science 2020; 369:eaaz7714. [PMID: 32883836 PMCID: PMC7610778 DOI: 10.1126/science.aaz7714] [Citation(s) in RCA: 146] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 05/16/2020] [Accepted: 07/06/2020] [Indexed: 12/15/2022]
Abstract
Autophagosomes form de novo in a manner that is incompletely understood. Particularly enigmatic are autophagy-related protein 9 (Atg9)-containing vesicles that are required for autophagy machinery assembly but do not supply the bulk of the autophagosomal membrane. In this study, we reconstituted autophagosome nucleation using recombinant components from yeast. We found that Atg9 proteoliposomes first recruited the phosphatidylinositol 3-phosphate kinase complex, followed by Atg21, the Atg2-Atg18 lipid transfer complex, and the E3-like Atg12-Atg5-Atg16 complex, which promoted Atg8 lipidation. Furthermore, we found that Atg2 could transfer lipids for Atg8 lipidation. In selective autophagy, these reactions could potentially be coupled to the cargo via the Atg19-Atg11-Atg9 interactions. We thus propose that Atg9 vesicles form seeds that establish membrane contact sites to initiate lipid transfer from compartments such as the endoplasmic reticulum.
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Affiliation(s)
- Justyna Sawa-Makarska
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria.
| | - Verena Baumann
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Nicolas Coudevylle
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Sören von Bülow
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Veronika Nogellova
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Christine Abert
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Martina Schuschnig
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria
| | - Martin Graef
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
- Institute for Biophysics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Sascha Martens
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria.
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39
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Gatica D, Damasio A, Pascual C, Klionsky DJ, Ragusa MJ, Popelka H. The carboxy terminus of yeast Atg13 binds phospholipid membrane via motifs that overlap with the Vac8-interacting domain. Autophagy 2020; 16:1007-1020. [PMID: 31352862 PMCID: PMC7469566 DOI: 10.1080/15548627.2019.1648117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 07/15/2019] [Accepted: 07/22/2019] [Indexed: 10/26/2022] Open
Abstract
Macroautophagy/autophagy is a conserved catabolic recycling pathway involving the sequestration of cytoplasmic components within double-membrane vesicles termed autophagosomes. The autophagy-related (Atg) protein Atg13 is a key member of the autophagy initiation complex. The Atg13 C terminus is an intrinsically disordered region (IDR) harboring a binding site for the vacuolar membrane protein Vac8. Recent reports suggest Atg13 acts as a hub to assemble the initiation complex, and also participates in membrane recognition. Here we show that the Atg13 C terminus directly binds to lipid membranes via electrostatic interactions between positively charged residues in Atg13 and negatively charged phospholipids as well as a hydrophobic insertion of a Phe residue. We identified 2 sets of residues in the Atg13 IDR that affect its phospholipid-binding properties; these residues overlap with the Vac8-binding domain of Atg13. Our data indicate that Atg13 binding to phospholipids and Vac8 is mutually exclusive, and both are required for efficient autophagy. ABBREVIATIONS Atg: autophagy-related; CD: circular dichroism; Cvt: cytoplasm-to-vacuole targeting; IDR: intrinsically disordered region; ITC: isothermal calorimetry; MIM: MIT-interacting motif; MKO: multiple-knockout; PAS: phagophore assembly site; PC: phosphatidylcholine; PS: phosphatidylserine; PtdIns: phosphatidylinositol; PtdIns3P: phosphatidylinositol-3-phosphate.
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Affiliation(s)
- Damián Gatica
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | | | - Clarence Pascual
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Daniel J. Klionsky
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | | | - Hana Popelka
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
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40
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Nakatogawa H. Mechanisms governing autophagosome biogenesis. Nat Rev Mol Cell Biol 2020; 21:439-458. [PMID: 32372019 DOI: 10.1038/s41580-020-0241-0] [Citation(s) in RCA: 421] [Impact Index Per Article: 105.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2020] [Indexed: 12/20/2022]
Abstract
Autophagosomes are double-membrane vesicles newly formed during autophagy to engulf a wide range of intracellular material and transport this autophagic cargo to lysosomes (or vacuoles in yeasts and plants) for subsequent degradation. Autophagosome biogenesis responds to a plethora of signals and involves unique and dynamic membrane processes. Autophagy is an important cellular mechanism allowing the cell to meet various demands, and its disruption compromises homeostasis and leads to various diseases, including metabolic disorders, neurodegeneration and cancer. Thus, not surprisingly, the elucidation of the molecular mechanisms governing autophagosome biogenesis has attracted considerable interest. Key molecules and organelles involved in autophagosome biogenesis, including autophagy-related (ATG) proteins and the endoplasmic reticulum, have been discovered, and their roles and relationships have been investigated intensely. However, several fundamental questions, such as what supplies membranes/lipids to build the autophagosome and how the membrane nucleates, expands, bends into a spherical shape and finally closes, have proven difficult to address. Nonetheless, owing to recent studies with new approaches and technologies, we have begun to unveil the mechanisms underlying these processes on a molecular level. We now know that autophagosome biogenesis is a highly complex process, in which multiple proteins and lipids from various membrane sources, supported by the formation of membrane contact sites, cooperate with biophysical phenomena, including membrane shaping and liquid-liquid phase separation, to ensure seamless segregation of the autophagic cargo. Together, these studies pave the way to obtaining a holistic view of autophagosome biogenesis.
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Affiliation(s)
- Hitoshi Nakatogawa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
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41
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Martens S, Fracchiolla D. Activation and targeting of ATG8 protein lipidation. Cell Discov 2020; 6:23. [PMID: 32377373 PMCID: PMC7198486 DOI: 10.1038/s41421-020-0155-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/03/2020] [Indexed: 12/19/2022] Open
Abstract
ATG8 family proteins are evolutionary conserved ubiquitin-like modifiers, which become attached to the headgroup of the membrane lipid phosphatidylethanolamine in a process referred to as lipidation. This reaction is carried out analogous to the conjugation of ubiquitin to its target proteins, involving the E1-like ATG7, the E2-like ATG3 and the E3-like ATG12-ATG5-ATG16 complex, which determines the site of lipidation. ATG8 lipidation is a hallmark of autophagy where these proteins are involved in autophagosome formation, the fusion of autophagosomes with lysosomes and cargo selection. However, it has become evident that ATG8 lipidation also occurs in processes that are not directly related to autophagy. Here we discuss recent insights into the targeting of ATG8 lipidation in autophagy and other pathways with special emphasis on the recruitment and activation of the E3-like complex.
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Affiliation(s)
- Sascha Martens
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter, Dr. Bohr-Gasse 9/5, 1030 Vienna, Austria
| | - Dorotea Fracchiolla
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter, Dr. Bohr-Gasse 9/5, 1030 Vienna, Austria
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42
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Sisakht M, Darabian M, Mahmoodzadeh A, Bazi A, Shafiee SM, Mokarram P, Khoshdel Z. The role of radiation induced oxidative stress as a regulator of radio-adaptive responses. Int J Radiat Biol 2020; 96:561-576. [PMID: 31976798 DOI: 10.1080/09553002.2020.1721597] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Purpose: Various sources of radiation including radiofrequency, electromagnetic radiation (EMR), low- dose X-radiation, low-level microwave radiation and ionizing radiation (IR) are indispensable parts of modern life. In the current review, we discussed the adaptive responses of biological systems to radiation with a focus on the impacts of radiation-induced oxidative stress (RIOS) and its molecular downstream signaling pathways.Materials and methods: A comprehensive search was conducted in Web of Sciences, PubMed, Scopus, Google Scholar, Embase, and Cochrane Library. Keywords included Mesh terms of "radiation," "electromagnetic radiation," "adaptive immunity," "oxidative stress," and "immune checkpoints." Manuscripts published up until December 2019 were included.Results: RIOS induces various molecular adaptors connected with adaptive responses in radiation exposed cells. One of these adaptors includes p53 which promotes various cellular signaling pathways. RIOS also activates the intrinsic apoptotic pathway by depolarization of the mitochondrial membrane potential and activating the caspase apoptotic cascade. RIOS is also involved in radiation-induced proliferative responses through interaction with mitogen-activated protein kinases (MAPks) including p38 MAPK, ERK, and c-Jun N-terminal kinase (JNK). Protein kinase B (Akt)/phosphoinositide 3-kinase (PI3K) signaling pathway has also been reported to be involved in RIOS-induced proliferative responses. Furthermore, RIOS promotes genetic instability by introducing DNA structural and epigenetic alterations, as well as attenuating DNA repair mechanisms. Inflammatory transcription factors including macrophage migration inhibitory factor (MIF), nuclear factor κB (NF-κB), and signal transducer and activator of transcription-3 (STAT-3) paly major role in RIOS-induced inflammation.Conclusion: In conclusion, RIOS considerably contributes to radiation induced adaptive responses. Other possible molecular adaptors modulating RIOS-induced responses are yet to be divulged in future studies.
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Affiliation(s)
- Mohsen Sisakht
- Department of Medical Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Maryam Darabian
- Department of Radiology, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amir Mahmoodzadeh
- Department of Medical Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.,Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ali Bazi
- Faculty of Allied Medical Sciences, Zabol University of Medical Sciences, Zabol, Iran
| | - Sayed Mohammad Shafiee
- Department of Medical Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Pooneh Mokarram
- Department of Medical Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Khoshdel
- Department of Medical Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
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43
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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: 21] [Impact Index Per Article: 5.3] [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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44
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Herhaus L, Bhaskara RM, Lystad AH, Gestal‐Mato U, Covarrubias‐Pinto A, Bonn F, Simonsen A, Hummer G, Dikic I. TBK1-mediated phosphorylation of LC3C and GABARAP-L2 controls autophagosome shedding by ATG4 protease. EMBO Rep 2020; 21:e48317. [PMID: 31709703 PMCID: PMC6945063 DOI: 10.15252/embr.201948317] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 10/08/2019] [Accepted: 10/15/2019] [Indexed: 12/22/2022] Open
Abstract
Autophagy is a highly conserved catabolic process through which defective or otherwise harmful cellular components are targeted for degradation via the lysosomal route. Regulatory pathways, involving post-translational modifications such as phosphorylation, play a critical role in controlling this tightly orchestrated process. Here, we demonstrate that TBK1 regulates autophagy by phosphorylating autophagy modifiers LC3C and GABARAP-L2 on surface-exposed serine residues (LC3C S93 and S96; GABARAP-L2 S87 and S88). This phosphorylation event impedes their binding to the processing enzyme ATG4 by destabilizing the complex. Phosphorylated LC3C/GABARAP-L2 cannot be removed from liposomes by ATG4 and are thus protected from ATG4-mediated premature removal from nascent autophagosomes. This ensures a steady coat of lipidated LC3C/GABARAP-L2 throughout the early steps in autophagosome formation and aids in maintaining a unidirectional flow of the autophagosome to the lysosome. Taken together, we present a new regulatory mechanism of autophagy, which influences the conjugation and de-conjugation of LC3C and GABARAP-L2 to autophagosomes by TBK1-mediated phosphorylation.
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Affiliation(s)
- Lina Herhaus
- Institute of Biochemistry IISchool of MedicineGoethe UniversityFrankfurt am MainGermany
| | - Ramachandra M Bhaskara
- Department of Theoretical BiophysicsMax Planck Institute of BiophysicsFrankfurt am MainGermany
| | - Alf Håkon Lystad
- Department of Molecular MedicineFaculty of MedicineInstitute of Basic Medical Sciences and Centre for Cancer Cell ReprogrammingInstitute of Clinical MedicineUniversity of OsloOsloNorway
| | - Uxía Gestal‐Mato
- Institute of Biochemistry IISchool of MedicineGoethe UniversityFrankfurt am MainGermany
| | | | - Florian Bonn
- Institute of Biochemistry IISchool of MedicineGoethe UniversityFrankfurt am MainGermany
- Present address:
Immundiagnostik AGBensheimGermany
| | - Anne Simonsen
- Department of Molecular MedicineFaculty of MedicineInstitute of Basic Medical Sciences and Centre for Cancer Cell ReprogrammingInstitute of Clinical MedicineUniversity of OsloOsloNorway
| | - Gerhard Hummer
- Department of Theoretical BiophysicsMax Planck Institute of BiophysicsFrankfurt am MainGermany
- Institute for BiophysicsGoethe UniversityFrankfurt am MainGermany
| | - Ivan Dikic
- Institute of Biochemistry IISchool of MedicineGoethe UniversityFrankfurt am MainGermany
- Buchmann Institute for Molecular Life SciencesRiedberg Campus, Goethe University FrankfurtFrankfurt am MainGermany
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Mizushima N. The ATG conjugation systems in autophagy. Curr Opin Cell Biol 2019; 63:1-10. [PMID: 31901645 DOI: 10.1016/j.ceb.2019.12.001] [Citation(s) in RCA: 259] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/31/2019] [Accepted: 12/02/2019] [Indexed: 02/08/2023]
Abstract
Autophagosome formation and maturation involve the two ubiquitin-like systems: The ATG8 and ATG12 systems. ATG8 (LC3s and gamma-aminobutyric acid receptor-associated proteins in mammals) and ATG12 are covalently conjugated to phosphatidylethanolamine and ATG5, respectively. Although the ATG12 and ATG8 systems were discovered more than 20 years ago, their molecular functions are not fully understood. The aim of this review is to summarize recent findings related to ATG conjugation systems, focusing on current controversies regarding the genetic hierarchy of these systems, interpretation of conjugation-independent alternative macroautophagy, the differences in roles between LC3s and gamma-aminobutyric acid receptor-associated proteins in autophagosome formation and cargo recognition, and evolution of these systems.
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Affiliation(s)
- Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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Agrotis A, Ketteler R. On ATG4B as Drug Target for Treatment of Solid Tumours-The Knowns and the Unknowns. Cells 2019; 9:cells9010053. [PMID: 31878323 PMCID: PMC7016753 DOI: 10.3390/cells9010053] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 12/13/2022] Open
Abstract
Autophagy is an evolutionary conserved stress survival pathway that has been shown to play an important role in the initiation, progression, and metastasis of multiple cancers; however, little progress has been made to date in translation of basic research to clinical application. This is partially due to an incomplete understanding of the role of autophagy in the different stages of cancer, and also to an incomplete assessment of potential drug targets in the autophagy pathway. While drug discovery efforts are on-going to target enzymes involved in the initiation phase of the autophagosome, e.g., unc51-like autophagy activating kinase (ULK)1/2, vacuolar protein sorting 34 (Vps34), and autophagy-related (ATG)7, we propose that the cysteine protease ATG4B is a bona fide drug target for the development of anti-cancer treatments. In this review, we highlight some of the recent advances in our understanding of the role of ATG4B in autophagy and its relevance to cancer, and perform a critical evaluation of ATG4B as a druggable cancer target.
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Agrotis A, von Chamier L, Oliver H, Kiso K, Singh T, Ketteler R. Human ATG4 autophagy proteases counteract attachment of ubiquitin-like LC3/GABARAP proteins to other cellular proteins. J Biol Chem 2019; 294:12610-12621. [PMID: 31315929 PMCID: PMC6709618 DOI: 10.1074/jbc.ac119.009977] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Indexed: 01/01/2023] Open
Abstract
Microtubule-associated protein 1 light chain 3 α (LC3)/GABA type A receptor-associated protein (GABARAP) comprises a family of ubiquitin-like proteins involved in (macro)autophagy, an important intracellular degradation pathway that delivers cytoplasmic material to lysosomes via double-membrane vesicles called autophagosomes. The only currently known cellular molecules covalently modified by LC3/GABARAP are membrane phospholipids such as phosphatidylethanolamine in the autophagosome membrane. Autophagy-related 4 cysteine peptidase (ATG4) proteases process inactive pro-LC3/GABARAP before lipidation, and the same proteases can also deconjugate LC3/GABARAP from lipids. To determine whether LC3/GABARAP has other molecular targets, here we generated a pre-processed LC3B mutant (Q116P) that is resistant to ATG4-mediated deconjugation. Upon expression in human cells and when assessed by immunoblotting under reducing and denaturing conditions, deconjugation-resistant LC3B accumulated in multiple forms and at much higher molecular weights than free LC3B. We observed a similar accumulation when pre-processed versions of all mammalian LC3/GABARAP isoforms were expressed in ATG4-deficient cell lines, suggesting that LC3/GABARAP can attach also to other larger molecules. We identified ATG3, the E2-like enzyme involved in LC3/GABARAP lipidation, as one target of conjugation with multiple copies of LC3/GABARAP. We show that LC3B-ATG3 conjugates are distinct from the LC3B-ATG3 thioester intermediate formed before lipidation, and we biochemically demonstrate that ATG4B can cleave LC3B-ATG3 conjugates. Finally, we determined ATG3 residue Lys-243 as an LC3B modification site. Overall, we provide the first cellular evidence that mammalian LC3/GABARAP post-translationally modifies proteins akin to ubiquitination ("LC3ylation"), with ATG4 proteases acting like deubiquitinating enzymes to counteract this modification ("deLC3ylation").
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Affiliation(s)
- Alexander Agrotis
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Lucas von Chamier
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Harriet Oliver
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Koshiro Kiso
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Tanya Singh
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Robin Ketteler
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
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48
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Abstract
Autophagy is a highly conserved catabolic process induced under various conditions of cellular stress, which prevents cell damage and promotes survival in the event of energy or nutrient shortage and responds to various cytotoxic insults. Thus, autophagy has primarily cytoprotective functions and needs to be tightly regulated to respond correctly to the different stimuli that cells experience, thereby conferring adaptation to the ever-changing environment. It is now apparent that autophagy is deregulated in the context of various human pathologies, including cancer and neurodegeneration, and its modulation has considerable potential as a therapeutic approach.
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Affiliation(s)
- Ivan Dikic
- Institute of Biochemistry II, School of Medicine, Goethe University, Frankfurt am Main, Germany. .,Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt am Main, Germany.
| | - Zvulun Elazar
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
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Das CK, Banerjee I, Mandal M. Pro-survival autophagy: An emerging candidate of tumor progression through maintaining hallmarks of cancer. Semin Cancer Biol 2019; 66:59-74. [PMID: 31430557 DOI: 10.1016/j.semcancer.2019.08.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/30/2019] [Accepted: 08/16/2019] [Indexed: 12/13/2022]
Abstract
Autophagy is an evolutionary conserved catabolic process that regulates the cellular homeostasis by targeting damaged cellular contents and organelles for lysosomal degradation and sustains genomic integrity, cellular metabolism, and cell survival during diverse stress and adverse conditions. Recently, the role of autophagy is extremely debated in the regulation of cancer initiation and progression. Although autophagy has a dichotomous role in the regulation of cancer, growing numbers of studies largely indicate the pro-survival role of autophagy in cancer progression and metastasis. In this review, we discuss the detailed mechanisms of autophagy, the role of pro-survival autophagy that positively drives several classical as well as emerging hallmarks of cancer for tumorigenic progression, and also we address various autophagy inhibitors that could be harnessed against pro-survival autophagy for effective cancer therapeutics. Finally, we highlight some outstanding problems that need to be deciphered extensively in the future to unravel the role of autophagy in tumor progression.
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Affiliation(s)
- Chandan Kanta Das
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
| | - Indranil Banerjee
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
| | - Mahitosh Mandal
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India.
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Agrotis A, Pengo N, Burden JJ, Ketteler R. Redundancy of human ATG4 protease isoforms in autophagy and LC3/GABARAP processing revealed in cells. Autophagy 2019; 15:976-997. [PMID: 30661429 PMCID: PMC6526816 DOI: 10.1080/15548627.2019.1569925] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Macroautophagy/autophagy is a cellular degradation pathway that delivers cytoplasmic material to lysosomes via double-membrane organelles called autophagosomes. Lipidation of ubiquitin-like LC3/GABARAP proteins on the autophagosome membrane is important for autophagy. The cysteine protease ATG4 executes 2 LC3/GABARAP processing events: priming of newly synthesized pro-LC3/GABARAP to enable subsequent lipidation, and delipidation/deconjugation of lipidated LC3/GABARAP (the exact purpose of which is unclear in mammals). Four ATG4 isoforms (ATG4A to ATG4D) exist in mammals; however, the functional redundancy of these proteins in cells is poorly understood. Here we show that human HAP1 and HeLa cells lacking ATG4B exhibit a severe but incomplete defect in LC3/GABARAP processing and autophagy. By further genetic depletion of ATG4 isoforms using CRISPR-Cas9 and siRNA we uncover that ATG4A, ATG4C and ATGD all contribute to residual priming activity, which is sufficient to enable lipidation of endogenous GABARAPL1 on autophagic structures. We also demonstrate that expressing high levels of pre-primed LC3B in ATG4-deficient cells can rescue a defect in autophagic degradation of the cargo receptor SQSTM1/p62, suggesting that delipidation by human ATG4 is not essential for autophagosome formation and fusion with lysosomes. Overall, our study provides a comprehensive characterization of ATG4 isoform function during autophagy in human cells. Abbreviations: Atg: autophagy-related; baf A1: bafilomycin A1; CASP3: caspase 3; CLEM: correlative light and electron microscopy; CMV: cytomegalovirus; CRISPR: clustered regularly interspaced short palindromic repeats; DKO: double knockout; EGFP: enhanced green fluorescent protein; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor-associated protein like 1; GABARAPL2: GABA type A receptor-associated protein like 2; GFP: green fluorescent protein; HB: homogenization buffer; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LIR: LC3 interacting region; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MFN2: mitofusin 2; N.A.: numerical aperture; NEM: N-ethylmaleimide; PDHA1: pyruvate dehydrogenase E1 alpha 1 subunit; PLD: phospholipase D; PE: phosphatidylethanolamine; RLUC: Renilla luciferase; SQSTM1: sequestosome 1; TEM: transmission electron microscopy; TKO: triple knockout; ULK1: unc-51 like autophagy activating kinase 1; VCL: vinculin; WT: wild-type
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Affiliation(s)
- Alexander Agrotis
- a MRC Laboratory for Molecular Cell Biology , University College London , London , UK
| | - Niccolo Pengo
- a MRC Laboratory for Molecular Cell Biology , University College London , London , UK
| | - Jemima J Burden
- a MRC Laboratory for Molecular Cell Biology , University College London , London , UK
| | - Robin Ketteler
- a MRC Laboratory for Molecular Cell Biology , University College London , London , UK
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