51
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Jimenez-Moreno N, Salomo-Coll C, Murphy LC, Wilkinson S. Signal-Retaining Autophagy Indicator as a Quantitative Imaging Method for ER-Phagy. Cells 2023; 12:1134. [PMID: 37190043 PMCID: PMC10136497 DOI: 10.3390/cells12081134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/24/2023] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
Autophagy is an intracellular lysosomal degradation pathway by which cytoplasmic cargoes are removed to maintain cellular homeostasis. Monitoring autophagy flux is crucial to understand the autophagy process and its biological significance. However, assays to measure autophagy flux are either complex, low throughput or not sensitive enough for reliable quantitative results. Recently, ER-phagy has emerged as a physiologically relevant pathway to maintain ER homeostasis but the process is poorly understood, highlighting the need for tools to monitor ER-phagy flux. In this study, we validate the use of the signal-retaining autophagy indicator (SRAI), a fixable fluorescent probe recently generated and described to detect mitophagy, as a versatile, sensitive and convenient probe for monitoring ER-phagy. This includes the study of either general selective degradation of the endoplasmic reticulum (ER-phagy) or individual forms of ER-phagy involving specific cargo receptors (e.g., FAM134B, FAM134C, TEX264 and CCPG1). Crucially, we present a detailed protocol for the quantification of autophagic flux using automated microscopy and high throughput analysis. Overall, this probe provides a reliable and convenient tool for the measurement of ER-phagy.
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Affiliation(s)
- Natalia Jimenez-Moreno
- Cancer Research UK Scotland Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XR, UK; (C.S.-C.); (S.W.)
| | - Carla Salomo-Coll
- Cancer Research UK Scotland Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XR, UK; (C.S.-C.); (S.W.)
| | - Laura C. Murphy
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK;
| | - Simon Wilkinson
- Cancer Research UK Scotland Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XR, UK; (C.S.-C.); (S.W.)
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52
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Liu L, Tang Y, Zhou Z, Huang Y, Zhang R, Lyu H, Xiao S, Guo D, Ali DW, Michalak M, Chen XZ, Zhou C, Tang J. Membrane Curvature: The Inseparable Companion of Autophagy. Cells 2023; 12:1132. [PMID: 37190041 PMCID: PMC10136490 DOI: 10.3390/cells12081132] [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: 12/07/2022] [Revised: 04/06/2023] [Accepted: 04/10/2023] [Indexed: 05/17/2023] Open
Abstract
Autophagy is a highly conserved recycling process of eukaryotic cells that degrades protein aggregates or damaged organelles with the participation of autophagy-related proteins. Membrane bending is a key step in autophagosome membrane formation and nucleation. A variety of autophagy-related proteins (ATGs) are needed to sense and generate membrane curvature, which then complete the membrane remodeling process. The Atg1 complex, Atg2-Atg18 complex, Vps34 complex, Atg12-Atg5 conjugation system, Atg8-phosphatidylethanolamine conjugation system, and transmembrane protein Atg9 promote the production of autophagosomal membranes directly or indirectly through their specific structures to alter membrane curvature. There are three common mechanisms to explain the change in membrane curvature. For example, the BAR domain of Bif-1 senses and tethers Atg9 vesicles to change the membrane curvature of the isolation membrane (IM), and the Atg9 vesicles are reported as a source of the IM in the autophagy process. The amphiphilic helix of Bif-1 inserts directly into the phospholipid bilayer, causing membrane asymmetry, and thus changing the membrane curvature of the IM. Atg2 forms a pathway for lipid transport from the endoplasmic reticulum to the IM, and this pathway also contributes to the formation of the IM. In this review, we introduce the phenomena and causes of membrane curvature changes in the process of macroautophagy, and the mechanisms of ATGs in membrane curvature and autophagosome membrane formation.
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Affiliation(s)
- Lei Liu
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, China
| | - Yu Tang
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, China
| | - Zijuan Zhou
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
- National “111” Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, China
| | - Yuan Huang
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Rui Zhang
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Hao Lyu
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Shuai Xiao
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Dong Guo
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Declan William Ali
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Xing-Zhen Chen
- Membrane Protein Disease Research Group, Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Cefan Zhou
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
| | - Jingfeng Tang
- Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China
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53
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Ishii S, Chino H, Ode KL, Kurikawa Y, Ueda HR, Matsuura A, Mizushima N, Itakura E. CCPG1 recognizes endoplasmic reticulum luminal proteins for selective ER-phagy. Mol Biol Cell 2023; 34:ar29. [PMID: 36735498 PMCID: PMC10092646 DOI: 10.1091/mbc.e22-09-0432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The endoplasmic reticulum (ER) is a major cell compartment where protein synthesis, folding, and posttranslational modifications occur with assistance from a wide variety of chaperones and enzymes. Quality control systems selectively eliminate abnormal proteins that accumulate inside the ER due to cellular stresses. ER-phagy, that is, selective autophagy of the ER, is a mechanism that maintains or reestablishes cellular and ER-specific homeostasis through removal of abnormal proteins. However, how ER luminal proteins are recognized by the ER-phagy machinery remains unclear. Here, we applied the aggregation-prone protein, six-repeated islet amyloid polypeptide (6xIAPP), as a model ER-phagy substrate and found that cell cycle progression 1 (CCPG1), which is an ER-phagy receptor, efficiently mediates its degradation via ER-phagy. We also identified prolyl 3-hydroxylase family member 4 (P3H4) as an endogenous cargo of CCPG1-dependent ER-phagy. The ER luminal region of CCPG1 contains several highly conserved regions that we refer to as cargo-interacting regions (CIRs); these interact directly with specific luminal cargos for ER-phagy. Notably, 6xIAPP and P3H4 interact directly with different CIRs. These findings indicate that CCPG1 is a bispecific ER-phagy receptor for ER luminal proteins and the autophagosomal membrane that contributes to the efficient removal of aberrant ER-resident proteins through ER-phagy.
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Affiliation(s)
- Shunsuke Ishii
- Department of Biology, Graduate School of Science and Engineering, Chiba University, Chiba 263-8522, Japan
| | - Haruka Chino
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, Tokyo 113-0033, Japan
| | - Koji L Ode
- Department of Systems Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
| | - Yoshitaka Kurikawa
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, Tokyo 113-0033, Japan
| | - Hiroki R Ueda
- Department of Systems Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan.,Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Osaka 565-0871, Japan
| | - Akira Matsuura
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, Tokyo 113-0033, Japan
| | - Eisuke Itakura
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
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54
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Ke PY. Crosstalk between Autophagy and RLR Signaling. Cells 2023; 12:cells12060956. [PMID: 36980296 PMCID: PMC10047499 DOI: 10.3390/cells12060956] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Autophagy plays a homeostatic role in regulating cellular metabolism by degrading unwanted intracellular materials and acts as a host defense mechanism by eliminating infecting pathogens, such as viruses. Upon viral infection, host cells often activate retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling to induce the transcription of type I interferons, thus establishing the first line of the innate antiviral response. In recent years, numerous studies have shown that virus-mediated autophagy activation may benefit viral replication through different actions on host cellular processes, including the modulation of RLR-mediated innate immunity. Here, an overview of the functional molecules and regulatory mechanism of the RLR antiviral immune response as well as autophagy is presented. Moreover, a summary of the current knowledge on the biological role of autophagy in regulating RLR antiviral signaling is provided. The molecular mechanisms underlying the crosstalk between autophagy and RLR innate immunity are also discussed.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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55
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Fricke AL, Mühlhäuser WWD, Reimann L, Zimmermann JP, Reichenbach C, Knapp B, Peikert CD, Heberle AM, Faessler E, Schäuble S, Hahn U, Thedieck K, Radziwill G, Warscheid B. Phosphoproteomics Profiling Defines a Target Landscape of the Basophilic Protein Kinases AKT, S6K, and RSK in Skeletal Myotubes. J Proteome Res 2023; 22:768-789. [PMID: 36763541 DOI: 10.1021/acs.jproteome.2c00505] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Phosphorylation-dependent signal transduction plays an important role in regulating the functions and fate of skeletal muscle cells. Central players in the phospho-signaling network are the protein kinases AKT, S6K, and RSK as part of the PI3K-AKT-mTOR-S6K and RAF-MEK-ERK-RSK pathways. However, despite their functional importance, knowledge about their specific targets is incomplete because these kinases share the same basophilic substrate motif RxRxxp[ST]. To address this, we performed a multifaceted quantitative phosphoproteomics study of skeletal myotubes following kinase inhibition. Our data corroborate a cross talk between AKT and RAF, a negative feedback loop of RSK on ERK, and a putative connection between RSK and PI3K signaling. Altogether, we report a kinase target landscape containing 49 so far unknown target sites. AKT, S6K, and RSK phosphorylate numerous proteins involved in muscle development, integrity, and functions, and signaling converges on factors that are central for the skeletal muscle cytoskeleton. Whereas AKT controls insulin signaling and impinges on GTPase signaling, nuclear signaling is characteristic for RSK. Our data further support a role of RSK in glucose metabolism. Shared targets have functions in RNA maturation, stability, and translation, which suggests that these basophilic kinases establish an intricate signaling network to orchestrate and regulate processes involved in translation.
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Affiliation(s)
- Anna L Fricke
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.,Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Wignand W D Mühlhäuser
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Lena Reimann
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Johannes P Zimmermann
- Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Christa Reichenbach
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Bettina Knapp
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Christian D Peikert
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Alexander M Heberle
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Erik Faessler
- Jena University Language & Information Engineering (JULIE) Lab, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Sascha Schäuble
- Jena University Language & Information Engineering (JULIE) Lab, Friedrich Schiller University Jena, 07743 Jena, Germany.,Systems Biology and Bioinformatics Unit, Leibniz Institute for Natural Product Research and Infection Biology─Leibniz-HKI, 07745 Jena, Germany
| | - Udo Hahn
- Jena University Language & Information Engineering (JULIE) Lab, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Kathrin Thedieck
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria.,Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands.,Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany
| | - Gerald Radziwill
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.,Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
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56
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Vargas JNS, Hamasaki M, Kawabata T, Youle RJ, Yoshimori T. The mechanisms and roles of selective autophagy in mammals. Nat Rev Mol Cell Biol 2023; 24:167-185. [PMID: 36302887 DOI: 10.1038/s41580-022-00542-2] [Citation(s) in RCA: 249] [Impact Index Per Article: 249.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2022] [Indexed: 11/09/2022]
Abstract
Autophagy is a process that targets various intracellular elements for degradation. Autophagy can be non-selective - associated with the indiscriminate engulfment of cytosolic components - occurring in response to nutrient starvation and is commonly referred to as bulk autophagy. By contrast, selective autophagy degrades specific targets, such as damaged organelles (mitophagy, lysophagy, ER-phagy, ribophagy), aggregated proteins (aggrephagy) or invading bacteria (xenophagy), thereby being importantly involved in cellular quality control. Hence, not surprisingly, aberrant selective autophagy has been associated with various human pathologies, prominently including neurodegeneration and infection. In recent years, considerable progress has been made in understanding mechanisms governing selective cargo engulfment in mammals, including the identification of ubiquitin-dependent selective autophagy receptors such as p62, NBR1, OPTN and NDP52, which can bind cargo and ubiquitin simultaneously to initiate pathways leading to autophagy initiation and membrane recruitment. This progress opens the prospects for enhancing selective autophagy pathways to boost cellular quality control capabilities and alleviate pathology.
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Affiliation(s)
- Jose Norberto S Vargas
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
- UK Dementia Research Institute, University College London, London, UK
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Maho Hamasaki
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan.
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
| | - Tsuyoshi Kawabata
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Richard J Youle
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan.
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
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57
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Chino H, Mizushima N. ER-Phagy: Quality and Quantity Control of the Endoplasmic Reticulum by Autophagy. Cold Spring Harb Perspect Biol 2023; 15:cshperspect.a041256. [PMID: 35940904 PMCID: PMC9808580 DOI: 10.1101/cshperspect.a041256] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The endoplasmic reticulum (ER) is the largest organelle and has multiple roles in various cellular processes such as protein secretion, lipid synthesis, calcium storage, and organelle biogenesis. The quantity and quality of this organelle are controlled by the ubiquitin-proteasome system and autophagy (termed "ER-phagy"). ER-phagy is defined as the degradation of part of the ER by the vacuole or lysosomes, and there are at least two types of ER-phagy: macro-ER-phagy and micro-ER-phagy. In macro-ER-phagy, ER fragments are enclosed by autophagosomes, which is mediated by ER-phagy receptors. In micro-ER-phagy, a portion of the ER is engulfed directly by the vacuole or lysosomes. In these two pathways, some proteins in the ER lumen can be recognized selectively and subjected to ER-phagy. This review summarizes our current knowledge of ER-phagy, focusing on its membrane dynamics, molecular mechanisms, substrate specificity, and physiological significance.
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Affiliation(s)
- Haruka Chino
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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58
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Cano-Franco S, Ho-Xuan H, Brunello L, Stolz A. Live-Cell High-Throughput Screen for Monitoring Autophagy Flux. Methods Mol Biol 2023; 2706:215-224. [PMID: 37558952 DOI: 10.1007/978-1-0716-3397-7_16] [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] [Indexed: 08/11/2023]
Abstract
Autophagy is a cellular process implicated in the renewal of cellular components and the maintenance of cellular hemostasis and therefore associated with various types of diseases. In addition, autophagy belongs to the stress response pathways and is frequently activated by chemical compounds harboring characteristics of cell toxicity. High-throughput screens analyzing autophagy flux are therefore applied in both, the field of compound identification for targeting autophagy and compound characterization for analyzing compound toxicity. In this chapter, we describe a live-cell, fluorescent-based, high-throughput screening method in 384-well format for the fast and accurate measurement of autophagy flux over time suitable for academic research, pharmacological applications, and drug discovery.
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Affiliation(s)
- Sara Cano-Franco
- Institute of Biochemistry 2, Faculty of Medicine, Goethe University Frankfurt, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Hung Ho-Xuan
- Institute of Biochemistry 2, Faculty of Medicine, Goethe University Frankfurt, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Lorene Brunello
- Institute of Biochemistry 2, Faculty of Medicine, Goethe University Frankfurt, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Alexandra Stolz
- Institute of Biochemistry 2, Faculty of Medicine, Goethe University Frankfurt, Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany.
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59
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Ishimura R, El-Gowily AH, Noshiro D, Komatsu-Hirota S, Ono Y, Shindo M, Hatta T, Abe M, Uemura T, Lee-Okada HC, Mohamed TM, Yokomizo T, Ueno T, Sakimura K, Natsume T, Sorimachi H, Inada T, Waguri S, Noda NN, Komatsu M. The UFM1 system regulates ER-phagy through the ufmylation of CYB5R3. Nat Commun 2022; 13:7857. [PMID: 36543799 PMCID: PMC9772183 DOI: 10.1038/s41467-022-35501-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Protein modification by ubiquitin-like proteins (UBLs) amplifies limited genome information and regulates diverse cellular processes, including translation, autophagy and antiviral pathways. Ubiquitin-fold modifier 1 (UFM1) is a UBL covalently conjugated with intracellular proteins through ufmylation, a reaction analogous to ubiquitylation. Ufmylation is involved in processes such as endoplasmic reticulum (ER)-associated protein degradation, ribosome-associated protein quality control at the ER and ER-phagy. However, it remains unclear how ufmylation regulates such distinct ER-related functions. Here we identify a UFM1 substrate, NADH-cytochrome b5 reductase 3 (CYB5R3), that localizes on the ER membrane. Ufmylation of CYB5R3 depends on the E3 components UFL1 and UFBP1 on the ER, and converts CYB5R3 into its inactive form. Ufmylated CYB5R3 is recognized by UFBP1 through the UFM1-interacting motif, which plays an important role in the further uyfmylation of CYB5R3. Ufmylated CYB5R3 is degraded in lysosomes, which depends on the autophagy-related protein Atg7- and the autophagy-adaptor protein CDK5RAP3. Mutations of CYB5R3 and genes involved in the UFM1 system cause hereditary developmental disorders, and ufmylation-defective Cyb5r3 knock-in mice exhibit microcephaly. Our results indicate that CYB5R3 ufmylation induces ER-phagy, which is indispensable for brain development.
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Affiliation(s)
- Ryosuke Ishimura
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Afnan H El-Gowily
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan
- Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Daisuke Noshiro
- Division of Biological Molecular Mechanisms, Institute for Genetic Medicine, Hokkaido University, Sapporo, 060-0815, Japan
| | - Satoko Komatsu-Hirota
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Yasuko Ono
- Calpain Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, 156-8506, Japan
| | - Mayumi Shindo
- Advanced Technical Support Department, Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, 156-8506, Japan
| | - Tomohisa Hatta
- National Institutes of Advanced Industrial Science and Technology, Biological Information Research Center (JBIRC), Kohtoh-ku, Tokyo, 135-0064, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, Chuo-ku, Niigata, 951-8585, Japan
| | - Takefumi Uemura
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukshima, 960-1295, Japan
| | - Hyeon-Cheol Lee-Okada
- Department of Biochemistry, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Tarek M Mohamed
- Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Takehiko Yokomizo
- Department of Biochemistry, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Takashi Ueno
- Laboratory of Proteomics and Biomolecular Science, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Chuo-ku, Niigata, 951-8585, Japan
| | - Tohru Natsume
- National Institutes of Advanced Industrial Science and Technology, Biological Information Research Center (JBIRC), Kohtoh-ku, Tokyo, 135-0064, Japan
| | - Hiroyuki Sorimachi
- Calpain Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, 156-8506, Japan
| | - Toshifumi Inada
- Division of RNA and gene regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku, 108-8639, Japan
| | - Satoshi Waguri
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukshima, 960-1295, Japan
| | - Nobuo N Noda
- Division of Biological Molecular Mechanisms, Institute for Genetic Medicine, Hokkaido University, Sapporo, 060-0815, Japan
| | - Masaaki Komatsu
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan.
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60
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Jang W, Puchkov D, Samsó P, Liang Y, Nadler-Holly M, Sigrist SJ, Kintscher U, Liu F, Mamchaoui K, Mouly V, Haucke V. Endosomal lipid signaling reshapes the endoplasmic reticulum to control mitochondrial function. Science 2022; 378:eabq5209. [PMID: 36520888 DOI: 10.1126/science.abq5209] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cells respond to fluctuating nutrient supply by adaptive changes in organelle dynamics and in metabolism. How such changes are orchestrated on a cell-wide scale is unknown. We show that endosomal signaling lipid turnover by MTM1, a phosphatidylinositol 3-phosphate [PI(3)P] 3-phosphatase mutated in X-linked centronuclear myopathy in humans, controls mitochondrial morphology and function by reshaping the endoplasmic reticulum (ER). Starvation-induced endosomal recruitment of MTM1 impairs PI(3)P-dependent contact formation between tubular ER membranes and early endosomes, resulting in the conversion of ER tubules into sheets, the inhibition of mitochondrial fission, and sustained oxidative metabolism. Our results unravel an important role for early endosomal lipid signaling in controlling ER shape and, thereby, mitochondrial form and function to enable cells to adapt to fluctuating nutrient environments.
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Affiliation(s)
- Wonyul Jang
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Dmytro Puchkov
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Paula Samsó
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - YongTian Liang
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Michal Nadler-Holly
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Stephan J Sigrist
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Fan Liu
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.,Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Kamel Mamchaoui
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France
| | - Vincent Mouly
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.,Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany.,Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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61
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Liang JR, Corn JE. A CRISPR view on autophagy. Trends Cell Biol 2022; 32:1008-1022. [PMID: 35581059 DOI: 10.1016/j.tcb.2022.04.006] [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: 02/23/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 01/21/2023]
Abstract
Autophagy is a fundamental pathway for the degradation of cytoplasmic content in response to pleiotropic extracellular and intracellular stimuli. Recent advances in the autophagy field have demonstrated that different organelles can also be specifically targeted for autophagy with broad implications on cellular and organismal health. This opens new dimensions in the autophagy field and more unanswered questions on the rationale and underlying mechanisms to degrade different organelles. Functional genomics via clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9-based screening has gained popularity in the autophagy field to understand the common and unique factors that are implicated in the signaling, recognition, and execution of different cargo-specific autophagies. We focus on recent applications of CRISPR-based screens in the autophagy field, their discoveries, and the future directions of autophagy screens.
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Affiliation(s)
- Jin Rui Liang
- Department of Biology, Institute of Molecular Health Sciences, ETH Zürich, 8093, Zürich, Switzerland; Medical Research Council, Protein Phosphorylation & Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
| | - Jacob E Corn
- Department of Biology, Institute of Molecular Health Sciences, ETH Zürich, 8093, Zürich, Switzerland.
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62
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Sing TL, Brar GA, Ünal E. Gametogenesis: Exploring an Endogenous Rejuvenation Program to Understand Cellular Aging and Quality Control. Annu Rev Genet 2022; 56:89-112. [PMID: 35878627 PMCID: PMC9712276 DOI: 10.1146/annurev-genet-080320-025104] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Gametogenesis is a conserved developmental program whereby a diploid progenitor cell differentiates into haploid gametes, the precursors for sexually reproducing organisms. In addition to ploidy reduction and extensive organelle remodeling, gametogenesis naturally rejuvenates the ensuing gametes, leading to resetting of life span. Excitingly, ectopic expression of the gametogenesis-specific transcription factor Ndt80 is sufficient to extend life span in mitotically dividing budding yeast, suggesting that meiotic rejuvenation pathways can be repurposed outside of their natural context. In this review, we highlight recent studies of gametogenesis that provide emerging insight into natural quality control, organelle remodeling, and rejuvenation strategies that exist within a cell. These include selective inheritance, programmed degradation, and de novo synthesis, all of which are governed by the meiotic gene expression program entailing many forms of noncanonical gene regulation. Finally, we highlight critical questions that remain in the field and provide perspective on the implications of gametogenesis research on human health span.
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Affiliation(s)
- Tina L Sing
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA;
| | - Gloria A Brar
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA;
| | - Elçin Ünal
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA;
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63
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Cherubini A, Zito E. ER stress as a trigger of UPR and ER-phagy in cancer growth and spread. Front Oncol 2022; 12:997235. [PMID: 36408145 PMCID: PMC9667062 DOI: 10.3389/fonc.2022.997235] [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: 07/18/2022] [Accepted: 10/12/2022] [Indexed: 01/25/2023] Open
Abstract
Tumors can survive environmental and metabolic stress by triggering homeostatic responses that re-establish the pre-stress status and permit them to grow and thrive. The endoplasmic reticulum (ER) is the organelle where proteins undergo post-translational modifications and are folded and exported to the secretory pathway. Its environment and activity are therefore fundamental for proteostasis, i.e., the plethora of mechanisms controlling protein formation, folding, degradation, and secretion, needed to assure protein balance and cellular health. In different tumor-related conditions, such as after the activation of oncogenes or under hypoxia and nutrient deprivation, the ER experiences stress, triggered by a high load of proteins to be folded compared to the limited folding capacity of the organelle. As a consequence, three ER membrane sensors and the related unfolded protein response (UPR) are activated. The UPR comprises a complex interconnection between signal transduction pathways that promote a homeostatic response that acts by increasing the amount of protein chaperones and of proteins involved in ER-associated protein degradation (ERAD) on one hand and attenuating protein translation on the other. ER-phagy, literally "eating" the ER, is part of another homeostatic response consisting of the clearance of non-functional ER portions including misfolded proteins. This response is also activated by a set of dedicated ER-phagy receptors after ER stimuli, which overlap the stimuli generating ER stress. Thus, the UPR and ER-phagy are two closely related homeostatic mechanisms that cooperate in re-establishing ER homeostasis. However, while the role of the UPR in favoring cancer growth and thriving by promoting angiogenesis, metastasis, chemotherapy resistance, and epithelial-to-mesenchymal transition is consolidated, that of ER-phagy is still in its infancy. This essay provides an overview of emerging concepts on ER stress, the UPR, and ER-phagy and their crosstalk in tumorigenesis. We also critically review new findings on their pharmacological targeting in cancer.
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Affiliation(s)
- Alessandro Cherubini
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy,Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Ester Zito
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy,Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy,*Correspondence: Ester Zito,
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64
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Sanz-Martinez P, Stolz A. Mechanisms and physiological functions of ER-phagy. CURRENT OPINION IN PHYSIOLOGY 2022. [DOI: 10.1016/j.cophys.2022.100613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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65
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Popelka H, Klionsky DJ. When acidic residues do not mimic phosphorylation: high-affinity binding of the reticulophagy receptor TEX264 to LC3/GABARAP. Autophagy 2022; 18:2515-2518. [PMID: 36041015 PMCID: PMC9629098 DOI: 10.1080/15548627.2022.2119350] [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] [Indexed: 12/15/2022] Open
Abstract
Substrates that are selected for degradation by autophagy interact in more complex eukaryotes with Atg8-family proteins via the LC3-interacting region (LIR) that is often preceded by either acidic residues or phosphorylated serine or threonine. These upstream amino acid residues increase the binding affinity of the LIR motif to its binding site on the surface of LC3/GABARAP. It is not fully understood whether or how phosphorylation functionally replaces acidic residues in the LIR-Atg8-family protein interactions. A recent study by Chino et al. discussed in this article analyzed the phosphorylation of two serine residues upstream of the LIR motif in TEX264, a reticulophagy receptor that exhibits a high binding affinity to LC3/GABARAP proteins. The authors found a structural basis for the high-affinity interaction yielded by phosphorylation but not by an acidic residue in place of phosphoserine. Furthermore, finding that phosphorylation of TEX264 generates its high binding affinity to Atg8-family proteins uncovers a mechanistic alternative to that utilized by other reticulophagy receptors when they interact with LC3/GABARAP.Abbreviations: CSNK2: casein kinase 2; ER: endoplasmic reticulum; IDPR: intrinsically disordered protein region; LIR: LC3-interacting region; p-S: phosphorylated serine.
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Affiliation(s)
- Hana Popelka
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Daniel J Klionsky
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
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66
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Ma X, Li P, Ge L. Targeting of biomolecular condensates to the autophagy pathway. Trends Cell Biol 2022; 33:505-516. [PMID: 36150962 DOI: 10.1016/j.tcb.2022.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/29/2022] [Accepted: 08/29/2022] [Indexed: 10/14/2022]
Abstract
Biomolecular condensates are membraneless compartments formed by liquid-liquid phase separation. They can phase transit into gel-like and solid states. The amount and state of biomolecular condensates must be tightly regulated to maintain normal cellular function. Autophagy targets biomolecular condensates to the lysosome for degradation or other purposes, which we term biocondensophagy. In biocondensophagy, autophagy receptors recognize biomolecular condensates and target them to the autophagosome, the vesicle carrier of autophagy. Multiple types of autophagy receptors have been identified and they are specifically involved in targeting biomolecular condensates with different phase transition states. The receptors also organize the phase transition of biomolecular condensate to facilitate biocondensophagy. Here, we briefly discuss the latest discoveries regarding how biomolecular condensates are recognized by autophagy receptors.
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Affiliation(s)
- Xinyu Ma
- State Key Laboratory of Membrane Biology, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China; School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Pilong Li
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China; School of Life Sciences, Tsinghua University, Beijing, 100084, China; Beijing Advanced Innovation Center for Structural Biology and Frontier Research Center for Biological Structure, Beijing, 100084, China
| | - Liang Ge
- State Key Laboratory of Membrane Biology, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China; School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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67
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Di Lorenzo G, Iavarone F, Maddaluno M, Plata-Gómez AB, Aureli S, Quezada Meza CP, Cinque L, Palma A, Reggio A, Cirillo C, Sacco F, Stolz A, Napolitano G, Marin O, Pinna LA, Ruzzene M, Limongelli V, Efeyan A, Grumati P, Settembre C. Phosphorylation of FAM134C by CK2 controls starvation-induced ER-phagy. SCIENCE ADVANCES 2022; 8:eabo1215. [PMID: 36044577 PMCID: PMC9432840 DOI: 10.1126/sciadv.abo1215] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 07/20/2022] [Indexed: 05/28/2023]
Abstract
Selective degradation of the endoplasmic reticulum (ER) via autophagy (ER-phagy) is initiated by ER-phagy receptors, which facilitate the incorporation of ER fragments into autophagosomes. FAM134 reticulon family proteins (FAM134A, FAM134B, and FAM134C) are ER-phagy receptors with structural similarities and nonredundant functions. Whether they respond differentially to the stimulation of ER-phagy is unknown. Here, we describe an activation mechanism unique to FAM134C during starvation. In fed conditions, FAM134C is phosphorylated by casein kinase 2 (CK2) at critical residues flanking the LIR domain. Phosphorylation of these residues negatively affects binding affinity to the autophagy proteins LC3. During starvation, mTORC1 inhibition limits FAM134C phosphorylation by CK2, hence promoting receptor activation and ER-phagy. Using a novel tool to study ER-phagy in vivo and FAM134C knockout mice, we demonstrated the physiological relevance of FAM134C phosphorylation during starvation-induced ER-phagy in liver lipid metabolism. These data provide a mechanistic insight into ER-phagy regulation and an example of autophagy selectivity during starvation.
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Affiliation(s)
| | | | | | - Ana Belén Plata-Gómez
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Simone Aureli
- Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Euler Institute, Lugano, Switzerland
| | | | - Laura Cinque
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy
| | - Alessandro Palma
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Alessio Reggio
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Carmine Cirillo
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Francesca Sacco
- Department of Biology, University of Rome “Tor Vergata”, Rome, Italy
| | - Alexandra Stolz
- Institute of Biochemistry II, Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University, Frankfurt am Main, Germany
| | - Gennaro Napolitano
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Department of Translational Medicine, Federico II University, Naples, Italy
| | - Oriano Marin
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lorenzo A. Pinna
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- CNR Neuroscience Institute, Padova, Italy
| | - Maria Ruzzene
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- CNR Neuroscience Institute, Padova, Italy
| | - Vittorio Limongelli
- Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Euler Institute, Lugano, Switzerland
- Department of Pharmacy, Federico II University, Naples, Italy
| | - Alejo Efeyan
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Paolo Grumati
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy
| | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy
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68
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Mochida K, Nakatogawa H. ER
‐phagy: selective autophagy of the endoplasmic reticulum. EMBO Rep 2022; 23:e55192. [PMID: 35758175 PMCID: PMC9346472 DOI: 10.15252/embr.202255192] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/24/2022] [Accepted: 06/08/2022] [Indexed: 12/22/2022] Open
Abstract
Eukaryotic cells adequately control the mass and functions of organelles in various situations. Autophagy, an intracellular degradation system, largely contributes to this organelle control by degrading the excess or defective portions of organelles. The endoplasmic reticulum (ER) is an organelle with distinct structural domains associated with specific functions. The ER dynamically changes its mass, components, and shape in response to metabolic, developmental, or proteotoxic cues to maintain or regulate its functions. Therefore, elaborate mechanisms are required for proper degradation of the ER. Here, we review our current knowledge on diverse mechanisms underlying selective autophagy of the ER, which enable efficient degradation of specific ER subdomains according to different demands of cells.
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Affiliation(s)
- Keisuke Mochida
- School of Life Science and Technology Tokyo Institute of Technology Yokohama Japan
| | - Hitoshi Nakatogawa
- School of Life Science and Technology Tokyo Institute of Technology Yokohama Japan
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69
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Gentile D, Esposito M, Grumati P. Metabolic adaption of cancer cells toward autophagy: Is there a role for ER-phagy? Front Mol Biosci 2022; 9:930223. [PMID: 35992272 PMCID: PMC9382244 DOI: 10.3389/fmolb.2022.930223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/04/2022] [Indexed: 11/13/2022] Open
Abstract
Autophagy is an evolutionary conserved catabolic pathway that uses a unique double-membrane vesicle, called autophagosome, to sequester cytosolic components, deliver them to lysosomes and recycle amino-acids. Essentially, autophagy acts as a cellular cleaning system that maintains metabolic balance under basal conditions and helps to ensure nutrient viability under stress conditions. It is also an important quality control mechanism that removes misfolded or aggregated proteins and mediates the turnover of damaged and obsolete organelles. In this regard, the idea that autophagy is a non-selective bulk process is outdated. It is now widely accepted that forms of selective autophagy are responsible for metabolic rewiring in response to cellular demand. Given its importance, autophagy plays an essential role during tumorigenesis as it sustains malignant cellular growth by acting as a coping-mechanisms for intracellular and environmental stress that occurs during malignant transformation. Cancer development is accompanied by the formation of a peculiar tumor microenvironment that is mainly characterized by hypoxia (oxygen < 2%) and low nutrient availability. Such conditions challenge cancer cells that must adapt their metabolism to survive. Here we review the regulation of autophagy and selective autophagy by hypoxia and the crosstalk with other stress response mechanisms, such as UPR. Finally, we discuss the emerging role of ER-phagy in sustaining cellular remodeling and quality control during stress conditions that drive tumorigenesis.
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Affiliation(s)
- Debora Gentile
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Marianna Esposito
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
- Scuola Superiore Meridionale, Naples, Italy
| | - Paolo Grumati
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy
- *Correspondence: Paolo Grumati,
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70
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Autophagy-Associated Immunogenic Modulation and Its Applications in Cancer Therapy. Cells 2022; 11:cells11152324. [PMID: 35954167 PMCID: PMC9367255 DOI: 10.3390/cells11152324] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/24/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022] Open
Abstract
Autophagy, a lysosome-mediated cellular degradation pathway, recycles intracellular components to maintain metabolic balance and survival. Autophagy plays an important role in tumor immunotherapy as a “double-edged sword” that can both promote and inhibit tumor progression. Autophagy acts on innate and adaptive immunity and interacts with immune cells to modulate tumor immunotherapy. The discovery of autophagy inducers and autophagy inhibitors also provides new insights for clinical anti-tumor therapy. However, there are also difficulties in the application of autophagy-related regulators, such as low bioavailability and the lack of efficient selectivity. This review focuses on autophagy-related immunogenic regulation and its application in cancer therapy.
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71
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Kennedy A, Ren HY, Madden VJ, Cyr DM. Lysosome docking to WIPI1 rings and ER-connected phagophores occurs during DNAJB12- and GABARAP-dependent selective autophagy of misfolded P23H-rhodopsin. Mol Biol Cell 2022; 33:ar84. [PMID: 35704470 PMCID: PMC9582645 DOI: 10.1091/mbc.e21-10-0505] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We report on how the endoplasmic reticulum (ER)-associated-autophagy pathway (ERAA) delivers P23H-rhodopsin (P23H-R) to the lysosome. P23H-R accumulates in an ERAD-resistant conformation that is stabilized in a detergent-soluble state by DNAJB12 and Hsp70. P23H-R, DNAJB12, and FIP200 colocalize in discrete foci that punctuate the rim of omegasome rings coated by WIPI1. Loss of DNAJB12 function prevents the association of P23H-R containing ER tubules with omegasomes. P23H-R tubules thread through the wall of WIPI1 rings into their central cavity. Transfer of P23H-R from ER-connected phagophores to lysosomes requires GABARAP and is associated with the transient docking of lysosomes to WIPI1 rings. After departure from WIPI1 rings, new patches of P23H-R are seen in the membranes of lysosomes. The absence of GABARAP prevents transfer of P23H-R from phagophores to lysosomes without interfering with docking. These data identify lysosome docking to omegasomes as an important step in the DNAJB12- and GABARAP-dependent autophagic disposal of dominantly toxic P23H-R.
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Affiliation(s)
- Andrew Kennedy
- Department of Cell Biology and Physiology, School of Medicine, and
| | - Hong Yu Ren
- Department of Cell Biology and Physiology, School of Medicine, and
| | - Victoria J. Madden
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Douglas M. Cyr
- Department of Cell Biology and Physiology, School of Medicine, and,*Address correspondence to: Douglas M. Cyr ()
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72
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Compounds activating VCP D1 ATPase enhance both autophagic and proteasomal neurotoxic protein clearance. Nat Commun 2022; 13:4146. [PMID: 35842429 PMCID: PMC9288506 DOI: 10.1038/s41467-022-31905-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 07/08/2022] [Indexed: 01/04/2023] Open
Abstract
Enhancing the removal of aggregate-prone toxic proteins is a rational therapeutic strategy for a number of neurodegenerative diseases, especially Huntington's disease and various spinocerebellar ataxias. Ideally, such approaches should preferentially clear the mutant/misfolded species, while having minimal impact on the stability of wild-type/normally-folded proteins. Furthermore, activation of both ubiquitin-proteasome and autophagy-lysosome routes may be advantageous, as this would allow effective clearance of both monomeric and oligomeric species, the latter which are inaccessible to the proteasome. Here we find that compounds that activate the D1 ATPase activity of VCP/p97 fulfill these requirements. Such effects are seen with small molecule VCP activators like SMER28, which activate autophagosome biogenesis by enhancing interactions of PI3K complex components to increase PI(3)P production, and also accelerate VCP-dependent proteasomal clearance of such substrates. Thus, this mode of VCP activation may be a very attractive target for many neurodegenerative diseases.
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73
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Tex264 Binding to SNX27 Regulates Itgα5 Receptor Membrane Recycling and Affects Cell Migration. BIOMED RESEARCH INTERNATIONAL 2022; 2022:4304419. [PMID: 35837377 PMCID: PMC9274233 DOI: 10.1155/2022/4304419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 06/20/2022] [Indexed: 11/18/2022]
Abstract
Tex264 is an endoplasmic reticulum (ER) membrane protein that was recently demonstrated to act as an ER-phagy receptor under starvation conditions to mediate endoplasmic reticulum autophagy. However, how Tex264 functions in the central nervous system (CNS) and tumors is unclear. Here, we identified 89 proteins from the rat brain that may specifically interact with Tex264 and confirmed the interaction between sorting nexin 27 (SNX27) and Tex264 by coimmunoprecipitation and immunofluorescence. Our results indicated that Tex264 may promote recycling of membrane proteins from endosomes to the cell plasma membrane by recruiting SNX27 retromer vesicles. siRNA-mediated knockdown of TEX264 in HeLa cells did not affect cell proliferation but did significantly inhibit cell migration through a mechanism that may involve a reduction in SNX27-mediated Itgα5 receptor membrane recycling. Results of this study helped identify potential binding Tex264 partners and provide insights into Tex264 functions in the CNS and in tumors.
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74
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Aroca A, Gotor C. Hydrogen sulfide action in the regulation of plant autophagy. FEBS Lett 2022; 596:2186-2197. [PMID: 35735749 DOI: 10.1002/1873-3468.14433] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 05/30/2022] [Accepted: 06/13/2022] [Indexed: 11/09/2022]
Abstract
Hydrogen sulfide is a signaling molecule with a well-established impact on both plant and animal physiology. Intense investigation into the regulation of autophagy by sulfide in Arabidopsis thaliana has revealed that the post-translational modification of persulfidation/S-sulfhydration plays a key role. In this review focused on plants, we discuss the nature of the sulfide molecule involved in the regulation of autophagy, the final outcome of this modification, and the persulfidated autophagy proteins identified so far. A detailed outline of the actual knowledge of the regulation mechanism of the autophagy-related proteins ATG4a and ATG18a from Arabidopsis by sulfide is also included. This information will be instrumental for furthering research on the regulation of autophagy by sulfide.
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Affiliation(s)
- Angeles Aroca
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Seville, Spain
| | - Cecilia Gotor
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Seville, Spain
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75
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Chino H, Yamasaki A, Ode KL, Ueda HR, Noda NN, Mizushima N. Phosphorylation by casein kinase 2 enhances the interaction between ER-phagy receptor TEX264 and ATG8 proteins. EMBO Rep 2022; 23:e54801. [PMID: 35417087 PMCID: PMC9171416 DOI: 10.15252/embr.202254801] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/24/2022] [Accepted: 03/30/2022] [Indexed: 01/03/2023] Open
Abstract
Selective autophagy cargos are recruited to autophagosomes primarily by interacting with autophagosomal ATG8 family proteins via the LC3-interacting region (LIR). The upstream sequence of most LIRs contains negatively charged residues such as Asp, Glu, and phosphorylated Ser and Thr. However, the significance of LIR phosphorylation (compared with having acidic amino acids) and the structural basis of phosphorylated LIR-ATG8 binding are not entirely understood. Here, we show that the serine residues upstream of the core LIR of the endoplasmic reticulum (ER)-phagy receptor TEX264 are phosphorylated by casein kinase 2, which is critical for its interaction with ATG8s, autophagosomal localization, and ER-phagy. Structural analysis shows that phosphorylation of these serine residues increases binding affinity by producing multiple hydrogen bonds with ATG8s that cannot be mimicked by acidic residues. This binding mode is different from those of other ER-phagy receptors that utilize a downstream helix, which is absent from TEX264, to increase affinity. These results suggest that phosphorylation of the LIR is critically important for strong LIR-ATG8 interactions, even in the absence of auxiliary interactions.
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Affiliation(s)
- Haruka Chino
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Akinori Yamasaki
- Institute of Microbial Chemistry (BIKAKEN), Shinagawa-ku, Tokyo, Japan
| | - Koji L Ode
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiroki R Ueda
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Nobuo N Noda
- Institute of Microbial Chemistry (BIKAKEN), Shinagawa-ku, Tokyo, Japan.,Division of Biological Molecular Mechanisms, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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76
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Luong AM, Koestel J, Bhati KK, Batoko H. Cargo receptors and adaptors for selective autophagy in plant cells. FEBS Lett 2022; 596:2104-2132. [PMID: 35638898 DOI: 10.1002/1873-3468.14412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/08/2022] [Accepted: 05/23/2022] [Indexed: 11/06/2022]
Abstract
Plant selective (macro)autophagy is a highly regulated process whereby eukaryotic cells spatiotemporally degrade some of their constituents that have become superfluous or harmful. The identification and characterization of the factors determining this selectivity make it possible to integrate selective (macro)autophagy into plant cell physiology and homeostasis. The specific cargo receptors and/or scaffold proteins involved in this pathway are generally not structurally conserved, as are the biochemical mechanisms underlying recognition and integration of a given cargo into the autophagosome in different cell types. This review discusses the few specific cargo receptors described in plant cells to highlight key features of selective autophagy in the plant kingdom and its integration with plant physiology, so as to identify evolutionary convergence and knowledge gaps to be filled by future research.
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Affiliation(s)
- Ai My Luong
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Jérôme Koestel
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Kaushal Kumar Bhati
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Henri Batoko
- Louvain Institute of Biomolecular Science and Technology, University of Louvain Croix du Sud 4, L7.07.14, 1348, Louvain-la-Neuve, Belgium
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77
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Gubas A, Dikic I. ER remodeling via ER-phagy. Mol Cell 2022; 82:1492-1500. [PMID: 35452617 PMCID: PMC9098120 DOI: 10.1016/j.molcel.2022.02.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/24/2022] [Accepted: 02/09/2022] [Indexed: 01/01/2023]
Abstract
The endoplasmic reticulum (ER) is a hotspot for many essential cellular functions. The ER membrane is highly dynamic, which affects many cellular processes that take place within the ER. One such process is ER-phagy, a selective degradation of ER fragments (including membranes and luminal content), which serves to preserve the size of ER while adapting its morphology under basal and stress conditions. In order to be degraded, the ER undergoes selective fragmentation facilitated by specialized ER-shaping proteins that also act as ER-phagy receptors. Their ability to sense and induce membrane curvature, as well as to bridge the ER with autophagy machinery, allows for a successful ER fragmentation and delivery of these fragments to the lysosome for degradation and recycling. In this review, we provide insights into ER-phagy from the perspective of membrane remodeling. We highlight the importance of ER membrane dynamics during ER-phagy and emphasize how its dysregulation reflects on human physiology and pathology.
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Affiliation(s)
- Andrea Gubas
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, Frankfurt, Germany.
| | - Ivan Dikic
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, Frankfurt, Germany; Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany; Max Planck Institute of Biophysics, Frankfurt, Germany.
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78
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Chipurupalli S, Ganesan R, Martini G, Mele L, Reggio A, Esposito M, Kannan E, Namasivayam V, Grumati P, Desiderio V, Robinson N. Cancer cells adapt FAM134B/BiP mediated ER-phagy to survive hypoxic stress. Cell Death Dis 2022; 13:357. [PMID: 35436985 PMCID: PMC9016075 DOI: 10.1038/s41419-022-04813-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/21/2022] [Accepted: 03/31/2022] [Indexed: 02/06/2023]
Abstract
In the tumor microenvironment, cancer cells experience hypoxia resulting in the accumulation of misfolded/unfolded proteins largely in the endoplasmic reticulum (ER). Consequently, ER proteotoxicity elicits unfolded protein response (UPR) as an adaptive mechanism to resolve ER stress. In addition to canonical UPR, proteotoxicity also stimulates the selective, autophagy-dependent, removal of discrete ER domains loaded with misfolded proteins to further alleviate ER stress. These mechanisms can favor cancer cell growth, metastasis, and long-term survival. Our investigations reveal that during hypoxia-induced ER stress, the ER-phagy receptor FAM134B targets damaged portions of ER into autophagosomes to restore ER homeostasis in cancer cells. Loss of FAM134B in breast cancer cells results in increased ER stress and reduced cell proliferation. Mechanistically, upon sensing hypoxia-induced proteotoxic stress, the ER chaperone BiP forms a complex with FAM134B and promotes ER-phagy. To prove the translational implication of our mechanistic findings, we identified vitexin as a pharmacological agent that disrupts FAM134B-BiP complex, inhibits ER-phagy, and potently suppresses breast cancer progression in vivo.
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Affiliation(s)
- Sandhya Chipurupalli
- Cellular-Stress and Immune Response Laboratory, Center for Cancer Biology, University of South Australia, Adelaide, Australia.,Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Ooty, India.,Departments of Pediatrics & Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Canada
| | - Raja Ganesan
- Cellular-Stress and Immune Response Laboratory, Center for Cancer Biology, University of South Australia, Adelaide, Australia
| | - Giulia Martini
- Medical Oncology, Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Luigi Mele
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Alessio Reggio
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Marianna Esposito
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Elango Kannan
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Ooty, India.,Department of Pharmacology, Faculty of Pharmacy, Karpagam Academy of Higher Education, Coimbatore, India
| | | | - Paolo Grumati
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy.,Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Vincenzo Desiderio
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy.
| | - Nirmal Robinson
- Cellular-Stress and Immune Response Laboratory, Center for Cancer Biology, University of South Australia, Adelaide, Australia.
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79
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Ma X, Lu C, Chen Y, Li S, Ma N, Tao X, Li Y, Wang J, Zhou M, Yan YB, Li P, Heydari K, Deng H, Zhang M, Yi C, Ge L. CCT2 is an aggrephagy receptor for clearance of solid protein aggregates. Cell 2022; 185:1325-1345.e22. [PMID: 35366418 DOI: 10.1016/j.cell.2022.03.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 12/13/2021] [Accepted: 03/01/2022] [Indexed: 12/12/2022]
Abstract
Protein aggregation is a hallmark of multiple human pathologies. Autophagy selectively degrades protein aggregates via aggrephagy. How selectivity is achieved has been elusive. Here, we identify the chaperonin subunit CCT2 as an autophagy receptor regulating the clearance of aggregation-prone proteins in the cell and the mouse brain. CCT2 associates with aggregation-prone proteins independent of cargo ubiquitination and interacts with autophagosome marker ATG8s through a non-classical VLIR motif. In addition, CCT2 regulates aggrephagy independently of the ubiquitin-binding receptors (P62, NBR1, and TAX1BP1) or chaperone-mediated autophagy. Unlike P62, NBR1, and TAX1BP1, which facilitate the clearance of protein condensates with liquidity, CCT2 specifically promotes the autophagic degradation of protein aggregates with little liquidity (solid aggregates). Furthermore, aggregation-prone protein accumulation induces the functional switch of CCT2 from a chaperone subunit to an autophagy receptor by promoting CCT2 monomer formation, which exposes the VLIR to ATG8s interaction and, therefore, enables the autophagic function.
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Affiliation(s)
- Xinyu Ma
- State Key Laboratory of Membrane Biology, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Caijing Lu
- State Key Laboratory of Membrane Biology, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, 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
| | - Shulin Li
- State Key Laboratory of Membrane Biology, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ningjia Ma
- State Key Laboratory of Membrane Biology, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xuan Tao
- State Key Laboratory of Membrane Biology, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ying Li
- State Key Laboratory of Membrane Biology, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jing Wang
- State Key Laboratory of Membrane Biology, Beijing, China; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Min Zhou
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China; Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Beijing 100084, China
| | - Yong-Bin Yan
- State Key Laboratory of Membrane Biology, Beijing, China; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Pilong Li
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China; Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Beijing 100084, China
| | - Kartoosh Heydari
- Cancer Research Laboratory FACS Core Facility, University of California, Berkeley, CA 94720, USA
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Beijing 100084, China; MOE Key Laboratory of Bioinformatics, Beijing, China
| | - Min Zhang
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, 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.
| | - Liang Ge
- State Key Laboratory of Membrane Biology, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China.
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80
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Ghani MJ, Gu W, Chen Z, Canessa CM. Lipid droplets and autophagosomes together with chaperones fine-tune expression of SGK1. J Cell Mol Med 2022; 26:2852-2865. [PMID: 35393773 PMCID: PMC9097849 DOI: 10.1111/jcmm.17300] [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: 08/23/2021] [Revised: 03/05/2022] [Accepted: 03/10/2022] [Indexed: 11/29/2022] Open
Abstract
Serum-glucocorticoid-induced kinase-1 (SGK1) regulates ion homeostasis and promotes survival under stress conditions. The expression of SGK1 is under transcriptional and post-translational regulations that are frequently altered in cancer and immune disorders. We report that an N-terminal amphipathic alpha-helix determines SGK1 expression levels through two distinct mechanisms. It tethers SGK1 to intracellular organelles generating a large pool of membrane-bound SGK1, which is differentially stabilized in lipid droplets (LD) in fed conditions or degraded in the endoplasmic reticulum by ER-phagy in starvation. Association of the α-helix to organelles does not depend on dedicated receptors or special phospholipids rather, it is intrinsic to its physicochemical properties and depends on the presence of bulky hydrophobic residues for attachment to LDs. The second mechanism is recruitment of protein-chaperones that recognize the α-helix as an unfolded protein promoting survival of the cytosolic SGK1 fraction. Together, the findings unveil an unexpected link between levels of energy storage and abundance of SGK1 and how changes in calorie intake could be used to modulate SGK1 expression, whereas the inhibition of molecular chaperones could serve as an additional enhancer in the treatment of malignancies and autoimmune disorders with high levels of SGK1 expression.
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Affiliation(s)
| | - Wenxue Gu
- School of Medicine, Tsinghua University, Beijing, China
| | - Zhuyuan Chen
- School of Medicine, Tsinghua University, Beijing, China
| | - Cecilia M Canessa
- School of Medicine, Tsinghua University, Beijing, China.,Yale School of Medicine, Yale University, New Haven, Connecticut, USA
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81
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Fission Yeast Autophagy Machinery. Cells 2022; 11:cells11071086. [PMID: 35406650 PMCID: PMC8997447 DOI: 10.3390/cells11071086] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [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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82
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ER-phagy in the Occurrence and Development of Cancer. Biomedicines 2022; 10:biomedicines10030707. [PMID: 35327508 PMCID: PMC8945671 DOI: 10.3390/biomedicines10030707] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 02/04/2023] Open
Abstract
As an organelle, the endoplasmic reticulum (ER) is closely related to protein synthesis and modification. When physiological or pathological stimuli induce disorders of ER function, misfolded proteins trigger ER-phagy, which is beneficial for restoring cell homeostasis or promoting cell apoptosis. As a double-edged sword, ER-phagy actively participates in various stages of development and progression in tumor cells, regulating tumorigenesis and maintaining tumor cell homeostasis. Through the unfolded protein response (UPR), the B cell lymphoma 2 (BCL-2) protein family, the Caspase signaling pathway, and others, ER-phagy plays an initiating role in tumor occurrence, migration, stemness, and proliferation. At the same time, many vital proteins strongly associated with ER-phagy, such as family with sequence similarity 134 member B (FAM134B), translocation protein SEC62 (SEC62), and C/EBP-homologous protein (CHOP), can produce a marked effect in many complex environments, which ultimately lead to entirely different tumor fates. Our article comprehensively focused on introducing the relationship and interaction between ER-phagy and cancers, as well as their molecular mechanism and regulatory pathways. Via these analyses, we tried to clarify the possibility of ER-phagy as a potential target for cancer therapy and provide ideas for further research.
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83
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Goldsmith J, Ordureau A, Harper JW, Holzbaur ELF. Brain-derived autophagosome profiling reveals the engulfment of nucleoid-enriched mitochondrial fragments by basal autophagy in neurons. Neuron 2022; 110:967-976.e8. [PMID: 35051374 PMCID: PMC8930448 DOI: 10.1016/j.neuron.2021.12.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/18/2021] [Accepted: 12/16/2021] [Indexed: 12/20/2022]
Abstract
Neurons depend on autophagy to maintain cellular homeostasis, and defects in autophagy are pathological hallmarks of neurodegenerative disease. To probe the role of basal autophagy in the maintenance of neuronal health, we isolated autophagic vesicles from mouse brain tissue and used proteomics to identify the major cargos engulfed within autophagosomes, validating our findings in rodent primary and human iPSC-derived neurons. Mitochondrial proteins were identified as a major cargo in the absence of mitophagy adaptors such as OPTN. We found that nucleoid-associated proteins are enriched compared with other mitochondrial components. In the axon, autophagic engulfment of nucleoid-enriched mitochondrial fragments requires the mitochondrial fission machinery Drp1. We proposed that localized Drp1-dependent fission of nucleoid-enriched fragments in proximity to the sites of autophagosome biogenesis enhances their capture. The resulting efficient autophagic turnover of nucleoids may prevent accumulation of mitochondrial DNA in the neuron, thus mitigating activation of proinflammatory pathways that contribute to neurodegeneration.
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Affiliation(s)
- Juliet Goldsmith
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Alban Ordureau
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - J Wade Harper
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Erika L F Holzbaur
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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84
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Reggiori F, Molinari M. ER-phagy: mechanisms, regulation and diseases connected to the lysosomal clearance of the endoplasmic reticulum. Physiol Rev 2022; 102:1393-1448. [PMID: 35188422 PMCID: PMC9126229 DOI: 10.1152/physrev.00038.2021] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
ER-phagy (reticulo-phagy) defines the degradation of portions of the endoplasmic reticulum (ER) within lysosomes or vacuoles. It is part of the self-digestion (i.e., auto-phagic) programs recycling cytoplasmic material and organelles, which rapidly mobilize metabolites in cells confronted with nutrient shortage. Moreover, selective clearance of ER subdomains participates to the control of ER size and activity during ER stress, the re-establishment of ER homeostasis after ER stress resolution and the removal of ER parts, in which aberrant and potentially cytotoxic material has been segregated. ER-phagy relies on the individual and/or concerted activation of the ER-phagy receptors, ER peripheral or integral membrane proteins that share the presence of LC3/Atg8-binding motifs in their cytosolic domains. ER-phagy involves the physical separation of portions of the ER from the bulk ER network, and their delivery to the endolysosomal/vacuolar catabolic district. This last step is accomplished by a variety of mechanisms including macro-ER-phagy (in which ER fragments are sequestered by double-membrane autophagosomes that eventually fuse with lysosomes/vacuoles), micro-ER-phagy (in which ER fragments are directly engulfed by endosomes/lysosomes/vacuoles), or direct fusion of ER-derived vesicles with lysosomes/vacuoles. ER-phagy is dysfunctional in specific human diseases and its regulators are subverted by pathogens, highlighting its crucial role for cell and organism life.
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Affiliation(s)
- Fulvio Reggiori
- Department of Biomedical Sciences of Cells & Systems, grid.4830.fUniversity of Groningen, Netherlands
| | - Maurizio Molinari
- Protein Folding and Quality Control, grid.7722.0Institute for Research in Biomedicine, Bellinzona, Switzerland
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85
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B B, Zeng Z, Zhou C, Lian G, Guo F, Wang J, Han N, Zhu M, Bian H. Identification of New ATG8s-Binding Proteins with Canonical LC3-Interacting Region in Autophagosomes of Barley Callus. PLANT & CELL PHYSIOLOGY 2022:pcac015. [PMID: 35134996 DOI: 10.1093/pcp/pcac015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Autophagy is essential to maintain cellular homeostasis for normal cell growth and development. In selective autophagy, ATG8 plays a crucial role in cargo target recognition by binding to various adaptors and receptors with the ATG8-interacting motif, also known as the LC3-interacting region (LIR). However, the process of autophagy in the callus, as a proliferating cell type, is largely unknown. In this study, we overexpressed green fluorescent protein (GFP)-ATG8a and GFP-ATG8b transgenic barley callus and checked their autophagic activities. We identified five new ATG8 candidate interactors containing the canonical LIR motif by using immunoprecipitation coupled with mass spectrometry: RPP3, COPE, NCLN, RAE1, and CTSL. The binding activities between these candidate interactors and ATG8 were further demonstrated in the punctate structure. Notably, RPP3 was colocalized in ATG8-labeled autophagosomes under tunicamycin-induced ER stress. GST pull-down assays showed that the interaction between RPP3 and ATG8 could be prevented by mutating the LIRs region of RPP3 or the LIR docking site (LDS) of ATG8, suggesting that RPP3 directly interacted with ATG8 in an LIR-dependent manner via the LDS. Our findings would provide the basis for further investigations on novel receptors and functions of autophagy in plants, especially in the physiological state of cell de-differentiation.
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86
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Duwaerts CC, Maiers JL. ER Disposal Pathways in Chronic Liver Disease: Protective, Pathogenic, and Potential Therapeutic Targets. Front Mol Biosci 2022; 8:804097. [PMID: 35174209 PMCID: PMC8841999 DOI: 10.3389/fmolb.2021.804097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022] Open
Abstract
The endoplasmic reticulum is a central player in liver pathophysiology. Chronic injury to the ER through increased lipid content, alcohol metabolism, or accumulation of misfolded proteins causes ER stress, dysregulated hepatocyte function, inflammation, and worsened disease pathogenesis. A key adaptation of the ER to resolve stress is the removal of excess or misfolded proteins. Degradation of intra-luminal or ER membrane proteins occurs through distinct mechanisms that include ER-associated Degradation (ERAD) and ER-to-lysosome-associated degradation (ERLAD), which includes macro-ER-phagy, micro-ER-phagy, and Atg8/LC-3-dependent vesicular delivery. All three of these processes are critical for removing misfolded or unfolded protein aggregates, and re-establishing ER homeostasis following expansion/stress, which is critical for liver function and adaptation to injury. Despite playing a key role in resolving ER stress, the contribution of these degradative processes to liver physiology and pathophysiology is understudied. Analysis of publicly available datasets from diseased livers revealed that numerous genes involved in ER-related degradative pathways are dysregulated; however, their roles and regulation in disease progression are not well defined. Here we discuss the dynamic regulation of ER-related protein disposal pathways in chronic liver disease and cell-type specific roles, as well as potentially targetable mechanisms for treatment of chronic liver disease.
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Affiliation(s)
- Caroline C. Duwaerts
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Jessica L. Maiers
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States
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87
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Chipurupalli S, Desiderio V, Robinson N. Analysis of ER-Phagy in Cancer Drug Resistance. Methods Mol Biol 2022; 2535:211-220. [PMID: 35867233 DOI: 10.1007/978-1-0716-2513-2_16] [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] [Indexed: 06/15/2023]
Abstract
The ability of the cancer cells to survive hostile environment depends on their cellular stress response mechanisms. These mechanisms also help them to develop resistance to chemotherapies. Autophagy and more specifically organelle specific autophagy is one such adaptive mechanism that promotes drug resistance in cancer cells. Endoplasmic reticulum-specific autophagy or ER-phagy has been more recently described to overcome ER-stress through the degradation of damaged ER. ER-resident proteins such as FAM134B act as ER-phagy receptors to specifically target damaged ER for degradation through autophagy. Moreover, we had recently deciphered that ER-phagy facilitates cancer cell survival during hypoxic stress and we predict that this process could play a critical role in the development of drug resistance in cancer cells. Therefore, here, we provide a lay description of how ER-phagy could be investigated biochemically by Western blot analysis and silencing ER-phagy receptor genes using small interfering RNAs (siRNA).
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Affiliation(s)
- Sandhya Chipurupalli
- Cellular Stress and Immune Response Laboratory, Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
- Departments of Pediatrics & Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS, Canada
| | - Vincenzo Desiderio
- Department of Experimental Medicine, University of Campania "L. Vanvitelli", Naples, Italy
| | - Nirmal Robinson
- Cellular Stress and Immune Response Laboratory, Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia.
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88
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Simoni EB, Oliveira CC, Fraga OT, Reis PAB, Fontes EPB. Cell Death Signaling From Endoplasmic Reticulum Stress: Plant-Specific and Conserved Features. FRONTIERS IN PLANT SCIENCE 2022; 13:835738. [PMID: 35185996 PMCID: PMC8850647 DOI: 10.3389/fpls.2022.835738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/10/2022] [Indexed: 05/06/2023]
Abstract
The endoplasmic reticulum (ER) stress response is triggered by any condition that disrupts protein folding and promotes the accumulation of unfolded proteins in the lumen of the organelle. In eukaryotic cells, the evolutionarily conserved unfolded protein response is activated to clear unfolded proteins and restore ER homeostasis. The recovery from ER stress is accomplished by decreasing protein translation and loading into the organelle, increasing the ER protein processing capacity and ER-associated protein degradation activity. However, if the ER stress persists and cannot be reversed, the chronically prolonged stress leads to cellular dysfunction that activates cell death signaling as an ultimate attempt to survive. Accumulating evidence implicates ER stress-induced cell death signaling pathways as significant contributors for stress adaptation in plants, making modulators of ER stress pathways potentially attractive targets for stress tolerance engineering. Here, we summarize recent advances in understanding plant-specific molecular mechanisms that elicit cell death signaling from ER stress. We also highlight the conserved features of ER stress-induced cell death signaling in plants shared by eukaryotic cells.
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89
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Ordureau A, Kraus F, Zhang J, An H, Park S, Ahfeldt T, Paulo JA, Harper JW. Temporal proteomics during neurogenesis reveals large-scale proteome and organelle remodeling via selective autophagy. Mol Cell 2021; 81:5082-5098.e11. [PMID: 34699746 PMCID: PMC8688335 DOI: 10.1016/j.molcel.2021.10.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/23/2021] [Accepted: 10/01/2021] [Indexed: 12/18/2022]
Abstract
Cell state changes are associated with proteome remodeling to serve newly emergent cell functions. Here, we show that NGN2-driven conversion of human embryonic stem cells to induced neurons (iNeurons) is associated with increased PINK1-independent mitophagic flux that is temporally correlated with metabolic reprogramming to support oxidative phosphorylation. Global multiplex proteomics during neurogenesis revealed large-scale remodeling of functional modules linked with pluripotency, mitochondrial metabolism, and proteostasis. Differentiation-dependent mitophagic flux required BNIP3L and its LC3-interacting region (LIR) motif, and BNIP3L also promoted mitophagy in dopaminergic neurons. Proteomic analysis of ATG12-/- iNeurons revealed accumulation of endoplasmic reticulum, Golgi, and mitochondria during differentiation, indicative of widespread organelle remodeling during neurogenesis. This work reveals broad organelle remodeling of membrane-bound organelles during NGN2-driven neurogenesis via autophagy, identifies BNIP3L's central role in programmed mitophagic flux, and provides a proteomic resource for elucidating how organelle remodeling and autophagy alter the proteome during changes in cell state.
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Affiliation(s)
- Alban Ordureau
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
| | - Felix Kraus
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Jiuchun Zhang
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Heeseon An
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Sookhee Park
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Tim Ahfeldt
- Nash Family Department of Neuroscience at Mount Sinai, New York, NY 10029, USA; Department of Neurology at Mount Sinai, New York, NY 10029, USA; Department of Cell, Developmental and Regenerative Biology at Mount Sinai, New York, NY 10029, USA; Ronald M. Loeb Center for Alzheimer's Disease at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute at Mount Sinai, New York, NY 10029, USA; Black Family Stem Cell Institute at Mount Sinai, New York, NY 10029, USA
| | - Joao A Paulo
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - J Wade Harper
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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90
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Otto GM, Cheunkarndee T, Leslie JM, Brar GA. Programmed cortical ER collapse drives selective ER degradation and inheritance in yeast meiosis. J Cell Biol 2021; 220:212710. [PMID: 34661602 PMCID: PMC8562846 DOI: 10.1083/jcb.202108105] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 09/22/2021] [Accepted: 09/27/2021] [Indexed: 12/24/2022] Open
Abstract
The endoplasmic reticulum (ER) carries out essential and conserved cellular functions, which depend on the maintenance of its structure and subcellular distribution. Here, we report developmentally regulated changes in ER morphology and composition during budding yeast meiosis, a conserved differentiation program that gives rise to gametes. A subset of the cortical ER collapses away from the plasma membrane at anaphase II, thus separating into a spatially distinct compartment. This programmed collapse depends on the transcription factor Ndt80, conserved ER membrane structuring proteins Lnp1 and reticulons, and the actin cytoskeleton. A subset of ER is retained at the mother cell plasma membrane and excluded from gamete cells via the action of ER-plasma membrane tethering proteins. ER remodeling is coupled to ER degradation by selective autophagy, which relies on ER collapse and is regulated by timed expression of the autophagy receptor Atg40. Thus, developmentally programmed changes in ER morphology determine the selective degradation or inheritance of ER subdomains by gametes.
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Affiliation(s)
- George Maxwell Otto
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Tia Cheunkarndee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Jessica Mae Leslie
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Gloria Ann Brar
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA.,Center for Computational Biology, University of California, Berkeley, Berkeley, CA
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91
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Fan P, Jordan VC. PERK, Beyond an Unfolded Protein Response Sensor in Estrogen-Induced Apoptosis in Endocrine-Resistant Breast Cancer. Mol Cancer Res 2021; 20:193-201. [PMID: 34728551 DOI: 10.1158/1541-7786.mcr-21-0702] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/04/2021] [Accepted: 10/28/2021] [Indexed: 11/16/2022]
Abstract
The discovery of 17β-estradiol (E2)-induced apoptosis has clinical relevance. Mechanistically, E2 over activates nuclear estrogen receptor α that results in stress responses. The unfolded protein response (UPR) is initiated by E2 in the endoplasmic reticulum after hours of treatment in endocrine-resistant breast cancer cells, thereby activating three UPR sensors-PRK-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6 (ATF6) with different functions. Specifically, PERK plays a critical role in induction of apoptosis whereas IRE1α and ATF6 are involved in the endoplasmic reticulum stress-associated degradation (ERAD) of PI3K/Akt/mTOR pathways. In addition to attenuating protein translation, PERK increases the DNA-binding activity of NF-κB and subsequent TNFα expression. In addition, PERK communicates with the mitochondria to regulate oxidative stress at mitochondria-associated endoplasmic reticulum membranes (MAM). Furthermore, PERK is a component enriched in MAMs that interacts with multifunctional MAM-tethering proteins and integrally modulates the exchange of metabolites such as lipids, reactive oxygen species (ROS), and Ca2+ at contact sites. MAMs are also critical sites for the initiation of autophagy to remove defective organelles and misfolded proteins through specific regulatory proteins. Thus, PERK conveys signals from nucleus to these membrane-structured organelles that form an interconnected network to regulate E2-induced apoptosis. Herein, we address the mechanistic progress on how PERK acts as a multifunctional molecule to commit E2 to inducing apoptosis in endocrine-resistant breast cancer.
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Affiliation(s)
- Ping Fan
- Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - V Craig Jordan
- Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
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92
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Kumar S, Sánchez-Álvarez M, Lolo FN, Trionfetti F, Strippoli R, Cordani M. Autophagy and the Lysosomal System in Cancer. Cells 2021; 10:cells10102752. [PMID: 34685734 PMCID: PMC8534995 DOI: 10.3390/cells10102752] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 12/19/2022] Open
Abstract
Autophagy and the lysosomal system, together referred to as the autophagolysosomal system, is a cellular quality control network which maintains cellular health and homeostasis by removing cellular waste including protein aggregates, damaged organelles, and invading pathogens. As such, the autophagolysosomal system has roles in a variety of pathophysiological disorders, including cancer, neurological disorders, immune- and inflammation-related diseases, and metabolic alterations, among others. The autophagolysosomal system is controlled by TFEB, a master transcriptional regulator driving the expression of multiple genes, including autophagoly sosomal components. Importantly, Reactive Oxygen Species (ROS) production and control are key aspects of the physiopathological roles of the autophagolysosomal system, and may hold a key for synergistic therapeutic interventions. In this study, we reviewed our current knowledge on the biology and physiopathology of the autophagolysosomal system, and its potential for therapeutic intervention in cancer.
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Affiliation(s)
- Suresh Kumar
- Autophagy Inflammation and Metabolism Center of Biomedical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
- Correspondence: (S.K.); (R.S.)
| | - Miguel Sánchez-Álvarez
- Mechanoadaptation & Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain; (M.S.-Á.); (F.-N.L.)
| | - Fidel-Nicolás Lolo
- Mechanoadaptation & Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain; (M.S.-Á.); (F.-N.L.)
| | - Flavia Trionfetti
- Department of Molecular Medicine, Sapienza University of Rome, Viale Regina Elena 324, 00161 Rome, Italy;
- National Institute for Infectious Diseases L. Spallanzani, IRCCS, Via Portuense, 292, 00149 Rome, Italy
| | - Raffaele Strippoli
- Mechanoadaptation & Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain; (M.S.-Á.); (F.-N.L.)
- Department of Molecular Medicine, Sapienza University of Rome, Viale Regina Elena 324, 00161 Rome, Italy;
- National Institute for Infectious Diseases L. Spallanzani, IRCCS, Via Portuense, 292, 00149 Rome, Italy
- Correspondence: (S.K.); (R.S.)
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93
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PGRMC1 acts as a size-selective cargo receptor to drive ER-phagic clearance of mutant prohormones. Nat Commun 2021; 12:5991. [PMID: 34645803 PMCID: PMC8514460 DOI: 10.1038/s41467-021-26225-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 09/20/2021] [Indexed: 02/06/2023] Open
Abstract
The reticulon-3 (RTN3)-driven targeting complex promotes clearance of misfolded prohormones from the endoplasmic reticulum (ER) for lysosomal destruction by ER-phagy. Because RTN3 resides in the cytosolic leaflet of the ER bilayer, the mechanism of selecting misfolded prohormones as ER-phagy cargo on the luminal side of the ER membrane remains unknown. Here we identify the ER transmembrane protein PGRMC1 as an RTN3-binding partner. Via its luminal domain, PGRMC1 captures misfolded prohormones, targeting them for RTN3-dependent ER-phagy. PGRMC1 selects cargos that are smaller than the large size of other reported ER-phagy substrates. Cargos for PGRMC1 include mutant proinsulins that block secretion of wildtype proinsulin through dominant-negative interactions within the ER, causing insulin-deficiency. Chemical perturbation of PGRMC1 partially restores WT insulin storage by preventing ER-phagic degradation of WT and mutant proinsulin. Thus, PGRMC1 acts as a size-selective cargo receptor during RTN3-dependent ER-phagy, and is a potential therapeutic target for diabetes.
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94
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Cattelani C, Lesiak D, Liebscher G, Singer II, Stasyk T, Wallnöfer MH, Heberle AM, Corti C, Hess MW, Pfaller K, Kwiatkowski M, Pramstaller PP, Hicks AA, Thedieck K, Müller T, Huber LA, Eca Guimaraes de Araujo M. The SZT2 Interactome Unravels New Functions of the KICSTOR Complex. Cells 2021; 10:2711. [PMID: 34685691 PMCID: PMC8534408 DOI: 10.3390/cells10102711] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/20/2021] [Accepted: 10/05/2021] [Indexed: 12/25/2022] Open
Abstract
Seizure threshold 2 (SZT2) is a component of the KICSTOR complex which, under catabolic conditions, functions as a negative regulator in the amino acid-sensing branch of mTORC1. Mutations in this gene cause a severe neurodevelopmental and epileptic encephalopathy whose main symptoms include epilepsy, intellectual disability, and macrocephaly. As SZT2 remains one of the least characterized regulators of mTORC1, in this work we performed a systematic interactome analysis under catabolic and anabolic conditions. Besides numerous mTORC1 and AMPK signaling components, we identified clusters of proteins related to autophagy, ciliogenesis regulation, neurogenesis, and neurodegenerative processes. Moreover, analysis of SZT2 ablated cells revealed increased mTORC1 signaling activation that could be reversed by Rapamycin or Torin treatments. Strikingly, SZT2 KO cells also exhibited higher levels of autophagic components, independent of the physiological conditions tested. These results are consistent with our interactome data, in which we detected an enriched pool of selective autophagy receptors/regulators. Moreover, preliminary analyses indicated that SZT2 alters ciliogenesis. Overall, the data presented form the basis to comprehensively investigate the physiological functions of SZT2 that could explain major molecular events in the pathophysiology of developmental and epileptic encephalopathy in patients with SZT2 mutations.
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Affiliation(s)
- Cecilia Cattelani
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Dominik Lesiak
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Gudrun Liebscher
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Isabel I. Singer
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Taras Stasyk
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Moritz H. Wallnöfer
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Alexander M. Heberle
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria; (A.M.H.); (M.K.); (K.T.)
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands
| | - Corrado Corti
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Michael W. Hess
- Institute of Histology and Embryology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.W.H.); (K.P.)
| | - Kristian Pfaller
- Institute of Histology and Embryology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.W.H.); (K.P.)
| | - Marcel Kwiatkowski
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria; (A.M.H.); (M.K.); (K.T.)
| | - Peter P. Pramstaller
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Andrew A. Hicks
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Kathrin Thedieck
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria; (A.M.H.); (M.K.); (K.T.)
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands
- Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | - Thomas Müller
- Department of Pediatrics I, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Lukas A. Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
- Austrian Drug Screening Institute, ADSI, 6020 Innsbruck, Austria
| | - Mariana Eca Guimaraes de Araujo
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
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95
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Tian X, Teng J, Chen J. New insights regarding SNARE proteins in autophagosome-lysosome fusion. Autophagy 2021; 17:2680-2688. [PMID: 32924745 PMCID: PMC8525925 DOI: 10.1080/15548627.2020.1823124] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/04/2020] [Accepted: 09/09/2020] [Indexed: 12/26/2022] Open
Abstract
Macroautophagy/autophagy refers to the engulfment of cellular contents selected for lysosomal degradation. The final step in autophagy is the fusion of autophagosome with the lysosome, which is mediated by SNARE proteins. Of the SNAREs, autophagosome-localized Q-SNAREs, such as STX17 and SNAP29, and lysosome-localized R-SNAREs, such as VAMP8 or VAMP7, have been reported to be involved. Recent studies also reveal participation of the R-SNARE, YKT6, in autophagosome-lysosome fusion. These SNAREs, with the help of other regulatory factors, act coordinately to spatiotemporally control the fusion process. Besides regulating autophagosome-lysosome fusion, some SNAREs, such as STX17, also function in other autophagic processes, including autophagosome formation and mitophagy. A better understanding of the functions of SNAREs will shed light on the molecular mechanisms of autophagosome-lysosome fusion as well as on the mechanisms by which autophagy is globally regulated.Abbreviations: ATG: autophagy related; DNM1L: dynamin 1 like; ER: endoplasmic reticulum; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor associated protein like 1; IRGM: immunity related GTPase M; LAMP2: lysosomal associated membrane protein 2; MAP1LC3B/LC3: microtubule associated protein 1 light chain 3 beta; MTOR: mechanistic target of rapamycin kinase; PIK3R4: phosphoinositide-3-kinase regulatory subunit 4; PLEKHM1: pleckstrin homology and RUN domain containing M1; PRKN: PRKN RBR E3 ubiquitin protein ligase; RAB2A: RAB2A, member RAS oncogene family; RAB33B: RAB33B, member RAS oncogene family; RAB7A: RAB7A, member RAS oncogene family; RB1CC1: RB1 inducible coiled-coil 1; RTN3: reticulon 3; RUBCNL: rubicon like autophagy enhancer; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SNAP29: synaptosomal associated protein 29; STX17: syntaxin 17; ULK1: unc-51 like autophagy activating kinase 1; VAMP7: vesicle associated membrane protein 7; VAMP8: vesicle associated membrane protein 8; YKT6: YKT6 v-SNARE homolog.
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Affiliation(s)
- Xiaoyu Tian
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Junlin Teng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
| | - Jianguo Chen
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, China
- Center for Quantitative Biology, Peking University, Beijing, China
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96
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Siva Sankar D, Dengjel J. Protein complexes and neighborhoods driving autophagy. Autophagy 2021; 17:2689-2705. [PMID: 33183148 PMCID: PMC8526019 DOI: 10.1080/15548627.2020.1847461] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/16/2020] [Accepted: 11/02/2020] [Indexed: 01/02/2023] Open
Abstract
Autophagy summarizes evolutionarily conserved, intracellular degradation processes targeting cytoplasmic material for lysosomal degradation. These encompass constitutive processes as well as stress responses, which are often found dysregulated in diseases. Autophagy pathways help in the clearance of damaged organelles, protein aggregates and macromolecules, mediating their recycling and maintaining cellular homeostasis. Protein-protein interaction networks contribute to autophagosome biogenesis, substrate loading, vesicular trafficking and fusion, protein translocations across membranes and degradation in lysosomes. Hypothesis-free proteomic approaches tremendously helped in the functional characterization of protein-protein interactions to uncover molecular mechanisms regulating autophagy. In this review, we elaborate on the importance of understanding protein-protein-interactions of varying affinities and on the strengths of mass spectrometry-based proteomic approaches to study these, generating new mechanistic insights into autophagy regulation. We discuss in detail affinity purification approaches and recent developments in proximity labeling coupled to mass spectrometry, which uncovered molecular principles of autophagy mechanisms.Abbreviations: AMPK: AMP-activated protein kinase; AP-MS: affinity purification-mass spectrometry; APEX2: ascorbate peroxidase-2; ATG: autophagy related; BioID: proximity-dependent biotin identification; ER: endoplasmic reticulum; GFP: green fluorescent protein; iTRAQ: isobaric tag for relative and absolute quantification; MS: mass spectrometry; PCA: protein-fragment complementation assay; PL-MS: proximity labeling-mass spectrometry; PtdIns3P: phosphatidylinositol-3-phosphate; PTM: posttranslational modification; PUP-IT: pupylation-based interaction tagging; RFP: red fluorescent protein; SILAC: stable isotope labeling by amino acids in cell culture; TAP: tandem affinity purification; TMT: tandem mass tag.
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Affiliation(s)
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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97
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Molecular mechanisms of mammalian autophagy. Biochem J 2021; 478:3395-3421. [PMID: 34554214 DOI: 10.1042/bcj20210314] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/19/2021] [Accepted: 07/28/2021] [Indexed: 02/06/2023]
Abstract
The ubiquitin-proteasome pathway (UPP) and autophagy play integral roles in cellular homeostasis. As part of their normal life cycle, most proteins undergo ubiquitination for some form of redistribution, localization and/or functional modulation. However, ubiquitination is also important to the UPP and several autophagic processes. The UPP is initiated after specific lysine residues of short-lived, damaged or misfolded proteins are conjugated to ubiquitin, which targets these proteins to proteasomes. Autophagy is the endosomal/lysosomal-dependent degradation of organelles, invading microbes, zymogen granules and macromolecules such as protein, carbohydrates and lipids. Autophagy can be broadly separated into three distinct subtypes termed microautophagy, chaperone-mediated autophagy and macroautophagy. Although autophagy was once thought of as non-selective bulk degradation, advancements in the field have led to the discovery of several selective forms of autophagy. Here, we focus on the mechanisms of primary and selective mammalian autophagy pathways and highlight the current knowledge gaps in these molecular pathways.
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98
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Respiratory Supercomplexes Promote Mitochondrial Efficiency and Growth in Severely Hypoxic Pancreatic Cancer. Cell Rep 2021; 33:108231. [PMID: 33027658 PMCID: PMC7573785 DOI: 10.1016/j.celrep.2020.108231] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/19/2020] [Accepted: 09/15/2020] [Indexed: 12/14/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is characterized by extensive fibrosis and hypovascularization, resulting in significant intratumoral hypoxia (low oxygen) that contributes to its aggressiveness, therapeutic resistance, and high mortality. Despite oxygen being a fundamental requirement for many cellular and metabolic processes, and the severity of hypoxia in PDAC, the impact of oxygen deprivation on PDAC biology is poorly understood. Investigating how PDAC cells survive in the near absence of oxygen, we find that PDAC cell lines grow robustly in oxygen tensions down to 0.1%, maintaining mitochondrial morphology, membrane potential, and the oxidative metabolic activity required for the synthesis of key metabolites for proliferation. Disrupting electron transfer efficiency by targeting mitochondrial respiratory supercomplex assembly specifically affects hypoxic PDAC proliferation, metabolism, and in vivo tumor growth. Collectively, our results identify a mechanism that enables PDAC cells to thrive in severe, oxygen-limited microenvironments.
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99
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Tu YXI, Sydor AM, Coyaud E, Laurent EMN, Dyer D, Mellouk N, St-Germain J, Vernon RM, Forman-Kay JD, Li T, Hua R, Zhao K, Ridgway ND, Kim PK, Raught B, Brumell JH. Global Proximity Interactome of the Human Macroautophagy Pathway. Autophagy 2021; 18:1174-1186. [PMID: 34524948 PMCID: PMC9196747 DOI: 10.1080/15548627.2021.1965711] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Macroautophagy is a highly conserved eukaryotic cellular pathway involving the engulfment of macromolecules, organelles, and invading microbes by a double-membrane compartment and subsequent lysosomal degradation. The mechanisms that regulate macroautophagy, and the interaction of its components with other cellular pathways, have remained unclear. Here, we performed proximity-dependent biotin identification (BioID) on 39 core human macroautophagy proteins, identifying over 700 unique high confidence proximity interactors with new putative connections between macroautophagic and essential cellular processes. Of note, we identify members of the OSBPL (oxysterol binding protein like) family as Atg8-family protein interactors. We subsequently conducted comprehensive screens of the OSBPL family for LC3B-binding and roles in xenophagy and aggrephagy. OSBPL7 and OSBPL11 emerged as novel lipid transfer proteins required for macroautophagy of selective cargo. Altogether, our proximity interaction map provides a valuable resource for the study of autophagy and highlights the critical role of membrane contact site proteins in the pathway.
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Affiliation(s)
- Yi Xin Iris Tu
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Andrew M Sydor
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Etienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Estelle M N Laurent
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Diana Dyer
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Nora Mellouk
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jonathan St-Germain
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Robert M Vernon
- Molecular Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Julie D Forman-Kay
- Molecular Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Taoyingnan Li
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Rong Hua
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Kexin Zhao
- Departments of Pediatrics and Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Neale D Ridgway
- Departments of Pediatrics and Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Peter K Kim
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - John H Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,SickKids IBD Centre, Hospital for Sick Children, Toronto, Ontario, Canada
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100
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Shiozaki Y, Miyazaki-Anzai S, Keenan AL, Miyazaki M. MEF2D-NR4A1-FAM134B2-mediated reticulophagy contributes to amino acid homeostasis. Autophagy 2021; 18:1049-1061. [PMID: 34517786 DOI: 10.1080/15548627.2021.1968228] [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] [Indexed: 12/15/2022] Open
Abstract
We recently identified FAM134B2, which is an N-terminal truncated reticulophagy receptor highly induced by starvation such as fasting of mice and treatment of mammalian cells with a starvation medium that does not contain amino acids, glucose and growth factors. However, which starvation signal mediates the induction of FAM134B2 is still obscure. In this study, we found that amino acid deficiency (AAD) could mimic the starvation condition to induce FAM134B2 expression. Unexpectedly, EIF2AK4/GCN2-mediated integrated signal response (ISR) and MTOR (mechanistic target of rapamycin kinase) signals, which constitute two major signaling pathways that respond to AAD, did not contribute to AAD-induced FAM134B2 induction. mRNA-seq and siRNA screenings identified two ISR-independent transcription factors, MEF2D (myocyte enhancer factor 2D) and NR4A1 (nuclear receptor subfamily 4 group A member 1), involved in AAD-induced FAM134B2 expression. AAD induces MEF2D, resulting in the induction of NR4A1, which in turn induces FAM134B2-mediated reticulophagy to maintain intracellular amino acid levels. In conclusion, the MEF2D-NR4A1-FAM134B2 cascade is a critical signal in amino acid homeostasis.
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Affiliation(s)
- Yuji Shiozaki
- Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Shinobu Miyazaki-Anzai
- Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Audrey L Keenan
- Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Makoto Miyazaki
- Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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