1
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Popelka H, Klionsky DJ. When an underdog becomes a major player: the role of protein structural disorder in the Atg8 conjugation system. Autophagy 2024:1-8. [PMID: 38808635 DOI: 10.1080/15548627.2024.2357496] [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: 02/18/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024] Open
Abstract
The noncanonical ubiquitin-like conjugation cascade involving the E1 (Atg7), E2 (Atg3, Atg10), and E3 (Atg12-Atg5-Atg16 complex) enzymes is essential for incorporation of Atg8 into the growing phagophore via covalent linkage to PE. This process is an indispensable step in autophagy. Atg8 and E1-E3 enzymes are the first subset from the core autophagy protein machinery structures that were investigated in earlier studies by crystallographic analyses of globular domains. However, research over the past decade shows that many important functions in the conjugation machinery are mediated by intrinsically disordered protein regions (IDPRs) - parts of the protein that do not adopt a stable secondary or tertiary structure, which are inherently dynamic and well suited for protein-membrane interactions but are invisible in protein crystals. Here, we summarize earlier and recent findings on the autophagy conjugation machinery by focusing on the IDPRs. This summary reveals that IDPRs, originally considered dispensable, are in fact major players and a driving force in the function of the autophagy conjugation system. Abbreviation: AD, activation domain of Atg7; AH, amphipathic helix; AIM, Atg8-family interacting motif; CL, catalytic loop (of Atg7); CTD, C-terminal domain; FR, flexible region (of Atg3 or Atg10); GUV, giant unilammelar vesicles; HR, handle region (of Atg3); IDPR, intrinsically disordered protein region; IDPs: intrinsically disordered proteins; LIR, LC3-interacting region; NHD: N-terminal helical domain; NMR, nuclear magnetic resonance; PE, phosphatidylethanolamine; UBL, ubiquitin like.
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Affiliation(s)
- Hana Popelka
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
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2
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Alam JM, Maruyama T, Noshiro D, Kakuta C, Kotani T, Nakatogawa H, Noda NN. Complete set of the Atg8-E1-E2-E3 conjugation machinery forms an interaction web that mediates membrane shaping. Nat Struct Mol Biol 2024; 31:170-178. [PMID: 38057553 DOI: 10.1038/s41594-023-01132-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 09/20/2023] [Indexed: 12/08/2023]
Abstract
Atg8, a ubiquitin-like protein, is conjugated with phosphatidylethanolamine (PE) via Atg7 (E1), Atg3 (E2) and Atg12-Atg5-Atg16 (E3) enzymatic cascade and mediates autophagy. However, its molecular roles in autophagosome formation are still unclear. Here we show that Saccharomyces cerevisiae Atg8-PE and E1-E2-E3 enzymes together construct a stable, mobile membrane scaffold. The complete scaffold formation induces an in-bud in prolate-shaped giant liposomes, transforming their morphology into one reminiscent of isolation membranes before sealing. In addition to their enzymatic roles in Atg8 lipidation, all three proteins contribute nonenzymatically to membrane scaffolding and shaping. Nuclear magnetic resonance analyses revealed that Atg8, E1, E2 and E3 together form an interaction web through multivalent weak interactions, where the intrinsically disordered regions in Atg3 play a central role. These data suggest that all six Atg proteins in the Atg8 conjugation machinery control membrane shaping during autophagosome formation.
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Affiliation(s)
| | | | - Daisuke Noshiro
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Chika Kakuta
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Tetsuya Kotani
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hitoshi Nakatogawa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Nobuo N Noda
- Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan.
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3
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Bueno-Arribas M, Cruz-Cuevas C, Navas MA, Escalante R, Vincent O. Coiled-coil-mediated dimerization of Atg16 is required for binding to the PROPPIN Atg21. Open Biol 2023; 13:230192. [PMID: 37989223 PMCID: PMC10688262 DOI: 10.1098/rsob.230192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/13/2023] [Indexed: 11/23/2023] Open
Abstract
PROPPINs/WIPIs are β-propeller proteins that bind phosphoinositides and contribute to the recruitment of protein complexes involved in membrane remodelling processes such as autophagosome formation and endosomal trafficking. Yeast Atg21 and mammalian WIPI2 interact with Atg16/ATG16L1 to mediate recruitment of the lipidation machinery to the autophagosomal membrane. Here, we used the reverse double two-hybrid method (RD2H) to identify residues in Atg21 and Atg16 critical for protein-protein binding. Although our results are generally consistent with the crystal structure of the Atg21-Atg16 complex reported previously, they also reveal that dimerization of the Atg16 coiled-coil domain is required for Atg21 binding. Furthermore, most of the residues identified in Atg21 are conserved in WIPI2 and we showed that these residues also mediate ATG16L1 binding. Strikingly, these residues occupy the same position in the β-propeller structure as residues in PROPPINs/WIPIs Hsv2 and WIPI4 that mediate Atg2/ATG2A binding, supporting the idea that these proteins use different amino acids at the same position to interact with different autophagic proteins. Finally, our findings demonstrate the effectiveness of the RD2H system to identify critical residues for protein-protein interactions and the utility of this method to generate combinatory mutants with a complete loss of binding capacity.
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Affiliation(s)
- Miranda Bueno-Arribas
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
| | - Celia Cruz-Cuevas
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
| | - María-Angeles Navas
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Ricardo Escalante
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
| | - Olivier Vincent
- Instituto de Investigaciones Biomédicas Sols-Morreale CSIC-UAM, Madrid, 28029, Spain
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4
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Mao B, Yuan W, Wu F, Yan Y, Wang B. Autophagy in hepatic ischemia-reperfusion injury. Cell Death Discov 2023; 9:115. [PMID: 37019879 PMCID: PMC10076300 DOI: 10.1038/s41420-023-01387-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/23/2023] [Accepted: 02/27/2023] [Indexed: 04/07/2023] Open
Abstract
Hepatic ischemia-reperfusion injury (HIRI) is a major complication of liver resection or liver transplantation that can seriously affect patient's prognosis. There is currently no definitive and effective treatment strategy for HIRI. Autophagy is an intracellular self-digestion pathway initiated to remove damaged organelles and proteins, which maintains cell survival, differentiation, and homeostasis. Recent studies have shown that autophagy is involved in the regulation of HIRI. Numerous drugs and treatments can change the outcome of HIRI by controlling the pathways of autophagy. This review mainly discusses the occurrence and development of autophagy, the selection of experimental models for HIRI, and the specific regulatory pathways of autophagy in HIRI. Autophagy has considerable potential in the treatment of HIRI.
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Affiliation(s)
- Benliang Mao
- College of Clinical Medicine, Guizhou Medical University, Guiyang, China
| | - Wei Yuan
- Department of General Surgery, Guangzhou Red Cross Hospital affiliated to Jinan University, Guangzhou, China
| | - Fan Wu
- Department of General Surgery, Guangzhou Red Cross Hospital affiliated to Jinan University, Guangzhou, China
| | - Yong Yan
- Department of General Surgery, Guangzhou Red Cross Hospital affiliated to Jinan University, Guangzhou, China
| | - Bailin Wang
- College of Clinical Medicine, Guizhou Medical University, Guiyang, China.
- Department of General Surgery, Guangzhou Red Cross Hospital affiliated to Jinan University, Guangzhou, China.
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5
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Iriondo MN, Etxaniz A, Varela YR, Ballesteros U, Lázaro M, Valle M, Fracchiolla D, Martens S, Montes LR, Goñi FM, Alonso A. Effect of ATG12-ATG5-ATG16L1 autophagy E3-like complex on the ability of LC3/GABARAP proteins to induce vesicle tethering and fusion. Cell Mol Life Sci 2023; 80:56. [PMID: 36729310 PMCID: PMC9894987 DOI: 10.1007/s00018-023-04704-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 02/03/2023]
Abstract
In macroautophagy, the autophagosome (AP) engulfs portions of cytoplasm to allow their lysosomal degradation. AP formation in humans requires the concerted action of the ATG12 and LC3/GABARAP conjugation systems. The ATG12-ATG5-ATG16L1 or E3-like complex (E3 for short) acts as a ubiquitin-like E3 enzyme, promoting LC3/GABARAP proteins anchoring to the AP membrane. Their role in the AP expansion process is still unclear, in part because there are no studies comparing six LC3/GABARAP family member roles under the same conditions, and also because the full human E3 was only recently available. In the present study, the lipidation of six members of the LC3/GABARAP family has been reconstituted in the presence and absence of E3, and the mechanisms by which E3 and LC3/GABARAP proteins participate in vesicle tethering and fusion have been investigated. In the absence of E3, GABARAP and GABARAPL1 showed the highest activities. Differences found within LC3/GABARAP proteins suggest the existence of a lipidation threshold, lower for the GABARAP subfamily, as a requisite for tethering and inter-vesicular lipid mixing. E3 increases and speeds up lipidation and LC3/GABARAP-promoted tethering. However, E3 hampers LC3/GABARAP capacity to induce inter-vesicular lipid mixing or subsequent fusion, presumably through the formation of a rigid scaffold on the vesicle surface. Our results suggest a model of AP expansion in which the growing regions would be areas where the LC3/GABARAP proteins involved should be susceptible to lipidation in the absence of E3, or else a regulatory mechanism would allow vesicle incorporation and phagophore growth when E3 is present.
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Affiliation(s)
- Marina N Iriondo
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
| | - Asier Etxaniz
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
| | - Yaiza R Varela
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
| | - Uxue Ballesteros
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
| | - Melisa Lázaro
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160, Derio, Bizkaia, Spain
| | - Mikel Valle
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160, Derio, Bizkaia, Spain
| | - Dorotea Fracchiolla
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Sascha Martens
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - L Ruth Montes
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
| | - Félix M Goñi
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain
| | - Alicia Alonso
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940, Leioa, Spain.
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940, Leioa, Spain.
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6
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Zhang S, Yazaki E, Sakamoto H, Yamamoto H, Mizushima N. Evolutionary diversification of the autophagy-related ubiquitin-like conjugation systems. Autophagy 2022; 18:2969-2984. [PMID: 35427200 PMCID: PMC9673942 DOI: 10.1080/15548627.2022.2059168] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Two autophagy-related (ATG) ubiquitin-like conjugation systems, the ATG12 and ATG8 systems, play important roles in macroautophagy. While multiple duplications and losses of the ATG conjugation system proteins are found in different lineages, the extent to which the underlying systems diversified across eukaryotes is not fully understood. Here, in order to understand the evolution of the ATG conjugation systems, we constructed a transcriptome database consisting of 94 eukaryotic species covering major eukaryotic clades and systematically identified ATG conjugation system components. Both ATG10 and the C-terminal glycine of ATG12 are essential for the canonical ubiquitin-like conjugation of ATG12 and ATG5. However, loss of ATG10 or the C-terminal glycine of ATG12 occurred at least 16 times in a wide range of lineages, suggesting that possible covalent-to-non-covalent transition is not limited to the species that we previously reported such as Alveolata and some yeast species. Some species have only the ATG8 system (with conjugation enzymes) or only ATG8 (without conjugation enzymes). More than 10 species have ATG8 homologs without the conserved C-terminal glycine, and Tetrahymena has an ATG8 homolog with a predicted transmembrane domain, which may be able to anchor to the membrane independent of the ATG conjugation systems. We discuss the possibility that the ancestor of the ATG12 and ATG8 systems is more similar to ATG8. Overall, our study offers a whole picture of the evolution and diversity of the ATG conjugation systems among eukaryotes, and provides evidence that functional diversifications of the systems are more common than previously thought.Abbreviations: APEAR: ATG8-PE association region; ATG: autophagy-related; LIR: LC3-interacting region; NEDD8: neural precursor cell expressed, developmentally down-regulated gene 8; PE: phosphatidylethanolamine; SAMP: small archaeal modifier protein; SAR: Stramenopiles, Alveolata, and Rhizaria; SMC: structural maintenance of chromosomes; SUMO: small ubiquitin like modifier; TACK: Thaumarchaeota, Aigarchaeota, Crenarchaeota, and Korarchaeota; UBA: ubiquitin like modifier activating enzyme; UFM: ubiquitin fold modifier; URM: ubiquitin related modifier.
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Affiliation(s)
- Sidi Zhang
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Euki Yazaki
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN, Saitama, Japan
| | - Hirokazu Sakamoto
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,Department of Infection and Host Defense, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Hayashi Yamamoto
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,CONTACT Noboru Mizushima Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo113-0033, Japan
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7
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Huang X, Yao J, Liu L, Luo Y, Yang A. Atg8-PE protein-based in vitro biochemical approaches to autophagy studies. Autophagy 2022; 18:2020-2035. [PMID: 35072587 PMCID: PMC9397461 DOI: 10.1080/15548627.2022.2025572] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Macroautophagy/autophagy is an evolutionarily conserved intracellular degradation pathway that maintains cellular homeostasis. Over the past two decades, a series of scientific breakthroughs have helped explain autophagy-related molecular mechanisms and physiological functions. This tremendous progress continues to depend largely on powerful research methods, specifically, various autophagy marker Atg8-PE protein-based methods for studying membrane dynamics and monitoring autophagic activity. Recently, several biochemical approaches have been successfully developed to produce the lipidated protein Atg8-PE or its mimics in vitro, including enzyme-mediated reconstitution systems, chemically defined reconstitution systems, cell-free lipidation systems and protein chemical synthesis. These approaches have contributed important insights into the mechanisms underlying Atg8-mediated membrane dynamics and protein-protein interactions, creating a new perspective in autophagy studies. In this review, we comprehensively summarize Atg8-PE protein-based in vitro biochemical approaches and recent advances to facilitate a better understanding of autophagy mechanisms. In addition, we highlight the advantages and disadvantages of various Atg8-PE protein-based approaches to provide general guidance for their use in studying autophagy.Abbreviations: ATG: autophagy related; ATP: adenosine triphosphate; COPII: coat protein complex II; DGS-NTA: 1,2-dioleoyl-sn-glycero-3-[(N-(5-amino-1-carboxypentyl)iminodiacetic acid)succinyl] (nickel salt); DPPE: 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine; DSPE: 1,2-distearoyl-sn-glycero-3-phosphoethanolamine; E. coli: Escherichia coli; EPL: expressed protein ligation; ERGIC: ER-Golgi intermediate compartment; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor associated protein like 1; GABARAPL2: GABA type A receptor associated protein like 2; GFP: green fluorescent protein; GUVs: giant unilamellar vesicles; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MBP: maltose binding protein; MEFs: mouse embryonic fibroblasts; MESNa: 2-mercaptoethanesulfonic acid sodium salt; NCL: native chemical ligation; NTA: nitrilotriacetic acid; PE: phosphatidylethanolamine; PS: phosphatidylserine; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; SPPS: solid-phase peptide synthesis; TEV: tobacco etch virus; WT: wild-type.
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Affiliation(s)
- Xue Huang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Jia Yao
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Lu Liu
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Yu Luo
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing, China,CONTACT Aimin Yang School of Life Sciences, Chongqing University, Chongqing, China
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8
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Zhang Z, Sun Y, Xue J, Jin D, Li X, Zhao D, Lian F, Qi W, Tong X. The critical role of dysregulated autophagy in the progression of diabetic kidney disease. Front Pharmacol 2022; 13:977410. [PMID: 36091814 PMCID: PMC9453227 DOI: 10.3389/fphar.2022.977410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/04/2022] [Indexed: 11/30/2022] Open
Abstract
Diabetic kidney disease (DKD) is one of the major public health problems in society today. It is a renal complication caused by diabetes mellitus with predominantly microangiopathy and is a major cause of end-stage renal disease (ESRD). Autophagy is a metabolic pathway for the intracellular degradation of cytoplasmic products and damaged organelles and plays a vital role in maintaining homeostasis and function of the renal cells. The dysregulation of autophagy in the hyperglycaemic state of diabetes mellitus can lead to the progression of DKD, and the activation or restoration of autophagy through drugs is beneficial to the recovery of renal function. This review summarizes the physiological process of autophagy, illustrates the close link between DKD and autophagy, and discusses the effects of drugs on autophagy and the signaling pathways involved from the perspective of podocytes, renal tubular epithelial cells, and mesangial cells, in the hope that this will be useful for clinical treatment.
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Affiliation(s)
- Ziwei Zhang
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Yuting Sun
- Department of Endocrinology, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jiaojiao Xue
- College of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - De Jin
- Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou, China
| | - Xiangyan Li
- Northeast Asia Research Institute of Traditional Chinese Medicine, Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of Biomacromolecules of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Daqing Zhao
- Northeast Asia Research Institute of Traditional Chinese Medicine, Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of Biomacromolecules of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Fengmei Lian
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Fengmei Lian, ; Wenxiu Qi, ; Xiaolin Tong,
| | - Wenxiu Qi
- Northeast Asia Research Institute of Traditional Chinese Medicine, Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of Biomacromolecules of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
- *Correspondence: Fengmei Lian, ; Wenxiu Qi, ; Xiaolin Tong,
| | - Xiaolin Tong
- Institute of Metabolic Diseases, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Fengmei Lian, ; Wenxiu Qi, ; Xiaolin Tong,
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9
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Characterization of Protein-Membrane Interactions in Yeast Autophagy. Cells 2022; 11:cells11121876. [PMID: 35741004 PMCID: PMC9221364 DOI: 10.3390/cells11121876] [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: 05/10/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 02/06/2023] Open
Abstract
Cells rely on autophagy to degrade cytosolic material and maintain homeostasis. During autophagy, content to be degraded is encapsulated in double membrane vesicles, termed autophagosomes, which fuse with the yeast vacuole for degradation. This conserved cellular process requires the dynamic rearrangement of membranes. As such, the process of autophagy requires many soluble proteins that bind to membranes to restructure, tether, or facilitate lipid transfer between membranes. Here, we review the methods that have been used to investigate membrane binding by the core autophagy machinery and additional accessory proteins involved in autophagy in yeast. We also review the key experiments demonstrating how each autophagy protein was shown to interact with membranes.
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10
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Theater in the Self-Cleaning Cell: Intrinsically Disordered Proteins or Protein Regions Acting with Membranes in Autophagy. MEMBRANES 2022; 12:membranes12050457. [PMID: 35629783 PMCID: PMC9143426 DOI: 10.3390/membranes12050457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 12/30/2022]
Abstract
Intrinsically disordered proteins and protein regions (IDPs/IDPRs) are mainly involved in signaling pathways, where fast regulation, temporal interactions, promiscuous interactions, and assemblies of structurally diverse components including membranes are essential. The autophagy pathway builds, de novo, a membrane organelle, the autophagosome, using carefully orchestrated interactions between proteins and lipid bilayers. Here, we discuss molecular mechanisms related to the protein disorder-based interactions of the autophagy machinery with membranes. We describe not only membrane binding phenomenon, but also examples of membrane remodeling processes including membrane tethering, bending, curvature sensing, and/or fragmentation of membrane organelles such as the endoplasmic reticulum, which is an important membrane source as well as cargo for autophagy. Summary of the current state of knowledge presented here will hopefully inspire new studies. A profound understanding of the autophagic protein–membrane interface is essential for advancements in therapeutic interventions against major human diseases, in which autophagy is involved including neurodegeneration, cancer as well as cardiovascular, metabolic, infectious, musculoskeletal, and other disorders.
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11
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Xu X, Yu Z, Han B, Li S, Sun Y, Du Y, Wang Z, Gao D, Zhang Z. Luteolin alleviates inorganic mercury-induced kidney injury via activation of the AMPK/mTOR autophagy pathway. J Inorg Biochem 2021; 224:111583. [PMID: 34428638 DOI: 10.1016/j.jinorgbio.2021.111583] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/14/2021] [Accepted: 08/15/2021] [Indexed: 12/11/2022]
Abstract
Inorganic mercury is a ubiquitous toxic pollutant in the environment. Exposure to inorganic mercury can cause various poisonous effects, including kidney injury. However, no safe and effective treatment for kidney injury caused by inorganic mercury has been found and used. Luteolin (Lut) possesses various beneficial bioactivities. Here, our research aims to investigate the protective effect of Lut on renal injury induced by mercury chloride (HgCl2) and identify the underlying autophagy regulation mechanism. Twenty-eight 6-8 weeks old Wistar rats were randomly assigned to four groups: control, HgCl2, HgCl2 + Lut, and Lut. We performed the determination of oxidative stress and renal function indicators, histopathological analysis, the terminal deoxynucleotidyl transferase-mediated deoxyuracil nucleoside triphosphate nick-end labeling assay to detect apoptosis, western blot detection of autophagy-related protein levels, and atomic absorption method to detect mercury content. Our results showed that Lut ameliorated oxidative stress, apoptosis and restored the autophagy and renal function caused by HgCl2 in rats. Concretely, the level of nuclear factor E2-related factor, renal adenosine monophosphate-activated protein kinase (AMPK) expression, and autophagy regulation-related proteins levels were down-regulated, and the mammalian target of rapamycin (mTOR) expression was up-regulated by HgCl2 treatment. However, Lut treatment reversed the above changes. Notably, Lut reduced the accumulation of HgCl2 in the kidneys and promoted the excretion of HgCl2 through urine. Collectively, our results demonstrate that Lut can attenuate inorganic mercury-induced renal injury via activating the AMPK/mTOR autophagy pathway. Therefore, Lut may be a potential biological medicine to protect against renal damage induced by HgCl2.
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Affiliation(s)
- Xinyue Xu
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China
| | - Zhongxian Yu
- Pharmacy Department, The Affiliated Hospital to Changchun University of Chinese Medicine, 1478 Gongnong Road, Hongqi Street, Chaoyang District, Changchun City, Jilin Province 130021, China
| | - Biqi Han
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China
| | - Siyu Li
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China
| | - Yingshuo Sun
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China
| | - Yu Du
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China
| | - Ziwei Wang
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China
| | - Di Gao
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China
| | - Zhigang Zhang
- College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin 150030, China; Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, 600 Changjiang Road, Harbin 150030, China.
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Popelka H, Klionsky DJ. Multiple structural rearrangements mediated by high-plasticity regions in Atg3 are key for efficient conjugation of Atg8 to PE during autophagy. Autophagy 2021; 17:1805-1808. [PMID: 34338142 DOI: 10.1080/15548627.2021.1954457] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The Atg3 protein is highly homologous from yeast to human. Atg3 functions as an E2-like enzyme promoting conjugation of Atg8-family proteins to phosphatidylethanolamine (PE), a lipid molecule embedded in the growing phagophore membrane during stress-induced autophagy. Over the last decade, Atg3 became one of the most explored autophagy proteins, resulting in observations that provided specific insights into the structural mechanisms of its function. In this article, we describe a recent study by Ye et al. that reveals, using the human ATG3, how the membrane binding capability of the enzyme is tightly linked to its conjugation activity. We summarize the current knowledge on important mechanisms that involve protein-protein or protein-membrane interactions of Atg3 and that ultimately lead to efficient Atg8-PE conjugation.Abbreviations: AH: amphipathic helix; FR: flexible region; HR: handle region; NMR: nuclear magnetic resonance.
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Affiliation(s)
- Hana Popelka
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
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