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Abstract
Autophagy is a self-digestive process that is conserved in eukaryotic cells and responsible for maintaining cellular homeostasis through proteolysis. By this process, cells break down their own components in lysosomes. Autophagy can be classified into three categories: macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Macroautophagy involves membrane elongation and microautophagy involves membrane internalization, and both pathways undergo selective or non-selective processes that transport cytoplasmic components into lysosomes to be degraded. CMA, however, involves selective incorporation of cytosolic materials into lysosomes without membrane deformation. All three categories of autophagy have attracted much attention due to their involvement in various biological phenomena and their relevance to human diseases, such as neurodegenerative diseases and cancer. Clarification of the molecular mechanisms behind these processes is key to understanding autophagy and recent studies have made major progress in this regard, especially for the mechanisms of initiation and membrane elongation in macroautophagy and substrate recognition in microautophagy and CMA. Furthermore, it is becoming evident that the three categories of autophagy are related to each other despite their implementation by different sets of proteins and the involvement of completely different membrane dynamics. In this review, recent progress in macroautophagy, microautophagy, and CMA are summarized.
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Affiliation(s)
- Hayashi Yamamoto
- Department of Molecular Oncology, Institute for Advanced Medical Sciences, Nippon Medical School
| | - Takahide Matsui
- Department of Molecular Oncology, Institute for Advanced Medical Sciences, Nippon Medical School
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2
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Yagyu M, Yoshimoto K. New insights into plant autophagy: molecular mechanisms and roles in development and stress responses. J Exp Bot 2024; 75:1234-1251. [PMID: 37978884 DOI: 10.1093/jxb/erad459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 11/17/2023] [Indexed: 11/19/2023]
Abstract
Autophagy is an evolutionarily conserved eukaryotic intracellular degradation process. Although the molecular mechanisms of plant autophagy share similarities with those in yeast and mammals, certain unique mechanisms have been identified. Recent studies have highlighted the importance of autophagy during vegetative growth stages as well as in plant-specific developmental processes, such as seed development, germination, flowering, and somatic reprogramming. Autophagy enables plants to adapt to and manage severe environmental conditions, such as nutrient starvation, high-intensity light stress, and heat stress, leading to intracellular remodeling and physiological changes in response to stress. In the past, plant autophagy research lagged behind similar studies in yeast and mammals; however, recent advances have greatly expanded our understanding of plant-specific autophagy mechanisms and functions. This review summarizes current knowledge and latest research findings on the mechanisms and roles of plant autophagy with the objective of improving our understanding of this vital process in plants.
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Affiliation(s)
- Mako Yagyu
- Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
- Life Sciences Program, Graduate School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Kohki Yoshimoto
- Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
- Life Sciences Program, Graduate School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
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3
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Kim H, Budin I. Intracellular sphingolipid sorting drives membrane phase separation in the yeast vacuole. J Biol Chem 2024; 300:105496. [PMID: 38013088 PMCID: PMC10776997 DOI: 10.1016/j.jbc.2023.105496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 11/08/2023] [Accepted: 11/19/2023] [Indexed: 11/29/2023] Open
Abstract
The yeast vacuole membrane can phase separate into ordered and disordered domains, a phenomenon that is required for micro-lipophagy under nutrient limitation. Despite its importance as a biophysical model and physiological significance, it is not yet resolved if specific lipidome changes drive vacuole phase separation. Here we report that the metabolism of sphingolipids (SLs) and their sorting into the vacuole membrane can control this process. We first developed a vacuole isolation method to identify lipidome changes during the onset of phase separation in early stationary stage cells. We found that early stationary stage vacuoles are defined by an increased abundance of putative raft components, including 40% higher ergosterol content and a nearly 3-fold enrichment in complex SLs (CSLs). These changes were not found in the corresponding whole cell lipidomes, indicating that lipid sorting is associated with domain formation. Several facets of SL composition-headgroup stoichiometry, longer chain lengths, and increased hydroxylations-were also markers of phase-separated vacuole lipidomes. To test SL function in vacuole phase separation, we carried out a systematic genetic dissection of their biosynthetic pathway. The abundance of CSLs controlled the extent of domain formation and associated micro-lipophagy processes, while their headgroup composition altered domain morphology. These results suggest that lipid trafficking can drive membrane phase separation in vivo and identify SLs as key mediators of this process in yeast.
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Affiliation(s)
- Hyesoo Kim
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Itay Budin
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA.
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4
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Sakai Y, Oku M. ATG and ESCRT control multiple modes of microautophagy. FEBS Lett 2024; 598:48-58. [PMID: 37857501 DOI: 10.1002/1873-3468.14760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 10/21/2023]
Abstract
The discovery of microautophagy, the direct engulfment of cytoplasmic material by the lysosome, dates back to 1966 in a morphological study of mammalian cells by Christian de Duve. Since then, studies on microautophagy have shifted toward the elucidation of the physiological significance of the process. However, in contrast to macroautophagy, studies on the molecular mechanisms of microautophagy have been limited. Only recent studies revealed that ATG proteins involved in macroautophagy are also operative in several types of microautophagy and that ESCRT proteins, responsible for the multivesicular body pathway, play a central role in most microautophagy processes. In this review, we summarize our current knowledge on the function of ATG and ESCRT proteins in microautophagy.
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Affiliation(s)
- Yasuyoshi Sakai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Japan
| | - Masahide Oku
- Department of Bioscience and Biotechnology, Faculty of Bioenvironmental Sciences, Kyoto University of Advanced Science, Kameoka, Japan
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5
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Krause GJ, Kirchner P, Stiller B, Morozova K, Diaz A, Chen KH, Krogan NJ, Agullo-Pascual E, Clement CC, Lindenau K, Swaney DL, Dilipkumar S, Bravo-Cordero JJ, Santambrogio L, Cuervo AM. Molecular determinants of the crosstalk between endosomal microautophagy and chaperone-mediated autophagy. Cell Rep 2023; 42:113529. [PMID: 38060380 PMCID: PMC10807933 DOI: 10.1016/j.celrep.2023.113529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 09/12/2023] [Accepted: 11/17/2023] [Indexed: 12/30/2023] Open
Abstract
Chaperone-mediated autophagy (CMA) and endosomal microautophagy (eMI) are pathways for selective degradation of cytosolic proteins in lysosomes and late endosomes, respectively. These autophagic processes share as a first step the recognition of the same five-amino-acid motif in substrate proteins by the Hsc70 chaperone, raising the possibility of coordinated activity of both pathways. In this work, we show the existence of a compensatory relationship between CMA and eMI and identify a role for the chaperone protein Bag6 in triage and internalization of eMI substrates into late endosomes. Association and dynamics of Bag6 at the late endosome membrane change during starvation, a stressor that, contrary to other autophagic pathways, causes a decline in eMI activity. Collectively, these results show a coordinated function of eMI with CMA, identify the interchangeable subproteome degraded by these pathways, and start to elucidate the molecular mechanisms that facilitate the switch between them.
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Affiliation(s)
- Gregory J Krause
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Philipp Kirchner
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Barbara Stiller
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kateryna Morozova
- Department of Radiation Oncology, Weill Cornell School of Medicine, New York, NY 10021, USA
| | - Antonio Diaz
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kuei-Ho Chen
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; The J. David Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA 94158, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; The J. David Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA 94158, USA
| | | | - Cristina C Clement
- Department of Radiation Oncology, Weill Cornell School of Medicine, New York, NY 10021, USA
| | - Kristen Lindenau
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Danielle L Swaney
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; The J. David Gladstone Institutes, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA 94158, USA
| | - Shilpa Dilipkumar
- Microscopy CoRE, Dean's CoREs, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jose Javier Bravo-Cordero
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Laura Santambrogio
- Department of Radiation Oncology, Weill Cornell School of Medicine, New York, NY 10021, USA.
| | - Ana Maria Cuervo
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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6
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Kuchitsu Y, Taguchi T. Lysosomal microautophagy: an emerging dimension in mammalian autophagy. Trends Cell Biol 2023:S0962-8924(23)00238-6. [PMID: 38104013 DOI: 10.1016/j.tcb.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 12/19/2023]
Abstract
Autophagy is a self-catabolic process through which cellular components are delivered to lysosomes for degradation. There are three types of autophagy, i.e., macroautophagy, chaperone-mediated autophagy (CMA), and microautophagy. In macroautophagy, a portion of the cytoplasm is wrapped by the autophagosome, which then fuses with lysosomes and delivers the engulfed cytoplasm for degradation. In CMA, the translocation of cytosolic substrates to the lysosomal lumen is directly across the limiting membrane of lysosomes. In microautophagy, lytic organelles, including endosomes or lysosomes, take up a portion of the cytoplasm directly. Although macroautophagy has been investigated extensively, microautophagy has received much less attention. Nonetheless, it has become evident that microautophagy plays a variety of cellular roles from yeast to mammals. Here we review the very recent updates of microautophagy. In particular, we focus on the feature of the degradative substrates and the molecular machinery that mediates microautophagy.
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Affiliation(s)
- Yoshihiko Kuchitsu
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
| | - Tomohiko Taguchi
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
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7
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Ogura M, Kaminishi T, Shima T, Torigata M, Bekku N, Tabata K, Minami S, Nishino K, Nezu A, Hamasaki M, Kosako H, Yoshimori T, Nakamura S. Microautophagy regulated by STK38 and GABARAPs is essential to repair lysosomes and prevent aging. EMBO Rep 2023; 24:e57300. [PMID: 37987447 DOI: 10.15252/embr.202357300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 11/22/2023] Open
Abstract
Lysosomes are degradative organelles and signaling hubs that maintain cell and tissue homeostasis, and lysosomal dysfunction is implicated in aging and reduced longevity. Lysosomes are frequently damaged, but their repair mechanisms remain unclear. Here, we demonstrate that damaged lysosomal membranes are repaired by microautophagy (a process termed "microlysophagy") and identify key regulators of the first and last steps. We reveal the AGC kinase STK38 as a novel microlysophagy regulator. Through phosphorylation of the scaffold protein DOK1, STK38 is specifically required for the lysosomal recruitment of the AAA+ ATPase VPS4, which terminates microlysophagy by promoting the disassembly of ESCRT components. By contrast, microlysophagy initiation involves non-canonical lipidation of ATG8s, especially the GABARAP subfamily, which is required for ESCRT assembly through interaction with ALIX. Depletion of STK38 and GABARAPs accelerates DNA damage-induced cellular senescence in human cells and curtails lifespan in C. elegans, respectively. Thus, microlysophagy is regulated by STK38 and GABARAPs and could be essential for maintaining lysosomal integrity and preventing aging.
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Affiliation(s)
- Monami Ogura
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Tatsuya Kaminishi
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Takayuki Shima
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Miku Torigata
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Nao Bekku
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Keisuke Tabata
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Satoshi Minami
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kohei Nishino
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Akiko Nezu
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Maho Hamasaki
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Hidetaka Kosako
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Tamotsu Yoshimori
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Osaka, Japan
| | - Shuhei Nakamura
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
- Institute for Advanced Co-Creation Studies, Osaka University, Osaka, Japan
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8
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Taguchi T. Membrane traffic governs the STING inflammatory signalling. J Biochem 2023; 174:483-490. [PMID: 37562849 DOI: 10.1093/jb/mvad064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/12/2023] Open
Abstract
The cGAS-STING innate immune pathway has recently emerged as a critical driver of inflammation in a variety of settings, such as virus infection, cellular stress and tissue damage. The pathway detects microbial and host-derived double-stranded DNA (dsDNA) in the cytosol, and triggers the production of the type I interferons through the activation of IRF3. The detailed mechanistic and biochemical understanding of the pathway has enabled the development of pharmacological agents for the treatment of chronic inflammation and cancer. STING is an endoplasmic reticulum (ER)-localized transmembrane protein. Upon emergence of cytosolic dsDNA, STING exits the ER and migrates sequentially to the Golgi, recycling endosomes and lysosomes. Importantly, the intracellular translocation of STING is essential for the activation and inactivation of the STING signalling. In this review, I summarize the recent insights into the regulators of the membrane traffic of STING and STING-associated autoinflammatory diseases.
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Affiliation(s)
- Tomohiko Taguchi
- Laboratory of Organelle Pathophysiology, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
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9
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Xu Y, Qian C, Wang Q, Song L, He Z, Liu W, Wan W. Deacetylation of ATG7 drives the induction of macroautophagy and LC3-associated microautophagy. Autophagy 2023:1-13. [PMID: 37999993 DOI: 10.1080/15548627.2023.2287932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/20/2023] [Indexed: 11/26/2023] Open
Abstract
LC3 lipidation plays an important role in the regulation of macroautophagy and LC3-associated microautophagy. The E1-like enzyme ATG7 is one of the core components that are directly involved in LC3 lipidation reaction. Here, we provide evidence showing that acetylation of ATG7 tightly controls its enzyme activity to regulate the induction of macroautophagy and LC3-associated microautophagy. Mechanistically, acetylation of ATG7 disrupts its interaction with the E2-like enzyme ATG3, leading to an inhibition of LC3 lipidation in vitro and in vivo. Functionally, in response to various different stimuli, cellular ATG7 undergoes deacetylation to induce macroautophagy and LC3-associated microautophagy, which are necessary for cells to eliminate cytoplasmic DNA and degrade lysosome membrane proteins, respectively. Taken together, these findings reveal that ATG7 acetylation acts as a critical rheostat in controlling LC3 lipidation and related cellular processes.Abbreviations: AMPK: AMP-activated protein kinase; ATG: autophagy-related; cGAMP: cyclic GMP-AMP; CGAS: cyclic GMP-AMP synthase; CREBBP/CBP: CREB binding protein; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; EP300/p300: E1A binding protein p300; IFNB1: interferon beta 1; ISD: interferon stimulatory DNA; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MCOLN1/TRPML1: mucolipin TRP cation channel 1; MEF: mouse embryonic fibroblast; MTOR: mechanistic target of rapamycin kinase; NAM: nicotinamide; PE: phosphatidylethanolamine; PTM: post-translational modification; RB1CC1/FIP200: RB1 inducible coiled-coil 1; SIRT: sirtuin; SQSTM1/p62: sequestosome 1; STING1: stimulator of interferon response cGAMP interactor 1; TSA: trichostatin A; ULK1: unc-51 like autophagy activating kinase 1; WIPI2: WD repeat domain, phosphoinositide interacting 2; WT: wild-type.
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Affiliation(s)
- Yinfeng Xu
- Laboratory of Basic Biology, Hunan First Normal University, Changsha, Hunan, China
| | - Chuying Qian
- Department of Biochemistry, and Department of Thoracic Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Qian Wang
- Department of Biochemistry, and Department of Thoracic Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Lijiang Song
- Department of Biochemistry, and Department of Thoracic Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Zhengfu He
- Department of Biochemistry, and Department of Thoracic Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Wei Liu
- Department of Metabolic Medicine, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Wei Wan
- Department of Biochemistry, and Department of Thoracic Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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10
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Watanabe Y, Taguchi K, Tanaka M. Roles of Stress Response in Autophagy Processes and Aging-Related Diseases. Int J Mol Sci 2023; 24:13804. [PMID: 37762105 PMCID: PMC10531041 DOI: 10.3390/ijms241813804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/02/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
The heat shock factor 1 (HSF1)-mediated stress response pathway and autophagy processes play important roles in the maintenance of proteostasis. Autophagy processes are subdivided into three subtypes: macroautophagy, chaperone-mediated autophagy (CMA), and microautophagy. Recently, molecular chaperones and co-factors were shown to be involved in the selective degradation of substrates by these three autophagy processes. This evidence suggests that autophagy processes are regulated in a coordinated manner by the HSF1-mediated stress response pathway. Recently, various studies have demonstrated that proteostasis pathways including HSF1 and autophagy are implicated in longevity. Furthermore, they serve as therapeutic targets for aging-related diseases such as cancer and neurodegenerative diseases. In the future, these studies will underpin the development of therapies against various diseases.
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Affiliation(s)
- Yoshihisa Watanabe
- Department of Basic Geriatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto 602-8566, Japan
| | - Katsutoshi Taguchi
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 601-0841, Japan; (K.T.); (M.T.)
| | - Masaki Tanaka
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 601-0841, Japan; (K.T.); (M.T.)
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11
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Marquardt L, Montino M, Mühe Y, Schlotterhose P, Thumm M. Topology and Function of the S. cerevisiae Autophagy Protein Atg15. Cells 2023; 12:2056. [PMID: 37626866 PMCID: PMC10453639 DOI: 10.3390/cells12162056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
The putative phospholipase Atg15 is required for the intravacuolar lysis of autophagic bodies and MVB vesicles. Intracellular membrane lysis is a highly sophisticated mechanism that is not fully understood. The amino-terminal transmembrane domain of Atg15 contains the sorting signal for entry into the MVB pathway. By replacing this domain, we generated chimeras located in the cytosol, the vacuole membrane, and the lumen. The variants at the vacuole membrane and in the lumen were highly active. Together with the absence of Atg15 from the phagophore and autophagic bodies, this suggests that, within the vacuole, Atg15 can lyse vesicles where it is not embedded. In-depth topological analyses showed that Atg15 is a single membrane-spanning protein with the amino-terminus in the cytosol and the rest, including the active site motif, in the ER lumen. Remarkably, only membrane-embedded Atg15 variants affected growth when overexpressed. The growth defects depended on its active site serine 332, showing that it was linked to the enzymatic activity of Atg15. Interestingly, the growth defects were independent of vacuolar proteinase A and vacuolar acidification.
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Affiliation(s)
| | | | | | | | - Michael Thumm
- Institute of Cellular Biochemistry, University Medicine, Humboldtallee 23, D-37073 Goettingen, Germany
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12
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Goto-Yamada S, Oikawa K, Hayashi Y, Mano S, Yamada K, Nishimura M. Pexophagy in plants: a mechanism to remit cells from oxidative damage caused under high-intensity light. Autophagy 2023; 19:1611-1613. [PMID: 36760098 PMCID: PMC10240969 DOI: 10.1080/15548627.2023.2175570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/11/2023] Open
Abstract
Light is essential for plant growth, but excessive light energy produces reactive oxygen species (ROS), which can seriously damage cells. Mutants defective in ATG (autophagy related) genes show light intensity-dependent leaf damage and ROS accumulation. We found that autophagy is one of the crucial systems in protecting plants from ROS-induced damage by removing oxidative peroxisomes. Damaged peroxisomes are targeted by the PtdIns3P marker and specifically engulfed by phagophores labeled by ATG18a-GFP. Under high-intensity light, huge peroxisome aggregates are induced and captured by vacuolar membranes. Research provides a deeper understanding of plant stress response to light irradiation.
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Affiliation(s)
- Shino Goto-Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Kazusato Oikawa
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, Japan
| | - Yasuko Hayashi
- Department of Science, Faculty of Science, Niigata University, Niigata, Japan
| | - Shoji Mano
- Laboratory of Organelle Regulation, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Kenji Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, Japan
- Faculty of Science and Engineering, Konan University, Kobe, Japan
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13
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Abstract
Pluripotent stem cells (PSCs) can self-renew indefinitely in culture while retaining the potential to differentiate into virtually all normal cell types in the adult animal. Due to these remarkable properties, PSCs not only provide a superb system to investigate mammalian development and model diseases, but also hold promise for regenerative therapies. Autophagy is a self-digestive process that targets proteins, organelles, and other cellular contents for lysosomal degradation. Here, we review recent literature on the mechanistic role of different types of autophagy in embryonic development, embryonic stem cells (ESCs), and induced PSCs (iPSCs), focusing on their remodeling functions on protein, metabolism, and epigenetics. We present a perspective on unsolved issues and propose that autophagy is a promising target to modulate acquisition, maintenance, and directed differentiation of PSCs.
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Affiliation(s)
- Yi Xu
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China.
| | - Xiaolu Yang
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
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14
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Shi G, Chiramel AI, Li T, Lai KK, Kenney AD, Zani A, Eddy A, Majdoul S, Zhang L, Dempsey T, Beare PA, Kar S, Yewdell JW, Best SM, Yount JS, Compton AA. Rapalogs downmodulate intrinsic immunity and promote cell entry of SARS-CoV-2. bioRxiv 2022:2021.04.15.440067. [PMID: 33880473 PMCID: PMC8057238 DOI: 10.1101/2021.04.15.440067] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SARS-CoV-2 infection in immunocompromised individuals is associated with prolonged virus shedding and evolution of viral variants. Rapamycin and its analogs (rapalogs, including everolimus, temsirolimus, and ridaforolimus) are FDA-approved as mTOR inhibitors for the treatment of human diseases, including cancer and autoimmunity. Rapalog use is commonly associated with increased susceptibility to infection, which has been traditionally explained by impaired adaptive immunity. Here, we show that exposure to rapalogs increases susceptibility to SARS-CoV-2 infection in tissue culture and in immunologically naive rodents by antagonizing the cell-intrinsic immune response. By identifying one rapalog (ridaforolimus) that is less potent in this regard, we demonstrate that rapalogs promote Spike-mediated entry into cells by triggering the degradation of antiviral proteins IFITM2 and IFITM3 via an endolysosomal remodeling program called microautophagy. Rapalogs that increase virus entry inhibit the mTOR-mediated phosphorylation of the transcription factor TFEB, which facilitates its nuclear translocation and triggers microautophagy. In rodent models of infection, injection of rapamycin prior to and after virus exposure resulted in elevated SARS-CoV-2 replication and exacerbated viral disease, while ridaforolimus had milder effects. Overall, our findings indicate that preexisting use of certain rapalogs may elevate host susceptibility to SARS-CoV-2 infection and disease by activating lysosome-mediated suppression of intrinsic immunity.
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Affiliation(s)
- Guoli Shi
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Abhilash I. Chiramel
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA
| | - Tiansheng Li
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Kin Kui Lai
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Adam D. Kenney
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
| | - Ashley Zani
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
| | - Adrian Eddy
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
| | - Saliha Majdoul
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Lizhi Zhang
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
| | - Tirhas Dempsey
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Paul A. Beare
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA
| | | | - Jonathan W. Yewdell
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Sonja M. Best
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA
| | - Jacob S. Yount
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
| | - Alex A. Compton
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
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15
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Fairman G, Ouimet M. Lipophagy pathways in yeast are controlled by their distinct modes of induction. Yeast 2022; 39:429-439. [PMID: 35652813 DOI: 10.1002/yea.3705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/18/2022] [Accepted: 04/04/2022] [Indexed: 11/06/2022] Open
Abstract
Lipid droplet (LD) autophagy (lipophagy) is a recently discovered selective form of autophagy and is a pathway for LD catabolism. This ubiquitous process has been an ongoing area of research within the budding yeast, Saccharomyces cerevisiae. Yeast lipophagy phenotypically resembles microautophagy, although it has a distinct set of genetic requirements depending on the mode of induction. This review highlights the similarities and differences between different forms of yeast lipophagy and offers perspectives on how our knowledge of lipophagy in yeast may guide our understanding of this process within mammalian cells to ultimately inform future applications of lipophagy.
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Affiliation(s)
- Garrett Fairman
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mireille Ouimet
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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16
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Tasnin MN, Ito K, Katsuta H, Takuma T, Sharmin T, Ushimaru T. The PI3 Kinase Complex II-PI3P-Vps27 Axis on Vacuolar Membranes is Critical for Microautophagy Induction and Nutrient Stress Adaptation. J Mol Biol 2021; 434:167360. [PMID: 34798133 DOI: 10.1016/j.jmb.2021.167360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 12/27/2022]
Abstract
Phosphatidylinositol 3-phosphate (PI3P), a scaffold of membrane-associated proteins required for diverse cellular events, is produced by Vps34-containing phosphatidylinositol 3-kinase (PI3K). PI3K complex I (PI3KCI)-generated PI3P is required for macroautophagy, whereas PI3K complex II (PI3KCII)-generated PI3P is required for endosomal sorting complex required for transport (ESCRT)-mediated multi-vesicular body (MVB) formation in late endosomes. ESCRT also promotes vacuolar membrane remodeling in microautophagy after nutrient starvation and inactivation of target of rapamycin complex 1 (TORC1) protein kinase in budding yeast. Whereas PI3KCI and macroautophagy are critical for the nutrient starvation response, the physiological roles of PI3KCII and microautophagy during starvation are largely unknown. Here, we showed that PI3KCII-produced PI3P on vacuolar membranes is required for microautophagy induction and survival in nutrient-stressed conditions. PI3KCII is required for Vps27 (an ESCRT-0 component) recruitment and ESCRT-0 complex formation on vacuolar surfaces after TORC1 inactivation. Forced recruitment of Vps27 onto vacuolar membranes rescued the defect in microautophagy induction in PI3KCII-deficient cells, indicating that a critical role of PI3P on microautophagy induction is Vps27 recruitment onto vacuolar surfaces. Finally, vacuolar membrane-associated Vps27 was able to recover survival during nutrient starvation in cells lacking PI3KCII or Vps27. This study revealed that the PI3KCII-PI3P-Vps27 axis on vacuolar membranes is critical for ESCRT-mediated microautophagy induction and nutrient stress adaptation.
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Affiliation(s)
- Most Naoshia Tasnin
- Graduate School of Science and Technology, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan
| | - Kisara Ito
- Department of Bioscience, Faculty of Science, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan
| | - Haruko Katsuta
- Course of Biological Science, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan
| | - Tsuneyuki Takuma
- Course of Biological Science, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan
| | - Tasnuva Sharmin
- Graduate School of Science and Technology, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan
| | - Takashi Ushimaru
- Graduate School of Science and Technology, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan; Department of Bioscience, Faculty of Science, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan; Course of Biological Science, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8021, Japan.
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17
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Trelford CB, Di Guglielmo GM. Molecular mechanisms of mammalian autophagy. Biochem J 2021; 478:3395-421. [PMID: 34554214 DOI: 10.1042/BCJ20210314] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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18
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Robert G, Yagyu M, Lascano HR, Masclaux-Daubresse C, Yoshimoto K. A proposed role for endomembrane trafficking processes in regulating tonoplast content and vacuole dynamics under ammonium stress conditions in Arabidopsis root cells. Plant Signal Behav 2021; 16:1924977. [PMID: 33955336 PMCID: PMC8280891 DOI: 10.1080/15592324.2021.1924977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
Ammonium (NH4+) stress has multiple effects on plant physiology, therefore, plant responses are complex, and multiple mechanisms are involved in NH4+ sensitivity and tolerance in plants. Root growth inhibition is an important quantitative readout of the effects of NH4+ stress on plant physiology, and cell elongation appear as the principal growth inhibition target. We recently proposed autophagy as a relevant physiological mechanisms underlying NH4+ sensitivity response in Arabidopsis. In a brief overview, the impaired macro-autophagic flux observed under NH4+ stress conditions has a detrimental impact on the cellular energetic balance, and therefore on the energy-demanding plant growth. In contrast to its inhibitory effect on the autophagosomes flux to vacuole, NH4+ toxicity induced a micro-autophagy-like process. Consistent with the reduced membrane flux to the vacuole related to macro-autophagy inhibition and the increased tonoplast degradation due to enhanced micro-autophagy, the vacuoles of the root cells of the NH4+-stressed plants showed lower tonoplast content and a decreased perimeter/area ratio. As the endosome-to-vacuole trafficking is another important process that contributes to membrane flux toward the vacuole, we evaluated the effects of NH4+ stress on this process. This allows us to propose that autophagy could contribute to vacuole development as well as possible avenues to follow for future studies.
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Affiliation(s)
- Germán Robert
- Plant Stress Biology Group, Unidad de Doble Dependencia INTA-CONICET (UDEA), Córdoba, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Córdoba, Argentina
- Cátedra de Fisiología Vegetal, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mako Yagyu
- Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
| | - Hernán Ramiro Lascano
- Plant Stress Biology Group, Unidad de Doble Dependencia INTA-CONICET (UDEA), Córdoba, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Córdoba, Argentina
- Cátedra de Fisiología Vegetal, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | - Kohki Yoshimoto
- Department of Life Sciences, School of Agriculture, Meiji University, Kanagawa, Japan
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19
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Mesquita A, Glenn J, Jenny A. Differential activation of eMI by distinct forms of cellular stress. Autophagy 2021; 17:1828-1840. [PMID: 32559125 PMCID: PMC8386722 DOI: 10.1080/15548627.2020.1783833] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 06/03/2020] [Accepted: 06/08/2020] [Indexed: 12/11/2022] Open
Abstract
As one of the major, highly conserved catabolic pathways, autophagy delivers cytosolic components to lysosomes for degradation. It is essential for development, cellular homeostasis, and coping with stress. Reduced autophagy increases susceptibility to protein aggregation diseases and leads to phenotypes associated with aging. Of the three major forms of autophagy, macroautophagy (MA) can degrade organelles or aggregated proteins, and chaperone-mediated autophagy is specific for soluble proteins containing KFERQ-related targeting motifs. During endosomal microautophagy (eMI), cytoplasmic proteins are engulfed into late endosomes in an ESCRT machinery-dependent manner. eMI can be KFERQ-specific or occur in bulk and be induced by prolonged starvation. Its physiological regulation and function, however, are not understood. Here, we show that eMI in the Drosophila fat body, akin to the mammalian liver, is induced upon oxidative or genotoxic stress in an ESCRT and partially Hsc70-4-dependent manner. Interestingly, eMI activation is selective, as ER stress fails to elicit a response. Intriguingly, we find that reducing MA leads to a compensatory enhancement of eMI, suggesting a tight interplay between these degradative processes. Furthermore, we show that mutations in DNA damage response genes are sufficient to trigger eMI and that the response to oxidative stress is under the control of MAPK/JNK signaling. Our data suggest that, controlled by various signaling pathways, eMI allows an organ to react and adapt to specific types of stress and is thus likely critical to prevent disease.Abbreviations:Atg: autophagy-related; CMA: chaperone-mediated autophagy; DDR: DNA damage repair; Df: deficiency (deletion); (E)GFP: (enhanced) green fluorescent protein; eMI: endosomal microautophagy; ER: endoplasmatic reticulum; ESCRT: endosomal sorting complexes required for transport; Eto: etoposide; FLP: flipase; Hsc: heat shock cognate protein; LAMP2A: lysosomal-associated membrane protein 2A; LE: late endosome; MA: macroautophagy; MI: microautophagy; MVB: multivesicular body; PA: photoactivatable; Para: paraquat; ROS: reactive oxygen species; SEM: standard error of means; Tor: target of rapamycin [serine/threonine kinase]; UPR: unfolded protein response; Vps: vacuolar protein sorting.
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Affiliation(s)
- Ana Mesquita
- Department of Developmental and Molecular Biology, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, New York, NY, US
| | - James Glenn
- Department of Developmental and Molecular Biology, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, New York, NY, US
| | - Andreas Jenny
- Department of Developmental and Molecular Biology, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, New York, NY, US
- Department of Genetics, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, New York, NY, US
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine, New York, NY, US
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20
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Rahman MA, Kumar R, Sanchez E, Nazarko TY. Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains. Int J Mol Sci 2021; 22:8144. [PMID: 34360917 PMCID: PMC8348048 DOI: 10.3390/ijms22158144] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 01/01/2023] Open
Abstract
Although once perceived as inert structures that merely serve for lipid storage, lipid droplets (LDs) have proven to be the dynamic organelles that hold many cellular functions. The LDs' basic structure of a hydrophobic core consisting of neutral lipids and enclosed in a phospholipid monolayer allows for quick lipid accessibility for intracellular energy and membrane production. Whereas formed at the peripheral and perinuclear endoplasmic reticulum, LDs are degraded either in the cytosol by lipolysis or in the vacuoles/lysosomes by autophagy. Autophagy is a regulated breakdown of dysfunctional, damaged, or surplus cellular components. The selective autophagy of LDs is called lipophagy. Here, we review LDs and their degradation by lipophagy in yeast, which proceeds via the micrometer-scale raft-like lipid domains in the vacuolar membrane. These vacuolar microdomains form during nutrient deprivation and facilitate internalization of LDs via the vacuolar membrane invagination and scission. The resultant intra-vacuolar autophagic bodies with LDs inside are broken down by vacuolar lipases and proteases. This type of lipophagy is called microlipophagy as it resembles microautophagy, the type of autophagy when substrates are sequestered right at the surface of a lytic compartment. Yeast microlipophagy via the raft-like vacuolar microdomains is a great model system to study the role of lipid domains in microautophagic pathways.
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Affiliation(s)
- Muhammad Arifur Rahman
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
| | - Ravinder Kumar
- Department of Obstetrics, Gynecology and Reproductive Science, University of California, San Francisco, CA 94143, USA;
| | - Enrique Sanchez
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Taras Y. Nazarko
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA; (M.A.R.); (E.S.)
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21
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Lemus L, Matić Z, Gal L, Fadel A, Schuldiner M, Goder V. Post-ER degradation of misfolded GPI-anchored proteins is linked with microautophagy. Curr Biol 2021; 31:4025-4037.e5. [PMID: 34314677 DOI: 10.1016/j.cub.2021.06.078] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/07/2021] [Accepted: 06/25/2021] [Indexed: 01/08/2023]
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are membrane-conjugated cell-surface proteins with diverse structural, developmental, and signaling functions and clinical relevance. Typically, after biosynthesis and attachment to the preassembled GPI anchor, GPI-APs rapidly leave the endoplasmic reticulum (ER) and rely on post-ER quality control. Terminally misfolded GPI-APs end up inside the vacuole/lysosome for degradation, but their trafficking itinerary to this organelle and the processes linked to their uptake by the vacuole/lysosome remain uncharacterized. In a yeast mutant that is lacking Pep4, a key vacuolar protease, several misfolded model GPI-APs accumulated in the vacuolar membrane. In the same mutant, macroautophagy and the multi-vesicular body (MVB) pathway were intact, hinting at a hitherto-unknown trafficking pathway for the degradation of misfolded GPI-APs. To unravel it, we used a genome-wide screen coupled to high-throughput fluorescence microscopy and followed the fate of the misfolded GPI-AP: Gas1∗. We found that components of the early secretory and endocytic pathways are involved in its targeting to the vacuole and that vacuolar transporter chaperones (VTCs), with roles in microautophagy, negatively affect the vacuolar uptake of Gas1∗. In support, we demonstrate that Gas1∗ internalizes from vacuolar membranes into membrane-bound intravacuolar vesicles prior to degradation. Our data link post-ER degradation with microautophagy.
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Affiliation(s)
- Leticia Lemus
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
| | - Zrinka Matić
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain
| | - Lihi Gal
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Amir Fadel
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Meyer Bldg. Room 122, Weizmann Institute of Sciences, 76100 Rehovot, Israel
| | - Veit Goder
- Department of Genetics, University of Seville, Ave Reina Mercedes, 6, 41012 Seville, Spain.
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22
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Kawamura N, Takaoka K, Hamada H, Hadjantonakis AK, Sun-Wada GH, Wada Y. Rab7-Mediated Endocytosis Establishes Patterning of Wnt Activity through Inactivation of Dkk Antagonism. Cell Rep 2021; 31:107733. [PMID: 32521258 PMCID: PMC8171381 DOI: 10.1016/j.celrep.2020.107733] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 03/16/2020] [Accepted: 05/13/2020] [Indexed: 12/12/2022] Open
Abstract
Endocytosis has been proposed to modulate cell signaling activities. However, the role of endocytosis in embryogenesis, which requires coordination of multiple signaling inputs, has remained less understood. We previously showed that mouse embryos lacking a small guanosine triphosphate (GTP)-binding protein Rab7 implicated in endocytic flow are defective in gastrulation. Here, we investigate how subcellular defects associated with Rab7 deficiency are related to the observed developmental defects. Rab7-deficient embryos fail to organize mesodermal tissues due to defects in Wnt-β-catenin signaling. Visceral endoderm (VE)-specific ablation of Rab7 results in patterning defects similar to systemic Rab7 deletion. Rab7 mutants accumulate the Wnt antagonist Dkk1 in the extracellular space and in intracellular compartments throughout the VE epithelium. These data indicate that Rab7-dependent endocytosis regulates the concentration and availability of extracellular Dkk1, thereby relieving the epiblast of antagonism. This intercellular mechanism therefore organizes distinct spatiotemporal patterns of canonical Wnt activity during the peri-gastrulation stages of embryonic development.
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Affiliation(s)
- Nobuyuki Kawamura
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kohdo, Kyotanabe, Kyoto 610-0395, Japan
| | - Katsuyoshi Takaoka
- Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Hiroshi Hamada
- RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan; Developmental Genetics Group, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ge-Hong Sun-Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kohdo, Kyotanabe, Kyoto 610-0395, Japan.
| | - Yoh Wada
- Division of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
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23
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Filali-Mouncef Y, Hunter C, Roccio F, Zagkou S, Dupont N, Primard C, Proikas-Cezanne T, Reggiori F. The ménage à trois of autophagy, lipid droplets and liver disease. Autophagy 2021; 18:50-72. [PMID: 33794741 PMCID: PMC8865253 DOI: 10.1080/15548627.2021.1895658] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Autophagic pathways cross with lipid homeostasis and thus provide energy and essential building blocks that are indispensable for liver functions. Energy deficiencies are compensated by breaking down lipid droplets (LDs), intracellular organelles that store neutral lipids, in part by a selective type of autophagy, referred to as lipophagy. The process of lipophagy does not appear to be properly regulated in fatty liver diseases (FLDs), an important risk factor for the development of hepatocellular carcinomas (HCC). Here we provide an overview on our current knowledge of the biogenesis and functions of LDs, and the mechanisms underlying their lysosomal turnover by autophagic processes. This review also focuses on nonalcoholic steatohepatitis (NASH), a specific type of FLD characterized by steatosis, chronic inflammation and cell death. Particular attention is paid to the role of macroautophagy and macrolipophagy in relation to the parenchymal and non-parenchymal cells of the liver in NASH, as this disease has been associated with inappropriate lipophagy in various cell types of the liver.Abbreviations: ACAT: acetyl-CoA acetyltransferase; ACAC/ACC: acetyl-CoA carboxylase; AKT: AKT serine/threonine kinase; ATG: autophagy related; AUP1: AUP1 lipid droplet regulating VLDL assembly factor; BECN1/Vps30/Atg6: beclin 1; BSCL2/seipin: BSCL2 lipid droplet biogenesis associated, seipin; CMA: chaperone-mediated autophagy; CREB1/CREB: cAMP responsive element binding protein 1; CXCR3: C-X-C motif chemokine receptor 3; DAGs: diacylglycerols; DAMPs: danger/damage-associated molecular patterns; DEN: diethylnitrosamine; DGAT: diacylglycerol O-acyltransferase; DNL: de novo lipogenesis; EHBP1/NACSIN (EH domain binding protein 1); EHD2/PAST2: EH domain containing 2; CoA: coenzyme A; CCL/chemokines: chemokine ligands; CCl4: carbon tetrachloride; ER: endoplasmic reticulum; ESCRT: endosomal sorting complexes required for transport; FA: fatty acid; FFAs: free fatty acids; FFC: high saturated fats, fructose and cholesterol; FGF21: fibroblast growth factor 21; FITM/FIT: fat storage inducing transmembrane protein; FLD: fatty liver diseases; FOXO: forkhead box O; GABARAP: GABA type A receptor-associated protein; GPAT: glycerol-3-phosphate acyltransferase; HCC: hepatocellular carcinoma; HDAC6: histone deacetylase 6; HECT: homologous to E6-AP C-terminus; HFCD: high fat, choline deficient; HFD: high-fat diet; HSCs: hepatic stellate cells; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; ITCH/AIP4: itchy E3 ubiquitin protein ligase; KCs: Kupffer cells; LAMP2A: lysosomal associated membrane protein 2A; LDs: lipid droplets; LDL: low density lipoprotein; LEP/OB: leptin; LEPR/OBR: leptin receptor; LIPA/LAL: lipase A, lysosomal acid type; LIPE/HSL: lipase E, hormone sensitive type; LIR: LC3-interacting region; LPS: lipopolysaccharide; LSECs: liver sinusoidal endothelial cells; MAGs: monoacylglycerols; MAPK: mitogen-activated protein kinase; MAP3K5/ASK1: mitogen-activated protein kinase kinase kinase 5; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MCD: methionine-choline deficient; MGLL/MGL: monoglyceride lipase; MLXIPL/ChREBP: MLX interacting protein like; MTORC1: mechanistic target of rapamycin kinase complex 1; NAFLD: nonalcoholic fatty liver disease; NAS: NAFLD activity score; NASH: nonalcoholic steatohepatitis; NPC: NPC intracellular cholesterol transporter; NR1H3/LXRα: nuclear receptor subfamily 1 group H member 3; NR1H4/FXR: nuclear receptor subfamily 1 group H member 4; PDGF: platelet derived growth factor; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PLIN: perilipin; PNPLA: patatin like phospholipase domain containing; PNPLA2/ATGL: patatin like phospholipase domain containing 2; PNPLA3/adiponutrin: patatin like phospholipase domain containing 3; PPAR: peroxisome proliferator activated receptor; PPARA/PPARα: peroxisome proliferator activated receptor alpha; PPARD/PPARδ: peroxisome proliferator activated receptor delta; PPARG/PPARγ: peroxisome proliferator activated receptor gamma; PPARGC1A/PGC1α: PPARG coactivator 1 alpha; PRKAA/AMPK: protein kinase AMP-activated catalytic subunit; PtdIns3K: class III phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PTEN: phosphatase and tensin homolog; ROS: reactive oxygen species; SE: sterol esters; SIRT1: sirtuin 1; SPART/SPG20: spartin; SQSTM1/p62: sequestosome 1; SREBF1/SREBP1c: sterol regulatory element binding transcription factor 1; TAGs: triacylglycerols; TFE3: transcription factor binding to IGHM enhancer 3; TFEB: transcription factor EB; TGFB1/TGFβ: transforming growth factor beta 1; Ub: ubiquitin; UBE2G2/UBC7: ubiquitin conjugating enzyme E2 G2; ULK1/Atg1: unc-51 like autophagy activating kinase 1; USF1: upstream transcription factor 1; VLDL: very-low density lipoprotein; VPS: vacuolar protein sorting; WIPI: WD-repeat domain, phosphoinositide interacting; WDR: WD repeat domain.
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Affiliation(s)
- Yasmina Filali-Mouncef
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
| | - Catherine Hunter
- Interfaculty Institute of Cell Biology, Eberhard Karls University Tuebingen, Tuebingen, Germany.,International Max Planck Research School 'From Molecules to Organisms', Max Planck Institute for Developmental Biology and Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Federica Roccio
- Institut Necker Enfants-Malades (INEM), INSERM U1151-CNRS UMR 8253, Université de Paris, Paris, France
| | - Stavroula Zagkou
- Adjuvatis, Lyon, France.,Laboratory of Tissue Biology and Therapeutic Engineering, CNRS UMR 5305, Université Claude Bernard Lyon 1, France
| | - Nicolas Dupont
- Institut Necker Enfants-Malades (INEM), INSERM U1151-CNRS UMR 8253, Université de Paris, Paris, France
| | | | - Tassula Proikas-Cezanne
- Interfaculty Institute of Cell Biology, Eberhard Karls University Tuebingen, Tuebingen, Germany.,International Max Planck Research School 'From Molecules to Organisms', Max Planck Institute for Developmental Biology and Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
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Dejgaard SY, Presley JF. Interactions of Lipid Droplets with the Intracellular Transport Machinery. Int J Mol Sci 2021; 22:2776. [PMID: 33803444 DOI: 10.3390/ijms22052776] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 02/27/2021] [Accepted: 02/27/2021] [Indexed: 12/16/2022] Open
Abstract
Historically, studies of intracellular membrane trafficking have focused on the secretory and endocytic pathways and their major organelles. However, these pathways are also directly implicated in the biogenesis and function of other important intracellular organelles, the best studied of which are peroxisomes and lipid droplets. There is a large recent body of work on these organelles, which have resulted in the introduction of new paradigms regarding the roles of membrane trafficking organelles. In this review, we discuss the roles of membrane trafficking in the life cycle of lipid droplets. This includes the complementary roles of lipid phase separation and proteins in the biogenesis of lipid droplets from endoplasmic reticulum (ER) membranes, and the attachment of mature lipid droplets to membranes by lipidic bridges and by more conventional protein tethers. We also discuss the catabolism of neutral lipids, which in part results from the interaction of lipid droplets with cytosolic molecules, but with important roles for both macroautophagy and microautophagy. Finally, we address their eventual demise, which involves interactions with the autophagocytotic machinery. We pay particular attention to the roles of small GTPases, particularly Rab18, in these processes.
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Robert G, Yagyu M, Koizumi T, Naya L, Masclaux-Daubresse C, Yoshimoto K. Ammonium stress increases microautophagic activity while impairing macroautophagic flux in Arabidopsis roots. Plant J 2021; 105:1083-1097. [PMID: 33222335 DOI: 10.1111/tpj.15091] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 06/11/2023]
Abstract
Plant responses to NH4+ stress are complex, and multiple mechanisms underlying NH4+ sensitivity and tolerance in plants may be involved. Here, we demonstrate that macro- and microautophagic activities are oppositely affected in plants grown under NH4+ toxicity conditions. When grown under NH4+ stress conditions, macroautophagic activity was impaired in roots. Root cells accumulated autophagosomes in the cytoplasm, but showed less autophagic flux, indicating that late steps of the macroautophagy process are affected under NH4+ stress conditions. Under this scenario, we also found that the CCZ1-MON1 complex, a critical factor for vacuole delivery pathways, functions in the late step of the macroautophagic pathway in Arabidopsis. In contrast, an accumulation of tonoplast-derived vesicles was observed in vacuolar lumens of root cells of NH4+ -stressed plants, suggesting the induction of a microautophagy-like process. In this sense, some SYP22-, but mainly VAMP711-positive vesicles were observed inside vacuole in roots of NH4+ -stressed plants. Consistent with the increased tonoplast degradation and the reduced membrane flow to the vacuole due to the impaired macroautophagic flux, the vacuoles of root cells of NH4+ -stressed plants showed a simplified structure and lower tonoplast content. Taken together, this study presents evidence that postulates late steps of the macroautophagic process as a relevant physiological mechanism underlying the NH4+ sensitivity response in Arabidopsis, and additionally provides insights into the molecular tools for studying microautophagy in plants.
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Affiliation(s)
- Germán Robert
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, 78000, France
- Instituto Nacional de Tecnología Agropecuaria (INTA) - Instituto de Fisiología y Recursos Genéticos Vegetales (IFRGV), Av. 11 de Septiembre, Córdoba, 4755-X5020ICA, Argentina
- Unidad de doble dependencia INTA-CONICET (UDEA), Av. 11 de Septiembre, Córdoba, 4755-X5020ICA, Argentina
| | - Mako Yagyu
- Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki-shi, Kanagawa, 214-8571, Japan
| | - Takaya Koizumi
- Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki-shi, Kanagawa, 214-8571, Japan
| | - Loreto Naya
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, 78000, France
| | - Céline Masclaux-Daubresse
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, 78000, France
| | - Kohki Yoshimoto
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, 78000, France
- Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-ku, Kawasaki-shi, Kanagawa, 214-8571, Japan
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Lee C, Overholtzer M. Getting picky with the lysosome membrane. Autophagy 2021; 17:1034-1036. [PMID: 33499722 DOI: 10.1080/15548627.2021.1877935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Lysosomes play an essential role in quality control mechanisms by functioning as the primary digestive system in mammalian cells. However, the quality control mechanisms governing healthy lysosomes are not fully understood. Using a method to study lysosome membrane turnover, we discovered that LC3-lipidation on the lysosome limiting membrane is involved in invagination and formation of intralumenal vesicles, an activity known as microautophagy. This activity occurs in response to metabolic stress, in the form of glucose starvation, or osmotic stress induced by treatment with lysosomotropic compounds. Cells rendered deficient in the ability to lipidate LC3 through knockout of ATG5 show reduced ability to regulate lysosome size and degradative function in response to stress. These findings demonstrate that cells can adapt to changing metabolic conditions by turning over selective portions of the lysosomal membrane, using a mechanism that involves lysosome-targeted LC3 lipidation and the induction of selective microautophagy.
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Affiliation(s)
- Chan Lee
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY, USA.,BCMB Allied Program, Weill Cornell Medical College, New York, NY, USA
| | - Michael Overholtzer
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY, USA.,BCMB Allied Program, Weill Cornell Medical College, New York, NY, USA.,Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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Abstract
Hepatocytes metabolize energy-rich cytoplasmic lipid droplets (LDs) in the lysosome-directed process of autophagy. An organelle-selective form of this process (macrolipophagy) results in the engulfment of LDs within double-membrane delimited structures (autophagosomes) before lysosomal fusion. Whether this is an exclusive autophagic mechanism used by hepatocytes to catabolize LDs is unclear. It is also unknown whether lysosomes alone might be sufficient to mediate LD turnover in the absence of an autophagosomal intermediate. We performed live-cell microscopy of hepatocytes to monitor the dynamic interactions between lysosomes and LDs in real-time. We additionally used a fluorescent variant of the LD-specific protein (PLIN2) that exhibits altered fluorescence in response to LD interactions with the lysosome. We find that mammalian lysosomes and LDs undergo interactions during which proteins and lipids can be transferred from LDs directly into lysosomes. Electron microscopy (EM) of primary hepatocytes or hepatocyte-derived cell lines supports the existence of these interactions. It reveals a dramatic process whereby the lipid contents of the LD can be "extruded" directly into the lysosomal lumen under nutrient-limited conditions. Significantly, these interactions are not affected by perturbations to crucial components of the canonical macroautophagy machinery and can occur in the absence of double-membrane lipoautophagosomes. These findings implicate the existence of an autophagic mechanism used by mammalian cells for the direct transfer of LD components into the lysosome for breakdown. This process further emphasizes the critical role of lysosomes in hepatic LD catabolism and provides insights into the mechanisms underlying lipid homeostasis in the liver.
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Affiliation(s)
- Ryan J Schulze
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Eugene W Krueger
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Shaun G Weller
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Katherine M Johnson
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Carol A Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198
| | - Micah B Schott
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
| | - Mark A McNiven
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905;
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905
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Coelho BP, Fernandes CFDL, Boccacino JM, Souza MCDS, Melo-Escobar MI, Alves RN, Prado MB, Iglesia RP, Cangiano G, Mazzaro GLR, Lopes MH. Multifaceted WNT Signaling at the Crossroads Between Epithelial-Mesenchymal Transition and Autophagy in Glioblastoma. Front Oncol 2020; 10:597743. [PMID: 33312955 PMCID: PMC7706883 DOI: 10.3389/fonc.2020.597743] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/19/2020] [Indexed: 12/17/2022] Open
Abstract
Tumor cells can employ epithelial-mesenchymal transition (EMT) or autophagy in reaction to microenvironmental stress. Importantly, EMT and autophagy negatively regulate each other, are able to interconvert, and both have been shown to contribute to drug-resistance in glioblastoma (GBM). EMT has been considered one of the mechanisms that confer invasive properties to GBM cells. Autophagy, on the other hand, may show dual roles as either a GBM-promoter or GBM-suppressor, depending on microenvironmental cues. The Wingless (WNT) signaling pathway regulates a plethora of developmental and biological processes such as cellular proliferation, adhesion and motility. As such, GBM demonstrates deregulation of WNT signaling in favor of tumor initiation, proliferation and invasion. In EMT, WNT signaling promotes induction and stabilization of different EMT activators. WNT activity also represses autophagy, while nutrient deprivation induces β-catenin degradation via autophagic machinery. Due to the importance of the WNT pathway to GBM, and the role of WNT signaling in EMT and autophagy, in this review we highlight the effects of the WNT signaling in the regulation of both processes in GBM, and discuss how the crosstalk between EMT and autophagy may ultimately affect tumor biology.
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Affiliation(s)
- Bárbara Paranhos Coelho
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Camila Felix de Lima Fernandes
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Jacqueline Marcia Boccacino
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Maria Clara da Silva Souza
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Maria Isabel Melo-Escobar
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Rodrigo Nunes Alves
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Mariana Brandão Prado
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Rebeca Piatniczka Iglesia
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Giovanni Cangiano
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Giulia La Rocca Mazzaro
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
| | - Marilene Hohmuth Lopes
- Laboratory of Neurobiology and Stem Cells, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, São Paulo, Brazil
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Garcia EJ, Liao PC, Tan G, Vevea JD, Sing CN, Tsang CA, McCaffery JM, Boldogh IR, Pon LA. Membrane dynamics and protein targets of lipid droplet microautophagy during ER stress-induced proteostasis in the budding yeast, Saccharomyces cerevisiae. Autophagy 2020. [PMID: 33021864 DOI: 10.1080/15548627.2020.1826691.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022] Open
Abstract
Our previous studies reveal a mechanism for lipid droplet (LD)-mediated proteostasis in the endoplasmic reticulum (ER) whereby unfolded proteins that accumulate in the ER in response to lipid imbalance-induced ER stress are removed by LDs and degraded by microlipophagy (µLP), autophagosome-independent LD uptake into the vacuole (the yeast lysosome). Here, we show that dithiothreitol- or tunicamycin-induced ER stress also induces µLP and identify an unexpected role for vacuolar membrane dynamics in this process. All stressors studied induce vacuolar fragmentation prior to µLP. Moreover, during µLP, fragmented vacuoles fuse to form cup-shaped structures that encapsulate and ultimately take up LDs. Our studies also indicate that proteins of the endosome sorting complexes required for transport (ESCRT) are upregulated, required for µLP, and recruited to LDs, vacuolar membranes, and sites of vacuolar membrane scission during µLP. We identify possible target proteins for LD-mediated ER proteostasis. Our live-cell imaging studies reveal that one potential target (Nup159) localizes to punctate structures that colocalizes with LDs 1) during movement from ER membranes to the cytosol, 2) during microautophagic uptake into vacuoles, and 3) within the vacuolar lumen. Finally, we find that mutations that inhibit LD biogenesis, homotypic vacuolar membrane fusion or ESCRT function inhibit stress-induced autophagy of Nup159 and other ER proteins. Thus, we have obtained the first direct evidence that LDs and µLP can mediate ER stress-induced ER proteostasis, and identified direct roles for ESCRT and vacuolar membrane fusion in that process.
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Affiliation(s)
- Enrique J Garcia
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Pin-Chao Liao
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Gary Tan
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Jason D Vevea
- HHMI and Department of Neuroscience, University of Wisconsin, Madison, Wisconsin, USA
| | - Cierra N Sing
- Institute of Human Nutrition, Columbia University, New York, NY, USA
| | - Catherine A Tsang
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - J Michael McCaffery
- Integrated Imaging Center, Department of Biology, The Johns Hopkins University, Baltimore, MD, USA
| | - Istvan R Boldogh
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
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30
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Garcia EJ, Liao PC, Tan G, Vevea JD, Sing CN, Tsang CA, McCaffery JM, Boldogh IR, Pon LA. Membrane dynamics and protein targets of lipid droplet microautophagy during ER stress-induced proteostasis in the budding yeast, Saccharomyces cerevisiae. Autophagy 2020; 17:2363-2383. [PMID: 33021864 PMCID: PMC8496710 DOI: 10.1080/15548627.2020.1826691] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Our previous studies reveal a mechanism for lipid droplet (LD)-mediated proteostasis in the endoplasmic reticulum (ER) whereby unfolded proteins that accumulate in the ER in response to lipid imbalance-induced ER stress are removed by LDs and degraded by microlipophagy (µLP), autophagosome-independent LD uptake into the vacuole (the yeast lysosome). Here, we show that dithiothreitol- or tunicamycin-induced ER stress also induces µLP and identify an unexpected role for vacuolar membrane dynamics in this process. All stressors studied induce vacuolar fragmentation prior to µLP. Moreover, during µLP, fragmented vacuoles fuse to form cup-shaped structures that encapsulate and ultimately take up LDs. Our studies also indicate that proteins of the endosome sorting complexes required for transport (ESCRT) are upregulated, required for µLP, and recruited to LDs, vacuolar membranes, and sites of vacuolar membrane scission during µLP. We identify possible target proteins for LD-mediated ER proteostasis. Our live-cell imaging studies reveal that one potential target (Nup159) localizes to punctate structures that colocalizes with LDs 1) during movement from ER membranes to the cytosol, 2) during microautophagic uptake into vacuoles, and 3) within the vacuolar lumen. Finally, we find that mutations that inhibit LD biogenesis, homotypic vacuolar membrane fusion or ESCRT function inhibit stress-induced autophagy of Nup159 and other ER proteins. Thus, we have obtained the first direct evidence that LDs and µLP can mediate ER stress-induced ER proteostasis, and identified direct roles for ESCRT and vacuolar membrane fusion in that process.
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Affiliation(s)
- Enrique J Garcia
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Pin-Chao Liao
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Gary Tan
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Jason D Vevea
- HHMI and Department of Neuroscience, University of Wisconsin, Madison, Wisconsin, USA
| | - Cierra N Sing
- Institute of Human Nutrition, Columbia University, New York, NY, USA
| | - Catherine A Tsang
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - J Michael McCaffery
- Integrated Imaging Center, Department of Biology, The Johns Hopkins University, Baltimore, MD, USA
| | - Istvan R Boldogh
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
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Lee C, Lamech L, Johns E, Overholtzer M. Selective Lysosome Membrane Turnover Is Induced by Nutrient Starvation. Dev Cell 2020; 55:289-297.e4. [PMID: 32916093 DOI: 10.1016/j.devcel.2020.08.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/02/2020] [Accepted: 08/17/2020] [Indexed: 12/20/2022]
Abstract
Lysosome function is essential for cellular homeostasis, but quality-control mechanisms that maintain healthy lysosomes remain poorly characterized. Here, we developed a method to measure lysosome turnover and use this to identify a selective mechanism of membrane degradation that involves lipidation of the autophagy protein LC3 onto lysosomal membranes and the formation of intraluminal vesicles through microautophagy. This mechanism is induced in response to metabolic stress resulting from glucose starvation or by treatment with pharmacological agents that induce osmotic stress on lysosomes. Cells lacking ATG5, an essential component of the LC3 lipidation machinery, show reduced ability to regulate lysosome size and degradative capacity in response to activation of this mechanism. These findings identify a selective mechanism of lysosome membrane turnover that is induced by stress and uncover a function for LC3 lipidation in regulating lysosome size and activity through microautophagy.
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Affiliation(s)
- Chan Lee
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA; BCMB Allied Program, Weill Cornell Medical College, New York, NY 10065, USA
| | - Lilian Lamech
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA
| | - Eleanor Johns
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA; Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Michael Overholtzer
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA; BCMB Allied Program, Weill Cornell Medical College, New York, NY 10065, USA; Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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Abstract
INTRODUCTION Autophagy is an evolutionarily conserved cellular clearance process, by which cytosolic components are delivered to autolysosomes for breakdown and recycling to maintain cellular homeostasis. During the past decades, autophagy has been found to be tightly implicated in various physiological and pathological progresses. Unraveling the regulatory mechanisms of the autophagy process will contribute to the development of emerging autophagy-targeting strategies for the treatment of various diseases. Recently, the rapid development of proteomics approaches has enabled the use of large-scale unbiased strategies to unravel autophagy machinery. AREAS COVERED In this review, we will highlight the recent contributions of proteomics strategies in clarifying the autophagy machinery, with an emphasis on the three different types of autophagy (namely macroautophagy, microautophagy, and chaperone-mediated autophagy). We will also discuss the emerging role of proteomics approaches in investigating the mechanism of the autophagy-based unconventional secretory pathway (secretory autophagy). EXPERT OPINION Proteomics has provided an effective strategy for the comprehensive analysis of the autophagy process, which will broaden our understanding of autophagy machinery, and holds great promise for developing clinical therapies targeting autophagy.
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Affiliation(s)
- Xingyun Wu
- West China School of Basic Medical Sciences & Forensic Medicine, Center of Reproductive Medicine, West China Second University Hospital, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy , Chengdu, P.R. China
| | - Li Luo
- West China School of Basic Medical Sciences & Forensic Medicine, Center of Reproductive Medicine, West China Second University Hospital, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy , Chengdu, P.R. China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education , Chengdu, P.R. China
| | - Ruxin Kong
- West China School of Basic Medical Sciences & Forensic Medicine, Center of Reproductive Medicine, West China Second University Hospital, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy , Chengdu, P.R. China
| | - Yabing Song
- West China School of Basic Medical Sciences & Forensic Medicine, Center of Reproductive Medicine, West China Second University Hospital, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy , Chengdu, P.R. China
| | - Qifu Li
- Department of Neurology, the First Affiliated Hospital of Hainan Medical University, and Key Laboratory of Brain Science Research & Transformation in Tropical Environment of Hainan Province, Hainan Medical University , Haikou, P.R. China
| | - Edouard C Nice
- Department of Biochemistry and Molecular Biology, Monash University , Clayton, Australia
| | - Kui Wang
- West China School of Basic Medical Sciences & Forensic Medicine, Center of Reproductive Medicine, West China Second University Hospital, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy , Chengdu, P.R. China
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33
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Abstract
Nucleophagy, the selective subtype of autophagy that targets nuclear material for autophagic degradation, was not only shown to be a model system for the study of selective macroautophagy, but also for elucidating the role of the core autophagic machinery within microautophagy. Nucleophagy also emerged as a system associated with a variety of disease conditions including cancer, neurodegeneration and ageing. Nucleophagic processes are part of natural cell development, but also act as a response to various stress conditions. Upon releasing small portions of nuclear material, micronuclei, the autophagic machinery transfers these micronuclei to the vacuole for subsequent degradation. Despite sharing many cargos and requiring the core autophagic machinery, recent investigations revealed the aspects that set macro- and micronucleophagy apart. Central to the discrepancies found between macro- and micronucleophagy is the nucleus vacuole junction, a large membrane contact site formed between nucleus and vacuole. Exclusion of nuclear pore complexes from the junction and its exclusive degradation by micronucleophagy reveal compositional differences in cargo. Regarding their shared reliance on the core autophagic machinery, micronucleophagy does not involve normal autophagosome biogenesis observed for macronucleophagy, but instead maintains a unique role in overall microautophagy, with the autophagic machinery accumulating at the neck of budding vesicles.
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Sieńko K, Poormassalehgoo A, Yamada K, Goto-Yamada S. Microautophagy in Plants: Consideration of Its Molecular Mechanism. Cells 2020; 9:cells9040887. [PMID: 32260410 PMCID: PMC7226842 DOI: 10.3390/cells9040887] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023] Open
Abstract
Microautophagy is a type of autophagy. It is characterized by direct enclosing with the vacuolar/lysosomal membrane, which completes the isolation and uptake of cell components in the vacuole. Several publications present evidence that plants exhibit microautophagy. Plant microautophagy is involved in anthocyanin accumulation in the vacuole, eliminating damaged chloroplasts and degrading cellular components during starvation. However, information on the molecular mechanism of microautophagy is less available than that on the general macroautophagy, because the research focusing on microautophagy has not been widely reported. In yeast and animals, it is suggested that microautophagy can be classified into several types depending on morphology and the requirements of autophagy-related (ATG) genes. This review summarizes the studies on plant microautophagy and discusses possible techniques for a future study in this field while taking into account the information on microautophagy obtained from yeast and animals.
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35
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Chino H, Mizushima N. ER-Phagy: Quality Control and Turnover of Endoplasmic Reticulum. Trends Cell Biol 2020; 30:384-98. [PMID: 32302550 DOI: 10.1016/j.tcb.2020.02.001] [Citation(s) in RCA: 143] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/30/2020] [Accepted: 02/03/2020] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is the largest organelle in cells and has fundamental functions, such as folding, processing, and trafficking of proteins, cellular metabolism, and ion storage. To maintain its function, it is turned over constitutively, and even more actively under certain stress conditions. Quality control of the ER is mediated primarily by two pathways: the ubiquitin-proteasome system and autophagy (termed 'ER-phagy'). The identification of ER-phagy adaptor molecules has shed light on the mechanisms and physiological significance of ER-phagy. Here, we describe recent findings on various types of ER-phagy and present unanswered questions related to their mechanism and regulation.
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36
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Abstract
Nucleophagy, the mechanism for autophagic degradation of nuclear material, occurs in both a macro- and micronucleophagic manner. Upon nitrogen deprivation, we observed, in an in-depth fluorescence microscopy study, the formation of micronuclei: small parts of superfluous nuclear components surrounded by perinuclear ER. We identified two types of micronuclei associated with a corresponding autophagic mode. Our results showed that macronucleophagy degraded these smaller micronuclei. Engulfed in Atg8-positive phagophores and containing cargo receptor Atg39, macronucleophagic structures revealed finger-like extensions when observed in 3-dimensional reconstitutions of fluorescence microscopy images, suggesting directional growth. Interestingly, in the late stages of phagophore elongation, the adjacent vacuolar membrane showed a reduction of integral membrane protein Pho8. This change in membrane composition could indicate the formation of a specialized vacuolar domain, required for autophagosomal fusion. Significantly larger micronuclei formed at nucleus vacuole junctions and were identified as a substrate of piecemeal microautophagy of the nucleus (PMN), by the presence of the integral membrane protein Nvj1. Micronuclei sequestered by vacuolar invaginations also contained Atg39. A detailed investigation revealed that both Atg39 and Atg8 accumulated between the vacuolar tips. These findings suggest a role for Atg39 in micronucleophagy. Indeed, following the degradation of Nvj1, an exclusive substrate of PMN, in immunoblots, we could confirm the essential role of Atg39 for PMN. Our study thus details the involvement of Atg8 in both macronucleophagy and PMN and identifies Atg39 as the general cargo receptor for nucleophagic processes.Abbreviations: DIC: Differential interference contrast, FWHM: Full width at half maximum, IQR: Interquartile range, MIPA: Micropexophagy-specific membrane apparatus, NLS: Nuclear localization signal, NVJ: Nucleus vacuole junction, PMN: Piecemeal microautophagy of the nucleus, pnER: Perinuclear ER.
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Affiliation(s)
- Florian B Otto
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Michael Thumm
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
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37
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Abstract
Changing conditions necessitate cellular adaptation, which frequently entails adjustment of organelle size and shape. The endoplasmic reticulum (ER) is an organelle of exceptional morphological plasticity. In budding yeast, ER stress triggers the de novo formation of ER subdomains called ER whorls. These whorls are selectively degraded by a poorly defined type of microautophagy. We recently showed that ESCRT proteins are essential for microautophagic uptake of ER whorls into lysosomes, likely by mediating the final scission of the lysosomal membrane. Furthermore, ER-selective microautophagy acts in parallel with ER-selective macroautophagy. The molecular machineries for these two types of autophagy are distinct and their contributions to ER turnover vary according to conditions, suggesting that they serve different functions. Our study provides evidence for a direct role of ESCRTs in microautophagy and extends our understanding of how autophagy promotes organelle homeostasis.
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Affiliation(s)
- Jasmin A Schäfer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Heidelberg, Germany
| | - Sebastian Schuck
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Heidelberg, Germany
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38
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Oshima M, Seki T, Kurauchi Y, Hisatsune A, Katsuki H. Reciprocal Regulation of Chaperone-Mediated Autophagy/ Microautophagy and Exosome Release. Biol Pharm Bull 2020; 42:1394-1401. [PMID: 31366874 DOI: 10.1248/bpb.b19-00316] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Autophagy-lysosome proteolysis is involved in protein quality control and classified into macroautophagy (MA), microautophagy (mA) and chaperone-mediated autophagy (CMA), by the routes of substrate delivery to lysosomes. Both autophagy-lysosome proteolysis and exosome release are strongly associated with membrane trafficking. In the present study, we investigated how chemical and small interfering RNA (siRNA)-mediated activation and inhibition of these autophagic pathways affect exosome release in AD293 cells. Activation of MA and mA by rapamycin and activation of CMA by mycophenolic acid significantly decreased exosome release. Although lysosomal inhibitors, NH4Cl and bafilomycin A1, significantly increased exosome release, a MA inhibitor, 3-methyladenine, did not affect. Exosome release was significantly increased by the siRNA-mediated knockdown of LAMP2A, which is crucial for CMA. Inversely, activity of CMA/mA was significantly increased by the prevention of exosome release, which was induced by siRNA-mediated knockdown of Rab27a. These findings indicate that CMA/mA and exosome release are reciprocally regulated. This regulation would be the molecular basis of extracellular release and propagation of misfolded proteins in various neurodegenerative diseases.
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Affiliation(s)
- Mutsumi Oshima
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University
| | - Takahiro Seki
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University
| | - Yuki Kurauchi
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University
| | - Akinori Hisatsune
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University.,Priority Organization for Innovation and Excellence, Kumamoto University.,Program for Leading Graduate Schools "HIGO (Health life science: Interdisciplinary and Glocal Oriented) Program," Kumamoto University
| | - Hiroshi Katsuki
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University
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39
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Schäfer JA, Schessner JP, Bircham PW, Tsuji T, Funaya C, Pajonk O, Schaeff K, Ruffini G, Papagiannidis D, Knop M, Fujimoto T, Schuck S. ESCRT machinery mediates selective microautophagy of endoplasmic reticulum in yeast. EMBO J 2019; 39:e102586. [PMID: 31802527 PMCID: PMC6960443 DOI: 10.15252/embj.2019102586] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 10/30/2019] [Accepted: 11/11/2019] [Indexed: 01/14/2023] Open
Abstract
ER‐phagy, the selective autophagy of endoplasmic reticulum (ER), safeguards organelle homeostasis by eliminating misfolded proteins and regulating ER size. ER‐phagy can occur by macroautophagic and microautophagic mechanisms. While dedicated machinery for macro‐ER‐phagy has been discovered, the molecules and mechanisms mediating micro‐ER‐phagy remain unknown. Here, we first show that micro‐ER‐phagy in yeast involves the conversion of stacked cisternal ER into multilamellar ER whorls during microautophagic uptake into lysosomes. Second, we identify the conserved Nem1‐Spo7 phosphatase complex and the ESCRT machinery as key components for micro‐ER‐phagy. Third, we demonstrate that macro‐ and micro‐ER‐phagy are parallel pathways with distinct molecular requirements. Finally, we provide evidence that the ESCRT machinery directly functions in scission of the lysosomal membrane to complete the microautophagic uptake of ER. These findings establish a framework for a mechanistic understanding of micro‐ER‐phagy and, thus, a comprehensive appreciation of the role of autophagy in ER homeostasis.
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Affiliation(s)
- Jasmin A Schäfer
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Julia P Schessner
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Peter W Bircham
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Takuma Tsuji
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Charlotta Funaya
- Electron Microscopy Core Facility, Heidelberg University, Heidelberg, Germany
| | - Oliver Pajonk
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Katharina Schaeff
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Giulia Ruffini
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Dimitrios Papagiannidis
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Michael Knop
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Toyoshi Fujimoto
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Sebastian Schuck
- DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
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40
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Goto-Yamada S, Oikawa K, Bizan J, Shigenobu S, Yamaguchi K, Mano S, Hayashi M, Ueda H, Hara-Nishimura I, Nishimura M, Yamada K. Sucrose Starvation Induces Microautophagy in Plant Root Cells. Front Plant Sci 2019; 10:1604. [PMID: 31850051 PMCID: PMC6901504 DOI: 10.3389/fpls.2019.01604] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/14/2019] [Indexed: 05/26/2023]
Abstract
Autophagy is an essential system for degrading and recycling cellular components for survival during starvation conditions. Under sucrose starvation, application of a papain protease inhibitor E-64d to the Arabidopsis root and tobacco BY-2 cells induced the accumulation of vesicles, labeled with a fluorescent membrane marker FM4-64. The E-64d-induced vesicle accumulation was reduced in the mutant defective in autophagy-related genes ATG2, ATG5, and ATG7, suggesting autophagy is involved in the formation of these vesicles. To clarify the formation of these vesicles in detail, we monitored time-dependent changes of tonoplast, and vesicle accumulation in sucrose-starved cells. We found that these vesicles were derived from the tonoplast and produced by microautophagic process. The tonoplast proteins were excluded from the vesicles, suggesting that the vesicles are generated from specific membrane domains. Concanamycin A treatment in GFP-ATG8a transgenic plants showed that not all FM4-64-labeled vesicles, which were derived from the tonoplast, contained the ATG8a-containing structure. These results suggest that ATG8a may not always be necessary for microautophagy.
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Affiliation(s)
- Shino Goto-Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Kazusato Oikawa
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, Japan
| | - Jakub Bizan
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Shuji Shigenobu
- NIBB Core Research Facilities, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Katsushi Yamaguchi
- NIBB Core Research Facilities, National Institute for Basic Biology, Okazaki, Japan
| | - Shoji Mano
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Makoto Hayashi
- Department of Bioscience, Nagahama Institute of Bioscience and Technology, Nagahama, Japan
| | - Haruko Ueda
- Faculty of Science and Engineering, Konan University, Kobe, Japan
| | | | - Mikio Nishimura
- Faculty of Science and Engineering, Konan University, Kobe, Japan
| | - Kenji Yamada
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
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41
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De Leonibus C, Cinque L, Settembre C. Emerging lysosomal pathways for quality control at the endoplasmic reticulum. FEBS Lett 2019; 593:2319-2329. [PMID: 31388984 DOI: 10.1002/1873-3468.13571] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 01/01/2023]
Abstract
Protein misfolding occurring in the endoplasmic reticulum (ER) might eventually lead to aggregation and cellular distress, and is a primary pathogenic mechanism in multiple human disorders. Mammals have developed evolutionary-conserved quality control mechanisms at the level of the ER. The best characterized is the ER-associated degradation (ERAD) pathway, through which misfolded proteins translocate from the ER to the cytosol and are subsequently proteasomally degraded. However, increasing evidence indicates that additional quality control mechanisms apply for misfolded ER clients that are not eligible for ERAD. This review focuses on the alternative, ERAD-independent, mechanisms of clearance of misfolded polypeptides from the ER. These processes, collectively referred to as ER-to-lysosome-associated degradation, involve ER-phagy, microautophagy or vesicular transport. The identification of the underlying molecular mechanisms is particularly important for developing new therapeutic approaches for human diseases associated with protein aggregate formation.
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Affiliation(s)
| | - Laura Cinque
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy.,Department of Medical and Translational Science, University of Naples "Federico II", Italy
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42
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Abstract
The endoplasmic reticulum (ER) network has central roles in metabolism and cellular organization. The ER undergoes dynamic alterations in morphology, molecular composition and functional specification. Remodelling of the network under fluctuating conditions enables the continual performance of ER functions and minimizes stress. Recent data have revealed that selective autophagy‐mediated degradation of ER fragments, or ER‐phagy, fundamentally contributes to this remodelling. This review provides a perspective on established views of selective autophagy, comparing these with emerging mechanisms of ER‐phagy and related processes. The text discusses the impact of ER‐phagy on the function of the ER‐ and the cell, both in normal physiology and when dysregulated within disease settings. Finally, unanswered questions regarding the mechanisms and significance of ER‐phagy are highlighted.
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Affiliation(s)
- Simon Wilkinson
- Edinburgh Cancer Research UK Centre, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, UK
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43
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Abstract
The evolutionarily conserved target of rapamycin complex 1 (TORC1) regulates cell growth in a homeostatic manner by tuning anabolic and catabolic processes in response to nutritional and hormonal cues. Interestingly, rather than being localized at the plasma membrane as perhaps expected for an integrator of extracellular signals, TORC1 mainly localizes at vacuolar (in yeast) and lysosomal (in more complex eukaryotes) membranes where it seems optimally placed to sense both the nutrient status within the cytoplasm and the vacuolar/lysosomal compartment. How TORC1 controls downstream targets that are distant from the vacuole/lysosome, is currently poorly understood. In this context, we recently identified and characterized 2 spatially and functionally distinct pools of TORC1 in the budding yeast Saccharomyces cerevisiae: one at the vacuole that promotes protein synthesis, and another one at endosomes that inhibits protein degradation. Thus, our findings highlight the presence of spatially separated pools of TORC1 that are commissioned with functionally specific tasks within cells. In addition, they pinpoint the existence of signaling endosomes in yeast, which raises numerous new questions that are warranted to direct future research in this area.
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Affiliation(s)
- Riko Hatakeyama
- a Department of Biology , University of Fribourg , Fribourg , Switzerland
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44
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Abstract
Autophagy delivers cytosolic components to lysosomes and the vacuole for degradation. This pathway prevents starvation through bulk degradation and recycling of cytoplasmic components, and maintains cellular homeostasis through selective elimination of damaged proteins and organelles. Autophagic delivery processes are categorized into three types: macroautophagy, microautophagy, and chaperone-mediated autophagy. During macroautophagy, nascent, double membrane-bound vesicles termed autophagosomes sequester a portion of cytoplasm and deliver it to the vacuole/lysosomes. Molecular genetic studies in budding yeasts have identified a set of AUTOPHAGY (ATG) genes required for autophagosome formation. Although microautophagy involves the direct lysosomal/vacuolar engulfment and incorporation of a target into the lumen rather than the formation of autophagosomes, the membrane dynamics and possible roles of ATGs during microautophagy are under investigation. Our recent study revealed an ATG-dependent microautophagy process in plants, during which chloroplasts damaged by high visible light (HL) are selectively eliminated. Here, we discuss the membrane dynamics of the plant microautophagy that enables the transport of whole chloroplasts into the vacuole.
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Affiliation(s)
- Sakuya Nakamura
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Masanori Izumi
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- Creative Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan
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45
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Omari S, Makareeva E, Roberts-Pilgrim A, Mirigian L, Jarnik M, Ott C, Lippincott-Schwartz J, Leikin S. Noncanonical autophagy at ER exit sites regulates procollagen turnover. Proc Natl Acad Sci U S A 2018; 115:E10099-108. [PMID: 30287488 DOI: 10.1073/pnas.1814552115] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Type I collagen, a major component of bone, skin, and other connective tissues, is synthesized in the endoplasmic reticulum (ER) and passes through the secretory pathway. Rerouting of its procollagen precursor to a degradative pathway is crucial for reducing intracellular buildup in pathologies caused by defects in procollagen folding and trafficking. Here, we identify an autophagy pathway initiated at ER exit sites (ERESs). Procollagen proteins following this pathway accumulate at ERESs modified with ubiquitin, LC3, p62, and other autophagy machinery. Modified ERESs carrying procollagen are then engulfed by lysosomes through a microautophagy-like mechanism, not involving conventional, double-membrane autophagosomes. Procollagen homeostasis thus involves a noncanonical mode of autophagy initiated at ERESs, which might also be important in degradation of other secretory proteins. Type I collagen is the main component of bone matrix and other connective tissues. Rerouting of its procollagen precursor to a degradative pathway is crucial for osteoblast survival in pathologies involving excessive intracellular buildup of procollagen that is improperly folded and/or trafficked. What cellular mechanisms underlie this rerouting remains unclear. To study these mechanisms, we employed live-cell imaging and correlative light and electron microscopy (CLEM) to examine procollagen trafficking both in wild-type mouse osteoblasts and osteoblasts expressing a bone pathology-causing mutant procollagen. We found that although most procollagen molecules successfully trafficked through the secretory pathway in these cells, a subpopulation did not. The latter molecules appeared in numerous dispersed puncta colocalizing with COPII subunits, autophagy markers and ubiquitin machinery, with more puncta seen in mutant procollagen-expressing cells. Blocking endoplasmic reticulum exit site (ERES) formation suppressed the number of these puncta, suggesting they formed after procollagen entry into ERESs. The punctate structures containing procollagen, COPII, and autophagic markers did not move toward the Golgi but instead were relatively immobile. They appeared to be quickly engulfed by nearby lysosomes through a bafilomycin-insensitive pathway. CLEM and fluorescence recovery after photobleaching experiments suggested engulfment occurred through a noncanonical form of autophagy resembling microautophagy of ERESs. Overall, our findings reveal that a subset of procollagen molecules is directed toward lysosomal degradation through an autophagic pathway originating at ERESs, providing a mechanism to remove excess procollagen from cells.
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46
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Albrecht LV, Ploper D, Tejeda-Muñoz N, De Robertis EM. Arginine methylation is required for canonical Wnt signaling and endolysosomal trafficking. Proc Natl Acad Sci U S A 2018; 115:E5317-25. [PMID: 29773710 DOI: 10.1073/pnas.1804091115] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Arginine methylation has emerged as a widespread and reversible protein modification with the potential to regulate a multitude of cellular processes, but its function is poorly understood. Endolysosomes play an important role in Wnt signaling, in which glycogen synthase kinase 3 (GSK3) becomes sequestered inside multivesicular bodies (MVBs) by the process known as microautophagy, causing the stabilization of many proteins. Up to 20% of cellular proteins contain three or more consecutive putative GSK3 sites, and of these 33% also contain methylarginine (meArg) modifications. Intriguingly, a cytoskeletal protein was previously known to have meArg modifications that enhanced subsequent phosphorylations by GSK3. Here, we report the unexpected finding that protein arginine methyltransferase 1 (PRMT1) is required for canonical Wnt signaling. Treatment of cultured cells for 5-30 min with Wnt3a induced a large increase in total endocytic vesicles which were also positive for asymmetric dimethylarginine modifications. Protease protection studies, both biochemical and in situ in cultured cells, showed that many meArg-modified cytosolic proteins became rapidly translocated into MVBs together with GSK3 and Lys48-polyubiquitinated proteins by ESCRT-driven microautophagy. In the case of the transcription factor Smad4, we showed that a unique arginine methylation site was required for GSK3 phosphorylation and Wnt regulation. The enzyme PRMT1 was found to be essential for Wnt-stimulated arginine methylation, GSK3 sequestration, and canonical Wnt signaling. The results reveal a cell biological role for PRMT1 arginine methylation at the crossroads of growth factor signaling, protein phosphorylation, membrane trafficking, cytosolic proteolysis, and Wnt-regulated microautophagy.
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47
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Oku M, Sakai Y. Three Distinct Types of Microautophagy Based on Membrane Dynamics and Molecular Machineries. Bioessays 2018; 40:e1800008. [PMID: 29708272 DOI: 10.1002/bies.201800008] [Citation(s) in RCA: 151] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/02/2018] [Indexed: 01/13/2023]
Abstract
Microautophagy is originally defined as lysosomal (vacuolar) membrane dynamics to directly enwrap and transport cytosolic components into the lumen of the lytic organelle. Molecular details of microautophagy had remained unknown until genetic studies in yeast identified a set of proteins required for the process. Subsequent studies with other experimental model organisms resulted in a series of discoveries that accompanied an expansion of the definition of microautophagy to also encompass endosomal membrane dynamics. These findings, however, still impose puzzling, non-integrated images as to the molecular mechanism of microautophagy. By reviewing recent studies on microautophagy in various experimental systems, we propose the classification of microautophagy into three types, as the basis for developing a comprehensive view of the process.
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Affiliation(s)
- Masahide Oku
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Yasuyoshi Sakai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan.,Research Unit for Physiological Chemistry, The Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, 606-8502, Japan
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48
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Galluzzi L, Baehrecke EH, Ballabio A, Boya P, Bravo-San Pedro JM, Cecconi F, Choi AM, Chu CT, Codogno P, Colombo MI, Cuervo AM, Debnath J, Deretic V, Dikic I, Eskelinen EL, Fimia GM, Fulda S, Gewirtz DA, Green DR, Hansen M, Harper JW, Jäättelä M, Johansen T, Juhasz G, Kimmelman AC, Kraft C, Ktistakis NT, Kumar S, Levine B, Lopez-Otin C, Madeo F, Martens S, Martinez J, Melendez A, Mizushima N, Münz C, Murphy LO, Penninger JM, Piacentini M, Reggiori F, Rubinsztein DC, Ryan KM, Santambrogio L, Scorrano L, Simon AK, Simon HU, Simonsen A, Tavernarakis N, Tooze SA, Yoshimori T, Yuan J, Yue Z, Zhong Q, Kroemer G. Molecular definitions of autophagy and related processes. EMBO J 2017; 36:1811-1836. [PMID: 28596378 PMCID: PMC5494474 DOI: 10.15252/embj.201796697] [Citation(s) in RCA: 1078] [Impact Index Per Article: 154.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 12/15/2022] Open
Abstract
Over the past two decades, the molecular machinery that underlies autophagic responses has been characterized with ever increasing precision in multiple model organisms. Moreover, it has become clear that autophagy and autophagy-related processes have profound implications for human pathophysiology. However, considerable confusion persists about the use of appropriate terms to indicate specific types of autophagy and some components of the autophagy machinery, which may have detrimental effects on the expansion of the field. Driven by the overt recognition of such a potential obstacle, a panel of leading experts in the field attempts here to define several autophagy-related terms based on specific biochemical features. The ultimate objective of this collaborative exchange is to formulate recommendations that facilitate the dissemination of knowledge within and outside the field of autophagy research.
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Affiliation(s)
- Lorenzo Galluzzi
- Department of Radiation Oncology, Weill Cornell Medical College, New York, NY, USA
- Université Paris Descartes/Paris V, Paris, France
| | - Eric H Baehrecke
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Medical Genetics, Department of Pediatrics, Federico II University, Naples, Italy
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Patricia Boya
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - José Manuel Bravo-San Pedro
- Université Paris Descartes/Paris V, Paris, France
- Université Pierre et Marie Curie/Paris VI, Paris, France
- Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France
- INSERM, U1138, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
| | - Francesco Cecconi
- Department of Biology, University of Tor Vergata, Rome, Italy
- Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
- Department of Pediatric Hematology and Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Augustine M Choi
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Charleen T Chu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Patrice Codogno
- Université Paris Descartes/Paris V, Paris, France
- Institut Necker-Enfants Malades (INEM), Paris, France
- INSERM, U1151, Paris, France
- CNRS, UMR8253, Paris, France
| | - Maria Isabel Colombo
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología (IHEM)-CONICET, Mendoza, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Ana Maria Cuervo
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jayanta Debnath
- Department of Pathology, University of California San Francisco, San Francisco, CA, USA
| | - Vojo Deretic
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Ivan Dikic
- Institute of Biochemistry II, School of Medicine, Goethe University Frankfurt, Frankfurt, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt Main, Germany
- Department of Immunology and Medical Genetics, University of Split School of Medicine, Split, Croatia
| | | | - Gian Maria Fimia
- National Institute for Infectious Diseases "L. Spallanzani" IRCCS, Rome, Italy
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Lecce, Italy
| | - Simone Fulda
- Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - David A Gewirtz
- Department of Pharmacology and Toxicology and Medicine, Virginia Commonwealth University, Richmond, VA, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Malene Hansen
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Marja Jäättelä
- Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Terje Johansen
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø - The Arctic University of Norway, Tromsø, Norway
| | - Gabor Juhasz
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest, Hungary
- Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Alec C Kimmelman
- Department of Radiation Oncology, Perlmutter Cancer Center, NYU Langone Medical Center, New York, NY, USA
| | - Claudine Kraft
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | | | - Sharad Kumar
- Centre for Cancer Biology, University of South Australia, Adelaide, SA, Australia
| | - Beth Levine
- Center for Autophagy Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute (HHMI), Dallas, TX, USA
| | - Carlos Lopez-Otin
- Department de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo, Spain
- Centro de Investigación en Red de Cáncer, Oviedo, Spain
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Sascha Martens
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Jennifer Martinez
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Alicia Melendez
- Department of Biology, Queens College, Queens, NY, USA
- Graduate Center, City University of New York, New York, NY, USA
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Christian Münz
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zurich, Switzerland
| | - Leon O Murphy
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Josef M Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Campus Vienna BioCentre, Vienna, Austria
| | - Mauro Piacentini
- Department of Biology, University of Tor Vergata, Rome, Italy
- National Institute for Infectious Diseases "L. Spallanzani" IRCCS, Rome, Italy
| | - Fulvio Reggiori
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Kevin M Ryan
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - Laura Santambrogio
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Luca Scorrano
- Department of Biology, University of Padova, Padova, Italy
- Venetian Institute of Molecular Medicine, Padova, Italy
| | - Anna Katharina Simon
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Hans-Uwe Simon
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece
| | - Sharon A Tooze
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences Osaka University, Osaka, Japan
| | - Junying Yuan
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Ludwig Cancer Center, Harvard Medical School, Boston, MA, USA
| | - Zhenyu Yue
- Department of Neurology, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Qing Zhong
- Center for Autophagy Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Guido Kroemer
- Université Paris Descartes/Paris V, Paris, France
- Université Pierre et Marie Curie/Paris VI, Paris, France
- Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, Paris, France
- INSERM, U1138, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
- Department of Women's and Children's Health, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
- Pôle de Biologie, Hopitâl Européen George Pompidou, AP-HP, Paris, France
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49
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Tsuji T, Fujimoto M, Tatematsu T, Cheng J, Orii M, Takatori S, Fujimoto T. Niemann-Pick type C proteins promote microautophagy by expanding raft-like membrane domains in the yeast vacuole. eLife 2017; 6:e25960. [PMID: 28590904 PMCID: PMC5462540 DOI: 10.7554/elife.25960] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/16/2017] [Indexed: 11/13/2022] Open
Abstract
Niemann-Pick type C is a storage disease caused by dysfunction of NPC proteins, which transport cholesterol from the lumen of lysosomes to the limiting membrane of that compartment. Using freeze fracture electron microscopy, we show here that the yeast NPC orthologs, Ncr1p and Npc2p, are essential for formation and expansion of raft-like domains in the vacuolar (lysosome) membrane, both in stationary phase and in acute nitrogen starvation. Moreover, the expanded raft-like domains engulf lipid droplets by a microautophagic mechanism. We also found that the multivesicular body pathway plays a crucial role in microautophagy in acute nitrogen starvation by delivering sterol to the vacuole. These data show that NPC proteins promote microautophagy in stationary phase and under nitrogen starvation conditions, likely by increasing sterol in the limiting membrane of the vacuole.
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Affiliation(s)
- Takuma Tsuji
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Megumi Fujimoto
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tsuyako Tatematsu
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Jinglei Cheng
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Minami Orii
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Sho Takatori
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toyoshi Fujimoto
- Department of Molecular Cell Biology and Anatomy, Nagoya University Graduate School of Medicine, Nagoya, Japan
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50
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Seo AY, Lau PW, Feliciano D, Sengupta P, Gros MAL, Cinquin B, Larabell CA, Lippincott-Schwartz J. AMPK and vacuole-associated Atg14p orchestrate μ-lipophagy for energy production and long-term survival under glucose starvation. eLife 2017; 6. [PMID: 28394250 PMCID: PMC5407857 DOI: 10.7554/elife.21690] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 04/09/2017] [Indexed: 12/22/2022] Open
Abstract
Dietary restriction increases the longevity of many organisms, but the cell signaling and organellar mechanisms underlying this capability are unclear. We demonstrate that to permit long-term survival in response to sudden glucose depletion, yeast cells activate lipid-droplet (LD) consumption through micro-lipophagy (µ-lipophagy), in which fat is metabolized as an alternative energy source. AMP-activated protein kinase (AMPK) activation triggered this pathway, which required Atg14p. More gradual glucose starvation, amino acid deprivation or rapamycin did not trigger µ-lipophagy and failed to provide the needed substitute energy source for long-term survival. During acute glucose restriction, activated AMPK was stabilized from degradation and interacted with Atg14p. This prompted Atg14p redistribution from ER exit sites onto liquid-ordered vacuole membrane domains, initiating µ-lipophagy. Our findings that activated AMPK and Atg14p are required to orchestrate µ-lipophagy for energy production in starved cells is relevant for studies on aging and evolutionary survival strategies of different organisms. DOI:http://dx.doi.org/10.7554/eLife.21690.001
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Affiliation(s)
- Arnold Y Seo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Pick-Wei Lau
- Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Daniel Feliciano
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Prabuddha Sengupta
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Mark A Le Gros
- Department of Anatomy, University of California, San Francisco, San Francisco, United States.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Bertrand Cinquin
- Department of Anatomy, University of California, San Francisco, San Francisco, United States
| | - Carolyn A Larabell
- Department of Anatomy, University of California, San Francisco, San Francisco, United States.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Jennifer Lippincott-Schwartz
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
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