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Wang Y, Song Y, Xu L, Zhou W, Wang W, Jin Q, Xie Y, Zhang J, Liu J, Wu W, Li H, Liang L, Wang J, Yang Y, Chen X, Ge S, Gao T, Zhang L, Xie M. A Membrane-Targeting Aggregation-Induced Emission Probe for Monitoring Lipid Droplet Dynamics in Ischemia/Reperfusion-Induced Cardiomyocyte Ferroptosis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2309907. [PMID: 38696589 DOI: 10.1002/advs.202309907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 04/01/2024] [Indexed: 05/04/2024]
Abstract
Myocardial ischemia/reperfusion injury (MIRI) is the leading cause of irreversible myocardial damage. A pivotal pathogenic factor is ischemia/reperfusion (I/R)-induced cardiomyocyte ferroptosis, marked by iron overload and lipid peroxidation. However, the impact of lipid droplet (LD) changes on I/R-induced cardiomyocyte ferroptosis is unclear. In this study, an aggregation-induced emission probe, TPABTBP is developed that is used for imaging dynamic changes in LD during myocardial I/R-induced ferroptosis. TPABTBP exhibits excellent LD-specificity, superior capability for monitoring lipophagy, and remarkable photostability. Molecular dynamics (MD) simulation and super-resolution fluorescence imaging demonstrate that the TPABTBP is specifically localized to the phospholipid monolayer membrane of LDs. Imaging LDs in cardiomyocytes and myocardial tissue in model mice with MIRI reveals that the LD accumulation level increase in the early reperfusion stage (0-9 h) but decrease in the late reperfusion stage (>24 h) via lipophagy. The inhibition of LD breakdown significantly reduces the lipid peroxidation level in cardiomyocytes. Furthermore, it is demonstrated that chloroquine (CQ), an FDA-approved autophagy modulator, can inhibit ferroptosis, thereby attenuating MIRI in mice. This study describes the dynamic changes in LD during myocardial ischemia injury and suggests a potential therapeutic target for early MIRI intervention.
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Affiliation(s)
- Yihui Wang
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Yuan Song
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Lingling Xu
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Wuqi Zhou
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Wenyuan Wang
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Qiaofeng Jin
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Yuji Xie
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Junmin Zhang
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Jing Liu
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Wenqian Wu
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - He Li
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Le Liang
- The Institute of Advanced Studies Wuhan University, Wuhan, 430072, China
| | - Jing Wang
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Yali Yang
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Xiongwen Chen
- Department of Biopharmaceuticals & Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300052, China
- Department of Cardiology, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Shuping Ge
- Drexel University College of Medicine and St. Christopher's Hospital for Children, 3601 A Street, Philadelphia, PA, 19134, USA
| | - Tang Gao
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Li Zhang
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518029, China
| | - Mingxing Xie
- Department of Ultrasound Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Clinical Research Center for Medical Imaging, No. 1277 Jiefang Avenue, Wuhan, Hubei, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518029, China
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Kong Y, Guo P, Xu J, Li J, Wu M, Zhang Z, Wang Y, Liu X, Yang L, Liu M, Zhang H, Wang P, Zhang Z. MoMkk1 and MoAtg1 dichotomously regulating autophagy and pathogenicity through MoAtg9 phosphorylation in Magnaporthe oryzae. mBio 2024; 15:e0334423. [PMID: 38501872 PMCID: PMC11005334 DOI: 10.1128/mbio.03344-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/28/2024] [Indexed: 03/20/2024] Open
Abstract
Autophagy is a central biodegradation pathway critical in eliminating intracellular cargo to maintain cellular homeostasis and improve stress resistance. At the same time, the key component of the mitogen-activated protein kinase cascade regulating cell wall integrity signaling MoMkk1 has an essential role in the autophagy of the rice blast fungus Magnaporthe oryzae. Still, the mechanism of how MoMkk1 regulates autophagy is unclear. Interestingly, we found that MoMkk1 regulates the autophagy protein MoAtg9 through phosphorylation. MoAtg9 is a transmembrane protein subjected to phosphorylation by autophagy-related protein kinase MoAtg1. Here, we provide evidence demonstrating that MoMkk1-dependent MoAtg9 phosphorylation is required for phospholipid translocation during isolation membrane stages of autophagosome formation, an autophagic process essential for the development and pathogenicity of the fungus. In contrast, MoAtg1-dependent phosphorylation of MoAtg9 negatively regulates this process, also impacting growth and pathogenicity. Our studies are the first to demonstrate that MoAtg9 is subject to MoMkk1 regulation through protein phosphorylation and that MoMkk1 and MoAtg1 dichotomously regulate autophagy to underlie the growth and pathogenicity of M. oryzae.IMPORTANCEMagnaporthe oryzae utilizes multiple signaling pathways to promote colonization of host plants. MoMkk1, a cell wall integrity signaling kinase, plays an essential role in autophagy governed by a highly conserved autophagy kinase MoAtg1-mediated pathway. How MoMkk1 regulates autophagy in coordination with MoAtg1 remains elusive. Here, we provide evidence that MoMkk1 phosphorylates MoAtg9 to positively regulate phospholipid translocation during the isolation membrane or smaller membrane structures stage of autophagosome formation. This is in contrast to the negative regulation of MoAtg9 by MoAtg1 for the same process. Intriguingly, MoMkk1-mediated MoAtg9 phosphorylation enhances the fungal infection of rice, whereas MoAtg1-dependant MoAtg9 phosphorylation significantly attenuates it. Taken together, we revealed a novel mechanism of autophagy and virulence regulation by demonstrating the dichotomous functions of MoMkk1 and MoAtg1 in the regulation of fungal autophagy and pathogenicity.
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Affiliation(s)
- Yun Kong
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Pusheng Guo
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Jiayun Xu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Jiaxu Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Miao Wu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Ziqi Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Yifan Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Xinyu Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Leiyun Yang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Muxing Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Ping Wang
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
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3
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Ryan PJ, Uranga S, Stanelle ST, Lewis MH, O'Reilly CL, Cardin JM, Deaver JW, Morton AB, Fluckey JD. The autophagy inhibitor NSC185058 suppresses mTORC1-mediated protein anabolism in cultured skeletal muscle. Sci Rep 2024; 14:8094. [PMID: 38582781 PMCID: PMC10998866 DOI: 10.1038/s41598-024-58716-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 04/02/2024] [Indexed: 04/08/2024] Open
Abstract
The mammalian target of rapamycin (mTOR), and specifically the mTOR complex 1 (mTORC1) is the central regulator of anabolism in skeletal muscle. Among the many functions of this kinase complex is the inhibition of the catabolic process of autophagy; however, less work has been done in investigating the role of autophagy in regulating mTORC1 signaling. Using an in vitro model to better understand the pathways involved, we activated mTORC1 by several different means (growth factors, leucine supplementation, or muscle contraction), alone or with the autophagy inhibitor NSC185058. We found that inhibiting autophagy with NSC185058 suppresses mTORC1 activity, preventing any increase in cellular protein anabolism. These decrements were the direct result of action on the mTORC1 kinase, which we demonstrate, for the first time, cannot function when autophagy is inhibited by NSC185058. Our results indicate that, far from being a matter of unidirectional action, the relationship between mTORC1 and the autophagic cascade is more nuanced, with autophagy serving as an mTORC1 input, and mTORC1 inhibition of autophagy as a form of homeostatic feedback to regulate anabolic signaling. Future studies of cellular metabolism will have to consider this fundamental intertwining of protein anabolism and catabolism, and how it ultimately serves to regulate muscle proteostasis.
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Affiliation(s)
- Patrick J Ryan
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - Selina Uranga
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - Sean T Stanelle
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - Megan H Lewis
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - Colleen L O'Reilly
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - Jessica M Cardin
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - J William Deaver
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - Aaron B Morton
- Soft Tissue Regeneration and Applied Biomaterials Laboratory, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA
| | - James D Fluckey
- Muscle Biology Laboratory, Department of Kinesiology and Sport Management, Texas A&M University, Gilchrist Building, 2929 Research Parkway, College Station, TX, 77843-4243, USA.
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4
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Klute S, Sparrer KMJ. Friends and Foes: The Ambivalent Role of Autophagy in HIV-1 Infection. Viruses 2024; 16:500. [PMID: 38675843 PMCID: PMC11054699 DOI: 10.3390/v16040500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 03/19/2024] [Accepted: 03/21/2024] [Indexed: 04/28/2024] Open
Abstract
Autophagy has emerged as an integral part of the antiviral innate immune defenses, targeting viruses or their components for lysosomal degradation. Thus, successful viruses, like pandemic human immunodeficiency virus 1 (HIV-1), evolved strategies to counteract or even exploit autophagy for efficient replication. Here, we provide an overview of the intricate interplay between autophagy and HIV-1. We discuss the impact of autophagy on HIV-1 replication and report in detail how HIV-1 manipulates autophagy in infected cells and beyond. We also highlight tissue and cell-type specifics in the interplay between autophagy and HIV-1. In addition, we weigh exogenous modulation of autophagy as a putative double-edged sword against HIV-1 and discuss potential implications for future antiretroviral therapy and curative approaches. Taken together, we consider both antiviral and proviral roles of autophagy to illustrate the ambivalent role of autophagy in HIV-1 pathogenesis and therapy.
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5
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Ke PY. Molecular Mechanism of Autophagosome-Lysosome Fusion in Mammalian Cells. Cells 2024; 13:500. [PMID: 38534345 DOI: 10.3390/cells13060500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
In eukaryotes, targeting intracellular components for lysosomal degradation by autophagy represents a catabolic process that evolutionarily regulates cellular homeostasis. The successful completion of autophagy initiates the engulfment of cytoplasmic materials within double-membrane autophagosomes and subsequent delivery to autolysosomes for degradation by acidic proteases. The formation of autolysosomes relies on the precise fusion of autophagosomes with lysosomes. In recent decades, numerous studies have provided insights into the molecular regulation of autophagosome-lysosome fusion. In this review, an overview of the molecules that function in the fusion of autophagosomes with lysosomes is provided. Moreover, the molecular mechanism underlying how these functional molecules regulate autophagosome-lysosome fusion is summarized.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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6
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Yamamoto H, Matsui T. Molecular Mechanisms of Macroautophagy, Microautophagy, and Chaperone-Mediated Autophagy. J NIPPON MED SCH 2024; 91:2-9. [PMID: 37271546 DOI: 10.1272/jnms.jnms.2024_91-102] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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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7
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Botella J, Shaw CS, Bishop DJ. Autophagy and Exercise: Current Insights and Future Research Directions. Int J Sports Med 2024; 45:171-182. [PMID: 37582398 DOI: 10.1055/a-2153-9258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
Autophagy is a cellular process by which proteins and organelles are degraded inside the lysosome. Exercise is known to influence the regulation of autophagy in skeletal muscle. However, as gold standard techniques to assess autophagy flux in vivo are restricted to animal research, important gaps remain in our understanding of how exercise influences autophagy activity in humans. Using available datasets, we show how the gene expression profile of autophagy receptors and ATG8 family members differ between human and mouse skeletal muscle, providing a potential explanation for their differing exercise-induced autophagy responses. Furthermore, we provide a comprehensive view of autophagy regulation following exercise in humans by summarizing human transcriptomic and phosphoproteomic datasets that provide novel targets of potential relevance. These newly identified phosphorylation sites may provide an explanation as to why both endurance and resistance exercise lead to an exercise-induced reduction in LC3B-II, while possibly divergently regulating autophagy receptors, and, potentially, autophagy flux. We also provide recommendations to use ex vivo autophagy flux assays to better understand the influence of exercise, and other stimuli, on autophagy regulation in humans. This review provides a critical overview of the field and directs researchers towards novel research areas that will improve our understanding of autophagy regulation following exercise in humans.
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Affiliation(s)
- Javier Botella
- Metabolic Research Unit, School of Medicine and Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Waurn Ponds, Victoria, Australia
| | - Christopher S Shaw
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, 3216, VIC, Australia
| | - David J Bishop
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Australia
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8
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Mathiowetz AJ, Olzmann JA. Lipid droplets and cellular lipid flux. Nat Cell Biol 2024; 26:331-345. [PMID: 38454048 DOI: 10.1038/s41556-024-01364-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 01/24/2024] [Indexed: 03/09/2024]
Abstract
Lipid droplets are dynamic organelles that store neutral lipids, serve the metabolic needs of cells, and sequester lipids to prevent lipotoxicity and membrane damage. Here we review the current understanding of the mechanisms of lipid droplet biogenesis and turnover, the transfer of lipids and metabolites at membrane contact sites, and the role of lipid droplets in regulating fatty acid flux in lipotoxicity and cell death.
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Affiliation(s)
- Alyssa J Mathiowetz
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - James A Olzmann
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, USA.
- Chan Zuckerberg Biohub - San Francisco, San Francisco, CA, USA.
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9
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Wang Y, Hu Y, Xu R, Jin X, Jiao W. Plin2 inhibits autophagy via activating AKT/mTOR pathway in non-small cell lung cancer. Exp Cell Res 2024; 435:113955. [PMID: 38301990 DOI: 10.1016/j.yexcr.2024.113955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 01/13/2024] [Accepted: 01/25/2024] [Indexed: 02/03/2024]
Abstract
Perilipin 2 (Plin2) is known to be dysregulated in several human malignancies, which facilitates cancer progression. Recent studies have found that the abnormal expression of Plin2 is associated with poor prognosis of non-small cell lung cancer (NSCLC). However, the specific role of Plin2 and its underlying mechanism remain unclear. This study revealed that Plin2 expression was low in NSCLC tissues, and its relatively higher expression indicated larger tumor size and poorer prognosis. In vitro experiments proved that Plin2 promoted NSCLC cellular proliferation and inhibited autophagy by activating the AKT/mTOR pathway. Meanwhile, treatment with the AKT phosphorylation promoter or inhibitor neutralized the influence of Plin2 depletion or over-expression on proliferation and autophagy, respectively. In vivo study showed that Plin2 stimulated subcutaneous tumorigenesis of NSCLC cells in nude mice. Collectively, this study clarified the carcinogenic role of Plin2 and its molecular mechanism in NSCLC progression, which may facilitate a targeted therapy in the future.
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Affiliation(s)
- Yawei Wang
- Department of Thoracic Surgery, The Affiliated Hospital of Qingdao University, No.16 of Jiangsu Road, Qingdao, 266000, China
| | - Ye Hu
- Department of Nephrology, Qingdao Eighth People's Hospital, No.84 of Fengshan Road, Qingdao, 266121, China
| | - Rongjian Xu
- Department of Thoracic Surgery, The Affiliated Hospital of Qingdao University, No.16 of Jiangsu Road, Qingdao, 266000, China
| | - Xiangfeng Jin
- Department of Thoracic Surgery, The Affiliated Hospital of Qingdao University, No.16 of Jiangsu Road, Qingdao, 266000, China
| | - Wenjie Jiao
- Department of Thoracic Surgery, The Affiliated Hospital of Qingdao University, No.16 of Jiangsu Road, Qingdao, 266000, China.
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10
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van Vliet AR, Jefferies HBJ, Faull PA, Chadwick J, Ibrahim F, Skehel MJ, Tooze SA. Exploring the ATG9A interactome uncovers interaction with VPS13A. J Cell Sci 2024; 137:jcs261081. [PMID: 38294121 PMCID: PMC10911177 DOI: 10.1242/jcs.261081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 01/17/2024] [Indexed: 02/01/2024] Open
Abstract
ATG9A, a transmembrane protein of the core autophagy pathway, cycles between the Golgi, endosomes and a vesicular compartment. ATG9A was recently shown to act as a lipid scramblase, and this function is thought to require its interaction with another core autophagy protein, ATG2A, which acts as a lipid transfer protein. Together, ATG9A and ATG2A are proposed to function to expand the growing autophagosome. However, ATG9A is implicated in other pathways including membrane repair and lipid droplet homeostasis. To elucidate other ATG9A interactors within the autophagy pathway, or interactors beyond autophagy, we performed an interactome analysis through mass spectrometry. This analysis revealed a host of proteins involved in lipid synthesis and trafficking, including ACSL3, VPS13A and VPS13C. Furthermore, we show that ATG9A directly interacts with VPS13A and forms a complex that is distinct from the ATG9A-ATG2A complex.
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Affiliation(s)
| | | | - Peter A. Faull
- Proteomics Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK
| | | | - Fairouz Ibrahim
- Proteomics Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Mark J. Skehel
- Proteomics Science Technology Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Sharon A. Tooze
- Molecular Cell Biology of Autophagy, The Francis Crick Institute, London NW1 1AT, UK
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11
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Holzer E, Martens S, Tulli S. The Role of ATG9 Vesicles in Autophagosome Biogenesis. J Mol Biol 2024:168489. [PMID: 38342428 DOI: 10.1016/j.jmb.2024.168489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/13/2024]
Abstract
Autophagy mediates the degradation and recycling of cellular material in the lysosomal system. Dysfunctional autophagy is associated with a plethora of diseases including uncontrolled infections, cancer and neurodegeneration. In macroautophagy (hereafter autophagy) this material is encapsulated in double membrane vesicles, the autophagosomes, which form upon induction of autophagy. The precursors to autophagosomes, referred to as phagophores, first appear as small flattened membrane cisternae, which gradually enclose the cargo material as they grow. The assembly of phagophores during autophagy initiation has been a major subject of investigation over the past decades. A special focus has been ATG9, the only conserved transmembrane protein among the core machinery. The majority of ATG9 localizes to small Golgi-derived vesicles. Here we review the recent advances and breakthroughs regarding our understanding of how ATG9 and the vesicles it resides in serve to assemble the autophagy machinery and to establish membrane contact sites for autophagosome biogenesis. We also highlight open questions in the field that need to be addressed in the years to come.
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Affiliation(s)
- Elisabeth Holzer
- Max Perutz Labs, Vienna BioCenter Campus (VBC), Vienna, Austria; University of Vienna, Max Perutz Labs, Department of Biochemistry and Cell Biology, Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Campus-Vienna-Biocenter 1, Vienna, Austria.
| | - Sascha Martens
- Max Perutz Labs, Vienna BioCenter Campus (VBC), Vienna, Austria; University of Vienna, Max Perutz Labs, Department of Biochemistry and Cell Biology, Vienna, Austria.
| | - Susanna Tulli
- Max Perutz Labs, Vienna BioCenter Campus (VBC), Vienna, Austria; University of Vienna, Max Perutz Labs, Department of Biochemistry and Cell Biology, Vienna, Austria.
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12
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Milani SZ, Rezabakhsh A, Karimipour M, Salimi L, Mardi N, Narmi MT, Sadeghsoltani F, Valioglu F, Rahbarghazi R. Role of autophagy in angiogenic potential of vascular pericytes. Front Cell Dev Biol 2024; 12:1347857. [PMID: 38380339 PMCID: PMC10877016 DOI: 10.3389/fcell.2024.1347857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/24/2024] [Indexed: 02/22/2024] Open
Abstract
The vasculature system is composed of a multiplicity of juxtaposed cells to generate a functional biological barrier between the blood and tissues. On the luminal surface of blood vessels, endothelial cells (ECs) are in close contact with circulating cells while supporting basal lamina and pericytes wrap the abluminal surface. Thus, the reciprocal interaction of pericytes with ECs is a vital element in the physiological activity of the vascular system. Several reports have indicated that the occurrence of pericyte dysfunction under ischemic and degenerative conditions results in varied micro and macro-vascular complications. Emerging evidence points to the fact that autophagy, a conserved self-digestive cell machinery, can regulate the activity of several cells like pericytes in response to various stresses and pathological conditions. Here, we aim to highlight the role of autophagic response in pericyte activity and angiogenesis potential following different pathological conditions.
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Affiliation(s)
- Soheil Zamen Milani
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Aysa Rezabakhsh
- Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Karimipour
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Leila Salimi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Narges Mardi
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | | | - Ferzane Valioglu
- Technology Development Zones Management CO., Sakarya University, Sakarya, Türkiye
| | - Reza Rahbarghazi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Applied Cellular Sciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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13
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Wit M, Belykh A, Sumara G. Protein kinase D (PKD) on the crossroad of lipid absorption, synthesis and utilization. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119653. [PMID: 38104800 DOI: 10.1016/j.bbamcr.2023.119653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 10/19/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023]
Abstract
Inappropriate lipid levels in the blood, as well as its content and composition in different organs, underlie multiple metabolic disorders including obesity, non-alcoholic fatty liver disease, type 2 diabetes, and atherosclerosis. Multiple processes contribute to the complex metabolism of triglycerides (TGs), fatty acids (FAs), and other lipid species. These consist of digestion and absorption of dietary lipids, de novo FAs synthesis (lipogenesis), uptake of TGs and FAs by peripheral tissues, TGs storage in the intracellular depots as well as lipid utilization for β-oxidation and their conversion to lipid-derivatives. A majority of the enzymatic reactions linked to lipogenesis, TGs synthesis, lipid absorption, and transport are happening at the endoplasmic reticulum, while β-oxidation takes place in mitochondria and peroxisomes. The Golgi apparatus is a central sorting, protein- and lipid-modifying organelle and hence is involved in lipid metabolism as well. However, the impact of the processes taking part in the Golgi apparatus are often overseen. The protein kinase D (PKD) family (composed of three members, PKD1, 2, and 3) is the master regulator of Golgi dynamics. PKDs are also a sensor of different lipid species in distinct cellular compartments. In this review, we discuss the roles of PKD family members in the regulation of lipid metabolism including the processes executed by PKDs at the Golgi apparatus. We also discuss the role of PKDs-dependent signaling in different cellular compartments and organs in the context of the development of metabolic disorders.
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Affiliation(s)
- Magdalena Wit
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warszawa, Poland
| | - Andrei Belykh
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warszawa, Poland
| | - Grzegorz Sumara
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warszawa, Poland.
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14
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Yuan Z, Cai K, Li J, Chen R, Zhang F, Tan X, Jiu Y, Chang H, Hu B, Zhang W, Ding B. ATG14 targets lipid droplets and acts as an autophagic receptor for syntaxin18-regulated lipid droplet turnover. Nat Commun 2024; 15:631. [PMID: 38245527 PMCID: PMC10799895 DOI: 10.1038/s41467-024-44978-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 01/09/2024] [Indexed: 01/22/2024] Open
Abstract
Lipid droplets (LDs) are dynamic lipid storage organelles that can be degraded by autophagy machinery to release neutral lipids, a process called lipophagy. However, specific receptors and regulation mechanisms for lipophagy remain largely unknown. Here, we identify that ATG14, the core unit of the PI3KC3-C1 complex, also targets LD and acts as an autophagic receptor that facilitates LD degradation. A negative regulator, Syntaxin18 (STX18) binds ATG14, disrupting the ATG14-ATG8 family members interactions and subverting the PI3KC3-C1 complex formation. Knockdown of STX18 activates lipophagy dependent on ATG14 not only as the core unit of PI3KC3-C1 complex but also as the autophagic receptor, resulting in the degradation of LD-associated anti-viral protein Viperin. Furthermore, coronavirus M protein binds STX18 and subverts the STX18-ATG14 interaction to induce lipophagy and degrade Viperin, facilitating virus production. Altogether, our data provide a previously undescribed mechanism for additional roles of ATG14 in lipid metabolism and virus production.
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Affiliation(s)
- Zhen Yuan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Kun Cai
- Institute of Health Inspection and Testing, Hubei Provincial Center for Disease Control and Prevention, Wuhan, Hubei, 430079, China
| | - Jiajia Li
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Ruifeng Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Fuhai Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Xuan Tan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Yaming Jiu
- Unit of Cell Biology and Imaging Study of Pathogen Host Interaction, The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Haishuang Chang
- Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Bing Hu
- Institute of Health Inspection and Testing, Hubei Provincial Center for Disease Control and Prevention, Wuhan, Hubei, 430079, China
| | - Weiyi Zhang
- Department of Applied Biology, College of Natural Resources and Life Science, Dong-A University, Busan, 49315, Republic of Korea
| | - Binbin Ding
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.
- Cell Architecture Research Institute, Huazhong University of Science and Technology, Wuhan, Hubei, China.
- Guangzhou National Laboratory; State Key Laboratory of Respiratory Disease, Guangzhou, Guangzhou, Guangdong, 510000, China.
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15
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Markham BN, Ramnarine C, Kim S, Grever WE, Soto-Beasley AI, Heckman M, Ren Y, Osborne AC, Bhagwate AV, Liu Y, Wang C, Kim J, Wszolek ZK, Ross OA, Springer W, Fiesel FC. miRNA family miR-29 inhibits PINK1-PRKN dependent mitophagy via ATG9A. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.576122. [PMID: 38293184 PMCID: PMC10827147 DOI: 10.1101/2024.01.17.576122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Loss-of-function mutations in the genes encoding PINK1 and PRKN result in early-onset Parkinson disease (EOPD). Together the encoded enzymes direct a neuroprotective pathway that ensures the elimination of damaged mitochondria via autophagy. We performed a genome-wide high content imaging miRNA screen for inhibitors of the PINK1-PRKN pathway and identified all three members of the miRNA family 29 (miR-29). Using RNAseq we identified target genes and found that siRNA against ATG9A phenocopied the effects of miR-29 and inhibited the initiation of PINK1-PRKN mitophagy. Furthermore, we discovered two rare, potentially deleterious, missense variants (p.R631W and p.S828L) in our EOPD cohort and tested them experimentally in cells. While expression of wild-type ATG9A was able to rescue the effects of miR-29a, the EOPD-associated variants behaved like loss-of-function mutations. Together, our study validates miR-29 and its target gene ATG9A as novel regulators of mitophagy initiation. It further serves as proof-of-concept of finding novel, potentially disease-causing EOPD-linked variants specifically in mitophagy regulating genes. The nomination of genetic variants and biological pathways is important for the stratification and treatment of patients that suffer from devastating diseases, such as EOPD.
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Affiliation(s)
- Briana N Markham
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Chloe Ramnarine
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Songeun Kim
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | | | - Michael Heckman
- Division of Clinical Trials and Biostatistics, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Yingxue Ren
- Department of Quantitative Health Science, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Andrew C Osborne
- Department of Quantitative Health Science, Mayo Clinic, Rochester, MN 55905, USA
| | - Aditya V Bhagwate
- Department of Quantitative Health Science, Mayo Clinic, Rochester, MN 55905, USA
| | - Yuanhang Liu
- Department of Quantitative Health Science, Mayo Clinic, Rochester, MN 55905, USA
| | - Chen Wang
- Department of Quantitative Health Science, Mayo Clinic, Rochester, MN 55905, USA
| | - Jungsu Kim
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Owen A Ross
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
- Neuroscience PhD Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | - Wolfdieter Springer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
- Neuroscience PhD Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | - Fabienne C Fiesel
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
- Neuroscience PhD Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
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16
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Martin KR, Celano SL, Sheldon RD, Jones RG, MacKeigan JP. Quantitative Analysis of Autophagy in Single Cells: Differential Response to Amino Acid and Glucose Starvation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.569679. [PMID: 38077042 PMCID: PMC10705537 DOI: 10.1101/2023.12.01.569679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Autophagy is a highly conserved, intracellular recycling process by which cytoplasmic contents are degraded in the lysosome. This process occurs at a low level constitutively; however, it is induced robustly in response to stressors, in particular, starvation of critical nutrients such as amino acids and glucose. That said, the relative contribution of these inputs is ambiguous and many starvation medias are poorly defined or devoid of multiple nutrients. Here, we sought to generate a quantitative catalog of autophagy across multiple stages and in single, living cells under normal growth conditions as well as in media starved specifically of amino acids or glucose. We found that autophagy is induced by starvation of amino acids, but not glucose, in U2OS cells, and that MTORC1-mediated ULK1 regulation and autophagy are tightly linked to amino acid levels. While autophagy is engaged immediately during amino acid starvation, a heightened response occurs during a period marked by transcriptional upregulation of autophagy genes during sustained starvation. Finally, we demonstrated that cells immediately return to their initial, low-autophagy state when nutrients are restored, highlighting the dynamic relationship between autophagy and environmental conditions. In addition to sharing our findings here, we provide our data as a high-quality resource for others interested in mathematical modeling or otherwise exploring autophagy in individual cells across a population.
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Affiliation(s)
- Katie R. Martin
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Stephanie L. Celano
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Ryan D. Sheldon
- Mass Spectrometry Core, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Russell G. Jones
- Department of Metabolism and Nutritional Programming, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Jeffrey P. MacKeigan
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
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17
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Lu W, Yang J, Hu M, Zhong K, Wang Y, Yang Y, Loor JJ, Yang G, Han L. Effects of choline deficiency and supplementation on lipid droplet accumulation in bovine primary liver cells in vitro. J Dairy Sci 2023; 106:9868-9878. [PMID: 37678795 DOI: 10.3168/jds.2023-23452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 07/03/2023] [Indexed: 09/09/2023]
Abstract
Rumen-protected choline (RPC) supplementation in the periparturient period has in some instances prevented and alleviated fatty liver disease in dairy cows. Mechanistically, however, it is unclear how choline prevents the accumulation of lipid droplets (LD) in liver cells. In this study, primary liver cells isolated from liver tissue obtained via puncture biopsy from 3 nonpregnant mid-lactation multiparous Holstein cows (∼160 d postpartum) were used. Analyses of LD via oil red O staining, protein abundance via Western blotting, and phospholipid content and composition measured by thin-layer chromatography and HPLC/mass spectrometry were performed in liver cells cultured in choline-deficient medium containing 150 μmol/L linoleic acid for 24 h. In a subsequent experiment, lipophagy was assessed in liver cells cultured with 30, 60, or 90 µmol/L choline-chloride. All data were analyzed statistically using SPSS 20.0 via t-tests or one-way ANOVA. Compared with liver cells cultured in Dulbecco's Modified Eagle Medium alone, choline deficiency increased the average diameter of LD (1.59 vs. 2.10 µm), decreased the proportion of small LD (<2 µm) from 75.3% to 56.6%, and increased the proportion of large LD (>4 µm) from 5.6% to 15.0%. In addition, the speed of LD fusion was enhanced by the absence of choline. Among phospholipid species, the phosphatidylcholine (PC) content of liver cells decreased by 34.5%. Seventeen species of PC (PC [18:2_22:6], PC [15:0_16:1], PC [14:0_20:4], and so on) and 6 species of lysophosphatidylcholine (LPC; LPC [15:0/0:0]), PC (22:2/0:0), LPC (20:2/0:0), and so on] were decreased, while PC (14:1_16:1) and LPC (0:0/20:1) were increased. Choline deficiency increased the triglyceride (TAG) content (0.57 vs. 0.39 μmol/mg) in liver cells and increased the protein abundance of sterol regulatory element binding protein 1, sterol regulatory element binding protein cleavage activation protein, and fatty acid synthase by 23.5%, 17%, and 36.1%, respectively. Upon re-supplementation with choline, the phenotype of LD (TAG content, size, proportion, and phospholipid profile) was reversed, and the ratio of autophagy marker LC3II/LC3I protein was significantly upregulated in a dose-dependent manner. Overall, at least in vitro in mid-lactation cows, these data demonstrated that PC synthesis is necessary for normal LD formation, and both rely on choline availability. According to the limitation of the source of liver cells used, further work should be conducted to ascertain that these effects are applicable to liver cells from postpartum cows, the physiological stage where the use of RPC has been implemented for the prevention and treatment of fatty liver.
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Affiliation(s)
- Wenyan Lu
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, P.R. China
| | - Jingna Yang
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, P.R. China
| | - Mingyue Hu
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, P.R. China
| | - Kai Zhong
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, P.R. China
| | - Yueying Wang
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, P.R. China
| | - Yanbin Yang
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, P.R. China
| | - Juan J Loor
- Department of Animal Science and Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801
| | - Guoyu Yang
- Key Laboratory of Animal Growth and Development of Henan Province, College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, P.R. China
| | - Liqiang Han
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, P.R. China.
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18
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Lee JS, Dittmar M, Miller J, Li M, Ayyanathan K, Ferretti M, Hulahan J, Whig K, Etwebi Z, Griesman T, Schultz DC, Cherry S. Evolutionary arms race between SARS-CoV-2 and interferon signaling via dynamic interaction with autophagy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566859. [PMID: 38014114 PMCID: PMC10680587 DOI: 10.1101/2023.11.13.566859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
SARS-CoV-2 emerged, and is evolving to efficiently infect humans worldwide. SARS-CoV-2 evades early innate recognition, interferon signaling activated only in bystander cells. This balance of innate activation and viral evasion has important consequences, but the pathways involved are incompletely understood. Here we find that autophagy genes regulate innate immune signaling, impacting the basal set point of interferons, and thus permissivity to infection. Mechanistically, autophagy genes negatively regulate MAVS, and this low basal level of MAVS is efficiently antagonized by SARS-CoV-2 ORF9b, blocking interferon activation in infected cells. However, upon loss of autophagy increased MAVS overcomes ORF9b-mediated antagonism suppressing infection. This has led to the evolution of SARS-CoV-2 variants to express higher levels of ORF9b, allowing SARS-CoV-2 to replicate under conditions of increased MAVS signaling. Altogether, we find a critical role of autophagy in the regulation of innate immunity and uncover an evolutionary trajectory of SARS-CoV-2 ORF9b to overcome host defenses.
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19
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Vale-Costa S, Etibor TA, Brás D, Sousa AL, Ferreira M, Martins GG, Mello VH, Amorim MJ. ATG9A regulates the dissociation of recycling endosomes from microtubules to form liquid influenza A virus inclusions. PLoS Biol 2023; 21:e3002290. [PMID: 37983294 PMCID: PMC10695400 DOI: 10.1371/journal.pbio.3002290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 12/04/2023] [Accepted: 10/13/2023] [Indexed: 11/22/2023] Open
Abstract
It is now established that many viruses that threaten public health establish condensates via phase transitions to complete their lifecycles, and knowledge on such processes may offer new strategies for antiviral therapy. In the case of influenza A virus (IAV), liquid condensates known as viral inclusions, concentrate the 8 distinct viral ribonucleoproteins (vRNPs) that form IAV genome and are viewed as sites dedicated to the assembly of the 8-partite genomic complex. Despite not being delimited by host membranes, IAV liquid inclusions accumulate host membranes inside as a result of vRNP binding to the recycling endocytic marker Rab11a, a driver of the biogenesis of these structures. We lack molecular understanding on how Rab11a-recycling endosomes condensate specifically near the endoplasmic reticulum (ER) exit sites upon IAV infection. We show here that liquid viral inclusions interact with the ER to fuse, divide, and slide. We uncover that, contrary to previous indications, the reported reduction in recycling endocytic activity is a regulated process rather than a competition for cellular resources involving a novel role for the host factor ATG9A. In infection, ATG9A mediates the removal of Rab11a-recycling endosomes carrying vRNPs from microtubules. We observe that the recycling endocytic usage of microtubules is rescued when ATG9A is depleted, which prevents condensation of Rab11a endosomes near the ER. The failure to produce viral inclusions accumulates vRNPs in the cytosol and reduces genome assembly and the release of infectious virions. We propose that the ER supports the dynamics of liquid IAV inclusions, with ATG9A facilitating their formation. This work advances our understanding on how epidemic and pandemic influenza genomes are formed. It also reveals the plasticity of recycling endosomes to undergo condensation in response to infection, disclosing new roles for ATG9A beyond its classical involvement in autophagy.
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Affiliation(s)
- Sílvia Vale-Costa
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Temitope Akhigbe Etibor
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Daniela Brás
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Ana Laura Sousa
- Electron Microscopy Facility (EMF), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Mariana Ferreira
- Advanced Imaging Facility (AIF), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Gabriel G. Martins
- Advanced Imaging Facility (AIF), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Victor Hugo Mello
- Living Physics, Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
| | - Maria João Amorim
- Cell Biology of Viral Infection Lab (CBV), Instituto Gulbenkian de Ciência (IGC)—Fundação Calouste Gulbenkian, Oeiras, Portugal
- Cell Biology of Viral Infection Lab (CBV), Católica Biomedical Research Centre (CBR), Católica Medical School—Universidade Católica Portuguesa, Lisboa, Portugal
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20
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Hanna M, Guillén-Samander A, De Camilli P. RBG Motif Bridge-Like Lipid Transport Proteins: Structure, Functions, and Open Questions. Annu Rev Cell Dev Biol 2023; 39:409-434. [PMID: 37406299 DOI: 10.1146/annurev-cellbio-120420-014634] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
The life of eukaryotic cells requires the transport of lipids between membranes, which are separated by the aqueous environment of the cytosol. Vesicle-mediated traffic along the secretory and endocytic pathways and lipid transfer proteins (LTPs) cooperate in this transport. Until recently, known LTPs were shown to carry one or a few lipids at a time and were thought to mediate transport by shuttle-like mechanisms. Over the last few years, a new family of LTPs has been discovered that is defined by a repeating β-groove (RBG) rod-like structure with a hydrophobic channel running along their entire length. This structure and the localization of these proteins at membrane contact sites suggest a bridge-like mechanism of lipid transport. Mutations in some of these proteins result in neurodegenerative and developmental disorders. Here we review the known properties and well-established or putative physiological roles of these proteins, and we highlight the many questions that remain open about their functions.
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Affiliation(s)
- Michael Hanna
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andrés Guillén-Samander
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
- Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, Maryland, USA
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21
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Ran H, Sun W, Wang L, Wang X, Yu H, Chen J, Liu F, Chao Z, Pu Q, Liu Y, Zeng Y, Li Z, Wan Y, Yuan J. Proteomics coupled transcriptomics reveals lipopolysaccharide inhibiting peroxisome proliferator-activated receptors signalling pathway to reduce lipid droplets accumulation in mouse liver. Proteomics 2023; 23:e2300043. [PMID: 37269196 DOI: 10.1002/pmic.202300043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 05/04/2023] [Accepted: 05/22/2023] [Indexed: 06/04/2023]
Abstract
Lipid droplets (LDs) are multifunctional organelles consisting of a central compartment of non-polar lipids shielded from the cytoplasm by a phospholipid monolayer. The excessive accumulation of LDs in cells is closely related to the development and progression of many diseases in humans and animals, such as liver-related and cardiovascular diseases. Thus, regulating the LDs size and abundance is necessary to maintain metabolic homeostasis. This study found that lipopolysaccharide (LPS) stimulation reduced the LDs content in the mouse liver. We tried to explain the possible molecular mechanisms at the broad protein and mRNA levels, finding that inhibition of the peroxisome proliferator-activated receptors (PPAR) signalling pathway by LPS may be a critical factor in reducing LDs content.
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Affiliation(s)
- Haiying Ran
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Wei Sun
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Liting Wang
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Xiaoyang Wang
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Haili Yu
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Jiajia Chen
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Fang Liu
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Zhiyin Chao
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Qi Pu
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Yang Liu
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Youlong Zeng
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Zhangfu Li
- Hepato-Pancreato-Biliary Surgery, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Guangdong Province, China
| | - Ying Wan
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Jiangbei Yuan
- Hepato-Pancreato-Biliary Surgery, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Guangdong Province, China
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22
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Suzuki M, Funakoshi T, Kumagai K, Komatsu M, Waguri S. ATG9A supports Chlamydia trachomatis infection via autophagy-independent mechanisms. Microbiol Spectr 2023; 11:e0277423. [PMID: 37707289 PMCID: PMC10580829 DOI: 10.1128/spectrum.02774-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 07/18/2023] [Indexed: 09/15/2023] Open
Abstract
Chlamydia trachomatis infection can be regulated by autophagy-related (ATG) genes. Here, we found that the depletion of ATG9A, one of the core ATG genes, in HeLa cells suppressed C. trachomatis growth in the inclusion. The growth was restored by re-expressing ATG9A or an ATG9A mutant impairing lipid scramblase activity in ATG9A-knockout (KO) cells. Moreover, the depletion of lipid transfer proteins ATG2A/B, responsible for isolation membrane expansion together with ATG9A, did not significantly alter the growth, suggesting that the non-autophagic function of ATG9A supports C. trachomatis infection. ATG9A-KO cells showed no infection-induced redistribution of the Golgi from the perinuclear region to inclusion, which was restored by re-expressing the mutant but not the ATG9A mutant lacking an N-terminal adapter protein-binding domain. Re-expression of the N-terminal deletion mutant in ATG9A-KO cells did not rescue C. trachomatis growth, suggesting the importance of this domain for its growth. Although ATG9A-KO cells showed enhanced TBK1 activation, interferon (IFN)-β was not significantly increased, excluding the possibility that upregulation of stimulator of IFN genes (STING) signaling suppressed bacterial growth. Taken together, these findings suggest that the proper trafficking, rather than the isolation membrane expansion function, of ATG9A assists C. trachomatis growth in the inclusion. IMPORTANCE ATG9A is an autophagy-related gene that functions during the isolation membrane expansion process to form autophagosomes, but it also has other functions independent of autophagy. In this study, we employed ATG9A-deficient HeLa cells and found that the absence of ATG9A negatively impacted proliferation of Chlamydia trachomatis in inclusions. Furthermore, rescue experiments using ATG9A mutants revealed that this action was mediated not by its autophagic function but by its binding ability to clathrin adapter proteins. These findings suggest that the proper trafficking of ATG9A assists C. trachomatis growth in the inclusion.
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Affiliation(s)
- Michitaka Suzuki
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukushima, Japan
| | - Tomoko Funakoshi
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Keigo Kumagai
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan
| | - Masaaki Komatsu
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Satoshi Waguri
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukushima, Japan
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23
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Luo M, Law KC, He Y, Chung KK, Po MK, Feng L, Chung KP, Gao C, Zhuang X, Jiang L. Arabidopsis AUTOPHAGY-RELATED2 is essential for ATG18a and ATG9 trafficking during autophagosome closure. PLANT PHYSIOLOGY 2023; 193:304-321. [PMID: 37195145 DOI: 10.1093/plphys/kiad287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 05/18/2023]
Abstract
As a fundamental metabolic pathway, autophagy plays important roles in plant growth and development, particularly under stress conditions. A set of autophagy-related (ATG) proteins is recruited for the formation of a double-membrane autophagosome. Among them, the essential roles of ATG2, ATG18, and ATG9 have been well established in plant autophagy via genetic analysis; however, the underlying molecular mechanism for ATG2 in plant autophagosome formation remains poorly understood. In this study, we focused on the specific role of ATG2 in the trafficking of ATG18a and ATG9 during autophagy in Arabidopsis (Arabidopsis thaliana). Under normal conditions, YFP-ATG18a proteins are partially localized on late endosomes and translocated to ATG8e-labeled autophagosomes upon autophagic induction. Real-time imaging analysis revealed sequential recruitment of ATG18a on the phagophore membrane, showing that ATG18a specifically decorated the closing edges and finally disassociated from the completed autophagosome. However, in the absence of ATG2, most of the YFP-ATG18a proteins are arrested on autophagosomal membranes. Ultrastructural and 3D tomography analysis showed that unclosed autophagosome structures are accumulated in the atg2 mutant, displaying direct connections with the endoplasmic reticulum membrane and vesicular structures. Dynamic analysis of ATG9 vesicles suggested that ATG2 depletion also affects the association between ATG9 vesicles and the autophagosomal membrane. Furthermore, using interaction and recruitment analysis, we mapped the interaction relationship between ATG2 and ATG18a, implying a possible role of ATG18a in recruiting ATG2 and ATG9 to the membrane. Our findings unveil a specific role of ATG2 in coordinating ATG18a and ATG9 trafficking to mediate autophagosome closure in Arabidopsis.
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Affiliation(s)
- Mengqian Luo
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kai Ching Law
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yilin He
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Kit Chung
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Muk Kuen Po
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Lanlan Feng
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kin Pan Chung
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiaohong Zhuang
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Liwen Jiang
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
- CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
- Institute of Plant Molecular Biology and Agricultural Biotechnology, The Chinese University of Hong Kong, Hong Kong, China
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24
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Korfhage JL, Wan N, Elhan H, Kauffman L, Pineda M, Fuller DM, Thiam AR, Reinisch KM, Melia TJ. ATG2A-mediated bridge-like lipid transport regulates lipid droplet accumulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553257. [PMID: 37645754 PMCID: PMC10461963 DOI: 10.1101/2023.08.14.553257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
ATG2 proteins facilitate bulk lipid transport between membranes. ATG2 is an essential autophagy protein, but ATG2 also localizes to lipid droplets (LDs), and genetic depletion of ATG2 increases LD numbers while impairing fatty acid transport from LDs to mitochondria. How ATG2 supports LD homeostasis and whether lipid transport regulates this homeostasis remains unknown. Here we demonstrate that ATG2 is preferentially recruited to phospholipid monolayers such as those surrounding LDs rather than to phospholipid bilayers. In vitro, ATG2 can drive phospholipid transport from artificial LDs with rates that correlate with the binding affinities, such that phospholipids are moved much more efficiently when one of the ATG2-interacting structures is an artificial LD. ATG2 is thought to exhibit 'bridge-like" lipid transport, with lipids flowing across the protein between membranes. We mutated key amino acids within the bridge to form a transport-dead ATG2 mutant (TD-ATG2A) which we show specifically blocks bridge-like, but not shuttle-like, lipid transport in vitro. TD-ATG2A still localizes to LDs, but is unable to rescue LD accumulation in ATG2 knockout cells. Thus, ATG2 has a natural affinity for, and an enhanced activity upon LD surfaces and uses bridge-like lipid transport to support LD dynamics in cells.
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Affiliation(s)
- Justin L. Korfhage
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Neng Wan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Helin Elhan
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - Lisa Kauffman
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - Mia Pineda
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Devin M. Fuller
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Thomas J. Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
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25
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Melia TJ. Growing thin - How bulk lipid transport drives expansion of the autophagosome membrane but not of its lumen. Curr Opin Cell Biol 2023; 83:102190. [PMID: 37385155 PMCID: PMC10528516 DOI: 10.1016/j.ceb.2023.102190] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/30/2023] [Accepted: 05/30/2023] [Indexed: 07/01/2023]
Abstract
The key event in macroautophagy is the de novo formation of a new organelle called the autophagosome which when complete, will have captured bits of cytoplasm within its double-membrane structure. Eventual fusion with the lysosome allows this captured material to be degraded back to simple molecules which can be recycled to support cell function during starvation. How autophagosomes form has been a challenging question for over 60 years. This review highlights work that forms the basis for an autophagosome membrane expansion model grounded in protein-mediated lipid transport.
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26
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Lan ZQ, Ge ZY, Lv SK, Zhao B, Li CX. The regulatory role of lipophagy in central nervous system diseases. Cell Death Discov 2023; 9:229. [PMID: 37414782 DOI: 10.1038/s41420-023-01504-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/04/2023] [Accepted: 06/19/2023] [Indexed: 07/08/2023] Open
Abstract
Lipid droplets (LDs) are the organelles for storing neutral lipids, which are broken down when energy is insufficient. It has been suggested that excessive accumulation of LDs can affect cellular function, which is important to coordinate homeostasis of lipids in vivo. Lysosomes play an important role in the degradation of lipids, and the process of selective autophagy of LDs through lysosomes is known as lipophagy. Dysregulation of lipid metabolism has recently been associated with a variety of central nervous system (CNS) diseases, but the specific regulatory mechanisms of lipophagy in these diseases remain to be elucidated. This review summarizes various forms of lipophagy and discusses the role that lipophagy plays in the development of CNS diseases in order to reveal the related mechanisms and potential therapeutic targets for these diseases.
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Affiliation(s)
- Zhuo-Qing Lan
- Department of General practice medicine, the Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, P.R. China
| | - Zi-Yi Ge
- Department of Anesthesiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, P.R. China
| | - Shu-Kai Lv
- Department of General practice medicine, the Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, P.R. China
| | - Bing Zhao
- Department of Anesthesiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, P.R. China.
| | - Cai-Xia Li
- Department of General practice medicine, the Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, P.R. China.
- Department of Anesthesiology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, P.R. China.
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27
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Olivas TJ, Wu Y, Yu S, Luan L, Choi P, Guinn ED, Nag S, De Camilli PV, Gupta K, Melia TJ. ATG9 vesicles comprise the seed membrane of mammalian autophagosomes. J Cell Biol 2023; 222:e202208088. [PMID: 37115958 PMCID: PMC10148236 DOI: 10.1083/jcb.202208088] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 03/20/2023] [Accepted: 04/05/2023] [Indexed: 04/30/2023] Open
Abstract
As the autophagosome forms, its membrane surface area expands rapidly, while its volume is kept low. Protein-mediated transfer of lipids from another organelle to the autophagosome likely drives this expansion, but as these lipids are only introduced into the cytoplasmic-facing leaflet of the organelle, full membrane growth also requires lipid scramblase activity. ATG9 harbors scramblase activity and is essential to autophagosome formation; however, whether ATG9 is integrated into mammalian autophagosomes remains unclear. Here we show that in the absence of lipid transport, ATG9 vesicles are already competent to collect proteins found on mature autophagosomes, including LC3-II. Further, we use styrene-maleic acid lipid particles to reveal the nanoscale organization of protein on LC3-II membranes; ATG9 and LC3-II are each fully integrated into expanding autophagosomes. The ratios of these two proteins at different stages of maturation demonstrate that ATG9 proteins are not continuously integrated, but rather are present on the seed vesicles only and become diluted in the expanding autophagosome membrane.
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Affiliation(s)
- Taryn J. Olivas
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Yumei Wu
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
- Department of Neuroscience, School of Medicine, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, School of Medicine, Yale University, New Haven, CT, USA
- Program in Cellular Neuroscience Neurodegeneration and Repair, School of Medicine, Yale University, New Haven, CT, USA
| | - Shenliang Yu
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Lin Luan
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Peter Choi
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Emily D. Guinn
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Shanta Nag
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
| | - Pietro V. De Camilli
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
- Department of Neuroscience, School of Medicine, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, School of Medicine, Yale University, New Haven, CT, USA
- Program in Cellular Neuroscience Neurodegeneration and Repair, School of Medicine, Yale University, New Haven, CT, USA
| | - Kallol Gupta
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
| | - Thomas J. Melia
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT, USA
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28
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Tonkin-Reeves A, Giuliani CM, Price JT. Inhibition of autophagy; an opportunity for the treatment of cancer resistance. Front Cell Dev Biol 2023; 11:1177440. [PMID: 37363731 PMCID: PMC10290173 DOI: 10.3389/fcell.2023.1177440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/24/2023] [Indexed: 06/28/2023] Open
Abstract
The process of macroautophagy plays a pivotal role in the degradation of long-lived, superfluous, and damaged proteins and organelles, which are later recycled for cellular use. Normal cells rely on autophagy to combat various stressors and insults to ensure survival. However, autophagy is often upregulated in cancer cells, promoting a more aggressive phenotype that allows mutated cells to evade death after exposure to therapeutic treatments. As a result, autophagy has emerged as a significant factor in therapeutic resistance across many cancer types, with underlying mechanisms such as DNA damage, cell cycle arrest, and immune evasion. This review provides a comprehensive summary of the role of autophagy in therapeutic resistance and the limitations of available autophagic inhibitors in cancer treatment. It also highlights the urgent need to explore new inhibitors that can synergize with existing therapies to achieve better patient treatment outcomes. Advancing research in this field is crucial for developing more effective treatments that can help improve the lives of cancer patients.
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Affiliation(s)
- Asha Tonkin-Reeves
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Charlett M. Giuliani
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), Victoria University and Western Health, Melbourne, VIC, Australia
| | - John T. Price
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, VIC, Australia
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
- Australian Institute for Musculoskeletal Science (AIMSS), Victoria University and Western Health, Melbourne, VIC, Australia
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
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29
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Kirat D, Alahwany AM, Arisha AH, Abdelkhalek A, Miyasho T. Role of Macroautophagy in Mammalian Male Reproductive Physiology. Cells 2023; 12:cells12091322. [PMID: 37174722 PMCID: PMC10177121 DOI: 10.3390/cells12091322] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023] Open
Abstract
Physiologically, autophagy is an evolutionarily conserved and self-degradative process in cells. Autophagy carries out normal physiological roles throughout mammalian life. Accumulating evidence shows autophagy as a mechanism for cellular growth, development, differentiation, survival, and homeostasis. In male reproductive systems, normal spermatogenesis and steroidogenesis need a balance between degradation and energy supply to preserve cellular metabolic homeostasis. The main process of autophagy includes the formation and maturation of the phagophore, autophagosome, and autolysosome. Autophagy is controlled by a group of autophagy-related genes that form the core machinery of autophagy. Three types of autophagy mechanisms have been discovered in mammalian cells: macroautophagy, microautophagy, and chaperone-mediated autophagy. Autophagy is classified as non-selective or selective. Non-selective macroautophagy randomly engulfs the cytoplasmic components in autophagosomes that are degraded by lysosomal enzymes. While selective macroautophagy precisely identifies and degrades a specific element, current findings have shown the novel functional roles of autophagy in male reproduction. It has been recognized that dysfunction in the autophagy process can be associated with male infertility. Overall, this review provides an overview of the cellular and molecular basics of autophagy and summarizes the latest findings on the key role of autophagy in mammalian male reproductive physiology.
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Affiliation(s)
- Doaa Kirat
- Department of Physiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44519, Egypt
| | - Ahmed Mohamed Alahwany
- Department of Animal Physiology and Biochemistry, Faculty of Veterinary Medicine, Badr University in Cairo (BUC), Cairo, Badr City 11829, Egypt
| | - Ahmed Hamed Arisha
- Department of Physiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44519, Egypt
- Department of Animal Physiology and Biochemistry, Faculty of Veterinary Medicine, Badr University in Cairo (BUC), Cairo, Badr City 11829, Egypt
| | - Adel Abdelkhalek
- Faculty of Veterinary Medicine, Badr University in Cairo (BUC), Cairo, Badr City 11829, Egypt
| | - Taku Miyasho
- Laboratory of Animal Biological Responses, Department of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
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30
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He Y, Gao J, Luo M, Gao C, Lin Y, Wong HY, Cui Y, Zhuang X, Jiang L. VAMP724 and VAMP726 are involved in autophagosome formation in Arabidopsis thaliana. Autophagy 2023; 19:1406-1423. [PMID: 36130166 PMCID: PMC10240985 DOI: 10.1080/15548627.2022.2127240] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 11/02/2022] Open
Abstract
Macroautophagy/autophagy, an evolutionarily conserved degradative process essential for cell homeostasis and development in eukaryotes, involves autophagosome formation and fusion with a lysosome/vacuole. The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins play important roles in regulating autophagy in mammals and yeast, but relatively little is known about SNARE function in plant autophagy. Here we identified and characterized two Arabidopsis SNAREs, AT4G15780/VAMP724 and AT1G04760/VAMP726, involved in plant autophagy. Phenotypic analysis showed that mutants of VAMP724 and VAMP726 are sensitive to nutrient-starved conditions. Live-cell imaging on mutants of VAMP724 and VAMP726 expressing YFP-ATG8e showed the formation of abnormal autophagic structures outside the vacuoles and compromised autophagic flux. Further immunogold transmission electron microscopy and electron tomography (ET) analysis demonstrated a direct connection between the tubular autophagic structures and the endoplasmic reticulum (ER) in vamp724-1 vamp726-1 double mutants. Further transient co-expression, co-immunoprecipitation and double immunogold TEM analysis showed that ATG9 (autophagy related 9) interacts and colocalizes with VAMP724 and VAMP726 in ATG9-positive vesicles during autophagosome formation. Taken together, VAMP724 and VAMP726 regulate autophagosome formation likely working together with ATG9 in Arabidopsis.Abbreviations: ATG, autophagy related; BTH, benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester; Conc A, concanamycin A; EM, electron microscopy; ER, endoplasmic reticulum; FRET, Förster/fluorescence resonance energy transfer; MS, Murashige and Skoog; MVB, multivesicular body; PAS, phagophore assembly site; PM, plasma membrane; PVC, prevacuolar compartment; SNARE, soluble N-ethylmaleimide-sensitive factor attachment protein receptor; TEM, transmission electron microscopy; TGN, trans-Golgi network; WT, wild-type.
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Affiliation(s)
- Yilin He
- Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jiayang Gao
- Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Mengqian Luo
- Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Youshun Lin
- Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Hiu Yan Wong
- Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yong Cui
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Xiaohong Zhuang
- Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Liwen Jiang
- Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
- CUHK Shenzhen Research Institute, Shenzhen, China
- Institute of Plant Molecular Biology and Agricultural Biotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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Li H, Yu Z, Niu Z, Cheng Y, Wei Z, Cai Y, Ma F, Hu L, Zhu J, Zhang W. A neuroprotective role of Ufmylation through Atg9 in the aging brain of Drosophila. Cell Mol Life Sci 2023; 80:129. [PMID: 37086384 PMCID: PMC11073442 DOI: 10.1007/s00018-023-04778-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/09/2023] [Accepted: 04/11/2023] [Indexed: 04/23/2023]
Abstract
Ufmylation is a recently identified small ubiquitin-like modification, whose biological function and relevant cellular targets are poorly understood. Here we present evidence of a neuroprotective role for Ufmylation involving Autophagy-related gene 9 (Atg9) during Drosophila aging. The Ufm1 system ensures the health of aged neurons via Atg9 by coordinating autophagy and mTORC1, and maintaining mitochondrial homeostasis and JNK (c-Jun N-terminal kinase) activity. Neuron-specific expression of Atg9 suppresses the age-associated movement defect and lethality caused by loss of Ufmylation. Furthermore, Atg9 is identified as a conserved target of Ufm1 conjugation mediated by Ddrgk1, a critical regulator of Ufmylation. Mammalian Ddrgk1 was shown to be indispensable for the stability of endogenous Atg9A protein in mouse embryonic fibroblast (MEF) cells. Taken together, our findings might have important implications for neurodegenerative diseases in mammals.
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Affiliation(s)
- Huifang Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhenghong Yu
- Department of Rheumatology and Immunology, Jinling Hospital, Affiliated Hosptial of Medical School, Nanjing University, Nanjing, 210002, China
| | - Zikang Niu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yun Cheng
- Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, 210009, China
| | - Zhenhao Wei
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yafei Cai
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Fei Ma
- College of Life Science, Nanjing Normal University, Nanjing, 210023, China
| | - Lanxin Hu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiejie Zhu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wei Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.
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Guillén-Samander A, De Camilli P. Endoplasmic Reticulum Membrane Contact Sites, Lipid Transport, and Neurodegeneration. Cold Spring Harb Perspect Biol 2023; 15:a041257. [PMID: 36123033 PMCID: PMC10071438 DOI: 10.1101/cshperspect.a041257] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Endoplasmic Reticulum (ER) is an endomembrane system that plays a multiplicity of roles in cell physiology and populates even the most distal cell compartments, including dendritic tips and axon terminals of neurons. Some of its functions are achieved by a cross talk with other intracellular membranous organelles and with the plasma membrane at membrane contacts sites (MCSs). As the ER synthesizes most membrane lipids, lipid exchanges mediated by lipid transfer proteins at MCSs are a particularly important aspect of this cross talk, which synergizes with the cross talk mediated by vesicular transport. Several mutations of genes that encode proteins localized at ER MCSs result in familial neurodegenerative diseases, emphasizing the importance of the normal lipid traffic within cells for a healthy brain. Here, we provide an overview of such diseases, with a specific focus on proteins that directly or indirectly impact lipid transport.
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Affiliation(s)
- Andrés Guillén-Samander
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06520, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland 20815, USA
| | - Pietro De Camilli
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06520, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland 20815, USA
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Ke PY. Crosstalk between Autophagy and RLR Signaling. Cells 2023; 12:cells12060956. [PMID: 36980296 PMCID: PMC10047499 DOI: 10.3390/cells12060956] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Autophagy plays a homeostatic role in regulating cellular metabolism by degrading unwanted intracellular materials and acts as a host defense mechanism by eliminating infecting pathogens, such as viruses. Upon viral infection, host cells often activate retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling to induce the transcription of type I interferons, thus establishing the first line of the innate antiviral response. In recent years, numerous studies have shown that virus-mediated autophagy activation may benefit viral replication through different actions on host cellular processes, including the modulation of RLR-mediated innate immunity. Here, an overview of the functional molecules and regulatory mechanism of the RLR antiviral immune response as well as autophagy is presented. Moreover, a summary of the current knowledge on the biological role of autophagy in regulating RLR antiviral signaling is provided. The molecular mechanisms underlying the crosstalk between autophagy and RLR innate immunity are also discussed.
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Affiliation(s)
- Po-Yuan Ke
- Department of Biochemistry & Molecular Biology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Liver Research Center, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
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Naringin Alleviates Glucose-Induced Aging by Reducing Fat Accumulation and Promoting Autophagy in Caenorhabditis elegans. Nutrients 2023; 15:nu15040907. [PMID: 36839265 PMCID: PMC9961211 DOI: 10.3390/nu15040907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023] Open
Abstract
Naringin (Nar) is a dihydroflavonoid compound, widely found in citrus fruit and used in Chinese herbal medicine. As a phytochemical, it acts as a dietary supplement that can delay aging and prevent aging-related disease, such as obesity and diabetes. However, its exact mechanism remains unclear. In this study, the high-glucose-induced (HGI) Caenorhabditis elegans model was used to evaluate the anti-aging and anti-obesity effects of Nar. The mean lifespan and fast movement span of HGI worms were extended roughly 24% and 11%, respectively, by Nar treatment. Oil red O staining revealed a significant reduction in fat accumulation and dFP::LGG-labeled worms showed the promotion of autophagy. Additionally, whole transcriptome sequencing and gene set variation analysis suggested that Nar upregulated the lipid biosynthesis and metabolism pathways, as well as the TGF-β, Wnt and longevity signaling pathways. Protein-protein interaction (PPI) network analysis identified hub genes in these pathways for further analysis. Mutant worms and RNA interference were used to study mechanisms; the suppression of hlh-30, lgg-1, unc-51, pha-4, skn-1 and yap-1 disabled the fat-lowering, lifespan-prolonging, and health-promoting properties of Nar. Collectively, our findings indicate that Nar plays an important role in alleviating HGI-aging and anti-obesity effects by reducing fat accumulation and promoting autophagy.
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Autophagy/Mitophagy Regulated by Ubiquitination: A Promising Pathway in Cancer Therapeutics. Cancers (Basel) 2023; 15:cancers15041112. [PMID: 36831455 PMCID: PMC9954143 DOI: 10.3390/cancers15041112] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
Autophagy is essential for organismal development, maintenance of energy homeostasis, and quality control of organelles and proteins. As a selective form of autophagy, mitophagy is necessary for effectively eliminating dysfunctional mitochondria. Both autophagy and mitophagy are linked with tumor progression and inhibition. The regulation of mitophagy and autophagy depend upon tumor type and stage. In tumors, mitophagy has dual roles: it removes damaged mitochondria to maintain healthy mitochondria and energy production, which are necessary for tumor growth. In contrast, mitophagy has been shown to inhibit tumor growth by mitigating excessive ROS production, thus preventing mutation and chromosomal instability. Ubiquitination and deubiquitination are important modifications that regulate autophagy. Multiple E3 ubiquitin ligases and DUBs modulate the activity of the autophagy and mitophagy machinery, thereby influencing cancer progression. In this review, we summarize the mechanistic association between cancer development and autophagy/mitophagy activities regulated by the ubiquitin modification of autophagic proteins. In addition, we discuss the function of multiple proteins involved in autophagy/mitophagy in tumors that may represent potential therapeutic targets.
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Hu G, Hauk PJ, Zhang N, Elsegeiny W, Guardia CM, Kullas A, Crosby K, Deterding RR, Schedel M, Reynolds P, Abbott JK, Knight V, Pittaluga S, Raffeld M, Rosenzweig SD, Bonifacino JS, Uzel G, Williamson PR, Gelfand EW. Autophagy-associated immune dysregulation and hyperplasia in a patient with compound heterozygous mutations in ATG9A. Autophagy 2023; 19:678-691. [PMID: 35838483 PMCID: PMC9851204 DOI: 10.1080/15548627.2022.2093028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 01/27/2023] Open
Abstract
ABBREVIATIONS BCL2: BCL2 apoptosis regulator; BCL10: BCL10 immune signaling adaptor; CARD11: caspase recruitment domain family member 11; CBM: CARD11-BCL10-MALT1; CR2: complement C3d receptor 2; EBNA: Epstein Barr nuclear antigen; EBV: Epstein-Barr virus; FCGR3A; Fc gamma receptor IIIa; GLILD: granulomatous-lymphocytic interstitial lung disease; HV: healthy volunteer; IKBKB/IKB kinase: inhibitor of nuclear factor kappa B kinase subunit beta; IL2RA: interleukin 2 receptor subunit alpha; MALT1: MALT1 paracaspase; MS4A1: membrane spanning 4-domain A1; MTOR: mechanistic target of rapamycin kinase; MYC: MYC proto-oncogene, bHLH: transcription factor; NCAM1: neural cell adhesion molecule 1; NFKB: nuclear factor kappa B; NIAID: National Institute of Allergy and Infectious Diseases; NK: natural killer; PTPRC: protein tyrosine phosphatase receptor type C; SELL: selectin L; PBMCs: peripheral blood mononuclear cells; TR: T cell receptor; Tregs: regulatory T cells; WT: wild-type.
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Affiliation(s)
- Guowu Hu
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Pia J Hauk
- Divisions of Allergy and Immunology and Cell Biology and Immunodeficiency Diagnosis and Treatment Program, Department of Pediatrics, National Jewish Health, Denver, CO, USA
- Section Pediatric Allergy and Immunology, Children’s Hospital, Colorado, Aurora, CO, USA
| | - Nannan Zhang
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Waleed Elsegeiny
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carlos M. Guardia
- Section on Intracellular Protein Trafficking, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Amy Kullas
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kevin Crosby
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Robin R. Deterding
- Section Pediatric Pulmonary Medicine, Children’s Hospital, Colorado, Aurora, CO, USA
| | - Michaela Schedel
- Divisions of Allergy and Immunology and Cell Biology and Immunodeficiency Diagnosis and Treatment Program, Department of Pediatrics, National Jewish Health, Denver, CO, USA
- Department of Pulmonary Medicine, University Medicine Essen-Ruhrlandklinik, Essen, Germany
- Department of Pulmonary Medicine, University Medicine Essen, University Hospital, Essen, Germany
| | - Paul Reynolds
- Divisions of Allergy and Immunology and Cell Biology and Immunodeficiency Diagnosis and Treatment Program, Department of Pediatrics, National Jewish Health, Denver, CO, USA
| | - Jordan K Abbott
- Divisions of Allergy and Immunology and Cell Biology and Immunodeficiency Diagnosis and Treatment Program, Department of Pediatrics, National Jewish Health, Denver, CO, USA
- Section Pediatric Allergy and Immunology, Children’s Hospital, Colorado, Aurora, CO, USA
| | - Vijaya Knight
- Section Pediatric Allergy and Immunology, Children’s Hospital, Colorado, Aurora, CO, USA
| | - Stefania Pittaluga
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mark Raffeld
- Immunology Service, Department of Laboratory Medicine, NIH Clinical Center, Bethesda, MD, USA
| | - Sergio D. Rosenzweig
- Immunology Service, Department of Laboratory Medicine, NIH Clinical Center, Bethesda, MD, USA
| | - Juan S. Bonifacino
- Section on Intracellular Protein Trafficking, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Gulbu Uzel
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Peter R. Williamson
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Erwin W. Gelfand
- Divisions of Allergy and Immunology and Cell Biology and Immunodeficiency Diagnosis and Treatment Program, Department of Pediatrics, National Jewish Health, Denver, CO, USA
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Wang YN, Liu FJ, Liu HD, Zhang Y, Jiao X, Ye ML, Zhao ZBK, Zhang SF. Regulation of autophagy and lipid accumulation under phosphate limitation in Rhodotorula toruloides. Front Microbiol 2023; 13:1046114. [PMID: 36777022 PMCID: PMC9908577 DOI: 10.3389/fmicb.2022.1046114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/23/2022] [Indexed: 01/27/2023] Open
Abstract
Background It is known that autophagy is essential for cell survival under stress conditions. Inorganic phosphate (Pi) is an essential nutrient for cell growth and Pi-limitation can trigger autophagy and lipid accumulation in oleaginous yeasts, yet protein (de)-phosphorylation and related signaling events in response to Pi limitation and the molecular basis linking Pi-limitation to autophagy and lipid accumulation remain elusive. Results Here, we compared the proteome and phosphoproteome of Rhodotorula toruloides CGMCC 2.1389 under Pi-limitation and Pi-repletion. In total, proteome analysis identified 3,556 proteins and the phosphoproteome analysis identified 1,649 phosphoproteins contained 5,659 phosphosites including 4,499 pSer, 978 pThr, and 182 pTyr. We found Pi-starvation-induced autophagy was regulated by autophagy-related proteins, but not the PHO pathway. When ATG9 was knocked down, the engineered strains produced significantly less lipids under Pi-limitation, suggesting that autophagy required Atg9 in R. toruloides and that was conducive to lipid accumulation. Conclusion Our results provide new insights into autophagy regulation under Pi-limitation and lipid accumulation in oleaginous yeast, which should be valuable to guide further mechanistic study of oleaginicity and genetic engineering for advanced lipid producing cell factory.
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Affiliation(s)
- Ya-nan Wang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Fang-jie Liu
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Hong-di Liu
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Yue Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Xiang Jiao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China
| | - Ming-liang Ye
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, CAS, Dalian, China,Ming-liang Ye,
| | - Zong-bao Kent Zhao
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Zong-bao Kent Zhao,
| | - Su-fang Zhang
- Laboratory of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, China,*Correspondence: Su-fang Zhang, ,
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38
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Chen WF, Wang HF, Wang Y, Liu ZG, Xu BH. AmAtg2B-Mediated Lipophagy Regulates Lipolysis of Pupae in Apis mellifera. Int J Mol Sci 2023; 24:2096. [PMID: 36768418 PMCID: PMC9916532 DOI: 10.3390/ijms24032096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 01/21/2023] Open
Abstract
Lipophagy plays an important role in regulating lipid metabolism in mammals. The exact function of autophagy-related protein 2 (Atg2) has been investigated in mammals, but research on the existence and functions of Atg2 in Apis mellifera (AmAtg2) is still limited. Here, autophagy occurred in honeybee pupae, which targeted lipid droplets (LDs) in fat body, namely lipophagy, which was verified by co-localization of LDs with microtubule-associated protein 1A/1B light chain 3 beta (LC3). Moreover, AmAtg2 homolog B (AmAtg2B) was expressed specifically in pupal fat body, which indicated that AmAtg2B might have special function in fat body. Further, AmAtg2B antibody neutralization and AmAtg2B knock-down were undertaken to verify the functions in pupae. Results showed that low expression of AmAtg2B at the protein and transcriptional levels led to lipophagy inhibition, which down-regulated the expression levels of proteins and genes related to lipolysis. Altogether, results in this study systematically revealed that AmAtg2B interfered with lipophagy and then caused abnormal lipolysis in the pupal stage.
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Affiliation(s)
| | | | | | | | - Bao-Hua Xu
- College of Animal Science and Technology, Shandong Agricultural University, Tai’an 271018, China
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Capitanio C, Bieber A, Wilfling F. How Membrane Contact Sites Shape the Phagophore. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231162495. [PMID: 37366413 PMCID: PMC10243513 DOI: 10.1177/25152564231162495] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/15/2023] [Accepted: 02/18/2023] [Indexed: 06/28/2023]
Abstract
During macroautophagy, phagophores establish multiple membrane contact sites (MCSs) with other organelles that are pivotal for proper phagophore assembly and growth. In S. cerevisiae, phagophore contacts have been observed with the vacuole, the ER, and lipid droplets. In situ imaging studies have greatly advanced our understanding of the structure and function of these sites. Here, we discuss how in situ structural methods like cryo-CLEM can give unprecedented insights into MCSs, and how they help to elucidate the structural arrangements of MCSs within cells. We further summarize the current knowledge of the contact sites in autophagy, focusing on autophagosome biogenesis in the model organism S. cerevisiae.
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Affiliation(s)
- Cristina Capitanio
- Department of Molecular Machines and
Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
- Aligning Science Across Parkinson's (ASAP)
Collaborative Research Network, Chevy Chase, MD, USA
| | - Anna Bieber
- Department of Molecular Machines and
Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
- Aligning Science Across Parkinson's (ASAP)
Collaborative Research Network, Chevy Chase, MD, USA
| | - Florian Wilfling
- Mechanisms of Cellular Quality Control, Max Planck Institute of Biophysics, Frankfurt a. M., Germany
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Vargas Duarte P, Reggiori F. The Organization and Function of the Phagophore-ER Membrane Contact Sites. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231183898. [PMID: 37465355 PMCID: PMC10350784 DOI: 10.1177/25152564231183898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/06/2023] [Accepted: 06/06/2023] [Indexed: 07/20/2023]
Abstract
Macroautophagy is characterized by the de novo formation of double-membrane vesicles termed autophagosomes. The precursor structure of autophagosomes is a membrane cistern called phagophore, which elongates through a massive acquisition of lipids until closure. The phagophore establishes membrane-contact sites (MCSs) with the endoplasmic reticulum (ER), where conserved ATG proteins belonging to the ATG9 lipid scramblase, ATG2 lipid transfer and Atg18/WIPI4 β-propeller families concentrate. Several recent in vivo and in vitro studies have uncovered the relevance of these proteins and MCSs in the lipid supply required for autophagosome formation. Although important conceptual advances have been reached, the functional interrelationship between ATG9, ATG2 and Atg18/WIPI4 proteins at the phagophore-ER MCSs and their role in the phagophore expansion are not completely understood. In this review, we describe the current knowledge about the structure, interactions, localizations, and molecular functions of these proteins, with a particular emphasis on the yeast Saccharomyces cerevisiae and mammalian systems.
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Affiliation(s)
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus C, Denmark
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Chen A, Ding WX, Ni HM. Scramblases as Regulators of Autophagy and Lipid Homeostasis: Implications for NAFLD. AUTOPHAGY REPORTS 2022; 1:143-160. [PMID: 35509327 PMCID: PMC9066413 DOI: 10.1080/27694127.2022.2055724] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Equilibration of phospholipids between the two monolayers of the lipid bilayer of cellular membranes is mediated by scramblases acting as phospholipid shuttling proteins that are critical for cellular function, particularly during inter-organelle contact. Recent work has identified several protein scramblases, including TMEM41B, VMP1 and ATG9 that are critical in autophagy. More recently, ATG9, TMEM41B, and VMP1 have also been discovered to be important regulators of cellular lipid homeostasis. In vivo mouse models involving ablation of TMEM41B in liver have shown that knockout of these proteins can lead to rapid development of non-alcoholic steatohepatitis (NASH) and systemic dyslipidemia, though this has not been explored yet with ATG9. The resulting phenotype is likely due to the combined effects of a severe lipid secretion defect caused by stalled neutral lipids export from the endoplasmic reticulum (ER) membrane bilayer coupled with increased lipogenesis. Here we briefly discuss recent exciting findings on the topic of scramblases in autophagy, their relevance to human non-alcoholic fatty liver disease (NAFLD)/NASH, as well as future directions in this research.
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Affiliation(s)
- Allen Chen
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA
- Department of Internal Medicine, The University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Hong-Min Ni
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA
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Huang K, Lin Y, Wang K, Shen J, Wei D. ARFIP2 Regulates EMT and Autophagy in Hepatocellular Carcinoma in Part Through the PI3K/Akt Signalling Pathway. J Hepatocell Carcinoma 2022; 9:1323-1339. [PMID: 36573219 PMCID: PMC9789708 DOI: 10.2147/jhc.s392056] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Purpose ARFIP2, a canonical BAR domain-containing protein, is closely associated with regulating cargo exit from the Golgi. However, the potential biological functions of ARFIP2 in hepatocellular carcinoma (HCC) have not been well investigated. This study aimed to explore the critical role of ARFIP2 in HCC cells. Methods The expression of proteins related to epithelial to mesenchymal transition (EMT) and cell autophagy in HCC cells and tissues was assayed by quantitative real-time PCR, Western blotting, immunohistochemistry and immunofluorescence staining. The ability of cells to proliferate, migrate and invade was detected by Cell Counting Kit-8, Transwell migration and invasion assays. In addition, the function of ARFIP2 in vivo was assessed using a tumour xenograft model. Results ARFIP2 expression is significantly upregulated in early recurrent and metastatic HCC patients and was positively correlated with a poor prognosis. ARFIP2 overexpression promoted cell proliferation, migration, and invasion by inducing EMT and inhibiting autophagy in vitro. Furthermore, the regulatory effects of ARFIP2 on autophagy and EMT were partially attributed to its regulation of the PI3K/AKT signalling pathway. The in vivo results also showed that ARFIP2 modulates HCC progression. Conclusion Our results substantiate a novel mechanism by which ARFIP2 can regulate the activity/phosphorylation of Akt to promote EMT and inhibit autophagy in part via the PI3K/Akt signalling pathway. The ARFIP2/PI3K/Akt axis may be a potential diagnostic biomarker and therapeutic target for HCC.
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Affiliation(s)
- Kaida Huang
- Department of Oncology, Xiamen Haicang Hospital, Xiamen, People’s Republic of China
| | - Yubiao Lin
- Department of Oncology, Xiamen Haicang Hospital, Xiamen, People’s Republic of China
| | - Keyin Wang
- Department of Infectious Diseases, Affiliated Hospital of Jiaxing University, Jiaxing, People’s Republic of China
| | - Jianfen Shen
- Department of Central Laboratory, Affiliated Hospital of Jiaxing University, Jiaxing, People’s Republic of China
| | - Dahai Wei
- Department of Infectious Diseases, Affiliated Hospital of Jiaxing University, Jiaxing, People’s Republic of China,Department of Central Laboratory, Affiliated Hospital of Jiaxing University, Jiaxing, People’s Republic of China,Institute of Hepatology, Affiliated Hospital of Jiaxing University, Jiaxing, People’s Republic of China,Correspondence: Dahai Wei, Institute of Hepatology, Affiliated Hospital of Jiaxing University, Jiaxing, People’s Republic of China, Tel/Fax +86-573-89975669, Email
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Gudmundsson SR, Kallio KA, Vihinen H, Jokitalo E, Ktistakis N, Eskelinen EL. Morphology of Phagophore Precursors by Correlative Light-Electron Microscopy. Cells 2022; 11:cells11193080. [PMID: 36231043 PMCID: PMC9562894 DOI: 10.3390/cells11193080] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/16/2022] Open
Abstract
Autophagosome biogenesis occurs in the transient subdomains of the endoplasmic reticulum that are called omegasomes, which, in fluorescence microscopy, appear as small puncta, which then grow in diameter and finally shrink and disappear once the autophagosome is complete. Autophagosomes are formed by phagophores, which are membrane cisterns that elongate and close to form the double membrane that limits autophagosomes. Earlier electron-microscopy studies showed that, during elongation, phagophores are lined by the endoplasmic reticulum on both sides. However, the morphology of the very early phagophore precursors has not been studied at the electron-microscopy level. We used live-cell imaging of cells expressing markers of phagophore biogenesis combined with correlative light-electron microscopy, as well as electron tomography of ATG2A/B-double-deficient cells, to reveal the high-resolution morphology of phagophore precursors in three dimensions. We showed that phagophores are closed or nearly closed into autophagosomes already at the stage when the omegasome diameter is still large. We further observed that phagophore precursors emerge next to the endoplasmic reticulum as bud-like highly curved membrane cisterns with a small opening to the cytosol. The phagophore precursors then open to form more flat cisterns that elongate and curve to form the classically described crescent-shaped phagophores.
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Affiliation(s)
- Sigurdur Runar Gudmundsson
- Molecular and Integrative Biosciences, University of Helsinki, 00790 Helsinki, Finland
- Biomedical Center, School of Health Sciences, University of Iceland, 101 Reykjavik, Iceland
| | - Katri A. Kallio
- Molecular and Integrative Biosciences, University of Helsinki, 00790 Helsinki, Finland
| | - Helena Vihinen
- Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Eija Jokitalo
- Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | | | - Eeva-Liisa Eskelinen
- Institute of Biomedicine, University of Turku, 20520 Turku, Finland
- Correspondence: ; Tel.: +358-505115631
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Nondegradable ubiquitinated ATG9A organizes Golgi integrity and dynamics upon stresses. Cell Rep 2022; 40:111195. [PMID: 35977480 DOI: 10.1016/j.celrep.2022.111195] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/06/2022] [Accepted: 07/20/2022] [Indexed: 11/22/2022] Open
Abstract
ATG9A is a highly conserved membrane protein required for autophagy initiation. It is trafficked from the trans-Golgi network (TGN) to the phagophore to act as a membrane source for autophagosome expansion. Here, we show that ATG9A is not just a passenger protein in the TGN but rather works in concert with GRASP55, a stacking factor for Golgi structure, to organize Golgi dynamics and integrity. Upon heat stress, the E3 ubiquitin ligase MARCH9 is promoted to ubiquitinate ATG9A in the form of K63 conjugation, and the nondegradable ubiquitinated ATG9A disperses from the Golgi apparatus to the cytoplasm more intensely, accompanied by inhibiting GRASP55 oligomerization, further resulting in Golgi fragmentation. Knockout of ATG9A or MARCH9 largely prevents Golgi fragmentation and protects Golgi functions under heat and other Golgi stresses. Our results reveal a noncanonical function of ATG9A for Golgi dynamics and suggest the pathway for sensing Golgi stress via the MARCH9/ATG9A axis.
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45
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Ballesteros A, Swartz KJ. Regulation of membrane homeostasis by TMC1 mechanoelectrical transduction channels is essential for hearing. SCIENCE ADVANCES 2022; 8:eabm5550. [PMID: 35921424 PMCID: PMC9348795 DOI: 10.1126/sciadv.abm5550] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The mechanoelectrical transduction (MET) channel in auditory hair cells converts sound into electrical signals, enabling hearing. Transmembrane-like channel 1 and 2 (TMC1 and TMC2) are implicated in forming the pore of the MET channel. Here, we demonstrate that inhibition of MET channels, breakage of the tip links required for MET, or buffering of intracellular Ca... induces pronounced phosphatidylserine externalization, membrane blebbing, and ectosome release at the hair cell sensory organelle, culminating in the loss of TMC1. Membrane homeostasis triggered by MET channel inhibition requires Tmc1 but not Tmc2, and three deafness-causing mutations in Tmc1 cause constitutive phosphatidylserine externalization that correlates with deafness phenotype. Our results suggest that, in addition to forming the pore of the MET channel, TMC1 is a critical regulator of membrane homeostasis in hair cells, and that Tmc1-related hearing loss may involve alterations in membrane homeostasis.
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Interplay between Lipid Metabolism, Lipid Droplets, and DNA Virus Infections. Cells 2022; 11:cells11142224. [PMID: 35883666 PMCID: PMC9324743 DOI: 10.3390/cells11142224] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/05/2022] [Accepted: 07/09/2022] [Indexed: 12/10/2022] Open
Abstract
Lipid droplets (LDs) are cellular organelles rich in neutral lipids such as triglycerides and cholesterol esters that are coated by a phospholipid monolayer and associated proteins. LDs are known to play important roles in the storage and availability of lipids in the cell and to serve as a source of energy reserve for the cell. However, these structures have also been related to oxidative stress, reticular stress responses, and reduced antigen presentation to T cells. Importantly, LDs are also known to modulate viral infection by participating in virus replication and assembly. Here, we review and discuss the interplay between neutral lipid metabolism and LDs in the replication cycle of different DNA viruses, identifying potentially new molecular targets for the treatment of viral infections.
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Hanna MG, Suen PH, Wu Y, Reinisch KM, De Camilli P. SHIP164 is a chorein motif lipid transfer protein that controls endosome-Golgi membrane traffic. J Cell Biol 2022; 221:213192. [PMID: 35499567 PMCID: PMC9067936 DOI: 10.1083/jcb.202111018] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 03/07/2022] [Accepted: 04/08/2022] [Indexed: 02/03/2023] Open
Abstract
Cellular membranes differ in protein and lipid composition as well as in the protein-lipid ratio. Thus, progression of membranous organelles along traffic routes requires mechanisms to control bilayer lipid chemistry and their abundance relative to proteins. The recent structural and functional characterization of VPS13-family proteins has suggested a mechanism through which lipids can be transferred in bulk from one membrane to another at membrane contact sites, and thus independently of vesicular traffic. Here, we show that SHIP164 (UHRF1BP1L) shares structural and lipid transfer properties with these proteins and is localized on a subpopulation of vesicle clusters in the early endocytic pathway whose membrane cargo includes the cation-independent mannose-6-phosphate receptor (MPR). Loss of SHIP164 disrupts retrograde traffic of these organelles to the Golgi complex. Our findings raise the possibility that bulk transfer of lipids to endocytic membranes may play a role in their traffic.
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Affiliation(s)
- Michael G. Hanna
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT,Department of Cell Biology, Yale University School of Medicine, New Haven, CT,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Patreece H. Suen
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Yumei Wu
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT,Department of Cell Biology, Yale University School of Medicine, New Haven, CT,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT,Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD,Karin M. Reinisch:
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT,Department of Cell Biology, Yale University School of Medicine, New Haven, CT,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT,Kavli Institue for Neuroscience, Yale University School of Medicine, New Haven, CT,Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD,Correspondence to Pietro De Camilli:
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48
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Hama Y, Morishita H, Mizushima N. Regulation of ER-derived membrane dynamics by the DedA domain-containing proteins VMP1 and TMEM41B. EMBO Rep 2022; 23:e53894. [PMID: 35044051 PMCID: PMC8811646 DOI: 10.15252/embr.202153894] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/30/2021] [Accepted: 12/23/2021] [Indexed: 02/05/2023] Open
Abstract
The endoplasmic reticulum (ER) is a central hub for the biogenesis of various organelles and lipid-containing structures. Recent studies suggest that vacuole membrane protein 1 (VMP1) and transmembrane protein 41B (TMEM41B), multispanning ER membrane proteins, regulate the formation of many of these ER-derived structures, including autophagosomes, lipid droplets, lipoproteins, and double-membrane structures for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. VMP1 and TMEM41B possess a DedA domain that is widely distributed not only in eukaryotes but also in prokaryotes and predicted to adopt a characteristic structure containing two reentrant loops. Furthermore, recent studies show that both proteins have lipid scrambling activity. Based on these findings, the potential roles of VMP1 and TMEM41B in the dynamic remodeling of ER membranes and the biogenesis of ER-derived structures are discussed.
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Affiliation(s)
- Yutaro Hama
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
| | - Hideaki Morishita
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan,Department of PhysiologyGraduate School of MedicineJuntendo UniversityTokyoJapan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular BiologyGraduate School of MedicineThe University of TokyoTokyoJapan
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