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Gamallat Y, Alwazan H, Turko R, Dang V, Seyedi S, Ghosh S, Bismar TA. Elevated LAMTOR4 Expression Is Associated with Lethal Prostate Cancer and Its Knockdown Decreases Cell Proliferation, Invasion, and Migration In Vitro. Int J Mol Sci 2024; 25:8100. [PMID: 39125671 PMCID: PMC11312415 DOI: 10.3390/ijms25158100] [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: 05/17/2024] [Revised: 07/18/2024] [Accepted: 07/22/2024] [Indexed: 08/12/2024] Open
Abstract
Late endosomal/lysosomal adaptor, MAPK and mTOR, or LAMTOR, is a scaffold protein complex that senses nutrients and integrates growth factor signaling. The role of LAMTOR4 in tumorigenesis is still unknown. However, there is a considerable possibility that LAMTOR4 is directly involved in tumor cell proliferation and metastasis. In the current study, we investigated the protein expression of LAMTOR4 in a cohort of 314 men who were undergoing transurethral resection of prostate (TURP) consisting of incidental, advanced and castration-resistant cases. We also correlated the data with ERG and PTEN genomic status and clinicopathological features including Gleason score and patients' outcome. Additionally, we performed in vitro experiments utilizing knockdown of LAMTOR4 in prostate cell lines, and we performed mRNA expression assessment using TCGA prostate adenocarcinoma (TCGA-PRAD) to explore the potential differentially expressed genes and pathways associated with LAMTOR4 overexpression in PCa patients. Our data indicate that high LAMTOR4 protein expression was significantly associated with poor overall survival (OS) (HR: 1.44, CI: 1.01-2.05, p = 0.047) and unfavorable cause-specific survival (CSS) (HR: 1.71, CI: 1.06-2.77, p = 0.028). Additionally, when high LAMTOR4 expression was combined with PTEN-negative cases (score 0), we found significantly poorer OS (HR: 2.22, CI: 1.37-3.59, p = 0.001) and CSS (HR: 3.46, CI: 1.86-6.46, p < 0.0001). Furthermore, ERG-positive cases with high LAMTOR4 exhibited lower OS (HR: 1.98, CI: 1.18-3.31, p = 0.01) and CSS (HR: 2.54, CI: 1.32-4.87, p = 0.005). In vitro assessment showed that knockdown of LAMTOR4 decreases PCa cell proliferation, migration, and invasion. Our data further showed that knockdown of LAMTOR4 in the LNCaP cell line significantly dysregulated the β catenin/mTOR pathway and tumorigenesis associated pathways. Inhibiting components of the mTOR pathway, including LAMTOR4, might offer a strategy to inhibit tumor progression and metastasis in prostate cancer.
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Affiliation(s)
- Yaser Gamallat
- Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (Y.G.); (R.T.); (V.D.)
- Departments of Oncology, Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Huseen Alwazan
- Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (Y.G.); (R.T.); (V.D.)
| | - Rasoul Turko
- Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (Y.G.); (R.T.); (V.D.)
| | - Vincent Dang
- Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (Y.G.); (R.T.); (V.D.)
| | - Sima Seyedi
- Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (Y.G.); (R.T.); (V.D.)
- Departments of Oncology, Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Sunita Ghosh
- Departments of Mathematical and Statistical Sciences and Medical Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2R7, Canada;
| | - Tarek A. Bismar
- Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (Y.G.); (R.T.); (V.D.)
- Departments of Oncology, Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Tom Baker Cancer Center, Alberta Health Services, Calgary, AB T2N 4N1, Canada
- Prostate Cancer Centre, Rockyview General Hospital, Calgary, AB T2V 1P9, Canada
- Alberta Precision Labs, Rockyview General Hospital, Calgary, AB T2V 1P9, Canada
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Liu Y, Wang R, Liu J, Fan M, Ye Z, Hao Y, Xie F, Wang T, Jiang Y, Liu N, Cui X, Lv Q, Yan L. The vacuolar fusion regulated by HOPS complex promotes hyphal initiation and penetration in Candida albicans. Nat Commun 2024; 15:4131. [PMID: 38755250 PMCID: PMC11099166 DOI: 10.1038/s41467-024-48525-5] [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: 10/11/2023] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
The transition between yeast and hyphae is crucial for regulating the commensalism and pathogenicity in Candida albicans. The mechanisms that affect the invasion of hyphae in solid media, whose deficiency is more related to the pathogenicity of C. albicans, have not been elucidated. Here, we found that the disruption of VAM6 or VPS41 which are components of the homotypic vacuolar fusion and protein sorting (HOPS) complex, or the Rab GTPase YPT72, all responsible for vacuole fusion, led to defects in hyphal growth in both liquid and solid media, but more pronounced on solid agar. The phenotypes of vac8Δ/Δ and GTR1OE-vam6Δ/Δ mutants indicated that these deficiencies are mainly caused by the reduced mechanical forces that drive agar and organs penetration, and confirmed that large vacuoles are required for hyphal mechanical penetration. In summary, our study revealed that large vacuoles generated by vacuolar fusion support hyphal penetration and provided a perspective to refocus attention on the role of solid agar in evaluating C. albicans invasion.
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Affiliation(s)
- Yu Liu
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China
| | - Ruina Wang
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China
| | - Jiacun Liu
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China
| | - Mengting Fan
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, PR China
| | - Zi Ye
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China
| | - Yumeng Hao
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China
| | - Fei Xie
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China
| | - Ting Wang
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China
| | - Yuanying Jiang
- School of Medicine, Tongji University, Shanghai, 200092, PR China
| | - Ningning Liu
- State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, PR China.
| | - Xiaoyan Cui
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, PR China.
| | - Quanzhen Lv
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China.
| | - Lan Yan
- Center for Basic Research and Innovation of Medicine and Pharmacy (MOE), School of Pharmacy, Naval Medical University, Shanghai, 200433, PR China.
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Tran LT, Akıl C, Senju Y, Robinson RC. The eukaryotic-like characteristics of small GTPase, roadblock and TRAPPC3 proteins from Asgard archaea. Commun Biol 2024; 7:273. [PMID: 38472392 DOI: 10.1038/s42003-024-05888-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 02/06/2024] [Indexed: 03/14/2024] Open
Abstract
Membrane-enclosed organelles are defining features of eukaryotes in distinguishing these organisms from prokaryotes. Specification of distinct membranes is critical to assemble and maintain discrete compartments. Small GTPases and their regulators are the signaling molecules that drive membrane-modifying machineries to the desired location. These signaling molecules include Rab and Rag GTPases, roadblock and longin domain proteins, and TRAPPC3-like proteins. Here, we take a structural approach to assess the relatedness of these eukaryotic-like proteins in Asgard archaea, the closest known prokaryotic relatives to eukaryotes. We find that the Asgard archaea GTPase core domains closely resemble eukaryotic Rabs and Rags. Asgard archaea roadblock, longin and TRAPPC3 domain-containing proteins form dimers similar to those found in the eukaryotic TRAPP and Ragulator complexes. We conclude that the emergence of these protein architectures predated eukaryogenesis, however further adaptations occurred in proto-eukaryotes to allow these proteins to regulate distinct internal membranes.
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Affiliation(s)
- Linh T Tran
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530, Japan
| | - Caner Akıl
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530, Japan
- Division of Structural Biology, University of Oxford, Oxford, England
| | - Yosuke Senju
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530, Japan
| | - Robert C Robinson
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530, Japan.
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand.
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Zhao L, Gao N, Peng X, Chen L, Meng T, Jiang C, Jin J, Zhang J, Duan Q, Tian H, Weng L, Wang X, Tan X, Li Y, Qin H, Yuan J, Ge X, Deng L, Wang P. TRAF4-Mediated LAMTOR1 Ubiquitination Promotes mTORC1 Activation and Inhibits the Inflammation-Induced Colorectal Cancer Progression. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2301164. [PMID: 38229144 DOI: 10.1002/advs.202301164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 11/28/2023] [Indexed: 01/18/2024]
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) is a conserved serine/threonine kinase that integrates various environmental signals to regulate cell growth and metabolism. mTORC1 activation requires tethering to lysosomes by the Ragulator-Rag complex. However, the dynamic regulation of the interaction between Ragulator and Rag guanosine triphosphatase (GTPase) remains unclear. In this study, that LAMTOR1, an essential component of Ragulator, is dynamically ubiquitinated depending on amino acid abundance is reported. It is found that the E3 ligase TRAF4 directly interacts with LAMTOR1 and catalyzes the K63-linked polyubiquitination of LAMTOR1 at K151. Ubiquitination of LAMTOR1 by TRAF4 promoted its binding to Rag GTPases and enhanced mTORC1 activation, K151R knock-in or TRAF4 knock-out blocks amino acid-induced mTORC1 activation and accelerates the development of inflammation-induced colon cancer. This study revealed that TRAF4-mediated LAMTOR1 ubiquitination is a regulatory mechanism for mTORC1 activation and provides a therapeutic target for diseases involving mTORC1 dysregulation.
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Affiliation(s)
- Linlin Zhao
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Ni Gao
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Xiaoping Peng
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Lei Chen
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Tong Meng
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
- Department of Orthopedics, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200940, P. R. China
| | - Cong Jiang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Jiali Jin
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Jiawen Zhang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Qiuhui Duan
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Hongling Tian
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Linjun Weng
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Xinbo Wang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Xiao Tan
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Yaxu Li
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Huanlong Qin
- Department of Gastrointestinal Surgery, Shanghai Tenth People's Hospital, Tongji University, Shanghai, 200092, P. R. China
- Research Institute of Intestinal Diseases, Tongji University School of Medicine, Shanghai, 200092, P. R. China
| | - Jian Yuan
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, 200092, P. R. China
- Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, P. R. China
| | - Xin Ge
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
| | - Lu Deng
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P. R. China
| | - Ping Wang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Shanghai Frontiers Science Center of Nanocatalytic Medicine, School of Medicine, Tongji University, Shanghai, 200092, P. R. China
- Department of Biochemistry and Molecular Biology, Tongji University School of Medicine, Shanghai, 200092, P. R. China
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Ivanova I, Shen K. Structures and Functions of the Human GATOR1 Complex. Subcell Biochem 2024; 104:269-294. [PMID: 38963491 DOI: 10.1007/978-3-031-58843-3_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Eukaryotic cells coordinate available nutrients with their growth through the mechanistic target of rapamycin complex 1 (mTORC1) pathway, in which numerous evolutionarily conserved protein complexes survey and transmit nutrient inputs toward mTORC1. mTORC1 integrates these inputs and activates downstream anabolic or catabolic programs that are in tune with cellular needs, effectively maintaining metabolic homeostasis. The GAP activity toward Rags-1 (GATOR1) protein complex is a critical negative regulator of the mTORC1 pathway and, in the absence of amino acid inputs, is activated to turn off mTORC1 signaling. GATOR1-mediated inhibition of mTORC1 signaling is tightly regulated by an ensemble of protein complexes that antagonize or promote its activity in response to the cellular nutrient environment. Structural, biochemical, and biophysical studies of the GATOR1 complex and its interactors have advanced our understanding of how it regulates cellular metabolism when amino acids are limited. Here, we review the current research with a focus on GATOR1 structure, its enzymatic mechanism, and the growing group of proteins that regulate its activity. Finally, we discuss the implication of GATOR1 dysregulation in physiology and human diseases.
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Affiliation(s)
- Ilina Ivanova
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA.
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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Linde-Garelli KY, Rogala KB. Structural mechanisms of the mTOR pathway. Curr Opin Struct Biol 2023; 82:102663. [PMID: 37572585 DOI: 10.1016/j.sbi.2023.102663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/01/2023] [Accepted: 07/07/2023] [Indexed: 08/14/2023]
Abstract
The mTOR signaling pathway is essential for regulating cell growth and mammalian metabolism. The mTOR kinase forms two complexes, mTORC1 and mTORC2, which respond to external stimuli and regulate differential downstream targets. Cellular membrane-associated translocation mediates function and assembly of the mTOR complexes, and recent structural studies have begun uncovering the molecular basis by which the mTOR pathway (1) regulates signaling inputs, (2) recruits substrates, (3) localizes to biological membranes, and (4) becomes activated. Moreover, indications of dysregulated mTOR signaling are implicated in a wide range of diseases and an increasingly comprehensive understanding of structural mechanisms is driving novel translational development.
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Affiliation(s)
- Karen Y Linde-Garelli
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Kacper B Rogala
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA.
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7
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Niu F, Li Z, Ren Y, Li Z, Guan H, Li Y, Zhang Y, Li Y, Yang J, Qian L, Shi W, Fan X, Li J, Shi L, Yu Y, Xiong Y. Aberrant hyper-expression of the RNA binding protein GIGYF2 in endothelial cells modulates vascular aging and function. Redox Biol 2023; 65:102824. [PMID: 37517320 PMCID: PMC10400931 DOI: 10.1016/j.redox.2023.102824] [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: 05/26/2023] [Revised: 07/13/2023] [Accepted: 07/23/2023] [Indexed: 08/01/2023] Open
Abstract
Vascular endothelial cells (ECs) senescence plays a crucial role in vascular aging that promotes the initiation and progression of cardiovascular disease. The mutation of Grb10-interacting GYF protein 2 (GIGYF2) is strongly associated with the pathogenesis of aging-related diseases, whereas its role in regulating ECs senescence and dysfunction still remains elusive. In this study, we found aberrant hyperexpression of GIGYF2 in senescent human ECs and aortas of old mice. Silencing GIGYF2 in senescent ECs suppressed eNOS-uncoupling, senescence, and endothelial dysfunction. Conversely, in nonsenescent cells, overexpressing GIGYF2 promoted eNOS-uncoupling, cellular senescence, endothelial dysfunction, and activation of the mTORC1-SK61 pathway, which were ablated by rapamycin or antioxidant N-Acetyl-l-cysteine (NAC). Transcriptome analysis revealed that staufen double-stranded RNA binding protein 1 (STAU1) is remarkably downregulated in the GIGYF2-depleted ECs. STAU1 depletion significantly attenuated GIGYF2-induced cellular senescence, dysfunction, and inflammation in young ECs. Furthermore, we disclosed that GIGYF2 acting as an RNA binding protein (RBP) enhances STAU1 mRNA stability, and that the intron region of the late endosomal/lysosomal adaptor MAPK and mTOR activator 4 (LAMTOR4) could bind to STAU1 protein to upregulate LAMTOR4 expression. Immunofluorescence staining showed that GIGYF2 overexpression promoted the translocation of mTORC1 to lysosome. In the mice model, GIGYF2flox/flox Cdh-Cre+ mice protected aged mice from aging-associated vascular endothelium-dependent relaxation and arterial stiffness. Our work discloses that GIGYF2 serving as an RBP enhances the mRNA stability of STAU1 that upregulates LAMTOR4 expression through binding with its intron region, which activates the mTORC1-S6K1 signaling via recruitment of mTORC1 to the lysosomal membrane, ultimately leading to ECs senescence, dysfunction, and vascular aging. Disrupting the GIGYF2-STAU1-mTORC1 signaling cascade may represent a promising therapeutic approach against vascular aging and aging-related cardiovascular diseases.
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Affiliation(s)
- Fanglin Niu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Zhuozhuo Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Yuanyuan Ren
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Zi Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Hua Guan
- Shaanxi Key Laboratory of Ischemic Cardiovascular Diseases & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, Shaanxi, 710018, PR China
| | - Yang Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Yan Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Yirong Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Junle Yang
- Department of Radiology, Xi' an No.3 Hospital, The Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710018, PR China
| | - Lu Qian
- Department of Endocrinology, Xi' an No.3 Hospital, The Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710018, PR China; Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710018, PR China
| | - Wenzhen Shi
- Medical Research Center, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710018, PR China; Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710018, PR China
| | - Xiaobin Fan
- Department of Obstetrics and Gynecology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710018, PR China
| | - Jinli Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Lele Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China
| | - Yi Yu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China.
| | - Yuyan Xiong
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, School of Medicine, Northwest University, Xi'an, Shaanxi, 710069, PR China; Xi'an Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710018, PR China.
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Xu J, Quan G, Huang W, Jiang J. VSIG2 promotes malignant progression of pancreatic ductal adenocarcinoma by enhancing LAMTOR2-mediated mTOR activation. Cell Commun Signal 2023; 21:223. [PMID: 37626304 PMCID: PMC10463957 DOI: 10.1186/s12964-023-01209-x] [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: 06/30/2023] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is one of the most intractable malignancies to overcome clinically due to its insidious onset as well as rapid progression. It is urgent to seek new diagnostic markers and therapeutic targets in order to furthest ameliorate the prognosis of patients with PDAC. V-set and immunoglobulin domain containing 2 (VSIG2) belongs to immunoglobulin superfamily (IgSF), which function as coinhibitory molecule to mediate immune evasion of tumors. Nevertheless, the role of VSIG2 in PDAC and related mechanism still keep unclear. METHODS Different expression of VSIG2 in PDAC tissues and cells were detected by bioinformatic analysis, immunohistochemistry, real-time quantitative PCR as well as western blotting. CCK-8, colony formation, Transwell assay, and scratch experiment were utilized to assess proliferation, invasion and migration properties of PDAC cells. The relationship of VSIG2 with late endosomal/lysosomal adaptor, MAPK and MTOR activator 2 (LAMTOR2) and mechanistic target of rapamycin (mTOR) was identified using mass spectrometry, co-immunoprecipitation and immunofluorescence. GO and KEGG enrichment analysis were performed for further pathway verification using western blotting. Additionally, subcutaneous xenograft tumor model and clinical samples analysis were implemented to further elucidate the oncogenic effect of VSIG2 on PDAC in vivo and clinically. RESULTS VSIG2 was highly expressed in PDAC tissues and cells. Overexpression of VSIG2 facilitated the proliferation, invasion and migration abilities of PDAC cells, while VSIG2-inhibition exerted opposite effects. Mechanistically, VSIG2 could simultaneously bind to LAMTOR2 and mTOR, thereby enhancing interaction between two molecules, which resulted in elevated phosphorylation-modificatory activation of mTOR and downstream key molecules. Clinically, up-regulation of VSIG2 was positively associated with advanced stage, overall survival and disease-free survival of PDAC patients. CONCLUSIONS Our study disclosed that VSIG2 was overexpressed in PDAC, which promoted the proliferation, invasion and metastasis. Mechanically, VSIG2 acted as a scaffold to recruit LAMTOR2 and mTOR simultaneously, stabilize the interaction between them, thus enhancing LAMTOR2-mediated mTOR phosphorylated activation. Collectively, VSIG2 could be exploited as a biomarker for diagnosis and prognosis monitor of PDAC in the future, meanwhile, targeting VSIG2 in PDAC management is expected to be a novel strategy. Video Abstract. Video Abstract.
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Affiliation(s)
- Jichuan Xu
- Department of Hepatobiliary, Pancreatic and Splenic Surgery, Affiliated Dongguan Hospital, Southern Medical University (Dongguan People's Hospital), 78 Wandao Road, Wanjiang Street, Dongguan City, Guangdong Province, 523058, People's Republic of China
| | - Gang Quan
- Department of Hepatobiliary, Pancreatic and Splenic Surgery, Affiliated Dongguan Hospital, Southern Medical University (Dongguan People's Hospital), 78 Wandao Road, Wanjiang Street, Dongguan City, Guangdong Province, 523058, People's Republic of China
- Department of Hepatobiliary Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Wei Huang
- Department of Hepatobiliary, Pancreatic and Splenic Surgery, Affiliated Dongguan Hospital, Southern Medical University (Dongguan People's Hospital), 78 Wandao Road, Wanjiang Street, Dongguan City, Guangdong Province, 523058, People's Republic of China
| | - Jianxin Jiang
- Department of Hepatobiliary, Pancreatic and Splenic Surgery, Affiliated Dongguan Hospital, Southern Medical University (Dongguan People's Hospital), 78 Wandao Road, Wanjiang Street, Dongguan City, Guangdong Province, 523058, People's Republic of China.
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9
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Tsujimoto K, Takamatsu H, Kumanogoh A. The Ragulator complex: delving its multifunctional impact on metabolism and beyond. Inflamm Regen 2023; 43:28. [PMID: 37173755 PMCID: PMC10175929 DOI: 10.1186/s41232-023-00278-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/01/2023] [Indexed: 05/15/2023] Open
Abstract
Our understanding of lysosomes has undergone a significant transformation in recent years, from the view that they are static organelles primarily responsible for the disposal and recycling of cellular waste to their recognition as highly dynamic structures. Current research posits that lysosomes function as a signaling hub that integrates both extracellular and intracellular stimuli, thereby regulating cellular homeostasis. The dysregulation of lysosomal function has been linked to a wide range of diseases. Of note, lysosomes contribute to the activation of mammalian target of rapamycin complex 1 (mTORC1), a key regulator of cellular metabolism. The Ragulator complex, a protein complex anchored on the lysosomal membrane, was initially shown to tether the mTORC1 complex to lysosomes. Recent research has substantially expanded our understanding of the roles of the Ragulator complex in lysosomes, including roles in the regulation of metabolism, inflammation, cell death, cell migration, and the maintenance of homeostasis, via interactions with various proteins. This review summarizes our current knowledge on the diverse functions of the Ragulator complex, highlighting important protein interactions.
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Affiliation(s)
- Kohei Tsujimoto
- Department of Respiratory Medicine and Clinical Immunology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
- Department of Immunopathology, Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, Japan
| | - Hyota Takamatsu
- Department of Respiratory Medicine and Clinical Immunology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
- Department of Immunopathology, Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, Japan.
| | - Atsushi Kumanogoh
- Department of Respiratory Medicine and Clinical Immunology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
- Department of Immunopathology, Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, Japan
- Center for Infectious Diseases Education and Research (CiDER), Osaka University, Suita, Osaka, Japan
- Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka, Japan
- Japan Agency for Medical Research and Development - Core Research for Evolutional Science and Technology (AMED-CREST), Osaka University, Osaka, Japan
- Center for Advanced Modalities and DDS (CAMaD), Osaka University, Osaka, Japan
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10
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Atre R, Sharma R, Vadim G, Solanki K, Wadhonkar K, Singh N, Patidar P, Khabiya R, Samaur H, Banerjee S, Baig MS. The indispensability of macrophage adaptor proteins in chronic inflammatory diseases. Int Immunopharmacol 2023; 119:110176. [PMID: 37104916 DOI: 10.1016/j.intimp.2023.110176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 04/06/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023]
Abstract
Adaptor proteins represent key signalling molecules involved in regulating immune responses. The host's innate immune system recognizes pathogens via various surface and intracellular receptors. Adaptor molecules are centrally involved in different receptor-mediated signalling pathways, acting as bridges between the receptors and other molecules. The presence of adaptors in major signalling pathways involved in the pathogenesis of various chronic inflammatory diseases has drawn attention toward the role of these proteins in such diseases. In this review, we summarize the importance and roles of different adaptor molecules in macrophage-mediated signalling in various chronic disease states. We highlight the mechanistic roles of adaptors and how they are involved in protein-protein interactions (PPI) via different domains to carry out signalling. Hence, we also provide insights into how targeting these adaptor proteins can be a good therapeutic strategy against various chronic inflammatory diseases.
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Affiliation(s)
- Rajat Atre
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Rahul Sharma
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Gaponenko Vadim
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Kundan Solanki
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Khandu Wadhonkar
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Neha Singh
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Pramod Patidar
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Rakhi Khabiya
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India; School of Pharmacy, Devi Ahilya Vishwavidyalaya, Indore, India
| | - Harshita Samaur
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Sreeparna Banerjee
- Department of Biological Sciences, Middle East Technical University, Ankara, Turkey.
| | - Mirza S Baig
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India.
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11
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Regulation of mTORC1 by the Rag GTPases. Biochem Soc Trans 2023; 51:655-664. [PMID: 36929165 DOI: 10.1042/bst20210038] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023]
Abstract
The Rag GTPases are an evolutionarily conserved family that play a crucial role in amino acid sensing by the mammalian target of rapamycin complex 1 (mTORC1). mTORC1 is often referred to as the master regulator of cell growth. mTORC1 hyperactivation is observed in multiple diseases such as cancer, obesity, metabolic disorders, and neurodegeneration. The Rag GTPases sense amino acid levels and form heterodimers, where RagA or RagB binds to RagC or RagD, to recruit mTORC1 to the lysosome where it becomes activated. Here, we review amino acid signaling to mTORC1 through the Rag GTPases.
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12
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Ni R, Li Z, Li L, Peng D, Ming Y, Li L, Liu Y. Rethinking glutamine metabolism and the regulation of glutamine addiction by oncogenes in cancer. Front Oncol 2023; 13:1143798. [PMID: 36959802 PMCID: PMC10029103 DOI: 10.3389/fonc.2023.1143798] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/24/2023] [Indexed: 03/09/2023] Open
Abstract
Glutamine, the most abundant non-essential amino acid in human blood, is crucial for cancer cell growth and cancer progression. Glutamine mainly functions as a carbon and nitrogen source for biosynthesis, energy metabolism, and redox homeostasis maintenance in cancer cells. Dysregulated glutamine metabolism is a notable metabolic characteristic of cancer cells. Some carcinogen-driven cancers exhibit a marked dependence on glutamine, also known as glutamine addiction, which has rendered the glutamine metabolic pathway a breakpoint in cancer therapeutics. However, some cancer cells can adapt to the glutamine unavailability by reprogramming metabolism, thus limiting the success of this therapeutic approach. Given the complexity of metabolic networks and the limited impact of inhibiting glutamine metabolism alone, the combination of glutamine metabolism inhibition and other therapeutic methods may outperform corresponding monotherapies in the treatment of cancers. This review summarizes the uptake, transport, and metabolic characteristics of glutamine, as well as the regulation of glutamine dependence by some important oncogenes in various cancers to emphasize the therapeutic potential of targeting glutamine metabolism. Furthermore, we discuss a glutamine metabolic pathway, the glutaminase II pathway, that has been substantially overlooked. Finally, we discuss the applicability of polytherapeutic strategies targeting glutamine metabolism to provide a new perspective on cancer therapeutics.
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Affiliation(s)
- Rui Ni
- Department of pharmacy, Daping Hospital, Army Medical University, Chongqing, China
| | - Ziwei Li
- Department of pharmacy, Daping Hospital, Army Medical University, Chongqing, China
| | - Li Li
- Department of pharmacy, Daping Hospital, Army Medical University, Chongqing, China
| | - Dan Peng
- Department of pharmacy, Daping Hospital, Army Medical University, Chongqing, China
| | - Yue Ming
- Department of pharmacy, Daping Hospital, Army Medical University, Chongqing, China
| | - Lin Li
- Department of pharmacy, Women and Children’s Hospital of Chongqing Medical University, Chongqing Health Center for Women and Children, Chongqing, China
- *Correspondence: Lin Li, ; Yao Liu,
| | - Yao Liu
- Department of pharmacy, Daping Hospital, Army Medical University, Chongqing, China
- *Correspondence: Lin Li, ; Yao Liu,
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13
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Singh J, Elhabashy H, Muthukottiappan P, Stepath M, Eisenacher M, Kohlbacher O, Gieselmann V, Winter D. Cross-linking of the endolysosomal system reveals potential flotillin structures and cargo. Nat Commun 2022; 13:6212. [PMID: 36266287 PMCID: PMC9584938 DOI: 10.1038/s41467-022-33951-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 10/06/2022] [Indexed: 12/24/2022] Open
Abstract
Lysosomes are well-established as the main cellular organelles for the degradation of macromolecules and emerging as regulatory centers of metabolism. They are of crucial importance for cellular homeostasis, which is exemplified by a plethora of disorders related to alterations in lysosomal function. In this context, protein complexes play a decisive role, regulating not only metabolic lysosomal processes but also lysosome biogenesis, transport, and interaction with other organelles. Using cross-linking mass spectrometry, we analyze lysosomes and early endosomes. Based on the identification of 5376 cross-links, we investigate protein-protein interactions and structures of lysosome- and endosome-related proteins. In particular, we present evidence for a tetrameric assembly of the lysosomal hydrolase PPT1 and a heterodimeric structure of FLOT1/FLOT2 at lysosomes and early endosomes. For FLOT1-/FLOT2-positive early endosomes, we identify >300 putative cargo proteins and confirm eleven substrates for flotillin-dependent endocytosis, including the latrophilin family of adhesion G protein-coupled receptors.
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Affiliation(s)
- Jasjot Singh
- Institute for Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, 53115, Bonn, Germany
| | - Hadeer Elhabashy
- Department of Protein Evolution, Max-Planck-Institute for Developmental Biology, 72076, Tübingen, Germany
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, 72076, Tübingen, Germany
- Department of Computer Science, University of Tübingen, 72076, Tübingen, Germany
| | - Pathma Muthukottiappan
- Institute for Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, 53115, Bonn, Germany
| | - Markus Stepath
- Medical Proteome-Center, Medical Faculty, Ruhr-University Bochum, 48801, Bochum, Germany
- Medical Proteome Analysis, Center for Protein Diagnostics, Ruhr-University Bochum, 48801, Bochum, Germany
| | - Martin Eisenacher
- Medical Proteome-Center, Medical Faculty, Ruhr-University Bochum, 48801, Bochum, Germany
- Medical Proteome Analysis, Center for Protein Diagnostics, Ruhr-University Bochum, 48801, Bochum, Germany
| | - Oliver Kohlbacher
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, 72076, Tübingen, Germany
- Department of Computer Science, University of Tübingen, 72076, Tübingen, Germany
- Institute for Translational Bioinformatics, University Hospital Tübingen, 72076, Tübingen, Germany
| | - Volkmar Gieselmann
- Institute for Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, 53115, Bonn, Germany
| | - Dominic Winter
- Institute for Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, 53115, Bonn, Germany.
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14
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Szadkowski D, Carreira LAM, Søgaard-Andersen L. A bipartite, low-affinity roadblock domain-containing GAP complex regulates bacterial front-rear polarity. PLoS Genet 2022; 18:e1010384. [PMID: 36067225 PMCID: PMC9481161 DOI: 10.1371/journal.pgen.1010384] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/16/2022] [Accepted: 08/17/2022] [Indexed: 11/29/2022] Open
Abstract
The Ras-like GTPase MglA is a key regulator of front-rear polarity in the rod-shaped Myxococcus xanthus cells. MglA-GTP localizes to the leading cell pole and stimulates assembly of the two machineries for type IV pili-dependent motility and gliding motility. MglA-GTP localization is spatially constrained by its cognate GEF, the RomR/RomX complex, and GAP, the MglB Roadblock-domain protein. Paradoxically, RomR/RomX and MglB localize similarly with low and high concentrations at the leading and lagging poles, respectively. Yet, GEF activity dominates at the leading and GAP activity at the lagging pole by unknown mechanisms. Here, we identify RomY and show that it stimulates MglB GAP activity. The MglB/RomY interaction is low affinity, restricting formation of the bipartite MglB/RomY GAP complex almost exclusively to the lagging pole with the high MglB concentration. Our data support a model wherein RomY, by forming a low-affinity complex with MglB, ensures that the high MglB/RomY GAP activity is confined to the lagging pole where it dominates and outcompetes the GEF activity of the RomR/RomX complex. Thereby, MglA-GTP localization is constrained to the leading pole establishing front-rear polarity. Bacterial cells are spatially highly organized with proteins localizing to distinct subcellular locations. This spatial organization, or cell polarity, is important for many cellular processes including motility. The rod-shaped M. xanthus cells move with defined leading and lagging cell poles. This front-rear polarity is brought about by the polarity module, which consists of the small Ras-like GTPase MglA, its GEF (the RomR/RomX complex) and its GAP (MglB). Specifically, MglA-GTP localizes to the leading pole and stimulates assembly of the motility machineries. MglA-GTP localization, in turn, is spatially constrained by its GEF and GAP. Paradoxically, the RomR/RomX GEF and MglB GAP localize similarly with low and high concentrations at the leading and lagging poles, respectively. Yet, GEF activity dominates at the leading and GAP activity at the lagging pole. Here, we identify RomY and show that it stimulates MglB GAP activity. Interestingly, the MglB/RomY interaction is low affinity. Consequently, MglB/RomY complex formation almost exclusively occurs at the lagging cell pole with the high MglB concentration. Thus, the key to precisely stimulating MglB GAP activity only at the lagging pole is that the MglB/RomY interaction is low-affinity, ultimately restricting MglA-GTP to the leading pole.
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Affiliation(s)
- Dobromir Szadkowski
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- * E-mail:
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15
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Yue S, Li G, He S, Li T. The central role of mTORC1 in amino acid sensing. Cancer Res 2022; 82:2964-2974. [PMID: 35749594 DOI: 10.1158/0008-5472.can-21-4403] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/28/2022] [Accepted: 06/17/2022] [Indexed: 11/16/2022]
Abstract
The mechanistic target of rapamycin (mTOR) is a master regulator of cell growth that controls cell homeostasis in response to nutrients, growth factors, and other environmental cues. Recent studies have emphasized the importance of lysosomes as a hub for nutrient sensing, especially amino acid sensing by mTORC1. This review highlights recent advances in understanding the amino acid-mTORC1 signaling axis and the role of mTORC1 in cancer.
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16
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Egri SB, Ouch C, Chou HT, Yu Z, Song K, Xu C, Shen K. Cryo-EM structures of the human GATOR1-Rag-Ragulator complex reveal a spatial-constraint regulated GAP mechanism. Mol Cell 2022; 82:1836-1849.e5. [PMID: 35338845 PMCID: PMC9133170 DOI: 10.1016/j.molcel.2022.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/09/2021] [Accepted: 02/28/2022] [Indexed: 12/20/2022]
Abstract
mTORC1 controls cellular metabolic processes in response to nutrient availability. Amino acid signals are transmitted to mTORC1 through the Rag GTPases, which are localized on the lysosomal surface by the Ragulator complex. The Rag GTPases receive amino acid signals from multiple upstream regulators. One negative regulator, GATOR1, is a GTPase activating protein (GAP) for RagA. GATOR1 binds to the Rag GTPases via two modes: an inhibitory mode and a GAP mode. How these two binding interactions coordinate to process amino acid signals is unknown. Here, we resolved three cryo-EM structural models of the GATOR1-Rag-Ragulator complex, with the Rag-Ragulator subcomplex occupying the inhibitory site, the GAP site, and both binding sites simultaneously. When the Rag GTPases bind to GATOR1 at the GAP site, both Rag subunits contact GATOR1 to coordinate their nucleotide loading states. These results reveal a potential GAP mechanism of GATOR1 during the mTORC1 inactivation process.
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Affiliation(s)
- Shawn B Egri
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA 01605, USA
| | - Christna Ouch
- Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Chan Medical School, 364 Plantation St, Worcester, MA 01605, USA
| | - Hui-Ting Chou
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Zhiheng Yu
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Kangkang Song
- Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Chan Medical School, 364 Plantation St, Worcester, MA 01605, USA
| | - Chen Xu
- Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Chan Medical School, 364 Plantation St, Worcester, MA 01605, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA 01605, USA.
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17
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Simcox J, Lamming DW. The central moTOR of metabolism. Dev Cell 2022; 57:691-706. [PMID: 35316619 PMCID: PMC9004513 DOI: 10.1016/j.devcel.2022.02.024] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/20/2022] [Accepted: 02/24/2022] [Indexed: 12/21/2022]
Abstract
The protein kinase mechanistic target of rapamycin (mTOR) functions as a central regulator of metabolism, integrating diverse nutritional and hormonal cues to control anabolic processes, organismal physiology, and even aging. This review discusses the current state of knowledge regarding the regulation of mTOR signaling and the metabolic regulation of the four macromolecular building blocks of the cell: carbohydrate, nucleic acid, lipid, and protein by mTOR. We review the role of mTOR in the control of organismal physiology and aging through its action in key tissues and discuss the potential for clinical translation of mTOR inhibition for the treatment and prevention of diseases of aging.
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Affiliation(s)
- Judith Simcox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Dudley W Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
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18
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Jain V, Bose S, Arya AK, Arif T. Lysosomes in Stem Cell Quiescence: A Potential Therapeutic Target in Acute Myeloid Leukemia. Cancers (Basel) 2022; 14:1618. [PMID: 35406389 PMCID: PMC8996909 DOI: 10.3390/cancers14071618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 12/12/2022] Open
Abstract
Lysosomes are cellular organelles that regulate essential biological processes such as cellular homeostasis, development, and aging. They are primarily connected to the degradation/recycling of cellular macromolecules and participate in cellular trafficking, nutritional signaling, energy metabolism, and immune regulation. Therefore, lysosomes connect cellular metabolism and signaling pathways. Lysosome's involvement in the critical biological processes has rekindled clinical interest towards this organelle for treating various diseases, including cancer. Recent research advancements have demonstrated that lysosomes also regulate the maintenance and hemostasis of hematopoietic stem cells (HSCs), which play a critical role in the progression of acute myeloid leukemia (AML) and other types of cancer. Lysosomes regulate both HSCs' metabolic networks and identity transition. AML is a lethal type of blood cancer with a poor prognosis that is particularly associated with aging. Although the genetic landscape of AML has been extensively described, only a few targeted therapies have been produced, warranting the need for further research. This review summarizes the functions and importance of targeting lysosomes in AML, while highlighting the significance of lysosomes in HSCs maintenance.
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Affiliation(s)
- Vaibhav Jain
- Abramson Cancer Center, Department of Medicine, 421 Curie Blvd., Philadelphia, PA 19104, USA;
| | - Swaroop Bose
- Department of Dermatology, Mount Sinai Icahn School of Medicine, New York, NY 10029, USA;
| | - Awadhesh K. Arya
- Department of Anesthesiology, Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Tasleem Arif
- Department of Cell, Developmental, and Regenerative Biology, Mount Sinai Icahn School of Medicine, New York, NY 10029, USA
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19
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Nuciferine protects against high-fat diet-induced hepatic steatosis and insulin resistance via activating TFEB-mediated autophagy–lysosomal pathway. Acta Pharm Sin B 2021; 12:2869-2886. [PMID: 35755273 PMCID: PMC9214335 DOI: 10.1016/j.apsb.2021.12.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/10/2021] [Accepted: 11/17/2021] [Indexed: 12/30/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis and insulin resistance and there are currently no approved drugs for its treatment. Hyperactivation of mTOR complex 1 (mTORC1) and subsequent impairment of the transcription factor EB (TFEB)-mediated autophagy–lysosomal pathway (ALP) are implicated in the development of NAFLD. Accordingly, agents that augment hepatic TFEB transcriptional activity may have therapeutic potential against NAFLD. The objective of this study was to investigate the effects of nuciferine, a major active component from lotus leaf, on NAFLD and its underlying mechanism of action. Here we show that nuciferine activated ALP and alleviated steatosis, insulin resistance in the livers of NAFLD mice and palmitic acid-challenged hepatocytes in a TFEB-dependent manner. Mechanistic investigation revealed that nuciferine interacts with the Ragulator subunit hepatitis B X-interacting protein and impairs the interaction of the Ragulator complex with Rag GTPases, thereby suppressing lysosomal localization and activity of mTORC1, which activates TFEB-mediated ALP and further ameliorates hepatic steatosis and insulin resistance. Our present results indicate that nuciferine may be a potential agent for treating NAFLD and that regulation of the mTORC1–TFEB–ALP axis could represent a novel pharmacological strategy to combat NAFLD.
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20
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Olanzapine leads to nonalcoholic fatty liver disease through the apolipoprotein A5 pathway. Biomed Pharmacother 2021; 141:111803. [PMID: 34146854 DOI: 10.1016/j.biopha.2021.111803] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/17/2021] [Accepted: 06/07/2021] [Indexed: 12/14/2022] Open
Abstract
The antipsychotic drug olanzapine was reported to induce nonalcoholic fatty liver disease (NAFLD), whereas the underlying mechanism remains incompletely understood. This study investigated whether apolipoprotein A5 (apoA5) and sortilin, two interactive factors involved in NAFLD pathogenesis, are implicated in olanzapine-induced NAFLD. In our study, at week 8, olanzapine treatment successfully induced hepatic steatosis in female C57 BL/6 J mice, which was independent of body weight gain. Likewise, olanzapine effectively mediated hepatocyte steatosis in HepG2 cells characterized by substantially elevated intracellular lipid droplets. Increased plasma triglyceride concentration and decreased plasma apoA5 levels were observed in mice treated with 8-week olanzapine. Surprisingly, olanzapine markedly enhanced hepatic apoA5 protein levels in mice, without a significant effect on rodent hepatic ApoA5 mRNA. Our in vitro study showed that olanzapine reduced apoA5 protein levels in the medium and enhanced apoA5 protein levels in hepatocytes, whereas this drug exerted no effect on hepatocyte APOA5 mRNA. By transfecting APOA5 siRNA into HepG2 cells, it was demonstrated that APOA5 knockdown effectively reversed olanzapine-induced hepatocyte steatosis in vitro. In addition, olanzapine drastically increased sortilin mRNA and protein levels in vivo and in vitro. Interestingly, SORT1 knockdown reduced intracellular apoA5 protein levels and increased medium apoA5 protein levels in vitro, without affecting intracellular APOA5 mRNA levels. Furthermore, SORT1 knockdown greatly ameliorated hepatocyte steatosis in vitro. This study provides the first evidence that sortilin inhibits the hepatic apoA5 secretion that is attributable to olanzapine-induced NAFLD, which provides new insight into effective strategies against NAFLD for patients with schizophrenia administered olanzapine.
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21
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Nesterov SV, Yaguzhinsky LS, Podoprigora GI, Nartsissov YR. Amino Acids as Regulators of Cell Metabolism. BIOCHEMISTRY (MOSCOW) 2021; 85:393-408. [PMID: 32569548 DOI: 10.1134/s000629792004001x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In this review, we discuss the principles of regulation and synchronization of metabolic processes in mammalian cells using a two-component model of cell metabolism consisting of a controlling signaling system that regulates major enzymatic cascades and executive metabolic system that directly performs biosynthetic reactions. This approach has allowed us to distinguish two transitional metabolic states (from catabolism to anabolism and vice versa) accompanied by major rearrangements in the signaling system. The signaling system of natural amino acids was selected, because amino acids are involved in both signaling and executive metabolic subsystems of general cell metabolism. We have developed a graphical representation of metabolic events that allowed us to demonstrate the succession of processes occurring in both metabolic subsystems during complete metabolic cycle in a non-dividing cell. An important revealed feature of the amino acid signaling system is that the signaling properties of amino acid are determined not only by their molecular structure, but also by the location within the cell. Four major signaling groups of amino acids have been identified that localize to lysosomes, mitochondria, cytosol, and extracellular space adjacent to the plasma membrane. Although these amino acids groups are similar in the composition, they have different receptors. We also proposed a scheme for the metabolism regulation by amino acids signaling that can serve as a basis for developing more complete spatio-temporal picture of metabolic regulation involving a wide variety of intracellular signaling cascades.
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Affiliation(s)
- S V Nesterov
- Institute of Cytochemistry and Molecular Pharmacology, Moscow, 115404, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - L S Yaguzhinsky
- Institute of Cytochemistry and Molecular Pharmacology, Moscow, 115404, Russia. .,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - G I Podoprigora
- Institute of Cytochemistry and Molecular Pharmacology, Moscow, 115404, Russia
| | - Ya R Nartsissov
- Institute of Cytochemistry and Molecular Pharmacology, Moscow, 115404, Russia
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22
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Kapoor S, Kodesia A, Kalidas N, Ashish, Thakur KG. Structural characterization of Myxococcus xanthus MglC, a component of the polarity control system, and its interactions with its paralog MglB. J Biol Chem 2021; 296:100308. [PMID: 33493516 PMCID: PMC7949163 DOI: 10.1016/j.jbc.2021.100308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 11/28/2022] Open
Abstract
The δ-proteobacteria Myxococcus xanthus displays social (S) and adventurous (A) motilities, which require pole-to-pole reversal of the motility regulator proteins. Mutual gliding motility protein C (MglC), a paralog of GTPase-activating protein Mutual gliding motility protein B (MglB), is a member of the polarity module involved in regulating motility. However, little is known about the structure and function of MglC. Here, we determined ∼1.85 Å resolution crystal structure of MglC using Selenomethionine Single-wavelength anomalous diffraction. The crystal structure revealed that, despite sharing <9% sequence identity, both MglB and MglC adopt a Regulatory Light Chain 7 family fold. However, MglC has a distinct ∼30° to 40° shift in the orientation of the functionally important α2 helix compared with other structural homologs. Using isothermal titration calorimetry and size-exclusion chromatography, we show that MglC binds MglB in 2:4 stoichiometry with submicromolar range dissociation constant. Using small-angle X-ray scattering and molecular docking studies, we show that the MglBC complex consists of a MglC homodimer sandwiched between two homodimers of MglB. A combination of size-exclusion chromatography and site-directed mutagenesis studies confirmed the MglBC interacting interface obtained by molecular docking studies. Finally, we show that the C-terminal region of MglB, crucial for binding its established partner MglA, is not required for binding MglC. These studies suggest that the MglB uses distinct interfaces to bind MglA and MglC. Based on these data, we propose a model suggesting a new role for MglC in polarity reversal in M. xanthus.
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Affiliation(s)
- Srajan Kapoor
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Akriti Kodesia
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Nidhi Kalidas
- Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Ashish
- Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Krishan Gopal Thakur
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India.
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23
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Zhu SY, Yao RQ, Li YX, Zhao PY, Ren C, Du XH, Yao YM. Lysosomal quality control of cell fate: a novel therapeutic target for human diseases. Cell Death Dis 2020; 11:817. [PMID: 32999282 PMCID: PMC7528093 DOI: 10.1038/s41419-020-03032-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/15/2020] [Indexed: 02/08/2023]
Abstract
In eukaryotic cells, lysosomes are digestive centers where biological macromolecules are degraded by phagocytosis and autophagy, thereby maintaining cellular self-renewal capacity and energy supply. Lysosomes also serve as signaling hubs to monitor the intracellular levels of nutrients and energy by acting as platforms for the assembly of multiple signaling pathways, such as mammalian target of rapamycin complex 1 (mTORC1) and adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK). The structural integrity and functional balance of lysosomes are essential for cell function and viability. In fact, lysosomal damage not only disrupts intracellular clearance but also results in the leakage of multiple contents, which pose great threats to the cell by triggering cell death pathways, including apoptosis, necroptosis, pyroptosis, and ferroptosis. The collapse of lysosomal homeostasis is reportedly critical for the pathogenesis and development of various diseases, such as tumors, neurodegenerative diseases, cardiovascular diseases, and inflammatory diseases. Lysosomal quality control (LQC), comprising lysosomal repair, lysophagy, and lysosomal regeneration, is rapidly initiated in response to lysosomal damage to maintain lysosomal structural integrity and functional homeostasis. LQC may be a novel but pivotal target for disease treatment because of its indispensable role in maintaining intracellular homeostasis and cell fate.
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Affiliation(s)
- Sheng-Yu Zhu
- Trauma Research Center, Fourth Medical Center and Medical Innovation Research Division of the Chinese PLA General Hospital, 100048, Beijing, People's Republic of China.,Department of General Surgery, First Medical Center of the Chinese PLA General Hospital, 100853, Beijing, People's Republic of China.,School of Medicine, Nankai University, 300071, Tianjin, People's Republic of China
| | - Ren-Qi Yao
- Trauma Research Center, Fourth Medical Center and Medical Innovation Research Division of the Chinese PLA General Hospital, 100048, Beijing, People's Republic of China.,Department of Burn Surgery, Changhai Hospital, Naval Medical University, 200433, Shanghai, People's Republic of China
| | - Yu-Xuan Li
- Department of General Surgery, First Medical Center of the Chinese PLA General Hospital, 100853, Beijing, People's Republic of China
| | - Peng-Yue Zhao
- Department of General Surgery, First Medical Center of the Chinese PLA General Hospital, 100853, Beijing, People's Republic of China
| | - Chao Ren
- Trauma Research Center, Fourth Medical Center and Medical Innovation Research Division of the Chinese PLA General Hospital, 100048, Beijing, People's Republic of China.
| | - Xiao-Hui Du
- Department of General Surgery, First Medical Center of the Chinese PLA General Hospital, 100853, Beijing, People's Republic of China.
| | - Yong-Ming Yao
- Trauma Research Center, Fourth Medical Center and Medical Innovation Research Division of the Chinese PLA General Hospital, 100048, Beijing, People's Republic of China.
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24
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De Zan E, van Stiphout R, Gapp BV, Blomen VA, Brummelkamp TR, Nijman SMB. Quantitative genetic screening reveals a Ragulator-FLCN feedback loop that regulates the mTORC1 pathway. Sci Signal 2020; 13:13/649/eaba5665. [PMID: 32934076 DOI: 10.1126/scisignal.aba5665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Forward genetic screens in mammalian cell lines, such as RNAi and CRISPR-Cas9 screens, have made major contributions to the elucidation of diverse signaling pathways. Here, we exploited human haploid cells as a robust comparative screening platform and report a set of quantitative forward genetic screens for identifying regulatory mechanisms of mTORC1 signaling, a key growth control pathway that senses diverse metabolic states. Selected chemical and genetic perturbations in this screening platform, including rapamycin treatment and genetic ablation of the Ragulator subunit LAMTOR4, revealed the known core mTORC1 regulatory signaling complexes and the intimate interplay of the mTORC1 pathway with lysosomal function, validating the approach. In addition, we identified a differential requirement for LAMTOR4 and LAMTOR5 in regulating the mTORC1 pathway under fed and starved conditions. Furthermore, we uncovered a previously unknown "synthetic-sick" interaction between the tumor suppressor folliculin and LAMTOR4, which may have therapeutic implications in cancer treatment. Together, our study demonstrates the use of iterative "perturb and observe" genetic screens to uncover regulatory mechanisms driving complex mammalian signaling networks.
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Affiliation(s)
- Erica De Zan
- Ludwig Institute for Cancer Research, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7FZ, UK
| | - Ruud van Stiphout
- Ludwig Institute for Cancer Research, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7FZ, UK
| | - Bianca V Gapp
- Ludwig Institute for Cancer Research, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7FZ, UK
| | | | | | - Sebastian M B Nijman
- Ludwig Institute for Cancer Research, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7FZ, UK.
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25
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Takahara T, Amemiya Y, Sugiyama R, Maki M, Shibata H. Amino acid-dependent control of mTORC1 signaling: a variety of regulatory modes. J Biomed Sci 2020; 27:87. [PMID: 32799865 PMCID: PMC7429791 DOI: 10.1186/s12929-020-00679-2] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/30/2020] [Indexed: 01/10/2023] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is an essential regulator of cell growth and metabolism through the modulation of protein and lipid synthesis, lysosome biogenesis, and autophagy. The activity of mTORC1 is dynamically regulated by several environmental cues, including amino acid availability, growth factors, energy levels, and stresses, to coordinate cellular status with environmental conditions. Dysregulation of mTORC1 activity is closely associated with various diseases, including diabetes, cancer, and neurodegenerative disorders. The discovery of Rag GTPases has greatly expanded our understanding of the regulation of mTORC1 activity by amino acids, especially leucine and arginine. In addition to Rag GTPases, other factors that also contribute to the modulation of mTORC1 activity have been identified. In this review, we discuss the mechanisms of regulation of mTORC1 activity by particular amino acids.
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Affiliation(s)
- Terunao Takahara
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.
| | - Yuna Amemiya
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Risa Sugiyama
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Masatoshi Maki
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Hideki Shibata
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
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26
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Tang Y, Fang G, Guo F, Zhang H, Chen X, An L, Chen M, Zhou L, Wang W, Ye T, Zhou L, Nie P, Yu H, Lin M, Zhao Y, Lin X, Yuan Z, Jiao S, Zhou Z. Selective Inhibition of STRN3-Containing PP2A Phosphatase Restores Hippo Tumor-Suppressor Activity in Gastric Cancer. Cancer Cell 2020; 38:115-128.e9. [PMID: 32589942 DOI: 10.1016/j.ccell.2020.05.019] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/23/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022]
Abstract
Loss of Hippo tumor-suppressor activity and hyperactivation of YAP are commonly observed in cancers. Inactivating mutations of Hippo kinases MST1/2 are uncommon, and it remains unclear how their activity is turned off during tumorigenesis. We identified STRN3 as an essential regulatory subunit of protein phosphatase 2A (PP2A) that recruits MST1/2 and promotes its dephosphorylation, which results in YAP activation. We also identified STRN3 upregulation in gastric cancer correlated with YAP activation and poor prognosis. Based on this mechanistic understanding and aided by structure-guided medicinal chemistry, we developed a highly selective peptide inhibitor, STRN3-derived Hippo-activating peptide, or SHAP, which disrupts the STRN3-PP2Aa interaction and reactivates the Hippo tumor suppressor, inhibits YAP activation, and has antitumor effects in vivo.
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Affiliation(s)
- Yang Tang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Tongji University Cancer Center, Postdoctoral Station of Clinical Medicine, Department of Medical Ultrasound, Ultrasound Research and Education Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Gemin Fang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Fenghua Guo
- Department of General Surgery, Hua'shan Hospital, Fudan University Shanghai Medical College, Shanghai 200040, China
| | - Hui Zhang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaoxu Chen
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Liwei An
- Tongji University Cancer Center, Postdoctoral Station of Clinical Medicine, Department of Medical Ultrasound, Ultrasound Research and Education Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Min Chen
- Tongji University Cancer Center, Postdoctoral Station of Clinical Medicine, Department of Medical Ultrasound, Ultrasound Research and Education Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Li Zhou
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wenjia Wang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Tiantian Ye
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Lei Zhou
- State Key Laboratory of Drug Research and Center of Pharmaceutics, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 201203, China
| | - Pingping Nie
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Haijun Yu
- State Key Laboratory of Drug Research and Center of Pharmaceutics, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 201203, China
| | - Moubin Lin
- Department of General Surgery, Yangpu Hospital, Tongji University School of Medicine, Shanghai 200090, China
| | - Yun Zhao
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xinhua Lin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Zengqiang Yuan
- Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Shi Jiao
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.
| | - Zhaocai Zhou
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China.
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27
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Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to various environmental inputs, especially amino acids. In fact, the activity of mTORC1 is highly sensitive to changes in amino acid levels. Over past decades, a variety of proteins have been identified as participating in the mTORC1 pathway regulated by amino acids. Classically, the Rag guanosine triphosphatases (GTPases), which reside on the lysosome, transmit amino acid availability to the mTORC1 pathway and recruit mTORC1 to the lysosome upon amino acid sufficiency. Recently, several sensors of leucine, arginine, and S-adenosylmethionine for the amino acid-stimulated mTORC1 pathway have been coming to light. Characterization of these sensors is requisite for understanding how cells adjust amino acid sensing pathways to their different needs. In this review, we summarize recent advances in amino acid sensing mechanisms that regulate mTORC1 activity and highlight these identified sensors that accurately transmit specific amino acid signals to the mTORC1 pathway.
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Affiliation(s)
- Xiu-Zhi Li
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan 430070, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.,Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan 430070, China
| | - Xiang-Hua Yan
- State Key Laboratory of Agricultural Microbiology, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan 430070, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China.,Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan 430070, China
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28
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Al-Bari MAA, Xu P. Molecular regulation of autophagy machinery by mTOR-dependent and -independent pathways. Ann N Y Acad Sci 2020; 1467:3-20. [PMID: 31985829 DOI: 10.1111/nyas.14305] [Citation(s) in RCA: 169] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 11/23/2019] [Accepted: 01/07/2020] [Indexed: 12/15/2022]
Abstract
Macroautophagy is a lysosomal degradative pathway or recycling process that maintains cellular homeostasis. This autophagy involves a series of sequential processing events, such as initiation; elongation and nucleation of the isolation membrane; cargo recruitment and maturation of the autophagosome (AP); transport of the AP; docking and fusion of the AP with a late endosome or lysosome; and regeneration of the lysosome by the autophagic lysosomal reformation cycle. These events are critically coordinated by the action of a set of several key components, including autophagy-related proteins (Atg), and regulated by intricate networks, such as mechanistic target of rapamycin (mTOR), a master regulator of autophagy, as well as mTOR-independent signaling pathways. Among mTOR-independent pathways, the transient receptor potential (TRP) calcium ion channel TRPML (mucolipin) subfamily is emerging as an important signaling channel to modulate lysosomal biogenesis and autophagy. This review discusses the recent advances in elucidating the molecular mechanisms and regulation of the autophagy process. Understanding these mechanisms may ultimately allow scientists and clinicians to control this process in order to improve human health.
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Affiliation(s)
| | - Pingyong Xu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Beijing Key Laboratory of Noncoding RNA, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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29
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Shen K, Rogala KB, Chou HT, Huang RK, Yu Z, Sabatini DM. Cryo-EM Structure of the Human FLCN-FNIP2-Rag-Ragulator Complex. Cell 2019; 179:1319-1329.e8. [PMID: 31704029 PMCID: PMC7008705 DOI: 10.1016/j.cell.2019.10.036] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/08/2019] [Accepted: 10/28/2019] [Indexed: 12/22/2022]
Abstract
mTORC1 controls anabolic and catabolic processes in response to nutrients through the Rag GTPase heterodimer, which is regulated by multiple upstream protein complexes. One such regulator, FLCN-FNIP2, is a GTPase activating protein (GAP) for RagC/D, but despite its important role, how it activates the Rag GTPase heterodimer remains unknown. We used cryo-EM to determine the structure of FLCN-FNIP2 in a complex with the Rag GTPases and Ragulator. FLCN-FNIP2 adopts an extended conformation with two pairs of heterodimerized domains. The Longin domains heterodimerize and contact both nucleotide binding domains of the Rag heterodimer, while the DENN domains interact at the distal end of the structure. Biochemical analyses reveal a conserved arginine on FLCN as the catalytic arginine finger and lead us to interpret our structure as an on-pathway intermediate. These data reveal features of a GAP-GTPase interaction and the structure of a critical component of the nutrient-sensing mTORC1 pathway.
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Affiliation(s)
- Kuang Shen
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA; Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, 01605, USA
| | - Kacper B Rogala
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Hui-Ting Chou
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Rick K Huang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Zhiheng Yu
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA.
| | - David M Sabatini
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 455 Main Street, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA.
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30
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Abstract
The mechanistic target of rapamycin (mTOR) signaling pathway coordinates environmental and intracellular cues to control eukaryotic cell growth. As a pivot point between anabolic and catabolic processes, mTOR complex 1 (mTORC1) signaling has established roles in regulating metabolism, translation and autophagy. Hyperactivity of the mTOR pathway is associated with numerous human diseases, including diabetes, cancer and epilepsy. Pharmacological inhibition of the mTOR pathway can extend lifespan in a variety of model organisms. Given its broad control of essential cellular processes and clear relevance to human health, there is extensive interest in elucidating how upstream inputs regulate mTORC1 activation. In this Cell Science at a Glance article and accompanying poster, we summarize our understanding of how extracellular and intracellular signals feed into the mTOR pathway, how the lysosome acts as an mTOR signaling hub, and how downstream signaling controls autophagy and lysosome biogenesis.
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Affiliation(s)
- Kendall J Condon
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Broad Institute, Cambridge, MA 02142, USA.,The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA .,Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Broad Institute, Cambridge, MA 02142, USA.,The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139, USA
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31
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Rogala KB, Gu X, Kedir JF, Abu-Remaileh M, Bianchi LF, Bottino AMS, Dueholm R, Niehaus A, Overwijn D, Fils ACP, Zhou SX, Leary D, Laqtom NN, Brignole EJ, Sabatini DM. Structural basis for the docking of mTORC1 on the lysosomal surface. Science 2019; 366:468-475. [PMID: 31601708 PMCID: PMC7176403 DOI: 10.1126/science.aay0166] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022]
Abstract
The mTORC1 (mechanistic target of rapamycin complex 1) protein kinase regulates growth in response to nutrients and growth factors. Nutrients promote its translocation to the lysosomal surface, where its Raptor subunit interacts with the Rag guanosine triphosphatase (GTPase)-Ragulator complex. Nutrients switch the heterodimeric Rag GTPases among four different nucleotide-binding states, only one of which (RagA/B•GTP-RagC/D•GDP) permits mTORC1 association. We used cryo-electron microscopy to determine the structure of the supercomplex of Raptor with Rag-Ragulator at a resolution of 3.2 angstroms. Our findings indicate that the Raptor α-solenoid directly detects the nucleotide state of RagA while the Raptor "claw" threads between the GTPase domains to detect that of RagC. Mutations that disrupted Rag-Raptor binding inhibited mTORC1 lysosomal localization and signaling. By comparison with a structure of mTORC1 bound to its activator Rheb, we developed a model of active mTORC1 docked on the lysosome.
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Affiliation(s)
- Kacper B Rogala
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xin Gu
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jibril F Kedir
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Monther Abu-Remaileh
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Laura F Bianchi
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | | | - Rikke Dueholm
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Anna Niehaus
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Daan Overwijn
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | | | - Sherry X Zhou
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Daniel Leary
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Nouf N Laqtom
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Edward J Brignole
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- MIT.nano, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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32
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Phosphorylation of DEPDC5, a component of the GATOR1 complex, releases inhibition of mTORC1 and promotes tumor growth. Proc Natl Acad Sci U S A 2019; 116:20505-20510. [PMID: 31548394 DOI: 10.1073/pnas.1904774116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Pim and AKT serine/threonine protein kinases are implicated as drivers of cancer. Their regulation of tumor growth is closely tied to the ability of these enzymes to mainly stimulate protein synthesis by activating mTORC1 (mammalian target of rapamycin complex 1) signaling, although the exact mechanism is not completely understood. mTORC1 activity is normally suppressed by amino acid starvation through a cascade of multiple regulatory protein complexes, e.g., GATOR1, GATOR2, and KICSTOR, that reduce the activity of Rag GTPases. Bioinformatic analysis revealed that DEPDC5 (DEP domain containing protein 5), a component of GATOR1 complex, contains Pim and AKT protein kinase phosphorylation consensus sequences. DEPDC5 phosphorylation by Pim and AKT kinases was confirmed in cancer cells through the use of phospho-specific antibodies and transfection of phospho-inactive DEPDC5 mutants. Consistent with these findings, during amino acid starvation the elevated expression of Pim1 overcame the amino acid inhibitory protein cascade and activated mTORC1. In contrast, the knockout of DEPDC5 partially blocked the ability of small molecule inhibitors against Pim and AKT kinases both singly and in combination to suppress tumor growth and mTORC1 activity in vitro and in vivo. In animal experiments knocking in a glutamic acid (S1530E) in DEPDC5, a phospho mimic, in tumor cells induced a significant level of resistance to Pim and the combination of Pim and AKT inhibitors. Our results indicate a phosphorylation-dependent regulatory mechanism targeting DEPDC5 through which Pim1 and AKT act as upstream effectors of mTORC1 to facilitate proliferation and survival of cancer cells.
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Zhang T, Péli-Gulli MP, Zhang Z, Tang X, Ye J, De Virgilio C, Ding J. Structural insights into the EGO-TC-mediated membrane tethering of the TORC1-regulatory Rag GTPases. SCIENCE ADVANCES 2019; 5:eaax8164. [PMID: 31579828 PMCID: PMC6760929 DOI: 10.1126/sciadv.aax8164] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/26/2019] [Indexed: 06/10/2023]
Abstract
The Rag/Gtr GTPases serve as a central module in the nutrient-sensing signaling network upstream of TORC1. In yeast, the anchoring of Gtr1-Gtr2 to membranes depends on the Ego1-Ego2-Ego3 ternary complex (EGO-TC), resulting in an EGO-TC-Gtr1-Gtr2 complex (EGOC). EGO-TC and human Ragulator share no obvious sequence similarities and also differ in their composition with respect to the number of known subunits, which raises the question of how the EGO-TC fulfills its function in recruiting Gtr1-Gtr2. Here, we report the structure of EGOC, in which Ego1 wraps around Ego2, Ego3, and Gtr1-Gtr2. In addition, Ego3 interacts with Gtr1-Gtr2 to stabilize the complex. The functional roles of key residues involved in the assembly are validated by in vivo assays. Our structural and functional data combined demonstrate that EGOC and Ragulator-Rag complex are structurally conserved and that EGO-TC is essential and sufficient to recruit Gtr1-Gtr2 to membranes to ensure appropriate TORC1 signaling.
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Affiliation(s)
- Tianlong Zhang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | | | - Zhen Zhang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, 393 Hua-Xia Zhong Road, Shanghai 201210, China
| | - Xin Tang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, 393 Hua-Xia Zhong Road, Shanghai 201210, China
| | - Jie Ye
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Jianping Ding
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, 393 Hua-Xia Zhong Road, Shanghai 201210, China
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Rasheed N, Lima TB, Mercaldi GF, Nascimento AF, Silva AL, Righetto GL, Bar‐Peled L, Shen K, Sabatini DM, Gozzo FC, Aparicio R, Smetana JH. C7orf59/LAMTOR4 phosphorylation and structural flexibility modulate Ragulator assembly. FEBS Open Bio 2019; 9:1589-1602. [PMID: 31314152 PMCID: PMC6722880 DOI: 10.1002/2211-5463.12700] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/28/2019] [Accepted: 07/15/2019] [Indexed: 01/09/2023] Open
Abstract
Ragulator is a pentamer composed of p18, MP1, p14, C7orf59, and hepatitis B virus X-interacting protein (HBXIP; LAMTOR 1-5) which acts as a lysosomal scaffold of the Rag GTPases in the amino acid sensitive branch of TORC1 signaling. Here, we present the crystal structure of human HBXIP-C7orf59 dimer (LAMTOR 4/5) at 2.9 Å and identify a phosphorylation site on C7orf59 which modulates its interaction with p18. Additionally, we demonstrate the requirement of HBXIP-C7orf59 to stabilize p18 and allow further binding of MP1-p14. The structure of the dimer revealed an unfolded N terminus in C7orf59 (residues 1-15) which was shown to be essential for p18 binding. Full-length p18 does not interact stably with MP1-p14 in the absence of HBXIP-C7orf59, but deletion of p18 residues 108-161 rescues MP1-p14 binding. C7orf59 was phosphorylated by protein kinase A (PKA) in vitro and mutation of the conserved Ser67 residue to aspartate prevented phosphorylation and negatively affected the C7orf59 interaction with p18 both in cell culture and in vitro. C7orf59 Ser67 was phosphorylated in human embryonic kidney 293T cells. PKA activation with forskolin induced dissociation of p18 from C7orf59, which was prevented by the PKA inhibitor H-89. Our results highlight the essential role of HBXIP-C7orf59 dimer as a nucleator of pentameric Ragulator and support a sequential model of Ragulator assembly in which HBXIP-C7orf59 binds and stabilizes p18 which allows subsequent binding of MP1-p14.
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Affiliation(s)
- Nadia Rasheed
- Brazilian Biosciences National Laboratory (LNBio)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasBrazil
- Institute of BiologyUniversity of CampinasBrazil
| | - Tatiani B. Lima
- Brazilian Biosciences National Laboratory (LNBio)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasBrazil
- Institute of ChemistryUniversity of CampinasBrazil
| | - Gustavo F. Mercaldi
- Brazilian Biosciences National Laboratory (LNBio)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasBrazil
| | - Andrey F.Z. Nascimento
- Brazilian Synchrotron Light Laboratory (LNLS)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasBrazil
| | - Ana L.S. Silva
- Brazilian Biosciences National Laboratory (LNBio)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasBrazil
| | - Germanna L. Righetto
- Brazilian Biosciences National Laboratory (LNBio)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasBrazil
| | | | - Kuang Shen
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMAUSA
- Whitehead Institute for Biomedical ResearchCambridgeMAUSA
- Howard Hughes Medical InstituteCambridgeMAUSA
- Koch Institute for Integrative Cancer ResearchCambridgeMAUSA
- Broad Institute of Harvard and Massachusetts Institute of TechnologyCambridgeMAUSA
| | - David M. Sabatini
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMAUSA
- Whitehead Institute for Biomedical ResearchCambridgeMAUSA
- Howard Hughes Medical InstituteCambridgeMAUSA
- Koch Institute for Integrative Cancer ResearchCambridgeMAUSA
- Broad Institute of Harvard and Massachusetts Institute of TechnologyCambridgeMAUSA
| | | | | | - Juliana H.C. Smetana
- Brazilian Biosciences National Laboratory (LNBio)Brazilian Center for Research in Energy and Materials (CNPEM)CampinasBrazil
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Becker M, Serr I, Salb VK, Ott VB, Mengel L, Blüher M, Weigmann B, Hauner H, Tschöp MH, Daniel C. Short-term cold exposure supports human Treg induction in vivo. Mol Metab 2019; 28:73-82. [PMID: 31427184 PMCID: PMC6822223 DOI: 10.1016/j.molmet.2019.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/22/2019] [Accepted: 08/01/2019] [Indexed: 01/08/2023] Open
Abstract
Objective Obesity and type-2 diabetes (T2D) are metabolic diseases that represent a critical health problem worldwide. Metabolic disease is differentially associated with fat distribution, while visceral white adipose tissue (VAT) is particularly prone to obesity-associated inflammation. Next to their canonical function of immune suppression, regulatory T cells (Tregs) are key in controlling adipose tissue homeostasis. Towards understanding the molecular underpinnings of metabolic disease, we focus on how environmental-metabolic stimuli impinge on the functional interplay between Tregs and adipose tissue. Here, cold exposure or beta3-adrenergic signaling are a promising tool to increase energy expenditure by activating brown adipose tissue, as well as by reducing local inflammation within fat depots by supporting immunosuppressive Tregs. However, in humans, the underlying mechanisms that enable the environmental-immune crosstalk in the periphery and in the respective tissue remain currently unknown. Methods We used combinatorial approaches of next generation humanized mouse models and in vitro and in vivo experiments together with beta3-adrenergic stimulation to dissect the underlying mechanisms of human Treg induction exposed to environmental stimuli such as cold. To test the translational relevance of our findings, we analyzed samples from the FREECE study in which human subjects were exposed to individualized cooling protocols. Samples were analyzed ex vivo and after in vitro Treg induction using qRT-PCR, immunofluorescence, as well as with multicolor flow cytometry and cell sorting. Results In vivo application of the beta3-adrenergic receptor agonist mirabegron in humanized mice induced thermogenesis and improved the Treg induction capacity of naïve T cells isolated from these animals. Using samples from the human FREECE study, we demonstrate that a short-term cold stimulus supports human Treg induction in vitro and in vivo. Mechanistically, we identify BORCS6 encoding the Ragulator-interacting protein C17orf59 to be significantly induced in human CD4+ T cells upon short-term cold exposure. Strong mTOR signaling is known to limit successful Treg induction and thus likely by interfering with mTOR activation at lysosomal surfaces, C17orf59 improves the Treg induction capacity of human naïve T cells upon cold exposure. Conclusions These novel insights into the molecular underpinnings of human Treg induction suggest an important role of Tregs in linking environmental stimuli with adipose tissue function and metabolic diseases. Moreover, these discoveries shed new light on potential approaches towards tailored anti-inflammatory concepts that support human adipose tissue homeostasis by enabling Tregs. Beta3-adrenergic stimulation enhances human Tregs in humanized mice. Short-term cold stimulation increases human Treg induction in vitro and in vivo. Short-term cold exposure elevates human Treg signatures genes. Short-term cold induces BORCS6 encoding C17orf59 in human CD4+T cells. C17orf59 limits mTOR signaling and thereby supports human Treg induction.
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Affiliation(s)
- Maike Becker
- Institute for Diabetes Research, Group Immune Tolerance in Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany; German Center for Diabetes Research (DZD), Munich, Germany
| | - Isabelle Serr
- Institute for Diabetes Research, Group Immune Tolerance in Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany; German Center for Diabetes Research (DZD), Munich, Germany
| | - Victoria K Salb
- Institute for Diabetes Research, Group Immune Tolerance in Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany; German Center for Diabetes Research (DZD), Munich, Germany
| | - Verena B Ott
- Institute for Diabetes Research, Group Immune Tolerance in Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany; German Center for Diabetes Research (DZD), Munich, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Munich-Neuherberg, Germany
| | - Laura Mengel
- ZIEL-Institute for Food & Health, Else Kröner-Fresenius Zentrum für Ernährungsmedizin, Technische Universität München, Freising-Weihenstephan, Germany
| | - Matthias Blüher
- Department of Medicine, University of Leipzig, Leipzig, Germany
| | - Benno Weigmann
- Department of Medicine 1, University of Erlangen-Nuremberg, Kussmaul Campus for Medical Research, Erlangen, Germany
| | - Hans Hauner
- German Center for Diabetes Research (DZD), Munich, Germany; ZIEL-Institute for Food & Health, Else Kröner-Fresenius Zentrum für Ernährungsmedizin, Technische Universität München, Freising-Weihenstephan, Germany; Institute for Nutritional Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Matthias H Tschöp
- German Center for Diabetes Research (DZD), Munich, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Munich-Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Carolin Daniel
- Institute for Diabetes Research, Group Immune Tolerance in Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany; German Center for Diabetes Research (DZD), Munich, Germany; Division of Clinical Pharmacology, Department of Medicine IV, Ludwig-Maximilians-Universität München, Munich, Germany.
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Inpanathan S, Botelho RJ. The Lysosome Signaling Platform: Adapting With the Times. Front Cell Dev Biol 2019; 7:113. [PMID: 31281815 PMCID: PMC6595708 DOI: 10.3389/fcell.2019.00113] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/05/2019] [Indexed: 12/12/2022] Open
Abstract
Lysosomes are the terminal degradative compartment of autophagy, endocytosis and phagocytosis. What once was viewed as a simple acidic organelle in charge of macromolecular digestion has emerged as a dynamic organelle capable of integrating cellular signals and producing signal outputs. In this review, we focus on the concept that the lysosome surface serves as a platform to assemble major signaling hubs like mTORC1, AMPK, GSK3 and the inflammasome. These molecular assemblies integrate and facilitate cross-talk between signals such as amino acid and energy levels, membrane damage and infection, and ultimately enable responses such as autophagy, cell growth, membrane repair and microbe clearance. In particular, we review how molecular machinery like the vacuolar-ATPase proton pump, sestrins, the GATOR complexes, and the Ragulator, modulate mTORC1, AMPK, GSK3 and inflammation. We then elaborate how these signals control autophagy initiation and resolution, TFEB-mediated lysosome adaptation, lysosome remodeling, antigen presentation, inflammation, membrane damage repair and clearance. Overall, by being at the cross-roads for several membrane pathways, lysosomes have emerged as the ideal surveillance compartment to sense, integrate and elicit cellular behavior and adaptation in response to changing environmental and cellular conditions.
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Affiliation(s)
- Subothan Inpanathan
- Department of Chemistry and Biology, Graduate Program in Molecular Science, Ryerson University, Toronto, ON, Canada
| | - Roberto J Botelho
- Department of Chemistry and Biology, Graduate Program in Molecular Science, Ryerson University, Toronto, ON, Canada
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Wang Y, Zhang H. Regulation of Autophagy by mTOR Signaling Pathway. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1206:67-83. [PMID: 31776980 DOI: 10.1007/978-981-15-0602-4_3] [Citation(s) in RCA: 198] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Autophagy plays a crucial role in maintaining cellular homeostasis, and is closely related to the occurrence of variety of human diseases. It is known that autophagy occurs in response to various environmental stresses such as nutrient deficiency, growth factor deficiency, and hypoxia. Induced autophagy eliminates the damage caused by these stresses and returns to normal levels when the stresses are relieved. To comprehend the induction of autophagy under various stress conditions and the effects of autophagy on the life processes of cells, it is necessary to understand how autophagy is regulated. Many studies have shown that a number of signal transduction pathways are involved in the regulation of autophagy. Among these pathways, some pathways converge at the target of rapamycin (TOR), a highly conserved kinase important for autophagy regulation. This review will focus on the role of TOR signaling pathway in the regulation of autophagy.
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Affiliation(s)
- Ying Wang
- Department of Physiology, Chinese Academy of Medical Sciences and Peking Union Medical College, Institute of Basic Medical Sciences, Beijing, China.,Department of Molecular Orthopedics, Beijing Research Institute of Traumatology and Orthopaedics, Beijing, China
| | - Hongbing Zhang
- Department of Physiology, Chinese Academy of Medical Sciences and Peking Union Medical College, Institute of Basic Medical Sciences, Beijing, China.
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38
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Lamming DW, Bar-Peled L. Lysosome: The metabolic signaling hub. Traffic 2019; 20:27-38. [PMID: 30306667 PMCID: PMC6294686 DOI: 10.1111/tra.12617] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/17/2018] [Accepted: 10/07/2018] [Indexed: 12/27/2022]
Abstract
For the past five decades, the lysosome has been characterized as an unglamorous cellular recycling center. This notion has undergone a radical shift in the last 10 years, with new research revealing that this organelle serves as a major hub for metabolic signaling pathways. The discovery that master growth regulators, including the protein kinase mTOR (mechanistic target of rapamycin), make their home at the lysosomal surface has generated intense interest in the lysosome's key role in nutrient sensing and cellular homeostasis. The transcriptional networks required for lysosomal maintenance and function are just being unraveled and their connection to lysosome-based signaling pathways revealed. The catabolic and anabolic pathways that converge on the lysosome connect this organelle with multiple facets of cellular function; when these pathways are deregulated they underlie multiple human diseases, and promote cellular and organismal aging. Thus, understanding how lysosome-based signaling pathways function will not only illuminate the fascinating biology of this organelle but will also be critical in unlocking its therapeutic potentials.
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Affiliation(s)
- Dudley W. Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Liron Bar-Peled
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
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Lawrence RE, Cho KF, Rappold R, Thrun A, Tofaute M, Kim DJ, Moldavski O, Hurley JH, Zoncu R. A nutrient-induced affinity switch controls mTORC1 activation by its Rag GTPase-Ragulator lysosomal scaffold. Nat Cell Biol 2018; 20:1052-1063. [PMID: 30061680 PMCID: PMC6279252 DOI: 10.1038/s41556-018-0148-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 06/20/2018] [Indexed: 12/31/2022]
Abstract
A key step in nutrient sensing is the activation of the master growth regulator, mTORC1 kinase, on the surface of lysosomes. Nutrients enable mTORC1 scaffolding by a complex composed of the Rag GTPases (Rags) and Ragulator, but the underlying mechanism of mTORC1 capture is poorly understood. Combining dynamic imaging in cells and reconstituted systems, we uncover an affinity switch that controls mTORC1 lifetime and activation at the lysosome. Nutrients destabilize the Rag-Ragulator interface, causing cycling of the Rags between lysosome-bound Ragulator and the cytoplasm, and rendering mTORC1 capture contingent on simultaneous engagement of two Rag-binding interfaces. Rag GTPase domains trigger cycling by coordinately weakening binding of the C-terminal domains to Ragulator in a nucleotide-controlled manner. Cancer-specific Rag mutants override release from Ragulator and enhance mTORC1 recruitment and signaling output. Cycling in the active state sets the Rags apart from most signaling GTPases, and provides a mechanism to attenuate mTORC1 signaling.
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Affiliation(s)
- Rosalie E Lawrence
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA
| | - Kelvin F Cho
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA
| | - Ronja Rappold
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA
| | - Anna Thrun
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA
| | - Marie Tofaute
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA
| | - Do Jin Kim
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Ofer Moldavski
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA. .,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA.
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Abstract
Background The protein kinase Target Of Rapamycin (TOR) is a nexus for the regulation of eukaryotic cell growth. TOR assembles into one of two distinct signalling complexes, TOR complex 1 (TORC1) and TORC2 (mTORC1/2 in mammals), with a set of largely non-overlapping protein partners. (m)TORC1 activation occurs in response to a series of stimuli relevant to cell growth, including nutrient availability, growth factor signals and stress, and regulates much of the cell's biosynthetic activity, from proteins to lipids, and recycling through autophagy. mTORC1 regulation is of great therapeutic significance, since in humans many of these signalling complexes, alongside subunits of mTORC1 itself, are implicated in a wide variety of pathophysiologies, including multiple types of cancer, neurological disorders, neurodegenerative diseases and metabolic disorders including diabetes. Methodology Recent years have seen numerous structures determined of (m)TOR, which have provided mechanistic insight into (m)TORC1 activation in particular, however the integration of cellular signals occurs upstream of the kinase and remains incompletely understood. Here we have collected and analysed in detail as many as possible of the molecular and structural studies which have shed light on (m)TORC1 repression, activation and signal integration. Conclusions A molecular understanding of this signal integration pathway is required to understand how (m)TORC1 activation is reconciled with the many diverse and contradictory stimuli affecting cell growth. We discuss the current level of molecular understanding of the upstream components of the (m)TORC1 signalling pathway, recent progress on this key biochemical frontier, and the future studies necessary to establish a mechanistic understanding of this master-switch for eukaryotic cell growth.
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Affiliation(s)
- Kailash Ramlaul
- Section of Structural Biology, Department of Medicine, Imperial College London, SW7 2AZ, UK
| | - Christopher H S Aylett
- Section of Structural Biology, Department of Medicine, Imperial College London, SW7 2AZ, UK
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Meng J, Ferguson SM. GATOR1-dependent recruitment of FLCN-FNIP to lysosomes coordinates Rag GTPase heterodimer nucleotide status in response to amino acids. J Cell Biol 2018; 217:2765-2776. [PMID: 29848618 PMCID: PMC6080935 DOI: 10.1083/jcb.201712177] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 04/29/2018] [Accepted: 05/08/2018] [Indexed: 01/08/2023] Open
Abstract
A large number of lysosome-localized proteins control mTORC1 signaling. Rag guanosine triphosphatase (GTPase) heterodimers play a central role in this pathway by recruiting mTORC1 to lysosomes. Meng and Ferguson reveal how folliculin, a tumor suppressor, coordinates nucleotide states within Rag GTPase heterodimers. Folliculin (FLCN) is a tumor suppressor that coordinates cellular responses to changes in amino acid availability via regulation of the Rag guanosine triphosphatases. FLCN is recruited to lysosomes during amino acid starvation, where it interacts with RagA/B as a heterodimeric complex with FLCN-interacting proteins (FNIPs). The FLCN–FNIP heterodimer also has GTPase-activating protein (GAP) activity toward RagC/D. These properties raised two important questions. First, how is amino acid availability sensed to regulate lysosomal abundance of FLCN? Second, what is the relationship between FLCN lysosome localization, RagA/B interactions, and RagC/D GAP activity? In this study, we show that RagA/B nucleotide status determines the FLCN–FNIP1 recruitment to lysosomes. Starvation-induced FLCN–FNIP lysosome localization requires GAP activity toward Rags 1 (GATOR1), the GAP that converts RagA/B to the guanosine diphosphate (GDP)-bound state. This places FLCN–FNIP recruitment to lysosomes under the control of amino acid sensors that act upstream of GATOR1. By binding to RagA/BGDP and acting on RagC/D, FLCN–FNIP can coordinate nucleotide status between Rag heterodimer subunits in response to changes in amino acid availability.
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Affiliation(s)
- Jin Meng
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Shawn M Ferguson
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT .,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
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Deng Y, Qin Y, Srikantan S, Luo A, Cheng ZM, Flores SK, Vogel KS, Wang E, Dahia PLM. The TMEM127 human tumor suppressor is a component of the mTORC1 lysosomal nutrient-sensing complex. Hum Mol Genet 2018; 27:1794-1808. [PMID: 29547888 PMCID: PMC5932569 DOI: 10.1093/hmg/ddy095] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/07/2018] [Accepted: 03/12/2018] [Indexed: 12/22/2022] Open
Abstract
The TMEM127 tumor suppressor gene encodes a transmembrane protein of unknown function mutated in pheochromocytomas and, rarely, in renal cancers. Tumors with inactivating TMEM127 mutations have increased mTORC1 signaling by undefined mechanisms. Here we report that TMEM127 interacts with the lysosome-anchored complex comprised of Rag GTPases, the LAMTOR pentamer (or 'ragulator') and vATPase, which controls amino acid-mediated mTORC1 activation. We found that under nutrient-rich conditions TMEM127 expression reduces mTORC1 recruitment to Rags. In addition, TMEM127 interacts with LAMTOR in an amino acid-dependent manner and decreases the LAMTOR1-vATPase association, while TMEM127-vATPase binding requires intact lysosomal acidification but is amino acid independent. Conversely, both murine and human cells lacking TMEM127 accumulate LAMTOR proteins in the lysosome. Consistent with these findings, pheochromocytomas with TMEM127 mutations have increased levels of LAMTOR proteins. These results suggest that TMEM127 interactions with ragulator and vATPase at the lysosome contribute to restrain mTORC1 signaling in response to amino acids, thus explaining the increased mTORC1 activation seen in TMEM127-deficient tumors.
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Affiliation(s)
- Yilun Deng
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Department of Cell Systems & Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Yuejuan Qin
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Subramanya Srikantan
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Anqi Luo
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Zi-Ming Cheng
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Shahida K Flores
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Kris S Vogel
- Department of Cell Systems & Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Exing Wang
- Department of Cell Systems & Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Patricia L M Dahia
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Department of Cell Systems & Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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