1
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Sambri I, Ferniani M, Ballabio A. Ragopathies and the rising influence of RagGTPases on human diseases. Nat Commun 2024; 15:5812. [PMID: 38987251 PMCID: PMC11237164 DOI: 10.1038/s41467-024-50034-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 06/27/2024] [Indexed: 07/12/2024] Open
Abstract
RagGTPases (Rags) play an essential role in the regulation of cell metabolism by controlling the activities of both mechanistic target of rapamycin complex 1 (mTORC1) and Transcription factor EB (TFEB). Several diseases, herein named ragopathies, are associated to Rags dysfunction. These diseases may be caused by mutations either in genes encoding the Rags, or in their upstream regulators. The resulting phenotypes may encompass a variety of clinical features such as cataract, kidney tubulopathy, dilated cardiomyopathy and several types of cancer. In this review, we focus on the key clinical, molecular and physio-pathological features of ragopathies, aiming to shed light on their underlying mechanisms.
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Affiliation(s)
- Irene Sambri
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine Program (GEM), Naples, Italy
| | - Marco Ferniani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy.
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2
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Zhang N, Wang X, Feng M, Li M, Wang J, Yang H, He S, Xia Z, Shang L, Jiang X, Sun M, Wu Y, Ren C, Zhang X, Li J, Gao F. Early-life exercise induces immunometabolic epigenetic modification enhancing anti-inflammatory immunity in middle-aged male mice. Nat Commun 2024; 15:3103. [PMID: 38600123 PMCID: PMC11006929 DOI: 10.1038/s41467-024-47458-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 04/03/2024] [Indexed: 04/12/2024] Open
Abstract
Exercise is usually regarded to have short-term beneficial effects on immune health. Here we show that early-life regular exercise exerts long-term beneficial effects on inflammatory immunity. Swimming training for 3 months in male mice starting from 1-month-old curbs cytokine response and mitigates sepsis when exposed to lipopolysaccharide challenge, even after an 11-month interval of detraining. Metabolomics analysis of serum and liver identifies pipecolic acid, a non-encoded amino acid, as a pivotal metabolite responding to early-life regular exercise. Importantly, pipecolic acid reduces inflammatory cytokines in bone marrow-derived macrophages and alleviates sepsis via inhibiting mTOR complex 1 signaling. Moreover, early-life exercise increases histone 3 lysine 4 trimethylation at the promoter of Crym in the liver, an enzyme responsible for catalyzing pipecolic acid production. Liver-specific knockdown of Crym in adult mice abolishes this early exercise-induced protective effects. Our findings demonstrate that early-life regular exercise enhances anti-inflammatory immunity during middle-aged phase in male mice via epigenetic immunometabolic modulation, in which hepatic pipecolic acid production has a pivotal function.
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Affiliation(s)
- Nini Zhang
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
- Department of Pediatrics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Xinpei Wang
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Mengya Feng
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
- Center for Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Min Li
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Jing Wang
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Hongyan Yang
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Siyu He
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Ziqi Xia
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Lei Shang
- Key Laboratory of Hazard Assessment and Control in Special Operational Environment, Ministry of Education; Department of Health Statistics, School of Public Health, Fourth Military Medical University, Xi'an, China
| | - Xun Jiang
- Department of Pediatrics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Mao Sun
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Fourth Military Medical University, Xi'an, China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Fourth Military Medical University, Xi'an, China
| | - Chaoxue Ren
- School of Sport and Health Science, Xi'an Physical Education University, Xi'an, China
| | - Xing Zhang
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Jia Li
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China.
- Key Laboratory of Hazard Assessment and Control in Special Operational Environment, Ministry of Education; Department of Health Statistics, School of Public Health, Fourth Military Medical University, Xi'an, China.
| | - Feng Gao
- Key Laboratory of Aerospace Medicine, Ministry of Education; School of Aerospace Medicine, Fourth Military Medical University, Xi'an, China.
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3
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Iyer H, Shen K, Meireles AM, Talbot WS. A lysosomal regulatory circuit essential for the development and function of microglia. SCIENCE ADVANCES 2022; 8:eabp8321. [PMID: 36044568 PMCID: PMC9432849 DOI: 10.1126/sciadv.abp8321] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/18/2022] [Indexed: 05/17/2023]
Abstract
As the primary phagocytic cells of the central nervous system, microglia exquisitely regulate their lysosomal activity to facilitate brain development and homeostasis. However, mechanisms that coordinate lysosomal activity with microglia development, chemotaxis, and function remain unclear. Here, we show that embryonic macrophages require the lysosomal guanosine triphosphatase (GTPase) RagA and the GTPase-activating protein Folliculin to colonize the brain in zebrafish. We demonstrate that embryonic macrophages in rraga mutants show increased expression of lysosomal genes but display significant down-regulation of immune- and chemotaxis-related genes. Furthermore, we find that RagA and Folliculin repress the key lysosomal transcription factor Tfeb and its homologs Tfe3a and Tfe3b in the macrophage lineage. Using RNA sequencing, we establish that Tfeb and Tfe3 are required for activation of lysosomal target genes under conditions of stress but not for basal expression of lysosomal pathways. Collectively, our data define a lysosomal regulatory circuit essential for macrophage development and function in vivo.
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4
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Gosis BS, Wada S, Thorsheim C, Li K, Jung S, Rhoades JH, Yang Y, Brandimarto J, Li L, Uehara K, Jang C, Lanza M, Sanford NB, Bornstein MR, Jeong S, Titchenell PM, Biddinger SB, Arany Z. Inhibition of nonalcoholic fatty liver disease in mice by selective inhibition of mTORC1. Science 2022; 376:eabf8271. [PMID: 35420934 PMCID: PMC9811404 DOI: 10.1126/science.abf8271] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) remain without effective therapies. The mechanistic target of rapamycin complex 1 (mTORC1) pathway is a potential therapeutic target, but conflicting interpretations have been proposed for how mTORC1 controls lipid homeostasis. We show that selective inhibition of mTORC1 signaling in mice, through deletion of the RagC/D guanosine triphosphatase-activating protein folliculin (FLCN), promotes activation of transcription factor E3 (TFE3) in the liver without affecting other mTORC1 targets and protects against NAFLD and NASH. Disease protection is mediated by TFE3, which both induces lipid consumption and suppresses anabolic lipogenesis. TFE3 inhibits lipogenesis by suppressing proteolytic processing and activation of sterol regulatory element-binding protein-1c (SREBP-1c) and by interacting with SREBP-1c on chromatin. Our data reconcile previously conflicting studies and identify selective inhibition of mTORC1 as a potential approach to treat NASH and NAFLD.
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Affiliation(s)
- Bridget S Gosis
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Shogo Wada
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Chelsea Thorsheim
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kristina Li
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sunhee Jung
- Department of Biological Chemistry, University of California, Irvine, CA, USA
| | - Joshua H Rhoades
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yifan Yang
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeffrey Brandimarto
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Li Li
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kahealani Uehara
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cholsoon Jang
- Department of Biological Chemistry, University of California, Irvine, CA, USA
| | - Matthew Lanza
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nathan B Sanford
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Marc R Bornstein
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sunhye Jeong
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul M Titchenell
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sudha B Biddinger
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Zoltan Arany
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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5
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Folliculin promotes substrate-selective mTORC1 activity by activating RagC to recruit TFE3. PLoS Biol 2022; 20:e3001594. [PMID: 35358174 PMCID: PMC9004751 DOI: 10.1371/journal.pbio.3001594] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/12/2022] [Accepted: 03/07/2022] [Indexed: 12/30/2022] Open
Abstract
Mechanistic target of rapamycin complex I (mTORC1) is central to cellular metabolic regulation. mTORC1 phosphorylates a myriad of substrates, but how different substrate specificity is conferred on mTORC1 by different conditions remains poorly defined. Here, we show how loss of the mTORC1 regulator folliculin (FLCN) renders mTORC1 specifically incompetent to phosphorylate TFE3, a master regulator of lysosome biogenesis, without affecting phosphorylation of other canonical mTORC1 substrates, such as S6 kinase. FLCN is a GTPase-activating protein (GAP) for RagC, a component of the mTORC1 amino acid (AA) sensing pathway, and we show that active RagC is necessary and sufficient to recruit TFE3 onto the lysosomal surface, allowing subsequent phosphorylation of TFE3 by mTORC1. Active mutants of RagC, but not of RagA, rescue both phosphorylation and lysosomal recruitment of TFE3 in the absence of FLCN. These data thus advance the paradigm that mTORC1 substrate specificity is in part conferred by direct recruitment of substrates to the subcellular compartments where mTORC1 resides and identify potential targets for specific modulation of specific branches of the mTOR pathway. How does the mTORC1 complex, which influences myriad cellular processes, achieve specificity? This study shows that substrate specificity is in part conferred by modulating the recruitment of substrates, in this case the transcription factor TFE3, to mTORC1.
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6
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Loss of hepatic Flcn protects against fibrosis and inflammation by activating autophagy pathways. Sci Rep 2021; 11:21268. [PMID: 34711912 PMCID: PMC8553785 DOI: 10.1038/s41598-021-99958-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/24/2021] [Indexed: 11/08/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide and can progress to non-alcoholic steatohepatitis (NASH), which is characterized by triglyceride accumulation, inflammation, and fibrosis. No pharmacological agents are currently approved to treat these conditions, but it is clear now that modulation of lipid synthesis and autophagy are key biological mechanisms that could help reduce or prevent these liver diseases. The folliculin (FLCN) protein has been recently identified as a central regulatory node governing whole body energy homeostasis, and we hypothesized that FLCN regulates highly metabolic tissues like the liver. We thus generated a liver specific Flcn knockout mouse model to study its role in liver disease progression. Using the methionine- and choline-deficient diet to mimic liver fibrosis, we demonstrate that loss of Flcn reduced triglyceride accumulation, fibrosis, and inflammation in mice. In this aggressive liver disease setting, loss of Flcn led to activation of transcription factors TFEB and TFE3 to promote autophagy, promoting the degradation of intracellular lipid stores, ultimately resulting in reduced hepatocellular damage and inflammation. Hence, the activity of FLCN could be a promising target for small molecule drugs to treat liver fibrosis by specifically activating autophagy. Collectively, these results show an unexpected role for Flcn in fatty liver disease progression and highlight new potential treatment strategies.
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7
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Zhuang W, Dong X, Wang B, Liu N, Guo H, Zhang C, Gan W. NRF-1 directly regulates TFE3 and promotes the proliferation of renal cancer cells. Oncol Lett 2021; 22:679. [PMID: 34345304 PMCID: PMC8323008 DOI: 10.3892/ol.2021.12940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 06/07/2021] [Indexed: 11/06/2022] Open
Abstract
The role of transcription factor binding to IGHM enhancer 3 (TFE3) in renal cell carcinoma (RCC) is not well understood. Nuclear respiratory factor 1 (NRF-1) may be the positive upstream regulatory gene of TFE3. The aim of the present study was to determine whether NRF-1 could directly regulate the expression of TFE3 and regulate tumorigenesis and progression of RCC through TFE3. Short hairpin RNA (shRNA) was used to silence the expression of NRF-1 in the 786-O human kidney adenocarcinoma cell line and the 293T human embryonic kidney cell line. Luciferase reporter assays were used to determine the relationship between NRF-1 and TFE3. The CHIP experiment was used to verify the actual binding of NRF-1 and TFE3 promoter regions. MitoTimer staining was used to measure mitochondrial biosynthesis. Flow cytometry was used to detect cell cycle and apoptosis. The 786-O and 293T cells were used to examine the underlying mechanism of action. The results demonstrated that NRF-1 could bind to the promoter region of the TFE3 gene and directly regulate the expression of TFE3. Following NRF-1 knockdown, the protein levels of phosphorylated (p)-AKT and p-S6 of mTOR pathway was inhibited, cell cycle progression was blocked, the levels of apoptosis increased, and mitochondrial generation was reduced. Following overexpression of TFE3, the levels of mTOR-associated markers were restored in NRF-1 knockdown cells. These findings suggest that NRF-1 may regulate the mTOR pathway through TFE3 and regulate the energy metabolism, proliferation and growth of cancer cells by directly regulating the expression of TFE3.
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Affiliation(s)
- Wenyuan Zhuang
- Department of Urology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing University, Nanjing, Jiangsu 210008, P.R. China
| | - Xiang Dong
- Department of Urology, Drum Tower Clinical Medical School of Nanjing Medical University, Nanjing University, Nanjing, Jiangsu 210008, P.R. China
| | - Bo Wang
- Department of Urology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing University, Nanjing, Jiangsu 210008, P.R. China
| | - Ning Liu
- Department of Urology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing University, Nanjing, Jiangsu 210008, P.R. China
| | - Hongqian Guo
- Department of Urology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing University, Nanjing, Jiangsu 210008, P.R. China
| | - Chunni Zhang
- Department of Clinical Laboratory, Jinling Hospital, Nanjing University School of Medicine, Nanjing University, Nanjing, Jiangsu 210008, P.R. China
| | - Weidong Gan
- Department of Urology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing University, Nanjing, Jiangsu 210008, P.R. China
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8
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TSC2 regulates lysosome biogenesis via a non-canonical RAGC and TFEB-dependent mechanism. Nat Commun 2021; 12:4245. [PMID: 34253722 PMCID: PMC8275687 DOI: 10.1038/s41467-021-24499-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 06/11/2021] [Indexed: 02/06/2023] Open
Abstract
Tuberous Sclerosis Complex (TSC) is caused by TSC1 or TSC2 mutations, resulting in hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1). Transcription factor EB (TFEB), a master regulator of lysosome biogenesis, is negatively regulated by mTORC1 through a RAG GTPase-dependent phosphorylation. Here we show that lysosomal biogenesis is increased in TSC-associated renal tumors, pulmonary lymphangioleiomyomatosis, kidneys from Tsc2+/- mice, and TSC1/2-deficient cells via a TFEB-dependent mechanism. Interestingly, in TSC1/2-deficient cells, TFEB is hypo-phosphorylated at mTORC1-dependent sites, indicating that mTORC1 is unable to phosphorylate TFEB in the absence of the TSC1/2 complex. Importantly, overexpression of folliculin (FLCN), a GTPase activating protein for RAGC, increases TFEB phosphorylation at the mTORC1 sites in TSC2-deficient cells. Overexpression of constitutively active RAGC is sufficient to relocalize TFEB to the cytoplasm. These findings establish the TSC proteins as critical regulators of lysosomal biogenesis via TFEB and RAGC and identify TFEB as a driver of the proliferation of TSC2-deficient cells.
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9
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Kim S, Song HS, Yu J, Kim YM. MiT Family Transcriptional Factors in Immune Cell Functions. Mol Cells 2021; 44:342-355. [PMID: 33972476 PMCID: PMC8175148 DOI: 10.14348/molcells.2021.0067] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/01/2021] [Accepted: 04/01/2021] [Indexed: 11/27/2022] Open
Abstract
The microphthalmia-associated transcription factor family (MiT family) proteins are evolutionarily conserved transcription factors that perform many essential biological functions. In mammals, the MiT family consists of MITF (microphthalmia-associated transcription factor or melanocyte-inducing transcription factor), TFEB (transcription factor EB), TFE3 (transcription factor E3), and TFEC (transcription factor EC). These transcriptional factors belong to the basic helix-loop-helix-leucine zipper (bHLH-LZ) transcription factor family and bind the E-box DNA motifs in the promoter regions of target genes to enhance transcription. The best studied functions of MiT proteins include lysosome biogenesis and autophagy induction. In addition, they modulate cellular metabolism, mitochondria dynamics, and various stress responses. The control of nuclear localization via phosphorylation and dephosphorylation serves as the primary regulatory mechanism for MiT family proteins, and several kinases and phosphatases have been identified to directly determine the transcriptional activities of MiT proteins. In different immune cell types, each MiT family member is shown to play distinct or redundant roles and we expect that there is far more to learn about their functions and regulatory mechanisms in host defense and inflammatory responses.
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Affiliation(s)
- Seongryong Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Hyun-Sup Song
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Jihyun Yu
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - You-Me Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- The Center for Epidemic Preparedness, KAIST, Daejeon 34141, Korea
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10
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Ramirez Reyes JMJ, Cuesta R, Pause A. Folliculin: A Regulator of Transcription Through AMPK and mTOR Signaling Pathways. Front Cell Dev Biol 2021; 9:667311. [PMID: 33981707 PMCID: PMC8107286 DOI: 10.3389/fcell.2021.667311] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/29/2021] [Indexed: 12/15/2022] Open
Abstract
Folliculin (FLCN) is a tumor suppressor gene responsible for the inherited Birt-Hogg-Dubé (BHD) syndrome, which affects kidneys, skin and lungs. FLCN is a highly conserved protein that forms a complex with folliculin interacting proteins 1 and 2 (FNIP1/2). Although its sequence does not show homology to known functional domains, structural studies have determined a role of FLCN as a GTPase activating protein (GAP) for small GTPases such as Rag GTPases. FLCN GAP activity on the Rags is required for the recruitment of mTORC1 and the transcriptional factors TFEB and TFE3 on the lysosome, where mTORC1 phosphorylates and inactivates these factors. TFEB/TFE3 are master regulators of lysosomal biogenesis and function, and autophagy. By this mechanism, FLCN/FNIP complex participates in the control of metabolic processes. AMPK, a key regulator of catabolism, interacts with FLCN/FNIP complex. FLCN loss results in constitutive activation of AMPK, which suggests an additional mechanism by which FLCN/FNIP may control metabolism. AMPK regulates the expression and activity of the transcriptional cofactors PGC1α/β, implicated in the control of mitochondrial biogenesis and oxidative metabolism. In this review, we summarize our current knowledge of the interplay between mTORC1, FLCN/FNIP, and AMPK and their implications in the control of cellular homeostasis through the transcriptional activity of TFEB/TFE3 and PGC1α/β. Other pathways and cellular processes regulated by FLCN will be briefly discussed.
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Affiliation(s)
- Josué M. J. Ramirez Reyes
- Goodman Cancer Research Center, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Rafael Cuesta
- Goodman Cancer Research Center, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Arnim Pause
- Goodman Cancer Research Center, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
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11
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La Spina M, Contreras PS, Rissone A, Meena NK, Jeong E, Martina JA. MiT/TFE Family of Transcription Factors: An Evolutionary Perspective. Front Cell Dev Biol 2021; 8:609683. [PMID: 33490073 PMCID: PMC7815692 DOI: 10.3389/fcell.2020.609683] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/24/2020] [Indexed: 12/13/2022] Open
Abstract
Response and adaptation to stress are critical for the survival of all living organisms. The regulation of the transcriptional machinery is an important aspect of these complex processes. The members of the microphthalmia (MiT/TFE) family of transcription factors, apart from their involvement in melanocyte biology, are emerging as key players in a wide range of cellular functions in response to a plethora of internal and external stresses. The MiT/TFE proteins are structurally related and conserved through evolution. Their tissue expression and activities are highly regulated by alternative splicing, promoter usage, and posttranslational modifications. Here, we summarize the functions of MiT/TFE proteins as master transcriptional regulators across evolution and discuss the contribution of animal models to our understanding of the various roles of these transcription factors. We also highlight the importance of deciphering transcriptional regulatory mechanisms in the quest for potential therapeutic targets for human diseases, such as lysosomal storage disorders, neurodegeneration, and cancer.
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Affiliation(s)
- Martina La Spina
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Pablo S Contreras
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Alberto Rissone
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Naresh K Meena
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Eutteum Jeong
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - José A Martina
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
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12
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Irazoqui JE. Key Roles of MiT Transcription Factors in Innate Immunity and Inflammation. Trends Immunol 2020; 41:157-171. [PMID: 31959514 PMCID: PMC6995440 DOI: 10.1016/j.it.2019.12.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 11/26/2019] [Accepted: 12/06/2019] [Indexed: 01/07/2023]
Abstract
Microphthalmia/TFE (MiT) transcription factors (TFs), such as transcription factor EB (TFEB) and transcription factor E3 (TFE3), are emerging as key regulators of innate immunity and inflammation. Rapid progress in the field requires a focused update on the latest advances. Recent studies show that TFEB and TFE3 function in innate immune cells to regulate antibacterial and antiviral responses downstream of phagocytosis, interferon (IFN)-γ, lipopolysaccharide (LPS), and adenosine receptors. Moreover, overexpression of TFEB or TFE3 can drive inflammation in vivo, such as in atherosclerosis, while in other scenarios they can perform anti-inflammatory functions. MiT factors may constitute potential therapeutic targets for a broad range of diseases; however, to harness their therapeutic potential, sophisticated ways to manipulate MiT factor activity safely and effectively must be developed.
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Affiliation(s)
- Javier E Irazoqui
- Department of Microbiology and Physiological Systems and Program in Innate Immunity, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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