1
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Reifenberg P, Zimmer A. Branched-chain amino acids: physico-chemical properties, industrial synthesis and role in signaling, metabolism and energy production. Amino Acids 2024; 56:51. [PMID: 39198298 PMCID: PMC11358235 DOI: 10.1007/s00726-024-03417-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Accepted: 08/20/2024] [Indexed: 09/01/2024]
Abstract
Branched-chain amino acids (BCAAs)-leucine (Leu), isoleucine (Ile), and valine (Val)-are essential nutrients with significant roles in protein synthesis, metabolic regulation, and energy production. This review paper offers a detailed examination of the physico-chemical properties of BCAAs, their industrial synthesis, and their critical functions in various biological processes. The unique isomerism of BCAAs is presented, focusing on analytical challenges in their separation and quantification as well as their solubility characteristics, which are crucial for formulation and purification applications. The industrial synthesis of BCAAs, particularly using bacterial strains like Corynebacterium glutamicum, is explored, alongside methods such as genetic engineering aimed at enhancing production, detailing the enzymatic processes and specific precursors. The dietary uptake, distribution, and catabolism of BCAAs are reviewed as fundamental components of their physiological functions. Ultimately, their multifaceted impact on signaling pathways, immune function, and disease progression is discussed, providing insights into their profound influence on muscle protein synthesis and metabolic health. This comprehensive analysis serves as a resource for understanding both the basic and complex roles of BCAAs in biological systems and their industrial application.
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Affiliation(s)
- Philipp Reifenberg
- Merck Life Science KGaA, Upstream R&D, Frankfurter Strasse 250, 64293, Darmstadt, Germany
- Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Alarich‑Weiss‑Strasse 4, 64287, Darmstadt, Germany
| | - Aline Zimmer
- Merck Life Science KGaA, Upstream R&D, Frankfurter Strasse 250, 64293, Darmstadt, Germany.
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2
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Valenstein ML, Lalgudi PV, Gu X, Kedir JF, Taylor MS, Chivukula RR, Sabatini DM. Rag-Ragulator is the central organizer of the physical architecture of the mTORC1 nutrient-sensing pathway. Proc Natl Acad Sci U S A 2024; 121:e2322755121. [PMID: 39163330 PMCID: PMC11363303 DOI: 10.1073/pnas.2322755121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 07/12/2024] [Indexed: 08/22/2024] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) pathway regulates cell growth and metabolism in response to many environmental cues, including nutrients. Amino acids signal to mTORC1 by modulating the guanine nucleotide loading states of the heterodimeric Rag GTPases, which bind and recruit mTORC1 to the lysosomal surface, its site of activation. The Rag GTPases are tethered to the lysosome by the Ragulator complex and regulated by the GATOR1, GATOR2, and KICSTOR multiprotein complexes that localize to the lysosomal surface through an unknown mechanism(s). Here, we show that mTORC1 is completely insensitive to amino acids in cells lacking the Rag GTPases or the Ragulator component p18. Moreover, not only are the Rag GTPases and Ragulator required for amino acids to regulate mTORC1, they are also essential for the lysosomal recruitment of the GATOR1, GATOR2, and KICSTOR complexes, which stably associate and traffic to the lysosome as the "GATOR" supercomplex. The nucleotide state of RagA/B controls the lysosomal association of GATOR, in a fashion competitively antagonized by the N terminus of the amino acid transporter SLC38A9. Targeting of Ragulator to the surface of mitochondria is sufficient to relocalize the Rags and GATOR to this organelle, but not to enable the nutrient-regulated recruitment of mTORC1 to mitochondria. Thus, our results reveal that the Rag-Ragulator complex is the central organizer of the physical architecture of the mTORC1 nutrient-sensing pathway and underscore that mTORC1 activation requires signal transduction on the lysosomal surface.
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Affiliation(s)
- Max L. Valenstein
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
- Whitehead Institute for Biomedical Research, Cambridge, MA02142
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA02139
- Harvard Medical School, Boston, MA02115
| | - Pranav V. Lalgudi
- Whitehead Institute for Biomedical Research, Cambridge, MA02142
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Xin Gu
- Whitehead Institute for Biomedical Research, Cambridge, MA02142
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA02139
- Harvard Medical School, Boston, MA02115
| | - Jibril F. Kedir
- Whitehead Institute for Biomedical Research, Cambridge, MA02142
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA02139
- Harvard Medical School, Boston, MA02115
| | - Martin S. Taylor
- Harvard Medical School, Boston, MA02115
- Department of Pathology, Massachusetts General Hospital, Boston, MA02114
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI02903
- Brown Center on the Biology of Aging, Brown University, Providence, RI02903
- Legorreta Cancer Center, Brown University, Providence, RI02903
| | - Raghu R. Chivukula
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
- Harvard Medical School, Boston, MA02115
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA02114
- Department of Surgery, Massachusetts General Hospital, Boston, MA02114
- Broad Institute of Harvard and the Massachusetts Institute of Technology, Cambridge, MA02142
| | - David M. Sabatini
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague166 10, Czech Republic
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3
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Ortega-Molina A, Lebrero-Fernández C, Sanz A, Calvo-Rubio M, Deleyto-Seldas N, de Prado-Rivas L, Plata-Gómez AB, Fernández-Florido E, González-García P, Vivas-García Y, Sánchez García E, Graña-Castro O, Price NL, Aroca-Crevillén A, Caleiras E, Monleón D, Borrás C, Casanova-Acebes M, de Cabo R, Efeyan A. A mild increase in nutrient signaling to mTORC1 in mice leads to parenchymal damage, myeloid inflammation and shortened lifespan. NATURE AGING 2024; 4:1102-1120. [PMID: 38849535 PMCID: PMC11333293 DOI: 10.1038/s43587-024-00635-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/25/2024] [Indexed: 06/09/2024]
Abstract
The mechanistic target of rapamycin complex 1 controls cellular anabolism in response to growth factor signaling and to nutrient sufficiency signaled through the Rag GTPases. Inhibition of mTOR reproducibly extends longevity across eukaryotes. Here we report that mice that endogenously express active mutant variants of RagC exhibit multiple features of parenchymal damage that include senescence, expression of inflammatory molecules, increased myeloid inflammation with extensive features of inflammaging and a ~30% reduction in lifespan. Through bone marrow transplantation experiments, we show that myeloid cells are abnormally activated by signals emanating from dysfunctional RagC-mutant parenchyma, causing neutrophil extravasation that inflicts additional inflammatory damage. Therapeutic suppression of myeloid inflammation in aged RagC-mutant mice attenuates parenchymal damage and extends survival. Together, our findings link mildly increased nutrient signaling to limited lifespan in mammals, and support a two-component process of parenchymal damage and myeloid inflammation that together precipitate a time-dependent organ deterioration that limits longevity.
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Affiliation(s)
- Ana Ortega-Molina
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
- Metabolism in cancer and aging Laboratory, Immune System Development And Function Department, Centro de Biología Molecular Severo Ochoa (CBM), Madrid, Spain.
| | - Cristina Lebrero-Fernández
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- Metabolism in cancer and aging Laboratory, Immune System Development And Function Department, Centro de Biología Molecular Severo Ochoa (CBM), Madrid, Spain
| | - Alba Sanz
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Miguel Calvo-Rubio
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Nerea Deleyto-Seldas
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Lucía de Prado-Rivas
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ana Belén Plata-Gómez
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Elena Fernández-Florido
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | - Yurena Vivas-García
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Elena Sánchez García
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Osvaldo Graña-Castro
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- Institute of Applied Molecular Medicine (IMMA-Nemesio Díez), Department of Basic Medical Sciences, School of Medicine, San Pablo-CEU University, CEU Universities, Boadilla del Monte, Madrid, Spain
| | - Nathan L Price
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Alejandra Aroca-Crevillén
- Cardiovascular Regeneration Program, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Eduardo Caleiras
- Histopathology Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Daniel Monleón
- Department of Pathology, University of Valencia, Valencia, Spain; Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable-Instituto de Salud Carlos III (CIBERFES-ISCIII), Institute of Health Research-INCLIVA, Valencia, Spain
| | - Consuelo Borrás
- Freshage Research Group, Department of Physiology, Faculty of Medicine, University of Valencia, Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable-Instituto de Salud Carlos III (CIBERFES-ISCIII), MiniAging Research Group, Institute of Health Research-INCLIVA, Valencia, Spain
| | - María Casanova-Acebes
- Cancer Immunity Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Alejo Efeyan
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
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4
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Wang Y, Guo R, Piedras BI, Tang HY, Asara JM, Tempera I, Lieberman PM, Gewurz BE. The CTLH Ubiquitin Ligase Substrates ZMYND19 and MKLN1 Negatively Regulate mTORC1 at the Lysosomal Membrane. RESEARCH SQUARE 2024:rs.3.rs-4259395. [PMID: 38746323 PMCID: PMC11092817 DOI: 10.21203/rs.3.rs-4259395/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Most Epstein-Barr virus-associated gastric carcinoma (EBVaGC) harbor non-silent mutations that activate phosphoinositide 3 kinase (PI3K) to drive downstream metabolic signaling. To gain insights into PI3K/mTOR pathway dysregulation in this context, we performed a human genome-wide CRISPR/Cas9 screen for hits that synergistically blocked EBVaGC proliferation together with the PI3K antagonist alpelisib. Multiple subunits of carboxy terminal to LisH (CTLH) E3 ligase, including the catalytic MAEA subunit, were among top screen hits. CTLH negatively regulates gluconeogenesis in yeast, but not in higher organisms. Instead, we identified that the CTLH substrates MKLN1 and ZMYND19, which highly accumulated upon MAEA knockout, associated with one another and with lysosomes to inhibit mTORC1. ZMYND19/MKLN1 bound Raptor and RagA/C, but rather than perturbing mTORC1 lysosomal recruitment, instead blocked a late stage of its activation, independently of the tuberous sclerosis complex. Thus, CTLH enables cells to rapidly tune mTORC1 activity at the lysosomal membrane via the ubiquitin/proteasome pathway.
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Affiliation(s)
- Yin Wang
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Rui Guo
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Brenda Iturbide Piedras
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | | | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | | | | | - Benjamin E Gewurz
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Program in Virology, Harvard Medical School
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5
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Abudu YP, Kournoutis A, Brenne HB, Lamark T, Johansen T. MORG1 limits mTORC1 signaling by inhibiting Rag GTPases. Mol Cell 2024; 84:552-569.e11. [PMID: 38103557 DOI: 10.1016/j.molcel.2023.11.023] [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: 11/18/2022] [Revised: 10/02/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023]
Abstract
Autophagy, an important quality control and recycling process vital for cellular homeostasis, is tightly regulated. The mTORC1 signaling pathway regulates autophagy under conditions of nutrient availability and scarcity. However, how mTORC1 activity is fine-tuned during nutrient availability to allow basal autophagy is unclear. Here, we report that the WD-domain repeat protein MORG1 facilitates basal constitutive autophagy by inhibiting mTORC1 signaling through Rag GTPases. Mechanistically, MORG1 interacts with active Rag GTPase complex inhibiting the Rag GTPase-mediated recruitment of mTORC1 to the lysosome. MORG1 depletion in HeLa cells increases mTORC1 activity and decreases autophagy. The autophagy receptor p62/SQSTM1 binds to MORG1, but MORG1 is not an autophagy substrate. However, p62/SQSTM1 binding to MORG1 upon re-addition of amino acids following amino acid's depletion precludes MORG1 from inhibiting the Rag GTPases, allowing mTORC1 activation. MORG1 depletion increases cell proliferation and migration. Low expression of MORG1 correlates with poor survival in several important cancers.
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Affiliation(s)
- Yakubu Princely Abudu
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway; Nanoscopy Group, Department of Physics and Technology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway.
| | - Athanasios Kournoutis
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Hanne Britt Brenne
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Trond Lamark
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Terje Johansen
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway.
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6
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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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7
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Goul C, Peruzzo R, Zoncu R. The molecular basis of nutrient sensing and signalling by mTORC1 in metabolism regulation and disease. Nat Rev Mol Cell Biol 2023; 24:857-875. [PMID: 37612414 DOI: 10.1038/s41580-023-00641-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2023] [Indexed: 08/25/2023]
Abstract
The Ser/Thr kinase mechanistic target of rapamycin (mTOR) is a central regulator of cellular metabolism. As part of mTOR complex 1 (mTORC1), mTOR integrates signals such as the levels of nutrients, growth factors, energy sources and oxygen, and triggers responses that either boost anabolism or suppress catabolism. mTORC1 signalling has wide-ranging consequences for the growth and homeostasis of key tissues and organs, and its dysregulated activity promotes cancer, type 2 diabetes, neurodegeneration and other age-related disorders. How mTORC1 integrates numerous upstream cues and translates them into specific downstream responses is an outstanding question with major implications for our understanding of physiology and disease mechanisms. In this Review, we discuss recent structural and functional insights into the molecular architecture of mTORC1 and its lysosomal partners, which have greatly increased our mechanistic understanding of nutrient-dependent mTORC1 regulation. We also discuss the emerging involvement of aberrant nutrient-mTORC1 signalling in multiple diseases.
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Affiliation(s)
- Claire Goul
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Roberta Peruzzo
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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8
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Priya A, Antoine-Bally S, Macé AS, Monteiro P, Sabatet V, Remy D, Dingli F, Loew D, Demetriades C, Gautreau AM, Chavrier P. Codependencies of mTORC1 signaling and endolysosomal actin structures. SCIENCE ADVANCES 2023; 9:eadd9084. [PMID: 37703363 PMCID: PMC10881074 DOI: 10.1126/sciadv.add9084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/11/2023] [Indexed: 09/15/2023]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is part of the amino acid sensing machinery that becomes activated on the endolysosomal surface in response to nutrient cues. Branched actin generated by WASH and Arp2/3 complexes defines endolysosomal microdomains. Here, we find mTORC1 components in close proximity to endolysosomal actin microdomains. We investigated for interactors of the mTORC1 lysosomal tether, RAGC, by proteomics and identified multiple actin filament capping proteins and their modulators. Perturbation of RAGC function affected the size of endolysosomal actin, consistent with a regulation of actin filament capping by RAGC. Reciprocally, the pharmacological inhibition of actin polymerization or alteration of endolysosomal actin obtained upon silencing of WASH or Arp2/3 complexes impaired mTORC1 activity. Mechanistically, we show that actin is required for proper association of RAGC and mTOR with endolysosomes. This study reveals an unprecedented interplay between actin and mTORC1 signaling on the endolysosomal system.
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Affiliation(s)
- Amulya Priya
- Institut Curie, CNRS UMR144, PSL Research University, Research Center, Actin and Membrane Dynamics Laboratory, 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - Sandra Antoine-Bally
- Institut Curie, CNRS UMR144, PSL Research University, Research Center, Actin and Membrane Dynamics Laboratory, 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - Anne-Sophie Macé
- Institut Curie, PSL Research University, Cell and Tissue Imaging Facility (PICT-IBiSA), 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - Pedro Monteiro
- Institut Curie, CNRS UMR144, PSL Research University, Research Center, Actin and Membrane Dynamics Laboratory, 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - Valentin Sabatet
- Institut Curie, PSL Research University, CurieCoreTech Mass Spectrometry Proteomics, 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - David Remy
- Institut Curie, CNRS UMR144, PSL Research University, Research Center, Actin and Membrane Dynamics Laboratory, 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - Florent Dingli
- Institut Curie, PSL Research University, CurieCoreTech Mass Spectrometry Proteomics, 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - Damarys Loew
- Institut Curie, PSL Research University, CurieCoreTech Mass Spectrometry Proteomics, 26 rue d’Ulm, Paris 75248 Cedex 05, France
| | - Constantinos Demetriades
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Alexis M. Gautreau
- Laboratoire de Biologie Structurale de la Cellule, CNRS, École Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| | - Philippe Chavrier
- Institut Curie, CNRS UMR144, PSL Research University, Research Center, Actin and Membrane Dynamics Laboratory, 26 rue d’Ulm, Paris 75248 Cedex 05, France
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9
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Tettoni SD, Egri SB, Doxsey DD, Veinotte K, Ouch C, Chang JY, Song K, Xu C, Shen K. Structure of the Schizosaccharomyces pombe Gtr-Lam complex reveals evolutionary divergence of mTORC1-dependent amino acid sensing. Structure 2023; 31:1065-1076.e5. [PMID: 37453417 PMCID: PMC10529327 DOI: 10.1016/j.str.2023.06.012] [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: 03/02/2023] [Revised: 05/14/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
mTORC1 is a protein kinase complex that controls cellular growth in response to nutrient availability. Amino acid signals are transmitted toward mTORC1 via the Rag/Gtr GTPases and their upstream regulators. An important regulator is LAMTOR, which localizes Rag/Gtr on the lysosomal/vacuole membrane. In human cells, LAMTOR consists of five subunits, but in yeast, only three or four. Currently, it is not known how variation of the subunit stoichiometry may affect its structural organization and biochemical properties. Here, we report a 3.1 Å-resolution structural model of the Gtr-Lam complex in Schizosaccharomyces pombe. We found that SpGtr shares conserved architecture as HsRag, but the intersubunit communication that coordinates nucleotide loading on the two subunits differs. In contrast, SpLam contains distinctive structural features, but its GTP-specific GEF activity toward SpGtr is evolutionarily conserved. Our results revealed unique evolutionary paths of the protein components of the mTORC1 pathway.
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Affiliation(s)
- Steven D Tettoni
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Shawn B Egri
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Dylan D Doxsey
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Kristen Veinotte
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Christna Ouch
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Jeng-Yih Chang
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Kangkang Song
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Chen Xu
- Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation Street, Worcester, MA 01605, USA; Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
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10
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Titze S, Kümmel D. The difference is in the details: Structural and mechanistic variations in the LAMTOR-Gtr/Rag module. Structure 2023; 31:1010-1012. [PMID: 37683616 DOI: 10.1016/j.str.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/04/2023] [Accepted: 08/04/2023] [Indexed: 09/10/2023]
Abstract
In this issue of Structure, Tettoni et al. present the structure and biochemical characterization of the fission yeast LAMTOR-Gtr complex, which mediates nutrient-dependent control of cell growth. The study reveals specific differences to the homologous human LAMTOR-Rag complex that might represent means of evolutionary adaptation.
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Affiliation(s)
- Sonja Titze
- Institute of Biochemistry, University of Münster, 48149 Münster, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, 48149 Münster, Germany.
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11
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Seidel M, Rajkumar S, Steffke C, Noeth V, Agarwal S, Roger K, Lipecka J, Ludolph A, Guerrera CI, Boeckers T, Catanese A. Propranolol reduces the accumulation of cytotoxic aggregates in C9orf72-ALS/FTD in vitro models. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 5:100105. [PMID: 37576491 PMCID: PMC10412779 DOI: 10.1016/j.crneur.2023.100105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/23/2023] [Accepted: 07/26/2023] [Indexed: 08/15/2023] Open
Abstract
Mutations in the C9orf72 gene are the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The pathogenetic mechanisms linked to this gene are a direct consequence of an aberrant intronic expansion of a GGGGCC hexanucleotide located between the 1a and 1b non-coding exons, which can be transcribed to form cytotoxic RNA foci or even translated into aggregation-prone dipeptide repeat proteins. Importantly, the abnormal length of these repeats affects also the expression levels of C9orf72 itself, which suggests haploinsufficiency as additional pathomechanism. Thus, it appears that both toxic gain of function and loss of function are distinct but still coexistent features contributing to the insurgence of the disease in case of C9orf72 mutations. In this study, we aimed at identifying a strategy to address both aspects of the C9orf72-related pathobiochemistry and provide proof-of-principle information for a better understanding of the mechanisms leading to neuronal loss. By using primary neurons overexpressing toxic poly(GA), the most abundant protein product of the GGGGCC repeats, we found that the antiarrhythmic drug propranolol could efficiently reduce the accumulation of aberrant aggregates and increase the survival of C9orf72-related cultures. Interestingly, the improved catabolism appeared to not depend on major degradative pathways such as autophagy and the proteasome. By analyzing the proteome of poly(GA)-expressing neurons after exposure to propranolol, we found that the drug increased lysosomal degradation through a mechanism directly involving C9orf72 protein, whose levels were increased after treatment. Further confirmation of the beneficial effect of the beta blocker on aggregates' accumulation and survival of hiPSC-derived C9orf72-mutant motoneurons strengthened the finding that addressing both facets of C9orf72 pathology might represent a valid strategy for the treatment of these ALS/FTD cases.
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Affiliation(s)
- Mira Seidel
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, Ulm, Germany
| | - Sandeep Rajkumar
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, Ulm, Germany
| | - Christina Steffke
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, Ulm, Germany
| | - Vivien Noeth
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, Ulm, Germany
- International Graduate School in Molecular Medicine, Ulm University, Ulm, Germany
| | - Shreya Agarwal
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, Ulm, Germany
- International Graduate School in Molecular Medicine, Ulm University, Ulm, Germany
| | - Kevin Roger
- Proteomics Platform Necker, Université Paris Cité - Structure Fédérative de Recherche Necker, INSERM US24/CNRS UAR3633, Paris, France
| | - Joanna Lipecka
- Proteomics Platform Necker, Université Paris Cité - Structure Fédérative de Recherche Necker, INSERM US24/CNRS UAR3633, Paris, France
| | - Albert Ludolph
- Department of Neurology, Ulm University School of Medicine, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm site, Ulm, Germany
| | - Chiara Ida Guerrera
- Proteomics Platform Necker, Université Paris Cité - Structure Fédérative de Recherche Necker, INSERM US24/CNRS UAR3633, Paris, France
| | - Tobias Boeckers
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm site, Ulm, Germany
| | - Alberto Catanese
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm site, Ulm, Germany
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12
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Doxsey DD, Tettoni SD, Egri SB, Shen K. Redundant electrostatic interactions between GATOR1 and the Rag GTPase heterodimer drive efficient amino acid sensing in human cells. J Biol Chem 2023; 299:104880. [PMID: 37269949 PMCID: PMC10316081 DOI: 10.1016/j.jbc.2023.104880] [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: 04/10/2023] [Revised: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 06/05/2023] Open
Abstract
Cells need to coordinate nutrient availability with their growth and proliferation. In eukaryotic cells, this coordination is mediated by the mechanistic target of the rapamycin complex 1 (mTORC1) pathway. mTORC1 activation is regulated by two GTPase units, the Rag GTPase heterodimer and the Rheb GTPase. The RagA-RagC heterodimer controls the subcellular localization of mTORC1, and its nucleotide loading states are strictly controlled by upstream regulators including amino acid sensors. A critical negative regulator of the Rag GTPase heterodimer is GATOR1. In the absence of amino acids, GATOR1 stimulates GTP hydrolysis by the RagA subunit to turn off mTORC1 signaling. Despite the enzymatic specificity of GATOR1 to RagA, a recent cryo-EM structural model of the human GATOR1-Rag-Ragulator complex reveals an unexpected interface between Depdc5, a subunit of GATOR1, and RagC. Currently, there is no functional characterization of this interface, nor do we know its biological relevance. Here, combining structure-function analysis, enzymatic kinetic measurements, and cell-based signaling assays, we identified a critical electrostatic interaction between Depdc5 and RagC. This interaction is mediated by the positively charged Arg-1407 residue on Depdc5 and a patch of negatively charged residues on the lateral side of RagC. Abrogating this interaction impairs the GAP activity of GATOR1 and cellular response to amino acid withdrawal. Our results reveal how GATOR1 coordinates the nucleotide loading states of the Rag GTPase heterodimer, and thus precisely controls cellular behavior in the absence of amino acids.
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Affiliation(s)
- Dylan D Doxsey
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Steven D Tettoni
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Shawn B Egri
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA; Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA.
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13
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Sambri I, Ferniani M, Campostrini G, Testa M, Meraviglia V, de Araujo MEG, Dokládal L, Vilardo C, Monfregola J, Zampelli N, Vecchio Blanco FD, Torella A, Ruosi C, Fecarotta S, Parenti G, Staiano L, Bellin M, Huber LA, De Virgilio C, Trepiccione F, Nigro V, Ballabio A. RagD auto-activating mutations impair MiT/TFE activity in kidney tubulopathy and cardiomyopathy syndrome. Nat Commun 2023; 14:2775. [PMID: 37188688 DOI: 10.1038/s41467-023-38428-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 05/03/2023] [Indexed: 05/17/2023] Open
Abstract
Heterozygous mutations in the gene encoding RagD GTPase were shown to cause a novel autosomal dominant condition characterized by kidney tubulopathy and cardiomyopathy. We previously demonstrated that RagD, and its paralogue RagC, mediate a non-canonical mTORC1 signaling pathway that inhibits the activity of TFEB and TFE3, transcription factors of the MiT/TFE family and master regulators of lysosomal biogenesis and autophagy. Here we show that RagD mutations causing kidney tubulopathy and cardiomyopathy are "auto- activating", even in the absence of Folliculin, the GAP responsible for RagC/D activation, and cause constitutive phosphorylation of TFEB and TFE3 by mTORC1, without affecting the phosphorylation of "canonical" mTORC1 substrates, such as S6K. By using HeLa and HK-2 cell lines, human induced pluripotent stem cell-derived cardiomyocytes and patient-derived primary fibroblasts, we show that RRAGD auto-activating mutations lead to inhibition of TFEB and TFE3 nuclear translocation and transcriptional activity, which impairs the response to lysosomal and mitochondrial injury. These data suggest that inhibition of MiT/TFE factors plays a key role in kidney tubulopathy and cardiomyopathy syndrome.
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Affiliation(s)
- Irene Sambri
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy
| | - Marco Ferniani
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy
| | | | - Marialuisa Testa
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
| | | | - Mariana E G de Araujo
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Ladislav Dokládal
- Department of Biology, University of Fribourg, CH-1700, Fribourg, Switzerland
| | - Claudia Vilardo
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
| | - Jlenia Monfregola
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
| | - Nicolina Zampelli
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
| | | | - Annalaura Torella
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Carolina Ruosi
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Simona Fecarotta
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy
| | - Giancarlo Parenti
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy
| | - Leopoldo Staiano
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Institute for Genetic and Biomedical Research, National Research Council (CNR), Milan, Italy
| | - Milena Bellin
- Leiden University Medical Center, 2333ZC, Leiden, the Netherlands
- Department of Biology, University of Padua, 35131, Padua, Italy
- Veneto Institute of Molecular Medicine, 35129, Padua, Italy
| | - Lukas A Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, CH-1700, Fribourg, Switzerland
| | - Francesco Trepiccione
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
- Biogem Research Institute Ariano Irpino, Ariano Irpino, Italy
| | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, (NA), Italy.
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
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14
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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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15
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Jansen RM, Hurley JH. Longin domain GAP complexes in nutrient signalling, membrane traffic and neurodegeneration. FEBS Lett 2023; 597:750-761. [PMID: 36367440 PMCID: PMC10050129 DOI: 10.1002/1873-3468.14538] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
Small GTPases act as molecular switches and control numerous cellular processes by their binding and hydrolysis of guanosine triphosphate (GTP). The activity of small GTPases is coordinated by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). Recent structural and functional studies have characterized a subset of GAPs whose catalytic units consist of longin domains. Longin domain containing GAPs regulate small GTPases that facilitate nutrient signalling, autophagy, vesicular trafficking and lysosome homeostasis. All known examples in this GAP family function as part of larger multiprotein complexes. The three characterized mammalian protein complexes in this class are FLCN:FNIP, GATOR1 and C9orf72:SMCR8. Each complex carries out a unique cellular function by regulating distinct small GTPases. In this article, we explore the roles of longin domain GAPs in nutrient sensing, membrane dynamic, vesicular trafficking and disease. Through a structural lens, we examine the mechanism of each longin domain GAP and highlight potential therapeutic applications.
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Affiliation(s)
- Rachel M. Jansen
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - James H. Hurley
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
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16
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Abstract
Mg2+ is essential for many cellular and physiological processes, including muscle contraction, neuronal activity, and metabolism. Consequently, the blood Mg2+ concentration is tightly regulated by balanced intestinal Mg2+ absorption, renal Mg2+ excretion, and Mg2+ storage in bone and soft tissues. In recent years, the development of novel transgenic animal models and identification of Mendelian disorders has advanced our current insight in the molecular mechanisms of Mg2+ reabsorption in the kidney. In the proximal tubule, Mg2+ reabsorption is dependent on paracellular permeability by claudin-2/12. In the thick ascending limb of Henle's loop, the claudin-16/19 complex provides a cation-selective pore for paracellular Mg2+ reabsorption. The paracellular Mg2+ reabsorption in this segment is regulated by the Ca2+-sensing receptor, parathyroid hormone, and mechanistic target of rapamycin (mTOR) signaling. In the distal convoluted tubule, the fine tuning of Mg2+ reabsorption takes place by transcellular Mg2+ reabsorption via transient receptor potential melastatin-like types 6 and 7 (TRPM6/TRPM7) divalent cation channels. Activity of TRPM6/TRPM7 is dependent on hormonal regulation, metabolic activity, and interacting proteins. Basolateral Mg2+ extrusion is still poorly understood but is probably dependent on the Na+ gradient. Cyclin M2 and SLC41A3 are the main candidates to act as Na+/Mg2+ exchangers. Consequently, disturbances of basolateral Na+/K+ transport indirectly result in impaired renal Mg2+ reabsorption in the distal convoluted tubule. Altogether, this review aims to provide an overview of the molecular mechanisms of Mg2+ reabsorption in the kidney, specifically focusing on transgenic mouse models and human hereditary diseases.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
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17
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Prouteau M, Bourgoint C, Felix J, Bonadei L, Sadian Y, Gabus C, Savvides SN, Gutsche I, Desfosses A, Loewith R. EGOC inhibits TOROID polymerization by structurally activating TORC1. Nat Struct Mol Biol 2023; 30:273-285. [PMID: 36702972 PMCID: PMC10023571 DOI: 10.1038/s41594-022-00912-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 11/21/2022] [Indexed: 01/27/2023]
Abstract
Target of rapamycin complex 1 (TORC1) is a protein kinase controlling cell homeostasis and growth in response to nutrients and stresses. In Saccharomyces cerevisiae, glucose depletion triggers a redistribution of TORC1 from a dispersed localization over the vacuole surface into a large, inactive condensate called TOROID (TORC1 organized in inhibited domains). However, the mechanisms governing this transition have been unclear. Here, we show that acute depletion and repletion of EGO complex (EGOC) activity is sufficient to control TOROID distribution, independently of other nutrient-signaling pathways. The 3.9-Å-resolution structure of TORC1 from TOROID cryo-EM data together with interrogation of key interactions in vivo provide structural insights into TORC1-TORC1' and TORC1-EGOC interaction interfaces. These data support a model in which glucose-dependent activation of EGOC triggers binding to TORC1 at an interface required for TOROID assembly, preventing TORC1 polymerization and promoting release of active TORC1.
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Affiliation(s)
- Manoël Prouteau
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
| | - Clélia Bourgoint
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Jan Felix
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium.
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium.
| | - Lenny Bonadei
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Yashar Sadian
- CryoGEnic facility (DCI Geneva), University of Geneva, Geneva, Switzerland
| | - Caroline Gabus
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Savvas N Savvides
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Unit for Structural Biology, VIB-UGent Center for Inflammation Research, Ghent, Belgium
| | - Irina Gutsche
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Ambroise Desfosses
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Robbie Loewith
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
- Swiss National Centre for Competence in Research Chemical Biology, Geneva, Switzerland.
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18
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New Insights into the Regulation of mTOR Signaling via Ca 2+-Binding Proteins. Int J Mol Sci 2023; 24:ijms24043923. [PMID: 36835331 PMCID: PMC9959742 DOI: 10.3390/ijms24043923] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Environmental factors are important regulators of cell growth and proliferation. Mechanistic target of rapamycin (mTOR) is a central kinase that maintains cellular homeostasis in response to a variety of extracellular and intracellular inputs. Dysregulation of mTOR signaling is associated with many diseases, including diabetes and cancer. Calcium ion (Ca2+) is important as a second messenger in various biological processes, and its intracellular concentration is tightly regulated. Although the involvement of Ca2+ mobilization in mTOR signaling has been reported, the detailed molecular mechanisms by which mTOR signaling is regulated are not fully understood. The link between Ca2+ homeostasis and mTOR activation in pathological hypertrophy has heightened the importance in understanding Ca2+-regulated mTOR signaling as a key mechanism of mTOR regulation. In this review, we introduce recent findings on the molecular mechanisms of regulation of mTOR signaling by Ca2+-binding proteins, particularly calmodulin (CaM).
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19
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Caligaris M, Nicastro R, Hu Z, Tripodi F, Hummel JE, Pillet B, Deprez MA, Winderickx J, Rospert S, Coccetti P, Dengjel J, De Virgilio C. Snf1/AMPK fine-tunes TORC1 signaling in response to glucose starvation. eLife 2023; 12:84319. [PMID: 36749016 PMCID: PMC9937656 DOI: 10.7554/elife.84319] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/06/2023] [Indexed: 02/08/2023] Open
Abstract
The AMP-activated protein kinase (AMPK) and the target of rapamycin complex 1 (TORC1) are central kinase modules of two opposing signaling pathways that control eukaryotic cell growth and metabolism in response to the availability of energy and nutrients. Accordingly, energy depletion activates AMPK to inhibit growth, while nutrients and high energy levels activate TORC1 to promote growth. Both in mammals and lower eukaryotes such as yeast, the AMPK and TORC1 pathways are wired to each other at different levels, which ensures homeostatic control of growth and metabolism. In this context, a previous study (Hughes Hallett et al., 2015) reported that AMPK in yeast, that is Snf1, prevents the transient TORC1 reactivation during the early phase following acute glucose starvation, but the underlying mechanism has remained elusive. Using a combination of unbiased mass spectrometry (MS)-based phosphoproteomics, genetic, biochemical, and physiological experiments, we show here that Snf1 temporally maintains TORC1 inactive in glucose-starved cells primarily through the TORC1-regulatory protein Pib2. Our data, therefore, extend the function of Pib2 to a hub that integrates both glucose and, as reported earlier, glutamine signals to control TORC1. We further demonstrate that Snf1 phosphorylates the TORC1 effector kinase Sch9 within its N-terminal region and thereby antagonizes the phosphorylation of a C-terminal TORC1-target residue within Sch9 itself that is critical for its activity. The consequences of Snf1-mediated phosphorylation of Pib2 and Sch9 are physiologically additive and sufficient to explain the role of Snf1 in short-term inhibition of TORC1 in acutely glucose-starved cells.
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Affiliation(s)
- Marco Caligaris
- Department of Biology, University of FribourgFribourgSwitzerland
| | | | - Zehan Hu
- Department of Biology, University of FribourgFribourgSwitzerland
| | - Farida Tripodi
- Department of Biotechnology and Biosciences, University of Milano-BicoccaMilanoItaly
| | - Johannes Erwin Hummel
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of FreiburgFreiburgGermany
| | - Benjamin Pillet
- Department of Biology, University of FribourgFribourgSwitzerland
| | | | | | - Sabine Rospert
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of FreiburgFreiburgGermany,Signalling Research Centres BIOSS and CIBSS, University of FreiburgFreiburgGermany
| | - Paola Coccetti
- Department of Biotechnology and Biosciences, University of Milano-BicoccaMilanoItaly
| | - Jörn Dengjel
- Department of Biology, University of FribourgFribourgSwitzerland
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20
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Morales J, Allegakoen DV, Garcia JA, Kwong K, Sahu PK, Fajardo DA, Pan Y, Horlbeck MA, Weissman JS, Gustafson WC, Bivona TG, Sabnis AJ. GATOR2-dependent mTORC1 activity is a therapeutic vulnerability in FOXO1 fusion-positive rhabdomyosarcoma. JCI Insight 2022; 7:e162207. [PMID: 36282590 PMCID: PMC9746907 DOI: 10.1172/jci.insight.162207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/18/2022] [Indexed: 01/12/2023] Open
Abstract
Oncogenic FOXO1 gene fusions drive a subset of rhabdomyosarcoma (RMS) with poor survival; to date, these cancer drivers are therapeutically intractable. To identify new therapies for this disease, we undertook an isogenic CRISPR-interference screen to define PAX3-FOXO1-specific genetic dependencies and identified genes in the GATOR2 complex. GATOR2 loss in RMS abrogated aa-induced lysosomal localization of mTORC1 and consequent downstream signaling, slowing G1-S cell cycle transition. In vivo suppression of GATOR2 impaired the growth of tumor xenografts and favored the outgrowth of cells lacking PAX3-FOXO1. Loss of a subset of GATOR2 members can be compensated by direct genetic activation of mTORC1. RAS mutations are also sufficient to decouple mTORC1 activation from GATOR2, and indeed, fusion-negative RMS harboring such mutations exhibit aa-independent mTORC1 activity. A bisteric, mTORC1-selective small molecule induced tumor regressions in fusion-positive patient-derived tumor xenografts. These findings highlight a vulnerability in FOXO1 fusion-positive RMS and provide rationale for the clinical evaluation of bisteric mTORC1 inhibitors, currently in phase I testing, to treat this disease. Isogenic genetic screens can, thus, identify potentially exploitable vulnerabilities in fusion-driven pediatric cancers that otherwise remain mostly undruggable.
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Affiliation(s)
| | | | - José A. Garcia
- Division of Hematology-Oncology, Department of Medicine, UCSF, San Francisco, California, USA
- College of Osteopathic Medicine, Kansas City University, Kansas City, Missouri, USA
| | - Kristen Kwong
- Division of Pediatric Oncology, Department of Pediatrics, and
| | | | - Drew A. Fajardo
- Division of Hematology-Oncology, Department of Medicine, UCSF, San Francisco, California, USA
- School of Medicine, University of Nevada, Reno, Nevada, USA
| | - Yue Pan
- Division of Pediatric Oncology, Department of Pediatrics, and
| | - Max A. Horlbeck
- Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
- Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Jonathan S. Weissman
- Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
- Whitehead Institute, Boston, Massachusetts, USA
| | | | - Trever G. Bivona
- Division of Hematology-Oncology, Department of Medicine, UCSF, San Francisco, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Amit J. Sabnis
- Division of Pediatric Oncology, Department of Pediatrics, and
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21
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Intracellular galectin-3 is a lipopolysaccharide sensor that promotes glycolysis through mTORC1 activation. Nat Commun 2022; 13:7578. [PMID: 36481721 PMCID: PMC9732310 DOI: 10.1038/s41467-022-35334-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
How the carbohydrate binding protein galectin-3 might act as a diabetogenic and tumorogenic factor remains to be investigated. Here we report that intracellular galectin-3 interacts with Rag GTPases and Ragulator on lysosomes. We show that galectin-3 senses lipopolysaccharide (LPS) to facilitate the interaction of Rag GTPases and Ragulator, leading to the activation of mTORC1. We find that the lipopolysaccharide/galectin-3-Rag GTPases/Ragulator-mTORC1 axis regulates a cohort of genes including GLUT1, and HK2, and PKM2 that are critically involved in glucose uptake and glycolysis. Indeed, galectin-3 deficiency severely compromises LPS-promoted glycolysis. Importantly, the expression of HK2 is significantly reduced in diabetes patients. In multiple types of cancer including hepatocellular carcinoma (HCC), galectin-3 is highly expressed, and its level of expression is positively correlated with that of HK2 and PKM2 and negatively correlated with the prognosis of HCC patients. Our study unravels that galectin-3 is a sensor of LPS, an important modulator of the mTORC1 signaling, and a critical regulator of glucose metabolism.
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22
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Jansen RM, Peruzzo R, Fromm SA, Yokom AL, Zoncu R, Hurley JH. Structural basis for FLCN RagC GAP activation in MiT-TFE substrate-selective mTORC1 regulation. SCIENCE ADVANCES 2022; 8:eadd2926. [PMID: 36103527 PMCID: PMC9473554 DOI: 10.1126/sciadv.add2926] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/26/2022] [Indexed: 05/04/2023]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) regulates cell growth and catabolism in response to nutrients through phosphorylation of key substrates. The tumor suppressor folliculin (FLCN) is a RagC/D guanosine triphosphatase (GTPase)-activating protein (GAP) that regulates mTORC1 phosphorylation of MiT-TFE transcription factors, controlling lysosome biogenesis and autophagy. We determined the cryo-electron microscopy structure of the active FLCN complex (AFC) containing FLCN, FNIP2, the N-terminal tail of SLC38A9, the RagAGDP:RagCGDP.BeFx- GTPase dimer, and the Ragulator scaffold. Relative to the inactive lysosomal FLCN complex structure, FLCN reorients by 90°, breaks contact with RagA, and makes previously unseen contacts with RagC that position its Arg164 finger for catalysis. Disruption of the AFC-specific interfaces of FLCN and FNIP2 with RagC eliminated GAP activity and led to nuclear retention of TFE3, with no effect on mTORC1 substrates S6K or 4E-BP1. The structure provides a basis for regulation of an mTORC1 substrate-specific pathway and a roadmap to discover MiT-TFE family selective mTORC1 antagonists.
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Affiliation(s)
- Rachel M. Jansen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Roberta Peruzzo
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Simon A. Fromm
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Adam L. Yokom
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - James H. Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
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23
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Figlia G, Müller S, Hagenston AM, Kleber S, Roiuk M, Quast JP, Ten Bosch N, Carvajal Ibañez D, Mauceri D, Martin-Villalba A, Teleman AA. Brain-enriched RagB isoforms regulate the dynamics of mTORC1 activity through GATOR1 inhibition. Nat Cell Biol 2022; 24:1407-1421. [PMID: 36097071 PMCID: PMC9481464 DOI: 10.1038/s41556-022-00977-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 07/13/2022] [Indexed: 12/26/2022]
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) senses nutrient availability to appropriately regulate cellular anabolism and catabolism. During nutrient restriction, different organs in an animal do not respond equally, with vital organs being relatively spared. This raises the possibility that mTORC1 is differentially regulated in different cell types, yet little is known about this mechanistically. The Rag GTPases, RagA or RagB bound to RagC or RagD, tether mTORC1 in a nutrient-dependent manner to lysosomes where mTORC1 becomes activated. Although the RagA and B paralogues were assumed to be functionally equivalent, we find here that the RagB isoforms, which are highly expressed in neurons, impart mTORC1 with resistance to nutrient starvation by inhibiting the RagA/B GTPase-activating protein GATOR1. We further show that high expression of RagB isoforms is observed in some tumours, revealing an alternative strategy by which cancer cells can retain elevated mTORC1 upon low nutrient availability.
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Affiliation(s)
- Gianluca Figlia
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Sandra Müller
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Anna M Hagenston
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, INF 366, Heidelberg, Germany
| | - Susanne Kleber
- Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mykola Roiuk
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Jan-Philipp Quast
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Nora Ten Bosch
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Damian Carvajal Ibañez
- Heidelberg University, Heidelberg, Germany.,Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniela Mauceri
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, INF 366, Heidelberg, Germany
| | - Ana Martin-Villalba
- Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Aurelio A Teleman
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany. .,Heidelberg University, Heidelberg, Germany.
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24
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Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) senses nutrient levels in the cell and based on the availability, regulates cellular growth and proliferation. Its activity is tightly modulated by two GTPase units, the Rag GTPases and the Rheb GTPase. The Rag GTPases are the central hub of amino acid sensing as they summarize the amino acid signals from upstream regulators and control the subcellular localization of mTORC1. Unique from canonical signaling GTPases, the Rag GTPases are obligatory heterodimers, and the two subunits coordinate their nucleotide loading states to regulate their functional states. Robust biochemical analysis is indispensable to understanding the molecular mechanism governing the GTPase cycle. This chapter discusses protocols for purifying and biochemically characterizing the Rag GTPase heterodimer. We described two purification protocols to recombinantly produce the Rag GTPase heterodimer in large quantities. We then described assays to quantitatively measure the nucleotide binding and hydrolysis by the Rag GTPases. These assays allow for a thorough investigation of this unique heterodimeric GTPase, and they could be applicable to investigations of other noncanonical GTPases.
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Affiliation(s)
- Dylan D Doxsey
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States.
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25
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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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26
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Nowosad A, Besson A. Lysosomes at the Crossroads of Cell Metabolism, Cell Cycle, and Stemness. Int J Mol Sci 2022; 23:ijms23042290. [PMID: 35216401 PMCID: PMC8879101 DOI: 10.3390/ijms23042290] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 02/07/2023] Open
Abstract
Initially described as lytic bodies due to their degradative and recycling functions, lysosomes play a critical role in metabolic adaptation to nutrient availability. More recently, the contribution of lysosomal proteins to cell signaling has been established, and lysosomes have emerged as signaling hubs that regulate diverse cellular processes, including cell proliferation and cell fate. Deciphering these signaling pathways has revealed an extensive crosstalk between the lysosomal and cell cycle machineries that is only beginning to be understood. Recent studies also indicate that a number of lysosomal proteins are involved in the regulation of embryonic and adult stem cell fate and identity. In this review, we will focus on the role of the lysosome as a signaling platform with an emphasis on its function in integrating nutrient sensing with proliferation and cell cycle progression, as well as in stemness-related features, such as self-renewal and quiescence.
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Affiliation(s)
- Ada Nowosad
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France;
- Department of Oncology, KULeuven, Laboratory for Molecular Cancer Biology, Center for Cancer Biology, VIB, 3000 Leuven, Belgium
| | - Arnaud Besson
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France;
- Correspondence: ; Tel.: +33-561558486
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27
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Lei Y, Huang Y, Wen X, Yin Z, Zhang Z, Klionsky DJ. How Cells Deal with the Fluctuating Environment: Autophagy Regulation under Stress in Yeast and Mammalian Systems. Antioxidants (Basel) 2022; 11:antiox11020304. [PMID: 35204187 PMCID: PMC8868404 DOI: 10.3390/antiox11020304] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 01/28/2022] [Accepted: 01/31/2022] [Indexed: 12/04/2022] Open
Abstract
Eukaryotic cells frequently experience fluctuations of the external and internal environments, such as changes in nutrient, energy and oxygen sources, and protein folding status, which, after reaching a particular threshold, become a type of stress. Cells develop several ways to deal with these various types of stress to maintain homeostasis and survival. Among the cellular survival mechanisms, autophagy is one of the most critical ways to mediate metabolic adaptation and clearance of damaged organelles. Autophagy is maintained at a basal level under normal growing conditions and gets stimulated by stress through different but connected mechanisms. In this review, we summarize the advances in understanding the autophagy regulation mechanisms under multiple types of stress including nutrient, energy, oxidative, and ER stress in both yeast and mammalian systems.
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Affiliation(s)
- Yuchen Lei
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuxiang Huang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xin Wen
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhangyuan Yin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhihai Zhang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Daniel J. Klionsky
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Correspondence:
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28
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Doxsey DD, Veinotte K, Shen K. A New Crosslinking Assay to Study Guanine Nucleotide Binding in the Gtr Heterodimer of S. cerevisiae. Small GTPases 2022; 13:327-334. [PMID: 36328771 PMCID: PMC9639563 DOI: 10.1080/21541248.2022.2141019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) complex is responsible for coordinating nutrient availability with eukaryotic cell growth. Amino acid signals are transmitted towards mTOR via the Rag/Gtr heterodimers. Due to the obligatory heterodimeric architecture of the Rag/Gtr GTPases, investigating their biochemical properties has been challenging. Here, we describe an updated assay that allows us to probe the guanine nucleotide-binding affinity and kinetics to the Gtr heterodimers in Saccharomyces cerevisiae. We first identified the structural element that Gtr2p lacks to enable crosslinking. By using a sequence conservation-based mutation, we restored the crosslinking between Gtr2p and the bound nucleotides. Using this construct, we determined the nucleotide-binding affinities of the Gtr heterodimer, and found that it operates under a different form of intersubunit communication than human Rag GTPases. Our study defines the evolutionary divergence of the Gtr/Rag-mTOR axis of nutrient sensing.
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Affiliation(s)
- Dylan D. Doxsey
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA, 01605, USA
| | - Kristen Veinotte
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 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,Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation St, Worcester, MA, 01605, USA,CONTACT Kuang Shen Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA, 01605, USA
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29
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Shi Y, Xu S, Ngoi NYL, Hui Y, Ye Z. Rag GTPases suppress PRL-3 degradation and predict poor clinical diagnosis of cancer patients with low PRL-3 mRNA expression. Biochem Biophys Res Commun 2021; 576:108-116. [PMID: 34482023 DOI: 10.1016/j.bbrc.2021.08.090] [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: 08/13/2021] [Accepted: 08/28/2021] [Indexed: 11/18/2022]
Abstract
Ras-related GTP binding (Rag) GTPases are required to activate mechanistic target of rapamycin complex 1 (mTORC1), which plays a central role in cell growth and metabolism and is considered as one of the most important oncogenic pathways. Therefore, Rag GTPases have been speculated to play a pro-cancer role via mTOR induction. However, aside from stimulation of mTOR signaling, firm links connecting Rag GTPase activity and their downstream effectors with cancer progression, remain largely unreported. In this study, we reported a novel link between RagB/C and a known oncoprotein phosphatase of regenerating liver-3 (PRL-3) by screening 22 pairs of tumors and their adjacent normal tissues from gastric, liver and lung cancers, and validating our findings in cancer cell lines with ectopic RagB/C expression. RagB/C was found to enhance PRL-3 stability by modulating two major cellular protein degradation pathways: lysosomal-autophagy and ubiquitin-proteasome system (UPS). Functionally, we identified the correlation between RagB/C expression with poor clinical outcomes in breast or colon cancer patients who also showed low PRL-3 mRNA expression from data retrieved from TCGA datasets, highlighting the potential relevance of Rag GTPase and PRL-3 mRNA in combination as a prognostic clinical biomarker.
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Affiliation(s)
- Yin Shi
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| | - Shengfeng Xu
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, USA
| | - Natalie Y L Ngoi
- Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, USA; Department of Hematology-Oncology, National University Cancer Institute, Singapore, Singapore
| | - Yuanjian Hui
- Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Hubei, China
| | - Zu Ye
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Institute of Molecular and Cell Biology, A∗STAR (Agency for Science, Technology and Research), Singapore, Singapore; Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
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30
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Autophagy in Tumor Immunity and Viral-Based Immunotherapeutic Approaches in Cancer. Cells 2021; 10:cells10102672. [PMID: 34685652 PMCID: PMC8534833 DOI: 10.3390/cells10102672] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 09/22/2021] [Accepted: 09/27/2021] [Indexed: 01/09/2023] Open
Abstract
Autophagy is a fundamental catabolic process essential for the maintenance of cellular and tissue homeostasis, as well as directly contributing to the control of invading pathogens. Unsurprisingly, this process becomes critical in supporting cellular dysregulation that occurs in cancer, particularly the tumor microenvironments and their immune cell infiltration, ultimately playing a role in responses to cancer therapies. Therefore, understanding "cancer autophagy" could help turn this cellular waste-management service into a powerful ally for specific therapeutics. For instance, numerous regulatory mechanisms of the autophagic machinery can contribute to the anti-tumor properties of oncolytic viruses (OVs), which comprise a diverse class of replication-competent viruses with potential as cancer immunotherapeutics. In that context, autophagy can either: promote OV anti-tumor effects by enhancing infectivity and replication, mediating oncolysis, and inducing autophagic and immunogenic cell death; or reduce OV cytotoxicity by providing survival cues to tumor cells. These properties make the catabolic process of autophagy an attractive target for therapeutic combinations looking to enhance the efficacy of OVs. In this article, we review the complicated role of autophagy in cancer initiation and development, its effect on modulating OVs and immunity, and we discuss recent progress and opportunities/challenges in targeting autophagy to enhance oncolytic viral immunotherapy.
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31
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Fernandes SA, Demetriades C. The Multifaceted Role of Nutrient Sensing and mTORC1 Signaling in Physiology and Aging. FRONTIERS IN AGING 2021; 2:707372. [PMID: 35822019 PMCID: PMC9261424 DOI: 10.3389/fragi.2021.707372] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 08/12/2021] [Indexed: 01/10/2023]
Abstract
The mechanistic Target of Rapamycin (mTOR) is a growth-related kinase that, in the context of the mTOR complex 1 (mTORC1), touches upon most fundamental cellular processes. Consequently, its activity is a critical determinant for cellular and organismal physiology, while its dysregulation is commonly linked to human aging and age-related disease. Presumably the most important stimulus that regulates mTORC1 activity is nutrient sufficiency, whereby amino acids play a predominant role. In fact, mTORC1 functions as a molecular sensor for amino acids, linking the cellular demand to the nutritional supply. Notably, dietary restriction (DR), a nutritional regimen that has been shown to extend lifespan and improve healthspan in a broad spectrum of organisms, works via limiting nutrient uptake and changes in mTORC1 activity. Furthermore, pharmacological inhibition of mTORC1, using rapamycin or its analogs (rapalogs), can mimic the pro-longevity effects of DR. Conversely, nutritional amino acid overload has been tightly linked to aging and diseases, such as cancer, type 2 diabetes and obesity. Similar effects can also be recapitulated by mutations in upstream mTORC1 regulators, thus establishing a tight connection between mTORC1 signaling and aging. Although the role of growth factor signaling upstream of mTORC1 in aging has been investigated extensively, the involvement of signaling components participating in the nutrient sensing branch is less well understood. In this review, we provide a comprehensive overview of the molecular and cellular mechanisms that signal nutrient availability to mTORC1, and summarize the role that nutrients, nutrient sensors, and other components of the nutrient sensing machinery play in cellular and organismal aging.
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Affiliation(s)
- Stephanie A. Fernandes
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
- Cologne Graduate School for Ageing Research (CGA), Cologne, Germany
| | - Constantinos Demetriades
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
- Cologne Graduate School for Ageing Research (CGA), Cologne, Germany
- University of Cologne, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
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32
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Fingar DC. The yoga of Rag GTPases: Dynamic structural poses confer amino acid sensing by mTORC1. J Biol Chem 2021; 297:101103. [PMID: 34419448 PMCID: PMC8416955 DOI: 10.1016/j.jbc.2021.101103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heterodimeric Rag GTPases play a critical role in relaying fluctuating levels of cellular amino acids to the sensor mechanistic target of rapamycin complex 1. Important mechanistic questions remain unresolved, however, regarding how guanine nucleotide binding enables Rag GTPases to transition dynamically between distinct yoga-like structural poses that control activation state. Egri and Shen identified a critical interdomain hydrogen bond within RagA and RagC that stabilizes their GDP-bound states. They demonstrate that this long-distance interaction controls Rag structure and function to confer appropriate amino acid sensing by mechanistic target of rapamycin complex 1.
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Affiliation(s)
- Diane C Fingar
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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33
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Ortega-Molina A, Lebrero-Fernández C, Sanz A, Deleyto-Seldas N, Plata-Gómez AB, Menéndez C, Graña-Castro O, Caleiras E, Efeyan A. Inhibition of Rag GTPase signaling in mice suppresses B cell responses and lymphomagenesis with minimal detrimental trade-offs. Cell Rep 2021; 36:109372. [PMID: 34260908 PMCID: PMC8355512 DOI: 10.1016/j.celrep.2021.109372] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 05/12/2021] [Accepted: 06/18/2021] [Indexed: 12/19/2022] Open
Abstract
B lymphocytes are exquisitely sensitive to fluctuations in nutrient signaling by the Rag GTPases, and 15% of follicular lymphomas (FLs) harbor activating mutations in RRAGC. Hence, a potential therapeutic approach against malignant B cells is to inhibit Rag GTPase signaling, but because such inhibitors are still to be developed, efficacy and safety remain unknown. We generated knockin mice expressing a hypomorphic variant of RagC (Q119L); RagCQ119L/+ mice are viable and show attenuated nutrient signaling. B lymphocyte activation is cell-intrinsically impaired in RagCQ119L/+ mice, which also show significant suppression of genetically induced lymphomagenesis and autoimmunity. Surprisingly, no overt systemic trade-offs or phenotypic alterations caused by partial suppression of nutrient signaling are seen in other organs, and RagCQ119L/+ mice show normal longevity and normal age-dependent health decline. These results support the efficacy and safety of moderate inhibition of nutrient signaling against pathological B cells.
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Affiliation(s)
- Ana Ortega-Molina
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain.
| | - Cristina Lebrero-Fernández
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain
| | - Alba Sanz
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain
| | - Nerea Deleyto-Seldas
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain
| | - Ana Belén Plata-Gómez
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain
| | - Camino Menéndez
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain
| | - Osvaldo Graña-Castro
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Eduardo Caleiras
- Histopathology Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Alejo Efeyan
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain.
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34
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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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An interdomain hydrogen bond in the Rag GTPases maintains stable mTORC1 signaling in sensing amino acids. J Biol Chem 2021; 297:100861. [PMID: 34116056 PMCID: PMC8254048 DOI: 10.1016/j.jbc.2021.100861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/27/2021] [Accepted: 06/07/2021] [Indexed: 01/09/2023] Open
Abstract
Cellular growth and proliferation are primarily dictated by the mechanistic target of rapamycin complex 1 (mTORC1), which balances nutrient availability against the cell’s anabolic needs. Central to the activity of mTORC1 is the RagA–RagC GTPase heterodimer, which under favorable conditions recruits the complex to the lysosomal surface to promote its activity. The RagA–RagC heterodimer has a unique architecture in that both subunits are active GTPases. To promote mTORC1 activity, the RagA subunit is loaded with GTP and the RagC subunit is loaded with GDP, while the opposite nucleotide-loading configuration inhibits this signaling pathway. Despite its unique molecular architecture, how the Rag GTPase heterodimer maintains the oppositely loaded nucleotide state remains elusive. Here, we applied structure–function analysis approach to the crystal structures of the Rag GTPase heterodimer and identified a key hydrogen bond that stabilizes the GDP-loaded state of the Rag GTPases. This hydrogen bond is mediated by the backbone carbonyl of Asn30 in the nucleotide-binding domain of RagA or Lys84 of RagC and the hydroxyl group on the side chain of Thr210 in the C-terminal roadblock domain of RagA or Ser266 of RagC, respectively. Eliminating this interdomain hydrogen bond abolishes the ability of the Rag GTPase to maintain its functional state, resulting in a distorted response to amino acid signals. Our results reveal that this long-distance interdomain interaction within the Rag GTPase is required for the maintenance and regulation of the mTORC1 nutrient-sensing pathway.
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Zhong J, Han C, Zhang X, Chen P, Liu R. scGET: Predicting Cell Fate Transition During Early Embryonic Development by Single-cell Graph Entropy. GENOMICS, PROTEOMICS & BIOINFORMATICS 2021; 19:461-474. [PMID: 34954425 PMCID: PMC8864248 DOI: 10.1016/j.gpb.2020.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 11/08/2020] [Accepted: 01/02/2021] [Indexed: 01/26/2023]
Abstract
During early embryonic development, cell fate commitment represents a critical transition or "tipping point" of embryonic differentiation, at which there is a drastic and qualitative shift of the cell populations. In this study, we presented a computational approach, scGET, to explore the gene-gene associations based on single-cell RNA sequencing (scRNA-seq) data for critical transition prediction. Specifically, by transforming the gene expression data to the local network entropy, the single-cell graph entropy (SGE) value quantitatively characterizes the stability and criticality of gene regulatory networks among cell populations and thus can be employed to detect the critical signal of cell fate or lineage commitment at the single-cell level. Being applied to five scRNA-seq datasets of embryonic differentiation, scGET accurately predicts all the impending cell fate transitions. After identifying the "dark genes" that are non-differentially expressed genes but sensitive to the SGE value, the underlying signaling mechanisms were revealed, suggesting that the synergy of dark genes and their downstream targets may play a key role in various cell development processes.The application in all five datasets demonstrates the effectiveness of scGET in analyzing scRNA-seq data from a network perspective and its potential to track the dynamics of cell differentiation. The source code of scGET is accessible at https://github.com/zhongjiayuna/scGET_Project.
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Affiliation(s)
- Jiayuan Zhong
- School of Mathematics, South China University of Technology, Guangzhou 510640, PR China
| | - Chongyin Han
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Xuhang Zhang
- School of Computer Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Pei Chen
- School of Mathematics, South China University of Technology, Guangzhou 510640, PR China.
| | - Rui Liu
- School of Mathematics, South China University of Technology, Guangzhou 510640, PR China; Pazhou Lab, Guangzhou 510330, PR China.
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37
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Kim M, Lu L, Dvornikov AV, Ma X, Ding Y, Zhu P, Olson TM, Lin X, Xu X. TFEB Overexpression, Not mTOR Inhibition, Ameliorates RagC S75Y Cardiomyopathy. Int J Mol Sci 2021; 22:5494. [PMID: 34071043 PMCID: PMC8197163 DOI: 10.3390/ijms22115494] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 12/29/2022] Open
Abstract
A de novo missense variant in Rag GTPase protein C (RagCS75Y) was recently identified in a syndromic dilated cardiomyopathy (DCM) patient. However, its pathogenicity and the related therapeutic strategy remain unclear. We generated a zebrafish RragcS56Y (corresponding to human RagCS75Y) knock-in (KI) line via TALEN technology. The KI fish manifested cardiomyopathy-like phenotypes and poor survival. Overexpression of RagCS75Y via adenovirus infection also led to increased cell size and fetal gene reprogramming in neonatal rat ventricle cardiomyocytes (NRVCMs), indicating a conserved mechanism. Further characterization identified aberrant mammalian target of rapamycin complex 1 (mTORC1) and transcription factor EB (TFEB) signaling, as well as metabolic abnormalities including dysregulated autophagy. However, mTOR inhibition failed to ameliorate cardiac phenotypes in the RagCS75Y cardiomyopathy models, concomitant with a failure to promote TFEB nuclear translocation. This observation was at least partially explained by increased and mTOR-independent physical interaction between RagCS75Y and TFEB in the cytosol. Importantly, TFEB overexpression resulted in more nuclear TFEB and rescued cardiomyopathy phenotypes. These findings suggest that S75Y is a pathogenic gain-of-function mutation in RagC that leads to cardiomyopathy. A primary pathological step of RagCS75Y cardiomyopathy is defective mTOR-TFEB signaling, which can be corrected by TFEB overexpression, but not mTOR inhibition.
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Affiliation(s)
- Maengjo Kim
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Linghui Lu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Alexey V. Dvornikov
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, AZ 85721, USA
| | - Xiao Ma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Yonghe Ding
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Ping Zhu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Timothy M. Olson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
- Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN 55901, USA
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA; (M.K.); (L.L.); (A.V.D.); (X.M.); (Y.D.); (P.Z.); (X.L.)
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55901, USA;
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Hirst J, Hesketh GG, Gingras AC, Robinson MS. Rag GTPases and phosphatidylinositol 3-phosphate mediate recruitment of the AP-5/SPG11/SPG15 complex. J Cell Biol 2021; 220:211690. [PMID: 33464297 PMCID: PMC7814351 DOI: 10.1083/jcb.202002075] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/21/2020] [Accepted: 12/02/2020] [Indexed: 12/31/2022] Open
Abstract
Adaptor protein complex 5 (AP-5) and its partners, SPG11 and SPG15, are recruited onto late endosomes and lysosomes. Here we show that recruitment of AP-5/SPG11/SPG15 is enhanced in starved cells and occurs by coincidence detection, requiring both phosphatidylinositol 3-phosphate (PI3P) and Rag GTPases. PI3P binding is via the SPG15 FYVE domain, which, on its own, localizes to early endosomes. GDP-locked RagC promotes recruitment of AP-5/SPG11/SPG15, while GTP-locked RagA prevents its recruitment. Our results uncover an interplay between AP-5/SPG11/SPG15 and the mTORC1 pathway and help to explain the phenotype of AP-5/SPG11/SPG15 deficiency in patients, including the defect in autophagic lysosome reformation.
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Affiliation(s)
- Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK,Jennifer Hirst:
| | - Geoffrey G. Hesketh
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Margaret S. Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK,Correspondence to Margaret S. Robinson:
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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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40
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Morozumi Y, Shiozaki K. Conserved and Divergent Mechanisms That Control TORC1 in Yeasts and Mammals. Genes (Basel) 2021; 12:genes12010088. [PMID: 33445779 PMCID: PMC7828246 DOI: 10.3390/genes12010088] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 12/23/2022] Open
Abstract
Target of rapamycin complex 1 (TORC1), a serine/threonine-protein kinase complex highly conserved among eukaryotes, coordinates cellular growth and metabolism with environmental cues, including nutrients and growth factors. Aberrant TORC1 signaling is associated with cancers and various human diseases, and TORC1 also plays a key role in ageing and lifespan, urging current active research on the mechanisms of TORC1 regulation in a variety of model organisms. Identification and characterization of the RAG small GTPases as well as their regulators, many of which are highly conserved from yeast to humans, led to a series of breakthroughs in understanding the molecular bases of TORC1 regulation. Recruitment of mammalian TORC1 (mTORC1) by RAGs to lysosomal membranes is a key step for mTORC1 activation. Interestingly, the RAG GTPases in fission yeast are primarily responsible for attenuation of TORC1 activity on vacuoles, the yeast equivalent of lysosomes. In this review, we summarize our current knowledge about the functions of TORC1 regulators on yeast vacuoles, and illustrate the conserved and divergent mechanisms of TORC1 regulation between yeasts and mammals.
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Affiliation(s)
- Yuichi Morozumi
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan;
- Correspondence: ; Tel.: +81-743-72-5543
| | - Kazuhiro Shiozaki
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan;
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
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41
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Smailov B, Alybayev S, Smekenov I, Mursalimov A, Saparbaev M, Sarbassov D, Bissenbaev A. Wheat Germination Is Dependent on Plant Target of Rapamycin Signaling. Front Cell Dev Biol 2020; 8:606685. [PMID: 33330509 PMCID: PMC7719826 DOI: 10.3389/fcell.2020.606685] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 10/21/2020] [Indexed: 12/21/2022] Open
Abstract
Germination is a process of seed sprouting that facilitates embryo growth. The breakdown of reserved starch in the endosperm into simple sugars is essential for seed germination and subsequent seedling growth. At the early stage of germination, gibberellic acid (GA) activates transcription factor GAMYB to promote de novo synthesis of isoforms of α-amylase in the aleurone layer and scutellar epithelium of the embryo. Here, we demonstrate that wheat germination is regulated by plant target of rapamycin (TOR) signaling. TOR is a central component of the essential-nutrient–dependent pathway controlling cell growth in all eukaryotes. It is known that rapamycin, a highly specific allosteric inhibitor of TOR, is effective in yeast and animal cells but ineffective in most of higher plants likely owing to structural differences in ubiquitous rapamycin receptor FKBP12. The action of rapamycin on wheat growth has not been studied. Our data show that rapamycin inhibits germination of wheat seeds and of their isolated embryos in a dose-dependent manner. The involvement of Triticum aestivum TOR (TaTOR) in wheat germination was consistent with the suppression of wheat embryo growth by specific inhibitors of the TOR kinase: pp242 or torin1. Rapamycin or torin1 interfered with GA function in germination because of a potent inhibitory effect on α-amylase and GAMYB gene expression. The TOR inhibitors selectively targeted the GA-dependent gene expression, whereas expression of the abscisic acid-dependent ABI5 gene was not affected by either rapamycin or torin1. To determine whether the TaTOR kinase activation takes place during wheat germination, we examined phosphorylation of a ribosomal protein, T. aestivum S6 kinase 1 (TaS6K1; a substrate of TOR). The phosphorylation of serine 467 (S467) in a hydrophobic motif on TaS6K1 was induced in a process of germination triggered by GA. Moreover, the germination-induced phosphorylation of TaS6K1 on S467 was dependent on TaTOR and was inhibited by rapamycin or torin1. Besides, a gibberellin biosynthesis inhibitor (paclobutrazol; PBZ) blocked not only α-amylase gene expression but also TaS6K1 phosphorylation in wheat embryos. Thus, a hormonal action of GA turns on the synthesis of α-amylase in wheat germination via activation of the TaTOR–S6K1 signaling pathway.
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Affiliation(s)
- Bauyrzhan Smailov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Sanzhar Alybayev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Izat Smekenov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Aibek Mursalimov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Murat Saparbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Groupe «Mechanisms of DNA Repair and Carcinogenesis», Equipe Labellisée LIGUE 2016, CNRS UMR 9019, Université Paris-Sud, Gustave Roussy Cancer Campus, Villejuif, France
| | - Dos Sarbassov
- Department of Biology, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Amangeldy Bissenbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
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42
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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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Tafur L, Kefauver J, Loewith R. Structural Insights into TOR Signaling. Genes (Basel) 2020; 11:E885. [PMID: 32759652 PMCID: PMC7464330 DOI: 10.3390/genes11080885] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 12/31/2022] Open
Abstract
The Target of Rapamycin (TOR) is a highly conserved serine/threonine protein kinase that performs essential roles in the control of cellular growth and metabolism. TOR acts in two distinct multiprotein complexes, TORC1 and TORC2 (mTORC1 and mTORC2 in humans), which maintain different aspects of cellular homeostasis and orchestrate the cellular responses to diverse environmental challenges. Interest in understanding TOR signaling is further motivated by observations that link aberrant TOR signaling to a variety of diseases, ranging from epilepsy to cancer. In the last few years, driven in large part by recent advances in cryo-electron microscopy, there has been an explosion of available structures of (m)TORC1 and its regulators, as well as several (m)TORC2 structures, derived from both yeast and mammals. In this review, we highlight and summarize the main findings from these reports and discuss both the fascinating and unexpected molecular biology revealed and how this knowledge will potentially contribute to new therapeutic strategies to manipulate signaling through these clinically relevant pathways.
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Affiliation(s)
- Lucas Tafur
- Department of Molecular Biology, University of Geneva, 30 quai Ernest-Ansermet, CH1211 Geneva, Switzerland; (L.T.); (J.K.)
| | - Jennifer Kefauver
- Department of Molecular Biology, University of Geneva, 30 quai Ernest-Ansermet, CH1211 Geneva, Switzerland; (L.T.); (J.K.)
| | - Robbie Loewith
- Department of Molecular Biology, University of Geneva, 30 quai Ernest-Ansermet, CH1211 Geneva, Switzerland; (L.T.); (J.K.)
- Swiss National Centre for Competence in Research (NCCR) in Chemical Biology, University of Geneva, Sciences II, Room 3-308, 30 Quai Ernest-Ansermet, CH1211 Geneva, Switzerland
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Kanade M, Chakraborty S, Shelke SS, Gayathri P. A Distinct Motif in a Prokaryotic Small Ras-Like GTPase Highlights Unifying Features of Walker B Motifs in P-Loop NTPases. J Mol Biol 2020; 432:5544-5564. [PMID: 32750390 DOI: 10.1016/j.jmb.2020.07.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/22/2020] [Accepted: 07/30/2020] [Indexed: 01/22/2023]
Abstract
A hallmark of the catalytically essential Walker B motif of P-loop NTPases is the presence of an acidic residue (aspartate/glutamate) for efficient Mg2+ coordination. Although the Walker B motif has been identified in well-studied examples of P-loop NTPases, its identity is ambiguous in many families, for example, in the prokaryotic small Ras-like GTPase family of MglA. MglA, belonging to TRAFAC class of P-loop NTPases, possesses a threonine at the position equivalent to Walker B aspartate in eukaryotic Ras-like GTPases. To resolve the identity of the Walker B residue in MglA, we carried out a comprehensive analysis of Mg2+ coordination on P-loop NTPase structures. Atoms in the octahedral coordination of Mg2+ and their interactions comprise a network including water molecules, Walker A, Walker B and switch motifs of P-loop NTPases. Based on the conserved geometry of Mg2+ coordination, we confirm that a conserved aspartate functions as the Walker B residue of MglA, and validate it through mutagenesis and biochemical characterization. Location of the newly identified aspartate is spatially equivalent to the Walker B residue of the ASCE division of P-loop NTPases. Furthermore, similar to the allosteric regulation of the Walker B aspartate conformation in MglA, we identify protein families in which large conformational changes involving Walker B motif potentially function as allosteric regulators. The study unravels conserved features of Mg2+ coordination among divergent families of P-loop NTPases, especially between ancient Ras-like GTPases and ASCE family of ATPases. The conserved geometric features provide a foundation for design of nucleotide-hydrolyzing enzymes.
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Affiliation(s)
- Manil Kanade
- Indian Institute of Science Education and Research, Pune, India
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45
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de Martín Garrido N, Aylett CHS. Nutrient Signaling and Lysosome Positioning Crosstalk Through a Multifunctional Protein, Folliculin. Front Cell Dev Biol 2020; 8:108. [PMID: 32195250 PMCID: PMC7063858 DOI: 10.3389/fcell.2020.00108] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 02/10/2020] [Indexed: 12/16/2022] Open
Abstract
FLCN was identified as the gene responsible for Birt-Hogg-Dubé (BHD) syndrome, a hereditary syndrome associated with the appearance of familiar renal oncocytomas. Most mutations affecting FLCN result in the truncation of the protein, and therefore loss of its associated functions, as typical for a tumor suppressor. FLCN encodes the protein folliculin (FLCN), which is involved in numerous biological processes; mutations affecting this protein thus lead to different phenotypes depending on the cellular context. FLCN forms complexes with two large interacting proteins, FNIP1 and FNIP2. Structural studies have shown that both FLCN and FNIPs contain longin and differentially expressed in normal versus neoplastic cells (DENN) domains, typically involved in the regulation of small GTPases. Accordingly, functional studies show that FLCN regulates both the Rag and the Rab GTPases depending on nutrient availability, which are respectively involved in the mTORC1 pathway and lysosomal positioning. Although recent structural studies shed light on the precise mechanism by which FLCN regulates the Rag GTPases, which in turn regulate mTORC1, how FLCN regulates membrane trafficking through the Rab GTPases or the significance of the intriguing FLCN-FNIP-AMPK complex formation are questions that still remain unanswered. We discuss the recent progress in our understanding of FLCN regulation of both growth signaling and lysosomal positioning, as well as future approaches to establish detailed mechanisms to explain the disparate phenotypes caused by the loss of FLCN function and the development of BHD-associated and other tumors.
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Affiliation(s)
| | - Christopher H. S. Aylett
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
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46
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Park JH, Lee G, Blenis J. Structural Insights into the Activation of mTORC1 on the Lysosomal Surface. Trends Biochem Sci 2020; 45:367-369. [PMID: 32311329 DOI: 10.1016/j.tibs.2020.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 12/25/2022]
Abstract
Using cryo-electron microscopy and molecular characterization, David Sabatini and colleagues provide crucial new insights that validate and expand their model of how amino acids are sensed and signal at the lysosome to activate mechanistic target of rapamycin complex 1 (mTORC1) and cell growth-regulating processes. This work also reveals new therapeutic opportunities for mTORC1-driven diseases.
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Affiliation(s)
- Jin H Park
- Meyer Cancer Center and Department of Pharmacology, Weill Cornell Medicine, New York, NY 10021, USA.
| | - Gina Lee
- Meyer Cancer Center and Department of Pharmacology, Weill Cornell Medicine, New York, NY 10021, USA
| | - John Blenis
- Meyer Cancer Center and Department of Pharmacology, Weill Cornell Medicine, New York, NY 10021, USA.
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47
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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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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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49
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Lawrence RE, Fromm SA, Fu Y, Yokom AL, Kim DJ, Thelen AM, Young LN, Lim CY, Samelson AJ, Hurley JH, Zoncu R. Structural mechanism of a Rag GTPase activation checkpoint by the lysosomal folliculin complex. Science 2019; 366:971-977. [PMID: 31672913 DOI: 10.1126/science.aax0364] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 10/23/2019] [Indexed: 12/16/2022]
Abstract
The tumor suppressor folliculin (FLCN) enables nutrient-dependent activation of the mechanistic target of rapamycin complex 1 (mTORC1) protein kinase via its guanosine triphosphatase (GTPase) activating protein (GAP) activity toward the GTPase RagC. Concomitant with mTORC1 inactivation by starvation, FLCN relocalizes from the cytosol to lysosomes. To determine the lysosomal function of FLCN, we reconstituted the human lysosomal FLCN complex (LFC) containing FLCN, its partner FLCN-interacting protein 2 (FNIP2), and the RagAGDP:RagCGTP GTPases as they exist in the starved state with their lysosomal anchor Ragulator complex and determined its cryo-electron microscopy structure to 3.6 angstroms. The RagC-GAP activity of FLCN was inhibited within the LFC, owing to displacement of a catalytically required arginine in FLCN from the RagC nucleotide. Disassembly of the LFC and release of the RagC-GAP activity of FLCN enabled mTORC1-dependent regulation of the master regulator of lysosomal biogenesis, transcription factor E3, implicating the LFC as a checkpoint in mTORC1 signaling.
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Affiliation(s)
- Rosalie E Lawrence
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Simon A Fromm
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Yangxue Fu
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Adam L Yokom
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Do Jin Kim
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Ashley M Thelen
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Lindsey N Young
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Chun-Yan Lim
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA.,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Avi J Samelson
- The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA.,Institute for Neurodegenerative Diseases, University of California at San Francisco, San Francisco, CA 94158, USA
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA. .,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA. .,The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
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50
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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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