1
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Wu C, Zhong R, Wei T, Jin Y, He C, Li H, Cheng Y. Mechanism of targeting the mTOR pathway to regulate ferroptosis in NSCLC with different EGFR mutations. Oncol Lett 2024; 28:298. [PMID: 38751752 PMCID: PMC11094585 DOI: 10.3892/ol.2024.14431] [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: 11/21/2023] [Accepted: 03/15/2024] [Indexed: 05/18/2024] Open
Abstract
Patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR)-activating mutations can be treated with EGFR-tyrosine kinase inhibitors (TKIs). Although EGFR-TKI-targeted drugs bring survival promotion in patients with EGFR mutations, drug resistance is inevitable, so it is urgent to explore new treatments to overcome drug resistance. In addition, wild-type EGFR lacks targeted drugs, and new targeted therapies need to be explored. Ferroptosis is a key research direction for overcoming drug resistance. However, the role and mechanism of regulating ferroptosis in different EGFR-mutant NSCLC types remains unclear. In the present study, H1975 (EGFR T790M/L858R mutant), A549 (EGFR wild-type) and H3255 (EGFR L858R mutant) NSCLC cell lines were used. The expression of ferroptosis markers in these cell lines was detected using western blotting and reverse transcription-quantitative PCR. Cell viability was determined using the MTT assay and reactive oxygen species (ROS) levels were measured using flow cytometry. The results showed that, compared with EGFR wild-type/sensitive mutant cells, EGFR-resistant mutant cells were more sensitive to the ferroptosis inducer, erastin. Furthermore, the mammalian target of rapamycin (mTOR) inhibitor, everolimus (RAD001), induced cell death in all three cell lines in a dose-dependent manner. The ferroptosis inhibitor, ferrostatin-1, could reverse cell death in EGFR-resistant mutant and EGFR wild-type cells induced by RAD001, but could not reverse cell death in EGFR-sensitive mutant cells. Compared with EGFR wild-type/sensitive mutant cells, EGFR-resistant mutant cells were more sensitive to RAD001 combined with erastin. In addition, a high-dose of RAD001 reduced the expression levels of ferritin heavy-chain polypeptide 1 (FTH1), glutathione peroxidase 4 (GPX4) and ferroportin and significantly increased ROS and malondialdehyde (MDA) levels in EGFR-resistant mutant and EGFR wild-type cells. In the present study, GPX4 inhibitor only or combined with RAD001 inhibited the AKT/mTOR pathway in EGFR-resistant mutant cells. Therefore, the results of the present study suggested that inhibition of the mTOR pathway may downregulate the expression of ferroptosis-related proteins in EGFR-resistant and EGFR wild-type NSCLC cells, increase the ROS and MDA levels and ultimately induce ferroptosis.
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Affiliation(s)
- Chunjiao Wu
- Phase I Clinical Research Ward, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
| | - Rui Zhong
- Translational Cancer Research Lab, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
- Jilin Provincial Key Laboratory of Molecular Diagnostics for Lung Cancer, Changchun, Jilin 130000, P.R. China
| | - Tianxue Wei
- Biobank, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
| | - Yulong Jin
- Biobank, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
| | - Chunying He
- Biobank, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
| | - Hui Li
- Translational Cancer Research Lab, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
- Jilin Provincial Key Laboratory of Molecular Diagnostics for Lung Cancer, Changchun, Jilin 130000, P.R. China
- Biobank, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
| | - Ying Cheng
- Translational Cancer Research Lab, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
- Jilin Provincial Key Laboratory of Molecular Diagnostics for Lung Cancer, Changchun, Jilin 130000, P.R. China
- Department of Medical Thoracic Oncology, Jilin Cancer Hospital, Changchun, Jilin 130000, P.R. China
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2
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Wang Y, Vandewalle N, De Veirman K, Vanderkerken K, Menu E, De Bruyne E. Targeting mTOR signaling pathways in multiple myeloma: biology and implication for therapy. Cell Commun Signal 2024; 22:320. [PMID: 38862983 PMCID: PMC11165851 DOI: 10.1186/s12964-024-01699-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 06/03/2024] [Indexed: 06/13/2024] Open
Abstract
Multiple Myeloma (MM), a cancer of terminally differentiated plasma cells, is the second most prevalent hematological malignancy and is incurable due to the inevitable development of drug resistance. Intense protein synthesis is a distinctive trait of MM cells, supporting the massive production of clonal immunoglobulins or free light chains. The mammalian target of rapamycin (mTOR) kinase is appreciated as a master regulator of vital cellular processes, including regulation of metabolism and protein synthesis, and can be found in two multiprotein complexes, mTORC1 and mTORC2. Dysregulation of these complexes is implicated in several types of cancer, including MM. Since mTOR has been shown to be aberrantly activated in a large portion of MM patients and to play a role in stimulating MM cell survival and resistance to several existing therapies, understanding the regulation and functions of the mTOR complexes is vital for the development of more effective therapeutic strategies. This review provides a general overview of the mTOR pathway, discussing key discoveries and recent insights related to the structure and regulation of mTOR complexes. Additionally, we highlight findings on the mechanisms by which mTOR is involved in protein synthesis and delve into mTOR-mediated processes occurring in MM. Finally, we summarize the progress and current challenges of drugs targeting mTOR complexes in MM.
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Affiliation(s)
- Yanmeng Wang
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Niels Vandewalle
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Kim De Veirman
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Universitair Ziekenhuis Brussel (UZ Brussel), Jette, Belgium
| | - Karin Vanderkerken
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Eline Menu
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium.
| | - Elke De Bruyne
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium.
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3
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Artins A, Martins MCM, Meyer C, Fernie AR, Caldana C. Sensing and regulation of C and N metabolism - novel features and mechanisms of the TOR and SnRK1 signaling pathways. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1268-1280. [PMID: 38349940 DOI: 10.1111/tpj.16684] [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: 12/16/2022] [Revised: 01/25/2024] [Accepted: 02/02/2024] [Indexed: 02/15/2024]
Abstract
Carbon (C) and nitrogen (N) metabolisms are tightly integrated to allow proper plant growth and development. Photosynthesis is dependent on N invested in chlorophylls, enzymes, and structural components of the photosynthetic machinery, while N uptake and assimilation rely on ATP, reducing equivalents, and C-skeletons provided by photosynthesis. The direct connection between N availability and photosynthetic efficiency allows the synthesis of precursors for all metabolites and building blocks in plants. Thus, the capacity to sense and respond to sudden changes in C and N availability is crucial for plant survival and is mediated by complex yet efficient signaling pathways such as TARGET OF RAPAMYCIN (TOR) and SUCROSE-NON-FERMENTING-1-RELATED PROTEIN KINASE 1 (SnRK1). In this review, we present recent advances in mechanisms involved in sensing C and N status as well as identifying current gaps in our understanding. We finally attempt to provide new perspectives and hypotheses on the interconnection of diverse signaling pathways that will allow us to understand the integration and orchestration of the major players governing the regulation of the CN balance.
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Affiliation(s)
- Anthony Artins
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
| | - Marina C M Martins
- in Press - Scientific Consulting and Communication Services, 05089-030, São Paulo, São Paulo, Brazil
| | - Christian Meyer
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
| | - Camila Caldana
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
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4
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Jin E, Wang S, Chen D, Wang JP, Zeng Y, Sun R, Zhang HT. P4HA2 activates mTOR via hydroxylation and targeting P4HA2-mTOR inhibits lung adenocarcinoma cell growth. Oncogene 2024; 43:1813-1823. [PMID: 38654109 PMCID: PMC11164680 DOI: 10.1038/s41388-024-03032-1] [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: 11/01/2023] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/25/2024]
Abstract
Mammalian target of rapamycin (mTOR) kinase functions as a central regulator of cell growth and metabolism, and its complexes mTORC1 and mTORC2 phosphorylate distinct substrates. Dysregulation of mTOR signaling is commonly implicated in human diseases, including cancer. Despite three decades of active research in mTOR, much remains to be determined. Here, we demonstrate that prolyl 4-hydroxylase alpha-2 (P4HA2) binds directly to mTOR and hydroxylates one highly conserved proline 2341 (P2341) within a kinase domain of mTOR, thereby activating mTOR kinase and downstream effector proteins (e.g. S6K and AKT). Moreover, the hydroxylation of P2341 strengthens mTOR stability and allows mTOR to accurately recognize its substrates such as S6K and AKT. The growth of lung adenocarcinoma cells overexpressing mTORP2341A is significantly reduced when compared with that of cells overexpressing mTORWT. Interestingly, in vivo cell growth assays show that targeting P4HA2-mTOR significantly suppresses lung adenocarcinoma cell growth. In summary, our study reveals an undiscovered hydroxylation-regulatory mechanism by which P4HA2 directly activates mTOR kinase, providing insights for therapeutically targeting mTOR kinase-driven cancers.
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Affiliation(s)
- Ersuo Jin
- Soochow University Laboratory of Cancer Molecular Genetics, Collaborative Innovation Center of Molecular Medicine between Soochow University and Donghai County People's Hospital, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
- Department of Genetics, School of Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
| | - Shengjie Wang
- Soochow University Laboratory of Cancer Molecular Genetics, Collaborative Innovation Center of Molecular Medicine between Soochow University and Donghai County People's Hospital, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
- Department of Basic Medicine, Kangda College of Nanjing Medical University, Lianyungang, 222000, Jiangsu Province, China
| | - Donglai Chen
- Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Jia-Ping Wang
- Soochow University Laboratory of Cancer Molecular Genetics, Collaborative Innovation Center of Molecular Medicine between Soochow University and Donghai County People's Hospital, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China
- Donghai County People's Hospital, Lianyungang, 222000, Jiangsu Province, China
| | - Yuanyuan Zeng
- Department of Respiratory Medicine, The First Affiliated Hospital of Soochow University, Suzhou Medical College of Soochow University, Suzhou, 215006, Jiangsu Province, China
| | - Runfeng Sun
- Soochow University Laboratory of Cancer Molecular Genetics, Collaborative Innovation Center of Molecular Medicine between Soochow University and Donghai County People's Hospital, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China.
- Donghai County People's Hospital, Lianyungang, 222000, Jiangsu Province, China.
| | - Hong-Tao Zhang
- Soochow University Laboratory of Cancer Molecular Genetics, Collaborative Innovation Center of Molecular Medicine between Soochow University and Donghai County People's Hospital, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China.
- Department of Genetics, School of Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, 215123, Jiangsu Province, China.
- Suzhou Key Laboratory for Molecular Cancer Genetics, Suzhou, 215123, Jiangsu Province, China.
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5
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Rameh LE, York JD, Blind RD. Multiple inositol phosphate species enhance stability of active mTOR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.592113. [PMID: 38746235 PMCID: PMC11092565 DOI: 10.1101/2024.05.01.592113] [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
Mechanistic Target of Rapamycin (mTOR) binds the small metabolite inositol hexakisphosphate (IP6) as shown in structures of mTOR, however it remains unclear if IP6, or any other inositol phosphate species, can activate mTOR kinase activity. Here, we show that multiple, exogenously added inositol phosphate species (IP6, IP5, IP4 and IP3) can all enhance the ability of mTOR and mTORC1 to auto-phosphorylate and incorporate radiolabeled phosphate into peptide substrates in in vitro kinase reactions. Although IP6 did not affect the apparent KM of mTORC1 for ATP, monitoring kinase activity over longer reaction times showed increased product formation, suggesting inositol phosphates stabilize an active form of mTORC1 in vitro. The effects of IP6 on mTOR were reversible, suggesting IP6 bound to mTOR can be exchanged dynamically with the free solvent. Interestingly, we also observed that IP6 could alter mTOR solubility and electrophoretic mobility in SDS-PAGE in the presence of manganese, suggesting divalent cations may play a role in inositol phosphate regulation of mTOR. Together, these data suggest for the first time that multiple inositol phosphate species (IP4, IP5 and IP6) can dynamically regulate mTOR and mTORC1 by promoting a stable, active state of the kinase. Our data suggest that studies of the dynamics of inositol phosphate regulation of mTOR are well justified.
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Affiliation(s)
- Lucia E. Rameh
- University of South Alabama, Department of Biochemistry and Molecular Biology, Mobile, AL 36688
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
- Vanderbilt University Medical Center, Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Nashville, TN 37232
| | - John D. York
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
| | - Raymond D. Blind
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
- Vanderbilt University Medical Center, Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Nashville, TN 37232
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6
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Wang T, He M, Zhang X, Guo Z, Wang P, Long F. Deciphering the impact of circRNA-mediated autophagy on tumor therapeutic resistance: a novel perspective. Cell Mol Biol Lett 2024; 29:60. [PMID: 38671354 PMCID: PMC11046940 DOI: 10.1186/s11658-024-00571-z] [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: 01/03/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
Cancer therapeutic resistance remains a significant challenge in the pursuit of effective treatment strategies. Circular RNAs (circRNAs), a class of non-coding RNAs, have recently emerged as key regulators of various biological processes, including cancer progression and drug resistance. This review highlights the emerging role of circRNAs-mediated autophagy in cancer therapeutic resistance, a cellular process that plays a dual role in cancer by promoting both cell survival and death. Increasing evidence suggests that circRNAs can modulate autophagy pathways, thereby influencing the response of cancer cells to therapeutic agents. In this context, the intricate interplay between circRNAs, autophagy, and therapeutic resistance is explored. Various mechanisms are discussed through which circRNAs can impact autophagy, including direct interactions with autophagy-related genes, modulation of signaling pathways, and cross-talk with other non-coding RNAs. Furthermore, the review delves into specific examples of how circRNA-mediated autophagy regulation can contribute to resistance against chemotherapy and radiotherapy. Understanding these intricate molecular interactions provides valuable insights into potential strategies for overcoming therapeutic resistance in cancer. Exploiting circRNAs as therapeutic targets or utilizing them as diagnostic and predictive biomarkers opens new avenues for developing personalized treatment approaches. In summary, this review underscores the importance of circRNA-mediated autophagy in cancer therapeutic resistance and proposes future directions for research in this exciting and rapidly evolving field.
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Affiliation(s)
- Ting Wang
- Department of Clinical Research, Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 610041, China
| | - Mengjie He
- Laboratory Medicine Center, Sichuan Provincial Maternity and Child Health Care Hospital, Affiliated Women's and Children's Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, 610041, China
| | - Xudong Zhang
- Department of Clinical Research, Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 610041, China
| | - Zhixun Guo
- Department of Clinical Research, Sichuan Clinical Research Center for Cancer, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 610041, China
| | - Pinghan Wang
- Laboratory Medicine Center, Sichuan Provincial Maternity and Child Health Care Hospital, Affiliated Women's and Children's Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, 610041, China.
| | - Fangyi Long
- Laboratory Medicine Center, Sichuan Provincial Maternity and Child Health Care Hospital, Affiliated Women's and Children's Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, 610041, China.
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7
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Park SLL, Ramírez-Jarquín UN, Shahani N, Rivera O, Sharma M, Joshi PS, Hansalia A, Dagar S, McManus FP, Thibault P, Subramaniam S. SUMO modifies GβL and mediates mTOR signaling. J Biol Chem 2024; 300:105778. [PMID: 38395307 PMCID: PMC10982569 DOI: 10.1016/j.jbc.2024.105778] [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: 09/08/2023] [Revised: 01/25/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) signaling is influenced by multiple regulatory proteins and post-translational modifications; however, underlying mechanisms remain unclear. Here, we report a novel role of small ubiquitin-like modifier (SUMO) in mTOR complex assembly and activity. By investigating the SUMOylation status of core mTOR components, we observed that the regulatory subunit, GβL (G protein β-subunit-like protein, also known as mLST8), is modified by SUMO1, 2, and 3 isoforms. Using mutagenesis and mass spectrometry, we identified that GβL is SUMOylated at lysine sites K86, K215, K245, K261, and K305. We found that SUMO depletion reduces mTOR-Raptor (regulatory protein associated with mTOR) and mTOR-Rictor (rapamycin-insensitive companion of mTOR) complex formation and diminishes nutrient-induced mTOR signaling. Reconstitution with WT GβL but not SUMOylation-defective KR mutant GβL promotes mTOR signaling in GβL-depleted cells. Taken together, we report for the very first time that SUMO modifies GβL, influences the assembly of mTOR protein complexes, and regulates mTOR activity.
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Affiliation(s)
| | | | - Neelam Shahani
- Department of Neuroscience, The Wertheim UF Scripps Institute, Jupiter, Florida, USA
| | - Oscar Rivera
- Department of Neuroscience, The Wertheim UF Scripps Institute, Jupiter, Florida, USA
| | - Manish Sharma
- Department of Neuroscience, The Wertheim UF Scripps Institute, Jupiter, Florida, USA
| | | | - Aayushi Hansalia
- Department of Neuroscience, The Wertheim UF Scripps Institute, Jupiter, Florida, USA
| | - Sunayana Dagar
- Department of Neuroscience, The Wertheim UF Scripps Institute, Jupiter, Florida, USA
| | - Francis P McManus
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada; Department of Chemistry, Université de Montréal, Montréal, Quebec, Canada
| | - Srinivasa Subramaniam
- Department of Neuroscience, The Wertheim UF Scripps Institute, Jupiter, Florida, USA; The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, California, USA; Norman Fixel Institute for Neurological Diseases, Gainesville, Florida, USA.
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8
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Myburgh E, Geoghegan V, Alves-Ferreira EV, Nievas YR, Grewal JS, Brown E, McLuskey K, Mottram JC. TORC1 is an essential regulator of nutrient-controlled proliferation and differentiation in Leishmania. EMBO Rep 2024; 25:1075-1105. [PMID: 38396206 PMCID: PMC10933368 DOI: 10.1038/s44319-024-00084-y] [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: 01/16/2023] [Revised: 01/19/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Leishmania parasites undergo differentiation between various proliferating and non-dividing forms to adapt to changing host environments. The mechanisms that link environmental cues with the parasite's developmental changes remain elusive. Here, we report that Leishmania TORC1 is a key environmental sensor for parasite proliferation and differentiation in the sand fly-stage promastigotes and for replication of mammalian-stage amastigotes. We show that Leishmania RPTOR1, interacts with TOR1 and LST8, and identify new parasite-specific proteins that interact in this complex. We investigate TORC1 function by conditional deletion of RPTOR1, where under nutrient-rich conditions RPTOR1 depletion results in decreased protein synthesis and growth, G1 cell cycle arrest and premature differentiation from proliferative promastigotes to non-dividing mammalian-infective metacyclic forms. These parasites are unable to respond to nutrients to differentiate into proliferative retroleptomonads, which are required for their blood-meal induced amplification in sand flies and enhanced mammalian infectivity. We additionally show that RPTOR1-/- metacyclic promastigotes develop into amastigotes but do not proliferate in the mammalian host to cause pathology. RPTOR1-dependent TORC1 functionality represents a critical mechanism for driving parasite growth and proliferation.
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Affiliation(s)
- Elmarie Myburgh
- York Biomedical Research Institute, Hull York Medical School, University of York, York, YO10 5DD, UK.
| | - Vincent Geoghegan
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Eliza Vc Alves-Ferreira
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Y Romina Nievas
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Jaspreet S Grewal
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Elaine Brown
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
| | - Karen McLuskey
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, YO10 5DD, UK
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9
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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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10
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Liu Y, Zhang M, Jang H, Nussinov R. The allosteric mechanism of mTOR activation can inform bitopic inhibitor optimization. Chem Sci 2024; 15:1003-1017. [PMID: 38239681 PMCID: PMC10793652 DOI: 10.1039/d3sc04690g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024] Open
Abstract
mTOR serine/threonine kinase is a cornerstone in the PI3K/AKT/mTOR pathway. Yet, the detailed mechanism of activation of its catalytic core is still unresolved, likely due to mTOR complexes' complexity. Its dysregulation was implicated in cancer and neurodevelopmental disorders. Using extensive molecular dynamics (MD) simulations and compiled published experimental data, we determine exactly how mTOR's inherent motifs can control the conformational changes in the kinase domain, thus kinase activity. We also chronicle the critical regulation by the unstructured negative regulator domain (NRD). When positioned inside the catalytic cleft (NRD IN state), mTOR tends to adopt a deep and closed catalytic cleft. This is primarily due to the direct interaction with the FKBP-rapamycin binding (FRB) domain which restricts it, preventing substrate access. Conversely, when outside the catalytic cleft (NRD OUT state), mTOR favors an open conformation, exposing the substrate-binding site on the FRB domain. We further show how an oncogenic mutation (L2427R) promotes shifting the mTOR ensemble toward the catalysis-favored state. Collectively, we extend mTOR's "active-site restriction" mechanism and clarify mutation action. In particular, our mechanism suggests that RMC-5552 (RMC-6272) bitopic inhibitors may benefit from adjustment of the (PEG8) linker length when targeting certain mTOR variants. In the cryo-EM mTOR/RMC-5552 structure, the distance between the allosteric and orthosteric inhibitors is ∼22.7 Å. With a closed catalytic cleft, this linker bridges the sites. However, in our activation mechanism, in the open cleft it expands to ∼24.7 Å, offering what we believe to be the first direct example of how discovering an activation mechanism can potentially increase the affinity of inhibitors targeting mutants.
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Affiliation(s)
- Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University Tel Aviv 69978 Israel
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11
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Davarinejad H, Arvanitis-Vigneault A, Nygard D, Lavallée-Adam M, Couture JF. Modus operandi: Chromatin recognition by α-helical histone readers. Structure 2024; 32:8-17. [PMID: 37922903 DOI: 10.1016/j.str.2023.10.008] [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: 07/20/2023] [Revised: 09/25/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023]
Abstract
Histone reader domains provide a mechanism for sensing states of coordinated nuclear processes marked by histone proteins' post-translational modifications (PTMs). Among a growing number of discovered histone readers, the 14-3-3s, ankyrin repeat domains (ARDs), tetratricopeptide repeats (TPRs), bromodomains (BRDs), and HEAT domains are a group of domains using various mechanisms to recognize unmodified or modified histones, yet they all are composed of an α-helical fold. In this review, we compare how these readers fold to create protein domains that are very diverse in their tertiary structures, giving rise to intriguing peptide binding mechanisms resulting in vastly different footprints of their targets.
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Affiliation(s)
- Hossein Davarinejad
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Alexis Arvanitis-Vigneault
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Dallas Nygard
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Mathieu Lavallée-Adam
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Jean-François Couture
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada.
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12
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Lin Y, Wu Y, Zhang Q, Tu X, Chen S, Pan J, Xu N, Lin M, She P, Niu G, Chen Y, Li H. RPTOR blockade suppresses brain metastases of NSCLC by interfering the ceramide metabolism via hijacking YY1 binding. J Exp Clin Cancer Res 2024; 43:1. [PMID: 38163890 PMCID: PMC10759737 DOI: 10.1186/s13046-023-02874-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/29/2023] [Indexed: 01/03/2024] Open
Abstract
BACKGROUND Ceramide metabolism is crucial in the progress of brain metastasis (BM). However, it remains unexplored whether targeting ceramide metabolism may arrest BM. METHODS RNA sequencing was applied to screen different genes in primary and metastatic foci and whole-exome sequencing (WES) to seek crucial abnormal pathway in BM + and BM-patients. Cellular arrays were applied to analyze the permeability of blood-brain barrier (BBB) and the activation or inhibition of pathway. Database and Co-Immunoprecipitation (Co-IP) assay were adopted to verify the protein-protein interaction. Xenograft and zebrafish model were further employed to verify the cellular results. RESULTS RNA sequencing and WES reported the involvement of RPTOR and ceramide metabolism in BM progress. RPTOR was significantly upregulated in BM foci and increased the permeability of BBB, while RPTOR deficiency attenuated the cell invasiveness and protected extracellular matrix. Exogenous RPTOR boosted the SPHK2/S1P/STAT3 cascades by binding YY1, in which YY1 bound to the regions of SPHK2 promoter (at -353 ~ -365 nt), further promoting the expression of SPHK2. The latter was rescued by YY1 RNAi. Xenograft and zebrafish model showed that RPTOR blockade suppressed BM of non-small cell lung cancer (NSCLC) and impaired the SPHK2/S1P/STAT3 pathway. CONCLUSION RPTOR is a key driver gene in the brain metastasis of lung cancer, which signifies that RPTOR blockade may serve as a promising therapeutic candidate for clinical application.
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Affiliation(s)
- Ying Lin
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China
| | - Yun Wu
- Department of General Practice Medicine, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Qiangzu Zhang
- The High Performance Computing Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, 100095, China
| | - Xunwei Tu
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China
| | - Sufang Chen
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China
| | - Junfan Pan
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China
| | - Nengluan Xu
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China
| | - Ming Lin
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China
| | - Peiwei She
- The Centre for Experimental Research in Clinical Medicine, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China
| | - Gang Niu
- The High Performance Computing Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, 100095, China.
| | - Yusheng Chen
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China.
| | - Hongru Li
- Department of Respiratory and Critical Care Medicine, Shengli Clinical Medical College, Fujian Medical University, Fujian Provincial Hospital, Fuzhou, 350001, Fujian, China.
- Fujian Provincial Key Laboratory of Medical Big Data Engineering, Fujian Provincial Hospital, Shengli Clinical College of Fujian Medical University, Fuzhou, 350001, Fujian, China.
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13
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López-Perrote A, Serna M, Llorca O. Maturation and Assembly of mTOR Complexes by the HSP90-R2TP-TTT Chaperone System: Molecular Insights and Mechanisms. Subcell Biochem 2024; 104:459-483. [PMID: 38963496 DOI: 10.1007/978-3-031-58843-3_17] [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
The mechanistic target of rapamycin (mTOR) is a master regulator of cell growth and metabolism, integrating environmental signals to regulate anabolic and catabolic processes, regulating lipid synthesis, growth factor-induced cell proliferation, cell survival, and migration. These activities are performed as part of two distinct complexes, mTORC1 and mTORC2, each with specific roles. mTORC1 and mTORC2 are elaborated dimeric structures formed by the interaction of mTOR with specific partners. mTOR functions only as part of these large complexes, but their assembly and activation require a dedicated and sophisticated chaperone system. mTOR folding and assembly are temporarily separated with the TELO2-TTI1-TTI2 (TTT) complex assisting the cotranslational folding of mTOR into a native conformation. Matured mTOR is then transferred to the R2TP complex for assembly of active mTORC1 and mTORC2 complexes. R2TP works in concert with the HSP90 chaperone to promote the incorporation of additional subunits to mTOR and dimerization. This review summarizes our current knowledge on how the HSP90-R2TP-TTT chaperone system facilitates the maturation and assembly of active mTORC1 and mTORC2 complexes, discussing interactions, structures, and mechanisms.
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Affiliation(s)
- Andrés López-Perrote
- Spanish National Cancer Research Centre (CNIO), Structural Biology Programme, Melchor Fernández Almagro 3, Madrid, Spain.
| | - Marina Serna
- Spanish National Cancer Research Centre (CNIO), Structural Biology Programme, Melchor Fernández Almagro 3, Madrid, Spain
| | - Oscar Llorca
- Spanish National Cancer Research Centre (CNIO), Structural Biology Programme, Melchor Fernández Almagro 3, Madrid, Spain.
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14
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Kohyanagi N, Kitamura N, Ikeda S, Shibutani S, Sato K, Ohama T. PP2A inhibitor SET promotes mTORC1 and Bmi1 signaling through Akt activation and maintains the colony-formation ability of cancer cells. J Biol Chem 2024; 300:105584. [PMID: 38141761 PMCID: PMC10826185 DOI: 10.1016/j.jbc.2023.105584] [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: 06/23/2023] [Revised: 11/19/2023] [Accepted: 12/07/2023] [Indexed: 12/25/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is an essential tumor suppressor, with its activity often hindered in cancer cells by endogenous PP2A inhibitory proteins like SE translocation (SET). SET/PP2A axis plays a pivotal role in the colony-formation ability of cancer cells and the stabilization of c-Myc and E2F1 proteins implicated in this process. However, in osteosarcoma cell line HOS, SET knock-down (KD) suppresses the colony-formation ability without affecting c-Myc and E2F1. This study aimed to unravel the molecular mechanism through which SET enhances the colony-formation ability of HOS cells and determine if it is generalized to other cancer cells. Transcriptome analysis unveiled that SET KD suppressed mTORC1 signaling. SET KD inhibited Akt phosphorylation, an upstream kinase for mTORC1. PP2A inhibitor blocked SET KD-mediated decrease in phosphorylation of Akt and a mTORC1 substrate p70S6K. A constitutively active Akt restored decreased colony-formation ability by SET KD, indicating the SET/PP2A/Akt/mTORC1 axis. Additionally, enrichment analysis highlighted that Bmi-1, a polycomb group protein, is affected by SET KD. SET KD decreased Bmi-1 protein by Akt inhibition but not by mTORC1 inhibition, and exogenous Bmi-1 expression rescued the reduced colony formation by SET KD. Four out of eight cancer cell lines exhibited decreased Bmi-1 by SET KD. Further analysis of these cell lines revealed that Myc activity plays a role in SET KD-mediated Bmi-1 degradation. These findings provide new insights into the molecular mechanism of SET-regulated colony-formation ability, which involved Akt-mediated activation of mTORC1/p70S6K and Bmi-1 signaling.
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Affiliation(s)
- Naoki Kohyanagi
- Laboratory of Veterinary Pharmacology, Yamaguchi University Joint Graduate School of Veterinary Medicine, Yamaguchi, Japan
| | - Nao Kitamura
- Laboratory of Veterinary Pharmacology, Yamaguchi University Joint Graduate School of Veterinary Medicine, Yamaguchi, Japan
| | - Shunta Ikeda
- Laboratory of Veterinary Pharmacology, Yamaguchi University Joint Graduate School of Veterinary Medicine, Yamaguchi, Japan
| | - Shusaku Shibutani
- Laboratory of Veterinary Hygiene, Yamaguchi University Joint Graduate School of Veterinary Medicine, Yamaguchi, Japan
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology, Yamaguchi University Joint Graduate School of Veterinary Medicine, Yamaguchi, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology, Yamaguchi University Joint Graduate School of Veterinary Medicine, Yamaguchi, Japan.
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15
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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: 16] [Impact Index Per Article: 16.0] [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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16
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Yu FY, Zheng K, Wu YF, Gao SW, Weng QY, Zhu C, Wu YP, Li M, Qin ZN, Lou JF, Chen ZH, Ying SM, Shen HH, Li W. Rapamycin Exacerbates Staphylococcus aureus Pneumonia by Inhibiting mTOR-RPS6 in Macrophages. J Inflamm Res 2023; 16:5715-5728. [PMID: 38053607 PMCID: PMC10695130 DOI: 10.2147/jir.s434483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/17/2023] [Indexed: 12/07/2023] Open
Abstract
Purpose This study aimed to explore the effect of Rapamycin (Rapa) in Staphylococcus aureus (S. aureus) pneumonia and clarify its possible mechanism. Methods We investigated the effects of Rapa on S. aureus pneumonia in mouse models and in macrophages cultured in vitro. Two possible mechanisms were investigated: the mTOR-RPS6 pathway phosphorylation and phagocytosis. Furthermore, for the mechanism verification in vivo, mice with specific Mtor knockout in myeloid cells were constructed for pneumonia models. Results Rapa exacerbated S. aureus pneumonia in mouse models, promoting chemokines secretion and inflammatory cells infiltration in lung. In vitro, Rapa upregulated the secretion of chemokines and cytokines in macrophages induced by S. aureus. Mechanistically, the mTOR-ribosomal protein S6 (RPS6) pathway in macrophages was phosphorylated in response to S. aureus infection, and the inhibition of RPS6 phosphorylation upregulated the inflammation level. However, Rapa did not increase the phagocytic activity. Accordingly, mice with specific Mtor knockout in myeloid cells experienced more severe S. aureus pneumonia. Conclusion Rapa exacerbates S. aureus pneumonia by increasing the inflammatory levels of macrophages. Inhibition of mTOR-RPS6 pathway upregulates the expression of cytokines and chemokines in macrophages, thus increases inflammatory cells infiltration and exacerbates tissue damage.
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Affiliation(s)
- Fang-Yi Yu
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Kua Zheng
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Yin-Fang Wu
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Shen-Wei Gao
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Qing-Yu Weng
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Chen Zhu
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Yan-Ping Wu
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Miao Li
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Zhong-Nan Qin
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Jia-Fei Lou
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Zhi-Hua Chen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Song-Min Ying
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Hua-Hao Shen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
| | - Wen Li
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China
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17
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Welters A, Leiter SM, Bachmann N, Bergmann C, Hoermann H, Korsch E, Meissner T, Payne F, Williams R, Hussain K, Semple RK, Kummer S. An expanded clinical spectrum of hypoinsulinaemic hypoketotic hypoglycaemia. Orphanet J Rare Dis 2023; 18:360. [PMID: 37974153 PMCID: PMC10652530 DOI: 10.1186/s13023-023-02954-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 10/16/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Hypoketotic hypoglycaemia with suppressed plasma fatty acids and detectable insulin suggests congenital hyperinsulinism (CHI). Severe hypoketotic hypoglycaemia mimicking hyperinsulinism but without detectable insulin has recently been described in syndromic individuals with mosaic genetic activation of post-receptor insulin signalling. We set out to expand understanding of this entity focusing on metabolic phenotypes. METHODS Metabolic profiling, candidate gene and exome sequencing were performed in six infants with hypoketotic, hypoinsulinaemic hypoglycaemia, with or without syndromic features. Additional signalling studies were carried out in dermal fibroblasts from two individuals. RESULTS Two infants had no syndromic features. One was mistakenly diagnosed with CHI. One had mild features of megalencephaly-capillary malformation-polymicrogyria (MCAP) syndrome, one had non-specific macrosomia, and two had complex syndromes. All required intensive treatment to maintain euglycaemia, with CHI-directed therapies being ineffective. Pathogenic PIK3CA variants were found in two individuals - de novo germline c.323G>A (p.Arg108His) in one non-syndromic infant and postzygotic mosaic c.2740G>A (p.Gly914Arg) in the infant with MCAP. No causal variants were proven in the other individuals despite extensive investigation, although rare variants in mTORC components were identified in one. No increased PI3K signalling in fibroblasts of two individuals was seen. CONCLUSIONS We expand the spectrum of PI3K-related hypoinsulinaemic hypoketotic hypoglycaemia. We demonstrate that pathogenic germline variants activating post-insulin-receptor signalling may cause non-syndromic hypoinsulinaemic hypoketotic hypoglycaemia closely resembling CHI. This distinct biochemical footprint should be sought and differentiated from CHI in infantile hypoglycaemia. To facilitate adoption of this differential diagnosis, we propose the term "pseudohyperinsulinism".
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Affiliation(s)
- Alena Welters
- Department of General Paediatrics, Neonatology and Paediatric Cardiology, Medical Faculty, University Children's Hospital, Heinrich-Heine University, Düsseldorf, Germany
| | - Sarah M Leiter
- MRC Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Nadine Bachmann
- Medizinische Genetik Mainz, Limbach Genetics, Mainz, Germany
| | | | - Henrike Hoermann
- Department of General Paediatrics, Neonatology and Paediatric Cardiology, Medical Faculty, University Children's Hospital, Heinrich-Heine University, Düsseldorf, Germany
| | - Eckhard Korsch
- Paediatric Endocrinology, Children's Hospital, Amsterdamer Straße 59, Cologne, Germany
| | - Thomas Meissner
- Department of General Paediatrics, Neonatology and Paediatric Cardiology, Medical Faculty, University Children's Hospital, Heinrich-Heine University, Düsseldorf, Germany
| | - Felicity Payne
- Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - Rachel Williams
- Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - Khalid Hussain
- Department of Paediatric Medicine, Division of Endocrinology and Diabetes, Sidra Medicine, Education City North Campus, Doha, Qatar
| | - Robert K Semple
- MRC Metabolic Diseases Unit, Wellcome-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
- MRC Human Genetics Unit, Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
| | - Sebastian Kummer
- Department of General Paediatrics, Neonatology and Paediatric Cardiology, Medical Faculty, University Children's Hospital, Heinrich-Heine University, Düsseldorf, Germany.
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18
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Foltman M, Sanchez-Diaz A. TOR Complex 1: Orchestrating Nutrient Signaling and Cell Cycle Progression. Int J Mol Sci 2023; 24:15745. [PMID: 37958727 PMCID: PMC10647266 DOI: 10.3390/ijms242115745] [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: 09/01/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
The highly conserved TOR signaling pathway is crucial for coordinating cellular growth with the cell cycle machinery in eukaryotes. One of the two TOR complexes in budding yeast, TORC1, integrates environmental cues and promotes cell growth. While cells grow, they need to copy their chromosomes, segregate them in mitosis, divide all their components during cytokinesis, and finally physically separate mother and daughter cells to start a new cell cycle apart from each other. To maintain cell size homeostasis and chromosome stability, it is crucial that mechanisms that control growth are connected and coordinated with the cell cycle. Successive periods of high and low TORC1 activity would participate in the adequate cell cycle progression. Here, we review the known molecular mechanisms through which TORC1 regulates the cell cycle in the budding yeast Saccharomyces cerevisiae that have been extensively used as a model organism to understand the role of its mammalian ortholog, mTORC1.
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Affiliation(s)
- Magdalena Foltman
- Mechanisms and Regulation of Cell Division Research Unit, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, 39011 Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, 39011 Santander, Spain
| | - Alberto Sanchez-Diaz
- Mechanisms and Regulation of Cell Division Research Unit, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, 39011 Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, 39011 Santander, Spain
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He L, Chen J, Deng P, Huang S, Liu P, Wang C, Huang X, Li Y, Chen B, Shi D, Xiao Y, Chen X, Ouyang Y, Song L, Lin C. Lysosomal cyst(e)ine storage potentiates tolerance to oxidative stress in cancer cells. Mol Cell 2023; 83:3502-3519.e11. [PMID: 37751742 DOI: 10.1016/j.molcel.2023.08.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 07/17/2023] [Accepted: 08/30/2023] [Indexed: 09/28/2023]
Abstract
Cyst(e)ine is a key precursor for the synthesis of glutathione (GSH), which protects cancer cells from oxidative stress. Cyst(e)ine is stored in lysosomes, but its role in redox regulation is unclear. Here, we show that breast cancer cells upregulate major facilitator superfamily domain containing 12 (MFSD12) to increase lysosomal cyst(e)ine storage, which is released by cystinosin (CTNS) to maintain GSH levels and buffer oxidative stress. We find that mTORC1 regulates MFSD12 by directly phosphorylating residue T254, while mTORC1 inhibition enhances lysosome acidification that activates CTNS. This switch modulates lysosomal cyst(e)ine levels in response to oxidative stress, fine-tuning redox homeostasis to enhance cell fitness. MFSD12-T254A mutant inhibits MFSD12 function and suppresses tumor progression. Moreover, MFSD12 overexpression correlates with poor neoadjuvant chemotherapy response and prognosis in breast cancer patients. Our findings reveal the critical role of lysosomal cyst(e)ine storage in adaptive redox homeostasis and suggest that MFSD12 is a potential therapeutic target.
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Affiliation(s)
- Lixin He
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Jinxin Chen
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Pinwei Deng
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Shumei Huang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Pian Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chanjuan Wang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Xinjian Huang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Yue Li
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Boyu Chen
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Dongni Shi
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Yunyun Xiao
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Xiangfu Chen
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Ying Ouyang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Libing Song
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Institute of Oncology, Tumor Hospital, Guangzhou Medical University, Guangzhou 510080, China
| | - Chuyong Lin
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Guangdong Esophageal Cancer Institute, Guangzhou 510060, China.
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20
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Zhang F, Cheng T, Zhang SX. Mechanistic target of rapamycin (mTOR): a potential new therapeutic target for rheumatoid arthritis. Arthritis Res Ther 2023; 25:187. [PMID: 37784141 PMCID: PMC10544394 DOI: 10.1186/s13075-023-03181-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 09/25/2023] [Indexed: 10/04/2023] Open
Abstract
Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic synovitis and bone destruction. Proinflammatory cytokines activate pathways of immune-mediated inflammation, which aggravates RA. The mechanistic target of rapamycin (mTOR) signaling pathway associated with RA connects immune and metabolic signals, which regulates immune cell proliferation and differentiation, macrophage polarization and migration, antigen presentation, and synovial cell activation. Therefore, therapy strategies targeting mTOR have become an important direction of current RA treatment research. In the current review, we summarize the biological functions of mTOR, its regulatory effects on inflammation, and the curative effects of mTOR inhibitors in RA, thus providing references for the development of RA therapeutic targets and new drugs.
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Affiliation(s)
- Fen Zhang
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Xinghualing District, Taiyuan, 030001, Shanxi Province, China
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
| | - Ting Cheng
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Xinghualing District, Taiyuan, 030001, Shanxi Province, China
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
| | - Sheng-Xiao Zhang
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Xinghualing District, Taiyuan, 030001, Shanxi Province, China.
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China.
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China.
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21
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Linde-Garelli KY, Rogala KB. Structural mechanisms of the mTOR pathway. Curr Opin Struct Biol 2023; 82:102663. [PMID: 37572585 DOI: 10.1016/j.sbi.2023.102663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/01/2023] [Accepted: 07/07/2023] [Indexed: 08/14/2023]
Abstract
The mTOR signaling pathway is essential for regulating cell growth and mammalian metabolism. The mTOR kinase forms two complexes, mTORC1 and mTORC2, which respond to external stimuli and regulate differential downstream targets. Cellular membrane-associated translocation mediates function and assembly of the mTOR complexes, and recent structural studies have begun uncovering the molecular basis by which the mTOR pathway (1) regulates signaling inputs, (2) recruits substrates, (3) localizes to biological membranes, and (4) becomes activated. Moreover, indications of dysregulated mTOR signaling are implicated in a wide range of diseases and an increasingly comprehensive understanding of structural mechanisms is driving novel translational development.
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Affiliation(s)
- Karen Y Linde-Garelli
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Kacper B Rogala
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA.
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22
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Shin S, Han MJ, Jedrychowski MP, Zhang Z, Shokat KM, Plas DR, Dephoure N, Yoon SO. mTOR inhibition reprograms cellular proteostasis by regulating eIF3D-mediated selective mRNA translation and promotes cell phenotype switching. Cell Rep 2023; 42:112868. [PMID: 37494188 PMCID: PMC10528759 DOI: 10.1016/j.celrep.2023.112868] [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: 12/05/2022] [Revised: 05/31/2023] [Accepted: 07/11/2023] [Indexed: 07/28/2023] Open
Abstract
Cells maintain and dynamically change their proteomes according to the environment and their needs. Mechanistic target of rapamycin (mTOR) is a key regulator of proteostasis, homeostasis of the proteome. Thus, dysregulation of mTOR leads to changes in proteostasis and the consequent progression of diseases, including cancer. Based on the physiological and clinical importance of mTOR signaling, we investigated mTOR feedback signaling, proteostasis, and cell fate. Here, we reveal that mTOR targeting inhibits eIF4E-mediated cap-dependent translation, but feedback signaling activates a translation initiation factor, eukaryotic translation initiation factor 3D (eIF3D), to sustain alternative non-canonical translation mechanisms. Importantly, eIF3D-mediated protein synthesis enables cell phenotype switching from proliferative to more migratory. eIF3D cooperates with mRNA-binding proteins such as heterogeneous nuclear ribonucleoprotein F (hnRNPF), heterogeneous nuclear ribonucleoprotein K (hnRNPK), and Sjogren syndrome antigen B (SSB) to support selective mRNA translation following mTOR inhibition, which upregulates and activates proteins involved in insulin receptor (INSR)/insulin-like growth factor 1 receptor (IGF1R)/insulin receptor substrate (IRS) and interleukin 6 signal transducer (IL-6ST)/Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling. Our study highlights the mechanisms by which cells establish the dynamic change of proteostasis and the resulting phenotype switch.
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Affiliation(s)
- Sejeong Shin
- Department of Physiology and Biophysics, University of Illinois College of Medicine at Chicago, Chicago, IL 60612, USA
| | - Min-Joon Han
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | | - Ziyang Zhang
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Kevan M Shokat
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA
| | - David R Plas
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Noah Dephoure
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10021, USA
| | - Sang-Oh Yoon
- Department of Physiology and Biophysics, University of Illinois College of Medicine at Chicago, Chicago, IL 60612, USA.
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23
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Wang YJ, Valotteau C, Aimard A, Villanueva L, Kostrz D, Follenfant M, Strick T, Chames P, Rico F, Gosse C, Limozin L. Combining DNA scaffolds and acoustic force spectroscopy to characterize individual protein bonds. Biophys J 2023; 122:2518-2530. [PMID: 37290437 PMCID: PMC10323022 DOI: 10.1016/j.bpj.2023.05.004] [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: 08/07/2022] [Revised: 12/13/2022] [Accepted: 05/03/2023] [Indexed: 06/10/2023] Open
Abstract
Single-molecule data are of great significance in biology, chemistry, and medicine. However, new experimental tools to characterize, in a multiplexed manner, protein bond rupture under force are still needed. Acoustic force spectroscopy is an emerging manipulation technique which generates acoustic waves to apply force in parallel on multiple microbeads tethered to a surface. We here exploit this configuration in combination with the recently developed modular junctured-DNA scaffold that has been designed to study protein-protein interactions at the single-molecule level. By applying repetitive constant force steps on the FKBP12-rapamycin-FRB complex, we measure its unbinding kinetics under force at the single-bond level. Special efforts are made in analyzing the data to identify potential pitfalls. We propose a calibration method allowing in situ force determination during the course of the unbinding measurement. We compare our results with well-established techniques, such as magnetic tweezers, to ensure their accuracy. We also apply our strategy to study the force-dependent rupture of a single-domain antibody with its antigen. Overall, we get a good agreement with the published parameters that have been obtained at zero force and population level. Thus, our technique offers single-molecule precision for multiplexed measurements of interactions of biotechnological and medical interest.
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Affiliation(s)
- Yong Jian Wang
- Aix-Marseille Université, CNRS, INSERM, Laboratoire Adhesion et Inflammation, Turing Centre for Living systems, Marseille, France.
| | - Claire Valotteau
- Aix-Marseille Université, CNRS, INSERM, Laboratoire Adhesion et Inflammation, Turing Centre for Living systems, Marseille, France
| | - Adrien Aimard
- Aix-Marseille Université, CNRS, INSERM, Institut Paoli-Calmettes, Centre de Recherche en Cancerologie de Marseille, Marseille, France
| | - Lorenzo Villanueva
- Aix-Marseille Université, CNRS, INSERM, Laboratoire Adhesion et Inflammation, Turing Centre for Living systems, Marseille, France
| | - Dorota Kostrz
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Maryne Follenfant
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Terence Strick
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Patrick Chames
- Aix-Marseille Université, CNRS, INSERM, Institut Paoli-Calmettes, Centre de Recherche en Cancerologie de Marseille, Marseille, France
| | - Felix Rico
- Aix-Marseille Université, CNRS, INSERM, Laboratoire Adhesion et Inflammation, Turing Centre for Living systems, Marseille, France
| | - Charlie Gosse
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France.
| | - Laurent Limozin
- Aix-Marseille Université, CNRS, INSERM, Laboratoire Adhesion et Inflammation, Turing Centre for Living systems, Marseille, France.
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24
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Mannick JB, Lamming DW. Targeting the biology of aging with mTOR inhibitors. NATURE AGING 2023; 3:642-660. [PMID: 37142830 PMCID: PMC10330278 DOI: 10.1038/s43587-023-00416-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 04/07/2023] [Indexed: 05/06/2023]
Abstract
Inhibition of the protein kinase mechanistic target of rapamycin (mTOR) with the Food and Drug Administration (FDA)-approved therapeutic rapamycin promotes health and longevity in diverse model organisms. More recently, specific inhibition of mTORC1 to treat aging-related conditions has become the goal of basic and translational scientists, clinicians and biotechnology companies. Here, we review the effects of rapamycin on the longevity and survival of both wild-type mice and mouse models of human diseases. We discuss recent clinical trials that have explored whether existing mTOR inhibitors can safely prevent, delay or treat multiple diseases of aging. Finally, we discuss how new molecules may provide routes to the safer and more selective inhibition of mTOR complex 1 (mTORC1) in the decade ahead. We conclude by discussing what work remains to be done and the questions that will need to be addressed to make mTOR inhibitors part of the standard of care for diseases of aging.
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Affiliation(s)
| | - Dudley W Lamming
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
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25
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Sharp ZD, Strong R. Rapamycin, the only drug that has been consistently demonstrated to increase mammalian longevity. An update. Exp Gerontol 2023; 176:112166. [PMID: 37011714 PMCID: PMC10868408 DOI: 10.1016/j.exger.2023.112166] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023]
Affiliation(s)
- Zelton Dave Sharp
- Department of Molecular Medicine and Institute of Biotechnology, San Antonio, TX, United States of America; Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States of America; Mays Cancer Center, San Antonio, TX, United States of America.
| | - Randy Strong
- Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States of America; Department of Pharmacology, UT Health, San Antonio, TX, United States of America; Research Service of the South Texas Veterans Health Care System, San Antonio, TX 78229, United States of America.
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26
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Valluri A, Wellman J, McCallister CL, Brown KC, Lawrence L, Russell R, Jensen J, Denvir J, Valentovic MA, Denning KL, Salisbury TB. mTOR Regulation of N-Myc Downstream Regulated 1 (NDRG1) Phosphorylation in Clear Cell Renal Cell Carcinoma. Int J Mol Sci 2023; 24:9364. [PMID: 37298315 PMCID: PMC10253553 DOI: 10.3390/ijms24119364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/17/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) kinase is a component of two signaling complexes that are known as mTOR complex 1 (mTORC1) and mTORC2. We sought to identify mTOR-phosphorylated proteins that are differently expressed in clinically resected clear cell renal cell carcinoma (ccRCC) relative to pair-matched normal renal tissue. Using a proteomic array, we found N-Myc Downstream Regulated 1 (NDRG1) showed the greatest increase (3.3-fold) in phosphorylation (on Thr346) in ccRCC. This was associated with an increase in total NDRG1. RICTOR is a required subunit in mTORC2, and its knockdown decreased total and phospho-NDRG1 (Thr346) but not NDRG1 mRNA. The dual mTORC1/2 inhibitor, Torin 2, significantly reduced (by ~100%) phospho-NDRG1 (Thr346). Rapamycin is a selective mTORC1 inhibitor that had no effect on the levels of total NDRG1 or phospho-NDRG1 (Thr346). The reduction in phospho-NDRG1 (Thr346) due to the inhibition of mTORC2 corresponded with a decrease in the percentage of live cells, which was correlated with an increase in apoptosis. Rapamycin had no effect on ccRCC cell viability. Collectively, these data show that mTORC2 mediates the phosphorylation of NDRG1 (Thr346) in ccRCC. We hypothesize that RICTOR and mTORC2-mediated phosphorylation of NDRG1 (Thr346) promotes the viability of ccRCC cells.
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Affiliation(s)
- Anisha Valluri
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA; (A.V.); (J.W.); (C.L.M.); (K.C.B.); (J.D.); (M.A.V.)
| | - Jessica Wellman
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA; (A.V.); (J.W.); (C.L.M.); (K.C.B.); (J.D.); (M.A.V.)
| | - Chelsea L. McCallister
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA; (A.V.); (J.W.); (C.L.M.); (K.C.B.); (J.D.); (M.A.V.)
| | - Kathleen C. Brown
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA; (A.V.); (J.W.); (C.L.M.); (K.C.B.); (J.D.); (M.A.V.)
| | - Logan Lawrence
- Cabell Huntington Hospital Laboratory, Department of Pathology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA; (L.L.); (R.R.); (K.L.D.)
| | - Rebecca Russell
- Cabell Huntington Hospital Laboratory, Department of Pathology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA; (L.L.); (R.R.); (K.L.D.)
| | - James Jensen
- Edwards Comprehensive Cancer Center, Department of Oncology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA;
| | - James Denvir
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA; (A.V.); (J.W.); (C.L.M.); (K.C.B.); (J.D.); (M.A.V.)
| | - Monica A. Valentovic
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA; (A.V.); (J.W.); (C.L.M.); (K.C.B.); (J.D.); (M.A.V.)
| | - Krista L. Denning
- Cabell Huntington Hospital Laboratory, Department of Pathology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA; (L.L.); (R.R.); (K.L.D.)
| | - Travis B. Salisbury
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA; (A.V.); (J.W.); (C.L.M.); (K.C.B.); (J.D.); (M.A.V.)
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27
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Ingargiola C, Jéhanno I, Forzani C, Marmagne A, Broutin J, Clément G, Leprince AS, Meyer C. The Arabidopsis Target of Rapamycin (TOR) kinase regulates ammonium assimilation and glutamine metabolism. PLANT PHYSIOLOGY 2023:kiad216. [PMID: 37042394 DOI: 10.1093/plphys/kiad216] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/01/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
In eukaryotes, Target of Rapamycin (TOR) is a well conserved kinase that controls cell metabolism and growth in response to nutrients and environmental factors. Nitrogen (N) is an essential element for plants, and TOR functions as a crucial N and amino acid sensor in animals and yeast. However, knowledge on the connections between TOR and the overall N metabolism and assimilation in plants is still limited. In this study, we investigated the regulation of TOR in Arabidopsis (Arabidopsis thaliana) by the N source as well as the impact of TOR deficiency on N metabolism. Inhibition of TOR globally decreased ammonium uptake while triggering a massive accumulation of amino acids, such as Gln, but also of polyamines. Consistently, TOR complex mutants were hypersensitive to Gln. We also showed that the glutamine synthetase inhibitor glufosinate abolishes Gln accumulation resulting from TOR inhibition and improves the growth of TOR complex mutants. These results suggest that a high level of Gln contributes to the reduction in plant growth resulting from TOR inhibition. Glutamine synthetase activity was reduced by TOR inhibition while the enzyme amount increased. In conclusion, our findings show that the TOR pathway is intimately connected to N metabolism and that a decrease in TOR activity results in glutamine synthetase-dependent Gln and amino acid accumulation.
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Affiliation(s)
- Camille Ingargiola
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Isabelle Jéhanno
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Céline Forzani
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Anne Marmagne
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Justine Broutin
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Gilles Clément
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Anne-Sophie Leprince
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
- Faculté des Sciences et d'Ingénierie, Sorbonne Université, UFR 927, 4 Place Jussieu, 75252 Paris, France
| | - Christian Meyer
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
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28
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Cui Z, Joiner AMN, Jansen RM, Hurley JH. Amino acid sensing and lysosomal signaling complexes. Curr Opin Struct Biol 2023; 79:102544. [PMID: 36804703 DOI: 10.1016/j.sbi.2023.102544] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/05/2023] [Accepted: 01/11/2023] [Indexed: 02/18/2023]
Abstract
Amino acid pools in the cell are monitored by dedicated sensors, whose structures are now coming into view. The lysosomal Rag GTPases are central to this pathway, and the regulation of their GAP complexes, FLCN-FNIP and GATOR1, have been worked out in detail. For FLCN-FNIP, the entire chain of events from the arginine transporter SLC38A9 to substrate-specific mTORC1 activation has been visualized. The structure GATOR2 has been determined, hinting at an ordering of amino acid signaling across a larger size scale than anticipated. The centerpiece of lysosomal signaling, mTORC1, has been revealed to recognize its substrates by more nuanced and substrate-specific mechanisms than previous appreciated. Beyond the well-studied Rag GTPase and mTORC1 machinery, another lysosomal amino acid sensor/effector system, that of PQLC2 and the C9orf72-containing CSW complex, is coming into structural view. These developments hold promise for further insights into lysosomal physiology and lysosome-centric therapeutics.
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Affiliation(s)
- Zhicheng Cui
- 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
| | - Aaron M N Joiner
- 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
| | - 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, CA 94720, USA.
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29
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Liao CY, Pu Y, Nolan TM, Montes C, Guo H, Walley JW, Yin Y, Bassham DC. Brassinosteroids modulate autophagy through phosphorylation of RAPTOR1B by the GSK3-like kinase BIN2 in Arabidopsis. Autophagy 2023; 19:1293-1310. [PMID: 36151786 PMCID: PMC10012961 DOI: 10.1080/15548627.2022.2124501] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Macroautophagy/autophagy is a conserved recycling process that maintains cellular homeostasis during environmental stress. Autophagy is negatively regulated by TOR (target of rapamycin), a nutrient-regulated protein kinase that in plants is activated by several phytohormones, leading to increased growth. However, the detailed molecular mechanisms by which TOR integrates autophagy and hormone signaling are poorly understood. Here, we show that TOR modulates brassinosteroid (BR)-regulated plant growth and stress-response pathways. Active TOR was required for full BR-mediated growth in Arabidopsis thaliana. Autophagy was constitutively up-regulated upon blocking BR biosynthesis or signaling, and down-regulated by increasing the activity of the BR pathway. BIN2 (brassinosteroid-insensitive 2) kinase, a GSK3-like kinase functioning as a negative regulator in BR signaling, directly phosphorylated RAPTOR1B (regulatory-associated protein of TOR 1B), a substrate-recruiting subunit in the TOR complex, at a conserved serine residue within a typical BIN2 phosphorylation motif. Mutation of RAPTOR1B serine 916 to alanine, to block phosphorylation by BIN2, repressed autophagy and increased phosphorylation of the TOR substrate ATG13a (autophagy-related protein 13a). By contrast, this mutation had only a limited effect on growth. We present a model in which RAPTOR1B is phosphorylated and inhibited by BIN2 when BRs are absent, activating the autophagy pathway. When BRs signal and inhibit BIN2, RAPTOR1B is thus less inhibited by BIN2 phosphorylation. This leads to increased TOR activity and ATG13a phosphorylation, and decreased autophagy activity. Our studies define a new mechanism by which coordination between BR and TOR signaling pathways helps to maintain the balance between plant growth and stress responses.
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Affiliation(s)
- Ching-Yi Liao
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Yunting Pu
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Trevor M Nolan
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Christian Montes
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA
| | - Hongqing Guo
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Justin W Walley
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA
| | - Yanhai Yin
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
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30
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Riquelme I, Pérez-Moreno P, Mora-Lagos B, Ili C, Brebi P, Roa JC. Long Non-Coding RNAs (lncRNAs) as Regulators of the PI3K/AKT/mTOR Pathway in Gastric Carcinoma. Int J Mol Sci 2023; 24:ijms24076294. [PMID: 37047267 PMCID: PMC10094576 DOI: 10.3390/ijms24076294] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Gastric cancer (GC) represents ~10% of the global cancer-related deaths, increasingly affecting the younger population in active stages of life. The high mortality of GC is due to late diagnosis, the presence of metastasis and drug resistance development. Additionally, current clinical markers do not guide the patient management adequately, thereby new and more reliable biomarkers and therapeutic targets are still needed for this disease. RNA-seq technology has allowed the discovery of new types of RNA transcripts including long non-coding RNAs (lncRNAs), which are able to regulate the gene/protein expression of many signaling pathways (e.g., the PI3K/AKT/mTOR pathway) in cancer cells by diverse molecular mechanisms. In addition, these lncRNAs might also be proposed as promising diagnostic or prognostic biomarkers or as potential therapeutic targets in GC. This review describes important topics about some lncRNAs that have been described as regulators of the PI3K/AKT/mTOR signaling pathway, and hence, their potential oncogenic role in the development of this malignancy.
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Affiliation(s)
- Ismael Riquelme
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Temuco 4810101, Chile
- Correspondence: (I.R.); (J.C.R.); Tel.: +56-95923-6933 (I.R.); +56-22354-1061 (J.C.R.)
| | - Pablo Pérez-Moreno
- Millennium Institute on Immunology and Immunotherapy (MIII), Center for Cancer Prevention and Control (CECAN), Department of Pathology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8380000, Chile
| | - Bárbara Mora-Lagos
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Temuco 4810101, Chile
| | - Carmen Ili
- Millennium Institute on Immunology and Immunotherapy (MIII), Laboratory of Integrative Biology (LIBi), Center for Excellence in Translational Medicine—Scientific and Technological Bioresource Nucleus (CEMT-BIOREN), Universidad de La Frontera, Temuco 4810296, Chile
| | - Priscilla Brebi
- Millennium Institute on Immunology and Immunotherapy (MIII), Laboratory of Integrative Biology (LIBi), Center for Excellence in Translational Medicine—Scientific and Technological Bioresource Nucleus (CEMT-BIOREN), Universidad de La Frontera, Temuco 4810296, Chile
| | - Juan Carlos Roa
- Millennium Institute on Immunology and Immunotherapy (MIII), Center for Cancer Prevention and Control (CECAN), Department of Pathology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8380000, Chile
- Correspondence: (I.R.); (J.C.R.); Tel.: +56-95923-6933 (I.R.); +56-22354-1061 (J.C.R.)
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Ibrahim YH, Pantelios S, Mutvei AP. An affinity tool for the isolation of endogenous active mTORC1 from various cellular sources. J Biol Chem 2023; 299:104644. [PMID: 36965617 PMCID: PMC10164890 DOI: 10.1016/j.jbc.2023.104644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 03/02/2023] [Accepted: 03/13/2023] [Indexed: 03/27/2023] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is a central regulator of mammalian cell growth that is dysregulated in a number of human diseases, including metabolic syndromes, aging and cancer. Structural, biochemical and pharmacological studies that have increased our understanding of how mTORC1 executes growth control often relied upon purified mTORC1 protein. However, current immunoaffinity-based purification methods are expensive, inefficient, and do not necessarily isolate endogenous mTORC1, hampering their overall utility in research. Here we present a simple tool to isolate endogenous mTORC1 from various cellular sources. By recombinantly expressing and isolating mTORC1-binding Rag GTPases from E. Coli and using them as affinity probes, we demonstrate that mTORC1 can be isolated from mouse, bovine and human sources. Our results indicate that mTORC1 isolated by this relatively inexpensive method is catalytically active and amenable to scaling. Collectively, this tool may be utilized to isolate mTORC1 from various cellular sources, organs, and disease contexts, aiding mTORC1-related research.
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Affiliation(s)
| | - Spyridon Pantelios
- Department of Immunology, Pathology and Genetics, Uppsala University, Uppsala, Sweden
| | - Anders P Mutvei
- Department of Immunology, Pathology and Genetics, Uppsala University, Uppsala, Sweden.
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32
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Frias MA, Hatipoglu A, Foster DA. Regulation of mTOR by phosphatidic acid. Trends Endocrinol Metab 2023; 34:170-180. [PMID: 36732094 PMCID: PMC9957947 DOI: 10.1016/j.tem.2023.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 01/03/2023] [Indexed: 02/03/2023]
Abstract
mTORC1, the mammalian target of rapamycin complex 1, is a key regulator of cellular physiology. The lipid metabolite phosphatidic acid (PA) binds to and activates mTORC1 in response to nutrients and growth factors. We review structural findings and propose a model for PA activation of mTORC1. PA binds to a highly conserved sequence in the α4 helix of the FK506 binding protein 12 (FKBP12)/rapamycin-binding (FRB) domain of mTOR. It is proposed that PA binding to two adjacent positively charged amino acids breaks and shortens the C-terminal region of helix α4. This has profound consequences for both substrate binding and the catalytic activity of mTORC1.
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Affiliation(s)
- Maria A Frias
- Department of Biology and Health Promotion, St. Francis College, Brooklyn, NY 11201, USA; Department of Biological Sciences, Hunter College of the City University of New York, New York, NY 10065, USA.
| | - Ahmet Hatipoglu
- Department of Biological Sciences, Hunter College of the City University of New York, New York, NY 10065, USA; Biochemistry Program, Graduate Center of the City University of New York, New York, NY 10016, USA
| | - David A Foster
- Department of Biological Sciences, Hunter College of the City University of New York, New York, NY 10065, USA; Biochemistry Program, Graduate Center of the City University of New York, New York, NY 10016, USA; Biology Program, Graduate Center of the City University of New York, New York, NY 10016, USA; Department of Pharmacology, Weill Cornell Medicine, New York, NY 10021, USA.
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33
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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: 0] [Impact Index Per Article: 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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34
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Stary D, Nepovimova E, Kuca K, Bajda M. Searching for new mTOR kinase inhibitors: Analysis of binding sites and validation of docking protocols. Chem Biol Drug Des 2023; 101:103-119. [PMID: 35945665 DOI: 10.1111/cbdd.14126] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/18/2022] [Accepted: 07/30/2022] [Indexed: 12/15/2022]
Abstract
The mammalian target of rapamycin (mTOR) is an important biological target for development of novel anticancer drugs and potential antiageing agents. Therefore, many scientific groups search for mTOR kinase inhibitors. Herein, we present structure-based approach which could be helpful in the studies on new bioactive compounds. Method validation was preceded by structural analysis of ATP catalytic cleft and FRB domain. In silico studies allowed us to point crucial amino acid residues for ligand binding and develop optimal docking protocols. The presented methodology could be applied for design and development of potential mTOR kinase inhibitors.
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Affiliation(s)
- Dorota Stary
- Department of Physicochemical Drug Analysis, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland.,Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic.,Doctoral School of Medical and Health Sciences, Jagiellonian University Medical College, Cracow, Poland
| | - Eugenie Nepovimova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Kamil Kuca
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Marek Bajda
- Department of Physicochemical Drug Analysis, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland.,Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
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35
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Jamsheer K M, Awasthi P, Laxmi A. The social network of target of rapamycin complex 1 in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:7026-7040. [PMID: 35781571 DOI: 10.1093/jxb/erac278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Target of rapamycin complex 1 (TORC1) is a highly conserved serine-threonine protein kinase crucial for coordinating growth according to nutrient availability in eukaryotes. It works as a central integrator of multiple nutrient inputs such as sugar, nitrogen, and phosphate and promotes growth and biomass accumulation in response to nutrient sufficiency. Studies, especially in the past decade, have identified the central role of TORC1 in regulating growth through interaction with hormones, photoreceptors, and stress signaling machinery in plants. In this review, we comprehensively analyse the interactome and phosphoproteome of the Arabidopsis TORC1 signaling network. Our analysis highlights the role of TORC1 as a central hub kinase communicating with the transcriptional and translational apparatus, ribosomes, chaperones, protein kinases, metabolic enzymes, and autophagy and stress response machinery to orchestrate growth in response to nutrient signals. This analysis also suggests that along with the conserved downstream components shared with other eukaryotic lineages, plant TORC1 signaling underwent several evolutionary innovations and co-opted many lineage-specific components during. Based on the protein-protein interaction and phosphoproteome data, we also discuss several uncharacterized and unexplored components of the TORC1 signaling network, highlighting potential links for future studies.
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Affiliation(s)
- Muhammed Jamsheer K
- Amity Institute of Genome Engineering, Amity University Uttar Pradesh, Noida 201313, India
| | - Prakhar Awasthi
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Ashverya Laxmi
- National Institute of Plant Genome Research, New Delhi 110067, India
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36
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Mallén-Ponce MJ, Pérez-Pérez ME, Crespo JL. Deciphering the function and evolution of the target of rapamycin signaling pathway in microalgae. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6993-7005. [PMID: 35710309 PMCID: PMC9664231 DOI: 10.1093/jxb/erac264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Microalgae constitute a highly diverse group of photosynthetic microorganisms that are widely distributed on Earth. The rich diversity of microalgae arose from endosymbiotic events that took place early in the evolution of eukaryotes and gave rise to multiple lineages including green algae, the ancestors of land plants. In addition to their fundamental role as the primary source of marine and freshwater food chains, microalgae are essential producers of oxygen on the planet and a major biotechnological target for sustainable biofuel production and CO2 mitigation. Microalgae integrate light and nutrient signals to regulate cell growth. Recent studies identified the target of rapamycin (TOR) kinase as a central regulator of cell growth and a nutrient sensor in microalgae. TOR promotes protein synthesis and regulates processes that are induced under nutrient stress such as autophagy and the accumulation of triacylglycerol and starch. A detailed analysis of representative genomes from the entire microalgal lineage revealed that the highly conserved central components of the TOR pathway are likely to have been present in the last eukaryotic common ancestor, and the loss of specific TOR signaling elements at an early stage in the evolution of microalgae. Here we examine the evolutionary conservation of TOR signaling components in diverse microalgae and discuss recent progress of this signaling pathway in these organisms.
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Affiliation(s)
- Manuel J Mallén-Ponce
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Sevilla, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Sevilla, Spain
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37
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Mammalian Target of Rapamycin (mTOR) Signaling at the Crossroad of Muscle Fiber Fate in Sarcopenia. Int J Mol Sci 2022; 23:ijms232213823. [PMID: 36430301 PMCID: PMC9696247 DOI: 10.3390/ijms232213823] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/02/2022] [Accepted: 11/08/2022] [Indexed: 11/12/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) is a major regulator of skeletal myocyte viability. The signaling pathways triggered by mTOR vary according to the type of endogenous and exogenous factors (e.g., redox balance, nutrient availability, physical activity) as well as organismal age. Here, we provide an overview of mTOR signaling in skeletal muscle, with a special focus on the role played by mTOR in the development of sarcopenia. Intervention strategies targeting mTOR in sarcopenia (e.g., supplementation of plant extracts, hormones, inorganic ions, calorie restriction, and exercise) have also been discussed.
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38
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Hypomethylation of RPTOR in peripheral blood is associated with very early-stage lung cancer. Clin Chim Acta 2022; 537:173-180. [DOI: 10.1016/j.cca.2022.10.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/07/2022] [Accepted: 10/17/2022] [Indexed: 11/05/2022]
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39
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Ali ES, Mitra K, Akter S, Ramproshad S, Mondal B, Khan IN, Islam MT, Sharifi-Rad J, Calina D, Cho WC. Recent advances and limitations of mTOR inhibitors in the treatment of cancer. Cancer Cell Int 2022; 22:284. [PMID: 36109789 PMCID: PMC9476305 DOI: 10.1186/s12935-022-02706-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
The PI3K-Akt-mechanistic (formerly mammalian) target of the rapamycin (mTOR) signaling pathway is important in a variety of biological activities, including cellular proliferation, survival, metabolism, autophagy, and immunity. Abnormal PI3K-Akt-mTOR signalling activation can promote transformation by creating a cellular environment conducive to it. Deregulation of such a system in terms of genetic mutations and amplification has been related to several human cancers. Consequently, mTOR has been recognized as a key target for the treatment of cancer, especially for treating cancers with elevated mTOR signaling due to genetic or metabolic disorders. In vitro and in vivo, rapamycin which is an immunosuppressant agent actively suppresses the activity of mTOR and reduces cancer cell growth. As a result, various sirolimus-derived compounds have now been established as therapies for cancer, and now these medications are being investigated in clinical studies. In this updated review, we discuss the usage of sirolimus-derived compounds and other drugs in several preclinical or clinical studies as well as explain some of the challenges involved in targeting mTOR for treating various human cancers.
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40
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mTOR Complex 1 Content and Regulation Is Adapted to Animal Longevity. Int J Mol Sci 2022; 23:ijms23158747. [PMID: 35955882 PMCID: PMC9369240 DOI: 10.3390/ijms23158747] [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: 06/29/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 11/16/2022] Open
Abstract
Decreased content and activity of the mechanistic target of rapamycin (mTOR) signalling pathway, as well as the mTOR complex 1 (mTORC1) itself, are key traits for animal species and human longevity. Since mTORC1 acts as a master regulator of intracellular metabolism, it is responsible, at least in part, for the longevous phenotype. Conversely, increased content and activity of mTOR signalling and mTORC1 are hallmarks of ageing. Additionally, constitutive and aberrant activity of mTORC1 is also found in age-related diseases such as Alzheimer’s disease (AD) and cancer. The downstream processes regulated through this network are diverse, and depend upon nutrient availability. Hence, multiple nutritional strategies capable of regulating mTORC1 activity and, consequently, delaying the ageing process and the development of age-related diseases, are under continuous study. Among these, the restriction of calories is still the most studied and robust intervention capable of downregulating mTOR signalling and feasible for application in the human population.
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41
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Yu Z, Chen J, Takagi E, Wang F, Saha B, Liu X, Joubert LM, Gleason CE, Jin M, Li C, Nowotny C, Agard D, Cheng Y, Pearce D. Interactions between mTORC2 core subunits Rictor and mSin1 dictate selective and context-dependent phosphorylation of substrate kinases SGK1 and Akt. J Biol Chem 2022; 298:102288. [PMID: 35926713 PMCID: PMC9440446 DOI: 10.1016/j.jbc.2022.102288] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 12/02/2022] Open
Abstract
Mechanistic target of rapamycin complex 2 (mTORC2) is a multi-subunit kinase complex, central to multiple essential signaling pathways. Two core subunits, Rictor and mSin1, distinguish it from the related mTORC1 and support context-dependent phosphorylation of its substrates. mTORC2 structures have been determined previously; however, important questions remain, particularly regarding the structural determinants mediating substrate specificity and context-dependent activity. Here, we used cryo-EM to obtain high-resolution structures of the human mTORC2 apo-complex in the presence of substrates Akt and SGK1. Using functional assays, we then tested predictions suggested by substrate-induced structural changes in mTORC2. For the first time, we visualized in the apo-state the side chain interactions between Rictor and mTOR that sterically occlude recruitment of mTORC1 substrates and confer resistance to the mTORC1 inhibitor rapamycin. Also in the apo-state, we observed that mSin1 formed extensive contacts with Rictor via a pair of short α-helices nestled between two Rictor helical repeat clusters, as well as by an extended strand that makes multiple weak contacts with Rictor helical cluster 1. In co-complex structures, we found that SGK1, but not Akt, markedly altered the conformation of the mSin1 N-terminal extended strand, disrupting multiple weak interactions while inducing a large rotation of mSin1 residue Arg-83, which then interacts with a patch of negatively charged residues within Rictor. Finally, we demonstrate mutation of Arg-83 to Ala selectively disrupts mTORC2-dependent phosphorylation of SGK1, but not of Akt, supporting context-dependent substrate selection. These findings provide new structural and functional insights into mTORC2 specificity and context-dependent activity.
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Affiliation(s)
- Zanlin Yu
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Junliang Chen
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Enzo Takagi
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Feng Wang
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Bidisha Saha
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Xi Liu
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Lydia-Marie Joubert
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California, USA
| | - Catherine E Gleason
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Mingliang Jin
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Chengmin Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Carlos Nowotny
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - David Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA; Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA
| | - David Pearce
- Department of Medicine, Division of Nephrology, and Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA.
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Stress- and metabolic responses of Candida albicans require Tor1 kinase N-terminal HEAT repeats. PLoS Pathog 2022; 18:e1010089. [PMID: 35687592 PMCID: PMC9223334 DOI: 10.1371/journal.ppat.1010089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 06/23/2022] [Accepted: 05/12/2022] [Indexed: 11/19/2022] Open
Abstract
Whether to commit limited cellular resources toward growth and proliferation, or toward survival and stress responses, is an essential determination made by Target of Rapamycin Complex 1 (TORC1) for a eukaryotic cell in response to favorable or adverse conditions. Loss of TORC1 function is lethal. The TORC1 inhibitor rapamycin that targets the highly conserved Tor kinase domain kills fungal pathogens like Candida albicans, but is also severely toxic to human cells. The least conserved region of fungal and human Tor kinases are the N-terminal HEAT domains. We examined the role of the 8 most N-terminal HEAT repeats of C. albicans Tor1. We compared nutritional- and stress responses of cells that express a message for N-terminally truncated Tor1 from repressible tetO, with cells expressing wild type TOR1 from tetO or from the native promoter. Some but not all stress responses were significantly impaired by loss of Tor1 N-terminal HEAT repeats, including those to oxidative-, cell wall-, and heat stress; in contrast, plasma membrane stress and antifungal agents that disrupt plasma membrane function were tolerated by cells lacking this Tor1 region. Translation was inappropriately upregulated during oxidative stress in cells lacking N-terminal Tor1 HEAT repeats despite simultaneously elevated Gcn2 activity, while activation of the oxidative stress response MAP kinase Hog1 was weak. Conversely, these cells were unable to take advantage of favorable nutritional conditions by accelerating their growth. Consuming oxygen more slowly than cells containing wild type TOR1 alleles during growth in glucose, cells lacking N-terminal Tor1 HEAT repeats additionally were incapable of utilizing non-fermentable carbon sources. They were also hypersensitive to inhibitors of specific complexes within the respiratory electron transport chain, suggesting that inefficient ATP generation and a resulting dearth of nucleotide sugar building blocks for cell wall polysaccharides causes cell wall integrity defects in these mutants. Genome-wide expression analysis of cells lacking N-terminal HEAT repeats showed dysregulation of carbon metabolism, cell wall biosynthetic enzymes, translational machinery biosynthesis, oxidative stress responses, and hyphal- as well as white-opaque cell type-associated genes. Targeting fungal-specific Tor1 N-terminal HEAT repeats with small molecules might selectively abrogate fungal viability, especially when during infection multiple stresses are imposed by the host immune system. Whether growing harmlessly on our mucous membranes in competition with bacterial multitudes, or invading our tissues and bloodstream, the fungus Candida albicans must be capable of rapid growth when it finds abundant nutrients and favorable conditions. It must also be able to switch to stress- and survival mode when encountering host immune cells and when starving for nutrients. Tor1 kinase is the central regulator at the heart of these cellular decisions. As an essential protein, it is an attractive drug target. But the Tor1 kinase domain is very similar to its human counterpart, rendering its inhibitors like rapamycin toxic for humans. We identified a region of helical protein-protein interaction domains, the N-terminal HEAT repeats, as the least conserved part of C. albicans Tor1. Using genetic- and genome-wide expression analysis, we found that 8 N-terminal HEAT repeats are required for growth acceleration in nutrient-rich environments and for decreased translation in starvation- and stress conditions. This Tor1 region contributes to oxidative-, cell wall- and heat stress reponses, to hyphal growth and to respiration, but apparently not to plasma membrane stress endurance or fermentation. Small molecules that disrupt the protein-protein interactions mediated by this region could become fungal-selective inhibitors of Tor kinase.
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Yang M, Lu Y, Piao W, Jin H. The Translational Regulation in mTOR Pathway. Biomolecules 2022; 12:biom12060802. [PMID: 35740927 PMCID: PMC9221026 DOI: 10.3390/biom12060802] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 12/12/2022] Open
Abstract
The mechanistic/mammalian target of rapamycin (mTOR) plays a master role in cell proliferation and growth in response to insulin, amino acids, energy levels, and oxygen. mTOR can coordinate upstream signals with downstream effectors, including transcriptional and translational apparatuses to regulate fundamental cellular processes such as energy utilization, protein synthesis, autophagy, cell growth, and proliferation. Of the above, protein synthesis is highly energy-consuming; thus, mRNA translation is under the tight and immediate control of mTOR signaling. The translational regulation driven by mTOR signaling mainly relies on eukaryotic translation initiation factor 4E (eIF4E)-binding protein (4E-BP), ribosomal protein S6 kinase (S6K), and its downstream players, which are significant in rapid cellular response to environmental change. mTOR signaling not only controls the general mRNA translation, but preferential mRNA translation as well. This means that mTOR signaling shows the stronger selectivity to particular target mRNAs. Some evidence has supported the contribution of 4E-BP and La-related proteins 1 (LARP1) to such translational regulation. In this review, we summarize the mTOR pathway and mainly focus on mTOR-mediated mRNA translational regulation. We introduce the major components of mTOR signaling and their functions in translational control in a general or particular manner, and describe how the specificity of regulation is coordinated. Furthermore, we summarize recent research progress and propose additional ideas for reference. Because the mTOR pathway is on the center of cell growth and metabolism, comprehensively understanding this pathway will contribute to the therapy of related diseases, including cancers, type 2 diabetes, obesity, and neurodegeneration.
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Affiliation(s)
| | | | | | - Hua Jin
- Correspondence: (W.P.); (H.J.)
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44
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mTOR substrate phosphorylation in growth control. Cell 2022; 185:1814-1836. [PMID: 35580586 DOI: 10.1016/j.cell.2022.04.013] [Citation(s) in RCA: 118] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 12/20/2022]
Abstract
The target of rapamycin (TOR), discovered 30 years ago, is a highly conserved serine/threonine protein kinase that plays a central role in regulating cell growth and metabolism. It is activated by nutrients, growth factors, and cellular energy. TOR forms two structurally and functionally distinct complexes, TORC1 and TORC2. TOR signaling activates cell growth, defined as an increase in biomass, by stimulating anabolic metabolism while inhibiting catabolic processes. With emphasis on mammalian TOR (mTOR), we comprehensively reviewed the literature and identified all reported direct substrates. In the context of recent structural information, we discuss how mTORC1 and mTORC2, despite having a common catalytic subunit, phosphorylate distinct substrates. We conclude that the two complexes recruit different substrates to phosphorylate a common, minimal motif.
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45
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Friedrich D, Marintchev A, Arthanari H. The metaphorical swiss army knife: The multitude and diverse roles of HEAT domains in eukaryotic translation initiation. Nucleic Acids Res 2022; 50:5424-5442. [PMID: 35552740 PMCID: PMC9177959 DOI: 10.1093/nar/gkac342] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 11/24/2022] Open
Abstract
Biomolecular associations forged by specific interaction among structural scaffolds are fundamental to the control and regulation of cell processes. One such structural architecture, characterized by HEAT repeats, is involved in a multitude of cellular processes, including intracellular transport, signaling, and protein synthesis. Here, we review the multitude and versatility of HEAT domains in the regulation of mRNA translation initiation. Structural and cellular biology approaches, as well as several biophysical studies, have revealed that a number of HEAT domain-mediated interactions with a host of protein factors and RNAs coordinate translation initiation. We describe the basic structural architecture of HEAT domains and briefly introduce examples of the cellular processes they dictate, including nuclear transport by importin and RNA degradation. We then focus on proteins in the translation initiation system featuring HEAT domains, specifically the HEAT domains of eIF4G, DAP5, eIF5, and eIF2Bϵ. Comparative analysis of their remarkably versatile interactions, including protein–protein and protein–RNA recognition, reveal the functional importance of flexible regions within these HEAT domains. Here we outline how HEAT domains orchestrate fundamental aspects of translation initiation and highlight open mechanistic questions in the area.
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Affiliation(s)
- Daniel Friedrich
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Assen Marintchev
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
| | - Haribabu Arthanari
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
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46
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Exploratory Analysis of Selected Components of the mTOR Pathway Reveals Potentially Crucial Associations with Childhood Malnutrition. Nutrients 2022; 14:nu14081612. [PMID: 35458174 PMCID: PMC9031007 DOI: 10.3390/nu14081612] [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] [Received: 02/22/2022] [Revised: 03/13/2022] [Accepted: 03/25/2022] [Indexed: 12/10/2022] Open
Abstract
Dysregulations in the mammalian target of rapamycin (mTOR) pathway are associated with several human anomalies. We aimed to elucidate possible implications for potential aberrations in the mTOR pathway with childhood malnutrition. We analyzed the activity of phospho-mTORC1 and the expressions of several mTOR pathway genes, namely: MTOR, TSC1, LAMTOR2, RPS6K1 and RICTOR from peripheral blood mononuclear cells isolated from venous blood of children suffering from different forms of malnutrition and compared them with those from healthy children. Significant reduction in the phosphorylation of mTORC1 was noted, as well as a decrease in expression of LAMTOR2 gene and increase in TSC1 gene expression were observed between malnourished children in comparison to the healthy children. The deregulation in the activity of the TSC1 and LAMTOR2 gene was significantly associated with all forms of childhood malnutrition. Our findings provide key insights into possible down-modulation in the overall activity of the mTOR pathway in childhood malnutrition. Further studies focusing on the analysis of a multitude of components involved in the mTOR pathway both at the gene and protein expression levels are required for conclusive evidence for the aforementioned proposition.
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47
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Tsverov J, Yegorov K, Powers T. Identification of defined structural elements within TOR2 kinase required for TOR Complex 2 assembly and function in S. cerevisiae. Mol Biol Cell 2022; 33:ar44. [PMID: 35293776 PMCID: PMC9282017 DOI: 10.1091/mbc.e21-12-0611] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
mTOR is a large protein kinase that assembles into two multi-subunit protein complexes, mTORC1 and mTORC2, to regulate cell growth in eukaryotic cells. While significant progress has been made in our understanding of the composition and structure of these complexes, important questions remain regarding the role of specific sequences within mTOR important for complex formation and activity. To address these issues, we have used a molecular genetic approach to explore TOR Complex assembly in budding yeast, where two closely related TOR paralogs, TOR1 and TOR2, partition preferentially into TORC1 versus TORC2, respectively. We previously identified a ∼500 amino acid segment within the N-terminal half of each protein, termed the Major Assembly Specificity (MAS) Domain, which can govern specificity in formation of each complex. In this study, we have extended the use of chimeric TOR1-TOR2 genes as a "sensitized" genetic system to identify specific subdomains rendered essential for TORC2 function, using synthetic lethal interaction analyses. Our findings reveal important design principles underlying the dimeric assembly of TORC2, as well as identify specific segments within the MAS domain critical for TORC2 function, to a level approaching single amino acid resolution. Together these findings highlight the complex and cooperative nature of TOR Complex assembly and function.
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Affiliation(s)
- Jennifer Tsverov
- Department of Molecular and Cellular Biology, College of Biological Sciences, UC Davis
| | - Kristina Yegorov
- Department of Molecular and Cellular Biology, College of Biological Sciences, UC Davis
| | - Ted Powers
- Department of Molecular and Cellular Biology, College of Biological Sciences, UC Davis
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48
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Yang Z, Huang C, Wen X, Liu W, Huang X, Li Y, Zang J, Weng Z, Lu D, Tsang CK, Li K, Xu A. Circular RNA circ-FoxO3 attenuates blood-brain barrier damage by inducing autophagy during ischemia/reperfusion. Mol Ther 2022; 30:1275-1287. [PMID: 34763084 PMCID: PMC8899525 DOI: 10.1016/j.ymthe.2021.11.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 09/23/2021] [Accepted: 11/03/2021] [Indexed: 02/08/2023] Open
Abstract
Blood-brain barrier (BBB) damage can be a result of central nervous system (CNS) diseases and may be a cause of CNS deterioration. However, there are still many unknowns regarding effective and targeted therapies for maintaining BBB integrity during ischemia/reperfusion (I/R) injury. In this study, we demonstrate that the circular RNA of FoxO3 (circ-FoxO3) promotes autophagy via mTORC1 inhibition to attenuate BBB collapse under I/R. Upregulation of circ-FoxO3 and autophagic flux were detected in brain microvessel endothelial cells in patients with hemorrhagic transformation and in mice models with middle cerebral artery occlusion/reperfusion. In vivo and in vitro studies indicated that circ-FoxO3 alleviated BBB damage principally by autophagy activation. Mechanistically, we found that circ-FoxO3 inhibited mTORC1 activity mainly by sequestering mTOR and E2F1, thus promoting autophagy to clear cytotoxic aggregates for improving BBB integrity. These results demonstrate that circ-FoxO3 plays a novel role in protecting against BBB damage, and that circ-FoxO3 may be a promising therapeutic target for neurological disorders associated with BBB damage.
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Affiliation(s)
- Zhenguo Yang
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China,Affiliated Hospital of Guangdong Medical University, 57 South Renmin Ave, Zhanjiang 524001, China
| | - Cheng Huang
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Xueyi Wen
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Wenlin Liu
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China,Affiliated Hospital of Guangdong Medical University, 57 South Renmin Ave, Zhanjiang 524001, China
| | - Xiaoxiong Huang
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Yufeng Li
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Jiankun Zang
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Zean Weng
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Dan Lu
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Chi Kwan Tsang
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China
| | - Keshen Li
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China.
| | - Anding Xu
- Department of Neurology and Stroke Center, The First Affiliated Hospital, & Clinical Neuroscience Institute of Jinan University, 613 West Huangpu Ave, Guangzhou 510632, China.
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49
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Srinivasan AR, Tran TT, Bonini NM. Loss of miR-34 in Drosophila dysregulates protein translation and protein turnover in the aging brain. Aging Cell 2022; 21:e13559. [PMID: 35166006 PMCID: PMC8920459 DOI: 10.1111/acel.13559] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 12/20/2021] [Accepted: 01/11/2022] [Indexed: 12/27/2022] Open
Abstract
Aging is a risk factor for neurodegenerative disease, but precise mechanisms that influence this relationship are still under investigation. Work in Drosophila melanogaster identified the microRNA miR‐34 as a modifier of aging and neurodegeneration in the brain. MiR‐34 mutants present aspects of early aging, including reduced lifespan, neurodegeneration, and a buildup of the repressive histone mark H3K27me3. To better understand how miR‐34 regulated pathways contribute to age‐associated phenotypes in the brain, here we transcriptionally profiled the miR‐34 mutant brain. This identified that genes associated with translation are dysregulated in the miR‐34 mutant. The brains of these animals show increased translation activity, accumulation of protein aggregation markers, and altered autophagy activity. To determine if altered H3K27me3 was responsible for this proteostasis dysregulation, we studied the effects of increased H3K27me3 by mutating the histone demethylase Utx. Reduced Utx activity enhanced neurodegeneration and mimicked the protein accumulation seen in miR‐34 mutant brains. However, unlike the miR‐34 mutant, Utx mutant brains did not show similar altered autophagy or translation activity, suggesting that additional miR‐34‐targeted pathways are involved. Transcriptional analysis of predicted miR‐34 targets identified Lst8, a subunit of Tor Complex 1 (TORC1), as a potential target. We confirmed that miR‐34 regulates the 3’ UTR of Lst8 and identified several additional predicted miR‐34 targets that may be critical for maintaining proteostasis and brain health. Together, these results present novel understanding of the brain and the role of the conserved miRNA miR‐34 in impacting proteostasis in the brain with age.
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Affiliation(s)
| | - Tracy T. Tran
- Department of Biology University of Pennsylvania Philadelphia Pennsylvania USA
| | - Nancy M. Bonini
- Department of Biology University of Pennsylvania Philadelphia Pennsylvania USA
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Structural mechanism of allosteric activation of TRPML1 by PI(3,5)P 2 and rapamycin. Proc Natl Acad Sci U S A 2022; 119:2120404119. [PMID: 35131932 PMCID: PMC8851561 DOI: 10.1073/pnas.2120404119] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2022] [Indexed: 12/22/2022] Open
Abstract
Rapamycin is a specific inhibitor of mammalian target of rapamycin (mTOR). Rapamycin can also activate transient receptor potential mucolipin 1 (TRPML1), a phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]–gated lysosomal cation channel whose loss-of-function mutations directly cause mucolipidosis type IV disease. We determined the high-resolution cryoelectron microscopy structures of TRPML1 in various ligand-bound states, including the open TRPML1 in complex with PI(3,5)P2 and a rapamycin analog at 2.1 Å. These structures reveal how rapamycin and PI(3,5)P2 bind at two distinct sites and allosterically activate the channel. Considering the high potency of TRPML1 activation by rapamycin and PI(3,5)P2, it is conceivable that some pharmacological effects from the therapeutic use of rapamycin may come from the TRPML1-dependent mechanism rather than mTOR inhibition. Transient receptor potential mucolipin 1 (TRPML1) is a Ca2+-permeable, nonselective cation channel ubiquitously expressed in the endolysosomes of mammalian cells and its loss-of-function mutations are the direct cause of type IV mucolipidosis (MLIV), an autosomal recessive lysosomal storage disease. TRPML1 is a ligand-gated channel that can be activated by phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] as well as some synthetic small-molecule agonists. Recently, rapamycin has also been shown to directly bind and activate TRPML1. Interestingly, both PI(3,5)P2 and rapamycin have low efficacy in channel activation individually but together they work cooperatively and activate the channel with high potency. To reveal the structural basis underlying the synergistic activation of TRPML1 by PI(3,5)P2 and rapamycin, we determined the high-resolution cryoelectron microscopy (cryo-EM) structures of the mouse TRPML1 channel in various states, including apo closed, PI(3,5)P2-bound closed, and PI(3,5)P2/temsirolimus (a rapamycin analog)-bound open states. These structures, combined with electrophysiology, elucidate the molecular details of ligand binding and provide structural insight into how the TRPML1 channel integrates two distantly bound ligand stimuli and facilitates channel opening.
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