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Li W, Li Y, Wang M, Liu H, Hong G, Jiang L, Liu Z, Wu Y, Yuan L, Zhao X, He Z, Guo S, Xiao Y, Bi X, Xia M, Zou G, Zhang L, Gao J, Fu X. TNFAIP8L2 maintains hair cell function and regulates age-related hearing loss via mTORC1 signaling. Mol Ther 2025:S1525-0016(25)00218-7. [PMID: 40165373 DOI: 10.1016/j.ymthe.2025.03.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2024] [Revised: 02/15/2025] [Accepted: 03/25/2025] [Indexed: 04/02/2025] Open
Abstract
Age-related hearing loss (ARHL) is one of the most prevalent and complex disorders. Our previous study demonstrated that abnormal activation of mammalian target of rapamycin complex 1 (mTORC1) signaling in the cochlear neurosensory epithelium causes auditory hair cell (HC) damage and contributes to ARHL. However, the underlying mechanism of mTORC1 activation remains unclear. In this study, we identified tumor necrosis factor-alpha-induced protein 8-like 2 (TNFAIP8L2), an immune regulatory gene, as a potential candidate. To elucidate the effect of TNFAIP8L2 on mTORC1 signaling in the neurosensory epithelium and on hearing function, we generated a Tnfaip8l2-deficient (Tnfaip8l2-/-) mouse model. We discovered that Tnfaip8l2 deficiency led to features of oxidative stress in cochlear HCs and age-related hearing degeneration, exhibiting a similar phenotype to the mTORC1-over-activated Tsc1-cKO mice described previously. Furthermore, rapamycin, a well-known mTORC1 inhibitor, significantly mitigated the hearing dysfunction caused by Tnfaip8l2-deficiency. Mechanistically, we found that TNFAIP8L2 regulates mTORC1 signaling by simultaneously inhibiting the GTPase activity of Ras homolog enriched in brain (RHEB) and Ras-related C3 botulinum toxin substrate 1 (RAC1). Notably, both RHEB and RAC1 inhibitors alleviated the hearing phenotype observed in Tnfaip8l2-/- mice by inhibiting mTORC1 signaling. Collectively, our results provide insights into the activation of the mTORC1 pathway in aged mouse cochleae and positions TNFAIP8L2 as a valuable theoretical strategy.
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Affiliation(s)
- Wen Li
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Yu Li
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Min Wang
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Hao Liu
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Guodong Hong
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Luhan Jiang
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Ziyi Liu
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Yunhao Wu
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Liangjie Yuan
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Xiaoxu Zhao
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Zuhong He
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Siwei Guo
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Yu Xiao
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Xiuli Bi
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Ming Xia
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Guichang Zou
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China
| | - Lining Zhang
- School of Basic Medical Sciences, Shandong University, Jinan, Shandong 250100, China
| | - Jiangang Gao
- School of Life Science, Shandong University, Qingdao, Shandong 266237, China
| | - Xiaolong Fu
- School of Clinical and Basic Medical Sciences, Shandong Provincial Hospital, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250117, China; Department of Neurology, Aerospace Center Hospital, School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
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Bérard M, Merlini L, Martin SG. Proteomic and phosphoproteomic analyses reveal that TORC1 is reactivated by pheromone signaling during sexual reproduction in fission yeast. PLoS Biol 2024; 22:e3002963. [PMID: 39705284 PMCID: PMC11750111 DOI: 10.1371/journal.pbio.3002963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2024] [Revised: 01/21/2025] [Accepted: 12/02/2024] [Indexed: 12/22/2024] Open
Abstract
Starvation, which is associated with inactivation of the growth-promoting TOR complex 1 (TORC1), is a strong environmental signal for cell differentiation. In the fission yeast Schizosaccharomyces pombe, nitrogen starvation has distinct physiological consequences depending on the presence of mating partners. In their absence, cells enter quiescence, and TORC1 inactivation prolongs their life. In presence of compatible mates, TORC1 inactivation is essential for sexual differentiation. Gametes engage in paracrine pheromone signaling, grow towards each other, fuse to form the diploid zygote, and form resistant, haploid spore progenies. To understand the signaling changes in the proteome and phospho-proteome during sexual reproduction, we developed cell synchronization strategies and present (phospho-)proteomic data sets that dissect pheromone from starvation signals over the sexual differentiation and cell-cell fusion processes. Unexpectedly, these data sets reveal phosphorylation of ribosomal protein S6 during sexual development, which we establish requires TORC1 activity. We demonstrate that TORC1 is re-activated by pheromone signaling, in a manner that does not require autophagy. Mutants with low TORC1 re-activation exhibit compromised mating and poorly viable spores. Thus, while inactivated to initiate the mating process, TORC1 is reactivated by pheromone signaling in starved cells to support sexual reproduction.
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Affiliation(s)
- Melvin Bérard
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Laura Merlini
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
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3
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Zwakenberg S, Westland D, van Es RM, Rehmann H, Anink J, Ciapaite J, Bosma M, Stelloo E, Liv N, Sobrevals Alcaraz P, Verhoeven-Duif NM, Jans JJM, Vos HR, Aronica E, Zwartkruis FJT. mTORC1 restricts TFE3 activity by auto-regulating its presence on lysosomes. Mol Cell 2024; 84:4368-4384.e6. [PMID: 39486419 DOI: 10.1016/j.molcel.2024.10.009] [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: 10/19/2023] [Revised: 07/10/2024] [Accepted: 10/07/2024] [Indexed: 11/04/2024]
Abstract
To stimulate cell growth, the protein kinase complex mTORC1 requires intracellular amino acids for activation. Amino-acid sufficiency is relayed to mTORC1 by Rag GTPases on lysosomes, where growth factor signaling enhances mTORC1 activity via the GTPase Rheb. In the absence of amino acids, GATOR1 inactivates the Rags, resulting in lysosomal detachment and inactivation of mTORC1. We demonstrate that in human cells, the release of mTORC1 from lysosomes depends on its kinase activity. In accordance with a negative feedback mechanism, activated mTOR mutants display low lysosome occupancy, causing hypo-phosphorylation and nuclear localization of the lysosomal substrate TFE3. Surprisingly, mTORC1 activated by Rheb does not increase the cytoplasmic/lysosomal ratio of mTORC1, indicating the existence of mTORC1 pools with distinct substrate specificity. Dysregulation of either pool results in aberrant TFE3 activity and may explain nuclear accumulation of TFE3 in epileptogenic malformations in focal cortical dysplasia type II (FCD II) and tuberous sclerosis (TSC).
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Affiliation(s)
- Susan Zwakenberg
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands; Oncode Institute, Utrecht, the Netherlands
| | - Denise Westland
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Robert M van Es
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands; Oncode Institute, Utrecht, the Netherlands
| | - Holger Rehmann
- Department of Energy and Life Science, Flensburg University of Applied Sciences, Flensburg, Germany
| | - Jasper Anink
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Jolita Ciapaite
- Department of Genetics, Section Metabolic Diagnostics, University Medical Center Utrecht, 3584 EA Utrecht, the Netherlands
| | - Marjolein Bosma
- Department of Genetics, Section Metabolic Diagnostics, University Medical Center Utrecht, 3584 EA Utrecht, the Netherlands
| | - Ellen Stelloo
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Nalan Liv
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Paula Sobrevals Alcaraz
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands; Oncode Institute, Utrecht, the Netherlands
| | - Nanda M Verhoeven-Duif
- Department of Genetics, Section Metabolic Diagnostics, University Medical Center Utrecht, 3584 EA Utrecht, the Netherlands
| | - Judith J M Jans
- Department of Genetics, Section Metabolic Diagnostics, University Medical Center Utrecht, 3584 EA Utrecht, the Netherlands
| | - Harmjan R Vos
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands; Oncode Institute, Utrecht, the Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands; Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, the Netherlands
| | - Fried J T Zwartkruis
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands; Oncode Institute, Utrecht, the Netherlands.
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Zemlianski V, Marešová A, Princová J, Holič R, Häsler R, Ramos Del Río MJ, Lhoste L, Zarechyntsava M, Převorovský M. Nitrogen availability is important for preventing catastrophic mitosis in fission yeast. J Cell Sci 2024; 137:jcs262196. [PMID: 38780300 DOI: 10.1242/jcs.262196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 05/16/2024] [Indexed: 05/25/2024] Open
Abstract
Mitosis is a crucial stage in the cell cycle, controlled by a vast network of regulators responding to multiple internal and external factors. The fission yeast Schizosaccharomyces pombe demonstrates catastrophic mitotic phenotypes due to mutations or drug treatments. One of the factors provoking catastrophic mitosis is a disturbed lipid metabolism, resulting from, for example, mutations in the acetyl-CoA/biotin carboxylase (cut6), fatty acid synthase (fas2, also known as lsd1) or transcriptional regulator of lipid metabolism (cbf11) genes, as well as treatment with inhibitors of fatty acid synthesis. It has been previously shown that mitotic fidelity in lipid metabolism mutants can be partially rescued by ammonium chloride supplementation. In this study, we demonstrate that mitotic fidelity can be improved by multiple nitrogen sources. Moreover, this improvement is not limited to lipid metabolism disturbances but also applies to a number of unrelated mitotic mutants. Interestingly, the partial rescue is not achieved by restoring the lipid metabolism state, but rather indirectly. Our results highlight a novel role for nitrogen availability in mitotic fidelity.
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Affiliation(s)
- Viacheslav Zemlianski
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Anna Marešová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Jarmila Princová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Roman Holič
- Centre of Biosciences SAS, Institute of Animal Biochemistry and Genetics, Dúbravská cesta 9, 840 05 Bratislava, Slovak Republic
| | - Robert Häsler
- Center for Inflammatory Skin Diseases, Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Campus Kiel, Rosalind-Franklin-Straße 9, 24105 Kiel, Germany
| | - Manuel José Ramos Del Río
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Laurane Lhoste
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Maryia Zarechyntsava
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 128 00 Prague 2, Czechia
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5
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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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Murtaza N, Cheng AA, Brown CO, Meka DP, Hong S, Uy JA, El-Hajjar J, Pipko N, Unda BK, Schwanke B, Xing S, Thiruvahindrapuram B, Engchuan W, Trost B, Deneault E, Calderon de Anda F, Doble BW, Ellis J, Anagnostou E, Bader GD, Scherer SW, Lu Y, Singh KK. Neuron-specific protein network mapping of autism risk genes identifies shared biological mechanisms and disease-relevant pathologies. Cell Rep 2022; 41:111678. [DOI: 10.1016/j.celrep.2022.111678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/16/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022] Open
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Marker-free co-selection for successive rounds of prime editing in human cells. Nat Commun 2022; 13:5909. [PMID: 36207338 PMCID: PMC9546848 DOI: 10.1038/s41467-022-33669-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 09/27/2022] [Indexed: 11/18/2022] Open
Abstract
Prime editing enables the introduction of precise point mutations, small insertions, or short deletions without requiring donor DNA templates. However, efficiency remains a key challenge in a broad range of human cell types. In this work, we design a robust co-selection strategy through coediting of the ubiquitous and essential sodium/potassium pump (Na+/K+ ATPase). We readily engineer highly modified pools of cells and clones with homozygous modifications for functional studies with minimal pegRNA optimization. This process reveals that nicking the non-edited strand stimulates multiallelic editing but often generates tandem duplications and large deletions at the target site, an outcome dictated by the relative orientation of the protospacer adjacent motifs. Our approach streamlines the production of cell lines with multiple genetic modifications to create cellular models for biological research and lays the foundation for the development of cell-type specific co-selection strategies. Prime editing enables the introduction of precise point mutations, small insertions, or short deletions without requiring donor DNA templates. Here the authors develop a co-selection strategy to facilitate prime editing in human cells and provide design principles to prevent the formation of undesired editing byproducts at the target site.
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8
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Bielska AA, Harrigan CF, Kyung YJ, Morris Q, Palm W, Thompson CB. Activating mTOR Mutations Are Detrimental in Nutrient-Poor Conditions. Cancer Res 2022; 82:3263-3274. [PMID: 35857801 PMCID: PMC10094744 DOI: 10.1158/0008-5472.can-22-0121] [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: 01/13/2022] [Revised: 05/13/2022] [Accepted: 07/15/2022] [Indexed: 11/16/2022]
Abstract
The mTOR is a key regulator of cell growth that integrates growth factor signaling and nutrient availability and is a downstream effector of oncogenic receptor tyrosine kinases (RTK) and PI3K/Akt signaling. Thus, activating mTOR mutations would be expected to enhance growth in many tumor types. However, tumor sequencing data have shown that mTOR mutations are enriched only in renal clear cell carcinoma, a clinically hypervascular tumor unlikely to be constrained by nutrient availability. To further define this cancer-type-specific restriction, we studied activating mutations in mTOR. All mTOR mutants tested enhanced growth in a cell-type agnostic manner under nutrient-replete conditions but were detrimental to cell survival in nutrient-poor conditions. Consistently, analysis of tumor data demonstrated that oncogenic mutations in the nutrient-sensing arm of the mTOR pathway display a similar phenotype and were exceedingly rare in human cancers of all types. Together, these data suggest that maintaining the ability to turn off mTOR signaling in response to changing nutrient availability is retained in most naturally occurring tumors. SIGNIFICANCE This study suggests that cells need to inactivate mTOR to survive nutrient stress, which could explain the rarity of mTOR mutations and the limited clinical activity of mTOR inhibitors in cancer.
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Affiliation(s)
- Agata A. Bielska
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Caitlin F. Harrigan
- Department of Computer Science, University of Toronto, Toronto, ON, Canada
- Vector Institute, Toronto, Canada
| | - Yeon Ju Kyung
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Quaid Morris
- Department of Computer Science, University of Toronto, Toronto, ON, Canada
- Vector Institute, Toronto, Canada
- Computational and Systems Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Wilhelm Palm
- Cell Biology and Tumor Biology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Craig B. Thompson
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
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9
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Segreto R, Bazafkan H, Millinger J, Schenk M, Atanasova L, Doppler M, Büschl C, Boeckstaens M, Soto Diaz S, Schreiner U, Sillo F, Balestrini R, Schuhmacher R, Zeilinger S. The TOR kinase pathway is relevant for nitrogen signaling and antagonism of the mycoparasite Trichoderma atroviride. PLoS One 2022; 16:e0262180. [PMID: 34972198 PMCID: PMC8719763 DOI: 10.1371/journal.pone.0262180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/18/2021] [Indexed: 01/14/2023] Open
Abstract
Trichoderma atroviride (Ascomycota, Sordariomycetes) is a well-known mycoparasite applied for protecting plants against fungal pathogens. Its mycoparasitic activity involves processes shared with plant and human pathogenic fungi such as the production of cell wall degrading enzymes and secondary metabolites and is tightly regulated by environmental cues. In eukaryotes, the conserved Target of Rapamycin (TOR) kinase serves as a central regulator of cellular growth in response to nutrient availability. Here we describe how alteration of the activity of TOR1, the single and essential TOR kinase of T. atroviride, by treatment with chemical TOR inhibitors or by genetic manipulation of selected TOR pathway components affected various cellular functions. Loss of TSC1 and TSC2, that are negative regulators of TOR complex 1 (TORC1) in mammalian cells, resulted in altered nitrogen source-dependent growth of T. atroviride, reduced mycoparasitic overgrowth and, in the case of Δtsc1, a diminished production of numerous secondary metabolites. Deletion of the gene encoding the GTPase RHE2, whose mammalian orthologue activates mTORC1, led to rapamycin hypersensitivity and altered secondary metabolism, but had an only minor effect on vegetative growth and mycoparasitic overgrowth. The latter also applied to mutants missing the npr1-1 gene that encodes a fungus-specific kinase known as TOR target in yeast. Genome-wide transcriptome analysis confirmed TOR1 as a regulatory hub that governs T. atroviride metabolism and processes associated to ribosome biogenesis, gene expression and translation. In addition, mycoparasitism-relevant genes encoding terpenoid and polyketide synthases, peptidases, glycoside hydrolases, small secreted cysteine-rich proteins, and G protein coupled receptors emerged as TOR1 targets. Our results provide the first in-depth insights into TOR signaling in a fungal mycoparasite and emphasize its importance in the regulation of processes that critically contribute to the antagonistic activity of T. atroviride.
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Affiliation(s)
- Rossana Segreto
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Hoda Bazafkan
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Julia Millinger
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Martina Schenk
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Lea Atanasova
- Institute of Food Technology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Maria Doppler
- Department of Agrobiotechnology IFA-Tulln, Center for Analytical Chemistry, University of Natural, Resources and Life Sciences, Vienna (BOKU), Tulln, Austria
| | - Christoph Büschl
- Department of Agrobiotechnology IFA-Tulln, Center for Analytical Chemistry, University of Natural, Resources and Life Sciences, Vienna (BOKU), Tulln, Austria
| | - Mélanie Boeckstaens
- Département de Biologie Moléculaire, Laboratory of Biology of Membrane Transport, Université Libre de Bruxelles, Gosselies, Belgium
| | - Silvia Soto Diaz
- Département de Biologie Moléculaire, Laboratory of Biology of Membrane Transport, Université Libre de Bruxelles, Gosselies, Belgium
| | - Ulrike Schreiner
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | | | | | - Rainer Schuhmacher
- Department of Agrobiotechnology IFA-Tulln, Center for Analytical Chemistry, University of Natural, Resources and Life Sciences, Vienna (BOKU), Tulln, Austria
| | - Susanne Zeilinger
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
- * E-mail:
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10
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Carmignac V, Mignot C, Blanchard E, Kuentz P, Aubriot-Lorton MH, Parker VER, Sorlin A, Fraitag S, Courcet JB, Duffourd Y, Rodriguez D, Knox RG, Polubothu S, Boland A, Olaso R, Delepine M, Darmency V, Riachi M, Quelin C, Rollier P, Goujon L, Grotto S, Capri Y, Jacquemont ML, Odent S, Amram D, Chevarin M, Vincent-Delorme C, Catteau B, Guibaud L, Arzimanoglou A, Keddar M, Sarret C, Callier P, Bessis D, Geneviève D, Deleuze JF, Thauvin C, Semple RK, Philippe C, Rivière JB, Kinsler VA, Faivre L, Vabres P. Clinical spectrum of MTOR-related hypomelanosis of Ito with neurodevelopmental abnormalities. Genet Med 2021; 23:1484-1491. [PMID: 33833411 PMCID: PMC8354853 DOI: 10.1038/s41436-021-01161-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Hypomelanosis of Ito (HI) is a skin marker of somatic mosaicism. Mosaic MTOR pathogenic variants have been reported in HI with brain overgrowth. We sought to delineate further the pigmentary skin phenotype and clinical spectrum of neurodevelopmental manifestations of MTOR-related HI. METHODS From two cohorts totaling 71 patients with pigmentary mosaicism, we identified 14 patients with Blaschko-linear and one with flag-like pigmentation abnormalities, psychomotor impairment or seizures, and a postzygotic MTOR variant in skin. Patient records, including brain magnetic resonance image (MRI) were reviewed. Immunostaining (n = 3) for melanocyte markers and ultrastructural studies (n = 2) were performed on skin biopsies. RESULTS MTOR variants were present in skin, but absent from blood in half of cases. In a patient (p.[Glu2419Lys] variant), phosphorylation of p70S6K was constitutively increased. In hypopigmented skin of two patients, we found a decrease in stage 4 melanosomes in melanocytes and keratinocytes. Most patients (80%) had macrocephaly or (hemi)megalencephaly on MRI. CONCLUSION MTOR-related HI is a recognizable neurocutaneous phenotype of patterned dyspigmentation, epilepsy, intellectual deficiency, and brain overgrowth, and a distinct subtype of hypomelanosis related to somatic mosaicism. Hypopigmentation may be due to a defect in melanogenesis, through mTORC1 activation, similar to hypochromic patches in tuberous sclerosis complex.
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Affiliation(s)
- Virginie Carmignac
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France.
- MAGEC-Mosaïque Reference Center, Dijon University Hospital, Dijon, France.
| | - Cyril Mignot
- Neuropaediatrics and Development Pathology Department, Trousseau Hospital, AP-HP, Paris, France
- Genetics Department and Reference Center for rare causes of Intellectual Disability, Pitié-Salpêtrière hospital, AP-HP, Paris, France
| | - Emmanuelle Blanchard
- Plateforme IBiSA de Microscopie Electronique, Anatomie et cytologie pathologique, Université et CHRU de Tours, Tours, France
- INSERM U1259 MAVIVH, Université et CHRU de Tours, Tours, France
| | - Paul Kuentz
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
| | | | - Victoria E R Parker
- The University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, UK
| | - Arthur Sorlin
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
- Pediatrics and Medical Genetics Department, Dijon-Bourgogne University Hospital, Dijon, France
| | - Sylvie Fraitag
- Service d'Anatomie et Cytologie Pathologique, Necker-Enfants Malades Hospital, Paris, France
| | - Jean-Benoît Courcet
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
- Pediatrics and Medical Genetics Department, Dijon-Bourgogne University Hospital, Dijon, France
| | - Yannis Duffourd
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
| | - Diana Rodriguez
- Genetics Department and Reference Center for rare causes of Intellectual Disability, Pitié-Salpêtrière hospital, AP-HP, Paris, France
| | - Rachel G Knox
- The University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, UK
| | - Satyamaanasa Polubothu
- Paediatric Dermatology, Great Ormond St Hospital for Children NHS Foundation Trust, London, UK
- UCL GOS Institute of Child Health, London, UK
- Mosaicism and Precision Medicine laboratory, Francis Crick Institute, London, UK
| | - Anne Boland
- National Genotyping Center, Genomic Institute, CEA, Evry, France
| | - Robert Olaso
- National Genotyping Center, Genomic Institute, CEA, Evry, France
| | - Marc Delepine
- National Genotyping Center, Genomic Institute, CEA, Evry, France
| | - Véronique Darmency
- Pediatrics and Medical Genetics Department, Dijon-Bourgogne University Hospital, Dijon, France
| | - Melissa Riachi
- UCL GOS Institute of Child Health, London, UK
- Mosaicism and Precision Medicine laboratory, Francis Crick Institute, London, UK
| | - Chloé Quelin
- Clinical Genetics department, Rennes University Hospital, Rennes, France
| | - Paul Rollier
- Clinical Genetics department, Rennes University Hospital, Rennes, France
| | - Louise Goujon
- Clinical Genetics department, Rennes University Hospital, Rennes, France
| | - Sarah Grotto
- Genetics Department, AP-HP, Robert-Debré University Hospital, Paris, France
| | - Yline Capri
- Genetics Department, AP-HP, Robert-Debré University Hospital, Paris, France
| | | | - Sylvie Odent
- Clinical Genetics department, Rennes University Hospital, Rennes, France
| | - Daniel Amram
- Clinical Genetics Department, Créteil Hospital, Créteil, France
| | - Martin Chevarin
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Unité Fonctionnelle Innovation en Diagnostic Génomique des Maladies Rares, FHU-TRANSLAD, CHU Dijon Bourgogne University Hospital, Dijon, France
| | | | - Benoît Catteau
- Dermatology department, Lille University Hospital, Lille, France
| | - Laurent Guibaud
- Pediatric and Fetal Imaging Department, Hospices Civils de Lyon, Bron, France
| | - Alexis Arzimanoglou
- Department of Paediatric Clinical Epileptology, Sleep Disorders and Functional Neurology, University Hospitals of Lyon (HCL), Lyon, France
- Brain Dynamics and Cognition (DYCOG) Team, Lyon Neuroscience Research Centre, Lyon, France
| | - Malika Keddar
- Cytogenetics Department, Dijon University Hospital, Dijon, France
| | - Catherine Sarret
- Medical genetics department, Pôle Femme et Enfant, Clermont-Ferrand University Hospital-Hôpital d'Estaing, Clermont-Ferrand, France
| | - Patrick Callier
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
- Cytogenetics Department, Dijon University Hospital, Dijon, France
| | - Didier Bessis
- Dermatology Department, Montpellier University Hospital, Montpellier, France
| | - David Geneviève
- Medical Genetics Department, Montpellier University Hospital, Montpellier, France
| | | | - Christel Thauvin
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
- Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon, France
| | - Robert K Semple
- The University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, UK
- Center for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | | | - Jean-Baptiste Rivière
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
| | - Veronica A Kinsler
- Paediatric Dermatology, Great Ormond St Hospital for Children NHS Foundation Trust, London, UK
- UCL GOS Institute of Child Health, London, UK
- Mosaicism and Precision Medicine laboratory, Francis Crick Institute, London, UK
| | - Laurence Faivre
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon, France
| | - Pierre Vabres
- INSERM UMR1231, Bourgogne Franche-Comté University, Dijon, France
- MAGEC-Mosaïque Reference Center, Dijon University Hospital, Dijon, France
- Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), Dijon-Burgundy University Hospital, Dijon, France
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11
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Luo X, Yin J, Miao S, Feng W, Ning T, Xu S, Huang S, Zhang S, Liao Y, Hao C, Wu B, Ma D. mTORC1 promotes mineralization via p53 pathway. FASEB J 2021; 35:e21325. [PMID: 33508145 DOI: 10.1096/fj.202002016r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/04/2020] [Accepted: 12/14/2020] [Indexed: 12/30/2022]
Abstract
The objectives of our study were to investigate the roles of mTORC1 in odontoblast proliferation and mineralization and to determine the mechanism by which mTORC1 regulates odontoblast mineralization. In vitro, MDPC23 cells were treated with rapamycin (10 nmol/L) and transfected with a lentivirus for short hairpin (shRNA)-mediated silencing of the tuberous sclerosis complex (shTSC1) to inhibit and activate mTORC1, respectively. CCK8 assays, flow cytometry, Alizarin red S staining, ALP staining, qRT-PCR, and western blot analysis were performed. TSC1-conditional knockout (DMP1-Cre+ ; TSC1f/f , hereafter CKO) mice and littermate control (DMP1-Cre- ; TSC1f/f , hereafter WT) mice were generated. H&E staining, immunofluorescence, and micro-CT analysis were performed. Transcriptome sequencing analysis was used to screen the mechanism of this process. mTORC1 inactivation decreased the cell proliferation. The qRT-PCR and western blot results showed that mineralization-related genes and proteins were downregulated in mTORC1-inactivated cells. Moreover, mTORC1 overactivation promoted cell proliferation and mineralization-related gene and protein expression. In vivo, the micro-CT results showed that DV/TV and dentin thickness were higher in CKO mice than in controls and H&E staining showed the same results. Mineralization-related proteins expression was upregulated. Transcriptome sequencing analysis revealed that p53 pathway-associated genes were differentially expressed in TSC1-deficient cells. By inhibiting p53 alone or both mTORC1 and p53 with rapamycin and a p53 inhibitor, we elucidated that p53 acts downstream of mTORC1 and that mTORC1 thereby promotes odontoblast mineralization. Taken together, our findings demonstrate that the role of mTORC1 in odontoblast proliferation and mineralization, and confirm that mTORC1 upregulates odontoblast mineralization via the p53 pathway.
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Affiliation(s)
- Xinghong Luo
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,College of Stomatology, Southern Medical University, Guangzhou, China
| | - Jingyao Yin
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,College of Stomatology, Southern Medical University, Guangzhou, China
| | - Shenghong Miao
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,College of Stomatology, Southern Medical University, Guangzhou, China
| | - Weiqing Feng
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,College of Stomatology, Southern Medical University, Guangzhou, China
| | - Tingting Ning
- College of Stomatology, Southern Medical University, Guangzhou, China.,Department of Endodontics, Stomatology Hospital, Southern Medical University, Guangzhou, China
| | - Shuaimei Xu
- College of Stomatology, Southern Medical University, Guangzhou, China.,Department of Endodontics, Stomatology Hospital, Southern Medical University, Guangzhou, China
| | - Shijiang Huang
- Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Sheng Zhang
- Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Yunjun Liao
- Department of Plastic and Cosmetic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Chunbo Hao
- Department of Stomatology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Buling Wu
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,College of Stomatology, Southern Medical University, Guangzhou, China
| | - Dandan Ma
- Department of Endodontics, Stomatology Hospital, Southern Medical University, Guangzhou, China.,Department of Advanced Oral Sciences & Therapeutics, University of Maryland School of Dentistry, Baltimore, MD, USA
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12
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Corral-Ramos C, Barrios R, Ayté J, Hidalgo E. TOR and MAP kinase pathways synergistically regulate autophagy in response to nutrient depletion in fission yeast. Autophagy 2021; 18:375-390. [PMID: 34157946 DOI: 10.1080/15548627.2021.1935522] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
General autophagy is an evolutionarily conserved process in eukaryotes, by which intracellular materials are transported into and degraded inside lysosomes or vacuoles, with the main goal of recycling those materials during periods of starvation. The molecular bases of autophagy have been widely described in Saccharomyces cerevisiae, and the specific roles of Atg proteins in the process were first characterized in this model system. Important contributions have been made in Schizosaccharomyces pombe highlighting the evolutionary similarity and, at the same time, diversity of Atg components in autophagy. However, little is known regarding signals, pathways and role of autophagy in this distant yeast. Here, we undertake a global approach to investigate the signals, the pathways and the consequences of autophagy activation. We demonstrate that not only nitrogen but several nutritional deprivations including lack of carbon, sulfur, phosphorus or leucine sources, trigger autophagy, and that the TORC1, TORC2 and MAP kinase Sty1 pathways control the onset of autophagy. Furthermore, we identify an unexpected phenotype of autophagy-defective mutants, namely their inability to survive in the absence of leucine when biosynthesis of this amino acid is impaired.Abbreviations: ATG: autophagy-related; cAMP: cyclic adenosine monophosphate; cDNA: complementary deoxyribonucleic acid; GFP: green fluorescence protein; Gluc: glucose; Leu: leucine; MAP: mitogen-activated protein; MM: minimal medium; PI: propidium iodine; PKA: protein kinase A; RNA: ribonucleic acid; RT-qPCR: real time quantitative polymerase chain reaction; S. cerevisiae: Saccharomyces cerevisiae; S. pombe: Schizosaccharomyces pombe; TCA: trichloroacetic acid; TOR: target of rapamycin; TORC1: target of rapamycin complex 1; TORC2: target of rapamycin complex 2; YE5S: yeast extract 5 amino acid supplemented.
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Affiliation(s)
| | - Rubén Barrios
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
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13
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Xiao B, Zuo D, Hirukawa A, Cardiff RD, Lamb R, Sonenberg N, Muller WJ. Rheb1-Independent Activation of mTORC1 in Mammary Tumors Occurs through Activating Mutations in mTOR. Cell Rep 2021; 31:107571. [PMID: 32348753 DOI: 10.1016/j.celrep.2020.107571] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 12/06/2019] [Accepted: 04/02/2020] [Indexed: 11/25/2022] Open
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) is a master modulator of cellular growth, and its aberrant regulation is recurrently documented within breast cancer. While the small GTPase Rheb1 is the canonical activator of mTORC1, Rheb1-independent mechanisms of mTORC1 activation have also been reported but have not been fully understood. Employing multiple transgenic mouse models of breast cancer, we report that ablation of Rheb1 significantly impedes mammary tumorigenesis. In the absence of Rheb1, a block in tumor initiation can be overcome by multiple independent mutations in Mtor to allow Rheb1-independent reactivation of mTORC1. We further demonstrate that the mTOR kinase is indispensable for tumor initiation as the genetic ablation of mTOR abolishes mammary tumorigenesis. Collectively, our findings demonstrate that mTORC1 activation is indispensable for mammary tumor initiation and that tumors acquire alternative mechanisms of mTORC1 activation.
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Affiliation(s)
- Bin Xiao
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind & Morris Goodman Cancer Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Dongmei Zuo
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind & Morris Goodman Cancer Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Alison Hirukawa
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind & Morris Goodman Cancer Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Robert D Cardiff
- Center for Comparative Medicine, University of California, Davis, Davis, CA 95616, USA
| | | | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Faculty of Medicine, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind & Morris Goodman Cancer Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - William J Muller
- Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Faculty of Medicine, McGill University, Montreal, QC H3A 1A3, Canada; Rosalind & Morris Goodman Cancer Centre, McGill University, Montreal, QC H3A 1A3, Canada.
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14
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da Silva Rosa SC, Martens MD, Field JT, Nguyen L, Kereliuk SM, Hai Y, Chapman D, Diehl-Jones W, Aliani M, West AR, Thliveris J, Ghavami S, Rampitsch C, Dolinsky VW, Gordon JW. BNIP3L/Nix-induced mitochondrial fission, mitophagy, and impaired myocyte glucose uptake are abrogated by PRKA/PKA phosphorylation. Autophagy 2020; 17:2257-2272. [PMID: 33044904 PMCID: PMC8496715 DOI: 10.1080/15548627.2020.1821548] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Lipotoxicity is a form of cellular stress caused by the accumulation of lipids resulting in mitochondrial dysfunction and insulin resistance in muscle. Previously, we demonstrated that the mitophagy receptor BNIP3L/Nix is responsive to lipotoxicity and accumulates in response to a high-fat (HF) feeding. To provide a better understanding of this observation, we undertook gene expression array and shot-gun metabolomics studies in soleus muscle from rodents on an HF diet. Interestingly, we observed a modest reduction in several autophagy-related genes. Moreover, we observed alterations in the fatty acyl composition of cardiolipins and phosphatidic acids. Given the reported roles of these phospholipids and BNIP3L in mitochondrial dynamics, we investigated aberrant mitochondrial turnover as a mechanism of impaired myocyte insulin signaling. In a series of gain-of-function and loss-of-function experiments in rodent and human myotubes, we demonstrate that BNIP3L accumulation triggers mitochondrial depolarization, calcium-dependent activation of DNM1L/DRP1, and mitophagy. In addition, BNIP3L can inhibit insulin signaling through activation of MTOR-RPS6KB/p70S6 kinase inhibition of IRS1, which is contingent on phosphatidic acids and RHEB. Finally, we demonstrate that BNIP3L-induced mitophagy and impaired glucose uptake can be reversed by direct phosphorylation of BNIP3L by PRKA/PKA, leading to the translocation of BNIP3L from the mitochondria and sarcoplasmic reticulum to the cytosol. These findings provide insight into the role of BNIP3L, mitochondrial turnover, and impaired myocyte insulin signaling during an overfed state when overall autophagy-related gene expression is reduced. Furthermore, our data suggest a mechanism by which exercise or pharmacological activation of PRKA may overcome myocyte insulin resistance. Abbreviations: BCL2: B cell leukemia/lymphoma 2; BNIP3L/Nix: BCL2/adenovirus E1B interacting protein 3-like; DNM1L/DRP1: dynamin 1-like; FUNDC1: FUN14 domain containing 1; IRS1: insulin receptor substrate 1; MAP1LC3A/LC3: microtubule-associated protein 1 light chain 3 alpha; MFN1: mitofusin 1; MFN2: mitofusin 2; MTOR: mechanistic target of rapamycin kinase; OPA1: OPA1 mitochondrial dynamin like GTPase; PDE4i: phosphodiesterase 4 inhibitor; PLD1: phospholipase D1; PLD6: phospholipase D family member 6; PRKA/PKA: protein kinase, AMP-activated; PRKCD/PKCδ: protein kinase C, delta; PRKCQ/PKCθ: protein kinase C, theta; RHEB: Ras homolog enriched in brain; RPS6KB/p70S6K: ribosomal protein S6 kinase; SQSTM1/p62: sequestosome 1; YWHAB/14-3-3β: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein beta
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Affiliation(s)
- Simone C da Silva Rosa
- Departments of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.,The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Matthew D Martens
- Departments of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.,The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Jared T Field
- Departments of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.,The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Lucas Nguyen
- The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Canada
| | - Stephanie M Kereliuk
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada.,The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Yan Hai
- Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Donald Chapman
- Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - William Diehl-Jones
- Department of Biological Science, University of Manitoba, Winnipeg, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada.,Faculty of Health Disciplines, Athabasca University, Edmonton, Canada
| | - Michel Aliani
- Department of Human Nutritional Science, University of Manitoba, Winnipeg, Canada
| | - Adrian R West
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - James Thliveris
- Departments of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada
| | - Saeid Ghavami
- Departments of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | | | - Vernon W Dolinsky
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada.,The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
| | - Joseph W Gordon
- Departments of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.,College of Nursing, University of Manitoba, Winnipeg, Canada.,The Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Canada.,Children's Hospital Research Institute of Manitoba, Winnipeg, Canada
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15
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Matsuda S, Kikkawa U, Uda H, Nakashima A. The S. pombe CDK5 ortholog Pef1 regulates sexual differentiation through control of the TORC1 pathway and autophagy. J Cell Sci 2020; 133:jcs247817. [PMID: 32788233 DOI: 10.1242/jcs.247817] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022] Open
Abstract
In Schizosaccharomyces pombe, a general strategy for survival in response to environmental changes is sexual differentiation, which is triggered by TORC1 inactivation. However, mechanisms of TORC1 regulation in fission yeast remain poorly understood. In this study, we found that Pef1, which is an ortholog of mammalian CDK5, regulates the initiation of sexual differentiation through positive regulation of TORC1 activity. Conversely, deletion of pef1 leads to activation of autophagy and subsequent excessive TORC1 reactivation during the early phases of the nitrogen starvation response. This excessive TORC1 reactivation results in the silencing of the Ste11-Mei2 pathway and mating defects. Additionally, we found that pef1 genetically interacts with tsc1 and tsc2 for TORC1 regulation, and physically interacts with three cyclins, Clg1, Pas1 and Psl1. The double deletion of clg1 and pas1 promotes activation of autophagy and TORC1 during nitrogen starvation, similar to what is seen in pef1Δ cells. Overall, our work suggests that Pef1-Clg1 and Pef1-Pas1 complexes regulate initiation of sexual differentiation through control of the TSC-TORC1 pathway and autophagy.
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Affiliation(s)
- Shinya Matsuda
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan
| | - Ushio Kikkawa
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
- Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Haruka Uda
- Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Akio Nakashima
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
- Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
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16
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Hadouiri N, Darmency V, Guibaud L, Arzimanoglou A, Sorlin A, Carmignac V, Rivière JB, Huet F, Luu M, Bardou M, Thauvin-Robinet C, Vabres P, Faivre L. Compassionate use of everolimus for refractory epilepsy in a patient with MTOR mosaic mutation. Eur J Med Genet 2020; 63:104036. [PMID: 32805448 DOI: 10.1016/j.ejmg.2020.104036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/16/2020] [Accepted: 08/08/2020] [Indexed: 10/23/2022]
Abstract
The MTOR gene encodes the mechanistic target of rapamycin (mTOR), which is a core component of the PI3K-AKT-mTOR signaling pathway. Postzygotic MTOR variants result in various mosaic phenotypes, referred to in OMIM as Smith-Kinsgmore syndrome or focal cortical dysplasia. We report here the case of a patient, with an MTOR mosaic gain-of-function variant (p.Glu2419Lys) in the DNA of 41% skin cells, who received compassionate off-label treatment with everolimus for refractory epilepsy. This 12-year-old-girl presented with psychomotor regression, intractable seizures, hypopigmentation along Blaschko's lines (hypomelanosis of Ito), asymmetric regional body overgrowth, and ocular anomalies, as well as left cerebral hemispheric hypertrophy with some focal underlying migration disorders. In response to the patient's increasingly frequent epileptic seizures, everolimus was initiated (after approval from the hospital ethics committee) at 5 mg/day and progressively increased to 12.5 mg/day. After 5 months of close monitoring (including neuropsychological and electroencephalographic assessment), no decrease in seizure frequency was observed. Though the physiopathological rationale was good, no significant clinical response was noticed under everolimus treatment. A clinical trial would be needed to draw conclusions, but, because the phenotype is extremely rare, it would certainly need to be conducted on an international scale.
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Affiliation(s)
- Nawale Hadouiri
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Veronique Darmency
- Service de Neurophysiologie Clinique, Hôpital d'Enfants, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Laurent Guibaud
- Radiologie Pédiatrique, Hôpital Femme Mère Enfant (HFME), Bron, France
| | - Alexis Arzimanoglou
- Service d'épileptologie Clinique, des Troubles du Sommeil et de Neurologie Fonctionnelle de l'enfant, Coordinateur du Réseau Européen pour les épilepsies Rares et Complexes, ERN EpiCARE, HCL - GH Est, Hôpital Femme Mère Enfant, Bron, France
| | - Arthur Sorlin
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, CHU Dijon Bourgogne, 21079, Dijon, France; Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France
| | - Virginie Carmignac
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France
| | - Jean-Baptiste Rivière
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France
| | - Frédéric Huet
- Service de Neurophysiologie Clinique, Hôpital d'Enfants, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Maxime Luu
- Centre d'Investigation Clinique Plurithématique, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Marc Bardou
- Centre d'Investigation Clinique Plurithématique, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Christel Thauvin-Robinet
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France; Centre de Référence Déficiences Intellectuelles de Causes Rares Défi-Bourgogne, CHU Dijon Bourgogne, 21079, Dijon, France
| | - Pierre Vabres
- Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France; Centre de Référence des Maladies Rares de la Peau et des Muqueuses d'origine Génétique (MAGEC), CHU Dijon Bourgogne, 21079, Dijon, France
| | - Laurence Faivre
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, CHU Dijon Bourgogne, 21079, Dijon, France; Génétique des Anomalies du Développement, UMR1231, Université de Bourgogne, 21079, Dijon, France; Fédération Hospitalo-Universitaire Médecine Translationnelle et Anomalies du Développement (TRANSLAD), CHU Dijon Bourgogne, 21079, Dijon, France.
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17
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Du LL. Resurrection from lethal knockouts: Bypass of gene essentiality. Biochem Biophys Res Commun 2020; 528:405-412. [PMID: 32507598 DOI: 10.1016/j.bbrc.2020.05.207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 05/27/2020] [Indexed: 01/03/2023]
Abstract
Understanding genotype-phenotype relationships is a central pursuit in biology. Gene knockout generates a complete loss-of-function genotype and is a commonly used approach for probing gene functions. The most severe phenotypic consequence of gene knockout is lethality. Genes with a lethal knockout phenotype are called essential genes. Based on genome-wide knockout analyses in yeasts, up to approximately a quarter of genes in a genome can be essential. Like other genotype-phenotype relationships, gene essentiality is subject to background effects and can vary due to gene-gene interactions. In particular, for some essential genes, lethality caused by knockout can be rescued by extragenic suppressors. Such "bypass of essentiality" (BOE) gene-gene interactions have been an understudied type of genetic suppression. A recent systematic analysis revealed that, remarkably, the essentiality of nearly 30% of essential genes in the fission yeast Schizosaccharomyces pombe can be bypassed by BOE interactions. Here, I review the history and recent progress on uncovering and understanding the bypass of gene essentiality.
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Affiliation(s)
- Li-Lin Du
- National Institute of Biological Sciences, Beijing, 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China.
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18
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Tarkowski B, Kuchcinska K, Blazejczyk M, Jaworski J. Pathological mTOR mutations impact cortical development. Hum Mol Genet 2020; 28:2107-2119. [PMID: 30789219 DOI: 10.1093/hmg/ddz042] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 02/03/2023] Open
Abstract
Several mosaic mutations of the mammalian/mechanistic target of rapamycin (mTOR) have recently been found in patients with cortical malformations, such as hemimegalencephaly (HME) and focal cortical dysplasia (FCD). Although all of them should activate mTOR signaling, comparisons of the impact of different mTOR mutations on brain development have been lacking. Also it remains unknown if any potential differences these mutations may have on cortical development are directly related to a degree of mTOR signaling increase. The present study assessed levels of mTORC1 pathway activity in cell lines and rat primary neurons overexpressing several mTOR mutants that were previously found in HME, FCD, cancer patients and in vitro mutagenesis screens. Next we introduced the mutants, enhancing mTORC1 signaling most potently, into developing mouse brains and assessed electroporated cell morphology and migratory phenotype using immunofluorescent staining. We observed the differential inhibition of neuronal progenitor cortical migration, which partly corresponded with a degree of mTORC1 signaling enhancement these mutants induced in cultured cells. The most potent quadruple mutant prevented most of the progenitors from entering the cortical plate. Cells that expressed less potent, single-point, mTOR mutants entered the cortical plate but failed to reach its upper layers and had enlarged soma. Our findings suggest a correlation between the potency of mTOR mutation to activate mTORC1 pathway and disruption of cortical migration.
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Affiliation(s)
- Bartosz Tarkowski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Kinga Kuchcinska
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | | | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
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19
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Schröder A, Aitken KJ, Jiang JX, Sidler M, Tölg C, Siebenaller A, Jeffrey N, Kirwan T, Leslie B, Wu C, Weksberg R, Delgado-Olguin P, Bägli DJ. Persistent myopathy despite release of partial obstruction: in vivo reversal of dysfunction and transcriptional responses using rapamycin. FASEB J 2020; 34:3594-3615. [PMID: 31984552 DOI: 10.1096/fj.201900547rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 12/12/2022]
Abstract
Current and potential medical therapy for obstruction-induced myopathic bladder dysfunction (from benign prostatic hyperplasia or posterior urethral valves) focuses on symptoms. The persistent tissue pathology and dysfunction after release of obstruction is often deemed irreversible without any systematic therapeutic approaches. As rapamycin can attenuate bladder smooth muscle hypertrophy and dysfunction during the genesis of partial obstruction in vivo, we tested whether rapamycin could improve persistent function after release of obstruction (de-obstruction or REL). Female Sprague-Dawley rat bladders were partially obstructed (PBO) by suturing around both the urethra and a para-urethral steel rod, then removing the rod. One day prior to release of obstruction (preREL), voiding parameters and residual urine volume of preREL+future rapa, preREL+future veh groups were recorded. Release of obstruction (REL) was performed by suture removal following 6 weeks of PBO. For 4 more weeks after the de-obstruction, REL animals were randomized to rapamycin (REL+rapa) or vehicle (REL+veh). PBO for 6 weeks were used as positive controls. In shams, the urethra was exposed, but no suture tied. Voiding parameters and residual urine volume were measured prior to sacrifice of sham and REL+veh or REL+rapa, and PBO. Rapamycin efficacy was tested by pair-wise comparison of changes in individual voiding data from preREL+future veh or preREL+future rapa versus REL+veh or REL+rapa, respectively, as well as by comparisons of REL+veh to REL+rapa groups. Bladders were weighed and processed for a high-throughput QPCR array, and histopathology. Bladder/body mass ratios with PBO increased significantly and remained higher in the release phase in REL+veh animals. REL+rapa versus REL+veh improved residual volumes and micturition fractions toward sham levels. Three genes encoding extracellular proteins, BMP2, SOD3, and IGFBP7, correlated with functional improvement by Pearson's correlations. The promoters of these genes showed enrichment for several motifs including circadian E-boxes. While obstruction and REL augmented CLOCK and NPAS2 expression above sham levels, rapamycin treatment during release significantly blocked their expression. This experimental design of pharmaco-intervention during the de-obstruction phase revealed a novel pathway dysregulated during the clinically relevant treatment phase of obstructive bladder myopathy.
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Affiliation(s)
- Annette Schröder
- Urology Division, Department of Surgery, Hospital for Sick Children, Toronto, ON, Canada.,Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Karen J Aitken
- Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Jia-Xin Jiang
- Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Martin Sidler
- Urology Division, Department of Surgery, Hospital for Sick Children, Toronto, ON, Canada.,Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Cornelia Tölg
- Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Aliza Siebenaller
- Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Nefateri Jeffrey
- Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Tyler Kirwan
- Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Bruno Leslie
- Urology Division, Department of Surgery, Hospital for Sick Children, Toronto, ON, Canada.,Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Changhao Wu
- Department of Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Rosanna Weksberg
- Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Paul Delgado-Olguin
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada.,Heart & Stroke Richard Lewar Centre of Excellence in Cardiovascular Research, Toronto, ON, Canada
| | - Darius J Bägli
- Urology Division, Department of Surgery, Hospital for Sick Children, Toronto, ON, Canada.,Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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20
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Nussinov R, Tsai C, Jang H. Autoinhibition can identify rare driver mutations and advise pharmacology. FASEB J 2019; 34:16-29. [DOI: 10.1096/fj.201901341r] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/18/2019] [Accepted: 10/09/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section Basic Science Program Frederick National Laboratory for Cancer Research Frederick MD USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Chung‐Jung Tsai
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Hyunbum Jang
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
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21
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Murugan AK. mTOR: Role in cancer, metastasis and drug resistance. Semin Cancer Biol 2019; 59:92-111. [PMID: 31408724 DOI: 10.1016/j.semcancer.2019.07.003] [Citation(s) in RCA: 318] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 06/14/2019] [Accepted: 07/03/2019] [Indexed: 02/09/2023]
Abstract
Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that gets inputs from the amino acids, nutrients, growth factor, and environmental cues to regulate varieties of fundamental cellular processes which include protein synthesis, growth, metabolism, aging, regeneration, autophagy, etc. The mTOR is frequently deregulated in human cancer and activating somatic mutations of mTOR were recently identified in several types of human cancer and hence mTOR is therapeutically targeted. mTOR inhibitors were commonly used as immunosuppressors and currently, it is approved for the treatment of human malignancies. This review briefly focuses on the structure and biological functions of mTOR. It extensively discusses the genetic deregulation of mTOR including amplifications and somatic mutations, mTOR-mediated cell growth promoting signaling, therapeutic targeting of mTOR and the mechanisms of resistance, the role of mTOR in precision medicine and other recent advances in further understanding the role of mTOR in cancer.
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Affiliation(s)
- Avaniyapuram Kannan Murugan
- Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, PO Box 3354, Research Center (MBC 03), Riyadh, 11211, Saudi Arabia.
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22
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Murugan AK, Liu R, Xing M. Identification and characterization of two novel oncogenic mTOR mutations. Oncogene 2019; 38:5211-5226. [PMID: 30918329 PMCID: PMC6597304 DOI: 10.1038/s41388-019-0787-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 02/12/2019] [Accepted: 03/07/2019] [Indexed: 12/29/2022]
Abstract
Mammalian target of rapamycin (mTOR) signaling is often aberrantly activated, particularly when genetically altered, in human cancers. mTOR inhibitors targeting the activated mTOR signaling are highly promising anti-cancer drugs. Knowing the activating genetic change in mTOR can help guide the use of mTOR inhibitors for cancer treatment. This study was conducted to identify and characterize novel oncogenic mTOR mutations that can potentially be therapeutic targets in human cancer. We sequenced 30 exons of the mTOR gene in 12 thyroid cancer cell lines, 3 melanoma cell lines, 20 anaplastic thyroid cancer (ATC) tumors, and 23 melanoma tumors and functionally characterized the identified novel mTOR mutations in vitro and in vivo. We identified a novel point mutation A1256G in ATC cell line and G7076A in melanoma tumor in exon 9 and exon 51 of the mTOR gene, respectively. Over-expression of the corresponding mTOR mutants H419R and G2359E created through induced mutagenesis showed markedly elevated protein kinase activities associated with the activation of mTOR/p70S6K signaling in HEK293T cells. Stable expression of the two mTOR mutants in NIH3T3 cells strongly activated the mTOR/p70S6K signaling pathway and induced morphologic transformation, cell focus formation, anchorage-independent cell growth, and invasion. Inoculation of these mutant-expressing cells in athymic nude mice induced rapid tumor development, showing their driving oncogenicity. We also demonstrated that transfection with the novel mutants conferred cells high sensitivities to the mTOR inhibitor temsirolimus. We speculate that human cancers harboring these mTOR mutations, such as ATC and melanoma, may be effectively treated with inhibitors targeting mTOR.
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Affiliation(s)
- Avaniyapuram Kannan Murugan
- Laboratory for Cellular and Molecular Thyroid Research, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Rengyun Liu
- Laboratory for Cellular and Molecular Thyroid Research, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Mingzhao Xing
- Laboratory for Cellular and Molecular Thyroid Research, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
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23
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Li S, Song Y, Quach C, Guo H, Jang GB, Maazi H, Zhao S, Sands NA, Liu Q, In GK, Peng D, Yuan W, Machida K, Yu M, Akbari O, Hagiya A, Yang Y, Punj V, Tang L, Liang C. Transcriptional regulation of autophagy-lysosomal function in BRAF-driven melanoma progression and chemoresistance. Nat Commun 2019; 10:1693. [PMID: 30979895 PMCID: PMC6461621 DOI: 10.1038/s41467-019-09634-8] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 03/21/2019] [Indexed: 02/07/2023] Open
Abstract
Autophagy maintains homeostasis and is induced upon stress. Yet, its mechanistic interaction with oncogenic signaling remains elusive. Here, we show that in BRAFV600E-melanoma, autophagy is induced by BRAF inhibitor (BRAFi), as part of a transcriptional program coordinating lysosome biogenesis/function, mediated by the TFEB transcription factor. TFEB is phosphorylated and thus inactivated by BRAFV600E via its downstream ERK independently of mTORC1. BRAFi disrupts TFEB phosphorylation, allowing its nuclear translocation, which is synergized by increased phosphorylation/inactivation of the ZKSCAN3 transcriptional repressor by JNK2/p38-MAPK. Blockade of BRAFi-induced transcriptional activation of autophagy-lysosomal function in melanoma xenografts causes enhanced tumor progression, EMT-transdifferentiation, metastatic dissemination, and chemoresistance, which is associated with elevated TGF-β levels and enhanced TGF-β signaling. Inhibition of TGF-β signaling restores tumor differentiation and drug responsiveness in melanoma cells. Thus, the "BRAF-TFEB-autophagy-lysosome" axis represents an intrinsic regulatory pathway in BRAF-mutant melanoma, coupling BRAF signaling with TGF-β signaling to drive tumor progression and chemoresistance.
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Affiliation(s)
- Shun Li
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400044, China
| | - Ying Song
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Christine Quach
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Hongrui Guo
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- College of Veterinary Medicine, Sichuan Agriculture University, Chengdu, 611130, China
| | - Gyu-Beom Jang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Hadi Maazi
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Shihui Zhao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Nathaniel A Sands
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Qingsong Liu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, 350 Shushan Hu Road, Hefei, 230031, China
| | - Gino K In
- Norris Comprehensive Cancer, Division of Oncology, University of Southern California, Los Angeles, CA, 90033, USA
| | - David Peng
- Department of Dermatology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Weiming Yuan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Keigo Machida
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Min Yu
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Omid Akbari
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Ashley Hagiya
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Yongfei Yang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Vasu Punj
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Liling Tang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400044, China.
| | - Chengyu Liang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
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24
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Systematic analysis reveals the prevalence and principles of bypassable gene essentiality. Nat Commun 2019; 10:1002. [PMID: 30824696 PMCID: PMC6397241 DOI: 10.1038/s41467-019-08928-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/07/2019] [Indexed: 12/12/2022] Open
Abstract
Gene essentiality is a variable phenotypic trait, but to what extent and how essential genes can become dispensable for viability remain unclear. Here, we investigate 'bypass of essentiality (BOE)' - an underexplored type of digenic genetic interaction that renders essential genes dispensable. Through analyzing essential genes on one of the six chromosome arms of the fission yeast Schizosaccharomyces pombe, we find that, remarkably, as many as 27% of them can be converted to non-essential genes by BOE interactions. Using this dataset we identify three principles of essentiality bypass: bypassable essential genes tend to have lower importance, tend to exhibit differential essentiality between species, and tend to act with other bypassable genes. In addition, we delineate mechanisms underlying bypassable essentiality, including the previously unappreciated mechanism of dormant redundancy between paralogs. The new insights gained on bypassable essentiality deepen our understanding of genotype-phenotype relationships and will facilitate drug development related to essential genes.
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25
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Makhoul C, Gosavi P, Duffield R, Delbridge B, Williamson NA, Gleeson PA. Intersectin-1 interacts with the golgin GCC88 to couple the actin network and Golgi architecture. Mol Biol Cell 2019; 30:370-386. [PMID: 30540523 PMCID: PMC6589577 DOI: 10.1091/mbc.e18-05-0313] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/19/2018] [Accepted: 12/04/2018] [Indexed: 12/19/2022] Open
Abstract
The maintenance of the Golgi ribbon relies on a dynamic balance between the actin and microtubule networks; however, the pathways controlling actin networks remain poorly defined. Previously, we showed that the trans-Golgi network (TGN) membrane tether/golgin, GCC88, modulates the Golgi ribbon architecture. Here, we show that dispersal of the Golgi ribbon by GCC88 is dependent on actin and the involvement of nonmuscle myosin IIA. We have identified the long isoform of intersectin-1 (ITSN-1), a guanine nucleotide exchange factor for Cdc42, as a novel Golgi component and an interaction partner of GCC88 responsible for mediating the actin-dependent dispersal of the Golgi ribbon. We show that perturbation of Golgi morphology by changes in membrane flux, mediated by silencing the retromer subunit Vps26, or in a model of neurodegeneration, induced by Tau overexpression, are also dependent on the ITSN-1-GCC88 interaction. Overall, our study reveals a role for a TGN golgin and ITSN-1 in linking to the actin cytoskeleton and regulating the balance between a compact Golgi ribbon and a dispersed Golgi, a pathway with relevance to pathophysiological conditions.
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Affiliation(s)
- Christian Makhoul
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Prajakta Gosavi
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Regina Duffield
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Bronwen Delbridge
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Nicholas A. Williamson
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A. Gleeson
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
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26
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Nutrient Signaling via the TORC1-Greatwall-PP2A B55δ Pathway Is Responsible for the High Initial Rates of Alcoholic Fermentation in Sake Yeast Strains of Saccharomyces cerevisiae. Appl Environ Microbiol 2018; 85:AEM.02083-18. [PMID: 30341081 DOI: 10.1128/aem.02083-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 10/13/2018] [Indexed: 01/14/2023] Open
Abstract
Saccharomyces cerevisiae sake yeast strain Kyokai no. 7 (K7) and its relatives carry a homozygous loss-of-function mutation in the RIM15 gene, which encodes a Greatwall family protein kinase. Disruption of RIM15 in nonsake yeast strains leads to improved alcoholic fermentation, indicating that the defect in Rim15p is associated with the enhanced fermentation performance of sake yeast cells. In order to understand how Rim15p mediates fermentation control, we here focused on target-of-rapamycin protein kinase complex 1 (TORC1) and protein phosphatase 2A with the B55δ regulatory subunit (PP2AB55δ), complexes that are known to act upstream and downstream of Rim15p, respectively. Several lines of evidence, including our previous transcriptomic analysis data, suggested enhanced TORC1 signaling in sake yeast cells during sake fermentation. Fermentation tests of the TORC1-related mutants using a laboratory strain revealed that TORC1 signaling positively regulates the initial fermentation rate in a Rim15p-dependent manner. Deletion of the CDC55 gene, encoding B55δ, abolished the high fermentation performance of Rim15p-deficient laboratory yeast and sake yeast cells, indicating that PP2AB55δ mediates the fermentation control by TORC1 and Rim15p. The TORC1-Greatwall-PP2AB55δ pathway similarly affected the fermentation rate in the fission yeast Schizosaccharomyces pombe, strongly suggesting that the evolutionarily conserved pathway governs alcoholic fermentation in yeasts. It is likely that elevated PP2AB55δ activity accounts for the high fermentation performance of sake yeast cells. Heterozygous loss-of-function mutations in CDC55 found in K7-related sake strains may indicate that the Rim15p-deficient phenotypes are disadvantageous to cell survival.IMPORTANCE The biochemical processes and enzymes responsible for glycolysis and alcoholic fermentation by the yeast S. cerevisiae have long been the subject of scientific research. Nevertheless, the factors determining fermentation performance in vivo are not fully understood. As a result, the industrial breeding of yeast strains has required empirical characterization of fermentation by screening numerous mutants through laborious fermentation tests. To establish a rational and efficient breeding strategy, key regulators of alcoholic fermentation need to be identified. In the present study, we focused on how sake yeast strains of S. cerevisiae have acquired high alcoholic fermentation performance. Our findings provide a rational molecular basis to design yeast strains with optimal fermentation performance for production of alcoholic beverages and bioethanol. In addition, as the evolutionarily conserved TORC1-Greatwall-PP2AB55δ pathway plays a major role in the glycolytic control, our work may contribute to research on carbohydrate metabolism in higher eukaryotes.
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Rajala A, Wang Y, Rajala RVS. Constitutive Activation Mutant mTOR Promote Cone Survival in Retinitis Pigmentosa Mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1074:491-497. [PMID: 29721981 DOI: 10.1007/978-3-319-75402-4_61] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Studies form our laboratory and others show that the oncogenic tyrosine kinase and serine threonine kinase signaling pathways are essential for cone photoreceptor survival. These pathways are downregulated in mouse models of retinal degenerative diseases. In the present study, we found that activation mutants of mTOR delayed the death of cones in a mouse model of retinal degeneration. These studies suggest that oncogenic protein kinases may be useful as therapeutic agents to treat retinal degenerations that affect cones.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Yuhong Wang
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Dean McGee Eye Institute, Oklahoma City, OK, USA.
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28
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Yang H, Jiang X, Li B, Yang HJ, Miller M, Yang A, Dhar A, Pavletich NP. Mechanisms of mTORC1 activation by RHEB and inhibition by PRAS40. Nature 2017; 552:368-373. [PMID: 29236692 PMCID: PMC5750076 DOI: 10.1038/nature25023] [Citation(s) in RCA: 378] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/08/2017] [Indexed: 12/13/2022]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to nutrients, energy levels, and growth factors. It contains the atypical kinase mTOR and the RAPTOR subunit that binds to the Tor signalling sequence (TOS) motif of substrates and regulators. mTORC1 is activated by the small GTPase RHEB (Ras homologue enriched in brain) and inhibited by PRAS40. Here we present the 3.0 ångström cryo-electron microscopy structure of mTORC1 and the 3.4 ångström structure of activated RHEB-mTORC1. RHEB binds to mTOR distally from the kinase active site, yet causes a global conformational change that allosterically realigns active-site residues, accelerating catalysis. Cancer-associated hyperactivating mutations map to structural elements that maintain the inactive state, and we provide biochemical evidence that they mimic RHEB relieving auto-inhibition. We also present crystal structures of RAPTOR-TOS motif complexes that define the determinants of TOS recognition, of an mTOR FKBP12-rapamycin-binding (FRB) domain-substrate complex that establishes a second substrate-recruitment mechanism, and of a truncated mTOR-PRAS40 complex that reveals PRAS40 inhibits both substrate-recruitment sites. These findings help explain how mTORC1 selects its substrates, how its kinase activity is controlled, and how it is activated by cancer-associated mutations.
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Affiliation(s)
- Haijuan Yang
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Xiaolu Jiang
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Buren Li
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Hyo J Yang
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Meredith Miller
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Angela Yang
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Ankita Dhar
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Nikola P Pavletich
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
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29
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Chia KH, Fukuda T, Sofyantoro F, Matsuda T, Amai T, Shiozaki K. Ragulator and GATOR1 complexes promote fission yeast growth by attenuating TOR complex 1 through Rag GTPases. eLife 2017; 6:30880. [PMID: 29199950 PMCID: PMC5752196 DOI: 10.7554/elife.30880] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 12/02/2017] [Indexed: 12/18/2022] Open
Abstract
TOR complex 1 (TORC1) is an evolutionarily conserved protein kinase complex that promotes cellular macromolecular synthesis and suppresses autophagy. Amino-acid-induced activation of mammalian TORC1 is initiated by its recruitment to the RagA/B-RagC/D GTPase heterodimer, which is anchored to lysosomal membranes through the Ragulator complex. We have identified in the model organism Schizosaccharomyces pombe a Ragulator-like complex that tethers the Gtr1-Gtr2 Rag heterodimer to the membranes of vacuoles, the lysosome equivalent in yeasts. Unexpectedly, the Ragulator-Rag complex is not required for the vacuolar targeting of TORC1, but the complex plays a crucial role in attenuating TORC1 activity independently of the Tsc1-Tsc2 complex, a known negative regulator of TORC1 signaling. The GATOR1 complex, which functions as Gtr1 GAP, is essential for the TORC1 attenuation by the Ragulator-Rag complex, suggesting that Gtr1GDP-Gtr2 on vacuolar membranes moderates TORC1 signaling for optimal cellular response to nutrients.
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Affiliation(s)
- Kim Hou Chia
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan
| | - Tomoyuki Fukuda
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan.,Department of Cellular Physiology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Fajar Sofyantoro
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan.,Department of Animal Physiology, Faculty of Biology, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Takato Matsuda
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan
| | - Takamitsu Amai
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan
| | - Kazuhiro Shiozaki
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan.,Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, United States
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FLT3-ITD induces expression of Pim kinases through STAT5 to confer resistance to the PI3K/Akt pathway inhibitors on leukemic cells by enhancing the mTORC1/Mcl-1 pathway. Oncotarget 2017; 9:8870-8886. [PMID: 29507660 PMCID: PMC5823622 DOI: 10.18632/oncotarget.22926] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/15/2017] [Indexed: 12/20/2022] Open
Abstract
FLT3-ITD is the most frequent tyrosine kinase mutation in acute myeloid leukemia (AML) associated with poor prognosis. We previously reported that activation of STAT5 confers resistance to PI3K/Akt inhibitors on the FLT3-ITD-positive AML cell line MV4-11 and 32D cells driven by FLT3-ITD (32D/ITD) but not by FLT3 mutated in the tyrosine kinase domain (32D/TKD). Here, we report the involvement of Pim kinases expressed through STAT5 activation in acquisition of this resistance. The specific pan-Pim kinase inhibitor AZD1208 as well as PIM447 in combination with the PI3K inhibitor GDC-0941 or the Akt inhibitor MK-2206 cooperatively downregulated the mTORC1/4EBP1 pathway, formation of the eIF4E/eIF4G complex, and Mcl-1 expression leading to activation of Bak and Bax to induce caspase-dependent apoptosis synergistically in these cells. These cooperative effects were enhanced or inhibited by knock down of mTOR or expression of its activated mutant, respectively. Overexpression of Mcl-1 conferred the resistance on 32D/ITD cells to combined inhibition of the PI3K/Akt pathway and Pim kinases, while the Mcl-1-specific BH3 mimetic A-1210477 conquered the resistance of MV4-11 cells to GDC-0941. Furthermore, overexpression of Pim-1 in 32D/TKD enhanced the mTORC1/Mcl-1 pathway and partially protected it from the PI3K/Akt inhibitors or the FLT3 inhibitor gilteritinib to confer the resistance to PI3K/Akt inhibitors. Finally, AZD1208 and GDC-0941 cooperatively inhibited the mTORC1/Mcl-1 pathway and reduced viable cell numbers of primary AML cells from some FLT3-ITD positive cases. Thus, Pim kinases may protect the mTORC1/4EBP1/Mcl-1 pathway to confer the resistance to the PI3K/Akt inhibitors on FLT3-ITD cells and represent promising therapeutic targets.
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Evolutionary Conservation of the Components in the TOR Signaling Pathways. Biomolecules 2017; 7:biom7040077. [PMID: 29104218 PMCID: PMC5745459 DOI: 10.3390/biom7040077] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/26/2017] [Accepted: 10/27/2017] [Indexed: 01/08/2023] Open
Abstract
Target of rapamycin (TOR) is an evolutionarily conserved protein kinase that controls multiple cellular processes upon various intracellular and extracellular stimuli. Since its first discovery, extensive studies have been conducted both in yeast and animal species including humans. Those studies have revealed that TOR forms two structurally and physiologically distinct protein complexes; TOR complex 1 (TORC1) is ubiquitous among eukaryotes including animals, yeast, protozoa, and plants, while TOR complex 2 (TORC2) is conserved in diverse eukaryotic species other than plants. The studies have also identified two crucial regulators of mammalian TORC1 (mTORC1), Ras homolog enriched in brain (RHEB) and RAG GTPases. Of these, RAG regulates TORC1 in yeast as well and is conserved among eukaryotes with the green algae and land plants as apparent exceptions. RHEB is present in various eukaryotes but sporadically missing in multiple taxa. RHEB, in the budding yeast Saccharomyces cerevisiae, appears to be extremely divergent with concomitant loss of its function as a TORC1 regulator. In this review, we summarize the evolutionarily conserved functions of the key regulatory subunits of TORC1 and TORC2, namely RAPTOR, RICTOR, and SIN1. We also delve into the evolutionary conservation of RHEB and RAG and discuss the conserved roles of these GTPases in regulating TORC1.
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32
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Laboucarié T, Detilleux D, Rodriguez-Mias RA, Faux C, Romeo Y, Franz-Wachtel M, Krug K, Maček B, Villén J, Petersen J, Helmlinger D. TORC1 and TORC2 converge to regulate the SAGA co-activator in response to nutrient availability. EMBO Rep 2017; 18:2197-2218. [PMID: 29079657 DOI: 10.15252/embr.201744942] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/31/2017] [Accepted: 09/07/2017] [Indexed: 12/19/2022] Open
Abstract
Gene expression regulation is essential for cells to adapt to changes in their environment. Co-activator complexes have well-established roles in transcriptional regulation, but less is known about how they sense and respond to signaling cues. We have previously shown that, in fission yeast, one such co-activator, the SAGA complex, controls gene expression and the switch from proliferation to differentiation in response to nutrient availability. Here, using a combination of genetic, biochemical, and proteomic approaches, we show that SAGA responds to nutrients through the differential phosphorylation of its Taf12 component, downstream of both the TORC1 and TORC2 pathways. Taf12 phosphorylation increases early upon starvation and is controlled by the opposing activities of the PP2A phosphatase, which is activated by TORC1, and the TORC2-activated Gad8AKT kinase. Mutational analyses suggest that Taf12 phosphorylation prevents cells from committing to differentiation until starvation reaches a critical level. Overall, our work reveals that SAGA is a direct target of nutrient-sensing pathways and has uncovered a mechanism by which TORC1 and TORC2 converge to control gene expression and cell fate decisions.
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Affiliation(s)
| | | | | | - Céline Faux
- CRBM, CNRS, University of Montpellier, Montpellier, France
| | - Yves Romeo
- CRBM, CNRS, University of Montpellier, Montpellier, France
| | | | | | - Boris Maček
- Proteome Center Tübingen, Tuebingen, Germany
| | - Judit Villén
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Janni Petersen
- Flinders Centre for Innovation in Cancer, School of Medicine, Faculty of Health Science, Flinders University, Adelaide, SA, Australia
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Abstract
All organisms can respond to the availability of nutrients by regulating their metabolism, growth, and cell division. Central to the regulation of growth in response to nutrient availability is the target of rapamycin (TOR) signaling that is composed of two structurally distinct complexes: TOR complex 1 (TORC1) and TOR complex 2 (TORC2). The TOR genes were first identified in yeast as target of rapamycin, a natural product of a soil bacterium, which proved beneficial as an immunosuppressive and anticancer drug and is currently being tested for a handful of other pathological conditions including diabetes, neurodegeneration, and age-related diseases. Studies of the TOR pathway unraveled a complex growth-regulating network. TOR regulates nutrient uptake, transcription, protein synthesis and degradation, as well as metabolic pathways, in a coordinated manner that ensures that cells grow or cease growth in response to nutrient availability. The identification of specific signals and mechanisms that stimulate TOR signaling is an active and exciting field of research that has already identified nitrogen and amino acids as key regulators of TORC1 activity. The signals, as well as the cellular functions of TORC2, are far less well understood. Additional open questions in the field concern the relationships between TORC1 and TORC2, as well as the links with other nutrient-responsive pathways. Here I review the main features of TORC1 and TORC2, with a particular focus on yeasts as model organisms.
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34
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Palmieri M, Pal R, Nelvagal HR, Lotfi P, Stinnett GR, Seymour ML, Chaudhury A, Bajaj L, Bondar VV, Bremner L, Saleem U, Tse DY, Sanagasetti D, Wu SM, Neilson JR, Pereira FA, Pautler RG, Rodney GG, Cooper JD, Sardiello M. mTORC1-independent TFEB activation via Akt inhibition promotes cellular clearance in neurodegenerative storage diseases. Nat Commun 2017; 8:14338. [PMID: 28165011 PMCID: PMC5303831 DOI: 10.1038/ncomms14338] [Citation(s) in RCA: 302] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 12/19/2016] [Indexed: 12/31/2022] Open
Abstract
Neurodegenerative diseases characterized by aberrant accumulation of undigested cellular components represent unmet medical conditions for which the identification of actionable targets is urgently needed. Here we identify a pharmacologically actionable pathway that controls cellular clearance via Akt modulation of transcription factor EB (TFEB), a master regulator of lysosomal pathways. We show that Akt phosphorylates TFEB at Ser467 and represses TFEB nuclear translocation independently of mechanistic target of rapamycin complex 1 (mTORC1), a known TFEB inhibitor. The autophagy enhancer trehalose activates TFEB by diminishing Akt activity. Administration of trehalose to a mouse model of Batten disease, a prototypical neurodegenerative disease presenting with intralysosomal storage, enhances clearance of proteolipid aggregates, reduces neuropathology and prolongs survival of diseased mice. Pharmacological inhibition of Akt promotes cellular clearance in cells from patients with a variety of lysosomal diseases, thus suggesting broad applicability of this approach. These findings open new perspectives for the clinical translation of TFEB-mediated enhancement of cellular clearance in neurodegenerative storage diseases.
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Affiliation(s)
- Michela Palmieri
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
| | - Rituraj Pal
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Hemanth R. Nelvagal
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 9RT, UK
| | - Parisa Lotfi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
| | - Gary R. Stinnett
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Michelle L. Seymour
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Arindam Chaudhury
- Department of Molecular Physiology and Biophysics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Lakshya Bajaj
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
| | - Vitaliy V. Bondar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
| | - Laura Bremner
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 9RT, UK
| | - Usama Saleem
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 9RT, UK
| | - Dennis Y. Tse
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030, USA
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Deepthi Sanagasetti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
| | - Samuel M. Wu
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Joel R. Neilson
- Department of Molecular Physiology and Biophysics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Fred A. Pereira
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Robia G. Pautler
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - George G. Rodney
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Jonathan D. Cooper
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London SE5 9RT, UK
| | - Marco Sardiello
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
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Multiple crosstalk between TOR and the cell integrity MAPK signaling pathway in fission yeast. Sci Rep 2016; 6:37515. [PMID: 27876895 PMCID: PMC5120329 DOI: 10.1038/srep37515] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/28/2016] [Indexed: 02/07/2023] Open
Abstract
In eukaryotic cells, the highly conserved Target of Rapamycin (TOR) and the Mitogen Activated Protein Kinase (MAPK) signaling pathways elicit adaptive responses to extra- and intracellular conditions by regulating essential cellular functions. However, the nature of the functional relationships between both pathways is not fully understood. In the fission yeast Schizosaccharomyces pombe the cell integrity MAPK pathway (CIP) regulates morphogenesis, cell wall structure and ionic homeostasis. We show that the Rab GTPase Ryh1, a TORC2 complex activator, cross-activates the CIP and its core member, the MAPK Pmk1, by two distinct mechanisms. The first one involves TORC2 and its downstream effector, Akt ortholog Gad8, which together with TORC1 target Psk1 increase protein levels of the PKC ortholog Pck2 during cell wall stress or glucose starvation. Also, Ryh1 activates Pmk1 in a TORC2-independent fashion by prompting plasma membrane trafficking and stabilization of upstream activators of the MAPK cascade, including PDK ortholog Ksg1 or Rho1 GEF Rgf1. Besides, stress-activated Pmk1 cross-inhibits Ryh1 signaling by decreasing the GTPase activation cycle, and this ensures cell growth during alterations in phosphoinositide metabolism. Our results reveal a highly intricate cross-regulatory relationship between both pathways that warrants adequate cell adaptation and survival in response to environmental changes.
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36
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Chen YB, Xu J, Skanderup AJ, Dong Y, Brannon AR, Wang L, Won HH, Wang PI, Nanjangud GJ, Jungbluth AA, Li W, Ojeda V, Hakimi AA, Voss MH, Schultz N, Motzer RJ, Russo P, Cheng EH, Giancotti FG, Lee W, Berger MF, Tickoo SK, Reuter VE, Hsieh JJ. Molecular analysis of aggressive renal cell carcinoma with unclassified histology reveals distinct subsets. Nat Commun 2016; 7:13131. [PMID: 27713405 PMCID: PMC5059781 DOI: 10.1038/ncomms13131] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 09/05/2016] [Indexed: 12/12/2022] Open
Abstract
Renal cell carcinomas with unclassified histology (uRCC) constitute a significant portion of aggressive non-clear cell renal cell carcinomas that have no standard therapy. The oncogenic drivers in these tumours are unknown. Here we perform a molecular analysis of 62 high-grade primary uRCC, incorporating targeted cancer gene sequencing, RNA sequencing, single-nucleotide polymorphism array, fluorescence in situ hybridization, immunohistochemistry and cell-based assays. We identify recurrent somatic mutations in 29 genes, including NF2 (18%), SETD2 (18%), BAP1 (13%), KMT2C (10%) and MTOR (8%). Integrated analysis reveals a subset of 26% uRCC characterized by NF2 loss, dysregulated Hippo–YAP pathway and worse survival, whereas 21% uRCC with mutations of MTOR, TSC1, TSC2 or PTEN and hyperactive mTORC1 signalling are associated with better clinical outcome. FH deficiency (6%), chromatin/DNA damage regulator mutations (21%) and ALK translocation (2%) distinguish additional cases. Altogether, this study reveals distinct molecular subsets for 76% of our uRCC cohort, which could have diagnostic and therapeutic implications. A subset of renal cell carcinomas have uncertain histology and are aggressive in nature. Here, the authors examine this group of unclassified renal cancers using genomics techniques and identify further subclasses of the tumours that have differing prognoses.
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Affiliation(s)
- Ying-Bei Chen
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Jianing Xu
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Anders Jacobsen Skanderup
- Computational Biology Program, Sloan Kettering Institute for Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yiyu Dong
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - A Rose Brannon
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Lu Wang
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Helen H Won
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Patricia I Wang
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Gouri J Nanjangud
- Molecular Cytogenetics Laboratory, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Achim A Jungbluth
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Wei Li
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Virginia Ojeda
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - A Ari Hakimi
- Department of Surgery, Urology Service, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Martin H Voss
- Department of Medicine, Genitourinary Oncology Service, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Nikolaus Schultz
- Computational Biology Program, Sloan Kettering Institute for Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Robert J Motzer
- Department of Medicine, Genitourinary Oncology Service, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Paul Russo
- Department of Surgery, Urology Service, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Emily H Cheng
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Filippo G Giancotti
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - William Lee
- Computational Biology Program, Sloan Kettering Institute for Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.,Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Michael F Berger
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Satish K Tickoo
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Victor E Reuter
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - James J Hsieh
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Department of Medicine, Genitourinary Oncology Service, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Department of Medicine, Weill Cornell Medical College, 1300 York Ave, New York, New York 10065, USA
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Zining J, Lu X, Caiyun H, Yuan Y. Genetic polymorphisms of mTOR and cancer risk: a systematic review and updated meta-analysis. Oncotarget 2016; 7:57464-57480. [PMID: 27462867 PMCID: PMC5302868 DOI: 10.18632/oncotarget.10805] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/29/2016] [Indexed: 12/16/2022] Open
Abstract
mTOR regulates several cellular processes that are critical for tumorigenesis. However, previous studies on the association of mTOR polymorphisms with predisposition to different cancer types are somewhat contradictory. Therefore, we performed a systematic review and updated meta-analysis of the available evidence regarding the relationship between mTOR single nucleotide polymorphisms (SNPs) and cancer risk. Up to November 2015, 23 original publications were identified covering 20 mTOR SNPs, of which seven SNPs (rs2536, rs2295080, rs1883965, rs1034528, rs17036508, rs3806317 and rs1064261) were included in the final meta-analysis. We estimated the summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for mTOR polymorphisms and cancer risk, and used the model-free approach to investigate the biological effect of each polymorphism. Our meta-analysis found that rs1883965, rs1034528, and rs17036508 were correlated with increased cancer risk in the complete over-dominant model (rs1883965 GA versus GG/AA: fixed-effects OR=1.15, 95% CI 1.02-1.29; rs1034528 GC versus GG/CC: fixed-effects OR=1.30, 95% CI 1.13-1.48; rs17036508 TC versus CC/TT: fixed-effects OR=1.23, 95% CI 1.06-1.43). Stratifying analyses by cancer type, we found that the rs2295080 G allele was associated with a significantly higher risk of acute leukemia in the recessive model (GG versus GT/TT: fixed-effects OR=2.08, 95% CI 1.34-3.22) and a lower risk of genitourinary cancers in the dominant model (TG/GG versus TT: fixed-effects OR=0.77, 95% CI 0.68-0.86). Interestingly, further expression analysis showed that homozygous variant genotype carriers of rs1883965, rs1034528 and rs17036508 had lower mTOR transcript levels, based on HapMap data.
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Affiliation(s)
- Jin Zining
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, Key Laboratory of Cancer Etiology and Prevention of Liaoning Provincial Education Department, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xu Lu
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, Key Laboratory of Cancer Etiology and Prevention of Liaoning Provincial Education Department, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - He Caiyun
- Department of Molecular Diagnostics, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Yuan Yuan
- Tumor Etiology and Screening Department of Cancer Institute and General Surgery, Key Laboratory of Cancer Etiology and Prevention of Liaoning Provincial Education Department, The First Affiliated Hospital of China Medical University, Shenyang, China
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38
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Zhou H, Shang C, Wang M, Shen T, Kong L, Yu C, Ye Z, Luo Y, Liu L, Li Y, Huang S. Ciclopirox olamine inhibits mTORC1 signaling by activation of AMPK. Biochem Pharmacol 2016; 116:39-50. [PMID: 27396756 DOI: 10.1016/j.bcp.2016.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/06/2016] [Indexed: 01/22/2023]
Abstract
Ciclopirox olamine (CPX), an off-patent antifungal agent, has recently been identified as a potential anticancer agent. The mammalian target of rapamycin (mTOR) is a central controller of cell growth, proliferation and survival. Little is known about whether and how CPX executes its anticancer action by inhibiting mTOR. Here we show that CPX inhibited the phosphorylation of p70 S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1), two downstream effector molecules of mTOR complex 1 (mTORC1), in a spectrum of human tumor cells, indicating that CPX inhibits mTORC1 signaling. Using rhabdomyosarcoma cells as an experimental model, we found that expression of constitutively active mTOR (E2419K) conferred resistance to CPX inhibition of cell proliferation, suggesting that CPX inhibition of mTORC1 contributed to its anticancer effect. In line with this, treatment with CPX inhibited tumor growth and concurrently suppressed mTORC1 signaling in RD xenografts. Mechanistically, CPX inhibition of mTORC1 was neither via inhibition of IGF-I receptor or phosphoinositide 3-kinase (PI3K), nor by activation of phosphatase and tensin homolog (PTEN). Instead, CPX inhibition of mTORC1 was attributed to activation of AMP-activated protein kinase (AMPK)-tuberous sclerosis complexes (TSC)/raptor pathways. This is supported by the findings that CPX activated AMPK; inhibition of AMPK with Compound C or ectopic expression of dominant negative AMPKα partially prevented CPX from inhibiting mTORC1; silencing TSC2 attenuated CPX inhibition of mTORC1; and CPX also increased AMPK-mediated phosphorylation of raptor (S792). Therefore, the results indicate that CPX exerts the anticancer effect by activating AMPK, resulting in inhibition of mTORC1 signaling.
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Affiliation(s)
- Hongyu Zhou
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Chaowei Shang
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA; Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA
| | - Min Wang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Tao Shen
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA; Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA
| | - Lingmei Kong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Chunlei Yu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zhennan Ye
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Yan Luo
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA
| | - Lei Liu
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA
| | - Yan Li
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
| | - Shile Huang
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA; Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA.
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39
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Sato T, Ishii J, Ota Y, Sasaki E, Shibagaki Y, Hattori S. Mammalian target of rapamycin (mTOR) complex 2 regulates filamin A-dependent focal adhesion dynamics and cell migration. Genes Cells 2016; 21:579-93. [DOI: 10.1111/gtc.12366] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/01/2016] [Indexed: 12/23/2022]
Affiliation(s)
- Tatsuhiro Sato
- Division of Biochemistry; School of Pharmaceutical Sciences; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
| | - Junko Ishii
- Division of Biochemistry; School of Pharmaceutical Sciences; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
| | - Yuki Ota
- Division of Biochemistry; School of Pharmaceutical Sciences; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
| | - Eri Sasaki
- Division of Biochemistry; School of Pharmaceutical Sciences; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
| | - Yoshio Shibagaki
- Division of Biochemistry; School of Pharmaceutical Sciences; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
| | - Seisuke Hattori
- Division of Biochemistry; School of Pharmaceutical Sciences; Kitasato University; 5-9-1 Shirokane Minato-ku Tokyo 108-8641 Japan
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40
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Correia-Melo C, Marques FDM, Anderson R, Hewitt G, Hewitt R, Cole J, Carroll BM, Miwa S, Birch J, Merz A, Rushton MD, Charles M, Jurk D, Tait SWG, Czapiewski R, Greaves L, Nelson G, Bohlooly-Y M, Rodriguez-Cuenca S, Vidal-Puig A, Mann D, Saretzki G, Quarato G, Green DR, Adams PD, von Zglinicki T, Korolchuk VI, Passos JF. Mitochondria are required for pro-ageing features of the senescent phenotype. EMBO J 2016; 35:724-42. [PMID: 26848154 PMCID: PMC4818766 DOI: 10.15252/embj.201592862] [Citation(s) in RCA: 545] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 01/12/2016] [Indexed: 01/07/2023] Open
Abstract
Cell senescence is an important tumour suppressor mechanism and driver of ageing. Both functions are dependent on the development of the senescent phenotype, which involves an overproduction of pro‐inflammatory and pro‐oxidant signals. However, the exact mechanisms regulating these phenotypes remain poorly understood. Here, we show the critical role of mitochondria in cellular senescence. In multiple models of senescence, absence of mitochondria reduced a spectrum of senescence effectors and phenotypes while preserving ATP production via enhanced glycolysis. Global transcriptomic analysis by RNA sequencing revealed that a vast number of senescent‐associated changes are dependent on mitochondria, particularly the pro‐inflammatory phenotype. Mechanistically, we show that the ATM, Akt and mTORC1 phosphorylation cascade integrates signals from the DNA damage response (DDR) towards PGC‐1β‐dependent mitochondrial biogenesis, contributing to a ROS‐mediated activation of the DDR and cell cycle arrest. Finally, we demonstrate that the reduction in mitochondrial content in vivo, by either mTORC1 inhibition or PGC‐1β deletion, prevents senescence in the ageing mouse liver. Our results suggest that mitochondria are a candidate target for interventions to reduce the deleterious impact of senescence in ageing tissues.
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Affiliation(s)
- Clara Correia-Melo
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK GABBA Program, Abel Salazar Biomedical Sciences Institute University of Porto, Porto, Portugal
| | - Francisco D M Marques
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Rhys Anderson
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Graeme Hewitt
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Rachael Hewitt
- Institute of Cancer Sciences, CR-UK Beatson Institute, University of Glasgow, Glasgow, UK
| | - John Cole
- Institute of Cancer Sciences, CR-UK Beatson Institute, University of Glasgow, Glasgow, UK
| | - Bernadette M Carroll
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Satomi Miwa
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Jodie Birch
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Alina Merz
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Michael D Rushton
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Michelle Charles
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Diana Jurk
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Stephen W G Tait
- Institute of Cancer Sciences, CR-UK Beatson Institute, University of Glasgow, Glasgow, UK
| | - Rafal Czapiewski
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Laura Greaves
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University Centre for Brain Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK
| | - Glyn Nelson
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | | | - Sergio Rodriguez-Cuenca
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Antonio Vidal-Puig
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Derek Mann
- Faculty of Medical Sciences, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Gabriele Saretzki
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Giovanni Quarato
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Peter D Adams
- Institute of Cancer Sciences, CR-UK Beatson Institute, University of Glasgow, Glasgow, UK
| | - Thomas von Zglinicki
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - Viktor I Korolchuk
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - João F Passos
- Institute for Cell and Molecular Biosciences, Campus for Ageing and Vitality, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
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Carroll B, Maetzel D, Maddocks ODK, Otten G, Ratcliff M, Smith GR, Dunlop EA, Passos JF, Davies OR, Jaenisch R, Tee AR, Sarkar S, Korolchuk VI. Control of TSC2-Rheb signaling axis by arginine regulates mTORC1 activity. eLife 2016; 5:e11058. [PMID: 26742086 PMCID: PMC4764560 DOI: 10.7554/elife.11058] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/30/2015] [Indexed: 01/07/2023] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) is the key signaling hub that regulates cellular protein homeostasis, growth, and proliferation in health and disease. As a prerequisite for activation of mTORC1 by hormones and mitogens, there first has to be an available pool of intracellular amino acids. Arginine, an amino acid essential during mammalian embryogenesis and early development is one of the key activators of mTORC1. Herein, we demonstrate that arginine acts independently of its metabolism to allow maximal activation of mTORC1 by growth factors via a mechanism that does not involve regulation of mTORC1 localization to lysosomes. Instead, arginine specifically suppresses lysosomal localization of the TSC complex and interaction with its target small GTPase protein, Rheb. By interfering with TSC-Rheb complex, arginine relieves allosteric inhibition of Rheb by TSC. Arginine cooperates with growth factor signaling which further promotes dissociation of TSC2 from lysosomes and activation of mTORC1. Arginine is the main amino acid sensed by the mTORC1 pathway in several cell types including human embryonic stem cells (hESCs). Dependence on arginine is maintained once hESCs are differentiated to fibroblasts, neurons, and hepatocytes, highlighting the fundamental importance of arginine-sensing to mTORC1 signaling. Together, our data provide evidence that different growth promoting cues cooperate to a greater extent than previously recognized to achieve tight spatial and temporal regulation of mTORC1 signaling.
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Affiliation(s)
- Bernadette Carroll
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Dorothea Maetzel
- Whitehead Institute for Biomedical ResearchMassachusetts Institute of TechnologyCambridgeUnited States
| | | | - Gisela Otten
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Matthew Ratcliff
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Graham R Smith
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Elaine A Dunlop
- Institute of Cancer and GeneticsCardiff UniversityCardiffUnited Kingdom
| | - João F Passos
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Owen R Davies
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical ResearchMassachusetts Institute of TechnologyCambridgeUnited States
| | - Andrew R Tee
- Institute of Cancer and GeneticsCardiff UniversityCardiffUnited Kingdom
| | - Sovan Sarkar
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Viktor I Korolchuk
- Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
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42
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Cai H, Jiang D, Qi F, Xu J, Yu L, Xiao Q. HRP-3 protects the hepatoma cells from glucose deprivation-induced apoptosis. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:14383-14391. [PMID: 26823754 PMCID: PMC4713540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 10/22/2015] [Indexed: 06/05/2023]
Abstract
UNLABELLED Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. It is important for HCC cells to resist to apoptosis caused by adverse energy pressure in microenvironment during the HCC tumorigenesis. HRP-3, a member of hepatoma-derived growth factor (HDGF)-related proteins (HRP) family, was shown to be highly up-regulated in HCC tissues and play an important role in HCC pathogenesis based on our previous research. The aim of the study was to investigate the HRP-3's role in HCC cells endurance against energy pressure. METHOD The HRP-3 expression level in primary rat hepatocytes and human HCC cell lines were examined when changing the extracellular glucose concentration. To assess biological function of HRP-3 during glucose deprivation, HRP-3 stable knockdown and control clones of SMMC-7721 and SK-hep1 were constructed for further analysis including cellular morphology observation, apoptotic sub G1 peak analysis and the mTOR-mediated phosphorylation of S6K1 detection in the absence of glucose. RESULTS Expression level of HRP-3 protein was highly up-regulated both in primary rat hepatocytes and HCC cells as prolonging the stimulation of glucose deprivation. Both morphology and sub-G1 phase analyses indicated that stable knockdown of HRP-3 sensitized HCC cells to glucose deprivation-induced cell apoptosis. Furthermore, silence of HRP-3 prevented the de-phosphorylation of S6K1 induced by glucose deprivation, which was an essential molecular event for HCC cell survival in energy pressure. CONCLUSIONS We propose that glucose deprivation-induced HRP-3 up-regulation potentially plays a major role in protecting HCC cells against apoptosis caused by energy pressure.
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Affiliation(s)
- Hao Cai
- The State Key Laboratory of Genetics Engineering, School of Life Science, Fudan UniversityShanghai 200438, P. R. China
| | - Deke Jiang
- The State Key Laboratory of Genetics Engineering, School of Life Science, Fudan UniversityShanghai 200438, P. R. China
- Center for Genomic Transformational Medicine and Prevention, School of Public Health, Fudan UniversityShanghai 200032, P. R. China
| | - Fang Qi
- The Second Department of Surgery, Hospital of China No. 17 Metallurgical Construction CorpMaanshan 243000, Anhui, P. R. China
| | - Jianfeng Xu
- Center for Genomic Transformational Medicine and Prevention, School of Public Health, Fudan UniversityShanghai 200032, P. R. China
| | - Long Yu
- The State Key Laboratory of Genetics Engineering, School of Life Science, Fudan UniversityShanghai 200438, P. R. China
| | - Qianyi Xiao
- Center for Genomic Transformational Medicine and Prevention, School of Public Health, Fudan UniversityShanghai 200032, P. R. China
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43
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Yamaguchi H, Kawazu M, Yasuda T, Soda M, Ueno T, Kojima S, Yashiro M, Yoshino I, Ishikawa Y, Sai E, Mano H. Transforming somatic mutations of mammalian target of rapamycin kinase in human cancer. Cancer Sci 2015; 106:1687-92. [PMID: 26432419 PMCID: PMC4714661 DOI: 10.1111/cas.12828] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 09/24/2015] [Accepted: 09/26/2015] [Indexed: 02/06/2023] Open
Abstract
Mammalian target of rapamycin (mTOR) is a serine–threonine kinase that acts downstream of the phosphatidylinositol 3‐kinase signaling pathway and regulates a wide range of cellular functions including transcription, translation, proliferation, apoptosis, and autophagy. Whereas genetic alterations that result in mTOR activation are frequently present in human cancers, whether the mTOR gene itself becomes an oncogene through somatic mutation has remained unclear. We have now identified a somatic non‐synonymous mutation of mTOR that results in a leucine‐to‐valine substitution at amino acid position 2209 in a specimen of large cell neuroendocrine carcinoma. The mTOR(L2209V) mutant manifested marked transforming potential in a focus formation assay with mouse 3T3 fibroblasts, and it induced the phosphorylation of p70 S6 kinase, S6 ribosomal protein, and eukaryotic translation initiation factor 4E–binding protein 1 in these cells. Examination of additional tumor specimens as well as public and in‐house databases of cancer genome mutations identified another 28 independent non‐synonymous mutations of mTOR in various cancer types, with 12 of these mutations also showing transforming ability. Most of these oncogenic mutations cluster at the interface between the kinase domain and the FAT (FRAP, ATM, TRRAP) domain in the 3‐D structure of mTOR. Transforming mTOR mutants were also found to promote 3T3 cell survival, and their oncogenic activity was sensitive to rapamycin. Our data thus show that mTOR acquires transforming activity through genetic changes in cancer, and they suggest that such tumors may be candidates for molecularly targeted therapy with mTOR inhibitors.
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Affiliation(s)
- Hiroyuki Yamaguchi
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Second Department of Internal Medicine, Nagasaki University Hospital, Nagasaki, Japan
| | - Masahito Kawazu
- Department of Medical Genomics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Takahiko Yasuda
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Manabu Soda
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Toshihide Ueno
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shinya Kojima
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masakazu Yashiro
- Department of Surgical Oncology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Ichiro Yoshino
- Department of General Thoracic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yuichi Ishikawa
- Department of Pathology, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Eirin Sai
- Department of Medical Genomics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Mano
- Department of Cellular Signaling, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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44
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Liu Q, Ma Y, Zhou X, Furuyashiki T. Constitutive Tor2 Activity Promotes Retention of the Amino Acid Transporter Agp3 at Trans-Golgi/Endosomes in Fission Yeast. PLoS One 2015; 10:e0139045. [PMID: 26447710 PMCID: PMC4598100 DOI: 10.1371/journal.pone.0139045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/07/2015] [Indexed: 12/13/2022] Open
Abstract
Amino acid transporters are located at specific subcellular compartments, and their localizations are regulated by the extracellular availability of amino acids. In yeast, target of rapamycin (TOR) activation induces the internalization of amino acid transporters located at the plasma membrane. However, whether and how TOR signaling regulates other amino acid transporters located at intracellular compartments remains unknown. Here, we demonstrate that in the fission yeast, the TOR inhibitor Torin-1 induces the transfer of several yellow fluorescent protein (YFP)-fused intracellular amino acid transporters, including Agp3, Isp5, Aat1, and Put4, from trans-Golgi/endosomes into the vacuoles. By contrast, the localizations of YFP-fused Can1, Fnx1, and Fnx2 transporter proteins were unaffected upon Torin-1 treatment. There are two TOR isoforms in fission yeast, Tor1 and Tor2. Whereas tor1 deletion did not affect the Torin-1-induced transfer of Agp3-YFP, Tor2 inhibition using a temperature-sensitive mutant induced the transfer of Agp3-YFP to the vacuolar lumen, similar to the effects of Torin-1 treatment. Tor2 inhibition also induced the transfer of the YFP-fused Isp5, Aat1, and Put4 transporter proteins to the vacuoles, although only partial transfer of the latter two transporters was observed. Under nitrogen depletion accompanied by reduced Tor2 activity, Agp3-YFP was transferred from the trans-Golgi/endosomes to the plasma membrane and then to the vacuoles, where it was degraded by the vacuolar proteases Isp6 and Psp3. Mutants with constitutively active Tor2 showed delayed transfer of Agp3-YFP to the plasma membrane upon nitrogen depletion. Cells lacking Tsc2, a negative regulator of Tor2, also showed a delay in this process in a Tor2-dependent manner. Taken together, these findings suggest that constitutive Tor2 activity is critical for the retention of amino acid transporters at trans-Golgi/endosomes. Moreover, nitrogen depletion suppresses Tor2 activity through Tsc2, thereby promoting the surface expression of these transporters.
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Affiliation(s)
- Qingbin Liu
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yan Ma
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
- * E-mail:
| | - Xin Zhou
- Department of Oncology, the First Affiliated Hospital of Liaoning Medical University, Jinzhou, China
| | - Tomoyuki Furuyashiki
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
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45
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TORC1 Regulates Developmental Responses to Nitrogen Stress via Regulation of the GATA Transcription Factor Gaf1. mBio 2015; 6:e00959. [PMID: 26152587 PMCID: PMC4488950 DOI: 10.1128/mbio.00959-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The TOR (target of rapamycin [sirolimus]) is a universally conserved kinase that couples nutrient availability to cell growth. TOR complex 1 (TORC1) in Schizosaccharomyces pombe positively regulates growth in response to nitrogen availability while suppressing cellular responses to nitrogen stress. Here we report the identification of the GATA transcription factor Gaf1 as a positive regulator of the nitrogen stress-induced gene isp7+, via three canonical GATA motifs. We show that under nitrogen-rich conditions, TORC1 positively regulates the phosphorylation and cytoplasmic retention of Gaf1 via the PP2A-like phosphatase Ppe1. Under nitrogen stress conditions when TORC1 is inactivated, Gaf1 becomes dephosphorylated and enters the nucleus. Gaf1 was recently shown to negatively regulate the transcription induction of ste11+, a major regulator of sexual development. Our findings support a model of a two-faceted role of Gaf1 during nitrogen stress. Gaf1 positively regulates genes that are induced early in the response to nitrogen stress, while inhibiting later responses, such as sexual development. Taking these results together, we identify Gaf1 as a novel target for TORC1 signaling and a step-like mechanism to modulate the nitrogen stress response. TOR complex 1 (TORC1) is an evolutionary conserved protein complex that positively regulates growth and proliferation, while inhibiting starvation responses. In fission yeast, the activity of TORC1 is downregulated in response to nitrogen starvation, and cells reprogram their transcriptional profile and prepare for sexual development. We identify Gaf1, a GATA-like transcription factor that regulates transcription and sexual development in response to starvation, as a downstream target for TORC1 signaling. Under nitrogen-rich conditions, TORC1 positively regulates the phosphorylation and cytoplasmic retention of Gaf1 via the PP2A-like phosphatase Ppe1. Under nitrogen stress conditions when TORC1 is inactivated, Gaf1 becomes dephosphorylated and enters the nucleus. Budding yeast TORC1 regulates GATA transcription factors via the phosphatase Sit4, a structural homologue of Ppe1. Thus, the TORC1-GATA transcription module appears to be conserved in evolution and may also be found in higher eukaryotes.
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Nakashima M, Saitsu H, Takei N, Tohyama J, Kato M, Kitaura H, Shiina M, Shirozu H, Masuda H, Watanabe K, Ohba C, Tsurusaki Y, Miyake N, Zheng Y, Sato T, Takebayashi H, Ogata K, Kameyama S, Kakita A, Matsumoto N. Somatic Mutations in the MTOR gene cause focal cortical dysplasia type IIb. Ann Neurol 2015; 78:375-86. [PMID: 26018084 DOI: 10.1002/ana.24444] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 05/26/2015] [Accepted: 05/26/2015] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Focal cortical dysplasia (FCD) type IIb is a cortical malformation characterized by cortical architectural abnormalities, dysmorphic neurons, and balloon cells. It has been suggested that FCDs are caused by somatic mutations in cells in the developing brain. Here, we explore the possible involvement of somatic mutations in FCD type IIb. METHODS We collected a total of 24 blood-brain paired samples with FCD, including 13 individuals with FCD type IIb, 5 with type IIa, and 6 with type I. We performed whole-exome sequencing using paired samples from 9 of the FCD type IIb subjects. Somatic MTOR mutations were identified and further investigated using all 24 paired samples by deep sequencing of the entire gene's coding region. Somatic MTOR mutations were confirmed by droplet digital polymerase chain reaction. The effect of MTOR mutations on mammalian target of rapamycin (mTOR) kinase signaling was evaluated by immunohistochemistry and Western blotting analyses of brain samples and by in vitro transfection experiments. RESULTS We identified four lesion-specific somatic MTOR mutations in 6 of 13 (46%) individuals with FCD type IIb showing mutant allele rates of 1.11% to 9.31%. Functional analyses showed that phosphorylation of ribosomal protein S6 in FCD type IIb brain tissues with MTOR mutations was clearly elevated, compared to control samples. Transfection of any of the four MTOR mutants into HEK293T cells led to elevated phosphorylation of 4EBP, the direct target of mTOR kinase. INTERPRETATION We found low-prevalence somatic mutations in MTOR in FCD type IIb, indicating that activating somatic mutations in MTOR cause FCD type IIb.
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Affiliation(s)
- Mitsuko Nakashima
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Nobuyuki Takei
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Jun Tohyama
- Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Niigata, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Hiroki Kitaura
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Masaaki Shiina
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hiroshi Shirozu
- Department of Functional Neurosurgery, Epilepsy Center, Nishi-Niigata Chuo National Hospital, Niigata, Japan
| | - Hiroshi Masuda
- Department of Functional Neurosurgery, Epilepsy Center, Nishi-Niigata Chuo National Hospital, Niigata, Japan
| | - Keisuke Watanabe
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Chihiro Ohba
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yoshinori Tsurusaki
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yingjun Zheng
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Tatsuhiro Sato
- Division of Biochemistry, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Kazuhiro Ogata
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Shigeki Kameyama
- Department of Functional Neurosurgery, Epilepsy Center, Nishi-Niigata Chuo National Hospital, Niigata, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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Chantranupong L, Wolfson RL, Sabatini DM. Nutrient-sensing mechanisms across evolution. Cell 2015; 161:67-83. [PMID: 25815986 DOI: 10.1016/j.cell.2015.02.041] [Citation(s) in RCA: 242] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Indexed: 12/11/2022]
Abstract
For organisms to coordinate their growth and development with nutrient availability, they must be able to sense nutrient levels in their environment. Here, we review select nutrient-sensing mechanisms in a few diverse organisms. We discuss how these mechanisms reflect the nutrient requirements of specific species and how they have adapted to the emergence of multicellularity in eukaryotes.
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Affiliation(s)
- Lynne Chantranupong
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Rachel L Wolfson
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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Li N, Sui J, Liu H, Zhong M, Zhang M, Wang Y, Hao F. Expression of phosphorylated Akt/mTOR and clinical significance in human ameloblastoma. Int J Clin Exp Med 2015; 8:5236-5244. [PMID: 26131097 PMCID: PMC4483961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/30/2015] [Indexed: 06/04/2023]
Abstract
This study aimed to evaluate the expression of AKT and phosphorylated AKT (p-Akt) in human ameloblastoma (AB). Immunohistochemistry showed human AB was positive for Akt and Akt expression was mainly found in the cytoplasm of epithelial cells. The Akt expression in AB was significantly higher than that in normal oral mucosa (NOM), but still lower than that in oral squamous cell carcinoma (OSCC). NOM was negative for p-Akt, but AB was positive for p-Akt. In some AB tissues, p-Akt expression was found in both cytoplasm and nucleus. Akt expression in AB was significantly different from that in NOM and OSCC. The p-Akt in AB was markedly higher than that in NOM, but lower than that in OSCC. mTOR expressed in cytoplasm in AB, but not in NOM. P-mTOR expressed on cell membrane in NOM, while in cytoplasm and nucleus in Ab. Results of western blot assay showed that Akt expression was found in all the AB tissues, and increased in tissues with malignant transformation. In addition, the p-Akt expression also markedly increased in AB, but was still lower than that in OSCC tissues. Compared to NOM, mTOR and p-mTOR expression significantly increased in AB. BandScan 5.0 software was used to detect the optical density of protein bands. Results showed p-Akt, mTOR and p-mTOR expression in AB was markedly different from that in control group.
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Affiliation(s)
- Ning Li
- Department of Stomatology, Stomatological Hospital of China Medical UniversityShenyang, China
- Department of Stomatology, 202# Hospital of PLAShenyang, China
| | - Jianfu Sui
- Department of Stomatology, 202# Hospital of PLAShenyang, China
| | - Hao Liu
- Department of Stomatology, Stomatological Hospital of China Medical UniversityShenyang, China
| | - Ming Zhong
- Department of Stomatology, Stomatological Hospital of China Medical UniversityShenyang, China
| | - Min Zhang
- Department of Stomatology, Stomatological Hospital of China Medical UniversityShenyang, China
| | - Yan Wang
- Department of Stomatology, Stomatological Hospital of China Medical UniversityShenyang, China
| | - Fengyu Hao
- Department of Stomatology, Stomatological Hospital of China Medical UniversityShenyang, China
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Lim JS, Kim WI, Kang HC, Kim SH, Park AH, Park EK, Cho YW, Kim S, Kim HM, Kim JA, Kim J, Rhee H, Kang SG, Kim HD, Kim D, Kim DS, Lee JH. Brain somatic mutations in MTOR cause focal cortical dysplasia type II leading to intractable epilepsy. Nat Med 2015; 21:395-400. [PMID: 25799227 DOI: 10.1038/nm.3824] [Citation(s) in RCA: 378] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/12/2015] [Indexed: 12/18/2022]
Abstract
Focal cortical dysplasia type II (FCDII) is a sporadic developmental malformation of the cerebral cortex characterized by dysmorphic neurons, dyslamination and medically refractory epilepsy. It has been hypothesized that FCD is caused by somatic mutations in affected regions. Here, we used deep whole-exome sequencing (read depth, 412-668×) validated by site-specific amplicon sequencing (100-347,499×) in paired brain-blood DNA from four subjects with FCDII and uncovered a de novo brain somatic mutation, mechanistic target of rapamycin (MTOR) c.7280T>C (p.Leu2427Pro) in two subjects. Deep sequencing of the MTOR gene in an additional 73 subjects with FCDII using hybrid capture and PCR amplicon sequencing identified eight different somatic missense mutations found in multiple brain tissue samples of ten subjects. The identified mutations accounted for 15.6% of all subjects with FCDII studied (12 of 77). The identified mutations induced the hyperactivation of mTOR kinase. Focal cortical expression of mutant MTOR by in utero electroporation in mice was sufficient to disrupt neuronal migration and cause spontaneous seizures and cytomegalic neurons. Inhibition of mTOR with rapamycin suppressed cytomegalic neurons and epileptic seizures. This study provides, to our knowledge, the first evidence that brain somatic activating mutations in MTOR cause FCD and identifies mTOR as a treatment target for intractable epilepsy in FCD.
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Affiliation(s)
- Jae Seok Lim
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, Korea
| | - Woo-il Kim
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, Korea
| | - Hoon-Chul Kang
- 1] Division of Pediatric Neurology, Department of Pediatrics, Pediatric Epilepsy Clinics, Severance Children's Hospital, Seoul, Korea. [2] Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Se Hoon Kim
- Department of Pathology, Brain Korea 21 project for medical science, Yonsei University College of Medicine, Seoul, Korea
| | - Ah Hyung Park
- Department of Biological Sciences, KAIST, Daejeon, Korea
| | - Eun Kyung Park
- 1] Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea. [2] Department of Neurosurgery, Pediatric Epilepsy Clinics, Brain Korea 21 project for medical science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Young-Wook Cho
- Korea Basic Science Institute, Chuncheon Center, Chuncheon-si, Gangwon-do, Korea
| | - Sangwoo Kim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Ho Min Kim
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, Korea
| | - Jeong A Kim
- 1] Division of Pediatric Neurology, Department of Pediatrics, Pediatric Epilepsy Clinics, Severance Children's Hospital, Seoul, Korea. [2] Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Junho Kim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Hwanseok Rhee
- Macrogen Bioinformatics Center, Macrogen, Gasan-dong, Geumcheon-gu, Seoul, Korea
| | - Seok-Gu Kang
- 1] Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea. [2] Department of Neurosurgery, Pediatric Epilepsy Clinics, Brain Korea 21 project for medical science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Heung Dong Kim
- 1] Division of Pediatric Neurology, Department of Pediatrics, Pediatric Epilepsy Clinics, Severance Children's Hospital, Seoul, Korea. [2] Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Daesoo Kim
- Department of Biological Sciences, KAIST, Daejeon, Korea
| | - Dong-Seok Kim
- 1] Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea. [2] Department of Neurosurgery, Pediatric Epilepsy Clinics, Brain Korea 21 project for medical science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Jeong Ho Lee
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, Korea
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Davie E, Forte GMA, Petersen J. Nitrogen regulates AMPK to control TORC1 signaling. Curr Biol 2015; 25:445-54. [PMID: 25639242 PMCID: PMC4331286 DOI: 10.1016/j.cub.2014.12.034] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 11/06/2014] [Accepted: 12/10/2014] [Indexed: 10/29/2022]
Abstract
BACKGROUND Cell growth and cell-cycle progression are tightly coordinated to enable cells to adjust their size (timing of division) to the demands of proliferation in varying nutritional environments. In fission yeast, nitrogen stress results in sustained proliferation at a reduced size. RESULTS Here, we show that cells can sense nitrogen stress to reduce target of rapamycin complex-1 (TORC1) activity. Nitrogen-stress-induced TORC1 inhibition differs from amino-acid-dependent control of TORC1 and requires the Ssp2 (AMPKα) kinase, the Tsc1/2 complex, and Rhb1 GTPase. Importantly, the β and γ regulatory subunits of AMPK are not required to control cell division in response to nitrogen stress, providing evidence for a nitrogen-sensing mechanism that is independent of changes in intracellular ATP/AMP levels. The CaMKK homolog Ssp1 is constitutively required for phosphorylation of the AMPKα(Ssp2) T loop. However, we find that a second homolog CaMKK(Ppk34) is specifically required to stimulate AMPKα(Ssp2) activation in response to nitrogen stress. Finally, ammonia also controls mTORC1 activity in human cells; mTORC1 is activated upon the addition of ammonium to glutamine-starved Hep3B cancer cells. CONCLUSIONS The alternative nitrogen source ammonia can simulate TORC1 activity to support growth and division under challenging nutrient settings, a situation often seen in cancer.
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Affiliation(s)
- Elizabeth Davie
- Faculty of Life Sciences, University of Manchester, C.4255 Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Gabriella M A Forte
- Faculty of Life Sciences, University of Manchester, C.4255 Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Janni Petersen
- Faculty of Life Sciences, University of Manchester, C.4255 Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; Flinders Centre for Innovation in Cancer, School of Medicine, Flinders University, Adelaide, SA 5001, Australia.
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