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Schwarz LV, Sandri FK, Scariot F, Delamare APL, Valera MJ, Carrau F, Echeverrigaray S. High nitrogen concentration causes G2/M arrest in Hanseniaspora vineae. Yeast 2023; 40:640-650. [PMID: 37997429 DOI: 10.1002/yea.3911] [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: 07/04/2023] [Revised: 10/26/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023] Open
Abstract
Yeasts have been widely used as a model to better understand cell cycle mechanisms and how nutritional and genetic factors can impact cell cycle progression. While nitrogen scarcity is well known to modulate cell cycle progression, the relevance of nitrogen excess for microorganisms has been overlooked. In our previous work, we observed an absence of proper entry into the quiescent state in Hanseniaspora vineae and identified a potential link between this behavior and nitrogen availability. Furthermore, the Hanseniaspora genus has gained attention due to a significant loss of genes associated with DNA repair and cell cycle. Thus, the aim of our study was to investigate the effects of varying nitrogen concentrations on H. vineae's cell cycle progression. Our findings demonstrated that nitrogen excess, regardless of the source, disrupts cell cycle progression and induces G2/M arrest in H. vineae after reaching the stationary phase. Additionally, we observed a viability decline in H. vineae cells in an ammonium-dependent manner, accompanied by increased production of reactive oxygen species, mitochondrial hyperpolarization, intracellular acidification, and DNA fragmentation. Overall, our study highlights the events of the cell cycle arrest in H. vineae induced by nitrogen excess and attempts to elucidate the possible mechanism triggering this absence of proper entry into the quiescent state.
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Affiliation(s)
- Luisa Vivian Schwarz
- Institute of Biotechnology, University of Caxias do Sul (UCS), Caxias do Sul, Rio Grande do Sul, Brazil
| | - Fernanda Knaach Sandri
- Institute of Biotechnology, University of Caxias do Sul (UCS), Caxias do Sul, Rio Grande do Sul, Brazil
| | - Fernando Scariot
- Institute of Biotechnology, University of Caxias do Sul (UCS), Caxias do Sul, Rio Grande do Sul, Brazil
| | | | - Maria Jose Valera
- Enology and Fermentation Biotechnology Area, Departamento Ciencia y Tecnología Alimentos, Facultad de Química, Universidad de la Republica, Montevideo, Uruguay
| | - Francisco Carrau
- Enology and Fermentation Biotechnology Area, Departamento Ciencia y Tecnología Alimentos, Facultad de Química, Universidad de la Republica, Montevideo, Uruguay
| | - Sergio Echeverrigaray
- Institute of Biotechnology, University of Caxias do Sul (UCS), Caxias do Sul, Rio Grande do Sul, Brazil
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Components of TOR and MAP kinase signaling control chemotropism and pathogenicity in the fungal pathogen Verticillium dahliae. Microbiol Res 2023; 271:127361. [PMID: 36921400 DOI: 10.1016/j.micres.2023.127361] [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: 10/21/2022] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 03/13/2023]
Abstract
Filamentous fungi can sense useful resources and hazards in their environment and direct growth of their hyphae accordingly. Chemotropism ensures access to nutrients, contact with other individuals (e.g., for mating), and interaction with hosts in the case of pathogens. Previous studies have revealed a complex chemotropic sensing landscape during host-pathogen interactions, but the underlying molecular machinery remains poorly characterized. Here we studied mechanisms controlling directed hyphal growth of the important plant-pathogenic fungus Verticillium dahliae towards different chemoattractants. We found that the homologs of the Rag GTPase Gtr1 and the GTPase-activating protein Tsc2, an activator and a repressor of the TOR kinase respectively, play important roles in hyphal chemotropism towards nutrients, plant-derived signals, and heterologous α-pheromone of Fusarium oxysporum. Furthermore, important roles of these regulators were identified in fungal development and pathogenicity. We also found that the mitogen-activated protein kinase (MAPK) Fus3 is required for chemotropism towards nutrients, while the G protein-coupled receptor (GPCR) Ste2 and the MAPK Slt2 control chemosensing of plant-derived signals and α-pheromone. Our study establishes V. dahliae as a suitable model system for the analysis of fungal chemotropism and discovers new components of chemotropic signaling during growth and host-pathogen interactions of V. dahliae.
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DuPré NC, Heng YJ, Raby BA, Glass K, Hart JE, Chu JH, Askew C, Eliassen AH, Hankinson SE, Kraft P, Laden F, Tamimi RM. Involvement of fine particulate matter exposure with gene expression pathways in breast tumor and adjacent-normal breast tissue. ENVIRONMENTAL RESEARCH 2020; 186:109535. [PMID: 32668536 PMCID: PMC7368092 DOI: 10.1016/j.envres.2020.109535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/18/2020] [Accepted: 04/12/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Fine particulate matter (PM2.5) has been associated with breast cancer specific mortality, particularly for women with Stage I cancer. We examined the biological pathways that are perturbed by PM2.5 exposures by analyzing gene expression measurements from breast tissue specimens. METHODS The Nurses' Health Studies (NHS and NHSII) are prospective cohorts with archival breast tissue specimens from breast cancer cases. Global gene expression data were ascertained with the Affymetrix Glue Human Transcriptome Array 3.0. PM2.5 was estimated using spatio-temporal models linked to participants' home addresses. All analyses were performed separately in tumor (n = 591) and adjacent-normal (n = 497) samples, and stratified by estrogen receptor (ER) status and stage. We used multivariable linear regression, gene-set enrichment analyses (GSEA), and the least squares kernel machine (LSKM) to assess whether 3-year cumulative average pre-diagnosis PM2.5 exposure was associated with breast-tissue gene expression pathways among predominately Stage I and II women (90.7%) and postmenopausal (81.2%) women. Replication samples (tumor, n = 245; adjacent-normal, n = 165) were measured on Affymetrix Human Transcriptome Array (HTA 2.0). RESULTS Overall, no pathways in the tumor area were significantly associated with PM2.5 exposure. Among 272 adjacent-normal samples from Stage I ER-positive women, PM2.5 was associated with perturbations in the oxidative phosphorylation, protein secretion, and mTORC1 signaling pathways (GSEA and LSKM p-values <0.05); however, results were not replicated in a small set of replication samples (n = 80). CONCLUSIONS PM2.5 was generally not associated with breast tissue gene expression though was suggested to perturb oxidative phosphorylation and regulation of proteins and cellular signaling in adjacent-normal breast tissue. More research is needed on the biological role of PM2.5 that influences breast tumor progression.
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Affiliation(s)
- Natalie C DuPré
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Epidemiology and Population Health, University of Louisville School of Public Health and Information Sciences, Louisville, KY, USA.
| | - Yujing J Heng
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Cancer Research Institute, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Benjamin A Raby
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kimberly Glass
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA; Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02215, USA
| | - Jaime E Hart
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Jen-Hwa Chu
- Section of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Catherine Askew
- Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - A Heather Eliassen
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Susan E Hankinson
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Peter Kraft
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02215, USA
| | - Francine Laden
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Rulla M Tamimi
- Channing Division of Network Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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Laribee RN, Weisman R. Nuclear Functions of TOR: Impact on Transcription and the Epigenome. Genes (Basel) 2020; 11:E641. [PMID: 32532005 PMCID: PMC7349558 DOI: 10.3390/genes11060641] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 12/15/2022] Open
Abstract
The target of rapamycin (TOR) protein kinase is at the core of growth factor- and nutrient-dependent signaling pathways that are well-known for their regulation of metabolism, growth, and proliferation. However, TOR is also involved in the regulation of gene expression, genomic and epigenomic stability. TOR affects nuclear functions indirectly through its activity in the cytoplasm, but also directly through active nuclear TOR pools. The mechanisms by which TOR regulates its nuclear functions are less well-understood compared with its cytoplasmic activities. TOR is an important pharmacological target for several diseases, including cancer, metabolic and neurological disorders. Thus, studies of the nuclear functions of TOR are important for our understanding of basic biological processes, as well as for clinical implications.
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Affiliation(s)
- R. Nicholas Laribee
- Department of Pathology and Laboratory Medicine, College of Medicine and Center for Cancer Research, University of Tennessee Health Science Center, 19 South Manassas, Cancer Research Building Rm 318, Memphis, TN 38163, USA
| | - Ronit Weisman
- Department of Natural and Life Sciences, The Open University of Israel, University Road 1, Ra’anana 4353701, Israel
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Esnault C, Lee M, Ham C, Levin HL. Transposable element insertions in fission yeast drive adaptation to environmental stress. Genome Res 2018; 29:85-95. [PMID: 30541785 PMCID: PMC6314160 DOI: 10.1101/gr.239699.118] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 11/15/2018] [Indexed: 01/06/2023]
Abstract
Cells are regularly exposed to a range of naturally occurring stress that can restrict growth or cause lethality. In response, cells activate expression networks with hundreds of genes that together increase resistance to common environmental insults. However, stress response networks can be insufficient to ensure survival, which raises the question of whether cells possess genetic programs that can promote adaptation to novel forms of stress. We found transposable element (TE) mobility in Schizosaccharomyces pombe was greatly increased when cells were exposed to unusual forms of stress such as heavy metals, caffeine, and the plasticizer phthalate. By subjecting TE-tagged cells to CoCl2, we found the TE integration provided the major path to resistance. Groups of insertions that provided resistance were linked to TOR regulation and metal response genes. We extended our study of adaptation by analyzing TE positions in 57 genetically distinct wild strains. The genomic positions of 1048 polymorphic LTRs were strongly associated with a range of stress response genes, indicating TE integration promotes adaptation in natural conditions. These data provide strong support for the idea, first proposed by Barbara McClintock, that TEs provide a system to modify the genome in response to stress.
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Affiliation(s)
- Caroline Esnault
- Section on Eukaryotic Transposable Elements, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Michael Lee
- Section on Eukaryotic Transposable Elements, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Chloe Ham
- Section on Eukaryotic Transposable Elements, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Henry L Levin
- Section on Eukaryotic Transposable Elements, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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Ali M, Bukhari SA, Ali M, Lee HW. Upstream signalling of mTORC1 and its hyperactivation in type 2 diabetes (T2D). BMB Rep 2018; 50:601-609. [PMID: 29187279 PMCID: PMC5749905 DOI: 10.5483/bmbrep.2017.50.12.206] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Indexed: 12/19/2022] Open
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) plays a major role in cell growth, proliferation, polarity, differentiation, development, and controls transitioning between anabolic and catabolic states of the cell. It collects almost all extracellular and intracellular signals from growth factors, nutrients, and maintains cellular homeostasis, and is involved in several pathological conditions including, neurodegeneration, Type 2 diabetes (T2D), obesity, and cancer. In this review, we summarize current knowledge of upstream signaling of mTORC1 to explain etiology of T2D and hypertriglyceridemia, in which state, the role of telomere attrition is explained. We discuss if chronic inhibition of mTORC1 can reverse adverse effects resulting from hyperactivation. In conclusion, we suggest the regulatory roles of telomerase (TERT) and hexokinase II (HKII) on mTORC1 as possible remedies to treat hyperactivation. The former inhibits mTORC1 under nutrient-rich while the latter under starved condition. We provide an idea of TOS (TOR signaling) motifs that can be used for regulation of mTORC1.
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Affiliation(s)
- Muhammad Ali
- Departments of Biochemistry, Government College University, Faisalabad, 38000 Pakistan
| | - Shazia Anwer Bukhari
- Departments of Biochemistry, Government College University, Faisalabad, 38000 Pakistan
| | - Muhammad Ali
- Departments of Zoology, Government College University, Faisalabad, 38000 Pakistan
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
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Ma Y, Vassetzky Y, Dokudovskaya S. mTORC1 pathway in DNA damage response. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1293-1311. [PMID: 29936127 DOI: 10.1016/j.bbamcr.2018.06.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 12/27/2022]
Abstract
Living organisms have evolved various mechanisms to control their metabolism and response to various stresses, allowing them to survive and grow in different environments. In eukaryotes, the highly conserved mechanistic target of rapamycin (mTOR) signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of cellular metabolism, proliferation and survival. A growing body of evidence indicates that mTOR signaling is closely related to another cellular protection mechanism, the DNA damage response (DDR). Many factors important for the DDR are also involved in the mTOR pathway. In this review, we discuss how these two pathways communicate to ensure an efficient protection of the cell against metabolic and genotoxic stresses. We also describe how anticancer therapies benefit from simultaneous targeting of the DDR and mTOR pathways.
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Affiliation(s)
- Yinxing Ma
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France
| | - Yegor Vassetzky
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France
| | - Svetlana Dokudovskaya
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France.
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Cohen A, Habib A, Laor D, Yadav S, Kupiec M, Weisman R. TOR complex 2 in fission yeast is required for chromatin-mediated gene silencing and assembly of heterochromatic domains at subtelomeres. J Biol Chem 2018; 293:8138-8150. [PMID: 29632066 DOI: 10.1074/jbc.ra118.002270] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/14/2018] [Indexed: 12/21/2022] Open
Abstract
The conserved serine/threonine protein kinase target of rapamycin (TOR) is a major regulator of eukaryotic cellular and organismal growth and a valuable target for drug therapy. TOR forms the core of two evolutionary conserved complexes, TOR complex 1 (TORC1) and TORC2. In the fission yeast Schizosaccharomyces pombe, TORC2 responds to glucose levels and, by activating the protein kinase Gad8 (an orthologue of human AKT), is required for well-regulated cell cycle progression, starvation responses, and cell survival. Here, we report that TORC2-Gad8 is also required for gene silencing and the formation of heterochromatin at the S. pombe mating-type locus and at subtelomeric regions. Deletion of TORC2-Gad8 resulted in loss of the heterochromatic modification of histone 3 lysine 9 dimethylation (H3K9me2) and an increase in euchromatic modifications, including histone 3 lysine 4 trimethylation (H3K4me3) and histone 4 lysine 16 acetylation (H4K16Ac). Accumulation of RNA polymerase II (Pol II) at subtelomeric genes in TORC2-Gad8 mutant cells indicated a defect in silencing at the transcriptional level. Moreover, a concurrent decrease in histone 4 lysine 20 dimethylation (H4K20me2) suggested elevated histone turnover. Loss of gene silencing in cells lacking TORC2-Gad8 is partially suppressed by loss of the anti-silencer Epe1 and fully suppressed by loss of the Pol II-associated Paf1 complex, two chromatin regulators that have been implicated in heterochromatin stability and spreading. Taken together, our findings suggest that TORC2-Gad8 signaling contributes to epigenetic stability at subtelomeric regions and the mating-type locus in S. pombe.
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Affiliation(s)
- Adiel Cohen
- Department of Natural and Life Sciences, Open University of Israel, University Road 1, 4353701 Ranana, Israel
| | - Aline Habib
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69977801, Tel Aviv, Israel
| | - Dana Laor
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69977801, Tel Aviv, Israel
| | - Sudhanshu Yadav
- Department of Natural and Life Sciences, Open University of Israel, University Road 1, 4353701 Ranana, Israel
| | - Martin Kupiec
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69977801, Tel Aviv, Israel
| | - Ronit Weisman
- Department of Natural and Life Sciences, Open University of Israel, University Road 1, 4353701 Ranana, Israel.
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Giguère V. Canonical signaling and nuclear activity of mTOR-a teamwork effort to regulate metabolism and cell growth. FEBS J 2018; 285:1572-1588. [PMID: 29337437 DOI: 10.1111/febs.14384] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 12/21/2017] [Accepted: 01/10/2018] [Indexed: 01/07/2023]
Abstract
Mechanistic (or mammalian) target of rapamycin (mTOR) is a kinase that regulates almost all functions related to cell growth and metabolism in response to extra- and intracellular stimuli, such as availability of nutrients, the presence of growth factors, or the energy status of the cell. As part of two distinct protein complexes, mTORC1 and mTORC2, the kinase has been shown to influence cell growth and proliferation by controlling ribosome biogenesis, mRNA translation, carbohydrate and lipid metabolism, protein degradation, autophagy as well as microtubule and actin dynamics. In addition to these well-characterized functions, mTOR can also influence gene transcription. While most studies focused on investigating how canonical mTOR signaling regulates the activity of transcription factors outside the nucleus, recent findings point to a more direct role for mTOR as a transcription factor operating on chromatin in the nucleus. In particular, recent genome-wide identification of mTOR targets on chromatin reveals that its activities in the nucleus and cytoplasm are functionally and biologically linked, thus uncovering a novel paradigm in mTOR function.
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Affiliation(s)
- Vincent Giguère
- Departments of Biochemistry, Medicine and Oncology, Faculty of Medicine, Goodman Cancer Research Centre, McGill University, Montréal, Canada
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10
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Vadla R, Haldar D. Mammalian target of rapamycin complex 2 (mTORC2) controls glycolytic gene expression by regulating Histone H3 Lysine 56 acetylation. Cell Cycle 2018; 17:110-123. [PMID: 29143563 DOI: 10.1080/15384101.2017.1404207] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Metabolic reprogramming is a hallmark of cancer cells, but the mechanisms are not well understood. The mammalian target of rapamycin complex 2 (mTORC2) controls cell growth and proliferation and plays a critical role in metabolic reprogramming in glioma. mTORC2 regulates cellular processes such as cell survival, metabolism, and proliferation by phosphorylation of AGC kinases. Components of mTORC2 are shown to localize to the nucleus, but whether mTORC2 modulates epigenetic modifications to regulate gene expression is not known. Here, we identified histone H3 lysine 56 acetylation (H3K56Ac) is regulated by mTORC2 and show that global H3K56Ac levels were downregulated on mTORC2 knockdown but not on mTORC1 knockdown. mTORC2 promotes H3K56Ac in a tuberous sclerosis complex 1/2 (TSC1/2) mediated signaling pathway. We show that knockdown of sirtuin6 (SIRT6) prevented H3K56 deacetylation in mTORC2 depleted cells. Using glioma model consisting of U87EGFRvIII cells, we established that mTORC2 promotes H3K56Ac in glioma. Finally, we show that mTORC2 regulates the expression of glycolytic genes by regulating H3K56Ac levels at the promoters of these genes in glioma cells and depletion of mTOR leads to increased recruitment of SIRT6 to these promoters. Collectively, these results identify mTORC2 signaling pathway positively promotes H3K56Ac through which it may mediate metabolic reprogramming in glioma.
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Affiliation(s)
- Raghavendra Vadla
- a Centre for DNA Fingerprinting and Diagnostics , Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Hyderabad 500039 , Ranga Reddy District , India.,b Graduate Studies , Manipal University , Manipal , India
| | - Devyani Haldar
- a Centre for DNA Fingerprinting and Diagnostics , Survey Nos. 728, 729, 730 & 734, Opposite Uppal Water Tank, Beside BSNL T E Building, Uppal, Hyderabad 500039 , Ranga Reddy District , India
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11
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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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12
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Grove A. Control of RNA polymerase II-transcribed genes by direct binding of TOR kinase. Curr Genet 2017; 64:131-135. [DOI: 10.1007/s00294-017-0738-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
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13
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Panday A, Gupta A, Srinivasa K, Xiao L, Smith MD, Grove A. DNA damage regulates direct association of TOR kinase with the RNA polymerase II-transcribed HMO1 gene. Mol Biol Cell 2017; 28:2449-2459. [PMID: 28701348 PMCID: PMC5576907 DOI: 10.1091/mbc.e17-01-0024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 06/05/2017] [Accepted: 07/07/2017] [Indexed: 01/29/2023] Open
Abstract
In yeast, Hmo1p is important for communicating target of rapamycin (TOR) kinase activity to downstream targets. Results show that TOR kinase controls expression of the HMO1 gene and that an important component of this regulation is its direct association with the HMO1 gene. The implications are that TOR kinase may have more elaborate nuclear functions. The mechanistic target of rapamycin complex 1 (mTORC1) senses nutrient sufficiency and cellular stress. When mTORC1 is inhibited, protein synthesis is reduced in an intricate process that includes a concerted down-regulation of genes encoding rRNA and ribosomal proteins. The Saccharomyces cerevisiae high-mobility group protein Hmo1p has been implicated in coordinating this response to mTORC1 inhibition. We show here that Tor1p binds directly to the HMO1 gene (but not to genes that are not linked to ribosome biogenesis) and that the presence of Tor1p is associated with activation of gene activity. Persistent induction of DNA double-strand breaks or mTORC1 inhibition by rapamycin results in reduced levels of HMO1 mRNA, but only in the presence of Tor1p. This down-regulation is accompanied by eviction of Ifh1p and recruitment of Crf1p, followed by concerted dissociation of Hmo1p and Tor1p. These findings uncover a novel role for TOR kinase in control of gene activity by direct association with an RNA polymerase II–transcribed gene.
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Affiliation(s)
- Arvind Panday
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Ashish Gupta
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Kavitha Srinivasa
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Lijuan Xiao
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Mathew D Smith
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Anne Grove
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
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Abstract
Eukaryotic genomes are packaged in chromatin. The higher-order organization of nucleosome core particles is controlled by the association of the intervening linker DNA with either the linker histone H1 or high mobility group box (HMGB) proteins. While H1 is thought to stabilize the nucleosome by preventing DNA unwrapping, the DNA bending imposed by HMGB may propagate to the nucleosome to destabilize chromatin. For metazoan H1, chromatin compaction requires its lysine-rich C-terminal domain, a domain that is buried between globular domains in the previously characterized yeast Saccharomyces cerevisiae linker histone Hho1p. Here, we discuss the functions of S. cerevisiae HMO1, an HMGB family protein unique in containing a terminal lysine-rich domain and in stabilizing genomic DNA. On ribosomal DNA (rDNA) and genes encoding ribosomal proteins, HMO1 appears to exert its role primarily by stabilizing nucleosome-free regions or "fragile" nucleosomes. During replication, HMO1 likewise appears to ensure low nucleosome density at DNA junctions associated with the DNA damage response or the need for topoisomerases to resolve catenanes. Notably, HMO1 shares with the mammalian linker histone H1 the ability to stabilize chromatin, as evidenced by the absence of HMO1 creating a more dynamic chromatin environment that is more sensitive to nuclease digestion and in which chromatin-remodeling events associated with DNA double-strand break repair occur faster; such chromatin stabilization requires the lysine-rich extension of HMO1. Thus, HMO1 appears to have evolved a unique linker histone-like function involving the ability to stabilize both conventional nucleosome arrays as well as DNA regions characterized by low nucleosome density or the presence of noncanonical nucleosomes.
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Cohen A, Kupiec M, Weisman R. Gad8 Protein Is Found in the Nucleus Where It Interacts with the MluI Cell Cycle Box-binding Factor (MBF) Transcriptional Complex to Regulate the Response to DNA Replication Stress. J Biol Chem 2016; 291:9371-81. [PMID: 26912660 DOI: 10.1074/jbc.m115.705251] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 12/31/2022] Open
Abstract
The target of rapamycin (TOR) kinase is found at the core of two evolutionarily conserved complexes known as TOR complexes 1 and 2 (TORC1 and TORC2). In fission yeast, TORC2 is dispensable for proliferation under optimal growth conditions but is required for starvation and stress responses. We have previously reported that loss of function of TORC2 renders cells highly sensitive to DNA replication stress; however, the mechanism underlying this sensitivity is unknown. TORC2 has one known direct substrate, the kinase Gad8, which is related to AKT in human cells. Here we show that both TORC2 and its substrate Gad8 are found in the nucleus and are bound to the chromatin. We also demonstrate that Gad8 physically interacts with the MluI cell cycle box-binding factor (MBF) transcription complex that regulates the G1/S progression and the response to DNA stress. In mutant cells lacking TORC2 or Gad8, the binding of the MBF complex to its cognate promoters is compromised, and the induction of MBF target genes in response to DNA replication stress is reduced. Consistently, the protein levels of Cdt2 and Cig2, two MBF target genes, are reduced in the absence of TORC2-Gad8 signaling. Taken together, our findings highlight critical functions of TORC2 in the nucleus and suggest a role in surviving DNA replication stress via transcriptional regulation of MBF target genes.
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Affiliation(s)
- Adiel Cohen
- From the Department of Natural and Life Sciences, The Open University of Israel, University Road 1, 4353701 Raanana, Israel and
| | - Martin Kupiec
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Ronit Weisman
- From the Department of Natural and Life Sciences, The Open University of Israel, University Road 1, 4353701 Raanana, Israel and
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ELABELA Is an Endogenous Growth Factor that Sustains hESC Self-Renewal via the PI3K/AKT Pathway. Cell Stem Cell 2015; 17:435-47. [DOI: 10.1016/j.stem.2015.08.010] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 05/12/2015] [Accepted: 08/12/2015] [Indexed: 12/17/2022]
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17
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Moreno-Torres M, Jaquenoud M, De Virgilio C. TORC1 controls G1-S cell cycle transition in yeast via Mpk1 and the greatwall kinase pathway. Nat Commun 2015; 6:8256. [PMID: 26356805 PMCID: PMC4579850 DOI: 10.1038/ncomms9256] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 08/03/2015] [Indexed: 01/16/2023] Open
Abstract
The target of rapamycin complex 1 (TORC1) pathway couples nutrient, energy and hormonal signals with eukaryotic cell growth and division. In yeast, TORC1 coordinates growth with G1–S cell cycle progression, also coined as START, by favouring the expression of G1 cyclins that activate cyclin-dependent protein kinases (CDKs) and by destabilizing the CDK inhibitor Sic1. Following TORC1 downregulation by rapamycin treatment or nutrient limitation, clearance of G1 cyclins and C-terminal phosphorylation of Sic1 by unknown protein kinases are both required for Sic1 to escape ubiquitin-dependent proteolysis prompted by its flagging via the SCFCdc4 (Skp1/Cul1/F-box protein) ubiquitin ligase complex. Here we show that the stabilizing phosphorylation event within the C-terminus of Sic1 requires stimulation of the mitogen-activated protein kinase, Mpk1, and inhibition of the Cdc55 protein phosphatase 2A (PP2ACdc55) by greatwall kinase-activated endosulfines. Thus, Mpk1 and the greatwall kinase pathway serve TORC1 to coordinate the phosphorylation status of Sic1 and consequently START with nutrient availability. The target of rapamycin complex 1 (TORC1) pathway couples nutrient availability with cell growth and division by destabilizing the cyclin-dependent kinase (CDK) inhibitor Sic1. Here the authors show that TORC1 downregulation leads to stabilization of Sic1 via phosphorylation by the MAP kinase Mpk1 and inhibition of dephosphorylation via the greatwall kinase pathway.
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Affiliation(s)
- Marta Moreno-Torres
- Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg CH-1700, Switzerland
| | - Malika Jaquenoud
- Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg CH-1700, Switzerland
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg CH-1700, Switzerland
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18
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Abstract
Based on own translational research of the biochemical and hormonal effects of cow's milk consumption in humans, this review presents milk as a signaling system of mammalian evolution that activates the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), the pivotal regulator of translation. Milk, a mammary gland-derived secretory product, is required for species-specific gene-nutrient interactions that promote appropriate growth and development of the newborn mammal. This signaling system is highly conserved and tightly controlled by the lactation genome. Milk is sufficient to activate mTORC1, the crucial regulator of protein, lipid, and nucleotide synthesis orchestrating anabolism, cell growth and proliferation. To fulfill its mTORC1-activating function, milk delivers four key metabolic messengers: (1) essential branched-chain amino acids (BCAAs); (2) glutamine; (3) palmitic acid; and (4) bioactive exosomal microRNAs, which in a synergistical fashion promote mTORC1-dependent translation. In all mammals except Neolithic humans, postnatal activation of mTORC1 by milk intake is restricted to the postnatal lactation period. It is of critical concern that persistent hyperactivation of mTORC1 is associated with aging and the development of age-related disorders such as obesity, type 2 diabetes mellitus, cancer, and neurodegenerative diseases. Persistent mTORC1 activation promotes endoplasmic reticulum (ER) stress and drives an aimless quasi-program, which promotes aging and age-related diseases.
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19
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Zhou X, Clister TL, Lowry PR, Seldin MM, Wong GW, Zhang J. Dynamic Visualization of mTORC1 Activity in Living Cells. Cell Rep 2015; 10:1767-1777. [PMID: 25772363 DOI: 10.1016/j.celrep.2015.02.031] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 01/15/2015] [Accepted: 02/09/2015] [Indexed: 12/18/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) senses diverse signals to regulate cell growth and metabolism. It has become increasingly clear that mTORC1 activity is regulated in time and space inside the cell, but direct interrogation of such spatiotemporal regulation is challenging. Here, we describe a genetically encoded mTORC1 activity reporter (TORCAR) that exhibits a change in FRET in response to phosphorylation by mTORC1. Co-imaging mTORC1 activity and calcium dynamics revealed that a growth-factor-induced calcium transient contributes to mTORC1 activity. Dynamic activity maps generated with the use of subcellularly targeted TORCAR uncovered mTORC1 activity not only in cytosol and at the lysosome but also in the nucleus and at the plasma membrane. Furthermore, a wide distribution of activities was observed upon growth factor stimulation, whereas leucine ester, an amino acid surrogate, induces more compartmentalized activities at the lysosome and in the nucleus. Thus, mTORC1 activities are spatiotemporally regulated in a signal-specific manner.
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Affiliation(s)
- Xin Zhou
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Terri L Clister
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Pamela R Lowry
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Marcus M Seldin
- Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - G William Wong
- Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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20
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Doi A, Fujimoto A, Sato S, Uno T, Kanda Y, Asami K, Tanaka Y, Kita A, Satoh R, Sugiura R. Chemical genomics approach to identify genes associated with sensitivity to rapamycin in the fission yeastSchizosaccharomyces pombe. Genes Cells 2015; 20:292-309. [DOI: 10.1111/gtc.12223] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/13/2014] [Indexed: 02/02/2023]
Affiliation(s)
- Akira Doi
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
- Japan Society for the Promotion of Science; 1-8 Chiyoda-ku Tokyo 102-8472 Japan
| | - Ayumi Fujimoto
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Shun Sato
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Takaya Uno
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Yuki Kanda
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Keita Asami
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Yuriko Tanaka
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Ayako Kita
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Ryosuke Satoh
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Reiko Sugiura
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
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21
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Landes Highlights. Nucleus 2014. [PMCID: PMC4133213 DOI: 10.4161/nucl.28986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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