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Alao JP, Legon L, Rallis C. Crosstalk between the mTOR and DNA Damage Response Pathways in Fission Yeast. Cells 2021; 10:cells10020305. [PMID: 33540829 PMCID: PMC7913062 DOI: 10.3390/cells10020305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 12/14/2022] Open
Abstract
Cells have developed response systems to constantly monitor environmental changes and accordingly adjust growth, differentiation, and cellular stress programs. The evolutionarily conserved, nutrient-responsive, mechanistic target of rapamycin signaling (mTOR) pathway coordinates basic anabolic and catabolic cellular processes such as gene transcription, protein translation, autophagy, and metabolism, and is directly implicated in cellular and organismal aging as well as age-related diseases. mTOR mediates these processes in response to a broad range of inputs such as oxygen, amino acids, hormones, and energy levels, as well as stresses, including DNA damage. Here, we briefly summarize data relating to the interplays of the mTOR pathway with DNA damage response pathways in fission yeast, a favorite model in cell biology, and how these interactions shape cell decisions, growth, and cell-cycle progression. We, especially, comment on the roles of caffeine-mediated DNA-damage override. Understanding the biology of nutrient response, DNA damage and related pharmacological treatments can lead to the design of interventions towards improved cellular and organismal fitness, health, and survival.
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Affiliation(s)
- John-Patrick Alao
- ZEAB Therapeutic, University of East London, Stratford Campus, Water Lane, Stratford, London E15 4LZ, UK;
| | - Luc Legon
- School of Health, Sport and Bioscience, University of East London, Stratford Campus, Water Lane, Stratford, London E15 4LZ, UK;
| | - Charalampos Rallis
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
- Correspondence:
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Alao JP, Johansson-Sjölander J, Rallis C, Sunnerhagen P. Caffeine Stabilises Fission Yeast Wee1 in a Rad24-Dependent Manner but Attenuates Its Expression in Response to DNA Damage. Microorganisms 2020; 8:microorganisms8101512. [PMID: 33008060 PMCID: PMC7600152 DOI: 10.3390/microorganisms8101512] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/17/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
The widely consumed neuroactive compound caffeine has generated much interest due to its ability to override the DNA damage and replication checkpoints. Previously Rad3 and its homologues was thought to be the target of caffeine’s inhibitory activity. Later findings indicate that the Target of Rapamycin Complex 1 (TORC1) is the preferred target of caffeine. Effective Cdc2 inhibition requires both the activation of the Wee1 kinase and inhibition of the Cdc25 phosphatase. The TORC1, DNA damage, and environmental stress response pathways all converge on Cdc25 and Wee1. We previously demonstrated that caffeine overrides DNA damage checkpoints by modulating Cdc25 stability. The effect of caffeine on cell cycle progression resembles that of TORC1 inhibition. Furthermore, caffeine activates the Sty1 regulated environmental stress response. Caffeine may thus modulate multiple signalling pathways that regulate Cdc25 and Wee1 levels, localisation and activity. Here we show that the activity of caffeine stabilises both Cdc25 and Wee1. The stabilising effect of caffeine and genotoxic agents on Wee1 was dependent on the Rad24 chaperone. Interestingly, caffeine inhibited the accumulation of Wee1 in response to DNA damage. Caffeine may modulate cell cycle progression through increased Cdc25 activity and Wee1 repression following DNA damage via TORC1 inhibition, as TORC1 inhibition increased DNA damage sensitivity.
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Affiliation(s)
- John P Alao
- School of Health, Sports and Bioscience, University of East London, Stratford Campus, London E15 4LZ, UK
- Department of Chemistry and Molecular Biology, University of Gothenburg, P.O. Box 462, SE-405 30 Gothenburg, Sweden
| | - Johanna Johansson-Sjölander
- Department of Chemistry and Molecular Biology, University of Gothenburg, P.O. Box 462, SE-405 30 Gothenburg, Sweden
| | - Charalampos Rallis
- School of Health, Sports and Bioscience, University of East London, Stratford Campus, London E15 4LZ, UK
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
| | - Per Sunnerhagen
- Department of Chemistry and Molecular Biology, University of Gothenburg, P.O. Box 462, SE-405 30 Gothenburg, Sweden
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Alao JP, Sunnerhagen P. Caffeine as a tool for investigating the integration of Cdc25 phosphorylation, activity and ubiquitin-dependent degradation in Schizosaccharomyces pombe. Cell Div 2020; 15:10. [PMID: 32612670 PMCID: PMC7322915 DOI: 10.1186/s13008-020-00066-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/08/2020] [Indexed: 12/27/2022] Open
Abstract
The evolutionarily conserved Cdc25 phosphatase is an essential protein that removes inhibitory phosphorylation moieties on the mitotic regulator Cdc2. Together with the Wee1 kinase, a negative regulator of Cdc2 activity, Cdc25 is thus a central regulator of cell cycle progression in Schizosaccharomyces pombe. The expression and activity of Cdc25 is dependent on the activity of the Target of Rapamycin Complex 1 (TORC1). TORC1 inhibition leads to the activation of Cdc25 and repression of Wee1, leading to advanced entry into mitosis. Withdrawal of nitrogen leads to rapid Cdc25 degradation via the ubiquitin- dependent degradation pathway by the Pub1 E3- ligase. Caffeine is believed to mediate the override of DNA damage checkpoint signalling, by inhibiting the activity of the ataxia telangiectasia mutated (ATM)/Rad3 homologues. This model remains controversial, as TORC1 appears to be the preferred target of caffeine in vivo. Recent studies suggest that caffeine induces DNA damage checkpoint override by inducing the nuclear accumulation of Cdc25 in S. pombe. Caffeine may thus modulate Cdc25 activity and stability via inhibition of TORC1. A clearer understanding of the mechanisms by which caffeine stabilises Cdc25, may provide novel insights into how TORC1 and DNA damage signalling is integrated.
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Affiliation(s)
- John P Alao
- School of Health, Sports and Bioscience, University of East London, Stratford Campus, London, E15 4LZ UK.,Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, Gothenburg, SE- 405 30 Sweden
| | - Per Sunnerhagen
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, Gothenburg, SE- 405 30 Sweden
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A Redox-Sensitive Thiol in Wis1 Modulates the Fission Yeast Mitogen-Activated Protein Kinase Response to H 2O 2 and Is the Target of a Small Molecule. Mol Cell Biol 2020; 40:MCB.00346-19. [PMID: 31932483 PMCID: PMC7076255 DOI: 10.1128/mcb.00346-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 01/03/2020] [Indexed: 12/17/2022] Open
Abstract
Oxidation of a highly conserved cysteine (Cys) residue located in the kinase activation loop of mitogen-activated protein kinase kinases (MAPKK) inactivates mammalian MKK6. This residue is conserved in the fission yeast Schizosaccharomyces pombe MAPKK Wis1, which belongs to the H2O2-responsive MAPK Sty1 pathway. Here, we show that H2O2 reversibly inactivates Wis1 through this residue (C458) in vitro. Oxidation of a highly conserved cysteine (Cys) residue located in the kinase activation loop of mitogen-activated protein kinase kinases (MAPKK) inactivates mammalian MKK6. This residue is conserved in the fission yeast Schizosaccharomyces pombe MAPKK Wis1, which belongs to the H2O2-responsive MAPK Sty1 pathway. Here, we show that H2O2 reversibly inactivates Wis1 through this residue (C458) in vitro. We found that C458 is oxidized in vivo and that serine replacement of this residue significantly enhances Wis1 activation upon addition of H2O2. The allosteric MAPKK inhibitor INR119, which binds in a pocket next to the activation loop and C458, prevented the inhibition of Wis1 by H2O2in vitro and significantly increased Wis1 activation by low levels of H2O2in vivo. We propose that oxidation of C458 inhibits Wis1 and that INR119 cancels out this inhibitory effect by binding close to this residue. Kinase inhibition through the oxidation of a conserved Cys residue in MKK6 (C196) is thus conserved in the S. pombe MAPKK Wis1.
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Nunes VS, Moretti NS, da Silva MS, Elias MC, Janzen CJ, Schenkman S. Trimethylation of histone H3K76 by Dot1B enhances cell cycle progression after mitosis in Trypanosoma cruzi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118694. [PMID: 32151656 DOI: 10.1016/j.bbamcr.2020.118694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 12/11/2022]
Abstract
Dot1 enzymes are histone methyltransferases that mono-, di- and trimethylate lysine 79 of histone H3 to affect several nuclear processes. The functions of these different methylation states are still largely unknown. Trypanosomes, which are flagellated protozoa that cause several parasitic diseases, have two Dot1 homologues. Dot1A catalyzes the mono- and dimethylation of lysine 76 during late G2 and mitosis, and Dot1B catalyzes trimethylation, which is a modification found in all stages of the cell cycle. Here, we generated Trypanosoma cruzi lines lacking Dot1B. Deletion of one allele resulted in parasites with increased levels of mono- and dimethylation and a reduction in H3K76me3. In the full knockout (DKO), no trimethylation was observed. Both the DKO and the single knockout (SKO) showed aberrant morphology and decreased growth due to cell cycle arrest after G2. This phenotype could be rescued by caffeine in the DKO, as caffeine is a checkpoint inhibitor of the cell cycle. The knockouts also phosphorylated γH2A without producing extensive DNA breaks, and Dot1B-depleted cells were more susceptible to general checkpoint kinase inhibitors, suggesting that a lack of H3K76 trimethylation prevents the initiation and/or completion of cytokinesis.
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Affiliation(s)
- Vinicius Santana Nunes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil; Centro de Ensino, Pesquisa e Inovação, Hospital Evangélico de Vila Velha, 29118-060 Vila Velha, ES, Brazil
| | - Nilmar Silvio Moretti
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil
| | | | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, Brazil
| | - Christian J Janzen
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sergio Schenkman
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil.
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Sjölander JJ, Sunnerhagen P. The fission yeast FHIT homolog affects checkpoint control of proliferation and is regulated by mitochondrial electron transport. Cell Biol Int 2019; 44:412-423. [PMID: 31538680 PMCID: PMC7003880 DOI: 10.1002/cbin.11241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 09/15/2019] [Indexed: 11/08/2022]
Abstract
Genetic analysis has strongly implicated human FHIT (Fragile Histidine Triad) as a tumor suppressor gene, being mutated in a large proportion of early‐stage cancers. The functions of the FHIT protein have, however, remained elusive. Here, we investigated aph1+, the fission yeast homolog of FHIT, for functions related to checkpoint control and oxidative metabolism. In sublethal concentrations of DNA damaging agents, aph1Δ mutants grew with a substantially shorter lag phase. In aph1Δ mutants carrying a hypomorphic allele of cds1 (the fission yeast homolog of Chk2), in addition, increased chromosome fragmentation and missegregation were found. We also found that under hypoxia or impaired electron transport function, the Aph1 protein level was strongly depressed. Previously, FHIT has been linked to regulation of the human 9‐1‐1 checkpoint complex constituted by Hus1, Rad1, and Rad9. In Schizosaccharomyces pombe, the levels of all three 9‐1‐1 proteins are all downregulated by hypoxia in similarity with Aph1. Moreover, deletion of the aph1+ gene reduced the Rad1 protein level, indicating a direct relationship between these two proteins. We conclude that the fission yeast FHIT homolog has a role in modulating DNA damage checkpoint function, possibly through an effect on the 9‐1‐1 complex, and that this effect may be critical under conditions of limiting oxidative metabolism and reoxygenation.
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Affiliation(s)
- Johanna J Sjölander
- Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, P.O. Box 462, Göteborg, SE-405 30, Sweden
| | - Per Sunnerhagen
- Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, P.O. Box 462, Göteborg, SE-405 30, Sweden
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Genotoxic effect of caffeine in Yarrowia lipolytica cells deficient in DNA repair mechanisms. Arch Microbiol 2019; 201:991-998. [PMID: 31025056 DOI: 10.1007/s00203-019-01658-4] [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: 08/09/2018] [Revised: 04/05/2019] [Accepted: 04/10/2019] [Indexed: 01/01/2023]
Abstract
Caffeine is a compound that can exert physiological-beneficial effects in the organism. Nevertheless, there are controversies about its protective-antioxidant and/or its negative genotoxic effect. To abound on the analysis of the possible genotoxic/antioxidant effect of caffeine, we used as research model the yeast Yarrowia lipolytica parental strain, and mutant strains (∆rad52 and ∆ku80), which are deficient in the DNA repair mechanisms. Caffeine (5 mM) showed a cytostatic effect on all strains, but after 72 h of incubation the parental and ∆ku80 strains were able to recover of this inhibitory effect on growth, whereas ∆rad52 was unable to recover. When cells were pre-incubated with caffeine and H2O2 or incubated with a mixture of both agents, a higher inhibitory effect on growth of mutant strains was observed and this effect was noticeably greater for the Δrad52 strain. The toxic effect of caffeine appears to be through a mechanism of DNA damage (genotoxic effect) that involves DSB generation since, in all tested conditions, the growth of Δrad52 strain (cells deficient in HR DNA repair mechanism) was more severely affected.
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Gene Expression of Pneumocystis murina after Treatment with Anidulafungin Results in Strong Signals for Sexual Reproduction, Cell Wall Integrity, and Cell Cycle Arrest, Indicating a Requirement for Ascus Formation for Proliferation. Antimicrob Agents Chemother 2018; 62:AAC.02513-17. [PMID: 29463544 PMCID: PMC5923105 DOI: 10.1128/aac.02513-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/10/2018] [Indexed: 01/03/2023] Open
Abstract
The echinocandins are a class of antifungal agents that target β-1,3-d-glucan (BG) biosynthesis. In the ascigerous Pneumocystis species, treatment with these drugs depletes the ascus life cycle stage, which contains BG, but large numbers of forms which do not express BG remain in the infected lungs. In the present study, the gene expression profiles of Pneumocystis murina were compared between infected, untreated mice and mice treated with anidulafungin for 2 weeks to understand the metabolism of the persisting forms. Almost 80 genes were significantly up- or downregulated. Like other fungi exposed to echinocandins, genes associated with sexual replication, cell wall integrity, cell cycle arrest, and stress comprised the strongest upregulated signals in P. murina from the treated mice. The upregulation of the P. murina β-1,3-d-glucan endohydrolase and endo-1,3-glucanase was notable and may explain the disappearance of the existing asci in the lungs of treated mice since both enzymes can degrade BG. The biochemical measurement of BG in the lungs of treated mice and fluorescence microscopy with an anti-BG antibody supported the loss of BG. Downregulated signals included genes involved in cell replication, genome stability, and ribosomal biogenesis and function and the Pneumocystis-specific genes encoding the major surface glycoproteins (Msg). These studies suggest that P. murina attempted to undergo sexual replication in response to a stressed environment and was halted in any type of proliferative cycle, likely due to a lack of BG. Asci appear to be a required part of the life cycle stage of Pneumocystis, and BG may be needed to facilitate progression through the life cycle via sexual replication.
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