RT Journal Article
SR Electronic
T1 The AMPK-TORC1 signalling axis regulates caffeine-mediated DNA damage checkpoint override and cell cycle effects in fission yeast
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.11.08.515652
DO 10.1101/2022.11.08.515652
A1 John. P. Alao
A1 Charalampos Rallis
YR 2022
UL http://biorxiv.org/content/early/2022/11/08/2022.11.08.515652.abstract
AB Caffeine is among the most widely consumed neuroactive compounds in the world. It induces DNA damage checkpoint signalling override and enhances sensitivity to DNA damaging agents. However, the precise underlying mechanisms have remained elusive. The Ataxia Telangiectasia Mutated (ATM) orthologue Rad3 has been proposed as the cellular target of caffeine. Nevertheless, recent studies suggest that the Target of Rapamycin Complex 1 (TORC1) might be the main target. In the fission yeast Schizosaccharomyces pombe (S. pombe), caffeine mimics the effects of activating the Sty1-regulated stress response and the AMP-Activated Protein Kinase (AMPK) homologue Ssp1-Ssp2 pathways on cell cycle progression. Direct inhibition of TORC1 with the ATP-competitive inhibitor torin1, is sufficient to override DNA damage checkpoint signalling. It is, therefore, plausible, that caffeine modulates cell cycle kinetics by indirectly suppressing TORC1 through activation of Ssp2. Deletion of ssp1 and ssp2 suppresses the effects of caffeine on cell cycle progression. In contrast, direct inhibition of TORC1 enhances DNA damage sensitivity in these mutants. These observations suggest that caffeine overrides DNA damage signalling, in part, via the indirect inhibition of TORC1 through Ssp2 activation. The AMPK-mTORC1 signalling axis plays an important role in aging and disease and presents a potential target for chemo- and radio-sensitization. Our results provide a clear understanding of the mechanism of how caffeine modulates cell cycle progression in the context of Ssp1-AMPKαSsp2-TORC1 signalling activities and can potentially aid in the development of novel dietary regimens, therapeutics, and chemo-sensitizing agents.Competing Interest StatementThe authors have declared no competing interest.