Alao John P, Johansson-Sjölander Johanna, Rallis Charalampos, Sunnerhagen Per
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.
Microorganisms. 2020 Sep 30;8(10):1512. doi: 10.3390/microorganisms8101512.
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.
广泛消费的神经活性化合物咖啡因因其能够超越DNA损伤和复制检查点而引起了广泛关注。以前，Rad3及其同源物被认为是咖啡因抑制活性的靶点。后来的研究结果表明，雷帕霉素靶蛋白复合体1（TORC1）是咖啡因的首选靶点。有效的Cdc2抑制需要Wee1激酶的激活和Cdc25磷酸酶的抑制。TORC1、DNA损伤和环境应激反应途径都汇聚于Cdc25和Wee1。我们之前证明，咖啡因通过调节Cdc25的稳定性来超越DNA损伤检查点。咖啡因对细胞周期进程的影响类似于TORC1抑制的影响。此外，咖啡因激活Sty1调节的环境应激反应。因此，咖啡因可能调节多种信号通路，这些信号通路调节Cdc25和Wee1的水平、定位和活性。在这里，我们表明咖啡因的活性使Cdc25和Wee1都稳定。咖啡因和基因毒性剂对Wee1的稳定作用依赖于Rad24伴侣蛋白。有趣的是，咖啡因抑制了Wee1在DNA损伤时的积累。咖啡因可能通过在DNA损伤后通过抑制TORC1增加Cdc25活性和抑制Wee1来调节细胞周期进程，因为抑制TORC1会增加DNA损伤敏感性。
