TTK/hMps1 participates in the regulation of DNA damage checkpoint response by phosphorylating CHK2 on threonine 68
TTK/hMps1 participates in the regulation of DNA damage checkpoint response by phosphorylating CHK2 on threonine 68
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DOI：
10.1074/jbc.m410152200
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发表时间：
2005-03-04
影响因子：
4.8
通讯作者：
Shieh, SY
中科院分区：
文献类型：
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作者：
Wei, JH;Chou, YF;Shieh, SY
CHK2/hCds1通过磷酸化几个重要靶点，如Cdc25和p53，在DNA损伤诱导的细胞周期检查点中发挥重要作用。为了更好地了解CHK2信号通路，我们进行了酵母双杂交筛选，以寻找潜在的CHK2相互作用蛋白。在这里，我们报道了有丝分裂检查点激酶TTK/hMps1作为一种新的chk2相互作用蛋白的鉴定。TTK/hMps1在体外直接磷酸化Thr-68上的CHK2。TTK激酶死亡突变体TTKD647A的表达干扰电离辐射或紫外线诱导的G(2)/M阻滞。有趣的是，CHK2 Thr-68磷酸化的诱导和一些下游事件，如细胞周期蛋白B1积累和Cdc2 tir -15磷酸化，也受到影响。此外，使用小干扰RNA消融TTK表达不仅导致CHK2 Thr-68磷酸化减少，还导致生长停滞受损。我们的结果与TTK在CHK2上游响应DNA损伤的模型一致，并提示纺锤体组装检查点和DNA损伤检查点之间可能存在串扰。
CHK2/hCds1 plays important roles in the DNA damage-induced cell cycle checkpoint by phosphorylating several important targets, such as Cdc25 and p53. To obtain a better understanding of the CHK2 signaling pathway, we have carried out a yeast two-hybrid screen to search for potential CHK2-interacting proteins. Here, we report the identification of the mitotic checkpoint kinase, TTK/hMps1, as a novel CHK2-interacting protein. TTK/hMps1 directly phosphorylates CHK2 on Thr-68 in vitro. Expression of a TTK kinase-dead mutant, TTKD647A, interferes with the G(2)/M arrest induced by either ionizing radiation or UV light. Interestingly, induction of CHK2 Thr-68 phosphorylation and of several downstream events, such as cyclin B1 accumulation and Cdc2 Tyr-15 phosphorylation, is also affected. Furthermore, ablation of TTK expression using small interfering RNA results not only in reduced CHK2 Thr-68 phosphorylation, but also in impaired growth arrest. Our results are consistent with a model in which TTK functions upstream from CHK2 in response to DNA damage and suggest possible cross-talk between the spindle assembly checkpoint and the DNA damage checkpoint.