CHK2 kinase promotes pre-mRNA splicing via phosphorylating CDK11(p110).
CHK2 kinase promotes pre-mRNA splicing via phosphorylating CDK11(p110).
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DOI：
10.1038/onc.2012.535
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发表时间：
2014-01-02
期刊：
影响因子：
8
通讯作者：
Kim ST
中科院分区：
文献类型：
--
作者：
Choi HH;Choi HK;Jung SY;Hyle J;Kim BJ;Yoon K;Cho EJ;Youn HD;Lahti JM;Qin J;Kim ST
CHK2 激酶是许多细胞对基因毒性应激（包括电离辐射和拓扑异构酶抑制剂）反应的关键介质。电离辐射后，CHK2 被 ATM 激酶激活，并通过磷酸化 p53 和 Brca1 等下游靶蛋白来调节 S 期和 G1-S 检查点、细胞凋亡和 DNA 修复。此外，CHK2被认为是多器官癌症易感基因。在这项研究中，我们使用串联亲和纯化策略来鉴定与 CHK2 激酶相互作用的蛋白质。 CDK11p110 激酶参与前 mRNA 剪接和转录，被鉴定为 CHK2 相互作用蛋白。 CHK2 激酶在体外磷酸化 CDK11p110 的丝氨酸 737。出乎意料的是，CHK2 激酶以 DNA 损伤无关的方式组成性磷酸化 CDK11p110。在分子水平上，CDK11p110 磷酸化是同二聚化所必需的，而不影响其激酶活性。 CHK2 的过度表达促进前 mRNA 剪接。相反，CHK2 缺失会降低内源剪接活性。 CDK11p110 中的磷酸化位点突变为丙氨酸会消除其剪接激活活性。这些结果提供了第一个证据，表明 CHK2 激酶通过磷酸化 CDK11p110 促进前 mRNA 剪接。
CHK2 kinase is a key mediator in many cellular responses to genotoxic stresses including ionizing radiation and topoisomerase inhibitors. Upon ionizing radiation, CHK2 is activated by ATM kinase and regulates the S-phase and G1-S checkpoints, apoptosis, and DNA repair by phosphorylating downstream target proteins such as p53 and Brca1. In addition, CHK2 is thought to be a multi-organ cancer susceptibility gene. In this study, we used a tandem affinity purification strategy to identify proteins that interact with CHK2 kinase. CDK11p110 kinase, implicated in pre-mRNA splicing and transcription, was identified as a CHK2-interacting protein. CHK2 kinase phosphorylated CDK11p110 on serine 737 in vitro. Unexpectedly, CHK2 kinase constitutively phosphorylated CDK11p110 in a DNA damage-independent manner. At a molecular level, CDK11p110 phosphorylation was required for homodimerization without affecting its kinase activity. Overexpression of CHK2 promoted pre-mRNA splicing. Conversely, CHK2 depletion decreased endogenous splicing activity. Mutation of the phosphorylation site in CDK11p110 to alanine abrogated its splicing activating activity. These results provide the first evidence that CHK2 kinase promotes pre-mRNA splicing via phosphorylating CDK11p110.