Cdk1 Protein-mediated Phosphorylation of Receptor-associated Protein 80 (RAP80) Serine 677 Modulates DNA Damage-induced G2/M Checkpoint and Cell Survival
Cdk1 Protein-mediated Phosphorylation of Receptor-associated Protein 80 (RAP80) Serine 677 Modulates DNA Damage-induced G2/M Checkpoint and Cell Survival
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DOI：
10.1074/jbc.m112.401299
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发表时间：
2013-02-08
影响因子：
4.8
通讯作者：
Kim, Hongtae
中科院分区：
文献类型：
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作者：
Cho, Hyun Jung;Oh, Yun Jung;Kim, Hongtae
翻译后磷酸化在DNA损伤反应途径中的信号和修复蛋白的组装中起关键作用。RAP 80是BRCA 1-A复合物的一个组成部分，在细胞周期检查点激活和DNA损伤修复中至关重要。然而，其分子机制尚不清楚。在这项研究中，我们确定Cdk 1作为一个新的RAP 80结合蛋白，并证明Cdk 1-细胞周期蛋白B-1复合物磷酸化RAP 80在Ser-677使用体外激酶测定和磷酸肽特异性抗体磷酸化-Ser-677的RAP 80。RAP 80 Ser-677磷酸化发生在细胞周期的M期，当Cdk 1处于激活状态时。此外，电离辐射（IR）诱导RAP 80磷酸化Ser-677。Ser-677突变为丙氨酸使细胞对IR敏感，并在G（2）/M检查点控制中起作用。这些结果表明，由Cdk 1-cyclin B-1复合物引起的RAP 80的翻译后磷酸化对于RAP 80对IR和G（2）/M检查点控制的功能敏感性是重要的。
Post-translational phosphorylation plays critical roles in the assembly of signaling and repair proteins in the DNA damage response pathway. RAP80, a component of the BRCA1-A complex, is crucial in cell cycle checkpoint activation and DNA damage repair. However, its molecular mechanism is unclear. In this study, we identified Cdk1 as a new RAP80-binding protein and demonstrated that the Cdk1-cyclin B-1 complex phosphorylates RAP80 at Ser-677 using an in vitro kinase assay and a phosphopeptide-specific antibody against phospho-Ser-677 of RAP80. RAP80 Ser-677 phosphorylation occurred in the M phase of the cell cycle when Cdk1 was in an active state. In addition, ionizing radiation (IR) induced RAP80 phosphorylation at Ser-677. Mutation of Ser-677 to alanine sensitized cells to IR and functioned in G(2)/M checkpoint control. These results suggest that post-translational phosphorylation of RAP80 by the Cdk1-cyclin B-1 complex is important for RAP80 functional sensitivity to IR and G(2)/M checkpoint control.