ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic stress responses
ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic stress responses
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DOI：
10.1038/35082110
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发表时间：
2001-06-21
期刊：
影响因子：
64.8
通讯作者：
Wang, XF
中科院分区：
文献类型：
--
作者：
Bao, SD;Tibbetts, RS;Wang, XF
基因毒性应激触发检查点的激活，从而延缓细胞周期进程，以便进行DNA修复(1)。对裂解酵母的研究表明，Rad检查点蛋白家族的成员，包括Rad17、Rad1、Rad9和Hus1，是激活DNA损伤和复制检查点(2-5)的关键早期反应元件。在这里，我们证明了人类Rad17同源物(HRad17)与检查点激酶、ATM和ATR之间的直接调控联系。用遗传毒性药物处理人类细胞可诱导依赖ATM/ATR的hRad17在Ser635和Ser645处的磷酸化。HRad17突变体(hRad17(AA))的过表达使DNA损伤诱导的G(2)检查点消失，并使人成纤维细胞对遗传毒性应激敏感。与野生型hRad17不同，hRad17(Aa)突变体与hRad1-hRad9-hHus1检查点复合体的一个组成部分hRad1没有电离辐射诱导的关联。这些发现表明，依赖于ATR/ATM的hRad17的磷酸化是DNA损伤细胞中检查点信号传递过程中的一个关键早期事件。
Genotoxic stress triggers the activation of checkpoints that delay cell-cycle progression to allow for DNA repair(1). Studies in fission yeast implicate members of the Rad family of checkpoint proteins, which includes Rad17, Rad1, Rad9 and Hus1, as key early-response elements during the activation of both the DNA damage and replication checkpoints(2-5). Here we demonstrate a direct regulatory linkage between the human Rad17 homologue (hRad17) and the checkpoint kinases, ATM and ATR. Treatment of human cells with genotoxic agents induced ATM/ATR-dependent phosphorylation of hRad17 at Ser 635 and Ser 645. Overexpression of a hRad17 mutant (hRad17(AA)) bearing Ala substitutions at both phosphorylation sites abrogated the DNA-damage-induced G(2) checkpoint, and sensitized human fibroblasts to genotoxic stress. In contrast to wild-type hRad17, the hRad17(AA) mutant showed no ionizing-radiation-inducible association with hRad1, a component of the hRad1-hRad9-hHus1 checkpoint complex. These findings demonstrate that ATR/ATM-dependent phosphorylation of hRad17 is a critical early event during checkpoint signalling in DNA-damaged cells.