Role of human Cds1 (Chk2) kinase in DNA damage checkpoint and its regulation by p53
Role of human Cds1 (Chk2) kinase in DNA damage checkpoint and its regulation by p53
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DOI：
10.1074/jbc.274.44.31463
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发表时间：
1999-10-29
影响因子：
4.8
通讯作者：
Nakanishi, M
中科院分区：
文献类型：
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作者：
Tominaga, K;Morisaki, H;Nakanishi, M
为了应对 DNA 损伤，哺乳动物细胞通过 p53 的磷酸化和稳定化来采用检查点调节，以延迟细胞周期进程。然而，大多数缺乏功能性p53的癌细胞保留了未知的检查点机制，通过该机制细胞被阻滞在G(2)/M期。在这里，我们证明，不仅在正常细胞中，而且在缺乏功能性 p53 的癌细胞中，Cds1/Rad53 激酶 (hCds1) 的人类同源物会因 DNA 损伤而快速磷酸化和激活。对多种癌细胞系的调查表明，hCds1 mRNA 的表达水平与功能性 p53 的存在呈负相关。此外，用SV40 T抗原或人乳头瘤病毒E6或E7转染正常人成纤维细胞会导致hCds1 mRNA的显着诱导，并且将功能性p53引入SV40 T抗原和E6转染细胞（而非E7转染细胞）会降低hCds1水平，表明p53负向调节hCds1的表达。在没有功能性共济失调毛细血管扩张突变 (ATM) 蛋白的细胞中，观察到 hCds1 的磷酸化和激活是对紫外线（而非电离辐射）诱导的 DNA 损伤的反应。这些结果表明 hCds1 通过 ATM 依赖性和非依赖性途径被激活，并且它可能补充哺乳动物细胞 DNA 损伤检查点中 p53 的功能。
In response to DNA damage, mammalian cells adopt checkpoint regulation, by phosphorylation and stabilization of p53, to delay cell cycle progression. However, most cancer cells that lack functional p53 retain an unknown checkpoint mechanism(s) by which cells are arrested at the G(2)/M phase. Here we demonstrate that a human homolog of Cds1/Rad53 kinase (hCds1) is rapidly phosphorylated and activated in response to DNA damage not only in normal cells but in cancer cells lacking functional p53. A survey of various cancer cell lines revealed that the expression level of hCds1 mRNA is inversely related to the presence of functional p53. In addition, transfection of normal human fibroblasts with SV40 T antigen or human papilloma viruses E6 or E7 causes a marked induction of hCds1 mRNA, and the introduction of functional p53 into SV40 T antigen- and E6-, but not E7-, transfected cells decreases the hCds1 level, suggesting that p53 negatively regulates the expression of hCds1. In cells without functional ataxia telangiectasia mutated (ATM) protein, phosphorylation and activation of hCds1 were observed in response to DNA damage induced by UV but not by ionizing irradiation. These results suggest that hCds1 is activated through an ATM-dependent as well as -independent pathway and that it may complement the function of p53 in DNA damage checkpoints in mammalian cells.