Regulation of ATR substrate selection by Rad17-dependent loading of Rad9 complexes onto chromatin
Regulation of ATR substrate selection by Rad17-dependent loading of Rad9 complexes onto chromatin
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DOI：
10.1101/gad.950302
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发表时间：
2002-01-15
影响因子：
10.5
通讯作者：
Elledge, SJ
中科院分区：
文献类型：
--
作者：
Zou, L;Cortez, D;Elledge, SJ
细胞通过激活控制细胞周期进程和 DNA 修复的信号通路网络来响应 DNA 损伤。酵母基因研究表明，几种检查点蛋白，包括 RFC 相关的 Rad17 蛋白和 PCNA 相关的 Rad1-Rad9-Hus1 蛋白复合物可能充当 DNA 损伤的传感器。在这项研究中，我们证明人类 Rad17 蛋白在损伤后将 Rad9 蛋白复合物募集到染色质上。 Rad17 在损伤前与染色质结合并被磷酸化；损伤后染色质上的 ATR，但 Rad9 加载到染色质上不需要 Rad17 的磷酸化。 Rad17 和 ATR 的染色质关联在很大程度上是独立的，这表明它们独立地定位于 DNA 损伤。此外，Rad17 的磷酸化需要 Hus1，这表明 Rad17 招募的 Rad1-Rad9-Hus1 复合物使 ATR 能够识别其底物。我们的数据与多个检查点蛋白复合物独立定位于 DNA 损伤位点并相互作用以触发检查点信号级联的模型一致。
Cells respond to DNA damage by activating a network of signaling pathways that control cell cycle progression and DNA repair. Genetic studies in yeast suggested that several checkpoint proteins, including the RFC-related Rad17 protein, and the PCNA-related Rad1-Rad9-Hus1 protein complex might function as sensors of DNA damage. In this study, we show that the human Rad17 protein recruits the Rad9 protein complex onto chromatin after damage. Rad17 binds to chromatin prior to damage and is phosphorylated by; ATR on chromatin after damage but Rad17's phosphorylation is not required for Rad9 loading onto chromatin. The chromatin associations of Rad17 and ATR are largely independent, which suggests that they localize to DNA damage independently. Furthermore, the phosphorylation of Rad17 requires Hus1, suggesting that the Rad1-Rad9-Hus1 complex recruited by Rad17 enables ATR to recognize its substrates. Our data are consistent with a model in which multiple checkpoint protein complexes localize to sites of DNA damage independently and interact to trigger the checkpoint-signaling cascade.