Rad17 phosphorylation is required for claspin recruitment and Chk1 activation in response to replication stress
Rad17 phosphorylation is required for claspin recruitment and Chk1 activation in response to replication stress
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DOI：
10.1016/j.molcel.2006.06.022
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发表时间：
2006-08-04
期刊：
影响因子：
16
通讯作者：
Li, Lei
中科院分区：
文献类型：
--
作者：
Wang, Xin;Zou, Lee;Li, Lei
atr介导的检查点不仅对基因毒性应激反应至关重要，而且对细胞增殖也至关重要。rfc相关的检查点蛋白Rad17是ATR的磷酸化底物，对ATR介导的检查点信号传导和细胞存活至关重要。在这里，我们发现ATR对Rad17的磷酸化对基因组稳定性和S期抑制很重要，但对细胞存活不是必需的。磷化体Rad17AA在羟基脲（HU）和紫外线（UV）诱导的Chk1激活中表现出明显的缺陷，表明不同类型的复制干扰需要不同的Rad17功能。虽然表达Rad17AA的细胞可以在HU治疗后启动Chk1磷酸化，但它们在HU停药后不能维持Chk1磷酸化，并且对HU非常敏感。重要的是，我们发现磷酸化的Rad17与Claspin相互作用并调节其磷酸化。这些发现揭示了Rad17在ATR-Rad17-Claspin-Chk1信号级联中磷酸化依赖的功能，该信号级联响应特定的复制应激。
The ATR-mediated checkpoint is not only critical for responding to genotoxic stress but also essential for cell proliferation. The RFC-related checkpoint protein Rad17, a phosphorylation substrate of ATR, is critical for ATR-mediated checkpoint signaling and cell survival. Here, we show that phosphorylation of Rad17 by ATR is important for genomic stability and restraint of S phase but is not essential for cell survival. The phosphomutant Rad17AA exhibits distinct defects in hydroxyurea- (HU) and ultraviolet-(UV) induced Chk1 activation, indicating that separate Rad17 functions are required differently in response to different types of replication interference. Although cells expressing Rad17AA can initiate Chk1 phosphorylation after HU treatment, they fail to sustain Chk1 phosphorylation after withdrawal of HU and are profoundly sensitive to HU. Importantly, we found that phosphorylated Rad17 interacts with Claspin and regulates its phosphorylation. These findings reveal a phosphorylation-dependent function of Rad17 in an ATR-Rad17-Claspin-Chk1 -signaling cascade that responds to specific replication stress.