DDB1 targets Chk1 to the Cul4 E3 ligase complex in normal cycling cells and in cells experiencing replication stress.
DDB1 targets Chk1 to the Cul4 E3 ligase complex in normal cycling cells and in cells experiencing replication stress.
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DOI：
10.1158/0008-5472.can-08-3382
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发表时间：
2009-03-15
期刊：
影响因子：
11.2
通讯作者：
Piwnica-Worms H
中科院分区：
文献类型：
--
作者：
Leung-Pineda V;Huh J;Piwnica-Worms H
Chk 1蛋白激酶在正常增殖细胞和经历复制和遗传毒性应激的细胞中保持基因组完整性。Chk 1目前在抗癌方案中被靶向。在这里，我们确定受损的DNA结合蛋白1（DDB 1）作为一种新的Chk 1相互作用蛋白。DDB 1是E3连接酶复合物的一部分，该复合物包括cullin蛋白Cul 4A和4 B。我们报告Cul 4A/DDB 1负调控Chk 1在体内的稳定性。Chk 1与Cul 4A/DDB 1在未受干扰的细胞分裂周期和Chk 1磷酸化和复制应激增强这些相互作用。Cul 4A/DDB 1在体内调节Chk 1的泛素化，而Chk 1在体外以Cul 4A/DDB 1依赖的方式直接被泛素化。此外，Chk 1在Cul 4A/DDB 1缺陷的细胞中稳定。这项研究表明，Chk 1丰度的调节Cul 4A/DDB 1泛素连接酶在未受干扰的细胞分裂周期，在复制应激和HSP 90抑制后，Chk 1/Cul 4A/DDB 1途径的失调干扰IR诱导的G2检查点。
The Chk1 protein kinase preserves genome integrity in normal proliferating cells and in cells experiencing replicative- and genotoxic-stress. Chk1 is currently being targeted in anti-cancer regimens. Here we identify damaged DNA-binding protein 1 (DDB1) as a novel Chk1 interacting protein. DDB1 is part of an E3 ligase complex that includes the cullin proteins, Cul4A and 4B. We report that Cul4A/DDB1 negatively regulates Chk1 stability in vivo. Chk1 associates with Cul4A/DDB1 during an unperturbed cell division cycle and both Chk1 phosphorylation and replication-stress enhanced these interactions. Cul4A/DDB1 regulates Chk1 ubiquitination in vivo and Chk1 is directly ubiquitinated in vitro in a Cul4A/DDB1-dependent manner. Furthermore, Chk1 is stabilized in cells deficient for Cul4A/DDB1. This study demonstrates that Chk1 abundance is regulated by the Cul4A/DDB1 ubiquitin ligase during an unperturbed cell division cycle, in response to replicative stress and upon HSP90 inhibition and that deregulation of the Chk1/Cul4A/DDB1 pathway perturbs the IR-induced G2 checkpoint.