PCNA-dependent regulation of p21 ubiquitylation and degradation via the CRL4Cdt2 ubiquitin ligase complex
PCNA-dependent regulation of p21 ubiquitylation and degradation via the CRL4Cdt2 ubiquitin ligase complex
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DOI：
10.1101/gad.1676108
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发表时间：
2008-09-15
影响因子：
10.5
通讯作者：
Dutta, Anindya
中科院分区：
文献类型：
--
作者：
Abbas, Tarek;Sivaprasad, Uma;Dutta, Anindya
DNA聚合酶δ持续合成能力因子修饰细胞核抗原（PCNA）通过CRL 4（Cdt 2）E3泛素连接酶复合物促进DNA损伤诱导的复制起始因子Cdt 1的降解。在这里，我们证明，PCNA促进泛素化和降解的CDK抑制剂p21在细胞照射低剂量的紫外线（UV）通过类似的机制。缺乏Cu 14、DDB 1（损伤特异性DNA结合蛋白-1）或DCAF Cdt 2的人类细胞缺乏UV诱导的p21泛素化和降解。通过siRNA或p21中的突变消除PCNA结合的哺乳动物细胞的PCNA耗竭，防止UV诱导的p21泛素化和降解，表明与PCNA的物理结合对于通过CRL 4（Cdt 2）泛素连接酶的p21的有效泛素化是必需的。Cdt 2作为p21的底物募集因子作用于CRL 4泛素连接酶复合物的其余部分。CRL 4（Cdt 2）E3泛素连接酶在体内和体外均使p21泛素化，其活性依赖于p21与PCNA的相互作用。最后，我们表明，CRL 4（Cdt 2）和SCFSkp 2泛素连接酶是冗余的，彼此在促进p21的降解在一个不受干扰的细胞周期的S期。
The DNA polymerase delta processivity factor Proliferating Cell Nuclear Antigen (PCNA) promotes the DNA damage-induced degradation of the replication initiation factor Cdt1 via the CRL4(Cdt2) E3 ubiquitin ligase complex. Here we demonstrate that PCNA promotes the ubiquitylation and degradation of the CDK inhibitor p21 in cells irradiated with low dose of ultraviolet (UV) by a similar mechanism. Human cells that are depleted of Cu14, DDB1 (damage-specific DNA-binding protein-1), or the DCAF Cdt2, are deficient in the UV-induced ubiquitylation and degradation of p21. Depletion of mammalian cells of PCNA by siRNA, or mutations in p21 that abrogate PCNA binding, prevent UV-induced p21 ubiquitylation and degradation, indicating that physical binding with PCNA is necessary for the efficient ubiquitylation of p21 via the CRL4(Cdt2) ubiquitin ligase. Cdt2 functions as the substrate recruiting factor for p21 to the rest of the CRL4 ubiquitin ligase complex. The CRL4(Cdt2) E3 ubiquitin ligase ubiquitylates p21 both in vivo and in vitro, and its activity is dependent on the interaction of p21 with PCNA. Finally, we show that the CRL4(Cdt2) and the SCFSkp2 ubiquitin ligases are redundant with each other in promoting the degradation of p21 during an unperturbed S phase of the cell cycle.