TOPBP1 regulates RAD51 phosphorylation and chromatin loading and determines PARP inhibitor sensitivity.
TOPBP1 regulates RAD51 phosphorylation and chromatin loading and determines PARP inhibitor sensitivity.
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DOI：
10.1083/jcb.201507042
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发表时间：
2016-02-01
期刊：
影响因子：
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通讯作者：
Bartek J
中科院分区：
文献类型：
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作者：
Moudry P;Watanabe K;Wolanin KM;Bartkova J;Wassing IE;Watanabe S;Strauss R;Troelsgaard Pedersen R;Oestergaard VH;Lisby M;Andújar-Sánchez M;Maya-Mendoza A;Esashi F;Lukas J;Bartek J
TOPBP 1在同源重组修复中起作用，影响对化疗剂奥拉帕尼的反应，并在人卵巢癌亚群中表现出异常模式。拓扑异构酶IIβ结合蛋白1（Topoisomerase IIβ-binding protein 1，TOPBP 1）参与DNA复制和DNA损伤反应，但其在DNA修复中的作用及其与人类肿瘤的关系尚不清楚。在这里，通过无偏见的小干扰RNA筛选，我们确定并验证了TOPBP 1作为一种新的决定因素，其损失使人类细胞对olaparib（一种聚（ADP-核糖）聚合酶抑制剂）敏感。我们发现TOPBP 1在同源重组（HR）修复中起作用，影响奥拉帕尼反应，并在人类卵巢癌亚群中表现出异常模式。TOPBP 1耗竭废除了RAD 51加载到染色质和RAD 51灶的形成，但不影响DNA末端切除和RPA加载的上游HR步骤。此外，TOPBP 1 BRCT结构域7/8对于RAD 51灶形成是必需的。在机制上，TOPBP 1物理结合PLK 1，并促进PLK 1激酶介导的RAD 51在丝氨酸14处的磷酸化，这是RAD 51募集到染色质所需的修饰。总的来说，我们的研究结果为TOPBP 1在HR中的作用提供了机制性见解，对癌症治疗具有潜在的临床意义。
TOPBP1 acts in homologous recombination repair, impacts the response to chemotherapeutic agent olaparib, and exhibits aberrant patterns in subsets of human ovarian carcinomas. Topoisomerase IIβ-binding protein 1 (TOPBP1) participates in DNA replication and DNA damage response; however, its role in DNA repair and relevance for human cancer remain unclear. Here, through an unbiased small interfering RNA screen, we identified and validated TOPBP1 as a novel determinant whose loss sensitized human cells to olaparib, an inhibitor of poly(ADP-ribose) polymerase. We show that TOPBP1 acts in homologous recombination (HR) repair, impacts olaparib response, and exhibits aberrant patterns in subsets of human ovarian carcinomas. TOPBP1 depletion abrogated RAD51 loading to chromatin and formation of RAD51 foci, but without affecting the upstream HR steps of DNA end resection and RPA loading. Furthermore, TOPBP1 BRCT domains 7/8 are essential for RAD51 foci formation. Mechanistically, TOPBP1 physically binds PLK1 and promotes PLK1 kinase–mediated phosphorylation of RAD51 at serine 14, a modification required for RAD51 recruitment to chromatin. Overall, our results provide mechanistic insights into TOPBP1’s role in HR, with potential clinical implications for cancer treatment.