Poly(ADP-ribose) polymerase 1 (PARP1) is a DNA damage sensor, which upon activation, recruits downstream proteins by poly(ADP-ribosyl)ation (PARylation). However, it remains largely unclear how PARP1 activity is regulated. Interestingly, the data obtained through this study revealed that PARP1 was co-immunoprecipitated with checkpoint kinase 2 (CHK2), and the interaction was increased after oxidative DNA damage. Moreover, CHK2 depletion resulted in a reduction in overall PARylation. To further explore the functional relationship between PARP1 and CHK2, this study employed H₂O₂ to induce an oxidative DNA damage response in cells. Here, we showed that CHK2 and PARP1 interact in vitro and in vivo through the CHK2 SCD domain and the PARP1 BRCT domain. Furthermore, CHK2 stimulates the PARylation activity of PARP1 through CHK2-dependent phosphorylation. Consequently, the impaired repair associated with PARP1 depletion could be rescued by re-expression of wild-type PARP1 and the phospho-mimic but not the phospho-deficient mutant. Mechanistically, we showed that CHK2-dependent phosphorylation of PARP1 not only regulates its cellular localization but also promotes its catalytic activity and its interaction with XRCC1. These findings indicate that CHK2 exerts a multifaceted impact on PARP1 in response to oxidative stress to facilitate DNA repair and to maintain cell survival.

中文翻译：

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CHK2介导的PARP1在氧化DNA损伤反应中的调节。

聚 (ADP-核糖) 聚合酶 1 (PARP1) 是一种 DNA 损伤传感器，它在激活后通过聚 (ADP-核糖) 化 (PARylation) 募集下游蛋白质。然而，目前尚不清楚如何调节 PARP1 活性。有趣的是，通过这项研究获得的数据显示，PARP1 与检查点激酶 2 (CHK2) 共免疫沉淀，并且在 DNA 氧化损伤后相互作用增加。此外，CHK2 消耗导致整体 PARylation 减少。为了进一步探索 PARP1 和 CHK2 之间的功能关系，本研究采用 H ₂ O ₂诱导细胞中的氧化性 DNA 损伤反应。在这里，我们展示了 CHK2 和 PARP1 通过 CHK2 SCD 结构域和 PARP1 BRCT 结构域在体外和体内相互作用。此外，CHK2 通过 CHK2 依赖性磷酸化刺激 PARP1 的 PARylation 活性。因此，与 PARP1 耗竭相关的受损修复可以通过重新表达野生型 PARP1 和磷酸模拟物而不是磷酸缺陷突变体来挽救。从机制上讲，我们发现 PARP1 的 CHK2 依赖性磷酸化不仅调节其细胞定位，而且促进其催化活性及其与 XRCC1 的相互作用。这些发现表明 CHK2 对 PARP1 产生多方面的影响，以响应氧化应激以促进 DNA 修复和维持细胞存活。