Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands.
Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, the Netherlands.
Nat Commun. 2024 Jun 12;15(1):5032. doi: 10.1038/s41467-024-49431-6.
Maintenance of genome integrity requires tight control of DNA damage response (DDR) signalling and repair, with phosphorylation and ubiquitination representing key elements. How these events are coordinated to achieve productive DNA repair remains elusive. Here we identify the ubiquitin-conjugating enzyme UBE2D3 as a regulator of ATM kinase-induced DDR that promotes non-homologous end-joining (NHEJ) at telomeres. UBE2D3 contributes to DDR-induced chromatin ubiquitination and recruitment of the NHEJ-promoting factor 53BP1, both mediated by RNF168 upon ATM activation. Additionally, UBE2D3 promotes NHEJ by limiting RNF168 accumulation and facilitating ATM-mediated phosphorylation of KAP1-S824. Mechanistically, defective KAP1-S824 phosphorylation and telomeric NHEJ upon UBE2D3-deficiency are linked to RNF168 hyperaccumulation and aberrant PP2A phosphatase activity. Together, our results identify UBE2D3 as a multi-level regulator of NHEJ that orchestrates ATM and RNF168 activities. Moreover, they reveal a negative regulatory circuit in the DDR that is constrained by UBE2D3 and consists of RNF168- and phosphatase-mediated restriction of KAP1 phosphorylation.
维持基因组完整性需要严格控制 DNA 损伤反应 (DDR) 信号和修复，其中磷酸化和泛素化是关键要素。这些事件如何协调以实现有效的 DNA 修复仍然难以捉摸。在这里，我们确定泛素连接酶 UBE2D3 是 ATM 激酶诱导的 DDR 的调节剂，它促进端粒处的非同源末端连接 (NHEJ)。UBE2D3 通过 RNF168 在 ATM 激活时促进 DDR 诱导的染色质泛素化和促进 NHEJ 的因子 53BP1 的募集，这两者均由 RNF168 介导。此外，UBE2D3 通过限制 RNF168 的积累和促进 ATM 介导的 KAP1-S824 磷酸化来促进 NHEJ。从机制上讲，UBE2D3 缺陷导致 KAP1-S824 磷酸化和端粒 NHEJ 缺陷与 RNF168 过度积累和异常的 PP2A 磷酸酶活性有关。总之，我们的研究结果确定了 UBE2D3 是 NHEJ 的多水平调节剂，它协调 ATM 和 RNF168 的活性。此外，它们揭示了 DDR 中的一个负反馈回路，该回路受到 UBE2D3 的限制，由 RNF168 和磷酸酶介导的 KAP1 磷酸化限制组成。
