Department of Radiation Toxicology and Oncology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, 100850, P. R. China.
Institute for Environmental Medicine and Radiation Hygiene, School of Public Health, University of South China, Hengyang, Hunan Province, 421001, P. R. China.
Cell Death Dis. 2020 May 26;11(5):400. doi: 10.1038/s41419-020-2611-0.
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is the core component of DNA-PK complex in the non-homologous end-joining (NHEJ) repair of DNA double-strand breaks, and its activity is strictly controlled by DNA-PKcs phosphorylation. The ubiquitin-like protein, NEDD8 is involved in regulation of DNA damage response, but it remains mysterious whether and how NEDD8-related neddylation affects DNA-PKcs and the NHEJ process. Here, we show that DNA-PKcs is poly-neddylated at its kinase domain. The neddylation E2-conjugating enzyme UBE2M and E3 ligase HUWE1 (HECT, UBA, and WWE domain containing E3 ubiquitin protein ligase 1) are responsible for the DNA-PKcs neddylation. Moreover, inhibition of HUWE1-dependent DNA-PKcs neddylation impairs DNA-PKcs autophosphorylation at Ser2056. Finally, depletion of HUWE1-dependent DNA-PKcs neddylation reduces the efficiency of NHEJ. These studies provide insights how neddylation modulates the activity of NHEJ core complex.
DNA 依赖性蛋白激酶催化亚基（DNA-PKcs）是 DNA 双链断裂非同源末端连接（NHEJ）修复中 DNA-PK 复合物的核心组成部分，其活性受到 DNA-PKcs 磷酸化的严格调控。泛素样蛋白 NEDD8 参与 DNA 损伤反应的调节，但 NEDD8 相关的 neddylation 是否以及如何影响 DNA-PKcs 和 NHEJ 过程仍然神秘。在这里，我们表明 DNA-PKcs 在其激酶结构域上发生多聚 neddylation。NEDD8 的 E2 连接酶 UBE2M 和 E3 连接酶 HUWE1（HECT、UBA 和 WWE 结构域包含 E3 泛素蛋白连接酶 1）负责 DNA-PKcs 的 neddylation。此外，抑制 HUWE1 依赖性 DNA-PKcs neddylation 会损害 DNA-PKcs 在 Ser2056 处的自磷酸化。最后，HUWE1 依赖性 DNA-PKcs neddylation 的耗竭会降低 NHEJ 的效率。这些研究提供了关于 neddylation 如何调节 NHEJ 核心复合物活性的见解。
