Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea.
Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
Proc Natl Acad Sci U S A. 2024 Aug 20;121(34):e2315759121. doi: 10.1073/pnas.2315759121. Epub 2024 Aug 15.
Ubiquitination status of proliferating cell nuclear antigen (PCNA) is crucial for regulating DNA lesion bypass. After the resolution of fork stalling, PCNA is subsequently deubiquitinated, but the underlying mechanism remains undefined. We found that the N-terminal domain of ATAD5 (ATAD5-N), the largest subunit of the PCNA-unloading complex, functions as a scaffold for Ub-PCNA deubiquitination. ATAD5 recognizes DNA-loaded Ub-PCNA through distinct DNA-binding and PCNA-binding motifs. Furthermore, ATAD5 forms a heterotrimeric complex with UAF1-USP1 deubiquitinase, facilitating the deubiquitination of DNA-loaded Ub-PCNA. ATAD5 also enhances the Ub-PCNA deubiquitination by USP7 and USP11 through specific interactions. ATAD5 promotes the distinct deubiquitination process of UAF1-USP1, USP7, and USP11 for poly-Ub-PCNA. Additionally, ATAD5 mutants deficient in UAF1-binding had increased sensitivity to DNA-damaging agents. Our results ultimately reveal that ATAD5 and USPs cooperate to efficiently deubiquitinate Ub-PCNA prior to its release from the DNA in order to safely deactivate the DNA repair process.
泛素化状态的增殖细胞核抗原（PCNA）对于调节 DNA 损伤旁路至关重要。在解决叉停顿后，PCNA 随后被去泛素化，但潜在的机制仍未定义。我们发现，PCNA 卸载复合物的最大亚基 ATAD5 的 N 端结构域（ATAD5-N）作为 Ub-PCNA 去泛素化的支架发挥作用。ATAD5 通过独特的 DNA 结合和 PCNA 结合基序识别负载 DNA 的 Ub-PCNA。此外，ATAD5 与 UAF1-USP1 去泛素化酶形成异源三聚体复合物，促进负载 DNA 的 Ub-PCNA 的去泛素化。ATAD5 还通过特异性相互作用增强了 USP7 和 USP11 对多 Ub-PCNA 的去泛素化作用。ATAD5 促进 UAF1-USP1、USP7 和 USP11 对多 Ub-PCNA 的去泛素化过程。此外，缺乏与 UAF1 结合的 ATAD5 突变体对 DNA 损伤剂更敏感。我们的研究结果最终揭示了 ATAD5 和 USPs 合作，在 PCNA 从 DNA 上释放之前，有效地对 Ub-PCNA 进行去泛素化，以安全地使 DNA 修复过程失活。
