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.

中文翻译：

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ATAD5 作为 Ub-PCNA 去泛素化的调控平台


增殖细胞核抗原 (PCNA) 的泛素化状态对于调节 DNA 损伤旁路至关重要。在解决分叉停滞问题后，PCNA 随后被去泛素化，但底层机制仍然未定义。我们发现 ATAD5 的 N 末端结构域 (ATAD5-N) 是 PCNA 卸载复合物的最大亚基，可作为 Ub-PCNA 去泛素化的支架。 ATAD5 通过不同的 DNA 结合和 PCNA 结合基序识别 DNA 负载的 Ub-PCNA。此外，ATAD5 与 UAF1-USP1 去泛素酶形成异三聚体复合物，促进 DNA 负载的 Ub-PCNA 去泛素化。 ATAD5 还通过特定的相互作用增强 USP7 和 USP11 的 Ub-PCNA 去泛素化。 ATAD5 促进 UAF1-USP1、USP7 和 USP11 对多聚 Ub-PCNA 的独特去泛素化过程。此外，缺乏 UAF1 结合的 ATAD5 突变体对 DNA 损伤剂的敏感性增加。我们的结果最终表明，ATAD5 和 USP 合作，在 Ub-PCNA 从 DNA 中释放之前有效地去泛素化，从而安全地停用 DNA 修复过程。