Key Laboratory of Infection and Immunity of Shandong Province & Key Laboratory for Experimental Teratology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, P.R. China.
Department of Immunology, School of Biomedical Sciences, Shandong University, Jinan, 250012, Shandong, P.R. China.
Cell Mol Immunol. 2023 Oct;20(10):1186-1202. doi: 10.1038/s41423-023-01065-2. Epub 2023 Aug 15.
The adaptor molecule MAVS forms prion-like aggregates to govern the RIG-I-like receptor (RLR) signaling cascade. Lys63 (K63)-linked polyubiquitination is critical for MAVS aggregation, yet the underlying mechanism and the corresponding E3 ligases and deubiquitinating enzymes (DUBs) remain elusive. Here, we found that the K63-linked polyubiquitin chains loaded on MAVS can be directly recognized by RIG-I to initiate RIG-I-mediated MAVS aggregation with the prerequisite of the CARD-CARD interaction. Interestingly, many K63-linked polyubiquitin chains attach to MAVS via an unanchored linkage. We identified Ube2N as a major ubiquitin-conjugating enzyme for MAVS and revealed that Ube2N cooperates with the E3 ligase Riplet and TRIM31 to promote the unanchored K63-linked polyubiquitination of MAVS. In addition, we identified USP10 as a direct DUB that removes unanchored K63-linked polyubiquitin chains from MAVS. Consistently, USP10 attenuates RIG-I-mediated MAVS aggregation and the production of type I interferon. Mice with a deficiency in USP10 show more potent resistance to RNA virus infection. Our work proposes a previously unknown mechanism for the activation of the RLR signaling cascade triggered by MAVS-attached unanchored K63-linked polyubiquitin chains and establishes the DUB USP10 and the E2:E3 pair Ube2N-Riplet/TRIM31 as a specific regulatory system for the unanchored K63-linked ubiquitination and aggregation of MAVS upon viral infection.
接头分子 MAVS 形成类朊病毒聚集物以控制 RIG-I 样受体 (RLR) 信号级联。K63（K63）连接的多泛素化对于 MAVS 聚集至关重要，但潜在机制以及相应的 E3 连接酶和去泛素化酶 (DUB) 仍然难以捉摸。在这里，我们发现加载在 MAVS 上的 K63 连接的多泛素链可以被 RIG-I 直接识别，从而在 CARD-CARD 相互作用的前提下启动 RIG-I 介导的 MAVS 聚集。有趣的是，许多 K63 连接的多泛素链通过无锚连接附着在 MAVS 上。我们鉴定了 Ube2N 作为 MAVS 的主要泛素连接酶，并揭示了 Ube2N 与 E3 连接酶 Riplet 和 TRIM31 合作促进 MAVS 的无锚 K63 连接的多泛素化。此外，我们鉴定了 USP10 作为一种直接的 DUB，可从 MAVS 上去除无锚 K63 连接的多泛素链。一致地，USP10 减弱了 RIG-I 介导的 MAVS 聚集和 I 型干扰素的产生。USP10 缺陷的小鼠对 RNA 病毒感染表现出更强的抵抗力。我们的工作提出了一个以前未知的机制，用于由 MAVS 附着的无锚 K63 连接的多泛素链触发的 RLR 信号级联的激活，并建立了 DUB USP10 和 E2:E3 对 Ube2N-Riplet/TRIM31，作为病毒感染时 MAVS 无锚 K63 连接泛素化和聚集的特定调节系统。
