Department of Rheumatology and Immunology, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China.
Department of Virology, College of Life Sciences, Department of Immunology, Medical Research Institute, Wuhan University, Wuhan, 430072, China.
Cell Mol Immunol. 2021 Aug;18(8):1981-1994. doi: 10.1038/s41423-020-00564-w. Epub 2020 Nov 12.
Activation of the TAK1 signalosome is crucial for mediating the innate immune response to pathogen invasion and is regulated by multiple layers of posttranslational modifications, including ubiquitination, SUMOylation, and phosphorylation; however, the underlying molecular mechanism is not fully understood. In this study, TRIM60 negatively regulated the formation and activation of the TAK1 signalosome. Deficiency of TRIM60 in macrophages led to enhanced MAPK and NF-κB activation, accompanied by elevated levels of proinflammatory cytokines but not IFN-I. Immunoprecipitation-mass spectrometry assays identified TAB2 as the target of TRIM60 for SUMOylation rather than ubiquitination, resulting in impaired formation of the TRAF6/TAB2/TAK1 complex and downstream MAPK and NF-κB pathways. The SUMOylation sites of TAB2 mediated by TRIM60 were identified as K329 and K562; substitution of these lysines with arginines abolished the SUMOylation of TAB2. In vivo experiments showed that TRIM60-deficient mice showed an elevated immune response to LPS-induced septic shock and L. monocytogenes infection. Our data reveal that SUMOylation of TAB2 mediated by TRIM60 is a novel mechanism for regulating the innate immune response, potentially paving the way for a new strategy to control antibacterial immune responses.
TAK1 信号小体的激活对于介导病原体入侵的先天免疫反应至关重要，并且受到多种翻译后修饰的调控，包括泛素化、SUMO 化和磷酸化；然而，其潜在的分子机制尚不完全清楚。在这项研究中，TRIM60 负调控 TAK1 信号小体的形成和激活。巨噬细胞中 TRIM60 的缺失导致 MAPK 和 NF-κB 的激活增强，伴随着促炎细胞因子而非 IFN-I 的水平升高。免疫沉淀-质谱分析鉴定 TAB2 为 TRIM60 的 SUMO 化而不是泛素化的靶标，导致 TRAF6/TAB2/TAK1 复合物以及下游 MAPK 和 NF-κB 途径的形成受损。TRIM60 介导的 TAB2 的 SUMO 化位点被鉴定为 K329 和 K562；用精氨酸取代这些赖氨酸可使 TAB2 的 SUMO 化失活。体内实验表明，TRIM60 缺失的小鼠对 LPS 诱导的败血症休克和单核细胞增生李斯特菌感染的免疫反应增强。我们的数据表明，TRIM60 介导的 TAB2 的 SUMO 化是调节先天免疫反应的一种新机制，可能为控制抗菌免疫反应开辟了新的策略。
