Li Yunlong, Wu Siqi, Tian Xuyang, Kong Chen, Hong Wenbin, Xiao Tianyichen, Wang Songqing, Wei Zhiming, Su Zhiming, Ren Haixia, Song Yunlong, Hu Lichen, Lin Donghai, Yao Hongwei, Han Jiahuai, Chen Xueqin, Lin Tianwei
State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Xiamen University, Xiamen, Fujian, China; Cancer Research Center of Xiamen University, Xiamen, Fujian, China.
State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China.
J Biol Chem. 2025 Apr;301(4):108367. doi: 10.1016/j.jbc.2025.108367. Epub 2025 Feb 28.
TRIM25, an E3 ligase, is an important regulator to modulate the functions of retinoic acid inducible gene-I (RIG-I) and other factors in innate immunity. Herein the structural interaction between the 2CARD domain of RIG-I and the PRYSPRY domain of TRIM25 was investigated by NMR, X-ray crystallography, computer-assisted modeling, and cell-based assays to elucidate the complex structure of PRYSPRY/2CARD. The interacting model indicated that docking of 2CARD onto PRYSPRY brought two RIG-I molecules into a close proximity to form a dimer. The attachment of a short ubiquitin chain covalently by the TRIM25's E3 ligase activity was favorable for tethering a neighboring RIG-I dimer to form the tetrameric RIG-I by noncovalent interactions. The data supported the notion that the TRIM25-RIG-I interaction was important to activate the RIG-I pathway to suppress the replication of RNA viruses, such as vesicular stomatitis virus. This work provides a structural rationale to delineate the underlying mechanism of TRIM25 regulation of RIG-I.
TRIM25是一种E3连接酶，是调节视黄酸诱导基因I（RIG-I）功能以及先天免疫中其他因子的重要调节因子。在此，通过核磁共振、X射线晶体学、计算机辅助建模和基于细胞的实验，研究了RIG-I的2CARD结构域与TRIM25的PRYSPRY结构域之间的结构相互作用，以阐明PRYSPRY/2CARD的复杂结构。相互作用模型表明，2CARD与PRYSPRY对接使两个RIG-I分子紧密靠近形成二聚体。TRIM25的E3连接酶活性共价连接一条短泛素链，有利于通过非共价相互作用将相邻的RIG-I二聚体连接起来形成四聚体RIG-I。这些数据支持了这样一种观点，即TRIM25与RIG-I的相互作用对于激活RIG-I途径以抑制RNA病毒（如水泡性口炎病毒）的复制很重要。这项工作为阐明TRIM25对RIG-I调控的潜在机制提供了结构依据。
