Mitochondrial antiviral signaling platform protein (MAVS) acts as a central hub for RIG-I receptor proximal signal propagation. However, key components in the assembly of the MAVS mitochondrial platform that promote RIG-I mitochondrial localization and optimal activation are still largely undefined. Employing pooled RNAi and yeast two-hybrid screenings, we report that the mitochondrial adaptor protein tripartite motif (TRIM)14 provides a docking platform for the assembly of the mitochondrial signaling complex required for maximal activation of RIG-I-mediated signaling, consisting of WHIP and protein phosphatase PPP6C. Following viral infection, the ubiquitin-binding domain in WHIP bridges RIG-I with MAVS by binding to polyUb chains of RIG-I at lysine 164. The ATPase domain in WHIP contributes to stabilization of the RIG-I-dsRNA interaction. Moreover, phosphatase PPP6C is responsible for RIG-I dephosphorylation. Together, our findings define the WHIP-TRIM14-PPP6C mitochondrial signalosome required for RIG-I-mediated innate antiviral immunity.

线粒体抗病毒信号平台蛋白（MAVS）充当RIG-I受体近端信号传播的中心枢纽。但是，MAVS线粒体平台组装中促进RIG-I线粒体定位和最佳激活的关键组件仍然很大程度上不确定。利用汇集的RNAi和酵母双杂交筛选，我们报告说线粒体衔接蛋白三方基序（TRIM）14为最大激活RIG-I介导的信号线（包括WHIP）所需的线粒体信号传递复合体的组装提供了一个停靠平台和蛋白磷酸酶PPP6C。病毒感染后，WHIP中的泛素结合结构域通过与赖氨酸164处的RIG-1的多Ub链结合而将RIG-1与MAVS桥接。WHIP中的ATPase域有助于稳定RIG-I-dsRNA的相互作用。此外，磷酸酶PPP6C负责RIG-I的去磷酸化。总之，我们的发现定义了RIG-I介导的先天抗病毒免疫所需的WHIP-TRIM14-PPP6C线粒体信号体。