Bist Pradeep, Kim Susana Soo-Yeon, Pulloor Niyas Kudukil, McCaffrey Kathleen, Nair Sajith Kumar, Liu Yiliu, Lin Rongtuan, Krishnan Manoj N
Program on Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore, Singapore.
Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Canada.
Mol Cell Biol. 2017 Mar 1;37(6). doi: 10.1128/MCB.00537-16. Print 2017 Mar 15.
Transcription of type I interferon genes during RNA virus infection requires signal communication between several pattern recognition receptor (PRR)-adaptor complexes located at distinct subcellular membranous compartments and a central cytoplasmic TBK1-interferon regulatory factor 3 (IRF3) kinase-transcription factor module. However, how the cell integrates signal transduction through spatially distinct modules of antiviral signaling pathways is less defined. RIG-I is a major cytosolic PRR involved in the control of several RNA viruses. Here we identify ArfGAP domain-containing protein 2 (ADAP2) as a key novel scaffolding protein that integrates different modules of the RIG-I pathway, located at distinct subcellular locations, and mediates cellular antiviral type I interferon production. ADAP2 served to bridge the mitochondrial membrane-bound upstream RIG-I adaptor MAVS and the downstream cytosolic complex of NEMO (regulatory subunit of TBK1), TBK1, and IRF3, leading to IRF3 phosphorylation. Furthermore, independently, ADAP2 also functioned as a major orchestrator of the interaction of TBK1 with NEMO and IRF3. Mutational and cell-free reconstituted RIG-I signaling assay-based analyses identified that the ArfGAP domain of ADAP2 mediates the interferon response. TRAF3 acted as a trigger for ADAP2 to recruit RIG-I pathway component proteins into a single macromolecular complex. This study provides important novel insights into the assembly and integration of different modules of antiviral signaling cascades.
RNA病毒感染期间I型干扰素基因的转录需要位于不同亚细胞膜性区室的几种模式识别受体（PRR）-衔接蛋白复合物与细胞质中的核心TBK1-干扰素调节因子3（IRF3）激酶-转录因子模块之间进行信号传导。然而，细胞如何通过空间上不同的抗病毒信号通路模块整合信号转导尚不清楚。RIG-I是一种主要的胞质PRR，参与多种RNA病毒的控制。在此，我们鉴定出含ArfGAP结构域蛋白2（ADAP2）是一种关键的新型支架蛋白，它整合了位于不同亚细胞位置的RIG-I通路的不同模块，并介导细胞抗病毒I型干扰素的产生。ADAP2用于连接线粒体膜结合的上游RIG-I衔接蛋白MAVS与下游的NEMO（TBK1的调节亚基）、TBK1和IRF3的胞质复合物，导致IRF3磷酸化。此外，ADAP2还独立地作为TBK1与NEMO和IRF3相互作用的主要协调者。基于突变和无细胞重构的RIG-I信号转导分析表明，ADAP2的ArfGAP结构域介导干扰素反应。TRAF3作为ADAP2将RIG-I通路组成蛋白招募到单个大分子复合物中的触发因子。这项研究为抗病毒信号级联不同模块的组装和整合提供了重要的新见解。
