Required for innate immune defense against viruses. Acts downstream of DDX58 and IFIH1/MDA5, which detect intracellular dsRNA produced during viral replication, to coordinate pathways leading to the activation of NF-kappa-B, IRF3 and IRF7, and to the subsequent induction of antiviral cytokines such as IFN-beta and RANTES (CCL5). May activate the same pathways following detection of extracellular dsRNA by TLR3. May protect cells from apoptosis (By similarity).