RIG-I and MDA5 have two N-terminal caspase activation and recruitment domains (CARDs) that are responsible for the interaction between activated RIG-I or MDA5 and the adaptor protein mitochondrial antiviral signaling (MAVS), which mediates the activation of NF-κB, IRF3, IRF7, and ATF2 in response to viral infection [143]. This evidence concerns the gene IFIH1 and viral infectious disease.