Retinoic acid-inducible gene 1 protein (RIG-1) is a cytoplasmic DExD/H box RNA helicase belonging to the helicase family and containing 2 CARD domains within the N-terminus, a repressor domain (RD), a helicase ATP-binding domain and a helicase C-terminal binding domain. RIG-1 is able to bind the 5'-triphosphate RNA of single or double-stranded viral RNA. After recognizing and binding viral RNA, RIG-1 protein initializes type I IFN production, and within fibroblasts and dendritic cells plays a central role in the regulation of type I IFN production in response to viral presence. There are four known isoforms resulting from alternative splice variants.