RIG-I-Like Receptors Retinoic acid-inducible gene 1 (RIG-I) is a cytoplasmic RNA helicase member of the RIG-I-like receptor (RLR) family of proteins. RIG-I is highly conserved within vertebrates. Structurally, RIG-I is comprised of three main functional domains – Caspase Activation and Recruitment Domain (CARD) for signal transduction, DExD/ H-box RNA helicase domain, and C-terminal domain for