RLR Family of Proteins Melanoma differentiation-associated protein 5 (MDA5), also known as interferon-induced helicase-1 (IFH1), is one of the three members of the RIG-like receptors (RLRs) family of proteins. The RLR family of proteins share similar protein domains essential for their functions – namely the N-terminal caspase activation and recruit domains (CARDs), DExD/H box RNA