The RIG-I like receptors (RLRs) are cytosolic pattern recognition receptors of viral RNA that mediate the innate anti-viral immune responses. Structural domains comprising this superfamily share the structure of the C-terminal domain of RIG-I (Retinoic acid Inducible Gene - I), a RLR that recognizes pathogen-associated molecular pattern (PAMP) motifs to differentiate between viral and cellular RNAs. Its C-terminal regulatory domain (CTR) binds viral RNA in a 5'-triphosphate-dependent manner and activates the RIG-I ATPase by RNA-dependent dimerization. To facilitate the detection of a broad range of non-self RNA targets, each RLR contains a similar but divergent CTR domain that mediates RLR-specific interactions between bound nucleic acids or neighbouring patterns PMID:20961956 PMID:18243112.