Acts as a regulator of DDX58/RIG-I and IFIH1/MDA5 mediated antiviral signaling. Cannot initiate antiviral signaling as it lacks the CARD domain required for activating MAVS/IPS1-dependent signaling events. Can have both negative and positive regulatory functions related to DDX58/RIG-I and IFIH1/MDA5 signaling and this role in regulating signaling may be complex and could probably depend on characteristics of the infecting virus or target cells, or both. Its inhibitory action on DDX58/RIG-I signaling may involve the following mechanisms: competition with DDX58/RIG-I for binding to the viral RNA, binding to DDX58/RIG-I and inhibiting its dimerization and interaction with MAVS/IPS1, competing with IKBKE in its binding to MAVS/IPS1 thereby inhibiting activation of interferon regulatory factor 3 (IRF3). Its positive regulatory role may involve unwinding or stripping nucleoproteins of viral RNA thereby facilitating their recognition by DDX58/RIG-I and IFIH1/MDA5. Involved in the innate immune response to various RNA viruses and some DNA viruses such as poxviruses, and also to the bacterial pathogen Listeria monocytogenes. Can bind both ssRNA and dsRNA, with a higher affinity for dsRNA. Shows a preference to 5'-triphosphorylated RNA, although it can recognize RNA lacking a 5'-triphosphate. ATP + H2O = ADP + H(+) + phosphate Monomer in the absence of dsRNA. Homodimer in the presence of dsRNA. Interacts with DDX58/RIG-I (via CARD domain), MAVS/IPS1 and DDX60. Found in a complex with DDX58/RIG-I and IFIH1/MDA5. Interacts with ANKRD17. Directly interacts with ATG5 and ATG12, either as ATG5 and ATG12 monomers or as ATG12-ATG5 conjugates (By similarity). Highly expressed in mammary tissues. Expressed in liver and testis. Expressed at lower level in spleen, embryo, mammary gland and breast tumors. By interferon (IFN), virus infection, or intracellular dsRNA. The RLR CTR domain is capable of inhibiting dimerization and signaling of DDX58/RIG-I and also facilitates binding of dsRNA. Embryonic lethality at a high frequency. Adult female that survive show an enlarged uterus filled with fluid resulting from vaginal atresia. Belongs to the helicase family. RLR subfamily.