Positively regulates DDX58/RIG-I- and IFIH1/MDA5-dependent type I interferon and interferon inducible gene expression in response to viral infection. Binds ssRNA, dsRNA and dsDNA and can promote the binding of DDX58/RIG-I to dsRNA. Exhibits antiviral activity against hepatitis C virus and vesicular stomatitis virus (VSV). ATP + H2O = ADP + H(+) + phosphate Interacts with EXOSC1, EXOSC4, DDX58/RIG-I, IFIH1/MDA5 and DHX58/LGP2. Brain, lymph node, prostate, stomach, thyroid, tongue, trachea, uterus, skeletal muscle, spleen, kidney, liver and small intestine. By interferon (IFN). Up-regulated during vesicular stomatitis virus (VSV), or poliovirus (PV) infection. Belongs to the helicase family.