RIG-I or Probable ATP-dependent RNA helicase DDX58 or simply DDX58 is a RNA helicase enzyme with two isoforms (106 and 101 kDa). RIG-I belongs to the DEAD/H box family and is involved in several cellular responses including RNA binding and alteration of RNA secondary structure. RIG-1 acts as sensor of viral nucleic acids thus activating a cascade of antiviral responses including the induction of type I interferons and pro-inflammatory cytokines. Generally it remains as a monomer but upon activation by viral dsRNA it homomultimerizes and interacts with mitochondria antiviral signaling protein (MAVS/IPS1) which activating a cascade of reactions to produce specific interferon. RIG-1 is mostly expressed in vascular smooth cells.