page_title: RIG-I
section_title: Structure
hierarchical_section_title: RIG-I / Structure
caption_attribution_description: English: This shows RIG-I in the inactive and active state.
context_page_description: RIG-I is a cytosolic pattern recognition receptor responsible for the type-1 interferon response. RIG-I is an essential molecule in the innate immune system for recognizing cells that have been infected with a virus. These viruses can include West Nile virus, Japanese Encephalitis virus, influenza A, Sendai virus, flavivirus, and coronaviruses. RIG-I is structurally considered a helical ATP-dependent DExD/H box RNA helicase, that recognizes short viral double-stranded RNA in the cytosol during a viral infection or other irregular RNAs. Once activated by the dsRNA, the N-terminus caspase activation and recruitment domains migrate and bind with CARDs attached to mitochondrial antiviral signaling protein to activate the signaling pathway for IFN1. IFN1s have three main functions: to limit the virus from spreading to nearby cells, promote an innate immune response, including inflammatory responses, and help activate the adaptive immune system. Other studies have shown that in different microenvironments, such as in cancerous cells, RIG-I has more functions other than viral recognition. RIG-I orthologs are found in mammals, geese, ducks, some fish, and some reptiles.
context_section_description: RIG-I is encoded by the DDX58 gene in humans. RIG-I is a helical ATP-dependent DExD/H box RNA helicase with a repressor domain (RD) on the C-terminus that binds to the target RNA. Included on the N-terminus are two caspase activation and recruitment domains (CARDs) that are important for interactions with mitochondrial antiviral signaling protein (MAVS). RIG-I is a member of the RIG-I like receptors (RLRs) that also includes Melanoma Differentiation-Associated protein 5 (MDA5) and Laboratory of genetics physiology 2 (LGP2). RIG-I and MDA5 are both involved in activating MAVS and triggering an antiviral response.
caption: This image shows the basic structure of RIG-I while it is inactive and active. Shown are the N-terminus CARDs, the DExD/H helicase domain, and the C-terminus repressor domain (RD). Included on the active structure is the most common RIG-I PAMP, dsRNA with a 5' triphosphate (5'ppp).
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