RIG-I

1. 본문

RIG-I (Retinoic acid-inducible gene I) is a crucial component of the innate immune system, acting as a cytosolic pattern recognition receptor (PRR). It plays a key role in detecting viral infections and triggering an antiviral response. Here's a breakdown of RIG-I:
Function:

• Viral RNA Sensor: RIG-I primarily senses viral RNA in the cytoplasm of cells. It specifically recognizes:
• Short double-stranded RNA (dsRNA).
• Single-stranded RNA (ssRNA) with a 5'-triphosphate end, a characteristic often found in viral RNA but not in host RNA.
• Initiates Antiviral Response: Upon binding to viral RNA, RIG-I undergoes conformational changes and activates a signaling cascade.
• Type I Interferon Production: This cascade leads to the production of type I interferons (IFNs), primarily IFN-α and IFN-β. Type I IFNs are critical for:
• Limiting viral spread to neighboring cells.
• Promoting an innate immune response, including inflammation.
• Activating the adaptive immune system.
• Pro-inflammatory Cytokine Production: Besides IFNs, RIG-I activation also stimulates the production of pro-inflammatory cytokines, further enhancing the immune response.
• Detects various viruses including, West Nile virus, Japanese Encephalitis virus, influenza A, Sendai virus, flavivirus, and coronaviruses

• Encoded by: The *DDX58* gene in humans.
• Domains:
• CARDs (Caspase Activation and Recruitment Domains): Two N-terminal CARDs are essential for interacting with the adaptor protein MAVS (mitochondrial antiviral signaling protein), also known as VISA, Cardif, or IPS-1.
• Helicase Domain: A central ATP-dependent DExD/H box RNA helicase domain is responsible for binding to RNA and unwinding it.
• CTD (C-terminal Domain) and RD (Repressor Domain): The C-terminal domain (CTD) binds to viral RNA, while the repressor domain (RD) regulates RIG-I activity.

• RIG-I expression can be induced by various factors, including retinoic acid, lipopolysaccharide (LPS), IFN, and viral infection itself.
• It has been found that RIG-I activation can also cause damage to organs and tissues.
• Self-RNAs do not activate RIG-I signaling because their 5'ppp is capped by 2'O-methylation.

• Granulocyte production and differentiation.
• Bacterial phagocytosis.
• Regulation of cell migration.
• Responding to cytosolic DNA.
• Inflammation related to non-viral triggers like LPS and certain cytokines.
• Plays a role in macrophage activation.