IFITM2 is an interferon-induced transmembrane protein that functions primarily as an antiviral restriction factor and cellular regulator. As an antiviral effector, IFITM2 demonstrates broad-spectrum activity against multiple viruses including hepatitis C virus, yellow fever virus, West Nile virus, chikungunya virus, Venezuelan equine encephalitis virus, and HIV-1 1. The protein enhances type I interferon signaling by binding to and facilitating MDA5 expression, creating a positive feedback loop that amplifies innate immune responses 2. Mechanistically, IFITM2 operates through multiple pathways: it modulates endocytosis via its YXXø endocytic motif and phosphoinositide interactions, which is crucial for maintaining neural stem cells during brain development 3, and acts as a DNA receptor sensing neutrophil extracellular trap DNA to promote regulatory T cell differentiation during sepsis 4. Beyond antiviral functions, IFITM2 exhibits tumor suppressor properties by inducing p53-independent apoptosis through caspase activation and cell cycle arrest in G1 phase 5. The protein demonstrates anti-tumor effects by inhibiting cell proliferation and migration while regulating apoptosis-related genes including BCL2/BAX and mTOR 6. IFITM2 expression correlates with cognitive impairment in both sepsis and Alzheimer's disease, potentially through immune dysregulation mechanisms 7.