IRF3 (interferon regulatory factor 3) is a key transcriptional regulator that controls type I interferon (IFN-α/β) production during innate immune responses to viral infections 1. In unstimulated cells, IRF3 remains inactive in the cytoplasm, but upon viral infection or detection of cytosolic nucleic acids, it undergoes phosphorylation by kinases TBK1 and IKKε 23. This phosphorylation is facilitated by adaptor proteins including STING, MAVS, and TRIF, which recruit IRF3 to kinase complexes through their own phosphorylation-dependent mechanisms 1. Phosphorylated IRF3 dimerizes, translocates to the nucleus, and activates transcription of type I interferons and interferon-stimulated genes by binding to interferon-stimulated response elements (ISRE) in their promoters. Beyond its transcriptional role, phosphorylated IRF3 can promote apoptosis independently of its DNA-binding function 4. IRF3 also plays pathological roles in non-viral contexts, as bile acid-induced IRF3 phosphorylation mediates cell death and inflammation in cholestatic liver injury 5. Additionally, MTAP-deficient tumors show reduced IRF3 expression, conferring resistance to STING agonist immunotherapy 6, highlighting IRF3's clinical relevance in both antiviral immunity and cancer treatment.