STAT1 is a signal transducer and transcription factor that mediates cellular responses to interferons and cytokines, playing a central role in immune defense and inflammatory regulation. Upon type I interferon (IFN-α/β) binding, STAT1 is phosphorylated by JAK kinases, then dimerizes with STAT2 and IRF-9 to form ISGF3, which translocates to the nucleus and binds IFN-stimulated response elements (ISRE) to activate antiviral gene programs 1. In response to type II interferon (IFN-γ), STAT1 undergoes tyrosine and serine phosphorylation, forming a homodimer (GAF) that binds IFN-gamma activated sequences (GAS) to drive antiviral and inflammatory gene expression 2. Beyond canonical interferon signaling, STAT1 mediates responses to growth factors including KITLG/SCF and FGF receptor signaling, and can be phosphorylated at Thr-749 by IKBKB following LPS stimulation to activate IL6 and IL12B transcription 3. STAT1 dysfunction is associated with immunodeficiency syndromes and gain-of-function variants cause chr2 mucocutaneous candidiasis with predisposition to infections and autoimmunity 45. Recent findings reveal non-canonical functions: STAT1 suppresses HIF1A-driven angiogenesis under ischemic conditions 6, and EGFR-activated STAT1 in fibroblasts drives skin fibrosis independent of interferon signaling 7. Dysregulated STAT1 activity participates in ferroptosis in diabetic nephropathy and vascular calcification via NLRP3 pathway activation 89.