Type I interferon receptor complex (IFNAR complex)

The **Type I interferon receptor complex** (IFNAR complex) is a heterodimeric cell surface receptor consisting of two subunits, IFNAR1 and IFNAR2, which are expressed on most nucleated cells[2][5][6]. This receptor mediates the biological actions of all type I interferons, including multiple IFN-α subtypes and IFN-β, by binding these cytokines and initiating intracellular signaling. Upon ligand (interferon) binding, the IFNAR1 and IFNAR2 subunits bring together their associated tyrosine kinases—TYK2 and JAK1, respectively—leading to the phosphorylation and activation of STAT1 and STAT2 proteins[2][3][5][6][7]. These STATs then associate with IRF9, forming the ISGF3 complex, which translocates to the nucleus and stimulates transcription of hundreds of interferon-stimulated genes (ISGs) responsible for antiviral defense, immune modulation, cell growth regulation, and apoptotic processes[1][2][6][9]. The receptor system has central importance in innate and adaptive immunity and is implicated in the pathogenesis and treatment of infections (particularly viral), cancers, and autoimmune/inflammatory diseases[1][2][5]. Therapeutic strategies exploit both agonism (recombinant interferons for antiviral/cancer therapy) and antagonism (monoclonal antibodies blocking IFNAR for autoimmune disease modulation). Disruption or excessive activation of this pathway can lead to clinical challenges including heightened autoimmunity and systemic toxicity[5].

Other names

Interferon alpha/beta receptorIFNARType I interferon receptorInterferon-α/β receptorIFNAR1/IFNAR2 complex

Agonism (by IFN-α, IFN-β—induction of JAK-STAT signaling), Antagonism (by monoclonal antibodies blocking IFNAR1 or IFNAR2), Regulation of interferon-stimulated gene (ISG) transcription