Type I interferon pathway components (IFN-I pathway)

The Type I interferon (IFN-I) pathway is a critical component of the innate immune system, primarily responsible for mediating antiviral, antiproliferative, and immunomodulatory effects. The pathway is initiated when Type I interferons, such as IFN-alpha and IFN-beta, bind to the heterodimeric Type I interferon receptor (IFNAR), consisting of IFNAR1 and IFNAR2 subunits. This binding triggers the activation of receptor-associated Janus kinases, specifically JAK1 and TYK2, which subsequently phosphorylate STAT1 and STAT2. These phosphorylated proteins dimerize and associate with IRF9 to form the ISGF3 complex, which translocates to the nucleus to drive the expression of hundreds of interferon-stimulated genes (ISGs). While essential for host defense against pathogens, chronic or dysregulated activation of this pathway is a hallmark of various autoimmune diseases, most notably systemic lupus erythematosus (SLE) and certain rare genetic interferonopathies. Consequently, therapeutic strategies focus on either supplementing the pathway to treat viral infections and cancers or inhibiting specific components, such as IFNAR or TYK2, to manage chronic inflammatory and autoimmune conditions.

Other names

Type I interferon signaling pathwayIFN-alpha/beta signaling pathwayAntiviral response pathwayIFN-I signaling cascade

Drugs targeting this pathway act as Type I interferon receptor (IFNAR) antagonists, Janus kinase (JAK) inhibitors, Tyrosine kinase 2 (TYK2) inhibitors, or exogenous Type I interferon agonists to modulate the downstream transcription of interferon-stimulated genes (ISGs).