. "Edited: Garapati, P V, 2010-08-02"^^ . "Reviewed: Kawai, T, Akira, S, 2010-10-30"^^ . "Authored: Garapati, P V, 2010-08-02"^^ . "Human IRF3 is activated through a two-step phosphorylation in the C-terminal domain mediated by TBK1 and/or IKKi, requiring Ser386 and/or Ser385- site 1; and a cluster of serine/threonine residues between Ser396 and Ser405- site 2 [Panne et al 2007]. Phosphorylated residues at site 2 (Ser396\u00E2??Ser405) alleviate autoinhibition to allow interaction with CBP (CREB-binding protein) and facilitate phosphorylation at site 1 (Ser385 or Ser386). Phosphorylation at site 1 is required for IRF3 dimerization.
IRF3 and IRF7 transcription factors possess distinct structural characteristics; IRF7 is phosphorylated on Ser477 and Ser479 residues [Lin R et al 2000].
Since the number of serine residues involved into IRF activation remains unclear this reaction represents a minimum stoichiometry to achieve the phosphorylation of at least 3 Ser residues per each IRF transcription factor. [Lin et al 2000, Ning et al 2008]"^^ . . . . . . . . . . . "Phosphorylation and release of IRF3/IRF7"^^ . . . . . . . .