sentences:  Phosphotyrosine residues on IFNAR1 and IFNAR2 recruit STAT proteins (classically STAT1, STAT2, or STAT3, although STAT4, STAT5, and STAT6 may play a role in certain cell types) via their SH2 domains.Once recruited, STAT proteins are phosphorylated by which induces their homo- or heterodimerization.These dimers translocate to the nucleus, binding interferon-stimulated response elements (ISRE) and gamma activating sequences (GAS), promoting gene transcription.