 They are found in the cytoplasmic tails of non-catalytic tyrosine-phosphorylated receptors  such as the CD3 and ζ-chains of the T cell receptor complex, the CD79-alpha and -beta chains of the B cell receptor complex, and certain Fc receptors.The tyrosine residues within these motifs become phosphorylated by Src family kinases (SFK) following interaction of the receptor molecules with their ligands.Phosphorylated ITAMs serve as docking sites for other proteins containing a SH2 domain inducing a signaling cascade resulting in the activation of the immune cell.