The tyrosine residues within these motifs become phosphorylated by  Src family kinases following interaction of the receptor molecules with their ligands. Phosphorylated ITAMs serve as docking sites for other proteins containing a SH2 domain, usually two domains in tandem, inducing a signaling cascade mediated by Syk family kinases (which are the primary proteins that bind to phosphorylated ITAMs), namely either Syk or ZAP-70, resulting mostly in the activation of given cell.
The tyrosine residues within these domains become phosphorylated by  Src family kinases upon ligand binding. Phosphorylated ITAMs serve as sites for recruitment of SH2-containing proteins, usually two in tandem, initiating a signaling cascade mediated by Syk family kinases (Syk or ZAP-70), resulting primarily in cell activation.