LAT is a transmembrane molecule that mediates signaling following the engagement of a number of cell surface receptors including TCR during mature T cell activation, pre-TCR during T cell development, Fc RIII on NK cells, and FcepsilonRI on mast cells.LAT is multiply phosphorylated on tyrosines by ZAP-70 and Syk, which leads to downstream effects that include release of intracellular calcium, PKC activation, MAPK activation and cytoskeletal reorganization.Palmitoylation of LAT is required for its localization to lipid rafts and efficient phosphorylation.