Tyrosine phosphorylation and translocation of LAT in platelets.

Platelet aggregation is accompanied by the tyrosine phosphorylation of several proteins including syk. However, some of these proteins are not identified. Recent studies showed that LAT is a syk substrate and is tyrosine phosphorylated during T cell stimulation. In this study, we demonstrated that LAT is present in platelets and is tyrosine phosphorylated in response to ADP- and thrombin-stimulated aggregation. Moreover, LAT, like syk and beta3, translocates to the cytoskeleton during the late stage of thrombin-stimulated irreversible aggregation and not during ADP-stimulated reversible aggregation.