Vasodilator-stimulated phosphoprotein (VASP) belongs to the Ena/VASP family of adaptor proteins linking the cytoskeletal system to the signal transduction pathways. VASP functions in cytoskeletal organization, fibroblast migration, platelet activation and axon guidance. Three phosphorylation sites, Ser157, Ser239 and Thr278, have been identified. Ser157 is the major PKA phosphorylation site. Evidence sμggests that VASP phosphorylation reduces its association with actin and has a negative effect on actin polymerization.