Aggregation of Pyk2-deficient platelets. Washed platelets from WT and Pyk2-KO mice were stimulated in an aggregometer with different concentrations of thrombin, AYPGFK, ADP, U46619, or convulxin, as indicated in each panel. For ADP-induced aggregation, 200 μg/mL of fibrinogen was added to the platelet suspension before stimulation with the agonist. Aggregation was monitored as the increase of light transmission up to 5 minutes. Tracings in the figure are representative of at least 3 different experiments.