Fig. 6.

Clot retraction is delayed in the absence of ESAM. (A, B) Wild-type and ESAM^−/− platelets were spread on immobilized fibrinogen in the presence of the PAR-4 agonist AYPGKF (200 μM). The time stamp indicates time after initial contact for the platelet shown. The area (mean ± SEM) of platelets over time in two independent experiments is reported in (B). Black circles represent wild-type and gray circles represent ESAM^−/− platelets. (C, D) Clot retraction was induced by adding 10 U mL⁻¹ thrombin to either wild-type or ESAM^−/− PRP at 37 °C. Image is representative of difference 30 min after the addition of thrombin. Clot retraction was quantified by determining the two-dimensional area occupied by the clot as described in Methods. Values are mean ± SEM for six mice in each group.