Aggregation of washed platelets from control or SERCA3^−/− mice. Washed platelets from controls (WT, black line) or SERCA3^−/− (gray line) mice were stimulated with collagen (A; 0.8 or 1.2 µg/mL) or with thrombin (B; 40 and 100 mU/mL) and recorded for aggregation for 3 minutes. Aggregation intensities are expressed as percent of light transmitted, 100% corresponding to buffer alone. Note the low aggregation rate of SERCA3^−/− platelets at 0.8 µg/mL of collagen and 40 mU/mL thrombin. These tracings are representative of 5 experiments. (C) Aggregation induced by collagen (0.8 µg/mL) or thrombin (40 mU/mL) of control (WT) and SERCA3^−/− platelets was carried out in the presence of apyrase (5 U/mL, noted “Apy”). (D) Aggregation rescue was conducted on control and SERCA3^−/− washed platelets by addition of 10 µM ADP following stimulation by either collagen (0.8 µg/mL) or thrombin (40 mU/mL). These tracings are representative of 3 experiments.