PI3K-C2α^WT/D1268A mice exhibit defective platelet activation and prothrombotic capacity. (A) Tail bleeding time of WT (n = 17) and PI3K-C2α^WT/D1268A (n = 18) mice was measured as described in Methods. (B) Thrombotic response of mice to ferric chloride injury of the carotid artery. Time to occlude (blood flow arrest) was measured in the carotid artery after exposure to 7.5% FeCl₃ for 3 minutes (mean ± SEM; n = 14 mice; P < .005 according to 2-tailed Student t test). (C) DiOC₆-labeled platelets in whole blood were perfused through a collagen-coated microcapillary at a shear rate of 20 dynes/cm² during 3 minutes. Thrombus formation was visualized in real time. Scale bar: 20 μm. Area covered by platelet thrombi and thrombus volume were measured using Image J software (mean ± SEM; n = 3; *P < .05, **P < .01 vs WT according to 2-tailed Student t test and 2-way ANOVA).