Deficiency in LAT or PLCγ2 impairs collagen-dependent thrombus formation and platelet procoagulant activity on collagen under coagulant condition. (A) Effect of collagen type I/H (10 μg/mL) on tyrosine phosphorylation of PLCγ2 in platelets from wild types or mice (heterozygously) deficient in LAT or PLCγ2. Western blots of PLCγ2 immunoprecipitates were stained for antiphosphotyrosine (p-Tyr), then reprobed with anti-PLCγ2 mAb (representative for 3 sample sets). Vertical line has been inserted to indicate repositioned gel lanes. (B) Blood from wild-type or deficient mice was flowed over collagen under coagulant condition (Figure 5). Platelet-fibrin thrombi were poststained with OG488-annexin A5. Shown are representative phase-contrast and fluorescent images (180 × 180 μm). (C) Surface area covered by thrombi (□) and annexin A5 fluorescence (■). Mean ± SEM; n = 4-5; *P < .05 vs corresponding wild type.