Purified ANGPTL2 inhibits human platelet activation. (A) The inhibitory effects of 0.5 μg/mL ANGPTL2 (A2) on human platelet aggregation in response to 0.5 μg/mL CRP, 20 μM ADP, and 0.01 U/mL thrombin, respectively. (B) The tyrosine phosphorylation time courses of LAT, SLP76, and PLCγ2 in washed human platelets in response to 0.5 μg/mL CRP with PBS control or 0.5 μg/mL ANGPTL2. IgG was used as a loading control. (C) The phosphorylation time courses of Shp2 Y580 in washed human platelets in response to 0.5 μg/mL CRP with PBS control or 0.5 μg/mL ANGPTL2. GAPDH was used to verify equal loading. (D) Representative phalloidin-stained images of washed human platelets spreading on immobilized Fg for 90 minutes in the presence of PBS, 0.5 μg/mL ANGPTL2, or 1 μg/mL ANGPTL2, respectively. Quantification of the areas (pixel number) of 4 random fields per experiment and ≥3 independent experiments were performed. Statistical analyses were performed using the Student t test (mean ± SD; **P < .01). (E) Phosphorylation of FAK Y397, integrin β3 Y747, Y759, and Shp2 Y580 in human platelets spread on Fg with or without 0.5 μg/mL ANGPTL2. GAPDH was used to verify equal loading.