Glycoprotein receptor shedding following PS exposure in CRP-XL/thrombin–stimulated platelets. Washed platelets, which were preincubated with vehicle or ADAM10/17 inhibitor GW280264X (GW; 5 μM), were left unstimulated (Ctrl) or were stimulated with CRP-XL plus thrombin (Thr) for the indicated times and then evaluated for glycoprotein expression by flow cytometry. (A-B) ADAM-dependent decrease in surface expression of GPIbα and GPVI over time. (C-D) Population analysis of platelets after dual staining for GPIbα (FITC mAb) or GPVI (PE mAb) and for PS exposure (AF647-annexin A5). Four platelet populations are defined, as in Figure 2. Note the gradual increase in the PS-exposing platelet populations and the slower increase in populations with shed GPIbα or GPVI. Data are mean ± SD, n = 3-7 (≥3 donors). *P < .05 vs control, ^#P < .05 vs vehicle.