GPVI agonists induce fibrinogen binding to integrin α_IIbβ₃ but not secretion in FcRγ-chain^–/– platelets. (A,D) Washed platelets from wild-type (i), PLCγ2^–/– (ii), and FcRγ-chain^–/– (iii) mice were stimulated with indicated concentrations of CRP (A) or 40 μg/mL convulxin (D) for 5 minutes in the presence or absence of fibrinogen (200 μg/mL). (B) Washed platelets from wild-type (WT) and PLCγ2^–/– mice were stimulated without (shaded area) or with (unshaded area) 20 μg/mL CRP and incubated with FITC-labeled anti–P-selectin antibody for 10 minutes. Fluorescence was analyzed by flow cytometry. (C) Washed platelets from wild-type (WT) and PLCγ2^–/– mice were stimulated without (shaded area) or with (unshaded area) 20 μg/mL CRP in the presence of fibrinogen (200 μg/mL) and incubated with FITC-labeled anti-fibrinogen antibody for 20 minutes. Fluorescence was analyzed by flow cytometry.