Characterization of EphB2^LacZ platelets. The presence of EphB2 (A), β-galactosidase (B), and ephrinB1 (C) was confirmed in control (a) and EphB2^LacZ (b) mouse platelets by immunoblot analysis. Similarly, the expression level of P-selectin was measured in control (a) and EphB2^LacZ (b) mouse platelets by immunoblot analysis (D). The expression levels of αIIbβ3 (E), α₂β₁ (F), GPVI (G), and GPIbα (H) were analyzed on control and EphB2^LacZ platelets by flow cytometry. Data represent mean (of median fluorescence intensity) ± SD (n = 4, control and EphB2^LacZ mice). (I) ephrinB1 was immunoprecipitated from control and EphB2^LacZ platelets following stimulation with CRP-XL (0.5 µg/mL) and analyzed for its phosphorylation using anti-phosphotyrosine antibody by immunoblotting. The blots are representative of 3 separate experiments. CRP-XL, cross-linked collagen-related peptide; GP, glycoprotein; SD, standard deviation.