The Ca²⁺ response and phosphorylation of PLCγ2 after convulxin stimulation is decreased in Sema4D^(−/−) platelets. (A) Platelets from matched Sema4D^(+/+) and Sema4D^(−/−) mice were loaded with Fura-2 and then stimulated with 0.5nM convulxin (CVX). (B) Summary data (mean ± SEM) from 6 studies with CVX. (C) Summary data from platelets stimulated with the PAR4 agonist peptide, AYPGQV (300μM, mean ± SEM, N = 6). N.S. = not significant. (D) Platelets from matched Sema4D^(+/+) and Sema4D^(−/−) mice were stimulated with 10nM CVX. Phosphorylation of PLCγ2 was measured at the times indicated. A representative immunoblot is shown and the results of 5 experiments are summarized (mean ± SEM). (E) Human platelets preincubated for 15 minutes with either a Sema4D blocking antibody (10 μg/mL) or an immunoglobulin control (10 μg/mL) were stimulated with 1 μg/mL collagen (mean ± SEM, N = 3). N.S. = not significant.