PKC activation elicited by bt/VWF is dependent on Lyn, Syk, PI3K, and PLCγ2. This assay demonstrates activation of PKC as exemplified by phosphorylation of PKC-specific peptide substrate. Phosphorylated peptide substrate moves toward the positive electrode in the assay. (A) In contrast to wild-type platelets, PKC was not activated in Lyn^–/– platelets stimulated with bt/VWF. (B) PP2 and wortmannin each blocked the activation of PKC. (C) Syk and (D) PLCγ2 also are required for PKC activation. The results shown here are representative of 3 experiments.