Phosphorylation of Akt (Ser473) requires Lyn, Syk, and SLP-76, but not Src and PLCγ2. (A) Akt was not phosphorylated in Lyn^–/– platelets stimulated by bt/VWF. (B) Akt was phosphorylated in Src^–/– platelets. (C) Akt was phosphorylated in PLCγ2^–/– platelets in response to bt/VWF. (D) Akt was not phosphorylated in Syk^–/– platelets stimulated by bt/VWF. (E) Akt was not phosphorylated in SLP-76^–/– platelets in response to bt/VWF. The results shown here are representative of 4 experiments.