Ablation of Jam-A results in enhanced c-Src activation. (A) Representative anti-Src pY⁴¹⁸ immunoblots of proteins immunoprecipitated with anti-Src or control IgG from lysates of Jam-A^wt/wt and Jam-A^gt/gt mouse platelets exposed to immobilized Fg or BSA. Blots were reprobed with anti-Src to ensure equal loading. (B) Quantitation of normalized optical density of “A” from 3 independent experiments (P = .05). (C) Representative anti-Src pY⁵²⁹ immunoblots of proteins immunoprecipitated with anti-α_IIb or control IgG from lysates of Jam-A^wt/wt and Jam-A^gt/gt mouse platelets exposed to immobilized Fg or BSA. Blots were reprobed with anti-Src or anti-α_IIb to ensure equal loading. (D) Quantitation of normalized optical density of “C” from 3 independent experiments (*P = .05; **P = .03; ***P = .01). (E) Representative aggregation tracings of Jam-A^wt/wt and Jam-A^gt/gt mouse platelets pretreated with or without PP2 (20 μM) and stimulated with ADP (10 μM). (F) Quantitation of extent of aggregation from E, performed 3 times independently (P = .002).