Ablation of Jam-A results in hyperaggregability. (A) Representative aggregation tracings of platelets from Jam-A^wt/wt and Jam-A^gt/gt mice induced by AYPGQV (PAR 4 peptide), ADP, or collagen as indicated. Experiments were performed at least 3 times independently. (B) Surface expression of integrin α_IIbβ₃ on Jam-A^wt/wt and Jam-A^gt/gt platelets as analyzed by flow cytometry. (C) FITC-labeled Fg binding to Jam-A^wt/wt and Jam-A^gt/gt platelets stimulated with 100μM AYPGKF and analyzed by flow cytometry. (D) Representative flow cytometric histogram of JON/A binding to Jam-A^wt/wt and Jam-A^gt/gt platelets stimulated with AYPGKF. Quantitation of mean fluorescence intensity of JON/A binding on stimulation with various concentrations of AYPGKF from 3 independent experiments.