CLEC-2–mediated signaling is enhanced in Syk(Y317F) platelets. (A) Representative western blots showing the phosphorylated and total proteins in Syk(Y317F) and WT littermate control platelets stimulated with the indicated concentrations of CLEC-2 antibody. (B-E) Quantification of the indicated phosphorylated residues, depicted as the ratio of pY to total protein.