Syk phosphorylation in wild-type and TULA-dKO murine platelets. (Ai) Isolated wild-type and TULA-dKO platelets were stimulated with 200 ng/mL convulxin for 0, 30, 60 120, and 240 seconds, the protein precipitated, and pY519/20 Syk and total Erk were probed. (Aii) Mean relative Syk phosphorylation of 3 experiments for covulxin in wild-type (■) and TULA-dKO (□) platelets was plotted against time and a 2-way analysis of variance performed (P < .001, WT vs dKO). (Bi) Same as subpanel Ai, except that platelets were stimulated with 1 μg/mL CRP and total Syk was used as a loading control. (Bii) Same as subpanel Aii, except that CRP was used as agonist (P < .001, WT vs dKO). (Ci) Same as subpanel Bi, except that platelets were stimulated with 50 μg/mL collagen. (Di) Isolated wild-type and TULA-dKO platelets were stimulated for 2 minutes with 50, 100, 200, 400, or 800 ng/mL convulxin, processed for Western blotting, and probed for pY519/20 Syk and total Syk. (Dii) Same as subpanel Aii, except that Syk phosphorylation was plotted as a function of convulxin and curves were fitted using a nonlinear regression (P < .001, WT vs dKO). (Ei) Same as subpanel Di, except that platelets were stimulated with 0.5, 1, 2, 5, or 10 μg/mL CRP. (Eii) Same as subpanel Dii, except that CRP was used as agonist (P < .001, WT vs dKO). (F) Same as subpanel Di, except that platelets were stimulated for 1 minute with 25, 50, or 100 μg/mL collagen. (G) Isolated wild-type and TULA dKO platelets were left untreated or treated with 200 ng/mL convulxin for 4 minutes. Kinase activity of the resulting immunoprecipitates was then measured and plotted as function of time. Shown is a representative plot from 5 independent experiments.