CRP-stimulated tyrosine phosphorylation in wild-type andfyn^−/−lyn^−/−platelets.

Platelets in this experiment were treated with 1 mmol/L EGTA and 10 μmol/L indomethacin. (A) Antiphosphotyrosine immunoblots show tyrosine phosphorylation at 0, 30, and 180 seconds in CRP (1.0 μg/mL)-stimulated wild-type andfyn^−/−lyn^−/−platelets. The 12- to 14-kd band corresponds to the FcRγ chain. Phosphorylation of Syk (B) and PLCγ2 (C), measured after immunoprecipitation from platelets stimulated as in panel A. Results are representative of 3 experiments. Wild-type and knockout samples were obtained from experiments run in parallel. Results shown in each panel of A are from samples resolved on the same gel and are from the same exposure on the same film. This also applies to B-D.