CRP stimulates shape change and undergoes synergy with ADP in PLCγ2^–/– platelets. Washed platelets from PLCγ2^–/– mice were stimulated with 10 μg/mL CRP (upper trace) or 0.5 μM ADP (middle trace) for 5 minutes. Washed platelets from PLCγ2^–/– mice were stimulated with 0.5 μM ADP for 2 minutes and then stimulated with 10 μg/mL CRP for 5 minutes (lower trace). The data are representative of 3 to 5 experiments.