Dose-response and time course studies of collagen and CRP stimulation of tyrosine phosphorylation. Platelets (4 × 10⁸/mL) were stimulated with collagen or CRP as indicated. Whole cell lysates were resolved on 10% SDS-PAGE and immunoblotted using antiphosphotyrosine MoAb 4G10. Time-matched ECL exposures of platelets stimulated by collagen (i and ii) and CRP (iii and iv) are shown. The time course of tyrosine phosphorylation stimulated by collagen (30 μg/mL) and CRP (3 μg/mL) are shown in (i) and (iii), respectively. The concentration response relationship (90 seconds of incubation) for tyrosine phosphorylation by collagen and CRP are shown in (ii) and (iv), respectively. The time course and dose-response relationships were determined on separate donors. Similar results were observed on 10 donors.