Platelet adhesion to dA1VWF causes αIIbβ3 activation. Cells were plated over coverslips coated with dA1VWF (A-D) or BSA (E) for 40 minutes in the presence of PAC-1. Platelets were then fixed and stained with an FITC-conjugated antibody against PAC-1 and imaged by confocal microscopy. (A) Platelets adherent to dA1VWF in the presence of inhibitors of signaling through ADP and thromboxane A2 receptors. (B) Same as panel A but no such inhibitors. (C) Platelet adhesion to dA1VWF in the presence of 200 nM PMA to activate PKC. (D) Platelet adhesion to dA1VWF in the presence of αIIbβ3 antagonist, Ro 44-9883 (Ro; 10 μM). (F) Heterogeneity of αIIbβ3 activation in the platelet population under conditions in which signaling through ADP and thromboxane A2 receptors was inhibited. Depicted is the cumulative frequency distribution of fluorescence values within the platelet population.
