Platelet function in PKCε-null mice.

<p>(A) Aggregation and ATP secretion. Washed platelets from PKCε-deficient (PKCε^−/−) mice or wild-type (WT) littermate controls were stimulated with the indicated concentrations of CRP, collagen or PAR4 peptide. Aggregation and dense granule secretion were investigated using light-scattering aggregometry and luciferin-luciferase luminescence, respectively. Traces are representative of between 3–7 mice. (B) Spreading. PKCε^−/−and wild-type (WT) washed platelets in the presence of apyrase (2.5 U/ml) and indomethacin (10 µM) were exposed to surfaces of 100 µg/ml fibrinogen (FG), 1 U/ml thrombin (Thr), or 100 µg/ml collagen (COLL) for 45 min before fixing and mounting. Representative images from each condition are shown. Histograms depict levels of platelet adhesion to each surface and platelet mean surface area (spreading). The results are from one experiment that is representative of three. (C) Expression levels of surface glycoproteins. PKCε^−/− and WT washed platelets were incubated with FITC-labelled antisera against (upper panels) GPVI and integrin α_IIbβ₃ and (lower panels) integrin α₂β₁ and expression levels analysed by flow cytometry. The shaded area represents the signal from non-specific IgG control.