FIGURE 8.

PKCβ is the isoform responsible for Syk negative regulation in human platelets. A, human platelets were stimulated with 200 ng/ml Cvx after preincubation with or without 10 μm Rottlerin, 200 nm PKCδ/θ inhibitor, 3 μm PKCβ inhibitor, 10 μm LY333531, or 5 μm GFX for 5 min and probed for Syk phosphotyrosine 525/526 and total Syk. B, human platelets preincubated with PKC isoform β inhibitor or GFX and were stimulated with 200 ng/ml Cvx for 180 s. Aggregation and secretion were measured by using a lumiaggregometer. C, human platelets were stimulated with 200 ng/ml Cvx after preincubation with or without 0.3 μm, 1 μm, or 3 μm PKCβ inhibitor and probed for Syk phosphotyrosine 525/526 and total Syk. Blots are representative of at least three independent experiments.