Role of p72^syk in PI3K-mediated uncoupling of β₃-integrin–mediated transmatrix migration.

(A) Isolated human PMNs were pre-exposed to vehicle (−Wort) or wortmannin (+Wort, 100 nM) and adhered to matrix substrates (top 2 blots) or left in suspension. PMNs were exposed to fMLP (10 nM) for indicated times (0-30 minutes). Cells were lysed and β₃-integrin was immunoprecipitated and resolved by SDS-PAGE. Association with p72^syk was assessed by immunoblot . Data are representative from 3 separate experiments. (B) PMNs were pre-exposed to vehicle (C), wortmannin (WT, 100 nM) or indicated concentrations of the p72^syk inhibitor piceatannol for 20 minutes at room temperature followed by examination of fMLP-stimulated (10⁻⁸ M) transmigration across matrix-coated substrates. Transmigrated PMNs were quantified by determination of MPO content following termination of the assay. Data are derived from 8 to 10 monolayers in each condition from 3 separate experiments with results expressed as mean ± SEM number transmigrating PMNs .