Activity of SRC tyrosine kinases is required for PMNL adhesion to CHO-P cells and for CHO-P cell–induced P-110 tyrosine phosphorylation.

(A) HE-loaded PMNLs were preincubated for 1 minute at 37°C with different concentrations of PP1 (■), PD98059 (▪), or piceatannol (○), before addition to BCECF-loaded CHO-P cells. Mixed-cell suspensions were coincubated in standard conditions, the interaction was stopped at 2 minutes, and samples were processed for FACS analysis. The percentage of CHO-P cells binding PMNLs from representative of 2 different experiments was reported. (B) PMNLs were preincubated for 1 minute at 37°C with different concentrations of PP1 or with 50 μM piceatannol or PD98059 before coincubation with CHO-P cells in standard conditions. The interaction was stopped at 2 minutes, and samples were processed for analysis of protein tyrosine phosphorylation. The figure shows the tyrosine-phosphorylated 110-kd protein from a representative of 2 different experiments.