Figure 2.

Adhesion of neutrophils to fibronectin leads to delayed Rac2 and Pak activation in response to fMLF stimulation. Neutrophils plated on fibronectin (50 μg/ml) or in nonadherent conditions were treated with 1 × 10^–7 M fMLF. After the times indicated, Rac2 activity in the absence or presence of 10 μM DPI was determined, as in Methods. Total Rac2 levels (anti-Rac2 IB) did not change with time under each cond of immunoprecipitated (IP) Pak or directly in cell lysates. IBs in the bottom panel show that Pak (1 and 2) levels did not change with time under each condition. The results shown are representative of four similar experiments obtained with cells derived from different donors.