AAT induces activation of Rac1/Cdc42 (A) and ERK1/2 (B). Neutrophils were treated with AAT (0.5 mg/mL) for the indicated periods at 37°C, 5% CO2. Cell lysates from 3 × 106 neutrophils were separated on 7.5% SDS-PAGE followed by immunoblotting, as described in Materials and Methods. Immunoblotting was performed using antibodies against Rac1 and Cdc42 and against the phosphorylated and unphosphorylated forms of ERK. Presumably because of the stress of the cell culture, the phosphorylation of ERK was also detected in unstimulated control cells to a lesser degree than in AAT-treated neutrophils incubated for 60 min. The results shown are representative of three or five independent experiments.