Fig. 5. EphrinA1 inhibits the activation of PAK1, an effector of Rac1 signaling. (A) Quiescent VSMCs were seeded on tissue culture dishes coated with laminin and either Fc or ephrinA1/Fc (A1). Cells were lysed in SDS-PAGE loading buffer at the indicated times. PAK1 activity is indicated by the amount of phosphorylated PAK1 (phosphoPAK1) normalized to the total PAK1 in each cell lysate. (B) Densitometric analysis of (A). Results are the mean±s.d. of three independent experiments.