Figure 1.

Opposing effects of paxillin α and p130^Cas on cell migratory activities through tyrosine phosphorylation. (A and B) Haptotactic transmigrating activities toward collagen type I by using modified Boyden chambers. Serum-starved COS7 cells (A) or serum-starved NMuMG cells (B) were allowed to migrate for 3 h on collagen-coated membrane after transfection with either the empty expression vector (vector) or the expression vector containing cDNA for EGFP-paxillin α wt (pax wt), its 4X mutant (pax 4X), EGFP-p130Cas wt (Cas wt), or its ΔSD mutant (Cas ΔSD). COS7 cells were transiently transfected by using FuGENE6 with an efficiency of 40–60%. NMuMG cells were stably transfected by retrovirus infection. Each bar represents the mean +/− SEM of triplicate of three independent experiments. (C) Transcellular invasion activities through mesothelial cell monolayer. LPA-stimulated MM1 cells cultured in the presence of 10% serum, stably expressing each cDNA as indicated, were seeded onto the mesothelial cell monolayer and allowed to migrate for 20 h without serum. Invasive activities of each transfectant were shown as relative activities to the vector control cells. Each bar represents the mean +/− SEM of triplicate of an independent experiments. Levels of exogenous proteins (open arrowheads) compared with endogenous proteins (closed arrowheads), as assessed by immunoblotting by using antipaxillin and anti-p130^Cas, respectively, were also shown below (A–C).