Effect of pro-u-PA on actin cytoskeleton (A, C, E, G, I, K, M, O, Q, and S) and vinculin distribution (B, D, F, H, J, L, N, P, R, and T) on RSMC. Cells were incubated in the absence (A and B) or in the presence of 1 nmol/L pro-u-PA for 5 minutes (C and D), for 10 to 15 minutes (E, F, G, H, I, and J), for 30 minutes (K, L, M, N, O, P, Q, and R), or for 120 minutes (S and T). The cells were then fixed and double-stained with fluorescein-conjugated phalloidin to visualize actin filaments and with antibody against vinculin, which was visualized with a rhodamine-conjugated secondary antibody.