Fig. 1. Actin cytoskeleton configuration regulates Rho activity in HMVE cells. (A) Time course of Rho activity in cells plated on fibronectin-coated dishes in the presence or absence of cytoD (upper panel), and comparison of Rho activity in spread cells versus round cells 1.5 hours after replating (lower panel). Rho activity is presented as the ratio of active RhoA (determined using the rhotekin-RBD bead pull down assay) to total RhoA protein in each cell lysate (upper panel, ^*P<0.05 for Rho activity in spread versus cytoD-treated cells; ⁺P<0.02 for Rho activity at 1 hour after plating versus time zero. Lower panel, ^*P<0.01). (B) Phase contrast and fluorescence images of cells stained for F-actin showing cell morphology and the actin cytoskeleton of HMVE cells in the presence or absence of cytoD (scale bar, 5 µm).