aPKCζ is required for EGF-dependent RhoA activation. (A) Lysates aPKCζ−/− and control cells that were stimulated with EGF for 4 min, were subjected to affinity precipitation with GST-Rhotekin beads. Proteins bound to GST-Rhotekin beads (RhoA-GTP) and cell lysate (total RhoA) were separated on SDS-PAGE and immunoblotted for RhoA. (B) Relative amounts of RhoA-GTP to RhoA are shown. Values represent the mean ± SEM for 4 independent experiments, *** p < 0.001, values are aPKCζ−/− cells compared with control cells. (C) aPKCζ−/− and control cells were placed on cover slips, stimulated with EGF for 4 min, stained with anti-RhoA antibodies, and secondary antibody conjugated to Cy2. Bars are 10 μm.