Fig. 2. Rho-dependent ERM protein activation in A431 cells. Serum-starved A431 cells were microinjected with C3/Rh-dextran (A), incubated for 10 minutes, then stimulated with EGF for 5 minutes. Cells were fixed and doubly stained with anti-ERM pAb, TK89 (B) and anti-CPERM mAb (C). C3 completely suppressed both the production of CPERMs and microvillar elongation with concomitant recruitment of ERM proteins. Constitutively active RhoA (V14RhoA) was expressed in serum-starved A431 cells (D,E). Cells were doubly stained with anti-HA mAb for detection of HA-tagged V14RhoA (D) and anti-CPERM mAb (E). CPERMs were dramatically increased in microvilli in cells where Rho activity was increased. Bars, A-C, 10 µm; D,E, 20 µm.