EGFP-CTD localization after PMA or cytochalasin B treatment. (A) Untreated (UNTR) transiently EGFP-CTD–expressing HeLa cells labeled with TRITC-phalloidin (for F-actin) and anti-ERM antibody (detected with Cy5) showed discrete colocalization at the PM (left), whereas enhanced colocalization was observed at the leading edges of the cell after PMA stimulation, resulting in a white color (right). (B) Cytochalasin B treatment of transiently EGFP-CTD–expressing HeLa cells followed by labeling with TRITC-phalloidin for F-actin and anti-ERM antibody (Cy5). The merged CLSM image confirms the presence of distinct structures containing all three proteins at the PM (arrows).