Fig. 1. Smad7-dependent activation of the actin filament system. PC-3U/pMEP4-S7 cells were serum-starved in 1% FBS for 12 hours and treated with 1 µM CdCl2 for 12 hours or 24 hours, or with 1 µM CdCl2 for 12 hours together with TGF-ß for 30 minutes and 12 hours or 24 hours. The expression of Flag-tagged Smad7 was visualized by a Flag-specific mouse antibody (M5) followed by a FITC-labeled anti-mouse antibody. Filamentous actin was visualized by TRITC-labeled phalloidin. Arrowheads indicate cells with lamellipodia. Bars, 20 µm.