Fig. 5. p90RSK was not involved in TGF-β1-induced nuclear translocation of Smad3. A: Human lung fibroblasts were incubated with 10 µM FMK for 1 hour and then incubated with TGF-β1 (2 ng/ml) for 30 minutes. Cells were stained with anti-Smad3 antibody and nuclei were stained with DAPI. Cells were visualized at x200 under an immunofluorescence microscope (Olympus, Tokyo, Japan). B: Fibroblasts were pretreated with 10 µM FMK for 1 hour and then incubated with TGF-β1 (2 ng/ml) for 30 or 60 minutes. Nuclear and cytosol compartments were obtained by cellular fractionation as described in Materials and Methods. Cellular localizations of Smad3 were determined by immunoblotting with anti-Smad3 antibody and specific antibodies of lamin B1 and tubulin. Bar graphs represent densitometric results of Western blot bands. Results are presented as the means±SDs of three independent experiments. *: p<0.05; N.S.: not significant (n=3).