Fig. 6. p90RSK was involved in TGF-β1-induced Smad3 transcriptional activation and PAI-1 promoter activity. A and B: A549 cells were transfected with pSBE-Luc or p800-Luc, which contain smad binding elements or a fragment of PAI-1 promoter, respectively. Transfected cells were pretreated with FMK (10 µM) or SIS3, a specific inhibitor of Smad3, and then treated with TGF-β1 (2 ng/ml) for 6 hours. C and D: A549 cells were transduced with Ad-LacZ or Ad-DN-p90RSK, transfected with pSBE-Luc or p800-Luc, and then treated with TGF-β1 (2 ng/ml) for 6 hours. Luciferase activities in cell lysates were measured using the Dual luciferase reporter assay kit and a Glomax 20/20 luminometer. Transfection efficiencies were normalized versus renilla luciferase activity derived from pRL-tk construct. Results are presented as the means±SDs of three independent experiments. *, p<0.05; **, p<0.01 versus CON. ^†, p<0.05, ^††, p<0.01 versus TGF-β1 treated.