Fig. 2.

Itch regulated TGF-β1-induced Smad3 transcriptional activity by inhibiting Smad7. (A) A549 cells cotransfected with pSBE-luc, pRL-tk, pHA-Smad7 plus pMyc-Itch or pMyc-Itch-mut were not treated (□) or treated (▪) with TGF-β1 (2 ng/ml) for 9 h. Relative luciferase activities were determined by dual luciferase reporter assay using a luminometer. (B) A549 cells were co-transfected with p800-luc, pRL-tk, pMyc-Itch, pMyc-Itch-mut, plus pHA-Smad7 as indicated in the figure, and then treated TGF-β1 (2 ng/ml) for 9 h and lysed to determine luciferase activity. Results are expressed as means ± SDs and are representative of three independent experiments. *p < 0.05, **p < 0.01.