TGF-β isoforms-induced phosphorylation/activation of Smad2, Smad3 and IκB-α. HeLa and KLE cells (not shown) were treated with the indicated recombinant TGF-β isoforms (10 ng/mL) or with vehicle for 15 min. Levels of phosphorylated Smad2 (P-Smad2) and phosphorylated Smad3 (P-Smad3) were determined to monitor the activation of Smad pathway by TGF-β isoforms and levels of phosphorylated IκB-α was determined to examine the activation of NF-κB pathway. In all experiments, β-actin was used as a loading control. Graphs represent mean ± SE of three independent experiments. * p < 0.05 compared to control.