TGF-β1 Induces Activation of Extracellular Signal-Regulated Kinase Through TβRII and Smad7

Objective To investigate the mechanism of TGF-β on the phosphorylation of extracellular signal-regulated kinase ERK or p44/42 in human bronchial epithelial BEP2D cells. Methods siRNAs were designed to specifically target TβRⅡ and Smad7 of BEP2D cells. siRNA transfection and Western blot were performed to examine the phosphorylation of ERK. Results Smad7 gene silencing leads to the phosphorylation level of ERK decreased. When expression of TβRⅡ and Smad7 was knock-down at the same time TGF-β1-induced phosphorylation level of ERK is decreased further and lower than the control cells. Conclusions TGF-β1 activate ERK/MAPK signaling in a TβRⅡ and Smad7 dependent manner.