Figure 4

TGF-β1 potentiates Cdk5-mediated phosphorylation of TRPV1 in MDPC-23 cells. A, Representative fluorescence of MDPC-23 cells transiently transfected with the TRPV1-GFP plasmid vector after 48 h. After 24 h of transfection, MDPC-23 cells were treated with vehicle (control), TGF-β1 (1 ng/ml), and TGF-β1 (1 ng/ml) plus SB431542 (10 μM), and protein extracts were analyzed by Western blot against phospho-Thr407-TRPV1, TRPV1, and α-tubulin 24 h later. B, Representative Western blot analysis showing phospho-Smad2, Smad2, p35, Cdk5, GFP, TRPV1, and α-tubulin from MDPC-23 cells treated with vehicle (control), TGF-β1 (1 ng/ml), and TGF-β1 (1 ng/ml) plus SB431542 (10 μM) over 24 h. C, Representative Western blot analysis against phospho-Thr407-TRPV1 in MDPC-23 cells treated with vehicle (control), TGF-β1 (1 ng/ml), and TGF-β1 (1 ng/ml) plus SB431542 (10 μM) over 24 h. D, Quantification analysis showed that TGF-β1 treatment significantly increased phospho-Thr407-TRPV1 compared to control, and SB431542 blocked this effect. All data are presented as the mean and SEM (n = 3). *p < 0.05, (t-Test).