Shh is required to sustain ERK1/2 phosphorylation induced by PDGF-BB. (A) Quiescent SMCs were stimulated for 15 minutes with Shh (1 µg/mL). Proteins were extracted and processed for detection of ERK1/2 and phosphorylated ERK1/2 (p-ERK1/2) by western blot. (B) Kinetics of ERK1/2 phosphorylation in the presence or absence (Ctrl) of the Hh blocking antibody 5E1 (Anti-Hh ab; 1.5 µg/mL). Immunoblots shown are representative of 3 independent experiments. (C) Quantification of band intensity. (D) Kinetics of ERK1/2 phosphorylation in the presence or absence (Ctrl) of the Smo inhibitor cyclopamine (1 µmol/L). Immunoblots shown are representative of 3 independent experiments. (E) Quantifications of band intensity. *P < .05.