(A–F) Silencing MiD49 or MiD51 inhibits phosphorylation of Drp1Ser616 and reduces activation of ERK1/2 and CDK4 while reducing expression of PDGF receptors. Representative images of the immunoblots and the densitometries of the expressions of (A) p-Drp1ser616, (B) p-ERK1/2, (C) PDGF receptors α and β, (D) p-CDK4Thr172, (E) p21Waf1 and (F) p27Kip1. PAH PASMCs were transfected with siMiD49 or siMiD51. Cells were harvested for immunoblot analyses after 48h of transfection. β-actin was used as the loading control (*P < 0.05, **P < 0.01, ***P < 0.001; n=3–4/group).