Our study further demonstrates that nedd4 inhibits the TGF-β/Smad pathway by promoting the ubiquitination of p-Smad3 in a model of TGF-β1-induced myofibroblast transformation, suggesting that Nedd4 could also serve as a potential therapeutic target for pulmonary fibrosis. The gene discussed is NEDD4; the disease is pulmonary fibrosis.