Recent studies found that expression of NEDD4-2 is reduced in lung tissue from patients with idiopathic pulmonary fibrosis (IPF) and that the conditional deletion of Nedd4-2 in lung epithelial cells causes IPF-like disease in adult mice via multiple defects, including dysregulation of the epithelial Na+ channel (ENaC), TGFβ signaling and the biosynthesis of surfactant protein-C proprotein (proSP-C). This evidence concerns the gene NEDD4L and idiopathic pulmonary fibrosis.