Recent work from our group and others has implicated the Hippo-Yap/Taz signaling pathway as a regulator of alveolar epithelial development and repair (3–5), and dysregulation of this pathway is a prominent feature of the distal lung epithelium in idiopathic pulmonary fibrosis (6). The gene discussed is WWTR1; the disease is idiopathic pulmonary fibrosis.