SMURF1 expression is also increased by hypoxia or TGF-β signaling, both of which are central drivers of vascular remodeling (Figures S4A and S4B), further implicating SMURF1 as a key mediator of reduced BMP signaling and the subsequent vascular remodeling observed in PAH. This evidence concerns the gene TGFB1 and pulmonary arterial hypertension.