In pathological conditions, dysfunctional ECs also show altered intracellular trafficking and signaling of cell surface receptors such as the transforming growth factor beta receptor 1 (TGFβR1) implicated in the pathogenesis of PAH (Garcia-Rivas et al., 2017; Graf et al., 2018). Here, TGFBR1 is linked to pulmonary arterial hypertension.