Rap1 promotes endothelial mechanosensing complex formation, NO release and normal endothelial function.

Decreased nitric oxide (NO) bioavailability underlies a number of cardiovascular pathologies, including hypertension. The shear stress exerted by flowing blood is the main determinant of NO release. Rap1 promotes integrin- and cadherin-mediated signaling. Here, we show that Rap1 is a critical regulator of NO production and endothelial function. Rap1 deficiency in murine endothelium attenuates NO production and diminishes NO-dependent vasodilation, leading to endothelial dysfunction and hypertension, without deleterious effects on vessel integrity. Mechanistically, Rap1 is activated by shear stress, promotes the formation of the endothelial mechanosensing complex-comprised of PECAM-1, VE-cadherin and VEGFR2- and downstream signaling to NO production. Our study establishes a novel paradigm for Rap1 as a regulator of mechanotransduction.