1. Department of Pharmacology and Molecular Cardiobiology Program, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA
2. Cardiovascular Research, St. Elizabeth's Medical Center, Boston, Massachusetts 02135, USA
3. Department of Pharmacology, Columbia University, New York, New York 10032, USA

Correspondence to: William C. Sessa¹ Correspondence and requests for materials should be addressed to W.C.S. (e-mail: Email: william.sessa@yale.edu).

Abstract

Endothelial nitric oxide synthase (eNOS) is the nitric oxide synthase isoform responsible for maintaining systemic blood pressure, vascular remodelling and angiogenesis^{1, 2, 3, 4}. eNOS is phosphorylated in response to various forms of cellular stimulation^{5, 6, 7} but the role of phosphorylation in the regulation of nitric oxide (NO) production and the kinase(s) responsible are not known. Here we show that the serine/threonine protein kinase Akt (protein kinase B) can directly phosphorylate eNOS on serine 1179 and activate the enzyme, leading to NO production, whereas mutant eNOS (S1179A) is resistant to phosphorylation and activation by Akt. Moreover, using adenovirus-mediated gene transfer, activated Akt increases basal NO release from endothelial cells, and activation-deficient Akt attenuates NO production stimulated by vascular endothelial growth factor. Thus, eNOS is a newly described Akt substrate linking signal transduction by Akt to the release of the gaseous second messenger NO.