title: c-Jun N-terminal kinase 2 phosphorylates endothelial nitric oxide synthase at serine 116 and regulates nitric oxide production.
abstract: The c-Jun N-terminal kinases (JNKs) belonging to the mitogen-activated protein kinase (MAPK) superfamily play important roles in foam-cell formation, hypercholesterolemia-mediated endothelial dysfunction, and the development of obesity. Although decreased nitric oxide (NO) production via decreased phosphorylation of endothelial NO synthase at serine 1179 (eNOS-Ser(1179)) was reported to be partly involved in JNK2-derived endothelial dysfunction, JNK2 seems likely to be indirectly involved in this signaling pathway. Here, using bovine aortic endothelial cells, we examined whether JNK2 directly phosphorylated eNOS-Ser(116), a putative substrate site for the MAPK superfamily, and this phosphorylation resulted in decreased NO release. JNK inhibitor SP60012 increased NO release in a time- and dose-dependent manner, which was accompanied by increased eNOS-Ser(116) phosphorylation. Purified JNK2 directly phosphorylated eNOS-Ser(116)in vitro. Ectopic expression of dominant negative JNK2 repressed eNOS-Ser(116) phosphorylation and increased NO production. Coimmunoprecipitation and confocal microscopy studies revealed a colocalization of eNOS and JNK2. However, all these observed effects were not manifested when JNK1 probes were used. Overall, this study indicates that JNK2 is a physiological kinase responsible for eNOS-Ser(116) phosphorylation and regulates NO production.
authors.affiliation: Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul, South Korea.
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Meanha
authors.initials: M
authors.lastname: Park
authors.forename: Catherine Jeonghae
authors.initials: CJ
authors.lastname: Byun
authors.forename: Inho
authors.initials: I
authors.lastname: Jo
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D048056:Mitogen-Activated Protein Kinase 9 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D012694:Serine / Q000235:genetics / Q000378:metabolism*
chemical_list: D000873:Anthracenes; C432165:pyrazolanthrone; D009569:Nitric Oxide; D012694:Serine; D052250:Nitric Oxide Synthase Type III; D048056:Mitogen-Activated Protein Kinase 9