title: Cyclic nucleotide dependent phosphorylation of neuronal nitric oxide synthase inhibits catalytic activity.
abstract: We have examined the regulation of neuronal nitric oxide synthase (NOS) by phosphorylation with cyclic-GMP (PKG) and cyclic-AMP-dependent (PKA) protein kinases. In vitro phosphorylation studies indicate that both PKG and PKA phosphorylate NOS on a single site. Phosphoamino-acid analysis and peptide mapping demonstrate that phosphorylation by either cyclic-nucleotide kinase occurs on a similar serine residue. Phosphorylation of purified NOS by either PKG or PKA diminishes catalytic activity. Stimulation by 8-Br-cGMP of HEK-293 cells stably transfected with the cDNA for neuronal NOS (293.NOS cells) results in phosphorylation of immunoprecipitated NOS. Incubation of 293-NOS cells with 8-bromo-cGMP or dibutyryl-cAMP reduces nitrite release in response to stimulation with calcium ionophore A23187. Phosphorylation-induced decreases in NOS activity may counterbalance and modulate NOS activating signals.
authors.affiliation: Department of Medicine (Division of Cardiology), Johns Hopkins University School of Medicine, Baltimore, MD 21205.
authors.forename: J L
authors.initials: JL
authors.lastname: Dinerman
authors.forename: J P
authors.initials: JP
authors.lastname: Steiner
authors.forename: T M
authors.initials: TM
authors.lastname: Dawson
authors.forename: V
authors.initials: V
authors.lastname: Dawson
authors.forename: S H
authors.initials: SH
authors.lastname: Snyder
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D002384:Catalysis; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000502:physiology*; D006152:Cyclic GMP / Q000502:physiology*; D004586:Electrophoresis; D006801:Humans; D009474:Neurons / Q000201:enzymology*; D009566:Nitrates / Q000378:metabolism; D019001:Nitric Oxide Synthase; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism
chemical_list: D009566:Nitrates; D010748:Phosphopeptides; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D011494:Protein Kinases; D006152:Cyclic GMP