title: The coordination of S-sulfhydration, S-nitrosylation, and phosphorylation of endothelial nitric oxide synthase by hydrogen sulfide.
abstract: The gasotransmitter hydrogen sulfide (H(2)S), which is generated by cystathionine γ-lyase (CSE), signals by modifying proteins through S-sulfhydration and potentially other mechanisms. A target protein for H(2)S is endothelial nitric oxide synthase (eNOS), an enzyme that generates nitric oxide (NO), which causes vasodilation. We investigated whether H(2)S-induced S-sulfhydration affected the S-nitrosylation and phosphorylation of eNOS and the functional effects of changes in these posttranslational modifications on eNOS activity. In vitro, different NO donors induced the S-nitrosylation of eNOS without affecting its S-sulfhydration, whereas the H(2)S donor sodium hydrosulfide (NaHS) decreased the S-nitrosylation of eNOS. Cys(443) was the primary S-sulfhydration site in eNOS and was one site that could be S-nitrosylated. Phosphorylation increases eNOS activity. Although exposure of eNOS-expressing HEK-293 cells to NaHS or vascular endothelial growth factor (VEGF) triggered the phosphorylation of wild-type and C443G-eNOS, VEGF did not affect the S-sulfhydration of eNOS and a mutant of eNOS that could not be phosphorylated was still S-sulfhydrated. eNOS can be present in cells in monomeric or dimeric form, but only eNOS dimers produce NO. In wild-type mice, eNOS proteins were predominantly dimerized, whereas eNOS from CSE-knockout (KO) mice, S-nitrosylated eNOS, and heterologously expressed C443G-eNOS was mostly monomeric. Accordingly, basal production of NO was lower in CSE-KO endothelial cells than in wild-type endothelial cells. Our data suggest that H(2)S increases eNOS activity by inducing the S-sulfhydration of eNOS, promoting its phosphorylation, inhibiting its S-nitrosylation, and increasing eNOS dimerization, whereas NO decreases eNOS activity by promoting the formation of eNOS monomers.
authors.affiliation: Department of Biology, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada. Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Altaany
authors.affiliation: Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada. The School of Kinesiology, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada.
authors.forename: YoungJun
authors.initials: Y
authors.lastname: Ju
authors.affiliation: Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada. The School of Kinesiology, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada.
authors.forename: Guangdong
authors.initials: G
authors.lastname: Yang
authors.affiliation: Department of Biology, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada. Cardiovascular and Metabolic Research Unit, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada. rwang@lakeheadu.ca.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
mesh_terms: D006862:Hydrogen Sulfide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D009603:Nitroso Compounds / Q000378:metabolism*; D018384:Oxidative Stress; D010766:Phosphorylation
chemical_list: D009603:Nitroso Compounds; D052250:Nitric Oxide Synthase Type III; D006862:Hydrogen Sulfide