title: Interaction between hydrogen sulfide-induced sulfhydration and tyrosine nitration in the KATP channel complex.
abstract: Hydrogen sulfide (H₂S) is an endogenous gaseous mediator affecting many physiological and pathophysiological conditions. Enhanced expression of H2S and reactive nitrogen/oxygen species (RNS/ROS) during inflammation alters cellular excitability via modulation of ion channel function. Sulfhydration of cysteine residues and tyrosine nitration are the posttranslational modifications induced by H₂S and RNS, respectively. The objective of this study was to define the interaction between tyrosine nitration and cysteine sulfhydration within the ATP-sensitive K(+) (KATP) channel complex, a significant target in experimental colitis. A modified biotin switch assay was performed to determine sulfhydration of the KATP channel subunits, Kir6.1, sulphonylurea 2B (SUR2B), and nitrotyrosine measured by immunoblot. NaHS (a donor of H₂S) significantly enhanced sulfhydration of SUR2B but not Kir6.1 subunit. 3-Morpholinosydnonimine (SIN-1) (a donor of peroxynitrite) induced nitration of Kir6.1 subunit but not SUR2B. Pretreatment with NaHS reduced the nitration of Kir6.1 by SIN-1 in Chinese hamster ovary cells cotransfected with the two subunits, as well as in enteric glia. Two specific mutations within SUR2B, C24S, and C1455S prevented sulfhydration by NaHS, and these mutations prevented NaHS-induced reduction in tyrosine nitration of Kir6.1. NaHS also reversed peroxynitrite-induced inhibition of smooth muscle contraction. These studies suggest that posttranslational modifications of the two subunits of the KATP channel interact to alter channel function. The studies described herein demonstrate a unique mechanism by which sulfhydration of one subunit modifies tyrosine nitration of another subunit within the same channel complex. This interaction provides a mechanistic insight on the protective effects of H₂S in inflammation.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Minho
authors.initials: M
authors.lastname: Kang
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hashimoto
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Aravind
authors.initials: A
authors.lastname: Gade
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia hiakbarali@vcu.edu.
authors.forename: Hamid I
authors.initials: HI
authors.lastname: Akbarali
mesh_terms: D000818:Animals; D016466:CHO Cells; D002122:Calcium Chloride / Q000494:pharmacology; D003412:Cricetulus; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007082:Ileum / Q000187:drug effects / Q000378:metabolism*; D054086:KATP Channels / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008981:Molsidomine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000378:metabolism; D009154:Mutation; D030421:Peroxynitrous Acid / Q000737:chemistry*; D011499:Protein Processing, Post-Translational; D015398:Signal Transduction; D013440:Sulfides / Q000737:chemistry* / Q000494:pharmacology; D064233:Sulfonylurea Receptors / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: C577511:Abcc9 protein, mouse; D054086:KATP Channels; D013440:Sulfides; D064233:Sulfonylurea Receptors; C092520:uK-ATP-1 potassium channel; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; C002385:linsidomine; D008981:Molsidomine; C025451:sodium bisulfide; D003545:Cysteine; D002122:Calcium Chloride
keywords: colon; hydrogen sulfide; inflammation; ion channels; nitration