Τίτλος:
Hydrogen sulfide inhibits Kir2 and Kir3 channels by decreasing sensitivity to the phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2)
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Inwardly rectifying potassium (Kir) channels establish and regulate the resting membrane potential of excitable cells in the heart, brain, and other peripheral tissues. Phosphatidylinositol 4,5-bisphosphate (PIP2) is a key direct activator of ion channels, including Kir channels. The gasotransmitter carbon monoxide has been shown to regulate Kir channel activity by altering channel–PIP2 interactions. Here, we tested in two cellular models the effects and mechanism of action of another gasotransmitter, hydrogen sulfide (H2S), thought to play a key role in cellular responses under ischemic conditions. Direct administration of sodium hydrogen sulfide as an exogenous H2S source and expression of cystathionine -lyase, a key enzyme that produces endogenous H2S in specific brain tissues, resulted in comparable current inhibition of several Kir2 and Kir3 channels. This effect resulted from changes in channel-gating kinetics rather than in conductance or cell-surface localization. The extent of H2S regulation depended on the strength of the channel–PIP2 interactions. H2S regulation was attenuated when channel–PIP2 interactions were strengthened and was increased when channel–PIP2 interactions were weakened by depleting PIP2 levels. These H2S effects required specific cytoplasmic cysteine residues in Kir3.2 channels. Mutation of these residues abolished H2S inhibition, and reintroduction of specific cysteine residues back into the background of the cytoplasmic cysteine-lacking mutant rescued H2S inhibition. Molecular dynamics simulation experiments provided mechanistic insights into how potential sulfhydration of specific cysteine residues could lead to changes in channel–PIP2 interactions and channel gating. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.
Συγγραφείς:
Ha, J.
Xu, Y.
Kawano, T.
Hendon, T.
Baki, L.
Garai, S.
Papapetropoulos, A.
Thakur, G.A.
Plant, L.D.
Logothetis, D.E.
Περιοδικό:
Journal of Biological Chemistry
Εκδότης:
American Society for Biochemistry and Molecular Biology Inc.
Λέξεις-κλειδιά:
Amino acids; Carbon monoxide; Cell membranes; Cell proliferation; Enzyme inhibition; Histology; Molecular dynamics; Phospholipids; Sodium sulfide; Sulfur compounds; Sulfur determination; Tissue, Cellular response; Cysteine residues; Ischemic conditions; Mechanism of action; Membrane potentials; Molecular dynamics simulations; Peripheral tissue; Phosphatidylinositol 4 ,5-Bisphosphate, Hydrogen sulfide, 3 mercaptopyruvate sulfurtransferase; cystathionine beta synthase; cystathionine gamma lyase; cysteine; hydrogen sulfide; inwardly rectifying potassium channel; inwardly rectifying potassium channel subunit Kir2; inwardly rectifying potassium channel subunit Kir3; inwardly rectifying potassium channel subunit Kir3.2; phosphatidylinositol 4,5 bisphosphate; unclassified drug; cystathionine gamma lyase; fusion protein; G protein coupled inwardly rectifying potassium channel; hydrogen sulfide; inwardly rectifying potassium channel; phosphatidylinositol 4,5 bisphosphate; recombinant protein; sodium bisulfide; sulfide, animal cell; apoptosis; Article; brain region; cell surface; cellular distribution; channel gating; controlled study; enzyme inhibition; enzyme kinetics; enzyme synthesis; hippocampus; nerve cell; nitrosylation; nonhuman; oocyte; oxidative stress; priority journal; protein expression; protein interaction; protein phosphorylation; Xenopus; allosterism; amino acid substitution; animal; antagonists and inhibitors; chemistry; CHO cell line; Cricetulus; cytology; drug effect; genetics; metabolism; molecular dynamics; molecular model; mouse; mutation; patch clamp technique; protein conformation; site directed mutagenesis; Xenopus laevis, Allosteric Regulation; Amino Acid Substitution; Animals; CHO Cells; Cricetulus; Cystathionine gamma-Lyase; G Protein-Coupled Inwardly-Rectifying Potassium Channels; Hydrogen Sulfide; Mice; Models, Molecular; Molecular Dynamics Simulation; Mutagenesis, Site-Directed; Mutation; Oocytes; Patch-Clamp Techniques; Phosphatidylinositol 4,5-Diphosphate; Potassium Channels, Inwardly Rectifying; Protein Conformation; Recombinant Fusion Proteins; Recombinant Proteins; Sulfides; Xenopus laevis
DOI:
10.1074/jbc.RA117.001679
