title: S-glutathionylation decreases Mg2+ inhibition and S-nitrosylation enhances Ca2+ activation of RyR1 channels.
abstract: We have analyzed the effects of the endogenous redoxactive agents S-nitrosoglutathione and glutathione disulfide, and the NO donor NOR-3, on calcium release kinetics mediated by ryanodine receptor channels. Incubation of triad-enriched sarcoplasmic reticulum vesicles isolated from mammalian skeletal muscle with these three agents elicits different responses. Glutathione disulfide significantly reduces the inhibitory effect of Mg2+ without altering Ca2+ activation of release kinetics, whereas NOR-3 enhances Ca2+ activation of release kinetics without altering Mg2+ inhibition. Incubation with S-nitrosoglutathione produces both effects; it significantly enhances Ca2+ activation of release kinetics and diminishes the inhibitory effect of Mg2+ on this process. Triad incubation with [35S]nitrosoglutathione at pCa 5 promoted 35S incorporation into 2.5 cysteine residues per channel monomer; this incorporation decreased significantly at pCa 9. These findings indicate that S-nitrosoglutathione supports S-glutathionylation as well as the reported S-nitrosylation of ryanodine receptor channels (Sun, J., Xu, L., Eu, J. P., Stamler, J. S., and Meissner, G. (2003) J. Biol. Chem. 278, 8184-8189). The combined results suggest that S-glutathionylation of specific cysteine residues can modulate channel inhibition by Mg2+, whereas S-nitrosylation of different cysteines can modulate the activation of the channel by Ca2+. Possible physiological and pathological implications of the activation of skeletal Ca2+ release channels by endogenous redox species are discussed.
authors.affiliation: Centro Fondo de Investigación Avanzada en Areas Prioritarias de Estudios Moleculares de la Célula, Facultad de Medicina, Universidad de Chile, Casilla 70005, Santiago 7, Chile.
authors.forename: Paula
authors.initials: P
authors.lastname: Aracena
authors.forename: Gina
authors.initials: G
authors.lastname: Sánchez
authors.forename: Paulina
authors.initials: P
authors.lastname: Donoso
authors.forename: Susan L
authors.initials: SL
authors.lastname: Hamilton
authors.forename: Cecilia
authors.initials: C
authors.lastname: Hidalgo
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005978:Glutathione / Q000378:metabolism*; D007700:Kinetics; D008051:Lipid Bilayers; D008274:Magnesium / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010084:Oxidation-Reduction; D011817:Rabbits; D012433:Ryanodine / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013997:Time Factors
chemical_list: D002352:Carrier Proteins; D004220:Disulfides; D008051:Lipid Bilayers; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; C070048:triadin; D012433:Ryanodine; D005978:Glutathione; D008274:Magnesium; D009584:Nitrogen; D002118:Calcium