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Removal of Mg 2+ inhibition of cardiac ryanodine receptor by palmitoyl coenzyme A
Author(s) -
Connelly Timothy,
Ahern Christopher,
Sukhareva Manana,
Coronado Roberto
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00969-4
Subject(s) - ryanodine receptor , endoplasmic reticulum , cardiac muscle , coenzyme a , chemistry , ryanodine receptor 2 , palmitic acid , receptor , biochemistry , cofactor , biophysics , fatty acid , endocrinology , biology , enzyme , reductase
45 Ca 2+ fluxes and planar bilayer recordings indicated that the fatty acid metabolise palmitoyl coenzyme A, but not free coenzyme A or palmitic acid, stimulated the cardiac ryanodine receptor channel of pig heart sarcoplasmic reticulum. Palmitoyl CoA reactivated channels inhibited by concentrations of cytoplasmic free Mg 2+ in the physiological range. Reactivation by palmitoyl CoA in the presence of Mg 2+ was stimulated by myoplasmic free Ca 2+ in the micromolar range. Acyl coenzyme A derivatives may be utilized by cardiac muscle cells to compensate for the severe Mg 2+ inhibition of ryanodine receptors which would otherwise leave Ca 2+ stores unresponsive to Ca 2+ and to other cytosolic ligands involved in signal transduction.