Evidence for a Ca2+ channel within the ryanodine receptor complex from cardiac sarcoplasmic reticulum.
The solubilized [3H]ryanodine receptor from cardiac sarcoplasmic reticulum was centrifuged through linear sucrose gradients. A single peak of radioactivity with apparent sedimentation coefficient of approximately 30S specifically comigrated with a high molecular weight protein of apparent relative molecular mass approximately 400,000. Incorporation of the ryanodine receptor into lipid bilayers induced single Ca2+ channel currents with conductance and kinetic behavior almost identical to that of native cardiac Ca2+ release channels. These results suggest that the cardiac ryanodine receptor comprises the Ca2+ release channel involved in excitation-contraction coupling in cardiac muscle.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D007473:Ion Channels / Q000032:analysis*; D008970:Molecular Weight; D009206:Myocardium / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000032:analysis*; D019837:Ryanodine Receptor Calcium Release Channel; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D007473:Ion Channels; D011950:Receptors, Cholinergic; D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium