Ca2+-dependent K+ permeability of heart sarcolemmal vesicles. Modulation by cAMP-dependent protein kinase activity and by calmodulin.
The Ca2+-dependent K+ permeability of heart sarcolemma vesicles was measured by following the transmembrane movement of the charge compensating tetraphenylborate anion. The increase in vesicles permeability induced by Ca2+ is lost when membrane proteins are dephosphorylated by an endogenous protein phosphatase and is restored by a phosphorylation process catalysed by a cAMP-dependent protein kinase. The calmodulin antagonist R 24571 lowers the Ca2+-dependent K+ permeability by decreasing the Ca2+ affinity of the K+ transporting system.
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000502:physiology*; D002417:Cattle; D002463:Cell Membrane Permeability; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010766:Phosphorylation; D011188:Potassium / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism*; D013775:Tetraphenylborate / Q000378:metabolism
D002147:Calmodulin; D007473:Ion Channels; D008565:Membrane Proteins; D013775:Tetraphenylborate; D011494:Protein Kinases; D011188:Potassium; D002118:Calcium