Cyclic GMP-dependent protein kinase phosphorylates phospholamban in isolated sarcoplasmic reticulum from cardiac and smooth muscle.
Phospholamban of isolated sarcoplasmic reticulum of cardiac and smooth muscle is phosphorylated by cyclic GMP-dependent protein kinase (G-kinase). Concomitantly, the affinity of the Ca2+ pump for Ca2+ is increased. These effects are very similar to those seen with cyclic AMP-dependent protein kinase (A-kinase). The phosphate incorporation into phospholamban and the stimulatory effects of both kinases on the Ca2+ pump are not additive, suggesting that G-kinase phosphorylates the same serine residue as A-kinase. A possible physiological role for phosphorylation of phospholamban by G-kinase is discussed.
Raeymaekers
L
L
Laboratory of Physiology, University of Leuven, Belgium.
Hofmann
F
F
Casteels
R
R
D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002417:Cattle; D006152:Cyclic GMP / Q000494:pharmacology; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D007527:Isoenzymes / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D013552:Swine; D000099211:Phospholamban
D002118:Calcium; D002135:Calcium-Binding Proteins; D006152:Cyclic GMP; D007527:Isoenzymes; D011494:Protein Kinases; D000099211:Phospholamban