Cyclic AMP-dependent protein kinase and Ca2+-calmodulin stimulate the formation of polyphosphoinositides in a sarcoplasmic reticulum preparation of rabbit heart.
A rabbit heart membrane fraction enriched in sarcoplasmic reticulum was incubated in a reaction mixture containing [gamma-32P]ATP. The catalytic subunit of cyclic AMP-dependent protein kinase enhanced the 32P-labelling of both phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-bisphosphate. Ca2 +-calmodulin also increased the 32P-incorporation into both polyphosphoinositides. Upon SDS gel-electrophoretic analysis of the membrane proteins, phospholamban was found to be concurrently phosphorylated by the exogenous catalytic subunit as well as by an endogenous Ca2+-calmodulin-dependent protein kinase.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002147:Calmodulin / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000494:pharmacology*; D009206:Myocardium / Q000378:metabolism*; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000096:biosynthesis*; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011494:Protein Kinases / Q000494:pharmacology*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D000099211:Phospholamban
D002118:Calcium; D002135:Calcium-Binding Proteins; D002147:Calmodulin; D000242:Cyclic AMP; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D010761:Phosphorus Radioisotopes; D011494:Protein Kinases; D000099211:Phospholamban; C037178:phosphatidylinositol 4-phosphate