Direct regulatory effect of cholesterol on the calmodulin stimulated calcium pump of cardiac sarcolemma.
A great controversy has been set for several years related to an indirect versus a direct effect of cholesterol upon the muscle calcium pump. Employing an enriched cardiac sarcolemma preparation and a (Ca2+, Mg2+)-ATPase fraction isolated from this preparation, this study demonstrates that cholesterol directly interacts with the sarcolemmal calcium pump importantly inhibiting its enzyme activity. It was discovered that this inhibition can be in part explained by a total sensitivity loss of the pump to calmodulin. These results can be considered of importance in the correlation of plasma membrane cholesterol levels with deficiencies in calcium transport and cardiac muscle cell damage.
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology*; D002784:Cholesterol / Q000494:pharmacology*; D002852:Chromatography, Ion Exchange; D007700:Kinetics; D009206:Myocardium / Q000201:enzymology; D010743:Phospholipids / Q000494:pharmacology; D011817:Rabbits; D012508:Sarcolemma / Q000201:enzymology*
D002147:Calmodulin; D010743:Phospholipids; D002784:Cholesterol; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases