Regulatory role of phospholamban in the efficiency of cardiac sarcoplasmic reticulum Ca2+ transport
Phospholamban is an inhibitor of the sarcoplasmic reticulum Ca2+ transport apparent affinity for Ca2+ in cardiac muscle. This inhibitory effect of phospholamban can be relieved through its phosphorylation or ablation. To better characterize the regulatory mechanism of phospholamban, we examined the initial rates of Ca2+-uptake and Ca2+-ATPase activity under identical conditions, using sarcoplasmic