[5] Phospholamban is a 52-amino acid integral membrane protein that regulates the calcium (Ca2+) pump in cardiac muscle cells.

When phosphorylated (by PKA) - disinhibition of Ca2+-ATPase of SR leads to faster Ca2+ uptake into the sarcoplasmic reticulum, thereby contributing to the lusitropic response elicited in heart by beta-agonists.

Mutations in this gene are a cause of inherited human dilated cardiomyopathy with refractory congestive heart failure.

[10] Thus, activators of PKA, such as the beta-adrenergic agonist epinephrine (released by sympathetic stimulation), may enhance the rate of cardiac myocyte relaxation.

[12] Mutations in this gene are a cause of inherited human dilated cardiomyopathy with refractory congestive heart failure.