Description
Product Characteristics:
The Sarco(endo)plasmic-reticulum (SER) regulatory protein, Phospholamban (PLB), is a small, plasma membrane-associated protein found in the SER of cardiac, smooth and slow-twitch muscle. Believed to assemble into a pentamer, PLB regulates cardiac contractility and Ca2+ affinity for cardiac SER Ca2+ ATPase (SERCA2a). Non-phosphorylated PLB associates with SERCA2a, and inhibits Ca2+ reuptake into the SER. PLB activation occurs when key Serine/Threonine residues in PLB (Ser-10, Ser-16, Thr-17) are phosphorylated by numerous effectors, which include PKC, PKA, PKG, and CaM kinase. Phosphorylation of PLB causes dissociation from SERCA2a and a subsequent increase in the rate of Ca2+ reuptake into the SER, which accelerates ventricular relaxation.
Subcellular location: Cytoplasm, Cell membrane
Synonyms: Cardiac phospholamban, CMD1P, PLB, PLN, PPLA_HUMAN.
Target Information: The protein encoded by this gene is found as a pentamer and is a major substrate for the cAMP-dependent protein kinase in cardiac muscle. The encoded protein is an inhibitor of cardiac muscle sarcoplasmic reticulum Ca(2+)-ATPase in the unphosphorylated state, but inhibition is relieved upon phosphorylation of the protein. The subsequent activation of the Ca(2+) pump leads to enhanced muscle relaxation rates, thereby contributing to the inotropic response elicited in heart by beta-agonists. The encoded protein is a key regulator of cardiac diastolic function. Mutations in this gene are a cause of inherited human dilated cardiomyopathy with refractory congestive heart failure. [provided by RefSeq, Jul 2008]