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Phospholamban

Meaning

Phospholamban, often abbreviated as PLN, is a small, regulatory protein found predominantly in the sarcoplasmic reticulum of cardiac and skeletal muscle cells. Its primary physiological function is to inhibit the Sarco/Endoplasmic Reticulum Ca²⁺-ATPase (SERCA) pump, thereby modulating the rate at which calcium is sequestered back into the sarcoplasmic reticulum. The phosphorylation status of Phospholamban is a critical determinant of myocardial contractility, directly influencing the heart’s ability to relax and contract effectively. Genetic mutations or dysregulation of this protein are often implicated in various forms of heart failure.