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What is Function of Phospholamban is: and explain in detail?
Phospholamban is a protein constituent of the sarcoplasmic reticulum of the cardiac muscle. Phosphorylation of phospholamban is responsible for the calcium uptake from the sarcoplasmic reticulum and consequent relaxation of the muscle. Beta adrenergic stimulation increases the rate of contraction and rate of relaxation. The increase in rate of contraction is due to increase in calcium influx consequent upon the cAMP dependent phosphorylation of sarcolemmal channel proteins. The increase rate of relaxation is due to increased rate of calcium uptake by sarcoplasmic reticulum consequent upon phosphorylation of phospholamban. Ref: Understanding Medical Physiology: A Textbook for Medical Students By R. L. Bijlani, S. Manjunatha page 182.