What does calsequestrin do?

Calsequestrin is a calcium-binding protein primarily found in the sarcoplasmic reticulum of muscle cells. Its main function is to store calcium ions, which are crucial for muscle contraction. By regulating calcium levels, calsequestrin helps ensure that calcium is available for release during muscle activation and is also involved in the reuptake of calcium after contraction, thus playing a key role in muscle relaxation.