Calsequestrin is a high-capacity, low-affinity calcium-binding protein found within the sarcoplasmic reticulum of muscle cells. It plays a crucial role in muscle physiology by regulating calcium ion concentration, which is essential for muscle contraction and relaxation. Calsequestrin is primarily located in the lumen of the sarcoplasmic reticulum, where it can bind up to 50 ions of calcium per molecule.
