Intracellular calcium levels are tightly regulated by an array of transport proteins and channels. The main mechanisms include: - Calcium pumps (such as the Ca²âº-ATPase) that move calcium out of the cell or into the endoplasmic reticulum. - Calcium channels that allow the influx of calcium from the extracellular space or release from internal stores. - Calcium-binding proteins that buffer and modulate calcium levels within the cell.
