Calcium ATPase is an enzyme that helps transport calcium ions across cell membranes. It uses energy from the breakdown of ATP (adenosine triphosphate) to move calcium out of cells or into the sarcoplasmic reticulum in muscle cells. This process is crucial for regulating calcium levels, which are important for various cellular functions, including muscle contraction and neurotransmitter release. There are different types of calcium ATPases, such as SERCA (Sarcoplasmic Reticulum Calcium ATPase) and PMCA (Plasma Membrane Calcium ATPase). Each type plays a specific role in maintaining calcium homeostasis in different tissues. Proper functioning of calcium ATPases is essential for overall cellular health and activity.