Plasma membrane Ca2+ ATPase

The plasma membrane Ca²⁺ ATPase (PMCA) is a transport protein in the plasma membrane of cells that functions as a calcium pump to remove calcium (Ca²⁺) from the cell. PMCA function is vital for regulating the amount of Ca²⁺ within all eukaryotic cells. There is a very large transmembrane electrochemical gradient of Ca²⁺ driving the entry of the ion into cells, yet it is very important that they maintain low concentrations of Ca²⁺ for proper cell signalling. Thus, it is necessary for cells to employ ion pumps to remove the Ca²⁺. The PMCA and the sodium calcium exchanger (NCX) are together the main regulators of intracellular Ca²⁺ concentrations. Since it transports Ca²⁺ into the extracellular space, the PMCA is also an important regulator of the calcium concentration in the extracellular space.

PMCAs belong to the family of P-type primary ion transport ATPases which form aspartyl phosphate intermediates.

Various forms of PMCA are expressed in different tissues, including the brain.