Calcium ATPase is a form of P-ATPase that transfers calcium after a muscle has contracted. The calcium ATPase are[1]:
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The plasma membrane Ca2+ ATPase (PMCA) is a transport protein in the plasma membrane of cells that serves to remove calcium (Ca2+) from the cell. It is vital for regulating the amount of Ca2+ within cells.[2] In fact, the PMCA is involved in removing Ca2+ from all eukaryotic cells.[3] There is a very large transmembrane electrochemical gradient of Ca2+ driving the entry of the ion into cells, yet it is very important for cells to maintain low concentrations of Ca2+ for proper cell signalling; thus it is necessary for the cell to employ ion pumps to remove the Ca2+.[4] The PMCA and the sodium calcium exchanger (NCX) are together the main regulators of intracellular Ca2+ concentrations.[3] Since it transports Ca2+ into the extracellular space, the PMCA is also an important regulator of the calcium concentration in the extracellular space.[5]
The PMCA belongs to a family of P-type primary ion transport ATPases that form an aspartyl phosphate intermediate.[3]
The PMCA is expressed in a variety of tissues, including the brain.[6]
SERCA resides in the sarcoplasmic reticulum (SR) within muscle cells. It is a Ca2+ ATPase that transfers Ca2+ from the cytosol of the cell to the lumen of the SR at the expense of ATP hydrolysis during muscle relaxation.
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