Calcium ATPase

Calcium ATPase

Calcium ATPase[1]
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MetaCyc metabolic pathway
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Ca2+ ATPase is a form of P-ATPase that transfers calcium after a muscle has contracted. The two kinds of calcium ATPase are:[2]

Plasma membrane Ca2+ ATPase (PMCA)

Rendered image of the Ca2+ pump

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.[3] In fact, the PMCA is involved in removing Ca2+ from all eukaryotic cells.[4] 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+.[5] The PMCA and the sodium calcium exchanger (NCX) are together the main regulators of intracellular Ca2+ concentrations.[4] Since it transports Ca2+ into the extracellular space, the PMCA is also an important regulator of the calcium concentration in the extracellular space.[6]

The PMCA belongs to a family of P-type primary ion transport ATPases that form an aspartyl phosphate intermediate.[4]

The PMCA is expressed in a variety of tissues, including the brain.[7]

Sarcoplasmic reticulum Ca2+ ATPase (SERCA)

Main article: SERCA

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.

See also


  1. PDB Molecule of the Month Calcium pump
  3. Jensen, TP; Buckby LE; Empson RM (2004). "Expression of plasma membrane Ca2+ ATPase family members and associated synaptic proteins in acute and cultured organotypic hippocampal slices from rat". Developmental Brain Research. 152 (2): 129–136. doi:10.1016/j.devbrainres.2004.06.004. PMID 15351500.
  4. 1 2 3 Strehler, EE; Zacharias DA (2001). "Role of alternative splicing in generating isoform diversity among plasma membrane calcium pumps". Physiological Reviews. American Physiological Society. 81 (1): 21–50. PMID 11152753. Retrieved 2007-01-30.
  5. Carafoli, E (1991). "Calcium pump of the plasma membrane". Physiological Reviews. 71 (1): 129–153. PMID 1986387. Retrieved 2007-01-30.
  6. Talarico Jr, EF; Kennedy BG; Marfurt CF; Loeffler KU; Mangini NJ (2005). "Expression and immunolocalization of plasma membrane calcium ATPase isoforms in human corneal epithelium". Molecular Vision. 11: 169–178. PMID 15765049.
  7. Jensen, TP; Filoteo A; Knopfel T; Empson RM (2006). "Pre-synaptic plasma membrane Ca2+ ATPase isoform 2a regulates excitatory synaptic transmission in rat hippocampal CA3". Journal of Physiology. 579 (Pt 1): Published online ahead of print. doi:10.1113/jphysiol.2006.123901. PMC 2075377Freely accessible. PMID 17170045. 17170045. Archived from the original on September 27, 2007. Retrieved 2007-01-13.

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