Calcium ATPase

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Calcium ATPase
Calcium ATPase[1]
EC number
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum

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)[edit]

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)[edit]

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[edit]


  1. ^ PDB Molecule of the Month Calcium pump
  2. ^
  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. PMID 15351500. doi:10.1016/j.devbrainres.2004.06.004. 
  4. ^ a b c 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. PMC 2075377Freely accessible. PMID 17170045. doi:10.1113/jphysiol.2006.123901. 17170045. Archived from the original on September 27, 2007. Retrieved 2007-01-13. 

External links[edit]