Calcium ATPase

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PDB Molecule of the Month pdb51_1

Ca2+ ATPase is a form of P-ATPase that transfers calcium after a muscle has contracted. The calcium ATPase are:[1]

  • Plasma membrane Ca2+ ATPase (PMCA)
  • Sarcoplasmic reticulum Ca2+ ATPase (SERCA)

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.[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]

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

  • Active transport#Counter-transport

References

  1. ↑ nlm.nih.gov
  2. ↑ 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.". Brain Research. Developmental Brain Research. 152 (2): 129–136. doi:10.1016/j.devbrainres.2004.06.004. PMID 15351500. 
  3. ↑ 3.0 3.1 3.2 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. 
  4. ↑ Carafoli, E (1991). "Calcium pump of the plasma membrane". Physiological Reviews 71 (1): 129–153. PMID 1986387. Retrieved 2007-01-30. 
  5. ↑ 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. 
  6. ↑ 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 2075377. PMID 17170045. 17170045. Retrieved 2007-01-13. 

External links

3.6.1
3.6.2
3.6.3-4: ATPase
3.6.3
Cu++ (3.6.3.4)
Ca+ (3.6.3.8)
Na+/K+ (3.6.3.9)
H+/K+ (3.6.3.10)
  • ATP4A
Other P-type ATPase
3.6.4
3.6.5: GTPase
3.6.5.1: Heterotrimeric G protein
3.6.5.2: Small GTPase > Ras superfamily
3.6.5.3: Protein-synthesizing GTPase
3.6.5.5-6: Polymerization motors
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      • 2.7.10
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      • 3.1.3.48
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F-, V-, and A-type ATPase (3.A.2)
A-ATPase
found in Archea
P-type ATPase (3.A.3)
  • 3.A.3.1.4: H+/K+ transporting, nongastric: ATP12A
  • Other/ungrouped:
  • Mg++ transporting: ATP3
  • Class I, type 8: ATP8A1
  • ATP8B1
  • ATP8B2
  • ATP8B3
  • ATP8B4
  • Class II, type 9: ATP9A
  • ATP9B
  • Class V, type 10: ATP10A
  • ATP10B
  • ATP10D
  • Class VI, type 11: ATP11A
  • ATP11B
  • ATP11C
  • type 13: ATP13A1
  • ATP13A2
  • ATP13A3
  • ATP13A4
  • ATP13A5

see also ATPase disorders

B memb: cead, trns (1A, 1C, 1F, 2A, 3A1, 3A2-3, 3D), other


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