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ATP2A1-3 transport Ca2+ from cytosol to ER lumen (R-HSA-427910) [Homo sapiens]

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Intracellular pools of Ca2+ serve as the source for inositol 1,4,5-trisphosphate (IP3) -induced alterations in cytoplasmic free Ca2+. In most human cells Ca2+ is stored in the lumen of the sarco/endoplastic reticulum by ATPases known as SERCAs (ATP2As). In platelets, ATP2As transport Ca2+ into the platelet dense tubular network. ATP2As are P-type ATPases, similar to the plasma membrane Na+ and Ca+-ATPases. Humans have three genes for SERCA pumps; ATP2A1-3. Studies on ATP2A1 suggest that it binds two Ca2+ ions from the cytoplasm and is subsequently phosphorylated at Asp351 before translocating Ca2+ into the SR lumen. There is a counter transport of two or possibly three protons ensuring partial charge balancing. Sarcolipin (SLN) can reversibly inhibit the activity of ATP2A1 by decreasing the apparent affinity of the ATPase for Ca2+ (Gorski et al. 2013) whereas activated Ca2+/CaM-dependent protein kinase II (CAMK2) and sorcin (SRI) can both stimulate ATP2A1-3 activity (Toyofuku et al. 1994, Matsumoto et al. 2005).

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Compartment endoplasmic reticulum membrane
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PhysicalEntity Activity Active Units
ATP2A1-3 calcium-transporting ATPase activity (0005388)  
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Literature References
pubMedId Title Journal Year
2953725 Ca2+-activated ATPase in microsomes from human liver J Biol Chem 1987
7702581 Localization and identification of Ca2+ATPases in highly purified human platelet plasma and intracellular membranes. Evidence that the monoclonal antibody PL/IM 430 recognizes the SERCA 3 Ca2+ATPase in human platelets Biochem J 1995
23362265 Sarco(endo)plasmic reticulum calcium ATPase (SERCA) inhibition by sarcolipin is encoded in its luminal tail J. Biol. Chem. 2013
7929371 Identification of Ser38 as the site in cardiac sarcoplasmic reticulum Ca(2+)-ATPase that is phosphorylated by Ca2+/calmodulin-dependent protein kinase J. Biol. Chem. 1994
15754088 Sorcin interacts with sarcoplasmic reticulum Ca(2+)-ATPase and modulates excitation-contraction coupling in the heart Basic Res. Cardiol. 2005
Inferred Entries
Orthologous events
 
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