Reactome: A Curated Pathway Database

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

Species Homo sapiens

Summation

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.

Locations in the PathwayBrowser
Additional Information
Compartment endoplasmic reticulum membrane
Components of this entry
Input entries
Output entries
Catalyst Activity
PhysicalEntity Activity Active Units
ATP2A1-3 calcium-transporting ATPase activity (0005388)
This entry is regulated by
Regulation type Name
NegativeRegulation
PositiveRegulation