This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the transport of calcium. Transports calcium ions from the cytosol into the sarcoplasmic/endoplasmic reticulum lumen. Contributes to calcium sequestration involved in muscular excitation/contraction. ATP + Ca(2+)(in) + H2O = ADP + Ca(2+)(out) + H(+) + phosphate Inhibited by sarcolipin (SLN), phospholamban (PLN) and myoregulin (MRLN) (By similarity). Enhanced by DWORF; DWORF increases activity by displacing sarcolipin (SLN), phospholamban (PLN) and myoregulin (MRLN) (By similarity). Interacts with sarcolipin (SLN) (By similarity). Interacts with phospholamban (PLN) (By similarity). Interacts with myoregulin (MRLN). Interacts with DWORF (By similarity). Found in spleen, lung, intestine and brain. Down-regulated by 1,25-dihydroxyvitamin D3. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IIA subfamily.