This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the transport of calcium. ATP + Ca(2+)(in) + H2O = ADP + Ca(2+)(out) + H(+) + phosphate Interacts with SclA and SclB. Colocalizes with SclA and SclB at the sarcoplasmic reticulum and the diad, a structure composed of a single t-tubule paired with a terminal cisterna of the sarcoplasmic reticulum. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family.