Key regulator of striated muscle performance by acting as the major Ca(2+) ATPase responsible for the reuptake of cytosolic Ca(2+) into the sarcoplasmic reticulum. Catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic 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). Reversibly inhibited by phospholamban (PLN) at low calcium concentrations (By similarity). Dephosphorylated PLN decreases the apparent affinity of the ATPase for calcium. This inhibition is regulated by the phosphorylation of PLN (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). Interacts VMP1 (By similarity). Skeletal muscle, fast twitch muscle (type II) fibers. Increased contractile activity leads to a decrease in SERCA1 expression, while decreased contractile activity leads to an increase in SERCA1 expression. Ca(2+) and ATP binding cause major rearrangements of the cytoplasmic and transmembrane domains. According to the E1-E2 model, Ca(2+) binding to the cytosolic domain of the pump in the high-affinity E1 conformation is followed by the ATP-dependent phosphorylation of the active site Asp, giving rise to E1P. A conformational change of the phosphoenzyme gives rise to the low-affinity E2P state that exposes the Ca(2+) ions to the lumenal side and promotes Ca(2+) release. Dephosphorylation of the active site Asp mediates the subsequent return to the E1 conformation. PLN and SLN both have a single transmembrane helix; both occupy a similar binding site on ATP2A1 that is situated between the ATP2A1 transmembrane helices. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IIA subfamily.