Catalyzes the hydrolysis of ATP coupled with the transport of calcium from the cytoplasm to the extracellular space thereby maintaining intracellular calcium homeostasis. Plays a role in blood pressure regulation through regulation of intracellular calcium concentration and nitric oxide production leading to regulation of vascular smooth muscle cells vasoconstriction. Positively regulates bone mineralization through absorption of calcium from the intestine. Plays dual roles in osteoclast differentiation and survival by regulating RANKL-induced calcium oscillations in preosteoclasts and mediating calcium extrusion in mature osteoclasts (By similarity). Regulates insulin sensitivity through calcium/calmodulin signaling pathway by regulating AKT1 activation and NOS3 activation in endothelial cells (PubMed:29104511).
The ATPase is phosphorylated only at this site by the cAMP-dependent protein kinase, and the phosphorylation is inhibited by calmodulin. The effect of the phosphorylation is to decrease the Km for Ca2+ of the purified ATPase from about 10 microM to about 1.4 microM and to increase the Vmax of ATP hydrolysis about 2-fold.