The family of P-type Ca2+-transport ATPases is made up of three subfamilies: sarco(endo)plasmic-reticulum Ca2+ ATPases (SERCA), plasma- membrane Ca2+ ATPases (PMCA), and secretory-pathway Ca2+ ATPases (SPCA). The SPCA1 protein (encoded for by the ATP2C1 gene) is a Ca2+/ Mn2+-transport ATPase. It localizes to the Golgi apparatus and, together with SERCA2, it is responsible for the ionic milieu in the Golgi lumen. SPCA2 (encoded by the ATP2C2 gene) also localizes to the golgi apparatus and has a higher enzymatic turnover rate than that of SPCA1 while having a high affinity for cytosolic Ca2+. The enzymatic properties of the human SPCA2 enzyme and the restriction of its tissue expression to the gastrointestinal and respiratory tracts, prostate, thyroid, salivary, and mammary glands may, in principle ,define a Ca2+-ATPase pump with a specific physiological role in secretory cells.