title: Localization of plasma membrane and secretory calcium pumps in the mammary gland.
abstract: Until recently the mechanism for the enrichment of milk with calcium was thought to be almost entirely via the secretory pathway. However, recent studies suggest that a plasma membrane calcium ATPase, PMCA2, is the primary mechanism for calcium transport into milk, highlighting a major role for apical calcium transport. We compared the expression of the recently identified secretory calcium ATPase, SPCA2, and SPCA1, in the mouse mammary gland during development. SPCA2 levels increased over 35-fold during lactation with expression localized to luminal secretory cells, while SPCA1 increased only a modest 2-fold and was expressed throughout the cells of the mammary gland. We also observed major differences in the localization of PMCA2 and PMCA1. Our studies highlight the likely specific roles of PMCA2 and SPCA2 in lactation and indicate that calcium transport into milk is a complex interplay between apical and secretory pathways.
authors.affiliation: School of Pharmacy, The University of Queensland, Steele Building, Brisbane, Qld 4072, Australia.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Faddy
authors.forename: Chanel E
authors.initials: CE
authors.lastname: Smart
authors.forename: Ren
authors.initials: R
authors.lastname: Xu
authors.forename: Genee Y
authors.initials: GY
authors.lastname: Lee
authors.forename: Paraic A
authors.initials: PA
authors.lastname: Kenny
authors.forename: Mingye
authors.initials: M
authors.lastname: Feng
authors.forename: Rajini
authors.initials: R
authors.lastname: Rao
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Brown
authors.forename: Mina J
authors.initials: MJ
authors.lastname: Bissell
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Roberts-Thomson
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Monteith
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D005260:Female; D007774:Lactation / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000201:enzymology* / Q000254:growth & development*; D051379:Mice; D008892:Milk / Q000378:metabolism; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000032:analysis / Q000235:genetics / Q000378:metabolism
chemical_list: D053499:Plasma Membrane Calcium-Transporting ATPases; C452183:ATP2C2 protein, human; C506954:Atp2b1 protein, mouse; C506959:Atp2b2 protein, mouse; C492024:Atp2c1 protein, mouse; D000252:Calcium-Transporting ATPases; D002118:Calcium