Secretory pathway Ca2+/Mn2+-ATPase isoform 2 and lactation: specific localization of plasmalemmal and secretory pathway Ca2+ pump isoforms in the mammary gland

Journal Article · Wed Apr 09 04:00:00 EDT 2008 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/j.bbrc.2008.03.003· OSTI ID:939484

Faddy, Helen M; Smart, Chanel E; Xu, Ren; Lee, Genee Y; Kenny, Paraic A; Feng, Mingye; Rao, Rajini; Brown, Melissa A; Bissell, Mina J; Roberts-Thomson, Sarah J; Monteith, Gregory R

The supply of calcium to the developing neonate via milk is an important physiological process. Until recently the mechanism for the enrichment of milk with calcium was thought to be almost entirely mediated via the secretory pathway. However, recent studies suggest that a specific isoform of the 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 different stages of development. SPCA2 levels increased over 35 fold during lactation, while SPCA1 increased only a modest two fold. The potential importance of SPCA2 in lactation was also highlighted by its localization to luminal secretory cells of the mammary gland during lactation, while SPCA1 was expressed throughout the cells of the mammary gland. We also observed major differences in the localization of PMCA2 and PMCA1 during lactation. Using the SCp2 mouse mammary epithelial cell 3D culture model, differences in the sub-cellular distribution of PMCA2 and PMCA1 were clear. These studies highlight the likely specific roles of PMCA2 and SPCA2 in lactation, and link the recently characterized SPCA2 calcium pump to the supply of calcium into milk and the regulation of Golgi resident enzymes important in lactation. They also indicate that calcium transport into milk is a complex interplay between apical and secretory pathways.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Life Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 939484
• Report Number(s): LBNL-211E
• Journal Information: Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 3 Vol. 369; ISSN BBRCA9; ISSN 0006-291X
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AVAILABILITY
CALCIUM
DISTRIBUTION
ENZYMES
LACTATION
MAMMARY GLANDS
MEMBRANES
MILK
NEONATES
PHENOBARBITAL
PLASMA
REGULATIONS
TRANSPORT
calcium pump isoforms mammary gland