Expression of plasma membrane Ca++ pump epitopes parallels the progression of enamel and dentin mineralization in rat incisor.

Abstract

We investigated the expression of Ca++ pump epitopes during enamel and dentin mineralization in the rat incisor. Secretory and maturation ameloblasts were studied as well as odontoblasts, using a monoclonal antibody (5F10) against human erythrocyte plasma membrane Ca++, Mg(++)-ATPase. A progressive increase in staining intensity in ameloblasts and the odontoblasts was observed beginning with the onset of mineralization. The mainly membrane-related labeling of ameloblasts showed variable intensity depending on the stage of enamel formation, whereas that of the odontoblasts showed even intensity during continued dentinogenesis. Staining of papillary cells was evident only during enamel maturation. Western blot analysis of freeze-dried ameloblasts was also used to determine the molecular weight of the Ca++ pump epitopes as well as the distribution and relative concentration of epitopes at each stage. An immunoreactive band of MW 140 KD and lower molecular weight bands that are more intense in late than in early maturation were demonstrated. Our studies suggest that the expression of plasma membrane Ca++ pump parallels the progression of mineralization in rat incisor enamel and dentin.

Mitochondrial ATP synthase F1‐β‐subunit is a calcium‐binding protein

“…The observed up-regulation and abundance of the FI-13-subunit (2.7% of soluble protein) during enamel maturation is consistent with other evidence indicating that the calcium homeostatic burden [15,16], calcium transport [38] and expression levels of the plasma membrane calcium pump [39] are maximal at this time. However, the particular roles (e.g.…”

Ion transporters in secretory and cyclically modulating ameloblasts: a new hypothesis for cellular control of preeruptive enamel maturation

“…Expression of Na ϩ -HCO 3 Ϫ transporters in enamel organ. In the stage of enamel secretion, the most peripheral cells of the enamel organ exhibited positive staining reaction for the electrogenic Na ϩ -HCO 3 Ϫ cotransporter NBCe1 but with a decreasing gradient of expression toward the stratum intermedium (Fig.…”

Plasma Membrane Ca²⁺ Pump: Recent Developments

“…For example, in mineralization of rat teeth, the Ca2+ pump epitopes appear in paral lel with the progression of mineralization [45], An immunocytochemical study in smooth muscle showed localization of the Ca2+ pump to the caveolae, suggesting that these invaginations of the plasma membrane play a special role in Ca2* transport [46]. An in situ hybridization study of rat isoforms 1, 2 and 3 showed that each isoform had a distinct distribution in rat brain [47], There was a more than 20-fold difference in reactivity be tween the most reactive portion of the brain and the least reactive portion, suggesting high ly specialized involvement of this Ca2+ pump in brain function.…”