Calbindin28kDa and Calmodulin are Hyperabundant in Rat Dental Enamel Cells: Identification of the Protein Phosphatase Calcineurin as a Principal Calmodulin Target and of a Secretion‐Related Role for Calbindin28kDa

Abstract

Enamel cells are likely to experience heavy demands for intracellular calcium homeostasis during the secretion and hypermineralization of dental enamel. Here, the two major high‐affinity calcium‐binding proteins in rat enamel epithelium were identified as calbindin2gkDa and calmodulin, using a microscale approach. Both proteins were hyperabundant, totalling up to 2% of the soluble protein and surpassing the amounts in cerebellum, the benchmark tissue. Calbindin28kDa and calmodulin accounted for 26% of the total calcium‐binding capacity in enamel cell cytosol, under near physiological conditions. Numerous calmodulin‐binding proteins were detected with an overlay assay, indicating that calmodu..