Dental epithelium proliferation and differentiation regulated by ameloblastin

Abstract

The principal components of the enamel matrix that are synthesized by secretory ameloblasts can be classified into two major categories, amelogenin and nonamelogenis, which includes ameloblastin (AMBN) and enamelin. AMBN is an enamel matrix protein that regulates cell adhesion, proliferation, and differentiation of ameloblasts. In AMBN-deficient mice, ameloblasts are detached from the enamel matrix, continue to proliferate, and form a multiple cell layer; often, odontogenic tumors develop in the maxilla with age. AMBN had heparin-binding domains at the C-terminal half and that these domains were critical for AMBN binding to dental epithelial cells. Overexpression of full-length AMBN protein inhibited proliferation of human ameloblastoma cells, but overexpression of heparin-binding-domains-deficient AMBN protein had no inhibitory effect. AMBN promotes cell binding through the heparin-binding sites and plays an important role in preventing odontogenic tumor development by suppressing cell proliferation and maintaining differentiation phenotype.