Is a promoter of calcium phosphate mineralization, playing a critical role in the formation of the compact, mineralized, aprismatic enamel surface layer during the maturation stage of amelogenesis. Highest expression in the mandible. Found in the basal lamina of maturation stage ameloblasts of incisors and unerupted molars. Also found in the internal basal lamina of junctional epithelium in molars. Expressed in ameloblasts as they undergo post-secretory transition. Expression decreases as ameloblasts progress through maturation. O-glycosylated. Phosphorylated by FAM20C in vitro. Belongs to the amelotin family.