title: Interaction between the enamel matrix proteins amelogenin and ameloblastin.
abstract: Enamel matrix consists of amelogenin and non-amelogenins. Though amelogenin is not involved in nucleation of minerals, the enamel mineralization is impaired when amelogenin or other matrix protein (ameloblastin/enamelin) genes are mutated. We hypothesize that amelogenin may promote enamel mineralization by interacting with the calcium-binding matrix proteins. Specific binding of amelogenin to N-acetylglucosamine (GlcNAc), GlcNAc-mimicking peptides (GMps), and their carrier proteins and the identification of amelogenin-trityrosyl-motif-peptide (ATMP) as a GlcNAc/GMp-binding domain in amelogenin favor the hypothesis. This study tested the interaction of amelogenin with ameloblastin, a carrier of GMp sequence at intermittent sites. Neither GlcNAc nor sialic acids were identified in the recombinant-ameloblastin. Amelogenin bound to recombinant-ameloblastin in both Western blots and in ELISA. More specifically, [(3)H]ATMP bound to both recombinant and native ameloblastins. Dosimetry and Scatchard analyses showed the specific interaction between ATMP and ameloblastin, suggesting that amelogenin may interact with ameloblastin to form a heteromolecular assembly.
authors.affiliation: Center for Craniofacial Molecular Biology, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, USA. rravindr@usc.edu
authors.forename: Hanumanth H
authors.initials: HH
authors.lastname: Ravindranath
authors.forename: Li-Sha
authors.initials: LS
authors.lastname: Chen
authors.forename: Margaret
authors.initials: M
authors.lastname: Zeichner-David
authors.forename: Rieko
authors.initials: R
authors.lastname: Ishima
authors.forename: Rajeswari M H
authors.initials: RM
authors.lastname: Ravindranath
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry*; D053523:Amelogenin; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002113:Calcification, Physiologic; D002352:Carrier Proteins / Q000737:chemistry*; D003743:Dental Enamel / Q000737:chemistry*; D003746:Dental Enamel Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: C490889:AMBN protein, human; D053523:Amelogenin; D002352:Carrier Proteins; D003746:Dental Enamel Proteins; D011994:Recombinant Proteins; C109069:enamel matrix proteins; D000117:Acetylglucosamine