title: Cellular uptake of amelogenin, and its localization to CD63, and Lamp1-positive vesicles.
abstract: Proteins of the developing enamel matrix include amelogenin, ameloblastin and enamelin. Of these three proteins amelogenin predominates. Protein-protein interactions are likely to occur at the ameloblast Tomes' processes between membrane-bound proteins and secreted enamel matrix proteins. Such protein-protein interactions could be associated with cell signaling or endocytosis. CD63 and Lamp1 are ubiquitously expressed, are lysosomal integral membrane proteins, and localize to the plasma membrane. CD63 and Lamp1 interact with amelogenin in vitro. In this study our objective was to study the molecular events of intercellular trafficking of an exogenous source of amelogenin, and related this movement to the spatiotemporal expression of CD63 and Lamp1 using various cell lineages. Exogenously added amelogenin moves rapidly into the cell into established Lamp1-positive vesicles that subsequently localize to the perinuclear region. These data indicate a possible mechanism by which amelogenin, or degraded amelogenin peptides, are removed from the extracellular matrix during enamel formation and maturation.
authors.affiliation: Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, Los Angeles, CA 90033-1004, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Shapiro
authors.forename: X
authors.initials: X
authors.lastname: Wen
authors.forename: C T
authors.initials: CT
authors.lastname: Okamoto
authors.forename: H J
authors.initials: HJ
authors.lastname: Wang
authors.forename: S P
authors.initials: SP
authors.lastname: Lyngstadaas
authors.forename: M
authors.initials: M
authors.lastname: Goldberg
authors.forename: M L
authors.initials: ML
authors.lastname: Snead
authors.forename: M L
authors.initials: ML
authors.lastname: Paine
mesh_terms: D000566:Amelogenesis / Q000502:physiology*; D053523:Amelogenin / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D002460:Cell Line; D017931:DNA Primers; D004285:Dogs; D005455:Fluorescent Antibody Technique; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins; D006801:Humans; D007150:Immunohistochemistry; D052118:Lysosomal-Associated Membrane Protein 1 / Q000378:metabolism*; D051379:Mice; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D060149:Tetraspanin 30; D022161:Transport Vesicles / Q000378:metabolism*
chemical_list: D053523:Amelogenin; D015703:Antigens, CD; C554586:CD63 protein, human; C554587:Cd63 protein, mouse; D017931:DNA Primers; D052118:Lysosomal-Associated Membrane Protein 1; D010980:Platelet Membrane Glycoproteins; D060149:Tetraspanin 30; D049452:Green Fluorescent Proteins