title: Dentin sialophosphoprotein and dentin matrix protein-1: Two highly phosphorylated proteins in mineralized tissues.
abstract: Dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) are highly phosphorylated proteins that belong to the family of small integrin-binding ligand N-linked glycoproteins (SIBLINGs), and are essential for proper development of hard tissues such as teeth and bones. In order to understand how they contribute to tissue organization, DSPP and DMP-1 have been analyzed for over a decade using both in vivo and in vitro techniques. Among the five SIBLINGs, the DSPP and DMP-1 genes are located next to each other and their gene and protein structures are most similar. In this review we examine the phenotypes of the genetically engineered mouse models of DSPP and DMP-1 and also introduce complementary in vitro studies into the molecular mechanisms underlying these phenotypes. DSPP affects the mineralization of dentin more profoundly than DMP-1. In contrast, DMP-1 significantly affects bone mineralization and importantly controls serum phosphate levels by regulating serum FGF-23 levels, whereas DSPP does not show any systemic effects. DMP-1 activates integrin signalling and is endocytosed into the cytoplasm whereupon it is translocated to the nucleus. In contrast, DSPP only activates integrin-dependent signalling. Thus it is now clear that both DSPP and DMP-1 contribute to hard tissue mineralization and the tissues affected by each are different presumably as a result of their different expression levels. In fact, in comparison with DMP-1, the functional analysis of cell signalling by DSPP remains relatively unexplored.
authors.affiliation: Department of Dental Science for Health Promotion, Division of Cervico-Gnathostomatology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan. suzukis@hiroshima-u.ac.jp
authors.forename: Shigeki
authors.initials: S
authors.lastname: Suzuki
authors.forename: Naoto
authors.initials: N
authors.lastname: Haruyama
authors.forename: Fusanori
authors.initials: F
authors.lastname: Nishimura
authors.forename: Ashok B
authors.initials: AB
authors.lastname: Kulkarni
mesh_terms: D000818:Animals; D001846:Bone Development / Q000502:physiology; D002113:Calcification, Physiologic / Q000502:physiology; D003810:Dentinogenesis / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000502:physiology*; D000089703:Fibroblast Growth Factor-23; D051379:Mice; D008822:Mice, Transgenic; D023421:Models, Animal; D009805:Odontogenesis / Q000502:physiology; D010641:Phenotype; D010750:Phosphoproteins / Q000502:physiology*; D012795:Sialoglycoproteins / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D000099311:Dentin Sialophosphoprotein
chemical_list: D016326:Extracellular Matrix Proteins; D000089703:Fibroblast Growth Factor-23; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C513308:Dmp1 protein, mouse; C000717428:Fgf23 protein, mouse