Extracellular processing of dentin matrix protein in the mineralizing odontoblast culture

Satoyoshi, Masanori; Koizumi, Tadahiko; Teranaka, Toshio; Iwamoto, T; Takita, Hiroko; Kuboki, Yoshinori; Saito, Shigeru; Mikuni-Takagaki, Yuko

doi:10.1007/bf00310265

Cited by 27 publications

(18 citation statements)

References 25 publications

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“…Furthermore, the regulatory effects of inhibitors and activators are similarly dependent upon the substrate S/T environment. Because of these subtle substrate effects, determination of which constitutive kinase activity is involved in any particular instance can best be defined by operational use of specific peptide substrates, such as RRREEETEEE (CK2) Satoyoshi et al (1995), andSuzuki et al (1996) , 1995. ) bone or dentin ECM molecules which remained associated with the ECM surrounding the nodules.…”

Section: (C) Other Bone Ncpsmentioning

confidence: 99%

Phosphorylation of the Proteins of the Extracellular Matrix of Mineralized Tissues By Casein Kinase-Like Activity

Veis

Sfeir

1997

Critical Reviews in Oral Biology & Medicine

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The extracellular matrix of the connective tissue contains non-collagenous proteins (NCP) which are acidic in character. The NCP of mineralizing systems (bone, dentin) differ from those of the non-mineralizing systems (skin, tendon) in that the mineralized tissue NCP are frequently phosphorylated. The phosphorylated proteins have been implicated in various aspects of the mineralization process. Thus, it is of interest to consider the mechanism and regulation of phosphorylation of the major matrix NCP. The majority of the phosphorylation takes place at Ser or Thr residues embedded within acidic sequences, and therefore are targets for casein kinase I (CKI ) or casein kinase 11 (CK2)-like kinases. CKI and CK2 are distantly related members of the protein kinase family. They are ubiquitous, constitutively active, second-messenger-independent kinases. CKI is found in a variety of isoforms, all homologous to the cx-subunit of the protein kinase family. It acts as a monomer. The active form of CK2 is a tetrameric holoenzyme, with 2 cx catalytic subunits and 2 ( regulatory subunits. The CK2 ac has activity alone, but the holoenzyme is four-to five-fold that activity. CK2 can use either ATP or GTP as the phosphate donor, but CK 1 can use only ATP. The CK2 activity which phosphorylates the mineralized tissue NCP appears to be localized to membraneassociated cell fractions, and is present in the endoplasmic reticulum and Golgi compartments in osteoblasts, where phosphorylation of the secreted proteins appears to take place as co-and post-translational processes. Data Bone and dentin are tissues in which mineral deposits of carbonate apatite form in an orderly fashion within a pre-formed collagen fibril matrix. Structural studies clearly show that the majority of the mineral phase is composed of carbonate-apatite crystals, whose crystal c-axes are aligned with the fibril axes of the collagen fibrils (FittonJackson, 1957;Glimcher and Krane, 1968;Glimcher, 1976;Weiner and Traub, 1986;Arsenault, 1988;Arsenault et al, 1991;Landis et al., 1992). Although much of the early work attempted to show that the collagen fibrils were responsible for the placement and induction of mineral deposition, this proposition was never verified. Instead, attention began to focus on the non-collagenous protein components of the matrix (Herring and Kent, 1963;Schlueter and Veis, 1964;Veis and Schlueter, 1964;Spector and Glimcher, 1972;Veis et al., 1972;Glimcher, 1976), especially since it was recognized that, as a class, the non-collagenous extracellular proteins (NCP) shared a common char360Crit Rev Oral Biol Med 8(4)

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Section: (C) Other Bone Ncpsmentioning

confidence: 99%

Phosphorylation of the Proteins of the Extracellular Matrix of Mineralized Tissues By Casein Kinase-Like Activity

Veis

Sfeir

1997

Critical Reviews in Oral Biology & Medicine

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“…They are different both in their morphology with extensively developed cell processes and in the loss of high-level alkaline phosphatase. Regarding the development of these cells, it was suggested that the matrix phosphoproteins are post-translationally processed extracellularly into more phosphorylated forms which, we believe, facilitate mineralization (MikuniTakagaki et al, 1995;Satoyoshi et al, 1995). The purpose of this study was to determine the sites of enzymatic phosphorylation of matrix proteins and the process that may lead the matrix to mineralize by histochemical means.…”

Section: Introductionmentioning

confidence: 97%

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confidence: 99%

In situ Phosphorylation of Bone and Dentin Proteins by the Casein Kinase II-like Enzyme

Suzuki¹,

Yamaguchi

Ikeda

et al. 1998

J Dent Res

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Our previous studies suggested the possibility of extracellular phosphorylation of matrix phosphoproteins into more phosphorylated forms by mature odontoblasts and osteocytes (Mikuni-Takagi et al., 1995; Satoyoshi et al., 1995). To elucidate such phosphorylation of bone and dentin proteins, we developed a histochemical method using frozen sections to determine the sites of enzymatic processing by the casein kinase II-like enzyme. It was observed that proteins in bone, dentin, and predentin are phosphorylated by the endogenous enzyme when the tissue slices were incubated with [gamma-32P] GTP, suggesting that there are both substrates and the enzyme in these matrices. In vivo, phosphate donors, ATP and GTP, may be supplied through dentinal canals and osteocyte canaliculi. Immunohistochemical analysis of frozen sections showed that the extremely intense staining of phosphoserine residues by anti-phosphoserine antibodies appeared in dentin only after demineralization of the tissue samples. It implies that these phosphoserine residues become bound to mineral as soon as the phosphorylation is completed, thereby being inaccessible to the antibodies without demineralization. The data support our notion that the extracellular phosphorylation of dentin/bone proteins, regulated by the developmental stages of bone and dentin cells, occurs prior to matrix mineralization.

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“…The formation of epithelial-mesenchymal nodules showing mineralizing areas within agregation of cells, described as odontoblast-like, suggested that the cultured cells were able to maintain the potential to reorganize into odontogenic tissues in vitro. Isolated cells from pulp/papilla mesenchyme in the absence of epithelial components, including explant cultures, primary and subcultured cells cloned from enzymatically dissociated rat [6][7][8][9], mouse [10], bovine [11][12][13][14], and human [15][16][17][18][19][20][21] tissues were also used. Transformed cell lines were also selected from mouse [22,23] and human [24] pulp mesenchymes.…”

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confidence: 99%

Odontoblast Differentiation of Human Dental Pulp Cells in Explant Cultures

et al. 2000

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In order to elucidate the mechanisms involved in human dentin formation, we developed a cell culture system to promote differentiation of dental pulp cells into odontoblasts. Explants from human teeth were cultured in Eagle's basal medium supplemented with 10% or 15% fetal calf serum, with or without beta-glycerophosphate (beta GP). Addition of beta GP to the culture medium induced odontoblast features in the cultured pulp cells. Cells polarized and some of them exhibited a typical cellular extension. In some cases, cells aligned with their processes oriented in the same direction and developed junctional complexes similar to the terminal web linking odontoblasts in vivo. Fine structural analyses showed the presence of typical intracellular organelles of the odontoblast body, whereas the process contained only cytoskeleton elements and secretory vesicles. Polarized cells deposited onto the plastic dishes an abundant and organized type I collagen-rich matrix with areas of mineralization appearing thereafter. X-ray microanalysis showed the presence of calcium and phosphorus and the electron diffraction pattern confirmed the apatitic crystal structure of the mineral. High expression of alpha 1 (1) collagen mRNAs was detected in all polarized cells whereas dentin sialoprotein gene was mainly expressed in mineralizing areas. This cell culture system allowed for the differentiation of pulp cells into odontoblasts, at both the morphological and functional level. Moreover, these cells presented a spatial organization similar to the odontoblastic layer.

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Extracellular processing of dentin matrix protein in the mineralizing odontoblast culture

Cited by 27 publications

References 25 publications

Phosphorylation of the Proteins of the Extracellular Matrix of Mineralized Tissues By Casein Kinase-Like Activity

Phosphorylation of the Proteins of the Extracellular Matrix of Mineralized Tissues By Casein Kinase-Like Activity

In situ Phosphorylation of Bone and Dentin Proteins by the Casein Kinase II-like Enzyme

Odontoblast Differentiation of Human Dental Pulp Cells in Explant Cultures

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