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Extracellular processing of bone and dentin proteins in matrix mineralization
Y Suzuki1, T Kubota, T Koizumi
1Department of Oral Biochemistry, Kanagawa Dental College, Yokosuka, Japan.
Connective Tissue Research
|January 1, 1996
Summary
Bone and dentin mineralization involves matrix deposition followed by mineral formation. Extracellular phosphorylation by a casein kinase II (CKII)-like enzyme is crucial for bone and dentin mineralization.
Area of Science:
- Biochemistry
- Cell Biology
- Mineralization
Background:
- Bone and dentin mineralization occurs in two stages: matrix synthesis by osteoblasts/odontoblasts and subsequent mineral deposition.
- Mineralization occurs distant from the cells, suggesting extracellular processes are key.
Purpose of the Study:
- To elucidate the sequence of events in matrix-mediated bone and dentin mineralization.
- To identify the enzyme responsible for extracellular phosphorylation in these tissues.
Main Methods:
- In situ phosphorylation experiments using [gamma-32P] GTP.
- Analysis of post-translational and extracellular processing of phosphoproteins.
Main Results:
- Phosphoproteins in bone and dentin undergo limited proteolysis and extracellular phosphorylation.
- Evidence suggests a casein kinase II (CKII)-like enzyme mediates extracellular phosphorylation.
- This enzyme is responsible for phosphorylating key proteins like dentin phosphophoryn and bone sialoproteins.
Conclusions:
- Extracellular phosphorylation by a CKII-like enzyme is a critical step in bone and dentin mineralization.
- This process enhances the mineral-binding capacity of phosphoproteins, facilitating matrix mineralization.