Different forms of DMP1 play distinct roles in mineralization

J Dent Res. 2010 Apr;89(4):355-9. doi: 10.1177/0022034510363250. Epub 2010 Mar 3.

Abstract

Dentin matrix protein-1 (DMP1) is a major synthetic product of hypertrophic chondrocytes and osteocytes. Previous in vitro studies showed full-length DMP1 inhibits hydroxyapatite (HA) formation and growth, while its N-terminal fragment (37K) promotes HA formation. Since there are 3 fragments within the mineralized tissues [N-terminal, C-terminal (57K), and a chondroitin-sulfate-linked N-terminal fragment (DMP1-PG)], we predicted that each would have a distinct effect on mineralization related to its interaction with HA. In a gelatin-gel system, 37K and 57K fragments were both promoters of HA formation and growth; DMP1-PG was an inhibitor. The secondary structures of the 3 fragments and the full-length protein in the presence and absence of Ca2+ and HA determined by FTIR showed that the full-length protein undergoes slight conformational changes on binding to HA, while 37K, 57K, and DMP1-PG do not change conformation. These findings indicate that distinct forms of DMP1 may work collectively in controlling the mineralization process.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Calcification, Physiologic / physiology*
  • Calcium-Binding Proteins / metabolism
  • Crystallization
  • Dentin / chemistry*
  • Durapatite / metabolism*
  • Extracellular Matrix Proteins / chemistry
  • Extracellular Matrix Proteins / physiology*
  • Gels
  • Glycosaminoglycans / metabolism
  • In Vitro Techniques
  • Peptide Fragments / physiology
  • Phosphoproteins / chemistry
  • Phosphoproteins / physiology*
  • Protein Processing, Post-Translational
  • Protein Structure, Secondary
  • Rats
  • Spectroscopy, Fourier Transform Infrared

Substances

  • Calcium-Binding Proteins
  • Dmp1 protein, rat
  • Extracellular Matrix Proteins
  • Gels
  • Glycosaminoglycans
  • Peptide Fragments
  • Phosphoproteins
  • Durapatite