Different forms of DMP1 play distinct roles in mineralization.
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.
Gericke
A
A
Department of Chemistry, Kent State University, Kent, OH, USA.
Qin
C
C
Sun
Y
Y
Redfern
R
R
Redfern
D
D
Fujimoto
Y
Y
Taleb
H
H
Butler
W T
WT
Boskey
A L
AL
D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D003460:Crystallization; D003804:Dentin / Q000737:chemistry*; D017886:Durapatite / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000502:physiology*; D005782:Gels; D006025:Glycosaminoglycans / Q000378:metabolism; D066298:In Vitro Techniques; D010446:Peptide Fragments / Q000502:physiology; D010750:Phosphoproteins / Q000737:chemistry / Q000502:physiology*; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D051381:Rats; D017550:Spectroscopy, Fourier Transform Infrared
D002135:Calcium-Binding Proteins; C081635:Dmp1 protein, rat; D016326:Extracellular Matrix Proteins; D005782:Gels; D006025:Glycosaminoglycans; D010446:Peptide Fragments; D010750:Phosphoproteins; D017886:Durapatite