Different forms of DMP1 play distinct roles in mineralization.
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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.
author list (cited authors)
Gericke, A., Qin, C., Sun, Y., Redfern, R., Redfern, D., Fujimoto, Y., ... Boskey, A. L.
complete list of authors
Gericke, A||Qin, C||Sun, Y||Redfern, R||Redfern, D||Fujimoto, Y||Taleb, H||Butler, WT||Boskey, AL