Matrix Gla protein C-terminal region binds to vitronectin. Co-localization suggests binding occurs during tissue development

Matrix Biol. 2005 Aug;24(5):353-61. doi: 10.1016/j.matbio.2005.05.004.

Abstract

Matrix Gla protein (MGP) regulates calcification in cartilage and arteries. MGP synthesis during embryonic development and its binding and regulation of growth factors and morphogens of the TGF-beta/BMP superfamily suggests that it has additional functions. Assay by far-western gel overlays and gel filtration shift shows MGP binds vitronectin. Binding is saturable and consistent with a single class of binding sites. MGP binds to vitronectin but not collagen, fibromodulin, heparin, osteocalcin, chondroitin sulfate, laminin, ovalbumin or albumin. We have identified a vitronectin binding site within a 17-amino acid peptide 61-77 near the carboxyl-terminus that corresponds to a naturally occurring MGP C-terminus. MGP and the 61-77 MGP peptide also binds to fibronectin. MGP and vitronectin are focally co-localized in embryonic tissues. Co-localization in vivo suggests that the MGP and vitronectin interactions may modify cell-matrix interactions. Alternatively, vitronectin-bound MGP may have altered function for modulating BMP2 or TGF-beta activity. The current study demonstrates that MGP has a novel binding activity for vitronectin, an extracellular protein that promotes cell-matrix interactions and regulates coagulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Calcium-Binding Proteins / chemistry*
  • Calcium-Binding Proteins / metabolism*
  • Cartilage
  • Cattle
  • Dose-Response Relationship, Drug
  • Embryonic Development*
  • Extracellular Matrix Proteins / chemistry*
  • Extracellular Matrix Proteins / metabolism*
  • Fibronectins
  • Humans
  • Kidney
  • Protein Binding
  • Rats
  • Reproducibility of Results
  • Vitronectin / metabolism*

Substances

  • Calcium-Binding Proteins
  • Extracellular Matrix Proteins
  • Fibronectins
  • Vitronectin
  • matrix Gla protein