Transglutaminase-mediated oligomerization promotes osteoblast adhesive properties of osteopontin and bone sialoprotein

Cell Adh Migr. 2011 Jan-Feb;5(1):65-72. doi: 10.4161/cam.5.1.13369. Epub 2011 Jan 1.

Abstract

Tissue transglutaminase (TG2) is a widely distributed, protein-crosslinking enzyme having a prominent role in cell adhesion as a β1 integrin co-receptor for fibronectin. In bone and teeth, its substrates include the matricellular proteins osteopontin (OPN) and bone sialoprotein (BSP). The aim of this study was to examine effects of TG2-mediated crosslinking and oligomerization of OPN and BSP on osteoblast cell adhesion. We show that surfaces coated with oligomerized OPN and BSP promote MC3T3-E1/C4 osteoblastic cell adhesion significantly better than surfaces coated with the monomeric form of the proteins. Both OPN and BSP oligomer-adherent cells showed more cytoplasmic extensions than those cells grown on the monomer-coated surfaces indicative of increased cell connectivity. Our study suggests a role for TG2 in promoting the cell adhesion function of two matricellular substrate proteins prominent in bone, tooth cementum and certain tumors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone and Bones / metabolism
  • Cell Adhesion / physiology
  • Cell Line
  • Dental Cementum / metabolism
  • Fibronectins / metabolism
  • GTP-Binding Proteins / metabolism*
  • Integrin beta1 / metabolism
  • Integrin-Binding Sialoprotein / genetics*
  • Integrin-Binding Sialoprotein / metabolism*
  • Mice
  • Osteoblasts / cytology*
  • Osteoblasts / metabolism
  • Osteopontin / genetics*
  • Osteopontin / metabolism*
  • Protein Binding
  • Protein Glutamine gamma Glutamyltransferase 2
  • Tooth / metabolism
  • Transglutaminases / metabolism*

Substances

  • Fibronectins
  • Integrin beta1
  • Integrin-Binding Sialoprotein
  • Osteopontin
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases
  • GTP-Binding Proteins