Conformation dependence of integrin-type II collagen binding. Inability of collagen peptides to support α2β1 binding, and mediation of adhesion to denatured collagen by a novel α5β1-fibronectin bridge

D. S. Tuckwell, S. Ayad, M. E. Grant, M. Takigawa, M. J. Humphries

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101 Citations (Scopus)

Abstract

The mechanism of interaction of chondrocytic cells with cartilage-specific type II collagen has been examined using HCS-2/8 human chondrosarcoma cells as a model system. By the criteria of specific collagen secretion and integrin expression profile, HCS-2/8 have a similar differentiated phenotype to normal chondrocytes and are therefore a good model system. HCS-2/8 cells were able to attach and spread on both native and heat-denatured pepsinised type II collagen, and assays using denatured cyanogen bromide fragments apparently localised the major cell binding site to the CB10 fragment. However, when they were used as soluble inhibitors, cyanogen bromide fragments were found to block adhesion to denatured collagen, but had no effect on either attachment or spreading on the native molecule. The inability of cyanogen bromide fragments to reproduce the cell binding site of native collagen demonstrated a strict dependence on collagen conformation. This was also reflected in the receptors that were employed by HCS-2/8 cells for binding to type II collagen: binding to native collagen was mediated by the integrin-α2β1 while binding to denatured collagen was mediated by a novel α5β1-fibronectin bridge. The identification of this bridge adds to the mechanisms by which cells can bind to denatured collagens. The previously characterised KDGEA active site peptide from type I collagen was found to be inactive as an inhibitor of type II collagen-mediated adhesion. The implications of these findings for the strategies used to identify adhesive active sites within collagens are discussed. In particular, these data suggest that, unlike other integrin ligands, a synthetic peptide-based approach is not suitable for the identification of collagen active sites.

Original languageEnglish
Pages (from-to)993-1005
Number of pages13
JournalJournal of cell science
Volume107
Issue number4
Publication statusPublished - Jan 1 1994
Externally publishedYes

Keywords

  • Collagen
  • Conformation dependence
  • Fibronectin
  • Integrin

ASJC Scopus subject areas

  • Cell Biology

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