Integrin alpha 2 I-domain is a binding site for collagens

D Tuckwell, D A Calderwood, L J Green, M J Humphries

Research output: Contribution to journalArticlepeer-review


Integrins alpha 1 beta 1 and alpha 2 beta 1 are major cellular receptors for collagens. The alpha 1 and alpha 2 subunits contain a approximately 200 amino acid inserted domain (I-domain) in their N-terminal region and, because of the homology between the I-domains and the collagen-binding A-domains of von Willebrand factor, it has been suggested that the I-domains might mediate the collagen-binding functions of alpha 1 beta 1 and alpha 2 beta 1. In order to fully investigate this hypothesis, we have generated recombinant human alpha 2 I-domain (r alpha 2I) by reverse transcriptase-polymerase chain reaction/bacterial expression and tested its ability to mediate the collagen-binding functions of alpha 2 beta 1. R alpha 2 I binds specifically to type I collagen in a concentration-dependent manner: binding is cation dependent and, like the complete receptor, is supported by magnesium and manganese ions but not by calcium ions. R alpha 2I is recognised by anti-functional anti-alpha 2 monoclonal antibodies 6F1, 5E8 and P1E6 in capture ELISAs, and anti-functional antibodies inhibited r alpha 2I-collagen binding. In addition, r alpha 2I inhibits cell spreading on collagen. R alpha 2I is therefore a collagen-binding domain and can account for many of the collagen-binding functions of integrin alpha 2 beta 1. We have also determined the collagen specificity of r alpha 2I and found that it binds types I, II and XI collagen.

Original languageEnglish
Pages (from-to)1629-37
Number of pages9
JournalJournal of Cell Science
Volume108 ( Pt 4)
Publication statusPublished - Apr 1995


  • Animals
  • Antigens, CD
  • Base Sequence
  • Cations, Divalent
  • Cloning, Molecular
  • Collagen
  • DNA Primers
  • Escherichia coli
  • Female
  • Humans
  • Integrin alpha1beta1
  • Integrin alpha2
  • Integrins
  • Kinetics
  • Molecular Sequence Data
  • Placenta
  • Polymerase Chain Reaction
  • Pregnancy
  • Rats
  • Receptors, Collagen
  • Recombinant Proteins


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