Purification and characterization of integrin alpha 9 beta 1

Exp Cell Res. 1994 Jul;213(1):183-90. doi: 10.1006/excr.1994.1189.


A new beta 1-containing integrin was isolated from rat liver by affinity chromatography on Sepharose conjugated with the peptide GRGDSPC. The interaction was weakened but not abolished when the arginine and/or aspartic acid in the peptide were replaced with lysine and glutamic acid, respectively. In contrast, the cysteine was necessary for binding of the integrin. The beta 1-associated protein, referred to as alpha 9, had an N-terminal amino acid sequence related to but distinct from previously described integrin alpha-subunits. In addition, an internal peptide sequence was obtained which confirmed that the protein is a new member of the family of integrin alpha-subunits. An antiserum raised against a synthetic peptide corresponding to amino acids 1-16 of alpha 9 reacted specifically with this protein and was used to identify alpha 9 in several tissues. The integrin alpha 9 beta 1 was not retained on Sepharose conjugated with Englebreth-Holm-Swarm tumor (EHS)-laminin, collagen type I, or a 105-kDa cell-binding fragment of fibronectin. However, it did bind specifically to EHS-laminin and collagen type I adsorbed to plastic microtiter wells. The sites of the interactions were localized to fragment E8 of EHS-laminin and to cyanogen bromide fragment 8 of collagen alpha 1(I) and were not inhibited by soluble RGD-containing peptides. The results indicate that alpha 9 beta 1 is a widely distributed laminin/collagen receptor which may have additional, yet unidentified ligands.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Chromatography, Affinity
  • Collagen / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Fibronectins / metabolism
  • Humans
  • Integrins / chemistry
  • Integrins / isolation & purification*
  • Integrins / metabolism
  • Kidney / metabolism
  • Laminin / metabolism
  • Liver / metabolism*
  • Molecular Sequence Data
  • Molecular Weight
  • Muscles / metabolism
  • Myocardium / metabolism
  • Oligopeptides
  • Organ Specificity
  • Protein Binding
  • Rats
  • Receptors, Collagen
  • Receptors, Laminin / chemistry
  • Receptors, Laminin / isolation & purification*
  • Receptors, Laminin / metabolism
  • Sequence Homology, Amino Acid
  • Spleen / metabolism
  • Tumor Cells, Cultured


  • Fibronectins
  • Integrins
  • Laminin
  • Oligopeptides
  • Receptors, Collagen
  • Receptors, Laminin
  • Collagen