Ligand recognition by the I domain-containing integrins

Cell Mol Life Sci. 1998 Jun;54(6):556-66. doi: 10.1007/s000180050184.


Seven of the integrin alpha subunits described to date, alpha 1, alpha 2, alpha L, alpha X, alpha d, alpha M and alpha E, contain a highly conserved I (or A) domain of approximately 200 amino acid residues inserted near the amino-terminus of the subunit. As the result of a variety of independent experimental approaches, a large body of data has recently accumulated that indicates that the I domains are independent, autonomously folding domains capable of directly binding ligands that play a necessary and important role in ligand binding by the intact integrins. Recent crystallographic studies have elucidated the structures of recombinant alpha M and alpha L I domains and also delineated a novel divalent cation-binding motif within the I domains (metal ion-dependent adhesion site, MIDAS) that appears to mediate the divalent cation binding of the I domains and the I domain-containing integrins to their ligands.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Amino Acid Sequence
  • Cations, Divalent / metabolism
  • Conserved Sequence / genetics
  • Humans
  • Integrins / chemistry*
  • Integrins / physiology
  • Ligands*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding / physiology
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid


  • Cations, Divalent
  • Integrins
  • Ligands