The cell-surface glycoprotein vascular cell adhesion molecule-1 (VCAM-1; ref. 1) mediates intercellular adhesion by specific binding to the integrin very-late antigen-4 (VLA-4, alpha 4 beta 1; ref. 3). VCAM-1, with the intercellular adhesion molecules ICAM-1, ICAM-2, ICAM-3 and the mucosal vascular addressin MAd-CAM-1, forms an integrin-binding subgroup of the immunoglobulin superfamily ...
The cell-surface glycoprotein vascular cell adhesion molecule-1 (VCAM-1; ref. 1) mediates intercellular adhesion by specific binding to the integrin very-late antigen-4 (VLA-4, alpha 4 beta 1; ref. 3). VCAM-1, with the intercellular adhesion molecules ICAM-1, ICAM-2, ICAM-3 and the mucosal vascular addressin MAd-CAM-1, forms an integrin-binding subgroup of the immunoglobulin superfamily. In addition to their clinical relevance in inflammation, these molecules act as cellular receptors for viral and parasitic agents. The predominant form of VCAM-1 in vivo has an amino-terminal extracellular region comprising seven immunoglobulin-like domains. Functional studies have identified a conserved integrin-binding motif in domains 1 and 4, variants of which are present in the N-terminal domain of all members of the immunoglobulin superfamily subgroup. We report here the crystal structure of a VLA-4-binding fragment composed of the first two domains of VCAM-1. The integrin-binding motif (Q38IDSPL) is highly exposed and forms the N-terminal region of the loop between beta-strands C and D of domain 1. This motif exhibits a distinctive conformation which we predict will be common to all the integrin-binding IgSF molecules. These, and additional data, map VLA-4 binding to the face of the CFG beta-sheet, the surface previously identified as the site for intercellular adhesive interactions between members of the immunoglobulin superfamily.
Related Citations:
Crystallization and Preliminary X-Ray Diffraction Characterisation of Both a Native and Selenomethionyl Vla-4 Binding Fragment of Vcam-1 Bottomley, M.J., Robinson, R.C., Driscoll, P.C., Harlos, K., Stuart, D.I., Aplin, R.T., Clements, J.M., Jones, E.Y., Dudgeon, T.J. (1994) J Mol Biol 244: 464
Expression and Characterisation of a Very-Late Antigen-4 (Alpha4Beta1) Integrin Binding Fragment of Vascular Cell-Adhesion Molecule-1 Dudgeon, T.J., Bottomley, M.J., Driscoll, P.C., Humphries, M.J., Mould, A.P., Wingfield, G.I., Clements, J.M. (1994) Eur J Biochem 226: 517
Organizational Affiliation:
Laboratory of Molecular Biophysics, Oxford Centre for Molecular Sciences, UK.
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