Integrin a2b1 is the major receptor for collagens in human tissues, being involved in cell adhesion and the control of collagen and collagenase gene expression. The collagen binding site of a2b1 has been localized to the a2 von Willebrand Factor type A (VWFA) domain (A-domain or I-domain) and the residues responsible for the interaction with collagen have been mapped. We report a study of a2 VWFA domain in which residue E318, which lies outside the collagen binding site, is mutated to tryptophan, showing that this is a gain-of-function mutation. .
