Type VII collagen specifically binds fibronectin via a unique subdomain within the collagenous triple helix

Type VII collagen is the major component of anchoring fibrils, structures within basement membranes beneath stratified squamous epithelium thought to mediate the adherence of the epidermis to the dermis of human skin. Type VII collagen has affinity for fibronectin. The interaction between type VII collagen and fibronectin is mediated through the collagen-binding domain on the amino terminus of fibronectin. Heretofore, the domain on the type VII collagen molecule that binds to fibronectin was not known. In this study, we mapped the binding site of fibronectin to a specific subdomain of the triple helical collagenous region of type VII collagen, immediately adjacent to the small carboxyl terminal non-collagenous domain. This fibronectin-binding site within the type VII collagen molecule lies between nucleotide residues 615 and 1161.