Anchoring functions of collagen VI I depend on its ability to form homotypic fibrils and to bind to other macromolecules to form heterotypic complexes. Biosensor-based binding assays were employed to analyze the kinetics of the NO domain-mediated binding of collagen VII to laminin 5, collagen IV, and collagen I. We showed that collagen VII interacts with laminin 5 and collagen IV with a K-d value of 10(-9) M. In contrast, the NCl-mediated binding to collagen I was weak with a K-d value of 10(-6) M. Binding assays also showed that the NCl domain Utilizes the same region to bind to both laminin 5 and collagen IV. We postulate that the ability of the NCl domains to bind with high affinities to laminin 5 and collagen IV facilitates stabilization of the structure of the basement membrane itself and that the NCl-collagen I interaction may be less important for stabilization of the dermal-epidermal junction. (c) 2006 Elsevier Inc. All rights reserved.