Formation of a supramolecular complex is involved in the reconstitution of basement membrane components

Abstract

Basement membrane macromolecules, including type-IV collagen, laminin and heparan sulfate proteoglycan, do not aggregate when incubated alone. Precipitation occurs in the presence of equimolar amounts of laminin and type-IV collagen but variable amounts of heparan sulfate proteoglycan. This interaction requires native laminin and type-IV collagen. Heparan sulfate proteoglycan increases the precipitation of laminin particularly in the presence of type-IV collagen. Fibronectin does not cause type-IV collagen to precipitate. Components of basement membrane interact in a highly specific manner. Such interactions may be involved in the deposition of basement membrane in situ.