Matrilin-4 is a widely expressed 73kD member of the Matrilin family of modular extracellular matrix proteins; it associates with collagen fibrils and is thought to link the fibrils with other matrix constituents. Mouse matrilin-4 contains four EGF domains between two von Willebrand Factor-A domain (vWA) domains. A C-terminal alpha-helix/coiled-coil region is often proteolytically removed so that Matrilin-4 is found as a mixture of monomers with dimers and trimers of Matrilin-1, -2 or -4 molecules. Mature mouse Matrilin-4 shows 90% amino acid identity with human Matrilin-4. A short isoform lacks the N-terminal vWA domain.