The Membrane-spanning Proteoglycan NG2 Binds to Collagens V and VI through the Central Nonglobular Domain of Its Core Protein

摘要: NG2 is a membrane-spanning proteoglycan with primary structure unique among cell surface or extracellular matrix proteins. To characterize the interaction between and proteins, we have used eukaryotic expression system to produce purify several recombinant fragments covering not only entire ectodomain of but also distinct subdomains molecule. Using solid phase binding assay various identified two main ligands for NG2, namely, collagens V VI. Consistent previous models glycosaminoglycan attachment, roughly 50% containing central domain chondroitin sulfate chains attached protein core. These are directly involved in collagen binding, since chondroitinase-treated exhibit an unimpaired ability bind both collagens. more restricted mapped site NG2. Electron microscopy after rotary shadowing native molecules indicates that this extended nonglobular provides flexible connection joining N- C-terminal globular regions Rotary mixtures VI confirms direct align region giving appearance rod globules.