Neurocan is a heparin binding proteoglycan

Neurocan and brevican are related chondroitin sulfate proteoglycans which are mainly expressed in the central nervous system. Neurocan and the secreted brevican variant are composed of globular N-terminal hyaluronan binding domains, central O-linked oligosaccharide attachment regions, and globular C-terminal domains. Interaction studies of mouse brain proteoglycans revealed that neurocan, but not brevican, was retained on a heparin affinity matrix. Also a recombinantly produced C-terminal fragment of neurocan, expressed by HEK 293 cells, was retained by the heparin affinity matrix. The substitution of this fragment with a chondroitin sulfate chain did not inhibit binding to the heparin affinity matrix at physiological NaCl concentrations, but decreased the NaCl concentration necessary for elution. Two potential consequences of the heparin binding ability of neurocan are an enforcement of the interaction with other heparin binding molecules and a directed secretion by polarized cells. (C) 2000 Academic Press.