Neurocan is a heparin binding proteoglycan

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