Interactions with tenascin and differential effects on cell adhesion of neurocan and phosphacan, two major chondroitin sulfate proteoglycans of nervous tissue.

摘要: We have studied interactions of tenascin with two chondroitin sulfate proteoglycans, neurocan and phosphacan. Neurocan is a multi-domain proteoglycan 136-kDa core protein that synthesized by neurons binds to hyaluronic acid, whereas the 173-kDa phosphacan, which glia, represents an extracellular variant receptor-type tyrosine phosphatase RPTP zeta/beta. Keratan sulfate-containing glycoforms phosphacan (designated phosphacan-KS) are also present in brain. Immunocytochemical studies early postnatal rat cerebellum demonstrated localization neurocan, phosphacan-KS all overlap extensively tenascin, matrix modulates cell adhesion migration. Binding using purified proteins covalently attached fluorescent microbeads proteoglycan-coated beads co-aggregated differently fluorescing coated tenascin. The co-aggregation was specifically inhibited Fab' fragments antibodies against or proteoglycans soluble A solid phase radioligand binding assay confirmed bind but not laminin fibronectin. Chondroitinase treatment addition free had no significant effect, indicating activity mediated largely via glycoproteins. Scatchard analysis high affinity 125I-phosphacan, phosphacan-KS, single site various 125I-phosphacan In adsorbed Petri dishes, C6 glioma cells effect. Our results suggest vivo between may play important roles nervous tissue histogenesis, possibly modulating signal transduction across plasma membrane.