Fig. 4. Lecticans inhibit the interaction between TN-R and contactin 1. (A-F) COS7 cells expressing contactin 1 on their surface were incubated with contactin-1-coated microspheres in (A) the absence or (B-F) the presence of TN-R (10 µg/ml), and with (C) aggrecan (20 µg/ml), (D) brevican, (E) neurocan or (F) chondroitinase-ABC-treated aggrecan (20 µg/ml). Double fluorescence images obtained with a confocal microscope are shown. The left panels reveal expression of contactin 1 by indirect immunofluorescence. The right panels depict binding of contactin-1-coated microspheres in the same microscopic field. Bar, 100 µm. TN-R-mediated molecular-bridge formation between contactin 1 polypeptides is blocked by aggrecan and other lecticans. (G) Schematic illustration of the sandwich binding assay performed in the presence of TN-R and aggrecan.