FIGURE 6.

HNK-1 glyco-epitope enhances the surface expression of GluR2 in an N-cadherin-dependent and -independent manner. A, CHO cells were overexpressed with GluR2, N-cadherin, and HNK-1-synthesizing enzymes as indicated. The cell surface proteins on CHO cells were biotinylated, and biotinylated GluR2 molecules were precipitated with streptavidin beads and immunoblotted with anti-GluR2 antibody (Surface GluR2). The overexpressed GluR2 (Total GluR2) or N-cadherin in each cell lysate was almost equivalent. The HNK-1 epitope was expressed on GluR2 when GlcAT-P and HNK-1ST were overexpressed. B, quantification of the surface expression of GluR2 in A. The intensity of surface GluR2 was normalized to total GluR2, and the bar graph shows the percentages compared with control cells (n = 5). *, p < 0.05 (two-tailed t test). Error bars indicate S.E.