FIGURE 2.

Efficiency of surface expression of full-length and NTD-deleted AMPA receptors in transfected HEK293 cells. A, immunoblot analyses showing the receptor levels on cell surface (top row) and in the total cell extract (center row). Plasma membrane expression was analyzed by using a surface biotinylation assay. The samples were probed by using the appropriate C-terminal domain-specific antibodies. Bottom row, GAPDH immunoreactivity in the same cell extracts, serving as a loading control and for signal normalization. Positions of molecular size markers are shown on the left. B, quantitation of relative surface expression levels. *, p < 0.05; **, p < 0.01; ***, p < 0.001. C, quantitation of relative total expression levels. **, p < 0.01. B and C, data are mean ± S.E. (n = 4) for the full-length and NTD-deleted receptors. The bar graphs correspond to the samples in A.