FIGURE 3.
Confocal microscopy showing cell surface presented α3-containing GABAA receptors. HEK293 cells were transfected with expression vectors for α3(I) or (M), β2, and γ2L subunits in the ratio 1.2:10:0.5. A, cell surface distributed α3(I) visualized in nonpermeabilized cells using an α3 antibody and a TRITC-conjugated secondary antibody. The phase contrast image of the cells is shown on the right. B, cell surface distribution of the α3(M) subunits as in A. The scale bars represent 10 μm. C, the relative reduction in fluorescence intensity of α3(M) from the experiments in A and B as described under “Experimental Procedures” with the rate of α3(I) normalized to 1 (n = 3). **, p < 0.01. The values reported are the means ± 95% CI. D, HEK293 cells transfected with: empty vector, β2, and γ2L (lane C); α3(I), β2, and γ2L (lane α3(I)); and α3(M), β2, and γ2L (lane α3(M)). The transfected cells were incubated with sulfo-NHS-SS-biotin, and the biotinylated proteins were analyzed by Western blot. The cell surface bound transferrin receptors was detected and used as a loading control.