Fig. 6.

Blocking CaMKII did not affect the expression levels of GABA_B1a(K->R) mutants. Neurons were transfected with HA-tagged wild-type GABA_B1a or HA-tagged GABA_B1a (K->R) mutants along with GABA_B2 and tested for cell surface expression of GABA_B1 and GABA_B2 after treating the neurons with 10 μM KN93 for 7.5 min. Left, representative images of untreated neurons (control, left panels) and of neurons treated with KN93 (right panels, scale bar 5 μm). The corresponding graphs show the quantification of fluorescence signals. The fluorescence intensity of neurons transfected with wild-type GABA_B1 from untreated neurons (control) was set to 100%. The data represent the mean ± SD of 45–60 neurons per experimental condition derived from three independent experiments. Please note that the considerably lower increase in GABA_B2 cell surface expression as compared with mutant GABA_B1 was due to the fact that in the case of GABA_B1, only transfected subunits were detected (HA-tagged) but in the case of GABA_B2, transfected as well as endogenously expressed subunits were detected. ***p < 0.001, ^nsp > 0.05; two-tailed unpaired t test