Fig. 4
From: Homomeric GluA2(R) AMPA receptors can conduct when desensitized
Large steady-state GluA2(R)/γ-2 currents are observed even in conditions favoring desensitization. a Representative GluA2(R)/γ-2 current (–60 mV) evoked by 10 mM glutamate (gray bar) in the presence of 50 µM cyclothiazide (green bar). Note the minimal current decay when desensitization is inhibited (for pooled data ISS/Ipeak = 93.4 ± 1.6%, n = 6) (mean ± s.e.m. from n patches). b Representative glutamate-evoked currents from Q- and R-forms of GluA2 S754D/γ-2. Both forms exhibit very fast desensitization, but the R-form has an appreciable steady-state current. c Pooled data showing desensitization kinetics (τw,des) for wild-type (wt; n = 6 and 5) and mutant (S754D; n = 5 and 5) forms of GluA2(Q)/γ-2 and GluA2(R)/γ-2. Box-and-whisker plots as in Fig. 1c. Two-way ANOVA indicated an effect of Q/R editing (F1, 17 = 10.56, P = 0.0047), an effect of the mutation (F1, 17 = 43.19, P < 0.0001) but no interaction (F1, 17 = 2.63, P = 0.12). The mean difference between S754D and wild type was –8.1 ms (95% confidence interval, –10.9 to –6.0) for Q and –14.1 ms (95% confidence interval, –20.0 to –9.3) for R. d Pooled data (as in c) for recovery kinetics (τw,recov). Two-way ANOVA indicated no effect of Q/R editing (F1, 17 = 0.13, P = 0.72), an effect of the mutation (F1, 17 = 31.67, P < 0.0001) but no interaction (F1, 17 = 1.65, P = 0.22). The mean difference between S754D and wild type was 24.1 ms (95% confidence interval, 15.3 to 33.2) for Q and 38.7 ms (95% confidence interval, 23.7 to 53.9) for R. e Pooled data (as in c) for the fractional steady-state current (ISS). Two-way ANOVA indicated an effect of Q/R editing (F1, 17 = 65.37, P < 0.0001), an effect of the mutation (F1, 17 = 28.37, P < 0.0001), and an interaction (F1, 17 = 14.93, P = 0.0012). The mean difference in ISS (% of peak) between S754D and wild type was –7.7 (95% confidence interval, –11.2 to –5.2) for Q and –37.9 (95% confidence interval, –49.2 to –25.8) for R. Indicated P values are from Welch t-tests. Source data are provided as a Source Data file
