Fig. 2: Functional characterization of GluA2 complexes with γ5 and CNIH2.
a, Representative whole-cell currents recorded at −60 mV membrane potential from HEK293 cell coexpressing GluA2–γ5 and CNIH2 in response to 2 ms (red) or 500 ms (blue) application of 3 mM Glu alone or application of Glu in the continuous presence of 30 µM CTZ (green). The inset shows close-up superposition of currents in response to 2 ms and 0.5 s applications of Glu alone. b–d, Time constants of deactivation (b, τDeact) and desensitization (c, τDes) and the fraction of nondesensitized channels (d, ISS/IMax) measured for currents recorded from HEK293 cells transfected with GluA2 (yellow), GluA2–γ5 (green), GluA2 and CNIH2 (blue) and GluA2–γ5 and CNIH2 (purple). Asterisks indicate statistically significant differences (two-sided two-sample t-test; the significance is assumed if P < 0.05). For τDeact (b), the number of independent experiments, n = 9 for GluA2, n = 8 for GluA2–γ5, n = 11 for GluA2 and CNIH2, and n = 9 for GluA2–γ5 and CNIH2. Probabilities for the two-sided two-sample t-test, P = 0.222 for GluA2 versus GluA2–γ5, P = 2.70 × 10−4 for GluA2 versus GluA2 and CNIH2, P = 1.15 × 10−4 for GluA2 versus GluA2–γ5 and CNIH2, P = 7.79 × 10−4 for GluA2–γ5 versus GluA2 and CNIH2, P = 4.83 × 10−4 for GluA2–γ5 versus GluA2–γ5 and CNIH2, and P = 0.00445 for GluA2 and CNIH2 versus GluA2–γ5 and CNIH2. For τDes (c), the number of independent experiments, n = 35 for GluA2, n = 10 for GluA2–γ5, n = 11 for GluA2 and CNIH2, and n = 14 for GluA2–γ5 and CNIH2. Probabilities for the two-sided two-sample t-test, P = 0.673 for GluA2 versus GluA2–γ5, P = 3.28 × 10−10 for GluA2 versus GluA2 and CNIH2, P = 1.91 × 10−7 for GluA2 versus GluA2–γ5 and CNIH2, P = 4.91 × 10−4 for GluA2–γ5 versus GluA2 and CNIH2, P = 0.0037 for GluA2–γ5 versus GluA2–γ5 and CNIH2, and P = 0.0058 for GluA2 and CNIH2 versus GluA2–γ5 and CNIH2. For ISS/IMax (d), the number of independent experiments, n = 26 for GluA2, n = 9 for GluA2–γ5, n = 11 for GluA2 and CNIH2, and n = 11 for GluA2–γ5 and CNIH2. Probabilities for the two-sided two-sample t-test, P = 0.0265 for GluA2 versus GluA2–γ5, P = 6.76 × 10−8 for GluA2 versus GluA2 and CNIH2, P = 0.385 for GluA2 versus GluA2–γ5 and CNIH2, P = 1.72 × 10−5 for GluA2–γ5 versus GluA2 and CNIH2, P = 0.00395 for GluA2–γ5 versus GluA2–γ5 and CNIH2, and P = 2.55 × 10−4 for GluA2 and CNIH2 versus GluA2–γ5 and CNIH2. Data are mean ± s.e.m. e, Mean recovery from desensitization for GluA2–γ5–CNIH2 activated by Glu measured using the two-pulse protocol illustrated in the inset. The red curve through the points is a fit with the Hodgkin–Huxley equation. The number of independent experiments, n = 8. Error bars represent s.e.m. f, Time constant of recovery from desensitization (τRecDes). Asterisks indicate statistically significant differences (two-sided two-sample t-test; the significance is assumed if P < 0.05). The number of independent experiments, n = 14 for GluA2, n = 6 for GluA2–γ5, n = 9 for GluA2 and CNIH2, and n = 8 for GluA2–γ5 and CNIH2. Probabilities for the two-sided two-sample t-test, P = 5.53 × 10−4 for GluA2 versus GluA2–γ5, P = 0.00707 for GluA2 versus GluA2 and CNIH2, P = 4.38 × 10−8 for GluA2 versus GluA2–γ5 and CNIH2, P = 0.0418 for GluA2–γ5 versus GluA2 and CNIH2, P = 0.811 for GluA2–γ5 versus GluA2–γ5 and CNIH2, and P = 1.72 × 10−4 for GluA2 and CNIH2 versus GluA2–γ5 and CNIH2. Data are mean ± s.e.m.
