Table 3.
Summary of physiological parameters for homomeric wild-type and mutant GluK2 KARs
| GluK2 constructs | Deactivation (ms) | Desensitization (ms) | Degree of desensitization (%) | Recovery (s) | Glutamate EC50(μM) | Peak amplitude (−nA) | Surface localization (%) |
|---|---|---|---|---|---|---|---|
| Wild-type | 2.5 ± 0.1 | 4.9 ± 0.2 | 100 ± 0 | 0.8 (0.7–0.9) | 295 | 8.2 ± 0.6 | 85 ± 3 |
| p.Ala657Thr | 212 ± 82 (p = 0.011) | 18 ± 1 (p < 0.001) | 91 ± 1 (p < 0.0001) | 0.5 (0.4–0.6) | 47 (11–179) | 1.4 ± 0.2 (p < 0.0001) | 51 ± 5 (p < 0.0001) |
| p.Thr660Lys | 260 ± 14 (p = 0.002) | 8.9 ± 0.2 (NS) | 57 ± 1 (p < 0.0001) | 0.5 (0.2–0.9) | 19 (15–26) | 0.65 ± 0.08 (p < 0.0001) | 16 ± 5 (p < 0.0001) |
| p.Thr660Arg | 183 ± 27 (p = 0.023) | 9.6 ± 1.6 (p = 0.009) | 75 ± 1 (p < 0.0001) | 0.9 (0.4–1.4) | 52 (38–73) | 1.9 ± 0.2 (p < 0.0001) | 12 ± 6 (p < 0.0001) |
| p.Ile668Thr | 1.5 ± 0.1 (NS) | 1.7 ± 0.1 (NS) | 98 ± 0.5 (NS) | 2.4 (2.1–2.8) | 3700 (2,300–10,800) | 0.16 ± 0.02 (p < 0.0001) | 91 ± 1 (NS) |
τ values from fits to the data are given for deactivation, desensitization, and recovery from desensitization as described in the text. The data are expressed as mean ± SEM. Statistical information is given where significantly different from wild-type GluK2 receptors, except for 95% confidence intervals shown for recovery from desensitization and for the EC50 values. NS, not significant.