Table 1. Kinetic properties of wild type and chimeric TARPs and GluA2 linker mutants.
kdes is rate of desensitization, Iss the steady state current expressed as percentage of the peak current and "Superact." the extent of superactivation expressed as the slow increase in steady state current during prolonged exposure to glutamate (see Materials and methods for details). The number of patches recorded for each condition is shown in brackets. Values are shown as mean ± s.e.m. p values (from Student’s t test) are calculated as follows: § against the parent TARP; ∆ against GluA2 WT; # against GluA2 WT + TARP. Currents recorded in the presence of TARPs were held at +50 mV in the presence of 50 µM spermine in the pipette solution. Recordings in the absence of TARPs were done at –60 mV without intracellular polyamines. Source data for Table 1 is found in Table 1–source data 1.
| Construct | kdes (s-1) | P | Iss (%) | P | Superact. (%) | P |
|---|---|---|---|---|---|---|
| A2 wt | 120 ± 15 (9) | 5 ± 1 | − | − | ||
| γ2 | 60 ± 5 (24) | 25 ± 2 | 7 ± 2 (10) | |||
| γ8 | 40 ± 5 (9) | 25 ± 5 | 30 ± 6 (4) | |||
| γ2 β4 TM2 § | 40 ± 5 (7) | 0.004 | 50 ± 5 | 1 × 10–5 | 17 ± 4 (5) | 0.009 |
| L1 γ8 in γ2 § | 35 ± 5 (30) | 5 × 10–6 | 50 ± 5 | 7 × 10–6 | 27 ± 6 (10) | 0.003 |
| L1 γ2 in γ8 § | 45 ± 1 (28) | 0.34 | 25 ± 3 | 0.86 | 16 ± 1 (16) | 0.001 |
| γ2 ΔL1 § | 60 ± 5 (11) | 0.90 | 15 ± 2 | 0.008 | 6 ± 2 (6) | 0.52 |
| γ8 ΔL1 § | 60 ± 5 (15) | 0.002 | 15 ± 3 | 0.03 | 16 ± 3 (6) | 0.02 |
| γ2 L2_GS § | 65 ± 5 (15) | 0.49 | 5 ± 1 | 1 × 10–6 | 1.3 ± 0.6 (8) | 0.003 |
| γ8 L2_GS § | 25 ± 5 (6) | 0.002 | 40 ± 4 | 0.07 | 12 ± 2 (4) | 0.01 |
| L1 γ8 in γ2 L2_GS § | 10 ± 0.5 (7) | 6 × 10–10 | 45 ± 3 | 6 × 10–5 | 4 ± 2 (6) | 0.19 |
| L1 γ2 in γ8 L2_GS § | 85 ± 5 (6) | 1 × 10–5 | 5 ± 1 | 0.001 | 1 ± 0.7 (6) | 9 × 10–5 |
| γ2 ΔL1 L2_GS § | 80 ± 20 (5) | 0.03 | 2 ± 1 | 4 × 10–4 | 0 (4) | 0.011 |
| γ8 ΔL1 L2_GS § | 60 ± 10 (5) | 0.02 | 10 ± 5 | 0.02 | 3 ± 1 (4) | 0.02 |
| A2 K509A ∆ | 100 ± 5 (5) | 0.34 | 3 ± 0.5 | 0.71 | − | − |
| A2 508GAG510 ∆ | 145 ± 35 (3) | 0.42 | 1 ± 0.5 | 0.27 | − | − |
| A2 781GSG783 ∆ | 110 ± 15 (3) | 0.76 | 2 ± 1 | 0.46 | − | − |
| A2 GAG/GSG ∆ | 150 ± 20 (5) | 0.20 | 2 ± 1 | 0.44 | − | − |
| A2 K509A + γ2 # | 30 ± 10 (5) | 3 × 10–4 | 45 ± 3 | 2 × 10–4 | 5 ± 5 (4) | 0.59 |
| A2 508GAG510 + γ2 # | 70 ± 5 (4) | 0.39 | 10 ± 5 | 0.07 | 0 (3) | 0.03 |
| A2 781GSG783 + γ2 # | 60 ± 5 (9) | 0.60 | 10 ± 1 | 0.001 | 2 ± 0.5 (8) | 0.005 |
| A2 GAG/GSG + γ2 # | 80 ± 5 (8) | 0.01 | 5 ± 1 | 9 × 10–5 | 0 (4) | 0.01 |
| A2 GAG/GSG + L1 γ8 in γ2 # | 12 ± 0.5 (5) | 4 × 10–8 | 30 ± 5 | 0.21 | 2 ± 2 (4) | 0.065 |
| A2 GAG/GSG + γ8 # | 45 ± 2 (5) | 0.30 | 12 ± 3 | 0.03 | 25 ± 5 (5) | 0.37 |
| A2 GAG/GSG + L1 γ2 in γ8 # | 72 ± 5 (5) | 8 × 10–5 | 4 ± 1 | 0.001 | 1 ± 1 (4) | 0.001 |
| A2 GAG/GSG + γ2 L2_GS # | 90 ± 10 (9) | 3 × 10–4 | 2 ± 1 | 5 × 10–6 | 0 (4) | 0.01 |