| Channel . | pH50a . | na . | pH50SSD . | nSSD . | Is/Ip . | τD (s) . |
|---|---|---|---|---|---|---|
| hASIC1a | ||||||
| WT | 6.60 ± 0.18 | 4.5 | 7.1 ± 0.09 | 7.5 | 0.0 | 1.65 ± 0.15 |
| R64G | 6.23 ± 0.08 | 3.2 | 7.05 ± 0.07 | 4.2 | 0.0 | 1.0 ± 0.2 |
| R64E | 6.50 ± 0.05 | 4.8 | 7.1 ± 0.08 | 7.3 | 0.0 | 1.06 ± 0.05 |
| R64K | 6.60 ± 0.10 | 4.7 | 6.98 ± 0.01 | 7.8 | 0.17 ± 0.004 | 2.05 ± 0.2 |
| R64C | 6.61 ± 0.09 | 4.2 | 7.1 ± 0.05 | 7.3 | 0.0 | 2.5 ± 0.02 |
| R64A | 6.63 ± 0.02 | 3.6 | 7.14 ± 0.03 | 7.1 | 0.0 | 1.06 ± 0.1 |
| R64M | 6.84 ± 0.1 | 3.5 | 7.01 ± 0.07 | 8.0 | 0.0 | 6.8 ± 0.1 |
| R64L | 6.82 ± 0.06 | 6.5 | 7.0 ± 0.012 | 8.5 | 0.07 ± 0.002 | 6.6 ± 0.1 |
| R64Y | 7.06 ± 0.1 | 8.0 | ND | ND | 0.21 ± 0.02 | 6.5 ± 0.2 |
| R64F | 7.1 ± 0.1 | 7.4 | ND | ND | 0.77 ± 0.08 | ND |
| R64W | 7.09 ± 0.4 | 7.0 | ND | ND | 0.33 ± 0.09 | 7.8 ± 0.1 |
| L58V | 6.59 ± 0.1 | 4.8 | 7.1 ± 0.01 | 7.0 | 0.0 | 1.6 ± 0.15 |
| V60Q | 6.55 ± 0.12 | 4.5 | 7.1 ± 0.02 | 6.9 | 0.0 | 1.63 ± 0.02 |
| C61S | 6.5 ± 0.06 | 4.2 | 7.14 ± 0.05 | 7.2 | 0.0 | 1.59 ± 0.1 |
| T62L | 6.45 ± 0.08 | 4.9 | 7.17 ± 0.08 | 7.0 | 0.0 | 1.1 ± 0.09 |
| E63D | 6.58 ± 0.09 | 4.3 | 7.11 ± 0.07 | 6.8 | 0.0 | 1.6 ± 0.03 |
| lASIC | ||||||
| WT | 7.21 ± 0.1 | 9.4 | ND | ND | 1.0 | ND |
| W66R | 6.8 ± 0.2 | 2.9 | 7.2 ± 0.005 | 11 | 0.0 | 1.4 ± 0.04 |
| W66C | 6.78 ± 0.1 | 2.6 | 7.1 ± 0.002 | 9.0 | 0.08 ± 0.01 | 1.85 ± 0.1 |
| W66F | 7.3 ± 0.2 | 9.4 | ND | ND | 1.0 | ND |
| mASIC2 | ||||||
| WT | 4.0 ± 0.2 | 2.0 | 0.22 ± 0.05 | 2.5 ± 0.05 | ||
| R63F | 6.0 ± 0.1 | 4.0 | 0.68 ± 0.08 | |||
| R63W | 6.0 ± 0.3 | 4.0 | 0.69 ± 0.06 | |||
| mASIC3 | ||||||
| WT | 6.0 ± 0.1 | 1.0 | 0.0 | 0.27 ± 0.07 | ||
| R64F | 7.0 ± 0.3 | 7.0 | 0.91 ± 0.06 |
| Channel . | pH50a . | na . | pH50SSD . | nSSD . | Is/Ip . | τD (s) . |
|---|---|---|---|---|---|---|
| hASIC1a | ||||||
| WT | 6.60 ± 0.18 | 4.5 | 7.1 ± 0.09 | 7.5 | 0.0 | 1.65 ± 0.15 |
| R64G | 6.23 ± 0.08 | 3.2 | 7.05 ± 0.07 | 4.2 | 0.0 | 1.0 ± 0.2 |
| R64E | 6.50 ± 0.05 | 4.8 | 7.1 ± 0.08 | 7.3 | 0.0 | 1.06 ± 0.05 |
| R64K | 6.60 ± 0.10 | 4.7 | 6.98 ± 0.01 | 7.8 | 0.17 ± 0.004 | 2.05 ± 0.2 |
| R64C | 6.61 ± 0.09 | 4.2 | 7.1 ± 0.05 | 7.3 | 0.0 | 2.5 ± 0.02 |
| R64A | 6.63 ± 0.02 | 3.6 | 7.14 ± 0.03 | 7.1 | 0.0 | 1.06 ± 0.1 |
| R64M | 6.84 ± 0.1 | 3.5 | 7.01 ± 0.07 | 8.0 | 0.0 | 6.8 ± 0.1 |
| R64L | 6.82 ± 0.06 | 6.5 | 7.0 ± 0.012 | 8.5 | 0.07 ± 0.002 | 6.6 ± 0.1 |
| R64Y | 7.06 ± 0.1 | 8.0 | ND | ND | 0.21 ± 0.02 | 6.5 ± 0.2 |
| R64F | 7.1 ± 0.1 | 7.4 | ND | ND | 0.77 ± 0.08 | ND |
| R64W | 7.09 ± 0.4 | 7.0 | ND | ND | 0.33 ± 0.09 | 7.8 ± 0.1 |
| L58V | 6.59 ± 0.1 | 4.8 | 7.1 ± 0.01 | 7.0 | 0.0 | 1.6 ± 0.15 |
| V60Q | 6.55 ± 0.12 | 4.5 | 7.1 ± 0.02 | 6.9 | 0.0 | 1.63 ± 0.02 |
| C61S | 6.5 ± 0.06 | 4.2 | 7.14 ± 0.05 | 7.2 | 0.0 | 1.59 ± 0.1 |
| T62L | 6.45 ± 0.08 | 4.9 | 7.17 ± 0.08 | 7.0 | 0.0 | 1.1 ± 0.09 |
| E63D | 6.58 ± 0.09 | 4.3 | 7.11 ± 0.07 | 6.8 | 0.0 | 1.6 ± 0.03 |
| lASIC | ||||||
| WT | 7.21 ± 0.1 | 9.4 | ND | ND | 1.0 | ND |
| W66R | 6.8 ± 0.2 | 2.9 | 7.2 ± 0.005 | 11 | 0.0 | 1.4 ± 0.04 |
| W66C | 6.78 ± 0.1 | 2.6 | 7.1 ± 0.002 | 9.0 | 0.08 ± 0.01 | 1.85 ± 0.1 |
| W66F | 7.3 ± 0.2 | 9.4 | ND | ND | 1.0 | ND |
| mASIC2 | ||||||
| WT | 4.0 ± 0.2 | 2.0 | 0.22 ± 0.05 | 2.5 ± 0.05 | ||
| R63F | 6.0 ± 0.1 | 4.0 | 0.68 ± 0.08 | |||
| R63W | 6.0 ± 0.3 | 4.0 | 0.69 ± 0.06 | |||
| mASIC3 | ||||||
| WT | 6.0 ± 0.1 | 1.0 | 0.0 | 0.27 ± 0.07 | ||
| R64F | 7.0 ± 0.3 | 7.0 | 0.91 ± 0.06 |
pH50a, pH50 of activation; na, Hill coefficient of activation; pH50SSD, pH50 of steady stead desensitization; nSSD, n coefficient of SSD; Is/Ip, ratio of sustained current/peak current both measured at pH50a; tD, 1/rate of desensitization from open state measured at pH50a in seconds; N.D., not determined owing to absent or very weak desensitization. For channels exhibiting a fraction of sustained currents, tD corresponds to the desensitizing component of the current fit to a single exponential. Each data point represents the mean of at least four measurements from independent cells ± SD.