Table 1.
Effect of external acidification on KCNQ1 and Iks parameters in Chinese hamster ovary (CHO) cells and Xenopus oocytes
| CHO cells (n = 9–42) | Xenopus oocytes (n = 5–12) | ||||||
|---|---|---|---|---|---|---|---|
| Current density at + 60mV (pA pF−1) | V50 (mV) | Slope (mV) | Current amplitude at +30mV (μA) | V50 (mV) | Slope (mV) | ||
| WT KCNQ1 | pH 7.4 | 140.2 ± 13.7 | −16.0 ± 1.5 | −8.7 ± 0.4 | 1.28 ± 0.11 | −24.8 ± 2.4 | −17.9 ± 1.3 |
| pH 5.5 | 68.3 ± 7.5 | 9.4 ± 3.9 | −10.6 ± 0.6 | 0.9 ± 0.08 | 0.8 ± 1.6 | −25.2 ± 1.45 | |
| L273F KCNQ1 | pH 7.4 | 64.3 ± 14.7 | −20.9 ± 1.7 | −18.2 ± 0.9 | ND | ND | ND |
| pH 5.5 | 50.5 ± 10.8 | −11.9 ± 3.1 | −17.5 ± 0.9 | ND | ND | ND | |
| WTKCNQ1+WTKCNE1 | pH 7.4 | 463.7 ± 49.3 | 22.4 ± 2.8 | −17.4 ± 1.2 | 2.97 ± 0.39 | −1.2 ± 0.9 | −14.2 ± 0.7 |
| pH 5.5 | 340.0 ± 54.2 | 21.4 ± 2.2 | −14.9 ± 1.5 | 2.80 ± 0.42 | −4.9 ± 1.6 | −16.5 ± 0.9 | |
| WTKCNQ1 +Δ 39-43 KCNE1 | pH 7.4 | 301.4 ± 66.2 | +34.1 ± 5.7 | −18.9 ± 1.3 | 0.81 ± 0.06 | −24.9 ± 7.7 | −11.9 ± 0.5 |
| pH 5.5 | 259.0 ± 53.6 | +29.9 ± 3.1 | −15.6 ± 0.5 | ND | ND | ND | |
| WTKCNQ1 + Δ 11–38 KCNE1 | pH 7.4 | ND | ND | ND | 1.92 ± 0.25 | −10.8 ± 1.8 | −13.6 ± 1.4 |
| pH 5.5 | ND | ND | ND | 1.20 ± 0.06 | −18.4 ± 2.5 | −15.1 ± 1.9 | |
| V319C KCNQ1 + WTKCNE1 | pH 7.4 | 226.5 ± 30.3 | 28.6 ± 1.6 | −13.2 ± 0.4 | 0.62 ± 0.06 | ND | ND |
| pH 5.5 | 274.5 ± 35.4 | 28.8 ± 4.1 | −15.1 ± 0.8 | ND | ND | ND | |
WT, Wild type; ND, not done; V50, voltage at which the current is half-activated