Table 2.
Properties of P2X4-pHluorin receptors expressed in HEK-293 cells
| Construct | Position region | Fluorescence intensity | GFP/β actin ratio | Erev | Rectification index | IATP | Surface fraction | Acidic fraction | Other fluorescence |
| a.u. | mV | −pA | % | % | % | ||||
| WT P2X4 | — | — | — | −0.1 ± 0.8 | 0.79 ± 0.08 | 2,351 ± 315 | — | — | — |
| (n = 14) | (n = 14) | (n = 17) | |||||||
| P2X4-YFP | C tail | 738 ± 62 | 1.0 ± 0.05 | — | — | — | — | — | — |
| (n = 9) | (n = 3) | ||||||||
| P2X4-pHluorin79 | Head | 163 ± 17 | 0.9 ± 0.1 | ND | ND | 24 ± 11 | 42 ± 2 | 41.2 ± 4.1 | 16.8 ± 2.3 |
| (n = 16) | (n = 3) | (n = 8) | (n = 11) | (n = 11) | (n = 11) | ||||
| P2X4-pHluorin82 | Head | 188 ± 28 | 1.8 ± 0.03 | 2.4 ± 1.2 | 0.53 ± 0.03 | 587 ± 155 | 38 ± 3 | 52.2 ± 3.4 | 9.5 ± 1.9 |
| (n = 13) | (n = 3) | (n = 7) | (n = 7) | (n = 8) | (n = 11) | (n = 11) | (n = 11) | ||
| P2X4-pHluorin123 | Beak | 359 ± 25 | 2.0 ± 0.2 | 0.4 ± 0.7 | 0.67 ± 0.09 | 1,853 ± 271 | 38 ± 3 | 50.8 ± 3.1 | 11.2 ± 2.4 |
| (n = 14) | (n = 3) | (n = 9) | (n = 9) | (n = 10) | (n = 14) | (n = 14) | (n = 14) | ||
| P2X4-pHluorin156 | Beak | 343 ± 31 | 1.9 ± 0.2 | −0.03 ± 0.90 | 0.47 ± 0.04 | 472 ± 81 | 28 ± 3 | 51.6 ± 3.2 | 20.4 ± 3.2 |
| (n = 16) | (n = 3) | (n = 7) | (n = 8) | (n = 9) | (n = 12) | (n = 12) | (n = 12) | ||
| P2X4-pHluorin207 | Dorsal fin | 240 ± 9 | 1.5 ± 0.1 | ND | ND | 0.4 ± 0.4 | 13 ± 2 | 33.5 ± 5.1 | 53.1 ± 5.6 |
| (n = 7) | (n = 3) | (n = 3) | (n = 6) | (n = 6) | (n = 6) | ||||
| P2X4-pHluorin222 | Dorsal fin | 120 ± 10 | 0.9 ± 0.1 | ND | ND | 0.9 ± 1.1 | 22 ± 2 | 20.7 ± 5.2 | 57.5 ± 3.5 |
| (n = 6) | (n = 3) | (n = 5) | (n = 5) | (n = 5) | (n = 5) | ||||
| P2X4-pHluorin224 | Dorsal fin | 199 ± 25 | 0.9 ± 0.1 | ND | ND | 5 ± 4 | 14 ± 5 | 36.0 ± 9.6 | 49.7 ± 9.5 |
| (n = 9) | (n = 3) | (n = 5) | (n = 6) | (n = 6) | (n = 6) | ||||
| P2X4-pHluorin304 | Head | 177 ± 19 | 1.9 ± 0.2 | −3.9 ± 1.3 | 0.70 ± 0.09 | 58 ± 15 | 27 ± 3 | 49.4 ± 2.7 | 24.0 ± 3.1 |
| (n = 12) | (n = 3) | (n = 8) | (n = 8) | (n = 8) | (n = 12) | (n = 12) | (n = 12) | ||
| P2X4-pHluorin307 | Head | 185 ± 24 | 1.6 ± 0.3 | −1.7 ± 0.8 | 0.54 ± 0.09 | 88 ± 20 | 36 ± 6 | 52.4 ± 4.1 | 11.6 ± 3.1 |
| (n = 12) | (n = 3) | (n = 8) | (n = 8) | (n = 9) | (n = 10) | (n = 10) | (n = 10) |
Fluorescence intensity documents the average fluorescence intensity of HEK-293 cells expressing the indicated constructs. The rectification index is the ratio of current + and −40 of the ATP-evoked current reversal potential (Erev). The surface, acidic, and nonacidic fractions of receptors were calculated as described in Materials and methods and Results.