Figure 3. Constitutive activity of TRPV3 G573 mutants expressed in Xenopus oocytes.

Wild type TRPV3 (WT) and the G573C (G/C) or G573S (G/S) mutants were expressed in oocytes by cRNA injection. Currents were recorded by two-electrode voltage clamp. A, time course of current changes at -100 mV for WT in response to the application of 2APB at the room temperature (22 °C) and to temperature change from 22 °C to 40 °C as indicated. The 2APB-evoked response was blocked by ruthenium red (RR, right panel). Insets show I-V curves obtained by voltage ramps under conditions as indicated. B, similar to A but the oocyte expressed G573C. The basal current was partially blocked by RR (10 μM, right panel). Note the similar response to heat in the presence of RR. The current represents unblocked mutant channel activity as well as leak. The increase is due to normal thermodynamic effect as explained in Fig. 5. C, the response of uninjected oocyte to 2APB and heating. D, summary of basal current at -100 mV for all cells. Data points for individual cells are plotted. Mean values are indicated by the thick bars. Controls (Cntl) are uninjected oocytes.