Figure 4.

Figure 4.

The VSD-targeted activator ICA-069673 does not weaken ML252 inhibition. (A and B) Exemplar records of WT Kv7.2 or Kv7.2[W236F] homomers expressed in Xenopus oocytes, and treated with ICA-069673 (ICA) and ML252 as indicated. Oocytes were held at –80 mV and pulsed between –140 and +40 mV in 10 mV steps. (C) ML252 concentration responses were assessed in WT Kv7.2 and Kv7.2[W236F] channels, in the presence of 30 μm ICA-069673. Currents were recorded at +20 mV and normalized to peak current at +20 mV in ICA-069673 alone (n = 4–7). (D) Normalized WT Kv7.2 and Kv7.2[W236F] current magnitudes in HEK293 cells upon application or washout with indicated combinations of 30 μm ICA-069673 and 30 μm ML252, normalized to currents measured in the absence of drugs and collected as depicted in panels E to H (For WT Kv7.2: ICA-069673 application, n = 9, washout, n = 5; ICA-069673 + ML252 application, n = 12, washout, n = 6) (For Kv7.2[W236F]: ICA-069673 application, n = 12, washout, n = 8; ICA-069673 + ML252 application, n = 12, washout, n = 9 washout of ICA-069673 and ML252). (E to H) Exemplar patch-clamp recordings of HEK293 cells expressing WT Kv7.2 (E and F) or Kv7.2[W236F] (G and H). Cells were held at +20 mV throughout the recording and combinations of ML252 and ICA-069673 were applied where indicated, dashed lines indicate zero current.