MONNA and Ani9 inhibit TMEM16A-conducted Cl− currents. (A) Representative bright-field and fluorescence images of axolotl oocytes expressing Ruby-tagged xBEST2a and enhanced GFP–tagged MemE (reporter of plasma membrane). Boxes denote portions included in fluorescence images. Bars, 750 µm. Overlay is of GFP and Ruby images. (B) Schematic of experimental design: UV photolysis to uncage IP3 while conducting TEVC. (C–F) Current recordings from oocytes of axolotls (C, D, and F) or X. laevis (E), after injection with a photolabile caged-IP3 analogue, with clamping at −80 mV. Axolotl oocytes expressed no transgene (C), xTMEM16A (D), or xBEST2A (F). Wild-type X. laevis oocytes expressing endogenous channels (E). Typical current traces before and after uncaging, during (colored) control treatment, and (black) in the presence of 10 µM MONNA. Red bar denotes the 250-ms duration of UV exposure. (G) Tukey box plot distributions of the averaged proportion of current remaining after application of the indicated inhibitors, in axolotl oocytes expressing xTMEM16A (n = 6–14) or xBEST2A (n = 6–8), and in X. laevis oocytes expressing endogenous channels (n = 5–16). The central line represents the median value and the box denotes the data spread from 25–75%, and the whiskers reflect 10–90%.
