Extended Data Fig. 3. NKCC1 is required for ionocyte basolateral uptake of anions.
Representative images and traces of basolateral I– uptake in YFP halide sensor expression ionocytes of ALI cultures. a, Basolateral Cl– to I– buffer exchange in the presence of forskolin/IBMX (F&I) does not lead to ionocyte YFP quenching in homeostatic apically-hydrated cultures at baseline or following apical Cl– buffer addition (18 μl) with F&I. Mean ± s.e.m.; n = 17 ionocytes. b, In apically-dehydrated cultures, basolateral Cl– to I– + F&I buffer exchange leads to basolateral I– uptake, but only after apical Cl– buffer addition with F&I. Mean ± s.e.m.; n = 9 ionocytes. c, Basolateral I– uptake by ionocyte, as shown in (b), requires the NKCC1 channel and is blocked by bumetanide. Mean ± s.e.m.; n = 17 ionocytes. d, Basolateral I– uptake by ionocyte, as shown in (b), requires apical Cl– and is not observed after apical Na-gluconate (Na-Gluc) buffer addition with I&F. Mean ± s.e.m.; n = 7 ionocytes. e,f. In vivo tracheal mucociliary clearance (MCC) measured by 68Ga-MAA PET-CT in FOXI1-CreERT2::CFTRL/L ferrets prior to and following CFTR deletion with tamoxifen (n = 2 animals, range in values is shown on both graphs).