CFTR and cystic fibrosis: As positive control, being RNF5 a known CFTR channel regulator, we verified also RNF5 expression in primary human bronchial epithelial (HBE) cells from a non-CF patient (donor ID: HBE121), primary human bronchial epithelial cells from a CF subject (F508del/F508del) (donor ID: HBE55), in immortalized human bronchial epithelial cells overexpressing the F508del-CFTR mutant (CFBE41o-) and for comparison human fibroblasts (Figure 2a, Supplementary Figures S4 and S5).