CFTR and cystic fibrosis: Most CFTR is localized in the PM or in recycling endosomes in well-differentiated primary airway epithelial cells and its biosynthetic arrest in CF is associated with remarkable changes in the abundance and intracellular distribution of cholesterol and other lipids (Scholte et al., 2019; Garic et al., 2019; Freedman et al., 1999).