Trafficking of GFP-tagged ΔF508-CFTR to the plasma membrane in a polarized epithelial cell line

The ΔF508 mutation reduces the amount of cystic fibrosis transmembrane conductance regulator (CFTR) expressed in the plasma membrane of epithelial cells. However, a reduced temperature, butyrate compounds, and “chemical chaperones” allow ΔF508-CFTR to traffic to the plasma membrane and increase Cl− permeability in heterologous and nonpolarized cells. Because trafficking is affected by the polarized state of epithelial cells and is cell-type dependent, our goal was to determine whether these maneuvers induce ΔF508-CFTR trafficking to the apical plasma membrane in polarized epithelial cells. To this end, we generated and characterized a line of polarized Madin-Darby canine kidney (MDCK) cells stably expressing ΔF508-CFTR tagged with green fluorescent protein (GFP). A reduced temperature, glycerol, butyrate, or DMSO had no effect on 8-(4-chlorophenylthio)-cAMP (CPT-cAMP)-stimulated transepithelial Cl− secretion across polarized monolayers. However, when the basolateral membrane was permeabilized, butyrate, b...