CFTR and cystic fibrosis: For example, Hsc70 has been shown to promote folding of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel and also to be involved in the ERAD of the folding-deficient Phe508-deleted (ΔF508) CFTR, the most common cystic fibrosis-causing mutation worldwide12.