CFTR and cystic fibrosis: Some of these challenges have been addressed by introducing stabilizing mutations and deleting inherently disordered regions, which was critical for the success of recent cryo-EM studies of the human Cystic Fibrosis Transmembrane Regulator (CFTR), an anion channel important for maintaining the salt balance in stratified epitheliums such as the lung and mutated in the misfolding disease Cystic Fibrosis.