The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a chloride transporter that when mutated, causes cystic fibrosis. The structure of CFTR has not been determined experimentally; the structures shown on this page are based on a model built at [1]/, using the multidrug resistance protein, pgp-1 (pdb code 4f4c, as a model. The protein has twelve membrane spanning helices and two nucleotide binding domains. Chloride transport is regulated by both ATP and cAMP.
Like most diseases, there is not a single unique mutation that leads to cystic fibrosis; rather, a wide variety of sequence alterations leads to varying disease severity.[1] The most severe symptoms are seen in patients who do not express CFTR on the epithelial membranes, due to nonsense or frame shift mutations or splicing errors. There are also a number of mutations associated with errors in processing, including the most common mutation, F508del. Less severe symptoms are seen in patients with point mutations of ; many of these changes are found in the loop regions. Changes in conduction are observed in patients with mutations of located in the membrane spanning domain that are associated with ion selectivity.
