cystic fibrosis transmembrane conductance regulator

Overview

The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter-class ion channel encoded by the CFTR gene (Wikidata: Q420470) on human chromosome 7q31.2. The protein functions primarily as a regulated chloride and bicarbonate anion channel expressed at the apical surface of epithelial cells lining the airways, intestine, pancreatic ducts, sweat glands, and reproductive tract. CFTR channel gating is controlled by phosphorylation of its regulatory (R) domain and by ATP binding and hydrolysis at its two nucleotide-binding domains. When CFTR function is lost or severely diminished — due to any of more than 2,000 identified pathogenic variants in the CFTR gene — chloride transport across epithelial membranes is disrupted, leading to the accumulation of abnormally thick, dehydrated mucus and the multisystem disease known as cystic fibrosis (CF).

CF is one of the most common life-limiting autosomal recessive disorders in populations of Northern European descent, affecting the respiratory system most critically through cycles of mucus obstruction, bacterial infection, and progressive inflammation, while also causing pancreatic exocrine insufficiency, intestinal dysmotility, hepatobiliary disease, and male infertility. The severity and organ distribution of disease depend heavily on the specific class of CFTR mutation carried by an individual. Class I mutations introduce premature stop codons (nonsense mutations) that prevent full-length protein synthesis; Class II mutations (most notably F508del, the most prevalent CF allele) cause misfolding and premature proteasomal degradation; Class III mutations impair channel gating; and Classes IV–VI affect conductance, expression levels, or protein stability. This mutation-class framework has become central to the development and clinical stratification of CFTR-targeting pharmacotherapies, broadly termed CFTR modulators.

Focus of Latest Publications

Recent publications on cystic fibrosis transmembrane conductance regulator (CFTR) have focused on both improving CFTR function and measuring its effects more precisely in disease models and patients. Several studies examined CFTR modulators, including elexacaftor/tezacaftor/ivacaftor (ETI) and lumacaftor/ivacaftor, with one proteomics analysis showing that modulator therapy alters plasma and serum protein signatures related to inflammation and metabolism, and that ETI produces broader and more consistent shifts toward profiles seen in healthy individuals than lumacaftor/ivacaftor. A separate real-world pediatric study evaluated genotype-dependent biochemical responses to ETI using sweat chloride concentration as a biomarker of CFTR function, reflecting ongoing efforts to define how different CFTR variants respond to treatment over time.

Other recent work has emphasized functional testing and drug design for CFTR. A flexible electrochemical sensor modified with silver nanoparticles was developed to quantify chloride ions in epithelial CF models, enabling discrimination of chloride levels across CFTR genotypes and detection of ETI-induced, genotype-dependent increases in chloride secretion. The study reported strong correlation between measured chloride levels and normalized secretion rates, supporting portable electrochemical sensing as a rapid approach for theratyping. In parallel, medicinal chemistry work on the CFTR potentiator ABBV-974 showed that modifying the lipophilic substituent at the protein-membrane interface increased functional residence time and delayed current decay after washout, suggesting that membrane-facing ligand design can improve long-acting potentiators.

Gene correction strategies were also a major theme. One study used adenine base editing with SpRY-ABE9 to correct the CFTR 1717-1G>A splicing mutation in airway epithelial cells and intestinal organoids derived from people with cystic fibrosis, restoring CFTR channel activity in short-circuit current and forskolin-induced swelling assays. Another study engineered precision A3G base editors with relaxed PAM constraints and improved single-cytosine specificity, then validated them by installing and correcting cystic fibrosis-causing mutations; in bronchial epithelial cells, precise editing altered CFTR mRNA levels, protein expression, and channel function. Together, these studies highlight growing interest in permanent genetic correction of CFTR defects alongside pharmacologic rescue.

Recent publications also explored conditions that influence rescue of CFTR variants not readily corrected by standard modulators. In airway epithelia carrying nonsense mutations such as G542X and W1282X, a triple combination of ELX-02, VX-809, and CC-90009 produced modest CFTR recovery under baseline conditions but markedly greater rescue when cells were exposed to inflammatory stimuli, including Interleukin 4 or IL17A/Tumour necrosis factor alpha. This enhanced effect was accompanied by increased full-length CFTR protein and CFTR mRNA, suggesting that inflammation may alter translational readthrough and/or nonsense-mediated decay. In addition, a retrospective study in children with cystic fibrosis reported high coverage for mandatory vaccines and pneumococcal and Hib immunization, but lower-than-target coverage for influenza and COVID-19 vaccination, underscoring the continuing importance of infection prevention in the era of improved CFTR-directed care.

Key Publications

NEWJun Suboptimal vaccine coverage for preventable respiratory infections in children with cystic fibrosis in the Cystic Fibrosis Regional Reference Centre of Tuscany: Need for improving preventive strategies. (Human vaccines & immunotherapeutics, 2026, PMID 42373575): "Advances in standards of care and the recent introduction of Cystic Fibrosis transmembrane conductance regulator (CFTR) modulators have significantly improved the prognosis for individuals with cystic fibrosis (CF)."
Jun Toward Precision Electrochemical Sensing of CFTR Function in Cystic Fibrosis Models. (Analytical chemistry, 2026, PMID 42240701): "The assessment of cystic fibrosis transmembrane conductance regulator (CFTR) activity is essential to both diagnose and evaluate the efficacy of treatments in cystic fibrosis (CF)."
Jun Comparison of Long Term Effects of Treatment of Different CFTR Modulators in People With Cystic Fibrosis. (Pediatric pulmonology, 2026, PMID 42206906): "Cystic fibrosis transmembrane conductance regulator modulators (CFTRm) represent a breakthrough in the treatment of people with cystic fibrosis (PwCF), offering improvements in health outcomes and quality of life (QoL) previously unattainable."
Jun Genotype-dependent biochemical response to elexacaftor/tezacaftor/ivacaftor in children with cystic fibrosis: A 24-month real-world study. (Respiratory medicine, 2026, PMID 42067070): "This study compared the real-world response to ETI using sweat chloride concentration (SCC) as a key biomarker of CFTR function."
May Targeting the Protein-Membrane Interface Enables Design of Long-Acting CFTR Potentiators. (ACS chemical biology, 2026, PMID 42046515): "CFTR potentiators, a clinically validated drug class for cystic fibrosis, offer a compelling model for exploring membrane-targeted design principles, as their efficacy depends on sustained intramembrane binding to prolong channel opening and chloride conductance."
Apr Functional correction of the untreatable CFTR 1717-1G>A mutation through mRNA- and sgRNA-optimized base editing. (Science translational medicine, 2026, PMID 42018671): "This mutation disrupts a canonical 3' AG splice acceptor site in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, leading to severe RNA missplicing, which prevents the correct synthesis of the encoded protein."
May Systemic effects of cystic fibrosis transmembrane conductance regulator modulators on the plasma and serum proteome. (Cell systems, 2026, PMID 41928517): "Cystic fibrosis (CF) is caused by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel in epithelial organs leading to a complex multi-organ disease."
Apr Precision A3G base editors for disease modeling and correction. (Molecular therapy : the journal of the American Society of Gene Therapy, 2026, PMID 41536070): "When applied to 16HBE14o-human bronchial epithelial cells, precise editing modulated cystic fibrosis transmembrane conductance regulator mRNA levels, protein expression, and channel function."
May Rescue of the CFTR chloride channel with nonsense mutations is markedly improved under inflammatory conditions. (The European respiratory journal, 2026, PMID 41381228): "Loss of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel function is the basic defect in cystic fibrosis (CF), a genetic disease that particularly affects the respiratory system, with bacterial infection and severe inflammation."