CFTRproteinet

CFTRproteinet is the protein encoded by the CFTR gene in humans. It is a member of the ATP-binding cassette (ABC) transporter superfamily and functions as an ion channel that conducts chloride and bicarbonate ions across epithelial cell membranes. Its activity is regulated by cyclic AMP (cAMP)-dependent phosphorylation and ATP binding, contributing to the maintenance of proper salt and water balance on mucosal surfaces of the airways, pancreas, and gut.

CFTRproteinet comprises two transmembrane domains, two nucleotide-binding domains, and a regulatory R-domain. The transmembrane domains form the chloride pathway, while the NBDs drive channel opening through ATP binding and hydrolysis. The R-domain contains phosphorylation sites for protein kinase A that modulate activity. The protein is synthesized in the endoplasmic reticulum, glycosylated, and trafficked to the cell surface; mature protein is observed as a higher-glycosylated form (band C).

Mutations in CFTR cause cystic fibrosis (CF). The most common allele, F508del, impairs folding and trafficking, reducing surface expression. Other mutations can affect synthesis, processing, gating, or chloride conductance. CFTR dysfunction leads to thick, sticky mucus, recurrent lung infections, pancreatic insufficiency, and elevated sweat chloride; phenotypes vary with mutation class and modifier genes.

Therapies include CFTR modulators that target specific defects. Correctors (e.g., lumacaftor, tezacaftor, elexacaftor) improve trafficking, while potentiators (e.g., ivacaftor) increase channel opening. Combinations such as elexacaftor/tezacaftor/ivacaftor provide benefit for many mutations, including F508del. Research continues on gene- and mRNA-based approaches, new modulators, and complementary therapies; clinical management also emphasizes airway clearance and infection control.