cAMP-Inducible Chloride Conductance in Mouse Fibroblast Lines Stably Expressing the Human Cystic Fibrosis Transmembrane Conductance Regulator

• Published in: Proceedings of the National Academy of Sciences - PNAS 1991-09, Vol.88 (17), p.7500-7504
• Main Authors: ROMMENS, J. M, DHO, S, BEAR, C. E, KARTNER, N, KENNEDY, D, RIORDAN, J. R, LAP-CHEE TSUI, KEVIN FOSKETT, J
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Biological and medical sciences; Cell Line; Cell physiology; chloride; Chloride Channels; Chlorides - metabolism; Cloning, Molecular; Codon - genetics; Cyclic AMP - physiology; Cystic Fibrosis - genetics; Cystic Fibrosis - physiopathology; Cystic Fibrosis Transmembrane Conductance Regulator; electric currents; Exons; Fibroblasts - physiology; Fundamental and applied biological sciences. Psychology; Gene Expression; Genetic Vectors; Humans; Ion Channels - physiology; Kinetics; Membrane and intracellular transports; Membrane Proteins - genetics; Membrane Proteins - physiology; Metallothionein - genetics; Mice; Molecular and cellular biology; Molecular Sequence Data; Mutagenesis, Site-Directed; Oligonucleotide Probes; Plasmids; Promoter Regions, Genetic; Restriction Mapping; Transfection
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.88.17.7500

A cAMP-inducible chloride permeability has been detected in mouse fibroblast (L cell) lines upon stable integration of a full-length cDNA encoding the human cystic fibrosis transmembrane conductance regulator (CFTR). As indicated by a Cl-indicator dye, the Cl-permeability of the plasma membrane increases by 10- to 30-fold within 2 min after treatment of the cells with forskolin, an activator of adenylyl cyclase. The properties of the conductance are similar to those described in secretory epithelial cells; the whole-cell current-voltage relationship is linear and there is no evidence of voltage-dependent inactivation or activation. In contrast, this cAMP-dependent Cl-flux is undetectable in the untransfected cells or cells harboring defective cDNA constructs, including one with a phenylalanine deletion at amino acid position 508 (ΔF508), the most common mutation causing cystic fibrosis. These observations are consistent with the hypothesis that the CFTR is a cAMP-dependent Cl-channel. The availability of a heterologous (nonepithelial) cell type expressing the CFTR offers an excellent system to understand the basic mechanisms underlying this CFTR-associated ion permeability and to study the structure and function of the CFTR.