Related Experiment Video
Updated: Jul 31, 2026

In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes
Published on: August 13, 2012
The amino-terminal portion of CFTR forms a regulated Cl- channel
D N Sheppard1, L S Ostedgaard, D P Rich
1Howard Hughes Medical Institute, Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
Abstract:
The cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel consists of two motifs (each containing a membrane-spanning domain [MSD] and a nucleotide-binding domain [NBD]) linked by an R domain. We tested the hypothesis that one MSD-NBD motif could form a Cl- channel. The amino-terminal portion of CFTR (D836X, which contains MSD1, NBD1, and the R domain) formed Cl- channels with conductive properties identical to those of CFTR. However, channel regulation differed. Although phosphorylation increased activity, channels opened without phosphorylation. MgATP stimulated D836X more potently than CFTR and may interact at more than one site. These data and migration of D836X on sucrose density gradients suggest that D836X may function as a multimer. Thus, the amino-terminal portion of CFTR contains all of the structures required to build a regulated Cl- channel.
Related Concept Videos
Insertion of Single-pass Transmembrane Proteins in the RER
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Protein Translocation Machinery on the ER Membrane
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation, but...
Reabsorption and Secretion in the PCT
Transport mechanisms involving sodium ions (Na+) contribute significantly to solute reabsorption. These mechanisms include symport and antiport processes.
A key example is the...
Reabsorption and Secretion in the Loop of Henle
Reabsorption and Secretion in the DCT and Collecting Duct
The distal part of the DCT, along with the...

