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Updated: Mar 25, 2026
Expression and Purification of the Cystic Fibrosis Transmembrane Conductance Regulator Protein in Saccharomyces cerevisiae
Published on: March 10, 2012
Characterization and small-molecule stabilization of the multisite tandem binding between 14-3-3 and the R domain of
Loes M Stevers1, Chan V Lam1, Seppe F R Leysen1
1Laboratory of Chemical Biology, Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands;
Abstract:
Cystic fibrosis is a fatal genetic disease, most frequently caused by the retention of the CFTR (cystic fibrosis transmembrane conductance regulator) mutant protein in the endoplasmic reticulum (ER). The binding of the 14-3-3 protein to the CFTR regulatory (R) domain has been found to enhance CFTR trafficking to the plasma membrane. To define the mechanism of action of this protein-protein interaction, we have examined the interaction in vitro. The disordered multiphosphorylated R domain contains nine different 14-3-3 binding motifs. Furthermore, the 14-3-3 protein forms a dimer containing two amphipathic grooves that can potentially bind these phosphorylated motifs. This results in a number of possible binding mechanisms between these two proteins. Using multiple biochemical assays and crystal structures, we show that the interaction between them is governed by two binding sites: The key binding site of CFTR (pS768) occupies one groove of the 14-3-3 dimer, and a weaker, secondary binding site occupies the other binding groove. We show that fusicoccin-A, a natural-product tool compound used in studies of 14-3-3 biology, can stabilize the interaction between 14-3-3 and CFTR by selectively interacting with a secondary binding motif of CFTR (pS753). The stabilization of this interaction stimulates the trafficking of mutant CFTR to the plasma membrane. This definition of the druggability of the 14-3-3-CFTR interface might offer an approach for cystic fibrosis therapeutics.
Insights
Cystic fibrosis treatments may improve by stabilizing the interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) and 14-3-3 proteins. This interaction enhances mutant CFTR protein transport to the cell surface.
Area of Science:
- Molecular biology
- Biochemistry
- Genetics
Background:
- Cystic fibrosis is a fatal genetic disorder.
- Mutant CFTR protein mislocalization to the ER is a primary cause.
- 14-3-3 proteins binding to CFTR enhance its plasma membrane trafficking.
Purpose of the Study:
- To elucidate the molecular mechanism of 14-3-3 and CFTR interaction.
- To investigate how this interaction can be pharmacologically modulated.
Main Methods:
- In vitro biochemical assays.
- Crystal structure analysis.
- Biochemical assays and structural studies were used to define the binding sites.
Main Results:
- The CFTR R domain has multiple 14-3-3 binding motifs.
- The 14-3-3 dimer binds CFTR via two sites: a key site (pS768) and a secondary site.
- Fusicoccin-A stabilizes the 14-3-3-CFTR interaction by binding to a secondary motif (pS753).
Conclusions:
- The 14-3-3-CFTR interaction is mediated by two distinct binding sites.
- Stabilizing this interaction with compounds like fusicoccin-A promotes mutant CFTR trafficking.
- Targeting the 14-3-3-CFTR interface offers a potential therapeutic strategy for cystic fibrosis.
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