PDBsum entry 5d2d

Peptide binding protein

PDB id: 5d2d

Contents

Protein chains

229 a.a.

19 a.a.

Ligands

GLC-FRU ×2

Metals

_CL ×4

Waters ×196

References listed in PDB file

Key reference

• Title: Characterization and small-Molecule stabilization of the multisite tandem binding between 14-3-3 and the r domain of cftr.
• Authors: L.M.Stevers, C.V.Lam, S.F.Leysen, F.A.Meijer, D.S.Van scheppingen, R.M.De vries, G.W.Carlile, L.G.Milroy, D.Y.Thomas, L.Brunsveld, C.Ottmann.
• Ref.: Proc Natl Acad Sci U S A, 2016, 113, E1152. [DOI no: 10.1073/pnas.1516631113]
• PubMed id: 26888287

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.