Design of Peptide Ligands for 14-3-3ε, and Exploring the Role of Residue Types in Ligand Recognition by 14-3-3 Proteins
type: CreativeWork
description: The 14-3-3 family of proteins are implicated in various malignancies. In cutaneous squamous cell carcinoma (cSCC), overexpression of the 14-3-3ε isoform is associated with suppression of apoptosis. Like 14-3-3ε, the protein phosphatase cell division cycle 25 A (CDC25A) is over expressed and mislocalized from nucleus to cytoplasm in cSCC. The anti-apoptosis activity of 14-3-3ε is dependent on its interaction with cytoplasmic CDC25A. Thus, inhibiting interaction between 14-3-3ε and CDC25A is an attractive target for promoting apoptosis in cSCC. Previously, this group developed two novel, 14 amino acid residue peptides; Ac-CDC25A(173-186)-NH2 (pS), and Ac-CDC25A(502-515)-NH2 (pT), corresponding to two binding regions of CDC25A to 14-3-3 proteins. Both pS and pT bind 14-3-3ε, and induce cell death of cSCC cells, albeit at a high IC50. In the work presented herein, we optimized the structure of pS and pT peptides to improve their binding affinities for 14-3-3ε. We hypothesized that shortening the pS and pT, and modifying the shortened peptides at key positions would improve their binding affinities for 14-3-3ε. To this end, pS and pT peptides were sequentially truncated from both N- and C- termini to obtain shorter analogs that still bind 14-3-3ε. On basis of preferential binding motifs of 14-3-3 proteins and computational alanine scanning, the shortened peptides were modified by introducing either aromatic or positively charged amino acid residues at key positions. Molecular dynamics (MD) simulations revealed that the 9 amino acid residue peptide analogs of pS and pT, pS(174-182), and pT(502-510), respectively, formed stable complexes with 14-3-3ε. Surface plasmon resonance showed that the pT(502-510) bound 14-3-3ε with nanomolar affinity, while the pS(174-182) had a low micromolar affinity for 14-3-3ε. Introducing aromatic amino acid residues in key positions led to further improvement in affinity of the peptides for 14-3-3ε. The peptide candidates were optimized again…
abstract: The 14-3-3 family of proteins are implicated in various malignancies. In cutaneous squamous cell carcinoma (cSCC), overexpression of the 14-3-3ε isoform is associated with suppression of apoptosis. Like 14-3-3ε, the protein phosphatase cell division cycle 25 A (CDC25A) is over expressed and mislocalized from nucleus to cytoplasm in cSCC. The anti-apoptosis activity of 14-3-3ε is dependent on its interaction with cytoplasmic CDC25A. Thus, inhibiting interaction between 14-3-3ε and CDC25A is an attractive target for promoting apoptosis in cSCC. Previously, this group developed two novel, 14 amino acid residue peptides; Ac-CDC25A(173-186)-NH2 (pS), and Ac-CDC25A(502-515)-NH2 (pT), corresponding to two binding regions of CDC25A to 14-3-3 proteins. Both pS and pT bind 14-3-3ε, and induce cell death of cSCC cells, albeit at a high IC50. In the work presented herein, we optimized the structure of pS and pT peptides to improve their binding affinities for 14-3-3ε. We hypothesized that shortening the pS and pT, and modifying the shortened peptides at key positions would improve their binding affinities for 14-3-3ε. To this end, pS and pT peptides were sequentially truncated from both N- and C- termini to obtain shorter analogs that still bind 14-3-3ε. On basis of preferential binding motifs of 14-3-3 proteins and computational alanine scanning, the shortened peptides were modified by introducing either aromatic or positively charged amino acid residues at key positions. Molecular dynamics (MD) simulations revealed that the 9 amino acid residue peptide analogs of pS and pT, pS(174-182), and pT(502-510), respectively, formed stable complexes with 14-3-3ε. Surface plasmon resonance showed that the pT(502-510) bound 14-3-3ε with nanomolar affinity, while the pS(174-182) had a low micromolar affinity for 14-3-3ε. Introducing aromatic amino acid residues in key positions led to further improvement in affinity of the peptides for 14-3-3ε. The peptide candidates were optimized again…
author: Kamayirese, Seraphine
language: en_US
keywords: 14-3-3 Proteins, Binding Motif, Biophysics, MD Simulations, Phosphate Mimics, Phosphopeptides
date published: 2024
date modified: 2026-07-24T01:51:52Z
provider: Creighton University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Creighton University