Characterizing the protein–protein interaction between MDM2 and 14-3-3σ; proof of concept for small molecule stabilization

DOI: 10.1016/j.jbc.2024.105651

Authors: Jake A. Ward (University of Leicester) , Beatriz Romartinez-Alonso (University of Leicester) , Danielle F. Kay (University of Birmingham) , Jeddidiah Bellamy-Carter (University of Birmingham) , Bethany Thurairajah (University of Leicester) , Jaswir Basran (University of Leicester) , Hanna Kwon (University of Leicester) , Aneika C. Leney (University of Birmingham) , Salvador Macip (University of Leicester; Universitat Oberta de Catalunya; Josep Carreras Leukaemia Research Institute) , Pietro Roversi (University of Leicester; Institute of Agricultural Biology and Biotechnology, C.N.R.) , Frederick W. Muskett (University of Leicester) , Richard G. Doveston (University of Leicester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Biological Chemistry , VOL 300

State: Published (Approved)
Published: February 2024
Diamond Proposal Number(s): 26803

Abstract: Mouse Double Minute 2 (MDM2) is a key negative regulator of the tumor suppressor protein p53. MDM2 overexpression occurs in many types of cancer and results in the suppression of WT p53. The 14-3-3 family of adaptor proteins are known to bind MDM2 and the 14-3-3σ isoform controls MDM2 cellular localization and stability to inhibit its activity. Therefore, small molecule stabilization of the 14-3-3σ/MDM2 protein–protein interaction (PPI) is a potential therapeutic strategy for the treatment of cancer. Here, we provide a detailed biophysical and structural characterization of the phosphorylation-dependent interaction between 14-3-3σ and peptides that mimic the 14-3-3 binding motifs within MDM2. The data show that di-phosphorylation of MDM2 at S166 and S186 is essential for high affinity 14-3-3 binding and that the binary complex formed involves one MDM2 di-phosphorylated peptide bound to a dimer of 14-3-3σ. However, the two phosphorylation sites do not simultaneously interact so as to bridge the 14-3-3 dimer in a ‘multivalent’ fashion. Instead, the two phosphorylated MDM2 motifs ‘rock’ between the two binding grooves of the dimer, which is unusual in the context of 14-3-3 proteins. In addition, we show that the 14-3-3σ–MDM2 interaction is amenable to small molecule stabilization. The natural product fusicoccin A forms a ternary complex with a 14-3-3σ dimer and an MDM2 di-phosphorylated peptide resulting in the stabilization of the 14-3-3σ/MDM2 PPI. This work serves as a proof-of-concept of the drugability of the 14-3-3/MDM2 PPI and paves the way toward the development of more selective and efficacious small molecule stabilizers.

Journal Keywords: protein protein interaction; 14-3-3 proteins; MDM2; p53; molecular glue

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: I04-Macromolecular Crystallography

Added On: 21/02/2024 13:28

Documents:
1-s2.0-S0021925824000279-main.pdf

Discipline Tags:

Non-Communicable Diseases Health & Wellbeing Cancer Biochemistry Chemistry Structural biology Biophysics Drug Discovery Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)