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Ward JA, Romartinez-Alonso B, Kay DF, Bellamy-Carter J, Thurairajah B, Basran J, Kwon H, Leney AC, Macip S, Roversi P, Muskett FW, Doveston RG. Characterizing the protein-protein interaction between MDM2 and 14-3-3σ; proof of concept for small molecule stabilization. J Biol Chem 2024; 300:105651. [PMID: 38237679 PMCID: PMC10864208 DOI: 10.1016/j.jbc.2024.105651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/01/2023] [Accepted: 01/01/2024] [Indexed: 02/10/2024] Open
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.
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Affiliation(s)
- Jake A Ward
- Leicester Institute for Structural and Chemical Biology, University of Leicester, Leicester, UK; Mechanisms of Cancer and Aging Laboratory, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Beatriz Romartinez-Alonso
- Leicester Institute for Structural and Chemical Biology, University of Leicester, Leicester, UK; Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Danielle F Kay
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | | | - Bethany Thurairajah
- Leicester Institute for Structural and Chemical Biology, University of Leicester, Leicester, UK; School of Chemistry, University of Leicester, Leicester, UK
| | - Jaswir Basran
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Hanna Kwon
- Leicester Institute for Structural and Chemical Biology, University of Leicester, Leicester, UK; Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Aneika C Leney
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Salvador Macip
- Mechanisms of Cancer and Aging Laboratory, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK; FoodLab, Faculty of Health Sciences, Universitat Oberta de Catalunya, Barcelona, Spain; Josep Carreras Leukaemia Research Institute, Ctra de Can Ruti, Camí de les Escoles, s/n, Badalona, Barcelona, Spain
| | - Pietro Roversi
- Leicester Institute for Structural and Chemical Biology, University of Leicester, Leicester, UK; Institute of Agricultural Biology and Biotechnology, C.N.R., Unit of Milan, Milano, Italy
| | - Frederick W Muskett
- Leicester Institute for Structural and Chemical Biology, University of Leicester, Leicester, UK; Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Richard G Doveston
- Leicester Institute for Structural and Chemical Biology, University of Leicester, Leicester, UK; School of Chemistry, University of Leicester, Leicester, UK.
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Thurairajah B, Hudson AJ, Doveston RG. Contemporary biophysical approaches for studying 14-3-3 protein-protein interactions. Front Mol Biosci 2022; 9:1043673. [DOI: 10.3389/fmolb.2022.1043673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022] Open
Abstract
14-3-3 proteins are a family of regulatory hubs that function through a vast network of protein-protein interactions. Their dysfunction or dysregulation is implicated in a wide range of diseases, and thus they are attractive drug targets, especially for molecular glues that promote protein-protein interactions for therapeutic intervention. However, an incomplete understanding of the molecular mechanisms that underpin 14-3-3 function hampers progress in drug design and development. Biophysical methodologies are an essential element of the 14-3-3 analytical toolbox, but in many cases have not been fully exploited. Here, we present a contemporary review of the predominant biophysical techniques used to study 14-3-3 protein-protein interactions, with a focus on examples that address key questions and challenges in the 14-3-3 field.
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