Cryo-EM structures reveal the PP2A-B55α and Eya3 interaction that can be disrupted by a peptide inhibitor

Shasha Shi; Xueni Li; Christopher Alderman; Lars Wick; Wei Huang; North Foulon; Lingdi Zhang; John Rossi; Wenxin Hu; Shouqing Cui; Hongjin Zheng; Derek J Taylor; Heide L Ford; Rui Zhao

doi:10.1016/j.jbc.2025.110287

Cryo-EM structures reveal the PP2A-B55α and Eya3 interaction that can be disrupted by a peptide inhibitor

J Biol Chem. 2025 Jul;301(7):110287. doi: 10.1016/j.jbc.2025.110287. Epub 2025 May 23.

Authors

Shasha Shi¹, Xueni Li¹, Christopher Alderman², Lars Wick³, Wei Huang⁴, North Foulon⁵, Lingdi Zhang¹, John Rossi¹, Wenxin Hu⁶, Shouqing Cui⁴, Hongjin Zheng⁷, Derek J Taylor⁴, Heide L Ford⁸, Rui Zhao⁹

Affiliations

¹ Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
² Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
³ Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Cancer Biology Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
⁴ Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA.
⁵ Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
⁶ Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
⁷ Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
⁸ Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Cancer Biology Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
⁹ Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Molecular Biology Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Cancer Biology Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA. Electronic address: rui.zhao@cuanschutz.edu.

Abstract

We have previously shown that Eya3 recruits PP2A-B55α to dephosphorylate pT58 on Myc, increasing Myc stability and enhancing primary tumor growth of triple-negative breast cancer (TNBC). However, the molecular details of how Eya3 recruits PP2A-B55α remain unclear. Here, we determined the cryo-EM structures of PP2A-B55α bound with Eya3, with an inhibitory peptide B55i, and in its unbound state. These studies demonstrate that Eya3 binds B55α through an extended peptide in the N-terminal domain of Eya3. The Eya3 peptide, PP2A-B55α substrates, and protein-peptide inhibitors including B55i bind to a similar area on the B55α surface, but the molecular details of the binding differ. We further demonstrated that the B55i peptide inhibits the B55α and Eya3 interaction in vitro. The B55i peptide expressed on a plasmid increases Myc pT58 and decreases Myc protein levels in TNBC cells, suggesting the potential of B55i or similar peptides as therapies for TNBC.

Keywords: B55; cancer; eya3; peptide inhibitor; protein phosphatase 2A.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Cell Line, Tumor
Cryoelectron Microscopy
DNA-Binding Proteins
Humans
Peptides* / chemistry
Peptides* / metabolism
Peptides* / pharmacology
Protein Binding
Protein Phosphatase 2* / antagonists & inhibitors
Protein Phosphatase 2* / chemistry
Protein Phosphatase 2* / genetics
Protein Phosphatase 2* / metabolism
Protein Tyrosine Phosphatases* / chemistry
Protein Tyrosine Phosphatases* / metabolism
Proto-Oncogene Proteins c-myc / metabolism
Triple Negative Breast Neoplasms / metabolism

Substances

Peptides
EYA3 protein, human
Protein Phosphatase 2
Proto-Oncogene Proteins c-myc
Protein Tyrosine Phosphatases
DNA-Binding Proteins

Associated data

PDB/9MZW
PDB/9N0Z
PDB/9N0Y

Abstract

Publication types

MeSH terms

Substances

Associated data

Grants and funding