Related Experiment Video

Updated: Sep 20, 2026

Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay
09:07

Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay

Published on: December 19, 2018

Modulation of estrogen receptor activity by selective coregulators

Paolo G V Martini1, Benita S Katzenellenbogen

  • 1Department of Molecular and Integrative Physiology, College of Medicine, University of Illinois, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, IL 61801, USA.

The Journal of Steroid Biochemistry and Molecular Biology
|August 29, 2003
PubMed

Insights

Researchers discovered a new protein, repressor of estrogen receptor activity (REA), that selectively inhibits estrogen receptor (ER) activity. Prothymosin-alpha (PTalpha) counteracts REA, highlighting their roles in modulating ER specificity.

Area of Science:

  • Molecular Biology
  • Endocrinology
  • Cancer Research

Background:

  • Estrogen receptor (ER) is a key target in breast cancer therapy.
  • ER mediates estrogen and antiestrogen effects in target cells.
  • Inactivating ER is a strategy to suppress cancer growth.

Purpose of the Study:

  • Identify novel regulators of estrogen receptor (ER) activity.
  • Investigate the mechanism of selective ER repression.
  • Explore the role of new proteins in modulating nuclear receptor function.

Main Methods:

  • Two-hybrid screening to identify interacting proteins.
  • Assays to measure transcriptional activity of nuclear receptors.
  • Analysis of protein-protein interactions.

Main Results:

  • Identified a selective repressor of estrogen receptor activity (REA).
  • REA is recruited to the hormone-occupied ER, repressing its activity.
  • Prothymosin-alpha (PTalpha) enhances ER activity by displacing REA.

Conclusions:

  • REA selectively represses ER transcriptional activity.
  • PTalpha enhances ER activity by modulating REA binding.
  • REA and PTalpha act as novel modulators conferring ER specificity.

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