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Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay
Published on: December 19, 2018
Ligands specify estrogen receptor alpha nuclear localization and degradation
Silvia Kocanova1, Mahta Mazaheri, Stéphanie Caze-Subra
1Université de Toulouse; UPS; Laboratoire de Biologie Moléculaire Eucaryote; F-31062 Toulouse, France.
BMC Cell Biology
|December 15, 2010
Summary
Ligand structure dictates estrogen receptor alpha's nuclear fate and protein turnover. This impacts antiestrogen drug development for breast cancer treatment.
Area of Science:
- Molecular Biology
- Cell Biology
- Pharmacology
Background:
- Estrogen receptor alpha (ERα) is primarily nuclear, with its distribution affected by agonists.
- The impact of various antiestrogens on ERα's cellular fate remains debated.
Purpose of the Study:
- To investigate the intracellular distribution of ligand-bound ERα.
- To understand how different antiestrogens influence ERα localization and stability.
Main Methods:
- Utilized a MCF-7 cell line stably expressing GFP-tagged ERα (SK19).
- Employed digitonin-based cell fractionation, fluorescence, and immuno-electron microscopy.
- Analyzed ERα localization, protein levels, and mRNA expression (ESR1) following ligand treatment.
Main Results:
- Both endogenous and GFP-ERα formed nuclear focal accumulations with agonists (E2) and pure antagonists (SERDs).
- Partial antagonists (SERMs) resulted in diffuse nuclear staining.
- SERMs stabilized ERα in the nuclear soluble fraction, while SERDs led to drastic protein reduction and sequestration in the nuclear insoluble fraction.
- E2 and SERDs induced ERα degradation in nuclear foci containing the proteasome.
Conclusions:
- Ligand chemical structure directly influences ERα's nuclear fate and protein turnover, independent of transcriptional effects.
- Findings offer a molecular basis for selecting antiestrogen compounds in breast cancer pharmacotherapy.
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