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Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists
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The antiestrogen ICI 182780 disrupts estrogen receptor nucleocytoplasmic shuttling

S Dauvois1, R White, M G Parker

  • 1Molecular Endocrinology Laboratory, Imperial Cancer Research Fund, Lincoln's Inn Fields, London, UK.

Journal of Cell Science
|December 1, 1993
PubMed

Insights

The mouse estrogen receptor continuously moves between the nucleus and cytoplasm. Pure antiestrogens block this shuttling by preventing nuclear entry, impacting estrogen receptor function.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Endocrinology

Background:

  • The estrogen receptor (ER) plays a crucial role in cellular processes.
  • Understanding ER's subcellular localization and dynamics is key to its function.
  • ER shuttling between the nucleus and cytoplasm influences gene regulation.

Purpose of the Study:

  • To investigate the nucleocytoplasmic shuttling of the mouse estrogen receptor.
  • To determine the effect of estradiol and antiestrogens on ER localization.
  • To elucidate the mechanism by which antiestrogens affect ER shuttling.

Main Methods:

  • Heterokaryon assays to monitor protein transfer between nuclei.
  • Analysis of subcellular distribution of wild-type and mutant estrogen receptors.
  • Treatment with estradiol, 4-hydroxytamoxifen (partial antiestrogen), and ICI 182780 (pure antiestrogen).

Main Results:

  • Estrogen receptor exhibits constant nucleocytoplasmic shuttling, predominantly residing in the nucleus at steady-state.
  • The partial antiestrogen 4-hydroxytamoxifen retained the receptor in the nucleus.
  • The pure antiestrogen ICI 182780 caused cytoplasmic accumulation by inhibiting nuclear uptake, thus blocking shuttling.
  • Ligand binding is not essential for ER shuttling but can be disrupted by pure antiestrogens.

Conclusions:

  • Estrogen receptor shuttling is an intrinsic property independent of ligand binding.
  • Pure antiestrogens like ICI 182780 disrupt ER function by inhibiting nucleocytoplasmic transport.
  • Understanding ER dynamics provides insights into endocrine signaling and therapeutic strategies.

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