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Updated: Aug 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

The molecular mechanisms of coactivator utilization in ligand-dependent transactivation by the androgen receptor

Eva Estébanez-Perpiñá1, Jamie M R Moore, Ellena Mar

  • 1Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143, USA.

The Journal of Biological Chemistry
|November 26, 2004
PubMed

Insights

Androgen receptor (AR) ligand-binding domain binds unique aromatic motifs and specific leucine-rich motifs. These interactions are crucial for coactivator recruitment and AR-driven gene transcription.

Area of Science:

  • Molecular Biology
  • Endocrinology
  • Structural Biology

Background:

  • Androgens regulate critical physiological processes via the androgen receptor (AR).
  • AR's ligand-binding domain (LBD) typically interacts with coactivators to modulate gene expression.
  • Current understanding suggested AR's LBD primarily uses aromatic-rich (FXXLF) motifs, distinct from other nuclear receptors using leucine-rich (LXXLL) motifs.

Purpose of the Study:

  • To investigate the interaction of the AR-LBD with both FXXLF and LXXLL motifs.
  • To determine the role of these interactions in AR-mediated transcriptional regulation.
  • To elucidate the structural basis for AR's differential coactivator binding.

Main Methods:

  • Co-immunoprecipitation assays to study protein interactions.
  • Reporter gene assays to assess transcriptional activity.
  • X-ray crystallography to determine the structure of AR-LBD complexes.

Main Results:

  • The AR-LBD directly interacts with both FXXLF and a subset of LXXLL motifs.
  • Binding to specific LXXLL motifs is necessary and sufficient for steroid receptor coactivator (SRC)-mediated AR transcriptional regulation.
  • Crystal structures reveal unique AR-LBD side chain rearrangements to accommodate FXXLF or LXXLL motifs, with flanking sequences aiding discrimination.

Conclusions:

  • The AR-LBD employs a dual-motif strategy for coactivator recruitment, utilizing both FXXLF and specific LXXLL motifs.
  • This flexible binding mechanism allows AR to recruit different coactivators, including SRCs, for precise transcriptional control.
  • Structural insights highlight the adaptability of the AR-LBD in mediating gene regulation.

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