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Updated: Jul 14, 2026
10:51
Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists
Published on: November 16, 2013
TR surfaces and conformations required to bind nuclear receptor corepressor
Adhirai Marimuthu1, Weijun Feng, Tetsuya Tagami
1Metabolic Research Unit, University of California San Francisco, San Francisco, California 94143, USA.
Molecular Endocrinology (Baltimore, Md.)
|January 31, 2002
Summary
Researchers identified key residues for thyroid hormone receptor (TR) binding to nuclear receptor corepressor (N-CoR). This reveals new interaction sites and mechanisms for modulating corepressor binding, crucial for TR function.
Area of Science:
- Molecular Biology
- Endocrinology
- Structural Biology
Background:
- Nuclear receptors, including the thyroid hormone receptor (TR), play critical roles in gene regulation.
- Coregulators, such as nuclear receptor corepressor (N-CoR), are essential for the function of nuclear receptors.
- Understanding the precise interactions between receptors and coregulators is vital for deciphering gene regulation and developing therapeutic strategies.
Purpose of the Study:
- To identify specific residues and surfaces on the TR involved in binding N-CoR.
- To elucidate the structural basis of N-CoR binding to TR and other nuclear receptors.
- To explore mechanisms for selective modulation of corepressor interactions with nuclear receptors.
Main Methods:
- Extensive mutagenesis of the full-length human TRbeta ligand binding domain (>100 mutations).
- Assays to measure N-CoR binding affinity and selectivity.
- Analysis of N-CoR binding in TR, RXRs, and ERs, including effects of helix 12 deletion and ligand stimulation.
- Transfection assays to assess corepressor-mediated functions.
Main Results:
- A primary N-CoR interaction surface was identified, distinct from coactivator binding sites and involving a novel site beneath helix 12.
- Deletion of helix 12 significantly increased N-CoR binding across multiple nuclear receptors, indicating competitive binding.
- Two additional mutation-sensitive surfaces near helix 1 and helix 11 were identified, contributing to N-CoR binding by stabilizing unliganded conformations.
- Mutations in these three surfaces impaired corepressor-mediated functions in transfection assays.
Conclusions:
- The TR utilizes a complex surface, including a novel site, for N-CoR binding, with helix 12 playing a competitive role.
- N-CoR binding is regulated by receptor conformation, competitive interactions with helix 12, and potentially pharmacological agents.
- These findings provide a detailed map of corepressor interaction sites, enabling targeted strategies for selective modulation of nuclear receptor function.
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