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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
Revisiting and questioning functional rescue between dimerized LH receptor mutants.
Meilin Zhang1, Rongbin Guan, Deborah L Segaloff
1Department of Molecular Physiology and Biophysics, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52246, USA.
Molecular Endocrinology (Baltimore, Md.)
|March 10, 2012
Summary
Functional rescue in luteinizing hormone receptor (LHR) mutants is questioned. Data suggest that apparent trans-activation may be explained by alternative mechanisms, challenging prior findings on LHR mutant signaling.
Area of Science:
- Biochemistry
- Molecular Biology
- Endocrinology
Background:
- Glycoprotein hormone receptors are G protein-coupled receptors involved in hormone signaling.
- Trans-activation, where one receptor protomer activates another, has been proposed for these receptors.
- Previous studies suggested functional rescue between luteinizing hormone receptor (LHR) mutants.
Purpose of the Study:
- To re-evaluate the phenomenon of functional rescue between LHR mutants.
- To investigate the proposed mechanism of trans-activation in LHR signaling.
- To clarify the signaling properties of specific LHR mutants.
Main Methods:
- Characterization of LHR mutants with altered binding and signaling capabilities.
- Coexpression of LHR mutants in vitro to assess functional rescue.
- Bioluminescence resonance energy transfer (BRET) to confirm receptor dimerization.
- Quantitative analyses of hormone-stimulated cAMP production.
Main Results:
- Properties of previously studied LHR mutants differed from original reports.
- Coexpression of a pair of LHR mutants did not result in functional rescue in vitro.
- Apparent in vivo trans-activation could be explained by alternative mechanisms.
- Coexpressed LHR mutants, confirmed to dimerize, did not show functional rescue of hCG-stimulated cAMP.
Conclusions:
- The concept of functional rescue between LHR mutants is substantively questioned by the data.
- The proposed mechanism of trans-activation in LHR signaling requires re-evaluation.
- The signaling behavior of LHR mutants is complex and may not support simple rescue models.
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