Journal article
Revisiting and Questioning Functional Rescue between Dimerized LH Receptor Mutants
Molecular endocrinology (Baltimore, Md.), Vol.26(4), pp.655-668
04/01/2012
DOI: 10.1210/me.2011-1285
PMCID: PMC3327360
PMID: 22403174
Abstract
Abstract The glycoprotein hormone receptors are G protein-coupled receptors containing a large extracellular domain fused to a prototypical serpentine domain. cis-activation occurs when binding of hormone to the extracellular domain stabilizes the serpentine domain in an active conformation. Studies by others suggested that these receptors can also signal by trans-activation, where hormone binding to one receptor protomer activates the serpentine domain of an associated protomer, as documented by the partial rescue of hormone-dependent signaling when a binding defective mutant is coexpressed with a signaling defective mutant. However, our characterizations of several LH receptor (LHR) mutants used in previous studies differ markedly from those originally reported. Also, when examining a pair of LHR mutants previously shown to functionally rescue in vitro as well as in vivo, in addition to finding that the properties of the individual mutants differ significantly from those originally described, we determined that when this pair of mutants was coexpressed in vitro, quantitative analyses did not indicate functional rescue. Additional data are presented that provide a plausible alternate explanation for the apparent in vivo trans-activation that was reported. Finally, using LHR mutants that we have documented to be expressed at the cell surface but to lack human chorionic gonadotropin binding activity or to be severely impaired in their ability to activate Gs, we did not observe functional rescue of human chorionic gonadotropin-stimulated cAMP when the mutants were coexpressed, even though bioluminescence resonance energy transfer analyses confirmed that the coexpressed mutants formed dimers. Taken altogether, our data substantively question the concept of functional rescue between LHR mutants.
Details
- Title: Subtitle
- Revisiting and Questioning Functional Rescue between Dimerized LH Receptor Mutants
- Creators
- Meilin Zhang - Department of Molecular Physiology and Biophysics, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242Rongbin Guan - Department of Molecular Physiology and Biophysics, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242Deborah L Segaloff - Department of Molecular Physiology and Biophysics, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242
- Resource Type
- Journal article
- Publication Details
- Molecular endocrinology (Baltimore, Md.), Vol.26(4), pp.655-668
- DOI
- 10.1210/me.2011-1285
- PMID
- 22403174
- PMCID
- PMC3327360
- ISSN
- 0888-8809
- eISSN
- 1944-9917
- Language
- English
- Date published
- 04/01/2012
- Academic Unit
- Molecular Physiology and Biophysics; Obstetrics and Gynecology; Medicine Administration
- Record Identifier
- 9984083233402771
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