Bioluminescence Resonance Energy Transfer Studies Reveal Constitutive Dimerization of the Human Lutropin Receptor and a Lack of Correlation between Receptor Activation and the Propensity for Dimerization

Rongbin Guan; Xiuyan Feng; Xueqing Wu; Meilin Zhang; Xuesen Zhang; Terence E Hébert; Deborah L Segaloff

doi:10.1074/jbc.M809150200

Back

Bioluminescence Resonance Energy Transfer Studies Reveal Constitutive Dimerization of the Human Lutropin Receptor and a Lack of Correlation between Receptor Activation and the Propensity for Dimerization

Journal article

Open access

Peer reviewed

Bioluminescence Resonance Energy Transfer Studies Reveal Constitutive Dimerization of the Human Lutropin Receptor and a Lack of Correlation between Receptor Activation and the Propensity for Dimerization

Rongbin Guan, Xiuyan Feng, Xueqing Wu, Meilin Zhang, Xuesen Zhang, Terence E Hébert and Deborah L Segaloff

The Journal of biological chemistry, Vol.284(12), pp.7483-7494

03/20/2009

DOI: 10.1074/jbc.M809150200

PMCID: PMC2658044

PMID: 19147490

Files and links (1)

url

https://doi.org/10.1074/jbc.M809150200View

Published (Version of record) Open Access

Abstract

Previous studies from our laboratory using co-immunoprecipitation techniques suggested that the human lutropin receptor (hLHR) constitutively self-associates into dimers/oligomers and that agonist treatment of cells either increased hLHR dimerization/oligomerization and/or stabilized hLHR dimers/oligomers to detergent solubilization (Tao, Y. X., Johnson, N. B., and Segaloff, D. L. (2004) J. Biol. Chem. 279, 5904–5914). In this study, bioluminescence resonance energy transfer (BRET 2 ) analyses confirmed that the hLHR constitutively self-associates in living cells. After subcellular fractionation, hLHR dimers/oligomers were detected in both the plasma membrane and endoplasmic reticulum (ER). Further evidence supporting the constitutive formation of hLHR dimer/oligomers in the ER is provided by data showing homodimerization of misfolded hLHR mutants that are retained in the ER. These mutants, when co-expressed with wild-type receptor, are shown by BRET 2 to heterodimerize, accounting for their dominant-negative effects on cell surface receptor expression. Hormone desorption assays using intact cells demonstrate allosterism between hLHR protomers, indicating functional cell surface hLHR dimers. However, quantitative BRET 2 analyses in intact cells indicate a lack of effect of agonist on the propensity of the hLHR to dimerize. Using purified plasma membranes, human chorionic gonadotropin was similarly observed to have no effect on the BRET 2 signal. An examination of the propensity for constitutively active and signaling inactive hLHR mutants to dimerize further showed no correlation between dimerization and the activation state of the hLHR. Taken altogether, our data suggest that hLHR dimers/oligomers are formed early in the biosynthetic pathway in the ER, are constitutively expressed on the plasma membrane, and are not affected by the activation state of the hLHR.

Mechanisms of Signal Transduction

Details

Title: Subtitle: Bioluminescence Resonance Energy Transfer Studies Reveal Constitutive Dimerization of the Human Lutropin Receptor and a Lack of Correlation between Receptor Activation and the Propensity for Dimerization
Creators: Rongbin Guan - Department of Molecular Biophysics and Physiology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and the
Xiuyan Feng - Department of Molecular Biophysics and Physiology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and the
Xueqing Wu - Department of Molecular Biophysics and Physiology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and the
Meilin Zhang - Department of Molecular Biophysics and Physiology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and the
Xuesen Zhang - Department of Molecular Biophysics and Physiology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and the
Terence E Hébert - Department of Molecular Biophysics and Physiology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and the
Deborah L Segaloff - Department of Molecular Biophysics and Physiology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and the
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.284(12), pp.7483-7494
DOI: 10.1074/jbc.M809150200
PMID: 19147490
PMCID: PMC2658044
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Publisher: American Society for Biochemistry and Molecular Biology
Language: English
Date published: 03/20/2009
Academic Unit: Molecular Physiology and Biophysics; Obstetrics and Gynecology; Medicine Administration
Record Identifier: 9984083814902771

Metrics

22 Record Views

52 Times Cited - Web of Science