Rescue of expression and signaling of human luteinizing hormone G protein-coupled receptor mutants with an allosterically binding small-molecule agonist

Claire L. Newton, Adele M. Whay, Craig A. McArdle, Meilin Zhang, Chris J. Van Koppen, Ruud Van De Lagemaat, Deborah L. Segaloff, Robert P. Millar

Research output: Contribution to journalArticlepeer-review

83 Scopus citations

Abstract

Naturally occurring mutations of G protein-coupled receptors (GPCRs) causing misfolding and failure to traffic to the cell surface can result in disease states. Some small-molecule orthosteric ligands can rescue such misfolded receptors, presumably by facilitating their correct folding and shuttling to the plasma membrane. Here we show that a cell-permeant, allosterically binding smallmolecule agonist (Org 42599) rescues the folding and cell surface expression, and therefore target cell signaling, of mutant human luteinizing hormone (LH) receptors (A593P and S616Y) that cause Leydig cell hypoplasia in man. Both mutant receptors were retained in the cytoplasm whereas WT receptor localized at the cell membrane, and binding of LH to cells expressing the mutant receptors was markedly lower than to those expressing the WT receptor. Incubation with Org 42599 increased mutant receptor expression, cell surface localization, and the proportion of mutant receptor in the mature glycosylated form. Importantly, although LH stimulated little (S616Y) or no (A593P) activation of cells expressing mutant receptors, incubation of cells with Org 42599 facilitated rescue of expression and stimulation by the native ligand, LH. Although Org 42599 could activate these receptors, it could not displace 125I-labeled human LH binding to the WT receptor, indicating that it acts in an allosteric manner. Here we demonstrate a small-molecule GPCR allosteric agonist that functionally rescues intracellularly retained mutant LH receptors by facilitating their cell surface expression. This approach may have application for treatment of infertile patients bearing such mutations and, more broadly, for other misfolded GPCR mutants resulting in human pathologic processes.

Original languageEnglish
Pages (from-to)7172-7176
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number17
DOIs
StatePublished - 26 Apr 2011
Externally publishedYes

Keywords

  • Infertility
  • Pharmacological chaperone
  • Receptor trafficking

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