Abstract
Cholesterol is a major component of mammalian plasma membranes that not only affects the physical properties of the lipid bilayer but also is the function of many membrane proteins including G protein-coupled receptors. The oxytocin receptor (OXTR) is involved in parturition and lactation of mammals and in their emotional and social behaviors. Cholesterol acts on OXTR as an allosteric modulator inducing a high-affinity state for orthosteric ligands through a molecular mechanism that has yet to be determined. Using the ion channel-coupled receptor technology, we developed a functional assay of cholesterol modulation of G protein-coupled receptors that is independent of intracellular signaling pathways and operational in living cells. Using this assay, we discovered a stable binding of cholesterol molecules to the receptor when it adopts an orthosteric ligand-bound state. This stable interaction preserves the cholesterol-dependent activity of the receptor in cholesterol-depleted membranes. This mechanism was confirmed using time-resolved FRET experiments on WT OXTR expressed in CHO cells. Consequently, a positive cross-regulation sequentially occurs in OXTR between cholesterol and orthosteric ligands.
Original language | English |
---|---|
Article number | 100059 |
Journal | Journal of Lipid Research |
Volume | 62 |
Early online date | 26 Feb 2021 |
DOIs | |
Publication status | Published - 31 Dec 2021 |
Bibliographical note
Funding Information:I.B.S. acknowledges integration into the Interdisciplinary Research Institute of Grenoble (IRIG, CEA). The authors thank Alexeï Grichine (Optical Microscopy - Cell Imaging facility (Microcell) from the Institute for Advanced Biosciences, Grenoble, France). The confocal microscope was partly funded by the Association for Research on Cancer, French Ministry “Enseignement Supérieur et Recherche” and the Rhone-Alpes region (CPER 2007–2013). They thank Hervé Pointu, Soumala-maya Bama Toupet, Irène Jeannin, and Charlène Caloud for the management and the maintenance of Xenopus and acknowledges the platform supported by GRAL, financed within the University Grenoble Alpes graduate school (Ecoles Universitaires de Recherche) CBH-EUR-GS (ANR-17-EURE-0003). They thank Justine Magnat for the technical support of this study. They thank Simon Harris and Karen Callahan for correcting the manuscript and Michel Vivaudou for the development of software for data analysis (76). L. D. is a SNI (Sistema Nacional de Investigadores; ANII, Uruguay) researcher and acknowledges ANII and the Institut Pasteur de Montevideo for providing the funding for his current postdoctoral position. They acknowledge PRACE for awarding them access to computational resources in ARCHER the UK National Supercomputing Service (http://www.archer.ac.uk), the PDC Centre for High Performance Computing (PDC-HPC), CINECA under the ISCRA initiative, and Jülich Supercomputing Centre. TR-FRET experiments on WT OXTR were made possible thanks to the Platform Arpège of Montpellier and the Region Languedoc-Roussillon.
Funding Information:
This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 682286) to C. J. M. This work was also supported by grants from the French Agency ANSES (EST-16-66) to C. J. M and by studentships to L. L. from the Commissariat à l'énergie atomique et aux énergies alternatives, from the National Institutes of Health (grant R01 GM089857) to V. C. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2021 THE AUTHORS.
Keywords
- Allosteric regulation
- Cholesterol
- Cholesterol binding
- Cholesterol/physical chemistry
- Lipid rafts
- Membrane protein-lipid interaction
- Molecular biology
- Oxytocin G protein-coupled receptor
- Receptors/plasma membrane
- Receptors/seven transmembrane domain
ASJC Scopus subject areas
- Biochemistry
- Endocrinology
- Cell Biology