Electron Paramagnetic Resonance Gives Evidence for the Presence of Type 1 Gonadotropin-Releasing Hormone Receptor (GnRH-R) in Subdomains of Lipid Rafts
Open Access
- 12 February 2021
- Vol. 26 (4), 973
- https://doi.org/10.3390/molecules26040973
Abstract
This study investigated the effect of type 1 gonadotropin releasing hormone receptor (GnRH-R) localization within lipid rafts on the properties of plasma membrane (PM) nanodomain structure. Confocal microscopy revealed colocalization of PM-localized GnRH-R with GM1-enriched raft-like PM subdomains. Electron paramagnetic resonance spectroscopy (EPR) of a membrane-partitioned spin probe was then used to study PM fluidity of immortalized pituitary gonadotrope cell line αT3-1 and HEK-293 cells stably expressing GnRH-R and compared it with their corresponding controls (αT4 and HEK-293 cells). Computer-assisted interpretation of EPR spectra revealed three modes of spin probe movement reflecting the properties of three types of PM nanodomains. Domains with an intermediate order parameter (domain 2) were the most affected by the presence of the GnRH-Rs, which increased PM ordering (order parameter (S)) and rotational mobility of PM lipids (decreased rotational correlation time (τc)). Depletion of cholesterol by methyl-β-cyclodextrin (methyl-β-CD) inhibited agonist-induced GnRH-R internalization and intracellular Ca2+ activity and resulted in an overall reduction in PM order; an observation further supported by molecular dynamics (MD) simulations of model membrane systems. This study provides evidence that GnRH-R PM localization may be related to a subdomain of lipid rafts that has lower PM ordering, suggesting lateral heterogeneity within lipid raft domains.Funding Information
- Javna Agencija za Raziskovalno Dejavnost RS (P4-0053, P1-0060)
This publication has 64 references indexed in Scilit:
- Membrane rafts and GnRH receptor signalingBrain Research, 2010
- Update of the CHARMM All-Atom Additive Force Field for Lipids: Validation on Six Lipid TypesThe Journal of Physical Chemistry B, 2010
- Lipid Rafts As a Membrane-Organizing PrincipleScience, 2010
- The challenge of lipid raftsJournal of Lipid Research, 2009
- Insulin augments gonadotropin-releasing hormone induction of translation in LβT2 cellsMolecular and Cellular Endocrinology, 2009
- Order of lipid phases in model and plasma membranesProceedings of the National Academy of Sciences of the United States of America, 2009
- CHARMM-GUI Membrane Builder for Mixed Bilayers and Its Application to Yeast MembranesBiophysical Journal, 2009
- Membrane lipids: where they are and how they behaveNature Reviews Molecular Cell Biology, 2008
- Structural determinants for partitioning of lipids and proteins between coexisting fluid phases in giant plasma membrane vesiclesBiochimica et Biophysica Acta (BBA) - Biomembranes, 2008
- Assessing the Nature of Lipid Raft MembranesPLoS Computational Biology, 2007