Title:Overcoming the Challenges of Detecting GPCR Oligomerization in the
Brain
Volume: 20
Issue: 6
Author(s): Víctor Fernández-Dueñas*, Jordi Bonaventura, Ester Aso, Rafael Luján, Sergi Ferré and Francisco Ciruela*
Affiliation:
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences,
Institute of Neurosciences, University of Barcelona, 08907 L’Hospitalet de Llobregat, Spain
- Neuropharmacology
& Pain Group, Neuroscience Program, Bellvitge Institute for Biomedical Research, 08907 L’Hospitalet de Llobregat,
Spain
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences,
Institute of Neurosciences, University of Barcelona, 08907 L’Hospitalet de Llobregat, Spain
- Neuropharmacology
& Pain Group, Neuroscience Program, Bellvitge Institute for Biomedical Research, 08907 L’Hospitalet de Llobregat,
Spain
Keywords:
GPCR oligomerization, immunoelectron microscopy, proximity ligation assay, TR-FRET, ALPHA assay, RET.
Abstract: G protein-coupled receptors (GPCRs) constitute the largest group of membrane receptor
proteins controlling brain activity. Accordingly, GPCRs are the main target of commercial drugs for
most neurological and neuropsychiatric disorders. One of the mechanisms by which GPCRs regulate
neuronal function is by homo- and heteromerization, with the establishment of direct protein-protein
interactions between the same and different GPCRs. The occurrence of GPCR homo- and heteromers
in artificial systems is generally well accepted, but more specific methods are necessary to address
GPCR oligomerization in the brain. Here, we revise some of the techniques that have mostly
contributed to reveal GPCR oligomers in native tissue, which include immunogold electron microscopy,
proximity ligation assay (PLA), resonance energy transfer (RET) between fluorescent ligands
and the Amplified Luminescent Proximity Homogeneous Assay (ALPHA). Of note, we use the archetypical
GPCR oligomer, the adenosine A2A receptor (A2AR)-dopamine D2 receptor (D2R) heteromer
as an example to illustrate the implementation of these techniques, which can allow visualizing
GPCR oligomers in the human brain under normal and pathological conditions. Indeed, GPCR
oligomerization may be involved in the pathophysiology of neurological and neuropsychiatric disorders.