title: Membrane cholesterol access into a G-protein-coupled receptor.
abstract: Cholesterol is a key component of cell membranes with a proven modulatory role on the function and ligand-binding properties of G-protein-coupled receptors (GPCRs). Crystal structures of prototypical GPCRs such as the adenosine A2Areceptor (A2AR) have confirmed that cholesterol finds stable binding sites at the receptor surface suggesting an allosteric role of this lipid. Here we combine experimental and computational approaches to show that cholesterol can spontaneously enter the A2AR-binding pocket from the membrane milieu using the same portal gate previously suggested for opsin ligands. We confirm the presence of cholesterol inside the receptor by chemical modification of the A2AR interior in a biotinylation assay. Overall, we show that cholesterol's impact on A2AR-binding affinity goes beyond pure allosteric modulation and unveils a new interaction mode between cholesterol and the A2AR that could potentially apply to other GPCRs.
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain.|Institut für Medizinische Physik und Biophysik, AG ProteiInformatics, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.
authors.forename: Ramon
authors.initials: R
authors.lastname: Guixà-González
authors.affiliation: Department of Inorganic Chemistry, Organic Chemistry, and Biochemistry, Faculty of Science and Chemical Technologies and Faculty of Medicine of Ciudad Real. Regional Center of Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), 13071 Ciudad Real, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Albasanz
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain.
authors.forename: Ismael
authors.identifier: 0000-0002-1602-8679
authors.initials: I
authors.lastname: Rodriguez-Espigares
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Pastor
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain.
authors.forename: Ferran
authors.initials: F
authors.lastname: Sanz
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Martí-Solano
authors.affiliation: Department of Physics, Tampere University of Technology (TUT), PO Box 692, FI-33101 Tampere, Finland.
authors.forename: Moutusi
authors.initials: M
authors.lastname: Manna
authors.affiliation: Department of Physics, Tampere University of Technology (TUT), PO Box 692, FI-33101 Tampere, Finland.|Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, CZ-16610 Prague, Czech Republic.
authors.forename: Hector
authors.identifier: 0000-0001-9716-1713
authors.initials: H
authors.lastname: Martinez-Seara
authors.affiliation: Institut für Medizinische Physik und Biophysik, AG ProteiInformatics, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Hildebrand
authors.affiliation: Department of Inorganic Chemistry, Organic Chemistry, and Biochemistry, Faculty of Science and Chemical Technologies and Faculty of Medicine of Ciudad Real. Regional Center of Biomedical Research (CRIB), University of Castilla-La Mancha (UCLM), 13071 Ciudad Real, Spain.
authors.forename: Mairena
authors.initials: M
authors.lastname: Martín
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain.
authors.forename: Jana
authors.initials: J
authors.lastname: Selent
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D002784:Cholesterol / Q000737:chemistry* / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D000072417:Protein Domains; D051381:Rats; D043705:Receptor, Adenosine A2A / Q000737:chemistry / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry* / Q000378:metabolism
chemical_list: D043705:Receptor, Adenosine A2A; D043562:Receptors, G-Protein-Coupled; D002784:Cholesterol