par Dawaliby, Rosie 
;Fung, Juan José J.J. Fung;Kobilka, Brian K.;Govaerts, Cédric
Référence Keyston Sympsium on Molecular and Cellular Biology, Transmembrane signalling by GPCRs and Channels (23-28 January 2011: Sagebrush Inn and Conference Center, Taos, New Mexico, USA)
Publication Non publié, 2011-01
;Fung, Juan José J.J. Fung;Kobilka, Brian K.;Govaerts, Cédric Référence Keyston Sympsium on Molecular and Cellular Biology, Transmembrane signalling by GPCRs and Channels (23-28 January 2011: Sagebrush Inn and Conference Center, Taos, New Mexico, USA)
Publication Non publié, 2011-01
Poster de conférence
| Résumé : | Background: G Protein-Coupled Receptors (GPCRs) represent the largest class of membrane proteins in our genome. They are responsible for communicating extracellular information to the cell in a remarkably wide variety of metabolic processes. It is now clear that lipid-protein interactions are important modulators of membrane protein function and several studies have proposed a functional role for lipids, especially cholesterol, on the function of GPCRs. For instance it has been shown that the b2-adrenergic receptor (b2AR) preferentially localizes in cholesterol-rich caveolae (1), is stabilized by cholesterol and its crystal structure clearly shows two cholesterol molecules tightly bound on the outside of the transmembrane bundle (2). Our work aims at characterizing the role of the membrane lipid composition on the structural and functional regulation of the b2AR. By reconstituting the b2AR in proteoliposomes of given compositions, we intend to identify the effect of the different lipid species of the mammalian membrane on the receptor function (binding affinity and agonist-induced activation). Using biophysical approaches, such as fluorescence spectroscopy and Attenuated Total Reflection Fourier transformation Infrared Spectroscopy (ATR-FTIR) we characterize the conformational modulation of the b2-adrenergic receptor by specific lipid species.Results: We compared reconstitutions of b2AR in DOPC/CHS and in heart and liver lipids extracts.Preliminary data suggest that binding of b2AR to its antagonist Alprenolol is modified by the lipid composition of the proteoliposomes. Bimane Fluorescence experiments used to monitor the ionic lock changes also show that the activation and inhibition of the receptor are modulated by the lipidic environment.Perspectives: More lipid composition, not only tissues extracts but also native membrane, and given lipid mixtures. functional assays will be done, i.e. G protein coupling and oligomerization of the receptor. Finally we will record ATR-FTIR spectral profiles of stimulated and non stimulated b2AR in all lipid composition used for functional assays. This will reveal possible tertiary conformational changes and orientational changes associated with modification of the lipidic environment |
