title: Stereospecific requirement of cholesterol in the function of the serotonin1A receptor.
abstract: The serotonin1A receptor is an important member of the G protein-coupled receptor (GPCR) family. It is involved in the generation and modulation of a variety of cognitive and behavioral functions and serves as a drug target. Previous work from our laboratory has established the sensitivity of the function of the serotonin1A receptor to membrane cholesterol. Solubilization of the hippocampal serotonin1A receptor utilizing the zwitterionic detergent CHAPS is accompanied by loss of cholesterol and results in reduction in specific ligand binding. Replenishment of cholesterol to solubilized membranes restores specific ligand binding to the receptor. We utilized this strategy of sterol replenishment of solubilized membranes to explore the stereospecific stringency of cholesterol for receptor function. We used two stereoisomers of cholesterol, ent-cholesterol (enantiomer of cholesterol) and epi-cholesterol (a diastereomer of cholesterol), for this purpose. Importantly, we show here that while ent-cholesterol could replace cholesterol in supporting receptor function, epi-cholesterol could not. These results imply that the requirement of membrane cholesterol for the serotonin1A receptor function is diastereospecific, yet not enantiospecific. Our results extend and help define specificity of the interaction of membrane cholesterol with the serotonin1A receptor, and represent the first report utilizing ent-cholesterol to examine stereospecificity of GPCR-cholesterol interaction.
authors.affiliation: Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500 007, India.
authors.forename: Md
authors.initials: M
authors.lastname: Jafurulla
authors.forename: Bhagyashree D
authors.initials: BD
authors.lastname: Rao
authors.forename: Sugunan
authors.initials: S
authors.lastname: Sreedevi
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Ruysschaert
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Covey
authors.forename: Amitabha
authors.initials: A
authors.lastname: Chattopadhyay
mesh_terms: D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000737:chemistry*; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000737:chemistry*; D003902:Detergents / Q000737:chemistry; D004161:Diphenylhexatriene / Q000737:chemistry; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes / Q000737:chemistry; D006624:Hippocampus / Q000737:chemistry*; D011869:Radioligand Assay; D044282:Receptor, Serotonin, 5-HT1A / Q000737:chemistry* / Q000302:isolation & purification; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism
chemical_list: D003902:Detergents; D005456:Fluorescent Dyes; D044282:Receptor, Serotonin, 5-HT1A; D004161:Diphenylhexatriene; D002784:Cholesterol
keywords: 1,6-diphenyl-1,3,5-hexatriene; 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate; 5-HT(1A) receptor; 5-hydroxytryptamine-1A receptor; 8-OH-DPAT; 8-hydroxy-2(di-N-propylamino)tetralin; BCA; CHAPS; Cholesterol; DMPC; DPH; Fluorescence anisotropy; G protein-coupled receptor; GPCR; HM; Ligand binding; MβCD; PEG; PMSF; SM; Serotonin(1A) receptor; bicinchoninic acid; diastereomer of cholesterol; dimyristoyl-sn-glycero-3-phosphocholine; enantiomer of cholesterol; ent-Cholesterol; ent-cholesterol; epi-Cholesterol; epi-cholesterol (3-epicholesterol); hippocampal membranes; methyl-β-cyclodextrin; phenylmethylsulfonyl fluoride; polyethylene glycol; solubilized membranes