title: Stimulation- and palmitoylation-dependent changes in oligomeric conformation of serotonin 5-HT1A receptors.
abstract: In the present study we analyzed the oligomerization state of the serotonin 5-HT1A receptor and studied oligomerization dynamics in living cells. We also investigated the role of receptor palmitoylation in this process. Biochemical analysis performed in neuroblastoma N1E-115 cells demonstrated that both palmitoylated and non-palmitoylated 5-HT1A receptors form homo-oligomers and that the prevalent receptor species at the plasma membrane are dimers. A combination of an acceptor-photobleaching FRET approach with fluorescence lifetime measurements verified the interaction of CFP- and YFP-labeled wild-type as well as acylation-deficient 5-HT1A receptors at the plasma membrane of living cells. Using a novel FRET technique based on the spectral analysis we also confirmed the specific nature of receptor oligomerization. The analysis of oligomerization dynamics revealed that apparent FRET efficiency measured for wild-type oligomers significantly decreased in response to agonist stimulation, and our combined results suggest that this decrease was mediated by accumulation of FRET-negative complexes rather than by dissociation of oligomers to monomers. In contrast, the agonist-mediated decrease of FRET signal was completely abolished in oligomers composed by non-palmitoylated receptor mutants, demonstrating the importance of palmitoylation in modulation of the structure of oligomers.
authors.affiliation: DFG-Research Center for the Molecular Physiology of the Brain (CMPB), University of Göttingen, Germany.
authors.forename: Fritz
authors.initials: F
authors.lastname: Kobe
authors.forename: Ute
authors.initials: U
authors.lastname: Renner
authors.forename: Andrew
authors.initials: A
authors.lastname: Woehler
authors.forename: Jakub
authors.initials: J
authors.lastname: Wlodarczyk
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Papusheva
authors.forename: Guobin
authors.initials: G
authors.lastname: Bao
authors.forename: Andre
authors.initials: A
authors.lastname: Zeug
authors.forename: Diethelm W
authors.initials: DW
authors.lastname: Richter
authors.forename: Erwin
authors.initials: E
authors.lastname: Neher
authors.forename: Evgeni
authors.initials: E
authors.lastname: Ponimaskin
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D019281:Dimerization; D031541:Fluorescence Resonance Energy Transfer; D054878:Lipoylation; D021962:Membrane Microdomains / Q000737:chemistry; D051379:Mice; D038761:Photobleaching; D011487:Protein Conformation; D044282:Receptor, Serotonin, 5-HT1A / Q000737:chemistry* / Q000378:metabolism; D058825:Serotonin 5-HT1 Receptor Agonists; D013050:Spectrometry, Fluorescence
chemical_list: D058825:Serotonin 5-HT1 Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A