title: Two transmembrane Cys residues are involved in 5-HT4 receptor dimerization.
abstract: The 5-HT(4) receptor (5-HT(4)R) belongs to the G-protein-coupled receptor (GPCR) family and is of considerable interest for the development of new drugs to treat gastrointestinal diseases and memory disorders. The 5-HT(4)R exists as a constitutive dimer but its molecular determinants are still unknown. Using co-immunoprecipitation and Bioluminescence Resonance Energy Transfer (BRET) techniques, we show here that 5-HT(4)R homodimerization but not 5-HT(4)R-beta(2) adrenergic receptor (beta(2)AR) heterodimerization is largely decreased under reducing conditions suggesting the participation of disulfide bonds in 5-HT(4)R dimerization. Molecular modeling and protein docking experiments identified four cysteine (Cys) residues potentially involved in the dimer interface through intramolecular or intermolecular disulfide bonds. We show that disulfide bridges between Cys112 and Cys145 located within TM3 and TM4, respectively, are of critical importance for 5-HT(4)R dimer formation. Our data suggest that two disulfide bridges between two transmembrane Cys residues are involved in the dimerization interface of a GPCR.
authors: INSERM, U769, Châtenay-Malabry F-92296, France.
authors: Magali
authors: M
authors: Berthouze
authors: Lucie
authors: L
authors: Rivail
authors: Alexandre
authors: A
authors: Lucas
authors: Mohammed A
authors: MA
authors: Ayoub
authors: Olivier
authors: O
authors: Russo
authors: Sames
authors: S
authors: Sicsic
authors: Rodolphe
authors: R
authors: Fischmeister
authors: Isabelle
authors: I
authors: Berque-Bestel
authors: Ralf
authors: R
authors: Jockers
authors: Frank
authors: F
authors: Lezoualc'h
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D003545:Cysteine / Q000737:chemistry*; D019281:Dimerization; D004220:Disulfides / Q000737:chemistry; D004229:Dithiothreitol / Q000494:pharmacology; D006801:Humans; D047468:Immunoprecipitation; D008163:Luminescent Measurements; D017354:Point Mutation; D018343:Receptors, Adrenergic, beta-2 / Q000737:chemistry; D044422:Receptors, Serotonin, 5-HT4 / Q000737:chemistry* / Q000235:genetics
chemical_list: D004220:Disulfides; D018343:Receptors, Adrenergic, beta-2; D044422:Receptors, Serotonin, 5-HT4; D003545:Cysteine; D004229:Dithiothreitol