title: Glycosylation of beta(1)-adrenergic receptors regulates receptor surface expression and dimerization.
abstract: The beta(1)-adrenergic receptor (beta(1)AR) has one predicted site of N-linked glycosylation on its extracellular amino-terminus, but the glycosylation and potential functional importance of this site have not yet been examined. We show here that the beta(1)AR is glycosylated in various cell types and that mutation of the single predicted site of N-linked glycosylation (N15A) results in the formation of receptors that are not N-glycosylated. The beta(1)AR N15A mutant exhibited significantly decreased basal surface expression relative to the wild-type receptor but had no detectable deficits in ligand binding or agonist-promoted internalization. Co-immunoprecipitation experiments using Flag-tagged and HA-tagged receptors demonstrated that the beta(1)AR-N15A mutant receptor exhibits a markedly reduced capacity for dimerization relative to wild-type beta(1)AR. These data reveal that the beta(1)AR is glycosylated on Asn15 and that this glycosylation plays a role in regulating beta(1)AR surface expression and dimerization.
authors.affiliation: Department of Pharmacology, 5113 Rollins Research Center, Emory University School of Medicine, 1510 Clifton Rd., Atlanta, GA 30322, USA.
authors.forename: Junqi
authors.initials: J
authors.lastname: He
authors.forename: Jianguo
authors.initials: J
authors.lastname: Xu
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Castleberry
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Lau
authors.forename: Randy A
authors.initials: RA
authors.lastname: Hall
mesh_terms: D019943:Amino Acid Substitution; D001483:Base Sequence; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D017931:DNA Primers; D019281:Dimerization; D005786:Gene Expression Regulation; D006031:Glycosylation; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids; D016133:Polymerase Chain Reaction; D018342:Receptors, Adrenergic, beta-1 / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
chemical_list: D017931:DNA Primers; D018342:Receptors, Adrenergic, beta-1; D011994:Recombinant Proteins; D000242:Cyclic AMP; D007545:Isoproterenol