title: The mouse GalR2 galanin receptor: genomic organization, cDNA cloning, and functional characterization.
abstract: The diverse physiological actions of galanin are thought to be mediated through activation of galanin receptors (GalRs). We report the genomic and cDNA cloning of a mouse GalR that possesses a genomic structure distinct from that of GalR1 and encodes a functional galanin receptor. The mouse GalR gene consists of two exons separated by a single intron within the protein-coding region. The splicing site for the intron is located at the junction between the third transmembrane domain and the second intracellular loop. The cDNA encodes a 370-amino acid putative G protein-coupled receptor that is markedly different from human GalR1 and rat GalR3 (38 and 57%) but shares high homology with rat GalR2 (94%). In binding studies utilizing membranes from COS-7 cells transfected with mouse GalR2 cDNA, the receptor displayed high affinity (K(D) = 0.47 nM) and saturable binding with 125I-galanin (Bmax = 670 fmol/mg). The radioligand binding can be displaced by galanin and its analogues in a rank order: galanin approximately = M40 approximately = M15 approximately = M35 approximately = C7 approximately = galanin(2-29) approximately = galanin(1-16) >> galanin(10-29) approximately = galanin(3-29), which resembles the pharmacological profile of the rat GalR2. Receptor activation by galanin in COS-7 cells stimulated phosphoinositide metabolism, which was not reversed by pertussis toxin. Thus, the galanin receptor encoded in the cloned mouse GalR gene is the type 2 galanin receptor and is active in both ligand binding and signaling assays.
authors.affiliation: Department of CNS/CV Biological Research, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
authors.forename: L
authors.initials: L
authors.lastname: Pang
authors.forename: T
authors.initials: T
authors.lastname: Hashemi
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Maguire
authors.forename: M P
authors.initials: MP
authors.lastname: Graziano
authors.forename: M
authors.initials: M
authors.lastname: Bayne
authors.forename: B
authors.initials: B
authors.lastname: Hawes
authors.forename: G
authors.initials: G
authors.lastname: Wong
authors.forename: S
authors.initials: S
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D016678:Genome; D006801:Humans; D007536:Isomerism; D051379:Mice; D008969:Molecular Sequence Data; D051381:Rats; D044092:Receptor, Galanin, Type 2; D044088:Receptors, Galanin; D018013:Receptors, Neuropeptide / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D044092:Receptor, Galanin, Type 2; D044088:Receptors, Galanin; D018013:Receptors, Neuropeptide