Primary structure and functional characterization of a human 5-HT1D-type serotonin receptor.
We describe the nucleic acid sequence encoding a human 5-hydroxytryptamine1D (5-HT1D) serotonin receptor and some of the functional characteristics of the gene product. The receptor gene was isolated by hybridization to a probe based on a canine thyroid cDNA (called RDC4) previously isolated by others and believed to encode a heretofore undetermined member of the guanine nucleotide-binding protein (G protein)-linked receptor family. The human clone we isolated, called MA6A, contains an apparently intronless open reading frame encoding a 377-amino acid polypeptide with the seven hydrophobic domains characteristic of G protein-linked receptors. The MA6A deduced amino acid sequence is 88% identical to that for RDC4 and 43% identical to that for the human 5-HT1A receptor. Expression of the human gene product in transfected cell lines results in the appearance of saturable high affinity 5-HT1D-type [3H]5-HT binding. The expressed receptor exhibits features indicative of coupling to Gi proteins, i.e., robust inhibition of forskolin-stimulated cAMP accumulation and formation of a pertussis toxin-sensitive high agonist affinity binding state. These findings may help clarify several ambiguities in the classification and action of serotonin receptor subtypes.
Hamblin
M W
MW
Geriatric Research, Education, and Clinical Center, Seattle Veterans Affairs Medical Center, Washington 98108.
Metcalf
M A
MA
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000032:analysis; D006801:Humans; D008969:Molecular Sequence Data; D037342:Pertussis Toxin; D011985:Receptors, Serotonin / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D011985:Receptors, Serotonin; D010566:Virulence Factors, Bordetella; D000242:Cyclic AMP; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins