Conversion of the human 5-HT1D beta serotonin receptor to the rat 5-HT1B ligand-binding phenotype by Thr355Asn site directed mutagenesis

• Published in: Biochemical pharmacology Vol. 44; no. 10; p. 1917
• Main Authors: Metcalf, M A, McGuffin, R W, Hamblin, M W
• Format: Journal Article
• Language: English
• Published: England 17.11.1992
• Subjects: Amino Acid Sequence; Animals; Asparagine; Binding Sites; Cell Line - metabolism; Humans; Molecular Sequence Data; Mutagenesis, Site-Directed; Phenotype; Pindolol - analogs & derivatives; Pindolol - metabolism; Rats; Receptors, Serotonin - chemistry; Receptors, Serotonin - genetics; Receptors, Serotonin - metabolism; Recombinant Proteins - metabolism; Threonine
• ISSN: 0006-2952
• DOI: 10.1016/0006-2952(92)90092-W

The human 5-HT1D beta serotonin receptor and its rat homolog (also called the 5-HT1B receptor) share 93% amino acid identity, yet display markedly different pharmacological specificities. Comparison of deduced amino acid sequences among these and other recently cloned receptors suggested that this phenotypic difference might be attributable to a single human threonine355/rat asparagine351 amino acid difference in the putative seventh membrane spanning regions. We now report that Thr355Asn mutagenesis of the human 5-HT1D beta receptor alters the binding characteristics of the recombinant receptor in [3H]5-HT binding assays to a profile very similar to that of the rat 5-HT1B binding site. These results confirm that this single amino acid difference is responsible for the majority of the known pharmacological discrepancies between human and rat observed for 5-HT1D beta (5-HT1B) receptors.