Expression cloning of a high-affinity melatonin receptor from Xenopus dermal melanophores.

AUTOR(ES)

Ebisawa, T

RESUMO

Using an expression cloning strategy, a high-affinity melatonin receptor cDNA has been isolated from Xenopus laevis dermal melanophores. Transient expression of the cDNA in COS-7 cells resulted in high-affinity 2-[125I]-iodomelatonin binding (Kd = 6.3 +/- 0.3 x 10(-11) M). In addition, six ligands exhibited a rank order of inhibition of specific 2-[125I]iodomelatonin binding that was identical to that reported for endogenous high-affinity receptors. Functional studies of CHO cells stably expressing the receptor cDNA showed that melatonin acting through the cloned receptor inhibited forskolin-stimulated cAMP accumulation in a dose-dependent manner. Northern blot analysis showed that melatonin receptor transcripts are moderately expressed in Xenopus dermal melanophores. The cDNA encodes a protein of 420 amino acids, which contains seven hydrophobic segments. Structural analysis revealed that the receptor protein is a newly discovered member of the guanine nucleotide binding protein-coupled receptor family.

Documentos Relacionados

• Molecular cloning of a high-affinity receptor for the growth factor-like lipid mediator lysophosphatidic acid from Xenopus oocytes
• Cloning, expression, and localization of a rat brain high-affinity glycine transporter.
• High-affinity neuropeptide Y receptor antagonists.
• Cloning and expression of the gene from Candida albicans that encodes a high-affinity corticosteroid-binding protein.
• Cloning of the outer membrane high-affinity Fe(III)-pyochelin receptor of Pseudomonas aeruginosa.