Molecular cloning and expression of the human melanocyte stimulating hormone receptor cDNA

TLDR

Melanocytes and melanoma cells express receptors for melanocyte‑stimulating hormone. The authors isolated a 317‑amino‑acid cDNA clone (IID) from human melanoma cells that encodes a G‑protein‑coupled receptor–like protein; when expressed in COS‑7 cells it binds 125I‑NDP‑MSH specifically and is displaced by melanotropic peptides but not β‑endorphine, marking the first cloning of a melanotropin receptor gene.

Abstract

Melanocytes and melanoma cells are known to possess receptors for melanocyte stimulating hormone (MSH). A cDNA clone, designated IID, has been isolated from human melanoma cells and encodes a MSH receptor. The cloned cDNA encodes a 317 amino acid protein with transmembrane topography characteristics of a G‐protein‐coupled receptor, but it does not show striking similarity to already published sequences of other G‐protein‐coupled receptors. When IID cDNA is expressed in COS‐7 cells, it binds an 125 I‐labelled MSH analogue (NDP‐MSH) in a specific manner. The bound ligand could be displaced by melanotropic peptides, α‐MSH, β‐MSH, γ‐MSH and ACTH (adrenocorticotropic hormone), but not by the non‐melanotropic peptide, β‐endorphine. This is the first report of the cloning of a receptor gene of the melanotropin receptor family.