Melanocortin receptors and antagonists regulate pigmentation and body weight

✍ Scribed by Siobhán Jordan; Ian J. Jackson

• Book ID: 101303913
• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 52 KB
• Volume: 20
• Category: Article
• ISSN: 0265-9247
• DOI: 10.1002/(sici)1521-1878(199808)20:8<603::aid-bies1>3.0.co;2-j

✦ Synopsis

The action of two genetic loci-agouti and the melanocortin receptor-1 (Mc1r)have opposing effects in the control of mammalian pigmentation and ultimately determine the color of the pigment produced. In a recent paper, Ollmann et al. confirmed that the agouti protein acts via the Mc1r. They show that high-affinity binding of the agouti protein to Mc1r expressed in mammalian cells can be inhibited by the receptor's natural ligand, ␣-melanocyte-stimulating hormone (␣-MSH). In addition, genetic studies using mice carrying mutations at the Mc1r and agouti loci on a sensitized background of low tyrosinase expression confirm that a functional Mc1r is required for the maximum pigmentary effect of agouti. Thus, the Mc1r appears to be a unique, bifunctionally controlled receptor, activated by ␣-MSH and antagonized by agouti, both of which contribute to the variability seen in mammalian coat color.