A Setmelanotide-like Effect at MC4R Is Achieved by MC4R Dimer Separation

Biomolecules. 2022 Aug 15;12(8):1119. doi: 10.3390/biom12081119.


Melanocortin 4 receptor (MC4R) is part of the leptin-melanocortin pathway and plays an essential role in mediating energy homeostasis. Mutations in the MC4R are the most frequent monogenic cause for obesity. Due to increasing numbers of people with excess body weight, the MC4R has become a target of interest in the search of treatment options. We have previously reported that the MC4R forms homodimers, affecting receptor Gs signaling properties. Recent studies introducing setmelanotide, a novel synthetic MC4R agonist, suggest a predominant role of the Gq/11 pathway regarding weight regulation. In this study, we analyzed effects of inhibiting homodimerization on Gq/11 signaling using previously reported MC4R/CB1R chimeras. NanoBRETTM studies to determine protein-protein interaction were conducted, confirming decreased homodimerization capacities of chimeric receptors in HEK293 cells. Gq/11 signaling of chimeric receptors was analyzed using luciferase-based reporter gene (NFAT) assays. Results demonstrate an improvement of alpha-MSH-induced NFAT signaling of chimeras, reaching the level of setmelanotide signaling at wild-type MC4R (MC4R-WT). In summary, our study shows that inhibiting homodimerization has a setmelanotide-like effect on Gq/11 signaling, with chimeric receptors presenting increased potency compared to MC4R-WT. These findings indicate the potential of inhibiting MC4R homodimerization as a therapeutic target to treat obesity.

Keywords: GPCR; Gq/11; MC4R; homodimer; melanocortin 4 receptor; obesity; signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins
  • HEK293 Cells
  • Humans
  • Obesity / metabolism
  • Receptor, Melanocortin, Type 4* / genetics
  • Receptor, Melanocortin, Type 4* / metabolism
  • alpha-MSH* / analogs & derivatives
  • alpha-MSH* / metabolism
  • alpha-MSH* / pharmacology
  • alpha-MSH* / therapeutic use


  • Carrier Proteins
  • MC4R protein, human
  • Receptor, Melanocortin, Type 4
  • setmelanotide
  • alpha-MSH

Grant support

This research was funded by the Deutsche Forschungsgemeinschaft (DFG) (German Research Foundation) through SFB1423, project number 421152132, subproject B02 to H.B. and P.K. subprojects A01 and Z03 to P.S., and by project numbers 430971019 and 430970922 to P.K., as well as by the European Union’s Horizon 2020 MSCA Program under grant agreement 956314 (ALLODD) to P.S.