Identification of GLP1R and MCHR1 signaling as novel GPCR targets of
MRAP2 protein
Abstract
The seven trans-membrane spanning G protein couple receptors(GPCRs)
constitute the largest family of FDA approved drug targets to treat
numerous human diseases, including metabolic associated disorders. The
Melanocortin Receptor Accessory Protein 2 (MRAP2), a small single
transmembrane protein broadly expressed in multiple tissues has been
defined as a vital endocrine pivot of five melanocortin
receptors(MC1R-MC5R) and several other GPCRs in the regulation of
central neuronal appetite and peripheral energy homeostasis. However,
MRAP2 null mouse model exhibited late onset obesity syndrome without
alteration on the eating behavior, a huge phenotypic departure from MC4R
KO animals. In this study, we identified GLP1R and MCHR1, the two energy
regulators as novel GPCR targets and characterized the specific regions
of MRAP2 protein that required for the pharmacological modulation of the
intracellular cAMP cascades. The simultaneous inhibitory effect of MRAP2
on the anorectic GLP1R and orectic MCHR1 signaling further elucidated
the complex endocrine network of GPCR signaling which may explain the
composite metabolic phenotypes of MRAP2 deficiency.