International Journal Of Bilogical Sciences
.: Home > International Journal Of Bilogical Sciences > 2015 > Volume 11 Number 4 > Fan Yang1,2, Hui Huang1, and Ya-Xiong Tao1
Biased Signaling in Naturally Occurring Mutations in Human Melanocortin-3 Receptor Gene
Fan Yang1,2, Hui Huang1, and Ya-Xiong Tao1
1. Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. 2. Current address: College of Life Sciences, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China. These authors contributed equally to this work. Corresponding author: Ya-Xiong Tao, PhD. Department of Anatomy, Physiology and Pharmacology, 212 Greene Hall, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States. Tel: 01-334-844-5396 FAX: 01-334-844-5388 Email: firstname.lastname@example.org.
The melanocortin-3 receptor (MC3R) is primarily expressed in the hypothalamus and plays an important role in the regulation of energy homeostasis. Recently, some studies demonstrated that MC3R also signals through mitogen-activated protein kinases (MAPKs), especially extracellular signal-regulated kinases 1 and 2 (ERK1/2). ERK1/2 signaling is known to alter gene expression, potentially contributing to the prolonged action of melanocortins on energy homeostasis regulation. In the present study, we performed detailed functional studies on 8 novel naturally occurring MC3R mutations recently reported, and the effects of endogenous MC3R agonist, α-melanocyte stimulating hormone (MSH), on ERK1/2 signaling on all 22 naturally occurring MC3R mutations reported to date. We found that mutants D158Y and L299V were potential pathogenic causes to obesity. Four residues, F82, D158, L249 and L299, played critical roles in different aspects of MC3R function. α-MSH exhibited balanced activity in Gs-cAMP and ERK1/2 signaling pathways in 15 of the 22 mutant MC3Rs. The other 7 mutant MC3Rs were biased to either one of the signaling pathways. In summary, we provided novel data about the structure-function relationship of MC3R, identifying residues important for receptor function. We also demonstrated that some mutations exhibited biased signaling, preferentially activating one intracellular signaling pathway, adding a new layer of complexity to MC3R pharmacology.
Melanocortin-3 receptor, naturally occurring mutations, cAMP signaling, ERK1/2 signaling, biased signaling
Date Deposited : 22 Feb 2016 10:07
Official URL: http://www.ijbs.com/v11i4
Last Modified : 22 Feb 2016 10:07
Volume 11, Number 4, - 2015 , ISSN 1449-2288
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