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Hoglin BE, Miner MV, Erbenebayar U, Shaughnessy CA, Dores RM. Trends in the evolution of the elasmobranch melanocortin-2 receptor: Insights from structure/function studies on the activation of whale shark Mc2r. Gen Comp Endocrinol 2023; 338:114278. [PMID: 36996927 DOI: 10.1016/j.ygcen.2023.114278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/27/2023] [Accepted: 03/25/2023] [Indexed: 03/30/2023]
Abstract
To understand the mechanism for activation of the melanocortin-2 receptor (Mc2r) of the elasmobranch, Rhincodon typus (whale shark; ws), wsmc2r was co-expressed with wsmrap1 in CHO cells, and the transfected cells were stimulated with alanine-substituted analogs of ACTH(1-24) at the "message" motif (H6F7R8W9) and the "address" motif (K15K16R17R18P19). Complete alanine substitution of the H6F7R8W9 motif blocked activation, whereas single alanine substitution at this motif indicated the following hierarchy of position importance for activation: W9 > R8, and substitution at F7 and H6 had no effect on activation. The same analysis was done on a representative bony vertebrate Mc2r ortholog (Amia calva; bowfin; bf) and the order of position importance for activation was W9 > R8 = F7, (alanine substitution at H6 was negligible). Complete alanine substitution at the K15K16R17R18P19 motif resulted in distinct outcomes for wsMc2r and bfMc2r. For bfMc2r, this analog blocked activation-an outcome typical for bony vertebrate Mc2r orthologs. For wsMc2r, this analog resulted in a shift in sensitivity to stimulation of the analog as compared to ACTH(1-24) by two orders of magnitude, but the dose response curve did reach saturation. To evaluate whether the EC2 domain of wsMc2r plays a role in activation, a chimeric wsMc2r was made in which the EC2 domain was replaced with the EC2 domain from a melanocortin receptor that does not interact with Mrap1 (i.e., Xenopus tropicalis Mc1r). This substitution did not negatively impact the activation of the chimeric receptor. In addition, alanine substitution at a putative activation motif in the N-terminal of wsMrap1 did not affect the sensitivity of wsMc2r to stimulation by ACTH(1-24). Collectively, these observations suggest that wsMc2r may only have a HFRW binding site for melanocortin-related ligand which would explain how wsMc2r could be activated by either ACTH or MSH-sized ligands.
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Affiliation(s)
- Brianne E Hoglin
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Marin V Miner
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Ugumuur Erbenebayar
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | | | - Robert M Dores
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA.
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Melanocortin-5 Receptor: Pharmacology and Its Regulation of Energy Metabolism. Int J Mol Sci 2022; 23:ijms23158727. [PMID: 35955857 PMCID: PMC9369360 DOI: 10.3390/ijms23158727] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 12/12/2022] Open
Abstract
As the most recent melanocortin receptor (MCR) identified, melanocortin-5 receptor (MC5R) has unique tissue expression patterns, pharmacological properties, and physiological functions. Different from the other four MCR subtypes, MC5R is widely distributed in both the central nervous system and peripheral tissues and is associated with multiple functions. MC5R in sebaceous and preputial glands regulates lipid production and sexual behavior, respectively. MC5R expressed in immune cells is involved in immunomodulation. Among the five MCRs, MC5R is the predominant subtype expressed in skeletal muscle and white adipose tissue, tissues critical for energy metabolism. Activated MC5R triggers lipid mobilization in adipocytes and glucose uptake in skeletal muscle. Therefore, MC5R is a potential target for treating patients with obesity and diabetes mellitus. Melanocortin-2 receptor accessory proteins can modulate the cell surface expression, dimerization, and pharmacology of MC5R. This minireview summarizes the molecular and pharmacological properties of MC5R and highlights the progress made on MC5R in energy metabolism. We poInt. out knowledge gaps that need to be explored in the future.
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Arab-Bafrani Z, Zabihi E, Hoseini SM, Sepehri H, Khalili M. Silver nanoparticles modify hypothalamic-pituitary-interrenal axis and block cortisol response to an acute stress in zebrafish, Danio rerio. Toxicol Ind Health 2022; 38:201-209. [PMID: 35343814 DOI: 10.1177/07482337221086128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study aimed at assessing the effects of exposure to silver nanoparticle (AgNP) and a subsequent acute stress on the expression of various genes involved in the hypothalamus-pituitary-interrenal (HPI) axis in zebrafish, Danio rerio. The fish were exposed to 0 (Control), 0.1 (LC), 0.4 (MC), and 1.2 (HC) mg Ag/L (as AgNP) over a 2-week period, followed by an acute air exposure stress. The whole body cortisol and the expression of selected genes in the fish brain and kidney were analyzed, before and after the acute stress. The results showed that AgNP increased basal cortisol levels and the expression of corticotropin releasing factor, prohormone convertase 1, pro-opiomelanocortin, and melanocortin 2 receptor; however, it suppressed/inhibited whole body cortisol, brain corticotropin releasing factor responses, pro-opiomelanocortin, and the kidney melanocortin 2 receptor responses to the acute stress. AgNP down-regulated the expression of the steroidogenic acute regulatory protein, but it intensified the gene expression in response to the acute stress. Before the acute stress, LC treatment exhibited an up-regulation in Cytochrome P450-11A-1 expression, but MC and HC treatments induced down-regulation. After the acute stress, the AgNP-exposed fish exhibited decreased Cytochrome P450-11A-1 expressions, compared with the Control. Exposure to AgNP significantly increased Cytochrome P450-11B expression. However, after the acute stress, LC treatment exhibited an up-regulation, but MC and HC treatments exhibited down-regulation in the Cytochrome P450-11B gene expression. In conclusion, AgNP suppressed cortisol response to stress, which appears to be a consequence of alterations in the HPI axis at the transcriptomic levels.
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Affiliation(s)
- Zahra Arab-Bafrani
- Metabolic Disorders Research Center, 125691Golestan University of Medical Sciences, Gorgan, Iran.,Department of Biochemistry and Biophysics, Faculty of Medicine, 125691Golestan University of Medical Sciences, Gorgan, Iran
| | - Erfan Zabihi
- Metabolic Disorders Research Center, 125691Golestan University of Medical Sciences, Gorgan, Iran.,Department of Polymer Engineering, Faculty of Engineering, Golestan University, Gorgan, Iran
| | - Seyyed Morteza Hoseini
- Inland Waters Aquatics Resources Research Center, 163003Iranian Fisheries Sciences Research Institute, Agricultural Research, Education and Extension Organization, Gorgan, Iran
| | - Hamid Sepehri
- Department of Physiology, Faculty of Medicine, 125691Golestan University of Medical Sciences, Gorgan, Iran
| | - Mohsen Khalili
- Stem Cell Research Center, 125691Golestan University of Medical Sciences, Gorgan, Iran.,Medical Cellular and Molecular Research Center, 125691Golestan University of Medical Sciences, Gorgan, Iran
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Translational advances of melanocortin drugs: Integrating biology, chemistry and genetics. Semin Immunol 2022; 59:101603. [PMID: 35341670 DOI: 10.1016/j.smim.2022.101603] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 01/15/2023]
Abstract
Melanocortin receptors have emerged as important targets with a very unusual versatility, as their widespread distribution on multiple tissues (e.g. skin, adrenal glands, brain, immune cells, exocrine glands) together with the variety of physiological processes they control (pigmentation, cortisol release, satiety mechanism, inflammation, secretions), place this family of receptors as genuine therapeutic targets for many disorders. This review focuses in the journey of the development of melanocortin receptors as therapeutic targets from the discovery of their existence in the early 1990 s to the approval of the first few drugs of this class. Two major areas of development characterise the current state of melanocortin drug development: their role in obesity, recently culminated with the approval of setmelanotide, and their potential for the treatment of chronic inflammatory and autoimmune diseases like rheumatoid arthritis, multiple sclerosis or fibrosis. The pro-resolving nature of these drugs offers the advantage of acting by mimicking the way our body naturally resolves inflammation, expecting fewer side effects and a more balanced (i.e. non-immunosuppressive) response from them. Here we also review the approaches followed for the design and development of novel compounds, the importance of the GPCR nature of these receptors in the process of drug development, therapeutic value, current challenges and successes, and the potential for the implementation of precision medicine approaches through the incorporation of genetics advances.
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Davis PE, Wilkinson EC, Dores RM. Identifying Common Features in the Activation of Melanocortin-2 Receptors: Studies on the Xenopus tropicalis Melanocortin-2 Receptor. Int J Mol Sci 2019; 20:ijms20174166. [PMID: 31454910 PMCID: PMC6747542 DOI: 10.3390/ijms20174166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 08/21/2019] [Accepted: 08/24/2019] [Indexed: 12/03/2022] Open
Abstract
The interaction between the pituitary hormone, adrenocorticotropin (ACTH), and melanocortin-2 receptor (MC2R) orthologs involves the H6 F7 R8 W9 and R/K15 K16 R17 R18 motifs in ACTH making contact with corresponding contact sites on MC2R. Earlier studies have localized the common HFRW binding site of all melanocortin receptors to residues in TM2, TM3, and TM6 that are located close to the extracellular space. The current study has identified residues in Xenopus tropicalis (xt) MC2R in TM4 (I158, F161), in EC2 (M166), and in TM5 (V172) that also are involved in activation of xtMC2R, and may be in the R/KKRR contact site of xtMC2R. These results are compared to earlier studies on the corresponding domains of human MC2R and rainbow trout MC2R in an effort to identify common features in the activation of teleost and tetrapod MC2R orthologs following stimulation with ACTH.
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Affiliation(s)
- Perry E Davis
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Emily C Wilkinson
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA.
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Zhu M, Xu B, Wang M, Liu S, Zhang Y, Zhang C. Pharmacological modulation of MRAP2 protein on melanocortin receptors in the sea lamprey. Endocr Connect 2019; 8:378-388. [PMID: 30856611 PMCID: PMC6454295 DOI: 10.1530/ec-19-0019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/11/2019] [Indexed: 12/28/2022]
Abstract
Melanocortin receptors (MCRs) and their accessory proteins (MRAPs) evolutionarily first appear in the genome of sea lamprey. The most ancient melanocortin system consists of only two melanocortin receptors (slMCa and slMCb) and one MRAP2 (slMRAP2) protein, but the physiological roles have not been fully explored in this primitive species. Here, we synthesize and characterize the pharmacological features of slMRAP2 protein on two slMCRs. Our results show that the slMRAP2 protein lacks the long carboxyl terminus; it directly interacts and decreases the surface expression but enhances the α-MSH-induced agonism of slMCa and slMCb. In comparison with higher organisms such as elephant shark and zebrafish, we also demonstrate the constantly evolving regulatory function of the carboxyl terminus of MRAP2 protein, the unique antiparallel topology of slMRAP2 dimer and the homo- and hetero-dimerization of two slMCRs. This study elucidates the presence and modulation of melanocortin receptor by the accessory protein of the agnathans for the first time, which provides a better insight of the melanocortin system in ancient species of chordates.
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Affiliation(s)
- Ming Zhu
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Bingxin Xu
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Meng Wang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Shangyun Liu
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yue Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chao Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
- Correspondence should be addressed to C Zhang:
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Liao S, Dong J, Xu W, Xi B, Tao Y, Liu B, Xie J. Molecular cloning, tissue distribution, and pharmacological characterization of blunt snout bream (Megalobrama amblycephala) melanocortin-5 receptor. FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:311-321. [PMID: 30288633 DOI: 10.1007/s10695-018-0563-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
The melanocortin-5 receptor (MC5R) plays an important role in the regulation of exocrine secretion in mammals. Its function in fish is not well established. In this study, we reported the molecular cloning, tissue expression, and pharmacological characterization of Megalobrama amblycephala MC5R (MamMC5R), as well as the effect of catching stress on its expression. The full-length cDNA of Mammc5r gene was 1237 bp, consisted of a 990-bp open reading frame encoding 329 amino acids. Sequence analyses revealed that the nucleotide and amino acid sequences of Mammc5r were highly homologous (> 90%) with MC5Rs of zebrafish, common carp, and goldfish. Tissue expression profile analysis showed that Mammc5r was widely expressed in both central and peripheral tissues, with the highest expression in the brain. Catching stress significantly changed the expression of Mammc5r in the skin, brain, and eye. In the skin, the expression level of Mammc5r was significantly reduced at 1 h and 4 h and increased at 24 h after catching stress. The Mammc5r expression level was rapidly upregulated in the brain and eye at 1 h and then decreased to the level before stress at 4 h and 24 h. With human MC5R (HsaMC5R) as a control, several agonists including α-melanocyte-stimulating hormone (α-MSH), and β-MSH in addition to an analogue [Nle4, D-Phe7]-α-MSH (NDP-MSH), were used to investigate the binding and signaling properties of MamMC5R. The results revealed that MamMC5R had the highest affinity for NDP-MSH, followed by α- and β-MSH. Taken together, the data suggested that MamMC5R might play a role in stress response in M. amblycephala.
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Affiliation(s)
- Shengchen Liao
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Jingjing Dong
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Weina Xu
- Key Laboratory of Aquatic Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Bingwen Xi
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China.
| | - Yaxiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849, USA.
| | - Bo Liu
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Jun Xie
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China.
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Springer MS, Gatesy J. Evolution of the MC5R gene in placental mammals with evidence for its inactivation in multiple lineages that lack sebaceous glands. Mol Phylogenet Evol 2017; 120:364-374. [PMID: 29277542 DOI: 10.1016/j.ympev.2017.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/09/2017] [Indexed: 12/30/2022]
Abstract
MC5R is one of five melanocortin receptor genes found in placental mammals. MC5R plays an important role in energy homeostasis and is also expressed in the terminal differentiation of sebaceous glands. Among placental mammals there are multiple lineages that either lack or have degenerative sebaceous glands including Cetacea (whales, dolphins, and porpoises), Hippopotamidae (hippopotamuses), Sirenia (manatees and dugongs), Proboscidea (elephants), Rhinocerotidae (rhinos), and Heterocephalus glaber (naked mole rat). Given the loss or diminution of sebaceous glands in these taxa, we procured MC5R sequences from publicly available genomes and transcriptomes, supplemented by a newly generated sequence for Choeropsis liberiensis (pygmy hippopotamus), to determine if this gene remains intact or is inactivated in association with loss/reduction of sebaceous glands. Our data set includes complete MC5R sequences for 114 placental mammal species including two individuals of Mammuthus primigenius (woolly mammoth) from Oimyakon and Wrangel Island. Complete loss or inactivation of the MC5R gene occurs in multiple placental lineages that have lost sebaceous glands (Cetacea, West Indian manatee, African elephant, white rhinoceros) or are characterized by unusual skin (pangolins, aardvarks). Both M. primigenius individuals share inactivating mutations with the African elephant even though sebaceous glands have been reported in the former. MC5R remains intact in hippopotamuses and the naked mole rat, although slightly elevated dN/dS ratios in these lineages allow for the possibility that the accumulation of inactivating mutations in MC5R may lag behind the relaxation of purifying selection. For Cetacea and Hippopotamidae, the absence of shared inactivating mutations in two different skin genes (MC5R, PSORS1C2) is consistent with the hypothesis that semi-aquatic lifestyles were acquired independently in these clades following divergence from a common ancestor.
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Affiliation(s)
- Mark S Springer
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA.
| | - John Gatesy
- Division of Vertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA.
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Dib L, San-Jose LM, Ducrest AL, Salamin N, Roulin A. Selection on the Major Color Gene Melanocortin-1-Receptor Shaped the Evolution of the Melanocortin System Genes. Int J Mol Sci 2017; 18:ijms18122618. [PMID: 29206201 PMCID: PMC5751221 DOI: 10.3390/ijms18122618] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/28/2017] [Accepted: 11/29/2017] [Indexed: 12/20/2022] Open
Abstract
Modular genetic systems and networks have complex evolutionary histories shaped by selection acting on single genes as well as on their integrated function within the network. However, uncovering molecular coevolution requires the detection of coevolving sites in sequences. Detailed knowledge of the functions of each gene in the system is also necessary to identify the selective agents driving coevolution. Using recently developed computational tools, we investigated the effect of positive selection on the coevolution of ten major genes in the melanocortin system, responsible for multiple physiological functions and human diseases. Substitutions driven by positive selection at the melanocortin-1-receptor (MC1R) induced more coevolutionary changes on the system than positive selection on other genes in the system. Contrarily, selection on the highly pleiotropic POMC gene, which orchestrates the activation of the different melanocortin receptors, had the lowest coevolutionary influence. MC1R and possibly its main function, melanin pigmentation, seems to have influenced the evolution of the melanocortin system more than functions regulated by MC2-5Rs such as energy homeostasis, glucocorticoid-dependent stress and anti-inflammatory responses. Although replication in other regulatory systems is needed, this suggests that single functional aspects of a genetic network or system can be of higher importance than others in shaping coevolution among the genes that integrate it.
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Affiliation(s)
- Linda Dib
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne, Switzerland.
- Laboratoire de Recherche en Neuroimagerie, Centre Hospitalier Universitaire Vaudois, 1015 Lausanne, Switzerland.
| | - Luis M San-Jose
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Anne-Lyse Ducrest
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Nicolas Salamin
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Quartier Sorge, 1015 Lausanne, Switzerland.
- Department of Computational Biology, University of Lausanne, Rue du Bugnon 27, 1011 Lausanne, Switzerland.
| | - Alexandre Roulin
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne, Switzerland.
- Department of Computational Biology, University of Lausanne, Rue du Bugnon 27, 1011 Lausanne, Switzerland.
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Dores RM, Liang L, Davis P, Thomas AL, Petko B. 60 YEARS OF POMC: Melanocortin receptors: evolution of ligand selectivity for melanocortin peptides. J Mol Endocrinol 2016; 56:T119-33. [PMID: 26792827 DOI: 10.1530/jme-15-0292] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 01/31/2023]
Abstract
The evolution of the melanocortin receptors (MCRs) is linked to the evolution of adrenocorticotrophic hormone (ACTH), the melanocyte-stimulating hormones (MSHs), and their common precursor pro-opiomelanocortin (POMC). The origin of the MCRs and POMC appears to be grounded in the early radiation of the ancestral protochordates. During the genome duplications that have occurred during the evolution of the chordates, the organization plan for POMC was established, and features that have been retained include, the high conservation of the amino acid sequences of α-MSH and ACTH, and the presence of the HFRW MCR activation motif in all of the melanocortin peptides (i.e. ACTH, α-MSH, β-MSH, γ-MSH, and δ-MSH). For the MCRs, the chordate genome duplication events resulted in the proliferation of paralogous receptor genes, and a divergence in ligand selectivity. While most gnathostome MCRs can be activated by either ACTH or the MSHs, teleost and tetrapod MC2R orthologs can only be activated by ACTH. The appearance of the accessory protein, MRAP1, paralleled the emergence of teleost and tetrapods MC2R ligand selectivity, and the dependence of these orthologs on MRAP1 for trafficking to the plasma membrane. The accessory protein, MRAP2, does not affect MC2R ligand selectivity, but does influence the functionality of MC4R orthologs. In this regard, the roles that these accessory proteins may play in the physiology of the five MCRs (i.e. MC1R, MC2R, MC3R, MC4R, and MC5R) are discussed.
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Affiliation(s)
- Robert M Dores
- Department of Biological SciencesUniversity of Denver, Denver, Colorado, USA
| | - Liang Liang
- Department of Biological SciencesUniversity of Denver, Denver, Colorado, USA
| | - Perry Davis
- Department of Biological SciencesUniversity of Denver, Denver, Colorado, USA
| | - Alexa L Thomas
- Department of Biological SciencesUniversity of Denver, Denver, Colorado, USA
| | - Bogdana Petko
- Department of Biological SciencesUniversity of Denver, Denver, Colorado, USA
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Dores RM. Hypothesis and Theory: Revisiting Views on the Co-evolution of the Melanocortin Receptors and the Accessory Proteins, MRAP1 and MRAP2. Front Endocrinol (Lausanne) 2016; 7:79. [PMID: 27445982 PMCID: PMC4923161 DOI: 10.3389/fendo.2016.00079] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/17/2016] [Indexed: 01/09/2023] Open
Abstract
The evolution of the melanocortin receptors (MCRs) is closely associated with the evolution of the melanocortin-2 receptor accessory proteins (MRAPs). Recent annotation of the elephant shark genome project revealed the sequence of a putative MRAP1 ortholog. The presence of this sequence in the genome of a cartilaginous fish raises the possibility that the mrap1 and mrap2 genes in the genomes of gnathostome vertebrates were the result of the chordate 2R genome duplication event. The presence of a putative MRAP1 ortholog in a cartilaginous fish genome is perplexing. Recent studies on melanocortin-2 receptor (MC2R) in the genomes of the elephant shark and the Japanese stingray indicate that these MC2R orthologs can be functionally expressed in CHO cells without co-expression of an exogenous mrap1 cDNA. The novel ligand selectivity of these cartilaginous fish MC2R orthologs is discussed. Finally, the origin of the mc2r and mc5r genes is reevaluated. The distinctive primary sequence conservation of MC2R and MC5R is discussed in light of the physiological roles of these two MCR paralogs.
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Affiliation(s)
- Robert M. Dores
- Department of Biological Sciences, University of Denver, Denver, CO, USA
- *Correspondence: Robert M. Dores,
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Cortés R, Navarro S, Agulleiro MJ, Guillot R, García-Herranz V, Sánchez E, Cerdá-Reverter JM. Evolution of the melanocortin system. Gen Comp Endocrinol 2014; 209:3-10. [PMID: 24768673 DOI: 10.1016/j.ygcen.2014.04.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 04/01/2014] [Accepted: 04/03/2014] [Indexed: 11/17/2022]
Abstract
The melanocortin system is one of the most complex of the hormonal systems. It involves different agonists encoded in the multiplex precursor proopiomelanocortin (POMC) or in different genes as β-defensins, endogenous antagonist, like agouti-signalling protein (ASIP) or agouti-related protein (AGRP), and five different melanocortin receptors (MCRs). Rounds of whole genome duplication events have preceded the functional and molecular diversification of the family in addition some co-evolutionary and tandem duplication processes have been proposed. The evolutionary patterns of the different partners are controversial and different hypotheses have emerged from a study of the sequenced genomes. In this review, we summarize the different evolutionary hypotheses proposed for the different melanocortin partners.
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Affiliation(s)
- Raúl Cortés
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Sandra Navarro
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Maria Josep Agulleiro
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Raúl Guillot
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Víctor García-Herranz
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - Elisa Sánchez
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain
| | - José Miguel Cerdá-Reverter
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes, Castellón, Spain.
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13
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Barlock TK, Gehr DT, Dores RM. Analysis of the pharmacological properties of chicken melanocortin-2 receptor (cMC2R) and chicken melanocortin-2 accessory protein 1 (cMRAP1). Gen Comp Endocrinol 2014; 205:260-7. [PMID: 24726989 DOI: 10.1016/j.ygcen.2014.03.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 03/23/2014] [Accepted: 03/25/2014] [Indexed: 01/02/2023]
Abstract
The chicken (Gallus gallus) melanocortin-2 receptor (cMC2R) can be functionally expressed in CHO cells when chicken melanocortin-2 receptor accessory protein 1 (cMRAP1) is co-expressed. The transiently transfected CHO cells responded in a robust manner to stimulation by hACTH(1-24) (EC50 value=2.7 × 10(-12)M +/- 1.3 × 10(-12)), but the transfected CHO cells could not be stimulated by NDP-MSH at concentrations as high as 10(-7)M. Incubation of cMC2R/cMRAP1 transfected cells with alanine substituted analogs of hACTH(1-24) at amino acid positions F(7) or W(9) completely blocked stimulation of the transfected cells. Similarly, incubation of cMC2R/cMRAP1 transfected cells with an analog of hACTH(1-24) with alanine substitutions at amino acid positions R(17)R(18)P(19) resulted in a 276 fold shift in EC50 value relative to the positive control (p<0.004). Collectively these observations suggest that cMC2R has binding sites for the HFRW motif and KKRRP motif of hACTH(1-24), and both motifs are required for full activation of the receptor. While previous studies had shown that Anolis carolinensis MC2R and Xenopus tropicalis MC2R could be functionally expressed in CHO cells that co-expressed mouse MRAP1, co-expression of these non-mammalian tetrapod MC2Rs with cMRAP1 resulted in a significant increase in sensitivity to hACTH(1-24), as measured by EC50 value, for A. carolinensis MC2R (p<0.005) and X. tropicalis MC2R (p<0.007). The implications of these observations are discussed.
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Affiliation(s)
- Travis K Barlock
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Deshae T Gehr
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Robert M Dores
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA.
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14
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Dores RM, Liang L. Analyzing the activation of the melanocortin-2 receptor of tetrapods. Gen Comp Endocrinol 2014; 203:3-9. [PMID: 24713445 DOI: 10.1016/j.ygcen.2014.03.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 01/17/2023]
Abstract
Following the biochemical characterization of the pituitary hormone, adrenocorticotropin (ACTH), in the 1950's, a number of structure/function studies were done which identifies two amino acid motifs in ACTH, the HFRW motif and KKRR motif, as critical for the activation of the "ACTH" receptor on adrenal cortex cells. In the 1990's the "ACTH" receptor was identified as a member of the melanocortin receptor gene family, and given the name melanocortin-2 receptor (MC2R). Since that time a number of studies on both tetrapod and teleost MC2R orthologs have established that these orthologs can only be activated by ACTH, but not by any of the MSH-sized melanocortin ligands, and these orthologs require interaction with the melanocortin-2 receptor accessory protein (MRAP) for functional expression. This review summarizes recent structure/function studies on human ACTH, and points out the importance of the GKPVG motif in ACTH for the activation of the receptor. In this regard, a multiple-step model for the activation of tetrapod and teleost MC2R orthologs is presented, and the evolution of gnathostome MC2R ligand selectivity and the requirement for MRAP interaction is discussed in light of a recent study on a cartilaginous fish MC2R ortholog. This review contains excerpts from the Gorbman/Bern Lecture presented at the Second Meeting of the North American Society for Comparative Endocrinology (NASCE).
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Affiliation(s)
- Robert M Dores
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA.
| | - Liang Liang
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
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15
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Dores RM, Londraville RL, Prokop J, Davis P, Dewey N, Lesinski N. Molecular evolution of GPCRs: Melanocortin/melanocortin receptors. J Mol Endocrinol 2014; 52:T29-42. [PMID: 24868105 DOI: 10.1530/jme-14-0050] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The melanocortin receptors (MCRs) are a family of G protein-coupled receptors that are activated by melanocortin ligands derived from the proprotein, proopiomelanocortin (POMC). During the radiation of the gnathostomes, the five receptors have become functionally segregated (i.e. melanocortin 1 receptor (MC1R), pigmentation regulation; MC2R, glucocorticoid synthesis; MC3R and MC4R, energy homeostasis; and MC5R, exocrine gland physiology). A focus of this review is the role that ligand selectivity plays in the hypothalamus/pituitary/adrenal-interrenal (HPA-I) axis of teleosts and tetrapods as a result of the exclusive ligand selectivity of MC2R for the ligand ACTH. A second focal point of this review is the roles that the accessory proteins melanocortin 2 receptor accessory protein 1 (MRAP1) and MRAP2 are playing in, respectively, the HPA-I axis (MC2R) and the regulation of energy homeostasis by neurons in the hypothalamus (MC4R) of teleosts and tetrapods. In addition, observations are presented on trends in the ligand selectivity parameters of cartilaginous fish, teleost, and tetrapod MC1R, MC3R, MC4R, and MC5R paralogs, and the modeling of the HFRW motif of ACTH(1-24) when compared with α-MSH. The radiation of the MCRs during the evolution of the gnathostomes provides examples of how the physiology of endocrine and neuronal circuits can be shaped by ligand selectivity, the intersession of reverse agonists (agouti-related peptides (AGRPs)), and interactions with accessory proteins (MRAPs).
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Affiliation(s)
- Robert M Dores
- Department of Biological SciencesUniversity of Denver, Denver, Colorado 80210, USADepartment of BiologyUniversity of Akron, Akron, Ohio 44325, USA
| | - Richard L Londraville
- Department of Biological SciencesUniversity of Denver, Denver, Colorado 80210, USADepartment of BiologyUniversity of Akron, Akron, Ohio 44325, USA
| | - Jeremy Prokop
- Department of Biological SciencesUniversity of Denver, Denver, Colorado 80210, USADepartment of BiologyUniversity of Akron, Akron, Ohio 44325, USA
| | - Perry Davis
- Department of Biological SciencesUniversity of Denver, Denver, Colorado 80210, USADepartment of BiologyUniversity of Akron, Akron, Ohio 44325, USA
| | - Nathan Dewey
- Department of Biological SciencesUniversity of Denver, Denver, Colorado 80210, USADepartment of BiologyUniversity of Akron, Akron, Ohio 44325, USA
| | - Natalie Lesinski
- Department of Biological SciencesUniversity of Denver, Denver, Colorado 80210, USADepartment of BiologyUniversity of Akron, Akron, Ohio 44325, USA
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16
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Dores RM. Observations on the evolution of the melanocortin receptor gene family: distinctive features of the melanocortin-2 receptor. Front Neurosci 2013; 7:28. [PMID: 23596380 PMCID: PMC3622036 DOI: 10.3389/fnins.2013.00028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 02/19/2013] [Indexed: 01/03/2023] Open
Abstract
The melanocortin receptors (MCRs) are a gene family in the rhodopsin class of G protein-coupled receptors. Based on the analysis of several metazoan genome databases it appears that the MCRs are only found in chordates. The presence of five genes in the family (i.e., mc1r, mc2r, mc3r, mc4r, mc5r) in representatives of the tetrapods indicates that the gene family is the result of two genome duplication events and one local gene duplication event during the evolution of the chordates. The MCRs are activated by melanocortin ligands (i.e., ACTH, α-MSH, β-MSH, γ-MSH, δ-MSH) which are all derived from the polypeptide hormone/neuropeptide precursor, POMC, and as a result the functional evolution of the MCRs is intimately associated with the co-evolution of POMC endocrine and neuronal circuits. This review will consider the origin of the MCRs, and discuss the evolutionary relationship between MC2R, MC5R, and MC4R. In addition, this review will analyze the functional evolution of the mc2r gene in light of the co-evolution of the MRAP (Melanocortin-2 Receptor Accessory Protein) gene family.
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Affiliation(s)
- Robert M Dores
- Department of Biological Sciences, University of Denver Denver, CO, USA
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17
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Liang L, Reinick C, Angleson JK, Dores RM. Evolution of melanocortin receptors in cartilaginous fish: melanocortin receptors and the stress axis in elasmobranches. Gen Comp Endocrinol 2013; 181:4-9. [PMID: 22964529 DOI: 10.1016/j.ygcen.2012.08.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 08/05/2012] [Accepted: 08/12/2012] [Indexed: 11/17/2022]
Abstract
There is general agreement that the presence of five melanocortin receptor genes in tetrapods is the result of two genome duplications that occurred prior to the emergence of the gnathostomes, and at least one local gene duplication that occurred early in the radiation of the ancestral gnathostomes. Hence, it is assumed that representatives from the extant classes of gnathostomes (i.e., Chondrichthyes, Actinopterygii, Sarcopterygii) should also have five paralogous melanocortin genes. Current studies on cartilaginous fishes indicate that while there is evidence for five paralogous melanocortin receptor genes in this class, to date all five paralogs have not been detected in the genome of a single species. This mini-review will discuss the ligand selectivity properties of the melanocortin-3 receptor of the elephant shark (subclass Holocephali) and the ligand selectivity properties of the melanocortin-3 receptor, melanocortin-4 receptor, and the melanocortin-5 receptor of the dogfish (subclass Elasmobranchii). The potential relationship of these melanocortin receptors to the hypothalamus/pituitary/interrenal axis will be discussed.
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Affiliation(s)
- Liang Liang
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
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Reinick CL, Liang L, Angleson JK, Dores RM. Identification of an MRAP-independent melanocortin-2 receptor: functional expression of the cartilaginous fish, Callorhinchus milii, melanocortin-2 receptor in CHO cells. Endocrinology 2012; 153:4757-65. [PMID: 22919056 PMCID: PMC3512025 DOI: 10.1210/en.2012-1482] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Phylogenetic analyses indicate that the genome of the cartilaginous fish, Callorhynchus milii (elephant shark), encodes a melanocortin-2 receptor (MC2R) ortholog. Expression of the elephant shark mc2r cDNA in Chinese hamster ovary (CHO) cells revealed that trafficking to the plasma membrane and functional activation of the receptor do not require coexpression with an exogenous melanocortin receptor-2 accessory protein (mrap) cDNA. Ligand selectivity studies indicated that elephant shark MC2R-transfected CHO cells produced cAMP in a dose-dependent manner when stimulated with either human ACTH (1-24) or [Nle(4), d-Phe(7)]-MSH. Furthermore, the order of ligand selectivity when elephant shark MC2R-transfected CHO cells were stimulated with cartilaginous fish melanocortins was as follows: ACTH (1-25) = γ-MSH = δ-MSH > αMSH = β-MSH. Elephant shark MC2R is the first vertebrate MC2R ortholog to be analyzed that does not require melanocortin receptor-2 accessory protein 1 for functional activation. In addition, elephant MC2R is currently the only MC2R ortholog that can be activated by either ACTH- or MSH-sized ligands. Hence, it would appear that MC2R dependence on melanocortin receptor-2 accessory protein 1 for functional activation and the exclusive selectivity of this melanocortin receptor for ACTH are features that emerged after the divergence of the ancestral cartilaginous fishes and the ancestral bony fishes more than 400 million years ago.
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Affiliation(s)
- Christina L Reinick
- Department of Biological Sciences, University of Denver, Denver, Colorado 80210, USA
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19
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Reinick CL, Liang L, Angleson JK, Dores RM. Functional expression of Squalus acanthias melanocortin-5 receptor in CHO cells: ligand selectivity and interaction with MRAP. Eur J Pharmacol 2012; 680:1-7. [PMID: 22314217 DOI: 10.1016/j.ejphar.2012.01.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 01/18/2012] [Accepted: 01/21/2012] [Indexed: 12/26/2022]
Abstract
The melanocortin-5 receptor (MC(5)) of the dogfish Squalus acanthias (SacMC(5) receptor) can be functionally expressed in CHO cells in the absence of the co-expression of an exogenous MRAP cDNA. Both human ACTH(1-24) and dogfish ACTH(1-25) were much better stimulators of the SacMC(5) receptor than any of the mammalian or dogfish MSH ligands that were tested. The order of ligand selectivity for the dogfish melanocortins was ACTH(1-25)>αMSH>γ-MSH=δ-MSH>β-MSH. Unlike mammalian MC(5) receptors, the functional expression of the SacMC(5) receptor was not negatively impacted when the receptor was co-expressed with a cartilaginous fish (Callorhinchus milii) MRAP2 cDNA. However, co-expression with either mouse mMRAP1 or zebrafish zfMRAP1 increased the sensitivity of SacMC(5) receptor for hACTH(1-24) by at least one order of magnitude. Hence, SacMC(5) receptor has the potential to interact with MRAP1 orthologs and in this regard behaved more like a melanocortin MC(2) receptor ortholog than a melanocortin MC(5) receptor ortholog. These observations are discussed in light of the evolution of the melanocortin receptor gene family in cartilaginous fish, and the physiological implications of these observations are considered.
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Affiliation(s)
- Christina L Reinick
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
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20
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Kumar A, Bhandari A, Sinha R, Goyal P, Grapputo A. Spliceosomal intron insertions in genome compacted ray-finned fishes as evident from phylogeny of MC receptors, also supported by a few other GPCRs. PLoS One 2011; 6:e22046. [PMID: 21850219 PMCID: PMC3151243 DOI: 10.1371/journal.pone.0022046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 06/16/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Insertions of spliceosomal introns are very rare events during evolution of vertebrates and the mechanisms governing creation of novel intron(s) remain obscure. Largely, gene structures of melanocortin (MC) receptors are characterized by intron-less architecture. However, recently a few exceptions have been reported in some fishes. This warrants a systematic survey of MC receptors for understanding intron insertion events during vertebrate evolution. METHODOLOGY/PRINCIPAL FINDINGS We have compiled an extended list of MC receptors from different vertebrate genomes with variations in fishes. Notably, the closely linked MC2Rs and MC5Rs from a group of ray-finned fishes have three and one intron insertion(s), respectively, with conserved positions and intron phase. In both genes, one novel insertion was in the highly conserved DRY motif at the end of helix TM3. Further, the proto-splice site MAG↑R is maintained at intron insertion sites in these two genes. However, the orthologs of these receptors from zebrafish and tetrapods are intron-less, suggesting these introns are simultaneously created in selected fishes. Surprisingly, these novel introns are traceable only in four fish genomes. We found that these fish genomes are severely compacted after the separation from zebrafish. Furthermore, we also report novel intron insertions in P2Y receptors and in CHRM3. Finally, we report ultrasmall introns in MC2R genes from selected fishes. CONCLUSIONS/SIGNIFICANCE The current repository of MC receptors illustrates that fishes have no MC3R ortholog. MC2R, MC5R, P2Y receptors and CHRM3 have novel intron insertions only in ray-finned fishes that underwent genome compaction. These receptors share one intron at an identical position suggestive of being inserted contemporaneously. In addition to repetitive elements, genome compaction is now believed to be a new hallmark that promotes intron insertions, as it requires rapid DNA breakage and subsequent repair processes to gain back normal functionality.
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Affiliation(s)
- Abhishek Kumar
- Department of Biology, University of Padua, Padova, Italy.
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21
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Veo K, Reinick C, Liang L, Moser E, Angleson JK, Dores RM. Observations on the ligand selectivity of the melanocortin 2 receptor. Gen Comp Endocrinol 2011; 172:3-9. [PMID: 21501611 DOI: 10.1016/j.ygcen.2011.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 03/31/2011] [Accepted: 04/01/2011] [Indexed: 11/29/2022]
Abstract
The melanocortin 2 receptor (MC2R) is unique in terms of ligand selectivity and in vitro expression in mammalian cell lines as compared to the other four mammalian MCRs. It is well established that ACTH is the only melanocortin ligand that can activate the ACTH receptor (i.e., melanocortin 2 receptor). Recent studies have provided new insights into the presence of a common binding site for the HFRW motif common to all melanocortin ligands. However, the activation of the melanocortin 2 receptor requires an additional amino acid motif that is only found in the sequence of ACTH. This mini-review will focus on these two topics and provide a phylogenetic perspective on the evolution of MC2R ligand selectivity.
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MESH Headings
- Amino Acid Sequence
- Animals
- Humans
- Ligands
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Membrane Proteins/physiology
- Molecular Sequence Data
- Observation
- Phylogeny
- Receptor, Melanocortin, Type 2/agonists
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 2/metabolism
- Receptor, Melanocortin, Type 2/physiology
- Receptors, Melanocortin/genetics
- Sequence Homology, Amino Acid
- Substrate Specificity
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Affiliation(s)
- Kristopher Veo
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
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22
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Dores RM, Baron AJ. Evolution of POMC: origin, phylogeny, posttranslational processing, and the melanocortins. Ann N Y Acad Sci 2011; 1220:34-48. [DOI: 10.1111/j.1749-6632.2010.05928.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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Kobayashi Y, Chiba H, Yamanome T, Schiöth HB, Takahashi A. Melanocortin receptor subtypes in interrenal cells and corticotropic activity of α-melanocyte-stimulating hormones in barfin flounder, Verasper moseri. Gen Comp Endocrinol 2011; 170:558-68. [PMID: 21118693 DOI: 10.1016/j.ygcen.2010.11.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/11/2010] [Accepted: 11/18/2010] [Indexed: 11/17/2022]
Abstract
The aim of this study was to characterize the pituitary-interrenal axis in barfin flounder, a flatfish. Adrenocorticotropic hormone (ACTH) and melanocortin 2 receptor (MC2R) have been shown to be indispensable substances in pituitary and interrenal cells for cortisol release, respectively. We previously identified ACTH in the pars distalis of the barfin flounder pituitary gland, and detected transcripts of Mc1r, Mc4r, and Mc5r in the head kidney wherein interrenal cells are located. We have now demonstrated the presence of MC2R, which is a specific receptor for ACTH, in interrenal cells by molecular cloning of Mc2r cDNA and in situ hybridization, and confirmation of the in vitro cortisol-releasing activity of ACTH. These results show the presence of a classical pituitary-interrenal axis in this fish. We also evaluated the role of α-melanocyte-stimulating hormone (α-MSH) and its related peptides. In situ hybridization was used to demonstrate the expression of Mc5r in interrenal cells; both desacetyl-α-MSH and diacetyl-α-MSH showed in vitro cortisol-releasing activities, while the activity of α-MSH was negligible. These findings indicate the presence of an additional pituitary-interrenal axis consisting of α-MSH-like peptides secreted from the neurointermediate lobe of the pituitary and MC5R in the interrenal cells. The cortisol-releasing activity of desacetyl-α-MSH and diacetyl-α-MSH, compared with the low activity of α-MSH, suggest a unique and specific functional role of these forms of MSH peptides. The interrenal co-expression of two subtypes of Mcrs may play a role in this specialization.
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Affiliation(s)
- Yuki Kobayashi
- School of Marin Biosciences, Kitasato University, Ofunato, Iwate 022-0101, Japan
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24
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Dores RM, Majeed Q, Komorowski L. Observations on the radiation of lobe-finned fishes, ray-finned fishes, and cartilaginous fishes: phylogeny of the opioid/orphanin gene family and the 2R hypothesis. Gen Comp Endocrinol 2011; 170:253-64. [PMID: 20937278 DOI: 10.1016/j.ygcen.2010.09.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 09/28/2010] [Accepted: 09/30/2010] [Indexed: 11/17/2022]
Abstract
At the close of the Devonian Period the rapid decline in the diversity of the lobe-finned fishes was countered by the emergence and diversification of the ray-finned fishes and the cartilaginous fishes that now dominate marine and freshwater ecosystems. All of these jawed vertebrates were derived from the ancestral gnathostomes; a chordate lineage that had experienced two genome duplication events during the evolution of the phylum. This review analyzes trends in the phylogeny of the opioid/orphanin gene family (four prohormone/neuropeptide precursor-coding genes) in the major classes of gnathostomes that survived the extinction events at the close of the Devonian Period and focuses on some features of this gene family that appear to set the cartilaginous fishes (class Chondrichthyes) apart from class Sarcopterygii (lobe-finned fishes and tetrapods) and class Actinopterygii (the ray-finned fishes).
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Affiliation(s)
- Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA.
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25
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Västermark A, Schiöth HB. The early origin of melanocortin receptors, agouti-related peptide, agouti signalling peptide, and melanocortin receptor-accessory proteins, with emphasis on pufferfishes, elephant shark, lampreys, and amphioxus. Eur J Pharmacol 2011; 660:61-9. [PMID: 21208605 DOI: 10.1016/j.ejphar.2010.10.106] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 09/30/2010] [Accepted: 10/12/2010] [Indexed: 01/07/2023]
Abstract
There are conflicting theories about the evolution of melanocortin MC receptors while only few studies have addressed the evolution of agouti-related peptide (AgRP) and agouti signalling peptide (ASIP), which are antagonists at the melanocortin receptors (MCRs), or the melanocortin MC(2) receptor accessory proteins (MRAP1 and MRAP2). Previously we have cloned melanocortin MC receptors (MC(a) and MC(b)) genes in river lamprey and here we identify orthologues to these melanocortin MC receptor sequences in the sea lamprey. We investigate the putative presence of the melanocortin MC receptor genes in lancelet (amphioxus; Branchiostoma floridae) but we find it unlikely that such gene exists, due to a sharp drop in sequence similarity beyond sequence clusters of known receptors. We show the presence of AgRP and ASIP in elephant shark, a cartilaginous fish belonging to the subclass of Elasmobranchii. However, we do not find any of these genes in lamprey or lancelet after detailed analysis of both targeted and whole proteome regular expression scans. We found MRAP2, but not MRAP1, to be present in elephant shark and sea lamprey while Fugu (T. rubripes) has both genes. This study shows that the most ancient presence of these melanocortin-related sequences is found in elephant shark and lampreys considering the current available sequence data.
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Affiliation(s)
- Ake Västermark
- Department of Neuroscience, BMC, Uppsala University, 751 24 Uppsala, Sweden.
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26
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Sebag JA, Hinkle PM. Opposite effects of the melanocortin-2 (MC2) receptor accessory protein MRAP on MC2 and MC5 receptor dimerization and trafficking. J Biol Chem 2009; 284:22641-8. [PMID: 19535343 DOI: 10.1074/jbc.m109.022400] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
MC2 (ACTH) receptors require MC2 receptor accessory protein (MRAP) to reach the cell surface. In this study, we show that MRAP has the opposite effect on the closely related MC5 receptor. In enzyme-linked immunosorbent assay and microscopy experiments, MC2 receptor was retained in the endoplasmic reticulum in the absence of MRAP and targeted to the plasma membrane with MRAP. MC5 receptor was at the plasma membrane in the absence of MRAP, but trapped intracellularly when expressed with MRAP. Using bimolecular fluorescence complementation, where one fragment of yellow fluorescent protein (YFP) was fused to receptors and another to MRAP, we showed that MC2 receptor-MRAP dimers were present at the plasma membrane, whereas MC5 receptor-MRAP dimers were intracellular. Both MC2 and MC5 receptors co-precipitated with MRAP. MRAP did not alter expression of beta2-adrenergic receptors or co-precipitate with them. To determine if MRAP affects formation of receptor oligomers, we co-expressed MC2 receptors fused to YFP fragments in the presence or absence of MRAP. YFP fluorescence, reporting MC2 receptor homodimers, was readily detectable with or without MRAP. In contrast, MC5 receptor homodimers were visible in the absence of MRAP, but little fluorescence was observed by microscopic analysis when MRAP was co-expressed. Co-precipitation of differentially tagged receptors confirmed that MRAP blocks MC5 receptor dimerization. The regions of MRAP required for its effects on MC2 and MC5 receptors differed. These results establish that MRAP forms stable complexes with two different melanocortin receptors, facilitating surface expression of MC2 receptor but disrupting dimerization and surface localization of MC5 receptor.
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Affiliation(s)
- Julien A Sebag
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642, USA
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