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Yao MX, Yu HX, Mo HL, Zhang ZH, Song QC, Liu Q, Yang QY, Wang LX, Li Y. Structural and pharmacological characterization of a medium-chain fatty acid receptor GPR84 in common carp (Cyprinus carpio). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2024; 153:105126. [PMID: 38160872 DOI: 10.1016/j.dci.2023.105126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 12/23/2023] [Accepted: 12/24/2023] [Indexed: 01/03/2024]
Abstract
The medium-chain fatty acid receptor GPR84, a member of the G protein-coupled receptor family, is mainly expressed in macrophages and microglia, and is involved in the regulation of inflammatory responses and retinal development in mammals and amphibians. However, structure, tissue distribution, and pharmacology of this receptor have rarely been reported in fish. In this study, we cloned the coding sequence (CDS) of common carp GPR84 (ccGPR84), examined its tissue distribution, and explored its cellular signaling function. The results showed that the CDS of ccGPR84 is 1191 bp and encodes a putative protein with 396 amino acids. Phylogenetic and chromosomal synteny analyses revealed that ccGPR84 was evolutionarily conserved with Cyprinids. Real-time quantitative PCR (qPCR) indicated that ccGPR84 was predominantly expressed in the intestine and spleen. Luciferase reporter assay demonstrated that nonanoic acid, capric acid (decanoic acid), undecanoic acid and lauric acid could inhibit cAMP signaling pathway and activate MAPK/ERK signaling pathway, while the potencies of these four fatty acids on the two signaling pathways were different. Lauric acid has the highest inhibitory potency on cAMP signaling pathway, followed by undecanoic acid, nonanoic acid, and capric acid. While for MAPK/ERK signaling pathway, nonanoic acid has the highest activation potency, followed by undecanoic acid, capric acid, and lauric acid. These findings lay the foundation for revealing the roles of different medium-chain fatty acids in the inflammatory response of common carp.
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Affiliation(s)
- Ming-Xing Yao
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Hui-Xia Yu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Hao-Lin Mo
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Zhi-Hao Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qing-Chuan Song
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qiao Liu
- Department of Pathology, The Second Affiliated Hospital of Air Force Medical University, Xi'an, Shaanxi, 710038, China
| | - Qi-Yuan Yang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts, Medical School, Worcester, MA, 01605, USA
| | - Li-Xin Wang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yang Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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Shaughnessy CA, Le K, Myhre VD, Dores RM. Functional characterization of melanocortin 2 receptor (Mc2r) from a lobe-finned fish (Protopterus annectens) and insights into the molecular evolution of melanocortin receptors. Gen Comp Endocrinol 2023; 343:114356. [PMID: 37562700 DOI: 10.1016/j.ygcen.2023.114356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/25/2023] [Accepted: 08/07/2023] [Indexed: 08/12/2023]
Abstract
Recent studies from our group on melanocortin 2 receptors (Mc2r) from basal families of actinopterygians have served to resolve that Mrap1 dependence and ACTH selectivity are features of even the most basal ray-finned fishes. However, there have been no studies on Mc2r function of the basal sarcopterygians, the lobe-finned fishes, represented by the extant members coelacanths and lungfishes. Here, we offer the first molecular and functional characterization of an Mc2r from a lobe-finned fish, the West African lungfish (Protopterus annectens). Plasmids containing cDNA constructs of lungfish (lf) Mc2r and Mrap1 were expressed in mammalian and zebrafish cell lines. Cells were then stimulated by human ACTH(1-24) and melanocyte stimulating hormone (α-MSH), as well as alanine-substituted analogs of hACTH(1-24) targeting residues within the H6F7R8W9 and K15K16R17R18P19 motifs. Activation of lfMc2r was assessed using a cAMP-responsive luciferase reporter gene assay. In these assays, lfMc2r required co-expression with lfMrap1, was selective for ACTH over α-MSH at physiological concentrations of the ligands, and was completely inhibited by multiple-alanine substitutions of the HFRW (A6-9) and KKRRP (A15-19) motifs. Single- and partial-alanine substitutions of the HFRW and KKRRP motifs varied in their impacts on receptor-ligand affinity from having no effect to completely inhibiting lfMc2r activation. This characterization of the Mc2r of a lobe-finned fish fulfills the last major extant vertebrate group for which Mc2r function had yet to be characterized. In doing so, we resolve that all basal bony vertebrate groups exhibit Mc2r function that substantially differs from that of the cartilaginous fishes, indicating that rapid and dramatic shift in Mc2r function occurred between the radiation of cartilaginous fishes and the emergence of bony fishes. We support this interpretation with a molecular clock analysis of the melanocortin receptors, which demonstrates the uniquely high rate of sequence divergence in Mc2r. Much remains to be understood regarding the molecular evolution of Mc2r during the early radiation of vertebrates that resulted in the derived functional characteristics of Mrap1 dependence and exclusive selectivity for ACTH.
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Affiliation(s)
| | - Khoa Le
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Valorie D Myhre
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO, USA
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3
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Bouyoucos IA, Shaughnessy CA, Gary Anderson W, Dores RM. Molecular and pharmacological analysis of the melanocortin-2 receptor and its accessory proteins Mrap1 and Mrap2 in a Squalomorph shark, the Pacific spiny dogfish. Gen Comp Endocrinol 2023; 342:114342. [PMID: 37454980 DOI: 10.1016/j.ygcen.2023.114342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/08/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
The hypothalamus-pituitary-adrenal/interrenal (HPA/I) axis is a conserved vertebrate neuroendocrine mechanism regulating the stress response. The penultimate step of the HPA/I axis is the exclusive activation of the melanocortin-2 receptor (Mc2r) by adrenocorticotropic hormone (ACTH), requiring an accessory protein, Mrap1 or Mrap2. Limited data for only three cartilaginous fishes support the hypothesis that Mc2r/Mrap1 function in bony vertebrates is a derived trait. Further, Mc2r/Mrap1 functional properties appear to contrast among cartilaginous fishes (i.e., the holocephalans and elasmobranchs). This study sought to determine whether functional properties of Mc2r/Mrap1 are conserved across elasmobranchs and in contrast to holocephalans. The deduced amino acid sequences of Pacific spiny dogfish (Squalus suckleyi; pd) pdMc2r, pdMrap1, and pdMrap2 were obtained from a de novo transcriptome of the interrenal gland and validated against the S. suckleyi genome. pdMc2r showed high primary sequence similarity with elasmobranch and holocephalan Mc2r except at extracellular domains 1 and 2, and transmembrane domain 5. pdMraps showed similarly high sequence similarity with holocephalan and other elasmobranch Mraps, with all cartilaginous fish Mrap1 orthologs lacking an activation motif. cAMP reporter gene assays demonstrated that pdMc2r requires an Mrap for activation, and can be activated by stingray (sr) ACTH(1-24), srACTH(1-13)NH2 (i.e., α-MSH), and γ-melanocyte-stimulating hormone at physiological concentrations. However, pdMc2r was three orders of magnitude more sensitive to srACTH(1-24) than srACTH(1-13)NH2. Further, pdMc2r was two orders of magnitude more sensitive to srACTH(1-24) when expressed with pdMrap1 than with pdMrap2. These data suggest that functional properties of pdMc2r/pdMrap1 reflect other elasmobranchs and contrast what is seen in holocephalans.
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Affiliation(s)
- Ian A Bouyoucos
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Bamfield Marine Sciences Centre, Bamfield, BC V0R 1B0, Canada.
| | | | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Bamfield Marine Sciences Centre, Bamfield, BC V0R 1B0, Canada
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
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Shaughnessy CA, Myhre VD, Hall DJ, McCormick SD, Dores RM. Hypothalamus-pituitary-interrenal (HPI) axis signaling in Atlantic sturgeon (Acipenser oxyrinchus) and sterlet (Acipenser ruthenus). Gen Comp Endocrinol 2023; 339:114290. [PMID: 37088167 DOI: 10.1016/j.ygcen.2023.114290] [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: 01/17/2023] [Revised: 03/27/2023] [Accepted: 04/19/2023] [Indexed: 04/25/2023]
Abstract
In vertebrates, the hypothalamic-pituitary-adrenal/interrenal (HPA/HPI) axis is a highly conserved endocrine axis that regulates glucocorticoid production via signaling by corticotropin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH). Once activated by ACTH, Gs protein-coupled melanocortin 2 receptors (Mc2r) present in corticosteroidogenic cells stimulate expression of steroidogenic acute regulatory protein (Star), which initiates steroid biosynthesis. In the present study, we examined the tissue distribution of genes involved in HPI axis signaling and steroidogenesis in the Atlantic sturgeon (Acipenser oxyrinchus) and provided the first functional characterization of Mc2r in sturgeon. Mc2r of A. oxyrinchus and the sterlet sturgeon (Acipenser ruthenus) are co-dependent on interaction with the melanocortin receptor accessory protein 1 (Mrap1) and highly selective for human (h) ACTH over other melanocortin ligands. A. oxyrinchus expresses key genes involved in HPI axis signaling in a tissue-specific manner that is indicative of the presence of a complete HPI axis in sturgeon. Importantly, we co-localized mc2r, mrap1, and star mRNA expression to the head kidney, indicating that this is possibly a site of ACTH-mediated corticosteroidogenesis in sturgeon. Our results are discussed in the context of other studies on the HPI axis of basal bony vertebrates, which, when taken together, demonstrate a need to better resolve the evolution of HPI axis signaling in vertebrates.
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Affiliation(s)
- Ciaran A Shaughnessy
- Department of Biological Sciences, University of Denver, Denver, CO, United States.
| | - Valorie D Myhre
- Department of Biological Sciences, University of Denver, Denver, CO, United States
| | - Daniel J Hall
- U.S. Geological Survey, Eastern Ecological Science Center, S. O. Conte Anadromous Fish Research Laboratory, Turners Falls, MA, USA
| | - Stephen D McCormick
- U.S. Geological Survey, Eastern Ecological Science Center, S. O. Conte Anadromous Fish Research Laboratory, Turners Falls, MA, USA; Department of Biology, University of Massachusetts, Amherst, MA, USA
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO, United States
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5
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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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6
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Dores RM, McKinley G, Meyers A, Martin M, Shaughnessy CA. Structure/Function Studies on the Activation Motif of Two Non-Mammalian Mrap1 Orthologs, and Observations on the Phylogeny of Mrap1, Including a Novel Characterization of an Mrap1 from the Chondrostean Fish, Polyodon spathula. Biomolecules 2022; 12:1681. [PMID: 36421695 PMCID: PMC9688151 DOI: 10.3390/biom12111681] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/03/2022] [Accepted: 11/09/2022] [Indexed: 08/12/2023] Open
Abstract
In derived bony vertebrates, activation of the melanocortin-2 receptor (Mc2r) by its ACTH ligand requires chaperoning by the Mc2r accessory protein (Mrap1). The N-terminal domain of the non-mammalian tetrapod MRAP1 from chicken (c; Gallus gallus) has the putative activation motif, W18D19Y20I21, and the N-terminal domain in the neopterygian ray-finned fish Mrap1 from bowfin (bf; Amia calva) has the putative activation motif, Y18D19Y20I21. The current study used an alanine-substitution paradigm to test the hypothesis that only the Y20 position in the Mrap1 ortholog of these non-mammalian vertebrates is required for activation of the respective Mc2r ortholog. Instead, we found that for cMRAP1, single alanine-substitution resulted in a gradient of inhibition of activation (Y20 >> D19 = W18 > I21). For bfMrap1, single alanine-substitution also resulted in a gradient of inhibition of activation (Y20 >> D19 > I21 > Y18). This study also included an analysis of Mc2r activation in an older lineage of ray-finned fish, the paddlefish (p), Polyodon spathula (subclass Chondronstei). Currently no mrap1 gene has been found in the paddlefish genome. When pmc2r was expressed alone in our CHO cell/cAMP reporter gene assay, no activation was observed following stimulation with ACTH. However, when pmc2r was co-expressed with either cmrap1 or bfmrap1 robust dose response curves were generated. These results indicate that the formation of an Mc2r/Mrap1 heterodimer emerged early in the radiation of the bony vertebrates.
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Affiliation(s)
- Robert M. Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
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7
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Shaughnessy CA, Jensen MF, Dores RM. A basal actinopterygian melanocortin receptor: Molecular and functional characterization of an Mc2r ortholog from the Senegal bichir (Polypterus senegalus). Gen Comp Endocrinol 2022; 328:114105. [PMID: 35973587 DOI: 10.1016/j.ygcen.2022.114105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 12/14/2022]
Abstract
In bony vertebrates, melanocortin 2 receptor (Mc2r) specifically binds adrenocorticotropic hormone (ACTH) and is responsible for mediating anterior pituitary signaling that stimulates corticosteroid production in the adrenal gland/interrenal cells. In bony fishes Mc2r requires the chaperoning of an accessory protein (Mrap1) to traffic to the membrane surface and bind ACTH. Here, we evaluated the structure and pharmacological properties of Mc2r from the Senegal bichir (Polypterus senegalus), which represents the most basal bony fish from which an Mc2r has been pharmacologically studied to date. In our experiments, cDNA constructs of the Mc2r from the Senegal bichir (sbMc2r) and various vertebrate Mrap1s were heterologously co-expressed in Chinese hamster ovary (CHO) cells, stimulated by ACTH or melanocyte-stimulating hormone (α-MSH) ligands, and assessed using a luciferase reporter gene assay. When expressed without an Mrap1, sbMc2r was not activated by ACTH. When co-expressed with Mrap1 from either chicken (Gallus gallus) or bowfin (Amia calva), sbMc2r could be activated in a dose-dependent manner by ACTH, but not α-MSH. Co-expression of sbMrap2 with sbMc2r resulted in no detectable activation of the receptor. Collectively, these results demonstrate that sbMc2r has pharmacological properties similar to those of Mc2rs of later-evolved bony fishes, such as Mrap1 dependence and ACTH selectivity, indicating that these qualities of Mc2r function are ancestral to all bony fish Mc2rs.
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Affiliation(s)
| | - Mary F Jensen
- Department of Biological Sciences, University of Denver, Denver, CO
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO
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8
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Kwok-Shing Wong M, Dores RM. Analyzing the Hypothalamus/Pituitary/Interrenal axis of the neopterygian fish, Lepisosteus oculatus: Co-localization of MC2R, MC5R, MRAP1, and MRAP2 in interrenal cells. Gen Comp Endocrinol 2022; 323-324:114043. [PMID: 35447133 DOI: 10.1016/j.ygcen.2022.114043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/10/2022] [Accepted: 04/14/2022] [Indexed: 11/19/2022]
Abstract
RT-PCR analysis indicated that steroidogenic tissues are located along the length of the kidney of the neopterygian fish, Lepisosteus oculatus (spotted gar; g). However, RT-PCR analysis of the distribution of mc2r mRNA and mrap1 mRNA, critical components of the gar hypothalamus/pituitary/interrenal (HPI) axis, was only associated with the anterior and medial regions of the kidney. Steroidogenic cells were designated as interrenal cells that possess star mRNA (in situ hybridization) and lipid vesicles (histological analysis) within the kidney. RT-PCR also detected mc5r mRNA along the length of the tissues associated with the kidney. In situ hybridization analysis of the putative interrenal cells revealed co-expression of mc2r, and mc5r mRNAs in the same steroidogenic cells. Co-expression of gar Mc2r (gMc2r) and Mrap1 (gMrap1) in Chinese Hamster Ovary (CHO) cells stimulated with ACTH(1-24) resulted in activation with an EC50 value of 1.0 × 10-11M +/- 4.6 × 10-11); whereas stimulation of CHO cells co-expressed with gar Mc5r (gMc5r) and gMrap1 and stimulated with ACTH(1-24) resulted in an EC50 value that was 3 orders of magnitude lower (2.1 × 10-8 M +/- 3.5 × 10-9). Interesting, when CHO cells were co-transfected with gMc2r, gMc5r, and gMrap1 there was a decline in activation as measured by the Vmax values for CHO cells stimulated with either ACTH(1-24) or α-MSH. These results suggest that some interaction may occur between gMc2r and gMc5r when both receptors are expressed in the same cells. Phylogenetic and selection pressure analyses of vertebrate mc2r and mc5r genes concluded that the two genes are evolving at different rates after duplication from a proposed common ancestral gene.
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Affiliation(s)
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, USA.
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9
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Hoglin BE, Miner M, Dores RM. Pharmacological properties of whale shark (Rhincodon typus) melanocortin-2 receptor and melancortin-5 receptor: Interaction with MRAP1 and MRAP2. Gen Comp Endocrinol 2022; 315:113915. [PMID: 34607718 DOI: 10.1016/j.ygcen.2021.113915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
In the current study, the whale shark (ws; Rhincodon typus) melanocortin-2 receptor (MC2R) co-expressed with wsMRAP1 in Chinese Hamster Ovary (CHO) Cells could be stimulated in a dose dependent manner by ACTH(1-24) with an EC50 of 2.6 × 10-10 M ± 9.7 × 10-11. When the receptor was expressed alone, stimulation was only observed at [10-6 M]. A comparable increase in sensitivity to stimulation by srDes-Ac-αMSH was also observed when the receptor was co-expressed with wsMRAP1. Furthermore, co-expression with wsMRAP1 significantly increased the trafficking of wsMC2R to the plasma membrane of CHO cells. Surprisingly, co-expression with wsMRAP2 also increased sensitivity to stimulation by ACTH(1-24) and srDes-Ac-αMSH, and increased trafficking of the receptor to the plasma membrane. These observations are in sharp contrast to the response of MC2R orthologs of bony vertebrates which have an obligate requirement for co-expression with MRAP1 for both trafficking to the plasma membrane and activation, whereas, co-expression with MRAP2 increases trafficking, but has minimal effects on activation. In addition, when comparing the activation features of wsMC2R with those of the elephant shark MC2R and red stingray MC2R orthologs, both similarities and differences are observed. The spectrum of features for cartilaginous fish MC2R orthologs will be discussed. A second objective of this study was to determine whether wsMC5R has features in common with wsMC2R in terms of ligand selectivity and interaction with wsMRAP paralogs. While wsMC5R can be activated by either srACTH(1-24) or srDes-Ac-αMSH, and co-expression with wsMRAP1 enhances this activation, wsMRAP1 had no effect on the trafficking of wsMC5R. In addition, co-expression with wsMRAP2 had no positive or negative effect on either ligand sensitivity or trafficking of wsMC5R.
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Affiliation(s)
- Brianne E Hoglin
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Marin Miner
- 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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Dores RM, Chapa E. Hypothesis and Theory: Evaluating the Co-Evolution of the Melanocortin-2 Receptor and the Accessory Protein MRAP1. Front Endocrinol (Lausanne) 2021; 12:747843. [PMID: 34790168 PMCID: PMC8591103 DOI: 10.3389/fendo.2021.747843] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/20/2021] [Indexed: 11/24/2022] Open
Abstract
The melanocortin receptors (MCRs) and the MRAP accessory proteins belong to distinct gene families that are unique to the chordates. During the radiation of the chordates, the melancortin-2 receptor paralog (MC2R) and the MRAP1 paralog (melanocortin-2 receptor accessory protein 1) have co-evolved to form a heterodimer interaction that can influence the ligand selectivity and trafficking properties of MC2R. This apparently spontaneous interaction may have begun with the ancestral gnathostomes and has persisted in both the cartilaginous fishes and the bony vertebrates. The ramifications of this interaction had profound effects on the hypothalamus/anterior pituitary/adrenal-interrenal axis of bony vertebrates resulting in MC2R orthologs that are exclusively selective for the anterior pituitary hormone, ACTH, and that are dependent on MRAP1 for trafficking to the plasma membrane. The functional motifs within the MRAP1 sequence and their potential contact sites with MC2R are discussed. The ramifications of the MC2R/MRAP1 interaction for cartilaginous fishes are also discussed, but currently the effects of this interaction on the hypothalamus/pituitary/interrenal axis is less clear. The cartilaginous fish MC2R orthologs have apparently retained the ability to be activated by either ACTH or MSH-sized ligands, and the effect of MRAP1 on trafficking varies by species. In this regard, the possible origin of the dichotomy between cartilaginous fish and bony vertebrate MC2R orthologs with respect to ligand selectivity and trafficking properties is discussed in light of the evolution of functional amino acid motifs within MRAP1.
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Hoglin BE, Miner M, Dores RM. Pharmacological properties of whale shark (Rhincodon typus) melanocortin-2 receptor and melancortin-5 receptor: Interaction with MRAP1 and MRAP2. Gen Comp Endocrinol 2020; 293:113463. [PMID: 32213301 DOI: 10.1016/j.ygcen.2020.113463] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 02/18/2020] [Accepted: 03/10/2020] [Indexed: 11/28/2022]
Abstract
In the current study, the whale shark (ws; Rhincodon typus) melanocortin-2 receptor (MC2R) co-expressed with wsMRAP1 in Chinese Hamster Ovary (CHO) Cells could be stimulated in a dose dependent manner by ACTH(1-24) with an EC50 of 2.6 × 10-10 M ± 9.7 × 10-11. When the receptor was expressed alone, stimulation was only observed at [10-6 M]. A comparable increase in sensitivity to stimulation by srDes-Ac-αMSH was also observed when the receptor was co-expressed with wsMRAP1. In addition, co-expression with wsMRAP1 significantly increased the trafficking of wsMC2R to the plasma membrane of CHO cells. Surprisingly, co-expression with wsMRAP2 also increased sensitivity to stimulation by ACTH(1-24) and srDes-Ac-αMSH, and increased trafficking of the receptor to the plasma membrane. These observations are in sharp contrast to the response of MC2R orthologs of bony vertebrates which have an obligate requirement for co-expression with MRAP1 for both trafficking to the plasma membrane and activation, and while co-expression with MRAP2 increases trafficking, it has minimal effects on activation. In addition, when comparing the activation features of wsMC2R with those of the elephant shark MC2R and red stingray MC2R orthologs, both similarities and differences are observed. The spectrum of features for cartilaginous fish MC2R orthologs will be discussed. A second objective of this study was to determine whether wsMC5R has features in common with wsMC2R in terms of ligand selectivity and interaction with wsMRAP paralogs. While wsMC5R can be activated by either srACTH(1-24) or srDes-Ac-αMSH, and co-expression with wsMRAP1 enhances this activation, wsMRAP1 had no effect on the trafficking of wsMC5R. Co-expression with wsMRAP2 had no positive or negative effect on either ligand sensitivity or trafficking of wsMC5R.
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Affiliation(s)
- Brianne E Hoglin
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Marin Miner
- 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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12
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Hoglin BE, Ferguson A, Pahlavan S, Dores RM. Evidence for diversity in the activation of the melanocortin 2 receptor: A study on gar, elephant shark and stingray MC2Rs. Peptides 2020; 124:170209. [PMID: 31778725 DOI: 10.1016/j.peptides.2019.170209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/28/2019] [Accepted: 11/21/2019] [Indexed: 12/21/2022]
Abstract
The melanocortin-2 receptor (MC2R) is a critical component of the HPI and HPA axes of cartilaginous fishes, teleosts and tetrapods. Studies on teleost and tetrapod orthologs suggest two contact sites between ACTH and the receptor involving the following motifs on ACTH: H6F7R8W9 and K15K16R17R18P19. Using spotted gar (g) MC2R as a representative bony fish MC2R ortholog, we found that activation of gMC2R in Chinese Hamster Ovary (CHO) cells was diminished following stimulation of the transfected cells with hACTH(1-24) analogs substituted with alanine at either the H6F7R8W9 or K15K16R17R18P19 motifs compared to stimulation with hACTH(1-24). This observation suggests two ligand contact sites necessary for activation of the gMC2R. The same experiments were done with elephant shark (es) MC2R, however only the H6F7R8W9 analogs blocked activation, pointing to a single contact on esMC2R. Conversely, the red stingray (sr) MC2R activation was blocked by both the H6F7R8W9 and K15K16R17R18P19 alanine-substituted analogs. Together these results build a picture of the evolution of the ligand and receptor interaction between ACTH and MC2R orthologs of different taxa. These results will be discussed in light of the parallel evolution of MC2R orthologs in cartilaginous fishes and bony vertebrates.
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Affiliation(s)
- Brianne E Hoglin
- University of Denver, Department of Biological Sciences, Denver, Colorado, 80210, USA
| | - Amanda Ferguson
- University of Denver, Department of Biological Sciences, Denver, Colorado, 80210, USA
| | - Sheila Pahlavan
- University of Denver, Department of Biological Sciences, Denver, Colorado, 80210, USA
| | - Robert M Dores
- University of Denver, Department of Biological Sciences, Denver, Colorado, 80210, USA.
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13
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Ji LQ, Rao YZ, Zhang Y, Chen R, Tao YX. Regulation of melanocortin-1 receptor pharmacology by melanocortin receptor accessory protein 2 in orange-spotted grouper (Epinephelus coioides). Gen Comp Endocrinol 2020; 285:113291. [PMID: 31568758 DOI: 10.1016/j.ygcen.2019.113291] [Citation(s) in RCA: 8] [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: 08/17/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 02/06/2023]
Abstract
Melanocortin-1 receptor (MC1R) has important roles in regulating pigmentation and inflammation. Melanocortin receptor accessory protein 2 (MRAP2) modulates trafficking, ligand binding, and signaling of mammalian melanocortin receptors. However, the effect of MRAP2 on fish MC1R has not been extensively studied. Herein, we cloned the orange-spotted grouper (Epinephelus coioides) mc1r, which had a 972 bp open reading frame encoding a putative protein of 323 amino acids. Grouper mc1r was mainly expressed in the brain, skin, testis, spleen, head kidney, and kidney. EcoMC1R showed high constitutive activities in both Gs-cAMP and ERK1/2 pathways, which could be differentially modulated by grouper MRAP2 (EcoMRAP2). Three agonists, including α-melanocyte-stimulating hormone (MSH), β-MSH, and ACTH, could bind to EcoMC1R and dose-dependently increase intracellular cAMP production. EcoMRAP2 had no effect on the IC50 in binding assay or EC50 in cAMP assay; however, it dose-dependently decreased the cell surface expression and maximal response to the three agonists. EcoMRAP2 increased basal ERK1/2 activation but did not alter α-MSH-stimulated ERK1/2 activation. This study extends the knowledge base of fish MC1R pharmacology and its regulation by MRAP2.
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Affiliation(s)
- Li-Qin Ji
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States; Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Ying-Zhu Rao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States; Institute of Applied Biotechnology, Life Science and Technology School, Lingnan Normal University, Zhanjiang 524048, Guangdong, China
| | - Yong Zhang
- Southern Laboratory of Ocean Science and Engineering (Zhuhai, Guangdong), Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Zhuhai 51900, China
| | - Rong Chen
- Institute of Applied Biotechnology, Life Science and Technology School, Lingnan Normal University, Zhanjiang 524048, Guangdong, China
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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14
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Barney E, Dores MR, McAvoy D, Davis P, Racareanu RC, Iki A, Hyodo S, Dores RM. Elephant shark melanocortin receptors: Novel interactions with MRAP1 and implication for the HPI axis. Gen Comp Endocrinol 2019; 272:42-51. [PMID: 30468718 DOI: 10.1016/j.ygcen.2018.11.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/15/2018] [Accepted: 11/16/2018] [Indexed: 10/27/2022]
Abstract
The presence of Mrap1 and Mrap2 orthologs in the genome of the elephant shark (es), a cartilaginous fish, presented an opportunity to evaluate the potential interactions between these accessory proteins and melanocortin receptors of a cartilaginous fish. RT-PCR analysis indicated that Mrap1 mRNA was present in interrenal, brain, and pituitary tissue with mRNA for Mc2R, Mc3R, Mc4R, and Mc5r. Co-expression of esMrap1 cDNA with esMc2r cDNA or esMc5r cDNA in CHO cells increased sensitivity to stimulation with ACTH(1-24) 10 fold and 100 fold, respectfully, but had no effect on sensitivity to stimulation with DesAc-αMSH [i.e., ACTH(1-13)NH2] for either receptor, and had no effect on the ligand sensitivity of either esMc3r or esMc4r. Fluorescence image analysis indicated co-localization of esMrap1/esMc2r, and esMrap1/esMc5r on the plasma membrane; however, cell surface ELISA analysis indicated that co-expression with esMrap1 had no effect, positive or negative, on the trafficking of either esMc2r or esMc5r to the plasma membrane. RT-PCR analysis also indicated that Mrap2 mRNA, as well as, mRNAs for Mc2r, Mc3r, Mc4r, and Mc5r could be detected in brain tissue, however no Mrap2 mRNA was detected in interrenal tissue. Co-expression of esMrap2 in CHO cells with, respectively, esMc2r, esMc4r, or esMc5r had no effect on ligand sensitivity. However, co-expression of esMrap2 with esMc3r did lower sensitivity to stimulation by DesAc-αMSH 10 fold. These observations are discussed in the context of the parallel evolution of melanocortin receptors and their accessory proteins, and the hypothalamus/pituitary/adrenal axis and the hypothalamus/pituitary/interrenal axis in bony vertebrates and cartilaginous fishes.
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Affiliation(s)
- Emily Barney
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Michael R Dores
- Department of Biology, Hofstra University, Hampstead, NY, USA
| | - Danielle McAvoy
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Perry Davis
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | | | - Ayuko Iki
- Atmosphere and Ocean Research Institute, University of Tokyo, Chiba, Japan
| | - Susumu Hyodo
- Atmosphere and Ocean Research Institute, University of Tokyo, Chiba, Japan
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO, USA.
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15
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Dores RM, Scuba-Gray M, McNally B, Davis P, Takahashi A. Evaluating the interactions between red stingray (Dasyatis akajei) melanocortin receptors and elephant shark (Callorhinchus milii) MRAP1 and MRAP2 following stimulation with either stingray ACTH(1-24) or stingray Des-Acetyl-αMSH: A pharmacological study in Chinese Hamster Ovary cells. Gen Comp Endocrinol 2018. [PMID: 29524525 DOI: 10.1016/j.ygcen.2018.02.018] [Citation(s) in RCA: 12] [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] [Indexed: 01/10/2023]
Abstract
Previous studies on bony vertebrate MC2R orthologs (i.e., ray finned fishes, amphibians, reptiles, birds, and mammals) have shown that these MC2R orthologs have an obligatory requirement for interaction with bony vertebrate MRAP1 orthologs to a) allow for the trafficking of the MC2R ortholog to the plasma membrane; and b) to allow activation by ACTH, but not by any MSH-sized ligand. In addition, previous studies have found that co-expression of teleost and mammalian MC4R orthologs with corresponding MRAP2 has positive effects on sensitivity to stimulation by αMSH or ACTH. MRAP1 and MRAP2 paralogs have been detected in the genome of a cartilaginous fish (elephant shark), yet two cartilaginous fish MC2R orthologs (elephant shark and red stingray) do not apparently require MRAP1 for trafficking to the plasma membrane when expressed in Chinese Hamster Ovary (CHO) cells, and both orthologs can be activated by either ACTH or MSH-sized ligands. This study was done to determine whether sensitivity to stimulation by ACTH(1-24) or Des-Acetyl-αMSH is affected when stingray (sr) MC1R, MC2R, MC3R, MC4R or MC5R were co-expressed in CHO cells with either elephant shark (es) MRAP1 or esMRAP2. The results indicated that co-expression with heterologous MRAP1 increased the sensitivity of all five stingray melanocortin receptors for srACTH(1-24), but had not statistically significant effect on stimulation by srDes-Acetyl-αMSH for any of the stingray melanocortin receptors. Conversely, co-expression with esMRAP2 only enhanced sensitivity for srDes-Acetyl-αMSH for srMC4R, but had no effect on the other stingray orthologs, and there was no increase in sensitivity for srACTH(1-24) for any of the stingray melanocortin receptors. It appears then that some stingray melanocortin receptors have retained the ability to interact with a cartilaginous MRAP1 paralog. These results are discussed with reference to radiation of MRAP-related accessory proteins in cartilaginous fishes.
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Affiliation(s)
- Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO, USA.
| | | | - Bridgette McNally
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Perry Davis
- Department of Biological Sciences, University of Denver, Denver, CO, USA
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16
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Buechi HB, Bridgham JT. Evolution of specificity in cartilaginous fish glycoprotein hormones and receptors. Gen Comp Endocrinol 2017; 246:309-320. [PMID: 28062301 DOI: 10.1016/j.ygcen.2017.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/01/2016] [Accepted: 01/02/2017] [Indexed: 01/01/2023]
Abstract
Glycoprotein hormones (GpH) interact very specifically with their receptors to mediate hypothalamic-pituitary-peripheral gland endocrine signaling. Vertebrates typically have three functionally distinct GpH endocrine signaling complexes: follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone, and their receptors. Each hormone consists of a common α subunit bound to one of three different β subunits. Individual hormone subunits and receptors are present in genomes of early metazoans, and a subset of hormone subunits and receptors has been recently characterized in sea lamprey. However, it remains unclear when the full complement of hormone and receptor protein families first appeared, and when specificity of interactions between GpH hormones and receptors first evolved. Here we present phylogenetic analyses showing that the elephant shark (Callorhinchus milii) genome contains sequences representing the current diversity of all hormone subunits and receptors in these co-evolving protein families. We examined specificity of hormone and receptor interactions using functional assays testing reporter gene activation by elephant shark follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone receptors. We show highly specific, dose-responsive hormone interactions for all three complexes. Our results suggest that co-evolution of specificity between proteins in these endocrine signaling complexes occurred prior to the divergence of Chondrichthyes from the chordate lineage.
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Affiliation(s)
- Hanna B Buechi
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Jamie T Bridgham
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
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17
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Ren J, Li Y, Xu N, Li H, Li C, Han R, Wang Y, Li Z, Kang X, Liu X, Tian Y. Association of estradiol on expression of melanocortin receptors and their accessory proteins in the liver of chicken (Gallus gallus). Gen Comp Endocrinol 2017; 240:182-190. [PMID: 27793723 DOI: 10.1016/j.ygcen.2016.10.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 10/18/2016] [Accepted: 10/24/2016] [Indexed: 12/31/2022]
Abstract
The melanocortin receptor accessory proteins (MRAP and MRAP2) are small single-pass transmembrane proteins that regulate the biological functions of the melanocortin receptor (MCR) family. MCRs comprise five receptors (MC1R-MC5R) with diverse physiological roles in mammals. Five MCR members and two MRAPs were also predicted in the chicken (Gallus gallus) genome. However, little is known about their expression, regulation and biological functions. In this study, we cloned the MRAP and MRAP2 genes. Sequencing analysis revealed that the functional domains of MRAP and MRAP2 were conserved among species, suggesting that the physiological roles of chicken MRAP and MRAP2 could be similar to their mammalian counterparts. Tissue expression analysis demonstrated that MRAP was expressed in the adrenal gland, liver, spleen, glandular stomach and lungs, while MRAP2 is predominantly expressed in the adrenal gland. All five MCRs were present in the adrenal gland, but showed different expression patterns in other tissues. The MC5R was the only MCR member that was expressed in the chicken liver. The expression levels of MRAP in chicken liver were significantly increased at sexual maturity stage, and were significantly up-regulated (P<0.05) when chickens and chicken primary hepatocytes were treated with 17β-estradiol in vivo and in vitro, respectively; however, expression levels of PPARγ were down-regulated, and no effect on MC5R was observed. Our results suggested that estrogen could stimulate the expression of MRAP in the liver of chicken through inhibiting the expression of transcription regulation factor PPARγ, and MRAP might play its biological role in a different way rather than forming an MRAP/MC2R complex in chicken liver during the egg-laying period.
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MESH Headings
- Amino Acid Sequence
- Animals
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Chickens/genetics
- Cloning, Molecular
- Estradiol/pharmacology
- Gene Expression Profiling
- Gene Expression Regulation, Developmental/drug effects
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Humans
- Liver/drug effects
- Liver/metabolism
- PPAR gamma/genetics
- PPAR gamma/metabolism
- Phylogeny
- Receptor, Melanocortin, Type 2/chemistry
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 2/metabolism
- Receptors, Melanocortin/chemistry
- Receptors, Melanocortin/genetics
- Receptors, Melanocortin/metabolism
- Sequence Alignment
- Tissue Distribution/drug effects
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Affiliation(s)
- Junxiao Ren
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Yanmin Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Naiyi Xu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Hong Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Cuicui Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Ruili Han
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Henan Agricultural University, Zhengzhou 450002, China; International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou 450002, China
| | - Yanbin Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Henan Agricultural University, Zhengzhou 450002, China; International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou 450002, China
| | - Zhuanjian Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Henan Agricultural University, Zhengzhou 450002, China; International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou 450002, China
| | - Xiangtao Kang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Henan Agricultural University, Zhengzhou 450002, China; International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou 450002, China
| | - Xiaojun Liu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Henan Agricultural University, Zhengzhou 450002, China; International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou 450002, China.
| | - Yadong Tian
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Henan Agricultural University, Zhengzhou 450002, China; International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou 450002, China.
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18
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Takahashi A, Davis P, Reinick C, Mizusawa K, Sakamoto T, Dores RM. Data for amino acid alignment of Japanese stingray melanocortin receptors with other gnathostome melanocortin receptor sequences, and the ligand selectivity of Japanese stingray melanocortin receptors. Data Brief 2016; 7:1670-7. [PMID: 27408924 PMCID: PMC4927774 DOI: 10.1016/j.dib.2016.04.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 04/14/2016] [Accepted: 04/19/2016] [Indexed: 11/27/2022] Open
Abstract
This article contains structure and pharmacological characteristics of melanocortin receptors (MCRs) related to research published in “Characterization of melanocortin receptors from stingray Dasyatis akajei, a cartilaginous fish” (Takahashi et al., 2016) [1]. The amino acid sequences of the stingray, D. akajei, MC1R, MC2R, MC3R, MC4R, and MC5R were aligned with the corresponding melanocortin receptor sequences from the elephant shark, Callorhinchus milii, the dogfish, Squalus acanthias, the goldfish, Carassius auratus, and the mouse, Mus musculus. These alignments provide the basis for phylogenetic analysis of these gnathostome melanocortin receptor sequences. In addition, the Japanese stingray melanocortin receptors were separately expressed in Chinese Hamster Ovary cells, and stimulated with stingray ACTH, α-MSH, β-MSH, γ-MSH, δ-MSH, and β-endorphin. The dose response curves reveal the order of ligand selectivity for each stingray MCR.
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Affiliation(s)
- Akiyoshi Takahashi
- School of Marine Biosciences, Kitasato Universtiy, Sagaminara 252-0373, Japan
| | - Perry Davis
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Christina Reinick
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Kanta Mizusawa
- School of Marine Biosciences, Kitasato Universtiy, Sagaminara 252-0373, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute, Faculty of Sciences, Okayama University, Ushimado, Setouchi 701-4303, Japan
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
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19
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Takahashi A, Davis P, Reinick C, Mizusawa K, Sakamoto T, Dores RM. Characterization of melanocortin receptors from stingray Dasyatis akajei, a cartilaginous fish. Gen Comp Endocrinol 2016; 232:115-24. [PMID: 27021018 DOI: 10.1016/j.ygcen.2016.03.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/22/2016] [Accepted: 03/24/2016] [Indexed: 11/27/2022]
Abstract
Melanocortin (MC) systems are composed of MC peptides such as adrenocorticotropic hormone (ACTH), several molecular forms of melanocyte-stimulating hormones (MSHs) and MC receptors (MCRs). Here we demonstrated that the cartilaginous fish, Dasyatis akajei (stingray) expresses five subtypes of MCR genes-mc1r to mc5r-as in the case of teleost and tetrapod species. This is the first evidence showing the presence of the full repertoire of melanocortin receptors in a single of cartilaginous fish. Expression of respective stingray mcr cDNAs in Chinese hamster ovary cells revealed that Des-acetyl-α-MSH exhibited cAMP-producing activity indistinguishable to ACTH(1-24) on MC1R and MC2R, while the activity of Des-acetyl-α-MSH on MC3R, MC4R, and MC5R were similar to or slightly greater than that of ACTH(1-24). Notably, in contrast to the other vertebrates, MC2R did not require coexpression with a melanocortin receptor-2 accessory protein 1 (mrap1) cDNA for functional expression. One of the roles of MC system resides in regulation of the pituitary-interrenal (PI) axis-a homologue of tetrapod pituitary-adrenal axis. In stingray, interrenal tissues were shown to express mc2r and mc5r as major MCR genes. These results established the presence of functional PI axis in stingray at the level of receptor molecule. While MC2R participates in adrenal functions together with MRAP1 in tetrapod species, the fact that sensitivity of MC5R to Des-acetyl-α-MSH and ACTH(1-24) were two order of magnitude higher than MC2R without coexpression with MRAP1 suggested that MC5R could play a more important role than MC2R to transmit signals conveyed by ACTH and MSHs if MRAP1 is really absent in the stingray.
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Affiliation(s)
- Akiyoshi Takahashi
- School of Marine Biosciences, Kitasato University, Sagaminara 252-0373, Japan.
| | - Perry Davis
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Christina Reinick
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Kanta Mizusawa
- School of Marine Biosciences, Kitasato University, Sagaminara 252-0373, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute, Faculty of Science, Okayama University, Ushimado, Setouchi 701-4303 Japan
| | - Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO, USA
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20
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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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23
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Malik S, Dolan TM, Maben ZJ, Hinkle PM. Adrenocorticotropic Hormone (ACTH) Responses Require Actions of the Melanocortin-2 Receptor Accessory Protein on the Extracellular Surface of the Plasma Membrane. J Biol Chem 2015; 290:27972-85. [PMID: 26424796 DOI: 10.1074/jbc.m115.668491] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Indexed: 01/26/2023] Open
Abstract
The melanocortin-2 (MC2) receptor is a G protein-coupled receptor that mediates responses to ACTH. The MC2 receptor acts in concert with the MC2 receptor accessory protein (MRAP) that is absolutely required for ACTH binding and signaling. MRAP has a single transmembrane domain and forms a highly unusual antiparallel homodimer that is stably associated with MC2 receptors at the plasma membrane. Despite the physiological importance of the interaction between the MC2 receptor and MRAP, there is little understanding of how the accessory protein works. The dual topology of MRAP has made it impossible to determine whether highly conserved and necessary regions of MRAP are required on the intracellular or extracellular face of the plasma membrane. The strategy used here was to fix the orientation of two antiparallel MRAP molecules and then introduce inactivating mutations on one side of the membrane or the other. This was achieved by engineering proteins containing tandem copies of MRAP fused to the amino terminus of the MC2 receptor. The data firmly establish that only the extracellular amino terminus (Nout) copy of MRAP, oriented with critical segments on the extracellular side of the membrane, is essential. The transmembrane domain of MRAP is also required in only the Nout orientation. Finally, activity of MRAP-MRAP-MC2-receptor fusion proteins with inactivating mutations in either MRAP or the receptor was rescued by co-expression of free wild-type MRAP or free wild-type receptor. These results show that the basic MRAP-MRAP-receptor signaling unit forms higher order complexes and that these multimers signal.
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Affiliation(s)
- Sundeep Malik
- From the Department of Pharmacology and Physiology, University of Rochester Medical Center Rochester, New York 14642
| | - Terrance M Dolan
- From the Department of Pharmacology and Physiology, University of Rochester Medical Center Rochester, New York 14642
| | - Zachary J Maben
- From the Department of Pharmacology and Physiology, University of Rochester Medical Center Rochester, New York 14642
| | - Patricia M Hinkle
- From the Department of Pharmacology and Physiology, University of Rochester Medical Center Rochester, New York 14642
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24
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Dores RM, Garcia Y. Views on the co-evolution of the melanocortin-2 receptor, MRAPs, and the hypothalamus/pituitary/adrenal-interrenal axis. Mol Cell Endocrinol 2015; 408:12-22. [PMID: 25573240 DOI: 10.1016/j.mce.2014.12.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/26/2014] [Accepted: 12/27/2014] [Indexed: 12/30/2022]
Abstract
A critical regulatory component of the hypothalamus/pituitary/adrenal axis (HPA) in mammals, reptiles and birds, and in the hypothalamus/pituitary/interrenal (HPI) axis of amphibians and teleosts (modern bony fishes) is the strict ligand selectivity of the melanocortin-2 receptor (MC2R). Tetrapod and teleost MC2R orthologs can only be activated by the anterior pituitary hormone, ACTH, but not by any of the MSH-sized ligands coded in POMC. In addition, both tetrapod and teleost MC2R orthologs require co-expression with the accessory protein, MRAP. However, the MC2R ortholog of the elephant shark, a cartilaginous fish, can be activated by either ACTH or the MSH-sized ligands, and the elephant shark MC2R ortholog does not require co-expression with an MRAP for activation. Given these observations, this review will provide a scenario for the co-evolution of MC2R and MRAP, based on the assumption that the obligate interaction between MC2R and MRAP evolved during the early radiation of the ancestral bony fishes.
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Affiliation(s)
- Robert M Dores
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA.
| | - Yesenia Garcia
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
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25
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Liang L, Schmid K, Sandhu N, Angleson JK, Vijayan MM, Dores RM. Structure/function studies on the activation of the rainbow trout melanocortin-2 receptor. Gen Comp Endocrinol 2015; 210:145-51. [PMID: 24709361 DOI: 10.1016/j.ygcen.2014.03.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 03/08/2014] [Accepted: 03/11/2014] [Indexed: 10/25/2022]
Abstract
Functional expression of the rainbow trout (rt) melanocortin-2 receptor (MC2R) in CHO cells requires co-expression with a teleost melanocortin-2 receptor accessory protein (MRAP) such as zebrafish (zf) MRAP. Transiently transfected rtMC2R/zfMRAP1 CHO cells were used to evaluate the efficacy of alanine substituted analogs of hACTH(1-24) in three motifs in the ligand: H(6)F(7)R(8)W(9), G(10)K(11)P(12)V(13)G(14), and K(15)K(16)R(17)R(18)P(19). Alanine substitution at all positions in each motif either completely blocked activation of the receptor (H(6)F(7)R(8)W(9) and K(15)K(16)R(17)R(18)P(19)) or resulted in just over 400 fold increase in EC50 value (G(10)K(11)P(12)V(13)G(14)). Single alanine substitutions in the H(6)F(7)R(8)W(9) motif indicated that substitution at either W(9) or R(8) resulted in a much larger increase in EC50 values as compared to substitutions at either F(7) or W(9). Alanine substitution at either K(15)K(16) or R(17)R(18)P(19) in the K(15)K(16)R(17)R(18)P(19) motif resulted in a statistically equivalent increase in EC50 value of at least 600 fold. Finally, alanine substitutions in the G(10)K(11)P(12)V(13)G(14) motif resulted in increases in EC50 values presumably as a result of altering the secondary structure of the ligand. However, truncated analogs of hACTH(1-24) in which either G(10)G(14) (ACTH(1-22), or K(11)P(12)V(13) (ACTH(1-21) were removed had no stimulatory activity. Finally, some of the hACTH(1-24) analogs were tested using rainbow trout head kidney pieces in vitro to confirm whether the response to analogs seen with the transient transfected rtMC2R CHO cells was similar to that of trout interrenal cells. The results of these alanine substitution analog studies are used to construct a multistep hypothetical model for the activation of teleost and tetrapod MC2Rs to account for the unique ligand selectivity of this receptor.
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Affiliation(s)
- Liang Liang
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Kristin Schmid
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
| | - Navdeep Sandhu
- University of Calgary, Department of Biological Sciences, Calgary, Canada
| | - Joseph K Angleson
- 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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26
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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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27
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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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28
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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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29
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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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30
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Takahashi A, Kobayashi Y, Mizusawa K. The pituitary-interrenal axis of fish: a review focusing on the lamprey and flounder. Gen Comp Endocrinol 2013; 188:54-9. [PMID: 23524003 DOI: 10.1016/j.ygcen.2013.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 02/28/2013] [Accepted: 03/04/2013] [Indexed: 01/12/2023]
Abstract
In fish, the pituitary-interrenal axis is associated with stress response and a variety of biological processes such as metabolism, immune response, and growth. The major hormones involved in this axis are adrenocorticotropic hormone (ACTH), released from the pars distalis of the pituitary gland, and corticosteroid, released from the interrenal gland that is embedded in the head kidney in ray-finned fish. The ACTH signal, by which corticosteroid release is stimulated, is transmitted by melanocortin (MC) receptors on interrenal cells. Thus, the interaction of ACTH and MC receptors is the pivotal event for interrenal cells. Knowledge about ACTH and MC receptors in lamprey, cartilaginous fish, and ray-finned fish is available, and it suggests the pituitary-interrenal axis was established early in vertebrate evolution. Moreover, the data, including our recent results from flounders and lampreys, provide interesting features about ligand-receptor interactions. This review focuses on the characteristics of ACTH, the proopiomelanocortin gene encoding ACTH, and the MC receptor, and it is mostly based on the results of our investigations.
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Affiliation(s)
- Akiyoshi Takahashi
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
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31
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Davis P, Franquemont S, Liang L, Angleson JK, Dores RM. Evolution of the melanocortin-2 receptor in tetrapods: studies on Xenopus tropicalis MC2R and Anolis carolinensis MC2R. Gen Comp Endocrinol 2013; 188:75-84. [PMID: 23639234 DOI: 10.1016/j.ygcen.2013.04.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 04/05/2013] [Accepted: 04/06/2013] [Indexed: 12/25/2022]
Abstract
The tetrapods are a diverse assemblage of vertebrates, and that diversity is reflected in the sequences of tetrapod melanocortin-2 receptors (MC2Rs). In this review, the features common to human (mammal), Gallus gallus (bird), Anolis carolinensis (reptile), and Xenopus tropicalis (amphibian) MC2Rs in terms of ligand selectivity, requirements for interaction with MRAP1, and the effects of alanine substitutions to three amino acid motifs in the ligand hACTH(1-24) are discussed. Analysis of the effects of alanine substitutions to the H(6)F(7)R(8)W(9) and the K(15)K(16)R(17)R(18)P(19) motifs of hACTH(1-24) indicated that activation of A. carolinensis MC2R and X. tropicalis MC2R was more adversely affected by alanine substitutions at these positions as compared to the response of human MC2R to these same analogs. Furthermore, single alanine substitutions in the G(10)K(11)P(12)V(13)G(14) motif of hACTH(1-24) had negative affects on activation of both A. carolinensis MC2R and X. tropicalis MC2R that were not observed for human MC2R. The implications of responses to the various analogs of hACTH(1-24) in terms of the mechanism for mediating the activation of these various tetrapod melanocortin-2 receptors are discussed.
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Affiliation(s)
- Perry Davis
- University of Denver, Department of Biological Sciences, Denver, CO 80210, USA
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32
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Cerdá-Reverter JM, Agulleiro MJ, Cortés R, Sánchez E, Guillot R, Leal E, Fernández-Durán B, Puchol S, Eley M. Involvement of melanocortin receptor accessory proteins (MRAPs) in the function of melanocortin receptors. Gen Comp Endocrinol 2013; 188:133-6. [PMID: 23410915 DOI: 10.1016/j.ygcen.2013.01.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/21/2013] [Accepted: 01/27/2013] [Indexed: 12/30/2022]
Abstract
The melanocortin system integrates different agonists, competitive or inverse agonists, and receptors. Recent investigations have also discovered a specific system of melanocortin receptor accessory proteins (MRAPs) that are involved in the regulation of the functional expression of these receptors. MRAP1 mutations are responsible for type 2 familial glucocorticoid deficiency (FGD2), a rare autosomal disorder characterized by high plasma adrenocorticotropin hormone (ACTH) levels but severe cortisol deficiency. ACTH binds melanocortin 2 receptor (MC2R), a G protein-coupled receptor, in the adrenal gland to promote corticosteroid synthesis. In the absence of MRAP1, MC2R cannot translocate from the endoplasmic reticulum to the plasma membrane and ACTH-induced signaling is extinguished. A second MRAP protein, called MRAP2, also modulates MC2R activity. MRAPs also interact with the other melanocortin receptors, adjusting their pharmacological properties. In this paper, we briefly review the MRAP system and its interaction with melanocortin receptors.
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Affiliation(s)
- J M Cerdá-Reverter
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), 12595 Torre de la Sal, Ribera de Cabanes, Castellón, Spain.
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33
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Agulleiro MJ, Sánchez E, Leal E, Cortés R, Fernández-Durán B, Guillot R, Davis P, Dores RM, Gallo-Payet N, Cerdá-Reverter JM. Molecular characterization and functional regulation of melanocortin 2 receptor (MC2R) in the sea bass. A putative role in the adaptation to stress. PLoS One 2013; 8:e65450. [PMID: 23724142 PMCID: PMC3664627 DOI: 10.1371/journal.pone.0065450] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 04/25/2013] [Indexed: 01/11/2023] Open
Abstract
The activation of melanocortin 2 receptor (MC2R) by ACTH mediates the signaling cascade leading to steroid synthesis in the interrenal tissue (analogous to the adrenal cortex in mammals) of fish. However, little is known about the functional regulation of this receptor in fish. In this work described, we cloned sea bass MC2R from a liver cDNA. SbMC2R requires the melanocortin 2 receptor accessory protein (MRAP) for its functional expression. Dietary cortisol but not long-term stress protocols downregulated interrenal sbMC2R expression. Data suggest the existence of a negative feedback on interrenal sbMC2R expression imposed by local or systemic glucocorticoids. This feedback could be involved in long-term stress adaptation by regulating interrenal sensitivity to ACTH. ACTH-induced MC2R activation stimulates hepatic lipolysis, suggesting that ACTH may mediate stress-induced effects upstream of cortisol release.
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MESH Headings
- Adaptation, Biological/genetics
- Adrenocorticotropic Hormone/pharmacology
- Amino Acid Sequence
- Animals
- Bass/genetics
- Bass/metabolism
- CHO Cells
- Cloning, Molecular
- Cricetulus
- Fasting
- Gene Expression
- Gene Expression Regulation/drug effects
- Lipid Metabolism/drug effects
- Liver/drug effects
- Liver/metabolism
- Molecular Sequence Data
- Organ Specificity/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Melanocortin, Type 2/agonists
- Receptor, Melanocortin, Type 2/chemistry
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 2/metabolism
- Sequence Alignment
- Stress, Physiological/genetics
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Affiliation(s)
- Maria Josep Agulleiro
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), 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), Castellón, Spain
| | - Esther Leal
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Castellón, Spain
| | - Raúl Cortés
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Castellón, Spain
| | - Begoña Fernández-Durán
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), 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), Castellón, Spain
| | - Perry Davis
- Department of Biological Sciences, University of Denver, Denver, Colorado, United States of America
| | - Robert M. Dores
- Department of Biological Sciences, University of Denver, Denver, Colorado, United States of America
| | - Nicole Gallo-Payet
- Department of Medicine, University of Sherbrooke, Sherbrooke, Québec, Canada
| | - 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), Castellón, Spain
- * E-mail:
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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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Novoselova TV, Jackson D, Campbell DC, Clark AJL, Chan LF. Melanocortin receptor accessory proteins in adrenal gland physiology and beyond. J Endocrinol 2013; 217:R1-11. [PMID: 23418361 DOI: 10.1530/joe-12-0501] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The melanocortin receptor (MCR) family consists of five G-protein-coupled receptors (MC1R-MC5R) with diverse physiological roles. MC1R controls pigmentation, MC2R is a critical component of the hypothalamic-pituitary-adrenal axis, MC3R and MC4R have a vital role in energy homeostasis and MC5R is involved in exocrine function. The melanocortin receptor accessory protein (MRAP) and its paralogue MRAP2 are small single-pass transmembrane proteins that have been shown to regulate MCR expression and function. In the adrenal gland, MRAP is an essential accessory factor for the functional expression of the MC2R/ACTH receptor. The importance of MRAP in adrenal gland physiology is demonstrated by the clinical condition familial glucocorticoid deficiency, where inactivating MRAP mutations account for ∼20% of cases. MRAP is highly expressed in both the zona fasciculata and the undifferentiated zone. Expression in the undifferentiated zone suggests that MRAP could also be important in adrenal cell differentiation and/or maintenance. In contrast, the role of adrenal MRAP2, which is highly expressed in the foetal gland, is unclear. The expression of MRAPs outside the adrenal gland is suggestive of a wider physiological purpose, beyond MC2R-mediated adrenal steroidogenesis. In vitro, MRAPs have been shown to reduce surface expression and signalling of all the other MCRs (MC1,3,4,5R). MRAP2 is predominantly expressed in the hypothalamus, a site that also expresses a high level of MC3R and MC4R. This raises the intriguing possibility of a CNS role for the MRAPs.
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Affiliation(s)
- T V Novoselova
- Centre for Endocrinology, Queen Mary University of London, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Charterhouse Square, London EC1M6BQ, UK
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