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Kim JH, Lee JE, Kim T, Yeom MH, Park JS, di Luccio E, Chen H, Dong Z, Lee KW, Kang NJ. 7,3',4'-Trihydroxyisoflavone, a Metabolite of the Soy Isoflavone Daidzein, Suppresses α-Melanocyte-Stimulating Hormone-Induced Melanogenesis by Targeting Melanocortin 1 Receptor. Front Mol Biosci 2020; 7:577284. [PMID: 33344501 PMCID: PMC7747307 DOI: 10.3389/fmolb.2020.577284] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/10/2020] [Indexed: 11/13/2022] Open
Abstract
7,3',4'-Trihydroxyisoflavone (7,3',4'-THIF) is a metabolite of daidzein which is a representative isoflavone found in soybean. Recent studies suggested that 7,3',4'-THIF exerts a hypopigmentary effect in B16F10 cells, however, its underlying molecular mechanisms and specific target protein remain unknown. Here, we found that 7,3',4'-THIF, but not daidzein, inhibited α-melanocyte-stimulating hormone (MSH)-induced intracellular and extracellular melanin production in B16F10 cells by directly targeting melanocortin 1 receptor (MC1R). Western blot data showed that 7,3',4'-THIF inhibited α-MSH-induced tyrosinase, tyrosinase-related protein-1 (TYRP-1), and tyrosinase-related protein-2 (TYRP-2) expressions through the inhibition of Microphthalmia-associated transcription factor (MITF) expression and cAMP response element-binding (CREB) phosphorylation. 7,3',4'-THIF also inhibited α-MSH-induced dephosphorylation of AKT and phosphorylation of p38 and cAMP-dependent protein kinase (PKA). cAMP and Pull-down assays indicated that 7,3',4'-THIF strongly inhibited forskolin-induced intracellular cAMP production and bound MC1R directly by competing with α-MSH. Moreover, 7,3',4'-THIF inhibited α-MSH-induced intracellular melanin production in human epidermal melanocytes (HEMs). Collectively, these results demonstrate that 7,3',4'-THIF targets MC1R, resulting in the suppression of melanin production, suggesting a protective role for 7,3',4'-THIF against melanogenesis.
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Affiliation(s)
- Ji Hye Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea.,Korean Medicine Application Center, Korea Institute of Oriental Medicine, Daegu, South Korea
| | - Jae-Eun Lee
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea
| | - Taewon Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea
| | - Myung Hun Yeom
- Amorepacific Corporation R&D Center, Skin Research Institute, Yongin, South Korea
| | - Jun Seong Park
- Amorepacific Corporation R&D Center, Skin Research Institute, Yongin, South Korea
| | - Eric di Luccio
- Department of Genetic Engineering, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu, South Korea
| | - Hanyong Chen
- The Hormel Institute, University of Minnesota, Austin, MN, United States
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, Austin, MN, United States
| | - Ki Won Lee
- World Class University Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.,Advanced Institutes of Convergence Technology, Seoul National University, Suwon, South Korea.,Research Institute of Bio Food Industry, Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, South Korea
| | - Nam Joo Kang
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, South Korea
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Morais M, Zamora-Carreras H, Raposinho PD, Oliveira MC, Pantoja-Uceda D, Correia JDG, Jiménez MA. NMR Insights into the Structure-Function Relationships in the Binding of Melanocortin Analogues to the MC1R Receptor. Molecules 2017; 22:molecules22071189. [PMID: 28714883 PMCID: PMC6152105 DOI: 10.3390/molecules22071189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 01/25/2023] Open
Abstract
Linear and cyclic analogues of the α-melanocyte stimulating hormone (α-MSH) targeting the human melanocortin receptor 1 (MC1R) are of pharmacological interest for detecting and treating melanoma. The central sequence of α-MSH (His-Phe-Arg-Trp) has been identified as being essential for receptor binding. To deepen current knowledge on the molecular basis for α-MSH bioactivity, we aimed to understand the effect of cycle size on receptor binding. To that end, we synthesised two macrocyclic isomeric α-MSH analogues, c[NH-NO2-C6H3-CO-His-DPhe-Arg-Trp-Lys]-Lys-NH2 (CycN-K6) and c[NH-NO2-C6H3-CO-His-DPhe-Arg-Trp-Lys-Lys]-NH2 (CycN-K7). Their affinities to MC1R receptor were determined by competitive binding assays, and their structures were analysed by 1H and 13C NMR. These results were compared to those of the previously reported analogue c[S-NO2-C6H3-CO-His-DPhe-Arg-Trp-Cys]-Lys-NH2 (CycS-C6). The MC1R binding affinity of the 22-membered macrocyclic peptide CycN-K6 (IC50 = 155 ± 16 nM) is higher than that found for the 25-membered macrocyclic analogue CycN-K7 (IC50 = 495 ± 101 nM), which, in turn, is higher than that observed for the 19-membered cyclic analogue CycS-C6 (IC50 = 1770 ± 480 nM). NMR structural study indicated that macrocycle size leads to changes in the relative dispositions of the side chains, particularly in the packing of the Arg side chain relative to the aromatic rings. In contrast to the other analogues, the 22-membered cycle’s side chains are favorably positioned for receptor interaction.
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Affiliation(s)
- Maurício Morais
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Portugal.
- Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, UK.
| | - Héctor Zamora-Carreras
- Instituto de Química Física Rocasolano (IQFR), Consejo Superior de Investigaciones Científicas (CSIC), Serrano 119, 28006 Madrid, Spain.
| | - Paula D Raposinho
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Portugal.
| | - Maria Cristina Oliveira
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Portugal.
| | - David Pantoja-Uceda
- Instituto de Química Física Rocasolano (IQFR), Consejo Superior de Investigaciones Científicas (CSIC), Serrano 119, 28006 Madrid, Spain.
| | - João D G Correia
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066 Bobadela LRS, Portugal.
| | - M Angeles Jiménez
- Instituto de Química Física Rocasolano (IQFR), Consejo Superior de Investigaciones Científicas (CSIC), Serrano 119, 28006 Madrid, Spain.
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Karhu L, Turku A, Xhaard H. Modeling of the OX1R-orexin-A complex suggests two alternative binding modes. BMC STRUCTURAL BIOLOGY 2015; 15:9. [PMID: 25957175 PMCID: PMC4469407 DOI: 10.1186/s12900-015-0036-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/21/2015] [Indexed: 01/25/2023]
Abstract
Background Interactions between the orexin peptides and their cognate OX1 and OX2 receptors remain poorly characterized. Site-directed mutagenesis studies on orexin peptides and receptors have indicated amino acids important for ligand binding and receptor activation. However, a better understanding of specific pairwise interactions would benefit small molecule discovery. Results We constructed a set of three-dimensional models of the orexin 1 receptor based on the 3D-structures of the orexin 2 receptor (released while this manuscript was under review), neurotensin receptor 1 and chemokine receptor CXCR4, conducted an exhaustive docking of orexin-A16–33 peptide fragment with ZDOCK and RDOCK, and analyzed a total of 4301 complexes through multidimensional scaling and clustering. The best docking poses reveal two alternative binding modes, where the C-terminus of the peptide lies deep in the binding pocket, on average about 5–6 Å above Tyr6.48 and close to Gln3.32. The binding modes differ in the about 100° rotation of the peptide; the peptide His26 faces either the receptor’s fifth transmembrane helix or the seventh helix. Both binding modes are well in line with previous mutation studies and partake in hydrogen bonding similar to suvorexant. Conclusions We present two binding modes for orexin-A into orexin 1 receptor, which help rationalize previous results from site-directed mutagenesis studies. The binding modes should serve small molecule discovery, and offer insights into the mechanism of receptor activation. Electronic supplementary material The online version of this article (doi:10.1186/s12900-015-0036-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lasse Karhu
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
| | - Ainoleena Turku
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
| | - Henri Xhaard
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
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Cui S, Wang Y, Chen G. Disturbance of DNA conformation by the binding of testosterone-based platinum drugs via groove-face and intercalative interactions: a molecular dynamics simulation study. BMC STRUCTURAL BIOLOGY 2013; 13:4. [PMID: 23517640 PMCID: PMC3610147 DOI: 10.1186/1472-6807-13-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 03/14/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND To explore novel platinum-based anticancer agents that are distinct from the structure and interaction mode of the traditional cisplatin by forming the bifunctional intrastrand 1,2 GpG adduct, the monofunctional platinum+DNA adducts with extensive non-covalent interactions had been studied. It was reported that the monofunctional testosterone-based platinum(II) agents present the high anticancer activity. Moreover, it was also found that the testosterone-based platinum agents could cause the DNA helix to undergo significant unwinding and bending over the non-testosterone-based platinum agents. However, the interaction mechanisms of these platinum agents with DNA at the atomic level are not yet clear so far. RESULTS In the present work, we used molecular dynamics (MD) simulations and DNA conformational dynamics calculations to study the DNA distortion properties of the testosterone-based platinum+DNA, the improved testosterone-based platinum+DNA and the non-testosterone-based platinum+DNA adducts. The results show that the intercalative interaction of the improved flexible testosterone-based platinum agent with DNA molecule could cause larger DNA conformational distortion than the groove-face interaction of the rigid testosterone-based platinum agent with DNA molecule. Further investigations for the non-testosterone-based platinum agent reveal the occurrence of insignificant change of DNA conformation due to the absence of testosterone ligand in such agent. Based on the DNA dynamics analysis, the DNA base motions relating to DNA groove parameter changes and hydrogen bond destruction of DNA base pairs were also discussed in this work. CONCLUSIONS The flexible linker in the improved testosterone-based platinum agent causes an intercalative interaction with DNA in the improved testosterone-based platinum+DNA adduct, which is different from the groove-face interaction caused by a rigid linker in the testosterone-based platinum agent. The present investigations provide useful information of DNA conformation affected by a testosterone-based platinum complex at the atomic level.
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Affiliation(s)
- Shanshan Cui
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Yan Wang
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
- Present address: College of Chemistry, Beijing Normal University, 19# Xinjiekouwai Street, Haidian District, Beijing 100875, PR China
| | - Guangju Chen
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
- Present address: College of Chemistry, Beijing Normal University, 19# Xinjiekouwai Street, Haidian District, Beijing 100875, PR China
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Ozola A, Azarjana K, Doniņa S, Proboka G, Mandrika I, Petrovska R, Cēma I, Heisele O, Eņģele L, Streinerte B, Pjanova D. Melanoma risk associated with MC1R gene variants in Latvia and the functional analysis of rare variants. Cancer Genet 2013; 206:81-91. [PMID: 23522749 DOI: 10.1016/j.cancergen.2013.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/11/2013] [Accepted: 01/22/2013] [Indexed: 12/30/2022]
Abstract
To evaluate the association of melanocortin 1 receptor gene (MC1R) variants with melanoma risk in a Latvian population, the MC1R gene was sequenced in 200 melanoma patients and 200 control persons. A functional study of previously uncharacterized, rare MC1R variants was also performed. In total, 26 different MC1R variants, including two novel variants Val165Ile and Val188Ile, were detected. The highest risk of melanoma was associated with the Arg151Cys variant (odds ratio (OR) 4.47, 95% confidence interval (CI) 2.19-9.14, P<0.001). A gene dosage effect was observed, with melanoma risk for carriers of two variants being twice (OR 3.98, 95% CI 2.15-7.38, P<0.001) that of carriers of one variant (OR 1.98, 95% CI 1.26-3.11, P=0.003). After stratification according to the pigmentation phenotype, the risk of melanoma remained in groups with otherwise protective phenotypes. Functional analyses of eight previously uncharacterized MC1R variants revealed that a subset of them is functionally relevant. Our results support the contribution of MC1R variants to a genetic predisposition to melanoma in Latvia.
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Affiliation(s)
- Aija Ozola
- Latvian Biomedical Research and Study Centre, Riga, Latvia.
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Fanelli F, De Benedetti PG. Update 1 of: computational modeling approaches to structure-function analysis of G protein-coupled receptors. Chem Rev 2011; 111:PR438-535. [PMID: 22165845 DOI: 10.1021/cr100437t] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy.
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Vidal O, Araguas RM, Fernández E, Heras S, Sanz N, Pla C. Melanism in guinea fowl (Numida meleagris) is associated with a deletion of Phenylalanine-256 in the MC1R gene. Anim Genet 2011; 41:656-8. [PMID: 20477788 DOI: 10.1111/j.1365-2052.2010.02056.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have characterized a deletion in the MC1R gene causing the loss of one amino acid (p.Phe256del), which is perfectly associated with melanism in guinea fowl (Numida meleagris). Co-segregation of the p.Phe256del with melanism was confirmed in 25 offspring born from a cross of two heterozygote birds; therefore we suggest that this mutation is responsible for the black phenotype. Interestingly, this is the first case of recessive melanism linked to MC1R.
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Affiliation(s)
- O Vidal
- Departament de Biologia, Universitat de Girona, Girona, Catalonia, Spain.
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Dessinioti C, Antoniou C, Katsambas A, Stratigos AJ. Melanocortin 1 receptor variants: functional role and pigmentary associations. Photochem Photobiol 2011; 87:978-87. [PMID: 21749400 DOI: 10.1111/j.1751-1097.2011.00970.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The significance of human cutaneous pigmentation lies in its protective role against sun-induced DNA damage and photocarcinogenesis. Fair skin and red hair are characterized by a low eumelanin to pheomelanin ratio, and have been associated with increased risk of skin cancer. Cutaneous pigmentation is a complex genetic trait, with more than 120 genes involved in its regulation, among which the melanocortin 1 receptor gene (MC1R) plays a key role. Although a large number of single nucleotide polymorphisms (SNPs) have been identified in pigmentation genes, very few SNPs have been examined in relation to human pigmentary phenotypes and skin cancer risk. Recent GWAS have identified new candidate determinants of pigmentation traits, but MC1R remains the best characterized genetic determinant of human skin and hair pigmentation as well as the more firmly validated low-penetrance skin cancer susceptibility gene. In this review, we will address how the melanocortin system regulates pigmentation, the effect of MC1R variants on the physiologic function of the MC1 receptor, and how specific MC1R variants are associated with distinct human pigmentation phenotypes.
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Affiliation(s)
- Clio Dessinioti
- 1st Department of Dermatology, University of Athens, Andreas Sygros Hospital, Athens, Greece.
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Eskandani M, Hasannia S, Vandghanooni S, Pirooznia N, Golchai J. ASSESSMENT OF MC1R AND α-MSH GENE SEQUENCES IN IRANIAN VITILIGO PATIENTS. Indian J Dermatol 2011; 55:325-8. [PMID: 21430882 PMCID: PMC3051289 DOI: 10.4103/0019-5154.74530] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background: Vitiligo is an acquired pigmentary disorder of the skin that is caused by unknown factors and is characterized by white and depigmented patches that enlarge and become more numerous with time. Genetic factors, oxidative stress, autoimmunity, and neurochemical agents, such as catecholamines might also contribute to vitiligo. Cutaneous pigmentation is determined by the amounts of eumelanin and pheomelanin synthesized by the epidermal melanocytes and interference of melanocortin-1 receptor (MC1R), a G-protein coupled receptor, its normal agonist, alpha-melanocyte stimulating hormone (α-MSH), and key enzymes, such as tyrosinase, to protect against sun-induced DNA damage. The MC1R, a 7 pass trans-membrane G-protein coupled receptor, is a key control point in melanogenesis. Loss-of-function mutations at the MC1R are associated with a switch from eumelanin to pheomelanin production, resulting in a red or yellow coat color. Aim: In this research, we aim to examine the genetic variety of MC1R and α-MSH gene in 20 Iranian vitiligo patients and 20 healthy controls. Materials and Methods: Analysis of the MC1R coding gene was performed with direct sequencing. Results: We found the following 9 MC1R coding region variants: Arg163Gl (G488A), Arg227Leu (G680A), Val 97Phe (G289T), Asp184Asn (G550A), Arg227Lys (G680A), Arg142His (G425A), Val60Leu (G178T), Val247Met (C739A), and Val174Ile (G520A). We also found 2 frameshift changes: one of them was the Insertion of C (frameshift in Pro136, stop at Trp148) and the other, Insertion of G (frameshift in Pro256, stop at Trp 333). Of all the changes, the most common was Val60Leu at 5% in patients vs 20% in controls, Val247Met at 15% in patients vs 0% in controls and Val174Ile at 15% in controls and 0% in patients. The other variants showed a frequency <5% in both patients and controls. Also in this study, we have examined the frequency of single nucleotide polymorphisms within the α-MSH genes with direct sequencing in 20 patients and 20 healthy subjects but found no changes along this gene. Conclusion: We could not find any relationship between MC1R and α-MSH genes and their effect on the disease in Iranian vitiligo patients.
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Affiliation(s)
- M Eskandani
- The University of Guilan, Guilan, Rasht, Iran
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10
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Yang Y. Structure, function and regulation of the melanocortin receptors. Eur J Pharmacol 2011; 660:125-30. [PMID: 21208602 DOI: 10.1016/j.ejphar.2010.12.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/23/2010] [Accepted: 12/10/2010] [Indexed: 01/30/2023]
Abstract
Melanocortin receptors belong to the seven-transmembrane (TM) domain proteins that are coupled to G-proteins and signaled through intracellular cyclic adenosine monophosphate. Many structural features conserved in other G-protein coupled receptors (GPCRs) are found in the melanocortin receptors. There are five melanocortin receptor subtypes and each of the melanocortin receptor subtypes has a different pattern of tissue expression and has its own profile regarding the relative potency of different melanocortin peptides. α-, β-, and γ-MSH and ACTH are known endogenous agonist ligands for the melanocortin receptors. Agouti and AgRP are the only known naturally occurring antagonists of the melanocortin receptors. We have examined the molecular basis of all five human melanocortin receptors for different ligand binding affinities and potencies using chimeric and mutated receptors. Our studies indicate that human melanocortin MC(1) receptor, human melanocortin MC(3) receptor, human melanocortin MC(4) receptor and human melanocortin MC(5) receptor utilize orthosteric sites for non selective agonists, α-MSH and NDP-α-MSH, high affinity binding and utilize allosteric sites for selective agonist or antagonist binding. Furthermore, our results indicate that molecular determinants of human melanocortin MC(2) receptor for ACTH binding and signaling are different from that of other melanocortin receptors. Many studies also indicate that agonists can induce different conformation changes of melanocortin receptors, which then lead to the activation of different signaling pathways, even when the expression level of receptor and the strength of stimulus-response coupling are the same. This finding may provide new information for the design of drugs for targeting melanocortin receptors.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, 35294, United States.
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11
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Vidal O, Viñas J, Pla C. Variability of the melanocortin 1 receptor (MC1R) gene explains the segregation of the bronze locus in turkey (Meleagris gallopavo). Poult Sci 2010; 89:1599-602. [PMID: 20634512 DOI: 10.3382/ps.2010-00726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
By sequencing the full coding region of the turkey melanocortin 1 receptor (MC1R) gene, we have found 4 mutations (c.96G > A, c.364A > T, c.450C > T, and c.887C > T) that are organized in 5 different haplotypes (MC1R*1 to MC1R*5). These haplotypes correlate perfectly with the 3 alleles of the bronze locus (i.e., B, b(+), and b(1)). We suggest that the dominant black phenotype, associated with the B allele, results from the constitutive activation of the receptor, an effect that might be mediated by the missense mutation c.364A > T (p.Ile122Phe). Moreover, we propose that the recessive black-winged bronze phenotype (linked to b(1)) might be produced by 2 deleterious mutations of MC1R (c.96G > A and c.887C > T). This is an unexpected finding because in mammals, MC1R deleterious polymorphisms are usually related with either red or lighter fur colors.
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Affiliation(s)
- O Vidal
- Departament de Biologia, Universitat de Girona, E-17071 Girona, Catalonia, Spain.
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12
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Miot LDB, Miot HA, Silva MGD, Marques MEA. [Physiopathology of melasma]. An Bras Dermatol 2010; 84:623-35. [PMID: 20191174 DOI: 10.1590/s0365-05962009000600008] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 06/30/2009] [Indexed: 12/13/2022] Open
Abstract
Melasma is a common dermatosis that involves changes in normal skin pigmentation, resulting from the hyperactivity of epidermal melanocytes. The consequent hyperpigmentation is mostly induced by ultraviolet radiation. Clinically, melasma is characterized by light to dark brown macules that usually occur on the face, although they can also affect the cervical and anterior thoracic regions and upper members.Fertile age women and those with intermediate skin phototypes are most likely to develop melasma. Most of its physiopathogenics is not yet fully understood, but there is a relation with genetic and hormonal factors, drugs and cosmetics use, endocrinopathies and sun exposure. The authors discuss the main aspects associated with skin pigmentation and the development of melasma.
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Interactions of the melanocortin-4 receptor with the peptide agonist NDP-MSH. J Mol Biol 2010; 401:433-50. [PMID: 20600126 PMCID: PMC3101337 DOI: 10.1016/j.jmb.2010.06.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 06/14/2010] [Accepted: 06/15/2010] [Indexed: 02/05/2023]
Abstract
Melanocortin-4 receptor (MC4R) has an important regulatory role in energy homeostasis and food intake. Peptide agonists of the MC4R are characterized by the conserved sequence His6-Phe7-Arg8-Trp9, which is crucial for their interaction with the receptor. This investigation utilized the covalent attachment approach to identify receptor residues in close proximity to the bound ligand [Nle4,d-Phe7]melanocyte-stimulating hormone (NDP-MSH), thereby differentiating between residues directly involved in ligand binding and those mutations that compromise ligand binding by inducing conformational changes in the receptor. Also, recent X-ray structures of G-protein-coupled receptors were utilized to refine a model of human MC4R in the active state (R⁎), which was used to generate a better understanding of the binding mode of the ligand NDP-MSH at the atomic level. The mutation of residues in the human MC4R—such as Leu106 of extracellular loop 1, and Asp122, Ile125, and Asp126 of transmembrane (TM) helix 3, His264 (TM6), and Met292 (TM7)—to Cys residues produced definitive indications of proximity to the side chains of residues in the core region of the peptide ligand. Of particular interest was the contact between d-Phe7 on the ligand and Ile125 of TM3 on the MC4R. Additionally, Met292 (TM7) equivalent to Lys(7.45) (Ballesteros numbering scheme) involved in covalently attaching retinal in rhodopsin is shown to be in close proximity to Trp9. For the first time, the interactions between the terminal regions of NDP-MSH and the receptor are described. The amino-terminus appears to be adjacent to a series of hydrophilic residues with novel interactions at Cys196 (TM5) and Asp189 (extracellular loop 2). These interactions are reminiscent of sequential ligand binding exhibited by the β2-adrenergic receptor, with the former interaction being equivalent to the known interaction involving Ser204 of the β2-adrenergic receptor.
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Beaumont KA, Liu YY, Sturm RA. The melanocortin-1 receptor gene polymorphism and association with human skin cancer. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 88:85-153. [PMID: 20374726 DOI: 10.1016/s1877-1173(09)88004-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The melanocortin-1 receptor (MC1R) is a key gene involved in the regulation of melanin synthesis and encodes a G-protein coupled receptor expressed on the surface of the melanocyte in the skin and hair follicles. MC1R activation after ultraviolet radiation exposure results in the production of the dark eumelanin pigment and the tanning process in humans, providing physical protection against DNA damage. The MC1R gene is highly polymorphic in Caucasian populations with a number of MC1R variant alleles associated with red hair, fair skin, freckling, poor tanning, and increased risk of melanoma and nonmelanoma skin cancer. Variant receptors have shown alterations in biochemical function, largely due to intracellular retention or impaired G-protein coupling, but retain some signaling ability. The association of MC1R variant alleles with skin cancer risk remains after correction for pigmentation phenotype, indicating regulation of nonpigmentary pathways. Notably, MC1R activation has been linked to DNA repair and may also contribute to the regulation of immune responses.
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Affiliation(s)
- Kimberley A Beaumont
- Melanogenix Group, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia
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15
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Targeting melanocortin receptors: an approach to treat weight disorders and sexual dysfunction. Nat Rev Drug Discov 2008; 7:307-23. [PMID: 18323849 DOI: 10.1038/nrd2331] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The melanocortin system has multifaceted roles in the control of body weight homeostasis, sexual behaviour and autonomic functions, and so targeting this pathway has immense promise for drug discovery across multiple therapeutic areas. In this Review, we first outline the physiological roles of the melanocortin system, then discuss the potential of targeting melanocortin receptors by using MC3 and MC4 agonists for treating weight disorders and sexual dysfunction, and MC4 antagonists to treat anorectic and cachectic conditions. Given the complexity of the melanocortin system, we also highlight the challenges and opportunities for future drug discovery in this area.
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16
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Mazur A, Koehler K, Schuelke M, Skunde M, Ostański M, Huebner A. Familial glucocorticoid deficiency type 1 due to a novel compound heterozygous MC2R mutation. HORMONE RESEARCH 2008; 69:363-8. [PMID: 18504396 DOI: 10.1159/000117393] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 10/17/2007] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Description of the clinical, biochemical and genetic features of a Polish patient with familial glucocorticoid deficiency. METHODS Detailed clinical investigation, hormonal analysis and sequencing of the coding region of the melanocortin 2 receptor (MC2R) gene in this patient. RESULTS We report on a 3-month-old boy with familial glucocorticoid deficiency who presented at the age of 3 months with skin hyperpigmentation, muscle weakness, mild jaundice and constipation. Hormonal analyses revealed high ACTH and TSH serum concentrations, low serum cortisol concentration along with normal blood electrolytes. On hydrocortisone supplementation, the disease symptoms disappeared and the child recovered completely. His physical and mental development progresses normally. Genetic analysis disclosed a novel compound heterozygous MC2R mutation p.Leu46fs and p.Val49Met. CONCLUSION The heterozygous p.Leu46fs mutation adds to the small number of MC2R nonsense mutations and is the first frameshift mutation within the first transmembrane domain of the receptor. According to molecular modeling the Val49Met mutation results in a structural change of the first transmembrane domain and in a potential novel interaction of the transmembrane domains I and VII.
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Affiliation(s)
- Artur Mazur
- Institute of Physiotherapy, University of Rzeszów, Poland
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17
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Bednarek MA, MacNeil T, Tang R, Fong TM, Angeles Cabello M, Maroto M, Teran A. Analogs of α-melanocyte stimulating hormone with high agonist potency and selectivity at human melanocortin receptor 1b: The role of Trp9 in molecular recognition. Biopolymers 2008; 89:401-8. [DOI: 10.1002/bip.20863] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Synthesis and biological activity of novel peptide mimetics as melanocortin receptor agonists. Bioorg Med Chem Lett 2007; 18:1223-8. [PMID: 18078748 DOI: 10.1016/j.bmcl.2007.11.109] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 11/25/2007] [Accepted: 11/28/2007] [Indexed: 11/24/2022]
Abstract
A series of novel peptidomimetic analogs was prepared containing cyclohexyl, phenyl, or heterocyclic groups to ostensibly orient the guanidine or mimic of an arginine in a putative melanocortin receptor ligand pharmacophore. Some binding affinity at the melanocortin receptors MC(3) and MC(4) was noted. In silico docking also indicated that the relative positions of the hydrogen-bonding sites and hydrophobic regions of the compounds are reasonably well matched to the receptor-binding site. This may present a lead entry into a selective series of MC(4)R agonists.
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Lapinsh M, Prusis P, Petrovska R, Uhlén S, Mutule I, Veiksina S, Wikberg JES. Proteochemometric modeling reveals the interaction site for Trp9 modified α-MSH peptides in melanocortin receptors. Proteins 2007; 67:653-60. [PMID: 17357163 DOI: 10.1002/prot.21323] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The interactions of alpha-MSH peptides with melanocortin receptors (MCRs) were located by proteochemometric modeling. Nine alpha-MSH peptide analogues were constructed by exchanging the Trp9 residue in the alpha-MSH core with the natural or artificial amino acids Arg, Asp, Cys, Gly, Leu, Nal, d-Nal, Pro, or d-Trp. The nine peptides created, and alpha-MSH itself, were evaluated for their interactions with the 4 wild-type MC(1,3-5)Rs and 15 multichimeric MCRs, each of the latter being constructed from three sequence segments, each taken from a different wild-type MC(1,3-5)R. The segments of the chimeric MCRs were selected according to the principles of statistical molecular design and were arranged so as to divide the receptors into five parts. By this approach, a set of 19 maximally diverse MC receptor proteins was obtained for which the interaction activity with the 10 peptides were measured by radioligand binding thus creating data for 190 ligand-protein pairs, which were subsequently analyzed by use of proteochemometric modeling. In proteochemometrics, the structural or physicochemical properties of both interaction partners, which represent the complementarity of the interacting entities, are used to create multivariate mathematical descriptions. (Here, physicochemical property descriptors of the receptors' and peptides' amino acids were used). A valid, highly predictive (Q2 = 0.74) and easily interpretable model was then obtained. The model was further validated by its ability to correctly predicting the affinity of alpha-MSH for new point and cassette-mutated MC4/MC1Rs, and it was then used to identify the receptor residues that are important for affording the high affinity and selectivity of alpha-MSH for the MC1R. It was revealed that these residues are located in several quite distant parts of the receptors' transmembrane cavity and must therefore cause their influence at various stages of the dynamic ligand-binding process, such as by affecting the conformation of the ligand at the vicinity of the receptor and taking part in the path of the ligand's entry into its binding pocket. Our study can be used as a template how to create high resolution proteochemometric models when there are a limited number of natural proteins and ligands available.
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Affiliation(s)
- Maris Lapinsh
- Department of Pharmaceutical Biosciences, Uppsala University, SE-751 24, Uppsala, Sweden
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20
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Schiöth HB, Muceniece R, Mutule I, Wikberg JES. New melanocortin 1 receptor binding motif based on the C-terminal sequence of alpha-melanocyte-stimulating hormone. Basic Clin Pharmacol Toxicol 2007; 99:287-93. [PMID: 17040213 DOI: 10.1111/j.1742-7843.2006.pto_459.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The C-terminal tripeptide of the alpha-melanocyte stimulating hormone (alpha-MSH11-13) possesses strong antiinflammatory activity without known cellular target. In order to better understand the structural requirements for function of such motif, we designed, synthesized and tested out Trp- and Tyr-containing analogues of the alpha-MSH11-13. Seven alpha-MSH11-13 analogues were synthesized and characterized for their binding to the melanocortin receptors recombinantly expressed in insect (Sf9) cells, infected with baculovirus carrying corresponding MC receptor DNA. We also tested these analogues on B16-F1 mouse melanoma cells endogenously expressing the MC1 receptor for binding and for ability to increase cAMP levels as well as on COS-7 cells transfected with the human MC receptors. The data indicate that HS401 (Ac-Tyr-Lys-Pro-Val-NH2) and HS402 (Ac-Lys-Pro-Val-Tyr-NH2) selectively bound to the MC1 receptor and stimulated cAMP generation in a concentration dependent way while the other Tyr- and Trp-containing alpha-MSH11-13 analogues neither bound to MC receptors nor stimulated cAMP. We have thus identified new MC receptor binding motif derived from the C-terminal sequence of alpha-MSH. The tetrapeptides have novel properties as the both act via MC-ergic pathways and also carry the anti-inflammatory alpha-MSH11-13 message sequence.
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Affiliation(s)
- Helgi B Schiöth
- Department of Neuroscience, Uppsala University, BMC, Uppsala, Sweden.
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21
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Paiva ACM, Oliveira L, Horn F, Bywater RP, Vriend G. Modeling GPCRs. ERNST SCHERING FOUNDATION SYMPOSIUM PROCEEDINGS 2007:23-47. [PMID: 17703576 DOI: 10.1007/2789_2006_002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Many GPCR models have been built over the years for many different purposes, of which drug-design undoubtedly has been the most frequent one. The release of the structure of bovine rhodopsin in August 2000 enabled us to analyze models built before that period to learn things for the models we build today. We conclude that the GPCR modeling field is riddled with "common knowledge". Several characteristics of the bovine rhodopsin structure came as a big surprise, and had obviously not been predicted, which led to large errors in the models. Some of these surprises, however, could have been predicted if the modelers had more rigidly stuck to the rule that holds for all models, namely that a model should explain all experimental facts, and not just those facts that agree with the modeler's preconceptions.
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Affiliation(s)
- A C M Paiva
- CMBI NCMLS, UMC, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
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22
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Strömbergsson H, Prusis P, Midelfart H, Lapinsh M, Wikberg JES, Komorowski J. Rough set-based proteochemometrics modeling of G-protein-coupled receptor-ligand interactions. Proteins 2006; 63:24-34. [PMID: 16435365 DOI: 10.1002/prot.20777] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
G-Protein-coupled receptors (GPCRs) are among the most important drug targets. Because of a shortage of 3D crystal structures, most of the drug design for GPCRs has been ligand-based. We propose a novel, rough set-based proteochemometric approach to the study of receptor and ligand recognition. The approach is validated on three datasets containing GPCRs. In proteochemometrics, properties of receptors and ligands are used in conjunction and modeled to predict binding affinity. The rough set (RS) rule-based models presented herein consist of minimal decision rules that associate properties of receptors and ligands with high or low binding affinity. The information provided by the rules is then used to develop a mechanistic interpretation of interactions between the ligands and receptors included in the datasets. The first two datasets contained descriptors of melanocortin receptors and peptide ligands. The third set contained descriptors of adrenergic receptors and ligands. All the rule models induced from these datasets have a high predictive quality. An example of a decision rule is "If R1_ligand(Ethyl) and TM helix 2 position 27(Methionine) then Binding(High)." The easily interpretable rule sets are able to identify determinative receptor and ligand parts. For instance, all three models suggest that transmembrane helix 2 is determinative for high and low binding affinity. RS models show that it is possible to use rule-based models to predict ligand-binding affinities. The models may be used to gain a deeper biological understanding of the combinatorial nature of receptor-ligand interactions.
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23
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Prusis P, Uhlén S, Petrovska R, Lapinsh M, Wikberg JES. Prediction of indirect interactions in proteins. BMC Bioinformatics 2006; 7:167. [PMID: 16553946 PMCID: PMC1435945 DOI: 10.1186/1471-2105-7-167] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Accepted: 03/22/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Both direct and indirect interactions determine molecular recognition of ligands by proteins. Indirect interactions can be defined as effects on recognition controlled from distant sites in the proteins, e.g. by changes in protein conformation and mobility, whereas direct interactions occur in close proximity of the protein's amino acids and the ligand. Molecular recognition is traditionally studied using three-dimensional methods, but with such techniques it is difficult to predict the effects caused by mutational changes of amino acids located far away from the ligand-binding site. We recently developed an approach, proteochemometrics, to the study of molecular recognition that models the chemical effects involved in the recognition of ligands by proteins using statistical sampling and mathematical modelling. RESULTS A proteochemometric model was built, based on a statistically designed protein library's (melanocortin receptors') interaction with three peptides and used to predict which amino acids and sequence fragments that are involved in direct and indirect ligand interactions. The model predictions were confirmed by directed mutagenesis. The predicted presumed direct interactions were in good agreement with previous three-dimensional studies of ligand recognition. However, in addition the model could also correctly predict the location of indirect effects on ligand recognition arising from distant sites in the receptors, something that three-dimensional modelling could not afford. CONCLUSION We demonstrate experimentally that proteochemometric modelling can be used with high accuracy to predict the site of origin of direct and indirect effects on ligand recognitions by proteins.
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Affiliation(s)
- Peteris Prusis
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
- Linnaeus Center for Bioinformatics, Uppsala University, Uppsala, Sweden
| | - Staffan Uhlén
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
- Section for Pharmacology, The University of Bergen, Bergen, Norway
| | - Ramona Petrovska
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Maris Lapinsh
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Jarl ES Wikberg
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
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24
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García-Borrón JC, Sánchez-Laorden BL, Jiménez-Cervantes C. Melanocortin-1 receptor structure and functional regulation. ACTA ACUST UNITED AC 2006; 18:393-410. [PMID: 16280005 DOI: 10.1111/j.1600-0749.2005.00278.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The melanogenic actions of the melanocortins are mediated by the melanocortin-1 receptor (MC1R). MC1R is a member of the G-protein-coupled receptors (GPCR) superfamily expressed in cutaneous and hair follicle melanocytes. Activation of MC1R by adrenocorticotrophin or alpha-melanocyte stimulating hormone is positively coupled to the cAMP signaling pathway and leads to a stimulation of melanogenesis and a switch from the synthesis of pheomelanins to the production of eumelanic pigments. The functional behavior of the MC1R agrees with emerging concepts in GPCR signaling including dimerization, coupling to more than one signaling pathway and a high agonist-independent constitutive activity accounting for inverse agonism phenomena. In addition, MC1R displays unique properties such as an unusually high number of natural variants often associated with clearly visible phenotypes and the occurrence of endogenous peptide antagonists. Therefore MC1R is an ideal model to study GPCR function. Here we review our current knowledge of MC1R structure and function, with emphasis on information gathered from the analysis of natural variants. We also discuss recent data on the regulation of MC1R function by paracrine and endocrine factors and by external stimuli such as ultraviolet light.
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Affiliation(s)
- José C García-Borrón
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Murcia, Murcia, Spain.
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25
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Pogozheva ID, Chai BX, Lomize AL, Fong TM, Weinberg DH, Nargund RP, Mulholland MW, Gantz I, Mosberg HI. Interactions of human melanocortin 4 receptor with nonpeptide and peptide agonists. Biochemistry 2005; 44:11329-41. [PMID: 16114870 PMCID: PMC2532597 DOI: 10.1021/bi0501840] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Specific interactions of human melanocortin-4 receptor (hMC4R) with its nonpeptide and peptide agonists were studied using alanine-scanning mutagenesis. The binding affinities and potencies of two synthetic, small-molecule agonists (THIQ, MB243) were strongly affected by substitutions in transmembrane alpha-helices (TM) 2, 3, 6, and 7 (residues Glu(100), Asp(122), Asp(126), Phe(261), His(264), Leu(265), and Leu(288)). In addition, a I129A mutation primarily affected the binding and potency of THIQ, while F262A, W258A, Y268A mutations impaired interactions with MB243. By contrast, binding affinity and potency of the linear peptide agonist NDP-MSH were substantially reduced only in D126A and H264A mutants. Three-dimensional models of receptor-ligand complexes with their agonists were generated by distance-geometry using the experimental, homology-based, and other structural constraints, including interhelical H-bonds and two disulfide bridges (Cys(40)-Cys(279), Cys(271)-Cys(277)) of hMC4R. In the models, all pharmacophore elements of small-molecule agonists are spatially overlapped with the corresponding key residues (His(6), d-Phe(7), Arg(8), and Trp(9)) of the linear peptide: their charged amine groups interact with acidic residues from TM2 and TM3, similar to His(6) and Arg(6) of NDP-MSH; their substituted piperidines mimic Trp(9) of the peptide and interact with TM5 and TM6, while the d-Phe aromatic rings of all three agonists contact with Leu(133), Trp(258), and Phe(261) residues.
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MESH Headings
- Amino Acid Sequence
- Binding Sites
- Cyclic AMP/pharmacology
- Humans
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Peptides/pharmacology
- Piperazines/pharmacology
- Piperidines/pharmacology
- Protein Structure, Secondary
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/chemistry
- Receptor, Melanocortin, Type 4/drug effects
- Receptor, Melanocortin, Type 4/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/drug effects
- Recombinant Proteins/metabolism
- Rhodopsin/chemistry
- Sequence Alignment
- Sequence Homology, Amino Acid
- Transfection
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Affiliation(s)
- Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, USA
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26
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Sánchez-Más J, Sánchez-Laorden BL, Guillo LA, Jiménez-Cervantes C, García-Borrón JC. The melanocortin-1 receptor carboxyl terminal pentapeptide is essential for MC1R function and expression on the cell surface. Peptides 2005; 26:1848-57. [PMID: 15993512 DOI: 10.1016/j.peptides.2004.11.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Accepted: 11/05/2004] [Indexed: 10/25/2022]
Abstract
The pigmentary actions of the melanocortins are mediated by the melanocortin-1 receptor (MC1R), a seven transmembrane domains receptor positively coupled to Gs and the cAMP cascade. In order to define the structure-function relationships of potentially relevant domains in MC1R, particularly its C-terminal cytosolic tail, we generated and analyzed several variants with C-terminal deletions, as well as point mutants in selected residues of the human MC1R. We show that the MC1R C-terminal pentapeptide is essential for proper receptor expression on the plasma membrane, and that residues Thr314, Cys315 and Trp317 are at least partially responsible for this effect.
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Affiliation(s)
- J Sánchez-Más
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Murcia, Apto 4021, 30100 Espinardo, Murcia, Spain
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27
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Fanelli F, De Benedetti PG. Computational Modeling Approaches to Structure−Function Analysis of G Protein-Coupled Receptors. Chem Rev 2005; 105:3297-351. [PMID: 16159154 DOI: 10.1021/cr000095n] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Francesca Fanelli
- Dulbecco Telethon Institute and Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, 41100 Modena, Italy.
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28
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29
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Shacham S, Marantz Y, Bar-Haim S, Kalid O, Warshaviak D, Avisar N, Inbal B, Heifetz A, Fichman M, Topf M, Naor Z, Noiman S, Becker OM. PREDICT modeling and in-silico screening for G-protein coupled receptors. Proteins 2005; 57:51-86. [PMID: 15326594 DOI: 10.1002/prot.20195] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
G-protein coupled receptors (GPCRs) are a major group of drug targets for which only one x-ray structure is known (the nondrugable rhodopsin), limiting the application of structure-based drug discovery to GPCRs. In this paper we present the details of PREDICT, a new algorithmic approach for modeling the 3D structure of GPCRs without relying on homology to rhodopsin. PREDICT, which focuses on the transmembrane domain of GPCRs, starts from the primary sequence of the receptor, simultaneously optimizing multiple 'decoy' conformations of the protein in order to find its most stable structure, culminating in a virtual receptor-ligand complex. In this paper we present a comprehensive analysis of three PREDICT models for the dopamine D2, neurokinin NK1, and neuropeptide Y Y1 receptors. A shorter discussion of the CCR3 receptor model is also included. All models were found to be in good agreement with a large body of experimental data. The quality of the PREDICT models, at least for drug discovery purposes, was evaluated by their successful utilization in in-silico screening. Virtual screening using all three PREDICT models yielded enrichment factors 9-fold to 44-fold better than random screening. Namely, the PREDICT models can be used to identify active small-molecule ligands embedded in large compound libraries with an efficiency comparable to that obtained using crystal structures for non-GPCR targets.
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30
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Ringholm A, Klovins J, Rudzish R, Phillips S, Rees JL, Schiöth HB. Pharmacological characterization of loss of function mutations of the human melanocortin 1 receptor that are associated with red hair. J Invest Dermatol 2004; 123:917-23. [PMID: 15482480 DOI: 10.1111/j.0022-202x.2004.23444.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Variation in skin color is the major host risk factor for melanoma and other forms of skin cancer. Individuals with red hair show an increased ratio of phaeomelanin to eumelanin in both hair and skin. This ratio is regulated by the melanocortin (MC) 1 receptor. There are several common point mutations in the human MC1 receptor that are overrepresented in North European red-heads, and in individuals with pale skin. In order to determine the functional significance of these mutations, we expressed the Asp84Glu, Val92Met, Arg163Gln, and Asp294His variants of the human MC1 receptors in eukaryotic cells and determined their ability to bind alpha-melanocyte stimulating hormone (MSH) peptides and increase intracellular cAMP. The mutants Asp84Glu and Asp294His showed a much lower response to alpha-MSH in cAMP and a slightly impaired ability to bind alpha-MSH, and the Val92Met mutant bound alpha-MSH with 100-fold lower affinity as compared with the wild-type. The Arg163Gln variant, widely found in some Asian populations, reached normal level of cAMP response but had just slightly lower potency for alpha-MSH in binding and second messenger studies. The results provide important pharmacological characterization of common MC1 receptor variants in various world populations.
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Affiliation(s)
- Aneta Ringholm
- Department of Neuroscience, Division of Pharmacology, Uppsala University, Uppsala, Sweden
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31
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Koikov LN, Ebetino FH, Solinsky MG, Cross-Doersen D, Knittel JJ. Analogs of sub-nanomolar hMC1R agonist LK-184 [Ph(CH2)3CO-His-d-Phe-Arg-Trp-NH2]. An additional binding site within the human melanocortin receptor 1? Bioorg Med Chem Lett 2004; 14:3997-4000. [PMID: 15225714 DOI: 10.1016/j.bmcl.2004.05.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 05/19/2004] [Accepted: 05/20/2004] [Indexed: 11/21/2022]
Abstract
Twenty nine analogs of a superpotent MC1R agonist LK-184 (1) were tested at human melanocortin receptors (hMC1, hMC3, and hMC4Rs). All derivatives with the spacer between the N-terminus and the aromatic ring longer or shorter than C(3) were much less potent at hMC1R than 1. Only LK-312 PhCO(CH(2))(3)CO-His-d-Phe-Arg-Trp-NH(2) (3), partially mimicking the pi-system of 1, had an EC(50) of 0.05 nM at hMC1R, which confirms the localization of the pi-binding zone of the receptor. Truncation of 1 to Ph(CH(2))(3)CO-His-d-Phe-Arg-NH(2) gave a full MC1 agonist, LK-394 (30), with an EC(50) of 5 nM and a weak partial agonism at MC3/4Rs. This suggests the existence of an additional binding site within hMC1R next to that for the core sequence His-d-Phe-Arg-Trp-NH(2).
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Affiliation(s)
- L N Koikov
- College of Pharmacy, University of Cincinnati, Cincinnati, OH 45267, USA.
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32
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Oliveira L, Hulsen T, Lutje Hulsik D, Paiva ACM, Vriend G. Heavier-than-air flying machines are impossible. FEBS Lett 2004; 564:269-73. [PMID: 15111108 DOI: 10.1016/s0014-5793(04)00320-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Accepted: 02/23/2004] [Indexed: 02/08/2023]
Abstract
Many G protein-coupled receptor (GPCR) models have been built over the years. The release of the structure of bovine rhodopsin in August 2000 enabled us to analyze models built before that period to learn more about the models we build today. We conclude that the GPCR modelling field is riddled with 'common knowledge' similar to Lord Kelvin's remark in 1895 that "heavier-than-air flying machines are impossible", and we summarize what we think are the (im)possibilities of modelling GPCRs using the coordinates of bovine rhodopsin as a template. Associated WWW pages: www.gpcr.org/articles/2003_mod
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Affiliation(s)
- L Oliveira
- Escola Paulista de Medicina, Sao Paulo, Brazil
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33
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Lagerström MC, Klovins J, Fredriksson R, Fridmanis D, Haitina T, Ling MK, Berglund MM, Schiöth HB. High affinity agonistic metal ion binding sites within the melanocortin 4 receptor illustrate conformational change of transmembrane region 3. J Biol Chem 2003; 278:51521-6. [PMID: 14523020 DOI: 10.1074/jbc.m307683200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We created a molecular model of the human melanocortin 4 receptor (MC4R) and introduced a series of His residues into the receptor protein to form metal ion binding sites. We were able to insert micromolar affinity binding sites for zinc between transmembrane region (TM) 2 and TM3 where the metal ion alone was able to activate this peptide binding G-protein-coupled receptor. The exact conformation of the metal ion interactions allowed us to predict the orientation of the helices, and remodeling of the receptor protein indicated that Glu100 and Ile104 in TM2 and Asp122 and Ile125 in TM3 are directed toward a putative area of activation of the receptor. The molecular model suggests that a rotation of TM3 may be important for activation of the MC4R. Previous models of G-protein-coupled receptors have suggested that unlocking of a stabilizing interaction between the DRY motif, in the cytosolic part of TM3, and TM6 is important for the activation process. We suggest that this unlocking process may be facilitated through creation of a new interaction between TM3 and TM2 in the MC4R.
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Affiliation(s)
- Malin C Lagerström
- Department of Neuroscience, Uppsala University, BMC, Box 593, 751 24, Uppsala, Sweden
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34
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Getting SJ, Schiöth HB, Perretti M. Dissection of the anti-inflammatory effect of the core and C-terminal (KPV) alpha-melanocyte-stimulating hormone peptides. J Pharmacol Exp Ther 2003; 306:631-7. [PMID: 12750433 DOI: 10.1124/jpet.103.051623] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we analyzed the anti-inflammatory effects of alpha-melanocyte stimulating hormone (MSH)11-13 (KPV) in comparison with other MSH peptides in a model of crystal-induced peritonitis. Systemic treatment of mice with KPV, alpha-MSH, the core melanocortin peptide His-Phe-Arg-Trp, and the melanocontin receptor 3/4 agonist Ac-Nle4-c[Asp5,d-Phe7,Lys10]NH2 ACTH4-10 (MTII) but not the selective MC1-R agonist H-Ser-Ser-Ile-Ile-Ser-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2 (MS05) resulted in a significant reduction in accumulation of polymorphonuclear leukocyte in the peritoneal cavity. The antimigratory effect of KPV was not blocked by the MC3/4-R antagonist Ac-Nle4-c[Asp5,d-2Nal7,Lys10]NH2 ACTH4-10 (SHU9119). In vitro, macrophage activation, determined as release of KC and interleukin (IL)-1beta was inhibited by alpha-MSH and MTII but not by KPV. Furthermore, macrophage activation by MTII led to an increase in cAMP accumulation, which was attenuated by SHU9119, whereas KPV failed to increase cAMP. The anti-inflammatory properties of KPV were also evident in IL-1beta-induced peritonitis inflammation and in mice with a nonfunctional MC1-R (recessive yellow e/e mice). In conclusion, these data highlight that the C-terminal MSH peptide KPV exhibits an anti-inflammatory effect that is clearly different from that of the core MSH peptides. KPV is unlikely to mediate its effects through melanocortin receptors but is more likely to act through inhibition of IL-1beta functions.
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35
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Lapinsh M, Prusis P, Mutule I, Mutulis F, Wikberg JES. QSAR and proteo-chemometric analysis of the interaction of a series of organic compounds with melanocortin receptor subtypes. J Med Chem 2003; 46:2572-9. [PMID: 12801221 DOI: 10.1021/jm020945m] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have created quantitative structure-activity relationship (QSAR) models describing the interaction of a series of 54 organic compounds with four melanocortin (MC) receptor subtypes, MC(1), MC(3), MC(4), and MC(5). In addition to traditional QSAR analysis, we applied our recently developed proteo-chemometrics approach. Proteo-chemometrics is based on the combined analysis of series of receptors and ligands, wherein descriptions of ligands, proteins, and so-called ligand-protein cross-terms are correlated with interaction activities. The compounds were characterized by structural descriptors, including three-dimensional grid-independent descriptors (GRINDs), topological descriptors, and geometrical descriptors. Description of receptors was obtained by computing the receptors' amino acid sequence identities. Both the QSAR and proteo-chemometrics approaches resulted in models with essentially the same statistical significance: the cross-validated correlation coefficient q(2) for the proteo-chemometric model being 0.71, while for the QSAR models the q(2)s were 0.75, 0.68, 0.63, and 0.71 for the MC(1), MC(3)(-)(5) receptor, respectively. However, the proteo-chemometrics modeling provided more detailed information about receptor-ligand interactions and determinants for receptor subtype selectivity than did QSAR.
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Affiliation(s)
- Maris Lapinsh
- Department of Pharmaceutical Biosciences, Uppsala University, Box 591 BMC, SE751 24 Uppsala, Sweden
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36
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Wikberg JES, Mutulis F, Mutule I, Veiksina S, Lapinsh M, Petrovska R, Prusis P. Melanocortin receptors: ligands and proteochemometrics modeling. Ann N Y Acad Sci 2003; 994:21-6. [PMID: 12851294 DOI: 10.1111/j.1749-6632.2003.tb03158.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The melanocortin receptors exist in five subtypes, MC(1-5)R. These receptors participate in important regulations of the immune system, central behavior, and endocrine and exocrine glands. Here we provide a short review on MCR subtype selective peptides and organic compounds with activity on the MCRs, developed in our laboratory. Also provided is an overview of our new proteochemometric modeling technology, which has been applied to model the interaction of MSH peptides with the MCRs.
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Affiliation(s)
- J E S Wikberg
- Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-751 24 Uppsala, Sweden.
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37
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Millhauser GL, McNulty JC, Jackson PJ, Thompson DA, Barsh GS, Gantz I. Loops and links: structural insights into the remarkable function of the agouti-related protein. Ann N Y Acad Sci 2003; 994:27-35. [PMID: 12851295 DOI: 10.1111/j.1749-6632.2003.tb03159.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The agouti-related protein (AGRP) is an endogenous antagonist of the melanocortin receptors MC3R and MC4R found in the hypothalamus and exhibits potent orexigenic activity. The cysteine-rich C-terminal domain of this protein, corresponding to AGRP(87-132), exhibits receptor binding affinity and antagonism equivalent to that of the full-length protein. We recently determined the NMR structure of AGRP(87-132) and demonstrated that a portion of the domain adopts the inhibitor cystine-knot fold. Remarkably, this is the first identification of a mammalian protein with this specific architecture. Further analysis of the structure suggests that melanocortin receptor contacts are made primarily by two loops presented within the cystine knot. (10) To test this hypothesis we designed a 34-residue AGRP analogue corresponding to only the cystine knot. We found that this designed miniprotein folds to a homogeneous product, retains the desired cystine-knot architecture, functions as a potent antagonist, and maintains the melanocortin receptor pharmacological profile of AGRP(87-132). (26) The AGRP-like activity of this molecule supports the hypothesis that indeed the cystine-knot region possesses the melanocortin receptor contacts. Based on these design and structure studies, we propose that the N-terminal loop of AGRP(87-132) makes contact with a receptor exoloop and helps confer AGRP's selectivity for the central MCRs.
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Affiliation(s)
- Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
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38
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Yang X, Wang Z, Dong W, Ling L, Yang H, Chen R. Modeling and docking of the three-dimensional structure of the human melanocortin 4 receptor. JOURNAL OF PROTEIN CHEMISTRY 2003; 22:335-44. [PMID: 13678297 DOI: 10.1023/a:1025386022852] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A three-dimensional structure of the human melanocortin 4 receptor (hMC4R) is constructed in this study using a computer-aided molecular modeling approach. Human melanocortin 4 receptor is a G Protein-Coupled Receptor (GPCR). We structurally aligned transmembrane helices with bovine rhodopsin transmembrane domains, simulated both intracellular and extracellular loop domains on homologous loop regions in other proteins of known 3D structure and modeled the C terminus on the corresponding part of bovine rhodopsin. Then tandem minimization and dynamics calculations were run to refine the crude structure. The simulative model was tested by docking with a triplet peptide (RFF) ligand. It was found that the ligand is located among transmembrane regions TM3, TM4, TM5, and TM6 of hMC4R. In consistence with mutational and biochemical data, binding site is mainly formed as a hydrophobic and negatively charged pocket. The model constructed here might provide a structural framework for making rational predictions in relevant fields.
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Affiliation(s)
- Xiaonan Yang
- Laboratory of Bioinformatics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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39
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Ringholm A, Klovins J, Fredriksson R, Poliakova N, Larson ET, Kukkonen JP, Larhammar D, Schiöth HB. Presence of melanocortin (MC4) receptor in spiny dogfish suggests an ancient vertebrate origin of central melanocortin system. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:213-21. [PMID: 12605672 DOI: 10.1046/j.1432-1033.2003.03371.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report the cloning, expression, pharmacological characterization and tissue distribution of a melanocortin (MC) receptor gene in a shark, the spiny dogfish (Squalus acanthias) (Sac). Phylogenetic analysis showed that this receptor is an ortholog of the MC4 subtype, sharing 71% overall amino acid identity with the human (Hsa) MC4 receptor. When expressed and characterized by radioligand binding assay for the natural MSH (melanocyte-stimulating hormone) peptides alpha-, beta-, and gamma-MSH, the SacMC4 receptor showed pharmacological properties very similar to the HsaMC4 receptor. Stimulation of SacMC4 receptor transfected cells with alpha-MSH caused a dose-dependent increase in intracellular cAMP levels. The SacMC4 receptor has Ala in position 59 where all other cloned MC receptors have Glu. We confirmed that this was not due to individual polymorphism and subsequently mutated the residue 'back' to Glu but the mutation did not affect the pharmacological properties of the receptor. SacMC4 receptor mRNA was detected by RT-PCR in the optic tectum, hypothalamus, brain stem, telencephalon and olfactory bulb but not in cerebellum or in peripheral tissues. This study describes the first characterization of an MC receptor in a cartilaginous fish, the most distant MC receptor gene cloned to date. Conservation of gene structure, pharmacological properties and tissue distribution suggests that this receptor may have similar roles in sharks as in mammals and that these were established more than 450 million years ago.
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Affiliation(s)
- Aneta Ringholm
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
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40
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Schiöth HB, Tesfaye A, Mutulis F, Rudzish R, Mutule I, Muceniece R, Watanobe H, Wikberg JES. Subtype selective binding properties of substituted linear melanocyte stimulating hormone analogues. Neuropeptides 2002; 36:427-34. [PMID: 12507437 DOI: 10.1016/s0143-4179(02)00133-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The melanocortin receptors are peptide binding G-protein coupled receptors that play a role in important physiological functions such as energy balance, inflammatory processes and several aspects of reproduction. In this study, we synthesised 11 new linear MSH analogues and tested their binding to the human MC receptors (MC1, MC3, MC4 and MC5) expressed in COS cells. Our results show that introduction of Asp in position 4 similarly affects the binding to the MC1, MC4 and MC5 receptors, but drastically lowers the binding to the MC3 receptor. Arg(5) substitution shows relatively high affinity for the MC4 receptor, while the results also give further support for specific importance of His(6) for the MC1 receptor. Introduction of Asp in position 10, mimicking gamma-MSH, decreased the affinity for the MC3 receptor in similar manner as for the MC4 receptor, suggesting that there are important differences in the binding conformation of gamma-MSH and NPD-MSH. Our results provide further information about the ligand binding requirements for each of the MC receptor subtypes, and highlights differential influence of the core residues in the MSH peptides. The data set also provides useful information for further calculations and modeling of MC receptor binders.
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Affiliation(s)
- Helgi B Schiöth
- Department of Neuroscience, Biomedical Center, Uppsala University, Box 593, Uppsala 751 24, Sweden.
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41
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Sánchez Más J, Olivares Sánchez C, Ghanem G, Haycock J, Lozano Teruel JA, García-Borrón JC, Jiménez-Cervantes C. Loss-of-function variants of the human melanocortin-1 receptor gene in melanoma cells define structural determinants of receptor function. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:6133-41. [PMID: 12473109 DOI: 10.1046/j.1432-1033.2002.03329.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The alpha-melanocyte-stimulating hormone (alphaMSH) receptor (MC1R) is a major determinant of mammalian skin and hair pigmentation. Binding of alphaMSH to MC1R in human melanocytes stimulates cell proliferation and synthesis of photoprotective eumelanin pigments. Certain MC1R alleles have been associated with increased risk of melanoma. This can be theoretically considered on two grounds. First, gain-of-function mutations may stimulate proliferation, thus promoting dysplastic lesions. Second, and opposite, loss-of-function mutations may decrease eumelanin contents, and impair protection against the carcinogenic effects of UV light, thus predisposing to skin cancers. To test these possibilities, we sequenced the MC1R gene from seven human melanoma cell (HMC) lines and three giant congenital nevus cell (GCNC) cultures. Four HMC lines and two GCNC cultures contained MC1R allelic variants. These were the known loss-of-function Arg142His and Arg151Cys alleles and a new variant, Leu93Arg. Moreover, impaired response to a superpotent alphaMSH analog was demonstrated for the cell line carrying the Leu93Arg allele and for a HMC line homozygous for wild-type MC1R. Functional analysis in heterologous cells stably or transiently expressing this variant demonstrated that Leu93Arg is a loss-of-function mutation abolishing agonist binding. These results, together with site-directed mutagenesis of the vicinal Glu94, demonstrate that the MC1R second transmembrane fragment is critical for agonist binding and maintenance of a resting conformation, whereas the second intracellular loop is essential for coupling to the cAMP system. Therefore, loss-of-function, but not activating MC1R mutations are common in HMC. Their study provides important clues to understand MC1R structure-function relationships.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Animals
- Arginine/chemistry
- Blotting, Western
- CHO Cells
- Cell Line
- Cell Membrane/metabolism
- Cells, Cultured
- Cloning, Molecular
- Cricetinae
- Cyclic AMP/metabolism
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Heterozygote
- Homozygote
- Humans
- Leucine/chemistry
- Melanoma/genetics
- Melanoma/metabolism
- Mice
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Mutation
- Protein Conformation
- Protein Structure, Tertiary
- Receptors, Corticotropin/genetics
- Receptors, Corticotropin/physiology
- Receptors, Melanocortin
- Sequence Homology, Amino Acid
- Structure-Activity Relationship
- Tumor Cells, Cultured
- Ultraviolet Rays
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Affiliation(s)
- Jesús Sánchez Más
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Murcia, Spain
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42
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Ringholm A, Fredriksson R, Poliakova N, Yan YL, Postlethwait JH, Larhammar D, Schiöth HB. One melanocortin 4 and two melanocortin 5 receptors from zebrafish show remarkable conservation in structure and pharmacology. J Neurochem 2002; 82:6-18. [PMID: 12091460 DOI: 10.1046/j.1471-4159.2002.00934.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We report the cloning, genome mapping, functional expression, pharmacology and anatomical distribution of three melanocortin (MC) receptors from zebrafish (z). Phylogenetic analysis showed with high bootstrap support that these genes represent one MC4 receptor and two MC5 receptors. Chromosomal mapping showed conserved synteny between regions containing zMC4 and human (h) MC4 receptors, whereas the two zMC5 receptor genes map on chromosome segments in which the zebrafish has several genes with two orthologues of a single mammalian gene. It is likely that the two copies of zMC5 receptors arose through a separate duplication in the teleost lineage. The zMC4, zMC5a, and zMC5b receptors share 70-71% overall amino acid identity with the respective human orthologues and over 90% in three TM regions believed to be most important for ligand binding. All three zebrafish receptors also show pharmacological properties remarkably similar to their human orthologues, with similar affinities and the same potency order, when expressed and characterized in radioligand binding assay for the natural MSH) peptides alpha-, beta-, and gamma-MSH. Stimulation of transfected mammalian cells with alpha-MSH caused a dose-dependent increase in intracellular cAMP levels for all three zebrafish receptors. All three genes were expressed in the brain, eye, ovaries and gastrointestinal tract, whereas the zMC5b receptor was also found in the heart, as determined by RT-PCR. Our studies, which represent the first characterization of MC receptors in a nonamniote species, indicate that the MC receptor subtypes arose very early in vertebrate evolution. Important pharmacological and functional properties, as well as gene structure and syntenic relationships have been highly conserved over a period of more than 400 million years implying that these receptors participate in vital physiological functions.
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MESH Headings
- Animals
- Binding, Competitive
- Biological Assay
- Blotting, Southern
- Cell Line
- Chromosome Mapping
- Cloning, Molecular
- Conserved Sequence
- Humans
- Ligands
- Molecular Sequence Data
- Organ Specificity
- Phylogeny
- Radioligand Assay
- Receptor, Melanocortin, Type 4
- Receptors, Corticotropin/biosynthesis
- Receptors, Corticotropin/chemistry
- Receptors, Corticotropin/genetics
- Receptors, Melanocortin
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Zebrafish
- Zebrafish Proteins/biosynthesis
- Zebrafish Proteins/chemistry
- Zebrafish Proteins/genetics
- alpha-MSH/analogs & derivatives
- alpha-MSH/pharmacokinetics
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Affiliation(s)
- Aneta Ringholm
- Department of Neuroscience, Unit of Pharmacology, Uppsala University, BMC, 75 124 Uppsala, Sweden
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43
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Scott MC, Wakamatsu K, Ito S, Kadekaro AL, Kobayashi N, Groden J, Kavanagh R, Takakuwa T, Virador V, Hearing VJ, Abdel-Malek ZA. Humanmelanocortin 1 receptorvariants, receptor function and melanocyte response to UV radiation. J Cell Sci 2002; 115:2349-55. [PMID: 12006619 DOI: 10.1242/jcs.115.11.2349] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cutaneous pigmentation is determined by the amounts of eumelanin and pheomelanin synthesized by epidermal melanocytes and is known to protect against sun-induced DNA damage. The synthesis of eumelanin is stimulated by the binding of α-melanotropin (α-melanocyte-stimulating hormone)to the functional melanocortin 1 receptor (MC1R) expressed on melanocytes. The human MC1R gene is highly polymorphic and certain allelic variants of the gene are associated with red hair phenotype, melanoma and non-melanoma skin cancer. The importance of the MC1R gene in determining skin cancer risk led us to examine the impact of specific polymorphisms in this gene on the responses of human melanocytes to α-melanotropin and UV radiation. We compared the ability of human melanocyte cultures, each derived from a single donor, to respond to α-melanotropin with dose-dependent stimulation of cAMP formation, tyrosinase activity and proliferation. In each of those cultures the MC1R gene was sequenced, and the eumelanin and pheomelanin contents were determined. Human melanocytes homozygous for Arg160Trp, heterozygous for Arg160Trp and Asp294His, or for Arg151Cys and Asp294His substitutions, but not melanocytes homozygous for Val92Met substitution, in the MC1R demonstrated a significantly reduced response toα-melanotropin. Additionally, melanocytes with a non-functional MC1R demonstrated a pronounced increase in their sensitivity to the cytotoxic effect of UV radiation compared with melanocytes expressing functional MC1R. We conclude that loss-of-function mutations in the MC1R gene sensitize human melanocytes to the DNA damaging effects of UV radiation, which may increase skin cancer risk.
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Affiliation(s)
- M Cathy Scott
- Department of Dermatology, University of Cincinnati College of Medicine, PO Box 670592, Cincinnati, Ohio 45267-0592, USA
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Jiménez-Cervantes C, Germer S, González P, Sánchez J, Sánchez CO, García-Borrón JC. Thr40 and Met122 are new partial loss-of-function natural mutations of the human melanocortin 1 receptor. FEBS Lett 2001; 508:44-8. [PMID: 11707265 DOI: 10.1016/s0014-5793(01)03025-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Activation by melanocortins of the melanocortin 1 receptor (MC1R), expressed in epidermal melanocytes, stimulates melanogenesis. Human MC1R gene loss-of-function mutations are associated with fair skin, poor tanning and increased skin cancer risk. We identified two natural alleles: Ile40Thr, probably associated with skin types I-II, and Val122Met. Val122Met bound [(125)I][Nle(4), D-Phe(7)]-alpha-melanocyte stimulating hormone with lower affinity than the wild-type. Dose-response curves of cAMP accumulation were right-shifted for both forms. The Val122Met form failed to achieve maximal cAMP responses comparable to the wild-type or Ile40Thr receptors. Thus, the Ile40Thr and Val122Met variants are partial loss-of-function natural mutations of MC1R.
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Affiliation(s)
- C Jiménez-Cervantes
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Murcia, Apto 4021, 30100 Espinardo, Murcia, Spain.
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45
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Mandrika I, Muceniece R, Wikberg JE. Effects of melanocortin peptides on lipopolysaccharide/interferon-gamma-induced NF-kappaB DNA binding and nitric oxide production in macrophage-like RAW 264.7 cells: evidence for dual mechanisms of action. Biochem Pharmacol 2001; 61:613-21. [PMID: 11239505 DOI: 10.1016/s0006-2952(00)00583-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The pro-opiomelanocortin-derived peptide alpha-melanocyte-stimulating hormone (alpha-MSH) mediates broad anti-inflammatory and immunomodulatory effects, which include inhibition of the production and release of proinflammatory cytokines and nitric oxide (NO) from macrophages. We investigated the effects of alpha-MSH, alpha-MSH(1-10), and alpha-MSH(11-13) on NO production and nuclear factor-kappaB (NF-kappaB) translocation in RAW 264.7 macrophages. After stimulation of the cells with bacterial lipopolysaccharide/interferon-gamma (LPS/IFN-gamma), all three peptides inhibited NO production with an order of potency alpha-MSH > or = alpha-MSH(11-13) > alpha-MSH(1-10). All three MSH peptides inhibited NF-kappaB nuclear translocation with the maximal effect of alpha-MSH and alpha-MSH(11-13) being seen in the range 1 nM-1 microM, and that of alpha-MSH(1-10) at 1 microM. By use of (125)I-(Nle(4),D-Phe(7))alpha-MSH(NDP-MSH) radioligand binding, MC(1) receptor-binding sites were demonstrated on RAW 264.7 cells. alpha-MSH and alpha-MSH(1-10) competed with the (125)I-NDP-MSH binding at these MC(1) receptor-binding sites, but alpha-MSH(11-13) even in concentrations up to 1 mM did not. Moreover, alpha-MSH and alpha-MSH(1-10) caused powerful stimulation of cyclic 3',5'-adenosine monophosphate (cAMP) in the RAW 264.7 cell, whereas alpha-MSH(11-13) was ineffective. Forskolin stimulated cAMP and inhibited NO production to the same extent as alpha-MSH and alpha-MSH(1-10), but did not modify the translocation of NF-kappaB. Whereas the protein kinase A inhibitor H89 did not modify the effect of alpha-MSH on NF-kappaB translocation, H89 caused a partial inhibition of the inhibitory effect of alpha-MSH, alpha-MSH(1-10), alpha-MSH(11-13), and forskolin on NO production. In addition alpha-MSH, alpha-MSH(1-10), alpha-MSH(11-13), and forskolin also inhibited the activity of an NF-kappaB-dependent luciferase reporter and these effects were partially counteracted by H89. We suggest that melanocortin peptides act via dual mechanisms of action: one cAMP-independent and causing inhibition of NF-kappaB translocation and the other dependent on MC(1) receptor/cAMP activation.
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Affiliation(s)
- I Mandrika
- Department of Pharmaceutical Pharmacology, Uppsala University, Box 591, BMC, SE-75124, Uppsala, Sweden
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46
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Muceniece R, Mutule I, Mutulis F, Prusis P, Szardenings M, Wikberg JE. Detection of regions in the MC1 receptor of importance for the selectivity of the MC1 receptor super-selective MS04/MS05 peptides. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1544:278-82. [PMID: 11341936 DOI: 10.1016/s0167-4838(00)00227-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We have investigated the ability of our earlier identified MS04-MS05 MSH-peptide analogues to bind to chimeric MC1-MC3 receptors. While the MS04 and MS05 peptides bind with nanomolar and sub-nanomolar affinities to the wild type MC1 receptor, they bind only with micromolar affinities for the wild type MC3 receptor, thus being the hitherto most MC1 receptor selective ligands. Upon exchanging portions involving transmembrane regions TM1, TM2-3, and TM6-7 of the MC1 receptor with corresponding portions of the MC3 receptor both of these peptides showed major losses of affinities. By contrast exchanges involving TM4-5 did not appreciably affect the affinity of either MS04 or MS05. Our data suggest that the binding pocket for the MS04-MS05 MSH-peptides is located between TM1-3 and TM6-7 of the melanocortin receptors.
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Affiliation(s)
- R Muceniece
- Department of Pharmaceutical Pharmacology, Box 591, BMC, Uppsala University, SE-751 24, Uppsala, Sweden
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47
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Prusis P, Muceniece R, Andersson P, Post C, Lundstedt T, Wikberg JE. PLS modeling of chimeric MS04/MSH-peptide and MC1/MC3-receptor interactions reveals a novel method for the analysis of ligand-receptor interactions. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1544:350-7. [PMID: 11341944 DOI: 10.1016/s0167-4838(00)00249-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A novel method has been developed for the analysis of ligand-receptor interactions. The method utilizes binding data generated from the analysis of chimeric proteins with chimeric peptides. To each chimeric part of the peptide and receptor are assigned descriptors, thus creating a matrix of X descriptors. These descriptors are then correlated with the experimentally determined interaction binding affinities for each chimeric receptor/peptide pair by use of partial least-squares projection to latent structures (PLS). The method was applied to analyze the interactions of chimeric MSH-peptides with wild-type MC1 and MC3 receptors, and MC1/MC3 receptor chimeras (in total 40 peptide-receptor combinations). Two types of PLS models could be created, one that revealed the relationships between receptor and peptide structure and peptide binding pK(i) values (i.e., affinity) (R2 and Q2 being 0.71 and 0.62, respectively), and another that revealed the relationships between peptide and receptor structure and peptide-receptor selectivity (R2 and Q2 being 0.64 and 0.57, respectively). After addition of cross-terms these models improved significantly; the R2 and Q2 being 0.93 and 0.75 for affinity, and 0.92 and 0.72 for selectivity, respectively. The analysis shows that the high affinity of the MSH-peptides is primarily achieved by interactions of the peptides' C-terminal amino acids with TM2 and TM3 of the receptor, and, to a lesser extent, by the interaction of the N-terminus with TM1, TM2 and TM3 of the receptor. However, in contrast, the MC1 receptor selectivity is primarily determined by an interaction of the peptides' N-termini with TM2/3 of the receptor. Moreover, the cross-terms of the PLS model revealed the existence of a strong interaction between TM6/7 and TM2/3 of the receptors.
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Affiliation(s)
- P Prusis
- Department of Pharmaceutical Pharmacology, Upssala University, Sweden
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48
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Modelling G-protein coupled receptors. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1380-7323(01)80010-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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49
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Wikberg JE, Muceniece R, Mandrika I, Prusis P, Lindblom J, Post C, Skottner A. New aspects on the melanocortins and their receptors. Pharmacol Res 2000; 42:393-420. [PMID: 11023702 DOI: 10.1006/phrs.2000.0725] [Citation(s) in RCA: 257] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Knowledge of melanocortins and their receptors has increased tremendously over the last few years. The cloning of five melanocortin receptors, and the discovery of two endogenous antagonists for these receptors, agouti and agouti-related peptide, have sparked intense interest in the field. Here we give a comprehensive review of the pharmacology, physiology and molecular biology of the melanocortins and their receptors. In particular, we review the roles of the melanocortins in the immune system, behaviour, feeding, the cardiovascular system and melanoma. Moreover, evidence is discussed suggesting that while many of the actions of the melanocortins are mediated via melanocortin receptors, some appear to be mediated via mechanisms distinct from melanocortin receptors.
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Affiliation(s)
- J E Wikberg
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Box 591 BMC, SE751 24, Sweden.
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Schiöth HB, Phillips SR, Rudzish R, Birch-Machin MA, Wikberg JE, Rees JL. Loss of function mutations of the human melanocortin 1 receptor are common and are associated with red hair. Biochem Biophys Res Commun 1999; 260:488-91. [PMID: 10403794 DOI: 10.1006/bbrc.1999.0935] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The melanocortin 1 receptor is a G-protein-coupled receptor that acts as a control point for control of the eumelanin/phaeomelanin ratio in mouse hair. MC1 receptor loss of function mutations lead to an increase in the ratio of phaeomelanin/eumelanin in many mammals resulting in yellow or red coat colours. We have previously shown that several common point mutations in the human MC1 receptor are overrepresented in North European redheads and in individuals with pale skin. In order to determine the functional significance of these changes we have carried out transfection and binding studies. Expression of the Val60Leu, Arg142His, Arg151Cys, Arg160Trp, and Asp294His receptors in COS 1 cells revealed that these receptors were unable to stimulate cAMP production as strongly as the wild type receptor in response to alpha-melanocyte-stimulating hormone stimulation. None of the mutant receptors displayed complete loss of alphaMSH binding, with only the Arg142His and Asp294His displaying a slight reduction in binding affinity.
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Affiliation(s)
- H B Schiöth
- Department of Pharmaceutical Pharmacology, Uppsala University, Uppsala, Sweden
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