| 1. |
- Bjarnadóttir, Thóra K., et al.
(författare)
-
The human and mouse repertoire of the adhesion family of G-protein-coupled receptors
- 2004
-
Ingår i: Genomics. - : Elsevier BV. - 0888-7543 .- 1089-8646. ; 84:1, s. 23-33
-
Tidskriftsartikel (refereegranskat)abstract
- The adhesion G-protein-coupled receptors (GPCRs) (also termed LN-7TM or EGF-7TM receptors) are membrane-bound proteins with long N-termini containing multiple domains. Here, 2 new human adhesion-GPCRs, termed GPR133 and GPR144, have been found by searches done in the human genome databases. Both GPR133 and GPR144 have a GPS domain in their N-termini, while GPR144 also has a pentraxin domain. The phylogenetic analyses of the 2 new human receptors show that they group together without close relationship to the other adhesion-GPCRs. In addition to the human genes, mouse orthologues to those 2 and 15 other mouse orthologues to human were identified (GPR110, GPR111, GPR112, GPR113, GPR114, GPR115, GPR116, GPR123, GPR124, GPR125, GPR126, GPR128, LEC1, LEC2, and LEC3). Currently the total number of human adhesion-GPCRs is 33. The mouse and human sequences show a clear one-to-one relationship, with the exception of EMR2 and EMR3, which do not seem to have orthologues in mouse. EST expression charts for the entire repertoire of adhesion-GPCRs in human and mouse were established. Over 1600 ESTs were found for these receptors, showing widespread distribution in both central and peripheral tissues. The expression patterns are highly variable between different receptors, indicating that they participate in a number of physiological processes.
|
|
| 2. |
|
|
| 3. |
- Fredriksson, Robert, et al.
(författare)
-
Novel human G protein-coupled receptors with long N-terminals containing GPS domains and Ser/Thr-rich regions
- 2002
-
Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 531:3, s. 407-414
-
Tidskriftsartikel (refereegranskat)abstract
- We report eight novel members of the superfamily of human G protein-coupled receptors (GPCRs) found by searches in the human genome databases, termed GPR97, GPR110, GPR111, GPR112, GPR113, GPR114, GPR115 and GPR116. Phylogenetic analysis shows that these are additional members of a family of GPCRs with long N-termini, previously termed EGF-7TM, LNB-7TM, B2 or LN-7TM. Five of the receptors form their own phylogenetic cluster, while three others form a cluster with the previously reported HE6 and GPR56 (TM7XN1). All the receptors have a GPS domain in their N-terminus and long Ser/Thr-rich regions forming mucin-like stalks. GPR113 has a hormone binding domain and one EGF domain. GPR112 has over 20 Ser/Thr repeats and a pentraxin domain. GPR116 has two immunoglobulin-like repeats and a SEA box. We found several human EST sequences for most of the receptors showing differential expression patterns, which may indicate that some of these receptors participate in reproductive functions while others are more likely to have a role in the immune system.
|
|
| 4. |
- Fredriksson, Robert, et al.
(författare)
-
The G-Protein-Coupled Receptors in the Human Genome Form Five Main Families : Phylogenetic Analysis, Paralogon Groups, and Fingerprints
- 2003
-
Ingår i: Molecular Pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0026-895X .- 1521-0111. ; 63:6, s. 1256-1272
-
Tidskriftsartikel (refereegranskat)abstract
- The superfamily of G-protein-coupled receptors (GPCRs) is very diverse in structure and function and its members are among the most pursued targets for drug development. We identified more than 800 human GPCR sequences and simultaneously analyzed 342 unique functional nonolfactory human GPCR sequences with phylogenetic analyses. Our results show, with high bootstrap support, five main families, named glutamate, rhodopsin, adhesion, frizzled/taste2, and secretin, forming the GRAFS classification system. The rhodopsin family is the largest and forms four main groups with 13 sub-branches. Positions of the GPCRs in chromosomal paralogons regions indicate the importance of tetraploidizations or local gene duplication events for their creation. We also searched for "fingerprint" motifs using Hidden Markov Models delineating the putative inter-relationship of the GRAFS families. We show several common structural features indicating that the human GPCRs in the GRAFS families share a common ancestor. This study represents the first overall map of the GPCRs in a single mammalian genome. Our novel approach of analyzing such large and diverse sequence sets may be useful for studies on GPCRs in other genomes and divergent protein families.
|
|
| 5. |
- Haitina, Tatjana, et al.
(författare)
-
Cloning, tissue distribution, pharmacology and three-dimensional modelling of melanocortin receptors 4 and 5 in rainbow trout suggest close evolutionary relationship of these subtypes
- 2004
-
Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 380:2, s. 475-486
-
Tidskriftsartikel (refereegranskat)abstract
- The rainbow trout (Oncorhynchus mykiss) is one of the most widely used fish species in aquaculture and physiological research. In the present paper, we report the first cloning, 3D (three-dimensional) modelling, pharmacological characterization and tissue distribution of two melanocortin (MC) receptors in rainbow trout. Phylogenetic analysis indicates that these receptors are orthologues of the human MC4 and MC5 receptors. We created 3D molecular models of these rainbow trout receptors and their human counterparts. These models suggest greater divergence between the two human receptors than between their rainbow trout counterparts. The pharmacological analyses demonstrated that ACTH (adrenocorticotropic hormone) had surprisingly high affinity for the rainbow trout MC4 and MC5 receptors, whereas alpha-, beta- and gamma-MSH (melanocyte-stimulating hormone) had lower affinity. In second-messenger studies, the cyclic MSH analogues MTII and SHU9119 acted as potent agonist and antagonist respectively at the rainbow trout MC4 receptor, indicating that these ligands are suitable for physiological studies in rainbow trout. Interestingly, we found that the rainbow trout MC4 receptor has a natural high-affinity binding site for zinc ions (0.5 microM) indicating that zinc may play an evolutionary conserved role at this receptor. Reverse transcription PCR indicates that the rainbow trout receptors are expressed both in peripheral tissues and in the central nervous system, including the telencephalon, optic tectum and hypothalamus. Overall, this analysis indicates that the rainbow trout MC4 and MC5 receptors have more in common than their mammalian counterparts, which may suggest that these two receptors have a closer evolutionary relationship than the other MC receptor subtypes.
|
|
| 6. |
- Klovins, Janis, et al.
(författare)
-
Cloning of two melanocortin (MC) receptors in spiny dogfish : MC3 receptor in cartilaginous fish shows high affinity to ACTH-derived peptides while it has lower preference to gamma-MSH
- 2004
-
Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 271:21, s. 4320-4331
-
Tidskriftsartikel (refereegranskat)abstract
- We report the cloning and characterization of two melanocortin receptors (MCRs) from the spiny dogfish (Squalus acanthias) (Sac). Phylogenetic analysis shows that these shark receptors are orthologues of the MC3R and MC5R subtypes, sharing 65% and 70% overall amino acid identity with the human counterparts, respectively. The SacMC3R was expressed and pharmacologically characterized in HEK293 cells. The radioligand binding results show that this receptor has high affinity for adrenocorticotropic hormone (ACTH)-derived peptides while it has comparable affinity for alpha- and beta-melanocyte stimulating hormone (MSH), and slightly lower affinity for gamma-MSH when compared with the human orthologue. ACTH(1-24) has high potency in a second-messenger cAMP assay while alpha- and gamma-MSH had slightly lower potency in cells expressing the SacMC3R. We used receptor-enhanced green fluorescence protein (EGFP) fusion to show the presence of SacMC3R in plasma membrane of Chinese hamster ovary and HEK293 cells but the SacMC5R was retained in intracellular compartments of these cells hindering pharmacological characterization. The anatomical distribution of the receptors were determined using reverse transcription PCR. The results showed that the SacMC3R is expressed in the hypothalamus, brain stem and telencephalon, optic tectum and olfactory bulbs, but not in the cerebellum of the spiny dogfish while the SacMC5R was found only in the same central regions. This report describes the first molecular characterization of a MC3R in fish. The study indicates that many of the important elements of the MC system existed before radiation of gnathostomes, early in vertebrate evolution, at least 450 million years ago.
|
|
| 7. |
- Lagerström, Malin C., et al.
(författare)
-
High affinity agonistic metal ion binding sites within the melanocortin 4 receptor illustrate conformational change of transmembrane region 3
- 2003
-
Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 278:51, s. 51521-51526
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 8. |
- Ling, Maria K, et al.
(författare)
-
The melanocortin receptor subtypes in chicken have high preference to ACTH-derived peptides
- 2004
-
Ingår i: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 143:5, s. 626-637
-
Tidskriftsartikel (refereegranskat)abstract
- 1 Melanocortin (MC) receptors are widely distributed throughout the body of chicken, like in mammals, and participate in a wide range of physiological functions. 2 To clarify the pharmacological impact of ligands acting in the MC system, we expressed the chicken MC1, MC2, MC3, MC4 and MC5 (cMC1-5) receptors in eukaryotic cells and performed comprehensive pharmacological characterization of the potency of endogenous and synthetic melanocortin peptides. 3 Remarkably, the cMC receptors displayed high affinity for ACTH-derived peptides and in general low affinity for alpha-MSH. It is evident that not only the cMC2 receptor but also the other cMC receptors interact with ACTH-derived peptide through an epitope beyond the sequence of alpha-MSH. 4 The synthetic ligand MTII was found to be a potent agonist whereas HS024 was a potent antagonist at the cMC4 receptor, indicating that these ligands are suitable for physiological studies in chicken. 5 We also show the presence of prohormone convertase 1 (PC1) and PC2 genes in chicken, and that these peptides are coexpressed with proopiomelanocortin (POMC) in various tissues.
|
|
| 9. |
- Ploj, Karolina, et al.
(författare)
-
Effects of melanocortin receptor ligands on ethanol intake and opioid peptide levels in alcohol-preferring AA rats
- 2002
-
Ingår i: Brain Research Bulletin. - 0361-9230 .- 1873-2747. ; 59:2, s. 97-104
-
Tidskriftsartikel (refereegranskat)abstract
- Melanocortin (MC) peptides are suggested to play a role in opiate dependence, where they antagonise the addictive properties of opiates. To further study the involvement of the MCs in drug dependence, we analysed the effects of the MC(4)-receptor antagonist HS014 (1 nmol/rat), and the non-selective MC-receptor agonist MTII (1 nmol/rat), using i.c.v. administration, on ethanol intake in alcohol-preferring AA rats. The rats had access to ethanol during 40 days, resulting in a mean ethanol intake of 6.6 g/kg/day, before treatment. One group received only artificial cerebrospinal fluid solution. MTII caused a reduction in ethanol intake and ethanol preference, whereas HS014 was without effect. No effect on water intake was observed. A decrease in food intake was detected after MTII, whereas HS014 induced an increase in food intake. Analysis of dynorphin B and Met-enkephalin-Arg(6)Phe(7) immunoreactive levels revealed that MTII and HS014 altered opioid peptide levels in several brain areas and the pituitary gland of the rats with an established ethanol intake. This is the first report showing that manipulation of the MC-receptor system changes ethanol intake in chronically ethanol-drinking AA rats. In addition, manipulation of the MC system modulates ethanol-induced changes in opioid peptide levels.
|
|
| 10. |
- Ringholm, Aneta I., 1971-
(författare)
-
Cloning, Expression, Pharmacological Characterization and Anatomical Distribution of Melanocortin Receptors in an Evolutionary Perspective
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The melanocortin (MC) receptors are G-protein coupled receptors thatparticipate in several important physiological functions such as the regulation of the energy balance. This thesis focuses on the evolutionary aspect of the MC receptors and their pharmacology.One MC4 receptor and two MC5 receptor subtypes were found in a teleost fish, zebrafish. This indicates 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. Moreover, we found a MC4 receptor from a shark, spiny dogfish that represents the most distant MC receptor gene cloned to date. We also characterized the pharmacology of a MC4 receptor in goldfish. The conserved central expression pattern and physiological role in regulation of food intake of the MC4 receptor suggests that neuronal pathways of the melanocortin system may be important for regulation of energy homeostasis in most vertebrates. We determined the chromosomal position of the chicken MC receptors genes and found conserved synteny of the MC2, MC5, and MC4 receptor genes. These results suggest that there exist a clustering of these genes that is ancient. Analysis of conserved synteny with mammalian genomes and paralogon segments prompted us to predict an ancestral gene organization that may explain how this family has been formed through both local duplication and tetraploidization processes.There are several common point mutations in the human MC1 receptor that are over represented in North European red-heads, and in individuals with pale skin. We pharmacologically characterised four naturally occurring human MC1 receptor variants providing molecular explanation to the respective phenotype.The MC receptor subtypes have highly diverse physiological functions despite having relative high similarities in their primary structure. Our studies on the structural and functional properties of the MC receptor subtypes have provided insight into the molecular mechanism of how the specification of these receptors may have occurred.
|
|
