1
|
Normand C, Breton B, Salze M, Barbeau E, Mancini A, Audet M. A systematic analysis of prostaglandin E2 type 3 receptor isoform signaling reveals isoform- and species-dependent L798106 Gαz-biased agonist responses. Eur J Pharmacol 2022; 927:175043. [DOI: 10.1016/j.ejphar.2022.175043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 05/17/2022] [Accepted: 05/17/2022] [Indexed: 11/15/2022]
|
2
|
Yano A, Takahashi Y, Moriguchi H, Inazumi T, Koga T, Otaka A, Sugimoto Y. An aromatic amino acid within intracellular loop 2 of the prostaglandin EP2 receptor is a prerequisite for selective association and activation of Gαs. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:615-622. [PMID: 28336329 DOI: 10.1016/j.bbalip.2017.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 03/17/2017] [Accepted: 03/18/2017] [Indexed: 10/19/2022]
Abstract
We previously demonstrated that the aromatic moiety of Tyr143 within the intracellular loop 2 (ICL2) region of the prostaglandin EP2 receptor plays a crucial role in Gs coupling. Here we investigated whether the ICL2 of the EP2 receptor directly binds to Gαs and whether an aromatic moiety affects this interaction. In Chinese hamster ovary cells, mutations of Tyr143 reduced the ability of the EP2 receptor to interact with G proteins as demonstrated by GTPγS sensitivity, as well as the ability of agonist-induced cAMP formation, with the rank order of Phe>Tyr (wild-type)=Trp>Leu>Ala (=0). We found that the wild-type ICL2 peptide (i2Y) and its mutant with Phe at Tyr143 (i2F) inhibited receptor-G protein complex formation of wild-type EP2 in membranes, whereas the Ala-substituted mutant (i2A) did not. Specific interactions between these peptides and the Gαs protein were detected by surface plasmon resonance, but Gαs showed different association rates, with a rank order of i2F>i2Y≫i2A, with similar dissociation rates. Moreover, i2F and i2Y, but not i2A activated membrane adenylyl cyclase. These results indicate that the ICL2 region of the EP2 receptor is its potential interaction site with Gαs, and that the aromatic side chain moiety at position 143 is a determinant for the accessibility of the ICL2 to the Gαs protein.
Collapse
Affiliation(s)
- Akiko Yano
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yuko Takahashi
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hiromi Moriguchi
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Tomoaki Inazumi
- Department of Pharmaceutical Biochemistry, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; AMED-CREST, Tokyo 100-0004, Japan
| | - Tomoaki Koga
- Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto, Japan
| | - Akira Otaka
- Department of Bioorganic Synthetic Chemistry, Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima, Japan
| | - Yukihiko Sugimoto
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan; Department of Pharmaceutical Biochemistry, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; AMED-CREST, Tokyo 100-0004, Japan.
| |
Collapse
|
3
|
Xu H, Fu JL, Miao YF, Wang CJ, Han QF, Li S, Huang SZ, Du SN, Qiu YX, Yang JC, Gustafsson JÅ, Breyer RM, Zheng F, Wang NP, Zhang XY, Guan YF. Prostaglandin E2 receptor EP3 regulates both adipogenesis and lipolysis in mouse white adipose tissue. J Mol Cell Biol 2016; 8:518-529. [PMID: 27436752 PMCID: PMC5181317 DOI: 10.1093/jmcb/mjw035] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 03/29/2016] [Accepted: 04/04/2016] [Indexed: 12/20/2022] Open
Abstract
Among the four prostaglandin E2 receptors, EP3 receptor is the one most abundantly expressed in white adipose tissue (WAT). The mouse EP3 gene gives rise to three isoforms, namely EP3α, EP3β, and EP3γ, which differ only at their C-terminal tails. To date, functions of EP3 receptor and its isoforms in WAT remain incompletely characterized. In this study, we found that the expression of all EP3 isoforms were downregulated in WAT of both db/db and high-fat diet-induced obese mice. Genetic ablation of three EP3 receptor isoforms (EP3-/- mice) or EP3α and EP3γ isoforms with EP3β intact (EP3β mice) led to an obese phenotype with increased food intake, decreased motor activity, reduced insulin sensitivity, and elevated serum triglycerides. Since the differentiation of preadipocytes and mouse embryonic fibroblasts to adipocytes was markedly facilitated by either pharmacological blockade or genetic deletion/inhibition of EP3 receptor via the cAMP/PKA/PPARγ pathway, increased adipogenesis may contribute to obesity in EP3-/- and EP3β mice. Moreover, both EP3-/- and EP3β mice had increased lipolysis in WAT mainly due to the activated cAMP/PKA/hormone-sensitive lipase pathway. Taken together, our findings suggest that EP3 receptor and its α and γ isoforms are involved in both adipogenesis and lipolysis and influence food intake, serum lipid levels, and insulin sensitivity.
Collapse
Affiliation(s)
- Hu Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Jia-Lin Fu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yi-Fei Miao
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Chun-Jiong Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Qi-Fei Han
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Sha Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Shi-Zheng Huang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Sheng-Nan Du
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yu-Xiang Qiu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Ji-Chun Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Jan-Åke Gustafsson
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Richard M Breyer
- Department of Veterans Affairs, Tennessee Valley Health Authority, and Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Feng Zheng
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Nan-Ping Wang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Xiao-Yan Zhang
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian 116044, China.,Department of Physiology, AstraZeneca-Shenzhen University Joint Institute of Nephrology, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - You-Fei Guan
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China .,Advanced Institute for Medical Sciences, Dalian Medical University, Dalian 116044, China
| |
Collapse
|
4
|
Natarajan C, Hata AN, Hamm HE, Zent R, Breyer RM. Extracellular loop II modulates GTP sensitivity of the prostaglandin EP3 receptor. Mol Pharmacol 2012; 83:206-16. [PMID: 23087260 DOI: 10.1124/mol.112.080473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unlike the majority of G protein-coupled receptors, the prostaglandin E(2) (PGE(2)) E-prostanoid 3 (EP3) receptor binds agonist with high affinity that is insensitive to the presence of guanosine 5[prime]-O-(3-thio)triphosphate (GTPγS). We report the identification of mutations that confer GTPγS sensitivity to agonist binding. Seven point mutations were introduced into the conserved motif in the second extracellular loop (ECII) of EP3, resulting in acquisition of GTP-sensitive agonist binding. One receptor mutation W203A was studied in detail. Loss of agonist binding was observed on intact human embryonic kidney 293 cells expressing the W203A receptor, conditions where high GTP levels are present; however, high affinity binding [(3)H]PGE(2) was observed in broken cell preparations washed free of GTP. The [(3)H]PGE(2) binding of W203A in broken cell membrane fractions was inhibited by addition of GTPγS (IC(50) 21 ± 1.8 nM). Taken together, these results suggest that the wild-type EP3 receptor displays unusual characteristics of the complex coupled equilibria between agonist-receptor and receptor-G protein interaction. Moreover, mutation of ECII can alter this coupled equilibrium from GTP-insensitive agonist binding to more conventional GTP-sensitive binding. This suggests that for the mutant receptors, ECII plays a critical role in linking the agonist bound receptor conformation to the G protein nucleotide bound state.
Collapse
Affiliation(s)
- Chandramohan Natarajan
- Division of Nephrology, Vanderbilt University School of Medicine, S3223 MCN, 1161 21st Avenue, Nashville, TN 37232-2372, USA
| | | | | | | | | |
Collapse
|
5
|
Woodward DF, Jones RL, Narumiya S. International Union of Basic and Clinical Pharmacology. LXXXIII: classification of prostanoid receptors, updating 15 years of progress. Pharmacol Rev 2011; 63:471-538. [PMID: 21752876 DOI: 10.1124/pr.110.003517] [Citation(s) in RCA: 321] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
It is now more than 15 years since the molecular structures of the major prostanoid receptors were elucidated. Since then, substantial progress has been achieved with respect to distribution and function, signal transduction mechanisms, and the design of agonists and antagonists (http://www.iuphar-db.org/DATABASE/FamilyIntroductionForward?familyId=58). This review systematically details these advances. More recent developments in prostanoid receptor research are included. The DP(2) receptor, also termed CRTH2, has little structural resemblance to DP(1) and other receptors described in the original prostanoid receptor classification. DP(2) receptors are more closely related to chemoattractant receptors. Prostanoid receptors have also been found to heterodimerize with other prostanoid receptor subtypes and nonprostanoids. This may extend signal transduction pathways and create new ligand recognition sites: prostacyclin/thromboxane A(2) heterodimeric receptors for 8-epi-prostaglandin E(2), wild-type/alternative (alt4) heterodimers for the prostaglandin FP receptor for bimatoprost and the prostamides. It is anticipated that the 15 years of research progress described herein will lead to novel therapeutic entities.
Collapse
Affiliation(s)
- D F Woodward
- Dept. of Biological Sciences RD3-2B, Allergan, Inc., 2525 Dupont Dr., Irvine, CA 92612, USA.
| | | | | |
Collapse
|
6
|
Fujino H, Murayama T, Regan JW. Assessment of constitutive activity in E-type prostanoid receptors. Methods Enzymol 2011; 484:95-107. [PMID: 21036228 DOI: 10.1016/b978-0-12-381298-8.00005-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The potential for G-protein-coupled receptors (GPCRs) to show constitutive activity is emerging as one of the fundamental properties of GPCRs signal transduction. Indeed, of the four subtypes of E-type prostanoid (EP) receptors, the EP3 and EP4 subtypes show constitutive activity in addition to their innate ligand-dependent activation of signaling pathways. The constitutive activity of the EP3 and EP4 receptor subtypes was discovered during the initial characterizations of these receptors and may be important for setting the basal level of cellular tone in the given signaling pathway. This chapter introduces some of the methods that can be used to study the constitutive activity of the EP receptors.
Collapse
Affiliation(s)
- Hiromichi Fujino
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | | | | |
Collapse
|
7
|
Pathe-Neuschäfer-Rube A, Neuschäfer-Rube F, Püschel G. Role of the ERC motif in the proximal part of the second intracellular loop and the C-terminal domain of the human prostaglandin F2alpha receptor (hFP-R) in G-protein coupling control. Biochem J 2009; 388:317-24. [PMID: 15651980 PMCID: PMC1186721 DOI: 10.1042/bj20041321] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The human FP-R (F2alpha prostaglandin receptor) is a Gq-coupled heptahelical ectoreceptor, which is of significant medical interest, since it is a potential target for the treatment of glaucoma and preterm labour. On agonist exposure, it mediates an increase in intracellular inositol phosphate formation. Little is known about the structures that govern the agonist-dependent receptor activation. In other prostanoid receptors, the C-terminal domain has been inferred in the control of agonist-dependent receptor activation. A DRY motif at the beginning of the second intracellular loop is highly conserved throughout the G-protein-coupled receptor family and appears to be crucial for controlling agonist-dependent receptor activation. It is replaced by an ERC motif in the FP-R and no evidence for the relevance of this motif in ligand-dependent activation of prostanoid receptors has been provided so far. The aim of the present study was to elucidate the potential role of the C-terminal domain and the ERC motif in agonist-controlled intracellular signalling in FP-R mutants generated by site-directed mutagenesis. It was found that substitution of the acidic Glu(132) in the ERC motif by a threonine residue led to full constitutive activation, whereas truncation of the receptor's C-terminal domain led to partial constitutive activation of all three intracellular signal pathways that had previously been shown to be activated by the FP-R, i.e. inositol trisphosphate formation, focal adhesion kinase activation and T-cell factor signalling. Inositol trisphosphate formation and focal adhesion kinase phosphorylation were further enhanced by ligand binding in cells expressing the truncation mutant but not the E132T (Glu132-->Thr) mutant. Thus C-terminal truncation appeared to result in a receptor with partial constitutive activation, whereas substitution of Glu132 by threonine apparently resulted in a receptor with full constitutive activity.
Collapse
Affiliation(s)
- Andrea Pathe-Neuschäfer-Rube
- Institut für Ernährungswissenschaft, Abteilung Biochemie der Ernährung, Universität Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Frank Neuschäfer-Rube
- Institut für Ernährungswissenschaft, Abteilung Biochemie der Ernährung, Universität Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Gerhard P. Püschel
- Institut für Ernährungswissenschaft, Abteilung Biochemie der Ernährung, Universität Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
- To whom correspondence should be addressed (email )
| |
Collapse
|
8
|
NMR structure of an intracellular third loop peptide of human GABAB receptor. Biochem Biophys Res Commun 2008; 366:681-4. [DOI: 10.1016/j.bbrc.2007.11.164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Accepted: 11/29/2007] [Indexed: 01/05/2023]
|
9
|
Kikkou T, Matsumoto O, Ohkubo T, Kobayashi Y, Tsujimoto G. NMR structure of a human homologous methuselah gene receptor peptide. Biochem Biophys Res Commun 2006; 352:17-20. [PMID: 17109822 DOI: 10.1016/j.bbrc.2006.10.140] [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] [Received: 10/19/2006] [Accepted: 10/23/2006] [Indexed: 10/23/2022]
Abstract
Human APG1 gene is homologous to Drosophila methuselah gene associated with extended life span. A peptide (APG1: RNGKRSNRTLREE) corresponding to a predicted region of the intracellular third loop of G protein-coupled receptor coded in human APG1 gene could activate Gi protein alpha subunit directly. The three-dimensional molecular structure of the peptide in SDS-d25 micelles was determined by 2D 1H NMR spectroscopy. APG1 formed an alpha-helical structure at the C-terminal site and a positive charge cluster at the N-terminal site. The cluster was also found in several other Gi protein-coupled receptor peptides. Therefore, the positive charge cluster on the helical structure might be engaged in G protein activation.
Collapse
Affiliation(s)
- Tatsuhiko Kikkou
- Faculty of Pharmaceutical Sciences, Chiba Institute of Science, Choshi, Chiba 288-0025, Japan
| | | | | | | | | |
Collapse
|
10
|
Hatae N. [Cooperation of two subtypes of PGE2 receptor, Gi coupled EP3 and Gs coupled EP2 or EP4 subtype]. YAKUGAKU ZASSHI 2004; 123:837-43. [PMID: 14577329 DOI: 10.1248/yakushi.123.837] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Four prostaglandin E (EP) receptor subtypes have been identified and cloned, designated as EP1, EP2, EP3 and EP4. These EP receptors are members of the G-protein coupled receptor family. EP3 receptor signals are primarily involved in inhibition of adenylyl cyclase via Gi activation, while EP2 and EP4 receptor signals cause a stimulation of adenylyl cyclase via Gs activation. Immune cells, such as mast cells, express multiple EP subtypes on their cell membranes, but few studies have been conducted to understand exactly what signals the main flow for the multiple subtypes expressing immune cells. We previously demonstrated that activation of Gi-coupled EP3 receptor exhibited a cooperative effect on cAMP synthesis induced by Gs-coupled EP2 receptor in COS-7 cells. Here we report that a selective EP4 agonist-induced adenylyl cyclase activity was augmented by simultaneous addition of a selective EP3 agonist in mastocytoma P-815 cells, which express mRNAs for both EP3 and EP4 subtypes. The augmentation in cAMP synthesis was found to be pertussis toxin-sensitive. P-815 cells are demonstrated to bind to Pronectin-F, a proteolytic fragment of fibronectin, in adhesion protein of the extracellular matrix, by addition of PGE2, which is mediated by PKA. The binding of P-815 cells to Pronectin-F mediated by EP4 receptor was augmented by the EP3 receptor. These findings indicate that two subtypes of PGE2 receptors, EP3 and EP4, cooperatively activate the cAMP-mediated adhesion event through induction of fibronectin ligand elicited by PGE2 in P-815 cells. Furthermore, the PGE2-induced adhesion response may contribute to the mast cell recruitment function on extracellular matrix during inflammation.
Collapse
MESH Headings
- Adenylyl Cyclases
- Animals
- Cell Adhesion
- Cyclic AMP/biosynthesis
- Cyclic AMP/physiology
- Extracellular Matrix/metabolism
- Fibronectins/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Humans
- Mast Cells
- Protein Binding
- Receptors, Prostaglandin E/agonists
- Receptors, Prostaglandin E/physiology
- Receptors, Prostaglandin E, EP1 Subtype
- Receptors, Prostaglandin E, EP2 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Receptors, Prostaglandin E, EP4 Subtype
- Signal Transduction/physiology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- Noriyuki Hatae
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
| |
Collapse
|
11
|
Sugimoto Y, Nakato T, Kita A, Hatae N, Tabata H, Tanaka S, Ichikawa A. Functional domains essential for Gs activity in prostaglandin EP2 and EP3 receptors. Life Sci 2004; 74:135-41. [PMID: 14607240 DOI: 10.1016/j.lfs.2003.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The interaction of cell surface hormone receptors with heterotrimeric G proteins is crucial for hormonal actions. The domains of the receptor, which interact with and activate G protein, have been extensively studied. However, precise molecular mechanisms underlying regulation of the receptor-induced G protein activation are still poorly understood. Prostaglandin E(2) (PGE(2)) receptors comprise of four subtypes, EP1, EP2, EP3 and EP4. Among them, EP2 and EP4 couple to Gs and EP3 to Gi. To assess the functional domains essential for Gs activation in prostanoid receptors, EP2, EP3beta and each intracellular loop- (IC-) interchanged EP2/EP3 chimeras were tested for agonist binding and functional responses. In EP2 receptor, substitution of IC1 or IC3 resulted in loss of binding activity, while substitution of IC2, N- (IC2N) or C-terminal half region of IC2 (IC2C) had no effects on the binding activity. Wild-type EP2 and IC2C-substituted EP2 showed agonist-induced Gs activity, but IC2- and IC2N-substituted EP2 failed to elicit Gs activity upon agonist stimulation. On the other hand, in EP3 receptor substitution of IC1 resulted in loss of PGE(2) binding, while substitution of IC2, IC3, IC2N or IC2C had no effects on binding activity. Wild-type EP3beta, IC3- or IC2C-substituted EP3 failed to show Gs activity upon agonist stimulation, but IC2- or IC2N-substituted EP3 chimera showed agonist-dependent Gs activity. These results indicated that the second intracellular loop of the EP2 plays an essential role in activation of Gs.
Collapse
MESH Headings
- Animals
- Cell Line
- Cyclic AMP/biosynthesis
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- GTP-Binding Protein alpha Subunits, Gs/genetics
- GTP-Binding Protein alpha Subunits, Gs/physiology
- Kinetics
- Mice
- Mutation/genetics
- Nucleic Acid Hybridization
- Receptors, Prostaglandin E/genetics
- Receptors, Prostaglandin E/physiology
- Receptors, Prostaglandin E, EP2 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Recombinant Fusion Proteins
- Signal Transduction/physiology
Collapse
Affiliation(s)
- Yukihiko Sugimoto
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Sakyo, Japan
| | | | | | | | | | | | | |
Collapse
|
12
|
Sugimoto Y, Nakato T, Kita A, Takahashi Y, Hatae N, Tabata H, Tanaka S, Ichikawa A. A cluster of aromatic amino acids in the i2 loop plays a key role for Gs coupling in prostaglandin EP2 and EP3 receptors. J Biol Chem 2003; 279:11016-26. [PMID: 14699136 DOI: 10.1074/jbc.m307404200] [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] [Indexed: 12/31/2022] Open
Abstract
To assess the structural requirements for G(s) coupling by prostaglandin E receptors (EPs), the G(s)-coupled EP2 and G(i)-coupled EP3beta receptors were used to generate hybrid receptors. Interchanging of the whole i2 loop and its N-terminal half (i2N) had no effect on the binding of both receptors expressed in HEK293 cells. Agonist-induced cAMP formation was observed in wild type EP2 but not in the i2 loop- or i2N-substituted EP2. Wild type EP3beta left cAMP levels unaffected, whereas i2 loop- and i2N-substituted EP3 gained agonist-induced adenylyl cyclase stimulation. In EP2, the ability to stimulate cAMP formation was lost by mutation of Tyr(143) into Ala but retained by mutations into Phe, Trp, and Leu. Consistent with this observation, substitution of the equivalent His(140) enabled EP3beta to stimulate cAMP formation with the rank order of Phe > Tyr > Trp > Leu. The point mutation of His(140) into Phe was effective in another EP3 variant in which its C-terminal tail is different or lacking. Simultaneous mutation of the adjacent Trp(141) to Ala but not at the following Tyr(142) weakened the acquired ability to stimulate cAMP levels in the EP3 mutant. Mutation of EP2 at adjacent Phe(144) to Ala but not at Tyr(145) reduced the efficiency of agonist-induced cAMP formation. In Chinese hamster ovary cells stably expressing G(s)-acquired EP3 mutant, an agonist-dependent cAMP formation was observed, and pertussis toxin markedly augmented cAMP formation. These results suggest that a cluster of hydrophobic aromatic amino acids in the i2 loop plays a key role for G(s) coupling.
Collapse
MESH Headings
- Amino Acid Sequence
- Amino Acids, Aromatic/chemistry
- Amino Acids, Aromatic/metabolism
- Animals
- CHO Cells
- Cell Line
- Cricetinae
- GTP-Binding Protein alpha Subunits, Gs/chemistry
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Humans
- Molecular Sequence Data
- Receptors, Prostaglandin E/agonists
- Receptors, Prostaglandin E/chemistry
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP2 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Sequence Homology, Amino Acid
Collapse
Affiliation(s)
- Yukihiko Sugimoto
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Meyer-Kirchrath J, Hasse A, Schrör K. Preservation of Gi coupling of a chimeric EP3/I-type prostaglandin (IP) receptor. Biochem Pharmacol 1999; 58:471-6. [PMID: 10424767 DOI: 10.1016/s0006-2952(99)00119-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
For the EP3 subtype of prostaglandin E receptors, different C-terminal splice variants are known, which are coupled to distinct heterotrimeric GTP-binding proteins (G-proteins). To test the hypothesis that the C-terminal domain is essential for the G-protein-coupling specificity of the EP3 receptor, we exchanged the carboxyl-terminal tail of a porcine Gi-coupled EP3 receptor isoform for the corresponding C-terminal part of a Gs-coupled prostaglandin receptor. The porcine EP3 receptor was truncated at a lysine (K350) residue at the end of the seventh transmembrane region, representing the splicing site of the different EP3 receptor isoforms. The wild-type C-terminus (37 amino acids) was substituted by the C-terminal tail (89 amino acids) of the human I-type prostaglandin receptor (hIP-R). The G-protein coupling of the resulting chimeric receptor protein was studied in transfected Chinese hamster ovary (CHO) cells. Stimulation of the chimeric receptor protein with the EP3 receptor-specific agonist M&B 28.767 did not increase adenosine 3',5'-cyclic monophosphate (cAMP) formation but did reduce the forskolin-stimulated cAMP formation, indicating Gi coupling. Furthermore, the chimeric receptor did not show constitutive activity as demonstrated for the C-terminally truncated EP3 receptor. Thus, coupling specificity of the EP3 receptor is not exclusively mediated by the carboxyl-terminal tail, and constitutive activity of a C-terminally truncated EP3 receptor can be suppressed by the hIP-R C-terminus.
Collapse
Affiliation(s)
- J Meyer-Kirchrath
- Institut für Pharmakologie und Klinische Pharmakologie, Heinrich-Heine-Universität Düsseldorf, Germany
| | | | | |
Collapse
|