1
|
Radomsky T, Anderson RC, Millar RP, Newton CL. Restoring function to inactivating G protein-coupled receptor variants in the hypothalamic-pituitary-gonadal axis 1. J Neuroendocrinol 2024:e13418. [PMID: 38852954 DOI: 10.1111/jne.13418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 03/30/2024] [Accepted: 05/15/2024] [Indexed: 06/11/2024]
Abstract
G protein-coupled receptors (GPCRs) are central to the functioning of the hypothalamic-pituitary-gonadal axis (HPG axis) and include the rhodopsin-like GPCR family members, neurokinin 3 receptor, kappa-opioid receptor, kisspeptin 1 receptor, gonadotropin-releasing hormone receptor, and the gonadotropin receptors, luteinizing hormone/choriogonadotropin receptor and follicle-stimulating hormone receptor. Unsurprisingly, inactivating variants of these receptors have been implicated in a spectrum of reproductive phenotypes, including failure to undergo puberty, and infertility. Clinical induction of puberty in patients harbouring such variants is possible, but restoration of fertility is not always a realisable outcome, particularly for those patients suffering from primary hypogonadism. Thus, novel pharmaceuticals and/or a fundamental change in approach to treating these patients are required. The increasing wealth of data describing the effects of coding-region genetic variants on GPCR function has highlighted that the majority appear to be dysfunctional as a result of misfolding of the encoded receptor protein, which, in turn, results in impaired receptor trafficking through the secretory pathway to the cell surface. As such, these intracellularly retained receptors may be amenable to 'rescue' using a pharmacological chaperone (PC)-based approach. PCs are small, cell permeant molecules hypothesised to interact with misfolded intracellularly retained proteins, stabilising their folding and promoting their trafficking through the secretory pathway. In support of the use of this approach as a viable therapeutic option, it has been observed that many rescued variant GPCRs retain at least a degree of functionality when 'rescued' to the cell surface. In this review, we examine the GPCR PC research landscape, focussing on the rescue of inactivating variant GPCRs with important roles in the HPG axis, and describe what is known regarding the mechanisms by which PCs restore trafficking and function. We also discuss some of the merits and obstacles associated with taking this approach forward into a clinical setting.
Collapse
Affiliation(s)
- Tarryn Radomsky
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Ross C Anderson
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Robert P Millar
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Faculty of Health Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- School of Medicine, University of St Andrews, St Andrews, UK
| | - Claire L Newton
- Centre for Neuroendocrinology, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
2
|
Camacho E, Marie N, Dupas Q, Martel C, Nowoczyn M, Elie N, Rochais C, Töth G, Allouche S. Impact of T161, Y318 and S363 alanine mutations on regulation of the human delta-opioid receptor (hDOPr) induced by peptidic and alkaloid agonists. Neuropharmacology 2020; 179:108286. [PMID: 32841607 DOI: 10.1016/j.neuropharm.2020.108286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 08/07/2020] [Accepted: 08/18/2020] [Indexed: 11/16/2022]
Abstract
Previously, we showed a differential regulation of the human delta-opioid receptor (hDOPr) by etorphine and [D-Pen2, D-Pen5] enkephalin (DPDPE). To understand the molecular basis of such differences, we introduced 3 alanine mutations at the residues T161. Y318 and S363. Both wild type (WT) and hDOPr mutants were expressed in HEK cells containing endogenous arrestins or CFP-tagged arrestin 3, then desensitization, internalization, recycling and phosphorylation were studied. In a context of endogenous arrestin expression, a major difference in DOPr desensitization was observed between agonists that was modified with the T161A mutation upon etorphine and with the S363A substitution upon DPDPE exposure. While both agonists induced a major receptor internalization, T161A and S363A impaired DOPr sequestration only for etorphine. However, similar level of S363 phosphorylation was measured between agonists. When CFP-tagged arrestin 3 was over-expressed, a similar profile of desensitization was measured for both agonists. In this context, all the 3 alanine mutations decreased etorphine-induced receptor desensitization. Using FRET, we showed similar interactions between WT hDOPr and arrestin 3 under DPDPE and etorphine stimulation which were delayed by both the Y318A and the S363A substitutions for etorphine. Finally, hDOPr recycling was qualitatively evaluated by microscopy and showed neither arrestin 3/hDOPr colocalization nor major impact of alanine mutations except for the S363A which impaired internalization and recycling for etorphine. The T161, Y318 and S363 residues of hDOPr could underlie the differential regulation promoted by DPDPE and etorphine.
Collapse
Affiliation(s)
- Elise Camacho
- Laboratoire de Signalisation, électrophysiologie et Imagerie des Lésions D'ischémie-reperfusion Myocardique, Normandie Univ, UNICAEN, Caen, France
| | - Nicolas Marie
- Centre National de Recherche Scientifique, Unité Mixte de Recherche 8206, Institut National de La Santé et de La Recherche Médicale. U705, Université Paris Descartes, Laboratoire de Neuropsychopharmacologie des Addictions, 4 Avenue de L'observatoire, 75006, Paris, France
| | - Quentin Dupas
- Laboratoire de Signalisation, électrophysiologie et Imagerie des Lésions D'ischémie-reperfusion Myocardique, Normandie Univ, UNICAEN, Caen, France
| | - Caroline Martel
- Laboratoire de Signalisation, électrophysiologie et Imagerie des Lésions D'ischémie-reperfusion Myocardique, Normandie Univ, UNICAEN, Caen, France
| | - Marie Nowoczyn
- Laboratoire de Signalisation, électrophysiologie et Imagerie des Lésions D'ischémie-reperfusion Myocardique, Normandie Univ, UNICAEN, Caen, France
| | - Nicolas Elie
- Plateau D'Histo-Imagerie Quantitative, CmaBio(3), SF 4206 ICORE, Normandie Univ, Caen, France
| | - Christophe Rochais
- Centre D'Etudes et de Recherche sur le Médicament de Normandie (CERMN), Normandie Univ, UNICAEN, 14000, Caen, France
| | - Geza Töth
- Biological Research Centre, Institute of Biochemistry, Hungarian Academy of Sciences, Szeged, Hungary
| | - Stéphane Allouche
- Laboratoire de Signalisation, électrophysiologie et Imagerie des Lésions D'ischémie-reperfusion Myocardique, Normandie Univ, UNICAEN, Caen, France.
| |
Collapse
|
3
|
Núñez Miguel R, Sanders J, Furmaniak J, Smith BR. Structure and activation of the TSH receptor transmembrane domain. AUTOIMMUNITY HIGHLIGHTS 2016; 8:2. [PMID: 27921237 PMCID: PMC5136658 DOI: 10.1007/s13317-016-0090-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 11/23/2016] [Indexed: 12/30/2022]
Abstract
PURPOSE The thyroid-stimulating hormone receptor (TSHR) is the target autoantigen for TSHR-stimulating autoantibodies in Graves' disease. The TSHR is composed of: a leucine-rich repeat domain (LRD), a hinge region or cleavage domain (CD) and a transmembrane domain (TMD). The binding arrangements between the TSHR LRD and the thyroid-stimulating autoantibody M22 or TSH have become available from the crystal structure of the TSHR LRD-M22 complex and a comparative model of the TSHR LRD in complex with TSH, respectively. However, the mechanism by which the TMD of the TSHR and the other glycoprotein hormone receptors (GPHRs) becomes activated is unknown. METHODS We have generated comparative models of the structures of the inactive (TMD_In) and active (TMD_Ac) conformations of the TSHR, follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) TMDs. The structures of TMD_Ac and TMD_In were obtained using class A GPCR crystal structures for which fully active and inactive conformations were available. RESULTS Most conserved motifs observed in GPCR TMDs are also observed in the amino acid sequences of GPHR TMDs. Furthermore, most GPCR TMD conserved helix distortions are observed in our models of the structures of GPHR TMDs. Analysis of these structures has allowed us to propose a mechanism for activation of GPHR TMDs. CONCLUSIONS Insight into the mechanism of activation of the TSHR by both TSH and TSHR autoantibodies is likely to be useful in the development of new treatments for Graves' disease.
Collapse
Affiliation(s)
| | - Jane Sanders
- FIRS Laboratories, RSR Ltd, Parc Ty Glas, Llanishen, Cardiff, CF14 5DU, UK
| | - Jadwiga Furmaniak
- FIRS Laboratories, RSR Ltd, Parc Ty Glas, Llanishen, Cardiff, CF14 5DU, UK
| | - Bernard Rees Smith
- FIRS Laboratories, RSR Ltd, Parc Ty Glas, Llanishen, Cardiff, CF14 5DU, UK.
| |
Collapse
|
4
|
Garcia GL, Dong M, Miller LJ. Differential determinants for coupling of distinct G proteins with the class B secretin receptor. Am J Physiol Cell Physiol 2012; 302:C1202-12. [PMID: 22277758 DOI: 10.1152/ajpcell.00273.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The secretin receptor is a prototypic class B G protein-coupled receptor that is activated by binding of its natural peptide ligand. The signaling effects of this receptor are mediated by coupling with Gs, which activates cAMP production, and Gq, which activates intracellular calcium mobilization. We have explored the molecular basis for the coupling of each of these G proteins to this receptor using systematic site-directed mutagenesis of key residues within each of the intracellular loop regions, and studying ligand binding and secretin-stimulated cAMP and calcium responses. Mutation of a conserved histidine in the first intracellular loop (H157A and H157R) markedly reduced cell surface expression, resulting in marked reduction in cAMP and elimination of measurable calcium responses. Mutation of an arginine (R153A) in the first intracellular loop reduced calcium, but not cAMP responses. Mutation of a dibasic motif in the second intracellular loop (R231A/K232A) had no significant effects on any measured responses. Mutations in the third intracellular loop involving adjacent lysine and leucine residues (K302A/L303A) or two arginine residues separated by a leucine and an alanine (R318A/R321A) significantly reduced cAMP responses, while the latter also reduced calcium responses. Additive effects were elicited by combining the effective mutations, while combining all the effective mutations resulted in a construct that continued to bind secretin normally, but that elicited no significant cAMP or calcium responses. These data suggest that, while some receptor determinants are clearly shared, there are also distinct determinants for coupling with each of these G proteins.
Collapse
Affiliation(s)
- Gene L Garcia
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ 85259, USA
| | | | | |
Collapse
|
5
|
Bosch-Presegué L, Ramon E, Toledo D, Cordomí A, Garriga P. Alterations in the photoactivation pathway of rhodopsin mutants associated with retinitis pigmentosa. FEBS J 2011; 278:1493-505. [DOI: 10.1111/j.1742-4658.2011.08066.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
6
|
Orban T, Gupta S, Palczewski K, Chance MR. Visualizing water molecules in transmembrane proteins using radiolytic labeling methods. Biochemistry 2010; 49:827-34. [PMID: 20047303 DOI: 10.1021/bi901889t] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Essential to cells and their organelles, water is both shuttled to where it is needed and trapped within cellular compartments and structures. Moreover, ordered waters within protein structures often colocalize with strategically placed polar or charged groups critical for protein function, yet it is unclear if these ordered water molecules provide structural stabilization, mediate conformational changes in signaling, neutralize charged residues, or carry out a combination of all these functions. Structures of many integral membrane proteins, including G protein-coupled receptors (GPCRs), reveal the presence of ordered water molecules that may act like prosthetic groups in a manner quite unlike bulk water. Identification of "ordered" waters within a crystalline protein structure requires sufficient occupancy of water to enable its detection in the protein's X-ray diffraction pattern, and thus, the observed waters likely represent a subset of tightly bound functional waters. In this review, we highlight recent studies that suggest the structures of ordered waters within GPCRs are as conserved (and thus as important) as conserved side chains. In addition, methods of radiolysis, coupled to structural mass spectrometry (protein footprinting), reveal dynamic changes in water structure that mediate transmembrane signaling. The idea of water as a prosthetic group mediating chemical reaction dynamics is not new in fields such as catalysis. However, the concept of water as a mediator of conformational dynamics in signaling is just emerging, because of advances in both crystallographic structure determination and new methods of protein footprinting. Although oil and water do not mix, understanding the roles of water is essential to understanding the function of membrane proteins.
Collapse
Affiliation(s)
- Tivadar Orban
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106-4965, USA
| | | | | | | |
Collapse
|
7
|
Yan F, Bikbulatov RV, Mocanu V, Dicheva N, Parker CE, Wetsel WC, Mosier PD, Westkaemper RB, Allen JA, Zjawiony JK, Roth BL. Structure-based design, synthesis, and biochemical and pharmacological characterization of novel salvinorin A analogues as active state probes of the kappa-opioid receptor. Biochemistry 2009; 48:6898-908. [PMID: 19555087 DOI: 10.1021/bi900605n] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Salvinorin A, the most potent naturally occurring hallucinogen, has attracted an increasing amount of attention since the kappa-opioid receptor (KOR) was identified as its principal molecular target by us [Roth, B. L., et al. (2002) Proc. Natl. Acad. Sci. U.S.A. 99, 11934-11939]. Here we report the design, synthesis, and biochemical characterization of novel, irreversible, salvinorin A-derived ligands suitable as active state probes of the KOR. On the basis of prior substituted cysteine accessibility and molecular modeling studies, C315(7.38) was chosen as a potential anchoring point for covalent labeling of salvinorin A-derived ligands. Automated docking of a series of potential covalently bound ligands suggested that either a haloacetate moiety or other similar electrophilic groups could irreversibly bind with C315(7.38). 22-Thiocyanatosalvinorin A (RB-64) and 22-chlorosalvinorin A (RB-48) were both found to be extraordinarily potent and selective KOR agonists in vitro and in vivo. As predicted on the basis of molecular modeling studies, RB-64 induced wash-resistant inhibition of binding with a strict requirement for a free cysteine in or near the binding pocket. Mass spectrometry (MS) studies utilizing synthetic KOR peptides and RB-64 supported the hypothesis that the anchoring residue was C315(7.38) and suggested one biochemical mechanism for covalent binding. These studies provide direct evidence of the presence of a free cysteine in the agonist-bound state of the KOR and provide novel insights into the mechanism by which salvinorin A binds to and activates the KOR.
Collapse
Affiliation(s)
- Feng Yan
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Holleran BJ, Domazet I, Beaulieu ME, Yan LP, Guillemette G, Lavigne P, Escher E, Leduc R. Identification of transmembrane domain 6 & 7 residues that contribute to the binding pocket of the urotensin II receptor. Biochem Pharmacol 2009; 77:1374-82. [DOI: 10.1016/j.bcp.2009.01.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 01/20/2009] [Accepted: 01/21/2009] [Indexed: 11/16/2022]
|
9
|
Kane BE, McCurdy CR, Ferguson DM. Toward a Structure-Based Model of Salvinorin A Recognition of the κ-Opioid Receptor. J Med Chem 2008; 51:1824-30. [DOI: 10.1021/jm701040v] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Brian E. Kane
- Department of Medicinal Chemistry and Center for Drug Design, University of Minnesota, Minneapolis, Minnesota 55455 and Department of Medicinal Chemistry, University of Mississippi, University, Mississippi 38677
| | - Christopher R. McCurdy
- Department of Medicinal Chemistry and Center for Drug Design, University of Minnesota, Minneapolis, Minnesota 55455 and Department of Medicinal Chemistry, University of Mississippi, University, Mississippi 38677
| | - David M. Ferguson
- Department of Medicinal Chemistry and Center for Drug Design, University of Minnesota, Minneapolis, Minnesota 55455 and Department of Medicinal Chemistry, University of Mississippi, University, Mississippi 38677
| |
Collapse
|
10
|
Bakker RA, Jongejan A, Sansuk K, Hacksell U, Timmerman H, Brann MR, Weiner DM, Pardo L, Leurs R. Constitutively active mutants of the histamine H1 receptor suggest a conserved hydrophobic asparagine-cage that constrains the activation of class A G protein-coupled receptors. Mol Pharmacol 2007; 73:94-103. [PMID: 17959710 DOI: 10.1124/mol.107.038547] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to create and characterize constitutively active mutant (CAM) histamine H(1) receptors (H(1)R) using random mutagenesis methods to further investigate the activation process of the rhodopsin-like family of G protein-coupled receptors (GPCRs). This approach identified position 6.40 in TM 6 as a "hot spot" because mutation of Ile6.40(420) either to Glu, Gly, Ala, Arg, Lys, or Ser resulted in highly active CAM H(1)Rs, for which almost no histamine-induced receptor activation response could be detected. The highly conserved hydrophobic amino acid at position 6.40 defines, in a computational model of the H(1)R, the asparagine cage motif that restrains the side chain of Asn7.49 of the NPxxY motif toward transmembrane domain (TM 6) in the inactive state of the receptor. Mutation of the asparagine cage into Ala or Gly, removing the interfering bulky constraints, increases the constitutive activity of the receptor. The fact that the Ile6.40(420)Arg/Lys/Glu mutant receptors are highly active CAM H(1)Rs leads us to suggest that a positively charged residue, presumably the highly conserved Arg3.50 from the DRY motif, interacts in a direct or an indirect (through other side chains or/and internal water molecules) manner with the acidic Asp2.50..Asn7.49 pair for receptor activation.
Collapse
Affiliation(s)
- Remko A Bakker
- Leiden/Amsterdam Center for Drug Research, Department of Medicinal Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Stewart AJ, Sellar R, Wilson DJ, Millar RP, Lu ZL. Identification of a Novel Ligand Binding Residue Arg38(1.35)in the Human Gonadotropin-Releasing Hormone Receptor. Mol Pharmacol 2007; 73:75-81. [DOI: 10.1124/mol.107.040816] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
12
|
Pardo L, Deupi X, Dölker N, López-Rodríguez ML, Campillo M. The role of internal water molecules in the structure and function of the rhodopsin family of G protein-coupled receptors. Chembiochem 2007; 8:19-24. [PMID: 17173267 DOI: 10.1002/cbic.200600429] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Leonardo Pardo
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| | | | | | | | | |
Collapse
|
13
|
Smit MJ, Vischer HF, Bakker RA, Jongejan A, Timmerman H, Pardo L, Leurs R. Pharmacogenomic and Structural Analysis of Constitutive G Protein–Coupled Receptor Activity. Annu Rev Pharmacol Toxicol 2007; 47:53-87. [PMID: 17029567 DOI: 10.1146/annurev.pharmtox.47.120505.105126] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
G protein-coupled receptors (GPCRs) respond to a chemically diverse plethora of signal transduction molecules. The notion that GPCRs also signal without an external chemical trigger, i.e., in a constitutive or spontaneous manner, resulted in a paradigm shift in the field of GPCR pharmacology. The discovery of constitutive GPCR activity and the fact that GPCR binding and signaling can be strongly affected by a single point mutation drew attention to the evolving area of GPCR pharmacogenomics. For a variety of GPCRs, point mutations have been convincingly linked to human disease. Mutations within conserved motifs, known to be involved in GPCR activation, might explain the properties of some naturally occurring, constitutively active GPCR variants linked to disease. In this review, we provide a brief historical introduction to the concept of constitutive receptor activity and the pharmacogenomic and structural aspects of constitutive receptor activity.
Collapse
Affiliation(s)
- Martine J Smit
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Vrije Universiteit, Faculty of Sciences, Department of Chemistry, 1081 HV Amsterdam, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
14
|
Chen Y, Chen C, Liu-Chen LY. Dynorphin peptides differentially regulate the human kappa opioid receptor. Life Sci 2007; 80:1439-48. [PMID: 17316701 PMCID: PMC2696490 DOI: 10.1016/j.lfs.2007.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 01/01/2007] [Accepted: 01/06/2007] [Indexed: 10/23/2022]
Abstract
Dynorphins, endogenous peptides for the kappa opioid receptor, play important roles in many physiological and pathological functions. Here, we examined how prolonged treatment with three major prodynorphin peptides, dynorphin A (1-17) (Dyn A), dynorphin B (1-13) (Dyn B) and alpha-neoendorphin (alpha-Neo), regulated the human kappa opioid receptor (hKOR) stably expressed in Chinese hamster ovary (CHO) cells. Results from receptor binding and [(35)S]GTPgammaS binding assays showed that these peptides were potent full agonists of the hKOR with comparable receptor reserve and intrinsic efficacy to stimulate G proteins. A 4-h incubation with alpha-Neo at a concentration of approximately 600xEC(50) value (from [(35)S]GTPgammaS binding) resulted in receptor down-regulation to a much lower extent than the incubation with Dyn A and Dyn B at comparable concentrations ( approximately 10% vs. approximately 65%). Extending incubation period and increasing concentrations did not significantly affect the difference. The plateau level of alpha-Neo-mediated receptor internalization (30 min) was significantly less than those of Dyn A and Dyn B. Omission of the serum from the incubation medium or addition of peptidase inhibitors into the serum-containing medium enhanced alpha-Neo-, but not Dyn A- or Dyn B-, mediated receptor down-regulation and internalization; however, the degrees of alpha-Neo-induced adaptations were still significantly less than those of Dyn A and Dyn B. Thus, these endogenous peptides differentially regulate KOR after activating the receptor with similar receptor occupancy and intrinsic efficacy. Both stability in the presence of serum and intrinsic capacity to promote receptor adaptation play roles in the observed discrepancy among the dynorphin peptides.
Collapse
Affiliation(s)
- Yong Chen
- Department of Pharmacology and Center for Substance Abuse Research, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, PA 19140, U.S.A
| | | | | |
Collapse
|
15
|
Chapter 12 Principles of G-Protein Coupled Receptor Modeling for Drug Discovery. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1574-1400(07)03012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
16
|
Abstract
This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
| | | |
Collapse
|
17
|
Vortherms TA, Mosier PD, Westkaemper RB, Roth BL. Differential helical orientations among related G protein-coupled receptors provide a novel mechanism for selectivity. Studies with salvinorin A and the kappa-opioid receptor. J Biol Chem 2006; 282:3146-56. [PMID: 17121830 DOI: 10.1074/jbc.m609264200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Salvinorin A, the active component of the hallucinogenic sage Salvia divinorum, is an apparently selective and highly potent kappa-opioid receptor (KOR) agonist. Salvinorin A is unique among ligands for peptidergic G protein-coupled receptors in being nonnitrogenous and lipid-like in character. To examine the molecular basis for the subtype-selective binding of salvinorin A, we utilized an integrated approach using chimeric opioid receptors, site-directed mutagenesis, the substituted cysteine accessibility method, and molecular modeling and dynamics studies. We discovered that helix 2 is required for salvinorin A binding to KOR and that two residues (Val-108(2.53) and Val-118(2.63)) confer subtype selectivity. Intriguingly, molecular modeling studies predicted that these loci exhibit an indirect effect on salvinorin A binding, presumably through rotation of helix 2. Significantly, and in agreement with our in silico predictions, substituted cysteine accessibility method analysis of helix 2 comparing KOR and the delta-opioid receptor, which has negligible affinity for salvinorin A, revealed that residues known to be important for salvinorin A binding exhibit a differential pattern of water accessibility. These findings imply that differences in the helical orientation of helix 2 are critical for the selectivity of salvinorin A binding to KOR and provide a structurally novel basis for ligand selectivity.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Binding Sites
- Cell Line
- Diterpenes/metabolism
- Diterpenes, Clerodane
- Genetic Vectors
- Hallucinogens/metabolism
- Humans
- Kidney
- Kinetics
- Mice
- Models, Molecular
- Mutagenesis, Site-Directed
- Protein Conformation
- Radioligand Assay
- Receptors, G-Protein-Coupled/chemistry
- Receptors, Opioid, kappa/chemistry
- Receptors, Opioid, kappa/genetics
- Receptors, Opioid, kappa/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
Collapse
Affiliation(s)
- Timothy A Vortherms
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
| | | | | | | |
Collapse
|
18
|
Martinelli A, Tuccinardi T. An overview of recent developments in GPCR modelling: methods and validation. Expert Opin Drug Discov 2006; 1:459-76. [DOI: 10.1517/17460441.1.5.459] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
19
|
Chen Y, Chen C, Wang Y, Liu-Chen LY. Ligands Regulate Cell Surface Level of the Human κ Opioid Receptor by Activation-Induced Down-Regulation and Pharmacological Chaperone-Mediated Enhancement: Differential Effects of Nonpeptide and Peptide Agonists. J Pharmacol Exp Ther 2006; 319:765-75. [PMID: 16882876 DOI: 10.1124/jpet.106.107987] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Two peptide agonists, eight nonpeptide agonists, and five nonpeptide antagonists were evaluated for their capacity to regulate FLAG (DYKDDDDK)-tagged human kappa opioid receptors (hKORs) stably expressed in Chinese hamster ovary cells after incubation for 4 h with a ligand at a concentration approximately 1000-fold of its EC(50) (agonist) or K(i) (antagonist) value. Dynorphins A and B decreased the fully glycosylated mature form (55-kDa) of FLAG-hKOR by 70%, whereas nonpeptide full agonists [2-(3,4-dichlorophenyl)-N-methyl-N-[(2R)-2-pyrrolidin-1-ylcyclohexyl-]acetamide (U50,488H), 17-cyclopropylmethyl-3,14-dihydroxy-4,5-epoxy-6-[N-methyl-trans-3-(3-furyl) acrylamido] morphinan hydrochloride (TRK-820), ethylketocyclazocine, bremazocine, asimadoline, and (RS)-[3-[1-[[(3,4-dichlorophenyl)acetyl]-methylamino]-2-(1-pyrrolidinyl)ethyl]phenoxy] acetic acid hydrochloride (ICI 204,448) caused 10-30% decreases. In contrast, pentazocine (partial agonist) and etorphine (full agonist) up-regulated by approximately 15 and 25%, respectively. The antagonists naloxone and norbinaltorphimine also significantly increased the 55-kDa receptor, whereas selective mu, delta, and D(1) receptor antagonists had no effect. Naloxone up-regulated the receptor concentration- and time-dependently and enhanced the receptor maturation extent, without affecting its turnover. Treatment with brefeldin A (BFA), which disrupts Golgi, resulted in generation of a 51-kDa form that resided intracellularly. Naloxone up-regulated the new species, indicating that its action site is in the endoplasmic reticulum as a pharmacological chaperone. After treatment with BFA, all nonpeptide agonists up-regulated the 51-kDa form, whereas dynorphins A and B did not, indicating that nonpeptide agonists act as pharmacological chaperones, but peptide agonists do not. BFA treatment enhanced down-regulation of the cell surface receptor induced by nonpeptide agonists, but not that by peptide agonists, and unmasked etorphine- and pentazocine-mediated receptor down-regulation. These results demonstrate that ligands have dual effects on receptor levels: enhancement by chaperone-like effects and agonist-promoted down-regulation, and the net effect reflects the algebraic sum of the two.
Collapse
Affiliation(s)
- Yong Chen
- Department of Pharmacology, Temple University School of Medicine, 3420 N. Broad St., Philadelphia, PA 19140, USA
| | | | | | | |
Collapse
|