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Abstract
Defining G protein-coupled receptor ligand efficacy and biased agonism in precise chemical terms is one challenge posed by the current structural data that exists for this receptor family. Concepts classically used for understanding enzymes and other nonreceptor proteins may lead us in the right direction.
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152
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Belmonte SL, Blaxall BC. Conducting the G-protein Coupled Receptor (GPCR) Signaling Symphony in Cardiovascular Diseases: New Therapeutic Approaches. ACTA ACUST UNITED AC 2012; 9:e85-e90. [PMID: 23162605 DOI: 10.1016/j.ddmod.2012.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
G protein-coupled receptors (GPCRs) are a virtually ubiquitous class of membrane-bound receptors, which functionally couple hormone or neurotransmitter signals to physiological responses. Dysregulation of GPCR signaling contributes to the pathophysiology of a host of cardiovascular disorders. Pharmacological agents targeting GPCRs have been established as therapeutic options for decades. Nevertheless, the persistent burden of cardiovascular diseases necessitates improved treatments. To that end, exciting drug development efforts have begun to focus on novel compounds that discriminately activate particular GPCR signaling pathways.
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Affiliation(s)
- Stephen L Belmonte
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA
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153
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Grunbeck A, Huber T, Abrol R, Trzaskowski B, Goddard WA, Sakmar TP. Genetically encoded photo-cross-linkers map the binding site of an allosteric drug on a G protein-coupled receptor. ACS Chem Biol 2012; 7:967-72. [PMID: 22455376 DOI: 10.1021/cb300059z] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
G protein-coupled receptors (GPCRs) are dynamic membrane proteins that bind extracellular molecules to transduce signals. Although GPCRs represent the largest class of therapeutic targets, only a small percentage of their ligand-binding sites are precisely defined. Here we describe the novel application of targeted photo-cross-linking using unnatural amino acids to obtain structural information about the allosteric binding site of a small molecule drug, the CCR5-targeted HIV-1 co-receptor blocker maraviroc.
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Affiliation(s)
- Amy Grunbeck
- Laboratory of Molecular Biology & Biochemistry, The Rockefeller University, 1230 York Ave., New York, New York 10065, United States
| | - Thomas Huber
- Laboratory of Molecular Biology & Biochemistry, The Rockefeller University, 1230 York Ave., New York, New York 10065, United States
| | - Ravinder Abrol
- Materials and Process Simulation
Center (MC 139-74), California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, United States
| | - Bartosz Trzaskowski
- Materials and Process Simulation
Center (MC 139-74), California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, United States
| | - William A. Goddard
- Materials and Process Simulation
Center (MC 139-74), California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, United States
| | - Thomas P. Sakmar
- Laboratory of Molecular Biology & Biochemistry, The Rockefeller University, 1230 York Ave., New York, New York 10065, United States
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154
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Jacobson KA, Costanzi S. New insights for drug design from the X-ray crystallographic structures of G-protein-coupled receptors. Mol Pharmacol 2012; 82:361-71. [PMID: 22695719 DOI: 10.1124/mol.112.079335] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Methodological advances in X-ray crystallography have made possible the recent solution of X-ray structures of pharmaceutically important G protein-coupled receptors (GPCRs), including receptors for biogenic amines, peptides, a nucleoside, and a sphingolipid. These high-resolution structures have greatly increased our understanding of ligand recognition and receptor activation. Conformational changes associated with activation common to several receptors entail outward movements of the intracellular side of transmembrane helix 6 (TM6) and movements of TM5 toward TM6. Movements associated with specific agonists or receptors have also been described [e.g., extracellular loop (EL) 3 in the A(2A) adenosine receptor]. The binding sites of different receptors partly overlap but differ significantly in ligand orientation, depth, and breadth of contact areas in TM regions and the involvement of the ELs. A current challenge is how to use this structural information for the rational design of novel potent and selective ligands. For example, new chemotypes were discovered as antagonists of various GPCRs by subjecting chemical libraries to in silico docking in the X-ray structures. The vast majority of GPCR structures and their ligand complexes are still unsolved, and no structures are known outside of family A GPCRs. Molecular modeling, informed by supporting information from site-directed mutagenesis and structure-activity relationships, has been validated as a useful tool to extend structural insights to related GPCRs and to analyze docking of other ligands in already crystallized GPCRs.
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Affiliation(s)
- Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810, USA.
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155
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Janovick JA, Pogozheva ID, Mosberg HI, Cornea A, Conn PM. Rescue of misrouted GnRHR mutants reveals its constitutive activity. Mol Endocrinol 2012; 26:1179-88. [PMID: 22595961 DOI: 10.1210/me.2012-1089] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
G protein-coupled receptors (GPCR) play central roles in almost all physiological functions, and mutations in GPCR are responsible for over 30 hereditary diseases associated with loss or gain of receptor function. Gain of function mutants are frequently described as having constitutive activity (CA), that is, they activate effectors in the absence of agonist occupancy. Although many GPCR have mutants with CA, the GnRH receptor (GnRHR) was not, until 2010, associated with any CA mutants. The explanation for the failure to observe CA appears to be that the quality control system of the cell recognizes CA mutants of GnRHR as misfolded and retains them in the endoplasmic reticulum. In the present study, we identified several human (h)GnRHR mutants with substitutions in transmembrane helix 6 (F(272)K, F(272)Q, Y(284)F, C(279)A, and C(279)S) that demonstrate varying levels of CA after being rescued by pharmacoperones from different chemical classes and/or deletion of residue K(191), a modification that increases trafficking to the plasma membrane. The movement of the mutants from the endoplasmic reticulum (unrescued) to the plasma membrane (after rescue) is supported by confocal microscopy. Judging from the receptor-stimulated inositol phosphate production, mutants F(272)K and F(272)Q, after rescue, display the largest level of CA, an amount that is comparable with agonist-stimulated activation. Because mutations in other GPCR are, like the hGnRHR, scrutinized by the quality control system, this general approach may reveal CA in receptor mutants from other systems. A computer model of the hGnRHR and these mutants was used to evaluate the conformation associated with CA.
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Affiliation(s)
- Jo Ann Janovick
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006-3448, USA
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156
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Physiology and emerging biochemistry of the glucagon-like peptide-1 receptor. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:470851. [PMID: 22666230 PMCID: PMC3359799 DOI: 10.1155/2012/470851] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 01/25/2012] [Indexed: 12/16/2022]
Abstract
The glucagon-like peptide-1 (GLP-1) receptor is one of the best validated therapeutic targets for the treatment of type 2 diabetes mellitus (T2DM). Over several years, the accumulation of basic, translational, and clinical research helped define the physiologic roles of GLP-1 and its receptor in regulating glucose homeostasis and energy metabolism. These efforts provided much of the foundation for pharmaceutical development of the GLP-1 receptor peptide agonists, exenatide and liraglutide, as novel medicines for patients suffering from T2DM. Now, much attention is focused on better understanding the molecular mechanisms involved in ligand induced signaling of the GLP-1 receptor. For example, advancements in biophysical and structural biology techniques are being applied in attempts to more precisely determine ligand binding and receptor occupancy characteristics at the atomic level. These efforts should better inform three-dimensional modeling of the GLP-1 receptor that will help inspire more rational approaches to identify and optimize small molecule agonists or allosteric modulators targeting the GLP-1 receptor. This article reviews GLP-1 receptor physiology with an emphasis on GLP-1 induced signaling mechanisms in order to highlight new molecular strategies that help determine desired pharmacologic characteristics for guiding development of future nonpeptide GLP-1 receptor activators.
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157
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Wasserman SR, Koss JW, Sojitra ST, Morisco LL, Burley SK. Rapid-access, high-throughput synchrotron crystallography for drug discovery. Trends Pharmacol Sci 2012; 33:261-7. [PMID: 22521107 DOI: 10.1016/j.tips.2012.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 10/28/2022]
Abstract
Synchrotron X-ray sources provide the highest quality crystallographic data for structure-guided drug design. In general, industrial utilization of such sources has been intermittent and occasionally limited. The Lilly Research Laboratories Collaborative Access Team (LRL-CAT) beamline provides a unique alternative to traditional synchrotron use by pharmaceutical and biotechnology companies. Crystallographic experiments at LRL-CAT and the results therefrom are integrated directly into the drug discovery process, permitting structural data, including screening of fragment libraries, to be routinely and rapidly used on a daily basis as part of pharmaceutical lead discovery and optimization. Here we describe how LRL-CAT acquires and disseminates the results from protein crystallography to maximize their impact on the development of new potential medicines.
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Affiliation(s)
- Stephen R Wasserman
- LRL-CAT, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Building 438, Argonne, IL 60439, USA.
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158
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Drinovec L, Kubale V, Nøhr Larsen J, Vrecl M. Mathematical models for quantitative assessment of bioluminescence resonance energy transfer: application to seven transmembrane receptors oligomerization. Front Endocrinol (Lausanne) 2012; 3:104. [PMID: 22973259 PMCID: PMC3428587 DOI: 10.3389/fendo.2012.00104] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/08/2012] [Indexed: 11/24/2022] Open
Abstract
The idea that seven transmembrane receptors (7TMRs; also designated G-protein coupled receptors, GPCRs) might form dimers or higher order oligomeric complexes was formulated more than 20 years ago and has been intensively studied since then. In the last decade, bioluminescence resonance energy transfer (BRET) has been one of the most frequently used biophysical methods for studying 7TMRs oligomerization. This technique enables monitoring physical interactions between protein partners in living cells fused to donor and acceptor moieties. It relies on non-radiative transfer of energy between donor and acceptor, depending on their intermolecular distance (1-10 nm) and relative orientation. Results derived from BRET-based techniques are very persuasive; however, they need appropriate controls and critical interpretation. To overcome concerns about the specificity of BRET-derived results, a set of experiments has been proposed, including negative control with a non-interacting receptor or protein, BRET dilution, saturation, and competition assays. This article presents the theoretical background behind BRET assays, then outlines mathematical models for quantitative interpretation of BRET saturation and competition assay results, gives examples of their utilization and discusses the possibilities of quantitative analysis of data generated with other RET-based techniques.
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159
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Siderius M, Wal M, Scholten DJ, Smit MJ, Sakmar TP, Leurs R, de Graaf C. Unnatural amino acids for the study of chemokine receptor structure and dynamics. DRUG DISCOVERY TODAY. TECHNOLOGIES 2012; 9:e227-e314. [PMID: 24063744 DOI: 10.1016/j.ddtec.2012.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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160
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Herr DR. Potential use of G protein-coupled receptor-blocking monoclonal antibodies as therapeutic agents for cancers. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 297:45-81. [PMID: 22608557 DOI: 10.1016/b978-0-12-394308-8.00002-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The therapeutic use of monoclonal antibodies (mAbs) is the fastest growing area of pharmaceutical development and has enjoyed significant clinical success since approval of the first mAb drug in1984. However, despite significant effort, there are still no approved therapeutic mAbs directed against the largest and most attractive family of drug targets: G protein-coupled receptors (GPCRs). GPCRs regulate essentially all cellular processes, including those that are fundamental to cancer pathology, such as proliferation, survival/drug resistance, migration, differentiation, tissue invasion, and angiogenesis. Many different GPCR isoforms are enhanced or dysregulated in multiple tumor types, and several GPCRs have known oncogenic activity. With approximately 350 distinct GPCRs in the genome, these receptors provide a rich landscape for the design of effective, targeted therapies for cancer, a uniquely heterogeneous disease family. While the generation of selective, efficacious mAbs has been problematic for these structurally complex integral membrane proteins, progress in the development of immunotherapeutics has been made by several independent groups. This chapter provides an overview of the roles of GPCRs in cancer and describes the current state of the art of GPCR-targeted mAb drugs.
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Affiliation(s)
- Deron R Herr
- Expression Drug Designs, LLC, San Marcos, California, USA
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161
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de Graaf C, Kooistra AJ, Vischer HF, Katritch V, Kuijer M, Shiroishi M, Iwata S, Shimamura T, Stevens RC, de Esch IJP, Leurs R. Crystal structure-based virtual screening for fragment-like ligands of the human histamine H(1) receptor. J Med Chem 2011; 54:8195-206. [PMID: 22007643 DOI: 10.1021/jm2011589] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The recent crystal structure determinations of druggable class A G protein-coupled receptors (GPCRs) have opened up excellent opportunities in structure-based ligand discovery for this pharmaceutically important protein family. We have developed and validated a customized structure-based virtual fragment screening protocol against the recently determined human histamine H(1) receptor (H(1)R) crystal structure. The method combines molecular docking simulations with a protein-ligand interaction fingerprint (IFP) scoring method. The optimized in silico screening approach was successfully applied to identify a chemically diverse set of novel fragment-like (≤22 heavy atoms) H(1)R ligands with an exceptionally high hit rate of 73%. Of the 26 tested fragments, 19 compounds had affinities ranging from 10 μM to 6 nM. The current study shows the potential of in silico screening against GPCR crystal structures to explore novel, fragment-like GPCR ligand space.
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Affiliation(s)
- Chris de Graaf
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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