DOCSLIB.ORG

G Protein-Coupled Receptor Allosterism and Complexing

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
G Protein-Coupled Receptor Allosterism and Complexing 0031-6997/02/5402-323–374$7.00 PHARMACOLOGICAL REVIEWS Vol. 54, No. 2 Copyright © 2002 by The American Society for Pharmacology and Experimental Therapeutics 20202/986538 Pharmacol Rev 54:323–374, 2002 Printed in U.S.A G Protein-Coupled Receptor Allosterism and Complexing ARTHUR CHRISTOPOULOS AND TERRY KENAKIN Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia (A.C.); and 7TM Pharmacology Systems Research, Glaxo Smith-Kline Research and Development, Research Triangle Park, North Carolina (T.K.) This paper is available online at http://pharmrev.aspetjournals.org Abstract .............................................................................. 323 I. Introduction ........................................................................... 324 II. Allosteric receptor models of G protein-coupled receptors................................... 325 A. Historical perspective ............................................................... 325 1. Cooperativity in binding .......................................................... 325 2. Allosteric transitions: multistate models of receptor action ........................... 326 3. Allosteric interactions: ternary complex models ..................................... 327 B. Behavior of the ternary complex model ............................................... 332 C. The molecular nature of allosterism at G protein-coupled receptors ...................... 333 1. G protein-specific receptor conformations........................................... 334 Downloaded from 2. Ligand-specific receptor conformations ............................................. 336 III. Detecting allosteric interactions ......................................................... 338 A. Assays of radioligand binding ........................................................ 338 1. Equilibrium binding assays ....................................................... 338 2. Inhibition binding assays ......................................................... 339 by guest on June 7, 2018 3. Nonequilibrium (kinetic) studies................................................... 344 B. Assays of receptor function .......................................................... 348 1. Schild analysis .................................................................. 348 2. Additivity of concentration ratios .................................................. 348 3. Pharmacological resultant analysis ................................................ 350 C. Potential pitfalls.................................................................... 351 IV. Usefulness of allosteric modulators ...................................................... 352 V. Location of the allosteric site(s).......................................................... 354 A. Locks and keys ..................................................................... 354 B. Modulation by ions ................................................................. 355 C. Interactions at the receptor-G protein interface ........................................ 356 D. Extracellular allosteric sites ......................................................... 357 1. Multiple allosteric sites........................................................... 359 VI. Endogenous allosteric modulators ....................................................... 360 VII. G protein-coupled receptor complexing ................................................... 361 A. Receptor-receptor interactions........................................................ 362 B. Accessory proteins .................................................................. 364 VIII. Conclusions ........................................................................... 368 Acknowledgments ...................................................................... 368 References ............................................................................ 368 Abstract——G protein-coupled receptors (GPCRs) conformational change in the receptor protein trans- represent the largest family of cell-surface receptors. mitted between two topographically distinct binding These receptors are natural allosteric proteins be- sites, one for the agonist and another for the G protein. cause agonist-mediated signaling by GPCRs requires a It is now becoming increasingly recognized, however, that the agonist-bound GPCR can also form ternary Address correspondence to: Dr. Arthur Christopoulos, Department of complexes with other ligands or “accessory” proteins Pharmacology, University of Melbourne, Grattan Street, Parkville, Victo- and display altered binding and/or signaling proper- ria 3010, Australia. E-mail: [email protected] ties in relation to the binary agonist-receptor complex. 323 324 CHRISTOPOULOS AND KENAKIN Allosteric sites on GPCRs represent novel drug targets ric effects. Moreover, we provide an overview of the because allosteric modulators possess a number of current knowledge regarding the location of possible theoretical advantages over classic orthosteric li- allosteric sites on GPCRs and candidate endogenous gands, such as a ceiling level to the allosteric effect allosteric modulators. Finally, we discuss the poten- and a potential for greater GPCR subtype-selectivity. tial for allosteric effects arising from the formation of Because of the noncompetitive nature of allosteric GPCR oligomers or GPCRs complexed with accessory phenomena, the detection and quantification of such cellular proteins. It is proposed that the study of allo- effects often relies on a combination of equilibrium steric phenomena will become of progressively binding, nonequilibrium kinetic, and functional sig- greater import to the drug discovery process due to naling assays. This review discusses the development the advent of newer and more sensitive GPCR screen- and properties of allosteric receptor models for ing technologies. GPCRs and the detection and quantification of alloste- I. Introduction GPCR can be considered a potential binding site for biologically active molecules, both proteins and small A general property of all receptors is the ability to molecules such as drugs. It is a major premise of this interact with their endogenous ligands (hormones and review that a tripartite system composed of a ligand, a neurotransmitters) to alter cellular responsiveness GPRC, and an additional GPCR coupling partner repre- without changing the chemical nature of the ligand. This sents a general motif for ligand action at GPCRs extend- is in contrast to enzymes, where oftentimes a substrate ing beyond the G protein example. In other words, the is made to bind in an energetically unfavorable mode requisite interaction between topographically distinct that leads to its eventual modification. G protein-cou- binding sites on a GPCR to effect change in cellular pled receptors (GPCRs) constitute the largest superfam- function identifies these receptors as natural allosteric ily of receptors and, not surprisingly, mediate the ma- proteins. jority of transmembrane signal transduction in living Drugs have traditionally been discovered through the cells. These receptors respond to a wide range of rela- screening of numerous chemical structures on a biolog- tively small and structurally diverse chemicals such as ical system. The greater the number of structures tested, biogenic amines, peptides, hormones, and even light with global changes in receptor conformation that then the greater is the probability of detecting a biologically lead to larger scale protein-protein interactions. active ligand. Throughout this process, it is clear that Traditionally, the unifying feature of GPCRs has been the type of receptor screen employed to detect biologi- their interaction with G protein(s) to transduce stimuli cally active molecules will greatly define the types of imparted to the receptor from the extracellular environ- molecules detected. Thus, if the tracer molecule in the ment to the intracellular response machinery of the cell. screen is a radioligand, then the ligands most readly Implicit in this mechanism, therefore, is the fact that the detected by that screen will be those that obstruct the intracellular contact points on the GPCR recognized by access of the radioligand to its specific binding site. the G protein are necessarily distinct from the extracel- Notably, the current emphasis away from radioligand lular domains used by endogenous ligands. The lateral binding and toward high throughput functional screen- translocation of GPCRs in the cell membrane to interact ing is beginning to reveal ligands that can change bio- with their cognate G protein(s) is the best known exam- logical function without exerting apparent effects on ple of GPCR-protein interaction, but it is by no means radioligand binding. It is possible that such ligands are the only such example, because additional protein cou- not interacting with the classic, agonist-binding domain pling partners are now being rapidly identified for the of the receptor but rather with other topographically GPCR superfamily (vide infra). The entire surface of a distinct domains. This raises an interesting philosophical point in drug discovery, namely the current paucity of allosteric li- 1 Abbreviations: GPCR, G protein-coupled receptor; ICI-174,864, N,N-diallyl-Tyr-Aib-Aib-Phe-Leu-OH; NalBzOH, naloxone benzoyl- gands in the known population of biologically active hydrazone; PI, phosphoinositide; CTC, cubic ternary complex; ETC, molecules. On one hand it could be assumed that this extended ternary
Load more

Recommended publications
  • International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification
    0031-6997/03/5504-597–606$7.00 PHARMACOLOGICAL REVIEWS Vol. 55, No. 4 Copyright © 2003 by The American Society for Pharmacology and Experimental Therapeutics 30404/1114803 Pharmacol Rev 55:597–606, 2003 Printed in U.S.A International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. XXXVIII. Update on Terms and Symbols in Quantitative Pharmacology RICHARD R. NEUBIG, MICHAEL SPEDDING, TERRY KENAKIN, AND ARTHUR CHRISTOPOULOS Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (R.R.N.); Institute de Recherches Internationales Servier, Neuilly sur Seine, France (M.S.); Systems Research, GlaxoSmithKline Research and Development, Research Triangle Park, North Carolina (T.K.); and Department of Pharmacology, University of Melbourne, Parkville, Australia (A.C.) Abstract ............................................................................... 597 I. Introduction............................................................................ 597 II. Working definition of a receptor .......................................................... 598 III. Use of drugs in definition of receptors or of signaling pathways ............................. 598 A. The expression of amount of drug: concentration and dose ............................... 598 1. Concentration..................................................................... 598 2. Dose. ............................................................................ 598 B. General terms used to describe drug action ...........................................
    [Show full text]
  • International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. XXXVIII. Update on Terms and Symbols in Quantitative Pharmacology
    0031-6997/03/5504-597–606$7.00 PHARMACOLOGICAL REVIEWS Vol. 55, No. 4 Copyright © 2003 by The American Society for Pharmacology and Experimental Therapeutics 30404/1114803 Pharmacol Rev 55:597–606, 2003 Printed in U.S.A International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. XXXVIII. Update on Terms and Symbols in Quantitative Pharmacology RICHARD R. NEUBIG, MICHAEL SPEDDING, TERRY KENAKIN, AND ARTHUR CHRISTOPOULOS Department of Pharmacology, University of Michigan, Ann Arbor, Michigan (R.R.N.); Institute de Recherches Internationales Servier, Neuilly sur Seine, France (M.S.); Systems Research, GlaxoSmithKline Research and Development, Research Triangle Park, North Carolina (T.K.); and Department of Pharmacology, University of Melbourne, Parkville, Australia (A.C.) Abstract ............................................................................... 597 I. Introduction............................................................................ 597 II. Working definition of a receptor .......................................................... 598 III. Use of drugs in definition of receptors or of signaling pathways ............................. 598 A. The expression of amount of drug: concentration and dose ............................... 598 Downloaded from 1. Concentration..................................................................... 598 2. Dose. ............................................................................ 598 B. General terms used to describe drug action ...........................................
    [Show full text]
  • Matters of Receptor Conformation
    Inverse, protean, and ligand-selective agonism: matters of receptor conformation TERRY KENAKIN Department of Receptor Biochemistry, Glaxo SmithKline Research and Development, Research Triangle Park, North Carolina 27709, USA ABSTRACT Concepts regarding the mechanisms by allosteric interaction resulted in an alteration of the which drugs activate receptors to produce physiological affinity of the receptor for the radiolabel. With the response have progressed beyond considering the re- technological advances enabling high-throughput func- ceptor as a simple on-off switch. Current evidence tional receptor screens should come an increase in the suggests that the idea that agonists produce only vary- types of GPCR ligands in the new millennium. This will ing degrees of receptor activation is obsolete and must result in an increase in the number of allosteric ligands be reconciled with data to show that agonist efficacy has (modulators, agonists, enhancers) that modify receptor texture as well as magnitude. Thus, agonists can block function without necessarily modifying steric access of system constitutive response (inverse agonists), behave the endogenous ligands to the receptor. Therefore, the as positive and inverse agonists on the same receptor changing mode of high-throughput screening can be (protean agonists), and differ in the stimulus pattern predicted to lead to an increase in the texture of drug they produce in physiological systems (ligand-selective types for GPCRs. Another reason for the increasing agonists). The molecular mechanism for this seemingly number of drug targets is increased knowledge of diverse array of activities is the same, namely, the GPCR behavior in cellular systems. This has led to the selective microaffinity of ligands for different confor- discovery of inverse agonism.
    [Show full text]
  • A Single Unified Model for Fitting Simple to Complex Receptor Response Data
    www.nature.com/scientificreports OPEN A single unifed model for ftting simple to complex receptor response data Peter Buchwald The ftting of complex receptor-response data where fractional response and occupancy do not match is challenging. They encompass important cases including (a) the presence of “receptor reserve” and/or partial agonism, (b) multiple responses assessed at diferent vantage points along a pathway, (c) responses that are diferent along diverging downstream pathways (biased agonism), and (d) constitutive activity. For these, simple models such as the well-known Clark or Hill equations cannot be used. Those that can, such as the operational (Black&Lef) model, do not provide a unifed approach, have multiple nonintuitive parameters that are challenging to ft in well-defned manner, have difculties incorporating binding data, and cannot be reduced or connected to simpler forms. We have recently introduced a quantitative receptor model (SABRE) that includes parameters for Signal Amplifcation (γ), Binding afnity (Kd), Receptor activation Efcacy (ε), and constitutive activity (εR0). It provides a single equation to ft complex cases within a full two-state framework with the possibility of incorporating receptor occupancy data (i.e., experimental Kds). Simpler cases can be ft by using consecutively reduced forms obtained by constraining parameters to specifc values, e.g., εR0 = 0: no constitutive activity, γ = 1: no amplifcation (Emax-type ftting), and ε = 1: no partial agonism (Clark equation). Here, a Hill-type extension is introduced (n ≠ 1), and simulated and experimental receptor- response data from simple to increasingly complex cases are ftted within the unifed framework of SABRE with diferently constrained parameters.
    [Show full text]
  • Review of Pharmacologic Receptors and Advances
    https://doi.org/10.31871/WJIR.8.6.8 World Journal of Innovative Research (WJIR) ISSN: 2454-8236, Volume-8, Issue-6, June 2020 Pages 91-100 Review of Pharmacologic Receptors and Advances Chukwu LC, Ekenjoku AJ, Okam P.C, Ohadoma SC, Olisa CL membrane as well as the inside of the cell. They can that can Abstract— The effects of most drugs result from their bind to a ligand and get triggered to alter their shape or interaction with macromolecular components of the same activity giving rise to a signal cascade of intracellular organism. These interactions have the capacity to alter the molecules - the second messengers, which, ultimately, results functions of the pertinent component and thereby initiate a in some change in the cell’s function (Tanner Marshall et al, cascade of biochemical and physiological changes that are characteristic of the response to the drug in question. The term 2020). receptor therefore, denotes the component of the organism with Receptors are specialized target macromolecules present which the chemical agent is presumed to interact. on the cell surface or intracellularly. Receptors bind drugs This drug-receptor is closely related to the enzyme-substrate and initiate events leading to alterations in biochemical complexes or that of antigen and antibody; these interactions and/or biophysical activity of a cell, and consequently, the have many common features, perhaps the most noteworthy function of an organ. Drugs may interact with receptors in being specificity of the receptor for a given ligand. However, the receptor not only has the ability to recognize a ligand, but can many different ways and may exert their effects.
    [Show full text]
  • Review Incorporating Receptor Theory in Mechanism-Based Pharmacokinetic-Pharmacodynamic (PK-PD) Modeling
    Drug Metab. Pharmacokinet. 24 (1): 3–15 (2009). Review Incorporating Receptor Theory in Mechanism-Based Pharmacokinetic-Pharmacodynamic (PK-PD) Modeling Bart A. PLOEGER1,3,*,PietH.vanderGRAAF2 and Meindert DANHOF1,3 1LAP&P Consultants BV, Leiden, The Netherlands 2Pfizer, Department of Pharmacokinetics, Dynamics, and Metabolism (PDM), Sandwich, United Kingdom 3Leiden-Amsterdam Center for Drug Research, Division of Pharmacology, University of Leiden, Leiden, The Netherlands Full text of this paper is available at http://www.jstage.jst.go.jp/browse/dmpk Summary: Pharmacokinetic-Pharmacodynamic (PK-PD) modeling helps to better understand drug efficacy and safety and has, therefore, become a powerful tool in the learning-confirming cycles of drug-development. In translational drug research, mechanism-based PK-PD modeling has been recognized as a tool for bringing forward early insights in drug efficacy and safety into the clinical development. These models differ from descriptive PK-PD models in that they quantitatively characterize specific processes in the causal chain be- tween drug administration and effect. This includes target site distribution, binding and activation, phar- macodynamic interactions, transduction and homeostatic feedback mechanisms. Compared to descriptive models mechanism-based PK-PD models that utilize receptor theory concepts for characterization of target binding and target activation processes have improved properties for extrapolation and prediction. In this respect, receptor theory constitutes the basis for 1) prediction of in vivo drug concentration-effect relation- ships and 2) characterization of target association-dissociation kinetics as determinants of hysteresis in the time course of the drug effect. This approach intrinsically distinguishes drug- and system specific parameters explicitly, allowing accurate extrapolation from in vitro to in vivo and across species.
    [Show full text]
  • 1 Pharmacogenomic and Structural Analysis of Constitutive G-Protein
    Pharmacogenomic and structural analysis of constitutive G-protein coupled receptor activity Martine J. Smit1, Henry F. Vischer1, Remko A. Bakker1,3, Aldo Jongejan1, Henk Timmerman1, Leonardo Pardo2 and Rob Leurs1 1Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Vrije Universiteit, Faculty of Science, Department of Chemistry, de Boelelaan 1083, 1081 HV Amsterdam, the Netherlands 2Laboratorio de Medicina Computacional, Unidad de Bioestadistica, Facultad de Medicina, Universidad Autonoma de Barcelona, Barcelona, Spain. 3Current address Boehringer Ingelheim Pharma GmbH & Co. KG 88397 Biberach, Germany. Keywords G-protein coupled receptors; constitutive activity; inverse agonism 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. With the recognition of constitutive GPCR activity and the fact that GPCR binding and signaling can be strongly affected by a single point mutation, GPCR pharmacogenomics obtained a lot of attention. 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. A brief history historical introduction to the present concept of constitutive receptor activity is given and the pharmacogenomic and the structural aspects of constitutive receptor activity are described. 1. Introduction G-protein coupled receptors (GPCRs) form one of the most versatile families of proteins to respond to the chemically diverse plethora of signal transduction molecules.
    [Show full text]
  • THE CONTRIBUTION of K+ ION CHANNELS and the Ca2+-PERMEABLE TRPM8 CHANNEL to BREAST CANCER CELL PROLIFERATION
    THE CONTRIBUTION OF K+ ION CHANNELS AND THE Ca2+-PERMEABLE TRPM8 CHANNEL TO BREAST CANCER CELL PROLIFERATION. by Jeremy W Roy Submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Dalhousie University Halifax, Nova Scotia October 2010 © Copyright by Jeremy W Roy, 2010 DALHOUSIE UNIVERSITY DEPARTMENT OF PHYSIOLOGY AND BIOPHYSICS The undersigned hereby certify that they have read and recommend to the Faculty of Graduate Studies for acceptance a thesis entitled “THE CONTRIBUTION OF K+ ION CHANNELS AND THE Ca2+-PERMEABLE TRPM8 CHANNEL TO BREAST CANCER CELL PROLIFERATION” by Jeremy W Roy in partial fulfilment of the requirements for the degree of Doctor of Philosophy. Dated: October 26, 2010 Supervisor: _______________________________ Readers: _______________________________ _______________________________ _______________________________ ii DALHOUSIE UNIVERSITY DATE: October 26, 2010 AUTHOR: Jeremy W Roy TITLE: THE CONTRIBUTION OF K+ ION CHANNELS AND THE Ca2+- PERMEABLE TRPM8 CHANNEL TO BREAST CANCER CELL PROLIFERATION. DEPARTMENT OR SCHOOL: Department of Physiology and Biophysics DEGREE: PhD CONVOCATION: May YEAR: 2011 Permission is herewith granted to Dalhousie University to circulate and to have copied for non-commercial purposes, at its discretion, the above title upon the request of individuals or institutions. _______________________________ Signature of Author The author reserves other publication rights, and neither the thesis nor extensive extracts from it may be printed or otherwise reproduced without the author‟s written permission. The author attests that permission has been obtained for the use of any copyrighted material appearing in the thesis (other than the brief excerpts requiring only proper acknowledgement in scholarly writing), and that all such use is clearly acknowledged.
    [Show full text]
  • Pharmacodynamics: the Study of Drug Action
    © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION ✜ Objectives 2 After completing this chapter, the reader should be able to Pharmacodynamics: ■ Describe the various mechanisms in which drug mol- The Study of Drug Action ecules elicit their effects. ■ Illustrate the effects of receptor-mediated agonists Ronald M. Dick, PhD, RPh and antagonists. ■ Describe the differences between competitive, non- competitive, and allosteric antagonism. ■ Compare and contrast the differences and similarities between ionophoric and metabophoric receptors. ■ Compare current and historic mechanisms of anes- thetic action in the body. ❚ Introduction behind theory, and it would take the introduction of the b The branch of pharmacology that relates drug concentra- -adrenergic antagonist, propranolol, in 1965 to provide tion to biologic effect is known as pharmacodynamics. the data necessary to completely convince the scientific Major goals of this area of study are determining the proper community that receptors truly exist. Since then, specific dose to administer to elicit the desired effect while avoiding molecular targets of action have been identified for nearly toxicity. Although pharmacokinetics can be used to deter- all drugs, and evidence for the receptor theory continues mine dosing requirements necessary to maintain a particu- to grow. However, a few drugs, such as osmotic laxatives, lar drug concentration, it is the relationship between drug do not appear to require receptor interactions to provide concentration and effect that ultimately decides appropri- their effects. Another class of compounds of particular ate dosing. The ultimate goal is to maintain a drug con- interest, the general anesthetics, apparently exhibit such a centration within the proper therapeutic window thereby wide array of effects that some in the scientific community avoiding toxicity while providing an adequate concentra- still do not subscribe to the idea that a receptor-mediated tion of the drug to provide the desired effect.
    [Show full text]
  • 2019 Gaurilcikaite Egle 14231
    This electronic thesis or dissertation has been downloaded from the King’s Research Portal at https://kclpure.kcl.ac.uk/portal/ Investigating mechanisms of odontogenic pain the role of odontoblasts, trigeminal ganglion neurons, and their interaction Gaurilcikaite, Egle Awarding institution: King's College London The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without proper acknowledgement. END USER LICENCE AGREEMENT Unless another licence is stated on the immediately following page this work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence. https://creativecommons.org/licenses/by-nc-nd/4.0/ You are free to copy, distribute and transmit the work Under the following conditions: Attribution: You must attribute the work in the manner specified by the author (but not in any way that suggests that they endorse you or your use of the work). Non Commercial: You may not use this work for commercial purposes. No Derivative Works - You may not alter, transform, or build upon this work. Any of these conditions can be waived if you receive permission from the author. Your fair dealings and other rights are in no way affected by the above. Take down policy If you believe that this document breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 09. Oct. 2021 Investigating mechanisms of odontogenic pain: the role of odontoblasts, trigeminal ganglion neurons, and their interaction Thesis submitted for the degree of Doctor of Philosophy Egle Gaurilcikaite Wolfson Centre for Age-Related Diseases Institute of Psychiatry, Psychology, and Neuroscience King’s College London 2014-2018 1 Abstract Despite the prevalence of pain originating from the teeth (dental, or odontogenic, pain) and its impact on patients’ lives, the cellular and molecular mechanisms of odontogenic pain are still not completely understood.
    [Show full text]
  • THE CONTRIBUTION of K+ ION CHANNELS and the Ca2+-PERMEABLE TRPM8 CHANNEL to BREAST CANCER CELL PROLIFERATION. by Jeremy W Roy Su
    THE CONTRIBUTION OF K+ ION CHANNELS AND THE Ca2+-PERMEABLE TRPM8 CHANNEL TO BREAST CANCER CELL PROLIFERATION. by Jeremy W Roy Submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Dalhousie University Halifax, Nova Scotia October 2010 © Copyright by Jeremy W Roy, 2010 DALHOUSIE UNIVERSITY DEPARTMENT OF PHYSIOLOGY AND BIOPHYSICS The undersigned hereby certify that they have read and recommend to the Faculty of Graduate Studies for acceptance a thesis entitled “THE CONTRIBUTION OF K+ ION CHANNELS AND THE Ca2+-PERMEABLE TRPM8 CHANNEL TO BREAST CANCER CELL PROLIFERATION” by Jeremy W Roy in partial fulfilment of the requirements for the degree of Doctor of Philosophy. Dated: October 26, 2010 Supervisor: _______________________________ Readers: _______________________________ _______________________________ _______________________________ ii DALHOUSIE UNIVERSITY DATE: October 26, 2010 AUTHOR: Jeremy W Roy TITLE: THE CONTRIBUTION OF K+ ION CHANNELS AND THE Ca2+- PERMEABLE TRPM8 CHANNEL TO BREAST CANCER CELL PROLIFERATION. DEPARTMENT OR SCHOOL: Department of Physiology and Biophysics DEGREE: PhD CONVOCATION: May YEAR: 2011 Permission is herewith granted to Dalhousie University to circulate and to have copied for non-commercial purposes, at its discretion, the above title upon the request of individuals or institutions. _______________________________ Signature of Author The author reserves other publication rights, and neither the thesis nor extensive extracts from it may be printed or otherwise reproduced without the author‟s written permission. The author attests that permission has been obtained for the use of any copyrighted material appearing in the thesis (other than the brief excerpts requiring only proper acknowledgement in scholarly writing), and that all such use is clearly acknowledged.
    [Show full text]
  • Cyclic Nucleotide-Gated Channels: Structural Basis of Ligand Efficacy and Allosteric Modulation
    Quarterly Reviews of Biophysics , (), pp. –. Printed in the United Kingdom # Cambridge University Press Cyclic nucleotide-gated channels: structural basis of ligand efficacy and allosteric modulation " # " JUN LI , WILLIAM N. ZAGOTTA HENRY A. LESTER * " Division of Biology, -, California Institute of Technology, Pasadena, CA , USA # Department of Physiology and Biophysics, Howard Hughes Medical Institute, University of Washington School of Medicine, Box , Seattle, WA -, USA . . . Single-subunit proteins . Multisubunit proteins . Linear state model . MWC model . : f . . L! # . Ca +}calmodulin . Transition metal ions . Protons . Thiol-modifying reagents . Phosphorylation, etc . . . . . Most working proteins, including metabolic enzymes, transcription regulators, and membrane receptors, transporters, and ion channels, share the property of allosteric coupling. The term ‘allosteric’ means that these proteins mediate indirect interactions between sites that are physically separated on the protein. In the example of ligand-gated ion channels, the binding of a suitable ligand elicits local conformational changes at the binding site, which are coupled to further * To whom correspondence and reprint requests should be addressed. Jun Li et al. conformational changes in regions distant from the binding site. The physical motions finally arrive at the site of biological activity: the ion-permeating pore. The conformational changes that lead from the ligand binding to the actual opening of the pore comprise
    [Show full text]