1
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Agyemang E, Gonneville AN, Tiruvadi-Krishnan S, Lamichhane R. Exploring GPCR conformational dynamics using single-molecule fluorescence. Methods 2024; 226:35-48. [PMID: 38604413 PMCID: PMC11098685 DOI: 10.1016/j.ymeth.2024.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/13/2024] Open
Abstract
G protein-coupled receptors (GPCRs) are membrane proteins that transmit specific external stimuli into cells by changing their conformation. This conformational change allows them to couple and activate G-proteins to initiate signal transduction. A critical challenge in studying and inferring these structural dynamics arises from the complexity of the cellular environment, including the presence of various endogenous factors. Due to the recent advances in cell-expression systems, membrane-protein purification techniques, and labeling approaches, it is now possible to study the structural dynamics of GPCRs at a single-molecule level both in vitro and in live cells. In this review, we discuss state-of-the-art techniques and strategies for expressing, purifying, and labeling GPCRs in the context of single-molecule research. We also highlight four recent studies that demonstrate the applications of single-molecule microscopy in revealing the dynamics of GPCRs. These techniques are also useful as complementary methods to verify the results obtained from other structural biology tools like cryo-electron microscopy and x-ray crystallography.
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Affiliation(s)
- Eugene Agyemang
- UT-ORNL Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996, USA
| | - Alyssa N Gonneville
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Sriram Tiruvadi-Krishnan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Rajan Lamichhane
- UT-ORNL Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996, USA; Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
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2
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Guillien M, Mouhand A, Sagar A, Fournet A, Allemand F, Pereira GAN, Thureau A, Bernadó P, Banères JL, Sibille N. Phosphorylation motif dictates GPCR C-terminal domain conformation and arrestin interaction. Structure 2023; 31:1394-1406.e7. [PMID: 37669668 DOI: 10.1016/j.str.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/07/2023] [Accepted: 08/09/2023] [Indexed: 09/07/2023]
Abstract
Arrestin-dependent G protein-coupled receptor (GPCR) signaling pathway is regulated by the phosphorylation state of GPCR's C-terminal domain, but the molecular bases of arrestin:receptor interaction are to be further illuminated. Here we investigated the impact of phosphorylation on the conformational features of the C-terminal region from three rhodopsin-like GPCRs, the vasopressin V2 receptor (V2R), the growth hormone secretagogue or ghrelin receptor type 1a (GHSR), and the β2-adernergic receptor (β2AR). Using phosphomimetic variants, we identified pre-formed secondary structure elements, or short linear motifs (SLiMs), that undergo specific conformational transitions upon phosphorylation. Of importance, such conformational transitions appear to favor arrestin-2 binding. Hence, our results suggest a model in which the phosphorylation-dependent structuration of the GPCR C-terminal regions would modulate arrestin binding and therefore signaling outcomes in arrestin-dependent pathways.
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Affiliation(s)
- Myriam Guillien
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Assia Mouhand
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Amin Sagar
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Aurélie Fournet
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Frédéric Allemand
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Glaécia A N Pereira
- Institut des Biomolécules Max Mousseron (IBMM), UMR-5247, University Montpellier, CNRS, ENSCM, Montpellier, France
| | - Aurélien Thureau
- HélioBio Section, Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, 91190 Gif-sur-Yvette, France
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron (IBMM), UMR-5247, University Montpellier, CNRS, ENSCM, Montpellier, France
| | - Nathalie Sibille
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France.
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3
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Heng J, Hu Y, Pérez-Hernández G, Inoue A, Zhao J, Ma X, Sun X, Kawakami K, Ikuta T, Ding J, Yang Y, Zhang L, Peng S, Niu X, Li H, Guixà-González R, Jin C, Hildebrand PW, Chen C, Kobilka BK. Function and dynamics of the intrinsically disordered carboxyl terminus of β2 adrenergic receptor. Nat Commun 2023; 14:2005. [PMID: 37037825 PMCID: PMC10085991 DOI: 10.1038/s41467-023-37233-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 03/07/2023] [Indexed: 04/12/2023] Open
Abstract
Advances in structural biology have provided important mechanistic insights into signaling by the transmembrane core of G-protein coupled receptors (GPCRs); however, much less is known about intrinsically disordered regions such as the carboxyl terminus (CT), which is highly flexible and not visible in GPCR structures. The β2 adrenergic receptor's (β2AR) 71 amino acid CT is a substrate for GPCR kinases and binds β-arrestins to regulate signaling. Here we show that the β2AR CT directly inhibits basal and agonist-stimulated signaling in cell lines lacking β-arrestins. Combining single-molecule fluorescence resonance energy transfer (FRET), NMR spectroscopy, and molecular dynamics simulations, we reveal that the negatively charged β2AR-CT serves as an autoinhibitory factor via interacting with the positively charged cytoplasmic surface of the receptor to limit access to G-proteins. The stability of this interaction is influenced by agonists and allosteric modulators, emphasizing that the CT plays important role in allosterically regulating GPCR activation.
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Affiliation(s)
- Jie Heng
- School of Medicine, Tsinghua University, Beijing, 100084, China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, 100084, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yunfei Hu
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Science, Wuhan, 430071, China
| | - Guillermo Pérez-Hernández
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Charitéplatz 1, 10117, Berlin, Germany
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Jiawei Zhao
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 100084, China
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiuyan Ma
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Xiaoou Sun
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Kouki Kawakami
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Tatsuya Ikuta
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Jienv Ding
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- College of Life Sciences, Peking University, Beijing, 100871, China
| | - Yujie Yang
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Lujia Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Sijia Peng
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaogang Niu
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Hongwei Li
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Ramon Guixà-González
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232, Villigen, PSI, Switzerland
| | - Changwen Jin
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Peter W Hildebrand
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Charitéplatz 1, 10117, Berlin, Germany
- Institute of Medical Physics and Biophysics, University Leipzig, 04107, Leipzig, Germany
- Berlin Institute of Health, 10178, Berlin, Germany
| | - Chunlai Chen
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, 100084, China.
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, 100084, China.
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 100084, China.
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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Péraldi-Roux S, Bayle M, M'Kadmi C, Damian M, Vaillé J, Fernandez G, Paula Cornejo M, Marie J, Banères JL, Ben Haj Salah K, Fehrentz JA, Cantel S, Perello M, Denoyelle S, Oiry C, Neasta J. Design and Characterization of a Triazole-Based Growth Hormone Secretagogue Receptor Modulator Inhibiting the Glucoregulatory and Feeding Actions of Ghrelin. Biochem Pharmacol 2022; 202:115114. [DOI: 10.1016/j.bcp.2022.115114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/26/2022] [Accepted: 05/26/2022] [Indexed: 11/02/2022]
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5
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Mustafá ER, Cordisco González S, Damian M, Cantel S, Denoyelle S, Wagner R, Schiöth HB, Fehrentz JA, Banères JL, Perelló M, Raingo J. LEAP2 Impairs the Capability of the Growth Hormone Secretagogue Receptor to Regulate the Dopamine 2 Receptor Signaling. Front Pharmacol 2021; 12:712437. [PMID: 34447311 PMCID: PMC8383165 DOI: 10.3389/fphar.2021.712437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/26/2021] [Indexed: 12/12/2022] Open
Abstract
The growth hormone secretagogue receptor (GHSR) signals in response to ghrelin, but also acts via ligand-independent mechanisms that include either constitutive activation or interaction with other G protein-coupled receptors, such as the dopamine 2 receptor (D2R). A key target of GHSR in neurons is voltage-gated calcium channels type 2.2 (CaV2.2). Recently, the liver-expressed antimicrobial peptide 2 (LEAP2) was recognized as a novel GHSR ligand, but the mechanism of action of LEAP2 on GHSR is not well understood. Here, we investigated the role of LEAP2 on the canonical and non-canonical modes of action of GHSR on CaV2.2 function. Using a heterologous expression system and patch-clamp recordings, we found that LEAP2 impairs the reduction of CaV2.2 currents induced by ghrelin-evoked and constitutive GHSR activities, acting as a GHSR antagonist and inverse agonist, respectively. We also found that LEAP2 prevents GHSR from modulating the effects of D2R signaling on CaV2.2 currents, and that the GHSR-binding N-terminal region LEAP2 underlies these effects. Using purified labeled receptors assembled into lipid nanodiscs and Forster Resonance Energy Transfer (FRET) assessments, we found that the N-terminal region of LEAP2 stabilizes an inactive conformation of GHSR that is dissociated from Gq protein and, consequently, reverses the effect of GHSR on D2R-dependent Gi activation. Thus, our results provide critical molecular insights into the mechanism mediating LEAP2 modulation of GHSR.
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Affiliation(s)
- Emilio R Mustafá
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata (UNLP)], La Plata, Argentina
| | - Santiago Cordisco González
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata (UNLP)], La Plata, Argentina
| | - Marjorie Damian
- Institut des Biomolécules Max Mousseron (IBMM), Université Montpellier, CNRS, Montpellier, France
| | - Sonia Cantel
- Institut des Biomolécules Max Mousseron (IBMM), Université Montpellier, CNRS, Montpellier, France
| | - Severine Denoyelle
- Institut des Biomolécules Max Mousseron (IBMM), Université Montpellier, CNRS, Montpellier, France
| | - Renaud Wagner
- Plateforme IMPReSs, CNRS UMR7242, Biotechnologie et Signalisation Cellulaire, École Supérieure de Biotechnologie de Strasbourg, Strasbourg, France
| | - Helgi B Schiöth
- Department of Neuroscience, Uppsala University, Uppsala, Sweden.,Institute for Translational Medicine and Biothechnology, I. M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Jean-Alain Fehrentz
- Institut des Biomolécules Max Mousseron (IBMM), Université Montpellier, CNRS, Montpellier, France
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron (IBMM), Université Montpellier, CNRS, Montpellier, France
| | - Mario Perelló
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata (UNLP)], La Plata, Argentina
| | - Jesica Raingo
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata (UNLP)], La Plata, Argentina
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6
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Dielectric Spectroscopy Based Detection of Specific and Nonspecific Cellular Mechanisms. SENSORS 2021; 21:s21093177. [PMID: 34063599 PMCID: PMC8124793 DOI: 10.3390/s21093177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/14/2022]
Abstract
Using radiofrequency dielectric spectroscopy, we have investigated the impact of the interaction between a G protein-coupled receptor (GPCR), the sterile2 α-factor receptor protein (Ste2), and its cognate agonist ligand, the α-factor pheromone, on the dielectric properties of the plasma membrane in living yeast cells (Saccharomyces cerevisiae). The dielectric properties of a cell suspension containing a saturating concentration of α-factor were measured over the frequency range 40Hz–110 MHz and compared to the behavior of a similarly prepared suspension of cells in the absence of α-factor. A spherical three-shell model was used to determine the electrical phase parameters for the yeast cells in both types of suspensions. The relative permittivity of the plasma membrane showed a significant increase after exposure to α-factor (by 0.06 ± 0.05). The equivalent experiment performed on yeast cells lacking the ability to express Ste2 showed no change in plasma membrane permittivity. Interestingly, a large change also occurred to the electrical properties of the cellular interior after the addition of α-factor to the cell suspending medium, whether or not the cells were expressing Ste2. We present a number of different complementary experiments performed on the yeast to support these dielectric data and interpret the results in terms of specific cellular reactions to the presence of α-factor.
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7
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Mersch K, Ozturk TN, Park K, Lim HH, Robertson JL. Altering CLC stoichiometry by reducing non-polar side-chains at the dimerization interface. J Mol Biol 2021; 433:166886. [PMID: 33617898 DOI: 10.1016/j.jmb.2021.166886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/03/2021] [Accepted: 02/16/2021] [Indexed: 10/22/2022]
Abstract
CLC-ec1 is a Cl-/H+ antiporter that forms stable homodimers in lipid bilayers, with a free energy of -10.9 kcal/mol in 2:1 POPE/POPG lipid bilayers. The dimerization interface is formed by four transmembrane helices: H, I, P and Q, that are lined by non-polar side-chains that come in close contact, yet it is unclear as to whether their interactions drive dimerization. To investigate whether non-polar side-chains are required for dimer assembly, we designed a series of constructs where side-chain packing in the dimer state is significantly reduced by making 4-5 alanine substitutions along each helix (H-ala, I-ala, P-ala, Q-ala). All constructs are functional and three purify as stable dimers in detergent micelles despite the removal of significant side-chain interactions. On the other hand, H-ala shows the unique behavior of purifying as a mixture of monomers and dimers, followed by a rapid and complete conversion to monomers. In lipid bilayers, all four constructs are monomeric as examined by single-molecule photobleaching analysis. Further study of the H-helix shows that the single mutation L194A is sufficient to yield monomeric CLC-ec1 in detergent micelles and lipid bilayers. X-ray crystal structures of L194A reveal the protein re-assembles to form dimers, with a structure that is identical to wild-type. Altogether, these results demonstrate that non-polar membrane embedded side-chains play an important role in defining dimer stability, but the stoichiometry is highly contextual to the solvent environment. Furthermore, we discovered that L194 is a molecular hot-spot for defining dimerization of CLC-ec1.
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Affiliation(s)
- Kacey Mersch
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - Tugba N Ozturk
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Kunwoong Park
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, 41068 Daegu, Republic of Korea
| | - Hyun-Ho Lim
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, 41068 Daegu, Republic of Korea; Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, 42988 Daegu, Republic of Korea
| | - Janice L Robertson
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine in St. Louis, St. Louis, MO, USA.
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Calebiro D, Koszegi Z, Lanoiselée Y, Miljus T, O'Brien S. G protein-coupled receptor-G protein interactions: a single-molecule perspective. Physiol Rev 2020; 101:857-906. [PMID: 33331229 DOI: 10.1152/physrev.00021.2020] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) regulate many cellular and physiological processes, responding to a diverse range of extracellular stimuli including hormones, neurotransmitters, odorants, and light. Decades of biochemical and pharmacological studies have provided fundamental insights into the mechanisms of GPCR signaling. Thanks to recent advances in structural biology, we now possess an atomistic understanding of receptor activation and G protein coupling. However, how GPCRs and G proteins interact in living cells to confer signaling efficiency and specificity remains insufficiently understood. The development of advanced optical methods, including single-molecule microscopy, has provided the means to study receptors and G proteins in living cells with unprecedented spatio-temporal resolution. The results of these studies reveal an unexpected level of complexity, whereby GPCRs undergo transient interactions among themselves as well as with G proteins and structural elements of the plasma membrane to form short-lived signaling nanodomains that likely confer both rapidity and specificity to GPCR signaling. These findings may provide new strategies to pharmaceutically modulate GPCR function, which might eventually pave the way to innovative drugs for common diseases such as diabetes or heart failure.
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Affiliation(s)
- Davide Calebiro
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Zsombor Koszegi
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Yann Lanoiselée
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Tamara Miljus
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Shannon O'Brien
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
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9
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Capturing Peptide-GPCR Interactions and Their Dynamics. Molecules 2020; 25:molecules25204724. [PMID: 33076289 PMCID: PMC7587574 DOI: 10.3390/molecules25204724] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 12/16/2022] Open
Abstract
Many biological functions of peptides are mediated through G protein-coupled receptors (GPCRs). Upon ligand binding, GPCRs undergo conformational changes that facilitate the binding and activation of multiple effectors. GPCRs regulate nearly all physiological processes and are a favorite pharmacological target. In particular, drugs are sought after that elicit the recruitment of selected effectors only (biased ligands). Understanding how ligands bind to GPCRs and which conformational changes they induce is a fundamental step toward the development of more efficient and specific drugs. Moreover, it is emerging that the dynamic of the ligand–receptor interaction contributes to the specificity of both ligand recognition and effector recruitment, an aspect that is missing in structural snapshots from crystallography. We describe here biochemical and biophysical techniques to address ligand–receptor interactions in their structural and dynamic aspects, which include mutagenesis, crosslinking, spectroscopic techniques, and mass-spectrometry profiling. With a main focus on peptide receptors, we present methods to unveil the ligand–receptor contact interface and methods that address conformational changes both in the ligand and the GPCR. The presented studies highlight a wide structural heterogeneity among peptide receptors, reveal distinct structural changes occurring during ligand binding and a surprisingly high dynamics of the ligand–GPCR complexes.
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10
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Haj Salah KB, Maingot M, Blayo AL, M'Kadmi C, Damian M, Mary S, Cantel S, Neasta J, Oiry C, Péraldi-Roux S, Fernandez G, Romero GG, Perello M, Marie J, Banères JL, Fehrentz JA, Denoyelle S. Development of Nonpeptidic Inverse Agonists of the Ghrelin Receptor (GHSR) Based on the 1,2,4-Triazole Scaffold. J Med Chem 2020; 63:10796-10815. [PMID: 32882134 DOI: 10.1021/acs.jmedchem.9b02122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GHSR controls, among others, growth hormone and insulin secretion, adiposity, feeding, and glucose metabolism. Therefore, an inverse agonist ligand capable of selectively targeting GHSR and reducing its high constitutive activity appears to be a good candidate for the treatment of obesity-related metabolic diseases. In this context, we present a study that led to the development of several highly potent and selective inverse agonists of GHSR based on the 1,2,4-triazole scaffold. We demonstrate that, depending on the nature of the substituents on positions 3, 4, and 5, this scaffold leads to ligands that exert an intrinsic inverse agonist activity on GHSR-catalyzed G protein activation through the stabilization of a specific inactive receptor conformation. Thanks to an in vivo evaluation, we also show that one of the most promising ligands not only exerts an effect on insulin secretion in rat pancreatic islets but also affects the orexigenic effects of ghrelin in mice.
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Affiliation(s)
| | - Mathieu Maingot
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Anne-Laure Blayo
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Céline M'Kadmi
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Marjorie Damian
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Sophie Mary
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Sonia Cantel
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Jérémie Neasta
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Catherine Oiry
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Sylvie Péraldi-Roux
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Gimena Fernandez
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell, La Plata, Buenos Aires 1900, Argentina
| | - Guadalupe García Romero
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell, La Plata, Buenos Aires 1900, Argentina
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell, La Plata, Buenos Aires 1900, Argentina
| | - Jacky Marie
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Jean-Louis Banères
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Jean-Alain Fehrentz
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
| | - Séverine Denoyelle
- IBMM, Univ Montpellier, CNRS, ENSCM, Faculty of Pharmacy, 34000 Montpellier, France
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Weihs F, Wang J, Pfleger KDG, Dacres H. Experimental determination of the bioluminescence resonance energy transfer (BRET) Förster distances of NanoBRET and red-shifted BRET pairs. Anal Chim Acta X 2020; 6:100059. [PMID: 33392495 PMCID: PMC7772631 DOI: 10.1016/j.acax.2020.100059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/08/2020] [Accepted: 08/30/2020] [Indexed: 01/07/2023] Open
Abstract
Bioluminescence Resonance Energy Transfer (BRET) is widely applied to study protein-protein interactions, as well as increasingly to monitor both ligand binding and molecular rearrangements. The Förster distance (R0) describes the physical distance between the two chromophores at which 50% of the maximal energy transfer occurs and it depends on the choice of RET components. R0 can be experimentally determined using flexible peptide linkers of known lengths to separate the two chromophores. Knowledge of the R0 helps to inform on the choice of BRET system. For example, we have previously shown that BRET2 exhibits the largest R0 to date for any genetically encoded RET pair, which may be advantageous for investigating large macromolecular complexes if its issues of low and fast-decaying bioluminescence signal can be accommodated. In this study we have determined R0 for a range of bright and red-shifted BRET pairs, including NanoBRET with tetramethylrhodamine (TMR), non-chloro TOM (NCT), mCherry or Venus as acceptor, and BRET6, a red-shifted BRET2-like system. This study revealed R0 values of 6.15 nm and 6.94 nm for NanoBRET using TMR or NCT as acceptor ligands, respectively. R0 was 5.43 nm for NanoLuc-mCherry, 5.59 nm for NanoLuc-Venus and 5.47 nm for BRET6. This extends the palette of available BRET Förster distances, to give researchers a better-informed choice when considering BRET systems and points towards NanoBRET with NCT as a good alternative to BRET2 as an analysis tool for large macromolecular complexes. Experimental determination of Förster distances (R0) for commonly applied BRET pairs. Determination of R0 for NanoBRET with Venus, mCherry and HaloTag (TMR, NCT). Determination of R0 for BRET6. NanoLuc-HaloTag (NCT) exhibits the second largest R0 of any genetically encoded system.
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Affiliation(s)
- Felix Weihs
- CSIRO Health & Biosecurity, Parkville, 343 Royal Parade, Melbourne, VIC, 3030, Australia
| | - Jian Wang
- CSIRO Health & Biosecurity, Canberra, ACT, 2601, Australia
| | - Kevin D G Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, WA, 6009, Australia.,Australian Research Council Centre for Personalised Therapeutics Technologies, Australia.,Dimerix Limited, Nedlands, WA, Australia
| | - Helen Dacres
- CSIRO Health & Biosecurity, Food Innovation Centre, 671 Sneydes Road, Werribee, VIC, 3030, Australia
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12
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A Systematic Review of Inverse Agonism at Adrenoceptor Subtypes. Cells 2020; 9:cells9091923. [PMID: 32825009 PMCID: PMC7564766 DOI: 10.3390/cells9091923] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022] Open
Abstract
As many, if not most, ligands at G protein-coupled receptor antagonists are inverse agonists, we systematically reviewed inverse agonism at the nine adrenoceptor subtypes. Except for β3-adrenoceptors, inverse agonism has been reported for each of the adrenoceptor subtypes, most often for β2-adrenoceptors, including endogenously expressed receptors in human tissues. As with other receptors, the detection and degree of inverse agonism depend on the cells and tissues under investigation, i.e., they are greatest when the model has a high intrinsic tone/constitutive activity for the response being studied. Accordingly, they may differ between parts of a tissue, for instance, atria vs. ventricles of the heart, and within a cell type, between cellular responses. The basal tone of endogenously expressed receptors is often low, leading to less consistent detection and a lesser extent of observed inverse agonism. Extent inverse agonism depends on specific molecular properties of a compound, but inverse agonism appears to be more common in certain chemical classes. While inverse agonism is a fascinating facet in attempts to mechanistically understand observed drug effects, we are skeptical whether an a priori definition of the extent of inverse agonism in the target product profile of a developmental candidate is a meaningful option in drug discovery and development.
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Guillien M, le Maire A, Mouhand A, Bernadó P, Bourguet W, Banères JL, Sibille N. IDPs and their complexes in GPCR and nuclear receptor signaling. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 174:105-155. [DOI: 10.1016/bs.pmbts.2020.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Crystallization and Biophysical Approaches for Studying the Interactions Between the Vps4-MIT Domain and ESCRT-III Proteins. Methods Mol Biol 2019. [PMID: 31250302 DOI: 10.1007/978-1-4939-9492-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The AAA ATPase Vps4 disassembles the ESCRT complex from the endosomal membrane. Vps4 contains an N-terminal MIT (microtubule interacting and transport) domain and a C-terminal catalytic domain. The MIT domain binds to MIMs (MIT-interacting motifs), which exist at the C-terminus of ESCRT-III proteins, with a dissociation constant in the micromolar range. Five MIMs have been identified by structural and biophysical methods to date, and the recognition motifs have been refined. Among biophysical approaches used to analyze protein interactions, surface plasmon resonance (SPR) analysis is often suitable for weak interactions, and fluorescence-binding assay has an advantage in terms of sensitivity. We have introduced protein modification tags into the N-terminus of proteins with bacterial expression vectors for biotinylation and FlAsH (fluorescein arsenical hairpin binder) fluorescent labeling. Here, we describe how to purify the MIT domain of Vps4 and the MIMs of ESCRT-III proteins and how to conduct crystallography, SPR, and fluorescence-binding assays.
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Angiotensin Analogs with Divergent Bias Stabilize Distinct Receptor Conformations. Cell 2019; 176:468-478.e11. [PMID: 30639099 DOI: 10.1016/j.cell.2018.12.005] [Citation(s) in RCA: 159] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/13/2018] [Accepted: 12/04/2018] [Indexed: 01/14/2023]
Abstract
"Biased" G protein-coupled receptor (GPCR) agonists preferentially activate pathways mediated by G proteins or β-arrestins. Here, we use double electron-electron resonance spectroscopy to probe the changes that ligands induce in the conformational distribution of the angiotensin II type I receptor. Monitoring distances between 10 pairs of nitroxide labels distributed across the intracellular regions enabled mapping of four underlying sets of conformations. Ligands from different functional classes have distinct, characteristic effects on the conformational heterogeneity of the receptor. Compared to angiotensin II, the endogenous agonist, agonists with enhanced Gq coupling more strongly stabilize an "open" conformation with an accessible transducer-binding site. β-arrestin-biased agonists deficient in Gq coupling do not stabilize this open conformation but instead favor two more occluded conformations. These data suggest a structural mechanism for biased ligand action at the angiotensin receptor that can be exploited to rationally design GPCR-targeting drugs with greater specificity of action.
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M’Kadmi C, Cabral A, Barrile F, Giribaldi J, Cantel S, Damian M, Mary S, Denoyelle S, Dutertre S, Péraldi-Roux S, Neasta J, Oiry C, Banères JL, Marie J, Perello M, Fehrentz JA. N-Terminal Liver-Expressed Antimicrobial Peptide 2 (LEAP2) Region Exhibits Inverse Agonist Activity toward the Ghrelin Receptor. J Med Chem 2018; 62:965-973. [DOI: 10.1021/acs.jmedchem.8b01644] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Céline M’Kadmi
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Agustina Cabral
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell, La Plata, 1900 Buenos Aires, Argentina
| | - Franco Barrile
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell, La Plata, 1900 Buenos Aires, Argentina
| | - Julien Giribaldi
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Sonia Cantel
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Marjorie Damian
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Sophie Mary
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Séverine Denoyelle
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Sébastien Dutertre
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Sylvie Péraldi-Roux
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Jérémie Neasta
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Catherine Oiry
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Jean-Louis Banères
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Jacky Marie
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell, La Plata, 1900 Buenos Aires, Argentina
| | - Jean-Alain Fehrentz
- Faculté de Pharmacie, Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, 15 avenue Charles Flahaut, BP 14491, 34093 Montpellier cedex
5, France
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Conformational changes in Arp2/3 complex induced by ATP, WASp-VCA, and actin filaments. Proc Natl Acad Sci U S A 2018; 115:E8642-E8651. [PMID: 30150414 DOI: 10.1073/pnas.1717594115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We used fluorescence spectroscopy and EM to determine how binding of ATP, nucleation-promoting factors, actin monomers, and actin filaments changes the conformation of Arp2/3 complex during the process that nucleates an actin filament branch. We mutated subunits of Schizosaccharomyces pombe Arp2/3 complex for labeling with fluorescent dyes at either the C termini of Arp2 and Arp3 or ArpC1 and ArpC3. We measured Förster resonance energy transfer (FRET) efficiency (ETeff) between the dyes in the presence of the various ligands. We also computed class averages from electron micrographs of negatively stained specimens. ATP binding made small conformational changes of the nucleotide-binding cleft of the Arp2 subunit. WASp-VCA, WASp-CA, and WASp-actin-VCA changed the ETeff between the dyes on the Arp2 and Arp3 subunits much more than between dyes on ArpC1 and ArpC3. Ensemble FRET detected an additional structural change that brought ArpC1 and ArpC3 closer together when Arp2/3 complex bound actin filaments. VCA binding to Arp2/3 complex causes a conformational change that favors binding to the side of an actin filament, which allows further changes required to nucleate a daughter filament.
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18
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A universal bioluminescence resonance energy transfer sensor design enables high-sensitivity screening of GPCR activation dynamics. Commun Biol 2018; 1:105. [PMID: 30271985 PMCID: PMC6123785 DOI: 10.1038/s42003-018-0072-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 05/11/2018] [Indexed: 11/10/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) represent one of the most important classes of drug targets. The discovery of new GCPR therapeutics would greatly benefit from the development of a generalizable high-throughput assay to directly monitor their activation or de-activation. Here we screened a variety of labels inserted into the third intracellular loop and the C-terminus of the α2A-adrenergic receptor and used fluorescence (FRET) and bioluminescence resonance energy transfer (BRET) to monitor ligand-binding and activation dynamics. We then developed a universal intramolecular BRET receptor sensor design to quantify efficacy and potency of GPCR ligands in intact cells and real time. We demonstrate the transferability of the sensor design by cloning β2-adrenergic and PTH1-receptor BRET sensors and monitored their efficacy and potency. For all biosensors, the Z factors were well above 0.5 showing the suitability of such design for microtiter plate assays. This technology will aid the identification of novel types of GPCR ligands. Hannes Schihada et al. report the design of 11 BRET-based biosensors that allow for quantification of GPCR ligand-binding dynamics in a micro-titer format. The biosensors achieve higher dynamic range and sensitivity than FRET-based biosensors and their design can be extended to the study of other receptor types.
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Ulloa-Aguirre A, Reiter E, Crépieux P. FSH Receptor Signaling: Complexity of Interactions and Signal Diversity. Endocrinology 2018; 159:3020-3035. [PMID: 29982321 DOI: 10.1210/en.2018-00452] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/27/2018] [Indexed: 12/20/2022]
Abstract
FSH is synthesized in the pituitary by gonadotrope cells. By binding to and interacting with its cognate receptor [FSH receptor (FSHR)] in the gonads, this gonadotropin plays a key role in the control of gonadal function and reproduction. Upon activation, the FSHR undergoes conformational changes leading to transduction of intracellular signals, including dissociation of G protein complexes into components and activation of several associated interacting partners, which concertedly regulate downstream effectors. The canonical Gs/cAMP/protein kinase A pathway, considered for a long time as the sole effector of FSHR-mediated signaling, is now viewed as one of several mechanisms employed by this receptor to transduce intracellular signals in response to the FSH stimulus. This complex network of signaling pathways allows for a fine-tuning regulation of the gonadotropic stimulus, where activation/inhibition of its multiple components vary depending on the cell context, cell developmental stage, and concentration of associated receptors and corresponding ligands. Activation of these multiple signaling modules eventually converge to the hormone-integrated biological response, including survival, proliferation and differentiation of target cells, synthesis and secretion of paracrine/autocrine regulators, and, at the molecular level, functional selectivity and differential gene expression. In this mini-review, we discuss the complexity of FSHR-mediated intracellular signals activated in response to ligand stimulation. A better understanding of the signaling pathways involved in FSH action might potentially influence the development of new therapeutic strategies for reproductive disorders.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Eric Reiter
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
| | - Pascale Crépieux
- Biology and Bioinformatics of Signaling Systems Group, Unité Mixtes de Recherche 85, Unité Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, Nouzilly, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7247, Nouzilly, France
- Université François Rabelais, Nouzilly, France
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20
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Maity BK, Vishvakarma V, Surendran D, Rawat A, Das A, Pramanik S, Arfin N, Maiti S. Spontaneous Fluctuations Can Guide Drug Design Strategies for Structurally Disordered Proteins. Biochemistry 2018; 57:4206-4213. [PMID: 29928798 DOI: 10.1021/acs.biochem.8b00504] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Structure-based "rational" drug design strategies fail for diseases associated with intrinsically disordered proteins (IDPs). However, structural disorder allows large-amplitude spontaneous intramolecular dynamics in a protein. We demonstrate a method that exploits this dynamics to provide quantitative information about the degree of interaction of an IDP with other molecules. A candidate ligand molecule may not bind strongly, but even momentary interactions can be expected to perturb the fluctuations. We measure the amplitude and frequency of the equilibrium fluctuations of fluorescently labeled small oligomers of hIAPP (an IDP associated with type II diabetes) in a physiological solution, using nanosecond fluorescence cross-correlation spectroscopy. We show that the interterminal distance fluctuates at a characteristic time scale of 134 ± 10 ns, and 6.4 ± 0.2% of the population is in the "closed" (quenched) state at equilibrium. These fluctuations are affected in a dose-dependent manner by a series of small molecules known to reduce the toxicity of various amyloid peptides. The degree of interaction increases in the following order: resveratrol < epicatechin ∼ quercetin < Congo red < epigallocatechin 3-gallate. Such ordering can provide a direction for exploring the chemical space for finding stronger-binding ligands. We test the biological relevance of these measurements by measuring the effect of these molecules on the affinity of hIAPP for lipid vesicles and cell membranes. We find that the ability of a molecule to modulate intramolecular fluctuations correlates well with its ability to lower membrane affinity. We conclude that structural disorder may provide new avenues for rational drug design for IDPs.
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Affiliation(s)
- Barun Kumar Maity
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road , Colaba, Mumbai 400005 , India
| | - Vicky Vishvakarma
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road , Colaba, Mumbai 400005 , India
| | - Dayana Surendran
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road , Colaba, Mumbai 400005 , India
| | - Anoop Rawat
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road , Colaba, Mumbai 400005 , India
| | - Anirban Das
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road , Colaba, Mumbai 400005 , India
| | - Shreya Pramanik
- UM-DAE Centre for Excellence in Basic Sciences , University of Mumbai , Kalina, Mumbai 400098 , India
| | - Najmul Arfin
- Center for Interdisciplinary Research in Basic Sciences , Jamia Milia Islamia , New Delhi 110025 , India
| | - Sudipta Maiti
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road , Colaba, Mumbai 400005 , India
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Patel MJ, Yilmaz G, Bhatia L, Biswas-Fiss EE, Biswas SB. Site-specific fluorescence double-labeling of proteins and analysis of structural changes in solution by Fluorescence Resonance Energy Transfer (FRET). MethodsX 2018; 5:419-430. [PMID: 30013941 PMCID: PMC6043909 DOI: 10.1016/j.mex.2018.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 03/26/2018] [Indexed: 11/29/2022] Open
Abstract
Insertion of a Cys4 sequence and single Cys motif allowedsite-specific labeling with FlAsH and Alexa568 of a protein. FRET is a well-known technique useful for analysis of structural changes of proteins labeled with donor and accepter fluorophores. Inter-fluorophore distances and proximity ratios of the peakintensities are used to understand structural changes.
Fluorescence Resonance Energy Transfer (FRET) is a well-known methodology for detection and quantitation of structural changes of proteins in solution. FRET requires site-specific protein labeling with two fluorophores, one of which functions as an energy donor and the other one as an energy acceptor. However, the site-specific labeling of protein is often complex and difficult, particularly when inserting two fluorophores in specific sites. We have examined several protein labeling approaches with a varying degree of success. Described here is a dual labeling strategy that worked reproducibly in a number of protein targets and we believe will be applicable to a variety of proteins, which have few or no native cysteine (Cys) residues. We have successfully double-labeled DnaA protein of Bacillus anthracis, which lacks intrinsic Cys residues. A cysteine residue was inserted at the N-terminus by in vitro mutagenesis and a Cys-Cys-Phe-Gly-Cys-Cys (CCPGCC) sequence at the C-terminus by PCR. This protein was labeled site-specifically with a fluorescein derivative, FlAsH, at the CCPGCC sequence followed by Alexa568 maleimide at the N-terminus Cys residue. Structural changes of the protein with nucleotide, DNA and an inhibitor protein binding were determined by FRET analysis of the double-labeled protein. This comprehensive novel methodology for site-specific protein labeling with different fluorophores is applicable for understanding different in vitro proteomic structural studies. Here, we describe a verified technique used for FRET spectral analysis and quantitative evaluation of structural changes using fluorophore labeled DnaA protein constructs as an example.
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Affiliation(s)
- Meera J Patel
- Program in Biotechnology, Department of Medical Laboratory Sciences, College of Health Sciences, University of Delaware, Newark, DE 19716, United States
| | - Gulden Yilmaz
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, United States
| | - Lavesh Bhatia
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, United States
| | - Esther E Biswas-Fiss
- Program in Biotechnology, Department of Medical Laboratory Sciences, College of Health Sciences, University of Delaware, Newark, DE 19716, United States
| | - Subhasis B Biswas
- Program in Biotechnology, Department of Medical Laboratory Sciences, College of Health Sciences, University of Delaware, Newark, DE 19716, United States
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Follicle-Stimulating Hormone Receptor: Advances and Remaining Challenges. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:1-58. [DOI: 10.1016/bs.ircmb.2018.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Wang J, Liu Y, Zhang J, Han Z, Wang W, Liu Y, Wei D, Huang W. Cell-free expression, purification, and characterization of the functional β2-adrenergic receptor for multianalyte detection of β-agonists. BIOCHEMISTRY (MOSCOW) 2017; 82:1346-1353. [DOI: 10.1134/s0006297917110128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Patel MJ, Bhatia L, Yilmaz G, Biswas-Fiss EE, Biswas SB. Multiple conformational states of DnaA protein regulate its interaction with DnaA boxes in the initiation of DNA replication. Biochim Biophys Acta Gen Subj 2017. [PMID: 28630006 DOI: 10.1016/j.bbagen.2017.06.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
DnaA protein is the initiator of genomic DNA replication in prokaryotes. It binds to specific DNA sequences in the origin of DNA replication and unwinds small AT-rich sequences downstream for the assembly of the replisome. The mechanism of activation of DnaA that enables it to bind and organize the origin DNA and leads to replication initiation remains unclear. In this study, we have developed double-labeled fluorescent DnaA probes to analyze conformational states of DnaA protein upon binding DNA, nucleotide, and Soj sporulation protein using Fluorescence Resonance Energy Transfer (FRET). Our studies demonstrate that DnaA protein undergoes large conformational changes upon binding to substrates and there are multiple distinct conformational states that enable it to initiate DNA replication. DnaA protein adopted a relaxed conformation by expanding ~15Å upon binding ATP and DNA to form the ATP·DnaA·DNA complex. Hydrolysis of bound ATP to ADP led to a contraction of DnaA within the complex. The relaxed conformation of DnaA is likely required for the formation of the multi-protein ATP·DnaA·DNA complex. In the initiation of sporulation, Soj binding to DnaA prevented relaxation of its conformation. Soj·ADP appeared to block the activation of DnaA, suggesting a mechanism for Soj·ADP in switching initiation of DNA replication to sporulation. Our studies demonstrate that multiple conformational states of DnaA protein regulate its binding to DNA in the initiation of DNA replication.
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Affiliation(s)
- Meera J Patel
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, United States; Program in Biotechnology, Department of Medical Laboratory Sciences, College of Health Sciences, University of Delaware, Newark, DE 19716, United States
| | - Lavesh Bhatia
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, United States
| | - Gulden Yilmaz
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, United States
| | - Esther E Biswas-Fiss
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, United States; Program in Biotechnology, Department of Medical Laboratory Sciences, College of Health Sciences, University of Delaware, Newark, DE 19716, United States
| | - Subhasis B Biswas
- Department of Molecular Biology, Rowan University, Stratford, NJ 08084, United States.
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Kufareva I, Gustavsson M, Zheng Y, Stephens BS, Handel TM. What Do Structures Tell Us About Chemokine Receptor Function and Antagonism? Annu Rev Biophys 2017; 46:175-198. [PMID: 28532213 PMCID: PMC5764094 DOI: 10.1146/annurev-biophys-051013-022942] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chemokines and their cell surface G protein-coupled receptors are critical for cell migration, not only in many fundamental biological processes but also in inflammatory diseases and cancer. Recent X-ray structures of two chemokines complexed with full-length receptors provided unprecedented insight into the atomic details of chemokine recognition and receptor activation, and computational modeling informed by new experiments leverages these insights to gain understanding of many more receptor:chemokine pairs. In parallel, chemokine receptor structures with small molecules reveal the complicated and diverse structural foundations of small molecule antagonism and allostery, highlight the inherent physicochemical challenges of receptor:chemokine interfaces, and suggest novel epitopes that can be exploited to overcome these challenges. The structures and models promote unique understanding of chemokine receptor biology, including the interpretation of two decades of experimental studies, and will undoubtedly assist future drug discovery endeavors.
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Affiliation(s)
- Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093; ,
| | - Martin Gustavsson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093; ,
| | - Yi Zheng
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093; ,
| | - Bryan S Stephens
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093; ,
| | - Tracy M Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093; ,
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26
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Scheggi S, Ferrari A, Pelliccia T, Devoto P, De Montis MG, Gambarana C. Fasting biases μ-opioid receptors toward β-arrestin2-dependent signaling in the accumbens shell. Neuroscience 2017; 352:19-29. [PMID: 28391016 DOI: 10.1016/j.neuroscience.2017.03.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/03/2017] [Accepted: 03/28/2017] [Indexed: 10/19/2022]
Abstract
The μ-opioid receptor (MOR) and dopamine D1 receptor are co-expressed in the medium spiny neurons of striatal areas and the signaling pathways activated by these two receptors are in functional competition. However, in certain conditions an integrated response mediated by the dopamine D1 receptor transduction system is observed. In mice, morphine administration induces hypermotility and this response has been described in terms of a β-arrestin2-dependent mechanism that favors prevalent dopamine D1 receptor activation. In rats, acute morphine administration induces hypermotility only when the animals are food-deprived (FD). We aimed to further investigate the functional interaction between the MOR and dopamine D1 receptors in striatal areas and we studied the effects of acute pharmacological MOR stimulation on motility and nucleus accumbens shell (NAcS) dopamine D1 receptor signaling in control rats and rats with reduced β-arrestin2 expression in the NAcS, either non food-deprived (NFD) or FD. Motility and dopamine D1 receptor signaling increased only in FD rats in a β-arrestin2-dependent way. Moreover, FD rats showed a β-arrestin2-dependent increase in the levels of MOR-dopamine D1 receptor heteromeric complexes in the NAcS. Sucrose consumption is accompanied by release of endogenous opioids and dopamine in the NAcS. We then examined MOR-dopamine D1 receptor interactions after sucrose consumption. Sucrose increased NAcS dopamine D1 receptor signaling in NFD and FD rats, and a reduction in β-arrestin2 expression prevented this effect selectively in FD rats. These results show the β-arrestin2-dependent prevalence of dopamine D1 receptor signaling in response to acute morphine or sucrose consumption elicited by food deprivation in rats.
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Affiliation(s)
- Simona Scheggi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Alberto Ferrari
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Teresa Pelliccia
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Paola Devoto
- Department of Biomedical Sciences, University of Cagliari, Italy
| | | | - Carla Gambarana
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.
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27
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Błasiak E, Łukasiewicz S, Szafran-Pilch K, Dziedzicka-Wasylewska M. Genetic variants of dopamine D2 receptor impact heterodimerization with dopamine D1 receptor. Pharmacol Rep 2016; 69:235-241. [PMID: 28119185 DOI: 10.1016/j.pharep.2016.10.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 01/14/2023]
Abstract
BACKGROUND The human dopamine D2 receptor gene has three polymorphic variants that alter its amino acid sequence: alanine substitution by valine in position 96 (V96A), proline substitution by serine in position 310 (P310S) and serine substitution by cysteine in position 311 (S311C). Their functional role has never been the object of extensive studies, even though there is some evidence that their occurrence correlates with schizophrenia. METHODS The HEK293 cell line was transfected with dopamine D1 and D2 receptors (or genetic variants of the D2 receptor), coupled to fluorescent proteins which allowed us to measure the extent of dimerization of these receptors, using a highly advanced biophysical approach (FLIM-FRET). Additionally, Fluoro-4 AM was used to examine changes in the level of calcium release after ligand stimulation of cells expressing different combinations of dopamine receptors. RESULTS Using FLIM-FRET experiments we have shown that in HEK 293 expressing dopamine receptors, polymorphic mutations in the D2 receptor play a role in dimmer formation with the dopamine D1 receptor. The association level of dopamine receptors is affected by ligand administration, with variable effects depending on polymorphic variant of the D2 dopamine receptor. We have found that the level of heteromer formation is reflected by calcium ion release after ligand stimulation and have observed variations of this effect dependent on the polymorphic variant and the ligand. CONCLUSION The data presented in this paper support the hypothesis on the role of calcium signaling regulated by the D1-D2 heteromer which may be of relevance for schizophrenia etiology.
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Affiliation(s)
- Ewa Błasiak
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
| | - Sylwia Łukasiewicz
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
| | | | - Marta Dziedzicka-Wasylewska
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland; Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
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28
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Han CC, Ma Y, Li Y, Wang Y, Wei W. Regulatory effects of GRK2 on GPCRs and non-GPCRs and possible use as a drug target (Review). Int J Mol Med 2016; 38:987-94. [DOI: 10.3892/ijmm.2016.2720] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/22/2016] [Indexed: 11/06/2022] Open
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29
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Use of Fluorescence Indicators in Receptor Ligands. Methods Mol Biol 2016; 1335:115-30. [PMID: 26260598 DOI: 10.1007/978-1-4939-2914-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fluorescence techniques can provide insights into the environment of fluorescence indicators incorporated within a ligand as it is bound to its receptor. Fluorescence indicators of different sizes and chemical characteristics can provide insights into the nature of the binding environment, the surrounding structures, and even into conformational changes associated with receptor activation. Methods for determining fluorescence spectral analysis, fluorescence quenching, fluorescence anisotropy, fluorescence lifetimes, and red edge excitation shifts of the ligand probes are described. The applications of these techniques to the CCK1 receptor occupied by alexa(488)-CCK and aladan-CCK, as examples of probes developed (1) by derivatization of an existing peptide and (2) by incorporation during peptide synthesis, are utilized as examples. These methods represent powerful tools to expand our understanding of the structure and molecular basis of ligand activation of G protein-coupled receptors.
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30
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Keenan CR, Lew MJ, Stewart AG. Biased signalling from the glucocorticoid receptor: Renewed opportunity for tailoring glucocorticoid activity. Biochem Pharmacol 2016; 112:6-12. [PMID: 26898958 DOI: 10.1016/j.bcp.2016.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/16/2016] [Indexed: 12/13/2022]
Abstract
Recent landmark studies applying analytical pharmacology approaches to the glucocorticoid receptor (GR) have demonstrated that different ligands can cause differential activation of distinct GR-regulated genes. Drawing on concepts of signalling bias from the field of G protein-coupled receptor (GPCR) biology, we speculate that ligand-dependent differences in GR signalling can be considered analogous to GPCR biased signalling, and thus can be quantitatively analysed in a similar way. This type of approach opens up the possibility of using rational structure-based drug optimisation strategies to improve the therapeutic selectivity of glucocorticoid drugs to maximise their efficacy and minimise adverse effects.
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Affiliation(s)
- Christine R Keenan
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michael J Lew
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alastair G Stewart
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Victoria 3010, Australia.
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31
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Shim JY, Khurana L, Kendall DA. Computational analysis of the CB1 carboxyl-terminus in the receptor-G protein complex. Proteins 2016; 84:532-43. [PMID: 26994549 DOI: 10.1002/prot.24999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/07/2016] [Accepted: 01/19/2016] [Indexed: 01/03/2023]
Abstract
Despite the important role of the carboxyl-terminus (Ct) of the activated brain cannabinoid receptor one (CB1) in the regulation of G protein signaling, a structural understanding of interactions with G proteins is lacking. This is largely due to the highly flexible nature of the CB1 Ct that dynamically adapts its conformation to the presence of G proteins. In the present study, we explored how the CB1 Ct can interact with the G protein by building on our prior modeling of the CB1-Gi complex (Shim, Ahn, and Kendall, The Journal of Biological Chemistry 2013;288:32449-32465) to incorporate a complete CB1 Ct (Glu416(Ct)-Leu472(Ct)). Based on the structural constraints from NMR studies, we employed ROSETTA to predict tertiary folds, ZDOCK to predict docking orientation, and molecular dynamics (MD) simulations to obtain two distinct plausible models of CB1 Ct in the CB1-Gi complex. The resulting models were consistent with the NMR-determined helical structure (H9) in the middle region of the CB1 Ct. The CB1 Ct directly interacted with both Gα and Gβ and stabilized the receptor at the Gi interface. The results of site-directed mutagenesis studies of Glu416(Ct), Asp423(Ct), Asp428(Ct), and Arg444(Ct) of CB1 Ct suggested that the CB1 Ct can influence receptor-G protein coupling by stabilizing the receptor at the Gi interface. This research provided, for the first time, models of the CB1 Ct in contact with the G protein.
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Affiliation(s)
- Joong-Youn Shim
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27514
| | - Leepakshi Khurana
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut, 06269-3092
| | - Debra A Kendall
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut, 06269-3092
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32
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Lakkaraju SK, Lemkul JA, Huang J, MacKerell AD. DIRECT-ID: An automated method to identify and quantify conformational variations--application to β2 -adrenergic GPCR. J Comput Chem 2016; 37:416-25. [PMID: 26558323 PMCID: PMC4756637 DOI: 10.1002/jcc.24231] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 09/10/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022]
Abstract
The conformational dynamics of a macromolecule can be modulated by a number of factors, including changes in environment, ligand binding, and interactions with other macromolecules, among others. We present a method that quantifies the differences in macromolecular conformational dynamics and automatically extracts the structural features responsible for these changes. Given a set of molecular dynamics (MD) simulations of a macromolecule, the norms of the differences in covariance matrices are calculated for each pair of trajectories. A matrix of these norms thus quantifies the differences in conformational dynamics across the set of simulations. For each pair of trajectories, covariance difference matrices are parsed to extract structural elements that undergo changes in conformational properties. As a demonstration of its applicability to biomacromolecular systems, the method, referred to as DIRECT-ID, was used to identify relevant ligand-modulated structural variations in the β2 -adrenergic (β2 AR) G-protein coupled receptor. Micro-second MD simulations of the β2 AR in an explicit lipid bilayer were run in the apo state and complexed with the ligands: BI-167107 (agonist), epinephrine (agonist), salbutamol (long-acting partial agonist), or carazolol (inverse agonist). Each ligand modulated the conformational dynamics of β2 AR differently and DIRECT-ID analysis of the inverse-agonist vs. agonist-modulated β2 AR identified residues known through previous studies to selectively propagate deactivation/activation information, along with some previously unidentified ligand-specific microswitches across the GPCR. This study demonstrates the utility of DIRECT-ID to rapidly extract functionally relevant conformational dynamics information from extended MD simulations of large and complex macromolecular systems.
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Affiliation(s)
- Sirish Kaushik Lakkaraju
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Baltimore, MD 21201
| | - Justin A. Lemkul
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Baltimore, MD 21201
| | - Jing Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Baltimore, MD 21201
| | - Alexander D. MacKerell
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Baltimore, MD 21201
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33
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Stumpf AD, Hoffmann C. Optical probes based on G protein-coupled receptors - added work or added value? Br J Pharmacol 2015; 173:255-66. [PMID: 26562218 DOI: 10.1111/bph.13382] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 09/22/2015] [Accepted: 10/26/2015] [Indexed: 12/22/2022] Open
Abstract
In 2003, the first report was published that presented proof of principle for a novel class of FRET biosensors for use in living cells. This novel sensor class was built on the base of GPCRs, which represent an integral transmembrane receptor family passing the membrane seven times and are thus also called the 7TM receptor family. As an estimated number of 30% of all marketed drugs exert their effects by modulating GPCR function, these initial reports promised the gain of novel insights into receptor function. Such FRET sensors have slowly, but progressively, made their way into the standard toolbox for GPCR research as several groups are now reporting on the generation and use of these sensors. By now, FRET sensors have been reported for 18 different GPCRs, and more are expected to be added. These particular receptor sensors have been used to investigate receptor dynamics in living cells to evaluate ligand binding and ligand efficacy in real time, to study voltage and mechanosensitivity of GPCRs or to study the influence of receptor polymorphisms on receptor function in real-time. In this review we will describe the different design principles of these GPCR-based sensors and will summarize their current biological applications in living cells.
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Affiliation(s)
- A D Stumpf
- Bio-Imaging Center, Rudolf-Virchow-Zentrum für Experimentelle Medizin, University of Würzburg, Würzburg, Germany.,Department of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - C Hoffmann
- Bio-Imaging Center, Rudolf-Virchow-Zentrum für Experimentelle Medizin, University of Würzburg, Würzburg, Germany.,Department of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
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34
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Allosteric regulation of G protein-coupled receptor activity by phospholipids. Nat Chem Biol 2015; 12:35-9. [PMID: 26571351 DOI: 10.1038/nchembio.1960] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/25/2015] [Indexed: 01/29/2023]
Abstract
Lipids are emerging as key regulators of membrane protein structure and activity. These effects can be attributed either to the modification of bilayer properties (thickness, curvature and surface tension) or to the binding of specific lipids to the protein surface. For G protein-coupled receptors (GPCRs), the effects of phospholipids on receptor structure and activity remain poorly understood. Here we reconstituted purified β2-adrenergic receptor (β2R) in high-density lipoparticles to systematically characterize the effect of biologically relevant phospholipids on receptor activity. We observed that the lipid headgroup type affected ligand binding (agonist and antagonist) and receptor activation. Specifically, phosphatidylgycerol markedly favored agonist binding and facilitated receptor activation, whereas phosphatidylethanolamine favored antagonist binding and stabilized the inactive state of the receptor. We then showed that these effects could be recapitulated with detergent-solubilized lipids, demonstrating that the functional modulation occurred in the absence of a bilayer. Our data suggest that phospholipids act as direct allosteric modulators of GPCR activity.
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35
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Agonist binding to the NMDA receptor drives movement of its cytoplasmic domain without ion flow. Proc Natl Acad Sci U S A 2015; 112:14705-10. [PMID: 26553997 DOI: 10.1073/pnas.1520023112] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The NMDA receptor (R) plays important roles in brain physiology and pathology as an ion channel. Here we examine the ion flow-independent coupling of agonist to the NMDAR cytoplasmic domain (cd). We measure FRET between fluorescently tagged cytoplasmic domains of GluN1 subunits of NMDARs expressed in neurons. Different neuronal compartments display varying levels of FRET, consistent with different NMDARcd conformations. Agonist binding drives a rapid and transient ion flow-independent reduction in FRET between GluN1 subunits within individual NMDARs. Intracellular infusion of an antibody targeting the GluN1 cytoplasmic domain blocks agonist-driven FRET changes in the absence of ion flow, supporting agonist-driven movement of the NMDARcd. These studies indicate that extracellular ligand binding to the NMDAR can transmit conformational information into the cell in the absence of ion flow.
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36
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Bioorthogonal Labeling of Ghrelin Receptor to Facilitate Studies of Ligand-Dependent Conformational Dynamics. ACTA ACUST UNITED AC 2015; 22:1431-1436. [DOI: 10.1016/j.chembiol.2015.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/21/2015] [Accepted: 09/28/2015] [Indexed: 01/09/2023]
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37
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Wang J, She Y, Wang M, Jin M, Li Y, Wang J, Liu Y. Multiresidue Method for Analysis of β Agonists in Swine Urine by Enzyme Linked Receptor Assay Based on β2 Adrenergic Receptor Expressed in HEK293 Cells. PLoS One 2015; 10:e0139176. [PMID: 26422475 PMCID: PMC4589316 DOI: 10.1371/journal.pone.0139176] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/08/2015] [Indexed: 11/23/2022] Open
Abstract
A novel enzyme-linked receptor assay (ELRA) based on β2-adrenergic receptor (β2-AR) has been developed for rapid and high-throughput detection of β-adrenergic agonists (β-agonists) in urine. Human embryonic kidney cells (HEK293) were introduced as the expression system to enhance the functionality of the recombinant β2-AR, and the attempt to detect β-agonists in swine urine using such approaches was accomplished unprecedentedly. In this article, a recombinant porcine β2-AR was produced in the inner membrane of HEK293 cells and purified from crude membrane protein by nickel-nitrilotriacetic acid affinity chromatography. After activity identification, the recombinant receptor was used in the development of direct competitive ELRA. Several parameters such as blocking buffer and blocking process were optimized and the performance of the system was determined. The IC50 concentrations of clenbuterol, salbutamol, and ractopamine were 34, 53 and 63 μg/L, and the average recovery rates were 68.2%, 60.3% and 65.5%, respectively. ELRA based on β2-AR shows a series of advantages such as safety, easy operation, and high efficiency, making it promising for the rapid screening of β-agonists in animal urine.
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Affiliation(s)
- Jian Wang
- Institute of Quality Standards and Testing Technology for Agro-products of CAAS, Key Laboratory of Agro-Product Quality and Safety, Ministry of Agriculture, Beijing, 100081, P. R. China
- Department of Food Science, Hebei North University, Zhangjiakou, 075000, P. R. China
| | - Yongxin She
- Institute of Quality Standards and Testing Technology for Agro-products of CAAS, Key Laboratory of Agro-Product Quality and Safety, Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Miao Wang
- Institute of Quality Standards and Testing Technology for Agro-products of CAAS, Key Laboratory of Agro-Product Quality and Safety, Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Maojun Jin
- Institute of Quality Standards and Testing Technology for Agro-products of CAAS, Key Laboratory of Agro-Product Quality and Safety, Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Yongfei Li
- Institute of Quality Standards and Testing Technology for Agro-products of CAAS, Key Laboratory of Agro-Product Quality and Safety, Ministry of Agriculture, Beijing, 100081, P. R. China
| | - Jing Wang
- Institute of Quality Standards and Testing Technology for Agro-products of CAAS, Key Laboratory of Agro-Product Quality and Safety, Ministry of Agriculture, Beijing, 100081, P. R. China
- * E-mail:
| | - Yuan Liu
- Department of Food Science, Hebei North University, Zhangjiakou, 075000, P. R. China
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38
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Jatana N, Thukral L, Latha N. Structure and dynamics of DRD4 bound to an agonist and an antagonist using in silico
approaches. Proteins 2015; 83:867-80. [DOI: 10.1002/prot.24716] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 09/15/2014] [Accepted: 09/27/2014] [Indexed: 01/11/2023]
Affiliation(s)
- Nidhi Jatana
- Bioinformatics Infrastructure Facility; Sri Venkateswara College (University of Delhi); Benito Juarez Road Dhaula Kuan New Delhi 110 021 India
| | - Lipi Thukral
- CSIR-Institute of Genomics and Integrative Biology; Mall Road New Delhi 110 007 India
| | - N. Latha
- Bioinformatics Infrastructure Facility; Sri Venkateswara College (University of Delhi); Benito Juarez Road Dhaula Kuan New Delhi 110 021 India
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39
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Woo AYH, Song Y, Zhu W, Xiao RP. Advances in receptor conformation research: the quest for functionally selective conformations focusing on the β2-adrenoceptor. Br J Pharmacol 2015; 172:5477-88. [PMID: 25537131 DOI: 10.1111/bph.13049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 12/14/2014] [Indexed: 01/14/2023] Open
Abstract
Seven-transmembrane receptors, also called GPCRs, represent the largest class of drug targets. Upon ligand binding, a GPCR undergoes conformational rearrangement and thereby changes its interaction with effector proteins including the cognate G-proteins and the multifunctional adaptor proteins, β-arrestins. These proteins, by initiating distinct signal transduction mechanisms, mediate one or several functional responses. Recently, the concept of ligand-directed GPCR signalling, also called functional selectivity or biased agonism, has been proposed to explain the phenomenon that chemically diverse ligands exhibit different efficacies towards the different signalling pathways of a single GPCR, and thereby act as functionally selective or 'biased' ligands. Current concepts support the notion that ligand-specific GPCR conformations are the basis of ligand-directed signalling. Multiple studies using fluorescence spectroscopy, X-ray crystallography, mass spectroscopy, nuclear magnetic resonance spectroscopy, single-molecule force spectroscopy and other techniques have provided the evidence to support this notion. It is anticipated that these techniques will ultimately help elucidate the structural basis of ligand-directed GPCR signalling at a precision meaningful for structure-based drug design and how a specific ligand molecular structure induces a unique receptor conformation leading to biased signalling. In this review, we will summarize recent advances in experimental techniques applied in the study of functionally selective GPCR conformations and breakthrough data obtained in these studies particularly those of the β2-adrenoceptor.
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Affiliation(s)
- Anthony Yiu-Ho Woo
- Institute of Molecular Medicine, Centre for Life Sciences, Peking University, Beijing, China.,Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Ying Song
- Institute of Molecular Medicine, Centre for Life Sciences, Peking University, Beijing, China
| | - Weizhong Zhu
- Department of Pharmacology, Nantong University School of Pharmacy, Nantong, China
| | - Rui-Ping Xiao
- Institute of Molecular Medicine, Centre for Life Sciences, Peking University, Beijing, China.,Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, China
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40
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Fine tuning of sub-millisecond conformational dynamics controls metabotropic glutamate receptors agonist efficacy. Nat Commun 2014; 5:5206. [DOI: 10.1038/ncomms6206] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 09/09/2014] [Indexed: 11/08/2022] Open
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41
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Cao X, Yan J, Shu S, Brzostowski JA, Jin T. Arrestins function in cAR1 GPCR-mediated signaling and cAR1 internalization in the development of Dictyostelium discoideum. Mol Biol Cell 2014; 25:3210-21. [PMID: 25143405 PMCID: PMC4196870 DOI: 10.1091/mbc.e14-03-0834] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Evolutionarily conserved arrestin-like proteins are key components of the cAR1-mediated ERK2 activation that controls cAMP cell–cell signaling during Dictyostelium aggregation. They are also involved in ligand-induced cAR1 internalization, which is required for the switch of cAMP receptors during multicellular development. Oscillation of chemical signals is a common biological phenomenon, but its regulation is poorly understood. At the aggregation stage of Dictyostelium discoideum development, the chemoattractant cAMP is synthesized and released at 6-min intervals, directing cell migration. Although the G protein–coupled cAMP receptor cAR1 and ERK2 are both implicated in regulating the oscillation, the signaling circuit remains unknown. Here we report that D. discoideum arrestins regulate the frequency of cAMP oscillation and may link cAR1 signaling to oscillatory ERK2 activity. Cells lacking arrestins (adcB−C−) display cAMP oscillations during the aggregation stage that are twice as frequent as for wild- type cells. The adcB−C− cells also have a shorter period of transient ERK2 activity and precociously reactivate ERK2 in response to cAMP stimulation. We show that arrestin domain–containing protein C (AdcC) associates with ERK2 and that activation of cAR1 promotes the transient membrane recruitment of AdcC and interaction with cAR1, indicating that arrestins function in cAR1-controlled periodic ERK2 activation and oscillatory cAMP signaling in the aggregation stage of D. discoideum development. In addition, ligand-induced cAR1 internalization is compromised in adcB−C− cells, suggesting that arrestins are involved in elimination of high-affinity cAR1 receptors from cell surface after the aggregation stage of multicellular development.
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Affiliation(s)
- Xiumei Cao
- Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jianshe Yan
- Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China Chemotaxis Signal Section, Laboratory of Immunogenetics, National Institutes of Health, Rockville, MD 20852
| | - Shi Shu
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Joseph A Brzostowski
- Laboratory of Immunogenetics Imaging Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
| | - Tian Jin
- Chemotaxis Signal Section, Laboratory of Immunogenetics, National Institutes of Health, Rockville, MD 20852
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42
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Ceraudo E, Galanth C, Carpentier E, Banegas-Font I, Schonegge AM, Alvear-Perez R, Iturrioz X, Bouvier M, Llorens-Cortes C. Biased signaling favoring gi over β-arrestin promoted by an apelin fragment lacking the C-terminal phenylalanine. J Biol Chem 2014; 289:24599-610. [PMID: 25012663 DOI: 10.1074/jbc.m113.541698] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Apelin plays a prominent role in body fluid and cardiovascular homeostasis. We previously showed that the C-terminal Phe of apelin 17 (K17F) is crucial for triggering apelin receptor internalization and decreasing blood pressure (BP) but is not required for apelin binding or Gi protein coupling. Based on these findings, we hypothesized that the important role of the C-terminal Phe in BP decrease may be as a Gi-independent but β-arrestin-dependent signaling pathway that could involve MAPKs. For this purpose, we have used apelin fragments K17F and K16P (K17F with the C-terminal Phe deleted), which exhibit opposite profiles on apelin receptor internalization and BP. Using BRET-based biosensors, we showed that whereas K17F activates Gi and promotes β-arrestin recruitment to the receptor, K16P had a much reduced ability to promote β-arrestin recruitment while maintaining its Gi activating property, revealing the biased agonist character of K16P. We further show that both β-arrestin recruitment and apelin receptor internalization contribute to the K17F-stimulated ERK1/2 activity, whereas the K16P-promoted ERK1/2 activity is entirely Gi-dependent. In addition to providing new insights on the structural basis underlying the functional selectivity of apelin peptides, our study indicates that the β-arrestin-dependent ERK1/2 activation and not the Gi-dependent signaling may participate in K17F-induced BP decrease.
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Affiliation(s)
- Emilie Ceraudo
- From the Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, INSERM U1050, Paris F-75005, France, the Center for Interdisciplinary Research in Biology, Collège de France, Paris F-75005, France, CNRS, UMR 7241, Paris F-75005, France, and
| | - Cécile Galanth
- From the Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, INSERM U1050, Paris F-75005, France, the Center for Interdisciplinary Research in Biology, Collège de France, Paris F-75005, France, CNRS, UMR 7241, Paris F-75005, France, and
| | - Eric Carpentier
- the Department of Biochemistry, Institute for Research in Immunology and Cancer, and Groupe de Recherche Universitaire sur le Médicament, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Inmaculada Banegas-Font
- From the Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, INSERM U1050, Paris F-75005, France, the Center for Interdisciplinary Research in Biology, Collège de France, Paris F-75005, France, CNRS, UMR 7241, Paris F-75005, France, and
| | - Anne-Marie Schonegge
- the Department of Biochemistry, Institute for Research in Immunology and Cancer, and Groupe de Recherche Universitaire sur le Médicament, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Rodrigo Alvear-Perez
- From the Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, INSERM U1050, Paris F-75005, France, the Center for Interdisciplinary Research in Biology, Collège de France, Paris F-75005, France, CNRS, UMR 7241, Paris F-75005, France, and
| | - Xavier Iturrioz
- From the Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, INSERM U1050, Paris F-75005, France, the Center for Interdisciplinary Research in Biology, Collège de France, Paris F-75005, France, CNRS, UMR 7241, Paris F-75005, France, and
| | - Michel Bouvier
- the Department of Biochemistry, Institute for Research in Immunology and Cancer, and Groupe de Recherche Universitaire sur le Médicament, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Catherine Llorens-Cortes
- From the Laboratory of Central Neuropeptides in the Regulation of Body Fluid Homeostasis and Cardiovascular Functions, INSERM U1050, Paris F-75005, France, the Center for Interdisciplinary Research in Biology, Collège de France, Paris F-75005, France, CNRS, UMR 7241, Paris F-75005, France, and
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43
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Shonberg J, Lopez L, Scammells PJ, Christopoulos A, Capuano B, Lane JR. Biased Agonism at G Protein-Coupled Receptors: The Promise and the Challenges-A Medicinal Chemistry Perspective. Med Res Rev 2014; 34:1286-330. [DOI: 10.1002/med.21318] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Jeremy Shonberg
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University (Parkville Campus); Parkville Victoria Australia
| | - Laura Lopez
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University (Parkville Campus); Parkville Victoria Australia
| | - Peter J. Scammells
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University (Parkville Campus); Parkville Victoria Australia
| | - Arthur Christopoulos
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University (Parkville Campus); Parkville Victoria Australia
| | - Ben Capuano
- Medicinal Chemistry; Monash Institute of Pharmaceutical Sciences; Monash University (Parkville Campus); Parkville Victoria Australia
| | - J. Robert Lane
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University (Parkville Campus); Parkville Victoria Australia
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44
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Abstract
A prerequisite for DNA replication is the unwinding of duplex DNA catalyzed by a replicative hexameric helicase. Despite a growing body of research, key elements of helicase mechanism remain under substantial debate. In particular, the number of DNA strands encircled by the helicase ring during unwinding and the ring orientation at the replication fork completely contrast in contemporary mechanistic models. Here we use single-molecule and ensemble assays to address these questions for the papillomavirus E1 helicase. We find that E1 unwinds DNA with a strand-exclusion mechanism, with the N-terminal side of the helicase ring facing the replication fork. We show that E1 generates strikingly heterogeneous unwinding patterns stemming from varying degrees of repetitive movements, which is modulated by the DNA-binding domain. Together, our studies reveal previously unrecognized dynamic facets of replicative helicase unwinding mechanisms.
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45
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Wang Y, Liu Y, Deberg HA, Nomura T, Hoffman MT, Rohde PR, Schulten K, Martinac B, Selvin PR. Single molecule FRET reveals pore size and opening mechanism of a mechano-sensitive ion channel. eLife 2014; 3:e01834. [PMID: 24550255 PMCID: PMC3925968 DOI: 10.7554/elife.01834] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The mechanosensitive channel of large conductance, which serves as a model system for mechanosensitive channels, has previously been crystallized in the closed form, but not in the open form. Ensemble measurements and electrophysiological sieving experiments show that the open-diameter of the channel pore is >25 Å, but the exact size and whether the conformational change follows a helix-tilt or barrel-stave model are unclear. Here we report measurements of the distance changes on liposome-reconstituted MscL transmembrane α-helices, using a ‘virtual sorting’ single-molecule fluorescence energy transfer. We observed directly that the channel opens via the helix-tilt model and the open pore reaches 2.8 nm in diameter. In addition, based on the measurements, we developed a molecular dynamics model of the channel structure in the open state which confirms our direct observations. DOI:http://dx.doi.org/10.7554/eLife.01834.001 Bacterial cells are full of fluid, and they will burst if they are not able to respond to a build up of pressure. Fortunately, the membrane of a bacterial cell contains channels that can detect the increased mechanical stress on the cell membrane and then open to relieve the pressure. In many bacterial cells, the last defence against the cell exploding is called the mechanosensitive channel of large conductance (MscL). This is made of five proteins, each of which consists of TM1 and TM2 helixes, which are responsible for opening and closing the channel. Two models have been proposed to explain how the channels are opened. In the barrel-stave model, the TM1 helix moves, while the TM2 helix remains stationary. This results in an open pore that is lined with TM1 and TM2 helixes in the same way that wooden staves line a barrel. In the helix-tilt model, both helixes tilt towards the membrane to open the channel. Wang et al. have now used a technique called single-molecule fluorescence resonance energy transfer (FRET) to explore the structure of the open channel in E. coli in order to determine which model is correct. In this technique an individual channel is labeled with two different fluorescent molecules. By illuminating the channel with light of a wavelength that excites the first fluorescent molecule, and measuring the strength of the fluorescence from the second molecule, it is possible to work out the distance between the two molecules. From this, the structure of the channel and how it opens and closes can be explored. Previous attempts to measure the diameters of open channels using fluorescence techniques have suffered from issues caused by the use of large numbers of fluorescent molecules. This has made it necessary to use computational modeling to extract the required data. By looking at a series of individual proteins, Wang et al. overcame these problems and found that the diameter of the fully open pore is 2.8 nm. The result provides strong support for the helix-tilt model. DOI:http://dx.doi.org/10.7554/eLife.01834.002
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Affiliation(s)
- Yong Wang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
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46
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Landomiel F, Gallay N, Jégot G, Tranchant T, Durand G, Bourquard T, Crépieux P, Poupon A, Reiter E. Biased signalling in follicle stimulating hormone action. Mol Cell Endocrinol 2014; 382:452-459. [PMID: 24121199 DOI: 10.1016/j.mce.2013.09.035] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/26/2013] [Accepted: 09/26/2013] [Indexed: 12/22/2022]
Abstract
Follicle-stimulating hormone (FSH) plays a crucial role in the control of reproduction by specifically binding to and activating a membrane receptor (FSHR) that belongs to the G protein-coupled receptor (GPCR) family. Similar to all GPCRs, FSHR activation mechanisms have generally been viewed as a two-state process connecting a unique FSH-bound active receptor to the Gs/cAMP pathway. Over the last decade, paralleling the breakthroughs that were made in the GPCR field, our understanding of FSH actions at the molecular level has dramatically changed. There are numerous facts indicating that the active FSHR is connected to a complex signalling network rather than the sole Gs/cAMP pathway. Consistently, the FSHR probably exists in equilibrium between multiple conformers, a subset of them being stabilized upon ligand binding. Importantly, the nature of the stabilized conformers of the receptor directly depends on the chemical structure of the ligand bound. This implies that it is possible to selectively control the intracellular signalling pathways activated by using biased ligands. Such biased ligands can be of different nature: small chemical molecules, glycosylation variants of the hormone or antibody/hormone complexes. Likewise, mutations or polymorphisms affecting the FSHR can also lead to stabilization of preferential conformers, hence to selective modulation of signalling pathways. These emerging notions offer a new conceptual framework that could potentially lead to the development of more specific drugs while also improving the way FSHR mutants/variants are functionally characterized.
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Affiliation(s)
- Flavie Landomiel
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Nathalie Gallay
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Gwenhael Jégot
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Thibaud Tranchant
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Guillaume Durand
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Thomas Bourquard
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Pascale Crépieux
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Anne Poupon
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France
| | - Eric Reiter
- BIOS group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université François Rabelais, F-37041 Tours, France.
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47
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Sridharan R, Zuber J, Connelly SM, Mathew E, Dumont ME. Fluorescent approaches for understanding interactions of ligands with G protein coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1838:15-33. [PMID: 24055822 PMCID: PMC3926105 DOI: 10.1016/j.bbamem.2013.09.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 09/03/2013] [Accepted: 09/08/2013] [Indexed: 11/18/2022]
Abstract
G protein coupled receptors are responsible for a wide variety of signaling responses in diverse cell types. Despite major advances in the determination of structures of this class of receptors, the underlying mechanisms by which binding of different types of ligands specifically elicits particular signaling responses remain unclear. The use of fluorescence spectroscopy can provide important information about the process of ligand binding and ligand dependent conformational changes in receptors, especially kinetic aspects of these processes that can be difficult to extract from X-ray structures. We present an overview of the extensive array of fluorescent ligands that have been used in studies of G protein coupled receptors and describe spectroscopic approaches for assaying binding and probing the environment of receptor-bound ligands with particular attention to examples involving yeast pheromone receptors. In addition, we discuss the use of fluorescence spectroscopy for detecting and characterizing conformational changes in receptors induced by the binding of ligands. Such studies have provided strong evidence for diversity of receptor conformations elicited by different ligands, consistent with the idea that GPCRs are not simple on and off switches. This diversity of states constitutes an underlying mechanistic basis for biased agonism, the observation that different stimuli can produce different responses from a single receptor. It is likely that continued technical advances will allow fluorescence spectroscopy to play an important role in continued probing of structural transitions in G protein coupled receptors. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding.
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Affiliation(s)
- Rajashri Sridharan
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Jeffrey Zuber
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Sara M. Connelly
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Elizabeth Mathew
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
| | - Mark E. Dumont
- Department of Biochemistry and Biophysics, P.O. Box 712, University of Rochester Medical Center, Rochester, NY 14642
- Department of Pediatrics, P.O. Box 777, University of Rochester Medical Center, Rochester, NY 14642
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48
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Heifetz A, Barker O, Morris GB, Law R, Slack M, Biggin PC. Toward an understanding of agonist binding to human Orexin-1 and Orexin-2 receptors with G-protein-coupled receptor modeling and site-directed mutagenesis. Biochemistry 2013; 52:8246-60. [PMID: 24144388 PMCID: PMC3880013 DOI: 10.1021/bi401119m] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/21/2013] [Indexed: 02/06/2023]
Abstract
The class A G-protein-coupled receptors (GPCRs) Orexin-1 (OX1) and Orexin-2 (OX2) are located predominantly in the brain and are linked to a range of different physiological functions, including the control of feeding, energy metabolism, modulation of neuro-endocrine function, and regulation of the sleep-wake cycle. The natural agonists for OX1 and OX2 are two neuropeptides, Orexin-A and Orexin-B, which have activity at both receptors. Site-directed mutagenesis (SDM) has been reported on both the receptors and the peptides and has provided important insight into key features responsible for agonist activity. However, the structural interpretation of how these data are linked together is still lacking. In this work, we produced and used SDM data, homology modeling followed by MD simulation, and ensemble-flexible docking to generate binding poses of the Orexin peptides in the OX receptors to rationalize the SDM data. We also developed a protein pairwise similarity comparing method (ProS) and a GPCR-likeness assessment score (GLAS) to explore the structural data generated within a molecular dynamics simulation and to help distinguish between different GPCR substates. The results demonstrate how these newly developed methods of structural assessment for GPCRs can be used to provide a working model of neuropeptide-Orexin receptor interaction.
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Affiliation(s)
- Alexander Heifetz
- Evotec
(U.K.) Ltd., 114 Innovation
Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, U.K.
| | - Oliver Barker
- Evotec
(U.K.) Ltd., 114 Innovation
Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, U.K.
| | - G. Benjamin Morris
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.
| | - Richard
J. Law
- Evotec
(U.K.) Ltd., 114 Innovation
Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, U.K.
| | - Mark Slack
- Evotec
AG, Manfred Eigen Campus,
Essener Bogen 7, 22419 Hamburg, Germany
| | - Philip C. Biggin
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.
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49
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Underwood CR, Knudsen LB, Garibay PW, Peters GH, Reedtz-Runge S. Development of a cysteine-deprived and C-terminally truncated GLP-1 receptor. Peptides 2013; 49:100-8. [PMID: 24045233 DOI: 10.1016/j.peptides.2013.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/04/2013] [Accepted: 09/04/2013] [Indexed: 11/20/2022]
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) belongs to family B of the G-protein coupled receptors (GPCRs), and has become a promising target for the treatment of type 2 diabetes. Here we describe the development and characterization of a fully functional cysteine-deprived and C-terminally truncated GLP-1R. Single cysteines were initially substituted with alanine, and functionally redundant cysteines were subsequently changed simultaneously. Our results indicate that Cys(174), Cys(226), Cys(296) and Cys(403) are important for the GLP-1-mediated response, whereas Cys(236), Cys(329), Cys(341), Cys(347), Cys(438), Cys(458) and Cys(462) are not. Extensive deletions were made in the C-terminal tail of GLP-1R in order to determine the limit for truncation. As for other family B GPCRs, we observed a direct correlation between the length of the C-terminal tail and specific binding of (125)I-GLP-1, indicating that the membrane proximal part of the C-terminal is involved in receptor expression at the cell surface. The results show that seven cysteines and more than half of the C-terminal tail can be removed from GLP-1R without compromising GLP-1 binding or function.
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Affiliation(s)
- Christina Rye Underwood
- Department of Incretin Biology, Novo Nordisk, DK-2820 Gentofte, Denmark; Department of Chemistry, MEMPHYS - Center for Biomembrane Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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50
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The complexity of G-protein coupled receptor-ligand interactions. Sci China Chem 2013. [DOI: 10.1007/s11426-013-4911-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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