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Kumar V, Chunchagatta Lakshman PK, Prasad TK, Manjunath K, Bairy S, Vasu AS, Ganavi B, Jasti S, Kamariah N. Target-based drug discovery: Applications of fluorescence techniques in high throughput and fragment-based screening. Heliyon 2024; 10:e23864. [PMID: 38226204 PMCID: PMC10788520 DOI: 10.1016/j.heliyon.2023.e23864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 12/14/2023] [Accepted: 12/14/2023] [Indexed: 01/17/2024] Open
Abstract
Target-based discovery of first-in-class therapeutics demands an in-depth understanding of the molecular mechanisms underlying human diseases. Precise measurements of cellular and biochemical activities are critical to gain mechanistic knowledge of biomolecules and their altered function in disease conditions. Such measurements enable the development of intervention strategies for preventing or treating diseases by modulation of desired molecular processes. Fluorescence-based techniques are routinely employed for accurate and robust measurements of in-vitro activity of molecular targets and for discovering novel chemical molecules that modulate the activity of molecular targets. In the current review, the authors focus on the applications of fluorescence-based high throughput screening (HTS) and fragment-based ligand discovery (FBLD) techniques such as fluorescence polarization (FP), Förster resonance energy transfer (FRET), fluorescence thermal shift assay (FTSA) and microscale thermophoresis (MST) for the discovery of chemical probe to exploring target's role in disease biology and ultimately, serve as a foundation for drug discovery. Some recent advancements in these techniques for compound library screening against important classes of drug targets, such as G-protein-coupled receptors (GPCRs) and GTPases, as well as phosphorylation- and acetylation-mediated protein-protein interactions, are discussed. Overall, this review presents a landscape of how these techniques paved the way for the discovery of small-molecule modulators and biologics against these targets for therapeutic benefits.
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Affiliation(s)
| | | | - Thazhe Kootteri Prasad
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Kavyashree Manjunath
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Sneha Bairy
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Akshaya S. Vasu
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - B. Ganavi
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Subbarao Jasti
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Neelagandan Kamariah
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
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2
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Du R, Li L, Ji J, Fan Y. Receptor-Ligand Binding: Effect of Mechanical Factors. Int J Mol Sci 2023; 24:ijms24109062. [PMID: 37240408 DOI: 10.3390/ijms24109062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/20/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Gaining insight into the in situ receptor-ligand binding is pivotal for revealing the molecular mechanisms underlying the physiological and pathological processes and will contribute to drug discovery and biomedical application. An important issue involved is how the receptor-ligand binding responds to mechanical stimuli. This review aims to provide an overview of the current understanding of the effect of several representative mechanical factors, such as tension, shear stress, stretch, compression, and substrate stiffness on receptor-ligand binding, wherein the biomedical implications are focused. In addition, we highlight the importance of synergistic development of experimental and computational methods for fully understanding the in situ receptor-ligand binding, and further studies should focus on the coupling effects of these mechanical factors.
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Affiliation(s)
- Ruotian Du
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Long Li
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jing Ji
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
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Cevheroğlu O, Murat M, Mingu-Akmete S, Son ÇD. Ste2p Under the Microscope: the Investigation of Oligomeric States of a Yeast G Protein-Coupled Receptor. J Phys Chem B 2021; 125:9526-9536. [PMID: 34433281 DOI: 10.1021/acs.jpcb.1c05872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oligomerization of G protein-coupled receptors (GPCRs) may play important roles in maturation, internalization, signaling, and pharmacology of these receptors. However, the nature and extent of their oligomerization is still under debate. In our study, Ste2p, a yeast mating pheromone GPCR, was tagged with enhanced green fluorescent protein (EGFP), mCherry, and with split florescent protein fragments at the receptor C-terminus. The Förster resonance energy transfer (FRET) technique was used to detect receptors' oligomerization by calculating the energy transfer from EGFP to mCherry. Stimulation of Ste2p oligomers with the receptor ligand did not result in any significant change on observed FRET values. The bimolecular fluorescence complementation (BiFC) assay was combined with FRET to further investigate the tetrameric complexes of Ste2p. Our results suggest that in its quiescent (nonligand-activated) state, Ste2p is found at least as a tetrameric complex on the plasma membrane. Intriguingly, receptor tetramers in their active form showed a significant increase in FRET. This study provides a direct in vivo visualization of Ste2p tetramers and the pheromone effect on the extent of the receptor oligomerization.
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Affiliation(s)
- Orkun Cevheroğlu
- Stem Cell Institute, Ankara University, Cankaya, 06520 Ankara, Turkey
| | - Merve Murat
- Stem Cell Institute, Ankara University, Cankaya, 06520 Ankara, Turkey.,Department of Biological Sciences, Middle East Technical University, Cankaya, 06800 Ankara, Turkey
| | - Sara Mingu-Akmete
- Stem Cell Institute, Ankara University, Cankaya, 06520 Ankara, Turkey.,Department of Biological Sciences, Middle East Technical University, Cankaya, 06800 Ankara, Turkey
| | - Çağdaş D Son
- Department of Biological Sciences, Middle East Technical University, Cankaya, 06800 Ankara, Turkey
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4
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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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5
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Nielsen CDT, Dhasmana D, Floresta G, Wohland T, Cilibrizzi A. Illuminating the Path to Target GPCR Structures and Functions. Biochemistry 2020; 59:3783-3795. [PMID: 32956586 DOI: 10.1021/acs.biochem.0c00606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
G-Protein-coupled receptors (GPCRs) are ubiquitous within eukaryotes, responsible for a wide array of physiological and pathological processes. Indeed, the fact that they are the most drugged target in the human genome is indicative of their importance. Despite the clear interest in GPCRs, most information regarding their activity has been so far obtained by analyzing the response from a "bulk medium". As such, this Perspective summarizes some of the common methods for this indirect observation. Nonetheless, by inspecting approaches applying super-resolution imaging, we argue that imaging is perfectly situated to obtain more detailed structural and spatial information, assisting in the development of new GPCR-targeted drugs and clinical strategies. The benefits of direct optical visualization of GPCRs are analyzed in the context of potential future directions in the field.
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Affiliation(s)
- Christian D-T Nielsen
- Imperial College London, White City Campus, Molecular Sciences Research Hub, 80 Wood Lane, London W12 0BZ, U.K
| | - Divya Dhasmana
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Giuseppe Floresta
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, U.K
| | - Thorsten Wohland
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.,Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Agostino Cilibrizzi
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, U.K
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6
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Zhang S, Gong H, Ge Y, Ye RD. Biased allosteric modulation of formyl peptide receptor 2 leads to distinct receptor conformational states for pro- and anti-inflammatory signaling. Pharmacol Res 2020; 161:105117. [PMID: 32768626 DOI: 10.1016/j.phrs.2020.105117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 07/25/2020] [Accepted: 07/26/2020] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND PURPOSE Formyl peptide receptor 2 (FPR2) is a Class A G protein-coupled receptor (GPCR) that interacts with multiple ligands and transduces both proinflammatory and anti-inflammatory signals. These ligands include weak agonists and modulators that are produced during inflammation. The present study investigates how prolonged exposure to FPR2 modulators influence receptor signaling. EXPERIMENTAL APPROACH Fluorescent biosensors of FPR2 were constructed based on single-molecule fluorescent resonance energy transfer (FRET) and used for measurement of ligand-induced receptor conformational changes. These changes were combined with FPR2-mediated signaling events and used as parameters for the conformational states of FPR2. Ternary complex models were developed to interpret ligand concentration-dependent changes in FPR2 conformational states. KEY RESULTS Incubation with Ac2-26, an anti-inflammatory ligand of FPR2, decreased FRET intensity at picomolar concentrations. In comparison, WKYMVm (W-pep) and Aβ42, both proinflammatory agonists of FPR2, increased FRET intensity. Preincubation with Ac2-26 at 10 pM diminished W-pep-induced Ca2+ flux but potentiated W-pep-stimulated β-arrestin2 membrane translocation and p38 MAPK phosphorylation. The opposite effects were observed with 10 pM of Aβ42. Neither Ac2-26 nor Aβ42 competed for W-pep binding at the picomolar concentrations. CONCLUSIONS AND IMPLICATIONS The results support the presence of two allosteric binding sites on FPR2, each for Ac2-26 and Aβ42, with high and low affinities. Sequential binding of the two allosteric ligands at increasing concentrations induce different conformational changes in FPR2, providing a novel mechanism by which biased allosteric modulators alter receptor conformations and generate pro- and anti-inflammatory signals.
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Affiliation(s)
- Shuo Zhang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hao Gong
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yunjun Ge
- State Key Laboratory for Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, 999078, China
| | - Richard D Ye
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China; State Key Laboratory for Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, 999078, China; Kobilka Institute of Innovative Drug Discovery, School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, China.
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7
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Abstract
Functions of intrinsically disordered proteins do not require structure. Such structure-independent functionality has melted away the classic rigid "lock and key" representation of structure-function relationships in proteins, opening a new page in protein science, where molten keys operate on melted locks and where conformational flexibility and intrinsic disorder, structural plasticity and extreme malleability, multifunctionality and binding promiscuity represent a new-fangled reality. Analysis and understanding of this new reality require novel tools, and some of the techniques elaborated for the examination of intrinsically disordered protein functions are outlined in this review.
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Affiliation(s)
- Vladimir N. Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, 33620, USA
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Russian Federation
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8
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Chemical Probes for the Adenosine Receptors. Pharmaceuticals (Basel) 2019; 12:ph12040168. [PMID: 31726680 PMCID: PMC6958474 DOI: 10.3390/ph12040168] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 12/21/2022] Open
Abstract
Research on the adenosine receptors has been supported by the continuous discovery of new chemical probes characterized by more and more affinity and selectivity for the single adenosine receptor subtypes (A1, A2A, A2B and A3 adenosine receptors). Furthermore, the development of new techniques for the detection of G protein-coupled receptors (GPCR) requires new specific probes. In fact, if in the past radioligands were the most important GPCR probes for detection, compound screening and diagnostic purposes, nowadays, increasing importance is given to fluorescent and covalent ligands. In fact, advances in techniques such as fluorescence resonance energy transfer (FRET) and fluorescent polarization, as well as new applications in flow cytometry and different fluorescence-based microscopic techniques, are at the origin of the extensive research of new fluorescent ligands for these receptors. The resurgence of covalent ligands is due in part to a change in the common thinking in the medicinal chemistry community that a covalent drug is necessarily more toxic than a reversible one, and in part to the useful application of covalent ligands in GPCR structural biology. In this review, an updated collection of available chemical probes targeting adenosine receptors is reported.
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Khurana L, ElGindi M, Tilstam PV, Pantouris G. Elucidating the role of an immunomodulatory protein in cancer: From protein expression to functional characterization. Methods Enzymol 2019; 629:307-360. [PMID: 31727247 DOI: 10.1016/bs.mie.2019.05.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Several fundamental discoveries made over the last two decades, in the field of cancer biology, have increased our understanding of the complex tumor micro- and macroenvironments. This has shifted the current empirical cancer therapies to more rationalized treatments targeting immunomodulatory proteins. From the point of identification, a protein target undergoes several interrogations, which are necessary to truly define its druggability. Here, we outline some basic steps that can be followed for in vitro characterization of a potential immunomodulatory protein target. We describe procedures for recombinant protein expression and purification including key annotations on protein cloning, expression systems, purification strategies and protein characterization using structural and biochemical approaches. For functional characterization, we provide detailed protocols for using flow-cytometric techniques in cell lines or primary cells to study protein expression profiles, proliferation, apoptosis and cell-cycle changes. This multilevel approach can provide valuable, in-depth understanding of any protein target with potential immunomodulatory effects.
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Affiliation(s)
- Leepakshi Khurana
- Department of Pharmacology, School of Medicine, Yale University, New Haven, CT, United States
| | - Mei ElGindi
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Pathricia V Tilstam
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Georgios Pantouris
- Department of Pharmacology, School of Medicine, Yale University, New Haven, CT, United States; Department of Chemistry, University of the Pacific, Stockton, CA, United States.
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10
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Liu Y, Chen LY, Zeng H, Ward R, Wu N, Ma L, Mu X, Li QL, Yang Y, An S, Guo XX, Hao Q, Xu TR. Assessing the real-time activation of the cannabinoid CB1 receptor and the associated structural changes using a FRET biosensor. Int J Biochem Cell Biol 2018; 99:114-124. [PMID: 29626639 DOI: 10.1016/j.biocel.2018.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/25/2018] [Accepted: 04/04/2018] [Indexed: 11/18/2022]
Abstract
The cannabinoid receptor 1 (CB1) is mainly expressed in the nervous system and regulates learning, memory processes, pain and energy metabolism. However, there is no way to directly measure its activation. In this study, we constructed a CB1 intramolecular fluorescence resonance energy transfer (FRET) sensor, which could measure CB1 activation by monitoring structural changes between the third intracellular loop and the C-terminal tail. CB1 agonists induced a time- and concentration-dependent increase in the FRET signal, corresponding to a reduction in the distance between the third intracellular loop and the C-terminal tail. This, in turn, mobilized intracellular Ca2+, inhibited cAMP accumulation, and increased phosphorylation of the ERK1/2 MAP kinases. The activation kinetics detected using this method were consistent with those from previous reports. Moreover, the increased FRET signal was markedly inhibited by the CB1 antagonist rimonabant, which also reduced phosphorylation of the ERK1/2 MAP kinases. We mutated a single cysteine residue in the sensor (at position 257 or 264) to alanine. Both mutation reduced the agonist-induced increase in FRET signal and structural changes in the CB1 receptor, which attenuated phosphorylation of the ERK1/2 MAP kinases. In summary, our sensor directly assesses the kinetics of CB1 activation in real-time and can be used to monitor CB1 structure and function.
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Affiliation(s)
- Ying Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Lu-Yao Chen
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Hong Zeng
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Richard Ward
- Center for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Nan Wu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Li Ma
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Xi Mu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Qiu-Lan Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Yang Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Xiao-Xi Guo
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Qian Hao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Tian-Rui Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China.
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11
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Fungal G-protein-coupled receptors: mediators of pathogenesis and targets for disease control. Nat Microbiol 2018; 3:402-414. [DOI: 10.1038/s41564-018-0127-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/09/2018] [Indexed: 12/31/2022]
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12
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Detection and Quantitative Analysis of Dynamic GPCRs Interactions Using Flow Cytometry-Based FRET. RECEPTOR-RECEPTOR INTERACTIONS IN THE CENTRAL NERVOUS SYSTEM 2018. [DOI: 10.1007/978-1-4939-8576-0_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Hounsou C, Baehr C, Gasparik V, Alili D, Belhocine A, Rodriguez T, Dupuis E, Roux T, Mann A, Heissler D, Pin JP, Durroux T, Bonnet D, Hibert M. From the Promiscuous Asenapine to Potent Fluorescent Ligands Acting at a Series of Aminergic G-Protein-Coupled Receptors. J Med Chem 2017; 61:174-188. [PMID: 29219316 DOI: 10.1021/acs.jmedchem.7b01220] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Monoamine neurotransmitters such as serotonin, dopamine, histamine, and noradrenaline have important and varied physiological functions and similar chemical structures. Representing important pharmaceutical drug targets, the corresponding G-protein-coupled receptors (termed aminergic GPCRs) belong to the class of cell membrane receptors and share many levels of similarity as well. Given their pharmacological and structural closeness, one could hypothesize the possibility to derivatize a ubiquitous ligand to afford rapidly fluorescent probes for a large set of GPCRs to be used for instance in FRET-based binding assays. Here we report fluorescent derivatives of the nonselective agent asenapine which were designed, synthesized, and evaluated as ligands of 34 serotonin, dopamine, histamine, melatonin, acetylcholine, and adrenergic receptors. It appears that this strategy led rapidly to the discovery and development of nanomolar affinity fluorescent probes for 14 aminergic GPCRs. Selected probes were tested in competition binding assays with unlabeled competitors in order to demonstrate their suitability for drug discovery purposes.
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Affiliation(s)
- Candide Hounsou
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Université de Montpellier (IFR3) , 141 Rue de la Cardonille, F-34094 Montpellier Cedex 5, France
| | - Corinne Baehr
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS, Université de Strasbourg , 74 Route du Rhin, 67412 Illkirch, France
| | - Vincent Gasparik
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS, Université de Strasbourg , 74 Route du Rhin, 67412 Illkirch, France
| | - Doria Alili
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Université de Montpellier (IFR3) , 141 Rue de la Cardonille, F-34094 Montpellier Cedex 5, France
| | - Abderazak Belhocine
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Université de Montpellier (IFR3) , 141 Rue de la Cardonille, F-34094 Montpellier Cedex 5, France
| | - Thiéric Rodriguez
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Université de Montpellier (IFR3) , 141 Rue de la Cardonille, F-34094 Montpellier Cedex 5, France
| | - Elodie Dupuis
- Cisbio Bioassays , Parc Marcel Boiteux, BP84175, 30200 Codolet, France
| | - Thomas Roux
- Cisbio Bioassays , Parc Marcel Boiteux, BP84175, 30200 Codolet, France
| | - André Mann
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS, Université de Strasbourg , 74 Route du Rhin, 67412 Illkirch, France
| | - Denis Heissler
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS, Université de Strasbourg , 74 Route du Rhin, 67412 Illkirch, France.,LabEx Medalis, Université de Strasbourg , 67000 Strasbourg, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Université de Montpellier (IFR3) , 141 Rue de la Cardonille, F-34094 Montpellier Cedex 5, France
| | - Thierry Durroux
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Université de Montpellier (IFR3) , 141 Rue de la Cardonille, F-34094 Montpellier Cedex 5, France
| | - Dominique Bonnet
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS, Université de Strasbourg , 74 Route du Rhin, 67412 Illkirch, France.,LabEx Medalis, Université de Strasbourg , 67000 Strasbourg, France
| | - Marcel Hibert
- Laboratoire d'Innovation Thérapeutique, Faculté de Pharmacie, UMR7200 CNRS, Université de Strasbourg , 74 Route du Rhin, 67412 Illkirch, France.,LabEx Medalis, Université de Strasbourg , 67000 Strasbourg, France
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14
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Spatial intensity distribution analysis quantifies the extent and regulation of homodimerization of the secretin receptor. Biochem J 2017; 474:1879-1895. [PMID: 28424368 PMCID: PMC5442643 DOI: 10.1042/bcj20170184] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 01/02/2023]
Abstract
Previous studies have indicated that the G-protein-coupled secretin receptor is present as a homodimer, organized through symmetrical contacts in transmembrane domain IV, and that receptor dimerization is critical for high-potency signalling by secretin. However, whether all of the receptor exists in the dimeric form or if this is regulated is unclear. We used measures of quantal brightness of the secretin receptor tagged with monomeric enhanced green fluorescent protein (mEGFP) and spatial intensity distribution analysis to assess this. Calibration using cells expressing plasma membrane-anchored forms of mEGFP initially allowed us to demonstrate that the epidermal growth factor receptor is predominantly monomeric in the absence of ligand and while wild-type receptor was rapidly converted into a dimeric form by ligand, a mutated form of this receptor remained monomeric. Equivalent studies showed that, at moderate expression levels, the secretin receptor exists as a mixture of monomeric and dimeric forms, with little evidence of higher-order complexity. However, sodium butyrate-induced up-regulation of the receptor resulted in a shift from monomeric towards oligomeric organization. In contrast, a form of the secretin receptor containing a pair of mutations on the lipid-facing side of transmembrane domain IV was almost entirely monomeric. Down-regulation of the secretin receptor-interacting G-protein Gαs did not alter receptor organization, indicating that dimerization is defined specifically by direct protein–protein interactions between copies of the receptor polypeptide, while short-term treatment with secretin had no effect on organization of the wild-type receptor but increased the dimeric proportion of the mutated receptor variant.
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15
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Methods used to study the oligomeric structure of G-protein-coupled receptors. Biosci Rep 2017; 37:BSR20160547. [PMID: 28062602 PMCID: PMC5398257 DOI: 10.1042/bsr20160547] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 02/02/2023] Open
Abstract
G-protein-coupled receptors (GPCRs), which constitute the largest family of cell surface receptors, were originally thought to function as monomers, but are now recognized as being able to act in a wide range of oligomeric states and indeed, it is known that the oligomerization state of a GPCR can modulate its pharmacology and function. A number of experimental techniques have been devised to study GPCR oligomerization including those based upon traditional biochemistry such as blue-native PAGE (BN-PAGE), co-immunoprecipitation (Co-IP) and protein-fragment complementation assays (PCAs), those based upon resonance energy transfer, FRET, time-resolved FRET (TR-FRET), FRET spectrometry and bioluminescence resonance energy transfer (BRET). Those based upon microscopy such as FRAP, total internal reflection fluorescence microscopy (TIRFM), spatial intensity distribution analysis (SpIDA) and various single molecule imaging techniques. Finally with the solution of a growing number of crystal structures, X-ray crystallography must be acknowledged as an important source of discovery in this field. A different, but in many ways complementary approach to the use of more traditional experimental techniques, are those involving computational methods that possess obvious merit in the study of the dynamics of oligomer formation and function. Here, we summarize the latest developments that have been made in the methods used to study GPCR oligomerization and give an overview of their application.
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16
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Link R, Veiksina S, Rinken A, Kopanchuk S. Characterization of ligand binding to melanocortin 4 receptors using fluorescent peptides with improved kinetic properties. Eur J Pharmacol 2017; 799:58-66. [DOI: 10.1016/j.ejphar.2017.01.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 12/24/2022]
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17
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Teilum K, Kunze MBA, Erlendsson S, Kragelund BB. (S)Pinning down protein interactions by NMR. Protein Sci 2017; 26:436-451. [PMID: 28019676 PMCID: PMC5326574 DOI: 10.1002/pro.3105] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 12/14/2016] [Accepted: 12/14/2016] [Indexed: 11/29/2022]
Abstract
Protein molecules are highly diverse communication platforms and their interaction repertoire stretches from atoms over small molecules such as sugars and lipids to macromolecules. An important route to understanding molecular communication is to quantitatively describe their interactions. These types of analyses determine the amounts and proportions of individual constituents that participate in a reaction as well as their rates of reactions and their thermodynamics. Although many different methods are available, there is currently no single method able to quantitatively capture and describe all types of protein reactions, which can span orders of magnitudes in affinities, reaction rates, and lifetimes of states. As the more versatile technique, solution NMR spectroscopy offers a remarkable catalogue of methods that can be successfully applied to the quantitative as well as qualitative descriptions of protein interactions. In this review we provide an easy-access approach to NMR for the non-NMR specialist and describe how and when solution state NMR spectroscopy is the method of choice for addressing protein ligand interaction. We describe very briefly the theoretical background and illustrate simple protein-ligand interactions as well as typical strategies for measuring binding constants using NMR spectroscopy. Finally, this review provides examples of caveats of the method as well as the options to improve the outcome of an NMR analysis of a protein interaction reaction.
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Affiliation(s)
- Kaare Teilum
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
| | - Micha Ben Achim Kunze
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
| | - Simon Erlendsson
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
| | - Birthe B. Kragelund
- Structural Biology and NMR LaboratoryThe Linderstrøm‐Lang Centre for Protein Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, DK‐2200Copenhagen NDenmark
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18
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Stoddart LA, White CW, Nguyen K, Hill SJ, Pfleger KDG. Fluorescence- and bioluminescence-based approaches to study GPCR ligand binding. Br J Pharmacol 2016; 173:3028-37. [PMID: 26317175 PMCID: PMC5125978 DOI: 10.1111/bph.13316] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/01/2015] [Accepted: 08/20/2015] [Indexed: 01/15/2023] Open
Abstract
Ligand binding is a vital component of any pharmacologist's toolbox and allows the detailed investigation of how a molecule binds to its receptor. These studies enable the experimental determination of binding affinity of labelled and unlabelled compounds through kinetic, saturation (Kd ) and competition (Ki ) binding assays. Traditionally, these studies have used molecules labelled with radioisotopes; however, more recently, fluorescent ligands have been developed for this purpose. This review will briefly cover receptor ligand binding theory and then discuss the use of fluorescent ligands with some of the different technologies currently employed to examine ligand binding. Fluorescent ligands can be used for direct measurement of receptor-associated fluorescence using confocal microscopy and flow cytometry as well as in assays such as fluorescence polarization, where ligand binding is monitored by changes in the free rotation when a fluorescent ligand is bound to a receptor. Additionally, fluorescent ligands can act as donors or acceptors for fluorescence resonance energy transfer (FRET) with the development of assays based on FRET and time-resolved FRET (TR-FRET). Finally, we have recently developed a novel bioluminescence resonance energy transfer (BRET) ligand binding assay utilizing a small (19 kDa), super-bright luciferase subunit (NanoLuc) from a deep sea shrimp. In combination with fluorescent ligands, measurement of RET now provides an array of methodologies to study ligand binding. While each method has its own advantages and drawbacks, binding studies using fluorescent ligands are now a viable alternative to the use of radioligands. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- Leigh A Stoddart
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Carl W White
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Kim Nguyen
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Stephen J Hill
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Nottingham, UK
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
- Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.
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19
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Thermodynamic and kinetic characterization of pH-dependent interactions between bovine serum albumin and ibuprofen in 2D and 3D systems. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.05.090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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20
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Gabl M, Holdfeldt A, Winther M, Oprea T, Bylund J, Dahlgren C, Forsman H. A pepducin designed to modulate P2Y2R function interacts with FPR2 in human neutrophils and transfers ATP to an NADPH-oxidase-activating ligand through a receptor cross-talk mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1228-37. [PMID: 26996596 DOI: 10.1016/j.bbamcr.2016.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 01/05/2023]
Abstract
Several G-protein-coupled receptors (GPCRs) can be activated or inhibited in a specific manner by membrane-permeable pepducins, which are short palmitoylated peptides with amino acid sequences identical to an intracellular domain of the receptor to be targeted. Unlike the endogenous P2Y2R agonist ATP, the P2Y2PalIC2 pepducin, which has an amino acid sequence corresponding to the second intracellular loop of the human ATP receptor (P2Y2R), activated the superoxide anion-generating NADPH-oxidase in neutrophils. In addition to having a direct effect on neutrophils, the P2Y2R pepducin converted naïve neutrophils to a primed state, which secondarily responded to ATP by producing superoxide. A pepducin with a peptide identical to the third intracellular loop of P2Y2R (P2Y2PalIC3) exhibited the same basic functions as P2Y2PalIC2, whereas one with a peptide that was identical to the first intracellular loop (P2Y2PalIC1) lacked these functions. The responses induced in neutrophils by the P2Y2R pepducins were not inhibited by the P2Y2R antagonist AR-C118925, and the receptor desensitization profile suggested the involvement of FPR2 rather than P2Y2R. Accordingly, antagonists/inhibitors of FPR2 attenuated the activities of the P2Y2R pepducins, which also selectively activated FPR2-overexpressing cells. In summary, we show that pepducins supposed to target P2Y2R activate human neutrophils through FPR2. We also show that the P2Y2PalIC2 pepducin can convert ATP from a non-activating agent to a potent neutrophil NADPH-oxidase activator. The molecular basis of this phenomenon involves cross-talk between the receptor/ligand pairs of P2Y2R/ATP and FPR2/P2Y2-pepducin.
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Affiliation(s)
- Michael Gabl
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - André Holdfeldt
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Malene Winther
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Tudor Oprea
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden; Translational Informatics Division, UNM Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Johan Bylund
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Claes Dahlgren
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
| | - Huamei Forsman
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden
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21
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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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22
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Ursu A, Waldmann H. Hide and seek: Identification and confirmation of small molecule protein targets. Bioorg Med Chem Lett 2015; 25:3079-86. [PMID: 26115575 DOI: 10.1016/j.bmcl.2015.06.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 06/01/2015] [Accepted: 06/04/2015] [Indexed: 12/14/2022]
Abstract
Target identification and confirmation for small molecules is often the rate limiting step in drug discovery. A robust method to identify proteins addressed by small molecules is affinity chromatography using chemical probes. These usually consist of the compound of interest equipped with a linker molecule and a proper tag. Recently, methods emerged that allow the identification of protein targets without prior functionalization of the small molecule of interest. The digest offers an update on the newest developments in the area of target identification with special focus on confirmation techniques.
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Affiliation(s)
- Andrei Ursu
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany; Chemical Biology, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 6, 44221 Dortmund, Germany
| | - Herbert Waldmann
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany; Chemical Biology, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 6, 44221 Dortmund, Germany.
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23
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Liste MJV, Caltabiano G, Ward RJ, Alvarez-Curto E, Marsango S, Milligan G. The molecular basis of oligomeric organization of the human M3 muscarinic acetylcholine receptor. Mol Pharmacol 2015; 87:936-53. [PMID: 25769304 DOI: 10.1124/mol.114.096925] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/13/2015] [Indexed: 11/22/2022] Open
Abstract
G protein-coupled receptors, including the M3 muscarinic acetylcholine receptor, can form homo-oligomers. However, the basis of these interactions and the overall organizational structure of such oligomers are poorly understood. Combinations of site-directed mutagenesis and homogenous time-resolved fluorescence resonance energy transfer studies that assessed interactions between receptor protomers at the surface of transfected cells indicated important contributions of regions of transmembrane domains I, IV, V, VI, and VII as well as intracellular helix VIII to the overall organization. Molecular modeling studies based on both these results and an X-ray structure of the inactive state of the M3 receptor bound by the antagonist/inverse agonist tiotropium were then employed. The results could be accommodated fully by models in which a proportion of the cell surface M3 receptor population is a tetramer with rhombic, but not linear, orientation. This is consistent with previous studies based on spectrally resolved, multiphoton fluorescence resonance energy transfer. Modeling studies furthermore suggest an important role for molecules of cholesterol at the dimer + dimer interface of the tetramer, which is consistent with the presence of cholesterol at key locations in many G protein-coupled receptor crystal structures. Mutants that displayed disrupted quaternary organization were often poorly expressed and showed immature N-glycosylation. Sustained treatment of cells expressing such mutants with the muscarinic receptor inverse agonist atropine increased cellular levels and restored both cell surface delivery and quaternary organization to many of the mutants. These observations suggest that organization as a tetramer may occur before plasma membrane delivery and may be a key step in cellular quality control assessment.
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Affiliation(s)
- María José Varela Liste
- Molecular Pharmacology Group, Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom (M.J.V.L., G.C., R.J.W., E.A.-C., S.M., G.M.), and Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain (G.C.)
| | - Gianluigi Caltabiano
- Molecular Pharmacology Group, Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom (M.J.V.L., G.C., R.J.W., E.A.-C., S.M., G.M.), and Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain (G.C.)
| | - Richard J Ward
- Molecular Pharmacology Group, Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom (M.J.V.L., G.C., R.J.W., E.A.-C., S.M., G.M.), and Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain (G.C.)
| | - Elisa Alvarez-Curto
- Molecular Pharmacology Group, Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom (M.J.V.L., G.C., R.J.W., E.A.-C., S.M., G.M.), and Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain (G.C.)
| | - Sara Marsango
- Molecular Pharmacology Group, Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom (M.J.V.L., G.C., R.J.W., E.A.-C., S.M., G.M.), and Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain (G.C.)
| | - Graeme Milligan
- Molecular Pharmacology Group, Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom (M.J.V.L., G.C., R.J.W., E.A.-C., S.M., G.M.), and Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain (G.C.)
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24
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Naganathan S, Ray-Saha S, Park M, Tian H, Sakmar TP, Huber T. Multiplex detection of functional G protein-coupled receptors harboring site-specifically modified unnatural amino acids. Biochemistry 2015; 54:776-86. [PMID: 25524496 PMCID: PMC4310623 DOI: 10.1021/bi501267x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
We developed a strategy for identifying
positions in G protein-coupled
receptors that are amenable to bioorthogonal modification with a peptide
epitope tag under cell culturing conditions. We introduced the unnatural
amino acid p-azido-l-phenylalanine (azF)
into human CC chemokine receptor 5 (CCR5) at site-specific amber codon
mutations. We then used strain-promoted azide–alkyne [3+2]
cycloaddition to label the azF-CCR5 variants with a FLAG peptide epitope-conjugated
aza-dibenzocyclooctyne (DBCO) reagent. A microtiter plate-based sandwich
fluorophore-linked immunosorbent assay was used to probe simultaneously
the FLAG epitope and the receptor using infrared dye-conjugated antibodies
so that the extent of DBCO incorporation, corresponding nominally
to labeling efficiency, could be quantified ratiometrically. The extent
of incorporation of DBCO at the various sites was evaluated in the
context of a recent crystal structure of maraviroc-bound CCR5. We
observed that labeling efficiency varied dramatically depending on
the topological location of the azF in CCR5. Interestingly, position
109 in transmembrane helix 3, located in a hydrophobic cavity on the
extracellular side of the receptor, was labeled most efficiently.
Because the bioorthogonal labeling and detection strategy described
might be used to introduce a variety of different peptide epitopes
or fluorophores into engineered expressed receptors, it might prove
to be useful for a wide range of applications, including single-molecule
detection studies of receptor trafficking and signaling mechanism.
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Affiliation(s)
- Saranga Naganathan
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University , New York, New York 10065, United States
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25
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Zakrys L, Ward RJ, Pediani JD, Godin AG, Graham GJ, Milligan G. Roundabout 1 exists predominantly as a basal dimeric complex and this is unaffected by binding of the ligand Slit2. Biochem J 2014; 461:61-73. [PMID: 24673457 DOI: 10.1042/bj20140190] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Robo (Roundabout) receptors and their Slit polypeptide ligands are known to play key roles in neuronal development and have been implicated in both angiogenesis and cancer. Like the other family members, Robo1 is a large single transmembrane domain polypeptide containing a series of well-defined extracellular elements. However, the intracellular domain lacks structural definition and little is known about the quaternary structure of Robo receptors or how binding of a Slit might affect this. To address these questions combinations of both autofluorescent protein-based FRET imaging and time-resolved FRET were employed. Both approaches identified oligomeric organization of Robo1 that did not require the presence of the intracellular domain. SpIDA (spatial intensity distribution analysis) of eGFP-tagged forms of Robo1 indicated that for a C-terminally deleted version approximately two-thirds of the receptor was present as a dimer and one-third as a monomer. By contrast, full-length Robo1 was present almost exclusively as a dimer. In each case this was unaffected by the addition of Slit2, although parallel studies demonstrated the biological activity of Slit2 and its interaction with Robo1. Deletion of both the immunoglobulin and fibronectin type III extracellular repeats prevented dimer formation, with the immunoglobulin repeats providing the bulk of the protein-protein interaction affinity.
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Affiliation(s)
| | - Richard J Ward
- *Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
| | - John D Pediani
- *Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
| | - Antoine G Godin
- ‡Laboratoire Photonique, Numérique et Nanosciences (LP2N) Institut d'Optique Graduate School, CNRS and Université Bordeaux, 351 cours de la libération, 33405 Talence Cedex, France
| | - Gerard J Graham
- †Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
| | - Graeme Milligan
- *Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
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