1
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Tse LH, Wong YH. Modeling the Heterodimer Interfaces of Melatonin Receptors. Front Cell Neurosci 2021; 15:725296. [PMID: 34690701 PMCID: PMC8529217 DOI: 10.3389/fncel.2021.725296] [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: 06/15/2021] [Accepted: 08/16/2021] [Indexed: 11/16/2022] Open
Abstract
Melatonin receptors are Class A G protein-coupled receptors (GPCRs) that regulate a plethora of physiological activities in response to the rhythmic secretion of melatonin from the pineal gland. Melatonin is a key regulator in the control of circadian rhythm and has multiple functional roles in retinal physiology, memory, immunomodulation and tumorigenesis. The two subtypes of human melatonin receptors, termed MT1 and MT2, utilize overlapping signaling pathways although biased signaling properties have been reported in some cellular systems. With the emerging concept of GPCR dimerization, melatonin receptor heterodimers have been proposed to participate in system-biased signaling. Here, we used computational approaches to map the dimerization interfaces of known heterodimers of melatonin receptors, including MT1/MT2, MT1/GPR50, MT2/GPR50, and MT2/5-HT2C. By homology modeling and membrane protein docking analyses, we have identified putative preferred interface interactions within the different pairs of melatonin receptor dimers and provided plausible structural explanations for some of the unique pharmacological features of specific heterodimers previously reported. A thorough understanding of the molecular basis of melatonin receptor heterodimers may enable the development of new therapeutic approaches against aliments involving these heterodimeric receptors.
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Affiliation(s)
- Lap Hang Tse
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, SAR China
| | - Yung Hou Wong
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, SAR China.,State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, SAR China.,Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, SAR China
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2
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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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3
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Jia Y, Bleicher F, Reboulet J, Merabet S. Bimolecular Fluorescence Complementation (BiFC) and Multiplexed Imaging of Protein-Protein Interactions in Human Living Cells. Methods Mol Biol 2021; 2350:173-190. [PMID: 34331286 DOI: 10.1007/978-1-0716-1593-5_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Deciphering protein-protein interactions (PPIs) in vivo is crucial to understand protein function. Bimolecular fluorescence complementation (BiFC) makes applicable the analysis of PPIs in many different native contexts, including human live cells. It relies on the property of monomeric fluorescent proteins to be reconstituted from two separate subfragments upon spatial proximity. Candidate partners fused to such complementary subfragments can form a fluorescent protein complex upon interaction, allowing visualization of weak and transient PPIs. It can also be applied for investigation of distinct PPIs at the same time using a multicolor setup. In this chapter, we provide a detailed protocol for analyzing PPIs by doing BiFC in cultured cells. Proof-of-principle experiments rely on the complementation property between the N-terminal fragment of mVenus (designated VN173) and the C-terminal fragment of mCerulean (designated CC155) and the partnership between HOXA7 and PBX1 proteins. This protocol is compatible with any other fluorescent complementation pair fragments and any type of candidate interacting proteins.
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Affiliation(s)
- Yunlong Jia
- Institut de Génomique Fonctionnelle de Lyon, UMR5242, Université Lyon 1, CNRS, Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France
| | - Françoise Bleicher
- Institut de Génomique Fonctionnelle de Lyon, UMR5242, Université Lyon 1, CNRS, Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France
| | - Jonathan Reboulet
- Institut de Génomique Fonctionnelle de Lyon, UMR5242, Université Lyon 1, CNRS, Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France
| | - Samir Merabet
- Institut de Génomique Fonctionnelle de Lyon, UMR5242, Université Lyon 1, CNRS, Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France.
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4
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Sebastianutto I, Goyet E, Andreoli L, Font-Ingles J, Moreno-Delgado D, Bouquier N, Jahannault-Talignani C, Moutin E, Di Menna L, Maslava N, Pin JP, Fagni L, Nicoletti F, Ango F, Cenci MA, Perroy J. D1-mGlu5 heteromers mediate noncanonical dopamine signaling in Parkinson's disease. J Clin Invest 2020; 130:1168-1184. [PMID: 32039920 DOI: 10.1172/jci126361] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 11/26/2019] [Indexed: 12/21/2022] Open
Abstract
Dopamine receptor D1 modulates glutamatergic transmission in cortico-basal ganglia circuits and represents a major target of L-DOPA therapy in Parkinson's disease. Here we show that D1 and metabotropic glutamate type 5 (mGlu5) receptors can form previously unknown heteromeric entities with distinctive functional properties. Interacting with Gq proteins, cell-surface D1-mGlu5 heteromers exacerbated PLC signaling and intracellular calcium release in response to either glutamate or dopamine. In rodent models of Parkinson's disease, D1-mGlu5 nanocomplexes were strongly upregulated in the dopamine-denervated striatum, resulting in a synergistic activation of PLC signaling by D1 and mGlu5 receptor agonists. In turn, D1-mGlu5-dependent PLC signaling was causally linked with excessive activation of extracellular signal-regulated kinases in striatal neurons, leading to dyskinesia in animals treated with L-DOPA or D1 receptor agonists. The discovery of D1-mGlu5 functional heteromers mediating maladaptive molecular and motor responses in the dopamine-denervated striatum may prompt the development of new therapeutic principles for Parkinson's disease.
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Affiliation(s)
- Irene Sebastianutto
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Elise Goyet
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Laura Andreoli
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Joan Font-Ingles
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - David Moreno-Delgado
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Department of Neuroscience Research, UCB Pharma, Braine l'Alleud, Belgium
| | - Nathalie Bouquier
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | | | - Enora Moutin
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Luisa Di Menna
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, Pozzilli, Italy
| | - Natallia Maslava
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Laurent Fagni
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Ferdinando Nicoletti
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Fabrice Ango
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - M Angela Cenci
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Julie Perroy
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
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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: 3] [Impact Index Per Article: 0.8] [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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Luminescence- and Fluorescence-Based Complementation Assays to Screen for GPCR Oligomerization: Current State of the Art. Int J Mol Sci 2019; 20:ijms20122958. [PMID: 31213021 PMCID: PMC6627893 DOI: 10.3390/ijms20122958] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/05/2019] [Accepted: 06/12/2019] [Indexed: 01/22/2023] Open
Abstract
G protein-coupled receptors (GPCRs) have the propensity to form homo- and heterodimers. Dysfunction of these dimers has been associated with multiple diseases, e.g., pre-eclampsia, schizophrenia, and depression, among others. Over the past two decades, considerable efforts have been made towards the development of screening assays for studying these GPCR dimer complexes in living cells. As a first step, a robust in vitro assay in an overexpression system is essential to identify and characterize specific GPCR–GPCR interactions, followed by methodologies to demonstrate association at endogenous levels and eventually in vivo. This review focuses on protein complementation assays (PCAs) which have been utilized to study GPCR oligomerization. These approaches are typically fluorescence- and luminescence-based, making identification and localization of protein–protein interactions feasible. The GPCRs of interest are fused to complementary fluorescent or luminescent fragments that, upon GPCR di- or oligomerization, may reconstitute to a functional reporter, of which the activity can be measured. Various protein complementation assays have the disadvantage that the interaction between the reconstituted split fragments is irreversible, which can lead to false positive read-outs. Reversible systems offer several advantages, as they do not only allow to follow the kinetics of GPCR–GPCR interactions, but also allow evaluation of receptor complex modulation by ligands (either agonists or antagonists). Protein complementation assays may be used for high throughput screenings as well, which is highly relevant given the growing interest and effort to identify small molecule drugs that could potentially target disease-relevant dimers. In addition to providing an overview on how PCAs have allowed to gain better insights into GPCR–GPCR interactions, this review also aims at providing practical guidance on how to perform PCA-based assays.
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7
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Borroto-Escuela DO, Rodriguez D, Romero-Fernandez W, Kapla J, Jaiteh M, Ranganathan A, Lazarova T, Fuxe K, Carlsson J. Mapping the Interface of a GPCR Dimer: A Structural Model of the A 2A Adenosine and D 2 Dopamine Receptor Heteromer. Front Pharmacol 2018; 9:829. [PMID: 30214407 PMCID: PMC6125358 DOI: 10.3389/fphar.2018.00829] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/10/2018] [Indexed: 12/17/2022] Open
Abstract
The A2A adenosine (A2AR) and D2 dopamine (D2R) receptors form oligomers in the cell membrane and allosteric interactions across the A2AR–D2R heteromer represent a target for development of drugs against central nervous system disorders. However, understanding of the molecular determinants of A2AR–D2R heteromerization and the allosteric antagonistic interactions between the receptor protomers is still limited. In this work, a structural model of the A2AR–D2R heterodimer was generated using a combined experimental and computational approach. Regions involved in the heteromer interface were modeled based on the effects of peptides derived from the transmembrane (TM) helices on A2AR–D2R receptor–receptor interactions in bioluminescence resonance energy transfer (BRET) and proximity ligation assays. Peptides corresponding to TM-IV and TM-V of the A2AR blocked heterodimer interactions and disrupted the allosteric effect of A2AR activation on D2R agonist binding. Protein–protein docking was used to construct a model of the A2AR–D2R heterodimer with a TM-IV/V interface, which was refined using molecular dynamics simulations. Mutations in the predicted interface reduced A2AR–D2R interactions in BRET experiments and altered the allosteric modulation. The heterodimer model provided insights into the structural basis of allosteric modulation and the technique developed to characterize the A2AR–D2R interface can be extended to study the many other G protein-coupled receptors that engage in heteroreceptor complexes.
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Affiliation(s)
| | - David Rodriguez
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Wilber Romero-Fernandez
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Jon Kapla
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Mariama Jaiteh
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Anirudh Ranganathan
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Tzvetana Lazarova
- Department of Biochemistry and Molecular Biology, Institute of Neuroscience, Faculty of Medicine, Autonomous University of Barcelona, Barcelona, Spain
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Jens Carlsson
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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8
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Wang S, Ding M, Chen X, Chang L, Sun Y. Development of bimolecular fluorescence complementation using rsEGFP2 for detection and super-resolution imaging of protein-protein interactions in live cells. BIOMEDICAL OPTICS EXPRESS 2017; 8:3119-3131. [PMID: 28663931 PMCID: PMC5480454 DOI: 10.1364/boe.8.003119] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/12/2017] [Accepted: 05/12/2017] [Indexed: 05/28/2023]
Abstract
Direct visualization of protein-protein interactions (PPIs) at high spatial and temporal resolution in live cells is crucial for understanding the intricate and dynamic behaviors of signaling protein complexes. Recently, bimolecular fluorescence complementation (BiFC) assays have been combined with super-resolution imaging techniques including PALM and SOFI to visualize PPIs at the nanometer spatial resolution. RESOLFT nanoscopy has been proven as a powerful live-cell super-resolution imaging technique. With regard to the detection and visualization of PPIs in live cells with high temporal and spatial resolution, here we developed a BiFC assay using split rsEGFP2, a highly photostable and reversibly photoswitchable fluorescent protein previously developed for RESOLFT nanoscopy. Combined with parallelized RESOLFT microscopy, we demonstrated the high spatiotemporal resolving capability of a rsEGFP2-based BiFC assay by detecting and visualizing specifically the heterodimerization interactions between Bcl-xL and Bak as well as the dynamics of the complex on mitochondria membrane in live cells.
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Affiliation(s)
- Sheng Wang
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- Contributed equally to this work
| | - Miao Ding
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- Contributed equally to this work
| | - Xuanze Chen
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
- Contributed equally to this work
| | - Lei Chang
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
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9
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Brust TF, Conley JM, Watts VJ. Gα(i/o)-coupled receptor-mediated sensitization of adenylyl cyclase: 40 years later. Eur J Pharmacol 2015; 763:223-32. [PMID: 25981304 DOI: 10.1016/j.ejphar.2015.05.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/02/2015] [Accepted: 05/11/2015] [Indexed: 12/20/2022]
Abstract
Heterologous sensitization of adenylyl cyclase (also referred to as superactivation, sensitization, or supersensitization of adenylyl cyclase) is a cellular adaptive response first described 40 years ago in the laboratory of Dr. Marshall Nirenberg. This apparently paradoxical cellular response occurs following persistent activation of Gαi/o-coupled receptors and causes marked enhancement in the activity of adenylyl cyclases, thereby increasing cAMP production. Since our last review in 2005, significant progress in the field has led to a better understanding of the relevance of, and the cellular biochemical processes that occur during the development and expression of heterologous sensitization. In this review we will discuss the recent advancements in the field and the mechanistic hypotheses on heterologous sensitization.
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Affiliation(s)
- Tarsis F Brust
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA
| | - Jason M Conley
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA.
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10
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Midde KK, Aznar N, Laederich MB, Ma GS, Kunkel MT, Newton AC, Ghosh P. Multimodular biosensors reveal a novel platform for activation of G proteins by growth factor receptors. Proc Natl Acad Sci U S A 2015; 112:E937-46. [PMID: 25713130 PMCID: PMC4352799 DOI: 10.1073/pnas.1420140112] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Environmental cues are transmitted to the interior of the cell via a complex network of signaling hubs. Receptor tyrosine kinases (RTKs) and trimeric G proteins are two such major signaling hubs in eukaryotes. Conventionally, canonical signal transduction via trimeric G proteins is thought to be triggered exclusively by G protein-coupled receptors. Here we used molecular engineering to develop modular fluorescent biosensors that exploit the remarkable specificity of bimolecular recognition, i.e., of both G proteins and RTKs, and reveal the workings of a novel platform for activation of G proteins by RTKs in single living cells. Comprised of the unique modular makeup of guanidine exchange factor Gα-interacting vesicle-associated protein (GIV)/girdin, a guanidine exchange factor that links G proteins to a variety of RTKs, these biosensors provide direct evidence that RTK-GIV-Gαi ternary complexes are formed in living cells and that Gαi is transactivated within minutes after growth factor stimulation at the plasma membrane. Thus, GIV-derived biosensors provide a versatile strategy for visualizing, monitoring, and manipulating the dynamic association of Gαi with RTKs for noncanonical transactivation of G proteins in cells and illuminate a fundamental signaling event regulated by GIV during diverse cellular processes and pathophysiologic states.
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Affiliation(s)
| | | | | | | | | | | | - Pradipta Ghosh
- Departments of Medicine and Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093
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11
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Goupil E, Laporte SA, Hébert TE. A simple method to detect allostery in GPCR dimers. Methods Cell Biol 2014; 117:165-79. [PMID: 24143977 DOI: 10.1016/b978-0-12-408143-7.00009-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
G protein-coupled receptors (GPCRs) represent one of the largest families of cell surface receptors as key targets for pharmacological manipulation. G proteins have long been recognized as allosteric modulators of GPCR ligand binding. More recently, small molecule allosteric modulators have now been widely characterized for a number of GPCRs, and some are now used clinically. Many studies have also underscored the importance of GPCR dimerization or higher-order oligomerization in the control of the physiological responses they modulate. Thus, allosterism can also, between monomer equivalents in the context of a dimer, oligomer, or receptor mosaic, influence signaling pathways downstream. It therefore becomes essential to characterize both small molecule allosteric ligands and allosteric interactions between receptors modulated by canonical orthosteric ligands, in a pathway-specific manner. Here, we describe a simple, radioligand-binding method, which is designed to probe for allosteric modulation mediated by any GPCR interactor, from small molecules to interacting proteins. It can also detect allosteric asymmetries within a GPCR heterodimer, via orthosteric or allosteric ligands. This assay measures time-dependent ligand occupancy of radiolabeled orthosteric or (with adaptations) allosteric ligands as modulated by either small molecules or receptor dimer partners bound or unbound with their own ligands.
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Affiliation(s)
- Eugénie Goupil
- Department of Pharmacology, McGill University, Montréal, Québec, Canada
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12
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Palczewski K, Orban T. From atomic structures to neuronal functions of g protein-coupled receptors. Annu Rev Neurosci 2013; 36:139-64. [PMID: 23682660 DOI: 10.1146/annurev-neuro-062012-170313] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptors (GPCRs) are essential mediators of signal transduction, neurotransmission, ion channel regulation, and other cellular events. GPCRs are activated by diverse stimuli, including light, enzymatic processing of their N-termini, and binding of proteins, peptides, or small molecules such as neurotransmitters. GPCR dysfunction caused by receptor mutations and environmental challenges contributes to many neurological diseases. Moreover, modern genetic technology has helped identify a rich array of mono- and multigenic defects in humans and animal models that connect such receptor dysfunction with disease affecting neuronal function. The visual system is especially suited to investigate GPCR structure and function because advanced imaging techniques permit structural studies of photoreceptor neurons at both macro and molecular levels that, together with biochemical and physiological assessment in animal models, provide a more complete understanding of GPCR signaling.
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Affiliation(s)
- Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965, USA.
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13
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Kodama Y, Hu CD. Bimolecular fluorescence complementation (BiFC): a 5-year update and future perspectives. Biotechniques 2013; 53:285-98. [PMID: 23148879 DOI: 10.2144/000113943] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 09/28/2012] [Indexed: 11/23/2022] Open
Abstract
Over the past decade, bimolecular fluorescence complementation (BiFC) has emerged as a key technique to visualize protein-protein interactions in a variety of model organisms. The BiFC assay is based on reconstitution of an intact fluorescent protein when two complementary non-fluorescent fragments are brought together by a pair of interacting proteins. While the originally reported BiFC method has enabled the study of many protein-protein interactions, increasing demands to visualize protein-protein interactions under various physiological conditions have not only prompted a series of recent BiFC technology improvements, but also stimulated interest in developing completely new approaches. Here we review current BiFC technology, focusing on the development and improvement of BiFC systems, the understanding of split sites in fluorescent proteins, and enhancements in the signal-to-noise ratio. In addition, we provide perspectives on possible future improvements of the technique.
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Affiliation(s)
- Yutaka Kodama
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, Japan.
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14
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Ejendal KFK, Conley JM, Hu CD, Watts VJ. Bimolecular fluorescence complementation analysis of G protein-coupled receptor dimerization in living cells. Methods Enzymol 2013; 521:259-79. [PMID: 23351744 DOI: 10.1016/b978-0-12-391862-8.00014-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Emerging evidence indicates that G protein-coupled receptor (GPCR) signaling is mediated by receptor-receptor interactions at multiple levels. Thus, understanding the biochemistry and pharmacology of those receptor complexes is an important part of delineating the fundamental processes associated with GPCR-mediated signaling in human disease. A variety of experimental approaches have been used to explore these complexes, including bimolecular fluorescence complementation (BiFC) and multicolor BiFC (mBiFC). BiFC approaches have recently been used to explore the composition, cellular localization, and drug modulation of GPCR complexes. The basic methods for applying BiFC and mBiFC to study GPCRs in living cells are the subject of the present chapter.
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Affiliation(s)
- Karin F K Ejendal
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
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15
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Zhou J, Lin J, Zhou C, Deng X, Xia B. An improved bimolecular fluorescence complementation tool based on superfolder green fluorescent protein. Acta Biochim Biophys Sin (Shanghai) 2011; 43:239-44. [PMID: 21273204 DOI: 10.1093/abbs/gmq128] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Bimolecular fluorescence complementation (BiFC) has been widely used in the analysis of protein-protein interactions (PPIs) in recent years. There are many notable advantages of BiFC such as convenience and direct visualization of PPI in cells. However, BiFC has one common limitation: the separated non-fluorescent fragments can be spontaneously self-assembled into an intact protein, which leads to false-positive results. In this study, a pair of complementary fragments (sfGFPN and sfGFPC) was constructed by splitting superfolder GFP (sfGFP) between the 214 and 215 amino acid residue, and sfGFPC was mutated by site-directed gene mutagenesis to decrease the signal of negative control. Our results showed that mutations in sfGFPC (sfGFPC(m12)) can effectively decrease the signal of negative control. Thus, we provide an improved BiFC tool for the analysis of PPI. Further, since the self-assembly problem is a common shortcoming for application of BiFC, our research provides a feasible strategy for other BiFC candidate proteins with the same problem.
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Affiliation(s)
- Jun Zhou
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Biomedical Engineering, Beihang University, Beijing, China
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Vidi PA, Ejendal KF, Przybyla JA, Watts VJ. Fluorescent protein complementation assays: new tools to study G protein-coupled receptor oligomerization and GPCR-mediated signaling. Mol Cell Endocrinol 2011; 331:185-93. [PMID: 20654687 PMCID: PMC2990800 DOI: 10.1016/j.mce.2010.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 06/07/2010] [Accepted: 07/13/2010] [Indexed: 11/29/2022]
Abstract
G protein-coupled receptor (GPCR) signaling is mediated by protein-protein interactions at multiple levels. The characterization of the corresponding protein complexes is therefore paramount to the basic understanding of GPCR-mediated signal transduction. The number of documented interactions involving GPCRs is rapidly growing, and appreciating the functional significance of these complexes is clearly the next challenge. New experimental approaches including protein complementation assays (PCAs) have recently been used to examine the composition, plasma membrane targeting, and desensitization of protein complexes involved in GPCR signaling. These methods also hold promise for better understanding of drug-induced effects on GPCR interactions. This review focuses on the application of fluorescent PCAs for the study of GPCR signaling. Potential applications of PCAs in high-content screens are also presented. Non-fluorescent PCA techniques as well as combined assays for the detection of ternary and quaternary protein complexes are briefly discussed.
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Affiliation(s)
- Pierre-Alexandre Vidi
- Department of Basic Medical Sciences, School of Veterinary Medicine, Purdue University
| | - Karin F.K. Ejendal
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Purdue University
| | - Julie A. Przybyla
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Purdue University
| | - Val J. Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Purdue University
- Correspondence should be addressed to Dr. Val J. Watts, Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907-2051. Phone: (765) 496-3872, Fax: (765) 494-1414
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