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Noh S, Tombola F, Burke P. Nanowire biosensors with olfactory proteins: towards a genuine electronic nose with single molecule sensitivity and high selectivity. NANOTECHNOLOGY 2023; 34:465502. [PMID: 37524056 DOI: 10.1088/1361-6528/acebf3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 07/31/2023] [Indexed: 08/02/2023]
Abstract
We describe the concept and roadmap of an engineered electronic nose with specificity towards analytes that differ by as little as one carbon atom, and sensitivity of being able to electrically register a single molecule of analyte. The analyte could be anything that natural noses can detect, e.g. trinitrotoluene (TNT), cocaine, aromatics, volatile organic compounds etc. The strategy envisioned is to genetically engineer a fused olfactory odorant receptor (odorant receptor (OR), a membrane-bound G-protein coupled receptor (GPCR) with high selectivity) to an ion channel protein, which opens in response to binding of the ligand to the OR. The lipid bilayer supporting the fused sensing protein would be intimately attached to a nanowire or nanotube network (either via a covalent tether or a non-covalent physisorption process), which would electrically detect the opening of the ion channel, and hence the binding of a single ligand to a single OR protein domain. Three man-made technological advances: (1) fused GPCR to ion channel protein, (2) nanowire sensing of single ion channel activity, and (3) lipid bilayer to nanotube/nanowire tethering chemistry and on natural technology (sensitivity and selectivity of OR domains to specific analytes) each have been demonstrated and/or studied independently. The combination of these three technological advances and the result of millions of years of evolution of OR proteins would enable the goal of single molecule sensing with specificity towards analytes that differ by as little as one carbon atom. This is both a review of the past and a vision of the future.
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Affiliation(s)
- Sangjun Noh
- EECS, UC Irvine, Irvine, CA, United States of America
| | - Francesco Tombola
- Dept. of Physiology and Biophysics, UC Irvine, Irvine, CA, United States of America
| | - Peter Burke
- EECS, UC Irvine, Irvine, CA, United States of America
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García-Fernández MD, Chatelain FC, Nury H, Moroni A, Moreau CJ. Distinct classes of potassium channels fused to GPCRs as electrical signaling biosensors. CELL REPORTS METHODS 2021; 1:None. [PMID: 34977850 PMCID: PMC8688152 DOI: 10.1016/j.crmeth.2021.100119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/05/2021] [Accepted: 10/26/2021] [Indexed: 11/23/2022]
Abstract
Ligand-gated ion channels (LGICs) are natural biosensors generating electrical signals in response to the binding of specific ligands. Creating de novo LGICs for biosensing applications is technically challenging. We have previously designed modified LGICs by linking G protein-coupled receptors (GPCRs) to the Kir6.2 channel. In this article, we extrapolate these design concepts to other channels with different structures and oligomeric states, namely a tetrameric viral Kcv channel and the dimeric mouse TREK-1 channel. After precise engineering of the linker regions, the two ion channels were successfully regulated by a GPCR fused to their N-terminal domain. Two-electrode voltage-clamp recordings showed that Kcv and mTREK-1 fusions were inhibited and activated by GPCR agonists, respectively, and antagonists abolished both effects. Thus, dissimilar ion channels can be allosterically regulated through their N-terminal domains, suggesting that this is a generalizable approach for ion channel engineering.
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Affiliation(s)
| | - Franck C. Chatelain
- Université Côte d’Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles, 06650 Valbonne, France
| | - Hugues Nury
- Université Grenoble Alpes, CNRS, CEA, IBS, 71, av. Martyrs, CS10090, 38044 Grenoble Cedex9, France
| | - Anna Moroni
- University of Milan, Department of Biosciences, Via Celoria 26, 20133 Milano, Italy
| | - Christophe J. Moreau
- Université Grenoble Alpes, CNRS, CEA, IBS, 71, av. Martyrs, CS10090, 38044 Grenoble Cedex9, France
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3
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Vanuytsel S, Carniello J, Wallace MI. Artificial Signal Transduction across Membranes. Chembiochem 2019; 20:2569-2580. [DOI: 10.1002/cbic.201900254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/09/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Steven Vanuytsel
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
| | - Joanne Carniello
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
| | - Mark Ian Wallace
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
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Tuning the allosteric regulation of artificial muscarinic and dopaminergic ligand-gated potassium channels by protein engineering of G protein-coupled receptors. Sci Rep 2017; 7:41154. [PMID: 28145461 PMCID: PMC5286527 DOI: 10.1038/srep41154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/14/2016] [Indexed: 12/15/2022] Open
Abstract
Ligand-gated ion channels enable intercellular transmission of action potential through synapses by transducing biochemical messengers into electrical signal. We designed artificial ligand-gated ion channels by coupling G protein-coupled receptors to the Kir6.2 potassium channel. These artificial channels called ion channel-coupled receptors offer complementary properties to natural channels by extending the repertoire of ligands to those recognized by the fused receptors, by generating more sustained signals and by conferring potassium selectivity. The first artificial channels based on the muscarinic M2 and the dopaminergic D2L receptors were opened and closed by acetylcholine and dopamine, respectively. We find here that this opposite regulation of the gating is linked to the length of the receptor C-termini, and that C-terminus engineering can precisely control the extent and direction of ligand gating. These findings establish the design rules to produce customized ligand-gated channels for synthetic biology applications.
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Ion Channels as Reporters of Membrane Receptor Function: Automated Analysis in Xenopus Oocytes. Methods Mol Biol 2017; 1635:283-301. [PMID: 28755375 DOI: 10.1007/978-1-4939-7151-0_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
G-protein-coupled receptors (GPCR) are the most widely used system of communication used by cells. They sense external signals and translate them into intracellular signals. The information is carried mechanically across the cell membrane, without perturbing its integrity. Agonist binding on the extracellular side causes a change in receptor conformation which propagates to the intracellular side and causes release of activated G-proteins, the first messengers of a variety of signaling cascades.Permitting access to powerful electrophysiological techniques, ion channels can be employed to monitor precisely the most proximal steps of GPCR signaling, receptor conformational changes, and G-protein release. The former is achieved by physical attachment of a potassium channel to the GPCR to create an Ion-Channel Coupled Receptor (ICCR). The latter is based on the use of G-protein-regulated potassium channels (GIRK). We describe here how these two systems may be used in the Xenopus oocyte heterologous system with a robotic system for increased throughput.
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Coupling of olfactory receptor and ion channel for rapid and sensitive visualization of odorant response. Acta Biomater 2015; 22:1-7. [PMID: 25931017 DOI: 10.1016/j.actbio.2015.04.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 03/31/2015] [Accepted: 04/22/2015] [Indexed: 11/23/2022]
Abstract
In the human smell sensing system, there are about 390 kinds of olfactory receptors (ORs) which bind to various odorants with different affinities and specificities. Characterization and odorant binding pattern analysis of the ORs are essential for understanding of human olfaction and to mimic the olfactory system in various applications. Although various cell-based odorant screening systems have been developed for this purpose, many human ORs (hORs) still remain orphan because of the time-consuming and labor-intensive experimental procedures of the available screening methods. In this study, we constructed an ion channel-coupled hOR for simple odorant detection by rapidly visualizing the odorant response to overcome the limitations of conventional screening systems. The hORs were coupled to the Kir6.2 potassium channel and the fusion proteins were expressed in HEK293 cells. In this system, when an odorant binds to the hORs coupled to the ion channel, a conformational change in the OR occurs, which consequently opens the ion channel to result in ion influx into the cell. This ion influx was then visualized using a membrane potential dye. Cells expressing ion channel-coupled hORs showed high sensitivity and selectivity to their specific odorants, and the odorant-hOR binding pattern was visualized to identify the response of individual hORs to various odorants, as well as the response of various hORs to various odorants. These results indicate that the ion channel-coupled hOR system can be effectively used not only for simple and fast high-throughput odorant screening, but also to visualize the odorant-hOR response pattern.
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Abstract
Ion channel-coupled receptor (ICCR) is a recent technology based on the fusion of G protein-coupled receptors (GPCRs) to an ion channel. Binding of ligands on the GPCR triggers conformational changes of the receptor that are mechanically transmitted to the ion channel gates, generating an electrical signal easily detectable with conventional electrophysiological techniques. ICCRs are heterologously expressed in Xenopus oocytes and offers several advantages such as: (i) real-time recordings on single cells, (ii) standard laboratory environment and inexpensive media for Xenopus oocytes maintenance, (iii) absence of protein purification steps, (iv) sensitivity to agonists and antagonists in concentration-dependent manner, (v) compatibility with a Gi/o protein activation assay based on Kir3.x channels, and (vi) ability to detect receptor activation independently of intracellular effectors. This last characteristic of ICCRs led to the development of a functional assay for G protein-"uncoupled" receptors such as GPCRs optimized for crystallization by alteration of their third intracellular (i3) loop. One of the most widely used approaches consists in replacing the i3 loop with the T4 phage lysozyme (T4L) domain that obstructs the access of G proteins to their binding site. We recently demonstrated that the ICCR technology can functionally characterize GPCRs(T4L). Two-electrode voltage-clamp (TEVC) recordings revealed that apparent affinities and sensitivities to ligands are not affected by T4L insertion, while ICCRs(T4L) displayed a partial agonist phenotype upon binding of full agonists, suggesting that ICCRs could detect intermediate-active states. This chapter aims to provide exhaustive details from molecular biology steps to electrophysiological recordings for the design and the characterization of ICCRs and ICCRs(T4L).
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Lim JH, Oh EH, Park J, Hong S, Park TH. Ion-channel-coupled receptor-based platform for a real-time measurement of G-protein-coupled receptor activities. ACS NANO 2015; 9:1699-1706. [PMID: 25625737 DOI: 10.1021/nn506494e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A simple but efficient measurement platform based on ion-channel-coupled receptors and nanovesicles was developed for monitoring the real-time activity of G-protein-coupled receptors (GPCRs). In this work, an olfactory receptor (OR), the most common class A GPCR, was covalently fused with a Kir6.2 channel so that the GPCR action directly induced the opening of the ion channels and changes in the electrical membrane potential without complex cellular signaling processes. This strategy reduced the measurement errors caused by instability of various cellular components. In addition, rather than using whole cells, a cell-surface-derived nanovesicle was used to preserve the membrane-integrated structure of GPCRs and to exclude case-dependent cellular conditions. Another merit of using the nanovesicle is that nanovesicles can be easily combined with nanomaterial-based field-effect transistors (FETs) to build a sensitive and stable measurement platform to monitor GPCR activities with high sensitivity in real-time. Using a platform based on carbon nanotube FETs and nanovesicles carrying Kir6.2-channel-coupled ORs, we monitored the real-time response of ORs to their ligand molecules. Significantly, since this platform does not rely on rather unstable cell signaling pathways, our platform could be utilized for a rather long time period without losing its functionality. This system can be utilized extensively for simple and sensitive analysis of the activities of various GPCRs and should enable various academic and practical applications.
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Affiliation(s)
- Jong Hyun Lim
- School of Chemical and Biological Engineering, ‡Interdisciplinary Program for Bioengineering, §Department of Physics and Astronomy, and ⊥Department of Biophysics and Chemical Biology, Seoul National University , Seoul 151-744, Republic of Korea
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Sapay N, Estrada-Mondragon A, Moreau C, Vivaudou M, Crouzy S. Rebuilding a macromolecular membrane complex at the atomic scale: case of the Kir6.2 potassium channel coupled to the muscarinic acetylcholine receptor M2. Proteins 2014; 82:1694-707. [PMID: 24464835 DOI: 10.1002/prot.24521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/02/2013] [Accepted: 01/16/2014] [Indexed: 12/29/2022]
Abstract
Ion channel-coupled receptors (ICCR) are artificial proteins built from a G protein-coupled receptor and an ion channel. Their use as molecular biosensors is promising in diagnosis and high-throughput drug screening. The concept of ICCR was initially validated with the combination of the muscarinic receptor M2 with the inwardly rectifying potassium channel Kir6.2. A long protein engineering phase has led to the biochemical characterization of the M2-Kir6.2 construct. However, its molecular mechanism remains to be elucidated. In particular, it is important to determine how the activation of M2 by its agonist acetylcholine triggers the modulation of the Kir6.2 channel via the M2-Kir6.2 linkage. In the present study, we have developed and validated a computational approach to rebuild models of the M2-Kir6.2 chimera from the molecular structure of M2 and Kir6.2. The protocol was first validated on the known protein complexes of the μ-opioid Receptor, the CXCR4 receptor and the Kv1.2 potassium channel. When applied to M2-Kir6.2, our protocol produced two possible models corresponding to two different orientations of M2. Both models highlights the role of the M2 helices I and VIII in the interaction with Kir6.2, as well as the role of the Kir6.2 N-terminus in the channel opening. Those two hypotheses will be explored in a future experimental study of the M2-Kir6.2 construct.
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Affiliation(s)
- Nicolas Sapay
- Laboratoire de Chimie et Biologie des Métaux, Institut de Recherche en Technologie et Sciences pour le Vivant, CEA iRTSV/LCBM/GMCT, CNRS UMR 5249, Université Grenoble Alpes, F-38054, Grenoble Cedex 9, France
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Niescierowicz K, Caro L, Cherezov V, Vivaudou M, Moreau CJ. Functional assay for T4 lysozyme-engineered G protein-coupled receptors with an ion channel reporter. Structure 2013; 22:149-55. [PMID: 24268646 DOI: 10.1016/j.str.2013.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 09/24/2013] [Accepted: 10/07/2013] [Indexed: 01/06/2023]
Abstract
Structural studies of G protein-coupled receptors (GPCRs) extensively use the insertion of globular soluble protein domains to facilitate their crystallization. However, when inserted in the third intracellular loop (i3 loop), the soluble protein domain disrupts their coupling to G proteins and impedes the GPCRs functional characterization by standard G protein-based assays. Therefore, activity tests of crystallization-optimized GPCRs are essentially limited to their ligand binding properties using radioligand binding assays. Functional characterization of additional thermostabilizing mutations requires the insertion of similar mutations in the wild-type receptor to allow G protein-activation tests. We demonstrate that ion channel-coupled receptor technology is a complementary approach for a comprehensive functional characterization of crystallization-optimized GPCRs and potentially of any engineered GPCR. Ligand-induced conformational changes of the GPCRs are translated into electrical signal and detected by simple current recordings, even though binding of G proteins is sterically blocked by the added soluble protein domain.
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Affiliation(s)
- Katarzyna Niescierowicz
- University Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France; Le Centre National de la Recherche Scientifique (CNRS), IBS, LabEx ICST, F-38027 Grenoble, France; Direction des Sciences du Vivant du Comissariat à l'Energie Atomique (CEA), F-38027 Grenoble, France
| | - Lydia Caro
- University Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France; Le Centre National de la Recherche Scientifique (CNRS), IBS, LabEx ICST, F-38027 Grenoble, France; Direction des Sciences du Vivant du Comissariat à l'Energie Atomique (CEA), F-38027 Grenoble, France
| | - Vadim Cherezov
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michel Vivaudou
- University Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France; Le Centre National de la Recherche Scientifique (CNRS), IBS, LabEx ICST, F-38027 Grenoble, France; Direction des Sciences du Vivant du Comissariat à l'Energie Atomique (CEA), F-38027 Grenoble, France
| | - Christophe J Moreau
- University Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France; Le Centre National de la Recherche Scientifique (CNRS), IBS, LabEx ICST, F-38027 Grenoble, France; Direction des Sciences du Vivant du Comissariat à l'Energie Atomique (CEA), F-38027 Grenoble, France.
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Baker CA, Bright LK, Aspinwall CA. Photolithographic fabrication of microapertures with well-defined, three-dimensional geometries for suspended lipid membrane studies. Anal Chem 2013; 85:9078-86. [PMID: 23987300 DOI: 10.1021/ac401639n] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Robust and high-density biosensors incorporating suspended lipid membranes require microfabricated apertures that can be readily integrated into complex analysis systems. Apertures with well-defined, three-dimensional geometries enable the formation of suspended lipid membranes and facilitate reduced aperture size compared to vertical-walled apertures. Unfortunately, existing methods of producing apertures with well-defined, three-dimensional geometries are based on complex and expensive fabrication procedures, some of which yield apertures in excessively fragile thin-film materials. Here, we describe a microfabrication method utilizing incline and rotate lithography that achieves sloped-wall microapertures in SU-8 polymer substrates with precision control of the aperture diameter, substrate thickness, and wall angle. This approach is simple, is of low cost, and is readily scaled up to allow highly reproducible parallel fabrication. The effect of the incident angle of UV exposure and the size of photomask features on the aperture geometry were investigated, yielding aperture diameters as small as 7 μm and aperture wall angles ranging from 8° to 36° measured from the normal axis. Black lipid membranes were suspended across the apertures and showed normalized conductance values of 0.02-0.05 pS μm(-2) and breakdown voltages of 400-600 mV. The functionality of the resulting sloped-wall microapertures was validated via measurement of reconstituted α-hemolysin activity and the voltage-gated channel activity of alamethicin.
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Affiliation(s)
- Christopher A Baker
- Department of Chemistry and Biochemistry, University of Arizona , 1306 East University Boulevard, Tucson, Arizona 85721, United States
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Bai Q, Zhang Y, Ban Y, Liu H, Yao X. Computational study on the different ligands induced conformation change of β2 adrenergic receptor-Gs protein complex. PLoS One 2013; 8:e68138. [PMID: 23922653 PMCID: PMC3726664 DOI: 10.1371/journal.pone.0068138] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/24/2013] [Indexed: 01/23/2023] Open
Abstract
β2 adrenergic receptor (β2AR) regulated many key physiological processes by activation of a heterotrimeric GTP binding protein (Gs protein). This process could be modulated by different types of ligands. But the details about this modulation process were still not depicted. Here, we performed molecular dynamics (MD) simulations on the structures of β2AR-Gs protein in complex with different types of ligands. The simulation results demonstrated that the agonist BI-167107 could form hydrogen bonds with Ser2035.42, Ser2075.46 and Asn2936.55 more than the inverse agonist ICI 118,551. The different binding modes of ligands further affected the conformation of β2AR. The energy landscape profiled the energy contour map of the stable and dissociated conformation of Gαs and Gβγ when different types of ligands bound to β2AR. It also showed the minimum energy pathway about the conformational change of Gαs and Gβγ along the reaction coordinates. By using interactive essential dynamics analysis, we found that Gαs and Gβγ domain of Gs protein had the tendency to separate when the inverse agonist ICI 118,551 bound to β2AR. The α5-helix had a relatively quick movement with respect to transmembrane segments of β2AR when the inverse agonist ICI 118,551 bound to β2AR. Besides, the analysis of the centroid distance of Gαs and Gβγ showed that the Gαs was separated from Gβγ during the MD simulations. Our results not only could provide details about the different types of ligands that induced conformational change of β2AR and Gs protein, but also supplied more information for different efficacies of drug design of β2AR.
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Affiliation(s)
- Qifeng Bai
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
| | - Yang Zhang
- School of Information Science and Engineering, Lanzhou University, Lanzhou, China
| | - Yihe Ban
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
| | - Huanxiang Liu
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Xiaojun Yao
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
- Key Lab of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, Lanzhou, China
- * E-mail:
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Caro LN, Moreau CJ, Estrada-Mondragón A, Ernst OP, Vivaudou M. Engineering of an artificial light-modulated potassium channel. PLoS One 2012; 7:e43766. [PMID: 22928030 PMCID: PMC3425490 DOI: 10.1371/journal.pone.0043766] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 07/24/2012] [Indexed: 12/13/2022] Open
Abstract
Ion Channel-Coupled Receptors (ICCRs) are artificial receptor-channel fusion proteins designed to couple ligand binding to channel gating. We previously validated the ICCR concept with various G protein-coupled receptors (GPCRs) fused with the inward rectifying potassium channel Kir6.2. Here we characterize a novel ICCR, consisting of the light activated GPCR, opsin/rhodopsin, fused with Kir6.2. To validate our two-electrode voltage clamp (TEVC) assay for activation of the GPCR, we first co-expressed the apoprotein opsin and the G protein-activated potassium channel Kir3.1F137S (Kir3.1*) in Xenopus oocytes. Opsin can be converted to rhodopsin by incubation with 11-cis retinal and activated by light-induced retinal cis→trans isomerization. Alternatively opsin can be activated by incubation of oocytes with all-trans-retinal. We found that illumination of 11-cis-retinal-incubated oocytes co-expressing opsin and Kir3.1* caused an immediate and long-lasting channel opening. In the absence of 11-cis retinal, all-trans-retinal also opened the channel persistently, although with slower kinetics. We then used the oocyte/TEVC system to test fusion proteins between opsin/rhodopsin and Kir6.2. We demonstrate that a construct with a C-terminally truncated rhodopsin responds to light stimulus independent of G protein. By extending the concept of ICCRs to the light-activatable GPCR rhodopsin we broaden the potential applications of this set of tools.
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Affiliation(s)
- Lydia N. Caro
- CNRS, Institut de Biologie Structurale, Grenoble, France
- CEA, Institut de Biologie Structurale, LabEx ICST, Grenoble, France
- Université Grenoble I, Institut de Biologie Structurale, Grenoble, France
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Christophe J. Moreau
- CNRS, Institut de Biologie Structurale, Grenoble, France
- CEA, Institut de Biologie Structurale, LabEx ICST, Grenoble, France
- Université Grenoble I, Institut de Biologie Structurale, Grenoble, France
| | - Argel Estrada-Mondragón
- CNRS, Institut de Biologie Structurale, Grenoble, France
- CEA, Institut de Biologie Structurale, LabEx ICST, Grenoble, France
- Université Grenoble I, Institut de Biologie Structurale, Grenoble, France
| | - Oliver P. Ernst
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Michel Vivaudou
- CNRS, Institut de Biologie Structurale, Grenoble, France
- CEA, Institut de Biologie Structurale, LabEx ICST, Grenoble, France
- Université Grenoble I, Institut de Biologie Structurale, Grenoble, France
- * E-mail:
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