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Helfinger L, Tate CG. Expression and Purification of the Human Thyroid-Stimulating Hormone Receptor. Methods Mol Biol 2022; 2507:313-325. [PMID: 35773589 DOI: 10.1007/978-1-0716-2368-8_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The thyroid-stimulating hormone receptor (TSHR) is a Class A G protein-coupled receptor (GPCR) that mediates signalling through the hypothalamic-pituitary-thyroid axis. Inappropriate activation of TSHR by autoantibodies or mutations, results in human disease such as Grave's disease and Hashimito's thyroiditis. Therefore, there is a need to develop novel therapeutics targeting the TSHR. Understanding the structure and mechanism of activation of this receptor would help elucidate the pathogenesis of disease and aid drug development. Here, we describe a method for the expression of the human TSHR in a mammalian cell line generated through a lentiviral expression system. The receptor is then purified by affinity chromatography in the ligand-free state and is suitable for structure determination by single-particle electron cryo-microscopy (cryo-EM).
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Jaramillo-Martinez V, Ganapathy V, Urbatsch IL. Peptide Tags and Domains for Expression and Detection of Mammalian Membrane Proteins at the Cell Surface. Methods Mol Biol 2022; 2507:337-358. [PMID: 35773591 DOI: 10.1007/978-1-0716-2368-8_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Normal functions of cell-surface proteins are dependent on their proper trafficking from the site of synthesis to the cell surface. Transport proteins mediating solute transfer across the plasma membrane constitute an important group of cell-surface proteins. There are several diseases resulting from mutations in these proteins that interfere with their transport function or trafficking, depending on the impact of the mutations on protein folding and structure. Recent advances in successful treatment of some of these diseases with small molecules which correct the mutations-induced folding and structural changes underline the need for detailed structural and biophysical characterization of membrane proteins. This requires methods to express and purify these proteins using heterologous expression systems. Here, using the solute carrier (SLC) transporter NaCT (Na+-coupled citrate transporter) as an example, we describe experimental strategies for this approach. We chose this example because several mutations in NaCT, distributed throughout the protein, cause a severe neurologic disease known as early infantile epileptic encephalopathy-25 (EIEE-25). NaCT was modified with various peptide tags, including a RGS-His10, a Twin-Strep, the SUMOstar domain, and an enhanced green fluorescent protein (EGFP), each alone or in various combinations. When transiently expressed in HEK293 cells, recombinant NaCT proteins underwent complex glycosylation, compartmentalized with the plasma membrane, and exhibited citrate transport activity similar to the nontagged protein. Surface NaCT expression was enhanced by the presence of SUMOstar on the N-terminus. The dual-purpose peptide epitopes RGS-His10 and Twin-Strep facilitated detection of NaCT by immunohistochemistry and western blot and may serve useful tags for affinity purification. This approach sets the stage for future analyses of mutant NaCT proteins that may alter protein folding and trafficking. It also demonstrates the capability of a transient mammalian cell expression system to produce human NaCT of sufficient quality and quantity to augment future biophysical and structural studies and drug discovery efforts.
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Affiliation(s)
- Valeria Jaramillo-Martinez
- Departments of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Vadivel Ganapathy
- Cell Biology and Biochemistry, and the Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Ina L Urbatsch
- Cell Biology and Biochemistry, and the Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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Yeliseev A, van den Berg A, Zoubak L, Hines K, Stepnowski S, Williston K, Yan W, Gawrisch K, Zmuda J. Thermostability of a recombinant G protein-coupled receptor expressed at high level in mammalian cell culture. Sci Rep 2020; 10:16805. [PMID: 33033368 PMCID: PMC7546613 DOI: 10.1038/s41598-020-73813-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/15/2020] [Indexed: 12/13/2022] Open
Abstract
Rational design of pharmaceutical drugs targeting integral membrane G protein-coupled receptors (GPCR) requires thorough understanding of ligand binding and mechanism of activation through high resolution structural studies of purified proteins. Due to inherent conformational flexibility of GPCR, stabilization of these proteins solubilized from cell membranes into detergents is a challenging task. Here, we take advantage of naturally occurring post-translational modifications for stabilization of purified GPCR in detergent micelles. The recombinant cannabinoid CB2 receptor was expressed at high yield in Expi293F mammalian cell cultures, solubilized and purified in Façade detergent. We report superior stability of the mammalian cell-expressed receptor compared to its E.coli-expressed counterpart, due to contributions from glycosylation of the N terminus and palmitoylation of the C terminus of CB2. Finally, we demonstrate that the mammalian Expi293F amino acid labelling kit is suitable for preparation of multi-milligram quantities of high quality, selectively stable isotope-labeled GPCR for studies by nuclear magnetic resonance.
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Affiliation(s)
- Alexei Yeliseev
- National Institute on Alcoholism and Alcohol Abuse, NIH, Bethesda, MD, 20892, USA.
| | | | - Lioudmila Zoubak
- National Institute on Alcoholism and Alcohol Abuse, NIH, Bethesda, MD, 20892, USA
| | - Kirk Hines
- National Institute on Alcoholism and Alcohol Abuse, NIH, Bethesda, MD, 20892, USA
| | - Sam Stepnowski
- ThermoFisher Scientific, 7335 Executive Way, Frederick, MD, 21704, USA
| | - Kyle Williston
- ThermoFisher Scientific, 7335 Executive Way, Frederick, MD, 21704, USA
| | - Wanhua Yan
- ThermoFisher Scientific, 7335 Executive Way, Frederick, MD, 21704, USA
| | - Klaus Gawrisch
- National Institute on Alcoholism and Alcohol Abuse, NIH, Bethesda, MD, 20892, USA
| | - Jonathan Zmuda
- ThermoFisher Scientific, 7335 Executive Way, Frederick, MD, 21704, USA
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Generating therapeutic monoclonal antibodies to complex multi-spanning membrane targets: Overcoming the antigen challenge and enabling discovery strategies. Methods 2020; 180:111-126. [PMID: 32422249 DOI: 10.1016/j.ymeth.2020.05.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/21/2020] [Accepted: 05/13/2020] [Indexed: 12/17/2022] Open
Abstract
Complex integral membrane proteins, which are embedded in the cell surface lipid bilayer by multiple transmembrane spanning helices, encompass families of proteins which are important target classes for drug discovery. These protein families include G protein-coupled receptors, ion channels and transporters. Although these proteins have typically been targeted by small molecule drugs and peptides, the high specificity of monoclonal antibodies offers a significant opportunity to selectively modulate these target proteins. However, it remains the case that isolation of antibodies with desired pharmacological function(s) has proven difficult due to technical challenges in preparing membrane protein antigens suitable to support antibody drug discovery. In this review recent progress in defining strategies for generation of membrane protein antigens is outlined. We also highlight antibody isolation strategies which have generated antibodies which bind the membrane protein and modulate the protein function.
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Miljus T, Sykes DA, Harwood CR, Vuckovic Z, Veprintsev DB. GPCR Solubilization and Quality Control. Methods Mol Biol 2020; 2127:105-127. [PMID: 32112318 DOI: 10.1007/978-1-0716-0373-4_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
G protein-coupled receptors (GPCRs) are versatile membrane proteins involved in the regulation of many physiological processes and pathological conditions, making them interesting pharmacological targets. In order to study their structure and function, GPCRs are traditionally extracted from membranes using detergents. However, due to their hydrophobic nature, intrinsic instability in aqueous solutions, and their denaturing effects, the isolation of properly folded and functional GPCRs is not trivial. Therefore, it is of crucial importance to solubilize receptors under mild conditions and control the sample quality subsequently. Here we describe widely used methods for small-scale GPCR solubilization, followed by quality control based on fluorescence size-exclusion chromatography, SDS-PAGE, temperature-induced protein unfolding (CPM dye binding) and fluorescent ligand binding assay. These methods can easily be used to assess the thermostability and functionality of a GPCR sample exposed to different conditions, such as the use of various detergents, addition of lipids and ligands, making them valuable for obtaining an optimal sample quality for structural and functional studies.
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Affiliation(s)
- Tamara Miljus
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Biology, ETH Zürich, Zürich, Switzerland
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - David A Sykes
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
- Division of Physiology, Pharmacology & Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Clare R Harwood
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
- Division of Physiology, Pharmacology & Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Ziva Vuckovic
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Biology, ETH Zürich, Zürich, Switzerland
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Dmitry B Veprintsev
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen PSI, Switzerland.
- Department of Biology, ETH Zürich, Zürich, Switzerland.
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK.
- Division of Physiology, Pharmacology & Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.
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Therapeutic Monoclonal Antibodies to Complex Membrane Protein Targets: Antigen Generation and Antibody Discovery Strategies. BioDrugs 2019; 32:339-355. [PMID: 29934752 DOI: 10.1007/s40259-018-0289-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cell surface membrane proteins comprise a wide array of structurally and functionally diverse proteins involved in a variety of important physiological and homeostatic processes. Complex integral membrane proteins, which are embedded in the lipid bilayer by multiple transmembrane-spanning helices, are represented by families of proteins that are important target classes for drug discovery. Such protein families include G-protein-coupled receptors, ion channels and transporters. Although these targets have typically been the domain of small-molecule drugs, the exquisite specificity of monoclonal antibodies offers a significant opportunity to selectively modulate these target proteins. Nevertheless, the isolation of antibodies with desired pharmacological functions has proved difficult because of technical challenges in preparing membrane protein antigens for antibody drug discovery. In this review, we describe recent progress in defining strategies for the generation of membrane protein antigens. We also describe antibody-isolation strategies that identify antibodies that bind the membrane protein and modulate protein function.
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7
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Behrens M, Briand L, de March CA, Matsunami H, Yamashita A, Meyerhof W, Weyand S. Structure-Function Relationships of Olfactory and Taste Receptors. Chem Senses 2019; 43:81-87. [PMID: 29342245 DOI: 10.1093/chemse/bjx083] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The field of chemical senses has made major progress in understanding the cellular mechanisms of olfaction and taste in the past 2 decades. However, the molecular understanding of odor and taste recognition is still lagging far behind and will require solving multiple structures of the relevant full-length receptors in complex with native ligands to achieve this goal. However, the development of multiple complimentary strategies for the structure determination of G protein-coupled receptors (GPCRs) makes this goal realistic. The common conundrum of how multi-specific receptors that recognize a large number of different ligands results in a sensory perception in the brain will only be fully understood by a combination of high-resolution receptor structures and functional studies. This review discusses the first steps on this pathway, including biochemical and physiological assays, forward genetics approaches, molecular modeling, and the first steps towards the structural biology of olfactory and taste receptors.
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Affiliation(s)
- Maik Behrens
- Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Germany
| | - Loïc Briand
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRA, Univ. de Bourgogne- Franche-Comté, France
| | - Claire A de March
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, USA
| | - Atsuko Yamashita
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan
| | - Wolfgang Meyerhof
- Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Germany
| | - Simone Weyand
- Department of Biochemistry, University of Cambridge, UK
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Elegheert J, Behiels E, Bishop B, Scott S, Woolley RE, Griffiths SC, Byrne EFX, Chang VT, Stuart DI, Jones EY, Siebold C, Aricescu AR. Lentiviral transduction of mammalian cells for fast, scalable and high-level production of soluble and membrane proteins. Nat Protoc 2018; 13:2991-3017. [PMID: 30455477 PMCID: PMC6364805 DOI: 10.1038/s41596-018-0075-9] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Structural, biochemical and biophysical studies of eukaryotic soluble and membrane proteins require their production in milligram quantities. Although large-scale protein expression strategies based on transient or stable transfection of mammalian cells are well established, they are associated with high consumable costs, limited transfection efficiency or long and tedious selection of clonal cell lines. Lentiviral transduction is an efficient method for the delivery of transgenes to mammalian cells and unifies the ease of use and speed of transient transfection with the robust expression of stable cell lines. In this protocol, we describe the design and step-by-step application of a lentiviral plasmid suite, termed pHR-CMV-TetO2, for the constitutive or inducible large-scale production of soluble and membrane proteins in HEK293 cell lines. Optional features include bicistronic co-expression of fluorescent marker proteins for enrichment of co-transduced cells using cell sorting and of biotin ligase for in vivo biotinylation. We demonstrate the efficacy of the method for a set of soluble proteins and for the G-protein-coupled receptor (GPCR) Smoothened (SMO). We further compare this method with baculovirus transduction of mammalian cells (BacMam), using the type-A γ-aminobutyric acid receptor (GABAAR) β3 homopentamer as a test case. The protocols described here are optimized for simplicity, speed and affordability; lead to a stable polyclonal cell line and milligram-scale amounts of protein in 3-4 weeks; and routinely achieve an approximately three- to tenfold improvement in protein production yield per cell as compared to transient transduction or transfection.
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Affiliation(s)
- Jonathan Elegheert
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Bordeaux, France.
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France.
| | - Ester Behiels
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Benjamin Bishop
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Suzanne Scott
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Rachel E Woolley
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Samuel C Griffiths
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Eamon F X Byrne
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Veronica T Chang
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - David I Stuart
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - A Radu Aricescu
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
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