1
|
Caron NS, Aly AEE, Findlay Black H, Martin DDO, Schmidt ME, Ko S, Anderson C, Harvey EM, Casal LL, Anderson LM, Rahavi SMR, Reid GSD, Oda MN, Stanimirovic D, Abulrob A, McBride JL, Leavitt BR, Hayden MR. Systemic delivery of mutant huntingtin lowering antisense oligonucleotides to the brain using apolipoprotein A-I nanodisks for Huntington disease. J Control Release 2024; 367:27-44. [PMID: 38215984 DOI: 10.1016/j.jconrel.2024.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 12/09/2023] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
Efficient delivery of therapeutics to the central nervous system (CNS) remains a major challenge for the treatment of neurological diseases. Huntington disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide expansion mutation in the HTT gene which codes for a toxic mutant huntingtin (mHTT) protein. Pharmacological reduction of mHTT in the CNS using antisense oligonucleotides (ASO) ameliorates HD-like phenotypes in rodent models of HD, with such therapies being investigated in clinical trials for HD. In this study, we report the optimization of apolipoprotein A-I nanodisks (apoA-I NDs) as vehicles for delivery of a HTT-targeted ASO (HTT ASO) to the brain and peripheral organs for HD. We demonstrate that apoA-I wild type (WT) and the apoA-I K133C mutant incubated with a synthetic lipid, 1,2-dimyristoyl-sn-glycero-3-phosphocholine, can self-assemble into monodisperse discoidal particles with diameters <20 nm that transmigrate across an in vitro blood-brain barrier model of HD. We demonstrate that apoA-I NDs are well tolerated in vivo, and that apoA-I K133C NDs show enhanced distribution to the CNS and peripheral organs compared to apoA-I WT NDs following systemic administration. ApoA-I K133C conjugated with HTT ASO forms NDs (HTT ASO NDs) that induce significant mHTT lowering in the liver, skeletal muscle and heart as well as in the brain when delivered intravenously in the BACHD mouse model of HD. Furthermore, HTT ASO NDs increase the magnitude of mHTT lowering in the striatum and cortex compared to HTT ASO alone following intracerebroventricular administration. These findings demonstrate the potential utility of apoA-I NDs as biocompatible vehicles for enhancing delivery of mutant HTT lowering ASOs to the CNS and peripheral organs for HD.
Collapse
Affiliation(s)
- Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amirah E-E Aly
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hailey Findlay Black
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dale D O Martin
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada; Department of Biology, University of Waterloo, Ontario, Canada
| | - Mandi E Schmidt
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Seunghyun Ko
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Christine Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Emily M Harvey
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Lorenzo L Casal
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Lisa M Anderson
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada
| | - Seyed M R Rahavi
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gregor S D Reid
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Danica Stanimirovic
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Abedelnasser Abulrob
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, Ontario, Canada
| | - Jodi L McBride
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA; Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
| |
Collapse
|
2
|
Elbahnasawy MA, Nasr ML. DNA-nanostructure-templated assembly of planar and curved lipid-bilayer membranes. Front Chem 2023; 10:1047874. [PMID: 36844038 PMCID: PMC9944057 DOI: 10.3389/fchem.2022.1047874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/21/2022] [Indexed: 02/10/2023] Open
Abstract
Lipid-bilayer nanodiscs and liposomes have been developed to stabilize membrane proteins in order to study their structures and functions. Nanodiscs are detergent-free, water-soluble, and size-controlled planar phospholipid-bilayer platforms. On the other hand, liposomes are curved phospholipid-bilayer spheres with an aqueous core used as drug delivery systems and model membrane platforms for studying cellular activities. A long-standing challenge is the generation of a homogenous and monodispersed lipid-bilayer system with a very wide range of dimensions and curvatures (elongation, bending, and twisting). A DNA-origami template provides a way to control the shapes, sizes, and arrangements of lipid bilayers via enforcing the assembly of lipid bilayers within the cavities created by DNA nanostructures. Here, we provide a concise overview and discuss how to design planar and curved lipid-bilayer membranes by using DNA-origami nanostructures as templates. Finally, we will discuss the potential applications of DNA-origami nanostructures in the structural and functional studies of large membrane proteins and their complexes.
Collapse
Affiliation(s)
- Mostafa A. Elbahnasawy
- Immunology Laboratory, Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo, Egypt
| | - Mahmoud L. Nasr
- Renal Division and Engineering in Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States,*Correspondence: Mahmoud L. Nasr,
| |
Collapse
|
3
|
Screening and characterization of inhibitory vNAR targeting nanodisc-assembled influenza M2 proteins. iScience 2022; 26:105736. [PMID: 36570769 PMCID: PMC9771723 DOI: 10.1016/j.isci.2022.105736] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 10/16/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Influenza A virus poses a constant challenge to human health. The highly conserved influenza matrix-2 (M2) protein is an attractive target for the development of a universal antibody-based drug. However, screening using antigens with subphysiological conformation in a nonmembrane environment significantly reduces the generation of efficient antibodies. Here, M2(1-46) was incorporated into nanodiscs (M2-nanodiscs) with M2 in a membrane-embedded tetrameric conformation, closely resembling its natural physiological state in the influenza viral envelope. M2-nanodisc generation, an antigen, was followed by Chiloscyllium plagiosum immunization. The functional vNARs were selected by phage display panning strategy from the shark immune library. One of the isolated vNARs, AM2H10, could specifically bind to tetrameric M2 instead of monomeric M2e (the ectodomain of M2 protein). Furthermore, AM2H10 blocked ion influx through amantadine-sensitive and resistant M2 channels. Our findings indicated the possibility of developing functional shark nanobodies against various influenza viruses by targeting the M2 protein.
Collapse
|
4
|
de Grip WJ, Ganapathy S. Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering. Front Chem 2022; 10:879609. [PMID: 35815212 PMCID: PMC9257189 DOI: 10.3389/fchem.2022.879609] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/16/2022] [Indexed: 01/17/2023] Open
Abstract
The first member and eponym of the rhodopsin family was identified in the 1930s as the visual pigment of the rod photoreceptor cell in the animal retina. It was found to be a membrane protein, owing its photosensitivity to the presence of a covalently bound chromophoric group. This group, derived from vitamin A, was appropriately dubbed retinal. In the 1970s a microbial counterpart of this species was discovered in an archaeon, being a membrane protein also harbouring retinal as a chromophore, and named bacteriorhodopsin. Since their discovery a photogenic panorama unfolded, where up to date new members and subspecies with a variety of light-driven functionality have been added to this family. The animal branch, meanwhile categorized as type-2 rhodopsins, turned out to form a large subclass in the superfamily of G protein-coupled receptors and are essential to multiple elements of light-dependent animal sensory physiology. The microbial branch, the type-1 rhodopsins, largely function as light-driven ion pumps or channels, but also contain sensory-active and enzyme-sustaining subspecies. In this review we will follow the development of this exciting membrane protein panorama in a representative number of highlights and will present a prospect of their extraordinary future potential.
Collapse
Affiliation(s)
- Willem J. de Grip
- Leiden Institute of Chemistry, Department of Biophysical Organic Chemistry, Leiden University, Leiden, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Srividya Ganapathy
- Department of Imaging Physics, Delft University of Technology, Netherlands
| |
Collapse
|
5
|
Khan AK, Jagielnicki M, Bennett BC, Purdy MD, Yeager M. Cryo-EM structure of an open conformation of a gap junction hemichannel in lipid bilayer nanodiscs. Structure 2021; 29:1040-1047.e3. [PMID: 34129834 PMCID: PMC9616683 DOI: 10.1016/j.str.2021.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 02/26/2021] [Accepted: 05/14/2021] [Indexed: 12/30/2022]
Abstract
To mediate cell-to-cell communication via gap junction channels (GJCs), connexins (Cx) traffic as hexameric hemichannels to the plasma membrane, which dock end-to-end between adjacent cell membranes, thereby forming a dodecameric intercellular conduit. Hemichannels also function independently to mediate the passage of contents between the cytoplasm and extracellular space. To generate hemichannels, the mutation N176Y was introduced into the second extracellular loop of Cx26. The electron cryomicroscopy structure of the hexameric hemichannel in lipid bilayer nanodiscs displays an open pore and a 4-helix bundle transmembrane design that is nearly identical to dodecameric GJCs. In contrast to the high resolution of the transmembrane α-helices, the extracellular loops are less well resolved. The conformational flexibility of the extracellular loops may be essential to facilitate surveillance of hemichannels in apposed cells to identify compatible Cx isoforms that enable intercellular docking. Our results also provide a structural foundation for previous electrophysiologic and permeation studies of Cx hemichannels.
Collapse
Affiliation(s)
- Ali K Khan
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Sheridan G. Snyder Translational Research Building, Rm 320, 480 Ray C. Hunt Drive, Charlottesville, VA 22908, USA
| | - Maciej Jagielnicki
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Sheridan G. Snyder Translational Research Building, Rm 320, 480 Ray C. Hunt Drive, Charlottesville, VA 22908, USA
| | - Brad C Bennett
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Sheridan G. Snyder Translational Research Building, Rm 320, 480 Ray C. Hunt Drive, Charlottesville, VA 22908, USA
| | - Michael D Purdy
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Sheridan G. Snyder Translational Research Building, Rm 320, 480 Ray C. Hunt Drive, Charlottesville, VA 22908, USA
| | - Mark Yeager
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Sheridan G. Snyder Translational Research Building, Rm 320, 480 Ray C. Hunt Drive, Charlottesville, VA 22908, USA; Center for Membrane Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Medicine, Division of Cardiovascular Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
| |
Collapse
|
6
|
Schmidpeter PAM, Nimigean CM. Correlating ion channel structure and function. Methods Enzymol 2021; 652:3-30. [PMID: 34059287 DOI: 10.1016/bs.mie.2021.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Recent developments in cryogenic electron microscopy (cryo-EM) led to an exponential increase in high-resolution structures of membrane proteins, and in particular ion channels. However, structures alone can only provide limited information about the workings of these proteins. In order to understand ion channel function and regulation in molecular detail, the obtained structural data need to be correlated to functional states of the same protein. Here, we describe several techniques that can be employed to study ion channel structure and function in vitro and under defined, similar conditions. Lipid nanodiscs provide a native-like environment for membrane proteins and have become a valuable tool in membrane protein structural biology and biophysics. Combined with liposome-based flux assays for the kinetic analysis of ion channel activity as well as electrophysiological recordings, researchers now have access to an array of experimental techniques allowing for detailed structure-function correlations using purified components. Two examples are presented where we put emphasis on the lipid environment and time-resolved techniques together with mutations and protein engineering to interpret structural data obtained from single particle cryo-EM on cyclic nucleotide-gated or Ca2+-gated K+ channels. Furthermore, we provide short protocols for all the assays used in our work so that others can adapt these techniques to their experimental needs. Comprehensive structure-function correlations are essential in order to pharmacologically target channelopathies.
Collapse
Affiliation(s)
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States.
| |
Collapse
|
7
|
Park PSH. Supramolecular organization of rhodopsin in rod photoreceptor cell membranes. Pflugers Arch 2021; 473:1361-1376. [PMID: 33591421 DOI: 10.1007/s00424-021-02522-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/12/2021] [Accepted: 01/18/2021] [Indexed: 11/30/2022]
Abstract
Rhodopsin is the light receptor in rod photoreceptor cells that initiates scotopic vision. Studies on the light receptor span well over a century, yet questions about the organization of rhodopsin within the photoreceptor cell membrane still persist and a consensus view on the topic is still elusive. Rhodopsin has been intensely studied for quite some time, and there is a wealth of information to draw from to formulate an organizational picture of the receptor in native membranes. Early experimental evidence in apparent support for a monomeric arrangement of rhodopsin in rod photoreceptor cell membranes is contrasted and reconciled with more recent visual evidence in support of a supramolecular organization of rhodopsin. What is known so far about the determinants of forming a supramolecular structure and possible functional roles for such an organization are also discussed. Many details are still missing on the structural and functional properties of the supramolecular organization of rhodopsin in rod photoreceptor cell membranes. The emerging picture presented here can serve as a springboard towards a more in-depth understanding of the topic.
Collapse
Affiliation(s)
- Paul S-H Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
| |
Collapse
|
8
|
Lee Y, Warne T, Nehmé R, Pandey S, Dwivedi-Agnihotri H, Chaturvedi M, Edwards PC, García-Nafría J, Leslie AGW, Shukla AK, Tate CG. Molecular basis of β-arrestin coupling to formoterol-bound β 1-adrenoceptor. Nature 2020; 583:862-866. [PMID: 32555462 DOI: 10.1038/s41586-020-2419-1] [Citation(s) in RCA: 144] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 04/07/2020] [Indexed: 12/15/2022]
Abstract
The β1-adrenoceptor (β1AR) is a G-protein-coupled receptor (GPCR) that couples1 to the heterotrimeric G protein Gs. G-protein-mediated signalling is terminated by phosphorylation of the C terminus of the receptor by GPCR kinases (GRKs) and by coupling of β-arrestin 1 (βarr1, also known as arrestin 2), which displaces Gs and induces signalling through the MAP kinase pathway2. The ability of synthetic agonists to induce signalling preferentially through either G proteins or arrestins-known as biased agonism3-is important in drug development, because the therapeutic effect may arise from only one signalling cascade, whereas the other pathway may mediate undesirable side effects4. To understand the molecular basis for arrestin coupling, here we determined the cryo-electron microscopy structure of the β1AR-βarr1 complex in lipid nanodiscs bound to the biased agonist formoterol5, and the crystal structure of formoterol-bound β1AR coupled to the G-protein-mimetic nanobody6 Nb80. βarr1 couples to β1AR in a manner distinct to that7 of Gs coupling to β2AR-the finger loop of βarr1 occupies a narrower cleft on the intracellular surface, and is closer to transmembrane helix H7 of the receptor when compared with the C-terminal α5 helix of Gs. The conformation of the finger loop in βarr1 is different from that adopted by the finger loop of visual arrestin when it couples to rhodopsin8. β1AR coupled to βarr1 shows considerable differences in structure compared with β1AR coupled to Nb80, including an inward movement of extracellular loop 3 and the cytoplasmic ends of H5 and H6. We observe weakened interactions between formoterol and two serine residues in H5 at the orthosteric binding site of β1AR, and find that formoterol has a lower affinity for the β1AR-βarr1 complex than for the β1AR-Gs complex. The structural differences between these complexes of β1AR provide a foundation for the design of small molecules that could bias signalling in the β-adrenoceptors.
Collapse
Affiliation(s)
- Yang Lee
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Tony Warne
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Rony Nehmé
- MRC Laboratory of Molecular Biology, Cambridge, UK.,Creoptix AG, Wädenswil, Switzerland
| | - Shubhi Pandey
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | | | - Madhu Chaturvedi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | | | - Javier García-Nafría
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, BIFI-IQFR (CSIC), Zaragoza, Spain.,Laboratorio de Microscopías Avanzadas, University of Zaragoza, Zaragoza, Spain
| | | | - Arun K Shukla
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | | |
Collapse
|
9
|
D'Agostino G, García-Cuesta EM, Gomariz RP, Rodríguez-Frade JM, Mellado M. The multilayered complexity of the chemokine receptor system. Biochem Biophys Res Commun 2020; 528:347-358. [PMID: 32145914 DOI: 10.1016/j.bbrc.2020.02.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/17/2020] [Accepted: 02/20/2020] [Indexed: 01/08/2023]
Abstract
The chemokines receptor family are membrane-expressed class A-specific seven-transmembrane receptors linked to G proteins. Through interaction with the corresponding ligands, the chemokines, they induce a wide variety of cellular responses including cell polarization, movement, immune and inflammatory responses, as well as the prevention of HIV-1 infection. Like a Russian matryoshka doll, the chemokine receptor system is more complex than initially envisaged. This review focuses on the mechanisms that contribute to this dazzling complexity and how they modulate the signaling events triggered by chemokines. The chemokines and their receptors exist as monomers, dimers and oligomers, their expression pattern is highly regulated, and the ligands can bind distinct receptors with similar affinities. The use of novel imaging-based technologies, particularly real-time imaging modalities, has shed new light on the very dynamic conformations that chemokine receptors adopt depending on the cellular context, and that affect chemokine-mediated responses. This complex scenario presents both challenging and exciting opportunities for drug discovery.
Collapse
Affiliation(s)
- Gianluca D'Agostino
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain
| | - Eva M García-Cuesta
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain
| | - Rosa P Gomariz
- Dept. Cell Biology, Complutense University of Madrid, Research Institute Hospital 12 de Octubre (i+12), E-28041, Madrid, Spain
| | - José Miguel Rodríguez-Frade
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain
| | - Mario Mellado
- Dept. Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus Cantoblanco, E-28049, Madrid, Spain.
| |
Collapse
|
10
|
Schmidpeter PAM, Sukomon N, Nimigean CM. Reconstitution of Membrane Proteins into Platforms Suitable for Biophysical and Structural Analyses. Methods Mol Biol 2020; 2127:191-205. [PMID: 32112324 PMCID: PMC9288841 DOI: 10.1007/978-1-0716-0373-4_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Integral membrane proteins have historically been challenging targets for biophysical research due to their low solubility in aqueous solution. Their importance for chemical and electrical signaling between cells, however, makes them fascinating targets for investigators interested in the regulation of cellular and physiological processes. Since membrane proteins shunt the barrier imposed by the cell membrane, they also serve as entry points for drugs, adding pharmaceutical research and development to the interests. In recent years, detailed understanding of membrane protein function has significantly increased due to high-resolution structural information obtained from single-particle cryo-EM, X-ray crystallography, and NMR. In order to further advance our mechanistic understanding on membrane proteins as well as foster drug development, it is crucial to generate more biophysical and functional data on these proteins under defined conditions. To that end, different techniques have been developed to stabilize integral membrane proteins in native-like environments that allow both structural and biophysical investigations-amphipols, lipid bicelles, and lipid nanodiscs. In this chapter, we provide detailed protocols for the reconstitution of membrane proteins according to these three techniques. We also outline some of the possible applications of each technique and discuss their advantages and possible caveats.
Collapse
Affiliation(s)
| | - Nattakan Sukomon
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA.
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
11
|
Feldman TB, Ivankov OI, Kuklin AI, Murugova TN, Yakovleva MA, Smitienko OA, Kolchugina IB, Round A, Gordeliy VI, Belushkin AV, Ostrovsky MA. Small-angle neutron and X-ray scattering analysis of the supramolecular organization of rhodopsin in photoreceptor membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183000. [DOI: 10.1016/j.bbamem.2019.05.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 01/16/2023]
|
12
|
Zhao DY, Pöge M, Morizumi T, Gulati S, Van Eps N, Zhang J, Miszta P, Filipek S, Mahamid J, Plitzko JM, Baumeister W, Ernst OP, Palczewski K. Cryo-EM structure of the native rhodopsin dimer in nanodiscs. J Biol Chem 2019; 294:14215-14230. [PMID: 31399513 DOI: 10.1074/jbc.ra119.010089] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 08/02/2019] [Indexed: 02/03/2023] Open
Abstract
Imaging of rod photoreceptor outer-segment disc membranes by atomic force microscopy and cryo-electron tomography has revealed that the visual pigment rhodopsin, a prototypical class A G protein-coupled receptor (GPCR), can organize as rows of dimers. GPCR dimerization and oligomerization offer possibilities for allosteric regulation of GPCR activity, but the detailed structures and mechanism remain elusive. In this investigation, we made use of the high rhodopsin density in the native disc membranes and of a bifunctional cross-linker that preserves the native rhodopsin arrangement by covalently tethering rhodopsins via Lys residue side chains. We purified cross-linked rhodopsin dimers and reconstituted them into nanodiscs for cryo-EM analysis. We present cryo-EM structures of the cross-linked rhodopsin dimer as well as a rhodopsin dimer reconstituted into nanodiscs from purified monomers. We demonstrate the presence of a preferential 2-fold symmetrical dimerization interface mediated by transmembrane helix 1 and the cytoplasmic helix 8 of rhodopsin. We confirmed this dimer interface by double electron-electron resonance measurements of spin-labeled rhodopsin. We propose that this interface and the arrangement of two protomers is a prerequisite for the formation of the observed rows of dimers. We anticipate that the approach outlined here could be extended to other GPCRs or membrane receptors to better understand specific receptor dimerization mechanisms.
Collapse
Affiliation(s)
- Dorothy Yanling Zhao
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Matthias Pöge
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Takefumi Morizumi
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Sahil Gulati
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, California 92697.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Ned Van Eps
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jianye Zhang
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, California 92697.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Przemyslaw Miszta
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw 02-093, Poland
| | - Slawomir Filipek
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw 02-093, Poland
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Oliver P Ernst
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, California 92697 .,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| |
Collapse
|
13
|
Rico CA, Berchiche YA, Horioka M, Peeler JC, Lorenzen E, Tian H, Kazmi MA, Fürstenberg A, Gaertner H, Hartley O, Sakmar TP, Huber T. High-Affinity Binding of Chemokine Analogs that Display Ligand Bias at the HIV-1 Coreceptor CCR5. Biophys J 2019; 117:903-919. [PMID: 31421836 DOI: 10.1016/j.bpj.2019.07.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/01/2019] [Accepted: 07/22/2019] [Indexed: 11/30/2022] Open
Abstract
The chemokine receptor CCR5 is a drug target to prevent transmission of HIV/AIDS. We studied four analogs of the native chemokine regulated, on activation, normal T-cell-expressed, and secreted (RANTES) (CCL5) that have anti-HIV potencies of around 25 pM, which is more than four orders of magnitude higher than that of RANTES itself. It has been hypothesized that the ultrahigh potency of the analogs is due to their ability to bind populations of receptors not accessible to native chemokines. To test this hypothesis, we developed a homogeneous dual-color fluorescence cross-correlation spectroscopy assay for saturation- and competition-binding experiments. The fluorescence cross-correlation spectroscopy assay has the advantage that it does not rely on competition with radioactively labeled native chemokines used in conventional assays. We prepared site-specifically labeled fluorescent analogs using native chemical ligation of synthetic peptides, followed by bioorthogonal fluorescent labeling. We engineered a mammalian cell expression construct to provide fluorescently labeled CCR5, which was purified using a tandem immunoaffinity and size-exclusion chromatography approach to obtain monomeric fluorescent CCR5 in detergent solution. We found subnanomolar binding affinities for the two analogs 5P12-RANTES and 5P14-RANTES and about 20-fold reduced affinities for PSC-RANTES and 6P4-RANTES. Using homologous and heterologous competition experiments with unlabeled chemokine analogs, we conclude that the analogs all bind at the same binding site, whereas the native chemokines (RANTES and MIP-1α) fail to displace bound fluorescent analogs even at tens of micromolar concentrations. Our results can be rationalized with de novo structural models of the N-terminal tails of the synthetic chemokines that adopt a different binding mode as compared to the parent compound.
Collapse
Affiliation(s)
- Carlos A Rico
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, New York
| | - Yamina A Berchiche
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, US National Institutes of Health, Bethesda, Maryland
| | - Mizuho Horioka
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, New York
| | - Jennifer C Peeler
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Deparment of Chemistry, Boston College, Chestnut Hill, Massachusetts
| | - Emily Lorenzen
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - He Tian
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - Manija A Kazmi
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - Alexandre Fürstenberg
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York; Department of Inorganic and Analytical Chemistry, Geneva, Switzerland
| | - Hubert Gaertner
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Oliver Hartley
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Thomas P Sakmar
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York
| | - Thomas Huber
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York.
| |
Collapse
|
14
|
Iric K, Subramanian M, Oertel J, Agarwal NP, Matthies M, Periole X, Sakmar TP, Huber T, Fahmy K, Schmidt TL. DNA-encircled lipid bilayers. NANOSCALE 2018; 10:18463-18467. [PMID: 30272763 DOI: 10.1039/c8nr06505e] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Lipid bilayers and lipid-associated proteins play crucial roles in biology. As in vivo studies and manipulation are inherently difficult, membrane-mimetic systems are useful for the investigation of lipidic phases, lipid-protein interactions, membrane protein function and membrane structure in vitro. In this work, we describe a route to leverage the programmability of DNA nanotechnology and create DNA-encircled bilayers (DEBs). DEBs are made of multiple copies of an alkylated oligonucleotide hybridized to a single-stranded minicircle, in which up to two alkyl chains per helical turn point to the inside of the toroidal DNA ring. When phospholipids are added, a bilayer is observed to self-assemble within the ring such that the alkyl chains of the oligonucleotides stabilize the hydrophobic rim of the bilayer to prevent formation of vesicles and support thermotropic lipid phase transitions. The DEBs are completely free of protein and can be synthesized from commercially available components using routine equipment. The diameter of DEBs can be varied in a predictable manner. The well-established toolbox from structural DNA nanotechnology, will ultimately enable the rational design of DEBs so that their size, shape or functionalization can be adapted to the specific needs of biophysical investigations of lipidic phases and the properties of membrane proteins embedded into DEB nanoparticle bilayers.
Collapse
Affiliation(s)
- Katarina Iric
- Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062 Dresden, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Culhane KJ, Belina ME, Sims JN, Cai Y, Liu Y, Wang PSP, Yan ECY. Parathyroid Hormone Senses Extracellular Calcium To Modulate Endocrine Signaling upon Binding to the Family B GPCR Parathyroid Hormone 1 Receptor. ACS Chem Biol 2018; 13:2347-2358. [PMID: 29952553 PMCID: PMC10640708 DOI: 10.1021/acschembio.8b00568] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Parathyroid hormone (PTH) binds to a family B G protein coupled receptor, parathyroid hormone 1 receptor (PTH1R). One of its functions is to regulate Ca2+ homeostasis in bone remodeling, during which Ca2+ can reach up to 40 mM. A truncated version of PTH, PTH(1-34), can fully activate PTH1R and has been used for osteoporosis treatments. Here, we used fluorescence anisotropy to examine the binding of PTH(1-34) to PTH1R purified in nanodiscs (PTH1R-ND) and found that the affinity increases 5-fold in the presence of 15 mM Ca2+. However, PTHrP(1-36), another truncated endogenous agonist for PTH1R, does not show this Ca2+ effect. Mutations of Glu19 and Glu22 in PTH(1-34) that are not conserved in PTHrP(1-36) largely abolished the Ca2+ effect. The results support that PTH(1-34) not only activates PTH1R but also uniquely senses Ca2+. This dual function of a peptide hormone is a novel observation that couples changes in extracellular environment with endocrine signaling. Understanding this can potentially reveal the complex role of PTH signaling in bone remodeling and improve the PTH(1-34) treatment for osteoporosis.
Collapse
Affiliation(s)
- Kelly J. Culhane
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Ave, New Haven, Connecticut 06520, USA
| | - Morgan E. Belina
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Jeremiah N. Sims
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Yingying Cai
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Yuting Liu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Pam S. P. Wang
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
| |
Collapse
|
16
|
Szundi I, Funatogawa C, Guo Y, Yan ECY, Kliger DS. Protein Sequence and Membrane Lipid Roles in the Activation Kinetics of Bovine and Human Rhodopsins. Biophys J 2017; 113:1934-1944. [PMID: 29117518 DOI: 10.1016/j.bpj.2017.08.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/26/2017] [Accepted: 08/28/2017] [Indexed: 12/17/2022] Open
Abstract
Rhodopsin is a G protein-coupled receptor found in the rod outer segments in the retina, which triggers a visual response under dim light conditions. Recently, a study of the late, microsecond-to-millisecond kinetics of photointermediates of the human and bovine rhodopsins in their native membranes revealed a complex, double-square mechanism of rhodopsin activation. In this kinetic scheme, the human rhodopsin exhibited more Schiff base deprotonation than bovine rhodopsin, which could arise from the ∼7% sequence difference between the two proteins, or from the difference between their membrane lipid environments. To differentiate between the effects of membrane and protein structure on the kinetics, the human and bovine rhodopsins were inserted into 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine lipid nanodiscs and the kinetics of activation at 15°C and pH 8.7 was investigated by time-resolved absorption spectroscopy and global kinetic analysis. For both proteins, the kinetics in nanodiscs shows the characteristics observed in the native membranes, and is described by a multisquare model with Schiff base deprotonation at the lumirhodopsin I intermediate stage. The results indicate that the protein sequence controls the extent of Schiff base deprotonation and accumulation of intermediates, and thus plays the main role in the different activation kinetics observed between human and bovine rhodopsins. The membrane lipid does have a minor role by modulating the timing of the kinetics, with the nanodisc environment leading to an earlier Schiff base deprotonation.
Collapse
Affiliation(s)
- Istvan Szundi
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Chie Funatogawa
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Ying Guo
- Department of Chemistry, Yale University, New Haven, Connecticut
| | - Elsa C Y Yan
- Department of Chemistry, Yale University, New Haven, Connecticut
| | - David S Kliger
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California.
| |
Collapse
|
17
|
Tian H, Sakmar TP, Huber T. Measurement of Slow Spontaneous Release of 11-cis-Retinal from Rhodopsin. Biophys J 2017; 112:153-161. [PMID: 28076806 DOI: 10.1016/j.bpj.2016.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/08/2016] [Accepted: 12/05/2016] [Indexed: 01/05/2023] Open
Abstract
The vertebrate visual photoreceptor rhodopsin (Rho) is a unique G protein-coupled receptor as it utilizes a covalently tethered inverse agonist (11-cis-retinal) as the native ligand. Previously, electrophysiological studies showed that ligand binding of 11-cis-retinal in dark-adapted Rho was essentially irreversible with a half-life estimated to be 420 years, until after thermal isomerization to all-trans-retinal, which then slowly dissociates. This long lifetime of 11-cis-retinal binding was considered to be physiologically important for minimizing background signal (dark noise) of the visual system. However, in vitro biochemical studies on the thermal stability of Rho showed that Rho decays with a half-life on the order of days. In this study, we resolve the discrepancy by measuring the chromophore exchange rate of the bound 11-cis-retinal chromophore with free 9-cis-retinal from Rho in an in vitro phospholipid/detergent bicelle system. We conclude that the thermal decay of Rho primarily proceeds through spontaneous breaking of the covalent linkage between opsin and 11-cis-retinal, which was overlooked in the electrophysiological recording. We estimate that this slow spontaneous release of 11-cis-retinal from Rho should result in 104 to 105 free opsin molecules in a dark-adapted rod cell-a number that is three orders of magnitude higher than previously expected. We also discuss the physiological implications of these findings on the basal activity of opsins and the associated dark noise in the visual system.
Collapse
Affiliation(s)
- He Tian
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, NY
| | - Thomas P Sakmar
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, NY; Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Huddinge, Sweden.
| | - Thomas Huber
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, NY.
| |
Collapse
|
18
|
Cai Y, Liu Y, Culhane KJ, DeVree BT, Yang Y, Sunahara RK, Yan ECY. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor. PLoS One 2017; 12:e0179568. [PMID: 28609478 PMCID: PMC5469476 DOI: 10.1371/journal.pone.0179568] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/31/2017] [Indexed: 12/16/2022] Open
Abstract
Family B G protein-coupled receptors (GPCRs) play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1) receptor (GLP1R), whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL) particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms.
Collapse
Affiliation(s)
- Yingying Cai
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
| | - Yuting Liu
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
| | - Kelly J. Culhane
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Brian T. DeVree
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Yang Yang
- Nanobiology Institute, Yale University, New Haven, Connecticut, United States of America
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Roger K. Sunahara
- Department of Pharmacology, University of California at San Diego, La Jolla, California, United States of America
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
| |
Collapse
|
19
|
The power, pitfalls and potential of the nanodisc system for NMR-based studies. Biol Chem 2016; 397:1335-1354. [DOI: 10.1515/hsz-2016-0224] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/19/2016] [Indexed: 12/21/2022]
Abstract
Abstract
The choice of a suitable membrane mimicking environment is of fundamental importance for the characterization of structure and function of membrane proteins. In this respect, usage of the lipid bilayer nanodisc technology provides a unique potential for nuclear magnetic resonance (NMR)-based studies. This review summarizes the recent advances in this field, focusing on (i) the strengths of the system, (ii) the bottlenecks that may be faced, and (iii) promising capabilities that may be explored in future studies.
Collapse
|
20
|
Periole X. Interplay of G Protein-Coupled Receptors with the Membrane: Insights from Supra-Atomic Coarse Grain Molecular Dynamics Simulations. Chem Rev 2016; 117:156-185. [PMID: 28073248 DOI: 10.1021/acs.chemrev.6b00344] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
G protein-coupled receptors (GPCRs) are central to many fundamental cellular signaling pathways. They transduce signals from the outside to the inside of cells in physiological processes ranging from vision to immune response. It is extremely challenging to look at them individually using conventional experimental techniques. Recently, a pseudo atomistic molecular model has emerged as a valuable tool to access information on GPCRs, more specifically on their interactions with their environment in their native cell membrane and the consequences on their supramolecular organization. This approach uses the Martini coarse grain (CG) model to describe the receptors, lipids, and solvent in molecular dynamics (MD) simulations and in enough detail to allow conserving the chemical specificity of the different molecules. The elimination of unnecessary degrees of freedom has opened up large-scale simulations of the lipid-mediated supramolecular organization of GPCRs. Here, after introducing the Martini CGMD method, we review these studies carried out on various members of the GPCR family, including rhodopsin (visual receptor), opioid receptors, adrenergic receptors, adenosine receptors, dopamine receptor, and sphingosine 1-phosphate receptor. These studies have brought to light an interesting set of novel biophysical principles. The insights range from revealing localized and heterogeneous deformations of the membrane bilayer at the surface of the protein, specific interactions of lipid molecules with individual GPCRs, to the effect of the membrane matrix on global GPCR self-assembly. The review ends with an overview of the lessons learned from the use of the CGMD method, the biophysical-chemical findings on lipid-protein interplay.
Collapse
Affiliation(s)
- Xavier Periole
- Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747AG Groningen, The Netherlands
| |
Collapse
|
21
|
Quaternary structures of opsin in live cells revealed by FRET spectrometry. Biochem J 2016; 473:3819-3836. [PMID: 27623775 DOI: 10.1042/bcj20160422] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/12/2016] [Indexed: 02/06/2023]
Abstract
Rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that initiates phototransduction in the retina. The receptor consists of the apoprotein opsin covalently linked to the inverse agonist 11-cis retinal. Rhodopsin and opsin have been shown to form oligomers within the outer segment disc membranes of rod photoreceptor cells. However, the physiological relevance of the observed oligomers has been questioned since observations were made on samples prepared from the retina at low temperatures. To investigate the oligomeric status of opsin in live cells at body temperatures, we utilized a novel approach called Förster resonance energy transfer spectrometry, which previously has allowed the determination of the stoichiometry and geometry (i.e. quaternary structure) of various GPCRs. In the current study, we have extended the method to additionally determine whether or not a mixture of oligomeric forms of opsin exists and in what proportion. The application of this improved method revealed that opsin expressed in live Chinese hamster ovary (CHO) cells at 37°C exists as oligomers of various sizes. At lower concentrations, opsin existed in an equilibrium of dimers and tetramers. The tetramers were in the shape of a near-rhombus. At higher concentrations of the receptor, higher-order oligomers began to form. Thus, a mixture of different oligomeric forms of opsin is present in the membrane of live CHO cells and oligomerization occurs in a concentration-dependent manner. The general principles underlying the concentration-dependent oligomerization of opsin may be universal and apply to other GPCRs as well.
Collapse
|
22
|
Tuning the Photocycle Kinetics of Bacteriorhodopsin in Lipid Nanodiscs. Biophys J 2016; 109:1899-906. [PMID: 26536266 DOI: 10.1016/j.bpj.2015.09.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/19/2015] [Accepted: 09/11/2015] [Indexed: 11/22/2022] Open
Abstract
Monodisperse lipid nanodiscs are particularly suitable for characterizing membrane protein in near-native environment. To study the lipid-composition dependence of photocycle kinetics of bacteriorhodopsin (bR), transient absorption spectroscopy was utilized to monitor the evolution of the photocycle intermediates of bR reconstituted in nanodiscs composed of different ratios of the zwitterionic lipid (DMPC, dimyristoyl phosphatidylcholine; DOPC, dioleoyl phosphatidylcholine) to the negatively charged lipid (DOPG, dioleoyl phosphatidylglycerol; DMPG, dimyristoyl phosphatidylglycerol). The characterization of ion-exchange chromatography showed that the negative surface charge of nanodiscs increased as the content of DOPG or DMPG was increased. The steady-state absorption contours of the light-adapted monomeric bR in nanodiscs composed of different lipid ratios exhibited highly similar absorption features of the retinal moiety at 560 nm, referring to the conservation of the tertiary structure of bR in nanodiscs of different lipid compositions. In addition, transient absorption contours showed that the photocycle kinetics of bR was significantly retarded and the transient populations of intermediates N and O were decreased as the content of DMPG or DOPG was reduced. This observation could be attributed to the negatively charged lipid heads of DMPG and DOPG, exhibiting similar proton relay capability as the native phosphatidylglycerol (PG) analog lipids in the purple membrane. In this work, we not only demonstrated the usefulness of nanodiscs as a membrane-mimicking system, but also showed that the surrounding lipids play a crucial role in altering the biological functions, e.g., the ion translocation kinetics of the transmembrane proteins.
Collapse
|
23
|
Abstract
It is a deeply engrained notion that the visual pigment rhodopsin signals light as a monomer, even though many G protein-coupled receptors are now known to exist and function as dimers. Nonetheless, recent studies (albeit all in vitro) have suggested that rhodopsin and its chromophore-free apoprotein, R-opsin, may indeed exist as a homodimer in rod disk membranes. Given the overwhelmingly strong historical context, the crucial remaining question, therefore, is whether pigment dimerization truly exists naturally and what function this dimerization may serve. We addressed this question in vivo with a unique mouse line (S-opsin(+)Lrat(-/-)) expressing, transgenically, short-wavelength-sensitive cone opsin (S-opsin) in rods and also lacking chromophore to exploit the fact that cone opsins, but not R-opsin, require chromophore for proper folding and trafficking to the photoreceptor's outer segment. In R-opsin's absence, S-opsin in these transgenic rods without chromophore was mislocalized; in R-opsin's presence, however, S-opsin trafficked normally to the rod outer segment and produced functional S-pigment upon subsequent chromophore restoration. Introducing a competing R-opsin transmembrane helix H1 or helix H8 peptide, but not helix H4 or helix H5 peptide, into these transgenic rods caused mislocalization of R-opsin and S-opsin to the perinuclear endoplasmic reticulum. Importantly, a similar peptide-competition effect was observed even in WT rods. Our work provides convincing evidence for visual pigment dimerization in vivo under physiological conditions and for its role in pigment maturation and targeting. Our work raises new questions regarding a potential mechanistic role of dimerization in rhodopsin signaling.
Collapse
|
24
|
Tian H, Fürstenberg A, Huber T. Labeling and Single-Molecule Methods To Monitor G Protein-Coupled Receptor Dynamics. Chem Rev 2016; 117:186-245. [DOI: 10.1021/acs.chemrev.6b00084] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- He Tian
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Alexandre Fürstenberg
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Thomas Huber
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| |
Collapse
|
25
|
Imamoto Y, Kojima K, Oka T, Maeda R, Shichida Y. Helical rearrangement of photoactivated rhodopsin in monomeric and dimeric forms probed by high-angle X-ray scattering. Photochem Photobiol Sci 2016; 14:1965-73. [PMID: 26293780 DOI: 10.1039/c5pp00175g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Light-induced helical rearrangement of vertebrate visual rhodopsin was directly monitored by high-angle X-ray scattering (HAXS), ranging from Q (= 4π sin θ/λ) = 0.03 Å(-1) to Q = 1.5 Å(-1). HAXS of nanodiscs containing a single rhodopsin molecule was performed before and after photoactivation of rhodopsin. The intensity difference curve obtained by HAXS agreed with that calculated from the crystal structure of dark state rhodopsin and metarhodopsin II, indicating that the conformational change of monomeric rhodopsin in the membrane is consistent with that occurring in the crystal. On the other hand, the HAXS intensity difference curve of nanodiscs containing two rhodopsin molecules was significantly reduced, similar to that calculated from the crystal structure of the deprotonated intermediate, without a large conformational change. These results suggest that rhodopsin is dimerized in the membrane and that the interaction between rhodopsin molecules modulates structural changes.
Collapse
Affiliation(s)
- Yasushi Imamoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Keiichi Kojima
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Toshihiko Oka
- Department of Physics, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan and Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka 432-8011, Japan
| | - Ryo Maeda
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| |
Collapse
|
26
|
Gao Y, Cao E, Julius D, Cheng Y. TRPV1 structures in nanodiscs reveal mechanisms of ligand and lipid action. Nature 2016; 534:347-51. [PMID: 27281200 PMCID: PMC4911334 DOI: 10.1038/nature17964] [Citation(s) in RCA: 596] [Impact Index Per Article: 74.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/31/2016] [Indexed: 12/23/2022]
Abstract
When integral membrane proteins are visualized in detergents or other artificial systems, an important layer of information is lost regarding lipid interactions and their effects on protein structure. This is especially relevant to proteins for which lipids play both structural and regulatory roles. Here, we demonstrate the power of combining electron cryo-microscopy with lipid nanodisc technology to ascertain the structure of the TRPV1 ion channel in a native bilayer environment. Using this approach, we determined the locations of annular and regulatory lipids and showed that specific phospholipid interactions enhance binding of a spider toxin to TRPV1 through formation of a tripartite complex. Furthermore, phosphatidylinositol lipids occupy the binding site for capsaicin and other vanilloid ligands, suggesting a mechanism whereby chemical or thermal stimuli elicit channel activation by promoting release of bioactive lipids from a critical allosteric regulatory site.
Collapse
Affiliation(s)
- Yuan Gao
- Department of Physiology, University of California, San Francisco, California 94143, USA.,Keck Advanced Microscopy Laboratory and Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143, USA
| | - Erhu Cao
- Department of Physiology, University of California, San Francisco, California 94143, USA
| | - David Julius
- Department of Physiology, University of California, San Francisco, California 94143, USA
| | - Yifan Cheng
- Keck Advanced Microscopy Laboratory and Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143, USA.,Howard Hughes Medical Institute, University of California, San Francisco, California 94143, USA
| |
Collapse
|
27
|
Li B, Makino SI, Beebe ET, Urano D, Aceti DJ, Misenheimer TM, Peters J, Fox BG, Jones AM. Cell-free translation and purification of Arabidopsis thaliana regulator of G signaling 1 protein. Protein Expr Purif 2016; 126:33-41. [PMID: 27164033 DOI: 10.1016/j.pep.2016.04.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 04/12/2016] [Accepted: 04/28/2016] [Indexed: 01/21/2023]
Abstract
Arabidopsis thaliana Regulator of G protein Signalling 1 (AtRGS1) is a protein with a predicted N-terminal 7-transmembrane (7TM) domain and a C-terminal cytosolic RGS1 box domain. The RGS1 box domain exerts GTPase activation (GAP) activity on Gα (AtGPA1), a component of heterotrimeric G protein signaling in plants. AtRGS1 may perceive an exogenous agonist to regulate the steady-state levels of the active form of AtGPA1. It is uncertain if the full-length AtRGS1 protein exerts any atypical effects on Gα, nor has it been established exactly how AtRGS1 contributes to perception of an extracellular signal and transmits this response to a G-protein dependent signaling cascade. Further studies on full-length AtRGS1 have been inhibited due to the extreme low abundance of the endogenous AtRGS1 protein in plants and lack of a suitable heterologous system to express AtRGS1. Here, we describe methods to produce full-length AtRGS1 by cell-free synthesis into unilamellar liposomes and nanodiscs. The cell-free synthesized AtRGS1 exhibits GTPase activating activity on Gα and can be purified to a level suitable for biochemical analyses.
Collapse
Affiliation(s)
- Bo Li
- Department of Biology, University of North Carolina at Chapel Hill, United States
| | - Shin-Ichi Makino
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Emily T Beebe
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Daisuke Urano
- Department of Biology, University of North Carolina at Chapel Hill, United States
| | - David J Aceti
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Tina M Misenheimer
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Jonathan Peters
- Department of Biology, University of North Carolina at Chapel Hill, United States
| | - Brian G Fox
- Transmembrane Protein Center, University of Wisconsin-Madison, United States
| | - Alan M Jones
- Department of Biology, University of North Carolina at Chapel Hill, United States; Department of Pharmacology, University of North Carolina at Chapel Hill, United States.
| |
Collapse
|
28
|
Culhane KJ, Liu Y, Cai Y, Yan ECY. Transmembrane signal transduction by peptide hormones via family B G protein-coupled receptors. Front Pharmacol 2015; 6:264. [PMID: 26594176 PMCID: PMC4633518 DOI: 10.3389/fphar.2015.00264] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/23/2015] [Indexed: 01/28/2023] Open
Abstract
Although family B G protein-coupled receptors (GPCRs) contain only 15 members, they play key roles in transmembrane signal transduction of hormones. Family B GPCRs are drug targets for developing therapeutics for diseases ranging from metabolic to neurological disorders. Despite their importance, the molecular mechanism of activation of family B GPCRs remains largely unexplored due to the challenges in expression and purification of functional receptors to the quantity for biophysical characterization. Currently, there is no crystal structure available of a full-length family B GPCR. However, structures of key domains, including the extracellular ligand binding regions and seven-helical transmembrane regions, have been solved by X-ray crystallography and NMR, providing insights into the mechanisms of ligand recognition and selectivity, and helical arrangements within the cell membrane. Moreover, biophysical and biochemical methods have been used to explore functions, key residues for signaling, and the kinetics and dynamics of signaling processes. This review summarizes the current knowledge of the signal transduction mechanism of family B GPCRs at the molecular level and comments on the challenges and outlook for mechanistic studies of family B GPCRs.
Collapse
Affiliation(s)
- Kelly J Culhane
- Department of Molecular Biophysics and Biochemistry, Yale University New Haven, CT, USA
| | - Yuting Liu
- Department of Chemistry, Yale University New Haven, CT, USA
| | - Yingying Cai
- Department of Chemistry, Yale University New Haven, CT, USA
| | - Elsa C Y Yan
- Department of Chemistry, Yale University New Haven, CT, USA
| |
Collapse
|
29
|
Van Eps N, Caro LN, Morizumi T, Ernst OP. Characterizing rhodopsin signaling by EPR spectroscopy: from structure to dynamics. Photochem Photobiol Sci 2015; 14:1586-97. [PMID: 26140679 DOI: 10.1039/c5pp00191a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy, together with spin labeling techniques, has played a major role in the characterization of rhodopsin, the photoreceptor protein and G protein-coupled receptor (GPCR) in rod cells. Two decades ago, these biophysical tools were the first to identify transmembrane helical movements in rhodopsin upon photo-activation, a critical step in the study of GPCR signaling. EPR methods were employed to identify functional loop dynamics within rhodopsin, to measure light-induced millisecond timescale changes in rhodopsin conformation, to characterize the effects of partial agonists on the apoprotein opsin, and to study lipid interactions with rhodopsin. With the emergence of advanced pulsed EPR techniques, the stage was set to determine the amplitude of structural changes in rhodopsin and the dynamics in the rhodopsin signaling complexes. Work in this area has yielded invaluable information about mechanistic properties of GPCRs. Using EPR techniques, receptors are studied in native-like membrane environments and the effects of lipids on conformational equilibria can be explored. This perspective addresses the impact of EPR methods on rhodopsin and GPCR structural biology, highlighting historical discoveries made with spin labeling techniques, and outlining exciting new directions in the field.
Collapse
Affiliation(s)
- Ned Van Eps
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | | | | | | |
Collapse
|
30
|
Staljanssens D, Rico CA, Park M, Van Camp J, Yu N, Huber T, Sakmar TP, Smagghe G. Development of a CCK1R-membrane nanoparticle as a fish-out tool for bioactive peptides. Peptides 2015; 68:219-27. [PMID: 25451329 DOI: 10.1016/j.peptides.2014.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/17/2014] [Accepted: 10/20/2014] [Indexed: 11/22/2022]
Abstract
The cholecystokinin receptor type 1 (CCK1R) is a G protein-coupled receptor (GPCR) that is involved in several biological processes including the regulation of the secretion of digestive enzymes. The peptide hormone cholecystokinin (CCK) binds to CCK1R, which is an important pharmacological target for several diseases, including obesity. Interestingly, nutritional dietary peptides also appear to activate CCK1R, and may play a role in CCK1R signaling in the gut. In this study, a novel technique to screen for CCK1R ligands based on affinity-selection is described. Functional expressed CCK1R is reconstituted into membrane nanoparticles called NABBs (nanoscale apo-lipoprotein bound bilayers). NABBs are native-like bilayer membrane systems for incorporation of GPCRs. CCK1R-NABBs were characterized using a fluorescently labeled CCK analog and can be used as a cutting-edge technology to screen for CCK1R ligands using affinity-selection mass spectrometry.
Collapse
Affiliation(s)
- Dorien Staljanssens
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium; Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Carlos A Rico
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA
| | - Minyoung Park
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA
| | - John Van Camp
- Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Na Yu
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Thomas Huber
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA
| | - Thomas P Sakmar
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA; Center for Alzheimer Research, Division for Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institute, SE-141 57 Huddinge, Sweden
| | - Guy Smagghe
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| |
Collapse
|
31
|
Biosensor-based affinities and binding kinetics of small molecule antagonists to the adenosine A(2A) receptor reconstituted in HDL like particles. FEBS Lett 2015; 589:1399-405. [PMID: 25935416 DOI: 10.1016/j.febslet.2015.04.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/14/2015] [Accepted: 04/17/2015] [Indexed: 11/23/2022]
Abstract
The options for investigating solubilised G protein-coupled receptors (GPCRs) by biophysical techniques have long been hampered by their instability. A thermostabilised adenosine A2A receptor expressed in insect cells, purified in detergent and reconstituted into high-density lipoprotein (HDL) particles was immobilised onto a Surface Plasmon Resonance sensor chip. This allowed measurement of affinities and kinetics for A2A antagonists with affinities ranging from 50 pM to almost 2 μM. Compared with other formats, reproduction of affinities, and dissociation and association rate constants are good, reasonable and poor respectively, indicating stabilised receptors in HDL particles are useful for investigating specific aspects of GPCR-ligand interactions.
Collapse
|
32
|
G-protein coupled receptor solubilization and purification for biophysical analysis and functional studies, in the total absence of detergent. Biosci Rep 2015; 35:BSR20140171. [PMID: 25720391 PMCID: PMC4400634 DOI: 10.1042/bsr20140171] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
G-protein coupled receptors (GPCRs) constitute the largest class of membrane proteins and are a major drug target. A serious obstacle to studying GPCR structure/function characteristics is the requirement to extract the receptors from their native environment in the plasma membrane, coupled with the inherent instability of GPCRs in the detergents required for their solubilization. In the present study, we report the first solubilization and purification of a functional GPCR [human adenosine A2A receptor (A2AR)], in the total absence of detergent at any stage, by exploiting spontaneous encapsulation by styrene maleic acid (SMA) co-polymer direct from the membrane into a nanoscale SMA lipid particle (SMALP). Furthermore, the A2AR–SMALP, generated from yeast (Pichia pastoris) or mammalian cells, exhibited increased thermostability (∼5°C) compared with detergent [DDM (n-dodecyl-β-D-maltopyranoside)]-solubilized A2AR controls. The A2AR–SMALP was also stable when stored for prolonged periods at 4°C and was resistant to multiple freeze-thaw cycles, in marked contrast with the detergent-solubilized receptor. These properties establish the potential for using GPCR–SMALP in receptor-based drug discovery assays. Moreover, in contrast with nanodiscs stabilized by scaffold proteins, the non-proteinaceous nature of the SMA polymer allowed unobscured biophysical characterization of the embedded receptor. Consequently, CD spectroscopy was used to relate changes in secondary structure to loss of ligand binding ([3H]ZM241385) capability. SMALP-solubilization of GPCRs, retaining the annular lipid environment, will enable a wide range of therapeutic targets to be prepared in native-like state to aid drug discovery and understanding of GPCR molecular mechanisms. It is universally acknowledged that exposing cell-surface receptors to detergent is detrimental. We have used a polymer to extract the receptor and surrounding lipid as a nanoparticle that provides a novel solution compatible with purification and receptor-based drug discovery assays.
Collapse
|
33
|
Saha SC, Powl AM, Wallace BA, de Planque MRR, Morgan H. Screening ion-channel ligand interactions with passive pumping in a microfluidic bilayer lipid membrane chip. BIOMICROFLUIDICS 2015; 9:014103. [PMID: 25610515 PMCID: PMC4288537 DOI: 10.1063/1.4905313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 12/19/2014] [Indexed: 05/16/2023]
Abstract
We describe a scalable artificial bilayer lipid membrane platform for rapid electrophysiological screening of ion channels and transporters. A passive pumping method is used to flow microliter volumes of ligand solution across a suspended bilayer within a microfluidic chip. Bilayers are stable at flow rates up to ∼0.5 μl/min. Phospholipid bilayers are formed across a photolithographically defined aperture made in a dry film resist within the microfluidic chip. Bilayers are stable for many days and the low shunt capacitance of the thin film support gives low-noise high-quality single ion channel recording. Dose-dependent transient blocking of α-hemolysin with β-cyclodextrin (β-CD) and polyethylene glycol is demonstrated and dose-dependent blocking studies of the KcsA potassium channel with tetraethylammonium show the potential for determining IC50 values. The assays are fast (30 min for a complete IC50 curve) and simple and require very small amounts of compounds (100 μg in 15 μl). The technology can be scaled so that multiple bilayers can be addressed, providing a screening platform for ion channels, transporters, and nanopores.
Collapse
Affiliation(s)
- Shimul C Saha
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Andrew M Powl
- Institute of Structural and Molecular Biology, Birkbeck College, University of London , London WC1E 7HX, United Kingdom
| | - B A Wallace
- Institute of Structural and Molecular Biology, Birkbeck College, University of London , London WC1E 7HX, United Kingdom
| | - Maurits R R de Planque
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Hywel Morgan
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton , Southampton SO17 1BJ, United Kingdom
| |
Collapse
|
34
|
Adamson RJ, Watts A. Kinetics of the early events of GPCR signalling. FEBS Lett 2014; 588:4701-7. [PMID: 25447525 PMCID: PMC4266533 DOI: 10.1016/j.febslet.2014.10.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/10/2014] [Accepted: 10/27/2014] [Indexed: 11/28/2022]
Abstract
Little is known of the kinetics of interactions between GPCRs and their signalling partners. NTS1 binds Gαi1 and Gαs with affinities of 15 ± 6 nM and 31 ± 18 nM (SE), respectively. This SPR assay may be applicable to multiple partners in the signalling cascade. We provide the first direct evidence for GPCR-G protein coupling in nanodiscs.
Neurotensin receptor type 1 (NTS1) is a G protein-coupled receptor (GPCR) that affects cellular responses by initiating a cascade of interactions through G proteins. The kinetic details for these interactions are not well-known. Here, NTS1-nanodisc-Gαs and Gαi1 interactions were studied. The binding affinities of Gαi1 and Gαs to NTS1 were directly measured by surface plasmon resonance (SPR) and determined to be 15 ± 6 nM and 31 ± 18 nM, respectively. This SPR configuration permits the kinetics of early events in signalling pathways to be explored and can be used to initiate descriptions of the GPCR interactome.
Collapse
Affiliation(s)
- Roslin J Adamson
- Biomembrane Structure Unit, Biochemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Anthony Watts
- Biomembrane Structure Unit, Biochemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
| |
Collapse
|
35
|
Huber T, Sakmar T. Chemical Biology Methods for Investigating G Protein-Coupled Receptor Signaling. ACTA ACUST UNITED AC 2014; 21:1224-37. [DOI: 10.1016/j.chembiol.2014.08.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/21/2014] [Accepted: 08/20/2014] [Indexed: 11/26/2022]
|
36
|
Redka DS, Morizumi T, Elmslie G, Paranthaman P, Shivnaraine RV, Ellis J, Ernst OP, Wells JW. Coupling of g proteins to reconstituted monomers and tetramers of the M2 muscarinic receptor. J Biol Chem 2014; 289:24347-65. [PMID: 25023280 DOI: 10.1074/jbc.m114.559294] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
G protein-coupled receptors can be reconstituted as monomers in nanodiscs and as tetramers in liposomes. When reconstituted with G proteins, both forms enable an allosteric interaction between agonists and guanylyl nucleotides. Both forms, therefore, are candidates for the complex that controls signaling at the level of the receptor. To identify the biologically relevant form, reconstituted monomers and tetramers of the purified M2 muscarinic receptor were compared with muscarinic receptors in sarcolemmal membranes for the effect of guanosine 5'-[β,γ-imido]triphosphate (GMP-PNP) on the inhibition of N-[(3)H]methylscopolamine by the agonist oxotremorine-M. With monomers, a stepwise increase in the concentration of GMP-PNP effected a lateral, rightward shift in the semilogarithmic binding profile (i.e. a progressive decrease in the apparent affinity of oxotremorine-M). With tetramers and receptors in sarcolemmal membranes, GMP-PNP effected a vertical, upward shift (i.e. an apparent redistribution of sites from a state of high affinity to one of low affinity with no change in affinity per se). The data were analyzed in terms of a mechanistic scheme based on a ligand-regulated equilibrium between uncoupled and G protein-coupled receptors (the "ternary complex model"). The model predicts a rightward shift in the presence of GMP-PNP and could not account for the effects at tetramers in vesicles or receptors in sarcolemmal membranes. Monomers present a special case of the model in which agonists and guanylyl nucleotides interact within a complex that is both constitutive and stable. The results favor oligomers of the M2 receptor over monomers as the biologically relevant state for coupling to G proteins.
Collapse
Affiliation(s)
- Dar'ya S Redka
- From the Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Takefumi Morizumi
- the Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Gwendolynne Elmslie
- the Departments of Psychiatry and Pharmacology, Hershey Medical Center, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033, and
| | - Pranavan Paranthaman
- From the Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Rabindra V Shivnaraine
- From the Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - John Ellis
- the Departments of Psychiatry and Pharmacology, Hershey Medical Center, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033, and
| | - Oliver P Ernst
- the Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada, the Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James W Wells
- From the Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada,
| |
Collapse
|
37
|
McCoy JG, Rusinova R, Kim DM, Kowal J, Banerjee S, Jaramillo Cartagena A, Thompson AN, Kolmakova-Partensky L, Stahlberg H, Andersen OS, Nimigean CM. A KcsA/MloK1 chimeric ion channel has lipid-dependent ligand-binding energetics. J Biol Chem 2014; 289:9535-46. [PMID: 24515111 DOI: 10.1074/jbc.m113.543389] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cyclic nucleotide-modulated ion channels play crucial roles in signal transduction in eukaryotes. The molecular mechanism by which ligand binding leads to channel opening remains poorly understood, due in part to the lack of a robust method for preparing sufficient amounts of purified, stable protein required for structural and biochemical characterization. To overcome this limitation, we designed a stable, highly expressed chimeric ion channel consisting of the transmembrane domains of the well characterized potassium channel KcsA and the cyclic nucleotide-binding domains of the prokaryotic cyclic nucleotide-modulated channel MloK1. This chimera demonstrates KcsA-like pH-sensitive activity which is modulated by cAMP, reminiscent of the dual modulation in hyperpolarization-activated and cyclic nucleotide-gated channels that display voltage-dependent activity that is also modulated by cAMP. Using this chimeric construct, we were able to measure for the first time the binding thermodynamics of cAMP to an intact cyclic nucleotide-modulated ion channel using isothermal titration calorimetry. The energetics of ligand binding to channels reconstituted in lipid bilayers are substantially different from those observed in detergent micelles, suggesting that the conformation of the chimera's transmembrane domain is sensitive to its (lipid or lipid-mimetic) environment and that ligand binding induces conformational changes in the transmembrane domain. Nevertheless, because cAMP on its own does not activate these chimeric channels, cAMP binding likely has a smaller energetic contribution to gating than proton binding suggesting that there is only a small difference in cAMP binding energy between the open and closed states of the channel.
Collapse
|
38
|
|
39
|
Kojima K, Imamoto Y, Maeda R, Yamashita T, Shichida Y. Rod visual pigment optimizes active state to achieve efficient G protein activation as compared with cone visual pigments. J Biol Chem 2013; 289:5061-73. [PMID: 24375403 DOI: 10.1074/jbc.m113.508507] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most vertebrate retinas contain two types of photoreceptor cells, rods and cones, which show different photoresponses to mediate scotopic and photopic vision, respectively. These cells contain different types of visual pigments, rhodopsin and cone visual pigments, respectively, but little is known about the molecular properties of cone visual pigments under physiological conditions, making it difficult to link the molecular properties of rhodopsin and cone visual pigments with the differences in photoresponse between rods and cones. Here we prepared bovine and mouse rhodopsin (bvRh and mRh) and chicken and mouse green-sensitive cone visual pigments (cG and mG) embedded in nanodiscs and applied time-resolved fluorescence spectroscopy to compare their Gt activation efficiencies. Rhodopsin exhibited greater Gt activation efficiencies than cone visual pigments. Especially, the Gt activation efficiency of mRh was about 2.5-fold greater than that of mG at 37 °C, which is consistent with our previous electrophysiological data of knock-in mice. Although the active state (Meta-II) was in equilibrium with inactive states (Meta-I and Meta-III), quantitative determination of Meta-II in the equilibrium showed that the Gt activation efficiency per Meta-II of bvRh was also greater than those of cG and mG. These results indicated that efficient Gt activation by rhodopsin, resulting from an optimized active state of rhodopsin, is one of the causes of the high amplification efficiency of rods.
Collapse
Affiliation(s)
- Keiichi Kojima
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | | | | | | | | |
Collapse
|
40
|
D'Antona AM, Xie G, Sligar SG, Oprian DD. Assembly of an activated rhodopsin-transducin complex in nanoscale lipid bilayers. Biochemistry 2013; 53:127-34. [PMID: 24328127 DOI: 10.1021/bi4012995] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The formation and characterization of an activated complex of the visual pigment rhodopsin and its downstream signaling partner transducin have been the subject of intense focus by several research groups. While the subunit composition of the activated complex is still the subject of some controversy, our laboratory [Xie, G., D'Antona, A. M., Edwards, P. C., Fransen, M., Standfuss, J., Schertler, G. F. X., and Oprian, D. D. (2011) Biochemistry 50, 10399-10407] and that of Ernst et al. [Ernst, O. P., Gramse, V., Kolbe, M., Hofmann, K. P., and Heck, M. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 10859-10864] find that the two proteins are present in a 1/1 molar ratio. Unfortunately, these data could not distinguish a ratio of 1/1 from ratios of 2/2, 3/3, etc. For this reason, we reinvestigated the issue of stoichiometry of the activated complex, exploiting the ability of Nanodisc lipid bilayers to isolate single molecules of rhodopsin. We show here that the purified complex in Nanodiscs contains an activated rhodopsin with a covalently bound all-trans-retinal chromophore, that transducin has an empty nucleotide-binding pocket, that the isolated complex is active and dissociates upon addition of guanine nucleotide, and that the stoichiometry corresponds to exactly one molecule of rhodopsin and one molecule of transducin.
Collapse
Affiliation(s)
- Aaron M D'Antona
- Department of Biochemistry and Volen Center for Complex Systems, Brandeis University , Waltham, Massachusetts 02454, United States
| | | | | | | |
Collapse
|
41
|
Vishnivetskiy SA, Ostermaier MK, Singhal A, Panneels V, Homan KT, Glukhova A, Sligar SG, Tesmer JJG, Schertler GF, Standfuss J, Gurevich VV. Constitutively active rhodopsin mutants causing night blindness are effectively phosphorylated by GRKs but differ in arrestin-1 binding. Cell Signal 2013; 25:2155-62. [PMID: 23872075 PMCID: PMC3774132 DOI: 10.1016/j.cellsig.2013.07.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 07/11/2013] [Indexed: 11/24/2022]
Abstract
The effects of activating mutations associated with night blindness on the stoichiometry of rhodopsin interactions with G protein-coupled receptor kinase 1 (GRK1) and arrestin-1 have not been reported. Here we show that the monomeric form of WT rhodopsin and its constitutively active mutants M257Y, G90D, and T94I, reconstituted into HDL particles are effectively phosphorylated by GRK1, as well as two more ubiquitously expressed subtypes, GRK2 and GRK5. All versions of arrestin-1 tested (WT, pre-activated, and constitutively monomeric mutants) bind to monomeric rhodopsin and show the same selectivity for different functional forms of rhodopsin as in native disc membranes. Rhodopsin phosphorylation by GRK1 and GRK2 promotes arrestin-1 binding to a comparable extent, whereas similar phosphorylation by GRK5 is less effective, suggesting that not all phosphorylation sites on rhodopsin are equivalent in promoting arrestin-1 binding. The binding of WT arrestin-1 to phospho-opsin is comparable to the binding to its preferred target, P-Rh*, suggesting that in photoreceptors arrestin-1 only dissociates after opsin regeneration with 11-cis-retinal, which converts phospho-opsin into inactive phospho-rhodopsin that has lower affinity for arrestin-1. Reduced binding of arrestin-1 to the phospho-opsin form of G90D mutant likely contributes to night blindness caused by this mutation in humans.
Collapse
Affiliation(s)
| | - Martin K. Ostermaier
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Ankita Singhal
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Valerie Panneels
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Kristoff T. Homan
- Life Sciences Institute, Departments of Pharmacology and Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
| | - Alisa Glukhova
- Life Sciences Institute, Departments of Pharmacology and Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
| | - Stephen G. Sligar
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - John J. G. Tesmer
- Life Sciences Institute, Departments of Pharmacology and Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
| | - Gebhard F.X. Schertler
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen 5232, Switzerland
- Department of Biology, ETH Zurich, Zurich, 8093, Switzerland
| | - Joerg Standfuss
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen 5232, Switzerland
| | | |
Collapse
|
42
|
Alexiev U, Farrens DL. Fluorescence spectroscopy of rhodopsins: insights and approaches. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:694-709. [PMID: 24183695 DOI: 10.1016/j.bbabio.2013.10.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/11/2013] [Accepted: 10/16/2013] [Indexed: 01/30/2023]
Abstract
Fluorescence spectroscopy has become an established tool at the interface of biology, chemistry and physics because of its exquisite sensitivity and recent technical advancements. However, rhodopsin proteins present the fluorescence spectroscopist with a unique set of challenges and opportunities due to the presence of the light-sensitive retinal chromophore. This review briefly summarizes some approaches that have successfully met these challenges and the novel insights they have yielded about rhodopsin structure and function. We start with a brief overview of fluorescence fundamentals and experimental methodologies, followed by more specific discussions of technical challenges rhodopsin proteins present to fluorescence studies. Finally, we end by discussing some of the unique insights that have been gained specifically about visual rhodopsin and its interactions with affiliate proteins through the use of fluorescence spectroscopy. This article is part of a Special Issue entitled: Retinal Proteins - You can teach an old dog new tricks.
Collapse
Affiliation(s)
- Ulrike Alexiev
- Physics Department, Freie Universität Berlin, Berlin, Germany.
| | - David L Farrens
- Departments of Biochemistry and Molecular Biology, Oregon Health Sciences University, USA
| |
Collapse
|
43
|
Abstract
Synaptotagmin-1 functions as a Ca(2+) sensor in neurotransmitter release through its two C2 domains (the C2A and C2B domain). The ability of synaptotagmin-1 to bridge two membranes is likely crucial for its function, enabling cooperation with the soluble N-ethylmaleimide sensitive factor adaptor protein receptors (SNAREs) in membrane fusion, but two bridging mechanisms have been proposed. A highly soluble synaptotagmin-1 fragment containing both domains (C2AB) was shown to bind simultaneously to two membranes via the Ca(2+)-binding loops at the top of both domains and basic residues at the bottom of the C2B domain (direct bridging mechanism). In contrast, a longer fragment including a linker sequence (lnC2AB) was found to aggregate in solution and was proposed to bridge membranes through trans interactions between lnC2AB oligomers bound to each membrane via the Ca(2+)-binding loops, with no contact of the bottom of the C2B domain with the membranes. We now show that lnC2AB containing impurities indeed aggregates in solution, but properly purified lnC2AB is highly soluble. Moreover, cryo-EM images reveal that a majority of lnC2AB molecules bridge membranes directly. Fluorescence spectroscopy indicates that the bottom of the C2B domain contacts the membrane in a sizeable population of molecules of both membrane-bound C2AB and membrane-bound lnC2AB. NMR data on nanodiscs show that a fraction of C2AB molecules bind to membranes with antiparallel orientations of the C2 domains. Together with previous studies, these results show that direct bridging constitutes the prevalent mechanism of membrane bridging by both C2AB and lnC2AB, suggesting that this mechanism underlies the function of synaptotagmin-1 in neurotransmitter release.
Collapse
|
44
|
Mary S, Fehrentz JA, Damian M, Gaibelet G, Orcel H, Verdié P, Mouillac B, Martinez J, Marie J, Banères JL. Heterodimerization with Its splice variant blocks the ghrelin receptor 1a in a non-signaling conformation: a study with a purified heterodimer assembled into lipid discs. J Biol Chem 2013; 288:24656-65. [PMID: 23839942 DOI: 10.1074/jbc.m113.453423] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Heterodimerization of G protein-coupled receptors has an impact on their signaling properties, but the molecular mechanisms underlying heteromer-directed selectivity remain elusive. Using purified monomers and dimers reconstituted into lipid discs, we explored how dimerization impacts the functional and structural behavior of the ghrelin receptor. In particular, we investigated how a naturally occurring truncated splice variant of the ghrelin receptor exerts a dominant negative effect on ghrelin signaling upon dimerization with the full-length receptor. We provide direct evidence that this dominant negative effect is due to the ability of the non-signaling truncated receptor to restrict the conformational landscape of the full-length protein. Indeed, associating both proteins within the same disc blocks all agonist- and signaling protein-induced changes in ghrelin receptor conformation, thus preventing it from activating its cognate G protein and triggering arrestin 2 recruitment. This is an unambiguous demonstration that allosteric conformational events within dimeric assemblies can be directly responsible for modulation of signaling mediated by G protein-coupled receptors.
Collapse
Affiliation(s)
- Sophie Mary
- Institut des Biomolécules Max Mousseron (IBMM), CNRS UMR 5247, Université Montpellier 1, Faculté de Pharmacie, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 5, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Huber T, Naganathan S, Tian H, Ye S, Sakmar TP. Unnatural amino acid mutagenesis of GPCRs using amber codon suppression and bioorthogonal labeling. Methods Enzymol 2013; 520:281-305. [PMID: 23332705 DOI: 10.1016/b978-0-12-391861-1.00013-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
To advance dynamic, temporal, and kinetic studies of the G protein-coupled receptor (GPCR) signalosome, new approaches are required to introduce non- or minimally perturbing labels or probes into expressed receptors. We report here a series of methods that are based on unnatural amino acid mutagenesis of GPCRs using amber codon suppression technology. We show that labeling reactions at genetically introduced keto moieties (p-acetyl-L-Phe/AcF and p-benzoyl-L-Phe/BzF) are not completely bioorthogonal due to protein oxidation, which causes high background. However, labeling reactions that target p-azido-L-Phe (azF) using the Staudinger-Bertozzi ligation and the strain-promoted alkyne-azide cycloaddition are bioorthogonal and are satisfactory for introducing labels or probes at near quantitative efficiency under mild labeling conditions. To our knowledge, this is the first report of a site-specific modification of an azF residue with a dibenzocyclooctyne-derivatized fluorophore. The methodologies we discuss are general, in that they can be applied in principle to any amino acid position in any expressed GPCR.
Collapse
Affiliation(s)
- Thomas Huber
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, USA.
| | | | | | | | | |
Collapse
|
46
|
Mörs K, Roos C, Scholz F, Wachtveitl J, Dötsch V, Bernhard F, Glaubitz C. Modified lipid and protein dynamics in nanodiscs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1222-9. [DOI: 10.1016/j.bbamem.2012.12.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/04/2012] [Accepted: 12/11/2012] [Indexed: 02/09/2023]
|
47
|
Mitra N, Liu Y, Liu J, Serebryany E, Mooney V, DeVree BT, Sunahara RK, Yan ECY. Calcium-dependent ligand binding and G-protein signaling of family B GPCR parathyroid hormone 1 receptor purified in nanodiscs. ACS Chem Biol 2013; 8:617-25. [PMID: 23237450 DOI: 10.1021/cb300466n] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
GPCRs mediate intracellular signaling upon external stimuli, making them ideal drug targets. However, little is known about their activation mechanisms due to the difficulty in purification. Here, we introduce a method to purify GPCRs in nanodiscs, which incorporates GPCRs into lipid bilayers immediately after membrane solubilization, followed by single-step purification. Using this approach, we purified a family B GPCR, parathyroid hormone 1 receptor (PTH1R), which regulates calcium and phosphate homeostasis and is a drug target for osteoporosis. We demonstrated that the purified PTH1R in nanodiscs can bind to PTH(1-34) and activate G protein. We also observed that Ca(2+) is a weak agonist of PTH1R, and Ca(2+) in millimolar concentration can switch PTH(1-34) from an inverse agonist to an agonist. Hence, our results show that nanodiscs are a viable vehicle for GPCR purification, enabling studies of GPCRs under precise experimental conditions without interference from other cellular or membrane components.
Collapse
Affiliation(s)
- Nivedita Mitra
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United
States
| | - Yuting Liu
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United
States
| | - Jian Liu
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United
States
| | - Eugene Serebryany
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United
States
| | - Victoria Mooney
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United
States
| | - Brian T. DeVree
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan
48109, United States
| | - Roger K. Sunahara
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan
48109, United States
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United
States
| |
Collapse
|
48
|
|
49
|
Inagaki S, Ghirlando R, Grisshammer R. Biophysical characterization of membrane proteins in nanodiscs. Methods 2013; 59:287-300. [PMID: 23219517 PMCID: PMC3608844 DOI: 10.1016/j.ymeth.2012.11.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/20/2012] [Accepted: 11/23/2012] [Indexed: 12/25/2022] Open
Abstract
Nanodiscs are self-assembled discoidal phospholipid bilayers surrounded and stabilized by membrane scaffold proteins (MSPs), that have become a powerful and promising tool for the study of membrane proteins. Even though their reconstitution is highly regulated by the type of MSP and phospholipid input, a biophysical characterization leading to the determination of the stoichiometry of MSP, lipid and membrane protein is essential. This is important for biological studies, as the oligomeric state of membrane proteins often correlates with their functional activity. Typically combinations of several methods are applied using, for example, modified samples that incorporate fluorescent labels, along with procedures that result in nanodisc disassembly and lipid dissolution. To obtain a comprehensive understanding of the native properties of nanodiscs, modification-free analysis methods are required. In this work we provide a strategy, using a combination of dynamic light scattering and analytical ultracentrifugation, for the biophysical characterization of unmodified nanodiscs. In this manner we characterize the nanodisc preparation in terms of its overall polydispersity and characterize the hydrodynamically resolved nanodisc of interest in terms of its sedimentation coefficient, Stokes' radius and overall protein and lipid stoichiometry. Functional and biological applications are also discussed for the study of the membrane protein embedded in nanodiscs under defined experimental conditions.
Collapse
Affiliation(s)
- Sayaka Inagaki
- Membrane Protein Structure Function Unit, National Institute of Neurological Disorders and Stroke, 5625 Fishers Lane, Room 4S12, Rockville, Maryland 20852, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Building 5, Room 208, 5 Memorial Drive, Bethesda, Maryland, 20814, USA
| | - Reinhard Grisshammer
- Membrane Protein Structure Function Unit, National Institute of Neurological Disorders and Stroke, 5625 Fishers Lane, Room 4S12, Rockville, Maryland 20852, USA
| |
Collapse
|
50
|
Naganathan S, Ye S, Sakmar TP, Huber T. Site-specific epitope tagging of G protein-coupled receptors by bioorthogonal modification of a genetically encoded unnatural amino acid. Biochemistry 2013; 52:1028-36. [PMID: 23317030 DOI: 10.1021/bi301292h] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We developed a general strategy for labeling expressed membrane proteins with a peptide epitope tag and detecting the tagged proteins in native cellular membranes. First, we genetically encoded the unnatural amino acid p-azido-L-phenylalanine (azF) at various specific sites in a G protein-coupled receptor (GPCR), C-C chemokine receptor 5 (CCR5). The reactive azido moiety facilitates Staudinger ligation to a triarylphosphine-conjugated FLAG peptide. We then developed a whole-cell-based enzyme-linked immunosorbent assay approach to detect the modified azF-CCR5 using anti-FLAG mAb. We optimized conditions to achieve labeling and detection of low-abundance GPCRs in live cells. We also performed an accessibility screen to identify azF positions on CCR5 amenable to labeling. Finally, we demonstrate a preparative strategy for obtaining pure bioorthogonally modified GPCRs suitable for single-molecule detection fluorescence experiments. This peptide epitope tagging strategy, which employs genetic encoding and bioorthogonal labeling of azF in live cells, should be useful for studying biogenesis of polytopic membrane proteins and GPCR signaling mechanisms.
Collapse
Affiliation(s)
- Saranga Naganathan
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | | | | | | |
Collapse
|