1
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Podoliak E, Lamm GHU, Marin E, Schellbach AV, Fedotov DA, Stetsenko A, Asido M, Maliar N, Bourenkov G, Balandin T, Baeken C, Astashkin R, Schneider TR, Bateman A, Wachtveitl J, Schapiro I, Busskamp V, Guskov A, Gordeliy V, Alekseev A, Kovalev K. A subgroup of light-driven sodium pumps with an additional Schiff base counterion. Nat Commun 2024; 15:3119. [PMID: 38600129 PMCID: PMC11006869 DOI: 10.1038/s41467-024-47469-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 04/01/2024] [Indexed: 04/12/2024] Open
Abstract
Light-driven sodium pumps (NaRs) are unique ion-transporting microbial rhodopsins. The major group of NaRs is characterized by an NDQ motif and has two aspartic acid residues in the central region essential for sodium transport. Here we identify a subgroup of the NDQ rhodopsins bearing an additional glutamic acid residue in the close vicinity to the retinal Schiff base. We thoroughly characterize a member of this subgroup, namely the protein ErNaR from Erythrobacter sp. HL-111 and show that the additional glutamic acid results in almost complete loss of pH sensitivity for sodium-pumping activity, which is in contrast to previously studied NaRs. ErNaR is capable of transporting sodium efficiently even at acidic pH levels. X-ray crystallography and single particle cryo-electron microscopy reveal that the additional glutamic acid residue mediates the connection between the other two Schiff base counterions and strongly interacts with the aspartic acid of the characteristic NDQ motif. Hence, it reduces its pKa. Our findings shed light on a subgroup of NaRs and might serve as a basis for their rational optimization for optogenetics.
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Affiliation(s)
- E Podoliak
- Department of Ophthalmology, University Hospital Bonn, Medical Faculty, Bonn, Germany
| | - G H U Lamm
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - E Marin
- Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, 9747AG, Groningen, the Netherlands
| | - A V Schellbach
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
- School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, UK
| | - D A Fedotov
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - A Stetsenko
- Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, 9747AG, Groningen, the Netherlands
| | - M Asido
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - N Maliar
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - G Bourenkov
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, 22607, Hamburg, Germany
| | - T Balandin
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
| | - C Baeken
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
| | - R Astashkin
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000, Grenoble, France
| | - T R Schneider
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, 22607, Hamburg, Germany
| | - A Bateman
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, UK
| | - J Wachtveitl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - I Schapiro
- Fritz Haber Center for Molecular Dynamics Research, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - V Busskamp
- Department of Ophthalmology, University Hospital Bonn, Medical Faculty, Bonn, Germany
| | - A Guskov
- Groningen Institute for Biomolecular Sciences and Biotechnology, University of Groningen, 9747AG, Groningen, the Netherlands
| | - V Gordeliy
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000, Grenoble, France
| | - A Alekseev
- University Medical Center Göttingen, Institute for Auditory Neuroscience and InnerEarLab, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
| | - K Kovalev
- European Molecular Biology Laboratory, EMBL Hamburg c/o DESY, 22607, Hamburg, Germany.
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2
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Sineshchekov OA, Govorunova EG, Li H, Wang Y, Spudich JL. Channel Gating in Kalium Channelrhodopsin Slow Mutants. J Mol Biol 2024; 436:168298. [PMID: 37802216 DOI: 10.1016/j.jmb.2023.168298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/14/2023] [Accepted: 09/29/2023] [Indexed: 10/08/2023]
Abstract
Kalium channelrhodopsin 1 from Hyphochytrium catenoides (HcKCR1) is the first discovered natural light-gated ion channel that shows higher selectivity to K+ than to Na+ and therefore is used to silence neurons with light (optogenetics). Replacement of the conserved cysteine residue in the transmembrane helix 3 (Cys110) with alanine or threonine results in a >1,000-fold decrease in the channel closing rate. The phenotype of the corresponding mutants in channelrhodopsin 2 is attributed to breaking of a specific interhelical hydrogen bond (the "DC gate"). Unlike CrChR2 and other ChRs with long distance "DC gates", the HcKCR1 structure does not reveal any hydrogen bonding partners to Cys110, indicating that the mutant phenotype is likely caused by disruption of direct interaction between this residue and the chromophore. In HcKCR1_C110A, fast photochemical conversions corresponding to channel gating were followed by dramatically slower absorption changes. Full recovery of the unphotolyzed state in HcKCR1_C110A was extremely slow with two time constants 5.2 and 70 min. Analysis of the light-minus-dark difference spectra during these slow processes revealed accumulation of at least four spectrally distinct blue light-absorbing photocycle intermediates, L, M1 and M2, and a UV light-absorbing form, typical of bacteriorhodopsin-like channelrhodopsins from cryptophytes. Our results contribute to better understanding of the mechanistic links between the chromophore photochemistry and channel conductance, and provide the basis for using HcKCR1_C110A as an optogenetic tool.
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Affiliation(s)
- Oleg A Sineshchekov
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Elena G Govorunova
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Hai Li
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Yumei Wang
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - John L Spudich
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA.
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3
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Govorunova EG, Sineshchekov OA. Channelrhodopsins: From Phototaxis to Optogenetics. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1555-1570. [PMID: 38105024 DOI: 10.1134/s0006297923100115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 07/09/2023] [Accepted: 07/09/2023] [Indexed: 12/19/2023]
Abstract
Channelrhodopsins stand out among other retinal proteins because of their capacity to generate passive ionic currents following photoactivation. Owing to that, channelrhodopsins are widely used in neuroscience and cardiology as instruments for optogenetic manipulation of the activity of excitable cells. Photocurrents generated by channelrhodopsins were first discovered in the cells of green algae in the 1970s. In this review we describe this discovery and discuss the current state of research in the field.
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4
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Tajima S, Kim YS, Fukuda M, Jo Y, Wang PY, Paggi JM, Inoue M, Byrne EFX, Kishi KE, Nakamura S, Ramakrishnan C, Takaramoto S, Nagata T, Konno M, Sugiura M, Katayama K, Matsui TE, Yamashita K, Kim S, Ikeda H, Kim J, Kandori H, Dror RO, Inoue K, Deisseroth K, Kato HE. Structural basis for ion selectivity in potassium-selective channelrhodopsins. Cell 2023; 186:4325-4344.e26. [PMID: 37652010 PMCID: PMC7615185 DOI: 10.1016/j.cell.2023.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 05/11/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023]
Abstract
KCR channelrhodopsins (K+-selective light-gated ion channels) have received attention as potential inhibitory optogenetic tools but more broadly pose a fundamental mystery regarding how their K+ selectivity is achieved. Here, we present 2.5-2.7 Å cryo-electron microscopy structures of HcKCR1 and HcKCR2 and of a structure-guided mutant with enhanced K+ selectivity. Structural, electrophysiological, computational, spectroscopic, and biochemical analyses reveal a distinctive mechanism for K+ selectivity; rather than forming the symmetrical filter of canonical K+ channels achieving both selectivity and dehydration, instead, three extracellular-vestibule residues within each monomer form a flexible asymmetric selectivity gate, while a distinct dehydration pathway extends intracellularly. Structural comparisons reveal a retinal-binding pocket that induces retinal rotation (accounting for HcKCR1/HcKCR2 spectral differences), and design of corresponding KCR variants with increased K+ selectivity (KALI-1/KALI-2) provides key advantages for optogenetic inhibition in vitro and in vivo. Thus, discovery of a mechanism for ion-channel K+ selectivity also provides a framework for next-generation optogenetics.
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Affiliation(s)
- Seiya Tajima
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Masahiro Fukuda
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - YoungJu Jo
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Peter Y Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Joseph M Paggi
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Masatoshi Inoue
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Eamon F X Byrne
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Koichiro E Kishi
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Seiwa Nakamura
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | | | - Shunki Takaramoto
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Takashi Nagata
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Masae Konno
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Masahiro Sugiura
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Japan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Japan
| | - Toshiki E Matsui
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Keitaro Yamashita
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Suhyang Kim
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Hisako Ikeda
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Jaeah Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Japan
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA; Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA; CNC Program, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
| | - Hideaki E Kato
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan; FOREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan.
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5
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Morizumi T, Kim K, Li H, Govorunova EG, Sineshchekov OA, Wang Y, Zheng L, Bertalan É, Bondar AN, Askari A, Brown LS, Spudich JL, Ernst OP. Structures of channelrhodopsin paralogs in peptidiscs explain their contrasting K + and Na + selectivities. Nat Commun 2023; 14:4365. [PMID: 37474513 PMCID: PMC10359266 DOI: 10.1038/s41467-023-40041-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
Kalium channelrhodopsin 1 from Hyphochytrium catenoides (HcKCR1) is a light-gated channel used for optogenetic silencing of mammalian neurons. It selects K+ over Na+ in the absence of the canonical tetrameric K+ selectivity filter found universally in voltage- and ligand-gated channels. The genome of H. catenoides also encodes a highly homologous cation channelrhodopsin (HcCCR), a Na+ channel with >100-fold larger Na+ to K+ permeability ratio. Here, we use cryo-electron microscopy to determine atomic structures of these two channels embedded in peptidiscs to elucidate structural foundations of their dramatically different cation selectivity. Together with structure-guided mutagenesis, we show that K+ versus Na+ selectivity is determined at two distinct sites on the putative ion conduction pathway: in a patch of critical residues in the intracellular segment (Leu69/Phe69, Ile73/Ser73 and Asp116) and within a cluster of aromatic residues in the extracellular segment (primarily, Trp102 and Tyr222). The two filters are on the opposite sides of the photoactive site involved in channel gating.
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Affiliation(s)
- Takefumi Morizumi
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Kyumhyuk Kim
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Hai Li
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Elena G Govorunova
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Oleg A Sineshchekov
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Yumei Wang
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Lei Zheng
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Éva Bertalan
- Physikzentrum, RWTH-Aachen University, Aachen, Germany
| | - Ana-Nicoleta Bondar
- Faculty of Physics, University of Bucharest, Măgurele, Romania
- Institute of Computational Biomedicine (IAS-5/INM-9), Forschungszentrum Jülich, Jülich, Germany
| | - Azam Askari
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, ON, Canada
| | - Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, ON, Canada
| | - John L Spudich
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA.
| | - Oliver P Ernst
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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6
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Hososhima S, Ueno S, Okado S, Inoue KI, Konno M, Yamauchi Y, Inoue K, Terasaki H, Kandori H, Tsunoda SP. A light-gated cation channel with high reactivity to weak light. Sci Rep 2023; 13:7625. [PMID: 37165048 PMCID: PMC10172181 DOI: 10.1038/s41598-023-34687-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 05/05/2023] [Indexed: 05/12/2023] Open
Abstract
The cryptophyte algae, Guillardia theta, possesses 46 genes that are homologous to microbial rhodopsins. Five of them are functionally light-gated cation channelrhodopsins (GtCCR1-5) that are phylogenetically distinct from chlorophyte channelrhodopsins (ChRs) such as ChR2 from Chlamydomonas reinhardtii. In this study, we report the ion channel properties of these five CCRs and compared them with ChR2 and other ChRs widely used in optogenetics. We revealed that light sensitivity varied among GtCCR1-5, in which GtCCR1-3 exhibited an apparent EC50 of 0.21-1.16 mW/mm2, similar to that of ChR2, whereas GtCCR4 and GtCCR5 possess two EC50s, one of which is significantly small (0.025 and 0.032 mW/mm2). GtCCR4 is able to trigger action potentials in high temporal resolution, similar to ChR2, but requires lower light power, when expressed in cortical neurons. Moreover, a high light-sensitive response was observed when GtCCR4 was introduced into blind retina ganglion cells of rd1, a mouse model of retinitis pigmentosa. Thus, GtCCR4 provides optogenetic neuronal activation with high light sensitivity and temporal precision.
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Affiliation(s)
- Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
- Department of Ophthalmology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan
| | - Satoshi Okado
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Ken-Ichi Inoue
- Primate Research Institute, Kyoto University, Inuyama, Aichi, 484-8506, Japan
| | - Masae Konno
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Yumeka Yamauchi
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan
| | - Keiichi Inoue
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan.
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan.
| | - Satoshi P Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan.
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi, 466-8555, Japan.
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7
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Kojima K, Kawanishi S, Nishimura Y, Hasegawa M, Nakao S, Nagata Y, Yoshizawa S, Sudo Y. A blue-shifted anion channelrhodopsin from the Colpodellida alga Vitrella brassicaformis. Sci Rep 2023; 13:6974. [PMID: 37117398 PMCID: PMC10147648 DOI: 10.1038/s41598-023-34125-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/25/2023] [Indexed: 04/30/2023] Open
Abstract
Microbial rhodopsins, a family of photoreceptive membrane proteins containing the chromophore retinal, show a variety of light-dependent molecular functions. Channelrhodopsins work as light-gated ion channels and are widely utilized for optogenetics, which is a method for controlling neural activities by light. Since two cation channelrhodopsins were identified from the chlorophyte alga Chlamydomonas reinhardtii, recent advances in genomic research have revealed a wide variety of channelrhodopsins including anion channelrhodopsins (ACRs), describing their highly diversified molecular properties (e.g., spectral sensitivity, kinetics and ion selectivity). Here, we report two channelrhodopsin-like rhodopsins from the Colpodellida alga Vitrella brassicaformis, which are phylogenetically distinct from the known channelrhodopsins. Spectroscopic and electrophysiological analyses indicated that these rhodopsins are green- and blue-sensitive pigments (λmax = ~ 550 and ~ 440 nm) that exhibit light-dependent ion channeling activities. Detailed electrophysiological analysis revealed that one of them works as a monovalent anion (Cl-, Br- and NO3-) channel and we named it V. brassicaformis anion channelrhodopsin-2, VbACR2. Importantly, the absorption maximum of VbACR2 (~ 440 nm) is blue-shifted among the known ACRs. Thus, we identified the new blue-shifted ACR, which leads to the expansion of the molecular diversity of ACRs.
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Affiliation(s)
- Keiichi Kojima
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.
| | - Shiho Kawanishi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Yosuke Nishimura
- Research Center for Bioscience and Nanoscience (CeBN), Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kanagawa, 237-0061, Japan
| | - Masumi Hasegawa
- Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-Star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kanagawa, 237-0061, Japan
| | - Shin Nakao
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Yuya Nagata
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Susumu Yoshizawa
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, 277-8564, Japan
| | - Yuki Sudo
- Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.
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8
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Kishi KE, Kato HE. Pump-like channelrhodopsins: Not just bridging the gap between ion pumps and ion channels. Curr Opin Struct Biol 2023; 79:102562. [PMID: 36871323 DOI: 10.1016/j.sbi.2023.102562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 01/25/2023] [Accepted: 01/29/2023] [Indexed: 03/06/2023]
Abstract
Channelrhodopsins are microbial rhodopsins that work as light-gated ion channels. Their importance has become increasingly recognized due to their ability to control the membrane potential of specific cells in a light-dependent manner. This technology, termed optogenetics, has revolutionized neuroscience, and numerous channelrhodopsin variants have been isolated or engineered to expand the utility of optogenetics. Pump-like channelrhodopsins (PLCRs), one of the recently discovered channelrhodopsin subfamilies, have attracted broad attention due to their high sequence similarity to ion-pumping rhodopsins and their distinct properties, such as high light sensitivity and ion selectivity. In this review, we summarize the current understanding of the structure-function relationships of PLCRs and discuss the challenges and opportunities of channelrhodopsin research.
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Affiliation(s)
- Koichiro E Kishi
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan. https://twitter.com/K_E_Kishi
| | - Hideaki E Kato
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan; FOREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan.
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9
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Govorunova EG, Sineshchekov OA, Spudich JL. Potassium-selective channelrhodopsins. Biophys Physicobiol 2023; 20:e201011. [PMID: 38362336 PMCID: PMC10865875 DOI: 10.2142/biophysico.bppb-v20.s011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/03/2023] [Indexed: 02/05/2023] Open
Abstract
Since their discovery 21 years ago, channelrhodopsins have come of age and have become indispensable tools for optogenetic control of excitable cells such as neurons and myocytes. Potential therapeutic utility of channelrhodopsins has been proven by partial vision restoration in a human patient. Previously known channelrhodopsins are either proton channels, non-selective cation channels almost equally permeable to Na+ and K+ besides protons, or anion channels. Two years ago, we discovered a group of channelrhodopsins that exhibit over an order of magnitude higher selectivity for K+ than for Na+. These proteins, known as "kalium channelrhodopsins" or KCRs, lack the canonical tetrameric selectivity filter found in voltage- and ligand-gated K+ channels, and use a unique selectivity mechanism intrinsic to their individual protomers. Mutant analysis has revealed that the key residues responsible for K+ selectivity in KCRs are located at both ends of the putative cation conduction pathway, and their role has been confirmed by high-resolution KCR structures. Expression of KCRs in mouse neurons and human cardiomyocytes enabled optical inhibition of these cells' electrical activity. In this minireview we briefly discuss major results of KCR research obtained during the last two years and suggest some directions of future research.
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Affiliation(s)
- Elena G. Govorunova
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
| | - Oleg A. Sineshchekov
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
| | - John L. Spudich
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, Houston, TX 77030, USA
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10
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van Stokkum IH, Hontani Y, Vierock J, Krause BS, Hegemann P, Kennis JT. Reaction Dynamics in the Chrimson Channelrhodopsin: Observation of Product-State Evolution and Slow Diffusive Protein Motions. J Phys Chem Lett 2023; 14:1485-1493. [PMID: 36745035 PMCID: PMC9940203 DOI: 10.1021/acs.jpclett.2c03110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Chrimson is a red-light absorbing channelrhodopsin useful for deep-tissue optogenetics applications. Here, we present the Chrimson reaction dynamics from femtoseconds to seconds, analyzed with target analysis methods to disentangle spectrally and temporally overlapping excited- and product-state dynamics. We found multiple phases ranging from ≈100 fs to ≈20 ps in the excited-state decay, where spectral features overlapping with stimulated emission components were assigned to early dynamics of K-like species on a 10 ps time scale. Selective excitation at the maximum or the blue edge of the absorption spectrum resulted in spectrally distinct but kinetically similar excited-state and product-state species, which gradually became indistinguishable on the μs to 100 μs time scales. Hence, by removing specific protein conformations within an inhomogeneously broadened ensemble, we resolved slow protein backbone and amino acid side-chain motions in the dark that underlie inhomogeneous broadening, demonstrating that the latter represents a dynamic interconversion between protein substates.
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Affiliation(s)
- Ivo H.M. van Stokkum
- Department
of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HVAmsterdam, The Netherlands
| | - Yusaku Hontani
- Department
of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HVAmsterdam, The Netherlands
| | - Johannes Vierock
- Institut
für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115Berlin, Germany
| | - Benjamin S. Krause
- Institut
für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115Berlin, Germany
| | - Peter Hegemann
- Institut
für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115Berlin, Germany
| | - John T.M. Kennis
- Department
of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HVAmsterdam, The Netherlands
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11
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Abstract
Potassium-selective channelrhodopsins (KCRs) are light-gated K+ channels recently found in the stramenopile protist Hyphochytrium catenoides. When expressed in neurons, KCRs enable high-precision optical inhibition of spiking (optogenetic silencing). KCRs are capable of discriminating K+ from Na+ without the conventional K+ selectivity filter found in classical K+ channels. The genome of H. catenoides also encodes a third paralog that is more permeable for Na+ than for K+. To identify structural motifs responsible for the unusual K+ selectivity of KCRs, we systematically analyzed a series of chimeras and mutants of this protein. We found that mutations of three critical residues in the paralog convert its Na+-selective channel into a K+-selective one. Our characterization of homologous proteins from other protists (Colponema vietnamica, Cafeteria burkhardae, and Chromera velia) and metagenomic samples confirmed the importance of these residues for K+ selectivity. We also show that Trp102 and Asp116, conserved in all three H. catenoides paralogs, are necessary, although not sufficient, for K+ selectivity. Our results provide the foundation for further engineering of KCRs for optogenetic needs. IMPORTANCE Recently discovered microbial light-gated ion channels (channelrhodopsins) with a higher permeability for K+ than for Na+ (potassium-selective channelrhodopsins [kalium channelrhodopsins, or KCRs]) demonstrate an alternative K+ selectivity mechanism, unrelated to well-characterized "selectivity filters" of voltage- and ligand-gated K+ channels. KCRs can be used for optogenetic inhibition of neuronal firing and potentially for the development of gene therapies to treat neurological and cardiovascular disorders. In this study, we identified structural motifs that determine the K+ selectivity of KCRs that provide the foundation for their further improvement as optogenetic tools.
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12
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Vierock J, Peter E, Grimm C, Rozenberg A, Chen IW, Tillert L, Castro Scalise AG, Casini M, Augustin S, Tanese D, Forget BC, Peyronnet R, Schneider-Warme F, Emiliani V, Béjà O, Hegemann P. WiChR, a highly potassium-selective channelrhodopsin for low-light one- and two-photon inhibition of excitable cells. SCIENCE ADVANCES 2022; 8:eadd7729. [PMID: 36383037 PMCID: PMC9733931 DOI: 10.1126/sciadv.add7729] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 10/28/2022] [Indexed: 05/30/2023]
Abstract
The electric excitability of muscle, heart, and brain tissue relies on the precise interplay of Na+- and K+-selective ion channels. The involved ion fluxes are controlled in optogenetic studies using light-gated channelrhodopsins (ChRs). While non-selective cation-conducting ChRs are well established for excitation, K+-selective ChRs (KCRs) for efficient inhibition have only recently come into reach. Here, we report the molecular analysis of recently discovered KCRs from the stramenopile Hyphochytrium catenoides and identification of a novel type of hydrophobic K+ selectivity filter. Next, we demonstrate that the KCR signature motif is conserved in related stramenopile ChRs. Among them, WiChR from Wobblia lunata features a so far unmatched preference for K+ over Na+, stable photocurrents under continuous illumination, and a prolonged open-state lifetime. Showing high expression levels in cardiac myocytes and neurons, WiChR allows single- and two-photon inhibition at low irradiance and reduced tissue heating. Therefore, we recommend WiChR as the long-awaited efficient and versatile optogenetic inhibitor.
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Affiliation(s)
- Johannes Vierock
- Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
- Neuroscience Research Center, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Enrico Peter
- Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Christiane Grimm
- Wavefront Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Andrey Rozenberg
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa 32000, Israel
| | - I-Wen Chen
- Wavefront Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Linda Tillert
- Neuroscience Research Center, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | | | - Marilù Casini
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg · Bad Krozingen, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- Regenerative Medicine and Heart Transplantation Unit, Instituto de Investigación Sanitaria La Fe and ITACA Institute (COR), Universitat Politècnica de València, Valencia, Spain
| | - Sandra Augustin
- Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dimitrii Tanese
- Wavefront Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Benoît C. Forget
- Wavefront Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg · Bad Krozingen, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Franziska Schneider-Warme
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg · Bad Krozingen, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Valentina Emiliani
- Wavefront Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Oded Béjà
- Faculty of Biology, Technion–Israel Institute of Technology, Haifa 32000, Israel
| | - Peter Hegemann
- Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
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13
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Hososhima S, Mizutori R, Abe-Yoshizumi R, Rozenberg A, Shigemura S, Pushkarev A, Konno M, Katayama K, Inoue K, Tsunoda SP, Béjà O, Kandori H. Proton-transporting heliorhodopsins from marine giant viruses. eLife 2022; 11:78416. [PMID: 36065640 PMCID: PMC9448325 DOI: 10.7554/elife.78416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 08/07/2022] [Indexed: 12/02/2022] Open
Abstract
Rhodopsins convert light into signals and energy in animals and microbes. Heliorhodopsins (HeRs), a recently discovered new rhodopsin family, are widely present in archaea, bacteria, unicellular eukaryotes, and giant viruses, but their function remains unknown. Here, we report that a viral HeR from Emiliania huxleyi virus 202 (V2HeR3) is a light-activated proton transporter. V2HeR3 absorbs blue-green light, and the active intermediate contains the deprotonated retinal Schiff base. Site-directed mutagenesis study revealed that E191 in TM6 constitutes the gate together with the retinal Schiff base. E205 and E215 form a PAG of the Schiff base, and mutations at these positions converted the protein into an outward proton pump. Three environmental viral HeRs from the same group as well as a more distantly related HeR exhibited similar proton-transport activity, indicating that HeR functions might be diverse similarly to type-1 microbial rhodopsins. Some strains of E. huxleyi contain one HeR that is related to the viral HeRs, while its viruses EhV-201 and EhV-202 contain two and three HeRs, respectively. Except for V2HeR3 from EhV-202, none of these proteins exhibit ion transport activity. Thus, when expressed in the E. huxleyi cell membranes, only V2HeR3 has the potential to depolarize the host cells by light, possibly to overcome the host defense mechanisms or to prevent superinfection. The neuronal activity generated by V2HeR3 suggests that it can potentially be used as an optogenetic tool, similarly to type-1 microbial rhodopsins.
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Affiliation(s)
- Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
| | - Ritsu Mizutori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
| | - Rei Abe-Yoshizumi
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
| | | | - Shunta Shigemura
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
| | | | - Masae Konno
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
- OptoBioTechnology Research Center, Nagoya Institute of Technology
| | - Keiichi Inoue
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
| | - Satoshi P Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
- OptoBioTechnology Research Center, Nagoya Institute of Technology
| | - Oded Béjà
- Faculty of Biology, Technion-Israel Institute of Technology
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology
- OptoBioTechnology Research Center, Nagoya Institute of Technology
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14
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Tucker K, Sridharan S, Adesnik H, Brohawn SG. Cryo-EM structures of the channelrhodopsin ChRmine in lipid nanodiscs. Nat Commun 2022; 13:4842. [PMID: 35977941 PMCID: PMC9385719 DOI: 10.1038/s41467-022-32441-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 08/01/2022] [Indexed: 12/03/2022] Open
Abstract
Microbial channelrhodopsins are light-gated ion channels widely used for optogenetic manipulation of neuronal activity. ChRmine is a bacteriorhodopsin-like cation channelrhodopsin (BCCR) more closely related to ion pump rhodopsins than other channelrhodopsins. ChRmine displays unique properties favorable for optogenetics including high light sensitivity, a broad, red-shifted activation spectrum, cation selectivity, and large photocurrents, while its slow closing kinetics impedes some applications. The structural basis for ChRmine function, or that of any other BCCR, is unknown. Here, we present cryo-EM structures of ChRmine in lipid nanodiscs in apo (opsin) and retinal-bound (rhodopsin) forms. The structures reveal an unprecedented trimeric architecture with a lipid filled central pore. Large electronegative cavities on either side of the membrane facilitate high conductance and selectivity for cations over protons. The retinal binding pocket structure suggests channel properties could be tuned with mutations and we identify ChRmine variants with ten-fold decreased and two-fold increased closing rates. A T119A mutant shows favorable properties relative to wild-type and previously reported ChRmine variants for optogenetics. These results provide insight into structural features that generate an ultra-potent microbial opsin and provide a platform for rational engineering of channelrhodopsins with improved properties that could expand the scale, depth, and precision of optogenetic experiments.
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Affiliation(s)
- Kyle Tucker
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, 94720, USA
| | - Savitha Sridharan
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Hillel Adesnik
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA.
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA.
| | - Stephen G Brohawn
- Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, CA, 94720, USA.
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA.
- California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, 94720, USA.
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15
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Emiliani V, Entcheva E, Hedrich R, Hegemann P, Konrad KR, Lüscher C, Mahn M, Pan ZH, Sims RR, Vierock J, Yizhar O. Optogenetics for light control of biological systems. NATURE REVIEWS. METHODS PRIMERS 2022; 2:55. [PMID: 37933248 PMCID: PMC10627578 DOI: 10.1038/s43586-022-00136-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/30/2022] [Indexed: 11/08/2023]
Abstract
Optogenetic techniques have been developed to allow control over the activity of selected cells within a highly heterogeneous tissue, using a combination of genetic engineering and light. Optogenetics employs natural and engineered photoreceptors, mostly of microbial origin, to be genetically introduced into the cells of interest. As a result, cells that are naturally light-insensitive can be made photosensitive and addressable by illumination and precisely controllable in time and space. The selectivity of expression and subcellular targeting in the host is enabled by applying control elements such as promoters, enhancers and specific targeting sequences to the employed photoreceptor-encoding DNA. This powerful approach allows precise characterization and manipulation of cellular functions and has motivated the development of advanced optical methods for patterned photostimulation. Optogenetics has revolutionized neuroscience during the past 15 years and is primed to have a similar impact in other fields, including cardiology, cell biology and plant sciences. In this Primer, we describe the principles of optogenetics, review the most commonly used optogenetic tools, illumination approaches and scientific applications and discuss the possibilities and limitations associated with optogenetic manipulations across a wide variety of optical techniques, cells, circuits and organisms.
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Affiliation(s)
- Valentina Emiliani
- Wavefront Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Emilia Entcheva
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | - Rainer Hedrich
- Julius-von-Sachs Institute for Biosciences, Molecular Plant Physiology and Biophysics, University of Wuerzburg, Wuerzburg, Germany
| | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt-Universitaet zu Berlin, Berlin, Germany
| | - Kai R. Konrad
- Julius-von-Sachs Institute for Biosciences, Molecular Plant Physiology and Biophysics, University of Wuerzburg, Wuerzburg, Germany
| | - Christian Lüscher
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Clinic of Neurology, Department of Clinical Neurosciences, Geneva University Hospital, Geneva, Switzerland
| | - Mathias Mahn
- Department of Neurobiology, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Zhuo-Hua Pan
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, USA
| | - Ruth R. Sims
- Wavefront Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Johannes Vierock
- Institute for Biology, Experimental Biophysics, Humboldt-Universitaet zu Berlin, Berlin, Germany
- Neuroscience Research Center, Charité – Universitaetsmedizin Berlin, Berlin, Germany
| | - Ofer Yizhar
- Departments of Brain Sciences and Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
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16
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Govorunova EG, Gou Y, Sineshchekov OA, Li H, Lu X, Wang Y, Brown LS, St-Pierre F, Xue M, Spudich JL. Kalium channelrhodopsins are natural light-gated potassium channels that mediate optogenetic inhibition. Nat Neurosci 2022; 25:967-974. [PMID: 35726059 PMCID: PMC9854242 DOI: 10.1038/s41593-022-01094-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 05/12/2022] [Indexed: 02/02/2023]
Abstract
Channelrhodopsins are used widely for optical control of neurons, in which they generate photoinduced proton, sodium or chloride influx. Potassium (K+) is central to neuron electrophysiology, yet no natural K+-selective light-gated channel has been identified. Here, we report kalium channelrhodopsins (KCRs) from Hyphochytrium catenoides. Previously known gated potassium channels are mainly ligand- or voltage-gated and share a conserved K+-selectivity filter. KCRs differ in that they are light-gated and have independently evolved an alternative K+ selectivity mechanism. The KCRs are potent, highly selective of K+ over Na+, and open in less than 1 ms following photoactivation. The permeability ratio PK/PNa of 23 makes H. catenoides KCR1 (HcKCR1) a powerful hyperpolarizing tool to suppress excitable cell firing upon illumination, demonstrated here in mouse cortical neurons. HcKCR1 enables optogenetic control of K+ gradients, which is promising for the study and potential treatment of potassium channelopathies such as epilepsy, Parkinson's disease and long-QT syndrome and other cardiac arrhythmias.
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Affiliation(s)
- Elena G Govorunova
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Yueyang Gou
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Oleg A Sineshchekov
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Hai Li
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Xiaoyu Lu
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA
| | - Yumei Wang
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada
| | - François St-Pierre
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Mingshan Xue
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - John L Spudich
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA.
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17
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Brown LS. Light-driven proton transfers and proton transport by microbial rhodopsins - A biophysical perspective. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183867. [PMID: 35051382 DOI: 10.1016/j.bbamem.2022.183867] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/30/2021] [Accepted: 01/10/2022] [Indexed: 12/31/2022]
Abstract
In the last twenty years, our understanding of the rules and mechanisms for the outward light-driven proton transport (and underlying proton transfers) by microbial rhodopsins has been changing dramatically. It transitioned from a very detailed atomic-level understanding of proton transport by bacteriorhodopsin, the prototypical proton pump, to a confounding variety of sequence motifs, mechanisms, directions, and modes of transport in its newly found homologs. In this review, we will summarize and discuss experimental data obtained on new microbial rhodopsin variants, highlighting their contribution to the refinement and generalization of the ideas crystallized in the previous century. In particular, we will focus on the proton transport (and transfers) vectoriality and their structural determinants, which, in many cases, remain unidentified.
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Affiliation(s)
- Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Ontario N1G 2W1, Canada.
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18
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Kishi KE, Kim YS, Fukuda M, Inoue M, Kusakizako T, Wang PY, Ramakrishnan C, Byrne EFX, Thadhani E, Paggi JM, Matsui TE, Yamashita K, Nagata T, Konno M, Quirin S, Lo M, Benster T, Uemura T, Liu K, Shibata M, Nomura N, Iwata S, Nureki O, Dror RO, Inoue K, Deisseroth K, Kato HE. Structural basis for channel conduction in the pump-like channelrhodopsin ChRmine. Cell 2022; 185:672-689.e23. [PMID: 35114111 PMCID: PMC7612760 DOI: 10.1016/j.cell.2022.01.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/13/2021] [Accepted: 01/11/2022] [Indexed: 12/24/2022]
Abstract
ChRmine, a recently discovered pump-like cation-conducting channelrhodopsin, exhibits puzzling properties (large photocurrents, red-shifted spectrum, and extreme light sensitivity) that have created new opportunities in optogenetics. ChRmine and its homologs function as ion channels but, by primary sequence, more closely resemble ion pump rhodopsins; mechanisms for passive channel conduction in this family have remained mysterious. Here, we present the 2.0 Å resolution cryo-EM structure of ChRmine, revealing architectural features atypical for channelrhodopsins: trimeric assembly, a short transmembrane-helix 3, a twisting extracellular-loop 1, large vestibules within the monomer, and an opening at the trimer interface. We applied this structure to design three proteins (rsChRmine and hsChRmine, conferring further red-shifted and high-speed properties, respectively, and frChRmine, combining faster and more red-shifted performance) suitable for fundamental neuroscience opportunities. These results illuminate the conduction and gating of pump-like channelrhodopsins and point the way toward further structure-guided creation of channelrhodopsins for applications across biology.
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Affiliation(s)
- Koichiro E Kishi
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Masahiro Fukuda
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Masatoshi Inoue
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Peter Y Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | | | - Eamon F X Byrne
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Elina Thadhani
- Department of Bioengineering, Stanford University, Stanford, CA, USA; Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Joseph M Paggi
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Toshiki E Matsui
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan
| | - Keitaro Yamashita
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Takashi Nagata
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Masae Konno
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Sean Quirin
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Maisie Lo
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tyler Benster
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Tomoko Uemura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - Kehong Liu
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - Mikihiro Shibata
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma, Kanazawa, Japan; High-Speed AFM for Biological Application Unit, Institute for Frontier Science Initiative, Kanazawa University, Kakuma, Kanazawa, Japan
| | - Norimichi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan
| | - So Iwata
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Sakyo, Japan; RIKEN SPring-8 Center, Kouto, Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA; Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Keiichi Inoue
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA; CNC Program, Stanford University, Palo Alto, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA; Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
| | - Hideaki E Kato
- Komaba Institute for Science, The University of Tokyo, Meguro, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan; FOREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan.
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19
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Govorunova EG, Sineshchekov OA, Spudich JL. Emerging Diversity of Channelrhodopsins and Their Structure-Function Relationships. Front Cell Neurosci 2022; 15:800313. [PMID: 35140589 PMCID: PMC8818676 DOI: 10.3389/fncel.2021.800313] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/28/2021] [Indexed: 12/12/2022] Open
Abstract
Cation and anion channelrhodopsins (CCRs and ACRs, respectively) from phototactic algae have become widely used as genetically encoded molecular tools to control cell membrane potential with light. Recent advances in polynucleotide sequencing, especially in environmental samples, have led to identification of hundreds of channelrhodopsin homologs in many phylogenetic lineages, including non-photosynthetic protists. Only a few CCRs and ACRs have been characterized in detail, but there are indications that ion channel function has evolved within the rhodopsin superfamily by convergent routes. The diversity of channelrhodopsins provides an exceptional platform for the study of structure-function evolution in membrane proteins. Here we review the current state of channelrhodopsin research and outline perspectives for its further development.
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20
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Abstract
Optogenetics has revolutionized not only neuroscience but also had an impact on muscle physiology and cell biology. Rhodopsin-based optogenetics started with the discovery of the light-gated cation channels, called channelrhodopsins. Together with the light-driven ion pumps, these channels allow light-mediated control of electrically excitable cells in culture tissue and living animals. They can be activated (depolarized) or silenced (hyperpolarized) by light with incomparably high spatiotemporal resolution. Optogenetics allows the light manipulation of cells under electrode-free conditions in a minimally invasive manner. Through modern genetic techniques, virus-induced transduction can be performed with extremely high cell specificity in tissue and living animals, allowing completely new approaches for analyzing neural networks, behavior studies, and investigations of neurodegenerative diseases. First clinical trials for the optogenetic recovery of vision are underway.This chapter provides a comprehensive description of the structure and function of the different light-gated channels and some new light-activated ion pumps. Some of them already play an essential role in optogenetics while others are supposed to become important tools for more specialized applications in the future.At the moment, a large number of publications are available concerning intrinsic mechanisms of microbial rhodopsins. Mostly they describe CrChR2 and its variants, as CrChR2 is still the most prominent optogenetic tool. Therefore, many biophysically and biochemically oriented groups contributed to the overwhelming mass of information on this unique ion channel's molecular mechanism. In this context, the function of new optogenetic tools is discussed, which is essential for rational optimization of the optogenetic approach for an eventual biomedical application. The comparison of the effectivity of ion pumps versus ion channels is discussed as well.Applications of rhodopsins-based optogenetic tools are also discussed in the chapter. Because of the enormous number of these applications in neuroscience, only exemplary studies on cell culture neural tissue, muscle physiology, and remote control of animal behavior are presented.
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Affiliation(s)
- Alexey Alekseev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Valentin Gordeliy
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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21
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Timsit Y, Grégoire SP. Towards the Idea of Molecular Brains. Int J Mol Sci 2021; 22:ijms222111868. [PMID: 34769300 PMCID: PMC8584932 DOI: 10.3390/ijms222111868] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
How can single cells without nervous systems perform complex behaviours such as habituation, associative learning and decision making, which are considered the hallmark of animals with a brain? Are there molecular systems that underlie cognitive properties equivalent to those of the brain? This review follows the development of the idea of molecular brains from Darwin’s “root brain hypothesis”, through bacterial chemotaxis, to the recent discovery of neuron-like r-protein networks in the ribosome. By combining a structural biology view with a Bayesian brain approach, this review explores the evolutionary labyrinth of information processing systems across scales. Ribosomal protein networks open a window into what were probably the earliest signalling systems to emerge before the radiation of the three kingdoms. While ribosomal networks are characterised by long-lasting interactions between their protein nodes, cell signalling networks are essentially based on transient interactions. As a corollary, while signals propagated in persistent networks may be ephemeral, networks whose interactions are transient constrain signals diffusing into the cytoplasm to be durable in time, such as post-translational modifications of proteins or second messenger synthesis. The duration and nature of the signals, in turn, implies different mechanisms for the integration of multiple signals and decision making. Evolution then reinvented networks with persistent interactions with the development of nervous systems in metazoans. Ribosomal protein networks and simple nervous systems display architectural and functional analogies whose comparison could suggest scale invariance in information processing. At the molecular level, the significant complexification of eukaryotic ribosomal protein networks is associated with a burst in the acquisition of new conserved aromatic amino acids. Knowing that aromatic residues play a critical role in allosteric receptors and channels, this observation suggests a general role of π systems and their interactions with charged amino acids in multiple signal integration and information processing. We think that these findings may provide the molecular basis for designing future computers with organic processors.
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Affiliation(s)
- Youri Timsit
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, 3 rue Michel-Ange, 75016 Paris, France
- Correspondence:
| | - Sergeant-Perthuis Grégoire
- Institut de Mathématiques de Jussieu—Paris Rive Gauche (IMJ-PRG), UMR 7586, CNRS-Université Paris Diderot, 75013 Paris, France;
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22
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Bioluminescence and Photoreception in Unicellular Organisms: Light-Signalling in a Bio-Communication Perspective. Int J Mol Sci 2021; 22:ijms222111311. [PMID: 34768741 PMCID: PMC8582858 DOI: 10.3390/ijms222111311] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 12/13/2022] Open
Abstract
Bioluminescence, the emission of light catalysed by luciferases, has evolved in many taxa from bacteria to vertebrates and is predominant in the marine environment. It is now well established that in animals possessing a nervous system capable of integrating light stimuli, bioluminescence triggers various behavioural responses and plays a role in intra- or interspecific visual communication. The function of light emission in unicellular organisms is less clear and it is currently thought that it has evolved in an ecological framework, to be perceived by visual animals. For example, while it is thought that bioluminescence allows bacteria to be ingested by zooplankton or fish, providing them with favourable conditions for growth and dispersal, the luminous flashes emitted by dinoflagellates may have evolved as an anti-predation system against copepods. In this short review, we re-examine this paradigm in light of recent findings in microorganism photoreception, signal integration and complex behaviours. Numerous studies show that on the one hand, bacteria and protists, whether autotrophs or heterotrophs, possess a variety of photoreceptors capable of perceiving and integrating light stimuli of different wavelengths. Single-cell light-perception produces responses ranging from phototaxis to more complex behaviours. On the other hand, there is growing evidence that unicellular prokaryotes and eukaryotes can perform complex tasks ranging from habituation and decision-making to associative learning, despite lacking a nervous system. Here, we focus our analysis on two taxa, bacteria and dinoflagellates, whose bioluminescence is well studied. We propose the hypothesis that similar to visual animals, the interplay between light-emission and reception could play multiple roles in intra- and interspecific communication and participate in complex behaviour in the unicellular world.
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23
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Rokitskaya TI, Maliar N, Kovalev KV, Volkov O, Gordeliy VI, Antonenko YN. Rhodopsin Channel Activity Can Be Evaluated by Measuring the Photocurrent Voltage Dependence in Planar Bilayer Lipid Membranes. BIOCHEMISTRY (MOSCOW) 2021; 86:409-419. [PMID: 33941063 DOI: 10.1134/s0006297921040039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The studies of the functional properties of retinal-containing proteins often include experiments in model membrane systems, e.g., measurements of electric current through planar bilayer lipid membranes (BLMs) with proteoliposomes adsorbed on one of the membrane surfaces. However, the possibilities of this method have not been fully explored yet. We demonstrated that the voltage dependence of stationary photocurrents for two light-sensitive proteins, bacteriorhodopsin (bR) and channelrhodopsin 2 (ChR2), in the presence of protonophore had very different characteristics. In the case of the bR (proton pump), the photocurrent through the BLM did not change direction when the polarity of the applied voltage was switched. In the case of the photosensitive channel protein ChR2, the photocurrent increased with the increase in voltage and the current polarity changed with the change in the voltage polarity. The protonophore 4,5,6,7-tetrachloro-2-trifluoromethyl benzimidazole (TTFB) was more efficient in the maximizing stationary photocurrents. In the presence of carbonyl cyanide-m-chlorophenylhydrazone (CCCP), the amplitude of the measured photocurrents for bR significantly decreased, while in the case of ChR2, the photocurrents virtually disappeared. The difference between the effects of TTFB and CCCP was apparently due to the fact that, in contrast to TTFB, CCCP transfers protons across the liposome membranes with a higher rate than through the decane-containing BLM used as a surface for the proteoliposome adsorption.
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Affiliation(s)
- Tatyana I Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
| | - Nina Maliar
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Kirill V Kovalev
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia.,Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, 38044, France
| | - Oleksandr Volkov
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Juelich, 52425, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Juelich, 52425, Germany
| | - Valentin I Gordeliy
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia.,Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, 38044, France.,Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Juelich, 52425, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Juelich, 52425, Germany
| | - Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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24
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Zabelskii D, Alekseev A, Kovalev K, Rankovic V, Balandin T, Soloviov D, Bratanov D, Savelyeva E, Podolyak E, Volkov D, Vaganova S, Astashkin R, Chizhov I, Yutin N, Rulev M, Popov A, Eria-Oliveira AS, Rokitskaya T, Mager T, Antonenko Y, Rosselli R, Armeev G, Shaitan K, Vivaudou M, Büldt G, Rogachev A, Rodriguez-Valera F, Kirpichnikov M, Moser T, Offenhäusser A, Willbold D, Koonin E, Bamberg E, Gordeliy V. Viral rhodopsins 1 are an unique family of light-gated cation channels. Nat Commun 2020; 11:5707. [PMID: 33177509 PMCID: PMC7659345 DOI: 10.1038/s41467-020-19457-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/07/2020] [Indexed: 11/09/2022] Open
Abstract
Phytoplankton is the base of the marine food chain as well as oxygen and carbon cycles and thus plays a global role in climate and ecology. Nucleocytoplasmic Large DNA Viruses that infect phytoplankton organisms and regulate the phytoplankton dynamics encompass genes of rhodopsins of two distinct families. Here, we present a functional and structural characterization of two proteins of viral rhodopsin group 1, OLPVR1 and VirChR1. Functional analysis of VirChR1 shows that it is a highly selective, Na+/K+-conducting channel and, in contrast to known cation channelrhodopsins, it is impermeable to Ca2+ ions. We show that, upon illumination, VirChR1 is able to drive neural firing. The 1.4 Å resolution structure of OLPVR1 reveals remarkable differences from the known channelrhodopsins and a unique ion-conducting pathway. Thus, viral rhodopsins 1 represent a unique, large group of light-gated channels (viral channelrhodopsins, VirChR1s). In nature, VirChR1s likely mediate phototaxis of algae enhancing the host anabolic processes to support virus reproduction, and therefore, might play a major role in global phytoplankton dynamics. Moreover, VirChR1s have unique potential for optogenetics as they lack possibly noxious Ca2+ permeability. Nucleocytoplasmic Large DNA Viruses (NCLDV) that infect algae encode two distinct families of microbial rhodopsins. Here, the authors characterise two proteins form the viral rhodopsin group 1 OLPVR1 and VirChR1, present the 1.4 Å crystal structure of OLPVR1 and show that viral rhodopsins 1 are light-gated cation channels.
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Affiliation(s)
- Dmitrii Zabelskii
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Alexey Alekseev
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Institute of Crystallography, University of Aachen (RWTH), Aachen, Germany
| | - Kirill Kovalev
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Institute of Crystallography, University of Aachen (RWTH), Aachen, Germany.,Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Vladan Rankovic
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany
| | - Taras Balandin
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Dmytro Soloviov
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Joint Institute for Nuclear Research, Dubna, Russia.,Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, Kyiv, 03680, Ukraine
| | - Dmitry Bratanov
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Ekaterina Savelyeva
- Institute of Biological Information Processing (IBI-3: Bioelectronics), Forschungszentrum Jülich GmbH, Jülich, Germany.,Laboratory of Functional Materials and Devices for Nanoelectronics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Center of Shared Research Facilities, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Elizaveta Podolyak
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Dmytro Volkov
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Svetlana Vaganova
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Roman Astashkin
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Igor Chizhov
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Natalia Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Maksim Rulev
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany.,European Synchrotron Radiation Facility, Grenoble, France
| | | | - Ana-Sofia Eria-Oliveira
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Tatiana Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Thomas Mager
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Yuri Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Riccardo Rosselli
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Spain.,Department of Marine Microbiology and Biogeochemistry, Royal Netherland Institute for Sea Research (NIOZ), and Utrecht University, Den Burg, The Netherlands
| | - Grigoriy Armeev
- Biological Faculty, M. V. Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Konstantin Shaitan
- Biological Faculty, M. V. Lomonosov Moscow State University, Moscow, 119991, Russia.,N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Michel Vivaudou
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France.,Laboratories of Excellence, Ion Channel Science and Therapeutics, 06560, Valbonne, France
| | - Georg Büldt
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Andrey Rogachev
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Joint Institute for Nuclear Research, Dubna, Russia
| | - Francisco Rodriguez-Valera
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Spain
| | - Mikhail Kirpichnikov
- Biological Faculty, M. V. Lomonosov Moscow State University, Moscow, 119991, Russia.,M. M. Shemyakin-Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Andreas Offenhäusser
- Institute of Biological Information Processing (IBI-3: Bioelectronics), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Dieter Willbold
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Institut für Physikalische Biologie, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Eugene Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Ernst Bamberg
- Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Valentin Gordeliy
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany. .,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany. .,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia. .,Institute of Crystallography, University of Aachen (RWTH), Aachen, Germany. .,Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France.
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25
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RubyACRs, nonalgal anion channelrhodopsins with highly red-shifted absorption. Proc Natl Acad Sci U S A 2020; 117:22833-22840. [PMID: 32873643 DOI: 10.1073/pnas.2005981117] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Channelrhodopsins are light-gated ion channels widely used to control neuronal firing with light (optogenetics). We report two previously unknown families of anion channelrhodopsins (ACRs), one from the heterotrophic protists labyrinthulea and the other from haptophyte algae. Four closely related labyrinthulea ACRs, named RubyACRs here, exhibit a unique retinal-binding pocket that creates spectral sensitivities with maxima at 590 to 610 nm, the most red-shifted channelrhodopsins known, long-sought for optogenetics, and more broadly the most red-shifted microbial rhodopsins thus far reported. We identified three spectral tuning residues critical for the red-shifted absorption. Photocurrents recorded from the RubyACR from Aurantiochytrium limacinum (designated AlACR1) under single-turnover excitation exhibited biphasic decay, the rate of which was only weakly voltage dependent, in contrast to that in previously characterized cryptophyte ACRs, indicating differences in channel gating mechanisms between the two ACR families. Moreover, in A. limacinum we identified three ACRs with absorption maxima at 485, 545, and 590 nm, indicating color-sensitive photosensing with blue, green, and red spectral variation of ACRs within individual species of the labyrinthulea family. We also report functional energy transfer from a cytoplasmic fluorescent protein domain to the retinal chromophore bound within RubyACRs.
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26
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Harris A, Lazaratos M, Siemers M, Watt E, Hoang A, Tomida S, Schubert L, Saita M, Heberle J, Furutani Y, Kandori H, Bondar AN, Brown LS. Mechanism of Inward Proton Transport in an Antarctic Microbial Rhodopsin. J Phys Chem B 2020; 124:4851-4872. [DOI: 10.1021/acs.jpcb.0c02767] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Andrew Harris
- Department of Physics, University of Guelph, 50 Stone Rd. E., Guelph, Ontario N1G 2W1, Canada
| | - Michalis Lazaratos
- Theoretical Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Malte Siemers
- Theoretical Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Ethan Watt
- Department of Physics, University of Guelph, 50 Stone Rd. E., Guelph, Ontario N1G 2W1, Canada
| | - Anh Hoang
- Department of Physics, University of Guelph, 50 Stone Rd. E., Guelph, Ontario N1G 2W1, Canada
| | - Sahoko Tomida
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Luiz Schubert
- Experimental Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Mattia Saita
- Experimental Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Yuji Furutani
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Ana-Nicoleta Bondar
- Theoretical Molecular Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Leonid S. Brown
- Department of Physics, University of Guelph, 50 Stone Rd. E., Guelph, Ontario N1G 2W1, Canada
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27
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Sineshchekov OA, Govorunova EG, Li H, Wang Y, Melkonian M, Wong GKS, Brown LS, Spudich JL. Conductance Mechanisms of Rapidly Desensitizing Cation Channelrhodopsins from Cryptophyte Algae. mBio 2020; 11:e00657-20. [PMID: 32317325 PMCID: PMC7175095 DOI: 10.1128/mbio.00657-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 03/26/2020] [Indexed: 01/14/2023] Open
Abstract
Channelrhodopsins guide algal phototaxis and are widely used as optogenetic probes for control of membrane potential with light. "Bacteriorhodopsin-like" cation channelrhodopsins (BCCRs) from cryptophytes differ in primary structure from other CCRs, lacking usual residues important for their cation conductance. Instead, the sequences of BCCR match more closely those of rhodopsin proton pumps, containing residues responsible for critical proton transfer reactions. We report 19 new BCCRs which, together with the earlier 6 known members of this family, form three branches (subfamilies) of a phylogenetic tree. Here, we show that the conductance mechanisms in two subfamilies differ with respect to involvement of the homolog of the proton donor in rhodopsin pumps. Two BCCRs from the genus Rhodomonas generate photocurrents that rapidly desensitize under continuous illumination. Using a combination of patch clamp electrophysiology, absorption, Raman spectroscopy, and flash photolysis, we found that the desensitization is due to rapid accumulation of a long-lived nonconducting intermediate of the photocycle with unusually blue-shifted absorption with a maximum at 330 nm. These observations reveal diversity within the BCCR family and contribute to deeper understanding of their independently evolved cation channel function.IMPORTANCE Cation channelrhodopsins, light-gated channels from flagellate green algae, are extensively used as optogenetic photoactivators of neurons in research and recently have progressed to clinical trials for vision restoration. However, the molecular mechanisms of their photoactivation remain poorly understood. We recently identified cryptophyte cation channelrhodopsins, structurally different from those of green algae, which have separately evolved to converge on light-gated cation conductance. This study reveals diversity within this new protein family and describes a subclade with unusually rapid desensitization that results in short transient photocurrents in continuous light. Such transient currents have not been observed in the green algae channelrhodopsins and are potentially useful in optogenetic protocols. Kinetic UV-visible (UV-vis) spectroscopy and photoelectrophysiology reveal that the desensitization is caused by rapid accumulation of a nonconductive photointermediate in the photochemical reaction cycle. The absorption maximum of the intermediate is 330 nm, the shortest wavelength reported in any rhodopsin, indicating a novel chromophore structure.
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Affiliation(s)
- Oleg A Sineshchekov
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Elena G Govorunova
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Hai Li
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Yumei Wang
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
| | - Michael Melkonian
- Institute for Plant Sciences, Department of Biology, University of Cologne, Cologne, Germany
- Central Collection of Algal Cultures, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Gane K-S Wong
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
- Beijing Genomics Institute-Shenzhen, Shenzhen, China
| | - Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada
| | - John L Spudich
- Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, Texas, USA
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28
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Hososhima S, Shigemura S, Kandori H, Tsunoda SP. Novel optogenetics tool: Gt_CCR4, a light-gated cation channel with high reactivity to weak light. Biophys Rev 2020; 12:453-459. [PMID: 32166612 DOI: 10.1007/s12551-020-00676-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022] Open
Abstract
Optogenetics is a growing technique which allows manipulation of biological events simply by illumination. The technique is appreciated especially in the neuroscience field because of its availability in controlling neuronal functions. A light-gated cation channel, Cr_ChR2 from Chlamydomonas reinhardtii, is the first and mostly applied to optogenetics for activating neuronal excitability. In addition, the molecular mechanism of Cr_ChR2 has been intensively studied by electrophysiology, spectroscopy, X-ray structural studies, etc. Novel cation channelrhodopsins from Guillardia theta, namely, Gt_CCR1-4, were discovered in 2016 and 2017. These channelrhodopsins are more homologous to haloarchaeal rhodopsins, particularly the proton pumps. Thus these cryptophyte-type light-gated cation channels are structurally and mechanistically distinct from chlorophyte channelrhodopsin such as Cr_ChR2. We here compared the photocurrent properties, cation selectivity, and kinetics between well-known Cr_ChR2 and Gt_CCR4. The light sensitivity of Gt_CCR4 is significantly higher than that of Cr_ChR2, while the channel open lifetime is in the same range as that of Cr_ChR2. Gt_CCR4 shows high Na+ selectivity in which the selectivity ratio for Na+ was 37-fold larger than that for Cr_ChR2, which primarily conducts H+. On the other hand, Gt_CCR4 conducted almost no H+ and no Ca2+ under physiological conditions. Other unique features and the applicability of Gt_CCR4 for optogenetics were discussed.
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Affiliation(s)
- Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Shunta Shigemura
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan.,OptoBio Technology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
| | - Satoshi P Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan. .,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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29
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Abstract
We previously reported a cation channelrhodopsin, Gt_CCR4, which is one of the 44 types of microbial rhodopsins from a cryptophyte flagellate, Guillardia theta. Due to the modest homology of amino acid sequences with a chlorophyte channelrhodopsin such as Cr_ChR2 from Chlamydomonas reinhardtii, it has been proposed that a family of cryptophyte channelrhodopsin, including Gt_CCR4, has a distinct molecular mechanism for channel gating and ion permeation. In this study, we compared the photocurrent properties, cation selectivity and kinetics between well-known Cr_ChR2 and Gt_CCR4 by a conventional path clamp method. Large and stable light-induced cation conduction by Gt_CCR4 at the maximum absorbing wavelength (530 nm) was observed with only small inactivation (15%), whereas the photocurrent of Cr_ChR2 exhibited significant inactivation (50%) and desensitization. The light sensitivity of Gt_CCR4 was higher (EC50 = 0.13 mW/mm2) than that of Cr_ChR2 (EC50 = 0.80 mW/mm2) while the channel open life time (photocycle speed) was in the same range as that of Cr_ChR2 (25~30 ms for Gt_CCR4 and 10~15 ms for Cr_ChR2). This observation implies that Gt_CCR4 enables optical neuronal spiking with weak light in high temporal resolution when applied in neuroscience. Furthermore, we demonstrated high Na+ selectivity of Gt_CCR4 in which the selectivity ratio for Na+ was 37-fold larger than that for Cr_ChR2, which primarily conducts H+. On the other hand, Gt_CCR4 conducted almost no H+ and no Ca2+ under physiological conditions. These results suggest that ion selectivity in Gt_CCR4 is distinct from that in Cr_ChR2. In addition, a unique red-absorbing and stable intermediate in the photocycle was observed, indicating a photochromic property of Gt_CCR4.
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30
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Oppermann J, Fischer P, Silapetere A, Liepe B, Rodriguez-Rozada S, Flores-Uribe J, Peter E, Keidel A, Vierock J, Kaufmann J, Broser M, Luck M, Bartl F, Hildebrandt P, Wiegert JS, Béjà O, Hegemann P, Wietek J. MerMAIDs: a family of metagenomically discovered marine anion-conducting and intensely desensitizing channelrhodopsins. Nat Commun 2019; 10:3315. [PMID: 31346176 PMCID: PMC6658528 DOI: 10.1038/s41467-019-11322-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/24/2019] [Indexed: 01/07/2023] Open
Abstract
Channelrhodopsins (ChRs) are algal light-gated ion channels widely used as optogenetic tools for manipulating neuronal activity. ChRs desensitize under continuous bright-light illumination, resulting in a significant decline of photocurrents. Here we describe a metagenomically identified family of phylogenetically distinct anion-conducting ChRs (designated MerMAIDs). MerMAIDs almost completely desensitize during continuous illumination due to accumulation of a late non-conducting photointermediate that disrupts the ion permeation pathway. MerMAID desensitization can be fully explained by a single photocycle in which a long-lived desensitized state follows the short-lived conducting state. A conserved cysteine is the critical factor in desensitization, as its mutation results in recovery of large stationary photocurrents. The rapid desensitization of MerMAIDs enables their use as optogenetic silencers for transient suppression of individual action potentials without affecting subsequent spiking during continuous illumination. Our results could facilitate the development of optogenetic tools from metagenomic databases and enhance general understanding of ChR function.
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Affiliation(s)
- Johannes Oppermann
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Paul Fischer
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Arita Silapetere
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Bernhard Liepe
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Silvia Rodriguez-Rozada
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, Falkenried 94, 20251, Hamburg, Germany
| | - José Flores-Uribe
- Technion-Israel Institute of Technology, 32000, Haifa, Israel
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
| | - Enrico Peter
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Anke Keidel
- Institute for Chemistry, Physical Chemistry/Biophysical Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Johannes Vierock
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Joel Kaufmann
- Institute for Biology, Biophysical Chemistry, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Matthias Broser
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Meike Luck
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Franz Bartl
- Institute for Biology, Biophysical Chemistry, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
| | - Peter Hildebrandt
- Institute for Chemistry, Physical Chemistry/Biophysical Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - J Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, Falkenried 94, 20251, Hamburg, Germany
| | - Oded Béjà
- Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany.
| | - Jonas Wietek
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany.
- Department of Neurobiology, Weizmann Institute of Science, 7610001, Rehovot, Israel.
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31
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Maróti P. Chemical rescue of H + delivery in proton transfer mutants of reaction center of photosynthetic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:317-324. [PMID: 30707884 DOI: 10.1016/j.bbabio.2019.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 12/05/2018] [Accepted: 01/25/2019] [Indexed: 11/27/2022]
Abstract
In the native and most mutant reaction centers of bacterial photosynthesis, the electron transfer is coupled to proton transfer and is rate limiting for the second reduction of QB- → QBH2. In the presence of divalent metal ions (e.g. Cd2+) or in some ("proton transfer") mutants (L210DN/M17DN or L213DN), the proton delivery to QB- is made rate limiting and the properties of the proton pathway can be directly examined. We found that small weak acids and buffers in large concentrations (up to 1 M) were able to rescue the severely impaired proton transfer capability differently depending on the location of the defects: lesions at the protein surface (proton gate H126H/H128H + Cd2+), beneath the surface (M17DN + Cd2+, L210DN/M17DN) or deep inside the protein (L213DN) could be completely, partially or to very small extent recovered, respectively. Small zwitterionic acids (azide/hydrazoic acid) and buffers (tricine) proved to be highly effective rescuers consistent with their enhanced binding affinity and access to any of the proton acceptors (including QB- itself) in the pathway. As a consequence, back titration of the protons at L212Glu could be observed as a pH-dependence of the rate constant of the charge recombination in the presence of azide or formate. Model calculations support the collective influence of the acid cluster on the change of the protonation states upon extension of the cluster with the bound small acid. In proton transfer mutants, the rescuing agents decreased the free energy of activation together with their enthalpic and entropic components. This is in agreement with the hypothesis that they function as protein-penetrating protonophores delivering protons into the chain and select dominating paths out of many alternate routes. We estimate that the proton delivery will be accelerated in one pathway out of 100-200 alternate pathways. The implications for design of the chemical recovery of impaired intra-protein proton transfer pathways in proton transfer mutants are discussed.
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Affiliation(s)
- Péter Maróti
- Institute of Medical Physics, University of Szeged, Hungary.
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32
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Fudim R, Szczepek M, Vierock J, Vogt A, Schmidt A, Kleinau G, Fischer P, Bartl F, Scheerer P, Hegemann P. Design of a light-gated proton channel based on the crystal structure of Coccomyxa rhodopsin. Sci Signal 2019; 12:12/573/eaav4203. [PMID: 30890657 DOI: 10.1126/scisignal.aav4203] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The light-driven proton pump Coccomyxa subellipsoidea rhodopsin (CsR) provides-because of its high expression in heterologous host cells-an opportunity to study active proton transport under controlled electrochemical conditions. In this study, solving crystal structure of CsR at 2.0-Å resolution enabled us to identify distinct features of the membrane protein that determine ion transport directivity and voltage sensitivity. A specific hydrogen bond between the highly conserved Arg83 and the nearby nonconserved tyrosine (Tyr14) guided our structure-based transformation of CsR into an operational light-gated proton channel (CySeR) that could potentially be used in optogenetic assays. Time-resolved electrophysiological and spectroscopic measurements distinguished pump currents from channel currents in a single protein and emphasized the necessity of Arg83 mobility in CsR as a dynamic extracellular barrier to prevent passive conductance. Our findings reveal that molecular constraints that distinguish pump from channel currents are structurally more confined than was generally expected. This knowledge might enable the structure-based design of novel optogenetic tools, which derive from microbial pumps and are therefore ion specific.
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Affiliation(s)
- Roman Fudim
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Michal Szczepek
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Johannes Vierock
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Arend Vogt
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Andrea Schmidt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Gunnar Kleinau
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Paul Fischer
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Franz Bartl
- Biophysical Chemistry, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute for Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany.
| | - Peter Hegemann
- Experimental Biophysics, Institute for Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany.
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