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Tanaka T, Hososhima S, Yamashita Y, Sugimoto T, Nakamura T, Shigemura S, Iida W, Sano FK, Oda K, Uchihashi T, Katayama K, Furutani Y, Tsunoda SP, Shihoya W, Kandori H, Nureki O. The high-light-sensitivity mechanism and optogenetic properties of the bacteriorhodopsin-like channelrhodopsin GtCCR4. Mol Cell 2024:S1097-2765(24)00670-1. [PMID: 39232582 DOI: 10.1016/j.molcel.2024.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 07/12/2024] [Accepted: 08/09/2024] [Indexed: 09/06/2024]
Abstract
Channelrhodopsins are microbial light-gated ion channels that can control the firing of neurons in response to light. Among several cation channelrhodopsins identified in Guillardia theta (GtCCRs), GtCCR4 has higher light sensitivity than typical channelrhodopsins. Furthermore, GtCCR4 shows superior properties as an optogenetic tool, such as minimal desensitization. Our structural analyses of GtCCR2 and GtCCR4 revealed that GtCCR4 has an outwardly bent transmembrane helix, resembling the conformation of activated G-protein-coupled receptors. Spectroscopic and electrophysiological comparisons suggested that this helix bend in GtCCR4 omits channel recovery time and contributes to high light sensitivity. An electrophysiological comparison of GtCCR4 and the well-characterized optogenetic tool ChRmine demonstrated that GtCCR4 has superior current continuity and action-potential spike generation with less invasiveness in neurons. We also identified highly active mutants of GtCCR4. These results shed light on the diverse structures and dynamics of microbial rhodopsins and demonstrate the strong optogenetic potential of GtCCR4.
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Affiliation(s)
- Tatsuki Tanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Shoko Hososhima
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Yo Yamashita
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Teppei Sugimoto
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Toshiki Nakamura
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Shunta Shigemura
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Wataru Iida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Fumiya K Sano
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Kazumasa Oda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Takayuki Uchihashi
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan; Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan; Institute for Glyco-core Research, Nagoya University, Nagoya, Aichi 464-0814, Japan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Yuji Furutani
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Satoshi P Tsunoda
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Wataru Shihoya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan.
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan.
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2
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Ohki Y, Shinone T, Inoko S, Sudo M, Demura M, Kikukawa T, Tsukamoto T. The preferential transport of NO 3- by full-length Guillardia theta anion channelrhodopsin 1 is enhanced by its extended cytoplasmic domain. J Biol Chem 2023; 299:105305. [PMID: 37778732 PMCID: PMC10637977 DOI: 10.1016/j.jbc.2023.105305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 09/21/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023] Open
Abstract
Previous research of anion channelrhodopsins (ACRs) has been performed using cytoplasmic domain (CPD)-deleted constructs and therefore have overlooked the native functions of full-length ACRs and the potential functional role(s) of the CPD. In this study, we used the recombinant expression of full-length Guillardia theta ACR1 (GtACR1_full) for pH measurements in Pichia pastoris cell suspensions as an indirect method to assess its anion transport activity and for absorption spectroscopy and flash photolysis characterization of the purified protein. The results show that the CPD, which was predicted to be intrinsically disordered and possibly phosphorylated, enhanced NO3- transport compared to Cl- transport, which resulted in the preferential transport of NO3-. This correlated with the extended lifetime and large accumulation of the photocycle intermediate that is involved in the gate-open state. Considering that the depletion of a nitrogen source enhances the expression of GtACR1 in native algal cells, we suggest that NO3- transport could be the natural function of GtACR1_full in algal cells.
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Affiliation(s)
- Yuya Ohki
- Division of Soft Matter, Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Tsukasa Shinone
- Division of Soft Matter, Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Sayo Inoko
- Division of Macromolecular Functions, Department of Biological Science, School of Science, Hokkaido University, Sapporo, Japan
| | - Miu Sudo
- Division of Macromolecular Functions, Department of Biological Science, School of Science, Hokkaido University, Sapporo, Japan
| | - Makoto Demura
- Division of Soft Matter, Graduate School of Life Science, Hokkaido University, Sapporo, Japan; Division of Macromolecular Functions, Department of Biological Science, School of Science, Hokkaido University, Sapporo, Japan; Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Takashi Kikukawa
- Division of Soft Matter, Graduate School of Life Science, Hokkaido University, Sapporo, Japan; Division of Macromolecular Functions, Department of Biological Science, School of Science, Hokkaido University, Sapporo, Japan; Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Takashi Tsukamoto
- Division of Soft Matter, Graduate School of Life Science, Hokkaido University, Sapporo, Japan; Division of Macromolecular Functions, Department of Biological Science, School of Science, Hokkaido University, Sapporo, Japan; Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan.
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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: 7] [Impact Index Per Article: 7.0] [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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Hagio H, Koyama W, Hosaka S, Song AD, Narantsatsral J, Matsuda K, Shimizu T, Hososhima S, Tsunoda SP, Kandori H, Hibi M. Optogenetic manipulation of neuronal and cardiomyocyte functions in zebrafish using microbial rhodopsins and adenylyl cyclases. eLife 2023; 12:e83975. [PMID: 37589546 PMCID: PMC10435232 DOI: 10.7554/elife.83975] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 07/25/2023] [Indexed: 08/18/2023] Open
Abstract
Even though microbial photosensitive proteins have been used for optogenetics, their use should be optimized to precisely control cell and tissue functions in vivo. We exploited GtCCR4 and KnChR, cation channelrhodopsins from algae, BeGC1, a guanylyl cyclase rhodopsin from a fungus, and photoactivated adenylyl cyclases (PACs) from cyanobacteria (OaPAC) or bacteria (bPAC), to control cell functions in zebrafish. Optical activation of GtCCR4 and KnChR in the hindbrain reticulospinal V2a neurons, which are involved in locomotion, induced swimming behavior at relatively short latencies, whereas activation of BeGC1 or PACs achieved it at long latencies. Activation of GtCCR4 and KnChR in cardiomyocytes induced cardiac arrest, whereas activation of bPAC gradually induced bradycardia. KnChR activation led to an increase in intracellular Ca2+ in the heart, suggesting that depolarization caused cardiac arrest. These data suggest that these optogenetic tools can be used to reveal the function and regulation of zebrafish neurons and cardiomyocytes.
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Affiliation(s)
- Hanako Hagio
- Graduate School of Science, Nagoya University, JapanNagoyaJapan
- Graduate School of Bioagricultural Sciences, Nagoya UniversityNagoyaJapan
- Institute for Advanced Research, Nagoya UniversityNagoyaJapan
| | - Wataru Koyama
- Graduate School of Science, Nagoya University, JapanNagoyaJapan
| | - Shiori Hosaka
- Graduate School of Science, Nagoya University, JapanNagoyaJapan
| | | | | | - Koji Matsuda
- Graduate School of Science, Nagoya University, JapanNagoyaJapan
| | - Takashi Shimizu
- Graduate School of Science, Nagoya University, JapanNagoyaJapan
| | - Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyNagoyaJapan
| | - Satoshi P Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyNagoyaJapan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of TechnologyNagoyaJapan
| | - Masahiko Hibi
- Graduate School of Science, Nagoya University, JapanNagoyaJapan
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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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Sanyal SK, Sharma K, Bisht D, Sharma S, Kateriya S, Pandey GK. Role of calcium sensor protein module CBL-CIPK in abiotic stress and light signaling responses in green algae. Int J Biol Macromol 2023; 237:124163. [PMID: 36965564 DOI: 10.1016/j.ijbiomac.2023.124163] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/14/2023] [Accepted: 03/20/2023] [Indexed: 03/27/2023]
Abstract
Ca2+ signaling is an important biological process that enable to perceive and communicate information in the cell. Our current understanding of the signaling system suggests that plants and animals have certain differences in signal-sensing mechanisms. The Ca2+-mediated CBL-CIPK module has emerged as a major sensor responder network for Ca2+ signaling and has been speculated to be involved in plant terrestrial life adaptation. This module has previously been reported in Archaeplastids, Chromalveolates, and Excavates. In our experimental analysis of Chlamydomonas reinhardtii CBLs, we proved that the CrCBL1 protein interacts with Phototropin and Channelrhodopsin, and the expression of CrCBLs is modulated by light. Further analysis using chlorophyte and streptophyte algal sequences allowed us to identify the differences that have evolved in CBL and CIPK proteins since plants have progressed from aquatic to terrestrial habitats. Moreover, an investigation of Klebsormidium CBL and CIPK genes led us to know that they are abiotic stress stimuli-responsive, indicating that their role was defined very early during terrestrial adaptations. Structure-based prediction and Ca2+-binding assays indicated that the KnCBL1 protein in Klebsormidium showed a typical Ca2+-binding pocket. In summary, the results of this study suggest that these stress-responsive proteins enable crosstalk between Ca2+ and light signaling pathways very early during plant adaptation from aquatic to terrestrial habitats.
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Affiliation(s)
- Sibaji K Sanyal
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India; Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Komal Sharma
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India; Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Diksha Bisht
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India
| | - Sunita Sharma
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Suneel Kateriya
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India.
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8
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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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9
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Shimono K, Dencher NA. Recent advances in signaling and activation mechanism in microbial rhodopsins: Report for the session 6 at the 19 th International Conference on Retinal Proteins. Biophys Physicobiol 2023; 20:e201009. [PMID: 38362314 PMCID: PMC10865883 DOI: 10.2142/biophysico.bppb-v20.s009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 01/23/2023] [Indexed: 01/25/2023] Open
Affiliation(s)
- Kazumi Shimono
- Faculty of Pharmaceutical Sciences, Sojo Universtiy, Kumamoto 860-0082, Japan
| | - Norbert A. Dencher
- Department Chemistry, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
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10
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Bi X, Beck C, Gong Y. A kinetic-optimized CoChR variant with enhanced high-frequency spiking fidelity. Biophys J 2022; 121:4166-4178. [PMID: 36151721 PMCID: PMC9675021 DOI: 10.1016/j.bpj.2022.09.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/09/2022] [Accepted: 09/21/2022] [Indexed: 11/22/2022] Open
Abstract
Channelrhodopsins are a promising toolset for noninvasive optical manipulation of genetically identifiable neuron populations. Existing channelrhodopsins have generally suffered from a trade-off between two desired properties: fast channel kinetics and large photocurrent. Such a trade-off hinders spatiotemporally precise optogenetic activation during both one-photon and two-photon photostimulation. Furthermore, the simultaneous use of spectrally separated genetically encoded indicators and channelrhodopsins has generally suffered from non-negligible crosstalk in photocurrent or fluorescence. These limitations have hindered crosstalk-free dual-channel experiments needed to establish relationships between multiple neural populations. Recent large-scale transcriptome sequencing revealed one potent optogenetic actuator, the channelrhodopsin from species Chloromonas oogama (CoChR), which possessed high cyan light-driven photocurrent but slow channel kinetics. We rationally designed and engineered a kinetic-optimized CoChR variant that was faster than native CoChR while maintaining large photocurrent amplitude. When expressed in cultured hippocampal pyramidal neurons, our CoChR variant improved high-frequency spiking fidelity under one-photon illumination. Our CoChR variant's blue-shifted excitation spectrum enabled simultaneous cyan photostimulation and red calcium imaging with negligible photocurrent crosstalk.
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Affiliation(s)
- Xiaoke Bi
- Department of Biomedical Engineering, Duke University, Durham, North Carolina.
| | - Connor Beck
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University, Durham, North Carolina.
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Hososhima S, Abe-Yoshizumi R, Kandori H. Functional assay of light-induced ion-transport by rhodopsins. Methods Enzymol 2022; 679:331-342. [PMID: 36682869 DOI: 10.1016/bs.mie.2022.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Microbial rhodopsins are photoreceptive membrane proteins found from diverse microorganisms such as archaea, eubacteria, eukaryotes and viruses. Many microbial rhodopsins possess ion-transport activity by light, such as channels and pumps, and ion-transporting rhodopsins are important tools in optogenetics that control animal behavior by light. Historically, molecular mechanism of rhodopsins has been studied by spectroscopic methods for purified proteins. On the other hand, ion-transport function has to be studied by different methods. This chapter introduces two methods of functional assay of ion-transporting rhodopsins by light. One is a patch clamp method using mammalian cells, and another is an ion-transport assay using pH electrode and microbial cells. These functional assay provides fundamental data of ion-transporting rhodopsins, and thus contributes to evaluation for optogenetic tools.
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Affiliation(s)
- Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Rei Abe-Yoshizumi
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan; OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan.
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Beck C, Gong Y. Engineering rhodopsins' activation spectra using a FRET-based approach. Biophys J 2022; 121:1765-1776. [PMID: 35331688 PMCID: PMC9117881 DOI: 10.1016/j.bpj.2022.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/01/2021] [Accepted: 03/18/2022] [Indexed: 11/16/2022] Open
Abstract
In the past decade, optogenetics has become a nearly ubiquitous tool in neuroscience because it enables researchers to manipulate neural activity with high temporal resolution and genetic specificity. Rational engineering of optogenetic tools has produced channelrhodopsins with a wide range of kinetics and photocurrent magnitude. Genome mining for previously unidentified species of rhodopsin has uncovered optogenetic tools with diverse spectral sensitivities. However, rational engineering of a rhodopsin has thus far been unable to re-engineer spectral sensitivity while preserving full photocurrent. Here, we developed and characterized ChroME-mTFP, a rhodopsin-fluorescent protein fusion that drives photocurrent through Förster resonance energy transfer (FRET). This FRET-opsin mechanism artificially broadened the activation spectrum of the blue-green-light-activated rhodopsin ChroME by approximately 50 nm, driving higher photocurrent at blue-shifted excitation wavelengths without sacrificing kinetics. The excitation spectra's increase at short wavelengths enabled us to optogenetically excite neurons at lower excitation powers with shorter wavelengths of light. Increasing this rhodopsin's sensitivity to shorter, bluer wavelengths pushes it toward dual-channel, crosstalk-free optogenetic stimulation and imaging with green-light-activated sensors. However, this iteration of FRET-opsin suffers from some imaging-light-induced photocurrent crosstalk from green or yellow light due to maintained, low-efficiency excitation at longer wavelengths.
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Affiliation(s)
- Connor Beck
- Department of Biomedical Engineering, Duke University, Durham, North Carolina.
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University, Durham, North Carolina.
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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: 19] [Impact Index Per Article: 9.5] [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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Abstract
Rhodopsins are photoreceptive membrane proteins consisting of a common heptahelical transmembrane architecture that contains a retinal chromophore. Rhodopsin was first discovered in the animal retina in 1876, but a different type of rhodopsin, bacteriorhodopsin, was reported to be present in the cell membrane of an extreme halophilic archaeon, Halobacterium salinarum, 95 years later. Although these findings were made by physiological observation of pigmented tissue and cell bodies, recent progress in genomic and metagenomic analyses has revealed that there are more than 10,000 microbial rhodopsins and 9000 animal rhodopsins with large diversity and tremendous new functionality. In this Cell Science at a Glance article and accompanying poster, we provide an overview of the diversity of functions, structures, color discrimination mechanisms and optogenetic applications of these two rhodopsin families, and will also highlight the third distinctive rhodopsin family, heliorhodopsin.
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Affiliation(s)
- Takashi Nagata
- 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
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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