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Govorunova EG, Sineshchekov OA, Li H, Gou Y, Chen H, Yang S, Wang Y, Mitchell S, Palmateer A, Brown LS, St-Pierre F, Xue M, Spudich JL. Blue-shifted ancyromonad channelrhodopsins for multiplex optogenetics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.02.24.639930. [PMID: 40060592 PMCID: PMC11888301 DOI: 10.1101/2025.02.24.639930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/20/2025]
Abstract
Light-gated ion channels from protists (channelrhodopsins or ChRs) are optogenetic tools widely used for controlling neurons and cardiomyocytes. Multiplex optogenetic applications require spectrally separated molecules that must be found in nature, as they are difficult to engineer without disrupting channel function. Scanning numerous sequence databases, we identified three robust naturally blue-shifted ChRs from ancyromonads. They form a separate branch on the phylogenetic tree and contain residue motifs characteristic of anion ChRs (ACRs). However, only two conduct chloride, whereas the close Nutomonas longa homolog (peak absorption at ~440 nm) generates inward cation currents in mammalian cells under physiological conditions, significantly exceeding those by previously known tools. Measurements of transient absorption changes and pH titration of purified Ancyromonas sigmoides ACR (AnsACR) combined with mutant analysis revealed the roles of the residues in the photoactive site. Both ancyromonad ACRs allowed optogenetic silencing of mouse cortical neurons in brain slices. AnsACR expression in the cholinergic neurons enabled photoinhibition of pharyngeal muscle contraction in live worms. AnsACR could be activated by near-infrared two-photon illumination, which is required to control specific neurons in thick tissue. Our results improved the mechanistic understanding of light-gated channel function and expanded the optogenetic toolkit. Impact statement Ancyromonad channelrhodopsins advance our understanding of ionic selectivity and wavelength regulation in light-gated ion channels and also expand the toolkit for all-optical electrophysiology.
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Affiliation(s)
- 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
| | - 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
| | - 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
| | - Yueyang Gou
- Department of Neuroscience, Baylor College of Medicine; Houston, TX 77030, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston, TX 77030, USA
| | - Hongmei Chen
- Department of Neuroscience, Baylor College of Medicine; Houston, TX 77030, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston, TX 77030, USA
| | - Shuyuan Yang
- Department of Neuroscience, Baylor College of Medicine; 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
| | - Stephen Mitchell
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph; Guelph, Ontario N1G 2W1, Canada
| | - Alyssa Palmateer
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph; Guelph, Ontario N1G 2W1, Canada
| | - Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph; Guelph, Ontario N1G 2W1, Canada
| | - François St-Pierre
- Department of Neuroscience, Baylor College of Medicine; Houston, TX 77030, USA
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX 77005, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 7705, USA
| | - Mingshan Xue
- Department of Neuroscience, Baylor College of Medicine; Houston, TX 77030, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, 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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Oppermann J, Rozenberg A, Fabrin T, González-Cabrera C, Parker R, Béjà O, Prigge M, Hegemann P. Robust optogenetic inhibition with red-light-sensitive anion-conducting channelrhodopsins. eLife 2024; 12:RP90100. [PMID: 39401075 PMCID: PMC11473104 DOI: 10.7554/elife.90100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2024] Open
Abstract
Channelrhodopsins (ChRs) are light-gated ion channels widely used to optically activate or silence selected electrogenic cells, such as individual brain neurons. Here, we describe identifying and characterizing a set of anion-conducting ChRs (ACRs) from diverse taxa and representing various branches of the ChR phylogenetic tree. The Mantoniella squamata ACR (MsACR1) showed high sensitivity to yellow-green light (λmax at 555 nm) and was further engineered for optogenetic applications. A single amino-acid substitution that mimicked red-light-sensitive rhodopsins like Chrimson shifted the photosensitivity 20 nm toward red light and accelerated photocurrent kinetics. Hence, it was named red and accelerated ACR, raACR. Both wild-type and mutant are capable optical silencers at low light intensities in mouse neurons in vitro and in vivo, while raACR offers a higher temporal resolution.
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Affiliation(s)
- Johannes Oppermann
- Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu BerlinBerlinGermany
| | - Andrey Rozenberg
- Faculty of Biology, Technion – Israel Institute of TechnologyHaifaIsrael
| | - Thomaz Fabrin
- Research Group Neuromodulatory Networks, Leibniz Institute for NeurobiologyMagdeburgGermany
| | - Cristian González-Cabrera
- Research Group Neuromodulatory Networks, Leibniz Institute for NeurobiologyMagdeburgGermany
- Aligning Science Across Parkinson's (ASAP) Collaborative Research NetworkChevy ChaseUnited States
| | - Rafael Parker
- Research Group Neuromodulatory Networks, Leibniz Institute for NeurobiologyMagdeburgGermany
- Aligning Science Across Parkinson's (ASAP) Collaborative Research NetworkChevy ChaseUnited States
| | - Oded Béjà
- Faculty of Biology, Technion – Israel Institute of TechnologyHaifaIsrael
| | - Matthias Prigge
- Research Group Neuromodulatory Networks, Leibniz Institute for NeurobiologyMagdeburgGermany
- Aligning Science Across Parkinson's (ASAP) Collaborative Research NetworkChevy ChaseUnited States
- Center for Behavioral Brain Sciences, CBBSMagdeburgGermany
| | - Peter Hegemann
- Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu BerlinBerlinGermany
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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 PMCID: PMC10932829 DOI: 10.1016/j.jmb.2023.168298] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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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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: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [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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