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Barykina NV, Carey EM, Oliinyk OS, Nimmerjahn A, Verkhusha VV. Destabilized near-infrared fluorescent nanobodies enable background-free targeting of GFP-based biosensors for imaging and manipulation. Nat Commun 2024; 15:7788. [PMID: 39242569 PMCID: PMC11379940 DOI: 10.1038/s41467-024-51857-x] [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: 12/19/2023] [Accepted: 08/19/2024] [Indexed: 09/09/2024] Open
Abstract
Near-infrared (NIR) probes are highly sought after as fluorescent tags for multicolor cellular and in vivo imaging. Here we develop small NIR fluorescent nanobodies, termed NIR-FbLAG16 and NIR-FbLAG30, enabling background-free visualization of various GFP-derived probes and biosensors. We also design a red-shifted variant, NIR-Fb(718), to simultaneously target several antigens within the NIR spectral range. Leveraging the antigen-stabilizing property of the developed NIR-Fbs, we then create two modular systems for precise control of gene expression in GFP-labeled cells. Applying the NIR-Fbs in vivo, we target cells expressing GFP and the calcium biosensor GCaMP6 in the somatosensory cortex of transgenic mice. Simultaneously tracking calcium activity and the reference signal from NIR-FbLAGs bound to GCaMP6 enables ratiometric deep-brain in vivo imaging. Altogether, NIR-FbLAGs present a promising approach for imaging and manipulating various processes in live cells and behaving animals expressing GFP-based probes.
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Affiliation(s)
- Natalia V Barykina
- Department of Genetics, and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, NY, 10461, USA
| | - Erin M Carey
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Olena S Oliinyk
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Vladislav V Verkhusha
- Department of Genetics, and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, NY, 10461, USA.
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland.
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2
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Jensen GC, Janis MK, Nguyen HN, David OW, Zastrow ML. Fluorescent Protein-Based Sensors for Detecting Essential Metal Ions across the Tree of Life. ACS Sens 2024; 9:1622-1643. [PMID: 38587931 PMCID: PMC11073808 DOI: 10.1021/acssensors.3c02695] [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: 04/10/2024]
Abstract
Genetically encoded fluorescent metal ion sensors are powerful tools for elucidating metal dynamics in living systems. Over the last 25 years since the first examples of genetically encoded fluorescent protein-based calcium indicators, this toolbox of probes has expanded to include other essential and non-essential metal ions. Collectively, these tools have illuminated fundamental aspects of metal homeostasis and trafficking that are crucial to fields ranging from neurobiology to human nutrition. Despite these advances, much of the application of metal ion sensors remains limited to mammalian cells and tissues and a limited number of essential metals. Applications beyond mammalian systems and in vivo applications in living organisms have primarily used genetically encoded calcium ion sensors. The aim of this Perspective is to provide, with the support of historical and recent literature, an updated and critical view of the design and use of fluorescent protein-based sensors for detecting essential metal ions in various organisms. We highlight the historical progress and achievements with calcium sensors and discuss more recent advances and opportunities for the detection of other essential metal ions. We also discuss outstanding challenges in the field and directions for future studies, including detecting a wider variety of metal ions, developing and implementing a broader spectral range of sensors for multiplexing experiments, and applying sensors to a wider range of single- and multi-species biological systems.
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Affiliation(s)
- Gary C Jensen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Makena K Janis
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Hazel N Nguyen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Ogonna W David
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Melissa L Zastrow
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
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3
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Subach OM, Vlaskina AV, Agapova YK, Nikolaeva AY, Varizhuk AM, Podgorny OV, Piatkevich KD, Patrushev MV, Boyko KM, Subach FV. YTnC2, an improved genetically encoded green calcium indicator based on toadfish troponin C. FEBS Open Bio 2023; 13:2047-2060. [PMID: 37650870 PMCID: PMC10626279 DOI: 10.1002/2211-5463.13702] [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: 06/01/2023] [Revised: 08/03/2023] [Accepted: 08/30/2023] [Indexed: 09/01/2023] Open
Abstract
Genetically encoded calcium indicators based on truncated troponin C are attractive probes for calcium imaging due to their relatively small molecular size and twofold reduced calcium ion buffering. However, the best-suited members of this family, YTnC and cNTnC, suffer from low molecular brightness, limited dynamic range, and/or poor sensitivity to calcium transients in neurons. To overcome these limitations, we developed an enhanced version of YTnC, named YTnC2. Compared with YTnC, YTnC2 had 5.7-fold higher molecular brightness and 6.4-fold increased dynamic range in vitro. YTnC2 was successfully used to reveal calcium transients in the cytosol and in the lumen of mitochondria of both mammalian cells and cultured neurons. Finally, we obtained and analyzed the crystal structure of the fluorescent domain of the YTnC2 mutant.
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Affiliation(s)
- Oksana M. Subach
- Complex of NBICS TechnologiesNational Research Center “Kurchatov Institute”MoscowRussia
| | - Anna V. Vlaskina
- Complex of NBICS TechnologiesNational Research Center “Kurchatov Institute”MoscowRussia
| | - Yulia K. Agapova
- Complex of NBICS TechnologiesNational Research Center “Kurchatov Institute”MoscowRussia
| | - Alena Y. Nikolaeva
- Complex of NBICS TechnologiesNational Research Center “Kurchatov Institute”MoscowRussia
- Bach Institute of BiochemistryResearch Centre of Biotechnology of the Russian Academy of SciencesMoscowRussia
| | - Anna M. Varizhuk
- Federal Research and Clinical Center of Physical‐Chemical Medicine of Federal Medical Biological AgencyMoscowRussia
- Moscow Institute of Physics and TechnologyDolgoprudnyRussia
| | - Oleg V. Podgorny
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic ChemistryRASMoscowRussia
- Center for Precision Genome Editing and Genetic Technologies for BiomedicinePirogov Russian National Research Medical UniversityMoscowRussia
- Federal Center of Brain Research and Neurotechnologies of Federal Medical Biological AgencyMoscowRussia
| | - Kiryl D. Piatkevich
- School of Life SciencesWestlake UniversityHangzhouChina
- Westlake Laboratory of Life Sciences and BiomedicineHangzhouChina
| | - Maxim V. Patrushev
- Complex of NBICS TechnologiesNational Research Center “Kurchatov Institute”MoscowRussia
| | - Konstantin M. Boyko
- Bach Institute of BiochemistryResearch Centre of Biotechnology of the Russian Academy of SciencesMoscowRussia
| | - Fedor V. Subach
- Complex of NBICS TechnologiesNational Research Center “Kurchatov Institute”MoscowRussia
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4
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Subach OM, Varfolomeeva L, Vlaskina AV, Agapova YK, Nikolaeva AY, Piatkevich KD, Patrushev MV, Boyko KM, Subach FV. FNCaMP, ratiometric green calcium indicator based on mNeonGreen protein. Biochem Biophys Res Commun 2023; 665:169-177. [PMID: 37163937 DOI: 10.1016/j.bbrc.2023.04.108] [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: 04/18/2023] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/12/2023]
Abstract
Neurobiologists widely use green genetically encoded calcium indicators (GECIs) for visualization of neuronal activity. Among them, ratiometric GECIs allow imaging of both active and non-active neuronal populations. However, they are not popular, since their properties are inferior to intensiometric GCaMP series of GECIs. The most characterized and developed ratiometric green GECI is FGCaMP7. However, the dynamic range and sensitivity of its large Stock's shift green (LSS-Green) form is significantly lower than its Green form and its molecular design is not optimal. To address these drawbacks, we engineered a ratiometric green calcium indicator, called FNCaMP, which is based on bright mNeonGreen protein and calmodulin from A. niger and has optimal NTnC-like design. We compared the properties of the FNCaMP and FGCaMP7 indicators in vitro, in mammalian cells, and in neuronal cultures. Finally, we obtained and analyzed X-ray structure of the FNCaMP indicator.
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Affiliation(s)
- Oksana M Subach
- Complex of NBICS Technologies, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
| | - Larisa Varfolomeeva
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia.
| | - Anna V Vlaskina
- Complex of NBICS Technologies, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
| | - Yulia K Agapova
- Complex of NBICS Technologies, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
| | - Alena Y Nikolaeva
- Complex of NBICS Technologies, National Research Center "Kurchatov Institute", Moscow, 123182, Russia; Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia.
| | - Kiryl D Piatkevich
- School of Life Sciences, Westlake University, Hangzhou, 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, 310024, China.
| | - Maxim V Patrushev
- Complex of NBICS Technologies, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
| | - Konstantin M Boyko
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia.
| | - Fedor V Subach
- Complex of NBICS Technologies, National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
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5
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Zhang Y, Rózsa M, Liang Y, Bushey D, Wei Z, Zheng J, Reep D, Broussard GJ, Tsang A, Tsegaye G, Narayan S, Obara CJ, Lim JX, Patel R, Zhang R, Ahrens MB, Turner GC, Wang SSH, Korff WL, Schreiter ER, Svoboda K, Hasseman JP, Kolb I, Looger LL. Fast and sensitive GCaMP calcium indicators for imaging neural populations. Nature 2023; 615:884-891. [PMID: 36922596 PMCID: PMC10060165 DOI: 10.1038/s41586-023-05828-9] [Citation(s) in RCA: 199] [Impact Index Per Article: 199.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/10/2023] [Indexed: 03/17/2023]
Abstract
Calcium imaging with protein-based indicators1,2 is widely used to follow neural activity in intact nervous systems, but current protein sensors report neural activity at timescales much slower than electrical signalling and are limited by trade-offs between sensitivity and kinetics. Here we used large-scale screening and structure-guided mutagenesis to develop and optimize several fast and sensitive GCaMP-type indicators3-8. The resulting 'jGCaMP8' sensors, based on the calcium-binding protein calmodulin and a fragment of endothelial nitric oxide synthase, have ultra-fast kinetics (half-rise times of 2 ms) and the highest sensitivity for neural activity reported for a protein-based calcium sensor. jGCaMP8 sensors will allow tracking of large populations of neurons on timescales relevant to neural computation.
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Affiliation(s)
- Yan Zhang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Márton Rózsa
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Allen Institute for Neural Dynamics, Seattle, WA, USA
| | - Yajie Liang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Daniel Bushey
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Ziqiang Wei
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Jihong Zheng
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Daniel Reep
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | | | - Arthur Tsang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Getahun Tsegaye
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Sujatha Narayan
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Allen Institute for Neural Dynamics, Seattle, WA, USA
| | | | - Jing-Xuan Lim
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Ronak Patel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Rongwei Zhang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Misha B Ahrens
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Glenn C Turner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
| | - Samuel S-H Wang
- Neuroscience Institute, Princeton University, Princeton, NJ, USA.
| | - Wyatt L Korff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Eric R Schreiter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Karel Svoboda
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
- Allen Institute for Neural Dynamics, Seattle, WA, USA.
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
| | - Jeremy P Hasseman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
| | - Ilya Kolb
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
- Genetically Encoded Neural Indicator and Effector (GENIE) Project, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA.
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6
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Krueger TD, Tang L, Fang C. Delineating Ultrafast Structural Dynamics of a Green-Red Fluorescent Protein for Calcium Sensing. BIOSENSORS 2023; 13:bios13020218. [PMID: 36831983 PMCID: PMC9954042 DOI: 10.3390/bios13020218] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 05/14/2023]
Abstract
Fluorescent proteins (FPs) are indispensable tools for noninvasive bioimaging and sensing. Measuring the free cellular calcium (Ca2+) concentrations in vivo with genetically encodable FPs can be a relatively direct measure of neuronal activity due to the complex signaling role of these ions. REX-GECO1 is a recently developed red-green emission and excitation ratiometric FP-based biosensor that achieves a high dynamic range due to differences in the chromophore response to light excitation with and without calcium ions. Using steady-state electronic measurements (UV/Visible absorption and emission), along with time-resolved spectroscopic techniques including femtosecond transient absorption (fs-TA) and femtosecond stimulated Raman spectroscopy (FSRS), the potential energy surfaces of these unique biosensors are unveiled with vivid details. The ground-state structural characterization of the Ca2+-free biosensor via FSRS reveals a more spacious protein pocket that allows the chromophore to efficiently twist and reach a dark state. In contrast, the more compressed cavity within the Ca2+-bound biosensor results in a more heterogeneous distribution of chromophore populations that results in multi-step excited state proton transfer (ESPT) pathways on the sub-140 fs, 600 fs, and 3 ps timescales. These results enable rational design strategies to enlarge the spectral separation between the protonated/deprotonated forms and the Stokes shift leading to a larger dynamic range and potentially higher fluorescence quantum yield, which should be broadly applicable to the calcium imaging and biosensor communities.
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7
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Sotskov VP, Pospelov NA, Plusnin VV, Anokhin KV. Calcium Imaging Reveals Fast Tuning Dynamics of Hippocampal Place Cells and CA1 Population Activity during Free Exploration Task in Mice. Int J Mol Sci 2022; 23:ijms23020638. [PMID: 35054826 PMCID: PMC8775446 DOI: 10.3390/ijms23020638] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 02/06/2023] Open
Abstract
Hippocampal place cells are a well-known object in neuroscience, but their place field formation in the first moments of navigating in a novel environment remains an ill-defined process. To address these dynamics, we performed in vivo imaging of neuronal activity in the CA1 field of the mouse hippocampus using genetically encoded green calcium indicators, including the novel NCaMP7 and FGCaMP7, designed specifically for in vivo calcium imaging. Mice were injected with a viral vector encoding calcium sensor, head-mounted with an NVista HD miniscope, and allowed to explore a completely novel environment (circular track surrounded by visual cues) without any reinforcement stimuli, in order to avoid potential interference from reward-related behavior. First, we calculated the average time required for each CA1 cell to acquire its place field. We found that 25% of CA1 place fields were formed at the first arrival in the corresponding place, while the average tuning latency for all place fields in a novel environment equaled 247 s. After 24 h, when the environment was familiar to the animals, place fields formed faster, independent of retention of cognitive maps during this session. No cumulation of selectivity score was observed between these two sessions. Using dimensionality reduction, we demonstrated that the population activity of rapidly tuned CA1 place cells allowed the reconstruction of the geometry of the navigated circular maze; the distribution of reconstruction error between the mice was consistent with the distribution of the average place field selectivity score in them. Our data thus show that neuronal activity recorded with genetically encoded calcium sensors revealed fast behavior-dependent plasticity in the mouse hippocampus, resulting in the rapid formation of place fields and population activity that allowed the reconstruction of the geometry of the navigated maze.
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Affiliation(s)
- Vladimir P. Sotskov
- Institute for Advanced Brain Studies, Lomonosov Moscow State University, 119991 Moscow, Russia;
- Correspondence: (V.P.S.); (K.V.A.)
| | - Nikita A. Pospelov
- Institute for Advanced Brain Studies, Lomonosov Moscow State University, 119991 Moscow, Russia;
| | - Viktor V. Plusnin
- National Research Center “Kurchatov Institute”, 123098 Moscow, Russia;
- Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Konstantin V. Anokhin
- Institute for Advanced Brain Studies, Lomonosov Moscow State University, 119991 Moscow, Russia;
- P.K. Anokhin Institute of Normal Physiology RAS, 125315 Moscow, Russia
- Correspondence: (V.P.S.); (K.V.A.)
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8
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Ratiometric two-photon fluorescence probes for sensing, imaging and biomedicine applications at living cell and small animal levels. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214114] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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9
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Lohr C, Beiersdorfer A, Fischer T, Hirnet D, Rotermund N, Sauer J, Schulz K, Gee CE. Using Genetically Encoded Calcium Indicators to Study Astrocyte Physiology: A Field Guide. Front Cell Neurosci 2021; 15:690147. [PMID: 34177468 PMCID: PMC8226001 DOI: 10.3389/fncel.2021.690147] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/06/2021] [Indexed: 01/14/2023] Open
Abstract
Ca2+ imaging is the most frequently used technique to study glial cell physiology. While chemical Ca2+ indicators served to visualize and measure changes in glial cell cytosolic Ca2+ concentration for several decades, genetically encoded Ca2+ indicators (GECIs) have become state of the art in recent years. Great improvements have been made since the development of the first GECI and a large number of GECIs with different physical properties exist, rendering it difficult to select the optimal Ca2+ indicator. This review discusses some of the most frequently used GECIs and their suitability for glial cell research.
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Affiliation(s)
- Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | | | - Timo Fischer
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Daniela Hirnet
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Natalie Rotermund
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Jessica Sauer
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Kristina Schulz
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Christine E Gee
- Institute of Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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10
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Baek K, Ji K, Peng W, Liyanaarachchi SM, Dodani SC. The design and evolution of fluorescent protein-based sensors for monoatomic ions in biology. Protein Eng Des Sel 2021; 34:gzab023. [PMID: 34581820 PMCID: PMC8477612 DOI: 10.1093/protein/gzab023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/18/2021] [Accepted: 08/18/2021] [Indexed: 12/15/2022] Open
Abstract
Living cells rely on a finely tuned symphony of inorganic ion gradients composed of both cations and anions. This delicate balance is maintained by biological receptors all acting in concert to selectively recognize and position ions for homeostasis. These dynamic processes can be intercepted and visualized with optical microscopy at the organismal, tissue, cellular and subcellular levels using fluorescent protein-based biosensors. Since the first report of such tool for calcium (Ca2+) in 1997, outstanding biological questions and innovations in protein engineering along with associated fields have driven the development of new biosensors for Ca2+ and beyond. In this Review, we summarize a workflow that can be used to generate fluorescent protein-based biosensors to study monoatomic ions in biology. To showcase the scope of this approach, we highlight recent advances reported for Ca2+ biosensors and in detail discuss representative case studies of biosensors reported in the last four years for potassium (K+), magnesium (Mg2+), copper (Cu2+/+), lanthanide (Ln3+) and chloride (Cl-) ions.
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Affiliation(s)
- Kiheon Baek
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, USA
| | - Ke Ji
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, USA
| | - Weicheng Peng
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, USA
| | - Sureshee M Liyanaarachchi
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, USA
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080, USA
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11
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Structure- and mechanism-guided design of single fluorescent protein-based biosensors. Nat Chem Biol 2021; 17:509-518. [PMID: 33558715 DOI: 10.1038/s41589-020-00718-x] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/02/2020] [Indexed: 12/22/2022]
Abstract
Intensiometric genetically encoded biosensors, based on allosteric modulation of the fluorescence of a single fluorescent protein, are powerful tools for enabling imaging of neural activities and other cellular biochemical events. The archetypical example of such biosensors is the GCaMP series of Ca2+ biosensors, which have been steadily improved over the past two decades and are now indispensable tools for neuroscience. However, no other biosensors have reached levels of performance, or had revolutionary impacts within specific disciplines, comparable to that of the Ca2+ biosensors. Of the many reasons why this has been the case, a critical one has been a general black-box view of biosensor structure and mechanism. With this Perspective, we aim to summarize what is known about biosensor structure and mechanisms and, based on this foundation, provide guidelines to accelerate the development of a broader range of biosensors with performance comparable to that of the GCaMP series.
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12
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Yudenko A, Smolentseva A, Maslov I, Semenov O, Goncharov IM, Nazarenko VV, Maliar NL, Borshchevskiy V, Gordeliy V, Remeeva A, Gushchin I. Rational Design of a Split Flavin-Based Fluorescent Reporter. ACS Synth Biol 2021; 10:72-83. [PMID: 33325704 DOI: 10.1021/acssynbio.0c00454] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein-fragment complementation assays are used ubiquitously for probing protein-protein interactions. Most commonly, the reporter protein is split in two parts, which are then fused to the proteins of interest and can reassemble and provide a readout if the proteins of interest interact with each other. The currently known split fluorescent proteins either can be used only in aerobic conditions and assemble irreversibly, or require addition of exogenous chromophores, which complicates the design of experiments. In recent years, light-oxygen-voltage (LOV) domains of several photoreceptor proteins have been developed into flavin-based fluorescent proteins (FbFPs) that, under some circumstances, can outperform commonly used fluorescent proteins such as GFP. Here, we show that CagFbFP, a small thermostable FbFP based on a LOV domain-containing protein from Chloroflexus aggregans, can serve as a split fluorescent reporter. We use the available genetic and structural information to identify three loops between the conserved secondary structure elements, Aβ-Bβ, Eα-Fα, and Hβ-Iβ, that tolerate insertion of flexible poly-Gly/Ser segments and eventually splitting. We demonstrate that the designed split pairs, when fused to interacting proteins, are fluorescent in vivo in E. coli and human cells and have low background fluorescence. Our results enable probing protein-protein interactions in anaerobic conditions without using exogenous fluorophores and provide a basis for further development of LOV and PAS (Per-Arnt-Sim) domain-based fluorescent reporters and optogenetic tools.
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Affiliation(s)
- Anna Yudenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Anastasia Smolentseva
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Ivan Maslov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Oleg Semenov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Ivan M. Goncharov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Vera V. Nazarenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Nina L. Maliar
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Valentin Borshchevskiy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Valentin Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
- Institut de Biologie Structurale J.-P. Ebel, Université Grenoble Alpes-CEA-CNRS, 38044 Grenoble, France
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, 52425 Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Alina Remeeva
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
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13
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Potekhina ES, Bass DY, Kelmanson IV, Fetisova ES, Ivanenko AV, Belousov VV, Bilan DS. Drug Screening with Genetically Encoded Fluorescent Sensors: Today and Tomorrow. Int J Mol Sci 2020; 22:E148. [PMID: 33375682 PMCID: PMC7794770 DOI: 10.3390/ijms22010148] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/18/2020] [Accepted: 12/24/2020] [Indexed: 02/07/2023] Open
Abstract
Genetically-encoded fluorescent sensors have been actively developed over the last few decades and used in live imaging and drug screening. Real-time monitoring of drug action in a specific cellular compartment, organ, or tissue type; the ability to screen at the single-cell resolution; and the elimination of false-positive results caused by low drug bioavailability that is not detected by in vitro testing methods are a few of the obvious benefits of using genetically-encoded fluorescent sensors in drug screening. In combination with high-throughput screening (HTS), some genetically-encoded fluorescent sensors may provide high reproducibility and robustness to assays. We provide a brief overview of successful, perspective, and hopeful attempts at using genetically encoded fluorescent sensors in HTS of modulators of ion channels, Ca2+ homeostasis, GPCR activity, and for screening cytotoxic, anticancer, and anti-parasitic compounds. We discuss the advantages of sensors in whole organism drug screening models and the perspectives of the combination of human disease modeling by CRISPR techniques with genetically encoded fluorescent sensors for drug screening.
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Affiliation(s)
- Ekaterina S. Potekhina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (D.Y.B.); (I.V.K.); (E.S.F.); (A.V.I.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Dina Y. Bass
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (D.Y.B.); (I.V.K.); (E.S.F.); (A.V.I.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Ilya V. Kelmanson
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (D.Y.B.); (I.V.K.); (E.S.F.); (A.V.I.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Elena S. Fetisova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (D.Y.B.); (I.V.K.); (E.S.F.); (A.V.I.); (V.V.B.)
| | - Alexander V. Ivanenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (D.Y.B.); (I.V.K.); (E.S.F.); (A.V.I.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Vsevolod V. Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (D.Y.B.); (I.V.K.); (E.S.F.); (A.V.I.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
- Federal Center of Brain Research and Neurotechnologies of the Federal Medical Biological Agency, 117997 Moscow, Russia
| | - Dmitry S. Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (D.Y.B.); (I.V.K.); (E.S.F.); (A.V.I.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
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FRCaMP, a Red Fluorescent Genetically Encoded Calcium Indicator Based on Calmodulin from Schizosaccharomyces Pombe Fungus. Int J Mol Sci 2020; 22:ijms22010111. [PMID: 33374320 PMCID: PMC7794825 DOI: 10.3390/ijms22010111] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
Red fluorescent genetically encoded calcium indicators (GECIs) have expanded the available pallet of colors used for the visualization of neuronal calcium activity in vivo. However, their calcium-binding domain is restricted by calmodulin from metazoans. In this study, we developed red GECI, called FRCaMP, using calmodulin (CaM) from Schizosaccharomyces pombe fungus as a calcium binding domain. Compared to the R-GECO1 indicator in vitro, the purified protein FRCaMP had similar spectral characteristics, brightness, and pH stability but a 1.3-fold lower ΔF/F calcium response and 2.6-fold tighter calcium affinity with Kd of 441 nM and 2.4-6.6-fold lower photostability. In the cytosol of cultured HeLa cells, FRCaMP visualized calcium transients with a ΔF/F dynamic range of 5.6, which was similar to that of R-GECO1. FRCaMP robustly visualized the spontaneous activity of neuronal cultures and had a similar ΔF/F dynamic range of 1.7 but 2.1-fold faster decay kinetics vs. NCaMP7. On electrically stimulated cultured neurons, FRCaMP demonstrated 1.8-fold faster decay kinetics and 1.7-fold lower ΔF/F values per one action potential of 0.23 compared to the NCaMP7 indicator. The fungus-originating CaM of the FRCaMP indicator version with a deleted M13-like peptide did not interact with the cytosolic environment of the HeLa cells in contrast to the metazoa-originating CaM of the similarly truncated version of the GCaMP6s indicator with a deleted M13-like peptide. Finally, we generated a split version of the FRCaMP indicator, which allowed the simultaneous detection of calcium transients and the heterodimerization of bJun/bFos interacting proteins in the nuclei of HeLa cells with a ΔF/F dynamic range of 9.4 and a contrast of 2.3-3.5, respectively.
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Subach OM, Subach FV. GAF-CaMP3-sfGFP, An Enhanced Version of the Near-Infrared Genetically Encoded Positive Phytochrome-Based Calcium Indicator for the Visualization of Neuronal Activity. Int J Mol Sci 2020; 21:ijms21186883. [PMID: 32961791 PMCID: PMC7555670 DOI: 10.3390/ijms21186883] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/20/2022] Open
Abstract
The first generation of near-infrared, genetically encoded calcium indicators (NIR-GECIs) was developed from bacterial phytochrome-based fluorescent proteins that utilize biliverdin (BV) as the chromophore moiety. However, NIR-GECIs have some main drawbacks such as either an inverted response to calcium ions (in the case of NIR-GECO1) or a limited dynamic range and a lack of data about their application in neurons (in the case of GAF-CaMP2–superfolder green fluorescent protein (sfGFP)). Here, we developed an enhanced version of the GAF-CaMP2–sfGFP indicator, named GAF-CaMP3–sfGFP. The GAF-CaMP3–sfGFP demonstrated spectral characteristics, molecular brightness, and a calcium affinity similar to the respective characteristics for its progenitor, but a 2.9-fold larger ΔF/F response to calcium ions. As compared to GAF-CaMP2–sfGFP, in cultured HeLa cells, GAF-CaMP3–sfGFP had similar brightness but a 1.9-fold larger ΔF/F response to the elevation of calcium ions levels. Finally, we successfully utilized the GAF-CaMP3–sfGFP for the monitoring of the spontaneous and stimulated activity of neuronal cultures and compared its performance with the R-GECO1 indicator using two-color confocal imaging. In the cultured neurons, GAF-CaMP3–sfGFP showed a linear ΔF/F response in the range of 0–20 APs and in this range demonstrated a 1.4-fold larger ΔF/F response but a 1.3- and 2.4-fold slower rise and decay kinetics, respectively, as compared to the same parameters for the R-GECO1 indicator.
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Affiliation(s)
- Oksana M. Subach
- Correspondence: (O.M.S.); (F.V.S.); Tel.: +07-499-196 7100-3389 (O.M.S. & F.V.S.)
| | - Fedor V. Subach
- Correspondence: (O.M.S.); (F.V.S.); Tel.: +07-499-196 7100-3389 (O.M.S. & F.V.S.)
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