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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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2
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Zhang Y, Looger LL. Fast and sensitive GCaMP calcium indicators for neuronal imaging. J Physiol 2024; 602:1595-1604. [PMID: 36811153 DOI: 10.1113/jp283832] [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: 11/20/2022] [Accepted: 02/15/2023] [Indexed: 02/24/2023] Open
Abstract
We review the principles of development and deployment of genetically encoded calcium indicators (GECIs) for the detection of neural activity. Our focus is on the popular GCaMP family of green GECIs, culminating in the recent release of the jGCaMP8 sensors, with dramatically improved kinetics relative to previous generations. We summarize the properties of GECIs in multiple colour channels (blue, cyan, green, yellow, red, far-red) and highlight areas for further improvement. With their low-millisecond rise-times, the jGCaMP8 indicators allow new classes of experiments following neural activity in time frames approaching the underlying computations.
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Affiliation(s)
- Yan Zhang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Loren L Looger
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA
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3
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Jensen GC, Janis MK, Jara J, Abbasi N, Zastrow ML. Zinc-Induced Fluorescence Turn-On in Native and Mutant Phycoerythrobilin-Binding Orange Fluorescent Proteins. Biochemistry 2023; 62:2828-2840. [PMID: 37699411 PMCID: PMC11057272 DOI: 10.1021/acs.biochem.3c00183] [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] [Indexed: 09/14/2023]
Abstract
Cyanobacteriochrome (CBCR)-derived fluorescent proteins are a class of reporters that can bind bilin cofactors and fluoresce across the ultraviolet to the near-infrared spectrum. Derived from phytochrome-related photoreceptor proteins in cyanobacteria, many of these proteins use a single small GAF domain to autocatalytically bind a bilin and fluoresce. The second GAF domain of All1280 (All1280g2) from Nostoc sp. PCC7120 is a DXCF motif-containing protein that exhibits blue-light-responsive photochemistry when bound to its native cofactor, phycocyanobilin. All1280g2 can also bind non-photoswitching phycoerythrobilin (PEB), resulting in a highly fluorescent protein. Given the small size, high quantum yield, and that unlike green fluorescent proteins, bilin-binding proteins can be used in anaerobic organisms, the orange fluorescent All1280g2-PEB protein is a promising platform for designing new genetically encoded metal ion sensors. Here, we show that All1280g2-PEB undergoes a ∼5-fold reversible zinc-induced fluorescence enhancement with a blue-shifted emission maximum (572 to 517 nm), which is not observed for a related PEB-bound GAF from Synechocystis sp. PCC6803 (Slr1393g3). Zn2+ significantly enhances All1280g2-PEB fluorescence across a biologically relevant pH range from 6.0 to 9.0, with pH-dependent dissociation constants from 1 μM to ∼20-80 nM. Site-directed mutants aiming to sterically decrease and increase access to PEB show a decreased and similar amount of zinc-induced fluorescence enhancement. Mutation of the cysteine residue within the DXCF motif to alanine abolishes the zinc-induced fluorescence enhancement. Collectively, these results support the presence of a unique fluorescence-enhancing Zn2+ binding site in All1280g2-PEB likely involving coordination to the bilin cofactor and requiring a nearby cysteine residue.
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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
| | - Jazzmin Jara
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Nasir Abbasi
- 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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4
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Lin C, Liu L, Zou P. Functional imaging-guided cell selection for evolving genetically encoded fluorescent indicators. CELL REPORTS METHODS 2023; 3:100544. [PMID: 37671014 PMCID: PMC10475787 DOI: 10.1016/j.crmeth.2023.100544] [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: 01/23/2023] [Revised: 06/05/2023] [Accepted: 07/06/2023] [Indexed: 09/07/2023]
Abstract
Genetically encoded fluorescent indicators are powerful tools for tracking cellular dynamic processes. Engineering these indicators requires balancing screening dimensions with screening throughput. Herein, we present a functional imaging-guided photoactivatable cell selection platform, Faculae (functional imaging-activated molecular evolution), for linking microscopic phenotype with the underlying genotype in a pooled mutant library. Faculae is capable of assessing tens of thousands of variants in mammalian cells simultaneously while achieving photoactivation with single-cell resolution in seconds. To demonstrate the feasibility of this approach, we applied Faculae to perform multidimensional directed evolution for far-red genetically encoded calcium indicators (FR-GECIs) with improved brightness (Nier1b) and signal-to-baseline ratio (Nier1s). We anticipate that this image-based pooled screening method will facilitate the development of a wide variety of biomolecular tools.
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Affiliation(s)
- Chang Lin
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing 100871, China
| | - Lihao Liu
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing 100871, China
| | - Peng Zou
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing 100871, China
- Academy for Advanced Interdisciplinary Studies, PKU-Tsinghua Center for Life Science, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
- Chinese Institute for Brain Research (CIBR), Beijing 102206, China
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5
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Abstract
The genetically encoded fluorescent sensors convert chemical and physical signals into light. They are powerful tools for the visualisation of physiological processes in living cells and freely moving animals. The fluorescent protein is the reporter module of a genetically encoded biosensor. In this study, we first review the history of the fluorescent protein in full emission spectra on a structural basis. Then, we discuss the design of the genetically encoded biosensor. Finally, we briefly review several major types of genetically encoded biosensors that are currently widely used based on their design and molecular targets, which may be useful for the future design of fluorescent biosensors.
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Affiliation(s)
- Minji Wang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhong Shan Road North, Shanghai, 200062, China
| | - Yifan Da
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhong Shan Road North, Shanghai, 200062, China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, No. 3663 Zhong Shan Road North, Shanghai, 200062, China
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6
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Hashizume R, Fujii H, Mehta S, Ota K, Qian Y, Zhu W, Drobizhev M, Nasu Y, Zhang J, Bito H, Campbell RE. A genetically encoded far-red fluorescent calcium ion biosensor derived from a biliverdin-binding protein. Protein Sci 2022; 31:e4440. [PMID: 36173169 PMCID: PMC9518226 DOI: 10.1002/pro.4440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 11/09/2022]
Abstract
Far-red and near-infrared (NIR) genetically encoded calcium ion (Ca2+ ) indicators (GECIs) are powerful tools for in vivo and multiplexed imaging of neural activity and cell signaling. Inspired by a previous report to engineer a far-red fluorescent protein (FP) from a biliverdin (BV)-binding NIR FP, we have developed a far-red fluorescent GECI, designated iBB-GECO1, from a previously reported NIR GECI. iBB-GECO1 exhibits a relatively high molecular brightness, an inverse response to Ca2+ with ΔF/Fmin = -13, and a near-optimal dissociation constant (Kd ) for Ca2+ of 105 nM. We demonstrate the utility of iBB-GECO1 for four-color multiplexed imaging in MIN6 cells and five-color imaging in HEK293T cells. Like other BV-binding GECIs, iBB-GECO1 did not give robust signals during in vivo imaging of neural activity in mice, but did provide promising results that will guide future engineering efforts. SIGNIFICANCE: Genetically encoded calcium ion (Ca2+ ) indicators (GECIs) compatible with common far-red laser lines (~630-640 nm) on commercial microscopes are of critical importance for their widespread application to deep-tissue multiplexed imaging of neural activity. In this study, we engineered a far-red excitable fluorescent GECI, designated iBB-GECO1, that exhibits a range of preferable specifications such as high brightness, large fluorescence response to Ca2+ , and compatibility with multiplexed imaging in mammalian cells.
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Affiliation(s)
- Rina Hashizume
- Department of Chemistry, School of ScienceThe University of Tokyo, Bunkyo‐kuTokyoJapan
| | - Hajime Fujii
- Department of Neurochemistry, Graduate School of MedicineThe University of Tokyo, Bunkyo‐kuTokyoJapan
| | - Sohum Mehta
- Department of PharmacologyUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Keisuke Ota
- Department of Neurochemistry, Graduate School of MedicineThe University of Tokyo, Bunkyo‐kuTokyoJapan
| | - Yong Qian
- Department of ChemistryUniversity of AlbertaEdmontonAlbertaCanada
- McGovern Institute for Brain Research, MITCambridgeMassachusettsUSA
| | - Wenchao Zhu
- Department of Chemistry, School of ScienceThe University of Tokyo, Bunkyo‐kuTokyoJapan
| | - Mikhail Drobizhev
- Department of Microbiology and Cell BiologyMontana State UniversityBozemanMontanaUSA
| | - Yusuke Nasu
- Department of Chemistry, School of ScienceThe University of Tokyo, Bunkyo‐kuTokyoJapan
| | - Jin Zhang
- Department of PharmacologyUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of MedicineThe University of Tokyo, Bunkyo‐kuTokyoJapan
| | - Robert E. Campbell
- Department of Chemistry, School of ScienceThe University of Tokyo, Bunkyo‐kuTokyoJapan
- Department of ChemistryUniversity of AlbertaEdmontonAlbertaCanada
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7
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LSSmScarlet2 and LSSmScarlet3, Chemically Stable Genetically Encoded Red Fluorescent Proteins with a Large Stokes’ Shift. Int J Mol Sci 2022; 23:ijms231911051. [PMID: 36232354 PMCID: PMC9569913 DOI: 10.3390/ijms231911051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 11/25/2022] Open
Abstract
Red fluorescent proteins with a large Stokes’ shift (LSSRFPs) are genetically encoded and efficiently excited by 488 nm light, allowing simultaneous dual-color one- and two-photon fluorescence imaging and fluorescence correlation spectroscopy in combination with green fluorescent proteins FPs. Recently, based on the conventional bright mScarlet RFP, we developed the LSSRFP LSSmScarlet. LSSmScarlet is characterized by two pKa values at pH values of 1.9 and 5.8. In this study, we developed improved versions of LSSmScarlet, named LSSmScarlet2 and LSSmScarlet3, which are characterized by a Stokes’ shift of 128 nm and extreme pH stability with a single pKa value of 2.2. LSSmScarlet2 and LSSmScarlet3 had 1.8-fold faster and 3-fold slower maturation than LSSmScarlet, respectively. In addition, both LSSRFPs were 1.5- to 1.6-fold more photostable and more chemically resistant to denaturation by guanidinium chloride and guanidinium thiocyanate. We also compared the susceptibility of the LSSmScarlet2, LSSmScarlet3, and other LSSRFPs to the reagents used for whole-mount imaging, expansion microscopy, and immunostaining techniques. Due to higher pH stability and faster maturation, the LSSmScarlet3-LAMP3 fusion was 2.2-fold brighter than LSSmScarlet-LAMP3 in lysosomes of mammalian cells. The LSSmScarlet3-hLAMP2A fusion was similar in brightness to LSSmScarlet-hLAMP2A in lysosomes. We successfully applied the monomeric LSSmScarlet2 and LSSmScarlet3 proteins for confocal imaging of structural proteins in live mammalian cells. We also solved the X-ray structure of the LSSmScarlet2 protein at a resolution of 1.41 Å. Site-directed mutagenesis of the LSSmScarlet2 protein demonstrated the key role of the T74 residue in improving the pH and chemical stability of the LSSmScarlet2 protein.
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8
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Dual-expression system for blue fluorescent protein optimization. Sci Rep 2022; 12:10190. [PMID: 35715437 PMCID: PMC9206027 DOI: 10.1038/s41598-022-13214-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 05/23/2022] [Indexed: 11/08/2022] Open
Abstract
Spectrally diverse fluorescent proteins (FPs) provide straightforward means for multiplexed imaging of biological systems. Among FPs fitting standard color channels, blue FPs (BFPs) are characterized by lower brightness compared to other spectral counterparts. Furthermore, available BFPs were not systematically characterized for imaging in cultured mammalian cells and common model organisms. Here we introduce a pair of new BFPs, named Electra1 and Electra2, developed through hierarchical screening in bacterial and mammalian cells using a novel dual-expression vector. We performed systematic benchmarking of Electras against state-of-art BFPs in cultured mammalian cells and demonstrated their utility as fluorescent tags for structural proteins. The Electras variants were validated for multicolor neuroimaging in Caenorhabditis elegans, zebrafish larvae, and mice in comparison with one of the best in the class BFP mTagBFP2 using one-photon and two-photon microscopy. The developed BFPs are suitable for multicolor imaging of cultured cells and model organisms in vivo. We believe that the described dual-expression vector has a great potential to be adopted by protein engineers for directed molecular evolution of FPs.
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9
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Genetically encoded photo-switchable molecular sensors for optoacoustic and super-resolution imaging. Nat Biotechnol 2022; 40:598-605. [PMID: 34845372 PMCID: PMC9005348 DOI: 10.1038/s41587-021-01100-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/17/2021] [Indexed: 02/07/2023]
Abstract
Reversibly photo-switchable proteins are essential for many super-resolution fluorescence microscopic and optoacoustic imaging methods. However, they have yet to be used as sensors that measure the distribution of specific analytes at the nanoscale or in the tissues of live animals. Here we constructed the prototype of a photo-switchable Ca2+ sensor based on GCaMP5G that can be switched with 405/488-nm light and describe its molecular mechanisms at the structural level, including the importance of the interaction of the core barrel structure of the fluorescent protein with the Ca2+ receptor moiety. We demonstrate super-resolution imaging of Ca2+ concentration in cultured cells and optoacoustic Ca2+ imaging in implanted tumor cells in mice under controlled Ca2+ conditions. Finally, we show the generalizability of the concept by constructing examples of photo-switching maltose and dopamine sensors based on periplasmatic binding protein and G-protein-coupled receptor-based sensors.
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10
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Tang K, Beyer HM, Zurbriggen MD, Gärtner W. The Red Edge: Bilin-Binding Photoreceptors as Optogenetic Tools and Fluorescence Reporters. Chem Rev 2021; 121:14906-14956. [PMID: 34669383 PMCID: PMC8707292 DOI: 10.1021/acs.chemrev.1c00194] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Indexed: 12/15/2022]
Abstract
This review adds the bilin-binding phytochromes to the Chemical Reviews thematic issue "Optogenetics and Photopharmacology". The work is structured into two parts. We first outline the photochemistry of the covalently bound tetrapyrrole chromophore and summarize relevant spectroscopic, kinetic, biochemical, and physiological properties of the different families of phytochromes. Based on this knowledge, we then describe the engineering of phytochromes to further improve these chromoproteins as photoswitches and review their employment in an ever-growing number of different optogenetic applications. Most applications rely on the light-controlled complex formation between the plant photoreceptor PhyB and phytochrome-interacting factors (PIFs) or C-terminal light-regulated domains with enzymatic functions present in many bacterial and algal phytochromes. Phytochrome-based optogenetic tools are currently implemented in bacteria, yeast, plants, and animals to achieve light control of a wide range of biological activities. These cover the regulation of gene expression, protein transport into cell organelles, and the recruitment of phytochrome- or PIF-tagged proteins to membranes and other cellular compartments. This compilation illustrates the intrinsic advantages of phytochromes compared to other photoreceptor classes, e.g., their bidirectional dual-wavelength control enabling instant ON and OFF regulation. In particular, the long wavelength range of absorption and fluorescence within the "transparent window" makes phytochromes attractive for complex applications requiring deep tissue penetration or dual-wavelength control in combination with blue and UV light-sensing photoreceptors. In addition to the wide variability of applications employing natural and engineered phytochromes, we also discuss recent progress in the development of bilin-based fluorescent proteins.
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Affiliation(s)
- Kun Tang
- Institute
of Synthetic Biology, Heinrich-Heine-University
Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
| | - Hannes M. Beyer
- Institute
of Synthetic Biology, Heinrich-Heine-University
Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
| | - Matias D. Zurbriggen
- Institute
of Synthetic Biology and CEPLAS, Heinrich-Heine-University
Düsseldorf, Universitätsstrasse
1, D-40225 Düsseldorf, Germany
| | - Wolfgang Gärtner
- Retired: Max Planck Institute
for Chemical Energy Conversion. At present: Institute for Analytical Chemistry, University
Leipzig, Linnéstrasse
3, 04103 Leipzig, Germany
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11
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Subach OM, Vlaskina AV, Agapova YK, Dorovatovskii PV, Nikolaeva AY, Ivashkina OI, Popov VO, Piatkevich KD, Khrenova MG, Smirnova TA, Boyko KM, Subach FV. LSSmScarlet, dCyRFP2s, dCyOFP2s and CRISPRed2s, Genetically Encoded Red Fluorescent Proteins with a Large Stokes Shift. Int J Mol Sci 2021; 22:12887. [PMID: 34884694 PMCID: PMC8657457 DOI: 10.3390/ijms222312887] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/20/2021] [Accepted: 11/24/2021] [Indexed: 11/24/2022] Open
Abstract
Genetically encoded red fluorescent proteins with a large Stokes shift (LSSRFPs) can be efficiently co-excited with common green FPs both under single- and two-photon microscopy, thus enabling dual-color imaging using a single laser. Recent progress in protein development resulted in a great variety of novel LSSRFPs; however, the selection of the right LSSRFP for a given application is hampered by the lack of a side-by-side comparison of the LSSRFPs' performance. In this study, we employed rational design and random mutagenesis to convert conventional bright RFP mScarlet into LSSRFP, called LSSmScarlet, characterized by excitation/emission maxima at 470/598 nm. In addition, we utilized the previously reported LSSRFPs mCyRFP1, CyOFP1, and mCRISPRed as templates for directed molecular evolution to develop their optimized versions, called dCyRFP2s, dCyOFP2s and CRISPRed2s. We performed a quantitative assessment of the developed LSSRFPs and their precursors in vitro on purified proteins and compared their brightness at 488 nm excitation in the mammalian cells. The monomeric LSSmScarlet protein was successfully utilized for the confocal imaging of the structural proteins in live mammalian cells and multicolor confocal imaging in conjugation with other FPs. LSSmScarlet was successfully applied for dual-color two-photon imaging in live mammalian cells. We also solved the X-ray structure of the LSSmScarlet protein at the resolution of 1.4 Å that revealed a hydrogen bond network supporting excited-state proton transfer (ESPT). Quantum mechanics/molecular mechanics molecular dynamic simulations confirmed the ESPT mechanism of a large Stokes shift. Structure-guided mutagenesis revealed the role of R198 residue in ESPT that allowed us to generate a variant with improved pH stability. Finally, we showed that LSSmScarlet protein is not appropriate for STED microscopy as a consequence of LSSRed-to-Red photoconversion with high-power 775 nm depletion light.
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Affiliation(s)
- Oksana M. Subach
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
| | - Anna V. Vlaskina
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
| | - Yuliya K. Agapova
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
| | - Pavel V. Dorovatovskii
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
| | - Alena Y. Nikolaeva
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (M.G.K.); (K.M.B.)
| | - Olga I. Ivashkina
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
- Laboratory for Neurobiology of Memory, P.K. Anokhin Research Institute of Normal Physiology, 125315 Moscow, Russia
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Vladimir O. Popov
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (M.G.K.); (K.M.B.)
- Faculty of Biology, M.V. Lomonosov Moscow State University, 119991 Moscow, 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
| | - Maria G. Khrenova
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (M.G.K.); (K.M.B.)
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Tatiana A. Smirnova
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia;
| | - Konstantin M. Boyko
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (M.G.K.); (K.M.B.)
| | - Fedor V. Subach
- Complex of NBICS Technologies, National Research Center “Kurchatov Institute”, 123182 Moscow, Russia; (O.M.S.); (A.V.V.); (Y.K.A.); (P.V.D.); (A.Y.N.); (O.I.I.); (V.O.P.)
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12
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Shcherbakova DM. Near-infrared and far-red genetically encoded indicators of neuronal activity. J Neurosci Methods 2021; 362:109314. [PMID: 34375713 DOI: 10.1016/j.jneumeth.2021.109314] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/15/2021] [Accepted: 08/05/2021] [Indexed: 12/18/2022]
Abstract
Genetically encoded fluorescent indicators of neuronal activity are ultimately developed to dissect functions of neuronal ensembles during behavior in living animals. Recent development of near-infrared shifted calcium and voltage indicators moved us closer to this goal and enabled crosstalk-free combination with blue light-controlled optogenetic tools for all-optical control and readout. Here I discuss designs of recent near-infrared and far-red calcium and voltage indicators, compare their properties and performance, and overview their applications to spectral multiplexing and in vivo imaging. I also provide perspectives for further development.
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Affiliation(s)
- Daria M Shcherbakova
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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13
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Bodea SV, Westmeyer GG. Photoacoustic Neuroimaging - Perspectives on a Maturing Imaging Technique and its Applications in Neuroscience. Front Neurosci 2021; 15:655247. [PMID: 34220420 PMCID: PMC8253050 DOI: 10.3389/fnins.2021.655247] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/08/2021] [Indexed: 11/13/2022] Open
Abstract
A prominent goal of neuroscience is to improve our understanding of how brain structure and activity interact to produce perception, emotion, behavior, and cognition. The brain's network activity is inherently organized in distinct spatiotemporal patterns that span scales from nanometer-sized synapses to meter-long nerve fibers and millisecond intervals between electrical signals to decades of memory storage. There is currently no single imaging method that alone can provide all the relevant information, but intelligent combinations of complementary techniques can be effective. Here, we thus present the latest advances in biomedical and biological engineering on photoacoustic neuroimaging in the context of complementary imaging techniques. A particular focus is placed on recent advances in whole-brain photoacoustic imaging in rodent models and its influential role in bridging the gap between fluorescence microscopy and more non-invasive techniques such as magnetic resonance imaging (MRI). We consider current strategies to address persistent challenges, particularly in developing molecular contrast agents, and conclude with an overview of potential future directions for photoacoustic neuroimaging to provide deeper insights into healthy and pathological brain processes.
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Affiliation(s)
- Silviu-Vasile Bodea
- Department of Chemistry and School of Medicine, Technical University of Munich (TUM), Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Center Munich, Munich, Germany
| | - Gil Gregor Westmeyer
- Department of Chemistry and School of Medicine, Technical University of Munich (TUM), Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Center Munich, Munich, Germany
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14
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Li ES, Saha MS. Optimizing Calcium Detection Methods in Animal Systems: A Sandbox for Synthetic Biology. Biomolecules 2021; 11:343. [PMID: 33668387 PMCID: PMC7996158 DOI: 10.3390/biom11030343] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 12/16/2022] Open
Abstract
Since the 1970s, the emergence and expansion of novel methods for calcium ion (Ca2+) detection have found diverse applications in vitro and in vivo across a series of model animal systems. Matched with advances in fluorescence imaging techniques, the improvements in the functional range and stability of various calcium indicators have significantly enhanced more accurate study of intracellular Ca2+ dynamics and its effects on cell signaling, growth, differentiation, and regulation. Nonetheless, the current limitations broadly presented by organic calcium dyes, genetically encoded calcium indicators, and calcium-responsive nanoparticles suggest a potential path toward more rapid optimization by taking advantage of a synthetic biology approach. This engineering-oriented discipline applies principles of modularity and standardization to redesign and interrogate endogenous biological systems. This review will elucidate how novel synthetic biology technologies constructed for eukaryotic systems can offer a promising toolkit for interfacing with calcium signaling and overcoming barriers in order to accelerate the process of Ca2+ detection optimization.
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Affiliation(s)
| | - Margaret S. Saha
- Department of Biology, College of William and Mary, Williamsburg, VA 23185, USA;
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15
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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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16
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Camarca A, Varriale A, Capo A, Pennacchio A, Calabrese A, Giannattasio C, Murillo Almuzara C, D’Auria S, Staiano M. Emergent Biosensing Technologies Based on Fluorescence Spectroscopy and Surface Plasmon Resonance. SENSORS (BASEL, SWITZERLAND) 2021; 21:906. [PMID: 33572812 PMCID: PMC7866296 DOI: 10.3390/s21030906] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/23/2022]
Abstract
The purpose of this work is to provide an exhaustive overview of the emerging biosensor technologies for the detection of analytes of interest for food, environment, security, and health. Over the years, biosensors have acquired increasing importance in a wide range of applications due to synergistic studies of various scientific disciplines, determining their great commercial potential and revealing how nanotechnology and biotechnology can be strictly connected. In the present scenario, biosensors have increased their detection limit and sensitivity unthinkable until a few years ago. The most widely used biosensors are optical-based devices such as surface plasmon resonance (SPR)-based biosensors and fluorescence-based biosensors. Here, we will review them by highlighting how the progress in their design and development could impact our daily life.
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Affiliation(s)
- Alessandra Camarca
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
| | - Antonio Varriale
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
- URT-ISA at Department of Biology, University of Naples Federico II, 80126 Napoli, Italy
| | - Alessandro Capo
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
| | - Angela Pennacchio
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
| | - Alessia Calabrese
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
| | - Cristina Giannattasio
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
| | - Carlos Murillo Almuzara
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
| | - Sabato D’Auria
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
| | - Maria Staiano
- Institute of Food Science, CNR Italy, 83100 Avellino, Italy; (A.C.); (A.V.); (A.C.); (A.P.); (A.C.); (C.G.); (C.M.A.); (M.S.)
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17
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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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18
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Qian Y, Cosio DMO, Piatkevich KD, Aufmkolk S, Su WC, Celiker OT, Schohl A, Murdock MH, Aggarwal A, Chang YF, Wiseman PW, Ruthazer ES, Boyden ES, Campbell RE. Improved genetically encoded near-infrared fluorescent calcium ion indicators for in vivo imaging. PLoS Biol 2020; 18:e3000965. [PMID: 33232322 PMCID: PMC7723245 DOI: 10.1371/journal.pbio.3000965] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 12/08/2020] [Accepted: 10/29/2020] [Indexed: 12/15/2022] Open
Abstract
Near-infrared (NIR) genetically encoded calcium ion (Ca2+) indicators (GECIs) can provide advantages over visible wavelength fluorescent GECIs in terms of reduced phototoxicity, minimal spectral cross talk with visible light excitable optogenetic tools and fluorescent probes, and decreased scattering and absorption in mammalian tissues. Our previously reported NIR GECI, NIR-GECO1, has these advantages but also has several disadvantages including lower brightness and limited fluorescence response compared to state-of-the-art visible wavelength GECIs, when used for imaging of neuronal activity. Here, we report 2 improved NIR GECI variants, designated NIR-GECO2 and NIR-GECO2G, derived from NIR-GECO1. We characterized the performance of the new NIR GECIs in cultured cells, acute mouse brain slices, and Caenorhabditis elegans and Xenopus laevis in vivo. Our results demonstrate that NIR-GECO2 and NIR-GECO2G provide substantial improvements over NIR-GECO1 for imaging of neuronal Ca2+ dynamics. This study describes improved genetically encoded near-infrared fluorescent calcium ion indicators, demonstrating that they enable robust detection of neuronal activity in cultured cells, rodent brain slices, Caenorhabditis elegans, and Xenopus laevis.
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Affiliation(s)
- Yong Qian
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
- Departments of Biological Engineering, Media Arts and Sciences, Brain and Cognitive Sciences, McGovern Institute, Koch Institute, Center for Neurobiological Engineering, MIT, and Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
| | - Danielle M. Orozco Cosio
- Departments of Biological Engineering, Media Arts and Sciences, Brain and Cognitive Sciences, McGovern Institute, Koch Institute, Center for Neurobiological Engineering, MIT, and Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
| | - Kiryl D. Piatkevich
- Departments of Biological Engineering, Media Arts and Sciences, Brain and Cognitive Sciences, McGovern Institute, Koch Institute, Center for Neurobiological Engineering, MIT, and Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
- School of Life Sciences, Westlake University, Hangzhou, China
| | - Sarah Aufmkolk
- Montreal Neurological Institute-Hospital, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Wan-Chi Su
- LumiSTAR Biotechnology, Nangang District, Taipei City, Taiwan
| | - Orhan T. Celiker
- Departments of Biological Engineering, Media Arts and Sciences, Brain and Cognitive Sciences, McGovern Institute, Koch Institute, Center for Neurobiological Engineering, MIT, and Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
| | - Anne Schohl
- Montreal Neurological Institute-Hospital, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Mitchell H. Murdock
- Departments of Biological Engineering, Media Arts and Sciences, Brain and Cognitive Sciences, McGovern Institute, Koch Institute, Center for Neurobiological Engineering, MIT, and Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
| | - Abhi Aggarwal
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States of America
| | - Yu-Fen Chang
- LumiSTAR Biotechnology, Nangang District, Taipei City, Taiwan
| | - Paul W. Wiseman
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
- Department of Physics, McGill University, Montreal, Quebec, Canada
| | - Edward S. Ruthazer
- Montreal Neurological Institute-Hospital, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Edward S. Boyden
- Departments of Biological Engineering, Media Arts and Sciences, Brain and Cognitive Sciences, McGovern Institute, Koch Institute, Center for Neurobiological Engineering, MIT, and Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
| | - Robert E. Campbell
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
- Department of Chemistry, The University of Tokyo, Tokyo, Japan
- * E-mail:
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19
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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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20
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Broch F, Gautier A. Illuminating Cellular Biochemistry: Fluorogenic Chemogenetic Biosensors for Biological Imaging. Chempluschem 2020; 85:1487-1497. [PMID: 32644262 DOI: 10.1002/cplu.202000413] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/18/2020] [Indexed: 12/19/2022]
Abstract
Cellular activity is defined by the precise spatiotemporal regulation of various components, such as ions, small molecules, or proteins. Studying cell physiology consequently requires the optical recording of these processes, notably by using fluorescent biosensors. The recent development of various fluorogenic systems greatly expanded the palette of reporters to be included in these sensors design. Fluorogenic reporters consist of a protein or RNA tag that can complex either an endogenous or a synthetic fluorogenic dye (so-called fluorogen). The intrinsic nature of these tags, along with the high tunability of their cognate chromophore provide interesting features such as far-red to near-infrared emission, oxygen independence, or unprecedented color versatility. These engineered photoreceptors, self-labelling proteins, or noncovalent aptamers and protein tags were rapidly identified as promising reporters to observe biological events. This Minireview focuses on the new perspectives they offer to design unique and innovative biosensors, thus pushing the boundaries of cellular imaging.
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Affiliation(s)
- Fanny Broch
- Sorbonne Université, École normale supérieure, PSL University, CNRS Laboratoire des biomolécules, LBM, 75005, Paris, France
| | - Arnaud Gautier
- Sorbonne Université, École normale supérieure, PSL University, CNRS Laboratoire des biomolécules, LBM, 75005, Paris, France.,Institut Universitaire de France, France
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21
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Tang S, Deng X, Jiang J, Kirberger M, Yang JJ. Design of Calcium-Binding Proteins to Sense Calcium. Molecules 2020; 25:molecules25092148. [PMID: 32375353 PMCID: PMC7248937 DOI: 10.3390/molecules25092148] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 01/25/2023] Open
Abstract
Calcium controls numerous biological processes by interacting with different classes of calcium binding proteins (CaBP’s), with different affinities, metal selectivities, kinetics, and calcium dependent conformational changes. Due to the diverse coordination chemistry of calcium, and complexity associated with protein folding and binding cooperativity, the rational design of CaBP’s was anticipated to present multiple challenges. In this paper we will first discuss applications of statistical analysis of calcium binding sites in proteins and subsequent development of algorithms to predict and identify calcium binding proteins. Next, we report efforts to identify key determinants for calcium binding affinity, cooperativity and calcium dependent conformational changes using grafting and protein design. Finally, we report recent advances in designing protein calcium sensors to capture calcium dynamics in various cellular environments.
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Affiliation(s)
- Shen Tang
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
| | - Xiaonan Deng
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
| | - Jie Jiang
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
| | - Michael Kirberger
- School of Science and Technology, Georgia Gwinnett College, Lawrenceville, GA 30043, USA;
| | - Jenny J. Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics and Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA; (S.T.); (X.D.); (J.J.)
- Correspondence: ; Tel.: +1-404-413-5520
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22
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Ravotto L, Duffet L, Zhou X, Weber B, Patriarchi T. A Bright and Colorful Future for G-Protein Coupled Receptor Sensors. Front Cell Neurosci 2020; 14:67. [PMID: 32265667 PMCID: PMC7098945 DOI: 10.3389/fncel.2020.00067] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/05/2020] [Indexed: 01/07/2023] Open
Abstract
Neurochemicals have a large impact on brain states and animal behavior but are notoriously hard to detect accurately in the living brain. Recently developed genetically encoded sensors obtained from engineering a circularly permuted green fluorescent protein into G-protein coupled receptors (GPCR) provided a vital boost to neuroscience, by innovating the way we monitor neural communication. These new probes are becoming widely successful due to their flexible combination with state of the art optogenetic tools and in vivo imaging techniques, mainly fiber photometry and 2-photon microscopy, to dissect dynamic changes in brain chemicals with unprecedented spatial and temporal resolution. Here, we highlight current approaches and challenges as well as novel insights in the process of GPCR sensor development, and discuss possible future directions of the field.
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Affiliation(s)
- Luca Ravotto
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Loïc Duffet
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Xuehan Zhou
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, Zurich, Switzerland
| | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, Zurich, Switzerland
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23
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Subach OM, Sotskov VP, Plusnin VV, Gruzdeva AM, Barykina NV, Ivashkina OI, Anokhin KV, Nikolaeva AY, Korzhenevskiy DA, Vlaskina AV, Lazarenko VA, Boyko KM, Rakitina TV, Varizhuk AM, Pozmogova GE, Podgorny OV, Piatkevich KD, Boyden ES, Subach FV. Novel Genetically Encoded Bright Positive Calcium Indicator NCaMP7 Based on the mNeonGreen Fluorescent Protein. Int J Mol Sci 2020; 21:ijms21051644. [PMID: 32121243 PMCID: PMC7084697 DOI: 10.3390/ijms21051644] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 02/25/2020] [Accepted: 02/25/2020] [Indexed: 12/21/2022] Open
Abstract
Green fluorescent genetically encoded calcium indicators (GECIs) are the most popular tool for visualization of calcium dynamics in vivo. However, most of them are based on the EGFP protein and have similar molecular brightnesses. The NTnC indicator, which is composed of the mNeonGreen fluorescent protein with the insertion of troponin C, has higher brightness as compared to EGFP-based GECIs, but shows a limited inverted response with an ΔF/F of 1. By insertion of a calmodulin/M13-peptide pair into the mNeonGreen protein, we developed a green GECI called NCaMP7. In vitro, NCaMP7 showed positive response with an ΔF/F of 27 and high affinity (Kd of 125 nM) to calcium ions. NCaMP7 demonstrated a 1.7-fold higher brightness and similar calcium-association/dissociation dynamics compared to the standard GCaMP6s GECI in vitro. According to fluorescence recovery after photobleaching (FRAP) experiments, the NCaMP7 design partially prevented interactions of NCaMP7 with the intracellular environment. The NCaMP7 crystal structure was obtained at 1.75 Å resolution to uncover the molecular basis of its calcium ions sensitivity. The NCaMP7 indicator retained a high and fast response when expressed in cultured HeLa and neuronal cells. Finally, we successfully utilized the NCaMP7 indicator for in vivo visualization of grating-evoked and place-dependent neuronal activity in the visual cortex and the hippocampus of mice using a two-photon microscope and an NVista miniscope, respectively.
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Affiliation(s)
- Oksana M. Subach
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
| | - Vladimir P. Sotskov
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, Moscow 119991, Russia; (V.P.S.); (K.V.A.)
| | - Viktor V. Plusnin
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
| | - Anna M. Gruzdeva
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, Moscow 119991, Russia; (V.P.S.); (K.V.A.)
| | - Natalia V. Barykina
- P.K. Anokhin Research Institute of Normal Physiology, Moscow 125315, Russia;
| | - Olga I. Ivashkina
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, Moscow 119991, Russia; (V.P.S.); (K.V.A.)
- P.K. Anokhin Research Institute of Normal Physiology, Moscow 125315, Russia;
| | - Konstantin V. Anokhin
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, Moscow 119991, Russia; (V.P.S.); (K.V.A.)
- P.K. Anokhin Research Institute of Normal Physiology, Moscow 125315, Russia;
| | - Alena Y. Nikolaeva
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
| | - Dmitry A. Korzhenevskiy
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
| | - Anna V. Vlaskina
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
| | - Vladimir A. Lazarenko
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
| | - Konstantin M. Boyko
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia;
| | - Tatiana V. Rakitina
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow 117997, Russia;
| | - Anna M. Varizhuk
- Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia; (A.M.V.); (G.E.P.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Moscow 119435, Russia
| | - Galina E. Pozmogova
- Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia; (A.M.V.); (G.E.P.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Moscow 119435, Russia
| | - Oleg V. Podgorny
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow 117997, Russia;
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow 117997, Russia
- N.K. Koltzov Institute of Developmental Biology, RAS, Moscow 119334, Russia
| | - Kiryl D. Piatkevich
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA; (K.D.P.); (E.S.B.)
- School of Life Sciences, Westlake University, Hangzhou 310024, China
| | - Edward S. Boyden
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA; (K.D.P.); (E.S.B.)
| | - Fedor V. Subach
- National Research Center “Kurchatov Institute”, Moscow 123182, Russia; (O.M.S.); (V.V.P.); (A.M.G.); (O.I.I.); (A.Y.N.); (D.A.K.); (A.V.V.); (V.A.L.); (T.V.R.)
- Correspondence: ; Tel.: +07-499-196 7100-3389
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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