1
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Aono Y, Nakajima T, Ichimiya W, Yoshida M, Sato M. Highly Efficient Fluorescent Probe to Visualize Protein Interactions at the Superresolution. ACS Chem Biol 2024. [PMID: 38835147 DOI: 10.1021/acschembio.4c00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Superresolution microscopy (SR microscopy) of protein-protein interactions (PPIs) occurring in subcellular structures is essential for understanding cellular functions. However, a powerful and useful technology for SR microscopy of PPIs remains elusive. Here, we develop a highly efficient photoconvertible fluorescent probe, named split-Dendra2, for SR microscopy of PPIs in the cell. We found that split-Dendra2 enables a highly efficient detection of PPIs, making it possible to perform SR microscopy of PPIs with high spatial resolution and high image reconstruction fidelity. We demonstrate the utility of split-Dendra2 by visualizing PPIs occurring in small subcellular structures at the superresolution, such as clathrin-coated pits and focal adhesions, which cannot be visualized by the existing tools. Split-Dendra2 offers a powerful and useful tool that greatly expands the possibility of SR microscopy and can contribute to revealing the function of PPIs at the nanoscale resolution.
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Affiliation(s)
- Yuki Aono
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Takahiro Nakajima
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
- Kanagawa Institute of Industrial Science and Technology, Kanagawa 243-0435, Japan
| | - Wataru Ichimiya
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Mayumi Yoshida
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Moritoshi Sato
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
- Kanagawa Institute of Industrial Science and Technology, Kanagawa 243-0435, Japan
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2
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Purkait D, Ilyas M, Atmakuri K. Protein-Protein Interactions: Bimolecular Fluorescence Complementation and Cytology Two Hybrid. Methods Mol Biol 2024; 2715:247-257. [PMID: 37930533 DOI: 10.1007/978-1-0716-3445-5_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Identifying protein-protein interactions between machine components of bacterial secretion systems and their cognate substrates is central to delineating how the machines operate to translocate their substrates. Further, establishing which among the machine components and their substrates interact with each other facilitates (i) advancement in our understanding of the architecture and assembly of the machines, (ii) understanding the substrates' translocation routes and mechanisms, and (iii) how the machines and the substrates talk to each other. Currently, though diverse biochemical methods exist in identifying direct and indirect protein-protein interactions, they primarily remain in vitro and can be quite labor intensive. They also may capture/exhibit false-positive interactions because of barrier breakdowns as part of methodology. Thus, adopting novel genetic approaches to help visualize the same in vivo can yield quick, advantageous, reliable, and informative protein-protein interactions data. Here, we describe the easily adoptable bimolecular fluorescence complementation and cytology-based two-hybrid assays to understand the bacterial secretions systems.
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Affiliation(s)
- Dyuti Purkait
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Mohd Ilyas
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Krishnamohan Atmakuri
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India.
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3
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Zhu YH, Liu XX, Fang Q, Liu XY, Fang WH, Cui G. Multiple Photoisomerization Pathways of the Green Fluorescent Protein Chromophore in a Reversibly Photoswitchable Fluorescent Protein: Insights from Quantum Mechanics/Molecular Mechanics Simulations. J Phys Chem Lett 2023; 14:2588-2598. [PMID: 36881005 DOI: 10.1021/acs.jpclett.3c00165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Herein, we have employed a combined CASPT2//CASSCF approach within the quantum mechanics/molecular mechanics (QM/MM) framework to explore the early time photoisomerization of rsEGFP2 starting from its two OFF trans states, i.e., Trans1 and Trans2. The results show similar vertical excitation energies to the S1 state in their Franck-Condon regions. Considering the clockwise and counterclockwise rotations of the C11-C9 bond, four pairs of the S1 excited-state minima and low-lying S1/S0 conical intersections were optimized, based on which we determined four S1 photoisomerization paths that are essentially barrierless to the relevant S1/S0 conical intersections leading to efficient excited-state deactivation to the S0 state. Most importantly, our work first identified multiple photoisomerization and excited-state decay paths, which must be seriously considered in the future. This work not only sheds significant light on the primary trans-cis photoisomerization of rsEGFP2 but also aids in the understanding of the microscopic mechanism of GFP-like RSFPs and the design of novel GFP-like fluorescent proteins.
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Affiliation(s)
- Yun-Hua Zhu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xin-Xin Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Qiu Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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4
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Auer JMT, Murphy LC, Xiao D, Li DU, Wheeler AP. Non-fitting FLIM-FRET facilitates analysis of protein interactions in live zebrafish embryos. J Microsc 2022. [PMID: 36448983 DOI: 10.1111/jmi.13162] [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: 09/12/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022]
Abstract
Molecular interactions are key to all cellular processes, and particularly interesting to investigate in the context of gene regulation. Protein-protein interactions are challenging to examine in vivo as they are dynamic, and require spatially and temporally resolved studies to interrogate them. Foerster Resonance Energy Transfer (FRET) is a highly sensitive imaging method, which can interrogate molecular interactions. FRET can be detected by Fluorescence Lifetime Imaging Microscopy (FLIM-FRET), which is more robust to concentration variations and photobleaching than intensity-based FRET but typically needs long acquisition times to achieve high photon counts. New variants of non-fitting lifetime-based FRET perform well in samples with lower signal and require less intensive instrument calibration and analysis, making these methods ideal for probing protein-protein interactions in more complex live 3D samples. Here we show that a non-fitting FLIM-FRET variant, based on the Average Arrival Time of photons per pixel (AAT- FRET), is a sensitive and simple way to detect and measure protein-protein interactions in live early stage zebrafish embryos.
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Affiliation(s)
- Julia M T Auer
- MRC Human Genetics Unit, Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
| | - Laura C Murphy
- MRC Human Genetics Unit, Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
| | - Dong Xiao
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - David U Li
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - Ann P Wheeler
- MRC Human Genetics Unit, Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
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5
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Zhou K, Litfin T, Solayman M, Zhao H, Zhou Y, Zhan J. High-throughput split-protein profiling by combining transposon mutagenesis and regulated protein-protein interactions with deep sequencing. Int J Biol Macromol 2022; 203:543-552. [PMID: 35120933 DOI: 10.1016/j.ijbiomac.2022.01.173] [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: 08/02/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 11/05/2022]
Abstract
Splitting a protein at a position may lead to self- or assisted-complementary fragments depending on whether two resulting fragments can reconstitute to maintain the native function spontaneously or require assistance from two interacting molecules. Assisted complementary fragments with high contrast are an important tool for probing biological interactions. However, only a small number of assisted-complementary split-variants have been identified due to manual, labour-intensive optimization of a candidate gene. Here, we introduce a technique for high-throughput split-protein profiling (HiTS) that allows fast identification of self- and assisted complementary positions by transposon mutagenesis, a rapamycin-regulated FRB-FKBP protein interaction pair, and deep sequencing. We test this technique by profiling three antibiotic-resistant genes (fosfomycin-resistant gene, fosA3, erythromycin-resistant gene, ermB, and chloramphenicol-resistant gene, catI). Self- and assisted complementary fragments discovered by the high-throughput technique were subsequently confirmed by low-throughput testing of individual split positions. Thus, the HiTS technique provides a quicker alternative for discovering the proteins with suitable self- and assisted-complementary split positions when combining with a readout such as fluorescence, bioluminescence, cell survival, gene transcription or genome editing.
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Affiliation(s)
- Kai Zhou
- Institute for Glycomics and School of Information and Communication Technology, Griffith University, Parklands Dr Southport, QLD 4222, Australia; Institute for Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
| | - Thomas Litfin
- Institute for Glycomics and School of Information and Communication Technology, Griffith University, Parklands Dr Southport, QLD 4222, Australia
| | - Md Solayman
- Institute for Glycomics and School of Information and Communication Technology, Griffith University, Parklands Dr Southport, QLD 4222, Australia
| | - Huijun Zhao
- Centre for Clean Environment and Energy, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Yaoqi Zhou
- Institute for Glycomics and School of Information and Communication Technology, Griffith University, Parklands Dr Southport, QLD 4222, Australia; Institute for Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China.
| | - Jian Zhan
- Institute for Glycomics and School of Information and Communication Technology, Griffith University, Parklands Dr Southport, QLD 4222, Australia; Institute for Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China.
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6
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Sun Y, Wang Y, Chen K, Sun Y, Wang S. Rational engineering and synthetic applications of a high specificity BiFC probe derived from Springgreen-M. Analyst 2022; 147:4326-4336. [DOI: 10.1039/d2an01124g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A high signal-to-noise (S/N) ratio BiFC assay was developed for efficient detection and flexible visualization of protein–protein interactions under physiological conditions in live cells.
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Affiliation(s)
- Yuao Sun
- State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Yao Wang
- State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Keyang Chen
- Yuanpei College, Peking University, Beijing 100871, China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- National Biomedical Imaging Center, School of Future Technology, Peking University, Beijing 100871, China
| | - Sheng Wang
- School of Biopharmacy, China Pharmaceutical University, Nanjing 211198, China
- Changzhou High-Tech Research Institute of Nanjing University, Changzhou 213164, China
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7
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Yadala R, Ratnikava M, Lermontova I. Bimolecular Fluorescence Complementation to Test for Protein-Protein Interactions and to Uncover Regulatory Mechanisms During Gametogenesis. Methods Mol Biol 2022; 2484:107-120. [PMID: 35461448 DOI: 10.1007/978-1-0716-2253-7_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Bimolecular fluorescence complementation (BiFC) assay is one of the sensitive techniques that allows to investigate direct protein-protein interactions (PPI) in vivo and visualize the subcellular localization of interacting proteins. It is based on splitting of a fluorescent protein into two nonfluorescent parts accordingly fused to two putative interacting partners. If interaction between studied proteins is possible, nonfluorescent parts come to close proximity resulting in reconstitution of the functional fluorescent protein and giving fluorescence under certain wavelength. BiFC analysis implies transient or stable expression of the proteins of interest and can be used as a method to test or validate the direct PPI in various biological pathways, including the regulation of gametogenesis, which is the main focus of this book. In our protocol we give detailed information for beginners about three main steps of BiFC analysis of centromeric protein interactions. These steps include (1) generation of appropriate expression clones with the help of Gateway cloning technology, (2) infiltration of Nicotiana benthamiana plants by Agrobacteria containing generated constructs, and (3) microscopic analysis of plants under fluorescence microscope. Also, we discuss appropriate negative controls that can be used for evaluation as well as recommendable vector systems, possible artifacts and measures to avoid artifactual interactions for BiFC assay.
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Affiliation(s)
- Ramakrishna Yadala
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Maryia Ratnikava
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Inna Lermontova
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany.
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8
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Valli J, Garcia-Burgos A, Rooney LM, Vale de Melo E Oliveira B, Duncan RR, Rickman C. Seeing beyond the limit: A guide to choosing the right super-resolution microscopy technique. J Biol Chem 2021; 297:100791. [PMID: 34015334 PMCID: PMC8246591 DOI: 10.1016/j.jbc.2021.100791] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/14/2021] [Accepted: 05/14/2021] [Indexed: 02/06/2023] Open
Abstract
Super-resolution microscopy has become an increasingly popular and robust tool across the life sciences to study minute cellular structures and processes. However, with the increasing number of available super-resolution techniques has come an increased complexity and burden of choice in planning imaging experiments. Choosing the right super-resolution technique to answer a given biological question is vital for understanding and interpreting biological relevance. This is an often-neglected and complex task that should take into account well-defined criteria (e.g., sample type, structure size, imaging requirements). Trade-offs in different imaging capabilities are inevitable; thus, many researchers still find it challenging to select the most suitable technique that will best answer their biological question. This review aims to provide an overview and clarify the concepts underlying the most commonly available super-resolution techniques as well as guide researchers through all aspects that should be considered before opting for a given technique.
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Affiliation(s)
- Jessica Valli
- Edinburgh Super Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom.
| | - Adrian Garcia-Burgos
- Edinburgh Super Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Liam M Rooney
- Edinburgh Super Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Beatriz Vale de Melo E Oliveira
- Edinburgh Super Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Rory R Duncan
- Edinburgh Super Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Colin Rickman
- Edinburgh Super Resolution Imaging Consortium (ESRIC), Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom.
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9
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Zhou X, Mehta S, Zhang J. Genetically Encodable Fluorescent and Bioluminescent Biosensors Light Up Signaling Networks. Trends Biochem Sci 2020; 45:889-905. [PMID: 32660810 PMCID: PMC7502535 DOI: 10.1016/j.tibs.2020.06.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 05/25/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022]
Abstract
Cell signaling networks are intricately regulated in time and space to determine the responses and fates of cells to different cues. Genetically encodable fluorescent and bioluminescent biosensors enable the direct visualization of these spatiotemporal signaling dynamics within the native biological context, and have therefore become powerful molecular tools whose unique benefits are being used to address challenging biological questions. We first review the basis of biosensor design and remark on recent technologies that are accelerating biosensor development. We then discuss a few of the latest advances in the development and application of genetically encodable fluorescent and bioluminescent biosensors that have led to scientific or technological breakthroughs.
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Affiliation(s)
- Xin Zhou
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.
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10
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Yang G, Liu Z, Zhang R, Tian X, Chen J, Han G, Liu B, Han X, Fu Y, Hu Z, Zhang Z. A Multi‐responsive Fluorescent Probe Reveals Mitochondrial Nucleoprotein Dynamics with Reactive Oxygen Species Regulation through Super‐resolution Imaging. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005959] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Guanqing Yang
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China
| | - Zhengjie Liu
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China
| | - Ruilong Zhang
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China
- Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University) Ministry of Education Hefei Anhui 230601 China
| | - Xiaohe Tian
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China
| | - Juan Chen
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China
| | - Guangmei Han
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China
| | - Bianhua Liu
- Institute of Intelligent Machines Chinese Academy of Sciences Hefei Anhui 230031 China
| | - Xinya Han
- School of Chemistry and Chemical Engineering Anhui University of Technology Ma'anshan Anhui 243032 China
| | - Yao Fu
- Department of Chemistry University of Science and Technology of China Hefei Anhui 230026 China
| | - Zhangjun Hu
- Department of Physics, Chemistry and Biology Linköping University Linköping 58183 Sweden
| | - Zhongping Zhang
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 China
- Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University) Ministry of Education Hefei Anhui 230601 China
- Institute of Intelligent Machines Chinese Academy of Sciences Hefei Anhui 230031 China
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11
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Yang G, Liu Z, Zhang R, Tian X, Chen J, Han G, Liu B, Han X, Fu Y, Hu Z, Zhang Z. A Multi-responsive Fluorescent Probe Reveals Mitochondrial Nucleoprotein Dynamics with Reactive Oxygen Species Regulation through Super-resolution Imaging. Angew Chem Int Ed Engl 2020; 59:16154-16160. [PMID: 32573047 DOI: 10.1002/anie.202005959] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/11/2020] [Indexed: 11/06/2022]
Abstract
Understanding the biomolecular interactions in a specific organelle has been a long-standing challenge because it requires super-resolution imaging to resolve the spatial locations and dynamic interactions of multiple biomacromolecules. Two key difficulties are the scarcity of suitable probes for super-resolution nanoscopy and the complications that arise from the use of multiple probes. Herein, we report a quinolinium derivative probe that is selectively enriched in mitochondria and switches on in three different fluorescence modes in response to hydrogen peroxide (H2 O2 ), proteins, and nucleic acids, enabling the visualization of mitochondrial nucleoprotein dynamics. STED nanoscopy reveals that the proteins localize at mitochondrial cristae and largely fuse with nucleic acids to form nucleoproteins, whereas increasing H2 O2 level leads to disassociation of nucleic acid-protein complexes.
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Affiliation(s)
- Guanqing Yang
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China
| | - Zhengjie Liu
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China
| | - Ruilong Zhang
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China.,Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University), Ministry of Education, Hefei, Anhui, 230601, China
| | - Xiaohe Tian
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China
| | - Juan Chen
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China
| | - Guangmei Han
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China
| | - Bianhua Liu
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui, 230031, China
| | - Xinya Han
- School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma'anshan, Anhui, 243032, China
| | - Yao Fu
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Zhangjun Hu
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, 58183, Sweden
| | - Zhongping Zhang
- School of Chemistry and Chemical Engineering and Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, China.,Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University), Ministry of Education, Hefei, Anhui, 230601, China.,Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui, 230031, China
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12
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Fluorescent Protein-Based Indicators for Functional Super-Resolution Imaging of Biomolecular Activities in Living Cells. Int J Mol Sci 2019; 20:ijms20225784. [PMID: 31744242 PMCID: PMC6887983 DOI: 10.3390/ijms20225784] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/15/2019] [Accepted: 11/15/2019] [Indexed: 11/16/2022] Open
Abstract
Super-resolution light microscopy (SRM) offers a unique opportunity for diffraction-unlimited imaging of biomolecular activities in living cells. To realize such potential, genetically encoded indicators were developed recently from fluorescent proteins (FPs) that exhibit phototransformation behaviors including photoactivation, photoconversion, and photoswitching, etc. Super-resolution observations of biomolecule interactions and biochemical activities have been demonstrated by exploiting the principles of bimolecular fluorescence complementation (BiFC), points accumulation for imaging nanoscale topography (PAINT), and fluorescence fluctuation increase by contact (FLINC), etc. To improve functional nanoscopy with the technology of genetically encoded indicators, it is essential to fully decipher the photo-induced chemistry of FPs and opt for innovative indicator designs that utilize not only fluorescence intensity but also multi-parametric readouts such as phototransformation kinetics. In parallel, technical improvements to both the microscopy optics and image analysis pipeline are promising avenues to increase the sensitivity and versatility of functional SRM.
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13
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Optimizing the fluorescent protein toolbox and its use. Curr Opin Biotechnol 2019; 58:183-191. [DOI: 10.1016/j.copbio.2019.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/24/2019] [Indexed: 01/07/2023]
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14
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15
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Abstract
Many proteins can be split into fragments that spontaneously reassemble, without covalent linkage, into a functional protein. For split green fluorescent proteins (GFPs), fragment reassembly leads to a fluorescent readout, which has been widely used to investigate protein-protein interactions. We review the scope and limitations of this approach as well as other diverse applications of split GFPs as versatile sensors, molecular glues, optogenetic tools, and platforms for photophysical studies.
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Affiliation(s)
- Matthew G Romei
- Department of Chemistry, Stanford University, Stanford, California 94305, USA; ,
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305, USA; ,
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16
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Wang S, Shuai Y, Sun C, Xue B, Hou Y, Su X, Sun Y. Lighting Up Live Cells with Smart Genetically Encoded Fluorescence Probes from GMars Family. ACS Sens 2018; 3:2269-2277. [PMID: 30346738 DOI: 10.1021/acssensors.8b00449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As a special kind of delicate light-controllable genetically encoded optical device, reversibly photoswitchable fluorescent proteins (RSFPs) have been widely applied in many fields, especially various kinds of advanced nanoscopy approaches in recent years. However, there are still necessities for exploring novel RSFPs with specific biochemical or photophysical properties not only for bioimaging or biosensing applications but also for fluorescent protein (FP) mechanisms study and further knowledge-based molecular sensors or optical actuators' rational design and evolution. Besides previously reported GMars-Q and GMars-T variants, herein, we reported the development and applications of other RSFPs from GMars family, especially some featured RSFPs with desired optical properties. In the current work, in vitro FP purification, spectra measurements, and live-cell RESOLFT nanoscopy approaches were applied to characterize the basic properties and test the imaging performances of the selected RSFPs. As demonstrated, GMars variants such as GMars-A, GMars-G, or remarkable photofatigue-resistant GMars-L were found with beneficial properties to be capable of parallelized RESOLFT nanoscopy in living cells, while other featured GMars variants such as dark GMars-P may be a good candidate for further biosensor or actuator design and applications.
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Affiliation(s)
- Sheng Wang
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China
| | - Yao Shuai
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China
| | - Chaoying Sun
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China
| | - Boxin Xue
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China
| | - Yingping Hou
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China
| | - Xiaodong Su
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- State Key Laboratory of Protein and Plant Gene Research, Peking University, Beijing 100871, China
| | - Yujie Sun
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
- State Key Laboratory of Membrane Biology, Peking University, Beijing 100871, China
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17
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De Keersmaecker H, Camacho R, Rantasa DM, Fron E, Uji-I H, Mizuno H, Rocha S. Mapping Transient Protein Interactions at the Nanoscale in Living Mammalian Cells. ACS NANO 2018; 12:9842-9854. [PMID: 30192513 DOI: 10.1021/acsnano.8b01227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Protein-protein interactions (PPIs) form the basis of cellular processes, regulating cell behavior and fate. PPIs can be extremely transient in nature, which hinders their detection. In addition, traditional biochemical methods provided limited information on the spatial distribution and temporal dynamics of PPIs that is crucial for their regulation in the crowded cellular environment. Given the pivotal role of membrane micro- and nanodomains in the regulation of PPIs at the plasma membrane, the development of methods to visualize PPIs with a high spatial resolution is imperative. Here, we present a super-resolution fluorescence microscopy technique that can detect and map short-lived transient protein-protein interactions on a nanometer scale in the cellular environment. This imaging method is based on single-molecule fluorescence microscopy and exploits the effect of the difference in the mobility between cytosolic and membrane-bound proteins in the recorded fluorescence signals. After the development of the proof of concept using a model system based on membrane-bound modular protein domains and fluorescently labeled peptides, we applied this imaging approach to investigate the interactions of cytosolic proteins involved in the epidermal growth factor signaling pathway (namely, Grb2, c-Raf, and PLCγ1). The detected clusters of Grb2 and c-Raf were correlated with the distribution of the receptor at the plasma membrane. Additionally, the interactions of wild type PLCγ1 were compared with those detected with truncated mutants, which provided important information regarding the role played by specific domains in the interaction with the membrane. The results presented here demonstrate the potential of this technique to unravel the role of membrane heterogeneity in the spatiotemporal regulation of cell signaling.
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Affiliation(s)
| | | | | | | | - Hiroshi Uji-I
- Research Institute for Electronic Science , Hokkaido University , N20W10 Kita Ward, Sapporo 001-0020 , Japan
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18
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Wang S, Ding M, Xue B, Hou Y, Sun Y. Spying on protein interactions in living cells with reconstituted scarlet light. Analyst 2018; 143:5161-5169. [PMID: 30255175 DOI: 10.1039/c8an01223g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The BiFC (bimolecular fluorescence complementation) assay and BiFC combined with FRET (fluorescence resonance energy transfer) technique have become important tools for molecular interaction studies in live cells. However, the real detection and cellular imaging performances of most existing red fluorescent protein-derived BiFC assays still suffer from relatively low ensemble brightness, high cytotoxicity, the red fluorescent proteins being prone-to-aggregation or severe residual dimerization, inefficient complementation and slow maturation at 37 °C physiological temperature in live mammalian cells. We developed a BiFC assay based on a recently evolved truly monomeric red fluorescent protein (FP) mScarlet-I with excellent cellular performances such as low cytotoxicity, fast and efficient chromophore maturation and the highest in-cell brightness among all previously reported monomeric red fluorescent proteins. In this work, a classic β-Fos/β-Jun constitutive heterodimerization model and a rapamycin-inducible FRB/FKBP interaction system were used to establish and test the performance of the mScarlet-I-based BiFC assay in live mammalian cells. Furthermore, simply by adopting the large-Stokes-shift fluorescent protein mAmetrine as the donor, β-Jun-β-Fos-NFAT1 ternary protein complex formation could be readily and efficiently detected and visualized with minimal spectral cross-talk in live HeLa cells by combining live-cell sensitized-emission FRET measurement with the mScarlet-I-based BiFC assay. The currently established BiFC assay in this work was also shown to be able to detect and visualize various protein-protein interactions (PPIs) at different subcellular compartments with high specificity and sensitivity at 37 °C physiological temperature in live mammalian cells.
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Affiliation(s)
- Sheng Wang
- State Key Laboratory of Membrane Biology, Biomedical pioneering innovation center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China.
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19
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Altomare L, Bonetti L, Campiglio CE, De Nardo L, Draghi L, Tana F, Farè S. Biopolymer-based strategies in the design of smart medical devices and artificial organs. Int J Artif Organs 2018; 41:337-359. [PMID: 29614899 PMCID: PMC6159845 DOI: 10.1177/0391398818765323] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/26/2018] [Indexed: 12/31/2022]
Abstract
Advances in regenerative medicine and in modern biomedical therapies are fast evolving and set goals causing an upheaval in the field of materials science. This review discusses recent developments involving the use of biopolymers as smart materials, in terms of material properties and stimulus-responsive behavior, in the presence of environmental physico-chemical changes. An overview on the transformations that can be triggered in natural-based polymeric systems (sol-gel transition, polymer relaxation, cross-linking, and swelling) is presented, with specific focus on the benefits these materials can provide in biomedical applications.
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Affiliation(s)
- Lina Altomare
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milano, Italy
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Firenze, Italy
| | - Lorenzo Bonetti
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milano, Italy
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Firenze, Italy
| | - Chiara E Campiglio
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milano, Italy
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Firenze, Italy
| | - Luigi De Nardo
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milano, Italy
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Firenze, Italy
| | - Lorenza Draghi
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milano, Italy
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Firenze, Italy
| | - Francesca Tana
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milano, Italy
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Firenze, Italy
| | - Silvia Farè
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milano, Italy
- National Interuniversity Consortium of Materials Science and Technology (INSTM), Firenze, Italy
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20
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Wang S, Ding M, Xue B, Hou Y, Sun Y. Live Cell Visualization of Multiple Protein-Protein Interactions with BiFC Rainbow. ACS Chem Biol 2018; 13:1180-1188. [PMID: 29283249 DOI: 10.1021/acschembio.7b00931] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
As one of the most powerful tools to visualize PPIs in living cells, bimolecular fluorescence complementation (BiFC) has gained great advancement during recent years, including deep tissue imaging with far-red or near-infrared fluorescent proteins or super-resolution imaging with photochromic fluorescent proteins. However, little progress has been made toward simultaneous detection and visualization of multiple PPIs in the same cell, mainly due to the spectral crosstalk. In this report, we developed novel BiFC assays based on large-Stokes-shift fluorescent proteins (LSS-FPs) to detect and visualize multiple PPIs in living cells. With the large excitation/emission spectral separation, LSS-FPs can be imaged together with normal Stokes shift fluorescent proteins to realize multicolor BiFC imaging using a simple illumination scheme. We also further demonstrated BiFC rainbow combining newly developed BiFC assays with previously established mCerulean/mVenus-based BiFC assays to achieve detection and visualization of four PPI pairs in the same cell. Additionally, we prove that with the complete spectral separation of mT-Sapphire and CyOFP1, LSS-FP-based BiFC assays can be readily combined with intensity-based FRET measurement to detect ternary protein complex formation with minimal spectral crosstalk. Thus, our newly developed LSS-FP-based BiFC assays not only expand the fluorescent protein toolbox available for BiFC but also facilitate the detection and visualization of multiple protein complex interactions in living cells.
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Affiliation(s)
- Sheng Wang
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Miao Ding
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Boxin Xue
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Yingping Hou
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
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21
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Wang S, Chen X, Chang L, Ding M, Xue R, Duan H, Sun Y. GMars-T Enabling Multimodal Subdiffraction Structural and Functional Fluorescence Imaging in Live Cells. Anal Chem 2018; 90:6626-6634. [PMID: 29722976 DOI: 10.1021/acs.analchem.8b00418] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Fluorescent probes with multimodal and multilevel imaging capabilities are highly valuable as imaging with such probes not only can obtain new layers of information but also enable cross-validation of results under different experimental conditions. In recent years, the development of genetically encoded reversibly photoswitchable fluorescent proteins (RSFPs) has greatly promoted the application of various kinds of live-cell nanoscopy approaches, including reversible saturable optical fluorescence transitions (RESOLFT) and stochastic optical fluctuation imaging (SOFI). However, these two classes of live-cell nanoscopy approaches require different optical characteristics of specific RSFPs. In this work, we developed GMars-T, a monomeric bright green RSFP which can satisfy both RESOLFT and photochromic SOFI (pcSOFI) imaging in live cells. We further generated biosensor based on bimolecular fluorescence complementation (BiFC) of GMars-T which offers high specificity and sensitivity in detecting and visualizing various protein-protein interactions (PPIs) in different subcellular compartments under physiological conditions (e.g., 37 °C) in live mammalian cells. Thus, the newly developed GMars-T can serve as both structural imaging probe with multimodal super-resolution imaging capability and functional imaging probe for reporting PPIs with high specificity and sensitivity based on its derived biosensor.
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Affiliation(s)
- Sheng Wang
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences , Peking University , Beijing 100871 , China
| | - Xuanze Chen
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences , Peking University , Beijing 100871 , China.,Department of Biomedical Engineering, College of Engineering , Peking University , Beijing 100871 , China.,Cowin Venture Shanghai 200040 , China
| | - Lei Chang
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences , Peking University , Beijing 100871 , China
| | - Miao Ding
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences , Peking University , Beijing 100871 , China
| | - Ruiying Xue
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences , Peking University , Beijing 100871 , China
| | - Haifeng Duan
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences , Peking University , Beijing 100871 , China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences , Peking University , Beijing 100871 , China
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22
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Dlasková A, Engstová H, Špaček T, Kahancová A, Pavluch V, Smolková K, Špačková J, Bartoš M, Hlavatá LP, Ježek P. 3D super-resolution microscopy reflects mitochondrial cristae alternations and mtDNA nucleoid size and distribution. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:829-844. [PMID: 29727614 DOI: 10.1016/j.bbabio.2018.04.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/10/2018] [Accepted: 04/24/2018] [Indexed: 12/13/2022]
Abstract
3D super-resolution microscopy based on the direct stochastic optical reconstruction microscopy (dSTORM) with primary Alexa-Fluor-647-conjugated antibodies is a powerful method for accessing changes of objects that could be normally resolved only by electron microscopy. Despite the fact that mitochondrial cristae yet to become resolved, we have indicated changes in cristae width and/or morphology by dSTORM of ATP-synthase F1 subunit α (F1α). Obtained 3D images were analyzed with the help of Ripley's K-function modeling spatial patterns or transferring them into distance distribution function. Resulting histograms of distances frequency distribution provide most frequent distances (MFD) between the localized single antibody molecules. In fasting state of model pancreatic β-cells, INS-1E, MFD between F1α were ~80 nm at 0 and 3 mM glucose, whereas decreased to 61 nm and 57 nm upon glucose-stimulated insulin secretion (GSIS) at 11 mM and 20 mM glucose, respectively. Shorter F1α interdistances reflected cristae width decrease upon GSIS, since such repositioning of F1α correlated to average 20 nm and 15 nm cristae width at 0 and 3 mM glucose, and 9 nm or 8 nm after higher glucose simulating GSIS (11, 20 mM glucose, respectively). Also, submitochondrial entities such as nucleoids of mtDNA were resolved e.g. after bromo-deoxyuridine (BrDU) pretreatment using anti-BrDU dSTORM. MFD in distances distribution histograms reflected an average nucleoid diameter (<100 nm) and average distances between nucleoids (~1000 nm). Double channel PALM/dSTORM with Eos-lactamase-β plus anti-TFAM dSTORM confirmed the latter average inter-nucleoid distance. In conclusion, 3D single molecule (dSTORM) microscopy is a reasonable tool for studying mitochondrion.
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Affiliation(s)
- Andrea Dlasková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Engstová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Špaček
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Anežka Kahancová
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vojtěch Pavluch
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Katarína Smolková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jitka Špačková
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Bartoš
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic; Alef Ltd, Prague, Czech Republic
| | - Lydie Plecitá Hlavatá
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Ježek
- Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
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23
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Roebroek T, Duwé S, Vandenberg W, Dedecker P. Reduced Fluorescent Protein Switching Fatigue by Binding-Induced Emissive State Stabilization. Int J Mol Sci 2017; 18:ijms18092015. [PMID: 28930199 PMCID: PMC5618663 DOI: 10.3390/ijms18092015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/12/2023] Open
Abstract
Reversibly switchable fluorescent proteins (RSFPs) enable advanced fluorescence imaging, though the performance of this imaging crucially depends on the properties of the labels. We report on the use of an existing small binding peptide, named Enhancer, to modulate the spectroscopic properties of the recently developed rsGreen series of RSFPs. Fusion constructs of Enhancer with rsGreen1 and rsGreenF revealed an increased molecular brightness and pH stability, although expression in living E. coli or HeLa cells resulted in a decrease of the overall emission. Surprisingly, Enhancer binding also increased off-switching speed and resistance to switching fatigue. Further investigation suggested that the RSFPs can interconvert between fast- and slow-switching emissive states, with the overall protein population gradually converting to the slow-switching state through irradiation. The Enhancer modulates the spectroscopic properties of both states, but also preferentially stabilizes the fast-switching state, supporting the increased fatigue resistance. This work demonstrates how the photo-physical properties of RSFPs can be influenced by their binding to other small proteins, which opens up new horizons for applications that may require such modulation. Furthermore, we provide new insights into the photoswitching kinetics that should be of general consideration when developing new RSFPs with improved or different photochromic properties.
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Affiliation(s)
- Thijs Roebroek
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Sam Duwé
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Wim Vandenberg
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Peter Dedecker
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
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