1
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Jiao M, Shi X, Han Y, Xu R, Zhao S, Jia P, Zheng X, Li X, Xiao C. The screened compounds from Ligustri Lucidi Fructus using the immobilized calcium sensing receptor column exhibit osteogenic activity in vitro. J Pharm Biomed Anal 2024; 245:116192. [PMID: 38703747 DOI: 10.1016/j.jpba.2024.116192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/18/2024] [Accepted: 04/28/2024] [Indexed: 05/06/2024]
Abstract
Calcium sensing receptor (CaSR) has become the novel target of treating osteoporosis with herbal medicine Ligustri Lucidi Fructus (LLF), however, the bioactive compounds responsible for anti-osteoporosis are hard to clarify due to the complexity and diversity of chemical constituents in it. Herein, the immobilized CaSR column was packed with stationary phase materials, which were derived from integrating CLIP-tagged CaSR directly out of crude cell lysates onto the surface of silica gels (5.83 mg/g) in a site-specific covalent manner. The column had a great specificity of recognizing agonists and kept a good stability for at least 3 weeks. The two compounds from LLF extract were screened and identified as olenuezhenoside and ligustroflavone using the immobilized CaSR column in conjunction with mass spectrometry. Molecular docking predicted that both compounds were bound in venus flytrap (VFT) domain of CaSR by the formation of hydrogen bonds. Cellular results showed that both compounds exhibited the distinct osteogenic activity by enhancing the proliferation, differentiation and mineralization of osteoblastic cells. Our study demonstrated that, the immobilized protein column enables to screen the bioactive compounds rapidly from herbal extract, and the newly discovered natural product ligands towards CaSR, including olenuezhenoside and ligustroflavone, will be the candidates for the treatment of osteoporosis.
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Affiliation(s)
- Meizhi Jiao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Xiangang Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Yaokun Han
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Ru Xu
- Xi'an International University, Xi'an 710077, PR China
| | - Shoucheng Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Pu Jia
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Xiaohui Zheng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Xia Li
- Shaanxi Institute for Food and Drug Control, Xi'an 710065, PR China
| | - Chaoni Xiao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an 710069, PR China.
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2
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Suri A, Hu KKY, Younas T, Dumsday G, Haritos VS. Functionalizing Yeast Lipid Droplets as Versatile Biomaterials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2308463. [PMID: 38566530 DOI: 10.1002/smll.202308463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 01/02/2024] [Indexed: 04/04/2024]
Abstract
Lipid droplets (LD) are dynamic cellular organelles of ≈1 µm diameter in yeast where a neutral lipid core is surrounded by a phospholipid monolayer and attendant proteins. Beyond the storage of lipids, opportunities for LD engineering remain underdeveloped but they show excellent potential as new biomaterials. In this research, LD from yeast Saccharomyces cerevisiae is engineered to display mCherry fluorescent protein, Halotag ligand binding protein, plasma membrane binding v-SNARE protein, and carbonic anhydrase enzyme via linkage to oleosin, an LD anchoring protein. Each protein-oleosin fusion is coded via a single gene construct. The expressed fusion proteins are specifically displayed on LD and their functions can be assessed within cells by fluorescence confocal microscopy, TEM, and as isolated materials via AFM, flow cytometry, spectrophotometry, and by enzyme activity assay. LD isolated from the cell are shown to be robust and stabilize proteins anchored into them. These engineered LD function as reporters, bind specific ligands, guide LD and their attendant proteins into union with the plasma membrane, and catalyze reactions. Here, engineered LD functions are extended well beyond traditional lipid storage toward new material applications aided by a versatile oleosin platform anchored into LD and displaying linked proteins.
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Affiliation(s)
- Ankita Suri
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
- CSIRO Black Mountain, 2-40 Clunies Ross Street, Acton, ACT, 2601, Australia
| | - Kevin K Y Hu
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
| | - Tayyaba Younas
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
| | - Geoff Dumsday
- CSIRO Clayton, Research Way, Clayton, Victoria, 3168, Australia
| | - Victoria S Haritos
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
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3
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Devos J, Van Dijck P, Van Genechten W. A multi-colour fluorogenic tag and its application in Candida albicans. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001451. [PMID: 38535895 PMCID: PMC10995450 DOI: 10.1099/mic.0.001451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 03/13/2024] [Indexed: 04/07/2024]
Abstract
Fluorescent proteins (FPs) have always been a crucial part of molecular research in life sciences, including the research into the human fungal pathogen Candida albicans, but have obvious shortcomings such as their relatively large size and long maturation time. However, the next generation of FPs overcome these issues and rely on the binding of a fluorogen for the protein to become fluorescently active. This generation of FPs includes the improved version of Fluorescence activating and Absorption Shifting Tag (iFAST). The binding between the fluorogen and the iFAST protein is reversible, thus resulting in reversible fluorescence. The fluorogens of iFAST are analogues of 4-hydroxylbenzylidene-rhodanine (HBR). These HBR analogues differ in spectral properties depending on functional group substitutions, which gives the iFAST system flexibility in terms of absorbance and emission maxima. In this work we describe and illustrate the application of iFAST as a protein tag and its reversible multi-colour characteristics in C. albicans.
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Affiliation(s)
- Jonas Devos
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3001 Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3001 Leuven, Belgium
| | - Wouter Van Genechten
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3001 Leuven, Belgium
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4
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Grimm J, Tkachuk AN, Patel R, Hennigan ST, Gutu A, Dong P, Gandin V, Osowski AM, Holland KL, Liu ZJ, Brown TA, Lavis LD. Optimized Red-Absorbing Dyes for Imaging and Sensing. J Am Chem Soc 2023; 145:23000-23013. [PMID: 37842926 PMCID: PMC10603817 DOI: 10.1021/jacs.3c05273] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Indexed: 10/17/2023]
Abstract
Rhodamine dyes are excellent scaffolds for developing a broad range of fluorescent probes. A key property of rhodamines is their equilibrium between a colorless lactone and fluorescent zwitterion. Tuning the lactone-zwitterion equilibrium constant (KL-Z) can optimize dye properties for specific biological applications. Here, we use known and novel organic chemistry to prepare a comprehensive collection of rhodamine dyes to elucidate the structure-activity relationships that govern KL-Z. We discovered that the auxochrome substituent strongly affects the lactone-zwitterion equilibrium, providing a roadmap for the rational design of improved rhodamine dyes. Electron-donating auxochromes, such as julolidine, work in tandem with fluorinated pendant phenyl rings to yield bright, red-shifted fluorophores for live-cell single-particle tracking (SPT) and multicolor imaging. The N-aryl auxochrome combined with fluorination yields red-shifted Förster resonance energy transfer (FRET) quencher dyes useful for creating a new semisynthetic indicator to sense cAMP using fluorescence lifetime imaging microscopy (FLIM). Together, this work expands the synthetic methods available for rhodamine synthesis, generates new reagents for advanced fluorescence imaging experiments, and describes structure-activity relationships that will guide the design of future probes.
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Affiliation(s)
- Jonathan
B. Grimm
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Ariana N. Tkachuk
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Ronak Patel
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - S. Thomas Hennigan
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Alina Gutu
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Peng Dong
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Valentina Gandin
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Anastasia M. Osowski
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Katie L. Holland
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Zhe J. Liu
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Timothy A. Brown
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Luke D. Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia 20147, United States
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5
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Schirripa Spagnolo C, Moscardini A, Amodeo R, Beltram F, Luin S. Quantitative determination of fluorescence labeling implemented in cell cultures. BMC Biol 2023; 21:190. [PMID: 37697318 PMCID: PMC10496409 DOI: 10.1186/s12915-023-01685-0] [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: 11/29/2022] [Accepted: 08/18/2023] [Indexed: 09/13/2023] Open
Abstract
BACKGROUND Labeling efficiency is a crucial parameter in fluorescence applications, especially when studying biomolecular interactions. Current approaches for estimating the yield of fluorescent labeling have critical drawbacks that usually lead them to be inaccurate or not quantitative. RESULTS We present a method to quantify fluorescent-labeling efficiency that addresses the critical issues marring existing approaches. The method operates in the same conditions of the target experiments by exploiting a ratiometric evaluation with two fluorophores used in sequential reactions. We show the ability of the protocol to extract reliable quantification for different fluorescent probes, reagents concentrations, and reaction timing and to optimize labeling performance. As paradigm, we consider the labeling of the membrane-receptor TrkA through 4'-phosphopantetheinyl transferase Sfp in living cells, visualizing the results by TIRF microscopy. This investigation allows us to find conditions for demanding single and multi-color single-molecule studies requiring high degrees of labeling. CONCLUSIONS The developed method allows the quantitative determination and the optimization of staining efficiency in any labeling strategy based on stable reactions.
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Affiliation(s)
| | - Aldo Moscardini
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Rosy Amodeo
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
- Present address: Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072, Milan, Italy
| | - Fabio Beltram
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
- NEST Laboratory, Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Stefano Luin
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy.
- NEST Laboratory, Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127, Pisa, Italy.
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6
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de Lange EMF, Vlijm R. Super-Resolution Imaging of Peroxisomal Proteins Using STED Nanoscopy. Methods Mol Biol 2023; 2643:65-84. [PMID: 36952178 DOI: 10.1007/978-1-0716-3048-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Peroxisomes are crucial organelles that occur in almost all eukaryotes. Well known are their roles in various metabolic processes, such as hydrogen peroxide detoxification and lipid metabolism. Recent studies indicated that peroxisomes also have several non-metabolic functions, for instance, in stress response, signaling, and cellular ageing. In mammalian cells, the small size of peroxisomes (~200 nm, near the diffraction limit) hinders unveiling peroxisomal structures by conventional light microscopy. However, in the yeast Hansenula polymorpha, they can reach up to 1.5 μm in diameter, depending on the carbon source. To study the localization of peroxisomal proteins in cells in more detail, super-resolution imaging techniques such as stimulated emission depletion (STED) microscopy can be used. STED enables fast (live-cell) imaging well beyond the diffraction limit of light (30-40 nm in cells), without further data processing. Here, we present optimized protocols for the fluorescent labeling of specific peroxisomal proteins in fixed and living cells. Moreover, detailed measurement protocols for successful STED imaging of human and yeast peroxisomes (using antibodies or genetic tags labeled with dyes) are described, extended with suggestions for individual optimizations.
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Affiliation(s)
- Eline M F de Lange
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
- Molecular Biophysics, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Rifka Vlijm
- Molecular Biophysics, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands.
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7
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Chakraborty A, Krause L, Klostermeier D. Determination of rate constants for conformational changes of RNA helicases by single-molecule FRET TIRF microscopy. Methods 2022; 204:428-441. [PMID: 35304246 DOI: 10.1016/j.ymeth.2022.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 03/10/2022] [Accepted: 03/13/2022] [Indexed: 12/18/2022] Open
Abstract
RNA helicases couple nucleotide-driven conformational changes to the unwinding of RNA duplexes. Interaction partners can regulate helicase activity by altering the rate constants of these conformational changes. Single-molecule FRET experiments on donor/acceptor-labeled, immobilized molecules are ideally suited to monitor conformational changes in real time and to extract rate constants for these processes. This article provides guidance on how to design, perform, and analyze single-molecule FRET experiments by TIRF microscopy. It covers the theoretical background of FRET and single-molecule TIRF microscopy, the considerations to prepare proteins of interest for donor/acceptor labeling and surface immobilization, and the principles and procedures of data analysis, including image analysis and the determination of FRET time traces, the extraction of rate constants from FRET time traces, and the general conclusions that can be drawn from these data. A case study, using the DEAD-box protein eIF4A as an example, highlights how single-molecule FRET studies have been instrumental in understanding the role of conformational changes for duplex unwinding and for the regulation of helicase activities. Selected examples illustrate which conclusions can be drawn from the kinetic data obtained, highlight possible pitfalls in data analysis and interpretation, and outline how kinetic models can be related to functionally relevant states.
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Affiliation(s)
| | - Linda Krause
- University of Muenster, Institute for Physical Chemistry, Muenster, Germany
| | - Dagmar Klostermeier
- University of Muenster, Institute for Physical Chemistry, Muenster, Germany.
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8
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Oliveira Paiva AM, Friggen AH, Douwes R, Wittekoek B, Smits WK. Practical observations on the use of fluorescent reporter systems in Clostridioides difficile. Antonie van Leeuwenhoek 2022; 115:297-323. [PMID: 35039954 DOI: 10.1007/s10482-021-01691-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/19/2021] [Indexed: 12/18/2022]
Abstract
Fluorescence microscopy is a valuable tool to study a broad variety of bacterial cell components and dynamics thereof. For Clostridioides difficile, the fluorescent proteins CFPopt, mCherryOpt and phiLOV2.1, and the self-labelling tags SNAPCd and HaloTag, hereafter collectively referred as fluorescent systems, have been described to explore different cellular pathways. In this study, we sought to characterize previously used fluorescent systems in C. difficile cells. We performed single cell analyses using fluorescence microscopy of exponentially growing C. difficile cells harbouring different fluorescent systems, either expressing these separately in the cytosol or fused to the C-terminus of HupA, under defined conditions. We show that the intrinsic fluorescence of C. difficile cells increases during growth, independent of sigB or spo0A. However, when C. difficile cells are exposed to environmental oxygen autofluorescence is enhanced. Cytosolic overexpression of the different fluorescent systems alone, using the same expression signals, showed heterogeneous expression of the fluorescent systems. High levels of mCherryOpt were toxic for C. difficile cells limiting the applicability of this fluorophore as a transcriptional reporter. When fused to HupA, a C. difficile histone-like protein, the fluorescent systems behaved similarly and did not affect the HupA overproduction phenotype. The present study compares several commonly used fluorescent systems for application as transcriptional or translational reporters in microscopy and summarizes the limitations and key challenges for live-cell imaging of C. difficile. Due to independence of molecular oxygen and fluorescent signal, SNAPCd appears the most suitable candidate for live-cell imaging in C. difficile to date.
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Affiliation(s)
- Ana M Oliveira Paiva
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands.,Center for Microbial Cell Biology, Leiden, The Netherlands.,Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198, Gif-sur-Yvette, France
| | - Annemieke H Friggen
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands.,Center for Microbial Cell Biology, Leiden, The Netherlands
| | - Roxanne Douwes
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Bert Wittekoek
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands. .,Center for Microbial Cell Biology, Leiden, The Netherlands.
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9
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Zhang M, Seitz C, Chang G, Iqbal F, Lin H, Liu J. A guide for single-particle chromatin tracking in live cell nuclei. Cell Biol Int 2022; 46:683-700. [PMID: 35032142 PMCID: PMC9035067 DOI: 10.1002/cbin.11762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 12/29/2021] [Accepted: 01/08/2022] [Indexed: 11/09/2022]
Abstract
The emergence of labeling strategies and live cell imaging methods enables the imaging of chromatin in living cells at single digit nanometer resolution as well as milliseconds temporal resolution. These technical breakthroughs revolutionize our understanding of chromatin structure, dynamics and functions. Single molecule tracking algorithms are usually preferred to quantify the movement of these intranucleus elements to interpret the spatiotemporal evolution of the chromatin. In this review, we will first summarize the fluorescent labeling strategy of chromatin in live cells which will be followed by a sys-tematic comparison of live cell imaging instrumentation. With the proper microscope, we will discuss the image analysis pipelines to extract the biophysical properties of the chromatin. Finally, we expect to give practical suggestions to broad biologists on how to select methods and link to the model properly according to different investigation pur-poses. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mengdi Zhang
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Clayton Seitz
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Garrick Chang
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Fadil Iqbal
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Hua Lin
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Jing Liu
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA.,Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, IN, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
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10
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Analysis of the conformational space and dynamics of RNA helicases by single-molecule FRET in solution and on surfaces. Methods Enzymol 2022; 673:251-310. [DOI: 10.1016/bs.mie.2022.03.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Podh NK, Paliwal S, Dey P, Das A, Morjaria S, Mehta G. In-vivo Single-Molecule Imaging in Yeast: Applications and Challenges. J Mol Biol 2021; 433:167250. [PMID: 34537238 DOI: 10.1016/j.jmb.2021.167250] [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: 07/01/2021] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 10/20/2022]
Abstract
Single-molecule imaging has gained momentum to quantify the dynamics of biomolecules in live cells, as it provides direct real-time measurements of various cellular activities under their physiological environment. Yeast, a simple and widely used eukaryote, serves as a good model system to quantify single-molecule dynamics of various cellular processes because of its low genomic and cellular complexities, as well as its facile ability to be genetically manipulated. In the past decade, significant developments have been made regarding the intracellular labeling of biomolecules (proteins, mRNA, fatty acids), the microscopy setups to visualize single-molecules and capture their fast dynamics, and the data analysis pipelines to interpret such dynamics. In this review, we summarize the current state of knowledge for the single-molecule imaging in live yeast cells to provide a ready reference for beginners. We provide a comprehensive table to demonstrate how various labs tailored the imaging regimes and data analysis pipelines to estimate various biophysical parameters for a variety of biological processes. Lastly, we present current challenges and future directions for developing better tools and resources for single-molecule imaging in live yeast cells.
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Affiliation(s)
- Nitesh Kumar Podh
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India. https://twitter.com/@PodhNitesh
| | - Sheetal Paliwal
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India. https://twitter.com/@Sheetal62666036
| | - Partha Dey
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India. https://twitter.com/@ParthaD63416958
| | - Ayan Das
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India. https://twitter.com/@AyanDas76471821
| | - Shruti Morjaria
- Dr. Vikram Sarabhai Institute of Cell and Molecular Biology, The Maharaja Sayajirao University of Baroda, Vadodara, India. https://twitter.com/@shruti_morjaria
| | - Gunjan Mehta
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India.
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12
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Computerized fluorescence microscopy of microbial cells. World J Microbiol Biotechnol 2021; 37:189. [PMID: 34617135 DOI: 10.1007/s11274-021-03159-3] [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: 07/27/2021] [Accepted: 09/30/2021] [Indexed: 10/20/2022]
Abstract
The upgrading of fluorescence microscopy by the introduction of computer technologies has led to the creation of a new methodology, computerized fluorescence microscopy (CFM). CFM improves subjective visualization and combines it with objective quantitative analysis of the microscopic data. CFM has opened up two fundamentally new opportunities for studying microorganisms. The first is the quantitative measurement of the fluorescence parameters of the targeted fluorophores in association with certain structures of individual cells. The second is the expansion of the boundaries of visualization/resolution of intracellular components beyond the "diffraction limit" of light microscopy into the nanometer range. This enables to obtain unique information about the localization and dynamics of intracellular processes at the molecular level. The purpose of this review is to demonstrate the potential of CFM in the study of fundamental aspects of the structural and functional organization of microbial cells. The basics of computer processing and analysis of digital images are briefly described. The fluorescent molecules used in CFM with an emphasis on fluorescent proteins are characterized. The main methods of super-resolution microscopy (nanoscopy) are presented. The capabilities of various CFM methods for exploring microbial cells at the subcellular level are illustrated by the examples of various studies on yeast and bacteria.
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13
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Van Genechten W, Van Dijck P, Demuyser L. Fluorescent toys 'n' tools lighting the way in fungal research. FEMS Microbiol Rev 2021; 45:fuab013. [PMID: 33595628 PMCID: PMC8498796 DOI: 10.1093/femsre/fuab013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 02/14/2021] [Indexed: 12/13/2022] Open
Abstract
Although largely overlooked compared to bacterial infections, fungal infections pose a significant threat to the health of humans and other organisms. Many pathogenic fungi, especially Candida species, are extremely versatile and flexible in adapting to various host niches and stressful situations. This leads to high pathogenicity and increasing resistance to existing drugs. Due to the high level of conservation between fungi and mammalian cells, it is hard to find fungus-specific drug targets for novel therapy development. In this respect, it is vital to understand how these fungi function on a molecular, cellular as well as organismal level. Fluorescence imaging allows for detailed analysis of molecular mechanisms, cellular structures and interactions on different levels. In this manuscript, we provide researchers with an elaborate and contemporary overview of fluorescence techniques that can be used to study fungal pathogens. We focus on the available fluorescent labelling techniques and guide our readers through the different relevant applications of fluorescent imaging, from subcellular events to multispecies interactions and diagnostics. As well as cautioning researchers for potential challenges and obstacles, we offer hands-on tips and tricks for efficient experimentation and share our expert-view on future developments and possible improvements.
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Affiliation(s)
- Wouter Van Genechten
- VIB-KU Leuven Center for Microbiology, Kasteelpark Arenberg 31, 3001 Leuven-heverlee, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Belgium
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200g, 3001 Leuven-Heverlee, Belgium
| | - Patrick Van Dijck
- VIB-KU Leuven Center for Microbiology, Kasteelpark Arenberg 31, 3001 Leuven-heverlee, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Belgium
| | - Liesbeth Demuyser
- VIB-KU Leuven Center for Microbiology, Kasteelpark Arenberg 31, 3001 Leuven-heverlee, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Belgium
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14
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Anaerobic fluorescent reporters for cell identification, microbial cell biology and high-throughput screening of microbiota and genomic libraries. Curr Opin Biotechnol 2021; 71:151-163. [PMID: 34375813 DOI: 10.1016/j.copbio.2021.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/08/2021] [Indexed: 11/23/2022]
Abstract
The lack of real-time reporters in obligate anaerobes has limited studies in gene expression, promoter characterization, library screening, population dynamics, and cell biology in these organisms. While the use of enzymatic, colorimetric, and luminescent reporters has been reported, the need for reliable anaerobic fluorescent proteins is widely acknowledged. Recently, the fluorescent proteins HaloTag, SNAP-tag and FAST have been established as reliable reporters in Clostridium spp., thus suggesting that these reporters can be adopted widely for many obligate anaerobes. With a multitude of labeling options, these anaerobic fluorescent proteins hold a great potential for screening promoters, terminators, and RBS sites, tracking population dynamics in complex multi-species co-cultures, such as microbiomes, screening libraries, and in cell biology studies of protein localization and interactions using high-resolution microscopy.
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15
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Machado JH, Ting R, Lin JY, Rodriguez EA. A self-labeling protein based on the small ultra-red fluorescent protein, smURFP. RSC Chem Biol 2021; 2:1221-1226. [PMID: 34458834 PMCID: PMC8341759 DOI: 10.1039/d1cb00127b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 06/24/2021] [Indexed: 12/25/2022] Open
Abstract
Self-labeling proteins have revolutionized super-resolution and sensor imaging. Tags recognize a bioorthogonal substrate for covalent attachment. We show the small Ultra-Red Fluorescent Protein (smURFP) is a self-labeling protein. The substrate is fluorogenic, fluoresces when attached, and quenches fluorescent cargo. The smURFP-tag has novel properties for tool development.
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Affiliation(s)
- John-Hanson Machado
- Department of Chemistry, The George Washington University Washington DC 20052 USA
| | - Richard Ting
- Department of Radiology, Molecular Imaging Innovations Institute (MI3), Weill Cornell Medicine New York NY 10065 USA
- Antelope Surgical, Biolabs@NYULangone New York NY 10014 USA
| | - John Y Lin
- Tasmanian School of Medicine, University of Tasmania Hobart Tasmania 7000 Australia
| | - Erik A Rodriguez
- Department of Chemistry, The George Washington University Washington DC 20052 USA
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16
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Laxman P, Ansari S, Gaus K, Goyette J. The Benefits of Unnatural Amino Acid Incorporation as Protein Labels for Single Molecule Localization Microscopy. Front Chem 2021; 9:641355. [PMID: 33842432 PMCID: PMC8027105 DOI: 10.3389/fchem.2021.641355] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/26/2021] [Indexed: 01/07/2023] Open
Abstract
Single Molecule Localization Microscopy (SMLM) is an imaging method that allows for the visualization of structures smaller than the diffraction limit of light (~200 nm). This is achieved through techniques such as stochastic optical reconstruction microscopy (STORM) and photoactivated localization microscopy (PALM). A large part of obtaining ideal imaging of single molecules is the choice of the right fluorescent label. An upcoming field of protein labeling is incorporating unnatural amino acids (UAAs) with an attached fluorescent dye for precise localization and visualization of individual molecules. For this technique, fluorescent probes are conjugated to UAAs and are introduced into the protein of interest (POI) as a label. Here we contrast this labeling method with other commonly used protein-based labeling methods such as fluorescent proteins (FPs) or self-labeling tags such as Halotag, SNAP-tags, and CLIP-tags, and highlight the benefits and shortcomings of the site-specific incorporation of UAAs coupled with fluorescent dyes in SMLM.
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Affiliation(s)
| | | | | | - Jesse Goyette
- European Molecular Biology Laboratory (EMBL) Australia Node in Single Molecule Sciences, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
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17
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TALEN outperforms Cas9 in editing heterochromatin target sites. Nat Commun 2021; 12:606. [PMID: 33504770 PMCID: PMC7840734 DOI: 10.1038/s41467-020-20672-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/19/2020] [Indexed: 01/01/2023] Open
Abstract
Genome editing critically relies on selective recognition of target sites. However, despite recent progress, the underlying search mechanism of genome-editing proteins is not fully understood in the context of cellular chromatin environments. Here, we use single-molecule imaging in live cells to directly study the behavior of CRISPR/Cas9 and TALEN. Our single-molecule imaging of genome-editing proteins reveals that Cas9 is less efficient in heterochromatin than TALEN because Cas9 becomes encumbered by local searches on non-specific sites in these regions. We find up to a fivefold increase in editing efficiency for TALEN compared to Cas9 in heterochromatin regions. Overall, our results show that Cas9 and TALEN use a combination of 3-D and local searches to identify target sites, and the nanoscopic granularity of local search determines the editing outcomes of the genome-editing proteins. Taken together, our results suggest that TALEN is a more efficient gene-editing tool than Cas9 for applications in heterochromatin.
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18
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Auboiron M, Vasseur P, Tonazzini S, Fall A, Castro FR, Sučec I, El Koulali K, Urbach S, Radman-Livaja M. TrIPP-a method for tracking the inheritance patterns of proteins in living cells-reveals retention of Tup1p, Fpr4p, and Rpd3L in the mother cell. iScience 2021; 24:102075. [PMID: 33644711 PMCID: PMC7889982 DOI: 10.1016/j.isci.2021.102075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/27/2020] [Accepted: 01/15/2021] [Indexed: 01/16/2023] Open
Abstract
Inheritance of chromatin-bound proteins theoretically plays a role in the epigenetic transmission of cellular phenotypes. Protein segregation during cell division is however poorly understood. We now describe TrIPP (Tracking the Inheritance Patterns of Proteins): a live cell imaging method for tracking maternal proteins during asymmetric cell divisions of budding yeast. Our analysis of the partitioning pattern of a test set of 18 chromatin-associated proteins reveals that abundant and moderately abundant maternal proteins segregate stochastically and symmetrically between the two cells with the exception of Rxt3p, Fpr4p, and Tup1p, which are preferentially retained in the mother. Low abundance proteins also tend to be retained in the mother cell with the exception of Sir2p and the linker histone H1. Our analysis of chromatin protein behavior in single cells reveals potentially general trends such as coupled protein synthesis and decay and a correlation between protein half-lives and cell-cycle duration.
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Affiliation(s)
- Morgane Auboiron
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
| | - Pauline Vasseur
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Saphia Tonazzini
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
| | - Arame Fall
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
| | - Francesc Rubert Castro
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Iva Sučec
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Khadija El Koulali
- Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France.,Functional Proteomics Platform, IGF _ CNRS INSERM, Université de Montpellier, 141 rue de la Cardonille, 34094 Montpellier cedex 5, France
| | - Serge Urbach
- Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France.,Functional Proteomics Platform, IGF _ CNRS INSERM, Université de Montpellier, 141 rue de la Cardonille, 34094 Montpellier cedex 5, France
| | - Marta Radman-Livaja
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 route de Mende, 34293 Montpellier cedex 5, France.,Université de Montpellier, 163 rue Auguste Broussonnet, 34090 Montpellier, France
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19
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G. Keller S, Kamiya M, Urano Y. Recent Progress in Small Spirocyclic, Xanthene-Based Fluorescent Probes. Molecules 2020; 25:E5964. [PMID: 33339370 PMCID: PMC7766215 DOI: 10.3390/molecules25245964] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/14/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
The use of fluorescent probes in a multitude of applications is still an expanding field. This review covers the recent progress made in small molecular, spirocyclic xanthene-based probes containing different heteroatoms (e.g., oxygen, silicon, carbon) in position 10'. After a short introduction, we will focus on applications like the interaction of probes with enzymes and targeted labeling of organelles and proteins, detection of small molecules, as well as their use in therapeutics or diagnostics and super-resolution microscopy. Furthermore, the last part will summarize recent advances in the synthesis and understanding of their structure-behavior relationship including novel computational approaches.
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Affiliation(s)
- Sascha G. Keller
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; (S.G.K.); (M.K.)
| | - Mako Kamiya
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; (S.G.K.); (M.K.)
| | - Yasuteru Urano
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; (S.G.K.); (M.K.)
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
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20
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Ong JY, Bradley MC, Torres JZ. Phospho-regulation of mitotic spindle assembly. Cytoskeleton (Hoboken) 2020; 77:558-578. [PMID: 33280275 PMCID: PMC7898546 DOI: 10.1002/cm.21649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/08/2020] [Accepted: 12/02/2020] [Indexed: 12/23/2022]
Abstract
The assembly of the bipolar mitotic spindle requires the careful orchestration of a myriad of enzyme activities like protein posttranslational modifications. Among these, phosphorylation has arisen as the principle mode for spatially and temporally activating the proteins involved in early mitotic spindle assembly processes. Here, we review key kinases, phosphatases, and phosphorylation events that regulate critical aspects of these processes. We highlight key phosphorylation substrates that are important for ensuring the fidelity of centriole duplication, centrosome maturation, and the establishment of the bipolar spindle. We also highlight techniques used to understand kinase-substrate relationships and to study phosphorylation events. We conclude with perspectives on the field of posttranslational modifications in early mitotic spindle assembly.
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Affiliation(s)
- Joseph Y Ong
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA
| | - Michelle C Bradley
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA
| | - Jorge Z Torres
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA.,Molecular Biology Institute, University of California, Los Angeles, California, USA.,Jonsson Comprehensive Cancer Center, University of California, Los Angeles, California, USA
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21
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Biteghe FAN, Mungra N, Chalomie NET, Ndong JDLC, Engohang-Ndong J, Vignaux G, Padayachee E, Naran K, Barth S. Advances in epidermal growth factor receptor specific immunotherapy: lessons to be learned from armed antibodies. Oncotarget 2020; 11:3531-3557. [PMID: 33014289 PMCID: PMC7517958 DOI: 10.18632/oncotarget.27730] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022] Open
Abstract
The epidermal growth factor receptor (EGFR) has been recognized as an important therapeutic target in oncology. It is commonly overexpressed in a variety of solid tumors and is critically involved in cell survival, proliferation, metastasis, and angiogenesis. This multi-dimensional role of EGFR in the progression and aggressiveness of cancer, has evolved from conventional to more targeted therapeutic approaches. With the advent of hybridoma technology and phage display techniques, the first anti-EGFR monoclonal antibodies (mAbs) (Cetuximab and Panitumumab) were developed. Due to major limitations including host immune reactions and poor tumor penetration, these antibodies were modified and used as guiding mechanisms for the specific delivery of readily available chemotherapeutic agents or plants/bacterial toxins, giving rise to antibody-drug conjugates (ADCs) and immunotoxins (ITs), respectively. Continued refinement of ITs led to deimmunization strategies based on depletion of B and T-cell epitopes or substitution of non-human toxins leading to a growing repertoire of human enzymes capable of inducing cell death. Similarly, the modification of classical ADCs has resulted in the first, fully recombinant versions. In this review, we discuss significant advancements in EGFR-targeting immunoconjugates, including ITs and recombinant photoactivable ADCs, which serve as a blueprint for further developments in the evolving domain of cancer immunotherapy.
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Affiliation(s)
- Fleury Augustin Nsole Biteghe
- Department of Radiation Oncology and Biomedical Sciences, Cedars-Sinai Medical, Los Angeles, CA, USA.,These authors contributed equally to this work
| | - Neelakshi Mungra
- Medical Biotechnology & Immunotherapy Research Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,These authors contributed equally to this work
| | | | - Jean De La Croix Ndong
- Department of Orthopedic Surgery, New York University School of Medicine, New York, NY, USA
| | - Jean Engohang-Ndong
- Department of Biological Sciences, Kent State University at Tuscarawas, New Philadelphia, OH, USA
| | | | - Eden Padayachee
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Krupa Naran
- Medical Biotechnology & Immunotherapy Research Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,These authors contributed equally to this work
| | - Stefan Barth
- Medical Biotechnology & Immunotherapy Research Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,These authors contributed equally to this work
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22
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Antibody-Based Immunotherapy: Alternative Approaches for the Treatment of Metastatic Melanoma. Biomedicines 2020; 8:biomedicines8090327. [PMID: 32899183 PMCID: PMC7555584 DOI: 10.3390/biomedicines8090327] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022] Open
Abstract
Melanoma is the least common form of skin cancer and is associated with the highest mortality. Where melanoma is mostly unresponsive to conventional therapies (e.g., chemotherapy), BRAF inhibitor treatment has shown improved therapeutic outcomes. Photodynamic therapy (PDT) relies on a light-activated compound to produce death-inducing amounts of reactive oxygen species (ROS). Their capacity to selectively accumulate in tumor cells has been confirmed in melanoma treatment with some encouraging results. However, this treatment approach has not reached clinical fruition for melanoma due to major limitations associated with the development of resistance and subsequent side effects. These adverse effects might be bypassed by immunotherapy in the form of antibody–drug conjugates (ADCs) relying on the ability of monoclonal antibodies (mAbs) to target specific tumor-associated antigens (TAAs) and to be used as carriers to specifically deliver cytotoxic warheads into corresponding tumor cells. Of late, the continued refinement of ADC therapeutic efficacy has given rise to photoimmunotherapy (PIT) (a light-sensitive compound conjugated to mAbs), which by virtue of requiring light activation only exerts its toxic effect on light-irradiated cells. As such, this review aims to highlight the potential clinical benefits of various armed antibody-based immunotherapies, including PDT, as alternative approaches for the treatment of metastatic melanoma.
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23
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Štefl M, Herbst K, Rübsam M, Benda A, Knop M. Single-Color Fluorescence Lifetime Cross-Correlation Spectroscopy In Vivo. Biophys J 2020; 119:1359-1370. [PMID: 32919495 DOI: 10.1016/j.bpj.2020.06.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/29/2020] [Accepted: 06/16/2020] [Indexed: 01/18/2023] Open
Abstract
The ability to quantify protein concentrations and to measure protein interactions in vivo is key information needed for the understanding of complex processes inside cells, but the acquisition of such information from living cells is still demanding. Fluorescence-based methods like two-color fluorescence cross-correlation spectroscopy can provide this information, but measurement precision is hampered by various sources of errors caused by instrumental or optical limitations such as imperfect overlap of detection volumes or detector cross talk. Furthermore, the nature and properties of used fluorescent proteins or fluorescent dyes, such as labeling efficiency, fluorescent protein maturation, photostability, bleaching, and fluorescence brightness can have an impact. Here, we take advantage of previously published fluorescence lifetime correlation spectroscopy which relies on lifetime differences as a mean to discriminate fluorescent proteins with similar spectral properties and to use them for single-color fluorescence lifetime cross-correlation spectroscopy (sc-FLCCS). By using only one excitation and one detection wavelength, this setup avoids all sources of errors resulting from chromatic aberrations and detector cross talk. To establish sc-FLCCS, we first engineered and tested multiple green fluorescent protein (GFP)-like fluorescent proteins for their suitability. This identified a novel, to our knowledge, GFP variant termed short-lifetime monomeric GFP with the so-far shortest lifetime. Monte-Carlo simulations were employed to explore the suitability of different combinations of GFP variants. Two GFPs, Envy and short-lifetime monomeric GFP, were predicted to constitute the best performing couple for sc-FLCCS measurements. We demonstrated application of this GFP pair for measuring protein interactions between the proteasome and interacting proteins and for measuring protein interactions between three partners when combined with a red florescent protein. Together, our findings establish sc-FLCCS as a valid alternative for conventional dual-color fluorescence cross-correlation spectroscopy measurements.
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Affiliation(s)
- Martin Štefl
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Heidelberg, Germany; J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Prague, Czech Republic.
| | - Konrad Herbst
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Heidelberg, Germany
| | - Marc Rübsam
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Heidelberg, Germany
| | - Aleš Benda
- IMCF at BIOCEV, Faculty of Science, Charles University, Vestec, Czech Republic
| | - Michael Knop
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Heidelberg, Germany; Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
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24
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Frøsig MM, Costa SR, Liesche J, Østerberg JT, Hanisch S, Nintemann S, Sørensen H, Palmgren M, Pomorski TG, López-Marqués RL. Pseudohyphal growth in Saccharomyces cerevisiae involves protein kinase-regulated lipid flippases. J Cell Sci 2020; 133:jcs235994. [PMID: 32661085 DOI: 10.1242/jcs.235994] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 07/01/2020] [Indexed: 12/15/2022] Open
Abstract
Lipid flippases of the P4 ATPase family establish phospholipid asymmetry in eukaryotic cell membranes and are involved in many essential cellular processes. The yeast Saccharomyces cerevisiae contains five P4 ATPases, among which Dnf3p is poorly characterized. Here, we demonstrate that Dnf3p is a flippase that catalyzes translocation of major glycerophospholipids, including phosphatidylserine, towards the cytosolic membrane leaflet. Deletion of the genes encoding Dnf3p and the distantly related P4 ATPases Dnf1p and Dnf2p results in yeast mutants with aberrant formation of pseudohyphae, suggesting that the Dnf1p-Dnf3p proteins have partly redundant functions in the control of this specialized form of polarized growth. Furthermore, as previously demonstrated for Dnf1 and Dnf2p, the phospholipid flipping activity of Dnf3p is positively regulated by flippase kinase 1 (Fpk1p) and Fpk2p. Phylogenetic analyses demonstrate that Dnf3p belongs to a subfamily of P4 ATPases specific for fungi and are likely to represent a hallmark of fungal evolution.
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Affiliation(s)
- Merethe Mørch Frøsig
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
| | - Sara Rute Costa
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
| | - Johannes Liesche
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
| | - Jeppe Thulin Østerberg
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
| | - Susanne Hanisch
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
| | - Sebastian Nintemann
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
| | - Helle Sørensen
- Data Science Lab, Department of Mathematical Sciences, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark
| | - Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
| | - Thomas Günther Pomorski
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Rosa L López-Marqués
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK - 1871 Frederiksberg C, Denmark
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25
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A general method to optimize and functionalize red-shifted rhodamine dyes. Nat Methods 2020; 17:815-821. [PMID: 32719532 PMCID: PMC7396317 DOI: 10.1038/s41592-020-0909-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/22/2020] [Indexed: 12/29/2022]
Abstract
Expanding the palette of fluorescent dyes is vital to push the frontier of biological imaging. Although rhodamine dyes remain the premier type of small-molecule fluorophore due to their bioavailability and brightness, variants excited with far-red or near-infrared light suffer from poor performance due to their propensity to adopt a lipophilic, nonfluorescent form. We report a framework for rationalizing rhodamine behavior in biological environments and a general chemical modification for rhodamines that optimizes long-wavelength variants and enables facile functionalization with different chemical groups.
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26
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Chia HE, Zuo T, Koropatkin NM, Marsh ENG, Biteen JS. Imaging living obligate anaerobic bacteria with bilin-binding fluorescent proteins. CURRENT RESEARCH IN MICROBIAL SCIENCES 2020; 1:1-6. [PMID: 33313576 PMCID: PMC7731933 DOI: 10.1016/j.crmicr.2020.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Conventional fluorescent proteins like GFP are restricted to aerobic environments. Bilin-binding fluorescent proteins (BBFPs) enable live-cell imaging of anaerobes. We implemented BBFPs to fluorescently label prevalent gut microbiome species. The UnaG and IFP2.0 BBFPs can be used in multi-species multicolor microscopy.
Fluorescent tools such as green fluorescent protein (GFP) have been used extensively as reporters in biochemistry and microbiology, but GFP and other conventional fluorescent proteins are restricted to aerobic environments. This limitation precludes fluorescence studies of anaerobic ecologies including polymicrobial communities in the human gut microbiome and in soil microbiomes, which profoundly affect health, disease, and the environment. To address this limitation, we describe the first implementation of two bilin-binding fluorescent proteins (BBFPs), UnaG and IFP2.0, as oxygen-independent fluorescent labels for live-cell imaging in anaerobic bacteria. Expression of UnaG or IFP2.0 in the prevalent gut bacterium Bacteroides thetaiotaomicron (B. theta) results in detectable fluorescence upon the addition of the bilirubin or biliverdin ligand, even in anaerobic conditions. Furthermore, these BBFPs can be used in two-color imaging to differentiate cells expressing either UnaG or IFP2.0; UnaG and IFP2.0 can also be used to distinguish B. theta from other common gut bacterial species in mixed-culture live-cell imaging. BBFPs are promising fluorescent tools for live-cell imaging investigations of otherwise inaccessible anaerobic polymicrobial communities.
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Affiliation(s)
- Hannah E Chia
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
| | - Tiancheng Zuo
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - E Neil G Marsh
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.,Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Julie S Biteen
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA.,Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
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27
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Mori M, Fujikawa Y, Inoue H. Convenient synthesis of regioisomerically pure 5- and 6-functionalized xanthene dyes via SNAr reaction and comparison of their reactivity towards click reaction. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.131087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Veggiani G, Giabbai B, Semrau MS, Medagli B, Riccio V, Bajc G, Storici P, de Marco A. Comparative analysis of fusion tags used to functionalize recombinant antibodies. Protein Expr Purif 2020; 166:105505. [DOI: 10.1016/j.pep.2019.105505] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 09/20/2019] [Accepted: 09/25/2019] [Indexed: 02/06/2023]
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29
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Gerasimaitė R, Seikowski J, Schimpfhauser J, Kostiuk G, Gilat T, D'Este E, Schnorrenberg S, Lukinavičius G. Efflux pump insensitive rhodamine–jasplakinolide conjugates for G- and F-actin imaging in living cells. Org Biomol Chem 2020; 18:2929-2937. [DOI: 10.1039/d0ob00369g] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Fluorescent actin probes made of 6′-carbopyronines and jasplakinolide are insensitive to efflux pumps and stain F- and G-actin efficiently in living cells, allowing high quality 2D and 3D nanoscopy of dynamic actin structures.
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Affiliation(s)
- Rūta Gerasimaitė
- Chromatin Labeling and Imaging Group
- Department of Nanobiophotonics
- Max Planck Institute for Biophysical Chemistry
- Göttingen
- Germany
| | - Jan Seikowski
- Facility for Synthetic Chemistry
- Max Planck Institute for Biophysical Chemistry
- Göttingen
- Germany
| | - Jens Schimpfhauser
- Facility for Synthetic Chemistry
- Max Planck Institute for Biophysical Chemistry
- Göttingen
- Germany
| | - Georgij Kostiuk
- Chromatin Labeling and Imaging Group
- Department of Nanobiophotonics
- Max Planck Institute for Biophysical Chemistry
- Göttingen
- Germany
| | - Tanja Gilat
- Department of Nanobiophotonics
- Max Planck Institute for Biophysical Chemistry
- Göttingen
- Germany
| | - Elisa D'Este
- Optical Microscopy Facility
- Max Planck Institute for Medical Research
- 69120 Heidelberg
- Germany
| | - Sebastian Schnorrenberg
- Department of Nanobiophotonics
- Max Planck Institute for Biophysical Chemistry
- Göttingen
- Germany
| | - Gražvydas Lukinavičius
- Chromatin Labeling and Imaging Group
- Department of Nanobiophotonics
- Max Planck Institute for Biophysical Chemistry
- Göttingen
- Germany
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30
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Lacy MM, Baddeley D, Berro J. Single-molecule turnover dynamics of actin and membrane coat proteins in clathrin-mediated endocytosis. eLife 2019; 8:52355. [PMID: 31855180 PMCID: PMC6977972 DOI: 10.7554/elife.52355] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/18/2019] [Indexed: 12/22/2022] Open
Abstract
Actin dynamics generate forces to deform the membrane and overcome the cell’s high turgor pressure during clathrin-mediated endocytosis (CME) in yeast, but precise molecular details are still unresolved. Our previous models predicted that actin filaments of the endocytic meshwork continually polymerize and disassemble, turning over multiple times during an endocytic event, similar to other actin systems. We applied single-molecule speckle tracking in live fission yeast to directly measure molecular turnover within CME sites for the first time. In contrast with the overall ~20 s lifetimes of actin and actin-associated proteins in endocytic patches, we detected single-molecule residence times around 1 to 2 s, and similarly high turnover rates of membrane-associated proteins in CME. Furthermore, we find heterogeneous behaviors in many proteins’ motions. These results indicate that endocytic proteins turn over up to five times during the formation of an endocytic vesicle, and suggest revising quantitative models of force production.
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Affiliation(s)
- Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Nanobiology Institute, Yale University, West Haven, United States.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, United States
| | - David Baddeley
- Nanobiology Institute, Yale University, West Haven, United States.,Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Nanobiology Institute, Yale University, West Haven, United States.,Department of Cell Biology, Yale University School of Medicine, New Haven, United States
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31
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Lacy MM, Baddeley D, Berro J. Single-molecule turnover dynamics of actin and membrane coat proteins in clathrin-mediated endocytosis. eLife 2019; 8. [PMID: 31855180 DOI: 10.1101/617746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/18/2019] [Indexed: 05/20/2023] Open
Abstract
Actin dynamics generate forces to deform the membrane and overcome the cell's high turgor pressure during clathrin-mediated endocytosis (CME) in yeast, but precise molecular details are still unresolved. Our previous models predicted that actin filaments of the endocytic meshwork continually polymerize and disassemble, turning over multiple times during an endocytic event, similar to other actin systems. We applied single-molecule speckle tracking in live fission yeast to directly measure molecular turnover within CME sites for the first time. In contrast with the overall ~20 s lifetimes of actin and actin-associated proteins in endocytic patches, we detected single-molecule residence times around 1 to 2 s, and similarly high turnover rates of membrane-associated proteins in CME. Furthermore, we find heterogeneous behaviors in many proteins' motions. These results indicate that endocytic proteins turn over up to five times during the formation of an endocytic vesicle, and suggest revising quantitative models of force production.
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Affiliation(s)
- Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
- Nanobiology Institute, Yale University, West Haven, United States
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, United States
| | - David Baddeley
- Nanobiology Institute, Yale University, West Haven, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
- Nanobiology Institute, Yale University, West Haven, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
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32
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A general strategy to develop cell permeable and fluorogenic probes for multicolour nanoscopy. Nat Chem 2019; 12:165-172. [PMID: 31792385 DOI: 10.1038/s41557-019-0371-1] [Citation(s) in RCA: 193] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 10/09/2019] [Indexed: 01/19/2023]
Abstract
Live-cell fluorescence nanoscopy is a powerful tool to study cellular biology on a molecular scale, yet its use is held back by the paucity of suitable fluorescent probes. Fluorescent probes based on regular fluorophores usually suffer from a low cell permeability and an unspecific background signal. Here we report a general strategy to transform regular fluorophores into fluorogenic probes with an excellent cell permeability and a low unspecific background signal. Conversion of a carboxyl group found in rhodamines and related fluorophores into an electron-deficient amide does not affect the spectroscopic properties of the fluorophore, but allows us to rationally tune the dynamic equilibrium between two different forms: a fluorescent zwitterion and a non-fluorescent, cell-permeable spirolactam. Furthermore, the equilibrium generally shifts towards the fluorescent form when the probe binds to its cellular targets. The resulting increase in fluorescence can be up to 1,000-fold. Using this simple design principle, we created fluorogenic probes in various colours for different cellular targets for wash-free, multicolour, live-cell nanoscopy.
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33
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Chia HE, Marsh ENG, Biteen JS. Extending fluorescence microscopy into anaerobic environments. Curr Opin Chem Biol 2019; 51:98-104. [DOI: 10.1016/j.cbpa.2019.05.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 04/22/2019] [Accepted: 05/13/2019] [Indexed: 12/01/2022]
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34
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Eckels EC, Tapia-Rojo R, Rivas-Pardo JA, Fernández JM. The Work of Titin Protein Folding as a Major Driver in Muscle Contraction. Annu Rev Physiol 2019; 80:327-351. [PMID: 29433413 DOI: 10.1146/annurev-physiol-021317-121254] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Single-molecule atomic force microscopy and magnetic tweezers experiments have demonstrated that titin immunoglobulin (Ig) domains are capable of folding against a pulling force, generating mechanical work that exceeds that produced by a myosin motor. We hypothesize that upon muscle activation, formation of actomyosin cross bridges reduces the force on titin, causing entropic recoil of the titin polymer and triggering the folding of the titin Ig domains. In the physiological force range of 4-15 pN under which titin operates in muscle, the folding contraction of a single Ig domain can generate 200% of the work of entropic recoil and occurs at forces that exceed the maximum stalling force of single myosin motors. Thus, titin operates like a mechanical battery, storing elastic energy efficiently by unfolding Ig domains and delivering the charge back by folding when the motors are activated during a contraction. We advance the hypothesis that titin folding and myosin activation act as inextricable partners during muscle contraction.
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Affiliation(s)
- Edward C Eckels
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; , .,Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Medical Center, New York, NY 10032, USA
| | - Rafael Tapia-Rojo
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; ,
| | | | - Julio M Fernández
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; ,
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35
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Wollman AJM, Hedlund EG, Shashkova S, Leake MC. Towards mapping the 3D genome through high speed single-molecule tracking of functional transcription factors in single living cells. Methods 2019; 170:82-89. [PMID: 31252059 PMCID: PMC6971689 DOI: 10.1016/j.ymeth.2019.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/22/2019] [Indexed: 10/26/2022] Open
Abstract
How genomic DNA is organized in the nucleus is a long-standing question. We describe a single-molecule bioimaging method utilizing super-localization precision coupled to fully quantitative image analysis tools, towards determining snapshots of parts of the 3D genome architecture of model eukaryote budding yeast Saccharomyces cerevisiae with exceptional millisecond time resolution. We employ astigmatism imaging to enable robust extraction of 3D position data on genomically encoded fluorescent protein reporters that bind to DNA. Our relatively straightforward method enables snippets of 3D architectures of likely single genome conformations to be resolved captured via DNA-sequence specific binding proteins in single functional living cells.
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Affiliation(s)
- Adam J M Wollman
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Erik G Hedlund
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Sviatlana Shashkova
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Mark C Leake
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
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36
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Grimm F, Nizamov S, Belov VN. Green-Emitting Rhodamine Dyes for Vital Labeling of Cell Organelles Using STED Super-Resolution Microscopy. Chembiochem 2019; 20:2248-2254. [PMID: 31050112 DOI: 10.1002/cbic.201900177] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/02/2019] [Indexed: 12/12/2022]
Abstract
Fluorescence microscopy reveals the localization, spatial distribution, and temporal dynamics of the specifically labeled organelles in living cells. Labeling with exogenous conjugates prepared from fluorescent dyes and small molecules (ligands) is an attractive alternative to the use of fluorescent proteins, but proved to be challenging due to insufficient cell-permeability of the probes, unspecific staining, or low dye brightness. We evaluated four green-emitting rhodamine dyes and their conjugates intended for the specific labeling of lysosomes, mitochondria, tubulin, and actin in living cells. The imaging performance of the probes in living human fibroblasts has been studied by using confocal and stimulated emission depletion (STED) super-resolution microscopy with a commercial 595 nm STED laser. Two bright and photostable dyes (LIVE 510 and LIVE 515) provide specific and versatile staining.
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Affiliation(s)
- Florian Grimm
- Abberior GmbH, Hans-Adolf-Krebs-Weg 1, 37077, Göttingen, Germany
| | - Shamil Nizamov
- Abberior GmbH, Hans-Adolf-Krebs-Weg 1, 37077, Göttingen, Germany
| | - Vladimir N Belov
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
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37
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Erdmann RS, Baguley SW, Richens JH, Wissner RF, Xi Z, Allgeyer ES, Zhong S, Thompson AD, Lowe N, Butler R, Bewersdorf J, Rothman JE, St Johnston D, Schepartz A, Toomre D. Labeling Strategies Matter for Super-Resolution Microscopy: A Comparison between HaloTags and SNAP-tags. Cell Chem Biol 2019; 26:584-592.e6. [PMID: 30745239 PMCID: PMC6474801 DOI: 10.1016/j.chembiol.2019.01.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 07/13/2018] [Accepted: 01/07/2019] [Indexed: 12/22/2022]
Abstract
Super-resolution microscopy requires that subcellular structures are labeled with bright and photostable fluorophores, especially for live-cell imaging. Organic fluorophores may help here as they can yield more photons-by orders of magnitude-than fluorescent proteins. To achieve molecular specificity with organic fluorophores in live cells, self-labeling proteins are often used, with HaloTags and SNAP-tags being the most common. However, how these two different tagging systems compare with each other is unclear, especially for stimulated emission depletion (STED) microscopy, which is limited to a small repertoire of fluorophores in living cells. Herein, we compare the two labeling approaches in confocal and STED imaging using various proteins and two model systems. Strikingly, we find that the fluorescent signal can be up to 9-fold higher with HaloTags than with SNAP-tags when using far-red rhodamine derivatives. This result demonstrates that the labeling strategy matters and can greatly influence the duration of super-resolution imaging.
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Affiliation(s)
- Roman S. Erdmann
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA,Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, USA
| | - Stephanie Wood Baguley
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Jennifer H. Richens
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Rebecca F. Wissner
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, USA
| | - Zhiqun Xi
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Edward S. Allgeyer
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Sheng Zhong
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | | | - Nicholas Lowe
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Richard Butler
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA,Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, USA
| | - James E. Rothman
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Daniel St Johnston
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Alanna Schepartz
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA.
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38
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Ayele TM, Knutson SD, Ellipilli S, Hwang H, Heemstra JM. Fluorogenic Photoaffinity Labeling of Proteins in Living Cells. Bioconjug Chem 2019; 30:1309-1313. [PMID: 30978287 DOI: 10.1021/acs.bioconjchem.9b00203] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Genetically encoded fluorescent proteins or small-molecule probes that recognize specific protein binding partners can be used to label proteins to study their localization and function with fluorescence microscopy. However, these approaches are limited in signal-to-background resolution and the ability to temporally control labeling. Herein, we describe a covalent protein labeling technique using a fluorogenic malachite green probe functionalized with a photoreactive cross-linker. This enables a controlled covalent attachment to a genetically encodable fluorogen activating protein (FAP) with low background signal. We demonstrate covalent labeling of a protein in vitro as well as in live mammalian cells. This method is straightforward, displays high labeling specificity, and results in improved signal-to-background ratios in photoaffinity labeling of target proteins. Additionally, this probe provides temporal control over reactivity, enabling future applications in real-time monitoring of cellular events.
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Affiliation(s)
- Tewoderos M Ayele
- Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States
| | - Steve D Knutson
- Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States
| | - Satheesh Ellipilli
- Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States
| | - Hyun Hwang
- Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States
| | - Jennifer M Heemstra
- Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States
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39
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Sezgin E, Schneider F, Galiani S, Urbančič I, Waithe D, Lagerholm BC, Eggeling C. Measuring nanoscale diffusion dynamics in cellular membranes with super-resolution STED-FCS. Nat Protoc 2019; 14:1054-1083. [PMID: 30842616 DOI: 10.1038/s41596-019-0127-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/04/2019] [Indexed: 11/08/2022]
Abstract
Super-resolution microscopy techniques enable optical imaging in live cells with unprecedented spatial resolution. They unfortunately lack the temporal resolution required to directly investigate cellular dynamics at scales sufficient to measure molecular diffusion. These fast time scales are, on the other hand, routinely accessible by spectroscopic techniques such as fluorescence correlation spectroscopy (FCS). To enable the direct investigation of fast dynamics at the relevant spatial scales, FCS has been combined with super-resolution stimulated emission depletion (STED) microscopy. STED-FCS has been applied in point or scanning mode to reveal nanoscale diffusion behavior of molecules in live cells. In this protocol, we describe the technical details of performing point STED-FCS (pSTED-FCS) and scanning STED-FCS (sSTED-FCS) measurements, from calibration and sample preparation to data acquisition and analysis. We give particular emphasis to 2D diffusion dynamics in cellular membranes, using molecules tagged with organic fluorophores. These measurements can be accomplished within 4-6 h by those proficient in fluorescence imaging.
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Affiliation(s)
- Erdinc Sezgin
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.
| | - Falk Schneider
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Silvia Galiani
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Iztok Urbančič
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Solid State Physics Department, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Dominic Waithe
- Wolfson Imaging Centre, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - B Christoffer Lagerholm
- Wolfson Imaging Centre, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Christian Eggeling
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.
- Wolfson Imaging Centre, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.
- Institute of Applied Optics, Friedrich-Schiller-University Jena, Jena, Germany.
- Department of Biophysical Imaging, Leibniz Institute of Photonic Technology e.V., Jena, Germany.
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40
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Jung KH, Kim SF, Liu Y, Zhang X. A Fluorogenic
AggTag
Method Based on Halo‐ and SNAP‐Tags to Simultaneously Detect Aggregation of Two Proteins in Live Cells. Chembiochem 2019; 20:1078-1087. [DOI: 10.1002/cbic.201800782] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Kwan Ho Jung
- Department of ChemistryThe Pennsylvania State University University Park PA 16802 USA
| | - Sojung F. Kim
- Department of ChemistryThe Pennsylvania State University University Park PA 16802 USA
| | - Yu Liu
- Department of ChemistryThe Pennsylvania State University University Park PA 16802 USA
| | - Xin Zhang
- Department of ChemistryThe Pennsylvania State University University Park PA 16802 USA
- Department of Biochemistry and Molecular BiologyThe Pennsylvania State University University Park PA 16802 USA
- The Huck Institutes of the Life SciencesThe Pennsylvania State University University Park PA 16802 USA
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41
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Bucevičius J, Keller-Findeisen J, Gilat T, Hell SW, Lukinavičius G. Rhodamine-Hoechst positional isomers for highly efficient staining of heterochromatin. Chem Sci 2019; 10:1962-1970. [PMID: 30881625 PMCID: PMC6385482 DOI: 10.1039/c8sc05082a] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 12/11/2018] [Indexed: 12/13/2022] Open
Abstract
Hoechst conjugates to fluorescent dyes are popular DNA stains for live-cell imaging, but the relationship between their structure and performance remains elusive. This study of carboxyrhodamine-Hoechst 33258 conjugates reveals that a minimal change in the attachment point of the dye has dramatic effects on the properties of the final probe. All tested 6'-carboxyl dye-containing probes exhibited dual-mode binding to DNA and formed a dimmer complex at high DNA concentrations. The 5'-carboxyl dye-containing probes exhibited single-mode binding to DNA which translated into increased brightness and lower cytotoxicity. Up to 10-fold brighter nuclear staining by the newly developed probes allowed acquisition of stimulated emission depletion (STED) nanoscopy images of outstanding quality in living and fixed cells. Therefore we were able to estimate a diameter of ∼155 nm of the heterochromatin exclusion zones in the nuclear pore region in living cells and intact chicken erythrocytes and to localize telomeres relative to heterochromatin in living U-2 OS cells. Employing the highly efficient probes for two-color STED allowed visualization of DNA and tubulin structures in intact nucleated erythrocytes - a system where imaging is greatly hampered by high haemoglobin absorbance.
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Affiliation(s)
- Jonas Bucevičius
- Department of NanoBiophotonics , Max Planck Institute for Biophysical Chemistry , Am Fassberg 11 , Göttingen , 37077 , Germany .
| | - Jan Keller-Findeisen
- Department of NanoBiophotonics , Max Planck Institute for Biophysical Chemistry , Am Fassberg 11 , Göttingen , 37077 , Germany .
| | - Tanja Gilat
- Department of NanoBiophotonics , Max Planck Institute for Biophysical Chemistry , Am Fassberg 11 , Göttingen , 37077 , Germany .
| | - Stefan W Hell
- Department of NanoBiophotonics , Max Planck Institute for Biophysical Chemistry , Am Fassberg 11 , Göttingen , 37077 , Germany .
| | - Gražvydas Lukinavičius
- Department of NanoBiophotonics , Max Planck Institute for Biophysical Chemistry , Am Fassberg 11 , Göttingen , 37077 , Germany .
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42
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Oliveira Paiva AM, Friggen AH, Qin L, Douwes R, Dame RT, Smits WK. The Bacterial Chromatin Protein HupA Can Remodel DNA and Associates with the Nucleoid in Clostridium difficile. J Mol Biol 2019; 431:653-672. [PMID: 30633871 DOI: 10.1016/j.jmb.2019.01.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/19/2018] [Accepted: 01/02/2019] [Indexed: 12/15/2022]
Abstract
The maintenance and organization of the chromosome plays an important role in the development and survival of bacteria. Bacterial chromatin proteins are architectural proteins that bind DNA and modulate its conformation, and by doing so affect a variety of cellular processes. No bacterial chromatin proteins of Clostridium difficile have been characterized to date. Here, we investigate aspects of the C. difficile HupA protein, a homologue of the histone-like HU proteins of Escherichia coli. HupA is a 10-kDa protein that is present as a homodimer in vitro and self-interacts in vivo. HupA co-localizes with the nucleoid of C. difficile. It binds to the DNA without a preference for the DNA G + C content. Upon DNA binding, HupA induces a conformational change in the substrate DNA in vitro and leads to compaction of the chromosome in vivo. The present study is the first to characterize a bacterial chromatin protein in C. difficile and opens the way to study the role of chromosomal organization in DNA metabolism and on other cellular processes in this organism.
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Affiliation(s)
- Ana M Oliveira Paiva
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Annemieke H Friggen
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Liang Qin
- Faculty of Science, Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Roxanne Douwes
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands
| | - Remus T Dame
- Faculty of Science, Leiden Institute of Chemistry, Leiden University, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, the Netherlands; Center for Microbial Cell Biology, Leiden, the Netherlands.
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43
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Mondal S, Verma A, Saha S. Conformationally Restricted Triarylmethanes: Synthesis, Photophysical Studies, and Applications. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800971] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Sankalan Mondal
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi India
| | - Abhineet Verma
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi India
| | - Satyen Saha
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi India
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44
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Kapanidis AN, Lepore A, El Karoui M. Rediscovering Bacteria through Single-Molecule Imaging in Living Cells. Biophys J 2018; 115:190-202. [PMID: 29680157 PMCID: PMC6050715 DOI: 10.1016/j.bpj.2018.03.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/16/2018] [Accepted: 03/26/2018] [Indexed: 12/23/2022] Open
Abstract
Bacteria are microorganisms central to health and disease, serving as important model systems for our understanding of molecular mechanisms and for developing new methodologies and vehicles for biotechnology. In the past few years, our understanding of bacterial cell functions has been enhanced substantially by powerful single-molecule imaging techniques. Using single fluorescent molecules as a means of breaking the optical microscopy limit, we can now reach resolutions of ∼20 nm inside single living cells, a spatial domain previously accessible only by electron microscopy. One can follow a single bacterial protein complex as it performs its functions and directly observe intricate cellular structures as they move and reorganize during the cell cycle. This toolbox enables the use of in vivo quantitative biology by counting molecules, characterizing their intracellular location and mobility, and identifying functionally distinct molecular distributions. Crucially, this can all be achieved while imaging large populations of cells, thus offering detailed views of the heterogeneity in bacterial communities. Here, we examine how this new scientific domain was born and discuss examples of applications to bacterial cellular mechanisms as well as emerging trends and applications.
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Affiliation(s)
- Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, United Kingdom.
| | - Alessia Lepore
- Institute of Cell Biology and SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Meriem El Karoui
- Institute of Cell Biology and SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom.
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Stoldt S, Wenzel D, Kehrein K, Riedel D, Ott M, Jakobs S. Spatial orchestration of mitochondrial translation and OXPHOS complex assembly. Nat Cell Biol 2018; 20:528-534. [PMID: 29662179 DOI: 10.1038/s41556-018-0090-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/20/2018] [Indexed: 12/11/2022]
Abstract
Oxidative phosphorylation (OXPHOS) is vital for the regeneration of the vast majority of ATP in eukaryotic cells 1 . OXPHOS is carried out by large multi-subunit protein complexes in the cristae membranes, which are invaginations of the mitochondrial inner membrane. The OXPHOS complexes are a mix of subunits encoded in the nuclear and mitochondrial genomes. Thus, the assembly of these dual-origin complexes is an enormous logistical challenge for the cell. Using super-resolution microscopy (nanoscopy) and quantitative cryo-immunogold electron microscopy, we determined where specific transcripts are translated and where distinct assembly steps of the dual-origin complexes in the yeast Saccharomyces cerevisiae occur. Our data indicate that the mitochondrially encoded proteins of complex III and complex IV are preferentially inserted in different sites of the inner membrane than those of complex V. We further demonstrate that the early, but not the late, assembly steps of complex III and complex IV occur preferentially in the inner boundary membrane. By contrast, all steps of complex V assembly occur mainly in the cristae membranes. Thus, OXPHOS complex assembly is spatially well orchestrated, probably representing an unappreciated regulatory layer in mitochondrial biogenesis.
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Affiliation(s)
- Stefan Stoldt
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Wenzel
- Laboratory of Electron Microscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Kirsten Kehrein
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Dietmar Riedel
- Laboratory of Electron Microscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Stefan Jakobs
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany. .,Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.
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Abstract
Superresolution microscopy has become increasingly widespread over the past 5 years and allows users to image biological processes below the diffraction limit of traditional fluorescence microscopy where resolution is restricted to approximately 250 nm. Superresolution refers to a wide range of techniques which employ different approaches to circumvent the diffraction limit. Two of these approaches, structured illumination microscopy (SIM) and single-molecule localization microscopy (SMLM), which provide a doubling and tenfold increase in resolution respectively, are dominating the field. This is partly because of the insights into biology they offer and partly because of their commercialization by the main microscope manufacturers. This chapter provides background to the two techniques, practical considerations for their use, and protocols for their application to platelet biology.
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Abstract
Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.
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Affiliation(s)
- Franz-Josef Meyer-Almes
- Department of Chemical Engineering and Biotechnology, University of Applied Sciences Darmstadt, Haardtring 100, D-64295 Darmstadt, Germany
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Wichner SM, Mann VR, Powers AS, Segal MA, Mir M, Bandaria J, DeWitt MA, Darzacq X, Yildiz A, Cohen BE. Covalent Protein Labeling and Improved Single-Molecule Optical Properties of Aqueous CdSe/CdS Quantum Dots. ACS NANO 2017; 11:6773-6781. [PMID: 28618223 PMCID: PMC5891212 DOI: 10.1021/acsnano.7b01470] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Semiconductor quantum dots (QDs) have proven to be superior probes for single-molecule imaging compared to organic or genetically encoded fluorophores, but they are limited by difficulties in protein targeting, their larger size, and on-off blinking. Here, we report compact aqueous CdSe/CdS QDs with significantly improved bioconjugation efficiency and superior single-molecule optical properties. We have synthesized covalent protein labeling ligands (i.e., SNAP tags) that are optimized for nanoparticle use, and QDs functionalized with these ligands label SNAP-tagged proteins ∼10-fold more efficiently than existing SNAP ligands. Single-molecule analysis of these QDs shows 99% of time spent in the fluorescent on-state, ∼4-fold higher quantum efficiency than standard CdSe/ZnS QDs, and 350 million photons detected before photobleaching. Bright signals of these QDs enable us to track the stepping movement of a kinesin motor in vitro, and the improved labeling efficiency enables tracking of single kinesins in live cells.
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Affiliation(s)
- Sara M. Wichner
- Department of Chemistry, University of California at Berkeley, Berkeley CA 94720 USA
| | - Victor R. Mann
- Department of Chemistry, University of California at Berkeley, Berkeley CA 94720 USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA
| | - Alexander S. Powers
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA
| | - Maya A. Segal
- Department of Chemistry, University of California at Berkeley, Berkeley CA 94720 USA
| | - Mustafa Mir
- Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley CA 94720 USA
| | - Jigar Bandaria
- Department of Physics, University of California at Berkeley, Berkeley CA 94720 USA
| | - Mark A. DeWitt
- Biophysics Graduate Group, University of California at Berkeley, Berkeley CA 94720 USA
| | - Xavier Darzacq
- Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley CA 94720 USA
| | - Ahmet Yildiz
- Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley CA 94720 USA
- Department of Physics, University of California at Berkeley, Berkeley CA 94720 USA
- Biophysics Graduate Group, University of California at Berkeley, Berkeley CA 94720 USA
- Corresponding authors: ,
| | - Bruce E. Cohen
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA
- Corresponding authors: ,
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Wang C, Taki M, Sato Y, Fukazawa A, Higashiyama T, Yamaguchi S. Super-Photostable Phosphole-Based Dye for Multiple-Acquisition Stimulated Emission Depletion Imaging. J Am Chem Soc 2017; 139:10374-10381. [PMID: 28741935 DOI: 10.1021/jacs.7b04418] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As stimulated emission depletion (STED) microscopy can provide structural details of cells with an optical resolution beyond the diffraction limit, it has become an indispensable tool in cell biology. However, the intense STED laser beam usually causes rapid photobleaching of the employed fluorescent dyes, which significantly limits the utility of STED microscopy from a practical perspective. Herein we report a new design of super-photostable dye, PhoxBright 430 (PB430), comprising a fully ring-fused π-conjugated skeleton with an electron-accepting phosphole P-oxide unit. We previously developed a super-photostable dye C-Naphox by combining the phosphole unit with an electron-donating triphenylamine moiety. In PB430, removal of the amino group alters the transition type from intramolecular charge transfer character to π-π* transition character, which gives rise to intense fluorescence insensitive to molecular environment in terms of fluorescence colors and intensity, and bright fluorescence even in aqueous media. PB430 also furnishes high solubility in water, and is capable of labeling proteins with maintaining high fluorescence quantum yields. This dye exhibits outstanding resistance to photoirradiation even under the STED conditions and allows continuous acquisition of STED images. Indeed, using a PB430-conjugated antibody, we succeed in attaining a 3-D reconstruction of super-resolution STED images as well as photostability-based multicolor STED imaging of fluorescently labeled cytoskeletal structures.
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Affiliation(s)
- Chenguang Wang
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Furo, Chikusa, Nagoya 464-8501, Japan
| | - Masayasu Taki
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Furo, Chikusa, Nagoya 464-8501, Japan
| | - Yoshikatsu Sato
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Furo, Chikusa, Nagoya 464-8501, Japan
| | - Aiko Fukazawa
- Department of Chemistry, Graduate School of Science, Nagoya University , Furo, Chikusa, Nagoya 464-8602, Japan
| | - Tetsuya Higashiyama
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Furo, Chikusa, Nagoya 464-8501, Japan.,Division of Biological Science, Graduate School of Science, Nagoya University , Furo, Chikusa, Nagoya 464-8602, Japan
| | - Shigehiro Yamaguchi
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Furo, Chikusa, Nagoya 464-8501, Japan.,Department of Chemistry, Graduate School of Science, Nagoya University , Furo, Chikusa, Nagoya 464-8602, Japan
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50
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Lacy MM, Baddeley D, Berro J. Single-molecule imaging of the BAR-domain protein Pil1p reveals filament-end dynamics. Mol Biol Cell 2017; 28:2251-2259. [PMID: 28659415 PMCID: PMC5555653 DOI: 10.1091/mbc.e17-04-0238] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 06/22/2017] [Indexed: 12/21/2022] Open
Abstract
Molecular assemblies can have highly heterogeneous dynamics within the cell, but the limitations of conventional fluorescence microscopy can mask nanometer-scale features. Here we adapt a single-molecule strategy to perform single-molecule recovery after photobleaching (SRAP) within dense macromolecular assemblies to reveal and characterize binding and unbinding dynamics within such assemblies. We applied this method to study the eisosome, a stable assembly of BAR-domain proteins on the cytoplasmic face of the plasma membrane in fungi. By fluorescently labeling only a small fraction of cellular Pil1p, the main eisosome BAR-domain protein in fission yeast, we visualized whole eisosomes and, after photobleaching, localized recruitment of new Pil1p molecules with ∼30-nm precision. Comparing our data to computer simulations, we show that Pil1p exchange occurs specifically at eisosome ends and not along their core, supporting a new model of the eisosome as a dynamic filament. This result is the first direct observation of any BAR-domain protein dynamics in vivo under physiological conditions consistent with the oligomeric filaments reported from in vitro experiments.
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Affiliation(s)
- Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520.,Nanobiology Institute, Yale University, West Haven, CT 06516.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520
| | - David Baddeley
- Nanobiology Institute, Yale University, West Haven, CT 06516.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520.,Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520 .,Nanobiology Institute, Yale University, West Haven, CT 06516.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520
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