1
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Hernandez AC, Ortiz S, Betancur LI, Dojčilović R, Picco A, Kaksonen M, Oliva B, Gallego O. PyF2F: a robust and simplified fluorophore-to-fluorophore distance measurement tool for Protein interactions from Imaging Complexes after Translocation experiments. NAR Genom Bioinform 2024; 6:lqae027. [PMID: 38486885 PMCID: PMC10939353 DOI: 10.1093/nargab/lqae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/31/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
Structural knowledge of protein assemblies in their physiological environment is paramount to understand cellular functions at the molecular level. Protein interactions from Imaging Complexes after Translocation (PICT) is a live-cell imaging technique for the structural characterization of macromolecular assemblies in living cells. PICT relies on the measurement of the separation between labelled molecules using fluorescence microscopy and cell engineering. Unfortunately, the required computational tools to extract molecular distances involve a variety of sophisticated software programs that challenge reproducibility and limit their implementation to highly specialized researchers. Here we introduce PyF2F, a Python-based software that provides a workflow for measuring molecular distances from PICT data, with minimal user programming expertise. We used a published dataset to validate PyF2F's performance.
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Affiliation(s)
- Altair C Hernandez
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona 08005, Catalonia, Spain
| | - Sebastian Ortiz
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona 08005, Catalonia, Spain
| | - Laura I Betancur
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona 08005, Catalonia, Spain
| | - Radovan Dojčilović
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona 08005, Catalonia, Spain
| | - Andrea Picco
- Department of Biochemistry, University of Geneva, 1205 Genève, Switzerland
| | - Marko Kaksonen
- Department of Biochemistry, University of Geneva, 1205 Genève, Switzerland
| | - Baldo Oliva
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona 08005, Catalonia, Spain
| | - Oriol Gallego
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona 08005, Catalonia, Spain
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2
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Croquette V, Orero JV, Rieu M, Allemand JF. Magnetic tweezers principles and promises. Methods Enzymol 2024; 694:1-49. [PMID: 38492947 DOI: 10.1016/bs.mie.2024.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
Magnetic tweezers have become popular with the outbreak of single molecule micromanipulation: catching a single molecule of DNA, RNA or a single protein and applying mechanical constrains using micron-size magnetic beads and magnets turn out to be easy. Various factors have made this possible: the fact that manufacturers have been preparing these beads to catch various biological entities-the ease of use provided by magnets which apply a force or a torque at a distance thus inside a flow cell-some chance: since the forces so generated are in the right range to stretch a single molecule. This is a little less true for torque. Finally, one feature which also appears very important is the simplicity of their calibration using Brownian motion. Here we start by describing magnetic tweezers used routinely in our laboratory where we have tried to develop a device as simple as possible so that the experimentalist can really focus on the biological aspect of the biomolecules that he/she is interested in. We discuss the implications of the various components and their important features. Next, we summarize what is easy to achieve and what is less easy. Then we refer to contributions by other groups who have brought valuable insights to improve magnetic tweezers.
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Affiliation(s)
- Vincent Croquette
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France; ESPCI Paris, Université PSL, Paris, France.
| | - Jessica Valle Orero
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France; The American University of Paris, Paris, France
| | - Martin Rieu
- Department of Physics, New Biochemistry Building, University of Oxford, South Parks Road, Oxford, United Kingdom
| | - Jean-François Allemand
- Laboratoire de Physique de l'École normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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3
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Ye R, Sun X, Mao X, Alfonso FS, Baral S, Liu C, Coates GW, Chen P. Optical sequencing of single synthetic polymers. Nat Chem 2024; 16:210-217. [PMID: 37945834 DOI: 10.1038/s41557-023-01363-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 10/06/2023] [Indexed: 11/12/2023]
Abstract
Microscopic sequences of synthetic polymers play crucial roles in the polymer properties, but are generally unknown and inaccessible to traditional measurements. Here we report real-time optical sequencing of single synthetic copolymer chains under living polymerization conditions. We achieve this by carrying out multi-colour imaging of polymer growth by single catalysts at single-monomer resolution using CREATS (coupled reaction approach toward super-resolution imaging). CREATS makes a reaction effectively fluorogenic, enabling single-molecule localization microscopy of chemical reactions at higher reactant concentrations. Our data demonstrate that the chain propagation kinetics of surface-grafted polymerization contains temporal fluctuations with a defined memory time (which can be attributed to neighbouring monomer interactions) and chain-length dependence (due to surface electrostatic effects). Furthermore, the microscopic sequences of individual copolymers reveal their tendency to form block copolymers, and, more importantly, quantify the size distribution of individual blocks for comparison with theoretically random copolymers. Such sequencing capability paves the way for single-chain-level structure-function correlation studies of synthetic polymers.
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Affiliation(s)
- Rong Ye
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
- Department of Chemical Engineering and Catalysis Science and Technology Institute, University of Michigan, Ann Arbor, MI, USA
| | - Xiangcheng Sun
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
- Department of Chemical Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Xianwen Mao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
- Department of Materials Science and Engineering, Institute of Functional Intelligent Materials, and Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore
| | - Felix S Alfonso
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Susil Baral
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
- Department of Chemistry, Illinois State University, Normal, IL, USA
| | - Chunming Liu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
- School of Polymer Science and Polymer Engineering and Department of Chemistry, University of Akron, Akron, OH, USA
| | - Geoffrey W Coates
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Peng Chen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
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4
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Xu L, Ye R, Mavrikakis M, Chen P. Molecular-scale Insights into Cooperativity Switching of xTAB Adsorption on Gold Nanoparticles. ACS CENTRAL SCIENCE 2024; 10:65-76. [PMID: 38292618 PMCID: PMC10823513 DOI: 10.1021/acscentsci.3c01075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/12/2023] [Accepted: 11/27/2023] [Indexed: 02/01/2024]
Abstract
Quantifying adsorption behaviors is crucial for various applications such as catalysis, separation, and sensing, yet it is generally challenging to access in solution. Here, we report a combined experimental and computational study of the adsorption behaviors of alkyl-trimethylammonium bromides (xTAB), a class of ligands important for colloidal nanoparticle stabilization and shape control, with various alkyl chain lengths x on Au nanoparticles. We use density functional theory (DFT) to calculate xTAB binding energies on Au{111} and Au{110} surfaces with standing-up and lying-down configurations, which provides insights into the adsorption affinity and cooperativity differences of xTAB on these two facets. We demonstrate the key role of van der Waals interactions in determining the xTAB adsorption behavior. These computational results predict and explain the experimental discovery of xTAB's adsorption behavior switch from stronger affinity, negative cooperativity to weaker affinity, positive cooperativity when the concentration of xTAB increases in solution. We also show that in the standing-up configuration, bilayer adsorption may occur on both facets, which can lead to different differential binding energies and consequently adsorption crossover between the two facets when the ligand concentration increases. Our combined experimental and computational approaches demonstrate a paradigm for gaining molecular-scale insights into adsorbate-surface interactions.
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Affiliation(s)
- Lang Xu
- Department
of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Rong Ye
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Manos Mavrikakis
- Department
of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Peng Chen
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
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5
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van den Wildenberg SMJL, Prevo B, Peterman EJG. A Brief Introduction to Single-Molecule Fluorescence Methods. Methods Mol Biol 2024; 2694:111-132. [PMID: 37824002 DOI: 10.1007/978-1-0716-3377-9_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
One of the most popular single-molecule approaches in biological science is single-molecule fluorescence microscopy, which will be the subject of the following section of this volume. Fluorescence methods provide the sensitivity required to study biology on the single-molecule level, but they also allow access to useful measurable parameters on time and length scales relevant for the biomolecular world. Before several detailed experimental approaches will be addressed, we will first give a general overview of single-molecule fluorescence microscopy. We start with discussing the phenomenon of fluorescence in general and the history of single-molecule fluorescence microscopy. Next, we will review fluorescent probes in more detail and the equipment required to visualize them on the single-molecule level. We will end with a description of parameters measurable with such approaches, ranging from protein counting and tracking, single-molecule localization super-resolution microscopy, to distance measurements with Förster resonance energy transfer and orientation measurements with fluorescence polarization.
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Affiliation(s)
- Siet M J L van den Wildenberg
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, Clermont-Ferrand, France
- Université Clermont Auvergne, CNRS/IN2P3, Laboratoire de Physique de Clermont, Clermont-Ferrand, France
| | - Bram Prevo
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Erwin J G Peterman
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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6
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Embacher PA, Germanova TE, Roscioli E, McAinsh AD, Burroughs NJ. Bayesian inference of multi-point macromolecular architecture mixtures at nanometre resolution. PLoS Comput Biol 2022; 18:e1010765. [PMID: 36574448 PMCID: PMC9829179 DOI: 10.1371/journal.pcbi.1010765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 01/09/2023] [Accepted: 11/28/2022] [Indexed: 12/29/2022] Open
Abstract
Gaussian spot fitting methods have significantly extended the spatial range where fluorescent microscopy can be used, with recent techniques approaching nanometre (nm) resolutions. However, small inter-fluorophore distances are systematically over-estimated for typical molecular scales. This bias can be corrected computationally, but current algorithms are limited to correcting distances between pairs of fluorophores. Here we present a flexible Bayesian computational approach that infers the distances and angles between multiple fluorophores and has several advantages over these previous methods. Specifically it improves confidence intervals for small lengths, estimates measurement errors of each fluorophore individually and infers the correlations between polygon lengths. The latter is essential for determining the full multi-fluorophore 3D architecture. We further developed the algorithm to infer the mixture composition of a heterogeneous population of multiple polygon states. We use our algorithm to analyse the 3D architecture of the human kinetochore, a macro-molecular complex that is essential for high fidelity chromosome segregation during cell division. Using triple fluorophore image data we unravel the mixture of kinetochore states during human mitosis, inferring the conformation of microtubule attached and unattached kinetochores and their proportions across mitosis. We demonstrate that the attachment conformation correlates with intersister tension and sister alignment to the metaphase plate.
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Affiliation(s)
- Peter A. Embacher
- Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom
| | - Tsvetelina E. Germanova
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Emanuele Roscioli
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Andrew D. McAinsh
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Nigel J. Burroughs
- Mathematics Institute and Zeeman Institute, University of Warwick, Coventry, United Kingdom
- * E-mail:
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7
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Synergistic interplay between photoisomerization and photoluminescence in a light-driven rotary molecular motor. Nat Commun 2022; 13:5765. [PMID: 36180434 PMCID: PMC9525625 DOI: 10.1038/s41467-022-33177-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/06/2022] [Indexed: 12/03/2022] Open
Abstract
Photoactuators and photoluminescent dyes utilize light to perform mechanical motion and undergo spontaneous radiation emission, respectively. Combining these two functionalities in a single molecule would benefit the construction of advanced molecular machines. Due to the possible detrimental interaction between the two light-dependent functional parts, the design of hybrid systems featuring both functions in parallel remains highly challenging. Here, we develop a light-driven rotary molecular motor with an efficient photoluminescent dye chemically attached to the motor, not compromising its motor function. This molecular system shows efficient rotary motion and bright photoluminescence, and these functions can be addressed by a proper choice of excitation wavelengths and solvents. The moderate interaction between the two parts generates synergistic effects, which are beneficial for lower-energy excitation and chirality transfer from the motor to the photoluminescent dye. Our results provide prospects towards photoactive multifunctional systems capable of carrying out molecular rotary motion and tracking its location in a complex environment. Combining photofunctionalities in a single molecule is challenging due to inherent detrimental interactions. Here, the authors construct a molecular motor that exhibits photoinduced rotary motion together with bright photoluminescence.
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8
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Chang J, Arai T, Kuramochi M, Inamasu R, Lee Z, Ohkubo T, Mio K, Sasaki YC. Dynamic observations of various oligomers in amyloid β isoforms using laboratory diffracted X-ray blinking. Biochem Biophys Rep 2022; 31:101298. [PMID: 35794960 PMCID: PMC9251562 DOI: 10.1016/j.bbrep.2022.101298] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/08/2022] [Accepted: 06/08/2022] [Indexed: 11/02/2022] Open
Abstract
Acceleration of societal ageing has increased the global incidence of geriatric diseases such as Alzheimer's disease (AD), and the demands for proper diagnosis and monitoring of those diseases are also increasing daily. We utilized diffracted X-ray blinking (DXB) for amyloid β (Aβ) isoforms, which are thought to be closely related to AD, to discriminate among the dynamics of individual particles in early and long-term oligomerisation and aggregation inhibiting environments. Among the various Aβ isoforms, the dynamics of Aβ (1–42), which is known to be the most toxic form, were the slowest (the dynamics were lower by 78% com-pared with short-term incubation), and the dynamics were restored (the dynamics increased by 105% compared with normal aggregation) in an environment that suppressed oligomerisation of Aβ (1–42). It has been confirmed that the use of DXB allows measurements of dynamics related to the functional states of the target molecules. The Dynamics of Amyloid β in early oligomerisation was measured by Diffracted X-ray Blinking, pico-meter scale method. The dynamics of Amyloid β was shrinked in more oligomerisation. The dynamics of Amyloid β (1–42) on Pd surface were recovered by 105% compared with that of normal oligomerisation. Dynamical measurement captured the recovery of Amyloid β (1–42); it is important to measure the dynamics of the oligomer.
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9
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Unksov IN, Korosec CS, Surendiran P, Verardo D, Lyttleton R, Forde NR, Linke H. Through the Eyes of Creators: Observing Artificial Molecular Motors. ACS NANOSCIENCE AU 2022; 2:140-159. [PMID: 35726277 PMCID: PMC9204826 DOI: 10.1021/acsnanoscienceau.1c00041] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022]
Abstract
![]()
Inspired by molecular
motors in biology, there has been significant
progress in building artificial molecular motors, using a number of
quite distinct approaches. As the constructs become more sophisticated,
there is also an increasing need to directly observe the motion of
artificial motors at the nanoscale and to characterize their performance.
Here, we review the most used methods that tackle those tasks. We
aim to help experimentalists with an overview of the available tools
used for different types of synthetic motors and to choose the method
most suited for the size of a motor and the desired measurements,
such as the generated force or distances in the moving system. Furthermore,
for many envisioned applications of synthetic motors, it will be a
requirement to guide and control directed motions. We therefore also
provide a perspective on how motors can be observed on structures
that allow for directional guidance, such as nanowires and microchannels.
Thus, this Review facilitates the future research on synthetic molecular
motors, where observations at a single-motor level and a detailed
characterization of motion will promote applications.
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Affiliation(s)
- Ivan N. Unksov
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Chapin S. Korosec
- Department of Physics, Simon Fraser University, V5A 1S6 Burnaby, British Columbia, Canada
| | | | - Damiano Verardo
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
- AlignedBio AB, Medicon Village, Scheeletorget 1, 223 63 Lund, Sweden
| | - Roman Lyttleton
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Nancy R. Forde
- Department of Physics, Simon Fraser University, V5A 1S6 Burnaby, British Columbia, Canada
| | - Heiner Linke
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
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10
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Real-time three-dimensional tracking of single vesicles reveals abnormal motion and pools of synaptic vesicles in neurons of Huntington's disease mice. iScience 2021; 24:103181. [PMID: 34703988 PMCID: PMC8521108 DOI: 10.1016/j.isci.2021.103181] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/30/2021] [Accepted: 09/23/2021] [Indexed: 11/23/2022] Open
Abstract
Although defective synaptic transmission was suggested to play a role in neurodegenerative diseases, the dynamics and vesicle pools of synaptic vesicles during neurodegeneration remain elusive. Here, we performed real-time three-dimensional tracking of single synaptic vesicles in cortical neurons from a mouse model of Huntington's disease (HD). Vesicles in HD neurons had a larger net displacement and radius of gyration compared with wild-type neurons. Vesicles with high release probability (Pr) were interspersed with low-Pr vesicles in HD neurons, whereas high-Pr vesicles were closer to fusion sites than low-Pr in wild-type neurons. Non-releasing vesicles in HD neurons had an abnormally high prevalence of irregular oscillatory motion. These abnormal dynamics and vesicle pools were rescued by overexpressing Rab11, and the abnormal irregular oscillatory motion was rescued by jasplakinolide. Our studies reveal the abnormal dynamics and pools of synaptic vesicles in the early stages of HD, suggesting a possible pathogenic mechanism of neurodegenerative diseases.
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11
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Unique dynamics and exocytosis properties of GABAergic synaptic vesicles revealed by three-dimensional single vesicle tracking. Proc Natl Acad Sci U S A 2021; 118:2022133118. [PMID: 33622785 DOI: 10.1073/pnas.2022133118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Maintaining the balance between neuronal excitation and inhibition is essential for proper function of the central nervous system. Inhibitory synaptic transmission plays an important role in maintaining this balance. Although inhibitory transmission has higher kinetic demands compared to excitatory transmission, its properties are poorly understood. In particular, the dynamics and exocytosis of single inhibitory vesicles have not been investigated, due largely to both technical and practical limitations. Using a combination of quantum dots (QDs) conjugated to antibodies against the luminal domain of the vesicular GABA transporter to selectively label GABAergic (i.e., predominantly inhibitory) vesicles together with dual-focus imaging optics, we tracked the real-time three-dimensional position of single GABAergic vesicles up to the moment of exocytosis (i.e., fusion). Using three-dimensional trajectories, we found that GABAergic synaptic vesicles traveled a shorter distance prior to fusion and had a shorter time to fusion compared to synaptotagmin-1 (Syt1)-labeled vesicles, which were mostly from excitatory neurons. Moreover, our analysis revealed that GABAergic synaptic vesicles move more straightly to their release sites than Syt1-labeled vesicles. Finally, we found that GABAergic vesicles have a higher prevalence of kiss-and-run fusion than Syt1-labeled vesicles. These results indicate that inhibitory synaptic vesicles have a unique set of dynamics and exocytosis properties to support rapid synaptic inhibition, thereby maintaining a tightly regulated coordination between excitation and inhibition in the central nervous system.
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12
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Danial JSH, Klenerman D. Single molecule imaging of protein aggregation in Dementia: Methods, insights and prospects. Neurobiol Dis 2021; 153:105327. [PMID: 33705938 PMCID: PMC8039184 DOI: 10.1016/j.nbd.2021.105327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/21/2021] [Accepted: 03/04/2021] [Indexed: 02/06/2023] Open
Abstract
The aggregation of misfolded proteins is a fundamental pathology in neurodegeneration which remains poorly understood due to its exceptional complexity and lack of appropriate characterization tools that can probe the role of the low concentrations of heterogeneous protein aggregates formed during the progression of the disease. In this review, we explain the principles underlying the operation of single molecule microscopy, an imaging method that can resolve molecules one-by-one, its application to imaging and characterizing individual protein aggregates in human samples and in vitro as well as the important questions in neurobiology this has answered and can answer.
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Affiliation(s)
- John S H Danial
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; UK Dementia Research Institute, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.
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13
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Label-free, mass-sensitive single-molecule imaging using interferometric scattering microscopy. Essays Biochem 2021; 65:81-91. [PMID: 33296454 DOI: 10.1042/ebc20200023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/11/2020] [Accepted: 11/16/2020] [Indexed: 12/27/2022]
Abstract
Single-molecule imaging has mostly been restricted to the use of fluorescence labelling as a contrast mechanism due to its superior ability to visualise molecules of interest on top of an overwhelming background of other molecules. Recently, interferometric scattering (iSCAT) microscopy has demonstrated the detection and imaging of single biomolecules based on light scattering without the need for fluorescent labels. Significant improvements in measurement sensitivity combined with a dependence of scattering signal on object size have led to the development of mass photometry, a technique that measures the mass of individual molecules and thereby determines mass distributions of biomolecule samples in solution. The experimental simplicity of mass photometry makes it a powerful tool to analyse biomolecular equilibria quantitatively with low sample consumption within minutes. When used for label-free imaging of reconstituted or cellular systems, the strict size-dependence of the iSCAT signal enables quantitative measurements of processes at size scales reaching from single-molecule observations during complex assembly up to mesoscopic dynamics of cellular components and extracellular protrusions. In this review, I would like to introduce the principles of this emerging imaging technology and discuss examples that show how mass-sensitive iSCAT can be used as a strong complement to other routine techniques in biochemistry.
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14
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Chang J, Baek Y, Lee I, Sekiguchi H, Ichiyanagi K, Mio K, Nozawa S, Fukaya R, Adachi SI, Kuramochi M, Sasaki YC. Diffracted X-ray blinking measurements of interleukin 15 receptors in the inner/outer membrane of living NK cells. Biochem Biophys Res Commun 2021; 556:53-58. [PMID: 33839414 DOI: 10.1016/j.bbrc.2021.03.144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 03/25/2021] [Indexed: 02/06/2023]
Abstract
Interleukin 15 receptor (IL-15R) is a transmembrane signalling protein consisting of 3 subsets: α, β (IL-15Rβ), and γ (γc). IL-2 and IL-15 share the signalling domains IL-15Rβ and γc, although they bind to intrinsic α-subsets and non-signalling domains. Additionally, IL-2 and IL-15 play different roles; therefore, there have been many observations of the dynamic behaviours of IL-15R, which are linked to physiological functions. For more practical discrimination between IL-2 and IL-15, a study was designed and carried out in which α-subsets were removed and a cytoplasmic inhibitor was applied to create a simplified environment in which secondary signalling molecules were reduced. We also applied a new measurement method, diffracted X-ray blinking (DXB), to achieve higher accuracy (<0.01 Å). The dynamics of IL-2 binding (confined motion, max range = 0.71 Å) and IL-15 binding (normal motion) in live natural killer cells were different. We also confirmed. that DXB was a suitable method to quantitatively evaluate the transmembrane protein dynamics of inner/outer live cell membranes by labeling the extracellular domain since the measurements were dependent on the cytosolic environment.
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Affiliation(s)
- Jaewon Chang
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan
| | - Yonugseok Baek
- Department of Biomedical Science, CHA University, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea; Immunotherapy Team, NBE, R&D Division, CHA BIOTECH, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea
| | - Injee Lee
- Department of Biomedical Science, CHA University, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea; Immunotherapy Team, NBE, R&D Division, CHA BIOTECH, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, 679-5198, Hyogo, Japan
| | - Kouhei Ichiyanagi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan; Division of Biophysics, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, 329-0498, Tochigi, Japan
| | - Kazuhiro Mio
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26 Aomi, 135-0064, Tokyo, Japan; AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan
| | - Shunsuke Nozawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan
| | - Ryo Fukaya
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan
| | - Shin-Ichi Adachi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan
| | - Masahiro Kuramochi
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan; AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan.
| | - Yuji C Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan; Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, 679-5198, Hyogo, Japan; AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan.
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15
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Chibac-Scutaru AL, Cojocaru C, Roman G, Samoilă P, Săcărescu G, Simionescu M, Săcărescu L. Synthesis of benzaldehyde-grafted polysilane: A highly stable and selective “turn-on” fluorescent sensor for cytosine. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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16
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Brizendine RK, Anuganti M, Cremo CR. Evidence for S2 flexibility by direct visualization of quantum dot-labeled myosin heads and rods within smooth muscle myosin filaments moving on actin in vitro. J Gen Physiol 2021; 153:211680. [PMID: 33439241 PMCID: PMC7809879 DOI: 10.1085/jgp.202012751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/18/2020] [Accepted: 12/10/2020] [Indexed: 12/21/2022] Open
Abstract
Myosins in muscle assemble into filaments by interactions between the C-terminal light meromyosin (LMM) subdomains of the coiled-coil rod domain. The two head domains are connected to LMM by the subfragment-2 (S2) subdomain of the rod. Our mixed kinetic model predicts that the flexibility and length of S2 that can be pulled away from the filament affects the maximum distance working heads can move a filament unimpeded by actin-attached heads. It also suggests that it should be possible to observe a head remain stationary relative to the filament backbone while bound to actin (dwell), followed immediately by a measurable jump upon detachment to regain the backbone trajectory. We tested these predictions by observing filaments moving along actin at varying ATP using TIRF microscopy. We simultaneously tracked two different color quantum dots (QDs), one attached to a regulatory light chain on the lever arm and the other attached to an LMM in the filament backbone. We identified events (dwells followed by jumps) by comparing the trajectories of the QDs. The average dwell times were consistent with known kinetics of the actomyosin system, and the distribution of the waiting time between observed events was consistent with a Poisson process and the expected ATPase rate. Geometric constraints suggest a maximum of ∼26 nm of S2 can be unzipped from the filament, presumably involving disruption in the coiled-coil S2, a result consistent with observations by others of S2 protruding from the filament in muscle. We propose that sufficient force is available from the working heads in the filament to overcome the stiffness imposed by filament-S2 interactions.
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Affiliation(s)
- Richard K Brizendine
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Reno, NV
| | - Murali Anuganti
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Reno, NV
| | - Christine R Cremo
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Reno, NV
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17
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Zhao T, Knappenberger KL. Advances in multi-dimensional super-resolution nonlinear optical microscopy. ADVANCES IN PHYSICS: X 2021. [DOI: 10.1080/23746149.2021.1964378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Tian Zhao
- Department Of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Kenneth L. Knappenberger
- Department Of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, United States
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18
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Kalra AP, Eakins BB, Patel SD, Ciniero G, Rezania V, Shankar K, Tuszynski JA. All Wired Up: An Exploration of the Electrical Properties of Microtubules and Tubulin. ACS NANO 2020; 14:16301-16320. [PMID: 33213135 DOI: 10.1021/acsnano.0c06945] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microtubules are hollow, cylindrical polymers of the protein α, β tubulin, that interact mechanochemically with a variety of macromolecules. Due to their mechanically robust nature, microtubules have gained attention as tracks for precisely directed transport of nanomaterials within lab-on-a-chip devices. Primarily due to the unusually negative tail-like C-termini of tubulin, recent work demonstrates that these biopolymers are also involved in a broad spectrum of intracellular electrical signaling. Microtubules and their electrostatic properties are discussed in this Review, followed by an evaluation of how these biopolymers respond mechanically to electrical stimuli, through microtubule migration, electrorotation and C-termini conformation changes. Literature focusing on how microtubules act as nanowires capable of intracellular ionic transport, charge storage, and ionic signal amplification is reviewed, illustrating how these biopolymers attenuate ionic movement in response to electrical stimuli. The Review ends with a discussion on the important questions, challenges, and future opportunities for intracellular microtubule-based electrical signaling.
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Affiliation(s)
- Aarat P Kalra
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta T6G 2M9, Canada
| | - Boden B Eakins
- Department of Electrical and Computer Engineering, University of Alberta, 9107-116 St, Edmonton, Alberta T6G 2 V4, Canada
| | - Sahil D Patel
- Department of Electrical and Computer Engineering, University of Alberta, 9107-116 St, Edmonton, Alberta T6G 2 V4, Canada
| | - Gloria Ciniero
- Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Torino 10129, Italy
| | - Vahid Rezania
- Department of Physical Sciences, MacEwan University, Edmonton, Alberta T5J 4S2, Canada
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, 9107-116 St, Edmonton, Alberta T6G 2 V4, Canada
| | - Jack A Tuszynski
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta T6G 2M9, Canada
- Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Torino 10129, Italy
- Department of Oncology, University of Alberta, Edmonton, Alberta T6G 1Z2, Canada
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19
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Fonda P, Al-Izzi SC, Giomi L, Turner MS. Measuring Gaussian Rigidity Using Curved Substrates. PHYSICAL REVIEW LETTERS 2020; 125:188002. [PMID: 33196252 DOI: 10.1103/physrevlett.125.188002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
The Gaussian (saddle splay) rigidity of fluid membranes controls their equilibrium topology but is notoriously difficult to measure. In lipid mixtures, typical of living cells, linear interfaces separate liquid ordered (LO) from liquid disordered (LD) bilayer phases at subcritical temperatures. Here, we consider such membranes supported by curved substrates that thereby control the membrane curvatures. We show how spectral analysis of the fluctuations of the LO-LD interface provides a novel way of measuring the difference in Gaussian rigidity between the two phases. We provide a number of conditions for such interface fluctuations to be both experimentally measurable and sufficiently sensitive to the value of the Gaussian rigidity, while remaining in the perturbative regime of our analysis.
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Affiliation(s)
- Piermarco Fonda
- Theory & Bio-Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - Sami C Al-Izzi
- School of Physics & EMBL-Australia node in Single Molecule Science, University of New South Wales, 2052 Sydney, Australia
- Department of Mathematics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Institut Curie, PSL Research University, CNRS, Physical Chemistry Curie, F-75005, Paris, France
| | - Luca Giomi
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - Matthew S Turner
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Centre for Complexity Science, University of Warwick, Coventry CV4 7AL, United Kingdom
- Department of Chemical Engineering, University of Kyoto, Kyoto 615-8510, Japan
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20
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Martin-Fernandez ML. A brief history of the octopus imaging facility to celebrate its 10th anniversary. J Microsc 2020; 281:3-15. [PMID: 33111321 DOI: 10.1111/jmi.12974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 11/27/2022]
Abstract
Octopus (Optics Clustered to OutPut Unique Solutions) celebrated in June 2020 its 10th birthday. Based at Harwell, near Oxford, Octopus is an open access, peer reviewed, national imaging facility that offers successful U.K. applicants supported access to single molecule imaging, confocal microscopy, several flavours of superresolution imaging, light sheet microscopy, optical trapping and cryoscanning electron microscopy. Managed by a multidisciplinary team, Octopus has so far assisted >100 groups of U.K. and international researchers. Cross-fertilisation across fields proved to be a strong propeller of success underpinned by combining access to top-end instrumentation with a strong programme of imaging hardware and software developments. How Octopus was born, and highlights of the multidisciplinary output produced during its 10-year journey are reviewed below, with the aim of celebrating a myriad of collaborations with the U.K. scientific community, and reflecting on their scientific and societal impact.
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Affiliation(s)
- M L Martin-Fernandez
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford, U.K
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21
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Möckl L, Moerner WE. Super-resolution Microscopy with Single Molecules in Biology and Beyond-Essentials, Current Trends, and Future Challenges. J Am Chem Soc 2020; 142:17828-17844. [PMID: 33034452 PMCID: PMC7582613 DOI: 10.1021/jacs.0c08178] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Indexed: 12/31/2022]
Abstract
Single-molecule super-resolution microscopy has developed from a specialized technique into one of the most versatile and powerful imaging methods of the nanoscale over the past two decades. In this perspective, we provide a brief overview of the historical development of the field, the fundamental concepts, the methodology required to obtain maximum quantitative information, and the current state of the art. Then, we will discuss emerging perspectives and areas where innovation and further improvement are needed. Despite the tremendous progress, the full potential of single-molecule super-resolution microscopy is yet to be realized, which will be enabled by the research ahead of us.
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Affiliation(s)
- Leonhard Möckl
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - W. E. Moerner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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22
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Wallum A, Nguyen HA, Gruebele M. Excited-State Imaging of Single Particles on the Subnanometer Scale. Annu Rev Phys Chem 2020; 71:415-433. [DOI: 10.1146/annurev-physchem-071119-040108] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
At the intersection of spectroscopy and microscopy lie techniques that are capable of providing subnanometer imaging of excited states of individual molecules or nanoparticles. Such approaches are particularly important for imaging macromolecules or nanoparticles large enough to have a high probability of containing a defect. These inevitable defects often control properties and function despite an otherwise ideal structure. We discuss real-space imaging techniques such as using scanning tunneling microscopy tips to enhance optical measurements and electron energy-loss spectroscopy in a scanning transmission electron microscope, which is based on focused electron beams to obtain high-resolution spatial information on excited states. The outlook for these methods is bright, as they will provide critical information for the characterization and improvement of energy-switching, electron-switching, and energy-harvesting materials.
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Affiliation(s)
- Alison Wallum
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Huy A. Nguyen
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Martin Gruebele
- Department of Chemistry and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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23
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Oswald F, Prevo B, Acar S, Peterman EJG. Interplay between Ciliary Ultrastructure and IFT-Train Dynamics Revealed by Single-Molecule Super-resolution Imaging. Cell Rep 2020; 25:224-235. [PMID: 30282031 DOI: 10.1016/j.celrep.2018.09.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 08/08/2018] [Accepted: 09/07/2018] [Indexed: 01/10/2023] Open
Abstract
Cilia are built and maintained by intraflagellar transport (IFT), driving IFT trains back and forth along the ciliary axoneme. How IFT brings about the intricate ciliary structure and how this structure affects IFT are not well understood. We identify, using single-molecule super-resolution imaging of IFT components in living C. elegans, ciliary subdomains, enabling correlation of IFT-train dynamics to ciliary ultra-structure. In the transition zone, IFT dynamics are impaired, resulting in frequent pauses. At the ciliary base and tip, IFT trains show intriguing turnaround dynamics. Surprisingly, deletion of IFT motor kinesin-II not only affects IFT-train dynamics but also alters ciliary structure. Super-resolution imaging in these mutant animals suggests that the arrangement of IFT trains with respect to the axonemal microtubules is different than in wild-type animals. Our results reveal a complex, mutual interplay between ciliary ultrastructure and IFT-train dynamics, highlighting the importance of physical cues in the control of IFT dynamics.
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Affiliation(s)
- Felix Oswald
- Department of Physics and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, 1081HV, the Netherlands
| | - Bram Prevo
- Department of Physics and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, 1081HV, the Netherlands
| | - Seyda Acar
- Department of Physics and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, 1081HV, the Netherlands
| | - Erwin J G Peterman
- Department of Physics and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, 1081HV, the Netherlands.
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24
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Sellers JR, Takagi Y. How Myosin 5 Walks Deduced from Single-Molecule Biophysical Approaches. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1239:153-181. [PMID: 32451859 DOI: 10.1007/978-3-030-38062-5_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Myosin 5a is a two-headed myosin that functions as a cargo transporter in cells. To accomplish this task it has evolved several unique structural and kinetic features that allow it to move processively as a single molecule along actin filaments. A plethora of biophysical techniques have been used to elucidate the detailed mechanism of its movement along actin filaments in vitro. This chapter describes how this mechanism was deduced.
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Affiliation(s)
- James R Sellers
- Laboratory of Molecular Physiology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Yasuharu Takagi
- Laboratory of Molecular Physiology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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25
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Li Y, Zhao L, Yao Y, Guo X. Single-Molecule Nanotechnologies: An Evolution in Biological Dynamics Detection. ACS APPLIED BIO MATERIALS 2019; 3:68-85. [DOI: 10.1021/acsabm.9b00840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu Li
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Lihua Zhao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Yuan Yao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Xuefeng Guo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
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26
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Tjioe M, Shukla S, Vaidya R, Troitskaia A, Bookwalter CS, Trybus KM, Chemla YR, Selvin PR. Multiple kinesins induce tension for smooth cargo transport. eLife 2019; 8:50974. [PMID: 31670658 PMCID: PMC6904222 DOI: 10.7554/elife.50974] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 10/31/2019] [Indexed: 12/17/2022] Open
Abstract
How cargoes move within a crowded cell—over long distances and at speeds nearly the same as when moving on unimpeded pathway—has long been mysterious. Through an in vitro force-gliding assay, which involves measuring nanometer displacement and piconewtons of force, we show that multiple mammalian kinesin-1 (from 2 to 8) communicate in a team by inducing tension (up to 4 pN) on the cargo. Kinesins adopt two distinct states, with one-third slowing down the microtubule and two-thirds speeding it up. Resisting kinesins tend to come off more rapidly than, and speed up when pulled by driving kinesins, implying an asymmetric tug-of-war. Furthermore, kinesins dynamically interact to overcome roadblocks, occasionally combining their forces. Consequently, multiple kinesins acting as a team may play a significant role in facilitating smooth cargo motion in a dense environment. This is one of few cases in which single molecule behavior can be connected to ensemble behavior of multiple motors. The inside of a cell is a crowded space, full of proteins and other molecules. Yet, the molecular motors that transport some of those molecules within the cell move at the same speed as they would in pure water – about one micrometer per second. How the molecular motors could achieve such speeds in crowded cells was unclear. Nevertheless, Tjioe et al. suspected that the answer might be related to how multiple motors work together. Molecular motors move by walking along filaments inside the cell and pulling their cargo from one location to another. Other molecules that bind to the filaments should, in theory, act like “roadblocks” and impede the movement of the cargo. Tjioe et al. studied a motor protein called kinesin, which walks on filaments called microtubules. But instead of looking at these motors moving along microtubules inside a cell, Tjioe et al. used a simpler system where the cell was eliminated, and all parts were purified. Specifically, Tjioe et al. tethered purified motors to a piece of glass and then observed them under an extremely accurate microscope as they moved free-floating, fluorescently labelled microtubules. The microtubules, in this scenario, were acting like cargoes, where many kinesins could bind. Each kinesin motor also had a small chemical tag that could emit light. By following the movement of the lights, it was possible to calculate what each kinesin was doing and how the cargo moved. When more than one kinesin molecule was acting, the tension and speed of one kinesin affected the movement of the others. In any group of kinesins, about two-thirds of kinesin pulled the cargo, and unexpectedly, about one-third tended to resist and slow the cargo. These latter kinesins were moved along with the group without actually driving the cargo. These resisting kinesins did come off more rapidly than the driving kinesins, meaning the cargo should be able to quickly bypass roadblocks. This would help to keep the whole group travelling in the right direction at a steady pace.
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Affiliation(s)
- Marco Tjioe
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Saurabh Shukla
- Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.,Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Rohit Vaidya
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Alice Troitskaia
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Carol S Bookwalter
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Kathleen M Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Yann R Chemla
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Paul R Selvin
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
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27
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Ye Z, Wei L, Geng X, Wang X, Li Z, Xiao L. Mitochondrion-Specific Blinking Fluorescent Bioprobe for Nanoscopic Monitoring of Mitophagy. ACS NANO 2019; 13:11593-11602. [PMID: 31592641 DOI: 10.1021/acsnano.9b05354] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Dynamic changes of mitochondrial morphology play an important role in cellular metabolism. Real-time monitoring mitochondrial ultrastructural dynamics at nanometer-scale resolution is crucially desired for further understanding of the mitochondria-based cellular function. In this work, we introduce a fluorescent carbon dot, which can selectively target mitochondria in live cells (named as MitoCD). MitoCD can effectively accumulate in mitochondria regardless of the decrease or vanishing of mitochondrial membrane potential (MMP), enabling the exploration of MMP-independent mitochondrial process. Moreover, the MitoCD is a thiol-based reaction-free probe that target mitochondria without consuming the thiol groups from mitochondrial proteins. Additionally, the MitoCD possesses good photophysical properties under physiological conditions, such as burst-like blinking, high photon counts, and low "on"/"off" ratio, which are specifically suitable for localization-based nanoscopic imaging. According to the optical microscopic imaging results, dynamical fission and fusion processes from mitochondria have been observed in live cells. During mitophagy, it is found that reticular formation of the mitochondria gradually collapsed, and then a portion of mitochondria split and vanished. Owing to the attractive biological and special photophysical properties, this probe displays promising application in a variety of super-resolution based biological studies and will provide deep insight in mitochondrial metabolism.
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Affiliation(s)
- Zhongju Ye
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Lin Wei
- College of Chemistry and Chemical Engineering , Hunan Normal University , Changsha 410081 , China
| | - Xin Geng
- College of Chemistry and Molecular Engineering , Zhengzhou University , Zhengzhou 450001 , China
| | - Xin Wang
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Zhaohui Li
- College of Chemistry and Molecular Engineering , Zhengzhou University , Zhengzhou 450001 , China
| | - Lehui Xiao
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry , Nankai University , Tianjin 300071 , China
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28
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Mickolajczyk KJ, Cook ASI, Jevtha JP, Fricks J, Hancock WO. Insights into Kinesin-1 Stepping from Simulations and Tracking of Gold Nanoparticle-Labeled Motors. Biophys J 2019; 117:331-345. [PMID: 31301807 DOI: 10.1016/j.bpj.2019.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 02/02/2023] Open
Abstract
High-resolution tracking of gold nanoparticle-labeled proteins has emerged as a powerful technique for measuring the structural kinetics of processive enzymes and other biomacromolecules. These techniques use point spread function (PSF) fitting methods borrowed from single-molecule fluorescence imaging to determine molecular positions below the diffraction limit. However, compared to fluorescence, gold nanoparticle tracking experiments are performed at significantly higher frame rates and utilize much larger probes. In the current work, we use Brownian dynamics simulations of nanoparticle-labeled proteins to investigate the regimes in which the fundamental assumptions of PSF fitting hold and where they begin to break down. We find that because gold nanoparticles undergo tethered diffusion around their anchor point, PSF fitting cannot be extended to arbitrarily fast frame rates. Instead, camera exposure times that allow the nanoparticle to fully populate its stationary positional distribution achieve a spatial averaging that increases fitting precision. We furthermore find that changes in the rotational freedom of the tagged protein can lead to artifactual translations in the fitted particle position. Finally, we apply these lessons to dissect a standing controversy in the kinesin field over the structure of a dimer in the ATP waiting state. Combining new experiments with simulations, we determine that the rear kinesin head in the ATP waiting state is unbound but not displaced from its previous microtubule binding site and that apparent differences in separately published reports were simply due to differences in the gold nanoparticle attachment position. Our results highlight the importance of gold conjugation decisions and imaging parameters to high-resolution tracking results and will serve as a useful guide for the design of future gold nanoparticle tracking experiments.
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Affiliation(s)
- Keith J Mickolajczyk
- Department of Biomedical Engineering; Intercollege Graduate Degree Program in Bioengineering
| | - Annan S I Cook
- Department of Biomedical Engineering; Department of Physics, Pennsylvania State University, University Park, Pennsylvania
| | | | - John Fricks
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona
| | - William O Hancock
- Department of Biomedical Engineering; Intercollege Graduate Degree Program in Bioengineering.
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29
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Abstract
Interferometric scattering microscopy (iSCAT) is an extremely sensitive imaging method based on the efficient detection of light scattered by nanoscopic objects. The ability to, at least in principle, maintain high imaging contrast independent of the exposure time or the scattering cross section of the object allows for unique applications in single-particle tracking, label-free imaging of nanoscopic (dis)assembly, and quantitative single-molecule characterization. We illustrate these capabilities in areas as diverse as mechanistic studies of motor protein function, viral capsid assembly, and single-molecule mass measurement in solution. We anticipate that iSCAT will become a widely used approach to unravel previously hidden details of biomolecular dynamics and interactions.
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Affiliation(s)
- Gavin Young
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom; ,
| | - Philipp Kukura
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom; ,
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Gicking AM, Wang P, Liu C, Mickolajczyk KJ, Guo L, Hancock WO, Qiu W. The Orphan Kinesin PAKRP2 Achieves Processive Motility via a Noncanonical Stepping Mechanism. Biophys J 2019; 116:1270-1281. [PMID: 30902363 DOI: 10.1016/j.bpj.2019.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 02/07/2019] [Accepted: 02/19/2019] [Indexed: 12/27/2022] Open
Abstract
Phragmoplast-associated kinesin-related protein 2 (PAKRP2) is an orphan kinesin in Arabidopsis thaliana that is thought to transport vesicles along phragmoplast microtubules for cell plate formation. Here, using single-molecule fluorescence microscopy, we show that PAKRP2 is the first orphan kinesin to exhibit processive plus-end-directed motility on single microtubules as individual homodimers. Our results show that PAKRP2 processivity is achieved despite having an exceptionally long (32 residues) neck linker. Furthermore, using high-resolution nanoparticle tracking, we find that PAKRP2 steps via a hand-over-hand mechanism that includes frequent side steps, a prolonged diffusional search of the tethered head, and tight coupling of the ATP hydrolysis cycle to the forward-stepping cycle. Interestingly, truncating the PAKRP2 neck linker to 14 residues decreases the run length of PAKRP2; thus, the long neck linker enhances the processive behavior. Based on the canonical model of kinesin stepping, such a long neck linker is expected to decrease the processivity and disrupt the coupling of ATP hydrolysis to forward stepping. Therefore, we conclude that PAKRP2 employs a noncanonical strategy for processive motility, wherein a long neck linker is coupled with a slow ATP hydrolysis rate to allow for an extended diffusional search during each step without sacrificing processivity or efficiency.
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Affiliation(s)
| | - Pan Wang
- Department of Physics, Oregon State University, Corvallis, Oregon; School of Physics and Electronics, Henan University, Kaifeng, Henan, China
| | - Chun Liu
- Pearl River Fisheries Research Institute, Guangzhou, China
| | - Keith J Mickolajczyk
- Department of Biomedical Engineering, Penn State University, University Park, Pennsylvania; Intercollege Graduate Degree Program in Bioengineering, Penn State University, University Park, Pennsylvania
| | - Lijun Guo
- School of Physics and Electronics, Henan University, Kaifeng, Henan, China
| | - William O Hancock
- Department of Biomedical Engineering, Penn State University, University Park, Pennsylvania; Intercollege Graduate Degree Program in Bioengineering, Penn State University, University Park, Pennsylvania
| | - Weihong Qiu
- Department of Physics, Oregon State University, Corvallis, Oregon; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon.
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Clarke DT, Martin-Fernandez ML. A Brief History of Single-Particle Tracking of the Epidermal Growth Factor Receptor. Methods Protoc 2019; 2:mps2010012. [PMID: 31164594 PMCID: PMC6481046 DOI: 10.3390/mps2010012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/21/2019] [Accepted: 01/21/2019] [Indexed: 12/15/2022] Open
Abstract
Single-particle tracking (SPT) has been used and developed over the last 25 years as a method to investigate molecular dynamics, structure, interactions, and function in the cellular context. SPT is able to show how fast and how far individual molecules move, identify different dynamic populations, measure the duration and strength of intermolecular interactions, and map out structures on the nanoscale in cells. In combination with other techniques such as macromolecular crystallography and molecular dynamics simulation, it allows us to build models of complex structures, and develop and test hypotheses of how these complexes perform their biological roles in health as well as in disease states. Here, we use the example of the epidermal growth factor receptor (EGFR), which has been studied extensively by SPT, demonstrating how the method has been used to increase our understanding of the receptor’s organization and function, including its interaction with the plasma membrane, its activation, clustering, and oligomerization, and the role of other receptors and endocytosis. The examples shown demonstrate how SPT might be employed in the investigation of other biomolecules and systems.
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Affiliation(s)
- David T Clarke
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
| | - Marisa L Martin-Fernandez
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
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Fujimoto K, Morita Y, Iino R, Tomishige M, Shintaku H, Kotera H, Yokokawa R. Simultaneous Observation of Kinesin-Driven Microtubule Motility and Binding of Adenosine Triphosphate Using Linear Zero-Mode Waveguides. ACS NANO 2018; 12:11975-11985. [PMID: 30418736 DOI: 10.1021/acsnano.8b03803] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Single-molecule fluorescence observation of adenosine triphosphate (ATP) is a powerful tool to elucidate the chemomechanical coupling of ATP with a motor protein. However, in total internal reflection fluorescence microscopy (TIRFM), available ATP concentration is much lower than that in the in vivo environment. To achieve single-molecule observation with a high signal-to-noise ratio, zero-mode waveguides (ZMWs) are utilized even at high fluorescent molecule concentrations in the micromolar range. Despite the advantages of ZMWs, the use of cytoskeletal filaments for single-molecule observation has not been reported because of difficulties in immobilization of cytoskeletal filaments in the cylindrical aperture of ZMWs. Here, we propose linear ZMWs (LZMWs) to visualize enzymatic reactions on cytoskeletal filaments, specifically kinesin-driven microtubule motility accompanied by ATP binding/unbinding. Finite element method simulation revealed excitation light confinement in a 100 nm wide slit of LZMWs. Single-molecule observation was then demonstrated with up to 1 μM labeled ATP, which was 10-fold higher than that available in TIRFM. Direct observation of binding/unbinding of ATP to kinesins that propel microtubules enabled us to find that a significant fraction of ATP molecules bound to kinesins were dissociated without hydrolysis. This highlights the advantages of LZMWs for single-molecule observation of proteins that interact with cytoskeletal filaments such as microtubules, actin filaments, or intermediate filaments.
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Affiliation(s)
- Kazuya Fujimoto
- Department of Micro Engineering , Kyoto University , Kyoto 615-8540 , Japan
| | - Yuki Morita
- Department of Micro Engineering , Kyoto University , Kyoto 615-8540 , Japan
| | - Ryota Iino
- Institute for Molecular Science , National Institutes of Natural Sciences , Okazaki , Aichi 444-8787 , Japan
| | - Michio Tomishige
- College of Science and Engineering , Aoyama Gakuin University , Kanagawa 252-5258 , Japan
| | - Hirofumi Shintaku
- Department of Micro Engineering , Kyoto University , Kyoto 615-8540 , Japan
| | - Hidetoshi Kotera
- Department of Micro Engineering , Kyoto University , Kyoto 615-8540 , Japan
| | - Ryuji Yokokawa
- Department of Micro Engineering , Kyoto University , Kyoto 615-8540 , Japan
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Ray S, Chauvier A, Walter NG. Kinetics coming into focus: single-molecule microscopy of riboswitch dynamics. RNA Biol 2018; 16:1077-1085. [PMID: 30328748 DOI: 10.1080/15476286.2018.1536594] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Riboswitches are dynamic RNA motifs that are mostly embedded in the 5'-untranslated regions of bacterial mRNAs, where they regulate gene expression transcriptionally or translationally by undergoing conformational changes upon binding of a small metabolite or ion. Due to the small size of typical ligands, relatively little free energy is available from ligand binding to overcome the often high energetic barrier of reshaping RNA structure. Instead, most riboswitches appear to take advantage of the directional and hierarchical folding of RNA by employing the ligand as a structural 'linchpin' to adjust the kinetic partitioning between alternate folds. In this model, even small, local structural and kinetic effects of ligand binding can cascade into global RNA conformational changes affecting gene expression. Single-molecule (SM) microscopy tools are uniquely suited to study such kinetically controlled RNA folding since they avoid the ensemble averaging of bulk techniques that loses sight of unsynchronized, transient, and/or multi-state kinetic behavior. This review summarizes how SM methods have begun to unravel riboswitch-mediated gene regulation.
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Affiliation(s)
- Sujay Ray
- a Single Molecule Analysis Group, Department of Chemistry, University of Michigan , Ann Arbor , MI , USA
| | - Adrien Chauvier
- a Single Molecule Analysis Group, Department of Chemistry, University of Michigan , Ann Arbor , MI , USA
| | - Nils G Walter
- a Single Molecule Analysis Group, Department of Chemistry, University of Michigan , Ann Arbor , MI , USA
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Mojard Kalkhoran S, Chow SHJ, Walia JS, Gershome C, Saraev N, Kim B, Poburko D. VNUT and VMAT2 segregate within sympathetic varicosities and localize near preferred Cav2 isoforms in the rat tail artery. Am J Physiol Heart Circ Physiol 2018; 316:H89-H105. [PMID: 30311774 DOI: 10.1152/ajpheart.00560.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
ATP and norepinephrine (NE) are coreleased from peripheral sympathetic nerve terminals. Whether they are stored in the same vesicles has been debated for decades. Preferential dependence of NE or ATP release on Ca2+ influx through specific voltage-gated Ca2+ channel (Cav2) isoforms suggests that NE and ATP are stored in separate vesicle pools, but simultaneous imaging of NE and ATP containing vesicles within single varicosities has not been reported. We conducted an immunohistochemical study of vesicular monoamine transporter 2 (VMAT2/SLC18A2) and vesicular nucleotide translocase (VNUT/SLC17A9) as markers of vesicles containing NE and ATP in sympathetic nerves of the rat tail artery. A large fraction of varicosities exhibited neighboring, rather than overlapping, VNUT and VMAT2 fluorescent puncta. VMAT2, but not VNUT, colocalized with synaptotagmin 1. Cav2.1, Cav2.2, and Cav2.3 are expressed in nerves in the tunica adventitia. VMAT2 preferentially localized adjacent to Cav2.2 and Cav2.3 rather than Cav2.1. VNUT preferentially localized adjacent to Cav2.3 > Cav2.2 >> Cav2.1. With the use of wire myography, inhibition of field-stimulated vasoconstriction with the Cav2.3 blocker SNX-482 (0.25 µM) mimicked the effects of the P2X inhibitor suramin (100 µM) rather than the α-adrenergic inhibitor phentolamine (10 µM). Variable sensitivity to SNX-482 and suramin between animals closely correlated with Cav2.3 staining. We concluded that a majority of ATP and NE stores localize to separate vesicle pools that use different synaptotagmin isoforms and that localize near different Cav2 isoforms to mediate vesicle release. Cav2.3 appears to play a previously unrecognized role in mediating ATP release in the rat tail artery. NEW & NOTEWORTHY Immunofluorescence imaging of vesicular nucleotide translocase and vesicular monoamine transporter 2 in rat tail arteries revealed that ATP and norepinephrine, classical cotransmitters, localize to well-segregated vesicle pools. Furthermore, vesicular nucleotide translocase and vesicular monoamine transporter 2 exhibit preferential localization with specific Cav2 isoforms. These novel observations address long-standing debates regarding the mechanism(s) of sympathetic neurotransmitter corelease.
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Affiliation(s)
- Somayeh Mojard Kalkhoran
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada.,Centre for Cell Biology, Development and Disease, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Sarah Heather Jane Chow
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Jagdeep Singh Walia
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Cynthia Gershome
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Nickolas Saraev
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - BaRun Kim
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Damon Poburko
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada.,Centre for Cell Biology, Development and Disease, Simon Fraser University , Burnaby, British Columbia , Canada
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Jeon Y, Choi YH, Jang Y, Yu J, Goo J, Lee G, Jeong YK, Lee SH, Kim IS, Kim JS, Jeong C, Lee S, Bae S. Direct observation of DNA target searching and cleavage by CRISPR-Cas12a. Nat Commun 2018; 9:2777. [PMID: 30018371 PMCID: PMC6050341 DOI: 10.1038/s41467-018-05245-x] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/20/2018] [Indexed: 12/24/2022] Open
Abstract
Cas12a (also called Cpf1) is a representative type V-A CRISPR effector RNA-guided DNA endonuclease, which provides an alternative to type II CRISPR-Cas9 for genome editing. Previous studies have revealed that Cas12a has unique features distinct from Cas9, but the detailed mechanisms of target searching and DNA cleavage by Cas12a are still unclear. Here, we directly observe this entire process by using single-molecule fluorescence assays to study Cas12a from Acidaminococcus sp. (AsCas12a). We determine that AsCas12a ribonucleoproteins search for their on-target site by a one-dimensional diffusion along elongated DNA molecules and induce cleavage in the two DNA strands in a well-defined order, beginning with the non-target strand. Furthermore, the protospacer-adjacent motif (PAM) for AsCas12a makes only a limited contribution of DNA unwinding during R-loop formation and shows a negligible role in the process of DNA cleavage, in contrast to the Cas9 PAM.
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Affiliation(s)
- Yongmoon Jeon
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - You Hee Choi
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Yunsu Jang
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Jihyeon Yu
- Department of Chemistry, Hanyang University, Seoul, 04763, South Korea
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, 04763, South Korea
| | - Jiyoung Goo
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KHU-KIST Department of Converging Science and Technology, Kyunghee University, Seoul, 02447, South Korea
| | - Gyejun Lee
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KHU-KIST Department of Converging Science and Technology, Kyunghee University, Seoul, 02447, South Korea
| | - You Kyeong Jeong
- Department of Chemistry, Hanyang University, Seoul, 04763, South Korea
| | - Seung Hwan Lee
- Center for Genome Engineering, Institute for Basic Science, Seoul, 08826, South Korea
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungcheongbuk-do, 28116, South Korea
| | - In-San Kim
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Jin-Soo Kim
- Center for Genome Engineering, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Cherlhyun Jeong
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul, 02792, South Korea.
- KHU-KIST Department of Converging Science and Technology, Kyunghee University, Seoul, 02447, South Korea.
| | - Sanghwa Lee
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea.
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea.
| | - Sangsu Bae
- Department of Chemistry, Hanyang University, Seoul, 04763, South Korea.
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, 04763, South Korea.
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36
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Lee S, Kim H, Higuchi H. Numerical method for vesicle movement analysis in a complex cytoskeleton network. OPTICS EXPRESS 2018; 26:16236-16249. [PMID: 30119458 DOI: 10.1364/oe.26.016236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 05/28/2018] [Indexed: 06/08/2023]
Abstract
The detection of the precise movement of a vesicle during transport in a live cell provides key information for the intracellular delivery process. Here we report a novel numerical method for analyzing three-dimensional vesicle movement. Since the vesicle moves along a linear cytoskeleton during the active transport, our method first detects the orientation and position of the cytoskeleton as a linear section based on angle correlation and linear regression, after noise reduction. Then, the precise vesicle movement is calculated using vector analysis, in terms of rotation angle and translational displacement. Using this method, various vesicle trajectories obtained via high spatiotemporal resolution microscopy can be understood..
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Li Y, Schroeder JW, Simmons LA, Biteen JS. Visualizing bacterial DNA replication and repair with molecular resolution. Curr Opin Microbiol 2018; 43:38-45. [PMID: 29197672 PMCID: PMC5984126 DOI: 10.1016/j.mib.2017.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/28/2017] [Accepted: 11/06/2017] [Indexed: 10/18/2022]
Abstract
Although DNA replication and repair in bacteria have been extensively studied for many decades, in recent years the development of single-molecule microscopy has provided a new perspective on these fundamental processes. Because single-molecule imaging super-resolves the nanometer-scale dynamics of molecules, and because single-molecule imaging is sensitive to heterogeneities within a sample, this nanoscopic microscopy technique measures the motions, localizations, and interactions of proteins in real time without averaging ensemble observations, both in vitro and in vivo. In this Review, we provide an overview of several recent single-molecule fluorescence microscopy studies on DNA replication and repair. These experiments have shown that, in both Escherichia coli and Bacillus subtilis the DNA replication proteins are highly dynamic. In particular, even highly processive replicative DNA polymerases exchange to and from the replication fork on the scale of a few seconds. Furthermore, single-molecule investigations of the DNA mismatch repair (MMR) pathway have measured the complex interactions between MMR proteins, replication proteins, and DNA. Single-molecule imaging will continue to improve our understanding of fundamental processes in bacteria including DNA replication and repair.
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Affiliation(s)
- Yilai Li
- University of Michigan, Ann Arbor, MI 48109, United States
| | - Jeremy W Schroeder
- University of Michigan, Ann Arbor, MI 48109, United States; University of Wisconsin, Madison, WI 53706, United States
| | - Lyle A Simmons
- University of Michigan, Ann Arbor, MI 48109, United States
| | - Julie S Biteen
- University of Michigan, Ann Arbor, MI 48109, United States.
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Rogacki MK, Golfetto O, Tobin SJ, Li T, Biswas S, Jorand R, Zhang H, Radoi V, Ming Y, Svenningsson P, Ganjali D, Wakefield DL, Sideris A, Small AR, Terenius L, Jovanović‐Talisman T, Vukojević V. Dynamic lateral organization of opioid receptors (kappa, mu wt and mu N40D ) in the plasma membrane at the nanoscale level. Traffic 2018; 19:690-709. [PMID: 29808515 PMCID: PMC6120469 DOI: 10.1111/tra.12582] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/06/2018] [Accepted: 05/18/2018] [Indexed: 02/06/2023]
Abstract
Opioid receptors are important pharmacological targets for the management of numerous medical conditions (eg, severe pain), but they are also the gateway to the development of deleterious side effects (eg, opiate addiction). Opioid receptor signaling cascades are well characterized. However, quantitative information regarding their lateral dynamics and nanoscale organization in the plasma membrane remains limited. Since these dynamic properties are important determinants of receptor function, it is crucial to define them. Herein, the nanoscale lateral dynamics and spatial organization of kappa opioid receptor (KOP), wild type mu opioid receptor (MOPwt ), and its naturally occurring isoform (MOPN40D ) were quantitatively characterized using fluorescence correlation spectroscopy and photoactivated localization microscopy. Obtained results, supported by ensemble-averaged Monte Carlo simulations, indicate that these opioid receptors dynamically partition into different domains. In particular, significant exclusion from GM1 ganglioside-enriched domains and partial association with cholesterol-enriched domains was observed. Nanodomain size, receptor population density and the fraction of receptors residing outside of nanodomains were receptor-specific. KOP-containing domains were the largest and most densely populated, with the smallest fraction of molecules residing outside of nanodomains. The opposite was true for MOPN40D . Moreover, cholesterol depletion dynamically regulated the partitioning of KOP and MOPwt , whereas this effect was not observed for MOPN40D .
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Affiliation(s)
- Maciej K. Rogacki
- Department of Clinical NeuroscienceCenter for Molecular Medicine, Karolinska InstituteStockholmSweden
| | - Ottavia Golfetto
- Department of Molecular Medicine, Beckman Research Institute, City of HopeDuarteCalifornia
| | - Steven J. Tobin
- Department of Molecular Medicine, Beckman Research Institute, City of HopeDuarteCalifornia
| | - Tianyi Li
- Department of Clinical NeuroscienceCenter for Molecular Medicine, Karolinska InstituteStockholmSweden
| | - Sunetra Biswas
- Department of Molecular Medicine, Beckman Research Institute, City of HopeDuarteCalifornia
| | - Raphael Jorand
- Department of Molecular Medicine, Beckman Research Institute, City of HopeDuarteCalifornia
| | - Huiying Zhang
- Department of Molecular Medicine, Beckman Research Institute, City of HopeDuarteCalifornia
| | - Vlad Radoi
- Department of Clinical NeuroscienceCenter for Molecular Medicine, Karolinska InstituteStockholmSweden
| | - Yu Ming
- Department of Clinical NeuroscienceCenter for Molecular Medicine, Karolinska InstituteStockholmSweden
| | - Per Svenningsson
- Department of Clinical NeuroscienceCenter for Molecular Medicine, Karolinska InstituteStockholmSweden
| | - Daniel Ganjali
- Department of Mechanical and Aerospace EngineeringThe Henry Samueli School of Engineering, University of CaliforniaIrvineCalifornia
| | - Devin L. Wakefield
- Department of Molecular Medicine, Beckman Research Institute, City of HopeDuarteCalifornia
| | - Athanasios Sideris
- Department of Mechanical and Aerospace EngineeringThe Henry Samueli School of Engineering, University of CaliforniaIrvineCalifornia
| | - Alexander R. Small
- Department of Physics and AstronomyCalifornia State Polytechnic UniversityPomonaCalifornia
| | - Lars Terenius
- Department of Clinical NeuroscienceCenter for Molecular Medicine, Karolinska InstituteStockholmSweden
- Department of Molecular and Cellular NeurosciencesThe Scripps Research InstituteLa JollaCalifornia
| | | | - Vladana Vukojević
- Department of Clinical NeuroscienceCenter for Molecular Medicine, Karolinska InstituteStockholmSweden
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40
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Goh Y, Song YH, Lee G, Bae H, Mahata MK, Lee KT. Cellular uptake efficiency of nanoparticles investigated by three-dimensional imaging. Phys Chem Chem Phys 2018; 20:11359-11368. [PMID: 29644351 DOI: 10.1039/c8cp00493e] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Understanding the interaction of nanoparticles with living cells on the basis of cellular uptake efficiency is a fundamental requisite in biomedical research. Cellular internalization of nanoparticles takes place by mechanisms like ATP hydrolysis-driven endocytosis that deliver nanoparticles to the cytoplasm, organelles and nuclei. Despite its importance in nanomedicine, this uptake procedure is not understood in-depth because of the complexity of the biochemical mechanisms and the lack of available experimental methods for quantitative analysis. The only breakthrough is likely to be the development of imaging techniques that can visualize, monitor and even count the number of nanoparticles inside the cell. To this end, we report here a new, fast and background-free three-dimensional (3-D) imaging technique with quantitative evaluation of the uptake efficiency for NaYF4:Yb3+,Er3+/NaYF4 core/shell upconversion nanoparticles (UCNPs) functionalized with different chemical and biological groups. Furthermore, the multiple 3-D trajectories of the UCNPs have been analyzed to investigate the cellular dynamics. This study reveals the nuclear uptake of UCNPs to be dependent on the specific chemical groups conjugated to the UCNPs. The developed 3-D imaging technique is of great significance for exploring complex biological systems.
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Affiliation(s)
- Yeongchang Goh
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, Korea.
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Parveen N, Borrenberghs D, Rocha S, Hendrix J. Single Viruses on the Fluorescence Microscope: Imaging Molecular Mobility, Interactions and Structure Sheds New Light on Viral Replication. Viruses 2018; 10:E250. [PMID: 29748498 PMCID: PMC5977243 DOI: 10.3390/v10050250] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/24/2018] [Accepted: 05/04/2018] [Indexed: 12/13/2022] Open
Abstract
Viruses are simple agents exhibiting complex reproductive mechanisms. Decades of research have provided crucial basic insights, antiviral medication and moderately successful gene therapy trials. The most infectious viral particle is, however, not always the most abundant one in a population, questioning the utility of classic ensemble-averaging virology. Indeed, viral replication is often not particularly efficient, prone to errors or containing parallel routes. Here, we review different single-molecule sensitive fluorescence methods that we employ routinely to investigate viruses. We provide a brief overview of the microscopy hardware needed and discuss the different methods and their application. In particular, we review how we applied (i) single-molecule Förster resonance energy transfer (smFRET) to probe the subviral human immunodeficiency virus (HIV-1) integrase (IN) quaternary structure; (ii) single particle tracking to study interactions of the simian virus 40 with membranes; (iii) 3D confocal microscopy and smFRET to quantify the HIV-1 pre-integration complex content and quaternary structure; (iv) image correlation spectroscopy to quantify the cytosolic HIV-1 Gag assembly, and finally; (v) super-resolution microscopy to characterize the interaction of HIV-1 with tetherin during assembly. We hope this review is an incentive for setting up and applying similar single-virus imaging studies in daily virology practice.
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Affiliation(s)
- Nagma Parveen
- Laboratory for Photochemistry and Spectroscopy, Molecular Imaging and Photonics Division, Chemistry Department, KU Leuven, B-3001 Leuven, Belgium.
| | - Doortje Borrenberghs
- Laboratory for Photochemistry and Spectroscopy, Molecular Imaging and Photonics Division, Chemistry Department, KU Leuven, B-3001 Leuven, Belgium.
| | - Susana Rocha
- Laboratory for Photochemistry and Spectroscopy, Molecular Imaging and Photonics Division, Chemistry Department, KU Leuven, B-3001 Leuven, Belgium.
| | - Jelle Hendrix
- Laboratory for Photochemistry and Spectroscopy, Molecular Imaging and Photonics Division, Chemistry Department, KU Leuven, B-3001 Leuven, Belgium.
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute (BIOMED), Hasselt University, B-3590 Diepenbeek, Belgium.
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Vangindertael J, Camacho R, Sempels W, Mizuno H, Dedecker P, Janssen KPF. An introduction to optical super-resolution microscopy for the adventurous biologist. Methods Appl Fluoresc 2018; 6:022003. [DOI: 10.1088/2050-6120/aaae0c] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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van den Wildenberg SMJL, Prevo B, Peterman EJG. A Brief Introduction to Single-Molecule Fluorescence Methods. Methods Mol Biol 2018; 1665:93-113. [PMID: 28940065 DOI: 10.1007/978-1-4939-7271-5_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
One of the more popular single-molecule approaches in biological science is single-molecule fluorescence microscopy, which will be the subject of the following section of this volume. Fluorescence methods provide the sensitivity required to study biology on the single-molecule level, but they also allow access to useful measurable parameters on time and length scales relevant for the biomolecular world. Before several detailed experimental approaches will be addressed, we will first give a general overview of single-molecule fluorescence microscopy. We start with discussing the phenomenon of fluorescence in general and the history of single-molecule fluorescence microscopy. Next, we will review fluorescent probes in more detail and the equipment required to visualize them on the single-molecule level. We will end with a description of parameters measurable with such approaches, ranging from protein counting and tracking, single-molecule localization super-resolution microscopy, to distance measurements with Förster Resonance Energy Transfer and orientation measurements with fluorescence polarization.
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Affiliation(s)
- Siet M J L van den Wildenberg
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
- Équipe de Volcanologie, Observatoire de Physique de Globe, Clermant-Ferrand, France
| | - Bram Prevo
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- LaserLaB and Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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Pandey V, Gupta S, Elangovan R. Compact 3D printed module for fluorescence and label-free imaging using evanescent excitation. Methods Appl Fluoresc 2017; 6:015007. [PMID: 29076809 DOI: 10.1088/2050-6120/aa967a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Total internal reflection fluorescence (TIRF) microscopy is widely used for selective excitation and high-resolution imaging of fluorophores, and more recently label-free nanosized objects, with high vertical confinement near a liquid-solid interface. Traditionally, high numerical aperture objectives (>1.4) are used to simultaneously generate evanescent waves and collect fluorescence emission signals which limits their use to small area imaging (<0.1 mm2). Objective-based TIRFs are also expensive as they require dichroic mirrors and efficient notch filters to prevent specular reflection within the objective lenses. We have developed a compact 3D module called cTIRF that can generate evanescent waves in microscope glass slides via a planar waveguide illumination. The module can be attached as a fixture to any existing optical microscope, converting it into a TIRF and enabling high signal-to-noise ratio (SNR) fluorescence imaging using any magnification objective. As the incidence optics is perpendicular to the detector, label-free evanescent scattering-based imaging of submicron objects can also be performed without using emission filters. SNR is significantly enhanced in this case as compared to cTIRF alone, as seen through our model experiments performed on latex beads and mammalian cells. Extreme flexibility and the low cost of our approach makes it scalable for limited resource settings.
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Affiliation(s)
- Vikas Pandey
- Department of Chemical Engineering, Indian Institute of Technology, Delhi, 110016, India
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45
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Pasulka AL, Thamatrakoln K, Kopf SH, Guan Y, Poulos B, Moradian A, Sweredoski MJ, Hess S, Sullivan MB, Bidle KD, Orphan VJ. Interrogating marine virus-host interactions and elemental transfer with BONCAT and nanoSIMS-based methods. Environ Microbiol 2017; 20:671-692. [DOI: 10.1111/1462-2920.13996] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/10/2017] [Accepted: 11/12/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Alexis L. Pasulka
- Division of Geological and Planetary Sciences; California Institute of Technology; CA USA
| | | | - Sebastian H. Kopf
- Department of Geological Sciences, University of Colorado Boulder; CO USA
| | - Yunbin Guan
- Division of Geological and Planetary Sciences; California Institute of Technology; CA USA
| | - Bonnie Poulos
- Department of Ecology and Evolutionary Biology, University of Arizona; AZ USA
| | - Annie Moradian
- Proteome Exploration Laboratory, California Institute of Technology; CA USA
| | | | - Sonja Hess
- Proteome Exploration Laboratory, California Institute of Technology; CA USA
| | | | - Kay D. Bidle
- Department of Marine and Coastal Studies; Rutgers University; NJ USA
| | - Victoria J. Orphan
- Division of Geological and Planetary Sciences; California Institute of Technology; CA USA
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Chen K, Gu Y, Sun W, Bin Dong, Wang G, Fan X, Xia T, Fang N. Characteristic rotational behaviors of rod-shaped cargo revealed by automated five-dimensional single particle tracking. Nat Commun 2017; 8:887. [PMID: 29026088 PMCID: PMC5638882 DOI: 10.1038/s41467-017-01001-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 08/09/2017] [Indexed: 01/03/2023] Open
Abstract
We report an automated single particle tracking technique for tracking the x, y, z coordinates, azimuthal and elevation angles of anisotropic plasmonic gold nanorod probes in live cells. These five spatial coordinates are collectively referred to as 5D. This method overcomes a long-standing challenge in distinguishing rotational motions from translational motions in the z-axis in differential interference contrast microscopy to result in full disclosure of nanoscale motions with high accuracy. Transferrin-coated endocytic gold nanorod cargoes initially undergo active rotational diffusion and display characteristic rotational motions on the membrane. Then as the cargoes being enclosed in clathrin-coated pits, they slow down the active rotation and experience a quiet period before they restore active rotational diffusion after fission and eventually being transported away from the original entry spots. Finally, the 3D trajectories and the accompanying rotational motions of the cargoes are resolved accurately to render the intracellular transport process in live cells.Distinguishing rotational motions from translational motions in the z-axis has been a long-standing challenge. Here the authors develop a five-dimensional single particle tracking method to detect rotational behaviors of nanocargos during clathrin-mediated endocytosis and intracellular transport.
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Affiliation(s)
- Kuangcai Chen
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | - Yan Gu
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
- The Bristol-Myers Squibb Company, Devens, MA, 01434, USA
| | - Wei Sun
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
- Corning Inc., Painted Post, NY, 14870, USA
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | - Gufeng Wang
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
- Department of Chemistry, North Carolina State University, Rayleigh, NC, 27695, USA
| | - Xinxin Fan
- Department of Electronics and Information Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Tian Xia
- Department of Electronics and Information Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA.
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47
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Zhao F, Chen K, Dong B, Yang K, Gu Y, Fang N. Localization accuracy of gold nanoparticles in single particle orientation and rotational tracking. OPTICS EXPRESS 2017; 25:9860-9871. [PMID: 28468365 PMCID: PMC5462070 DOI: 10.1364/oe.25.009860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/13/2017] [Accepted: 04/14/2017] [Indexed: 06/07/2023]
Abstract
The Single Particle Orientation and Rotational Tracking (SPORT) technique, which utilizes anisotropic plasmonic gold nanorods and differential interference contrast (DIC) microscopy, has shown potential as an effective alternative to fluorescence-based techniques to decipher rotational motions on the cellular and molecular levels. However, localizing gold nanorods from their DIC images with high accuracy and precision is more challenging than the procedures applied in fluorescence or scattering microscopy techniques due to the asymmetric DIC point spread function with bright and dark parts superimposed over a grey background. In this paper, localization accuracy and inherited uncertainties from unique DIC image patterns are elucidated with the assistance of computer simulation. These discussions provide guidance for researchers to properly evaluate their data and avoid making claims beyond the technical limits. The understanding of the intrinsic localization errors and the principle of DIC microscopy leads us to propose a new localization strategy that utilizes the experimentally-measured shear distance of the DIC microscope to improve the localization accuracy.
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Affiliation(s)
- Fei Zhao
- Department of Chemistry, Georgia State University, Atlanta, Georgia, 30303,
USA
| | - Kuangcai Chen
- Department of Chemistry, Georgia State University, Atlanta, Georgia, 30303,
USA
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, Georgia, 30303,
USA
| | - Kai Yang
- Center for Soft Condensed Matter Physics & Interdisciplinary Research, Soochow University, Suzhou, Jiangsu, China, 215006,
USA
| | - Yan Gu
- The Bristol-Myers Squibb Company, Devens, Massachusetts, USA 01434,
USA
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, Georgia, 30303,
USA
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Colomb W, Czerski J, Sau JD, Sarkar SK. Estimation of microscope drift using fluorescent nanodiamonds as fiducial markers. J Microsc 2017; 266:298-306. [PMID: 28328030 DOI: 10.1111/jmi.12539] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 01/16/2017] [Accepted: 01/25/2017] [Indexed: 01/10/2023]
Abstract
Fiducial markers are used to correct the microscope drift and should be photostable, be usable at multiple wavelengths and be compatible for multimodal imaging. Fiducial markers such as beads, gold nanoparticles, microfabricated patterns and organic fluorophores lack one or more of these criteria. Moreover, the localization accuracy and drift correction can be degraded by other fluorophores, instrument noise and artefacts due to image processing and tracking algorithms. Estimating mechanical drift by assuming Gaussian distributed noise is not suitable under these circumstances. Here we present a method that uses fluorescent nanodiamonds as fiducial markers and uses an improved maximum likelihood algorithm to estimate the drift with both accuracy and precision within the range 1.55-5.75 nm.
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Affiliation(s)
- W Colomb
- Department of Physics, Colorado School of Mines, Golden, Colorado, U.S.A
| | - J Czerski
- Department of Physics, Colorado School of Mines, Golden, Colorado, U.S.A
| | - J D Sau
- Department of Physics, University of Maryland, College Park, MD, U.S.A
| | - S K Sarkar
- Department of Physics, Colorado School of Mines, Golden, Colorado, U.S.A
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Abstract
Super-resolution fluorescence imaging by photoactivation or photoswitching of single fluorophores and position determination (single-molecule localization microscopy, SMLM) provides microscopic images with subdiffraction spatial resolution. This technology has enabled new insights into how proteins are organized in a cellular context, with a spatial resolution approaching virtually the molecular level. A unique strength of SMLM is that it delivers molecule-resolved information, along with super-resolved images of cellular structures. This allows quantitative access to cellular structures, for example, how proteins are distributed and organized and how they interact with other biomolecules. Ultimately, it is even possible to determine protein numbers in cells and the number of subunits in a protein complex. SMLM thus has the potential to pave the way toward a better understanding of how cells function at the molecular level. In this review, we describe how SMLM has contributed new knowledge in eukaryotic biology, and we specifically focus on quantitative biological data extracted from SMLM images.
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Affiliation(s)
- Markus Sauer
- Department of Biotechnology & Biophysics, Julius-Maximilian-University of Würzburg , 97074 Würzburg, Germany
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt , 60438 Frankfurt, Germany
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Uçar MC, Lipowsky R. Tug-of-war between two elastically coupled molecular motors: a case study on force generation and force balance. SOFT MATTER 2017; 13:328-344. [PMID: 27910992 DOI: 10.1039/c6sm01853j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Intracellular transport is performed by molecular motors that pull cargos along cytoskeletal filaments. Many cellular cargos are observed to move bidirectionally, with fast transport in both directions. This behaviour can be understood as a stochastic tug-of-war between two teams of antagonistic motors. The first theoretical model for such a tug-of-war, the Müller-Klumpp-Lipowsky (MKL) model, was based on two simplifying assumptions: (i) both motor teams move with the same velocity in the direction of the stronger team, and (ii) this velocity matching and the associated force balance arise immediately after the rebinding of an unbound motor to the filament. In this study, we extend the MKL model by including an elastic coupling between the antagonistic motors, and by allowing the motors to perform discrete motor steps. Each motor step changes the elastic interaction forces experienced by the motors. In order to elucidate the basic concepts of force balance and force fluctuations, we focus on the simplest case of two antagonistic motors, one kinesin against one dynein. We calculate the probability distribution for the spatial separation of the motors and the dependence of this distribution on the motors' unbinding rate. We also compute the probability distribution for the elastic interaction forces experienced by the motors, which determines the average elastic force 〈F〉 and the standard deviation of the force fluctuations around this average value. The average force 〈F〉 is found to decrease monotonically with increasing unbinding rate ε0. The behaviour of the MKL model is recovered in the limit of small ε0. In the opposite limit of large ε0, 〈F〉 is found to decay to zero as 1/ε0. Finally, we study the limiting case with ε0 = 0 for which we determine both the force statistics and the time needed to attain the steady state. Our theoretical predictions are accessible to experimental studies of in vitro systems consisting of two antagonistic motors attached to a synthetic scaffold or crosslinked via DNA hybridization.
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Affiliation(s)
- Mehmet Can Uçar
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
| | - Reinhard Lipowsky
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany.
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