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Lahlou A, Tehrani HS, Coghill I, Shpinov Y, Mandal M, Plamont MA, Aujard I, Niu Y, Nedbal L, Lazár D, Mahou P, Supatto W, Beaurepaire E, Eisenmann I, Desprat N, Croquette V, Jeanneret R, Le Saux T, Jullien L. Fluorescence to measure light intensity. Nat Methods 2023; 20:1930-1938. [PMID: 37996751 PMCID: PMC10703675 DOI: 10.1038/s41592-023-02063-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 10/02/2023] [Indexed: 11/25/2023]
Abstract
Despite the need for quantitative measurements of light intensity across many scientific disciplines, existing technologies for measuring light dose at the sample of a fluorescence microscope cannot simultaneously retrieve light intensity along with spatial distribution over a wide range of wavelengths and intensities. To address this limitation, we developed two rapid and straightforward protocols that use organic dyes and fluorescent proteins as actinometers. The first protocol relies on molecular systems whose fluorescence intensity decays and/or rises in a monoexponential fashion when constant light is applied. The second protocol relies on a broad-absorbing photochemically inert fluorophore to back-calculate the light intensity from one wavelength to another. As a demonstration of their use, the protocols are applied to quantitatively characterize the spatial distribution of light of various fluorescence imaging systems, and to calibrate illumination of commercially available instruments and light sources.
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Affiliation(s)
- Aliénor Lahlou
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France.
- Sony Computer Science Laboratories, Paris, France.
| | - Hessam Sepasi Tehrani
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France
| | - Ian Coghill
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France
| | - Yuriy Shpinov
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France
| | - Mrinal Mandal
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France
| | - Marie-Aude Plamont
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France
| | - Isabelle Aujard
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France
| | - Yuxi Niu
- Institute of Bio- and Geosciences/Plant Sciences, Forschungszentrum Jülich, Jülich, Germany
| | - Ladislav Nedbal
- Institute of Bio- and Geosciences/Plant Sciences, Forschungszentrum Jülich, Jülich, Germany
- Department of Biophysics, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Dusan Lazár
- Department of Biophysics, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Pierre Mahou
- Laboratory for Optics and Biosciences, Ecole Polytechnique, CNRS, INSERM, IP Paris, Palaiseau, France
| | - Willy Supatto
- Laboratory for Optics and Biosciences, Ecole Polytechnique, CNRS, INSERM, IP Paris, Palaiseau, France
| | - Emmanuel Beaurepaire
- Laboratory for Optics and Biosciences, Ecole Polytechnique, CNRS, INSERM, IP Paris, Palaiseau, France
| | - Isabelle Eisenmann
- Laboratory of Physics of the École Normale Supérieure, University of PSL, CNRS, Sorbonne University, University of Paris City, Paris, France
- Institute of Biology of ENS (IBENS), École Normale Supérieure, CNRS, INSERM, University of PSL, Paris, France
| | - Nicolas Desprat
- Laboratory of Physics of the École Normale Supérieure, University of PSL, CNRS, Sorbonne University, University of Paris City, Paris, France
- Institute of Biology of ENS (IBENS), École Normale Supérieure, CNRS, INSERM, University of PSL, Paris, France
| | - Vincent Croquette
- Laboratory of Physics of the École Normale Supérieure, University of PSL, CNRS, Sorbonne University, University of Paris City, Paris, France
- Institute of Biology of ENS (IBENS), École Normale Supérieure, CNRS, INSERM, University of PSL, Paris, France
| | - Raphaël Jeanneret
- Laboratory of Physics of the École Normale Supérieure, University of PSL, CNRS, Sorbonne University, University of Paris City, Paris, France
- Institute of Biology of ENS (IBENS), École Normale Supérieure, CNRS, INSERM, University of PSL, Paris, France
| | - Thomas Le Saux
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France.
| | - Ludovic Jullien
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne University, CNRS, Paris, France.
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2
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Anaya EU, Amin AE, Wester MJ, Danielson ME, Michel KS, Neumann AK. Dectin-1 multimerization and signaling depends on fungal β-glucan structure and exposure. Biophys J 2023; 122:3749-3767. [PMID: 37515324 PMCID: PMC10541497 DOI: 10.1016/j.bpj.2023.07.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 06/30/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023] Open
Abstract
Dectin-1A is a C-type lectin innate immunoreceptor that recognizes β-(1,3;1,6)-glucan, a structural component of Candida species cell walls. β-Glucans can adopt solution structures ranging from random coil to insoluble fiber due to tertiary (helical) and quaternary structure. Fungal β-glucans of medium and high molecular weight are highly structured, but low molecular weight glucan is much less structured. Despite similar affinity for Dectin-1, the ability of glucans to induce Dectin-1A-mediated signaling correlates with degree of structure. Glucan denaturation experiments showed that glucan structure determines agonistic potential, but not receptor binding affinity. We explored the impact of glucan structure on molecular aggregation of Dectin-1A. Stimulation with glucan signaling decreased Dectin-1A diffusion coefficient. Fluorescence measurements provided direct evidence of ligation-induced Dectin-1A aggregation, which positively correlated with increasing glucan structure content. In contrast, Dectin-1A is predominantly in a low aggregation state in resting cells. Molecular aggregates formed during interaction with highly structured, agonistic glucans did not exceed relatively small (<15 nm) clusters of a few engaged receptors. Finally, we observed increased molecular aggregation of Dectin-1A at fungal particle contact sites in a manner that positively correlated with the degree of exposed glucan on the particle surface. These results indicate that Dectin-1A senses the solution conformation of β-glucans through their varying ability to drive receptor dimer/oligomer formation and activation of membrane proximal signaling events.
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Affiliation(s)
- Eduardo U Anaya
- Department of Pathology, University of New Mexico, School of Medicine, Albuquerque, New Mexico
| | - Akram Etemadi Amin
- Department of Pathology, University of New Mexico, School of Medicine, Albuquerque, New Mexico; Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico
| | - Michael J Wester
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico
| | | | | | - Aaron K Neumann
- Department of Pathology, University of New Mexico, School of Medicine, Albuquerque, New Mexico.
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3
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Sankaran J, Wohland T. Current capabilities and future perspectives of FCS: super-resolution microscopy, machine learning, and in vivo applications. Commun Biol 2023; 6:699. [PMID: 37419967 PMCID: PMC10328937 DOI: 10.1038/s42003-023-05069-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 06/23/2023] [Indexed: 07/09/2023] Open
Abstract
Fluorescence correlation spectroscopy (FCS) is a single molecule sensitive tool for the quantitative measurement of biomolecular dynamics and interactions. Improvements in biology, computation, and detection technology enable real-time FCS experiments with multiplexed detection even in vivo. These new imaging modalities of FCS generate data at the rate of hundreds of MB/s requiring efficient data processing tools to extract information. Here, we briefly review FCS's capabilities and limitations before discussing recent directions that address these limitations with a focus on imaging modalities of FCS, their combinations with super-resolution microscopy, new evaluation strategies, especially machine learning, and applications in vivo.
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Affiliation(s)
- Jagadish Sankaran
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, 138632, Singapore.
| | - Thorsten Wohland
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore.
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4
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Guthmann M, Qian C, Gialdini I, Nakatani T, Ettinger A, Schauer T, Kukhtevich I, Schneider R, Lamb DC, Burton A, Torres-Padilla ME. A change in biophysical properties accompanies heterochromatin formation in mouse embryos. Genes Dev 2023; 37:336-350. [PMID: 37072228 PMCID: PMC10153458 DOI: 10.1101/gad.350353.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 03/31/2023] [Indexed: 04/20/2023]
Abstract
The majority of our genome is composed of repeated DNA sequences that assemble into heterochromatin, a highly compacted structure that constrains their mutational potential. How heterochromatin forms during development and how its structure is maintained are not fully understood. Here, we show that mouse heterochromatin phase-separates after fertilization, during the earliest stages of mammalian embryogenesis. Using high-resolution quantitative imaging and molecular biology approaches, we show that pericentromeric heterochromatin displays properties consistent with a liquid-like state at the two-cell stage, which change at the four-cell stage, when chromocenters mature and heterochromatin becomes silent. Disrupting the condensates results in altered transcript levels of pericentromeric heterochromatin, suggesting a functional role for phase separation in heterochromatin function. Thus, our work shows that mouse heterochromatin forms membrane-less compartments with biophysical properties that change during development and provides new insights into the self-organization of chromatin domains during mammalian embryogenesis.
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Affiliation(s)
- Manuel Guthmann
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Chen Qian
- Department of Chemistry, Center for NanoScience (CeNS), Ludwig Maximilians-Universität München, 81377 München, Germany
| | - Irene Gialdini
- Department of Chemistry, Center for NanoScience (CeNS), Ludwig Maximilians-Universität München, 81377 München, Germany
| | - Tsunetoshi Nakatani
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Andreas Ettinger
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Tamas Schauer
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Igor Kukhtevich
- Institute of Functional Epigenetics (IFE), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - Robert Schneider
- Institute of Functional Epigenetics (IFE), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - Don C Lamb
- Department of Chemistry, Center for NanoScience (CeNS), Ludwig Maximilians-Universität München, 81377 München, Germany
| | - Adam Burton
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Maria-Elena Torres-Padilla
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany;
- Faculty of Biology, Ludwig-Maximilians Universität, München, 82152 Planegg, Germany
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5
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Díaz M, Malacrida L. Advanced Fluorescence Microscopy Methods to Study Dynamics of Fluorescent Proteins In Vivo. Methods Mol Biol 2023; 2564:53-74. [PMID: 36107337 DOI: 10.1007/978-1-0716-2667-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Fluorescent proteins are standard tools for addressing biological questions in a cell biology laboratory. The genetic tagging of protein of interest with fluorescent proteins opens the opportunity to follow them in vivo and to understand their interactions and dynamics. In addition, the latest advances in optical microscopy image acquisition and processing allow us to study many cellular processes in vivo. Techniques such as fluorescence lifetime microscopy and hyperspectral imaging provide valuable tools for understanding fluorescent protein interactions and their photophysics. Finally, fluorescence fluctuation analysis opens the possibility to address questions of molecular diffusion, protein-protein interactions, and oligomerization, among others, yielding quantitative information on the subject of study. This chapter will cover some of the more important advances in cutting-edge technologies and methods that, combined with fluorescent proteins, open new frontiers for biological studies.
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Affiliation(s)
- Marcela Díaz
- Advanced Bioimaging Unit, Institut Pasteur of Montevideo & Universidad de la República, Montevideo, Uruguay
| | - Leonel Malacrida
- Advanced Bioimaging Unit, Institut Pasteur of Montevideo & Universidad de la República, Montevideo, Uruguay.
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
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6
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The BrightEyes-TTM as an open-source time-tagging module for democratising single-photon microscopy. Nat Commun 2022; 13:7406. [PMID: 36456575 PMCID: PMC9715684 DOI: 10.1038/s41467-022-35064-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
Fluorescence laser-scanning microscopy (LSM) is experiencing a revolution thanks to new single-photon (SP) array detectors, which give access to an entirely new set of single-photon information. Together with the blooming of new SP LSM techniques and the development of tailored SP array detectors, there is a growing need for (i) DAQ systems capable of handling the high-throughput and high-resolution photon information generated by these detectors, and (ii) incorporating these DAQ protocols in existing fluorescence LSMs. We developed an open-source, low-cost, multi-channel time-tagging module (TTM) based on a field-programmable gate array that can tag in parallel multiple single-photon events, with 30 ps precision, and multiple synchronisation events, with 4 ns precision. We use the TTM to demonstrate live-cell super-resolved fluorescence lifetime image scanning microscopy and fluorescence lifetime fluctuation spectroscopy. We expect that our BrightEyes-TTM will support the microscopy community in spreading SP-LSM in many life science laboratories.
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7
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Hetero-pentamerization determines mobility and conductance of Glycine receptor α3 splice variants. Cell Mol Life Sci 2022; 79:540. [PMID: 36197517 PMCID: PMC9534812 DOI: 10.1007/s00018-022-04506-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/21/2022] [Accepted: 07/23/2022] [Indexed: 11/05/2022]
Abstract
Glycine receptors (GlyRs) are ligand-gated pentameric chloride channels in the central nervous system. GlyR-α3 is a possible target for chronic pain treatment and temporal lobe epilepsy. Alternative splicing into K or L variants determines the subcellular fate and function of GlyR-α3, yet it remains to be shown whether its different splice variants can functionally co-assemble, and what the properties of such heteropentamers would be. Here, we subjected GlyR-α3 to a combined fluorescence microscopy and electrophysiology analysis. We employ masked Pearson’s and dual-color spatiotemporal correlation analysis to prove that GlyR-α3 splice variants heteropentamerize, adopting the mobility of the K variant. Fluorescence-based single-subunit counting experiments revealed a variable and concentration ratio dependent hetero-stoichiometry. Via cell-attached single-channel electrophysiology we show that heteropentamers exhibit currents in between those of K and L variants. Our data are compatible with a model where α3 heteropentamerization fine-tunes mobility and activity of GlyR-α3 channels, which is important to understand and tackle α3 related diseases.
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8
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Münch JL, Paul F, Schmauder R, Benndorf K. Bayesian inference of kinetic schemes for ion channels by Kalman filtering. eLife 2022; 11:e62714. [PMID: 35506659 PMCID: PMC9342998 DOI: 10.7554/elife.62714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 04/22/2022] [Indexed: 11/16/2022] Open
Abstract
Inferring adequate kinetic schemes for ion channel gating from ensemble currents is a daunting task due to limited information in the data. We address this problem by using a parallelized Bayesian filter to specify hidden Markov models for current and fluorescence data. We demonstrate the flexibility of this algorithm by including different noise distributions. Our generalized Kalman filter outperforms both a classical Kalman filter and a rate equation approach when applied to patch-clamp data exhibiting realistic open-channel noise. The derived generalization also enables inclusion of orthogonal fluorescence data, making unidentifiable parameters identifiable and increasing the accuracy of the parameter estimates by an order of magnitude. By using Bayesian highest credibility volumes, we found that our approach, in contrast to the rate equation approach, yields a realistic uncertainty quantification. Furthermore, the Bayesian filter delivers negligibly biased estimates for a wider range of data quality. For some data sets, it identifies more parameters than the rate equation approach. These results also demonstrate the power of assessing the validity of algorithms by Bayesian credibility volumes in general. Finally, we show that our Bayesian filter is more robust against errors induced by either analog filtering before analog-to-digital conversion or by limited time resolution of fluorescence data than a rate equation approach.
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Affiliation(s)
- Jan L Münch
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich Schiller University JenaJenaGermany
| | - Fabian Paul
- Department of Biochemistry and Molecular Biology, University of ChicagoChicagoUnited States
| | - Ralf Schmauder
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich Schiller University JenaJenaGermany
| | - Klaus Benndorf
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich Schiller University JenaJenaGermany
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9
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Morana O, Nieto‐Garai JA, Björkholm P, Bernardino de la Serna J, Terrones O, Arboleya A, Ciceri D, Rojo‐Bartolomé I, Blouin CM, Lamaze C, Lorizate M, Contreras F. Identification of a New Cholesterol-Binding Site within the IFN-γ Receptor that is Required for Signal Transduction. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105170. [PMID: 35166455 PMCID: PMC9008429 DOI: 10.1002/advs.202105170] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/26/2022] [Indexed: 05/05/2023]
Abstract
The cytokine interferon-gamma (IFN-γ) is a master regulator of innate and adaptive immunity involved in a broad array of human diseases that range from atherosclerosis to cancer. IFN-γ exerts it signaling action by binding to a specific cell surface receptor, the IFN-γ receptor (IFN-γR), whose activation critically depends on its partition into lipid nanodomains. However, little is known about the impact of specific lipids on IFN-γR signal transduction activity. Here, a new conserved cholesterol (chol) binding motif localized within its single transmembrane domain is identified. Through direct binding, chol drives the partition of IFN-γR2 chains into plasma membrane lipid nanodomains, orchestrating IFN-γR oligomerization and transmembrane signaling. Bioinformatics studies show that the signature sequence stands for a conserved chol-binding motif presented in many mammalian membrane proteins. The discovery of chol as the molecular switch governing IFN-γR transmembrane signaling represents a significant advance for understanding the mechanism of lipid selectivity by membrane proteins, but also for figuring out the role of lipids in modulating cell surface receptor function. Finally, this study suggests that inhibition of the chol-IFNγR2 interaction may represent a potential therapeutic strategy for various IFN-γ-dependent diseases.
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Affiliation(s)
- Ornella Morana
- Instituto Biofisika (UPV/EHU, CSIC)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Fundación Biofísica Bizkaia/Biofisika Bizkaia Fundazioa (FBB)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
| | - Jon Ander Nieto‐Garai
- Instituto Biofisika (UPV/EHU, CSIC)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Fundación Biofísica Bizkaia/Biofisika Bizkaia Fundazioa (FBB)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
| | - Patrik Björkholm
- Center for Biomembrane ResearchDepartment of Biochemistry and BiophysicsStockholm UniversityStockholmSE‐106 91Sweden
- Science for Life LaboratoryStockholm UniversitySolnaSE‐171 21Sweden
| | - Jorge Bernardino de la Serna
- National Heart and Lung InstituteFaculty of MedicineImperial College LondonSouth KensingtonSir Alexander Fleming BuildingLondonSW7 2AZUK
- Central Laser FacilityRutherford Appleton LaboratoryMRC‐Research Complex at HarwellScience and Technology Facilities CouncilHarwellOX11 0QXUK
- NIHR Imperial Biomedical Research CentreLondonSW7 2AZUK
| | - Oihana Terrones
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
| | - Aroa Arboleya
- Instituto Biofisika (UPV/EHU, CSIC)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Fundación Biofísica Bizkaia/Biofisika Bizkaia Fundazioa (FBB)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
| | - Dalila Ciceri
- Instituto Biofisika (UPV/EHU, CSIC)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Fundación Biofísica Bizkaia/Biofisika Bizkaia Fundazioa (FBB)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
| | - Iratxe Rojo‐Bartolomé
- Instituto Biofisika (UPV/EHU, CSIC)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Fundación Biofísica Bizkaia/Biofisika Bizkaia Fundazioa (FBB)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
| | - Cédric M. Blouin
- Institut Curie ‐ Centre de RecherchePSL Research UniversityMembrane Mechanics and Dynamics of Intracellular Signaling LaboratoryParis75248France
- Institut National de la Santé et de la Recherche Médicale (INSERM)ParisU1143France
- Centre National de la Recherche Scientifique (CNRS)UMR 3666Paris75248France
| | - Christophe Lamaze
- Institut Curie ‐ Centre de RecherchePSL Research UniversityMembrane Mechanics and Dynamics of Intracellular Signaling LaboratoryParis75248France
- Institut National de la Santé et de la Recherche Médicale (INSERM)ParisU1143France
- Centre National de la Recherche Scientifique (CNRS)UMR 3666Paris75248France
| | - Maier Lorizate
- Instituto Biofisika (UPV/EHU, CSIC)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
| | - Francesc‐Xabier Contreras
- Instituto Biofisika (UPV/EHU, CSIC)University of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- Department of Biochemistry and Molecular BiologyFaculty of Science and TechnologyUniversity of the Basque Country (UPV/EHU)Barrio Sarriena s/nLeioaE‐48940Spain
- IKERBASQUEBasque Foundation for ScienceBilbao48011Spain
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10
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Laurence MJ, Carpenter TS, Laurence TA, Coleman MA, Shelby M, Liu C. Biophysical Characterization of Membrane Proteins Embedded in Nanodiscs Using Fluorescence Correlation Spectroscopy. MEMBRANES 2022; 12:membranes12040392. [PMID: 35448362 PMCID: PMC9028781 DOI: 10.3390/membranes12040392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 02/04/2023]
Abstract
Proteins embedded in biological membranes perform essential functions in all organisms, serving as receptors, transporters, channels, cell adhesion molecules, and other supporting cellular roles. These membrane proteins comprise ~30% of all human proteins and are the targets of ~60% of FDA-approved drugs, yet their extensive characterization using established biochemical and biophysical methods has continued to be elusive due to challenges associated with the purification of these insoluble proteins. In response, the development of nanodisc techniques, such as nanolipoprotein particles (NLPs) and styrene maleic acid polymers (SMALPs), allowed membrane proteins to be expressed and isolated in solution as part of lipid bilayer rafts with defined, consistent nanometer sizes and compositions, thus enabling solution-based measurements. Fluorescence correlation spectroscopy (FCS) is a relatively simple yet powerful optical microscopy-based technique that yields quantitative biophysical information, such as diffusion kinetics and concentrations, about individual or interacting species in solution. Here, we first summarize current nanodisc techniques and FCS fundamentals. We then provide a focused review of studies that employed FCS in combination with nanodisc technology to investigate a handful of membrane proteins, including bacteriorhodopsin, bacterial division protein ZipA, bacterial membrane insertases SecYEG and YidC, Yersinia pestis type III secretion protein YopB, yeast cell wall stress sensor Wsc1, epidermal growth factor receptor (EGFR), ABC transporters, and several G protein-coupled receptors (GPCRs).
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Affiliation(s)
- Matthew J. Laurence
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
| | - Timothy S. Carpenter
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
| | - Ted A. Laurence
- Materials Science Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA;
| | - Matthew A. Coleman
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
- Department of Radiation Oncology, University of California Davis, Sacramento, CA 95616, USA
| | - Megan Shelby
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
- Correspondence: (M.S.); (C.L.)
| | - Chao Liu
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA; (M.J.L.); (T.S.C.); (M.A.C.)
- Correspondence: (M.S.); (C.L.)
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11
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The microprotein Nrs1 rewires the G1/S transcriptional machinery during nitrogen limitation in budding yeast. PLoS Biol 2022; 20:e3001548. [PMID: 35239649 PMCID: PMC8893695 DOI: 10.1371/journal.pbio.3001548] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 01/19/2022] [Indexed: 12/01/2022] Open
Abstract
Commitment to cell division at the end of G1 phase, termed Start in the budding yeast Saccharomyces cerevisiae, is strongly influenced by nutrient availability. To identify new dominant activators of Start that might operate under different nutrient conditions, we screened a genome-wide ORF overexpression library for genes that bypass a Start arrest caused by absence of the G1 cyclin Cln3 and the transcriptional activator Bck2. We recovered a hypothetical gene YLR053c, renamed NRS1 for Nitrogen-Responsive Start regulator 1, which encodes a poorly characterized 108 amino acid microprotein. Endogenous Nrs1 was nuclear-localized, restricted to poor nitrogen conditions, induced upon TORC1 inhibition, and cell cycle-regulated with a peak at Start. NRS1 interacted genetically with SWI4 and SWI6, which encode subunits of the main G1/S transcription factor complex SBF. Correspondingly, Nrs1 physically interacted with Swi4 and Swi6 and was localized to G1/S promoter DNA. Nrs1 exhibited inherent transactivation activity, and fusion of Nrs1 to the SBF inhibitor Whi5 was sufficient to suppress other Start defects. Nrs1 appears to be a recently evolved microprotein that rewires the G1/S transcriptional machinery under poor nitrogen conditions. Commitment to cell division at the end of G1 phase in the budding yeast Saccharomyces cerevisiae is strongly influenced by nutrient availability. This study identifies a micro-protein that promotes G1/S transcription activation and cell cycle entry in yeast under nitrogen-limited conditions.
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12
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Makaremi S, Moran-Mirabal J. Measuring the Lateral Diffusion of Plasma Membrane Receptors Using Raster Image Correlation Spectroscopy. Methods Mol Biol 2022; 2440:289-303. [PMID: 35218546 DOI: 10.1007/978-1-0716-2051-9_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Raster image correlation spectroscopy (RICS) enables detecting and quantifying diffusion in live cells using standard commercial laser scanning confocal microscopes. Here, we describe a protocol based on RICS for measuring the lateral diffusion of two immunoreceptors within the plasma membrane of the macrophage cell line RAW 264.7. The sample images and measurements presented in this chapter were obtained from RICS analysis of Toll-like receptor 2 (TLR2) and cluster of differentiation 14 (CD14), which are transmembrane and membrane-anchored receptors, respectively. A step-by-step guideline is provided to acquire raster-scanned images and to extract the diffusion coefficients using RICS analysis.
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Affiliation(s)
- Sara Makaremi
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
| | - Jose Moran-Mirabal
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada.
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON, Canada.
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13
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Van den Broeck L, Gobble M, Sozzani R. Quantifying Intercellular Movement and Protein Stoichiometry for Computational Modeling. Methods Mol Biol 2022; 2457:367-382. [PMID: 35349154 DOI: 10.1007/978-1-0716-2132-5_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Analyzing protein movement dynamics and their regulation has shown to be important in the study of cell fate decisions. Such analyses can be performed with scanning fluorescence correlation spectroscopy (scanning FCS), a versatile imaging methodology that has been applied in the animal kingdom and recently adapted to the plant kingdom. Specifically, scanning FCS allows for qualitatively capturing protein movement across barriers, such as the active transport through plasmodesmata, the analysis of protein movement rates, and the quantification of the stoichiometry of protein complexes, composed of one or more different proteins. Importantly, the quantifiable data generated with scanning FCS can be used to inform computational models, enhancing model simulations of in vivo events, such as cell fate decisions, during plant development.
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Affiliation(s)
- Lisa Van den Broeck
- Plant and Microbial Biology Department, North Carolina State University, Raleigh, NC, USA
| | - Mariah Gobble
- Plant and Microbial Biology Department, North Carolina State University, Raleigh, NC, USA
| | - Rosangela Sozzani
- Plant and Microbial Biology Department, North Carolina State University, Raleigh, NC, USA.
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14
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Rapid ensemble measurement of protein diffusion and probe blinking dynamics in cells. BIOPHYSICAL REPORTS 2021; 1:100015. [PMID: 36425455 PMCID: PMC9680803 DOI: 10.1016/j.bpr.2021.100015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/30/2021] [Indexed: 12/25/2022]
Abstract
We present a fluorescence fluctuation image correlation analysis method that can rapidly and simultaneously measure the diffusion coefficient, photoblinking rates, and fraction of diffusing particles of fluorescent molecules in cells. Unlike other image correlation techniques, we demonstrated that our method could be applied irrespective of a nonuniformly distributed, immobile blinking fluorophore population. This allows us to measure blinking and transport dynamics in complex cell morphologies, a benefit for a range of super-resolution fluorescence imaging approaches that rely on probe emission blinking. Furthermore, we showed that our technique could be applied without directly accounting for photobleaching. We successfully employed our technique on several simulations with realistic EMCCD noise and photobleaching models, as well as on Dronpa-C12-labeled β-actin in living NIH/3T3 and HeLa cells. We found that the diffusion coefficients measured using our method were consistent with previous literature values. We further found that photoblinking rates measured in the live HeLa cells varied as expected with changing excitation power.
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15
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Oasa S, Krmpot AJ, Nikolić SN, Clayton AHA, Tsigelny IF, Changeux JP, Terenius L, Rigler R, Vukojević V. Dynamic Cellular Cartography: Mapping the Local Determinants of Oligodendrocyte Transcription Factor 2 (OLIG2) Function in Live Cells Using Massively Parallel Fluorescence Correlation Spectroscopy Integrated with Fluorescence Lifetime Imaging Microscopy (mpFCS/FLIM). Anal Chem 2021; 93:12011-12021. [PMID: 34428029 PMCID: PMC8427561 DOI: 10.1021/acs.analchem.1c02144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
Compartmentalization
and integration of molecular
processes through diffusion are basic mechanisms through which cells
perform biological functions. To characterize these mechanisms in
live cells, quantitative and ultrasensitive analytical methods with
high spatial and temporal resolution are needed. Here, we present
quantitative scanning-free confocal microscopy with single-molecule
sensitivity, high temporal resolution (∼10 μs/frame),
and fluorescence lifetime imaging capacity, developed by integrating
massively parallel fluorescence correlation spectroscopy with fluorescence
lifetime imaging microscopy (mpFCS/FLIM); we validate the method,
use it to map in live cell location-specific variations in the concentration,
diffusion, homodimerization, DNA binding, and local environment of
the oligodendrocyte transcription factor 2 fused with the enhanced
Green Fluorescent Protein (OLIG2-eGFP), and characterize the effects
of an allosteric inhibitor of OLIG2 dimerization on these determinants
of OLIG2 function. In particular, we show that cytoplasmic OLIG2-eGFP
is largely monomeric and freely diffusing, with the fraction of freely
diffusing OLIG2-eGFP molecules being fD,freecyt = (0.75
± 0.10) and the diffusion time τD,freecyt = (0.5 ± 0.3) ms. In contrast,
OLIG2-eGFP homodimers are abundant in the cell nucleus, constituting
∼25% of the nuclear pool, some fD,boundnuc = (0.65
± 0.10) of nuclear OLIG2-eGFP is bound to chromatin DNA, whereas
freely moving OLIG2-eGFP molecules diffuse at the same rate as those
in the cytoplasm, as evident from the lateral diffusion times τD,freenuc = τD,freecyt = (0.5
± 0.3) ms. OLIG2-eGFP interactions with chromatin DNA, revealed
through their influence on the apparent diffusion behavior of OLIG2-eGFP,
τD,boundnuc (850 ± 500) ms, are characterized by an apparent dissociation
constant Kd,appOLIG2-DNA = (45 ± 30) nM. The apparent
dissociation constant of OLIG2-eGFP homodimers was estimated to be Kd,app(OLIG2-eGFP)2 ≈ 560 nM. The allosteric inhibitor of OLIG2 dimerization,
compound NSC 50467, neither affects OLIG2-eGFP properties in the cytoplasm
nor does it alter the overall cytoplasmic environment. In contrast,
it significantly impedes OLIG2-eGFP homodimerization in the cell nucleus,
increasing five-fold the apparent dissociation constant, Kd,app,NSC50467(OLIG2-eGFP)2 ≈ 3 μM, thus reducing homodimer levels to below 7%
and effectively abolishing OLIG2-eGFP specific binding to chromatin
DNA. The mpFCS/FLIM methodology has a myriad of applications in biomedical
research and pharmaceutical industry. For example, it is indispensable
for understanding how biological functions emerge through the dynamic
integration of location-specific molecular processes and invaluable
for drug development, as it allows us to quantitatively characterize
the interactions of drugs with drug targets in live cells.
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Affiliation(s)
- Sho Oasa
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176 Stockholm, Sweden
| | - Aleksandar J Krmpot
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176 Stockholm, Sweden.,Institute of Physics Belgrade, University of Belgrade, 11080 Belgrade, Serbia
| | - Stanko N Nikolić
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176 Stockholm, Sweden.,Institute of Physics Belgrade, University of Belgrade, 11080 Belgrade, Serbia
| | - Andrew H A Clayton
- Optical Sciences Centre, Department of Physics and Astronomy, School of Science, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Igor F Tsigelny
- Department of Neurosciences, University of California San Diego, La Jolla, California 92093-0819, United States
| | - Jean-Pierre Changeux
- Department of Neuroscience, Unité Neurobiologie Intégrative des Systèmes Cholinergiques, Institut Pasteur, F-75724 Paris 15, France
| | - Lars Terenius
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176 Stockholm, Sweden
| | - Rudolf Rigler
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176 Stockholm, Sweden.,Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, 17177 Stockholm, Sweden
| | - Vladana Vukojević
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176 Stockholm, Sweden
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16
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Rose M, Kurylowicz M, Mahmood M, Winkel S, Moran-Mirabal JM, Fradin C. Direct Measurement of the Affinity between tBid and Bax in a Mitochondria-Like Membrane. Int J Mol Sci 2021; 22:8240. [PMID: 34361006 PMCID: PMC8348223 DOI: 10.3390/ijms22158240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 01/05/2023] Open
Abstract
The execution step in apoptosis is the permeabilization of the outer mitochondrial membrane, controlled by Bcl-2 family proteins. The physical interactions between the different proteins in this family and their relative abundance literally determine the fate of the cells. These interactions, however, are difficult to quantify, as they occur in a lipid membrane and involve proteins with multiple conformations and stoichiometries which can exist both in soluble and membrane. Here we focus on the interaction between two core Bcl-2 family members, the executor pore-forming protein Bax and the truncated form of the activator protein Bid (tBid), which we imaged at the single particle level in a mitochondria-like planar supported lipid bilayer. We inferred the conformation of the proteins from their mobility, and detected their transient interactions using a novel single particle cross-correlation analysis. We show that both tBid and Bax have at least two different conformations at the membrane, and that their affinity for one another increases by one order of magnitude (with a 2D-KD decreasing from ≃1.6μm-2 to ≃0.1μm-2) when they pass from their loosely membrane-associated to their transmembrane form. We conclude by proposing an updated molecular model for the activation of Bax by tBid.
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Affiliation(s)
- Markus Rose
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Martin Kurylowicz
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Mohammad Mahmood
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Sheldon Winkel
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Jose M. Moran-Mirabal
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada;
| | - Cécile Fradin
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
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17
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Bernabé-Rubio M, Bosch-Fortea M, Alonso MA, Bernardino de la Serna J. Multi-dimensional and spatiotemporal correlative imaging at the plasma membrane of live cells to determine the continuum nano-to-micro scale lipid adaptation and collective motion. Methods 2021; 193:136-147. [PMID: 34126167 DOI: 10.1016/j.ymeth.2021.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 12/25/2022] Open
Abstract
The primary cilium is a specialized plasma membrane protrusion with important receptors for signalling pathways. In polarized epithelial cells, the primary cilium assembles after the midbody remnant (MBR) encounters the centrosome at the apical surface. The membrane surrounding the MBR, namely remnant-associated membrane patch (RAMP), once situated next to the centrosome, releases some of its lipid components to form a centrosome-associated membrane patch (CAMP) from which the ciliary membrane stems. The RAMP undergoes a spatiotemporal membrane refinement during the formation of the CAMP, which becomes highly enriched in condensed membranes with low lateral mobility. To better understand this process, we have developed a correlative imaging approach that yields quantitative information about the lipid lateral packing, its mobility and collective assembly at the plasma membrane at different spatial scales over time. Our work paves the way towards a quantitative understanding of the spatiotemporal lipid collective assembly at the plasma membrane as a functional determinant in cell biology and its direct correlation with the membrane physicochemical state. These findings allowed us to gain a deeper insight into the mechanisms behind the biogenesis of the ciliary membrane of polarized epithelial cells.
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Affiliation(s)
- Miguel Bernabé-Rubio
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid 28049, Spain; King's College London Centre for Stem Cells and Regenerative Medicine, 28th Floor, Tower Wing, Guy's Campus, Great Maze Pond, London SE1 9RT, UK
| | - Minerva Bosch-Fortea
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid 28049, Spain; Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Miguel A Alonso
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Jorge Bernardino de la Serna
- Central Laser Facility, Rutherford Appleton Laboratory, MRC-Research Complex at Harwell, Science and Technology Facilities Council, Harwell OX11 0QX, UK; National Heart and Lung Institute, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ, UK; NIHR Imperial Biomedical Research Centre, London SW7 2AZ, UK.
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18
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Application of Advanced Light Microscopy to the Study of HIV and Its Interactions with the Host. Viruses 2021; 13:v13020223. [PMID: 33535486 PMCID: PMC7912744 DOI: 10.3390/v13020223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/24/2022] Open
Abstract
This review highlights the significant observations of human immunodeficiency virus (HIV) assembly, release and maturation made possible with advanced light microscopy techniques. The advances in technology which now enables these light microscopy measurements are discussed with special emphasis on live imaging approaches including Total Internal Reflection Fluorescence (TIRF), high-resolution light microscopy techniques including PALM and STORM and single molecule measurements, including Fluorescence Resonance Energy Transfer (FRET). The review concludes with a discussion on what new insights and understanding can be expected from these measurements.
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19
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Lateral diffusion of CD14 and TLR2 in macrophage plasma membrane assessed by raster image correlation spectroscopy and single particle tracking. Sci Rep 2020; 10:19375. [PMID: 33168941 PMCID: PMC7652837 DOI: 10.1038/s41598-020-76272-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/23/2020] [Indexed: 01/02/2023] Open
Abstract
The diffusion of membrane receptors is central to many biological processes, such as signal transduction, molecule translocation, and ion transport, among others; consequently, several advanced fluorescence microscopy techniques have been developed to measure membrane receptor mobility within live cells. The membrane-anchored receptor cluster of differentiation 14 (CD14) and the transmembrane toll-like receptor 2 (TLR2) are important receptors in the plasma membrane of macrophages that activate the intracellular signaling cascade in response to pathogenic stimuli. The aim of the present work was to compare the diffusion coefficients of CD14 and TLR2 on the apical and basal membranes of macrophages using two fluorescence-based methods: raster image correlation spectroscopy (RICS) and single particle tracking (SPT). In the basal membrane, the diffusion coefficients obtained from SPT and RICS were found to be comparable and revealed significantly faster diffusion of CD14 compared with TLR2. In addition, RICS showed that the diffusion of both receptors was significantly faster in the apical membrane than in the basal membrane, suggesting diffusion hindrance by the adhesion of the cells to the substrate. This finding highlights the importance of selecting the appropriate membrane (i.e., basal or apical) and corresponding method when measuring receptor diffusion in live cells. Accurately knowing the diffusion coefficient of two macrophage receptors involved in the response to pathogen insults will facilitate the study of changes that occur in signaling in these cells as a result of aging and disease.
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20
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Titlow J, Robertson F, Järvelin A, Ish-Horowicz D, Smith C, Gratton E, Davis I. Syncrip/hnRNP Q is required for activity-induced Msp300/Nesprin-1 expression and new synapse formation. J Cell Biol 2020; 219:133707. [PMID: 32040548 PMCID: PMC7055005 DOI: 10.1083/jcb.201903135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/21/2019] [Accepted: 12/12/2019] [Indexed: 01/09/2023] Open
Abstract
Memory and learning involve activity-driven expression of proteins and cytoskeletal reorganization at new synapses, requiring posttranscriptional regulation of localized mRNA a long distance from corresponding nuclei. A key factor expressed early in synapse formation is Msp300/Nesprin-1, which organizes actin filaments around the new synapse. How Msp300 expression is regulated during synaptic plasticity is poorly understood. Here, we show that activity-dependent accumulation of Msp300 in the postsynaptic compartment of the Drosophila larval neuromuscular junction is regulated by the conserved RNA binding protein Syncrip/hnRNP Q. Syncrip (Syp) binds to msp300 transcripts and is essential for plasticity. Single-molecule imaging shows that msp300 is associated with Syp in vivo and forms ribosome-rich granules that contain the translation factor eIF4E. Elevated neural activity alters the dynamics of Syp and the number of msp300:Syp:eIF4E RNP granules at the synapse, suggesting that these particles facilitate translation. These results introduce Syp as an important early acting activity-dependent regulator of a plasticity gene that is strongly associated with human ataxias.
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Affiliation(s)
- Joshua Titlow
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Aino Järvelin
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford, UK.,Medical Research Council Lab for Molecular Cell Biology, University College London, London, UK
| | - Carlas Smith
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, UK
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California Irvine, Irvine, CA
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford, UK
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21
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Rocha S, Hendrix J, Borrenberghs D, Debyser Z, Hofkens J. Imaging the Replication of Single Viruses: Lessons Learned from HIV and Future Challenges To Overcome. ACS NANO 2020; 14:10775-10783. [PMID: 32820634 DOI: 10.1021/acsnano.0c06369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The molecular composition of viral particles indicates that a single virion is capable of initiating an infection. However, the majority of viruses that come into contact with cells fails to infect them. Understanding what makes one viral particle more successful than others requires visualizing the infection process directly in living cells, one virion at a time. In this Perspective, we explain how single-virus imaging using fluorescence microscopy can provide answers to unsolved questions in virology. We discuss fluorescent labeling of virus particles, resolution at the subviral and molecular levels, tracking in living cells, and imaging of interactions between viral and host proteins. We end this Perspective with a set of remaining questions in understanding the life cycle of retroviruses and how imaging a single virus can help researchers address these questions. Although we use examples from the HIV field, these methods are of value for the study of other viruses as well.
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Affiliation(s)
- Susana Rocha
- Molecular Imaging and Photonics, Chemistry Department, KU Leuven, B-3001 Heverlee, Flanders, Belgium
| | - Jelle Hendrix
- Molecular Imaging and Photonics, Chemistry Department, KU Leuven, B-3001 Heverlee, Flanders, Belgium
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute (BIOMED), Hasselt University, B-3590 Diepenbeek, Flanders, Belgium
| | - Doortje Borrenberghs
- Molecular Imaging and Photonics, Chemistry Department, KU Leuven, B-3001 Heverlee, Flanders, Belgium
| | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, B-3001 Heverlee, Flanders, Belgium
| | - Johan Hofkens
- Molecular Imaging and Photonics, Chemistry Department, KU Leuven, B-3001 Heverlee, Flanders, Belgium
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
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22
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Louis B, Camacho R, Bresolí-Obach R, Abakumov S, Vandaele J, Kudo T, Masuhara H, Scheblykin IG, Hofkens J, Rocha S. Fast-tracking of single emitters in large volumes with nanometer precision. OPTICS EXPRESS 2020; 28:28656-28671. [PMID: 32988132 DOI: 10.1364/oe.401557] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Multifocal plane microscopy allows for capturing images at different focal planes simultaneously. Using a proprietary prism which splits the emitted light into paths of different lengths, images at 8 different focal depths were obtained, covering a volume of 50x50x4 µm3. The position of single emitters was retrieved using a phasor-based approach across the different imaging planes, with better than 10 nm precision in the axial direction. We validated the accuracy of this approach by tracking fluorescent beads in 3D to calculate water viscosity. The fast acquisition rate (>100 fps) also enabled us to follow the capturing of 0.2 µm fluorescent beads into an optical trap.
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23
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Black L, Tollis S, Fu G, Fiche JB, Dorsey S, Cheng J, Ghazal G, Notley S, Crevier B, Bigness J, Nollmann M, Tyers M, Royer CA. G1/S transcription factors assemble in increasing numbers of discrete clusters through G1 phase. J Cell Biol 2020; 219:151997. [PMID: 32744610 PMCID: PMC7480102 DOI: 10.1083/jcb.202003041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/20/2020] [Accepted: 05/26/2020] [Indexed: 02/03/2023] Open
Abstract
In budding yeast, the transcription factors SBF and MBF activate a large program of gene expression in late G1 phase that underlies commitment to cell division, termed Start. SBF/MBF are limiting with respect to target promoters in small G1 phase cells and accumulate as cells grow, raising the questions of how SBF/MBF are dynamically distributed across the G1/S regulon and how this impacts the Start transition. Super-resolution Photo-Activatable Localization Microscopy (PALM) mapping of the static positions of SBF/MBF subunits in fixed cells revealed each transcription factor was organized into discrete clusters containing approximately eight copies regardless of cell size and that the total number of clusters increased as cells grew through G1 phase. Stochastic modeling using reasonable biophysical parameters recapitulated growth-dependent SBF/MBF clustering and predicted TF dynamics that were confirmed in live cell PALM experiments. This spatio-temporal organization of SBF/MBF may help coordinate activation of G1/S regulon and the Start transition.
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Affiliation(s)
- Labe Black
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY
| | - Sylvain Tollis
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Guo Fu
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY
| | - Jean-Bernard Fiche
- Centre de Biochimie Structurale, Centre National de la Recherche Scientifique UMR5048, Institut National de la Santé et de la Recherche Médicale U1054, Université de Montpellier, Montpellier, France
| | - Savanna Dorsey
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY
| | - Jing Cheng
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Ghada Ghazal
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Stephen Notley
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY
| | - Benjamin Crevier
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY
| | - Jeremy Bigness
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY
| | - Marcelo Nollmann
- Centre de Biochimie Structurale, Centre National de la Recherche Scientifique UMR5048, Institut National de la Santé et de la Recherche Médicale U1054, Université de Montpellier, Montpellier, France
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Catherine Ann Royer
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY
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24
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Frost R, Débarre D, Jana S, Bano F, Schünemann J, Görlich D, Richter RP. A Method to Quantify Molecular Diffusion within Thin Solvated Polymer Films: A Case Study on Films of Natively Unfolded Nucleoporins. ACS NANO 2020; 14:9938-9952. [PMID: 32667780 PMCID: PMC7526988 DOI: 10.1021/acsnano.0c02895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/15/2020] [Indexed: 06/11/2023]
Abstract
We present a method to probe molecular and nanoparticle diffusion within thin, solvated polymer coatings. The device exploits the confinement with well-defined geometry that forms at the interface between a planar and a hemispherical surface (of which at least one is coated with polymers) in close contact and uses this confinement to analyze diffusion processes without interference of exchange with and diffusion in the bulk solution. With this method, which we call plane-sphere confinement microscopy (PSCM), information regarding the partitioning of molecules between the polymer coating and the bulk liquid is also obtained. Thanks to the shape of the confined geometry, diffusion and partitioning can be mapped as a function of compression and concentration of the coating in a single experiment. The method is versatile and can be integrated with conventional optical microscopes; thus it should find widespread use in the many application areas exploiting functional polymer coatings. We demonstrate the use of PSCM using brushes of natively unfolded nucleoporin domains rich in phenylalanine-glycine repeats (FG domains). A meshwork of FG domains is known to be responsible for the selective transport of nuclear transport receptors (NTRs) and their macromolecular cargos across the nuclear envelope that separates the cytosol and the nucleus of living cells. We find that the selectivity of NTR uptake by FG domain films depends sensitively on FG domain concentration and that the interaction of NTRs with FG domains obstructs NTR movement only moderately. These observations contribute important information to better understand the mechanisms of selective NTR transport.
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Affiliation(s)
- Rickard Frost
- School
of Biomedical Sciences, Faculty of Biological Sciences, School of
Physics and Astronomy, Faculty of Engineering and Physical Sciences,
Astbury Centre of Structural Molecular Biology, and Bragg Centre for
Materials Research, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | | | - Saikat Jana
- School
of Biomedical Sciences, Faculty of Biological Sciences, School of
Physics and Astronomy, Faculty of Engineering and Physical Sciences,
Astbury Centre of Structural Molecular Biology, and Bragg Centre for
Materials Research, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Fouzia Bano
- School
of Biomedical Sciences, Faculty of Biological Sciences, School of
Physics and Astronomy, Faculty of Engineering and Physical Sciences,
Astbury Centre of Structural Molecular Biology, and Bragg Centre for
Materials Research, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Jürgen Schünemann
- Department
of Cellular Logistics, Max Planck Institute
for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Dirk Görlich
- Department
of Cellular Logistics, Max Planck Institute
for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Ralf P. Richter
- School
of Biomedical Sciences, Faculty of Biological Sciences, School of
Physics and Astronomy, Faculty of Engineering and Physical Sciences,
Astbury Centre of Structural Molecular Biology, and Bragg Centre for
Materials Research, University of Leeds, Leeds, LS2 9JT, United Kingdom
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25
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Leichner J, Lin WC. Advances in imaging and analysis of 4 fluorescent components through the rat cortical column. J Neurosci Methods 2020; 341:108792. [PMID: 32446942 DOI: 10.1016/j.jneumeth.2020.108792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND Immunofluorescent staining coupled with axial optical sectioning allows for assessment of native three-dimensional structure of brain tissue. Typical challenges of analyzing network structure include limitations driven by magnification/field of view, spatial resolution, tissue thickness, staining quality of dense cell types, data quantifiability and the quantity of simultaneous staining targets. NEW METHOD This manuscript demonstrates many methodological advancements. Software-aided alignment of the cortical slice and stereotaxic atlas maximizes ROI-identification accuracy. Tissue compression during antigen retrieval enhances epitope availability without damaging tissue. A thorough factorial experiment focusing on Smi-311 staining highlights the enhancements in image quality from our extended staining protocol. Mosaic scanning techniques and subsequent four-channel alignment ensures high data quality. RESULTS Cortical column datasets [800μm x 3000μm x 70μm] utilizing sequential optical sectioning were successfully generated from three rats. Each rat provided three coronal sections in each of two regions, M1 and S1BF, from which data cubes were generated per hemisphere, totaling 36 high-magnification four-color datasets. COMPARISON WITH EXISTING METHOD(S) Typical confocal assessments of brain tissue do not utilize such thick tissue slices nor collect entire cortical columns from the cortical surface to the grey/white interface at a resolution that can map fine filamentous processes. The simultaneous collection of our four specific structural markers - neuronal, astrocytic, vascular and nuclear - is novel and the quantitative optimization of staining protocols through a factorial design rare. CONCLUSIONS Building upon this preliminary success in protocol development, future work will encompass volumetric modeling and quantitative analysis of regional network architecture.
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Affiliation(s)
- Jared Leichner
- Biomedical Engineering Creative Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, Miami, FL 33174, USA
| | - Wei-Chiang Lin
- Biomedical Engineering Creative Laboratory, Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, Miami, FL 33174, USA.
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26
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Gabriel M, Navarro GSC, de Borba L, Rossi AH, Gamarnik AV, Estrada LC. Dengue Virus Capsid Protein Dynamics Reveals Spatially Heterogeneous Motion in Live-Infected-Cells. Sci Rep 2020; 10:8751. [PMID: 32472078 PMCID: PMC7260208 DOI: 10.1038/s41598-020-65625-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 05/05/2020] [Indexed: 11/15/2022] Open
Abstract
Dengue is the single most important human viral infection transmitted by insects. The function of the viral proteins andtheir interactions with the host cell is under exhaustive investigation with the aim of identifying antiviral strategies. Here,using recombinant full-length dengue virus genomes, carrying a fluorescent mCherry fused to capsid, we studied biophysicalproperties of the viral protein during one infectious cycle in living cells. Dengue virus capsid protein associates to differentcellular compartments but its function in these locations is largely unknown. We evaluated the diffusion of capsid inside the celland determined a higher effective diffusion coefficient in the cytoplasm than in the nucleus. Using advanced fluorescencecorrelation methods, including the recently developed two-dimensional pair correlation analysis, we constructed for the first timehigh resolution maps of capsid mobility in an infected cell. We observed that the motion of capsid in the nucleoplasm-nucleolusinterface was highly organized, indicating an obstacle in this interface. Although nucleoli are membraneless structures, theydisplayed liquid-liquid phase separation. Once inside nucleoli, the protein showed isotropic mobility, indicating free diffusion orimmobilized capsid inside these structures. This is the first study presenting spatial and temporal dynamics of the dengue viruscapsid protein during infection.
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Affiliation(s)
- Manuela Gabriel
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA-National Research Council for Science and Technology (CONICET), Buenos Aires, 1428, Argentina
| | - Guadalupe S Costa Navarro
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires, 1405, Argentina
| | - Luana de Borba
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires, 1405, Argentina
| | - Andrés H Rossi
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires, 1405, Argentina
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-National Research Council for Science and Technology (CONICET), Buenos Aires, 1405, Argentina
| | - Laura C Estrada
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA-National Research Council for Science and Technology (CONICET), Buenos Aires, 1428, Argentina.
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27
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DE Mets R, Delon A, Balland M, Destaing O, Wang I. Dynamic range and background filtering in raster image correlation spectroscopy. J Microsc 2020; 279:123-138. [PMID: 32441342 DOI: 10.1111/jmi.12925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 05/04/2020] [Accepted: 05/18/2020] [Indexed: 11/28/2022]
Abstract
Raster-scan image correlation spectroscopy (RICS) enables researchers to measure molecular translational diffusion constants and concentrations from standard confocal laser scanning microscope images and is suitable for measuring a wide range of mobility, especially fast-diffusing molecules. However, as RICS analysis is based on the spatial autocorrelation function of fluorescence images, it is sensitive to the presence of fluorescent structures within the image. In this study, we investigate methods to filter out immobile or slow moving background structures and their impact on RICS results. Both the conventional moving-average subtraction-based method and cross-correlation subtraction-based method are rationalized and quantified. Simulated data and experimental measurements in living cells stress the importance of optimizing the temporal resolution of background filtering for reliable RICS measurements. Finally, the capacity of RICS analysis to separate two species is studied.
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Affiliation(s)
- R DE Mets
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France.,Mechanobiology Institute, National University of Singapore, Singapore
| | - A Delon
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
| | - M Balland
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
| | - O Destaing
- Institute for Advanced Biosciences, Université Grenoble Alpes, Grenoble, France
| | - I Wang
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
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28
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Jonkman J, Brown CM, Wright GD, Anderson KI, North AJ. Tutorial: guidance for quantitative confocal microscopy. Nat Protoc 2020. [PMID: 32235926 DOI: 10.1038/s41596-020-0313-319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
When used appropriately, a confocal fluorescence microscope is an excellent tool for making quantitative measurements in cells and tissues. The confocal microscope's ability to block out-of-focus light and thereby perform optical sectioning through a specimen allows the researcher to quantify fluorescence with very high spatial precision. However, generating meaningful data using confocal microscopy requires careful planning and a thorough understanding of the technique. In this tutorial, the researcher is guided through all aspects of acquiring quantitative confocal microscopy images, including optimizing sample preparation for fixed and live cells, choosing the most suitable microscope for a given application and configuring the microscope parameters. Suggestions are offered for planning unbiased and rigorous confocal microscope experiments. Common pitfalls such as photobleaching and cross-talk are addressed, as well as several troubling instrumentation problems that may prevent the acquisition of quantitative data. Finally, guidelines for analyzing and presenting confocal images in a way that maintains the quantitative nature of the data are presented, and statistical analysis is discussed. A visual summary of this tutorial is available as a poster (https://doi.org/10.1038/s41596-020-0307-7).
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Affiliation(s)
- James Jonkman
- Advanced Optical Microscopy Facility (AOMF), University Health Network, Toronto, Ontario, Canada.
| | - Claire M Brown
- Advanced BioImaging Facility (ABIF), McGill University, Montreal, Quebec, Canada
| | - Graham D Wright
- A*STAR Microscopy Platform (AMP), Skin Research Institute of Singapore, A*STAR, Singapore, Singapore
| | - Kurt I Anderson
- Crick Advanced Light Microscopy Facility (CALM), The Francis Crick Institute, London, UK
| | - Alison J North
- Bio-Imaging Resource Center, The Rockefeller University, New York, NY, USA
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29
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Bourges AC, Lazarev A, Declerck N, Rogers KL, Royer CA. Quantitative High-Resolution Imaging of Live Microbial Cells at High Hydrostatic Pressure. Biophys J 2020; 118:2670-2679. [PMID: 32402241 DOI: 10.1016/j.bpj.2020.04.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/19/2020] [Accepted: 04/16/2020] [Indexed: 10/24/2022] Open
Abstract
The majority of the Earth's microbial biomass exists in the deep biosphere, in the deep ocean, and within the Earth's crust. Although other physical parameters in these environments, such as temperature or pH, can differ substantially, they are all under high pressures. Beyond emerging genomic information, little is known about the molecular mechanisms underlying the ability of these organisms to survive and grow at pressures that can reach over 1000-fold the pressure on the Earth's surface. The mechanisms of pressure adaptation are also important in food safety, with the increasing use of high-pressure food processing. Advanced imaging represents an important tool for exploring microbial adaptation and response to environmental changes. Here, we describe implementation of a high-pressure sample chamber with a two-photon scanning microscope system, allowing for the first time, to our knowledge, quantitative high-resolution two-photon imaging at 100 MPa of living microbes from all three kingdoms of life. We adapted this setup for fluorescence lifetime imaging microscopy with phasor analysis (FLIM/Phasor) and investigated metabolic responses to pressure of live cells from mesophilic yeast and bacterial strains, as well as the piezophilic archaeon Archaeoglobus fulgidus. We also monitored by fluorescence intensity fluctuation-based methods (scanning number and brightness and raster scanning imaging correlation spectroscopy) the effect of pressure on the chromosome-associated protein HU and on the ParB partition protein in Escherichia coli, revealing partially reversible dissociation of ParB foci and concomitant nucleoid condensation. These results provide a proof of principle that quantitative, high-resolution imaging of live microbial cells can be carried out at pressures equivalent to those in the deepest ocean trenches.
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Affiliation(s)
- Anais C Bourges
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York; Centre de Biochimie Structrurale (CBS), INSERM, CNRS, Université de Montpellier, Montpellier, France; INRAE, MICA Department, Jouy-en-Josas, France
| | | | - Nathalie Declerck
- Centre de Biochimie Structrurale (CBS), INSERM, CNRS, Université de Montpellier, Montpellier, France; INRAE, MICA Department, Jouy-en-Josas, France
| | - Karyn L Rogers
- Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, New York
| | - Catherine A Royer
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York.
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30
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Jonkman J, Brown CM, Wright GD, Anderson KI, North AJ. Tutorial: guidance for quantitative confocal microscopy. Nat Protoc 2020; 15:1585-1611. [DOI: 10.1038/s41596-020-0313-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 02/10/2020] [Indexed: 01/04/2023]
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31
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Scales N, Swain PS. Resolving fluorescent species by their brightness and diffusion using correlated photon-counting histograms. PLoS One 2019; 14:e0226063. [PMID: 31887113 PMCID: PMC6936799 DOI: 10.1371/journal.pone.0226063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 11/19/2019] [Indexed: 12/27/2022] Open
Abstract
Fluorescence fluctuation spectroscopy (FFS) refers to techniques that analyze fluctuations in the fluorescence emitted by fluorophores diffusing in a small volume and can be used to distinguish between populations of molecules that exhibit differences in brightness or diffusion. For example, fluorescence correlation spectroscopy (FCS) resolves species through their diffusion by analyzing correlations in the fluorescence over time; photon counting histograms (PCH) and related methods based on moment analysis resolve species through their brightness by analyzing fluctuations in the photon counts. Here we introduce correlated photon counting histograms (cPCH), which uses both types of information to simultaneously resolve fluorescent species by their brightness and diffusion. We define the cPCH distribution by the probability to detect both a particular number of photons at the current time and another number at a later time. FCS and moment analysis are special cases of the moments of the cPCH distribution, and PCH is obtained by summing over the photon counts in either channel. cPCH is inherently a dual channel technique, and the expressions we develop apply to the dual colour case. Using simulations, we demonstrate that two species differing in both their diffusion and brightness can be better resolved with cPCH than with either FCS or PCH. Further, we show that cPCH can be extended both to longer dwell times to improve the signal-to-noise and to the analysis of images. By better exploiting the information available in fluorescence fluctuation spectroscopy, cPCH will be an enabling methodology for quantitative biology.
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Affiliation(s)
- Nathan Scales
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6, Canada
| | - Peter S. Swain
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6, Canada
- School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3BF, United Kingdom
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32
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Interferometric fluorescence cross correlation spectroscopy. PLoS One 2019; 14:e0225797. [PMID: 31851670 PMCID: PMC6919592 DOI: 10.1371/journal.pone.0225797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/12/2019] [Indexed: 11/20/2022] Open
Abstract
Measuring transport properties like diffusion and directional flow is essential for understanding dynamics within heterogeneous systems including living cells and novel materials. Fluorescent molecules traveling within these inhomogeneous environments under the forces of Brownian motion and flow exhibit fluctuations in their concentration, which are directly linked to the transport properties. We present a method utilizing single photon interference and fluorescence correlation spectroscopy (FCS) to simultaneously measure transport of fluorescent molecules within aqueous samples. Our method, within seconds, measures transport in thousands of homogenous voxels (100 nm)3 and under certain conditions, eliminates photo-physical artifacts associated with blinking of fluorescent molecules. A comprehensive theoretical framework is presented and validated by measuring transport of quantum dots, associated with VSV-G receptor along cellular membranes as well as within viscous gels.
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33
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Planes N, Vanderheyden PPML, Gratton E, Caballero-George C. Image mean square displacement to study the lateral mobility of Angiotensin II type 1 and Endothelin 1 type A receptors on living cells. Microsc Res Tech 2019; 83:381-392. [PMID: 31837080 DOI: 10.1002/jemt.23425] [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: 11/13/2019] [Accepted: 12/02/2019] [Indexed: 11/10/2022]
Abstract
The lateral mobility of membrane receptors provides insights into the molecular interactions of protein binding and the complex dynamic plasma membrane. The image mean square displacement (iMSD) analysis is a method used to extract qualitative and quantitative information of the protein diffusion law and infers how diffusion dynamic processes may change when the cellular environment is modified. The aim of the study was to describe the membrane diffusing properties of two G-protein-coupled receptors namely Angiotensin II type 1 (AT1 ) and Endothelin 1 type A (ETA ) receptors and their corresponding receptor-ligand complexes in living cells using total internal reflection fluorescent microscopy and iMSD analysis. This study showed that both AT1 and ETA receptors displayed a mix of three modes of diffusion: free, confined, and partially confined. The confined mode was the predominant at the plasma membrane of living cells and was not affected by ligand binding. However, the local diffusivity and the confinement zone of AT1 receptors were reduced by the binding of its antagonist losartan, and the long-range diffusion with the local diffusivity coefficient of ETA receptors was reduced upon exposure to its antagonist BQ123. To the best of our knowledge, this is the first study addressing the protein diffusion laws of these two receptors on living cells using total internal reflection fluorescence microscopy and iMSD.
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Affiliation(s)
- Nadir Planes
- Center of Innovation and Technology Transfer, Institute of Scientific Research and High Technology Services (INDICASAT AIP), Panama City, Panama.,Department of Biotechnology, Acharya Nagarjuna University, Guntur, Andhra Pradesh, India
| | | | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Catherina Caballero-George
- Center of Innovation and Technology Transfer, Institute of Scientific Research and High Technology Services (INDICASAT AIP), Panama City, Panama
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34
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Longfils M, Smisdom N, Ameloot M, Rudemo M, Lemmens V, Fernández GS, Röding M, Lorén N, Hendrix J, Särkkä A. Raster Image Correlation Spectroscopy Performance Evaluation. Biophys J 2019; 117:1900-1914. [PMID: 31668746 PMCID: PMC7018992 DOI: 10.1016/j.bpj.2019.09.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/28/2019] [Accepted: 09/30/2019] [Indexed: 01/02/2023] Open
Abstract
Raster image correlation spectroscopy (RICS) is a fluorescence image analysis method for extracting the mobility, concentration, and stoichiometry of diffusing fluorescent molecules from confocal image stacks. The method works by calculating a spatial correlation function for each image and analyzing the average of those by model fitting. Rules of thumb exist for RICS image acquisitioning, yet a rigorous theoretical approach to predict the accuracy and precision of the recovered parameters has been lacking. We outline explicit expressions to reveal the dependence of RICS results on experimental parameters. In terms of imaging settings, we observed that a twofold decrease of the pixel size, e.g., from 100 to 50 nm, decreases the error on the translational diffusion constant (D) between three- and fivefold. For D = 1 μm2 s-1, a typical value for intracellular measurements, ∼25-fold lower mean-squared relative error was obtained when the optimal scan speed was used, although more drastic improvements were observed for other values of D. We proposed a slightly modified RICS calculation that allows correcting for the significant bias of the autocorrelation function at small (≪50 × 50 pixels) sizes of the region of interest. In terms of sample properties, at molecular brightness E = 100 kHz and higher, RICS data quality was sufficient using as little as 20 images, whereas the optimal number of frames for lower E scaled pro rata. RICS data quality was constant over the nM-μM concentration range. We developed a bootstrap-based confidence interval of D that outperformed the classical least-squares approach in terms of coverage probability of the true value of D. We validated the theory via in vitro experiments of enhanced green fluorescent protein at different buffer viscosities. Finally, we outline robust practical guidelines and provide free software to simulate the parameter effects on recovery of the diffusion coefficient.
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Affiliation(s)
- Marco Longfils
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden.
| | - Nick Smisdom
- Stadius Centre for Dynamical Systems, Signal Processing and Data Analytics, KU Leuven, Leuven, Belgium; Advanced Optical Microscopy Centre, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Marcel Ameloot
- Advanced Optical Microscopy Centre, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Mats Rudemo
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden
| | - Veerle Lemmens
- Advanced Optical Microscopy Centre, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium; Dynamic Bioimaging Lab, Hasselt University, Diepenbeek, Belgium; Molecular Imaging and Photonics, Chemistry Department, KU Leuven, Heverlee, Belgium
| | | | | | - Niklas Lorén
- RISE Bioscience and Materials, Gothenburg, Sweden; Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Jelle Hendrix
- Advanced Optical Microscopy Centre, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium; Dynamic Bioimaging Lab, Hasselt University, Diepenbeek, Belgium.
| | - Aila Särkkä
- Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden
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35
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Abstract
Receptor tyrosine kinases (RTKs) play important roles in cell growth, motility, differentiation, and survival. These single-pass membrane proteins are grouped into subfamilies based on the similarity of their extracellular domains. They are generally thought to be activated by ligand binding, which promotes homodimerization and then autophosphorylation in trans. However, RTK interactions are more complicated, as RTKs can interact in the absence of ligand and heterodimerize within and across subfamilies. Here, we review the known cross-subfamily RTK heterointeractions and their possible biological implications, as well as the methodologies which have been used to study them. Moreover, we demonstrate how thermodynamic models can be used to study RTKs and to explain many of the complicated biological effects which have been described in the literature. Finally, we discuss the concept of the RTK interactome: a putative, extensive network of interactions between the RTKs. This RTK interactome can produce unique signaling outputs; can amplify, inhibit, and modify signaling; and can allow for signaling backups. The existence of the RTK interactome could provide an explanation for the irreproducibility of experimental data from different studies and for the failure of some RTK inhibitors to produce the desired therapeutic effects. We argue that a deeper knowledge of RTK interactome thermodynamics can lead to a better understanding of fundamental RTK signaling processes in health and disease. We further argue that there is a need for quantitative, thermodynamic studies that probe the strengths of the interactions between RTKs and their ligands and between different RTKs.
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Affiliation(s)
- Michael D. Paul
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore MD 21218
| | - Kalina Hristova
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore MD 21218
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36
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Obashi K, Matsuda A, Inoue Y, Okabe S. Precise Temporal Regulation of Molecular Diffusion within Dendritic Spines by Actin Polymers during Structural Plasticity. Cell Rep 2019; 27:1503-1515.e8. [DOI: 10.1016/j.celrep.2019.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 02/22/2019] [Accepted: 03/29/2019] [Indexed: 10/26/2022] Open
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37
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Abstract
Fluorescence recovery after photobleaching (FRAP) is an important tool used by cell biologists to study the diffusion and binding kinetics of vesicles, proteins, and other molecules in the cytoplasm, nucleus, or cell membrane. Although many FRAP models have been developed over the past decades, the influence of the complex boundaries of 3D cellular geometries on the recovery curves, in conjunction with regions of interest and optical effects (imaging, photobleaching, photoswitching, and scanning), has not been well studied. Here, we developed a 3D computational model of the FRAP process that incorporates particle diffusion, cell boundary effects, and the optical properties of the scanning confocal microscope, and validated this model using the tip-growing cells of Physcomitrella patens. We then show how these cell boundary and optical effects confound the interpretation of FRAP recovery curves, including the number of dynamic states of a given fluorophore, in a wide range of cellular geometries-both in two and three dimensions-namely nuclei, filopodia, and lamellipodia of mammalian cells, and in cell types such as the budding yeast, Saccharomyces pombe, and tip-growing plant cells. We explored the performance of existing analytical and algorithmic FRAP models in these various cellular geometries, and determined that the VCell VirtualFRAP tool provides the best accuracy to measure diffusion coefficients. Our computational model is not limited only to these cells types, but can easily be extended to other cellular geometries via the graphical Java-based application we also provide. This particle-based simulation-called the Digital Confocal Microscopy Suite or DCMS-can also perform fluorescence dynamics assays, such as number and brightness, fluorescence correlation spectroscopy, and raster image correlation spectroscopy, and could help shape the way these techniques are interpreted.
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38
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Visualizing the regulation of SLC34 proteins at the apical membrane. Pflugers Arch 2019; 471:533-542. [PMID: 30613865 DOI: 10.1007/s00424-018-02249-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
The cloning of the renal NaPi-2a (SLC34A1) and NaPi-2c (SLC34A3) phosphate transporters has made it possible to characterize the molecular and biophysical regulation of renal proximal tubular reabsorption of inorganic phosphate (Pi). Dietary factors, such as Pi and K, and several hormones and phosphatonins, including parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and glucocorticoids, regulate the transporters through various transcriptional, translational, and post-translational mechanisms that involve acute trafficking via endocytosis or exocytosis, interactions with PDZ domain proteins, lipid microdomains, and diffusion and clustering in the apical brush border membrane. The visualization of these trafficking events by means of novel microscopy techniques that includes fluorescence lifetime imaging microscopy (FLIM), Förster resonance energy transfer (FRET), fluctuation correlation spectroscopy (FCS), and modulation tracking (MT), is the primary focus of this review.
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39
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Cdc48/VCP Promotes Chromosome Morphogenesis by Releasing Condensin from Self-Entrapment in Chromatin. Mol Cell 2019; 69:664-676.e5. [PMID: 29452641 DOI: 10.1016/j.molcel.2018.01.030] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 11/04/2017] [Accepted: 01/22/2018] [Indexed: 01/26/2023]
Abstract
The morphological transformation of amorphous chromatin into distinct chromosomes is a hallmark of mitosis. To achieve this, chromatin must be compacted and remodeled by a ring-shaped enzyme complex known as condensin. However, the mechanistic basis underpinning condensin's role in chromosome remodeling has remained elusive. Here we show that condensin has a strong tendency to trap itself in its own reaction product during chromatin compaction and yet is capable of interacting with chromatin in a highly dynamic manner in vivo. To resolve this apparent paradox, we identified specific chromatin remodelers and AAA-class ATPases that act in a coordinated manner to release condensin from chromatin entrapment. The Cdc48 segregase is the central linchpin of this regulatory mechanism and promotes ubiquitin-dependent cycling of condensin on mitotic chromatin as well as effective chromosome condensation. Collectively, our results show that condensin inhibition by its own reaction product is relieved by forceful enzyme extraction from chromatin.
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40
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Moreno DF, Aldea M. Coincidence Analysis of Molecular Dynamics by Raster Image Correlation Spectroscopy. Methods Mol Biol 2019; 2040:375-384. [PMID: 31432488 DOI: 10.1007/978-1-4939-9686-5_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
The dynamics of cellular processes is a crucial aspect to consider when trying to understand cell function, particularly with regard to the coordination of complex mechanisms involving extensive molecular networks in different cell compartments. Thus, there is an urgent demand of methodologies able to obtain accurate spatiotemporal information on molecular dynamics in live cells. Different variants based on fluorescence correlation spectroscopy have been used successfully in the analysis of protein diffusion and complex or aggregation status. However, the available approaches are limited when simultaneous spatial and temporal resolutions are required to analyze fast processes. Here we describe the use of raster image correlation spectroscopy to analyze the spatiotemporal coincidence of collaborating proteins in highly dynamic molecular mechanisms.
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Affiliation(s)
- David F Moreno
- Molecular Biology Institute of Barcelona, IBMB-CSIC, Barcelona, Catalonia, Spain
| | - Martí Aldea
- Molecular Biology Institute of Barcelona, IBMB-CSIC, Barcelona, Catalonia, Spain.
- Department of Basic Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
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41
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Gegenfurtner FA, Zisis T, Al Danaf N, Schrimpf W, Kliesmete Z, Ziegenhain C, Enard W, Kazmaier U, Lamb DC, Vollmar AM, Zahler S. Transcriptional effects of actin-binding compounds: the cytoplasm sets the tone. Cell Mol Life Sci 2018; 75:4539-4555. [PMID: 30206640 PMCID: PMC11105542 DOI: 10.1007/s00018-018-2919-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/19/2018] [Accepted: 08/14/2018] [Indexed: 12/23/2022]
Abstract
Actin has emerged as a versatile regulator of gene transcription. Cytoplasmatic actin regulates mechanosensitive-signaling pathways such as MRTF-SRF and Hippo-YAP/TAZ. In the nucleus, both polymerized and monomeric actin directly interfere with transcription-associated molecular machineries. Natural actin-binding compounds are frequently used tools to study actin-related processes in cell biology. However, their influence on transcriptional regulation and intranuclear actin polymerization is poorly understood to date. Here, we analyze the effects of two representative actin-binding compounds, Miuraenamide A (polymerizing properties) and Latrunculin B (depolymerizing properties), on transcriptional regulation in primary cells. We find that actin stabilizing and destabilizing compounds inversely shift nuclear actin levels without a direct influence on polymerization state and intranuclear aspects of transcriptional regulation. Furthermore, we identify Miuraenamide A as a potent inducer of G-actin-dependent SRF target gene expression. In contrast, the F-actin-regulated Hippo-YAP/TAZ axis remains largely unaffected by compound-induced actin aggregation. This is due to the inability of AMOTp130 to bind to the amorphous actin aggregates resulting from treatment with miuraenamide. We conclude that actin-binding compounds predominantly regulate transcription via their influence on cytoplasmatic G-actin levels, while transcriptional processes relying on intranuclear actin polymerization or functional F-actin networks are not targeted by these compounds at tolerable doses.
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Affiliation(s)
- Florian A Gegenfurtner
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Themistoklis Zisis
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Nader Al Danaf
- Department of Chemistry, Munich Center for Integrated Protein Science, Nanosystems Initiative Munich and Centre for Nanoscience, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Waldemar Schrimpf
- Department of Chemistry, Munich Center for Integrated Protein Science, Nanosystems Initiative Munich and Centre for Nanoscience, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Zane Kliesmete
- Department Biology II, Anthropology and Human Genomics, Ludwig-Maximilians-University Munich, 82152, Martinsried, Germany
| | - Christoph Ziegenhain
- Department Biology II, Anthropology and Human Genomics, Ludwig-Maximilians-University Munich, 82152, Martinsried, Germany
| | - Wolfgang Enard
- Department Biology II, Anthropology and Human Genomics, Ludwig-Maximilians-University Munich, 82152, Martinsried, Germany
| | - Uli Kazmaier
- Institute of Organic Chemistry, Saarland University, 66041, Saarbrücken, Germany
| | - Don C Lamb
- Department of Chemistry, Munich Center for Integrated Protein Science, Nanosystems Initiative Munich and Centre for Nanoscience, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Angelika M Vollmar
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Stefan Zahler
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-University Munich, 81377, Munich, Germany.
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42
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Scipioni L, Lanzanó L, Diaspro A, Gratton E. Comprehensive correlation analysis for super-resolution dynamic fingerprinting of cellular compartments using the Zeiss Airyscan detector. Nat Commun 2018; 9:5120. [PMID: 30504919 PMCID: PMC6269422 DOI: 10.1038/s41467-018-07513-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/29/2018] [Indexed: 11/08/2022] Open
Abstract
The availability of the Airyscan detector in the Zeiss LSM 880 has made possible the development of a new concept in fluctuation correlation spectroscopy using super-resolution. The Airyscan unit acquires data simultaneously on 32 detectors arranged in a hexagonal array. This detector opens up the possibility to use fluctuation methods based on time correlation at single points or at a number of points simultaneously, as well as methods based on spatial correlation in the area covered by the detector. Given the frame rate of this detector, millions of frames can be acquired in seconds, providing a robust statistical basis for fluctuation data. We apply the comprehensive analysis to the molecular fluctuations of free GFP diffusing in live cells at different subcellular compartments to show that at the nanoscale different cell environments can be distinguished by the comprehensive fluctuation analysis.
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Affiliation(s)
- L Scipioni
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, 92697, CA, USA
| | - L Lanzanó
- Nanoscopy, Istituto Italiano di Tecnologia, Genoa, 16163, Italy
| | - A Diaspro
- Nanoscopy, Istituto Italiano di Tecnologia, Genoa, 16163, Italy
- Nikon Imaging Center, Istituto Italiano di Tecnologia, Genoa, 16163, Italy
| | - E Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, 92697, CA, USA.
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43
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Gao X, Gao P, Prunsche B, Nienhaus K, Nienhaus GU. Pulsed interleaved excitation-based line-scanning spatial correlation spectroscopy (PIE-lsSCS). Sci Rep 2018; 8:16722. [PMID: 30425308 PMCID: PMC6233157 DOI: 10.1038/s41598-018-35146-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/31/2018] [Indexed: 11/09/2022] Open
Abstract
We report pulsed interleaved excitation (PIE) based line-scanning spatial correlation spectroscopy (PIE-lsSCS), a quantitative fluorescence microscopy method for the study of dynamics in free-standing lipid bilayer membranes. Using a confocal microscope, we scan multiple lines perpendicularly through the membrane, each one laterally displaced from the previous one by several ten nanometers. Scanning through the membrane enables us to eliminate intensity fluctuations due to membrane displacements with respect to the observation volume. The diffusion of fluorescent molecules within the membrane is quantified by spatial correlation analysis, based on the fixed lag times between successive line scans. PIE affords dual-color excitation within a single line scan and avoids channel crosstalk. PIE-lsSCS data are acquired from a larger membrane region so that sampling is more efficient. Moreover, the local photon flux is reduced compared with single-point experiments, resulting in a smaller fraction of photobleached molecules for identical exposure times. This is helpful for precise measurements on live cells and tissues. We have evaluated the method with experiments on fluorescently labeled giant unilamellar vesicles (GUVs) and membrane-stained live cells.
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Affiliation(s)
- Xiang Gao
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
| | - Peng Gao
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Benedikt Prunsche
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
| | - Karin Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
| | - Gerd Ulrich Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany.
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany.
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany.
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
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44
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Hoischen C, Monajembashi S, Weisshart K, Hemmerich P. Multimodal Light Microscopy Approaches to Reveal Structural and Functional Properties of Promyelocytic Leukemia Nuclear Bodies. Front Oncol 2018; 8:125. [PMID: 29888200 PMCID: PMC5980967 DOI: 10.3389/fonc.2018.00125] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 04/05/2018] [Indexed: 12/11/2022] Open
Abstract
The promyelocytic leukemia (pml) gene product PML is a tumor suppressor localized mainly in the nucleus of mammalian cells. In the cell nucleus, PML seeds the formation of macromolecular multiprotein complexes, known as PML nuclear bodies (PML NBs). While PML NBs have been implicated in many cellular functions including cell cycle regulation, survival and apoptosis their role as signaling hubs along major genome maintenance pathways emerged more clearly. However, despite extensive research over the past decades, the precise biochemical function of PML in these pathways is still elusive. It remains a big challenge to unify all the different previously suggested cellular functions of PML NBs into one mechanistic model. With the advent of genetically encoded fluorescent proteins it became possible to trace protein function in living specimens. In parallel, a variety of fluorescence fluctuation microscopy (FFM) approaches have been developed which allow precise determination of the biophysical and interaction properties of cellular factors at the single molecule level in living cells. In this report, we summarize the current knowledge on PML nuclear bodies and describe several fluorescence imaging, manipulation, FFM, and super-resolution techniques suitable to analyze PML body assembly and function. These include fluorescence redistribution after photobleaching, fluorescence resonance energy transfer, fluorescence correlation spectroscopy, raster image correlation spectroscopy, ultraviolet laser microbeam-induced DNA damage, erythrocyte-mediated force application, and super-resolution microscopy approaches. Since most if not all of the microscopic equipment to perform these techniques may be available in an institutional or nearby facility, we hope to encourage more researches to exploit sophisticated imaging tools for their research in cancer biology.
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45
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Stortz M, Angiolini J, Mocskos E, Wolosiuk A, Pecci A, Levi V. Mapping the dynamical organization of the cell nucleus through fluorescence correlation spectroscopy. Methods 2018; 140-141:10-22. [DOI: 10.1016/j.ymeth.2017.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/01/2017] [Accepted: 12/13/2017] [Indexed: 11/28/2022] Open
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46
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Garcia E, Bernardino de la Serna J. Dissecting single-cell molecular spatiotemporal mobility and clustering at focal adhesions in polarised cells by fluorescence fluctuation spectroscopy methods. Methods 2018; 140-141:85-96. [PMID: 29605734 DOI: 10.1016/j.ymeth.2018.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/20/2018] [Accepted: 03/22/2018] [Indexed: 11/21/2022] Open
Abstract
Quantitative fluorescence fluctuation spectroscopy from optical microscopy datasets is a very powerful tool to resolve multiple spatiotemporal cellular and subcellular processes at the molecular level. In particular, raster image correlation spectroscopy (RICS) and number and brightness analyses (N&B) yield molecular mobility and clustering dynamic information extracted from real-time cellular processes. This quantitative information can be inferred in a highly flexible and detailed manner, i.e. 1) at the localisation level: from full-frame datasets and multiple regions of interest within; and 2) at the temporal level: not only from full-frame and multiple regions, but also intermediate temporal events. Here we build on previous research in deciphering the molecular dynamics of paxillin, a main component of focal adhesions. Cells use focal adhesions to attach to the extracellular matrix and interact with their local environment. Through focal adhesions and other adhesion structures, cells sense their local environment and respond accordingly; due to this continuous communication, these structures can be highly dynamic depending on the extracellular characteristics. By using a previously well-characterised model like paxillin, we examine the powerful sensitivity and some limitations of RICS and N&B analyses. We show that cells upon contact to different surfaces show differential self-assembly dynamics in terms of molecular diffusion and oligomerisation. In addition, single-cell studies show that these dynamics change gradually following an antero-posterior gradient.
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Affiliation(s)
- Esther Garcia
- Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Research Complex at Harwell, Harwell-Oxford, UK
| | - Jorge Bernardino de la Serna
- Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Research Complex at Harwell, Harwell-Oxford, UK; Department of Physics, King's College London, London, UK.
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47
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Kopp MRG, Villois A, Capasso Palmiero U, Arosio P. Microfluidic Diffusion Analysis of the Size Distribution and Microrheological Properties of Antibody Solutions at High Concentrations. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b00666] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marie R. G. Kopp
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, Swiss Federal Institute of Technology, Zurich, 8093, Switzerland
| | - Alessia Villois
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, Swiss Federal Institute of Technology, Zurich, 8093, Switzerland
| | - Umberto Capasso Palmiero
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, Swiss Federal Institute of Technology, Zurich, 8093, Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, Swiss Federal Institute of Technology, Zurich, 8093, Switzerland
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48
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Scipioni L, Di Bona M, Vicidomini G, Diaspro A, Lanzanò L. Local raster image correlation spectroscopy generates high-resolution intracellular diffusion maps. Commun Biol 2018; 1:10. [PMID: 30271897 PMCID: PMC6053083 DOI: 10.1038/s42003-017-0010-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/15/2017] [Indexed: 01/01/2023] Open
Abstract
Raster image correlation spectroscopy (RICS) is a powerful method for measuring molecular diffusion in live cells directly from images acquired on a laser scanning microscope. However, RICS only provides single average diffusion coefficients from regions with a lateral size on the order of few micrometers, which means that its spatial resolution is mainly limited to the cellular level. Here we introduce the local RICS (L-RICS), an easy-to-use tool that generates high resolution maps of diffusion coefficients from images acquired on a laser scanning microscope. As an application we show diffusion maps of a green fluorescent protein (GFP) within the nucleus and within the nucleolus of live cells at an effective spatial resolution of 500 nm. We find not only that diffusion in the nucleolus is slowed down compared to diffusion in the nucleoplasm, but also that diffusion in the nucleolus is highly heterogeneous. Lorenzo Scipioni et al. present Local Raster Image Correlation Spectroscopy (L-RICS), a method for generating sub-micrometer diffusion maps. They apply L-RICS to GFP in live cells and find that diffusion coefficients differ between the nucleus and nucleolus and are highly heterogeneous within compartments.
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Affiliation(s)
- Lorenzo Scipioni
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.,Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genoa, Via All'Opera Pia, 13, 16145, Genoa, Italy
| | - Melody Di Bona
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.,Department of Physics, University of Genoa, via Dodecaneso 33, 16146, Genoa, Italy
| | - Giuseppe Vicidomini
- Molecular Microscopy and Spectroscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Alberto Diaspro
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.,Department of Physics, University of Genoa, via Dodecaneso 33, 16146, Genoa, Italy.,Nikon Imaging Center, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Luca Lanzanò
- Nanoscopy, Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy.
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49
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Tomasetti L, Breunig M. Preventing Obstructions of Nanosized Drug Delivery Systems by the Extracellular Matrix. Adv Healthc Mater 2018; 7. [PMID: 29121453 DOI: 10.1002/adhm.201700739] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/25/2017] [Indexed: 12/13/2022]
Abstract
Although nanosized drug delivery systems are promising tools for the treatment of severe diseases, the extracellular matrix (ECM) constitutes a major obstacle that endangers therapeutic success. Mobility of diffusing species is restricted not only by small pore size (down to as low as 3 nm) but also by electrostatic interactions with the network. This article evaluates commonly used in vitro models of ECM, analytical methods, and particle types with respect to their similarity to native conditions in the target tissue. In this cross-study evaluation, results from a wide variety of mobility studies are analyzed to discern general principles of particle-ECM interactions. For instance, cross-linked networks and a negative network charge are essential to reliably recapitulate key features of the native ECM. Commonly used ECM mimics comprised of one or two components can lead to mobility calculations which have low fidelity to in vivo results. In addition, analytical methods must be tailored to the properties of both the matrix and the diffusing species to deliver accurate results. Finally, nanoparticles must be sufficiently small to penetrate the matrix pores (ideally Rd/p < 0.5; d = particle diameter, p = pore size) and carry a neutral surface charge to avoid obstructions. Larger (Rd/p >> 1) or positively charged particles are trapped.
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Affiliation(s)
- Luise Tomasetti
- Department of Pharmaceutical Technology; University of Regensburg; Universitaetsstrasse 31 93040 Regensburg Germany
| | - Miriam Breunig
- Department of Pharmaceutical Technology; University of Regensburg; Universitaetsstrasse 31 93040 Regensburg Germany
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50
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Dominguez-Medina S, Chen S, Blankenburg J, Swanglap P, Landes CF, Link S. Measuring the Hydrodynamic Size of Nanoparticles Using Fluctuation Correlation Spectroscopy. Annu Rev Phys Chem 2017; 67:489-514. [PMID: 27215820 DOI: 10.1146/annurev-physchem-040214-121510] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fluctuation correlation spectroscopy (FCS) is a well-established analytical technique traditionally used to monitor molecular diffusion in dilute solutions, the dynamics of chemical reactions, and molecular processes inside living cells. In this review, we present the recent use of FCS for measuring the size of colloidal nanoparticles in solution. We review the theoretical basis and experimental implementation of this technique and its advantages and limitations. In particular, we show examples of the use of FCS to measure the size of gold nanoparticles, monitor the rotational dynamics of gold nanorods, and investigate the formation of protein coronas on nanoparticles.
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Affiliation(s)
| | - Sishan Chen
- Department of Chemistry, Rice University, Houston, Texas 77005;
| | - Jan Blankenburg
- Department of Chemistry, Rice University, Houston, Texas 77005;
| | | | - Christy F Landes
- Department of Chemistry, Rice University, Houston, Texas 77005; .,Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005.,Laboratory for Nanophotonics, Rice University, Houston, Texas 77005.,Smalley-Curl Institute, Rice University, Houston, Texas 77005
| | - Stephan Link
- Department of Chemistry, Rice University, Houston, Texas 77005; .,Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005.,Laboratory for Nanophotonics, Rice University, Houston, Texas 77005.,Smalley-Curl Institute, Rice University, Houston, Texas 77005
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