1
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Nasser M, Meller A. Lifetime-based analysis of binary fluorophores mixtures in the low photon count limit. iScience 2022; 25:103554. [PMID: 34977508 PMCID: PMC8689154 DOI: 10.1016/j.isci.2021.103554] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/18/2021] [Accepted: 11/30/2021] [Indexed: 11/28/2022] Open
Abstract
Single biomolecule sensing often requires the quantification of multiple fluorescent species. Here, we theoretically and experimentally use time-resolved fluorescence via Time Correlated Single Photon Counting (TCSPC) to accurately quantify fluorescent species with similar chromatic signatures. A modified maximum likelihood estimator is introduced to include two fluorophore species, with compensation of the instrument response function. We apply this algorithm to simulated data of a simplified two-fluorescent species model, as well as to experimental data of fluorophores' mixtures and to a model protein, doubly labeled with different fluorophores' ratio. We show that 100 to 200 photons per fluorophore, in a 10-ms timescale, are sufficient to provide an accurate estimation of the dyes' ratio on the model protein. Our results provide estimation for the desired photon integration time toward implementation of TCSPC in systems with fast occurring events, such as translocation of biomolecules through nanopores or single-molecule burst analyses experiments. Exact ratios of emission-similar dyes in binary mixtures were quantified by TCSPC MLE-based analysis with IRF compensation was implemented for two fluorescent dyes Dual dye bioconjugation on a model protein was quantified at limited photon counts
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Affiliation(s)
- Maisa Nasser
- Department of Biomedical Engineering, Technion - IIT, Haifa 32000, Israel
| | - Amit Meller
- Department of Biomedical Engineering, Technion - IIT, Haifa 32000, Israel
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2
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Brüggemann Y, Karajannis LS, Stanoev A, Stallaert W, Bastiaens PIH. Growth factor-dependent ErbB vesicular dynamics couple receptor signaling to spatially and functionally distinct Erk pools. Sci Signal 2021; 14:14/683/eabd9943. [PMID: 34006609 DOI: 10.1126/scisignal.abd9943] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Growth factor-dependent vesicular dynamics allow cells to regulate the spatial distribution of growth factor receptors and thereby their coupling to downstream signaling effectors that guide cellular responses. We found that the ErbB ligands epidermal growth factor (EGF) and heregulin (HRG) generated distinct spatiotemporal patterns of cognate receptor activities to activate distinct subcellular pools of the extracellular signal-regulated kinase (Erk). Sustained plasma membrane activity of the receptor tyrosine kinases ErbB2/ErbB3 signaled to Erk complexed with the scaffold protein KSR to promote promigratory EphA2 phosphorylation and cellular motility upon HRG stimulation. In contrast, receptor-saturating EGF stimuli caused proliferation-inducing transient activation of cytoplasmic Erk due to the rapid internalization of EGF receptors (EGFR or ErbB1) toward endosomes. Paradoxically, promigratory signaling mediated by Erk complexed to KSR was sustained at low EGF concentrations by vesicular recycling that maintained steady-state amounts of active, phosphorylated EGFR at the plasma membrane. Thus, the effect of ligand identity and concentration on determining ErbB vesicular dynamics constitutes a mechanism by which cells can transduce growth factor composition through spatially distinct Erk pools to enable functionally diverse cellular responses.
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Affiliation(s)
- Yannick Brüggemann
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str.11, 44227 Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Lisa S Karajannis
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str.11, 44227 Dortmund, Germany
| | - Angel Stanoev
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str.11, 44227 Dortmund, Germany
| | - Wayne Stallaert
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str.11, 44227 Dortmund, Germany
| | - Philippe I H Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Str.11, 44227 Dortmund, Germany. .,Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
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3
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Gavriljuk K, Scocozza B, Ghasemalizadeh F, Seidel H, Nandan AP, Campos-Medina M, Schmick M, Koseska A, Bastiaens PIH. A self-organized synthetic morphogenic liposome responds with shape changes to local light cues. Nat Commun 2021; 12:1548. [PMID: 33750780 PMCID: PMC7943604 DOI: 10.1038/s41467-021-21679-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/29/2021] [Indexed: 12/02/2022] Open
Abstract
Reconstituting artificial proto-cells capable of transducing extracellular signals into cytoskeletal changes can reveal fundamental principles of how non-equilibrium phenomena in cellular signal transduction affect morphogenesis. Here, we generated a Synthetic Morphogenic Membrane System (SynMMS) by encapsulating a dynamic microtubule (MT) aster and a light-inducible signaling system driven by GTP/ATP chemical potential into cell-sized liposomes. Responding to light cues in analogy to morphogens, this biomimetic design embodies basic principles of localized Rho-GTPase signal transduction that generate an intracellular MT-regulator signaling gradient. Light-induced signaling promotes membrane-deforming growth of MT-filaments by dynamically elevating the membrane-proximal tubulin concentration. The resulting membrane deformations enable recursive coupling of the MT-aster with the signaling system, which generates global self-organized morphologies that reorganize towards local external cues in dependence on prior shape. SynMMS thereby signifies a step towards bio-inspired engineering of self-organized cellular morphogenesis. The authors generated a Synthetic Morphogenic Membrane System by encapsulating a dynamic microtubule aster and a light-inducible signaling system driven by GTP/ATP chemical potential into cell-sized liposomes. This reconstitution of artificial proto-cells reveals how non-equilibrium phenomena affect cellular information processing in morphogenesis.
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Affiliation(s)
- Konstantin Gavriljuk
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Bruno Scocozza
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Farid Ghasemalizadeh
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Hans Seidel
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Akhilesh P Nandan
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany.,Cellular Computations and Learning, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Manuel Campos-Medina
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Malte Schmick
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Aneta Koseska
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany.,Cellular Computations and Learning, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Philippe I H Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany. .,Faculty of Chemistry and Chemical Biology, TU Dortmund, Dortmund, Germany.
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4
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Guo W, Kumar S, Görlitz F, Garcia E, Alexandrov Y, Munro I, Kelly DJ, Warren S, Thorpe P, Dunsby C, French P. Automated Fluorescence Lifetime Imaging High-Content Analysis of Förster Resonance Energy Transfer between Endogenously Labeled Kinetochore Proteins in Live Budding Yeast Cells. SLAS Technol 2019; 24:308-320. [PMID: 30629461 PMCID: PMC6537140 DOI: 10.1177/2472630318819240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/16/2018] [Accepted: 11/23/2018] [Indexed: 11/23/2022]
Abstract
We describe an open-source automated multiwell plate fluorescence lifetime imaging (FLIM) methodology to read out Förster resonance energy transfer (FRET) between fluorescent proteins (FPs) labeling endogenous kinetochore proteins (KPs) in live budding yeast cells. The low copy number of many KPs and their small spatial extent present significant challenges for the quantification of donor fluorescence lifetime in the presence of significant cellular autofluorescence and photobleaching. Automated FLIM data acquisition was controlled by µManager and incorporated wide-field time-gated imaging with optical sectioning to reduce background fluorescence. For data analysis, we used custom MATLAB-based software tools to perform kinetochore foci segmentation and local cellular background subtraction and fitted the fluorescence lifetime data using the open-source FLIMfit software. We validated the methodology using endogenous KPs labeled with mTurquoise2 FP and/or yellow FP and measured the donor fluorescence lifetimes for foci comprising 32 kinetochores with KP copy numbers as low as ~2 per kinetochore under an average labeling efficiency of 50%. We observed changes of median donor lifetime ≥250 ps for KPs known to form dimers. Thus, this FLIM high-content analysis platform enables the screening of relatively low-copy-number endogenous protein-protein interactions at spatially confined macromolecular complexes.
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Affiliation(s)
- Wenjun Guo
- Photonics Group, Department of Physics,
Imperial College London, London, UK
- Francis Crick Institute, London,
UK
| | - Sunil Kumar
- Photonics Group, Department of Physics,
Imperial College London, London, UK
- Francis Crick Institute, London,
UK
| | - Frederik Görlitz
- Photonics Group, Department of Physics,
Imperial College London, London, UK
| | - Edwin Garcia
- Photonics Group, Department of Physics,
Imperial College London, London, UK
| | - Yuriy Alexandrov
- Photonics Group, Department of Physics,
Imperial College London, London, UK
- Francis Crick Institute, London,
UK
| | - Ian Munro
- Photonics Group, Department of Physics,
Imperial College London, London, UK
| | - Douglas J. Kelly
- Photonics Group, Department of Physics,
Imperial College London, London, UK
- RIKEN Center for Biodynamic Systems
Research, Kobe, Japan
| | - Sean Warren
- Garvan Institute of Medical Research,
University of New South Wales, Sydney, New South Wales, Australia
| | - Peter Thorpe
- Francis Crick Institute, London,
UK
- Queen Mary University of London, London,
UK
| | - Christopher Dunsby
- Photonics Group, Department of Physics,
Imperial College London, London, UK
- Francis Crick Institute, London,
UK
- Centre for Pathology, Imperial College
London, London, UK
| | - Paul French
- Photonics Group, Department of Physics,
Imperial College London, London, UK
- Francis Crick Institute, London,
UK
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5
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Stanoev A, Mhamane A, Schuermann KC, Grecco HE, Stallaert W, Baumdick M, Brüggemann Y, Joshi MS, Roda-Navarro P, Fengler S, Stockert R, Roßmannek L, Luig J, Koseska A, Bastiaens PIH. Interdependence between EGFR and Phosphatases Spatially Established by Vesicular Dynamics Generates a Growth Factor Sensing and Responding Network. Cell Syst 2018; 7:295-309.e11. [PMID: 30145116 PMCID: PMC6167251 DOI: 10.1016/j.cels.2018.06.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 12/22/2017] [Accepted: 06/07/2018] [Indexed: 12/20/2022]
Abstract
The proto-oncogenic epidermal growth factor receptor (EGFR) is a tyrosine kinase whose sensitivity to growth factors and signal duration determines cellular behavior. We resolve how EGFR's response to epidermal growth factor (EGF) originates from dynamically established recursive interactions with spatially organized protein tyrosine phosphatases (PTPs). Reciprocal genetic PTP perturbations enabled identification of receptor-like PTPRG/J at the plasma membrane and ER-associated PTPN2 as the major EGFR dephosphorylating activities. Imaging spatial-temporal PTP reactivity revealed that vesicular trafficking establishes a spatially distributed negative feedback with PTPN2 that determines signal duration. On the other hand, single-cell dose-response analysis uncovered a reactive oxygen species-mediated toggle switch between autocatalytically activated monomeric EGFR and the tumor suppressor PTPRG that governs EGFR's sensitivity to EGF. Vesicular recycling of monomeric EGFR unifies the interactions with these PTPs on distinct membrane systems, dynamically generating a network architecture that can sense and respond to time-varying growth factor signals.
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Affiliation(s)
- Angel Stanoev
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Amit Mhamane
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Klaus C Schuermann
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Hernán E Grecco
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Wayne Stallaert
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Martin Baumdick
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Yannick Brüggemann
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund, 44227 Dortmund, Germany
| | - Maitreyi S Joshi
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Pedro Roda-Navarro
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Sven Fengler
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Rabea Stockert
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Lisaweta Roßmannek
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Jutta Luig
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany
| | - Aneta Koseska
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund, 44227 Dortmund, Germany.
| | - Philippe I H Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, 44227 Dortmund, Germany; Faculty of Chemistry and Chemical Biology, TU Dortmund, 44227 Dortmund, Germany.
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6
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Baumdick M, Gelléri M, Uttamapinant C, Beránek V, Chin JW, Bastiaens PIH. A conformational sensor based on genetic code expansion reveals an autocatalytic component in EGFR activation. Nat Commun 2018; 9:3847. [PMID: 30242154 PMCID: PMC6155120 DOI: 10.1038/s41467-018-06299-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/10/2018] [Indexed: 12/26/2022] Open
Abstract
Epidermal growth factor receptor (EGFR) activation by growth factors (GFs) relies on dimerization and allosteric activation of its intrinsic kinase activity, resulting in trans-phosphorylation of tyrosines on its C-terminal tail. While structural and biochemical studies identified this EGF-induced allosteric activation, imaging collective EGFR activation in cells and molecular dynamics simulations pointed at additional catalytic EGFR activation mechanisms. To gain more insight into EGFR activation mechanisms in living cells, we develop a Förster resonance energy transfer (FRET)-based conformational EGFR indicator (CONEGI) using genetic code expansion that reports on conformational transitions in the EGFR activation loop. Comparing conformational transitions, self-association and auto-phosphorylation of CONEGI and its Y845F mutant reveals that Y845 phosphorylation induces a catalytically active conformation in EGFR monomers. This conformational transition depends on EGFR kinase activity and auto-phosphorylation on its C-terminal tail, generating a looped causality that leads to autocatalytic amplification of EGFR phosphorylation at low EGF dose. Upon ligand binding epidermal growth factor receptor (EGFR) dimerizes and activates its intrinsic kinase to auto-phosphorylate EGFR. Here, the authors engineer and image a FRET-based conformational EGFR indicator which reveals that activation loop phosphorylation induces a catalytically active conformation in EGFR monomers.
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Affiliation(s)
- Martin Baumdick
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Street 11, 44227, Dortmund, Germany
| | - Márton Gelléri
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Street 11, 44227, Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Street 6, 44227, Dortmund, Germany
| | - Chayasith Uttamapinant
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Václav Beránek
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Jason W Chin
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| | - Philippe I H Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Street 11, 44227, Dortmund, Germany. .,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Street 6, 44227, Dortmund, Germany.
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7
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Jeong S, Hermsmeier M, Osseiran S, Yamamoto A, Nagavarapu U, Chan KF, Evans CL. Visualization of drug distribution of a topical minocycline gel in human facial skin. BIOMEDICAL OPTICS EXPRESS 2018; 9:3434-3448. [PMID: 29984108 PMCID: PMC6033575 DOI: 10.1364/boe.9.003434] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/24/2018] [Accepted: 06/02/2018] [Indexed: 05/21/2023]
Abstract
Acne vulgaris is a common chronic skin disease in young adults caused by infection of the pilosebaceous unit, resulting in pimples and possibly permanent scarring on the skin. Minocycline, a common antibiotic, has been widely utilized as a systemic antimicrobial treatment for acne via oral administration. Recently, a topical minocycline gel (BPX-01) was developed to directly deliver minocycline through the epidermis and into the pilosebaceous unit to achieve localized treatment with lower doses of drug. As the effectiveness of the drug is directly related to its successful delivery, there is a need to evaluate the pharmacokinetics at the cellular level within tissue. Advantageously, minocycline is naturally fluorescent and can be directly visualized using microscopy-based approaches. Due to high endogenous autofluorescence, however, imaging of weakly emitting fluorescent molecules such as minocycline in skin tissue can be challenging. Here, we demonstrate a method for the selective visualization of minocycline within human skin tissue by utilizing two-photon excitation fluorescence (TPEF) microscopy and fluorescence lifetime imaging microscopy (FLIM). To demonstrate the feasibility of this approach, ex vivo human facial skin samples treated with various concentrations of BPX-01 were investigated. From the TPEF analysis, we were able to visualize relatively high levels of drug uptake within facial skin. However, minocycline fluorescence could be overwhelmed by endogenous fluorescence that complicates TPEF quantitative analysis, making FLIM more advantageous for visualizing drug uptake. Importantly, we found a unique signature of minocycline uptake via FLIM analysis that enabled the successful differentiation of the drug and enabled the extraction of drug local distribution from the endogenous fluorescence using a non-Euclidean phasor analysis method. Based on these results, we believe that the drug local distribution visualization method using TPEF and FLIM with phasor analysis can play an important role in studying the pharmacokinetics and pharmacodynamics of a topically applicable drug.
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Affiliation(s)
- Sinyoung Jeong
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Maiko Hermsmeier
- BioPharmX, Inc., 1505 Adams Drive, Suite D, Menlo Park, CA 94025, USA
| | - Sam Osseiran
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
- Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Avenue E25-519, Cambridge, MA 02139, USA
| | - Akira Yamamoto
- BioPharmX, Inc., 1505 Adams Drive, Suite D, Menlo Park, CA 94025, USA
| | - Usha Nagavarapu
- BioPharmX, Inc., 1505 Adams Drive, Suite D, Menlo Park, CA 94025, USA
| | - Kin F. Chan
- BioPharmX, Inc., 1505 Adams Drive, Suite D, Menlo Park, CA 94025, USA
| | - Conor L. Evans
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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8
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Alexandrov Y, Nikolic DS, Dunsby C, French PMW. Quantitative time domain analysis of lifetime-based Förster resonant energy transfer measurements with fluorescent proteins: Static random isotropic fluorophore orientation distributions. JOURNAL OF BIOPHOTONICS 2018; 11:e201700366. [PMID: 29582566 DOI: 10.1002/jbio.201700366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/23/2018] [Indexed: 06/08/2023]
Abstract
Förster resonant energy transfer (FRET) measurements are widely used to obtain information about molecular interactions and conformations through the dependence of FRET efficiency on the proximity of donor and acceptor fluorophores. Fluorescence lifetime measurements can provide quantitative analysis of FRET efficiency and interacting population fraction. Many FRET experiments exploit the highly specific labelling of genetically expressed fluorescent proteins, applicable in live cells and organisms. Unfortunately, the typical assumption of fast randomization of fluorophore orientations in the analysis of fluorescence lifetime-based FRET readouts is not valid for fluorescent proteins due to their slow rotational mobility compared to their upper state lifetime. Here, previous analysis of effectively static isotropic distributions of fluorophore dipoles on FRET measurements is incorporated into new software for fitting donor emission decay profiles. Calculated FRET parameters, including molar population fractions, are compared for the analysis of simulated and experimental FRET data under the assumption of static and dynamic fluorophores and the intermediate regimes between fully dynamic and static fluorophores, and mixtures within FRET pairs, is explored. Finally, a method to correct the artefact resulting from fitting the emission from static FRET pairs with isotropic angular distributions to the (incorrect) typically assumed dynamic FRET decay model is presented.
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Affiliation(s)
- Yuriy Alexandrov
- Photonics Group, Department of Physics, Imperial College London, London, UK
- Light Microscopy, Francis Crick Institute, London, UK
| | - Dino S Nikolic
- Quantum Physics and Information Technology Group, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Christopher Dunsby
- Photonics Group, Department of Physics, Imperial College London, London, UK
- Light Microscopy, Francis Crick Institute, London, UK
- Centre for Pathology, Imperial College London, London, UK
| | - Paul M W French
- Photonics Group, Department of Physics, Imperial College London, London, UK
- Light Microscopy, Francis Crick Institute, London, UK
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9
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Accurate phosphorylation site localization using phospho-brackets. Anal Chim Acta 2017; 996:38-47. [PMID: 29137706 DOI: 10.1016/j.aca.2017.09.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/27/2017] [Accepted: 09/28/2017] [Indexed: 11/21/2022]
Abstract
Phosphorylation is one of the most important and widely studied protein post-translational modifications. Tandem mass spectrometry using higher-energy collisional dissociation has evolved into a state-of-the-art analytical platform for both phosphorylation identification and site localization. Tens of thousands of phosphopeptides can now be routinely identified from a single shotgun proteomics study; site localization, however, is much more complicated and many challenges still exist. Here, we report our development of P-bracket using direct experimental evidence of phospho-containing site-determining product ions for accurate site localization without the need for additional FLR control. A P-bracket is defined as a complementary product ion pair that forms a bracket to confine a phosphorylation event to a unique site. P-bracket has been successfully benchmarked with a set of six synthetic phosphopeptides with a single phosphorylation event, a set of 96 synthetic peptides and phosphopeptide reference libraries, and two HeLa phosphopeptide LC-MS/MS (HCD) datasets; Accurate phosphosite localization by P-bracket will greatly enhance identification confidence of phosphopeptides and contribute to structural and functional studies of phosphoproteins.
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10
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Spatial cycles mediated by UNC119 solubilisation maintain Src family kinases plasma membrane localisation. Nat Commun 2017; 8:114. [PMID: 28740133 PMCID: PMC5524651 DOI: 10.1038/s41467-017-00116-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 06/02/2017] [Indexed: 12/12/2022] Open
Abstract
The peripheral membrane proto-oncogene Src family protein tyrosine kinases relay growth factor signals to the cytoplasm of mammalian cells. We unravel the spatial cycles of solubilisation, trapping on perinuclear membrane compartments and vesicular transport that counter entropic equilibration to endomembranes for maintaining the enrichment and activity of Src family protein tyrosine kinases at the plasma membrane. The solubilising factor UNC119 sequesters myristoylated Src family protein tyrosine kinases from the cytoplasm, enhancing their diffusion to effectively release Src family protein tyrosine kinases on the recycling endosome by localised Arl2/3 activity. Src is then trapped on the recycling endosome via electrostatic interactions, whereas Fyn is quickly released to be kinetically trapped on the Golgi by palmitoyl acyl-transferase activity. Vesicular trafficking from these compartments restores enrichment of the Src family protein tyrosine kinases to the plasma membrane. Interference with these spatial cycles by UNC119 knockdown disrupts Src family protein tyrosine kinase localisation and signalling activity, indicating that UNC119 could be a drug target to affect oncogenic Src family protein tyrosine kinase signalling. The peripheral membrane proto-oncogene Src family protein tyrosine kinases (SFKs) transmit growth factor signals to the cytoplasm. Here the authors show that the solubilising factor UNC119 sequesters myristoylated SFKs to maintain its enrichment at the plasma membrane to enable signal transduction.
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11
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Silberberg M, Grecco HE. pawFLIM: reducing bias and uncertainty to enable lower photon count in FLIM experiments. Methods Appl Fluoresc 2017. [DOI: 10.1088/2050-6120/aa72ab] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Liu HT, Lin WL, Feng YL, Lin Y, Chen YC. Multidie LED combined with homogenizing optics to improve frequency response and intensity for FLIM applications. J Microsc 2017; 266:324-334. [PMID: 28294329 DOI: 10.1111/jmi.12541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/19/2017] [Accepted: 01/25/2017] [Indexed: 11/28/2022]
Abstract
Application of light-emitting diodes (LEDs) in frequency-domain fluorescence lifetime imaging microscopy (FLIM) has been limited by the trade-off between modulation frequency and illumination intensity of LEDs, which affects the signal-to-noise ratio in fluorescence lifetime measurements. To increase modulation frequency without sacrificing output power of LEDs, we propose to use LEDs with multiple dice connected in series. The LED capacitance was reduced with series connection; therefore, the frequency response of multidie LED was significantly increased. LEDs in visible light, including blue, green, amber and red, were all applicable in FLIM. We also present a homogenizing optics design, so that multidie LEDs produced uniform illumination on the same focal spot. When the homogenizing optics was combined with multicolour emitters, it provides multiple colour selection in a compact and convenient design.
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Affiliation(s)
- H-T Liu
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan, Taiwan
| | - W-L Lin
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan, Taiwan
| | - Y-L Feng
- Institute of Photonic System, National Chiao Tung University, Tainan, Taiwan
| | - Y Lin
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan, Taiwan
| | - Y-C Chen
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan, Taiwan
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13
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Martín-Gago P, Fansa EK, Klein CH, Murarka S, Janning P, Schürmann M, Metz M, Ismail S, Schultz-Fademrecht C, Baumann M, Bastiaens PIH, Wittinghofer A, Waldmann H. A PDE6δ-KRas Inhibitor Chemotype with up to Seven H-Bonds and Picomolar Affinity that Prevents Efficient Inhibitor Release by Arl2. Angew Chem Int Ed Engl 2017; 56:2423-2428. [PMID: 28106325 DOI: 10.1002/anie.201610957] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Indexed: 12/11/2022]
Abstract
Small-molecule inhibition of the interaction between the KRas oncoprotein and the chaperone PDE6δ impairs KRas spatial organization and signaling in cells. However, despite potent binding in vitro (KD <10 nm), interference with Ras signaling and growth inhibition require 5-20 μm compound concentrations. We demonstrate that these findings can be explained by fast release of high-affinity inhibitors from PDE6δ by the release factor Arl2. This limitation is overcome by novel highly selective inhibitors that bind to PDE6δ with up to 7 hydrogen bonds, resulting in picomolar affinity. Their release by Arl2 is greatly decreased, and representative compounds selectively inhibit growth of KRas mutated and -dependent cells with the highest activity recorded yet. Our findings indicate that very potent inhibitors of the KRas-PDE6δ interaction may impair the growth of tumors driven by oncogenic KRas.
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Affiliation(s)
- Pablo Martín-Gago
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
| | - Eyad K Fansa
- Structural Biology Group, Max Planck Institute for Molecular Physiology, 44227, Dortmund, Germany
| | - Christian H Klein
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
| | - Sandip Murarka
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
| | - Petra Janning
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
| | - Marc Schürmann
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
| | - Malte Metz
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
| | - Shehab Ismail
- Structural Biology Group, Max Planck Institute for Molecular Physiology, 44227, Dortmund, Germany
| | | | | | - Philippe I H Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
- TU Dortmund, Faculty of Chemistry and Chemical Biology, 44227, Dortmund, Germany
| | - Alfred Wittinghofer
- Structural Biology Group, Max Planck Institute for Molecular Physiology, 44227, Dortmund, Germany
| | - Herbert Waldmann
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, 44227, Dortmund, Germany
- TU Dortmund, Faculty of Chemistry and Chemical Biology, 44227, Dortmund, Germany
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14
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Martín-Gago P, Fansa EK, Klein CH, Murarka S, Janning P, Schürmann M, Metz M, Ismail S, Schultz-Fademrecht C, Baumann M, Bastiaens PIH, Wittinghofer A, Waldmann H. A PDE6δ-KRas Inhibitor Chemotype with up to Seven H-Bonds and Picomolar Affinity that Prevents Efficient Inhibitor Release by Arl2. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201610957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Pablo Martín-Gago
- Department of Chemical Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
| | - Eyad K. Fansa
- Structural Biology Group; Max Planck Institute for Molecular Physiology; 44227 Dortmund Germany
| | - Christian H. Klein
- Department of Systemic Cell Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
| | - Sandip Murarka
- Department of Chemical Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
| | - Petra Janning
- Department of Chemical Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
| | - Marc Schürmann
- Department of Chemical Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
| | - Malte Metz
- Department of Chemical Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
| | - Shehab Ismail
- Structural Biology Group; Max Planck Institute for Molecular Physiology; 44227 Dortmund Germany
| | | | | | - Philippe I. H. Bastiaens
- Department of Systemic Cell Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
- TU Dortmund; Faculty of Chemistry and Chemical Biology; 44227 Dortmund Germany
| | - Alfred Wittinghofer
- Structural Biology Group; Max Planck Institute for Molecular Physiology; 44227 Dortmund Germany
| | - Herbert Waldmann
- Department of Chemical Biology; Max Planck Institute of Molecular Physiology; 44227 Dortmund Germany
- TU Dortmund; Faculty of Chemistry and Chemical Biology; 44227 Dortmund Germany
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15
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Görlitz F, Kelly DJ, Warren SC, Alibhai D, West L, Kumar S, Alexandrov Y, Munro I, Garcia E, McGinty J, Talbot C, Serwa RA, Thinon E, da Paola V, Murray EJ, Stuhmeier F, Neil MAA, Tate EW, Dunsby C, French PMW. Open Source High Content Analysis Utilizing Automated Fluorescence Lifetime Imaging Microscopy. J Vis Exp 2017:55119. [PMID: 28190060 PMCID: PMC5352269 DOI: 10.3791/55119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We present an open source high content analysis instrument utilizing automated fluorescence lifetime imaging (FLIM) for assaying protein interactions using Förster resonance energy transfer (FRET) based readouts of fixed or live cells in multiwell plates. This provides a means to screen for cell signaling processes read out using intramolecular FRET biosensors or intermolecular FRET of protein interactions such as oligomerization or heterodimerization, which can be used to identify binding partners. We describe here the functionality of this automated multiwell plate FLIM instrumentation and present exemplar data from our studies of HIV Gag protein oligomerization and a time course of a FRET biosensor in live cells. A detailed description of the practical implementation is then provided with reference to a list of hardware components and a description of the open source data acquisition software written in µManager. The application of FLIMfit, an open source MATLAB-based client for the OMERO platform, to analyze arrays of multiwell plate FLIM data is also presented. The protocols for imaging fixed and live cells are outlined and a demonstration of an automated multiwell plate FLIM experiment using cells expressing fluorescent protein-based FRET constructs is presented. This is complemented by a walk-through of the data analysis for this specific FLIM FRET data set.
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Affiliation(s)
- Frederik Görlitz
- Photonics Group, Department of Physics, Imperial College London;
| | - Douglas J Kelly
- Photonics Group, Department of Physics, Imperial College London
| | - Sean C Warren
- Photonics Group, Department of Physics, Imperial College London
| | - Dominic Alibhai
- Institute for Chemical Biology, Department of Chemistry, Imperial College London
| | - Lucien West
- MRC Clinical Sciences Centre, Hammersmith Hospital
| | - Sunil Kumar
- Photonics Group, Department of Physics, Imperial College London
| | | | - Ian Munro
- Photonics Group, Department of Physics, Imperial College London
| | - Edwin Garcia
- Photonics Group, Department of Physics, Imperial College London
| | - James McGinty
- Photonics Group, Department of Physics, Imperial College London
| | - Clifford Talbot
- Photonics Group, Department of Physics, Imperial College London
| | - Remigiusz A Serwa
- Chemical Biology Section, Department of Chemistry, Imperial College London
| | - Emmanuelle Thinon
- Chemical Biology Section, Department of Chemistry, Imperial College London
| | | | | | - Frank Stuhmeier
- Pfizer Global Research and Development, Pfizer Limited, Sandwich, Kent, UK
| | - Mark A A Neil
- Photonics Group, Department of Physics, Imperial College London
| | - Edward W Tate
- Chemical Biology Section, Department of Chemistry, Imperial College London
| | - Christopher Dunsby
- Photonics Group, Department of Physics, Imperial College London; Centre for Histopathology, Imperial College London
| | - Paul M W French
- Photonics Group, Department of Physics, Imperial College London
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16
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Kuchenov D, Laketa V, Stein F, Salopiata F, Klingmüller U, Schultz C. High-Content Imaging Platform for Profiling Intracellular Signaling Network Activity in Living Cells. Cell Chem Biol 2016; 23:1550-1559. [PMID: 27939899 PMCID: PMC5193178 DOI: 10.1016/j.chembiol.2016.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/19/2016] [Accepted: 11/14/2016] [Indexed: 01/06/2023]
Abstract
Essential characteristics of cellular signaling networks include a complex interconnected architecture and temporal dynamics of protein activity. The latter can be monitored by Förster resonance energy transfer (FRET) biosensors at a single-live-cell level with high temporal resolution. However, these experiments are typically limited to the use of a couple of FRET biosensors. Here, we describe a FRET-based multi-parameter imaging platform (FMIP) that allows simultaneous high-throughput monitoring of multiple signaling pathways. We apply FMIP to monitor the crosstalk between epidermal growth factor receptor (EGFR) and insulin-like growth factor-1 receptor signaling, signaling perturbations caused by pathophysiologically relevant EGFR mutations, and the effects of a clinically important MEK inhibitor (selumetinib) on the EGFR network. We expect that in the future the platform will be applied to develop comprehensive models of signaling networks and will help to investigate the mechanism of action as well as side effects of therapeutic treatments.
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Affiliation(s)
- Dmitry Kuchenov
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Vibor Laketa
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Frank Stein
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Florian Salopiata
- Division of Systems Biology of Signal Transduction, Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), 69120 Heidelberg, Germany
| | - Ursula Klingmüller
- Division of Systems Biology of Signal Transduction, Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), 69120 Heidelberg, Germany
| | - Carsten Schultz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany; Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), 69120 Heidelberg, Germany; Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97201, USA.
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17
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Korhonen EA, Lampinen A, Giri H, Anisimov A, Kim M, Allen B, Fang S, D'Amico G, Sipilä TJ, Lohela M, Strandin T, Vaheri A, Ylä-Herttuala S, Koh GY, McDonald DM, Alitalo K, Saharinen P. Tie1 controls angiopoietin function in vascular remodeling and inflammation. J Clin Invest 2016; 126:3495-510. [PMID: 27548530 DOI: 10.1172/jci84923] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 06/24/2016] [Indexed: 12/11/2022] Open
Abstract
The angiopoietin/Tie (ANG/Tie) receptor system controls developmental and tumor angiogenesis, inflammatory vascular remodeling, and vessel leakage. ANG1 is a Tie2 agonist that promotes vascular stabilization in inflammation and sepsis, whereas ANG2 is a context-dependent Tie2 agonist or antagonist. A limited understanding of ANG signaling mechanisms and the orphan receptor Tie1 has hindered development of ANG/Tie-targeted therapeutics. Here, we determined that both ANG1 and ANG2 binding to Tie2 increases Tie1-Tie2 interactions in a β1 integrin-dependent manner and that Tie1 regulates ANG-induced Tie2 trafficking in endothelial cells. Endothelial Tie1 was essential for the agonist activity of ANG1 and autocrine ANG2. Deletion of endothelial Tie1 in mice reduced Tie2 phosphorylation and downstream Akt activation, increased FOXO1 nuclear localization and transcriptional activation, and prevented ANG1- and ANG2-induced capillary-to-venous remodeling. However, in acute endotoxemia, the Tie1 ectodomain that is responsible for interaction with Tie2 was rapidly cleaved, ANG1 agonist activity was decreased, and autocrine ANG2 agonist activity was lost, which led to suppression of Tie2 signaling. Tie1 cleavage also occurred in patients with hantavirus infection. These results support a model in which Tie1 directly interacts with Tie2 to promote ANG-induced vascular responses under noninflammatory conditions, whereas in inflammation, Tie1 cleavage contributes to loss of ANG2 agonist activity and vascular stability.
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18
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Multiplexed imaging of intracellular protein networks. Cytometry A 2016; 89:761-75. [DOI: 10.1002/cyto.a.22876] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 04/21/2016] [Accepted: 04/26/2016] [Indexed: 12/19/2022]
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19
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Protein-specific imaging of posttranslational modifications. Curr Opin Chem Biol 2015; 28:156-63. [DOI: 10.1016/j.cbpa.2015.07.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/23/2015] [Accepted: 07/27/2015] [Indexed: 11/18/2022]
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20
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Roda-Navarro P, Bastiaens PI. Dynamic recruitment of protein tyrosine phosphatase PTPD1 to EGF stimulation sites potentiates EGFR activation. PLoS One 2014; 9:e103203. [PMID: 25062045 PMCID: PMC4111557 DOI: 10.1371/journal.pone.0103203] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/26/2014] [Indexed: 11/25/2022] Open
Abstract
Balanced activity of protein tyrosine kinases and phosphatases (PTPs) controls tyrosine phosphorylation levels and, consequently, is needed to prevent pathologies like cancer. Phosphatase activity is tightly regulated in space and time. Thus, in order to understand how phospho-tyrosine signalling is regulated, the intracellular dynamics of PTPs should be investigated. Here, we have studied the intracellular dynamics of PTPD1, a FERM (four-point-one, ezrin, radixin, moesin) domain-containing PTP that is over expressed in cancer cells and potentiates EGFR signalling. Whereas PTPD1 was excluded from E-cadherin rich cell-cell adhesions in epithelial cell monolayers, it diffused from the cytoplasm to those membranes in contact with the extracellular medium. Localisation of PTPD1 at the plasma membrane was mediated by its FERM domain and enabled the formation of EGFR/PTPD1-containing signalling complexes that pre-existed at the plasma membrane before EGF stimulation. PTPD1 and EGFR transiently co-localised at EGF stimulation sites until the formation of macropinosomes containing active species of EGFR. Interference of PTPD1 expression caused a decrease in EGFR phosphorylated species at the periphery of the cell. Presented data suggest that the transient formation of dynamic PTPD1/EGFR signalling complexes strengthens EGF signalling by promoting the spatial propagation of EGFR phosphorylated species.
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Affiliation(s)
- Pedro Roda-Navarro
- Department of Immunology, School of Medicine, Complutense University and ‘12 de Octubre’ Health Research Institute, Madrid, Spain
- * E-mail: (PR-N); (PIB)
| | - Philippe I. Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
- * E-mail: (PR-N); (PIB)
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21
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Conway JRW, Carragher NO, Timpson P. Developments in preclinical cancer imaging: innovating the discovery of therapeutics. Nat Rev Cancer 2014; 14:314-28. [PMID: 24739578 DOI: 10.1038/nrc3724] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Integrating biological imaging into early stages of the drug discovery process can provide invaluable readouts of drug activity within complex disease settings, such as cancer. Iterating this approach from initial lead compound identification in vitro to proof-of-principle in vivo analysis represents a key challenge in the drug discovery field. By embracing more complex and informative models in drug discovery, imaging can improve the fidelity and statistical robustness of preclinical cancer studies. In this Review, we highlight how combining advanced imaging with three-dimensional systems and intravital mouse models can provide more informative and disease-relevant platforms for cancer drug discovery.
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Affiliation(s)
- James R W Conway
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre Sydney, St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, New South Wales 2010, Sydney, Australia
| | - Neil O Carragher
- Edinburgh Cancer Research UK Centre, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, EH4 2XR, UK
| | - Paul Timpson
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre Sydney, St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, New South Wales 2010, Sydney, Australia
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22
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Arndt-Jovin DJ, Botelho MG, Jovin TM. Structure-function relationships of ErbB RTKs in the plasma membrane of living cells. Cold Spring Harb Perspect Biol 2014; 6:a008961. [PMID: 24691959 DOI: 10.1101/cshperspect.a008961] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We review the states of the ErbB family of receptor tyrosine kinases (RTKs), primarily the EGF receptor (EGFR, ErbB1, HER1) and the orphan receptor ErbB2 as they exist in living mammalian cells, focusing on four main aspects: (1) aggregation state and distribution in the plasma membrane; (2) conformational features of the receptors situated in the plasma membrane, compared to the crystallographic structures of the isolated extracellular domains; (3) coupling of receptor disposition on filopodia with the transduction of signaling ligand gradients; and (4) ligand-independent receptor activation by application of a magnetic field.
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Affiliation(s)
- Donna J Arndt-Jovin
- Laboratory of Cellular Dynamics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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23
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Szmacinski H, Toshchakov V, Lakowicz JR. Application of phasor plot and autofluorescence correction for study of heterogeneous cell population. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:046017. [PMID: 24770662 PMCID: PMC4000004 DOI: 10.1117/1.jbo.19.4.046017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 03/09/2014] [Accepted: 03/25/2014] [Indexed: 05/22/2023]
Abstract
Protein-protein interactions in cells are often studied using fluorescence resonance energy transfer (FRET) phenomenon by fluorescence lifetime imaging microscopy (FLIM). Here, we demonstrate approaches to the quantitative analysis of FRET in cell population in a case complicated by a highly heterogeneous donor expression, multiexponential donor lifetime, large contribution of cell autofluorescence, and significant presence of unquenched donor molecules that do not interact with the acceptor due to low affinity of donor-acceptor binding. We applied a multifrequency phasor plot to visualize FRET FLIM data, developed a method for lifetime background correction, and performed a detailed time-resolved analysis using a biexponential model. These approaches were applied to study the interaction between the Toll Interleukin-1 receptor (TIR) domain of Toll-like receptor 4 (TLR4) and the decoy peptide 4BB. TLR4 was fused to Cerulean fluorescent protein (Cer) and 4BB peptide was labeled with Bodipy TMRX (BTX). Phasor displays for multifrequency FLIM data are presented. The analytical procedure for lifetime background correction is described and the effect of correction on FLIM data is demonstrated. The absolute FRET efficiency was determined based on the phasor plot display and multifrequency FLIM data analysis. The binding affinity between TLR4-Cer (donor) and decoy peptide 4BB-BTX (acceptor) was estimated in a heterogeneous HeLa cell population.
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Affiliation(s)
- Henryk Szmacinski
- University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, Baltimore, Maryland 21201
- Address all correspondence to: Henryk Szmacinski, E-mail:
| | - Vladimir Toshchakov
- University of Maryland School of Medicine, Department of Microbiology and Immunology, Baltimore, Maryland 21201
| | - Joseph R. Lakowicz
- University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, Baltimore, Maryland 21201
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24
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Quantification and kinetic analysis of Grb2-EGFR interaction on micro-patterned surfaces for the characterization of EGFR-modulating substances. PLoS One 2014; 9:e92151. [PMID: 24658383 PMCID: PMC3962377 DOI: 10.1371/journal.pone.0092151] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 02/17/2014] [Indexed: 11/25/2022] Open
Abstract
The identification of the epidermal growth factor receptor (EGFR) as an oncogene has led to the development of several anticancer therapeutics directed against this receptor tyrosine kinase. However, drug resistance and low efficacy remain a severe challenge, and have led to a demand for novel systems for an efficient identification and characterization of new substances. Here we report on a technique which combines micro-patterned surfaces and total internal reflection fluorescence (TIRF) microscopy (μ-patterning assay) for the quantitative analysis of EGFR activity. It does not simply measure the phosphorylation of the receptor, but instead quantifies the interaction of the key signal transmitting protein Grb2 (growth factor receptor-bound protein 2) with the EGFR in a live cell context. It was possible to demonstrate an EGF dependent recruitment of Grb2 to the EGFR, which was significantly inhibited in the presence of clinically tested EGFR inhibitors, including small tyrosine kinase inhibitors and monoclonal antibodies targeting the EGF binding site. Importantly, in addition to its potential use as a screening tool, our experimental setup offers the possibility to provide insight into the molecular mechanisms of bait-prey interaction. Recruitment of the EGFR together with Grb2 to clathrin coated pits (CCPs) was found to be a key feature in our assay. Application of bleaching experiments enabled calculation of the Grb2 exchange rate, which significantly changed upon stimulation or the presence of EGFR activity inhibiting drugs.
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25
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Nobis M, McGhee EJ, Herrmann D, Magenau A, Morton JP, Anderson KI, Timpson P. Monitoring the dynamics of Src activity in response to anti-invasive dasatinib treatment at a subcellular level using dual intravital imaging. Cell Adh Migr 2014; 8:478-86. [PMID: 25482620 PMCID: PMC4594577 DOI: 10.4161/19336918.2014.970004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 10/20/2014] [Accepted: 07/24/2014] [Indexed: 12/18/2022] Open
Abstract
Optimising response to tyrosine kinase inhibitors in cancer remains an extensive field of research. Intravital imaging is an emerging tool, which can be used in drug discovery to facilitate and fine-tune maximum drug response in live tumors. A greater understanding of intratumoural delivery and pharmacodynamics of a drug can be obtained by imaging drug target-specific fluorescence resonance energy transfer (FRET) biosensors in real time. Here, we outline our recent work using a Src-FRET biosensor as a readout of Src activity to gauge optimal tyrosine kinase inhibition in response to dasatinib treatment regimens in vivo. By simultaneously monitoring both the inhibition of Src using FRET imaging, and the modulation of the surrounding extracellular matrix using second harmonic generation (SHG) imaging, we were able to show enhanced drug penetrance and delivery to live pancreatic tumors. We discuss the implications of this dual intravital imaging approach in the context of altered tumor-stromal interactions, while summarising how this approach could be applied to assess other combination strategies or tyrosine kinase inhibitors in a preclinical setting.
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Affiliation(s)
- Max Nobis
- The Beatson Institute for Cancer Research; Garscube Estate; Glasgow, UK
| | - Ewan J McGhee
- The Beatson Institute for Cancer Research; Garscube Estate; Glasgow, UK
| | - David Herrmann
- The Garvan Institute of Medical Research and The Kinghorn Cancer Centre; Cancer Division; St. Vincent's Clinical School; Faculty of Medicine; University of New South Wales; Sydney, Australia
| | - Astrid Magenau
- The Garvan Institute of Medical Research and The Kinghorn Cancer Centre; Cancer Division; St. Vincent's Clinical School; Faculty of Medicine; University of New South Wales; Sydney, Australia
| | - Jennifer P Morton
- The Beatson Institute for Cancer Research; Garscube Estate; Glasgow, UK
| | - Kurt I Anderson
- The Beatson Institute for Cancer Research; Garscube Estate; Glasgow, UK
| | - Paul Timpson
- The Garvan Institute of Medical Research and The Kinghorn Cancer Centre; Cancer Division; St. Vincent's Clinical School; Faculty of Medicine; University of New South Wales; Sydney, Australia
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26
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Mérola F, Fredj A, Betolngar DB, Ziegler C, Erard M, Pasquier H. Newly engineered cyan fluorescent proteins with enhanced performances for live cell FRET imaging. Biotechnol J 2013; 9:180-91. [DOI: 10.1002/biot.201300198] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 09/17/2013] [Accepted: 10/31/2013] [Indexed: 11/06/2022]
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27
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Nobis M, Carragher NO, McGhee EJ, Morton JP, Sansom OJ, Anderson KI, Timpson P. Advanced intravital subcellular imaging reveals vital three-dimensional signalling events driving cancer cell behaviour and drug responses in live tissue. FEBS J 2013; 280:5177-97. [PMID: 23678945 DOI: 10.1111/febs.12348] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/13/2013] [Accepted: 05/14/2013] [Indexed: 12/18/2022]
Abstract
The integration of signal transduction pathways plays a fundamental role in governing disease initiation, progression and outcome. It is therefore necessary to understand disease at the signalling level to enable effective treatment and to intervene in its progression. The recent extension of in vitro subcellular image-based analysis to live in vivo modelling of disease is providing a more complete picture of real-time, dynamic signalling processes or drug responses in live tissue. Intravital imaging offers alternative strategies for studying disease and embraces the biological complexities that govern disease progression. In the present review, we highlight how three-dimensional or live intravital imaging has uncovered novel insights into biological mechanisms or modes of drug action. Furthermore, we offer a prospective view of how imaging applications may be integrated further with the aim of understanding disease in a more physiological and functional manner within the framework of the drug discovery process.
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Affiliation(s)
- Max Nobis
- The Beatson Institute for Cancer Research, Glasgow, UK
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28
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Zhao L, Abe K, Barroso M, Intes X. Active wide-field illumination for high-throughput fluorescence lifetime imaging. OPTICS LETTERS 2013; 38:3976-9. [PMID: 24081103 PMCID: PMC3933959 DOI: 10.1364/ol.38.003976] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Wide-field fluorescence lifetime imaging allows for fast imaging of large sample areas at the cost of low sensitivity to weak fluorescence signals. To overcome this challenge, we developed an active wide-field illumination (AWFI) strategy to optimize the impinging spatial intensity for acquiring optimal fluorescence signals over the whole sample. We demonstrated the ability of AWFI to accurately estimate lifetimes from a multiwell plate sample with concentrations ranging over two orders of magnitude. We further reported its successful application to a quantitative Förster resonance energy transfer lifetime cell-based assay. Overall, this method allows for enhanced accuracy in lifetime-based imaging at high acquisition speed over samples with large fluorescence intensity distributions.
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Affiliation(s)
- Lingling Zhao
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Ken Abe
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Avenue, Albany, New York 12208, USA
| | - Margarida Barroso
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Avenue, Albany, New York 12208, USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
- Corresponding author:
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Grecco HE, Bastiaens PIH. Quantifying cellular dynamics by fluorescence resonance energy transfer (FRET) microscopy. ACTA ACUST UNITED AC 2013; Chapter 5:Unit5.22. [PMID: 23559306 DOI: 10.1002/0471142301.ns0522s63] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The cell is a spatially organized system whose function emerges from the complex interaction of molecular components. Such local interaction of nanometer-sized molecules generates patterns that span throughout the cell. Those patterns, in turn, regulate the molecular interactions. Understanding such simultaneous bidirectional causation requires quantifying the spatio-temporal progression of biochemical reactions in the context of a living cell. Due to its ability to resolve micrometer-sized structures, biological microscopy has been instrumental to the discovery and understanding of living systems. Functional fluorescence microscopy allows a cellular dynamic topographic map of proteins to be overlaid with topological information on the causality that determines protein state. Here we describe how Förster/fluorescence resonance energy transfer (FRET) can be used to measure the phosphorylation state of proteins in the context of the cell.
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Affiliation(s)
- Hernán E Grecco
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
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Nobis M, McGhee EJ, Morton JP, Schwarz JP, Karim SA, Quinn J, Edward M, Campbell AD, McGarry LC, Evans TRJ, Brunton VG, Frame MC, Carragher NO, Wang Y, Sansom OJ, Timpson P, Anderson KI. Intravital FLIM-FRET imaging reveals dasatinib-induced spatial control of src in pancreatic cancer. Cancer Res 2013; 73:4674-86. [PMID: 23749641 DOI: 10.1158/0008-5472.can-12-4545] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cancer invasion and metastasis occur in a complex three-dimensional (3D) environment, with reciprocal feedback from the surrounding host tissue and vasculature-governing behavior. In this study, we used a novel intravital method that revealed spatiotemporal regulation of Src activity in response to the anti-invasive Src inhibitor dasatinib. A fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer (FLIM-FRET) Src biosensor was used to monitor drug-targeting efficacy in a transgenic p53-mutant mouse model of pancreatic cancer. In contrast to conventional techniques, FLIM-FRET analysis allowed for accurate, time-dependent, live monitoring of drug efficacy and clearance in live tumors. In 3D organotypic cultures, we showed that a spatially distinct gradient of Src activity exists within invading tumor cells, governed by the depth of penetration into complex matrices. In parallel, this gradient was also found to exist within live tumors, where Src activity is enhanced at the invasive border relative to the tumor cortex. Upon treatment with dasatinib, we observed a switch in activity at the invasive borders, correlating with impaired metastatic capacity in vivo. Src regulation was governed by the proximity of cells to the host vasculature, as cells distal to the vasculature were regulated differentially in response to drug treatment compared with cells proximal to the vasculature. Overall, our results in live tumors revealed that a threshold of drug penetrance exists in vivo and that this can be used to map areas of poor drug-targeting efficiency within specific tumor microenvironments. We propose that using FLIM-FRET in this capacity could provide a useful preclinical tool in animal models before clinical translation.
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Affiliation(s)
- Max Nobis
- The Beatson Institute for Cancer Research, Glasgow; Section of Dermatology, School of Medicine, University of Glasgow, Glasgow, UK
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31
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Kozer N, Barua D, Orchard S, Nice EC, Burgess AW, Hlavacek WS, Clayton AH. Exploring higher-order EGFR oligomerisation and phosphorylation--a combined experimental and theoretical approach. MOLECULAR BIOSYSTEMS 2013; 9:1849-63. [PMID: 23629589 PMCID: PMC3698845 DOI: 10.1039/c3mb70073a] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The epidermal growth factor receptor (EGFR) kinase is generally considered to be activated by either ligand-induced dimerisation or a ligand-induced conformational change within pre-formed dimers. Ligand-induced higher-order EGFR oligomerisation or clustering has been reported but it is not clear how EGFR oligomers, as distinct from EGFR dimers, influence signaling outputs. To address this question, we combined measures of receptor clustering (microscopy; image correlation spectroscopy) and phosphorylation (Western blots) with modelling of mass-action chemical kinetics. A stable BaF/3 cell-line that contains a high proportion (>90%) of inactive dimers of EGFR-eGFP but no secreted ligand and no other detectable ErbB receptors was used as the model cell system. EGF at concentrations of greater than 1 nM was found to cluster EGFR-eGFP dimers into higher-order complexes and cause parallel increases in EGFR phosphorylation. The kinetics of EGFR clustering and phosphorylation were both rapid, plateauing within 2 minutes after stimulation with 30 nM EGF. A rule-based model was formulated to interpret the data. This model took into account ligand binding, ligand-induced conformational changes in the cytosolic tail, monomer-dimer-trimer-tetramer transitions via ectodomain- and kinase-mediated interactions, and phosphorylation. The model predicts that cyclic EGFR tetramers are the predominant phosphorylated species, in which activated receptor dimers adopt a cyclic side-by-side orientation, and that receptor kinase activation is stabilised by the intramolecular interactions responsible for cyclic tetramerization.
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Affiliation(s)
- Noga Kozer
- Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Dipak Barua
- Theoretical Biology and Biophysics Group, Theoretical Division & Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Suzanne Orchard
- Ludwig Institute for Cancer Research, Melbourne-Parkville Branch, PO Box 2008, Royal Melbourne Hospital, Victoria 3050, Australia
| | - Eduoard C. Nice
- Ludwig Institute for Cancer Research, Melbourne-Parkville Branch, PO Box 2008, Royal Melbourne Hospital, Victoria 3050, Australia
- Department of Biochemistry, Monash University, Clayton, Victoria 3080, Australia
| | - Antony W. Burgess
- Ludwig Institute for Cancer Research, Melbourne-Parkville Branch, PO Box 2008, Royal Melbourne Hospital, Victoria 3050, Australia
| | - William S. Hlavacek
- Theoretical Biology and Biophysics Group, Theoretical Division & Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Andrew H.A. Clayton
- Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
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32
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Small molecule inhibition of the KRAS-PDEδ interaction impairs oncogenic KRAS signalling. Nature 2013; 497:638-42. [PMID: 23698361 DOI: 10.1038/nature12205] [Citation(s) in RCA: 470] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 04/19/2013] [Indexed: 12/30/2022]
Abstract
The KRAS oncogene product is considered a major target in anticancer drug discovery. However, direct interference with KRAS signalling has not yet led to clinically useful drugs. Correct localization and signalling by farnesylated KRAS is regulated by the prenyl-binding protein PDEδ, which sustains the spatial organization of KRAS by facilitating its diffusion in the cytoplasm. Here we report that interfering with binding of mammalian PDEδ to KRAS by means of small molecules provides a novel opportunity to suppress oncogenic RAS signalling by altering its localization to endomembranes. Biochemical screening and subsequent structure-based hit optimization yielded inhibitors of the KRAS-PDEδ interaction that selectively bind to the prenyl-binding pocket of PDEδ with nanomolar affinity, inhibit oncogenic RAS signalling and suppress in vitro and in vivo proliferation of human pancreatic ductal adenocarcinoma cells that are dependent on oncogenic KRAS. Our findings may inspire novel drug discovery efforts aimed at the development of drugs targeting oncogenic RAS.
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Alibhai D, Kelly DJ, Warren S, Kumar S, Margineau A, Serwa RA, Thinon E, Alexandrov Y, Murray EJ, Stuhmeier F, Tate EW, Neil MAA, Dunsby C, French PMW. Automated fluorescence lifetime imaging plate reader and its application to Förster resonant energy transfer readout of Gag protein aggregation. JOURNAL OF BIOPHOTONICS 2013; 6:398-408. [PMID: 23184449 PMCID: PMC3660788 DOI: 10.1002/jbio.201200185] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/05/2012] [Accepted: 10/14/2012] [Indexed: 05/29/2023]
Abstract
Fluorescence lifetime measurements can provide quantitative readouts of local fluorophore environment and can be applied to biomolecular interactions via Förster resonant energy transfer (FRET). Fluorescence lifetime imaging (FLIM) can therefore provide a high content analysis (HCA) modality to map protein-protein interactions (PPIs) with applications in drug discovery, systems biology and basic research. We present here an automated multiwell plate reader able to perform rapid unsupervised optically sectioned FLIM of fixed and live biological samples and illustrate its potential to assay PPIs through application to Gag protein aggregation during the HIV life cycle. We demonstrate both hetero-FRET and homo-FRET readouts of protein aggregation and report the first quantitative evaluation of a FLIM HCA assay by generating dose response curves through addition of an inhibitor of Gag myristoylation. Z' factors exceeding 0.6 are realised for this FLIM FRET assay.
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Affiliation(s)
- Dominic Alibhai
- Institute of Chemical Biology, Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2A, UK
| | - Douglas J Kelly
- Institute of Chemical Biology, Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2A, UK
| | - Sean Warren
- Institute of Chemical Biology, Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2A, UK
| | - Sunil Kumar
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Anca Margineau
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Remigiusz A Serwa
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Emmanuelle Thinon
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Yuriy Alexandrov
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | | | - Frank Stuhmeier
- Pfizer Worldwide Research and DevelopmentPfizer Limited, Sandwich, Kent, CT13 9NJ, UK
| | - Edward W Tate
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Mark A A Neil
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Chris Dunsby
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
- Centre for Histopathology, Imperial College LondonDu Cane Rd, London, UK
| | - Paul M W French
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
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Blank LM. The cell and P: from cellular function to biotechnological application. Curr Opin Biotechnol 2012; 23:846-51. [DOI: 10.1016/j.copbio.2012.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/10/2012] [Accepted: 08/15/2012] [Indexed: 01/24/2023]
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Roda-Navarro P. Microspectroscopy reveals mechanisms of lymphocyte activation. Integr Biol (Camb) 2012; 5:300-11. [PMID: 23114860 DOI: 10.1039/c2ib20190a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The immunological synapse (IS) regulates immune responses by integrating extracellular stimuli into intracellular signalling networks, which causes leukocyte differentiation and effector functions. The dynamic spatial organisation of molecules at the IS was initially characterised by wide-field fluorescence microscopy of cell conjugates and cells interacting with planar lipid bilayers. These methods showed stable supramolecular clusters of several microns in size, which were proposed to be responsible for sustained signalling and cell-cell adhesion. The recent emergence of microspectroscopy techniques with higher spatial and temporal resolution nonetheless reveals the complex dynamics of molecular reactions that mediate IS assembly and function. This review describes microspectroscopy-based in vitro experimental approaches for imaging the molecular dynamics at the IS, as well as their contributions and open questions in the field. It also describes experimental methods to obtain quantitative parameters of dynamic biochemical reactions in living cells, and discusses about the important role of quantitative imaging and theoretical science in our understanding of molecular mechanisms underlying lymphocyte activation.
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Affiliation(s)
- Pedro Roda-Navarro
- Department of Microbiology I, Faculty of Medicine, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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36
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Schuermann KC, Grecco HE. flatFLIM: enhancing the dynamic range of frequency domain FLIM. OPTICS EXPRESS 2012; 20:20730-41. [PMID: 23037122 DOI: 10.1364/oe.20.020730] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Fluorescence Lifetime Imaging Microscopy (FLIM) is a quantitative technique to probe the nanoenvironment of fluorescent molecules. It is the most robust way to quantify Förster Resonance Energy Transfer (FRET) as it allows reliable differentiation between concentration changes and quenching. In this way, molecular interactions can be imaged in single living cells. The most common wide-field implementation is homodyne Frequency Domain (FD) FLIM, which determines the fluorescence lifetime by measuring the phase and modulation changes of the fluorescence in each pixel upon excitation with a light source modulated at a high frequency. The fluorescence lifetimes are derived from a stack of images acquired at different phase shifts between excitation and detection. In this work we describe a simple method to enhance the dynamic range of FD-FLIM based on precompensating the expected fluorescence modulation by varying the laser power through the phase stack. We show theoretically and experimentally that most of the dynamic range of the camera can be recovered to quantify cells with different intensities. This improvement can be added to any FD-FLIM setup with minimal modifications, enhancing the throughput of information content.
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Affiliation(s)
- Klaus C Schuermann
- Department of Systemic Cell Biology, Max Planck Institut für molekulare Physiologie, Otto-Hahn-Strasse 11, 44221 Dortmund, Germany
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Optimizing cell arrays for accurate functional genomics. BMC Res Notes 2012; 5:358. [PMID: 22805280 PMCID: PMC3541979 DOI: 10.1186/1756-0500-5-358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 06/14/2012] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Cellular responses emerge from a complex network of dynamic biochemical reactions. In order to investigate them is necessary to develop methods that allow perturbing a high number of gene products in a flexible and fast way. Cell arrays (CA) enable such experiments on microscope slides via reverse transfection of cellular colonies growing on spotted genetic material. In contrast to multi-well plates, CA are susceptible to contamination among neighboring spots hindering accurate quantification in cell-based screening projects. Here we have developed a quality control protocol for quantifying and minimizing contamination in CA. RESULTS We imaged checkered CA that express two distinct fluorescent proteins and segmented images into single cells to quantify the transfection efficiency and interspot contamination. Compared with standard procedures, we measured a 3-fold reduction of contaminants when arrays containing HeLa cells were washed shortly after cell seeding. We proved that nucleic acid uptake during cell seeding rather than migration among neighboring spots was the major source of contamination. Arrays of MCF7 cells developed without the washing step showed 7-fold lower percentage of contaminant cells, demonstrating that contamination is dependent on specific cell properties. CONCLUSIONS Previously published methodological works have focused on achieving high transfection rate in densely packed CA. Here, we focused in an equally important parameter: The interspot contamination. The presented quality control is essential for estimating the rate of contamination, a major source of false positives and negatives in current microscopy based functional genomics screenings. We have demonstrated that a washing step after seeding enhances CA quality for HeLA but is not necessary for MCF7. The described method provides a way to find optimal seeding protocols for cell lines intended to be used for the first time in CA.
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38
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Wood KC, Konieczkowski DJ, Johannessen CM, Boehm JS, Tamayo P, Botvinnik OB, Mesirov JP, Hahn WC, Root DE, Garraway LA, Sabatini DM. MicroSCALE screening reveals genetic modifiers of therapeutic response in melanoma. Sci Signal 2012; 5:rs4. [PMID: 22589389 DOI: 10.1126/scisignal.2002612] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cell microarrays are a promising tool for performing large-scale functional genomic screening in mammalian cells at reasonable cost, but owing to technical limitations they have been restricted for use with a narrow range of cell lines and short-term assays. Here, we describe MicroSCALE (Microarrays of Spatially Confined Adhesive Lentiviral Features), a cell microarray-based platform that enables application of this technology to a wide range of cell types and longer-term assays. We used MicroSCALE to uncover kinases that when overexpressed partially desensitized B-RAFV600E-mutant melanoma cells to inhibitors of the mitogen-activated protein kinase kinase kinase (MAPKKK) RAF, the MAPKKs MEK1 and 2 (MEK1/2, mitogen-activated protein kinase kinase 1 and 2), mTOR (mammalian target of rapamycin), or PI3K (phosphatidylinositol 3-kinase). These screens indicated that cells treated with inhibitors acting through common mechanisms were affected by a similar profile of overexpressed proteins. In contrast, screens involving inhibitors acting through distinct mechanisms yielded unique profiles, a finding that has potential relevance for small-molecule target identification and combination drugging studies. Further, by integrating large-scale functional screening results with cancer cell line gene expression and pharmacological sensitivity data, we validated the nuclear factor κB pathway as a potential mediator of resistance to MAPK pathway inhibitors. The MicroSCALE platform described here may enable new classes of large-scale, resource-efficient screens that were not previously feasible, including those involving combinations of cell lines, perturbations, and assay outputs or those involving limited numbers of cells and limited or expensive reagents.
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Affiliation(s)
- Kris C Wood
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA.
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39
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Padilla-Parra S, Tramier M. FRET microscopy in the living cell: Different approaches, strengths and weaknesses. Bioessays 2012; 34:369-76. [DOI: 10.1002/bies.201100086] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/15/2011] [Accepted: 09/28/2011] [Indexed: 02/02/2023]
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40
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Ehn A, Johansson O, Arvidsson A, Aldén M, Bood J. Single-laser shot fluorescence lifetime imaging on the nanosecond timescale using a Dual Image and Modeling Evaluation algorithm. OPTICS EXPRESS 2012; 20:3043-3056. [PMID: 22330541 DOI: 10.1364/oe.20.003043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A novel technique, designated dual imaging and modeling evaluation (DIME), for evaluating single-laser shot fluorescence lifetimes is presented. The technique is experimentally verified in a generic gas mixing experiment to provide a clear demonstration of the rapidness and sensitivity of the detector scheme. Single-laser shot fluorescence lifetimes of roughly 800 ps with a standard deviation of ~120 ps were determined. These results were compared to streak camera measurements. Furthermore, a general fluorescence lifetime determination algorithm is proposed. The evaluation algorithm has an analytic, linear relationship between the fluorescence lifetime and detector signal ratio. In combination with the DIME detector scheme, it is a faster, more accurate and more sensitive approach for rapid fluorescence lifetime imaging than previously proposed techniques. Monte Carlo simulations were conducted to analyze the sensitivity of the detector scheme as well as to compare the proposed evaluation algorithm to previously presented rapid lifetime determination algorithms.
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Affiliation(s)
- Andreas Ehn
- Division of Combustion Physics, Lund University, Box 118, SE-221 00 Lund, Sweden.
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41
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Antczak C, Bermingham A, Calder P, Malkov D, Song K, Fetter J, Djaballah H. Domain-based biosensor assay to screen for epidermal growth factor receptor modulators in live cells. Assay Drug Dev Technol 2012; 10:24-36. [PMID: 22280060 DOI: 10.1089/adt.2011.423] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Traditional drug discovery efforts have resulted in the approval of a handful of receptor tyrosine kinase (RTK) inhibitors; however, their discovery relied solely on screening recombinant kinases, often with poor cellular activity outcome. The ability to screen RTKs in their natural environment is sought as an alternative approach. We have adapted a novel strategy utilizing a green fluorescent protein-labeled SRC homology 2 domain-based biosensor as a surrogate reporter of endogenous epidermal growth factor receptor (EGFR) activity in A549 cells. Upon activation of the receptor, EGFR function in live cells is measured by the number of green granules that form. Here we describe assay miniaturization and demonstrate specificity for EGFR through its chemical inhibition and RNAi-dependent knockdown resulting in complete abrogation of granule formation. Gefitinib and PD 153035 were identified as hits in a pilot screen. This approach allows for the identification of novel EGFR modulators in high-throughput formats for screening chemical and RNAi libraries.
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Affiliation(s)
- Christophe Antczak
- HTS Core Facility, Molecular Pharmacology & Chemistry Program, Memorial Sloan-Kettering Cancer Center , New York, New York 10065, USA
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42
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Grecco HE, Roda-Navarro P, Fengler S, Bastiaens PIH. High-throughput quantification of posttranslational modifications in situ by CA-FLIM. Methods Enzymol 2012; 500:37-58. [PMID: 21943891 DOI: 10.1016/b978-0-12-385118-5.00003-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Signal transduction is mediated by posttranslational modifications (PTMs) of proteins in complex signaling networks. Quantifying PTM levels of multiple network components in response to a stimulus is therefore the key to understand how their concerted activities give rise to cellular function. We have shown that fluorescence lifetime imaging microscopy (FLIM) on cell arrays (CA-FLIM) provides a method to accurately quantify PTM levels of many proteins in situ. Herein, we describe the detailed protocol for CA-FLIM. Less than 2 days are needed from cell array preparation to data analysis, where the main limiting step is the 24h needed for transfection. After generating a single cell array containing 384 spots, it can be imaged and analyzed in less than 2h.
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Affiliation(s)
- Hernán E Grecco
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
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Pereira AM, Tudor C, Kanger JS, Subramaniam V, Martin-Blanco E. Integrin-dependent activation of the JNK signaling pathway by mechanical stress. PLoS One 2011; 6:e26182. [PMID: 22180774 PMCID: PMC3236745 DOI: 10.1371/journal.pone.0026182] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 09/21/2011] [Indexed: 02/07/2023] Open
Abstract
Mechanical force is known to modulate the activity of the Jun N-terminal kinase (JNK) signaling cascade. However, the effect of mechanical stresses on JNK signaling activation has previously only been analyzed by in vitro detection methods. It still remains unknown how living cells activate the JNK signaling cascade in response to mechanical stress and what its functions are in stretched cells. We assessed in real-time the activity of the JNK pathway in Drosophila cells by Fluorescence Lifetime Imaging Microscopy (FLIM), using an intramolecular phosphorylation-dependent dJun-FRET (Fluorescence Resonance Energy Transfer) biosensor. We found that quantitative FRET-FLIM analysis and confocal microscopy revealed sustained dJun-FRET biosensor activation and stable morphology changes in response to mechanical stretch for Drosophila S2R+ cells. Further, these cells plated on different substrates showed distinct levels of JNK activity that associate with differences in cell morphology, integrin expression and focal adhesion organization. These data imply that alterations in the cytoskeleton and matrix attachments may act as regulators of JNK signaling, and that JNK activity might feed back to modulate the cytoskeleton and cell adhesion. We found that this dynamic system is highly plastic; at rest, integrins at focal adhesions and talin are key factors suppressing JNK activity, while multidirectional static stretch leads to integrin-dependent, and probably talin-independent, Jun sensor activation. Further, our data suggest that JNK activity has to coordinate with other signaling elements for the regulation of the cytoskeleton and cell shape remodeling associated with stretch.
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Affiliation(s)
- Andrea Maria Pereira
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Barcelona, Spain
| | - Cicerone Tudor
- Nanobiophysics, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Johannes S. Kanger
- Nanobiophysics, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Vinod Subramaniam
- Nanobiophysics, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
- * E-mail: (EMB); (VS)
| | - Enrique Martin-Blanco
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Barcelona, Spain
- * E-mail: (EMB); (VS)
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Miyawaki A. Development of Probes for Cellular Functions Using Fluorescent Proteins and Fluorescence Resonance Energy Transfer. Annu Rev Biochem 2011; 80:357-73. [DOI: 10.1146/annurev-biochem-072909-094736] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Atsushi Miyawaki
- Laboratory for Cell Function and Dynamics, Brain Science Institute, RIKEN, Wako-city, Saitama 351-0198, Japan;
- Life Function and Dynamics, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Wako-city, Saitama 351-0198, Japan
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45
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McGhee EJ, Morton JP, Von Kriegsheim A, Schwarz JP, Karim SA, Carragher NO, Sansom OJ, Anderson KI, Timpson P. FLIM-FRET imaging in vivo reveals 3D-environment spatially regulates RhoGTPase activity during cancer cell invasion. Small GTPases 2011; 2:239-244. [PMID: 22145098 PMCID: PMC3225915 DOI: 10.4161/sgtp.2.4.17275] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 07/13/2011] [Indexed: 11/19/2022] Open
Abstract
Many conceptual advances in biology have been achieved by experimental studies using planar two-dimensional cell culture systems. Recent adaptations of molecular techniques to three-dimensional model systems are bridging the gap in our understanding of biological events in vitro and in vivo in the study of disease progression. Recently, in vitro studies using Förster resonance energy transfer (FRET) have shown that the prototypical RhoGTPases Cdc42, Rac and RhoA are temporally and spatially synchronized during cell migration, with initial RhoA activity inducing protrusion prior to activation of Rac. This simultaneous FRET approach illustrates the tight control and dynamic regulation of RhoGTPase activity necessary for coordinated cell migration in vitro. Here, we discuss our recent work using FLIM-FRET analysis in a three-dimensional setting to reveal another layer of regulation in which RhoA activity is governed by the extracellular microenvironment. We demonstrate that RhoA is spatially regulated into discrete fractions of activity at the leading edge and rear of cells during invasion in vivo or within three-dimensional matrices. Significantly, this spatial regulation of RhoA was absent in two-dimensional in vitro settings. This distinct sub-cellular regulation of RhoA at the poles of invading cells in three-dimensions sets a precedent that other RhoGTPases or signaling proteins may also be differentially regulated in a con-text-dependent manner during key biological processes such as invasion.
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Affiliation(s)
- Ewan J McGhee
- The Beatson Institute for Cancer Research; Glasgow; Edinburgh, UK
| | | | | | | | - Saadia A Karim
- The Beatson Institute for Cancer Research; Glasgow; Edinburgh, UK
| | - Neil O Carragher
- Edinburgh Cancer Research Centre; Institute of Genetics and Molecular Medicine; University of Edinburgh; Edinburgh, UK
| | - Owen J Sansom
- The Beatson Institute for Cancer Research; Glasgow; Edinburgh, UK
| | - Kurt I Anderson
- The Beatson Institute for Cancer Research; Glasgow; Edinburgh, UK
| | - Paul Timpson
- The Beatson Institute for Cancer Research; Glasgow; Edinburgh, UK
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46
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Affiliation(s)
- Yuqing Lin
- Department of Chemistry, University of Gothenburg, S-41296, Gothenburg, Sweden
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47
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Wu JH, Guan Z, Xu TZ, Xu QH, Xu GQ. Tetracene-doped anthracene nanowire arrays: preparation and doping effects. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6374-6380. [PMID: 21480618 DOI: 10.1021/la200569v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Large-scale tetracene-doped anthracene nanowire arrays were prepared, and the doping effects were studied. The high doping concentration up to 10% (molar ratio) has been achieved, attributed to both the unique long-nanowire geometry and the excellent structural compatibility of anthracene and tetracene. The incorporation of long tetracene molecules into the matrix of short anthracene molecules induced an enlarged interlayer thickness, a decreased nanowire thickness, and an expanded nanowire width. The tetracene molecules were homogeneously embedded into the anthracene matrix at low doping concentrations (<1%). The doping became inhomogeneous at high doping concentrations (≥1%). The energy transfer efficiency between anthracene and tetracene is nearly 100% at doping concentrations ≥1%.
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Affiliation(s)
- Ji Hong Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Republic of Singapore 117543
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48
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Non fitting based FRET-FLIM analysis approaches applied to quantify protein-protein interactions in live cells. Biophys Rev 2011; 3:63-70. [PMID: 28510004 DOI: 10.1007/s12551-011-0047-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 04/26/2011] [Indexed: 01/14/2023] Open
Abstract
New imaging methodologies in quantitative fluorescence microscopy and nanoscopy have been developed in the last few years and are beginning to be extensively applied to biological problems, such as the localization and quantification of protein interactions. Fluorescence resonance energy transfer (FRET) detected by fluorescence lifetime imaging microscopy (FLIM) is currently employed not only in biophysics or chemistry but also in bio-medicine, thanks to new advancements in technology and also new developments in data treatment. FRET-FLIM can be a very useful tool to ascertain protein interactions occurring in single living cells. In this review, we stress the importance of increasing the acquisition speed when working in vivo employing Time-Domain FLIM. The development of the new mathematical-based non-fitting methods allows the determining of the fraction of interacting donor without the requirement of high count statistics, and thus allows the performing of high speed acquisitions in FRET-FLIM to still be quantitative.
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49
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Live cell in vitro and in vivo imaging applications: accelerating drug discovery. Pharmaceutics 2011; 3:141-70. [PMID: 24310493 PMCID: PMC3864231 DOI: 10.3390/pharmaceutics3020141] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 03/21/2011] [Accepted: 03/31/2011] [Indexed: 12/20/2022] Open
Abstract
Dynamic regulation of specific molecular processes and cellular phenotypes in live cell systems reveal unique insights into cell fate and drug pharmacology that are not gained from traditional fixed endpoint assays. Recent advances in microscopic imaging platform technology combined with the development of novel optical biosensors and sophisticated image analysis solutions have increased the scope of live cell imaging applications in drug discovery. We highlight recent literature examples where live cell imaging has uncovered novel insight into biological mechanism or drug mode-of-action. We survey distinct types of optical biosensors and associated analytical methods for monitoring molecular dynamics, in vitro and in vivo. We describe the recent expansion of live cell imaging into automated target validation and drug screening activities through the development of dedicated brightfield and fluorescence kinetic imaging platforms. We provide specific examples of how temporal profiling of phenotypic response signatures using such kinetic imaging platforms can increase the value of in vitro high-content screening. Finally, we offer a prospective view of how further application and development of live cell imaging technology and reagents can accelerate preclinical lead optimization cycles and enhance the in vitro to in vivo translation of drug candidates.
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50
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Kumar S, Alibhai D, Margineanu A, Laine R, Kennedy G, McGinty J, Warren S, Kelly D, Alexandrov Y, Munro I, Talbot C, Stuckey DW, Kimberly C, Viellerobe B, Lacombe F, Lam EWF, Taylor H, Dallman MJ, Stamp G, Murray EJ, Stuhmeier F, Sardini A, Katan M, Elson DS, Neil MAA, Dunsby C, French PMW. FLIM FRET technology for drug discovery: automated multiwell-plate high-content analysis, multiplexed readouts and application in situ. Chemphyschem 2011; 12:609-26. [PMID: 21337485 PMCID: PMC3084521 DOI: 10.1002/cphc.201000874] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/07/2010] [Indexed: 11/10/2022]
Abstract
A fluorescence lifetime imaging (FLIM) technology platform intended to read out changes in Förster resonance energy transfer (FRET) efficiency is presented for the study of protein interactions across the drug-discovery pipeline. FLIM provides a robust, inherently ratiometric imaging modality for drug discovery that could allow the same sensor constructs to be translated from automated cell-based assays through small transparent organisms such as zebrafish to mammals. To this end, an automated FLIM multiwell-plate reader is described for high content analysis of fixed and live cells, tomographic FLIM in zebrafish and FLIM FRET of live cells via confocal endomicroscopy. For cell-based assays, an exemplar application reading out protein aggregation using FLIM FRET is presented, and the potential for multiple simultaneous FLIM (FRET) readouts in microscopy is illustrated.
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Affiliation(s)
- Sunil Kumar
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK.
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