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Dhamija S, De AK. Elucidating Contributions from Multiple Species during Photoconversion of Enhanced Green Fluorescent Protein (EGFP) under Ultraviolet Illumination. Photochem Photobiol 2021; 97:980-990. [PMID: 33624317 DOI: 10.1111/php.13409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 02/21/2021] [Indexed: 11/30/2022]
Abstract
Photocycle in wild-type green fluorescent protein (wt-GFP) involves generation of a bright fluorescent deprotonated chromophore from feebly fluorescent protonated form via excited-state proton transfer. In addition to this usual photocycle, wt-GFP is also known to exhibit irreversible photoconversion upon illumination with ultraviolet and visible radiation. However, a detailed understanding of photoconversion in enhanced GFP (EGFP: S65T/F64L mutant of wt-GFP), which predominantly exists in deprotonated form, is yet to be explored. Using 254 nm irradiation, we study how photoconversion proceeds in EGFP. The key findings are observation of spreading out of an isosbestic point and existence of an initial lag phase in spectral kinetics of absorbance, indicative of sequential photoconversion through an intermediate. Fluorescence kinetics of EGFP and its photoproduct are estimated by assigning two unique fluorescence lifetimes which is further complicated by the fact that their fluorescence are spectrally inseparable, as evident from global analysis of fluorescence lifetime. Time-resolved fluorescence anisotropy studies further suggest minimal structural changes in protein scaffold upon photoconversion. Based on these findings, an analytic model is developed to account for the overall decay in fluorescence (as photoconversion proceeds) that inherently incorporates the initial lag phase and a summary of energetics and processes involved is provided.
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Affiliation(s)
- Shaina Dhamija
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Punjab, India
| | - Arijit K De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, Punjab, India
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2
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Herman P, Holoubek A, Brodska B. Lifetime-based photoconversion of EGFP as a tool for FLIM. Biochim Biophys Acta Gen Subj 2019; 1863:266-277. [DOI: 10.1016/j.bbagen.2018.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 01/10/2023]
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3
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Radbruch H, Bremer D, Mothes R, Günther R, Rinnenthal JL, Pohlan J, Ulbricht C, Hauser AE, Niesner R. Intravital FRET: Probing Cellular and Tissue Function in Vivo. Int J Mol Sci 2015; 16:11713-27. [PMID: 26006244 PMCID: PMC4463726 DOI: 10.3390/ijms160511713] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/13/2015] [Indexed: 12/02/2022] Open
Abstract
The development of intravital Förster Resonance Energy Transfer (FRET) is required to probe cellular and tissue function in the natural context: the living organism. Only in this way can biomedicine truly comprehend pathogenesis and develop effective therapeutic strategies. Here we demonstrate and discuss the advantages and pitfalls of two strategies to quantify FRET in vivo-ratiometrically and time-resolved by fluorescence lifetime imaging-and show their concrete application in the context of neuroinflammation in adult mice.
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Affiliation(s)
- Helena Radbruch
- Neuropathology, Charité-University of Medicine, Berlin 10117, Germany.
| | - Daniel Bremer
- Germany German Rheumatism Research Center, Berlin 10117, Germany.
| | - Ronja Mothes
- Neuropathology, Charité-University of Medicine, Berlin 10117, Germany.
- Germany German Rheumatism Research Center, Berlin 10117, Germany.
| | - Robert Günther
- Germany German Rheumatism Research Center, Berlin 10117, Germany.
| | | | - Julian Pohlan
- Neuropathology, Charité-University of Medicine, Berlin 10117, Germany.
- Germany German Rheumatism Research Center, Berlin 10117, Germany.
| | - Carolin Ulbricht
- Germany German Rheumatism Research Center, Berlin 10117, Germany.
- Immundynamics and Intravital Microscopy, Charité-University of Medicine, Berlin 10117, Germany.
| | - Anja E Hauser
- Germany German Rheumatism Research Center, Berlin 10117, Germany.
- Immundynamics and Intravital Microscopy, Charité-University of Medicine, Berlin 10117, Germany.
| | - Raluca Niesner
- Germany German Rheumatism Research Center, Berlin 10117, Germany.
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4
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Hoffmann B, Klöcker N, Benndorf K, Biskup C. Visualization of the dynamics of PSD-95 and Kir2.1 interaction by fluorescence lifetime-based resonance energy transfer imaging. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.medpho.2014.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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5
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Becker W. Fluorescence lifetime imaging by multi-dimensional time correlated single photon counting. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.medpho.2015.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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6
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Habenicht SH, Schramm S, Zhu M, Freund RRA, Langenstück T, Strathausen R, Weiß D, Biskup C, Beckert R. π-Extension of a 4-ethoxy-1,3-thiazole via aryl alkyne cross coupling: synthesis and exploration of the electronic structure. Photochem Photobiol Sci 2015; 14:2097-107. [DOI: 10.1039/c5pp00219b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
π-Extension of 4-ethoxy-1,3-thiazolesviaaryl coupling resulted in a twofold increase of molar extinction coefficients and larger Stokes’ shifts.
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Affiliation(s)
- Stefanie H. Habenicht
- Institute of Organic Chemistry and Macromolecular Chemistry
- Friedrich Schiller University
- 07743 Jena
- Germany
| | - Stefan Schramm
- Institute of Organic Chemistry and Macromolecular Chemistry
- Friedrich Schiller University
- 07743 Jena
- Germany
| | - Mingming Zhu
- Institute of Organic Chemistry and Macromolecular Chemistry
- Friedrich Schiller University
- 07743 Jena
- Germany
| | - Robert R. A. Freund
- Institute of Organic Chemistry and Macromolecular Chemistry
- Friedrich Schiller University
- 07743 Jena
- Germany
| | - Teresa Langenstück
- Biomolecular Photonics Group
- Jena University Hospital
- Friedrich Schiller University
- 07743 Jena
- Germany
| | - Rainer Strathausen
- Institute of Organic Chemistry and Macromolecular Chemistry
- Friedrich Schiller University
- 07743 Jena
- Germany
- Biomolecular Photonics Group
| | - Dieter Weiß
- Institute of Organic Chemistry and Macromolecular Chemistry
- Friedrich Schiller University
- 07743 Jena
- Germany
| | - Christoph Biskup
- Biomolecular Photonics Group
- Jena University Hospital
- Friedrich Schiller University
- 07743 Jena
- Germany
| | - Rainer Beckert
- Institute of Organic Chemistry and Macromolecular Chemistry
- Friedrich Schiller University
- 07743 Jena
- Germany
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7
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Richert L, Didier P, de Rocquigny H, Mély Y. Monitoring HIV-1 Protein Oligomerization by FLIM FRET Microscopy. SPRINGER SERIES IN CHEMICAL PHYSICS 2015. [DOI: 10.1007/978-3-319-14929-5_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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8
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Drepper T, Gensch T, Pohl M. Advanced in vivo applications of blue light photoreceptors as alternative fluorescent proteins. Photochem Photobiol Sci 2014; 12:1125-34. [PMID: 23660639 DOI: 10.1039/c3pp50040c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ultimate ambition in cell biology, microbiology and biomedicine is to unravel complex physiological and pathophysiological processes within living organisms. To conquer this challenge, fluorescent proteins (FPs) are used as versatile in vivo reporters and biosensors to study gene regulation as well as the synthesis, localization and function of proteins in living cells. The most widely used FPs are the green fluorescent protein (GFP) and its derivatives and relatives. Their use as in vivo reporter proteins, however, is sometimes restricted by different environmental and cellular factors. Consequently, a whole range of alternative, cofactor-dependent reporter proteins have been developed recently. In this perspective, we summarize the advantages and limitations of the novel class of cyan-green fluorescent flavoproteins in comparison to members of the GFP family and discuss some correlated consequences for the use of FPs as in vivo reporters.
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Affiliation(s)
- Thomas Drepper
- Institute of Molecular Enzyme Technology, Heinrich-Heine-University Duesseldorf, Forschungszentrum Jülich, 52425 Juelich, Germany.
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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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10
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Rinnenthal JL, Börnchen C, Radbruch H, Andresen V, Mossakowski A, Siffrin V, Seelemann T, Spiecker H, Moll I, Herz J, Hauser AE, Zipp F, Behne MJ, Niesner R. Parallelized TCSPC for dynamic intravital fluorescence lifetime imaging: quantifying neuronal dysfunction in neuroinflammation. PLoS One 2013; 8:e60100. [PMID: 23613717 PMCID: PMC3629055 DOI: 10.1371/journal.pone.0060100] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 02/22/2013] [Indexed: 01/27/2023] Open
Abstract
Two-photon laser-scanning microscopy has revolutionized our view on vital processes by revealing motility and interaction patterns of various cell subsets in hardly accessible organs (e.g. brain) in living animals. However, current technology is still insufficient to elucidate the mechanisms of organ dysfunction as a prerequisite for developing new therapeutic strategies, since it renders only sparse information about the molecular basis of cellular response within tissues in health and disease. In the context of imaging, Förster resonant energy transfer (FRET) is one of the most adequate tools to probe molecular mechanisms of cell function. As a calibration-free technique, fluorescence lifetime imaging (FLIM) is superior for quantifying FRET in vivo. Currently, its main limitation is the acquisition speed in the context of deep-tissue 3D and 4D imaging. Here we present a parallelized time-correlated single-photon counting point detector (p-TCSPC) (i) for dynamic single-beam scanning FLIM of large 3D areas on the range of hundreds of milliseconds relevant in the context of immune-induced pathologies as well as (ii) for ultrafast 2D FLIM in the range of tens of milliseconds, a scale relevant for cell physiology. We demonstrate its power in dynamic deep-tissue intravital imaging, as compared to multi-beam scanning time-gated FLIM suitable for fast data acquisition and compared to highly sensitive single-channel TCSPC adequate to detect low fluorescence signals. Using p-TCSPC, 256×256 pixel FLIM maps (300×300 µm(2)) are acquired within 468 ms while 131×131 pixel FLIM maps (75×75 µm(2)) can be acquired every 82 ms in 115 µm depth in the spinal cord of CerTN L15 mice. The CerTN L15 mice express a FRET-based Ca-biosensor in certain neuronal subsets. Our new technology allows us to perform time-lapse 3D intravital FLIM (4D FLIM) in the brain stem of CerTN L15 mice affected by experimental autoimmune encephalomyelitis and, thereby, to truly quantify neuronal dysfunction in neuroinflammation.
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Affiliation(s)
- Jan Leo Rinnenthal
- German Rheumatism Research Center, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Christian Börnchen
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Helena Radbruch
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | | | - Agata Mossakowski
- German Rheumatism Research Center, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Volker Siffrin
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Neurology Department, Johannes Gutenberg University Mainz, Mainz, Germany
| | | | | | - Ingrid Moll
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Josephine Herz
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Anja E. Hauser
- German Rheumatism Research Center, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
| | - Frauke Zipp
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Neurology Department, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Martin J. Behne
- Department of Dermatology and Venerology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Raluca Niesner
- German Rheumatism Research Center, Berlin, Germany
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
- Charité – University of Medicine, Berlin, Germany
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11
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Stender AS, Marchuk K, Liu C, Sander S, Meyer MW, Smith EA, Neupane B, Wang G, Li J, Cheng JX, Huang B, Fang N. Single cell optical imaging and spectroscopy. Chem Rev 2013; 113:2469-527. [PMID: 23410134 PMCID: PMC3624028 DOI: 10.1021/cr300336e] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Anthony S. Stender
- Department of Chemistry, Iowa State University and Ames Laboratory, U. S. Department of Energy, Ames, IA 50011, USA
| | - Kyle Marchuk
- Department of Chemistry, Iowa State University and Ames Laboratory, U. S. Department of Energy, Ames, IA 50011, USA
| | - Chang Liu
- Department of Chemistry, Iowa State University and Ames Laboratory, U. S. Department of Energy, Ames, IA 50011, USA
| | - Suzanne Sander
- Department of Chemistry, Iowa State University and Ames Laboratory, U. S. Department of Energy, Ames, IA 50011, USA
| | - Matthew W. Meyer
- Department of Chemistry, Iowa State University and Ames Laboratory, U. S. Department of Energy, Ames, IA 50011, USA
| | - Emily A. Smith
- Department of Chemistry, Iowa State University and Ames Laboratory, U. S. Department of Energy, Ames, IA 50011, USA
| | - Bhanu Neupane
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Gufeng Wang
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Junjie Li
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
| | - Bo Huang
- Department of Pharmaceutical Chemistry and Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Ning Fang
- Department of Chemistry, Iowa State University and Ames Laboratory, U. S. Department of Energy, Ames, IA 50011, USA
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13
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Strachotová D, Holoubek A, Kučerová H, Benda A, Humpolíčková J, Váchová L, Palková Z. Ato protein interactions in yeast plasma membrane revealed by fluorescence lifetime imaging (FLIM). BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2126-34. [PMID: 22579979 DOI: 10.1016/j.bbamem.2012.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 04/29/2012] [Accepted: 05/04/2012] [Indexed: 12/27/2022]
Abstract
Each of the three plasma membrane Ato proteins is involved in ammonium signalling and the development of yeast colonies. This suggests that although these proteins are homologous, they do not functionally substitute for each other, but may form a functional complex. Here, we present a detailed combined FRET, FLIM and photobleaching study, which enabled us to detect interactions between Ato proteins found in distinct compartments of yeast cells. We thus show that the proteins Ato1p and Ato2p interact and can form complexes when present in the plasma membrane. No interaction was detected between Ato1p and Ato3p or Ato2p and Ato3p. In addition, using specially prepared strains, we were able to detect an interaction between molecules of the same Ato protein, namely Ato1p-Ato1p and Ato3p-Ato3p, but not Ato2p-Ato2p.
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14
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Becker W, Su B, Holub O, Weisshart K. FLIM and FCS detection in laser-scanning microscopes: increased efficiency by GaAsP hybrid detectors. Microsc Res Tech 2010; 74:804-11. [PMID: 23939667 DOI: 10.1002/jemt.20959] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 09/29/2010] [Indexed: 11/06/2022]
Abstract
Photon counting detectors currently used in fluorescence lifetime microscopy have a number of deficiencies that result in less-than-ideal signal-to-noise ratio of the lifetimes obtained: either the quantum efficiency is unsatisfactory or the active area is too small, and afterpulsing or tails in the temporal response contribute to overall timing inaccuracy. We have therefore developed a new FLIM detector based on a GaAsP hybrid photomultiplier. Compared with conventional PMTs and SPADs, GaAsP hybrid detectors have a number of advantages: The detection quantum efficiency reaches or surpasses the efficiency of fast SPADs, and the active area is on the order of 5 mm², compared with 2.5 10⁻³ mm² for a SPAD. The TCSPC response is clean, without the bumps and the diffusion tails typical for PMTs and SPADs. Most important, the hybrid detector is intrinsically free of afterpulsing. FLIM results are therefore free of signal-dependent background, and FCS curves are free of the known afterpulsing peak. We demonstrate the performance of the new detector for multiphoton NDD FLIM and for FCS.
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Affiliation(s)
- W Becker
- Becker & Hickl GmbH, Nahmitzer Damm 30, Berlin, Germany.
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15
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Kwaaitaal M, Keinath NF, Pajonk S, Biskup C, Panstruga R. Combined bimolecular fluorescence complementation and Forster resonance energy transfer reveals ternary SNARE complex formation in living plant cells. PLANT PHYSIOLOGY 2010; 152:1135-47. [PMID: 20071602 PMCID: PMC2832253 DOI: 10.1104/pp.109.151142] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 01/08/2010] [Indexed: 05/18/2023]
Abstract
Various fluorophore-based microscopic methods, comprising Förster resonance energy transfer (FRET) and bimolecular fluorescence complementation (BiFC), are suitable to study pairwise interactions of proteins in living cells. The analysis of interactions between more than two protein partners using these methods, however, remains difficult. In this study, we report the successful application of combined BiFC-FRET-fluorescence lifetime imaging microscopy and BiFC-FRET-acceptor photobleaching measurements to visualize the formation of ternary soluble N-ethylmaleimide-sensitive factor attachment receptor complexes in leaf epidermal cells. This method expands the repertoire of techniques to study protein-protein interactions in living plant cells by a procedure capable of visualizing simultaneously interactions between three fluorophore-tagged polypeptide partners.
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Wang L, Chen T, Qu J, Wei X. Quantitative analysis of caspase-3 activation by fitting fluorescence emission spectra in living cells. Micron 2009; 40:811-20. [DOI: 10.1016/j.micron.2009.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/24/2009] [Accepted: 07/02/2009] [Indexed: 10/20/2022]
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17
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Chang CW, Wu M, Merajver SD, Mycek MA. Physiological fluorescence lifetime imaging microscopy improves Förster resonance energy transfer detection in living cells. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:060502. [PMID: 20059233 PMCID: PMC2787065 DOI: 10.1117/1.3257254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Accurate, unambiguous detection of molecular interactions in living cells via measurements of Forster (or fluorescence) resonance energy transfer (FRET) events is experimentally challenging. We develop and apply a physiological fluorescence lifetime imaging microscopy (physiological FLIM) system to significantly improve FRET detection in living cells. Multiple positive and negative cellular controls are implemented to validate the experimental method developed. FLIM measurement techniques were found to remove fluorescence intensity-based artifacts, resulting in a seven-fold improvement in fluorescence measurement precision. The addition of cellular environmental controls, including both temperature and CO(2) stabilization, for physiological FLIM eliminates nonspecific FRET in the live-cell system studied. Overall, only physiological FLIM results in statistically significant results that clearly indicated the presence of specific molecular interactions in the live-cell system. This approach can be applied generally to improve the accuracy and precision of FRET measurements in living cells.
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Wang L, Chen T, Qu J, Wei X. Photobleaching-based quantitative analysis of fluorescence resonance energy transfer inside single living cell. J Fluoresc 2009; 20:27-35. [PMID: 19588234 DOI: 10.1007/s10895-009-0518-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 07/02/2009] [Indexed: 10/20/2022]
Abstract
The current advances of fluorescence microscopy and new fluorescent probes make fluorescence resonance energy transfer (FRET) a powerful technique for studying protein-protein interactions inside living cells. It is very hard to quantitatively analyze FRET efficiency using intensity-based FRET imaging microscopy due to the presence of autofluorescence and spectral crosstalks. In this study, we for the first time developed a novel photobleaching-based method to quantitatively detect FRET efficiency (Pb-FRET) by selectively photobleaching acceptor. The Pb-FRET method requires two fluorescence detection channels: a donor channel (CH ( 1 )) to selectively detect the fluorescence from donor, and a FRET channel (CH ( 2 )) which normally includes the fluorescence from both acceptor and donor due to emission spectral crosstalk. We used the Pb-FRET method to quantitatively measure the FRET efficiency of SCAT3, a caspase-3 indicator based on FRET, inside single living cells stably expressing SCAT3 during STS-induced apoptosis. At 0, 6 and 12 h after STS treatment, the FRET efficiency of SCAT3 obtained by Pb-FRET inside living cells was verified by two-photon excitation (TPE) fluorescence lifetime imaging microscopy (FLIM). The temporal resolution of Pb-FRET method is in second time-scale for ROI photobleaching, even in microsecond time-scale for spot photobleaching. Our results demonstrate that the Pb-FRET method is independent of photobleaching degree, and is very useful for quantitatively monitoring protein-protein interactions inside single living cell.
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Affiliation(s)
- Longxiang Wang
- MOE Key laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou, 510631, China
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19
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Gorlovoy P, Larionov S, Pham TTH, Neumann H. Accumulation of tau induced in neurites by microglial proinflammatory mediators. FASEB J 2009; 23:2502-13. [DOI: 10.1096/fj.08-123877] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Philipp Gorlovoy
- Neural Regeneration UnitInstitute of Reconstructive NeurobiologyUniversity Bonn and Hertie‐FoundationBonnGermany
| | - Sergey Larionov
- Neural Regeneration UnitInstitute of Reconstructive NeurobiologyUniversity Bonn and Hertie‐FoundationBonnGermany
| | - Thao Thi Hien Pham
- Neural Regeneration UnitInstitute of Reconstructive NeurobiologyUniversity Bonn and Hertie‐FoundationBonnGermany
| | - Harald Neumann
- Neural Regeneration UnitInstitute of Reconstructive NeurobiologyUniversity Bonn and Hertie‐FoundationBonnGermany
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Levitt JA, Matthews DR, Ameer-Beg SM, Suhling K. Fluorescence lifetime and polarization-resolved imaging in cell biology. Curr Opin Biotechnol 2009; 20:28-36. [DOI: 10.1016/j.copbio.2009.01.004] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 01/23/2009] [Indexed: 10/21/2022]
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