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Jiang X, Hu M, Cao G, Liu Z, Wu G, Zhuang Z, Chen T. Im-SCC-FRET: improved single-cell-based calibration of a FRET system. OPTICS EXPRESS 2023; 31:43764-43770. [PMID: 38178465 DOI: 10.1364/oe.503323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/29/2023] [Indexed: 01/06/2024]
Abstract
We recently developed a SCC-FRET (single-cell-based calibration of a FRET system) method to quantify spectral crosstalk correction parameters (β and δ) and system calibration parameters (G and k) of a Förster resonance energy transfer (FRET) system by imaging a single cell expressing a standard FRET plasmid with known FRET efficiency (E) and donor-acceptor concentration ratio (RC) (Liu et al., Opt. Express30, 29063 (2022)10.1364/OE.459861). Here we improved the SCC-FRET method (named as Im-SCC-FRET) to simultaneously obtain β, δ, G, k and the acceptor-to-donor extinction coefficient ratio (ε A ε D), which is a key parameter to calculate the acceptor-centric FRET efficiency (EA), of a FRET system when the range of β and δ values is set as 0-1. In Im-SCC-FRET, the target function is changed from the sum of absolute values to the sum of squares according to the least squares method, and the initial value of β and δ estimated by the integral but not the maximum value spectral overlap between fluorophore and filter. Compared with SCC-FRET, the experimental results demonstrate that Im-SCC-FRET can obtain more accurate and stable results for β, δ, G, and k, and add the ratio ε A ε D, which is necessary for the FRET hybrid assay. Im-SCC-FRET reduces the complexity of experiment preparation and opens up a promising avenue for developing an intelligent FRET correction system.
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2
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Chen G, Obal D. Detecting and measuring of GPCR signaling - comparison of human induced pluripotent stem cells and immortal cell lines. Front Endocrinol (Lausanne) 2023; 14:1179600. [PMID: 37293485 PMCID: PMC10244570 DOI: 10.3389/fendo.2023.1179600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 04/12/2023] [Indexed: 06/10/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are a large family of transmembrane proteins that play a major role in many physiological processes, and thus GPCR-targeted drug development has been widely promoted. Although research findings generated in immortal cell lines have contributed to the advancement of the GPCR field, the homogenous genetic backgrounds, and the overexpression of GPCRs in these cell lines make it difficult to correlate the results with clinical patients. Human induced pluripotent stem cells (hiPSCs) have the potential to overcome these limitations, because they contain patient specific genetic information and can differentiate into numerous cell types. To detect GPCRs in hiPSCs, highly selective labeling and sensitive imaging techniques are required. This review summarizes existing resonance energy transfer and protein complementation assay technologies, as well as existing and new labeling methods. The difficulties of extending existing detection methods to hiPSCs are discussed, as well as the potential of hiPSCs to expand GPCR research towards personalized medicine.
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Affiliation(s)
- Gaoxian Chen
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, United States
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, United States
| | - Detlef Obal
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, United States
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, United States
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3
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Liu Z, Cao G, Wu G, Chen T. SCC-FRET: single-cell-based calibration of a FRET system. OPTICS EXPRESS 2022; 30:29063-29073. [PMID: 36299090 DOI: 10.1364/oe.459861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/28/2022] [Indexed: 06/16/2023]
Abstract
Reliable measurements of calibration parameters are crucial for quantitative three-cube Förster resonance energy transfer (FRET) measurements. Here we have developed a single-cell-based calibration method (SCC-FRET), which can simultaneously obtain spectral crosstalk correction parameters (β and δ) and calibration parameters (G and k) of a quantitative FRET system by imaging a cell expressing one kind of standard FRET plasmid with a known FRET efficiency (E) and the donor-to-acceptor concentration ratio (RC). We performed the SCC-FRET method on a three-cube FRET microscopy for the cells expressing C5V, and obtained β = 0.150 ± 0.000, δ = 0.610 ± 0.000, G = 2.840 ± 0.065, and k = 0.847 ± 0.013. These parameters were used to measure the E and RC values of C17V and C32V constructs in living cells and obtained EC17V = 0.382 ± 0.010 and EC32V = 0.311 ± 0.007, RC17V = 1.010 ± 0.023 and RC32V = 1.050 ± 0.022, consistent with the reported values, demonstrating the effectiveness of the the SCC-FRET method. We also performed the SCC-FRET method for the cells with different S/N levels (S/N > 10, 10 > S/N > 3, 3 > S/N > 1, respectively), and obtained consistent system calibration parameters under different S/N levels, indicating excellent robustness. SCC-FRET requires only imaging a cell expressing one kind of standard FRET plasmid for measuring all calibration parameters under identical imaging conditions, rendering the SCC-FRET method extremely convenient, accurate, and robust. The SCC-FRET provides strong support for expanding the biological application of quantitative FRET analysis in living cells.
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Sun H, Zhang C, Yuan Y, Gao L, Zhai S, Chen H, Tang Q, Zhuang Z, Chen T. Automated ExEm-spFRET Microscope. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-8. [PMID: 35184790 DOI: 10.1017/s1431927621013891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Excitation–emission-spectral unmixing-based fluorescence resonance energy transfer (ExEm-spFRET) microscopy exhibits excellent robustness in living cells. We here develop an automatic ExEm-spFRET microscope with 3.04 s of time resolution for a quantitative FRET imaging. The user-friendly interface software has been designed to operate in two modes: administrator and user. Automatic background recognition, subtraction, and cell segmentation were integrated into the software, which enables FRET calibration or measurement in a one-click operation manner. In administrator mode, both correction factors and spectral fingerprints are only calibrated periodically for a stable system. In user mode, quantitative ExEm-spFRET imaging is directly implemented for FRET samples. We implemented quantitative ExEm-spFRET imaging for living cells expressing different tandem constructs (C80Y, C40Y, C10Y, and C4Y, respectively) and obtained consistent results for at least 3 months, demonstrating the stability of our microscope. Next, we investigated Bcl-xL-Bad interaction by using ExEm-spFRET imaging and FRET two-hybrid assay and found that the Bcl-xL-Bad complexes exist mainly in Bad-Bcl-xL trimers in healthy cells and Bad-Bcl-xL2 trimers in apoptotic cells. We also performed time-lapse FRET imaging on our system for living cells expressing Yellow Cameleon 3.6 (YC3.6) to monitor ionomycin-induced rapid extracellular Ca2+ influx with a time interval of 5 s for total 250 s.
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Affiliation(s)
- Han Sun
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
| | - Chenshuang Zhang
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
| | - Ye Yuan
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
| | - Lu Gao
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
| | - Shixian Zhai
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
| | - Hongce Chen
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
| | - Qilin Tang
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
| | - Zhengfei Zhuang
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- SCNU Qingyuan Institutes of Science and Technology Innovation Co., Ltd., Qingyuan511517, China
| | - Tongsheng Chen
- Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou510631, China
- SCNU Qingyuan Institutes of Science and Technology Innovation Co., Ltd., Qingyuan511517, China
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Lin Y, Wang H, Xu J, Huang Y, Gong W, Wang Q, Huang Z, Xie S, Lin J. High spatio-temporal resolution measurement of A 1 R and A 2A R interactions combined with Iem-spFRET and E-FRET methods. JOURNAL OF BIOPHOTONICS 2021; 14:e202100172. [PMID: 34328277 DOI: 10.1002/jbio.202100172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/17/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
A1 R-A2A R heterodimers regulate striatal glutamatergic neurotransmission. However, few researches about kinetics have been reported. Here, we combined Iem-spFRET and E-FRET to investigate the kinetics of A1 R and A2A R interaction. Iem-spFRET obtains the energy transfer efficiency of the whole cell. E-FRET gets energy transfer efficiency with high spatial resolution, whereas, it was prone to biases because background was easily selected due to manual operation. To study the interaction with high spatio-temporal resolution, Iem-spFRET was used to correct the deviation of E-FRET. In this paper, A1 R and A2A R interaction was monitored, and the changes of FRET efficiency of the whole or/and partial cell membrane were described. The results showed that activation of A1 R or A2A R leads to rapid aggregation, inhibition of A1 R or A2A R leads to slow segregation, and the interaction is reversible. These results demonstrated that combination of Iem-spFRET and E-FRET could measure A1 R and A2A R interaction with high spatio-temporal resolution.
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Affiliation(s)
- Yating Lin
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Haoyu Wang
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Jianshu Xu
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Yiming Huang
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Wei Gong
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Qiwen Wang
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Zufang Huang
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Shusen Xie
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Juqiang Lin
- MOE Key Laboratory of OptoElectronic Science and Technology for Medicine and Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou, Fujian, China
- School of Opto-electronic and Communication Engineering, Xiamen University of Technology, Xiamen, Fujian, China
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6
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Liu Z, Luo Z, Chen H, Yin A, Sun H, Zhuang Z, Chen T. Optical section structured illumination-based Förster resonance energy transfer imaging. Cytometry A 2021; 101:264-272. [PMID: 34490985 DOI: 10.1002/cyto.a.24500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/11/2021] [Accepted: 08/31/2021] [Indexed: 01/04/2023]
Abstract
Förster resonance energy transfer (FRET) microscopy is an important tool suitable for studying molecular interactions in living cells. Optical section structured illumination microscopy (OS-SIM), like confocal microscopy, has about 200 nm spatial resolution. In this report, we performed quantitative 3-cube FRET imaging in OS-SIM mode and widefield microscopy (WF) mode, respectively, for living cells expressing FRET constructs consisting of Cerulean (C, donor) and Venus (V, acceptor). OS-SIM images exhibited higher resolution than WF images. Four spectral crosstalk coefficients measured under OS-SIM mode are consistent with those measured under WF mode. Similarly, the system calibration factors G and k measured under OS-SIM mode were consistent with those measured under WF mode. The measured FRET efficiency (E) values of C32V and C17V as well as C5V constructs, standard FRET plasmids, in living Hela cells were E C 32 V OSF = 0.32 ± 0.02 , E C 17 V OSF = 0.38 ± 0.02 , and E C 5 V OSF = 0.45 ± 0.03 , and the measured acceptor-to-donor concentration ratios ( R c ) were R C 32 V OSF = 1.07 ± 0.03 , R C 17 V OSF = 1.09 ± 0.03 , and R C 5 V OSF = 1.02 ± 0.04 , consistent with the reported values. Collectively, our data demonstrates that OS-SIM can be integrated into FRET microscopy to build an OS-SIM-FRET with confocal microscopy-like resolution.
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Affiliation(s)
- Zhi Liu
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China
| | - Zewei Luo
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China
| | - Hongce Chen
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China
| | - Ao Yin
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China
| | - Han Sun
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China
| | - Zhengfei Zhuang
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,SCNU Qingyuan Institute of Science and Technology Innovation Co., Ltd., South China Normal University, Qingyuan, China
| | - Tongsheng Chen
- Key Laboratory of Laser Life Science, Ministry of Education, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong, China.,SCNU Qingyuan Institute of Science and Technology Innovation Co., Ltd., South China Normal University, Qingyuan, China
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7
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sun H, Zhang C, Ma Y, Du M, Chen T. Controlling and online measurement of automatic dual-channel E-FRET microscope. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2019.101585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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8
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Zhang C, Liu Y, Qu W, Su W, Du M, Yang F, Chen T. ExEm-FRET two-hybrid assay: FRET two-hybrid assay based on linear unmixing of excitation-emission spectra. OPTICS EXPRESS 2019; 27:18282-18295. [PMID: 31252774 DOI: 10.1364/oe.27.018282] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
Simultaneous linear unmixing of excitation-emission spectra (ExEm-unmixing)-based fluorescence resonance energy transfer (FRET) two-hybrid assay method, named as ExEm-FRET two-hybrid assay, was developed for evaluating the stoichiometric ratio of macromolecular complexes in living cells. Linear unmixing of the excitation-emission spectra (SDA) of cells obtains the weight factors of donor (WD), acceptor (WA) and acceptor sensitization (WS), yielding ED and EA (donor- and acceptor-centric FRET efficiency) images. ExEm-FRET two-hybrid assay employs pixel-to-pixel titration curves of ED/EA versus the free acceptor (Ca)/donor (Cd) concentration deduced from the three weight factors to obtain EA,max and ED,max (the maximal EA and ED), thus yielding the stoichiometric ratio (EA,max/ED,max) of donor-tagged protein to acceptor-tagged protein.
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9
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Su W, Du M, Lin F, Zhang C, Chen T. Quantitative FRET measurement based on spectral unmixing of donor, acceptor and spontaneous excitation-emission spectra. JOURNAL OF BIOPHOTONICS 2019; 12:e201800314. [PMID: 30414249 DOI: 10.1002/jbio.201800314] [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: 08/21/2018] [Revised: 09/28/2018] [Accepted: 11/06/2018] [Indexed: 06/08/2023]
Abstract
The spontaneous excitation-emission (ExEm) spectrum is introduced to the quantitative mExEm-spFRET methodology we recently developed as a spectral unmixing component for quantitative fluorescence resonance energy transfer measurement, named as SPEES-FRET method. The spectral fingerprints of both donor and acceptor were measured in HepG2 cells with low autofluorescence separately expressing donor and acceptor, and the spontaneous spectral fingerprint of HEK293 cells with strong autofluoresence was measured from blank cells. SPEES-FRET was performed on improved spectrometer-microscope system to measure the FRET efficiency (E) and concentration ratio (R C ) of acceptor to donor vales of FRET tandem plasmids in HEK293 cells, and obtained stable and consistent results with the expected values. Moreover, SPEES-FRET always obtained stable results for the bright and dim cells coexpressing Cerulean and Venus or Cyan Fluorescent Protein (CFP)-Bax and Yellow fluorescent protein (YFP)-Bax, and the E values between CFP-Bax and YFP-Bax were 0.02 for healthy cells and 0.14 for the staurosporine (STS)-treated apoptotic cells. Collectively, SPEES-FRET has very strong robustness against cellular autofluorescence, and thus is applicable to quantitative evaluation on the protein-protein interaction in living cells with strong autofluoresence.
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Affiliation(s)
- Wenhua Su
- MOE Key Laboratory of Laser Life Science & College of Life Science, South China Normal University, Guangzhou, China
| | - Mengyan Du
- MOE Key Laboratory of Laser Life Science & College of Life Science, South China Normal University, Guangzhou, China
| | - Fangrui Lin
- MOE Key Laboratory of Laser Life Science & College of Life Science, South China Normal University, Guangzhou, China
| | - Chenshuang Zhang
- MOE Key Laboratory of Laser Life Science & College of Life Science, South China Normal University, Guangzhou, China
| | - Tongsheng Chen
- MOE Key Laboratory of Laser Life Science & College of Life Science, South China Normal University, Guangzhou, China
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10
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ZHANG C, LIN F, DU M, QU W, MAI Z, QU J, CHEN T. Simultaneous measurement of quantum yield ratio and absorption ratio between acceptor and donor by linearly unmixing excitation-emission spectra. J Microsc 2018; 270:335-342. [DOI: 10.1111/jmi.12687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 01/02/2018] [Accepted: 01/23/2018] [Indexed: 11/29/2022]
Affiliation(s)
- C. ZHANG
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - F. LIN
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - M. DU
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - W. QU
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - Z. MAI
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - J. QU
- Key Laboratory of Optoelectronic Devices; Shenzhen University; Shenzhen China
| | - T. CHEN
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
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11
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Lin F, Du M, Yang F, Wei L, Chen T. Improved spectrometer-microscope for quantitative fluorescence resonance energy transfer measurement based on simultaneous spectral unmixing of excitation and emission spectra. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-10. [PMID: 29313324 DOI: 10.1117/1.jbo.23.1.016006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 12/07/2017] [Indexed: 06/07/2023]
Abstract
Based on our recently developed quantitative fluorescence resonance energy transfer (FRET) measurement method using simultaneous spectral unmixing of excitation and emission spectra (ExEm-spFRET), we here set up an improved spectrometer-microscope (SM) for implementing modified ExEm-spFRET (mExEm-spFRET), in which a system correction factor (fsc) is introduced. Our SM system is very stable for at least six months. Implementation of mExEm-spFRET with four or two excitation wavelengths on SM for single living cells expressing different FRET constructs obtained consistent FRET efficiency (E) and acceptor-donor concentration ratio (Rc) values. We also performed mExEm-spFRET measurement for single living cells coexpressing cyan fluorescent protein (CFP)-Bax and yellow fluorescent protein (YFP)-Bax and found that the E values between CFP-Bax and YFP-Bax were very low (2.2%) and independent of Rc for control cells, indicating that Bax did not exist as homooligomer in healthy cells, but positively proportional to Rc in the case of Rc<1 and kept constant value (25%) when Rc>1 for staurosporine (STS)-treated cells, demonstrating that all Bax formed homooligomer after STS treatment for 6 h.
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Affiliation(s)
- Fangrui Lin
- South China Normal University, MOE Key Laboratory of Laser Life Science and College of Life Science,, China
| | - Mengyan Du
- South China Normal University, MOE Key Laboratory of Laser Life Science and College of Life Science,, China
| | - Fangfang Yang
- South China Normal University, MOE Key Laboratory of Laser Life Science and College of Life Science,, China
| | - Lichun Wei
- South China Normal University, MOE Key Laboratory of Laser Life Science and College of Life Science,, China
| | - Tongsheng Chen
- South China Normal University, MOE Key Laboratory of Laser Life Science and College of Life Science,, China
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12
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DU M, MAI Z, YANG F, LIN F, WEI L, CHEN T. Multichannel wide-field microscopic FRET imaging based on simultaneous spectral unmixing of excitation and emission spectra. J Microsc 2017; 269:66-77. [DOI: 10.1111/jmi.12609] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/24/2017] [Accepted: 07/10/2017] [Indexed: 12/23/2022]
Affiliation(s)
- M. DU
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - Z. MAI
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - F. YANG
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - F. LIN
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - L. WEI
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
| | - T. CHEN
- MOE Key Laboratory of Laser Life Science & College of Life Science; South China Normal University; Guangzhou China
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13
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Várnai P, Gulyás G, Tóth DJ, Sohn M, Sengupta N, Balla T. Quantifying lipid changes in various membrane compartments using lipid binding protein domains. Cell Calcium 2016; 64:72-82. [PMID: 28088320 DOI: 10.1016/j.ceca.2016.12.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/28/2016] [Accepted: 12/29/2016] [Indexed: 11/30/2022]
Abstract
One of the largest challenges in cell biology is to map the lipid composition of the membranes of various organelles and define the exact location of processes that control the synthesis and distribution of lipids between cellular compartments. The critical role of phosphoinositides, low-abundant lipids with rapid metabolism and exceptional regulatory importance in the control of almost all aspects of cellular functions created the need for tools to visualize their localizations and dynamics at the single cell level. However, there is also an increasing need for methods to determine the cellular distribution of other lipids regulatory or structural, such as diacylglycerol, phosphatidic acid, or other phospholipids and cholesterol. This review will summarize recent advances in this research field focusing on the means by which changes can be described in more quantitative terms.
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Affiliation(s)
- Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Gergő Gulyás
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Dániel J Tóth
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, United States; Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Mira Sohn
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, United States
| | - Nivedita Sengupta
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, United States
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, United States.
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Zhang J, Lin F, Chai L, Wei L, Chen T. IIem-spFRET: improved Iem-spFRET method for robust FRET measurement. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:105003. [PMID: 27735016 DOI: 10.1117/1.jbo.21.10.105003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 09/22/2016] [Indexed: 06/06/2023]
Abstract
We recently developed a quantitative Förster resonance energy transfer (FRET) measurement method based on emission-spectral unmixing (Iem-spFRET). We here developed an improved Iem-spFRET method (termed as IIem-spFRET) for more robust FRET measurement in living cells. First, two background (BG) spectral fingerprints measured from blank living cells are introduced to remove BG and autofluorescence. Second, we introduce a ? factor denoting the ratio of two molar extinction coefficient ratios (?) of acceptor to donor at two excitations into IIem-spFRET for direct measurement of the ? values using a tandem construct with unknown FRET efficiency (E). We performed IIem-spFRET on our microscope–spectrometer platform to measure the ? values of Venus (V) to Cerulean (C) and the E values of C32V, CVC, VCV, and VCVV constructs, respectively, in living Huh7 cells. For the C32V or CVC cells, the Iem-spFRET and IIem-spFRET methods measured consistent E values. However, for the cells especially with low expressing levels of VCV or VCVV, the E values measured by Iem-spFRET showed large deviations and fluctuations, whereas the IIem-spFRET method greatly improved the measured E values. Collectively, IIem-spFRET is a powerful and robust tool for quantitatively measuring FRET signal in living cells.
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Affiliation(s)
- Jiang Zhang
- South China Normal University, College of Life Science, MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, Guangzhou 510631, China
| | - Fangrui Lin
- South China Normal University, College of Life Science, MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, Guangzhou 510631, China
| | - Liuying Chai
- South China Normal University, College of Life Science, MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, Guangzhou 510631, China
| | - Lichun Wei
- South China Normal University, College of Life Science, MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, Guangzhou 510631, China
| | - Tongsheng Chen
- South China Normal University, College of Life Science, MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, Guangzhou 510631, China
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