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Yang Q, Miki T. Characterization of peptide-fused protein assemblies in living cells. Methods Enzymol 2024; 697:293-319. [PMID: 38816127 DOI: 10.1016/bs.mie.2024.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Assembly of de novo peptides designed from scratch is in a semi-rational manner and creates artificial supramolecular structures with unique properties. Considering that the functions of various proteins in living cells are highly regulated by their assemblies, building artificial assemblies within cells holds the potential to simulate the functions of natural protein assemblies and engineer cellular activities for controlled manipulation. How can we evaluate the self-assembly of designed peptides in cells? The most effective approach involves the genetic fusion of fluorescent proteins (FPs). Expressing a self-assembling peptide fused with an FP within cells allows for evaluating assemblies through fluorescence signal. When µm-scale assemblies such as condensates are formed, the peptide assemblies can be directly observed by imaging. For sub-µm-scale assemblies, fluorescence correlation spectroscopy analysis is more practical. Additionally, the fluorescence resonance energy transfer (FRET) signal between FPs is valuable evidence of proximity. The decrease in fluorescence anisotropy associated with homo-FRET reveals the properties of self-assembly. Furthermore, by combining two FPs, one acting as a donor and the other as an acceptor, the heteromeric interaction between two different components can be studied through the FRET signal. In this chapter, we provide detailed protocols, from designing and constructing plasmid DNA expressing the peptide-fused protein to analysis of self-assembly in living cells.
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Affiliation(s)
- Qinxuan Yang
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Takayuki Miki
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
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2
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Almeida E Silva G, Galvão Wakui V, Kato L, Marquezin CA. Spectroscopic behavior of bufotenine and bufotenine N-oxide: Solvent and pH effects and interaction with biomembrane models. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184304. [PMID: 38408695 DOI: 10.1016/j.bbamem.2024.184304] [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: 11/21/2023] [Revised: 02/08/2024] [Accepted: 02/20/2024] [Indexed: 02/28/2024]
Abstract
Bufotenine is a fluorescent analog of Dimethyltryptamine (DMT) that has been widely studied due to its psychedelic properties and biological activity. However, little is known about its spectroscopic properties in different media. Thus, we present in this work, for the first time, the spectroscopic behavior of bufotenine and bufotenine N-oxide by means of their fluorescence properties. Both molecules exhibit changes in optical absorption and emission spectra with variations in pH of the medium and in different solvents. Assays in the presence of biomembranes models, like micelles and liposomes, were also performed. In surfactants titration experiments, the spectral shift observed in fluorescence shows the interaction of both molecules with pre-micellar structures and with micelles. Steady state anisotropy measurements show that both bufotenine and bufotenine N-oxide, in the studied concentration range, interact with liposomes without causing changes in the fluidity of the lipid bilayer. These results can be useful in studies that aim at searching for new compounds, inspired by bufotenine and bufotenine N-oxide, with relevant pharmacological activities and also in studies that use these molecules as markers of psychiatric disorders.
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Affiliation(s)
| | - Vinícius Galvão Wakui
- Instituto de Química, Universidade Federal de Goiás, CEP 74690-900, Goiânia, GO, Brazil
| | - Lucília Kato
- Instituto de Química, Universidade Federal de Goiás, CEP 74690-900, Goiânia, GO, Brazil
| | - Cássia A Marquezin
- Instituto de Física, Universidade Federal de Goiás, CEP 74690-900, Goiânia, GO, Brazil.
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3
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Mathur D, Díaz SA, Hildebrandt N, Pensack RD, Yurke B, Biaggne A, Li L, Melinger JS, Ancona MG, Knowlton WB, Medintz IL. Pursuing excitonic energy transfer with programmable DNA-based optical breadboards. Chem Soc Rev 2023; 52:7848-7948. [PMID: 37872857 PMCID: PMC10642627 DOI: 10.1039/d0cs00936a] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Indexed: 10/25/2023]
Abstract
DNA nanotechnology has now enabled the self-assembly of almost any prescribed 3-dimensional nanoscale structure in large numbers and with high fidelity. These structures are also amenable to site-specific modification with a variety of small molecules ranging from drugs to reporter dyes. Beyond obvious application in biotechnology, such DNA structures are being pursued as programmable nanoscale optical breadboards where multiple different/identical fluorophores can be positioned with sub-nanometer resolution in a manner designed to allow them to engage in multistep excitonic energy-transfer (ET) via Förster resonance energy transfer (FRET) or other related processes. Not only is the ability to create such complex optical structures unique, more importantly, the ability to rapidly redesign and prototype almost all structural and optical analogues in a massively parallel format allows for deep insight into the underlying photophysical processes. Dynamic DNA structures further provide the unparalleled capability to reconfigure a DNA scaffold on the fly in situ and thus switch between ET pathways within a given assembly, actively change its properties, and even repeatedly toggle between two states such as on/off. Here, we review progress in developing these composite materials for potential applications that include artificial light harvesting, smart sensors, nanoactuators, optical barcoding, bioprobes, cryptography, computing, charge conversion, and theranostics to even new forms of optical data storage. Along with an introduction into the DNA scaffolding itself, the diverse fluorophores utilized in these structures, their incorporation chemistry, and the photophysical processes they are designed to exploit, we highlight the evolution of DNA architectures implemented in the pursuit of increased transfer efficiency and the key lessons about ET learned from each iteration. We also focus on recent and growing efforts to exploit DNA as a scaffold for assembling molecular dye aggregates that host delocalized excitons as a test bed for creating excitonic circuits and accessing other quantum-like optical phenomena. We conclude with an outlook on what is still required to transition these materials from a research pursuit to application specific prototypes and beyond.
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Affiliation(s)
- Divita Mathur
- Department of Chemistry, Case Western Reserve University, Cleveland OH 44106, USA
| | - Sebastián A Díaz
- Center for Bio/Molecular Science and Engineering, Code 6900, USA.
| | - Niko Hildebrandt
- Department of Chemistry, Seoul National University, Seoul 08826, South Korea
- Department of Engineering Physics, McMaster University, Hamilton, L8S 4L7, Canada
| | - Ryan D Pensack
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Bernard Yurke
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Austin Biaggne
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Lan Li
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
- Center for Advanced Energy Studies, Idaho Falls, ID 83401, USA
| | - Joseph S Melinger
- Electronics Science and Technology Division, Code 6800, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Mario G Ancona
- Electronics Science and Technology Division, Code 6800, U.S. Naval Research Laboratory, Washington, DC 20375, USA
- Department of Electrical and Computer Engineering, Florida State University, Tallahassee, FL 32310, USA
| | - William B Knowlton
- Micron School of Materials Science & Engineering, Boise State University, Boise, ID 83725, USA.
| | - Igor L Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900, USA.
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4
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Babu Manoharan G, Guzmán C, Najumudeen AK, Abankwa D. Detection of Ras nanoclustering-dependent homo-FRET using fluorescence anisotropy measurements. Eur J Cell Biol 2023; 102:151314. [PMID: 37058825 DOI: 10.1016/j.ejcb.2023.151314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/10/2023] [Accepted: 04/10/2023] [Indexed: 04/16/2023] Open
Abstract
The small GTPase Ras is frequently mutated in cancer and a driver of tumorigenesis. The recent years have shown great progress in drug-targeting Ras and understanding how it operates on the plasma membrane. We now know that Ras is non-randomly organized into proteo-lipid complexes on the membrane, called nanoclusters. Nanoclusters contain only a few Ras proteins and are necessary for the recruitment of downstream effectors, such as Raf. If tagged with fluorescent proteins, the dense packing of Ras in nanoclusters can be analyzed by Förster/ fluorescence resonance energy transfer (FRET). Loss of FRET can therefore report on decreased nanoclustering and any process upstream of it, such as Ras lipid modifications and correct trafficking. Thus, cellular FRET screens employing Ras-derived fluorescence biosensors are potentially powerful tools to discover chemical or genetic modulators of functional Ras membrane organization. Here we implement fluorescence anisotropy-based homo-FRET measurements of Ras-derived constructs labelled with only one fluorescent protein on a confocal microscope and a fluorescence plate reader. We show that homo-FRET of both H-Ras- and K-Ras-derived constructs can sensitively report on Ras-lipidation and -trafficking inhibitors, as well as on genetic perturbations of proteins regulating membrane anchorage. By exploiting the switch I/II-binding Ras-dimerizing compound BI-2852, this assay is also suitable to report on the engagement of the K-Ras switch II pocket by small molecules such as AMG 510. Given that homo-FRET only requires one fluorescent protein tagged Ras construct, this approach has significant advantages to create Ras-nanoclustering FRET-biosensor reporter cell lines, as compared to the more common hetero-FRET approaches.
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Affiliation(s)
- Ganesh Babu Manoharan
- Cancer Cell Biology and Drug Discovery group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Camilo Guzmán
- Euro-BioImaging ERIC, Statutory Seat, Turku, Finland
| | - Arafath Kaja Najumudeen
- Institute of Biotechnology, HiLIFE Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Daniel Abankwa
- Cancer Cell Biology and Drug Discovery group, Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg.
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5
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Starr CA, Nair S, Huang SY, Hagan MF, Jacobson SC, Zlotnick A. Engineering Metastability into a Virus-like Particle to Enable Triggered Dissociation. J Am Chem Soc 2023; 145:2322-2331. [PMID: 36651799 PMCID: PMC10018796 DOI: 10.1021/jacs.2c10937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
For a virus-like particle (VLP) to serve as a delivery platform, the VLP must be able to release its cargo in response to a trigger. Here, we use a chemical biology approach to destabilize a self-assembling capsid for a subsequent triggered disassembly. We redesigned the dimeric hepatitis B virus (HBV) capsid protein (Cp) with two differentially addressable cysteines, C150 for reversibly crosslinking the capsid and C124 to react with a destabilizing moiety. The resulting construct, Cp150-V124C, assembles into icosahedral, 120-dimer VLPs that spontaneously crosslink via the C-terminal C150, leaving C124 buried at a dimer-dimer interface. The VLP is driven into a metastable state when C124 is reacted with the bulky fluorophore, maleimidyl BoDIPY-FL. The resulting VLP is stable until exposed to modest, physiologically relevant concentrations of reducing agent. We observe dissociation with FRET relaxation of polarization, size exclusion chromatography, and resistive-pulse sensing. Dissociation is slow, minutes to hours, with a characteristic lag phase. Mathematical modeling based on the presence of a nucleation step predicts disassembly dynamics that are consistent with experimental observations. VLPs transfected into hepatoma cells show similar dissociation behavior. These results suggest a generalizable strategy for designing a VLP that can release its contents in an environmentally responsive reaction.
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Affiliation(s)
- Caleb A. Starr
- Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405 USA
| | - Smita Nair
- Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405 USA
- current address: Door Pharmaceuticals, Bloomington, IN 47401 USA
| | - Sheng-Yuan Huang
- Department of Chemistry, Indiana University, Bloomington, IN 47405 USA
| | - Michael F. Hagan
- Martin Fisher School of Physics, Brandeis University, Waltham, MA 02454 USA
| | | | - Adam Zlotnick
- Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405 USA
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6
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Molecular Events behind the Selectivity and Inactivation Properties of Model NaK-Derived Ion Channels. Int J Mol Sci 2022; 23:ijms23169246. [PMID: 36012519 PMCID: PMC9409022 DOI: 10.3390/ijms23169246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/10/2022] [Accepted: 08/14/2022] [Indexed: 11/17/2022] Open
Abstract
Y55W mutants of non-selective NaK and partly K+-selective NaK2K channels have been used to explore the conformational dynamics at the pore region of these channels as they interact with either Na+ or K+. A major conclusion is that these channels exhibit a remarkable pore conformational flexibility. Homo-FRET measurements reveal a large change in W55–W55 intersubunit distances, enabling the selectivity filter (SF) to admit different species, thus, favoring poor or no selectivity. Depending on the cation, these channels exhibit wide-open conformations of the SF in Na+, or tight induced-fit conformations in K+, most favored in the four binding sites containing NaK2K channels. Such conformational flexibility seems to arise from an altered pattern of restricting interactions between the SF and the protein scaffold behind it. Additionally, binding experiments provide clues to explain such poor selectivity. Compared to the K+-selective KcsA channel, these channels lack a high affinity K+ binding component and do not collapse in Na+. Thus, they cannot properly select K+ over competing cations, nor reject Na+ by collapsing, as K+-selective channels do. Finally, these channels do not show C-type inactivation, likely because their submillimolar K+ binding affinities prevent an efficient K+ loss from their SF, thus favoring permanently open channel states.
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7
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Duan Z, Li K, Duan W, Zhang J, Xing J. Probing membrane protein interactions and signaling molecule homeostasis in plants by Förster resonance energy transfer analysis. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:68-77. [PMID: 34610124 DOI: 10.1093/jxb/erab445] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Membrane proteins have key functions in signal transduction, transport, and metabolism. Therefore, deciphering the interactions between membrane proteins provides crucial information on signal transduction and the spatiotemporal organization of protein complexes. However, detecting the interactions and behaviors of membrane proteins in their native environments remains difficult. Förster resonance energy transfer (FRET) is a powerful tool for quantifying the dynamic interactions and assembly of membrane proteins without disrupting their local environment, supplying nanometer-scale spatial information and nanosecond-scale temporal information. In this review, we briefly introduce the basic principles of FRET and assess the current state of progress in the development of new FRET techniques (such as FRET-FLIM, homo-FRET, and smFRET) for the analysis of plant membrane proteins. We also describe the various FRET-based biosensors used to quantify the homeostasis of signaling molecules and the active state of kinases. Furthermore, we summarize recent applications of these advanced FRET sensors in probing membrane protein interactions, stoichiometry, and protein clustering, which have shed light on the complex biological functions of membrane proteins in living plant cells.
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Affiliation(s)
- Zhikun Duan
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Kaiwen Li
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Wenwen Duan
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Junli Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Jingjing Xing
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
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8
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Díaz-García C, Renart ML, Poveda JA, Giudici AM, González-Ros JM, Prieto M, Coutinho A. Probing the Structural Dynamics of the Activation Gate of KcsA Using Homo-FRET Measurements. Int J Mol Sci 2021; 22:ijms222111954. [PMID: 34769384 PMCID: PMC8584343 DOI: 10.3390/ijms222111954] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/18/2021] [Accepted: 10/29/2021] [Indexed: 12/16/2022] Open
Abstract
The allosteric coupling between activation and inactivation processes is a common feature observed in K+ channels. Particularly, in the prokaryotic KcsA channel the K+ conduction process is controlled by the inner gate, which is activated by acidic pH, and by the selectivity filter (SF) or outer gate, which can adopt non-conductive or conductive states. In a previous study, a single tryptophan mutant channel (W67 KcsA) enabled us to investigate the SF dynamics using time-resolved homo-Förster Resonance Energy Transfer (homo-FRET) measurements. Here, the conformational changes of both gates were simultaneously monitored after labelling the G116C position with tetramethylrhodamine (TMR) within a W67 KcsA background. At a high degree of protein labeling, fluorescence anisotropy measurements showed that the pH-induced KcsA gating elicited a variation in the homo-FRET efficiency among the conjugated TMR dyes (TMR homo-FRET), while the conformation of the SF was simultaneously tracked (W67 homo-FRET). The dependence of the activation pKa of the inner gate with the ion occupancy of the SF unequivocally confirmed the allosteric communication between the two gates of KcsA. This simple TMR homo-FRET based ratiometric assay can be easily extended to study the conformational dynamics associated with the gating of other ion channels and their modulation.
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Affiliation(s)
- Clara Díaz-García
- iBB, Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; (C.D.-G.); (M.P.)
- Associate Laboratory i4HB, Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Maria Lourdes Renart
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche, Universidad Miguel Hernández, 03202 Elche, Spain; (J.A.P.); (A.M.G.); (J.M.G.-R.)
- Correspondence: (M.L.R.); (A.C.)
| | - José Antonio Poveda
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche, Universidad Miguel Hernández, 03202 Elche, Spain; (J.A.P.); (A.M.G.); (J.M.G.-R.)
| | - Ana Marcela Giudici
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche, Universidad Miguel Hernández, 03202 Elche, Spain; (J.A.P.); (A.M.G.); (J.M.G.-R.)
| | - José M. González-Ros
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche, Universidad Miguel Hernández, 03202 Elche, Spain; (J.A.P.); (A.M.G.); (J.M.G.-R.)
| | - Manuel Prieto
- iBB, Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; (C.D.-G.); (M.P.)
- Associate Laboratory i4HB, Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Ana Coutinho
- iBB, Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; (C.D.-G.); (M.P.)
- Associate Laboratory i4HB, Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
- Correspondence: (M.L.R.); (A.C.)
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9
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Pal S, Koeppe RE, Chattopadhyay A. Membrane electrostatics sensed by tryptophan anchors in hydrophobic model peptides depends on non-aromatic interfacial amino acids: implications in hydrophobic mismatch. Faraday Discuss 2021; 232:330-346. [PMID: 34549729 DOI: 10.1039/d0fd00065e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
WALPs are synthetic α-helical membrane-spanning peptides that constitute a well-studied system for exploring hydrophobic mismatch. These peptides represent a simplified consensus motif for transmembrane domains of intrinsic membrane proteins due to their hydrophobic core of alternating leucine and alanine flanked by membrane-anchoring aromatic tryptophan residues. Although the modulation of mismatch responses in WALPs by tryptophan anchors has been reported earlier, there have been limited attempts to utilize the intrinsic tryptophan fluorescence of this class of peptides in mismatch sensors. We have previously shown, utilizing the red edge excitation shift (REES) approach, that interfacial WALP tryptophan residues in fluid phase bilayers experience a dynamically constrained membrane microenvironment. Interestingly, emerging reports suggest the involvement of non-aromatic interfacially localized residues in modulating local structure and dynamics in WALP analogs. In this backdrop, we have explored the effect of interfacial amino acids, such as lysine (in KWALPs) and glycine (in GWALPs), on the tryptophan microenvironment of WALP analogs in zwitterionic and negatively charged membranes. We show that interfacial tryptophans in KWALP and GWALP experience a more restricted microenvironment, as reflected in the substantial increase in magnitude of REES and apparent rotational correlation time, relative to those in WALP in zwitterionic membranes. Interestingly, in contrast to WALP, the tryptophan anchors in KWALP and GWALP appear insensitive to the presence of negatively charged lipids in the membrane. These results reveal a subtle interplay between non-aromatic flanking residues in transmembrane helices and negatively charged lipids at the membrane interface, which could modulate the membrane microenvironment experienced by interfacially localized tryptophan residues. Since interfacial tryptophans are known to influence mismatch responses in WALPs, our results highlight the possibility of utilizing the fluorescence signatures of tryptophans in membrane proteins or model peptides such as WALP as markers for assessing protein responses to hydrophobic mismatch. More importantly, these results constitute one of the first reports on the influence of lipid headgroup charge in fine-tuning hydrophobic mismatch in membrane bilayers, thereby enriching the existing framework of hydrophobic mismatch.
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Affiliation(s)
- Sreetama Pal
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India. .,CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.,Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Roger E Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas, AR 72701, USA
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India. .,Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
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10
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Habif M, Corbat AA, Silberberg M, Grecco HE. CASPAM: A Triple-Modality Biosensor for Multiplexed Imaging of Caspase Network Activity. ACS Sens 2021; 6:2642-2653. [PMID: 34191492 DOI: 10.1021/acssensors.1c00554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Understanding signal propagation across biological networks requires to simultaneously monitor the dynamics of several nodes to uncover correlations masked by inherent intercellular variability. To monitor the enzymatic activity of more than two components over short time scales has proven challenging. Exploiting the narrow spectral width of homo-FRET-based biosensors, up to three activities can be imaged through fluorescence polarization anisotropy microscopy. We introduce Caspase Activity Sensor by Polarization Anisotropy Multiplexing (CASPAM) a single-plasmid triple-modality reporter of key nodes of the apoptotic network. Apoptosis provides an ideal molecular framework to study interactions between its three composing pathways (intrinsic, extrinsic, and effector). We characterized the biosensor performance and demonstrated the advantages that equimolar expression has in both simplifying experimental procedure and reducing observable variation, thus enabling robust data-driven modeling. Tools like CASPAM become essential to analyze molecular pathways where multiple nodes need to be simultaneously monitored.
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Affiliation(s)
- Martín Habif
- Department of Physics, FCEN, University of Buenos Aires and IFIBA, CONICET, Buenos Aires C1428EHA, Argentina
| | - Agustín A. Corbat
- Department of Physics, FCEN, University of Buenos Aires and IFIBA, CONICET, Buenos Aires C1428EHA, Argentina
| | - Mauro Silberberg
- Department of Physics, FCEN, University of Buenos Aires and IFIBA, CONICET, Buenos Aires C1428EHA, Argentina
| | - Hernán E. Grecco
- Department of Physics, FCEN, University of Buenos Aires and IFIBA, CONICET, Buenos Aires C1428EHA, Argentina
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund 44227, Germany
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11
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Pal S, Chakraborty H, Chattopadhyay A. Lipid Headgroup Charge Controls Melittin Oligomerization in Membranes: Implications in Membrane Lysis. J Phys Chem B 2021; 125:8450-8459. [PMID: 34254509 DOI: 10.1021/acs.jpcb.1c02499] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Melittin, a hemolytic peptide present in bee venom, represents one of the most well-studied amphipathic antimicrobial peptides, particularly in terms of its membrane interaction and activity. Nevertheless, no consensus exists on the oligomeric state of membrane-bound melittin. We previously reported on the differential microenvironments experienced by melittin in zwitterionic and negatively charged phospholipid membranes. In this work, we explore the role of negatively charged lipids in the oligomerization of membrane-bound melittin (labeled with 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)) utilizing a quantitative photobleaching homo-FRET assay. Our results show that the presence of negatively charged lipids decreases melittin oligomeric size to ∼50% of that observed in zwitterionic membranes. This is possibly due to differential energetics of binding of the peptide monomer to membranes of different compositions and could explain the reduced lytic activity yet tighter binding of melittin in negatively charged membranes. These results constitute one of the first experimental observations on the role of phospholipid headgroup charge in the oligomerization of melittin in membranes and is relevant in light of previous apparently contradictory reports on oligomerization of membrane-bound melittin. Our results highlight the synergistic interplay of peptide-membrane binding events and peptide oligomerization in modulating the organization, dynamics, and function of amphipathic α-helical peptides.
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Affiliation(s)
- Sreetama Pal
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.,Academy of Scientific and Innovative Research, Ghaziabad 201 002, India.,CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
| | - Hirak Chakraborty
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.,School of Chemistry, Sambalpur University, Burla, Odisha 768 019, India
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.,Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
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12
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Shepherd JW, Payne-Dwyer AL, Lee JE, Syeda A, Leake MC. Combining single-molecule super-resolved localization microscopy with fluorescence polarization imaging to study cellular processes. JPHYS PHOTONICS 2021. [DOI: 10.1088/2515-7647/ac015d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Super-resolution microscopy has catalyzed valuable insights into the sub-cellular, mechanistic details of many different biological processes across a wide range of cell types. Fluorescence polarization spectroscopy tools have also enabled important insights into cellular processes through identifying orientational changes of biological molecules typically at an ensemble level. Here, we combine these two biophysical methodologies in a single home-made instrument to enable the simultaneous detection of orthogonal fluorescence polarization signals from single fluorescent protein molecules used as common reporters on the localization of proteins in cellular processes. These enable measurement of spatial location to a super-resolved precision better than the diffraction-limited optical resolution, as well as estimation of molecular stoichiometry based on the brightness of individual fluorophores. In this innovation we have adapted a millisecond timescale microscope used for single-molecule detection to enable splitting of fluorescence polarization emissions into two separate imaging channels for s- and p-polarization signals, which are imaged onto separate halves of the same high sensitivity back-illuminated CMOS camera detector. We applied this fluorescence polarization super-resolved imaging modality to a range of test fluorescent samples relevant to the study of biological processes, including purified monomeric green fluorescent protein, single combed DNA molecules, and protein assemblies and complexes from live Escherichia coli and Saccharomyces cerevisiae cells. Our findings are qualitative but demonstrate promise in showing how fluorescence polarization and super-resolved localization microscopy can be combined on the same sample to enable simultaneous measurements of polarization and stoichiometry of tracked molecular complexes, as well as the translational diffusion coefficient.
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Arumugam S, Schmieder S, Pezeshkian W, Becken U, Wunder C, Chinnapen D, Ipsen JH, Kenworthy AK, Lencer W, Mayor S, Johannes L. Ceramide structure dictates glycosphingolipid nanodomain assembly and function. Nat Commun 2021; 12:3675. [PMID: 34135326 PMCID: PMC8209009 DOI: 10.1038/s41467-021-23961-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 05/28/2021] [Indexed: 02/08/2023] Open
Abstract
Gangliosides in the outer leaflet of the plasma membrane of eukaryotic cells are essential for many cellular functions and pathogenic interactions. How gangliosides are dynamically organized and how they respond to ligand binding is poorly understood. Using fluorescence anisotropy imaging of synthetic, fluorescently labeled GM1 gangliosides incorporated into the plasma membrane of living cells, we found that GM1 with a fully saturated C16:0 acyl chain, but not with unsaturated C16:1 acyl chain, is actively clustered into nanodomains, which depends on membrane cholesterol, phosphatidylserine and actin. The binding of cholera toxin B-subunit (CTxB) leads to enlarged membrane domains for both C16:0 and C16:1, owing to binding of multiple GM1 under a toxin, and clustering of CTxB. The structure of the ceramide acyl chain still affects these domains, as co-clustering with the glycosylphosphatidylinositol (GPI)-anchored protein CD59 occurs only when GM1 contains the fully saturated C16:0 acyl chain, and not C16:1. Thus, different ceramide species of GM1 gangliosides dictate their assembly into nanodomains and affect nanodomain structure and function, which likely underlies many endogenous cellular processes.
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Affiliation(s)
- Senthil Arumugam
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France
- National Centre for Biological Sciences (NCBS), Bangalore, India
- Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC, Australia
- European Molecular Biological Laboratory Australia (EMBL Australia), Monash University, Clayton/ Melbourne, VIC, Australia
| | - Stefanie Schmieder
- Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Weria Pezeshkian
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Ulrike Becken
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France
| | - Christian Wunder
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France
| | - Dan Chinnapen
- Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - John Hjort Ipsen
- MEMPHYS/PhyLife, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, Denmark
| | - Anne K Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
| | - Wayne Lencer
- Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Harvard Digestive Diseases Center, Boston, MA, USA
| | - Satyajit Mayor
- National Centre for Biological Sciences (NCBS), Bangalore, India.
| | - Ludger Johannes
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France.
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14
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Kulenkampff K, Wolf Perez AM, Sormanni P, Habchi J, Vendruscolo M. Quantifying misfolded protein oligomers as drug targets and biomarkers in Alzheimer and Parkinson diseases. Nat Rev Chem 2021; 5:277-294. [PMID: 37117282 DOI: 10.1038/s41570-021-00254-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2021] [Indexed: 02/06/2023]
Abstract
Protein misfolding and aggregation are characteristic of a wide range of neurodegenerative disorders, including Alzheimer and Parkinson diseases. A hallmark of these diseases is the aggregation of otherwise soluble and functional proteins into amyloid aggregates. Although for many decades such amyloid deposits have been thought to be responsible for disease progression, it is now increasingly recognized that the misfolded protein oligomers formed during aggregation are, instead, the main agents causing pathological processes. These oligomers are transient and heterogeneous, which makes it difficult to detect and quantify them, generating confusion about their exact role in disease. The lack of suitable methods to address these challenges has hampered efforts to investigate the molecular mechanisms of oligomer toxicity and to develop oligomer-based diagnostic and therapeutic tools to combat protein misfolding diseases. In this Review, we describe methods to quantify misfolded protein oligomers, with particular emphasis on diagnostic applications as disease biomarkers and on therapeutic applications as target biomarkers. The development of these methods is ongoing, and we discuss the challenges that remain to be addressed to establish measurement tools capable of overcoming existing limitations and to meet present needs.
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15
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Myšková J, Rybakova O, Brynda J, Khoroshyy P, Bondar A, Lazar J. Directionality of light absorption and emission in representative fluorescent proteins. Proc Natl Acad Sci U S A 2020; 117:32395-32401. [PMID: 33273123 PMCID: PMC7768707 DOI: 10.1073/pnas.2017379117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/30/2020] [Indexed: 12/13/2022] Open
Abstract
Fluorescent molecules are like antennas: The rate at which they absorb light depends on their orientation with respect to the incoming light wave, and the apparent intensity of their emission depends on their orientation with respect to the observer. However, the directions along which the most important fluorescent molecules in biology, fluorescent proteins (FPs), absorb and emit light are generally not known. Our optical and X-ray investigations of FP crystals have now allowed us to determine the molecular orientations of the excitation and emission transition dipole moments in the FPs mTurquoise2, eGFP, and mCherry, and the photoconvertible FP mEos4b. Our results will allow using FP directionality in studies of molecular and biological processes, but also in development of novel bioengineering and bioelectronics applications.
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Affiliation(s)
- Jitka Myšková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Olga Rybakova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
- Institute of Microbiology, Czech Academy of Sciences, 37333 Nové Hrady, Czech Republic
| | - Jiří Brynda
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
- Institute of Molecular Genetics, Czech Academy of Sciences, 14220 Prague 4, Czech Republic
| | - Petro Khoroshyy
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
- Institute of Microbiology, Czech Academy of Sciences, 37333 Nové Hrady, Czech Republic
| | - Alexey Bondar
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
- Institute of Microbiology, Czech Academy of Sciences, 37333 Nové Hrady, Czech Republic
| | - Josef Lazar
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic;
- Institute of Microbiology, Czech Academy of Sciences, 37333 Nové Hrady, Czech Republic
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16
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Abstract
Peroxiredoxins are most central to the cellular adaptation against oxidative stress. They act as oxidant scavengers, stress sensors, transmitters of signals, and chaperones, and they possess a unique quaternary switch that is intimately related to these functions. However, so far it has not been possible to monitor peroxiredoxin structural changes in the intact cellular environment. This study presents genetically encoded probes, based on homo-FRET (Förster resonance energy transfer between identical fluorophores) fluorescence polarization, that allow following these quaternary changes in real time, in living cells. We envisage that these probes can be used to address a broad range of questions related to the function of peroxiredoxins. Peroxiredoxins are central to cellular redox homeostasis and signaling. They serve as peroxide scavengers, sensors, signal transducers, and chaperones, depending on conditions and context. Typical 2-Cys peroxiredoxins are known to switch between different oligomeric states, depending on redox state, pH, posttranslational modifications, and other factors. Quaternary states and their changes are closely connected to peroxiredoxin activity and function but so far have been studied, almost exclusively, outside the context of the living cell. Here we introduce the use of homo-FRET (Förster resonance energy transfer between identical fluorophores) fluorescence polarization to monitor dynamic changes in peroxiredoxin quaternary structure inside the crowded environment of living cells. Using the approach, we confirm peroxide- and thioredoxin-related quaternary transitions to take place in cellulo and observe that the relationship between dimer–decamer transitions and intersubunit disulfide bond formation is more complex than previously thought. Furthermore, we demonstrate the use of the approach to compare different peroxiredoxin isoforms and to identify mutations and small molecules affecting the oligomeric state inside cells. Mutagenesis experiments reveal that the dimer–decamer equilibrium is delicately balanced and can be shifted by single-atom structural changes. We show how to use this insight to improve the design of peroxiredoxin-based redox biosensors.
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Povedailo VA, Lysenko IL, Tikhomirov SA, Yakovlev DL, Tsybulsky DA, Kruhlik AS, Fan F, Martynenko-Makaev YV, Sharko OL, Duong PV, Minh PH, Shmanai VV. Fluorescent Properties of Carboxyfluorescein Bifluorophores. J Fluoresc 2020; 30:629-635. [PMID: 32300977 DOI: 10.1007/s10895-020-02535-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 04/02/2020] [Indexed: 11/24/2022]
Abstract
Bright fluorescent probes with enhanced intensities in the fluorescein channel are of great value for plenty of biological applications. To design effective probes one should introduce as many as possible fluorophores to the biomolecule while leaving its native structure as intact as possible. To reach this compromise, we designed and synthesized fluorescein bifluorophores on the 3,5-diaminobenzoic acid scaffold, which allows for insertion of two fluorophores at one modification site of a biomolecule. Rigid structure of the branching linker group allows to minimize self-quenching the fluorophores. However, despite the structure similarities of fluorescein isomers (5-FAM and 6-FAM), different photophysical behavior was observed for the corresponding bifluorophores. Here we made efforts to get insight into these effects with the focus on the media viscosity impact.
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Affiliation(s)
- Vladimir A Povedailo
- B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68 Nezavisimost' Ave, Minsk, 220072, Belarus
| | - Ivan L Lysenko
- Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 13 Surganova str, 220072, Minsk, Belarus
| | - Sergei A Tikhomirov
- B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68 Nezavisimost' Ave, Minsk, 220072, Belarus
| | - Dmitrii L Yakovlev
- B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68 Nezavisimost' Ave, Minsk, 220072, Belarus
| | - Dmitry A Tsybulsky
- Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 13 Surganova str, 220072, Minsk, Belarus
| | - Aliaksandr S Kruhlik
- Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 13 Surganova str, 220072, Minsk, Belarus
| | - Fan Fan
- Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 13 Surganova str, 220072, Minsk, Belarus
| | - Yury V Martynenko-Makaev
- Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 13 Surganova str, 220072, Minsk, Belarus
| | - Olga L Sharko
- Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 13 Surganova str, 220072, Minsk, Belarus
| | - Pham V Duong
- Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Ba Dinh, Hanoi, Vietnam
| | - Pham H Minh
- Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Ba Dinh, Hanoi, Vietnam
| | - Vadim V Shmanai
- Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, 13 Surganova str, 220072, Minsk, Belarus.
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18
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Zhu X, Tang R, Wang S, Chen X, Hu J, Lei C, Huang Y, Wang H, Nie Z, Yao S. Protein@Inorganic Nanodumpling System for High-Loading Protein Delivery with Activatable Fluorescence and Magnetic Resonance Bimodal Imaging Capabilities. ACS NANO 2020; 14:2172-2182. [PMID: 31990525 DOI: 10.1021/acsnano.9b09024] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Efficient protein delivery into the target cell is highly desirable for protein therapeutics. Current approaches for protein delivery commonly suffer from low-loading protein capacity, poor specificity for target cells, and invisible protein release. Herein, we report a protein@inorganic nanodumpling (ND) system as an intracellular protein delivery platform. Similar to a traditional Chinese food, the dumpling, ND consists of a protein complex "filling" formed by metal-ion-directed self-assembly of protein cargos fused to histidine-rich green fluorescent proteins (H39GFPs), which are further encapsulated by an external surface "wrapper" of manganese dioxide (MnO2) via in situ biomineralization. This ND structure allows for a high loading capacity (>63 wt %) for protein cargos with enhanced stability. NDs can be targeted and internalized into cancer cells specifically through folic acid receptors by surface-tailored folic acid. The protein cargo release is in a bistimuli-responsive manner, triggered by an either reductive or acidic intracellular microenvironment. Moreover, the MnO2 nanowrapper is an efficient fluorescence quencher for inner fused GFPs and also a "switch-on" magnetic resonance imaging (MRI) agent via triggered release of Mn2+ ions, which enables activatable fluorescence/MRI bimodal imaging of protein release. Finally, the ND is highly potent and specific to deliver functional protein ribonuclease A (RNase A) into cultured target cells and the tumor site in a xenografted mouse model, eliminating the tumor cells with high therapeutic efficacy. Our approach provides a promising alternative to advance protein-based cancer therapeutics.
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Affiliation(s)
- Xiaohua Zhu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering , Hunan Normal University , Changsha 410081 , P. R. China
| | - Rui Tang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
| | - Shigong Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
| | - Xiaoye Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
| | - Jiajun Hu
- College of Biology , Hunan University , Changsha 410082 , P. R. China
| | - Chunyang Lei
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
| | - Yan Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
| | - Honghui Wang
- College of Biology , Hunan University , Changsha 410082 , P. R. China
| | - Zhou Nie
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
| | - Shouzhuo Yao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology , Hunan University , Changsha 410082 , P. R. China
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19
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Vinegoni C, Feruglio PF, Gryczynski I, Mazitschek R, Weissleder R. Fluorescence anisotropy imaging in drug discovery. Adv Drug Deliv Rev 2019; 151-152:262-288. [PMID: 29410158 PMCID: PMC6072632 DOI: 10.1016/j.addr.2018.01.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 01/29/2018] [Accepted: 01/30/2018] [Indexed: 12/15/2022]
Abstract
Non-invasive measurement of drug-target engagement can provide critical insights in the molecular pharmacology of small molecule drugs. Fluorescence polarization/fluorescence anisotropy measurements are commonly employed in protein/cell screening assays. However, the expansion of such measurements to the in vivo setting has proven difficult until recently. With the advent of high-resolution fluorescence anisotropy microscopy it is now possible to perform kinetic measurements of intracellular drug distribution and target engagement in commonly used mouse models. In this review we discuss the background, current advances and future perspectives in intravital fluorescence anisotropy measurements to derive pharmacokinetic and pharmacodynamic measurements in single cells and whole organs.
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Affiliation(s)
- Claudio Vinegoni
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Paolo Fumene Feruglio
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy
| | - Ignacy Gryczynski
- University of North Texas Health Science Center, Institute for Molecular Medicine, Fort Worth, TX, United States
| | - Ralph Mazitschek
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Ralph Weissleder
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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20
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Savill KJ, Klug MT, Milot RL, Snaith HJ, Herz LM. Charge-Carrier Cooling and Polarization Memory Loss in Formamidinium Tin Triiodide. J Phys Chem Lett 2019; 10:6038-6047. [PMID: 31545045 DOI: 10.1021/acs.jpclett.9b02353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Reports of slow charge-carrier cooling in hybrid metal halide perovskites have prompted hopes of achieving higher photovoltaic cell voltages through hot-carrier extraction. However, observations of long-lived hot charge carriers even at low photoexcitation densities and an orders-of-magnitude spread in reported cooling times have been challenging to explain. Here we present ultrafast time-resolved photoluminescence measurements on formamidinum tin triiodide, showing fast initial cooling over tens of picoseconds and demonstrating that a perceived secondary regime of slower cooling instead derives from electronic relaxation, state-filling, and recombination in the presence of energetic disorder. We identify limitations of some widely used approaches to determine charge-carrier temperature and make use of an improved model which accounts for the full photoluminescence line shape. Further, we do not find any persistent polarization anisotropy in FASnI3 within 270 fs after excitation, indicating that excited carriers rapidly lose both polarization memory and excess energy through interactions with the perovskite lattice.
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Affiliation(s)
- Kimberley J Savill
- Department of Physics , University of Oxford , Clarendon Laboratory, Parks Road , Oxford OX1 3PU , U.K
| | - Matthew T Klug
- Department of Physics , University of Oxford , Clarendon Laboratory, Parks Road , Oxford OX1 3PU , U.K
| | - Rebecca L Milot
- Department of Physics , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Henry J Snaith
- Department of Physics , University of Oxford , Clarendon Laboratory, Parks Road , Oxford OX1 3PU , U.K
| | - Laura M Herz
- Department of Physics , University of Oxford , Clarendon Laboratory, Parks Road , Oxford OX1 3PU , U.K
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21
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Wilhelm P, Vogelsang J, Höger S, Lupton JM. Homo-FRET in π-Conjugated Polygons: Intermediate-Strength Dipole-Dipole Coupling Makes Energy Transfer Reversible. NANO LETTERS 2019; 19:5483-5488. [PMID: 31294999 DOI: 10.1021/acs.nanolett.9b01998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The concept of homo-FRET is often used to describe energy transfer between like chromophores of molecular aggregates such as in π-conjugated polymers. Homo-FRET is revealed by a dynamic depolarization in fluorescence but strictly only applies to the limit of weak dipole-dipole coupling, where energy transfer occurs on time scales much longer than those of nuclear relaxation. By considering the polarization anisotropy of photoluminescence emission and excitation of model multichromophoric aggregates on the single-molecule level, we demonstrate the transition of energy-transfer dynamics from the case of weak coupling to that of strong coupling, revealing the elusive regime of intermediate-strength coupling where energy transfer between degenerate donor and acceptor chromophores becomes reversible so that information on the excitation route of the emitting chromophore is lost.
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Affiliation(s)
- Philipp Wilhelm
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , Universitätsstrasse 31 , 93053 Regensburg , Germany
| | - Jan Vogelsang
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , Universitätsstrasse 31 , 93053 Regensburg , Germany
| | - Sigurd Höger
- Kekulé-Institut für Organische Chemie und Biochemie , Universität Bonn , Gerhard-Domagk-Straße 1 , 53121 Bonn , Germany
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , Universitätsstrasse 31 , 93053 Regensburg , Germany
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22
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Petkov BK, Gellen TA, Farfan CA, Carbery WP, Hetzler BE, Trauner D, Li X, Glover WJ, Ulness DJ, Turner DB. Two-Dimensional Electronic Spectroscopy Reveals the Spectral Dynamics of Förster Resonance Energy Transfer. Chem 2019. [DOI: 10.1016/j.chempr.2019.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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23
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Camacho R, Täuber D, Scheblykin IG. Fluorescence Anisotropy Reloaded-Emerging Polarization Microscopy Methods for Assessing Chromophores' Organization and Excitation Energy Transfer in Single Molecules, Particles, Films, and Beyond. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1805671. [PMID: 30721532 DOI: 10.1002/adma.201805671] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/12/2018] [Indexed: 06/09/2023]
Abstract
Fluorescence polarization is widely used to assess the orientation/rotation of molecules, and the excitation energy transfer between closely located chromophores. Emerging since the 1990s, single molecule fluorescence spectroscopy and imaging stimulate the application of light polarization for studying molecular organization and energy transfer beyond ensemble averaging. Here, traditional fluorescence polarization and linear dichroism methods used for bulk samples are compared with techniques specially developed for, or inspired by, single molecule fluorescence spectroscopy. Techniques for assessing energy transfer in anisotropic samples, where the traditional fluorescence anisotropy framework is not readily applicable, are discussed in depth. It is shown that the concept of a polarization portrait and the single funnel approximation can lay the foundation for alternative energy transfer metrics. Examples ranging from fundamental studies of photoactive materials (conjugated polymers, light-harvesting aggregates, and perovskite semiconductors) to Förster resonant energy transfer (FRET)-based biomedical imaging are presented. Furthermore, novel uses of light polarization for super-resolution optical imaging are mentioned as well as strategies for avoiding artifacts in polarization microscopy.
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Affiliation(s)
- Rafael Camacho
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Daniela Täuber
- Chemical Physics and NanoLund, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
- Biopolarisation, Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745, Jena, Germany
- Institute of Solid State Physics, FSU Jena, Helmholtzweg 3, D-07743, Jena, Germany
| | - Ivan G Scheblykin
- Chemical Physics and NanoLund, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
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Ströhl F, Kaminski CF. A concept for single-shot volumetric fluorescence imaging via orthogonally polarized excitation lattices. Sci Rep 2019; 9:6425. [PMID: 31015487 PMCID: PMC6478832 DOI: 10.1038/s41598-019-42743-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/08/2019] [Indexed: 11/08/2022] Open
Abstract
The deconvolution of widefield fluorescence images provides only guesses of spatial frequency information along the optical axis due to the so called missing cone in the optical transfer function. Retaining the single-shot imaging speed of deconvolution microscopy while gaining access to missing cone information is thus highly desirable for microscopy of volumetric samples. Here, we present a concept that superimposes two orthogonally polarized excitation lattices with a phase-shift of p between them. In conjunction with a non-iterative image reconstruction algorithm this permits the restoration of missing cone information. We show how fluorescence anisotropy could be used as a method to encode and decode the patterns simultaneously and develop a rigorous theoretical framework for the method. Through in-silico experiments and imaging of fixed biological cells on a structured illumination microscope that emulates the proposed setup we validate the feasibility of the method.
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Affiliation(s)
- Florian Ströhl
- Department of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS, Cambridge, UK.
- Department of Physics and Technology, UiT-The Arctic University of Norway, 9037, Tromsø, Norway.
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS, Cambridge, UK.
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25
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Conformational plasticity in the KcsA potassium channel pore helix revealed by homo-FRET studies. Sci Rep 2019; 9:6215. [PMID: 30996281 PMCID: PMC6470172 DOI: 10.1038/s41598-019-42405-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 03/29/2019] [Indexed: 11/24/2022] Open
Abstract
Potassium channels selectivity filter (SF) conformation is modulated by several factors, including ion-protein and protein-protein interactions. Here, we investigate the SF dynamics of a single Trp mutant of the potassium channel KcsA (W67) using polarized time-resolved fluorescence measurements. For the first time, an analytical framework is reported to analyze the homo-Förster resonance energy transfer (homo-FRET) within a symmetric tetrameric protein with a square geometry. We found that in the closed state (pH 7), the W67-W67 intersubunit distances become shorter as the average ion occupancy of the SF increases according to cation type and concentration. The hypothesis that the inactivated SF at pH 4 is structurally similar to its collapsed state, detected at low K+, pH 7, was ruled out, emphasizing the critical role played by the S2 binding site in the inactivation process of KcsA. This homo-FRET approach provides complementary information to X-ray crystallography in which the protein conformational dynamics is usually compromised.
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26
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Dlugosz P, Tresky R, Nimpf J. Differential Action of Reelin on Oligomerization of ApoER2 and VLDL Receptor in HEK293 Cells Assessed by Time-Resolved Anisotropy and Fluorescence Lifetime Imaging Microscopy. Front Mol Neurosci 2019; 12:53. [PMID: 30873003 PMCID: PMC6403468 DOI: 10.3389/fnmol.2019.00053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/12/2019] [Indexed: 01/12/2023] Open
Abstract
The canonical Reelin signaling cascade regulates correct neuronal layering during embryonic brain development. Details of this pathway are still not fully understood since the participating components are highly variable and create a complex mixture of interacting molecules. Reelin is proteolytically processed resulting in five different fragments some of which carrying the binding site for two different but highly homologous receptors, apolipoprotein E receptor 2 (ApoER2) and very low density lipoprotein receptor (VLDLR). The receptors are expressed in different variants in different areas of the developing brain. Binding of Reelin and its central fragment to the receptors results in phosphorylation of the intracellular adapter disabled-1 (Dab1) in neurons. Here, we studied the changes of the arrangement of the receptors upon Reelin binding and its central fragment at the molecular level in human embryonic kidney 293 (HEK293) cells by time-resolved anisotropy and fluorescence lifetime imaging microscopy (FLIM). In the off-state of the pathway ApoER2 and VLDLR form homo or hetero-di/oligomers. Upon binding of full length Reelin ApoER2 and VLDLR homo-oligomers are rearranged to higher order receptor clusters which leads to Dab1 phosphorylation. When the central fragment of Reelin binds to the receptors the cluster size of homo-oligomers is not affected and Dab1 is not phosphorylated. Hetero-oligomerization, however, can be induced, but does not lead to Dab1 phosphorylation. Cells expressing only ApoER2 or VLDLR change their shape when stimulated with the central fragment. Cells expressing ApoER2 produce filopodia/lamellipodia and cell size increases, whereas VLDLR-expressing cells decrease in size. These findings demonstrate that the primary event in the canonical Reelin pathway is the rearrangement of preformed receptor homo-oligomers to higher order clusters. In addition the possibility of yet another signaling mechanism which is mediated by the central Reelin fragment independent of Dab1 phosphorylation became apparent.
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Affiliation(s)
- Paula Dlugosz
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
| | - Roland Tresky
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
| | - Johannes Nimpf
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
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27
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Zhuang M, Perkins A, DeRosa CA, Butler T, Demas JN, Fraser CL. Meta
-Dimethoxy-Substituted Difluoroboron Dibenzoylmethane Poly(Lactic Acid) Nanoparticles for Luminescence Anisotropy. MACROMOL CHEM PHYS 2018. [DOI: 10.1002/macp.201800240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Meng Zhuang
- Department of Chemistry; University of Virginia; Charlottesville VA 22904 USA
| | - Anna Perkins
- Department of Chemistry; University of Virginia; Charlottesville VA 22904 USA
| | | | - Tristan Butler
- Department of Chemistry; University of Virginia; Charlottesville VA 22904 USA
| | - James N. Demas
- Department of Chemistry; University of Virginia; Charlottesville VA 22904 USA
| | - Cassandra L. Fraser
- Department of Chemistry; University of Virginia; Charlottesville VA 22904 USA
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28
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Masters TA, Marsh RJ, Blacker TS, Armoogum DA, Larijani B, Bain AJ. Polarized two-photon photoselection in EGFP: Theory and experiment. J Chem Phys 2018; 148:134311. [PMID: 29626864 DOI: 10.1063/1.5011642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this work, we present a complete theoretical description of the excited state order created by two-photon photoselection from an isotropic ground state; this encompasses both the conventionally measured quadrupolar (K = 2) and the "hidden" degree of hexadecapolar (K = 4) transition dipole alignment, their dependence on the two-photon transition tensor and emission transition dipole moment orientation. Linearly and circularly polarized two-photon absorption (TPA) and time-resolved single- and two-photon fluorescence anisotropy measurements are used to determine the structure of the transition tensor in the deprotonated form of enhanced green fluorescent protein. For excitation wavelengths between 800 nm and 900 nm, TPA is best described by a single element, almost completely diagonal, two-dimensional (planar) transition tensor whose principal axis is collinear to that of the single-photon S0 → S1 transition moment. These observations are in accordance with assignments of the near-infrared two-photon absorption band in fluorescent proteins to a vibronically enhanced S0 → S1 transition.
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Affiliation(s)
- T A Masters
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - R J Marsh
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - T S Blacker
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - D A Armoogum
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - B Larijani
- Cell Biophysics Laboratory, Ikerbasque, Basque Foundation for Science and Unidad de Biofisica (CSIC-UPV/EHU), Bilbao, Spain
| | - A J Bain
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
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29
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Wang L, Xue Y, Xing J, Song K, Lin J. Exploring the Spatiotemporal Organization of Membrane Proteins in Living Plant Cells. ANNUAL REVIEW OF PLANT BIOLOGY 2018; 69:525-551. [PMID: 29489393 DOI: 10.1146/annurev-arplant-042817-040233] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Plasma membrane proteins have important roles in transport and signal transduction. Deciphering the spatiotemporal organization of these proteins provides crucial information for elucidating the links between the behaviors of different molecules. However, monitoring membrane proteins without disrupting their membrane environment remains difficult. Over the past decade, many studies have developed single-molecule techniques, opening avenues for probing the stoichiometry and interactions of membrane proteins in their native environment by providing nanometer-scale spatial information and nanosecond-scale temporal information. In this review, we assess recent progress in the development of labeling and imaging technology for membrane protein analysis. We focus in particular on several single-molecule techniques for quantifying the dynamics and assembly of membrane proteins. Finally, we provide examples of how these new techniques are advancing our understanding of the complex biological functions of membrane proteins.
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Affiliation(s)
- Li Wang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China;
- Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Yiqun Xue
- Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jingjing Xing
- Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Kai Song
- Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jinxing Lin
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China;
- Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
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30
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de Las Heras-Martínez G, Andrieu J, Larijani B, Requejo-Isidro J. Quantifying intracellular equilibrium dissociation constants using single-channel time-resolved FRET. JOURNAL OF BIOPHOTONICS 2018; 11:e201600272. [PMID: 28485056 DOI: 10.1002/jbio.201600272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 06/07/2023]
Abstract
Quantification of the intracellular equilibrium dissociation constant of the interaction, Kd , is challenging due to the variability of the relative concentrations of the interacting proteins in the cell. Fluorescence lifetime imaging microscopy (FLIM) of the donor provides an accurate measurement of the molecular fraction of donor involved in FRET, but the fraction of bound acceptor is also needed to reliably estimate Kd . We present a method that exploits the spectroscopic properties of the widely used eGFP - mCherry FRET pair to rigorously determine the intracellular Kd based on imaging the fluorescence lifetime of only the donor (single-channel FLIM). We have assessed the effect of incomplete labelling and determined its range of application for different Kd using Monte Carlo simulations. We have demonstrated this method estimating the intracellular Kd for the homodimerisaton of the oncogenic protein 3-phosphoinositide-dependent kinase 1 (PDK1) in different cell lines and conditions, revealing a competitive mechanism for its regulation. The measured intracellular Kd was validated against in-vitro data. This method provides an accurate and generic tool to quantify protein interactions in situ.
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Affiliation(s)
| | - Josu Andrieu
- Instituto Biofisika (CSIC, UPV/EHU), Barrio de Sarriena s/n, 48940, Leioa, Spain
| | - Banafshé Larijani
- Instituto Biofisika (CSIC, UPV/EHU), Barrio de Sarriena s/n, 48940, Leioa, Spain
- Cell Biophysics Laboratory, Ikerbasque Basque Foundation for Science, Instituto Biofisika (CSIC, UPV/EHU) and Research Centre for Experimental Marine Biology and Biotechnology (PiE), University of the Basque Country (UPV/EHU), Leioa, 48940, Spain
| | - Jose Requejo-Isidro
- Instituto Biofisika (CSIC, UPV/EHU), Barrio de Sarriena s/n, 48940, Leioa, Spain
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31
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Ströhl F, Wong HHW, Holt CE, Kaminski CF. Total internal reflection fluorescence anisotropy imaging microscopy: setup, calibration, and data processing for protein polymerization measurements in living cells. Methods Appl Fluoresc 2017; 6:014004. [PMID: 28824013 PMCID: PMC5735343 DOI: 10.1088/2050-6120/aa872e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Fluorescence anisotropy imaging microscopy (FAIM) measures the depolarization properties of fluorophores to deduce molecular changes in their environment. For successful FAIM, several design principles have to be considered and a thorough system-specific calibration protocol is paramount. One important calibration parameter is the G factor, which describes the system-induced errors for different polarization states of light. The determination and calibration of the G factor is discussed in detail in this article. We present a novel measurement strategy, which is particularly suitable for FAIM with high numerical aperture objectives operating in TIRF illumination mode. The method makes use of evanescent fields that excite the sample with a polarization direction perpendicular to the image plane. Furthermore, we have developed an ImageJ/Fiji plugin, AniCalc, for FAIM data processing. We demonstrate the capabilities of our TIRF-FAIM system by measuring [Formula: see text]-actin polymerization in human embryonic kidney cells and in retinal neurons.
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Affiliation(s)
- Florian Ströhl
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, United Kingdom
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32
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van Rosmalen M, Krom M, Merkx M. Tuning the Flexibility of Glycine-Serine Linkers To Allow Rational Design of Multidomain Proteins. Biochemistry 2017; 56:6565-6574. [PMID: 29168376 PMCID: PMC6150656 DOI: 10.1021/acs.biochem.7b00902] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
![]()
Flexible
polypeptide linkers composed of glycine and serine are
important components of engineered multidomain proteins. We have previously
shown that the conformational properties of Gly-Gly-Ser repeat linkers
can be quantitatively understood by comparing experimentally determined
Förster resonance energy transfer (FRET) efficiencies of ECFP-linker-EYFP
proteins to theoretical FRET efficiencies calculated using wormlike
chain and Gaussian chain models. Here we extend this analysis to include
linkers with different glycine contents. We determined the FRET efficiencies
of ECFP-linker-EYFP proteins with linkers ranging in length from 25
to 73 amino acids and with glycine contents of 33.3% (GSSGSS), 16.7%
(GSSSSSS), and 0% (SSSSSSS). The FRET efficiency decreased with an
increasing linker length and was overall lower for linkers with less
glycine. Modeling the linkers using the WLC model revealed that the
experimentally observed FRET efficiencies were consistent with persistence
lengths of 4.5, 4.8, and 6.2 Å for the GSSGSS, GSSSSS, and SSSSSS
linkers, respectively. The observed increase in linker stiffness with
reduced glycine content is much less pronounced than that predicted
by a classical model developed by Flory and co-workers. We discuss
possible reasons for this discrepancy as well as implications for
using the stiffer linkers to control the effective concentrations
of connected domains in engineered multidomain proteins.
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Affiliation(s)
- Martijn van Rosmalen
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems (ICMS), Department of Biomedical Engineering, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Mike Krom
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems (ICMS), Department of Biomedical Engineering, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Maarten Merkx
- Laboratory of Chemical Biology and Institute for Complex Molecular Systems (ICMS), Department of Biomedical Engineering, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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33
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Mo GCH, Yip CM. Structural templating of J-aggregates: Visualizing bis(monoacylglycero)phosphate domains in live cells. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1687-1695. [PMID: 28844737 DOI: 10.1016/j.bbapap.2017.07.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/13/2017] [Accepted: 07/24/2017] [Indexed: 12/23/2022]
Abstract
Identifying the key structural and dynamical determinants that drive the association of biomolecules, whether in solution, or perhaps more importantly in a membrane environment, has critical implications for our understanding of cellular dynamics, processes, and signaling. With recent advances in high-resolution imaging techniques, from the development of new molecular labels to technical advances in imaging methodologies and platforms, researchers are now reaping the benefits of being able to directly characterize and quantify local dynamics, structures, and conformations in live cells and tissues. These capabilities are providing unique insights into association stoichiometries, interactions, and structures on sub-micron length scales. We previously examined the role of lipid headgroup chemistry and phase state in guiding the formation of pseudoisocyanine (PIC) dye J-aggregates on supported planar bilayers [Langmuir, 25, 10719]. We describe here how these same J-aggregates can report on the in situ formation of organellar membrane domains in live cells. Live cell hyperspectral confocal microscopy using GFP-conjugated GTPase markers of early (Rab5) and late (Rab7) endosomes revealed that the PIC J-aggregates were confined to domains on either the limiting membrane or intralumenal vesicles (ILV) of late endosomes, known to be enriched in the anionic lipid bis(monoacylglycero)phosphate (BMP). Correlated confocal fluorescence - atomic force microscopy performed on endosomal membrane-mimetic supported planar lipid bilayers confirmed BMP-specific templating of the PIC J-aggregates. These data provide strong evidence for the formation of BMP-rich lipid domains during multivesicular body formation and portend the application of structured dye aggregates as markers of cellular membrane domain structure, size, and formation.
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Affiliation(s)
- Gary C H Mo
- Department of Chemical Engineering and Applied Chemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada; Department of Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
| | - Christopher M Yip
- Department of Biochemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada; Department of Chemical Engineering and Applied Chemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada; Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada.
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34
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Akamatsu K, Shikazono N, Saito T. New method for estimating clustering of DNA lesions induced by physical/chemical mutagens using fluorescence anisotropy. Anal Biochem 2017; 536:78-89. [PMID: 28827125 DOI: 10.1016/j.ab.2017.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/02/2017] [Accepted: 08/11/2017] [Indexed: 12/31/2022]
Abstract
We have developed a new method for estimating the localization of DNA damage such as apurinic/apyrimidinic sites (APs) on DNA using fluorescence anisotropy. This method is aimed at characterizing clustered DNA damage produced by DNA-damaging agents such as ionizing radiation and genotoxic chemicals. A fluorescent probe with an aminooxy group (AlexaFluor488) was used to label APs. We prepared a pUC19 plasmid with APs by heating under acidic conditions as a model for damaged DNA, and subsequently labeled the APs. We found that the observed fluorescence anisotropy (robs) decreases as averaged AP density (λAP: number of APs per base pair) increases due to homo-FRET, and that the APs were randomly distributed. We applied this method to three DNA-damaging agents, 60Co γ-rays, methyl methanesulfonate (MMS), and neocarzinostatin (NCS). We found that robs-λAP relationships differed significantly between MMS and NCS. At low AP density (λAP < 0.001), the APs induced by MMS seemed to not be closely distributed, whereas those induced by NCS were remarkably clustered. In contrast, the AP clustering induced by 60Co γ-rays was similar to, but potentially more likely to occur than, random distribution. This simple method can be used to estimate mutagenicity of ionizing radiation and genotoxic chemicals.
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Affiliation(s)
- Ken Akamatsu
- Radiation DNA Damage Research Group, Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology (QST), 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan.
| | - Naoya Shikazono
- Radiation DNA Damage Research Group, Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology (QST), 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan
| | - Takeshi Saito
- Radiation Biochemistry and Biological Function, Research Reactor Institute, Kyoto University, Kumatori, Sennan, Osaka 590-0494, Japan
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35
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Vinegoni C, Fumene Feruglio P, Brand C, Lee S, Nibbs AE, Stapleton S, Shah S, Gryczynski I, Reiner T, Mazitschek R, Weissleder R. Measurement of drug-target engagement in live cells by two-photon fluorescence anisotropy imaging. Nat Protoc 2017; 12:1472-1497. [PMID: 28686582 PMCID: PMC5928516 DOI: 10.1038/nprot.2017.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability to directly image and quantify drug-target engagement and drug distribution with subcellular resolution in live cells and whole organisms is a prerequisite to establishing accurate models of the kinetics and dynamics of drug action. Such methods would thus have far-reaching applications in drug development and molecular pharmacology. We recently presented one such technique based on fluorescence anisotropy, a spectroscopic method based on polarization light analysis and capable of measuring the binding interaction between molecules. Our technique allows the direct characterization of target engagement of fluorescently labeled drugs, using fluorophores with a fluorescence lifetime larger than the rotational correlation of the bound complex. Here we describe an optimized protocol for simultaneous dual-channel two-photon fluorescence anisotropy microscopy acquisition to perform drug-target measurements. We also provide the necessary software to implement stream processing to visualize images and to calculate quantitative parameters. The assembly and characterization part of the protocol can be implemented in 1 d. Sample preparation, characterization and imaging of drug binding can be completed in 2 d. Although currently adapted to an Olympus FV1000MPE microscope, the protocol can be extended to other commercial or custom-built microscopes.
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Affiliation(s)
- Claudio Vinegoni
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Paolo Fumene Feruglio
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Department of Neurosciences, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy
| | - Christian Brand
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Sungon Lee
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- School of Electrical Engineering, Hanyang University, Ansan, Republic of Korea
| | - Antoinette E Nibbs
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Shawn Stapleton
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Sunil Shah
- Institute for Molecular Medicine, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Ignacy Gryczynski
- Institute for Molecular Medicine, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Thomas Reiner
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Ralph Mazitschek
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Ralph Weissleder
- Center for System Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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36
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Luby BM, Charron DM, MacLaughlin CM, Zheng G. Activatable fluorescence: From small molecule to nanoparticle. Adv Drug Deliv Rev 2017; 113:97-121. [PMID: 27593264 DOI: 10.1016/j.addr.2016.08.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/15/2016] [Accepted: 08/27/2016] [Indexed: 12/23/2022]
Abstract
Molecular imaging has emerged as an indispensable technology in the development and application of drug delivery systems. Targeted imaging agents report the presence of biomolecules, including therapeutic targets and disease biomarkers, while the biological behaviour of labelled delivery systems can be non-invasively assessed in real time. As an imaging modality, fluorescence offers additional signal specificity and dynamic information due to the inherent responsivity of fluorescence agents to interactions with other optical species and with their environment. Harnessing this responsivity is the basis of activatable fluorescence imaging, where interactions between an engineered fluorescence agent and its biological target induce a fluorogenic response. Small molecule activatable agents are frequently derivatives of common fluorophores designed to chemically react with their target. Macromolecular scale agents are useful for imaging proteins and nucleic acids, although their biological delivery can be difficult. Nanoscale activatable agents combine the responsivity of fluorophores with the unique optical and physical properties of nanomaterials. The molecular imaging application and overall complexity of biological target dictate the most advantageous fluorescence agent size scale and activation strategy.
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Affiliation(s)
- Benjamin M Luby
- Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada
| | - Danielle M Charron
- Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Christina M MacLaughlin
- Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada
| | - Gang Zheng
- Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
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37
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Gielen F, Butz M, Rees EJ, Erdelyi M, Moschetti T, Hyvönen M, Edel JB, Kaminski CF, Hollfelder F. Quantitative Affinity Determination by Fluorescence Anisotropy Measurements of Individual Nanoliter Droplets. Anal Chem 2017; 89:1092-1101. [PMID: 28192993 PMCID: PMC5287478 DOI: 10.1021/acs.analchem.6b02528] [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] [Indexed: 01/23/2023]
Abstract
Fluorescence anisotropy measurements of reagents compartmentalized into individual nanoliter droplets are shown to yield high-resolution binding curves from which precise dissociation constants (Kd) for protein-peptide interactions can be inferred. With the current platform, four titrations can be obtained per minute (based on ∼100 data points each), with stoichiometries spanning more than 2 orders of magnitude and requiring only tens of microliters of reagents. In addition to affinity measurements with purified components, Kd values for unpurified proteins in crude cell lysates can be obtained without prior knowledge of the concentration of the expressed protein, so that protein purification can be avoided. Finally, we show how a competition assay can be set up to perform focused library screens, so that compound labeling is not required anymore. These data demonstrate the utility of droplet compartments for the quantitative characterization of biomolecular interactions and establish fluorescence anisotropy imaging as a quantitative technique in a miniaturized droplet format, which is shown to be as reliable as its macroscopic test tube equivalent.
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Affiliation(s)
- Fabrice Gielen
- Department of Biochemistry, University of Cambridge , 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom.,Living Systems Institute, University of Exeter , Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Maren Butz
- Department of Biochemistry, University of Cambridge , 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Eric J Rees
- Department of Chemical Engineering and Biotechnology, New Museums Site , Pembroke Street, Cambridge, CB2 3RA, United Kingdom
| | - Miklos Erdelyi
- Department of Chemical Engineering and Biotechnology, New Museums Site , Pembroke Street, Cambridge, CB2 3RA, United Kingdom.,Department of Optics and Quantum Electronics, University of Szeged , Dom ter 9, Szeged, Hungary
| | - Tommaso Moschetti
- Department of Biochemistry, University of Cambridge , 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Marko Hyvönen
- Department of Biochemistry, University of Cambridge , 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Joshua B Edel
- Department of Chemistry, Imperial College London , South Kensington, London, SW7 2AZ, United Kingdom
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, New Museums Site , Pembroke Street, Cambridge, CB2 3RA, United Kingdom
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge , 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
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38
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Slyngborg M, Nielsen DA, Fojan P. The Physical Properties and Self-Assembly Potential of the RFFFR Peptide. Chembiochem 2016; 17:2083-2092. [PMID: 27581944 DOI: 10.1002/cbic.201600383] [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: 07/07/2016] [Indexed: 12/22/2022]
Abstract
The self-assembly of fibers from peptides has attracted a tremendous amount of attention due to its many applications, such as in drug-delivery systems, in tissue engineering, and in electronic devices. Recently, the self-assembly potential of the designer peptide RFFFR has been reported. Here it is experimentally verified that the peptide forms fibers that are entangled and form solid spheres without water inside. Upon dilution below the critical fiber concentration, the fibers untangle and become totally separated prior to dissolution. These structures readily bind thioflavin T, resulting in a characteristic change in fluorescent properties consistent with β-sheet-rich amyloid structures with aromatic/hydrophobic grooves. The circular dichroism spectroscopy data are dominated by a π→π* transition, thus indicating that the fibers are stabilized by π-stacking. Contrary to what was expected, the dissolution of the spheres/fibers results in increasing fluorescence anisotropy over time. This is explained in terms of HomoFRET between phenylalanine residues with a T-shaped π-stacking mode, which was determined in another study to be the dominant mode through atomistic simulations and semiempirical calculations. Kelvin probe force microscopy measurements indicate that the spheres and fibers have a conductivity comparable to that of gold. Hence, these self-assembled structures might be applicable in organic solid-state electronic devices. The dissolution properties of the spheres further suggest that they might be used as drug-delivery systems.
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Affiliation(s)
- Morten Slyngborg
- Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4 A, 9220, Aalborg Øst, Denmark
| | - Dennis Achton Nielsen
- Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4 A, 9220, Aalborg Øst, Denmark
| | - Peter Fojan
- Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4 A, 9220, Aalborg Øst, Denmark.
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Kaminski CF, Kaminski Schierle GS. Probing amyloid protein aggregation with optical superresolution methods: from the test tube to models of disease. NEUROPHOTONICS 2016; 3:041807. [PMID: 27413767 PMCID: PMC4925874 DOI: 10.1117/1.nph.3.4.041807] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/13/2016] [Indexed: 05/02/2023]
Abstract
The misfolding and self-assembly of intrinsically disordered proteins into insoluble amyloid structures are central to many neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Optical imaging of this self-assembly process in vitro and in cells is revolutionizing our understanding of the molecular mechanisms behind these devastating conditions. In contrast to conventional biophysical methods, optical imaging and, in particular, optical superresolution imaging, permits the dynamic investigation of the molecular self-assembly process in vitro and in cells, at molecular-level resolution. In this article, current state-of-the-art imaging methods are reviewed and discussed in the context of research into neurodegeneration.
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Affiliation(s)
- Clemens F. Kaminski
- University of Cambridge, Department of Chemical Engineering and Biotechnology, Pembroke Street, Cambridge CB2 3RA, United Kingdom
- Address all correspondence to: Clemens F. Kaminski, E-mail:
| | - Gabriele S. Kaminski Schierle
- University of Cambridge, Department of Chemical Engineering and Biotechnology, Pembroke Street, Cambridge CB2 3RA, United Kingdom
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40
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Laine RF, Kaminski Schierle GS, van de Linde S, Kaminski CF. From single-molecule spectroscopy to super-resolution imaging of the neuron: a review. Methods Appl Fluoresc 2016; 4:022004. [PMID: 28809165 PMCID: PMC5390958 DOI: 10.1088/2050-6120/4/2/022004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/09/2016] [Accepted: 05/19/2016] [Indexed: 12/03/2022]
Abstract
For more than 20 years, single-molecule spectroscopy has been providing invaluable insights into nature at the molecular level. The field has received a powerful boost with the development of the technique into super-resolution imaging methods, ca. 10 years ago, which overcome the limitations imposed by optical diffraction. Today, single molecule super-resolution imaging is routinely used in the study of macromolecular function and structure in the cell. Concomitantly, computational methods have been developed that provide information on numbers and positions of molecules at the nanometer-scale. In this overview, we outline the technical developments that have led to the emergence of localization microscopy techniques from single-molecule spectroscopy. We then provide a comprehensive review on the application of the technique in the field of neuroscience research.
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Affiliation(s)
- Romain F Laine
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, Cambridge University, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Gabriele S Kaminski Schierle
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, Cambridge University, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Sebastian van de Linde
- Department of Biotechnology and Biophysics, Julius-Maximilians-University, Am Hubland, D-97074 Würzburg, Germany
| | - Clemens F Kaminski
- Laser Analytics Group, Department of Chemical Engineering and Biotechnology, Cambridge University, Pembroke Street, Cambridge, CB2 3RA, UK
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Apollo-NADP(+): a spectrally tunable family of genetically encoded sensors for NADP(+). Nat Methods 2016; 13:352-8. [PMID: 26878383 DOI: 10.1038/nmeth.3764] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 01/08/2016] [Indexed: 02/03/2023]
Abstract
NADPH-dependent antioxidant pathways have a critical role in scavenging hydrogen peroxide (H2O2) produced by oxidative phosphorylation. Inadequate scavenging results in H2O2 accumulation and can cause disease. To measure NADPH/NADP(+) redox states, we explored genetically encoded sensors based on steady-state fluorescence anisotropy due to FRET (fluorescence resonance energy transfer) between homologous fluorescent proteins (homoFRET); we refer to these sensors as Apollo sensors. We created an Apollo sensor for NADP(+) (Apollo-NADP(+)) that exploits NADP(+)-dependent homodimerization of enzymatically inactive glucose-6-phosphate dehydrogenase (G6PD). This sensor is reversible, responsive to glucose-stimulated metabolism and spectrally tunable for compatibility with many other sensors. We used Apollo-NADP(+) to study beta cells responding to oxidative stress and demonstrated that NADPH is significantly depleted before H2O2 accumulation by imaging a Cerulean-tagged version of Apollo-NADP(+) with the H2O2 sensor HyPer.
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42
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Sahasrabudhe A, Ghate K, Mutalik S, Jacob A, Ghose A. Formin 2 regulates the stabilization of filopodial tip adhesions in growth cones and affects neuronal outgrowth and pathfinding in vivo. Development 2015; 143:449-60. [PMID: 26718007 DOI: 10.1242/dev.130104] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/23/2015] [Indexed: 12/28/2022]
Abstract
Growth cone filopodia are actin-based mechanosensory structures that are essential for chemoreception and the generation of contractile forces necessary for directional motility. However, little is known about the influence of filopodial actin structures on substrate adhesion and filopodial contractility. Formin 2 (Fmn2) localizes along filopodial actin bundles and its depletion does not affect filopodia initiation or elongation. However, Fmn2 activity is required for filopodial tip adhesion maturation and the ability of filopodia to generate traction forces. Dysregulation of filopodia in Fmn2-depleted neurons leads to compromised growth cone motility. Additionally, in mouse fibroblasts, Fmn2 regulates ventral stress fiber assembly and affects the stability of focal adhesions. In the developing chick spinal cord, Fmn2 activity is required cell-autonomously for the outgrowth and pathfinding of spinal commissural neurons. Our results reveal an unanticipated function for Fmn2 in neural development. Fmn2 regulates structurally diverse bundled actin structures, parallel filopodial bundles in growth cones and anti-parallel stress fibers in fibroblasts, in turn modulating the stability of substrate adhesions. We propose Fmn2 as a mediator of actin bundle integrity, enabling efficient force transmission to the adhesion sites.
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Affiliation(s)
- Abhishek Sahasrabudhe
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Ketakee Ghate
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Sampada Mutalik
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Ajesh Jacob
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
| | - Aurnab Ghose
- Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhaba Road, Pune 411008, India
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Yi NY, He Q, Caligan TB, Smith GR, Forsberg LJ, Brenman JE, Sexton JZ. Development of a Cell-Based Fluorescence Polarization Biosensor Using Preproinsulin to Identify Compounds That Alter Insulin Granule Dynamics. Assay Drug Dev Technol 2015; 13:558-69. [PMID: 26505612 PMCID: PMC4955689 DOI: 10.1089/adt.2015.665] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Diabetes currently affects 9.3% of the U.S. population totaling $245 billion annually in U.S. direct and indirect healthcare costs. Current therapies for diabetes are limited in their ability to control blood glucose and/or enhance insulin sensitivity. Therefore, innovative and efficacious therapies for diabetes are urgently needed. Herein we describe a fluorescent insulin reporter system (preproinsulin-mCherry, PPI-mCherry) that tracks live-cell insulin dynamics and secretion in pancreatic β-cells with utility for high-content assessment of real-time insulin dynamics. Additionally, we report a new modality for sensing insulin granule packaging in conventional high-throughput screening (HTS), using a hybrid cell-based fluorescence polarization (FP)/internal FRET biosensor using the PPI-mCherry reporter system. We observed that bafilomycin, a vacuolar H(+) ATPase inhibitor and inhibitor of insulin granule formation, significantly increased mCherry FP in INS-1 cells with PPI-mCherry. Partial least squares regression analysis demonstrated that an increase of FP by bafilomycin is significantly correlated with a decrease in granularity of PPI-mCherry signal in the cells. The increased FP by bafilomycin is due to inhibition of self-Förster resonant energy transfer (homo-FRET) caused by the increased mCherry intermolecular distance. FP substantially decreases when insulin is tightly packaged in the granules, and the homo-FRET decreases when insulin granule packaging is inhibited, resulting in increased FP. We performed pilot HTS of 1782 FDA-approved small molecules and natural products from Prestwick and Enzo chemical libraries resulting in an overall Z'-factor of 0.52 ± 0.03, indicating the suitability of this biosensor for HTS. This novel biosensor enables live-cell assessment of protein-protein interaction/protein aggregation in live cells and is compatible with conventional FP plate readers.
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Affiliation(s)
- Na Young Yi
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Qingping He
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Thomas B. Caligan
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Ginger R. Smith
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Lawrence J. Forsberg
- The Neuroscience Center and Department of Cell Biology & Physiology, UNC Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Jay E. Brenman
- The Neuroscience Center and Department of Cell Biology & Physiology, UNC Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Jonathan Z. Sexton
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
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Nåbo LJ, List NH, Witzke S, Wüstner D, Khandelia H, Kongsted J. Design of new fluorescent cholesterol and ergosterol analogs: Insights from theory. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2188-99. [DOI: 10.1016/j.bbamem.2015.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/24/2015] [Accepted: 04/29/2015] [Indexed: 12/23/2022]
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Melo AM, Fedorov A, Prieto M, Coutinho A. Exploring homo-FRET to quantify the oligomer stoichiometry of membrane-bound proteins involved in a cooperative partition equilibrium. Phys Chem Chem Phys 2015; 16:18105-17. [PMID: 24722583 DOI: 10.1039/c4cp00060a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The establishment of protein-protein interactions between membrane-bound proteins is associated with several biological functions and dysfunctions. Here, an analytical framework that uses energy homo transfer to directly probe quantitatively the oligomerization state of membrane-bound proteins engaged in a three-state cooperative partition is presented. Briefly, this model assumes that monomeric protein molecules partition into the bilayer surface and reversibly assemble into oligomers with k subunits. A general equation relating the overall steady-state fluorescence anisotropy of the sample to its fractional labeling was derived by considering explicitly that the anisotropy of mixed oligomers containing i-labeled monomers is inversely proportional to the number of labeled subunits per oligomer (Runnels and Scarlata limit). This method was very robust in describing the electrostatic interaction of Alexa Fluor 488 fluorescently labeled lysozyme (Lz-A488) with phosphatidylserine-containing membranes. The pronounced decrease detected in the fluorescence anisotropy of Lz-A488 always correlated with the system reaching a high membrane surface density of the protein (at a low lipid-to-protein (L/P) molar ratio). The occurrence of energy homo transfer-induced fluorescence depolarization was further confirmed by measuring the anisotropy decays of Lz-A488 under these conditions. A global analysis of the steady-state anisotropy data obtained under a wide range of experimental conditions (variable anionic lipid content of the liposomes, L/P molar ratios and protein fractional labeling) confirmed that membrane-bound Lz-A488 assembled into oligomeric complexes, possibly with a stoichiometry of k = 6 ± 1. This study illustrates that even in the presence of a coupled partition-oligomerization equilibrium, steady-state anisotropy measurements provide a simple and reliable tool to monitor the self-assembly of membrane-bound proteins.
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Affiliation(s)
- Ana M Melo
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
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47
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Davies T, Kodera N, Kaminski Schierle GS, Rees E, Erdelyi M, Kaminski CF, Ando T, Mishima M. CYK4 promotes antiparallel microtubule bundling by optimizing MKLP1 neck conformation. PLoS Biol 2015; 13:e1002121. [PMID: 25875822 PMCID: PMC4395295 DOI: 10.1371/journal.pbio.1002121] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 03/05/2015] [Indexed: 11/19/2022] Open
Abstract
Centralspindlin, a constitutive 2:2 heterotetramer of MKLP1 (a kinesin-6) and the non-motor subunit CYK4, plays important roles in cytokinesis. It is crucial for the formation of central spindle microtubule bundle structure. Its accumulation at the central antiparallel overlap zone is key for recruitment and regulation of downstream cytokinesis factors and for stable anchoring of the plasma membrane at the midbody. Both MKLP1 and CYK4 are required for efficient microtubule bundling. However, the mechanism by which CYK4 contributes to this is unclear. Here we performed structural and functional analyses of centralspindlin using high-speed atomic force microscopy, Fӧrster resonance energy transfer analysis, and in vitro reconstitution. Our data reveal that CYK4 binds to a globular mass in the atypically long MKLP1 neck domain between the catalytic core and the coiled coil and thereby reconfigures the two motor domains in the MKLP1 dimer to be suitable for antiparallel microtubule bundling. Our work provides insights into the microtubule bundling during cytokinesis and into the working mechanisms of the kinesins with non-canonical neck structures. Cell division depends on the antiparallel bundling of microtubules by a motor complex called centralpindlin. This study reveals how the centralspindlin non-motor subunit CYK4 reconfigures the motor domains of the kinesin subunit MKLP1 to help it carry out this role. Cell division requires coordination of many different cellular components. Cytokinesis is the process by which the cytoplasm divides between the two forming daughter cells. During cytokinesis, centralspindlin is truly central, as it organizes microtubule bundle structures, recruits other factors to the site of division, and anchors the plasma membrane at the inter-cellular bridge while the two daughter cells are waiting for the final separation. Centralspindlin is a heterotetramer composed of two molecules of a kinesin-6 motor subunit, MKLP1, and two molecules of the second subunit, CYK4. For efficient microtubule bundling, both the microtubule motor subunit MKLP1 and the non-motor CYK4 subunit are required. However, it has remained unclear how CYK4 contributes to this activity. Here, we took a combinatorial approach to investigate this process, using in vitro reconstitution and structural analyses by atomic force microscopy and Förster resonance energy transfer. We revealed that the CYK4 dimer binds to a hitherto unknown globular domain at the neck of the MKLP1 dimer and optimizes the configuration of two motor domains, making them suitable for antiparallel microtubule bundling. This provides novel insight into how other kinesin superfamily molecules with non-canonical neck structures may work.
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Affiliation(s)
- Tim Davies
- Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom
| | - Noriyuki Kodera
- Department of Physics and Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa, Japan
| | - Gabriele S. Kaminski Schierle
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge, United Kingdom
| | - Eric Rees
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge, United Kingdom
| | - Miklos Erdelyi
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge, United Kingdom
| | - Clemens F. Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge, United Kingdom
| | - Toshio Ando
- Department of Physics and Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa, Japan
| | - Masanori Mishima
- Biomedical Cell Biology, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, United Kingdom
- * E-mail:
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Shrestha D, Jenei A, Nagy P, Vereb G, Szöllősi J. Understanding FRET as a research tool for cellular studies. Int J Mol Sci 2015; 16:6718-56. [PMID: 25815593 PMCID: PMC4424985 DOI: 10.3390/ijms16046718] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/18/2015] [Indexed: 01/06/2023] Open
Abstract
Communication of molecular species through dynamic association and/or dissociation at various cellular sites governs biological functions. Understanding these physiological processes require delineation of molecular events occurring at the level of individual complexes in a living cell. Among the few non-invasive approaches with nanometer resolution are methods based on Förster Resonance Energy Transfer (FRET). FRET is effective at a distance of 1-10 nm which is equivalent to the size of macromolecules, thus providing an unprecedented level of detail on molecular interactions. The emergence of fluorescent proteins and SNAP- and CLIP- tag proteins provided FRET with the capability to monitor changes in a molecular complex in real-time making it possible to establish the functional significance of the studied molecules in a native environment. Now, FRET is widely used in biological sciences, including the field of proteomics, signal transduction, diagnostics and drug development to address questions almost unimaginable with biochemical methods and conventional microscopies. However, the underlying physics of FRET often scares biologists. Therefore, in this review, our goal is to introduce FRET to non-physicists in a lucid manner. We will also discuss our contributions to various FRET methodologies based on microscopy and flow cytometry, while describing its application for determining the molecular heterogeneity of the plasma membrane in various cell types.
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Affiliation(s)
- Dilip Shrestha
- Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Nagyerdei Krt. 98, Debrecen 4032, Hungary.
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary.
| | - Attila Jenei
- Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Nagyerdei Krt. 98, Debrecen 4032, Hungary.
| | - Péter Nagy
- Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Nagyerdei Krt. 98, Debrecen 4032, Hungary.
| | - György Vereb
- Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Nagyerdei Krt. 98, Debrecen 4032, Hungary.
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary.
| | - János Szöllősi
- Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Nagyerdei Krt. 98, Debrecen 4032, Hungary.
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Egyetem tér 1, Debrecen 4032, Hungary.
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Affiliation(s)
- Manuel M. Müller
- Department of Chemistry, Princeton University,
Frick Laboratory, Princeton, New Jersey 08544, United States
| | - Tom W. Muir
- Department of Chemistry, Princeton University,
Frick Laboratory, Princeton, New Jersey 08544, United States
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50
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Wazawa T, Morimoto N, Nagai T, Suzuki M. Rotational motion of rhodamine 6G tethered to actin through oligo(ethylene glycol) linkers studied by frequency-domain fluorescence anisotropy. Biophys Physicobiol 2015; 12:87-102. [PMID: 27493858 PMCID: PMC4736842 DOI: 10.2142/biophysico.12.0_87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 11/02/2015] [Indexed: 12/01/2022] Open
Abstract
Investigation of the rotational motion of a fluorescent probe tethered to a protein helps to elucidate the local properties of the solvent and protein near the conjugation site of the probe. In this study, we have developed an instrument for frequency-domain fluorescence (FDF) anisotropy measurements, and studied how the local properties around a protein, actin, can be elucidated from the rotational motion of a dye tethered to actin. Rhodamine 6G (R6G) was attached to Cys-374 using newly-synthesized R6G-maleimide with three different oligo(ethylene glycol) (OEG) linker lengths. The time-resolved anisotropy decay of R6G tethered to G-actin was revealed to be a combination of the two modes of the wobbling motion of R6G and the tumbling motion of G-actin. The rotational diffusion coefficient (RDC) of R6G wobbling was ~0.1 ns−1 at 20°C and increased with OEG linker length. The use of the three R6G-actin conjugates of different linker lengths was useful to not only figure out the linker length dependence of the rotational motion of R6G but also validate the analyses. In the presence of a cosolvent of glycerol, although the tumbling motion of G-actin was retarded in response to the bulk viscosity, the wobbling motion of R6G tethered to actin exhibited an increase of RDC as glycerol concentration increased. This finding suggests an intricate relationship between the fluid properties of the bulk solvent and the local environment around actin.
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Affiliation(s)
- Tetsuichi Wazawa
- Department of Biomolecular Science and Engineering, Institute for Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan; Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Nobuyuki Morimoto
- Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Takeharu Nagai
- Department of Biomolecular Science and Engineering, Institute for Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Makoto Suzuki
- Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
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