1
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Bacalum M, Radu M, Osella S, Knippenberg S, Ameloot M. Generalized polarization and time-resolved fluorescence provide evidence for different populations of Laurdan in lipid vesicles. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 250:112833. [PMID: 38141326 DOI: 10.1016/j.jphotobiol.2023.112833] [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: 10/09/2023] [Revised: 11/29/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
The solvatochromic dye Laurdan is widely used in sensing the lipid packing of both model and biological membranes. The fluorescence emission maximum shifts from about 440 nm (blue channel) in condensed membranes (So) to about 490 nm (green channel) in the liquid-crystalline phase (Lα). Although the fluorescence intensity based generalized polarization (GP) is widely used to characterize lipid membranes, the fluorescence lifetime of Laurdan, in the blue and the green channel, is less used for that purpose. Here we explore the correlation between GP and fluorescence lifetimes by spectroscopic measurements on the So and Lα phases of large unilamellar vesicles of DMPC and DPPC. A positive correlation between GP and the lifetimes is observed in each of the optical channels for the two lipid phases. Microfluorimetric determinations on giant unilamellar vesicles of DPPC and DOPC at room temperature are performed under linearly polarized two-photon excitation to disentangle possible subpopulations of Laurdan at a scale below the optical resolution. Fluorescence intensities, GP and fluorescence lifetimes depend on the angle between the orientation of the linear polarization of the excitation light and the local normal to the membrane of the optical cross-section. This angular variation depends on the lipid phase and the emission channel. GP and fluorescence intensities in the blue and green channel in So and in the blue channel in Lα exhibit a minimum near 90o. Surprisingly, the intensity in the green channel in Lα reaches a maximum near 90o. The fluorescence lifetimes in the two optical channels also reach a pronounced minimum near 90o in So and Lα, apart from the lifetime in the blue channel in Lα where the lifetime is short with minimal angular variation. To our knowledge, these experimental observations are the first to demonstrate the existence of a bent conformation of Laurdan in lipid membranes, as previously suggested by molecular dynamics calculations.
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Affiliation(s)
- Mihaela Bacalum
- Department of Life and Environmental Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, Reactorului, 30, Măgurele 077125, Romania
| | - Mihai Radu
- Department of Life and Environmental Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, Reactorului, 30, Măgurele 077125, Romania
| | - Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Stefan Knippenberg
- Biomedical Research Institute, Hasselt University, Agoralaan Bldg. C, 3590 Diepenbeek, Belgium; Theory Lab, Hasselt University, Agoralaan Bldg. D, 3590 Diepenbeek, Belgium
| | - Marcel Ameloot
- Biomedical Research Institute, Hasselt University, Agoralaan Bldg. C, 3590 Diepenbeek, Belgium.
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2
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Schnupfhagn C, Schumacher T, Markus P, Papastavrou G, Aftenieva O, König TAF, Dudko V, Matejdes M, Breu J, Lippitz M. Disentangling the Orientations of Spectrally Overlapping Transition Dipoles in Dense Dye Layers. NANO LETTERS 2022; 22:7499-7505. [PMID: 36094390 DOI: 10.1021/acs.nanolett.2c02438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The transition dipole orientations of dye assemblies in heterostructures have a crucial impact on the efficiency of novel optoelectronic devices such as organic thin-film transistors and light-emitting diodes. These devices are frequently based on heterojunctions and tandem structures featuring multiple optical transitions. Precise knowledge of preferred orientations, spatial order, and spatial variations is highly relevant. We present a fast and universal large-area screening method to determine the transition dipole orientations in dye assemblies with diffraction-limited spatial resolution. Moreover, our hyperspectral imaging approach disentangles the orientations of different chromophores. As a demonstration, we apply our technique to dye monolayers with two optical transitions sandwiched between two ultrathin silicate nanosheets. A comprehensive model for dipole orientation distributions in monolayers reveals a long-range orientational order and a strong correlation between the two transitions.
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Affiliation(s)
| | | | - Paul Markus
- Physical Chemistry II, University of Bayreuth, Bayreuth 95447, Germany
| | - Georg Papastavrou
- Physical Chemistry II, University of Bayreuth, Bayreuth 95447, Germany
| | - Olha Aftenieva
- Institute of Physical Chemistry and Polymer Physics, Leibniz-Institut für Polymerforschung Dresden e.V., Dresden 01069, Germany
- Center for Advancing Electronics Dresden (CFAED), Technische Universität Dresden, Helmholtzstraße 18, Dresden 01069, Germany
| | - Tobias A F König
- Institute of Physical Chemistry and Polymer Physics, Leibniz-Institut für Polymerforschung Dresden e.V., Dresden 01069, Germany
- Center for Advancing Electronics Dresden (CFAED), Technische Universität Dresden, Helmholtzstraße 18, Dresden 01069, Germany
| | - Volodymyr Dudko
- Inorganic Chemistry I, University of Bayreuth, Bayreuth 95447, Germany
| | - Marian Matejdes
- Inorganic Chemistry I, University of Bayreuth, Bayreuth 95447, Germany
| | - Josef Breu
- Inorganic Chemistry I, University of Bayreuth, Bayreuth 95447, Germany
| | - Markus Lippitz
- Experimental Physics III, University of Bayreuth, Bayreuth 95447, Germany
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3
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Chatterjee A, Sharma AK, Purkayastha P. Development of a carbon dot and methylene blue NIR-emitting FLIM-FRET pair in niosomes for controlled ROS generation. NANOSCALE 2022; 14:6570-6584. [PMID: 35420619 DOI: 10.1039/d2nr01032a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Non-ionic surfactant vesicular systems (niosomes) are structurally similar to lipid vesicles, differing only in the bilayer composition. Herein we report a unique method to generate reactive oxygen species (ROS) utilizing a FLIM-FRET technique involving niosome-trapped yellow emissive carbon dots (YCDs) and methylene blue (MB) in aqueous medium under neutral conditions. Niosomes are biologically important because of their good stability and extremely low toxicity. Fluorescent CDs, emitting in the higher wavelengths on visible light excitation, are of incredible importance in bio-imaging and optoelectronics. Hence, we prepared nitrogen-containing YCDs from a single precursor, o-phenylenediamine, and explained their detailed photophysics upon incorporation into the niosomal bilayer. The YCDs are polarity sensitive, and are rotationally restricted in niosomes, which increases their fluorescence quantum yield from 29% (in water) to 91%. These YCDs are tactically employed to develop a near infrared (NIR) FRET pair with methylene blue (MB), which is a very well-known type-I and type-II photosensitizer. This FRET pair, which emits in the NIR region, is found to be an ideal system to generate ROS by excitation in the lower visible wavelengths. Interestingly, the ROS production by MB from the dissolved oxygen is enhanced inside the niosomes. The donor and the acceptor moieties in this unique NIR-emitting FRET pair display an unprecedented 300 nm Stokes shift. The findings could be influential in bio-imaging in the NIR region evading cellular autofluorescence and the controllably generated ROS can be further applied as a potential photodynamic therapeutic agent.
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Affiliation(s)
- Arunavo Chatterjee
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, WB, India.
| | - Ankit Kumar Sharma
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, WB, India.
| | - Pradipta Purkayastha
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, WB, India.
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4
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Gasecka P, Balla NK, Sison M, Brasselet S. Lipids-Fluorophores Interactions Probed by Combined Nonlinear Polarized Microscopy. J Phys Chem B 2021; 125:13718-13729. [PMID: 34902969 DOI: 10.1021/acs.jpcb.1c07866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studying the structural dynamics of lipid membranes requires methods that can address both microscopic and macroscopic characteristics. Fluorescence imaging is part of the most used techniques to study membrane properties in various systems from artificial membranes to cells: It benefits from a high sensitivity to local properties such as polarity and molecular orientational order, with a high spatial resolution down to the single-molecule level. The influence of embedded fluorescent lipid probes on the lipid membrane molecules is however poorly known and relies most often on molecular dynamics simulations, due to the challenges faced by experimental approaches to address the molecular-scale dimension of this question. In this work we develop an optical microscopy imaging method to probe the effect of fluorophores embedded in the membrane as lipid probes, on their lipid environment, with a lateral resolution of a few hundreds of nanometers. We combine polarized-nonlinear microscopy contrasts that can independently address the lipid probe, by polarized two-photon fluorescence, and the membrane lipids, by polarized coherent Raman scattering. Using trimethylamino derivative 1-(4-trimethylammonium-phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) and di-8-butyl-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS) as model probes, we show that both probes tend to induce an orientational disorder of their surrounding lipid CH-bonds in 1,2-dipalmitoylphosphatidylcholine (DPPC) lipids environments, while there is no noticeable effect in more disordered 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid membranes.
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Affiliation(s)
- Paulina Gasecka
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
| | - Naveen K Balla
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
| | - Miguel Sison
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
| | - Sophie Brasselet
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
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5
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Hitaishi P, Mandal P, Ghosh SK. Partitioning of a Hybrid Lipid in Domains of Saturated and Unsaturated Lipids in a Model Cellular Membrane. ACS OMEGA 2021; 6:34546-34554. [PMID: 34963939 PMCID: PMC8697375 DOI: 10.1021/acsomega.1c04835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/30/2021] [Indexed: 06/14/2023]
Abstract
The cellular membranes are composed of hundreds of components such as lipids, proteins, and sterols that are chemically and physically distinct from each other. The lipid-lipid and lipid-protein interactions form domains in this membrane, which play vital roles in membrane physiology. The hybrid lipids (HLs) with one saturated and one unsaturated chain can control the shape and size of these domains, ensuring the thermodynamic stability of a membrane. In this study, the thermodynamics of mixing of a HL and its structural effects on the phase separated domains in a model membrane composed of a saturated and an unsaturated lipid have been investigated. The HL is observed to mix into an unsaturated lipid reducing the Gibbs free energy, whereas the mixing is unfavorable in a saturated lipid. The presence of an HL in an unsaturated lipid tends to increase its area fraction, which is reflected in the enhanced correlation length across the bilayers in a multilayered sample. There is a feeble effect on the domain structure of the saturated lipid due to the presence of the HLs at the phase boundary. This study concludes that the HLs preferentially participate in the unsaturated lipid regions compared to that of a saturated lipid.
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6
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Mahato J, Ray KK, Das S, Kadu P, Maji SK, Chowdhury A. Investigation of Structural Heterogeneity in Individual Amyloid Fibrils Using Polarization-Resolved Microscopy. J Phys Chem B 2021; 125:13406-13414. [PMID: 34861110 DOI: 10.1021/acs.jpcb.1c08604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Amyloid fibrils are structurally heterogeneous protein aggregates that are implicated in a wide range of neurodegenerative and other proteopathic diseases. These fibrils exist in a variety of different tertiary and higher-level structures, and this exhibited polymorphism greatly complicates any structural study of amyloid fibrils. In this work, we demonstrate a method of using polarization-resolved microscopy to directly observe the structural heterogeneity of individual amyloid fibrils using amyloid-bound fluorophores. We formulate a mathematical quantity, helical anisotropy, which utilizes the polarized emission of amyloid-bound fluorophores to report on the local structure of individual fibrils. Using this method, we show how model amyloid fibrils generated from short peptides exhibit diverse structural properties both between different fibrils and within a single fibril, in a manner that is replicated for fibrils assembled from longer proteins. Our method represents an accessible and easily adaptable technique by which polymorphism in the structure of amyloid fibrils can be probed. Additionally, the methodology we describe here can be easily extended to the study of other fibrillar and otherwise ordered supramolecular structures.
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Affiliation(s)
- Jaladhar Mahato
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Korak Kumar Ray
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Subhadeep Das
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Pradeep Kadu
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Samir K Maji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Arindam Chowdhury
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
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7
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ESCRT-III induces phase separation in model membranes prior to budding and causes invagination of the liquid-ordered phase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183689. [PMID: 34224704 DOI: 10.1016/j.bbamem.2021.183689] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 06/05/2021] [Accepted: 06/27/2021] [Indexed: 11/21/2022]
Abstract
Membrane fission triggered by the endosomal sorting complex required for transport (ESCRT) is an important process observed in several pathogenic and non-pathogenic cellular events. From a synthetic-biology viewpoint, ESCRT proteins represent an interesting machinery for the construction of cell mimetic sub-compartments produced by fission. Since their discovery, the studies on ESCRT-III-mediated action, have mainly focused on protein dynamics, ignoring the role of lipid organization and membrane phase state. Recently, it has been suggested that membrane buds formed by the action of ESCRT-III are generated from transient microdomains in endosomal membranes. However, the interplay between membrane domain formation and ESCRT remodeling pathways has not been investigated. Here, giant unilamellar vesicles made of ternary lipid mixtures, either homogeneous in phase or exhibiting liquid-ordered/liquid-disordered phase coexistence, were employed as a model membrane system. These vesicles were incubated with purified recombinant ESCRT-III proteins from the parasite Entamoeba histolytica. In homogeneous membranes, we observe that EhVps32 can trigger domain formation while EhVps20 preferentially co-localizes in the liquid disordered phase. The addition of EhVps24 appears to induce the formation of intraluminal vesicles produced from the liquid-ordered phase. In phase separated membranes, the intraluminal vesicles are also generated from the liquid-ordered phase and presumably emerge from the phase boundary region. Our findings reinforce the hypothesis that ESCRT-mediated remodeling depends on the membrane phase state. Furthermore, the obtained results point to a potential synthetic biology approach for establishing eukaryotic mimics of artificial cells with microcompartments of specific membrane composition, which can also differ from that of the mother vesicle.
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8
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Wetting regulates autophagy of phase-separated compartments and the cytosol. Nature 2021; 591:142-146. [DOI: 10.1038/s41586-020-2992-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/28/2020] [Indexed: 01/19/2023]
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9
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Osella S, Knippenberg S. Laurdan as a Molecular Rotor in Biological Environments. ACS APPLIED BIO MATERIALS 2019; 2:5769-5778. [DOI: 10.1021/acsabm.9b00789] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Stefan Knippenberg
- RCPTM, Department of Physical Chemistry, Fac. Sciences, Palacký University, 771 46 Olomouc, Czech Republic
- Theoretical Physics, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
- Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden
- Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
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10
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Dimova R. Giant Vesicles and Their Use in Assays for Assessing Membrane Phase State, Curvature, Mechanics, and Electrical Properties. Annu Rev Biophys 2019; 48:93-119. [DOI: 10.1146/annurev-biophys-052118-115342] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Giant unilamellar vesicles represent a promising and extremely useful model biomembrane system for systematic measurements of mechanical, thermodynamic, electrical, and rheological properties of lipid bilayers as a function of membrane composition, surrounding media, and temperature. The most important advantage of giant vesicles over other model membrane systems is that the membrane responses to external factors such as ions, (macro)molecules, hydrodynamic flows, or electromagnetic fields can be directly observed under the microscope. Here, we briefly review approaches for giant vesicle preparation and describe several assays used for deducing the membrane phase state and measuring a number of material properties, with further emphasis on membrane reshaping and curvature.
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Affiliation(s)
- Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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11
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Mohapatra M, Mishra AK. Excited state proton transfer based fluorescent molecular probes and their application in studying lipid bilayer membranes. Photochem Photobiol Sci 2019; 18:2830-2848. [DOI: 10.1039/c9pp00294d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The distribution and prototropic equilibria of 1-naphthol (NpOH) in lipid bilayer membrane.
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Affiliation(s)
| | - Ashok Kumar Mishra
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600036
- India
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12
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Cholesterol modulates curcumin partitioning and membrane effects. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2320-2328. [DOI: 10.1016/j.bbamem.2018.05.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 05/14/2018] [Accepted: 05/30/2018] [Indexed: 12/19/2022]
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13
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Pick H, Alves AC, Vogel H. Single-Vesicle Assays Using Liposomes and Cell-Derived Vesicles: From Modeling Complex Membrane Processes to Synthetic Biology and Biomedical Applications. Chem Rev 2018; 118:8598-8654. [PMID: 30153012 DOI: 10.1021/acs.chemrev.7b00777] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The plasma membrane is of central importance for defining the closed volume of cells in contradistinction to the extracellular environment. The plasma membrane not only serves as a boundary, but it also mediates the exchange of physical and chemical information between the cell and its environment in order to maintain intra- and intercellular functions. Artificial lipid- and cell-derived membrane vesicles have been used as closed-volume containers, representing the simplest cell model systems to study transmembrane processes and intracellular biochemistry. Classical examples are studies of membrane translocation processes in plasma membrane vesicles and proteoliposomes mediated by transport proteins and ion channels. Liposomes and native membrane vesicles are widely used as model membranes for investigating the binding and bilayer insertion of proteins, the structure and function of membrane proteins, the intramembrane composition and distribution of lipids and proteins, and the intermembrane interactions during exo- and endocytosis. In addition, natural cell-released microvesicles have gained importance for early detection of diseases and for their use as nanoreactors and minimal protocells. Yet, in most studies, ensembles of vesicles have been employed. More recently, new micro- and nanotechnological tools as well as novel developments in both optical and electron microscopy have allowed the isolation and investigation of individual (sub)micrometer-sized vesicles. Such single-vesicle experiments have revealed large heterogeneities in the structure and function of membrane components of single vesicles, which were hidden in ensemble studies. These results have opened enormous possibilities for bioanalysis and biotechnological applications involving unprecedented miniaturization at the nanometer and attoliter range. This review will cover important developments toward single-vesicle analysis and the central discoveries made in this exciting field of research.
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Affiliation(s)
- Horst Pick
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Ana Catarina Alves
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Horst Vogel
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
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14
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Shishina AK, Kovrigina EA, Galiakhmetov AR, Rathore R, Kovrigin EL. Study of Förster Resonance Energy Transfer to Lipid Domain Markers Ascertains Partitioning of Semisynthetic Lipidated N-Ras in Lipid Raft Nanodomains. Biochemistry 2018; 57:872-881. [PMID: 29280621 DOI: 10.1021/acs.biochem.7b01181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cellular membranes are heterogeneous planar lipid bilayers displaying lateral phase separation with the nanometer-scale liquid-ordered phase (also known as "lipid rafts") surrounded by the liquid-disordered phase. Many membrane-associated proteins were found to permanently integrate into the lipid rafts, which is critical for their biological function. Isoforms H and N of Ras GTPase possess a unique ability to switch their lipid domain preference depending on the type of bound guanine nucleotide (GDP or GTP). This behavior, however, has never been demonstrated in vitro in model bilayers with recombinant proteins and therefore has been attributed to the action of binding of Ras to other proteins at the membrane surface. In this paper, we report the observation of the nucleotide-dependent switch of lipid domain preferences of the semisynthetic lipidated N-Ras in lipid raft vesicles in the absence of additional proteins. To detect segregation of Ras molecules in raft and disordered lipid domains, we measured Förster resonance energy transfer between the donor fluorophore, mant, attached to the protein-bound guanine nucleotides, and the acceptor, rhodamine-conjugated lipid, localized into the liquid-disordered domains. Herein, we established that N-Ras preferentially populated raft domains when bound to mant-GDP, while losing its preference for rafts when it was associated with a GTP mimic, mant-GppNHp. At the same time, the isolated lipidated C-terminal peptide of N-Ras was found to be localized outside of the liquid-ordered rafts, most likely in the bulk-disordered lipid. Substitution of the N-terminal G domain of N-Ras with a homologous G domain of H-Ras disrupted the nucleotide-dependent lipid domain switch.
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Affiliation(s)
- Anna K Shishina
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Elizaveta A Kovrigina
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Azamat R Galiakhmetov
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Rajendra Rathore
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Evgenii L Kovrigin
- Chemistry Department, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201, United States
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15
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Grudzinski W, Sagan J, Welc R, Luchowski R, Gruszecki WI. Molecular organization, localization and orientation of antifungal antibiotic amphotericin B in a single lipid bilayer. Sci Rep 2016; 6:32780. [PMID: 27620838 PMCID: PMC5020354 DOI: 10.1038/srep32780] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/15/2016] [Indexed: 01/29/2023] Open
Abstract
Amphotericin B is a popular antifungal antibiotic, a gold standard in treatment of systemic mycotic infections, due to its high effectiveness. On the other hand, applicability of the drug is limited by its considerable toxicity to patients. Biomembranes are a primary target of physiological activity of amphotericin B and both the pharmacologically desired and toxic side effects of the drug relay on its molecular organization in the lipid phase. In the present work, molecular organization, localization and orientation of amphotericin B, in a single lipid bilayer system, was analysed simultaneously, thanks to application of a confocal fluorescence lifetime imaging microscopy of giant unilamellar vesicles. The results show that the presence of sterols, in the lipid phase, promotes formation of supramolecular structures of amphotericin B and their penetration into the membrane hydrophobic core. The fact that such an effect is substantially less pronounced in the case of cholesterol than ergosterol, the sterol of fungal membranes, provides molecular insight into the selectivity of the drug.
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Affiliation(s)
- Wojciech Grudzinski
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
| | - Joanna Sagan
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
| | - Renata Welc
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
| | - Rafal Luchowski
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
| | - Wieslaw I Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland
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16
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Arends F, Chaudhary H, Janmey P, Claessens MMAE, Lieleg O. Lipid Head Group Charge and Fatty Acid Configuration Dictate Liposome Mobility in Neurofilament Networks. Macromol Biosci 2016; 17. [DOI: 10.1002/mabi.201600229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/09/2016] [Indexed: 01/26/2023]
Affiliation(s)
- Fabienna Arends
- Department of Mechanical Engineering and Institute of Medical Engineering (IMETUM); Technical University of Munich; 85748 Garching Germany
| | - Himanshu Chaudhary
- Nanobiophysics group; MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine; University of Twente; 7500 AE Enschede The Netherlands
| | - Paul Janmey
- Institute for Medicine and Engineering; University of Pennsylvania; Philadelphia PA 19104 USA
| | - Mireille M. A. E. Claessens
- Nanobiophysics group; MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine; University of Twente; 7500 AE Enschede The Netherlands
| | - Oliver Lieleg
- Department of Mechanical Engineering and Institute of Medical Engineering (IMETUM); Technical University of Munich; 85748 Garching Germany
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17
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do Canto AMTM, Robalo JR, Santos PD, Carvalho AJP, Ramalho JPP, Loura LMS. Diphenylhexatriene membrane probes DPH and TMA-DPH: A comparative molecular dynamics simulation study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2647-2661. [PMID: 27475296 DOI: 10.1016/j.bbamem.2016.07.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/05/2016] [Accepted: 07/25/2016] [Indexed: 10/21/2022]
Abstract
Fluorescence spectroscopy and microscopy have been utilized as tools in membrane biophysics for decades now. Because phospholipids are non-fluorescent, the use of extrinsic membrane probes in this context is commonplace. Among the latter, 1,6-diphenylhexatriene (DPH) and its trimethylammonium derivative (TMA-DPH) have been extensively used. It is widely believed that, owing to its additional charged group, TMA-DPH is anchored at the lipid/water interface and reports on a bilayer region that is distinct from that of the hydrophobic DPH. In this study, we employ atomistic MD simulations to characterize the behavior of DPH and TMA-DPH in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and POPC/cholesterol (4:1) bilayers. We show that although the dynamics of TMA-DPH in these membranes is noticeably more hindered than that of DPH, the location of the average fluorophore of TMA-DPH is only ~3-4Å more shallow than that of DPH. The hindrance observed in the translational and rotational motions of TMA-DPH compared to DPH is mainly not due to significant differences in depth, but to the favorable electrostatic interactions of the former with electronegative lipid atoms instead. By revealing detailed insights on the behavior of these two probes, our results are useful both in the interpretation of past work and in the planning of future experiments using them as membrane reporters.
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Affiliation(s)
- António M T M do Canto
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - João R Robalo
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal; Theory and Bio-Systems Department, Max Planck Institute of Colloids and Interfaces, Wissenschaftspark Golm, D-14424 Potsdam, Germany
| | - Patrícia D Santos
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - Alfredo J Palace Carvalho
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - J P Prates Ramalho
- Centro de Química de Évora e Departamento de Química, Escola de Ciências e Tecnologia, Colégio Luís Verney, Rua Romão Ramalho 59, P-7002-554 Évora, Portugal
| | - Luís M S Loura
- Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, P-3000-548 Coimbra, Portugal; Centro de Química de Coimbra, Largo D. Dinis, Rua Larga, P-3004-535 Coimbra, Portugal.
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18
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Börner R, Ehrlich N, Hohlbein J, Hübner CG. Single Molecule 3D Orientation in Time and Space: A 6D Dynamic Study on Fluorescently Labeled Lipid Membranes. J Fluoresc 2016; 26:963-75. [DOI: 10.1007/s10895-016-1784-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 03/02/2016] [Indexed: 10/22/2022]
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The nanoscale organization of signaling domains at the plasma membrane. CURRENT TOPICS IN MEMBRANES 2015; 75:125-65. [PMID: 26015282 DOI: 10.1016/bs.ctm.2015.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this chapter, we present an overview of the role of the nanoscale organization of signaling domains in regulating key cellular processes. In particular, we illustrate the importance of protein and lipid nanodomains as triggers and mediators of cell signaling. As particular examples, we summarize the state of the art of understanding the role of nanodomains in the mounting of an immune response, cellular adhesion, intercellular communication, and cell proliferation. Thus, this chapter underlines the essential role the nanoscale organization of key signaling proteins and lipid domains. We will also see how nanodomains play an important role in the lifecycle of many pathogens relevant to human disease and therefore illustrate how these structures may become future therapeutic targets.
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20
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Ferrand P, Gasecka P, Kress A, Wang X, Bioud FZ, Duboisset J, Brasselet S. Ultimate use of two-photon fluorescence microscopy to map orientational behavior of fluorophores. Biophys J 2015; 106:2330-9. [PMID: 24896112 DOI: 10.1016/j.bpj.2014.04.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/28/2014] [Accepted: 04/08/2014] [Indexed: 11/25/2022] Open
Abstract
The orientational distribution of fluorophores is an important reporter of the structure and function of their molecular environment. Although this distribution affects the fluorescence signal under polarized-light excitation, its retrieval is limited to a small number of parameters. Because of this limitation, the need for a geometrical model (cone, Gaussian, etc.) to effect such retrieval is often invoked. In this work, using a symmetry decomposition of the distribution function of the fluorescent molecules, we show that polarized two-photon fluorescence based on tunable linear dichroism allows for the retrieval of this distribution with reasonable fidelity and without invoking either an a priori knowledge of the system to be investigated or a geometrical model. We establish the optimal level of detail to which any distribution can be retrieved using this technique. As applied to artificial lipid vesicles and cell membranes, the ability of this method to identify and quantify specific structural properties that complement the more traditional molecular-order information is demonstrated. In particular, we analyze situations that give access to the sharpness of the angular constraint, and to the evidence of an isotropic population of fluorophores within the focal volume encompassing the membrane. Moreover, this technique has the potential to address complex situations such as the distribution of a tethered membrane protein label in an ordered environment.
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Affiliation(s)
- Patrick Ferrand
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille, France.
| | - Paulina Gasecka
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille, France
| | - Alla Kress
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille, France
| | - Xiao Wang
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille, France
| | - Fatma-Zohra Bioud
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille, France
| | - Julien Duboisset
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille, France
| | - Sophie Brasselet
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille, France
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21
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Demchenko AP, Duportail G, Oncul S, Klymchenko AS, Mély Y. Introduction to fluorescence probing of biological membranes. Methods Mol Biol 2015; 1232:19-43. [PMID: 25331125 DOI: 10.1007/978-1-4939-1752-5_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fluorescence is one of the most powerful and commonly used tools in biophysical studies of biomembrane structure and dynamics that can be applied on different levels, from lipid monolayers and bilayers to living cells, tissues, and whole animals. Successful application of this method relies on proper design of fluorescence probes with optimized photophysical properties. These probes are efficient for studying the microscopic analogs of viscosity, polarity, and hydration, as well as the molecular order, environment relaxation, and electrostatic potentials at the sites of their location. Being smaller than the membrane width they can sense the gradients of these parameters across the membrane. We present examples of novel dyes that achieve increased spatial resolution and information content of the probe responses. In this respect, multiparametric environment-sensitive probes feature considerable promise.
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Affiliation(s)
- Alexander P Demchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01030, Ukraine,
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22
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Klymchenko AS, Kreder R. Fluorescent probes for lipid rafts: from model membranes to living cells. ACTA ACUST UNITED AC 2013; 21:97-113. [PMID: 24361047 DOI: 10.1016/j.chembiol.2013.11.009] [Citation(s) in RCA: 335] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/22/2013] [Accepted: 11/04/2013] [Indexed: 01/10/2023]
Abstract
Membrane microdomains (rafts) remain one of the controversial issues in biophysics. Fluorescent molecular probes, which make these lipid nanostructures visible through optical techniques, are one of the tools currently used to study lipid rafts. The most common are lipophilic fluorescent probes that partition specifically into liquid ordered or liquid disordered phase. Their partition depends on the lipid composition of a given phase, which complicates their use in cellular membranes. A second class of probes is based on environment-sensitive dyes, which partition into both phases, but stain them by different fluorescence color, intensity, or lifetime. These probes can directly address the properties of each separate phase, but their cellular applications are still limited. The present review focuses on summarizing the current state in the field of developing and applying fluorescent molecular probes to study lipid rafts. We highlight an urgent need to develop new probes, specifically adapted for cell plasma membranes and compatible with modern fluorescence microscopy techniques to push the understanding of membrane microdomains forward.
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Affiliation(s)
- Andrey S Klymchenko
- Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401 ILLKIRCH, France.
| | - Rémy Kreder
- Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401 ILLKIRCH, France
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23
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Brasselet S, Ferrand P, Kress A, Wang X, Ranchon H, Gasecka A. Imaging Molecular Order in Cell Membranes by Polarization-Resolved Fluorescence Microscopy. SPRINGER SERIES ON FLUORESCENCE 2012. [DOI: 10.1007/4243_2012_51] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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24
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Probing orientational behavior of MHC class I protein and lipid probes in cell membranes by fluorescence polarization-resolved imaging. Biophys J 2011; 101:468-76. [PMID: 21767500 DOI: 10.1016/j.bpj.2011.05.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Revised: 05/06/2011] [Accepted: 05/11/2011] [Indexed: 11/20/2022] Open
Abstract
Steady-state polarization-resolved fluorescence imaging is used to analyze the molecular orientational order behavior of rigidly labeled major histocompatibility complex class I (MHC I) proteins and lipid probes in cell membranes of living cells. These fluorescent probes report the orientational properties of proteins and their surrounding lipid environment. We present a statistical study of the molecular orientational order, modeled as the width of the angular distribution of the molecules, for the proteins in the cell endomembrane and plasma membrane, as well as for the lipid probes in the plasma membrane. We apply this methodology on cells after treatments affecting the actin and microtubule networks. We find in particular opposite orientational order changes of proteins and lipid probes in the plasma membrane as a response to the cytoskeleton disruption. This suggests that MHC I orientational order is governed by its interaction with the cytoskeleton, whereas the plasma membrane lipid order is governed by the local cell membrane morphology.
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25
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Heberle FA, Feigenson GW. Phase separation in lipid membranes. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a004630. [PMID: 21441593 DOI: 10.1101/cshperspect.a004630] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cell membranes show complex behavior, in part because of the large number of different components that interact with each other in different ways. One aspect of this complex behavior is lateral organization of components on a range of spatial scales. We found that lipid-only mixtures can model the range of size scales, from approximately 2 nm up to microns. Furthermore, the size of compositional heterogeneities can be controlled entirely by lipid composition for mixtures such as 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/cholesterol or sphingomyelin (SM)/DOPC/POPC/cholesterol. In one region of special interest, because of its connection to cell membrane rafts, nanometer-scale domains of liquid-disordered phase and liquid-ordered phase coexist over a wide range of compositions.
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Affiliation(s)
- Frederick A Heberle
- Department of Molecular Biology and Genetics, Field of Biophysics, Cornell University, Ithaca, New York 14853, USA
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26
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Tumaneng PW, Pandit SA, Zhao G, Scott HL. Self-consistent mean-field model for palmitoyloleoylphosphatidylcholine-palmitoyl sphingomyelin-cholesterol lipid bilayers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:031925. [PMID: 21517541 PMCID: PMC3397247 DOI: 10.1103/physreve.83.031925] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 01/13/2011] [Indexed: 05/30/2023]
Abstract
The connection between membrane inhomogeneity and the structural basis of lipid rafts has sparked interest in the lateral organization of model lipid bilayers of two and three components. In an effort to investigate anisotropic lipid distribution in mixed bilayers, a self-consistent mean-field theoretical model is applied to palmitoyloleoylphosphatidylcholine (POPC)--palmitoyl sphingomyelin (PSM)--cholesterol mixtures. The compositional dependence of lateral organization in these mixtures is mapped onto a ternary plot. The model utilizes molecular dynamics simulations to estimate interaction parameters and to construct chain conformation libraries. We find that at some concentration ratios the bilayers separate spatially into regions of higher and lower chain order coinciding with areas enriched with PSM and POPC, respectively. To examine the effect of the asymmetric chain structure of POPC on bilayer lateral inhomogeneity, we consider POPC-lipid interactions with and without angular dependence. Results are compared with experimental data and with results from a similar model for mixtures of dioleoylphosphatidylcholine, steroyl sphingomyelin, and cholesterol.
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Affiliation(s)
- Paul W Tumaneng
- Department of Biological, Chemical and Physical Sciences and Center for the Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois 60616, USA
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27
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A Multiparametric Fluorescence Approach for Biomembrane Studies. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/b978-0-12-387721-5.00005-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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28
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Farkas ER, Webb WW. Multiphoton polarization imaging of steady-state molecular order in ternary lipid vesicles for the purpose of lipid phase assignment. J Phys Chem B 2010; 114:15512-22. [PMID: 21058681 DOI: 10.1021/jp107025h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have investigated lipid acyl chain order parameters of giant unilamellar vesicles (GUVs) using multiphoton fluorescence microscopy. We compare two widely used models of lipid acyl chain order parameters: the "wobble-on-a-cone" model and the Gaussian distribution model. For the first time, we systematically address a ternary system for which the phase diagram encompassing both composition and temperature space has been mapped in order to determine tie-line directions and thus phase assignment. In addition, because miscibility and chain melting transitions can be observed directly and simultaneously with multiphoton microscopy, our technique is applicable to determining the extent of the coupling between chain order and miscibility; thus, it provides a more robust platform for comparison with theory.
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Affiliation(s)
- Elaine R Farkas
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States
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29
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Botchway SW, Lewis AM, Stubbs CD. Development of fluorophore dynamics imaging as a probe for lipid domains in model vesicles and cell membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2010; 40:131-41. [PMID: 20953783 DOI: 10.1007/s00249-010-0631-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 09/27/2010] [Accepted: 09/28/2010] [Indexed: 11/28/2022]
Abstract
The ability to detect raft structures in membranes continues to present a problem, especially in the membranes of live cells. Rafts, generally considered to be small (< 200 nm) sphingolipid-rich regions, are commonly modelled using lipid vesicle systems where the ability of fluorophore-labelled lipids to preferentially locate into domains (basically large rafts) is investigated. Instead, in this study the motional properties of different fluorophores were determined using two-photon excitation and time-correlated single-photon counting coupled with diffraction-limited imaging with polarizing optics in scanning mode to obtain nanosecond rotational correlation time images. To develop the method, well-characterized domain-containing models consisting of giant unilamellar vesicles comprising mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, sphingomyelin and cholesterol were used with the fluorophores diphenylhexatriene, 1-palmitoyl-2-{6-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]hexanoyl}-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl). Accordingly, images of rotational correlation times of the probes revealed domain structures for all three probes consistent with other studies using different approaches. Rotational correlation time images of living cell membranes were also observed. The method has the advantage that not only does it enable domains to be visualised or imaged in a unique manner but that it can also potentially provide useful information on the lipid dynamics within the structures.
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Affiliation(s)
- Stanley W Botchway
- Lasers for Science, Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX110QX, UK
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30
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Kucherak OA, Oncul S, Darwich Z, Yushchenko DA, Arntz Y, Didier P, Mély Y, Klymchenko AS. Switchable nile red-based probe for cholesterol and lipid order at the outer leaflet of biomembranes. J Am Chem Soc 2010; 132:4907-16. [PMID: 20225874 DOI: 10.1021/ja100351w] [Citation(s) in RCA: 290] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cholesterol and sphingomyelin form together a highly ordered membrane phase, which is believed to play important biological functions in plasma membranes of mammalian cells. Since sphingomyelin is present mainly at the outer leaflet of cell membranes, monitoring its lipid order requires molecular probes capable to bind specifically at this leaflet and exhibit negligibly slow flip-flop. In the present work, such a probe was developed by modifying the solvatochromic fluorescent dye Nile Red with an amphiphilic anchor group. To evaluate the flip-flop of the obtained probe (NR12S), we developed a methodology of reversible redox switching of its fluorescence at one leaflet using sodium dithionite. This method shows that NR12S, in contrast to parent Nile Red, binds exclusively the outer membrane leaflet of model lipid vesicles and living cells with negligible flip-flop in the time scale of hours. Moreover, the emission maximum of NR12S in model vesicles exhibits a significant blue shift in liquid ordered phase (sphingomyelin-cholesterol) as compared to liquid disordered phase (unsaturated phospholipids). As a consequence, these two phases could be clearly distinguished in NR12S-stained giant vesicles by fluorescence microscopy imaging of intensity ratio between the blue and red parts of the probe emission spectrum. Being added to living cells, NR12S binds predominantly, if not exclusively, their plasma membranes and shows an emission spectrum intermediate between those in liquid ordered and disordered phases of model membranes. Importantly, the emission color of NR12S correlates well with the cholesterol content in cell membranes, which allows monitoring the cholesterol depletion process with methyl-beta-cyclodextrin by fluorescence spectroscopy and microscopy. The attractive photophysical and switching properties of NR12S, together with its selective outer leaflet staining and sensitivity to cholesterol and lipid order, make it a new powerful tool for studying model and cell membranes.
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Affiliation(s)
- Oleksandr A Kucherak
- Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401 Illkirch Cedex, France
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31
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Liquid ordered phase in cell membranes evidenced by a hydration-sensitive probe: Effects of cholesterol depletion and apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1436-43. [DOI: 10.1016/j.bbamem.2010.01.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 12/14/2009] [Accepted: 01/14/2010] [Indexed: 02/07/2023]
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32
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Stöckl M, Herrmann A. Detection of lipid domains in model and cell membranes by fluorescence lifetime imaging microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1444-56. [DOI: 10.1016/j.bbamem.2009.12.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 11/30/2009] [Accepted: 12/21/2009] [Indexed: 01/17/2023]
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33
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Impact of membrane-anchored fluorescent probes on the mechanical properties of lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1333-7. [DOI: 10.1016/j.bbamem.2010.03.026] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/30/2010] [Accepted: 03/31/2010] [Indexed: 12/19/2022]
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34
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Oreopoulos J, Epand RF, Epand RM, Yip CM. Peptide-induced domain formation in supported lipid bilayers: direct evidence by combined atomic force and polarized total internal reflection fluorescence microscopy. Biophys J 2010; 98:815-23. [PMID: 20197035 DOI: 10.1016/j.bpj.2009.12.4327] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 11/25/2009] [Accepted: 12/09/2009] [Indexed: 12/01/2022] Open
Abstract
Direct visualization of the mechanism(s) by which peptides induce localized changes to the structure of membranes has high potential for enabling understanding of the structure-function relationship in antimicrobial and cell-penetrating peptides. We have applied a combined imaging strategy to track the interaction of a model antimicrobial peptide, PFWRIRIRR-amide, with bacterial membrane-mimetic supported phospholipid bilayers comprised of POPE/TOCL. Our in situ studies revealed rapid reorganization of the POPE/TOCL membrane into localized TOCL-rich domains with a concomitant change in the organization of the membranes themselves, as reflected by changes in fluorescent-membrane-probe order parameter, upon introduction of the peptide.
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Affiliation(s)
- John Oreopoulos
- Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada
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35
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Gasecka A, Han TJ, Favard C, Cho BR, Brasselet S. Quantitative imaging of molecular order in lipid membranes using two-photon fluorescence polarimetry. Biophys J 2010; 97:2854-62. [PMID: 19917241 DOI: 10.1016/j.bpj.2009.08.052] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 08/18/2009] [Accepted: 08/28/2009] [Indexed: 11/26/2022] Open
Abstract
We present a polarimetric two-photon microscopy technique to quantitatively image the local static molecular orientational behavior in lipid and cell membranes. This approach, based on a tunable excitation polarization state complemented by a polarized readout, is easily implementable and does not require hypotheses on the molecular angular distribution such as its mean orientation, which is a main limitation in traditional fluorescence anisotropy measurements. The method is applied to the investigation of the molecular angular distribution in giant unilamellar vesicles formed by liquid-ordered and liquid-disordered micro-domains, and in COS-7 cell membranes. The highest order contrast between ordered and disordered domains is obtained for dyes locating within the membrane acyl chains.
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Affiliation(s)
- Alicja Gasecka
- Institut Fresnel-MOSAIC Group, UMR 6133, Centre National de la Recherche Scientifique, Université Aix Marseille III, Domaine Universitaire St Jerome, Marseille, France
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36
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Tumaneng PW, Pandit SA, Zhao G, Scott HL. Lateral organization of complex lipid mixtures from multiscale modeling. J Chem Phys 2010; 132:065104. [PMID: 20151760 PMCID: PMC2833188 DOI: 10.1063/1.3314729] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 01/20/2010] [Indexed: 11/14/2022] Open
Abstract
The organizational properties of complex lipid mixtures can give rise to functionally important structures in cell membranes. In model membranes, ternary lipid-cholesterol (CHOL) mixtures are often used as representative systems to investigate the formation and stabilization of localized structural domains ("rafts"). In this work, we describe a self-consistent mean-field model that builds on molecular dynamics simulations to incorporate multiple lipid components and to investigate the lateral organization of such mixtures. The model predictions reveal regions of bimodal order on ternary plots that are in good agreement with experiment. Specifically, we have applied the model to ternary mixtures composed of dioleoylphosphatidylcholine:18:0 sphingomyelin:CHOL. This work provides insight into the specific intermolecular interactions that drive the formation of localized domains in these mixtures. The model makes use of molecular dynamics simulations to extract interaction parameters and to provide chain configuration order parameter libraries.
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Affiliation(s)
- Paul W Tumaneng
- Department of Biological, Chemical and Physical Sciences and Center for the Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
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37
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Ariola FS, Li Z, Cornejo C, Bittman R, Heikal AA. Membrane fluidity and lipid order in ternary giant unilamellar vesicles using a new bodipy-cholesterol derivative. Biophys J 2009; 96:2696-708. [PMID: 19348752 DOI: 10.1016/j.bpj.2008.12.3922] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 12/11/2008] [Accepted: 12/17/2008] [Indexed: 11/24/2022] Open
Abstract
Cholesterol-rich, liquid-ordered (L(o)) domains are believed to be biologically relevant, and yet detailed knowledge about them, especially in live cells under physiological conditions, is elusive. Although these domains have been observed in model membranes, understanding cholesterol-lipid interactions at the molecular level, under controlled lipid mixing, remains a challenge. Further, although there are a number of fluorescent lipid analogs that partition into liquid-disordered (L(d)) domains, the number of such analogs with a high affinity for biologically relevant L(o) domains is limited. Here, we use a new Bodipy-labeled cholesterol (Bdp-Chol) derivative to investigate membrane fluidity, lipid order, and partitioning in various lipid phases in giant unilamellar vesicles (GUVs) as a model system. GUVs were prepared from mixtures of various molar fractions of dioleoylphosphatidylcholine, cholesterol, and egg sphingomyelin. The L(d) phase domains were also labeled with 1,1'-didodecyl-3,3,3',3'-tetramethylindocarbocyanine (DiI-C(12)) for comparison. Two-photon fluorescence lifetime and anisotropy imaging of Bdp-Chol are sensitive to lipid phase domains in GUVs. The fluorescence lifetime of Bdp-Chol in liquid-disordered, single-phase GUVs is 5.50 +/- 0.08 ns, compared with 4.1 +/- 0.4 ns in the presence of DiI-C(12). The observed reduction of fluorescence lifetime is attributed to Förster resonance energy transfer between Bdp-Chol (a donor) and DiI-C(12) (an acceptor) with an estimated efficiency of 0.25 and donor-acceptor distance of 2.6 +/- 0.2 nm. These results also indicate preferential partitioning (K(p) = 1.88) of Bdp-Chol into the L(o) phase. One-photon, time-resolved fluorescence anisotropy of Bdp-Chol decays as a triexponential in the lipid bilayer with an average rotational diffusion coefficient, lipid order parameter, and membrane fluidity that are sensitive to phase domains. The translational diffusion coefficient of Bdp-Chol, as measured using fluorescence correlation spectroscopy, is (7.4 +/- 0.3) x 10(-8) cm(2)/s and (5.0 +/- 0.2) x 10(-8) cm(2)/s in the L(d) and L(o) phases, respectively. Experimental translational/rotational diffusion coefficient ratios are compared with theoretical predictions using the hydrodynamic model (Saffman-Delbrück). The results suggest that Bdp-Chol is likely to form a complex with other lipid molecules during its macroscopic diffusion in GUV lipid bilayers at room temperature. Our integrated, multiscale results demonstrate the potential of this cholesterol analog for studying lipid-lipid interactions, lipid order, and membrane fluidity of biologically relevant L(o) domains.
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Affiliation(s)
- Florly S Ariola
- Department of Bioengineering, The Pennsylvania State University, University Park, Pennsylvania, USA
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