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Pandey Y, Ingold A, Kumar N, Zenobi R. Nanoscale visualization of phase separation in binary supported lipid monolayer using tip-enhanced Raman spectroscopy. NANOSCALE 2024; 16:10578-10583. [PMID: 38767416 PMCID: PMC11154864 DOI: 10.1039/d4nr00816b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/05/2024] [Indexed: 05/22/2024]
Abstract
Supported lipid membranes are an important model system to study the phase separation behavior at the nanoscale. However, the conventional nanoanalytical tools often fail to provide reliable chemical characterization of the phase separated domains in a non-destructive and label-free manner. This study demonstrates the application of scanning tunneling microscopy-based tip-enhanced Raman spectroscopy (TERS) to study the nanoscale phase separation in supported d62-DPPC : DOPC lipid monolayers. Hyperspectral TERS imaging successfully revealed a clear segregation of the d62-DPPC-rich and DOPC-rich domains. Interestingly, nanoscale deposits of d62-DPPC were observed inside the DOPC-rich domains and vice versa. High-resolution TERS imaging also revealed the presence of a 40-120 nm wide interfacial region between the d62-DPPC-rich and DOPC-rich domains signifying a smooth transition rather than a sharp boundary between them. The novel insights obtained in this study demonstrate the effectiveness of TERS in studying binary lipid monolayers at the nanoscale.
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Affiliation(s)
- Yashashwa Pandey
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
| | - Andrea Ingold
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
| | - Naresh Kumar
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
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Okamoto Y, Hamaguchi K, Watanabe M, Watanabe N, Umakoshi H. Characterization of Phase Separated Planar Lipid Bilayer Membrane by Fluorescence Ratio Imaging and Scanning Probe Microscope. MEMBRANES 2022; 12:770. [PMID: 36005685 PMCID: PMC9415343 DOI: 10.3390/membranes12080770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 07/27/2022] [Accepted: 07/30/2022] [Indexed: 06/15/2023]
Abstract
The lipid membrane forms nanodomains (rafts) and shows heterogeneous properties. These nanodomains relate to significant roles in various cell functions, and thus the analysis of the nanodomains in phase-separated lipid membranes is important to clarify the function and role of the nanodomains. However, the lipid membrane possesses small-sized nanodomains and shows a small height difference between the nanodomains and their surroundings at certain lipid compositions. In addition, nanodomain analysis sometimes requires highly sensitive and expensive apparatus, such as a two-photon microscope. These have prevented the analysis by the conventional fluorescence microscope and by the topography of the scanning probe microscope (SPM), even though these are promising methods in macroscale and microscale analysis, respectively. Therefore, this study aimed to overcome these problems in nanodomain analysis. We successfully demonstrated that solvatochromic dye, LipiORDER, could analyze the phase state of the lipid membrane at the macroscale with low magnification lenses. Furthermore, we could prove that the phase mode of SPM was effective in the visualization of specific nanodomains by properties difference as well as topographic images of SPM. Hence, this combination method successfully gave much information on the phase state at the micro/macro scale, and thus this would be applied to the analysis of heterogeneous lipid membranes.
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Sofińska K, Lupa D, Chachaj-Brekiesz A, Czaja M, Kobierski J, Seweryn S, Skirlińska-Nosek K, Szymonski M, Wilkosz N, Wnętrzak A, Lipiec E. Revealing local molecular distribution, orientation, phase separation, and formation of domains in artificial lipid layers: Towards comprehensive characterization of biological membranes. Adv Colloid Interface Sci 2022; 301:102614. [PMID: 35190313 DOI: 10.1016/j.cis.2022.102614] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 01/01/2023]
Abstract
Lipids, together with molecules such as DNA and proteins, are one of the most relevant systems responsible for the existence of life. Selected lipids are able to assembly into various organized structures, such as lipid membranes. The unique properties of lipid membranes determine their complex functions, not only to separate biological environments, but also to participate in regulatory functions, absorption of nutrients, cell-cell communication, endocytosis, cell signaling, and many others. Despite numerous scientific efforts, still little is known about the reason underlying the variability within lipid membranes, and its biochemical significance. In this review, we discuss the structural complexity of lipid membranes, as well as the importance to simplify studied systems in order to understand phenomena occurring in natural, complex membranes. Such systems require a model interface to be analyzed. Therefore, here we focused on analytical studies of artificial systems at various interfaces. The molecular structure of lipid membranes, specifically the nanometric thickens of molecular bilayer, limits in a major extent the choice of highly sensitive methods suitable to study such structures. Therefore, we focused on methods that combine high sensitivity, and/or chemical selectivity, and/or nanometric spatial resolution, such as atomic force microscopy, nanospectroscopy (tip-enhanced Raman spectroscopy, infrared nanospectroscopy), phase modulation infrared reflection-absorption spectroscopy, sum-frequency generation spectroscopy. We summarized experimental and theoretical approaches providing information about molecular structure and composition, lipid spatial distribution (phase separation), organization (domain shape, molecular orientation) of lipid membranes, and real-time visualization of the influence of various molecules (proteins, drugs) on their integrity. An integral part of this review discusses the latest achievements in the field of lipid layer-based biosensors.
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Narita T, Ariga K, Kunitake T, Oishi Y. Structural-Size Control of Domain from Nano to Micro: Logical Balancing between Attractive and Repulsive Interactions in Two Dimensions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10383-10389. [PMID: 31317749 DOI: 10.1021/acs.langmuir.9b01627] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Molecules aggregate to form a structure through various interactions involving dispersion force, electrostatic force, and so on. In two-dimensional systems, a surface energetic effect is further important for the molecular aggregation structure. We show that the domain size and its morphology in the mixed monomolecular film composed of hydrocarbon and fluorocarbon skeletons with different surface free energies extremely change depending on pH and NaCl concentration in the subphase. Such morphological changes can be interpreted by the balance of dipole density and line tension, which help in the development of an understanding of phase separation phenomena and provide a novel technique for structural control in two dimensions.
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Affiliation(s)
- Takayuki Narita
- Department of Chemistry and Applied Chemistry , Saga University , 1 Honjo , Saga 840-8502 , Japan
| | - Katsuhiko Ariga
- World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science (NIMS) , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
- Department of Advanced Materials Science, Graduate School of Frontier Sciences , The University of Tokyo , 5-1-5 Kashiwanoha , Kashiwa , Chiba 277-8561 , Japan
| | - Toyoki Kunitake
- Institute for Advanced Study , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka-shi , Fukuoka 819-0395 , Japan
| | - Yushi Oishi
- Department of Chemistry and Applied Chemistry , Saga University , 1 Honjo , Saga 840-8502 , Japan
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5
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Abstract
In this chapter, we briefly describe the structural features of gangliosides, and focus on the peculiar chemicophysical features of gangliosides, an important class of membrane amphipathic lipids that represent an important driving force determining the organization and properties of cellular membranes.
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Nasrallah H, Vial A, Pocholle N, Soulier J, Costa L, Godefroy C, Bourillot E, Lesniewska E, Milhiet PE. Imaging Artificial Membranes Using High-Speed Atomic Force Microscopy. Methods Mol Biol 2019; 1886:45-59. [PMID: 30374861 DOI: 10.1007/978-1-4939-8894-5_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Supported lipid bilayers represent a very attractive way to mimic biological membranes, especially to investigate molecular mechanisms associated with the lateral segregation of membrane components. Observation of these model membranes with high-speed atomic force microscopy (HS-AFM) allows the capture of both topography and dynamics of membrane components, with a spatial resolution in the nanometer range and image capture time of less than 1 s. In this context, we have developed new protocols adapted for HS-AFM to form supported lipid bilayers on small mica disks using the vesicle fusion or Langmuir-Blodgett methods. In this chapter we describe in detail the protocols to fabricate supported artificial bilayers as well as the main guidelines for HS-AFM imaging of such samples.
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Affiliation(s)
- Hussein Nasrallah
- INSERM, U1054, Montpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048, Montpellier, France
| | - Anthony Vial
- INSERM, U1054, Montpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048, Montpellier, France
| | - Nicolas Pocholle
- ICB UMR CNRS 6303, University of Bourgogne Franche-Comte, Dijon, France
| | - Jérémy Soulier
- INSERM, U1054, Montpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048, Montpellier, France
| | - Luca Costa
- INSERM, U1054, Montpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048, Montpellier, France
| | - Cédric Godefroy
- INSERM, U1054, Montpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048, Montpellier, France
| | - Eric Bourillot
- ICB UMR CNRS 6303, University of Bourgogne Franche-Comte, Dijon, France
| | - Eric Lesniewska
- ICB UMR CNRS 6303, University of Bourgogne Franche-Comte, Dijon, France
| | - Pierre-Emmanuel Milhiet
- INSERM, U1054, Montpellier, France.
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048, Montpellier, France.
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Colin J, Gregory-Pauron L, Lanhers MC, Claudepierre T, Corbier C, Yen FT, Malaplate-Armand C, Oster T. Membrane raft domains and remodeling in aging brain. Biochimie 2016; 130:178-187. [DOI: 10.1016/j.biochi.2016.08.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/31/2016] [Indexed: 12/21/2022]
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8
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The temperature-dependent physical state of polar lipids and their miscibility impact the topography and mechanical properties of bilayer models of the milk fat globule membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2181-2190. [DOI: 10.1016/j.bbamem.2016.06.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/19/2016] [Accepted: 06/22/2016] [Indexed: 11/23/2022]
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9
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Murthy AVR, Guyomarc'h F, Lopez C. Cholesterol Decreases the Size and the Mechanical Resistance to Rupture of Sphingomyelin Rich Domains, in Lipid Bilayers Studied as a Model of the Milk Fat Globule Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:6757-6765. [PMID: 27300157 DOI: 10.1021/acs.langmuir.6b01040] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Sphingomyelin-rich microdomains have been observed in the biological membrane surrounding milk fat globules (MFGM). The role played by cholesterol in these domains and in the physical properties and functions of the MFGM remains poorly understood. The objective of this work was therefore to investigate the phase state, topography, and mechanical properties of MFGM polar lipid bilayers as a function of cholesterol concentration, by combining X-ray diffraction, atomic force microscopy imaging, and force spectroscopy. At room temperature, i.e. below the phase transition temperature of the MFGM polar lipids, the bilayers showed the formation of sphingomyelin-rich domains in the solid ordered (so) phase that protruded about 1 nm above the liquid disordered (ld) phase. These so phase domains have a higher mechanical resistance to rupture than the ld phase (30 nN versus 15 nN). Addition of cholesterol in the MFGM polar lipid bilayers (i) induced the formation of liquid ordered (lo) phase for up to 27 mol % in the bilayers, (ii) decreased the height difference between the thicker ordered domains and the surrounding ld phase, (iii) promoted the formation of small sized domains, and (iv) decreased the mechanical resistance to rupture of the sphingomyelin-rich domains down to ∼5 nN. The biological and functional relevance of the lo phase cholesterol/sphingomyelin-rich domains in the membrane surrounding fat globules in milk remains to be elucidated. This study brought new insight about the functional role of cholesterol in milk polar lipid ingredients, which can be used in the preparation of food emulsions, e.g. infant milk formulas.
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Murthy AVR, Guyomarc'h F, Paboeuf G, Vié V, Lopez C. Cholesterol strongly affects the organization of lipid monolayers studied as models of the milk fat globule membrane: Condensing effect and change in the lipid domain morphology. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2308-16. [DOI: 10.1016/j.bbamem.2015.06.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 06/05/2015] [Accepted: 06/13/2015] [Indexed: 11/25/2022]
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11
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Cell-mimetic coatings for immune spheres. Colloids Surf B Biointerfaces 2014; 123:845-51. [PMID: 25454756 DOI: 10.1016/j.colsurfb.2014.10.029] [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: 04/07/2014] [Revised: 10/01/2014] [Accepted: 10/14/2014] [Indexed: 11/22/2022]
Abstract
Extrinsically induced or engineered cells are providing new therapeutic means in emerging fields such as cell therapeutics, immunomodulation and regenerative medicine. We are demonstrating a spatial induction method using lipid coatings, which can change signal presentation strength from material surface to adherent macrophage cells, that induce early cell-cell interaction leading to organotypic morphology. For that, we have developed a cell mimetic lipid coating with a rafts size to the order of transmembrane proteins (<10 nm) with enhanced lateral elastic properties. Such surface coatings are capable of reducing adherent macrophage spreading, while enabling early induction of cell-cell interaction to form organotypic macrophage colonies or "spheres" (M-spheres).
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12
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Guyomarc'h F, Zou S, Chen M, Milhiet PE, Godefroy C, Vié V, Lopez C. Milk sphingomyelin domains in biomimetic membranes and the role of cholesterol: morphology and nanomechanical properties investigated using AFM and force spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:6516-6524. [PMID: 24835749 DOI: 10.1021/la501640y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Milk sphingomyelin (MSM) and cholesterol segregate into domains in the outer bilayer membrane surrounding milk fat globules. To elucidate the morphology and mechanical properties of theses domains, supported lipid bilayers with controlled molar proportions of MSM, dioleoylphosphatidylcholine (DOPC) and cholesterol were produced in buffer mimicking conditions of the milk aqueous phase. Atomic force microscopy imaging showed that (i) for T < 35 °C MSM segregated in gel phase domains protruding above the fluid phase, (ii) the addition of 20 mol % cholesterol resulted in smaller and more elongated l(o) phase domains than in equimolar MSM/DOPC membranes, (iii) the MSM/cholesterol-enriched l(o) phase domains were less salient than the MSM gel phase domains. Force spectroscopy measurements furthermore showed that cholesterol reduced the resistance of MSM/DOPC membrane to perforation. The results are discussed with respect to the effect of cholesterol on the biophysical properties of lipid membranes. The combination of AFM imaging and force mapping provides unprecedented insight into the structural and mechanical properties of milk lipid membranes, and opens perspectives for investigation of the functional properties of MSM domains during milk fat processing or digestion.
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13
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Visualizing a multidrug resistance protein, EmrE, with major bacterial lipids using Brewster angle microscopy. Chem Phys Lipids 2013; 167-168:33-42. [DOI: 10.1016/j.chemphyslip.2013.01.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/22/2012] [Accepted: 01/18/2013] [Indexed: 11/17/2022]
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14
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Picas L, Milhiet PE, Hernández-Borrell J. Atomic force microscopy: a versatile tool to probe the physical and chemical properties of supported membranes at the nanoscale. Chem Phys Lipids 2012. [PMID: 23194897 DOI: 10.1016/j.chemphyslip.2012.10.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Atomic force microscopy (AFM) was developed in the 1980s following the invention of its precursor, scanning tunneling microscopy (STM), earlier in the decade. Several modes of operation have evolved, demonstrating the extreme versatility of this method for measuring the physicochemical properties of samples at the nanoscopic scale. AFM has proved an invaluable technique for visualizing the topographic characteristics of phospholipid monolayers and bilayers, such as roughness, height or laterally segregated domains. Implemented modes such as phase imaging have also provided criteria for discriminating the viscoelastic properties of different supported lipid bilayer (SLB) regions. In this review, we focus on the AFM force spectroscopy (FS) mode, which enables determination of the nanomechanical properties of membrane models. The interpretation of force curves is presented, together with newly emerging techniques that provide complementary information on physicochemical properties that may contribute to our understanding of the structure and function of biomembranes. Since AFM is an imaging technique, some basic indications on how real-time AFM imaging is evolving are also presented at the end of this paper.
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Affiliation(s)
- Laura Picas
- Institut Curie, CNRS UMR 144, 26 rue d'Ulm, 75248 Paris, France
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15
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Weeraman C, Chen M, Moffatt DJ, Lausten R, Stolow A, Johnston LJ. A combined vibrational sum frequency generation spectroscopy and atomic force microscopy study of sphingomyelin-cholesterol monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:12999-13007. [PMID: 22889131 DOI: 10.1021/la301332e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A combination of vibrational sum frequency generation spectroscopy and atomic force microscopy is used to study the changes in morphology and conformational order in monolayers prepared from three natural sphingomyelin (SM) mixtures as a function of surface pressure and cholesterol concentration. The most homogeneous SM gave monolayers with well-ordered acyl chains and few gauche defects with relatively small effects of either increasing surface pressure or cholesterol addition. Heterogeneous SM mixtures with a mixture of acyl chain lengths or with significant fractions of unsaturated acyl chains had much larger contributions from gauche defects at low surface pressure and gave increasingly well-ordered monolayers as the surface pressure increased. They also showed substantial increases in lipid chain order after cholesterol addition. Overall, these results are consistent with the strong hydrogen bonding capacity of SM leading to well-ordered monolayers over a range of surface pressures. The changes in acyl chain order for natural SMs as a function of cholesterol are relevant to formation of sphingolipid-cholesterol enriched domains in cell membranes.
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Affiliation(s)
- Champika Weeraman
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, ON, Canada
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16
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Cacas JL, Furt F, Le Guédard M, Schmitter JM, Buré C, Gerbeau-Pissot P, Moreau P, Bessoule JJ, Simon-Plas F, Mongrand S. Lipids of plant membrane rafts. Prog Lipid Res 2012; 51:272-99. [PMID: 22554527 DOI: 10.1016/j.plipres.2012.04.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipids tend to organize in mono or bilayer phases in a hydrophilic environment. While they have long been thought to be incapable of coherent lateral segregation, it is now clear that spontaneous assembly of these compounds can confer microdomain organization beyond spontaneous fluidity. Membrane raft microdomains have the ability to influence spatiotemporal organization of protein complexes, thereby allowing regulation of cellular processes. In this review, we aim at summarizing briefly: (i) the history of raft discovery in animals and plants, (ii) the main findings about structural and signalling plant lipids involved in raft segregation, (iii) imaging of plant membrane domains, and their biochemical purification through detergent-insoluble membranes, as well as the existing debate on the topic. We also discuss the potential involvement of rafts in the regulation of plant physiological processes, and further discuss the prospects of future research into plant membrane rafts.
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Affiliation(s)
- Jean-Luc Cacas
- Laboratoire de Biogenèse Membranaire, UMR 5200 CNRS, Université de Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France
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Sphingomyelin/phosphatidylcholine/cholesterol monolayers--analysis of the interactions in model membranes and Brewster Angle Microscopy experiments. Colloids Surf B Biointerfaces 2012; 93:174-9. [PMID: 22277747 DOI: 10.1016/j.colsurfb.2011.12.035] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Revised: 12/27/2011] [Accepted: 12/28/2011] [Indexed: 11/22/2022]
Abstract
In this work the properties of two ternary sphingomyelin/phosphatidylcholine/cholesterol monolayers imitating erythrocyte membrane were studied at various content of sterol. Phosphatidylcholines chosen for experiments differ in the length of sn-1 saturated chain in the molecule (1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine-SOPC vs. 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine - POPC). Langmuir monolayer experiments combined with Brewster Angle Microscopy prove that for both investigated systems the most favorable effect of cholesterol appears at 30% of sterol in the film. However, the interactions between molecules at 50% of sterol are only slightly weaker as compared to those for 1:1:1 films. It was also found that only at higher sterol concentration appear differences in the ordering effect of cholesterol on the systems containing PC molecules of various length of sn-1 saturated chain. Although the differences in the properties of POPC versus SOPC-containing monolayers were found, similarities in the morphology of the respective systems and stoichiometry of thermodynamically the most favorable mixture allow one to conclude that both SM/POPC/Chol as well as SM/SOPC/Chol monolayer can be used to mimic raft systems.
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18
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Puri A, Jang H, Yavlovich A, Masood MA, Veenstra TD, Luna C, Aranda-Espinoza H, Nussinov R, Blumenthal R. Material properties of matrix lipids determine the conformation and intermolecular reactivity of diacetylenic phosphatidylcholine in the lipid bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:15120-8. [PMID: 22053903 PMCID: PMC3237889 DOI: 10.1021/la203453x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Photopolymerizable phospholipid DC(8,9)PC (1,2-bis-(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine) exhibits unique assembly characteristics in the lipid bilayer. Because of the presence of the diacetylene groups, DC(8,9)PC undergoes polymerization upon UV (254 nm) exposure and assumes chromogenic properties. DC(8,9)PC photopolymerization in gel-phase matrix lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monitored by UV-vis absorption spectroscopy occurred within 2 min after UV treatment, whereas no spectral shifts were observed when DC(8,9)PC was incorporated into liquid-phase matrix 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Liquid chromatography-tandem mass spectrometry analysis showed a decrease in the amount of DC(8,9)PC monomer in both DPPC and POPC environments without any change in the matrix lipids in UV-treated samples. Molecular dynamics (MD) simulations of DPPC/DC(8,9)PC and POPC/DC(8,9)PC bilayers indicate that the DC(8,9)PC molecules adjust to the thickness of the matrix lipid bilayer. Furthermore, the motions of DC(8,9)PC in the gel-phase bilayer are more restricted than in the fluid bilayer. The restricted motional flexibility of DC(8,9)PC (in the gel phase) enables the reactive diacetylenes in individual molecules to align and undergo polymerization, whereas the unrestricted motions in the fluid bilayer restrict polymerization because of the lack of appropriate alignment of the DC(8,9)PC fatty acyl chains. Fluorescence microscopy data indicates the homogeneous distribution of lipid probe 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-lissamine rhodamine B sulfonyl ammonium salt (N-Rh-PE) in POPC/DC(8,9)PC monolayers but domain formation in DPPC/DC(8,9)PC monolayers. These results show that the DC(8,9)PC molecules cluster and assume the preferred conformation in the gel-phase matrix for the UV-triggered polymerization reaction.
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Affiliation(s)
- Anu Puri
- Membrane Structure and Function Section, SAIC-Frederick, Inc., Nanobiology Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Hyunbum Jang
- Basic Science Program, SAIC-Frederick, Inc., Nanobiology Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Amichai Yavlovich
- Membrane Structure and Function Section, SAIC-Frederick, Inc., Nanobiology Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - M. Athar Masood
- Laboratory of Proteomics and Analytical Technologies, Advanced Technology Program, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, MD 21702
| | - Timothy D. Veenstra
- Laboratory of Proteomics and Analytical Technologies, Advanced Technology Program, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, MD 21702
| | - Carlos Luna
- Fischell Department of Bioengineering, University of Maryland, College Park, MD
| | | | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick, Inc., Nanobiology Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Robert Blumenthal
- Membrane Structure and Function Section, SAIC-Frederick, Inc., Nanobiology Program, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
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19
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Fadel O, El Kirat K, Morandat S. The natural antioxidant rosmarinic acid spontaneously penetrates membranes to inhibit lipid peroxidation in situ. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1808:2973-80. [PMID: 21864504 DOI: 10.1016/j.bbamem.2011.08.011] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/26/2011] [Accepted: 08/04/2011] [Indexed: 01/12/2023]
Abstract
Exogenous molecules from dietary sources such as polyphenols are very efficient in preventing the alteration of lipid membranes by oxidative stress. Among the polyphenols, we have chosen to study rosmarinic acid (RA). We investigated the efficiency of RA in preventing lipid peroxidation and in interacting with lipids. We used liposomes of 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLPC) to show that RA was an efficient antioxidant. By HPLC, we determined that the maximum amount of RA associated with the lipids was ~1 mol%. Moreover, by using Langmuir monolayers, we evidenced that cholesterol decreases the penetration of RA. The investigation of transferred lipid/RA monolayers by atomic force microscopy revealed that 1 mol% of RA in the membrane was not sufficient to alter the membrane structure at the nanoscale. By fluorescence, we observed no significant modification of membrane permeability and fluidity caused by the interaction with RA. We also deduced that RA molecules were mainly located among the polar headgroups of the lipids. Finally, we prepared DLPC/RA vesicles to evidence for the first time that up to 1 mol% of RA inserts spontaneously in the membrane, which is high enough to fully prevent lipid peroxidation without any noticeable alteration of the membrane structure due to RA insertion.
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Affiliation(s)
- Ophélie Fadel
- Université de Technologie de Compiègne-CNRS, UMR 6022 Génie Enzymatique et Cellulaire, BP 20529, 60205 Compiègne Cedex, France
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20
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Seantier B, Dezi M, Gubellini F, Berquand A, Godefroy C, Dosset P, Lévy D, Milhiet PE. Transfer on hydrophobic substrates and AFM imaging of membrane proteins reconstituted in planar lipid bilayers. J Mol Recognit 2011; 24:461-6. [DOI: 10.1002/jmr.1070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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21
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Ethanol effects on binary and ternary supported lipid bilayers with gel/fluid domains and lipid rafts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:405-14. [DOI: 10.1016/j.bbamem.2010.10.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 10/08/2010] [Accepted: 10/12/2010] [Indexed: 12/19/2022]
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22
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Gallier S, Gragson D, Jiménez-Flores R, Everett DW. Surface characterization of bovine milk phospholipid monolayers by Langmuir isotherms and microscopic techniques. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:12275-12285. [PMID: 21067228 PMCID: PMC4392927 DOI: 10.1021/jf102185a] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Monolayers were prepared from phospholipids extracted from bovine milk and used as a model system to mimic the native milk fat globule membrane (MFGM) surface structure in various microscopic experiments. The natural complex mixtures of phospholipids were isolated from bovine raw milk, raw cream, processed whole milk, and buttermilk powder by total lipid extraction and solid-phase extraction. A Langmuir film balance mounted on an epifluorescence microscope was used to analyze the physical behavior of the monolayer films and the phase coexistence resulting from the formation of phospholipid microdomains within these films. Atomic force microscopy was used for nanometer-scale topographic resolution of the microdomains. This study allowed comparison of the behavior of phospholipid monolayers from dairy products at different stages of processing, analysis of the formation of microdomains, and the study of the effect of milk processing on lipid-lipid interactions and phase coexistence. It was observed that milk processing changes the physical behavior of phospholipid monolayers by altering the phospholipid profile and the fatty acid distribution.
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Affiliation(s)
- Sophie Gallier
- Department of Food Science, University of Otago, Dunedin, New Zealand
- Dairy Products Technology Center, California Polytechnic State University, San Luis Obispo, California, USA
| | - Derek Gragson
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California, USA
| | - Rafael Jiménez-Flores
- Dairy Products Technology Center, California Polytechnic State University, San Luis Obispo, California, USA
| | - David W. Everett
- Department of Food Science, University of Otago, Dunedin, New Zealand
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23
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Oguchi T, Sakai K, Sakai H, Abe M. AFM surface morphology and friction force studies of microscale domain structures of binary phospholipids. Colloids Surf B Biointerfaces 2010; 79:205-9. [DOI: 10.1016/j.colsurfb.2010.03.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Accepted: 03/31/2010] [Indexed: 11/25/2022]
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24
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Giocondi MC, Yamamoto D, Lesniewska E, Milhiet PE, Ando T, Le Grimellec C. Surface topography of membrane domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:703-18. [DOI: 10.1016/j.bbamem.2009.09.015] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 09/11/2009] [Accepted: 09/20/2009] [Indexed: 12/24/2022]
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25
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Azouzi S, El Kirat K, Morandat S. The potent antimalarial drug cyclosporin A preferentially destabilizes sphingomyelin-rich membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:1960-1965. [PMID: 19697916 DOI: 10.1021/la902580w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cyclosporin A (CsA) is a hydrophobic cyclic peptide produced by a fungus. CsA is widely used as an immunosuppressive agent to inhibit the rejection of transplanted organs. CsA also exhibits an antiparasitic activity against Plasmodium, the microorganism responsible for malaria disease. This antimalarial activity is not completely understood yet. In this study, we have used Langmuir monolayers and atomic force microscopy to investigate the interaction of CsA with different lipids: phosphatidylcholines with different molecular packing, cholesterol, and sphingomyelin. We have shown that CsA inserts in all kinds of lipid monolayers but it has a marked preference for sphingomyelin monolayers. This preferential insertion of CsA within sphingomyelin-enriched membranes could explain the antimalarial activity of CsA. Indeed, the parasites need to produce a membrane network inside the erythrocytes, which allows for their proper development/multiplication by exchanging nutrients with the external medium. This membrane network is particularly enriched in sphingomyelin, so the preferential insertion of CsA in these bilayers may destabilize them, thereby inhibiting the development of the parasite.
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Affiliation(s)
- Slim Azouzi
- Laboratoire de Génie Enzymatique et Cellulaire, CNRS UMR 6022, 60205 Compiègne Cedex, France
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26
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Albino JD, Nambi IM. Effect of biosurfactants on the aqueous solubility of PCE and TCE. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2009; 44:1565-1573. [PMID: 20183515 DOI: 10.1080/10934520903263538] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The effect of biosurfactants on the solubility of tetrachloroethylene (PCE) and trichloroethylene (TCE) was studied in batch experiments pertaining to their use for solubilization and mobilization of such contaminants in surfactant enhanced aquifer remediation. Biosurfactants, rhamnolipid and surfactin used in solubility studies were synthesized in our laboratory by Pseudomonas aeruginosa (MTCC 2297) and Bacillus subtilis (MTCC 2423), respectively. The efficiency of the biosurfactants in solubilizing the chlorinated solvents was compared to that of synthetic surfactants. The Weight Solubilization Ratio (WSR) values for solubilization of PCE and TCE by biosurfactants were very high compared to the values obtained for synthetic surfactants. Surfactin proved to be a better surfactant over rhamnolipid. The WSR of surfactin on solubilization of PCE and TCE were 3.83 and 12.5, respectively, whereas the values obtained for rhamnolipid were 2.06 and 8.36. The solubility of the chlorinated solvents by biosurfactants was considerably affected by the changes in pH. The aqueous solubility of PCE and TCE increased tremendously with decrease in pH. The solubility of biosurfactants was observed to decrease with the pH, favoring partitioning of surfactants into the chlorinated solvents in significant amounts at lower pH. The excessive accumulation of biosurfactants at the interface facilitated interfacial tension reductions resulting in higher solubility of the chlorinated solvents at pH less than 7.
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Affiliation(s)
- John D Albino
- Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India
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27
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Panda AK, Wojciechowski P, Nag K, Possmayer F, Petersen NO. Thermodynamic and Fluorescence Studies on the Interaction of Cholesterol with Palmitoyl-Oleoyl Phosphatidylcholine and Sphingomyelin. J DISPER SCI TECHNOL 2009. [DOI: 10.1080/01932690902735124] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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28
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Picas L, Montero MT, Morros A, Cabañas ME, Seantier B, Milhiet PE, Hernández-Borrell J. Calcium-Induced Formation of Subdomains in Phosphatidylethanolamine−Phosphatidylglycerol Bilayers: A Combined DSC, 31P NMR, and AFM Study. J Phys Chem B 2009; 113:4648-55. [DOI: 10.1021/jp8102468] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laura Picas
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona (UB), and Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), E-08028 Barcelona, Spain, Unitat de Biofísica, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Centre d’Estudis en Biofísica (CEB), and Servei de Ressonància Magnètica Nuclear (SeRMN), UAB, E-08193 Bellaterra, Barcelona, Spain, and Inserm, Unité 554, Montpellier, France, and Centre de Biochimie Structurale, Université
| | - M. Teresa Montero
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona (UB), and Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), E-08028 Barcelona, Spain, Unitat de Biofísica, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Centre d’Estudis en Biofísica (CEB), and Servei de Ressonància Magnètica Nuclear (SeRMN), UAB, E-08193 Bellaterra, Barcelona, Spain, and Inserm, Unité 554, Montpellier, France, and Centre de Biochimie Structurale, Université
| | - Antoni Morros
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona (UB), and Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), E-08028 Barcelona, Spain, Unitat de Biofísica, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Centre d’Estudis en Biofísica (CEB), and Servei de Ressonància Magnètica Nuclear (SeRMN), UAB, E-08193 Bellaterra, Barcelona, Spain, and Inserm, Unité 554, Montpellier, France, and Centre de Biochimie Structurale, Université
| | - Miquel E. Cabañas
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona (UB), and Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), E-08028 Barcelona, Spain, Unitat de Biofísica, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Centre d’Estudis en Biofísica (CEB), and Servei de Ressonància Magnètica Nuclear (SeRMN), UAB, E-08193 Bellaterra, Barcelona, Spain, and Inserm, Unité 554, Montpellier, France, and Centre de Biochimie Structurale, Université
| | - Bastien Seantier
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona (UB), and Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), E-08028 Barcelona, Spain, Unitat de Biofísica, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Centre d’Estudis en Biofísica (CEB), and Servei de Ressonància Magnètica Nuclear (SeRMN), UAB, E-08193 Bellaterra, Barcelona, Spain, and Inserm, Unité 554, Montpellier, France, and Centre de Biochimie Structurale, Université
| | - Pierre-Emmanuel Milhiet
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona (UB), and Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), E-08028 Barcelona, Spain, Unitat de Biofísica, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Centre d’Estudis en Biofísica (CEB), and Servei de Ressonància Magnètica Nuclear (SeRMN), UAB, E-08193 Bellaterra, Barcelona, Spain, and Inserm, Unité 554, Montpellier, France, and Centre de Biochimie Structurale, Université
| | - Jordi Hernández-Borrell
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona (UB), and Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), E-08028 Barcelona, Spain, Unitat de Biofísica, Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Centre d’Estudis en Biofísica (CEB), and Servei de Ressonància Magnètica Nuclear (SeRMN), UAB, E-08193 Bellaterra, Barcelona, Spain, and Inserm, Unité 554, Montpellier, France, and Centre de Biochimie Structurale, Université
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29
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Fluorescence correlation spectroscopy in membrane structure elucidation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:225-33. [DOI: 10.1016/j.bbamem.2008.08.013] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 08/12/2008] [Accepted: 08/21/2008] [Indexed: 11/18/2022]
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30
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Popov J, Vobornik D, Coban O, Keating E, Miller D, Francis J, Petersen NO, Johnston LJ. Chemical mapping of ceramide distribution in sphingomyelin-rich domains in monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13502-13508. [PMID: 18973350 DOI: 10.1021/la8007552] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The incorporation of ceramide in phase-separated monolayers of ternary lipid mixtures has been studied by a combination of atomic force microscopy (AFM), fluorescence, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Replacement of a fraction of the sphingomyelin by ceramide in DOPC/SM/cholesterol monolayers leads to changes in the SM-cholesterol-rich liquid-ordered domains. AFM shows the formation of heterogeneous domains with small raised islands that are assigned to a ceramide-rich gel phase. ToF-SIMS provides conclusive evidence for the localization of SM and ceramide in ordered domains and shows that ceramide is heterogeneously distributed in small islands throughout the domains. The results indicate the utility of combining AFM and ToF-SIMS for understanding compositions of phase-separated membranes.
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Affiliation(s)
- Jesse Popov
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada
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31
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Sesana S, Re F, Bulbarelli A, Salerno D, Cazzaniga E, Masserini M. Membrane Features and Activity of GPI-Anchored Enzymes: Alkaline Phosphatase Reconstituted in Model Membranes. Biochemistry 2008; 47:5433-40. [DOI: 10.1021/bi800005s] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Silvia Sesana
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
| | - Francesca Re
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
| | | | - Domenico Salerno
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
| | - Emanuela Cazzaniga
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
| | - Massimo Masserini
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
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32
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Lorin A, Charloteaux B, Fridmann-Sirkis Y, Thomas A, Shai Y, Brasseur R. Mode of Membrane Interaction and Fusogenic Properties of a de Novo Transmembrane Model Peptide Depend on the Length of the Hydrophobic Core. J Biol Chem 2007; 282:18388-18396. [PMID: 17459883 DOI: 10.1074/jbc.m700099200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Model peptides composed of alanine and leucine residues are often used to mimic single helical transmembrane domains. Many studies have been carried out to determine how they interact with membranes. However, few studies have investigated their lipid-destabilizing effect. We designed three peptides designated KALRs containing a hydrophobic stretch of 14, 18, or 22 alanines/leucines surrounded by charged amino acids. Molecular modeling simulations in an implicit membrane model as well as attenuated total reflection-Fourier transform infrared analyses show that KALR is a good model of a transmembrane helix. However, tryptophan fluorescence and attenuated total reflection-Fourier transform infrared spectroscopy indicate that the extent of binding and insertion into lipids increases with the length of the peptide hydrophobic core. Although binding can be directly correlated to peptide hydrophobicity, we show that insertion of peptides into a membrane is determined by the length of the peptide hydrophobic core. Functional studies were performed by measuring the ability of peptides to induce lipid mixing and leakage of liposomes. The data reveal that whereas KALR14 does not destabilize liposomal membranes, KALR18 and KALR22 induce 40 and 50% of lipid-mixing, and 65 and 80% of leakage, respectively. These results indicate that a transmembrane model peptide can induce liposome fusion in vitro if it is long enough. The reasons for the link between length and fusogenicity are discussed in relation to studies of transmembrane domains of viral fusion proteins. We propose that fusogenicity depends not only on peptide insertion but also on the ability of peptides to destabilize the two leaflets of the liposome membrane.
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Affiliation(s)
- Aurélien Lorin
- Gembloux Agricultural University, Centre de Biophysique Moléculaire Numérique, B-5030 Gembloux, Belgium
| | - Benoit Charloteaux
- Gembloux Agricultural University, Centre de Biophysique Moléculaire Numérique, B-5030 Gembloux, Belgium
| | - Yael Fridmann-Sirkis
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Annick Thomas
- Gembloux Agricultural University, Centre de Biophysique Moléculaire Numérique, B-5030 Gembloux, Belgium
| | - Yechiel Shai
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Robert Brasseur
- Gembloux Agricultural University, Centre de Biophysique Moléculaire Numérique, B-5030 Gembloux, Belgium.
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33
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Johnston LJ. Nanoscale imaging of domains in supported lipid membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:5886-95. [PMID: 17428076 DOI: 10.1021/la070108t] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The formation of domains in supported lipid membranes has been studied extensively as a model for the 2D organization of cell membranes. The compartmentalization of biological membranes to give domains such as cholesterol-rich rafts plays an important role in many biological processes. This article summarizes experiments from the author's laboratory in which a combination of atomic force microscopy and near-field scanning optical microscopy is used to probe phase separation in supported monolayers and bilayers as models for membrane rafts. These techniques are used to study binary and ternary lipid mixtures that have gel-phase or liquid-ordered domains that vary in size from tens of nanometers to tens of micrometers, surrounded by a fluid-disordered membrane. Examples are presented in which these models are used to investigate the distribution of glycolipid membrane raft markers and the preference for peptide and protein localization in ordered versus fluid membrane phases. Finally, the enzyme-mediated restructuring of membranes containing liquid-ordered domains provides an in vitro model for the coalescence of membrane rafts to give signaling platforms. Overall, the results demonstrate the importance of using techniques that can probe the nanoscale organization of membranes and of combining techniques that yield complementary information. Furthermore, the ability of supported lipid bilayers to model some aspects of membrane compartmentalization provides an important approach to understanding natural membranes.
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Affiliation(s)
- Linda J Johnston
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada.
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34
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Domènech O, Redondo L, Montero MT, Hernandez-Borrell J. Specific adsorption of cytochrome C on cardiolipin-glycerophospholipid monolayers and bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:5651-6. [PMID: 17419653 DOI: 10.1021/la0634241] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this study, we examined the adsorption of cytochrome c (cyt c) on monolayers and liposomes formed from (i) pure 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), or cardiolipin (CL) and on (ii) the more thermodynamically stable binary mixtures of POPE/CL (0.8:0.2 mol/mol) and POPC/CL (0.6:0.4 mol/mol). Constant surface pressure experiments showed that the maximum and minimum interactions occurred in the pure CL (anionic phospholipid) and the pure POPE (zwitterion) monolayers, respectively. Observation by atomic force microscopy (AFM) of the images of Langmuir-Blodgett (LB) films extracted at 30 mN m-1 suggests that the different interactions of cyt c with POPE/CL and the POPC/CL monolayers could be due to lateral phase separation occurring in the POPE/CL mixture. The competition between 8-anilino-1-naphthalene sulfonate (ANS) and cyt c for the same binding sites in liposomes that have identical nominal compositions with respect to those of the monolayers was used to obtain binding parameters. In agreement with the monolayer experiments, the most binding was observed in POPE/CL liposomes. All of our observations strongly support the existence of selective adsorption of cyt c on CL, which is modulated differently by different neutral phospholipids (POPE and POPC).
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Affiliation(s)
- Oscar Domènech
- Departament de Química-Física, Facultat de Química, and Departament de Fisicoquímica, Facultat de Farmacia, Universitat de Barcelona, Barcelona 08028, Spain
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35
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Garcia-Manyes S, Domènech O, Sanz F, Montero MT, Hernandez-Borrell J. Atomic force microscopy and force spectroscopy study of Langmuir–Blodgett films formed by heteroacid phospholipids of biological interest. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1190-8. [PMID: 17376401 DOI: 10.1016/j.bbamem.2007.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 01/17/2007] [Accepted: 02/01/2007] [Indexed: 01/19/2023]
Abstract
Langmuir-Blodgett (LB) films of two heteroacid phospholipids of biological interest 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), as well as a mixed monolayer with chi(POPC)=0.4, were transferred onto mica in order to investigate by a combination of atomic force microscopy (AFM) and force spectroscopy (FS) their height, and particularly, their nanomechanical properties. AFM images of such monolayers extracted at 30 mN m(-1) revealed a smooth and defect-free topography except for the POPE monolayer. Since scratching such soft monolayers in contact mode was proved unsuccessful, their molecular height was measured by means of the width of the jump present in the respective force-extension curves. While for pure POPC a small jump occurs near zero force, for the mixed monolayer with chi(POPC)=0.4 the jump occurs at approximately 800 pN. Widths of approximately 2 nm could be established for POPC and chi(POPC)=0.4, but not for POPE monolayer at this extracting pressure. Such different mechanical stability allowed us to directly measure the threshold area/lipid range value needed to induce mechanical stability to the monolayers. AFM imaging and FS were next applied to get further structural and mechanical insight into the POPE phase transition (LC-LC') occurring at pressures >36.5 mN m(-1). This phase transition was intimately related to a sudden decrease in the area/molecule value, resulting in a jump in the force curve occurring at high force ( approximately 1.72 nN). FS reveals to be the unique experimental technique able to unveil structural and nanomechanical properties for such soft phospholipid monolayers. The biological implications of the nanomechanical properties of the systems under investigation are discussed considering that the annular phospholipids region of some transmembrane proteins is enriched in POPE.
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Affiliation(s)
- Sergi Garcia-Manyes
- Departament de Química Física, Facultat de Química, Universitat de Barcelona, E-08028-Barcelona, Spain
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36
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Prenner E, Honsek G, Hönig D, Möbius D, Lohner K. Imaging of the domain organization in sphingomyelin and phosphatidylcholine monolayers. Chem Phys Lipids 2007; 145:106-18. [PMID: 17188673 DOI: 10.1016/j.chemphyslip.2006.11.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 11/03/2006] [Accepted: 11/13/2006] [Indexed: 11/26/2022]
Abstract
The lateral organization of biomembranes has gained significant interest when the fluid mosaic model was challenged by the model of "lipid rafts". Several lipid classes like cholesterol and sphingolipids are considered to be essential for their formation. Here we investigate the lateral domain formation in binary mixtures of sphingomyelin and phosphatidylcholine. Both are major lipid components of lipoproteins and mammalian cell membranes at various molar ratios. Surface pressure-area isotherms and surface potential-area isotherms of monolayers composed of these lipids clearly indicated non-ideal mixing. In addition, Brewster angle microscopy provided a well-suited approach to image the formation of lateral domains. These images demonstrated that pure sphingomyelin forms very stable finger-like domains that exhibit a distinct internal organization suggesting an anisotropic orientation of the acyl side chains. Similar behavior was found for mixtures containing more than 60 mol% sphingomyelin. With increasing content of phosphatidylcholine the domain size decreased and the surface pressure, where domain formation occurred, increased. At lower sphingomyelin content (30-60 mol%) rather round-shaped, smaller domains were observed. Thus, the potential of sphingomyelin domains as potentially important building blocks for actual domains that could be building blocks for raft formation is suggested, even without the presence of cholesterol. In addition, these observations may suggest a role for the distinct molar ratio of these key lipids frequently found in physiologically relevant particles such as low and high density lipoproteins or the outer leaflet of the human erythrocyte membrane.
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Affiliation(s)
- Elmar Prenner
- Department of Biological Sciences, 2500 University Drive, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
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37
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Coban O, Popov J, Burger M, Vobornik D, Johnston LJ. Transition from nanodomains to microdomains induced by exposure of lipid monolayers to air. Biophys J 2007; 92:2842-53. [PMID: 17237193 PMCID: PMC1831686 DOI: 10.1529/biophysj.106.088419] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The morphology of monolayers prepared from ternary lipid mixtures that have coexisting fluid phases has been examined by atomic force microscopy for samples transferred to mica before and after exposure to air. Mixtures of 1,2-dioleoyl-sn-glycero-3-phosphocholine and cholesterol with either egg sphingomyelin or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine were studied at several surface pressures. Both lipid mixtures have a combination of small islands and large microdomains at low surface pressure (5-10 mN/m) for monolayers deposited in either air or nitrogen. By contrast, monolayers have small interconnected nanodomains when deposited under nitrogen at 30 mN/m but mixtures of large microdomains and small nanodomains when transferred after exposure to air. These results are consistent with an earlier report that concluded that the formation of large domains at high surface pressures (>30 mN/m) for monolayers exposed to air is caused by lipid oxidation. However, the higher spatial resolution available with atomic force microscopy indicates that exposure of the monolayers to air leads to an increase in the size of preexisting nanodomains, rather than a change in the miscibility pressure. Examination of changes in surface morphology as a function of surface pressure demonstrate a gradual evolution in size and surface coverage for both nano- and microdomains, before formation of a network of interconnected nanodomains. Similar studies for binary mixtures in the absence of cholesterol indicate that lipid oxidation results in analogous changes in domain size for monolayers with coexisting gel and fluid phases. These results illustrate the importance of using techniques capable of probing the nanoscale organization of membranes.
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Affiliation(s)
- Oana Coban
- Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, Canada K1A OR6
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Ramstedt B, Slotte JP. Sphingolipids and the formation of sterol-enriched ordered membrane domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1945-56. [PMID: 16901461 DOI: 10.1016/j.bbamem.2006.05.020] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 05/18/2006] [Accepted: 05/24/2006] [Indexed: 12/18/2022]
Abstract
This review is focused on the formation of lateral domains in model bilayer membranes, with an emphasis on sphingolipids and their interaction with cholesterol. Sphingolipids in general show a preference for partitioning into ordered domains. One of the roles of cholesterol is apparently to modulate the fluidity of the sphingolipid domains and also to help segregate the domains for functional purposes. Cholesterol shows a preference for sphingomyelin over phosphatidylcholine with corresponding acyl chains. The interaction of cholesterol with different sphingolipids is largely dependent on the molecular properties of the particular sphingolipid in question. Small head group size clearly has a destabilizing effect on sphingolipid/cholesterol interaction, as exemplified by studies with ceramide and ceramide phosphoethanolamine. Ceramides actually displace sterol from ordered domains formed with saturated phosphatidylcholine or sphingomyelin. The N-linked acyl chain is known to be an important stabilizer of the sphingolipid/cholesterol interaction. However, N-acyl phosphatidylethanolamines failed to interact favorably with cholesterol and to form cholesterol-enriched lateral domains in bilayer membranes. Glycosphingolipids also form ordered domains in membranes but do not show a strong preference for interacting with cholesterol. It is clear from the studies reviewed here that small changes in the structure of sphingolipids alter their partitioning between lateral domains substantially.
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Affiliation(s)
- Bodil Ramstedt
- Department of Biochemistry and Pharmacy, Abo Akademi University, Tykistokatu 6A, 20520 Turku, Finland
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Windschiegl B, Steinem C. Influence of alpha-hydroxylation of glycolipids on domain formation in lipid monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:7454-7. [PMID: 16922519 DOI: 10.1021/la060146x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
By means of fluorescence and scanning force microscopy (SFM), we investigated the phase behavior of lipid monolayers composed of a mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, sphingomyelin, and cholesterol (5/2/3) with either alpha-hydroxylated or nonhydroxylated galactocerebroside. Fluorescence images of lipid monolayers at the air-water interface demonstrate that, independent of the lipid mixture, phase separation occurs at low surface pressure up to 4-6 mN m(-1), while an almost homogeneous phase is observed at larger surface pressures. However, by means of SFM of lipid monolayers transferred by the Langmuir-Blodgett technique at around 30 mN m(-1), nanometer-sized domains became discernible in those lipid mixtures that contained galactocerebroside, while, in that without a glycolipid, no such domain formation was visible. Moreover, the alpha-hydroxy group of the galactocerebroside alters the size and the total area of the domains significantly.
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Affiliation(s)
- Barbara Windschiegl
- Institut für Analytische Chemie, Chemo- und Biosensorik, Universität Regensburg, 93040 Regensburg, Germany
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40
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Sonnino S, Prinetti A, Mauri L, Chigorno V, Tettamanti G. Dynamic and Structural Properties of Sphingolipids as Driving Forces for the Formation of Membrane Domains. Chem Rev 2006; 106:2111-25. [PMID: 16771445 DOI: 10.1021/cr0100446] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sandro Sonnino
- Center of Excellence on Neurodegenerative Diseases, Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, 20090 Segrate (MI), Italy.
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41
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Connell SD, Smith DA. The atomic force microscope as a tool for studying phase separation in lipid membranes. Mol Membr Biol 2006; 23:17-28. [PMID: 16600898 DOI: 10.1080/09687860500501158] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Atomic force microscopy has developed into a powerful tool in the study of phase separation in lipid bilayers. Its ability to image a semi-fluid surface under buffer at nanometre lateral resolution and Angstrom resolution vertically allows us to distinguish phase separated lipid domains, models of the elusive rafts postulated to exist as functional platforms in the cellular membrane, which may only rise 0.3 nm above the surrounding membrane. This review charts the history of this development, and includes a description of sample preparation techniques, factors affecting image contrast mechanisms, its use in the investigation of the pre-transition ripple phase, and in the localization of cell surface proteins.
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Affiliation(s)
- Simon D Connell
- Astbury Centre for Structural Molecular Biology and School of Physics and Astronomy, University of Leeds, UK
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Nicolini C, Baranski J, Schlummer S, Palomo J, Lumbierres-Burgues M, Kahms M, Kuhlmann J, Sanchez S, Gratton E, Waldmann H, Winter R. Visualizing association of N-ras in lipid microdomains: influence of domain structure and interfacial adsorption. J Am Chem Soc 2006; 128:192-201. [PMID: 16390147 DOI: 10.1021/ja055779x] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, two-photon fluorescence microscopy on giant unilamellar vesicles and tapping-mode atomic force microscopy (AFM) are applied to follow the insertion of a fluorescently (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene, BODIPY) labeled and completely lipidated (hexadecylated and farnesylated) N-Ras protein into heterogeneous lipid bilayer systems. The bilayers consist of the canonical raft mixture 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), sphingomyelin, and cholesterol, which-depending on the concentration of the constituents-separates into liquid-disordered (l(d)), liquid-ordered (l(o)), and solid-ordered (s(o)) phases. The results provide direct evidence that partitioning of N-Ras occurs preferentially into liquid-disordered lipid domains, which is also reflected in a faster kinetics of incorporation into the fluid lipid bilayers. The phase sequence of preferential binding of N-Ras to mixed-domain lipid vesicles is l(d) > l(o) >> s(o). Intriguingly, we detect, using the better spatial resolution of AFM, also a large proportion of the lipidated protein located at the l(d)/l(o) phase boundary, thus leading to a favorable decrease in line tension that is associated with the rim of the demixed phases. Such an interfacial adsorption effect may serve as an alternative vehicle for association processes of signaling proteins in membranes.
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Affiliation(s)
- Chiara Nicolini
- Physical Chemistry I-Biophysical Chemistry and Organic Chemistry, Department of Chemistry, University of Dortmund, Otto-Hahn-Strasse 6, D-44227 Dortmund, Germany
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43
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Berring EE, Borrenpohl K, Fliesler SJ, Serfis AB. A comparison of the behavior of cholesterol and selected derivatives in mixed sterol-phospholipid Langmuir monolayers: a fluorescence microscopy study. Chem Phys Lipids 2005; 136:1-12. [PMID: 15904906 DOI: 10.1016/j.chemphyslip.2005.03.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 03/08/2005] [Accepted: 03/16/2005] [Indexed: 10/25/2022]
Abstract
Eukaryotic cells require sterols to achieve normal structure and function of their plasma membranes, and deviations from normal sterol composition can perturb these features and compromise cellular and organism viability. The Smith-Lemli-Opitz syndrome (SLOS) is a hereditary metabolic disease involving cholesterol (CHOL) deficiency and abnormal accumulation of the CHOL precursor, 7-dehydrocholesterol (7DHC). In this study, the interactions of CHOL and the related sterols desmosterol (DES) and 7DHC with l-alpha-dipalmitoylphosphatidylcholine (DPPC) monolayers were compared. Pressure-area isotherms and fluorescence microscopy were used to study DPPC monolayers containing 0, 10, 20, or 30 mol% sterol. Similar behavior was noted for CHOL- and DES-containing DPPC monolayers with both techniques. However, while 7DHC gave isotherms similar to those obtained with the other sterols, microscopy indicated limited domain formation with DPPC, indicating that 7DHC packs somewhat differently in DPPC membranes compared to CHOL and DES. These results are discussed in relation to SLOS pathobiology.
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Affiliation(s)
- Erin E Berring
- Department of Chemistry, Saint Louis University, Monsanto Hall 125, 3501 Laclede Avenue, St. Louis, MO 63103-2010, USA
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Mardilovich A, Kokkoli E. Patterned biomimetic membranes: effect of concentration and pH. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:7468-75. [PMID: 16042481 DOI: 10.1021/la0468085] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Planar-supported lipid bilayers have attracted enormous attention because of their properties as model cell membranes, which can be employed in a variety of fundamental biological studies and medical devices. Furthermore, the development of patterned biological interfaces is of great practical and scientific interest because of their potential applications in the field of biosensors, drug screening, tissue engineering, and medical implants. In this study, mica-supported membranes were constructed from biomimetic peptide-amphiphiles and their mixtures with lipidated poly(ethylene glycol) (PEG120) molecules or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) phospholipids using the Langmuir-Blodgett technique. The two peptide-amphiphiles used in this study were a fibronectin-mimetic with the PHSRN(SG)(3)SGRGDSP headgroup (referred to as PHSRN-GRGDSP) that contains both the primary (GRGDSP) and the synergy (PHSRN) recognition sites for alpha(5)beta(1) integrins and a peptide-amphiphile that mimics a fragment of the N-terminus of the fractalkine receptor (referred to as NTFR). Compression isotherms of the peptide-amphiphiles and their mixtures with PEG120 at the air/water interface were recorded and analyzed to evaluate the extent of miscibility in the two-component LB films. Domain formation in mica-supported bilayers constructed from mixtures of peptide-amphiphiles and lipidated PEG120 or DPPC was observed using atomic force microscopy. In PHSRN-GRGDSP/PEG120 mixtures deposited from an aqueous subphase at pH 7, concentration-dependent phase separation was observed on the AFM images. The NTFR/PEG120 and NTFR/DPPC mixtures deposited at pH 10 exhibited extensive lateral phase separation at all mixture compositions, whereas at deposition pH 7 the concentrations of NTFR/DPPC examined here were well mixed.
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Affiliation(s)
- Anastasia Mardilovich
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Chiantia S, Kahya N, Schwille P. Dehydration damage of domain-exhibiting supported bilayers: an AFM study on the protective effects of disaccharides and other stabilizing substances. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:6317-23. [PMID: 15982037 DOI: 10.1021/la050115m] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Atomic force microscopy (AFM) has been applied to characterize hydrated sphingomyelin/dioleoylphosphatidylcholine/cholesterol supported bilayers, after dehydration either in the absence or in the presence of several stabilizing substances. Such a study provides information about the effect of extreme environmental conditions on biological membranes and, in particular, on lipidic microdomains. Dehydration stress, indeed, is thought to cause both macroscopical damage and alterations of microdomains in biomembranes, leading to deleterious effects. These phenomena can be avoided if disaccharides are added during dehydration. In this work, we apply AFM imaging to directly visualize damage caused to supported lipid bilayers by water removal. We compare the efficiency of sucrose, trehalose, dextran, dimethyl sulfoxide, and glucose in preserving the structural integrity of domain-exhibiting model membranes. Finally, in addition to confirming previous findings, our results provide further insight into damage and alteration of microdomains in membranes as a consequence of stressful drying conditions.
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Affiliation(s)
- Salvatore Chiantia
- Biotechnologisches Zentrum, Dresden University of Technology, Tatzberg 47-51, D-01307, Dresden, Germany
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Eeman M, Deleu M, Paquot M, Thonart P, Dufrêne YF. Nanoscale properties of mixed fengycin/ceramide monolayers explored using atomic force microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:2505-2511. [PMID: 15752046 DOI: 10.1021/la0475775] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To gain insight into the interactions between fengycin and skin membrane lipids, mixed fengycin/ceramide monolayers were investigated using atomic force microscopy (AFM) (monolayers supported on mica) and surface pressure-area isotherms (monolayers at the air-water interface). AFM topographic images revealed phase separation in mixed monolayers prepared at 20 degrees C/pH 2 and composed of 0.25 and 0.5 fengycin molar ratios, in the form of two-dimensional (2-D) hexagonal crystalline domains of ceramide surrounded by a fengycin-enriched fluid phase. Surface pressure-area isotherms as well as friction and adhesion AFM images confirmed that the two phases had different molecular orientations: while ceramide formed a highly ordered phase with crystalline chain packing, fengycin exhibited a disordered fluid phase with the peptide ring lying horizontally on the substrate. Increasing the temperature and pH to values corresponding to the skin parameters, i.e., 37 degrees C/pH 5, was found to dramatically affect the film organization. At low fengycin molar ratio (0.25), the hexagonal ceramide domains transformed into round domains, while at higher ratio (0.5) these were shown to melt into a continuous fengycin/ceramide fluid phase. These observations were directly supported by the thermodynamic analysis (deviation from the additivity rule, excess of free energy) of the monolayer properties at the air-water interface. Accordingly, this study demonstrates that both the environmental conditions (temperature, pH) and fengycin concentration influence the molecular organization of mixed fengycin/ceramide monolayers. We believe that the ability to modulate the formation of 2-D domains in the skin membrane may be an important biological function of fengycin, which should be increasingly investigated in future pharmacological research.
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Affiliation(s)
- M Eeman
- Unité de Chimie Biologique Industrielle and Unité de Bio-industries, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés, 2, B-5030 Gembloux, Belgium
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Abstract
The precipitation of calcium oxalate monohydrate (COM) was monitored at a Langmuir monolayer containing lipid raft domains. The raft-forming monolayer consists of a 2:1:1 mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/sphingomyelin/dihydrocholesterol, where the raft liquid ordered phase is enriched in sphingomyelin and the sterol. COM crystals, monitored by Brewster angle microscopy, appear at the phase boundary between the raft domains and the expanded phase.
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Affiliation(s)
- Isa O Benítez
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA
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49
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Geisse N, Cover T, Henderson R, Edwardson J. Targeting of Helicobacter pylori vacuolating toxin to lipid raft membrane domains analysed by atomic force microscopy. Biochem J 2004; 381:911-7. [PMID: 15128269 PMCID: PMC1133903 DOI: 10.1042/bj20031719] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Revised: 04/30/2004] [Accepted: 05/06/2004] [Indexed: 11/17/2022]
Abstract
The Helicobacter pylori vacuolating toxin VacA causes several effects on mammalian cells in vitro, including intracellular vacuolation, formation of pores in the plasma membrane and apoptosis. When added to cells, VacA becomes associated with detergent-resistant membranes, indicating that it binds preferentially to lipid rafts. In the present study, we have used atomic force microscopy to examine directly the association of VacA with lipid domains in supported lipid bilayers. VacA did not bind to lipid bilayers at pH 7.6. In contrast, at pH 4.0, VacA associated with the bilayers in the form of 26-nm oligomeric complexes. VacA bound to bilayers produced from either brain lipids or SM (sphingomyelin) plus cholesterol, each of which lacked detectable lipid domains. Bilayers composed of DOPC (dioleoylphosphatidylcholine), SM and cholesterol contained clearly visible raft-like domains, and VacA preferentially associated with these rafts. VacA bound poorly to raft-like domains in DOPC/SM bilayers, indicating that cholesterol is required for efficient association of VacA with lipid domains. When PS (phosphatidylserine), an anionic phospholipid that does not partition significantly into rafts, was added to the mixture of DOPC, SM and cholesterol, VacA was excluded from the rafts, indicating that it binds more avidly to PS than to the raft components. A typical plasma membrane exhibits pronounced lipid asymmetry, with SM enriched in the outer leaflet and PS in the inner leaflet. Therefore it is probable that the association of VacA with rafts in DOPC/SM/cholesterol bilayers represents a useful model for understanding the interactions of VacA with membranes in vivo.
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Affiliation(s)
- Nicholas A. Geisse
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Timothy L. Cover
- †Departments of Medicine and Microbiology and Immunology, Vanderbilt University School of Medicine and Veterans Affairs Medical Center, Nashville, TN 37232, U.S.A
| | - Robert M. Henderson
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - J. Michael Edwardson
- *Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
- To whom correspondence should be addressed (e-mail )
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Berquand A, Mingeot-Leclercq MP, Dufrêne YF. Real-time imaging of drug-membrane interactions by atomic force microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1664:198-205. [PMID: 15328052 DOI: 10.1016/j.bbamem.2004.05.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 05/25/2004] [Accepted: 05/28/2004] [Indexed: 11/30/2022]
Abstract
Understanding drug-biomembrane interactions at high resolution is a key issue in current biophysical and pharmaceutical research. Here we used real-time atomic force microscopy (AFM) imaging to visualize the interaction of the antibiotic azithromycin with lipid domains in model biomembranes. Various supported lipid bilayers were prepared by fusion of unilamellar vesicles on mica and imaged in buffer solution. Phase-separation was observed in the form of domains made of dipalmitoylphosphatidylcholine (DPPC), sphingomyelin (SM), or SM/cholesterol (SM/Chl) surrounded by a fluid matrix of dioleoylphosphatidylcholine (DOPC). Time-lapse images collected following addition of 1 mM azithromycin revealed progressive erosion and disappearance of DPPC gel domains within 60 min. We attribute this effect to the disruption of the tight molecular packing of the DPPC molecules by the drug, in agreement with earlier biophysical experiments. By contrast, SM and SM-Chl domains were not modified by azithromycin. We suggest that the higher membrane stability of SM-containing domains results from stronger intermolecular interactions between SM molecules. This work provides direct evidence that the perturbation of lipid domains by azithromycin strongly depends on the lipid nature and opens the door for developing new applications in membrane biophysics and pharmacology.
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Affiliation(s)
- A Berquand
- Unité de chimie des interfaces, Université catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium
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