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Colmano N, Sánchez-Borzone ME, Turina AV. Effects of Fipronil and surface behavior of neuronal insect and mammalian membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183979. [PMID: 35654149 DOI: 10.1016/j.bbamem.2022.183979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 04/25/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Nicolás Colmano
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Departamento de Química, Cátedra de Química Biológica, Córdoba, Argentina; Instituto de Investigaciones Biológicas y Tecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mariela E Sánchez-Borzone
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Departamento de Química, Cátedra de Química Biológica, Córdoba, Argentina; Instituto de Investigaciones Biológicas y Tecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Anahí V Turina
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Departamento de Química, Cátedra de Química Biológica, Córdoba, Argentina; Instituto de Investigaciones Biológicas y Tecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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2
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Pusterla JM, Cannas SA, Schneck E, Oliveira RG. Purified myelin lipids display a critical mixing point at low surface pressure. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183874. [PMID: 35120896 DOI: 10.1016/j.bbamem.2022.183874] [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: 10/29/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Lipids extracted from Purified Myelin Membranes (LPMM) were spread as monomolecular films at the air/aqueous interface. The films were visualized by Brewster Angle Microscopy (BAM) at different lateral pressures (π) and ionic environments. Coexistence of Liquid-Expanded (LE) and cholesterol-enriched (CE) rounded domains persisted up to π ≈ 5 mN/m but the monolayers became homogeneous at higher surface pressures. Before mixing, the domains distorted to non-rounded domains. We experimentally measured the line tension (λ) for the lipid monolayers at the domain borders by a shape relaxation technique using non-homogeneous electric fields. Regardless of the subphase conditions, the obtained line tensions are of the order of pN and tended to decrease as lateral pressure increased toward the mixing point. From the mean square displacement of nested trapped domains, we also calculated the dipole density difference between phases (μ). A non-linear drop was detected in this parameter as the mixing point is approached. Here we quantitively evaluated the π-dependance of both parameters with proper power laws in the vicinity of the critical mixing surface pressure, and the exponents showed to be consistent with a critical phenomenon in the two-dimensional Ising universality class. This idea of bidimensionality was found to be compatible only for simplified lipidic systems, while for whole myelin monolayers, that means including proteins, no critical mixing point was detected. Finally, the line tension values were related with the thickness differences between phases (Δt) near the critical point.
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Affiliation(s)
- Julio M Pusterla
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina; Institut für Physik Kondensierter Materie, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Sergio A Cannas
- Instituto de Física Enrique Gaviola (IFEG-CONICET), Facultad de Matemática Astronomía Física y Computación, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.
| | - Emanuel Schneck
- Institut für Physik Kondensierter Materie, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
| | - Rafael G Oliveira
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
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3
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Ionic environment, thickness and line tension as determinants of phase separation in whole Purified Myelin Membranes monolayers. Colloids Surf B Biointerfaces 2021; 207:112027. [PMID: 34388613 DOI: 10.1016/j.colsurfb.2021.112027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/14/2021] [Accepted: 08/03/2021] [Indexed: 11/24/2022]
Abstract
Purified myelin membranes (PMM) were spread as monomolecular films at the air/aqueous solution interface, and visualized by Brewster Angle Microscopy (BAM) at different lateral pressures (π) on three specific aqueous solutions: absence of salts, physiological conditions and presence of calcium. Coexistence of Liquid-Expanded (LE) and Liquid Ordered (LO) phases persisted up to collapse in the presence of salts, whereas monolayers became homogeneous at π ≥ 35-40 mN/m when salts are absent. This PMM phase-mixing behavior in monolayers is similar to the previously reported behavior of PMM multilamellar vesicles. Reflectivities (Rp) of p-polarized light from both phases were assessed throughout the whole π -range, and film thicknesses (t) were calculated from the Rp values and measured film refractive indices (n). The LO phase was found to be more reflective and thicker than the LE phase at π ≤ 15 mN/m, but less reflective and thinner at higher π. We also determined the line tension (λ) of PMM monolayers at the domain boundaries from the rate of domain shape relaxation, which turned out to be of the order of picoNewtons (pN) and decreased as π increased. A correlation between λ and thickness differences (Δt) was found, suggesting that Δt is a molecular determinant for λ in PMM monolayers. Both λ and Δt were found to increase markedly when calcium was present in the subphase. This result corroborates the concept of divalent cations as a stabilizing factor for phase separation, in line with earlier studies on this mixture forming multilamellar membrane arrangements.
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4
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Chachaj-Brekiesz A, Wnętrzak A, Włodarska S, Lipiec E, Dynarowicz-Latka P. Molecular insight into neurodegeneration - Langmuir monolayer study on the influence of oxysterols on model myelin sheath. J Steroid Biochem Mol Biol 2020; 202:105727. [PMID: 32682060 DOI: 10.1016/j.jsbmb.2020.105727] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/08/2020] [Accepted: 07/13/2020] [Indexed: 02/06/2023]
Abstract
Systematic studies on the influence of selected ring-oxidized (7α-hydroxycholesterol, 7α-OH; 7β-hydroxycholesterol, 7β-OH; 7-ketocholesterol, 7-K) and chain-oxidized (25-OH) sterols on lipid layer of myelin were performed. Myelin sheath was modeled as five-component Langmuir monolayer (Chol:PE:SM:PS:PC 50:20:12:9:9). Particular oxysterols have been incorporated into the model myelin sheath by replacing cholesterol totally or partially (1:1). The effect of oxysterol incorporation was characterized with surface pressure and electric surface potential - area isotherms and visualized with Brewster angle microscopy (BAM) and atomic force microscopy (AFM). It has been noticed that model myelin loses its homogeneous structure (due to the appearance of domains) at physiological bilayer conditions (30-35 mN/m). In the presence of oxysterols, the fluidity of myelin model increases and the organization of lipids is altered, which is reflected in the decrease of electric surface potential changes (ΔV). The strongest myelin/oxysterol interactions have been observed for 7-K and 25-OH, being the most cytotoxic oxysterols found in biological tests.
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Affiliation(s)
- Anna Chachaj-Brekiesz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
| | - Anita Wnętrzak
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Sara Włodarska
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Ewelina Lipiec
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland
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5
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Träger J, Widder K, Kerth A, Harauz G, Hinderberger D. Effect of Cholesterol and Myelin Basic Protein (MBP) Content on Lipid Monolayers Mimicking the Cytoplasmic Membrane of Myelin. Cells 2020; 9:cells9030529. [PMID: 32106542 PMCID: PMC7140459 DOI: 10.3390/cells9030529] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/16/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Myelin basic protein (MBP) is located in the insulating covers of nerve cells in the brain and spinal cord. By interacting with lipid membranes, it is responsible for compaction of the myelin sheath in the central nervous system, which is weakened in demyelinating diseases. The lipid composition of the myelin leaflet has a high impact on the interaction between the membrane and MBP. Cholesterol is present in the cytoplasmic leaflet with a rather high amount of 44% (mol%). In this study, the focus is on the effect of cholesterol, mainly by varying its content, on the interaction of MBP with a lipid monolayer. Therefore, Langmuir lipid monolayers mimicking the cytoplasmic membrane of myelin and monolayers with variations of cholesterol content between 0% and 100% were measured at the air/water interface with additional imaging by fluorescence microscopy. All experiments were performed with and without bovine MBP to study the dependence of the interaction of the protein with the monolayers on the cholesterol content. The native amount of 44% cholesterol in the monolayer combines optima in the order of the monolayer (presumably correlating to compaction and thermodynamic stability) and protein interaction and shows unique features in comparison to lower or higher cholesterol contents.
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Affiliation(s)
- Jennica Träger
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Katharina Widder
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Andreas Kerth
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - George Harauz
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada;
| | - Dariush Hinderberger
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany; (J.T.); (K.W.); (A.K.)
- Interdisciplinary Research Center HALOmem at the Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
- Correspondence: ; Tel.: +49-345-55-25230
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6
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Pusterla JM, Schneck E, Funari SS, Démé B, Tanaka M, Oliveira RG. Cooling induces phase separation in membranes derived from isolated CNS myelin. PLoS One 2017; 12:e0184881. [PMID: 28915267 PMCID: PMC5600379 DOI: 10.1371/journal.pone.0184881] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 09/03/2017] [Indexed: 12/05/2022] Open
Abstract
Purified myelin membranes (PMMs) are the starting material for biochemical analyses such as the isolation of detergent-insoluble glycosphingolipid-rich domains (DIGs), which are believed to be representatives of functional lipid rafts. The normal DIGs isolation protocol involves the extraction of lipids under moderate cooling. Here, we thus address the influence of cooling on the structure of PMMs and its sub-fractions. Thermodynamic and structural aspects of periodic, multilamellar PMMs are examined between 4°C and 45°C and in various biologically relevant aqueous solutions. The phase behavior is investigated by small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC). Complementary neutron diffraction (ND) experiments with solid-supported myelin multilayers confirm that the phase behavior is unaffected by planar confinement. SAXS and ND consistently show that multilamellar PMMs in pure water become heterogeneous when cooled by more than 10–15°C below physiological temperature, as during the DIGs isolation procedure. The heterogeneous state of PMMs is stabilized in physiological solution, where phase coexistence persists up to near the physiological temperature. This result supports the general view that membranes under physiological conditions are close to critical points for phase separation. In presence of elevated Ca2+ concentrations (> 10 mM), phase coexistence is found even far above physiological temperatures. The relative fractions of the two phases, and thus presumably also their compositions, are found to vary with temperature. Depending on the conditions, an “expanded” phase with larger lamellar period or a “compacted” phase with smaller lamellar period coexists with the native phase. Both expanded and compacted periods are also observed in DIGs under the respective conditions. The observed subtle temperature-dependence of the phase behavior of PMMs suggests that the composition of DIGs is sensitive to the details of the isolation protocol.
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Affiliation(s)
- Julio M. Pusterla
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
| | - Emanuel Schneck
- Biomaterials Department, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | | | - Bruno Démé
- Institut Laue-Langevin (ILL), Grenoble, France
| | - Motomu Tanaka
- Biophysical Chemistry II, Institute of Physical Chemistry and BIOQUANT, University of Heidelberg, Heidelberg, Germany
- Institute for Integrated Cell-Material Sciences (WPI iCeMS), Kyoto University, Kyoto, Japan
| | - Rafael G. Oliveira
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC)-Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
- * E-mail:
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7
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The many faces (and phases) of ceramide and sphingomyelin II - binary mixtures. Biophys Rev 2017; 9:601-616. [PMID: 28823080 DOI: 10.1007/s12551-017-0298-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 07/27/2017] [Indexed: 12/31/2022] Open
Abstract
A rather widespread idea on the functional importance of sphingolipids in cell membranes refers to the occurrence of ordered domains enriched in sphingomyelin and ceramide that are largely assumed to exist irrespective of the type of N-acyl chain in the sphingolipid. Ceramides and sphingomyelins are the simplest kind of two-chained sphingolipids and show a variety of species, depending on the fatty acyl chain length, hydroxylation, and unsaturation. Abundant evidences have shown that variations of the N-acyl chain length in ceramides and sphingomyelins markedly affect their phase state, interfacial elasticity, surface topography, electrostatics, and miscibility, and that even the usually conceived "condensed" sphingolipids and many of their mixtures may exhibit liquid-like expanded states. Their lateral miscibility properties are subtlety regulated by those chemical differences. Even between ceramides with different acyl chain length, their partial miscibility is responsible for a rich two-dimensional structural variety that impacts on the membrane properties at the mesoscale level. In this review, we will discuss the miscibility properties of ceramide, sphingomyelin, and glycosphingolipids that differ in their N-acyl or oligosaccharide chains. This work is a second part that accompanies a previous overview of the properties of membranes formed by pure ceramides or sphingomyelins, which is also included in this Special Issue.
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8
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Bernardino de la Serna J, Hansen S, Berzina Z, Simonsen AC, Hannibal-Bach HK, Knudsen J, Ejsing CS, Bagatolli LA. Compositional and structural characterization of monolayers and bilayers composed of native pulmonary surfactant from wild type mice. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2450-9. [PMID: 23867774 DOI: 10.1016/j.bbamem.2013.07.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/23/2013] [Accepted: 07/08/2013] [Indexed: 01/12/2023]
Abstract
This work comprises a structural and dynamical study of monolayers and bilayers composed of native pulmonary surfactant from mice. Spatially resolved information was obtained using fluorescence (confocal, wide field and two photon excitation) and atomic force microscopy methods. Lipid mass spectrometry experiments were also performed in order to obtain relevant information on the lipid composition of this material. Bilayers composed of mice pulmonary surfactant showed coexistence of distinct domains at room temperature, with morphologies and lateral packing resembling the coexistence of liquid ordered (lo)/liquid disordered (ld)-like phases reported previously in porcine lung surfactant. Interestingly, the molar ratio of saturated (mostly DPPC)/non-saturated phospholipid species and cholesterol measured in the innate material corresponds with that of a DOPC/DPPC/cholesterol mixture showing lo/ld phase coexistence at a similar temperature. This suggests that at quasi-equilibrium conditions, key lipid classes in this complex biological material are still able to produce the same scaffold observed in relevant but simpler model lipid mixtures. Also, robust structural and dynamical similarities between mono- and bi-layers composed of mice pulmonary surfactant were observed when the monolayers reach a surface pressure of 30mN/m. This value is in line with theoretically predicted and recently measured surface pressures, where the monolayer-bilayer equivalence occurs in samples composed of single phospholipids. Finally, squeezed out material attached to pulmonary surfactant monolayers was observed at surface pressures near the beginning of the monolayer reversible exclusion plateau (~40mN/m). Under these conditions this material adopts elongated tubular shapes and displays ordered lateral packing as indicated by spatially resolved LAURDAN GP measurements.
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Affiliation(s)
- Jorge Bernardino de la Serna
- MEMPHYS, Center of Biomembrane Physics, University of Southern Denmark, Odense, Denmark; Membrane Biophysics and Biophotonics group, University of Southern Denmark, Odense, Denmark; Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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9
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Michanek A, Yanez M, Wacklin H, Hughes A, Nylander T, Sparr E. RNA and DNA association to zwitterionic and charged monolayers at the air-liquid interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:9621-9633. [PMID: 22624628 DOI: 10.1021/la204431q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The objective of this work is to establish under which conditions short RNA molecules (similar to miRNA) associate with zwitterionic phospholipids and how this differs from the association with cationic surfactants. We study how the base pairing (i.e., single stranded versus double stranded nucleic acids) and the length of the nucleic acid and the charge of the lipid/surfactant monolayer affect the association behavior. For this purpose, we study the adsorption of nucleic acids to monolayers composed of dipalmitoyl phosphatidylcholine (DPPC) or dioctadecyl-dimethyl-ammoniumbromide (DODAB) using the surface film balance, neutron reflectometry, and fluorescence microscopy. The monolayer studies with the surface film balance suggested that short single-stranded ssRNA associates with liquid expanded zwitterionic phospholipid monolayers, whereas less or no association is detected for double-stranded dsRNA and dsDNA. In order to quantify the interaction and to determine the location of the nucleic acid in the lipid/surfactant monolayer we performed neutron reflectometry measurements. It was shown that ssRNA adsorbs to and penetrates the liquid expanded monolayers, whereas there is no penetration of nucleic acids into the liquid condensed monolayer. No adsorption was detected for dsDNA to zwitterionic monolayers. On the basis of these results, we propose that the association is driven by the hydrophobic interactions between the exposed hydrophobic bases of the ssRNA and the hydrocarbon chains of the phospholipids. The addition of ssRNA also influences domain formation in the DPPC monolayer, leading to fractal-like interconnected domains. The experimental results are discussed in terms of the implication for biological processes and new leads for applications in medicine and biotechnology.
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Affiliation(s)
- Agnes Michanek
- Division of Physical Chemistry, Center of Chemistry and Chemical Engineering, Lund University, P.O. Box 124, 22100 Lund, Sweden
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10
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Self-segregation of myelin membrane lipids in model membranes. Biophys J 2012; 101:2713-20. [PMID: 22261060 DOI: 10.1016/j.bpj.2011.10.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 09/23/2011] [Accepted: 10/24/2011] [Indexed: 01/14/2023] Open
Abstract
Rapid conduction of nerve impulses requires coating of axons by myelin sheaths, which are multilamellar, lipid-rich membranes produced by oligodendrocytes in the central nervous system. To act as an insulator, myelin has to form a stable and firm membrane structure. In this study, we have analyzed the biophysical properties of myelin membranes prepared from wild-type mice and from mouse mutants that are unable to form stable myelin. Using C-Laurdan and fluorescence correlation spectroscopy, we find that lipids are tightly organized and highly ordered in myelin isolated from wild-type mice, but not from shiverer and ceramide synthase 2 null mice. Furthermore, only myelin lipids from wild-type mice laterally segregate into physically distinct lipid phases in giant unilamellar vesicles in a process that requires very long chain glycosphingolipids. Taken together, our findings suggest that oligodendrocytes exploit the potential of lipids to self-segregate to generate a highly ordered membrane for electrical insulation of axons.
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11
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Oliveira RG, Schneck E, Funari SS, Tanaka M, Maggio B. Equivalent aqueous phase modulation of domain segregation in myelin monolayers and bilayer vesicles. Biophys J 2010; 99:1500-9. [PMID: 20816062 DOI: 10.1016/j.bpj.2010.06.053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/16/2010] [Accepted: 06/17/2010] [Indexed: 10/19/2022] Open
Abstract
Purified myelin can be spread as monomolecular films at the air/aqueous interface. These films were visualized by fluorescence and Brewster angle microscopy, showing phase coexistence at low and medium surface pressures (<20-30 mN/m). Beyond this threshold, the film becomes homogeneous or not, depending on the aqueous subphase composition. Pure water as well as sucrose, glycerol, dimethylsulfoxide, and dimethylformamide solutions (20% in water) produced monolayers that become homogeneous at high surface pressures; on the other hand, the presence of salts (NaCl, CaCl(2)) in Ringer's and physiological solution leads to phase domain microheterogeneity over the whole compression isotherm. These results show that surface heterogeneity is favored by the ionic milieu. The modulation of the phase-mixing behavior in monolayers is paralleled by the behavior of multilamellar vesicles as determined by small-angle and wide-angle x-ray scattering. The correspondence of the behavior of monolayers and multilayers is achieved only at high surface pressures near the equilibrium adsorption surface pressure; at lower surface pressures, the correspondence breaks down. The equilibrium surface tension on all subphases corresponds to that of the air/alkane interface (27 mN/m), independently on the surface tension of the clean subphase.
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Affiliation(s)
- Rafael G Oliveira
- Centro de Investigaciones en Química Biológica de Córdoba, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina.
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12
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Rosetti CM, Maggio B, Oliveira RG. The self-organization of lipids and proteins of myelin at the membrane interface. Molecular factors underlying the microheterogeneity of domain segregation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1665-75. [DOI: 10.1016/j.bbamem.2008.02.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 02/08/2008] [Accepted: 02/15/2008] [Indexed: 12/12/2022]
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13
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Maggio B, Borioli GA, Del Boca M, De Tullio L, Fanani ML, Oliveira RG, Rosetti CM, Wilke N. Composition-driven surface domain structuring mediated by sphingolipids and membrane-active proteins. Above the nano- but under the micro-scale: mesoscopic biochemical/structural cross-talk in biomembranes. Cell Biochem Biophys 2007; 50:79-109. [PMID: 17968678 DOI: 10.1007/s12013-007-9004-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
Abstract
Biomembranes contain a wide variety of lipids and proteins within an essentially two-dimensional structure. The coexistence of such a large number of molecular species causes local tensions that frequently relax into a phase or compositional immiscibility along the lateral and transverse planes of the interface. As a consequence, a substantial microheterogeneity of the surface topography develops and that depends not only on the lipid-protein composition, but also on the lateral and transverse tensions generated as a consequence of molecular interactions. The presence of proteins, and immiscibility among lipids, constitute major perturbing factors for the membrane sculpturing both in terms of its surface topography and dynamics. In this work, we will summarize some recent evidences for the involvement of membrane-associated, both extrinsic and amphitropic, proteins as well as membrane-active phosphohydrolytic enzymes and sphingolipids in driving lateral segregation of phase domains thus determining long-range surface topography.
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Affiliation(s)
- Bruno Maggio
- Departamento de Química Biológica, Facultad de Ciencias Químicas, Centro de Investigaciones en Química Biológica de Córdoba, Universidad Nacional de Córdoba - CONICET, Argentina.
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14
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Hu Y, Israelachvili J. Lateral reorganization of myelin lipid domains by myelin basic protein studied at the air-water interface. Colloids Surf B Biointerfaces 2007; 62:22-30. [PMID: 17997288 DOI: 10.1016/j.colsurfb.2007.09.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 09/10/2007] [Accepted: 09/10/2007] [Indexed: 01/01/2023]
Abstract
It has been speculated that adsorption of myelin basic protein (MBP) to the myelin lipid membrane leads to lateral reorganization of the lipid molecules within the myelin membrane. This hypothesis was tested in this study by surface pressure measurement and fluorescent imaging of a monolayer composed of a myelin lipid mixture. The properties of the lipid monolayer before and after addition of MBP into the subphase were monitored. Upon addition of MBP to the monolayer subphase, the surface pressure rose and significant rearrangement of the lipid domains was observed. These results suggest that binding and partial insertion of MBP into the lipid monolayer led to dramatic rearrangement and morphological changes of the lipid domains. A model of adsorption of MBP to the lipid domains and subsequent domain fusion promoted by minimization of electrostatic repulsion between the domains was proposed to account for the experimental observations. The significance of these results in light of the role of MBP in maintaining the myelin structural integrity is discussed.
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Affiliation(s)
- Yufang Hu
- Department of Molecular and Medical Pharmacology and Department of Urology, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA 90095, USA.
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15
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Abstract
Monolayers prepared from myelin conserve all the compositional complexity of the natural membrane when spread at the air-water interface. They show a complex pressure-dependent surface pattern that, on compression, changes from the coexistence of two liquid phases to a viscous fractal phase embedded in a liquid phase. We dissected the role of major myelin protein components, myelin basic protein (MBP), and Folch-Lees proteolipid protein (PLP) as crucial factors determining the structural dynamics of the interface. By analyzing mixtures of a single protein with the myelin lipids we found that MBP and PLP have different surface pressure-dependent behaviors. MBP stabilizes the segregation of two liquid phases at low pressures and becomes excluded from the film under compression, remaining adjacent to the interface. PLP, on the contrary, organizes a fractal-like pattern at all surface pressures when included in a monolayer of the protein-free myelin lipids but it remains mixed in the MBP-induced liquid phase. The resultant surface topography and dynamics is regulated by combined near to equilibrium and out-of-equilibrium effects. PLP appears to act as a surface skeleton for the whole components whereas MBP couples the structuring to surface pressure-dependent extrusion and adsorption processes.
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Affiliation(s)
- Carla M Rosetti
- Centro de Investigaciones en Química Biológica de Córdoba, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
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16
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Maggio B, Fanani ML, Rosetti CM, Wilke N. Biophysics of sphingolipids II. Glycosphingolipids: An assortment of multiple structural information transducers at the membrane surface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1922-44. [PMID: 16780791 DOI: 10.1016/j.bbamem.2006.04.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 04/11/2006] [Accepted: 04/25/2006] [Indexed: 10/24/2022]
Abstract
Glycosphingolipids are ubiquitous components of animal cell membranes. They are constituted by the basic structure of ceramide with its hydroxyl group linked to single carbohydrates or oligosaccharide chains of different complexity. The combination of the properties of their hydrocarbon moiety with those derived from the variety and complexity of their hydrophilic polar head groups confers to these lipids an extraordinary capacity for molecular-to-supramolecular transduction across the lateral/transverse planes in biomembranes and beyond. In our opinion, most of the advances made over the last decade on the biophysical behavior of glycosphingolipids can be organized into three related aspects of increasing structural complexity: (1) intrinsic codes: local molecular interactions of glycosphingolipids translated into structural self-organization. (2) Surface topography: projection of molecular shape and miscibility of glycosphingolipids into formation of coexisting membrane domains. (3) Beyond the membrane interface: glycosphingolipid as modulators of structural topology, bilayer recombination and surface biocatalysis.
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Affiliation(s)
- Bruno Maggio
- Departamento de Química Biológica - CIQUIBIC, Universidad Nacional de Córdoba - CONICET, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
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17
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Caseli L, Masui DC, Furriel RPM, Leone FA, Zaniquelli MED. Incorporation conditions guiding the aggregation of a glycosylphosphatidyl inositol (GPI)-anchored protein in Langmuir monolayers. Colloids Surf B Biointerfaces 2005; 46:248-54. [PMID: 16356698 DOI: 10.1016/j.colsurfb.2005.11.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 10/17/2005] [Accepted: 11/08/2005] [Indexed: 11/28/2022]
Abstract
This work investigates the process of incorporation of a glycosylphosphatidyl inositol (GPI)-anchored alkaline phosphatase into Langmuir monolayers of dimyristoyl phosphatidic acid (DMPA). Three different methods of protein incorporation were assayed. When the protein solution was injected below the air-water interface after formation of the lipid monolayer a micro-heterogeneous distribution of alkaline phosphatase throughout the interface was observed. Adsorption kinetics studied by fluorescence microscopy, associated with surface pressure measurements, led to the proposition of a model in which the protein penetration is modulated by the surface packing of the monolayer and intermolecular interactions occurring between the phospholipid and the protein. At initial surface pressures higher than 20 m Nm(-1), the protein is quickly adsorbed on the interface and the lateral diffusion drives the alkyl chains to turn towards the air phase while the polypeptide moiety faces the aqueous subphase.
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Affiliation(s)
- Luciano Caseli
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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18
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Maggio B, Rosetti CM, Borioli GA, Fanani ML, Del Boca M. Protein-mediated surface structuring in biomembranes. Braz J Med Biol Res 2005; 38:1735-48. [PMID: 16302088 DOI: 10.1590/s0100-879x2005001200002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The lipids and proteins of biomembranes exhibit highly dissimilar conformations, geometrical shapes, amphipathicity, and thermodynamic properties which constrain their two-dimensional molecular packing, electrostatics, and interaction preferences. This causes inevitable development of large local tensions that frequently relax into phase or compositional immiscibility along lateral and transverse planes of the membrane. On the other hand, these effects constitute the very codes that mediate molecular and structural changes determining and controlling the possibilities for enzymatic activity, apposition and recombination in biomembranes. The presence of proteins constitutes a major perturbing factor for the membrane sculpturing both in terms of its surface topography and dynamics. We will focus on some results from our group within this context and summarize some recent evidence for the active involvement of extrinsic (myelin basic protein), integral (Folch-Lees proteolipid protein) and amphitropic (c-Fos and c-Jun) proteins, as well as a membrane-active amphitropic phosphohydrolytic enzyme (neutral sphingomyelinase), in the process of lateral segregation and dynamics of phase domains, sculpturing of the surface topography, and the bi-directional modulation of the membrane biochemical reactivity.
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Affiliation(s)
- B Maggio
- Departamento de Química Biológica, CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
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19
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Oliveira RG, Tanaka M, Maggio B. Many length scales surface fractality in monomolecular films of whole myelin lipids and proteins. J Struct Biol 2005; 149:158-69. [PMID: 15681232 DOI: 10.1016/j.jsb.2004.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 11/09/2004] [Indexed: 11/30/2022]
Abstract
Monomolecular films prepared with all the lipid and protein components of myelin were spread at the air/aqueous buffer interface from isolated bovine spinal cord myelin fully dissolved in chloroform:methanol (2:1) or by surface free energy shock of myelin membrane microvesicles. These monolayers show indistinguishable surface behavior, with similar compositional phase coexistence through all the compression isotherm on several subphase conditions. The domains were observed through epifluorescence and Brewster angle microscopy on the air/water interface and on Langmuir-Blodgett films. Their thickness was measured ellipsometrically. Under molecular packing conditions resembling those found in the natural membrane, the morphology and size of the domains are highly self-similar, displaying no characteristic length scale. These properties are the hallmark of fractal objects. The fractality extends at least three orders of magnitudes, from the micrometer to the millimeter range, the fractal dimension being about 1.7. A possible implication of fractality in membrane structure and/or function is demonstrated through the high fluctuation of the propagation of signals through constrained diffusion in corrals formed by domains in the plane of the monolayer, which restricts the diffusion of a fluorescent probe over many length scale domains.
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Affiliation(s)
- Rafael G Oliveira
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina
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20
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Rosetti CM, Oliveira RG, Maggio B. The Folch-Lees proteolipid induces phase coexistence and transverse reorganization of lateral domains in myelin monolayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1668:75-86. [PMID: 15670733 DOI: 10.1016/j.bbamem.2004.11.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Revised: 11/11/2004] [Accepted: 11/16/2004] [Indexed: 11/16/2022]
Abstract
Solvent solubilized myelin membranes spread as monomolecular layers at the air-water interface show a heterogeneous pattern at all surface pressures. In order to asses the role of myelin protein and lipid components in the surface structuring we compared the topography, as seen by Brewster angle microscopy (BAM) and epifluorescence microscopy, of monolayers made from mixtures containing all myelin lipids (except gangliosides) and variable proportions of Folch-Lees proteolipid protein (PLP, the major protein component of myelin). The presence of the single PLP, in the absence of the other myelin proteins, can reproduce the surface pattern of the whole myelin extract films in a concentration-dependant manner. Moreover, a threshold mole fraction of PLP is necessary to induce the lipid-protein component reorganization leading to the appearance of a rigid (gray) phase, acting as a surface skeleton, at low surface pressures and of fractal clusters at high surface pressures. The average size of those clusters is also dependent on the PLP content in the monolayer and on the time elapsed from the moment of film spreading, as they apparently result from an irreversible lateral aggregation process. The transverse rearrangement of the monolayer occurring under compression was different in films with the highest and lowest PLP mole fractions tested.
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Affiliation(s)
- C M Rosetti
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
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21
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Oliveira RG, Maggio B. Surface behavior, microheterogeneity and adsorption equilibrium of myelin at the air-water interface. Chem Phys Lipids 2003; 122:171-6. [PMID: 12598049 DOI: 10.1016/s0009-3084(02)00187-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Interfacial films of whole myelin membrane adsorb at the air-water interface from myelin vesicles. The films show a liquid state and their equilibrium spreading pressure is equal to the collapse pressure (about 47 mN/m). The films appear microheterogeneous as seen by epifluorescence microscopy, consisting in two liquid phases over all the adsorption isotherm, starting with rounded liquid expanded domains (low surface pressure) immersed in a cholesterol enriched phase and reaching a fractal pattern at high surface pressure similar to those previously observed by compressing the film. Vesicles adsorb to the interfacial film mainly at the lateral interfaces. The high surface pressure at equilibrium (almost equal to the collapse pressure) indicates the formation of surface multilayers, also shown by fluorescence microscopy.
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Affiliation(s)
- Rafael G Oliveira
- Facultad de Ciencias Químicas, Departamento de Química Biológica-CIQUIBIC, Universidad Nacional de Córdoba, 5000 Cordoba, Argentina
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22
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Bagatolli LA. Thermotropic behavior of lipid mixtures studied at the level of single vesicles: giant unilamellar vesicles and two-photon excitation fluorescence microscopy. Methods Enzymol 2003; 367:233-53. [PMID: 14611068 DOI: 10.1016/s0076-6879(03)67015-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Luis A Bagatolli
- Center for Biomembrane Physics, Department of Biochemistry and Molecular Biology, Campusvej 55, DK-5230 Odense M, Denmark
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23
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Maggio B, Fanani ML, Oliveira RG. Biochemical and structural information transduction at the mesoscopic level in biointerfaces containing sphingolipids. Neurochem Res 2002; 27:547-57. [PMID: 12374189 DOI: 10.1023/a:1020203512287] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this work we describe two aspects of molecular and supramolecular information transduction. The first is the biochemical and structural information content and transduction associated with sphingomyelinase activity. The results disclose a lipid-mediated cross-communication between the sphingomyelinase and phospholipase A2 pathways. In addition, the two-dimensional degradation of sphingomyelin by sphingomyelinase affects the surface topography and the latter modulates the enzyme activity. The second is the information contained in the compositionally driven lateral organization of whole glial and neuronal membrane interfaces. The myelin monolayer exhibits microheterogeneous topographical structuring and nonhomogeneous lateral thickness of phase separated regions, depending dynamically on the lateral surface pressure. On the other hand, the differential response of functional living cells depends on information contained in the molecular organization of the contacting membrane interface.
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Affiliation(s)
- Bruno Maggio
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Argentina.
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24
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Oliveira RG, Maggio B. Compositional domain immiscibility in whole myelin monolayers at the air-water interface and Langmuir-Blodgett films. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1561:238-50. [PMID: 11997124 DOI: 10.1016/s0005-2736(02)00350-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Monomolecular layers of whole myelin membrane can be formed at the air-water interface from vesicles or from solvent solution of myelin. The films appear microheterogeneous as seen by epifluorescence and Brewster angle microscopy. The pattern consists mainly of two coexisting liquid phases over the whole compression isotherm. The liquid nature of the phases is apparent from the fluorescent probe behavior, domain mobility, deformability and boundary relaxation due to the line tension of the surface domains. The monolayers were transferred to alkylated glass and fluorescently labeled against myelin components. The immunolabeling of two major proteins of myelin (myelin basic protein, proteolipid-DM20) and of 2',3'-cyclic nucleotide 3'-phosphodiesterase shows colocalization with probes partitioning preferentially in liquid-expanded lipid domains also containing ganglioside G(M1). A different phase showing an enrichment in cholesterol, galactocerebroside and phosphatidylserine markers is also found. The distribution of components is qualitatively independent of the lateral surface pressure and is generally constituted by one phase enriched in charged components in an expanded state coexisting with another phase enriched in non-charged constituents of lower compressibility. The domain immiscibility provides a physical basis for the microheterogeneity found in this membrane model system.
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Affiliation(s)
- Rafael G Oliveira
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina
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