1
|
Rodi PM, Maggio B, Bagatolli LA. Direct visualization of the lateral structure of giant vesicles composed of pseudo-binary mixtures of sulfatide, asialo-GM1 and GM1 with POPC. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:544-555. [PMID: 29106974 DOI: 10.1016/j.bbamem.2017.10.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 11/16/2022]
Abstract
We compared the lateral structure of giant unilamellar vesicles (GUVs) composed of three pseudo binary mixtures of different glycosphingolipid (GSL), i.e. sulfatide, asialo-GM1 or GM1, with POPC. These sphingolipids possess similar hydrophobic residues but differ in the size and charge of their polar head group. Fluorescence microscopy experiments using LAURDAN and DiIC18 show coexistence of micron sized domains in a molar fraction range that depends on the nature of the GSLs. In all cases, experiments with LAURDAN show that the membrane lateral structure resembles the coexistence of solid ordered and liquid disordered phases. Notably, the overall extent of hydration measured by LAURDAN between the solid ordered and liquid disordered membrane regions show marked similarities and are independent of the size of the GSL polar head group. In addition, the maximum amount of GSL incorporated in the POPC bilayer exhibits a strong dependence on the size of the GSL polar head group following the order sulfatide>asialo-GM1>GM1. This observation is in full harmony with previous experiments and theoretical predictions for mixtures of these GSL with glycerophospholipids. Finally, compared with previous results reported in GUVs composed of mixtures of POPC with the sphingolipids cerebroside and ceramide, we observed distinctive curvature effects at particular molar fraction regimes in the different mixtures. This suggests a pronounced effect of these GSL on the spontaneous curvature of the bilayer. This observation may be relevant in a biological context, particularly in connection with the highly curved structures found in neural cells.
Collapse
Affiliation(s)
- Pablo M Rodi
- MEMPHYS - Center for Biomembrane Physics, Denmark; Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Argentina
| | - Bruno Maggio
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
| | - Luis A Bagatolli
- MEMPHYS - Center for Biomembrane Physics, Denmark; Yachay EP/Yachay Tech University, San Miguel de Urcuqui, Ecuador.
| |
Collapse
|
2
|
De Tullio L, Fanani ML, Maggio B. Surface mixing of products and substrate of PLA2 in enzyme-free mixed monolayers reproduces enzyme-driven structural topography. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2056-63. [DOI: 10.1016/j.bbamem.2013.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 05/02/2013] [Accepted: 05/20/2013] [Indexed: 11/15/2022]
|
3
|
Ibarguren M, Sot J, Montes LR, Vasil AI, Vasil ML, Goñi FM, Alonso A. Recruitment of a phospholipase C/sphingomyelinase into non-lamellar lipid droplets during hydrolysis of lipid bilayers. Chem Phys Lipids 2012; 166:12-7. [PMID: 23253877 DOI: 10.1016/j.chemphyslip.2012.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 11/30/2012] [Accepted: 12/01/2012] [Indexed: 01/05/2023]
Abstract
When giant unilamellar vesicles (GUVs) composed of sphingomyelin, phosphatidylcholine, phosphatidylethanolamine, and cholesterol are treated with PlcHR(2), a phospholipase C/sphingomyelinase from Pseudomonas aeruginosa, the initial stages of lipid hydrolysis do not cause large changes in vesicle morphology (Ibarguren et al., 2011). However, when hydrolysis progresses confocal fluorescence microscopy reveals the formation of lipid aggregates, whose morphology is not compatible with that of bilayers. Smaller vesicles or droplets can also be seen inside the GUV. Our studies indicate that these aggregates or droplets are enriched in the non-lamellar lipid ceramide, an end-product of PlcHR(2) reaction. Moreover, the aggregates/droplets appear enriched in the hydrolytic enzyme PlcHR(2). At a final stage GUVs containing the enzyme-enriched droplets disintegrate and vanish from the microscope field. The observed non-lamellar enzyme-rich structures may be related to intermediates in the process of aggregation and fusion although the experimental design prevents vesicle free diffusion in the aqueous medium, thus actual aggregation or fusion cannot be observed.
Collapse
Affiliation(s)
- Maitane Ibarguren
- Unidad de Biofísica (Centro Mixto CSIS-UPV/EHU), Departamento de Bioquímica, Universidad del País Vasco, Barrio Sarriena s/n, 48940 Bilbao, Spain
| | | | | | | | | | | | | |
Collapse
|
4
|
Fanani ML, Hartel S, Maggio B, De Tullio L, Jara J, Olmos F, Oliveira RG. The action of sphingomyelinase in lipid monolayers as revealed by microscopic image analysis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1309-23. [DOI: 10.1016/j.bbamem.2010.01.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 12/16/2009] [Accepted: 01/04/2010] [Indexed: 11/26/2022]
|
5
|
De Tullio L, Maggio B, Fanani ML. Sphingomyelinase acts by an area-activated mechanism on the liquid-expanded phase of sphingomyelin monolayers. J Lipid Res 2008; 49:2347-55. [DOI: 10.1194/jlr.m800127-jlr200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
6
|
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.
Collapse
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.
| | | | | | | | | | | | | | | |
Collapse
|
7
|
De Tullio L, Maggio B, Hartel S, Jara J, Fanani ML. The initial surface composition and topography modulate sphingomyelinase-driven sphingomyelin to ceramide conversion in lipid monolayers. Cell Biochem Biophys 2007; 47:169-77. [PMID: 17652769 DOI: 10.1007/s12013-007-0001-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 01/28/2023]
Abstract
Changes of the initial composition and topography of mixed monolayers of Sphingomyelin and Ceramide modulate the degradation of Sphingomyelin by Bacillus cereus Sphingomyelinase. The presence of initial lateral phase boundary due to coexisting condensed and expanded phase domains favors the precatalytic steps of the reaction. The amount and quality of the domain lateral interface, defined by the type of boundary undulation, appears as a modulatory supramolecular code which regulates the catalytic efficiency of the enzyme. The long range domain lattice structuring is determined by the Sphingomyelinase activity.
Collapse
Affiliation(s)
- Luisina De Tullio
- Departamento de Química Biológica, Facultad de Ciencias Químicas - CONICET, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, República Argentina
| | | | | | | | | |
Collapse
|
8
|
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.
Collapse
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.
| | | | | | | |
Collapse
|
9
|
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.
Collapse
Affiliation(s)
- B Maggio
- Departamento de Química Biológica, CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
| | | | | | | | | |
Collapse
|
10
|
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.
Collapse
Affiliation(s)
- C M Rosetti
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
| | | | | |
Collapse
|
11
|
Borioli GA, Caputto BL, Maggio B. c-Fos and phosphatidylinositol-4,5-bisphosphate reciprocally reorganize in mixed monolayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1668:41-52. [PMID: 15670730 DOI: 10.1016/j.bbamem.2004.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 11/04/2004] [Accepted: 11/09/2004] [Indexed: 11/24/2022]
Abstract
The transcription factor c-Fos has surface thermodynamic properties that allow it to differentially interact with phospholipids, especially PIP2. It regulates phospholipid metabolism both in vivo and in vitro, and modulates degradation of phospholipid monolayers by phospholipases in a way that depends on the membrane intermolecular packing (i.e., surface lateral pressure). With the aim to understand details of the interactions of c-Fos at the membrane level, we studied the surface packing, dipole potential, compressibility and topography of mixed films of the protein with PIP2. We show that c-Fos changes the packing of liquid-expanded PIP2 monolayers, in a different manner with respect to its effect on the similarly liquid-expanded dilauroylphosphatidylcholine monolayers. The changes at the local molecular level are transduced to long-range inhomogeneities of the surface, detected by Brewster angle (BAM) and epifluorescence microscopy (EFM). Our results highlight the capacity of c-Fos to alter the packing and dipole potential of the lipid-protein interface. This involves variations of the surface in-plane elasticity and lateral segregation of phase domains. These dynamic, reversible alterations of surface organization provide a basis by which c-Fos may transduce molecular information at the membrane level.
Collapse
Affiliation(s)
- Graciela A Borioli
- CIQUIBIC-Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Pabellón Argentina-Ciudad Universitaria, 5000 Córdoba, Argentina.
| | | | | |
Collapse
|
12
|
Härtel S, Fanani ML, Maggio B. Shape transitions and lattice structuring of ceramide-enriched domains generated by sphingomyelinase in lipid monolayers. Biophys J 2004; 88:287-304. [PMID: 15489298 PMCID: PMC1305007 DOI: 10.1529/biophysj.104.048959] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sphingomyelinases (SMases) hydrolyze the membrane constituent sphingomyelin (SM) to phosphocholine and ceramide (Cer). Growing evidence supports that SMase-induced SM-->Cer conversion leads to the formation of lateral Cer-enriched domains which drive structural reorganization in lipid membranes. We previously provided visual evidence in real-time for the formation of Cer-enriched domains in SM monolayers through the action of the neutral Bacillus cereus SMase. In this work, we disclose a succession of discrete morphologic transitions and lateral organization of Cer-enriched domains that underlay the SMase-generated surface topography. We further reveal how these structural parameters couple to the generation of two-dimensional electrostatic fields, based upon the specific orientation of the lipid dipole moments in the Cer-enriched domains. Advanced image processing routines in combination with time-resolved epifluorescence microscopy on Langmuir monolayers revealed: 1), spontaneous nucleation and circular growth of Cer-enriched domains after injection of SMase into the subphase of the SM monolayer; 2), domain-intrinsic discrete transitions from circular to periodically undulating shapes followed by a second transition toward increasingly branched morphologies; 3), lateral superstructure organization into predominantly hexagonal domain lattices; 4), formation of super-superstructures by the hexagonal lattices; and 5), rotationally and laterally coupled domain movement before domain border contact. All patterns proved to be specific for the SMase-driven system since they could not be observed with Cer-enriched domains generated by defined mixtures of SM/Cer in enzyme-free monolayers at the same surface pressure (pi = 10 mN/m). Following the theories of lateral shape transitions, dipolar electrostatic interactions of lipid domains, and direct determinations of the monolayer dipole potential, our data show that SMase induces a domain-specific packing and orientation of the molecular dipole moments perpendicular to the air/water interface. In consequence, protein-driven generation of specific out-of-equilibrium states, an accepted concept for maintenance of transmembrane lipid asymmetry, must also be considered on the lateral level. Lateral enzyme-specific out-of-equilibrium organization of lipid domains represents a new level of signal transduction from local (nm) to long-range (microm) scales. The cross-talk between lateral domain structures and dipolar electrostatic fields adds new perspectives to the mechanisms of SMase-mediated signal transduction in biological membranes.
Collapse
Affiliation(s)
- Steffen Härtel
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas-CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina; and Centro de Estudios Científicos, Valdivia, Chile
| | - María Laura Fanani
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas-CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina; and Centro de Estudios Científicos, Valdivia, Chile
| | - Bruno Maggio
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas-CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina; and Centro de Estudios Científicos, Valdivia, Chile
| |
Collapse
|
13
|
Borioli GA, Caputto BL, Maggio B. Phospholipase activity is modulated by c-Fos through substrate expansion and hyperpolarization. FEBS Lett 2004; 570:82-6. [PMID: 15251444 DOI: 10.1016/j.febslet.2004.06.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Accepted: 06/09/2004] [Indexed: 10/26/2022]
Abstract
c-Fos, a component of AP-1 transcription factors, has been shown to have marked amphitropic properties and to regulate phospholipase activity against lipid monolayers. In agreement with its high surface activity, it has also been found to associate to membranes of the endoplasmic reticulum and to activate phospholipid metabolism in vivo. All these findings point to an involvement of this oncoprotein within a membrane environment. We have previously shown that c-Fos modulates in different manners the activity of phospholipase A2 and phospholipase C against monolayers of dilauroylphosphatidylcholine (PC). In this work, we have studied the possible molecular mechanism underlying the phosphohydrolytic modulation. Our results show that c-Fos expands and hyperpolarizes PC, indicating that its effects on these enzymatic activities are due to the changes it induces on the interfacial organization of the substrate.
Collapse
Affiliation(s)
- Graciela A Borioli
- CIQUIBIC, Departmento Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba Pabellón Argentina, Ciudad Universitaria, 5000 Córdoba, Argentina.
| | | | | |
Collapse
|
14
|
Interfacial behavior of glycosphingolipids and chemically related sphingolipids. Curr Opin Colloid Interface Sci 2004. [DOI: 10.1016/j.cocis.2004.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
15
|
Fanani ML, Härtel S, Oliveira RG, Maggio B. Bidirectional control of sphingomyelinase activity and surface topography in lipid monolayers. Biophys J 2002; 83:3416-24. [PMID: 12496108 PMCID: PMC1302416 DOI: 10.1016/s0006-3495(02)75341-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Lipid lateral organization is increasingly found to modulate membrane-bound enzymes. We followed in real time the reaction course of sphingomyelin (SM) degradation by Bacillus cereus sphingomyelinase (SMase) of lipid monolayers by epifluorescence microscopy. There is evidence that formation of ceramide (Cer), a lipid second messenger, drives structural reorganization of membrane lipids. Our results provide visual evidence that SMase activity initially alters surface topography by inducing phase separation into condensed (Cer-enriched) and expanded (SM-enriched) domains. The Cer-enriched phase grows steadily as the reaction proceeds at a constant rate. The surface topography derived from the SMase-driven reaction was compared with, and found to differ from, that of premixed SM/Cer monolayers of the same lipid composition, indicating that substantial information content is stored depending on the manner in which the surface was generated. The long-range topographic changes feed back on the kinetics of Smase, and the onset of condensed-phase percolation is temporally correlated with a rapid drop of reaction rate. These observations reveal a bidirectional influence and communication between effects taking place at the local molecular level and the supramolecular organization. The results suggest a novel biocatalytic-topographic mechanism in which a surface enzymatic activity can influence the function of amphitropic proteins important for cell function.
Collapse
Affiliation(s)
- María Laura Fanani
- Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
| | | | | | | |
Collapse
|
16
|
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.
Collapse
Affiliation(s)
- Bruno Maggio
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Argentina.
| | | | | |
Collapse
|
17
|
Chicano JJ, Ortiz A, Teruel JA, Aranda FJ. Organotin compounds promote the formation of non-lamellar phases in phosphatidylethanolamine membranes. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1558:70-81. [PMID: 11750266 DOI: 10.1016/s0005-2736(01)00426-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Organotin compounds are important contaminants in the environment. They are membrane active molecules with broad biological toxicity. We have studied the interaction of tri-n-butyltin chloride and tri-n-phenyltin chloride with model membranes composed of different phosphatidylethanolamines using differential scanning calorimetry, X-ray diffraction, 31P-nuclear magnetic resonance and infrared spectroscopy. Organotin compounds laterally segregate in phosphatidylethanolamine membranes without affecting the shape and position of the lamellar gel to lamellar liquid-crystalline phase transition thermogram of the phospholipid. This is in contrast with their reported effect on phosphatidylcholine membranes [Chicano et al. (2001) Biochim. Biophys. Acta 1510, 330-341] and emphasises the importance of the nature of the lipid headgroup in determining how the behaviour of lipid molecules is affected by these toxicants. Interestingly, we have found that organotin compounds disrupt the pattern of hydrogen-bonding in the interfacial region of dielaidoylphosphatidylethanolamine membranes and have the ability to promote the formation of hexagonal H(II) structures in this system. These results open the possibility that some of the specific toxic effects of organotin compounds might be exerted through the alteration of membrane function produced by their interaction with the lipidic component of the membrane.
Collapse
Affiliation(s)
- José J Chicano
- Departamento de Bioquímica y Biología Molecular 'A', Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100, Murcia, Spain
| | | | | | | |
Collapse
|
18
|
Carrer DC, Maggio B. Transduction to self-assembly of molecular geometry and local interactions in mixtures of ceramides and ganglioside GM1. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1514:87-99. [PMID: 11513807 DOI: 10.1016/s0005-2736(01)00366-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In mixed monolayers with ganglioside GM1, ceramide induces a non-ideal increase of the monolayer collapse pressure, a reduction of the mean molecular area and a decrease of the surface potential per molecule at all surface pressures. The critical packing parameter and van der Waals interaction energy calculated from monolayer data predict the transduction of changes from the molecular to the supramolecular level, such as formation of bilayers and possible subsequent facilitation of non-bilayer structures as the ceramide concentration increases, along with a greater thermal stability of the lipid structures. In agreement with the expectations from monolayer data, calorimetry, dynamic light scattering and electron microscopy data reveal the actual presence of phases with high phase-transition temperatures; at about 5 mol% ceramide in the mixture, the aggregates change their topology from micelles to multilamellar vesicles of increasing size and finally to long, thin tubules as the amount of ceramide in the system increases.
Collapse
Affiliation(s)
- D C Carrer
- Departamento de Química Biológica--CIQUIBIC, Facultad de Ciencias Químicas--CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina
| | | |
Collapse
|
19
|
Fanani ML, Maggio B. Kinetic steps for the hydrolysis of sphingomyelin by Bacillus cereus sphingomyelinase in lipid monolayers. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31977-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
20
|
Calderón RO, Eynard AR. Fatty acids specifically related to the anisotropic properties of plasma membrane from rat urothelium. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1483:174-84. [PMID: 10601706 DOI: 10.1016/s1388-1981(99)00173-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Four different luminal surfaces of rat urothelium differing in their fatty acid composition were prepared by dietary induction. In order to induce lipid changes, each of four groups of rat received a basal diet rich in one of the unsaturated n-3, n-6 or n-9 fatty acid families and a commercial (control) diet. The effects of the dietary regime on the fatty acid composition of luminal urothelial membranes and their relation to the mobility of fluorescent probes were studied. In comparison with the control diet membrane, all three fatty acid-rich diets induced a decrease of the percentage amount of saturated fatty acid while that of the unsaturated fatty acids was increased. Accordingly, all three diets increased the unsaturation index in comparison with the control diet. The anisotropy across each membrane fraction was assessed using the n-(9-anthroyloxy) fatty acid fluorescent probes 3-AS, 7-AS and 12-AS, which locate at different depths in the membrane. Two different anisotropy profiles were observed. One profile showed the highest anisotropy at the C7 depth, whereas the other exhibited a continuous decrease of the anisotropy from the surface to the center of the bilayer. The molecular properties (isomerization) of 18:2n-9 fatty acid may account, at least in part, for the observed V-shaped profile (the ascending trend) of the membrane anisotropy values as a function of the respective 18:2n-9 fatty acid contents. Nevertheless, the minimum value of the profile did not correspond to the minimum 18:2n-9 fatty acid content, but rather to the higher amount of docosahexaenoic (22:6n-3) fatty acid. Thus, a modulating role of the 22:6n-3 fatty acid on the rigidifying effect of 18:2n-9 fatty acid is suggested, possibly mediated by relationships between fatty acid composition, saturated and unsaturated chain lengths, and freedom of motion of the phospholipid acyl chains.
Collapse
Affiliation(s)
- R O Calderón
- Primera Cátedra de Histología, Embriología y Génetica, Instituto de Biología Celular, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Casilla de Correo Central 220, 5000, Córdoba, Argentina.
| | | |
Collapse
|
21
|
Maggio B. Modulation of phospholipase A2 by electrostatic fields and dipole potential of glycosphingolipids in monolayers. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)32128-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
22
|
Krishnamoorthy G. Probing the dynamics of planar supported membranes by Nile red fluorescence lifetime distribution. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1414:255-9. [PMID: 9804969 DOI: 10.1016/s0005-2736(98)00157-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The structure and dynamics of planar supported membranes were studied by using the fluorescence probe Nile red. The width of fluorescence lifetime distribution of Nile red was used to infer the heterogeneity of membranes. The width of fluorescence lifetime was larger and the lifetime was shorter in supported membranes when compared to vesicle membranes. This was interpreted as due to the presence of water-filled membrane discontinuity leading to a heterogeneous surface in supported membranes. Microdomain causing agents such as cholesterol, sphingomyelin, etc. caused a larger level of heterogeneity in supported membranes when compared to vesicle membranes.
Collapse
|
23
|
Fanani ML, Maggio B. Surface pressure-dependent cross-modulation of sphingomyelinase and phospholipase A2 in monolayers. Lipids 1998; 33:1079-87. [PMID: 9870902 DOI: 10.1007/s11745-998-0308-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated the ways in which phospholipase A2 and sphingomyelinase are mutually modulated at lipid interfaces. The activity of one enzyme is affected by its own reaction products and by substrates and products of the other enzyme; all this depends differently on the lateral surface pressure. Ceramide inhibits both the sphingomyelinase activity rate and the extent of degradation, and decreases the lag time at all surface pressures. Dilauroyl- and dipalmitoylphosphatidylcholine, the substrates of phospholipase A2 (PLA2), do not affect sphingomyelinase activity. The products of PLA2, palmitic acid and lysopalmitoylphosphatidylcholine, strongly enhance and shift to high surface pressures the activity optimum and the cutoff point of sphingomyelinase. Palmitic acid also shifts to high surface pressures the cut-off point of PLA2 activity. Sphingomyelin strongly inhibits PLA2 at surface pressures above 5 mN/m, while ceramide shifts the cut-off point and the activity optimum to high surface pressures. The sphingolipids increase the lag time of PLA2 at low surface pressures. Both phosphohydrolytic pathways involve different levels of control on precatalytic steps and on the rate of activity that appear independent on specific alterations of molecular packing and surface potential. The mutual lipid-mediated interfacial modulation between both phosphohydrolytic pathways indicates that phospholipid degradation may be self-amplified or dampened depending on subtle changes of surface pressure and composition.
Collapse
Affiliation(s)
- M L Fanani
- Departamento de Química Biológica - CIQUIBIC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
| | | |
Collapse
|
24
|
Maggio B. Molecular interactions of the major myelin glycosphingolipids and myelin basic protein in model membranes. Neurochem Res 1997; 22:475-81. [PMID: 9130259 DOI: 10.1023/a:1027367929081] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The molecular organization, interactions, phase state and membrane-membrane interactions of model membranes containing cerebroside (GalCer), sulfatide (Sulf) and myelin basic protein (MBP) were investigated. Sulf shows a larger cross-sectional area than GalCer, in keeping with the lateral electrostatic repulsions in the negatively charged polar head group. The interactions of GalCer with different phospholipids are similar while those with Sulf depend on the phosphoryl choline moiety in the phospholipid. MBP induces a decrease of the phase transition temperature in both lipids but with Sulf this occurs at lower proportions of MBP. In mixtures of Sulf with phosphatidylcholine MBP induces phase separation among Sulf-rich and PC-rich domains. Extensive apposition of bilayers containing Sulf is induced by MBP while GalCer interferes with this process. Few membrane interactions proceed to bilayer merging or whole bilayer fusion and the glycosphingolipids help preserve the membrane integrity.
Collapse
Affiliation(s)
- B Maggio
- Departamento de Química Biológica-CIQUIBIC, Facultad de Ciencias Químicas-CONICET, Universidad Nacional de Córdoba, Argentina
| |
Collapse
|
25
|
Fanani ML, Maggio B. Mutual modulation of sphingomyelinase and phospholipase A2 activities against mixed lipid monolayers by their lipid intermediates and glycosphingolipids. Mol Membr Biol 1997; 14:25-9. [PMID: 9160338 DOI: 10.3109/09687689709048166] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Sphingomyelinase activity against pure sphingomyelin monolayers is constant up to a surface pressure of 18 mN/m and falls above it. Sphingomyelinase- and phospholipase A2-mediated phosphohydrolytic pathways are mutually modulated by the presence of their respective substrates and products. At 15 mN/m non-substrate lipids such as ceramide at a mole fraction of 0.1 in mixed films with the pure substrate, inhibit the sphingomyelinase activity. Ganglioside GM1, another ceramide-containing complex sphingolipid, also inhibits sphingomyelinase activity, while a chemically related glycosphingolipid such as asialo-GM1 has no effect. The activity is unaltered by dipalmitoylphosphatidylcholine and by an equimolar mixture of its products of hydrolysis by phospholipase A2, fatty acid and lysoderivative, but it is inhibited by only one of them or by dilauroylphosphatidylcholine. Phospholipase A2 is inhibited by sphingomyelin, and activated by ceramide and by palmitic acid, one of the products of its own phosphohydrolytic reaction.
Collapse
Affiliation(s)
- M L Fanani
- Departamento de Quimica Biológica-CIQUIBIC, Facultad de Ciencias Químicas-CONICET, Universidad Nacional de Córdoba, Argentina
| | | |
Collapse
|