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Labeled chemical biology tools for investigating sphingolipid metabolism, trafficking and interaction with lipids and proteins. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:1161-73. [PMID: 24389251 DOI: 10.1016/j.bbalip.2013.12.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/10/2013] [Accepted: 12/17/2013] [Indexed: 12/17/2022]
Abstract
The unraveling of sphingolipid metabolism and function in the last 40 years relied on the extensive study of inherited human disease and specifically-tailored mouse models. However, only few of the achievements made so far would have been possible without chemical biology tools, such as fluorescent and/or radio-labeled and other artificial substrates, (mechanism-based) enzyme inhibitors, cross-linking probes or artificial membrane models. In this review we provide an overview over chemical biology tools that have been used to gain more insight into the molecular basis of sphingolipid-related biology. Many of these tools are still of high relevance for the investigation of current sphingolipid-related questions, others may stimulate the tailoring of novel probes suitable to address recent and future issues in the field. This article is part of a Special Issue entitled Tools to study lipid functions.
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Hofmann K, Thiele C, Schött HF, Gaebler A, Schoene M, Kiver Y, Friedrichs S, Lütjohann D, Kuerschner L. A novel alkyne cholesterol to trace cellular cholesterol metabolism and localization. J Lipid Res 2013; 55:583-91. [PMID: 24334219 DOI: 10.1194/jlr.d044727] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cholesterol is an important lipid of mammalian cells and plays a fundamental role in many biological processes. Its concentration in the various cellular membranes differs and is tightly regulated. Here, we present a novel alkyne cholesterol analog suitable for tracing both cholesterol metabolism and localization. This probe can be detected by click chemistry employing various reporter azides. Alkyne cholesterol is accepted by cellular enzymes from different biological species (Brevibacterium, yeast, rat, human) and these enzymes include cholesterol oxidases, hydroxylases, and acyl transferases that generate the expected metabolites in in vitro and in vivo assays. Using fluorescence microscopy, we studied the distribution of cholesterol at subcellular resolution, detecting the lipid in the Golgi and at the plasma membrane, but also in the endoplasmic reticulum and mitochondria. In summary, alkyne cholesterol represents a versatile, sensitive, and easy-to-use tool for tracking cellular cholesterol metabolism and localization as it allows for manifold detection methods including mass spectrometry, thin-layer chromatography/fluorography, and fluorescence microscopy.
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Affiliation(s)
- Kristina Hofmann
- Life and Medical Sciences Institute (LIMES), University of Bonn, D-53115 Bonn, Germany; and
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Nusshold C, Uellen A, Bernhart E, Hammer A, Damm S, Wintersperger A, Reicher H, Hermetter A, Malle E, Sattler W. Endocytosis and intracellular processing of BODIPY-sphingomyelin by murine CATH.a neurons. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1831:1665-78. [PMID: 23973266 PMCID: PMC3807659 DOI: 10.1016/j.bbalip.2013.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 08/01/2013] [Accepted: 08/06/2013] [Indexed: 01/24/2023]
Abstract
Neuronal sphingolipids (SL) play important roles during axonal extension, neurotrophic receptor signaling and neurotransmitter release. Many of these signaling pathways depend on the presence of specialized membrane microdomains termed lipid rafts. Sphingomyelin (SM), one of the main raft constituents, can be formed de novo or supplied from exogenous sources. The present study aimed to characterize fluorescently-labeled SL turnover in a murine neuronal cell line (CATH.a). Our results demonstrate that at 4°C exogenously added BODIPY-SM accumulates exclusively at the plasma membrane. Treatment of cells with bacterial sphingomyelinase (SMase) and back-exchange experiments revealed that 55-67% of BODIPY-SM resides in the outer leaflet of the plasma membrane. Endocytosis of BODIPY-SM occurs via caveolae with part of internalized BODIPY-fluorescence ending up in the Golgi and the ER. Following endocytosis BODIPY-SM undergoes hydrolysis, a reaction substantially faster than BODIPY-SM synthesis from BODIPY-ceramide. RNAi demonstrated that both, acid (a)SMase and neutral (n)SMases contribute to BODIPY-SM hydrolysis. Finally, high-density lipoprotein (HDL)-associated BODIPY-SM was efficiently taken up by CATH.a cells. Our findings indicate that endocytosis of exogenous SM occurs almost exclusively via caveolin-dependent pathways, that both, a- and nSMases equally contribute to neuronal SM turnover and that HDL-like particles might represent physiological SM carriers/donors in the brain.
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Affiliation(s)
- Christoph Nusshold
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Andreas Uellen
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Eva Bernhart
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Astrid Hammer
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria
| | - Sabine Damm
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Andrea Wintersperger
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Helga Reicher
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Albin Hermetter
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Ernst Malle
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Wolfgang Sattler
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
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Sierant M, Paluch P, Florczak M, Rozanski A, Miksa B. Photosensitive nanocapsules for use in imaging from poly(styrene-co-divinylbenzene) cross-linked with coumarin derivatives. Colloids Surf B Biointerfaces 2013; 111:571-8. [DOI: 10.1016/j.colsurfb.2013.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 06/29/2013] [Accepted: 07/01/2013] [Indexed: 12/23/2022]
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Sezgin E, Levental I, Grzybek M, Schwarzmann G, Mueller V, Honigmann A, Belov VN, Eggeling C, Coskun U, Simons K, Schwille P. Partitioning, diffusion, and ligand binding of raft lipid analogs in model and cellular plasma membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1818:1777-84. [PMID: 22450237 DOI: 10.1016/j.bbamem.2012.03.007] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 03/07/2012] [Accepted: 03/12/2012] [Indexed: 10/28/2022]
Abstract
Several simplified membrane models featuring coexisting liquid disordered (Ld) and ordered (Lo) lipid phases have been developed to mimic the heterogeneous organization of cellular membranes, and thus, aid our understanding of the nature and functional role of ordered lipid-protein nanodomains, termed "rafts". In spite of their greatly reduced complexity, quantitative characterization of local lipid environments using model membranes is not trivial, and the parallels that can be drawn to cellular membranes are not always evident. Similarly, various fluorescently labeled lipid analogs have been used to study membrane organization and function in vitro, although the biological activity of these probes in relation to their native counterparts often remains uncharacterized. This is particularly true for raft-preferring lipids ("raft lipids", e.g. sphingolipids and sterols), whose domain preference is a strict function of their molecular architecture, and is thus susceptible to disruption by fluorescence labeling. Here, we analyze the phase partitioning of a multitude of fluorescent raft lipid analogs in synthetic Giant Unilamellar Vesicles (GUVs) and cell-derived Giant Plasma Membrane Vesicles (GPMVs). We observe complex partitioning behavior dependent on label size, polarity, charge and position, lipid headgroup, and membrane composition. Several of the raft lipid analogs partitioned into the ordered phase in GPMVs, in contrast to fully synthetic GUVs, in which most raft lipid analogs mis-partitioned to the disordered phase. This behavior correlates with the greatly enhanced order difference between coexisting phases in the synthetic system. In addition, not only partitioning, but also ligand binding of the lipids is perturbed upon labeling: while cholera toxin B binds unlabeled GM1 in the Lo phase, it binds fluorescently labeled GMI exclusively in the Ld phase. Fluorescence correlation spectroscopy (FCS) by stimulated emission depletion (STED) nanoscopy on intact cellular plasma membranes consistently reveals a constant level of confined diffusion for raft lipid analogs that vary greatly in their partitioning behavior, suggesting different physicochemical bases for these phenomena.
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Affiliation(s)
- Erdinc Sezgin
- Biophysics/BIOTEC, TU Dresden. Tatzberg 47-51, 01307 Dresden, Germany
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Abe M, Kobayashi T. Imaging local sphingomyelin-rich domains in the plasma membrane using specific probes and advanced microscopy. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:720-6. [PMID: 23860017 DOI: 10.1016/j.bbalip.2013.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 01/28/2023]
Abstract
Sphingomyelin (SM) is one of the major lipids in the mammalian plasma membrane. Multiple lines of evidence suggest that SM plays at least two functional roles in the cell, as a reservoir of lipid second messengers and as a platform for signaling molecules. To understand the molecular organization and dynamics of the SM-rich membrane domains, new approaches have been developed utilizing newly characterized specific SM-binding probes and state-of-the-art microscopy techniques. The toxic protein from the sea anemone, equinatoxin II, has been characterized as a specific probe for SM. The cytolytic protein from the earthworm, lysenin, has also been used as a SM-specific probe for the analysis of the heterogeneity of SM-rich membrane domains. Recently, using a non-toxic form of lysenin, we showed the spatial and temporal localization of SM in the plasma membrane by confocal and super-resolution microscopy. New microscopy techniques have also been introduced by other groups to help visualize membrane lipid domains. Here we review the most recent studies on imaging the SM-rich domains in biological membranes. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
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Affiliation(s)
- Mitsuhiro Abe
- Lipid Biology Laboratory, RIKEN, Wako, Saitama, Japan
| | - Toshihide Kobayashi
- Lipid Biology Laboratory, RIKEN, Wako, Saitama, Japan; INSERM U1060, Université Lyon1, INSA Lyon, Villeurbanne, France.
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57
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Martin ML, Liebisch G, Lehneis S, Schmitz G, Alonso-Sande M, Bestard-Escalas J, Lopez DH, García-Verdugo JM, Soriano-Navarro M, Busquets X, Escribá PV, Barceló-Coblijn G. Sustained activation of sphingomyelin synthase by 2-hydroxyoleic acid induces sphingolipidosis in tumor cells. J Lipid Res 2013; 54:1457-65. [PMID: 23471028 PMCID: PMC3653406 DOI: 10.1194/jlr.m036749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/07/2013] [Indexed: 12/22/2022] Open
Abstract
The mechanism of action of 2-hydroxyoleic acid (2OHOA), a potent antitumor drug, involves the rapid and specific activation of sphingomyelin synthase (SMS), leading to a 4-fold increase in SM mass in tumor cells. In the present study, we investigated the source of the ceramides required to sustain this dramatic increase in SM. Through radioactive and fluorescent labeling, we demonstrated that sphingolipid metabolism was altered by a 24 h exposure to 2OHOA, and we observed a consistent increase in the number of lysosomes and the presence of unidentified storage materials in treated cells. Mass spectroscopy revealed that different sphingolipid classes accumulated in human glioma U118 cells after exposure to 2OHOA, demonstrating a specific effect on C16-, C20-, and C22-containing sphingolipids. Based on these findings, we propose that the demand for ceramides required to sustain the SMS activation (ca. 200-fold higher than the basal level) profoundly modifies both sphingolipid and phospholipid metabolism. As the treatment is prolonged, tumor cells fail to adequately metabolize sphingolipids, leading to a situation resembling sphingolipidosis, whereby cell viability is compromised.
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Affiliation(s)
- Maria Laura Martin
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University Institute for Research into Health Sciences (IUNICS), University of the Balearic Islands, E-07122 Palma, Balearic Islands, Spain
| | - Gerhard Liebisch
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, 93042 Regensburg, Germany; and
| | - Stefan Lehneis
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, 93042 Regensburg, Germany; and
| | - Gerd Schmitz
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, 93042 Regensburg, Germany; and
| | - María Alonso-Sande
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University Institute for Research into Health Sciences (IUNICS), University of the Balearic Islands, E-07122 Palma, Balearic Islands, Spain
| | - Joan Bestard-Escalas
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University Institute for Research into Health Sciences (IUNICS), University of the Balearic Islands, E-07122 Palma, Balearic Islands, Spain
| | - Daniel H. Lopez
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University Institute for Research into Health Sciences (IUNICS), University of the Balearic Islands, E-07122 Palma, Balearic Islands, Spain
| | - José Manuel García-Verdugo
- Laboratorio de Morfología Celular, Unidad Mixta Centre d'Investigació Príncep Felipe-Universitat de València Estudis Generals (CIPF-UVEG), Centro de Investigación Biomédica en Red, Enfermedades Neurodegenerativas (CIBERNED), 46013 Valencia, Spain
| | - Mario Soriano-Navarro
- Laboratorio de Morfología Celular, Unidad Mixta Centre d'Investigació Príncep Felipe-Universitat de València Estudis Generals (CIPF-UVEG), Centro de Investigación Biomédica en Red, Enfermedades Neurodegenerativas (CIBERNED), 46013 Valencia, Spain
| | - Xavier Busquets
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University Institute for Research into Health Sciences (IUNICS), University of the Balearic Islands, E-07122 Palma, Balearic Islands, Spain
| | - Pablo V. Escribá
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University Institute for Research into Health Sciences (IUNICS), University of the Balearic Islands, E-07122 Palma, Balearic Islands, Spain
| | - Gwendolyn Barceló-Coblijn
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University Institute for Research into Health Sciences (IUNICS), University of the Balearic Islands, E-07122 Palma, Balearic Islands, Spain
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58
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59
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D'Auria L, Fenaux M, Aleksandrowicz P, Van Der Smissen P, Chantrain C, Vermylen C, Vikkula M, Courtoy PJ, Tyteca D. Micrometric segregation of fluorescent membrane lipids: relevance for endogenous lipids and biogenesis in erythrocytes. J Lipid Res 2013; 54:1066-76. [PMID: 23322884 DOI: 10.1194/jlr.m034314] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Micrometric membrane lipid segregation is controversial. We addressed this issue in attached erythrocytes and found that fluorescent boron dipyrromethene (BODIPY) analogs of glycosphingolipids (GSLs) [glucosylceramide (BODIPY-GlcCer) and monosialotetrahexosylganglioside (GM1BODIPY)], sphingomyelin (BODIPY-SM), and phosphatidylcholine (BODIPY-PC inserted into the plasma membrane spontaneously gathered into distinct submicrometric domains. GM1BODIPY domains colocalized with endogenous GM1 labeled by cholera toxin. All BODIPY-lipid domains disappeared upon erythrocyte stretching, indicating control by membrane tension. Minor cholesterol depletion suppressed BODIPY-SM and BODIPY-PC but preserved BODIPY-GlcCer domains. Each type of domain exchanged constituents but assumed fixed positions, suggesting self-clustering and anchorage to spectrin. Domains showed differential association with 4.1R versus ankyrin complexes upon antibody patching. BODIPY-lipid domains also responded differentially to uncoupling at 4.1R complexes [protein kinase C (PKC) activation] and ankyrin complexes (in spherocytosis, a membrane fragility disease). These data point to micrometric compartmentation of polar BODIPY-lipids modulated by membrane tension, cholesterol, and differential association to the two nonredundant membrane:spectrin anchorage complexes. Micrometric compartmentation might play a role in erythrocyte membrane deformability and fragility.
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Affiliation(s)
- Ludovic D'Auria
- CELL Unit, Division of Hematology-Oncology, de Duve Institute and Université Catholique de Louvain, Brussels, Belgium
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60
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Thiele C, Papan C, Hoelper D, Kusserow K, Gaebler A, Schoene M, Piotrowitz K, Lohmann D, Spandl J, Stevanovic A, Shevchenko A, Kuerschner L. Tracing fatty acid metabolism by click chemistry. ACS Chem Biol 2012; 7:2004-11. [PMID: 22999348 DOI: 10.1021/cb300414v] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fatty acids are abundant constituents of all biological systems, and their metabolism is important for normal function at all levels of an organism. Aberrations in fatty acid metabolism are associated with pathological states and have become a focus of current research, particularly due to the interest in metabolic overload diseases. Here we present a click-chemistry-based method that allows tracing of fatty acid metabolism in virtually any biological system. It combines high sensitivity with excellent linearity and fast sample turnover. Since it is free of radioactivity, it can be combined with any other modern analysis technology and can be used in high-throughput applications. Using the new method, we provide for the first time an analysis of cellular fatty metabolism with high time resolution and a comprehensive comparison of utilization of a broad spectrum of fatty acids in hepatoma and adipose cell lines.
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Affiliation(s)
- Christoph Thiele
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Cyrus Papan
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse
108, D-01307 Dresden, Germany
| | - Dominik Hoelper
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Kalina Kusserow
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Anne Gaebler
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Mario Schoene
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Kira Piotrowitz
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Daniel Lohmann
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Johanna Spandl
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Ana Stevanovic
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
| | - Andrej Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse
108, D-01307 Dresden, Germany
| | - Lars Kuerschner
- LIMES Life and Medical Sciences
Institute, University of Bonn, Carl-Troll-Strasse
31, D-53115 Bonn, Germany
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Kim R, Lou K, Kraft ML. A new, long-wavelength borondipyrromethene sphingosine for studying sphingolipid dynamics in live cells. J Lipid Res 2012; 54:265-75. [PMID: 23129779 DOI: 10.1194/jlr.d029207] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sphingolipids function as cell membrane components and as signaling molecules that regulate critical cellular processes. To study unacylated and acylated sphingolipids in cells with fluorescence microscopy, the fluorophore in the analog must be located within the sphingoid backbone and not the N-acyl fatty acid side chain. Although such fluorescent sphingosine analogs have been reported, they either require UV excitation or their emission overlaps with that of the most common protein label, green fluorescent protein (GFP). We report the synthesis and use of a new fluorescent sphingolipid analog, borondipyrromethene (BODIPY) 540 sphingosine, which has an excitation maximum at 540 nm and emission that permits its visualization in parallel with GFP. Mammalian cells readily metabolized BODIPY 540 sphingosine to more complex fluorescent sphingolipids, and subsequently degraded these fluorescent sphingolipids via the native sphingolipid catabolism pathway. Visualization of BODIPY 540 fluorescence in parallel with GFP-labeled organelle-specific proteins showed the BODIPY 540 sphingosine metabolites were transported through the secretory pathway and were transiently located within lysosomes, mitochondria, and the nucleus. The reported method for using BODIPY 540 sphingosine to visualize sphingolipids in parallel with GFP-labeled proteins within living cells may permit new insight into sphingolipid transport, metabolism, and signaling.
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Affiliation(s)
- Raehyun Kim
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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63
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Ernst AM, Contreras FX, Thiele C, Wieland F, Brügger B. Mutual recognition of sphingolipid molecular species in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2616-22. [DOI: 10.1016/j.bbamem.2012.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 06/04/2012] [Indexed: 01/11/2023]
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64
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Novel fluorescent ceramide derivatives for probing ceramidase substrate specificity. Bioorg Med Chem 2012; 20:6154-61. [PMID: 22989909 DOI: 10.1016/j.bmc.2012.08.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 07/31/2012] [Accepted: 08/08/2012] [Indexed: 12/21/2022]
Abstract
Ceramidases are key regulators of cell fate. The biochemistry of different ceramidases and of their substrate ceramide appears to be complex, mainly due to specific biophysical characteristics at the water-membrane interface. In the present study, we describe the design and synthesis of a set of fluorescently labeled ceramides as substrates for acid and neutral ceramidases. For the first time we have replaced the commonly used polar NBD-dye with the lipophilic Nile Red (NR) dye. Analysis of kinetic data reveal that although both the dyes do not have any noticeable preference for the substitution at acyl or sphingosine (Sph) part in ceramide towards hydrolysis by acid ceramidase, the ceramides with acyl-substituted NBD and Sph-substituted NR dyes have been found to be a better substrate for neutral ceramidase.
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65
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Patalag LJ, Werz DB. Fluorescent penta- and hexaene fatty acids by a Wittig-Horner/elimination strategy. J Org Chem 2012; 77:5297-304. [PMID: 22616932 DOI: 10.1021/jo300624h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular fluorescent probes have revolutionized biochemical and biophysical studies in the last decades, but with regard to lipids there has been a lack of combining the slim shape of saturated acyl chains with fluorescent properties. Our strategy to pentaene and hexaene fatty acids builds upon commercially available 4-(E)-decenal, which is subjected to a Wittig-Horner reaction after chlorination in α-position. DBU-mediated β-elimination of HCl proceeding the olefination establishes a highly conjugated system to which a salt-free Wittig reaction adds a final double bond leading to a good (Z)-selectivity of 83-86%. The double bond geometry can be optionally isomerized with I(2) to furnish the all-(E)-species. The five conjugated alkene moieties result in a longest-wavelength absorption maximum of about 350 nm. A red-shift to 380 nm was realized by addition of another double bond employing a common Wittig-Horner prolongation sequence. Stokes shifts of about 7300 and 7800 cm(-1), respectively, were observed.
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Affiliation(s)
- Lukas J Patalag
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
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Sato S, Kawamoto J, Sato SB, Watanabe B, Hiratake J, Esaki N, Kurihara T. Occurrence of a bacterial membrane microdomain at the cell division site enriched in phospholipids with polyunsaturated hydrocarbon chains. J Biol Chem 2012; 287:24113-21. [PMID: 22648406 DOI: 10.1074/jbc.m111.318311] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we found that phospholipids containing an eicosapentaenyl group form a novel membrane microdomain at the cell division site of a Gram-negative bacterium, Shewanella livingstonensis Ac10, using chemically synthesized fluorescent probes. The occurrence of membrane microdomains in eukaryotes and prokaryotes has been demonstrated with various imaging tools for phospholipids with different polar headgroups. However, few studies have focused on the hydrocarbon chain-dependent localization of membrane-resident phospholipids in vivo. We previously found that lack of eicosapentaenoic acid (EPA), a polyunsaturated fatty acid found at the sn-2 position of glycerophospholipids, causes a defect in cell division after DNA replication of S. livingstonensis Ac10. Here, we synthesized phospholipid probes labeled with a fluorescent 7-nitro-2,1,3-benzoxadiazol-4-yl (NBD) group to study the localization of EPA-containing phospholipids by fluorescence microscopy. A fluorescent probe in which EPA was bound to the glycerol backbone via an ester bond was found to be unsuitable for imaging because EPA was released from the probe by in vivo hydrolysis. To overcome this problem, we synthesized hydrolysis-resistant ether-type phospholipid probes. Using these probes, we found that the fluorescence localized between two nucleoids at the cell center during cell division when the cells were grown in the presence of the eicosapentaenyl group-containing probe (N-NBD-1-oleoyl-2-eicosapentaenyl-sn-glycero-3-phosphoethanolamine), whereas this localization was not observed with the oleyl group-containing control probe (N-NBD-1-oleoyl-2-oleyl-sn-glycero-3-phosphoethanolamine). Thus, phospholipids containing an eicosapentaenyl group are specifically enriched at the cell division site. Formation of a membrane microdomain enriched in EPA-containing phospholipids at the nucleoid occlusion site probably facilitates cell division.
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Affiliation(s)
- Sho Sato
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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Poppelreuther M, Rudolph B, Du C, Großmann R, Becker M, Thiele C, Ehehalt R, Füllekrug J. The N-terminal region of acyl-CoA synthetase 3 is essential for both the localization on lipid droplets and the function in fatty acid uptake. J Lipid Res 2012; 53:888-900. [PMID: 22357706 PMCID: PMC3329388 DOI: 10.1194/jlr.m024562] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 02/21/2012] [Indexed: 12/19/2022] Open
Abstract
Cytosolic lipid droplets (LDs) are storage organelles for neutral lipids derived from endogenous metabolism. Acyl-CoA synthetase family proteins are essential enzymes in this biosynthetic pathway, contributing activated fatty acids. Fluorescence microscopy showed that ACSL3 is localized to the endoplasmic reticulum (ER) and LDs, with the distribution dependent on the cell type and the supply of fatty acids. The N-terminus of ACSL3 was necessary and sufficient for targeting reporter proteins correctly, as demonstrated by subcellular fractionation and confocal microscopy. The N-terminal region of ACSL3 was also found to be functionally required for the enzyme activity. Selective permeabilization and in silico analysis suggest that ACSL3 assumes a hairpin membrane topology, with the N-terminal hydrophobic amino acids forming an amphipathic helix restricted to the cytosolic leaflet of the ER membrane. ACSL3 was effectively translocated from the ER to nascent LDs when neutral lipid synthesis was stimulated by the external addition of fatty acids. Cellular fatty acid uptake was increased by overexpression and reduced by RNA interference of ACSL3. In conclusion, the structural organization of ACSL3 allows the fast and efficient movement from the ER to emerging LDs. ACSL3 not only esterifies fatty acids with CoA but is also involved in the cellular uptake of fatty acids, presumably indirectly by metabolic trapping. The unique localization of the acyl-CoA synthetase ACSL3 on LDs suggests a function in the local synthesis of lipids.
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Affiliation(s)
- Margarete Poppelreuther
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Germany; and
| | - Berenice Rudolph
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Germany; and
| | - Chen Du
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Germany; and
| | - Regina Großmann
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Germany; and
| | - Melanie Becker
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Germany; and
| | | | - Robert Ehehalt
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Germany; and
| | - Joachim Füllekrug
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Germany; and.
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68
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Kuerschner L, Richter D, Hannibal-Bach HK, Gaebler A, Shevchenko A, Ejsing CS, Thiele C. Exogenous ether lipids predominantly target mitochondria. PLoS One 2012; 7:e31342. [PMID: 22348073 PMCID: PMC3279356 DOI: 10.1371/journal.pone.0031342] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 01/06/2012] [Indexed: 11/18/2022] Open
Abstract
Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high amounts of ether-phosphatidylcholine and ether-phosphatidylethanolamine. Both lipids were specifically labeled using the corresponding lyso-ether lipids, which we established as supreme precursors for lipid tagging. Polyfosine, a fluorescent analogue of the anti-neoplastic ether lipid edelfosine, accumulated to mitochondria and induced morphological changes and cellular apoptosis. These data indicate that edelfosine could exert its pro-apoptotic power by targeting and damaging mitochondria and thereby inducing cellular apoptosis. In general, this study implies an important role of mitochondria in ether lipid metabolism and intracellular ether lipid trafficking.
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Affiliation(s)
- Lars Kuerschner
- Life and Medical Sciences Institute, LIMES, University of Bonn, Bonn, Germany.
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69
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Molecular recognition of a single sphingolipid species by a protein's transmembrane domain. Nature 2012; 481:525-9. [PMID: 22230960 DOI: 10.1038/nature10742] [Citation(s) in RCA: 287] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 11/30/2011] [Indexed: 12/16/2022]
Abstract
Functioning and processing of membrane proteins critically depend on the way their transmembrane segments are embedded in the membrane. Sphingolipids are structural components of membranes and can also act as intracellular second messengers. Not much is known of sphingolipids binding to transmembrane domains (TMDs) of proteins within the hydrophobic bilayer, and how this could affect protein function. Here we show a direct and highly specific interaction of exclusively one sphingomyelin species, SM 18, with the TMD of the COPI machinery protein p24 (ref. 2). Strikingly, the interaction depends on both the headgroup and the backbone of the sphingolipid, and on a signature sequence (VXXTLXXIY) within the TMD. Molecular dynamics simulations show a close interaction of SM 18 with the TMD. We suggest a role of SM 18 in regulating the equilibrium between an inactive monomeric and an active oligomeric state of the p24 protein, which in turn regulates COPI-dependent transport. Bioinformatic analyses predict that the signature sequence represents a conserved sphingolipid-binding cavity in a variety of mammalian membrane proteins. Thus, in addition to a function as second messengers, sphingolipids can act as cofactors to regulate the function of transmembrane proteins. Our discovery of an unprecedented specificity of interaction of a TMD with an individual sphingolipid species adds to our understanding of why biological membranes are assembled from such a large variety of different lipids.
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70
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Abstract
Endosomes along the degradation pathway exhibit a multivesicular appearance and differ in their lipid compositions. Association of proteins to specific membrane lipids and presumably also lipid-lipid interactions contribute to the formation of functional membrane platforms that regulate endosome biogenesis and function. This chapter provides a brief review of the functions of endosomal lipids in the degradation pathway, a discussion of techniques that allow studying lipid-based mechanisms and a selection of step-by-step protocols for in vivo and in vitro methods commonly used to study lipid roles in endocytosis. The techniques described here have been used to elucidate the function of the late endosomal lipid lysobisphosphatidic acid and allow the monitoring of lipid distribution, levels and dynamics, as well as the characterization of lipid-binding partners.
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71
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Digel M, Staffer S, Ehehalt F, Stremmel W, Ehehalt R, Füllekrug J. FATP4 contributes as an enzyme to the basal and insulin-mediated fatty acid uptake of C₂C₁₂ muscle cells. Am J Physiol Endocrinol Metab 2011; 301:E785-96. [PMID: 21750264 DOI: 10.1152/ajpendo.00079.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The function of membrane proteins in long-chain fatty acid transport is controversial. The acyl-CoA synthetase fatty acid transport protein-4 (FATP4) has been suggested to facilitate fatty acid uptake indirectly by its enzymatic activity, or directly by transport across the plasma membrane. Here, we investigated the function of FATP4 in basal and insulin mediated fatty acid uptake in C(2)C(12) muscle cells, a model system relevant for fatty acid metabolism. Stable expression of exogenous FATP4 resulted in a twofold higher fatty acyl-CoA synthetase activity, and cellular uptake of oleate was enhanced similarly. Kinetic analysis demonstrated that FATP4 allowed the cells to reach apparent saturation of fatty acid uptake at a twofold higher level compared with control. Short-term treatment with insulin increased fatty acid uptake in line with previous reports. Surprisingly, insulin increased the acyl-CoA synthetase activity of C(2)C(12) cells within minutes. This effect was sensitive to inhibition of insulin signaling by wortmannin. Affinity purified FATP4 prepared from insulin-treated cells showed an enhanced enzyme activity, suggesting it constitutes a novel target of short-term metabolic regulation by insulin. This offers a new mechanistic explanation for the concomitantly observed enhanced fatty acid uptake. FATP4 was colocalized to the endoplasmic reticulum by double immunofluorescence and subcellular fractionation, clearly distinct from the plasma membrane. Importantly, neither differentiation into myotubes nor insulin treatment changed the localization of FATP4. We conclude that FATP4 functions by its intrinsic enzymatic activity. This is in line with the concept that intracellular metabolism plays a significant role in cellular fatty acid uptake.
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Affiliation(s)
- Margarete Digel
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Heidelberg, Germany
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72
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Abstract
Biological research has always tremendously benefited from the development of key methodology. In fact, it was the advent of microscopy that shaped our understanding of cells as the fundamental units of life. Microscopic techniques are still central to the elucidation of biological units and processes, but equally important are methods that allow access to the dimension of time, to investigate the dynamics of molecular functions and interactions. Here, fluorescence spectroscopy with its sensitivity to access the single-molecule level, and its large temporal resolution, has been opening up fully new perspectives for cell biology. Here we summarize the key fluorescent techniques used to study cellular dynamics, with the focus on lipid and membrane systems.
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73
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Ren W, Liu J, Guo S, Wang E. SERS imaging for label-free detection of the phospholipids distribution in hybrid lipid membrane. Sci China Chem 2011. [DOI: 10.1007/s11426-011-4312-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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74
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High-throughput screening of Australian marine organism extracts for bioactive molecules affecting the cellular storage of neutral lipids. PLoS One 2011; 6:e22868. [PMID: 21857959 PMCID: PMC3152550 DOI: 10.1371/journal.pone.0022868] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 07/08/2011] [Indexed: 12/13/2022] Open
Abstract
Mammalian cells store excess fatty acids as neutral lipids in specialised organelles called lipid droplets (LDs). Using a simple cell-based assay and open-source software we established a high throughput screen for LD formation in A431 cells in order to identify small bioactive molecules affecting lipid storage. Screening an n-butanol extract library from Australian marine organisms we identified 114 extracts that produced either an increase or a decrease in LD formation in fatty acid-treated A431 cells with varying degrees of cytotoxicity. We selected for further analysis a non-cytotoxic extract derived from the genus Spongia (Heterofibria). Solvent partitioning, HPLC fractionation and spectroscopic analysis (NMR, MS) identified a family of related molecules within this extract with unique structural features, a subset of which reduced LD formation. We selected one of these molecules, heterofibrin A1, for more detailed cellular analysis. Inhibition of LD biogenesis by heterofibrin A1 was observed in both A431 cells and AML12 hepatocytes. The activity of heterofibrin A1 was dose dependent with 20 µM inhibiting LD formation and triglyceride accumulation by ∼50% in the presence of 50 µM oleic acid. Using a fluorescent fatty acid analogue we found that heterofibrin A1 significantly reduces the intracellular accumulation of fatty acids and results in the formation of distinct fatty acid metabolites in both cultured cells and in embryos of the zebrafish Danio rerio. In summary we have shown using readily accessible software and a relatively simple assay system that we can identify and isolate bioactive molecules from marine extracts, which affect the formation of LDs and the metabolism of fatty acids both in vitro and in vivo.
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75
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Zhang X, Ye J, Wang S, Gong W, Lin Y, Ning G. Heterocyclic Radical Mediated Synthesis and Fluorescence Properties of Conjugated Polyene Ketones. Org Lett 2011; 13:3608-11. [DOI: 10.1021/ol201207b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Xiangdong Zhang
- State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China, and Department of Chemistry, Queen’s University, Kingston, Ontario, K7L 3N6, Canada
| | - Junwei Ye
- State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China, and Department of Chemistry, Queen’s University, Kingston, Ontario, K7L 3N6, Canada
| | - Suning Wang
- State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China, and Department of Chemistry, Queen’s University, Kingston, Ontario, K7L 3N6, Canada
| | - Weitao Gong
- State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China, and Department of Chemistry, Queen’s University, Kingston, Ontario, K7L 3N6, Canada
| | - Yuan Lin
- State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China, and Department of Chemistry, Queen’s University, Kingston, Ontario, K7L 3N6, Canada
| | - Guiling Ning
- State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China, and Department of Chemistry, Queen’s University, Kingston, Ontario, K7L 3N6, Canada
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76
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Contreras FX, Ernst AM, Wieland F, Brügger B. Specificity of intramembrane protein-lipid interactions. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a004705. [PMID: 21536707 DOI: 10.1101/cshperspect.a004705] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Our concept of biological membranes has markedly changed, from the fluid mosaic model to the current model that lipids and proteins have the ability to separate into microdomains, differing in their protein and lipid compositions. Since the breakthrough in crystallizing membrane proteins, the most powerful method to define lipid-binding sites on proteins has been X-ray and electron crystallography. More recently, chemical biology approaches have been developed to analyze protein-lipid interactions. Such methods have the advantage of providing highly specific cellular probes. With the advent of novel tools to study functions of individual lipid species in membranes together with structural analysis and simulations at the atomistic resolution, a growing number of specific protein-lipid complexes are defined and their functions explored. In the present article, we discuss the various modes of intramembrane protein-lipid interactions in cellular membranes, including examples for both annular and nonannular bound lipids. Furthermore, we will discuss possible functional roles of such specific protein-lipid interactions as well as roles of lipids as chaperones in protein folding and transport.
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77
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Melser S, Molino D, Batailler B, Peypelut M, Laloi M, Wattelet-Boyer V, Bellec Y, Faure JD, Moreau P. Links between lipid homeostasis, organelle morphodynamics and protein trafficking in eukaryotic and plant secretory pathways. PLANT CELL REPORTS 2011; 30:177-193. [PMID: 21120657 DOI: 10.1007/s00299-010-0954-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 11/15/2010] [Indexed: 05/30/2023]
Abstract
The role of lipids as molecular actors of protein transport and organelle morphology in plant cells has progressed over the last years through pharmacological and genetic investigations. The manuscript is reviewing the roles of various lipid families in membrane dynamics and trafficking in eukaryotic cells, and summarizes some of the related physicochemical properties of the lipids involved. The article also focuses on the specific requirements of the sphingolipid glucosylceramide (GlcCer) in Golgi morphology and protein transport through the plant secretory pathway. The use of a specific inhibitor of plant glucosylceramide synthase and selected Arabidopsis thaliana RNAi lines stably expressing several markers of the plant secretory pathway, establishes specific steps sensitive to GlcCer biosynthesis. Collectively, data of the literature demonstrate the existence of links between protein trafficking, organelle morphology, and lipid metabolism/homeostasis in eukaryotic cells including plant cells.
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Affiliation(s)
- Su Melser
- Laboratoire de Biogenèse Membranaire, UMR 5200 Université Bordeaux 2-CNRS, Université Bordeaux 2, case 92, 146 rue Léo-Saignat, 33076 Bordeaux, France.
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78
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Smyk B, Wieczorek P, Zadernowski R. A method of concentration estimation of trienes, tetraenes, and pentaenes in evening primrose oil. EUR J LIPID SCI TECH 2011. [DOI: 10.1002/ejlt.201000418] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Bogdan Smyk
- Chair of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Piotr Wieczorek
- Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Ryszard Zadernowski
- Chair of Food Plant Chemistry and Processing, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
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79
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Reich A, Schwudke D, Meurer M, Lehmann B, Shevchenko A. Lipidome of narrow-band ultraviolet B irradiated keratinocytes shows apoptotic hallmarks. Exp Dermatol 2011; 19:e103-10. [PMID: 19845761 DOI: 10.1111/j.1600-0625.2009.01000.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND UV light triggers a variety of biological responses in irradiated keratinocytes that might be associated with global perturbation of their lipidome. However, lipids that are specifically affected and the exact molecular mechanisms involved remain poorly understood. OBJECTIVES To characterize time-dependent changes of the lipidome of cultured keratinocytes induced by narrow-band ultraviolet B (NB-UVB) irradiation. METHODS Immortalized human keratinocytes (HaCaT) were cultured under standard conditions, irradiated with NB-UVB light (311 nm) at 400 and 800 mJ/cm(2) and collected 1, 2, 3, 6, 12 and 24 h later for lipid extraction. Lipid extracts were separated on silica plates in chloroform/ethanol/water/triethylamine (35:40:9:35) and in n-hexane/ethylacetate (5:1) followed by quantitative shotgun lipidomics analysis. RESULTS Irradiation with 800 mJ/cm(2) of NB-UVB altered morphology and lipidome composition of HaCaT cells. Ceramide content increased two-fold 6- and 12-h postirradiation with 800 mJ/cm(2), followed by threefold increase in triacylglycerols (TAGs) that peaked at 24 h. In addition, we observed marked increase of various phosphatidylcholine and phosphatidylethanolamine ethers, whereas phosphatidylcholine-species with short-chain fatty acid moieties decreased. The abundance of other lipid species was altered to lesser extent or remained unchanged. CONCLUSIONS NB-UVB affected the cellular lipidome of keratinocytes in strictly apoptosis-specific manner.
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Affiliation(s)
- Adam Reich
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland.
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80
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Ohno Y, Yamada S, Sugiura T, Ohira Y, Yoshioka T, Goto K. Possible Role of NF-ĸB Signals in Heat Stress-Associated Increase in Protein Content of Cultured C2C12 Cells. Cells Tissues Organs 2011; 194:363-70. [DOI: 10.1159/000323324] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2010] [Indexed: 12/31/2022] Open
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81
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Carvalho M, Schwudke D, Sampaio JL, Palm W, Riezman I, Dey G, Gupta GD, Mayor S, Riezman H, Shevchenko A, Kurzchalia TV, Eaton S. Survival strategies of a sterol auxotroph. Development 2010; 137:3675-85. [PMID: 20940226 DOI: 10.1242/dev.044560] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The high sterol concentration in eukaryotic cell membranes is thought to influence membrane properties such as permeability, fluidity and microdomain formation. Drosophila cannot synthesize sterols, but do require them for development. Does this simply reflect a requirement for sterols in steroid hormone biosynthesis, or is bulk membrane sterol also essential in Drosophila? If the latter is true, how do they survive fluctuations in sterol availability and maintain membrane homeostasis? Here, we show that Drosophila require both bulk membrane sterol and steroid hormones in order to complete adult development. When sterol availability is restricted, Drosophila larvae modulate their growth to maintain membrane sterol levels within tight limits. When dietary sterol drops below a minimal threshold, larvae arrest growth and development in a reversible manner. Strikingly, membrane sterol levels in arrested larvae are dramatically reduced (dropping sixfold on average) in most tissues except the nervous system. Thus, sterols are dispensable for maintaining the basic membrane biophysical properties required for cell viability; these functions can be performed by non-sterol lipids when sterols are unavailable. However, bulk membrane sterol is likely to have essential functions in specific tissues during development. In tissues in which sterol levels drop, the overall level of sphingolipids increases and the proportion of different sphingolipid variants is altered. These changes allow survival, but not growth, when membrane sterol levels are low. This relationship between sterols and sphingolipids could be an ancient and conserved principle of membrane homeostasis.
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Affiliation(s)
- Maria Carvalho
- Max-Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse-108, 01307 Dresden, Germany
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82
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Hornillos V, Tormo L, Amat-Guerri F, Acuña AU. Synthesis and spectral properties of fluorescent linear alkylphosphocholines labeled with all-(E)-1,6-diphenyl-1,3,5-hexatriene. J Photochem Photobiol A Chem 2010. [DOI: 10.1016/j.jphotochem.2010.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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83
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Le TT, Yue S, Cheng JX. Shedding new light on lipid biology with coherent anti-Stokes Raman scattering microscopy. J Lipid Res 2010; 51:3091-102. [PMID: 20713649 PMCID: PMC2952550 DOI: 10.1194/jlr.r008730] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 08/16/2010] [Indexed: 12/31/2022] Open
Abstract
Despite the ubiquitous roles of lipids in biology, the detection of lipids has relied on invasive techniques, population measurements, or nonspecific labeling. Such difficulties can be circumvented by a label-free imaging technique known as coherent anti-Stokes Raman (CARS) microscopy, which is capable of chemically selective, highly sensitive, and high-speed imaging of lipid-rich structures with submicron three-dimensional spatial resolution. We review the broad applications of CARS microscopy to studies of lipid biology in cell cultures, tissue biopsies, and model organisms. Recent technical advances, limitations of the technique, and perspectives are discussed.
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Affiliation(s)
- Thuc T. Le
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
| | - Shuhua Yue
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
- Department of Chemistry, Purdue University, West Lafayette, IN 47907
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84
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Abstract
Tracking fluorescent lipids in cellular membranes has been applied for decades to shed light on membrane trafficking, sorting, endocytosis and exocytosis, viral entry, and to understand the functional relevance of membrane heterogeneity, phase separation and lipid rafts. However, fluorescent probes may display different organizing behaviour from their corresponding endogenous lipids. A full characterization of these probes is therefore required for proper interpretation of fluorescence microscopy data in complex membrane systems. Model membrane studies provide essential clues that guide us to design and interpret our experiments, help us to avoid pitfalls and resolve artefacts in complex cellular environments. In the present issue of the Biochemical Journal, Juhasz, Davis and Sharom demonstrate the importance of testing lipid probes systematically in heterogeneous model membranes of specific composition and well-defined thermodynamic properties. The phase-partitioning behaviour of fluorescent probes, alone and/or in combination, cannot simply be assumed, but has to be fully characterized.
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85
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Yang HJ, Ishizaki I, Sanada N, Zaima N, Sugiura Y, Yao I, Ikegami K, Setou M. Detection of characteristic distributions of phospholipid head groups and fatty acids on neurite surface by time-of-flight secondary ion mass spectrometry. Med Mol Morphol 2010; 43:158-64. [PMID: 20857264 DOI: 10.1007/s00795-009-0487-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 11/26/2009] [Indexed: 12/27/2022]
Abstract
Neurons have a large surface because of their long and thin neurites. This surface is composed of a lipid bilayer. Lipids have not been actively investigated so far because of some technical difficulties, although evidence from cell biology is emerging that lipids contain valuable information about their roles in the central nervous system. Recent progress in techniques, e.g., mass spectrometry, opens a new epoch of lipid research. We show herein the characteristic localization of phospholipid components in neurites by means of time-of-flight secondary ion mass spectrometry. We used explant cultures of mouse superior cervical ganglia, which are widely used by neurite investigation research. In a positive-ion detection mode, phospholipid head group molecules were predominantly detected. The ions of m/z 206.1 [phosphocholine, a common component of phosphatidylcholine (PC) and sphingomyelin (SM)] were evenly distributed throughout the neurites, whereas the ions of m/z 224.1, 246.1 (glycerophosphocholine, a part of PC, but not SM) showed relatively strong intensity on neurites adjacent to soma. In a negative-ion detection mode, fatty acids such as oleic and palmitic acids were mainly detected, showing high intensity on neurites adjacent to soma. Our results suggest that lipid components on the neuritic surface show characteristic distributions depending on neurite region.
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Affiliation(s)
- Hyun-Jeong Yang
- Department of Bioscience and Biotechnology, Tokyo Institute of Technology, Kanagawa, Japan
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86
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Horobin RW, Stockert JC. Uptake and localization mechanisms of fluorescent and colored lipid probes. 1. Physicochemistry of probe uptake and localization, and the use of QSAR models for selectivity prediction. Biotech Histochem 2010; 86:379-93. [DOI: 10.3109/10520295.2010.515489] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- RW Horobin
- School of Life Sciences, The University of Glasgow, University Avenue,
Glasgow G12 8QQ, Scotland, UK
| | - JC Stockert
- Department of Biology, Faculty of Sciences, Autonomous University of Madrid,
Cantoblanco, Madrid 28049
- Center for Biological Research, High Council of Scientific Research,
Madrid 28040, Spain
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87
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Abstract
Although lipids are biomolecules with seemingly simple chemical structures, the molecular composition of the cellular lipidome is complex and, currently, poorly understood. The exact mechanisms of how compositional complexity affects cell homeostasis and its regulation also remain unclear. This emerging field is developing sensitive mass spectrometry technologies for the quantitative characterization of the lipidome. Here, we argue that lipidomics will become an essential tool kit in cell and developmental biology, molecular medicine and nutrition.
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88
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Stockert JC, Abasolo MI, Blázquez-Castro A, Horobin RW, Revilla M, Lombardo DM. Selective labeling of lipid droplets in aldehyde fixed cell monolayers by lipophilic fluorochromes. Biotech Histochem 2010; 85:277-83. [DOI: 10.3109/10520290903196183] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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89
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McIntosh AL, Huang H, Atshaves BP, Wellberg E, Kuklev DV, Smith WL, Kier AB, Schroeder F. Fluorescent n-3 and n-6 very long chain polyunsaturated fatty acids: three-photon imaging in living cells expressing liver fatty acid-binding protein. J Biol Chem 2010; 285:18693-708. [PMID: 20382741 PMCID: PMC2881794 DOI: 10.1074/jbc.m109.079897] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 03/10/2010] [Indexed: 01/24/2023] Open
Abstract
Despite the considerable beneficial effects of n-3 and n-6 very long chain polyunsaturated fatty acids (VLC-PUFAs), very little is known about the factors that regulate their uptake and intracellular distribution in living cells. This issue was addressed in cells expressing liver-type fatty acid-binding protein (L-FABP) by real time multiphoton laser scanning microscopy of novel fluorescent VLC-PUFAs containing a conjugated tetraene fluorophore near the carboxyl group and natural methylene-interrupted n-3 or n-6 grouping. The fluorescent VLC-PUFAs mimicked many properties of their native nonfluorescent counterparts, including uptake, distribution, and metabolism in living cells. The unesterified fluorescent VLC-PUFAs distributed either equally in nuclei versus cytoplasm (22-carbon n-3 VLC-PUFA) or preferentially to cytoplasm (20-carbon n-3 and n-6 VLC-PUFAs). L-FABP bound fluorescent VLC-PUFA with affinity and specificity similar to their nonfluorescent natural counterparts. Regarding n-3 and n-6 VLC-PUFA, L-FABP expression enhanced uptake into the cell and cytoplasm, selectively altered the pattern of fluorescent n-6 and n-3 VLC-PUFA distribution in cytoplasm versus nuclei, and preferentially distributed fluorescent VLC-PUFA into nucleoplasm versus nuclear envelope, especially for the 22-carbon n-3 VLC-PUFA, correlating with its high binding by L-FABP. Multiphoton laser scanning microscopy data showed for the first time VLC-PUFA in nuclei of living cells and suggested a model, whereby L-FABP facilitated VLC-PUFA targeting to nuclei by enhancing VLC-PUFA uptake and distribution into the cytoplasm and nucleoplasm.
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Affiliation(s)
| | - Huan Huang
- From the Departments of Physiology and Pharmacology and
| | - Barbara P. Atshaves
- the Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, and
| | | | - Dmitry V. Kuklev
- the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - William L. Smith
- the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Ann B. Kier
- Pathobiology, Texas A & M University, Texas Veterinary Medical Center, College Station, Texas 77843-4466
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90
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Sinkeldam RW, Greco NJ, Tor Y. Fluorescent analogs of biomolecular building blocks: design, properties, and applications. Chem Rev 2010; 110:2579-619. [PMID: 20205430 PMCID: PMC2868948 DOI: 10.1021/cr900301e] [Citation(s) in RCA: 665] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Renatus W. Sinkeldam
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, La Jolla, California 92093-0358
| | | | - Yitzhak Tor
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, La Jolla, California 92093-0358
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91
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Lipid droplets lighting up: insights from live microscopy. FEBS Lett 2010; 584:2168-75. [PMID: 20347811 DOI: 10.1016/j.febslet.2010.03.035] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 03/19/2010] [Accepted: 03/22/2010] [Indexed: 11/19/2022]
Abstract
Lipid droplets emerge as important intracellular organelles relevant for lipid homeostasis and the pathophysiology of metabolic diseases. Here, we present a personal view on the current knowledge about the biogenesis of mammalian cytoplasmic lipid droplets, with a focus on microscopy and especially live imaging. We also discuss difficulties related to the lipid droplet proteome, contentious views on lipid droplet growth, and last but not least the evidence for the heterogeneity of lipid droplets within a single cell. We conclude with an outline of the most important future challenges.
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92
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Honsho M, Asaoku S, Fujiki Y. Posttranslational regulation of fatty acyl-CoA reductase 1, Far1, controls ether glycerophospholipid synthesis. J Biol Chem 2010; 285:8537-42. [PMID: 20071337 DOI: 10.1074/jbc.m109.083311] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasmalogens are a major subclass of ethanolamine and choline glycerophospholipids in which a long chain fatty alcohol is attached at the sn-1 position through a vinyl ether bond. This ether-linked alkyl bond is formed in peroxisomes by replacement of a fatty acyl chain in the intermediate 1-acyl-dihydroxyacetone phosphate with a fatty alcohol in a reaction catalyzed by alkyl dihydroxyacetone phosphate synthase. Here, we demonstrate that the enzyme fatty acyl-CoA reductase 1 (Far1) supplies the fatty alcohols used in the formation of ether-linked alkyl bonds. Far1 activity is elevated in plasmalogen-deficient cells, and conversely, the levels of this enzyme are restored to normal upon plasmalogen supplementation. Down-regulation of Far1 activity in response to plasmalogens is achieved by increasing the rate of degradation of peroxisomal Far1 protein. Supplementation of normal cells with ethanolamine and 1-O-hexadecylglycerol, which are intermediates in plasmalogen biosynthesis, accelerates degradation of Far1. Taken together, our results indicate that ether lipid biosynthesis in mammalian cells is regulated by a negative feedback mechanism that senses cellular plasmalogen levels and appropriately increases or decreases Far1.
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Affiliation(s)
- Masanori Honsho
- Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
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93
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Haberkant P, van Meer G. Protein-lipid interactions: paparazzi hunting for snap-shots. Biol Chem 2009; 390:795-803. [PMID: 19426134 DOI: 10.1515/bc.2009.074] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Photoactivatable groups meeting the criterion of minimal perturbance allow the investigation of interactions in biological samples. Here, we review the application of photoactivatable groups in lipids enabling the study of protein-lipid interactions in (biological) membranes. The chemistry of various photoactivatable groups is summarized and the specificity of the interactions detected is discussed. The recent introduction of 'click chemistry' in photocrosslinking of membrane proteins by photo-activatable lipids opens new possibilities for the analysis of crosslinked products and will help to close the gap between proteomics and lipidomics.
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Affiliation(s)
- Per Haberkant
- Membrane Enzymology, Bijvoet Center and Institute of Biomembranes, Utrecht University, NL-3584 CH Utrecht, The Netherlands.
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94
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Novotný J, Pospechová K, Hrabálek A, Cáp R, Vávrová K. Synthesis of fluorescent C24-ceramide: evidence for acyl chain length dependent differences in penetration of exogenous NBD-ceramides into human skin. Bioorg Med Chem Lett 2009; 19:6975-7. [PMID: 19879139 DOI: 10.1016/j.bmcl.2009.10.047] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 10/09/2009] [Accepted: 10/10/2009] [Indexed: 11/18/2022]
Abstract
Topical skin lipid supplementation may provide opportunities for controlling ceramide (Cer) deficiency in skin diseases such as atopic dermatitis or psoriasis. Here we describe the synthesis of a long-chain 7-nitrobenzo[c][1,2,5]oxadiazol-4-yl (NBD)-labeled Cer and its different penetration through human skin compared to widely used short-chain fluorescent Cer tools.
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Affiliation(s)
- Jakub Novotný
- Centre for New Antivirals and Antineoplastics, Department of Inorganic and Organic Chemistry, Charles University in Prague, Faculty of Pharmacy, Hradec Králové, Czech Republic
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95
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Smyk B, Amarowicz R, Szabelski M, Gryczynski I, Gryczynski Z. Steady-state and time-resolved fluorescence studies of stripped Borage oil. Anal Chim Acta 2009; 646:85-9. [DOI: 10.1016/j.aca.2009.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 05/06/2009] [Indexed: 11/30/2022]
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96
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Sorting of lipids and proteins in membrane curvature gradients. Biophys J 2009; 96:2676-88. [PMID: 19348750 DOI: 10.1016/j.bpj.2008.11.067] [Citation(s) in RCA: 229] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 11/11/2008] [Accepted: 11/24/2008] [Indexed: 11/20/2022] Open
Abstract
The sorting of lipids and proteins in cellular trafficking pathways is a process of central importance in maintaining compartmentalization in eukaryotic cells. However, the mechanisms behind these sorting phenomena are currently far from being understood. Among several mechanistic suggestions, membrane curvature has been invoked as a means to segregate lipids and proteins in cellular sorting centers. To assess this hypothesis, we investigate the sorting of lipid analog dye trace components between highly curved tubular membranes and essentially flat membranes of giant unilamellar vesicles. Our experimental findings indicate that intracellular lipid sorting, contrary to frequent assumptions, is unlikely to occur by lipids fitting into membrane regions of appropriate curvature. This observation is explained in the framework of statistical mechanical lattice models that show that entropy, rather than curvature energy, dominates lipid distribution in the absence of strongly preferential lateral intermolecular interactions. Combined with previous findings of curvature induced phase segregation, we conclude that lipid cooperativity is required to enable efficient sorting. In contrast to lipid analog dyes, the peripheral membrane binding protein Cholera toxin subunit B is effectively curvature-sorted. The sorting of Cholera toxin subunit B is rationalized by statistical models. We discuss the implications of our findings for intracellular sorting mechanisms.
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97
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Quantitative electron microscopy shows uniform incorporation of triglycerides into existing lipid droplets. Histochem Cell Biol 2009; 132:281-91. [DOI: 10.1007/s00418-009-0615-z] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2009] [Indexed: 12/14/2022]
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98
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Membrane lipid domains and rafts: current applications of fluorescence lifetime spectroscopy and imaging. Chem Phys Lipids 2009; 157:61-77. [DOI: 10.1016/j.chemphyslip.2008.07.011] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 07/24/2008] [Indexed: 11/30/2022]
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99
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Grimard V, Massier J, Richter D, Schwudke D, Kalaidzidis Y, Fava E, Hermetter A, Thiele C. siRNA screening reveals JNK2 as an evolutionary conserved regulator of triglyceride homeostasis. J Lipid Res 2008; 49:2427-40. [DOI: 10.1194/jlr.m800168-jlr200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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100
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Cholesterol regulation of rab-mediated sphingolipid endocytosis. Glycoconj J 2008; 26:705-10. [PMID: 18841464 DOI: 10.1007/s10719-008-9191-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 09/05/2008] [Accepted: 09/08/2008] [Indexed: 12/21/2022]
Abstract
Despite a tight regulation of its intracellular content, cholesterol is found accumulated in pathological conditions such as sphingolipidosis as well as after cell treatment with drugs like hydrophobic amines. Furthermore, cellular cholesterol increases when cultured cells approach confluence. Under these conditions, the endocytic pathways of plasma membrane sphingolipids are differently affected. In this short review, we will summarize recent results from our laboratory as well as those of other groups, indicating that the intracellular accumulation of cholesterol inhibits the dissociation of rab GTPases from the target membranes, causing the alteration of rab-mediated membrane traffic.
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