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A hybrid mathematical modeling approach of the metabolic fate of a fluorescent sphingolipid analogue to predict cancer chemosensitivity. Comput Biol Med 2018; 97:8-20. [DOI: 10.1016/j.compbiomed.2018.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/10/2018] [Accepted: 04/12/2018] [Indexed: 01/25/2023]
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2
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Volpert G, Ben-Dor S, Tarcic O, Duan J, Saada A, Merrill AH, Pewzner-Jung Y, Futerman AH. Oxidative stress elicited by modifying the ceramide acyl chain length reduces the rate of clathrin-mediated endocytosis. J Cell Sci 2017; 130:1486-1493. [PMID: 28280117 DOI: 10.1242/jcs.199968] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/28/2017] [Indexed: 12/11/2022] Open
Abstract
Sphingolipids modulate clathrin-mediated endocytosis (CME) by altering the biophysical properties of membranes. We now examine CME in astrocytes cultured from ceramide synthase 2 (CerS2) null mice, which have an altered sphingolipid acyl chain composition. The rate of endocytosis of low-density lipoprotein and transferrin, which are internalized via CME, was reduced in CerS2 null astrocytes, although the rate of caveolin-mediated endocytosis was unaltered. Levels of clathrin heavy chain were increased, which was due to decreased levels of Hsc70 (also known as HSPA8), a protein involved in clathrin uncoating. Hsc70 levels were decreased because of lower levels of binding of Sp1 to position -68 in the Hsc70 promoter. Levels of Sp1 were downregulated due to oxidative stress, which was elevated fourfold in CerS2 null astrocytes. Furthermore, induction of oxidative stress in wild-type astrocytes decreased the rate of CME, whereas amelioration of oxidative stress in CerS2 null astrocytes reversed the decrease. Our data are consistent with the notion that sphingolipids not only change membrane biophysical properties but also that changes in their composition can result in downstream effects that indirectly impinge upon a number of cellular pathways, such as CME.
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Affiliation(s)
- Giora Volpert
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shifra Ben-Dor
- Department of Biological Services, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ohad Tarcic
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jingjing Duan
- School of Biology and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA
| | - Ann Saada
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Hospital, Jerusalem 91120, Israel.,The Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Hospital, Jerusalem 91120, Israel
| | - Alfred H Merrill
- School of Biology and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA
| | - Yael Pewzner-Jung
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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3
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Dauner M, Batroff E, Bachmann V, Hauck CR, Wittmann V. Synthetic Glycosphingolipids for Live-Cell Labeling. Bioconjug Chem 2016; 27:1624-37. [PMID: 27253729 DOI: 10.1021/acs.bioconjchem.6b00177] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glycosphingolipids are an important component of cell membranes that are involved in many biological processes. Fluorescently labeled glycosphingolipids are frequently used to gain insight into their localization. However, the attachment of a fluorophore to the glycan part or-more commonly-to the lipid part of glycosphingolipids is known to alter the biophysical properties and can perturb the biological function of the probe. Presented here is the synthesis of novel glycosphingolipid probes with mono- and disaccharide head groups and ceramide moieties containing fatty acids of varying chain length (C4 to C20). These glycosphingolipids bear an azide or an alkyne group as chemical reporter to which a fluorophore can be attached through a bioorthogonal ligation reaction. The fluorescent tag and any linker connected to it can be chosen in a flexible manner. We demonstrate the suitability of the probes by selective visualization of the plasma membrane of living cells by confocal microscopy techniques. Whereas the derivatives with the shorter fatty acids can be directly applied to HEK 293T cells, the hydrophobic glycosphingolipids with longer fatty acids can be delivered to cells using fusogenic liposomes.
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Affiliation(s)
- Martin Dauner
- Department of Chemistry and ‡Department of Biology, Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz , 78457 Konstanz, Germany
| | - Ellen Batroff
- Department of Chemistry and ‡Department of Biology, Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz , 78457 Konstanz, Germany
| | - Verena Bachmann
- Department of Chemistry and ‡Department of Biology, Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz , 78457 Konstanz, Germany
| | - Christof R Hauck
- Department of Chemistry and ‡Department of Biology, Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz , 78457 Konstanz, Germany
| | - Valentin Wittmann
- Department of Chemistry and ‡Department of Biology, Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz , 78457 Konstanz, Germany
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4
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Ilina P, Partti S, Niklander J, Ruponen M, Lou YR, Yliperttula M. Effect of differentiation on endocytic profiles of endothelial and epithelial cell culture models. Exp Cell Res 2015; 332:89-101. [DOI: 10.1016/j.yexcr.2015.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 01/07/2015] [Accepted: 01/08/2015] [Indexed: 12/31/2022]
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5
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Yin X, Murphy SJ, Wilkes MC, Ji Y, Leof EB. Retromer maintains basolateral distribution of the type II TGF-β receptor via the recycling endosome. Mol Biol Cell 2013; 24:2285-98. [PMID: 23720763 PMCID: PMC3708733 DOI: 10.1091/mbc.e13-02-0093] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
After basolateral (BL) cell surface delivery, retromer promotes type II TGF-β receptor exit and recycling to the BL plasma membrane. In the absence of retromer, however, type II receptors aberrantly sort and are mislocalized such that both BL and apical expression is observed independent of the Rab11-positive apical recycling endosome. Transforming growth factor β (TGF-β) is critical for the development and maintenance of epithelial structures. Because receptor localization and trafficking affect the cellular and organismal response to TGF-β, the present study was designed to address how such homeostatic control is regulated. To that end, we identify a new role for the mammalian retromer complex in maintaining basolateral plasma membrane expression of the type II TGF-β receptor (TβRII). Retromer and TβRII associate in the presence or absence of TGF-β ligand. After retromer knockdown, although TβRII internalization and trafficking to a Rab5-positive compartment occur as in wild-type cells, receptor recycling is inhibited. This results in TβRII mislocalization from the basolateral to both the basolateral and apical plasma membranes independent of Golgi transit and the Rab11-positive apical recycling endosome. The data support a model in which, after initial basolateral TβRII delivery, steady-state polarized TβRII expression is maintained by retromer/TβRII binding and delivery to the common recycling endosome.
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Affiliation(s)
- Xueqian Yin
- Thoracic Disease Research Unit, Departments of Biochemistry/Molecular Biology and Medicine, Mayo Clinic Cancer Center, Rochester, MN 55905, USA
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Bhattacharyya S, Singh RD, Pagano R, Robertson JD, Bhattacharya R, Mukherjee P. Switching the targeting pathways of a therapeutic antibody by nanodesign. Angew Chem Int Ed Engl 2012; 51:1563-7. [PMID: 22135077 PMCID: PMC3324088 DOI: 10.1002/anie.201105432] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 11/09/2011] [Indexed: 12/19/2022]
Affiliation(s)
- Sanjib Bhattacharyya
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN 55905
| | - Raman Deep Singh
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN 55905
- Thorasic Disease Research Unit, College of Medicine, Mayo Clinic, Rochester, MN 55905
| | - Richard Pagano
- Thorasic Disease Research Unit, College of Medicine, Mayo Clinic, Rochester, MN 55905
| | - J. David Robertson
- Department of Chemistry and University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211
| | - Resham Bhattacharya
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN 55905
| | - Priyabrata Mukherjee
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, MN 55905
- Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, MN 55905
- Cancer Center, College of Medicine, Mayo Clinic, Rochester, MN 55905
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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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Bhattacharyya S, Singh RD, Pagano R, Robertson JD, Bhattacharya R, Mukherjee P. Switching the Targeting Pathways of a Therapeutic Antibody by Nanodesign. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201105432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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de Juan-Sanz J, Zafra F, López-Corcuera B, Aragón C. Endocytosis of the neuronal glycine transporter GLYT2: role of membrane rafts and protein kinase C-dependent ubiquitination. Traffic 2011; 12:1850-67. [PMID: 21910806 DOI: 10.1111/j.1600-0854.2011.01278.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glycinergic neurotransmission is terminated by sodium- and chloride-dependent plasma membrane transporters. The neuronal glycine transporter 2 (GLYT2) supplies the terminal with substrate to refill synaptic vesicles containing glycine. This crucial process is defective in human hyperekplexia, a condition that can be caused by mutations in GLYT2. Inhibitory glycinergic neurotransmission is modulated by the GLYT2 exocytosis/endocytosis equilibrium, although the mechanisms underlying the turnover of this transporter remain elusive. We studied GLYT2 internalization pathways and the role of ubiquitination and membrane raft association of the transporter in its endocytosis. Using pharmacological tools, dominant-negative mutants and small-interfering RNAs, we show that the clathrin-mediated pathway is the primary mechanism for constitutive and regulated GLYT2 endocytosis in heterologous cells and neurons. We show that GLYT2 is constitutively internalized from cell surface lipid rafts, remaining associated with rafts in subcellular recycling structures. Protein kinase C (PKC) negatively modulates GLYT2 via rapid and dynamic redistribution of GLYT2 from raft to non-raft membrane subdomains and increasing ubiquitinated GLYT2 endocytosis. This biphasic mechanism is a versatile means to modulate GLYT2 behavior and hence, inhibitory glycinergic neurotransmission. These findings may reveal new therapeutic targets to address glycinergic pathologies associated with alterations in GLYT2 trafficking.
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Affiliation(s)
- Jaime de Juan-Sanz
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Madrid, Spain
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Aoki S, Thomas A, Decaffmeyer M, Brasseur R, Epand RM. The role of proline in the membrane re-entrant helix of caveolin-1. J Biol Chem 2010; 285:33371-33380. [PMID: 20729193 DOI: 10.1074/jbc.m110.153569] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Caveolin-1 has a segment of hydrophobic amino acids comprising approximately residues 103-122. We have performed an in silico analysis of the conformational preference of this segment of caveolin-1 using PepLook. We find that there is one main group of stable conformations corresponding to a hydrophobic U bent model that would not traverse the membrane. Furthermore, the calculations predict that substituting the Pro(110) residue with an Ala will change the conformation to a straight hydrophobic helix that would traverse the membrane. We have expressed the P110A mutant of caveolin-1, with a FLAG tag at the N terminus, in HEK 293 cells. We evaluate the topology of the proteins with confocal immunofluorescence microscopy in these cells. We find that FLAG tag at the N terminus of the wild type caveolin-1 is not reactive with antibodies unless the cell membrane is permeabilized with detergent. This indicates that in these cells, the hydrophobic segment of this protein is not transmembrane but takes up a bent conformation, making the protein monotopic. In contrast, the FLAG tag at the N terminus of the P110A mutant is equally exposed to antibodies, before and after membrane permeabilization. We also find that the P110A mutation causes a large reduction of endocytosis of caveolae, cellular lipid accumulation, and lipid droplet formulation. In addition, we find that this mutation markedly reduces the ability of caveolin-1 to form structures with the characteristic morphology of caveolae or to partition into the detergent-resistant membranes of these cells. Thus, the single Pro residue in the membrane-inserting segment of caveolin-1 plays an important role in both the membrane topology and localization of the protein as well as its functions.
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Affiliation(s)
- Satoko Aoki
- From the Department of Biochemistry and Biomedical Sciences, McMaster University Health Science Center, Hamilton, Ontario L8N 3Z5, Canada
| | - Annick Thomas
- Centre de Biophysique Moléculaire Numérique, ULg Gembloux Agro-BioTech, Passage des Déportés 2, 5030 Gembloux, Belgium
| | - Marc Decaffmeyer
- Centre de Biophysique Moléculaire Numérique, ULg Gembloux Agro-BioTech, Passage des Déportés 2, 5030 Gembloux, Belgium
| | - Robert Brasseur
- Centre de Biophysique Moléculaire Numérique, ULg Gembloux Agro-BioTech, Passage des Déportés 2, 5030 Gembloux, Belgium
| | - Richard M Epand
- From the Department of Biochemistry and Biomedical Sciences, McMaster University Health Science Center, Hamilton, Ontario L8N 3Z5, Canada.
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Meisslitzer-Ruppitsch C, Röhrl C, Neumüller J, Pavelka M, Ellinger A. Photooxidation technology for correlated light and electron microscopy. J Microsc 2009; 235:322-35. [PMID: 19754726 DOI: 10.1111/j.1365-2818.2009.03220.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The combination of the capabilities of light microscopical techniques with the power of resolution of electron microscopy along with technical advances has led to a gradual decline of the gap between classical light and electron microscopy. Among the correlative techniques using the synergistic opportunities, photooxidation methods have been established as valuable tools for visualizing cell structures at both light and electron microscopic level. Fluorescent dyes are used to oxidize the substrate diaminobenzidine, which in its oxidized state forms fine granular precipitates. Stained with osmium, the diaminobenzidine precipitates are well discernible in the electron microscope, thus labelling and defining the cellular structures, which at light microscopy level are recorded by fluorescent probes. The underlying photooxidation reaction is based on the excitation of free oxygen radicals that form upon illumination of fluorochromes; this is a central step in the procedure, which mainly influences the success of the method. This article summarizes basic steps of the technology and progresses, shows efforts and elaborated pathways, and focuses on methodical solutions as to the applicability of different fluorochromes, as well as conditions for fine structural localizations of the reaction products.
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Affiliation(s)
- C Meisslitzer-Ruppitsch
- Department of Cell Biology and Ultrastructure Research, Centre for Anatomy and Cell Biology, Medical University Vienna, Vienna, Austria
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Campeau PM, Rafei M, Boivin MN, Sun Y, Grabowski GA, Galipeau J. Characterization of Gaucher disease bone marrow mesenchymal stromal cells reveals an altered inflammatory secretome. Blood 2009; 114:3181-90. [PMID: 19587377 PMCID: PMC2925728 DOI: 10.1182/blood-2009-02-205708] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2009] [Accepted: 06/24/2009] [Indexed: 01/03/2023] Open
Abstract
Gaucher disease causes pathologic skeletal changes that are not fully explained. Considering the important role of mesenchymal stromal cells (MSCs) in bone structural development and maintenance, we analyzed the cellular biochemistry of MSCs from an adult patient with Gaucher disease type 1 (N370S/L444P mutations). Gaucher MSCs possessed a low glucocerebrosidase activity and consequently had a 3-fold increase in cellular glucosylceramide. Gaucher MSCs have a typical MSC marker phenotype, normal osteocytic and adipocytic differentiation, growth, exogenous lactosylceramide trafficking, cholesterol content, lysosomal morphology, and total lysosomal content, and a marked increase in COX-2, prostaglandin E2, interleukin-8, and CCL2 production compared with normal controls. Transcriptome analysis on normal MSCs treated with the glucocerebrosidase inhibitor conduritol B epoxide showed an up-regulation of an array of inflammatory mediators, including CCL2, and other differentially regulated pathways. These cells also showed a decrease in sphingosine-1-phosphate. In conclusion, Gaucher disease MSCs display an altered secretome that could contribute to skeletal disease and immune disease manifestations in a manner distinct and additive to Gaucher macrophages themselves.
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Affiliation(s)
- Philippe M Campeau
- Montreal Centre for Experimental Therapeutics in Cancer, Lady Davis Institute for Medical Research, Montreal, QC, Canada
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Abstract
Astrocytes release ATP and glutamate through vesicular exocytosis to mediate neuron-glial interactions. In contrast to exocytosis, the endocytic pathways in astroglial cells are poorly understood. Here, we identify a constitutive endocytic pathway in cultured astrocytes that is dependent on neither clathrin nor dynamin. This dynamin-independent endocytic pathway is regulated by Rab5, an early endosome protein. The endocytosed vesicles show fast transition from early endosomes to late endosomes and lysosomes within a few minutes. Interestingly, this clathrin- and dynamin-independent endocytosis in astrocytes is potently regulated by intracellular Ca(2+). ATP and glutamate greatly enhance the dynamin-independent endocytosis through elevating the intracellular Ca(2+). In addition, amyloid-beta peptide (A beta) also enhances the dynamin-independent endocytosis by inducing Ca(2+) transients in astrocytes. These results demonstrate a novel endocytic pathway in glial cells that is dynamin independent but tightly regulated by intracellular Ca(2+). The regulation by ATP, glutamate, and A beta suggests an important role of the dynamin-independent endocytosis in both physiological and pathological conditions.
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Parker S, Walker DS, Ly S, Baylis HA. Caveolin-2 is required for apical lipid trafficking and suppresses basolateral recycling defects in the intestine of Caenorhabditis elegans. Mol Biol Cell 2009; 20:1763-71. [PMID: 19158391 PMCID: PMC2655242 DOI: 10.1091/mbc.e08-08-0837] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 12/08/2008] [Accepted: 01/13/2009] [Indexed: 12/30/2022] Open
Abstract
Caveolins are plasma membrane-associated proteins that colocalize with, and stabilize caveolae. Their functions remain unclear although they are known to be involved in specific events in cell signaling and endocytosis. Caenorhabditis elegans encodes two caveolin genes, cav-1 and cav-2. We show that cav-2 is expressed in the intestine where it is localized to the apical membrane and in intracellular bodies. Using the styryl dye FM4-64 and BODIPY-labeled lactosylceramide, we show that the intestinal cells of cav-2 animals are defective in the apical uptake of lipid markers. These results suggest parallels with the function of caveolins in lipid homeostasis in mammals. We also show that CAV-2 depletion suppresses the abnormal accumulation of vacuoles that result from defective basolateral recycling in rme-1 and rab-10 mutants. Analysis of fluorescent markers of basolateral endocytosis and recycling suggest that endocytosis is normal in cav-2 mutants and thus, that the suppression of basolateral recycling defects in cav-2 mutants is due to changes in intracellular trafficking pathways. Finally, cav-2 mutants also have abnormal trafficking of yolk proteins. Taken together, these data indicate that caveolin-2 is an integral component of the trafficking network in the intestinal cells of C. elegans.
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Affiliation(s)
- Scott Parker
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, United Kingdom
| | - Denise S. Walker
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, United Kingdom
| | - Sung Ly
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, United Kingdom
| | - Howard A. Baylis
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, United Kingdom
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Marks DL, Bittman R, Pagano RE. Use of Bodipy-labeled sphingolipid and cholesterol analogs to examine membrane microdomains in cells. Histochem Cell Biol 2008; 130:819-32. [PMID: 18820942 PMCID: PMC3922293 DOI: 10.1007/s00418-008-0509-5] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2008] [Indexed: 01/28/2023]
Abstract
Much evidence has accumulated to show that cellular membranes such as the plasma membrane, contain multiple "microdomains" of differing lipid and protein composition and function. These domains are sometimes enriched in cholesterol and sphingolipids and are believed to be important structures for the regulation of many biological and pathological processes. This review focuses on the use of fluorescent (Bodipy) labeled analogs of sphingolipids and cholesterol to study such domains. We discuss the similarities between the behavior of Bodipy-cholesterol and natural cholesterol in artificial bilayers and in cultured cells, and the use of Bodipy-sphingolipid analogs to visualize membrane domains in living cells based on the concentration-dependent monomer-excimer fluorescence properties of the Bodipy-fluorophore. The use of Bodipy-D-erythro-lactosylceramide is highlighted for detection of domains on the plasma membrane and endosome membranes, and the importance of the sphingolipid stereochemistry in modulating domain formation is discussed. Finally, we suggest that Bodipy-sphingolipids may be useful in future studies to examine the relationship between membrane domains at the cell surface and domains enriched in other lipids and proteins on the inner leaflet of the plasma membrane.
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Affiliation(s)
- David L. Marks
- Thoracic Diseases Research Unit, Department of Medicine, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
| | - Robert Bittman
- Department of Chemistry and Biochemistry, Queens College, The City University of New York, Flushing, NY 11367, USA
| | - Richard E. Pagano
- Thoracic Diseases Research Unit, Department of Medicine, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Stabile 8, 200 First Street, SW, Rochester, MN 55905-0001, USA
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