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Björkqvist YJE, Nyholm TKM, Slotte JP, Ramstedt B. Domain formation and stability in complex lipid bilayers as reported by cholestatrienol. Biophys J 2005; 88:4054-63. [PMID: 15792981 PMCID: PMC1305636 DOI: 10.1529/biophysj.104.054718] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In this study, we used cholestatrienol (CTL) as a fluorescent reporter molecule to study sterol-rich L(o) domains in complex lipid bilayers. CTL is a fluorescent cholesterol analog that mimics the behavior of cholesterol well. The ability of 12SLPC to quench the fluorescence of cholestatrienol gives a measure of the amount of sterol included in L(o) domains in mixed lipid membranes. The stability of sterol-rich domains formed in complex lipid mixtures containing saturated sphingomyelins, phosphatidylcholines, or galactosylceramide as potential domain-forming lipids were studied. The amount of sterol associated with sterol-rich domains seemed to always increase with increasing temperature. The quenching efficiency was highly dependent on the domain-forming lipid present in complex lipid mixtures. Sphingomyelins formed stable sterol-enriched domains and were able to shield CTL from quenching better than the other lipids included in this study. The saturated phosphatidylcholines also formed sterol-rich domains, but the quenching efficiency in membranes with these was higher than with sphingomyelins and the domains melted at lower temperatures. PGalCer was not able to form sterol-enriched domains. However, we found that PGalCer stabilized sterol-rich domains formed in PSM-containing bilayers. Using a fluorescent ceramide analog, we also demonstrated that N-palmitoyl-ceramide displaced the sterol from sphingolipid-rich domains in mixed bilayer membranes.
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Térová B, Heczko R, Slotte JP. On the importance of the phosphocholine methyl groups for sphingomyelin/cholesterol interactions in membranes: a study with ceramide phosphoethanolamine. Biophys J 2005; 88:2661-9. [PMID: 15653729 PMCID: PMC1305362 DOI: 10.1529/biophysj.104.058149] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In this study, we have examined how the headgroup size and properties affect the membrane properties of sphingomyelin and interactions with cholesterol. We prepared N-palmitoyl ceramide phosphoethanolamine (PCPE) and compared its membrane behavior with D-erythro-N-palmitoyl-sphingomyelin (PSM), both in monolayers and bilayers. The pure PCPE monolayer did not show a phase transition at 22 degrees C (in contrast to PSM), but displayed a much higher inverse isothermal compressibility as compared to the PSM monolayer, indicating stronger intermolecular interactions between PCPEs than between PSMs. At 37 degrees C the PCPE monolayer was more expanded (than at 22 degrees C) and displayed a rather poorly defined phase transition. When cholesterol was comixed into the monolayer, a condensing effect of cholesterol on the lateral packing of the lipids in the monolayer could be observed. The phase transition from an ordered to a disordered state in bilayer membranes was determined by diphenylhexatriene steady-state anisotropy. Whereas the PSM bilayer became disordered at 41 degrees C, the PCPE bilayer main transition occurred around 64 degrees C. The diphenylhexatriene steady-state anisotropy values were similar in both PCPE and PSM bilayers before and after the phase transition, suggesting that the order in the hydrophobic core in both bilayer types was rather similar. The emission from Laurdan was blue shifted in PCPE bilayers in the gel phase when compared to the emission spectra from PSM bilayers, and the blue-shifted component in PCPE bilayers was retained also after the phase transition, suggesting that Laurdan molecules sensed a more hydrophobic environment at the PCPE interface compared to the PSM interface both below and above the bilayer melting temperature. Whereas PSM was able to form sterol-enriched domains in dominantly fluid bilayers (as determined from cholestatrienol dequenching experiments), PCPE failed to form such domains, suggesting that the size and/or properties of the headgroup was important for stabilizing sphingolipid/sterol interaction. In conclusion, our study has highlighted how the headgroup in sphingomyelin affect its membrane properties and interactions with cholesterol.
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Affiliation(s)
- Bohdana Térová
- Department of Biochemistry and Pharmacy, Abo Akademi University, Turku, Finland
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Abstract
Niemann-Pick type C, or NPC for short, is an early childhood disease exhibiting progressive neurological degeneration, associated with hepatosplenomegaly in some cases. The disease, at the cellular level, is a result of improper trafficking of lipids such as cholesterol and glycosphingolipids (GSLs) to lysosome-like storage organelles (LSOs), which become engorged with these lipids. It is believed that the initial defect in trafficking, whether of cholesterol or a GSL, results in an eventual traffic jam in these LSOs. This leads to the retention of not only other lipids, but also of transmembrane proteins that transiently associate with the late endosomes (LE) in normal cells, on their way to other cellular destinations such as the trans-Golgi network (TGN). In this review, we discuss the biophysical properties of lipids and cholesterol that might determine their intracellular itineraries, and how these itineraries are altered in NPC cells, which have defects in the proteins NPC1 or NPC2. We also discuss some potential therapeutic directions being suggested by recent research.
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Affiliation(s)
- Sushmita Mukherjee
- Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
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Polishchuk R, Di Pentima A, Lippincott-Schwartz J. Delivery of raft-associated, GPI-anchored proteins to the apical surface of polarized MDCK cells by a transcytotic pathway. Nat Cell Biol 2004; 6:297-307. [PMID: 15048124 DOI: 10.1038/ncb1109] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Accepted: 03/04/2004] [Indexed: 02/07/2023]
Abstract
Epithelial cell polarity depends on mechanisms for targeting proteins to different plasma membrane domains. Here, we dissect the pathway for apical delivery of several raft-associated, glycosyl phosphatidylinositol (GPI)-anchored proteins in polarized MDCK cells using live-cell imaging and selective inhibition of apical or basolateral exocytosis. Rather than trafficking directly from the trans-Golgi network (TGN) to the apical plasma membrane as previously thought, the GPI-anchored proteins followed an indirect, transcytotic route. They first exited the TGN in membrane-bound carriers that also contained basolateral cargo, although the two cargoes were laterally segregated. The carriers were then targeted to and fused with a zone of lateral plasma membrane adjacent to tight junctions that is known to contain the exocyst. Thereafter, the GPI-anchored proteins, but not basolateral cargo, were rapidly internalized, together with endocytic tracer, into clathrin-free transport intermediates that transcytosed to the apical plasma membrane. Thus, apical sorting of these GPI-anchored proteins occurs at the plasma membrane, rather than at the TGN.
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Affiliation(s)
- Roman Polishchuk
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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van der Wouden JM, Maier O, van IJzendoorn SCD, Hoekstra D. Membrane dynamics and the regulation of epithelial cell polarity. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 226:127-64. [PMID: 12921237 DOI: 10.1016/s0074-7696(03)01003-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Plasma membranes of epithelial cells consist of two domains, an apical and a basolateral domain, the surfaces of which differ in composition. The separation of these domains by a tight junction and the fact that specific transport pathways exist for intracellular communication between these domains and distinct intracellular compartments relevant to cell polarity development, have triggered extensive research on issues that focus on how the polarity is generated and maintained. Apart from proper assembly of tight junctions, their potential functioning as landmark for the transport machinery, cell-cell adhesion is obviously instrumental in barrier formation. In recent years, distinct endocytic compartments, defined as subapical compartment or common endosome, were shown to play a prominent role in regulating membrane trafficking to and from polarized membrane domains. Sorting devices remain to be determined but likely include distinct rab proteins, and evidence is accumulating to indicate that signaling events may direct intracellular membrane transport, intimately involved in the biogenesis and maintenance of polarized membrane domains and hence the development of cell polarity.
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Affiliation(s)
- Johanna M van der Wouden
- Department of Membrane Cell Biology, University of Groningen, Antonius Deusinglaan 1, 9713AV Groningen, The Netherlands
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Rappleye CA, Tagawa A, Le Bot N, Ahringer J, Aroian RV. Involvement of fatty acid pathways and cortical interaction of the pronuclear complex in Caenorhabditis elegans embryonic polarity. BMC DEVELOPMENTAL BIOLOGY 2003; 3:8. [PMID: 14527340 PMCID: PMC270048 DOI: 10.1186/1471-213x-3-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2003] [Accepted: 10/03/2003] [Indexed: 11/21/2022]
Abstract
Background Cell polarity is essential for many decisions made during development. While investigation of polarity-specific factors has yielded great insights into the polarization process, little is known on how these polarity-specific factors link to the basic cellular mechanisms that function in non-polarity aspects of the cell. To better understand the mechanisms that establish embryonic polarity, we investigated genes required for polarity in the one-cell C. elegans embryo that are also required for other non-polarity functions. This has led to the identification of the Pod-class of mutants that are characterized by osmosensitive embryos and defects in anterior-posterior polarity. Results Mutation in either of two loci of this class, emb-8 and pod-2, disrupts embryonic polarization and results in osmotically-sensitive embryos. Loss of emb-8, a previously uncharacterized polarity gene, causes mislocalization of PAR-3 and PAR-2 that molecularly mark the anterior and posterior cortices. emb-8 encodes NADPH-cytochrome P450 reductase, a protein supplying electrons to cytochrome P450-family enzymes, some of which catalyze fatty acid modifications. Cloning of the previously characterized polarity gene pod-2 reveals it encodes acetyl-CoA carboxylase, an enzyme that catalyzes the first step in de novo fatty acid synthesis. Depletion of fatty acid synthase, the next enzyme in the biosynthetic pathway, by RNA-interference (RNAi) also causes similar loss of one-cell polarity. Furthermore, pod-2 polarity defects can be rescued by addition of exogenous fatty acids. By following the behavior of the pronucleus in emb-8 and pod-2 mutant embryos, we demonstrate that loss of polarity correlates with impaired interaction between the pronucleus-centrosome complex and the posterior cortex. Conclusions The characterization of emb-8 and pod-2 mutant embryos suggests that the pronucleus-centrosome complex interaction with the cortex plays a direct role in establishing polarity and that fatty acid pathways are important for this polarizing event.
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Affiliation(s)
- Chad A Rappleye
- present address: Dept. Molecular Microbiology, Washington University, St. Louis, MO 63110, U.S.A
| | - Akiko Tagawa
- present address: Inst. Biochemistry, ETH Hönggerberg, CH-8093 Zürich, Switzerland
| | - Nathalie Le Bot
- Wellcome Trust/CR UK Institute, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Julie Ahringer
- Wellcome Trust/CR UK Institute, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Raffi V Aroian
- Section of Cell and Developmental Biology, Univ. of California, San Diego, La Jolla, CA 92093, U.S.A
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Wallrabe H, Elangovan M, Burchard A, Periasamy A, Barroso M. Confocal FRET microscopy to measure clustering of ligand-receptor complexes in endocytic membranes. Biophys J 2003; 85:559-71. [PMID: 12829510 PMCID: PMC1303111 DOI: 10.1016/s0006-3495(03)74500-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The dynamics of protein distribution in endocytic membranes are relevant for many cellular processes, such as protein sorting, organelle and membrane microdomain biogenesis, protein-protein interactions, receptor function, and signal transduction. We have developed an assay based on Fluorescence Resonance Energy Microscopy (FRET) and novel mathematical models to differentiate between clustered and random distributions of fluorophore-bound molecules on the basis of the dependence of FRET intensity on donor and acceptor concentrations. The models are tailored to extended clusters, which may be tightly packed, and account for geometric exclusion effects between membrane-bound proteins. Two main criteria are used to show that labeled polymeric IgA-ligand-receptor complexes are organized in clusters within apical endocytic membranes of polarized MDCK cells: 1), energy transfer efficiency (E%) levels are independent of acceptor levels; and 2), with increasing unquenched donor: acceptor ratio, E% decreases. A quantitative analysis of cluster density indicates that a donor-labeled ligand-receptor complex should have 2.5-3 labeled complexes in its immediate neighborhood and that clustering may occur at a limited number of discrete membrane locations and/or require a specific protein that can be saturated. Here, we present a new sensitive FRET-based method to quantify the co-localization and distribution of ligand-receptor complexes in apical endocytic membranes of polarized cells.
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Affiliation(s)
- Horst Wallrabe
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904, USA
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Hansen GH, Pedersen J, Niels-Christiansen LL, Immerdal L, Danielsen EM. Deep-apical tubules: dynamic lipid-raft microdomains in the brush-border region of enterocytes. Biochem J 2003; 373:125-32. [PMID: 12689332 PMCID: PMC1223483 DOI: 10.1042/bj20030235] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2003] [Revised: 04/02/2003] [Accepted: 04/10/2003] [Indexed: 11/17/2022]
Abstract
The brush border of small intestinal enterocytes is highly enriched in cholesterol- and glycosphingolipid-containing membrane microdomains, commonly termed as lipid 'rafts'. Functionally, transcytosis of IgA and exocytosis of newly made brush-border proteins in enterocytes occur through apical lipid raft-containing compartments, but little is otherwise known about these raft microdomains. We therefore studied in closer detail apical lipid-raft compartments in enterocytes by immunogold electron microscopy and biochemical analyses. Novel membrane structures, deep-apical tubules, were visualized by the non-permeable surface marker Ruthenium Red in the brush-border region of the cells. The surface-connected tubules were labelled by antibodies to caveolin-1 and the glycolipid asialo G(M1), and they were sensitive to cholesterol depletion by methyl-beta-cyclodextrin, indicating the presence of raft microdomains. Deep-apical tubules were positioned close to the actin rootlets of adjacent microvilli in the terminal web region, which had a diameter of 50-100 nm, and penetrated up to 1 microm into the cytoplasm. Markers for transcytosis, IgA and the polymeric immunoglobulin receptor, as well as the resident brush-border enzyme aminopeptidase N, were present in these deep-apical tubules. We propose that deep-apical tubules are a specialized lipid-raft microdomain in the brush-border region functioning as a hub in membrane trafficking at the brush border. In addition, the sensitivity to cholesterol depletion suggests that deep-apical tubules function as a cell-surface membrane reservoir for cholesterol and for rapid adaptive changes in the size of microvilli at the brush border.
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Affiliation(s)
- Gert H Hansen
- Department of Medical Biochemistry and Genetics, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
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Hoekstra D, Maier O, van der Wouden JM, Slimane TA, van IJzendoorn SCD. Membrane dynamics and cell polarity: the role of sphingolipids. J Lipid Res 2003; 44:869-77. [PMID: 12639977 DOI: 10.1194/jlr.r300003-jlr200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In recent years, glycosphingolipids (GSLs) have attracted widespread attention due to the appreciation that this class of lipids has a major impact on biological life. Inhibition of the synthesis of glucosylceramide, which serves as a precursor for the generation of complex glycosphinglipids, is embryonic lethal. GSLs play a major role in growth and development. Metabolites of sphingolipids, such as ceramide, sphinganine, and sphingosine, may function as second messengers or regulators of signal transduction that affect events ranging from apoptosis to the (co)regulation of the cell cycle. In addition, GSLs can provide a molecular platform for clustering of signal transducers. The ability of sphingolipids, with or without cholesterol, to form microdomains or rafts is critical in sorting and membrane transport that underlies the biogenesis of polarized membrane domains. Here, a brief summary is presented of some recent developments in this field, with a particular emphasis on raft assembly and membrane transport in the establishment of membrane polarity.
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Affiliation(s)
- Dick Hoekstra
- University of Groningen, Department of Membrane Cell Biology, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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Slimane TA, Trugnan G, Van IJzendoorn SCD, Hoekstra D. Raft-mediated trafficking of apical resident proteins occurs in both direct and transcytotic pathways in polarized hepatic cells: role of distinct lipid microdomains. Mol Biol Cell 2003; 14:611-24. [PMID: 12589058 PMCID: PMC149996 DOI: 10.1091/mbc.e02-08-0528] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2002] [Revised: 10/04/2002] [Accepted: 10/25/2002] [Indexed: 11/11/2022] Open
Abstract
In polarized hepatic cells, pathways and molecular principles mediating the flow of resident apical bile canalicular proteins have not yet been resolved. Herein, we have investigated apical trafficking of a glycosylphosphatidylinositol-linked and two single transmembrane domain proteins on the one hand, and two polytopic proteins on the other in polarized HepG2 cells. We demonstrate that the former arrive at the bile canalicular membrane via the indirect transcytotic pathway, whereas the polytopic proteins reach the apical membrane directly, after Golgi exit. Most importantly, cholesterol-based lipid microdomains ("rafts") are operating in either pathway, and protein sorting into such domains occurs in the biosynthetic pathway, largely in the Golgi. Interestingly, rafts involved in the direct pathway are Lubrol WX insoluble but Triton X-100 soluble, whereas rafts in the indirect pathway are both Lubrol WX and Triton X-100 insoluble. Moreover, whereas cholesterol depletion alters raft-detergent insolubility in the indirect pathway without affecting apical sorting, protein missorting occurs in the direct pathway without affecting raft insolubility. The data implicate cholesterol as a traffic direction-determining parameter in the direct apical pathway. Furthermore, raft-cargo likely distinguishing single vs. multispanning membrane anchors, rather than rafts per se (co)determine the sorting pathway.
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Affiliation(s)
- Tounsia Aït Slimane
- Department of Membrane Cell Biology, University of Groningen, The Netherlands
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van Ijzendoorn SCD, Mostov KE, Hoekstra D. Role of Rab Proteins in Epithelial Membrane Traffic. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 232:59-88. [PMID: 14711116 DOI: 10.1016/s0074-7696(03)32002-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Small GTPase rab proteins play an important role in various aspects of membrane traffic, including cargo selection, vesicle budding, vesicle motility, tethering, docking, and fusion. Recent data suggest also that rabs, and their divalent effector proteins, organize organelle subdomains and as such may define functional organelle identity. Most rabs are ubiquitously expressed. However, some rabs are preferentially expressed in epithelial cells where they appear intimately associated with the epithelial-specific transcytotic pathway and/or tight junctions. This review discusses the role of rabs in epithelial membrane transport.
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Affiliation(s)
- Sven C D van Ijzendoorn
- Department of Membrane Cell Biology, University of Groningen, Groningen 9713AV, The Netherlands
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van der Wouden JM, van IJzendoorn SC, Hoekstra D. Oncostatin M regulates membrane traffic and stimulates bile canalicular membrane biogenesis in HepG2 cells. EMBO J 2002; 21:6409-18. [PMID: 12456648 PMCID: PMC136933 DOI: 10.1093/emboj/cdf629] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Hepatocytes are the major epithelial cells of the liver and they display membrane polarity: the sinusoidal membrane representing the basolateral surface, while the bile canalicular membrane is typical of the apical membrane. In polarized HepG2 cells an endosomal organelle, SAC, fulfills a prominent role in the biogenesis of the canalicular membrane, reflected by its ability to sort and redistribute apical and basolateral sphingolipids. Here we show that SAC appears to be a crucial target for a cytokine-induced signal transduction pathway, which stimulates membrane transport exiting from this compartment promoting apical membrane biogenesis. Thus, oncostatin M, an IL-6-type cytokine, stimulates membrane polarity development in HepG2 cells via the gp130 receptor unit, which activates a protein kinase A-dependent and sphingomyelin-marked membrane transport pathway from SAC to the apical membrane. To exert its signal transducing function, gp130 is recruited into detergent-resistant membrane microdomains at the basolateral membrane. These data provide a clue for a molecular mechanism that couples the biogenesis of an apical plasma membrane domain to the regulation of intracellular transport in response to an extracellular, basolaterally localized stimulus.
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Affiliation(s)
| | | | - Dick Hoekstra
- Department of Membrane Cell Biology, University of Groningen, Antonius Deusinglaan 1, 9713AV Groningen, The Netherlands
Corresponding author e-mail:
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Safieddine S, Ly CD, Wang YX, Wang CY, Kachar B, Petralia RS, Wenthold RJ. Ocsyn, a novel syntaxin-interacting protein enriched in the subapical region of inner hair cells. Mol Cell Neurosci 2002; 20:343-53. [PMID: 12093165 DOI: 10.1006/mcne.2002.1120] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sensory (hair) cells of the inner ear contain two specialized areas of membrane delivery. The first, located at the cell base, is the afferent synapse where rapid delivery of synaptic vesicles is required to convey information about auditory signals with exceedingly high temporal precision. The second area is at the apex. To accommodate the continuous movement of stereocilia and facilitate their repair, recycling of membrane components is required. Intense vesicular traffic is restricted to a narrow band of cytoplasm around the cuticular plate, which anchors stereocilia. Our previous analyses showed that SNARE proteins (syntaxin 1A/SNAP25/VAMP1) are concentrated at both poles of hair cells, consistent with their involvement in membrane delivery at both locations. To investigate further the molecules involved in membrane delivery at these two sites, we constructed a two-hybrid library of the organ of Corti and probed it with syntaxin 1A. Here we report the cloning of a novel syntaxin-binding protein that is concentrated in a previously uncharacterized organelle at the apex of inner hair cells.
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Affiliation(s)
- S Safieddine
- Laboratory of Neurochemistry, National Institute on Deafness and Other Communication Disorders, Bethesda, Maryland 20892, USA
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Herreros J, Schiavo G. Lipid microdomains are involved in neurospecific binding and internalisation of clostridial neurotoxins. Int J Med Microbiol 2002; 291:447-53. [PMID: 11890543 DOI: 10.1078/1438-4221-00152] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The neuroparalytic syndromes of tetanus and botulism are caused by tetanus and botulinum neurotoxins, which are produced by bacteria of the genus Clostridia. These neurotoxins are structurally organised in three-domains endowed with different functions: specific interaction with the neuronal surface, membrane translocation and specific cleavage of three key components of the neurotransmitter release apparatus. Despite an identical intracellular activity, tetanus and botulinum neurotoxins are characterised by a differential intraneuronal trafficking, which is likely to be responsible for the different symptoms observed in clinical tetanus and botulism. This review aims to highlight recent discoveries on the recruitment of clostridial neurotoxins (CNTs) to the surface of neurons and neuronally-differentiated cell lines and to discuss their relevance for the internalisation and sorting of these neurotoxins.
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Affiliation(s)
- Judit Herreros
- Molecular Neuropathobiology Laboratory, Imperial Cancer Research Fund, London, United Kingdom.
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