51
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Weber DK, Yao S, Rojko N, Anderluh G, Lybrand TP, Downton MT, Wagner J, Separovic F. Characterization of the Lipid-Binding Site of Equinatoxin II by NMR and Molecular Dynamics Simulation. Biophys J 2016; 108:1987-96. [PMID: 25902438 DOI: 10.1016/j.bpj.2015.03.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/09/2015] [Accepted: 03/12/2015] [Indexed: 12/26/2022] Open
Abstract
Equinatoxin II (EqtII) is a soluble, 20 kDa pore-forming protein toxin isolated from the sea anemone Actinia equina. Although pore formation has long been known to occur in distinct stages, including monomeric attachment to phospholipid membranes followed by detachment of the N-terminal helical domain and oligomerization into the final pore assembly, atomistic-level detail of the protein-lipid interactions underlying these events remains elusive. Using high-resolution solution state NMR of uniformly-(15)N-labeled EqtII at the critical micelle concentration of dodecylphosphocholine, we have mapped the lipid-binding site through chemical shift perturbations. Subsequent docking of an EqtII monomer onto a dodecylphosphocholine micelle, followed by 400 ns of all-atom molecular dynamics simulation, saw several high-occupancy lipid-binding pockets stabilized by cation-π, hydrogen bonding, and hydrophobic interactions; and stabilization of the loop housing the conserved arginine-glycine-aspartate motif. Additional simulation of EqtII with an N-acetyl sphingomyelin micelle, for which high-resolution NMR data cannot be obtained due to aggregate formation, revealed that sphingomyelin specificity might occur via hydrogen bonding to the 3-OH and 2-NH groups unique to the ceramide backbone by side chains of D109 and Y113; and main chains of P81 and W112. Furthermore, a binding pocket formed by K30, K77, and P81, proximate to the hinge region of the N-terminal helix, was identified and may be implicated in triggering pore formation.
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Affiliation(s)
- Daniel K Weber
- School of Chemistry, University of Melbourne, Victoria, Australia; Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Shenggen Yao
- Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Nejc Rojko
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Terry P Lybrand
- Center for Structural Biology, Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - Matthew T Downton
- IBM Research Collaboratory for Life Sciences, Victorian Life Sciences Computation Initiative, University of Melbourne, Victoria, Australia
| | - John Wagner
- IBM Research Collaboratory for Life Sciences, Victorian Life Sciences Computation Initiative, University of Melbourne, Victoria, Australia
| | - Frances Separovic
- School of Chemistry, University of Melbourne, Victoria, Australia; Bio21 Institute, University of Melbourne, Victoria, Australia.
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52
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Roderer D, Benke S, Schuler B, Glockshuber R. Soluble Oligomers of the Pore-forming Toxin Cytolysin A from Escherichia coli Are Off-pathway Products of Pore Assembly. J Biol Chem 2016; 291:5652-5663. [PMID: 26757820 DOI: 10.1074/jbc.m115.700757] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Indexed: 11/06/2022] Open
Abstract
The α-pore-forming toxin Cytolysin A (ClyA) is responsible for the hemolytic activity of various Escherichia coli and Salmonella enterica strains. Soluble ClyA monomers spontaneously assemble into annular dodecameric pore complexes upon contact with membranes or detergent. At ClyA monomer concentrations above ∼100 nm, the rate-limiting step in detergent- or membrane- induced pore assembly is the unimolecular reaction from the monomer to the assembly-competent protomer, which then oligomerizes rapidly to active pore complexes. In the absence of detergent, ClyA slowly forms soluble oligomers. Here we show that soluble ClyA oligomers cannot form dodecameric pore complexes after the addition of detergent and are hemolytically inactive. In addition, we demonstrate that the natural cysteine pair Cys-87/Cys-285 of ClyA forms a disulfide bond under oxidizing conditions and that both the oxidized and reduced ClyA monomers assemble to active pores via the same pathway in the presence of detergent, in which an unstructured, monomeric intermediate is transiently populated. The results show that the oxidized ClyA monomer assembles to pore complexes about one order of magnitude faster than the reduced monomer because the unstructured intermediate of oxidized ClyA is less stable and dissolves more rapidly than the reduced intermediate. Moreover, we show that oxidized ClyA forms soluble, inactive oligomers in the absence of detergent much faster than the reduced monomer, providing an explanation for several contradictory reports in which oxidized ClyA had been described as inactive.
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Affiliation(s)
- Daniel Roderer
- From the Institute of Molecular Biology and Biophysics ETH Zurich, Otto-Stern-Weg 5, CH-8093 Zurich, Switzerland and.
| | - Stephan Benke
- the Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Benjamin Schuler
- the Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Rudi Glockshuber
- From the Institute of Molecular Biology and Biophysics ETH Zurich, Otto-Stern-Weg 5, CH-8093 Zurich, Switzerland and
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53
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Abstract
Pore forming toxins (PFTs) evolved to permeate the plasma membrane of target cells. This is achieved in a multistep mechanism that usually involves binding of soluble protein monomer to the lipid membrane, oligomerization at the plane of the membrane, and insertion of part of the polypeptide chain across the lipid membrane to form a conductive channel. Introduced pores allow uncontrolled transport of solutes across the membrane, inflicting damage to the target cell. PFTs are usually studied from the perspective of structure-function relationships, often neglecting the important role of the bulk membrane properties on the PFT mechanism of action. In this Account, we discuss how membrane lateral heterogeneity, thickness, and fluidity influence the pore forming process of PFTs. In general, lipid molecules are more accessible for binding in fluid membranes due to steric reasons. When PFT specifically binds ordered domains, it usually recognizes a specific lipid distribution pattern, like sphingomyelin (SM) clusters or SM/cholesterol complexes, and not individual lipid species. Lipid domains were also suggested to act as an additional concentration platform facilitating PFT oligomerization, but this is yet to be shown. The last stage in PFT action is the insertion of the transmembrane segment across the membranes to build the transmembrane pore walls. Conformational changes are a spontaneous process, and sufficient free energy has to be available for efficient membrane penetration. Therefore, fluid bilayers are permeabilized more readily in comparison to highly ordered and thicker liquid ordered lipid phase (Lo). Energetically more costly insertion into the Lo phase can be driven by the hydrophobic mismatch between the thinner liquid disordered phase (Ld) and large protein complexes, which are unable to tilt like single transmembrane segments. In the case of proteolipid pores, membrane properties can directly modulate pore size, stability, and even selectivity. Finally, events associated with pore formation can modulate properties of the lipid membrane and affect its organization. Model membranes do not necessarily reproduce the physicochemical properties of the native cellular membrane, and caution is needed when transferring results from model to native lipid membranes. In this context, the utilization of novel approaches that enable studying PFTs on living cells at a single molecule level should reveal complex protein-lipid membrane interactions in greater detail.
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Affiliation(s)
- Nejc Rojko
- Laboratory
for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Gregor Anderluh
- Laboratory
for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- Department
of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva
101, 1000 Ljubljana, Slovenia
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54
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Peraro MD, van der Goot FG. Pore-forming toxins: ancient, but never really out of fashion. Nat Rev Microbiol 2015; 14:77-92. [DOI: 10.1038/nrmicro.2015.3] [Citation(s) in RCA: 476] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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55
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Mulvihill E, van Pee K, Mari SA, Müller DJ, Yildiz Ö. Directly Observing the Lipid-Dependent Self-Assembly and Pore-Forming Mechanism of the Cytolytic Toxin Listeriolysin O. NANO LETTERS 2015; 15:6965-6973. [PMID: 26302195 DOI: 10.1021/acs.nanolett.5b02963] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Listeriolysin O (LLO) is the major virulence factor of Listeria monocytogenes and a member of the cholesterol-dependent cytolysin (CDC) family. Gram-positive pathogenic bacteria produce water-soluble CDC monomers that bind cholesterol-dependent to the lipid membrane of the attacked cell or of the phagosome, oligomerize into prepores, and insert into the membrane to form transmembrane pores. However, the mechanisms guiding LLO toward pore formation are poorly understood. Using electron microscopy and time-lapse atomic force microscopy, we show that wild-type LLO binds to membranes, depending on the presence of cholesterol and other lipids. LLO oligomerizes into arc- or slit-shaped assemblies, which merge into complete rings. All three oligomeric assemblies can form transmembrane pores, and their efficiency to form pores depends on the cholesterol and the phospholipid composition of the membrane. Furthermore, the dynamic fusion of arcs, slits, and rings into larger rings and their formation of transmembrane pores does not involve a height difference between prepore and pore. Our results reveal new insights into the pore-forming mechanism and introduce a dynamic model of pore formation by LLO and other CDC pore-forming toxins.
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Affiliation(s)
- Estefania Mulvihill
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich , Mattenstrasse 26, 4058 Basel, Switzerland
| | - Katharina van Pee
- Department of Structural Biology, Max-Planck-Institute of Biophysics , Max von Laue Str. 3, 60438 Frankfurt am Main, Germany
| | - Stefania A Mari
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich , Mattenstrasse 26, 4058 Basel, Switzerland
| | - Daniel J Müller
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich , Mattenstrasse 26, 4058 Basel, Switzerland
| | - Özkan Yildiz
- Department of Structural Biology, Max-Planck-Institute of Biophysics , Max von Laue Str. 3, 60438 Frankfurt am Main, Germany
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Cosentino K, Ros U, García-Sáez AJ. Assembling the puzzle: Oligomerization of α-pore forming proteins in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:457-466. [PMID: 26375417 DOI: 10.1016/j.bbamem.2015.09.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/26/2015] [Accepted: 09/09/2015] [Indexed: 12/21/2022]
Abstract
Pore forming proteins (PFPs) share the ability of creating pores that allow the passage of ions, proteins or other constituents through a wide variety of target membranes, ranging from bacteria to humans. They often cause cell death, as pore formation disrupts the membrane permeability barrier required for maintaining cell homeostasis. The organization into supramolecular complexes or oligomers that pierce the membrane is a common feature of PFPs. However, the molecular pathway of self-assembly and pore opening remains unclear. Here, we review the most recent discoveries in the mechanism of membrane oligomerization and pore formation of a subset of PFPs, the α-PFPs, whose pore-forming domains are formed by helical segments. Only now we are starting to grasp the molecular details of their function, mainly thanks to the introduction of single molecule microscopy and nanoscopy techniques. This article is part of a Special Issue entitled: Pore-forming toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Katia Cosentino
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Uris Ros
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany.,Center for Protein Studies, Havana University, Havana, Cuba
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.,Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
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57
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Rojko N, Dalla Serra M, Maček P, Anderluh G. Pore formation by actinoporins, cytolysins from sea anemones. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:446-56. [PMID: 26351738 DOI: 10.1016/j.bbamem.2015.09.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 11/30/2022]
Abstract
Actinoporins (APs) from sea anemones are ~20 kDa pore forming toxins with a β-sandwich structure flanked by two α-helices. The molecular mechanism of APs pore formation is composed of several well-defined steps. APs bind to membrane by interfacial binding site composed of several aromatic amino acid residues that allow binding to phosphatidylcholine and specific recognition of sphingomyelin. Subsequently, the N-terminal α-helix from the β-sandwich has to be inserted into the lipid/water interphase in order to form a functional pore. Functional studies and single molecule imaging revealed that only several monomers, 3-4, oligomerise to form a functional pore. In this model the α-helices and surrounding lipid molecules build toroidal pore. In agreement, AP pores are transient and electrically heterogeneous. On the contrary, crystallized oligomers of actinoporin fragaceatoxin C were found to be composed of eight monomers with no lipids present between the adjacent α-helices. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Maur Dalla Serra and Franco Gambale.
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Affiliation(s)
- Nejc Rojko
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Mauro Dalla Serra
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche & Fondazione Bruno Kessler, via alla Cascata 56/C, 38123 Trento, Italy
| | - Peter Maček
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
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58
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Valle A, Alvarado-Mesén J, Lanio M, Álvarez C, Barbosa J, Pazos I. The multigene families of actinoporins (part I): Isoforms and genetic structure. Toxicon 2015; 103:176-87. [DOI: 10.1016/j.toxicon.2015.06.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 05/31/2015] [Accepted: 06/23/2015] [Indexed: 11/24/2022]
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59
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Ros U, Rodríguez-Vera W, Pedrera L, Valiente PA, Cabezas S, Lanio ME, García-Sáez AJ, Alvarez C. Differences in activity of actinoporins are related with the hydrophobicity of their N-terminus. Biochimie 2015; 116:70-8. [DOI: 10.1016/j.biochi.2015.06.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 06/25/2015] [Indexed: 10/23/2022]
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60
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Cajnko MM, Marušić M, Kisovec M, Rojko N, Benčina M, Caserman S, Anderluh G. Listeriolysin O Affects the Permeability of Caco-2 Monolayer in a Pore-Dependent and Ca2+-Independent Manner. PLoS One 2015; 10:e0130471. [PMID: 26087154 PMCID: PMC4472510 DOI: 10.1371/journal.pone.0130471] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 05/20/2015] [Indexed: 12/20/2022] Open
Abstract
Listeria monocytogenes is a food and soil-borne pathogen that secretes a pore-forming toxin listeriolysin O (LLO) as its major virulence factor. We tested the effects of LLO on an intestinal epithelial cell line Caco-2 and compared them to an unrelated pore-forming toxin equinatoxin II (EqtII). Results showed that apical application of both toxins causes a significant drop in transepithelial electrical resistance (TEER), with higher LLO concentrations or prolonged exposure time needed to achieve the same magnitude of response than with EqtII. The drop in TEER was due to pore formation and coincided with rearrangement of claudin-1 within tight junctions and associated actin cytoskeleton; however, no significant increase in permeability to fluorescein or 3 kDa FITC-dextran was observed. Influx of calcium after pore formation affected the magnitude of the drop in TEER. Both toxins exhibit similar effects on epithelium morphology and physiology. Importantly, LLO action upon the membrane is much slower and results in compromised epithelium on a longer time scale at lower concentrations than EqtII. This could favor listerial invasion in hosts resistant to E-cadherin related infection.
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Affiliation(s)
- Miša Mojca Cajnko
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Maja Marušić
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Matic Kisovec
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Nejc Rojko
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Mojca Benčina
- Laboratory for Biotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Simon Caserman
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
- * E-mail:
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61
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The effect of cholesterol on the long-range network of interactions established among sea anemone Sticholysin II residues at the water-membrane interface. Mar Drugs 2015; 13:1647-65. [PMID: 25815890 PMCID: PMC4413179 DOI: 10.3390/md13041647] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/03/2015] [Accepted: 03/16/2015] [Indexed: 12/21/2022] Open
Abstract
Actinoporins are α-pore forming proteins with therapeutic potential, produced by sea anemones. Sticholysin II (StnII) from Stichodactyla helianthus is one of its most extensively characterized members. These proteins remain stably folded in water, but upon interaction with lipid bilayers, they oligomerize to form a pore. This event is triggered by the presence of sphingomyelin (SM), but cholesterol (Chol) facilitates pore formation. Membrane attachment and pore formation require changes involving long-distance rearrangements of residues located at the protein-membrane interface. The influence of Chol on membrane recognition, oligomerization, and/or pore formation is now studied using StnII variants, which are characterized in terms of their ability to interact with model membranes in the presence or absence of Chol. The results obtained frame Chol not only as an important partner for SM for functional membrane recognition but also as a molecule which significantly reduces the structural requirements for the mentioned conformational rearrangements to occur. However, given that the DOPC:SM:Chol vesicles employed display phase coexistence and have domain boundaries, the observed effects could be also due to the presence of these different phases on the membrane. In addition, it is also shown that the Arg51 guanidinium group is strictly required for membrane recognition, independently of the presence of Chol.
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62
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Morante K, Caaveiro JMM, Tanaka K, González-Mañas JM, Tsumoto K. A pore-forming toxin requires a specific residue for its activity in membranes with particular physicochemical properties. J Biol Chem 2015; 290:10850-61. [PMID: 25759390 DOI: 10.1074/jbc.m114.615211] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Indexed: 12/29/2022] Open
Abstract
The physicochemical landscape of the bilayer modulates membrane protein function. Actinoporins are a family of potent hemolytic proteins from sea anemones acting at the membrane level. This family of cytolysins preferentially binds to target membranes containing sphingomyelin, where they form lytic pores giving rise to cell death. Although the cytolytic activity of the actinoporin fragaceatoxin C (FraC) is sensitive to vesicles made of various lipid compositions, it is far from clear how this toxin adjusts its mechanism of action to a broad range of physiochemical landscapes. Herein, we show that the conserved residue Phe-16 of FraC is critical for pore formation in cholesterol-rich membranes such as those of red blood cells. The interaction of a panel of muteins of Phe-16 with model membranes composed of raft-like lipid domains is inactivated in cholesterol-rich membranes but not in cholesterol-depleted membranes. These results indicate that actinoporins recognize different membrane environments, resulting in a wider repertoire of susceptible target membranes (and preys) for sea anemones. In addition, this study has unveiled promising candidates for the development of protein-based biosensors highly sensitive to the concentration of cholesterol within the membrane.
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Affiliation(s)
- Koldo Morante
- From the Department of Bioengineering, Graduate School of Engineering and the Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain, and
| | - Jose M M Caaveiro
- From the Department of Bioengineering, Graduate School of Engineering and
| | - Koji Tanaka
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Juan Manuel González-Mañas
- the Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain, and
| | - Kouhei Tsumoto
- From the Department of Bioengineering, Graduate School of Engineering and Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan, the Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, Minato-ku, 108-8639 Tokyo, Japan
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63
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Benke S, Roderer D, Wunderlich B, Nettels D, Glockshuber R, Schuler B. The assembly dynamics of the cytolytic pore toxin ClyA. Nat Commun 2015; 6:6198. [PMID: 25652783 PMCID: PMC4347018 DOI: 10.1038/ncomms7198] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 01/05/2015] [Indexed: 12/15/2022] Open
Abstract
Pore-forming toxins are protein assemblies used by many organisms to disrupt the membranes of target cells. They are expressed as soluble monomers that assemble spontaneously into multimeric pores. However, owing to their complexity, the assembly processes have not been resolved in detail for any pore-forming toxin. To determine the assembly mechanism for the ring-shaped, homododecameric pore of the bacterial cytolytic toxin ClyA, we collected a diverse set of kinetic data using single-molecule spectroscopy and complementary techniques on timescales from milliseconds to hours, and from picomolar to micromolar ClyA concentrations. The entire range of experimental results can be explained quantitatively by a surprisingly simple mechanism. First, addition of the detergent n-dodecyl-β-D-maltopyranoside to the soluble monomers triggers the formation of assembly-competent toxin subunits, accompanied by the transient formation of a molten-globule-like intermediate. Then, all sterically compatible oligomers contribute to assembly, which greatly enhances the efficiency of pore formation compared with simple monomer addition.
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Affiliation(s)
- Stephan Benke
- University of Zurich, Department of Biochemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Daniel Roderer
- ETH Zurich, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
| | - Bengt Wunderlich
- University of Zurich, Department of Biochemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Daniel Nettels
- University of Zurich, Department of Biochemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Rudi Glockshuber
- ETH Zurich, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
| | - Benjamin Schuler
- University of Zurich, Department of Biochemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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64
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Subburaj Y, Ros U, Hermann E, Tong R, García-Sáez AJ. Toxicity of an α-pore-forming toxin depends on the assembly mechanism on the target membrane as revealed by single molecule imaging. J Biol Chem 2014; 290:4856-4865. [PMID: 25525270 DOI: 10.1074/jbc.m114.600676] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
α-Pore-forming toxins (α-PFTs) are ubiquitous defense tools that kill cells by opening pores in the target cell membrane. Despite their relevance in host/pathogen interactions, very little is known about the pore stoichiometry and assembly pathway leading to membrane permeabilization. Equinatoxin II (EqtII) is a model α-PFT from sea anemone that oligomerizes and forms pores in sphingomyelin-containing membranes. Here, we determined the spatiotemporal organization of EqtII in living cells by single molecule imaging. Surprisingly, we found that on the cell surface EqtII did not organize into a unique oligomeric form. Instead, it existed as a mixture of oligomeric species mostly including monomers, dimers, tetramers, and hexamers. Mathematical modeling based on our data supported a new model in which toxin clustering happened in seconds and proceeded via condensation of EqtII dimer units formed upon monomer association. Furthermore, altering the pathway of EqtII assembly strongly affected its toxic activity, which highlights the relevance of the assembly mechanism on toxicity.
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Affiliation(s)
- Yamunadevi Subburaj
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany; German Cancer Research Center, Bioquant, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Uris Ros
- Center for Protein Studies, Faculty of Biology, Calle 25 #455, Plaza de la Revolución, La Habana, Cuba
| | - Eduard Hermann
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany; German Cancer Research Center, Bioquant, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany,; Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
| | - Rudi Tong
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Ana J García-Sáez
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany; German Cancer Research Center, Bioquant, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany,; Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
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65
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Kelker MS, Berry C, Evans SL, Pai R, McCaskill DG, Wang NX, Russell JC, Baker MD, Yang C, Pflugrath JW, Wade M, Wess TJ, Narva KE. Structural and biophysical characterization of Bacillus thuringiensis insecticidal proteins Cry34Ab1 and Cry35Ab1. PLoS One 2014; 9:e112555. [PMID: 25390338 PMCID: PMC4229197 DOI: 10.1371/journal.pone.0112555] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 10/07/2014] [Indexed: 11/18/2022] Open
Abstract
Bacillus thuringiensis strains are well known for the production of insecticidal proteins upon sporulation and these proteins are deposited in parasporal crystalline inclusions. The majority of these insect-specific toxins exhibit three domains in the mature toxin sequence. However, other Cry toxins are structurally and evolutionarily unrelated to this three-domain family and little is known of their three dimensional structures, limiting our understanding of their mechanisms of action and our ability to engineer the proteins to enhance their function. Among the non-three domain Cry toxins, the Cry34Ab1 and Cry35Ab1 proteins from B. thuringiensis strain PS149B1 are required to act together to produce toxicity to the western corn rootworm (WCR) Diabrotica virgifera virgifera Le Conte via a pore forming mechanism of action. Cry34Ab1 is a protein of ∼14 kDa with features of the aegerolysin family (Pfam06355) of proteins that have known membrane disrupting activity, while Cry35Ab1 is a ∼44 kDa member of the toxin_10 family (Pfam05431) that includes other insecticidal proteins such as the binary toxin BinA/BinB. The Cry34Ab1/Cry35Ab1 proteins represent an important seed trait technology having been developed as insect resistance traits in commercialized corn hybrids for control of WCR. The structures of Cry34Ab1 and Cry35Ab1 have been elucidated to 2.15 Å and 1.80 Å resolution, respectively. The solution structures of the toxins were further studied by small angle X-ray scattering and native electrospray ion mobility mass spectrometry. We present here the first published structure from the aegerolysin protein domain family and the structural comparisons of Cry34Ab1 and Cry35Ab1 with other pore forming toxins.
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Affiliation(s)
- Matthew S. Kelker
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Colin Berry
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Steven L. Evans
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Reetal Pai
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | | | - Nick X. Wang
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Joshua C. Russell
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
| | - Matthew D. Baker
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Cheng Yang
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - J. W. Pflugrath
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - Matthew Wade
- School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Tim J. Wess
- School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Kenneth E. Narva
- Dow AgroSciences, LLC, Indianapolis, Indiana, United States of America
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Antonini V, Pérez-Barzaga V, Bampi S, Pentón D, Martínez D, Serra MD, Tejuca M. Functional characterization of sticholysin I and W111C mutant reveals the sequence of the actinoporin's pore assembly. PLoS One 2014; 9:e110824. [PMID: 25350457 PMCID: PMC4211696 DOI: 10.1371/journal.pone.0110824] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/19/2014] [Indexed: 12/20/2022] Open
Abstract
The use of pore-forming toxins in the construction of immunotoxins against tumour cells is an alternative for cancer therapy. In this protein family one of the most potent toxins are the actinoporins, cytolysins from sea anemones. We work on the construction of tumour proteinase-activated immunotoxins using sticholysin I (StI), an actinoporin isolated from the sea anemone Stichodactyla helianthus. To accomplish this objective, recombinant StI (StIr) with a mutation in the membrane binding region has been employed. In this work, it was evaluated the impact of mutating tryptophan 111 to cysteine on the toxin pore forming capability. StI W111C is still able to permeabilize erythrocytes and liposomes, but at ten-fold higher concentration than StI. This is due to its lower affinity for the membrane, which corroborates the importance of residue 111 for the binding of actinoporins to the lipid bilayer. In agreement, other functional characteristics not directly associated to the binding, are essentially the same for both variants, that is, pores have oligomeric structures with similar radii, conductance, cation-selectivity, and instantaneous current-voltage behavior. In addition, this work provides experimental evidence sustaining the toroidal protein-lipid actinoporins lytic structures, since the toxins provoke the trans-bilayer movement (flip-flop) of a pyrene-labeled analogue of phosphatidylcholine in liposomes, indicating the existence of continuity between the outer and the inner membrane leaflet. Finally, our planar lipid membranes results have also contributed to a better understanding of the actinoporin's pore assembly mechanism. After the toxin binding and the N-terminal insertion in the lipid membrane, the pore assembly occurs by passing through different transient sub-conductance states. These states, usually 3 or 4, are due to the successive incorporation of N-terminal α-helices and lipid heads to the growing pores until a stable toroidal oligomeric structure is formed, which is mainly tetrameric.
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Affiliation(s)
- Valeria Antonini
- National Research Council of Italy - Institute of Biophysics and Bruno Kessler Foundation, Trento, Italy
| | - Victor Pérez-Barzaga
- Center for Protein Studies, Faculty of Biology, University of Havana, Vedado, Ciudad de La Habana, Cuba
| | - Silvia Bampi
- National Research Council of Italy - Institute of Biophysics and Bruno Kessler Foundation, Trento, Italy
| | - David Pentón
- Center for Protein Studies, Faculty of Biology, University of Havana, Vedado, Ciudad de La Habana, Cuba
| | - Diana Martínez
- Center for Protein Studies, Faculty of Biology, University of Havana, Vedado, Ciudad de La Habana, Cuba
| | - Mauro Dalla Serra
- National Research Council of Italy - Institute of Biophysics and Bruno Kessler Foundation, Trento, Italy
- * E-mail: (MDS); (MT)
| | - Mayra Tejuca
- Center for Protein Studies, Faculty of Biology, University of Havana, Vedado, Ciudad de La Habana, Cuba
- * E-mail: (MDS); (MT)
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67
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Leichenko EV, Monastirnaya MM, Zelepuga EA, Tkacheva ES, Isaeva MP, Likhatskaya GN, Anastyuk SD, Kozlovskaya EP. Hct-a is a new actinoporin family from the heteractis crispa sea anemone. Acta Naturae 2014; 6:89-98. [PMID: 25558399 PMCID: PMC4273096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Several new actinoporin isoforms with molecular weights of 18995.5 to 19398.7 Da exhibiting a high hemolytic activity were isolated from the tropical sea anemone Heteractis crispa using a combination of liquid chromatography techniques. The actinoporins were demonstrated to occur as mono-, di-, and trimers in aqueous solutions. The sequences of the genes encoding actinoporins were identified, and the amino acid sequences of the new polypeptides belonging to the Hct-A actinoporin family were obtained. The new acinoporins differ in their isoelectric points, the number and localization of charged amino acid residues at the functionally important N-terminal fragment of the molecule, as well as in the charge of a tetrapeptide (amino acid residues 74-77) involved in an electrostatic interaction with the cytoplasmic membrane. A recombinant actinoporin, rHct-A2, with a molecular weight of 19141 Da, pI of 9.64, and hemolytic activity of 4.0 × 104 HU/mg, was obtained. The conductivity of the ion channels formed by rHct-A2 in the BLM was demonstrated to be similar to that of the native actinoporin from H. crispa. The obtained data expand knowledge on the structural and functional relationships of actinoporins and contribute to our understanding of the functioning mechanism of these molecules, which is the basis for the development of compounds with a high biomedical potential. Currently, they are considered as models for obtaining antitumor, antibacterial, and cardiac-stimulating agents.
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Affiliation(s)
- E. V. Leichenko
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
| | - M. M. Monastirnaya
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
| | - E. A. Zelepuga
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
| | - E. S. Tkacheva
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
| | - M. P. Isaeva
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
| | - G. N. Likhatskaya
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
| | - S. D. Anastyuk
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
| | - E. P. Kozlovskaya
- Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, Vladivostok, 690022, Russia
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68
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Baker MAB, Rojko N, Cronin B, Anderluh G, Wallace MI. Photobleaching Reveals Heterogeneous Stoichiometry for Equinatoxin II Oligomers. Chembiochem 2014; 15:2139-45. [DOI: 10.1002/cbic.201300799] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Indexed: 01/19/2023]
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69
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Skočaj M, Resnik N, Grundner M, Ota K, Rojko N, Hodnik V, Anderluh G, Sobota A, Maček P, Veranič P, Sepčić K. Tracking cholesterol/sphingomyelin-rich membrane domains with the ostreolysin A-mCherry protein. PLoS One 2014; 9:e92783. [PMID: 24664106 PMCID: PMC3963934 DOI: 10.1371/journal.pone.0092783] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 02/25/2014] [Indexed: 01/01/2023] Open
Abstract
Ostreolysin A (OlyA) is an ∼15-kDa protein that has been shown to bind selectively to membranes rich in cholesterol and sphingomyelin. In this study, we investigated whether OlyA fluorescently tagged at the C-terminal with mCherry (OlyA-mCherry) labels cholesterol/sphingomyelin domains in artificial membrane systems and in membranes of Madin-Darby canine kidney (MDCK) epithelial cells. OlyA-mCherry showed similar lipid binding characteristics to non-tagged OlyA. OlyA-mCherry also stained cholesterol/sphingomyelin domains in the plasma membranes of both fixed and living MDCK cells, and in the living cells, this staining was abolished by pretreatment with either methyl-β-cyclodextrin or sphingomyelinase. Double labelling of MDCK cells with OlyA-mCherry and the sphingomyelin-specific markers equinatoxin II-Alexa488 and GST-lysenin, the cholera toxin B subunit as a probe that binds to the ganglioside GM1, or the cholesterol-specific D4 domain of perfringolysin O fused with EGFP, showed different patterns of binding and distribution of OlyA-mCherry in comparison with these other proteins. Furthermore, we show that OlyA-mCherry is internalised in living MDCK cells, and within 90 min it reaches the juxtanuclear region via caveolin-1-positive structures. No binding to membranes could be seen when OlyA-mCherry was expressed in MDCK cells. Altogether, these data clearly indicate that OlyA-mCherry is a promising tool for labelling a distinct pool of cholesterol/sphingomyelin membrane domains in living and fixed cells, and for following these domains when they are apparently internalised by the cell.
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Affiliation(s)
- Matej Skočaj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Nataša Resnik
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Maja Grundner
- Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katja Ota
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Nejc Rojko
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Vesna Hodnik
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Andrzej Sobota
- Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Peter Maček
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Peter Veranič
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
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70
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Piovesan AR, Martinelli AHS, Ligabue-Braun R, Schwartz JL, Carlini CR. Canavalia ensiformis urease, Jaburetox and derived peptides form ion channels in planar lipid bilayers. Arch Biochem Biophys 2014; 547:6-17. [PMID: 24583269 DOI: 10.1016/j.abb.2014.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 01/22/2023]
Abstract
Ureases catalyze the hydrolysis of urea into NH3 and CO2. They are synthesized by plants, fungi and bacteria but not by animals. Ureases display biological activities unrelated to their enzymatic activity, i.e., platelet and neutrophil activation, fungus inhibition and insecticidal effect. Urease from Canavalia ensiformis (jack bean) is toxic to several hemipteran and coleopteran insects. Jaburetox is an insecticidal fragment derived from jack bean urease. Among other effects, Jaburetox has been shown to interact with lipid vesicles. In this work, the ion channel activity of C. ensiformis urease, Jaburetox and three deletion mutants of Jaburetox (one lacking the N-terminal region, one lacking the C-terminal region and one missing the central β-hairpin) were tested on planar lipid bilayers. All proteins formed well resolved, highly cation-selective channels exhibiting two conducting states whose conductance ranges were 7-18pS and 32-79pS, respectively. Urease and the N-terminal mutant of Jaburetox were more active at negative potentials, while the channels of the other peptides did not display voltage-dependence. This is the first direct demonstration of the capacity of C. ensiformis urease and Jaburetox to permeabilize membranes through an ion channel-based mechanism, which may be a crucial step of their diverse biological activities, including host defense.
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Affiliation(s)
- Angela R Piovesan
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil
| | - Anne H S Martinelli
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil; Department of Biophysics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil
| | - Rodrigo Ligabue-Braun
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil
| | - Jean-Louis Schwartz
- Groupe d'étude des protéines membranaires (GÉPROM, FQR-S) and Department of Physiology, Faculty of Medicine, Université de Montréal, Montreal, Quebec H3C 3J7, Canada; Centre SÈVE (FQR-NT), Université de Sherbrooke, Sherbrooke, Quebec J1K 2R, Canada.
| | - Celia R Carlini
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil; Department of Biophysics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS CEP 91501-970, Brazil.
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71
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García-Linares S, Richmond R, García-Mayoral MF, Bustamante N, Bruix M, Gavilanes JG, Martínez-del-Pozo Á. The sea anemone actinoporin (Arg-Gly-Asp) conserved motif is involved in maintaining the competent oligomerization state of these pore-forming toxins. FEBS J 2014; 281:1465-1478. [DOI: 10.1111/febs.12717] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/12/2013] [Accepted: 12/31/2013] [Indexed: 01/19/2023]
Affiliation(s)
- Sara García-Linares
- Departamento de Bioquímica y Biología Molecular I; Facultad de Ciencias Químicas; Universidad Complutense; Madrid Spain
| | - Ryan Richmond
- Departamento de Bioquímica y Biología Molecular I; Facultad de Ciencias Químicas; Universidad Complutense; Madrid Spain
| | | | | | - Marta Bruix
- Instituto de Química-Física Rocasolano; Madrid Spain
| | - José G. Gavilanes
- Departamento de Bioquímica y Biología Molecular I; Facultad de Ciencias Químicas; Universidad Complutense; Madrid Spain
| | - Álvaro Martínez-del-Pozo
- Departamento de Bioquímica y Biología Molecular I; Facultad de Ciencias Químicas; Universidad Complutense; Madrid Spain
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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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