| Equinatoxin II permeabilizing activity depends on the presence of sphingomyelin and lipid phase coexistence. | |
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MedLine Citation:
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PMID: 18390598 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Equinatoxin II is a pore-forming protein of the actinoporin family. After membrane binding, it inserts its N-terminal alpha-helix and forms a protein/lipid pore. Equinatoxin II activity depends on the presence of sphingomyelin in the target membrane; however, the role of this specificity is unknown. On the other hand, sphingomyelin is considered an essential ingredient of lipid rafts and promotes liquid-ordered/liquid-disordered phase separation in model membranes that mimic raft composition. Here, we used giant unilamellar vesicles to simultaneously investigate the effect of sphingomyelin and phase separation on the membrane binding and permeabilizing activity of Equinatoxin II. Our results show that Equinatoxin II binds preferentially to the liquid-ordered phase over the liquid-disordered one and that it tends to concentrate at domain interfaces. In addition, sphingomyelin strongly enhances membrane binding of the toxin but is not sufficient for membrane permeabilization. Under the same experimental conditions, Equinatoxin II formed pores in giant unilamellar vesicles containing sphingomyelin only when liquid-ordered and -disordered phases coexisted. Our observations demonstrate the importance of phase boundaries for Equinatoxin II activity and suggest a double role of sphingomyelin as a specific receptor for the toxin and as a promoter of the membrane organization necessary for Equinatoxin II action. |
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Authors:
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Peter Schön; Ana J García-Sáez; Petra Malovrh; Kirsten Bacia; Gregor Anderluh; Petra Schwille |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2008-04-04 |
Journal Detail:
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Title: Biophysical journal Volume: 95 ISSN: 1542-0086 ISO Abbreviation: Biophys. J. Publication Date: 2008 Jul |
Date Detail:
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Created Date: 2008-06-27 Completed Date: 2008-07-25 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0370626 Medline TA: Biophys J Country: United States |
Other Details:
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Languages: eng Pagination: 691-8 Citation Subset: IM |
Affiliation:
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Biophysics Group, BIOTEC, TU Dresden, Dresden, Germany. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Cnidarian Venoms
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chemistry* Lipid Bilayers / chemistry* Permeability Phase Transition Sphingomyelins / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Cnidarian Venoms; 0/Lipid Bilayers; 0/Sphingomyelins; 54578-46-0/equinatoxin |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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