Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers

Copyright © by Biophysical Society. Final full-text version of the paper available at: http://www.biophysj.org/cgi/content/abstract/90/3/903

Bibliographic Details
Authors: Sot, Jesús, Bagatolli, Luis A., Goñi, Félix M.
Format: article
Publication Date:2006
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/3538
Online Access:http://hdl.handle.net/10261/3538
Access Level:Open access
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spelling Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide BilayersSot, JesúsBagatolli, Luis A.Goñi, Félix M.Copyright © by Biophysical Society. Final full-text version of the paper available at: http://www.biophysj.org/cgi/content/abstract/90/3/903When cell membranes are treated with Triton X-100 or other detergents at 4 C, a nonsolubilized fraction can often be recovered, the ‘‘detergent-resistant membranes’’, that is not found when detergent treatment takes place at 37 C. Detergentresistant membranes may be related in some cases to membrane ‘‘rafts’’. However, several basic aspects of the formation of detergent-resistant membranes are poorly understood. To answer some of the relevant questions, a simple bilayer composition that would mimic detergent-resistant membranes was required. The screening of multiple lipid compositions has shown that the binary mixture egg sphingomyelin/egg ceramide (SM/Cer) exhibits the required detergent resistance. In detergent-free membranes composed of different mixtures of SM and Cer (5–30 mol % of Cer) differential scanning calorimetry, fluorescence spectroscopy, and fluorescence microscopy experiments reveal the presence of discrete, Cer-enriched gel domains in a broad temperature range. In particular, at temperatures below SM phase transition ( 40 C) two gel (respectively Cer-rich and SM-rich) phases are directly observed using fluorescence microscopy. Although pure SM membranes are fully solubilized by Triton X-100 at room temperature, 5 mol % Cer is also enough to induce detergent resistance, even with a large detergent excess and lengthy equilibration times. Short-chain Cers do not give rise to detergent resistance. SM/Cer mixtures containing up to 30 mol % Cer become fully soluble at ;50 C, i.e., well above the gel-fluid transition temperature of SM. The combined results of temperaturedependent solubilization and differential scanning calorimetry reveal that SM-rich domains are preferentially solubilized over the Cer-rich ones as soon as the former melt (i.e., at ;40 C). As a consequence, at temperatures allowing only partial solubilization, the nonsolubilized residue is enriched in Cer with respect to the original bilayer composition. Fluorescence microscopy of giant unilamellar vesicles at room temperature clearly shows that SM-rich domains are preferentially solubilized over the Cer-rich ones and that the latter become more rigid and extensive as a consequence of the detergent effects. These observations may be relevant to the phenomena of sphingomyelinase-dependent signaling, generation of ‘‘raft platforms’’, and detergent-resistant cell membranes.This work was supported in part by grants from the Spanish Ministerio de Educación y Ciencia (No. BFU 2004-02955 to F.M.G., and No. BMC 2002-00784 to A.A.), and the University of the Basque Country (UPV00042.310/13552 to F.M.G.). Research in the laboratory of LAB is funded by a grant from the Danish Natural Science Research Council (SNF) (21-03-0569) and the Danish National Research Foundation (which supports MEMPHYS-Center for Biomembrane Physics). J.S. is a graduate student supported by the Basque government.Peer reviewedBiophysical Society200820082006info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501390356 bytesapplication/pdfhttp://hdl.handle.net/10261/3538reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglésinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/35382026-05-22T06:33:51Z
dc.title.none.fl_str_mv Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
title Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
spellingShingle Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
Sot, Jesús
title_short Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
title_full Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
title_fullStr Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
title_full_unstemmed Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
title_sort Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
dc.creator.none.fl_str_mv Sot, Jesús
Bagatolli, Luis A.
Goñi, Félix M.
author Sot, Jesús
author_facet Sot, Jesús
Bagatolli, Luis A.
Goñi, Félix M.
author_role author
author2 Bagatolli, Luis A.
Goñi, Félix M.
author2_role author
author
description Copyright © by Biophysical Society. Final full-text version of the paper available at: http://www.biophysj.org/cgi/content/abstract/90/3/903
publishDate 2006
dc.date.none.fl_str_mv 2006
2008
2008
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/3538
url http://hdl.handle.net/10261/3538
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 390356 bytes
application/pdf
dc.publisher.none.fl_str_mv Biophysical Society
publisher.none.fl_str_mv Biophysical Society
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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