English   español  
Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/3538
Compartir / Impacto:
Estadísticas
Add this article to your Mendeley library MendeleyBASE
Citado 89 veces en Web of Knowledge®  |  Pub MebCentral Ver citas en PubMed Central  |  Ver citas en Google académico
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar otros formatos: Exportar EndNote (RIS)Exportar EndNote (RIS)Exportar EndNote (RIS)
Título : Detergent-Resistant, Ceramide-Enriched Domains in Sphingomyelin/Ceramide Bilayers
Autor : Sot, Jesús; Bagatolli, Luis A.; Goñi, Félix M.
Fecha de publicación : 1-feb-2006
Editor: Biophysical Society
Citación : Biophys J. 2006 February 1; 90(3): 903–914
Resumen: When 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.
Descripción : Copyright © by Biophysical Society. Final full-text version of the paper available at: http://www.biophysj.org/cgi/content/abstract/90/3/903
URI : http://hdl.handle.net/10261/3538
DOI: 10.1529/biophysj.105.067710
ISSN: 1542-0086
Aparece en las colecciones: (UBF) Artículos
Ficheros en este ítem:
Fichero Descripción Tamaño Formato  
picrender.pdf381,21 kBAdobe PDFVista previa
Visualizar/Abrir
Mostrar el registro completo
 



NOTA: Los ítems de Digital.CSIC están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.