Título:
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Caveolin-1-mediated apolipoprotein A-I membrane binding sites are not required for cholesterol efflux
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Autor/a:
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Le Lay, Soazig; Rodriguez, Macarena; Jessup, Wendy; Rentero Alfonso, Carles; Li, Qiong; Cartland, Siân; Grewal, Thomas; Gaus, Katharina
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Otros autores:
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Universitat de Barcelona |
Abstract:
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Caveolin-1 (Cav1), a structural protein required for the formation of invaginated membrane domains known as caveolae, has been implicated in cholesterol trafficking and homeostasis. Here we investigated the contribution of Cav1 to apolipoprotein A-I (apoA-I) cell surface binding and intracellular processing using mouse embryonic fibroblasts (MEFs) derived from wild type (WT) or Cav1-deficient (Cav1−/−) animals. We found that cells expressing Cav1 have 2.6-fold more apoA-I binding sites than Cav1−/− cells although these additional binding sites are not associated with detergent-free lipid rafts. Further, Cav1-mediated binding targets apoA-I for internalization and degradation and these processes are not correlated to cholesterol efflux. Despite lower apoA-I binding, cholesterol efflux from Cav1−/− MEFs is 1.7-fold higher than from WT MEFs. Stimulation of ABCA1 expression with an LXR agonist enhances cholesterol efflux from both WT and Cav1−/− cells without increasing apoA-I surface binding or affecting apoA-I processing. Our results indicate that there are at least two independent lipid binding sites for apoA-I; Cav1-mediated apoA-I surface binding and uptake is not linked to cholesterol efflux, indicating that membrane domains other than caveolae regulate ABCA1-mediated cholesterol efflux. |
Materia(s):
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-Colesterol -Membranes cel·lulars -Cholesterol -Cell membranes |
Derechos:
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cc-by (c) Le Lay, Soazig et al., 2011
http://creativecommons.org/licenses/by/3.0/es |
Tipo de documento:
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Artículo Artículo - Versión publicada |
Editor:
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Public Library of Science (PLoS)
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Compartir:
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