Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/70987
Type: Artigo de periódico
Title: Resistance of Human Erythrocyte Membranes to Triton X-100 and C12E8
Author: Crepaldi Domingues, C
Ciana, A
Buttafava, A
Balduini, C
de Paula, E
Minetti, G
Abstract: Lipid rafts are microdomains enriched in cholesterol and sphingolipids that contain specific membrane proteins. The resistance of domains to extraction by nonionic detergents at 4A degrees C is the commonly used method to characterize these structures that are operationally defined as detergent-resistant membranes (DRMs). Because the selectivity of different detergents in defining membrane rafts has been questioned, we have compared DRMs from human erythrocytes prepared with two detergents: Triton X-100 and C12E8. The DRMs obtained presented a cholesterol/protein mass ratio three times higher than in the whole membrane. Flotillin-2 was revealed in trace amounts in DRMs obtained with C12E8, but it was almost completely confined within the DRM fraction with Triton X-100. Differently, stomatin was found distributed in DRM and non-DRM fractions for both detergents. We have also measured the order parameter (S) of nitroxide spin labels inserted into DRMs by means of electron paramagnetic resonance. The 5- and 16-stearic acid spin label revealed significantly higher S values for DRMs obtained with either Triton X-100 or C12E8 in comparison to intact cells, while the difference in the S values between Triton X-100 and C12E8 DRMs was not statistically significant. Our results suggest that although the acyl chain packing is similar in DRMs prepared with either Triton X-100 or C12E8 detergent, protein content is dissimilar, with flotillin-2 being selectively enriched in Triton X-100 DRMs.
Subject: Detergent-resistant membrane
Lipid raft
Membrane-skeleton
EPR
Nitroxide spin label
Flotillin
Country: EUA
Editor: Springer
Rights: fechado
Identifier DOI: 10.1007/s00232-008-9142-4
Date Issue: 2009
Appears in Collections:Unicamp - Artigos e Outros Documentos

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