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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Resistance of Human Erythrocyte Membranes to Triton X-100 and C12E8

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Author(s):
Crepaldi Domingues, Cleyton [1] ; Ciana, Annarita [2] ; Buttafava, Armando [3] ; Balduini, Cesare [2] ; de Paula, Eneida [1] ; Minetti, Giampaolo [2]
Total Authors: 6
Affiliation:
[1] Univ Estadual Campinas, Inst Biol, Dept Bioquim, Campinas, SP - Brazil
[2] Univ Pavia, Dipartimento Biochim A Castellani, I-27100 Pavia - Italy
[3] Univ Pavia, Dipartimento Chim Gen, I-27100 Pavia - Italy
Total Affiliations: 3
Document type: Journal article
Source: Journal of Membrane Biology; v. 227, n. 1, p. 39-48, JAN 2009.
Web of Science Citations: 16
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 C(12)E(8). 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 C(12)E(8), 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 C(12)E(8) in comparison to intact cells, while the difference in the S values between Triton X-100 and C(12)E(8) 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 C(12)E(8) detergent, protein content is dissimilar, with flotillin-2 being selectively enriched in Triton X-100 DRMs. (AU)