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

Autor(es)

Crepaldi Domingues, Cleyton ^[1] ; Ciana, Annarita ^[2] ; Buttafava, Armando ^[3] ; Balduini, Cesare ^[2] ; de Paula, Eneida ^[1] ; Minetti, Giampaolo ^[2]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Journal of Membrane Biology; v. 227, n. 1, p. 39-48, JAN 2009.
• Citações Web of Science: 16

Resumo

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)

• Processo FAPESP: 03/02394-4 - Solubilização de lipídios e proteínas de membrana por tensoativos clássicos e não clássicos
• Beneficiário: Eneida de Paula
• Modalidade de apoio: Auxílio à Pesquisa - Regular