Caracterización de dominios de membrana de eritrocitos resistentes a la extracción con el detergente zwitteriónico Chaps

RODI P; VELÁZQUEZ M; GENNARO AM

San Carlos de Bariloche

Otro; XXXII Reunión Anual de Sociedad Argentina de Biofísica; 2003

The usual approach to study membrane rafts, which are laterally segregated domains enriched in sphingolipids, cholesterol and specific proteins, involves isolation of detergent resistant membrane domains (DRM). In previous works we have obtained erythrocyte DRM using the non-ionic detergent Triton X-100, and characterized their protein pattern and lipid ordering. We showed that DRM could also be obtained from cholesterol depleted erythrocytes (Rivas and Gennaro, Chem. Phys. Lipids 122:165-9, 2003). In the present work, we investigate the effects of treating erythrocytes  with the zwitterionic detergent CHAPS. We obtained DRM both from intact and from cholesterol-depleted erythrocytes. However, a detergent/lipid rate larger than that used with Triton was needed in order to attain complete hemolysis. The insoluble material was characterized in lipid and protein composition by TLC and SDS-PAGE elerophoresis, and in lipid ordering by spin label EPR spectroscopy. The observed differences between these DRM and those extracted with Triton X-100 reinforce the hypothesis that DRM and rafts should not be considered as identical entities, as DRM characteristics depend on the methodology used in the extraction procedure.