Which membrane properties determine detergent resistance?

TRUCCO, VM; RODI, PM; GENNARO, AM

Montevideo, Uruguay

Congreso; 6th International Conference on Biological Physics, XXVI Reunión Anual de la Sociedad Argentina de Biofísica and 5th Southern Cone Biophysics Congress; 2007

Many works support the existence of sphingolipid- and sterol-enriched microdomains, known as lipid rafts, in the plasma membrane. The detergent solubilization of cell membranes may be a powerful tool to obtain more insight about this issue. In this work, we study four different membrane systems: intact human and bovine erythrocytes, and human and bovine erythrocytes depleted in cholesterol with methyl-β-cyclodextrin. Each system was put under the action of different concentrations of the non ionic detergent Triton X-100, and the insoluble fraction was characterized by determining cholesterol and phosphorus content. A detergent resistance parameter was defined from the fit of the solubility curves. We measured the degree of acyl chain rigidity of the original membranes at different depth levels by EPR spectroscopy, and correlated this property, together with the contents of cholesterol and sphingomyelin,  to the detergent resistance parameter