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Article Dans Une Revue Biochimica et Biophysica Acta:Biomembranes Année : 2007

Cholesterol modulation of membrane resistance to Triton-X100 explored by atomic force microscopy.

K. El Kirat
S. Morandat

Résumé

Biomembranes are not homogeneous, they present a lateral segregation of lipids and proteins which leads to the formation of detergent-resistant domains, also called “rafts”. These rafts are particularly enriched in sphingolipids and cholesterol. Despite the huge body of literature on raft insolubility in non-ionic detergents, the mechanisms governing their resistance at the nanometer scale still remain poorly documented. Herein, we report a real-time atomic force microscopy (AFM) study of model lipid bilayers exposed to Triton X-100 (TX-100) at different concentrations. Different kinds of supported bilayers were prepared with dioleoylphosphatidylcholine (DOPC), sphingomyelin (SM) and cholesterol (Chol). The DOPC/SM 1:1 (mol/mol) membrane served as the non-resistant control, and DOPC/SM/Chol 2:1:1 (mol/mol/mol) corresponded to the raft-mimicking composition. For all the lipid compositions tested, AFM imaging revealed that TX-100 immediately solubilized the DOPC fluid phase leaving resistant patches of membrane. For the DOPC/SM bilayers, the remaining SM-enriched patches were slowly perforated leaving crumbled features reminiscent of the initial domains. For the raft model mixture, no holes appeared in the remaining SM/Chol patches and some erosion occurred. This work provides new, nanoscale information on the biomembranes' resistance to the TX-100-mediated solubilization, and especially about the influence of Chol.

Domaines

Biomatériaux

Dates et versions

hal-00192568 , version 1 (28-11-2007)

Identifiants

Citer

K. El Kirat, S. Morandat. Cholesterol modulation of membrane resistance to Triton-X100 explored by atomic force microscopy.. Biochimica et Biophysica Acta:Biomembranes, 2007, 1768, pp.2300-2309. ⟨10.1016/j.bbamem.2007.05.006⟩. ⟨hal-00192568⟩
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