Fig. 5.

Abundance of endogenous SM submicrometric domains depends on membrane cholesterol. A: Moderate cholesterol depletion strongly decreases endogenous SM domain abundance. RBCs were treated in suspension with the indicated mβCD concentrations (∼75% residual cholesterol at 0.25 mM), then incubated with lysenin*, attached-spread onto poly-L-lysine-coverslips, and observed by confocal microscopy at identical settings in all conditions. Scale bars, 2 μm. Representative of six independent experiments. For views with multiple cells, see supplementary Fig. V. B: Moderate cholesterol depletion does not affect ¹²⁵I-lysenin* binding to RBCs. RBCs were either kept untreated (open bar) or depleted in cholesterol by 0.25 mM mβCD (filled bar) prior to labeling by ¹²⁵I-lysenin* mixed with cold lysenin* as in Fig. 1C. After washing, ¹²⁵I-lysenin* bound to RBCs was expressed as the percentage of control and presented as mean ± SEM.