Figure 5.

Activation of GTP-binding proteins by GTPγS prevents redistribution of CD44 and annexin II upon depletion of plasma membrane cholesterol by digitonin. Confocal vertical (x-z) sections of digitonin-treated EpH4 cells are shown. In filter-grown cells subjected to cholesterol depletion and semipermeabilization with digitonin, both CD44 (A) and annexin II (B) could be found at the apical surface after fixation and respective antibody staining. However, when GTPγS was added to the permeabilization buffer, neither CD44 (D) nor annexin II (E) underwent redistribution, but remained colocalized at the basolateral cell membrane domain. Merged images are shown in C and F. Bar, 10 μm.