Figure 4.

Inhibition of caveolar/lipid raft-mediated endocytosis does not block internalization of junctional proteins in calciumdepleted cells. T84 cells were preincubated for 60 min in serum-free T84 medium with either cholesterol oxidase (2 units/ml) or MβCD (10 mM) followed by a 120-min incubation in serum-free S-MEM containing the same concentrations of inhibitors. Control monolayers were incubated for the indicated times in serum-free T84 medium and S-MEM. Localization of E-cadherin and occludin was determined by immunofluorescence labeling and confocal microscopy. The bottom panel is a positive control, an effect of the inhibitors on cholera toxin uptake. As can be seen, both inhibitors attenuate cholera toxin uptake but fail to prevent internalization of junctional proteins.