Figure 7.

DAB2 protein downregulation after TLR activation does not require proteasome or lysosomal degradation. (A) DAB2 (green) and EEA-1 or LAMP-1 (red) were immunolabeled in DC2.4 cells exposed to control medium or to 100 ng/mL LPS for 20 min and images were acquired using confocal microscopy. Arrows indicate cells undergoing mitosis. There was no co-localization of DAB2 with early endosomal (EEA-1) or lysosomal (LAMP-1) positive compartments. (B) DAB2 expression was assessed by western blotting in cells pre-treated with 2 μM MG132, 100 nM Bafilocymin A1 or DMSO (vehicle) in culture media for 30 min before 1 h treatment with 100 ng/mL LPS. (C) DAB2 expression was assessed by Western blotting in control cells, cells treated for 1 h with LPS, treated with 2 mM n-acetyl-cysteine (NAC) for 1 h, cells pre-treated 15 min with NAC before 1 h LPS treatment, or cells treated with 55 μM tert-butyl-hydroperoxide (TBHP) for 1 h. Data represents results from least three independent experiments.