Figure 8. Inhibition of IbeA+ E. coli K1-induced proteasomal degradation by knockdown of vimentin and VH domain deletion.

Immunoblotting analysis of polyubiquitinylated proteins (Ub-prs): (A) HBMECs with siRNA-mediated knockdown of vimentin; and (B) HBMECs transduced with the lentivirus constructs expressing GFP–VRT and GFP. In both (A) and (B), all the cells were incubated with or without E. coli K1 strains (E44 and ZD1, 10⁷/ml) for 2 h. The Ub-prs were detected in cytoplasmic fractions to determine the proteasomal degradation as described in Materials and Methods. β-actin was used as an internal loading control. In all experiments, untreated HBMECs (UNT) were taken as controls.