Figure 2.

α-hemolysin expression in E. coli enhances platelet proteasome activation. (A) Platelet proteasome activity was enhanced upon incubation (4 h) with α-hemolysin expressing E. coli (UTI89 WT), whereas incubation with E. coli lacking functional α-hemolysin (UTI89 ΔhlyA) showed a trend towards less proteasome activation, as assessed by fluorescent peptide cleavage (*p < 0.05, n = 5). (B) The proteasome substrate Talin-1 was increasingly cleaved during coincubation with E. coli (UTI89) (ratio of 190 kDa to 235 kDa fragments) compared to control platelets. Increase of cleavage was less with the α-hemolysin negative strain UTI89 ΔhlyA compared to platelet control (n = 2).