Proteasome-mediated degradation of IκBα and processing of p105 in Crohn disease and ulcerative colitis
J. Clin. Invest. Alexander Visekruna, et al. 116:3195 doi:10.1172/JCI28804 [
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Figure 6Effect of immunoproteasomes on degradation of IκBα. (
A) Kinetics of IκBα degradation by 20S proteasomes purified from colonic mucosa of patients with IBD and controls (CD,
n = 5; UC,
n = 5; controls,
n = 5). IκBα was in vitro translated in the presence of
35S-methionine (Supplemental Figure 2) and incubated with isolated 20S proteasomes for indicated times. C60 represents a control incubated for 60 minutes without 20S proteasomes with an equivalent amount of IκBα. (
B) Quantitative evaluation of IκBα degradation by 20S proteasomes isolated from patients with IBD and controls in the absence of ATP.
P < 0.0001 (by 1-way ANOVA);
n = 5. (
C) Analysis of degradation of in vitro–translated IκBα by 2 different subsets of 20S proteasomes. Data from 1 representative experiment are shown for purified constitutive proteasomes (LCL 721.174;
n = 3) and immunoproteasomes (LCL 721;
n = 3). Lack of β1i and β5i in LCL 721.174 excludes the incorporation of immunosubunits in 20S proteasomes. C90 represents a control line without 20S proteasomes. (
D) Quantification of IκBα degradation by 20S protesomes isolated from LCL 721 and LCL 721.174 cells (
n = 3).
