Figure 5. Proteasome activity is unchanged in lungs of LMP2 knockout mice. (A) Cleavage of luminogenic model substrates specific for the caspase-like (C-L), chymotrypsin-like (CT-L) or trypsin-like (T-L) active site of the proteasome in lung tissue lysate of LMP2−/− mice. n = 5-8+SEM. (B) Native gel analysis of proteasome complexes with activity overlay for CT-L activity in lung tissue lysate of LMP2−/− mice and (C) quantification thereof. Bar graphs show mean+SEM. (D) Western blot analysis for lysin-48 linked polyubiquitinated proteins in lung tissue lysates from young and aged LMP2−/− mice (E) and quantification thereof. β-Actin was used as a loading control.