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. 2020 Sep 25;10:15765. doi: 10.1038/s41598-020-71550-5

Figure 1.

Figure 1

Degradation of ubiquitinated proteins by the standard proteasome (SP), the intermediate proteasome β5i (SIP), the intermediate proteasome β1i–β5i (DIP) and the immunoproteasome (IP). (a) p21 and (b) c-myc are degraded in a proteasome and ubiquitin-dependent manner. Western blot analysis of lysates of 293 SP cells treated or not with cycloheximide (CHX) alone or in combination with MLN7243, an inhibitor of the ubiquitin-activating enzyme, or with MG132 or bortezomib, two proteasome inhibitors. Cells were treated with MLN7243, MG132 or Bortezomib 30 min prior to the 5 h treatment with cycloheximide. (c, d) Western blot analysis of the kinetics of degradation of (c) p21 and (d) c-myc in 293 cell lines expressing the different proteasome subtypes. (e, f) Densitometric evaluation of the kinetics of the degradation of (e) p21 and (f) c-myc in the four different cell lines. All values (+ SD) are collected from three independent experiments. Full-length images for (a-d) are presented in Fig. S10.