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. Author manuscript; available in PMC: 2014 Jul 5.
Published in final edited form as: Chem Biol Interact. 2013 May 14;204(2):116–124. doi: 10.1016/j.cbi.2013.04.016

Figure 4. Prolonged proteasomal inhibition by MG132 stimulated time-dependent autophagic flux.

Figure 4

(A) N27 cells were confirmed to be autophagy-competent. LC3 II accumulation is a marker for autophagosome formation. (B) The representative immunoblot shows autophagy induction following treatment with MG132 (1μM). (C) Significant accumulation of LC3 II could be detected at 4h and to a greater extent at 24h. Fold changes of LC3 II levels are normalized by control and estimated by densitometry. These data are presented as mean ± SD, (n=3); **p<0.01 and ***p<0.001 are considered significant by ANOVA using Dunnet’s multiple comparison test. (D) Induction of autophagy by MG132 was confirmed by co-incubation with chloroquine (CQ). Cells were exposed to MG132 (1μM) with or without the co-treatment of CQ for the indicated times and then processed for immunoblot analysis. Note that CQ is a specific lysosome inhibitor and could suppress the fusion of autophagosomes with lysosomes. The elevated levels of LC3 II in the presence of CQ (>4h) excluded the possibility that MG132 stimulated autophagic flux was due to the blockade of autophagic degradation in N27 cells.