The effect of proteasome inhibitor on p62 phosphorylation in a shorter time. (a) SH-SY5Y cells were treated with Baf or Epo for the indicated times. Simultaneously, proteasomal activity was assessed. Immunoblotting analysis shows that both inhibitors induced the phosphorylation of S349 in a similar to HeLa cell. (b) A proteasomal activity assay shows that Epo inhibits trypsin-like, chymotrypsin-like and caspase-like activities of the proteasome in a time-dependent manner. While, Baf inhibits these activities in the first 30 minutes, and thereafter their activities returns to the basal levels.