Figure 9. Chronic treatment with a proteasome inhibitor replicates effects of POH1 depletion on ErbB2.

HeLa cells were incubated with epoxomicin (8 nM or 10 nM) or DMSO for 48 hours (fresh inhibitors were applied at 24 hours). Cell lysates obtained by “hot lysis” were subjected to SDS-PAGE followed by immunoblotting with ErbB2, EGFR, TrfR, POH1, and tubulin antibodies. Epoxomicin treatment resulted in the apparent loss of ErbB2 and concomitant appearance of a high molecular weight smear.