Figure 5: Only aloe-emodin promotes the dissociation of HSP90/ERα and subsequent ERα ubiquitination. The interaction between ERα and HSP90 in MCF-7 cells following 25 μM treatment of aloe-emodin (a) or emodin (b) in the presence of MG132 (5 μM) for 24 h was evaluated by ERα immunoprecipitation followed by western blotting for HSP90 with specific antibodies. The ubiquitin-conjugated ERα levels in MCF-7 cells following 25 μM treatment of aloe-emodin (c) and emodin (d) in the presence of MG132 (5 μM) were examined by immunoprecipitation with anti-ERα or antiubiquitin antibodies followed by western blotting. The lysates were used in the western blotting experiments to indicate protein levels. Immunoprecipitation by IgG served as a negative control. β-Actin served as an internal control for western blotting. The quantitative data were obtained from the results of three times immunoprecipitation experiments and presented as fold change of control. The quantitative graphs were presented as the mean SEM. * and ** correspond to and , respectively, versus the control group.