Figure 3.

The ubiquitin (Ub)–proteasome pathway was involved in celastrol (Cel)-induced mTOR downregulation.

Notes: MCF7 cells were treated with 5 µM Cel alone or combined with 15 µM MG132 (A) or 50 µM chloroquine (CQ) (B) for 24 hours. Cell extracts were subjected to Western blotting analysis. (C) MDA-MB231 cells were treated with 2.5 µM Cel alone or combined with 15 µM MG132 for 24 hours, and then subjected to Western blotting analysis. (D, E) MCF7 cells were transfected with the vector expressing Flag-mTOR for 40 hours, and then treated with 5 µM Cel for the indicated time (D) or treated with 15 µM MG132 alone/combined with 5 µM Cel (E). Cell extracts were immunoprecipitated (IP) with anti-Flag resin, and precipitated proteins and whole-cell extracts (WCE) were immunoblotted with the indicated antibodies.

Abbreviation: DMSO, dimethyl sulfoxide.