Control of Cellular Bcl-xL Levels by Deamidation-Regulated Degradation
Figure 4
Deamidation targets Bcl-xL for degradation.
(A) Immunoblot of endogenous Bcl-xL, Bcl-2, and tubulin from SAOS-2 cells that were treated with 10 µM of etoposide for the indicated times. (B) Immunoblot of endogenous Bcl-xL and tubulin in SAOS-2 cells that were treated with 10 µg/ml of cycloheximide for the indicated times. (C) Immunoblot of Bcl-xL and tubulin in bcl-x−/−/p53−/− MEFs expressing wild-type Bcl-xL and a form of Bcl-xL in which deamidation is disrupted by substitution of alanines for the two susceptible asparagines, Bcl-xL(N52A/N66A). The cells were treated with 5 µM of etoposide for the indicated times or with the indicated concentration of cisplatin. (D) Survival assays of bcl-x−/−/p53−/− MEFs expressing Bcl-xL(N52A/N66A) and wild-type Bcl-xL. MEFs were treated with etoposide and cisplatin and assessed for apoptosis after 72 h.