FIG. 1.

RK-BARF0 induces proteasome-dependent degradation of Notch. (A) H1299 cells were transiently transfected with combinations of myc-tagged Notch4 and full-length His6-tagged RK-BARF0 or a mutant encoding the first 158 amino acids of RK-BARF0 (RK-158), which cannot bind Notch. Expression was induced with 5 μM CdCl₂, and the samples were treated with DMSO or 20 μM MG132. Notch4 was detected by immunoblot with α-myc. (B) BJAB stable cells expressing full-length His6-tagged RK-BARF0, RK-158, or the first 179 amino acids of RK-BARF0 (RK-179) were induced with 5 μM CdCl₂ and immunoblotted with α-His6 to detect RK-BARF0 (top panel) or α-Notch1 to detect endogenous Notch1 (bottom panel).