Figure 5.

BikDD is degraded via both ubiquitination-dependent and -independent pathways. Lysine mutations and N-terminal tag fusion of BikDD were constructed to block potential ubiquitination sites. A. WT, mutant, and tagged BikDD-expressing MDA-MB-231 cells were treated with cycloheximide (CHX; 50 µg/ml) for the indicated time, and lysates were subjected to Western blot analysis with antibodies against Bik or internal control (α-tubulin). B. MDA-MB-231 cells expressing various forms of BikDD were treated with MG132 (10 µM) for 8 hours. Cell lysates were subjected to Western blot analysis with the indicated antibodies.