Figure 3.

SCP4 prevents polyubiquitination and promotes stability of Snail. (a) SCP4 enhances Snail stabilization. HEK293T cells were co-transfected with FLAG–Snail and a FLAG tagged phosphatase. After 48 h later, cells were treated with or without MG132 for 6 h. The protein level of Snail was detected by western blotting analysis (b). SCP4 stabilizes Snail in a dosage-dependent manner. HEK293T cells were co-transfected with equal amount of FLAG–Snail and an increased dosage of SCP4 or SCP4DN. After 48 h, cells were treated with MG132 for 6 h. Whole cell lysates were harvested for western blotting analysis. (c) SCP4 inhibits Snail ubiquitination. HEK293T cells were co-transfected with HA–Snail, His-Myc-Ub and FLAG–SCP4/DN. After 48 h, cells were treated with or without MG132 for 6 h. Cells were lysed by RIPA lysis buffer and Snail was immunoprecipitated by anti-HA antibody.