FIGURE 5.

Differential stability of wild-type WFS1 and various mutants. A, the C-terminal part of WFS1 is important for degradation by Smurf1. HEK293T cells were transfected with Smurf1 and deletion mutants of WFS1, and the cell lysates were analyzed by immunoblot analysis. B, shown is a half-life analysis of wild-type and mutant WFS1. Wild-type and the indicated WFS1 mutants were transfected into HEK293T cells, and the cells were treated with a 40 μg/ml cycloheximide chase for the indicated times. The half-lives of wild-type and WFS1 mutants were determined by Western blot. Data are the mean ± S.D. (n = 3). Quantitative analysis was performed by measuring integrated optical density using the program Gel-Pro analyzer. The exposure time of the Western blot analysis of certain mutants was adjusted to show a comparable expression level at time point zero (lane 1 of each group).