(a) Starvation-induced long-lived protein degradation is impaired after NRBF2 knockdown. Compared with control (con) siRNA, NRBF2 siRNA decreases long-lived protein degradation (proteolysis rate) in NIH3T3 cells under starvation (ST) condition. This difference is diminished when the starved cells are co-treated with wortmannin (WM, 100 nM). (Data are shown as mean±s.e.m., P values are indicated on the figures, one-way analysis of variance with Dunnett as post hoc test, n=4; NS, not significant). 