(E) Effects of starvation for 6 or 12 h on the degradation of Htt-552 in PC12 cells. The effects of these starvations on protein levels of Htt-552 protein were determined with Western blot analysis. Values are the mean±SE of three independent experiments. **P<0.01 (compared with Htt-552-18Q without treatment); ##P<0.01, #P<0.05 (compared with Htt-552-100Q without treatment). 