(A) The effects of GAPDH on degradation of Htt-552. The isolated lysosomes were incubated with 10 µg GAPDH and Htt-552 for 30 min at 37°C. At the end of the incubation, lysosomes were collected by centrifugation and the levels Htt-552 were determined with immunoblotting. Values are the mean±SE of three experiments. **P<0.01, *P<0.05 (compared with Htt-552-18Q without lysosomes); ##P<0.01, #P<0.05 (compared with Htt-552-100Q without lysosomes); $$P<0.01 (compared with Htt-552-18Q without GAPDH); P0.01 (compared with Htt-552-100Q without GAPDH). 