Proteasome inhibition did not change expression levels of LONP1 but caused a reduction of UCP2 and VDAC1 protein in neuronal cells. A, B: Representative Western blot images of LONP1, UCP2 and VDAC1 after 100 nM BTZ and CFZ treatment for 3 and 24 h in human neuronal cells. C-E: Quantification of LONP1, UCP2 and VDAC1 after 100 nM BTZ and CFZ treatment for 3 and 24 h in human neuronal cells. Data represent means ± SEM, n = 3–4, *p < 0.05 versus control group.