SAK3 administration rescues the decrease in proteasome activity in NL-G-F mice. (A) Proteasome activity assay using the fluorogenic peptides Suc-LLVY-AMC (chymotrypsin-like); (B) Bz-VGR-AMC (trypsin-like), and (C) Z-LLE-AMC (caspase-like) using brain homogenates from the cortical region (n = 7–8 per group); Suc-LLVY-AMC: F (3, 27) = 4.814, p < 0.01; Bz-VGR-AMC: F (3, 27) = 4.555, p < 0.05; Z-LLE-AMC: F (3, 27) = 5.795, p < 0.01. Error bars represent standard error of the mean (SEM). * p < 0.05, ** p < 0.01 vs. vehicle-treated WT mice; # p < 0.05 vs. vehicle-treated NL-G-F mice. The symbols (solid dots, squares, triangles and inverted triangle) indicate the individual values.