Fig. 5: Reduced synaptic proteasome activity in the APP/PS1 hippocampus.

Hippocampi from 12-month-old APP/PS1 mice or WT littermates were harvested for isolation of synaptosomes. a–c Proteasomal chymotrypsin-, trypsin-, and caspase-like activities were measured (chymotrypsin: n = 14 WT and 12 APP/PS1 for synaptosome, n = 17 WT and 12 APP/PS1 for cytosol; trypsin: 19 WT synaptosome, 17 APP/PS1 synaptosome, 21 WT cytosol, 17 APP/PS1 cytosol; caspase-like: 15 WT synaptosome, 12 APP/PS1 synaptosome, 17 WT cytosol, 13 APP/PS1 cytosol); two-tailed unpaired Student’s t test). d, e Proteasome 20S subunit α1 and 19S subunit Rpt6 were determined by Western blotting in synaptosome (d) (n = 7 WT and 6 APP/PS1; two-tailed unpaired Student’s t test) or cytosolic fractions (e) (n = 6 for all; two-tailed unpaired Student’s t test). Data are presented as mean ± SEM.