Western blots were probed with rabbit anti-APP polyclonal antibody (1:2000 dilutions, Sigma, St Louis, MO) overnight at 4 °C. This antibody was raised against a synthetic peptide corresponding to the C-terminal of human APP695 (amino acids 676–695). Since this sequence is identical in rat and mouse APP695 and in the isoforms APP751 and APP770, this antibody recognizes human, rat and mouse APP695, APP751 and APP770.