Figure 1.

Simplified overview of APP processing. The amyloidogenic APP processing pathway (right) initially generates β-C-terminal fragments (β-CTF) by β-secretase cleavage. Further cleavage by γ-secretase leads to the release of Aβ peptides and the generation of the AICD fragment (B). Alternatively, initial cleavage by α-secretase precludes Aβ generation, thereby releasing sAPPα and producing α-CTFs. Subsequent γ-secretase cleavage releases the P3 fragment and also liberates the intracellular AICD fragment (A).