Figure 1.

Proteolytic processing of APP. Proteolysis of APP by α-secretase or β-secretase leads to the secretion of αAPPs or βAPPs. Both secretases generate C-terminal fragments (CTF) of 10 kDa and 12 kDa respectively, which are inserted in the membrane (grey). These fragments can be cut by γ-secretase to release the peptides P3 and Aβ. Two further cleavage sites, termed ε and ζ, have been identified in the CTF.