Figure 2.

Molecular basis for AD and interaction with neurogenesis in the adult hippocampus. In the non-amyloidogenic pathway, APP is processed by α-secretase that cleaves within the Aβ domain. sAPPα and a membrane-bound carboxyl-terminal fragment are generated. In the amyloidogenic pathway, APP is sequentially cleaved by β- and γ-secretases to release the neurotoxic Aβ peptide. β-secretase cleavage of APP forms a secreted ectodomain sAPPβ and a membrane-bound fragment. Cleavage of the latter product generates AICD and Aβ. Suggested functions of relevant signal molecules in adult hippocampal neurogenesis are summarized.