Biological function of Presenilin and its role in AD pathogenesis

Presenilins (PSs) are the catalytic core of gamma-secretase complex. However, the mechanism of FAD-associated PS mutations in AD pathogenesis still remains elusive. Here we review the general biology and mechanism of gamma-secretase and focus on the catalytic components - presenilins and their biological functions and contributions to the AD pathogenesis. The functions of presenilins are divided into gamma-secretase dependent and gamma-secretase independent ones. The gamma-secretase dependent functions of presenilins are exemplified by the sequential cleavages in the processing of APP and Notch; the gamma-secretase independent functions of presenilins include stabilizing beta-catenin in Wnt signaling pathway, regulating calcium homeostasis and their interaction with synaptic transmission.