The paper by Doglio et al. has important implications for both the biological functions of the presenilin (PS) complex and the mechanisms by which PS FAD mutations promote neurodegeneration and other structural abnormalities in AD. The paper verifies previous results that presenilins regulate the PI3K/Akt cell survival pathway through a mechanism that is independent of the γ-secretase activity (Baki et al., 2004). This report is also consistent with recent evidence that FAD mutations may promote cell death and AD-related tau overphosphorylation through a mechanism that involves loss of presenilin function in the PI3K/Akt/GSK3 and other cell signaling pathways (Baki et al., 2004; Kang et al., 2005). This last concept is in contrast to the widely held view that FAD mutations cause a gain of presenilin γ-secretase function thus increasing production of neurotoxic species like Aβ1-42 (see, however,   Read more

The paper by Doglio et al. has important implications for both the biological functions of the presenilin (PS) complex and the mechanisms by which PS FAD mutations promote neurodegeneration and other structural abnormalities in AD. The paper verifies previous results that presenilins regulate the PI3K/Akt cell survival pathway through a mechanism that is independent of the γ-secretase activity (Baki et al., 2004). This report is also consistent with recent evidence that FAD mutations may promote cell death and AD-related tau overphosphorylation through a mechanism that involves loss of presenilin function in the PI3K/Akt/GSK3 and other cell signaling pathways (Baki et al., 2004; Kang et al., 2005). This last concept is in contrast to the widely held view that FAD mutations cause a gain of presenilin γ-secretase function thus increasing production of neurotoxic species like Aβ1-42 (see, however, ARF ongoing discussion). The data on Aph-1/aPKC/PAR-1 indicate a new pathway that may also contribute to tau phosphorylation. Clearly, new exciting data emerging in the last two years from several laboratories promote novel concepts not only for the biological functions of PS1, but also for the mechanisms by which presenilin FAD mutations induce the specific neuropathology associated with AD.

View all comments by Nikolaos K. Robakis