Presenilins in synaptic function and disease.

The presenilin genes harbor approximately 90% of mutations linked to early-onset familial Alzheimer's disease (FAD), but how these mutations cause the disease is still being debated. Genetic analysis in Drosophila and mice demonstrate that presenilin plays essential roles in synaptic function, learning and memory, as well as neuronal survival in the adult brain, and the FAD-linked mutations alter the normal function of presenilin in these processes. Presenilin has also been reported to regulate the calcium homeostasis of intracellular stores, and presynaptic presenilin controls neurotransmitter release and long-term potentiation through modulation of calcium release from intracellular stores. In this review, we highlight recent advances in deciphering the role of presenilin in synaptic function, calcium regulation and disease, and pose key questions for future studies.