Nuclear signaling: a common function of presenilin substrates?

Major progress has recently been made in the characterization of the secretases involved in endoproteolytic processing of the Alzheimer's disease (AD)-associated beta-amyloid precursor protein, betaAPP. betaAPP is the precursor of the amyloid beta-peptide, which is a major constituent of amyloid plaques in the brains of Alzheimer patients. It is now commonly believed that Abeta plays a pivotal role in the pathogenesis of AD, and that inhibiting the production of Abeta may help to treat or to prevent the disease. With beta-secretase and the presenilins, two essential factors in the proteolytic generation of Abeta have now been identified. However, very little is still known about the biological function of the long-known betaAPP. In this review we will discuss a novel putative function of betaAPP in nuclear signaling, an activity, that betaAPP may share with other presenilin substrates such as Notch.