Intramembrane Proteases--Mixing Oil and Water

Abstract
The report that the newly characterized signal peptide peptidase is an aspartic protease that resembles presenilin ( Weihofen et al.) has generated excitement among Alzheimer's disease (AD) researchers. As Wolfe and Selkoe explain in their Perspective, the new work supplements existing evidence that presenilin (which is mutated in a rare familial form of AD) is an aspartic protease responsible for the intramembranous cleavage of many substrates, including the amyloid precursor protein.