An exo-cell assay for examining real-time -secretase activity and inhibition

Abstract

Secretase is an aspartyl protease that cleaves multiple substrates that are involved in broad biological processes ranging from stem cell development to neurodegeneration. The investigation of -secretase has been limited by currently available assays that require genetic or biochemical manipulation in the form of substrate transfection or membrane preparation. Here we report an exo-cell assay that is capable of characterizing -secretase activity in any cellular system without limitation. Using a highly active, recombinant substrate this assay can quickly and easily ascertain the status of -secretase activity in cell systems and patient samples. We have applied this method to determine the activity of -secretase in primary cell samples where transfection and/or membrane isolation are not viable options. Importantly, it allows for the detection of real time -secretase activity after inhibitor or drug treatment. The application of this assay to determine the role of -secretase in physiological and pathological conditions will greatly facilitate our characterization of this complex protease and help in the development and evaluation of -secretase-targeted therapies in Alzheimer's disease or a variety of neoplasms. © 2009 Shelton et al; licensee BioMed Central Ltd.