An in vivo assay for the identification of target proteases which cleave membrane-associated substrates

Proteases not only play a fundamental role in numerous physiological proces ses, but are also involved in several human diseases including Alzheimer's disease (AD), A key protease implicated in AD is the so far unidentified ga mma-secretase, which cleaves the membrane-bound beta-amyloid precursor prot ein (beta APP) at the C-terminus of its amyloid domain within the membrane to release the neurotoxic amyloid beta-peptide, In order to allow the isola tion of proteases, which specifically cleave membrane-bound substrates with in or in the vicinity of a transmembrane domain, we developed a reporter ge ne assay in Saccharomyces cerevisiae. This assay may allow the identificati on of genes encoding target proteases that specifically cleave membrane bou nd substrates by transforming expression libraries. (C) 1999 Federation of European Biochemical Societies.