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In vivo reconstitution of gamma-secretase in Drosophila results in substrate specificity

Item Type:Article
Title:In vivo reconstitution of gamma-secretase in Drosophila results in substrate specificity
Creators Name:Stempfle, D. and Kanwar, R. and Loewer, A. and Fortini, M.E. and Merdes, G.
Abstract:The intramembrane aspartyl protease gamma-secretase plays a fundamental role in several signaling pathways involved in cellular differentiation and has been linked with a variety of human diseases, including Alzheimer's disease. Here, we describe a transgenic Drosophila model for in vivo-reconstituted gamma-secretase, based on expression of epitope-tagged versions of the four core gamma-secretase components, Presenilin, Nicastrin, Aph-1, and Pen-2. In agreement with previous cell culture and yeast studies, coexpression of these four components promotes the efficient assembly of mature, proteolytically active gamma-secretase. We demonstrate that in vivo-reconstituted gamma-secretase has biochemical properties and a subcellular distribution resembling those of endogenous gamma-secretase. However, analysis of the cleavage of alternative substrates in transgenic-fly assays revealed unexpected functional differences in the activity of reconstituted gamma-secretase toward different substrates, including markedly reduced cleavage of some APP family members compared to cleavage of the Notch receptor. These findings indicate that in vivo under physiological conditions, additional factors differentially modulate the activity of gamma-secretase toward its substrates. Thus, our approach for the first time demonstrates the overall functionality of reconstituted gamma-secretase in a multicellular organism and the requirement for substrate-specific factors for efficient in vivo cleavage of certain substrates.
Keywords:Amyloid Precursor Protein Secretases, Drosophila Proteins, Genetically Modified Animals, Membrane Glycoproteins, Membrane Proteins, Phenotype, Presenilins, Signal Transduction, Substrate Specificity, Animals, Drosophila Melanogaster
Source:Molecular and Cellular Biology
Publisher:American Society for Microbiology
Page Range:3165-3175
Date:July 2010
Official Publication:https://doi.org/10.1128/MCB.00030-10
PubMed:View item in PubMed

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