Alzheimer amyloid precursor aspartyl proteinase activity in CHAPSO homogenates of Spodoptera frugiperda cells
| Autor: | Carter, Troy L., Giuseppe Verdile, David Groth, Alexey Bogush, Stefani Thomas, Patrick Shen, Fraser, Paul E., Paul Mathews, Nixon, Ralph A., Ehrlich, Michelle E., Kwok, John B. J., Peter St. George-Hyslop, Peter Schofield, Yueming Li, Austin Yang, Ralph Martins, Sam Gandy |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Scopus-Elsevier Experts@Minnesota Macquarie University Europe PubMed Central |
| ISSN: | 0893-0341 |
| Popis: | Presenilins are polytopic, integral proteins that control intramembranous proteolysis at the "gamma-" and "epsilon-" cleavage sites of the Alzheimer amyloid-beta precursor protein (APP) to yield amyloid-beta peptide (Abeta) and the APP intracellular domain (AICD). We have overexpressed a constitutively active, pathogenic form of PS1 (known as PS1 Delta exon 9) together with its substrate, APP-C99, in Spodoptera frugiperda (Sf9) cells. Sf9 cells have been reported to lack endogenous gamma-secretase, an unexpected finding since there exists an insect homologue of PS1. In our hands, neither intact insect cells coexpressing PS1 Delta exon 9/APP-C99 nor the aqueous homogenates of these cells displayed obvious products of the gamma- or epsilon-secretase reactions, as reported. Surprisingly, when APP-C99-expressing cells were homogenized in 3[(3-cholamidopropyl) dimethylammonio]-2-hydroxypropanesulfonic acid (CHAPSO), a detergent known to support gamma-secretase activity, subsequent incubation led to the accumulation of an AICD-like peptide (AICD-L). Aspartyl proteinase inhibitors were effective in preventing the appearance of AICD-L, but inhibitors of other classes of proteinases were ineffective. Immunoprecipitation-mass spectrometry of AICD-L revealed its identity as the minor of the two known AICDs. |
| Databáze: | OpenAIRE |
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