Lipids as modulators of proteolytic activity of BACE: Involvement of cholesterol, glycosphingolipids, and anionic phospholipids in vitro
Publikation: Beitrag in Fachzeitschrift › Forschungsartikel › Beigetragen › Begutachtung
Beitragende
Abstract
The β-secretase, BACE, is a membrane spanning aspartic protease, which cleaves the amyloid precursor protein (APP) in the first step of proteolytic processing leading to the formation of the neurotoxic β-amyloid peptide (Aβ). Previous results have suggested that the regulation of β-secretase and BACE access to APP is lipid dependent, and involves lipid rafts. Using the baculovirus expression system, we have expressed recombinant human full-length BACE in insect cells and purified milligram amounts to homogeneity. We have studied partitioning of fluorophor-conjugated BACE between the liquid ordered and disordered phases in giant (10-150 μm) unilamellar vesicles, and found -20% to associate with the raft-like, liquid-ordered phase; the fraction associated with liquid-ordered phase increased upon cross-linking of raft lipids. To examine involvement of individual lipid species in modulating BACE activity, we have reconstituted the purified BACE in large (-100 nm) unilamellar vesicles, and determined its specific activity in vesicles of various lipid compositions. We have identified 3 groups of lipids that stimulate proteolytic activity of BACE: 1) neutral glycosphingolipids (cerebrosides), 2) anionic glycerophospholipids, and 3) sterols (cholesterol).
Details
Originalsprache | Englisch |
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Seiten (von - bis) | 36815-36823 |
Seitenumfang | 9 |
Fachzeitschrift | Journal of Biological Chemistry |
Jahrgang | 280 |
Ausgabenummer | 44 |
Publikationsstatus | Veröffentlicht - 4 Nov. 2005 |
Peer-Review-Status | Ja |
Externe IDs
PubMed | 16115865 |
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