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Lipids as modulators of proteolytic activity of BACE: involvement of cholesterol, glycosphingolipids, and anionic phospholipids in vitro.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2005 Nov 04; Vol. 280 (44), pp. 36815-23. Date of Electronic Publication: 2005 Aug 22. - Publication Year :
- 2005
-
Abstract
- The beta-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 beta-amyloid peptide (Abeta). Previous results have suggested that the regulation of beta-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 mum) unilamellar vesicles, and found approximately 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 ( approximately 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).
- Subjects :
- Amyloid Precursor Protein Secretases
Aspartic Acid Endopeptidases
Baculoviridae genetics
Endopeptidases genetics
Humans
In Vitro Techniques
Recombinant Proteins chemistry
Recombinant Proteins genetics
Recombinant Proteins metabolism
Amyloid beta-Peptides metabolism
Cerebrosides metabolism
Cholesterol metabolism
Endopeptidases metabolism
Glycosphingolipids metabolism
Phosphatidylserines metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 280
- Issue :
- 44
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 16115865
- Full Text :
- https://doi.org/10.1074/jbc.M504484200