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Published on: October 17, 2015
Cysteine 73 in bleomycin hydrolase is critical for amyloid precursor protein processing
I M Lefterov1, R P Koldamova, M I Lefterova
1Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
Human bleomycin hydrolase (hBH) regulates amyloid precursor protein (APP) processing. This enzyme
Area of Science:
- Biochemistry
- Neuroscience
- Molecular Biology
Background:
- Alzheimer's disease is characterized by amyloid plaques, primarily composed of amyloid beta (Aβ).
- Soluble amyloid precursor protein (APP) and its Aβ fragment are implicated in Alzheimer's pathogenesis.
- Human bleomycin hydrolase (hBH), a neutral cysteine protease, is investigated for its role in APP processing.
Purpose of the Study:
- To investigate the interaction between human bleomycin hydrolase (hBH) and amyloid precursor protein (APP).
- To determine the role of hBH in the secretion of amyloid beta (Aβ).
Main Methods:
- Yeast two-hybrid assays were employed to identify interactions between hBH and APP.
- In vitro binding studies characterized the specific region of hBH involved in APP interaction.
- Ectopic expression of hBH and a catalytically inactive mutant (C73S) assessed Aβ secretion.
Main Results:
- APP was found to interact with a 68-amino acid region of hBH, including its catalytic domain.
- Ectopic expression of hBH significantly increased Aβ secretion.
- Mutating the catalytic cysteine 73 (C73S) in hBH abolished the increase in Aβ secretion.
- hBH expression did not affect the secretion of apolipoprotein A-I.
Conclusions:
- Human bleomycin hydrolase (hBH) directly interacts with amyloid precursor protein (APP).
- The catalytic activity of hBH, specifically cysteine 73, is essential for mediating APP processing and increasing Aβ secretion.
- hBH represents a potential therapeutic target for modulating Aβ levels in Alzheimer's disease.
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