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Updated: Jun 16, 2026
10:08
Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain
Published on: August 28, 2012
Evidence for dimeric BACE-mediated APP processing
Shaobo Jin1, Karin Agerman, Karin Kolmodin
1Department of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden.
Biochemical and Biophysical Research Communications
|January 26, 2010
Summary
Mutating active site aspartic acids in beta-secretase (BACE) inactivated the enzyme. Co-expression of single mutants restored BACE activity, suggesting dimer formation for amyloid precursor protein processing.
Area of Science:
- Biochemistry
- Neuroscience
- Molecular Biology
Background:
- Beta-secretase (BACE) is a key enzyme in amyloid precursor protein (APP) processing.
- BACE is a significant pharmacological target for Alzheimer's disease due to its role in amyloid-beta production.
Purpose of the Study:
- To investigate the enzymatic function of BACE by mutating its active site residues.
- To explore the potential for complementation between BACE active site mutants.
Main Methods:
- Site-directed mutagenesis of aspartic acid residues in the BACE active site.
- Assessment of BACE enzymatic activity, glycosylation, and subcellular localization.
- Analysis of APP processing and inhibition by a small molecule BACE inhibitor.
Main Results:
- Single active site BACE mutants were functionally inactive but retained normal localization and glycosylation.
- Substitution of both active site aspartic acids resulted in ER-retained, partially glycosylated, inactive BACE.
- Co-expression of single mutants partially restored APP beta-site cleavage, indicating functional complementation.
Conclusions:
- BACE active site mutants can form partially functional dimers, restoring APP processing.
- This complementation suggests a dimeric structure for BACE's enzymatic activity.
- The restored activity is sensitive to BACE-specific inhibitors, validating the therapeutic target.
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