Related Experiment Videos
Partial purification and characterization of gamma-secretase from post-mortem human brain
Mark R Farmery1, Lars O Tjernberg, Sharon E Pursglove
1Karolinska Institutet and Sumitomo Pharmaceuticals Alzheimer Center, Neurotec, Novum, Huddinge, SE-141 57 Sweden. mark.farmery@neurotec.ki.se
The Journal of Biological Chemistry
|April 17, 2003
Summary
Researchers identified gamma-secretase in human brain tissue, crucial for amyloid beta-peptide production in Alzheimer's disease. This finding aids in understanding beta-APP processing and developing new therapeutic targets.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Alzheimer's disease is characterized by amyloid plaque deposition in the brain.
- Amyloid beta-peptide (Abeta) is produced from beta-amyloid precursor protein (beta-APP) via gamma-secretase activity.
- Gamma-secretase is a multimeric complex, but its precise nature in the human brain remains unclear.
Purpose of the Study:
- To investigate the biochemical and molecular characteristics of gamma-secretase in human brain tissue.
- To develop a novel in vitro assay for measuring gamma-secretase activity in human brain.
Main Methods:
- Developed an in vitro gamma-secretase activity assay using detergent-solubilized human brain membranes and a beta-APP-derived fluorescent probe.
- Co-purified gamma-secretase activity with a high molecular weight protein complex.
Main Results:
- Human brain-derived gamma-secretase activity co-purified with presenilin, nicastrin, Aph-1, and Pen-2.
- The enzyme's inhibitor profile and solubility matched findings from cell studies.
- Proteolysis occurred at the Abeta40- and Abeta42-generating cleavage sites.
Conclusions:
- Successfully isolated and characterized gamma-secretase activity from post-mortem human brain.
- This work provides a foundation for identifying brain-specific modulators of beta-APP processing.
- Offers new insights into the role of gamma-secretase in Alzheimer's disease pathogenesis.