Untersuchungen zur intrazellulären Lokalisation der γ-Sekretase

Schmitt, Stephanie (2011): Untersuchungen zur intrazellulären Lokalisation der γ-Sekretase. Dissertation, LMU München: Faculty of Medicine

Abstract

Alzheimer´s disease is characterized by brain deposition of extracellular amyloid β-peptide containing plaques. The cellular site of γ-secretase activity, which releases amyloid β-peptide and the corresponding APP intracellular domain (AICD) remains controversial. Proposed cleavage sites range from the endoplasmic reticulum, the Golgi apparatus, the cell surface to endosomal compartments. We now used C99-GFP, a fluorescent reporter substrate for γ-secretase activity and monitored AICD production in living cells. C99-GFP is efficiently cleaved by γ-secretase and AICD-GFP is released into the cytosol. Inhibiting γ-secretase results in accumulation of C99-GFP in early endosomes. By blocking selective transport steps along the secretory pathway we demonstrate that γ-secretase does not cleave its substrates in the endoplasmic reticulum, the Golgi/trans-Golgi network or in secretory vesicles. In contrast, inhibition of endocytosis did not inhibit cleavage of C99-GFP. Similar results were obtained for another γ-secretase substrate, NotchΔE. Our results suggest that intracellular domains are generated by γ-secretase at the plasma membrane and/or early endosomes.

• Item Type: Theses (Dissertation, LMU Munich)
• Keywords: Alzheimer’s disease, Amyloid precursor protein, AICD, C99, GFP, γ-Secretase
• Subjects: 600 Technology, Medicine; 600 Technology, Medicine > 610 Medical sciences and medicine
• Faculties: Faculty of Medicine
• Language: German
• Date of oral examination: 24. March 2011
• 1. Referee: Haass, Christian
• Signature of the printed copy: 0700/UMD 14417