Quantitative comparison of presenilin protein expression reveals greater activity of PS2-γ-secretase.
FASEB J
; 38(1): e23396, 2024 01.
Article
in En
| MEDLINE
| ID: mdl-38156414
ABSTRACT
γ-secretase processing of amyloid precursor protein (APP) has long been of interest in the pathological progression of Alzheimer's disease (AD) due to its role in the generation of amyloid-ß. The catalytic component of the enzyme is the presenilins of which there are two homologues, Presenilin-1 (PS1) and Presenilin-2 (PS2). The field has focussed on the PS1 form of this enzyme, as it is typically considered the more active at APP processing. However, much of this work has been completed without appropriate consideration of the specific levels of protein expression of PS1 and PS2. We propose that expression is an important factor in PS1- and PS2-γ-secretase activity, and that when this is considered, PS1 does not have greater activity than PS2. We developed and validated tools for quantitative assessment of PS1 and PS2 protein expression levels to enable the direct comparison of PS in exogenous and endogenous expression systems, in HEK-293 PS1 and/or PS2 knockout cells. We show that exogenous expression of Myc-PS1-NTF is 5.5-times higher than Myc-PS2-NTF. Quantitating endogenous PS protein levels, using a novel PS1/2 fusion standard we developed, showed similar results. When the marked difference in PS1 and PS2 protein levels is considered, we show that compared to PS1-γ-secretase, PS2-γ-secretase has equal or more activity on APP and Notch1. This study has implications for understanding the PS1- and PS2-specific contributions to substrate processing, and their potential influence in AD pathogenesis.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Amyloid Precursor Protein Secretases
/
Presenilin-2
/
Alzheimer Disease
Limits:
Humans
Language:
En
Journal:
FASEB J
Journal subject:
BIOLOGIA
/
FISIOLOGIA
Year:
2024
Document type:
Article
Affiliation country:
Australia