Abstract
Presenilin (PS) proteins control the proteolytic cleavage that precedes nuclear access of the Notch intracellular domain. Here we observe that a partial activation of the HES1 promoter can be detected in PS1/PS2 (PS1/2) double null cells using Notch1ΔE constructs or following Delta1 stimulation, despite an apparent abolition of the production and nuclear accumulation of the Notch intracellular domain. PS1/2-independent Notch activation is sensitive to Numblike, a physiological inhibitor of Notch. PS1/2-independent Notch signaling is also inhibited by an active γ-secretase inhibitor in the low micromolar range and is not inhibited by an inactive analogue, similar to PS-dependent Notch signaling. However, experiments using a Notch1-Gal4-VP16 fusion protein indicate that the PS1/2-independent activity does not release Gal4-VP16 and is therefore unlikely to proceed via an intramembranous cleavage. These data reveal that a novel PS1/2-independent mechanism plays a partial role in Notch signal transduction.
Original language | English (US) |
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Pages (from-to) | 8154-8165 |
Number of pages | 12 |
Journal | Journal of Biological Chemistry |
Volume | 277 |
Issue number | 10 |
DOIs | |
State | Published - Mar 8 2002 |
ASJC Scopus subject areas
- Molecular Biology
- Biochemistry
- Cell Biology