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Original Article |
Correspondence to: Eui-Ju Choi, National Creative Research Initiative Center for Cell Death, Graduate School of Biotechnology, Korea University, Seoul, 136-701, Korea. Tel:82-2-3290-3446 Fax:82-2-927-9028 E-mail:ejchoi{at}mail.korea.ac.kr.
Presenilin 1 (PS1) plays a pivotal role in Notch signaling and the intracellular metabolism of the amyloid ß-protein. To understand intracellular signaling events downstream of PS1, we investigated in this study the action of PS1 on mitogen-activated protein kinase pathways. Overexpressed PS1 suppressed the stress-induced stimulation of stress-activated protein kinase (SAPK)/c-Jun NH2-terminal kinase (JNK) in human embryonic kidney 293 cells. Interestingly, two functionally inactive PS1 mutants, PS1(D257A) and PS1(D385A), failed to inhibit UV-stimulated SAPK/JNK. Furthermore, H2O2- or UV-stimulated SAPK activity was higher in mouse embryonic fibroblast (MEF) cells from PS1-null mice than in MEF cells from PS+/+ mice. MEFPS1(-/-) cells were more sensitive to the H2O2-induced apoptosis than MEFPS1(+/+) cells. Ectopic expression of PS1 in MEFPS1(-/-) cells suppressed H2O2-stimulated SAPK/JNK activity and apoptotic cell death. Together, our data suggest that PS1 inhibits the stress-activated signaling by suppressing the SAPK/JNK pathway.
Key Words:
apoptosis, c-Jun NH2-terminal kinase, presenilin 1,
-secretase, stress-activated protein kinase
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