JunD protects cells from p53-dependent senescence and apoptosis
J B Weitzman1, L Fiette, K Matsuo
1Unite des Virus Oncogenes CNRS URA1644 Pasteur Institute, Paris, France.
Molecular Cell
|December 7, 2000
Summary
JunD protein protects cells from premature aging and stress-induced cell death. Loss of JunD leads to growth arrest in primary cells but increased proliferation in immortalized cells, impacting Ras-p53 signaling.
Area of Science:
- Molecular Biology
- Cell Biology
- Oncology
Background:
- JunD is a widely expressed member of the Jun family and the Activator Protein-1 (AP-1) transcription factor complex.
- The AP-1 complex plays critical roles in cellular processes including proliferation, differentiation, and apoptosis.
Purpose of the Study:
- To investigate the role of JunD in cellular responses to stress, senescence, and oncogenic signaling.
- To elucidate the relationship between JunD, Ras, and p53 pathways.
Main Methods:
- Gene knockout studies in primary fibroblasts and immortalized cell lines.
- Analysis of cell proliferation, senescence markers (p19Arf), apoptosis, and cell cycle regulators (cyclinD1).
- In vivo studies using a mouse model of TNF-alpha-induced hepatitis.
Main Results:
- Primary fibroblasts lacking JunD exhibited p53-dependent growth arrest, premature senescence, and increased apoptosis upon UV irradiation.
- Immortalized cell lines lacking JunD showed increased proliferation and cyclin D1 levels, similar to oncogenic Ras expression.
- JunD deficiency sensitized cells to TNF-alpha cytotoxicity, and JunD demonstrated an anti-apoptotic role in vivo.
Conclusions:
- JunD acts as a crucial modulator of signaling pathways linking Ras to p53.
- JunD protects cells against senescence and apoptosis in response to various stress stimuli.
- These findings highlight JunD's role as a tumor suppressor by preventing aberrant proliferation and promoting cell survival under stress.
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