Abstract
The E2F1 transcription factor is a critical downstream target of the tumor suppressor RB. When activated, E2F1 induces cell proliferation. In addition, E2F1 can induce apoptosis via both p53-dependent and p53-independent pathways. A number of E2F-regulated genes, including ARF, ATM and Chk2, contribute to E2F-induced p53 stabilization. However, it is not known how E2F directs p53 activity towards apoptosis rather than growth arrest. We show that E2F1 upregulates the expression of four proapoptotic cofactors of p53 - ASPP1, ASPP2, JMY and TP53INP1 - through a direct transcriptional mechanism. Adenovirus E1A protein also induces upregulation of these genes, implicating endogenous E2F in this effect. TP53INP1 was shown to mediate phosphorylation of p53 on serine 46. We demonstrate that activation of E2F1 leads to phosphorylation of p53 on serine 46 and this modification is important for E2F1-p53 cooperation in apoptosis. Overall, these data provide novel functional links between RB/E2F pathway and p53-induced apoptosis.
| Original language | English |
|---|---|
| Pages (from-to) | 377-383 |
| Number of pages | 7 |
| Journal | Cell Death and Differentiation |
| Volume | 12 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2005 |
| Externally published | Yes |
Bibliographical note
Funding Information:We are grateful to Yocheved Lamed for excellent technical assistance. We thank Karen Vousden and Xin Lu for communicating results prior to publication. We also thank Xin Lu for antibodies to ASPP1 and ASPP2 and Yoichi Taya for the pC53-SNS-S46A plasmid. This work was supported by an Israel Science Foundation (ISF) grant to DG, and by grant R37 CA40099 from the National Cancer Institute to MO. MC was supported by a Pasteur-Weizmann post-doctoral fellowship.
Keywords
- ASPP family
- Apoptosis
- E2F
- JMY
- TP53INP1
- p53