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- Title
An N-terminal p14<sup>ARF</sup> peptide blocks Mdm2-dependent ubiquitination in vitro and can activate p53 in vivo.
- Authors
Midgley, Carol A; Desterro, Joana MP; Saville, Mark K; Howard, Stephanie; Sparks, Alison; Hay, Ronald T; Lane, David P
- Abstract
The p53 tumour suppressor protein is down-regulated by the action of Mdm2, which targets p53 for rapid degradation by the ubiquitin-proteasome pathway. The p14ARF protein is also a potent tumour suppressor that acts by binding to Mdm2 and blocking Mdm2-dependent p53 degradation and transcriptional silencing. We have screened a series of overlapping synthetic peptides derived from the p14ARF protein sequence and found that a peptide corresponding to the first 20 amino acids of ARF (Peptide 3) could bind human Mdm2. The binding site for Peptide 3 on Mdm2 was determined by deletion mapping and lies adjacent to the binding site of the anti-Mdm2 antibody 2A10, which on microinjection into cells can activate p53-dependent transactivation of a reporter plasmid. To determine whether Peptide 3 could similarly activate p53, we expressed a fusion of green fluorescent protein and Peptide 3 in MCF7 and U-2 OS cells and were able to demonstrate induction of p53 protein and p53-dependent transcription. Peptide 3 was able to block in vitro ubiquitination of p53 mediated by Mdm2. Small peptides which are sufficient to block degradation of p53 could provide therapeutic agents able to restore p53-dependent cell death pathways in tumours that retain wild-type p53 expression. Oncogene (2000) 19, 2312–2323
- Subjects
PEPTIDES; UBIQUITIN; P53 antioncogene
- Publication
Oncogene, 2000, Vol 19, Issue 19, p2312
- ISSN
0950-9232
- Publication type
Article
- DOI
10.1038/sj.onc.1203593