Open AccessBach1‐mediated suppression of p53 is inhibited by p19 ARF independently of MDM 2
Author(s) -
Nishizawa Hironari,
Ota Kazushige,
Dohi Yoshihiro,
Ikura Tsuyoshi,
Igarashi Kazuhiko
Publication year - 2012
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2012.02244.x
Subject(s) - gene knockdown , chemistry , immunoprecipitation , microbiology and biotechnology , senescence , transcription factor , cancer research , biology , biochemistry , apoptosis , gene
Cellular senescence prevents the aberrant proliferation of damaged cells. The transcription factor Bach1 binds to p53 to repress cellular senescence, but it is still unclear how the Bach1–p53 interaction is regulated. We found that the Bach1–p53 interaction was inhibited by oncogenic Ras, bleomycin, and hydrogen peroxide. Proteomics analysis of Bach1 complex revealed its interaction with p19 ARF , a tumor suppressor that competitively inhibited the Bach1–p53 interaction when overexpressed within cells. Reduction of MDM 2 expression in wild‐type murine embryonic fibroblasts ( MEF s) did not result in slower proliferation, showing that Bach1 plays a role in keeping the proliferation of MEF s independent of MDM 2. Consistent with this interpretation, expression of p21 was highly induced in MEF s when both Bach1 and MDM 2 were abrogated. The level of Bach1 protein was reduced on knockdown of p53. These results suggest that p53 activation involves its dissociation from Bach1, achieved in part by the competitive binding of p19 ARF to Bach1. The p19 ARF –Bach1 interaction constitutes a regulatory pathway of p53 in parallel with the p19 ARF – MDM 2 pathway. ( Cancer Sci 2012; 103: 897–903)