TY - JOUR
T1 - Hsf1 is required for the nuclear translocation of p53 tumor suppressor
AU - Li, Qiang
AU - Feldman, Rebecca A.
AU - Radhakrishnan, Vijayababu M.
AU - Carey, Steven
AU - Martinez, Jesse D.
N1 - Funding Information:
Address all correspondence to: Jesse D. Martinez, Department of Cell Biology and Anatomy, University of Arizona, Tucson, AZ 85724. E-mail: [email protected] 1This work was supported by National Institutes of Health Grant CA090776. Received 28 March 2008; Revised 16 July 2008; Accepted 18 July 2008 Copyright © 2008 Neoplasia Press, Inc. All rights reserved 1522-8002/08/$25.00 DOI 10.1593/neo.08430
PY - 2008/10
Y1 - 2008/10
N2 - Although the p53 tumor suppressor is most frequently inactivated by genetic mutations, exclusion from the nucleus is also seen in human tumors. We have begun to examine p53 nuclear importation by isolating a series of mutant cells in which the temperature-sensitive murine p53Val135 mutant is sequestered in the cytoplasm. We previously showed that that three of them (ALTR12, ALTR19, and ALTR25) constituted a single complementation group. Here, we found that ALTR12 cells are more sensitive to heat stress than either ALTR19 or ALTR25 and that there was a complete lack of induction of Hsp70 in response to heat shock. Western blot analysis showed no expression of the Hsf1 transcription factor, and neither heat shock nor azetidine could induce p53 nuclear localization in ALTR12 cells but did in parental A1-5 cells. Suppression of Hsf1 in A1-5 cells with quercetin or an Hsf1 siRNA reduced p53 nuclear importation and inhibited p53-mediated activation of a p21 reporter. Most convincingly, p53 nuclear importation could be restored in ALTR12 cells by introducing an exogenous Hsf1 gene. Collectively, our result suggests that Hsf1 is required for p53 nuclear importation and activation and implies that heat shock factors play a role in the regulation of p53.
AB - Although the p53 tumor suppressor is most frequently inactivated by genetic mutations, exclusion from the nucleus is also seen in human tumors. We have begun to examine p53 nuclear importation by isolating a series of mutant cells in which the temperature-sensitive murine p53Val135 mutant is sequestered in the cytoplasm. We previously showed that that three of them (ALTR12, ALTR19, and ALTR25) constituted a single complementation group. Here, we found that ALTR12 cells are more sensitive to heat stress than either ALTR19 or ALTR25 and that there was a complete lack of induction of Hsp70 in response to heat shock. Western blot analysis showed no expression of the Hsf1 transcription factor, and neither heat shock nor azetidine could induce p53 nuclear localization in ALTR12 cells but did in parental A1-5 cells. Suppression of Hsf1 in A1-5 cells with quercetin or an Hsf1 siRNA reduced p53 nuclear importation and inhibited p53-mediated activation of a p21 reporter. Most convincingly, p53 nuclear importation could be restored in ALTR12 cells by introducing an exogenous Hsf1 gene. Collectively, our result suggests that Hsf1 is required for p53 nuclear importation and activation and implies that heat shock factors play a role in the regulation of p53.
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U2 - 10.1593/neo.08430
DO - 10.1593/neo.08430
M3 - Article
C2 - 18813348
AN - SCOPUS:54249085828
SN - 1522-8002
VL - 10
SP - 1138
EP - 1145
JO - Neoplasia
JF - Neoplasia
IS - 10
ER -