Phosphorylation and hsp90 binding mediate heat shock stabilization of p53.
The p53 tumor suppressor is stabilized and activated by diverse stress signals. In this study, we investigated the mechanism of p53 activation by heat shock. We found that heat shock inhibited p53 ubiquitination and caused accumulation of p53 at the post-transcriptional level. Heat shock induced phosphorylation of p53 at serine 15 in an ATM kinase-dependent fashion, which may contribute partially to heat-induced p53 accumulation. However, p53 accumulation also occurred after heat shock in ATM-deficient cells. Heat shock induced conformational change of wild type p53 and binding to hsp90. Inhibition of hsp90-p53 interaction by geldanamycin prevented p53 accumulation partially in ATM-wild type cells and completely in ATM-deficient cells. Therefore, phosphorylation and interaction with hsp90 both contribute to stabilization of p53 after heat shock.
Wang
Chuangui
C
Molecular Oncology Program, H. Lee Moffitt Comprehensive Cancer Center and Research Institute, Tampa, Florida 33612, USA.
Chen
Jiandong
J
D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response; D006801:Humans; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D012694:Serine / Q000737:chemistry / Q000378:metabolism; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000378:metabolism*
D018841:HSP90 Heat-Shock Proteins; D016159:Tumor Suppressor Protein p53; D012694:Serine