The phorbol ester 12-O-tetradecanoylphorbol 13-acetate enhances the heat-induced stress response

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Holmberg, Leppä, Eriksson, Sistonen
Publication year: 1997
Journal: Journal of Biological Chemistry
Journal acronym: J Biol Chem
Volume number: 272
Issue number: 10
Start page: 6792
End page: 6798
ISSN: 0021-9258
eISSN: 1083-351X


Induction of heat shock gene expression is mediated by specific heat shock transcription factors (HSFs), but the signaling pathways leading to activation of HSFs are poorly understood. To elucidate whether protein kinase C-responsive signaling pathways could be involved in the regulation of heat shock gene expression, we have examined the effects of the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA) on the heat-induced stress response in K562 cells. We demonstrate that TPA treatment markedly enhances heat shock gene expression during heat stress, although TPA alone does not induce the heat shock response. This TPA-mediated enhancement can initially be detected as an accelerated acquisition of DNA binding and transcriptional activity of HSF1 resulting in elevated Hsp70 protein concentrations. In the presence of TPA, the attenuation of HSF1 DNA binding activity during continuous exposure to heat shock occurs more rapidly and in concert with the appearance of newly synthesized Hsp70, which supports earlier studies on the autoregulatory role of Hsp70 in deactivation of HSF1. During heat stress, a correlation between the hyperphosphorylation of HSF1 and its transcriptional activity was observed, in both the presence and the absence of TPA. Our results show that the heat-induced stress response can be significantly modulated by activation of protein kinase C-responsive signaling pathways.

Last updated on 2020-28-09 at 03:00