Uncoupling Stress-Inducible Phosphorylation of Heat Shock Factor 1 from Its Activation

Marek Budzynski, Mikael Puustinen, Jenny Joutsen, Lea Sistonen

Tutkimustuotos: LehtiartikkeliArtikkeliTieteellinenvertaisarvioitu

40 Sitaatiot (Scopus)
4 Lataukset (Pure)

Abstrakti

In mammals the stress-inducible expression of genes encoding heat shock proteins is under the control of the heat shock transcription factor 1 (HSF1). Activation of HSF1 is a multistep process, involving trimerization, acquisition of DNA-binding and transcriptional activities, which coincide with several posttranslational modifications. Stress-inducible phosphorylation of HSF1, or hyperphosphorylation, which occurs mainly within the regulatory domain (RD), has been proposed as a requirement for HSF-driven transcription and is widely used for assessing HSF1 activation. Nonetheless, the contribution of hyperphosphorylation to the activity of HSF1 remains unknown. In this study, we generated a phosphorylation-deficient HSF1 mutant (HSF1Δ∼PRD), where the 15 known phosphorylation sites within the RD were disrupted. Our results show that the phosphorylation status of the RD does not affect the subcellular localization and DNA-binding activity of HSF1. Surprisingly, under stress conditions, HSF1Δ∼PRD is a potent transactivator of both endogenous targets and a reporter gene, and HSF1Δ∼PRD has a reduced activation threshold. Our results provide the first direct evidence for uncoupling stress-inducible phosphorylation of HSF1 from its activation, and we propose that the phosphorylation signature alone is not an appropriate marker for HSF1 activity.
AlkuperäiskieliEi tiedossa
Sivut2530–2540
JulkaisuMolecular and Cellular Biology
Vuosikerta35
Numero14
DOI - pysyväislinkit
TilaJulkaistu - 2015
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

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