Thermotolerance and cell death are distinct cellular responses to stress: dependence on heat shock proteins

A Samali, CI Holmberg, Lea Sistonen, S Orrenius

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    Abstract

    We tested the hypothesis that heat shock protein (Hsp) induction and cell death are mutually exclusive responses to stress. Despite activation of heat shock transcription factor 1 at temperatures ranging from 40 to 46 degrees C, Hsp72 and Hsp27 were not induced above 42 degrees C. Moreover, cells underwent apoptosis at 44 degrees C and necrosis at 46 degrees C, with mitochondrial cytochrome c release at both temperatures. However, only apoptosis was associated with caspase activation. Treatment of cells,vith z-VAD-fmk prior to heat shock at 44 degrees C failed to restore Hsp induction despite inhibition of heat-induced apoptosis. Furthermore, accumulation of Hsps after incubation at 42 degrees C rendered the cells resistant to apoptosis, These results suggest that lack of Hsp induction is the cause rather than the consequence of cell death.
    Original languageUndefined/Unknown
    Pages (from-to)306–310
    Number of pages5
    JournalFEBS Letters
    Volume461
    Issue number3
    DOIs
    Publication statusPublished - 1999
    MoE publication typeA1 Journal article-refereed

    Keywords

    • apoptosis
    • caspase
    • heat shock factor 1
    • heat shock protein
    • necrosis
    • thermotolerance

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