Regulation of the heat shock response by heat shock transcription factors.

The heat shock response is characterized by a rapid and robust increase in heat shock proteins upon exposure to protein-damaging stresses. This evolutionarily conserved cellular protection mechanism is primarily regulated at the level of transcription. In bacteria, heat shock-induced transcription is regulated by the activation of σ32 factor, whereas eukaryotes utilize heat shock transcription factors (HSFs) that bind to specific heat shock elements (HSEs) within the promoters of their target genes. Unlike yeasts, nematodes, and fruit flies, which have a single HSF, vertebrates and plants have an entire HSF family. In addition to stress-induced activation, some members of the HSF family are also activated under non-stressful conditions, including development and differentiation. The activity of HSFs is under post-translational control, requiring trimerization, DNA binding, and hyperphosphorylation. The interplay between different family members and other interacting proteins adds further complexity to HSF-mediated transcription. Here, we summarize the current knowledge of the transcriptional regulation of the heat shock response, highlighting recent advances in exploring the multi-faceted nature of heat shock transcription. [ABSTRACT FROM AUTHOR]