Disease relevance of HSF1

• The heat shock factor (HSF1) is the central regulator of the heat stress (hs) response and is required for stimulating the transcription of the hs genes and consequently the expression of heat shock proteins [1].
• After expression in Escherichia coli the recombinant Athsf1 protein binds specifically to a synthetic oligonucleotide containing five heat shock elements [2].

High impact information on HSF1

• Among the tested mutants corresponding to 48 heat-induced genes, only the heat shock transcription factor HsfA2 knockout mutant showed an obvious phenotype [3].
• The transcript levels of the HsfA2 target genes, as well as HsfA2 transcripts, were induced by treating with exogenous H(2)O(2) [4].
• In the HsfA2-overexpressing Arabidopsis (Pro(35S):HsfA2) plants, 46 genes, including a large number of heat-shock proteins, ascorbate peroxidase 2 and galactinol synthase 1 and 2, were highly expressed compared with those in the wild-type plants [4].
• Generation of dominant-negative effects on the heat shock response in Arabidopsis thaliana by transgenic expression of a chimaeric HSF1 protein fusion construct [5].
• Heat stress- and heat shock transcription factor-dependent expression and activity of ascorbate peroxidase in Arabidopsis [6].

Biological context of HSF1

• The HSF1 kinase interacts with the cell-cycle control protein Suc1p and is immunoprecipitated by an antibody specific for the Arabidopsis cyclin-dependent CDC2a kinase [7].
• The molecular mechanisms underlying the differences between Hsp18.2 and Hsp70 in the kinetics of HSF1/promoter binding and corresponding mRNA expression profiles are discussed [8].
• Phosphorylation by a cyclin-dependent kinase modulates DNA binding of the Arabidopsis heat-shock transcription factor HSF1 in vitro [7].
• ATHSF1 is a heat shock transcription factor (HSF) of Arabidopsis that is constitutively expressed but its activity for DNA binding, trimer formation and transcriptional activation of heat shock (hs) genes is repressed at normal temperatures [9].
• Particularly striking is the finding of a new class of Hsfs (AtHsfC1) closely related to Hsf1 from rice and to Hsfs identified from frequently found expressed sequence tags of tomato, potato, barley, and soybean [10].

Associations of HSF1 with chemical compounds

• The transcript level of HsfA2 was significantly increased under the several stress conditions or by the H(2)O(2) treatment [4].
• Here we describe partial purification, identification, and characterization of a protein kinase that phosphorylates the Arabidopsis heat-shock factor AtHSF1 at multiple serine residues [7].
• The HSF1 kinase forms a stable complex with AtHSF1, which can be detected by kinase pull-down assays using a histidine-tagged AtHSF1 substrate [7].

Physical interactions of HSF1

• Our results suggest that Arabidopsis HSFs immunoreactive for HSF1 antibodies bind constitutively to the HSP18.2 gene [11].

Other interactions of HSF1

• Subdomain mapping indicates an interaction of the activation domain and DNA-binding domain of HSF1 with HSP70 [12].
• Interaction between the Arabidopsis thaliana heat shock transcription factor HSF1 and the TATA binding protein TBP [1].
• Complete and selective loss of the promoter binding activities of AtHSF1 or AtHSF3, verified by immunoprecipitation assays, had no obvious effects on the heat shock (HS) response in the individual mutant lines [13].

Analytical, diagnostic and therapeutic context of HSF1

• Here the interaction between HSF and HSP70 is reported using electrophoretic mobility shift and yeast two-hybrid assays [12].
• Using UV laser cross-linking and immunoprecipitation we measured the in vivo binding of Arabidopsis heat shock transcription factor HSF1 to the promoters of target genes, Hsp18.2 and Hsp70 [8].

References