Fig. 1: Identification of the co-activator TRRAP that interacts with HSF1.

a Relative enrichment of proteins identified in HSF1 ChIP preparations from heat-shocked cells. HeLa cells were untreated or treated with heat shock at 42 °C for 60 min, and HSF1-interacting proteins were identified by ChIP-MS. Thirty-one proteins highly enriched upon HS (difference of peptide numbers >3) are shown. Proteins related to histone modifications are indicated in red. b HSF1 interacts with TRRAP in the nucleus during heat shock. Cytoplasmic (Cyto) and nuclear (Nucl) extracts were prepared and complexes co-immunoprecipitated using anti-IgG or anti-HSF1 and subjected to immunoblotting. c Expression of HSP72 mRNA in TRRAP-KD cells during heat shock. Levels of HSP72 mRNA were quantified, and the levels relative to that in control SCR-treated cells are shown. Extracts of cells were subjected to immunoblotting. d Venn diagram of HSF1 and TRRAP ChIP-seq binding peaks in HeLa cells untreated (Cont.) or treated with heat shock (HS). Because the TRRAP antibody generates a low signal-to-noise ratio in ChIP assay, the limited numbers of TRRAP binding peaks were identified using ChIP-seq. e MA (log ratio versus abundance) plot of ChIP-seq binding intensities for HSF1 and TRRAP in control (R₁) and heat shocked (R₂) cells at the common binding peaks for HSF1-HS/TRRAP-HS (28 peaks). The number of reads in the peak regions after normalization for a given sample was counted and the M and A values of each peak were calculated and plotted, where M = log₂(R₂/R₁) and A = log₂(R₁ + R₂)/2. Dots with ratios (M) that increased during heat shock (−log₁₀P > 1) are indicated in red. f ChIP-seq binding profiles of HSF1 and TRRAP in control (Cont.) and heat-shocked (HS) cells. Normalized read numbers are shown and peaks are indicated in red. Norminal p-values were determined by by two-way ANOVA in c. Error bars indicate SEM (n = 3) in c. Experiments were repeated two times for b.