Transcriptional coregulator that functions together with transcription factor HSF1. Interacts with transcription factor HSF1 on chromatin. Induced by high temperature. Sensitive to high temperature (PubMed:27866167). Normal cellular melanin level (PubMed:25972480). Increases SSA2 mRNA level (PubMed:27866167). Mildly decreases virulence in a mouse intratracheal infection model (PubMed:25972480). Belongs to the heat shock protein 70 family.