Relevant functional domains are highlighted; they are the N-terminal activation domain (NAD), the DNA-binding domain (DBD), the trimerization domain (TRM), and the C-terminal activation domain (CAD). The HSFΔNAD construct was made by deleting the first 65 residues of the protein, highlighted by the gray box. The HSFΔCAD construct was made by deleting the last 250 residues, highlighted by the black box.