HSF1, also known as Heat shock factor protein 1 (HSF-1) or Heat shock transcription factor 1 (HSTF-1), and encoded by the gene HSF1/HSTF1, is a DNA binding transcription factor that binds heat shock promoter elements (HSE’s) and activates transcription. In higher eukaryotes, HSF1 is unable to bind to HSE regions unless the cells are heat shocked. HSF1 is normally a monomer that interacts with HSP90 and other chaperones in a large complex in the cytoplasm. Upon heat shock HSF1 is released from the complex, dimerizes, and is transported into the nucleus. HSF1 is localized to the cytoplasm during normal growth the protein localizes to the nucleus upon heat shock. HSF1 is part of the cellular stress response, and HSF1 is known to interact with many other stress- induced proteins including NCOA6, SYMPK, RALBP1, HSF2, CEBPB, HSPA1A, Heat shock protein 90kDa alpha and HSPA.
