Timothy Locksmith sandbox Heat Sock Factor

Introduction

Heat Shock Factor (HSF) is primarily used for the transcription of Heat shock proteins, which are used for the survival of a cell under high temperature stress situations.^[1] Its structure is highly conserved through species from flies to humans, and even all the way to yeast, which suggests that its existence is very important for the survival of organisms. Studies delving into the uses of HSF have proven promising in Cancer research fields. In some instances when cancer cells had their HSF inhibited underwent cell death instead of proliferation, thus ceasing the spread of the cancer and reducing its size. It is hypothesized that HSF is an integral part of cancer cell survival.

Regulation

HSF is inhibited by heat shock proteins under normal conditions (regarding temperature). The main regulator of HSF is the temperature of the surrounding environment. When the temperature is high, Hsp’s then associate elsewhere the in the cell with damages structures, and are therefore less likely to bind to HSF. This allows HSP to move to the inside of the nucleus, and interact with it to produce more Hsp’s. Once enough Hsp’s are created, the damage has been taken care of and the temperature has returned to normal, they can once again bind to HSF, and inhibit it from interacting with the DNA.

Sturcture/DNA Interaction

HSF remains as a monomer when bound with Hsp under non-stressed conditions. Under stressed conditions (increased temperature) three individual monomers of HSF move into the cell’s nucleus, (could only isloate a dimer structure), and then bind to the large Groove of the DNA to Heat shock elements throughout the genome.^[2] Specifically an from each of the monomer bind to "" sections of the genome.^[3] These residues interact with the nucleotide bases, while nearby residues interact with the back bone to stabilize the transcription factor in place. The structure is classified as a "winged" helix turn helix

References

1. ↑ PMCID: 24800749
2. ↑ doi: https://dx.doi.org/10.1126/science.8421783
3. ↑ Littlefield O, Nelson HC. A new use for the 'wing' of the 'winged' helix-turn-helix motif in the HSF-DNA cocrystal. Nat Struct Biol. 1999 May;6(5):464-70. PMID:10331875 doi:10.1038/8269