Human THAP4 is a 577 residue protein of unknown function that is proposed to bind DNA in a sequence specific manner similar to THAP1 and has been found to be upregulated in response to heat shock.THAP4 is expressed in a relatively uniform manner in a broad range of tissues and appears to be upregulated in lymphoma cells and highly expressed in heart cells13. The C-terminal domain of THAP4 (residues 415-577), designated here as cTHAP4, is evolutionarily conserved and is observed in all know THAP4 orthologues. Several single domain proteins lacking a THAP domain are found in plants and bacteria, and show significant levels of homology to cTHAP4. It appears that cTHAP4 belongs to a large class of proteins that have yet to be fully functionally characterized.