Binds DNA and represses gene expression. Plays a role in regulation of life span, possibly by regulating transcription of genes important for lipid metabolism. Homodimer. The THAP-type zinc finger mediates DNA-binding but is not required for repression of gene expression. Adult life span extension and increased resistance to oxidative and heat stress but not to DNA damage, starvation or pathogen stress. Belongs to the D-isomer specific 2-hydroxyacid dehydrogenase family. In contrast to other members of the family, lacks the conserved Arg and Glu active sites at positions 417 and 446 respectively, suggesting that it lacks dehydrogenase activity.