The DNA-activated protein kinase (DNA-PK) is a nuclear serine/threonine protein kinase that phosphorylates DNA-binding proteins, including several transcription factors. DNA-PK is one of a very few enzymes known to be regulated through interaction with DNA that does not have DNA as a template or substrate. We suggest that DNA-PK may function in cell homeostasis, in part through the modulation of transcriptional activity.
