Protein Kinase, DNA Activated, Catalytic Polypeptide (PRKDC)

The PRKDC gene encodes the catalytic subunit of a nuclear DNA-dependent serine/threonine protein kinase (DNA-PK). The second component is the autoimmune antigen Ku, which is encoded by the G22P1 gene on chromosome 22q. On its own, the catalytic subunit of DNA-PK is inactive and relies on the G22P1 component to direct it to the DNA and trigger its kinase activity; PRKDC must be bound to DNA to express its catalytic properties. The PRKDC protein showed similarity to phosphatidylinositol 3-kinase family members involved in cell cycle control, DNA repair, and DNA damage responses, and had no detectable activity towards lipids. Other PI kinase proteins involved in DNA repair include FKBP12 and the ataxia-telangiectasia gene (ATM), in which mutations lead to genomic instability and predisposition to cancer and ataxia.