Catalyzes the phosphorylation of DNA at 5'-hydroxyl termini and can dephosphorylate its 3'-phosphate termini. Plays an important function in DNA repair following ionizing radiation or oxidative damage.
Expressed in many tissues with highest expression in spleen and testis, and lowest expression in small intestine (PubMed:10446192). Expressed in higher amount in pancreas, heart and kidney and at lower levels in brain, lung and liver (PubMed:10446193).
Involvement in disease
Defects in PNKP are the cause of microcephaly seizures and development delay (MCSZ) [MIM:613402]. It is characterized by microcephaly, infantile-onset seizures, severe intellectual disability and delayed motor milestones with absent speech or only achieving a few words. Most patients also have behavioral problems with hyperactivity. Microcephaly is progressive and without neuronal migration or structural abnormalities, consistent with primary microcephaly.
In the N-terminal section; belongs to the DNA 3' phosphatase family.
Phosphorylated upon DNA damage, probably by ATM or ATR.