Illustration of the DNA-dependent protein kinase (DNA-PK) complex VIII. This enzyme regulates repair of double strand breaks in DNA (deoxyribonucleic acid) strands through a mechanism known as non-homologous end joining (NHEJ). It also plays a role in the maintenance of telomeres (protective areas at the ends of chromosomes) and in triggering programmed cell death (apoptosis) in cells with severe DNA damage.