the 80-kilodalton subunit of the Ku complex, also known as ATP-dependant DNA helicase II. A single stranded DNA-dependent ATP-dependent helicase. It functions together with the DNA ligase IV-XRCC4 complex in the repair of DNA double-strand break by non-homologous end joining and the completion of V(D)J recombination events. This gene functionally complements Chinese hamster xrs-6, a mutant defective in DNA double-strand break repair and in ability to undergo V(D)J recombination. A rare microsatellite polymorphism in this gene is associated with cancer in patients of varying radiosensitivity. Has a role in chromosome translocation. The DNA helicase II complex binds preferentially to fork-like ends of double-stranded DNA in a cell cycle-dependent manner. It works in the 3'-5' direction. Binding to DNA may be mediated by p70. Note: This description may include information from UniProtKB.
Molecular Function: 5'-deoxyribose-5-phosphate lyase activity; damaged DNA binding; double-stranded DNA binding; double-stranded telomeric DNA binding; protein binding; protein C-terminus binding; telomeric DNA binding; ubiquitin protein ligase binding
Biological Process: double-strand break repair; double-strand break repair via nonhomologous end joining; negative regulation of transcription, DNA-dependent; positive regulation of interferon type I production; regulation of smooth muscle cell proliferation; telomere maintenance