Ku80 Single-stranded DNA-dependent ATP-dependent helicase. 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 XRCC6. Involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair and V(D)J recombination. The XRCC5/6 dimer acts as regulatory subunit of the DNA-dependent protein kinase complex DNA-PK by increasing the affinity of the catalytic subunit PRKDC to DNA by 100-fold. The XRCC5/6 dimer is probably involved in stabilizing broken DNA ends and bringing them together. The assembly of the DNA-PK complex to DNA ends is required for the NHEJ ligation step. In association with NAA15, the XRCC5/6 dimer binds to the osteocalcin promoter and activates osteocalcin expression. The XRCC5/6 dimer probably also acts as a 5'-deoxyribose-5-phosphate lyase (5'-dRP lyase), by catalyzing the beta-elimination of the 5' deoxyribose-5-phosphate at an abasic site near double-strand breaks. XRCC5 probably acts as the catalytic subunit of 5'-dRP activity, and allows to 'clean' the termini of abasic sites, a class of nucleotide damage commonly associated with strand breaks, before such broken ends can be joined. The XRCC5/6 dimer together with APEX1 acts as a negative regulator of transcription. Plays a role in the regulation of DNA virus-mediated innate immune response by assembling into the HDP-RNP complex, a complex that serves as a platform for IRF3 phosphorylation and subsequent innate immune response activation through the cGAS-STING pathway. Belongs to the ku80 family. Note: This description may include information from UniProtKB.

Protein type: DNA-binding; EC 3.6.1.-; EC 3.6.4.-; Helicase; Nuclear receptor co-regulator; Nucleolus; RNA-binding

Chromosomal Location of human Ortholog: 2q35

Cellular Component: chromosome, telomeric region; cytosol; DNA-dependent protein kinase complex; extracellular region; Ku70:Ku80 complex; nonhomologous end joining complex; nuclear telomere cap complex; nucleolus; nucleoplasm; nucleus; plasma membrane; protein-containing complex; protein-DNA complex; ribonucleoprotein complex; secretory granule lumen; site of DNA damage; small-subunit processome

Molecular Function: 5'-deoxyribose-5-phosphate lyase activity; ATP binding; ATP hydrolysis activity; ATP-dependent activity, acting on DNA; damaged DNA binding; DNA binding; DNA end binding; DNA helicase activity; double-stranded DNA binding; double-stranded telomeric DNA binding; enzyme activator activity; protein binding; protein-containing complex binding; RNA binding; telomeric DNA binding; transcription cis-regulatory region binding; U3 snoRNA binding; ubiquitin protein ligase binding

Biological Process: activation of innate immune response; cellular hyperosmotic salinity response; cellular response to fatty acid; cellular response to gamma radiation; cellular response to leukemia inhibitory factor; cellular response to X-ray; DNA damage response; DNA duplex unwinding; DNA recombination; double-strand break repair; double-strand break repair via nonhomologous end joining; hematopoietic stem cell differentiation; hematopoietic stem cell proliferation; innate immune response; negative regulation of DNA-templated transcription; negative regulation of t-circle formation; neurogenesis; positive regulation of catalytic activity; positive regulation of neurogenesis; positive regulation of protein kinase activity; positive regulation of telomerase activity; positive regulation of telomere maintenance via telomerase; protein localization to chromosome, telomeric region; recombinational repair; regulation of smooth muscle cell proliferation; regulation of telomere maintenance; response to xenobiotic stimulus; small-subunit processome assembly; telomere maintenance

Reference #: P13010 (UniProtKB)

Alt. Names/Synonyms: 86 kDa subunit of Ku antigen; ATP-dependent DNA helicase 2 subunit 2; ATP-dependent DNA helicase II 80 kDa subunit; CTC box-binding factor 85 kDa subunit; CTC85; CTCBF; DNA repair protein XRCC5; FLJ39089; G22P2; KARP-1; KARP1; Ku autoantigen, 80kD); Ku autoantigen, 80kDa; Ku80; Ku86; Ku86 autoantigen related protein 1; KUB2; Lupus Ku autoantigen protein p86; NFIV; Nuclear factor IV; Thyroid-lupus autoantigen; TLAA; X-ray repair complementing defective repair in Chinese hamster cells 5 (double-strand-break rejoining; X-ray repair complementing defective repair in Chinese hamster cells 5 (double-strand-break rejoining); X-ray repair cross complementing 5; X-ray repair cross-complementing protein 5; X-ray repair, complementing defective, repair in Chinese hamster; XRCC5

Gene Symbols: XRCC5

Molecular weight: 82,705 Da

Basal Isoelectric point: 5.55 Predict pI for various phosphorylation states

Protein-Specific Antibodies, siRNAs or Recombinant Proteins from Cell Signaling Technology^®

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Ku80

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