Summary
Application
ICC, IF, IHC-Fr, IHC-P, IP, WB
Basic Information
Immunogen
Synthetic peptide corresponding to the carboxy terminus of human Ku80
Application Notes
The COA includes recommended starting dilutions, optimal dilutions should be determined by the end user.
Formulations & Storage [For reference only, actual COA shall prevail!]
Buffer
1% BSA, 50% glycerol
Purity
> 95% Purity determined by SDS-PAGE.
Storage
Store at +4°C short term (1-2 weeks). Aliquot and store at -20°C long term. Avoid repeated freezethaw cycles.
Target
Full Name
X-Ray Repair Cross Complementing 5
Introduction
The protein encoded by this gene is the 80-kilodalton subunit of the Ku heterodimer protein which is also known as ATP-dependant DNA helicase II or DNA repair protein XRCC5. Ku is the DNA-binding component of the DNA-dependent protein kinase, and 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. [provided by RefSeq, Jul 2008]
Function
Single-stranded DNA-dependent ATP-dependent helicase that plays a key role in DNA non-homologous end joining (NHEJ) by recruiting DNA-PK to DNA (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:11493912).
Required for double-strand break repair and V(D)J recombination (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:11493912).
Also has a role in chromosome translocation (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:11493912).
The DNA helicase II complex binds preferentially to fork-like ends of double-stranded DNA in a cell cycle-dependent manner (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:11493912).
It works in the 3'-5' direction (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:11493912).
During NHEJ, the XRCC5-XRRC6 dimer performs the recognition step: it recognizes and binds to the broken ends of the DNA and protects them from further resection (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:11493912).
Binding to DNA may be mediated by XRCC6 (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:11493912).
The XRCC5-XRRC6 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 (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:20383123, PubMed:11493912).
The XRCC5-XRRC6 dimer is probably involved in stabilizing broken DNA ends and bringing them together (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:20383123).
The assembly of the DNA-PK complex to DNA ends is required for the NHEJ ligation step (PubMed:7957065, PubMed:8621488, PubMed:12145306, PubMed:20383123).
The XRCC5-XRRC6 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 (PubMed:20383123).
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 (PubMed:20383123).
The XRCC5-XRRC6 dimer together with APEX1 acts as a negative regulator of transcription (PubMed:8621488).
In association with NAA15, the XRCC5-XRRC6 dimer binds to the osteocalcin promoter and activates osteocalcin expression (PubMed:12145306).
As part of the DNA-PK complex, involved in the early steps of ribosome assembly by promoting the processing of precursor rRNA into mature 18S rRNA in the small-subunit processome (PubMed:32103174).
Binding to U3 small nucleolar RNA, recruits PRKDC and XRCC5/Ku86 to the small-subunit processome (PubMed:32103174).
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 (PubMed:28712728).
Biological Process
Biological Process activation of innate immune response Source:UniProtKB1 Publication
Biological Process brain development Source:Ensembl
Biological Process cellular hyperosmotic salinity response Source:Ensembl
Biological Process cellular response to DNA damage stimulus Source:UniProtKB1 Publication
Biological Process cellular response to fatty acid Source:Ensembl
Biological Process cellular response to gamma radiation Source:UniProtKB1 Publication
Biological Process cellular response to leukemia inhibitory factor Source:Ensembl
Biological Process cellular response to X-ray Source:GO_Central1 Publication
Biological Process DNA recombination Source:ProtInc1 Publication
Biological Process double-strand break repair Source:BHF-UCL1 Publication
Biological Process double-strand break repair via nonhomologous end joining Source:UniProtKB1 Publication
Biological Process hematopoietic stem cell differentiation Source:Ensembl
Biological Process hematopoietic stem cell proliferation Source:Ensembl
Biological Process innate immune response Source:UniProtKB-KW
Biological Process negative regulation of DNA-templated transcription Source:UniProtKB1 Publication
Biological Process negative regulation of t-circle formation Source:BHF-UCL1 Publication
Biological Process neurogenesis Source:Ensembl
Biological Process positive regulation of catalytic activity Source:BHF-UCL1 Publication
Biological Process positive regulation of neurogenesis Source:Ensembl
Biological Process positive regulation of protein kinase activity Source:CAFA1 Publication
Biological Process positive regulation of telomerase activity Source:BHF-UCL1 Publication
Biological Process positive regulation of telomere maintenance via telomerase Source:BHF-UCL1 Publication
Biological Process protein localization to chromosome, telomeric region Source:BHF-UCL1 Publication
Biological Process recombinational repair Source:ComplexPortal1 Publication
Biological Process regulation of smooth muscle cell proliferation Source:UniProtKB1 Publication
Biological Process regulation of telomere maintenance Source:BHF-UCL3 Publications
Biological Process response to xenobiotic stimulus Source:Ensembl
Biological Process small-subunit processome assembly Source:UniProtKB1 Publication
Biological Process telomere maintenance Source:GO_Central1 Publication
Cellular Location
Nucleus
Nucleus, nucleolus
Chromosome
PTM
ADP-ribosylated by PARP3.
Phosphorylated on serine residues. Phosphorylation by PRKDC may enhance helicase activity.
Sumoylated.
Ubiquitinated by RNF8 via 'Lys-48'-linked ubiquitination following DNA damage, leading to its degradation and removal from DNA damage sites (PubMed:22266820).
Ubiquitinated by RNF138, leading to remove the Ku complex from DNA breaks (PubMed:26502055).