Recombinant Human Ku80 protein

Specifications

Form

Liquid

General info

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 : 11493912, PubMed : 12145306, PubMed : 7957065, PubMed : 8621488). Required for double-strand break repair and V(D)J recombination (PubMed : 11493912, PubMed : 12145306, PubMed : 7957065, PubMed : 8621488). Also has a role in chromosome translocation (PubMed : 11493912, PubMed : 12145306, PubMed : 7957065, PubMed : 8621488). The DNA helicase II complex binds preferentially to fork-like ends of double-stranded DNA in a cell cycle-dependent manner (PubMed : 11493912, PubMed : 12145306, PubMed : 7957065, PubMed : 8621488). It works in the 3'-5' direction (PubMed : 11493912, PubMed : 12145306, PubMed : 7957065, PubMed : 8621488). 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 : 11493912, PubMed : 12145306, PubMed : 7957065, PubMed : 8621488). Binding to DNA may be mediated by XRCC6 (PubMed : 11493912, PubMed : 12145306, PubMed : 7957065, PubMed : 8621488). The XRCC5-XRRC6 dimer acts as a 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 : 11493912, PubMed : 12145306, PubMed : 20383123, PubMed : 7957065, PubMed : 8621488). The XRCC5-XRRC6 dimer is probably involved in stabilizing broken DNA ends and bringing them together (PubMed : 12145306, PubMed : 20383123, PubMed : 7957065, PubMed : 8621488). The assembly of the DNA-PK complex to DNA ends is required for the NHEJ ligation step (PubMed : 12145306, PubMed : 20383123, PubMed : 7957065, PubMed : 8621488). 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).

Sequence similarities

Belongs to the ku80 family.

Post-translational modifications

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).

Subcellular localisation

Nucleus