| 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. Required for double-strand break repair and V(D)J recombination. Also 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. 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. Binding to DNA may be mediated by XRCC6. 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. The XRCC5-XRRC6 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. 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. 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-XRRC6 dimer together with APEX1 acts as a negative regulator of transcription. In association with NAA15, the XRCC5-XRRC6 dimer binds to the osteocalcin promoter and activates osteocalcin expression. 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. Binding to U3 small nucleolar RNA, recruits PRKDC and XRCC5/Ku86 to the small-subunit processome. 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. |
| Protein Name | X-Ray Repair Cross-Complementing Protein 586 Kda Subunit Of Ku AntigenAtp-Dependent Dna Helicase 2 Subunit 2Atp-Dependent Dna Helicase Ii 80 Kda SubunitCtc Box-Binding Factor 85 Kda SubunitCtc85CtcbfDna Repair Protein Xrcc5Ku80Ku86Lupus Ku Autoantigen Protein P86Nuclear Factor IvThyroid-Lupus AutoantigenTlaaX-Ray Repair Complementing Defective Repair In Chinese Hamster Cells 5Double-Strand-Break Rejoining |
| Database Links | Reactome: R-HSA-164843Reactome: R-HSA-1834949Reactome: R-HSA-3270619Reactome: R-HSA-5693571Reactome: R-HSA-6798695 |
| Cellular Localisation | NucleusNucleolusChromosome |
| Alternative Protein Names | X-Ray Repair Cross-Complementing Protein 5 protein86 Kda Subunit Of Ku Antigen proteinAtp-Dependent Dna Helicase 2 Subunit 2 proteinAtp-Dependent Dna Helicase Ii 80 Kda Subunit proteinCtc Box-Binding Factor 85 Kda Subunit proteinCtc85 proteinCtcbf proteinDna Repair Protein Xrcc5 proteinKu80 proteinKu86 proteinLupus Ku Autoantigen Protein P86 proteinNuclear Factor Iv proteinThyroid-Lupus Autoantigen proteinTlaa proteinX-Ray Repair Complementing Defective Repair In Chinese Hamster Cells 5 proteinDouble-Strand-Break Rejoining proteinXRCC5 proteinG22P2 protein |
Information sourced from Uniprot.org
