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DNA repair protein XRCC4; X-ray repair cross-complementing protein 4 (XRCC4)
Function:
- role in DNA non-homologous end joining (NHEJ) required for double-strand break repair & V(D)J recombination
- binds to DNA & to DNA ligase IV (LIG4)
- the LIG4-XRCC4 complex is responsible for the NHEJ ligation step, & XRCC4 enhances the joining activity of LIG4
- binding of the LIG4-XRCC4 complex to DNA ends is dependent on the assembly of the DNA-dependent protein kinase complex DNA-PK to these DNA ends
- phosphorylated by PRKDC; phosphorylation seems not to be necessary for binding to DNA
- phosphorylation by CK2 promotes interaction with APTX
- monoubiquitinated
- sumoylation at Lys-210 is required for nuclear localization & recombination efficiency; has no effect on ubiquitination
- homodimer & homotetramer in solution
- homodimer associates with LIG4, & the LIG4-XRCC4 complex associates in a DNA-dependent manner with the DNA-PK complex formed by the Ku p70/p86 dimer (G22P1/G22P2) & PRKDC
- seems to interact directly with PRKDC but not with the Ku p70/86 dimer
- interacts with XLF/cernunnos
- interacts with APTX & APLF
Structure: belongs to the XRCC4 family
Compartment: nucleus
Alternative splicing: named isoforms=3
Expression: widely expressed
Related
XRCC4 gene (X-ray repair, complementing defective repair in Chinese hamster cells-4)
General
nuclear protein
phosphoprotein
Properties
SIZE: entity length = 336 aa
MW = 38 kD
COMPARTMENT: cell nucleus
MOTIF: coiled coil {131-165}
LIG4 interaction {180-213}
MOTIF: coiled coil {184-212}
Ser phosphorylation site {S232}
Thr phosphorylation site {T233}
Ser phosphorylation site {S260}
Ser phosphorylation site {S320}
Ser phosphorylation site {S327}
Ser phosphorylation site {S328}
Database Correlations
OMIM 194363
UniProt Q13426
Pfam PF06632
Entrez Gene 7518
Kegg hsa:7518
References
- UniProt :accession Q13426
- NIEHS-SNPs
http://egp.gs.washington.edu/data/xrcc4/