PAXX
Domain
The N-terminus (residues 1-113) forms a head domain that is structurally related to those of XRCC4, XLF/NHEJ1, and SASS6.
Function
Non-essential DNA repair protein involved in DNA non-homologous end joining (NHEJ); participates in double-strand break (DSB) repair and V(D)J recombination (PubMed:25574025, PubMed:25670504, PubMed:25941166, PubMed:27705800). May act as a scaffold required for accumulation of the Ku heterodimer, composed of XRCC5/Ku80 and XRCC6/Ku70, at double-strand break sites and promote the assembly and/or stability of the NHEJ machinery (PubMed:25574025, PubMed:25670504, PubMed:25941166). Involved in NHEJ by promoting the ligation of blunt-ended DNA ends (PubMed:27703001). Together with NHEJ1/XLF, collaborates with DNA polymerase lambda (POLL) to promote joining of non-cohesive DNA ends (PubMed:25670504, PubMed:30250067). Constitutes a non-essential component of classical NHEJ: has a complementary but distinct function with NHEJ1/XLF in DNA repair (PubMed:27705800). Able to restrict infection by herpesvirus 1 (HSV-1) via an unknown mechanism (PubMed:29144403).
Post-translational modifications
Phosphorylation may inhibit interaction with the DNA-bound XRCC5/Ku80 and XRCC6/Ku70 heterodimer (Ku complex).
Sequence Similarities
Belongs to the XRCC4-XLF family. PAXX subfamily.
Cellular localization
- Nucleus
- Chromosome
- Predominantly localizes to the nucleus. Accumulates at sites of DNA damage generated by laser microirradiation.
- Cytoplasm
- (Microbial infection) Upon infection by herpesvirus 1 (HSV-1), it is partially translocated into the cytoplasm in an HSV-1-dependent manner.
Alternative names
C9orf142, XLS, PAXX, Protein PAXX, Paralog of XRCC4 and XLF, XRCC4-like small protein