APTX
Domain
The histidine triad, also called HIT motif, forms part of the binding loop for the alpha-phosphate of purine mononucleotide.
The FHA-like domain mediates interaction with NCL; XRCC1 and XRCC4.
The HIT domain is required for enzymatic activity.
The C2H2-type zinc finger mediates DNA-binding.
Function
DNA-binding protein involved in single-strand DNA break repair, double-strand DNA break repair and base excision repair (PubMed:15044383, PubMed:15380105, PubMed:16964241, PubMed:17276982, PubMed:24362567). Resolves abortive DNA ligation intermediates formed either at base excision sites, or when DNA ligases attempt to repair non-ligatable breaks induced by reactive oxygen species (PubMed:16964241, PubMed:24362567). Catalyzes the release of adenylate groups covalently linked to 5'-phosphate termini, resulting in the production of 5'-phosphate termini that can be efficiently rejoined (PubMed:16964241, PubMed:17276982, PubMed:24362567). Also able to hydrolyze adenosine 5'-monophosphoramidate (AMP-NH(2)) and diadenosine tetraphosphate (AppppA), but with lower catalytic activity (PubMed:16547001). Likewise, catalyzes the release of 3'-linked guanosine (DNAppG) and inosine (DNAppI) from DNA, but has higher specific activity with 5'-linked adenosine (AppDNA) (By similarity).
Involvement in disease
Ataxia-oculomotor apraxia syndrome
AOA
An autosomal recessive syndrome characterized by early-onset cerebellar ataxia, oculomotor apraxia, early areflexia and late peripheral neuropathy.
None
The disease is caused by variants affecting the gene represented in this entry.
Tissue Specificity
Widely expressed; detected in liver, kidney and lymph node (at protein level) (PubMed:14755728). Isoform 1 is highly expressed in the cerebral cortex and cerebellum, compared to isoform 2 (at protein level) (PubMed:14755728). Widely expressed; detected throughout the brain, in liver, kidney, skeletal muscle, fibroblasts, lymphocytes and pancreas (PubMed:11586299, PubMed:11586300, PubMed:15276230).
Cellular localization
- Nucleus
- Nucleoplasm
- Nucleus
- Nucleolus
- Upon genotoxic stress, colocalizes with XRCC1 at sites of DNA damage (PubMed:15380105). Colocalizes with MDC1 at sites of DNA double-strand breaks (PubMed:20008512). Interaction with NCL is required for nucleolar localization (PubMed:16777843).
- Isoform 12
- Cytoplasm
Alternative names
AXA1, APTX, Aprataxin, Forkhead-associated domain histidine triad-like protein, FHA-HIT