APTX: DNA-binding protein involved in single-strand DNA break repair, double-strand DNA break repair and base excision repair. 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. 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. Also able to hydrolyze adenosine 5'- monophosphoramidate (AMP-NH(2)) and diadenosine tetraphosphate (AppppA), but with lower catalytic activity. Defects in APTX are the cause of ataxia-oculomotor apraxia syndrome (AOA). AOA is an autosomal recessive syndrome characterized by early-onset cerebellar ataxia, oculomotor apraxia, early areflexia and late peripheral neuropathy. 13 isoforms of the human protein are produced by alternative splicing.
Protein type: Nucleolus; RNA-binding; Phosphatase (non-protein); DNA repair, damage; EC 3.-.-.-; C2H2-type zinc finger protein
Chromosomal Location of Human Ortholog: 9p13.3
Cellular Component: nucleoplasm; nuclear chromatin; cytoplasm; nucleolus; nucleus; chromatin
Molecular Function: protein binding; DNA 5'-adenosine monophosphate hydrolase activity; phosphoglycolate phosphatase activity; polynucleotide 3'-phosphatase activity; metal ion binding; double-stranded RNA binding; double-stranded DNA binding; damaged DNA binding; phosphoprotein binding; protein N-terminus binding; chromatin binding
Biological Process: single strand break repair; dephosphorylation; response to hydrogen peroxide; double-strand break repair; regulation of protein stability; DNA catabolic process, exonucleolytic; response to DNA damage stimulus; DNA ligation
Disease: Ataxia, Early-onset, With Oculomotor Apraxia And Hypoalbuminemia
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