APTX Blocking Peptide

This gene encodes a member of the histidine triad (HIT) superfamily. The encoded protein may play a role in single-stranded DNA repair through its nucleotide-binding activity and its diadenosine polyphosphate hydrolase activity. Mutations in this gene have been associated with ataxia-ocular apraxia. Alternatively spliced transcript variants have been identified for this gene.[provided by RefSeq, Aug 2010]

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: C2H2-type zinc finger protein; EC 3.-.-.-; Phosphatase (non-protein); DNA repair, damage; RNA-binding; Nucleolus

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 DNA binding; double-stranded RNA binding; damaged DNA binding; protein N-terminus binding; phosphoprotein 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