Ataxin 3 (ATXN3) Antibody – Polyclonal

Machado-Joseph disease, also known as spinocerebellar ataxia-3, is an autosomal dominant neurologic disorder. The protein encoded by this gene contains (CAG)n repeats in the coding region, and the expansion of these repeats from the normal 13-36 to 68-79 is one cause of Machado-Joseph disease. There is a negative correlation between the age of onset and CAG repeat numbers. Alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Sep 2009]

ataxin-3: Deubiquitinating enzyme involved in protein homeostasis maintenance, transcription, cytoskeleton regulation, myogenesis and degradation of misfolded chaperone substrates. Binds long polyubiquitin chains and trims them, while it has weak or no activity against chains of 4 or less ubiquitins. Involved in degradation of misfolded chaperone substrates via its interaction with STUB1/CHIP: recruited to monoubiquitinated STUB1/CHIP, and restricts the length of ubiquitin chain attached to STUB1/CHIP substrates and preventing further chain extension. In response to misfolded substrate ubiquitination, mediates deubiquitination of monoubiquitinated STUB1/CHIP. Interacts with key regulators of transcription and represses transcription: acts as a histone- binding protein that regulates transcription. Defects in ATXN3 are the cause of spinocerebellar ataxia type 3 (SCA3); also known as Machado-Joseph disease (MJD). Spinocerebellar ataxia is a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCA3 belongs to the autosomal dominant cerebellar ataxias type I (ADCA I) which are characterized by cerebellar ataxia in combination with additional clinical features like optic atrophy, ophthalmoplegia, bulbar and extrapyramidal signs, peripheral neuropathy and dementia. The molecular defect in SCA3 is the a CAG repeat expansion in ATXN3 coding region. Longer expansions result in earlier onset and more severe clinical manifestations of the disease. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: Ubiquitin-specific protease; DNA repair, damage; Transcription regulation; Protease; EC 3.4.19.12

Chromosomal Location of Human Ortholog: 14q21

Cellular Component: cytoplasm; cytosol; endoplasmic reticulum membrane; mitochondrial matrix; mitochondrial membrane; nuclear inclusion body; nuclear matrix; nucleoplasm; nucleus

Molecular Function: ATPase binding; histone deacetylase activity; identical protein binding; omega peptidase activity; protein binding; ubiquitin protein ligase binding; ubiquitin-specific protease activity

Biological Process: actin cytoskeleton organization and biogenesis; intermediate filament cytoskeleton organization and biogenesis; microtubule cytoskeleton organization and biogenesis; misfolded or incompletely synthesized protein catabolic process; nervous system development; nucleotide-excision repair; proteasomal ubiquitin-dependent protein catabolic process; protein deubiquitination; regulation of transcription, DNA-dependent; synaptic transmission; transcription, DNA-dependent; ubiquitin-dependent protein catabolic process

Disease: Machado-joseph Disease