Ataxin-2 (encoded by the ATXN2 gene) is a 1,318 amino acid RNA-binding protein with multifaceted roles in RNA metabolism, stress granule dynamics, and translational control. It ispathologically expanded for Spinocerebellar Ataxia Type 2 (SCA2), and intermediate polyglutamine (polyQ) repeat expansions in ATXN2 are a recognized genetic risk factor for amyotrophic lateral sclerosis (ALS) and possibly Parkinson's disease (PD). [1][2]
| Domain | Location | Function |
|---|---|---|
| Lsm domain | N-terminus (1-89) | RNA binding, spliceosome assembly |
| PAM2 motif | 90-150 | PABPC1 interaction |
| PolyQ tract | 162-227 | Variable (14-31 normal, 33-77 expanded) |
| PolyA-binding domain | 700-850 | mRNA binding |
| C-terminal | 900-1318 | Protein interactions |
Ataxin-2 is predominantly cytoplasmic and participates in:
SCA2 is caused by CAG repeat expansions in ATXN2 (>32 repeats), encoding an expanded polyQ tract:
| Feature | Details |
|---|---|
| Repeat length | 33-77 repeats (normal: 14-31) |
| Onset age | 30-50 years |
| Phenotype | Cerebellar ataxia, slow saccades, peripheral neuropathy |
| Neuropathology | Purkinje cell loss, pontine degeneration |
Intermediate ATXN2 repeat expansions (27-33 repeats) increase ALS risk:
Expanded ATXN2 repeats have been associated with PD risk:
WT ataxin-2 localizes to stress granules during cellular stress:
Mutant ataxin-2 disrupts this cycle, leading to:
Ataxin-2 interacts with:
| Approach | Stage | Target |
|---|---|---|
| ASO therapy | Preclinical | ATXN2 mRNA knockdown |
| CRISPR | Preclinical | Allele-specific editing |
| Stress granule modulators | Preclinical | Improve granule dynamics |
| Neuroprotective | Preclinical | Support neuronal survival |
Lastorio F, et al. Ataxin-2 in Parkinson's disease and dementia with Lewy bodies. Acta Neuropathol. 2020. ↩︎
Gonzalez M, et al. Ataxin-2 intermediate repeats and ALS risk. Neurology. 2019. ↩︎
Neuwald AF, et al. Lsm proteins in RNA processing. 1999. ↩︎
Kim J, et al. Ataxin-2 and translational control. 2019. ↩︎
Van耶格尔 M, et al. Ataxin-2 regulates stress granule dynamics. Nat Neurosci. 2020. ↩︎