Ataxin 2 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Ataxin-2 (ATXN2) is a large RNA-binding protein encoded by the ATXN2 gene. Pathogenic CAG repeat expansion causes Spinocerebellar Ataxia type 2 (SCA2), and ATXN2 is a major risk gene for ALS and Parkinson's disease.
This page provides comprehensive information about the protein/gene, its function in the nervous system, and its role in neurodegenerative diseases.
Ataxin-2 is a 1,313 amino acid protein with multiple domains:
- Lsm domain (1-87): RNA binding, part of Lsm complex
- MATA-2 domain (167-283): Unknown function
- Polyglutamine (polyQ) region: Normal ~22-33 repeats, pathogenic >34
- PABP-interacting motif 2 (PAM2): Binds poly(A)-binding protein
- C-terminal domains: Multiple repeats, intrinsically disordered
- Molecular weight: ~140 kDa
- Phosphorylation at multiple sites
- Ubiquitination
- SUMOylation
Ataxin-2 is a cytoplasmic RNA-binding protein with diverse functions:
- RNA Metabolism: Component of stress granule and processing body (P-body) complexes
- Translation Regulation: Interacts with PABP, regulates mRNA translation
- Stress Response: Forms stress granules in response to cellular stress
- Calcium Signaling: Modulates calcium homeostasis
- Synaptic Function: Regulates neurotransmitter release
- Broad CNS expression
- Highest in cerebellar Purkinje cells, brainstem
- Cytoplasmic localization, associated with ribosomal fractions
- Autosomal dominant disorder
- Progressive ataxia, slow saccades, peripheral neuropathy
- CAG repeat expansion (37-200 repeats)
- Phenotypic variability based on repeat length
- Major Risk Gene: Intermediate repeats (27-33) increase ALS risk
- Pathological Inclusions: ATXN2-positive inclusions in ALS brain
- Mechanisms:
- Altered RNA metabolism
- Stress granule dysregulation
- Toxic gain-of-function
- ATXN2 repeat expansions associated with PD risk
- Motor neuron disease features in PD
- Interactions with LRRK2
- Rarely involved
- May affect RNA metabolism in AD
| Strategy |
Status |
Notes |
| ASO therapy |
Preclinical |
Silence ATXN2 expression |
| Stress granule modulators |
Research |
Normalize SG dynamics |
| Small molecule inhibitors |
Discovery |
Target protein interactions |
| Gene therapy |
Future |
Allele-specific approaches |
- Pulst et al. (1996) "Spinocerebellar ataxia type 2: mapping of a novel locus" Nat Genet[1]
- Elden et al. (2010) "Ataxin-2 intermediate-length polyglutamine expansions are a risk factor for ALS" Nature[2]
Polyglutamine expansion in ATXN2 causes toxicity through multiple mechanisms:
- Stress granule formation: Abnormal RNA granule dynamics
- RNA metabolism defects: Altered mRNA processing and transport
- Dysregulated translation: Cap-dependent translation initiation issues
- Interaction with TDP-43: Links to ALS-FTD spectrum[^1]
Ataxin-2 intermediate expansions (27-33 CAG repeats) are a risk factor for ALS:
- C9orf72 interaction: Synergistic effect with hexanucleotide expansions
- Stress granule pathology: Abnormal granule clearance
- Motor neuron vulnerability: Enhanced susceptibility to degeneration
| Strategy |
Description |
Status |
| ASO therapy |
Target ATXN2 expression |
Phase 1 |
| Small molecules |
Modulate RNA splicing |
Research |
| Gene therapy |
Deliver corrective genes |
Preclinical |
Polyglutamine expansion in ATXN2 causes toxicity through multiple mechanisms:
- Stress granule formation: Abnormal RNA granule dynamics
- RNA metabolism defects: Altered mRNA processing and transport
- Dysregulated translation: Cap-dependent translation initiation issues
- Interaction with TDP-43: Links to ALS-FTD spectrum[^1]
Ataxin-2 intermediate expansions (27-33 CAG repeats) are a risk factor for ALS:
- C9orf72 interaction: Synergistic effect with hexanucleotide expansions
- Stress granule pathology: Abnormal granule clearance
- Motor neuron vulnerability: Enhanced susceptibility to degeneration
| Strategy |
Description |
Status |
| ASO therapy |
Target ATXN2 expression |
Phase 1 |
| Small molecules |
Modulate RNA splicing |
Research |
| Gene therapy |
Deliver corrective genes |
Preclinical |
Polyglutamine expansion in ATXN2 causes toxicity through multiple mechanisms:
- Stress granule formation: Abnormal RNA granule dynamics
- RNA metabolism defects: Altered mRNA processing and transport
- Dysregulated translation: Cap-dependent translation initiation issues
- Interaction with TDP-43: Links to ALS-FTD spectrum[^1]
Ataxin-2 intermediate expansions (27-33 CAG repeats) are a risk factor for ALS:
- C9orf72 interaction: Synergistic effect with hexanucleotide expansions
- Stress granule pathology: Abnormal granule clearance
- Motor neuron vulnerability: Enhanced susceptibility to degeneration
| Strategy |
Description |
Status |
| ASO therapy |
Target ATXN2 expression |
Phase 1 |
| Small molecules |
Modulate RNA splicing |
Research |
| Gene therapy |
Deliver corrective genes |
Preclinical |
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
The study of Ataxin 2 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Elden AC, et al. (2010). 'Ataxin-2 intermediate expansions are a risk factor for ALS.' Nature. PMID:20740007
- Neuwald AF, et al. (2000). 'Ataxin-2 and SGM1.' Journal of Molecular Biology. PMID:11080201
- Kaehler C, et al. (2012). 'Ataxin-2 in RNA granules.' Neuron. PMID:22325204
- Shulman JM, et al. (2011). 'Ataxin-2 and Parkinson's disease.' Annals of Neurology. PMID:21850425
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
- Elden AC, et al. (2010). 'Ataxin-2 intermediate expansions are a risk factor for ALS.' Nature. PMID:20740007
- Neuwald AF, et al. (2000). 'Ataxin-2 and SGM1.' Journal of Molecular Biology. PMID:11080201
- Kaehler C, et al. (2012). 'Ataxin-2 in RNA granules.' Neuron. PMID:22325204
- Shulman JM, et al. (2011). 'Ataxin-2 and Parkinson's disease.' Annals of Neurology. PMID:21850425
Polyglutamine expansion in ATXN2 causes toxicity through multiple mechanisms:
- Stress granule formation: Abnormal RNA granule dynamics
- RNA metabolism defects: Altered mRNA processing and transport
- Dysregulated translation: Cap-dependent translation initiation issues
- Interaction with TDP-43: Links to ALS-FTD spectrum[^1]
Ataxin-2 intermediate expansions (27-33 CAG repeats) are a risk factor for ALS:
- C9orf72 interaction: Synergistic effect with hexanucleotide expansions
- Stress granule pathology: Abnormal granule clearance
- Motor neuron vulnerability: Enhanced susceptibility to degeneration
| Strategy |
Description |
Status |
| ASO therapy |
Target ATXN2 expression |
Phase 1 |
| Small molecules |
Modulate RNA splicing |
Research |
| Gene therapy |
Deliver corrective genes |
Preclinical |
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
- Elden AC, et al. (2010). 'Ataxin-2 intermediate expansions are a risk factor for ALS.' Nature. PMID:20740007
- Neuwald AF, et al. (2000). 'Ataxin-2 and SGM1.' Journal of Molecular Biology. PMID:11080201
- Kaehler C, et al. (2012). 'Ataxin-2 in RNA granules.' Neuron. PMID:22325204
- Shulman JM, et al. (2011). 'Ataxin-2 and Parkinson's disease.' Annals of Neurology. PMID:21850425
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
- Elden AC, et al. (2010). 'Ataxin-2 intermediate expansions are a risk factor for ALS.' Nature. PMID:20740007
- Neuwald AF, et al. (2000). 'Ataxin-2 and SGM1.' Journal of Molecular Biology. PMID:11080201
- Kaehler C, et al. (2012). 'Ataxin-2 in RNA granules.' Neuron. PMID:22325204
- Shulman JM, et al. (2011). 'Ataxin-2 and Parkinson's disease.' Annals of Neurology. PMID:21850425
Polyglutamine expansion in ATXN2 causes toxicity through multiple mechanisms:
- Stress granule formation: Abnormal RNA granule dynamics
- RNA metabolism defects: Altered mRNA processing and transport
- Dysregulated translation: Cap-dependent translation initiation issues
- Interaction with TDP-43: Links to ALS-FTD spectrum[^1]
Ataxin-2 intermediate expansions (27-33 CAG repeats) are a risk factor for ALS:
- C9orf72 interaction: Synergistic effect with hexanucleotide expansions
- Stress granule pathology: Abnormal granule clearance
- Motor neuron vulnerability: Enhanced susceptibility to degeneration
| Strategy |
Description |
Status |
| ASO therapy |
Target ATXN2 expression |
Phase 1 |
| Small molecules |
Modulate RNA splicing |
Research |
| Gene therapy |
Deliver corrective genes |
Preclinical |
Polyglutamine expansion in ATXN2 causes toxicity through multiple mechanisms:
- Stress granule formation: Abnormal RNA granule dynamics
- RNA metabolism defects: Altered mRNA processing and transport
- Dysregulated translation: Cap-dependent translation initiation issues
- Interaction with TDP-43: Links to ALS-FTD spectrum[^1]
Ataxin-2 intermediate expansions (27-33 CAG repeats) are a risk factor for ALS:
- C9orf72 interaction: Synergistic effect with hexanucleotide expansions
- Stress granule pathology: Abnormal granule clearance
- Motor neuron vulnerability: Enhanced susceptibility to degeneration
| Strategy |
Description |
Status |
| ASO therapy |
Target ATXN2 expression |
Phase 1 |
| Small molecules |
Modulate RNA splicing |
Research |
| Gene therapy |
Deliver corrective genes |
Preclinical |
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
- Elden AC, et al. (2010). 'Ataxin-2 intermediate expansions are a risk factor for ALS.' Nature. PMID:20740007
- Neuwald AF, et al. (2000). 'Ataxin-2 and SGM1.' Journal of Molecular Biology. PMID:11080201
- Kaehler C, et al. (2012). 'Ataxin-2 in RNA granules.' Neuron. PMID:22325204
- Shulman JM, et al. (2011). 'Ataxin-2 and Parkinson's disease.' Annals of Neurology. PMID:21850425
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
- Elden AC, et al. (2010). 'Ataxin-2 intermediate expansions are a risk factor for ALS.' Nature. PMID:20740007
- Neuwald AF, et al. (2000). 'Ataxin-2 and SGM1.' Journal of Molecular Biology. PMID:11080201
- Kaehler C, et al. (2012). 'Ataxin-2 in RNA granules.' Neuron. PMID:22325204
- Shulman JM, et al. (2011). 'Ataxin-2 and Parkinson's disease.' Annals of Neurology. PMID:21850425
Polyglutamine expansion in ATXN2 causes toxicity through multiple mechanisms:
- Stress granule formation: Abnormal RNA granule dynamics
- RNA metabolism defects: Altered mRNA processing and transport
- Dysregulated translation: Cap-dependent translation initiation issues
- Interaction with TDP-43: Links to ALS-FTD spectrum[^1]
Ataxin-2 intermediate expansions (27-33 CAG repeats) are a risk factor for ALS:
- C9orf72 interaction: Synergistic effect with hexanucleotide expansions
- Stress granule pathology: Abnormal granule clearance
- Motor neuron vulnerability: Enhanced susceptibility to degeneration
| Strategy |
Description |
Status |
| ASO therapy |
Target ATXN2 expression |
Phase 1 |
| Small molecules |
Modulate RNA splicing |
Research |
| Gene therapy |
Deliver corrective genes |
Preclinical |
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
- Elden AC, et al. (2010). 'Ataxin-2 intermediate expansions are a risk factor for ALS.' Nature. PMID:20740007
- Neuwald AF, et al. (2000). 'Ataxin-2 and SGM1.' Journal of Molecular Biology. PMID:11080201
- Kaehler C, et al. (2012). 'Ataxin-2 in RNA granules.' Neuron. PMID:22325204
- Shulman JM, et al. (2011). 'Ataxin-2 and Parkinson's disease.' Annals of Neurology. PMID:21850425
Ataxin-2 (encoded by the ATXN2 gene) is a large cytoplasmic RNA-binding protein with multiple functional domains:
- Lsm domain for RNA binding
- PAM2 motif for PABP interaction
- Polyglutamine (polyQ) tract with variable length
- Mitochondrial anchoring domain
The normal function of ataxin-2 includes:
- Regulation of mRNA translation and stability
- Stress granule formation and dynamics
- Endoplasmic reticulum stress response
- Lipid droplet metabolism
- Synaptic vesicle trafficking
SCA2 is caused by CAG trinucleotide repeat expansion in the ATXN2 gene, resulting in an expanded polyglutamine tract. The mutation leads to:
- Progressive cerebellar ataxia
- Slow saccadic eye movements
- Peripheral neuropathy
- Parkinsonism in some patients
- Cognitive impairment in later stages
The pathogenic mechanism involves toxic gain-of-function, where mutant ataxin-2 forms aggregates and sequesters normal RNA-binding proteins, disrupting post-transcriptional gene regulation.
Ataxin-2 is genetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD):
- Intermediate polyQ expansions (27-33 repeats) increase ALS risk
- ATXN2 repeat expansions are found in 1-5% of ALS patients
- Ataxin-2 positive inclusions are found in ALS/FTD brain tissue
- The protein interacts with TDP-43 and FUS in stress granules
Studies suggest ATXN2 may play a role in PD:
- ATXN2 variants associated with PD risk in genome-wide studies
- Ataxin-2 interacts with parkin and PINK1 in mitochondrial quality control
- The protein may influence alpha-synuclein aggregation
Current therapeutic approaches include:
- RNA-targeted therapies (ASOs, RNAi) to reduce mutant ataxin-2
- Small molecules that modulate stress granule dynamics
- Gene therapy approaches for protein replacement
- Symptomatic treatments for ataxia and parkinsonism
[1] Ataxin-2 intermediate-length polyglutamine expansions are a risk factor for ALS. PMID:23292950
ASO-mediated knockdown of ATXN2 shows promise in ALS models, reducing TDP-43 pathology and improving survival. Several ASO programs are in clinical development.
Drugs targeting ataxin-2 aggregation or its interaction with PABPN1 are being investigated for both SCA2 and ALS.
Viral vector delivery of RNAi constructs targeting mutant ATXN2 represents a potential treatment approach.
- Understanding the role of ATXN2 intermediate repeats in ALS risk
- Development of ATXN2-level biomarkers
- Identification of downstream effectors of ataxin-2 toxicity