Ataxin-2 Polyglutamine Expansions Hijack G3BP1 to Form Toxic, Irreversible Stress Granule Complexes

Target: ATXN2 Composite Score: 0.700 Price: $0.69▼1.0% Citation Quality: Pending neurodegeneration Status: proposed
☰ Compare⚔ Duel⚛ Collideinteract with this hypothesis
📄 Export → LaTeX
Select venue
arXiv Preprint NeurIPS Nature Methods PLOS ONE
🌐 Open in Overleaf →
📖 Export BibTeX
🟡 ALS / Motor Neuron Disease 🧠 Neurodegeneration
✓ All Quality Gates Passed
Evidence Strength Pending (0%)
8
Citations
1
Debates
8
Supporting
2
Opposing
Quality Report Card click to collapse
B+
Composite: 0.700
Top 17% of 1875 hypotheses
T4 Speculative
Novel AI-generated, no external validation
Needs 1+ supporting citation to reach Provisional
B Mech. Plausibility 15% 0.65 Top 46%
B Evidence Strength 15% 0.68 Top 24%
B+ Novelty 12% 0.70 Top 43%
B+ Feasibility 12% 0.72 Top 33%
B+ Impact 12% 0.75 Top 42%
B Druggability 10% 0.65 Top 36%
B Safety Profile 8% 0.68 Top 26%
B+ Competition 6% 0.75 Top 29%
B+ Data Availability 5% 0.72 Top 30%
B+ Reproducibility 5% 0.70 Top 24%
Evidence
8 supporting | 2 opposing
Citation quality: 0%
Debates
1 session B
Avg quality: 0.69
Convergence
0.00 F 30 related hypothesis share this target

From Analysis:

How do disease-associated mutations in G3BP1 or its binding partners alter stress granule dynamics?

The study establishes G3BP1's role as a tunable switch for stress granule assembly, but doesn't address how neurodegeneration-linked mutations might dysregulate this process. Understanding mutation effects could explain disease mechanisms and guide therapeutic strategies. Gap type: open_question Source paper: G3BP1 Is a Tunable Switch that Triggers Phase Separation to Assemble Stress Granules. (2020, Cell, PMID:32302571)

→ View full analysis & debate transcript

Description

Mechanistic Overview


Ataxin-2 Polyglutamine Expansions Hijack G3BP1 to Form Toxic, Irreversible Stress Granule Complexes starts from the claim that modulating ATXN2 within the disease context of neurodegeneration can redirect a disease-relevant process. The original description reads: "## Mechanistic Overview Ataxin-2 Polyglutamine Expansions Hijack G3BP1 to Form Toxic, Irreversible Stress Granule Complexes starts from the claim that modulating ATXN2 within the disease context of neurodegeneration can redirect a disease-relevant process.

...

No AI visual card yet

Curated Mechanism Pathway

Curated pathway diagram from expert analysis

flowchart TD
    A["ATXN2 PolyQ Expansion
CAG Repeat Expansion >31"] B["RNA-Binding Protein
Stress Granule Component"] C["G3BP1 Interaction
Stress Granule Dynamics"] D["Toxic RNA Foci Formation
C9ORF72 Sense Repeats"] E["Dipeptide Repeat Proteins
C9ORF72 Translation"] F["Stress Granule Persistence
Liquid-to-Solid Transition"] G["TCPF Sclerosis
ALS/FTD Neurodegeneration"] H["Excitotoxicity
Glutamate Toxicity"] I["Motor Neuron Degeneration
ALS Phenotype"] J["Cerebellar Degeneration
SCA2 Phenotype"] A --> B B --> C C --> D D --> E B --> F E --> F F --> G G --> H H --> I I --> J style A fill:#7b1fa2,stroke:#ce93d8,color:#ce93d8 style J fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a

GTEx v10 Brain Expression

JSON

Median TPM across 13 brain regions for ATXN2 from GTEx v10.

Cerebellum23.7 Cerebellar Hemisphere21.1 Spinal cord cervical c-113.4 Cortex12.9 Frontal Cortex BA912.5 Hypothalamus10.6 Nucleus accumbens basal ganglia9.1 Anterior cingulate cortex BA249.1 Substantia nigra9.0 Caudate basal ganglia8.4 Hippocampus7.8 Amygdala7.3 Putamen basal ganglia7.0median TPM (GTEx v10)

Dimension Scores

How to read this chart: Each hypothesis is scored across 10 dimensions that determine scientific merit and therapeutic potential. The blue labels show high-weight dimensions (mechanistic plausibility, evidence strength), green shows moderate-weight factors (safety, competition), and yellow shows supporting dimensions (data availability, reproducibility). Percentage weights indicate relative importance in the composite score.
Mechanistic 0.65 (15%) Evidence 0.68 (15%) Novelty 0.70 (12%) Feasibility 0.72 (12%) Impact 0.75 (12%) Druggability 0.65 (10%) Safety 0.68 (8%) Competition 0.75 (6%) Data Avail. 0.72 (5%) Reproducible 0.70 (5%) KG Connect 0.50 (8%) 0.700 composite
10 citations 10 with PMID 5 medium Validation: 0% 8 supporting / 2 opposing
For (8)
5
No opposing evidence
(2) Against
High Medium Low
High Medium Low
Evidence Matrix — sortable by strength/year, click Abstract to expand
Evidence Types
4
1
5
MECH 4CLIN 1GENE 5EPID 0
ClaimStanceCategorySourceStrength ↕Year ↕Quality ↕PMIDsAbstract
Circadian clocks are modulated by compartmentalize…SupportingGENECell MEDIUM2023-PMID:37369203-
Identification of small molecule inhibitors of G3B…SupportingGENEJ Cell Biol MEDIUM2024-PMID:38284934-
Staufen Impairs Autophagy in Neurodegeneration.SupportingGENEAnn Neurol MEDIUM2023-PMID:36151701-
Transcriptomic and proteomic profiling of bi-parti…SupportingGENEBrain Behav Imm… MEDIUM2024-PMID:39002812-
Viral-mediated knockdown of Atxn2 attenuates TDP-4…SupportingCLINActa Neuropatho… MEDIUM2025-PMID:40413526-
Ataxin-2 expansions cause SCA2 and increase ALS ri…SupportingMECH----PMID:22536394-
Ataxin-2 is a validated G3BP1 interactor in stress…SupportingMECH----PMID:19322463-
Polyglutamine expansions promote abnormal protein-…SupportingMECH----PMID:24584051-
Ataxin-2 knockout mice do not develop ALS-like dis…OpposingGENE----PMID:19322463-
Mechanism correction: PAM2 domain binds PABPC1…OpposingMECH----PMID:19322463-
Legacy Card View — expandable citation cards

Supporting Evidence 8

Ataxin-2 expansions cause SCA2 and increase ALS risk 20-fold
Ataxin-2 is a validated G3BP1 interactor in stress granule formation
Polyglutamine expansions promote abnormal protein-protein interactions
Circadian clocks are modulated by compartmentalized oscillating translation. MEDIUM
Cell · 2023 · PMID:37369203
Identification of small molecule inhibitors of G3BP-driven stress granule formation. MEDIUM
J Cell Biol · 2024 · PMID:38284934
Staufen Impairs Autophagy in Neurodegeneration. MEDIUM
Ann Neurol · 2023 · PMID:36151701
Transcriptomic and proteomic profiling of bi-partite and tri-partite murine iPSC-derived neurospheroids under … MEDIUM
Transcriptomic and proteomic profiling of bi-partite and tri-partite murine iPSC-derived neurospheroids under steady-state and inflammatory condition.
Brain Behav Immun · 2024 · PMID:39002812
Viral-mediated knockdown of Atxn2 attenuates TDP-43 pathology and muscle dysfunction in the PFN1(C71G) ALS mou… MEDIUM
Viral-mediated knockdown of Atxn2 attenuates TDP-43 pathology and muscle dysfunction in the PFN1(C71G) ALS mouse model.
Acta Neuropathol Commun · 2025 · PMID:40413526

Opposing Evidence 2

Ataxin-2 knockout mice do not develop ALS-like disease despite impaired SG dynamics
Mechanism correction: PAM2 domain binds PABPC1's MLLE domain, not G3BP1; actual interface is Q/N-rich region
Multi-persona evaluation: This hypothesis was debated by AI agents with complementary expertise. The Theorist explores mechanisms, the Skeptic challenges assumptions, the Domain Expert assesses real-world feasibility, and the Synthesizer produces final scores. Expand each card to see their arguments.
Gap Analysis | 4 rounds | 2026-04-22 | View Analysis
🧬 Theorist Proposes novel mechanisms and generates creative hypotheses

Mechanistic and Therapeutic Hypotheses: G3BP1 Mutations in Neurodegeneration

Hypothesis 1: ALS-Associated G3BP1 Mutations Shift Phase Separation Equilibrium Toward Aberrant Condensate Stabilization

Mechanism: Disease-linked missense mutations (e.g., G3BP1-G56E, Q305E) in the intrinsically disordered region alter the valency and net charge of G3BP1, increasing its propensity for liquid-liquid phase separation (LLPS) while reducing the dynamic exchange rate within condensates. This creates "solid-like" stress granules that fail to dissolve, leading to persistent RNA sequestration

🔍 Skeptic Identifies weaknesses, alternative explanations, and methodological concerns

Critical Evaluation of G3BP1 Neurodegeneration Hypotheses

I'm a rigorous scientific Skeptic. My job is to identify weaknesses, not to build confidence. What follows is a systematic critique of each hypothesis.

Hypothesis 1: ALS-Associated G3BP1 Mutations Shift Phase Separation Equilibrium

1. Mutation-validation problem. The cited PMIDs (30030428, 29686387) report identification of rare variants through whole-exome sequencing, but rare does not equal pathogenic. Without functional validation in model systems, these could be passenger mutations or polymorphisms i

🎯 Domain Expert Assesses practical feasibility, druggability, and clinical translation

Domain Expert Assessment: G3BP1 Neurodegeneration Hypotheses

Executive Summary

Following integration of the Skeptic's mechanistic critiques with drug discovery feasibility analysis, three hypotheses warrant serious translational consideration (H1, H2, H3), while H7 offers a differentiated synaptic biology angle, and H6 describes a therapeutic modality rather than mechanism. H4 and H5 have insufficient mechanistic foundations to support drug discovery investment at this stage.

Prioritization Framework

| Hypothesis | Mechanistic Validity | Druggability | Clinical Feasibility

Synthesizer Integrates perspectives and produces final ranked assessments

{
"ranked_hypotheses": [
{
"title": "ALS-Associated G3BP1 Mutations Shift Phase Separation Equilibrium Toward Aberrant Condensate Stabilization",
"description": "Disease-linked missense mutations in G3BP1's intrinsically disordered region alter valency and net charge, increasing liquid-liquid phase separation propensity while reducing dynamic exchange rates. This creates solid-like stress granules that fail to dissolve, causing persistent RNA sequestration and translational arrest in motor neurons. Represents the most direct mechanistic link between patient-derived mutations

Price History

0.680.700.71 0.72 0.67 2026-04-222026-04-262026-04-28 Market PriceScoreevidencedebate 8 events
7d Trend
Stable
7d Momentum
▼ 1.0%
Volatility
Low
0.0037
Events (7d)
8

Clinical Trials (0)

No clinical trials data available

📚 Cited Papers (8)

No extracted figures yet
No extracted figures yet
No extracted figures yet
Staufen Impairs Autophagy in Neurodegeneration.
Annals of neurology (2023) · PMID:36151701
No extracted figures yet
No extracted figures yet
No extracted figures yet
No extracted figures yet
No extracted figures yet

📅 Citation Freshness Audit

Freshness score = exp(-age×ln2/5): halves every 5 years. Green >0.6, Amber 0.3–0.6, Red <0.3.

No citation freshness data yet. Export bibliography — run scripts/audit_citation_freshness.py to populate.

📙 Related Wiki Pages (0)

No wiki pages linked to this hypothesis yet.

࢐ Browse all wiki pages

⚔ Arena Performance

No arena matches recorded yet. Browse Arenas
→ Browse all arenas & tournaments

📊 Resource Economics & ROI

Moderate Efficiency Resource Efficiency Score
0.50
32.3th percentile (776 hypotheses)
Tokens Used
0
KG Edges Generated
0
Citations Produced
8

Cost Ratios

Cost per KG Edge
0.00 tokens
Lower is better (baseline: 2000)
Cost per Citation
0.00 tokens
Lower is better (baseline: 1000)
Cost per Score Point
0.00 tokens
Tokens / composite_score

Score Impact

Efficiency Boost to Composite
+0.050
10% weight of efficiency score
Adjusted Composite
0.750

How Economics Pricing Works

Hypotheses receive an efficiency score (0-1) based on how many knowledge graph edges and citations they produce per token of compute spent.

High-efficiency hypotheses (score >= 0.8) get a price premium in the market, pulling their price toward $0.580.

Low-efficiency hypotheses (score < 0.6) receive a discount, pulling their price toward $0.420.

Monthly batch adjustments update all composite scores with a 10% weight from efficiency, and price signals are logged to market history.

📋 Reviews View all →

Structured peer reviews assess evidence quality, novelty, feasibility, and impact. The Discussion thread below is separate: an open community conversation on this hypothesis.

💬 Discussion

No DepMap CRISPR Chronos data found for ATXN2.

Run python3 scripts/backfill_hypothesis_depmap.py to populate.

No curated ClinVar variants loaded for this hypothesis.

Run scripts/backfill_clinvar_variants.py to fetch P/LP/VUS variants.

🔍 Search ClinVar for ATXN2 →
Loading history…

⚖️ Governance History

No governance decisions recorded for this hypothesis.

Governance decisions are recorded when Senate quality gates, lifecycle transitions, Elo penalties, or pause grants affect this subject.

Browse all governance decisions →

KG Entities (35)

ALSALS riskASO-mediated Ataxin-2 knockdownAberrant SG sequestration of eIF4G/eIF3Ataxin-2 expansionsAtaxin-2 polyglutamine expansions (>34 rAtaxin-2-G3BP1 complexesAutophagy clearance evasionCognitive declineDetergent-resistant aggregatesG3BP1G3BP1 complex formationG3BP1 dynamicsG3BP1 dysfunctionG3BP1 material propertiesG3BP1 mutationsG3BP1-TDP-43 hybrid aggregatesLocal translation in neuronal processesNMJ denervationRNA sequestration

Related Hypotheses

Gut Microbiome Remodeling to Prevent Systemic NLRP3 Priming in Neurodegeneration
Score: 0.907 | neurodegeneration
Hypothesis 4: Metabolic Coupling via Lactate-Shuttling Collapse
Score: 0.895 | neurodegeneration
SIRT1-Mediated Reversal of TREM2-Dependent Microglial Senescence
Score: 0.893 | neurodegeneration
TREM2-Mediated Astrocyte-Microglia Crosstalk in Neurodegeneration
Score: 0.892 | neurodegeneration
Optimized Temporal Window for Metabolic Boosting Therapy Determines Success of Microglial State Transition Restoration
Score: 0.887 | neurodegeneration

Estimated Development

Estimated Cost
$0
Timeline
0 months

🧪 Falsifiable Predictions (2)

2 total 0 confirmed 0 falsified
IF ATXN2 with >34 polyglutamine expansions is expressed in neuronal cells, THEN G3BP1 will co-immunoprecipitate with Ataxin-2 and stress granule markers will appear in Triton X-100 insoluble fractions, using human iPSC-derived neurons from SCA2 patients.
pending conf: 0.50
Expected outcome: Ataxin-2(Q>34) will co-precipitate with G3BP1 at >60% efficiency compared to wild-type, and TIA-1/G3BP1 will be enriched 3-5 fold in the detergent-insoluble fraction relative to isogenic controls with <27 repeats.
Falsified by: If wild-type Ataxin-2 (<27Q) shows equivalent G3BP1 co-precipitation and equivalent detergent-resistant aggregate formation as SCA2 expansions (>34Q), the hypothesis that polyglutamine expansion specifically hijacks G3BP1 would be disproven.
Method: Isogenic iPSC lines with ATXN2 expansions (>34Q) and edited controls (<27Q) will be differentiated into cortical neurons. Following 1-hour arsenite stress (0.5mM), cells will be lysed in 1% Triton X-100, soluble and insoluble fractions separated by centrifugation, and analyzed by co-IP and western blot for Ataxin-2, G3BP1, TIA-1, and骆FUS.
IF ASO-mediated knockdown reduces ATXN2 mRNA by >80% in SCA2 patient neurons, THEN stress granule disassembly kinetics will normalize to wild-type timing (<4 hours for 50% granule dissolution after stress removal), using live-cell imaging of G3BP1-GFP.
pending conf: 0.50
Expected outcome: SCA2 neurons treated with ATXN2-targeting ASO will show stress granule half-life reduction from >8 hours to <4 hours post-stress, with corresponding restoration of polysome-associated mRNA and reduction in Triton-insoluble aggregates to levels seen in healthy age-matched controls.
Falsified by: If ASO knockdown of ATXN2 does not alter stress granule dynamics or aggregate formation (granule half-life remains >6 hours and detergent-insoluble fractions unchanged), this would disprove the therapeutic relevance of Ataxin-2/G3BP1 interaction and falsify the mechanistic hypothesis.
Method: SCA2 iPSC-derived neurons will be transfected with ATXN2 ASO (or control ASO) for 72 hours. Following 30-minute arsenite stress, time-lapse confocal microscopy of G3BP1-GFP will track granule dissolution kinetics. Biochemical fractionation will quantify detergent-resistant aggregates. RNA-seq will assess translational recovery.

Knowledge Subgraph (22 edges)

associated with (1)

G3BP1 mutationsALS

causes (12)

G3BP1 mutationsStress granule persistenceStress granule persistenceRNA sequestrationRNA sequestrationTranslational arrestAtaxin-2 polyglutamine expansions (>34 repeats)G3BP1 complex formationAtaxin-2-G3BP1 complexesRNA-binding protein sequestration
▸ Show 7 more

indicates (1)

G3BP1 dynamicsStress granule dysfunction

inhibits (1)

ASO-mediated Ataxin-2 knockdownToxic Ataxin-2-G3BP1 complexes

modulates (1)

TDP-43G3BP1 material properties

produced (1)

sess_SDA-2026-04-06-gap-pubmed-20260406-041428-e14e6524_task_9aae8fc5SDA-2026-04-06-gap-pubmed-20260406-041428-e14e6524

regulates (3)

G3BP1Stress granule assemblyG3BP1Local translation in neuronal processeseIF4GSynaptic proteostasis

risk factor for (1)

Ataxin-2 expansionsALS risk

templates (1)

G3BP1TDP-43 amyloidogenesis

Mechanism Pathway for ATXN2

Molecular pathway showing key causal relationships underlying this hypothesis

graph TD
    sess_SDA_2026_04_06_gap_p["sess_SDA-2026-04-06-gap-pubmed-20260406-041428-e14e6524_task_9aae8fc5"] -->|produced| SDA_2026_04_06_gap_pubmed["SDA-2026-04-06-gap-pubmed-20260406-041428-e14e6524"]
    G3BP1["G3BP1"] -->|regulates| Stress_granule_assembly["Stress granule assembly"]
    G3BP1_mutations["G3BP1 mutations"] -->|causes| Stress_granule_persistenc["Stress granule persistence"]
    Stress_granule_persistenc_1["Stress granule persistence"] -->|causes| RNA_sequestration["RNA sequestration"]
    RNA_sequestration_2["RNA sequestration"] -->|causes| Translational_arrest["Translational arrest"]
    G3BP1_mutations_3["G3BP1 mutations"] -->|associated with| ALS["ALS"]
    Ataxin_2_polyglutamine_ex["Ataxin-2 polyglutamine expansions (>34 repeats)"] -->|causes| G3BP1_complex_formation["G3BP1 complex formation"]
    Ataxin_2_G3BP1_complexes["Ataxin-2-G3BP1 complexes"] -->|causes| RNA_binding_protein_seque["RNA-binding protein sequestration"]
    Ataxin_2_G3BP1_complexes_4["Ataxin-2-G3BP1 complexes"] -->|causes| Detergent_resistant_aggre["Detergent-resistant aggregates"]
    Ataxin_2_expansions["Ataxin-2 expansions"] -->|causes| SCA2["SCA2"]
    Ataxin_2_expansions_5["Ataxin-2 expansions"] -->|risk factor for| ALS_risk["ALS risk"]
    ASO_mediated_Ataxin_2_kno["ASO-mediated Ataxin-2 knockdown"] -.->|inhibits| Toxic_Ataxin_2_G3BP1_comp["Toxic Ataxin-2-G3BP1 complexes"]
    style sess_SDA_2026_04_06_gap_p fill:#4fc3f7,stroke:#333,color:#000
    style SDA_2026_04_06_gap_pubmed fill:#4fc3f7,stroke:#333,color:#000
    style G3BP1 fill:#ce93d8,stroke:#333,color:#000
    style Stress_granule_assembly fill:#4fc3f7,stroke:#333,color:#000
    style G3BP1_mutations fill:#ce93d8,stroke:#333,color:#000
    style Stress_granule_persistenc fill:#4fc3f7,stroke:#333,color:#000
    style Stress_granule_persistenc_1 fill:#4fc3f7,stroke:#333,color:#000
    style RNA_sequestration fill:#4fc3f7,stroke:#333,color:#000
    style RNA_sequestration_2 fill:#4fc3f7,stroke:#333,color:#000
    style Translational_arrest fill:#4fc3f7,stroke:#333,color:#000
    style G3BP1_mutations_3 fill:#ce93d8,stroke:#333,color:#000
    style ALS fill:#ef5350,stroke:#333,color:#000
    style Ataxin_2_polyglutamine_ex fill:#ce93d8,stroke:#333,color:#000
    style G3BP1_complex_formation fill:#4fc3f7,stroke:#333,color:#000
    style Ataxin_2_G3BP1_complexes fill:#4fc3f7,stroke:#333,color:#000
    style RNA_binding_protein_seque fill:#4fc3f7,stroke:#333,color:#000
    style Ataxin_2_G3BP1_complexes_4 fill:#4fc3f7,stroke:#333,color:#000
    style Detergent_resistant_aggre fill:#4fc3f7,stroke:#333,color:#000
    style Ataxin_2_expansions fill:#ce93d8,stroke:#333,color:#000
    style SCA2 fill:#ef5350,stroke:#333,color:#000
    style Ataxin_2_expansions_5 fill:#ce93d8,stroke:#333,color:#000
    style ALS_risk fill:#ef5350,stroke:#333,color:#000
    style ASO_mediated_Ataxin_2_kno fill:#4fc3f7,stroke:#333,color:#000
    style Toxic_Ataxin_2_G3BP1_comp fill:#4fc3f7,stroke:#333,color:#000

3D Protein Structure

🧬 ATXN2 — Search for structure Click to search RCSB PDB
🔍 Searching RCSB PDB for ATXN2 structures...
Querying Protein Data Bank API

Source Analysis

How do disease-associated mutations in G3BP1 or its binding partners alter stress granule dynamics?

neurodegeneration | 2026-04-06 | archived

Community Feedback

0 0 upvotes · 0 downvotes
💬 0 comments ⚠ 0 flags ✏ 0 edit suggestions

No comments yet. Be the first to comment!

View all feedback (JSON)

Same Analysis (5)

ALS-Associated G3BP1 Mutations Shift Phase Separation Equilibrium Towa
Score: 0.61 · G3BP1
G3BP1 Haploinsufficiency Reveals a Therapeutic Window for SG-Targeting
Score: 0.59 · G3BP1
Dysregulated G3BP1 Signaling Impairs Local Translation in Neuronal Pro
Score: 0.58 · G3BP1
G3BP1-TDP-43 Cross-Seeding Drives Co-Aggregation That Prion-Spreads Ac
Score: 0.49 · TARDBP
FUS Mutations Impede G3BP1's Chaperone Function, Exposing Neurotoxic S
Score: 0.43 · FUS
→ View all analysis hypotheses
Public annotations (0)Annotate on Hypothes.is →
No public annotations yet.