TBK1 Loss Triggers eIF2α-Mediated Translational Repression Through Microglial SASP-Induced Integrated Stress Response in Motor Neurons
🧪 Overview
This hypothesis proposes that TBK1 loss-of-function mutations drive ALS pathogenesis through a two-step mechanism: first, TBK1-deficient microglia adopt a senescent state and release SASP factors (TNF-α, IL-1β, type I interferons) that act as paracrine stressors on motor neurons; second, these inflammatory signals chronically activate the Integrated Stress Response (ISR) in motor neurons, leading to pathological eIF2α phosphorylation and catastrophic repression of axonal protein synthesis. The mechanistic cascade begins with TBK1 haploinsufficiency disrupting microglial autophagy and NF-κB/IRF3 signaling, trapping microglia in an aged transcriptional state. The resulting SASP cytokines activate PKR and PERK kinases in neighboring motor neurons, elevating eIF2α phosphorylation from the normal 0.3-0.5 range to pathological levels of 0.7-0.9. This ISR overflow causes >70% reduction in synthesis of critical axonal and synaptic proteins (SNAP25, SYN1, VAMP1), leading to NMJ denervation and motor neuron death. The model predicts that TBK1-mutant ALS patients will show elevated microglial inflammatory signatures coupled with motor neuron ISR activation markers (ATF4, CHOP upregulation).
...🧬 Mechanism
Curated pathway from expert analysis
flowchart TD
A["dsDNA/dsRNA or Bacteria<br/>STING/MAVS Signal"]
B["TBK1 Activation<br/>IKK-epsilon Complex"]
C["IRF3 Phosphorylation<br/>Ser396 by TBK1"]
D["IRF3 Dimerization<br/>Nuclear Import"]
E["Type-I IFN Expression<br/>IFN-beta/IFN-alpha"]
F["Antiviral Defense<br/>ISG Upregulation"]
G["TBK1 Loss-of-Function<br/>ALS10 Mutations"]
H["OPTN/p62 Phosphorylation<br/>Selective Autophagy"]
A --> B
B --> C
B --> H
C --> D
D --> E
E --> F
G -.->|"impairs"| B
G -.->|"impairs"| H
style A fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
style F fill:#1b5e20,stroke:#81c784,color:#81c784
style G fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a⚖️ Evidence
No linked papers recorded for this hypothesis yet.
🏥 Translation
🧬 3D Protein Structure — TBK1
No curated PDB or AlphaFold mapping for TBK1 yet. Search RCSB →
💉 Clinical Trials
No clinical trials data linked to this hypothesis yet.
No curated ClinVar variants loaded for this hypothesis.
Run scripts/backfill_clinvar_variants.py to fetch P/LP/VUS variants.
No DepMap CRISPR Chronos data found for TBK1, EIF2S1.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
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▸Metadatasource: v1_phase_c_backfill · origin_type: gap_debate
| source | v1_phase_c_backfill |
| origin_type | gap_debate |
| _schema_version | 1 |