Neurodegeneration, Proteostasis, and Cellular Stress
When molecular quality control fails
Proteostasis
Neurons rely on molecular chaperones, the ubiquitin-proteasome system, autophagy, and lysosomal degradation to maintain protein quality. Because neurons are long-lived and post-mitotic, errors in proteostasis can accumulate over time.
Pathology
Protein aggregation, mitochondrial dysfunction, axonal transport failure, and chronic inflammation are common convergent features of many neurodegenerative disorders.
Stress pathways
Cellular stress responses include the unfolded protein response, oxidative stress signaling, mitochondrial quality control, and inflammatory cascades. These pathways can initially be protective but become maladaptive when persistently activated.
Which system is primarily responsible for targeted degradation of many short-lived proteins?
The ubiquitin-proteasome system marks and degrades many short-lived proteins.
Correct answer: Ubiquitin-proteasome system
Name one cellular process that can be impaired in neurodegenerative disease.
Transport defects can deprive distal neurites of essential cargo and organelles.
Correct answer: Axonal transport
Proteostasis pathways
Proteasome
- Degrades ubiquitinated proteins
- Handles many soluble substrates
Autophagy
- Engulfs larger structures and aggregates
- Delivers cargo to lysosomes
Disease-relevant processes
Why are neurons especially vulnerable to proteostasis failure?
Their longevity and polarization make maintenance failures especially consequential.
Correct answer: They are long-lived and highly polarized
Evaluating a disease mechanism
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Step 1: Identify the vulnerable pathway or organelle.
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Step 2: Measure molecular pathology with biochemical and imaging assays.
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Step 3: Test causality using genetic or pharmacological perturbation.
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Step 4: Quantify rescue of cellular function.
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Step 5: Determine whether findings generalize across models.