Beta-Amyloid
Aβ peptide
Normal Function
Uncertain—may play a role in synaptic function and plasticity.
Misfolded Form
Aggregates into oligomers and fibrils.
Location of Deposits
Extracellular plaques between neurons.
Associated Diseases
Alzheimer's disease, Down syndrome dementia.
Spread Pattern
Does not appear to spread neuron-to-neuron.
Tau
Microtubule-associated protein
Normal Function
Stabilizes microtubules and enables axonal transport.
Misfolded Form
Hyperphosphorylated; forms paired helical filaments.
Location of Deposits
Intracellular neurofibrillary tangles.
Associated Diseases
Alzheimer's, Pick's disease, PSP, CBD, and other tauopathies.
Spread Pattern
Spreads through neural networks in a predictable pattern.
Alpha-Synuclein
Synaptic vesicle protein
Normal Function
Regulates synaptic vesicle release and recycling.
Misfolded Form
Forms fibrils that aggregate into Lewy bodies.
Location of Deposits
Intracellular Lewy bodies and Lewy neurites.
Associated Diseases
Lewy body dementia, Parkinson's disease.
Spread Pattern
Appears to spread through connected brain regions.
What all three proteins have in common
- All are normally present in healthy brains.
- All undergo a conformational change (misfolding).
- All form aggregates that are toxic to neurons.
- All resist normal cellular clearance mechanisms.
- All accumulate progressively over years.
- All are targets for experimental therapies.
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