What are the primary components of neurofibrillary tangles?

What are the primary components of neurofibrillary tangles?

• A. abnormally processed beta-amyloid protein
• B. filaments of abnormally phosphorylated tau protein
• C. alpha-synuclein
• D. neurofilaments

Answer: (B)

Neurofibrillary tangles are intracellular aggregates comprised primarily of tau protein that has become abnormally phosphorylated. Tau normally helps stabilize microtubules in neurons, but when it is excessively phosphorylated it detaches from microtubules, misfolds, and assembles into filamentous structures inside the neuron. These filaments, called paired helical and straight filaments, accumulate and disrupt cellular function, contributing to neuronal death in diseases like Alzheimer’s. In contrast, beta-amyloid forms extracellular plaques, alpha-synuclein forms Lewy bodies in other disorders, and neurofilaments are structural components of the neuron not the primary constituents of tangles.

Neurofibrillary tangles are intracellular aggregates comprised primarily of tau protein that has become abnormally phosphorylated. Tau normally helps stabilize microtubules in neurons, but when it is excessively phosphorylated it detaches from microtubules, misfolds, and assembles into filamentous structures inside the neuron. These filaments, called paired helical and straight filaments, accumulate and disrupt cellular function, contributing to neuronal death in diseases like Alzheimer’s. In contrast, beta-amyloid forms extracellular plaques, alpha-synuclein forms Lewy bodies in other disorders, and neurofilaments are structural components of the neuron not the primary constituents of tangles.