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In Vitro Aggregation Assays Using Hyperphosphorylated Tau Protein
09:22

In Vitro Aggregation Assays Using Hyperphosphorylated Tau Protein

Published on: January 2, 2015

Changes in conformation of human neuronal tau during denaturation in formaldehyde solution

Chun-Lai Nie1, Wei Zhang, Dai Zhang

  • 1Lab of Visual Information Processing, Institute of Biophysics, Chinese Academy of Sciences, Beijing.

Protein and Peptide Letters
|January 11, 2005
PubMed

Insights

Formaldehyde alters human tau protein structure, increasing light scattering and forming hydrophobic cores. This formaldehyde-induced aggregation prevents enzymatic digestion, suggesting protein rigidity.

Area of Science:

  • Biochemistry
  • Neuroscience
  • Protein Chemistry

Background:

  • Human neuronal tau protein is implicated in neurodegenerative diseases.
  • Protein aggregation is a key pathological hallmark in tauopathies.
  • Understanding tau aggregation mechanisms is crucial for therapeutic development.

Purpose of the Study:

  • To investigate the structural changes in human tau protein induced by low concentrations of formaldehyde.
  • To assess the impact of formaldehyde on tau protein aggregation and its susceptibility to enzymatic degradation.

Main Methods:

  • Incubation of human neuronal tau with varying formaldehyde concentrations.
  • Measurement of light scattering intensity at 480 nm.
  • Fluorescence quenching using potassium iodide.
  • 8-anilino-1-naphthalenesulfonic acid (ANS) binding assay.
  • Enzymatic hydrolysis of native and formaldehyde-treated tau using earthworm fibrinolytic enzyme-II (EFE-II).

Main Results:

  • Formaldehyde treatment markedly increased light scattering of tau-40 solutions.
  • Fluorescent quenching constants decreased with increasing formaldehyde concentrations.
  • ANS binding assay indicated the formation of a hydrophobic core in formaldehyde-incubated tau polymers.
  • Formaldehyde-treated tau resisted digestion by EFE-II, unlike native tau.

Conclusions:

  • Low concentrations of formaldehyde induce significant structural changes in human tau, leading to aggregation.
  • Formaldehyde-induced tau aggregates exhibit increased rigidity and are resistant to enzymatic hydrolysis.
  • These findings provide insights into formaldehyde's role in protein aggregation and its potential implications in biological systems.

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