First tau repeat domain binding to growing and taxol-stabilized microtubules, and serine 262 residue phosphorylation

Area of Science:

• Biochemistry
• Neuroscience
• Molecular Biology

Background:

• Tau phosphorylation is vital for microtubule stability and implicated in Alzheimer's disease pathogenesis.
• Understanding tau's interaction with microtubules is key to elucidating disease mechanisms.

Purpose of the Study:

• To investigate the molecular mechanisms of tau binding to microtubules.
• To characterize the binding parameters of the tau microtubule-binding motif (R1) and its phosphorylated form.

Main Methods:

• Synthesis of the R1 peptide, representing the first tau microtubule-binding motif.
• Thermodynamic characterization of tubulin assembly with R1 in vitro.
• Measurement of R1 binding parameters on growing and taxol-stabilized microtubules.

Main Results:

• The R1 peptide's binding parameters on microtubules were determined.
• Similar binding parameters were observed for R1 phosphorylated on Ser262.
• These findings suggest phosphorylation induces intramolecular rearrangements in tau.

Conclusions:

• Tau's Ser262 phosphorylation influences its interaction with microtubules indirectly.
• Intramolecular structural changes in tau, rather than direct binding alteration, are likely responsible for phosphorylation's effects.
• This provides new insights into tau's role in microtubule dynamics and Alzheimer's disease.