Thread by @LashuelLab

Check out our latest paper on @biorxivpreprint!

Phosphorylation of the overlooked #tyrosine 310 regulates the structure, #aggregation, and #microtubule- and #lipid-binding properties of #Tau

biorxiv.org/content/10.110…

Short #thread!

#AcademicTwitter #biochemistry #threadstory

Tau misfolding and aggregation are implicated in tauopathies such as #Alzheimers and #PSP. Tau is extensively post-translationally modified and aberrant pattern of PTMs are found in disease. Tyrosine PTMs have received the least attention, especially Y310.

Tau has 5 tyrosines, and Y310 is in the crucial position within the aggregation-prone MT- and lipid-binding repeat domain. It compacts and folds into beta-sheet structure. We asked:

How would addition of bulky negatively charged phosphogroups to tyrosines impact Tau properties?

We used in vitro phosphorylation by c-Abl and site-specific mutagenesis to study impact of all or specific tyrosine phosphorylation on Tau structure and properties by NMR, biochemical and functional assays.

We found

1. c-Abl is effective tool to produce large quantities (in milligram range, we produced 10mg/protein here) of in vitro phosphorylated Tau.

2. Phosphorylation of Y310 impacts structure of Tau repeat domain and underlies the inhibitory effect on Tau aggregation.

3. Phosphorylation of 5 Tau tyrosines significantly inhibit Tau aggregation depending on the site and stochiometry, with synergistic effects of phospho-tyrosines.

4. Phosphorylation of tyrosines reduces Tau affinity to microtubules and negatively-charged lipid vesicles.

5. Phosphorylation of Y310 plays key role in reduced Tau MT- and lipid-binding by impacting structure of the Tau repeat domain.

In summary, a) phosphorylation of multiple Tau tyrosines inhibits Tau aggregation through cumulative effects, and b) phosphorylation of Y310 is key determinant of Tau aggregation, MT- and lipid-binding in vitro through its impact on the structural properties of Tau repeat domain.

What is the importance?
Tau tyrosine phosphorylation is found in normal and diseased brain. Although Tau phosphorylation predominantly associated with Tau aggregation, we show that site-specificity is crucial, with pY310 leading to MT detachment, but preventing Tau fibrillization

This allows for more detailed understanding of Tau PTM effects on its properties, allowing us to scrupulously decouple Tau MT- and lipid-binding from amyloid fibrillization pathway. Specific patterns of Tau PTMs may prevent Tau amyloidogenicity, with Y310 paving the way.

Our study reinforces the importance of different Tau PTMs on its structural and functional properties. Tyrosine modifications may present a novel target for disease-modifying therapies implicating Tau aggregation.

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