Exploring aggregation-inducers for tau protein

12/06/2023

Tau is a neuronal intrinsically disordered and also microtubule-associated protein, whose abnormal deposition in the brain is linked to numerous neurogenerative diseases. These Tauopathies include Alzheimer’s disease and frontotemporal dementia (with over 20 disorders). Several disease mutations in Tau, including P301L, impair Tau function (the binding and stabilization of microtubules) and also promote its pathological aggregation (both loss- and gain-of-function). The fibrillation of Tau in vitro has been extensively explored by Thioflavin T (ThT) fluorescence studies performed with the aggregation-prone K18 Tau fragment, comprising only the microtubule-binding domain. Moreover, the aggregation of the longest Tau isoform - 2N4R- in the presence of aggregation-inducers has been largely overlooked. Here, we investigated the effects of two anionic aggregation promoters - heparin and anionic lipid vesicles - in the fibrillation of wild-type (WT) and P301L 2N4R Tau proteins. Initially, both WT and P301L variants were recombinantly expressed and purified. Then, ThT fluorescence assays were carried out for both proteins in solution and in the presence of heparin or phosphatidylserine-containing membranes. Our assays show some variability in the absolute ThT signal, but globally our data indicate that heparin works as a stronger aggregation-promoter for both WT and P301L Tau than anionic lipid vesicles (here minor effects). Moreover, heparin has a higher aggregation effect in the P301L Tau protein.

Authors in the community:

• 

  C

  Carlota de Galrinho e Silva

  ist1102169

Supervisors of this institution:

• 

  A

  Ana Margarida Pereira de Melo

  ist90309

• 

  A

  Ana Margarida Nunes da Mata Pires de Azevedo

  ist30470

industrial-biotechnology - Industrial Biotechnology

eng - English

Instituto Superior Técnico