Unsaturated Fatty Acid-Induced Conformational Transitions and Aggregation of the Repeat Domain of Tau.

Carlo Giorgio Barracchia,Roberto Tira,Luigi Bubacco,Michael Assfalg,Mariapina D’Onofrio,Francesca Parolini,Francesca Munari,Georgios A Spyroulias

doi:10.3390/molecules25112716

Carlo Giorgio Barracchia, Roberto Tira + Show 6 more

Open Access

https://doi.org/10.3390/molecules25112716

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Abstract

Background: The intrinsically disordered, amyloidogenic protein Tau associates with diverse classes of molecules, including proteins, nucleic acids, and lipids. Mounting evidence suggests that fatty acid molecules could play a role in the dysfunction of this protein, however, their interaction with Tau remains poorly characterized. Methods: In a bid to elucidate the association of Tau with unsaturated fatty acids at the sub-molecular level, we carried out a variety of solution NMR experiments in combination with circular dichroism and fluorescence measurements. Our study shows that Tau4RD, the highly basic four-repeat domain of Tau, associates strongly with arachidonic and oleic acid assemblies in a high lipid/protein ratio, perturbing their supramolecular states and itself undergoing time-dependent structural adaptation. The structural signatures of Tau4RD/fatty acid aggregates appear similar for arachidonic acid and oleic acid, however, they are distinct from those of another prototypical intrinsically disordered protein, α-synuclein, when bound to these lipids, revealing protein-specific conformational adaptations. Both fatty acid molecules are found to invariably promote the self-aggregation of Tau4RD and of α-synuclein. Conclusions: This study describes the reciprocal influence that Tau4RD and fatty acids exert on their conformational states, contributing to our understanding of fundamental aspects of Tau/lipid co-assembly.

Highlights

Tau is an axonal cytosolic protein initially reported to promote the assembly of tubulin and to stabilize the microtubule network, thereby supporting neuronal cell function [1,2]
We focused on the interaction of Tau4RD with arachidonic acid (ARA, all-cis-5,8,11,14-eicosatetraenoic acid), representing an abundant polyunsaturated fatty acids (FAs) in the brain, and oleic acid (OLA, cis-9-octadecenoic acid), a representative long-chain mono-unsaturated FA
The intrinsically disordered, amyloidogenic protein Tau associates with diverse classes of molecules, including proteins, nucleic acids, and lipids

Summary

Introduction

Tau is an axonal cytosolic protein initially reported to promote the assembly of tubulin and to stabilize the microtubule network, thereby supporting neuronal cell function [1,2]. Our study shows that Tau4RD , the highly basic four-repeat domain of Tau, associates strongly with arachidonic and oleic acid assemblies in a high lipid/protein ratio, perturbing their supramolecular states and itself undergoing time-dependent structural adaptation. The structural signatures of Tau4RD /fatty acid aggregates appear similar for arachidonic acid and oleic acid, they are distinct from those of another prototypical intrinsically disordered protein, α-synuclein, when bound to these lipids, revealing protein-specific conformational adaptations. Both fatty acid molecules are found to invariably promote the self-aggregation of Tau4RD and of α-synuclein. Conclusions: This study describes the reciprocal influence that Tau4RD and fatty acids exert on their conformational states, contributing to our understanding of fundamental aspects of Tau/lipid co-assembly

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Discussion

Conclusion