The Effect of Site-Specific Acetylation Based Tau Mutations on Tau-Microtubule Associations

Abstract

Tau is an intrinsically disordered protein (IDP) crucial to neurons of the central nervous system (CNS) despite the lack of a stable tertiary structure. In neuronal axons one of the most well appreciated and studied functions of tau is the ability to stabilize the cytoskeletal protein, microtubules (MTs), by suppressing dynamic instability. It has been reported in the literature that alterations to the integrity of tau's structure can perturb tau-MT associations causing neurodegenerative tauopathies such as Alzheimer's and frontotemporal dementia with parksonism-17 (FTDP-17). While the most prevalent hypothesis alludes that misregulation of phosphorylation events can promote tau dysfunction, there is emerging evidence that other post-translational modifications such as acetylation can also perturb tau-MT associations and promote toxic tau-tau interactions. Thus, we hypothesize that post-translational modifications such as acetylation to specific residues in close proximity to the MT-binding region of tau may influence how tau mediates tau-MT and tau-tau associations. Furthermore, we demonstrate that purification of site-specific mutagenic tau is now readily achievable with expression of mutant recombinant tau containing a poly-His-tag. Here we probe tau-MT associations using transmission electron microscopy (TEM) and small angle x-ray scattering (SAXS).