Walczak Lab

Chemical Synthesis Reveals Pathogenic Role of N-Glycosylation in Microtubule-Associated Protein Tau Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the accumulation of tau protein aggregates. In this study, we investigated the effects of N-glycosylation on tau, focusing on ...

We're thrilled to share our new JACS publication revealing how N-glycosylation shapes tau protein behavior. Check it out at pubs.acs.org/doi/10.1021/...

A warm welcome to the first-year graduate students joining the Walczak lab - Himanshu, Zachary, Tania, Cat, Lily and Antawn!

Post-Translational Modifications Control Phase Transitions of Tau The self-assembly of Tau into filaments, which mirror the structures observed in Alzheimer’s disease (AD) brains, raises questions about the role of AD-specific post-translational modifications (PTMs) in the formation of paired helical filaments (PHFs). To investigate this, we developed a synthetic approach to produce Tau(291–391) featuring N-acetyllysine, phosphoserine, phosphotyrosine, and N-glycosylation at positions commonly modified in post-mortem AD brains. Using various electron and optical microscopy techniques, we discovered that these modifications generally hinder the in vitro assembly of Tau into PHFs. Interestingly, while acetylation’s effect on Tau assembly displayed variability, either promoting or inhibiting phase transitions in cofactor-free aggregation, heparin-induced aggregation, and RNA-mediated liquid–liquid phase separation (LLPS), phosphorylation uniformly mitigated these processes. Our observations suggest that PTMs, particularly those situated outside the rigid core, are pivotal in the nucleation of PHFs. Moreover, with heparin-induced aggregation leading to the formation of heterogeneous aggregates, most AD-specific PTMs appeared to decelerate aggregation. The impact of acetylation on RNA-induced LLPS was notably site-dependent, whereas phosphorylation consistently reduced LLPS across all proteoforms examined. These insights underscore the complex interplay between site-specific PTMs and environmental factors in modulating Tau aggregation kinetics, highlighting the role of PTMs located outside the ordered filament core in driving the self-assembly.

A new paper from our lab in ACS Cent Sci!

pubs.acs.org/doi/10.1021/...

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