Biology subjects

Herlory, M.

Publications and source records attributed to Herlory, M..

3 recordsLinked to original sources

bioRxiv2026

Solvent-Isotope Effects in Biomolecular Phase Separation and Fibrillation of Disordered Proteins and Peptides

Heavy water (D2O) is widely used in biomolecular spectroscopy and imaging, often under the assumption that it is an inert replacement for H2O. However, D2O differs subtly in hydrogen-bonding, viscosity, and dielectric properties, which can alter biomolecular interactions and self-assembly. Here, we test how solvent isotope substitution modulates protein/peptide phase separation and amyloid formation in multiple intrinsically disordered systems. Using turbidity-based phase diagrams and microscopy, we quantify how D2O shifts protein-RNA complex coacervation boundaries and alters condensate morphology. Droplet recovery measurements indicate significant solvent-dependent changes in condensate material properties. We further evaluate amyloid formation kinetics, in the presence or absence of a cofactor, supported by orthogonal structural characterization, and assess the functional consequences of tau fibrils using a tau biosensor seeding assay with explicitly defined seed delivery conditions. Together, these results show that D2O can systematically bias liquid-liquid phase separation and aggregation readouts and should be treated as an active experimental variable rather than a neutral solvent substitute.

biophysics↗

bioRxiv2025

N-Linked Glycosylation as a Driver of Tau Pathology and Neuronal Transmission

N-Linked glycosylation of Tau is implicated in Alzheimers disease, yet how it influences Tau propagation and neuronal uptake remains unclear. Here, we use chemically defined N-glycoforms of 2N4R Tau and the K18 repeat domain to map how glycan site and structure reprogram Tau-polyanion binding, seeding, and entry into human neurons. Site-specific GlcNAc or high-mannose glycans at Asn359 or Asn410 remodel heparin and RNA binding kinetics in biolayer interferometry assays, revealing avidity-dominated, slow-off heparin interactions that are dampened by N-glycans and faster RNA interactions that can be potentiated by small GlcNAc modifications. Cross-seeding experiments show that N-glycosylation selectively tunes nucleation compatibility between Tau proteoforms; GlcNAc at Asn410 in full-length Tau and small glycans at Asn359 in K18 most strongly accelerate aggregation. In HEK293T FRET biosensor cells and iPSC-derived cortical neurons, N-glycans enhance or suppress seeding and pHrodo-reported uptake in a site- and glycan-dependent manner, with Asn410 glycosylation markedly potentiating cellular seeding. Pharmacological inhibition with atropine, dynasore, and cytochalasin D further indicates that N-glycans rebalance muscarinic, dynamin-dependent, and actin-dependent uptake routes. Together, these data establish N-linked glycosylation as a tunable regulator of Tau trafficking and prion-like spread, coupling extracellular receptor usage to intracellular cofactor engagement, and reveals druggable nodes in uptake.

neuroscience↗

bioRxiv2024

Post-Translational Modifications Control Phase Transitions of Tau

The self-assembly of Tau(297-391) into filaments, which mirror the structures observed in Alzheimers 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, thus facilitating the study of their roles in Tau pathology. Using transmission electron microscopy (TEM), cryo-electron microscopy (cryo-EM), and a range of optical microscopy techniques, we discovered that these modifications generally hinder the in vitro assembly of Tau into PHFs. Interestingly, while acetylations effect on Tau assembly displayed variability, either promoting or inhibiting phase transitions in the context of 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 fibrils rigid core are pivotal in the nucleation of PHFs. Moreover, in scenarios involving heparin-induced aggregation leading to the formation of heterogeneous aggregates, most AD-specific PTMs, except for K311, appeared to decelerate the aggregation process. The impact of acetylation on RNA-induced LLPS was notably site-dependent, exhibiting both facilitative and inhibitory effects, 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, enhancing our understanding of the molecular underpinnings of Tau pathology in AD and highlighting the critical role of PTMs located outside the ordered filament core in driving the self-assembly of Tau into PHF structures.

biophysics↗