Biology subjects

Moneo-Corcuera, D.

Publications and source records attributed to Moneo-Corcuera, D..

3 recordsLinked to original sources

bioRxiv2026

Mimicking two posttranslational modifications associated with oxidative stress affords phase separation of vimentin

Biomolecular condensates are membraneless compartments critical for the functional organization of cellular macromolecules in essential processes such as cell division, gene transcription or stress responses. We previously reported that vimentin filaments remodel into phase separated biomolecular condensates upon oxidative stress. This process requires vimentin single cysteine, C328, suggesting the involvement of oxidative modifications of this residue. Here, we aimed to generate vimentin condensates by inserting mutations mimicking posttranslational modifications associated with oxidative stress. In vimentin deficient cells, a cysteine oxidation mimetic mutant, vimentin C328D, formed only elongated particles or short filaments that evolved towards droplets upon serum deprivation or treatment with the oxidant diamide. Among vimentin posttranslational modifications rapidly responding to these stimuli, glycosylation confers filament stability whereas phosphorylation promotes disassembly. We observed that the O-deglycosylation inhibitor thiamet G, and the kinase inhibitors staurosporine and H-89, attenuated diamide-elicited vimentin C328D droplet formation, suggesting a potential glycosylation/phosphorylation interplay in this effect. Indeed, introducing phosphomimetic residues at certain single vimentin glycosylation and/or phosphorylation sites induced the formation of droplets, only if combined with the C328D mutation. In particular, the vimentin S49D,C328D mutant formed condensates that were reversibly dispersed by dilution through hypotonic shock. Therefore, mimicking C328 oxidation and S49 phosphorylation was sufficient to elicit vimentin phase separation. In vitro, purified vimentin S49D,C328D polymerized into a mixture of aberrant filaments and aggregates, which, in the presence of crowders, evolved towards paracrystals or clusters of beaded assemblies depending on pH. These findings highlight the role of C328 perturbations in the formation of biomolecular condensates and suggest a modulatory role of glycosylation/phosphorylation, thus shedding light on the processes regulating vimentin phase separation.

cell biology↗

bioRxiv2024

Formation of vimentin biomolecular condensate-like structures under oxidative stress

The intermediate filament protein vimentin performs a key role in cytoskeletal interplay and dynamics, and in cellular responses to stress. The vimentin monomer possesses a central -helical rod domain flanked by N- and C-terminal low complexity domains. Interactions between this type of domains play an important function in the formation of phase-separated biomolecular condensates, which in turn are critical for the organization of cellular components. Vimentin filaments undergo distinct and versatile reorganizations in response to diverse stimuli. Here we show that certain oxidants and electrophiles, including hydrogen peroxide and diamide, elicit the remodeling of vimentin filaments into small particles. Diamide in particular, induces a fast conversion of filaments into circular, motile dots, for which the presence of the single vimentin cysteine residue, C328, is critical. This effect is reversible, and filament reassembly can be noticed within minutes of removal of the oxidant. Diamide-elicited structures can recover fluorescence after photobleaching. Moreover, fusion of cells expressing differentially tagged vimentin allows the detection of dots positive for both tags, suggesting that vimentin dots can merge upon cell fusion. The aliphatic alcohol 1,6-hexanediol, known to alter interactions between low complexity domains, readily dissolves diamide-elicited vimentin dots at low concentrations, whereas at high concentrations it disrupts vimentin filaments. Taken together, these results indicate that vimentin oxidation can promote a fast and reversible filament remodeling into biomolecular condensate-like structures. Moreover, we hypothesize that this reorganization into droplet-like structures could play a protective role against irreversible damage by oxidative stress.

cell biology↗

bioRxiv2024

Key role of vimentin in the organization of the primary cilium

We previously reported the presence of the intermediate filament vimentin at the primary cilium of lung cancer epithelial cells. In this study we further demonstrate that vimentin is intimately intertwined with acetylated tubulin at this structure. Interestingly, although vimentin can be detected along the whole length of the primary cilium, phospho-serine 56 vimentin is found particularly enriched at its basal region in A549 lung cancer cells. Vimentin appears to play a pivotal role in ciliogenesis, since its depletion in MEF or in A549 cells results in a lower proportion of cells displaying primary cilia and recognizable basal bodies. Furthermore, the detectable cilia in vimentin depleted cells are shorter. In addition, the centriolar structure appears disrupted in vimentin deficient cells, as indicated by an abnormal distribution of {gamma}- and acetylated tubulin. Moreover, these cells display a defective organization of the pericentriolar material, characterized by a marked decrease in the levels of pericentrin and a diffuse distribution of Rab11. Taken together, our results show that vimentin is present at the primary cilium and suggest that it plays an important role in cilium structure and biogenesis, since its depletion leads to marked morphological defects and altered organization of key elements of this structure.

cell biology↗