Biology subjects

Unterauer, E. M.

Publications and source records attributed to Unterauer, E. M..

3 recordsLinked to original sources

bioRxiv2024

Structural diversity of Arc oligomers within the excitatory synapse

The Activity-Regulated Cytoskeleton-Associated protein (Arc), is pivotal to mediate plasticity responses in neuronal cells. In vitro studies suggest its ability to form high- and low-order oligomers, which are involved in neuronal trafficking. Despite its important functions, no direct observation of Arc oligomers in cells has been presented due to its highly regulated spatiotemporal expression, the small size of the structures, the lack of appropriate labelling strategies and the background associated to free diffusing cytosolic proteins. Here, we apply super resolution microscopy to observe Arc oligomeric states in cellular environment with focus on the excitatory synapse. In cells, we provide the first evidence of Arc high-order oligomers; we uncovered intermolecular interactions of Arc, its tendency to form liquid condensates and interaction with lipid bilayers. Arc high-order oligomers affect AMPA receptor surface levels. Together, our observations suggest a model by which Arc oligomerization mediates plasma membrane negative curvature favoring AMPA receptors endocytosis.

neuroscience↗

bioRxiv2023

POU5F1B is a human-restricted ROCK inhibitor-sensitive oncoprotein that restructures membrane nanodomains to increase cell adhesion

Evolution confers new species with distinctive biological features that can translate in either purely mechanistic speciation or novel phenotypes. Retrotransposition in the last Hominidae common ancestor of the pluripotency regulator POU5F1/OCT4 led to human POU5F1B, which promotes gastrointestinal cancer growth and metastasis through unknown mechanisms. Here, we show that POU5F1B fosters cell invasiveness by inducing plasma membrane remodeling. This ability exquisitely depends on a series of post-translational modifications. Ubiquitination of two lysine residues found exclusively in human POU5F1B results in its cytoplasmic retention, contrasting with the nuclear POU5F1. ZDHHC17-mediated S-acylation then triggers POU5F1B association with membrane nanodomains enriched in cell adhesion and signaling molecules. This is accompanied by the cell surface clustering and accelerated turnover of focal adhesion proteins, with enhanced cell invasiveness. Finally, screening for inducers of POU5F1B degradation, we found its stability to depend critically on Rho-associated protein kinases, revealing potential avenues for the treatment of POU5F1B-expressing tumors.

cancer biology↗

bioRxiv2023

Spatial proteomics in neurons at single-protein resolution

To fully understand biological processes and functions, it is necessary to reveal the molecular heterogeneity of cells and even subcellular assemblies by gaining access to the location and interaction of all biomolecules. The study of protein arrangements has seen significant advancements through super-resolution microscopy, but such methods are still far from reaching the multiplexing capacity of spatial proteomics. Here, we introduce Secondary label-based Unlimited Multiplexed DNA-PAINT (SUM-PAINT), a high-throughput imaging method capable of achieving virtually unlimited multiplexing at better than 15 nm spatial resolution. Using SUM-PAINT, we generated the most extensive multiprotein dataset to date at single-protein spatial resolution, comprising up to 30 distinct protein targets in parallel and adapted omics-inspired analysis workflows to explore these feature-rich datasets. Remarkably, by examining the multiplexed protein content of almost 900 individual synapses at single-protein resolution, we revealed the complexity of synaptic heterogeneity, ultimately leading to the discovery of a new synapse type. This work provides not only a feature-rich resource for researchers, but also an integrated data acquisition and analysis workflow for comprehensive spatial proteomics at single-protein resolution, paving the way for Localizomics.

neuroscience↗