Biology subjects

Dzwolak, W.

Publications and source records attributed to Dzwolak, W..

3 recordsLinked to original sources

bioRxiv2025

Protein-Independent Liquid - Liquid Phase Separation of Adenosine Triphosphate under Crowded Conditions

Adenosine triphosphate (ATP), a common constituent of protein-rich biomolecular condensates, itself undergoes liquid-liquid phase separation (LLPS) even in the absence of polypeptides. Using polyethylene glycol as macromolecular crowding agent, we observed robust ATP droplet formation at pH 2-11. Moderate NaCl and lower temperatures promote LLPS by lowering critical ATP and crowder concentrations. Very high salt reverses this trend through anomalous underscreening, but ATP droplets still survive in hypersaline environments. Most importantly, physiological millimolar ATP concentrations are sufficient for phase separation in the presence of millimolar Mg2+ and crowders, mimicking intracellular conditions. pH tunes intermolecular interactions, evidenced by inversion of the adenosine circular dichroism Cotton effect. These results reveal intrinsic, protein-independent LLPS of ATP with potential roles in cellular compartmentalization and pathological phase transitions.

biophysics↗

bioRxiv2025

Liquid-Liquid Phase Separation-mediated formation of amyloid fibrils from DcpS scavenger enzymes.

Decapping Scavenger (DcpS) enzyme was initially identified by its ability to hydrolyze the cap structure resulting from mRNA decay. Human DcpS is an established target for acute myeloid leukemia (AML) and hepatic metastasis. Recently, the protein has been linked to neuronal development regulation and implicated in certain developmental neurological disorders. Here we demonstrate for the first time that DcpS undergoes misfolding in vitro, leading to the formation of amyloid-like fibrils. Fibrillization was observed for human and nematode (C. elegans) DcpS using transmission electron microscope (TEM) imaging, Thioflavin T (ThT) fluorescence assay, Fourier-transform infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy, differential scanning fluorimetry (DSF), and dynamic light scattering (DLS). Additionally, the DcpSINS15 insertional mutant linked to the Al-Raquad syndrome, exhibited accelerated fibril aggregation kinetics compared to the wild type protein. Moreover, we show that the DcpS species investigated in this study undergo liquid-liquid phase separation (LLPS) prior to amyloid-formation. We propose that the LLPS phase transition underlies the intricate kinetics (e.g. lack of a clearly-resolved lag phase) of the misfolding process. As the physiological implications of the here-reported propensity of DcpS to lose its biological function through the coupled LLPS-fibrillization transition remain to be elucidated, this work lays the groundwork for further studies on this phenomenon.

molecular biology↗

bioRxiv2020

The hunt for ancient prions: Archaeal prion-like domains form amyloids and substitute for yeast prion domains

Prions are proteins capable of acquiring an alternate conformation that can then induce additional copies to adopt this same alternate conformation. Although initially discovered in relation to mammalian disease, subsequent studies have revealed the presence of prions in Bacteria and Viruses, suggesting an ancient evolutionary origin. Here we explore whether prions exist in Archaea - the last domain of life left unexplored with regard to prions. After searching for potential prion-forming protein sequences computationally, we tested candidates in vitro and in organisms from the two other domains of life: Escherichia coli and Saccharomyces cerevisiae. Out of the 16 candidate prion-forming domains tested, 8 bound to amyloid-specific dye, and six acted as protein-based elements of information transfer, driving non-Mendelian patterns of inheritance. We additionally identified short peptides from archaeal prion candidates that can form amyloid fibrils independently. Candidates that tested positively in our assays had significantly higher tyrosine and phenylalanine content than candidates that tested negatively, suggesting that the presence of these amino acids may help distinguish functional prion domains from nonfunctional ones. Our data establish the presence of amyloid-forming prion-like domains in Archaea. Their discovery in all three domains of life further suggests the possibility that they were present at the time of the last universal common ancestor (LUCA). Significance StatementThis work establishes that amyloid-forming, prion-like domains exist in Archaea and are capable of vertically transmitting their prion phenotype - allowing them to function as protein-based elements of inheritance. These observations, coupled with prior discoveries in Eukarya and Bacteria, suggest that prion-based self-assembly was likely present in lifes last universal common ancestor (LUCA), and therefore may be one of the most ancient epigenetic mechanisms.

evolutionary biology↗