Biology subjects

Di Fraia, D.

Publications and source records attributed to Di Fraia, D..

9 recordsLinked to original sources

bioRxiv2025

Oxidative stress causes a reversible decrease of deubiquitylases activity in old vertebrate brains

The ubiquitin-proteasome system is essential for neuronal proteostasis, and its activity declines with age. How deubiquitylating enzymes (DUBs) are affected by aging in the vertebrate brain remains unclear. Here, we profiled cysteine protease DUBs using activity-based proteomics in aging mouse and killifish brains. Despite stable protein levels, we identified a subset of DUBs that progressively lose catalytic activity with age. We demonstrated that oxidative stress impairs DUB function through thiol oxidation and that antioxidant treatment restores their activity in vitro and in vivo. Further, inhibition of DUBs in human iPSC-derived neurons significantly recapitulated ubiquitylation changes observed in aged brains, and temporal analysis in mice revealed that DUB inhibition precedes proteasome decline in the brain during aging. Together, these findings indicate a redox-sensitive subset of DUBs that undergo an age-associated decline in activity and suggest that impaired deubiquitylation is an early, yet potentially reversible, driver of proteostasis decline in the aging brain.

biochemistry↗

bioRxiv2025

The microcephaly-associated protein YIPF5 differentially regulates ER-export

YIPF5 is a small ER-membrane protein implicated in ER-Golgi transport. Mutations in YIPF5 cause MEDS2 (microcephaly with simplified gyral pattern, epilepsy, and neonatal diabetes syndrome), a fatal disorder manifesting in early childhood. We demonstrate that YIPF5 is involved in ER export of a subset of proteins, including cargoes of the ER-export receptor SURF4, with which it directly interacts. In YIPF5 knockout cells, we observe a shift in the cell surface and secretome composition, marked by reduced neuronal adhesion molecules and increased secretion of ER chaperones influencing cell migration. YIPF5 depletion enhances cell migration in a wound-healing assay and alters SURF4 localization, causing elongated ERGIC53- and Rab1-positive tubules from COPII-labeled ER exit sites. Kinetic analysis suggests that YIPF5 negatively regulates SURF4-mediated ER export. In utero knockdown of Yipf5 in embryonic mouse brains induces premature neuronal migration and abnormal neuronal morphology. These findings suggest that YIPF5 and SURF4 coordinate ER export, and disruption may underlie cortical development defects leading to microcephaly.

cell biology↗

bioRxiv2024

Cell-Type Resolved Protein Atlas of Brain Lysosomes Identifies SLC45A1-Associated Disease as a Lysosomal Disorder

Mutations in lysosomal genes cause neurodegeneration and neurological lysosomal storage disorders (LSDs). Despite their essential role in brain homeostasis, the cell-type-specific composition and function of lysosomes remain poorly understood. Here, we report a quantitative protein atlas of the lysosome from mouse neurons, astrocytes, oligodendrocytes, and microglia. We identify dozens of novel lysosomal proteins and reveal the diversity of the lysosomal composition across brain cell types. Notably, we discovered SLC45A1, mutations in which cause a monogenic neurological disease, as a neuron-specific lysosomal protein. Loss of SLC45A1 causes lysosomal dysfunction in vitro and in vivo. Mechanistically, SLC45A1 plays a dual role in lysosomal sugar transport and stabilization of V1 subunits of the V-ATPase. SLC45A1 deficiency depletes the V1 subunits, elevates lysosomal pH, and disrupts iron homeostasis causing mitochondrial dysfunction. Altogether, our work redefines SLC45A1-associated disease as a LSD and establishes a comprehensive map to study lysosome biology at cell-type resolution in the brain and its implications for neurodegeneration.

cell biology↗

bioRxiv2024

iSODA: A Comprehensive Tool for Integrative Omics Data Analysis in Single- and Multi-Omics Experiments

Omics technologies including genomics, proteomics, metabolomics, and lipidomics allow profound insights into health and disease. Thanks to plummeting costs of continuously evolving omics analytical platforms, research centers collect multi-omics data more routinely. They are, however, confronted with the lack of a versatile software solution to harmoniously analyze single-omics data and merge and interpret multi-omics data. We have developed iSODA, an interactive web-based application for the analysis of single-as well as multi-omics omics data. The software tool emphasizes intuitive, interactive visualizations designed for user-driven data exploration. Researchers can filter and normalize their datasets and access a variety of functions ranging from simple data visualization like volcano plots and PCA, to advanced functional analyses like enrichment analysis for proteomics and saturation analysis for lipidomics. For insights from integrated multi-omics, iSODA incorporates Multi-Omics Factor Analysis - MOFA, and Similarity Network Fusion - SNF. All results are presented in interactive plots with the possibility of downloading plots and associated data. The ability to adapt the imported data on-the-fly allows for tasks such as removal of outlier samples or failed features, various imputation strategies, or data normalization. The modular design allows for extensions with new analyses and plots. The software is accessible under http://isoda.online/. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/605811v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@1eb61c8org.highwire.dtl.DTLVardef@60a7feorg.highwire.dtl.DTLVardef@1b54b41org.highwire.dtl.DTLVardef@15fd1b2_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical summary for iSODA showcasing some application examples, the data import, the single-omics and multi-omics modules.

bioinformatics↗

bioRxiv2023

Remodeling of the protein ubiquitylation landscape in the aging vertebrate brain

Post-translational modifications (PTMs) regulate protein homeostasis and function. How aging affects the landscape of PTMs remains largely elusive. Here, we reveal changes in hundreds of protein ubiquitylation, acetylation, and phosphorylation sites in the aging brain of mice. We show that aging has a major impact on protein ubiquitylation and that 29% of the ubiquitylation sites are affected independently of protein abundance, indicating altered PTM stoichiometry. We found a subset of these sites to be also affected in the brain of the short-lived killifish Nothobranchius furzeri, highlighting a conserved aging phenotype. Furthermore, we estimated that over 35% of ubiquitylation changes observed in old mouse brains derive from partial proteasome inhibition, a well-established hallmark of brain aging. Our findings provide evidence of an evolutionarily conserved ubiquitylation signature of the aging brain and establish a causal link between proteasome inhibition and age-related remodeling of the ubiquitylome.

systems biology↗

bioRxiv2023

Automated workflow for BioID improves reproducibility and identification of protein-protein interactions

Proximity dependent biotinylation is an important method to study protein-protein interactions in cells, for which an expanding number of applications has been proposed. The laborious and time consuming sample processing has limited project sizes so far. Here, we introduce an automated workflow on a liquid handler to process up to 96 samples at a time. The automation does not only allow higher sample numbers to be processed in parallel, but also improves reproducibility and lowers the minimal sample input. Furthermore, we combined automated sample processing with shorter liquid chromatography gradients and data-independent acquisition to increase analysis throughput and enable reproducible protein quantitation across a large number of samples. We successfully applied this workflow to optimise the detection of proteasome substrates by proximity-dependent labelling.

biochemistry↗

bioRxiv2023

A comprehensive atlas of the aging vertebrate brain reveals signatures of progressive proteostasis dysfunction

Aging and neurodegeneration entail diverse cellular and molecular hallmarks. Here, we studied the effects of aging on the transcriptome, translatome, and multiple layers of the proteome in the brain of a short-lived killifish. We reveal that aging causes widespread reduction of proteins enriched in basic amino acids that is independent of mRNA regulation, and it is not due to impaired proteasome activity. Instead, we identify a cascade of events where aberrant translation pausing leads to reduced ribosome availability resulting in proteome remodeling independently of transcriptional regulation. Our research uncovers a vulnerable point in the aging brains biology - the biogenesis of basic DNA/RNA binding proteins. This vulnerability may represent a unifying principle that connects various aging hallmarks, encompassing genome integrity and the biosynthesis of macromolecules. One-Sentence SummaryTranslation pausing reshapes the aging brain proteome, revealing vulnerabilities in the biogenesis of nucleic-acid protein.

systems biology↗

bioRxiv2022

ProteasomeID: quantitative mapping of proteasome interactomes and substrates for in vitro and in vivo studies

Proteasomes are essential molecular machines responsible for the degradation of proteins in eukaryotic cells. Altered proteasome activity has been linked to neurodegeneration, auto-immune disorders and cancer. Despite the relevance for human disease and drug development, no method currently exists to monitor proteasome composition and interactions in vivo in animal models. To fill this gap, we developed a strategy based on tagging of proteasomes with promiscuous biotin ligases and generated a new mouse model enabling the quantification of proteasome interactions by mass spectrometry. We show that biotin ligases can be incorporated in fully assembled proteasomes without negative impact on their activity. We demonstrate the utility of our method by identifying novel proteasome-interacting proteins, charting interactomes across mouse organs, and showing that proximity-labeling enables the identification of both endogenous and small molecule-induced proteasome substrates.

biochemistry↗

bioRxiv2021

Conserved exchange of paralog proteins during neuronal differentiation

Gene duplication enables the emergence of new functions by lowering the general evolutionary pressure. Previous studies have highlighted the role of specific paralog genes during cell differentiation, e.g., in chromatin remodeling complexes. It remains unexplored whether similar mechanisms extend to other biological functions and whether the regulation of paralog genes is conserved across species. Here, we analyze the expression of paralogs across human tissues, during development and neuronal differentiation in fish, rodents and humans. While ~80% of paralog genes are co-regulated, a subset of paralogs shows divergent expression profiles, contributing to variability of protein complexes. We identify 78 substitutions of paralog pairs that occur during neuronal differentiation and are conserved across species. Among these, we highlight a substitution between the paralogs SEC23A and SEC23B subunits of the COPII complex. Altering the ratio between these two proteins via RNAi-mediated knockdown is sufficient to influence neuron differentiation. We propose that remodeling of the vesicular transport system via paralog substitutions is an evolutionary conserved mechanism enabling neuronal differentiation.

systems biology↗