Publications by authors named "Chevreux Guillaume"

Candida albicans is an opportunist pathogen responsible for a broad spectrum of infections, from superficial mycosis to the systemic disease candidiasis. C. albicans has various morphological forms, including unicellular budding yeasts, filamentous pseudohyphae and true hyphae, and the ability to switch from yeast to hyphal forms is a key survival mechanism underlying the adaptation of the pathogen to the microenvironments encountered within the host.

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  • - Ciliates use a programmed genome elimination process involving small RNAs (scnRNAs) that help remove transposable elements (TEs) from the somatic nucleus during development.
  • - scnRNAs are produced from the germline genome and transported to the maternal somatic nucleus, where scnRNAs corresponding to germline-specific sequences are selected for degradation.
  • - The study identifies Gtsf1 as necessary for the selective degradation of scnRNAs tied to retained sequences, suggesting it works alongside the Ptiwi09 protein in the somatic nucleus to regulate this elimination process through a mechanism similar to microRNA degradation in other organisms.
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Purpose: Cluster of differentiation 40 (CD40) is expressed on B-cell acute lymphoblastic leukemia (B-ALL) cases. However, the effect of CD40 activation on B-ALL cells has never been tested in vivo.

Experimental Design: The aim of our preclinical study was to investigate the therapeutic potential of a CD40 agonist in the treatment of B-ALL using patient-derived xenograft (PDX) mouse models.

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Protein mycoloylation is a recently identified unusual post-translational modification (PTM) exclusively observed in Mycobacteriales, an order of bacteria that includes several human pathogens. These bacteria possess a distinctive outer membrane, known as the mycomembrane, composed of very long-chain fatty acids called mycolic acids. It has been demonstrated that a few mycomembrane proteins undergo covalent modification with mycolic acids in the model organism through the action of mycoloyltransferase MytC.

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  • Understanding RNA targeting to membraneless organelles like P-bodies (PBs) is crucial for revealing their functions in cells.
  • This study shows that PBs in HEK293 cells undergo significant changes in RNA content throughout the cell cycle, with different mRNA localization patterns appearing at various stages (G1, S, G2).
  • The findings suggest that PBs actively sort mRNAs based on their translation status and characteristics, implying that they play a more dynamic role than merely housing excess untranslated mRNAs.
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Exome sequencing has enabled the identification of causative genes of monogenic forms of autism, amongst them, in 2016, CSNK2A1, the gene encoding the catalytic subunit of the kinase CK2, linking this kinase to Okur-Chung Neurodevelopmental Syndrome (OCNDS), a newly described neurodevelopmental condition with many symptoms resembling those of autism spectrum disorder. Thus far, no preclinical model of this condition exists. Here we describe a knock-in mouse model that harbors the K198R mutation in the activation segment of the α subunit of CK2.

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Crucial for skin homeostasis, synthesis and degradation of extracellular matrix components are orchestrated by dermal fibroblasts. During aging, alterations of component expression, such as collagens and enzymes, lead to reduction of the mechanical cutaneous tension and defects of skin wound healing. The aim of this study was to better understand the molecular alterations underwent by fibroblasts during aging by comparing secretomic and proteomic signatures of fibroblasts from young (<35years) and aged (>55years) skin donors, in quiescence or TGF-stimulated conditions, using HLPC/MS.

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  • Some germs called Theileria parasites can live inside cow's white blood cells and make them sick.
  • They have special tricks to survive inside these cells, like stealing proteins from the cows so they won’t be thrown out.
  • Scientists found a new medicine that helps the cows' cells fight back by making them clear out the parasites more effectively.
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Exit from mitosis is brought about by dramatic changes in the phosphoproteome landscape. A drop in Cyclin-dependent kinase (Cdk) activity, the master regulatory kinase, and activation of counteracting phosphatases such as Cdc14 in budding yeast, results in ordered substrate dephosphorylation, allowing entry into a new cell cycle and replication licensing. In meiosis however, two cell divisions have to be executed without intermediate DNA replication, implying that global phosphorylation and dephosphorylation have to be adapted to the challenges of meiosis.

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  • - The study investigates the complex clinical and metabolic effects associated with inborn errors of cobalamin metabolism, particularly focusing on cblC and epi-cblC cases, to better understand their variability and underlying mechanisms.
  • - Researchers utilized metabolomic, genomic, proteomic, and post-translational modification analyses on fibroblasts from cblC and cblG patient cases, revealing notable disruptions in metabolic pathways such as the urea cycle and mitochondrial energy production.
  • - Findings highlight significant changes in enzyme expression and activity, which could explain clinical symptoms like neurological issues and developmental delays in patients; further research is needed to confirm these connections.
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Proline dehydrogenase (ProDH) and pyrroline-5-carboxylate (P5C) dehydrogenase (P5CDH) catalyse the oxidation of proline into glutamate via the intermediates P5C and glutamate-semialdehyde (GSA), which spontaneously interconvert. P5C and GSA are also intermediates in the production of glutamate from ornithine and α-ketoglutarate catalysed by ornithine δ-aminotransferase (OAT). ProDH and P5CDH form a fused bifunctional PutA enzyme in Gram-negative bacteria and are associated in a bifunctional substrate-channelling complex in Thermus thermophilus; however, the physical proximity of ProDH and P5CDH in eukaryotes has not been described.

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N-terminal ends of polypeptides are critical for the selective co-translational recruitment of N-terminal modification enzymes. However, it is unknown whether specific N-terminal signatures differentially regulate protein fate according to their cellular functions. In this work, we developed an in-silico approach to detect functional preferences in cellular N-terminomes, and identified in S.

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Cytoplasmic linker-associated proteins (CLASPs) form a conserved family of microtubule-associated proteins (MAPs) that maintain microtubules in a growing state by promoting rescue while suppressing catastrophe. CLASP function involves an ordered array of tumor overexpressed gene (TOG) domains and binding to multiple protein partners via a conserved C-terminal domain (CTD). In migrating cells, CLASPs concentrate at the cortex near focal adhesions as part of cortical microtubule stabilization complexes (CMSCs), via binding of their CTD to the focal adhesion protein PHLDB2/LL5β.

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The nuclear envelope, which protects and organizes the genome, is dismantled during mitosis. In the zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the maternal and paternal genomes. Nuclear pore complex (NPC) disassembly is a decisive step of NEBD, essential for nuclear permeabilization.

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Background: Mirror movements are involuntary movements of one hand that mirror intentional movements of the other hand. Congenital mirror movements (CMM) is a rare genetic disorder with autosomal dominant inheritance, in which mirror movements are the main neurological manifestation. CMM is associated with an abnormal decussation of the corticospinal tract, a major motor tract for voluntary movements.

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Unlabelled: The nuclear envelope, which protects and organizes the interphase genome, is dismantled during mitosis. In the zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the parental genomes. During NEBD, Nuclear Pore Complex (NPC) disassembly is critical for rupturing the nuclear permeability barrier and removing the NPCs from the membranes near the centrosomes and between the juxtaposed pronuclei.

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The simple light isotope metabolic-labeling technique relies on the biosynthesis of amino acids from U-[C]-labeled molecules provided as the sole carbon source. The incorporation of the resulting U-[C]-amino acids into proteins presents several key advantages for mass-spectrometry-based proteomics analysis, as it results in more intense monoisotopic ions, with a better signal-to-noise ratio in bottom-up analysis. In our initial studies, we developed the simple light isotope metabolic (SLIM)-labeling strategy using prototrophic eukaryotic microorganisms, the yeasts and , as well as strains with genetic markers that lead to amino-acid auxotrophy.

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Viruses must overcome the interferon-mediated antiviral response to replicate and propagate into their host. Rabies virus (RABV) phosphoprotein P is known to inhibit interferon induction. Here, using a global mass spectrometry approach, we show that RABV P binds to TBK1, a kinase located at the crossroads of many interferon induction pathways, resulting in innate immunity inhibition.

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Candida albicans is an opportunist pathogen responsible for a large spectrum of infections, from superficial mycosis to systemic diseases known as candidiasis. During infection in vivo, Candida albicans must adapt to host microenvironments and this adaptive response is crucial for the survival of this organism, as it facilitates the effective assimilation of alternative carbon sources others than glucose. We performed a global proteomic analysis on the global changes in protein abundance in response to changes in micronutrient levels, and, in parallel, explored changes in the intracellular redox and metabolic status of the cells.

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In top-down proteomics experiments, intact protein ions are subjected to gas-phase fragmentation for MS analysis without prior digestion. This approach is used to characterize post-translational modifications and clipped forms of proteins, avoids several "inference" problems associated with bottom-up proteomics, and is well suited to the study of proteoforms. In the past decade, top-down proteomics has progressed rapidly, taking advantage of MS instrumentation improvements and the efforts of pioneering groups working to improve sample handling and data processing.

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Orthohantaviruses are rodent-borne emerging viruses that may cause severe diseases in humans but no apparent pathology in their small mammal reservoirs. However, the mechanisms leading to tolerance or pathogenicity in humans and persistence in rodent reservoirs are poorly understood, as is the manner in which they spread within and between organisms. Here, we used a range of cellular and molecular approaches to investigate the interactions of three different orthohantaviruses-Puumala virus (PUUV), responsible for a mild to moderate form of hemorrhagic fever with renal syndrome in humans, Tula virus (TULV) with low pathogenicity, and non-pathogenic Prospect Hill virus (PHV)-with human and rodent host cell lines.

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  • Cilia assembly in metazoans involves crucial steps such as centriole maturation, migration to the cell surface, and docking with the plasma membrane; mutations affecting these processes are linked to severe ciliopathies.* -
  • The study uses Paramecium as a model organism to discover that proteins CEP90, FOPNL, and OFD1 are essential for ciliogenesis and are conserved across different species.* -
  • The research reveals that these proteins localize at the distal ends of centrioles/basal bodies and require an additional component, Moonraker (MNR), for proper recruitment and assembly in mammalian cells.*
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  • Protein tyrosine phosphatase 1B (PTP1B) is crucial for regulating signalling pathways, especially the EGFR pathway, and its biological significance is underscored by studies showing mutations linked to metabolic and cancer-related changes.
  • Cisplatin, a common chemotherapy drug, traditionally works by damaging DNA, but recent evidence suggests it also affects cell signalling by interacting with specific proteins, including PTP1B.
  • Research indicates that cisplatin irreversibly inhibits PTP1B by binding to its catalytic cysteine, leading to increased tyrosine phosphorylation of EGFR, thus revealing new insights into how cisplatin affects cellular processes beyond just DNA damage.
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Simple light isotope metabolic labeling (bSLIM) is an innovative method to accurately quantify differences in protein abundance at the proteome level in standard bottom-up experiments. The quantification process requires computation of the ratio of intensity of several isotopologs in the isotopic cluster of every identified peptide. Thus, appropriate bioinformatic workflows are required to extract the signals from the instrument files and calculate the required ratio to infer peptide/protein abundance.

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Polycomb repressive complex 2 (PRC2) maintains transcriptionally silent genes in a repressed state via deposition of histone H3K27-trimethyl (me3) marks. PRC2 has also been implicated in silencing transposable elements (TEs), yet how PRC2 is targeted to TEs remains unclear. To address this question, we identified proteins that physically interact with the Paramecium enhancer-of-zeste Ezl1 enzyme, which catalyzes H3K9me3 and H3K27me3 deposition at TEs.

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