Biology subjects

Bevers, S.

Publications and source records attributed to Bevers, S..

11 recordsLinked to original sources

bioRxiv2026

Mitotic kinase regulation of DNA replication forks

While DNA replication forks initiate in S phase, they do not necessarily complete and terminate prior to cell entry into mitosis. How mitotic proteins regulate leftover replication forks is not well-understood. Using reconstituted DNA replication forks with purified proteins, we show that the budding yeast mitotic kinases Clb2-CDK (M-CDK) and Cdc5 (Plk1 homolog) phosphorylate and regulate several replication elongation proteins. Mrc1 phosphorylation by both kinases results in slower replication, and Pol phosphorylation by M-CDK results in less lagging strand initiation. We further show that a phospho-resistant mutant of Pol bypasses M-CDK inhibition of Pol activity in reconstituted replication reactions. Yeast cells expressing the phospho-resistant mutant exhibit faster cell cycle progression revealing a potential negative feedback mechanism between DNA replication forks and mitotic progression.

molecular biology↗

bioRxiv2026

A population-scale red blood cell proteome reveals genetically encoded aging clocks predictive of hemolysis and blood donor activity

As the most abundant human cell and the foundation of transfusion medicine, red blood cells (RBCs) offer a unique readout of systemic health, yet they have never been characterized at population scale. We generated a proteome atlas of 13,091 blood donors with multi-omics longitudinal phenotyping, characterizing the influence of demographics and genetic variation on the reproducibility of RBC proteomes across donations. Elastic-net aging clocks captured biological aging with high accuracy and uncovered genetic regulators of {Delta}Age at FN1, C4/IKZF1, CRAT, PFAS, TRIM58. Across independent cohorts, {Delta}Age was accelerated in G6PD deficiency, sickle cell trait/disease, and iron deficiency, reversed by iron repletion, and slowed in high-frequency donors, linking molecular aging to brain iron/myelin and cognitive performance. Molecular aging signatures predicted storage, osmotic, and oxidative hemolysis, hemoglobin increments after transfusion, and long-term donor activity over 12-years. These results establish RBC proteomics as a scalable biomarker of aging, donor healthspan, and transfusion outcomes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/710284v1_ufig1.gif" ALT="Figure 1"> View larger version (96K): org.highwire.dtl.DTLVardef@15bd46eorg.highwire.dtl.DTLVardef@1d7c107org.highwire.dtl.DTLVardef@1c1d870org.highwire.dtl.DTLVardef@168dc6f_HPS_FORMAT_FIGEXP M_FIG Dzieciatkowska et al. generate the first population-scale atlas of the RBC proteome across 13,000 donors and develop proteomic and metabolomic aging clocks that quantify biological age. Molecular {Delta}Age is reproducible across donations, genetically encoded and accelerated in G6PD deficiency, sickle cell trait/disease, and iron deficiency - yet reset by iron repletion, tracking with cognitive function and brain iron/myelin. RBC aging clocks predict hemolytic fragility, transfusion efficacy, and donor activity 12 years later. C_FIG HighlightsO_LIRBC proteome atlas of 13,091 donors reveals demographic and genetic programs C_LIO_LIGenetically encoded RBC aging clocks identify regulators of molecular {Delta}age C_LIO_LIMolecular aging features predict hemolysis and transfusion response across cohorts C_LIO_LIRBC molecular age forecasts long-term donor activity over a 12-year follow-up C_LI

biochemistry↗

bioRxiv2026

Longitudinal tumor ecosystem mapping defines glioblastoma treatment trajectories

Glioblastoma remains an invariably recurring and lethal brain tumor shaped by complex interactions between malignant and microenvironmental cells. How these interactions evolve under first-line standard-of-care (SOC) therapy remains unclear. We performed spatial single-cell profiling of 671 paired newly diagnosed and recurrent glioblastoma samples from 96 patients to map tumor-ecosystem evolution and its clinical relevance. We delineated five distinct patient subgroups, each characterized by unique ecosystem trajectories that correlated with clinical outcome. Patients whose tumors transitioned into oligodendrocyte-progenitor-like niches with enhanced vascular integrity, oxygenation and an IL10/CCL/MHCII immunomodulatory environment experienced improved clinical prognosis. In contrast, progression towards hypoxic mesenchymal/astrocyte-like niches dominated by strong LGALS1/SPP1/TGF{beta} immunosuppression predicted poor outcome. Furthermore, a subgroup of early-relapsing patients on SOC therapy that was characterized by a depletion of an antigen-presenting myeloid-cell-rich niche, exhibited diminished responsiveness to second-line lomustine therapy. Overall, mapping evolutions in glioblastoma ecosystems offers a novel framework for prognostic stratification and therapeutic guidance.

cancer biology↗

bioRxiv2025

Deep Red Blood Cell Proteome Defines the Band 3 N-Terminus Interactome as a Regulator of Hypoxic Adaptation via BLVRB-Dependent S-Nitroso Transfer

Red blood cells (RBCs) have long been regarded as passive oxygen carriers, yet growing evidence reveals a complex, dynamic proteome independent of de novo gene expression. Here, we define the erythrocyte as an oxygen-responsive system organized around a Band 3 (SLC4A1)-centered metabolon. Using deep proteomics of ultra-pure RBCs and cross-linking interactomics, we identify biliverdin reductase B (BLVRB) as a previously unrecognized Band 3 interactor that binds the N-terminal cytosolic domain under normoxia and dissociates under hypoxia, when band 3-deoxyhemoglobin interactions increase threefold. This reversible interaction forms an oxygen-sensitive switch coupling structural, redox, and metabolic remodeling. In humanized mice, truncation of the Band 3 N-terminus disrupted glycolytic activation, reduced 2,3-bisphosphoglycerate synthesis, and impaired exercise tolerance despite preserved cardiopulmonary function, establishing the physiological relevance of this module. Population-scale proteome quantitative trait locus (pQTL) analyses revealed coordinated variation of SLC4A1 and BLVRB abundance but minimal association of biliverdin levels with BLVRB genotype, suggesting alternative functions beyond heme catabolism. Mechanistically, BLVRB Cys109 acts as a nitric oxide (NO) relay, trans-nitrosating glycolytic enzymes such as GAPDH at active site Cys152, transiently inhibiting glycolysis. This S-nitrosation-mediated feedback mirrors conserved mechanisms in plants, where GAPDH-SNO redirects carbon flow toward the Calvin-Benson cycle under nitrosative stress, revealing an evolutionary convergence in gas-responsive metabolic control. Collectively, our findings define a Band 3-BLVRB-hemoglobin axis that links oxygen sensing, NO signaling, and redox homeostasis, providing a unifying model for how an anucleate cell achieves environmental adaptability through reversible protein-protein interactions and post-translational chemistry. Graphic abstractIssaian et al. define the most comprehensive proteome of ultra-pure human red blood cells (3,775 proteins) and map the O2-dependent interactome, revealing a Band 3-BLVRB-hemoglobin module that links oxygen sensing to metabolic remodeling via reversible inhibitory S-nitrosation of GAPDH C152. In plants this redirects carbon toward photosynthesis, illustrating a conserved NO-dependent metabolic reprogramming mechanism across oxygen-regulated systems. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/691178v1_ufig1.gif" ALT="Figure 1"> View larger version (89K): org.highwire.dtl.DTLVardef@122468org.highwire.dtl.DTLVardef@114428dorg.highwire.dtl.DTLVardef@11d40c4org.highwire.dtl.DTLVardef@1870fb7_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIDeep proteomics defines a complete, contamination-free RBC proteome (3,775 proteins) C_LIO_LICross-linking proteomics maps an oxygen-sensitive Band 3-centered interactome C_LIO_LIO2-dependent BLVRB-Band 3 binding regulates metabolism via S-nitrosation of GAPDH C_LIO_LIBand 3 N-terminus is required for hypoxic remodeling and exercise tolerance in vivo C_LI

biochemistry↗

bioRxiv2025

Genetic variation of human G6PD impacts Red Blood Cell transfusion efficacy

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common human enzymopathy, affects 6% of the global population, yet its impact on blood storage and transfusion efficacy remains undefined. We integrated genome-metabolome-proteome analyses of 13,091 blood donors (362 G6PD SNPs), validated in a recalled cohort (n=643), linked donor-recipient databases, humanized mouse models (canonical, African A- [V68M+N126D], Mediterranean [S188F]), and a prospective sickle cell disease study. Common G6PD variants reduced protein abundance, reprogrammed redox metabolism, and increased storage hemolysis. In mice, G6PD-deficient RBCs showed lower post-transfusion recovery, higher oxidative stress, and impaired renal oxygenation. Clinically, recipients of G6PD-deficient units exhibited smaller hemoglobin increments and reduced RBC L{superscript 1}Cr-survival (-8% at 24 h; -12% at 4 weeks). Structural studies revealed kinetic fragility for A- and thermodynamic fragility for Med-, linking genotype to protein instability and transfusion outcome. These findings identify donor G6PD genotype as a determinant of transfusion efficacy, supporting genotype-aware inventory-management strategies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/689741v1_ufig1.gif" ALT="Figure 1"> View larger version (76K): org.highwire.dtl.DTLVardef@1897489org.highwire.dtl.DTLVardef@1420587org.highwire.dtl.DTLVardef@178e8ddorg.highwire.dtl.DTLVardef@1003b44_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2025

U1 snRNP and RNA polymerase II interaction is predominantly mediated by Prp40 rather than U1-70K in yeast

Transcription and splicing are coupled both temporally and physically. A previous cryo-EM structure of the human U1 snRNP and RNA polymerase pol II complex has shown that U1 snRNP uses predominantly the RRM domain of U1-70K to directly interact with the RPB2 subunit of pol II. However, residues on U1-70K involved in the interaction with pol II are not conserved in yeast U1-70K, raising the question whether yeast U1 snRNP interacts with pol II in a similar manner. We found that yeast pol II associates with both U1 and U2 snRNPs, but U1-70K makes a minimal contribution to U1 snRNPs interaction with pol II. On the other hand, multiple domains of yeast Prp40 interact with pol II and the removal of the C-terminal domain (CTD) of pol II does not affect this interaction. Although yeast Prp40 is stably associated with U1 snRNP, its human homologs, PRPF40a and PRPF40b, are alternative splicing factors that are not integral components of U1 snRNP. This shift of function of Prp40 homologs may have led to the evolution of U1-70K to be the main interactor with pol II in the human system.

biochemistry↗

bioRxiv2025

Caffeine Impairs Red Blood Cell Storage Quality by Dual Inhibition of ADORA2b Signaling and G6PD Activity

Caffeine is the most widely consumed psychoactive substance globally, yet its peripheral physiological effects remain incompletely understood. Leveraging comprehensive data from 13,091 blood donors in the REDS RBC-Omics study, we identify caffeine as a significant modulator of red blood cell (RBC) storage quality and transfusion outcomes. Elevated caffeine levels were reproducible across multiple donations from 643 recalled donors, selected based on their extremes in hemolytic propensity. Both in the screening and recalled cohorts, higher caffeine levels were associated with disrupted RBC metabolism, characterized by reduced glycolysis, depletion of adenylate pools or 2,3-bisphosphoglycerate, and increased markers of oxidative stress and osmotic fragility, including kynurenine accumulation. These observations were recapitulated in plasma and RBCs of eight volunteers upon consumption of a cup of coffee independently of brewing method (Chemex vs espresso). Clinically, elevated caffeine correlated with increased hemolysis and lower post-transfusion hemoglobin increments, especially pronounced in recipients transfused with RBCs from donors carrying common polymorphisms in the ADORA2b gene, a key regulator of RBC metabolism in hypoxia. These human findings were mechanistically validated using a murine model deficient in ADORA2b, which demonstrated impaired glycolytic flux, compromised antioxidant defenses - including caffeine-dependent direct inhibition of recombinantly-expressed glucose 6-phosphate dehydrogenase, and decreased transfusion efficacy (lower hemoglobin increments, higher bilirubin post-transfusion), effects further exacerbated by caffeine exposure during storage. Our study positions caffeine consumption as a modifiable factor in blood transfusion practice, advocating for precision strategies that integrate genetic and exposome factors, and identifies metabolic interventions to enhance blood quality and clinical outcomes. One sentence summaryCaffeine consumption and genetic variants in the ADORA2b receptor synergistically impair red blood cell metabolism and transfusion efficacy, revealing a modifiable exposome-gene interaction for precision transfusion medicine.

biochemistry↗

bioRxiv2022

Alpha-1-antitrypsin binds to the glucocorticoid receptor with biological significance in macrophages

Alpha-1-antitrypsin (AAT), a serine protease inhibitor produced mainly by the liver, is the third most abundant protein in plasma. While a canonical receptor for AAT has not been identified, AAT can be internalized into the cytoplasm and is known to affect gene regulation. Since AAT has significant anti-inflammatory properties affecting many cell types including macrophages, we examined whether AAT binds the cytoplasmic glucocorticoid receptor (GR) in macrophages. We report the novel finding that AAT binds to GR in macrophages using several approaches, including co-immunoprecipitation, mass spectrometry, microscale thermophoresis, and molecular modeling. The mass spectrometry data are available via ProteomeXchange with identifier PXD030989. We further demonstrate that AAT induction of angiopoietin-like 4 protein and AAT inhibition of lipopolysaccharide-induced nuclear factor-kappa B activation and interleukin-8 production are mediated, in part, through AAT-GR interaction. Furthermore, this interaction contributes to a host-protective role against mycobacteria in macrophages. The interaction of AAT and GR described in this study identifies a mechanism for the antiinflammatory and host-defense properties of AAT.

immunology↗

bioRxiv2022

Heparins enhance C1 esterase inhibitor activity: a promising remedy for acute hereditary angioedema

RationaleHereditary angioedema (HAE) is a potentially life-threatening illness most commonly due to deficiency or dysfunction of C1-esterase inhibitor (C1-INH). While specific treatments are available to thwart acute exacerbations, they are extremely costly and some can be associated with rare but serious side effects. The heparins are long known to augment C1-INH activity and case reports / series have documented their efficacy in treating HAE. Objectiveto determine if unfractionated heparin and two low-molecular weight heparins (enoxaparin and nadroparin) can augment C1-INH activity ex vivo in the sera of patients with HAE and in an in vitro biochemical assay. MethodsC1-INH activity in the absence or presence of the heparin formulations were analyzed by two different methods. To measure C1-INH activity ex vivo, a commercially available assay was utilized with patient sera, excess amounts of C1s, and a substrate of C1s which, upon cleavage by C1s, produces a chromogenic product. To determine biochemically the C1-INH activity in vitro, a pharmacologic grade C1-INH, recombinant C1s (C1s-CCP12SP), and a peptide substrate of C1s were employed. Microscale thermophoresis was used to determine whether C1-INH binds to heparin. Main resultsin patient sera, nadroparin was superior to enoxaparin and unfractionated heparin in augmenting C1-INH activity, followed by enoxaparin and then unfractionated heparin. In the in vitro biochemical assay, all three heparins augmented C1-INH-C1s binding linearly in a dose-dependent fashion. Microscale thermophoresis assay demonstrated that nadroparin binds to C1-INH, providing a mechanism by which heparin facilitates the interaction between C1-INH and the proteases known to produce bradykinin, the mediator of HAE. Conclusionlow-molecular weight heparin augments C1-INH activity and should be studied as a potential treatment for acute HAE.

pharmacology and toxicology↗

bioRxiv2021

Binding of Monomeric and Polymeric Alzheimers Aβ peptides to Exosomes

Exosomes are secreted by every cell in our body under both physiological and pathological conditions. They travel in the blood, CSF, and all studied biofluids. Their biological roles have been reported to include delivery of important physiological cargo between organs and cells, clearance of toxic proteins; maintenance of cellular stasis, and the propagation of disease pathology. In the case of Alzheimers disease (AD) exosomes have been shown to carry pathological proteins such as amyloid, yet the specificity of this association of amyloid and exosomes is unclear. To address this deficiency, we utilized Isothermal Titration Calorimetry (ITC) to measure the binding of amyloid to exosomes. Here we report that A{beta}40 and A{beta}42 bind to exosomes in a saturable and endothermic manner, a phenomenon not observed with the scrambled versions of either peptide. This points to this interaction being more specific than previously understood, and to amyloid associated with exosomes as an important pool of this peptide in the plasma.

neuroscience↗

bioRxiv2021

Towards more accurate preclinical glioblastoma modelling: reverse translation of clinical standard of care in a glioblastoma mouse model.

IntroductionContrarily to clinical trials, where glioblastoma (GBM) patients are usually heavily pre-treated (surgery, radiotherapy (RT) and temozolomide (TMZ)) before receiving the experimental therapies, in preclinical GBM studies experimental treatments have mostly been administered as monotherapy or combined with a very limited part of the clinical standard of care. This discrepancy can explain the failed clinical translation of preclinically successful treatments. This study is aimed at evaluating the feasibility and survival impact of the clinical standard of care in glioma-bearing mice. Methods. Neurospheres CT-2A tumor-bearing mice were treated with fluorescence-guided tumor resection, focal RT and oral TMZ. ResultsThe implementation of postoperative intensive care treatment reduced surgical mortality by approximately 50% and increased experimental cost-effectiveness. Partial and total tumor resection significantly prolonged survival, the latter showing the strongest effect. Mice treated with surgery combined with RT or with RT and TMZ survived significantly longer than untreated controls. ConclusionsImplementing the current GBM clinical standard of care in preclinical research is feasible and it leads to results in line with those obtained in patients. Systematic preclinical evaluation of the efficacy of experimental therapies in combination with standard of care treatments could improve the translational impact of next generation GBM animal studies.

neuroscience↗