The activation of PLK1 in late G2 is critical for mitotic entry, requiring its phosphorylation by Aurora-A, facilitated by the intrinsically disordered protein Bora. The structural basis of this mechanism has remained un...The activation of PLK1 in late G2 is critical for mitotic entry, requiring its phosphorylation by Aurora-A, facilitated by the intrinsically disordered protein Bora. The structural basis of this mechanism has remained unresolved. Here, we present models of the Aurora-A/Bora complex and the Aurora-A/Bora/PLK1 complex, validated with site-specific mutagenesis, biochemical assays and NMR spectroscopy. Bora wraps around the N-lobe of Aurora-A, occupying the pockets used by its other activators. A CDK1 phosphorylation site on Bora (Ser112) mimics the structural role of Aurora-A activation loop phosphorylation within a TPX2-like binding motif. In the ternary complex, Bora bridges the two kinases, orienting the activation loop of PLK1 towards the active site of Aurora-A. Bora residues 56-66 form a critical interface with a conserved pocket on the PLK1 C-helix that is analogous to the TPX2-binding Y-pocket of Aurora-A. Aurora-A phosphorylation of Bora Ser59 creates an additional interaction that increases the efficiency of PLK1 phosphorylation. These findings deepen our understanding of Aurora-A regulation by its disordered binding partners and establish a mechanistic framework for Bora-dependent activation of PLK1.
Disrupted proteostasis causes various degenerative diseases, and organelle homeostasis is therefore maintained by elaborate mechanisms. Endoplasmic reticulum (ER) stress-induced preemptive quality control (ERpQC) counter...Disrupted proteostasis causes various degenerative diseases, and organelle homeostasis is therefore maintained by elaborate mechanisms. Endoplasmic reticulum (ER) stress-induced preemptive quality control (ERpQC) counteracts stress by reducing ER load through inhibiting the translocation of newly synthesized proteins into the ER for their rapid degradation in the cytoplasm. Here, we show that Sec61β, a translocon component, prevents the overproduction of ERpQC substrates, allowing for their efficient degradation by the proteasome. Sec61β inhibits the binding of translation initiation factor eIF4E to the mRNA 5' cap structure by recruiting E3 ligase ARIH1 and eIF4E-homologous protein 4EHP, resulting in selective translational repression of ERpQC substrates. Sec61β deficiency causes overproduction of ERpQC substrates and reduces proteasome activity, leading to cytoplasmic aggresome formation. We also show that Sec61β deficiency causes motor dysfunction in zebrafish, which is restored by exogenous ARIH1 expression. Collectively, translational repression of ERpQC substrates by the Sec61β-ARIH1 complex contributes to maintain ER and cytoplasmic proteostasis.
Haematopoietic stem and progenitor cells (HSPCs) maintain haematopoiesis throughout life. Their formation occurs early in embryonic development and is regulated by many intrinsic and extrinsic factors that delicately bal...Haematopoietic stem and progenitor cells (HSPCs) maintain haematopoiesis throughout life. Their formation occurs early in embryonic development and is regulated by many intrinsic and extrinsic factors that delicately balance the need to maintain a vascular network with the need to generate HSPCs de novo. Most extrinsic factors such as BMP and Notch act instructively in haemogenic endothelial cells to induce HSPC fates. A new study by Eberlein et al (2025) identifies a key role for Apelin signalling acting indirectly by limiting the number of arterial endothelial cells that become haemogenic, independently of Notch, BMP or Wnt signalling (Eberlein et al, 2025). Arterial endothelial cells that do not respond to Apelin more frequently convert to the haemogenic endothelial cell fate, giving rise to higher numbers of haematopoietic stem and progenitor cells in the embryo that persist into adulthood. This work highlights a critical temporal window where Apelin functions as a rheostat, balancing angiogenesis, vascular maintenance and haematopoiesis.
Mechanistic target of rapamycin complex 1 (mTORC1) integrates signals from nutrients, growth factors, and cellular stress to regulate biosynthesis and maintain homeostasis. Dysregulated mTORC1 disrupts stem cell homeosta...Mechanistic target of rapamycin complex 1 (mTORC1) integrates signals from nutrients, growth factors, and cellular stress to regulate biosynthesis and maintain homeostasis. Dysregulated mTORC1 disrupts stem cell homeostasis and impairs cell fate transitions in vivo and in vitro. Previous studies have shown that mTORC1 hyperactivation promotes nuclear translocation of TFE3, blocking pluripotency exit in both mouse and human naïve embryonic stem cells. Similarly, our earlier work has demonstrated that sustained mTORC1 activation impedes somatic cell reprogramming via the transcriptional coactivator PGC1α. This raises the question of how mTORC1 coordinates gene transcription across distinct transitions in pluripotent cells. Here, we show that TFE3 mediates the transcriptional blockade induced by mTORC1 hyperactivation during reprogramming. Notably, during both pluripotency exit and reprogramming, TFE3 recruits the NuRD corepressor complex to repress genes essential for cell fate transitions. These findings uncover a shared mechanism by which mTORC1 and TFE3 regulate stem cell identity, highlighting the dual regulatory role of TFE3 and its potential implications in development, aging, and tumorigenesis.
Mitophagy maintains mitochondrial homeostasis through the selective degradation of damaged or excess mitochondria. Recently, we identified mitofissin/Atg44, a mitochondrial intermembrane space-resident fission factor, wh...Mitophagy maintains mitochondrial homeostasis through the selective degradation of damaged or excess mitochondria. Recently, we identified mitofissin/Atg44, a mitochondrial intermembrane space-resident fission factor, which directly acts on lipid membranes and drives mitochondrial fission required for mitophagy in yeast. However, it remains unclear whether mitofissin is sufficient for mitophagy-associated mitochondrial fission and whether other factors act from outside mitochondria. Here, we identify a mitochondrial outer membrane-resident mitofissin-like microprotein required for mitophagy, and we name it mitofissin 2/Mfi2 based on the following results. Overexpression of an N-terminal Atg44-like region of Mfi2 induces mitochondrial fragmentation and partially restores mitophagy in atg44Δ cells. Mfi2 binds to lipid membranes and mediates membrane fission in a cardiolipin-dependent manner in vitro, demonstrating its intrinsic mitofissin activity. Coarse-grained molecular dynamics simulations further support the stable interaction of Mfi2 with cardiolipin-containing bilayers. Genetic analyses reveal that Mfi2 and the dynamin-related protein Dnm1 independently facilitate mitochondrial fission during mitophagy. Thus, Atg44 and Mfi2, two mitofissins with distinct localizations, are required for mitophagy-associated mitochondrial fission.
Functional traits shape ecological niches, yet the interplay between nanoscale structural modifications, sexual dimorphism, and habitat range remains poorly understood. In fireflies, cuticular nanostructures that enhance...Functional traits shape ecological niches, yet the interplay between nanoscale structural modifications, sexual dimorphism, and habitat range remains poorly understood. In fireflies, cuticular nanostructures that enhance bioluminescent signaling efficiency also impose ecological constraints. Anti-reflective nanocoatings improve cuticle transparency and optical performance but typically increase surface adhesion, reducing fitness. In Luciola lusitanica, this trade-off is mitigated by temperature-sensitive nanocoatings that form only within a narrow thermal range, limiting habitat expansion. This study presents the first thermodynamic analysis of environmentally constrained nanocoating formation, demonstrating how small temperature fluctuations can destabilize protein-lipid self-assembly. These findings link nanoscale biophysics to ecological resilience, providing a framework to understand how the environmental sensitivity of structural self-organization shapes adaptation, species distribution, and evolutionary potential.
Yang T, Zhou Q, Bei Y
… +14 more, Meng D, Ai S, Zhang Y, Zhang J, Liu L, Chen H, Pan X, Yin X, Spanos M, Li G, Cretoiu D, Sluijter JPG, Rosenzweig A, Xiao J
Myocardial ischemia-reperfusion (I/R) injury remains a significant challenge in cardiovascular medicine, with its molecular mechanisms still not fully understood. Screening the GEO and Comparative Toxicogenomics Database...Myocardial ischemia-reperfusion (I/R) injury remains a significant challenge in cardiovascular medicine, with its molecular mechanisms still not fully understood. Screening the GEO and Comparative Toxicogenomics Database as well as spatial multi-omics data, we identify Cdkn2a, encoding p16, as a determinant in I/R injury. Cdkn2a expression is elevated in the myocardium of ischemic cardiomyopathy patients and p16 protein is enriched in cardiomyocytes within ischemic zones of myocardial infarction tissues. We find that p16 is consistently upregulated in both in vivo and in vitro I/R models, promoting apoptosis in neonatal rat cardiomyocytes (NRCMs) and human embryonic stem cell-derived cardiomyocytes (hESC-CMs) exposed to oxygen-glucose deprivation/reperfusion (OGD/R). p16 inhibition confers cellular protection, an effect also observed in in vivo I/R injury models. Mechanistically, p16 promotes binding of the RNA-binding protein CUGBP1 to the GRE sequence of Npas2 mRNA reducing its stability and translation, likely by inhibiting CDK4. This regulation impairs transcription of the Nasp2 target Slco1a4 and consequently bile acid transport, resulting in accumulation of intracellular bile acids and apoptosis. These findings identify p16-regulated bile acid transport as a driver of cardiac I/R injury.
Host defense against many Gram-positive bacteria and fungal pathogens is mainly provided by the Toll-dependent systemic immune response in Drosophila. While antimicrobial peptides active against these categories of patho...Host defense against many Gram-positive bacteria and fungal pathogens is mainly provided by the Toll-dependent systemic immune response in Drosophila. While antimicrobial peptides active against these categories of pathogens contribute only modestly to protection, Bomanin peptides are major effectors of the Toll pathway. Remarkably, flies deleted for the 55C locus that contains ten Bomanin genes are as sensitive as Toll pathway mutant flies to these infections. Yet, the exact functions of single Bomanins in resistance or resilience to infections remain poorly characterized. Here, we have extensively studied the role of these Bomanin genes. BomT1 functions in resistance to Enterococcus faecalis while playing a role in resilience against Metarhizium robertsii infection, like BomS2. BomT1 and BomT2 can prevent the dissemination of Candida albicans throughout the host, even though they are not sufficient to confer protection to immunodeficient flies against this pathogen in survival experiments. Furthermore, BomT1 and BomBc1 mutants are sensitive to an Aspergillus fumigatus ribotoxin. We conclude that 55C Bomanins have defined albeit sometimes overlapping roles in the different facets of host defense against infections.
The potential role of small interfering RNAs (siRNAs) produced from double-stranded RNA in aging has not been fully addressed. The networks of genes regulated by siRNAs and their partner Argonaute proteins are best under...The potential role of small interfering RNAs (siRNAs) produced from double-stranded RNA in aging has not been fully addressed. The networks of genes regulated by siRNAs and their partner Argonaute proteins are best understood in C. elegans, a pioneering model of aging and small RNA studies. Here, we describe synergistic lifespan extension of insulin/IGF-1 signaling (IIS) mutant age-1(hx546) by rde-4 or alg-3; alg-4 deficiencies. By analyzing gene expression and siRNA populations in these IIS and RNAi mutants, we show here that redundant spermatogenesis-specific Argonautes ALG-3 and ALG-4 are capable of regulating IIS, potentially through direct control of the Major Sperm Protein (MSP) genes in the germline. MSPs and MSP domains of some mammalian proteins are secreted and directly inhibit the Eph receptor (EphR). In turn, EphR interacts with and destabilizes PTEN, a major negative regulator of IIS. We show that enhanced MSP expression correlates with EphR mislocalization and elevated PTEN levels in oocytes of alg-3/4(-) worms. At the same time, ALG-3/4 expression is regulated by IIS. Thus, we propose mutual regulation of IIS and ALG-3/4 through secreted ligands.
Muscle stem cells (MuSCs) are essential for skeletal muscle repair. Following injury, MuSCs reside in low oxygen environments until muscle fibers and vascularization are restablished. The dynamics of oxygen levels during...Muscle stem cells (MuSCs) are essential for skeletal muscle repair. Following injury, MuSCs reside in low oxygen environments until muscle fibers and vascularization are restablished. The dynamics of oxygen levels during the regenerative process and its impact on muscle repair has been underappreciated. We confirm that muscle repair is initiated in a low oxygen environment followed by gradual reoxygenation. Strikingly, when muscle reoxygenation is limited by keeping mice under systemic hypoxia, muscle repair is impaired and leads to the formation of hypotrophic myofibers. Sustained hypoxia decreases the ability of MuSCs to differentiate and fuse independently of HIF-1α or HIF-2α. Prolonged hypoxia specifically affects the circadian clock by increasing Rev-erbα expression in MuSCs. Using pharmacological tools, we demonstrate that Rev-ERBα negatively regulates myogenesis by reducing late myogenic cell fusion under prolonged hypoxia. Our results underscore the critical role of progressive muscle reoxygenation after transient hypoxia in coordinating proper myogenesis through Rev-ERBα.
5'-Azacitidine (Aza) and 5-Aza-2'-deoxycytidine (Dac) are widely used demethylating drugs that directly integrate into nucleic acids. They are frequently used interchangeably, surprisingly as their selectivity is unique...5'-Azacitidine (Aza) and 5-Aza-2'-deoxycytidine (Dac) are widely used demethylating drugs that directly integrate into nucleic acids. They are frequently used interchangeably, surprisingly as their selectivity is unique from the other, with no predictors of response or clinical biomarkers to indicate drug preference. Using these drugs to induce demethylation, we combine DRIPc-Seq, Immunostaining, RNA-Seq and Mass spectrometry to uncover unique cellular responses. Activation of p53, exclusively by Aza, sustains accumulation of R-loops in CpG islands of p53 target genes. This effect is abolished by the removal of p53, compounded by destabilisation of heterochromatin marks. Dac treatment induces global chromatin modification, sustaining DNA damage, which is heightened in the absence of p53. Rescue experiments reverse the changes observed in the epigenome, demonstrating a direct role for p53 in preserving H3K9me3 and H3K27me3. These insights further our knowledge of how cells recognize and respond to methylation changes and uncover novel roles for p53 in modulation of the epigenome. Further to this, we determine a first in kind biomarker in p53 status that may be relevant for clinical settings.
Zurawska G, Sas Z, Jończy A
… +18 more, Mahadeva R, Slusarczyk P, Chwałek M, Seehofer D, Damm G, Mazgaj R, Skórzyński M, Kulecka M, Rumieńczyk I, Moulin M, Jastrzębski K, Waldron K, Mikula M, Etzerodt A, Serwa R, Miączyńska M, Rygiel TP, Mleczko-Sanecka K
Mild rupture of aged erythrocytes occurs in the spleen, resulting in hemoglobin (Hb) release, whereas pathological hemolysis characterizes several diseases. Hb detoxification is attributed to macrophages, but other route...Mild rupture of aged erythrocytes occurs in the spleen, resulting in hemoglobin (Hb) release, whereas pathological hemolysis characterizes several diseases. Hb detoxification is attributed to macrophages, but other routes of Hb clearance remain elusive. Here, we uncover that Hb uptake is chiefly executed by liver sinusoidal endothelial cells (LSECs) via macropinocytosis. Consistently, LSECs display proteomic signatures indicative of heme catabolism, ferritin iron storage, antioxidant defense, and macropinocytic capacity, alongside high iron content and expression of the iron exporter ferroportin. Erythrocyte/Hb transfusion assays demonstrate that splenic macrophages excel in erythrophagocytosis, while LSECs and Kupffer cells scavenge the spleen-borne hemolysis products Hb and erythrocyte membranes, respectively. High Hb doses result in transient hepatic iron retention, LSEC-specific induction of heme-catabolizing Hmox1, along with the iron-sensing Bmp6-hepcidin axis culminating in hypoferremia. Transcriptional induction of Bmp6 in LSECs is phenocopied by erythrocyte lysis upon phenylhydrazine and elicits a distinct transcriptional signature compared to iron. Collectively, we identify LSECs as key Hb scavengers, a function that establishes the spleen-to-liver axis for iron recycling and contributes to heme detoxification during hemolysis.
Effective visualization of 3D microscopy data is essential for communicating biological results. While scientific 3D rendering software is specifically designed for this purpose, it often lacks the flexibility found in n...Effective visualization of 3D microscopy data is essential for communicating biological results. While scientific 3D rendering software is specifically designed for this purpose, it often lacks the flexibility found in non-scientific software like Blender, which is a free and open-source 3D graphics platform. However, loading microscopy data in Blender is not trivial. To bridge this gap, we introduce Microscopy Nodes, an extension for Blender that enables the seamless integration of large microscopy data. Microscopy Nodes provides efficient loading and visualization of up to 5D microscopy data from Tif and OME-Zarr files. Microscopy Nodes supports various visualization modes including volumetric, isosurface, and label-mask representations, and offers additional tools for slicing, annotation, and dynamic adjustments. By leveraging Blender's advanced rendering capabilities, users can create high-quality visualizations that accommodate both light and electron microscopy. Microscopy Nodes makes powerful, clear data visualization available to all researchers, regardless of their computational experience, and is available through the Blender extensions platform with comprehensive tutorials.
Astrocytes, the most abundant glial cell type in the central nervous system, have traditionally been viewed from the perspective of metabolic support, particularly supplying neurons with lactate via glycolysis. This view...Astrocytes, the most abundant glial cell type in the central nervous system, have traditionally been viewed from the perspective of metabolic support, particularly supplying neurons with lactate via glycolysis. This view has focused heavily on glucose metabolism as the primary mode of sustaining neuronal function. However, recent research challenges this paradigm by positioning astrocytes as dynamic metabolic hubs that actively engage in lipid metabolism, especially mitochondrial fatty acid β-oxidation. Far from serving solely as an energy source, fatty acid ß-oxidation in astrocytes orchestrates reactive oxygen species-mediated signaling pathways that modulate neuron-glia communication and cognitive outcomes. This review integrates recent advances on astrocytic fatty acid ß-oxidation and ketogenesis, alongside other metabolic pathways converging on reactive oxygen species dynamics, including cholesterol metabolism and peroxisomal β-oxidation. In reframing astrocytic metabolism from energy provision to signaling, we propose new directions for understanding central nervous system function and dysfunction.
The convergence of artificial intelligence with biotechnology accelerates innovation but also introduces significant ethical and security risks. These require adaptive, flexible governance strategies that ensure that bre...The convergence of artificial intelligence with biotechnology accelerates innovation but also introduces significant ethical and security risks. These require adaptive, flexible governance strategies that ensure that breakthroughs can be managed responsibly while mitigating potential risks. [Image: see text]
Despite advances in synthetic biology and ecological understanding, the deployment of engineered microorganisms for bioremediation remains stalled due to outdated containment-centric narratives and regulatory frameworks....Despite advances in synthetic biology and ecological understanding, the deployment of engineered microorganisms for bioremediation remains stalled due to outdated containment-centric narratives and regulatory frameworks. A shift from a logic of to one of , is needed for a more responsible, culturally adjusted and scientifically grounded path toward leveraging biotechnology for planetary repair. [Image: see text]
Science and music are improvisational acts built on structure, discipline and intuition. And like music, science advances when ideas flow freely, when mistakes become motifs and when everyone in the room listens. [Image:...Science and music are improvisational acts built on structure, discipline and intuition. And like music, science advances when ideas flow freely, when mistakes become motifs and when everyone in the room listens. [Image: see text]
The exponentially increasing amount of omics data has created problems regarding ethical use of data generated by others. We address some of these issues and make suggestions on how they could be avoided or solved to ens...The exponentially increasing amount of omics data has created problems regarding ethical use of data generated by others. We address some of these issues and make suggestions on how they could be avoided or solved to ensure an open and fair research environment. [Image: see text]
TRIM2 is a mammalian E3 ligase with particularly high expression in Purkinje neurons, where it contributes to neuronal development and homeostasis. The understanding of ubiquitin E3 ligase function hinges on thoroughly i...TRIM2 is a mammalian E3 ligase with particularly high expression in Purkinje neurons, where it contributes to neuronal development and homeostasis. The understanding of ubiquitin E3 ligase function hinges on thoroughly identifying their cellular targets, but the transient nature of signaling complexes leading to ubiquitination poses a significant challenge for detailed mechanistic studies. Here, we tailored a recently developed ubiquitin-specific proximity labeling tool to identify substrates of TRIM2 in cells. We show that TRIM2 targets proteins involved in the endolysosomal pathway. Specifically, we demonstrate using biochemical and structural studies, that TRIM2 ubiquitinates TMEM106B at lysine residues located in the cytosolic N-terminal region. Substrate recognition involves a direct interaction between TRIM2 and a newly identified zinc-coordination motif in TMEM106B that mediates homodimerization, is required for specific protein-protein interactions, and lysosomal size regulation. We found that in addition to catalysis, the tripartite motif is involved in substrate recruitment. Our study thus contributes a catalog of TRIM2 effectors and identifies a previously unrecognized regulatory region of TMEM106B crucial to its function.
Folliculogenesis is a process that requires accurate interpretation of female physiological cues and elaborate coordination between the growing oocyte and its surrounding follicle cells, each being capable of responding...Folliculogenesis is a process that requires accurate interpretation of female physiological cues and elaborate coordination between the growing oocyte and its surrounding follicle cells, each being capable of responding to external signals. Here, we investigate the role of insulin signaling in Drosophila follicle cells. Using a phase separation-based reporter system, we observe a surge of insulin receptor activity in follicle cells during vitellogenic stages, a surge that is disrupted by a maternal high-sucrose diet. Single-cell RNA-seq reveals a diet-sensitive subpopulation of stage-8 follicle cells, which exhibits a reduction in CrebA-mediated transcription of genes for yolk and vitelline membrane proteins. Our results suggest a critical role of CrebA in implementing the stage-specific effect of insulin signaling to boost the secretory capacity of follicle cells. Mechanistically, CrebA is directly repressed by nuclear FoxO that is subject to insulin control, a regulatory axis that we show is conserved in human granulosa cells. This study delineates a mechanism through which insulin and nutrient cues act on a developmental transition via modulating the biosynthetic and secretory functions of the ovary.