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Li, S.

Publications and source records attributed to Li, S..

At least 91 records · Page 5Linked to original sources

Epstein-Barr virus transformation creates a methionine-dependent ferroptosis vulnerability in B cells

Epstein-Barr virus (EBV) causes over 200,000 cancers annually, including immunoblastic lymphomas in immunosuppressed hosts. Most transformed cells arrest, yet survive when deprived of the essential amino acid methionine. We instead find that EBV transformed lymphoblastoid cell lines (LCLs), which model the EBV latency III program-driven B-cell lymphoproliferative diseases of immunosuppressed hosts, rapidly die upon methionine restriction. Methionine restriction elevated LCL lipid reactive oxygen species and triggered ferroptosis. Whereas methionine restriction hypomethylates the EBV genome and triggers viral reactivation in latency I Burkitt cells by lowering the cellular methylation potential, the LCL latency III program instead redirected methionine toward redox defense, without altering the SAM/SAH ratio. Stable-isotope tracing revealed that latency III strongly induces transsulfuration, synthesizing cysteine de novo to support glutathione pools. The EBV oncoprotein LMP2A, which mimics B-cell receptor signaling, supported newly infected human B cell cystathionine-{beta}-synthase and cystathionine-{gamma}-lyase expression and methionine dependence, phenocopied by immunoglobulin crosslinking. In vivo, dietary methionine restriction impaired LCL xenograft outgrowth and depleted tumor cystine. Combined methioninase and cyst(e)inase administration blocked both cysteine sources, collapsed tumor glutathione levels, and triggered ferroptosis. Our results define methionine metabolism as a targetable ferroptosis vulnerability of EBV-transformed B cells. HighlightsO_LIMethionine restriction triggers EBV-transformed lymphoblastoid B cell ferroptosis C_LIO_LIEBV latency III induces transsulfuration to sustain LCL cysteine and glutathione C_LIO_LIMethioninase or dietary methionine restriction strongly impair LCL growth in vivo C_LIO_LIMethioninase plus cyst(e)inase collapses xenograft GSH levels and drives ferroptosis C_LI

biochemistry↗

Genic Position and Methylation Context Shape DNA Methylation-Expression Relationships in Rice Internode Development

Elongating rice internodes present a developmental gradient from dividing meristem to mature cells, providing an elegant pseudo-time course for study of plant vegetative development. We tested the hypothesis that DNA methylation regulates gene expression during rice internode development by integrating RNA-seq and bisulfite DNA sequencing across eight internode segments. Previously described topologically associated chromatin domain borders aligned with transcription start sites of constitutive expressed genes. CpG and CHG differential methylation was enriched in young segments, consistent with maintenance methylation; whereas CHH methylation showed similar differential abundance in young and old segments. CHH and CHG methylation in upstream regions, CpG methylation within gene bodies, and any methylation in 5' and 3' untranslated regions were permissive of moderate to high gene expression. Very low expression was associated with CpG methylation upstream, CHG and CHH methylation within gene bodies, and CpG and CHG methylation downstream. A nonrandom subset of genes, including cell wall-related glycoside hydrolases, lignin and tricin biosynthesis enzymes, and WD40 proteins, showed methylation-expression correlations, with expression changes enriched in triple-marked elements. These results suggest that internode phenotypes of DNA methylation machinery mutants relate to alteration of specific target genes, opening approaches for grass culm improvement for lodging resistance and biomass production. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/737558v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@b726eaorg.highwire.dtl.DTLVardef@5bd017org.highwire.dtl.DTLVardef@1bac873org.highwire.dtl.DTLVardef@1be3474_HPS_FORMAT_FIGEXP M_FIG C_FIG Significance statementStems of cereals and other grasses have an important function in supporting grain production and serving as a source of carbon for the bioeconomy. This study supports methylation of the cytosine bases of DNA as a regulator of chromatin structure and gene expression in the stems of rice. Different methylation contexts are implicated in specific roles in both positive and negative gene expression regulation that might be leveraged to improve stem properties.

plant biology↗

Scanning transcriptomes for nonlinear, domain-level similarities using hmSEEKR

Long noncoding RNAs (lncRNAs) play roles in gene regulation across kingdoms of life. However, lncRNAs with related functions often lack linear sequence similarity, making it difficult to leverage studies of one lncRNA to inform the understanding of others. We describe a k-mer-based hidden Markov model, hmSEEKR, that enables the scanning of transcriptomes for regions of non-linear sequence similarity to a query domain, without prior knowledge of where within the transcriptome the similarities may be located. When individual lncRNA domains were used as search features, hmSEEKR successfully identified regions in other RNAs that harbor non-linear sequence similarity and bind similar sets of proteins. Applying hmSEEKR to transcriptome-wide searches, we found that certain domains within the lncRNAs XIST, NEAT1, and MALAT1 exhibited widespread regional similarity to both lncRNA and protein-coding genes, while others were more unique, exhibiting similarity to [~]100 genes or fewer. Combinatorial searches uncovered RNAs containing sequential matches to core functional domains of XIST and NEAT1, and eCLIP-inferred protein-interaction networks within these RNAs more closely resembled those of XIST and NEAT1, respectively, than would be expected by chance, suggesting the searches recovered RNAs with similar biological properties. Finally, within annotated sets of cis-activating and cis-repressive lncRNAs, we observed opposing enrichments for similarity to domains associated with transcription-promoting complexes and heterogeneous nuclear ribonucleoprotein (hnRNP) binding, respectively, suggesting the enriched sequences may contribute to regulatory functions. hmSEEKR can be applied with minimal training data and enables the a priori discovery of RNA domains that share nonlinear similarity, offering a sequence-informed approach to discover functional elements within noncoding transcriptomes.

bioinformatics↗

Ancient pyroptotic machinery via GSDMA/B cleavage by LPS-activated caspase-1 in cartilaginous fish

Gasdermins are pore-forming effectors that mediate pyroptosis, an inflammatory form of programmed cell death characterized by membrane permeabilization and the release of intracellular contents. Phylogenetically, gasdermin members can be broadly divided into two major branches, the GSDME/PJVK branch and the GSDMA/B/C/D branch. Whereas the GSDME mediated pyroptosis was traced back to metazoans, the functional origins of GSDMA/B/C/D branch remain poorly understood. As a basal representative of the GSDMA-D lineage in cartilaginous fish, Callorhinchus milii GSDMA/B (CmiGSDMA/B) provides essential information for the ancestral state of this branch. Here, we functionally characterized CmiGSDMA/B and identified CmiCASP1 as its upstream protease. Mechanistically, Lipopolysaccharide (LPS) activates CmiCASP1 via its CARD domain, leading to cleavage of CmiGSDMA/B into two functionally distinct products, N241 and N288. N241 binds cell membrane to drive pyroptosis, whereas N288 suppresses N241-triggered cell death. Interestingly, N241 exhibits bactericidal activity against Gram-negative bacteria in vitro, suggesting that antimicrobial activity may have been an early feature of the GSDMA-D lineage. Collectively, these findings provide insight into a non-canonical, LPS-responsive, caspase-driven pyroptosis pathway in cartilaginous fish and reveal the dual-fragment antagonistic regulation within this branch.

evolutionary biology↗

A CSF Proteomic Clock Reveals Opposing Brain-Aging Programs and Predicts Neurological Disease Progression

Aging is the risk factor for neurological disease, yet the molecular architecture of human brain aging remains poorly defined. Here, we analyzed more than 10,000 cerebrospinal fluid (CSF) proteomes across multiple cohorts and proteomic platforms to developed a 249-protein CSF aging clock that accurately predicts age and generalizes across independent datasets. CSF brain-age acceleration was increased across diverse neurological diseases, associated with blood-brain barrier (BBB) dysfunction, and predictive of longitudinal cognitive decline, neuroimaging progression, and dementia conversion. A simplified 30-protein panel retained similar prognostic performance. Biologically, clock proteins resolved two opposing programs: pro-aging activation of immune, vascular/BBB, ECM and coagulation pathways marked by CHI3L1, CD14, VWF, LRG1 and LTBP2, and anti-aging collapse of neuronal, synaptic, axonal and structural-maintenance programs marked by NPTX2, COL1A2, NID1, CDH8 and PENK. Brain-wide single-cell and regional mapping linked these programs to disease-vulnerable compartments. These findings establish a molecular framework for biological brain aging and neurological disease vulnerability.

neuroscience↗

Evolutionary Origins of Molecular Programs Underlying Brain Circuitry

The vertebrate pallium harbors independently evolved structures that, nevertheless, support strikingly similar sensory and cognitive circuit architectures. The mechanisms and evolutionary timing driving the emergence of these parallel pallial circuits remain unelucidated. Here, we integrated spatial transcriptomic and single-nucleus RNA-seq datasets from eight representative vertebrate species spanning approximately 500 million years of evolution to reconstruct the evolutionary assembly of the primary sensory-allocortical (Pr-Al) molecular axis, a conserved cortical hierarchical axis defined in our prior work. We uncovered that Pr- and Al-like neuronal identities are deeply conserved across sarcopterygians, encompassing all tetrapods and lobe-finned fishes. Intriguingly, this ancestral neuronal homology is uncoupled from spatially partitioned patterning: only tetrapods further compartmentalized these Pr- and Al- neurons into distinct pallium regions. Functional enrichment of Pr- and Al- gene programs uncovered a conserved tetrapod genetic core suite including MAPK signaling and axon guidance pathways. This core toolkit underwent sequential functional refinement from amphibians through mammals. Notably, mammals and birds convergently evolved association-cortical molecular profiles enriched for synaptic regulatory genes to support advanced cognitive functions. Collectively, this work delineates a stepwise vertebrate pallium evolutionary paradigm that explains how conserved molecular modules shape spatially organized brain circuitry across deep evolutionary time.

evolutionary biology↗

Immune responses to infection modulate peripheral sympathetic neuron functions

The central nervous system interprets inflammatory signals in the body and directs the modulation of inflammatory responses by reflexively engaging peripheral sympathetic neurons1,2. This includes sympathetic neurons that innervate the spleen, which can regulate immune functions3-5 and modulate inflammation6-8. Yet, it is unclear if neuroimmune interactions involve specialised immunoregulatory sympathetic neurons, and if the immune system can reciprocally regulate peripheral sympathetic neurons to control these responses. Using retrograde tracing and single-cell transcriptomics, we find that spleen-innervating neurons are heterogeneous but do not exhibit a distinct transcriptional program indicative of specialisation for immune communication. However, we report that immune responses induced by pathogens can regulate postganglionic sympathetic neuron functions. Cytokines produced by immune cells downregulate expression of the neurotrophin nerve growth factor in spleen mesenchymal cells, leading to organ-specific sympathetic nerve retraction from the spleen. Concurrently, splenic type I interferon signalling induces inflammatory gene expression in neurons and suppresses neuron excitability. Chemogenetic activation of sympathetic neurons demonstrates an impaired anti-inflammatory capacity in the spleen during infection. These results reveal regulation of sympathetic neuronal functions by the immune system, which could support optimal generation of immune responses against pathogens.

immunology↗

OpenGerminal: an open-source implementation of the Germinal antibody design pipeline

Germinal is a recently described computational pipeline for de novo antibody design that combines AlphaFold-Multimer hallucination with antibody language model guidance to generate epitope- targeted antibodies. Germinal identified binders with nanomolar-to-low-micromolar affinities by testing only 43-101 designs per target across four diverse antigens, establishing it as a practical tool for epitope-directed antibody design accessible to standard academic laboratories. As this architecture is itself very recent, systematic replacement and benchmarking of its individual components remains largely unexplored, yet offers a valuable opportunity to probe the robustness of the underlying design. We present OpenGerminal, which replaces PyRosetta with a fully open- source stack comprising OpenMM 8.5.1, FreeSASA, FASPR, Biopython, and sc-rs v1.0.0, and adopts AbLang1 (ablang2 v0.2.1) as the sole antibody language model in place of IgLM. Benchmarking on two VHH targets (PD-L1 and IL-3) reveals that OpenGerminal achieves a markedly higher cofolding pass rate (PD-L1: 33.7% vs. 18.6%; IL-3: 24.6% vs. 8.0%) with equivalent or improved Chai-1 structural confidence metrics in accepted designs, at the cost of a modest increase in per-trajectory computation time ([≥]1.5x). Multi-chain target support is also extended and verified to run without error on the official insulin example. OpenGerminal provides the first systematic benchmarking of IgLM versus AbLang1 within the Germinal architecture, and its fully open-source component stack broadens the range of deployment contexts in which the pipeline can be used. Availability and ImplementationSource code is freely available at https://github.com/teaninja/OpenGerminal under the Apache 2.0 license. Persistent archives with DOIs are available at https://doi.org/10.5281/zenodo.20755400 (code) and https://doi.org/10.5281/zenodo.20756013 (container image). OpenGerminal is implemented in Python and distributed as an Apptainer container (opengerminal_v1.0.0.sif). Installation instructions and example configurations are provided in the repository. Contactbh7bu@virginia.edu Supplementary informationSupplemental Figure 1 is available online.

bioinformatics↗

Cardiolipin modulation of MmpL3 in mycobacteria

The complex cell envelope of mycobacteria is characterized by the presence of a unique outer membrane (OM) rich in mycolic acids (MAs). These long-chain, branched fatty acids confer extreme hydrophobicity to the OM, in part rendering the mycobacterial envelope impermeable to antibiotics and host defences. How MAs are transported from the inner membrane (IM) to the OM is largely unknown. The integral membrane protein MmpL3 plays an essential role in this process, but the mechanism(s) by which it exploits the proton motive force to flip and/or release MAs at the IM, in the form of trehalose monomycolates (TMMs), remains elusive. Here, we reconstitute and quantify the proton translocation activity of MmpL3 in artificial lipid bilayers, and discover a novel role for the phospholipid species, cardiolipin (CL), in regulating MmpL3 function. We find that mutations in conserved residues, or binding of known inhibitors in the central channel of MmpL3 do not diminish proton translocation activity. Instead, the specific presence of CL abolishes proton translocation by MmpL3 in vitro. Furthermore, we establish that an MmpL3 variant containing substitutions in a CL-binding site predicted in silico is no longer modulated by CL in vitro, and is unable to support growth of Mycobacterium smegmatis. Our work provides previously unappreciated insights into lipid regulation of MmpL3 activity in mycobacteria, and expands the guiding principles for the development of anti-mycobacterial inhibitors targeting this essential transporter. SignificanceMycobacterial species, including the human pathogen Mycobacterium tuberculosis, are surrounded by a double-membrane cell envelope that makes them intrinsically resistant to many antibiotics. Specifically, the outer membrane (OM) contains unique lipids called mycolic acids (MAs), whose transport pathway across the envelope is poorly understood. In this study, we characterized the biochemical activity of the essential MA transporter MmpL3, and uncovered a novel mechanism for lipid-mediated functional regulation. Our work highlights the importance of protein-lipid interactions in defining transporter activity, provides insights into MA transport and OM assembly in mycobacteria, and sets the stage for the development of anti-mycobacterial strategies.

biochemistry↗

Catalytic rewiring of RuvC-II catalytic site activates trans-cleavage in Fanzor2

Fanzors are eukaryotic RNA-guided endonucleases that mediate programmable cis-cleavage in eukaryotic cells, but their potential target-induced collateral (trans) cleavage activity remains largely unexplored. Here, we show that catalytic rewiring of the RuvC-II catalytic site activates robust trans-cleavage activity in Acanthamoeba polyphaga mimivirus Fanzor2 (ApmFz2). The representative variant ApmFz2-EP displayed DNA- and RNA-triggered trans-cleavage, attenuated cis-cleavage, minimal TAM dependence, and activation by as few as seven nucleotides of guide-target complementarity. Mechanistic analyses indicate that relieving steric constraints surrounding the conserved alternative glutamate within the RuvC-II activates trans-cleavage and reshapes target-recognition specificity. Coupling ApmFz2-EP with nucleic acid amplification enabled FINDER, a Fanzor-based diagnostic platform for sensitive pathogen detection and broad detection across genetically diverse target subtypes. In addition, the mismatch-sensitive ApmFz2-EA variant enabled specific single-nucleotide variant (SNV) genotyping. Together, this work expands the functional scope of Fanzors and identifies catalytic-center engineering as a strategy for developing compact, programmable nucleic acid diagnostics.

bioengineering↗

HyRes: Accurate Physics-Based Simulation of Dynamic Protein Structures and Interactions in Complex Environments at Scale

Intrinsically disordered proteins and regions (IDPs) are ubiquitous cellular regulators. Uncovering how their transient, multivalent interactions organize and fine-tune cellular processes requires transferable methods capable of deriving dynamic conformational ensembles across diverse environments at scale. Here, we present HyRes, a physics-based, hybrid-resolution protein model with atomistic backbones and intermediate-resolution sidechains that bridges the gap between atomistic accuracy and computational efficiency. Evaluated across [~]100 IDPs, HyRes generates atomistic ensembles that match or outperform state-of-the-art all-atom force fields in reproducing experimental chain dimensions, transient tertiary contacts, and local secondary structures. Demonstrating exceptional transferability, HyRes accurately captures dynamic IDP interactions in dilute phases, condensed phases, and amyloid fibril fuzzy coats. Finally, we leverage HyRes scalability to generate disordered ensembles for [~]30,000 IDPs from the human proteome and DisProt, revealing strong correlation between residual structures and cellular function and localization. HyRes and this open-access database provide unprecedented resources for IDP biology and deep learning.

biophysics↗

Field–Flow–Front mapping of breast cancer evolutionary dynamics in situ

Tumour progression reflects not only which clones arise but where, when and in what context they expand--dimensions genotype-centred reconstructions leave unresolved. Here we reconstruct breast cancer evolution in situ across 34 Visium HD, 16 Xenium, 32 MIBI-TOF and 10 CODEX samples, serial-section 3D reconstruction, single-cell and bulk transcriptomes, and genome-wide CRISPR dependency profiles. We partition tumours into 296 cancer microzones--stroma-bounded units within which expansion is reconstructed--and define in each a Cancer Progression Metric(CPM) coupling a transcriptomic clock to expansion geometry. Projected onto tissue, CPM yields a Field-Flow-Front model rendering progression as a continuous physical process and resolving subclonal architecture into spatially coherent domains rather than predefined branches. Unexpectedly, the most advanced fronts were not the most proliferative but low-dependency, slow-cycling populations with directional expansion, driven by an extracellular matrix programme whose evolutionary force exceeded inflammation by nearly an order of magnitude yet whose genes were the least cell-autonomous. Under chemotherapy it persisted while its clonal carriers reshuffled, marking a transferable, stroma-coupled front process--not a fixed clone--as the unit of advance. Distilled into an evolutionary advantage load, this front process predicted recurrence and survival across independent cohorts and improved on conventional staging, establishing a tissue-embedded paradigm for mapping tumour evolutionary dynamics, from local fronts to patient outcome.

Cancer Biology↗

A human intracranial map of consciousness returning from anesthesia

How consciousness arises from the brain remains a central yet unsolved question. Although substantial effort has been devoted to characterizing the neural correlates of conscious perception during wakefulness, how consciousness re-emerges from unconscious states remains poorly understood. Here, we took advantage of the rare opportunity to record human intracranial local field potentials from propofol-induced general anesthesia through the transition to behavioral engagement and subsequent full wakefulness, capturing both the stable states of unconsciousness and consciousness and the reconstituting neural dynamics that bridge them. Anesthesia cannot be defined by any single electrophysiological signature; rather, it is an organized low-frequency regime characterized by a constellation of coordinated neural phenomena, including aperiodic slow waves, alpha/beta periodicity, global alpha synchronization, and slow-wave-alpha/beta phase-amplitude coupling. Following anesthetic cessation, this regime progressively dissolved as neural excitability and dynamical complexity climbed. The appearance of conscious behavior coincided with a fast and dramatic transformation in high-gamma activity, from stochastic and unpredictable bursts to structured responses that were distributed, task-selective, and event-locked. These findings suggest that the recovery of consciousness is a multiscale reorganization in which distinct neural underpinnings rise and fall. Together, this work charts an electrophysiological map of how conscious cognition is extinguished, reconfigured, and restored in the human brain.

neuroscience↗

Healing cascades and infections in wounds monitored using a wearable sensor of gaseous flux

Capabilities for quantitative monitoring of chronic wounds remain an unmet clinical need, as existing diagnostic approaches rely on semiquantitative evaluation of symptoms that lack sensitivity especially during early stages of infection. Here we present a scheme for tracking wound physiology that leverages a miniature, wireless skin-interfaced device for non-contact, transient measurements of the flux of volatile organic compounds (VOCs) and water vapor from the wound microenvironment. Unlike emerging smart bandage platforms that rely on physical contact with the fragile wound bed to interrogate liquid-phase biomarkers, this strategy uses an engineered microclimate and suspended suite of sensors to measure the diffusive transport of wound-derived gases across the wound surface but separated from it. The result enables quantitative evaluation of metabolic activity and healing progression without perturbing the healing tissues. In biofilm growth models of Staphylococcus aureus, measurements demonstrate that trends in VOC flux correlate strongly with bacterial growth kinetics and precede any visible biofilm formation. Longitudinal monitoring in infected murine wound healing models shows that concurrent measurements of water vapor and VOC flux provide complementary physiological insights, capturing both the trajectory of barrier restoration and the dynamics of bacterial burden. The findings establish this non-contact sensing scheme as a distinct and clinically translatable paradigm for wound monitoring, with broad implications for non-invasive surveillance of disease states in which tissue metabolic activity and skin barrier integrity serve as actionable physiological readouts. Significance StatementLimited capabilities in continuous, quantitative assessment of a wound make early diagnosis and effective management challenging, particularly in cases of infection that rapidly progress before symptoms appear. Non-contact approaches for wound monitoring that preserve fragile tissue can transform wound care. In this context, gaseous flux from the wound bed provides an integrative measure of microbial activity and barrier restoration. This study establishes a wearable sensing platform that quantifies these fluxes in real time, enabling early infection detection and temporal tracking of wound healing. These results highlight a path toward personalized treatment strategies and reduced reliance on episodic clinical evaluation.

bioengineering↗

Sensory neurons encode long-term inflammatory memory that promotes gastric regeneration and tumorigenesis

Inflammatory memory has emerged as a fundamental principle by which prior injury shapes future tissue responses, yet whether sensory neurons participate in long-term tissue memory remains unknown. Here, we show that vagal sensory neurons acquire a durable, experience-dependent state following gastric injury or Helicobacter pylori infection, leading to enhanced regeneration, metaplasia, and tumor progression upon re-injury. This neuronal program is stable, functionally transferable, and sufficient to drive epithelial responses in vivo. Mechanistically, injury-activated ILC2s establish sensory neuronal memory through IL-13-dependent epigenetic remodeling, inducing SMYD4-mediated H3K4 trimethylation and promoting CGRP-dependent activation of gastric epithelial cells. Together, our findings support a model in which tissue memory is not restricted to epithelial or immune compartments but emerges through coordinated long-term adaptations across multiple cellular systems. Within this framework, sensory neurons provide a persistent substrate for recall responses, linking prior inflammatory experience to sustained epithelial plasticity and cancer susceptibility. HIGHLIGHTSO_LISensory neurons function as a durable compartment of tissue memory. C_LIO_LICGRP-RAMP1 signaling couples neuronal memory to gastric stem cells. C_LIO_LIILC2-derived IL-13 establishes sensory neuronal memory programs. C_LIO_LISMYD4-mediated H3K4me3 stabilizes long-term neuronal memory. C_LIO_LINeuronal memory promotes gastric regeneration and tumor susceptibility. C_LI

cancer biology↗

A Tripartite Map of the Ventromedial Prefrontal Cortex

The ventromedial prefrontal cortex (VMPFC) has been repeatedly implicated in affect, valuation, and social cognition, yet how these diverse functions are organized within a single cortical territory has remained unresolved. Here, we integrate large-scale meta-analysis, individual-level task fMRI, artificial neural-network encoding models, and multimodal connectivity analyses to reveal the internal functional architecture of the human VMPFC. Across four complementary studies, we identify a robust tripartite organization along the anterior-posterior axis, comprising posterior affective, middle valuation, and anterior social functional motifs. Connectivity fingerprinting demonstrates that each motif is preferentially embedded within distinct large-scale brain networks, providing a mechanistic account of VMPFC functional specialization. This organization is reproducible at the level of individual subjects, generalizes to naturalistic stimuli, extends across development, and shows cross-species correspondence with non-human primates and multiple neurobiological markers. Together, these findings resolve a long-standing organizational question and establish a biologically grounded framework for interpreting VMPFC function.

neuroscience↗

Ubiquitin selective ribosome profiling reveals systematic principles of co-translational quality control

Protein biogenesis is a stress- and error-sensitive process that can lead to nascent protein misfolding and aggregation, challenging cellular proteostasis.1 Co-translational ubiquitination (CTU) is a critical surveillance mechanism,2,3 yet its regulatory principles remain unclear due to limited known substrates and the lack of translatome-wide methods to query CTU. Here, we introduce UbSeRP, an approach that enables ubiquitin linkage-specific, and translatome-wide mapping of CTU. Focusing on ribosome-associated quality control (RQC), we expand the known endogenous RQC substrates in S. cerevisiae from few4-7 to thousands, reveal that only a subset of all identified disomes undergoes RQC, and uncover biophysical features of nascent chains that predict RQC engagement. We also identify widespread RQC-independent ubiquitination of nascent proteins, implicating broader roles of CTU in protein complex assembly. In a chronological aging model, we show that aging remodels translation and diminishes RQC engagement, favoring RQC-independent proteasomal pathways. Our findings provide systematic insight into the determinants and adaptability of CTU in maintaining proteostasis under changing physiological conditions.

biochemistry↗

Multisensory integration of a host metabolite coordinates bacterial predation of macrophages

The crisis of antimicrobial resistance demands new strategies that circumvent conventional killing. Here, we show that Yersinia pseudotuberculosis intercepts host mesifurane, a mimic of quorum-sensing signal AI-2. Rather than acting through a single receptor, mesifurane is directly and independently sensed by three receptor classes, YcrA, NarX, and CusR, that converge on a "Sense, Arm, Recruit" program. YcrA drives chemotaxis toward host cells; NarX-NarP licenses T6SS-mediated killing; and CusR amplifies AI-2 production to recruit more bacteria. YcrA is conserved across Gram-negative pathogens, creating a therapeutic vulnerability. Suramin sodium, a repurposed drug blocking YcrA, disarms this circuit without inhibiting growth. In murine sepsis, suramin sodium conferred 80-90% survival against WHO critical-priority pathogens, including carbapenem-resistant A. baumannii, E. coli, and P. aeruginosa, even when delayed 8 hours post-infection, without selecting for resistance. These findings establish that disrupting sensory perception, rather than viability, provides an anti-infective strategy bypassing resistance while imposing minimal selective pressure.

microbiology↗