Biology subjects

Wilson, C.

Publications and source records attributed to Wilson, C..

At least 19 recordsLinked to original sources

bioRxiv2026

Cofilin Suppresses Tau-Induced Defects in Dense-Core Granule Formation and Aβ-Induced Neurodegeneration

Intracellular neurofibrillary tangles formed from hyperphosphorylated tau and extracellular amyloid plaques containing aggregated A{beta}-peptides, specific cleavage products of the Amyloid Precursor Protein (APP), are the primary histopathological hallmarks of Alzheimers Disease (AD), the leading cause of dementia in humans. However, the initiating steps that lead to these pathologies and early neurodegeneration, and the mechanisms by which tau- and A{beta}-induced effects might be linked remain unclear. Using the prostate-like secondary cell (SC) in Drosophila, we recently showed that A{beta} modulates normal APP- and membrane-associated protein aggregation in the dense-core granule (DCG) compartments of the regulated secretory pathway by interfering with subsequent membrane:DCG dissociation. This disrupts endolysosomal trafficking and propagates the resulting endolysosomal defects to other cells that endocytose the secreted abnormal DCG proteins. Here we show that overexpressing human tau also disrupts DCG aggregation and membrane:DCG dissociation inside SC secretory compartments, leading to increased endolysosomal targeting of these compartments. In a genetic screen, we find that knockdown of cofilin, which encodes an actin-severing protein required for dynamic remodelling of microfilaments, generates a similar phenotype. Consistent with this, overexpression of Cofilin, which is known to suppress tau-induced neurodegeneration in flies, reduces tau-induced DCG defects in SCs. Indeed, we find that Cofilin overexpression also suppresses A{beta}-induced degeneration in the fly eye. We conclude that membrane:DCG aggregate dissociation in DCG compartments is disrupted by both tau- and A{beta}-induced genetic changes that are relevant to AD, and this partially involves inhibition of actin cytoskeleton dynamics. Increasing actin remodelling activity can suppress neurodegeneration induced by both tau and A{beta}, suggesting that this process provides an important functional link between them that might be targeted therapeutically.

neuroscience↗

bioRxiv2026

Rab11-exosome biogenesis regulators mediate Aβ-induced intercellular propagation of endolysosomal trafficking defects and neurodegeneration

Alzheimer's Disease (AD) is characterised by two histopathological hallmarks, intracellular tau-containing neurofibrillary tangles and extracellular amyloid plaques containing {beta}-amyloid (A{beta}), a specific cleavage product of Amyloid Precursor Protein (APP). Initiation of A{beta}-induced neuronal pathology, however, has been postulated to involve intracellular events affecting endolysosomal trafficking that can propagate between cells. Recent studies in non-neuronal Drosophila secondary cells (SCs) have revealed that A{beta} interferes with APP-regulated protein aggregation events, which package signalling molecules into insoluble dense-core granules (DCGs) during normal regulated secretion, inducing endolysosomal defects that are transferred to other cells. Here, using SCs, we show that knockdown of the gene encoding accessory ESCRT-III protein Chmp5, which selectively regulates the formation of intraluminal vesicles (ILVs) inside SC DCG compartments that are subsequently released as Rab11-exosomes, inhibits propagation of A{beta}-induced endolysosomal trafficking defects. Furthermore, knocking down Chmp5 or other accessory ESCRT-III genes also suppresses A{beta}-induced, neurodegeneration-dependent morphological defects in the Drosophila eye. We conclude that genes controlling the Rab11-exosome biogenesis pathway play a key role in both A{beta}-induced endolysosomal trafficking defects associated with aberrant regulated secretion and cellular events leading to neurodegeneration. Our findings indicate these processes are linked and may suggest new target pathways for future development of AD therapeutics.

neuroscience↗

bioRxiv2026

PI3K-AKT activation determines oncogenic RAS-induced hypertranscription and replication stress

Hypertranscription and transcription-replication conflicts (TRCs) are frequent features of cancer cells. RAS oncogenes promote hypertranscription to allow cell growth and proliferation, which can the lead to TRCs. Here, we report that hyperactivation of the PI3K-AKT signalling pathway is required for TRCs induced by RAS oncogenes. Oncogenic HRAS causes more TRCs than oncogenic KRAS or BRAF, because HRAS hyperactivates PI3K. PI3K hyperactivation is associated with in glycogen synthase kinase-3{beta} (GSK3{beta}) inhibition, increased E2F and MYC transcription programmes, increased nascent transcription of ribosome biogenesis genes and small nucleolar RNAs (snoRNA) expression. Small molecule inhibition of PI3K signalling prevents RAS-induced replication stress, and small molecule PI3K activation promotes replication stress. RAS-induced TRCs require a cooperation of MAPK and Pi3K signalling, S phase entry and hypertranscription. Our findings suggest a mechanistic explanation for replication stress variability between RAS activation models and identify PI3K pathway activation as a potential new determinant of TRCs in cancer.

cancer biology↗

bioRxiv2025

Functional dissection of Leishmania major membrane components in resistance to cholesterol-dependent cytolysins

Bacteria use cholesterol-dependent cytolysins (CDCs) to damage eukaryotes. While well-studied in mammals, the mechanisms by which CDCs bind to and kill protozoans remains unclear. CDCs bind to the human pathogen Leishmania major, but only kill in the absence of sphingolipids. The contribution of other leishmanial membrane components to CDC binding and cytotoxicity remains unknown. Here, we used genetic knockouts and inhibitors to determine the contribution of key membrane components to CDC binding and killing in L. major. We analyzed toxin binding and killing using flow cytometry and western blotting. Loss of the virulence factor GP63 enhanced toxicity of perfringolysin O, but not streptolysin O. Plasmenylethanolamine and lipophosphoglycan had minimal contributions to CDC binding and cytotoxicity. Removal of sterols protected cells from CDCs, yet failed to reduce binding. We used CDCs defective in engaging glycans or cholesterol to confirm that CDCs deficient in sterol binding, but not glycan binding, could bound to L. major. Thus, in non-mammalian systems, CDCs may rely on glycans for binding, while using sterols for pore-formation. This suggests that CDCs may not be sterol-specific probes in some non-mammalian systems. We conclude that early-branching eukaryotes use distinct mechanisms from mammals to limit CDC pore-formation and killing.

cell biology↗

bioRxiv2025

Comparing the evolvability of an ancestrally reconstructed and modern adenylate kinase

Directed evolution transformed protein engineering by providing a customizable framework for generating enzymes with improved catalytic performance across diverse functions. Yet modern enzymes often stall during directed evolution because populations become trapped on local fitness peaks. Researchers have suggested that ancestral enzymes offer better starting points because they are typically more thermostable. Here we propose and experimentally test an alternative explanation that does not depend on ancestral thermostability. We posit that ancestrally reconstructed sequences are unusually evolvable because they are inferred from the evolutionary lineages that survived to produce extant proteins. Less evolvable ancestors, and the trajectories emanating from them, disappeared by extinction and therefore do not contribute to reconstructed ancestors. Using thermophilic ancestral and modern adenylate kinases, we performed independent single-round selection experiments for activity in vivo and in vitro. In both settings, the ancestral enzyme tolerates a larger number of mutations, yielding more viable variants with greater genetic diversity than its modern descendants. Because mutational robustness promotes evolvability, these results support an intrinsic evolvability of reconstructed ancestral sequences that makes them superior launch points for directed evolution.

biochemistry↗

bioRxiv2025

Complete de novo assembly and re-annotation of the zebrafish genome

The zebrafish (Danio rerio) is widely used in vertebrate research, but its reference genome assembly has contained extensively unresolved regions across both euchromatic and heterochromatic compartments. The previous reference genome assembly, GRCz11, consisted of 19,725 contigs assembled into 1,917 scaffolds. Recent advances in both long-read sequencing technologies and genome assembly algorithms have made "complete" genome assemblies possible for the first time. We used homozygous fish from two lab strains, "Tubingen" and "AB," for de novo genome assemblies. The new assemblies incorporated 7% more genomic sequence than GRCz11 and an additional 130 million bases of previously unassembled sequence. RefSeq annotation incorporating newly generated Iso-Seq cDNA sequences have added notable increases in mRNAs (68%), lncRNAs (47%), and misc_RNAs (1099%). Two assemblies have been elevated to reference genome status (GRCz12tu and GRCz12ab). We generated an additional 40 draft haplotypes to create a zebrafish pangenome resource and demonstrate its utility for variant analysis.

genomics↗

bioRxiv2025

Self-supervised AI reveals a lethal discohesive phenotype in lung adenocarcinoma

Applications of artificial intelligence (AI) to histopathology are now common, but most require supervision which inherently limits their scope. By using self-supervised learning (SSL), we discover and quantify the full range of histopathological appearances in a disease, and associate them with clinicopathological ground truths such as prognosis. We used this approach to discover under-appreciated morphologies of lung adenocarcinoma (LUAD), using a highly characterised resected tumour cohort of over 4000 slides from over 1000 patients. By constructing an authoritative lexicon of recurrent LUAD appearances, we ab initio discovered several stromal morphologies strongly predictive of outcome. With multimodal data integration and external dataset validation, we propose that epithelial discohesion is lethal, but only in the context of immunologically cold stroma. Both these morphological features are independent of current prognostic schema. Crucially, we describe these features in the context of real-world diagnostic histopathology, giving them immediate clinical translatability. Statement of SignificanceHistopathology relies heavily on epithelial morphology, often neglecting the stroma. We use self-supervised AI to identify under-appreciated morphologies in LUAD linked to poor outcome and validate these observations in an external cohort, demonstrating the utility of self-supervised AI as a powerful biological discovery tool.

cancer biology↗

bioRxiv2025

A Covalent PFKL Activator Suppresses Tumor Growth

Glycolysis fuels vital cellular functions and its dysregulation is implicated in cancer, neurodegeneration, antibiotic resistance and diabetes. The glycolytic dependency of cancer, known as the Warburg effect, presents a key vulnerability for developing targeted anticancer agents but remains challenging due to metabolic heterogeneity and resistance. Here, we developed a first-in-class covalent phosphofructokinase-1 liver type (PFKL) activator that induces metabolic imbalance coupled to delivery of a cytotoxic payload to cancer cells in vitro and in vivo. The electrophile-drug conjugate (EDC) site-specifically and proteome-wide selectively modifies K677 in the allosteric effector site to stabilize the R-state tetramer of PFKL and destabilize cell metabolism. We introduce EDCs as a new delivery mechanism analogous to antibody-drug conjugates but differentiated by selective covalent targeting of intracellular proteins.

biochemistry↗

bioRxiv2025

The 7SK small nuclear ribonucleoprotein links the cell responses to transcription and replication stress by promoting replication fork reversal and homologous recombination

The 7SK-small nuclear ribonucleoprotein complex (7SK-snRNP) plays a crucial role in the response to transcription stress, releasing positive transcription elongation factor P-TEFb to sustain RNA polymerase II activity when transcription is blocked. Many conditions that block transcription also block DNA replication, causing replication stress, and 7SK-snRNP components are putative tumour suppressors with roles in transcription-replication conflicts and double-strand break repair. Here, we investigate potential roles of 7SK-snRNP components in the response to replication stress induced by chemotherapy agents with and without additional impact on transcription. We report that HEXIM1 and LARP7 promote replication fork slowing in response to agents that cause both replication- and transcription stress, in a manner consistent with their canonical 7SK-snRNP functions. Our data suggest that this role in fork slowing is mainly through facilitating RAD51-mediated replication fork reversal rather than transcription-replication conflicts. HEXIM1 and LARP7 promote RAD51 recruitment to replication-associated DSBs or post-replicative gaps under conditions of transcription stress such as induced by camptothecin or BET inhibitors and support HR at direct DSBs. In contrast, HEXIM1 and LARP7 are not required for HR in response to hydroxyurea, which does not cause transcription stress. Our data support that LARP7 roles during replication stress are independent of its reported interaction with BRCA1, and that both LARP7 and HEXIM1 promote survival in response to replication stress-inducing agents. 7SK-snRNP components are not recruited to stressed replication forks and RNA polymerase II inhibition phenocopies loss of these proteins. Taken together, our data support a model where 7SK-snRNP modulation of RNA polymerase II activity helps facilitate RAD51 function under transcription stress conditions, thereby connecting the cell responses to transcription- and replication stress.

molecular biology↗

bioRxiv2025

Dysregulation of energy metabolism and calcium homeostasis in iPSC-derived neurons carrying Presenilin-1 M146L gene mutation

Impaired cellular activities, particularly in highly active cells such as neurons, are primarily supported by metabolic abnormalities and failures in Ca{superscript 2} homeostasis. Here, we provide an integrative analysis of human iPSC-derived neurons (iNs) carrying the Presenilin-1 M146L gene mutation (PS1M146L) and control cells (PS1control). PS1M146L iNs exhibited abnormal Ca{superscript 2} dynamics, a significant increase in key parameters of mitochondrial respiration, and higher intracellular ROS levels. KCl-evoked depolarisation was significantly lower in PS1M146L, suggesting a failure in maintaining the electrochemical gradient across the plasma membrane. Following thapsigargin stimulation, mitochondrial Ca{superscript 2} levels ([Ca{superscript 2}]m) were significantly reduced in PS1M146L, while [Ca{superscript 2}]m did not differ significantly between genotypes after treatment with bradykinin, suggesting that impairments in the [Ca{superscript 2}]m homeostasis are particularly evident under stress conditions and do not impact the 1,4,5-triphosphate (IP3) pathway. Since iNs of both genotypes were sensitive to the MCU-1 inhibitor, the deficits observed in PS1M146L could be the consequence of impairments in the ER-mitochondria contacts. Our results illustrate the utility of iNs carrying PS1 mutations in understanding how human neurons alter relevant pathways before neurodegeneration.

neuroscience↗

bioRxiv2025

Tyrosine kinase inhibitors affect sweet taste and dysregulate fate selection of specific taste cell subtypes via KIT inhibition.

Taste dysfunction, or dysgeusia, is a common side effect of many cancer drugs. Dysgeusia is often reported by patients treated with anti-angiogenic tyrosine kinase inhibitors (TKIs), which inhibit receptor tyrosine kinases (RTKs). However, the mechanisms by which TKIs cause dysgeusia are not understood, as the role of RTKs in adult taste homeostasis is unknown. Here, we find that treating adult mice with the TKI cabozantinib shifts the fate of differentiating functional taste cell subtypes within taste buds. Through behavioral assays, we find this cell fate shift leads to blunted responses to sweet in cabozantinib-treated mice. Finally, we show that inducible knockout of the RTK KIT, which is inhibited by cabozantinib, phenocopies taste cell fate shifts induced by TKI treatment. Our results establish KIT as a regulator of taste cell homeostasis and suggest that KIT inhibition may underlie TKI-induced dysgeusia in patients. SummaryKIT signaling blockade by tyrosine kinase inhibitors alters the fate of functional taste bud cell subtypes.

neuroscience↗

bioRxiv2025

The HOTAIRM1-miR-222 Axis Regulates Venetoclax Resistance and Defines a High-Risk Subset in Pediatric t(8;21) Acute Myeloid Leukemia

Although acute myeloid leukemia (AML) with the RUNX1::RUNX1T1 fusion [t(8;21)(q22;q22.1)] defines a distinct cytogenetic subtype, differences in treatment response suggest additional molecular contributors beyond chromosomal abnormalities. Deregulated hematopoietic lineage-specific long non-coding RNAs (lncRNAs) contribute to leukemogenesis and therapy resistance. To investigate their role in t(8;21) AML, we performed whole-transcriptome sequencing of pediatric patients and age-matched healthy controls, identifying significant downregulation of lncRNA HOTAIRM1, a regulator of myeloid differentiation (adjusted P < 0.05). This was confirmed in a single-cell RNA-sequencing dataset (GSE116256) and the Leukemia MILE dataset (GSE13159, P=0.03). Validation of expression in our study cohort using qPCR specifically demonstrated significant downregulation of the myeloid specific isoform, HOTAIRM1 - HM1V2 (P<0.0001). Analysis of downstream pathways activated by HM1V2 loss identified miR-222, an oncomiR, as a de-repressed target (P=0.01). Elevated miR-222 expression was observed across AML cell lines (P<0.05), leukemic stem and progenitor cells (GSE117090, P<0.05), AML plasma-derived exosomes (GSE142699, P<0.0001), the current study dataset (P<0.0001), and the TARGET AML dataset (P<0.0001). Restoring HM1V2 expression with epigenetic agents azacytidine and panobinostat induced apoptosis in venetoclax-resistant Kasumi-1 cells (P < 0.01), through suppression of miR-222 (P < 0.01) and downregulation of anti-apoptotic proteins BCL-xL and MCL-1 (P < 0.05), key mediators of the venetoclax resistance mechanism. Machine learning based feature selection and Cox regression analysis showed that high miR-222 expression predicts poor outcome in pediatric t(8;21) AML, validated in both our institutional pediatric AML cohort (P < 0.05) and the multi-institutional TARGET cohort (P < 0.0001). Together, our findings highlight an epigenetic based approach to restore isoform-specific HM1V2 pathway function in venetoclax-resistant AML cells, and identifies miR-222 as a prognostic marker to refine risk stratification within the traditionally favorable-risk t(8;21) AML subgroup. Key PointsO_LILoss of myeloid lineage specific isoform of lncRNA HOTAIRM1 - HOTAIRM1 variant 2, results in de-repression of microRNA miR-222, and contributes to venetoclax resistance in pediatric AML patients harbouring the t(8;21)(q22;q22.1)/RUNX1::RUNX1T1 fusion. C_LIO_LIMicroRNA miR-222 shows potential as a single marker predictor that complements current risk stratification by identifying a subset of pediatric t(8;21) AML patients with poor prognosis. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=156 SRC="FIGDIR/small/663834v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@19a0931org.highwire.dtl.DTLVardef@1d1a51aorg.highwire.dtl.DTLVardef@ae6783org.highwire.dtl.DTLVardef@de78e_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2025

VasoTracker 2: An Open-source Platform for Quantitative Analysis of Vascular Reactivity and Function

VasoTracker 2 is an open-source platform for studying blood vessel dynamics, featuring versatile diameter-tracking software and complementary low-cost hardware components. This system surpasses existing tools through accessible, high-resolution analysis across multiple imaging modalities, enabling comprehensive assessment of vascular dynamics in both real-time and pre-recorded experiments. Advanced algorithms enable multi-point diameter tracking in branched vessels, automated pressure-response protocols, and reliable edge detection. The software can assess vessels imaged by brightfield microscopy, fluorescence imaging, and in ultrasound recordings, supporting diverse applications from isolated vessel studies to in vivo assessment. For ex vivo applications, VasoTracker 2 includes modular open-source hardware components that can be used to create a low-cost pressure myograph system: a confocal-compatible vessel chamber and a programmable pressure controller, VasoMoto. By combining powerful analytical capabilities with an open-access approach, VasoTracker 2 provides free software and low-cost hardware alternatives to commercial systems, democratizing access to advanced vascular research tools for scientists worldwide.

physiology↗

bioRxiv2025

Glutamate and early functional NMDA Receptors promote axonal elongation modulating both actin cytoskeleton dynamics and H2O2 production dependent on Rac1 activity

NMDA Receptors (NMDARs) have essential functions in the nervous system, including neuronal maturation, neurotransmission, synaptic plasticity, learning, and memory. Following membrane depolarization and glutamate activation, NMDARs mediate Ca2+ influx into neurons, activating Ca2+ signaling cascades with key roles in neuronal function. However, no studies have been reported on the roles of glutamate and NMDARs during early neuronal development. Although NMDARs classically act at the postsynaptic membrane, the present results indicate that neurons express functional NMDARs during polarity acquisition and localize them in the axonal compartment early in development; at this stage, cultured neurons spontaneously release glutamate. In addition, pharmacological and genetic experiments for NMDARs loss- and gain-of-function modulated neuronal polarization and axonal elongation antagonistically. An intracellular mechanism involving Ca2+ release from the endoplasmic reticulum, activation of the Rho GTPase Rac1, and actin cytoskeleton rearrangements at the axonal growth cone couples these morphological changes. Moreover, NMDAR activity regulates the physiological intracellular production of hydrogen peroxide (H2O2) via a Rac1/NADPH oxidase complex to support neuronal development. Optogenetic Rac1 activation simultaneously promoted lamellipodia formation and H2O2 production suggesting functional coupling between these seemingly unconnected events. The mechanism presented here involves a dual function for the Rac1 protein that depends on glutamate and NMDAR activity. Based on these findings, we suggest that early physiological and spontaneous glutamate release activates NMDARs to promote early neuronal development before synapse formation, indicating that glutamate is necessary for neurotransmission, early neuronal development, and axonal growth.

cell biology↗

bioRxiv2025

Dynamic balance of H3K9me2 heterochromatin by CoREST-2 and RE-1 in growing neurons

A well-balanced chromatin dynamic is vital for the survival and physiology of all cells, including brain neurons. Heterochromatin, commonly associated with transcriptional silencing, also plays significant roles in maintaining genomic stability and facilitating DNA-repair processes. Notably, the bimethylation of histone H3 at lysine 9 (H3K9me2), a hallmark of repressive heterochromatin, supports the axonal specification of neurons. However, neuronal maintenance of H3K9me2 equilibrium remains understudied. In this work, we unveil a dynamic equilibrium of H3K9me2 regulated by the epigenetic factor CoREST-2 and RE-1 DNA motifs, sustaining axonal and dendritic outgrowth. Using primary cultures of rat hippocampal neurons and a combination of advanced imaging techniques, we observed an enriched nuclear accumulation of CoREST-2 and H3K9me2 along neuronal development. Genetic silencing of CoREST-2 induced axon-dendrite retraction, accompanied by an increase in nuclear levels of H3K9me2. To further investigate heterochromatin structure at the nanoscale, we employed STED nanoscopy and discovered that H3K9me2 is organized into small nanodomains, which were notably enlarged following the suppression of CoREST-2. In contrast, the genetic blockade of RE-1 DNA motifs led to axon-dendrite retraction alongside the disassembly of H3K9me2 nanodomains. These findings highlight that CoREST-2 and RE-1 sites actively shape neuronal H3K9me2 heterochromatin. Moreover, they uncover that maintaining a precise balance of H3K9me2 is essential for the extension of axons and dendrites, underpinning the connectivity and plasticity of brain neurons.

cell biology↗

bioRxiv2024

Human RNase H2 upregulation counteracts oncogene- and chemotherapy-induced replication stress

RNase H2 is a heterotrimeric endoribonuclease that resolves RNA:DNA hybrids and genome-embedded ribonucleotides, which are implicated in DNA replication stress and cancer development. Protein and/or mRNA levels of individual RNase H2 subunits are elevated in some cancers, but little is known about the mechanisms or consequences of RNase H2 upregulation. We report that RNase H2 subunits are upregulated at the protein level in response to replication stress induced by oncogenes and chemotherapy drugs in human cancer and non-cancer cell lines. We show that inducible overexpression of the RNASEH2B subunit increases levels of the active RNase H2 heterotrimer. While causing only subtle changes to gene expression, RNASEH2B overexpression is unexpectedly associated with increased RNA:DNA hybrid levels. RNASEH2B overexpression prevents further increases in RNA:DNA hybrid levels by camptothecin or hydroxyurea and reduces replication fork stalling in presence of these drugs. Surprisingly, RNase H2 levels do not strongly impact survival of chemotherapy treatments but appear to have more subtle effects on genome instability and innate immune signalling. In contrast, increased RNase H2 levels in presence of oncogenic HRAS limit not only RAS-induced replication fork stalling but also cell death. Our findings shed new light on the functions of RNase H2 and suggest that upregulation of RNase H2 may be an important aspect of replication stress responses in cancer.

molecular biology↗

bioRxiv2024

A histomorphological atlas of resected mesothelioma from 3446 whole-slide images discovered by self-supervised learning

1Mesothelioma is a highly lethal and poorly biologically understood disease which presents diagnostic challenges due to its morphological complexity. This study uses self-supervised AI (Artificial Intelligence) to map the histomorphological landscape of the disease. The resulting atlas consists of recurrent patterns identified from 3446 Hematoxylin and Eosin (H&E) stained images scanned from resected tumour slides. These patterns generate highly interpretable predictions, achieving state-of-the-art performance with 0.65 concordance index (c-index) for outcomes and 88% AUC in subtyping. Their clinical relevance is endorsed by comprehensive human pathological assessment. Furthermore, we characterise the molecular underpinnings of these diverse, meaningful, predictive patterns. Our approach both improves diagnosis and deepens our understanding of mesothelioma biology, highlighting the power of this self-learning method in clinical applications and scientific discovery.

pathology↗

bioRxiv2024

The conserved aphid saliva chemosensory protein effector Mp10 targets plant AMSH deubiquitinases at cellular membranes to suppress pattern-triggered immunity

Chemosensory proteins (CSPs) are a conserved family present in insects and other arthropods, recognized for their critical roles in both intra- and interspecies communication. However, the functional mechanisms of these proteins remain largely unexplored. In our previous research, we identified a CSP in aphid saliva, Mp10, from the peach-potato aphid Myzus persicae, which functions as an effector protein modulating host plant immunity. Mp10 suppresses pattern recognition receptor (PRR)-triggered immunity (PTI), the first layer of plant defence, while also inducing effector-triggered immunity (ETI). In this study, we elucidate the molecular mechanisms by which Mp10 suppresses PTI. Our findings reveal that Mp10 interacts with AMSH deubiquitinase enzymes in plants, as shown by yeast two-hybrid, co-immunoprecipitation (co-IP), and FRET-FLIM assays, with these interactions predominantly localized to intracellular membranes. Mp10 was found to modulate the dynamics of membrane-bound PRR receptor kinases in plant cells. Co-IP and mass spectrometry analyses demonstrated that Mp10 and AMSH2 associate with a range of PRR kinases, PRR-associated kinases, and proteins involved in the intracellular trafficking of membrane proteins. Mp10 reduces the accumulation of these kinases at the cell surface by promoting their internalization to internal membranes, thereby dampening PTI. Supporting this, a dominant-negative catalytically inactive variant of AMSH2 also inhibits PTI. Interestingly, Mp10 orthologues from other sap-feeding hemipteran insects exhibit similar immune-suppressive activities, and our findings show that their interaction with plant AMSH proteins is conserved, indicating this immune-suppression mechanism is evolutionarily ancient.

plant biology↗