Biology subjects

Wu, J.

Publications and source records attributed to Wu, J..

At least 379 records · Page 21Linked to original sources

bioRxiv2024

Heterogeneous hybrid immunity against Omicron variant JN.1 at 11 months following breakthrough infection

A highly transmissible SARS-CoV-2 variant JN.1 is rapidly spreading throughout the nation, becoming the predominant strain in China and worldwide. However, the current immunity against the circulating JN.1 at population level has yet to be fully evaluated. We recruited representative cohorts with stratified age groups and diverse combinations of vaccination and/or infection in recent months, and promptly assessed humoral immunity for these subjects predominantly exhibiting hybrid immunity. We report that at 11 months following BA.5-wave breakthrough infection (BTI), these vaccinated individuals generally showed above-the-threshold yet low level of neutralizing activity against JN.1, with slightly greater potency observed in children and adolescents compared to adults and seniors. Meanwhile, XBB/EG.5-wave reinfection post-BTI significantly boosted the neutralizing antibodies against Omicron variants, including JN.1 in both adults (13.4-fold increase) and seniors (24.9-fold increase). To better understand respiratory mucosal protection against JN.1 over an extended period of months post-BTI, we profiled the humoral immunity in bronchoalveolar lavage samples obtained from vaccinated subjects with or without BTI, and revealed increased potency of neutralizing activity against the BA.5 and JN.1 variants in the respiratory mucosa through natural infection. Notably, at 11 months post-BTI, memory B cell responses against prototype and JN.1 were detectable in both blood and respiratory mucosa, displaying distinct memory features in the circulation and airway compartments. XBB/EG.5-wave reinfection drove the expansion of JN.1-specific B cells, along with the back-boosting of B cells responding to the ancestral viral strain, suggesting the involvement of immune imprinting. Together, this study indicates heterogeneous hybrid immunity over 11 months post-BTI, and underscores the vulnerability of individuals, particularly high-risk seniors, to JN.1 breakthrough infection. An additional booster with XBB-containing vaccine may greatly alleviate the onward transmission of immune-evasive SARS-CoV-2 variants.

immunology↗

bioRxiv2024

Dark-based Optical Sectioning assists Background Removal in Fluorescence Microscopy

A fundamental challenge in fluorescence microscopy is the defocused background caused by scattering light, optical aberration, or limited axial resolution. Severe defocus backgrounds will submerge the in-focus information and cause artifacts in the following processing. Here, we leverage a priori knowledge about dark channels of biological structures and dual frequency separation to develop a single-frame defocus removal algorithm. It stably improves the signal-to-background ratio and structural similarity index measure of images by approximately 10-fold, and recovers in-focus signal with 85% accuracy, even when the defocus background is 50 times larger than in-focus information. Our Dark-based optical sectioning approach (Dark sectioning) is fully compatible with various microscopy techniques, such as wide-filed microscopy, polarized microscopy, laser-scanning / spinning-disk confocal microscopy, stimulated emission depletion microscopy, lightsheet microscopy, and light-field microscopy. It also complements reconstruction or processing algorithms such as deconvolution, structure illumination microscopy, and super-resolution optical fluctuation imaging.

bioinformatics↗

bioRxiv2024

Codon Pair-Specific Translation Defects Trigger Ribosome-Associated Quality Control to Avoid Proteotoxic Stress

tRNA modifications tune translation rates and codon optimality, thereby optimizing co-translational protein folding, but how codon optimality defects trigger cellular phenotypes remains unclear. Here, we show that ribosomes stall at specific modification-dependent codon pairs, triggering ribosome collisions and inducing a coordinated and hierarchical response of cellular quality control pathways. Ribosome profiling reveals an unexpected functional diversity for wobble-uridine (U34) modifications during decoding. The same modification can have different effects at the A and P sites. Furthermore, modification-dependent stalling codon pairs induce ribosome collisions, triggering ribosome-associated quality control (RQC) to prevent protein aggregation by degrading aberrant nascent peptides and mRNAs. RQC inactivation stimulates the expression of molecular chaperones to remove protein aggregates. Our results show that loss of tRNA modifications primarily disrupts translation rates of suboptimal codon pairs and reveal the coordinated regulation and adaptability of cellular surveillance systems to ensure efficient and accurate protein synthesis and maintain protein homeostasis.

biochemistry↗

bioRxiv2024

Dynamics of RNA localization to nuclear speckles are connected to splicing efficiency

Nuclear speckles, a type of membraneless nuclear organelle in higher eukaryotic cells, play a vital role in gene expression regulation. Using the reverse transcription-based RNA-binding protein binding sites sequencing (ARTR-seq) method, we study human transcripts associated with nuclear speckles. We identify three gene groups whose transcripts demonstrate different speckle localization properties and dynamics: stably enriched in nuclear speckles, transiently enriched in speckles at the pre-mRNA stage, and not enriched in speckles. Specifically, we find that stably-enriched transcripts contain inefficiently spliced introns. We show that nuclear speckles specifically facilitate splicing of speckle-enriched transcripts. We further reveal RNA sequence features contributing to transcript speckle localization, underscoring a tight interplay between genome organization, RNA cis-elements, and transcript speckle enrichment, and connecting transcript speckle localization with splicing efficiency. Finally, we show that speckles can act as hubs for the regulated retention of introns during cellular stress. Collectively, our data highlight a role of nuclear speckles in both co- and post-transcriptional splicing regulation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=189 SRC="FIGDIR/small/581881v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1a55b13org.highwire.dtl.DTLVardef@fe50baorg.highwire.dtl.DTLVardef@6610fborg.highwire.dtl.DTLVardef@e4df5b_HPS_FORMAT_FIGEXP M_FIG GRAPHICAL ABSTRACT C_FIG

cell biology↗

bioRxiv2024

NINJ1 regulates ferroptosis via xCT antiporter interaction and CoA modulation

Ninjurin-1 (NINJ1), initially identified as a stress-induced protein in neurons, recently emerged as a key mediator of plasma membrane rupture during apoptosis, necrosis, and pyroptosis. However, its involvement in ferroptosis remains unknown. Here, we demonstrate that NINJ1 also plays a crucial role in ferroptosis, but through a distinct mechanism. NINJ1 knockdown significantly protected cancer cells against ferroptosis induced by xCT inhibitors but no other classes of ferroptosis-inducing compounds (FINs). Glycine, known to inhibit canonical NINJ1-mediated membrane rupture in other cell deaths, had no impact on ferroptosis. A compound screen revealed that NINJ1-mediated ferroptosis protection can be abolished by pantothenate kinase inhibitor (PANKi), buthionine sulfoximine (BSO), and diethylmaleate (DEM). These results suggest that this ferroptosis protection is mediated via Coenzyme A (CoA) and glutathione (GSH), both of which were found to be elevated upon NINJ1 knockdown. Furthermore, we discovered that NINJ1 interacts with the xCT antiporter, which is responsible for cystine uptake for the biosynthesis of CoA and GSH. The removal of NINJ1 increased xCT levels and stability, enhanced cystine uptake, and contributed to elevated CoA and GSH levels, collectively contributing to ferroptosis protection. These findings reveal that NINJ1 regulates ferroptosis via a non-canonical mechanism, distinct from other regulated cell deaths. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/581432v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@9fa073org.highwire.dtl.DTLVardef@1df0137org.highwire.dtl.DTLVardef@1c8e8cborg.highwire.dtl.DTLVardef@12b76b3_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2024

Brain preparedness: The cortisol awakening response proacts dynamic organization of large-scale brain networks across emotional and executive functions

Emotion and cognition involve an intricate crosstalk of neural and endocrine systems that support allostatic processes for maintenance of dynamic equilibrium and rapid adaptation for upcoming challenges. As a hallmark of human endocrine activity, the cortisol awakening response (CAR) is recognized to play a critical role in modulating emotional and executive functions. Yet, the underlying mechanisms of such effects remain elusive. By leveraging pharmacological neuroimaging technique and Hidden Markov Modeling of brain state dynamics, we show that the CAR proactively modulates rapid reconfigurations (state) of large-scale brain networks across multi-task demands. Behaviorally, suppression of CAR proactively and selectively impaired accuracy for emotional discrimination task but not for working memory (WM). In parallel, suppressed CAR led to a decrease in the occurrence rate of brain state dominant to emotional processing, but an increase in brain state linking to executive control under high WM demand. Further energy-based analyses revealed an increase in transition frequency and sequence complexity along with an increased entropy during emotional tasks when suppressed CAR, suggesting a decreased energy supply. Moreover, an increased transition frequency was observed when shifting from neutral to emotional conditions, but an opposite pattern during WM task, with n decreased transition frequency shifts from low to high-executive demands. Our findings establish a causal link between CAR and dynamic allocation of neural resources for emotional and executive functions, suggesting a cognitive neuroendocrine account for CAR-mediated proactive effects and human allostasis.

neuroscience↗

bioRxiv2024

Canonical AREs are tumor suppressive regulatory elements in the prostate

The androgen receptor (AR) is the central determinant of prostate tissue identity and differentiation, controlling normal, growth-suppressive prostate-specific gene expression1. It is also a key driver of prostate tumorigenesis, becoming "hijacked" to drive oncogenic transcription2-5. However, the regulatory elements determining the execution of the growth suppressive AR transcriptional program, and whether this can be reactivated in prostate cancer (PCa) cells remains unclear. Canonical androgen response element (ARE) motifs are the classic DNA binding element for AR6. Here, we used a genome-wide strategy to modulate regulatory elements containing AREs to define distinct AR transcriptional programs. We find that activation of these AREs is specifically associated with differentiation and growth suppressive transcription, and this can be reactivated to cause death in AR+ PCa cells. In contrast, repression of AREs is well tolerated by PCa cells, but deleterious to normal prostate cells. Finally, gene expression signatures driven by ARE activity are associated with improved prognosis and luminal phenotypes in human PCa patients. This study demonstrates that canonical AREs are responsible for a normal, growth-suppressive, lineage-specific transcriptional program, that this can be reengaged in PCa cells for potential therapeutic benefit, and genes controlled by this mechanism are clinically relevant in human PCa patients.

cancer biology↗

bioRxiv2024

GhCPK28 negatively regulates the immune response by phosphorylating GhTIFY3b

The soil-borne fungus Verticillium dahliae (V. dahliae) seriously inhibits cotton (Gossypium hirsutum) growth and productivity. The immune system of cotton against this pathogen is largely unknown. Here we investigated the involvement of Ca2+-dependent protein kinases (CPKs) in this immunity. One CPK coding gene GhCPK28 had reduced expression after infection by V. dahliae in cotton. Knocking down of the GhCPK28 by virus induced gene silencing led to enhanced resistance to V. dahliae which is accompanied by a higher ROS accumulation and systemic acquired response. GhCPK28 was found to phosphorylate a TIFY family protein GhTIFY3b and reduce its stability. Silencing GhTIFY3b increased the susceptibility of cotton to V. dahliae. Together, this study indicate that GhCPK28 is a negative regulator of defense against V. dahliae infection and the GhTIFY3b might be a target protein of its activity. It sheds light on the immune system against V. dahliae and provides candidate genes for improving resistance against Verticillium wilt in cotton.

plant biology↗

bioRxiv2024

Transcriptomic analysis of the human habenula in schizophrenia

Pathophysiology of many neuropsychiatric disorders, including schizophrenia (SCZD), is linked to habenula (Hb) function. While pharmacotherapies and deep brain stimulation targeting the Hb are emerging as promising therapeutic treatments, little is known about the cell type-specific transcriptomic organization of the human Hb or how it is altered in SCZD. Here we define the molecular neuroanatomy of the human Hb and identify transcriptomic changes in individuals with SCZD compared to neurotypical controls. Utilizing Hb-enriched postmortem human brain tissue, we performed single nucleus RNA-sequencing (snRNA-seq; n=7 neurotypical donors) and identified 17 molecularly defined Hb cell types across 16,437 nuclei, including 3 medial and 7 lateral Hb populations, several of which were conserved between rodents and humans. Single molecule fluorescent in situ hybridization (smFISH; n=3 neurotypical donors) validated snRNA-seq Hb cell types and mapped their spatial locations. Bulk RNA-sequencing and cell type deconvolution in Hb-enriched tissue from 35 individuals with SCZD and 33 neurotypical controls yielded 45 SCZD-associated differentially expressed genes (DEGs, FDR < 0.05), with 32 (71%) unique to Hb-enriched tissue. eQTL analysis identified 717 independent SNP-gene pairs (FDR < 0.05), where either the SNP is a SCZD risk variant (16 pairs) or the gene is a SCZD DEG (7 pairs). eQTL and SCZD risk colocalization analysis identified 16 colocalized genes. These results identify topographically organized cell types with distinct molecular signatures in the human Hb and demonstrate unique genetic changes associated with SCZD, thereby providing novel molecular insights into the role of Hb in neuropsychiatric disorders. One Sentence SummaryTranscriptomic analysis of the human habenula and identification of molecular changes associated with schizophrenia risk and illness state.

neuroscience↗

bioRxiv2024

TASOR expression in naive embryonic stem cells safeguards their developmental potential

The seamless transition through stages of pluripotency relies on a delicate balance between transcription factor networks and epigenetic silencing mechanisms that ensure proper regulation of the developmental program, critical for normal development. Here, we uncover the pivotal role of the transgene activation suppressor (TASOR), a component of the human silencing hub (HUSH) complex, in sustaining cell viability during the transition from naive to primed pluripotency, despite its rapid downregulation during this transition. Loss of TASOR in naive cells triggers replication stress, disrupts H3K9me3 heterochromatin formation, and compromise the transcriptional and post-transcriptional silencing of LINE-1 (L1) transposable elements (TEs), with these effects become more pronounced in primed cells. Remarkably, the survival of Tasor-knockout cells during naive to primed transition can be restored through the inhibition of cysteine-aspartic acid protease (Caspase) or deletion of mitochondrial antiviral signaling protein (MAVS). This suggests that unscheduled L1 expression activates an innate immune response, leading to programmed cell death, specifically in cells exiting naive pluripotency. Additionally, we propose that HUSH-promoted H3K9me3 in naive PSCs sets the stage for ensuing DNA methylation in primed cells, establishing long-term silencing during differentiation. Our findings shed insights on the crucial impact of epigenetic programs established in early developmental stages on subsequent phases, underscoring their significance in the developmental process.

developmental biology↗

bioRxiv2024

A Systematically Optimized Miniaturized Mesoscope (SOMM) for large-scale calcium imaging in freely moving mice

Understanding how neuronal dynamics gives rise to ethologically relevant behavior requires recording of neuronal population activity via technologies that are compatible with unconstrained animal behavior. However, realizations of cellular resolution head-mounted microscopes for mice have been based on conventional microscope designs that feature various forms of ad-hoc miniaturization and weight reduction measures necessary for compatibility with the weight-limits for free animal behavior. As a result, they have typically remained limited to a small field of view (FOV) or low resolution, a shallow depth range and often remain susceptible to motion-induced artifacts. Here, we present a systematically optimized miniaturized mesoscope (SOMM), a widefield, head-mounted fluorescent mesoscope based on a principled optimization approach that allows for mesoscale, cellular resolution imaging of neuroactivity while offering robustness against motion-induced artifacts. This is achieved by co-optimization of a compact diffractive optical element and the associated computational algorithm under form-factor and weight constraints while maximizing the obtainable FOV, depth of field (DOF), and resolution. SOMM enables recordings of neuronal population activity at up to 16 Hz within a FOV of 3.6 x 3.6 mm2 in the cortex of freely moving mice while featuring 4-{micro}m resolution, a DOF of 300 {micro}m at a weight of less than 2.5 g. We show SOMMs performance of recording large-scale neuronal population activity during social interactions, during conditioning-type experiments and by investigating neurovascular coupling using dual-color imaging.

neuroscience↗

bioRxiv2024

Fast and accurate modeling and design of antibody-antigen complex using tFold

Accurate prediction of antibody-antigen complex structures holds significant potential for advancing biomedical research and the design of therapeutic antibodies. Currently, structure prediction for protein monomers has achieved considerable success, and promising progress has been made in extending this achievement to the prediction of protein complexes. However, despite these advancements, fast and accurate prediction of antibody-antigen complex structures remains a challenging and unresolved issue. Existing end-to-end prediction methods, which rely on homology and templates, exhibit sub-optimal accuracy due to the absence of co-evolutionary constraints. Meanwhile, conventional docking-based methods face difficulties in identifying the contact interface between the antigen and antibody and require known structures of individual components as inputs. In this study, we present a fully end-to-end approach for three-dimensional (3D) atomic-level structure predictions of antibodies and antibody-antigen complexes, referred to as tFold-Ab and tFold-Ag, respectively. tFold leverages a large protein language model to extract both intra-chain and inter-chain residue-residue contact information, as well as evolutionary relationships, avoiding the time-consuming multiple sequence alignment (MSA) search. Combined with specially designed modules such as the AI-driven flexible docking module, it achieves superior performance and significantly enhanced speed in predicting both antibody (1.6% RMSD reduction in the CDR-H3 region, thousand times faster) and antibody-antigen complex structures (37% increase in DockQ score, over 10 times faster), compared to AlphaFold-Multimer. Given the performance and speed advantages, we further extend the capability of tFold for structure-based virtual screening of binding antibodies, as well as de novo co-design of both structure and sequence for therapeutic antibodies. The experiment results demonstrate the potential of tFold as a high-throughput tool to enhance processes involved in these tasks. To facilitate public access, we release code and offer a web service for antibody and antigen-antibody complex structure prediction, which is available at https://drug.ai.tencent.com/en.

bioinformatics↗

bioRxiv2024

Neuronal potassium channel activity triggers initiation of mRNA translation through binding of translation regulators

Neuronal activity stimulates mRNA translation crucial for learning and development. While FMRP (Fragile X Mental Retardation Protein) and CYFIP1 (Cytoplasmic FMR1 Interacting Protein 1) regulate translation, the mechanism linking translation to neuronal activity is not understood. We now find that translation is stimulated when FMRP and CYFIP1 translocate to the potassium channel Slack (KCNT1, Slo2.2). When Slack is activated, both factors are released from eIF4E (Eukaryotic Initiation Factor 4E), where they normally inhibit translation initiation. A constitutively active Slack mutation and pharmacological stimulation of the wild-type channel both increase binding of FMRP and CYFIP1 to the channel, enhancing the translation of a reporter for {beta}-actin mRNA in cell lines and the synthesis of {beta}-actin in neuronal dendrites. Slack activity-dependent translation is abolished when both FMRP and CYFIP1 expression are suppressed. The effects of Slack mutations on activity-dependent translation may explain the severe intellectual disability produced by these mutations in humans. HIGHLIGHTSO_LIActivation of Slack channels triggers translocation of the FMRP/CYFIP1 complex C_LIO_LISlack channel activation regulates translation initiation of a {beta}-actin reporter construct C_LIO_LIA Slack gain-of-function mutation increases translation of {beta}-actin reporter construct and endogenous cortical {beta}-actin C_LIO_LIFMRP and CYFIP1 are required for Slack activity-dependent translation C_LI IN BRIEFMalone et al. show that the activation of Slack channels triggers translocation of the FMRP/CYFIP1 complex from the translation initiation factor eIF4E to the channel. This translocation releases eIF4E and stimulates mRNA translation of a reporter for {beta}-actin and cortical {beta}-actin mRNA, elucidating the mechanism that connects neuronal activity with translational regulation.

neuroscience↗

bioRxiv2024

The mitochondrial thiolase ACAT1 regulates monocyte/macrophage type I interferon via epigenetic control.

Lipid-derived acetyl-CoA is shown to be the major carbon source for histone acetylation. However, there is no direct evidence demonstrating lipid metabolic pathway contribututions to this process. Mitochondrial acetyl-CoA acetyltransferase 1 (ACAT1) catalyzes the final step of {beta}-oxidation, the aerobic process catabolizing fatty acids (FA) into acetyl-CoA. To investigate this in the context of immunometabolism, we generated macrophage cell line lacking ACAT1. 13C-carbon tracing combined with mass spectrometry confirmed incorporation of FA-derived carbons into histone H3 and this incorporation was reduced in ACAT1 KO macrophage cells. RNA-seq identified a subset of genes downregulated in ACAT1 KO cells including STAT1/2 and interferon stimulated genes (ISGs). CHIP analysis demonstrated reduced acetyl-H3 binding to STAT1 promoter/enhancer regions. Increasing histone acetylation rescued STAT1/2 expression in ACAT1 KO cells. Concomitantly, ligand triggered IFN{beta} release was blunted in ACAT1 KO cells and rescued by reconstitution of ACAT1. Furthermore, ACAT1 promotes FA-mediated histone acetylation in an acetylcarnitine shuttle-dependent manner. In patients with obesity, levels of ACAT1 and histone acetylation are abnormally elevated. Thus, our study identified a novel link between ACAT1 mediated FA metabolism and epigenetic modification on STAT1/2 that uncovers a regulatory role of lipid metabolism in innate immune signaling and opens novel avenues for interventions in human diseases such as obesity.

immunology↗

bioRxiv2024

Global heterogeneity of latitudinal patterns in herbivory between native and exotic plants

Latitudinal gradient of herbivory that differs between native and exotic plants has been an open issue. It is expected that a latitudinal gradient of herbivory will be evident for native plants; this gradient in exotic plants may lag behind native plants in terms of co-evolution with local abiotic and biotic factors in introduced area. Our study aims to elucidate the difference in latitudinal gradient of herbivory between native and exotic plants globally, while exploring the underlying mechanisms driving the latitudinal gradient of herbivory with biotic and abiotic factors. To achieve this, we analyzed herbivory data from 94 studies and calculated 862 herbivory effect sizes (zr) to quantitatively characterize the intensity of latitudinal herbivory gradient. For each herbivory data, we matched the corresponding plant identity (native/exotic), herbivore feeding guilds and climate data to reveal the contribution of these factors to zr. Our findings demonstrate a significant decrease in the latitudinal gradients of with increasing latitude for native plants, a pattern not observed for exotic plants. The heterogeneity in latitudinal gradients of herbivory between native and exotic plants is mediated by herbivore feeding guilds. There is a significant influence of climatic factors on the latitudinal gradient of herbivory for native plants, but not for exotic plants. Overall, our results underscore a general heterogeneity in global macroecological herbivory patterns between native and exotic plants, and highlight the role of biotic and abiotic factors in explaining these global-scale differences.

ecology↗

bioRxiv2024

The eyes have it: Inter-subject correlations of pupillary responses for audience response measurement in VR

The eye is the vanguard of the reception process, constituting the point where visual information arrives and is transformed into neural signals. While we view dynamic media contents, a fine-tuned interplay of mechanisms causes our pupils to dilate and constrict over time - and putatively similarly across audience members exposed to the same messages. Research that once pioneered pupillometry did actually use dynamic media as stimuli, but this trend then stalled, and pupillometry remained underdeveloped in the study of naturalistic media stimuli. Here, we introduce a VR-based approach to capture audience members pupillary responses during media consumption and suggest an innovative analytic framework. Specifically, we expose audiences to a set of 30 different video messages and compute the cross-receiver similarity of pupillometric responses. Based on this data, we identify the specific video an individual is watching. Our results show that this pupil-pulse-tracking enables highly accurate decoding of video identity. Moreover, we demonstrate that the decoding is relatively robust to manipulations of video size and distractor presence. Finally, we examine the relationship between pupillary responses and subsequent memory. Theoretical implications for objectively quantifying exposure and states of audience engagement are discussed. Practically, we anticipate that this pupillary audience response measurement approach could find application in media measurement across contexts, ranging from traditional screen-based media (commercials, movies) to social media (e.g., TikTok and YouTube), and to next-generation virtual media environments (e.g., Metaverse, gaming).

physiology↗

bioRxiv2024

Bypassing PELO-mediated ATPase activation of NLR is a common pathogenic cause of NLR-associated autoinflammatory diseases

Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) constitute the largest family of pattern recognition receptors. These receptors are master regulators of innate immunity. Recently, PELO-driven ATPase activation of NLRs was demonstrated as a critical step in NLR activation. Linkage studies in human with various inherited autoinflammatory conditions have revealed an extensive array of mutations and polymorphisms within NLRs. However, the precise mechanisms by which genetic variations in NLR genes contribute to disease onset remain largely elusive. Here we comprehensively analyze dozens of naturally occurring mutations across multiple human NLRs, and demonstrate that NLRs harboring pathogenic mutations in their NACHT domain--not those with non-pathogenic variants--exhibit spontaneous PELO-independent ATPase activation. This aberrant activation triggers corresponding NLR to mediate inflammatory responses. Thus, bypassing the PELO-checkpoint for ATPase activation is a major disease-causing mechanism underlying NLR mutations. Furthermore, quantifying this aberrant ATPase activation could serve as an assessment tool for classifying the pathogenesis of NLR-associated diseases.

immunology↗

bioRxiv2024

PbrSYP71 regulates ER accumulation by interacting with actin during pollen tube growth in Pyrus

The uneven distribution of endoplasmic reticulum (ER) underlies the rapid polar growth of pollen tubes. However, the mechanism governing ER distribution remains elusive. In this study, we have identified a pollen tube-specific syntaxin protein, PbrSYP71. Our findings reveal that both overexpression and knocking down of PbrSYP71 inhibited pollen tube growth. Subcellular localization analysis demonstrates that PbrSYP71 anchors to the ER via its transmembrane structure. Overexpression of PbrSYP71 leads to clustered ER distribution in the pollen tube, while knocking down of PbrSYP71 abolishes the uneven ER distribution. Remarkably, transient overexpression of PbrSYP71{Delta}ABD, lacking the actin binding domain (ABD) of PbrSYP71, has no impact on ER distribution or pollen tube growth. Further investigation indicates that ABD is positioned on F-actin in the pollen tube and has a direct interaction with F-actin. PbrSYP71 assists the ER in moving towards the apex of pollen tube, with ABD displaying autonomous mobility. Our study elucidates that PbrSYP71 maintains uneven distribution of the ER by tethering ER to F-actin, facilitating ER movement towards the pollen tube apex for pear pollen tube elongation. These insights shed light on the mechanisms governing ER distribution in polarized cell growth.

cell biology↗