Biology subjects

Xu, S.-L.

Publications and source records attributed to Xu, S.-L..

At least 19 recordsLinked to original sources

bioRxiv2026

Ca2+-activated CKL3 phosphorylates nucleoporin 58 to reprogram nuclear transport and execute effector-triggered immunity

Recognition of pathogen effectors by nucleotide-binding leucine-rich repeat receptors (NLRs) activates effector-triggered immunity (ETI) in plants through resistosome formation, which generates a sustained cytosolic Ca2+ influx and ultimately leads to programmed cell death (PCD) at infection sites and resistance. However, the mechanisms linking Ca2+ influx to ETI execution remains a major knowledge gap. Using TurboID proximity labeling with the central transport channel nucleoporin 58 (Nup58) as a probe, we show that, instead of deregulation, ETI induction restricts general nuclear trafficking while selectively enhancing nuclear import of defense-related proteins. This switch is driven by elevated cytosolic Ca2+, which binds to the conserved Asp-149 in CASEIN KINASE 1-LIKE 3 (CKL3), promoting its interaction with and phosphorylation of Nup58 at Ser-149, thereby altering nuclear pore selectivity. This study identifies CKL3 and Nup58 as key regulators of ETI by establishing a mechanistic link from resistosome-mediated Ca2+ influx to nuclear transport reprogramming and immune execution.

plant biology↗

bioRxiv2026

CDK8 phosphorylation of DELLA limits Mediator recruitment in gibberellin signaling

Gibberellin (GA) promotes plant growth primarily by triggering degradation of DELLA transcription regulators, yet how DELLA activity is fine-tuned dynamically by phosphorylation independently of proteolysis remains poorly understood. Here we show that the CDK8 kinase module of the Mediator complex attenuates activity of the Arabidopsis DELLA protein RGA by modulating coactivator recruitment. Using TurboID-based proximity labeling, biochemical and genetic analyses, we identify CDK8 as an in-planta kinase that phosphorylates RGA at Ser170 within its disordered PolyS/T region. This phosphorylation does not affect RGA stability, localization or interactions with transcription factors or histone H2A, but selectively weakens RGA association with the Mediator subunit MED15, thereby reducing DELLA-dependent transcription activation. Consistently, cdk8 mutants show impaired GA-responses and delayed developmental phase transitions that are partially rescued by loss of DELLA function. Our findings uncover a phosphorylation-dependent mechanism by which the Mediator kinase module fine-tunes hormone-responsive transcription through selective control of DELLA-coactivator interactions.

plant biology↗

bioRxiv2026

Genetic code expansion enables plant-directed control of bacterial activity

Programmable control of microbial gene expression by plant hosts could enable a new generation of precision agricultural biotechnology. Here, using O-methyl-L-tyrosine (OMY) as a model compound, we establish non-canonical amino acids (ncAAs) as a tool for plant-based control of associated microbial activity. We use genetic code expansion to engineer OMY-dependent control of protein synthesis in the soil bacterium Bacillus subtilis. Then, we engineer agronomically diverse plants, including Arabidopsis, tomato and poplar, to biosynthesize OMY. We show that plant-derived OMY can stimulate gene expression in both model and wild soil bacteria while also demonstrating that inducible and tissue-specific expression of a single biosynthetic enzyme by the plant enables on-demand control over microbial activity. This work establishes ncAAs as a tool for programming plant-microbe partnerships.

synthetic biology↗

bioRxiv2026

Linking sugar sensing to immunity in plants via O-glycosylation

Interaction with microbes can reprogram metabolism and alter nutrient availability in plant cells. How metabolic changes modulate immune responses remains unknown. Here, we show that sugar-sensing O-glycosylation of immune-signaling kinases mediates metabolic regulation of immunity. Under sugar-replete conditions, the MAP kinase kinases (MKK4 and MKK5), key components of pattern-triggered immunity (PTI), are glycosylated with O-GlcNAc and O-fucose on their activation loops, blocking their phosphorylation by upstream kinases and thereby restricting PTI. Pathogen infection or sugar starvation reduces O-glycosylation of MKK4/5 and enhances immune signaling; these effects are reversed by GDP-fucose treatment, demonstrating that reduced sugar availability decreases O-fucosylation and enhances immune signaling in infected cells. Chemical inhibition of O-fucosylation enhances immunity and pathogen resistance in both Arabidopsis and tomato. Our findings establish O-glycosylation of MKKs as a metabolic rheostat that fine-tunes immune responses according to sugar availability during plant-microbe interactions, providing a new strategy for improving crop health.

plant biology↗

bioRxiv2026

FoTO1 orchestrates Taxol biosynthesis through catalytic and non-catalytic mechanisms

Taxol is a blockbuster chemotherapeutic derived from the Pacific Yew tree. Recent work in our group has identified a complete pathway to baccatin III, a key intermediate, that hinges on a novel accessory protein, Facilitator of Taxane Oxidation (FoTO1). This protein dramatically improves yield and alters enzyme product profiles when reconstituting the Taxol pathway in N. benthamiana. FoTO1 has been shown to act early in the biosynthetic pathway improving the yields of product generated by the combination of a plastidial diterpene synthase (taxadiene synthase) and an endoplasmic reticulum (ER) localized cytochrome P450 (T5-alpha-hydroxylase). Here, we show that FoTO1 is an enzyme capable of converting taxadiene-(4),5-epoxide, the likely product of T5H oxidation, into taxadien-5-ol. FoTO1 is also functional in yeast, resolving a key bottleneck for development of a bioproduction route to Taxol in this host. Targeted mutagenesis of key catalytic residues in FoTO1 abrogates function in vitro but not in planta, suggesting non-catalytic contributions of FoTO1 to the taxane pathway. A combination of proximity labelling, bimolecular fluorescence complementation assays, and co-immunoprecipitation studies revealed that FoTO1 interacts with and organizes various P450s in the Taxol pathway. These approaches highlight the importance of both FoTO1s catalytic and non-catalytic functions in improving yields in the early Taxol pathway. Beyond Taxol biosynthesis, FoTO1 boosts yields for diverse diterpene pathways from across phylogeny, suggesting a general role of this protein class in mediating metabolism across the plastid and ER in plants.

biochemistry↗

bioRxiv2026

Proteomic Analysis Reveals Widespread Regulation of Substrate Protein Abundance by O-fucosylation and O-GlcNAcylation

O-glycosylation of nucleocytosolic proteins by the Arabidopsis enzymes SPINDLY (SPY; O-fucosyltransferase) and SECRET AGENT (SEC; O-GlcNAc transferase) is essential for plant growth and development, yet the scope of their substrates and regulatory impact remains poorly defined. Here, we combined TurboID-based proximity labeling with quantitative proteomics to systematically map the SPY interactome and determine how SPY- and SEC-dependent modifications influence protein abundance. A functional SPY-TD enriched 221 proxiome proteins, including 80 known O-fucosylated substrates and 141 new interactors. The SPY-TD proxiome is enriched in nuclear pore components, chromatin regulators, transcription factors, and RNA-processing proteins. Integration with O-fucose and O-GlcNAc datasets yielded a comprehensive Arabidopsis SPY/SEC (At-S/S) protein list of 886 candidates. We quantified proteome-wide changes in spy single mutants and inducible spy sec double mutants. Loss of SPY alone caused selective stabilization or destabilization of targets, whereas combined SPY/SEC depletion triggered widespread, synergistic protein abundance changes, particularly affecting nucleoporins, transcriptional regulators, and RNA-binding proteins. Integration with ubiquitination datasets revealed extensive overlap, supporting potential crosstalk between O-fucosylation, O-GlcNAcylation, and ubiquitin-mediated protein turnover. Together, our study establishes proximity labeling as a powerful strategy to define plant O-glycosylation networks and reveals dual, context-dependent roles of SPY and SEC in controlling protein homeostasis and stress-responsive pathways.

systems biology↗

bioRxiv2025

Brassinosteroids promote sugar synthesis by inhibiting BIN2 phosphorylation of phosphoenolpyruvate carboxykinase

Sugar is both an essential energy source and the major substrate for cell wall biosynthesis during plant growth, yet how growth-promoting hormones regulate sugar synthesis remains unclear. Here, we show that the brassinosteroids (BRs) promote gluconeogenic and photosynthetic sugar synthesis by activating phosphoenolpyruvate carboxykinase (PCK), which catalyzes the conversion of oxaloacetate to phosphoenolpyruvate, a central step in primary metabolism. Arabidopsis BR-deficient mutants display reduced PCK1 activity and elevated phosphorylation at conserved Ser-62 and Thr-66 residues. BR treatment induces PCK1 dephosphorylation and activation, whereas the GSK3-like kinase BIN2 phosphorylates these sites, altering quaternary structure and inhibiting PCK1. Phospho-blocking mutations of Ser-62/Thr-66 confer BR-independent PCK1 activity and enhance seedling growth, while phosphomimetic mutations reduce PCK1 activity and impair seedling growth and establishment. BR also promotes PCK dephosphorylation and activation in photosynthetic leaves of maize and sorghum. Our study demonstrates that BR regulates primary metabolism via GSK3/BIN2-mediated phosphorylation of PCK, thereby promoting gluconeogenesis and photosynthesis.

plant biology↗

bioRxiv2025

Antagonistic interactions between CLAVATA receptors shape maize ear development

Meristem activity is controlled by the CLAVATA (CLV) signaling pathway, which involves a suite of leucine rich receptor (LRR) receptors, receptor-like proteins and CLV- EMBRYO SURROUNDING REGION (CLE) peptide ligands. FASCIATED EAR 3 (FEA3) is a leucine rich receptor (LRR) receptor-like protein important for meristem maintenance in maize, and acts independently of canonical CLV receptors. Weak alleles of fea3 can increase yield-related traits in maize, so understanding how FEA3 controls inflorescence development can maximize its potential as a crop improvement target. To identify FEA3s interaction network, we used TurboID-based proximity labeling in maize meristems, and identified a putative co-receptor, BARELY ANY MERISTEM 1D (BAM1D). BAM1D and FEA3 proximity labeling proteomes shared over 100 proteins, including many signaling proteins, suggesting they feed into a common signaling pathway. fea3 was epistatic to bam1d in the control of IM size, supporting the idea that FEA3 and BAM1D interact physically. However, fea3 and bam1d act antagonistically, because fea3 mutants had larger inflorescence meristems (IMs), whereas bam1d mutants produced smaller IMs. Together, this study demonstrates how in vivo TurboID-based proximity labeling clarifies complex genetic interactions between CLV receptors and expands our knowledge of downstream signaling components of CLV signaling pathways, which are largely uncharacterized. Our findings support the notion that multiple, partially overlapping CLV receptor complexes coordinately control meristem maintenance.

plant biology↗

bioRxiv2025

Cellulose Synthase Complex and Remorin Nanodomains Mediate Stress Resilience Through Cell Wall-Plasma Membrane Attachments

HighlightsO_LIThe plasma membrane forms attachments to the plant cell wall that are revealed by hyperosmotic shock and correlate with tolerance to stress. C_LIO_LICellulose Synthase Complex (CSC) clusters and REMORIN (REM) nanodomains localize to cell wall-plasma membrane attachment sites. C_LIO_LICSC density at the plasma membrane determines the extent of cell wall-plasma membrane attachment under hyperosmotic stress. C_LIO_LIREMs rapidly form nanodomains under hyperosmotic stress and are associated with SHOU4/4L, CSC exocytosis inhibitors that limit CSC density at the plasma membrane. C_LI The outer cell surface of an organism is the frontline for detecting and responding to environmental stimuli. In plants, this interface consists of the plasma membrane that lies beneath the cell wall and remains associated with it through attachment sites. These wall-membrane attachments become evident upon hyperosmotic shock, when severe water loss causes the membrane to retract from the wall. Despite their long-standing observation, the molecular identity and function of these attachments remain poorly understood. Here, we identified two mechanisms governing wall-membrane attachments: one dependent on the Cellulose Synthase Complex (CSC), whose density at the plasma membrane positively correlates with resistance to hyperosmotic stress, and the other on REMORIN (REM), which acts antagonistically to the CSC mechanism. Using proximity-labeling proteomics, we identified SHOU4/4L as REM-associated proteins that mediate this antagonism. Together, our findings reveal how wall-membrane attachments are patterned to mediate plant cell resilience under water stress.

plant biology↗

bioRxiv2025

Reconstitution of lamin assembly on nuclear pore complex-containing membranes

Intermediate filaments called lamins line the metazoan nuclear envelope and organize the nucleus and genome. Unlike actin and microtubules, purified intermediate filament proteins assemble into non-physiological structures, making it difficult to connect lamin functions to their assembly and regulation. To overcome this challenge and shed light on physiological lamin assembly mechanisms, we conducted biochemical studies of lamin-B3 endogenously present in Xenopus laevis egg extracts, which recapitulate physiological context. When we mimicked nucleoplasm conditions, which would support assembly of lamin filaments in in-tact cells, lamin-B3 assembled into higher-order structures resembling filamentous meshworks without accompanying nuclear assembly. This ectopic lamin assembly occurs on nuclear pore complex-containing membranes, but does not apparently recruit known nuclear lamina components, demonstrating that a lamin assembly process is partially separable from the rest of the nuclear lamina and nucleus. This assembly assay in the physiological context of cellular components opens the door to further dissecting nuclear lamina function in nuclear organization. SummaryMimicking nucleoplasm conditions in Xenopus laevis egg extracts triggers a lamin assembly reaction independent of nucleus assembly, giving new insights into potential lamin assembly mechanisms.

cell biology↗

bioRxiv2025

Mitotic entry is controlled by the plant-specific phosphatase BSL1 and cyclin-dependent kinase B

Cell cycle regulation is well understood in opisthokonts (fungi and metazoans) but not in plants and Apicomplexa, as some cell cycle regulators are not conserved1-3. In opisthokonts, cell cycle progression requires dephosphorylation of cyclin-dependent kinase (CDK) by the CDC25 phosphatase4. Plants have no CDC25, and thus their mechanisms of cell cycle regulation remain elusive1,5,6. Here, we show that the BSL1 phosphatase dephosphorylates CDKB1 to promote mitotic entry in Chlamydomonas. Mutations of BSL1 or CDKB1 block mitotic entry after DNA replication. BSL1 shows dynamic localization through the cell cycle at the basal bodies, spindle poles, and cleavage furrow. CDKB1 is hyperphosphorylated at T14 and Y15 residues in the bsl1 mutant and in wild-type cells treated with DNA replication inhibitors. BSL1 binds to CDKB1 and dephosphorylates CDKB1 pT14/pY15 in vitro. Phospho-mimicking mutations of T14/Y15 inactivate CDKB1 function, whereas phospho-blocking mutations cause sensitivity to DNA replication inhibitors, which delay cytokinesis in wild-type cells more than cells expressing unphosphorylatable mutant CDKB1. These results indicate that CDKB1 T14/Y15 is phosphorylated to block mitotic entry before DNA replication is complete, and BSL1 dephosphorylates CDKB1 to promote mitosis. Our study demonstrates that BSL1, a phosphatase conserved in plants and Apicomplexa but absent in fungi and animals, is a CDKB1-activating mitosis-promoting factor that has evolved additional signaling functions in receptor kinase pathways in higher plants. One-Sentence SummaryBSL1 is a mitosis-promoting phosphatase that activates CDKB1 in plants.

plant biology↗

bioRxiv2025

Mapping Architecture of Protein complexes in Arabidopsis using XL-MS

Capturing molecular machines in action is essential for understanding protein complex architecture, cellular regulation, and gene function. Here, we present a large-scale structural proteomics resource for Arabidopsis thaliana generated using an optimized cross-linking mass spectrometry (XL-MS) workflow. Using the trifunctional cross-linker PhoX, whose phosphonic acid moiety enables immobilized metal affinity chromatography (IMAC)-based enrichment, we selectively enriched cross-linked peptides from whole-cell lysates, chloroplasts, and nuclei. Analysis with pLink 3.2 identified 52,944 unique cross-linked peptide pairs, corresponding to 37,531 residue-level contacts across 5,064 proteins. These data define 3,083 protein-protein interactions, including 2,385 heteromeric and 698 homomultimeric interactions. Comparison with the STRING database showed that 676 interactions are supported by STRING scores [≥]0.9. Structural mapping to Protein Data Bank (PDB) and AlphaFold models showed that most cross-links were within the expected 35 [A] distance constraint. The dataset further enabled the analysis of protein connectivity and complex topology across diverse molecular assemblies, including the Rubisco holoenzyme, chloroplast 70S ribosome, photosystem complexes, and the cytosolic 80S ribosome together with associated biogenesis and regulatory factors. We also identified histone-associated complexes, including interactions involving an O-acyltransferase. By providing residue-level structural constraints for a substantial portion of the Arabidopsis proteome, this study provides a resource for exploring plant molecular machines and their spatial organization. Significance StatementUnderstanding how proteins interact within living cells is essential to deciphering cellular architecture and function. However, capturing native protein-protein interactions (PPIs) on a global scale has proven technically challenging. Here, we present a proteome-wide cross-linking mass spectrometry (XL-MS) platform that can systematically map direct PPIs in plant cells without requiring transgenic manipulation. This approach identifies thousands of interactions spanning major subcellular compartments and characterizes the in situ organization of critical protein assemblies, such as photosystems, ribosomes, and chromatin-associated connectivity. By mapping both established and less-characterized interactions, this work advances our understanding of the plant protein interactome and provides a valuable resource for investigating the structural organization of the plant proteome.

molecular biology↗

bioRxiv2025

Next-Generation Mapping of the ACINUS-Mediated Alternative Splicing Machinery and Its Regulation by O-glycosylation in Arabidopsis

Alternative splicing (AS) is a key mechanism of gene regulation, but the full repertoire of proteins involved and the regulatory mechanisms governing this process remain poorly understood. Using TurboID-based proximity labeling coupled with mass spectrometry (PL-MS), we comprehensively mapped the Arabidopsis AS machinery, focusing on the evolutionarily conserved splicing factor ACINUS, its paralog PININ, and the stable interactor SR45. We identified 298 high-confidence components, including both established and novel interactors, providing strong evidence that alternative splicing is coupled to transcription and that multiple RNA processing steps occur simultaneously in plants. Bioinformatic analysis reveals high redundancy, conserved mechanisms, and unique plant-specific features. Selected known and novel interactors were validated by AS readouts and phenotypic analysis, which also revealed a coordinated influence on splicing. Furthermore, a systematic evaluation of O-glycosylation double mutants revealed that SECRET AGENT (O-GlcNAc transferase) and SPINDLY (O-fucose transferase) modulate AS through both ACINUS-dependent and -independent pathways. Our results reveal the conserved as well as plant-specific AS regulatory network and highlight the global role of sugar modification in RNA processing.

plant biology↗

bioRxiv2024

Biomolecular condensation of ERC1 recruits ATG8 and NBR1 to drive autophagosome formation for plant heat tolerance

Macroautophagy (hereafter autophagy) is essential for cells to respond to nutrient stress by delivering cytosolic contents to vacuoles for degradation via the formation of a multi-layer vesicle named autophagosome. A set of autophagy-related (ATG) regulators are recruited to the phagophore assembly site for the initiation of phagophore, as well as its expansion and closure and subsequent delivery into the vacuole. However, it remains elusive that how the phagophore assembly is regulated under different stress conditions. Here, we described an unknown Arabidopsis (Arabidopsis thaliana) cytosolic ATG8-interaction protein family (ERC1/2), that binds ATG8 and NBR1 to promote autophagy. ERC1 proteins translocate to the phagophore membrane and develop into classical ring-like autophagosomes upon autophagic induction. However, ERC1 proteins form large droplets together with ATG8e proteins when in the absence of ATG8 lipidation activity. We described the property of these structures as phase-separated membraneless condensates by solving the in vivo organization with spatial and temporal resolution. Moreover, ERC1 condensates elicits a strong recruitment of the autophagic receptor NBR1. Loss of ERC1 suppressed NBR1 turnover and attenuated plant tolerance to heat stress condition. This work provides novel insights into the mechanical principle of phagophore initiation via an unreported ERC1-mediated biomolecular condensation for heat tolerance in Arabidopsis.

plant biology↗

bioRxiv2024

Next-generation mapping of the salicylic acid signaling hub and transcriptional cascade

For over 60 years, salicylic acid (SA) has been known as a plant immune signal required for both basal and systemic acquired resistance (SAR). SA activates these immune responses by reprogramming up to 20% of the transcriptome through the function of NPR1. However, components in the NPR1-signaling hub, which appears as nuclear condensates, and the NPR1-signaling cascade remained elusive due to difficulties in studying transcriptional cofactors whose chromatin associations are often indirect and transient. To overcome this challenge, we applied TurboID to divulge the NPR1-proxiome, which detected almost all known NPR1-interactors as well as new components of transcription-related complexes. Testing of new components showed that chromatin remodeling and histone demethylation contribute to SA-induced resistance. Globally, NPR1-proxiome shares a striking similarity to GBPL3-proxiome involved in SA synthesis, except associated transcription factors (TFs), suggesting that common regulatory modules are recruited to reprogram specific transcriptomes by transcriptional cofactors, like NPR1, through binding to unique TFs. Stepwise greenCUT&RUN analyses showed that, upon SA-induction, NPR1 initiates the transcriptional cascade primarily through association with TGA TFs to induce expression of secondary TFs, predominantly WRKYs. WRKY54 and WRKY70 then play a major role in inducing immune-output genes without interacting with NPR1 at the chromatin. Moreover, a loss of NPR1 condensate formation decreases its chromatin-association and transcriptional activity, indicating the importance of condensates in organizing the NPR1-signaling hub and initiating the transcriptional cascade. This study demonstrates how combinatorial applications of TurboID and stepwise greenCUT&RUN transcend traditional genetic methods to globally map signaling hubs and transcriptional cascades.

plant biology↗

bioRxiv2023

Chloroplast Methyltransferase Homolog RMT2 is Involved in Photosystem I Biogenesis

Oxygen (O2), a dominant element in the atmosphere and essential for most life on Earth, is produced by the photosynthetic oxidation of water. However, metabolic activity can cause accumulation of reactive O2 species (ROS) and severe cell damage. To identify and characterize mechanisms enabling cells to cope with ROS, we performed a high-throughput O2 sensitivity screen on a genome-wide insertional mutant library of the unicellular alga Chlamydomonas reinhardtii. This screen led to identification of a gene encoding a protein designated Rubisco methyltransferase 2 (RMT2). Although homologous to methyltransferases, RMT2 has not been experimentally demonstrated to have methyltransferase activity. Furthermore, the rmt2 mutant was not compromised for Rubisco (first enzyme of Calvin-Benson Cycle) levels but did exhibit a marked decrease in accumulation/activity of photosystem I (PSI), which causes light sensitivity, with much less of an impact on other photosynthetic complexes. This mutant also shows increased accumulation of Ycf3 and Ycf4, proteins critical for PSI assembly. Rescue of the mutant phenotype with a wild-type (WT) copy of RMT2 fused to the mNeonGreen fluorophore indicates that the protein localizes to the chloroplast and appears to be enriched in/around the pyrenoid, an intrachloroplast compartment present in many algae that is packed with Rubisco and potentially hypoxic. These results indicate that RMT2 serves an important role in PSI biogenesis which, although still speculative, may be enriched around or within the pyrenoid. Significance StatementA high-throughput genetic screen was used to identify O2 sensitive mutants of Chlamydomonas reinhardtii (Chlamydomonas throughout) that experience elevated oxidative stress in the light relative to WT cells. Identification of genes altered in these mutants offers opportunities to discover activities that a) protect photosynthetic cells from oxidative damage, b) participate in rapid assembly of photosynthetic complexes, which would limit accessibility of intermediates to O2, and/or c) facilitate repair of damaged cellular complexes. A mutant from this screen disrupted for RMT2, originally described as encoding a Rubisco methyltransferase, was defective for PSI biogenesis. Additionally, RMT2 appears to be enriched in/around the pyrenoid, a chloroplast localized compartment harboring much of the Chlamydomonas Rubisco, raising the possibility that this compartment plays a role in PSI biogenesis.

plant biology↗

bioRxiv2023

Spatially resolved proteomics of the stomatal lineage: polarity complexes for cell divisions and stomatal pores

Cell polarity is used to guide asymmetric divisions and create morphologically diverse cells. We find that two oppositely oriented cortical polarity domains present during the asymmetric divisions in the Arabidopsis stomatal lineage are reconfigured into polar domains marking ventral (pore-forming) and outward facing domains of maturing stomatal guard cells. Proteins that define these opposing polarity domains were used as baits in miniTurboID-based proximity labeling. Among differentially enriched proteins we find kinases, putative microtubule-interacting proteins, polar SOSEKIs with their effector ANGUSTIFOLIA, and using AI-facilitated protein structure prediction models, we identify their potential interaction interfaces. Functional and localization analysis of polarity protein OPL2 and its newly discovered partners suggest a positive interaction with mitotic microtubules and a potential role in cytokinesis. This combination of cutting-edge proteomics and structural modeling with live cell imaging provides insights into how polarity is rewired in different cell types and cell cycle stages.

developmental biology↗

bioRxiv2023

Nuclear Pyruvate Dehydrogenase Complex Regulates Histone Acetylation and Transcriptional Regulation in the Ethylene Response

Ethylene plays its essential roles in plant development, growth, and defense responses by controlling the transcriptional reprograming, in which EIN2-C-directed regulation of histone acetylation is the first key-step for chromatin to perceive ethylene signaling. But how the nuclear acetyl coenzyme A (acetyl CoA) is produced to ensure the ethylene-mediated histone acetylation is unknown. Here we report that ethylene triggers the accumulation of the pyruvate dehydrogenase complex (PDC) in the nucleus to synthesize nuclear acetyl CoA to regulate ethylene response. PDC is identified as an EIN2-C nuclear partner, and ethylene triggers its nuclear accumulation. Mutations in PDC lead to an ethylene-hyposensitivity that results from the reduction of histone acetylation and transcription activation. Enzymatically active nuclear PDC synthesize nuclear acetyl CoA for EIN2-C-directed histone acetylation and transcription regulation. These findings uncover a mechanism by which PDC-EIN2 converges the mitochondrial enzyme mediated nuclear acetyl CoA synthesis with epigenetic and transcriptional regulation for plant hormone response.

plant biology↗