Biology subjects

Liu, Q.

Publications and source records attributed to Liu, Q..

At least 379 records · Page 21Linked to original sources

bioRxiv2023

Selective S1PR1 activation improves brain infarction, neurological outcome, and cerebrovascular endothelial health following experimental ischemic injury

Sphingosine-1-phosphate receptor 1 (S1PR1) is highly expressed in endothelial cells and receptor activation plays an important role in mediating endothelial function and health, thus showing promise as a pharmacologic target for acute ischemic stroke (AIS) treatment. Here, we examined the effect of a selective S1PR1 ligand, RP101075, on infarct volume and neurological outcome in adult male mice subjected to transient middle cerebral artery occlusion (tMCAO). Concomitantly, we examined S1PR1 expression profile in the ischemic mouse brain, as well as S1PR1 expression and impact of receptor activation on human brain microvascular endothelial cell (HBMEC) proliferation and survival following hypoxia plus glucose deprivation (HGD). We observed that RP101075 administration at onset of reperfusion reduced infarct volume and lessened neurological deficits in tMCAO mice and these responses were S1PR1 dependent. Additionally, we observed that tMCAO increased brain S1PR1 protein levels and flow cytometry revealed increases in S1PR1 levels are greatest in brain endothelial cells compared to other brain cell types (astrocyte, neuron, microglia). In cultured HBMECs, RP101075 increased cell proliferation and ozanimod, parent compound of RP1010175, increased live cell count during HGD; this response was S1PR1 dependent. In conclusion, S1PR1 activation improves neuroprotection/outcome post-stroke and preserves brain endothelial cell survival following ischemia-like injury.

neuroscience↗

bioRxiv2023

Accurate prediction of transcriptional activity of single missense variants in HIV Tat with deep learning

Tat is an essential gene for increasing the transcription of all HIV genes, and it affects HIV replication, HIV exit from latency, and AIDS progression. The Tat gene frequently mutates in vivo producing variants with diverse activities, contributing to HIV viral heterogeneity, as well as drug-resistant clones. Thus, identifying the transcriptional activities of Tat variants will help to better understand AIDS pathology and treatment. We recently reported the missense mutation landscape of all single amino acid Tat variants. In these experiments, a fraction of double missense alleles exhibited intragenic epistasis. It is too time-consuming and costly to determine a variants effect for all double mutant alleles with experiments. Therefore, we propose a combined GigaAssay/Deep learning approach. As a first step for determining activity landscapes for complex variants, we evaluated a deep learning framework using previously reported GigaAssay experiments to predict how transcription activity is affected by Tat variants with single missense substitutions. Our approach achieves a 0.94 Pearson correlation coefficient when comparing experimental to predicted activities. This hybrid approach should be extensible to more complex Tat alleles for better understanding the genetic control of HIV genome transcription.

bioinformatics↗

bioRxiv2023

Asynchronous phylogeographic and demographic dynamics of rodent community in the low latitude Asia

It is increasing evident that demographic history and phylogeographic consequences of past climate changes were unfolded locally and varied from region to region. Despite the high Murinae rodent species richness and endemism in the low latitude Asia, how the past climatic fluctuations shaped the phylogeographic and demographic history in this area remains unknown. Here we trapped 253 field Murine individuals and successfully amplified COI gene sequence for DNA barcoding. The phylogenetic tree showed the Murinae diversification included ten species belong to Rattini and Murini tribes. The divergence dating suggested that the most common ancestor (TMRCA) of each rodent species was estimated in Early or Middle Pleistocene. Bayesian skyline plot (BSP) exhibited the onset of population growth of seven Murinae rodents occurred at penultimate or last glaciation, and while R. losea and R. norvegicus keep effective population size constant through their elapsed time. Additionally, the six rodent species range of refugia area in the LGM projected by ecological niche models (ENMs) exhibited expander than the suitable area on present, meanwhile the remaining four rodent species showed contracted refugia regions. Hence, our results suggested that the rodent community displayed the asynchronous demographic and phylogeographic dynamics in the low latitude Asia.

molecular biology↗

bioRxiv2023

Molecular cartography uncovers evolutionary and microenvironmental dynamics in sporadic colorectal tumors

Colorectal cancer exhibits dynamic cellular and genetic heterogeneity during progression from precursor lesions toward malignancy. Leveraging spatial molecular information to construct a phylogeographic map of tumor evolution can reveal individualized growth trajectories with diagnostic and therapeutic potential. Integrative analysis of spatial multi-omic data from 31 colorectal specimens revealed simultaneous microenvironmental and clonal alterations as a function of progression. Copy number variation served to re-stratify microsatellite stable and unstable tumors into chromosomally unstable (CIN+) and hypermutated (HM) classes. Phylogeographical maps classified tumors by their evolutionary dynamics, and clonal regions were placed along a global pseudotemporal progression trajectory. Cell-state discovery from a single-cell cohort revealed recurring epithelial gene signatures and infiltrating immune states in spatial transcriptomics. Charting these states along progression pseudotime, we observed a transition to immune exclusion in CIN+ tumors as characterized by a novel gene expression signature comprised of DDR1, TGFBI, PAK4, and DPEP1. We demonstrated how these genes and their protein products are key regulators of extracellular matrix components, are associated with lower cytotoxic immune infiltration, and show prognostic value in external cohorts. Through high-dimensional data integration, this atlas provides insights into co-evolution of tumors and their microenvironments, serving as a resource for stratification and targeted treatment of CRC.

systems biology↗

bioRxiv2023

Viruses in deep-sea cold seep sediments harbor diverse survival mechanisms and remain genetically conserved within species

Deep sea cold seep sediments have been discovered to harbor novel, abundant, and diverse bacterial and archaeal viruses. However, little is known about viral genetic features and evolutionary patterns in these environments. Here, we examined the evolutionary ecology of viruses across active and extinct seep stages in the area of Haima cold seeps in the South China Sea. Diverse antiviral defense systems in 487 microbial genomes spanning 43 families inform the dynamics of host-virus interactions. Accordingly, a total of 338 viral operational taxonomic units are identified and linked to 36 bacterial and archaeal phyla. Cold seep viruses are predicted to harbor diverse adaptive strategies to persist in this environment, including counter-defense systems, reverse transcriptases, auxiliary metabolic genes, and alternative genetic code assignments. Extremely low nucleotide diversity is observed in cold seep viral populations, being influenced by factors including microbial host, sediment depth and cold seep stage. Most cold seep viral genes are under strong purifying selection with trajectories that differ depending on whether cold seeps are active or extinct. This work sheds light on the understanding of environmental adaptation mechanisms and evolutionary patterns of viruses in the sub-seafloor biosphere.

microbiology↗

bioRxiv2023

BRD9-SMAD2/3 orchestrates stemness and tumorigenesis in pancreatic ductal adenocarcinoma

The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodelling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGF{beta}/Activin-SMAD2/3 signalling pathway. Inhibition and genetic ablation of BDR9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumours from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs. Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

cancer biology↗

bioRxiv2023

Retrieved Sequence Augmentation for Protein Representation Learning

The advancement of protein representation learning has been significantly influenced by the remarkable progress in language models. Accordingly, protein language models perform inference from individual sequences, thereby limiting their capacity to incorporate evolutionary knowledge present in sequence variations. Existing solutions, which rely on Multiple Sequence Alignments (MSA), suffer from substantial computational overhead and suboptimal generalization performance for de novo proteins. In light of these problems, we introduce a novel paradigm called Retrieved Sequence Augmentation (RSA) that enhances protein representation learning without necessitating additional alignment or preprocessing. RSA associates query protein sequences with a collection of structurally or functionally similar sequences in the database and integrates them for subsequent predictions. We demonstrate that protein language models benefit from retrieval enhancement in both structural and property prediction tasks, achieving a 5% improvement over MSA Transformer on average while being 373 times faster. Furthermore, our model exhibits superior transferability to new protein domains and outperforms MSA Transformer in de novo protein prediction. This study fills a much-encountered gap in protein prediction and brings us a step closer to demystifying the domain knowledge needed to understand protein sequences. Code is available at https://github.com/HKUNLP/RSA.

bioinformatics↗

bioRxiv2023

CXCR2 expression during melanoma tumorigenesis controls transcriptional programs that facilitate tumor growth

BackgroundThough the CXCR2 chemokine receptor is known to play a key role in cancer growth and response to therapy, a direct link between expression of CXCR2 in tumor progenitor cells during induction of tumorigenesis has not been established. MethodsTo characterize the role of CXCR2 during melanoma tumorigenesis, we generated tamoxifen-inducible tyrosinase-promoter driven BrafV600E/Pten-/-/Cxcr2-/- and NRasQ61R/INK4a-/-/Cxcr2-/- melanoma models. In addition, the effects of a CXCR1/CXCR2 antagonist, SX-682, on melanoma tumorigenesis were evaluated in BrafV600E/Pten-/- and NRasQ61R/INK4a-/- mice and in melanoma cell lines. Potential mechanisms by which Cxcr2 affects melanoma tumorigenesis in these murine models were explored using RNAseq, mMCP-counter, ChIPseq, and qRT-PCR; flow cytometry, and reverse phosphoprotein analysis (RPPA). ResultsGenetic loss of Cxcr2 or pharmacological inhibition of CXCR1/CXCR2 during melanoma tumor induction resulted in key changes in gene expression that reduced tumor incidence/growth and increased anti-tumor immunity. Interestingly, after Cxcr2 ablation, Tfcp2l1, a key tumor suppressive transcription factor, was the only gene significantly induced with a log2 fold-change greater than 2 in these three different melanoma models. ConclusionsHere, we provide novel mechanistic insight revealing how loss of Cxcr2 expression/activity in melanoma tumor progenitor cells results in reduced tumor burden and creation of an anti-tumor immune microenvironment. This mechanism entails an increase in expression of the tumor suppressive transcription factor, Tfcp2l1, along with alteration in the expression of genes involved in growth regulation, tumor suppression, stemness, differentiation, and immune modulation. These gene expression changes are coincident with reduction in the activation of key growth regulatory pathways, including AKT and mTOR.

cancer biology↗

bioRxiv2023

RNPS1 stabilizes NAT10 protein to facilitate translation in cancer via tRNA ac4C modification

NAT10 is dysregulated and plays an essential role in various types of cancers. However, the exact machenism of how NAT10 regulates cancer progression remains debatable. In this report, we show that NAT10 affects tumorigeneis mainly based on its acetylation function on tRNA. In addition, we found NAT10 regulate the ac4C of tRNA in cancer via interaction with RNPS1, which in turn protect NAT10 from degradation by E3 ubiquitin ligase ZSWIM6. We developed TRMC-seq method to compreshensively profile tRNA ac4C sites and uncovered the presence of ac4C in a broader range of tRNA isoacceptors than previous studies. Multi-omics analysis identified AP-1 signaling pathway as a major downstream mediator of NAT10. Mechanistically, we found NAT10 is responsible for the translation efficiency genes which contain higher ac4C-tRNA codon. Importantly, our genetic mouse model validated our in vitro findings of NAT10 in cancer. Our study highlights a role of NAT10 in mediating tRNA ac4C to regulate the translation and tumorigenesis of cancer.

molecular biology↗

bioRxiv2023

Integrating AlphaFold and deep learning for atomistic interpretation of cryo-EM maps

Interpretation of cryo-electron microscopy (cryo-EM) maps requires building and fitting 3-D atomic models of biological molecules. AlphaFold-predicted models generate initial 3-D coordinates; however, model inaccuracy and conformational heterogeneity often necessitate labor-intensive manual model building and fitting into cryo-EM maps. In this work, we designed a protein modelbuilding workflow, which combines a deep-learning cryo-EM map feature enhancement tool, CryoFEM (Cryo-EM Feature Enhancement Model) and AlphaFold. A benchmark test using 36 cryo-EM maps shows that CryoFEM achieves state-of-the-art performance in optimizing the Fourier Shell Correlations between the maps and the ground truth models. Furthermore, in a subset of 17 datasets where the initial AlphaFold predictions are less accurate, the workflow significantly improves their model accuracy. Our work demonstrates that the integration of modern deep learning image enhancement and AlphaFold may lead to automated model building and fitting for the atomistic interpretation of cryo-EM maps.

bioinformatics↗

bioRxiv2023

Single-cell transcriptomic landscape deciphers novel olfactory neuroblastoma subtypes and intratumoral heterogeneity

Olfactory neuroblastoma (ONB) is an uncommon malignant tumor known to originate from the olfactory epithelial. The complex tumor ecosystem of this pathology remained unclear. Here, we explored the cellular components with ONB tumors based on scRNA profiles of 96,325 single-cells derived from 10 tumors and 1 olfactory mucosa sample. We discovered 11 major cell types, including 6 immune cell, 3 stromal cell subtypes and epithelial cluster in the tumor microenvironment (TME), and identified 5 common expression programs from malignant epithelial cells. We analyzed subclusters of TME and the interactions among different cell types in the TME. An innovative three-classification of ONB was established via scRNA analysis. Markers for categorizing tumor samples into new subtypes were elucidated. Different responses towards certain chemotherapy regimens could be inferred according to the molecular features of three tumor types. Relative abundance of immunosuppressive TAMs indicated the benefits of immunotherapies targeting myeloid cells.

cancer biology↗

bioRxiv2023

Dasatinib Resensitizes MAPK Inhibitor Efficacy in Standard-of-Care Relapsed Melanomas

Resistance to combination BRAF/MEK inhibitor (BRAFi/MEKi) therapy arises in nearly every patient with BRAFV600E/K melanoma, despite promising initial responses. Achieving cures in this expanding BRAFi/MEKi-resistant cohort represents one of the greatest challenges to the field; few experience additional durable benefit from immunotherapy and no alternative therapies exist. To better personalize therapy in cancer patients to address therapy relapse, umbrella trials have been initiated whereby genomic sequencing of a panel of potentially actionable targets guide therapy selection for patients; however, the superior efficacy of such approaches remains to be seen. We here test the robustness of the umbrella trial rationale by analyzing relationships between genomic status of a gene and the downstream consequences at the protein level of related pathway, which find poor relationships between mutations, copy number amplification, and protein level. To profile candidate therapeutic strategies that may offer clinical benefit in the context of acquired BRAFi/MEKi resistance, we established a repository of patient-derived xenograft models from heavily pretreated patients with resistance to BRAFi/MEKi and/or immunotherapy (R-PDX). With these R-PDXs, we executed in vivo compound repurposing screens using 11 FDA-approved agents from an NCI-portfolio with pan-RTK, non-RTK and/or PI3K-mTOR specificity. We identify dasatinib as capable of restoring BRAFi/MEKi antitumor efficacy in [~]70% of R-PDX tested. A systems-biology analysis indicates elevated baseline protein expression of canonical drivers of therapy resistance (e.g., AXL, YAP, HSP70, phospho-AKT) as predictive of MAPKi/dasatinib sensitivity. We therefore propose that dasatinib-based MAPKi therapy may restore antitumor efficacy in patients that have relapsed to standard-of-care therapy by broadly targeting proteins critical in melanoma therapy escape. Further, we submit that this experimental PDX paradigm could potentially improve preclinical evaluation of therapeutic modalities and augment our ability to identify biomarker-defined patient subsets that may respond to a given clinical trial. SINGLE SENTENCE SUMMARYBroad target inhibition effective as a salvage strategy in BRAF/MEK inhibitor-acquired resistance PDX

cancer biology↗

bioRxiv2023

Identification and Characterization of a Novel Major Facilitator Superfamily (MFS) Efflux Pump SA09310 Mediating Tetracycline Resistance in Staphylococcus aureus

Drug efflux systems have recently been recognized as an important mechanism of multidrug resistance in bacteria. Here, we described the identification and characterization of a novel chromosomally encoded multidrug efflux pump (SA09310) in Staphylococcus aureus. SA09310 is a 43-kDa protein with 12 transmembrane helices. The conserved amino acid sequence motifs of the major facilitator superfamily (MFS) were identified in the protein SA09310, which indicated SA09310 belonged to MFS transporters. Expression of the sa09310 gene was induced by different types of antibiotics, including aminoglycoside, tetracycline, macrolides, and chloramphenicol. The sa09310 gene knockout mutant ({Delta}sa09310) was constructed, and its susceptibility to 30 different antibiotics was evaluated. Mutant{bigtriangleup} sa09310 exhibited increased sensitivity to tetracycline and doxycycline, with 64-fold and 8-fold decreased MICs, respectively. The mechanism of SA09310 mediating tetracycline resistance was demonstrated by its ability to extrude intracellular tetracycline from within the cells into the environment. The efflux activity of SA09310 was further confirmed by EtBr accumulation and efflux assays. In addition, the efflux activity of SA09310 was observed to be blocked by the known efflux pump inhibitor carbonyl cyanide-chlorophenylhydrazone (CCCP), which provided direct evidence that suggested the H+-dependent activity of SA09310 efflux pump. The conservation of SA09310 homologs in Staphylococcus indicated the universal function of these SA09310-like protein clusters. In conclusion, the function-unknown protein SA09310 has been identified and characterized as a tetracycline efflux pump, thereby mediating tetracycline resistance in S. aureus.

microbiology↗

bioRxiv2023

CircPLXNA2 affects the proliferation and apoptosis of myoblast through circPLXNA2/gga-miR-12207-5P/MDM4 axis

BackgroundcircRNAs are new-identified special endogenous RNA molecules that covalently close a loop by backsplicing with pre-mRNA. In the cytoplasm, circRNAs would act as molecular sponges to bind with specific miRNA to promote the expression of target genes. However, there is still in its fancy of knowing circRNA functional alternation in skeletal myogenesis. In this study, we favor a model to identify the circRNA-miRNA-mRNA interaction network in which the axis may be implicated in the progression of chicken primary myoblasts (CPMs) myogenesis by a combination of multi-omics (i.e., circRNA-seq and ribo-seq). ResultsIn total, 314 circRNA-miRNA-mRNA regulatory axis containing 66 circRNAs, 70 miRNAs, and 24 mRNAs that may be relevant to myogenesis were collected. With these, the circPLXNA2-gga-miR-12207-5P-MDM4 axis aroused our research interest. The circPLXNA2 is highly differentially expressed during differentiation versus proliferation. It was demonstrated that circPLXNA2 inhibited the process of apoptosis while at the same time stimulating cell proliferation. Furthermore, we demonstrated that circPLXNA2 could inhibit the repression of gga-miR-12207-5p to MDM4 by directing binding to gga-miR-12207-5p, thereby restoring MDM4 expression. ConclusionsCircPLXNA2 could function as a competing endogenous RNA (ceRNA) to inhibit the repression of gga-miR-12207-5p to MDM4 by directing binding to gga-miR-12207-5p, thereby recovering the expression of MDM4.

molecular biology↗

bioRxiv2022

Haploid-resolved and chromosome-scale genome assembly in hexa-autoploid sweetpotato (Ipomoea batatas (L.) Lam)

Sweetpotato (Ipomoea batatas (L.) Lam) is the worlds seventh most important food crop by production quantity. Cultivated sweetpotato is a hexaploid (2n = 6x = 90), and its genome (B1B1B2B2B2B2) is quite complex due to polyploidy, self-incompatibility, and high heterozygosity. Here we established a haploid-resolved and chromosome-scale de novo assembly of autohexaploid sweetpotato genome sequences. Before constructing the genome, we created chromosome-scale genome sequences in I. trifida using a highly homozygous accession, Mx23Hm, with PacBio RSII and Hi-C reads. Haploid-resolved genome assembly was performed for a sweetpotato cultivar, Xushu18 by hybrid assembly with Illumina paired-end (PE) and mate-pair (MP) reads, 10X genomics reads, and PacBio RSII reads. Then, 90 chromosome-scale pseudomolecules were generated by aligning the scaffolds onto a sweetpotato linkage map. De novo assemblies were also performed for chloroplast and mitochondrial genomes in I. trifida and sweetpotato. In total, 34,386 and 175,633 genes were identified on the assembled nucleic genomes of I. trifida and sweetpotato, respectively. Functional gene annotation and RNA-Seq analysis revealed locations of starch, anthocyanin, and carotenoid pathway genes on the sweetpotato genome. This is the first report of chromosome-scale de novo assembly of the sweetpotato genome. The results are expected to contribute to genomic and genetic analyses of sweetpotato.

genomics↗

bioRxiv2022

Inverse Agonist Activity of Angiotensin II Receptor Blocker Is Crucial for Prevention of Aortic Aneurysm Formation in Marfan Syndrome

BackgroundMarfan syndrome (MFS), an inherited disorder caused by FBN1 gene mutations, causes fatal aortic aneurysm. Selective angiotensin II (Ang II) type 1 (AT1) receptor blockade is a preventive option for patients with MFS aortopathy, and recent clinical studies demonstrated that the inhibitory effect of an AT1 receptor blocker (ARB) losartan on aortic aneurysm growth is equivalent to that of {beta}-blockers. At present, several ARBs are clinically available, and they have drug-specific differences in pharmacological properties. Especially, inverse agonism of ARBs has potential benefits for cardiovascular protection, but its impact on MFS aortopathy remains poorly understood. MethodsCandesartan-7H is a candesartan derivative which lacks the carboxyl group critical for inverse agonist activity and works as a neutral antagonist for AT1 receptor. Candesartan cilexetil (1 mg/kg/day), candesartan-7H (1 mg/kg/day or 20 mg/kg/day), or vehicle was administered to Fbn1C1041G/+ mice, and aortic aneurysm formation was analyzed using echocardiography, histological staining, and in situ MMP assay. Activation of TGF-{beta} signaling and mechanosensitive signaling was studied using western blot and immunohistochemical analysis. ResultsCandesartan cilexetil (1 mg/kg/day) and candesartan-7H (20 mg/kg/day) lowered blood pressures equally in Fbn1C1041G/+ mice, but that candesartan-7H (1 mg/kg/day) did not. Aortic aneurysmal progression in association with aortic wall thickening, degeneration of elastic fibers, deposition of collagen, MMP activation, and TGF-{beta} signaling activation in Fbn1C1041G/+ mice was significantly suppressed by treatment with candesartan cilexetil (1 mg/kg/day), but not by candesartan-7H even at 20 mg/kg/day. In addition, candesartan cilexetil, but not candesartan-7H, inhibited up-regulation of mechanical stress-responsive transcriptional factor Egr-1 in ascending aorta of Fbn1C1041G/+ mice. ConclusionsOur findings support a crucial role of inverse agonist activity of ARB for prevention of mechanical stress-induced AT1 receptor activation and aortic aneurysm formation in MFS mice.

pharmacology and toxicology↗

bioRxiv2022

PXN/Paxillin Phase Separation Promotes Focal Adhesion Assembly and Integrin Signaling

Focal adhesions (FAs) are transmembrane protein assemblies mediating cell-matrix connection. Tools to manipulate the compositionally intricate and dynamic FAs are currently limited, rendering many fundamental hypotheses untestable. Although protein liquid-liquid phase separation (LLPS) has been tied to the organization and dynamics of FAs, the underlying mechanisms remain unclear. Here, we experimentally tune the LLPS of PXN/Paxillin, an essential scaffold protein of FAs, by utilizing light-inducible Cry2 system. In addition to nucleating FA components, light-triggered PXN LLPS potently activates integrin signaling and subsequently accelerates cell spreading. PXN favors homotypic interaction-driven LLPS in vitro. In cells, PXN condensates are associated with plasma membrane, and modulated by actomyosin contraction and client proteins of FAs. Interestingly, non-specific weak inter-molecular interactions, together with specific molecular interactions, underlie the multicomponent condensation of PXN, and are efficient to promote FA assembly and integrin signaling. Thus, our data establish an active role of PXN phase transition into a condensed membrane-associated compartment in promoting assembly/maturation of FAs.

cell biology↗

bioRxiv2022

Large-scale analysis of the N-terminal regulatory elements of the kinase domain in plant receptor-like kinase family

The N-terminal regulatory element of the kinase domain (NRE), which includes juxtamembrane segment (JM) of Receptor-like kinases (RLKs) and the N-terminal extension segment of the kinase domain in RLCKs, is the key component that regulates the activities of RLKs and RLCKs. However, their feature and functions remain largely unexplored. Herein, we perform a systematic analysis of 510,233 NRE sequences in RLKs and RLCKs from 528 plants by integrating information theory and genome-wide analysis to unravel their common characteristics and diversity. Recombinant RLKs are used to explore the structural-functional relationship of the newly-discovered motifs in vitro. Most NRE segments are around 40-80 amino acids, featuring a serine-rich region and a 14-amino-acid motif FSYEELEKATBNFS which harbors a characteristic -helix connecting to the core kinase domain. This -helix suppresses FERONIAs kinase activity. Motif discovery algorithm has identified 29 motifs with known phosphorylation sites highly conserved in RLK and RLCK classes, especially the motif VGPWKpTGLpSGQLQKAFVTGVP in LRR-VI-2 class. The NRE phosphorylation of an LRR-VI-2 member MDIS1 modulates the auto-phosphorylation of its co-receptor MIK1, indicating NREs potential role as a "kinase switch" in RLK activation. Consequently, the characterization of phosphorylatable NRE motifs improves the accuracy in predicting phosphorylatable serines. Altogether, our study provides an enriched and comprehensive dataset to investigate NRE segments from individual RLKs and helps understand the underlying mechanism of action of the RLK signal transduction and kinase activation processes in plant adaptation.

plant biology↗