Phosphatases: Decoding the Role of Mycorrhizal Fungi in Plant Disease Resistance.

Mycorrhizal fungi, a category of fungi that form symbiotic relationships with plant roots, can participate in the induction of plant disease resistance by secreting phosphatase enzymes. While extensive research exists on the mechanisms by which mycorrhizal fungi induce resistance, the specific contributions of phosphatases to these processes require further elucidation. This article reviews the spectrum of mycorrhizal fungi-induced resistance mechanisms and synthesizes a current understanding of how phosphatases mediate these effects, such as the induction of defense structures in plants, the negative regulation of plant immune responses, and the limitation of pathogen invasion and spread. It explores the role of phosphatases in the resistance induced by mycorrhizal fungi and provides prospective future research directions in this field.

Single-Atom Ce-Doped Metal Hydrides with High Phosphatase-like Activity Amplify Oxidative Stress-Induced Tumor Apoptosis.

Phosphates within tumors function as key biomolecules, playing a significant role in sustaining the viability of tumors. To disturb the homeostasis of cancer cells, regulating phosphate within the organism proves to be an effective strategy. Herein, we report single-atom Ce-doped Pt hydrides (Ce/Pt-H) with high phosphatase-like activity for phosphate hydrolysis. The resultant Ce/Pt-H exhibits a 26.90- and 6.25-fold increase in phosphatase-like activity in comparison to Ce/Pt and Pt-H, respectively. Mechanism investigations elucidate that the Ce Lewis acid site facilitates the coordination with phosphate groups, while the surface hydrides enhance the electron density of Pt for promoting catalytic ability in H2O cleavage and subsequent nucleophilic attack of hydroxyl groups. Finally, by leveraging its phosphatase-like activity, Ce/Pt-H can effectively regulate intracellular phosphates to disrupt redox homeostasis and amplify oxidative stress within cancer cells, ultimately leading to tumor apoptosis. This work provides fresh insights into noble-metal-based phosphatase mimics for inducing tumor apoptosis.

INPP4B promotes PDAC aggressiveness via PIKfyve and TRPML-1-mediated lysosomal exocytosis.

Aggressive solid malignancies, including pancreatic ductal adenocarcinoma (PDAC), can exploit lysosomal exocytosis to modify the tumor microenvironment, enhance motility, and promote invasiveness. However, the molecular pathways through which lysosomal functions are co-opted in malignant cells remain poorly understood. In this study, we demonstrate that inositol polyphosphate 4-phosphatase, Type II (INPP4B) overexpression in PDAC is associated with PDAC progression. We show that INPP4B overexpression promotes peripheral dispersion and exocytosis of lysosomes resulting in increased migratory and invasive potential of PDAC cells. Mechanistically, INPP4B overexpression drives the generation of PtdIns(3,5)P2 on lysosomes in a PIKfyve-dependent manner, which directs TRPML-1 to trigger the release of calcium ions (Ca2+). Our findings offer a molecular understanding of the prognostic significance of INPP4B overexpression in PDAC through the discovery of a novel oncogenic signaling axis that orchestrates migratory and invasive properties of PDAC via the regulation of lysosomal phosphoinositide homeostasis.

The AtMINPP Gene, Encoding a Multiple Inositol Polyphosphate Phosphatase, Coordinates a Novel Crosstalk between Phytic Acid Metabolism and Ethylene Signal Transduction in Leaf Senescence.

Plant senescence is a highly coordinated process that is intricately regulated by numerous endogenous and environmental signals. The involvement of phytic acid in various cell signaling and plant processes has been recognized, but the specific roles of phytic acid metabolism in Arabidopsis leaf senescence remain unclear. Here, we demonstrate that in Arabidopsis thaliana the multiple inositol phosphate phosphatase (AtMINPP) gene, encoding an enzyme with phytase activity, plays a crucial role in regulating leaf senescence by coordinating the ethylene signal transduction pathway. Through overexpressing AtMINPP (AtMINPP-OE), we observed early leaf senescence and reduced chlorophyll contents. Conversely, a loss-of-function heterozygous mutant (atminpp/+) exhibited the opposite phenotype. Correspondingly, the expression of senescence-associated genes (SAGs) was significantly upregulated in AtMINPP-OE but markedly decreased in atminpp/+. Yeast one-hybrid and chromatin immunoprecipitation assays indicated that the EIN3 transcription factor directly binds to the promoter of AtMINPP. Genetic analysis further revealed that AtMINPP-OE could accelerate the senescence of ein3-1eil1-3 mutants. These findings elucidate the mechanism by which AtMINPP regulates ethylene-induced leaf senescence in Arabidopsis, providing insights into the genetic manipulation of leaf senescence and plant growth.

PD-1 signaling limits expression of phospholipid phosphatase 1 and promotes intratumoral CD8+ T cell ferroptosis.

The tumor microenvironment (TME) promotes metabolic reprogramming and dysfunction in immune cells. Here, we examined the impact of the TME on phospholipid metabolism in CD8+ T cells. In lung cancer, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were lower in intratumoral CD8+ T cells than in circulating CD8+ T cells. Intratumoral CD8+ T cells exhibited decreased expression of phospholipid phosphatase 1 (PLPP1), which catalyzes PE and PC synthesis. T cell-specific deletion of Plpp1 impaired antitumor immunity and promoted T cell death by ferroptosis. Unsaturated fatty acids in the TME stimulated ferroptosis of Plpp1-/- CD8+ T cells. Mechanistically, programmed death-1 (PD-1) signaling in CD8+ T cells induced GATA1 binding to the promoter region Plpp1 and thereby suppressed Plpp1 expression. PD-1 blockade increased Plpp1 expression and restored CD8+ T cell antitumor function but did not rescue dysfunction of Plpp1-/- CD8+ T cells. Thus, PD-1 signaling regulates phospholipid metabolism in CD8+ T cells, with therapeutic implications for immunotherapy.

Identification of YigL as a PLP/PNP phosphatase in Escherichia coli.

In various organisms, the coenzyme form of vitamin B6, pyridoxal phosphate (PLP), is synthesized from pyridoxine phosphate (PNP). Control of PNP levels is crucial for metabolic homeostasis because PNP has the potential to inhibit PLP-dependent enzymes and proteins. Although the only known pathway for PNP metabolism in Escherichia coli involves oxidation by PNP oxidase, we detected a strong PNP phosphatase activity in E. coli cell lysate. To identify the unknown PNP phosphatase(s), we performed a multicopy suppressor screening using the E. coli serA pdxH strain, which displays PNP-dependent conditional lethality. The results showed that overexpression of the yigL gene, encoding a putative sugar phosphatase, effectively alleviated the PNP toxicity. Biochemical analysis revealed that YigL has strong phosphatase activity against PNP. A yigL mutant exhibited decreased PNP phosphatase activity, elevated intracellular PNP concentrations, and increased PNP sensitivity, highlighting the important role of YigL in PNP homeostasis. YigL also shows reactivity with PLP. The phosphatase activity of PLP in E. coli cell lysate was significantly reduced by mutation of yigL and nearly abolished by additional mutation of ybhA, which encodes putative PLP phosphatase. These results underscore the important contribution of YigL, in combination with YbhA, as a primary enzyme in the dephosphorylation of both PNP and PLP in E. coli.IMPORTANCEPyridoxine phosphate (PNP) metabolism is critical for both vitamin B6 homeostasis and cellular metabolism. In Escherichia coli, oxidation of PNP was the only known mechanism for controlling PNP levels. This study uncovered a novel phosphatase-mediated mechanism for PNP homeostasis. Multicopy suppressor screening, kinetic analysis of the enzyme, and knockout/overexpression studies identified YigL as a key PNP phosphatase that contributes to PNP homeostasis when facing elevated PNP concentrations in E. coli. This study also revealed a significant contribution of YigL, in combination with YbhA, to PLP metabolism, shedding light on the mechanisms of vitamin B6 regulation in bacteria.

The Phosphatase RosC from Streptomyces davaonensis is Used for Roseoflavin Biosynthesis and has Evolved to Largely Prevent Dephosphorylation of the Important Cofactor Riboflavin-5'-phosphate.

The antibiotic roseoflavin is a riboflavin (vitamin B2) analog. One step of the roseoflavin biosynthetic pathway is catalyzed by the phosphatase RosC, which dephosphorylates 8-demethyl-8-amino-riboflavin-5'-phosphate (AFP) to 8-demethyl-8-amino-riboflavin (AF). RosC also catalyzes the potentially cell-damaging dephosphorylation of the AFP analog riboflavin-5'-phosphate also called "flavin mononucleotide" (FMN), however, with a lower efficiency. We performed X-ray structural analyses and mutagenesis studies on RosC from Streptomyces davaonensis to understand binding of the flavin substrates, the distinction between AFP and FMN and the catalytic mechanism of this enzyme. This work is the first structural analysis of an AFP phosphatase. Each monomer of the RosC dimer consists of an α/ß-fold core, which is extended by three specific elongated strand-to-helix sections and a specific N-terminal helix. Altogether these segments envelope the flavin thereby forming a novel flavin-binding site. We propose that distinction between AFP and FMN is provided by substrate-induced rigidification of the four RosC specific supplementary segments mentioned above and by an interaction between the amino group at C8 of AFP and the ß-carboxylate of D166. This key amino acid is involved in binding the ring system of AFP and positioning its ribitol phosphate part. Accordingly, site-specific exchanges at D166 disturbed the active site geometry of the enzyme and drastically reduced the catalytic activity. Based on the structure of the catalytic core we constructed a whole series of RosC variants but a disturbing, FMN dephosphorylating "killer enzyme", was not generated.

Potentially functional variants of INPP5D and EXOSC3 in immunity B cell-related genes are associated with non-small cell lung cancer survival.

B cells are adaptive immune cells in the tumor microenvironment and play an important role in tumor development and metastasis. However, the roles of genetic variants of the immunity B cell-related genes in the survival of patients with non-small cell lung cancer (NSCLC) remain unknown. In the present study, we first evaluated associations between 10,776 single nucleotide polymorphisms (SNPs) in 220 immunity B cell-related genes and survival of NSCLC in a discovery dataset of 1,185 patients from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. We found that 369 SNPs were significantly associated with overall survival (OS) of NSCLC in multivariable Cox proportional hazards regression analysis (P ≤ 0.05, Bayesian false discovery probability ≤ 0.80), of which 18 SNPs were validated in another independent genotyping dataset of 984 patients from the Harvard Lung Cancer Susceptibility (HLCS) Study. We then performed linkage disequilibrium (LD) analysis, followed by stepwise analysis with a multivariable Cox regression model. Finally, two independent SNPs, inositol polyphosphate-5-phosphatase D (INPP5D) rs13385922 C>T and exosome component 3 (EXOSC3) rs3208406 A>G, remained significantly associated withNSCLC OS with a combined hazards ratio (HR) of 1.14 (95% confidence interval = 1.06-1.23, P = 2.41×10-4) and 1.20 (95% confidence interval = 1.14-1.28, P = 3.41×10-9), respectively. Furthermore, NSCLC patients with the combination of unfavorable genotypes for these two SNPs were associated with a poor OS (P trend = 0.0002) and disease-specific survival (DSS, P trend < 0.0001) in the PLCO dataset. Expression quantitative trait loci (eQTL) analysis suggested that the INPP5D rs6782875 T allele was significantly correlated with elevated INPP5D mRNA expression levels in normal lung tissues and whole blood samples, while the EXOSC3 rs3208406 G allele was significantly correlated with increased EXOSC3 mRNA expression levels in normal lung tissues. Our data indicated that genetic variants in these immunity B cell-related genes may predict NSCLC survival possibly by influencing the gene expression.

Clinical Characteristics of Charcot-Marie-Tooth Disease Type 4J.

BACKGROUND AND OBJECTIVES: Charcot-Marie-Tooth disease type 4J (CMT4J) is caused by autosomal recessive variants in the Factor-Induced Gene 4 (FIG4) gene. Recent preclinical work has demonstrated the feasibility of adeno-associated virus serotype 9-FIG4 gene therapy. This study aimed to further characterize the CMT4J phenotype and evaluate feasibility of validated CMT-related outcome measures for future clinical trials. METHODS: This cross-sectional study enrolled children and adults with genetically confirmed CMT4J, with 2 documented disease-causing variants in the FIG4 gene. Patients were recruited through the Inherited Neuropathy Consortium network. Disease severity was assessed using standardized CMT-specific outcome measures and exploratory biomarkers including muscle MRI fat fraction, electrophysiology, and neurofilament light chain levels. Descriptive statistics and correlation analyses were conducted to explore relationships between variables. RESULTS: We recruited a total of 19 patients, including 14 pediatric patients (mean age 10.9 ± 3.9 years) and 5 adults (mean age 40.0 ± 13.9 years). The most frequent symptoms were gross motor delay and distal more than proximal muscle weakness, which were observed in 14 of 19 patients. The most common non-neuromuscular symptoms were cognitive and respiratory deficits, each seen in 8 of 19 patients. We denoted asymmetric weakness in 2 patients and nonuniform slowing of conduction velocities in 6 patients. Charcot-Marie-Tooth Disease Pediatric Scale (CMTPedS), Pediatric Quality of Life Inventory, and Vineland Adaptive Behavior Scale scores were affected in most patients. We observed a significant positive correlation between neurofilament light chain levels and CMTPedS, but the study was underpowered to observe a correlation between CMTPedS and MRI fat fraction. DISCUSSION: We obtained baseline clinical and biomarker data in a broad cohort with CMT4J in pediatric and adult patients. Motor delay, muscle weakness, and respiratory and cognitive difficulties were the most common clinical manifestations of CMT4J. Many patients had nerve conduction studies with nonuniform slowing, and 2 had an asymmetric pattern of muscle weakness. We observed that the neurofilament light chain levels correlated with the CMTPedS in the pediatric population. This study showed feasibility of clinical outcomes including CMTPedS in assessment of disease severity in the pediatric patient population and provided baseline characteristics of exploratory biomarkers, neurofilament light chain levels, and muscle MRI fat fraction. The coronavirus disease 2019 pandemic affected some of the visits, resulting in a reduced number of some of the assessments.

Inositol Pyrophosphates as Versatile Metabolic Messengers.

Discovered in 1993, inositol pyrophosphates are evolutionarily conserved signaling metabolites whose versatile modes of action are being increasingly appreciated. These include their emerging roles as energy regulators, phosphodonors, steric/allosteric regulators, and G protein-coupled receptor messengers. Through studying enzymes that metabolize inositol pyrophosphates, progress has also been made in elucidating the various cellular and physiological functions of these pyrophosphate-containing, energetic molecules. The two main forms of inositol pyrophosphates, 5-IP7 and IP8, synthesized respectively by inositol-hexakisphosphate kinases (IP6Ks) and diphosphoinositol pentakisphosphate kinases (PPIP5Ks), regulate phosphate homeostasis, ATP synthesis, and several other metabolic processes ranging from insulin secretion to cellular energy utilization. Here, we review the current understanding of the catalytic and regulatory mechanisms of IP6Ks and PPIP5Ks, as well as their counteracting phosphatases. We also highlight the genetic and cellular evidence implicating inositol pyrophosphates as essential mediators of mammalian metabolic homeostasis.

The significance of electrical signals in maturing spermatozoa for phosphoinositide regulation through voltage-sensing phosphatase.

Voltage-sensing phosphatase (VSP) exhibits voltage-dependent phosphatase activity toward phosphoinositides. VSP generates a specialized phosphoinositide environment in mammalian sperm flagellum. However, the voltage-sensing mechanism of VSP in spermatozoa is not yet characterized. Here, we found that VSP is activated during sperm maturation, indicating that electric signals in immature spermatozoa are essential. Using a heterologous expression system, we show the voltage-sensing property of mouse VSP (mVSP). The voltage-sensing threshold of mVSP is approximately -30 mV, which is sensitive enough to activate mVSP in immature spermatozoa. We also report several knock-in mice in which we manipulate the voltage-sensitivity or electrochemical coupling of mVSP. Notably, the V312R mutant, with a minor voltage-sensitivity change, exhibits abnormal sperm motility after, but not before, capacitation. Additionally, the V312R mutant shows a significant change in the acyl-chain profile of phosphoinositide. Our findings suggest that electrical signals during sperm maturation are crucial for establishing the optimal phosphoinositide environment in spermatozoa.

Control of lysogeny and antiphage defense by a prophage-encoded kinase-phosphatase module.

The filamentous 'Pf' bacteriophages of Pseudomonas aeruginosa play roles in biofilm formation and virulence, but mechanisms governing Pf prophage activation in biofilms are unclear. Here, we identify a prophage regulatory module, KKP (kinase-kinase-phosphatase), that controls virion production of co-resident Pf prophages and mediates host defense against diverse lytic phages. KKP consists of Ser/Thr kinases PfkA and PfkB, and phosphatase PfpC. The kinases have multiple host targets, one of which is MvaU, a host nucleoid-binding protein and known prophage-silencing factor. Characterization of KKP deletion and overexpression strains with transcriptional, protein-level and prophage-based approaches indicates that shifts in the balance between kinase and phosphatase activities regulate phage production by controlling MvaU phosphorylation. In addition, KKP acts as a tripartite toxin-antitoxin system that provides defense against some lytic phages. A conserved lytic phage replication protein inhibits the KKP phosphatase PfpC, stimulating toxic kinase activity and blocking lytic phage production. Thus, KKP represents a phosphorylation-based mechanism for prophage regulation and antiphage defense. The conservation of KKP gene clusters in >1000 diverse temperate prophages suggests that integrated control of temperate and lytic phage infection by KKP-like regulatory modules may play a widespread role in shaping host cell physiology.

Transcriptional upregulation of the myo-inositol biosynthesis pathway is enhanced by NFAT5 in hyperosmotically stressed tilapia cells.

Euryhaline fish experience variable osmotic environments requiring physiological adjustments to tolerate elevated salinity. Mozambique tilapia (Oreochromis mossambicus) possess one of the highest salinity tolerance limits of any fish. In tilapia and other euryhaline fish species, the myo-inositol biosynthesis (MIB) pathway enzymes, myo-inositol phosphate synthase (MIPS) and inositol monophosphatase 1 (IMPA1.1), are among the most upregulated mRNAs and proteins indicating the high importance of this pathway for hyperosmotic (HO) stress tolerance. These abundance changes must be precluded by HO perception and signaling mechanism activation to regulate the expression of MIPS and IMPA1.1 genes. In previous work using a O. mossambicus cell line (OmB), a reoccurring osmosensitive enhancer element (OSRE1) in both MIPS and IMPA1.1 was shown to transcriptionally upregulate these enzymes in response to HO stress. The OSRE1 core consensus (5'-GGAAA-3') matches the core binding sequence of the predominant mammalian HO response transcription factor, nuclear factor of activated T-cells (NFAT5). HO-challenged OmB cells showed an increase in NFAT5 mRNA suggesting NFAT5 may contribute to MIB pathway regulation in euryhaline fish. Ectopic expression of wild-type NFAT5 induced an IMPA1.1 promoter-driven reporter by 5.1-fold (P < 0.01). Moreover, expression of dominant negative NFAT5 in HO media resulted in a 47% suppression of the reporter signal (P < 0.005). Furthermore, reductions of IMPA1.1 (37-49%) and MIPS (6-37%) mRNA abundance were observed in HO-challenged NFAT5 knockout cells relative to control cells. Collectively, these multiple lines of experimental evidence establish NFAT5 as a tilapia transcription factor contributing to HO-induced activation of the MIB pathway.NEW & NOTEWORTHY In our study, we use a multi-pronged synthetic biology approach to demonstrate that the fish homolog of the predominant mammalian osmotic stress transcription factor nuclear factor of activated T-cells (NFAT5) also contributes to the activation of hyperosmolality inducible genes in cells of extremely euryhaline fish. However, in addition to NFAT5 the presence of other strong osmotically inducible signaling mechanisms is required for full activation of osmoregulated tilapia genes.

Sac1 links phosphoinositide turnover to cryptococcal virulence.

Cryptococcus neoformans is an environmentally acquired fungal pathogen that causes over 140,000 deaths per year. Cryptococcal infection occurs when infectious particles are deposited into the lung, where they encounter host phagocytic cells. C. neoformans may be engulfed by these phagocytes, an important step of infection that leads to outcomes ranging from termination of infection to cryptococcal dissemination. To study this critical process, we screened approximately 4,700 cryptococcal gene deletion mutants for altered uptake, using primary mouse and human phagocytic cells. Among the hits of these two screens, we identified 93 mutants with perturbed uptake in both systems, as well as others with differences in uptake by only one cell type. We further screened the hits for changes in thickness of the capsule, a protective polysaccharide layer around the cell which is an important cryptococcal virulence factor. The combination of our three screens yielded 45 mutants, including one lacking the phosphatidylinositol-4-phosphate phosphatase Sac1. In this work, we implicate Sac1 in both host cell uptake and capsule production. We found that sac1 mutants exhibit lipid trafficking defects, reductions in secretory system function, and changes in capsule size and composition. Many of these changes occur specifically in tissue culture media, highlighting the role of Sac1 phosphatase activity in responding to the stress of host-like conditions. Overall, these findings show how genome-scale screening can identify cellular factors that contribute to our understanding of cryptococcal biology and demonstrate the role of Sac1 in determining fungal virulence.IMPORTANCECryptococcus neoformans is a fungal pathogen with significant impact on global health. Cryptococcal cells inhaled from the environment are deposited into the lungs, where they first contact the human immune system. The interaction between C. neoformans and host cells is critical because this step of infection can determine whether the fungal cells die or proliferate within the human host. Despite the importance of this stage of infection, we have limited knowledge of cryptococcal factors that influence its outcome. In this study, we identify cryptococcal genes that affect uptake by both human and mouse cells. We also identify mutants with altered capsule, a protective coating that surrounds the cells to shield them from the host immune system. Finally, we characterize the role of one gene, SAC1, in these processes. Overall, this study contributes to our understanding of how C. neoformans interacts with and protects itself from host cells.

Involvement of 2-deoxyglucose-6-phosphate phosphatases in facilitating resilience against ionic and osmotic stress in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae DOG genes, DOG1 and DOG2, encode for 2-deoxyglucose-6-phosphate phosphatases. These enzymes of the haloacid dehalogenase superfamily are known to utilize the non-natural 2-deoxyglucose-6-phosphate as their substrate. However, their physiological substrate and hence their biological role remain elusive. In this study, we investigated their potential role as enzymes in biosynthesizing glycerol through an alternative pathway, which involves the dephosphorylation of dihydroxyacetone phosphate into dihydroxyacetone, as opposed to the classical pathway which utilizes glycerol 3-phosphate. Overexpression of DOG1 or DOG2 rescued the osmotic and ionic stress-sensitive phenotype of gpp1∆ gpp2∆ or gpd1∆ gpd2∆ mutants, both affected in the production of glycerol. While small amounts of glycerol were observed in the DOG overexpression strains in the gpp1∆ gpp2∆ background, no glycerol was detected in the gpd1∆ gpd2∆ mutant background. This indicates that overexpression of the DOG enzymes can rescue the osmosensitive phenotype of the gpd1∆ gpd2∆ mutant independent of glycerol production. We also did not observe a drop in glycerol levels in the gpp1∆ gpp2∆ dog1∆ dog2∆ as compared to the gpp1∆ gpp2∆ mutant, indicating that the Dog enzymes are not involved in glycerol biosynthesis. This indicates that Dog enzymes have a distinct substrate and their function within the cell remains undiscovered. IMPORTANCE: Yeast stress tolerance is an important characteristic that is studied widely, not only regarding its fundamental insights but also for its applications within the biotechnological industry. Here, we investigated the function of two phosphatase encoding genes, DOG1 and DOG2, which are induced as part of the general stress response pathway, but their natural substrate in the cells remains unclear. They are known to dephosphorylate the non-natural substrate 2-deoxyglucose-6-phosphate. Here, we show that overexpression of these genes overcomes the osmosensitive phenotype of mutants that are unable to produce glycerol. However, in these overexpression strains, very little glycerol is produced indicating that the Dog enzymes do not seem to be involved in a previously predicted alternative pathway for glycerol production. Our work shows that overexpression of the DOG genes may improve osmotic and ionic stress tolerance in yeast.

Grain-Boundary-Rich Ceria Metallene Nanozyme with Abundant Metal Site Pairs Boosts Phosphatase-like Activity.

Natural phosphatases featuring paired metal sites inspire various advanced nanozymes with phosphatase-like activity as alternatives in practical applications. Numerous efforts to create point defects show limited metal site pairs, further resulting in insufficient activity. However, it remains a grand challenge to accurately engineer abundant metal site pairs in nanozymes. Herein, we report a grain-boundary-rich ceria metallene nanozyme (GB-CeO2) with phosphatase-like activity. Grain boundaries acting as the line or interfacial defects can effectively increase the content of Ce4+/Ce3+ site pairs to 72.28%, achieving a 49.28-fold enhancement in activity. Furthermore, abundant grain boundaries optimize the band structure to assist the photoelectron transfer under irradiation, which further increases the content of metal site pairs to 88.96% and finally realizes a 114.39-fold enhanced activity over that of CeO2 without irradiation. Given the different inhibition effects of pesticides on catalysts with and without irradiation, GB-CeO2 was successfully applied to recognize mixed toxic pesticides.

Evolutionary history and root trait coordination predict nutrient strategy in tropical legume trees.

Plants express diverse nutrient use and acquisition traits, but it is unclear how trait combinations at the species level are constrained by phylogeny, trait coordination, or trade-offs in resource investment. One trait - nitrogen (N) fixation - is assumed to correlate with other traits and used to define plant functional groups, despite potential confounding effects of phylogeny. We quantified growth, carbon metabolism, fixation rate, root phosphatase activity (RPA), mycorrhizal colonization, and leaf and root morphology/chemistry across 22 species of fixing and nonfixing tropical Fabaceae trees under common conditions. Belowground trait variation was high even among closely related species, and most traits displayed a phylogenetic signal, including N-fixation rate and nodule biomass. Across species, we observed strong positive correlations between physiological traits such as RPA and root respiration. RPA increased ~ fourfold per unit increase in fixation, supporting the debated hypothesis that N-fixers 'trade' N for phosphatases to enhance phosphorus acquisition. Specific root length and root N differed between functional groups, though for other traits, apparent differences became nonsignificant after accounting for phylogenetic nonindependence. We conclude that evolutionary history, trait coordination, and fixation ability contribute to nutrient trait expression at the species level, and recommend explicitly considering phylogeny in analyses of functional groupings.

USP9X regulates the proliferation, survival, migration and invasion of gastric cancer cells by stabilizing MTH1.

BACKGROUND: MutT homolog 1 (MTH1) sanitizes oxidized dNTP pools to promote the survival of cancer cells and its expression is frequently upregulated in cancers. Polyubiquitination stabilizes MTH1 to facilitate the proliferation of melanoma cells, suggesting the ubiquitin system controls the stability and function of MTH1. However, whether ubiquitination regulates MTH1 in gastric cancers has not been well defined. This study aims to investigate the interaction between MTH1 and a deubiquitinase, USP9X, in regulating the proliferation, survival, migration, and invasion of gastric cancer cells. METHODS: The interaction between USP9X and MTH1 was evaluated by co-immunoprecipitation (co-IP) in HGC-27 gastric cancer cells. siRNAs were used to interfere with USP9X expression in gastric cancer cell lines HGC-27 and MKN-45. MTT assays were carried out to examine the proliferation, propidium iodide (PI) and 7-AAD staining assays were performed to assess the cell cycle, Annexin V/PI staining assays were conducted to examine the apoptosis, and transwell assays were used to determine the migration and invasion of control, USP9X-deficient, and USP9X-deficient plus MTH1-overexpressing HGC-27 and MKN-45 gastric cancer cells. RESULTS: Co-IP data show that USP9X interacts with and deubiquitinates MTH1. Overexpression of USP9X elevates MTH1 protein level by downregulating its ubiquitination, while knockdown of USP9X has the opposite effect on MTH1. USP9X deficiency in HGC-27 and MKN-45 cells causes decreased proliferation, cell cycle arrest, extra apoptosis, and defective migration and invasion, which could be rescued by excessive MTH1. CONCLUSION: USP9X interacts with and stabilizes MTH1 to promote the proliferation, survival, migration and invasion of gastric cancer cells.

[Effects of inhibitors of DNA repair enzymes OGG1 and MTH1 on the replication of African swine fever virus].

African swine fever virus (ASFV), as a contagious viral pathogen, is responsible for the occurrence of African swine fever (ASF), a rapidly spreading and highly lethal disease. Since ASFV was introduced into China in 2018, it has been quickly spread to many provinces, which brought great challenges to the pig industry in China. Due to the limited knowledge about the pathogenesis of ASFV, neither vaccines nor antiviral drugs are available. We have found that ASFV infection can induce oxidative stress responses in cells, and DNA repair enzymes play a key role in this process. This study employed RNA interference, RT-qPCR, Western blotting, Hemadsorption (HAD), and flow cytometry to investigate the effects of the inhibitors of DNA repair enzymes OGG1 and MTH1 on ASFV replication and evaluated the anti-ASFV effects of the inhibitors. This study provides reference for the development of anti-viral drugs.

Histidine Phosphorylation: Protein Kinases and Phosphatases.

Phosphohistidine (pHis) is a reversible protein post-translational modification (PTM) that is currently poorly understood. The P-N bond in pHis is heat and acid-sensitive, making it more challenging to study than the canonical phosphoamino acids pSer, pThr, and pTyr. As advancements in the development of tools to study pHis have been made, the roles of pHis in cells are slowly being revealed. To date, a handful of enzymes responsible for controlling this modification have been identified, including the histidine kinases NME1 and NME2, as well as the phosphohistidine phosphatases PHPT1, LHPP, and PGAM5. These tools have also identified the substrates of these enzymes, granting new insights into previously unknown regulatory mechanisms. Here, we discuss the cellular function of pHis and how it is regulated on known pHis-containing proteins, as well as cellular mechanisms that regulate the activity of the pHis kinases and phosphatases themselves. We further discuss the role of the pHis kinases and phosphatases as potential tumor promoters or suppressors. Finally, we give an overview of various tools and methods currently used to study pHis biology. Given their breadth of functions, unraveling the role of pHis in mammalian systems promises radical new insights into existing and unexplored areas of cell biology.