RESUMEN

LHPP, a novel, recognized tumor suppressor, exerts a critical influence on the regulation of tumor cell proliferation and survival by modulating various signaling pathways with its phosphatase activity. Here, we unveil a robust correlation between reduced LHPP expression and adverse prognosis in prostate cancer. We demonstrate that LHPP interacts with AKT, thereby dampening AKT phosphorylation and subsequently inhibiting ACSL4 phosphorylation at the T624 site. This interaction impedes phosphorylation-dependent ubiquitination, thwarting SKP2 from recognizing and binding to ACSL4 at the K621 site. As a result, ACSL4 is spared from lysosomal degradation, leading to its accumulation and the promotion of lipid peroxidation, and ferroptosis. Moreover, our findings reveal that Panobinostat, a potent histone-deacetylase inhibitor, intricately regulates LHPP expression at multiple levels through the inhibition of HDAC3. This complex modulation enhances the ferroptosis pathway, offering a novel mechanism for curtailing the growth of prostate tumors and highlighting its significant translational potential for clinical application.

Asunto(s)

Coenzima A Ligasas , Ferroptosis , Neoplasias de la Próstata , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Masculino , Ferroptosis/efectos de los fármacos , Humanos , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/efectos de los fármacos , Coenzima A Ligasas/metabolismo , Línea Celular Tumoral , Animales , Fosforilación , Ratones , Histona Desacetilasas/metabolismo , Ratones Desnudos , Pirofosfatasa Inorgánica

RESUMEN

Plants have developed precise defense mechanisms against cadmium (Cd) stress, with vacuolar compartmentalization of Cd2+ being a crucial process in Cd detoxification. The transport of Cd into vacuoles by these cation / H+ antiporters is powered by the pH gradient created by proton pumps. In this study, the full-length cDNA of a vacuolar H+-pyrophosphatase (V-PPase) gene from Boehmeria nivea (ramie), BnVP1, was isolated using the rapid amplification of cDNA ends (RACE) method. The open reading frame (ORF) of BnVP1 is 2292 bp, encoding a 763 amino acid V-PPase protein with 15 predicted transmembrane domains. Sequence alignment and phylogenetic analysis revealed that BnVP1 belongs to the Type I V-PPase family. Quantitative RT-PCR assays demonstrated that BnVP1 expression was significantly higher in ramie roots than in shoots. Cd treatments markedly induced BnVP1 expression in both roots and leaves of ramie seedlings, with a more pronounced effect in roots. Additionally, BnVP1 expression was significantly upregulated by the plant hormone methyl jasmonate (MeJA). Heterologous expression of BnVP1 in transgenic Arabidopsis significantly enhanced V-PPase activity in the roots. The growth performance, root elongation, and total chlorophyll content of transgenic plants with high tonoplast H+-PPase (V-PPase) activity were superior to those of wild-type plants. Overexpression of BnVP1 reduced membrane lipid peroxidation and ion leakage, and significantly increased Cd accumulation in the roots of transgenic Arabidopsis seedlings. This study provides new genetic resources for the phytoremediation of Cd-contaminated farmland.

Asunto(s)

Arabidopsis , Boehmeria , Cadmio , Regulación de la Expresión Génica de las Plantas , Pirofosfatasa Inorgánica , Filogenia , Plantas Modificadas Genéticamente , Vacuolas , Arabidopsis/genética , Cadmio/metabolismo , Cadmio/toxicidad , Plantas Modificadas Genéticamente/genética , Pirofosfatasa Inorgánica/genética , Pirofosfatasa Inorgánica/metabolismo , Vacuolas/metabolismo , Boehmeria/genética , Boehmeria/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/efectos de los fármacos , Secuencia de Aminoácidos , Ciclopentanos/farmacología , Ciclopentanos/metabolismo , Oxilipinas/farmacología , Oxilipinas/metabolismo , Acetatos

RESUMEN

Background: Recently, the role of inorganic pyrophosphatase 2 (PPA2) has been remaining merely superficial in many tumors. Hence, the aim was to analyze the potential functions of PPA2 in pan-cancer, focusing on its role in breast cancer. Methods: A systematic pan-cancer analysis conducted primarily utilizing various open databases such as TCGA and GTEx. We explored the clinical value of PPA2 as well as various biological functions, including expression levels and subcellular localization, multi-dimensional immune-correlation analysis, co-expression networks, and gene heterogeneity. In addition, we not only verified the function of PPA2 through cell experiments but also analyzed PPA2 at the single-cell level and its drug sensitivity. Results: PPA2 is abnormally expressed in various tumors, and it is mainly distributed in mitochondria. Furthermore, the indicators (OS, DSS, DFI, and PFI) of analysis hint that PPA2 exhibits significant prognostic value. At the same time, the genomic heterogeneity (including TMB, MSI, MATH, and NEO) of PPA2 in pan-cancer was analyzed. Across multiple tumors, the results showed a close correlation between PPA2 expression levels and different immune signatures (such as immune cell infiltration). All of these indicate that PPA2 could potentially be applied in the guidance of immunotherapy. We also have demonstrated that PPA2 promoted the process of breast cancer. Finally, some potential therapeutic agents (such as Fulvestrant) targeting the abnormal expression of PPA2 are revealed. Conclusion: In conclusion, the results demonstrated the great value of PPA2 in pan-cancer research, as well as its potential as a therapeutic target for breast tumors.

Asunto(s)

Biomarcadores de Tumor , Neoplasias de la Mama , Pirofosfatasa Inorgánica , Humanos , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/genética , Neoplasias de la Mama/diagnóstico , Femenino , Pronóstico , Biomarcadores de Tumor/genética , Pirofosfatasa Inorgánica/genética , Pirofosfatasa Inorgánica/metabolismo , Regulación Neoplásica de la Expresión Génica , Microambiente Tumoral/inmunología , Microambiente Tumoral/genética , Perfilación de la Expresión Génica , Línea Celular Tumoral , Multiómica

RESUMEN

Dissolution dynamic nuclear polarization (d-DNP) has enabled applications such as the real-time monitoring of chemical reactions. Such applications are mainly for 13C and 15N spins with long spin-lattice relaxation times in the molecules of interest. However, the only applications for phosphorus using d-DNP are pH imaging and nucleation during crystallization due to the short relaxation times. Here we show that it is possible to observe enzyme reactions using d-DNP with phosphorus. Hyperpolarized 31P spins in pyrophosphate were obtained using bullet-DNP, which requires less dilution of highly polarized solid samples. Real-time monitoring of the hydrolysis reaction of pyrophosphate by inorganic pyrophosphatase from baker's yeast at physiological pH and was successfully achieved and the reaction rate was determined. This is an important reaction for a wide range of applications related to medicine, agriculture, and quantum life science.

Asunto(s)

Difosfatos , Pirofosfatasa Inorgánica , Hidrólisis , Difosfatos/química , Pirofosfatasa Inorgánica/química , Pirofosfatasa Inorgánica/metabolismo , Saccharomyces cerevisiae/química , Concentración de Iones de Hidrógeno , Espectroscopía de Resonancia Magnética/métodos

RESUMEN

Regulatory cystathionine ß-synthase (CBS) domains are widespread in proteins; however, difficulty in structure determination prevents a comprehensive understanding of the underlying regulation mechanism. Tetrameric microbial inorganic pyrophosphatase containing such domains (CBS-PPase) is allosterically inhibited by AMP and ADP and activated by ATP and cell alarmones diadenosine polyphosphates. Each CBS-PPase subunit contains a pair of CBS domains but binds cooperatively to only one molecule of the mono-adenosine derivatives. We used site-directed mutagenesis of Desulfitobacterium hafniense CBS-PPase to identify the key elements determining the direction of the effect (activation or inhibition) and the "half-of-the-sites" ligand binding stoichiometry. Seven amino acid residues were selected in the CBS1 domain, based on the available X-ray structure of the regulatory domains, and substituted by alanine and other residues. The interaction of 11 CBS-PPase variants with the regulating ligands was characterized by activity measurements and isothermal titration calorimetry. Lys100 replacement reversed the effect of ADP from inhibition to activation, whereas Lys95 and Gly118 replacements made ADP an activator at low concentrations but an inhibitor at high concentrations. Replacement of these residues for alanine increased the stoichiometry of mono-adenosine phosphate binding by twofold. These findings identified several key protein residues and suggested a "two non-interacting pairs of interacting regulatory sites" concept in CBS-PPase regulation.

Asunto(s)

Cistationina betasintasa , Cistationina betasintasa/metabolismo , Cistationina betasintasa/química , Cistationina betasintasa/genética , Mutación , Unión Proteica , Mutagénesis Sitio-Dirigida , Nucleótidos de Adenina/metabolismo , Nucleótidos de Adenina/química , Dominios Proteicos , Pirofosfatasas/metabolismo , Pirofosfatasas/química , Pirofosfatasas/genética , Adenosina Difosfato/metabolismo , Adenosina Trifosfato/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Pirofosfatasa Inorgánica/metabolismo , Pirofosfatasa Inorgánica/química , Pirofosfatasa Inorgánica/genética , Modelos Moleculares , Sitios de Unión

RESUMEN

Pyrophosphatases (PPases) are enzymes that catalyze the hydrolysis of pyrophosphate (PPi), a byproduct of the synthesis and degradation of diverse biomolecules. The accumulation of PPi in the cell can result in cell death. Although the substrate is the same, there are variations in the catalysis and features of these enzymes. Two enzyme forms have been identified in bacteria: cytoplasmic or soluble pyrophosphatases and membrane-bound pyrophosphatases, which play major roles in cell bioenergetics. In eukaryotic cells, cytoplasmic enzymes are the predominant form of PPases (c-PPases), while membrane enzymes (m-PPases) are found only in protists and plants. The study of bacterial cytoplasmic and membrane-bound pyrophosphatases has slowed in recent years. These enzymes are central to cell metabolism and physiology since phospholipid and nucleic acid synthesis release important amounts of PPi that must be removed to allow biosynthesis to continue. In this review, two aims were pursued: first, to provide insight into the structural features of PPases known to date and that are well characterized, and to provide examples of enzymes with novel features. Second, the scientific community should continue studying these enzymes because they have many biotechnological applications. Additionally, in this review, we provide evidence that there are m-PPases present in fungi; to date, no examples have been characterized. Therefore, the diversity of PPase enzymes is still a fruitful field of research. Additionally, we focused on the roles of H+/Na+ pumps and m-PPases in cell bioenergetics. Finally, we provide some examples of the applications of these enzymes in molecular biology and biotechnology, especially in plants. This review is valuable for professionals in the biochemistry field of protein structure-function relationships and experts in other fields, such as chemistry, nanotechnology, and plant sciences.

Asunto(s)

Bacterias , Pirofosfatasa Inorgánica , Pirofosfatasa Inorgánica/metabolismo , Pirofosfatasa Inorgánica/química , Pirofosfatasa Inorgánica/genética , Bacterias/enzimología , Hongos/enzimología , Difosfatos/metabolismo , Difosfatos/química

RESUMEN

Inositol pyrophosphate 1,5-IP8 regulates expression of a fission yeast phosphate homeostasis regulon, comprising phosphate acquisition genes pho1, pho84, and tgp1, via its action as an agonist of precocious termination of transcription of the upstream lncRNAs that repress PHO mRNA synthesis. 1,5-IP8 levels are dictated by a balance between the Asp1 N-terminal kinase domain that converts 5-IP7 to 1,5-IP8 and three inositol pyrophosphatases-the Asp1 C-terminal domain (a histidine acid phosphatase), Siw14 (a cysteinyl-phosphatase), and Aps1 (a Nudix enzyme). In this study, we report the biochemical and genetic characterization of Aps1 and an analysis of the effects of Asp1, Siw14, and Aps1 mutations on cellular inositol pyrophosphate levels. We find that Aps1's substrate repertoire embraces inorganic polyphosphates, 5-IP7, 1-IP7, and 1,5-IP8. Aps1 displays a ~twofold preference for hydrolysis of 1-IP7 versus 5-IP7 and aps1∆ cells have twofold higher levels of 1-IP7 vis-à-vis wild-type cells. While neither Aps1 nor Siw14 is essential for growth, an aps1∆ siw14∆ double mutation is lethal on YES medium. This lethality is a manifestation of IP8 toxicosis, whereby excessive 1,5-IP8 drives derepression of tgp1, leading to Tgp1-mediated uptake of glycerophosphocholine. We were able to recover an aps1∆ siw14∆ mutant on ePMGT medium lacking glycerophosphocholine and to suppress the severe growth defect of aps1∆ siw14∆ on YES by deleting tgp1. However, the severe growth defect of an aps1∆ asp1-H397A strain could not be alleviated by deleting tgp1, suggesting that 1,5-IP8 levels in this double-pyrophosphatase mutant exceed a threshold beyond which overzealous termination affects other genes, which results in cytotoxicity. IMPORTANCE: Repression of the fission yeast PHO genes tgp1, pho1, and pho84 by lncRNA-mediated interference is sensitive to changes in the metabolism of 1,5-IP8, a signaling molecule that acts as an agonist of precocious lncRNA termination. 1,5-IP8 is formed by phosphorylation of 5-IP7 and catabolized by inositol pyrophosphatases from three distinct enzyme families: Asp1 (a histidine acid phosphatase), Siw14 (a cysteinyl phosphatase), and Aps1 (a Nudix hydrolase). This study entails a biochemical characterization of Aps1 and an analysis of how Asp1, Siw14, and Aps1 mutations impact growth and inositol pyrophosphate pools in vivo. Aps1 catalyzes hydrolysis of inorganic polyphosphates, 5-IP7, 1-IP7, and 1,5-IP8 in vitro, with a ~twofold preference for 1-IP7 over 5-IP7. aps1∆ cells have twofold higher levels of 1-IP7 than wild-type cells. An aps1∆ siw14∆ double mutation is lethal because excessive 1,5-IP8 triggers derepression of tgp1, leading to toxic uptake of glycerophosphocholine.

Asunto(s)

Pirofosfatasas , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Schizosaccharomyces/genética , Schizosaccharomyces/enzimología , Schizosaccharomyces/metabolismo , Schizosaccharomyces/crecimiento & desarrollo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Pirofosfatasas/genética , Pirofosfatasas/metabolismo , Pirofosfatasa Inorgánica/metabolismo , Pirofosfatasa Inorgánica/genética , Fosfatos de Inositol/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo , Monoéster Fosfórico Hidrolasas/genética , Regulación Fúngica de la Expresión Génica , Mutación , Hidrolasas Nudix , Enzimas Multifuncionales

RESUMEN

Hepatocellular carcinoma (HCC) is the most common primary liver cancer worldwide and no pharmacological treatment is available that can achieve complete remission of HCC. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) is a recently identified HCC tumor suppressor gene which plays an important role in the development of HCC and its inactivation and reactivation has been shown to result in respectively HCC tumorigenesis and suppression. Small activating RNAs (saRNAs) have been used to achieve targeted activation of therapeutic genes for the restoration of their encoded protein through the RNAa mechanism. Here we designed and validated saRNAs that could activate LHPP expression at both the mRNA and protein levels in HCC cells. Activation of LHPP by its saRNAs led to the suppression of HCC proliferation, migration and the inhibition of Akt phosphorylation. When combined with targeted anticancer drugs (e.g., regorafenib), LHPP saRNA exhibited synergistic effect in inhibiting in vitro HCC proliferation and in vivo antitumor growth in a xenograft HCC model. Findings from this study provides further evidence for a tumor suppressor role of LHPP and potential therapeutic value of restoring the expression of LHPP by saRNA for the treatment of HCC.

Asunto(s)

Carcinoma Hepatocelular , Proliferación Celular , Pirofosfatasa Inorgánica , Neoplasias Hepáticas , Humanos , Pirofosfatasa Inorgánica/metabolismo , Pirofosfatasa Inorgánica/genética , Proliferación Celular/efectos de los fármacos , Animales , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/genética , Ratones , Línea Celular Tumoral , Regulación hacia Arriba/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Movimiento Celular/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Ratones Desnudos

RESUMEN

Fenton chemistry has aroused widespread concern due to its application in the green oxidation and mineralization of organic wastes. Inorganic pyrophosphatase (PPase) catalyzes the hydrolysis of pyrophosphate ions (PPi) and provides a thermodynamic driving force for many biosynthetic reactions. Fluoride (F-) is widely applied to fight against tooth decay and reduce cavities. The electrochemical determination of PPase activity and F- was realized based on Fenton chemistry in this work. Glassy carbon electrode modified with poly (azure A) and acetylene black (GCE/PAA-AB) was fabricated. Hydroxyl radicals (∙OH) that were generated from a Cu2+-catalyzed Fenton-type reaction could oxidize PAA in the near-neutral medium, leading to a great increase of the cathodic peak current (Ipc). A coordination reaction between PPi and Cu2+ exerted a negative effect on Fenton reaction and hindered the Ipc enhancement. Cu2+-PPi complex was decomposed due to the hydrolysis of PPi induced by PPase, which caused the reappearance of the notably increased current response. F- could effectively inhibit PPase activity. As a result, the stable Cu2+-PPi complex remained and the high Ipc suffered from the decline again. The Ipc difference was used for the highly sensitive determination of PPase activity in the content range of 0.001-20 mU mL-1 with a detection of limit (LOD) at 0.6 µU mL-1 and that of F- in the concentration range of 0.01-100 µM with a LOD at 7 nM. The proposed PPase and F- sensor displayed a good selectivity, stability and reproducibility, and a high accuracy.

Asunto(s)

Técnicas Electroquímicas , Fluoruros , Hierro , Fluoruros/química , Hierro/química , Técnicas Electroquímicas/métodos , Peróxido de Hidrógeno/química , Peróxido de Hidrógeno/metabolismo , Cobre/química , Electrodos , Pirofosfatasas/metabolismo , Pirofosfatasas/análisis , Pirofosfatasa Inorgánica/metabolismo , Pirofosfatasa Inorgánica/química , Límite de Detección , Pruebas de Enzimas/métodos

RESUMEN

Biallelic variants in PPA2 gene cause a rare but lethal mitochondrial disorder. We describe the first four cases reported in Spain of PPA2 disease in two unrelated families. We have conducted a revision of the clinical history, necropsies, and postmortem genetic testing from probands, and clinical evaluation, genetic testing and blood transcript analysis in family members. All the cases harbored biallelic PPA2 variants in compound heterozygous status. Two brothers from family 1 suffered sudden death after a small first intake of alcohol in 2013 and 2022. The sister remains alive but affected with cardiomyopathy, extensive scar on cardiac imaging, and high sensitivity to alcohol intake. The three siblings carried PPA2 c.290A > G (p.Glu97Gly) novel missense variant and PPA2 c.513C > T (p.Cys171 = ) altering splicing site variant, both probably leading to mRNA degradation based on in-silico and transcript analyses. A teenager from family 2 suffered sudden death after a small intake of alcohol in 2018 and carried PPA2 c.683C > T (p.Pro228Leu) missense and PPA2 c.980_983del (p.Gln327fs) novel frameshift variant, both probably leading to abnormal protein structure. All cases were asymptomatic until adolescence. Furthermore, the sister in family 1 has survived as an asymptomatic adult. PPA2 disease can manifest as cardiac arrest in the young, especially after alcohol exposure. Our results show that PPA2 deficiency can be related to different pathogenicity mechanisms such as abnormal protein structure but also mRNA decay caused by synonymous or missense variants. Strict avoidance of alcohol consumption and early defibrillator implantation might prevent lethal arrhythmias in patients at risk.

Asunto(s)

Consumo de Bebidas Alcohólicas , Muerte Súbita Cardíaca , Pirofosfatasa Inorgánica , Proteínas Mitocondriales , Adolescente , Adulto , Femenino , Humanos , Masculino , Consumo de Bebidas Alcohólicas/genética , Consumo de Bebidas Alcohólicas/efectos adversos , Muerte Súbita Cardíaca/etiología , Mutación Missense , Linaje , España , Proteínas Mitocondriales/genética , Pirofosfatasa Inorgánica/genética

RESUMEN

BACKGROUND: Inorganic pyrophosphatase (PPase) is key enzyme playing a key role in biochemical transformations such as biosynthesis of DNA and RNA, bone formation, metabolic pathways associated with lipid, carbohydrate and phosphorous. It has been reported that lung adenocarcinomas, colorectal cancer, and hyperthyroidism disorders can result from abnormal level of PPase. Therefore, it is of notable significance to develop simple and effective real time assay for PPase enzyme activity monitoring for screening of many metabolic pathways as well as for early disease diagnosis. RESULT: The fluorometric detection of PPase enzyme in near infrared region-1 (NIR-1) has been carried out using bimetallic nanoclusters (LA@AuAg NCs). The developed sensing strategy was based on quenching of fluorescence intensity of LA@AuAg NCs upon interaction with copper (Cu2+) ions. The off state of LA@AuAg_Cu2+ ensemble was turned on upon addition of pyrophosphate anion (PPi) due to strong binding interaction between PPi and Cu2+. The catalytic conversion of PPi into phosphate anion (Pi) in the presence of PPase led to liberation of Cu2+ ions, and again quenched off state was retrieved due to interaction of free Cu2+ with LA@AuAg NCs. The ultrasensitive detection of PPase was observed in the linear range of 0.06-250 mU/mL with LOD as 0.0025 mU/mL. The designed scheme showed good selectivity towards PPase enzyme in comparison to other bio-substrates, along with good percentage recovery for PPase detection in real human serum samples. SIGNIFICANCE: The developed NIR based assay is ultrasensitive, highly selective and robust for PPase enzyme and can be safely employed for other enzymes detection. This highly sensitive nature of biosensor was result of involvement of fluorescence-based technique and synergistic effect of dual metal in NIR based bimetallic NCs. Moreover, owing to the emission in NIR domain, in future, these nanoclusters can be safely employed for many biomedical applications for In vivo studies.

Asunto(s)

Cobre , Difosfatos , Fluorometría , Oro , Pirofosfatasa Inorgánica , Nanopartículas del Metal , Plata , Cobre/química , Oro/química , Pirofosfatasa Inorgánica/metabolismo , Pirofosfatasa Inorgánica/química , Plata/química , Nanopartículas del Metal/química , Fluorometría/métodos , Difosfatos/química , Humanos , Límite de Detección , Rayos Infrarrojos

RESUMEN

Inorganic pyrophosphatases (PPases) are enzymes that catalyze the conversion of inorganic pyrophosphate (PPi) into phosphate (Pi). Human inorganic pyrophosphatase 1 (Hu-PPase) exhibits high expression levels in a variety of tumors and plays roles in cell proliferation, apoptosis, invasion and metastasis, making it a promising prognostic biomarker and a target for cancer therapy. Despite its widespread presence, the catalytic mechanism of Hu-PPase in humans remains inadequately understood. The signature motif amino acid sequence (DXDPXD) within the active sites of PPases is preserved across different species. In this research, an enzymatic activity assay revealed that mutations led to a notable reduction in enzymatic function, although the impact of the four amino acids on the activity of the pocket varied. To investigate the influence of these residues on the substrate binding and enzymatic function of PPase, the crystal structure of the Hu-PPase-ED quadruple mutant (D116A/D118A/P119A/D121A) was determined at 1.69 Å resolution. The resulting structure maintained a barrel-like shape similar to that of the wild-type, albeit lacking Mg2+ ions. Molecular docking analysis demonstrated a decreased ability of Hu-PPase-ED to bind to PPi. Further, molecular dynamics simulation analysis indicated that the mutation rendered the loop of Mg2+ ion-binding residues less stable. Therefore, the effect on enzyme activity did not result from a change in the gross protein structure but rather from a mutation that abolished the Mg2+-coordinating groups, thereby eliminating Mg2+ binding and leading to the loss of enzyme activity.

Asunto(s)

Pirofosfatasa Inorgánica , Pirofosfatasas , Humanos , Secuencia de Aminoácidos , Dominio Catalítico , Pirofosfatasa Inorgánica/química , Pirofosfatasa Inorgánica/genética , Simulación del Acoplamiento Molecular , Pirofosfatasas/química , Pirofosfatasas/genética

RESUMEN

14-3-3 proteins are widely distributed in eukaryotic cells and play an important role in plant growth, development, and stress tolerance. This study revealed nine 14-3-3 genes from the genome of Nitraria sibirica Pall., a halophyte with strong salt tolerance. The physicochemical properties, multiple sequence alignment, gene structure and motif analysis, and chromosomal distributions were analyzed, and phylogenetic analysis, cis-regulatory elements analysis, and gene transcription and expression analysis of Ns14-3-3s were conducted. The results revealed that the Ns14-3-3 gene family consists of nine members, which are divided into two groups: ε (four members) and non-ε (five members). These members are acidic hydrophilic proteins. The genes are distributed randomly on chromosomes, and the number of introns varies widely among the two groups. However, all genes have similar conserved domains and three-dimensional protein structures. The main differences are found at the N-terminus and C-terminus. The promoter region of Ns14-3-3s contains multiple cis-acting elements related to light, plant hormones, and abiotic stress responses. Transcriptional profiling and gene expression pattern analysis revealed that Ns14-3-3s were expressed in all tissues, although with varying patterns. Under salt stress conditions, Ns14-3-3 1a, Ns14-3-3 1b, Ns14-3-3 5a, and Ns14-3-3 7a showed significant changes in gene expression. Ns14-3-3 1a expression decreased in all tissues, Ns14-3-3 7a expression decreased by 60% to 71% in roots, and Ns14-3-3 1b expression increased by 209% to 251% in stems. The most significant change was observed in Ns14-3-3 5a, with its expression in stems increasing by 213% to 681%. The yeast two-hybrid experiments demonstrated that Ns14-3-3 5a interacts with NsVP1 (vacuolar H+-pyrophosphatase). This result indicates that Ns14-3-3 5a may respond to salt stress by promoting ionic vacuole compartmentalization in stems and leaves through interactions with NsVP1. In addition, N. sibirica has a high number of stems, allowing it to compartmentalize more ions through its stem and leaf. This may be a contributing factor to its superior salt tolerance compared to other plants.

Asunto(s)

Magnoliopsida , Estrés Salino , Filogenia , Estrés Salino/genética , Tolerancia a la Sal/genética , Intrones/genética , Proteínas 14-3-3/genética , Pirofosfatasa Inorgánica , Proteínas de Plantas/genética , Regulación de la Expresión Génica de las Plantas , Estrés Fisiológico/genética

RESUMEN

Vascular Plant One­zinc Finger (VOZ) transcription factor can respond to a variety of abiotic stresses, however its function in cotton and the molecular mechanisms of response to salt tolerance remained unclear. In this study, we found that GhVOZ1 is highly expressed in stamen and stem of cotton under normal conditions. The expression of GhVOZ1 increased significantly after 3 h of salt treatment in three-leaf staged upland cotton. Overexpressed transgenic lines of GhVOZ1 in Arabidopsis and upland cotton were treated with salt stress and we found that GhVOZ1 could respond positively to salt stress. GhVOZ1 can regulate Arabidopsis Vacuolar Proton Pump Pyrophosphatase (H+-PPase) gene (AVP1) expression through specific binding to GCGTCTAAAGTACGC site on GhAVP1 promoter, which was examined through Dual-luciferase assay and Electrophoretic mobility shift assay (EMSA). AVP1 expression was significantly increased in Arabidopsis with GhVOZ1 overexpression, while GhAVP1 expression was decreased in virus induced gene silenced (VIGS) cotton plants of GhVOZ1. Knockdown of GhAVP1 expression in cotton plants by VIGS showed decreased superoxide dismutase (SOD) and peroxidase (POD) activities, whereas an increased malondialdehyde (MDA) content and ultimately decreased salt tolerance. The GhVOZ1-AVP1 module could maintain sodium ion homeostasis through cell ion transport and positively regulate the salt tolerance in cotton, providing new ideas and insights for the study of salt tolerance.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Gossypium/genética , Tolerancia a la Sal/genética , Arabidopsis/genética , Plantas Modificadas Genéticamente/genética , Proteínas de Arabidopsis/metabolismo , Estrés Fisiológico/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Pirofosfatasa Inorgánica/genética , Pirofosfatasa Inorgánica/metabolismo

RESUMEN

Vigna radiata H+-translocating pyrophosphatases (VrH+-PPases, EC 3.6.1.1) are present in various endomembranes of plants, bacteria, archaea, and certain protozoa. They transport H+ into the lumen by hydrolyzing pyrophosphate, which is a by-product of many essential anabolic reactions. Although the crystal structure of H+-PPases has been elucidated, the H+ translocation mechanism of H+-PPases in the solution state remains unclear. In this study, we used hydrogen-deuterium exchange (HDX) coupled with mass spectrometry (MS) to investigate the dynamics of H+-PPases between the previously proposed R state (resting state, Apo form), I state (intermediate state, bound to a substrate analog), and T state (transient state, bound to inorganic phosphate). When hydrogen was replaced by proteins in deuterium oxide solution, the backbone hydrogen atoms, which were exchanged with deuterium, were identified through MS. Accordingly, we used deuterium uptake to examine the structural dynamics and conformational changes of H+-PPases in solution. In the highly conserved substrate binding and proton exit regions, HDX-MS revealed the existence of a compact conformation with deuterium exchange when H+-PPases were bound with a substrate analog and product. Thus, a novel working model was developed to elucidate the in situ catalytic mechanism of pyrophosphate hydrolysis and proton transport. In this model, a proton is released in the I state, and the TM5 inner wall serves as a proton piston.

Asunto(s)

Pirofosfatasa Inorgánica , Vigna , Pirofosfatasa Inorgánica/metabolismo , Vigna/metabolismo , Protones , Deuterio/metabolismo , Difosfatos/metabolismo , Medición de Intercambio de Deuterio , Hidrógeno/metabolismo , Espectrometría de Masas

RESUMEN

Inorganic pyrophosphate (PPi) is generated as an intermediate or byproduct of many fundamental metabolic pathways, including DNA/RNA synthesis. The intracellular concentration of PPi must be regulated as buildup can inhibit many critical cellular processes. Inorganic pyrophosphatases (PPases) hydrolyze PPi into two orthophosphates (Pi), preventing the toxic accumulation of the PPi byproduct in cells and making Pi available for use in biosynthetic pathways. Here, the crystal structure of a family I inorganic pyrophosphatase from Legionella pneumophila is reported at 2.0 Šresolution. L. pneumophila PPase (LpPPase) adopts a homohexameric assembly and shares the oligonucleotide/oligosaccharide-binding (OB) ß-barrel core fold common to many other bacterial family I PPases. LpPPase demonstrated hydrolytic activity against a general substrate, with Mg2+ being the preferred metal cofactor for catalysis. Legionnaires' disease is a severe respiratory infection caused primarily by L. pneumophila, and thus increased characterization of the L. pneumophila proteome is of interest.

Asunto(s)

Legionella pneumophila , Enfermedad de los Legionarios , Humanos , Legionella pneumophila/genética , Pirofosfatasa Inorgánica/genética , Cristalografía por Rayos X , Enfermedad de los Legionarios/genética , Enfermedad de los Legionarios/microbiología

RESUMEN

Self-incompatibility (SI) is a widespread genetically determined system in flowering plants that prevents self-fertilization to promote gene flow and limit inbreeding. S-RNase-based SI is characterized by the arrest of pollen tube growth through the pistil. Arrested pollen tubes show disrupted polarized growth and swollen tips, but the underlying molecular mechanism is largely unknown. Here, we demonstrate that the swelling at the tips of incompatible pollen tubes in pear (Pyrus bretschneideri [Pbr]) is mediated by the SI-induced acetylation of the soluble inorganic pyrophosphatase (PPA) PbrPPA5. Acetylation at Lys-42 of PbrPPA5 by the acetyltransferase GCN5-related N-acetyltransferase 1 (GNAT1) drives accumulation of PbrPPA5 in the nucleus, where it binds to the transcription factor PbrbZIP77, forming a transcriptional repression complex that inhibits the expression of the pectin methylesterase (PME) gene PbrPME44. The function of PbrPPA5 as a transcriptional repressor does not require its PPA activity. Downregulating PbrPME44 resulted in increased levels of methyl-esterified pectins in growing pollen tubes, leading to swelling at their tips. These observations suggest a mechanism for PbrPPA5-driven swelling at the tips of pollen tubes during the SI response. The targets of PbrPPA5 include genes encoding cell wall-modifying enzymes, which are essential for building a continuous sustainable mechanical structure for pollen tube growth.

Asunto(s)

Tubo Polínico , Pyrus , Ribonucleasas/metabolismo , Pirofosfatasa Inorgánica/genética , Pirofosfatasa Inorgánica/metabolismo , Acetilación , Pyrus/metabolismo

Asunto(s)

Tubo Polínico , Pyrus , Tubo Polínico/metabolismo , Pyrus/metabolismo , Pirofosfatasa Inorgánica/metabolismo , Acetilación , Polen/metabolismo

RESUMEN

Salmonella is one of the most widely distributed and harmful food-borne pathogens; thus, the rapid detection of viable Salmonella is important for ensuring food safety. In this study, a rapid visual strategy based on loop-mediated isothermal amplification (LAMP) with the addition of thermal inorganic pyrophosphatase and linked with an ammonium molybdate chromogenic buffer was established to detect Salmonella. Specific primers were designed based on the phoP gene of Salmonella spp. The pyrophosphatase concentration, LAMP time, addition of ammonium molybdate chromogenic buffer, and color reaction time were optimized. Based on the optimal conditions, the sensitivity and specificity of the method were examined. In addition, the ability to detect actual samples was verified using apple juice containing Salmonella. LAMP was performed at 65°C for 45 min in the presence of thermal inorganic pyrophosphatase at a final concentration of 4 U ml-1, and 20 µl of the LAMP product was reacted with 50 µl of phosphate chromogenic buffer at 25°C for 15 min. According to our results, the limit of detection of the LAMP assay for viable Salmonella was 1.83 × 102 CFU per reaction, and nonspecific amplification was not observed. The detection rates of Salmonella Typhimurium with different concentrations in apple juice were 89.11%-94.80%, which verifies that the visual detection strategy is suitable for actual sample detection.

Asunto(s)

Pirofosfatasa Inorgánica , Pirofosfatasas , Técnicas de Amplificación de Ácido Nucleico/métodos , Salmonella typhimurium/genética , Sensibilidad y Especificidad

RESUMEN

We report the long way to the correct diagnosis in two teenage sisters who developed a cardiac arrest after consuming minimal amounts of alcohol. The older girl dramatically survived two cardiac arrests at the age of 14 and 15 years. She underwent an extensive examination that revealed isolated cardiac abnormalities including fibrosis, dilated cardiomyopathy and inflammation. The younger girl also had a cardiac arrest at the age of 15 and died suddenly after consuming 1-2 beers, 3 years after her sister´s first incident. Autopsy of the heart revealed acute myocarditis without structural alterations. Multigene panel analysis (not including PPA2) showed SCN5A and CACNA1D variants in both sisters and their healthy mother. Six years later duo exome allowed the diagnosis of an autosomal recessive PPA2-related mitochondriopathy. We discuss the molecular results and clinical picture of our patients compared to other PPA2-related cases. We highlight the diagnostic contribution of multigene panels and exome analysis. The genetic diagnosis is important for medical care and for everyday life, specifically because alcohol intake can result in cardiac arrest and should be strictly avoided.   Conclusion: Duo exome sequencing clarified the diagnosis of PPA2-related mitochondriopathy in two sisters with isolated cardiac features and sudden cardiac arrest triggered by minimal amounts of alcohol. What is Known: • Multigene-Panel or exome analysis is a valuable tool to identify genetic causes of hereditary cardiac arrhythmias. • Variants of unknown significance can lead to misinterpretation. PPA2-related mitochondriopathy is a very rare autosomal recessive condition that is normally fatal in infancy. What is New: • Duo exome analysis in two teeenage sisters with cardiac arrest revealed a homozygous mild PPA2 mutation as the underlying pathology restricted to the heart muscle.

Asunto(s)

Cerveza , Paro Cardíaco , Femenino , Adolescente , Humanos , Paro Cardíaco/genética , Mutación , Muerte Súbita Cardíaca/etiología , Muerte Súbita Cardíaca/patología , Arritmias Cardíacas/complicaciones , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Pirofosfatasa Inorgánica/genética , Pirofosfatasa Inorgánica/metabolismo