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1.
Plant Cell ; 35(9): 3544-3565, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37306489

RESUMO

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.


Assuntos
Tubo Polínico , Pyrus , Ribonucleases/metabolismo , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Acetilação , Pyrus/metabolismo
2.
FASEB J ; 38(19): e70053, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39373847

RESUMO

Liver fibrosis is characterized by a wound-healing response and may progress to liver cirrhosis and even hepatocellular carcinoma. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) is a tumor suppressor that participates in malignant diseases. However, the role of LHPP in liver fibrosis has not been determined. Herein, the function and regulatory network of LHPP were explored in liver fibrosis. The expression of LHPP in human and murine fibrotic liver tissues was assessed via immunohistochemistry and Western blot analysis. In addition, liver fibrosis was induced in wild-type (WT) and LHPP-/- (KO) mice after carbon tetrachloride (CCl4) or thioacetamide (TAA) treatment. The effect of LHPP was systematically assessed by using specimens acquired from the above murine models. The functional role of LHPP was further explored by detecting the pathway activity of TGF-ß/Smad3 and apoptosis after interfering with LHPP in vitro. To explore whether the function of LHPP depended on the TGF-ß/Smad3 pathway in vivo, an inhibitor of the TGF-ß/Smad3 pathway was used in CCl4-induced WT and KO mice. LHPP expression was downregulated in liver tissue samples from fibrosis patients and fibrotic mice. LHPP deficiency aggravated CCl4- and TAA-induced liver fibrosis. Moreover, through immunoblot analysis, we identified the TGF-ß/Smad3 pathway as a key downstream pathway of LHPP in vivo and in vitro. The effect of LHPP deficiency was reversed by inhibiting the TGF-ß/Smad3 pathway in liver fibrosis. These results revealed that LHPP deficiency exacerbates liver fibrosis through the TGF-ß/Smad3 pathway. LHPP may be a potential therapeutic target in hepatic fibrosis.


Assuntos
Pirofosfatase Inorgânica , Cirrose Hepática , Camundongos Knockout , Transdução de Sinais , Proteína Smad3 , Fator de Crescimento Transformador beta , Animais , Proteína Smad3/metabolismo , Proteína Smad3/genética , Camundongos , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Humanos , Pirofosfatase Inorgânica/metabolismo , Pirofosfatase Inorgânica/genética , Fator de Crescimento Transformador beta/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Apoptose , Tetracloreto de Carbono/toxicidade
3.
Plant J ; 115(5): 1261-1276, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37256847

RESUMO

Grain chalkiness is a major concern in rice production because it impacts milling yield and cooking quality, eventually reducing market value of the rice. A gene encoding vacuolar H+ translocating pyrophosphatase (V-PPase) is a major quantitative trait locus in indica rice, controlling grain chalkiness. Higher transcriptional activity of this gene is associated with increased chalk content. However, whether the suppression of V-PPase could reduce chalkiness is not clear. Furthermore, natural variation in the chalkiness of japonica rice has not been linked with V-PPase. Here, we describe promoter targeting of the japonica V-PPase allele that led to reduced grain chalkiness and the development of more translucent grains. Disruption of a putative GATA element by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 suppressed V-PPase activity, reduced grain chalkiness and impacted post-germination growth that could be rescued by the exogenous supply of sucrose. The mature grains of the targeted lines showed a much lower percentage of large or medium chalk. Interestingly, the targeted lines developed a significantly lower chalk under heat stress, a major inducer of grain chalk. Metabolomic analysis showed that pathways related to starch and sugar metabolism were affected in the developing grains of the targeted lines that correlated with higher inorganic pyrophosphate and starch contents and upregulation of starch biosynthesis genes. In summary, we show a biotechnology approach of reducing grain chalkiness in rice by downregulating the transcriptional activity of V-PPase that presumably leads to altered metabolic rates, including starch biosynthesis, resulting in more compact packing of starch granules and formation of translucent rice grains.


Assuntos
Oryza , Oryza/metabolismo , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Grão Comestível/genética , Grão Comestível/metabolismo , Amido/metabolismo , Mutagênese
4.
Nature ; 555(7698): 678-682, 2018 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-29562234

RESUMO

Histidine phosphorylation, the so-called hidden phosphoproteome, is a poorly characterized post-translational modification of proteins. Here we describe a role of histidine phosphorylation in tumorigenesis. Proteomic analysis of 12 tumours from an mTOR-driven hepatocellular carcinoma mouse model revealed that NME1 and NME2, the only known mammalian histidine kinases, were upregulated. Conversely, expression of the putative histidine phosphatase LHPP was downregulated specifically in the tumours. We demonstrate that LHPP is indeed a protein histidine phosphatase. Consistent with these observations, global histidine phosphorylation was significantly upregulated in the liver tumours. Sustained, hepatic expression of LHPP in the hepatocellular carcinoma mouse model reduced tumour burden and prevented the loss of liver function. Finally, in patients with hepatocellular carcinoma, low expression of LHPP correlated with increased tumour severity and reduced overall survival. Thus, LHPP is a protein histidine phosphatase and tumour suppressor, suggesting that deregulated histidine phosphorylation is oncogenic.


Assuntos
Histidina/metabolismo , Pirofosfatase Inorgânica/metabolismo , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/patologia , Proteínas Supressoras de Tumor/metabolismo , Animais , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/patologia , Modelos Animais de Doenças , Humanos , Pirofosfatase Inorgânica/deficiência , Pirofosfatase Inorgânica/genética , Masculino , Camundongos , Fosforilação , Proteômica , Análise de Sobrevida , Serina-Treonina Quinases TOR/metabolismo , Carga Tumoral , Proteínas Supressoras de Tumor/deficiência , Proteínas Supressoras de Tumor/genética
5.
PLoS Genet ; 17(8): e1009674, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34351899

RESUMO

In plants, the effective mobilization of seed nutrient reserves is crucial during germination and for seedling establishment. The Arabidopsis H+-PPase-loss-of-function fugu5 mutants exhibit a reduced number of cells in the cotyledons. This leads to enhanced post-mitotic cell expansion, also known as compensated cell enlargement (CCE). While decreased cell numbers have been ascribed to reduced gluconeogenesis from triacylglycerol, the molecular mechanisms underlying CCE remain ill-known. Given the role of indole 3-butyric acid (IBA) in cotyledon development, and because CCE in fugu5 is specifically and completely cancelled by ech2, which shows defective IBA-to-indoleacetic acid (IAA) conversion, IBA has emerged as a potential regulator of CCE. Here, to further illuminate the regulatory role of IBA in CCE, we used a series of high-order mutants that harbored a specific defect in IBA-to-IAA conversion, IBA efflux, IAA signaling, or vacuolar type H+-ATPase (V-ATPase) activity and analyzed the genetic interaction with fugu5-1. We found that while CCE in fugu5 was promoted by IBA, defects in IBA-to-IAA conversion, IAA response, or the V-ATPase activity alone cancelled CCE. Consistently, endogenous IAA in fugu5 reached a level 2.2-fold higher than the WT in 1-week-old seedlings. Finally, the above findings were validated in icl-2, mls-2, pck1-2 and ibr10 mutants, in which CCE was triggered by low sugar contents. This provides a scenario in which following seed germination, the low-sugar-state triggers IAA synthesis, leading to CCE through the activation of the V-ATPase. These findings illustrate how fine-tuning cell and organ size regulation depend on interplays between metabolism and IAA levels in plants.


Assuntos
Arabidopsis/fisiologia , Ácidos Indolacéticos/metabolismo , Indóis/farmacologia , Pirofosfatase Inorgânica/genética , ATPases Vacuolares Próton-Translocadoras/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Crescimento Celular/efeitos dos fármacos , Cotilédone/efeitos dos fármacos , Cotilédone/genética , Cotilédone/fisiologia , Enoil-CoA Hidratase/genética , Germinação , Mutação com Perda de Função , Tamanho do Órgão , Transdução de Sinais/efeitos dos fármacos , Açúcares/metabolismo
6.
Parasitol Res ; 123(10): 353, 2024 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-39419910

RESUMO

Integral membrane pyrophosphatases (mPPases) hydrolyze pyrophosphate. This enzymatic mechanism is coupled with the pumping of H + and/or Na + across membranes, which can be either K + -dependent or K + -independent. Inorganic proton-translocating pyrophosphatases (H + -PPases) can transport protons across cell membranes and are reported in various organisms such as plants, bacteria, and protozoan parasites. The evolutionary implications of these enzymes are of great interest for proposing approaches related to the treatment of parasitic of phytopathogenic diseases. This work presents a literature review on pyrophosphate, pyrophosphatases, their inhibitors and emphasizes H + -PPases found in various medically significant protozoan parasites such as Toxoplasma gondii, the causative agent of toxoplasmosis, and Plasmodium falciparum, the causative agent of malaria, as well as protozoan species that primarily affect animals, such as Eimeria maxima and Besnoitia besnoiti.


Assuntos
Eucariotos , Animais , Eucariotos/enzimologia , Eucariotos/genética , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Difosfatos/metabolismo
7.
Int J Mol Sci ; 25(11)2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38891956

RESUMO

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.


Assuntos
Cistationina beta-Sintase , Cistationina beta-Sintase/metabolismo , Cistationina beta-Sintase/química , Cistationina beta-Sintase/genética , Mutação , Ligação Proteica , Mutagênese Sítio-Dirigida , Nucleotídeos de Adenina/metabolismo , Nucleotídeos de Adenina/química , Domínios Proteicos , Pirofosfatases/metabolismo , Pirofosfatases/química , Pirofosfatases/genética , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Pirofosfatase Inorgânica/metabolismo , Pirofosfatase Inorgânica/química , Pirofosfatase Inorgânica/genética , Modelos Moleculares , Sítios de Ligação
8.
Eur J Pediatr ; 182(8): 3785-3788, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37269378

RESUMO

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.


Assuntos
Cerveja , Parada Cardíaca , Feminino , Adolescente , Humanos , Parada Cardíaca/genética , Mutação , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/patologia , Arritmias Cardíacas/complicações , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo
9.
Am J Forensic Med Pathol ; 44(4): 332-335, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37249496

RESUMO

ABSTRACT: The PPA2 gene encodes a mitochondrial pyrophosphatase protein. Mutations in the gene are inherited in an autosomal recessive fashion and, when mutated, function to induce mitochondrial ATP production failure resulting in increased stress on the heart and sudden cardiac death, especially when combined with alcohol. Herein, we describe a case of a 19-year-old female patient with a history of "alcohol intolerance" who was found unexpectedly deceased after consuming a minimal amount of alcohol. Histological examination of her heart revealed widespread fibrosis of the left ventricle and the interventricular septum. Other findings include hypertrophied myocytes, including some with pleomorphic nuclei. Genetic studies were performed on postmortem blood, revealing heterozygous PPA2 gene mutations, the pathogenic variant c.683C>T (p.Pro228Leu), and the other variant c.814C>T (p.His272Tyr), a novel variant of undetermined significance. We propose that the variant of undetermined significance is likely a pathogenic mutation due to the decedent's phenotype.


Assuntos
Morte Súbita Cardíaca , Etanol , Feminino , Humanos , Adolescente , Adulto Jovem , Adulto , Mutação , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Fibrose , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo
10.
Biochem Cell Biol ; 100(5): 425-436, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35926232

RESUMO

Inorganic pyrophosphatase (iPPase) is an enzyme that cleaves pyrophosphate into two phosphate molecules. This enzyme is an essential component of in vitro transcription (IVT) reactions for RNA preparation as it prevents pyrophosphate from precipitating with magnesium, ultimately increasing the rate of the IVT reaction. Large-scale RNA production is often required for biochemical and biophysical characterization studies of RNA, therefore requiring large amounts of IVT reagents. Commercially purchased iPPase is often the most expensive component of any IVT reaction. In this paper, we demonstrate that iPPase can be produced in large quantities and high quality using a reasonably generic laboratory facility and that laboratory-purified iPPase is as effective as commercially available iPPase. Furthermore, using size exclusion chromatography coupled with multi-angle light scattering and dynamic light scattering, analytical ultracentrifugation, and small-angle X-ray scattering, we demonstrate that yeast iPPase can form tetramers and hexamers in solution as well as the enzymatically active dimer. Our work provides a robust protocol for laboratories involved with RNA in vitro transcription to efficiently produce active iPPase, significantly reducing the financial strain of large-scale RNA production.


Assuntos
Difosfatos , Pirofosfatase Inorgânica , Pirofosfatase Inorgânica/química , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Magnésio , Pirofosfatases/química , Pirofosfatases/genética , RNA
11.
Nat Chem Biol ; 16(10): 1120-1128, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32690945

RESUMO

The NUDIX hydrolase NUDT15 was originally implicated in sanitizing oxidized nucleotides, but was later shown to hydrolyze the active thiopurine metabolites, 6-thio-(d)GTP, thereby dictating the clinical response of this standard-of-care treatment for leukemia and inflammatory diseases. Nonetheless, its physiological roles remain elusive. Here, we sought to develop small-molecule NUDT15 inhibitors to elucidate its biological functions and potentially to improve NUDT15-dependent chemotherapeutics. Lead compound TH1760 demonstrated low-nanomolar biochemical potency through direct and specific binding into the NUDT15 catalytic pocket and engaged cellular NUDT15 in the low-micromolar range. We also employed thiopurine potentiation as a proxy functional readout and demonstrated that TH1760 sensitized cells to 6-thioguanine through enhanced accumulation of 6-thio-(d)GTP in nucleic acids. A biochemically validated, inactive structural analog, TH7285, confirmed that increased thiopurine toxicity takes place via direct NUDT15 inhibition. In conclusion, TH1760 represents the first chemical probe for interrogating NUDT15 biology and potential therapeutic avenues.


Assuntos
Pirofosfatases/antagonistas & inibidores , Pirofosfatases/metabolismo , Sítios de Ligação , Linhagem Celular , Desenho de Fármacos , Desenvolvimento de Medicamentos , Escherichia coli , Humanos , Pirofosfatase Inorgânica/antagonistas & inibidores , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Pirofosfatases/química , Pirofosfatases/genética , Relação Estrutura-Atividade
12.
Int J Mol Sci ; 23(21)2022 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-36361526

RESUMO

Pyrophosphate (PPi) is a byproduct of over 120 biosynthetic reactions, and an overabundance of PPi can inhibit industrial synthesis. Pyrophosphatases (PPases) can effectively hydrolyze pyrophosphate to remove the inhibitory effect of pyrophosphate. In the present work, a thermophilic alkaline inorganic pyrophosphatase from Thermococcus onnurineus NA1 was studied. The optimum pH and temperature of Ton1914 were 9.0 and 80 °C, respectively, and the half-life was 52 h at 70 °C and 2.5 h at 90 °C. Ton1914 showed excellent thermal stability, and its relative enzyme activity, when incubated in Tris-HCl 9.0 containing 1.6 mM Mg2+ at 90 °C for 5 h, was still 100%, which was much higher than the control, whose relative activity was only 37%. Real-time quantitative PCR (qPCR) results showed that the promotion of Ton1914 on long-chain DNA was more efficient than that on short-chain DNA when the same concentration of templates was supplemented. The yield of long-chain products was increased by 32-41%, while that of short-chain DNA was only improved by 9.5-15%. Ton1914 also increased the yields of UDP-glucose and UDP-galactose enzymatic synthesis from 40.1% to 84.8% and 20.9% to 35.4%, respectively. These findings suggested that Ton1914 has considerable potential for industrial applications.


Assuntos
Proteínas Arqueais , Thermococcus , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Difosfatos/farmacologia , Proteínas Arqueais/metabolismo , Pirofosfatases/genética , Pirofosfatases/metabolismo , Difosfato de Uridina
13.
Int J Mol Sci ; 23(16)2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-36012762

RESUMO

Membrane pyrophosphatases (mPPases) found in plant vacuoles and some prokaryotes and protists are ancient cation pumps that couple pyrophosphate hydrolysis with the H+ and/or Na+ transport out of the cytoplasm. Because this function is reversible, mPPases play a role in maintaining the level of cytoplasmic pyrophosphate, a known regulator of numerous metabolic reactions. mPPases arouse interest because they are among the simplest membrane transporters and have no homologs among known ion pumps. Detailed phylogenetic studies have revealed various subtypes of mPPases and suggested their roles in the evolution of the "sodium" and "proton" bioenergetics. This treatise focuses on the mechanistic aspects of the transport reaction, namely, the coupling step, the role of the chemically produced proton, subunit cooperation, and the relationship between the proton and sodium ion transport. The available data identify H+-PPases as the first non-oxidoreductase pump with a "direct-coupling" mechanism, i.e., the transported proton is produced in the coupled chemical reaction. They also support a "billiard" hypothesis, which unifies the H+ and Na+ transport mechanisms in mPPase and, probably, other transporters.


Assuntos
Difosfatos , Pirofosfatases , Difosfatos/metabolismo , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Filogenia , Probabilidade , Prótons , Pirofosfatases/metabolismo , Sódio/metabolismo
14.
Proteins ; 89(7): 853-865, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33583053

RESUMO

Inorganic pyrophosphatases (PPases) catalyze the hydrolysis of pyrophosphate to phosphates. PPases play essential roles in growth and development, and are found in all kingdoms of life. Human possess two PPases, PPA1 and PPA2. PPA1 is present in all tissues, acting largely as a housekeeping enzyme. Besides pyrophosphate hydrolysis, PPA1 can also directly dephosphorylate phosphorylated c-Jun N-terminal kinases 1 (JNK1). Upregulated expression of PPA1 has been linked to many human malignant tumors. PPA1 knockdown induces apoptosis and decreases proliferation. PPA1 is emerging as a potential prognostic biomarker and target for anti-cancer drug development. In spite of the biological and physiopathological importance of PPA1, there is no detailed study on the structure and catalytic mechanisms of mammalian origin PPases. Here we report the crystal structure of human PPA1 at a resolution of 2.4 Å. We also carried out modeling studies of PPA1 in complex with JNK1 derived phosphor-peptides. The monomeric protein fold of PPA1 is similar to those found in other family I PPases. PPA1 forms a dimeric structure that should be conserved in animal and fungal PPases. Analysis of the PPA1 structure and comparison with available structures of PPases from lower organisms suggest that PPA1 has a largely pre-organized and relatively rigid active site for pyrophosphate hydrolysis. Results from the modeling study indicate the active site of PPA1 has the potential to accommodate double-phosphorylated peptides from JNK1. In short, results from the study provides new insights into the mechanisms of human PPA1 and basis for structure-based anti-cancer drug developments using PPA1 as the target.


Assuntos
Difosfatos/química , Pirofosfatase Inorgânica/química , Proteínas Mitocondriais/química , Proteína Quinase 8 Ativada por Mitógeno/química , Fosfatos/química , Sequência de Aminoácidos , Domínio Catalítico , Clonagem Molecular , Cristalografia por Raios X , Difosfatos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Proteína Quinase 8 Ativada por Mitógeno/genética , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Modelos Moleculares , Fosfatos/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
15.
Biochem Biophys Res Commun ; 585: 8-14, 2021 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-34781059

RESUMO

Inorganic pyrophosphatase catalyzes the conversion of pyrophosphate to phosphate and is often critical for driving reactions forward in cellular processes such as nucleic acid and protein synthesis. Commonly used methods for quantifying pyrophosphatase enzyme activity employ reacting liberated phosphate with a second molecule to produce absorbance changes or employing a second enzyme in coupled reactions to produce a product with a detectable absorbance. In this investigation, a novel [31P]-NMR spectroscopy-based assay was used to quantitatively measure the formation of phosphate and evaluate the activity of inorganic pyrophosphatase from the thermoacidophilic Crenarchaeota Sulfolobus islandicus. The enzymatic activity was directly measured via integration of the [31P] resonance associated with the phosphate product (δ = 2.1 ppm). Sulfolobus islandicus inorganic pyrophosphatase preferentially utilized Mg2+ as divalent cation and had pH and temperature optimums of 6.0 of 50 °C, respectively. The Vmax value was 850 µmol/min/mg and the Km for pyrophosphate was 1.02 mM. Sequence analysis indicates the enzyme is a Family I pyrophosphatase. Sulfolobus islandicus inorganic pyrophosphatase was shown to be inhibited by sodium fluoride with a IC50 of 2.26 mM, compared to a IC50 of 0.066 mM for yeast inorganic pyrophosphatase. These studies reveal that a [31P]-NMR spectroscopy-based assay is an effective method for analyzing catalysis by phosphate-producing enzymes.


Assuntos
Proteínas Arqueais/metabolismo , Ensaios Enzimáticos/métodos , Pirofosfatase Inorgânica/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Sulfolobus/enzimologia , Sequência de Aminoácidos , Proteínas Arqueais/genética , Biocatálise , Difosfatos/metabolismo , Concentração de Íons de Hidrogênio , Pirofosfatase Inorgânica/genética , Cinética , Isótopos de Fósforo , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Sulfolobus/genética , Temperatura
16.
Genet Med ; 23(12): 2415-2425, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34400813

RESUMO

PURPOSE: Biallelic hypomorphic variants in PPA2, encoding the mitochondrial inorganic pyrophosphatase 2 protein, have been recently identified in individuals presenting with sudden cardiac death, occasionally triggered by alcohol intake or a viral infection. Here we report 20 new families harboring PPA2 variants. METHODS: Synthesis of clinical and molecular data concerning 34 individuals harboring five previously reported PPA2 variants and 12 novel variants, 11 of which were functionally characterized. RESULTS: Among the 34 individuals, only 6 remain alive. Twenty-three died before the age of 2 years while five died between 14 and 16 years. Within these 28 cases, 15 died of sudden cardiac arrest and 13 of acute heart failure. One case was diagnosed prenatally with cardiomyopathy. Four teenagers drank alcohol before sudden cardiac arrest. Progressive neurological signs were observed in 2/6 surviving individuals. For 11 variants, recombinant PPA2 enzyme activities were significantly decreased and sensitive to temperature, compared to wild-type PPA2 enzyme activity. CONCLUSION: We expand the clinical and mutational spectrum associated with PPA2 dysfunction. Heart failure and sudden cardiac arrest occur at various ages with inter- and intrafamilial phenotypic variability, and presentation can include progressive neurological disease. Alcohol intake can trigger cardiac arrest and should be strictly avoided.


Assuntos
Cardiomiopatias , Morte Súbita Cardíaca , Adolescente , Alelos , Cardiomiopatias/genética , Pré-Escolar , Morte Súbita Cardíaca/etiologia , Humanos , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Proteínas Mitocondriais/genética , Mutação
17.
Plant Physiol ; 183(2): 750-764, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32241879

RESUMO

Excessive application of nitrate, an essential macronutrient and a signal regulating diverse physiological processes, decreases malate accumulation in apple (Malus domestica) fruit, but the underlying mechanism remains poorly understood. Here, we show that an apple BTB/TAZ protein, MdBT2, is involved in regulating malate accumulation and vacuolar pH in response to nitrate. In vitro and in vivo assays indicate that MdBT2 interacts directly with and ubiquitinates a bHLH transcription factor, MdCIbHLH1, via the ubiquitin/26S proteasome pathway in response to nitrate. This ubiquitination results in the degradation of MdCIbHLH1 protein and reduces the transcription of MdCIbHLH1-targeted genes involved in malate accumulation and vacuolar acidification, including MdVHA-A, which encodes a vacuolar H+-ATPase, and MdVHP1, which encodes a vacuolar H+-pyrophosphatase, as well as MdALMT9, which encodes an aluminum-activated malate transporter. A series of transgenic analyses in apple materials including fruits, plantlets, and calli demonstrate that MdBT2 controls nitrate-mediated malate accumulation and vacuolar pH at least partially, if not completely, via regulating the MdCIbHLH1 protein level. Taken together, these findings reveal that MdBT2 regulates the stability of MdCIbHLH1 via ubiquitination in response to nitrate, which in succession transcriptionally reduces the expression of malate-associated genes, thereby controlling malate accumulation and vacuolar acidification in apples under high nitrate supply.


Assuntos
Malatos/metabolismo , Nitratos/farmacologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , Ubiquitinação/efeitos dos fármacos , Ubiquitinação/genética , ATPases Vacuolares Próton-Translocadoras/metabolismo
18.
Vet Res ; 52(1): 6, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33413587

RESUMO

Inorganic pyrophosphatase (PPase) participates in energy cycle and plays a vital role in hydrolysis of inorganic pyrophosphate (PPi) into inorganic phosphate (Pi). The aim of this study was to investigate the biological properties of a Trichinella spiralis PPase (TsPPase) and its role in larval molting and developmental process. The predicted TsPPase consisted of 367 amino acids with a molecular mass of 41.48 kDa and a pI of 5.76. Amino acid sequence alignment and phylogenetic analysis showed that the TsPPase gene encodes a functional family I soluble PPase with the same characteristics as prokaryotic, plant and animal/fungal soluble PPase. The rTsPPase was expressed and purified, it has the activity to catalyze the hydrolysis of PPi to Pi, and the activity was dependent on Mg2+, pH and temperature. The enzymatic activity of rTsPPase was significantly inhibited after its metal binding sites mutation. TsPPase was transcribed and expressed in all T. spiralis phases, especially in muscle larvae (ML) and intestinal infective larvae (IIL). Immunofluorescence assay (IFA) revealed that TsPPase was mainly located in cuticle and stichosome. When the ML and IIL were treated with TsPPase-specific siRNA-279, TsPPase expression and enzymatic activity were obviously reduced, the larval molting and development were also impeded. Intestinal IIL as well as AW burden, IIL molting rates from mice infected with siRNA-treated ML were obviously suppressed. The results indicated that rTsPPase possesses the enzymatic activity of native inorganic pyrophosphatase, and TsPPase plays an important role in development and molting process of intestinal T. spiralis larval stages.


Assuntos
Pirofosfatase Inorgânica/fisiologia , Trichinella spiralis/crescimento & desenvolvimento , Animais , Western Blotting , Eletroforese em Gel de Poliacrilamida , Feminino , Imunofluorescência , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Larva , Camundongos , Camundongos Endogâmicos BALB C , Muda/fisiologia , Mutagênese Sítio-Dirigida , Filogenia , Reação em Cadeia da Polimerase em Tempo Real , Alinhamento de Sequência , Trichinella spiralis/enzimologia , Trichinella spiralis/genética , Trichinella spiralis/fisiologia , Triquinelose/parasitologia , Triquinelose/veterinária
19.
Nature ; 523(7562): 588-91, 2015 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-26176920

RESUMO

Major depressive disorder (MDD), one of the most frequently encountered forms of mental illness and a leading cause of disability worldwide, poses a major challenge to genetic analysis. To date, no robustly replicated genetic loci have been identified, despite analysis of more than 9,000 cases. Here, using low-coverage whole-genome sequencing of 5,303 Chinese women with recurrent MDD selected to reduce phenotypic heterogeneity, and 5,337 controls screened to exclude MDD, we identified, and subsequently replicated in an independent sample, two loci contributing to risk of MDD on chromosome 10: one near the SIRT1 gene (P = 2.53 × 10(-10)), the other in an intron of the LHPP gene (P = 6.45 × 10(-12)). Analysis of 4,509 cases with a severe subtype of MDD, melancholia, yielded an increased genetic signal at the SIRT1 locus. We attribute our success to the recruitment of relatively homogeneous cases with severe illness.


Assuntos
Transtorno Depressivo Maior/genética , Loci Gênicos/genética , Estudo de Associação Genômica Ampla , Adolescente , Adulto , Povo Asiático/genética , China , Cromossomos Humanos Par 10/genética , Estudos de Coortes , Transtorno Depressivo/genética , Feminino , Genoma Humano/genética , Humanos , Pirofosfatase Inorgânica/genética , Íntrons/genética , Pessoa de Meia-Idade , Análise de Sequência de DNA , Sirtuína 1/genética , Adulto Jovem
20.
J Clin Lab Anal ; 35(12): e24077, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34699621

RESUMO

BACKGROUND: Renal cell carcinoma (RCC) is one of the highly malignant tumors in the world. Global Cancer Statistics 2020 estimated that there were 179,368 deaths from kidney tumors. Therefore, exploring the prognostic biomarkers of RCC is of great significance for RCC patients. This study aims to explore the potential mechanism and prognostic value of phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) gene-targeting co-expression microRNAs in RCC patients. METHODS: A total of 60 RCC patients were included. Quantitative real-time PCR (qRT-PCR), western blotting, and immunohistochemistry were used for LHPP, microRNA-765, microRNA-21, and microRNA-144 levels evaluation. Cell Counting Kit-8 assay, dual-luciferase reporter gene assay, invasion assay, and RNA fluorescence in situ hybridization were used for functional analyses. RESULTS: Compared with adjacent tissues, LHPP levels in cancer tissues were significantly increased (p < .001). Herein, we confirmed that microRNA-765, microRNA-21, and microRNA-144 were direct biological targets of LHPP. MicroRNA-765 (r = -0.570, p < 0.001), microRNA-21 (r = -0.495, p < .001), and microRNA-144 (r = -0.463, p < .001) expression levels were negatively correlated with LHPP expression levels. The high expression levels of microRNA-765, microRNA-21, and microRNA-144 in RCC tissues were associated with poor differentiation, recurrence, and poor prognosis (p < .05). In vitro, microRNA-765, microRNA-21, and microRNA-144 act as oncogenes to promote proliferation, invasion, and epithelial-mesenchymal transition (EMT) through targeting LHPP. CONCLUSIONS: MicroRNA-765, microRNA-21, and microRNA-144 are independent risk biomarkers for RCC patients. Inhibiting the expression levels of microRNA-765, microRNA-21, and microRNA-144 can reduce the proliferation, EMT, and invasion of RCC cells. Therefore, the above three microRNAs are expected to become molecular biomarkers for RCC therapy.


Assuntos
Carcinoma de Células Renais/patologia , Neoplasias Renais/patologia , MicroRNAs/genética , Idoso , Biomarcadores Tumorais/genética , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/mortalidade , Linhagem Celular Tumoral , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Neoplasias Renais/genética , Neoplasias Renais/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Análise de Sobrevida
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