The different concentration of specific ion species and the electrodiffusion of the ions down their electrochemical gradient generate transmembrane potential. The regulation of membrane potential for the function of numerous membrane proteins such as ion channels, transporters, pumps and enzymes plays primary role in the conversion of extracellular electric stimulation into a sequence of intracellular biochemical signals. Some ion channels regulated by membrane potential are well known, and the membrane non-ion channels protein is also modulated physiologically by membrane potential.
Humans ; Ion Channel Gating ; physiology ; Ion Channels ; metabolism ; Membrane Potentials ; physiology ; Phosphoric Monoester Hydrolases ; metabolism ; Receptors, G-Protein-Coupled ; metabolism

DNA Damage ; DNA Glycosylases ; genetics ; metabolism ; DNA Repair Enzymes ; genetics ; metabolism ; Humans ; Phosphoric Monoester Hydrolases ; genetics ; metabolism

BACKGROUNDIn our previous studies, we found the expression of 14-kD phosphohistidine phosphatase (PHPT1) was associated with lung cancer cells migration and invasion, and PHPT1 mRNA expression level in lung cancer tissues clinically correlated with lymph node metastasis. In the present study, we aimed to further investigate the expression of PHPT1 protein in lung cancer.

METHODSExpression of PHPT1 protein in tissue samples from 146 lung cancers and 30 normal tissues adjacent to lung cancers was assessed using immunohistochemical method. Fisher's exact test was used to analyze expression patterns of PHPT1 protein in these tissue types. Meanwhile, we studied the correlation between expression of PHPT1 protein and clinicopathological features in lung cancer.

RESULTSSignificantly higher expression levels of PHPT1 protein were found in lung cancer samples (53.42%) than in normal tissues adjacent to lung cancer (23.33%) (P = 0.003). Fisher's exact test showed that lung cancer stage positively correlated with expression of PHPT1 protein (P = 0.02), and lung cancer samples with lymph node metastasis showed higher PHPT1 protein expression (P = 0.016) than the samples without lymph node metastasis.

CONCLUSIONSThe results of this study agree with findings from our previous study of PHPT1 mRNA expression in lung cancer tissues, and strongly suggest that PHPT1 protein is closely associated with the carcinogenesis and metastasis of lung cancer. Thus, therapy targeting PHPT1 (inhibition or silencing) could be potentially benefited for lung cancer patients.

Blotting, Western ; Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; In Vitro Techniques ; Lung Neoplasms ; metabolism ; Phosphoric Monoester Hydrolases ; metabolism

Compartments of soil microorganism and enzymes between stereoscopic cultivation (three storeys) and field cultivation (CK) of Panax notoginseng were carried out, and the effects on P. notoginseng agronomic characters were also studied. Results show that concentration of soil microorganism of stereoscopic cultivation was lower than field cultivation; the activity of soil urea enzyme, saccharase and neutral phosphatase increased from lower storey to upper storey; the activity of soil urea enzyme and saccharase of lower and upper storeys were significantly lower than CK; agronomic characters of stereoscopic cultivated P. notoginsengin were inferior to field cultivation, the middle storey with the best agronomic characters among the three storeys. The correlation analysis showed that fungi, actinomycetes and neutral phosphatase were significantly correlated with P. notoginseng agronomic characters; concentration of soil fungi and bacteria were significantly correlated with the soil relative water content; actinomycete and neutral phosphatase were significantly correlated with soil pH and relative water content, respectively; the activities of soil urea enzyme and saccharase were significantly correlated with the soil daily maximum temperature difference. Inconclusion, The current research shows that the imbalance of soil microorganism and the acutely changing of soil enzyme activity were the main reasons that caused the agronomic characters of stereoscopic cultivated P. notoginseng were worse than field cultivation. Thus improves the concentration of soil microorganism and enzyme activity near to field soil by improving the structure of stereoscopic cultivation is very important. And it was the direction which we are endeavoring that built better soil ecological environment for P. notoginseng of stereoscopic cultivation.
Hydrogen-Ion Concentration ; Panax notoginseng ; growth & development ; Phosphoric Monoester Hydrolases ; metabolism ; Soil ; chemistry ; Soil Microbiology ; beta-Fructofuranosidase ; metabolism

OBJECTIVETo investigate the effect of SHIP gene mutation on the cell cycle and its related gene expression in K562 cells.

METHODSThe recombined green fluorescent protein (GFP) containing FIV-SHIP gene was transfected into K562 cells. The transfection efficiency and cell cycle of K562/SHIP were assessed by flow cytometry (FCM). The proliferation of K562 cells was detected by MTT assay, the mRNA levels of SHIP by real-time fluorescent relative-quantification reverse transcriptional PCR (FQ-PCR), and the protein levels of SHIP, Cyclin D1, p21(WAF1/CIPI) and p27(KIP1) by Western blot.

RESULTSWild type SHIP inhibited K562 cell proliferation and caused a G(0)/G(1) arrest \[(34.2 +/- 7.8)% vs (0.7 +/- 8.3)% (P < 0.01)\]; while the point mutation of SHIP gene did not show such effect. Western blot results showed that the Akt phosphorylation and cyclin D1 expression was significantly decreased (P < 0.01), and the expression of p27(KIP1) and p21(WAF1/CIPI) increased. Site-directed mutation of SHIP gene SH2 domain (TTC-->CTC, Phe-->Leu) did not influence the Akt phosphorylation and cyclins (P > 0.05).

CONCLUSION(1) wtSHIP gene can down-regulate Akt phosphorylation and result in inhibition of cyclin D1 expression, up-regulating p27(KIP1) and p21(WAF1/CIPI) expression, finally leading to the reduction of K562 cell proliferation, and inducing G(0)/G(1) phase arrest. (2) SHIP gene suppresses the proliferation of K562, being dependent on its intact structure and function.

Cell Cycle Proteins ; metabolism ; Humans ; Inositol Polyphosphate 5-Phosphatases ; K562 Cells ; Mutation ; Phosphoric Monoester Hydrolases ; genetics ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Transfection

OBJECTIVETo investigate the effect and mechanisms of tumor suppressor gene PTEN on the induction of anoikis of hepatocellular carcinoma SMMC-7721 cells.

METHODSSMMC-7721 cells were transfected with GFP plasmids containing wild-type PTEN or phosphatase inactivating mutant PTEN (C124A-PTEN) in vitro; The PTEN expression and the phosphorylation levels of focal adhesion kinase (FAK) and protein kinase B (PKB/Akt) were detected by Western blotting; Flow cytometry assay and laser scanning confocal microscopy were used to analyze apoptosis in adherent and non-adherent cells.

RESULTSCompared with the control, PTEN expression in the cells transfected with wild-type PTEN increased to 248%, while the phosphorylation level of FAK and Akt decreased 65.2% and 89.1%, respectively; and the anoikis percentage increased from 9.5% to 31.3%. In the cells transfected with C124A-PTEN, neither the phosphorylation of FAK and Akt nor the anoikis percentage had obviously changed, although the PTEN expression enhanced dramatically in comparison with the control.

CONCLUSIONThrough its phosphatase activity, tumor suppressor gene PTEN can suppress the phosphorylation of FAK and Akt, and induce anoikis in hepatocellular carcinoma cells.

Anoikis ; physiology ; Carcinoma, Hepatocellular ; pathology ; Focal Adhesion Protein-Tyrosine Kinases ; metabolism ; Humans ; Liver Neoplasms ; pathology ; PTEN Phosphohydrolase ; biosynthesis ; genetics ; Phosphoric Monoester Hydrolases ; metabolism ; Phosphorylation ; Tumor Cells, Cultured

Based on the principle of the pathway engineering, a novel pathway of producing glycerol was built in E. coli. The gpd1 gene encoding glycerol 3-phosphate dehydrogenase and the hor2 gene encoding glycerol 3-phosphatase were cloned from Saccharomyces cerevisiae, respectively. The two genes were inserted into expression vector pSE380 together. A recombinant plasmid pSE-gpd1-hor2 containing polycistron was constructed under the control of the strong trc promoter. Then it was transformed into E. coli BL21. The result showed the recombinant microorganism GxB-gh could convert glucose to glycerol directly. And the recombinant microorganism GxB-gh was incubated to produce glycerol from D-glucose in the fermentor. The maximal concentration of glycerol was 46.67g/L at 26h. Conversion rate of glucose was 42.87%. The study is about "green" producing glycerol by recombinant microorganism and is also useful for further working in recombining microorganism of producing 1,3-propanediol.
Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Fermentation ; Fungal Proteins ; biosynthesis ; genetics ; Genetic Engineering ; Glycerol ; metabolism ; Glycerolphosphate Dehydrogenase ; biosynthesis ; genetics ; Phosphoric Monoester Hydrolases ; biosynthesis ; genetics ; Saccharomyces cerevisiae ; enzymology ; genetics

Glucose homeostasis is tightly controlled by the regulation of glucose production in the liver and glucose uptake into peripheral tissues, such as skeletal muscle and adipose tissue. Under prolonged fasting, hepatic gluconeogenesis is mainly responsible for glucose production in the liver, which is essential for tissues, organs, and cells, such as skeletal muscle, the brain, and red blood cells. Hepatic gluconeogenesis is controlled in part by the concerted actions of transcriptional regulators. Fasting signals are relayed by various intracellular enzymes, such as kinases, phosphatases, acetyltransferases, and deacetylases, which affect the transcriptional activity of transcription factors and transcriptional coactivators for gluconeogenic genes. Protein arginine methyltransferases (PRMTs) were recently added to the list of enzymes that are critical for regulating transcription in hepatic gluconeogenesis. In this review, we briefly discuss general aspects of PRMTs in the control of transcription. More specifically, we summarize the roles of four PRMTs: PRMT1, PRMT 4, PRMT 5, and PRMT 6, in the control of hepatic gluconeogenesis through specific regulation of FoxO1- and CREB-dependent transcriptional events.
Acetyltransferases ; Adipose Tissue ; Arginine* ; Brain ; Erythrocytes ; Fasting ; Gluconeogenesis ; Glucose* ; Homeostasis ; Liver ; Metabolism* ; Methyltransferases* ; Muscle, Skeletal ; Phosphoric Monoester Hydrolases ; Phosphotransferases ; Protein-Arginine N-Methyltransferases ; Transcription Factors

OBJECTIVETo screen obesity-related protein biomarkers of young men using differential proteomic method and OffGel electrophoresis.

METHODSTen male obese volunteers with the age of 18 - 44 years were selected. The control group was matched with the ratio of 1:1 considering the factors of age and gender etc. Two milliliter venous blood was collected after 8 hours fasting. Albumin and IgG were removed from the plasma samples with highly specific immune-affinity method. Then the peptide-mixed samples were separated by pI with OffGel electrophoresis after solution digestion. Further separation and identification were performed by Nano HPLC-Chip-MS/MS system. The different proteins between the two groups were compared.

RESULTSOverall, 332 and 301 proteins were identified in the obesity and control groups, respectively. There were 43 proteins with significant differences between the two groups, 17 of which were in the control group and 26 in the obesity group. Protein function annotation results showed that the level of adiponectin was lower while the level of C-reaction protein and three other phosphatases were higher in the obesity group compared with the control group.

CONCLUSIONAdiponectin, C-reaction protein and three phosphatases were closely related to obesity of young men.

Adiponectin ; blood ; Adolescent ; Adult ; Biomarkers ; blood ; C-Reactive Protein ; metabolism ; China ; epidemiology ; Humans ; Male ; Obesity ; blood ; epidemiology ; Phosphoric Monoester Hydrolases ; blood ; Proteomics ; Young Adult

Methyl parathion hydrolase (MPH) is a novel member of organophosphorus hydrolase. In this study, mpd gene was expressed in Escherichia coli DH5alpha with its native promoter. MPH was purified to homogeneity. Results show that metal-chelating compounds cannot inhabit the enzyme activity. Inductively Coupled Plasma-Atomic Emission Spectrometry analysis showed that MPH is a zinc-containing enzyme, the Zinc to enzyme molar ratio is near 2:1. In order to investigate critical residues related to enzymatic activity of MPH, chemical modification reagents EDC, DEPC, butanedione and pyridoxal were tested. Experiment results suggested that aspartate, glutamate, arginine and lysine are not important for enzyme activity. But DEPC, which can modify histidine residue, inactivate the enzyme activity greatly, and the inactivation rate is 9.6 h(-1). This result reflects that histidine residues are essential for enzyme activity. All these results provide basic data for MPH structure and molecular evolution research.
Aryldialkylphosphatase ; chemistry ; Enzyme Activation ; drug effects ; Escherichia coli ; genetics ; metabolism ; Histidine ; chemistry ; Phosphoric Monoester Hydrolases ; chemistry ; Recombinant Fusion Proteins ; biosynthesis ; chemistry ; genetics