Cytochrome P450 3A4 (CYP3A4), is the dominant human liver hemoprotein enzyme localized in the endoplasmic reticulum (ER), and is responsible for the metabolism of more than 50% of clinically relevant drugs. While we were studying CYP3A4 expression and activity in human liver, we found that anti-CYP3A4 antibody cross-reacted with a lower band in liver cytoplasmic fraction. We assessed the activities of CYP3A4 and its truncated form in the microsomal and cytoplasmic fraction, respectively. In the cytoplasmic fraction, truncated CYP3A4 showed catalytic activity when reconstituted with NADPH-cytochrome P-450 reductase and cytochrome b5. In order to determine which site was deleted in the truncated form in vitro, we transfected cells with N-terminal tagged or C-terminal tagged human CYP3A4 cDNA. The truncated CYP3A4 is the N-terminal deleted form and was present in the soluble cytoplasmic fraction. Our result shows, for the first time, that N-terminal truncated, catalytically active CYP3A4 is present principally in the cytoplasm of human liver cells.
Blotting, Western ; Catalysis ; Cell Line ; Cytochrome P-450 CYP3A/chemistry/*metabolism ; Cytoplasm/*enzymology ; Humans ; Microsomes, Liver/*enzymology

Cytoplasmic Cu/Zn superoxide dismutase (SOD1) is an antioxidant enzyme that converts superoxide to hydrogen peroxide in cells. Its spatial distribution matches that of superoxide production, allowing it to protect cells from oxidative stress. SOD1 deficiencies result in embryonic lethality and a wide range of pathologies in mice, but little is known about normal SOD1 protein expression in developing embryos. In this study, the expression pattern of SOD1 was investigated in post-implantation mouse embryos and extraembryonic tissues, including placenta, using Western blotting and immunohistochemical analyses. SOD1 was detected in embryos and extraembryonic tissues from embryonic day (ED) 8.5 to 18.5. The signal in embryos was observed at the lowest level on ED 9.5-11.5, and the highest level on ED 17.5-18.5, while levels remained constant in the surrounding extraembryonic tissues during all developmental stages examined. Immunohistochemical analysis of SOD1 expression on ED 13.5-18.5 revealed its ubiquitous distribution throughout developing organs. In particular, high levels of SOD1 expression were observed in the ependymal epithelium of the choroid plexus, ganglia, sensory cells of the olfactory and vestibulocochlear epithelia, blood cells and vessels, hepatocytes and hematopoietic cells of the liver, lymph nodes, osteogenic tissues, and skin. Thus, SOD1 is highly expressed at late stages of embryonic development in a cell- and tissue-specific manner, and can function as an important antioxidant enzyme during organogenesis in mouse embryos.
Animals ; Cerebral Cortex/embryology/enzymology ; Copulation ; Cytoplasm/*enzymology ; Embryonic Development/*physiology ; Female ; Immunohistochemistry ; Lung/embryology/enzymology ; Male ; Mice ; Mice, Inbred ICR ; Organogenesis/*physiology ; Pregnancy ; Stomach/embryology/enzymology ; Superoxide Dismutase/deficiency/genetics/*metabolism

OBJECTIVETo study the expression of enoyl CoA hydratase 1 (ECH1) and the effect when down-regulation of ECH1 gene expression in mouse hepatocarcinoma cell.

METHODSImmunofluorescence was used for detecting the expression of ECH1, and stably transfected Hca-F cells with pGPU6/GFP/Neo-shRNA-ECH1 expression plasmids. Cell proliferation was assessed by Cell counting kit-8 (CCK8) assay. The Boyden-transwell assay (8 µm pore size) was performed to analyze the inhibitory effect of shRNA on Hca-F cell migration and invasion.

RESULTSECH1 expression was obtained in the cytoplasm and upregulated expression in Hca-F cells than that in Hca-P cells. The down-regulation of ECH1 could inhibit the cell proliferation of Hca-F cells, decrease the number of cell pass through Transwell (27.07 ± 17.49) compared with scramble-negative (72.38 ± 18.83) and Hca-F controls (59.06 ± 30.33), decrease the migration capacities of Hca-F cells, increase the ratio of Hca-F cells in S phase (86.1%) compared with scramble-negative (75.8%) and Hca-F controls (66.2%) and decrease the ratio of G(1) phase (9.4%) compared with scramble-negative (24.2%) and Hca-F controls (30.3%).

CONCLUSIONECH1 serves as a potential critical factor attributes to tumor lymphatic metastasis.

Animals ; Cell Cycle ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Cytoplasm ; enzymology ; Down-Regulation ; Enoyl-CoA Hydratase ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Liver Neoplasms, Experimental ; enzymology ; pathology ; Lymphatic Metastasis ; Mice ; Plasmids ; RNA, Small Interfering ; genetics ; Transfection

OBJECTIVETo explore the expression of tyrosine phosphatase containing C-src homology SH-2 (SHP-1 and SHP-2) in benign prostate hyperplasia.

METHODSWith En Vision two-step method, the expression of SHP-1 and SHP-2 was detected in 10 cases of normal prostate tissue, 30 cases of BPH, 20 cases of PIN, 20 cases of high differential Pca and 20 cases of low differential Pca.

RESULTThe expression of SHP-2 in normal group was mainly distributed in the cytoplasm of secretive cells and basal cells, and a little part in the nucleu. In BPH it was distributed equally in the plasm and nucleu. In PIN, high differential Pca and low differential Pca, SHP-2 expressed mainly in nucleu. The average dyeing index of SHP-2 in each group is 0.4, 1.7, 2.1, 2.2 and 2.6. SHP-1 positive expression in normal prostate, BPH, PIN and high differential Pca showed differentiating layer staining in the cytoplasm of secretive cells and basal cells, while not in low differential Pca. The average dyeing index of SHP-1 in each group is 1.8, 1.8, 1.5, 1.2 and 0.4.

CONCLUSIONThere are transformation in signal transduction relation with SHP-1 and SHP-2 in the progress of prostate cell proliferation, differentiation and malignant. The abnormal activation and distribution of SHP-2 might induce prostate reconstruction and hyperplasia, even carcinoma.

Adult ; Aged ; Cell Nucleus ; enzymology ; Cytoplasm ; enzymology ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Prostatic Hyperplasia ; enzymology ; pathology ; Protein Tyrosine Phosphatase, Non-Receptor Type 11 ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; metabolism ; Protein Tyrosine Phosphatases ; metabolism ; SH2 Domain-Containing Protein Tyrosine Phosphatases ; metabolism ; src-Family Kinases ; metabolism

The 1,095 bp gene encoding peroxidase from Coprinus cinereus was synthesized and integrated into the genome of Pichia pastoris with a highly inducible alcohol oxidase. The recombinant CiP (rCiP) fused with the a-mating factor per-pro leader sequence derived from Saccharomyces cerevisiae was secreted into the culture medium and identified as the target protein by mass spectrometry, confirming that a C. cinereus peroxidase (CiP) was successfully expressed in P. pastoris. The endoplasmic reticulum oxidoreductase 1 (Ero1) and protein disulfide isomerase (PDI) were co-expressed with rCiP separately and simultaneously. Compared with the wild type, overexpression of PDI and Erol-PDI increaseed Cip activity in 2.43 and 2.6 fold and their activity reached 316 U/mL and 340 U/mL respectively. The strains co-expressed with Erol-PDI was used to high density fermentation, and their activity reached 3,379 U/mL, which was higher than previously reported of 1,200 U/mL.
Coprinus ; enzymology ; Culture Media ; Cytoplasm ; Fermentation ; Glycoproteins ; metabolism ; Mass Spectrometry ; Mating Factor ; Oxidoreductases Acting on Sulfur Group Donors ; metabolism ; Peptides ; Peroxidases ; biosynthesis ; Pichia ; metabolism ; Protein Disulfide-Isomerases ; metabolism ; Protein Folding ; Saccharomyces cerevisiae ; Saccharomyces cerevisiae Proteins ; metabolism

PURPOSE: Foxo3 in female reproduction has been reported to regulate proliferation of granulose cells that form follicles. There are no reports so far that discuss on the role of Foxo3 in males. This study was designed to outline the role of Foxo3 in the testes. MATERIALS AND METHODS: Testes from mice at birth to postpartum week (PPW) 5 were isolated and examined for the expression of Foxo3 using immunostaining. To elucidate role of Foxo3 in Leydig cells, R2C cells were treated with luteinizing hormone (LH) and the phosphorylation of Foxo3. Testosterone and steroidogenic acute regulatory (StAR) protein levels were measured after constitutive active [triple mutant (TM)] human FOXO3 adenovirus was transduced and StAR promoter assay was performed. RESULTS: Foxo3 expression in the testicles started from birth and lasted until PPW 3. After PPW 3, most Foxo3 expression occurred in the nuclei of Leydig cells; however, at PPW 5, Foxo3 was expressed in both the nucleus and cytoplasm. When R2C cells were treated with luteinizing hormone, Foxo3 phosphorylation levels by AKT increased. After blocking the PI3K pathway, LH-induced phosphorylated Foxo3 levels decreased, indicating that LH signaling regulates Foxo3 localization. When active FOXO3-TM adenovirus was introduced into a Leydig tumor cell line, the concentrations of testosterone and StAR protein decreased. When FOXO3 and a StAR promoter vector were co-transfected into HEK293 cells for a reporter assay, FOXO3 inhibited the StAR promoter. CONCLUSION: FOXO3 affects testosterone synthesis by inhibiting the formation of StAR protein. LH hormone, meanwhile, influences Foxo3 localization, mediating its function.
Animals ; Cell Aging/*physiology ; Cell Nucleus/metabolism ; Cytoplasm/metabolism ; Forkhead Transcription Factors/*metabolism ; HEK293 Cells ; Humans ; Leydig Cells/*drug effects/*enzymology/metabolism ; Luteinizing Hormone/blood ; Male ; Mice ; Phosphatidylinositol 3-Kinases ; Phosphoproteins/metabolism ; Phosphorylation ; Signal Transduction/drug effects ; Testosterone/blood/*metabolism

A marine unicellular green alga, Platymonas subcordiformis, was demonstrated to photobiologically produce hydrogen gas from seawater. The objective of this study was to localize and identify the hydrogenase isolated from P. subcordiformis. Adaptation in the presence of inhibitors of protein biosynthesis indicated that the hydrogenase was much more inhibited by cycloheximide than that by chloramphenicol. The result suggested that the hydrogenase isolated from P. subcordiformis is probably synthesized in cytoplasmic ribosomes. Both Western blot analysis and immunogold electron microscopy demonstrate that the P. subcordiformis hydrogenase is mainly located in the chloroplast stroma. The proteins that reacted specifically with the antibodies against the iron hydrogenase isolated from Chlamydomonas reinhardtii were concentrated by immunoprecipitation. The separated protein bands were cut out of the SDS-PAGE gel, in-gel digested by trypsin, and analyzed by Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). Mascot was employed for analysis of the MALDI data using the public databases NCBInr. The hydrogenase isolated from P. subcordiformis was identified to be the Fe-hydrogenase.
Algal Proteins ; isolation & purification ; metabolism ; Biocatalysis ; drug effects ; Blotting, Western ; Chloramphenicol ; pharmacology ; Chlorophyta ; enzymology ; Cycloheximide ; pharmacology ; Cytoplasm ; enzymology ; ultrastructure ; Electrophoresis, Polyacrylamide Gel ; Hydrogenase ; antagonists & inhibitors ; isolation & purification ; metabolism ; Immunoprecipitation ; methods ; Iron-Sulfur Proteins ; antagonists & inhibitors ; isolation & purification ; metabolism ; Kinetics ; Microscopy, Immunoelectron ; Protein Synthesis Inhibitors ; pharmacology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; methods

Barrett's esophagus is a premalignant condition of esophageal adenocarcinoma. Inducible nitric oxide synthase (iNOS) is induced by cytokines and can generate locally high concentrations of nitric oxide (NO), whose metabolites can mediate genotoxicity and influence multistage carcinogenesis by causing DNA damage. Therefore, we evaluated the immunolocalization and expression of iNOS in surgically induced rat Barrett's esophagus. Esophagoduodenal anastomosis was performed in rats for inducing reflux of duodenal contents. Rats were killed at postoperative 10, 20, 30 and 40 weeks. We examined histologic changes and iNOS expression in esophagus by immunohistochemistry and reverse transcription-poly-merase chain reaction. Eighty six percent of experimental rats showed Barrett's esophagus above esophagoduodenal junction. iNOS immunoreactivity was clearly observed in the epithelial cells of Barrett's esophagus, predominantly at the apical surface of epithelial cells. Cytoplasmic staining was also seen only in atypical Barrett's esophagus. iNOS mRNA was detected only in the lower esophagus of experimental group. In conclusion, this study suggests that iNOS has some roles on Barrett's esophagus formation.
Anastomosis, Surgical ; Animals ; Barrett Esophagus/*enzymology/*surgery ; Cytoplasm/metabolism ; DNA Damage ; Disease Models, Animal ; Duodenum/*enzymology/surgery ; Esophagus/metabolism ; Immunohistochemistry ; Male ; Models, Anatomic ; Neoplasms, Experimental/pathology ; Nitric Oxide/metabolism ; Nitric-Oxide Synthase/*biosynthesis ; RNA/metabolism ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors

Human NUDT16 (hNUDT16) is a decapping enzyme initially identified as the human homolog to the Xenopus laevis X29. As a metalloenzyme, hNUDT16 relies on divalent cations for its cap-hydrolysis activity to remove m⁷GDP and m²²⁷GDP from RNAs. Metal also determines substrate specificity of the enzyme. So far, only U8 small nucleolar RNA (snoRNA) has been identified as the substrate of hNUDT16 in the presence of Mg²(+). Here we demonstrate that besides U8, hNUDT16 can also actively cleave the m⁷GDP cap from mRNAs in the presence of Mg²(+) or Mn²(+). We further show that hNUDT16 does not preferentially recognize U8 or mRNA substrates by our cross-inhibition and quantitative decapping assays. In addition, our mutagenesis analysis identifies several key residues involved in hydrolysis and confirms the key role of the REXXEE motif in catalysis. Finally an investigation into the subcellular localization of hNUDT16 revealed its abundance in both cytoplasm and nucleus. These findings extend the substrate spectrum of hNUDT16 beyond snoRNAs to also include mRNA, demonstrating the pleiotropic decapping activity of hNUDT16.
Amino Acid Motifs ; Biocatalysis ; Cell Nucleus ; enzymology ; Consensus Sequence ; Cytoplasm ; enzymology ; metabolism ; Guanosine Diphosphate ; metabolism ; Histidine ; metabolism ; Humans ; Hydrolysis ; Luciferases ; genetics ; Magnesium ; metabolism ; Manganese ; metabolism ; Mutagenesis ; Mutation ; Pyrophosphatases ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; RNA Caps ; chemistry ; metabolism ; pharmacology ; RNA, Small Nucleolar ; chemistry ; metabolism ; pharmacology

OBJECTIVETo investigate the effects of protein tyrosine kinase (PTK), protein tyrosine phosphatase (PTP) and protein kinase C (PKC) on apoptosis and observe the changes of cytosolic calcium ([Ca(2+)]i) of arsenic trioxide (As2O3) treated human leukemia cells NB4 and cortex neurons.

METHODS[Ca(2+)]i of NB4 cells and cortex neurons was probed with Fluo-3/AM, its changes were assayed with laser confocal microscopy in real-time after As2O3 treatment at different concentrations, the effects of PTK and PTP and the activation of PKC on these changes with confocal microscopy and phosphorus radioisotope assay. DNA ladders of NB4 cells and cortex neurons after exposed to As2O3 were observed.

RESULTSAs2O3 at 1 micromol/L could remarkably increase the [Ca(2+)]i of NB4 cells but had no effects on neurons. Vanadate, a kind of PTP inhibitor, could promote the increase of [Ca(2+)]i treated by 2, 5, 10 micromol/L As2O3 in a dose-dependent manner. The mean total increase rates at 240 seconds after exposed to As2O3 at different concentrations were (6.5 +/- 2.3)%, (21.7 +/- 2.1)%, (49.2 +/- 2.5)% for NB4 cells, and (6.7 +/- 2.1)%, (19.4 +/- 2.5)%, (52.3 +/- 2.7)% for cortex neurons, respectively. Genistein, a kind of PTK inhibitor, could decrease the increase of [Ca(2+)]i treated by 2, 5, 10 micromol/L As2O3 in a dose-dependent manner. The mean total inhibited rates at 240 seconds after As2O3 treatment at different concentrations were (6.7 +/- 2.9)%, (25.6 +/- 2.5)%, (52.2 +/- 3.5)% for NB4 cells, and (7.8 +/- 3.1)%, (18.1 +/- 2.8)%, (51.3 +/- 3.3)% for cortex neurons, respectively. The activation of PKC began to increase as exposed to As2O3 at 1 micromol/L for 3 h, and kept rising continuously in NB4 cells and at 24 h DNA ladders emerged. However, none of the above results was found in human cortex neurons, but when exposed to 2 micromol/L As2O3, the activation of PKC and DNA ladders did emerge in neurons.

CONCLUSIONSThe phosphorylation and dephosphorylation of PTK and PTP participated in nonspecific apoptosis signal transduction pathway related to As2O3, and accompanied with PKC activation. The [Ca(2+)]i elevation was closely related to increased PKC activation. There existed difference in dose tolerances to As2O3 between NB4 cell and cortex neurons.

Adult ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Calcium ; metabolism ; Cell Line, Tumor ; Cells, Cultured ; Cerebral Cortex ; cytology ; Cytoplasm ; metabolism ; Dose-Response Relationship, Drug ; Humans ; Leukemia, Promyelocytic, Acute ; enzymology ; metabolism ; pathology ; Male ; Neurons ; cytology ; drug effects ; metabolism ; Oxides ; pharmacology ; Protein Kinase C ; metabolism ; Protein Tyrosine Phosphatases ; metabolism ; Protein-Tyrosine Kinases ; metabolism