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  • 1
    Electronic Resource
    Electronic Resource
    Ornithine transcarbamylase in liver mitochondria (1982)
    Springer
    Molecular and cellular biochemistry 49 (1982), S. 97-111 
    Details
    ISSN: 1573-4919
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Ornithine transcarbamylase (ornithine carbamoyltransferase, EC 2.1.3.3), the second enzyme of urea synthesis, is localized in the matrix of liver mitochondria of ureotelic animals. The enzyme is encoded by a nuclear gene, synthesized outside the mitochondria, and must then be transported into the organelle. The rat liver enzyme is initially synthesized on membrane-free polysomes in the form of a larger precursor with an amino-terminal extension of 3 400–4 000 daltons. In rat liver slices and isolated rat hepatocytes, the pulse-labeled precursor is first released into the cytosol and is then transported with a half life of 1 2 min into the mitochondria where it is proteolytically processed to the mature form of the enzyme. The precursor synthesized in vitro exists in a highly aggregated form and has a conformation different from that of the mature enzyme. The precursor has an isoelectric point (pI = 7.9) higher than that of the mature enzyme (pI = 7.2). The precursor synthesized in vitro can be taken up and processed to the mature enzyme by isolated rat liver mitochondria. The mitochondrial transport and processing system requires membrane potential and a high integrity of the mitochondria. The transport and processing activities are conserved between mammals and birds or amphibians and is presumably common to more than one precursor. Potassium ion, magnesium ion, and probably a cytosolic protein(s), in addition to the transcarbamylase precursor and the mitochondria, are required for the maximal transport and processing of the precursor. A mitochondrial matrix protease which converts the precursor to a product intermediate in size between the precursor and the mature subunit has been highly purified. The protease has an estimated molecular weight of 108 000 and an optimal pH of 7.5–8.0, and appears to be a metal protease. The protease does not cleave several of the protein and peptide substrates tested. The role of this protease in the precursor processing remains to be elucidated. Rats subjected to different levels of protein intake and to fasting show significant changes in the level of enzyme protein and activity of ornithine transcarbamylase. The dietary-dependent changes in the enzyme level are due mainly to an altered level of functional mRNA for the enzyme. In contrast, during fasting, the increase in the enzyme level is associated with a decreased level of translatable mRNA forthe enzyme. Pathological aspects of ornithine transcarbamylase including the enzyme deficiency and reduced activities of the enzyme in Reye's syndrome are also described. A possibility that impaired transport of the enzyme precursor into the mitochondria leads to a reduced enzyme activity, is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00242488
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  • 2
    Electronic Resource
    Electronic Resource
    Differential expression of CCAAT enhancer binding protein family in rat alveolar epithelial cell proliferation and in acute lung injury (1999)
    Springer
    Cell & tissue research 297 (1999), S. 261-270 
    Details
    ISSN: 1432-0878
    Keywords: Key words Acute lung injury ; Bleomycin ; CCAAT enhancer binding protein ; Lipopolysaccharide ; Wound healing ; Rat (F 344)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Although alveolar reorganization after acute lung injury depends on regeneration of alveolar epithelial cells, there is little knowledge of regulation of pulmonary healing process. Transcription factors may play key roles in this regulation. To investigate whether the CCAAT enhancer binding protein (C/EBP) family, α, β, and δ, were involved in alveolar reorganization after injury, we examined expression of C/EBP proteins and mRNAs in lung injuries induced by lipopolysaccharide (LPS) or bleomycin (Bleo) and in cell proliferation by keratinocyte growth factor (KGF). By immunohistochemistry, we demonstrated that C/EBPα and C/EBPβ were expressed in alveolar type II cells and alveolar macrophages, but C/EBPδ was expressed restrictedly in some of alveolar type II cells in a spatial pattern in the control lungs. Further, these three C/EBP family members were differentially expressed in alveolar cell proliferation and in acute lung injury, in which, interestingly, C/EBPα and C/EBPδ were reciprocally expressed in alveolar type II cell proliferation and in pulmonary fibrosis. However, expressions of their mRNAs by in situ hybridization were dramatically increased in the affected lesions of the lungs by LPS and Bleo, and Northern blot analysis showed an increased abundance of the mRNA for C/EBPβ in LPS-treated lungs and for C/EBPδ in Bleo-treated lungs, compared with those in the control lungs. Thus, differential expression of the C/EBP family may be required to maintain and reorganize the basic integrity of alveolar structure during pathological states, which suggests an important role for the C/EBP family in maintaining normal alveolar architecture and function and in repairing the damaged epithelium after injury.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051354
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  • 3
    Electronic Resource
    Electronic Resource
    Immunohistochemical Localization of Arginase II and Other Enzymes of Arginine Metabolism in Rat Kidney and Liver (1998)
    Springer
    Journal of molecular histology 30 (1998), S. 741-751 
    Details
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Arginine is a precursor for the synthesis of urea, polyamines, creatine phosphate, nitric oxide and proteins. It is synthesized from ornithine by argininosuccinate synthetase and argininosuccinate lyase and is degraded by arginase, which consists of a liver-type (arginase I) and a non-hepatic type (arginase II). Recently, cDNAs for human and rat arginase II have been isolated. In this study, immunocytochemical analysis showed that human arginase II expressed in COS-7 cells was localized in the mitochondria. Arginase II mRNA was abundant in the rat small intestine and kidney. In the kidney, argininosuccinate synthetase and lyase were immunostained in the cortex, intensely in proximal tubules and much less intensely in distal tubules. In contrast, arginase II was stained intensely in the outer stripes of the outer medulla, presumably in the proximal straight tubules, and in a subpopulation of the proximal tubules in the cortex. Immunostaining of serial sections of the kidney showed that argininosuccinate synthetase and arginase II were collocalized in a subpopulation of proximal tubules in the cortex, whereas only the synthetase, but not arginase II, was present in another subpopulation of proximal tubules. In the liver, all the enzymes of the urea cycle, i.e. carbamylphosphate synthetase I, ornithine transcarbamylase, argininosuccinate synthetase and lyase and arginase I, showed similar zonation patterns with staining more intense in periportal hepatocytes than in pericentral hepatocytes, although zonation of ornithine transcarbamylase was much less prominent. The implications of these results are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003468726969
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  • 4
    Electronic Resource
    Electronic Resource
    Sequence heterogeneity of human liver arginase cDNAs and restriction fragment length polymorphism of the gene locus (1988)
    Springer
    Journal of human genetics 33 (1988), S. 305-313 
    Details
    ISSN: 1435-232X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Arginase is an enzyme involved in the urea cycle and its deficiency results in argininemia, an autosomal recessive disorder accompanied by hyperammonemia. We isolated two overlapping cDNA clones and determined the entire nucleotide sequence (Haraguchiet al. 1987.Proc. Natl. Acad. Sci. USA 84: 412–415). Sequence analysis of eight cDNA clones revealed nucleotide variations at five positions in the protein coding region, and all these variations were accompanied by amino acid substitutions (Met to Lys at amino acid residue 1, Gln to Glu at residue 86, Ser to Phe at residue 109, Leu to Gln at residue 206, and Val to Ala at residue 233). These results suggest that human liver arginase is polymorphic in amino acid sequence, although some of the variations may be due to a transcription error or to cloning artifacts. Two restriction fragment length polymorphisms were identified at the arginase gene locus, using restriction endonucleasePvuII andHincII. These sequence polymorphisms and restriction fragment length polymorphisms may serve as linkage markers for arginase deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02032860
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  • 5
    Electronic Resource
    Electronic Resource
    Evolutionary aspects of urea cycle enzyme genes (1989)
    New York, NY : Wiley-Blackwell
    BioEssays 10 (1989), S. 163-166 
    Details
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The functions and expression pattern of urea cycle enzymes have undergone considerable changes during the course of evolution. Sequence analyses shows that urea cycle enzymes from mammals are homologous to microbial enzymes of the arginine-metabolic pathway. Recently, an unexpected relationship was found between argininosuccinate lyase (EC 4.3.2.1), the fourth enzyme of the cycle, and δ-crystallin, a lens structural protein of birds and reptiles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bies.950100506
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  • 6
    Electronic Resource
    Electronic Resource
    Tissue- and developmental stage-specific expression of the rat ornithine carbamoyltransferase gene in transgenic mice (1989)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 10 (1989), S. 393-401 
    Details
    ISSN: 0192-253X
    Keywords: Urea cycle enzyme ; Tissue-specific expression ; Developmental regulation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rat ornithine carbamoyltransferase (OCT; EC 2.1.3.3) is encoded by a large gene of 75 kilobases. Expression of this gene is restricted to the liver and small intestine, and there is an increase in expression late in gestation. The recombinant gene carrying 1.3 kilobases of the 5′ flanking region of the gene fused to the rat OCT cDNA was microinjected into fertilized eggs, and 17 transgenic mice were produced. Expression in the liver of the transgene was detected in three mice. In these mice, the transgene expression was observed exclusively in the liver and small intestine. Expression of the transgene in the intestine was comparable to that of the endogenous mouse OCT gene, whereas expression in the liver was much lower than that of the endogenous gene. The developmental pattern of expression of the transgene was similar to that of the endogenous gene. Therefore, the 5′ flanking sequence of the rat OCT gene seems to be sufficient for the developmental and tissue-specific expression of the gene. An explanation for low expression in the liver remains the subject of ongoing study.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020100507
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  • 7
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    Activation of the Dickkopf1-CKAP4 pathway is associated with poor prognosis of esophageal cancer and anti-CKAP4 antibody may be a new therapeutic drug (2018)
    Nature Publishing Group (NPG)
    In: Oncogene
    Details
    Publication Date: 2018-03-22
    Description: Activation of the Dickkopf1-CKAP4 pathway is associated with poor prognosis of esophageal cancer and anti-CKAP4 antibody may be a new therapeutic drug Activation of the Dickkopf1-CKAP4 pathway is associated with poor prognosis of esophageal cancer and anti-CKAP4 antibody may be a new therapeutic drug, Published online: 22 March 2018; doi:10.1038/s41388-018-0179-2 Activation of the Dickkopf1-CKAP4 pathway is associated with poor prognosis of esophageal cancer and anti-CKAP4 antibody may be a new therapeutic drug
    Print ISSN: 0950-9232
    Topics: Medicine
    Published by Nature Publishing Group (NPG)
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  • 8
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    New findings of kinase switching in gastrointestinal stromal tumor under imatinib using phosphoproteomic analysis (2013)
    Wiley-Blackwell
    Details
    Publication Date: 2013-05-29
    Description: Despite the revolutionary effects of imatinib on advanced gastrointestinal stromal tumors (GISTs), most patients eventually develop disease progression following primary resistance or acquired resistance driven by secondary-resistant mutations. Even in radiographically vanishing lesions, pathology has revealed persistent viable cells during imatinib therapy, which could lead to the emergence of drug-resistant clones. To uncover the mechanisms underlying these clinical issues, here we examined imatinib-induced phosphoproteomic alterations in GIST-T1 cells, using our quantitative tyrosine phosphoproteomic analysis method, which combined immunoaffinity enrichment of phosphotyrosine-containing peptides with iTRAQ technology. Using this approach, we identified 171 tyrosine phosphorylation sites spanning 134 proteins, with 11 proteins exhibiting greater than 1.5-fold increases in tyrosine phosphorylation. Among them, we evaluated FYN and focal adhesion kinase (FAK), both of which are reportedly involved in proliferation and malignant alteration of tumors. We confirmed increased tyrosine phosphorylation of both kinases by western blotting. Inhibition of FYN and FAK phosphorylation each increased tumor cell sensitivity to imatinib. Furthermore, a FAK-selective inhibitor (TAG372) induced apoptosis of imatinib-resistant GIST-T1 cells and decreased the imatinib IC 50 . These results indicate that FYN or FAK might be potential therapeutic targets to overcome resistance to imatinib in GISTs. Additionally, we showed that the iTRAQ-based quantitative phosphotyrosine-focused phosphoproteomic approach is a powerful method for screening phosphoproteins associated with drug resistance. © 2013 Wiley Periodicals, Inc.
    Print ISSN: 0020-7136
    Electronic ISSN: 1097-0215
    Topics: Biology , Medicine
    Published by Wiley-Blackwell
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