References of "Czerniecki, Jan"
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See detailPig tissues express a catalytically inefficient 25-kDa thiamine triphosphatase: Insight in the catalytic mechanisms of this enzyme
Szyniarowski, Piotr; Lakaye, Bernard ULg; Czerniecki, Jan ULg et al

in Biochimica et Biophysica Acta - General Subjects (2005), 1725(1), 93-102

Thiamine triphosphate (ThTP) is found in most organisms and may be an intracellular signal molecule produced in response to stress. We have recently cloned the cDNA coding for a highly specific mammalian ... [more ▼]

Thiamine triphosphate (ThTP) is found in most organisms and may be an intracellular signal molecule produced in response to stress. We have recently cloned the cDNA coding for a highly specific mammalian 25-kDa thiamine triphosphatase. The enzyme was active in all mammalian species studied except pig, although the corresponding mRNA was present. In order to determine whether the very low ThTPase activity in pig tissues is due to the absence of the protein or to a lack of catalytic efficiency, we expressed human and pig ThTPase in E. coli as GST fusion proteins. The purified recombinant pig GST-ThTPase was found to be 2-3 orders of magnitude less active than human GST-ThTPase. Using site-directed mutagenesis, we show that, in particular, the change of Glu85 to lysine is responsible for decreased solubility and catalytic activity of the pig enzyme. Immunohistochemical studies revealed a distribution of the protein in pig brain very similar to the one reported in rodent brain. Thus, our results suggest that a 25-kDa protein homologous to hThTPase but practically devoid of enzyme activity is expressed in pig tissues. This raises the possibility that this protein may play a physiological role other than ThTP hydrolysis. [less ▲]

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See detailNeuronal localization of the 25-kDa specific thiamine triphosphatase in rodent brain
Czerniecki, Jan ULg; Chanas, Grazyna; Verlaet, Myriam ULg et al

in Neuroscience (2004), 125(4), 833-840

Thiamine triphosphate (ThTP) is found in small amounts in most organisms from bacteria to mammals, but little is known about its physiological role. In vertebrate tissues, ThTP may act as a phosphate ... [more ▼]

Thiamine triphosphate (ThTP) is found in small amounts in most organisms from bacteria to mammals, but little is known about its physiological role. In vertebrate tissues, ThTP may act as a phosphate donor for the phosphorylation of certain proteins; this may be part of a new signal transduction pathway. We have recently characterized a highly specific 25-kDa thiamine triphosphatase (ThTPase) that is expressed in most mammalian tissues. The role of this enzyme may be the control of intracellular concentrations of ThTP. As the latter has been considered to be a neuroactive form of thiamine, we have studied the distribution of ThTPase mRNA and protein in rodent brain using in situ hybridization and immunohistochemistry. With both methods, we found the strongest staining in hippocampal pyramidal neurons, as well as cerebellar granule cells and Purkinje cells. Some interneurons were also labeled and many ThTPase mRNA-positive and immunoreactive cells were distributed throughout cerebral cortical gray matter and the thalamus. White matter was not significantly labeled. ThTPase immunoreactivity seems to be located mainly in the cytoplasm of neuronal perikarya. Immunocytochemical data using dissociated cultured cells from hippocampal and cerebellum showed that the staining was more intense in neurons than in astrocytes. The protein was rather uniformly located in the perikarya and dendrites, suggesting that ThTP and ThTPase may play a general role in neuronal metabolism rather than a specific role in excitability. There was no apparent correlation between ThTPase expression and selective vulnerability of certain brain regions to thiamine deficiency. (C) 2004 IBRO. Published by Elsevier Ltd. All rights reserved. [less ▲]

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See detailExpression of 25 kDa thiamine triphosphatase in rodent tissues using quantitative PCR and characterization of its mRNA
Lakaye, Bernard ULg; Verlaet, Myriam ULg; Dubail, Johanne ULg et al

in International Journal of Biochemistry & Cell Biology (2004), 36(10), 2032-2041

Thiamine triphosphate (ThTP) is found in most organisms, but its biological role remains unclear. In mammalian tissues, cellular ThTP concentrations remain low, probably because of hydrolysis by a ... [more ▼]

Thiamine triphosphate (ThTP) is found in most organisms, but its biological role remains unclear. In mammalian tissues, cellular ThTP concentrations remain low, probably because of hydrolysis by a specific 25 kDa thiamine triphosphatase (ThTPase). The aim of the present study was to use quantitative PCR, for comparing the 25 kDa ThTPase mRNA expression in various mouse tissues with its enzyme activities. ThTPase mRNA was expressed at only a few copies per cell. The highest amount of mRNA was found in testis, followed by lung and muscle, while the highest enzyme activities were found in liver and kidney. The poor correlation between mRNA levels and enzyme activities might result either from tissue-specific post-transcriptional regulation of mRNA processing and/or translation or from the regulation of enzyme activities by post-translational mechanisms. Purified recombinant human ThTPase was phosphorylated by casein kinase 11, but this phosphorylation did not modify the enzyme activity. However, the characterization of the 3'-untranslated mRNA region revealed a unique, highly conserved, 200-nucleotide sequence that might be involved in translational control. In situ hybridization studies in testis suggest a predominant localization of ThTPase mRNA in poorly differentiated spermatogenic cells. This is the first study demonstrating a cell-specific 25 kDa ThTPase mRNA expression, suggesting that this enzyme might be related to the degree of differentiation or the metabolic state of the cell. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailThiamine triphosphate and thiamine triphosphatase activities: from bacteria to mammals
Makarchikov, Alexander F; Lakaye, Bernard ULg; Gulyai, I. E. et al

in Cellular and Molecular Life Sciences : CMLS (2003), 60(7), 1477-1488

In most organisms, the main form of thiamine is the coenzyme thiamine diphosphate. Thiamine triphosphate (ThTP) is also found in low amounts in most vertebrate tissues and can phosphorylate certain ... [more ▼]

In most organisms, the main form of thiamine is the coenzyme thiamine diphosphate. Thiamine triphosphate (ThTP) is also found in low amounts in most vertebrate tissues and can phosphorylate certain proteins. Here we show that ThTP exists not only in vertebrates but is present in bacteria, fungi, plants and invertebrates. Unexpectedly, we found that in Escherichia coli as well as in Arabidopsis thaliana, ThTP was synthesized only under particular circumstances such as hypoxia (E. coli) or withering (A. thaliana). In mammalian tissues, ThTP concentrations are regulated by a specific thiamine triphosphatase that we have recently characterized. This enzyme was found only in mammals. In other organisms, ThTP can be hydrolyzed by unspecific phosphohydrolases. The occurrence of ThTP from prokaryotes to mammals suggests that it may have a basic role in cell metabolism or cell signaling. A decreased content may contribute to the symptoms observed during thiamine deficiency. [less ▲]

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