Vanadate inhibition of protein tyrosine phosphatases in Jurkat cells: modulation by redox state
| Autor: | Michael J. Gresser, Nancy Detich, Cary Cuncic, Diane Ethier, Alan S. Tracey, Chidambaran Ramachandran |
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| Rok vydání: | 1999 |
| Předmět: |
Cell type
Kinase Protein tyrosine phosphatase Glutathione environment and public health Biochemistry Jurkat cells Redox In vitro Cell biology Inorganic Chemistry enzymes and coenzymes (carbohydrates) chemistry.chemical_compound Jurkat Cells chemistry Calcium-Calmodulin-Dependent Protein Kinases Dinitrochlorobenzene Humans Leukocyte Common Antigens Vanadate Phosphorylation Protein Tyrosine Phosphatases Vanadates Oxidation-Reduction |
| Zdroj: | Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry. 4(3) |
| ISSN: | 0949-8257 |
| Popis: | Vanadate is a potent reversible inhibitor of protein tyrosine phosphatases (PTP) in vitro. Vanadate has been shown to increase the phosphotyrosine levels in some cell types whereas in others, like the Jurkat T-lymphoma, vanadate has no effect. The reason for the apparent lack of effect of vanadate in Jurkat cells was investigated in this study. Alteration of the redox state of these cells by reducing the glutathione level with 1-chloro-2,4-dinitrobenzene (DnpCl) had no effect on phosphotyrosine levels. However, the cells became sensitive to vanadate, as measured by an increase in phosphotyrosine levels on a wide range of proteins including the MAP kinases. The increase in phosphotyrosine levels most likely results from inhibition of cellular PTP and suggests that protein tyrosine kinases are constitutively active in cells, resulting in a dynamic phosphorylation-dephosphorylation cycle. The mode of inhibition of PTP by vanadate was investigated by measuring the PTP activity of Jurkat membranes isolated after treatment of cells with vanadate and DnpCl. In contrast to the reversible inhibition of PTP in vitro, the effect of vanadate in the presence of DnpCl was irreversible, raising the possibility that it is peroxovanadate formed in situ that is responsible for the inhibition of PTP in intact cells. |
| Databáze: | OpenAIRE |
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