The Activated Form of the Lck Tyrosine Protein Kinase in Cells Exposed to Hydrogen Peroxide Is Phosphorylated at Both Tyr-394 and Tyr-505
| Autor: | Bartholomew M. Sefton, James S. Hardwick |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
inorganic chemicals
T-Lymphocytes Blotting Western Protein tyrosine phosphatase SH2 domain Biochemistry Catalysis Receptor tyrosine kinase SH3 domain Jurkat Cells Animals Humans Protein phosphorylation Src family kinase Phosphorylation Molecular Biology Tyrosine-protein kinase CSK biology Chemistry Hydrogen Peroxide Cell Biology Fibroblasts Rats Enzyme Activation Lymphocyte Specific Protein Tyrosine Kinase p56(lck) biology.protein Tyrosine Proto-oncogene tyrosine-protein kinase Src |
| Zdroj: | Journal of Biological Chemistry. 272:25429-25432 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.272.41.25429 |
| Popis: | Members of the Src family of non-receptor tyrosine protein kinases are known to be inhibited by the intramolecular association between a phosphorylated carboxyl-terminal tyrosine residue and the SH2 domain. We have previously shown that exposure of cells to H2O2 strongly activates Lck, a lymphocyte-specific Src family kinase, by inducing phosphorylation on Tyr-394, an absolutely conserved residue within the activation loop of the catalytic domain. Here we show that Lck that has been activated by H2O2 is simultaneously phosphorylated at both the carboxyl-terminal tyrosine (Tyr-505) and Tyr-394. Thus, dephosphorylation of Tyr-505 is not a prerequisite for either phosphorylation of Lck at Tyr-394 or catalytic activation of the kinase. These results indicate that activation of Lck by phosphorylation of Tyr-394 is dominant over any inhibition induced by phosphorylation of Tyr-505. We propose that these results may be extended to all Src family members. |
| Databáze: | OpenAIRE |
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