| Autor: |
Sauvonnet, Nathalie, Lambermont, Isabelle, Bruggen, Pierre van der, Cornelis, Guy R. |
| Předmět: |
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| Zdroj: |
Molecular Microbiology; Aug2002, Vol. 45 Issue 3, p805-815, 11p |
| Abstrakt: |
Summary Phosphatidylinositol 3-kinase (PI 3-kinase) and its target protein kinase B (Akt) are involved in various processes including internalization, chemotaxis and proliferation. We analysed the activation of Akt in J774 macrophages infected with virulent (pYV+ ) or avirulent (pYV - ) Yersinia enterocolitica . During the early stage of infection with pYV + and pYV - bacteria, Akt and its targets, glycogen synthase kinase 3 (GSK-3) and forkhead transcription factor (FKHRL1), became phosphorylated. This phosphorylation induction was inhibited by wortmannin and thus dependent on PI 3-kinase. When infection was carried out with pYV + bacteria but not with pYV - bacteria, Akt and its targets became dephosphorylated at later time points. Using single knock-out mutants in bacterial effector genes, we have determined that the tyrosine phosphatase YopH was responsible for the inactivation of the PI 3-kinase cascade. In macrophages, this inactivation correlated with the downregulation of mRNA coding for monocyte chemoattractant protein 1 (MCP-1), suggesting that YopH inhibits recruitment of macrophages to lymph nodes. We also analysed the effects of Y. enterocolitica infection on the proliferation of T lymphocytes. Consistent with the observation that YopH inactivated the Akt pathway, YopH inhibited PI 3-kinase-dependent secretion of interleukin 2 and proliferation. These data reveal a new effect of YopH in Yersinia pathogenesis. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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