TY - JOUR
T1 - YopH prevents monocyte chemoattractant protein 1 expression in macrophages and T-cell proliferation through inactivation of the phosphatidylinositol 3-kinase pathway
AU - Sauvonnet, Nathalie
AU - Lambermont, Isabelle
AU - van der Bruggen, Pierre
AU - Cornelis, Guy R
PY - 2002
Y1 - 2002
N2 - 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.
AB - 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.
M3 - Article
C2 - 12139625
SN - 0950-382X
VL - 45
SP - 805
EP - 815
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 3
ER -