[H2O2-induced activation of transcription factors STAT1 and STAT3: the role of EGF receptor and tyrosine kinase JAK2].
Reactive oxygen species initiate multiple signal transduction pathways including tyrosine kinase signaling. Here, we demonstrate tyrosine phosphorylation of EGF receptor, STAT3, and, to a lesser extent, STAT1 upon H2O2 treatment of HER14 cells (NIH3T3 fibroblasts transfected with full-length EGF receptor). Maximum phosphorylation levels were observed in 5 min of stimulation at 1-2 mM H2O2. It has been shown that the intrinsic EGF-receptor tyrosine kinase is responsible for the receptor phosphorylation upon H2O2 stimulation. STAT3 and STAT1 activation in HER14 cells was demonstrated to depend on EGF receptor kinase activity, rather than JAK2 activity, while in both K721A and CD126 cells (NIH3T3 transfected with kinase-dead EGF receptor, and EGF receptor lacking major autophosphorylation sites, respectively) STAT1 and STAT3 tyrosine phosphorylation requires JAK2 kinase activity. Furthermore, STAT3 is constitutively phosphorylated in K721A and CD126 cells, and STAT1 H2O2-stimulated activation in these cells is much more prominent than in HER14. In all the cell lines used, Src-kinase activity was demonstrated to be unnecessary for ROS-initiated phosphorylation of STATs. Herein, we postulate that EGF receptor plays a role in H2O2-induced STAT activation in HER14 cells. Our data also prompted a hypothesis of constitutive inhibition of JAK2-dependent STAT activation in this cell line.
Burova
E B
EB
Institute of Cytology RAS, St. Petersburg. burova.e@mailcity.com
Grudinkin
P S
PS
Bardin
A A
AA
Gamaleĭ
N N
NN
D016475:3T3 Cells; D000818:Animals; D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D053614:Janus Kinase 2; D051379:Mice; D018345:Mice, Knockout; D018384:Oxidative Stress; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; C494080:Stat1 protein, mouse; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D014443:Tyrosine; D006861:Hydrogen Peroxide; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2