Abstract
Signal transducer and activator of transcription 3 (STAT3) is a latent cytoplasmic transcription factor that can be activated by cytokines and growth factors. It plays important roles in cell growth, apoptosis and cell transformation, and is constitutively active in a variety of tumor cells. In this study, we provide evidence that zipper-interacting protein kinase (ZIPK) interacts physically with STAT3. ZIPK specifically interacted with STAT3, and did not bind to STAT1, STAT4, STAT5a, STAT5b or STAT6. ZIPK phosphorylated STAT3 on serine 727 (Ser727) and enhanced STAT3 transcriptional activity. Small interfering RNA-mediated reduction of ZIPK expression decreased leukemia inhibitory factor (LIF)- and IL-6-induced STAT3-dependent transcription. Furthermore, LIF- and IL-6-mediated STAT3 activation stimulated ZIPK activity. Taken together, our data suggest that ZIPK interacts with STAT3 within the nucleus to regulate the transcriptional activity of STAT3 via phosphorylation of Ser727.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Apoptosis Regulatory Proteins
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Calcium-Calmodulin-Dependent Protein Kinases
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Cell Line, Tumor
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Death-Associated Protein Kinases
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Enzyme Activation / drug effects
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Enzyme Activation / genetics
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Enzyme Activation / immunology
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Humans
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Interleukin-6 / pharmacology
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Leukemia Inhibitory Factor
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Phosphorylation / drug effects
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Protein Binding / genetics
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Protein Binding / immunology
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Protein Processing, Post-Translational / drug effects
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Protein Processing, Post-Translational / genetics
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Protein Processing, Post-Translational / immunology
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / immunology*
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Protein Serine-Threonine Kinases / metabolism
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STAT3 Transcription Factor / genetics
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STAT3 Transcription Factor / immunology*
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STAT3 Transcription Factor / metabolism
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Signal Transduction / drug effects
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Signal Transduction / immunology*
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Transcription, Genetic / drug effects
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Transcription, Genetic / genetics
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Transcription, Genetic / immunology
Substances
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Apoptosis Regulatory Proteins
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IL6 protein, human
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Interleukin-6
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LIF protein, human
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Leukemia Inhibitory Factor
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STAT3 Transcription Factor
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STAT3 protein, human
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Death-Associated Protein Kinases
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Protein Serine-Threonine Kinases
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Calcium-Calmodulin-Dependent Protein Kinases