Abstract
The growth and differentiation of megakaryocytes are regulated by thrombopoietin (TPO), a recently characterized cytokine which exerts its effects via a member of the hematopoietin receptor superfamily, c-Mpl. Since many cytokines which bind hematopoietin receptors activate the STAT family of transcription factors, we investigated whether STAT proteins were activated by TPO. TPO induced the formation of a DNA-binding complex recognizing a known STAT-binding sequence. STAT5 was a major component of this DNA-binding complex, and STAT5 was tyrosine phosphorylated in response to TPO. Additionally, TPO-induced the tyrosine phosphorylation and DNA-binding activity of STAT3. Together with the recent demonstration of JAK2 activation in response to TPO, the data presented here define a rapid signaling pathway likely to be important in TPO-induced gene regulation.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Base Sequence
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Binding Sites
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Cell Differentiation / drug effects
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Cell Division / drug effects
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Cell Line
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Cytokines / pharmacology*
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DNA-Binding Proteins / isolation & purification
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DNA-Binding Proteins / metabolism*
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Enzyme Activation
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Humans
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Janus Kinase 2
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Leukemia, Megakaryoblastic, Acute
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Megakaryocytes / cytology
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Megakaryocytes / drug effects
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Megakaryocytes / metabolism
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Milk Proteins*
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Molecular Sequence Data
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Oligodeoxyribonucleotides
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Phosphorylation
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Phosphotyrosine
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Protein-Tyrosine Kinases / metabolism*
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Proto-Oncogene Proteins*
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Recombinant Proteins / pharmacology
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STAT3 Transcription Factor
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STAT5 Transcription Factor
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Signal Transduction
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Thrombopoietin / pharmacology*
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Trans-Activators / metabolism*
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Tumor Cells, Cultured
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Tyrosine / analogs & derivatives
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Tyrosine / metabolism
Substances
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Cytokines
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DNA-Binding Proteins
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Milk Proteins
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Oligodeoxyribonucleotides
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Proto-Oncogene Proteins
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Recombinant Proteins
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STAT3 Transcription Factor
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STAT3 protein, human
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STAT5 Transcription Factor
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Trans-Activators
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Phosphotyrosine
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Tyrosine
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Thrombopoietin
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Protein-Tyrosine Kinases
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JAK2 protein, human
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Janus Kinase 2