Granulocyte colony-stimulating factor rapidly activates a distinct STAT-like protein in normal myeloid cells
| Autor: | D J, Tweardy, T M, Wright, S F, Ziegler, H, Baumann, A, Chakraborty, S M, White, K F, Dyer, K A, Rubin |
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| Rok vydání: | 1995 |
| Předmět: |
B-Lymphocytes
Enzyme Precursors Base Sequence Transcription Genetic Macromolecular Substances Neutrophils Molecular Sequence Data Intracellular Signaling Peptides and Proteins Cell Differentiation Protein-Tyrosine Kinases Hematopoietic Stem Cells Recombinant Proteins Cell Line DNA-Binding Proteins Interferon-gamma src-Family Kinases Gene Expression Regulation Granulocyte Colony-Stimulating Factor Trans-Activators Humans Syk Kinase Cells Cultured Protein Binding Signal Transduction |
| Zdroj: | Blood. 86(12) |
| ISSN: | 0006-4971 |
| Popis: | Binding of granulocyte colony-stimulating factor (G-CSF) to normal myeloid cells activates the protein tyrosine kinases Lyn and Syk and results in the immediate early upregulation of G-CSF receptor (R) mRNA. In our studies of the signaling pathways activated by G-CSF that are coupled to proliferation and differentiation of myeloid cells, we examined whether G-CSF activated a latent transcription factor belonging to the STAT protein family. Electrophoretic mobility shift assays (EMSAs) of nuclear extracts from G-CSF-stimulated human myeloid cells showed the rapid activation of a DNA-binding protein that bound to the high-affinity serum-inducible element (hSIE) and migrated with mobility similar to serum inducible factor (SIF)-A (Stat3 homodimer). The G-CSF-stimulated SIF-A complex (G-SIF-A) did not bind to duplex oligonucleotides used to purify and characterize other Stat proteins (Stat1-6). In addition, antibodies raised against Stat1-6 failed to supershift the G-SIF-A complex or interfere with its formation. Based on its binding to the hSIE and lack of antigenic cross-reactivity with other known STAT proteins that bind to this element, it is likely that G-SIF-A is composed of a distinct member of the STAT protein family. EMSAs of whole-cell extracts prepared from cell lines containing full-length and truncated mutants of the G-CSFR showed that activation of G-SIF-A did not correlate with proliferation; rather, optimal activation requires the distal half of the cytosolic domain of the G-CSFR that is essential for differentiation. Activation of G-SIF-A, therefore, may be an early G-CSFR-coupled event that is critical for myeloid maturation. |
| Databáze: | OpenAIRE |
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