title: Delineation and mapping of Stat5 isoforms activated by granulocyte colony-stimulating factor in myeloid cells.
abstract: Granulocyte colony-stimulating factor (G-CSF) is a cytokine critical for proliferation and differentiation of granulocytic precursors and neutrophil functions that has previously been demonstrated to activate Stat3 and Stat5, two members of the signal transducer and activator of transcription (STAT) protein family. Stat3 has been identified to be critical for G-CSF receptor (G-CSFR)-mediated signaling for granulocyte differentiation. Stat5 activation has been mapped to the proximal portion of the cytosolic region of the G-CSFR. However, delineation and mapping of the specific Stat5 isoforms activated by G-CSF in myeloid cells have not been reported. In this study, we demonstrated that G-CSF activated a Stat5 complex in human myeloid cells containing three isoforms of Stat5: Stat5A, Stat5B, and Stat5 p80. Activation of Stat5A and Stat5B maps to the proliferation-specific domain of the G-CSFR, whereas Stat5 p80 is recruited by phosphotyrosine-704 within the region of G-CSFR required for differentiation. G-CSF-activated Stat5A/B, but not Stat5 p80, formed a heterodimer with Stat3. The Stat5A/B-Stat3 heterodimer can bind to specific DNA sequences preferred by both Stat3 and Stat5. These findings are consistent with the possibility that Stat5 p80 contributes to G-CSF-induced myeloid differentiation.
authors.affiliation: Section of Infectious Diseases, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: A
authors.initials: A
authors.lastname: Chakraborty
authors.forename: K F
authors.initials: KF
authors.lastname: Dyer
authors.forename: D J
authors.initials: DJ
authors.lastname: Tweardy
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D008894:Milk Proteins; D022423:Myeloid Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019000:Phosphotyrosine / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D020033:Protein Isoforms / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism; D050799:STAT5 Transcription Factor; D015534:Trans-Activators / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D020298:U937 Cells
chemical_list: D004268:DNA-Binding Proteins; D008894:Milk Proteins; D020033:Protein Isoforms; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; C494095:STAT5B protein, human; D015534:Trans-Activators; D025521:Tumor Suppressor Proteins; D016179:Granulocyte Colony-Stimulating Factor; D019000:Phosphotyrosine; D004247:DNA