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Query: UNIPROT:P04141 (granulocyte-macrophage colony-stimulating factor)
6,790 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The high-affinity receptors for human granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 are heterodimeric complexes consisting of cytokine-specific alpha subunits and a common signal-transducing beta subunit (hbetac). We have previously demonstrated the oncogenic potential of this group of receptors by identifying constitutively activating point mutations in the extracellular and transmembrane domains of hbetac. We report here a comprehensive screen of the entire hbetac molecule that has led to the identification of additional constitutive point mutations by virtue of their ability to confer factor independence on murine FDC-P1 cells. These mutations were clustered exclusively in a central region of hbetac that encompasses the extracellular membrane-proximal domain, transmembrane domain, and membrane-proximal region of the cytoplasmic domain. Interestingly, most hbetac mutants exhibited cell type-specific constitutive activity, with only two transmembrane domain mutants able to confer factor independence on both murine FDC-P1 and BAF-B03 cells. Examination of the biochemical properties of these mutants in FDC-P1 cells indicated that MAP kinase (ERK1/2), STAT, and JAK2 signaling molecules were constitutively activated. In contrast, only some of the mutant beta subunits were constitutively tyrosine phosphorylated. Taken together, these results highlight key regions involved in hbetac activation, dissociate hbetac tyrosine phosphorylation from MAP kinase and STAT activation, and suggest the involvement of distinct mechanisms by which proliferative signals can be generated by hbetac.
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PMID:Saturation mutagenesis of the beta subunit of the human granulocyte-macrophage colony-stimulating factor receptor shows clustering of constitutive mutations, activation of ERK MAP kinase and STAT pathways, and differential beta subunit tyrosine phosphorylation. 973 Oct 57

The signal transduction pathways activated by tumor necrosis factor alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) that lead to priming of polymorphonuclear leukocytes (PMNs) are unknown. The hypotheses that these cytokines stimulate multiple mitogen-activated protein kinase (MAPK) cascades, including extracellular signal-regulated kinases (ERKs), c-Jun amino-terminal kinases (JNKs), and p38 MAPK, and that these MAPKs participate in priming of human PMNs were examined. TNF-alpha stimulated a dose-dependent increase in ERK and p38 MAPK activities that was maximal at 10 min. JNKs were not stimulated by TNF-alpha or GM-CSF. GM-CSF stimulated ERK activity comparable to that of TNF-alpha, but GM-CSF was a less potent stimulus of p38 MAPK activity. The tyrosine kinase inhibitor, genistein, inhibited ERK and p38 MAPK stimulation by both cytokines. The phosphatidylinositol 3-kinase inhibitor, wortmannin, attenuated stimulation of ERKs and p38 MAPK by GM-CSF, but not TNF-alpha. GM-CSF, but not TNF-alpha, stimulated wortmannin-sensitive activation of Raf-1. TNF-alpha and GM-CSF priming of superoxide release stimulated by N-formyl-methionyl-leucyl-phenylalanine was significantly attenuated by the MEK inhibitor, PD098059, and the p38 MAPK inhibitor, SB203580. Incubation with both MAPK inhibitors produced an additive effect. Our data suggest that TNF-alpha and GM-CSF activate ERKs and p38 MAPK by different signal transduction pathways. Both ERK and p38 MAPK cascades contribute to the ability of TNF-alpha and GM-CSF to prime the respiratory burst response in human PMNs.
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PMID:Activation of mitogen-activated protein kinase cascades during priming of human neutrophils by TNF-alpha and GM-CSF. 976 35

To clarify the differences of the signaling pathways used by granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor- (TNF), we investigated activation of mitogen-activated protein kinase (MAPK) subtype cascades in human neutrophils stimulated by these cytokines. G-CSF exclusively tyrosine-phosphorylated extracellular signal-regulated kinase (ERK). GM-CSF tyrosine-phosphorylated ERK strongly and p38 MAPK weakly, whereas TNF tyrosine-phosphorylated p38 MAPK strongly and ERK weakly. Consistent with these findings, MEK, an upstream kinase of ERK, was phosphorylated by G-CSF, GM-CSF, and TNF, whereas MKK3/MKK6, an upstream kinase of p38 MAPK, was phosphorylated by GM-CSF and TNF, but not by G-CSF. The potency of these cytokines to phosphorylate ERK and MEK was GM-CSF > G-CSF > TNF, whereas that to phosphorylate p38 MAPK and MKK3/MKK6 was TNF > GM-CSF. C-Jun amino-terminal kinase (JNK) was not tyrosine-phosphorylated by any cytokine despite the existence of JNK proteins in human neutrophils, whereas it was tyrosine-phosphorylated by TNF in undifferentiated and all-trans retinoic acid-differentiated HL-60 cells. Increased phosphorylation of ERK or p38 MAPK was detected within 1 to 5 minutes after stimulation with each cytokine and was dependent on the concentrations of cytokines used. MEK inhibitor (PD98059) reduced tyrosine phosphorylation of ERK, but not p38 MAPK, induced by G-CSF, GM-CSF, or TNF. GM-CSF- or TNF-induced superoxide (O2-) release was inhibited by p38 MAPK inhibitor (SB203580) in a dose-dependent manner, suggesting the possible involvement of p38 MAPK in GM-CSF- or TNF-induced O2- release. The results indicate that G-CSF, GM-CSF, and TNF activate the overlapping but distinct MAPK subtype cascades in human neutrophils and suggest that the differential activation of ERK and p38 MAPK cascades may explain the differences of the effects of these cytokines on human neutrophil functions.
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PMID:Cytokine-specific activation of distinct mitogen-activated protein kinase subtype cascades in human neutrophils stimulated by granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha. 986 79

Incubation of human neutrophils with a chemotactic peptide [N-formylmethionyl-leucylphenylalanine (fMLP)] gave rise to an increase in the phosphoinositide 3-kinase (PI3K) activity, phosphorylation of p47phox and superoxide-anion (O2(-)) generation in the same fMLP-concentration-dependent manner. These responses to fMLP were markedly enhanced when the cells had been incubated for 10 min before the addition of fMLP with increasing concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF) that were only slightly effective themselves. Wortmannin, an inhibitor of PI3K, suppressed all of these fMLP actions in the same concentration-dependent manner in either GM-CSF-primed or non-primed cells. Sustained activation of protein kinase C by the addition of PMA caused marked phosphorylation of p47phox and respiratory burst itself without activation of PI3K. This strong action of PMA was not primed by GM-CSF. The chemotactic peptide was without effect in pertussis-toxin-treated cells, indicating that its actions are mediated by betagamma-subunits liberated from toxin-susceptible heterotrimeric Gi proteins (Gbetagamma). Thus one of the mechanisms of GM-CSF-mediated priming of fMLP-induced respiratory burst is synergistic activation of wortmannin-sensitive PI3K by Gbetagamma in the presence of tyrosine-phosphorylated proteins in GM-CSF-treated cells, as recently indicated in a cell-free system [Kurosu, Maehama, Okada, Yamamoto, Hoshino, Fukui, Ui, Hazeki and Katada (1997) J. Biol. Chem. 272, 24252-24256]. GM-CSF primed fMLP-induced MAP (mitogen-activated protein) kinase activation enormously as well. The MAP kinase activation was primed even in the presence of wortmannin, indicating that PI3K was not the sole site where tyrosine kinase-related and Gbetagamma-mediated intracellular signals converge to elicit the priming. The GM-CSF priming of fMLP-induced PI3K activation and O2(-) generation was much smaller in magnitude in neutrophils in which cAMP accumulated upon incubation with prostaglandin E1 than in the cells without the nucleotide accumulation. Thus the GM-CSF priming site, in addition to PI3K, might be just the target of cAMP-dependent protein kinase A in fMLP-initiated signalling cascades or could be localized immediately downstream thereof.
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PMID:Enhancement of chemotactic peptide-induced activation of phosphoinositide 3-kinase by granulocyte-macrophage colony-stimulating factor and its relation to the cytokine-mediated priming of neutrophil superoxide-anion production. 988 16

The Janus tyrosine kinase 2 (JAK2) plays an essential role of cytokine receptor signaling, including that of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor. We reported earlier that the activation of JAK2 is essential for all the examined signals induced by human GM-CSF through the box1 region of betac, such as promotion of cell survival and proliferation. To elucidate the role of JAK2 in cell survival and proliferation, we generated an artificial activation system by constructing a chimeric molecule (beta/JAK2) consisting of betac extracellular and transmembrane regions fused with JAK2, and we analyzed various signaling events in interleukin-3-dependent mouse pro-B cell, BA/F3. The beta/JAK2 was constitutively phosphorylated in the absence of human GM-CSF and murine interleukin-3, and this led to proliferation and cell survival. Western blot analysis showed that STAT5, Shc, and SHP-2 were not phosphorylated in the cells, and the consistent activation of beta-casein and c-fos promoters was not enhanced. In contrast, c-myc transcription was constitutively activated. We propose that the activation of beta/JAK2 suffices for survival and proliferation and that the activation of STAT5 and mitogen-activated protein kinase cascade is not required for these activities in BA/F3 cells.
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PMID:Constitutive activation of JAK2 confers murine interleukin-3-independent survival and proliferation of BA/F3 cells. 1003 24

Hematopoietic cells require cytokine-initiated signals for survival as well as proliferation. The pathways that transduce these signals, ensuring timely regulation of cell fate genes, remain largely undefined. The NFIL3 (E4BP4) transcription factor, Bcl-xL, and constitutively active mutants of components in Ras signal transduction pathways have been identified as key regulation proteins affecting murine interleukin-3 (IL-3)-dependent cell survival. Here we show that expression of NFIL3 is regulated by oncogenic Ras mutants through both the Raf-mitogen-activated protein kinase and phosphatidylinositol 3-kinase pathways. NFIL3 inhibits apoptosis without affecting Bcl-xL expression. By contrast, Bcl-xL levels are regulated through the membrane proximal portion in the cytoplasmic domain of the receptor (betac chain), which is shared by IL-3 and granulocyte-macrophage colony-stimulating factor. Activation of either pathway alone is insufficient to ensure cell survival, indicating that multiple independent signal transduction pathways mediate the survival of developing B-lymphoid cells.
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PMID:Two distinct interleukin-3-mediated signal pathways, Ras-NFIL3 (E4BP4) and Bcl-xL, regulate the survival of murine pro-B lymphocytes. 1008 41

Granulocyte-macrophage colony-stimulating factor (GM-CSF) transmits anti-apoptotic signals in eosinophils and is involved in tissue eosinophilia at the site of allergic inflammation. We determined whether phosphatidylinositol 3-kinase (PI 3-kinase) and mitogen-activated protein kinase (MAP kinase) are involved in anti-apoptotic signals of GM-CSF in eosinophils. GM-CSF phosphorylated Akt, a downstream component of PI 3-kinase, and MAP kinases (ERK1 and ERK2) at 10 min after stimulation in eosinophils. GM-CSF prevented eosinophil apoptosis and sustained its survival during the 5-day culture. However, neither two PI-3 kinase inhibitors, wortmannin and LY294002, nor MEK inhibitor PD98059 inhibited GM-CSF-induced survival of eosinophils, although wortmannin and PD98059 inhibited GM-CSF-induced Akt phosphorylation and MAP kinase activation in eosinophils, respectively. In contrast, JAK2 inhibitor AG-490 inhibited both GM-CSF-induced JAK2 phosphorylation and cell survival in eosinophils. These results indicate that activation of JAK2, but not activation of PI 3-kinase/Akt and MAP kinase pathways, is critical for anti-apoptotic signals of GM-CSF in human eosinophils. Our findings suggest that manipulation of JAK2 activation would be useful for the treatment of allergic disorders.
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PMID:Involvement of JAK2, but not PI 3-kinase/Akt and MAP kinase pathways, in anti-apoptotic signals of GM-CSF in human eosinophils. 1033 1

The role of granulocyte colony-stimulating factor (G-CSF) on neutrophilic differentiation of Me2SO-treated HL-60 cells was studied. G-CSF augmented the functional maturation of Me2SO-treated HL-60 cells in terms of both O-2-generating ability and expression of the formyl-methionyl-leucyl-phenylalanine receptor. G-CSF induced enhancement of cell growth in Me2SO-treated HL-60 cells. These results indicate that G-CSF is a potent enhancer for the differentiation and proliferation of Me2SO-treated HL-60 cells. G-CSF caused the activation of p70 S6 kinase but not mitogen-activated protein (MAP) kinase. On the other hand, G-CSF rapidly induced tyrosine phosphorylation of signal transducers and activators of transcription-3 (STAT3), but did not induce serine727 phosphorylation. From the analysis of confocal laser scanning fluorescence microscopy and differential centrifugation, it was clearly demonstrated that G-CSF induced nuclear translocation of tyrosine-phosphorylated STAT3. The G-CSF-dependent enhancement of neutrophilic differentiation in Me2SO-HL-60 cells was reversely inhibited by granulocyte-macrophage colony-stimulating factor (GM-CSF). Notably, in the presence of GM-CSF, G-CSF induced the tyrosine phosphorylation of STAT3 but failed to induce the nuclear translocation of tyrosine-phosphorylated STAT3. GM-CSF induced activation of not only p70 S6 kinase, but also of MAP kinase. Furthermore, GM-CSF caused the rapid serine727 phosphorylation of STAT3, both in the presence and absence of G-CSF. PD98059, an MEK1 inhibitor, inhibited the G-CSF-dependent serine727 phosphorylation of STAT3 and blocked the inhibitory effect of GM-CSF on G-CSF-dependent nuclear translocation of STAT3. These results suggest that G-CSF-dependent nuclear translocation of STAT3 coordinates with the promotion of neutrophilic differentiation in Me2SO-treated HL-60 cells.
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PMID:The role of STAT3 in granulocyte colony-stimulating factor-induced enhancement of neutrophilic differentiation of Me2SO-treated HL-60 cells. GM-CSF inhibits the nuclear translocation of tyrosine-phosphorylated STAT3. 1033 53

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL) -3 induced tyrosine phosphorylation of 92-kDa protein in normal human monocytes. We identified this 92-kDa protein as STAT5, but not as STATs1, 3, and 6 nor c-fes and vav protooncogene products, and demonstrated its translocation to the nucleus, enhancement of specific DNA binding capacity, and potentiation of trancriptional activity by GM-CSF. N-formyl-methionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA) induced tyrosine phosphorylation of 42- and 44-kDa proteins, which were identified as extracellular signal-regulated kinase (ERK), in human monocytes. In marked contrast to neutrophils and MO7e cells, GM-CSF did not induce tyrosine phosphorylation and activation of ERK in monocytes. Among upstream signaling molecules of ERK, Shc was constitutively associated with Grb2 and was not tyrosine-phosphorylated by GM-CSF and FMLP, and Sos1 and c-Raf-1 were not phosphorylated by GM-CSF, IL-3, TNF, and FMLP in monocytes, whereas all these signaling molecules were affected and/or utilized by GM-CSF in MO7e cells. In contrast to neutrophils, p38 was constitutively phosphorylated and agonist-dependent phosphorylation and activation was not detected in human monocytes. Superoxide release stimulated by FMLP was inhibited partially by PD98059 or SB203580, a specific inhibitor of ERK or p38 pathway, and was almost completely inhibited by the combination of both inhibitors, whereas PMA-induced superoxide release was resistant to these two inhibitors in monocytes. PD98059 inhibited GM-CSF-dependent proliferation of MO7e cells. Present results indicate trancriptional roles of STAT5 and functional roles of ERK and/or p38 in normal human monocytes stimulated by physiological receptor-mediated agonists GM-CSF and FMLP. Possible roles of ERK in proliferation of transformed cells were also suggested.
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PMID:Signal transduction pathways in normal human monocytes stimulated by cytokines and mediators: comparative study with normal human neutrophils or transformed cells and the putative roles in functionality and cell biology. 1037 96

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a multifunctional cytokine, having different effects on primitive hemopoietic cells and terminally differentiated end-cells of the myeloid lineage. Human primitive hemopoietic cells (CD34+) were obtained from the peripheral blood after mobilization and induced to proliferate and then differentiate with a combination of cytokines in vitro. Cells at different time points were then used to analyze the expression of the GM-CSF receptor and GM-CSF mediated activation of the JAK 2-STAT 5 and MAP kinase pathways. Scatchard analysis as measured by radioligand binding revealed that freshly purified CD34+ cells expressed 36+/-1 high affinity receptors per cell (mean +/- SE, n = 3) and the level of expression was not significantly different after 3 days in culture, but rose five- to tenfold by day 8. The day 0 CD34+ cells were hyporesponsive to GM-CSF, but by 3 days in culture the cells were still morphologically immature but were actively proliferating and exhibited maximal GM-CSF induced JAK 2-STAT 5 and MAP kinase activation at the optimal time point. Further culture of the CD34+ cells resulted in myeloid differentiation associated with prolongation of MAP kinase activation but not JAK 2-STAT 5 activation. These data indicate that the JAK 2-STAT 5 and MAP kinase pathways are independently regulated and that changes in these signaling pathways occur with differentiation.
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PMID:Changes in signal transduction downstream from the granulocyte-macrophage colony-stimulating factor receptor during differentiation of primary hemopoietic cells. 1037 97


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