UNIPROT:P04141 - FACTA Search

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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)

Granulocyte-macrophage colony-stimulating factor (GM-CSF) provokes a proliferative response and induction of early-response genes such as c-fos in target cells. It also induces rapid tyrosine phosphorylation of cellular proteins, including the beta subunit (betac) of its functional receptor. However, locations and functions of phosphorylated tyrosine residues within the betac are unclear. To elucidate the mechanism of the human GM-CSF receptor signal transduction, mutational analyses were made of the cytoplasmic domain of the beta-c, using murine BA/F3 cells. Deletion of the conserved box 1 motif resulted in loss of tyrosine phosphorylation of the betac, thereby indicating an essential role for this motif in activating the tyrosine kinase which phosphorylates betac. A C-terminal truncated mutant at position 589 activated the c-fos promoter, and this activation was diminished by a substitution at tyrosine 577 (Tyr577). However, the same substitution in the full-length betac did not completely abrogate the c-fos promoter activation, hence, redundant signaling pathways probably exist. When we analyzed signaling molecules functioning downstream of the beta-c we found that Tyr577 is essential for Shc phosphorylation, while tyrosine phosphorylation of PTP1D was mediated through Tyr577 as well as through other site(s). We suggest that GM-CSF stimulates at least two modes of signals leading to Ras activation, an event which ultimately gives rise to promoter activation of c-fos.
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PMID:Granulocyte-macrophage colony-stimulating factor provokes RAS activation and transcription of c-fos through different modes of signaling. 863 92

Interleukin-3 (IL-3) or granulocyte-macrophage colony-stimulating factor (GM-CSF) is known to activate JAK2 in various cells, but the role of JAK2 in IL-3 or GM-CSF receptor signal transduction is largely unknown. We have now examined the role of JAK2 in GM-CSF-induced signaling events in BA/F3 cells. In BA/F3 cells expressing hGMR, activation of JAK2 by hGM-CSF requires the box1 region of hGMR beta. Dominant negative JAK2 (delta JAK2), which lacked the kinase domain suppressed mIL-3 or hGM-CSF-induced c-fos promoter activation as well as c-myc promoter activation/cell proliferation, thereby suggesting that JAK2 is involved in the signaling of both pathways. Further analyses of the role of JAK2 in c-fos gene activation in BA/F3 cells expressing hGMR revealed that delta JAK2 inhibited hGM-CSF-induced phosphorylation of Shc and protein tyrosine phosphatase 1D. Within hGMR beta, the several tyrosine residues which exist are related to activation of Shc or protein tyrosine phosphate 1D, and are phosphorylated in response to hGM-CSF stimulation. In addition, we observed that delta JAK2 inhibited hGM-CSF-induced phosphorylation of hGMR beta. Taken together, our results suggest that JAK2 activated by the box1 region of hGMR mediates hGM-CSF-induced c-fos promoter activation through phosphorylation of hGMR.
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PMID:JAK2 is essential for activation of c-fos and c-myc promoters and cell proliferation through the human granulocyte-macrophage colony-stimulating factor receptor in BA/F3 cells. 864 82

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor that has been shown to support call proliferation in murine fibroblasts engineered to stably express both chains of the human GM-CSF receptor (NIH-GMR). Because the proto-oncogene c-fos is believed to provide a link between short-term signals elicited at the membrane and long-term cellular response, we chose to study the mechanism of GM-CSF-dependent cell regulation using c-fos promoter activity as a molecular marker in both NIH-GMR transfectants and in the CD34+ cell line TF-1. The importance of c-fos and related AP-1 activity in GM-CSF signalling was suggested by a tight correlation between GM-CSF-dependent activation of the c-fos promoter and cell proliferation and by the inhibitory effect of a trans-dominant c-fos mutant on cell growth. To evaluate the contribution of the serum response factor (SRF) associated with the ternary complex factor (TCF) and of STAT proteins to c-fos promoter activation in response to GM-CSF, the SRF binding site (SRE) and/or the STAT binding site (SIE) were inactivated. In serum-free medium, both SRE and SIE are essential to c-fos promoter activation by GM-CSF in NIH-GMR transfectants and in TF-1 cells. No response to GM-CSF was observed when both sites were mutated. The nature of the STAT family member was further investigated by Wester blots and DNA retardation assays using an SIE probe. Our data indicate that GM-CSF induced DNA binding of both STAT1 and STAT3 in NIH-GMR and mainly of STAT3 in TF-1 cells. STAT5 tyrosine phosphorylation was also observed in TF-1 cells. Finally, expression of a dominant negative MAPK mutant, ERK192A, resulted in a decrease of both SRE- and SIE-dependent activation of c-fos promoter by GM-CSF, suggesting that STAT1/3 are regulated not only by tyrosine kinases, but also partially by MAPK.
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PMID:Contribution of both STAT and SRF/TCF to c-fos promoter activation by granulocyte-macrophage colony-stimulating factor. 887 87

Endothelial cells (EC) play a key role in the inflammatory response, both by the production of proinflammatory cytokines and by their interaction with leukocytes. Molecular genetic analysis has demonstrated that functional NF-kappa B sites are involved in the transcription of interleukin-6 (IL-6), IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) genes in response to inflammatory mediators. Thus, we have explored the effect of two inhibitors of the NF-kappa B activation, pyrrolidine dithiocarbamate (PDTC) and N-acetylcysteine (NAC), on the production of these cytokines by EC. Both PDTC and NAC inhibited, in a dose-dependent manner, the synthesis of IL-6, IL-8, and GM-CSF induced by tumor necrosis factor (TNF)-alpha or bacterial lipopolysaccharides (LPS) in human umbilical vein endothelial cells (HUVEC). PDTC appeared to prevent IL-6, IL-8, and GM-CSF gene transcription, as it blocked the induction of specific mRNA by TNF-alpha or LPS. The TNF-alpha mediated transcriptional activation of a chloramphenicol acetyltransferase (CAT) plasmid containing three copies of the -72 kappa B binding site from the IL-6 promoter was abrogated by PDTC. According to transfection experiments, electrophoretic mobility shift assays (EMSA) demonstrated that the antioxidant prevented the induction of NF-kappa B DNA-binding activity by TNF-alpha. Under the same conditions, PDTC by itself or in combination with TNF-alpha, enhanced the DNA-binding activity of AP-1, as well as c-fos and c-jun mRNA levels. Altogether, these results indicate that the antioxidant PDTC specifically inhibits the transcription of IL-6, IL-8, and GM-CSF genes through the inhibition of the NF-kappa B activation, while increasing the expression of AP-1. Our data make evident the antiinflammatory and immunoregulatory potential of the pharmacological inhibition of the NF-kappa B activation. In addition, PDTC and related molecules may be a useful tool to explore the expression of genes involved in the inflammatory response.
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PMID:Pyrrolidine dithiocarbamate inhibits the production of interleukin-6, interleukin-8, and granulocyte-macrophage colony-stimulating factor by human endothelial cells in response to inflammatory mediators: modulation of NF-kappa B and AP-1 transcription factors activity. 889 14

The receptors for human interleukin-3 (IL-3) and human granulocyte-macrophage colony-stimulating factor (GM-CSF), hIL-3R, hGM-CSFR, respectively, consists of two subunits, alpha and beta, both of which are members of the cytokine receptor superfamily. Phosphorylation of tyrosine residues in the hGMR beta subunit and several cellular proteins is observed after hGM-CSF stimulation. We analyzed the role of tyrosine residues in the hGMR beta subunit and the nature of tyrosine kinase, JAK2, in hGMR signal transduction using several hGMR beta subunit mutants. In addition to the box1 region, a membrane distal region (a.a. 544-589) of the hGMR beta was required for c-fos activation. Only one tyrosine residue (Tyr577) existed within the region 544 to 589, and substitution of Tyr577 to phenylalanine in GMR beta 589 resulted in loss of c-fos activation. In contrast, the same substitution in a wild type receptor did not affect GM-CSF induced activities such as c-fos messenger RNA (mRNA) induction and proliferation, but the substitution abolished Shc phosphorylation. These results suggest that the activation of Shc is not essential for c-fos activation and several tyrosine residues cooperate for c-fos activation. It is well documented that IL-3 or GM-CSF activate JAK2 in BA/F3 cells. The role of JAK2 in IL-3/GM-CSF functions, however, is largely unknown. We examined the role of JAK2 in GM-CSF induced signaling pathways. Dominant negative JAK2 (delta JAK2) lacking the C-terminus kinase domain suppressed IL-3/GM-CSF induced c-fos activation and c-myc activation and proliferation, suggesting that JAK2 was involved in both signaling pathways. Protein tyrosine phosphatase SHP-2 (also called PTP 1D) and Shc were phosphorylated by IL-3/GM-CSF in BA/F3 cells; however, these phosphorylation events were inhibited by the expression of delta JAK2. Taken together, these results indicate the JAK2 is a primary kinase regulating all the known activities of GM-CSF. JAK2 mediates GM-CSF induced c-fos activation through receptor phosphorylation and Shc/PTP 1D activation.
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PMID:Roles of JAK kinases in human GM-CSF receptor signal transduction. 897 26

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) activates a set of genes such as c-fos, jun, myc, and early growth response gene 1 (egr-1). Studies on BA/F3 cells that express hGM-CSF receptor (hGMR) showed that two different signaling pathways controlled by distinct regions within the beta subunit are involved in activation of c-fos/c-jun genes and in c-myc, respectively. However, the region(s) of the beta subunit responsible for activation of the egr-1 gene and other regulatory genes has not been identified. We describe here how egr-1 promoter is activated by hGMR through two regions of the beta subunit, with these regions being required for activation of the c-fos promoter. Coexpression of dominant negative (dn) Ras (N17ras) or dn JAK2 almost completely suppressed the activation of egr-1 and c-fos promoters. Deletion analysis of egr-1 promoter showed two cis-acting regions responsible for activation by hGM-CSF or mouse interleukin-3 (mIL-3), one between nucleotide positions (nt) -56 and -116, and the other between nt -235 and -480, which contains tandem repeats of the serum response element (SRE) sites. Similar experiments with the c-fos promoter showed that cis-acting regions containing the SRE/AP-1 sites is sufficient for activation by hGM-CSF. Based on these observations, we propose that signaling pathways activating egr-1 and c-fos promoters are controlled by SRE elements, either through the same or overlapping pathways that involve JAK2 and Ras.
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PMID:Characterization of cis-acting sequences and trans-acting signals regulating early growth response 1 and c-fos promoters through the granulocyte-macrophage colony-stimulating factor receptor in BA/F3 cells. 902 42

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) induces various signaling events in hematopoietic cells. We reported that there are at least two distinct pathways of hGM-CSF signals, one for activation of proliferation and the other one for activation of c-fos promoter through the MAPK cascade. Activation of other members of the MAPK family, c-Jun N-terminal kinase (JNK) and p38 MAPK under various cellular stress have also been reported. We found that hGM-CSF activates JNK in BA/F3 cells expressing the hGM-CSF receptor (hGMR) and that activation depends on a membrane proximal region including box1 and requires a more membrane distal region of hGMR beta subunit (beta c). There are 8 known tyrosine (tyr) residues in the cytoplasmic region of beta c. Mutant beta c lacking all the tyr residues hardly activates JNK, thereby indicating that the tyr residue(s) is essential for the activation of JNK. Mutation analyses of each tyr residue indicated that none of the tyr residues seems essential for the activation of JNK, indicating multiple tyr residues play a similar function to transduce signals for this activation.
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PMID:Activation of c-Jun N-terminal kinase by human granulocyte macrophage-colony stimulating factor in BA/F3 cells. 917 61

The Janus kinase (JAK)-signal transducers and activators of transcription (STAT) pathway is an important signaling pathway of interferons and cytokines. We examined the activation of STAT proteins induced by interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), or erythropoietin (EPO) using the human leukemia cell line, UT-7, which requires these cytokines for growth. IL-3, GM-CSF, and EPO induced DNA-binding activity to the oligonucleotides corresponding to the sis-inducible elements (SIE) of c-fos, in addition to the beta-casein promoter (beta-CAP), SIE- and beta-CAP-binding proteins were identical to Stat1alpha and Stat3 complex and to Stat5 protein, respectively. This indicates that IL-3, GM-CSF, and EPO commonly activated Stat1alpha, Stat3, and Stat5 proteins in UT-7. However, EPO hardly activated Stat1alpha and Stat3 in UT-7/GM, which is a subline of UT-7 that grows slightly in response to EPO. Transfection studies revealed that UT-7/GM cells constitutively expressing Stat1alpha, but not Stat3, can grow as well in response to EPO as GM-CSF, suggesting that Stat1alpha is involved in the EPO-induced proliferation of UT-7. Thus, although Stat1alpha, Stat3, and Stat5 proteins are activated by GM-CSF, IL-3, and EPO, our data suggest that each STAT protein has a distinctive role in the actions of cytokines.
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PMID:A distinct function of STAT proteins in erythropoietin signal transduction. 919 60

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces various functions, including the proliferation and differentiation of a broad range of hematopoietic cells. We previously reported that at least two distinct pathways are involved in human GM-CSF receptor signaling; both require the box 1 region of the common beta subunit (beta c). This region is essential for the activation of JAK2, which is necessary for all the biological functions of GM-CSF. The activation of JAK2 by GM-CSF leads to rapid tyrosine phosphorylation of cellular proteins, including the beta c. However, the significance of beta c phosphorylation with regard to the regulation of signaling molecules and the expression of GM-CSF functions is less well understood. Here we investigated the role of the cytoplasmic tyrosine residues of the beta c by using a series of beta c mutants expressed in murine BA/F3 cells. A mutant beta c with all eight cytoplasmic tyrosines converted to phenylalanine (Fall) activated JAK2 but not SHP-2, MAPK cascades, STAT5, or the c-fos promoter in BA/F3 cells, and it did not effectively induce proliferation. Adding back each tyrosine to Fall revealed that Tyr577, Tyr612, and Tyr695 are involved in the activation of SHP-2, MAPK cascades, and c-fos transcription, while every tyrosine, particularly Tyr612, Tyr695, Tyr750, and Tyr806, facilitated STAT5 activation. Impaired growth was also restored, at least partly, by any of the tyrosines. These results provide evidence that beta c tyrosines possess distinct yet overlapping functions in activating multiple signaling pathways induced by GM-CSF.
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PMID:Definition of the role of tyrosine residues of the common beta subunit regulating multiple signaling pathways of granulocyte-macrophage colony-stimulating factor receptor. 944 70

Although transcriptional activation of the c-fos proto-oncogene plays an intrinsic role in the mechanism of blood cell growth, it is still obscure how protein-tyrosine kinases (PTKs) regulate the cytokine-driven c-fos activation pathway. We present here that Tec PTK is tyrosine-phosphorylated and activated by granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation in a human GM-CSF-dependent cell line. Moreover, we could show that introduction of Tec into mouse BA/F3-hGMRalphabeta cells can profoundly activate the c-fos promoter in response to GM-CSF or to interleukin-3 (IL-3). In contrast, introduction of a kinase-deleted Tec could suppress cytokine-driven c-fos activation, indicating that Tec is directly involved in the regulation of c-fos transcription. Interestingly, strong activation by Tec of the c-fos promoter was blocked by the co-expression of dominant negative Jak2. The molecular interaction between Tec and Jak2 was then investigated both in mammalian and insect cell systems, revealing that they can not only bind to each other, but either of the two can phosphorylate the other. Thus, Tec and Jak2 can "cross-talk" in a complexed way to mediate cytokine-driven c-fos activation.
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PMID:Tec and Jak2 kinases cooperate to mediate cytokine-driven activation of c-fos transcription. 947 12

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