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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)

Interleukin-5 (IL-5) regulates the production and function of B cells, eosinophils, and basophils. The IL-5 receptor (IL-5R) consists of two distinct membrane proteins, alpha and beta. The alpha chain (IL-5R alpha) is specific to IL-5. The beta chain is the common beta chain (beta c) of receptors for IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cytoplasmic domains of both alpha and beta chains are essential for signal transduction. In this study, we generated cDNAs of IL-5R alpha having various mutations in their cytoplasmic domains and examined the function of these mutants by expressing them in IL-3-dependent FDC-P1 cells. The membrane-proximal proline-rich sequence of the cytoplasmic domain of IL-5R alpha, which is conserved among the alpha chains of IL-5R, IL-3R, and GM-CSF receptor (GM-CSFR), was found to be essential for the IL-5-induced proliferative response, expression of nuclear proto-oncogenes such as c-jun, c-fos, and c-myc, and tyrosine phosphorylation of cellular proteins including JAK2 protein-tyrosine kinase. In addition, analysis using chimeric receptors which consist of the extracellular domain of IL-5R alpha and the cytoplasmic domain of beta c suggested that dimerization of the cytoplasmic domain of beta c may be an important step in activating the IL-5R complex and transducing intracellular growth signals.
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PMID:A critical cytoplasmic domain of the interleukin-5 (IL-5) receptor alpha chain and its function in IL-5-mediated growth signal transduction. 762 58

A full length clone of murine fms-like tyrosine kinase 3 [flt3, also known as fetal liver kinase 2 (flk2)] was constructed from sequences obtained from a brain complementary DNA (cDNA) library and from cDNA prepared from the cell line Tikaut. In the absence of a ligand to study the function of Flt3, a chimeric molecule was constructed comprising the extracellular domain of murine c-Fms and the transmembrane and cytoplasmic domains of Flt3. A plasmid encoding the chimeric receptor was cotransfected along with a plasmid conferring neomycin resistance into FDC-P1 cells that do not normally express c-fms or flt3 and require granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin 3 for growth. Two types of clones were obtained following selection in GM-CSF and G418. Two of seven clones had the capacity for M-CSF-dependent colony formation in semisolid medium, indicating that the cytoplasmic domain of Flt3 can transduce a proliferative signal. From the remaining clones, M-CSF-dependent clonogenic cells could be selected by prior bulk liquid culture in M-CSF. It has been shown previously that the GM-CSF-dependent proliferative capacity is strongly inhibited by M-CSF in FDC-P1 cells engineered to express full length c-fms. This phenomenon was also observed with FD/fms-flt3 cells that were clonogenic in M-CSF. Stimulation of FD/fms or FD/fms-flt3 cells in liquid culture by M-CSF caused differentiation of a small proportion of cells along the myelomonocytic pathway which was enhanced by the combination of M-CSF and GM-CSF.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fms-like tyrosine kinase 3 catalytic domain can transduce a proliferative signal in FDC-P1 cells that is qualitatively similar to the signal delivered by c-Fms. 804 61

The cytokines interleukin-3, interleukin-5, and granulocyte-macrophage colony-stimulating factor bind with high affinity to a receptor complex that contains a ligand-specific alpha-chain and a common beta-chain, h beta c. We report here the isolation of a mutant form of h beta c, from growth factor-independent cells, that arose spontaneously after infection of a murine factor-dependent hematopoietic cell line (FDC-P1) with a retroviral h beta c expression construct. Analysis of this h beta c mutation shows that a small (37 amino acid) duplication of extracellular sequence that includes two conserved sequence motifs is sufficient to confer ligand-independent growth on these cells and lead to tumourigenicity. Because this is a conserved region in the cytokine receptor superfamily, our results suggest that the large family of cytokine receptors has the capacity to become oncogenically active.
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PMID:A mutation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor, and IL-5 that leads to ligand independence and tumorigenicity. 818 Mar 76

cDNA expression cloning is a powerful method for the rescue and identification of genes that are able to confer a readily identifiable phenotype on specific cell types. Retroviral vectors provide several advantages over DNA-mediated gene transfer for the introduction of expression libraries into eukaryotic cells since they can be used to express genes in a wide range of cell types, including those that form important experimental systems such as the hemopoietic system. We describe here a straightforward and efficient method for generating expression libraries by using a murine retroviral vector. Essentially, the method involves the directional cloning of cDNA into the retroviral vector and the generation of pools of stable ecotropic virus producing cells from this DNA. The cells so derived constitute the library, and the virus they yield is used to infect appropriate target cells for subsequent functional screening. We have demonstrated the feasibility of this procedure by constructing several large retroviral libraries (10(5) to 10(6) individual clones) and then using one of these libraries to isolate cDNAs for interleukin-3 and granulocyte-macrophage colony-stimulating factor on the basis of the ability of these factors to confer autonomous growth on the factor-dependent hemopoietic cell line FDC-P1. Moreover, the frequency at which these factor-independent clones were isolated approximated the frequency at which they were represented in the original plasmid library. These results suggest that expression cloning with retroviruses is a practical and efficient procedure and should be a valuable method for the isolation of important regulatory genes.
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PMID:A simple and efficient procedure for generating stable expression libraries by cDNA cloning in a retroviral vector. 828 27

The identification of ras oncogenes in both human and animal tumors as well as in preleukemic and precancerous lesions suggests that activated ras genes participate in neoplastic development, yet the precise role of ras oncogenes in leukemogenesis is not clear. To assess the functional role of ras genes in tumorigenesis, we introduced with a retroviral vector either a wild-type (Gly-12) or a mutant (Val-12) Kirsten ras cDNA into the cells of a factor-dependent myeloid cell line, FDC-P1. FDC-P1 cells are nontumorigenic and their proliferation is dependent on either interleukin-3 (IL-3) or granulocyte-macrophage colony-stimulating factor (GM-CSF). The Ki-Val 12-infected FDC-P1 cell population is still strictly IL-3-dependent but has acquired the ability to survive up to 72 hours in the absence of growth factor and to form tumors in nude mice. These tumors are easily established into cell lines that are clonal and show a multiplicity of phenotypes with respect to their growth factor dependence. These results suggest that, in contrast with the overexpression of a normal Ki-ras, Ki-ras oncogene can efficiently promote the tumorigenic conversion of FDC-P1 cells. However, the clonality of the tumors as well as the distinct phenotypes indicates that other genetic events are required for tumorigenicity. Therefore, in FDC-P1 cells, an activated ras gene acts as a dominant oncogene through the induction of tumor progression. Finally, in this simple experimental system we observed a multiplicity of tumorigenic phenotypes which are reminiscent of those observed in patients with acute myeloid leukemia.
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PMID:Infection with a Kirsten-retrovirus can induce a multiplicity of tumorigenic phenotypes in the interleukin-3-dependent FDC-P1 cells. 829 38

A panel of monoclonal antibodies was raised against the low-affinity human granulocyte-macrophage colony-stimulating factor (hGM-CSF) receptor alpha-chain expressed as recombinant protein on murine FDC-P1 cells. All the selected antibodies were of the IgG2A isotype and bound to protein A. They each recognized both native and recombinant receptors by indirect surface immunofluorescence and by immunoprecipitation. Several of the antibodies also recognized presumably denatured receptors as detected by immunoblotting of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Three different epitopes on the extracellular domain of the GM-CSF receptor alpha-chain were defined by these antibodies, and two of the epitopes did not appear to be involved in binding hGM-CSF or in interactions with the beta-chain of the GM-CSF receptor that are required for high-affinity binding of GM-CSF. On the other hand, the epitope recognized by antibody 2B7-17-A appeared to be critically involved in the binding of GM-CSF because this antibody completely abrogated both high- and low-affinity binding of GM-CSF to native and recombinant receptors. Antibody 2B7-17-A had a relatively high affinity for the GM-CSF receptor alpha-chain (kd = 3 nmol/L) and slow dissociation kinetics (kd = 0.002 min-1). These properties made the 2B7-17-A antibody a potent inhibitor of hGM-CSF biologic action in several different bioassays, with a half-maximal inhibitory dose of about 6 nmol/L (1 microgram/mL). This antibody could prove useful in alleviating any pathologic states mediated by excess GM-CSF levels and in defining the domains of the GM-CSF receptor required for ligand binding.
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PMID:Neutralizing and nonneutralizing monoclonal antibodies to the human granulocyte-macrophage colony-stimulating factor receptor alpha-chain. 840 Feb 29

Injection of 10(6) immortalized, but non-leukemic, granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent FDC-P1 cells into GM-CSF transgenic hybrid mice with elevated GM-CSF levels led to death within three months with elevated blast cell numbers in the blood, massive organ infiltration by blast cells, and associated anemia and thrombocytopenia. No disease developed within this period in littermate mice injected with 10(6) FDC-P1 cells. All moribund transgenic recipients contained transformed FDC-P1 cells able to produce rapidly-growing transplanted leukemias in syngeneic normal DBA/2 recipients. The leukemias appeared to arise in the primary recipients by independent transformation events. The transformed cells from different mice differed in their in vitro growth characteristics, their ability to produce GM-CSF or multipotential CSF, and in the nature of the transplanted tumors derived from the primary cells. While all primary recipients at death contained fully transformed leukemic cells, the bulk of the large population of FDC-P1 cells appeared either to be untransformed or to have altered characteristics not yet representing full transformation. If the FDC-P1 engrafted model has some validity for myelodysplasia, the results suggest that sustained CSF administration to myelodysplastic patients possessing abnormal, potentially preleukemic, granulocyte-macrophage populations may increase the risk of death either from accumulated pretransformed or from fully transformed leukemic cells.
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PMID:Leukemic transformation of immortalized FDC-P1 cells engrafted in GM-CSF transgenic mice. 850 82

Connective tissue cells (myofibroblasts) from liver inflammatory granulomatous reactions to schistosome eggs are able to sustain a long-term proliferation of myeloid cells, both in vivo and in vitro. We have addressed the question of the molecular mechanisms involved in control of this extramedullar stroma-dependent production of inflammatory cells. Heparan sulfate proteoglycans (HSPGs) were purified from granuloma-derived connective tissue cells and bound to plastic or collagen substrate. Their ability to bind recombinant murine granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), to stimulate proliferation of the FDC-P1 myeloid cell lineage, and to modify growth factor activity was monitored. The specificity of this stroma cell-derived glycosaminoglycan interaction with the myeloid growth factors was analyzed by comparing other glycosaminoglycans and sulfated polysaccharides. HSPGs could act as an artificial myelopoietic stroma; they were both required and sufficient for binding and presenting GM-CSF and IL-3 in biologically active form. Moreover, they were able to mediate an increase in the specific growth-promoting activity of GM-CSF and IL-3. This was specific for stroma-derived heparan sulfate and heparin, since heparan sulfate derived from other cells, other glycosaminoglycans and related molecules had no effect. These results indicate that HSPGs can stimulate and control the in situ proliferation of myeloid cells, modifying in both quantitative and qualitative terms the composition of inflammatory cell infiltrates in hepatic granulomas.
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PMID:GM-CSF and IL-3 activities in schistosomal liver granulomas are controlled by stroma-associated heparan sulfate proteoglycans. 860 24

The hypothesis that extracellular truncation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor, and IL-5 (h beta c) can lead to ligand-independent activation was tested by infecting factor-dependent hematopoietic cell lines with retroviruses encoding truncated forms of h beta c. A truncation, resembling that in v-Mpl, and retaining 45 h beta c-derived extracellular residues, led to constitutive activation in the murine myeloid cell line, FDC-P1. However, infection of cells with retrovirus encoding a more severely truncated receptor, retaining only 7 h beta c-derived extracellular residues, did not confer factor independence on these cells. These experiments show that truncation activates the receptor and define a 37-amino acid segment of h beta c (H395-A431) which contains two motifs conserved throughout the cytokine receptor superfamily (consensus Y/H XX R/Q VR and WSXWS), as essential for factor-independent signaling. The mechanism of activation was also investigated in less severe truncations. A receptor that retains the entire membrane-proximal domain (domain 4) also conferred factor independent growth on FDC-P1 cells; however, a retrovirus encoding a truncated form of h beta c having two intact membrane proximal domains did not have this ability, suggesting that domain 3 may have an inhibitory role in h beta c. The ability of these receptors to confer factor independence was cell specific as demonstrated by their inability to confer factor-independent growth when introduced into the murine IL-3-dependent pro-B cell line BaF-B03. These results are consistent with a model in which activation requires unmasking of an interactive receptor surface in domain 4 and association with a myeloid-specific receptor or accessory component. We suggest that in the absence of ligand intramolecular interactions prevent inappropriate signaling.
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PMID:Extracellular truncations of h beta c, the common signaling subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-5, lead to ligand-independent activation. 863 79

Granulocyte-macrophage colony-stimulating factor (GM-CSF) regulates differentiation, survival, and proliferation of colony-forming unit-granulocyte-macrophage progenitor cells. The biologic actions of GM-CSF are mediated by binding to a specific receptor consisting of two chains designated as alpha and beta subunits. We have demonstrated that the murine FDC-P1-derived cell line WT-19 transfected with the human GM-CSF receptor alpha and beta subunits (GM-CSFRalpha and beta) can be induced to differentiate by the addition of human GM-CSF (hGM-CSF). By expressing a series of GM-CSFRalpha mutants in WT19 cells, we have determined the amino acid domains of the GM-CSFRalpha cytoplasmic domain that regulate cell differentiation, proliferation, and survival. We found that the membrane proximal proline-rich domain and adjacent 16 residues are essential for both hGM-CSF-dependent cell proliferation and differentiation. In contrast, the C-terminal region of the GM-CSFRalpha cytoplasmic domain was not necessary for cell differentiation mediated by hGM-CSF, but the removal of this region severely impaired the ability of hGM-CSF to support cell survival. While the activation of JAK2, Shc, Erk, and STAT5 proteins correlated with hGM-CSF-mediated cell growth, cellular differentiation occurred in the absence of activation of these signal transduction pathways.
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PMID:The cytoplasmic domain of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor alpha subunit is essential for both GM-CSF-mediated growth and differentiation. 921 89


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