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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 human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor is composed of an alpha subunit which binds GM-CSF and a beta subunit which allows for high affinity binding. To investigate the role of the short cytoplasmic tail (54 amino acids) of the alpha receptor in mediating signal transduction and in controlling cell growth, we placed a stop codon after the alpha receptor transmembrane domain and expressed this receptor in murine Ba/F3 cells. Unlike the complete alpha subunit, this shortened receptor was unable to stimulate protein phosphorylation or mediate entry into the cell cycle. By comparing Ba/F3 cells expressing the alpha and beta receptors with those expressing the alpha or the terminated alpha receptor, we have been able to correlate specific GM-CSF-induced events with cell cycle commitment. We find that cell growth is correlated with prolonged increases in the cell levels of c-myc, pim-1, and cyclin D2 mRNAs, but not with changes in either immediate early genes or mitogen-activated protein kinase phosphorylation. This suggests that additional signal transduction pathways not mediated by known phosphoproteins are activated by GM-CSF. Since the beta receptor is shared by human interleukins 3 and 5, our data suggest that the specificity of response to GM-CSF is mediated in part by the short cytoplasmic tail of the alpha receptor subunit.
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PMID:A critical role for the cytoplasmic domain of the granulocyte-macrophage colony-stimulating factor alpha receptor in mediating cell growth. 837 36

The role of positive and negative cytokine interactions in G1 cell cycle regulation of haemopoietic cells was analysed by determination of the expression patterns of D-type cyclins and cyclin-dependent kinases (cdks) in SKM-1 myelodysplastic syndrome (MDS) cells incubated with granulocyte-macrophage colony-stimulating factor (GM-CSF) and/or transforming growth factor-beta 1 (TGF-beta 1). TGF-beta 1 inhibited SKM-1 cell proliferation due to the cell cycle arrest in G1 phase. GM-CSF abrogated the TGF-beta 1-mediated G1 arrest in these cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that TGF-beta 1-mediated G1 arrest correlated with the down-regulation of cdk4, cdk6 and cyclin D2, and that abrogation of TGF-beta 1-mediated G1 arrest by GM-CSF correlated with the constitutive over-expression of cyclin D2 and cdk6 but not cdk4. These results suggest the importance of cyclin D2/cdk6 levels in abrogating G1 arrest in cells exposed to TGF-beta 1, and raise the possibility that the GM-CSF-mediated up-regulatory pathway of signal transduction through cyclin D2/cdk6 differs from the TGF-beta 1-cdk4-mediated pathway in SKM-1 cells. This signal transduction pathway through cyclin D2/cdk6 might play an important role in haemopoietic regulation by the cytokine network.
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PMID:Granulocyte-macrophage colony-stimulating factor abrogates transforming growth factor-beta 1-mediated cell cycle arrest by up-regulating cyclin D2/Cdk6. 933 4

High levels of cytokines are associated with a poor prognosis in acute myeloid leukemia (AML). However, cytokines may induce, on one hand, survival factor expression and cell proliferation and, on the other hand, expression of inhibitory signals such as up-regulation of suppressors of cytokine signaling (SOCS) and induce apoptotic cell death. Because blasts from patients with AML express high procaspase protein levels, we asked whether granulocyte-macrophage colony-stimulating factor (GM-CSF) enhances procaspase protein production in AML cells. In the GM-CSF-responsive OCIM2 AML cell line, GM-CSF induced signal transducer and activator of transcription 5 (Stat 5) phosphorylation, up-regulated cyclin D2, and stimulated cell cycle progression. Concurrently, GM-CSF stimulated expression of SOCS-2 and -3 and of procaspases 2 and 3 and induced caspase 3 activation, poly(ADP[adenosine 5'-diphosphate]-ribose) polymerase (PARP) cleavage, and apoptotic cell death. The Janus kinase (Jak)-Stat inhibitor AG490 abrogated GM-CSF-induced expression of procaspase 3 and activation of caspase 3. Under the same conditions GM-CSF up-regulated production of BAX as well as Bcl-2, Bcl-XL, survivin, and XIAP. GM-CSF also increased procaspase 3 protein levels in OCI/AML3 and Mo7e cells, suggesting that this phenomenon is not restricted to a single leukemia cell line. Our data suggest that GM-CSF exerts a dual effect: it stimulates cell division but contemporaneously up-regulates Jak-Stat-dependent proapoptotic proteins. Up-regulation of procaspase levels in AML is thus a beacon for an ongoing growth-stimulatory signal.
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PMID:Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces antiapoptotic and proapoptotic signals in acute myeloid leukemia. 1266 43