Gene/Protein Disease Symptom Drug Enzyme Compound
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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 interaction of 125I-labeled recombinant human neutrophil activating factor (NAF) with polymorphonuclear leukocytes (PMN) was studied by means of a radioreceptor assay. The binding was characterized by a rapid transition (t1/2 less than or equal to 1 min) from a pH 3-sensitive state at 4 degrees C to pH 3 resistance at 37 degrees C. This was not caused by internalization of NAF since pH 3-resistant bound iodinated NAF could still be exchanged by an excess of nonlabeled NAF, i.e. was dissociable. Internalized iodinated NAF was processed into trichloroacetic acid-soluble forms. Scatchard transformation of binding isotherms at 4 and 37 degrees C led to nonlinear curves, a finding which is consistent with the expression of two receptor populations, one with high (KD = 11-35 pM) and the other with lower affinity (KD = 640-830 pM) at 4 degrees C. Numbers of the low affinity binding sites were approximately 34,000, and those with high affinity were 5,200/PMN when estimated at 4 degrees C. Binding of iodinated NAF to PMN was specific since it could be competed by an excess of nonlabeled NAF but not by two other activators of PMN function, formylmethionyl-leucyl-phenylalanine or human recombinant granulocyte-macrophage colony-stimulating factor. In addition to human PMN, NAF also bound specifically to two human monocytic cell lines; however, only the low affinity binding site could be detected on these cells.
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PMID:Specific binding, internalization, and degradation of human neutrophil activating factor by human polymorphonuclear leukocytes. 267 6

Radioiodinated granulocyte-macrophage colony-stimulating factor (125I-GM-CSF) binds to specific receptors (molecular weight approximately 50,000 daltons) on the murine myelomonocytic leukemia, WEHI-3BD+. At 4 degrees C 125I-GM-CSF remains on the surface of the cells and can be eluted by washing the cells with acidified isotonic buffer. When the cells are warmed to 37 degrees C, the 125I-GM-CSF is internalized rapidly (t 1/2: 7 min). The internalisation appears to be entirely receptor mediated and is independent of energy sources inhibited by sodium azide. This GM-CSF-mediated internalisation is not due to a general increase in the turnover of cell surface molecules as the specific binding of 125I-transferrin is not affected by incubation of WEHI-3BD+ cells with GM-CSF. The initial 125I released when the cells are warmed to 37 degrees C appears to be intact 125I-GM-CSF; however, after 2 h 80% of the 125I released was not precipitable with trichloroacetic acid and presumably represented degraded 125I-GM-CSF. Ammonium chloride or monensin reduced the release of 125I-GM-CSF from the cells, suggesting that the receptor-bound ligand was processed through the lysosomes. A considerable proportion of the internalised GM-CSF receptors were recycled to the surface and were available for ligand binding. Synthesis of new GM-CSF receptors contributed to the re-expression of GM-CSF receptors after down-regulation and it is possible that the GM-CSF enhances the synthesis of its own receptors.
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PMID:Internalisation and recycling of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor on a murine myelomonocytic leukemia. 354 40

The promoter of the human granulocyte-macrophage colony-stimulating factor gene is regulated by an inducible upstream enhancer. The enhancer encompasses three previously defined binding sites for the transcription factor NFAT (GM170, GM330, and GM550) and a novel NFAT site defined here as the GM420 element. While there was considerable redundancy within the enhancer, the GM330, GM420, and GM550 motifs each functioned efficiently in isolation as enhancer elements and bound NFATp and AP-1 in a highly cooperative fashion. These three NFAT sites closely resembled the distal interleukin-2 NFAT site, and methylation interference assays further defined GGA(N)9TCA as a minimum consensus sequence for this family of NFAT sites. By contrast, the GM170 site, which also had conserved GGA and TCA motifs but in which these motifs were separated by 15 bases, supported strong independent but no cooperative binding of AP-1 and NFATp, and this site functioned poorly as an enhancer element. While both the GM330 and GM420 elements were closely associated with the inducible DNase I-hypersensitive site within the enhancer, the GM420 element was the only NFAT site located within a 160-bp HincII-BalI fragment defined by deletion analysis as the essential core of the enhancer. The GM420 element was unusual, however, in containing a high-affinity NFATp/c-binding sequence (TGGAAAGA) immediately upstream of the sequence TGACATCA which more closely resembled a cyclic AMP response-like element than an AP-1 site. We suggest that the cooperative binding of NFATp/c and AP-1 requires a particular spacing of sites and that their cooperativity and induction via independent pathways ensure very tight regulation of the granulocyte-macrophage colony-stimulating factor enhancer.
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PMID:Human granulocyte-macrophage colony-stimulating factor enhancer function is associated with cooperative interactions between AP-1 and NFATp/c. 789 2