Disease relevance of Csf3r

• In approximately 20% of cases of severe congenital neutropenia (SCN), mutations are found in the gene encoding the granulocyte colony-stimulating factor receptor (G-CSF-R) [1].
• SCN patients who develop secondary myelodysplastic syndrome and acute myeloid leukemia almost invariably acquired a GCSFR mutation, suggesting that this genetic alteration represents a key step in leukemogenesis [1].
• In addition, clonal culture of bone marrow cells of the truncated G-CSFR Tg mice showed the hypersensitivity to G-CSF in myeloid progenitors [2].
• To elucidate the function of Cb2 in myeloid leukemia cells, a set of in vitro experiments was carried out using 32D/G-CSF-R (granulocyte colony-stimulating factor receptor) cells transfected with exon-1B/exon-2 Cb2 complementary DNA and a myeloid cell line carrying a virus insertion in Cb2 (ie, NFS 78) [3].
• Using a mouse G-CSF receptor probe, we cloned and sequenced a cDNA for hGCSFR from an HL-60 cDNA library in plasmid and used it to identify 31 additional clones from an HL-60 cDNA library in phage [4].

High impact information on Csf3r

• Murine G-CSF receptor expressed in COS cells could bind G-CSF with an affinity and specificity similar to that of the native receptor expressed by mouse NFS-60 cells [5].
• A 3.7 kb mRNA coding for the G-CSF receptor could be detected in mouse myeloid leukemia NFS-60 and WEHI-3B D+ cells as well as in bone marrow cells [5].
• The amino acid sequence encoded by the cDNAs has demonstrated that murine G-CSF receptor is an 812 amino acid polypeptide (Mr, 90,814) with a single transmembrane domain [5].
• The cytoplasmic domain of the G-CSF receptor shows a significant similarity with parts of the cytoplasmic domain of murine interleukin-4 receptor [5].
• To investigate the role of signal transducer and activator of transcription (STAT) proteins in granulocyte colony-stimulating factor (G-CSF)-regulated biological responses, we generated transgenic mice with a targeted mutation of their G-CSF receptor (termed d715F) that abolishes G-CSF-dependent STAT-3 activation and attenuates STAT-5 activation [6].

Biological context of Csf3r

• Receptor activation and 2 distinct COOH-terminal motifs control G-CSF receptor distribution and internalization kinetics [7].
• Studies in cell lines have established that conserved tyrosines Tyr704, Tyr729, Tyr744, Tyr764 within the cytoplasmic domain of G-CSF receptor (G-CSF-R) contribute significantly to G-CSF-induced proliferation, differentiation, and cell survival [8].
• The binding site for H-ferritin was demonstrated to locate to the box3 motif on the C-terminal region of granulocyte colony-stimulating factor receptor (G-CSFR) [9].
• ROS, acting as a second messenger, might take part in G-CSF receptor signal transduction [9].
• These results indicate a lack of involvement of Jak kinases in signaling by the G-CSFR in neutrophils, and suggest utilization of alternative signal transduction pathways distinct from those in proliferating cells [10].

Anatomical context of Csf3r

• Surprisingly, G-CSFR expression on neutrophils is neither necessary nor sufficient for their mobilization from the bone marrow, suggesting that G-CSF induces neutrophil mobilization indirectly through the generation of trans-acting signals [11].
• This defect was not due to a failure to regenerate HPC following cyclophosphamide administration as the number of CFU-C in the bone marrow of G-CSFR-deficient mice was increased relative to wild-type mice [12].
• We generated mice with an equivalent mutation (gcsfr-triangle Delta715) by homologous and Cre-mediated recombination in embryonic stem cells [13].
• To directly test whether G-CSF can compensate for the myeloid progenitor cell reduction in the T(-) model of hematopoietic deficiency, T(-) and G-CSF-receptor knock-out (GR(-)) mice were crossed, and F1 animals bred to obtain doubly nullizygous mice (T(-)GR(-)) [14].
• Under steady-state conditions the G-CSF-R localized predominantly to the Golgi apparatus, late endosomes, and lysosomes, with only low expression on the plasma membrane, resulting from spontaneous internalization [7].

Associations of Csf3r with chemical compounds

• We generated G-CSF-R-deficient mice and transduced their bone marrow cells with tyrosine "null" mutant (m0), single tyrosine "add-back" mutants, or wild-type (WT) receptors [8].
• In contrast to wild-type mice, no increase in circulating colony-forming cells (CFU-C), CD34+ lineage- progenitors, or day 12 colony-forming unit-spleen progenitors (CFU-S) was detected in G-CSFR-deficient mice after cyclophosphamide administration [12].
• It is interesting that activation of these signaling molecules by G-CSF was prolonged by pretreating cells with actinomycin D or cyclohexamide, suggesting that de novo protein synthesis is required for appropriate termination of G-CSF-R signaling [15].
• The SAG is a chimeric gene encoding the G-CSF receptor (GCR) and the estrogen or tamoxifen (Tm) receptor and is able to expand transduced hematopoietic cells by treatment with estrogen or Tm [16].
• We constructed mutant receptors in which each tyrosine residue of G-CSFR was mutated to phenylalanine [17].

Physical interactions of Csf3r

• Granulocyte colony-stimulating factor (G-CSF) is the major regulator of granulopoiesis and acts through binding to its specific receptor (G-CSF-R) on neutrophilic granulocytes [18].
• To this end, we constructed a chimeric cDNA (GCRER) encoding the fusion protein between the granulocyte colony-stimulating factor receptor (G-CSFR) and the hormone-binding domain (HBD) of the estrogen receptor (ER) as a selective amplifier gene [19].

Enzymatic interactions of Csf3r

• Because a high concentration of G-CSF was observed in the supernatants of leukemic blast cells from these two cases, it seems likely that the soluble G-CSF receptor cut off the autocrine growth mechanism of leukemic blast cells mediated by G-CSF [20].

Regulatory relationships of Csf3r

• The mouse myeloid leukemic cell line (M1) transfected with G-CSF-R cDNA can be induced to differentiate into macrophages in response to G-CSF [21].
• The Mpl-type SAGs induced more potent proliferation of Ba/F3 and cynomolgus CD34(+) cells than the GCR-type SAG [16].
• The ability of tyrosine-to-phenylalanine substitution mutants of the G-CSF receptor to activate STAT3 strongly correlated with their capacity to induce p27 expression and their ability to mediate differentiation and survival, suggesting a causal relationship between STAT3 activation, p27 expression and the observed cellular responses [22].
• Mutation of the most distal tyrosine residue (Tyr763) abolished the ability of G-CSFR to stimulate the tyrosine phosphorylation of a cellular protein with an M(r) of 54 kDa [17].
• G-CSF-induced proliferation, phosphorylation of Stat5, and transcription of Stat5 target genes were increased in HSCs isolated from mice expressing the mutant Csf3r [23].

Other interactions of Csf3r

• Lineage-specific growth factors can compensate for stem and progenitor cell deficiencies at the postprogenitor cell level: an analysis of doubly TPO- and G-CSF receptor-deficient mice [14].
• These results indicated that receptors belonging to different receptor families can be functionally exchanged and confirm that a homodimer of G-CSFR can transduce the growth signal, whereas Fas must be oligomerized (probably trimerized) to transduce the apoptotic signal [24].
• These results show that the G-CSFR is required for mobilization in response to cyclophosphamide or IL-8 but not flt-3 ligand and suggest that the G-CSFR may play an important and previously unexpected role in HPC migration [12].
• In semi-solid medium assays, G-CSFR-infected cells gave rise to all types of colonies [granulocyte-macrophage (GM), megakaryocyte (MK) and mixed lineage (GEMM) colony-forming units (CFU) and erythroid burst-forming units (BFU-E)] in the presence of G-CSF alone [25].
• The role of mutations of the granulocyte colony-stimulating factor receptor (G-CSFR) in the pathogenesis of severe congenital neutropenia (SCN) and the subsequent development of acute myeloid leukemia (AML) is controversial [26].

Analytical, diagnostic and therapeutic context of Csf3r

• Site-directed mutagenesis was used to generate a series of G-CSF receptor (G-CSF-R) mutants in which the tyrosine residues were replaced with phenylalanine either singly or in combination [21].
• Here, the interaction of G-CSFR and H-ferritin was confirmed by yeast two-hybrid screen, mammalian two-hybrid assays, glutathione-S-transferase (GST) pull-down experiments and immunoprecipitation studies in vitro and in vivo [9].
• Overexpression of G-CSFR in transfected clones was demonstrated by northern blotting, binding of [125I]rhG-CSF and cross-linking experiments [27].
• Generation of G-CSF and G-CSF receptor-deficient mice by gene targeting has demonstrated unequivocally the importance of G-CSF in the regulation of baseline granulopoiesis [28].
• Using both a cell surface competitive binding assay and surface plasmon resonance detection of binding kinetics, the MPOs were found to bind to the G-CSF receptor with low nanomolar affinities, similar to that of G-CSF(S17) [29].

References