Distinct cytoplasmic regions of the human granulocyte colony-stimulating factor receptor involved in induction of proliferation and maturation.

Abstract

The granulocyte colony-stimulating factor receptor (G-CSF-R) transduces signals important for the proliferation and maturation of myeloid progenitor cells. To identify functionally important regions in the cytoplasmic domain of the G-CSF-R, we compared the actions of the wild-type receptor, two mutants, and a natural splice variant in transfectants of the mouse pro-B cell line BAF3 and two myeloid cell lines, 32D and L-GM. A region of 55 amino acids adjacent to the transmembrane domain was found to be sufficient for generating a growth signal. The immediate downstream sequence of 30 amino acids substantially enhanced the growth signaling in the three cell lines. In contrast, the carboxy-terminal part of 98 amino acids strongly inhibited growth signaling in the two myeloid cell lines but not in BAF3 cells. Truncation of this region lead to an inability of the G-CSF-R to transduce maturation signals in L-GM cells. An alternative carboxy tail present in a splice variant of the G-CSF-R also inhibited growth signaling, notably in both the myeloid cells and BAF3 cells, but appeared not to be involved in maturation.

Chronic neutrophilic leukemia 2016: Update on diagnosis, molecular genetics, prognosis, and management

“…An unexpectedly high frequency of mutations in the CSF3R were found in 59% (16 of 27) patients with CNL and aCML, compared to only 1% of patients with AML (n 5 292). Two types of mutations were found; most were in the membrane proximal region which mediates proliferative and survival signals: CSF3R T618I (n 5 12) and CSF3R T615A (n 5 2) [1,9,10]. These occurred alone or in association with nonsense mutations that truncate cytoplasmic tail (a region important in transduction of maturation and suppression of proliferation) [1,9,10].…”

STAT3-mediated differentiation and survival of myeloid cells in response to granulocyte colony-stimulating factor: role for the cyclin-dependent kinase inhibitor p27Kip1

“…Jaks associate with the membrane-proximal cytoplasmic region of the receptors and become activated upon ligand binding (Dong et al, 1995;Quelle et al, 1994).…”

“…Whereas the membrane-proximal cytoplasmic region of the G-CSF-R is su cient for activation of STAT1 and STAT5, activation of STAT3 requires the membranedistal C-terminal part of the receptor (de Koning et al, 1996a;Tian et al, 1996). The G-CSF-R C-terminus contains four conserved tyrosine residues (Y704, Y729, Y744, and Y764) and comprises a region that has speci®cally been implicated in the control of neutrophilic di erentiation (Dong et al, 1993;Fukunaga et al, 1993). We and others have recently reported that Y704 and Y744 are involved in recruitment and activation of STAT3 (Chakraborty et al, 1999;de Koning et al, 1996a;Ward et al, 1999a).…”

The gene encoding the granulocyte colony-stimulating factor receptor is a target for deregulation in pre-B ALL by the t(1;19)-specific oncoprotein E2A-Pbx1

“…When these cells are stably transfected with G-CSFr, they can survive and proliferate on G-CSF instead of IL-3. Removal of the carboxy terminal domain of G-CSFr, responsible for myeloid di erentiation, has no in¯uence on the proliferative capacity of these cells, indicating that this signaling domain is only functional in the context of a myeloid cell (Dong et al, 1993). Furthermore, G-CSFr has been implicated in carcinogenesis.…”

“…The blot was hybridized using a 32 Plabeled probe derived from the G-CSFr fragments from round 3 from RDA #1 ( Table 1). The blot was exposed for 48 h and hybridizing material was visualized using a Molecular Dynamics phosphorimager As a control for the speci®city of the LMM741 antibody, we included (myeloid) 32D cells, which do not express G-CSFr, and 32D cells stably transfected with human G-CSFr (Dong et al, 1993). These results indicate that LMM741 only recognizes a surface antigen (G-CSFr) present on the G-CSFr-transfected 32D cells, and does not crossreact with other antigens on wt 32D cells (Figure 4a, left upper and lower panel).…”