Granulocyte colony-stimulating factor receptor mediated cell growth and differentiation

Granulocyte colony-stimulating factor (G-CSF) can elicit different biological responses through interaction with its receptor (G-CSFR). A series of G-CSFR expressing clones were established from WEHI-3B D+ myelomonocytic leukemia cells and interleukin-3 (IL-3) dependent Ba/F3 preB cells by transduction of a G-CSFR cDNA. The overexpression of the G-CSFR from the expression vector promoted differentiation in WEHI-3B D+ cells exposed to G-CSF, while, in contrast, the cytokine supported growth in Ba/F3 cells transfected with the expression plasmid in the absence of IL-3. Western blotting, immunoprecipitation and cell surface labeling with Na[125I] followed by immunoprecipitation with an anti-G-CSFR antibody revealed different patterns of detected proteins in these two cell lines, implying that different forms of the G-CSFR were generated which produced distinct biological responses and/or that different cell-type specific signal transducers were involved in the production of cellular differentiation or growth.