Multiple signals mediate proliferation, differentiation, and survival from the granulocyte colony-stimulating factor receptor in myeloid 32D cells
Granulocyte colony-stimulating factor (G-CSF) regulates neutrophil production through activation of its cognate receptor, the G-CSF-R. Previous studies with deletion mutants have shown that the membrane-proximal cytoplasmic domain of the receptor is sufficient for mitogenic signaling, whereas the membrane-distal domain is required for differentiation signaling. However, the function of the four cytoplasmic tyrosines of the G-CSF-R in the control of proliferation, differentiation, and survival has remained unclear. Here we investigated the role of these tyrosines by expressing a tyrosine "null" mutant and single tyrosine "add back" mutants in maturation-competent myeloid 32D cells. Clones expressing the null mutant showed only minimal proliferation and differentiation, with survival also reduced at low G-CSF concentrations. Analysis of clones expressing the add-back mutants revealed that multiple tyrosines contribute to proliferation, differentiation, and survival signals from the G-CSF-R. Analysis of signaling pathways downstream of these tyrosines suggested a positive role for STAT3 activation in both differentiation and survival signaling, whereas SHP-2, Grb2 and Shc appear important for proliferation signaling. In addition, we show that a tyrosine-independent "differentiation domain" in the membrane-distal region of the G-CSF-R appears necessary but not sufficient for mediating neutrophilic differentiation in these cells.
|Keywords||Animals, Cell Differentiation, Cell Division, Cell Survival, Leukemia, Myeloid/pathology, Mice, Mutation, Receptors, Granulocyte Colony-Stimulating Factor/*physiology, Research Support, Non-U.S. Gov't, Tumor Cells, Cultured|
Ward, A.C., Smith, L., de Koning, J.P., Touw, I.P., & van Aesch, Y.M.. (1999). Multiple signals mediate proliferation, differentiation, and survival from the granulocyte colony-stimulating factor receptor in myeloid 32D cells. Journal of Biological Chemistry. Retrieved from http://hdl.handle.net/1765/9103