The granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor is composed of an α subunit which binds GM-CSF and a β subunit, which together form the high affinity receptor. By transfecting the human α subunit into murine Ba/F3 cells, we have been able to investigate the role of the short 54-amino acid intracytoplasmic portion (amino acid 346-400) of this subunit in mediating cell growth. We have shown that the intracytoplasmic amino acids 346-382 are necessary for GM-CSF-mediated cell growth. In contrast, amino acids 382-400 can be removed without effect. The stable transfection of the human β subunit into the cell lines containing the mutant α subunits did not affect the growth characteristics of these cells. The ability of GM-CSF to stimulate cell growth of the Ba/F3 cells α subunit transfectants was correlated with the ability of this hormone to translocate protein kinase C to the particulate fraction. In contrast, the ability of GM-CSF addition to increase phosphorylation of the human β subunit did not correlate with cell growth and required the entire intracytoplasmic domain of the α subunit. These results demonstrate an important role for the intracytoplasmic portion of the α subunit in mediating both signal transduction and cell cycle commitment stimulated by GM-CSF.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Biological Chemistry|
|State||Published - May 20 1994|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology