Binding of G-CSF, GM-CSF, tumor necrosis factor-alpha, and gamma-interferon to cell surface receptors on human myeloid leukemia cells triggers rapid tyrosine and serine phosphorylation of a 75 kd protein

macrophage colony-stimulating factor (GM-CSF),?-inter-feron (?-IFN), or tumor necrosis factor-a (TNF-a) triggered the rapid, stable phosphorylation of a 75-Kd protein ( ~ 7 5) when incubated with permeabilized HL60 human myeloid leukemia cells in the presence of [?-32P] ATP. Among several chemical inducers of HL60 cell differentiation. dimethyl sulfoxide also triggered p75 labeling, but retinoic acid or 12-0-tetradecanoylphorbol-I 3-acetate did not elicit this response. Pretreatment of cells with G-CSF or GM-CSF for more than 30 seconds before permeabilization rendered the p75 labeling undetectable, suggesting that ligand-stimulated labeling was rapidly completed within this time in intact cells. Phosphorylation of p75 occurred on serine and tyrosine residues. This conclusion was con-firmed by direct phosphoamino acid analysis. lmmunoblo