fMet-Leu-Phe (fMLP) stimulated the formation of inositol bis- and trisphosphate in the [3H]inositol-labeled plasma membranes from the human leukemic (HL-60) cells differentiated to neutrophil-like cells by dibutyryl cyclic AMP. The stimulatory effect of fMLP was completely dependent on the simultaneous presence of GTP and Ca2+. The fMLP-stimulated formation of the phosphorylated inositols was markedly reduced by the prior ADP-ribosylation of the membranes with pertussis toxin. This toxin ADP-ribosylated a M(r) ~ 40,000 protein, presumably the α subunit of G(i) and/or G(o), in the membranes. Reconstitution of the membranes ADP-ribosylated by pertussis toxin with G(i) or G(o) purified from rat brain restored the fMLP-stimulated formation of the phosphorylated inositols. The efficiency of the rat brain G(i) and G(o) in this capacity was roughly equal. The rat brain G(i) or G(o) ADP-ribosylated beforehand by pertussis toxin was inactive in this reconstitution. These results indicate that both rat brain G(i) and G(o) have the potency to couple functionally the fMLP receptor to the phospholipase C-mediated polyphosphoinositide hydrolysis and suggest that G(i) or G(o) may be involved in the mechanism of signal transduction from the fMLP receptor to this reaction in the differentiated HL-60 cells.
|Number of pages||5|
|Journal||Journal of Biological Chemistry|
|Publication status||Published - 1986|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology