PAF receptors and G-proteins in human blood eosinophils and neutrophils.

Identification of G-proteins and coupling of PAF receptors to G-proteins have been examined in the membranes of human blood eosinophils and neutrophils. Heterotrimeric G-proteins, Gi and GS, were present in both cell types, as demonstrated by immunoblotting and ADP-ribosylation with pertussis toxin. In addition, a group of low molecular mass (18-28 kDa) monomeric G-proteins was also identified. Pertussis toxin and GTP gamma S attenuated the specific binding of [3H]PAF, suggesting the occurrence of coupling between pertussis toxin-sensitive Gi protein and PAF receptors in eosinophils and neutrophils.