Abstract
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, G(i) and G(s), 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 GTPγS attenuated the specific binding of [3H]PAF, suggesting the occurrence of coupling between pertussis toxin-sensitive G(i) protein and PAF receptors in eosinophils and neutrophils.