triacsin-c and 5-oxo-6-8-11-14-eicosatetraenoic-acid

5-Oxo-eicosatetraenoic acid (5-oxoETE) stimulated human neutrophil (PMN) and eosinophil chemotaxis, PMN hexose uptake, and PMN membrane GTP/GDP exchange. Pertussis toxin (PT), a blocker of heterotrimeric G proteins (GP), completely inhibited these responses, but proved far less effective on the same responses when elicited by leukotriene B4, C5a, FMLP, platelet-activating factor, IL-8, or RANTES chemotactic factors. 5-OxoETE also specifically bound to the membrane preparations that conducted GTP/GDP exchange. This binding was down-regulated by GTPgammaS, but not ADPgammaS, and displaced by 5-oxoETE analogues, but not by leukotriene B4, lipoxin A4, or lipoxin B4. Finally, PMN expressed PT-sensitive GP alphaiota2 and PT-resistant GP alphaq/11- and alpha13-chains; eosinophils expressed only alphai2 and alphaq/11. We conclude that 5-oxoETE activates granulocytes through a unique receptor that couples preferentially to PT-sensitive GP. The strict dependency of this putative receptor on PT-sensitive GP may underlie the limited actions of 5-oxoETE, compared with other CF, and help clarify the complex relations between receptors, GP, cell signals, and cell responses.

Topics: Arachidonic Acids; Carbon Radioisotopes; Cell Compartmentation; Cell Membrane; Chemotactic Factors; Deoxyglucose; Eosinophils; GTP-Binding Protein alpha Subunit, Gi2; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gq-G11; GTP-Binding Proteins; Guanosine 5'-O-(3-Thiotriphosphate); Heterotrimeric GTP-Binding Proteins; Humans; Neutrophils; Pertussis Toxin; Proto-Oncogene Proteins; Receptors, Eicosanoid; Solubility; Sulfur Radioisotopes; Triazenes; Virulence Factors, Bordetella