RECONSTITUTION OF RECOMBINANT N-FORMYL CHEMOTACTIC PEPTIDE RECEPTOR WITH G-PROTEIN

A recombinant human neutrophil N-formyl peptide receptor (rFPR) expres sed in transfected mouse fibroblasts (TX2 cells) was analyzed for its ability to couple physically with the heterotrimeric G protein, G(i). Immunoprecipitation of photoaffinity-labeled rFPR and endogenous neutr ophil formyl peptide receptor (nFPR) with an anti-FPR peptide antibody demonstrated that the receptors were identical in both size and exten t of glycosylation. Coupling of rFPR with endogenous TX2 G(i) was demo nstrated by coimmunoprecipitation of the two proteins with an anti-G(i ) antibody. Moreover, rFPR was able to form a physical complex with pu rified G(i) in a soluble reconstitution system. We observed similar af finities of rFPR and nFPR for G(i). This report provides the first dir ect evidence that rFPR associates physically with G(i) and provides a foundation for analysis of the G protein coupling capacity of mutant r FPRs.