RAPID COMMUNICATION Reconstitution of recombinant N-formyl chemotactic peptide receptor with G protein

Abstract: A recombinant human neutrophil N-forinyl peptide receptor (rFPR) expressed in transfected mouse fIbroblasts (TX2 cells) was analyzed for its ability to couple physically with the heterotrimeric C protein, G. Im-munoprecipitation of photoaffinity-labeled rFPR and en-dogenous neutrophil formyl peptide receptor (nFPR) with an anti-FPR peptide antibody demonstrated that the receptors were identical in both size and extent of glycosylation. Coupling of rFPR with endogenous TX2 G was demonstrated by coimmunoprecipitation of the two proteins with an anti-G1 antibody. Moreover, rFPR was able to form a physical complex with purified G1 in a soluble reconstitution system. We observed similar affinities of rFPR and nFPR for G1. This report provides the first direct evidence that rFPR associates physically with G1 and provides a foundation for analysis of the G protein coupling capacity of mutant rFPRs. J. Leukoc