Figure 6. CXCR1 and mutants coupled to Gα_i.

(A) COS-7 cells were cotransfected with equal amounts of cDNA (0.1 µg per well per component) encoding Gα_i2, Gβ₁, Gγ₂, PLCβ₂, the WT CXCR1 or its mutants. (B) COS-7 cells were cotransfected with equal amounts of encoding Gα_qi5 (qi5) and the WT CXCR1 or its mutants. The release of inositol phosphates, induced by 40 nM IL-8, was measured 1 hour after the treatment in the presence or absence of pertussis toxin (PTX) (100 ng/ml) for 18 hrs. Data are mean ± SEM of replicate wells from a representative experiment. **, P<0.01, vs. WT+ qi5 (in the absence of IL-8).