Binding and signaling by tagged KISS1R. A and C, Binding displacement assay of MYC- (A) and CFP- (C) KISS1R. COS-7 cells expressing untagged or tagged KISS1R were incubated with 125I-kisspeptin alone or in the presence of increasing concentrations (10−10 to 10−6 m) of unlabeled kisspeptin. Results are the mean ± se of triplicate samples from a representative experiment and are shown as percentage of maximal binding (i.e., binding in the absence of unlabeled kisspeptin). Experiments were repeated at least three times with similar results. B and D, Total inositol phosphate production by MYC- (B) or CFP- (D) KISS1R. Cells expressing untagged or tagged KISS1R were stimulated with increasing kisspeptin concentrations (10−10 to 10−7 m) for 2 h at 37 C. Results are the mean ± se of triplicates from a representative experiment. Experiments were repeated at least three times with similar results. Open circles, untagged KISS1R; squares, MYC-KISS1R; triangles, CFP-KISS1R.