PRR-KISS1R exerts a dominant negative effect on the expression of WT-KISS1R. A, Cell surface expression in the absence of triton. B, Total expression in triton-permeabilized cells. C, Ratio of cell surface expression on total expression. HeLa cells were cotransfected with 1.5 μg of WT-HA-KISS1R alone or with 1 or 3 μg of nontagged PRR-KISS1R (black bars), or with 1.5 μg of PRR-HA-KISS1R alone or with 1 or 3 μg of nontagged PRR-KISS1R (gray bars). ELISA was performed as previously described (see Materials and Methods and Figure 3). Data are reported as the mean ± SEM of 3 independent experiments, each performed in triplicates (*, compared with WT-HA-KISS1R expression in the absence of PRR-KISS1R; §, compared with PRR-HA-KISS1R expression alone); *P < .05, ***P < .001, and §§P < .01.