Data analysis using a single-binding-site model gave a Kd of 344 ± 74 nM and 356 ± 72 for [3H]-AZ8838 antagonist to wild-type and StaR, respectively. High-affinity binding of agonist [3H]-acetyl-GB110 was observed to wild-type PAR2 with a Kd of 34 ± 5 nM, whereas no binding could be detected to PAR2-StaR, indicative of an antagonist-stabilized state. Data were fitted to a single-binding-site model and the reported values are the mean ± s.e.m. of two independent experiments, except in b, which is based on three experiments. Error bars represent s.e.m.