PAR-2 proliferative responses require receptor cleavage. Individual cell lines were incubated with 100 μmol/L PAR-2^39-44, 100 μmol/L TR^42-47, 0.1 U/L tryptase or 1 nmol/L trypsin, and analyzed for proliferative responses at 48 hours. As shown, proliferative responses are abolished using the noncleavable PAR-2 mutant, when activated by either trypsin or β-tryptase. Results represent the mean ± SEM from six wells from a single set of experiments repeated on one occasion.