Finally, we assessed whether GrK can induce neuronal alterations via PAR-1 in human cells by measuring intracellular Ca2+ released by differentiated SH-SY5Y human neuroblastoma cells treated with purified GrK in the presence or absence of the PAR-1 inhibitor SCH79797 (Fig. 9a–c). Here, GZMK is linked to neuroblastoma.