LRRK2 and Parkinson disease: To determine whether the interaction between RCAN1 and Tollip is associated with the progression of PD, we tested the effect of neurotoxin, MPP+, which causes symptoms of PD by destroying dopaminergic neurons in the substantia nigra of the brain, on LRRK2-induced RCAN1-Tollip interaction in neuroblastoma SH-SY5Y cell line.