19). Dopaminergic cell loss, characteristic of PD, can be mimicked in vivo by exposure to toxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (20, 21) or rotenone, which inhibit Complex I of the mitochondrial respiratory chain (22, 23). LRRK2 has been linked to protection from mitochondrial stress through interaction with kinases of the mitogen-activated protein kinase family (24), whereas recent studies suggest that G2019S LRRK2 causes uncoupling of mitochondrial oxidative phosphorylation (25, 26). Here, LRRK2 is linked to Parkinson disease.