PRKN and Parkinson disease: The parkin protein encoded by PRKN functions as an E3 ubiquitin ligase, and PRKN mutations lead to monogenic PD.226 In dopaminergic neurons, reducing parkin activity induces spontaneous activation of the NLRP3 inflammasomes, and parkin inhibits this activation by ubiquitinating NLRP3.227 These findings suggest that both neuronal and microglial NLRP3 inflammasomes play a role in the pathogenesis of PD; whether the two work synergistically remains to be determined.