LRRK2 regulates AP2M1 phosphorylation cycles to mediate endocytosis and dopaminergic neurodegeneration

Abstract

Recent genetic evidence revealed endocytic pathway plays a major role in Parkinsons disease (PD). However, the molecular mechanism is poorly understood. Here we report that LRRK2, the most genetic cause of PD, binds to and phosphorylates AP2M1, the core component of endocytosis recently implicated in PD risk. Both knockout and overexpression of LRRK2 cause abnormal AP2M1 phosphorylation cycle and in turn endocytic defects. Mechanistically, knockout of LRRK2 decreases AP2M1 phosphorylation required for the initial clathrin coated vesicle (CCV) formation while LRRK2 overexpression inhibits AP2M1 uncoating for entering into a new cycle of CCV formation. Our study also uncovered a novel tissue-specific regulation of AP2M1 phosphorylation by LRRK2. Further, we found LRRK2 phosphorylation on AP2M1 mediates LRRK2-induced neuronal toxicity both in vitro and in vivo. Importantly, AP2M1 phosphorylation levels are elevated in PD patient fibroblasts. Together, our study provides a direct mechanistic link between LRRK2, AP2 and endocytosis in PD pathogenesis.