Distinctive roles of Rac1 and Rab29 in LRRK2 mediated membrane trafficking and neurite outgrowth

摘要

cqvip:Parkinson's disease(PD) associated leucine-rich repeat kinase 2(LRRK2) mutants have shown pathogenic effects on a variety of subcellular processes. Two small GTPases Rac1 and Rab29 have been indicated as possible downstream effectors participating in LRRK2 signaling but their detail mechanisms remain unclear. In this study, we have used biochemical and cell biology approaches to address whether two GTPases interact with LRRK2 and hence function differently in LRRK2 mediated pathogenesis. Here we show that Rac1 and Rab29 specifically interact with LRRK2 with higher affinity for Rab29 and with different preference in functional domain binding. Mutant Rab29 but not Racl alters the endosome-to-TGN retrograde trafficking of a cargo protein cation-independent mannose-6-phosphate receptor(CI-M6 PR) and its stability. On the other hand, overexpressed wild type Rab29 but not Racl rescued the altered retrograde membrane trafficking induced by the pathogenic mutant LRRK2^(G2019 S). Furthermore,both Rac1 and Rab29 rescued neurite shortening in differentiated SH-SY5 Y cells induced by LRRK2^(G2019 S). Our study strongly suggests that Rac1 and Rab29 are involved in distinct functions as downstream effectors in LRRK2 signaling pathways.