Sequential screening nominates the Parkinson's disease associated kinase LRRK2 as a regulator of Clathrin-mediated endocytosis

George R Heaton,Natalie Landeck,Adamantios Mamais,Mike A Nalls,Jonathon Nixon-Abell,Ravindran Kumaran,Alexandra Beilina,Laura Pellegrini,Yan Li,Kirsten Harvey,Mark R Cookson

doi:10.1016/j.nbd.2020.104948

Abstract

Mutations in leucine-rich repeat kinase 2 (LRRK2) are an established cause of inherited Parkinson's disease (PD). LRRK2 is expressed in both neurons and glia in the central nervous system, but its physiological function(s) in each of these cell types is uncertain. Through sequential screens, we report a functional interaction between LRRK2 and Clathrin adaptor protein complex 2 (AP2). Analysis of LRRK2 KO tissue revealed a significant dysregulation of AP2 complex components, suggesting LRRK2 may act upstream of AP2. In line with this hypothesis, expression of LRRK2 was found to modify recruitment and phosphorylation of AP2. Furthermore, expression of LRRK2 containing the R1441C pathogenic mutation resulted in impaired clathrin-mediated endocytosis (CME). A decrease in activity-dependent synaptic vesicle endocytosis was also observed in neurons harboring an endogenous R1441C LRRK2 mutation. Alongside LRRK2, several PD-associated genes intersect with membrane-trafficking pathways. To investigate the genetic association between Clathrin-trafficking and PD, we used polygenetic risk profiling from IPDGC genome wide association studies (GWAS) datasets. Clathrin-dependent endocytosis genes were found to be associated with PD across multiple cohorts, suggesting common variants at these loci represent a cumulative risk factor for disease. Taken together, these findings suggest CME is a LRRK2-mediated, PD relevant pathway.

Highlights

Parkinson’s disease (PD) is a common, age-dependent neurodegenerative disease characterized in part by nigral neuronal loss and motor symptoms
We suggest adaptor protein complex 2 (AP2)-Leucine-rich repeat kinase 2 (LRRK2) interactions are important for the regulation of clathrin-mediated endocyto
These findings contribute to the current understanding of LRRK2 biology and suggest dysfunction of clathin-mediated endocytosis is relevant to PD pathogenesis

Summary

Introduction

PD is a common, age-dependent neurodegenerative disease characterized in part by nigral neuronal loss and motor symptoms. The protein encoded by the LRRK2 gene, Leucine-rich repeat kinase 2 (LRRK2), is a 286kDa multi domain protein belonging to the ROCO family.[7] All ROCO proteins are characterised by a GTP binding domain (Ras of complex proteins, Roc), followed in tandem by a C-terminal of Roc domain (COR).[8] LRRK2 contains a kinase and multiple protein-protein interaction domains These include amino-terminal armadillo and ankyrin repeats, followed by 13 leucine rich repeat regions (LRR) and 7 WD40 repeats at the C-terminus.[9,10] To date, all mutations found to segregate with PD in families are clustered within the catalytic domains and have been found to alter the inherent biochemical properties of LRRK2. Despite intensive study into the physiological function of LRRK2, a consensus on how LRRK2 acts within cells and how pathogenic mutations compromise this function has yet to be achieved

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