LRRK2 Parkinson disease mutations enhance its microtubule association.

Dominant missense mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common genetic causes of Parkinson disease (PD) and genome-wide association studies identify LRRK2 sequence variants as risk factors for sporadic PD. Intact kinase function appears critical for the toxicity of LRRK2 PD mutants, yet our understanding of how LRRK2 causes neurodegeneration remains limited. We find that most LRRK2 PD mutants abnormally enhance LRRK2 oligomerization, causing it to form filamentous structures in transfections of cell lines or primary neuronal cultures. Strikingly, ultrastructural analyses, including immuno-electron microscopy and electron microscopic tomography, demonstrate that these filaments consist of LRRK2 recruited onto part of the cellular microtubule network in a well-ordered, periodic fashion. Like LRRK2-related neurodegeneration, microtubule association requires intact kinase function and the WD40 domain, potentially linking microtubule binding and neurodegeneration. Our observations identify a novel effect of LRRK2 PD mutations and highlight a potential role for microtubules in the pathogenesis of LRRK2-related neurodegeneration.

The biology and pathology of the familial Parkinson's disease protein LRRK2.

Parkinson's disease (PD) is typically a sporadic illness, but the past decade has witnessed the identification of mutations responsible for multiple familial forms of the disease. The proposed functions of some of these genes (e.g., E3 ubiquitin ligase, redox-dependent chaperone) have led to the hypothesis that dysfunction of protein quality control pathways contributes to PD neurodegeneration. However, the key signaling events that act downstream of misfolded proteins to cause cell death remain poorly defined. The discovery of the familial PD kinase leucine-rich repeat kinase 2 (LRRK2) holds great promise for the elucidation of signaling events relevant to PD neurodegeneration. This review will summarize current knowledge of the clinical and cell biological features of LRRK2, the most common inherited cause of Parkinsonism.

The Parkinson disease protein leucine-rich repeat kinase 2 transduces death signals via Fas-associated protein with death domain and caspase-8 in a cellular model of neurodegeneration.

Neurodegenerative illnesses such as Parkinson and Alzheimer disease are an increasingly prevalent problem in aging societies, yet no therapies exist that retard or prevent neurodegeneration. Dominant missense mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common genetic cause of Parkinson disease (PD), but the mechanisms by which mutant forms of LRRK2 disrupt neuronal function and cause cell death remain poorly understood. We report that LRRK2 interacts with the death adaptor Fas-associated protein with death domain (FADD), and that in primary neuronal culture LRRK2-mediated neurodegeneration is prevented by the functional inhibition of FADD or depletion of caspase-8, two key elements of the extrinsic cell death pathway. This pathway is activated by disease-triggering mutations, which enhance the LRRK2-FADD association and the consequent recruitment and activation of caspase-8. These results establish a direct molecular link between a mutant PD gene and the activation of programmed cell death signaling, and suggest that FADD/caspase-8 signaling contributes to LRRK2-induced neuronal death.