Karsten Boldt

Mutations in leucine-rich repeat kinase 2 (LRRK2) are the single most common cause of inherited Parkinson's disease. Little is known about its involvement in the pathogenesis of Parkinson's disease mainly because of the lack of knowledge about the physiological role of LRRK2. To determine the function of LRRK2, we studied the impact of short hairpin RNA-mediated silencing of LRRK2 expression in cortical neurons. Paired recording indicated that LRRK2 silencing affects evoked postsynaptic currents. Furthermore, LRRK2 silencing induces at the presynaptic site a redistribution of vesicles within the bouton, altered recycling dynamics, and increased vesicle kinetics. Accordingly, LRRK2 protein is present in the synaptosomal compartment of cortical neurons in which it interacts with several proteins involved in vesicular recycling. Our results suggest that LRRK2 modulates synaptic vesicle trafficking and distribution in neurons and in consequence participates in regulating the dynamics between vesicle pools inside the presynaptic bouton.

Nature Communications 6: Article number:7074 (2015); Published: 05 June 2015; Updated: 29 Marrch 2016 The financial support for this article was not fully acknowledged. The Acknowledgements should have included the following: PLB was supported by the National Institute for Health Research BiomedicalResearch Centre at Great Ormond Street Hospital for Children NHS Foundation Trust and University College London.

Cellular organelles provide opportunities to relate biological mechanisms to disease. Here we use affinity proteomics, genetics and cell biology to interrogate cilia: poorly understood organelles, where defects cause genetic diseases. Two hundred and seventeen tagged human ciliary proteins create a final landscape of 1,319 proteins, 4,905 interactions and 52 complexes. Reverse tagging, repetition of purifications and statistical analyses, produce a high-resolution network that reveals organelle-specific interactions and complexes not apparent in larger studies, and links vesicle transport, the cytoskeleton, signalling and ubiquitination to ciliary signalling and proteostasis. We observe sub-complexes in exocyst and intraflagellar transport complexes, which we validate biochemically, and by probing structurally predicted, disruptive, genetic variants from ciliary disease patients. The landscape suggests other genetic diseases could be ciliary including 3M syndrome. We show that 3M genes are involved in ciliogenesis, and that patient fibroblasts lack cilia. Overall, this organelle-specific targeting strategy shows considerable promise for Systems Medicine.