LRRK2 activity is dysregulated in Parkinson's disease, but how it contributes to the pathogenesis is unknown. These authors show that Drosophila LRRK2 interacts with the Argonaute component (dAgo1) of the RNA-induced silencing complex. This is associated with reduced levels of dAgo1, interaction between phospho-4E-BP1 and hAgo2, and impairment of microRNA-mediated repression. This leads to overexpression of the cell cycle genes e2f1 and dp, and consequent degeneration of dopaminergic neurons.

These authors have developed a method that enables them to observe single-molecule fluorescent probes with subnanometre precision and accuracy using conventional far-field fluorescence imaging. The improved resolution will enable researchers to characterize single 'molecules' of large, multisubunit biological complexes in biologically relevant environments.

Few scientists realize that the enormous budget of the US Department of Defense includes sizeable funds for basic research. Eric Hand provides a guide for the uninitiated.