This study resulted in the identification of a set of Ras-related in brain (Rab) GTPases as endogenous LRRK2 substrates [16], a finding that laid the groundwork for subsequent initiatives exploring the role of Rab proteins in PD neurodegeneration [17,18,19] and resulted in the generation of critical laboratory tools and reagents that are being distributed across the world to enable further studies of this emerging cellular pathway. This evidence concerns the gene LRRK2 and Parkinson disease.