In order to characterize the alterations in LRRK2 protein homo- and hetero-interactions in response to the kinase activating PD mutation G2019S, we used fluorescence fluctuation spectroscopy (FFS), fluorescence lifetime imaging microscopy (FLIM) with Förster resonance energy transfer (FRET), and total internal reflection fluorescence (TIRF) microscopy. Here, LRRK2 is linked to Parkinson disease.