Culturing and passaging of adherent cell lines were carried out using aseptic technique in CL1 or CL2 (for PBMC isolation) biological safety cabinets. All cells were incubated in a 37°C incubator with 5% CO2. Cell lines were regularly tested for mycoplasma contamination. For western blot assay, the cells were seeded in 6-well plates. For immunoprecipitation of LRRK2, SH-SY5Y cells (cultured in DMEM-F12, supplemented with 15% (v/v) FBS, 100 U/ml penicillin and 100 µg/ml streptomycin, 1X non-essential amino acids, and 1 mM sodium pyruvate) were seeded in a 10-cm dish. All cells were treated with the indicated compounds such that the final concentration of DMSO was 0.1%. Following the treatment of cells with compounds at indicated concentrations and time periods, the media was removed and the cells were washed with PBS and lysed in 100 µl ice-cold complete lysis buffer containing 50 mM Tris-HCl pH 7.4, 1 mM EGTA, 10 mM 2-glycerophosphate, 50 mM sodium fluoride, 5 mM sodium pyrophosphate, 270 mM sucrose, supplemented with 1 μg/ml microcystin-LR, 1 mM sodium orthovanadate, complete EDTA-free protease inhibitor cocktail (Roche) and 1% (v/v) Triton X-100. The cells were immediately placed on ice and were scraped and collected into 1.5 ml Eppendorf tubes. Cell lysates were incubated on ice for 10 minutes prior to centrifugation at 15,000 g at 4°C for 15 minutes. The cell pellet was discarded, and supernatant was collected for analysis by quantitative immunoblotting. For long term storage, the supernatant was flash frozen and stored at -80°C. Protein concentrations of cell lysates were determined using the Bradford assay.