C. The "triton X-100" fraction was used as input for LRRK2 immunoprecipitation, with subsequent detection of total Rab10 and pT73-Rab10 proteins in LRRK2:Rab10 immunocomplexes using SDS-PAGE (TGX gels). To measure the stoichiometry of pT73-Rab10 to total Rab10, the same immunocomplexes were analyzed using phos-tag SDS-PAGE method, with unphosphorylated eGFP(N-term)-Rab10 migrating below the phospho-Rab10 protein. Immunoblots are representative of three independent experiments, with similar results obtained. 