LRRK2 and Parkinson disease: A subset of G-proteins from the Ras-related small GTPase superfamily17 was reported as phosphorylation substrates of the LRRK2 Ser/Thr kinase.2,3 Among these, pThr73 RAB10 was validated as an LRRK2 substrate18 showing elevated endogenous phosphorylation levels in a large set of R1441G carriers, PD-manifesting and non-manifesting, but not in G2019S subjects.19 Moreover, pThr73 RAB10 represents a readout for LRRK2 pharmacological inhibition using Mli-2 or DNL201.20,21 In addition, RAB2922,23 and, more recently, RAB1224,25 and RAB32,26 have been described as critical upstream LRRK2 activators.