A Neo-Substrate that Amplifies Catalytic Activity of Parkinson’s-Disease-Related Kinase PINK1

•PINK1 activity is amplified by neo-substrate kinetin triphosphate (KTP)•KTP amplifies activity of PINK1wt and Parkinson’s-disease-related mutant PINK1G309D•Kinetin reduces mitochondrial motility in a PINK1-dependent manner•Kinetin inhibits apoptosis of human neurons in a PINK1-dependent manner

SummaryMitochondria have long been implicated in the pathogenesis of Parkinson’s disease (PD). Mutations in the mitochondrial kinase PINK1 that reduce kinase activity are associated with mitochondrial defects and result in an autosomal-recessive form of early-onset PD. Therapeutic approaches for enhancing the activity of PINK1 have not been considered because no allosteric regulatory sites for PINK1 are known. Here, we show that an alternative strategy, a neo-substrate approach involving the ATP analog kinetin triphosphate (KTP), can be used to increase the activity of both PD-related mutant PINK1G309D and PINK1WT. Moreover, we show that application of the KTP precursor kinetin to cells results in biologically significant increases in PINK1 activity, manifest as higher levels of Parkin recruitment to depolarized mitochondria, reduced mitochondrial motility in axons, and lower levels of apoptosis. Discovery of neo-substrates for kinases could provide a heretofore-unappreciated modality for regulating kinase activity.

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