Biochemical and kinetic properties of the complex Roco G-protein cycle.

TitleBiochemical and kinetic properties of the complex Roco G-protein cycle.
Publication TypeJournal Article
Year of Publication2018
AuthorsWauters, L., S. Terheyden, B. K. Gilsbach, M. Leemans, P. S. Athanasopoulos, G. Guaitoli, A. Wittinghofer, C. Johannes Gloeckner, W. Versées, and A. Kortholt
JournalBiol Chem
Date Published2018 11 27
KeywordsGTP-Binding Proteins, Guanosine Triphosphate, Humans, Hydrolysis, Kinetics, Leucine-Rich Repeat Serine-Threonine Protein Kinase-2, Mutation

Roco proteins have come into focus after mutations in the gene coding for the human Roco protein Leucine-rich repeat kinase 2 (LRRK2) were discovered to be one of the most common genetic causes of late onset Parkinson's disease. Roco proteins are characterized by a Roc domain responsible for GTP binding and hydrolysis, followed by a COR dimerization device. The regulation and function of this RocCOR domain tandem is still not completely understood. To fully biochemically characterize Roco proteins, we performed a systematic survey of the kinetic properties of several Roco protein family members, including LRRK2. Together, our results show that Roco proteins have a unique G-protein cycle. Our results confirm that Roco proteins have a low nucleotide affinity in the micromolar range and thus do not strictly depend on G-nucleotide exchange factors. Measurement of multiple and single turnover reactions shows that neither Pi nor GDP release are rate-limiting, while this is the case for the GAP-mediated GTPase reaction of some small G-proteins like Ras and for most other high affinity Ras-like proteins, respectively. The KM values of the reactions are in the range of the physiological GTP concentration, suggesting that LRRK2 functioning might be regulated by the cellular GTP level.

Alternate JournalBiol. Chem.
PubMed ID30067506
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