LRRK2-mediated phosphorylation and thermal stability of Rab12 are regulated by bound nucleotides

An abnormal increase in the phosphorylation of Rab12 by leucine-rich repeat kinase 2 (LRRK2), a serine/ threonine kinase genetically linked to Parkinson's disease (PD), has been implicated in the pathogenesis of PD, although the underlying mechanism remains unclear. In this report, we show that LRRK2 phos-phorylates Rab12 more efficiently in its GDP-bound form than in its GTP-bound form using an in vitro phosphorylation assay. This observation suggests that LRRK2 recognizes the structural difference of Rab12 caused by the bound nucleotide and that Rab12 phosphorylation inhibits its activation. Circular dichroism data revealed that Rab12, in its GDP-bound form, is more susceptible to heat-induced dena-turation than its GTP-bound form, which was exacerbated at basic pH. Differential scanning fluorimetry showed that heat-induced denaturation of Rab12 in its GDP-bound form occurs at a lower temperature than in its GTP-bound form. These results suggest that the type of nucleotide bound to Rab12 determines the efficiency of LRRK2-mediated phosphorylation and the thermal stability of Rab12, and provide in-sights into elucidating the mechanism of the abnormal increase in Rab12 phosphorylation.(c) 2023 Elsevier Inc. All rights reserved.

Automated summary

In this study, it was found that the abnormal increase in phosphorylation of Rab12 by LRRK2 is attributed to the structural differences caused by the bound nucleotide, and that Rab12 phosphorylation inhibits its activation. The research also showed that Rab12 in its GDP-bound form is more susceptible to heat-induced denaturation and has a lower thermal stability compared to its GTP-bound form. These findings provide insights into unraveling the mechanism behind the abnormal increase in Rab12 phosphorylation.