The Parkinson’s Disease Mutant E46K Enhances Alpha-Synuclein Phosphorylation in Mammalian Cell-Lines, in Yeast and In Vivo. [Cell Biology]

February 5th, 2015 by Mbefo, M., Fares, M.-B., Paleologou, K., Oueslati, A., Yin, G., Tenreiro, S., Pinto, M., Outeiro, T., Zweckstetter, M., Masliah, E., Lashuel, H. A.

Although α-synuclein (α-syn) phosphorylation has been considered as a hallmark of sporadic and familial Parkinson's disease (PD), little is known about the effect of PD-linked mutations on α-syn phosphorylation. In this study, we investigated the effect of the A30P, E46K, and A53T PD-linked mutations on α-syn phosphorylation at residues S87 and S129. Whereas the A30P and A53T mutants slightly affected pS129 levels compared to WT α-syn, the E46K mutation significantly enhanced S129 phosphorylation in yeast and mammalian cell lines. This effect was not due to the E46K mutant being a better kinase substrate, nor due to alterations in endogenous kinase levels, but mostly linked with enhanced nuclear and ER accumulation. Importantly, lentiviral mediated overexpression in mice also showed enhanced pS129 phosphorylation of the E46K mutant compared to WT α-syn, thus providing in vivo validation of our findings. Altogether, our findings suggest that the different PD-linked mutations may contribute to PD pathogenesis via different mechanisms.