α-Synuclein regulates the partitioning between tubulin dimers and microtubules at neuronal growth cone

The partitioning between tubulin dimers and microtubules is fundamental for the regulation of several neuronal activities, from neuronal polarization and processes extension to growth cone remodelling. This phenomenon is modulated by several proteins, including the well-known microtubule destabilizer Stathmin. We recently demonstrated that α-Synuclein, a presynaptic protein associated to Parkinson's disease, shares structural and functional properties with Stathmin, and we showed that α-Synuclein acts as a foldable dynamase. Here, we pinpoint the impact of wild type α-Synuclein on the partitioning between tubulin dimers and microtubules and show that Parkinson's disease-linked mutants lose this capability. Thus, our results indicate a new role for α-Synuclein in regulating microtubule system and support the concept that microtubules and α-Synuclein are partners in the modulation of neuronal health and degenerative processes. Furthermore, these data strengthen our hypothesis of the existence of a functional redundancy between α-Synuclein and Stathmin.