Synapsins regulate α-synuclein functions

The normal function of alpha-synuclein (alpha-syn) remains elusive. Although recent studies suggest alpha-syn as a physiologic attenuator of synaptic vesicle (SV) recycling, mechanisms are unclear. Here, we show that synapsin-a cytosolic protein with known roles in SV mobilization and clustering-is required for presynaptic functions of alpha-syn. Our data offer a critical missing link and advocate a model where alpha-syn and synapsin cooperate to cluster SVs and attenuate recycling.