Previous studies have demonstrated an importance of alpha-synuclein as a modulator of various mechanisms implicated in chemical neurotransmission but information about other two synuclein family members’ involvement in molecular processes taking place in presynaptic terminals is limited. Here we demonstrated that dopamine uptake by synaptic vesicles isolated from the striatum of mice lacking beta-synuclein was significantly reduced. Reciprocally, reintroduction, either in vivo or in vitro, of beta-synuclein but not alpha- or gamma-synuclein improved uptake by vesicles isolated from the striatum of triple alpha/beta/gamma-synuclein deficient mice. Proteomic analysis of synuclein-free and beta-synuclein-only-containing synaptic vesicles suggested that mechanistically, beta-synuclein potentiates vesicular monoamine transporter 2 (VMAT2)-dependent dopamine uptake by assembling specific multiprotein complexes comprised of resident vesicular proteins and transiently associated, predominantly cytosolic proteins. The increased availability of such complexes on the surface of striatal synaptic vesicles lacking other synucleins should also promote sequestration of 1-methyl-4-phenylpyridinium (MPP+), a toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which explains the resistance of dopaminergic neurons of substantia nigra lacking alpha-synuclein and/or gamma-synuclein to this neurotoxin.