α-Synuclein is a member of a family of small, soluble proteins that also include β-, and γ-Synuclein.  α-Synuclein is predominantly expressed in neurons of the central nervous system, specifically in the presynaptic region of nerve terminals.  This protein cycles between a free, partially unfolded form and a helical, membrane-bound form.  α-Synuclein can aggregate in vivo and in vitro, forming various oligomeric species and fibrillar and amorphous aggregates.  The fibrils and amyloidal forms are major components of Lewy Bodies and have been linked to the pathogenesis of Parkinson's disease dementia.  α-Synuclein aggregates can also be found associated with amyloid plaques in Alzheimer's disease.  This untagged recombinant protein may be used as an in vitro substrate for various Ubiquitin E3 ligases.