Versatile Structures of α-Synuclein

alpha-Synuclein (alpha-syn) is an intrinsically disordered protein abundantly distributed in presynaptic terminals. Aggregation of alpha-syn into Lewy bodies (LB) is a molecular hallmark of Parkinson's disease (PD). alpha-Syn features an extreme conformational diversity, which adapts to different conditions and fulfills versatile functions. However, the molecular mechanism of alpha-syn transformation and the relation between different structural species and their functional and pathogenic roles in neuronal activities and PD remain unknown. In this mini-review, we summarize the recent discoveries of alpha-syn structures in the membrane-bound state, in cytosol, and in the amyloid state under physiological and pathological conditions. From the current knowledge on different structural species of alpha-syn, we intend to find a clue about its function and toxicity in normal neurons and under disease conditions, which could shed light on the PD pathogenesis.