Aggregates from mutant and wild-type α-synuclein proteins and NAC peptide induce apoptotic cell death in human neuroblastoma cells by formation of β-sheet and amyloid-like filaments

α-Synuclein (α-syn) protein and a fragment of it, called NAC, have been found in association with the pathological lesions of a number of neurodegenerative diseases. Recently, mutations in the α-syn gene have been reported in families susceptible to an inherited form of Parkinson's disease. We have shown that human wild-type α-syn, mutant α-syn(Ala30Pro) and mutant α-syn(Ala53Thr) proteins can self-aggregate and form amyloid-like filaments. Here we report that aggregates of NAC and α-syn proteins induced apoptotic cell death in human neuroblastoma SH-SY5Y cells. These findings indicate that accumulation of α-syn and its degradation products may play a major role in the development of the pathogenesis of these neurodegenerative diseases.