The Extracellular α-Synuclein and its Biological Significance

Lin Guo and Xuechu Zhen

Abstract

α-synuclein plays an important role in the development of Parkinson’s disease (PD). It was believed that α-synuclein elicits its effects in the neuronal cytosol. However, the finding of extracellular α-synuclein expands the orthodox spectrum. The α-synuclein can be secreted via the multi-vesicle bodies-mediated exosome and the recycling-endosome pathway. In the intercellular milieu, the secreted α-synuclein is degraded by enzymes or engulfed by neighboring cells. The remaining α-synuclein can induce the neurotoxicity, activate microglia, and promote the pathogenesis of Parkinson’s disease. In the review, we focus on the recent findings of extracellular α-synuclein and its biological significance.