Objective Parkinsons disease (PD) and dementia with Lewy bodies (DLB) are characterized by the accumulation of abnormal α-synuclein and ubiquitin in protein aggregates conforming Lewy bodies and Lewy neurites.These proteinaceous intracellular aggregates may contribute to subsequent dopaminergic neurodegeneration.The α-synuclein is a natively unfolded protein that is capable of self-aggregation to form both oligomers and fibrillar polymers with amyloid-like characteristics.Ubiquitin is an extremely conserved, 8.5 kD, 76 residue protein found in all eukaryotes.It has multiple functions but it is primarily involved in a pathway that regulates the bulk of intracellular protein turnover.It demonstrates that ubiquitin plays an important role in alpha-synuelein degradation.However, the feature and mechanism among ubiquitin and synuclein proteins in neurodegeneration are not clear.The present study is to investigate the characteristic ofubiquitin and interaction with synuclein.Methods The aggregation features and the interaction between ubiquitin and synuclein was identified by immunobloting and morphological assay.Results (1) Ubiquitin protein is aggregated and fibrillated under certain conditions, i.e., increasing time lag, high temperature, low pH and ferrous iron oxidation in vitro.(2) α-Synuclein WT appears bamboo-like longer fibril, while ubiquitin looks thin twisted thread, and can fuse and hybrid with α-synuclein fiIaments by immunoelectron microscopy assay.(3) In stable synuclein B 103 neuroblastoma cells, ubiquitin colocalized with synuclein in inclusion bodies and could accumulate and ubiquitinate with synuclein in certain conditions.Conclusion These results suggest that ubiquitin could self-aggregate and might interact with α-synuclein in neurodegeneration.