A comprehensive, unbiased inventory of synuclein forms present in Lewy bodies 
from patients with dementia with Lewy bodies was carried out using 
two-dimensional immunoblot analysis, novel sandwich enzyme-linked immunosorbent 
assays with modification-specific synuclein antibodies, and mass spectroscopy. 
The predominant modification of alpha-synuclein in Lewy bodies is a single 
phosphorylation at Ser-129. In addition, there is a set of characteristic 
modifications that are present to a lesser extent, including ubiquitination at 
Lys residues 12, 21, and 23 and specific truncations at Asp-115, Asp-119, 
Asn-122, Tyr-133, and Asp-135. No other modifications are detectable by tandem 
mass spectrometry mapping, except for a ubiquitous N-terminal acetylation. Small 
amounts of Ser-129 phosphorylated and Asp-119-truncated alpha-synuclein are 
present in the soluble fraction of both normal and disease brains, suggesting 
that these Lewy body-associated forms are produced during normal metabolism of 
alpha-synuclein. In contrast, ubiquitination is only detected in Lewy bodies and 
is primarily present on phosphorylated synuclein; it therefore likely occurs 
after phosphorylated synuclein has deposited into Lewy bodies. This invariant 
pattern of specific phosphorylation, truncation, and ubiquitination is also 
present in the detergent-insoluble fraction of brain from patients with familial 
Parkinson's disease (synuclein A53T mutation) as well as multiple system 
atrophy, suggesting a common pathogenic pathway for both genetic and sporadic 
Lewy body diseases. These observations are most consistent with a model in which 
preferential accumulation of normally produced Ser-129 phosphorylated 
alpha-synuclein is the key event responsible for the formation of Lewy bodies in 
various Lewy body diseases.