Disclosed are mammalian neuronal cells expressing alpha synuclein as well as methods of screening to identify compounds that decrease toxicity induced by alpha synuclein expression. Compounds identified by such screens can be used to treat or prevent synucleinopathies such as Parkinson's disease, familial Parkinson's disease, Lewy body disease, the Lewy body variant of Alzheimer's disease, dementia with Lewy bodies, multiple system atrophy, or the Parkinsonism-dementia complex of Guam.