Disclosed are genes that, when overexpressed in cells expressing alpha-synuclein, either suppress or enhance alpha-synuclein mediated cellular toxicity. Compounds that modulate expression of these genes or activity of the encoded proteins can be used to inhibit alpha-synuclein mediated toxicity and used to treat or prevent synucleinopathies such as Parkinson's disease. Also disclosed are methods of identifying inhibitors of alpha-synuclein mediated toxicity.