Disclosed are yeast cells expressing TAR DNA-binding protein 43 (TDP-43) and methods of screening yeast cells to identify compounds that prevent or suppress TDP-43-induced toxicity, compounds that inhibit the formation or maintenance of cytoplasmic inclusions of TDP-43, genetic suppressors or enhancers of TDP-43-induced toxicity, and genetic suppressors or enhancers of the formation or maintenance of cytoplasmic inclusions of TDP-43. Compounds identified by such screens can be used to treat or prevent TDP-43 proteinopathies such as frontotemporal lobar degeneration or amyotrophic lateral sclerosis.