Yeast two-hybrid assays using the end-binding 1 (EB1) protein of Giardia lamblia as bait led to the isolation of four independent clones encoding gamma-giardin, a neurogenic Notch-like protein, and two hypothetical proteins. Interactions between EB1 and the isolated proteins were confirmed by co-immunoprecipitation of in vitro-synthesized candidate proteins and EB1. Localization of these isolated proteins in G. lamblia was examined by immunofluorescence assays, indicating that they were predominantly present in cytoskeletal structures of G. lamblia. These results suggest that EB1 protein functions via interaction with the cytoskeletal components of G. lamblia.