The ATX1 deletion strain of Saccharomyces cerevisiae is more resistant to Cd2+ than the wild-type. To investigate the function of Atx1 in Cd2+ toxicity, we used a metal-binding assay to study the interaction between Atx1 and Cd2+ in vitro. Using circular dichroism and two-hybrid analyses, we found that Atx1 can bind Cd2+ specifically and that Cd2+ binding to Atx1 affects the physical interaction between Atx1 and Ccc2. These results imply that Atx1 delivers Cd2+ to Ccc2 and that this delivery is, at least in part, responsible for Cd2+ toxicity in S. cerevisiae.