MTP1 mops up excess zinc in Arabidopsis cells

The MTP1 protein of Arabidopsis thaliana belongs to a ubiquitous family of transition metal transporters that extrude metal ions from the cytoplasm. In a recent publication, Yoshihiro Kobae and colleagues show that AtMTP1 localizes to the vacuolar membrane in Arabidopsis roots and suspension-cultured cells. They demonstrate that the mtp1-1 mutant is hypersensitive to zinc and complement the mutant by transforming it with the MTP1 coding sequence downstream of a constitutive (35S) promoter.