The yeast CLC chloride channel functions in cation homeostasis

A defect in the yeast GEF1 gene, a CLC chloride channel homolog leads to an iron requirement and cation sensitivity, The iron requirement is due to a failure to load Cu2+ onto a component of the iron uptake system, Fet3, This profess, which requires both Gef1 and the Menkes disease Cu2+-ATPase yeast homolog Ccc2, occurs in late-or post-Golgi vesicles, where Gef1 and Ccc2 are localized, The defects of gef1 mutants can be suppressed by the introduction of Torpedo marmorata CLC-0 or arabidopsis thaliana CLC-c and -d chloride channel genes, The functions of Gef1 in cation homeostasis provide clues to the understanding of diseases caused by chloride channel mutations in humans and cation toxicity in plants.