Copper transporter involved in copper acquisition and transport in leaves. Required for copper homeostasis and normal plant growth and development. Expressed in the root apex, lateral root primordia, embryo, trichomes, guard cells and pollen grains. Down-regulated by treatment with high concentrations of copper. Increased root length and pollen development defects. The increased root length and pollen development defects phenotypes of the mutants are completely and specifically reversed by copper addition. Belongs to the copper transporter (Ctr) (TC 1.A.56) family. SLC31A subfamily.