High-affinity iron transporter that plays a key role in the uptake of iron from the rhizosphere across the plasma membrane in the root epidermal layer. Acts as the principal regulator of iron homeostasis in planta. Also mediates the heavy metals uptake under iron-deficiency by its ability to transport cobalt, cadmium, manganese and/or zinc ions. Interacts with FREE1. Cycles constitutively between early endosomes and the plasma membrane and is targeted to the vacuole for degradation. Expressed in the external cell layers of the root including the lateral branching zone. Also detected in flowers before pollination. In roots by iron starvation. Monoubiquitinated on several Lys residues. Monoubiquitination controls trafficking from the plasma membrane and targeting to the vacuole. Plants exhibit a lethal chlorotic phenotype. Inhibited by cadmium and Fe(2+) ions and at 100-fold excess inhibited by cobalt, manganese and zinc ions. The availability of secondary non-iron metal substrates (Zn, Mn, and Co) controls the localization of IRT1 between the outer polar domain of the plasma membrane and early endosome/trans-Golgi network in root epidermal cells. May be due to an intron retention. Belongs to the ZIP transporter (TC 2.A.5) family. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus.