Mammalian iron transport: an unexpected link between metal homeostasis and host defense

Iron deficiency and iron overload disorders are common in clinical practice. Both can result from perturbations in the flux of iron across the absorptive intestinal enterocyte. Until recently iron transport has been poorly understood. In 1997 two independent cloning strategies identified Nramp2 (DCT1) as the first mammalian transmembrane iron transporter. In this review we discuss evidence that Nramp-related proteins play essential roles in metal homeostasis and host defense.