The intestinal heme transporter revealed

The iron-containing porphyrin heme provides a rich source of dietary iron for mammals. The fact that animals can derive iron from heme implies the existence of a transporter that would transport heme from the gut lumen into intestinal epithelial cells. In this issue of Cell, Shayeghi, McKie, and co-workers (Shayeghi et al., 2005) now describe a heme transporter that is expressed in the apical region of epithelial cells in the mouse duodenum. Their identification of heme carrier protein 1 (HCP1) provides a major missing piece in our understanding of iron uptake and mammalian nutrition.