Table 1.

Iron Homeostasis-Related Proteins in Mammals

Protein	Function
ABCG2*	Possible BBM heme exporter; protection against possible heme toxicity
DCYTB	Ferric iron reduction for absorption across BBM by DMT1
DMT1	Ferrous iron/ H+ cotransporter on enterocyte BBM; possible Cu transport during iron depletion
FLVCR	Heme export across BLM into circulation
FPN1	Ferrous iron exporter on basolateral surface of enterocytes; hepcidin receptor
FTN	Iron storage within enterocytes; dietary form of iron found in legumes
HCP1	Possible BBM heme importer; also a physiological proton-coupled folate transporter
HEPH	Ferroxidase; BLM of enterocytes; functionally coupled to iron export by FPN1
HO-1/2	Oxidation of heme molecule to release ferrous iron in endosomes
HEPC	Iron-regulatory, liver-derived, peptide hormone; binds to FPN1 and causes its internalization and degradation
LTF	Iron-binding protein in breast milk; LTF receptor expressed on apical surface of enterocytes

^*ABCG2, breast cancer-resistance protein; DCYTB, duodenal cytochrome B; DMT1, divalent metal-ion transporter 1; FLVCR, feline leukemia virus, subgroup C, receptor; FPN1, ferroportin 1; FTN, ferritin; HCP1, heme carrier protein 1; HEPH, hephaestin; HO, heme oxygenase; HEPC, hepcidin; LTF, lactoferrin.