Structural basis of ion transport and inhibition in ferroportin. Author Yaping Pan, Zhenning Ren, Shuai Gao, Jiemin Shen, Lie Wang, Zhichun Xu, Ye Yu, Preetham Bachina, Hanzhi Zhang, Xiao Fan, Arthur Laganowsky, Nieng Yan, Ming Zhou Publication Year 2020 Type Journal Article Abstract Ferroportin is an iron exporter essential for releasing cellular iron into circulation. Ferroportin is inhibited by a peptide hormone, hepcidin. In humans, mutations in ferroportin lead to ferroportin diseases that are often associated with accumulation of iron in macrophages and symptoms of iron deficiency anemia. Here we present the structures of the ferroportin from the primate Philippine tarsier (TsFpn) in the presence and absence of hepcidin solved by cryo-electron microscopy. TsFpn is composed of two domains resembling a clamshell and the structure defines two metal ion binding sites, one in each domain. Both structures are in an outward-facing conformation, and hepcidin binds between the two domains and reaches one of the ion binding sites. Functional studies show that TsFpn is an electroneutral H/Fe antiporter so that transport of each Fe is coupled to transport of two H in the opposite direction. Perturbing either of the ion binding sites compromises the coupled transport of H and Fe. These results establish the structural basis of metal ion binding, transport and inhibition in ferroportin and provide a blueprint for targeting ferroportin in pharmacological intervention of ferroportin diseases. Keywords Animals, Humans, Binding Sites, Protein Binding, Cryoelectron Microscopy, Iron, Ion Transport, Anemia, Iron-Deficiency, Cation Transport Proteins, Hepcidins Journal Nat Commun Volume 11 Issue 1 Pages 5686 Date Published 2020 Nov 10 ISSN Number 2041-1723 DOI 10.1038/s41467-020-19458-6 Alternate Journal Nat Commun PMCID PMC7655804 PMID 33173040 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML