Structural basis of ion transport and inhibition in ferroportin.

TitleStructural basis of ion transport and inhibition in ferroportin.
Publication TypeJournal Article
Year of Publication2020
AuthorsPan, Y, Ren, Z, Gao, S, Shen, J, Wang, L, Xu, Z, Yu, Y, Bachina, P, Zhang, H, Fan, X, Laganowsky, A, Yan, N, Zhou, M
JournalNat Commun
Volume11
Issue1
Pagination5686
Date Published2020 11 10
ISSN2041-1723
KeywordsAnemia, Iron-Deficiency, Animals, Binding Sites, Cation Transport Proteins, Cryoelectron Microscopy, Hepcidins, Humans, Ion Transport, Iron, Protein Binding
Abstract

<p>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.</p>

DOI10.1038/s41467-020-19458-6
Alternate JournalNat Commun
PubMed ID33173040
PubMed Central IDPMC7655804
Grant ListR01 DK122784 / DK / NIDDK NIH HHS / United States