Mechanism of Ca2+ transport by ferroportin
- Resource Type
- article
- Authors
- Jiemin Shen; Azaan Saalim Wilbon; Ming Zhou; Yaping Pan
- Source
- eLife, Vol 12 (2023)
- Subject
- SLC40
structure
cryo-EM
membrane transport
calcium
iron
Medicine
Science
Biology (General)
QH301-705.5
- Language
- English
- ISSN
- 2050-084X
Ferroportin (Fpn) is a transporter that releases ferrous ion (Fe2+) from cells and is important for homeostasis of iron in circulation. Export of one Fe2+ by Fpn is coupled to import of two H+ to maintain charge balance. Here, we show that human Fpn (HsFpn) binds to and mediates Ca2+ transport. We determine the structure of Ca2+-bound HsFpn and identify a single Ca2+ binding site distinct from the Fe2+ binding sites. Further studies validate the Ca2+ binding site and show that Ca2+ transport is not coupled to transport of another ion. In addition, Ca2+ transport is significantly inhibited in the presence of Fe2+ but not vice versa. Function of Fpn as a Ca2+ uniporter may allow regulation of iron homeostasis by Ca2+.