Any process involved in the maintenance of an internal steady state of iron ions within an organism or cell. [GOC:ai, GOC:jid, GOC:mah]
GO:0038023
signaling receptor activity
Receiving a signal and transmitting it in the cell to initiate a change in cell activity. A signal is a physical entity or change in state that is used to transfer information in order to trigger a response. [GOC:bf, GOC:signaling]
Enables the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: siderophore-iron(ferrioxamine)(out) + H+(out) = siderophore-iron(ferrioxamine)(in) + H+(in). [TC:2.A.1.16.1]
GO:0009279
cell outer membrane
A lipid bilayer that forms the outermost membrane of the cell envelope; enriched in polysaccharide and protein; the outer leaflet of the membrane contains specific lipopolysaccharide structures. [GOC:md, GOC:mtg_sensu, ISBN:0135712254]