Fig. 6.

The ferroxidase-dependent step in mammalian iron trafficking: managing iron on the way out. Presented within the context of either an epithelial or endothelial cell (e.g. enterocyte or brain microcapillary), managing the efflux step relies on hephaestin (Hp) or ceruloplasmin (Cp) ferroxidation of the Fpn-trafficked Fe²⁺. In one model of this step, the Fe³⁺ product is channeled to a recipient ferric iron chelator, e.g. apo-transferrin (Tf) in an associative mechanism comparable to the fungal Fet, Ftr uptake pathway.