SLC40A1 and infection: In case of infection with intracellular bacteria such as S.tm., macrophage re-program their iron metabolism by increasing the expression of the only known iron exporter ferroportin (Fpn1) to promote iron egress, but also express several host resistance proteins aiming to limit iron access for bacteria, such as lipocalin-2 (Lcn2), which binds bacterial enterobactin-type siderophores, or the iron binding protein lactoferrin or natural resistance-associated macrophage protein 1 (Nramp1), which induces transcellular iron shifting [20,21,22,23,24,25].