Structure of the GTPase and GDI domains of FeoB, the ferrous iron transporter of Legionella pneumophila.

Prokaryotic pathogens have developed specialized mechanisms for efficient uptake of ferrous iron (Fe(2+)) from the host. In Legionella pneumophila, the causative agent of Legionnaires' disease, the transmembrane GTPase FeoB plays a key role in Fe(2+) acquisition and virulence. FeoB consists of a membrane-embedded core and an N-terminal, cytosolic region (NFeoB).

The translocated Salmonella effector proteins SseF and SseG interact and are required to establish an intracellular replication niche.

The facultative intracellular pathogen Salmonella enterica causes a variety of diseases, including gastroenteritis and typhoid fever. Inside epithelial cells, Salmonella replicates in vacuoles, which localize in the perinuclear area in close proximity to the Golgi apparatus. Among the effector proteins translocated by the Salmonella pathogenicity island 2-encoded type III secretion system, SifA and SseG have been shown necessary but not sufficient to ensure the intracellular positioning of Salmonella vacuoles.