Strategies of Intracellular Pathogens for Obtaining Iron from the Environment

Table 1

Iron sources and mechanisms of uptake, transport, and regulation used by intracellular parasites.

Parasite	Iron sources	Mechanisms of iron acquisition	Transport	Regulation
Francisella tularensis	Tf	Receptors (TfR1)	Ferrireductase/DMT-1	IRP1-IRP2
	Fe^3+	iron reductase, siderophores	Fs1E
	Fe^2+	Receptors, iron reductase?	FupA
	Lf	Receptors, iron reductase?	Ferrireductase/DMT-1?
Salmonella spp.	Heme	Heme-oxygenase-1?	Porins?	FtnA, FtnB, FtnC, FtnD
	Tf	siderophores (enterobactin,	FepBCDG	sitABCD/Fur
	Fe^3+	enterochelin)/IronN and FepA	Feo
	Fe^2+	Phagocytosis
Chlamydia	Tf	Receptors?	tonB analogue?	IRP-1/IRE?
	Ft	Receptors?, iron reductase?	Host Fe-transport pathways?
		Receptors?	ABC transport systems?
		Siderophores?
Neisseria spp.	Tf	Receptors (TbpA, TbpB)	FetA	Fur
	Lf	Receptors (LbpA, LbpB)	MpeR
	haptoglobin-Hb	Siderophores (enterobactin Salmochelin)	HmbR
Legionella pneumophila	Fe^3+	Siderophores	Feo AB/system	Fur?
	Fe^2+	iron reductase	PerR/Fur
	Tf and Ft?	iron reductase?	Lpp_2867
Shigella spp.	Tf	Siderophores	Feo	ArcA and FNR
	Fe^3+, Fe^3+	iron reductase	Feo, Sit, luc	Fur
	Heme	iron reductase	Shu
	LF
Listeria monocytogenes	Hb	HupDGC	Fhu	Fri/Fur
	Hemin	HupDGC	Fhu	PerR
	Ferric citrate	iron reductase	Ferric citrate systems
	Fe-proteins?	Siderophores, iron reductase	Fur, ABC transporters
Coxiella burnetii	?	?	?	Bacterioferritins
				Fur
Mycobacterium spp.	Ferric dicitrate	Salicylic acid	IrtAB	Bacterioferritins
	Tf, Lf, Ft	Citric acid	Mramp	FurA, FurB
		Siderophores		IdeR
Candida spp.	Heme	Heme-binding protein (Dap1)	Sit1 (iron transporter)
	Tf; Ft	Fe^3+ reductases, Fe^2+transporter		Sfu1
	Hemin
Cryptococcus neoformans	Tf	Iron reductase, iron permeases	Cft1 and Cfo1	Cir1
	Heme	Hemophores, Heme receptors	Cig1 and the ESCRT
	Ft
Leishmania spp.	Heme, Hemin	LHR1	LIT1 transporter	?
	Tf?	Fe^3+ reductase 1 (LFR1),
	Lf
Trypanosoma spp.	Tf	Receptors (TfR)/endocytosis	ESAG6, ESAG7	IRP/IRE