Intracellular iron pool (LIP)

The intracellular iron pool, often referred to as the labile iron pool (LIP), represents a dynamic fraction of non-protein-bound, redox-active iron ions (primarily Fe2+ and Fe3+) associated with low-molecular-weight chelators in microbial cells. This pool serves as a critical metabolic crossroads, providing the necessary iron for the assembly of iron-sulfur clusters and heme groups essential for DNA synthesis, respiration, and antioxidant defense. Because iron is strictly limited within the host environment as a form of nutritional immunity, microbes have evolved sophisticated acquisition systems, such as siderophores, to maintain this pool. In therapeutic contexts, the intracellular iron pool is targeted to inhibit microbial growth and virulence. Strategies include the use of high-affinity iron chelators to starve the pathogen, gallium compounds that act as iron mimetics to disrupt iron-dependent enzymatic reactions, and siderophore-drug conjugates (like Cefiderocol) that exploit iron transport pathways to deliver antibiotics directly into the cell. Disrupting this pool is particularly effective against multi-drug resistant bacteria, as iron remains an absolute requirement for pathogen survival and proliferation during infection (Source: PubMed, PMID: 30244314; Nature Reviews Microbiology, doi:10.1038/nrmicro3263).

Other names

Labile iron poolChelatable iron poolCytosolic iron poolFree iron poolRedox-active iron pool

Depletion of essential iron through chelation, competitive inhibition by iron mimetics (e.g., Gallium), or utilization of iron transport systems for 'Trojan horse' antibiotic delivery.