Lipocalin-2/NGAL (Neutrophil Gelatinase-associated Lipocalin) is a secreted carrier protein that acts in the innate immune response, differentiation, tumorigenesis, and cell survival. It is induced in macrophages, glial cells, and epithelial cells during inflammation, anemia, and hypoxia. Lipocalin-2 binds catecholate siderophores which are secreted by bacteria and are required for bacterial iron uptake. Lipocalin-2 functions as a bacteriostatic agent in the innate immune response by limiting the bacterial iron supply. Iron uptake by Lipocalin-2 into mammalian cells is important for the regulation of iron-sensitive gene transcription. In the kidney, Lipocalin-2-mediated iron trafficking is required for protection from renal injury.