Neutrophil gelatinase-associated lipocalin (NGAL) expression is dependent on the tumor-associated sigma-2 receptor S2RPgrmc1.
Authors: Mir SU, Jin L, Craven RJ
J. Biol. Chem., 2012;287(18):14494-501.
Species: Human
Sample Type: Whole Cells
Application: WB
Lipocalin 2 expression is associated with aggressive features of endometrial cancer.
Authors: Mannelqvist M, Stefansson I, Wik E, Kusonmano K, Raeder M, Oyan A, Kalland K, Moses M, Salvesen H, Akslen L
BMC Cancer, 2012;12(0):169.
Species: Human
Sample Type: Whole Tissue
Application: IHC Paraffin-embedded
Low expression of the IL-23/Th17 pathway in atopic dermatitis compared to psoriasis.
Authors: Guttman-Yassky E, Lowes MA, Fuentes-Duculan J, Zaba LC, Cardinale I, Nograles KE, Khatcherian A, Novitskaya I, Carucci JA, Bergman R, Krueger JG
J. Immunol., 2008;181(10):7420-7.
Species: Human
Sample Type: Whole Tissue
Application: IHC Frozen
Urinary biomarkers predict brain tumor presence and response to therapy.
Authors: Smith ER, Zurakowski D, Saad A, Scott RM, Moses MA
Clin. Cancer Res., 2008;14(8):2378-86.
Species: Human
Sample Type: Whole Tissue
Application: IHC Paraffin-embedded
Neutrophil gelatinase-associated lipocalin is expressed in osteoarthritis and forms a complex with matrix metalloproteinase 9.
Authors: Gupta K, Shukla M, Cowland JB, Malemud CJ, Haqqi TM
Arthritis Rheum., 2007;56(10):3326-35.
Species: Human
Sample Type: Synovial Fluid
Application: WB
Urinary lipocalin-2 is associated with renal disease activity in human lupus nephritis.
Authors: Pitashny M, Schwartz N, Qing X, Hojaili B, Aranow C, Mackay M, Putterman C
Arthritis Rheum., 2007;56(6):1894-903.
Species: Human
Sample Type: Urine
Application: WB

Members of Lipocalin family share a highly conserved fold with an eight-stranded antiparallel beta barrel, and act as a transporters, carrying small molecules to specific cells (1). Lipocalin-2, also known as Neutrophil Gelatinase-Associated Lipocalin (NGAL), was originally identified as a component of neutrophil granules (2). It is a 25 kDa protein existing in monomeric and homo- and heterodimeric forms, the latter as a dimer with human neutrophil gelatinases (MMP-9) (2). Its expression has been observed in most tissues normally exposed to microorganism, and its synthesis is induced in epithelial cells during inflammation (3). Lipocalin-2 has been implicated in a variety of processes including cell differentiation, tumorigenesis, and apoptosis (3-5). Studies indicate that Lipocalin-2 binds a bacterial catecholate sidropore bound to ferric ion such as enterobactin with a subnanomolar dissociation constant (K_d = 0.41 nM) (6). The bound ferric enterobactin complex breaks down slowly in a month into dihydroxybenzoyl serine and dihydroxybenzoic acid (DHBA). It also binds to a ferric DHBA complex with much less K_d values (7.9 nM) (6). Secretion of Lipocalin‑2 in immune cells increases by stimulation of Toll-like receptor as an acute phase response to infection. As a result, it acts as a potent bacteriostatic reagent by sequestering iron (7). Moreover, Lipocalin-2 can alter the invasive and metastatic behavior of Ras-transformed breast cancer cells in vitro and in vivo by reversing epithelial to mesenchymal transition inducing activity of Ras, through restoration of E-cadherin expression, via effects on the Ras-MAPK signaling pathway (8).

1. Flower, D.R. et al. (1994) FEBS Lett. 354:7.
2. Kjeldsen, L. et al. (1993) J. Biol. Chem. 268:10426.
3. Kjeldsen L, et al. (2000) Biochim Biophys Acta. 1482:272.
4. Devireddy, L.R. et al. (2001) Science 293:829.
5. Yang, M.B. et al. (2002) Mol. Cell. 10:1045.
6. Goetz, D.H. et al. (2002) Mol. Cell 10:1033.
7. Flo, T.H. et al. (2004) Nature 432:917.
8. Hanai, J. et al. (2005) J. Biol. Chem. 280:13641.