Lipocalin-2 (LCN2, also known as siderocalin, uterocalin, oncogene 24p3, and neutrophil gelatinase-associated lipocalin) is expressed in renal, endothelial, liver, smooth muscle cells, cardiomyocytes, in various populations of immune cells and dendritic cells. Roles ascribed to LCN2, include chemotactic and bacteriostatic effects, and iron trafficking. LCN2 can also act as a growth factor. It plays an key role in the pathophysiology of renal and cardiovascular diseases, and is involved in various deleterious processes, such as inflammation and fibrosis. It is used as a renal injury biomarker. This subgroup belongs to the lipocalin/cytosolic fatty-acid binding protein family which have a large beta-barrel ligand-binding cavity. Lipocalins are mainly low molecular weight extracellular proteins that bind principally small hydrophobic ligands, and form covalent or non-covalent complexes with soluble macromolecules, as well as membrane bound-receptors. They participate in processes such as ligand transport, modulation of cell growth and metabolism, regulation of immune response, smell reception, tissue development and animal behavior. Cytosolic fatty-acid binding proteins, also bind hydrophobic ligands in a non-covalent, reversible manner, and have been implicated in intracellular uptake, transport and storage of hydrophobic ligands, regulation of lipid metabolism and sequestration of excess toxic fatty acids, as well as in signaling, gene expression, inflammation, cell growth and proliferation, and cancer development.
Comment:hydrophobic cavity binds different hydrophobic ligands; ligands are bound within the beta-barrel in a central internal water-filled cavity lined with polar and hydrophobic amino acids
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