Galectin-3 is a member of the galectin family. The protein is composed of three domains: a small amino-terminal domain, a carboxyl-terminal carbohydrate recognition domain (CRD) and amino-terminal domain containing repeating elements. Galectin-3 is normally distributed in epithelia of many organs and various inflammatory cells, including macrophages, as well as dendritic cells and Kupffer cells. The expression of this lectin is up-regulated during inflammation, cell proliferation, cell differentiation and through trans-activation by viral proteins. The expression is also affected by neoplastic transformation: up-regulated in certain types of lymphomas and thyroid carcinoma, while down-regulated in other types of malignancies, such as colon, breast, ovarian and uterine carcinomas. Galectin-3 has been shown to function through both intracellular and extracellular actions. Related to its intracellular functions, galectin-3 has been identified as a component of heterogeneous nuclear ribonuclear protein (hnRNP), a factor in pre-mRNA splicing, and has been found to control cell cycle and prevent T cell apoptosis. On the other hand, this protein has also been demonstrated to function as extracellular molecule in activating various types of cells, including monocytes/macrophages, mast cells, neutrophils and lymphocytes. Galectin-3 has been shown to mediate cell-cell and cell-extracellular matrix interactions.Synonyms: 35 kDa lectin, CBP35, Carbohydrate-binding protein 35, GAL3, GALBP, Galactose-specific lectin 3, IgE-binding protein, L-31, L-34 galactoside-binding lectin, Laminin-binding protein, Lectin L-29, Lgals3, Mac-2