Galectin 9 Short Variant (human, recombinant)

Galectin 9 is a B-galactoside-binding protein encoded by the LGALS9 gene and a member of the galectin family.{56051} It contains two non-identical carbohydrate recognition domains (CRDs) joined by a peptide linker, the length of which depends on alternative splicing of the LGALS9 gene, which produces a short, medium, or long variant of the protein.{56051,56052} The non-identical CRDs are responsible for binding to different types of saccharide ligands with the N-terminal CRD (NCRD) preferring more complex glycoconjugates.{56051} Galectin 9 is localized to the cytosol, nucleus, and extracellular matrix and is expressed primarily in immune-related tissues and cells.{56053} When expressed on immune or tumor cells, galectin 9 binds to glycosylated sites on the immunoregulatory protein TIM-3 and activates signaling that impairs immune synapse formation leading to T cell anergy or apoptosis.{55230} It also binds to the transmembrane glycoprotein CD44 on osteoblasts, leading to their proliferation, and it has a role in cell adhesion by preventing hyaluronic acid from binding to CD44.{56054} The short variant of galectin 9 acts as an eosinophil chemoattractant.{56055} It also activates CD4+ T cell populations and induces naïve T cells to acquire a central memory T cell (TCM) phenotype.{56056} Galectin 9 was originally identified as a tumor antigen in patients with Hodgkin’s disease.{56051} It is expressed to a lower extent in tumor cells compared with non-tumor cells but is increased in leukemia and colon cancer cell lines.{56053} Increased expression of the short variant of galectin 9 inhibits or enhances adhesion in breast or colon cancer cell lines, respectively. The expression of the short variant of galectin 9 is increased by interferon y (IFN-y) in synovial fibroblasts isolated from patients with rheumatoid arthritis.{56057} Cayman's Galectin 9 Short Variant (human, recombinant) protein is a disulfide-linked homodimer. The reduced monomer, comprised of galectin 9 (amino acids 2-323) fused to human IgG1 Fc at its N-terminus, consists of 554 amino acids and has a calculated molecular weight of 61.8 kDa.