Galectin 9 Short Variant (human, recombinant)

Galectin 9 is a β-galactoside-binding protein encoded by the LGALS9 gene and a member of the galectin family.¹ 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.^1,2 The non-identical CRDs are responsible for binding to different types of saccharide ligands with the N-terminal CRD (NCRD) preferring more complex glycoconjugates.¹ Galectin 9 is localized to the cytosol, nucleus, and extracellular matrix and is expressed primarily in immune-related tissues and cells.³ 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.⁴ 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 CD44.⁵ The short variant of galectin 9 acts as an eosinophil chemoattractant.⁶ It also activates CD4⁺ T cell populations and induces naïve T cells to acquire a central memory T cell (T_CM) phenotype.⁷ Galectin 9 was originally identified as a tumor antigen in patients with Hodgkin’s disease.¹ 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.³ 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 γ (IFN-γ) in synovial fibroblasts isolated from patients with rheumatoid arthritis.⁸ 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.

WARNING This product is not for human or veterinary use.

1. Nagae, M., Nishi, N., Murata, T., et al. Crystal structure of the galectin-9 N-terminal carbohydrate recognition domain from Mus musculus reveals the basic mechanism of carbohydrate recognition. The Journal of Biological Chemisty 281(47), 35884-35893 (2006).

2. Chabot, S., Kashio, Y., Seki, M., et al. Regulation of galectin-9 expression and release in Jurkat T cell line cells. Glycobiology 12(2), 111-118 (2002).

3. Heusschen, R., Griffioen, A.W., and Thijssen, V.L. Galectin-9 in tumor biology: A jack of multiple trades. Biochim. Biophys. Acta 1836(1), 177-185 (2013).

4. Wolf, Y., Anderson, A.C., and Kuchroo, V.K. TIM3 comes of age as an inhibitory receptor. Nat. Rev. Immunol. 20(3), 173-185 (2020).

5. John, S., and Mishra, R. Galectin-9: From cell biology to complex disease dynamics. J. Biosci. 41(3), 507-534 (2016).

6. Sato, M., Nishi, N., Shoji, H., et al. Functional analysis of the carbohydrate recognition domains and a linker peptide of galectin-9 as to eosinophil chemoattractant activity. Glycobiology 12(3), 191-197 (2002).

7. Gooden, M.J.M., Wiersma, V.R., Samplonius, D.F., et al. Galectin-9 activates and expands human T-helper 1 cells. PLoS One 8(5), e65616 (2013).

8. Pearson, M.J., Bik, M.A., Ospelt, C., et al. Endogenous galectin-9 suppresses apoptosis in human rheumatoid arthritis synovial fibroblasts. Sci. Rep. 8(1), 12887 (2018).