• Purity

  >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability of the immobilized protein to support the adhesion of Jurkat human acute T cell leukemia cells. The ED    ₅₀ for this effect is 0.75-4.5 μg/mL.    
   

• Source

  Human embryonic kidney cell, HEK293-derived Met1-Thr323

• Accession #

• N-terminal Sequence    
  Analysis

  Met1 & Phe3    
   

• Predicted Molecular Mass

  36 kDa

• SDS-PAGE

  42-51 kDa, reducing conditions    
   

Background: Galectin-9

Galectins comprise a family of multifunctional carbohydrate-binding proteins with specificity for N-acetyl-lactosamine-containing glycoproteins. At least 14 mammalian Galectins share structural similarities in their carbohydrate recognition domains (CRD), forming three groups: prototype (one CRD), tandem-repeat (two CRDs), and chimeric (one CRD, unique N-terminus) (1, 2). Full length Galectin-9 is a widely expressed 39 kDa tandem-repeat Galectin that contains two CRDs connected by a linker region (3). Progressive deletion within the linker region generates a 36 kDa isoform, also known as Ecalectin or UAT, as well as a 35 kDa isoform (4). This recombinant protein corresponds to the Ecalectin isoform of human Galectin-9 and shares 70% and 73% aa sequence identity with the corresponding regions of mouse and rat Galectin-9, respectively. Galectin-9 exhibits a wide range of activities. All three isoforms function as eosinophil chemoattractants (5, 6). This activity is destroyed by thrombin-mediated cleavage within the linker region of the long isoform, although the Ecalectin isoform is resistant to thrombin (7). Galectin-9 binds to carbohydrate moieties of IgE, thereby preventing immune complex formation, mast cell degranulation, and asthmatic and cutaneous anaphylaxis reactions (8). Independent of its lectin properties, Galectin-9 induces the maturation of dendritic cells which promote Th1 polarization (9). Galectin-9 induces cellular apoptosis in part by direct binding to TIM-3 (10, 11). Its interaction with TIM-3 inhibits Th1 cell and CD8  ⁺ cytotoxic T cell responses and also promotes regulatory T cell differentiation and activity (11, 12). Galectin-9 suppresses tumor cell metastasis by interfering with the associations between hyaluronic acid and CD44 and between VCAM-1 and Integrin alpha 4 beta 1 (13). The Ecalectin isoform (UAT; urate transporter) can also be expressed as an integral membrane protein and mediate the cellular efflux of urate (14).

• References:

1. Heusschen, R. et al. (2013) Biochim. Biophys. Acta 1836:177.

2. Elola, M. T. et al. (2007) Cell. Mol. Life Sci. 64:1679.

3. Tureci, O. et al. (1997) J. Biol. Chem. 272:6416.

4. Chabot, S. et al. (2002) Glycobiology 12:111.

5. Matsumoto, R. et al. (2002) J. Immunol. 168:1961.

6. Sato, M. et al. (2002) Glycobiology 12:191.

7. Nishi, N. et al. (2006) Glycobiology 16:15C.

8. Niki, T. et al. (2009) J. Biol. Chem. 284:32344.

9. Dai, S.-Y. et al. (2005) J. Immunol. 175:2974.

10. Seki, M. et al. (2007) Arthritis Rheum. 56:3968.

11. Zhu, C. et al. (2005) Nat. Immunol. 6:1245.

12. Sehrawat, S. et al. (2010) PloS Pathogens 6:e1000882.

13. Nobumoto, A. et al. (2008) Glycobiology 18:735.

14. Leal-Pinto, E. et al. (2002) Am. J. Physiol. Renal Physiol. 283:F150.

• Entrez Gene IDs:

  3965 (Human); 16859 (Mouse)

• Alternate Names:

  Ecalectin; GAL9; gal-9; galectin 9; Galectin9; Galectin-9; HUAT; lectin, galactoside-binding, soluble, 9; LGALS9; LGALS9A; MGC117375; MGC125973; MGC125974; Tumor antigen HOM-HD-21; urate transporter/channel protein