• Purity

  >95%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

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

• Activity

  Measured by its binding ability in a functional ELISA. When Recombinant Human Endosialin/CD248 is immobilized at 2 μg/mL (100 μL/well), the concentration of Recombinant Human Galectin‑3BP/MAC‑2BP (Catalog # ) that produces 50% of the optimal binding response is approximately 0.08-0.4 μg/mL.

• Source

  Mouse myeloma cell line, NS0-derived Gln18-Arg685, with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Gln18 predicted: No results obtained, sequencing might be blocked

• Predicted Molecular Mass

  72 kDa

• SDS-PAGE

  110-150 kDa, reducing conditions

Background: Endosialin/CD248

Endosialin, also known as TEM1 (tumor endothelial marker 1) and designated CD248, is a 165‑175 kDa type I transmembrane O‑glycosylated protein that is expressed on activated perivascular and stromal cells in embyronic and tumor neovasculature, but down‑regulated in quiescent vasculature (1‑4). The human Endosialin cDNA encodes 757 amino acids (aa) including a 17 aa signal sequence, a 670 aa extracellular domain (ECD) with one C‑type lectin, one Sushi, one EGF‑like domain and a mucin-like stalk, a transmembrane sequence, and a short (49 aa) cytoplasmic domain with three potential phosphorylation sites and a PDZ binding motif (2, 3). Within the ECD, human Endosialin shares 76% and 74% aa sequence identity with mouse and rat Endosialin, respectively. Endosialin regulates pericyte proliferation, migration, and adhesion to endothelial cell‑deposited fibronectin and collagens I and IV in the extracellular matrix (3‑7). It binds Galectin‑3/MAC‑2BP, mediating a repulsive signal thought to guide tumor cell migration (5). In blood vessel development, it promotes endothelial cell apoptosis and pruning of unwanted capillaries (6). In humans, it is up‑regulated on mesenchymal stem cells, naïve CD8  ⁺ T cells, and leukocytes that express markers of endothelial and dendritic lineages (3, 8). It is dynamically expressed on lymphoid tissue stromal cells and is required for lymph node, spleen, and thymus remodeling during immune responses (8‑11). Its expression correlates with suppressed proliferation of human naïve CD8  ⁺ T cells, and with aggressiveness of some tumors (8, 12, 13). Endosialin expression is up‑regulated   in vitro by high cell density and hypoxia (3, 14). Inflammatory conditions such as rheumatoid and psoriatic arthritis and IgA nephropathy can cause expression in stroma that do not normally express Endosialin (3).

• References:

1. Rettig, W.J. et al. (1992) Proc. Natl. Acad. Sci. USA 89:10832.

2. Christian, S. et al. (2001) J. Biol. Chem. 276:7408.

3. Valdez, Y. et al. (2012) Curr. Drug Targets 13:432.

4. MacFadyen, J.R. et al. (2005) FEBS Lett. 579:2569.

5. Becker, R. et al. (2008/) FASEB J. 22:3059.

6. Simonavicius, N. et al. (2012) Blood 120:1516.

7. Tomkowicz, B. et al. (2010) Cancer Biol. Ther. 9:908.

8. Hardie, D.L. et al. (2011) Immunology 133:288.

9. Lax, S. et al. (2007) FEBS Lett. 581:3551.

10. Lax, S. et al. (2010) Eur. J. Immunol. 40:1884.

11. Lax, S. et al. (2012) FEBS Open Bio 2:187.

12. Nanda, A. et al. (2006) Proc. Natl. Acad. Sci. USA 103:3351.

13. Maia, M. et al. (2011) BMC Cancer 11:162.

14. Ohradanova, A. et al. (2008) Br. J. Cancer 99:1348.

• Entrez Gene IDs:

  57124 (Human); 70445 (Mouse); 293669 (Rat)

• Alternate Names:

  2610111G01Rik; CD164 sialomucin-like 1; CD164L1; CD248 antigen; CD248 antigen, endosialin; CD248 molecule, endosialin; CD248; Endosialin; MGC119479; TEM1; TEM1MGC119478; Tumor endothelial marker 1