• Purity

  >90%, 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 ability to inhibit the adhesion of J45.01 human acute lymphoblastic leukemia T lymphocytes on immobilized JAM-2 (VE-JAM)/Fc Chimera. When 0.2 μg/mL (100 μL/well) of rhJAM-B/Fc Chimera is immobilized on goat anti-human IgG Fc Chimera antibody coated wells, the ED    ₅₀ for this effect is 0.1-0.5 μg/mL in the presence of 1 x 10    ⁵ cells/well.

• Source

  Mouse myeloma cell line, NS0-derived

  Human JAM-C Val32 - Asn241 (Ala149Pro) Accession # Q9BX67	IEGRMD	Human IgG1 (Pro100 - Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Val32

• Structure / Form

  Disulfide-linked homodimer

• Predicted Molecular Mass

  50 kDa (monomer)

• SDS-PAGE

  60-65 kDa, reducing conditions

Background: JAM-C

The family of juctional adhesion molecules (JAM), comprising at least three members, are type I transmembrane receptors belonging to the immunoglobulin (Ig) superfamily (1, 2). These proteins are localized in the tight junctions between endothelial cells or epithelial cells. Some family members are also found on blood leukocytes and platelets. Human JAM-C cDNA predicts a 310 amino acid (aa) residue precursor protein with a putative 31 aa signal peptide, a 210 aa extracellular region containing two Ig domains, a 23 aa transmembrane domain and a 46 aa cytoplasmic domain containing a PDZ-binding motif and a PKC phosphorylation site (3, 4). Human JAM-C shares 86% aa sequence identity with its mouse homologue. It also shares approximately 36% and 32% aa sequence homology with human JAM-B and JAM-A, respectively (3 - 5). Human JAM-C shows widespread tissue expression and the highest levels are found in the placenta, brain, kidney and heart. JAM-C is expressed on endothelial cells of high endothelial venules in human tonsil. It is also expressed on platelets, T-cells and NK cells (3 - 5). Unlike other JAM family members, JAM-C forms only weak homotypic interactions. JAM-C binds to JAM-B to facilitate the interactions between JAM-B and the integrin alpha4beta1 (6). This heterotypic interaction between leukocyte JAM-C and endothelial JAM-B may play a role in regulating leukocyte transmigration (5). On platelets, JAM-C is a counter-receptor for the leukocyte integrin Mac-1(CD11b/CD18) (7). JAM-C has also been identified as a strong candidate gene for hypoplastic left heart syndrome (8).

The nomenclature used for the JAM family proteins is confusing. VE-JAM has been referred to in the literature variously as JAM-B or JAM-C. Until further clarification, R&D Systems has adopted the nomenclature where both mouse and human VE-JAM are referred to as JAM-B. Under this system, JAM-C refers to the protein encoded by the gene localized to human chromosome 11.

• References:

1. Chavakis, T. et al. (2003) Thromb. Haemost. 89:13.

2. Aurand-Lions, M. et al. (2001) Blood 98:3699.

3. Arrate, M.P. et al. (2001) J. Biol. Chem. 276:45826.

4. Liang, T. et al. (2002) J. Immunol. 168:1618.

5. Johnson-Leger, C. et al. (2002) Blood 100:25793.

6. Cunningham, A. et al. (2002) J Biol. Chem. 277:27589.

7. Santoso, S. et al. (2002) J. Exp. Med. 196:679.

8. Phillips, H.M. et al. (2002) Genomics 79:475.

• Long Name:

  Junctional Adhesion Molecule C

• Entrez Gene IDs:

  83700 (Human); 83964 (Mouse)

• Alternate Names:

  CD323; JAM-2; JAM3; JAMC; JAM-C; JAM-CFLJ14529; junctional adhesion molecule 3JAM-3; junctional adhesion molecule C