• Purity

  >90%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.

• Endotoxin Level

  <0.01 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its binding ability in a functional ELISA. When Recombinant Human Plexin C1 (Catalog # ) is coated at 5 μg/mL, Recombinant Human Semaphorin 7A Fc Chimera binds with an apparent K    _d <5 nM.  

• Source

  Mouse myeloma cell line, NS0-derived

  Human Semaphorin 7A (His47-Ala648) Accession # O75326	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  His47

• Structure / Form

  Disulfide-linked homodimer    
   

• Predicted Molecular Mass

  94.8 kDa (monomer)

• SDS-PAGE

  100-105 kDa, reducing conditions

Background: Semaphorin 7A

Semaphorin 7A (Sema7A, designated CD108, previously Sema K1 or Sema L), is an ~80 kDa membrane-anchored glycoprotein that is a member of the Semaphorin family of axon guidance molecules (1 ‑ 4). On human erythrocytes, it is the John Milton Hagen (JMH) blood group antigen (4). Sema7A is the only known Class 7 or glycophosphatidylinositol (GPI)-linked semaphorin; its expression is concentrated in the brain, spleen and thymus (1 ‑ 5). Human Sema7A cDNA encodes a 44 amino acid (aa) signal sequence, a 604 aa extracellular domain (ECD) including Sema and C2‑type Ig-like domains, and an 18 aa propeptide/GPI membrane anchor signal sequence. Mature human Sema7A shares 89%, 89%, 88%, 86% and 90% aa identity with mouse, rat, canine, bovine and equine Sema7A, respectively. The Sema7A sema domain contains an RGD integrin interaction motif (4). Although it binds plexin-C1 in vitro and may be coexpressed with it, many of its activities depend on interaction with beta 1 integrins such as alpha 1 beta 1 (6 ‑ 10). Sema7A signaling through the two receptors may cause opposing effects (8). Sema7A is an immune semaphorin, with expression and activity on CD4⁺CD8⁺ thymocytes, activated T cells, macrophages and microglia (2, 9 ‑ 12). T cell Sema7A interacts with monocytic cells, stimulating their chemotaxis, production of pro-inflammatory cytokines, and dendritic differentiation (5, 6). However, on the T cells themselves, Sema7A downregulates TCR signaling by promoting TCR internalization, modulating T cell responses (9). In lung macrophages, Sema7A is induced by TGF-beta and participates in TGF-beta -induced lung fibrosis (12). Sema7A is also expressed on pre-osteoblasts and osteoclasts, where it promotes migration and fusion, respectively; on keratinocytes, where it promotes melanocyte spreading and dendricity; and on some neurons, for example, promoting axon outgrowth in the developing olfactory tract (8, 10, 13). 

• References:

1. Yazdani, U. and J.R. Terman (2006) Genome Biol. 7:211.

2. Kikutani, H. et al. (2007) Adv. Immunol. 93:121.

3. Sato, Y. and Takahashi H. (1998) Biochim. Biophys. Acta. 1443:419.

4. Yamada, A. et al. (1999) J. Immunol. 162:4094.

5. Holmes, S. et al. (2002) Scand. J. Immunol. 56:270.

6. Suzuki, K. et al. (2007) Nature 446:680.

7. Pasterkamp, R.J. et al. (2007) BMC Dev. Biol. 7:98.

8. Scott, G.A. et al. (2007) J. Invest. Dermatol. 128:151.

9. Czopik, A.K. et al. (2006) Immunity 24:591.

10. Pasterkamp, R.J. et al. (2003) Nature 424:398.

11. Mine, T. et al. (2000) Tissue Antigens 55:429.

12. Kang, H.-R. et al. (2007) J. Exp. Med. 204:1083.

13. Delorme, G. et al. (2005) Biol. Cell 97:589.

• Entrez Gene IDs:

  8482 (Human); 20361 (Mouse)

• Alternate Names:

  CD108 antigen; CD108; CD108MGC126696; CDw108; H-SEMA-K1; H-Sema-L; JMH blood group antigen; JMH; John-Milton-Hargen human blood group Ag; MGC126692; sema domain, immunoglobulin domain (Ig), and GPI membrane anchor, (semaphorin)7A (JMH blood group); sema domain, immunoglobulin domain (Ig), and GPI membrane anchor, (semaphorin)7A; sema domain, immunoglobulin domain (Ig), and GPI membrane anchor, 7A; Sema K1; Sema L; Sema7A; SEMAK1; SEMAL; SEMALJohn Milton Hagen blood group H-Sema K1; Semaphorin 7A; semaphorin 7A, GPI membrane anchor (John Milton Hagen blood group); semaphorin K1; semaphorin L; semaphorin-7A; semaphorin-K1; semaphorin-L