• Purity

  >95%, 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 the ability of the immobilized protein to support the adhesion of U?87 MG human glioblastoma/astrocytoma cells. The typical ED    ₅₀ for this effect is 0.9-3.6 μg/mL after 1 hour incubation at 37 °C.

  
  

  Optimal dilutions should be determined by each laboratory for each application.

• Source

  Chinese Hamster Ovary cell line, CHO-derived Ala1260-Pro2045, with an N-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  His

• Structure / Form

  Monomer

• Predicted Molecular Mass

  83.5 kDa

• SDS-PAGE

  100-110 kDa, reducing conditions

Background: Agrin

Agrin is a 400?600 kDa heparan sulfate proteoglycan component of the extracellular matrix. The N-terminal half of human Agrin, which mediates ECM interactions, contains a Laminin-binding NtA domain, nine Kazal-type protease inhibitor domains, two Laminin EGF-like domains, and one SEA domain. The C?terminal half contains four EGF-like repeats and three Laminin globular G domains. Rat Agrin lacks the NtA domain, and mouse and chick Agrin include the NtA domain only by the use of an alternate promoter. Additional isoforms are generated by alternate splicing at sites Y and Z in the C?terminal half of rat Agrin (known as A and B, respectively in chick). Agrin isoforms that contain an insert at site Z (Z+ forms) are known as neural Agrin and are selectively produced by motoneurons. Other isoforms are known as muscle Agrin and are additionally expressed in non-neuronal tissues, particularly in basement membranes of the lung and kidney (1-3). This recombinant protein consists of the C?terminal half of human Agrin corresponding to the Z- isoform of rat Agrin. It shares 60%, 78%, and 80% amino acid sequence identity with comparable regions of chick, mouse, and rat Agrin, respectively. The C?terminal half of Z- and Z+ Agrin binds to alpha ?Dystroglycan and mediates adhesion between motoneurons and myotubes at the neuromuscular junction (NMJ) (4-6). In contrast, only Z+ Agrin is effective at inducing clustering of the postsynaptic Acetylcholine Receptor (AChR) and presynaptic motoneuron differentiation (7, 8). Agrin-induced AChR clustering requires a myotube receptor complex that contains alpha ?Dystroglycan, MuSK, and LRP4 (4, 9-11). Agrin exhibits many functions in addition to NMJ development. It is enriched in senile Alzheimer's disease plaques where it binds the A beta (1?40) peptide and promotes amyloid fibril formation (12). It regulates neuronal excitability by binding and inhibiting the alpha 3 subunit of the neuronal Na/K ATPase (13). It functions as an epithelial cell attachment receptor for HIV-1 through interactions with the gp41 coat protein (14). During T cell activation, Agrin contributes to formation of the immunological synapse and regulates the threshold of T cell activation (15).

• References:

1. Jury, E.C. and P.S. Kabouridis (2010) Arthritis Res. Ther. 12:205.

2. Bezakova, G. and M.A. Ruegg (2003) Nat. Rev. Mol. Cell Biol. 4:295.

3. Groffen, A.J.A. et al. (1998) Eur. J. Biochem. 254:123.

4. Gee, S.H. et al. (1994) Cell 77:675.

5. Sugiyama, J. et al. (1994) Neuron 13:103.

6. Gesemann, M. et al. (1998) J. Biol. Chem. 273:600.

7. Burgess, R.W. et al. (1999) Neuron 23:33.

8. Ferns, M.J. et al. (1993) Neuron 11:491.

9. Glass, D.J. et al. (1996) Cell 85:513.

10. Kim, N. et al. (2008) Cell 135:334.

11. Zhang, B. et al. (2008) Neuron 60:285.

12. Cotman, S.L. et al. (2000) Mol. Cell. Neurosci. 15:183.

13. Hilgenberg, L.G.W. et al. (2006) Cell 125:359.

14. Alfsen, A. et al. (2005) Mol. Biol. Cell 16:4267.

15. Khan, A.A. et al. (2001) Science 292:1681.

• Entrez Gene IDs:

  375790 (Human); 25592 (Rat)

• Alternate Names:

  agrin proteoglycan; Agrin; AGRN