• Purity

  >90%, 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 binding ability in a functional ELISA. Biotinylated recombinant rat NLGN-1v2 immobilized on a streptavidin-coated plate at 1 μg/mL    
  (100 μL/well) can bind Recombinant Human Neurexin 1 beta /NXRN1b Fc Chimera with an apparent K    _d <4 nM.  

• Source

  Mouse myeloma cell line, NS0-derived

  Human Neurexin 1 beta (Ala51-Ser363) Accession # NP_620072	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Ala51

• Structure / Form

  Disulfide-linked homodimer

• Predicted Molecular Mass

  59.9 kDa (monomer)

• SDS-PAGE

  85-95 kDa, reducing conditions

Background: Neurexin 1 beta/NXRN1b

The alpha and beta forms of Neurexins 1-3 are transmembrane neuronal glycoproteins which are transcribed from each of three NRXN genes that utilize alternate promoters. Like other Neurexins, the extracellular domain (ECD) of Neurexin 1 alpha contains six LNS domains interspersed with three EGF-like domains, while that of Neurexin 1 beta contains only the sixth LNS domain and no EGF-like domains (1 - 3). Mature human Neurexin 1 beta is a 70 kDa glycosylated protein with a 313 amino acid (aa) ECD and a 56 aa cytoplasmic domain that contains a motif for binding PDZ scaffolding proteins (2, 4, 5). Within comparable regions of the ECD, human Neurexin 1 beta shares 99% aa sequence identity with mouse and rat Neurexin 1 beta. It shares 42% and 68% aa sequence identity with the ECDs of human Neurexin 2 beta and 3 beta, respectively. Neurexin 1 beta isoforms are differentiated by a 30 aa insertion at alternative splice site 4 (SS4), numbered according to splice sites in the longer alpha Neurexins (4, 5). This recombinant protein does not include the SS4 insertion. Neurexin 1 beta is expressed presynaptically at neuronal contacts and interacts with postsynaptic Neuroligins 1-4. The presence of the SS4 insertion significantly weakens this interaction, particularly with Neuroligins 1 and 4 (6-12). Binding affinity is also dependent on the splicing pattern of the Neuroligin (7, 10, 11). Within the presynaptic terminal, Neurexin 1 beta is required for the recruitment of scaffolding proteins and synaptic vesicles (13). Its interaction with Neuroligins 1, 3, and 4 induces the development of glutamatergic postsynaptic terminals containing NMDA receptors, while its interaction with Neuroligin 2 promotes GABAergic postsynaptic development (10, 12, 14, 15). The presence of the SS4 insertion reduces the ability of Neurexin 1 beta to promote glutamatergic contacts but is required for the development of Neuroligin 2/GABAergic contact development (10, 12).

• References:

1. Craig, A.M. and Y. Kang (2007) Curr. Opin. Neurobiol. 17:43.

2. Lise, M.-F. and A. El-Husseini (2006) Cell. Mol. Life Sci. 63:1833.

3. Dean, C. and T. Dresbach (2006) Trends Neurosci. 29:21.

4. Rowen, L. et al. (2002) Genomics 79:587.

5. Ushkaryov, Y.A. et al. (1992) Science 257:50.

6. Ichtchenko, K. et al. (1995) Cell 81:435.

7. Comoletti, D. et al. (2006) Biochemistry 45:12816.

8. Ichtchenko, K. et al. (1996) J. Biol. Chem. 271:2676.

9. Arac, D. et al. (2007) Neuron 56:992.

10. Chih, B. et al. (2006) Neuron 51:171.

11. Boucard, A.A. et al. (2005) Neuron 48:229.

12. Graf, E.R. et al. (2006) J. Neurosci. 26:4256.

13. Dean, C. et al. (2003) Nat. Neurosci. 7:708.

14. Nam, C.I. and L. Chen (2005) Proc. Natl. Acad. Sci. 102:6137.

15. Graf, E.R. et al. (2004) Cell 119:1013.

• Entrez Gene IDs:

  9378 (Human); 18189 (Mouse); 60391 (Rat)

• Alternate Names:

  Neurexin 1 beta; NXR1B; NXRN1b