• 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 the ability of the immobilized protein to support the adhesion of HT1080 human fibrosarcoma cells.

  The ED₅₀ for this effect is 0.7-2.8 μg/mL.

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

• Source

  Chinese Hamster Ovary cell line, CHO-derived Gln826-Ala1816, with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Gln826 predicted, sequencing might be blocked, no result obtained

• Structure / Form

  Monomer

• Predicted Molecular Mass

  111 kDa

• SDS-PAGE

  110-120 kDa, reducing conditions

Background: Laminin alpha 4

The alpha 4 chain of laminin (LAMA4) is a secreted ~210 kDa glycoprotein that contributes to the formation of LN411 (laminin-8, subunits alpha 4 beta 1 gamma 1), LN421 (laminin-9, subunits alpha 4 beta 2 gamma 1), and LN423 (laminin-14, subunits alpha 4 beta 2 gamma 3) (1-4). Laminin alpha,  beta  and  gamma  subunits interact via alpha -helical domains to create cruciform, disulfide-linked, coiled-coil laminin heterotrimers (1, 2). LAMA4 is mainly expressed in mesodermal tissues, and is produced by endothelium, cardiac and skeletal muscle fibers, lung mesenchymal cells, pre-adipocytes, kidney mesangial cells, peripheral nerves and neutrophils (3-8). It is found in the subendothelium in muscle, brain, and bone marrow, and in heart, skin, and the perineurium of peripheral nerves (3-7, 9, 10). The human LAMA4 cDNA encodes 1823 amino acids (aa), including a 24 aa signal sequence and a 1799 aa mature protein that contains three EGF-like repeats (aa 82-240) followed by five coiled-coil regions (aa 320-806) and five globular, laminin G-like (LG) domains (aa 833-1820). Potential isoforms of 1816 aa and 1791 aa are lacking sequences following the EGF-like repeats. A protease-sensitive region between LG3 and LG4 produces a processed ~180 kDa form that is detected in vivo (9, 10). Within the LG region, human and mouse LAMA4 share 91% aa sequence identity. LAMA4 LG domains serve as Ca⁺⁺-mediated receptors for integrins such as alpha v beta 3 and alpha 3 beta 1 (mainly at LG2), fibulin-1 and -2 (multiple LG), and heparan sulfate proteoglycans such as syndecans 2 and 4 (mainly at LG4) (8-12). Deletion of LAMA4 in mice results in misalignment of pre- and post-synaptic membranes at neuromuscular junctions, faulty nerve myelination, chronic kidney disease, deficient neutrophil extravasation, and microvessel instability, which causes cardiomyopathy and circulatory dysfunctions (5-8, 12-14). These results show the importance of LAMA4-containing laminins in normal synapse maturation and blood vessel maturation.

• References:

1. Tzu, J. and M.P. Marinkovich (2008) Int. J. Biochem. Cell Biol. 40:199.

2. Durbeej, M. (2010) Cell Tiss. Res. 339:259.

3. Liu, J. et al. (1996) Matrix Biol. 15:433.

4. Iivanainen, A. et al. (1997) J. Biol. Chem. 272:27862.

5. Patton, B.L. et al. (2001) Nat. Neurosci. 4:597.

6. Wallquist, W. et al. (2005) J. Neurosci. 25:3692.

7. Abrass, C.K. et al. (2010) Am. J. Pathol. 176:839.

8. Wondimu, Z. et al. (2004) Blood 104:1859.

9. Matsuura, H. et al. (2004) J. Invest. Dermatol. 122:614.

10. Talts, J.F. et al. (2000) J. Biol. Chem. 275:35192.

11. Gonzalez, A.M. et al. (2002) Proc. Natl. Acad. Sci. USA 99:16075.

12. DeHahn, K.C. et al. (2004) Exp. Cell Res. 294:281.

13. Thyboll, J. et al. (2002) Mol. Cell Biol. 22:1194.

14. Wang, J. et al. (2006) J. Biol. Chem. 281:213.

• Entrez Gene IDs:

  3910 (Human); 16775 (Mouse); 309816 (Rat)

• Alternate Names:

  DKFZp686D23145; LAMA3LAMA4*-1; LAMA4; laminin alpha 4 chain; Laminin alpha 4; laminin subunit alpha-4; laminin, alpha 4; Laminin-14 subunit alpha; Laminin-8 subunit alpha; Laminin-9 subunit alpha