• Purity

  >95%, 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 the ability of the immobilized protein to support the adhesion of CHO Chinese hamster ovary cells transfected with ICAM-1. The ED    ₅₀ for this effect is 0.3-1.2 μg/mL.

• Source

  Chinese Hamster Ovary cell line, CHO-derived

  Mouse Integrin alpha L (Tyr24-Glu1084) Accession # P24063	His-Pro	GGGSGGGS	Acidic Tail	6-His tag
  Mouse Integrin beta 2 (Gln24-Asn702) Accession # P11835	His-Pro	GGGSGGGS	Basic Tail
  N-terminus			C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Tyr24 (Integrin  alpha L) & Gln24 predicted: No results obtained, sequencing might be blocked (Integrin beta 2)

• Structure / Form

  Noncovalently-linked heterodimer

• Predicted Molecular Mass

  126 kDa (Integrin alpha L) & 83 kDa (Integrin beta 2)

• SDS-PAGE

  95-105 kDa & 155-175 kDa, reducing conditions

Background: Integrin alpha L beta 2

Integrin alpha L beta 2, also called LFA-1, is one of three beta 2 integrin adhesion proteins. The non?covalent heterodimer of 180 kDa alpha L/CD11a and 95 kDa beta 2/CD18 integrin subunits is expressed on virtually all leukocytes (1?3). The ligand binding site of LFA-1 is in the N-terminal head region, formed by an interaction of the vWFA
(I, I?like) domains from each subunit, and the alpha L beta-propeller structure (3?5). The alpha L subunit contains domains termed thigh, calf-1 and calf-2, while the beta 2 subunit contains a PSI (plexin-semaphorin-integrin) region and four cysteine-rich I-EGF folds (3). Each subunit has a transmembrane sequence and a short cytoplasmic tail connected to the cytoskeleton. Upon activation by “inside?out” signaling, clustering, or Mg²⁺ or Mn²⁺ binding to metal ion-dependent adhesion sites (MIDAS) within the vWFA domains, the molecule unfolds from its inactive, “closed” conformation to expose ligand binding sites (3?7). Active alpha L beta 2 binds ICAM-1/CD54, ICAM-2, ICAM-3 and JAM-A (1, 8?10). The adhesion stabilizes interactions between T cells and antigen-presenting cells, decreases the T cell activation threshold, and facilitates transendothelial migration of neutrophils and other leukocytes to sites of inflammation (10?13). Blockade of LFA-1 may inhibit graft vs. host disease and transplant rejection (14). A constitutively active construct severely impairs immune responses, demonstrating that both activation and de-activation are important (12). Mutations of beta 2, especially in the vWFA domain, cause leukocyte adhesion deficiency (LAD-1) and susceptibility to bacterial infections (15). The 1065 amino acid (aa) mouse alpha L/CD11b ECD shares 87% aa sequence identity with rat, and 70?74% with human, equine, bovine, porcine, and canine  alpha L ECD. Potential mouse alpha L isoforms of 626 and 601 aa have alternate N- or C-termini, respectively. The 679 aa mouse beta 2/CD18 ECD shares 91% aa sequence identity with rat, and 80-82% with human, bovine, canine, and porcine beta 2 ECD.

• References:

1. Larson, R.S. et al. (1989) J. Cell Biol. 108:703.

2. Kishimoto, T.K. et al. (1987) Cell 48:681.

3. Hogg, N. et al. (2011) Nat. Rev. Immunol. 11:416.

4. Beglova, N. et al. (2002) Nat. Struct. Biol. 9:282.

5. Shimaoka, M. et al. (2003) Immunity 19:391.

6. Lu, C. et al. (2004) J. Immunol. 173:3972.

7. Cairo, C.W. et al. (2006) Immunity 25:297.

8. Nortamo, P. et al. (1991) J. Immunol. 146:2530.

9. de Fougerolles, A.R. and T.A. Springer (1992) J. Exp. Med. 175:185.

10. Ostermann, G. et al. (2002) Nat. Immunol. 3:151.

11. Heit, B. et al. (2005) J. Cell Sci. 118:5205.

12. Semmrich, M. et al. (2005) J. Exp. Med. 201:1987.

13. Dixit, N. et al. (2011) J. Immunol. 187:472.

14. Reisman, N.M. et al. (2011) Blood 118:5851.

15. Kishimoto, T.K. et al. (1987) Cell 50:193.

• Entrez Gene IDs:

  3683 (Human)

• Alternate Names:

  Integrin alpha L beta 2