• Species Reactivity

  Human

• Specificity

  Detects human CD42b/GPIb alpha  in direct ELISAs and Western blots.

• Source

  Monoclonal Mouse IgG1 Clone # 486805

• Immunogen

  Mouse myeloma cell line NS0-derived recombinant human CD42b/GPIb alpha    
  His17-Leu505    
  Accession # P07359

• Formulation

  Supplied 0.2 mg/mL in a saline solution containing BSA and Sodium Azide.

• Label

  Alexa Fluor 405

Applications

• 
  

  Recommended    
  Concentration

  Sample

• Flow Cytometry

  0.25-1 µg/10    ⁶ cells

  Human CD41    ⁺ platelets

• 
  

Please Note: Optimal dilutions should be determined by each laboratory for each application.  are available in the Technical Information section on our website.

Preparation and Storage

• Shipping

  The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.

• Stability & Storage

  Store the unopened product at 2 - 8 °C. Do not use past expiration date.

Background: CD42b/GPIb alpha

Platelet glycoprotein Ib alpha chain (GPIb  alpha ), also known as CD42b, is a 145 kDa type I transmembrane protein that is a member of the leucine-rich repeat (LRR) family of ligand binding proteins (1‑3). It is expressed by platelets as the ligand-binding subunit of the platelet GPIb-IX-V complex (4). Human CD42b contains a 16 amino acid (aa) signal sequence, a 489 aa extracellular domain (ECD), a 21-aa transmembrane domain, and a 100 aa cytoplasmic region. The ECD contains 8 LRRs, with # 2, 3, and 4 having been demonstrated to regulate shear-dependent adhesion to von Willebrand factor (vWF) (5, 6). The LRRs are followed by a thrombin-binding anionic region that includes three sulfated tyrosines, a sialomucin domain with N- and O-linked carbohydrates, and two cysteines near the membrane that allow dimerization (1‑6). Four human isoforms with 1 to 4 repeats of aa 398‑411 within the sialomucin domain of mature CD42b are known to exist but have unknown significance (7). The ECD of human CD42b shares 48‑51% aa identity with mouse, rat, bovine, and canine CD42b. The metalloproteinase TACE/ADAM17 constitutively and inducibly cleaves CD42b, between Gly480 and Val481. This releases a soluble form called glycocalicin that circulates at ~2 μg/mL (8, 9). CD42b binding to ligands such as thrombin, kininogen, and coagulation factors XI and XII helps to initiate platelet activation and coordinate the coagulation cascade (1, 10‑12). Binding of CD42b to vWF or thrombospondin in the plasma or matrix, vWF or P-selectin on endothelial cells, or the integrin  alpha M beta 2 (MAC-1) on myeloid cells, controls response to vascular injury (1, 13). Bernard-Soulier syndrome and platelet-type von Willebrand disease are platelet function disorders that can be caused by mutations in CD42b (1, 14).

• References:

1. Andrews, R.K. et al. (2007) Arterioscler. Thromb. Vasc. Biol. 27:1511. 

2. Lopez, J.A. et al. (1987) Proc. Natl. Acad. Sci. USA 84:5615.

3. Wenger, R.H. et al. (1988) Biochem. Biophys. Res. Commun. 156:389. 

4. Luo, S-Z. et al. (2007) Blood 109:603. 

5. Uff, S. et al. (2002) J. Biol. Chem. 277:35657.

6. Shen, Y. et al. (2006) J. Biol. Chem. 281:26419.

7. Ishida, F. et al. (1995) Blood 86:1356.

8. Gardiner, E.E. et al. (2007) J. Thromb. Haemost. 5:1530.

9. Beer, J.H. et al. (1994) Blood 83:691.

10. Adam, F. et al. (2003) Eur. J. Biochem. 270:2959.

11. Baglia, F.A. et al. (2004) J. Biol. Chem. 279:49323.

12. Bradford, H.N. et al. (2000) J. Biol. Chem. 275:22756.

13. Wang, Y. et al. (2005) Circulation 112:2993.

14. Othman, M. et al. (2005) Blood 105:4330.

• Long Name:

  Glycoprotein lb [Platelet] alpha

• Entrez Gene IDs:

  2811 (Human); 14723 (Mouse)

• Alternate Names:

  Antigen CD42b-alpha; BP1BA; BSS; CD42b antigen; CD42b; CD42b-alpha; glycoprotein Ib (platelet), alpha polypeptide; Glycoprotein Ibalpha; GP1B; GP1BA; GPIb alpha; GP-Ib alpha; GPIbA; GPIb-alpha; MGC34595; platelet glycoprotein Ib alpha chain; platelet membrane glycoprotein 1b-alpha subunit