• Purity

  >95%, by SDS-PAGE under reducing conditions and visualized by silver stain.

• 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 HEK293 human embryonic kidney cells. Agnihotri, R.     et al. (2001) J. Biol. Chem.     276:28261. When 1 x 10    ⁵ cells/well are added to a Recombinant Mouse (rm) Osteopontin/OPN coated plate, cell adhesion is enhanced in a dose-dependent manner after 1 hour incubation at 37 °C. The ED    ₅₀  for this effect is 0.25-1.5 µg/mL. Recombinant Human Coagulation Factor II/Thrombin (Catalog # ) proteolytic treatment of this rmOsteopontin can increase HEK293 cell adhesion by about 10-fold.

• Source

  Mouse myeloma cell line, NS0-derived Leu17-Asn294 (Glu99Gly), with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Leu17

• Predicted Molecular Mass

  31.5 kDa

• SDS-PAGE

  30 kDa and a 65 kDa doublet, reducing conditions

Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Background: Osteopontin/OPN

Osteopontin (OPN), previously called SPP1 (secreted phosphoprotein 1), Eta-1 (early T lymphocyte activation 1) or BSP (bone sialoprotein), is a secreted molecule in the SIBLING (small integrin-binding ligand N-linked glycoprotein) family of non-collagenous matricellular proteins (1-3). Mouse OPN is synthesized as a 294 amino acid (aa) precursor protein with a 16 aa signal peptide and a 278 aa mature protein (3). Mature mouse OPN shares 79% and 64% aa sequence identity with rat and human OPN, respectively. OPN is highly acidic and has 26 potential Ser/Thr phosphorylation sites and a C‑terminal CD44 binding site (1-4). Depending on tissue-specific modification by O- and N-glycosylation, sulfation, phosphorylation and transglutamination, OPN can be detected at 45-75 kDa (5, 6). The central region of OPN contains RGD and non-RGD binding sites for multiple integrins (3, 4). Adjacent to the RGD motif is the sequence SLAYGLR (SVVYGLR in human) which serves as a cryptic binding site for additional integrins: it is masked in full length OPN but is exposed following OPN cleavage by thrombin in tumors and sites of tissue injury  
(6-8). OPN can also be cleaved by MMP-3, -7, -9, and -12 within the SLAYGLR motif and at sites closer to the C-terminus (8, 9). OPN is widely expressed and is prominent in mineralized tissues. It inhibits bone mineralization and kidney stone formation, and promotes inflammation and cell ad­hesion and migration (1, 2, 4, 6). Its expression is up-regulat­ed during inflammation, obesity, atherosclerosis, cancer, and tissue damage, and contributes to the pathophysiology of these conditions (1, 2, 6, 9, 10).

• References:

1. Scatena, M. et al. (2007) Arterioscler. Thromb. Vasc. Biol. 27:2302.

2. Rangaswami, H. et al. (2006) Trends Cell Biol. 16:79.

3. Miyazaki, Y. et al. (1990) J. Biol. Chem. 265:14432.

4. Weber, G.F. et al. (2002) J. Leukoc. Biol. 72:752.

5. Keykhosravani, M. et al. (2005) Biochemistry 44:6990.

6. Kazanecki, C.C. et al. (2007) J. Cell. Biochem. 102:912.

7. Senger, D.R. et al. (1994) Mol. Biol. Cell 5:565.

8. Yokosaki, Y. et al. (2005) Matrix Biol. 24:418.

9. Takafuji, V. et al. (2007) Oncogene 26:6361.

10. Kiefer, F.W. et al. (2010) Diabetes 59:935.

• Long Name:

  Secreted Phosphoprotein 1 [BNSP]

• Entrez Gene IDs:

  6696 (Human); 20750 (Mouse); 25353 (Rat); 281499 (Bovine)

• Alternate Names:

  BNSP; Bone sialoprotein 1; Eta-1; MGC110940; Nephropontin; OPN; Osteopontin; secreted phosphoprotein 1bone sialoprotein I, early T-lymphocyteactivation 1); secreted phosphoprotein-1 (osteopontin, bone sialoprotein); Spp1; SPP-1; SPP1/CALPHA1 fusion; Urinary stone protein; uropontin