• 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 A431 human epithelial carcinoma cells.

  When 5 x 10⁴ cells/well are added to rhSMOC-1 coated plates, cell adhesion is enhanced in a dose dependent manner after 75 minutes at 37 °C. The ED₅₀ for this effect is 0.5-2 μg/mL.

• Source

  Mouse myeloma cell line, NS0-derived His27-Val434, with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  His27 & Ile36    
   

• Predicted Molecular Mass

  46.1 kDa

• SDS-PAGE

  60-65 kDa, reducing conditions

Background: SMOC-1

SMOC-1 (secreted, or SPARC-related, modular calcium-binding protein 1) is a 70 - 90 kDa secreted glycoprotein that is a member of the SPARC family of matricellular molecules (1). Mature human SMOC-1 is 408 amino acids (aa) in length. It contains one Kazal-like domain (aa 42 - 87), two thyroglobulin type-1 (TY) segments (aa 92 - 159 and 224 - 292) and two EF-hand sequences (aa 359 - 394 and 396 - 431). One potential splice variant contains a 16 aa region of alternate sequence between the TY domains, a 7 aa deletion between the TY and EF-hand domains, and three alternate aa at the C-terminus. Mature human SMOC-1 shares 92% aa identity with mouse and rat SMOC-1 and 97%, 96% and 95% aa identity with canine, bovine and porcine SMOC-1, respectively. The principal difference between rodents and other mammals is an additional 19 aa near the C-terminus of rodent SMOC-1. Like other matricellular proteins, SMOC-1 is primarily expressed in basement membranes, although it has also been found in other extracellular matrices and the oocyte zona pellucida (1). It is present early in mouse embryogenesis, and is produced by cells deriving from all three germ layers (4). Recombinant bacterially produced human SMOC-1 and SMOC-2 were both shown to bind the acute phase protein, C-reactive protein, and the adhesion proteins, fibulin and vitronectin (2). A signaling role for SMOC-1 was shown in rat mesangial cells: induction of nitric oxide in response to inflammatory cytokines downregulates SMOC-1 which, in turn, downregulates expression of TGF-beta and TGF-beta -regulated genes. This mechanism is proposed to limit the profibrotic effects of TGF-beta, for example in the glomerulus (5). In Xenopus, the SMOC paralog has been shown to antagonize BMP activity.

• References:

1. Vannahme, C. et al. (2002) J. Biol. Chem. 277:37977.

2. Novinec, M. et al. (2008) Protein Expr. Purif. 62:75.

3. Entrez Q8BLY1 and EDL02699.

4. Gersdorff, N. et al. (2006) Histochem. Cell Biol. 126:705.

5. Dreieicher, E. et al. (2009) J. Am. Soc. Nephrol. 20:1963.

6. Thomas, J.T. et al. (2009) J. Biol. Chem. 284:18994.

• Long Name:

  Secreted Modular Calcium-binding Protein 1

• Entrez Gene IDs:

  64093 (Human); 64075 (Mouse); 314280 (Rat)

• Alternate Names:

  Secreted modular calcium-binding protein 1; SMOC1; SMOC-1; SPARC related modular calcium binding 1; SPARC-related modular calcium-binding protein 1