• Purity

  >90%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie? Blue Staining.

• Endotoxin Level

  <0.01 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to induce Topflash reporter activity in HEK293T human embryonic kidney cells. The ED    ₅₀ for this effect is 10?60 ng/mL in the presence of 10 ng/mL Recombinant Mouse Wnt?3a (Catalog # ).

• Source

  Chinese Hamster Ovary cell line, CHO-derived Met1-Pro234

• Accession #

• N-terminal Sequence    
  Analysis

  Ala19

• Predicted Molecular Mass

  24.1 kDa (monomer)

• SDS-PAGE

  30-36 kDa, 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: R-Spondin 4

R-Spondin 4 (RSPO4, roof plate-specific spondin 4), also called cysteine?rich and single thrombospondin domain containing-4 (Cristin 4), is an ~33 kDa secreted heparin-binding protein that shares ~35% amino acid (aa) identity with three other R?Spondin family members (1?3). All are positive modulators of Wnt/ beta -catenin signaling, but vary in activity (2). R?Spondins regulate Wnt/ beta -catenin by competing with the Wnt antagonist DKK-1 for binding to the Wnt co-receptors LRP-6 and Kremen, reducing their DKK-1-mediated internalization (1, 4). Like other R?spondins, human R?Spondin 4 (228 aa) contains a signal sequence (aa 1?19), two adjacent cysteine?rich furin-like domains (aa 85-128) with one potential tyrosine phosphorylation site (aa 114), followed by a thrombospondin (TSP?1) motif (aa 137?197) and a region rich in basic residues (aa 199?228). Mature human R?Spondin 4 shares 81%, 81%, 84%, 84% and 86% aa identity with mouse, rat, equine, canine and bovine R?Spondin 4, respectively. Of two potential isoforms, one lacks the TSP-1 domain, while another terminates at aa 224 (5). Each R?Spondin has a distinct expression pattern (6). In the mouse, R?Spondin 4 mRNA is found during development of limb bud mesenchyme, nail beds, heart and teeth (6?8). In humans, mutations of R?Spondin 4 have been found to cause anonychia, a condition in which fingernails and toenails are absent (8?10).

• References:

1. Nam, J.-S. et al. (2006) J. Biol. Chem. 281:13247.

2. Kim, K.-A. et al. (2008) Mol. Biol. Cell 19:2588.

3. Hendrickx, M. and L. Leyns (2008) Develop. Growth Differ. 50:229.

4. Binnerts, M.E. et al. (2007) Proc. Natl. Acad. Sci. USA 104:14700.

5. Entrez Accession # NP_001035096, EAX10652.

6. Nam, J.-S. et al. (2007) Gene Expr. Patterns 7:306.

7. Pemberton, T.J. et al. (2007) Dev. Dyn. 236:2245.

8. Ishii, Y. et al. (2008) J. Invest. Dermatol. 128:867.

9. Blaydon, D.C. et al. (2006) Nat. Genet. 38:1245.

10. Bergmann, C. et al. (2006) Am. J. Hum. Genet. 79:1105.

• Long Name:

  Roof Plate-specific Spondin 4

• Entrez Gene IDs:

  343637 (Human); 228770 (Mouse)

• Alternate Names:

  C20orf182; chromosome 20 open reading frame 182; Cristin 4; CRISTIN4; dJ824F16.3; FLJ16018; hRspo4; Roof plate-specific spondin-4; RSPO4; RSpondin 4; R-Spondin 4; R-spondin family, member 4; R-spondin-4