• Purity

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

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its binding ability in a functional ELISA. Immobilized rmKremen-2 at 4 μg/mL (100 μL/well) can bind rhDkk-1 with an apparent K    _D <10 nM.  

• Source

  Mouse myeloma cell line, NS0-derived Gly25-Thr371, with a C-terminal 10-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Gly25

• Predicted Molecular Mass

  38.4 kDa

• SDS-PAGE

  53-58 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: Kremen-2

Kremen (Kringle-containing protein marking the eye and the nose) proteins are type I transmembrane proteins that contain extracellular kringle, WSC and CUB domains and an intracellular region without any conserved motifs (1). Two related members, Kremen-1 and -2, have been identified. Kremens bind a subset of the secreted Dickkopf (Dkk) proteins (Dkk-1, -2, and -4) with high affinity to modulate the canonical Wnt signaling pathway that is transduced by the ternary receptor complex composed of Wnt, the seven-transmembrane domain receptor Frizzled, and the LDL-receptor-related protein 5/6 (LRP5/6) coreceptor (2, 3). Within the Dkk family, Dkk-1 and -4 bind directly to the LRP5/6 coreceptor to antagonize the canonical Wnt/ beta -catenin signaling pathway, but not the planar cell polarity (PCP) signaling pathway that does not involve LRP5/6 (4). In contrast, Dkk-3 has no effect on Wnt signaling and Dkk-2 can function either as an LRP agonist or antagonist, depending on whether the cell expresses Kremen (5). Kremen cooperates with Dkk to antagonize Wnt signaling via formation of a Kremen-Dkk-LRP ternary complex that triggers the internalization and clearance of the complex from the cell surface (3). All three extracellular domains but not the cytoplasmic region of a membrane anchored Kremen are needed for binding to the second cysteine-rich domain of Dkks (3). Mouse Kremen-2 cDNA encodes a 461 amino acid (aa) glycosylated protein with a putative 24 aa signal peptide, a 339 aa extracellular domain, a 23 aa transmembrane domain and a 75 aa cytoplasmic domain. In the extracellular domain, it shares 88% and 41% amino acid sequence identity with human Kremen-2 and mouse Kremen-1, respectively.

• References:

1. Nakamura, T. et al. (2001) Biochim Biophys Acta 1518:63.

2. Davidson G. et al. (2002) Development 129:5587.

3. Mao, B. et al. (2002) Nature 417:664.

4. Zorn, A.M. (2001) Curr. Biol. 11:R592.

5. Mao, B. and C. Niehrs (2003) Gene 302:179.

• Long Name:

  Kringle-containing Transmembrane Protein 2

• Entrez Gene IDs:

  79412 (Human); 73016 (Mouse)

• Alternate Names:

  Dickkopf receptor 2; kremen protein 2; Kremen2; Kremen-2; kringle containing transmembrane protein 2; Kringle domain-containing transmembrane protein 2; KRM2Kringle-containing protein marking the eye and the nose; MGC10791; MGC16709