• Purity

  >90%, by SDS-PAGE under reducing conditions and visualized by silver stain.

• Endotoxin Level

  <1.0 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its binding ability in a functional ELISA. Immobilized Recombinant Mouse Kremen-1 at 4 µg/mL (100 µL/well) can bind Recombinant Human Dkk-1 (Catalog # ) with an apparent K    _d <10 nM.  

• Source

  Mouse myeloma cell line, NS0-derived Ala20-Gly395, with a C-terminal 10-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Ala20

• Structure / Form

  Monomer

• Predicted Molecular Mass

  42.6 kDa

• SDS-PAGE

  72-85 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: Kremen-1

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) co-receptor (2, 3). Within the Dkk family, Dkk-1 and -4 bind directly to the LRP5/6 co-receptor 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 co-operates 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-1 cDNA encodes a 473 amino acid (aa) glycosylated protein with a putative 19 aa signal peptide, a 372 aa extracellular domain, a 21 aa transmembrane domain and a 60 aa cytoplasmic domain. In the extracellular domain, it shares 92% and 41% amino acid sequence identity with human Kremen-1 and mouse Kremen-2, respectively. Mouse Kremen-1 is widely expressed in diverse embryonic (apical ectodermal ridge of the developing fore- and hindlimb buds, telencephalon and the first brachial arch, myotome and sensory tissues) and adult (lung, heart, kidney, skeletal muscle and testis) tissues (1).

• 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 1

• Entrez Gene IDs:

  83999 (Human); 84035 (Mouse)

• Alternate Names:

  EC 3.4.21; FLJ31863; KREMEM1; kremen protein 1; KREMEN; Kremen1; Kremen-1; kringle containing transmembrane protein 1; kringle containing transmembrane protein; Kringle domain-containing transmembrane protein 1; kringle-coding gene marking the eye and the nose; Kringle-containing protein marking the eye and the nose; KRM1; KRM1Dickkopf receptor