More info
Assay Range | 62.5--4000 pg/mL |
Sensitivity | 10.0 pg/mL |
Size | 96T |
Storage | Store at 2 - 8ºC. Keep reconstituted standard and detection Ab at -20 ºC |
Assay Principle | Sandwich ELISA |
Sample volume | 100 µL final volume, dilution factor varies on samples |
Detection Method | Chromogenic |
Kit Components
1. Recombinant Human DKK-1 standard: 2 vials
2. One 96-well plate precoated with anti- Human DKK-1 Ab
3. Sample diluent buffer: 12 mL - 1
4. Detection antibody: 130 µL, dilution 1:100
5. Streptavidin-HRP: 130 µL, dilution 1:100
6. Antibody diluent buffer: 12 mL x1
7. Streptavidin-HRP diluent buffer: 12 mL x1
8. TMB developing agent: 10 mL x1
9. Stop solution: 10 mL x1.
10. Washing solution (20x): 25 mL x1.
Background
Dickkopf related protein 1 (Dkk-1) is the founding member of the Dickkopf family that includes Dkk-1, -2, -3, -4, and a related protein, Soggy. Dkk proteins contain two conserved cysteine-rich domains separated by a linker region. The C-terminal domain, which contains a colipase fold with a conserved pattern of ten cysteine residues, is necessary and sufficient for Wnt inhibition. Mature human Dkk-1 is a glycosylated protein that shows 86% and 87% amino acid (aa) sequence identity with mouse and rat Dkk-1, respectively. It also shows 42% and 36% aa identity with human Dkk-2 and Dkk-4, respectively.
Dkk-1 is an antagonist of the canonical Wnt signaling pathway, which is activated by Wnt engagement of a receptor complex composed of the Frizzled proteins and one of two low-density lipoprotein receptor-related proteins, LRP5 or LRP6. Dkk-1 antagonizes Wnt by forming ternary complexes of LRP5/6 with Kremen1 or Kremen2. Internalization of the Dkk-1/LRP6/Krm2 complex downregulates Wnt signaling. Dkk-1 has also been proposed to have Wnt-independent activity in some human cancer cell lines. Dkk-1 is expressed throughout embryogenesis and antagonizes Wnt-7a during limb development, in developing neurons, keratinocytes, hair follicles, and the retina of the eye. Postnatally, Dkk-1 is expressed mainly by osteoblasts and osteocytes. The balance between Wnt signaling and Dkk-1 inhibition is critical for bone formation and homeostasis. Insufficient or excess Dkk-1 activity in bone results in increased or decreased bone density, respectively. It is shown that high Dkk-1 expression may be pathogenic in conditions where bone is eroded, such as rheumatoid arthritis, multiple myeloma, Paget’s disease, and glucocorticoid-induced osteoporosis.