Description
Introduction: Cadherins (Calcium dependent adhesion molecules) are a class of type-1 transmembrane proteins. They play important roles in cell adhesion, ensuring that cells within tissues are bound together. They are dependent on calcium (Ca2+) ions to function, hence their name. Different members of the cadherin family are found in different locations. E-cadherins are found in epithelial tissue; N-cadherins are found in neurons; and P-cadherins are found in the placenta. T-cadherins have no cytoplasmic domains and must be tethered to the plasma membrane. E-cadherin (epithelial) is the most well-studied member of the family. It consists of 5 cadherin repeats (EC1 ~ EC5) in the extracellular domain, one transmembrane domain, and an intracellular domain that binds p120-catenin and beta-catenin. The intracellular domain contains a highly-phosphorylated region vital to beta-catenin binding and therefore to E-cadherin function. Beta-catenin can also bind to alpha-catenin. Alpha-catenin participates in regulation of actin-containing cytoskeletal filaments. In epithelial cells, E-cadherin-containing cell-to-cell junctions are often adjacent to actin-containing filaments of the cytoskeleton. E-cadherin is first expressed in the 2-cell stage of mammalian development, and becomes phosphorylated by the 8-cell stage, where it causes compaction. In adult tissues, E-cadherin is expressed in epithelial tissues, where it is constantly regenerated with a 5-hour half-life on the cell surface. Loss of E-cadherin function or expression has been implicated in cancer progression and metastasis. E-cadherin downregulation decreases the strength of cellular adhesion within a tissue, resulting in an increase in cellular motility. This in turn may allow cancer cells to cross the basement membrane and invade surrounding tissues. E-cadherin is also used by pathologists to diagnose different kinds of breast cancer. When compared with invasive duct carcinoma, E-cadherin expression is markedly reduced or absent in the great majority of invasive lobular carcinomas when studied by immunohistochemistry.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to E-Cad. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for E-Cad and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB (3,3',5,5' tetramethyl-benzidine) substrate solution is added to each well. Only those wells that contain E-Cad, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm +/- 2 nm. The concentration of E-Cad in the samples is then determined by comparing the O.D. of the samples to the standard curve