Description
Principle of the Assay: The Human HER3 ELISA (Enzyme-Linked Immunosorbent Assay) kit is an in vitro enzyme-linked immunosorbent assay for the quantitative measurement of Human HER3 in Cell Culture Supernates, Serum, Plasma. This assay employs an antibody specific for Human HER3 coated on a 96-well plate. Standards and samples are pipetted into the wells and HER3 present in a sample is bound to the wells by the immobilized antibody. The wells are washed and biotinylated anti-Human HER3 antibody is added. After washing away unbound biotinylated antibody, HRP-conjugated streptavidin is pipetted to the wells. The wells are again washed, a TMB substrate solution is added to the wells and color develops in proportion to the amount of HER3 bound. The Stop Solution changes the color from blue to yellow, and the intensity of the color is measured at 450 nm.
Background: Receptor tyrosine-protein kinase erbB-3, also known as HER3 (human epidermal growth factor receptor 3), is a membrane bound protein that in humans is encoded by the ERBB3 gene. ErbB3 has been shown to bind the ligands heregulin and NRG-2. Ligand binding causes a change in conformation that allows for dimerization, phosphorylation, and activation of signal transduction. ErbB3 can heterodimerize with any of the other three ErbB family members. The theoretical ErbB3 homodimer would be non-functional because the kinase-impaired protein requires transphosporylation by its binding partner to be active. Unlike the other ErbB receptor tyrosine kinase family members which are activated through autophosphorylation upon ligand binding, ErbB3 is found to be kinase impaired, having only 1/1000th the autophosphorylation activity of EGFR and no ability to phosphorylate other proteins. Therefore, ErbB3 must act as anallosteric activator