Description
Description: This assay employs a two-site sandwich ELISA to quantitate FOXO3 in samples. An antibody specific for FOXO3 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any FOXO3 present is bound by the immobilized antibody. After removing any unbound substances, a biotin-conjugated antibody specific for FOXO3 is added to the wells. After washing, Streptavidin conjugated Horseradish Peroxidase (HRP) is added to the wells. Following a wash to remove any unbound avidin-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of FOXO3 bound in the initial step. The color development is stopped and the intensity of the color is measured.
Overview: FOXO3 belongs to the O subclass of the forkhead family of transcription factors which are characterized by a distinct fork head DNA binding domain. There are three other FoxO family members in humans, FOXO1, FOXO4 and FOXO6. These transcription factors share the ability to be inhibited and translocated out of the nucleus (aside from FOXO6, which may be constitutively nuclear) on phosphorylation by proteins such as Akt/PKB in the PI3K signalling pathway. Other post-translational modifications including acetylation and methylation are seen and can result in increased or altered FOXO3a activity. This protein likely functions as a trigger for apoptosis through upregulation of genes necessary for cell death, such as Bim and PUMA, or downregulation of anti-apoptotic proteins such as FLIP