Invitrogen™ IRS1 (Phospho) [pS312] Human ELISA Kit

Description

Kit is designed to detect and quantify the level of IRS1 (Phospho) [pS312] in fresh or frozen human cell lysates. Cross-reactivity has been observed in mouse and rat cells. The assay recognizes both natural and recombinant IRS1 (Phospho) [pS312]. Principle of the method A monoclonal capture antibody specific for IRS1 (Phospho) [pS312] has been coated onto the wells of the 96-well plate. During the first incubation, standards of known content and unknown samples are pipetted into the wells and the antigen binds to the immobilized (capture) antibody. After washing, a rabbit antibody specific for the target protein is added to the wells and serves as a detection antibody by binding to the immobilized protein captured during the first incubation. After washing, a horseradish peroxidase labeled anti-rabbit IgG is added. This binds to the detection antibody to complete the four member sandwich. After a third incubation and washing to remove all the unbound enzyme, a substrate solution (TMB) is added, which is acted upon by the bound enzyme to produce color. The intensity of this colored product is directly proportional to the concentration of target protein present in the original specimen and the optical density can be read on a standard microplate reader. Rigorous validation Each manufactured lot of this ELISA kit is quality tested for criteria such as sensitivity, specificity, precision, and lot-to-lot consistency. See manual for more information on validation.

IRS-1, a major substrate of the insulin receptor, is phosphorylated in response to stimulation of cells by insulin, insulin-like growth factor 1 (IGF-1) and interleukin 4 (IL-4). IRS-1 is phosphorylated on serine, threonine and tyrosine residues in a variety of tissues. An insulin-sensitive serine/threonine kinase casein kinase II mediates a portion of the insulin-stimulated serine/threonine phosphorylation of overexpressed IRS-1 in vivo. Thr 502 is identified as the major casein kinase II-catalyzed phosphorylation site in rat IRS-1, and Ser 99 is an additional phosphorylation site catalyzed by casein kinase II. Thus, casein kinase II-catalyzed phosphorylation of IRS-1 may be a component of the intracellular insulin signaling cascade. IRS-1 contains three putative binding sites for 14-3-3 (Ser 270, Ser 374 and Ser 641) and the motif around Ser 270 is located in the phosphortyrosine binding domain of IRS-1, which is responsible for the interaction with the insulin receptor.

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