Phospho-IGF-I Receptor b (Tyr1131) Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of IGF-I receptor b protein when phosphorylated at Tyr1131. A Phospho-IGF-I Receptor b (Tyr1131) Rabbit Antibody has been coated onto the microwells. After incubation with cell lysates, phospho-IGFI Receptor b is captured by the coated antibody. Following extensive washing, an IGF-I Receptor Mouse Antibody is added to detect the captured phospho-IGF-I receptor protein. Anti-mouse IgG, HRP-linked Antibody is then used to recognize the bound detection antibody. HRP substrate, TMB, is added to develop color. The magnitude of absorbance for this developed color is proportional to the quantity of IGF-I receptor protein phosphorylated at Tyr1131.
Type I insulin-like growth factor receptor (IGF-IR), a transmembrane receptor tyrosine kinase, is widely expressed in many cell types within fetal and postnatal tissues, and in many cell lines (1-3). Upon binding to its ligands, IGF-I and IGF-II, receptor autophosphorylation occurs. The triple tyrosine cluster within the kinase domain (Tyr1131, Tyr1135 and Tyr1136) is the earliest major site of autophosphorylation (4). Phosphorylation of these three tyrosine residues is necessary for kinase activation (5,6). Insulin receptors (IRs) share significant similarity with IGF-I receptors in both structure and function, including an equivalent triple tyrosine cluster within the activation loop of the kinase domain (Tyr1146, Tyr1150 and Tyr1151). Tyrosine autophosphorylation of insulin receptor is one of the earliest cellular responses to insulin stimulation (7). Autophosphorylation begins with phosphorylation of Tyr1146 and either Tyr1150 or Tyr1151. Full kinase activation requires the triple tyrosine phosphorylation (8).