Phospho-IGF-I Receptor β (Tyr1316) Antibody #28897

Type I insulin-like growth factor receptor (IGF-IR) is a transmembrane receptor tyrosine kinase that is widely expressed in many cell lines and cell types within fetal and postnatal tissues (1-3). Receptor autophosphorylation follows binding of the IGF-I and IGF-II ligands. Three tyrosine residues within the kinase domain (Tyr1131, Tyr1135, and Tyr1136) are the earliest major autophosphorylation sites (4). Phosphorylation of these three tyrosine residues is necessary for kinase activation (5,6). Insulin receptors (IRs) share significant structural and functional similarity with IGF-I receptors, including the presence of an equivalent tyrosine cluster (Tyr1146/1150/1151) within the kinase domain activation loop. Tyrosine autophosphorylation of IRs is one of the earliest cellular responses to insulin stimulation (7). Autophosphorylation begins with phosphorylation at Tyr1146 and either Tyr1150 or Tyr1151, while full kinase activation requires triple tyrosine phosphorylation (8).
Phosphorylation of IGF-I receptor on Tyr1346 (equivalent to Tyr1316 in mature protein) was identified at Cell Signaling Technology (CST) using PhosphoScan^®, CST's LC-MS/MS platform for phosphorylation site discovery (9). Phosphorylation of IGF-I receptor on Tyr1346 was also reported by several other labs in select carcinoma cell lines (10,11).